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Xu Chen - One of the best experts on this subject based on the ideXlab platform.
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three dimensional visualization of the crack growth behavior of nano Silver joints during shear creep
Journal of Electronic Materials, 2015Co-Authors: Yansong Tan, Yun Hui Mei, Gang Chen, Xu ChenAbstract:Evolution of creep damage in nano-Silver sintered lap shear joints was investigated at 325C. Non-destructive x-ray three-dimensional (3D) visualization clearly revealed the crack-growth behavior of the joint; this could be divided into three stages. In the initial stage, little development of cracks occurred. In the second stage, cracks propagated at a consistent rate. In the final stage, rapid extension of the cracks led directly to fracture of the joint. Three-dimensional volume-rendered images and fractographic analysis showed that the growth of macroscopic initial cracks at the interfaces dominated the creep fracture process. Initial failure of nano-Silver sintered lap shear joints often occurred at interfacial nano-Silver Paste layers. Both the size and position of the initial interfacial cracks had significant effects on the final creep failure of the joints, and higher stresses led to greater porosity and earlier failure.
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high temperature ratcheting behavior of nano Silver Paste sintered lap shear joint under cyclic shear force
Microelectronics Reliability, 2013Co-Authors: Gang Chen, Xu Chen, Lei Wang, Yun Hui MeiAbstract:Abstract Low temperature sintered nano-Silver Paste can be used for connected chips that require high temperature operation and high heat dissipate ability because of its higher melting temperature, and better thermal/electrical conductivity than conventional solders and adhesive films. In this study, high temperature ratcheting behavior of the nano-Silver Paste sintered lap shear joint was examined by cyclic shear force at room temperature and elevated temperatures at 225 °C, 275 °C and 325 °C. The effects of shear stress amplitude, mean shear stress, peak stress dwell time and temperature on the ratcheting response of sintered lap shear joint were analyzed. Results show that (1) the ratcheting strain and ratcheting strain rate of the nano-Silver sintered lap shear joint increase with increasing shear stress amplitude or mean shear stress; (2) the ratcheting strain increases with the increasing temperature or the peak stress dwell time; (3) the ratcheting strain shakes down after it accumulates to a certain extent at room temperature; (4) even though 225 °C is a destructive temperature for solder and adhesive films, the ratcheting evolution of nano-Silver sintered joint is very mild no matter whether the sample dwells at peak stress or not; (5) the influence of shear stress amplitude, mean shear stress or peak stress dwell time is more and more obvious at high temperatures.
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Creep properties of low-temperature sintered nano-Silver lap shear joints
Materials Science and Engineering: A, 2013Co-Authors: Gang Chen, Yun Hui Mei, Lei Wang, Xu ChenAbstract:Abstract As a potential alternative to conventional solders and adhesive films, low-temperature sintered nano-Silver Paste, as a result of its high thermal and electrical conductivity (240 W m−1 K−1 and 4.1×107 S m−1, respectively) and high melting temperature (961 °C), can be used for connecting chips that require high temperature operation and high heat dissipation ability. In the present work, a number of creep tests were carried out to study the effect of stress and temperature on the creep behavior of low-temperature sintered nano-Silver lap shear joints. The steady-state creep flow behavior of the joints was discussed. In general, the creep shear strain rate increased as the applied stress and ambient temperature increased. When the creep strain rate was described by the Arrhenius power-law model, we found that the stress exponent and activation energy were temperature dependent and stress dependent, respectively. A modified power-law model with a temperature-dependent stress exponent and stress-dependent activation energy was proposed to describe accurately the creep flow of the sintered lap shear joints.
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mechanical property evaluation of nano Silver Paste sintered joint using lap shear test
Soldering & Surface Mount Technology, 2012Co-Authors: Gang Chen, Xu Chen, Yun Hui MeiAbstract:Purpose – The purpose of this paper is to evaluate the mechanical properties of nano‐Silver Paste sintered lap shear structures and to discuss the effects of loading rate and ambient temperature on shear strength and fracture mechanism.Design/methodology/approach – Single lap shear joints with an area of 2 mm2 and thickness of 50 μm were fabricated by joining two copper substrates with nano‐Silver Paste. The lap shear tests were carried out under strain control mode on a micro uniaxial fatigue testing system with four loading rates and temperatures. The fracture sections were analyzed by SEM observation to determine the effect of temperature on the fracture mechanism.Findings – Results from the study highlighted that the shear strain rate and temperature can have a significant impact on the shear behaviour of nano‐Silver Paste sintered lap shear joints. The shear strength increased with shear strain rate, but decreased with increasing ambient temperature. The lap shear joints displayed excellent ductility...
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migration of sintered nanoSilver die attach material on alumina substrate between 250 circ hbox c and 400 circ hbox c in dry air
IEEE Transactions on Device and Materials Reliability, 2011Co-Authors: Yun Hui Mei, Xu Chen, Shu Fang Luo, Dimeji IbitayoAbstract:The low-temperature joining of semiconductor chips by sintering of Silver Paste is emerging as an alternative lead-free solution for power electronics devices and modules working in a high-temperature environment. A promising die-attachment material that would enable the rapid implementation of the sintering process is nanoscale Silver Paste, which can be sintered at temperatures below 300°C without an external pressure. In this paper, we report our findings on the Silver migration in sintered nanoSilver electrode-pair patterns on an alumina substrate. The electrode pairs were biased at an electric field ranging from 10 to 100 V/mm and at a temperature between 250°C and 400°C in dry air. The leakage currents across the electrodes were measured as the Silver patterns were tested in an oven. Silver dendrites formed across the electrode gap were observed under an optical microscope and analyzed using scanning electron microscopy and energy dispersive spectroscopy (EDS). The Silver migration was found in the samples tested at 400°C, 350°C, 300°C, and 250°C. The measurements on the leakage current versus time were characterized by an initial incubation period, called “lifetime,” followed by a sharp rise as the Silver dendrites were shorting the electrodes. A simple phenomenological model was derived to account for the observed dependence of lifetime on the electric field and temperature. The EDS mappings revealed the significant presence of oxygen on the positive electrode but the complete absence on the negative electrode. A mechanism involving the oxidation of Silver and the dissociation of Silver oxide at the anode was suggested. We suggest that the migration of a sintered nanoSilver die attachment can be prevented in high-temperature applications through packaging or encapsulation to reduce the partial pressure of oxygen.
Yun Hui Mei - One of the best experts on this subject based on the ideXlab platform.
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Tailoring a Silver Paste for Additive Manufacturing of Co-Fired Ferrite Magnetic Components
Materials (Basel Switzerland), 2019Co-Authors: Lanbing Liu, Chao Ding, Yun Hui MeiAbstract:Additive manufacturing (AM), or 3D-printing, has the potential for rapid prototyping of innovative designs of magnetic components used in power electronics converters. In this study, we tailored a Silver Paste as the metal feedstock of an extrusion 3D printer so that the metal would be compatible with a ferrite Paste feedstock for 3D-printing of ferrite magnetic components. We focused on adjusting the metal formulation to match its shrinkage to that of the ferrite and to improve adhesion during the co-sintering process of the printed part. We found that a 5 wt % addition of ferrite powder in the metal Paste can achieve matched shrinkage and strong adhesion. Evaluation of the co-sintered magnetic components showed no significant defects, such as cracks, warpage, or delamination, between the metal and ferrite. The shear strength between the two sintered materials was greater than 50 MPa, and the electrical resistivity of the sintered metal winding was less than twice that of the bulk Silver, which is lower than those of most 3D-printed winding metals reported in the literature.
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A novel multiscale Silver Paste for die bonding on bare copper by low-temperature pressure-free sintering in air
Materials and Design, 2018Co-Authors: Jie Li, Xin Li, Lei Wang, Yun Hui MeiAbstract:NanoSilver sintering is expected to overcome the limitation of relatively high production cost and become widely available for the die bonding of power electronics. A potential application of nanoSilver sintering is bare copper bonding, where replacing substrates with auxiliary Silver or other plating that can damage bonding would be advantageous. Here, we introduce a novel multiscale Silver Paste containing both nanoparticles (20–100 nm) and microparticles (1–5 μm) for the bonding of high-power chips on a bare copper substrate by pressure-free sintering in air. The energy potential difference generated in the surface force field was critical in the formation of sintering necks between the nano and microparticles, which, together with other microparticles, formed the high-density sintered structure. Despite the development of a copper oxide film, the interfacial bonding was comparable to or higher than the sintering force due to the high surface energy of porous sintered structure and easy diffusion of nanoparticles occurred. A processing temperature of 265 °C was considered optimal for bare copper joint (shear strength: 53 MPa, transient thermal impedance: 0.132 °C/W) considering the trade-off between achieving excellent mechanical and thermal properties while minimizing oxidation.
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Enhanced pressureless bonding by Tin Doped Silver Paste at low sintering temperature
Materials Science and Engineering A, 2016Co-Authors: Cheng-xiang Yang, Xin Li, Yun Hui MeiAbstract:The nanoSilver sintering die-attach technique has been a promising alternative for wide band gap semiconductors. However, it is less preferable in industry because of its high sintering temperature. Recently research has been initiated to develop transient liquid phase sintering (TLPS) solder Paste for use in electronics packaging. In this article, in order to lower the sintering temperature of nanoSilver Paste, we develop a novel tin (up to 10 wt%) doped Silver Paste (TDSP) and a sintering profile with the highest processing temperature of 235 °C based on TLPS. Sintered TDSP is Ag/Ag3Sn/Ag-Sn solid solution composites. The composites have a microstructure of Ag matrix grains reinforced by Ag3Sn and Ag-Sn solid solution within the matrix grains. And this microstructure endows the sintered Ag+4%Sn with a pressureless bonding strength of 23 MPa. The improved mechanical properties of sintered TDSP are attributed to second-phase strengthening and solid solution strengthening mechanisms. However, the overmuch formation of brittle Ag3Sn phase is the main reason resulting in sharp decrease of bonding strength when the Sn content over 5 wt%. The new TDSP technology is expected to be applicable to a wide range of power semiconductors devices, such as organic devices and printed circuit boards. Furthermore, it provides new strategies for low-temperature sintering.
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three dimensional visualization of the crack growth behavior of nano Silver joints during shear creep
Journal of Electronic Materials, 2015Co-Authors: Yansong Tan, Yun Hui Mei, Gang Chen, Xu ChenAbstract:Evolution of creep damage in nano-Silver sintered lap shear joints was investigated at 325C. Non-destructive x-ray three-dimensional (3D) visualization clearly revealed the crack-growth behavior of the joint; this could be divided into three stages. In the initial stage, little development of cracks occurred. In the second stage, cracks propagated at a consistent rate. In the final stage, rapid extension of the cracks led directly to fracture of the joint. Three-dimensional volume-rendered images and fractographic analysis showed that the growth of macroscopic initial cracks at the interfaces dominated the creep fracture process. Initial failure of nano-Silver sintered lap shear joints often occurred at interfacial nano-Silver Paste layers. Both the size and position of the initial interfacial cracks had significant effects on the final creep failure of the joints, and higher stresses led to greater porosity and earlier failure.
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Study on high temperature bonding reliability of sintered nano-Silver joint on bare copper plate
Microelectronics Reliability, 2015Co-Authors: Su Yan Zhao, Xin Li, Yun Hui MeiAbstract:Nano-Silver Paste has become an alternative lead-free (Pb-free) die attach material for microelectronic packaging, compared to traditional solders and adhesive films, due to its higher thermal and electrical conductivity, higher temperature operation and higher heat dissipation. In this study, the reliable joints of sintered nano-Silver Paste on bare copper plate with large-area dummy chips were introduced and thermally aged at 150 °C, 180 °C, or even higher than 250 °C in air or in a coarse vacuum environment. The bonding strength and interfacial reaction were investigated. The results showed, after aging specimens at 150 °C for 960 h in air or at 250 °C for 960 h in a coarse vacuum, the interfaces between the sintered nano-Silver and bare copper still consisted of simple inter-diffusion bands and with almost no change in bonding strength. However, the bonding strength sharply decreased to 50% after aging at 180 °C for 72 h in air and it decreased to 20% after aging at 250 °C for 72 h in air. The decrease in bonding strength was mainly attributed to the oxidation of copper at relative elevated temperature in this work.
Gang Chen - One of the best experts on this subject based on the ideXlab platform.
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three dimensional visualization of the crack growth behavior of nano Silver joints during shear creep
Journal of Electronic Materials, 2015Co-Authors: Yansong Tan, Yun Hui Mei, Gang Chen, Xu ChenAbstract:Evolution of creep damage in nano-Silver sintered lap shear joints was investigated at 325C. Non-destructive x-ray three-dimensional (3D) visualization clearly revealed the crack-growth behavior of the joint; this could be divided into three stages. In the initial stage, little development of cracks occurred. In the second stage, cracks propagated at a consistent rate. In the final stage, rapid extension of the cracks led directly to fracture of the joint. Three-dimensional volume-rendered images and fractographic analysis showed that the growth of macroscopic initial cracks at the interfaces dominated the creep fracture process. Initial failure of nano-Silver sintered lap shear joints often occurred at interfacial nano-Silver Paste layers. Both the size and position of the initial interfacial cracks had significant effects on the final creep failure of the joints, and higher stresses led to greater porosity and earlier failure.
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high temperature ratcheting behavior of nano Silver Paste sintered lap shear joint under cyclic shear force
Microelectronics Reliability, 2013Co-Authors: Gang Chen, Xu Chen, Lei Wang, Yun Hui MeiAbstract:Abstract Low temperature sintered nano-Silver Paste can be used for connected chips that require high temperature operation and high heat dissipate ability because of its higher melting temperature, and better thermal/electrical conductivity than conventional solders and adhesive films. In this study, high temperature ratcheting behavior of the nano-Silver Paste sintered lap shear joint was examined by cyclic shear force at room temperature and elevated temperatures at 225 °C, 275 °C and 325 °C. The effects of shear stress amplitude, mean shear stress, peak stress dwell time and temperature on the ratcheting response of sintered lap shear joint were analyzed. Results show that (1) the ratcheting strain and ratcheting strain rate of the nano-Silver sintered lap shear joint increase with increasing shear stress amplitude or mean shear stress; (2) the ratcheting strain increases with the increasing temperature or the peak stress dwell time; (3) the ratcheting strain shakes down after it accumulates to a certain extent at room temperature; (4) even though 225 °C is a destructive temperature for solder and adhesive films, the ratcheting evolution of nano-Silver sintered joint is very mild no matter whether the sample dwells at peak stress or not; (5) the influence of shear stress amplitude, mean shear stress or peak stress dwell time is more and more obvious at high temperatures.
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Creep properties of low-temperature sintered nano-Silver lap shear joints
Materials Science and Engineering: A, 2013Co-Authors: Gang Chen, Yun Hui Mei, Lei Wang, Xu ChenAbstract:Abstract As a potential alternative to conventional solders and adhesive films, low-temperature sintered nano-Silver Paste, as a result of its high thermal and electrical conductivity (240 W m−1 K−1 and 4.1×107 S m−1, respectively) and high melting temperature (961 °C), can be used for connecting chips that require high temperature operation and high heat dissipation ability. In the present work, a number of creep tests were carried out to study the effect of stress and temperature on the creep behavior of low-temperature sintered nano-Silver lap shear joints. The steady-state creep flow behavior of the joints was discussed. In general, the creep shear strain rate increased as the applied stress and ambient temperature increased. When the creep strain rate was described by the Arrhenius power-law model, we found that the stress exponent and activation energy were temperature dependent and stress dependent, respectively. A modified power-law model with a temperature-dependent stress exponent and stress-dependent activation energy was proposed to describe accurately the creep flow of the sintered lap shear joints.
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mechanical property evaluation of nano Silver Paste sintered joint using lap shear test
Soldering & Surface Mount Technology, 2012Co-Authors: Gang Chen, Xu Chen, Yun Hui MeiAbstract:Purpose – The purpose of this paper is to evaluate the mechanical properties of nano‐Silver Paste sintered lap shear structures and to discuss the effects of loading rate and ambient temperature on shear strength and fracture mechanism.Design/methodology/approach – Single lap shear joints with an area of 2 mm2 and thickness of 50 μm were fabricated by joining two copper substrates with nano‐Silver Paste. The lap shear tests were carried out under strain control mode on a micro uniaxial fatigue testing system with four loading rates and temperatures. The fracture sections were analyzed by SEM observation to determine the effect of temperature on the fracture mechanism.Findings – Results from the study highlighted that the shear strain rate and temperature can have a significant impact on the shear behaviour of nano‐Silver Paste sintered lap shear joints. The shear strength increased with shear strain rate, but decreased with increasing ambient temperature. The lap shear joints displayed excellent ductility...
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Uniaxial ratcheting and fatigue behaviors of low-temperature sintered nano-scale Silver Paste at room and high temperatures
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Tao Wang, Gang Chen, Yanping Wang, Xu ChenAbstract:Uniaxial ratcheting and fatigue behaviors of low-temperature sintered Silver films at room and high temperatures were studied experimentally and particular attention was paid to the influence of ratcheting to fatigue. The effects of stress amplitude, mean stress, stress rate, temperature, peak stress holding time and loading history on the ratcheting response of sintered Silver films were analyzed, respectively. Firstly, it can be concluded that the ratcheting strain amplitude and ratcheting strain rate of the material increase with increasing stress amplitude or mean stress, correspondingly. Secondly, the experimental results indicate that ratcheting strain increases significantly with the increasing temperature and decreasing stress rate. Thirdly, the material was found having a strong memorization on loading history, the prior stress cycling with low stress amplitude or mean stress can greatly retard the strain accumulation under subsequent loading conditions. Fourthly, the strain accumulation with peak stress holding time is larger than that without hold time at high temperatures, but the ratcheting evolution with and without hold time is almost equal at room temperature. Finally, it was found that the fatigue failure of sintered Silver Paste is dominated by ratcheting response especially for high temperature and long peak stress holding time. The factors such as stress rate, temperature and peak stress holding time also have a significant influence on fatigue life since they all greatly affected ratcheting behavior of the material.
Kat Suaki Suganuma - One of the best experts on this subject based on the ideXlab platform.
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enhancing low temperature and pressureless sintering of micron Silver Paste based on an ether type solvent
Journal of Electronic Materials, 2017Co-Authors: Hao Zhang, Jin-ting Jiu, Yue Gao, Kat Suaki SuganumaAbstract:Micron Silver Paste enables a low-temperature and pressureless sintering process by using an ether-type solvent CELTOL-IA (C x H y O z , x > 10, boiling point of approximately 200°C) for the die attachment of high-powered devices. The conductive patterns formed by the Silver Paste had a low electrical resistivity of 8.45 μΩ cm at 180°C. The Paste also achieved a high bonding strength above 30 MPa at 180°C without the assistance of pressures. These superior performance indicators result from the favorable removal of the solvent, its thermal behavior, and its good wetting on the Silver layer. The results suggest that the micron Silver Paste with a suitable␣solvent can promote the further spreading of next-generation power devices owing to its marked cost advantage and excellent performance.
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In situ bridging effect of Ag2O on pressureless and low-temperature sintering of micron-scale Silver Paste
Journal of Alloys and Compounds, 2017Co-Authors: Hao Zhang, Jin-ting Jiu, Yue Gao, Kat Suaki SuganumaAbstract:Silver sintering joining technology provides lead-free die attachment with excellent thermal conductivity and compatibility with high-temperature (≥300 °C) applications. However, sintering affordable micron-scale Silver particles requires high temperature and the assistance of high pressures, which can damage chips and increase the manufacturing cost. In this article, we achieved the low-temperature, pressureless sintering of micron-scale Silver particles by employing an active Ag2O additive as a bridge among the micron-scale Silver particles. The Ag2O was reduced in situ to nanoscale Silver to activate the surface of the micron-scale Silver particles, resulting in the rapid diffusion and densification of Silver particles at low temperature. An optimized composition of Ag-10% Ag2O exhibited a bonding strength of over 40 MPa at only 180 °C without any additional pressure. The results suggest that affordable micron-scale metal particles can be sintered using a suitable activating additive under an energy-efficient and eco-friendly fabrication process.
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die attaching Silver Paste based on a novel solvent for high power semiconductor devices
Journal of Materials Science, 2016Co-Authors: Jin-ting Jiu, Hao Zhang, Shijo Nagao, Tohru Sugahara, Noriko Kagami, Youji Suzuki, Yasuyuki Akai, Kat Suaki SuganumaAbstract:A new solvent composed of 4-(tert-butyl) cyclohexyl acetate as a dilute agent and HPMDA as a thickener was developed to make micron-sized Ag Paste and to bond power semiconductors. The new Ag Paste achieved sentinel printing to form sharp Ag patterns with uniform thickness and defined boundaries, which is a key to printing fine pitches in the electronics industry. The electrical resistivity of Ag patterns of 3 μΩ cm was obtained at 280 °C for 30 min. Two Ag-plating copper substrates were successfully bonded with the new Ag Paste and the shear strength gradually increased with the bonding temperature. A high strength of 80 MPa was achieved at 280 °C under a small sintering pressure of 0.4 MPa. This value is far higher than the value obtained by using an expensive Ag nanoparticle Paste. The detailed mechanism is discussed in this work by comparison with common ethylene glycol solvent.
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New Silver Paste for Die-Attaching Ceramic Light-Emitting Diode Packages
IEEE Transactions on Components Packaging and Manufacturing Technology, 2011Co-Authors: Masafumi Kuramoto, Satoru Ogawa, Miki Niwa, Keun-soo Kim, Kat Suaki SuganumaAbstract:Micrometer-sized Ag particles adsorb substantial oxygen above 200°C and a dispersion of these particles in alcohol can be successfully used as a die-attach material by sintering to form a soft porous bonding layer. The characteristics of a light-emitting diode (LED) using this Ag Paste as a die-attach material were evaluated. The LED was assembled on an alumina ceramic package, which did not degrade upon sintering, with a sapphire-based InGaN LED die. The bonding strength was twice as high to the ceramic package as to a copper alloy lead frame. Thus, the Ag Paste is suitable for use with LED ceramic packages as a bonding material. In addition, a significant reduction of the thermal resistance and improvement of the reliability are achieved by using the Ag sintered layer for die-attaching the ceramic LED package. To improve the bond reliability between sapphire and alumina, both of which are low-thermal-expansion materials, the thermal expansion of the Ag sintered layer was reduced by the addition of Kovar particles. The addition of Kovar particles, with or without Ag plating, to Ag particles exhibited a desirable effect. The present mounting method for LEDs was proved to be useful for die-bonding electronic components, providing an alternative technique to high-temperature high-lead soldering.
Hao Zhang - One of the best experts on this subject based on the ideXlab platform.
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enhancing low temperature and pressureless sintering of micron Silver Paste based on an ether type solvent
Journal of Electronic Materials, 2017Co-Authors: Hao Zhang, Jin-ting Jiu, Yue Gao, Kat Suaki SuganumaAbstract:Micron Silver Paste enables a low-temperature and pressureless sintering process by using an ether-type solvent CELTOL-IA (C x H y O z , x > 10, boiling point of approximately 200°C) for the die attachment of high-powered devices. The conductive patterns formed by the Silver Paste had a low electrical resistivity of 8.45 μΩ cm at 180°C. The Paste also achieved a high bonding strength above 30 MPa at 180°C without the assistance of pressures. These superior performance indicators result from the favorable removal of the solvent, its thermal behavior, and its good wetting on the Silver layer. The results suggest that the micron Silver Paste with a suitable␣solvent can promote the further spreading of next-generation power devices owing to its marked cost advantage and excellent performance.
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In situ bridging effect of Ag2O on pressureless and low-temperature sintering of micron-scale Silver Paste
Journal of Alloys and Compounds, 2017Co-Authors: Hao Zhang, Jin-ting Jiu, Yue Gao, Kat Suaki SuganumaAbstract:Silver sintering joining technology provides lead-free die attachment with excellent thermal conductivity and compatibility with high-temperature (≥300 °C) applications. However, sintering affordable micron-scale Silver particles requires high temperature and the assistance of high pressures, which can damage chips and increase the manufacturing cost. In this article, we achieved the low-temperature, pressureless sintering of micron-scale Silver particles by employing an active Ag2O additive as a bridge among the micron-scale Silver particles. The Ag2O was reduced in situ to nanoscale Silver to activate the surface of the micron-scale Silver particles, resulting in the rapid diffusion and densification of Silver particles at low temperature. An optimized composition of Ag-10% Ag2O exhibited a bonding strength of over 40 MPa at only 180 °C without any additional pressure. The results suggest that affordable micron-scale metal particles can be sintered using a suitable activating additive under an energy-efficient and eco-friendly fabrication process.
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die attaching Silver Paste based on a novel solvent for high power semiconductor devices
Journal of Materials Science, 2016Co-Authors: Jin-ting Jiu, Hao Zhang, Shijo Nagao, Tohru Sugahara, Noriko Kagami, Youji Suzuki, Yasuyuki Akai, Kat Suaki SuganumaAbstract:A new solvent composed of 4-(tert-butyl) cyclohexyl acetate as a dilute agent and HPMDA as a thickener was developed to make micron-sized Ag Paste and to bond power semiconductors. The new Ag Paste achieved sentinel printing to form sharp Ag patterns with uniform thickness and defined boundaries, which is a key to printing fine pitches in the electronics industry. The electrical resistivity of Ag patterns of 3 μΩ cm was obtained at 280 °C for 30 min. Two Ag-plating copper substrates were successfully bonded with the new Ag Paste and the shear strength gradually increased with the bonding temperature. A high strength of 80 MPa was achieved at 280 °C under a small sintering pressure of 0.4 MPa. This value is far higher than the value obtained by using an expensive Ag nanoparticle Paste. The detailed mechanism is discussed in this work by comparison with common ethylene glycol solvent.