Journal articles: 'Growth of IMCs'

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Gu, X., D. Yang, Y. C. Chan, and B. Y. Wu. "Effects of electromigration on the growth of intermetallic compounds in Cu/SnBi/Cu solder joints." Journal of Materials Research 23, no. 10 (October 2008): 2591–96. http://dx.doi.org/10.1557/jmr.2008.0331.

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In this study, the effects of electromigration (EM) on the growth of Cu–Sn intermetallic compounds (IMCs) in Cu/SnBi/Cu solder joints under 5 × 103 A/cm2 direct current stressing at 308, 328, and 348 K were investigated. For each Cu/SnBi/Cu solder joint under current stressing, the IMCs at the cathode side grew faster than that at the anode side. The growth of these IMCs at the anode side and the cathode side were enhanced by electric current. The growth of these IMCs at the cathode followed a parabolic growth law. The kinetics parameters of the growth of the IMCs were calculated from the thickness data of the IMCs at the cathode side at different ambient temperatures. The calculated intrinsic diffusivity (D0) of the Cu–Sn IMCs was 9.91 × 10−5 m2/s, and the activation energy of the growth of the total Cu–Sn IMC layer was 89.2 kJ/mol (0.92 eV).

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Hang, Chunjin, Ruyu Tian, Liyou Zhao, and Yanhong Tian. "Influence of Interfacial Intermetallic Growth on the Mechanical Properties of Sn-37Pb Solder Joints under Extreme Temperature Thermal Shock." Applied Sciences 8, no. 11 (October 25, 2018): 2056. http://dx.doi.org/10.3390/app8112056.

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Solder joints in thermally uncontrolled microelectronic assemblies have to be exposed to extreme temperature environments during deep space exploration. In this study, extreme temperature thermal shock test from −196 °C to 150 °C was performed on quad flat package (QFP) assembled with Sn-37Pb solder joints to investigate the evolution and growth behavior of interfacial intermetallic compounds (IMCs) and their effect on the pull strength and fracture behavior of Sn-37Pb solder joints under extreme temperature environment. Both the scallop-type (Cu, Ni)6Sn5 IMCs at the Cu lead side and the needle-type (Ni, Cu)3Sn4 IMCs at the Ni-P layer side changed to plane-type IMCs during extreme temperature thermal shock. A thin layer of Cu3Sn IMCs was formed between the Cu lead and (Cu, Ni)6Sn5 IMC layer after 150 cycles. The growth of the interfacial IMCs at the lead side and the Ni-P layer side was dominated by bulk diffusion and grain-boundary diffusion, respectively. The pull strength was reduced about 31.54% after 300 cycles. With increasing thermal shock cycles, the fracture mechanism changed from ductile fracture to mixed ductile–brittle fracture, which can be attributed to the thickening of the interfacial IMCs, and the stress concentration near the interface caused by interfacial IMC growth.

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Lee, Chang Woo, Y. S. Shin, and J. H. Kim. "Precise Quantitative Evaluation of Nano-Ordered Intermetallic Compounds in Sn-3.0Ag-0.5Cu Lead-Free Solder Bump by Using TEM." Advanced Materials Research 47-50 (June 2008): 907–11. http://dx.doi.org/10.4028/www.scientific.net/amr.47-50.907.

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The growth behaviour of the intermetallic compounds (IMCs) in Pb-free solder bump is investigated. The Pb-free micro-bump, Sn-50%Bi, was fabricated by binary electroplating for flip-chip bond. The diameter of the bump is about 506m and the height is about 60 6m. In order to increase the reliability of the bonding, it is necessary to protect the growth of the IMCs in interface between Cu pad and the solder bump. For control of IMCs growth, SiC particles were distributed in the micro-solder bump during electroplating. The thickness of the IMCs in the interface was estimated by FE-SEM, EDS, XRF and TEM. From the results, The IMCs were found as Cu6Sn5 and Cu3Sn. The thickness of the IMCs decreases with increase the amount of SiC particles until 4 g/cm2. The one candidate of the reasons is that the SiC particles could decrease the area which be reacted between the solder and Cu layer. And another candidate is that the particle can make to difficult inter-diffusion within the interface.

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Mohd Salleh, Mohd Arif Anuar, N. S. Ibrahim, N. Saud, Mohd Mustafa Al Bakri Abdullah, N. Z. Noriman, Ramani Mayapan, and Z. A. Ahmad. "Research Development of Solder Materials and its Intermetallic Compound (IMC) Study." Advanced Materials Research 626 (December 2012): 797–801. http://dx.doi.org/10.4028/www.scientific.net/amr.626.797.

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Nowadays, the formation and the subsequent growth of the intermetallic compounds (IMCs) and the development of new lead-free solder systems is a major issue in soldering. The excessive growth formation of intermetallic compounds will increase the brittleness of solder joints and detrimentally affects its mechanical properties. This paper reviews the latest fabrication method for solder materials and the literatures of bulk IMCs study in most solder materials by other researchers. Explanation on solder fabrication by using powder metallurgy method to produce solder materials and IMCs study were explained in detail in this paper.

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Chen, Kuan-Jen, Fei-Yi Hung, Truan-Sheng Lui, and Wen-Yu Lin. "Effects of Static Heat and Dynamic Current on Al/Zn∙Cu/Sn Solder/Ag Interfaces of Sn Photovoltaic Al-Ribbon Modules." Materials 11, no. 9 (September 7, 2018): 1642. http://dx.doi.org/10.3390/ma11091642.

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This present study applied Cu∙Zn/Al ribbon in place of a traditional Cu ribbon to a photovoltaic (PV) ribbon. A hot-dipped and an electroplated Sn PV ribbon reflowed onto an Ag electrode on a Si solar cell and estimated the feasibility of the tested module (Ag/Solder/Cu∙Zn/Al). After bias-aging, a bias-induced thermal diffusion and an electromigration promoted the growth of intermetallic compounds (IMCs) (Cu6Sn5, Ag3Sn). To simulate a photo-generated current in the series connection of solar cells, an electron with Ag-direction (electron flows from Ag to Al) and Al-direction (electron flows from Al to Ag) was passed through the Al/Zn∙Cu/Solder/Ag structure to clarify the growth mechanism of IMCs. An increase in resistance of the Ag-direction-biased module was higher than that of the Al-direction biased one due to the intense growth of Cu6Sn5 and Ag3Sn IMCs. The coated solder of the electroplated PV ribbon was less than that of the hot-dipped one, and thus decreased the growth reaction of IMCs and the cost of PV ribbon.

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Said, Rita Mohd, Mohd Arif Anuar Mohd Salleh, Mohd Nazree Derman, Mohd Izrul Izwan Ramli, Norhayanti Mohd Nasir, and Norainiza Saud. "Isothermal Aging Affect to the Growth of Sn-Cu-Ni-1 wt.% TiO₂ Composite Solder Paste." Key Engineering Materials 700 (July 2016): 123–31. http://dx.doi.org/10.4028/www.scientific.net/kem.700.123.

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This work investigated the effects of 1.0 wt. % TiO2 particles addition into Sn-Cu-Ni solder paste to the growth of the interfacial intermetallic compound (IMC) on Cu substrate after isothermal aging. Sn-Cu-Ni solder paste with TiO2 particles were mechanically mixed to fabricate the composite solder paste. The composite solder paste then reflowed in the reflow oven to form solder joint. The reflowed samples were then isothermally aged 75, 125 and 150 ° C for 24 and 240 h. It was found that the morphology of IMCs changed from scallop-shape to a more uniform planar shape in both Sn-Cu-Ni/Cu joints and Sn-Cu-Ni-TiO2 /Cu joint. Cu6Sn5 and Cu3Sn IMC were identified and grew after prolong aging time and temperature. The IMCs thickness and scallop diameter of composite solder paste were reduced and the growth of IMCs thickness after isothermal aging become slower as compared to unreinforced Sn-Cu-Ni solder paste. It is suggested that TiO2 particles have influenced the evolution and retarded the growth of interfacial IMCs.

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Guo, Mengjiao, F. Sun, and Zuozhu Yin. "Microstructure evolution and growth behavior of Cu/SAC105/Cu joints soldered by thermo-compression bonding." Soldering & Surface Mount Technology 31, no. 4 (September 2, 2019): 227–32. http://dx.doi.org/10.1108/ssmt-08-2018-0025.

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Purpose This paper used a novel technique, which is thermo-compression bonding, and Sn-1.0Ag-0.5Cu solder to form a full intermetallic compound (IMC) Cu3Sn joints (Cu/Cu3Sn/Cu joints). The purpose of the study is to form high-melting-point IMC joints for high-temperature power electronics applications. The study also investigated the effect of temperature gradient on the microstructure evolution and the growth behavior of IMCs. Design/methodology/approach In this paper, the thermo-compression bonding technique was used to form full Cu3Sn joints. Findings Experimental results indicated that full Cu/Cu3Sn/Cu solder joints with the thickness of about 5-6 µm are formed in a short time of 9.9 s and under a low pressure of 0.016 MPa at 450°C by thermo-compression bonding technique. During the bonding process, Cu6Sn5 grew with common scallop-like shape at Cu/SAC105 interfaces, which was followed by the growth of Cu3Sn with planar-like shape between Cu/Cu6Sn5 interfaces. Meanwhile, the morphology of Cu3Sn transformed from a planar-like shape to wave-like shape until full IMCs solder joints were eventually formed during thermo-compression bonding process. Asymmetrical growth behavior of the interfacial IMCs was also clearly observed at both ends of the Cu/SAC105 (Sn-1.0Ag-0.5Cu)/Cu solder joints. Detailed reasons for the asymmetrical growth behavior of the interfacial IMCs during thermo-compression bonding process are given. The compound of Ag element causes a reduction in Cu dissolution rate from the IMC into the solder solution at the hot end, inhibiting the growth of IMCs at the cold end. Originality/value This study used the thermo-compression bonding technique and Sn-1.0Ag-0.5Cu to form full Cu3Sn joints.

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Xue, Peng, Jianzhi Tao, Peng He, Weimin Long, and Sujuan Zhong. "The Enhanced Mechanism of 0.05 wt. % Nd Addition on High Temperature Reliability of Sn-3.8Ag-0.7Cu/Cu Solder Joint." Applied Sciences 10, no. 24 (December 15, 2020): 8935. http://dx.doi.org/10.3390/app10248935.

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In this study, the effect of appropriate Nd addition on improving the high-temperature reliability of Sn-3.8Ag-0.7Cu (SAC387)/Cu solder joint after aging treatment was investigated. The interfacial microstructure of solder joint was refined with proper addition of Nd. This phenomenon could be explained as the adsorbing-hindering effect of surface-active Nd atoms which blocked the growth of brittle intermetallic compounds (IMCs) in the solder joint. Theoretical analysis indicated that 0.05 wt. % addition of Nd could distinctly decrease the growth constant of Cu6Sn5 IMCs and slightly decrease the growth constant of Cu3Sn IMCs respectively. The shear force of SAC387-0.05Nd/Cu solder joint was evidently improved compared with the origin solder joint. In addition, SAC387-0.05Nd/Cu solder joint maintained excellent mechanical property compared with SAC387/Cu solder joint even after 1440 h aging treatment.

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Hayashi, Yawara, Ikuo Shohji, Yusuke Nakata, and Tomihito Hashimoto. "Effect of Added Elements on Microstructures and Joint Strength of Lead-Free Sn-Based Solder Joint Dispersed IMC Pillar." Materials Science Forum 879 (November 2016): 2216–21. http://dx.doi.org/10.4028/www.scientific.net/msf.879.2216.

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To create a high reliability solder joint using IMCs dispersed in the joint, the joints with four types of lead-free solder were investigated. The joint with Sn-3.0Ag-0.7Cu-5.0In (mass%) has high die shear force compared to other joints investigated, and the joint with the Ni-electroplated Cu bonded at 300 oC for 30 min showed the maximum die shear force due to formation of a large number of fine IMCs. In the joint with Sn-0.7Cu-0.05Ni (mass%), uniform dispersion of a large number of IMCs was achieved, although the die shear force of the joint is lower than that of the joint with Sn-3.0Ag-0.7Cu-5.0In. In the joint with Sn-5.0Sb (mass%), a solder area was remained in the center of the joint although a large number of columnar IMCs form at the joint interface. The die shear force of the joint with Sn-5.0Sb increased with increasing the bonding time due to formation and growth of IMCs. In the joint with Sn-3.0Ag-0.5Cu (mass%), IMCs formed at the joint interface and did not disperse in the entire joint.

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Chen, Jieshi, Yongzhi Zhang, Zhishui Yu, Peilei Zhang, Wanqin Zhao, Jin Yang, and Di Wu. "Interface Growth and Void Formation in Sn/Cu and Sn0.7Cu/Cu Systems." Applied Sciences 8, no. 12 (December 19, 2018): 2703. http://dx.doi.org/10.3390/app8122703.

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In this work, the effects of electroplated Cu (EP Cu) and Cu addition (0.7%) in Sn solder on the intermetallic compounds (IMCs) growth and void formation were clarified by comparison with solder joints comprising of high purity Cu (HP Cu) substrate and pure Sn solder. After aging processes, a new IMC, Cu3Sn, was formed at the interface, in addition to Cu6Sn5 formed in the as-soldered joints. The EP Cu and Cu addition (0.7%) both had limited effects on the total IMCs thickness. However, the effects varied on the growth behaviors of different IMCs. Comparing to the void-free interface between Sn and HP Cu, a large number of voids were observed at the Cu3Sn/Cu interface in Sn/EP Cu joints. The formation of these voids may be induced by the impurities and fine grain, which were introduced during the electroplating process. The addition of Cu suppressed the inter-diffusion of Cu and Sn at the interface. Consequently, the growth of the Cu3Sn layer and formation of voids were suppressed.

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Sungkhaphaitoon, Phairote, and Tanyaporn Suwansukho. "Effects of Bismuth Content on the Microstructure, Shear Strength and Thermal Properties of Sn-0.7Cu-0.05Ni Solder Joints." Materials Science Forum 982 (March 2020): 115–20. http://dx.doi.org/10.4028/www.scientific.net/msf.982.115.

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The effects of bismuth content on the microstructure, shear strength and thermal properties of Sn-0.7Cu-0.05Ni solder joints were investigated. Adding 2 wt% elemental Bi to Sn-0.7Cu-0.05Ni solder joints reduced peak temperature by about 6.7 °C, increased pasty range by 4.2 °C and raised undercooling by 3.1 °C. The microstructure of the interfacial layer between solder and Cu substrate was composed of (Cu,Ni)6Sn5 and (Cu,Ni)3Sn intermetallic compounds (IMCs). The solder joint included a phase of SnBi and Cu6Sn5 IMCs. The addition of elemental Bi increased shear strength and suppressed the growth of IMCs in the interfacial layer of the solder joints.

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Najib, S. I., Mohd Arif Anuar Mohd Salleh, and Saud Norainiza. "Effect of Aging Temperature on the Intermetallic Compound (IMC) Formation of Sn-0.7Cu/Si₃N₄ Composite Solder." Advanced Materials Research 795 (September 2013): 522–25. http://dx.doi.org/10.4028/www.scientific.net/amr.795.522.

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Nowadays, excessive growth intermetallic formation becomes the major issue in electronic packaging industry. The investigation on the effect of aging temperature to the intermetallic compound (IMCs) growth formation for Sn-0.7Cu/1.0-Si3N4 was studied. Isothermal aging process was carried out for 24 hours, with 5 difference aging temperature from 50°C up to 150°C. It is found that the Cu-Sn IMCs which appear after reflowed process, has grew rapidly when aging temperature was increased up to 125°C and started to reduced after 150°C aging temperature.

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Yu, Shan-Pu, Moo-Chin Wang, and Min-Hsiung Hon. "Formation of intermetallic compounds at eutectic Sn–Zn–Al solder/Cu interface." Journal of Materials Research 16, no. 1 (January 2001): 76–82. http://dx.doi.org/10.1557/jmr.2001.0015.

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The eutectic Sn–Zn–Al solder alloy was used [composition: 91Sn–9(5Al–Zn)] to investigate the intermetallic compounds (IMCs) formed between solder and a Cu substrate. Scanning electron microscope, transmission electron microscope, and electron diffraction analysis were used to study the IMCs between solder and a Cu substrate. The γ–Cu5Zn8 and γ–Cu9Al4 IMCs were found at the Sn–Zn–Al/Cu interface. Thermodynamic calculation can explain the formation of γ–Cu5Zn8 and γ–Cu9Al4 IMCs instead of Cu–Sn compounds. The formation and growth of γ–Cu9Al4 IMC at 423 K resulted in the decrease of adhesion strength at the interface of solder and a Cu substrate, where the Kirkendall voids were severely formed. As the heating time increased up to 1000 h at 423 K, the adhesion strength between the eutectic Sn–Zn–Al solder and a Cu substrate decreased from 7.6 ± 0.7 MPa to 4.4 ± 0.8 MPa.

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Tian, Ye, Heng Fang, Ning Ren, Chao Qiu, Fan Chen, and Suresh Sitaraman. "Intermetallics evolution and its reliability effects on micro-joints in flip chip assemblies." Microelectronics International 37, no. 3 (January 27, 2020): 117–24. http://dx.doi.org/10.1108/mi-07-2019-0048.

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Purpose This paper aims to assess precise correlations between intermetallic compounds (IMCs) microstructure evolutions and the reliability of micro-joints with a Cu/SAC305solder/Ni structure using thermal shock (TS) tests. Design/methodology/approach This paper uses 200-µm pitch silicon flip chips with nickel (Ni) pads and stand-off height of approximately 60 µm, assembled on substrates with copper (Cu) pads. After assembly, the samples were subjected to air-to-air thermal shock testing from 55 to 125 per cent. The transfer time was less than 5 s, and the dwell time at each temperature extreme was 15 min. To investigate the microstructure evolution and crack growth, two samples were removed from the thermal shock chamber at 0, 400, 1,200, 2,000, 5,800 and 7,000 cycles. Findings The results showed that one (Cu, Ni)6Sn5/(Ni, Cu)3Sn4 dual-layer structure formed at the Ni pad interface of chip side dominates the micro-joints failure. This is because substantial (Ni, Cu)3Sn4 grain boundaries provide a preferential pathway for the catastrophic crack growth. Other IMCs microstructure evolutions that cause the prevalent joints failure as previously reported, i.e. thickened interfacial (Cu, Ni)6Sn5 and Ni3P layer, and coarsened IMCs inside the solder matrix, only contributed to the occurrence of fine cracks. Moreover, the typical interfacial IMCs spalling triggered by thermally induced stress did not take place in this study, showing a positive impact in the micro-joint reliability. Originality/value As sustained trends toward multi-functionality and miniaturization of microelectronic devices, the joints size is required to be constantly scaled down in advanced packages. This arises a fact that the reliability of small-size joints is more sensitive to the IMCs because of their high volume proportion and greatly complicated microstructure evolutions. This paper evaluated precise correlations between IMCs microstructure evolutions and the reliability of micro-joints with a Cu/SAC305solder/Ni structure using TS tests. It found that one (Cu, Ni)6Sn5/(Ni, Cu)3Sn4 dual-layer structure formed at the Ni pad interface dominate the micro-joints failure, whereas other IMCs microstructure evolutions that cause the prevalent joints failure exhibited nearly negligible effects.

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Pawełkiewicz, M., Marek Danielewski, Jolanta Janczak-Rusch, and Bartek Wierzba. "Modeling of Multi-Phase Solid State Reactions-Case of IMC Growth." Defect and Diffusion Forum 323-325 (April 2012): 127–32. http://dx.doi.org/10.4028/www.scientific.net/ddf.323-325.127.

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The formation of intermetallic compounds (IMC) at the solder-substrate interface is required to initiate the metallurgical bond. However, rapid growth of IMCs may degrade joint strength through i) the increased presence of a low toughness phase, ii) the consumption of the solderable surface (void formation) and iii) generation of primary and secondary stresses. Knowledge of mass transport and reaction processes during joint formation and service life are essential for solder system design. The mathematical description of inter-and reactive diffusion in open system presented here is based on Darken method (bi-velocity), involving the different molar volumes in the system and Wagner boundary conditions. It combines the interdiffusion, reactive diffusion and the effective flux constraints to couple processes occurring at different time scales. The rCADiff software serves as a tool to simulate simultaneous growth of the two Cu-Sn IMCs.

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Yu, D. Q., C. M. L. Wu, D. P. He, N. Zhao, L. Wang, and J. K. L. Lai. "Effects of Cu Contents in Sn–Cu Solder on the Composition and Morphology of Intermetallic Compounds at a Solder/Ni Interface." Journal of Materials Research 20, no. 8 (August 1, 2005): 2205–12. http://dx.doi.org/10.1557/jmr.2005.0275.

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The reaction between Sn–xCu (x = 0.1, 0.3, 0.7, 0.9, and 1.5 wt%) solder alloys and Ni at 260, 280, and 290 °C for 60 s was studied to reveal the effect of Cu content on the composition and morphology of intermetallic compounds (IMCs) formed at the interface between solder and substrate. The results indicated that Cu concentration greatly affects both the composition and morphology of the IMC between the solder and Ni substrate. In particular, when the Cu concentration was less than or equal to0.3 wt%, (CuxNi1−x)3Sn4 IMCs were formed at the interface. When the Cu concentration was 0.7 wt%, large facets type of (CuxNi1−x)6Sn5 were mixed with (CuxNi1−x)3Sn4 in the IMC layer. At Cu concentrations higher than the eutectic one, e.g., 0.9 and 1.5 wt%, stick-shaped (CuxNi1−x)6Sn5 compounds were detected, but the (CuxNi1−x)3Sn4 IMCs disappeared. The formation and growth mechanism of the (CuxNi1−x)6Sn5 compound were analyzed. The evolution tendency of the composition and morphology of the IMCs at the three testing temperatures was found to be the same.

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Gu, Yue, Ying Liu, Xiu Chen Zhao, Shu Lai Wen, Hong Li, and Yuan Wang. "Effects of Cobalt Nanoparticles Addition on Shear Strength, Wettability and Interfacial Intermetallic Growth of Sn−3.0Ag−0.5Cu Solder during Thermal Cycling." Materials Science Forum 815 (March 2015): 97–102. http://dx.doi.org/10.4028/www.scientific.net/msf.815.97.

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In the present study, Cobalt nanoparticles were synthesized and mixed with Sn-3.0Ag-0.5Cu solder (SAC305). The effect of 0.05 wt.%, 0.2 wt.%, 0.5 wt.% and 1.0 wt.% Co nanoparticles on the wettability, the shear strength as well as the growth of intermetallic compounds (IMCs) at composite solder/Cu interface during thermal cycling were investigated. Results show that Co nanoparticle addition can considerably improve wettability, increase the shear strength and suppress the growth of interfacial IMCs. The addition amount of Co nanoparticles have the consistent relation with the improvement extent of the wettability, shear strength and the growth rate of interfacial IMCs. Slight addition (0.05 wt.% and 0.2 wt.%) can significantly improve the properties of nanocomposite solder in all the three aspects. However, with excessive addition amount (0.5 wt.% and 1.0 wt.%) of Co nanoparticles, the improvement extent will decline. The Cross-section images of the interface of nanocomposite solder/Cu joint show that Co can form reinforcement particles in the solder and can act as the sacrificial element to substitute Cu to react with Sn. Excessive Co nanoparticles would form large amount of hard and brittle intermetallics which leads to decreasing shear strength of the composite solder.

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Willimsky, Gerald, Melinda Czéh, Christoph Loddenkemper, Johanna Gellermann, Karin Schmidt, Peter Wust, Harald Stein, and Thomas Blankenstein. "Immunogenicity of premalignant lesions is the primary cause of general cytotoxic T lymphocyte unresponsiveness." Journal of Experimental Medicine 205, no. 7 (June 23, 2008): 1687–700. http://dx.doi.org/10.1084/jem.20072016.

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Cancer is sporadic in nature, characterized by an initial clonal oncogenic event and usually a long latency. When and how it subverts the immune system is unknown. We show, in a model of sporadic immunogenic cancer, that tumor-specific tolerance closely coincides with the first tumor antigen recognition by B cells. During the subsequent latency period until tumors progress, the mice acquire general cytotoxic T lymphocyte (CTL) unresponsiveness, which is associated with high transforming growth factor (TGF) β1 levels and expansion of immature myeloid cells (iMCs). In mice with large nonimmunogenic tumors, iMCs expand but TGF-β1 serum levels are normal, and unrelated CTL responses are undiminished. We conclude that (a) tolerance to the tumor antigen occurs at the premalignant stage, (b) tumor latency is unlikely caused by CTL control, and (c) a persistent immunogenic tumor antigen causes general CTL unresponsiveness but tumor burden and iMCs per se do not.

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Chowdhury, A. H. M. Yeaseen, Md Kaysher Hamid, and Rowshonara Akter Akhi. "IMPACT OF MACROECONOMIC VARIABLES ON ECONOMIC GROWTH: BANGLADESH PERSPECTIVE." Information Management and Computer Science 2, no. 2 (October 31, 2019): 19–22. http://dx.doi.org/10.26480/imcs.02.2019.19.22.

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Wu, Jie, Songbai Xue, Jingwen Wang, and Guoqiang Huang. "Effect of 0.05 wt.% Pr Addition on Microstructure and Shear Strength of Sn-0.3Ag-0.7Cu/Cu Solder Joint during the Thermal Aging Process." Applied Sciences 9, no. 17 (September 2, 2019): 3590. http://dx.doi.org/10.3390/app9173590.

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The evolution of interfacial morphology and shear strengths of the joints soldered with Sn-0.3Ag-0.7Cu (SAC0307) and SAC0307-0.05Pr aged at 150 °C for different times (h; up to 840 h) were investigated. The experiments showed the electronic joint soldered with SAC0307-0.05Pr has a much higher shear strength than that soldered with SAC0307 after each period of the aging process. This contributes to the doping of Pr atoms, “vitamins in alloys”, which tend to be adsorbed on the grain surface of interfacial Cu6Sn5 IMCs, inhibiting the growth of IMCs. Theoretical analysis indicates that doping 0.05 wt.% Pr can evidently lower the growth constant of Cu6Sn5 (DCu6), while the growth constant of Cu3Sn (DCu3) decreased slightly. In addition, the electronic joint soldered with SAC0307-0.05Pr still has better ductility than that soldered with SAC0307, even after a 840-h aging process.

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Qu, Jun Feng, Jun Xu, Qiang Hu, and Fu Wen Zhang. "Microstructure and Growth Behavior of the Intermetallic Compound for Sn-1.0Ag-0.5Cu-NiB/Cu Solder Joint Interface." Advanced Materials Research 652-654 (January 2013): 1106–10. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.1106.

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This research investigates the microstructure and growth behavior of the intermetallic compound(IMC) of Sn-1.0Ag-0.5Cu,Sn-1.0Ag-0.5Cu-0.05Ni and Sn-1.0Ag-0.5Cu-0.05N-0.02B/Cu solder joint interface. The interfacial reactions between Cu and the solders at 250±1°C were examined. Experimental results indicated that the IMCs of the above alloy systems on the soldering interface were Cu6Sn5and (Cux, Ni1-x)6Sn5, respectively. The grain size of primary Sn decreased observably with the micro addition of B and a large number of fine reinforcement particles were found in the solder. With the aging time increasing, the (Cux, Ni1-x)6Sn5micrograph of the Sn-1.0Ag-0.5Cu-0.05N-0.02B solder joint interface was changed from sawtooth-like to shape-layer, but the thickness of IMCs increased unobservably.

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Wang, Qingfeng, Hong Chen, and Fengjiang Wang. "Effect of Trace Zn Addition on Interfacial Evolution in Sn-10Bi/Cu Solder Joints during Aging Condition." Materials 12, no. 24 (December 17, 2019): 4240. http://dx.doi.org/10.3390/ma12244240.

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Excessive growth of intermetallic compounds (IMCs) during service affects the reliability of solder joints, so how to suppress the growth of IMC thickness at the interface in solder joints becomes a widespread concern. In this work, the interfacial reaction between Sn-10Bi solder and Cu substrate after thermal aging was investigated. Moreover, to depress the IMC growth at the interface, trace amounts of Zn was added into the Sn-10Bi solder, and the interfacial reactions of Sn-10Bi-xZn solders (x = 0.2, 0.5) and Cu substrate after thermal aging were studied in this paper. Compounds such as Cu6(Sn, Zn)5 and Cu5Zn8 were formed at the interface after adding trace amounts of Zn. The addition of 0.2 and 0.5 wt% Zn significantly inhibited the thickness growth of IMCs and the formation of Cu3Sn IMC at the interface of Sn-10Bi-0.2Zn/Cu and Sn-10Bi-0.5Zn/Cu during thermal aging. Therefore, the addition of trace Zn had an obvious effect on the interfacial reaction of Sn-10Bi/Cu solder joint. Interestingly, the evolution of IMC thickness in Sn-10Bi-0.5Zn/Cu solder joints was completely different from that in Sn-10Bi or Sn-10Bi-0.2Zn solder joints, in which the spalling of IMCs occurred. In order to explore the mechanisms on the depressing effect from the addition of trace Zn, the activation energy Q in solder joints during aging was calculated.

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Hong, Kairong, Yong Wang, Jianjun Zhou, Canfeng Zhou, and Luming Wang. "Investigation on ultrasonic assisted friction stir welding of aluminum/steel dissimilar alloys." High Temperature Materials and Processes 40, no. 1 (January 1, 2021): 45–52. http://dx.doi.org/10.1515/htmp-2021-0011.

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Abstract The extensive use of light metal material such as aluminum has brought about problems in its joining with steel. However, the weak metallurgical bonding between the dissimilar materials and the formation of hard and brittle intermetallic compounds (IMCs) lead to unsatisfactory joint strength. Aiming at achieving high-quality joining of aluminum and steel, 6061-T6 aluminum and 301L steel alloys were lap joined by ultrasonic assisted friction stir lap welding (UaFSLW) in this study. The UaFSLW joints were well formed with uniform flashes and even arc lines. The strong plastic flow of the aluminum material driven by the dual effects of mechanical stirring and ultrasonic vibration inhibited the excessive growth of the Al–Fe IMCs at the lap interface. Thanks to the enhanced metallurgical bonding and the effective control of the layer thickness of IMCs, the tensile load of the UaFSLW joint under 1,800 rpm reached 16.5 kN, which was an increase of 27.9% compared to that of the conventional FSLW joint.

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Yang, Wenchao, Zuojun Yang, Yaokun Fu, Aihua Yu, Junli Feng, and Yongzhong Zhan. "Effect of Graphene Nanosheet Addition on the Wettability and Mechanical Properties of Sn-20Bi-xGNS/Cu Solder Joints." Materials 13, no. 18 (September 8, 2020): 3968. http://dx.doi.org/10.3390/ma13183968.

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Graphene nanosheets (GNSs) have an extensive application in materials modification. In this study, the effects of graphene nanosheets on the wettability of Sn-20Bi lead-free solder on copper (Cu) substrate and the growth behavior of intermetallic compound (IMC) layers at Sn-20Bi-xGNS/Cu solder joints were investigated. The experimental results indicate that the wettability of Sn-20Bi solder firstly diminished and then increased by the addition of GNSs. Meanwhile, a prism-shaped and scallop-shaped Cu6Sn5 IMC layer was clearly observed at the interface of the solder/substrate system. Moreover, it was found that a small amount of GNS addition can significantly inhibit the growth of the IMC layer at the interface as well as refine the microstructure. Additionally, by nano-indentation apparatus, it can be concluded that the hardness and elastic module of IMCs show the same variation trend, which firstly decreased and then increased. Besides, to intuitively demonstrate the reliability of IMCs, the relationship between the hardness and elastic module was established, and the ratio of hardness/elastic module (H/E) was adopted to characterize the reliability of IMCs. The results show that when the addition of GNSs was 0.02 wt%, the value of H/E is the minimum and the solder joint has the highest reliability.

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Wang, Yi Yu, Qiang Guo Luo, Qiang Shen, Chuan Bin Wang, and Lian Meng Zhang. "Effect of Holding Time on Microstructure and Mechanical Properties of Diffusion-Bonded Mg1/Pure Ag Foil/1060Al Joints." Key Engineering Materials 616 (June 2014): 280–85. http://dx.doi.org/10.4028/www.scientific.net/kem.616.280.

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Mg1 and 1060 Al were diffusion-bonded by using pure silver foil under different holding times (10 min~120 min). The interface of the joint consists of Mg-Ag diffusion zone, Ag foil interlayer and Ag-Al diffusion zone. The distributions of Mg, Ag and Al show ladder-like distributions at the interface of the joints. When the holding time is below 90 min, silver foil has impeded the inter-diffusion of Mg and Al. When the holding time is beyond 90 min, the brittle eutectic Mg-Al intermetallic compounds (IMCs) cannot be avoided. Mg3Ag and MgAg intermetallic compounds formed on Mg base side. Ag2Al intermetallic compound grew on Al base side. The thicknesses of Mg3Ag, MgAg and Ag2Al increased linearly with the increasing holding time, which is contrary to that of the silver foil. The growth rate relationship of the formed IMCs is MgAg > Ag2Al > Mg3Ag according the slope values of the fitted lines. The hardness sharply increased at the interface because of the formation of IMCs. The maximum hardness values of three IMCs Mg3Ag, MgAg and Ag2Al are 287.5 HV, 196.5 HV and 175.7 HV respectively. The hardness of each IMC layer increased with the extension of holding time. The shear strength of the joints decreased from 10.5 MPa to 4.6 MPa with the rising holding time.

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Zhang, Xue Chao, Jing Wei Cheng, Bing Zheng, Xiu Chen Zhao, Ying Liu, and Ping Chen. "Nickel Nanoparticles Mediated Growth of the Intermetallic Compound between Sn-1.0Ag-Xni Solders Alloy and Cu Substrate." Materials Science Forum 815 (March 2015): 103–8. http://dx.doi.org/10.4028/www.scientific.net/msf.815.103.

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In the present study, the effect of addition of Ni nanoparticles on the growth of the intermetallic compound (IMC) layer between low-silver lead-free solder and Cu substrate was investigated. Ni nanoparticles were synthesized and smelted with pure Sn, Ag to prepare Sn-1.0Ag-xNi (x=0, 0.05, 0.1, 0.2) solder alloy. Sn-1.0Ag-xNi was soldered on a copper substrate, and then the solder/Cu couples were isothermally aged at 423K for 360h.The Cross-section images of IMCs layer were obtained to observe the morphology of IMC and to measure the thickness of Cu6Sn5and Cu3Sn layers respectively. The results show that, during aging, addition of Ni can remarkably improve the morphology of IMC, level the scalloped IMC, facilitate the growth of the total interfacial IMCs and inhibit the growth of Cu3Sn. Moreover, the rate change of thickness of the Cu3Sn reduced obviously with the increase of Ni nanoparticles. Comprehensive analysis shows that the addition of Ni promotes the nucleation and growth of Cu6Sn5. The thermodynamics calculation on the solder alloy was identical with the experiment result.

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Han, Bangyao, Fenglian Sun, Tianhui Li, and Yang Liu. "Microstructure evolution of Au/SnSb-CuNiAg/(Au)Ni during high temperature aging." Soldering & Surface Mount Technology 32, no. 2 (September 25, 2019): 57–64. http://dx.doi.org/10.1108/ssmt-04-2019-0015.

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Purpose The purpose of this paper is to investigate the morphology evolution and the composition transformation of Au-Sn intermetallic compounds (IMCs) of the new Au/Sn-5Sb-1Cu-0.1Ni-0.1Ag/(Au)Ni solder joint during the high temperature aging. Design/methodology/approach Sn-5Sb-1Cu-0.1Ni-0.1Ag solder balls (500 µm in diameter), heat sink with structure of 7.4 µm Au layer on 5 µm Ni-plated Cu alloy and Si chip with 5.16 µm plated Au were used to fabricate micro-solder joints. The joints were performed in a furnace at 150°C for 150, 250 and 350 h aging. The samples were polished and deep etched before analyzed by metallographic microscope and scanning electron microscopy, respectively. Energy dispersive x-ray spectroscopy was used to identify the composition of the IMCs. Findings ß-(Au,Ni,Cu)10Sn phase is formed during the soldering process. The IMCs evolution has two periods during the aging. The first is the ξ-(Au,Ni,Cu)5Sn, ξ-(Au,Cu)5Sn and δ-AuSn were formed and grew to form a full-compound joint after about 150 h aging. The second is the conversion of the full-compound joint. The IMCs converted to ξ′ phase when the aging time extends to 250 h, and transformed to ε-(Au,Ni,Cu)Sn2 and η-(Au,Ni,Cu)Sn4 after 350 h aging. The thicker gold layer and thinner solder joint can promote the growth of the IMCs. ß-(Au,Ni,Cu)10Sn emerged in Au/SnSb-CuNiAg/(Au)Ni in this research, which is not usually found. Originality/value The results in this study have a significant meaning for the application of the new Sn-5Sb-1Cu-0.1Ni-0.1Ag in harsh conditions.

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Nazri, S. F., and Mohd Arif Anuar Mohd Salleh. "The Effects of Gallium Additions on the Microstructure of Lead-Free Solder Materials: A Short Review." Solid State Phenomena 280 (August 2018): 187–93. http://dx.doi.org/10.4028/www.scientific.net/ssp.280.187.

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This paper reviews the results of gallium (Ga) additions on the properties of Lead (Pb)-free solder alloys in terms of the solderability, microstructure and mechanical properties. Throughout the review, it is proven that when 0.5% of Ga is added, the shear force is improved and the grain size of the solder has refined remarkably. Besides, the addition of Ga has significantly suppressed the interfacial intermetallic compounds (IMCs) formation at solder/Copper substrate interface. This is caused by the formation of the Cu2Ga phase around the joint surface during solidification which decrease the growth rate of the IMCs layer. In fact, the enhancement in the mechanical aspect can also be affiliated with the improvement of the IMCs of the solder due to the addition of Ga. Moreover, Ga element also added to act as solid solution strengthening in β-Sn matrix. Furthermore, the addition of Ga element definitely decreases the melting temperature of Pb-free solder in Sn-0.7Cu Pb-free solder. As Ga addition also improve the oxidation resistance and reduce the surface tension of the solder, thus the solderability of the Pb-free solder alloys is slightly improved.

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Koo, Ja Myeong, Dea Gon Kim, and Seung Boo Jung. "Reliability of Electroplated Sn-37Pb Solder Bumps with Different Under Bump Metallizations (UBMs) during High Temperature Storage Test." Solid State Phenomena 124-126 (June 2007): 5–8. http://dx.doi.org/10.4028/www.scientific.net/ssp.124-126.5.

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The interfacial reactions and shear properties of Sn-37Pb (wt.%) solder bumps with two different under bump metallizations (UBMs), Cu and Ni, were investigated after high temperature storage (HTS) tests at 150 C for up to 65 days. Two different intermetallic compounds (IMCs), Cu6Sn5 and Cu3Sn, were formed at the bump/Cu interface, whereas only a Ni3Sn4 IMC layer was formed at the bump/Ni interface. The thicknesses of these IMCs increased linearly with the square root of duration time. The IMC growth rate at the bump/Cu UBM interface was much greater than that at the bump/Ni UBM interface. The shear properties of the bumps with the Cu UBM were greatly decreased with increasing duration time, compared with those with the Ni UBM.

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Hirose, Akio, Hirotaka Imaeda, Miki Kondo, and Kojiro F. Kobayashi. "Influence of Alloying Elements on Interfacial Reaction and Strength of Aluminum/Steel Dissimilar Joints for Light Weight Car Body." Materials Science Forum 539-543 (March 2007): 3888–93. http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.3888.

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Dissimilar joining of Al alloys and steel was carried out using diffusion bonding process. The effects of Si and Mg contents of Al alloys and bonding parameters on the interfacial reaction were fundamentally investigated. While the reaction layers consisting of Fe-Al type intermetallic compounds (IMCs) formed at the interfacial region, in the joint with Al alloys including 1mass% Si or more a ternary Fe-Al-Si IMC layer formed at the Al alloy side. The growth of the reaction layers followed the parabolic growth low. A maximum joint strength was obtained at an average reaction layer thickness ranging from 0.5 to 1μm. The thicker reaction layer caused the fracture of the joints at a lower stress because of brittleness of the IMCs, and the thinner reaction layer including un-bonded interface also resulted in a low joint strength. As a result a thin and uniform reaction layer including less un-bonded interface can realize a high joint strength. Since the Fe-Al-Si IMC layer uniformly formed more rapidly than the binary Fe-Al IMCs in the joint with Al alloys including 1mass% Si or more, a higher joint strength was obtained at a thinner average reaction layer. As a result, it was found that the chemical compositions of 6000 series Al alloy controlled to be Mg (0.6 to 1.0mass%) and Si (more than 1.0mass%) were appropriate to obtain the better bonding characteristics.

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Deng, Jun, Wei Li, Jiang-Hua Dai, Qian-Kun Gao, Liang Hao, Yi Ding, Tao Nie, Min Dai, Jun Luo, and Qi-Ming Huang. "Rapid Repair of Goat Large Segmental Loading Bone Defect and Functional Reconstruction by Interventional Micro-Circulation System." Journal of Biomaterials and Tissue Engineering 9, no. 8 (August 1, 2019): 1045–51. http://dx.doi.org/10.1166/jbt.2019.2112.

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Objective: This study aimed to explore the efficacy of interventional micro-circulation system (IMCS), combining the stromal cell-derived factor 1 (SDF-1)/type I collagen/chitosan composite membrane into TEB in treating with the model of goat tibial LSBD. Methods: The model of goat tibial LSBD was constructed by introducing the IMCS and SDF-1 guiding membrane. Perfusion treatment of CXCR4 + -BMSCs and BMP-2 was performed on the animal model, general conditions of the goats were observed, and changes in the goat's tibia was observed at different time points through imaging techniques. Using RNA extraction and reverse transcription, cDNA was acquired. Alkaline phosphatase (ALP), core binding factor-α1 (Cbfα1) and osteocalcin (OC) content, as well as the mRNA of transformation growth factor-β1 (TGF-β1) in fixed bone tissue samples of the goat, were detected by real-time quantitative PCR (RT-qPCR). Results: The model of goat tibial LSBD repaired by IMCS was successfully constructed. The standing, walking and running functions of the goat recovered well after two months; and imaging revealed that the callus was closely connected and most of the scaffold materials of TEB were absorbed. The detection of the ALP gene in bone tissue samples failed, and the amplified product was non-specific. Furthermore, the levels of Cbfα1, OC and mRNA of TGF-β1 were significantly higher than in normal bones (P < 0.05). Conclusion: The combination treatment of IMCS with slow controlled drug delivery systems and TEB functioned well in repairing goat tibial LSBD. This is a novel method for repairing bone defects.

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Date, M., K. N. Tu, T. Shoji, M. Fujiyoshi, and K. Sato. "Interfacial reactions and impact reliability of Sn–Zn solder joints on Cu or electroless Au/Ni(P) bond-pads." Journal of Materials Research 19, no. 10 (October 1, 2004): 2887–96. http://dx.doi.org/10.1557/jmr.2004.0371.

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Sn–9Zn and Sn–8Zn–3Bi solder balls were bonded to Cu or electroless Au/Ni(P)pads, and the effect of aging on joint reliability, including impact reliability, was investigated. For the purpose of quantitatively evaluating the impact toughness ofthe solder joints, a test similar to the classic Charpy impact test was performed.The interfacial compounds formed in the solder/Cu joint during soldering wereCu–Zn intermetallic compounds (IMCs), not Cu–Sn IMCs. One of the Cu–Zn IMCs, γ–Cu5Zn8, thickened remarkably with aging, and eventually its morphology changed from layer-type into discontinuous. The rapid growth of the γ–Cu5Zn8 and void formation at the bond interface led to the significant degradation of the joint reliability due to a ductile-to-brittle transition of the joint. Meanwhile, the compound formed in the solder/Au/Ni(P) joint during soldering was a Au–Zn IMC, above which Zn redeposited during aging. Both the dissolution and diffusion of Ni into the solders were extremely slow, which contributes to negligible void formation at the bond interface. As a result, the solder bumps on the Au/Ni(P) pads were able to maintain the high joint strength and impact toughness even after prolonged aging.

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Yang, Guang Yu. "Study of the Interfacial Reaction between the Sn-3.5Ag Solder and Electroless Ni-P Metallization." Applied Mechanics and Materials 441 (December 2013): 19–21. http://dx.doi.org/10.4028/www.scientific.net/amm.441.19.

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This work summarizes the interfacial reaction between lead-free solder Sn-3.5Ag and electrolessly plated Ni-P metallization in terms of morphology and growth kinetics of the intermetallic compounds (IMC). Comparison with pure Ni metallization is made in order to clarify the role of P in the solder reaction. During reflow, the IMCs formed with the Ni-P under-bump metallization (UBM) exist in chunky crystal blocks and small crystal agglomerates, while the ones with the sputtered Ni UBM exhibit uniformly scallop grains with faceted surfaces. The IMC thickness increases with reflow time following approximately a t^sup 1/3^ power law for both systems. The IMC growth rate is higher with the Ni-P UBM than the Ni UBM. The thickness of the Ni^sub 3^Sn^sub 4^ layer increases linearly with the square root of thermal aging time, indicating that the growth of the IMCs is a diffusion-controlled process. The activation energy for Ni^sub 3^Sn^sub 4^ growth in solid-state reaction is found to be 110 kJ/mol and 91 kJ/mol for the Ni-P and sputtered Ni UBMs, respectively. Kirkendall voids are detected inside the Ni^sub 3^P layer in the Sn-3.5AgTNi-P system. No such voids are found in the Sn-3.5AgTNi system.

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Min, Zhi Xian, Xiao Wu Hu, and Ying Xia Qiu. "Effects of Soldering Temperature on IMCs Formation between Sn-0.7Cu Solder and Cu Substrate." Applied Mechanics and Materials 713-715 (January 2015): 2685–88. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.2685.

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The interfacial reaction and growth of intermetallic compounds (IMCs) between the eutectic Sn-0.7 wt.% Cu solder and Cu substrate during soldering process were investigated experimentally. The Sn-0.7Cu/Cu couples were fabricated with soldering temperature varied at four levels of 300, 340 and 360°C. Microstructural analysis is conducted to analyze the IMCs thickness and morphology using scanning electron microscope. Two intermetallic phases were observed during soldering at the interface: η-phase (Cu6Sn5) and ε-phase (Cu3Sn) IMC layers, except for the solder joints which were fabricated at low temperature. The thickness of the η and ε IMC phases increase with increasing the soldering temperature. It’s found that the increase in total IMC layer thickness obeys a linear relationship with soldering temperature. And the relationship between X and T was given as X = 0.0866×T – 22.5 by means of linear fitting method.

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Sun, Feng Lian, Yang Liu, Yang Liu, Jia Bing Wang, and Hong Wu Zhang. "Improving Low-Ag Pb-Free Solder Performance by Adding Bi, Ni Elements." Advanced Materials Research 189-193 (February 2011): 3498–502. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.3498.

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In this study, some Ni, Bi elements were added into low-Ag (less than 1%) Sn-Ag-Cu (SAC) solder. The effect of these additive elements on the solderability, intermetallic compounds (IMCs), and electromigration performance of low-Ag SAC (LASAC) solder were investigated. With the increase of Bi content in LASAC-0.05Ni-xBi (x=0, 2.0, 2.5, 3.0, 3.5, 4.0) solders, the peak melting point decreases while the wetting area of solder alloy increases. With the addition of Ni, the IMC between Cu pad and LASAC solder transforms from Cu6Sn5 to (Cu1-xNix)6Sn5 and the morphology of the IMC turns from bulk-like to needle-like. Either the addition of Bi or Ni will slow down the IMCs growth rate during high temperature storage aging (HTS) at 180°C and has a positive effect on electromigration performance of LASAC soldering.

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Ogawa, Atsushi, Erito Mochiki, Mitsuhiro Yanai, Hiroki Morita, Yoshitaka Toyomasu, Kyoichi Ogata, Tetsuro Ohno, Takayuki Asao, and Hiroyuki Kuwano. "Interdigestive migrating contractions are coregulated by ghrelin and motilin in conscious dogs." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 302, no. 2 (January 15, 2012): R233—R241. http://dx.doi.org/10.1152/ajpregu.00078.2011.

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During fasting, gastrointestinal (GI) motility is characterized by cyclical motor contractions. These contractions have been referred to as interdigestive migrating contractions (IMCs). In dogs and humans, IMCs are known to be regulated by motilin. However, in rats and mice, IMCs are regulated by ghrelin. It is not clear how these peptides influence each other in vivo. The aim of the present study was to investigate the relationship between ghrelin and motilin in conscious dogs. Twenty healthy beagles were used in this study. Force transducers were implanted in the stomach, duodenum, and jejunum to monitor GI motility. Subsequent GI motility was recorded and quantified by calculating the motility index. In examination 1, blood samples were collected in the interdigestive state, and levels of plasma ghrelin and motilin were measured. Plasma motilin peaks were observed during every gastric phase III, and plasma ghrelin peaks occurred in nearly every early phase I. Plasma motilin and ghrelin levels increased and decreased cyclically with the interdigestive states. In examination 2, saline or canine ghrelin was administered intravenously during phase II and phase III. After injection of ghrelin, plasma motilin levels were measured. Ghrelin injection during phases II and III inhibited phase III contractions and decreased plasma motilin levels. In examination 3, ghrelin was infused in the presence of the growth hormone secretagogue receptors antagonist [d-Lys3]-GHRP-6. Continuous ghrelin infusion suppressed motilin release, an effect abrogated by the infusion of [d-Lys3]-GHRP-6. Examination 4 was performed to evaluate the plasma ghrelin response to motilin administration. Motilin infusion immediately decreased ghrelin levels. In this study, we demonstrated that motilin and ghrelin cooperatively control the function of gastric IMCs in conscious dogs. Our findings suggest that ghrelin regulates the function and release of motilin and that motilin may also regulate ghrelin.

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Jeong, Gyuwon, Dong-Yurl Yu, Seongju Baek, Junghwan Bang, Tae-Ik Lee, Seung-Boo Jung, JungSoo Kim, and Yong-Ho Ko. "Interfacial Reactions and Mechanical Properties of Sn–58Bi Solder Joints with Ag Nanoparticles Prepared Using Ultra-Fast Laser Bonding." Materials 14, no. 2 (January 11, 2021): 335. http://dx.doi.org/10.3390/ma14020335.

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The effects of Ag nanoparticle (Ag NP) addition on interfacial reaction and mechanical properties of Sn–58Bi solder joints using ultra-fast laser soldering were investigated. Laser-assisted low-temperature bonding was used to solder Sn–58Bi based pastes, with different Ag NP contents, onto organic surface preservative-finished Cu pads of printed circuit boards. The solder joints after laser bonding were examined to determine the effects of Ag NPs on interfacial reactions and intermetallic compounds (IMCs) and high-temperature storage tests performed to investigate its effects on the long-term reliabilities of solder joints. Their mechanical properties were also assessed using shear tests. Although the bonding time of the laser process was shorter than that of a conventional reflow process, Cu–Sn IMCs, such as Cu6Sn5 and Cu3Sn, were well formed at the interface of the solder joint. The addition of Ag NPs also improved the mechanical properties of the solder joints by reducing brittle fracture and suppressing IMC growth. However, excessive addition of Ag NPs degraded the mechanical properties due to coarsened Ag3Sn IMCs. Thus, this research predicts that the laser bonding process can be applied to low-temperature bonding to reduce thermal damage and improve the mechanical properties of Sn–58Bi solders, whose microstructure and related mechanical properties can be improved by adding optimal amounts of Ag NPs.

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Jeong, Gyuwon, Dong-Yurl Yu, Seongju Baek, Junghwan Bang, Tae-Ik Lee, Seung-Boo Jung, JungSoo Kim, and Yong-Ho Ko. "Interfacial Reactions and Mechanical Properties of Sn–58Bi Solder Joints with Ag Nanoparticles Prepared Using Ultra-Fast Laser Bonding." Materials 14, no. 2 (January 11, 2021): 335. http://dx.doi.org/10.3390/ma14020335.

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The effects of Ag nanoparticle (Ag NP) addition on interfacial reaction and mechanical properties of Sn–58Bi solder joints using ultra-fast laser soldering were investigated. Laser-assisted low-temperature bonding was used to solder Sn–58Bi based pastes, with different Ag NP contents, onto organic surface preservative-finished Cu pads of printed circuit boards. The solder joints after laser bonding were examined to determine the effects of Ag NPs on interfacial reactions and intermetallic compounds (IMCs) and high-temperature storage tests performed to investigate its effects on the long-term reliabilities of solder joints. Their mechanical properties were also assessed using shear tests. Although the bonding time of the laser process was shorter than that of a conventional reflow process, Cu–Sn IMCs, such as Cu6Sn5 and Cu3Sn, were well formed at the interface of the solder joint. The addition of Ag NPs also improved the mechanical properties of the solder joints by reducing brittle fracture and suppressing IMC growth. However, excessive addition of Ag NPs degraded the mechanical properties due to coarsened Ag3Sn IMCs. Thus, this research predicts that the laser bonding process can be applied to low-temperature bonding to reduce thermal damage and improve the mechanical properties of Sn–58Bi solders, whose microstructure and related mechanical properties can be improved by adding optimal amounts of Ag NPs.

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Cho, Moon Gi, Hwan Sik Lim, Sun Hee Park, Yong Hwan Kwon, Jaesik Chung, Jinho Choi, and Eun-Chul Ahn. "Optimization of Ag Composition in Cu Pillar Bumps with Sn-xAg Solders." International Symposium on Microelectronics 2012, no. 1 (January 1, 2012): 000906–11. http://dx.doi.org/10.4071/isom-2012-wp42.

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In order to minimize the large plate growth of Ag3Sn intermetallic compounds (IMCs) adversely affecting the mechanical behavior and reducing the reliability of solder joints, the Ag content of less than 3wt% has been suggested in ball grid array (BGA) Sn-Ag solders. The suggestion (< 3wt% Ag in the solders) is invalid in small solder bumps, and moreover there is no available guideline of the Ag content in the small Sn-Ag solders. In this study, the optimum level of Ag content in small Sn-Ag Cu pillar bumps (CPBs) of less than 50um in diameter was investigated to suppress the large plate growth of Ag3Sn. Since the undercooling of Sn-Ag solders increases with a decrease of solder ball size, the Ag3Sn IMCs are more prone to become largely plate-like in small solders. Actually, in small Sn-Ag CPBs, the large plate growth of Ag3Sn was observed on the top surface of solder bumps even though the Ag content was less than 3.0wt%. For suppression of Ag3Sn plates in Sn-Ag CPBs, two ways were suggested; increasing the cooling rate of the reflow profile and reducing the Ag content in the solders. Reducing the Ag content was effective on reducing the large plate growth of Ag3Sn, while a high cooling rate was not effective. Through the thermal analysis and thermodynamic calculations, the optimized Ag content in Sn-Ag CPBs of less than 50um was suggested, and the large plate growth of Ag3Sn was effectively reduced within the suggested Ag content.

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Wang, Jianxin, Hao Su, Dekui Mu, Xingda Kong, Yiming Jin, and Xixi Shi. "Growth behavior of IMCs in Sn–1.0Ag–0.5Cu–xBi/Ni joints during isothermal aging." Journal of Materials Science: Materials in Electronics 32, no. 15 (July 16, 2021): 20777–92. http://dx.doi.org/10.1007/s10854-021-06591-1.

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Mokhtar, N. Mohd, and Mohd Arif Anuar Mohd Salleh. "Sn Whiskers Nucleation and Growth - Short Review." Solid State Phenomena 280 (August 2018): 175–80. http://dx.doi.org/10.4028/www.scientific.net/ssp.280.175.

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Sn whisker growth on Cu substrate Pb-free solder is a serious problem in electric and electronic devices and as well as in aerospace applications. Due to the concern on the toxicity of lead by Restriction of Hazardous Substances Directive (RoHS), new lead free materials have been developed, and this resulted in the resurfacing of Sn whisker. The compressive stress, corrosionand surface oxide have been identified as the driving force for Sn whisker formation induced by mechanical alloying and oxidation. In this paper, we report the study to understand the mechanism of Sn whisker growth that control whisker formation on Sn finished.Based on the review, a preliminary conclusion has been made, where the analysis of the topography and microstructural characterization can be determined by evaluating under various environmental influences.Furthermore, the whisker growth happening on lead-free soldered can be considerably reduced by controlling the compressive stress in the solder which initiates the growth of intermetallic compounds (IMCs).

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Tian, Ye, Ning Ren, Zhihua Zhao, Fengshun Wu, and Suresh Sitaraman. "Ag3Sn Compounds Coarsening Behaviors in Micro-Joints." Materials 11, no. 12 (December 10, 2018): 2509. http://dx.doi.org/10.3390/ma11122509.

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As solder joints are being scaled down, intermetallic compounds (IMCs) are playing an increasingly critical role in the reliability of solder joints, and thereby an in-depth understanding of IMCs microstructure evolutions in micro-joints is of great significance. This study focused on coarsening behaviors of Ag3Sn compounds in Sn-3.0Ag-0.5Cu (SAC305) micro-joints of flip chip assemblies using thermal shock (TS) tests. The results showed that the Ag3Sn compounds grew and rapidly coarsened into larger ones as TS cycles increased. Compared with such coarsening behaviors during thermal aging, TS exhibited a significantly accelerating influence. This predominant contribution is quantitatively determined to be induced by strain-enhanced aging. Moreover, based on observations for Ag3Sn microstructure evolutions during TS cycling, one particular finding showed that there are two types of coarsening modes (i.e., Ostwald ripening and Necking coalescence) co-existing in the Ag3Sn coarsening process. The corresponding evolutions mechanism was elucidated in a combination of simulative analysis and experimental validation. Furthermore, a kinetic model of the Ag3Sn coarsening was established incorporating static aging and strain-enhanced aging constant, the growth exponent (n) was calculated to be 1.70, and the predominant coarsening mode was confirmed to be the necking coalescence.

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Tian, Yee Kai, and Mee Chu Wong. "Interfacial Morphology Studies of Sn-3.8Ag-0.7Cu Alloy on Different Substrates." Advanced Materials Research 686 (April 2013): 201–10. http://dx.doi.org/10.4028/www.scientific.net/amr.686.201.

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Since the ban of lead containing solders, eutectic SAC solders has been claimed to posses better properties compared to other series of lead free solders. As the technology trend for portable devices change over time, solder joints are continuously miniaturized. The VLSI in modern devices will subject the solder joints to repeated temperature cycling during both assembling and use due to higher I/O. These lead free solders are prone to excessive intermetallic compound (IMC) growth at the interface between the solder and the substrate due to the reasons cited earlier. The most common substrate used in electronic packaging is Cu while Au or its alloys are often used as metallization layer. In this study PCBs coated with both Cu and Au to study the interfacial morphology of Sn-3.8Ag-0.7Cu (SAC387) alloy with these metals. SEM imaging and EDX analysis were used to observe the interfacial layers and to confirm formation of IMCs. IMCs formed between Au-solder are more blocky-like compared to those formed between Cu-solder. Thus further studies must be conducted to resolve this issue as Au is a commonly used metallization materials.

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Hu, Xiaowu, Chao Li, Qinglin Li, and Guangbin Yi. "Insights on interfacial IMCs growth and mechanical strength of asymmetrical Cu/SAC305/Cu-Co system." Vacuum 167 (September 2019): 77–89. http://dx.doi.org/10.1016/j.vacuum.2019.05.044.

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Yang, Li, Lu Zhu, Yaocheng Zhang, Shiyuan Zhou, Yifeng Xiong, and Pengcheng Wu. "Microstructural evolution and IMCs growth behavior of Sn-58Bi-0.25Mo solder joint during aging treatment." Materials Research Express 5, no. 2 (February 21, 2018): 026304. http://dx.doi.org/10.1088/2053-1591/aaad71.

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Kang, Tian You, Yu Yan Xiu, Bo Xu, Chun Zhong Liu, and Wei Ping Tong. "Effect of Ni Addition on the Formation and Growth of Intermetallic Compound at Eutectic SnBi/Cu Interface." Advanced Materials Research 160-162 (November 2010): 709–14. http://dx.doi.org/10.4028/www.scientific.net/amr.160-162.709.

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The reactions between Cu and the eutectic SnBi (Sn58wt.%Bi) solder alloy with and without 1wt.%Ni addition were investigated in this paper. After as-reflowed process, the IMCs formed in the Sn58wt.%Bi/Cu and Sn58wt.%Bi1wt.%Ni/Cu joints were Cu6Sn5 and (CuNi)6Sn5, respectively. During aging process, the thickness of the IMC layers formed at each solder/Cu joint increased, and a new layer Cu3Sn formed adjacent to the Cu substrate. It was found that 1wt.%Ni addition in Sn58wt.%Bi solder alloy could slightly enhance the growth rate of the total IMC layer, but effectively reduce the growth rate of Cu3Sn layer during aging process. The growth behavior of IMC layer for each joint followed the diffusion-controlled mechanism during aging.

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Henriques, Ana, Vasiliki Koliaraki, and George Kollias. "Mesenchymal MAPKAPK2/HSP27 drives intestinal carcinogenesis." Proceedings of the National Academy of Sciences 115, no. 24 (May 29, 2018): E5546—E5555. http://dx.doi.org/10.1073/pnas.1805683115.

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Mesenchymal cells in the microenvironment of cancer exert important functions in tumorigenesis; however, little is known of intrinsic pathways that mediate these effects. MAPK signals, such as from MAPKAPK2 (MK2) are known to modulate tumorigenesis, yet their cell-specific role has not been determined. Here, we studied the cell-specific role of MK2 in intestinal carcinogenesis using complete and conditional ablation of MK2. We show that both genetic and chemical inhibition of MK2 led to decreased epithelial cell proliferation, associated with reduced tumor growth and invasive potential in the Apcmin/+ mouse model. Notably, this function of MK2 was not mediated by its well-described immunomodulatory role in immune cells. Deletion of MK2 in intestinal mesenchymal cells (IMCs) led to both reduced tumor multiplicity and growth. Mechanistically, MK2 in IMCs was required for Hsp27 phosphorylation and the production of downstream tumorigenic effector molecules, dominantly affecting epithelial proliferation, apoptosis, and angiogenesis. Genetic ablation of MK2 in intestinal epithelial or endothelial cells was less effective in comparison with its complete deletion, leading to reduction of tumor size via modulation of epithelial apoptosis and angiogenesis-associated proliferation, respectively. Similar results were obtained in a model of colitis-associated carcinogenesis, indicating a mesenchymal-specific role for MK2 also in this model. Our findings demonstrate the central pathogenic role of mesenchymal-specific MK2/Hsp27 axis in tumorigenesis and highlight the value of mesenchymal MK2 inhibition in the treatment of cancer.

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Naknaen, Ampapan, Waraporn Ratsameepakai, Oramas Suttinun, Yaowapa Sukpondma, Eakalak Khan, and Rattanaruji Pomwised. "Microcystis Sp. Co-Producing Microcystin and Saxitoxin from Songkhla Lake Basin, Thailand." Toxins 13, no. 9 (September 8, 2021): 631. http://dx.doi.org/10.3390/toxins13090631.

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The Songkhla Lake Basin (SLB) located in Southern Thailand, has been increasingly polluted by urban and industrial wastewater, while the lake water has been intensively used. Here, we aimed to investigate cyanobacteria and cyanotoxins in the SLB. Ten cyanobacteria isolates were identified as Microcystis genus based on16S rDNA analysis. All isolates harbored microcystin genes, while five of them carried saxitoxin genes. On day 15 of culturing, the specific growth rate and Chl-a content were 0.2–0.3 per day and 4 µg/mL. The total extracellular polymeric substances (EPS) content was 0.37–0.49 µg/mL. The concentration of soluble EPS (sEPS) was 2 times higher than that of bound EPS (bEPS). The protein proportion in both sEPS and bEPS was higher than the carbohydrate proportion. The average of intracellular microcystins (IMCs) was 0.47 pg/cell on day 15 of culturing, while extracellular microcystins (EMCs) were undetectable. The IMCs were dramatically produced at the exponential phase, followed by EMCs release at the late exponential phase. On day 30, the total microcystins (MCs) production reached 2.67 pg/cell. Based on liquid chromatograph-quadrupole time-of-flight mass spectrometry, three new MCs variants were proposed. This study is the first report of both decarbamoylsaxitoxin (dcSTX) and new MCs congeners synthesized by Microcystis.

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Kuo, Shih-Ming, and Kwang-Lung Lin. "Polarity effect of electromigration on intermetallic compound formation in a Cu/Sn–9Zn/Cu sandwich." Journal of Materials Research 23, no. 4 (April 2008): 1087–94. http://dx.doi.org/10.1557/jmr.2008.0142.

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This study investigated the polarity effect of electromigration (EM) on the interfacial intermetallic compounds (IMCs) (γ-Cu5Zn8, Cu6Sn5) formation at the anode and the cathode in a Cu/Sn-9Zn/Cu sandwich with a constant direct current density of 1.0 × 103 A/cm2 at 100 °C. The EM had different polarity effects on the nucleation and growth rates of the interfacial Cu5Zn8 IMC from those of Cu6Sn5 IMC. Upon current stressing, the growth rate of the Cu-Zn intermetallic compound (γ-Cu5Zn8) at the cathode interface was much faster than that at the anode. However, the nucleation and growth of the Cu6Sn5 IMC at the anode interface were enhanced, though retarded at the cathode, under the influence of electric current. The mechanism of EM-induced Cu6Sn5 IMC formation towards the anodic Cu is also discussed.

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Hu, Xiaowu, Tao Xu, Xiongxin Jiang, and Yulong Li. "Interfacial reaction and IMCs growth behavior of Sn3Ag0.5Cu/Ni solder bump during aging at various temperatures." Journal of Materials Science: Materials in Electronics 27, no. 5 (January 8, 2016): 4245–52. http://dx.doi.org/10.1007/s10854-016-4288-9.

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Journal articles on the topic 'Growth of IMCs'

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