Dissertations / Theses on the topic 'Adhesives Reliability'

The first part of the dissertation focuses on understanding and modeling the conduction mechanism of conductive adhesives. The contact resistance is measured between silver rods with different coating materials, and the relationship between tunnel resistivity and contact pressure is obtained based on the experimental results. Three dimensional microstructure models and resistor networks are built to simulate electrical conduction in conductive adhesives. The bulk resistivity of conductive adhesives is calculated from the computer-simulated model. The effects of the geometric properties of filler particles, such as size, shape and distribution, on electrical conductivity are studied by the method of factorial design. The second part of the dissertation evaluates the reliability and investigates the failure mechanism of conductive adhesives subjected to fatigue loading, moisture conditioning and drop impacts. In fatigue tests it is found that electrical conduction failure occurs prior to mechanical failure. The experimental data show that electrical fatigue life can be described well by the power law equation. The electrical failure of conductive adhesives in fatigue is due to the impaired epoxy-silver interfacial adhesion. Moisture uptake in conductive adhesives is measured after moisture conditioning and moisture recovery. The fatigue life of conductive adhesives is significantly shortened after moisture conditioning and moisture recovery. The moisture accelerates the debonding of silver flakes from epoxy resin, which results in a reduced fatigue life. Drop tests are performed on test vehicles with conductive adhesive joints. The electrical conduction failure happens at the same time as joint breakage. The drop failure life is found to be correlated with the strain energy caused by the drop impact, and a power law life model is proposed for drop tests. The fracture is found to be interfacial between the conductive adhesive joints and components/substrates. This research provides a comprehensive understanding of the conduction mechanism of conductive adhesives. The computer-simulated modeling approach presents a useful design tool for the conductive adhesive industry. The reliability tests and proposed failure mechanisms are helpful to prevent failure of conductive adhesives in electronic packages. Moreover, the fatigue and impact life models provide tools in product design and failure prediction of conductive adhesives.

Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2006.
Qu, Jianmin, Committee Chair ; Baldwin, Daniel, Committee Member ; Wong, C. P., Committee Member ; Sitaraman, Suresh, Committee Member ; Jacob, Karl, Committee Member.

Isotropically conductive adhesives (ICAs) are promising as a lead-free interconnect material; However, ICAs have a higher resistivity compared to tin/lead solder. The higher resistivity of ICAs results from the large contact resistance between conductive fillers. Several novel approaches to engineer the interface between electrically conductive fillers were studied to develop highly conductive ICAs. Shown in this dissertation are three methodologies to reduce contact resistance: low temperature sintering, fast sintering and in-situ reduction. Furthermore, two approaches, surface modification and in-situ protection, were developed to prevent oxidation and corrosion of silver-coated copper flakes to produce low cost ICAs. The findings and insights in this dissertation significantly contribute to (1) understanding of filler-filler, filler-polymer and structure-property relationships of ICAs; (2) the structural design and formulation of high performance ICAs; and (3) the wider use of ICAs in emerging applications such as printed electronics and solar cells.

Small form-factor packages with high integration density are driving the innovations in chip-to-package interconnections. Metallurgical interconnections have evolved from the conventional eutectic and lead-free solders to fine pitch copper pillars with lead-free solder cap. However, scaling down the bump pitch below 50-80µm and increasing the interconnect density with this approach creates a challenge in terms of accurate solder mask lithography and joint reliability with low stand-off heights. Going beyond the state of the art flip-chip interconnection technology to achieve ultra-fine bump pitch and high reliability requires a fundamentally- different approach towards highly functional and integrated systems. This research demonstrates a low-profile copper-to-copper interconnect material and process approach with less than 20µm total height using adhesive bonding at lower temperature than other state-of-the-art methods. The research focuses on: (1) exploring a novel solution for ultra-fine pitch (< 30µm) interconnections, (2) advanced materials and assembly process for copper-to-copper interconnections, and (3) design, fabrication and characterization of test vehicles for reliability and failure analysis of the interconnection. This research represents the first demonstration of ultra-fine pitch Cu-to-Cu interconnection below 200°C using non-conductive film (NCF) as an adhesive to achieve bonding between silicon die and organic substrate. The fabrication process optimization and characterization of copper bumps, NCF and build-up substrate was performed as a part of the study. The test vehicles were studied for mechanical reliability performance under unbiased highly accelerated stress test (U-HAST), high temperature storage (HTS) and thermal shock test (TST). This robust interconnect scheme was also shown to perform well with different die sizes, die thicknesses and with embedded dies. A simple and reliable, low-cost and low-temperature direct Cu-Cu bonding was demonstrated offering a potential solution for future flip chip packages as well as with chip-last embedded active devices in organic substrates.

Ce travail s'intègre dans les domaines de l'analyse et de la prédiction de la fiabilité des assemblages Multi-Chip Module. Il présente l'étude de fiabilité de microcâblages filaires (wire bonding) en très haute température à partir d'essais de vieillissement et d'analyses expérimentales. Les résultats permettent d'identifier les mécanismes de dégradation et d'évaluer les températures limites d'utilisation de ces interconnexions. Il développe une étude du comportement thermomécanique des joints collés à partir d'essais de caractérisation mécanique, d'essais de vieillissement accéléré et de simulations numériques par éléments finis. Ces méthodes permettent d'évaluer la criticité des assemblages dès la phase de conception
This work is performed in analysis and prediction areas of Multi-Chip Module package reliability. It presents a reliability study on wire bonding in high temperature environment from aging tests and experimental analyzes. Results permit to identify degradation mechanisms and evaluate temperature limits of these interconnections. It develops a study of the thermomechanical behavior of adhesive joints from mechanical characterization tests, accelerated aging tests and finite element simulations. These methods are used to assess the criticality of packages from the design phase

Three-dimensional (3D) integration of micro- and nano-electromechanical systems (MEMS/NEMS) with integrated circuits (ICs) is an emerging technology that offers great advantages over conventional state-of-the-art microelectronics. MEMS and NEMS are most commonly employed as sensor and actuator components that enable a vast array of functionalities typically not attainable by conventional ICs. 3D integration of NEMS and ICs also contributes to more compact device footprints, improves device performance, and lowers the power consumption. Therefore, 3D integration of NEMS and ICs has been proposed as a promising solution to the end of Moore’s law, i.e. the slowing advancement of complementary metal-oxide-semiconductor (CMOS) technology.In this Ph.D. thesis, I propose a comprehensive fabrication methodology for heterogeneous 3D integration of NEM devices directly on top of CMOS circuits. In heterogeneous integration, the NEMS and CMOS components are fully or partially fabricated on separate substrates and subsequently merged into one. This enables process flexibility for the NEMS components while maintaining full compatibility with standard CMOS fabrication. The first part of this thesis presents an adhesive wafer bonding method using ultra-thin intermediate bonding layers which is utilized for merging the NEMS components with the CMOS substrate. In the second part, a novel NEM switch concept is introduced and the performance of CMOS-integrated NEM switch circuits for logic and computation applications is discussed. The third part examines two different packaging approaches for integrated MEMS and NEMS devices with either hermetic vacuum cavities or low-cost glass lids for optical applications. Finally, a novel fabrication approach for through silicon vias (TSVs) by magnetic assembly is presented, which is used to establish an electrical connection from the packaged devices to the outside world.
Tredimensionell (3D) integration av mikro- och nano-elektromekaniska system (MEMS/NEMS) med integrerade kretsar (ICs) är en ny teknik som erbjuder stora fördelar jämfört med konventionell mikroelektronik. MEMS och NEMS används oftast som sensorer och aktuatorer då de möjliggör många funktioner som inte kan uppnås med vanliga ICs.3D-integration av NEMS och ICs bidrar även till mindre dimensioner, ökade prestanda och mindre energiförbrukning av elektriska komponenter. Den nuvarande tekniken för complementary metal-oxide-semicondictor (CMOS) närmar sig de fundamentala gränserna vilket drastiskt begränsar utvecklingsmöjligheten för mikroelektronik och medför slutet på Moores lag. Därför har 3D-integration identifierats som en lovande teknik för att kunna driva vidare utvecklingen för framtidens elektriska komponenter.I denna avhandling framläggs en omfattande fabrikationsmetodik för heterogen 3D-integration av NEMS ovanpå CMOS-kretsar. Heterogen integration betyder att både NEMS- och CMOS-komponenter byggs på separata substrat för att sedan förenas på ett enda substrat. Denna teknik tillåter full processfrihet för tillverkning av NEMS-komponenter och garanterar kompatibilitet med standardiserade CMOS-fabrikationsprocesser.I den första delen av avhandlingen beskrivs en metod för att sammanfoga två halvledarskivor med en extremt tunn adhesiv polymer. Denna metod demonstreras för 3D-integration av NEMS- och CMOS-komponenter. Den andra delen introducerar ett nytt koncept för NEM-switchar och dess användning i NEM-switch-baserade mikrodatorchip. Den tredje delen presenterar två olika inkapslingsmetoder för MEMS och NEMS. Den ena metoden fokuserar på hermetisk vakuuminkapsling medan den andra metoden beskriver en lågkostnadsstrategi för inkapsling av optiska komponenter. Slutligen i den fjärde delen presenteras en ny fabrikationsteknik för så kallade ”through silicon vias” (TSVs) baserad på magnetisk självmontering av nickeltråd på mikrometerskala.

20170519

碩士
健行科技大學
電機工程系碩士班
106
This study aims to explore the adhesives that can be applied in the field of optics. The adhesive materials have different characteristics, therefore, the adhesives jointly developed by the commercial or the commissioned manufacturers are selected as the research examples of the adhesives for optical component placement. Before the analysis, it is necessary to first analyze the characteristics of the material selected for the adhesive, and then find the reliable adhesive condition by the test. Then find reliable adhesive conditions by testing, use optical components to adhere to the optical system, and testify the reliability of different conditions. Through the measurement of the slight variation of the optical components in the optical system, the difference between the reliability test and the before and after is analyzed, and the offset under different loop measurement parameters is observed to select the reliability of the adhesive to meet the specifications of the optical system design. From the results of the characteristic data analysis of the adhesive, it is known that the effect of the offset of the curing shrinkage and the humidity in the reliability test is the largest, and the control of the curing shrinkage rate and the water absorption rate can improve the reliability of the optical system after assembly. The results of this study can be applied to a variety of assembly processes with precise requirements, such as optical system components, semiconductor wafer placement and optoelectronic components.

碩士
崑山科技大學
光電工程研究所
104
Reliability of GaN-Based LEDs affected by die-attach adhesive and leadframe was studied in this thesis. We have compared two die-attach adhesives, silver paste and epoxy. The thicknesses of silver paste were 10 μm and 30 μm.The thicknesses of epoxy were 5 μm, 10 μm and 30 μm. LED dies were attached on the plastic and the ceramic leadframes respectively with parameters of the die-attach adhesives described above.Evaluation items included die-shear strength, room temperature operating life test and thermal shock test. The results showed that the use of plastic or ceramic lead frame, the shear strength of epoxy is greater than that of silver paste at the same thickness of die-attach layer. According to the results of 1008 hrs room temperature life test, operating with 350 mA, the result showed that compared with the epoxy of die attach material, silver paste achieved a 12.7 % increase in light output, with 8℃ and 5.4℃/W decreases in junction temperature and thermal resistance at the same thickness of 10 μm in die-attach layer on plastic leadframe, respectively. Compared with the epoxy of die attach material, silver paste achieved a 4.4 % increase in light output , with 4.2℃ and 2.9℃/W decreases in junction temperature and thermal resistance at the same thickness of 30 μm in die-attach leadframe, respectively. The above results show that the silver paste has the better optical and thermal properties compared with epoxy in the same thinkness of die-attach layer. The die-attach layers of silver with the thickness 10 μm and 30 μm were compared. The result shown that the silver paste, on the plastic leadframe, with thickness of 10 μm has the better optical and thermal properties, with 37.4 % of light output power and 113.6℃ of junction temperature, 51.2℃/W of thermal resistance. Compared with the epoxy of die attach material, Silver Paste achieved a 6.5 % increase in light output, with 5.5℃and 7℃/W decreases in junction temperature and thermal resistance at the same thickness of 10 μm in die-attach layer on ceramic leadframe, respectively. Compared with the epoxy of die attach material, silver paste achieved a 6.9 % increase in light output but 10.8℃ and 9℃/W decreases in junction temperature and thermal resistance at the same thickness of 10 μm in die-attach layer on ceramic leadframe, respectively. The above results showed that the silver paste had better optical and thermal properties compared with epoxy in the same thickness of die-attach layer. Die-attach layers with the thickness 10 μm and 30 μm were compared. Silver paste with thickness of 10 μm has the better optical and thermal properties on the ceramic leadframe, with 64.3 % of light output power, 109.1℃ of junction temperature, 43.4℃/W of thermal properties. According to the 1000 cycles of thermal shock test, the result showed that the light output power has decreased to 70 % of the initial value of silver paste and epoxy with thickness of 30 μm on plastic or ceramic leadframe. The grouth of void wobserved in silver paste and the growth of crack was found in epoxy.

In the heating, ventilation, air conditioning and refrigeration (HVAC&R) industry, bonding and joining play an important role in the manufacturing and assembly process, which is critical to the cost, safety, reliability, and design freedom of systems. The goal of this thesis is to understand and evaluate the usage of adhesive bonds in the manufacture of HVAC&R systems, specifically in regards to leakage/reliability characterization and stress analysis under loading.

The bonding performance under static loading is first studied using a commercial epoxy adhesive product. In addition to the traditional surface preparation methods of mechanical and chemical etching, a novel laser-interference surface structuring preparation technique was utilized to improve bonding performance. Laser interference structuring uses a ND:YAG laser beam that is split into two beams that are re-directed to overlap on the same area of a copper alloy. A structuring pattern near the interference structuring limits is achieved due to the phase shift between the beams that is imparted as they are re-directed. Two different laser structuring methods were tested: spot-by-spot and laser raster. Different structuring parameters were varied including the laser spot size and pulses per spot (2, 4, 6, 8, 10, 12 pulses/spot) for the spot-by-spot method, and raster speed (2, 4, 6, 8, 10, 12 mm/s) for laser raster method. The microstructure morphology and surface profile after processing were characterized using the scanning electron microscopy (SEM) and profilometry for all surfaces. It was found that the laser-interference structuring removed the surface contaminants efficiently and formed dot- or net-shaped structures on the surface. This indicates that melting, vaporization, and solidification of the metal happened differently. Due to the much higher speed of the laser raster method, considering practical industrial applications, it is selected for additional investigation for shear strength improvement. The shear strength is measured by a single lap shear test which pulls apart adhesively bonded single lap joint specimen under shear loading using a mechanical tester.

Based on the surface profiles, three different laser raster speeds of 2 mm/s, 6 mm/s and 12 mm/s were selected for the manufacture of single lap joint specimens for comparison with the traditional surface preparation methods. The shear lap strength and displacement at maximum load were obtained for the specimens. The laser raster at 6 mm/s increased these values by approximately 11.0% and 25.1%, respectively, while the 12 mm/s condition had an increase of 16.8% and 43.8%, compared with the baseline traditional surface preparation method. It is concluded that laser structuring can enhance the single lap shear joint bonding performance. Within the tested laser processing parameters, a higher laser raster speed results in a larger enhancement.

In addition to the static loading test with epoxy adhesive, different adhesive formulations are investigated and developed by the collaborating adhesive manufacturer to determine their suitability for use under the temperature and pressure conditions in HVAC&R systems. Reliability, especially fatigue failure, is another major concern because the strength of the adhesive joints is sufficient for HVAC&R applications. Two primary types of fatigue may happen in practical applications: thermal fatigue and vibration fatigue. Two test facilities were designed and built to test the adhesive performance and understand the failure mechanisms. For the thermal fatigue testing, a novel pressure and temperature cyclic (PTC) test stand was designed to simulate the pressure and temperature changes that may occur in HVAC&R systems. The test stand was designed to switch between hot high-pressure gas and cold low-pressure gas by using a compressor with hot gas bypass setup. For the vibration testing, a standard industrial shaker was used to provide the required vibration at a given displacement and frequency with a specially designed fixture for the tested joints. In both tests, adhesive joints were tested in parallel with brazed joints, undergoing extreme thermal and vibration loading conditions. All the samples were leak-checked before and after the testing, which were found to be leak-free after the testing, indicating that they pass the required qualification test according to available standards. It is confirmed that adhesive joints can be a potential alternative when dealing with thermal and vibration fatigue in the common working conditions of HVAC&R systems.

The qualification testing is specific to the required loading conditions, such as pressure and temperature variations, and limited to certain tube sizes. An analytical model is developed to allow for design and evaluation across various operating conditions. The model aims to predict the adhesive stress and strain fields of in tube-to-tube joints based on the geometric parameters, material properties, and the loading conditions. In particular, the model uniquely considers the influence of thermal expansion and contraction in the joint, which is necessary for the periodically changing temperatures in HVAC&R systems. It is numerically solved using Mathematica and validated against the published data in the literature. The exact same solutions are achieved using the reported data in the literature, under simplified conditions without any temperature change involved. The validated model is then used in parametric studies to investigate the influence of geometric sizes and temperature change. Several conclusions are made about the trend of stress changes as well as the maximum stress, which provide insight from a perspective of general design guidance. Adhesive bonding length should be selected such that the maximum stress is smaller than the allowed material strength for both normal and shear stress. Adhesive thickness has less impact in the parametric range considered and is nevertheless usually dictated by the manufacture recommendation in view of other practical considerations. In regard to the thermal stresses, it is found that in practical HVAC&R working environment, the temperature-induced thermal stress dominates the stress fields and leads to significant change in the stress distribution across the adhesive layer. If a temperature change is present, the combination of all possible loading and temperature change should be analyzed to find the most extreme loading condition. This work demonstrates the first stress and strain analysis of tube-to-tube adhesive joints considering the working conditions of HVAC&R applications involving temperature cycling. All of these results provide a detailed guidance for use of adhesive joints across different application or locations in HVAC&R systems. The model can be also used as a framework to evaluate and compare the performance of different adhesives, as long as the adhesive properties are available.

Lastly, it is also essential to demonstrate the application of these joints in real HVAC&R systems. A proof-of-concept test was done to demonstrate that the use of adhesive joints in a real system would cause no change in operation or leakage. A commercial heat pump dryer system was used to perform the testing at the Ray W. Herrick Laboratories. Two adhesive joints were installed to replace the brazing joints at the compressor inlet and outlet, where the most extreme temperature and pressure conditions are present. Results show that the system operates without any change in performance and experience no obvious leakage after more than 50 hours of testing over 6 months.

This work explores the feasibility and reliability of adhesive bonding of copper for HVAC&R applications. The bonding strength of adhesive was studied and tested with both traditional surface preparation and advanced laser-interference structuring technique. The results show that for the tested structural epoxy adhesive, the bonding strength is large enough considering the internal pressure in the tube and the laser structure technique can increase the shear strength.

The long-term reliability with respect to thermal, stress and vibration fatigue are then experimentally investigated and the adhesive joints pass the qualifications tests required by the standard. Further modeling work for predicting the stress distribution in adhesively bonded joints is developed to understand the influence on geometric parameters and temperature change. The adhesive length can influence the stress distribution significantly and temperature-induced stress dominates the stress distribution under the HVAC&R loading conditions. Further material characterization is needed for crack propagation or detailed fatigue analysis, which is highly dependent on the adhesive formula, working environment and loading conditions, which can be performed with a more specific targeted application. The experimental and modeling work in this thesis provides a foundation for adhesives to be applied in HVAC&R applications and a framework to further develop, optimize, and utilize adhesive joining in HVAC&R applications.

碩士
崑山科技大學
光電工程研究所
106
Reliability of 460 nm GaN-Based LEDs with dominant wavelength affected by before die bond at different precuring temperatures was studied in this thesis. We have compared two combinations: Combination A horizontal LED die bonding on the ceramic leadframes, using die-attach adhesives silver paste thermal conductivity is 2 W/mK. Combination B vertical LED die bonding on the polyphthalamide leadframes, using die-attach adhesives silver paste thermal conductivity is 7.8 W/mK respectively. Precuring time were 10 minutes, the thickness of silver paste were controlled at 10 µm. Reliability test included with operating aging test at room temperature, high temperature and high humidity operating aging test, thermal shock test respectively. Comparison combination A after package affect by die-attach adhesives silver paste used 3 type precuring temperature conditions. Precuring temperatures were 30°C, 50°C and 80°C, after precuring die-bonding on the ceramic leadframes. According to the results of Fourier-transform infrared spectroscopy (FTIR) analysis, in results showed die-attach adhesives silver paste after precuring, solvent rate and water vapor will be reduce. According to the result of aging test for 1,008 hours at temperature 25°C and humidity 70%, LED operating current 100 mA, light output power remain 23.13%, 40.04%, 47.50% respectively. According to the result of high temperature and high humidity operating aging test for 504 hours at temperature 85°C and humidity 85%, LED operating current 100 mA, light output power remain 37.11%, 39.68%, 47.91% respectively. According to the results of thermal shock test at low temperature -45°C (20 minutes) and high temperature 125°C (20 minutes), after 500 cycles of thermal shock test, light output power remain 84.47%, 84.89%, 88.50% respectively. Comparison combination B after package affect by die-attach adhesives silver paste used not precuring and 2 type precuring temperature conditions. Precuring temperatures were not precuring, 50°C and 80°C, after precuring die-bonding on the polyphthalamide leadframes. According to the results of FTIR analysis, in results showed die-attach adhesives silver paste after precuring, solvent rate and water vapor will be reduce. According to the results of Scanning Electron Microscope (SEM) analysis, in results showed die-attach adhesives silver paste after precuring, silver more evenly distributed in the die-attach adhesives silver paste, reduce the gap in the die-attach adhesives silver paste after encapsulation, thereby improve the light reflection of the die-attach adhesives silver paste, then will be improve output flux of the LED, and also reducing the thermal resistance of the die-attach adhesives silver paste. According to the result of aging test for 1,008 hours at temperature 25°C and humidity 70%, LED operating current 350 mA, light output power remain 88%, 81%, 89% respectively. According to the results of thermal infrared camera detection of LED surface temperature, in results showed LED surface temperature after 1008 hours 95°C、84.7°C、80.3°C respectively. According to the result of high temperature and high humidity operating aging test for 1008 hours at temperature 85oC and humidity 85%, LED operating current 350 mA, light output power remain 80.35%, 81.25%, 82.27% respectively. According to the results of thermal shock test at low temperature -45°C (20 minutes) and high temperature 125°C (20 minutes), after 500 cycles of thermal shock test, light output power remain 94%, 94.71%, 95.67% respectively. According to the results after reliability test, in results showed after pre-curing, will affect LED in reliability test. Results showed two combination LED package, precuring temperature 80°C have best light output power in reliability test. Before die-bonding process die-attach adhesives silver paste proceed precuring, silver can be improved in the degree of dispersion in the die-attach adhesives silver paste, reduce the die-attach adhesives silver paste gap, increase the LED light output power and die-attach adhesives silver paste heat conductivity.

博士
國立清華大學
動力機械工程學系
99
Abstract For future advanced applications in consumer electronic products, the need of high-density and flexible interconnects increases rapidly. In this study, the reliability and flexibility of ultra-thin chip-on-flex (UTCOF) interconnects using anisotropic conductive adhesive (ACA) were investigated. A rigorous three-dimensional (3-D) numerical analysis model was performed using the ANSYS program. Moreover, experimental and parametric analyses of UTCOF interconnects were evaluated to establish the design rule of ACA-bonded UTCOF interconnects. Due to shrinkage of ACA resin and elastic-plastic characteristic of conductive particles, the effect of contact behavior in ACA joints on the contact resistance of the fabricated UTCOF interconnects after thermo-compression process was also estimated using a three-dimensional finite element model. The contact resistances obtained from the analysis results were in good agreement with experimental results, and can be used to predict the reliability performance in ACA joints. A process for manufacturing 20 ?慆-pitch compliant-bumps was proposed for COF structure using 2-layer ACA material. The reliability of the fabricated COF interconnects was evaluated by performing an 85°C/85％ relative humidity temperature-humidity storage test (RH THST) for 1,000 hours and a -55°C~125°C thermal cycling test (TCT) for 1,000 cycles. For UTCOF interconnects, the effect of chip thickness (25 ?慆, 35 ?慆, 50 ?慆) on the fracture strength of the ultra-thin silicon chip was estimated. Both the ACA-P and ACA-F materials were assembled at different bonding temperatures to study the temperature effects on the curing percentage and adhesion by differential scanning calorimeter (DSC) measurement and peeling test, respectively. Meanwhile, the relationship between curing conditions and electrical contact resistance was examined. Moreover, the bonding pressure effects on the electrical performance and deformation degree of conductive particles within the ACA resin were also explored. The contact resistance of daisy chain was measured to examine the bonding quality through the 80 ?慆 pitch dummy test samples using micro Au (gold) bump (GB) and compliant bump (CB). The reliability of the fabricated UTCOF interconnects bonded with selected ACA joints was evaluated by long-term 85°C/85％ RH THST for 7,000 hours and their flexibility was performed by static bending under various testing environments and 4-point bending tests. The interfaces between ultra-thin silicon chip and substrate for failed samples from THST and 4-point bending tests were then inspected through the cross-section scanning electron microscopy (SEM) works. Finite element analysis (FEA) was also conducted to interpret the failure mechanism of the UTCOF interconnects under 4-point bending test. Based on the results achieved, the UTCOF with ACA joints presented in this work would be reliable for serving as flexible interconnects for consumer electronic products. Also, the manufacturing technology for high-density and flexible UTCOF interconnects with ACA joints was thus established.