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1
Mandhare, M. M., S. A. Gangal, M. S. Setty, and R. N. Karekar. "Performance Comparison of Thin and Thick Film Microstrip Rejection Filters." Active and Passive Electronic Components 13, no. 1 (1988): 45–54. http://dx.doi.org/10.1155/1988/62434.
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A performance comparison of microstripline circuits using thin and thick film techniques has been studied, in which a Microstrip rejection filter, in the X-band of microwaves, is used as test circuit. A thick film technique is capable of giving good adhesive films with comparable d.c. sheet resistivity, but other parameters such as open area (porosity), particle size, and edge definition are inferior to thin-film microstrip filters. Despite this drawback, the average value of transmission, transmission loss, reflection coefficient, resonant rejection frequency, and quality factor for thick-film filters indicate that screen printed Ag films are intermediate between thin-film1,2,9and etched-thick-film9microstrip filters in performance, making it a feasible method for microstrip circuits.
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Kabe, A., and I. Morooka. "Polymer Thick Film Circuits in Japan." Microelectronics International 2, no. 2 (February 1985): 24–26. http://dx.doi.org/10.1108/eb044174.
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Rane, Sunit, and Vijaya Puri. "A Study on Effect of Line Width, Composition and Firing Temperature on the Microstripline Properties." Active and Passive Electronic Components 23, no. 3 (2000): 163–73. http://dx.doi.org/10.1155/apec.23.163.
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The transmittance and reflectance of microstriplines of different widths, fabricated by thick film and thin film technology are studied in the X and Ku band (8–18 GHz). The fritless thick film Ag pastes with different binder composition was formulated indigenously and screen-printed the microstriplines on alumina substrate. These microstriplines were compared with the microstriplines made from ESL (USA) pastes and also Cu thin film circuits. The effect of line width, composition and firing temperature on the thick film microstriplines was investigated. The transmittance of all the indigenously prepared Ag thick film paste compared well with microstriplines prepared with ESL pastes. All these thick film pastes gave good transmittance upto 18.0 GHz. The results indicate firing at 700℃ gives best films, and also 18 mil or 20-mil line width is more suitable than conventional 25-mil line width if thick films are used for metallization upto 18.0 GHz.
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Storbeck, I., H. Balke, and M. Wolf. "Substrate Bowing of Multilayer Thick Film Circuits." Microelectronics International 3, no. 3 (March 1986): 21–23. http://dx.doi.org/10.1108/eb044243.
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Miś, Edward, Andrzej Dziedzic, and Witold Mielcarek. "Microvaristors in thick-film and LTCC circuits." Microelectronics Reliability 49, no. 6 (June 2009): 607–13. http://dx.doi.org/10.1016/j.microrel.2009.03.002.
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Singh, Awatar, M. Prudenziati, and B. Morten. "Reverse photolithographic technique for thick film circuits." Microelectronics Reliability 25, no. 1 (January 1985): 61–63. http://dx.doi.org/10.1016/0026-2714(85)90442-1.
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Zhang, Weiguang, Jijun Li, Yongming Xing, Xiaomeng Nie, Fengchao Lang, Shiting Yang, Xiaohu Hou, and Chunwang Zhao. "Experimental Study on the Thickness-Dependent Hardness of SiO2 Thin Films Using Nanoindentation." Coatings 11, no. 1 (December 27, 2020): 23. http://dx.doi.org/10.3390/coatings11010023.
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SiO2 thin films are widely used in micro-electro-mechanical systems, integrated circuits and optical thin film devices. Tremendous efforts have been devoted to studying the preparation technology and optical properties of SiO2 thin films, but little attention has been paid to their mechanical properties. Herein, the surface morphology of the 500-nm-thick, 1000-nm-thick and 2000-nm-thick SiO2 thin films on the Si substrates was observed by atomic force microscopy. The hardnesses of the three SiO2 thin films with different thicknesses were investigated by nanoindentation technique, and the dependence of the hardness of the SiO2 thin film with its thickness was analyzed. The results showed that the average grain size of SiO2 thin film increased with increasing film thickness. For the three SiO2 thin films with different thicknesses, the same relative penetration depth range of ~0.4–0.5 existed, above which the intrinsic hardness without substrate influence can be determined. The average intrinsic hardness of the SiO2 thin film decreased with the increasing film thickness and average grain size, which showed the similar trend with the Hall-Petch type relationship.
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Sgriccia, Matt, Frank Sandoval, and Ryan Persons. "Thick Film Materials for High Power Hybrid Circuits on Aluminum Nitride." International Symposium on Microelectronics 2017, no. 1 (October 1, 2017): 000411–16. http://dx.doi.org/10.4071/isom-2017-wp34_068.
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Abstract For over 40 years, the substrate of choice for designing and fabricating traditional hybrid circuits has been alumina. It has provided the required mechanical strength, electrical resistivity, and thermal performance needed for proper circuit operation. Over the past several years however, we have experienced a shift in hybrid technology towards electronic devices with highly complex, dense circuit configurations that produce more power and consequently, more heat than previous designs. This requires the use of a substrate with a higher thermal conductivity to properly manage the heat transfer and dissipation in order to maintain optimum performance and functionality of the end device. The thermal properties displayed by aluminum nitride provide design engineers with a reliable alternative to traditional alumina. While creating new and exciting possibilities, the use of aluminum nitride also creates a different set of challenges for thick film suppliers and circuit fabricators. Due to the thermal expansion mismatch, as well as the chemical changes that occur to the substrate which affect adhesion during the firing process, thick film pastes previously suitable for alumina are typically not compatible with aluminum nitride. To overcome this challenge and the performance demands of high power, high reliability circuit applications, a new line of RoHS and REACH compliant thick film pastes has been developed. The following conductors are available: silver, silver/palladium, silver/platinum, copper, and gold. In addition, we have developed two resistor pastes and a compatible overglaze. This paper will discuss the aforementioned thick films and their critical performance properties before and after reliability testing. This includes adhesion for the conductors, resistance and TCR for the resistors.
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Rebenklau, L., P. Gierth, and H. Grießmann. "Electrical characterization of thick film materials." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2015, CICMT (September 1, 2015): 000079–84. http://dx.doi.org/10.4071/cicmt-tp23.
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The thick-film technology is one of the fundamental technologies for the production of circuit carriers for electronic modules. It is mainly used in areas with harsh environmental conditions, such as sensor or automotive applications. Basis of the thick film technology are glass-based pastes, which are screen printed on ceramic substrates and fired in a high temperature process at (500…1000) ° C. Such thick film pastes are commercially available from various suppliers as elements of paste systems, which mainly include compatible isolation, resistance and conductive pastes. There are a number of requirements according the fired thick film characteristics, such as high breakdown voltage of isolation thick films or low noise performances of resistance thick films. However, the most requirements are concentrating on conductor thick films. They should guarantee excellent properties in terms of assembling (soldering, bonding) which are focused in a many publications. Simultaneously, they should also offer very good electrical characteristics that have not been completely investigated until today. At Fraunhofer IKTS different measurement methods are developed and adapted to characterize the electrical performance of thick film structures. Already well known is the short term overload (STOL) measurement of thick film resistances, which determining the maximum power dissipation of the thick film structure. The basic concept of this measurement is adapted on conductive thick film structures like conductive tracks or vias. The investigations show correlations between geometrical thick film properties and the resulting thermal characteristics of the thick film structure. Results can be used to improve screen-printing layouts in terms of cost reduction (paste consumption) and thermal management (track width, via diameter), but can also help to improve paste compositions itself. The paper will give an overview of the used electrical measurement methods and present exemplary results.
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Shahbazi, Samson, Gregg Berube, Stephanie Edwards, Ryan Persons, and Caitlin Shahbazi. "High Performance Etchable RoHS Compliant Thick Film Gold Conductor." International Symposium on Microelectronics 2018, no. 1 (October 1, 2018): 000620–27. http://dx.doi.org/10.4071/2380-4505-2018.1.000620.
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Abstract The thick film paste manufacturers are expected to produce conductors which are lead and cadmium free, yet have excellent fired film properties and the same performance and properties as the cadmium and lead containing formulations. The fired film surface of these conductors must be defect free (i.e. imperfections, pills, agglomerates) after multiple firing steps and must perform on dielectric as well as substrates from different suppliers. Typically, the thick film gold conductors are used in high reliability applications such as medical devices, military applications, and high frequency circuits, which require robust performance at high and low temperatures, in chemically aggressive environments, or extremely humid conditions. As circuits decrease in size and become more complex, the thick film gold properties become increasingly critical. The challenge is to develop an alternative gold conductor formulation, which can print and resolve fine features (down to 4 mil lines and spaces) as well as have the ability to be etched for higher density circuit designs (down to 1–2 mil lines and spaces). Gold conductors are typically used in conjunction with other high temperature thick films so good performance after multiple firings was also a targeted requirement. Heraeus has been proactive for the past decade in the development of thick film products that are both RoHS (lead and cadmium free) as well as REACH compliant. This paper discusses the experiments that were performed in order to understand the contribution of gold powder, organic and inorganic system to improve the fired film performance. These formulations were compared against existing gold conductors including the high performance gold conductor options as well as other available standard gold conductor options. Thin wire bonding trials including both gold and aluminum wire are used to compare influences of raw materials which includes high volume wire bonding reliability including failure modes and aged wire bond adhesion at elevated temperature exposures (300°C) for extended periods of time. In order to analyze fired film morphology and link this up to wire bond performance, SEM images of the conductor surface and cross sections were conducted. These studies resulted in a newly developed thick film gold conductor paste for use in a wide variety of applications. We present wire-bonding data with gold and aluminum wire and reliability results on both 96% Al2O3 ceramic substrates as well as on top of standard dielectrics.
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Reimann, T., J. Töpfer, and S. Barth. "Low-temperature sintered NTC ceramics for thick film temperature sensors." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2012, CICMT (September 1, 2012): 000536–41. http://dx.doi.org/10.4071/cicmt-2012-wp42.
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Printed thick film NTC thermistors and multilayer devices are frequently used for temperature control in hybrid circuits. NiMn2O4 and substituted spinels are the most established materials for this application. For low-temperature sintering at 900 °C the shrinkage behavior of the thermistor material has to be adjusted by the addition of proper sinter additives. We investigated the chemical stability of NiMn2O4 and substituted spinels in air between 25 °C and 1200 °C. The compound NiMn2O4 is stable from 700 °C to 970 °C only and interacts with the sinter additives. Stable cubic spinels were found in the system ZnxNi0,5Co0,5Mn2-zO4. Addition of liquid phase sintering additives to the spinel powders results in complete densification at 900 °C. No chemical interaction between spinel and additive was observed. The effect of Cu-substitution into the spinel was also investigated. Functional NTC pastes were printed on alumina substrates and post-fired at 900 °C. The NTC thermistor films have a sheet resistivity of about 300 kOhm/sq and B = 3300 K. The firing behavior, microstructure formation and electric properties of NTC thick films will be reported.
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Gruber, Patric A., Eduard Arzt, and Ralph Spolenak. "Brittle-to-ductile transition in ultrathin Ta/Cu film systems." Journal of Materials Research 24, no. 6 (June 2009): 1906–18. http://dx.doi.org/10.1557/jmr.2009.0252.
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Current semiconductor technology demands the use of compliant substrates for flexible integrated circuits. However, the maximum total strain of such devices is often limited by the extensibility of the metallic components. Although cracking in thin films is extensively studied theoretically, little experimental work has been carried out thus far. Here, we present a systematic study of the cracking behavior of 34- to 506-nm-thick Cu films on polyamide with 3.5-to 19-nm-thick Ta interlayers. The film systems have been investigated by a synchrotron-based tensile testing technique and in situ tensile tests in a scanning electron microscope. By relating the energy release during cracking obtained from the stress-strain curves to the crack area, the fracture toughness of the Cu films can be obtained. It increases with Cu film thickness and decreases with increasing Ta film thickness. Films thinner than 70 nm exhibit brittle fracture, indicating an increasing inherent brittleness of the Cu films.
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Wang, John, and Yu Zhang. "Nanostructured Mesoporous Thick Films of Titania for Dye-Sensitized Solar Cells." Applied Mechanics and Materials 110-116 (October 2011): 540–46. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.540.
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For energy harvesting, such as in dye-sensitized solar cells, thick films of nanostructured mesoporous titania are inevitably required. Although various mesoporous thin films, i.e., film thickness below 300 nm, such as those of TiO2 and SiO2, have been widely investigated via a supramolecular templating approach in the past decade, little progress has been made with thick films, i.e., film thickness of at least several micrometers. In order to develop the desperately wanted thick films of mesoporous nanostructure for titania, we have successfully modified the supramolecular templating approach, where the highly crystallized mesoporous titania thick films of varying thicknesses and different morphologies are realized, resulting in the formation of highly ordered body-centered orthorhombic and disordered wormlike mesostructures. The performance of these mesoporous films in dye-sensitized solar cells has been investigated, achieving a maximum efficiency of ~7% at the film thickness of ~6 μm. The highly ordered mesoporous titania film outperforms the disordered counterpart of the same thickness in both short circuit current and efficiency. The improved cell performance of the ordered mesoporous film is shown to arise from the enhanced electron transport in the regularly packed titania network due to the enhanced crystalline grain connectivity.
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Yasir, Muhammad, Pietro Zaccagnini, Gianluca Palmara, Francesca Frascella, Niccolò Paccotti, and Patrizia Savi. "Morphological Characterization and Lumped Element Model of Graphene and Biochar Thick Films." C 7, no. 2 (March 27, 2021): 36. http://dx.doi.org/10.3390/c7020036.
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Carbon based materials exhibit interesting mechanical, thermal and electrical properties which make them excellent contenders for use as fillers in composites as film. Graphene has been vastly used among the carbon-based materials. More recently eco-friendly carbon-based materials like biochar have emerged. The deployment of carbon-based materials in films needs to be studied since films are more versatile and permit the exploitation of electrical properties of such materials over circuits and systems. Typical circuits and systems exploiting electrical properties of novel materials perform a number of applications including sensing, detection, tunable devices and energy harvesting. In this paper, films composed of 9:1 graphene or biochar are deployed on a microstrip line. The morphological properties of graphene and biochar and their respective films are studied with Raman spectra and Field Emission Scanning Electron Microscope (FESEM). The electrical properties (four-point probe measurements and scattering parameter measurements) of the films. Low frequency measurements are used as starting point for circuit models estimating the lumped impedance of the films. From the morphological characterization it is shown that biochar films appear as granulates carbonaceous materials whereas graphene films contains several flakes forming a network. From the low frequency measurements and microwave characterization it is seen that graphene films are more conductive as compared to biochar films. In many applications, it is useful to know the surface impedance of the film since it varies on interaction with any external stimulus (variation of pressure, humidity, gas, etc.).
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Puri, V. "Performance Enhancement of Thick Film Microstripline Circuits by Metallic Thin Film Overcoat." Microelectronics International 11, no. 2 (February 1994): 28–30. http://dx.doi.org/10.1108/eb044530.
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Peng, Shanglong, Desheng Wang, Fuhua Yang, Zhanguo Wang, and Fei Ma. "Grown Low-Temperature Microcrystalline Silicon Thin Film by VHF PECVD for Thin Films Solar Cell." Journal of Nanomaterials 2015 (2015): 1–5. http://dx.doi.org/10.1155/2015/327596.
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Hydrogenated microcrystalline silicon thin films can be used to fabricate stable thin film solar cell, which were deposited by very high frequency plasma-enhanced chemical vapor deposition at low temperatures (~200°C). It has been found that the obtained film presented excellent structural and electrical properties, such as high growth rate and good crystallinity. With the decreasing of silane concentration, the optical gap and the dark conductivity increased, whereas the activation energy decreased. A reasonable explanation was presented to elucidate these phenomena. In addition, we fabricated p-i-n structure solar cells using the optimum microcrystalline silicon thin films, and preliminary efficiency of 4.6% was obtained for 1 μm thick microcrystalline silicon thin film solar cells with open-circuits voltage of 0.773 V and short-circuits current density of 12.28 mA/cm2. Future scope for performance improvement lies mainly in further increasing the short-circuit current.
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Suh, Seigi, Ryan Persons, Doug Hargrove, and Gregory Berube. "Solderable Polymer Thick-film Conductors for Low Temperature Substrates." International Symposium on Microelectronics 2018, no. 1 (October 1, 2018): 000310–16. http://dx.doi.org/10.4071/2380-4505-2018.1.000310.
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Abstract For decades, polymer thick-film (PTF) systems have provided a low cost, non-fired option for screen-printing simple electronic circuits. The ability to apply these types of pastes on temperature sensitive substrates such as PET, polycarbonate, polyimide, and other polymers has facilitated a variety of applications, for instance membrane touch-switch keypads, buss bars for touch screens, various types of sensors, and flexible circuitry. Polymer thick-film is also one of the primary technology solutions utilized in the rapidly emerging Printed Electronic market, where flexible, durable materials are paramount to the success of these technologies. One of the largest emerging markets for polymer thick-film is wearable electronics, where engineers are designing “smart fabrics” with active circuitry for medical monitoring, performance enhancement in sports, and personal comfort. Polymer thick-film pastes include silver pastes for conductors, carbon pastes for resistive applications, silver-silver chloride fillers for glucose sensors, and dielectric pastes. The major challenge with PTF silver conductors is that they are not conducive to soldering. This hinders the ability to attach components, leads, dies, wires, or other features to the prints. As copper is solderable, one possible solution would be a copper polymer thick-film metallization; however they start oxidizing at the typical paste curing temperatures, 110 – 130°C, rendering them unsuitable for the vast majority of conductive applications. In order to meet these challenges, Heraeus has developed a new line of solderable polymer thick-film conductors based on a high-performance silver-coated copper conductive filler. These metallizations are solderable, resistant to solder leaching, and result in sheet resistivities approaching that of pure silver polymer conductors. The prints do not degrade in performance when cured at temperatures as high as 200°C. The new product line was formulated to accept different types of solders, especially traditional SAC-305, which provides a complete matched solution for designers. The new metallization opens up new applications given its ability to print polymer circuitry on a variety of substrates including aluminum, steel, FR4, Kapton, Mylar, and glass. The technology also allows for the fabrication of more complex circuitry on these types of substrates, giving circuit designers a powerful new tool in their toolbox in applications such as LED lighting, sensors, and heaters. Finally, these materials may provide a lower-cost option for solderable flexible polymer end terminations for components used in vibration sensitive applications, for instance the automotive industry. In our paper, we will present the properties of the new pastes and printed conductors. Performance testing includes surface resistivity, solderability, solder leach resistance, voiding, and adhesion on two substrates: FR4 and Kapton. Furthermore, we show that the solderable PTF conductor will provide a potential cost- savings over the current technology used on FR4 boards, stamped copper films. By replacing the stamped copper with our solderable PTF conductor, manufacturers will have the advantage of replacing a subtractive process for etching their patterns with an additive, environmentally friendly process, not only saving processing time but eliminating a large, dangerous copper waste stream. Finally, we will summarize the applications that the new technology enables.
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Löffler, Sebastian, Christopher Mauermann, Angela Rebs, and Günter Reppe. "Multilayer thick-film ceramic for multichip modules with laser microvias." Microelectronics International 35, no. 3 (July 2, 2018): 158–63. http://dx.doi.org/10.1108/mi-11-2017-0065.
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Purpose The purpose of the paper is to show up the current possibilities by combination of classic thick-film technology with advanced processing. Thick-film hybrid ceramic substrates have been a base for highly reliable devices for space, aerospace, medical and industrial applications since many years. The combination of classic thick-film printing with advanced technologies for fine line structuring provides substrates best suited for packaging solutions with challenging requirements, such as temperature stability and extended product lifetime. Combined with state of the art assembly technologies, thick-film substrates are used in highly demanding industries. Design/methodology/approach In recent years, several technologies for fine line structuring have been introduced, e.g. fine line printing, photo imaging, etching, laser structuring for local chip fan-out or fine line structuring on single layers. For further miniaturization of thick-film multilayers circuits, after solving the fine line resolution, the reduction of electrical connection of conductive layers through printed insulation/dielectric layer (via) diameters to connect the layers should be addressed. Findings The focus of this paper is to show the results of combining fine line structuring with laser microvias and to compare laser drilling in thick-films with different established via forming technologies. Originality/value The reduction of via size to 60 µm – smaller than 50% compared to using state-of-the-art printing technologies enables a solution for significant relaxation of current design possibilities.
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Beikmohamadi, Allan, Steve Stewart, Jim Parisi, Mark McCombs, Michael Smith, Ken Souders, J. C. Malerbi, K. M. Nair, Deepukumar Nair, and Michael Farb. "Electroplating and Electroless Plating Process Development for DuPont™ GreenTape™ 9K7 LTCC." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2013, CICMT (September 1, 2013): 000283–87. http://dx.doi.org/10.4071/cicmt-tha45.
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Low Temperature Co-fired Ceramic (LTCC) technology provides an attractive packaging platform for microwave and millimeter wave circuits and systems due to its unique properties. Generally, thick film gold or silver conductors are used as metallizations on LTCC substrates along with occasional use of copper thick films. This paper reports methods and results of extensive process development experiments DuPont Microcircuit Materials has undertaken to establish a commercially viable plating process for the market leading DuPont™ GreenTape™ 9K7 LTCC system. Both Electroplating and Electroless plating processes are investigated in this work. These techniques provide certain advantages when used in isolation or in combination with standard thick film metallizations, helping to extend their applicability. Electroplating of copper on LTCC provides a means of using copper as the external conductor without having to use complicated firing processes in oxygen-free atmosphere as required for copper thick film. This approach leads to a much more cost effective approach if copper is required as the external metal. Electroless Nickel/Gold plating (ENIG) of both silver and copper (electroplated and/or thick film) provides an industry standard, highly reliable, robust surface finish. Such surface finish enables easy integration of both soldering and wire bonding processes.
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Lee, Hoontaek, Kumjae Shin, and Wonkyu Moon. "Capacitive Measurements of SiO2 Films of Different Thicknesses Using a MOSFET-Based SPM Probe." Sensors 21, no. 12 (June 13, 2021): 4073. http://dx.doi.org/10.3390/s21124073.
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We utilized scanning probe microscopy (SPM) based on a metal-oxide-silicon field-effect transistor (MOSFET) to image interdigitated electrodes covered with oxide films that were several hundred nanometers in thickness. The signal varied depending on the thickness of the silicon dioxide film covering the electrodes. We deposited a 400- or 500-nm-thick silicon dioxide film on each sample electrode. Thick oxide films are difficult to analyze using conventional probes because of their low capacitance. In addition, we evaluated linearity and performed frequency response measurements; the measured frequency response reflected the electrical characteristics of the system, including the MOSFET, conductive tip, and local sample area. Our technique facilitated analysis of the passivation layers of integrated circuits, especially those of the back-end-of-line (BEOL) process, and can be used for subsurface imaging of various dielectric layers.
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Lakeman, Charles D. E., and Patrick F. Fleig. "High‐resolution integration of passives using micro‐contact printing (μCP)." Microelectronics International 20, no. 1 (April 1, 2003): 52–55. http://dx.doi.org/10.1108/13565360310455544.
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As the number of passive components in electronic circuits increases, new methods for fabricating passives are under development to optimize utilization of board space. In this paper, we will describe the performance capabilities of TPL's micro‐contact printing (μCP) process to fabricate near‐net‐shape structures with feature sizes ranging from 100 microns to the sub‐micron scale. Like thick film processes, this novel process is compatible with a broad materials base, making a large range of materials properties available. Unlike thick film, however, this novel process employs powder‐free inks that can be patterned with high resolution. It is anticipated that this process will enable integration of passive components that show thin film performance at thick film cost. Emphasis in this paper will be placed on processing conditions, and materials properties to demonstrate the feasibility of this process for passive device fabrication.
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Choe, JoonWon, Jesus Noel Calat, and Guo-Quan Lu. "Constrained-film sintering of a gold circuit paste." Journal of Materials Research 10, no. 4 (April 1995): 986–94. http://dx.doi.org/10.1557/jmr.1995.0986.
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We studied the constrained-film sintering of a gold circuit paste used in microelectronic packaging applications. Optical techniques were developed to determine the shrinkage profiles of constrained and free films and stresses generated during sintering in the constrained films. Constrained films approximately 60 μm thick were made by multiple screen-printing of the gold paste on rigid alumina substrates, while the free films were obtained by peeling off portions of the gold films from the substrate after binder burnout. Constrained films for stress measurement were made by multiple screen-printing on an oxidized 25 μm thick silicon substrate. Sintering runs were done in a hot stage at temperatures between 650 °C and 900 °C. The densification rates were much lower in the constrained films than those in the free films. The in-plane tensile stresses in the constrained films, determined by wafer curvature measurement, rose rapidly to a maximum level of 510 kPa during the initial stage of sintering and then gradually decreased. The reduction in the sintering potential due to the hydrostatic stress is not large enough to completely account for the retarded densification in constrained films. SEM micrographs of the film microstructures after sintering showed no-significant difference in grain growth kinetics between the constrained and free films. However, the activation energy for densification was found to be very different between the two types of films, 90.1 ± 4.3 kJ/mole for the free film and 188.8 ± 6.7 kJ/mole for the constrained film. We suggest that the retarded densification kinetics in the constrained gold films is due to (i) the reduction in the sintering potential by the hydrostatic stress and (ii) a change in the dominant sintering mechanism from grain-boundary diffusion in the free films to lattice diffusion in the constrained films.
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Telnikov, Ye Ya, O. G. Chernyshyn, O. M. Nedbailo, and I. O. Khmara. "Structure and mechanism of electrical conductivity of resistive compositions for thick-film metal-ceramic heating elements." Кераміка: наука і життя, no. 2(43) (July 7, 2019): 23–28. http://dx.doi.org/10.26909/csl.2.2019.4.
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The work is devoted to the solution of scientific and technical problems of creating granular resistive thick films used in the manufacture of metal-ceramic heating elements. Using the method of mechanosynthesis, particles of transition metal borides and aluminoborosilicate glass of complex chemical composition were obtained.
The electrical and thermal properties of thick-film metal-ceramic heating elements with a resistive layer based on modified particles of a conductive material are studied.
The heating elements of the new generation are made by the method of thick-film technology, which is widely used in microelectronics in the manufacture of hybrid electronic circuits. Structurally, the thick-film heater is a base (metal with a dielectric coating, ceramics, glass, glass), which is consistently applied through a mesh stencil resistive paste and a dielectric protective coating.
Direct heat transfer from the heating film to the substrate of the heat remover, due to the very low thermal inertia of the design, provides a quick exit of the heating element to the operating temperature. This feature of heaters opens new opportunities for their special use.
The resistive layer is a complex heterogeneous disordered system containing regions with a metallic conductivity and dielectric portions. The electrical conductivity in such systems is a superposition of the metallic type — in the conducting phase and the activation phase — through the interlayer between the particles. The layer plays the role of a potential barrier for current carriers and largely determines the predominance of one of the electromigration mechanisms. Its composition and properties are formed during the interaction of molten glass with oxide films of particles of the conductive phase and doping of the compositions.
Obtaining composite particles of the conductive phase in the process of preparation and heat treatment of materials allows you to purposefully change the properties of the nanoscale interlayer between these particles, which leads to the possibility of creating a group of materials and heating elements based on them with a complex of new properties.
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Ishida, Akira, and Morio Sato. "Development of Polyimide/SMA Thin-Film Actuator." Materials Science Forum 654-656 (June 2010): 2075–78. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.2075.
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Ti-Ni-Cu shape memory alloy (SMA) thin films were sputter-deposited on heated polyimide substrates. The (Ni,Cu) rich Ti-Ni-Cu films deposited at a substrate temperature of 543 K were found to possess a high martensitic transformation temperature above room temperature over a wide range of Cu content from 7 to 23 at%, which allows stable production of actuators that operate at room temperature. Additional deposition of a Cu film onto the Ti-Ni-Cu films facilitated the soldering of wires onto the actuators and also decreased the power consumption and response time of the actuator. The force of a polyimide/Ti-Ni-Cu SMA actuator could be increased merely by increasing the thickness of the polyimide film. An actuator composed of a 125 m thick polyimide film and an 8 m thick TiNiCu film was able to lift a 13.5 g weight. Furthermore, a Ti-Ni-Cu film could be pattern etched on a polyimide film to produce a circuit. The results indicate that a polyimide/SMA film actuator is a promising simple actuator that can be produced by simply cutting out an appropriately shaped piece with scissors or by punching and then connecting the two edges to a battery by soldering.
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Shi, Qiang, Jun Bo Wang, De Yong Chen, and Yan Long Shang. "A Flush-Mounted Resonant Ice Detection Sensor with High Sensitivity." Key Engineering Materials 503 (February 2012): 81–86. http://dx.doi.org/10.4028/www.scientific.net/kem.503.81.
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An ice detection system consisting of a resonant piezoelectric sensing-element and closed-loop circuit has been developed to automatically and distinctly sense ice films up to 1.3 mm thick. Accretion of ice and/or water on the sensor surface modifies the effective mass and/or stiffness of the vibrating transducer; these variations are sensed by measuring the changes in transducer resonant frequency. In case of ice films, resonant frequency of the transducer increases steadily from 60.9 kHz with no ice to 131.5 kHz when the ice film is 1.3mm thick. The time and temperature stability experiments revealed frequency variety no more than 1 kHz. The resolution of this sensor is better than 0.06mm.
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Choi, Jong Jin, Joo Hee Jang, Dong Soo Park, Byung Dong Hahn, Woon Ha Yoon, and Chan Park. "Electrical Properties of Lead Zinc Niobate - Lead Zirconate Titanate Thick Films Formed by Aerosol Deposition Process." Solid State Phenomena 124-126 (June 2007): 169–72. http://dx.doi.org/10.4028/www.scientific.net/ssp.124-126.169.
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Lead zinc niobate (PZN) added lead zirconate titanate (PZT) thick films with thickness of 5~10 μm were fabricated on silicon and sapphire substrates using aerosol deposition method. The contents of PZN were varied from 0, 20 and 40 %. The as deposited film had fairly dense microstructure without any crack, and showed only a perovskite single phase formed with nano-sized grains. The as-deposited films on silicon were annealed at temperatures of 700oC, and the films deposited on sapphire were annealed at 900oC in the electrical furnace. The effects of PZN addition on the microstructural evolution were observed using FE-SEM and HR-TEM, and dielectric and ferroelectric properties of the films were characterized using impedance analyzer and Sawyer-Tower circuit, respectively. The PZN added PZT film showed poor electrical properties than pure PZT film when the films were coated on silicon substrate and annealed at 700oC, on the other hand, the PZN added PZT film showed higher remanent polarization and dielectric constant values then pure PZT film when the films were coated on sapphire and annealed at 900oC. The ferroelectric and dielectric characteristics of 20% PZN added PZT films annealed at 900oC were comparable with the values obtained from bulk ceramic specimen with same composition sintered at 1200oC.
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Clemens, Bruce M., and Robert Sinclair. "Metastable Phase Formation in Thin Films and Multilayers." MRS Bulletin 15, no. 2 (February 1990): 19–28. http://dx.doi.org/10.1557/s0883769400060425.
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It is well known that thin-film technology relies increasingly on multilayered structures. As dimensions become smaller, the interfacial or contact region assumes a larger and often dominant role in the performance or properties. Many examples come readily to mind. In magnetic hard disks, the active cobaltalloy layer, itself only about 50 nm thick, is grown either on a crystalline chromium thin film or directly onto amorphous nickel-phosphorous, and capped with a protective carbon or chromium-carbon coating (see Figure 1). The recording head “flies” at 90 mph and about 0.1 ü above this combination, which is expected to be mechanically durable and magnetically reliable for thousands of recordings. Atomic-scale multilayers are being investigated to provide the ability to “tune” the magnetic properties of the active recording layer or head materials. Exchange coupled magneto-optical media consisting of a few tens of angstroms of cobalt or nickel layers on amorphous TbFeCo alloys are showing promise for improving magneto-optical coupling while maintaining perpendicular anisotropy. In microelectronic circuits, aluminum or silicide contacts to silicon are essential to any device, and multilevel integration involving a series of metal, alloy, silicon (amorphous, poly- or monocrystalline) and dielectric layers (some of which might be 1-10 nm thick) are increasingly required to achieve large-scale integration. Metal-metalloid (e.g., MoSi, W-C) multilayers are used for x-ray optical elements. Artificially produced metallic superlattices and multilayers are being used to probe the fundamental magnetic, electronic, mechanical, and structural properties of metal-metal interfaces.
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Klimiec, Ewa, Wiesław Zaraska, Jacek Piekarski, and Barbara Jasiewicz. "PVDF Sensors – Research on Foot Pressure Distribution in Dynamic Conditions." Advances in Science and Technology 79 (September 2012): 94–99. http://dx.doi.org/10.4028/www.scientific.net/ast.79.94.
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The paper presents a dynamic measurement method of the distribution of foot pressure exerted on the ground by a four-point shoe insole, developed by authors, which can be placed in any sport footwear. The value of pressure was measured on the heel, medial midfoot, metatarsal, and great toe by recording values of a generated voltage by sensors which were made of piezoelectric polymer PVDF film 110 µm thick with printed silver electrodes. As confirmed by scanning microscope studies, the foil applied in the sensors is semi-crystalline. The shoe measurement insert consists of two polyester films without piezoelectric properties between them, electroactive polymer sensors were placed. The films were glued together. To match the measuring circuit to the sensors used, two circuits were tested, a voltage measuring circuit with an input resistance of above 1012 Ω (open circuit), and a charge measuring circuit (shorted circuit). The charge measuring circuits with the RC high-pass filter, which attenuates the slow-changing pyroelectric signal was selected as it ensures the desired measurement accuracy. As presented in the paper, as PVDF sensors are very sensitive to any mechanical deformation, it is important to properly design the shoe insole to ensure its correct use during pressure distribution measurements. The measuring system developed by the authors, allows testing of foot pathology for any length of time in a dynamic way.
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Al-Moathin, Ali, Lianping Hou, Afesomeh Ofiare, Jue Wang, Shengwei Ye, Chong Li, and John H. Marsh. "Thick film hydrogen silsesquioxane planarization for passive component technology associated with electronic-photonic integrated circuits." Journal of Vacuum Science & Technology B 37, no. 6 (November 2019): 061210. http://dx.doi.org/10.1116/1.5123286.
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Gradmann, Rena, Thomas Seuthe, Christian Vedder, Markus Eberstein, and Uwe Partsch. "Adaption of Functional Ceramic Materials for the Laser Sintering Process in Integrated Sensor Applications." Journal of Microelectronics and Electronic Packaging 13, no. 4 (October 1, 2016): 176–81. http://dx.doi.org/10.4071/imaps.515.
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The ceramic thick film technology allows the buildup of miniaturized and robust integrated multilayer circuits and sensors by means of sequential screen printing and firing of different functional materials. However, the manufacturing of integrated electronics does not succeed if the components are temperature sensitive or too large for the process in a sintering furnace. At present, large components like wind power rotors, axles, or roller bearings are monitored by vulnerable hybrid sensor systems. To implement the advantages of integrated devices, such as the direct surface contact and the high thermomechanical stability, functional ceramic-based materials are adapted or newly developed to accommodate the requirements of laser sintering techniques of printed sensor layers on structural components. In a first approach, first screen-printed thick films on steel components are investigated. The defect-free densification of functional layers crucially depends on the particular material composition and adapted laser treatment. A first generation of functional layers is presented, comprising insulating, conductive, and resistive electrical materials. The films are tested in demonstrator setups and show functional properties comparable with those of the furnace sintering technology. Herein, future aspects of material optimization and the adaption to specific application requirements are discussed.
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Kántor, Z. "Sub-picosecond excimer laser machining of a thick film circuit material." Thin Solid Films 453-454 (April 2004): 350–52. http://dx.doi.org/10.1016/j.tsf.2003.11.101.
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Thouless, M. D., J. Gupta, and J. M. E. Harper. "Stress development and relaxation in copper films during thermal cycling." Journal of Materials Research 8, no. 8 (August 1993): 1845–52. http://dx.doi.org/10.1557/jmr.1993.1845.
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The reliability of integrated-circuit wiring depends strongly on the development and relaxation of stresses that promote void and hillock formation. In this paper an analysis based on existing models of creep is presented that predicts the stresses developed in thin blanket films of copper on Si wafers subjected to thermal cycling. The results are portrayed on deformation-mechanism maps that identify the dominant mechanisms expected to operate during thermal cycling. These predictions are compared with temperature-ramped and isothermal stress measurements for a 1 μm-thick sputtered Cu film in the temperature range 25–450 °C. The models successfully predict both the rate of stress relaxation when the film is held at a constant temperature and the stress-temperature hysteresis generated during thermal cycling. For 1 μm-thick Cu films cycled in the temperature range 25–450 °C, the deformation maps indicate that grain-boundary diffusion controls the stress relief at higher temperatures (>300 °C) when only a low stress can be sustained in the films, power-law creep is important at intermediate temperatures and determines the maximum compressive stress, and that if yield by dislocation glide (low-temperature plasticity) occurs, it will do so only at the lowest temperatures (<100 °C). This last mechanism did not appear to be operating in the film studied for this project.
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Gradmann, Rena, Thomas Seuthe, Christian Vedder, Markus Eberstein, and Uwe Partsch. "Adaption of Functional Ceramic Materials for the Laser Sintering Process in Integrated Sensor Applications." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2016, CICMT (May 1, 2016): 000011–17. http://dx.doi.org/10.4071/2016cicmt-ta14.
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Abstract The ceramic thick-film technology allows the build-up of miniaturised and robust integrated multilayer-circuits and sensors by means of sequential screen-printing and firing of different functional materials. However, the manufacturing of integrated electronics does not succeed if the components are temperature sensitive or too large for the process in a sintering furnace. At present, large components like wind power rotors, axles or roller bearings are monitored by vulnerable hybrid sensor systems. In order to implement the advantages of integrated devices, like the direct surface contact and the high thermomechanical stability, functional ceramic-based materials are adapted or newly developed to accommodate the needs of laser sintering techniques of printed sensor layers on structural components. In a first approach, screen printed thick films on steel components are investigated. The defect-free densification of functional layers crucially depends on the particular material composition in combination with adapted laser treatment. A first generation of functional layers is presented, comprising isolating, conductive, and resistive electrical materials. The films are tested in demonstrator setups and show functional properties comparable to those of the furnace sintering technology. Future aspects of material optimization and the adaption to specific application requirements will be discussed.
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Moberly, Warren J., Daniel Schwarcz, and Milton Ohring. "“dual phase” thin films prepared by deposition of aluminum on liquid nucleant gallium layers." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1432–33. http://dx.doi.org/10.1017/s0424820100131796.
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Aluminum thin films have been universally employed as interconnections in integrated circuits for the last quarter of a century. However, during this time Al metallization has never been totally immune from assorted reliability problems. This present research involves preparation and characterization of “dual phase” thin films, comprised of Al (or a transition metal) vacuum evaporated onto a liquid Ga (or other low melting temperature metal) nucleant layer. Ga is well known for causing grain boundary embrittlement in structural Al alloys. However, the Ga may well enhance the mechanical properties in Al thin films used as interconnect metallization, where this “dual phase” microstructure will prevent the buildup of stress that has historically resulted in electromigration failures in semiconductor devices. In addition, the presence of a liquid nucleant layer results in thin films (up to 2 μm thick) having surface roughness of the order of the film thickness, which in turn would enhance the bondability of such films.
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Zhang, Ji-Guang, David K. Benson, Edwin C. Tracy, and Satyen K. Deb. "The influence of microstructure on the electrochromic properties of LixWO3 films: Part II. Limiting mechanisms in coloring and bleaching processes." Journal of Materials Research 8, no. 10 (October 1993): 2657–67. http://dx.doi.org/10.1557/jmr.1993.2657.
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Various factors affecting the coloring and bleaching processes of LixWO3 films have been studied. The rate of the coloring process is limited by the decreasing electromotive force in the LixWO3 film and by the components of the series circuit resistance, including the electrolyte resistance and the diffusion impedance within the film. The bleaching process in a thick film is limited by either the space charge or by the diffusion impedance, depending on the experimental conditions. A more complete and quantitative model of the coloring/bleaching process has been developed and shows good agreement with experimental results. Our analysis also indicates that the lithium concentration value of x near the LixWO3/electrolyte interface can greatly exceed its reversible limit during the coloring process, even though the average x value within the film remains much lower than the reversible limit. This phenomenon may introduce some irreversible structural changes in the film, which in turn may constitute one of the film's degradation mechanisms.
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Prachopchok, P., Chanchana Thanachayanont, K. Sriprapha, A. Heawchin, S. Kaewket, P. Vijitjanya, C. Sac-Kung, and Tanakorn Osotchan. "Effect of Annealing on Material Properties of Both Electrodes in Dye Sensitized Solar Cell Structure." Advanced Materials Research 93-94 (January 2010): 587–90. http://dx.doi.org/10.4028/www.scientific.net/amr.93-94.587.
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In dye sensitized solar cell structure, the transparent electrodes of tin oxide doped fluorine (SnO2:F) was coated by titanium dioxide (TiO2) and platinum (Pt) for cathode and anode electrodes, respectively. In order to achieve high efficiency solar cell, both electrodes are required to have proper crystal structure size and morphology. These can be modified during the annealing process therefore the effects of electrode annealing on their crystal structure and surface modification were investigated in this study. Thick films of TiO2 and Pt were deposited by screen printing method on 3mm thick glass substrate (Nippon Sheet Glass) coated with 500nm thick SnO2:F. The glass substrate has sheet resistance of 20 ohm/square with the optical transmission of about 70%. The mixed TiO2 powder has the diameter of about 20 nm. The screen print structure was heated for drying in the oven at 150oC for 1 hour. Then the TiO2 thick films were annealed at various temperatures from 400 to 550oC for 2 hours, while the Pt films were annealed at lower temperature from 300 to 500oC. The obtained thickness of TiO2 and Pt film after annealing become about 10 and 3 µm, respectively. The crystallinity of the films was examined by x-ray diffraction while the surface morphology of both films was determined by atom force microscopy. To investigate the relation between material structure and the performance of the solar cell, the annealed electrodes at different temperature were used to fabricate the dye sensitized solar cell structure with standard rutherium(II) (N719) dye and then the current voltage characteristic was measured under light with air mass of 1.5. It found that the structure with higher anneal temperature electrode exhibited higher power conversion efficiency originating from the higher short circuit current density of better crystallinity and higher surface area.
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Feng, Guo-Hua, and Kuan-Yi Lee. "Hydrothermally synthesized PZT film grown in highly concentrated KOH solution with large electromechanical coupling coefficient for resonator." Royal Society Open Science 4, no. 12 (December 2017): 171363. http://dx.doi.org/10.1098/rsos.171363.
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This paper presents a study of lead zirconate titanate (PZT) films hydrothermally grown on a dome-shaped titanium diaphragm. Few articles in the literature address the implementation of hydrothermal PZT films on curved-diaphragm substrates for resonators. In this study, a 50-μm-thick titanium sheet is embossed using balls of designed dimensions to shape a dome-shaped cavity array. Through single-process hydrothermal synthesis, PZT films are grown on both sides of the processed titanium diaphragm with good adhesion and uniformity. The hydrothermal synthesis process involves a high concentration of potassium hydroxide solution and excess amounts of lead acetate and zirconium oxychloride octahydrate. Varied deposition times and temperatures of PZT films are investigated. The grown films are characterized by X-ray diffraction and scanning electron microscopy. The 10-μm-thick PZT dome-shaped resonators with 60- and 20-μm-thick supporting layers are implemented and further tested. Results for both resonators indicate that large electromechanical coupling coefficients and a series resonance of 95 MHz from 14 MHz can be attained. The device is connected to a complementary metal–oxide–semiconductor integrated circuit for analysis of oscillator applications. The oscillator reaches a Q value of 6300 in air. The resonator exhibits a better sensing stability when loaded with water when compared with air.
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Arsova, Irena, Abdurauf Prusi, Toma Grcev, and Ljubomir Arsov. "Electrochemical characterization of the passive films formed on niobium surfaces in H2SO4 solutions." Journal of the Serbian Chemical Society 71, no. 2 (2006): 177–87. http://dx.doi.org/10.2298/jsc0602177a.
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The electrochemical formation and characteristics of passive films on niobium surfaces in aqueous H2SO4 solutions were studied using open circuit potential and cyclic voltammetry. In the potential region between -1.0 and 1.2 V(NHE), the cyclic voltammetry data showed that the active/passive transition involves slow metal dissolution followed by the formation of semiconducting passive oxide films. The possible electrochemical reactions and the change of the oxidation steps of some niobium oxides occurring in the passive film during the polarization are proposed. A strong influence of the natural air-formed oxide film on the chemical composition of the passive film was shown. This influence makes chemical structure of thin passive films more complicated than that of thick anodic films. It is shown that the passive films consists of more or less stable oxides, such as NbO, NbO2 and Nb2O5. The Raman spectra revealed that the thin passive films were amorphous, while the films formed at higher voltages consist, primarily, of well-crystallized Nb2O5.
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Wu, Aiying, P. M. Vilarinho, A. I. Kingon, and I. Reaney. "Microstructural Characterization of Thick PZT films on Cu Foils Deposited by Electrophoresis." Microscopy and Microanalysis 14, S3 (September 2008): 23–26. http://dx.doi.org/10.1017/s1431927608089277.
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Piezoelectric and electrostrictive responses in poled and unpoled ferroelectric and relaxor ferroelectric compositions are of importance in transducers for converting electrical to mechanical impulses and vice-versa. Sensor applications make use of the very high piezoelectric constant dijk of the converse effect, which also permit efficient conversion of electrical to mechanical response. One of the most important families of materials for piezoelectric applications is Pb(Zr,Ti)O3(PZT). The most widely studied composition of PZT lies at the boundary between the tetragonal and rhombohedral phases, known as the morphotropic phase boundary (MPB) and exhibits greatly enhanced dielectric and piezoelectric properties in bulk and thin film. In modern electronic applications, pyroelectric detectors, piezoelectric microsensors, and micromechanical pumps require the integration of PZT films into a variety of device structures. To get sufficiently large piezoelectric strains for optimization of the performance and reliability of the device, thick films in the thickness range of 5–50 μm are desired. On the other hand burying the device components within the substrate is of utmost importance for miniaturization. In comparison to traditional surface mounted components embedded ones will free surface space for a higher functionality of the device, reduce solder points and increase device reliability. Additionally, to reduce the device costs the use of flexible copper foil as substrates is of particular interest. Its high conductivity and compatibility with printed circuit boards makes copper an attractive candidate substrate for embedded application. However, depositing PZT thick films on copper is not trivial, due to the conflict between the high temperature required to sinter PZT (∼1150°C) and low melting temperature of Cu (∼1050°C), in addition to the easy oxidation of Cu. As a consequence the preparation of PZT thick films on Cu involves a complex route to decrease the ceramic sintering temperature and to control the oxygen partial pressure. So far, no successful deposition of PZT thick films on copper foils was reported.
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Lakhtakia, A., R. Messier, V. V. Varadan, and V. K. Varadan. "Incommensurate Numbers, Continued Fractions, and Fractal Immittances." Zeitschrift für Naturforschung A 43, no. 11 (November 1, 1988): 943–55. http://dx.doi.org/10.1515/zna-1988-1106.
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Abstract Continued fractions have a rich tradition in the theory of numbers; e.g., non-terminating con tinued fractions represent irrational numbers. It will be shown that a class of continued fractions possess the property of self-referential decomposition, and their interpretation in the form of non-terminating ladder circuits gives rise to fractal immittances with potential analogies to rough surfaces, thin cermet films, as well as to the internal void network structure of thick films.
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You, S. Z., Y. F. Long, Y. S. Xu, Z. Q. Zhu, Y. L. Shi, Z. S. Lai, Z. F. Li, W. Lu, and A. Z. Li. "Fabrication and characterization of thick porous silicon layers for rf circuits." Sensors and Actuators A: Physical 108, no. 1-3 (November 2003): 117–20. http://dx.doi.org/10.1016/j.sna.2003.06.004.
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Pina, J. C. P., Maria José Marques, J. M. M. dos Santos, and A. Morão Dias. "Stress and Texture Analysis in Thin Films and Coatings by X-Ray Diffraction." Materials Science Forum 514-516 (May 2006): 1613–17. http://dx.doi.org/10.4028/www.scientific.net/msf.514-516.1613.
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The thin and textured coatings present a double difficulty for characterization by conventional X-ray diffraction. Their shallow depth reduces the diffracted intensity and allows the interference of the underlying material. Frequently they present a crystallographic texture which limits the number of orientations that provide good intensity and induces anisotropy effects on their mechanical behavior. Reliable results can be determined using diffraction geometry of lowincidence angle. This paper describes the application of the technique to several films, characterized by thicknesses of the order of 1 μm and crystallographic textures. Examples are proposed of chromium films applied by PVD on molybdenum substrates, decorative electroplated coatings, and aluminum coatings used for interconnections in microelectronic circuits. The Cr films are 1.5 μm thick and exhibit a strong <100> fiber texture. The decorative coatings were studied both on the nickel undercoat and in the Cr top layer. Results are presented for chromium where tensile stresses and a <110> fiber texture were observed. The Al films are 1.0 μm thick. Some samples were heattreated at different annealing temperatures. Tensile stresses were always observed, which increase in the annealed samples.
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Pedersen, U. P. I., O. Aaserud, and O. W. Bungum. "Combifilm: A Novel Thick‐ and Thin‐film Technology with Two Signal Layers for High‐speed Hybrid Circuits Signal Layers for High‐speed Hybrid Circuits." Microelectronics International 13, no. 1 (April 1996): 16–19. http://dx.doi.org/10.1108/13565369610800179.
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Lee, Hyunseop, Sukbae Joo, Hyoungjae Kim, and Haedo Jeong. "Chemical Mechanical Planarization Method for Thick Copper Films of Micro-Electro-Mechanical Systems and Integrated Circuits." Japanese Journal of Applied Physics 47, no. 7 (July 11, 2008): 5708–11. http://dx.doi.org/10.1143/jjap.47.5708.
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Steplewski, Wojciech, Andrzej Dziedzic, Janusz Borecki, Grazyna Koziol, and Tomasz Serzysko. "Environmental tests of embedded thin- and thick-film resistors in comparison to chip resistors." Circuit World 40, no. 1 (January 28, 2014): 7–12. http://dx.doi.org/10.1108/cw-10-2013-0039.
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Purpose – The purpose of this paper is to investigate the influence of parameters of embedded resistive elements manufacturing process as well as the influence of environmental factors on their electrical resistance. The investigations were made in comparison to the similar constructions of discrete chip resistors assembled to standard printed circuit boards (PCBs). Design/methodology/approach – The investigations were based on the thin-film resistors made of NiP alloy, thick-film resistors made of carbon or carbon-silver inks as well as chip resistors in 0402 and 0603 packages. The polymer thick-film resistive films were screen-printed on the several types finishing materials of contact terminations such as copper, silver, and gold. To determine the sensitivity of embedded resistors versus standard assembled chip resistors on environmental exposure, the climatic chamber was used. The measurements of resistance were carried out periodically during the tests, and after the exposure cycles. Findings – The results show that the change of electrical resistance of embedded resistors, in dependence of construction and base material, is different and mainly not exceed the range of 3 per cent. The achieved results in reference to thin-film resistors are comparable with results for standard chip resistors. However, the results that were obtained for thick-film resistors with Ag and Ni/Au contacts are similar. It was not found the big differences between resistors with and without conformal coating. Research limitations/implications – The studies show that embedded resistors can be used interchangeably with chip resistors. It allows to save the area on the surface of PCB, occupied by these passive elements, for assembly of active elements (ICs) and thus enable to miniaturization of electronic devices. But embedding of passive elements into PCB requires to tackle the effect of each forming process steps on the operational properties. Originality/value – The technique of passive elements embedding into PCB is generally known; however, there are no detailed reports on the impact of individual process steps and environmental conditions on the stability of their electrical resistance. The studies allow to understand the importance of each factor process and the mechanisms of operational properties changes depending on the used materials.
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Song, Jae-Sil, Yong Seob Park, and Nam-Hoon Kim. "Hydrophobic Anti-Reflective Coating of Plasma-Enhanced Chemical Vapor Deposited Diamond-Like Carbon Thin Films with Various Thicknesses for Dye-Sensitized Solar Cells." Applied Sciences 11, no. 1 (January 1, 2021): 358. http://dx.doi.org/10.3390/app11010358.
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Diamond-like carbon (DLC) thin films, prepared by a radio frequency plasma-enhanced chemical vapor deposition (PECVD) system, were investigated for application as an anti-reflective coating (ARC) for dye-sensitized solar cells (DSSCs) with a change in film thickness. The strength of the Raman spectrum, G-peak position, and ID/IG ratio, related to sp3 bonds in the DLC thin films, is directly attributed to some tribological properties including surface roughness, hardness, elastic modulus, friction coefficient, and contact angle. Some optical properties, such as transmittance, refractive index, and absorption coefficient, were examined after changing the thickness of DLC thin films. The optimal short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF) values were obtained for the significantly improved conversion efficiency (CE) from 4.92% to 5.35% in the 60 nm thick PECVD DLC ARC for DSSCs with hard and hydrophobic surfaces.
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Romig, A. D., D. R. Frear, and T. J. Headley. "High-spatial-resolution x-ray microanalysis of Al-2wt.% Cu aluminum thin films." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 216–17. http://dx.doi.org/10.1017/s0424820100153051.
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Aluminum - 2 wt.% copper alloys are commonly used in thin film form as interconnect metallization lines for integrated circuits. Experience has shown that the addition of the Cu to the Al, albeit at a decrease in conductivity, makes the metallizations more resistant to failure by electromigration. However, the mechanism by which Cu increases the resistance to electromigration has never been positively identified. One theory proposes that Cu coats the Al grain boundaries (boundaries are enriched in Cu) and retards grain boundary diffusion thereby reducing electromigration. Another theory suggests that a continuous thin layer of CuAl2 forms along the boundaries also reducing grain boundary transport and therefore the tendency to electromigrate. Recently, Frear et al. have reported on a detailed set of experiments to examine these theories from a microstructural viewpoint. Here, the details of the high spatial resolution microanalysis done to support the study of Fear, et al. are reported.Al- 2wt.% Cu was magnetron sputtered onto a borosilicate glass (BSG) coated (100) Si wafer. The Al-Cu films were sputtered at room temperature from a single source under an argon atmosphere at a deposition rate of 100 nm/min. Films 400 and 800 nm thick were prepared. The films were annealed under a 15% hydrogen forming gas (reducing) at 425°C for 35 min.
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Shen, Zhenzhen, Aleksey Reiderman, and Casey Anude. "Pressure-less AgNP Sintering for High-power MCM Assembly for Extreme Environment Applications." International Symposium on Microelectronics 2015, no. 1 (October 1, 2015): 000342–48. http://dx.doi.org/10.4071/isom-2015-wp14.
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Silver nano-particle (AgNP) sintering has been a promising bonding material for high-temperature applications. There is an increasing demand for designs implemented as multi-chip module (MCM) in the high-temperature markets, like the oil and gas industry, primarily because of MCM's smaller size, higher-performance capability, and higher overall reliability when compared to traditional high Tg printed circuit boards. In this work, pressure-less AgNP sintering paste was used in the assembly of multi-chip modules. The assemblies included die-mounted on aluminum nitride and alumina substrates that were metallized with various thin and thick films. Sintered silver nano-particle attachments were also attempted for surface-mounted technology (SMT) chip components. Different assembly parameters such as bonding line thickness and sintering profiles were evaluated to discover the optimal assembly process window that would yield acceptable reliability for 250°C and higher ambient temperature applications. The assemblies were subjected to various tests including thermal cycling, high-ramp rate thermal shocks, and high-temperature storage tests. Shear strength measurements and analysis of the cross sections and fracture surfaces were performed to understand failure mechanisms. One of the findings was a certain and unique failure mode associated with bonding of thin-film gold metallized surfaces using pressure-less silver nano-particles sintering. That failure mode begins after a short exposure to temperatures of 200°C and higher. However, silver nano-particle sintering on substrates metallized with thin-film silver and some thick-film formulations yields dramatically better results.
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David Theodore, N., Donald Y. C. Lie, J. H. Song, and Peter Crozier. "TEM study of phosphorus-implanted pseudomorphic Si0.88Ge0.12 on Si(100)." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 468–69. http://dx.doi.org/10.1017/s0424820100138713.
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SiGe is being extensively investigated for use in heterojunction bipolar-transistors (HBT) and high-speed integrated circuits. The material offers adjustable bandgaps, improved carrier mobilities over Si homostructures, and compatibility with Si-based integrated-circuit manufacturing. SiGe HBT performance can be improved by increasing the base-doping or by widening the base link-region by ion implantation. A problem that arises however is that implantation can enhance strain-relaxation of SiGe/Si.Furthermore, once misfit or threading dislocations result, the defects can give rise to recombination-generation in depletion regions of semiconductor devices. It is of relevance therefore to study the damage and anneal behavior of implanted SiGe layers. The present study investigates the microstructural behavior of phosphorus implanted pseudomorphic metastable Si0.88Ge0.12 films on silicon, exposed to various anneals.Metastable pseudomorphic Si0.88Ge0.12 films were grown ~265 nm thick on a silicon wafer by molecular-beam epitaxy. Pieces of this wafer were then implanted at room temperature with 100 keV phosphorus ions to a dose of 1.5×1015 cm-2.
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D. Dunn, Barrie, and Grazyna Mozdzen. "Tin oxide coverage on tin whisker surfaces, measurements and implications for electronic circuits." Soldering & Surface Mount Technology 26, no. 3 (May 27, 2014): 139–46. http://dx.doi.org/10.1108/ssmt-12-2013-0040.
Full textAbstract:
Purpose – This paper aims to evaluate the morphology and thickness of oxides that form on the surfaces of tin whiskers. The problems related to the growth of tin whiskers are stated, and the relevance of oxide layers adhering to whiskers is discussed. Design/methodology/approach – Modern laboratory methods including focused ion beam sectioning, energy dispersive spectroscopy and X-ray photoelectron spectroscopy have been used to characterise the composition of oxides present on the surfaces of 48-year-old whiskers. These very old whiskers had nucleated and grown on electronic equipment stored at ambient temperatures. They were compared to the oxide layers on newly grown 2-week-old whiskers. Findings – A dual oxide film, consisting of stannous and stannic oxides, was found present on both the old and the new whiskers. Measurements of oxide thickness were established for both generations of whiskers and these were noted to be similar to those films present on pure, cleaned bulk tin. Research limitations/implications – Only very new and very old whiskers, and their oxide films, were the focus of this investigation. However, sufficient data were gained to predict the effect both kinds of oxide films would have during whisker bridging between conductors and the risk of short circuits. Thick oxide films (order of 30 nm) may have a greater resistance to shorting, but they will be more difficult to remove during solder dipping (with respect to whisker mitigation). Practical implications – A knowledge of the oxide thickness on growing/gyrating tin whiskers will provide the electronics industry with data useful for establishing the risk of short circuits. It will also be useful during the forensic work associated with component and assembly failure analysis. Originality/value – The data resulting from this study are unique. They are of value to others who may require knowledge of the morphology, composition and thickness of oxides present on tin whiskers of different vintage.