EMSNow - Indium Corporation Technology Expert to Present at IMAPS Advanced Technology Workshop: Indium Corporation's Brook Sandy-Smith, Product Support Specialist - PCB Assembly Materials, will present at the International Microelectronics and Packaging Society (IMAPS) Advanced Technology Workshop on Microelectronic Packaging for Medical and Hi-Reliability Devices May 13-14 in Minneapolis,
Sandy-Smith will present the following papers:
• A Low-Silver SAC Solder Alloy for High-Reliability Applications. This presentation examines the reliability of a low-Ag SAC solder alloy doped with Mn (SACM). SACM is compared to eutectic SnPb, SAC105, SAC305 alloys under various test conditions, such as JEDEC drop shock, dynamic bending, thermal cycling, and cyclic bending.
• Soldering Technologies Enabling Medical Device Packaging in the 3D Era. This paper will review the various forms of soldering for medical electronics and other types of medical devices. It examines how soldering technology is evolving to meet the challenges of smaller devices, which are more sensitive to manufacturing processes. Flux and similar materials that enable new assembly processes in the era of 2.5D and 3D technology will also be discussed.
Sandy-Smith serves as a technical liaison between Indium Corporation's customers and internal departments, such as research and development and production, to ensure the best quality and selection of products. She earned two degrees from the international engineering program at the University of Rhode Island: one in chemical engineering with a focus on materials, the other in German language.
Showing posts with label Low Silver Alloys. Show all posts
Showing posts with label Low Silver Alloys. Show all posts
Friday, May 10, 2013
Thursday, September 13, 2012
Comparison of SAC105 and SAC305 Solders
Many BGA and CSP component suppliers have begun shipment of components with a variety of “second generation” Pb-free solder ball alloys. Much of the motivation for the alloy changes has been to improve mechanical shock resistance. Several publications have established the improved performance of such 2nd
level BGA/CSP sphere alloys; however, much less has been published regarding the thermal fatigue resistance of components with these new Pb-free ball alloys. As these components and alloys become mainstream, their use in situations where thermal fatigue resistance is critical to product life will become an important consideration. Therefore, an understanding of thermal fatigue performance for new alloys is
necessary for OEM/ EMS/ ODM companies to make design and procurement decisions, and for component suppliers to ensure the reliability of their products under a range of field use conditions.
In this study, the thermal fatigue performance under accelerated test conditions is compared for three common BGA ball alloys: SAC105, Sn-3.5Ag, and SAC305 as a control. Accelerated thermal cycle (ATC) testing was performed using 676 PBGA components with 1.0 mm pitch and electrolytic Ni/Au finished component pads. These components were assembled to high-temperature rated Cu-OSP coated printed circuit boards using SAC 305 solder paste, which represents one of the most common assembly practices in industry today. ATC testing was performed using the IPC-9701A TC1 condition of 0/100°C with 10-minute dwells (nominal); 3 different failure criteria were used in constructing the Weibull failure curves. The data indicate that SAC105 has the lowest thermal fatigue resistance among the alloys tested, with Sn-3.5Ag and SAC
305 having similar and superior performance. The impact of failure criterion on the Weibull curves is also presented. The implications of these findings and areas for further study are discussed.
Authored By:
Gregory Henshall, Hewlett-Packard Co.
Jasbir Bath, Bath Technical Consultancy
Sundar Sethuraman, Jabil
David Geiger, Flextronics International
Ahmer Syed, Amkor
M.J. Lee, Xilinx
Keith Newman and Livia Hu, Sun Microsystems
Dong Hyun Kim and Weidong Xie, Cisco Systems
Wade Eagar and Jack Waldvogel, Motorola
http://www.ipcoutlook.org/pdf/comparison_thermal_fatigue_ipc.pdf
Monday, July 16, 2012
LOW SILVER SOLDER ALLOY AND SOLDER PASTE COMPOSITION
A low silver solder alloy of the present invention comprises 0.05-2.0% by mass of silver; 1.0% by mass or less of copper; 3.0% by mass or less of antimony; 2.0% by mass or less of bismuth; 4.0% by mass or less of indium; 0.2% by mass or less of nickel; 0.1% by mass or less of germanium; 0.5% by mass or less of cobalt (provided that none of the copper, the antimony, the bismuth, the indium, the nickel, the germanium, and the cobalt is 0% by mass); and the residue is tin. According to the present invention, the long-term reliable low silver solder alloy is provided, wherein the low silver solder alloy permits the cost reduction by decreasing the Ag content, and has the excellent stretch, melting point, and strength, and also has the high fatigue resistance (thermal fatigue resistance).
| Page bookmark | US2012175020 (A1) - LOW SILVER SOLDER ALLOY AND SOLDER PASTE COMPOSITION | ||||
|---|---|---|---|---|---|
| Inventor(s): | IMAMURA YOJI [JP]; IKEDA KAZUKI [JP]; PIAO JIN YU [JP]; TAKEMOTO TADASHI [JP] + | ||||
| Applicant(s): | HARIMA CHEMICALS INC [JP] + | ||||
| Classification: |
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| Application number: | US201113376563 20110512 | ||||
| Priority number(s): | JP20100242916 20101029; WO2011JP60983 20110512 | ||||
| Also published as: |
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Friday, June 22, 2012
Microstructure, mechanical, and thermal properties of the Sn-1Ag-0.5Cu solder alloy bearing Fe for electronics applications
Microstructure, mechanical, and thermal properties of the Sn-1Ag-0.5Cu solder alloy bearing Fe for electronics applications: Author(s): Shnawah, D.A.-A. , Said, S.B.M. , Sabri, M.F.M. , Badruddin, I.A. , Che, F.X.
Publication year: 2012
Journal / Book title: Materials Science and Engineering A
This work investigates the effect of Fe addition on the microstructural, mechanical, and thermal properties of the Sn–1Ag–0.5Cu (SAC105) solder alloy. The addition of Fe leads to the formation of large circular FeSn2 intermetallic compound (IMC) particles, which produce a weak interface with the β-Sn matrix. The addition of Fe also leads to the inclusion of Fe in the Ag3Sn and Cu6Sn5 IMC particles. Moreover, Fe-bearing solders have been shown to form large primary β-Sn grains. The weak interface between the large FeSn2 IMC particles and the β-Sn matrix together with the presence of the large primary β-Sn grains results in a significant reduction on the elastic modulus and yield strength of the Fe-bearing solders. Moreover, the improved plasticity of the large primary β-Sn grains causes the Fe-bearing solders to exhibit large total elongation. The addition of Fe also significantly reduces the effect of aging. After aging at 100 °C and 180 °C, it has been observed that the Fe-bearing solders significantly suppress the coarsening of the Ag3Sn IMC particles; consequently, they exhibit stable mechanical properties. This effect can be attributed to the inclusion of Fe in the Ag3Sn IMC particles. In addition, fracture surface analysis indicates that the addition of Fe to the SAC105 solder alloy does not affect the mode of fracture, and all tested solders exhibited large ductile-dimples on the fracture surface. Moreover, the addition of Fe did not produce any significant effect on the melting behavior. As a result, the use conditions of the Fe-bearing solders are consistent with the conditions for conventional Sn–Ag–Cu solder alloys.
Materials Science and Engineering: A
Volume 551, 15 August 2012, Pages 160–168
Cover image
Microstructure, mechanical, and thermal properties of the Sn–1Ag–0.5Cu solder alloy bearing Fe for electronics applications
Dhafer Abdul-Ameer Shnawaha, Corresponding author contact information, E-mail the corresponding author,
Suhana Binti Mohd Saidb,
Mohd Faizul Mohd Sabria,
Irfan Anjum Badruddina,
Fa Xing Chec
a Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
b Department of Electrical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
c Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore
Publication year: 2012
Journal / Book title: Materials Science and Engineering A
This work investigates the effect of Fe addition on the microstructural, mechanical, and thermal properties of the Sn–1Ag–0.5Cu (SAC105) solder alloy. The addition of Fe leads to the formation of large circular FeSn2 intermetallic compound (IMC) particles, which produce a weak interface with the β-Sn matrix. The addition of Fe also leads to the inclusion of Fe in the Ag3Sn and Cu6Sn5 IMC particles. Moreover, Fe-bearing solders have been shown to form large primary β-Sn grains. The weak interface between the large FeSn2 IMC particles and the β-Sn matrix together with the presence of the large primary β-Sn grains results in a significant reduction on the elastic modulus and yield strength of the Fe-bearing solders. Moreover, the improved plasticity of the large primary β-Sn grains causes the Fe-bearing solders to exhibit large total elongation. The addition of Fe also significantly reduces the effect of aging. After aging at 100 °C and 180 °C, it has been observed that the Fe-bearing solders significantly suppress the coarsening of the Ag3Sn IMC particles; consequently, they exhibit stable mechanical properties. This effect can be attributed to the inclusion of Fe in the Ag3Sn IMC particles. In addition, fracture surface analysis indicates that the addition of Fe to the SAC105 solder alloy does not affect the mode of fracture, and all tested solders exhibited large ductile-dimples on the fracture surface. Moreover, the addition of Fe did not produce any significant effect on the melting behavior. As a result, the use conditions of the Fe-bearing solders are consistent with the conditions for conventional Sn–Ag–Cu solder alloys.
Materials Science and Engineering: A
Volume 551, 15 August 2012, Pages 160–168
Cover image
Microstructure, mechanical, and thermal properties of the Sn–1Ag–0.5Cu solder alloy bearing Fe for electronics applications
Dhafer Abdul-Ameer Shnawaha, Corresponding author contact information, E-mail the corresponding author,
Suhana Binti Mohd Saidb,
Mohd Faizul Mohd Sabria,
Irfan Anjum Badruddina,
Fa Xing Chec
a Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
b Department of Electrical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
c Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore
A comparison of the creep behaviour of joint-scale SAC105 and SAC305 solder samples under shear conditions
Scopus: This study compares the creep behavior of joint-scale Sn1.0Ag0.5Cu (SAC105) and Sn3.0Ag0.5Cu (SAC305) solder samples under shear loading. The basis of the comparison is experimentally derived Anand viscoplastic constitutive models for the alloys. A series of monotonic constant shear stress and constant shear strain rate tests was conducted at temperatures of 20'C, 50'C, 75'C and 100'C for SAC105 in order to provide data to extract the constitutive model parameters. The predictions of the Anand model are compared graphically with the experimental data for SAC105 in order to illustrate goodness-of-fit. The Anand parameters are shown to capture the creep performance of the SAC105 solder under shear loading very well, with the experimental data being tightly bound to the Anand predictions. For comparison, model parameters for SAC305 are taken from previously published work at the authors' institution. In terms of practical usage, SAC105 is noted to be preferable for applications which may experience high strain rate stimuli (portable electronic devices) as the alloy undergoes plastic flow at lower stress levels than SAC305, minimizing the risk of interfacial failures. Conversely, SAC305 is superior for applications which feature thermo-mechanical fatigue (desktop computers, for example, or servers) as it accumulates less strain than SAC105
2012 13th International Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2012
2012, Article number 6191722
2012 13th International Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2012;Cascais;16 April 2012through18 April 2012;Code89825
A comparison of the creep behaviour of joint-scale SAC105 and SAC305 solder samples under shear conditions ( Conference Paper )
Burke, C. , Punch, J.
CTVR, Stokes Institute, University of Limerick, Ireland
2012 13th International Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2012
2012, Article number 6191722
2012 13th International Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2012;Cascais;16 April 2012through18 April 2012;Code89825
A comparison of the creep behaviour of joint-scale SAC105 and SAC305 solder samples under shear conditions ( Conference Paper )
Burke, C. , Punch, J.
CTVR, Stokes Institute, University of Limerick, Ireland
The bulk alloy microstructure and tensile properties of Sn-1Ag-0.5Cu-xAl lead-free solder alloys (x = 0, 1, 1.5 and 2 wt.%)
Scopus : The purpose of this paper is to investigate the effect of Al addition on the bulk alloy microstructure and tensile properties of the low Ag-content Sn-1Ag-0.5Cu (SAC105) solder alloy.
Design/methodology/approach - The Sn-1Ag-0.5Cu-ITx/ITAl (ITx/IT=0, 1, 1.5 and 2?wt.%) bulk solder specimens with flat dog-bone shape were used for tensile testing in this work. The specimens were prepared by melting purity ingots of Sn, Ag, Cu and Al in an induction furnace. Subsequently, the molten alloys were poured into pre-heated stainless steel molds, and the molds were naturally air-cooled to room temperature. Finally, the molds were disassembled, and the dog-bone samples were removed. The solder specimens were subjected to tensile testing on an INSTRON tester with loading rate 10UP-3/UP?sUP-1/UP. The microstructural analysis was carried out using scanning electron microscopy/Energy dispersive X-ray spectroscopy. Electron Backscatter Diffraction (EBSD) analysis was used to identify the IMC phases. To obtain the microstructure, the solder samples were prepared by dicing, molding, grinding and polishing processes. Findings - The addition of Al to the SAC105 solder alloy suppresses the formation of AgDN3/DNSn and CuDN6/DNSnDN5/DN IMC particles and leads to the formation of larger Al-rich and Al-Cu IMC particles and a large amount of fine Al-Ag IMC particles. The addition of Al also leads to refining of the primary -Sn grains. The addition of Al results in a significant increase on the elastic modulus and yield strength. On the other hand, the addition of Al drastically deteriorates the total elongation. Originality/value - The addition of Al to the low Ag-content SAC105 solder alloy has been discussed for the first time. This work provides a starting-point to study the effect of Al addition on the drop impact and thermal cycling reliability of the SAC105 alloy.
Microelectronics International
Volume 29, Issue 2, 2012, Pages 108-116
The bulk alloy microstructure and tensile properties of Sn-1Ag-0.5Cu-xAl lead-free solder alloys (x = 0, 1, 1.5 and 2 wt.%)
Shnawah, D.A.-A.a , Sabri, M.F.M.a, Badruddin, I.A.a, Che, F.X.b
a Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, Malaysia
b Institute of Microelectronics, A STAR (Agency for Science, Technology and Research), Singapore, Singapore
Design/methodology/approach - The Sn-1Ag-0.5Cu-ITx/ITAl (ITx/IT=0, 1, 1.5 and 2?wt.%) bulk solder specimens with flat dog-bone shape were used for tensile testing in this work. The specimens were prepared by melting purity ingots of Sn, Ag, Cu and Al in an induction furnace. Subsequently, the molten alloys were poured into pre-heated stainless steel molds, and the molds were naturally air-cooled to room temperature. Finally, the molds were disassembled, and the dog-bone samples were removed. The solder specimens were subjected to tensile testing on an INSTRON tester with loading rate 10UP-3/UP?sUP-1/UP. The microstructural analysis was carried out using scanning electron microscopy/Energy dispersive X-ray spectroscopy. Electron Backscatter Diffraction (EBSD) analysis was used to identify the IMC phases. To obtain the microstructure, the solder samples were prepared by dicing, molding, grinding and polishing processes. Findings - The addition of Al to the SAC105 solder alloy suppresses the formation of AgDN3/DNSn and CuDN6/DNSnDN5/DN IMC particles and leads to the formation of larger Al-rich and Al-Cu IMC particles and a large amount of fine Al-Ag IMC particles. The addition of Al also leads to refining of the primary -Sn grains. The addition of Al results in a significant increase on the elastic modulus and yield strength. On the other hand, the addition of Al drastically deteriorates the total elongation. Originality/value - The addition of Al to the low Ag-content SAC105 solder alloy has been discussed for the first time. This work provides a starting-point to study the effect of Al addition on the drop impact and thermal cycling reliability of the SAC105 alloy.
Microelectronics International
Volume 29, Issue 2, 2012, Pages 108-116
The bulk alloy microstructure and tensile properties of Sn-1Ag-0.5Cu-xAl lead-free solder alloys (x = 0, 1, 1.5 and 2 wt.%)
Shnawah, D.A.-A.a , Sabri, M.F.M.a, Badruddin, I.A.a, Che, F.X.b
a Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, Malaysia
b Institute of Microelectronics, A STAR (Agency for Science, Technology and Research), Singapore, Singapore
Effect of Ni on growing of intermetallic compound in interface of Sn2·5Ag0·7Cu0·1RE/Cu solder joint during aging
Scopus Aging treatment was implemented for the Sn25Ag07Cu0 1RExNi/Cu solder joint under varioustemperatures simulating the service environment. The growing behaviour of the intermetalliccompound at the soldering interface during aging was investigated. In the case of adding 01%Niaged solder joint, the maximum growth activation energies of (Cu,Ni)6Sn5 and Cu3Sn are 86.8 and 93.7 kJ mol21 respectively. The results reveal that the growth of intermetallic compound in thesoldering interface can be suppressed, and the solder joint can be strengthened by addingproper quantities of Ni in the solder.
Materials Science and Technology (United Kingdom)
Volume 28, Issue 6, 2012, Pages 760-765
Effect of Ni on growing of intermetallic compound in interface of Sn2·5Ag0·7Cu0·1RE/Cu solder joint during aging
Zhang, K.K.ab , Li, C.Y.a, Qiu, R.F.ab, Shi, H.X.ab, Wang, Y.L.ab
a School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471003, China
b Henan Key Laboratory of Science and Processing Technology of Nonferrous Metals, Henan University of Science and Technology, Luoyang 471003, China
Materials Science and Technology (United Kingdom)
Volume 28, Issue 6, 2012, Pages 760-765
Effect of Ni on growing of intermetallic compound in interface of Sn2·5Ag0·7Cu0·1RE/Cu solder joint during aging
Zhang, K.K.ab , Li, C.Y.a, Qiu, R.F.ab, Shi, H.X.ab, Wang, Y.L.ab
a School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471003, China
b Henan Key Laboratory of Science and Processing Technology of Nonferrous Metals, Henan University of Science and Technology, Luoyang 471003, China
Drop impact reliability of Sn-1.0Ag-0.5Cu BGA interconnects with different mounting methods
Scopus: The poor drop-shock resistance of near-eutectic Sn-Ag-Cu (SAC) solder interconnects drives the research and application low-Ag SAC solder alloys, especially for Sn-1.0Ag-0.5Cu (SAC105). In this work, by dynamic four-point bend testing, we investigate the drop impact reliability of SAC105 alloy ball grid array (BGA) interconnects with two different surface mounting methods: near-eutectic solder paste printing and flux dipping. The results indicate that the flux dipping method improves the interconnects failure strain by 44.7% over paste printing. Further mechanism studies show the fine interfacial intermetallic compounds (IMCs) at the printed circuit board side and a reduced Ag content inside solder bulk are the main beneficial factors overcoming other negative factors. The flux dipping SAC105 BGA solder joints possess fine Cu 6Sn 5 IMCs at the interface of solder/Cu pads, which increases the bonding strength between the solder/IMCs and the fracture resistance of the IMC grains themselves. Short soldering time of flux dipping joints above the solder alloy liquidus mitigates the growth of interfacial IMCs in size. In addition, a reduced Ag content in flux dipping joint bulk causes a low hardness and high compliance, thus increasing fracture resistance under higher-strain rate conditions.
Microelectronics Reliability
Volume 52, Issue 7, July 2012, Pages 1475-1482
Drop impact reliability of Sn-1.0Ag-0.5Cu BGA interconnects with different mounting methods
Wang, B.ab, Li, J.a, Gallagher, A.c, Wrezel, J.c, Towashirporn, P.c, Zhao, N.a
a School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China
b Motorola Mobility Technologies Co. Ltd., Tianjin 300457, China
c Motorola Inc., Libertyville, IL 60048, United States
Microelectronics Reliability
Volume 52, Issue 7, July 2012, Pages 1475-1482
Drop impact reliability of Sn-1.0Ag-0.5Cu BGA interconnects with different mounting methods
Wang, B.ab, Li, J.a, Gallagher, A.c, Wrezel, J.c, Towashirporn, P.c, Zhao, N.a
a School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China
b Motorola Mobility Technologies Co. Ltd., Tianjin 300457, China
c Motorola Inc., Libertyville, IL 60048, United States
Microstructures and property of SnAgCu/SnAgCuCe solder joints
Scopus: For SnAgCu/SnAgCuCe solder joints, the microstructures, mechanical property and thermal fatigue property are investigated respectively. Results indicate that the mechanical properties of SnAgCu solder joints are enhanced with the addition of Ce, and the tensile forces of SnAgCuCe solder joints are 12.7% higher than that of SnAgCu solder joints. With the addition of rare earth Ce, the microstructure of SnAgCu can be refined, and the size of intermetallic compound (IMC) particles (Cu 6Sn 5 and Ag 3Sn) can be reduced, which are the reasons for the mechanical properties enhancement of SnAgCu solder joints. The SEM inspection and analysis show that fracture of the SnAgCu/SnAgCuCe solder joints presents obviously toughness fracture mechanism. In addition, during thermal cyclic loading, it is found that the addition of rare earth Ce can enhance the fatigue life of SnAgCu solder joints. Based on finite element simulation, it is found that SnAgCuCe solder joints shows higher creep resistance than that SnAgCu solder joints.
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering
Volume 48, Issue 8, 20 April 2012, Pages 67-73
Microstructures and property of SnAgCu/SnAgCuCe solder joints
Zhang, L.ab , Han, J.a, Guo, Y.a, Lai, Z.b, Zhang, L.c
a School of Mechanical and Electrical Engineering, Jiangsu Normal University, Xuzhou 221116, China
b Provincial Key Laboratory of Advanced Welding Technology, Jiangsu University of Science and Technology, Zhenjiang 212003, China
c Lucas Milhaupt Brazing Materials(Suzhou) Co., Ltd., Suzhou 215122, China
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering
Volume 48, Issue 8, 20 April 2012, Pages 67-73
Microstructures and property of SnAgCu/SnAgCuCe solder joints
Zhang, L.ab , Han, J.a, Guo, Y.a, Lai, Z.b, Zhang, L.c
a School of Mechanical and Electrical Engineering, Jiangsu Normal University, Xuzhou 221116, China
b Provincial Key Laboratory of Advanced Welding Technology, Jiangsu University of Science and Technology, Zhenjiang 212003, China
c Lucas Milhaupt Brazing Materials(Suzhou) Co., Ltd., Suzhou 215122, China
Nanoindentation for measuring mechanical properties of Lanthanum-doped tin-silver-copper lead-free solders
Scopus: The elimination of lead from electronics due to its toxic nature and hazardous environmental effects is pushing the manufacturers towards the lead free solders for which Sn-Ag-Cu (SAC) alloys are considered as the best substitute. These alloys still have coarse microstructure with soft tin matrix and hard Intermetallic Compounds (IMCs). Lanthanum is added for refining the microstructure and improving the mechanical properties of SAC solders. Nanoindentation is a useful technique to evaluate the mechanical properties at very small length scale. In this study, CSM nanoindentation setup is used to determine the Young's modulus and hardness of SAC and Lanthanum doped SAC alloys. Loadings from 100 μN to 1000 μN with 100 μN steps were applied and different dwell times from 10 seconds to 60 seconds were used to avoid the creep effects. The loading rates applied were twice that of loading. Average values for both Young's modulus and hardness were determined against indentation depth. Nanoindentation causes the pile-up effects in the soft β-tin phase and eutectic Sn phase which are determined and incorporated in the results. The new results are in a better agreement with the previous studies.
IBSC 2012 - Proceedings of the 5th International Brazing and Soldering Conference
2012, Pages 221-227
5th International Brazing and Soldering Conference, IBSC 2012;Las Vegas, NV;22 April 2012through25 April 2012;Code90195
Nanoindentation for measuring mechanical properties of Lanthanum-doped tin-silver-copper lead-free solders ( Conference Paper )
Sadiq, M.abc , Cherkaoui, M.abc, Lecomte, J.-S.d
a George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801 Ferst Drive NW, Atlanta, GA 30332, United States
b University of Paul Verlaine, LEM3 UMR CNRS 7239, île du Saulcy, Metz 57070, France
c UMI 2958, Georgia Tech., CNRS Georgia Tech Lorraine, Metz 57070, France
d ENSAM-Arts et Métiers ParisTech, LEM3 UMR CNRS 7239, 4 rue Augustin Fresnel, Metz 57078, France
IBSC 2012 - Proceedings of the 5th International Brazing and Soldering Conference
2012, Pages 221-227
5th International Brazing and Soldering Conference, IBSC 2012;Las Vegas, NV;22 April 2012through25 April 2012;Code90195
Nanoindentation for measuring mechanical properties of Lanthanum-doped tin-silver-copper lead-free solders ( Conference Paper )
Sadiq, M.abc , Cherkaoui, M.abc, Lecomte, J.-S.d
a George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801 Ferst Drive NW, Atlanta, GA 30332, United States
b University of Paul Verlaine, LEM3 UMR CNRS 7239, île du Saulcy, Metz 57070, France
c UMI 2958, Georgia Tech., CNRS Georgia Tech Lorraine, Metz 57070, France
d ENSAM-Arts et Métiers ParisTech, LEM3 UMR CNRS 7239, 4 rue Augustin Fresnel, Metz 57078, France
Tamura's Solder Paste Slashes Silver Use, Offers Same Performance
Factiva: -Tamura Corp. (6768) has developed a solder paste for the electronics industry that contains less than one-third the normal amount of silver but retains the same performance as regular solder paste, including a similar temperature range for melting.
Because the new solder paste uses far less silver, the manufacturing costs are less sensitive to swings in the precious metal's price, meaning Tamura can supply the product at a set price over longer periods of time to customers.
Tamura has already begun shipping samples and plans to enter into volume production later this month, aiming for its use in attaching electronic components -- such as capacitors, microchips and resistors -- to the circuit boards of computers, cellular phones and other products.
Most of the solder pastes now used for this purpose are free of lead and instead use silver, tin and copper as their main components. But while these two latter metals cost only several hundred yen per kilogram, silver costs around 100,000 yen per kilogram, so fluctuations in the silver market can significantly impact solder paste prices.
Whereas typical solder paste has a 3% silver content, Tamura's new product contains at most 1%.
Reducing the silver this way normally boosts the melt temperature of the solder, requiring higher temperatures for soldering that can damage semiconductors and other components. But Tamura was able to solve this problem by developing an improved additive that contains no halogen compounds and yields a solder paste that melts in the range of 211-224 C, which is comparable to the 217-220 C range of regular solder paste.
The company targets annual sales of 600 million yen after three years for the new solder paste.
(The Nikkei Business Daily, June 14 edition)
Microstructure, mechanical, and thermal properties of the Sn-1Ag-0.5Cu solder alloy bearing Fe for electronics applications
Microstructure, mechanical, and thermal properties of the Sn-1Ag-0.5Cu solder alloy bearing Fe for electronics applications: Author(s): Shnawah, D.A.A. , Said, S.B.M. , Sabri, M.F.M. , Badruddin, I.A. , Che, F.X.
Publication year: 2012
Journal / Book title: Materials Science and Engineering A
This work investigates the effect of Fe addition on the microstructural, mechanical, and thermal properties of the Sn-1Ag-0.5Cu (SAC105) solder alloy. The addition of Fe leads to the formation of large circular FeSn 2 intermetallic compound (IMC) particles, which produce a weak interface with the β-Sn matrix. The addition of Fe also leads to the inclusion of Fe in the Ag 3Sn and Cu 6Sn 5 IMC particles. Moreover, Fe-bearing solders have been shown to form large primary β-Sn grains. The weak interface between the large FeSn 2 IMC particles and the β-Sn matrix together with the presence of the large primary β-Sn grains results in a significant reduction on the elastic modulus and yield strength of the Fe-bearing solders. Moreover, the improved plasticity of the large primary β-Sn grains causes the Fe-bearing solders to exhibit large total elongation. The addition of Fe also significantly reduces the effect of aging. After aging at 100°C and 180°C, it has been observed that the Fe-bearing solders significantly suppress the coarsening of the Ag 3Sn IMC particles; consequently, they exhibit stable mechanical properties. This effect can be attributed to the inclusion of Fe in the Ag 3Sn IMC particles. In addition, fracture surface analysis indicates that the addition of Fe to the SAC105 solder alloy does not affect the mode of fracture, and all tested solders exhibited large ductile-dimples on the fracture surface. Moreover, the addition of Fe did not produce any significant effect on the melting behavior. As a result, the use conditions of the Fe-bearing solders are consistent with the conditions for conventional Sn-Ag-Cu solder alloys.
Access all results for your search in Scopus
Publication year: 2012
Journal / Book title: Materials Science and Engineering A
This work investigates the effect of Fe addition on the microstructural, mechanical, and thermal properties of the Sn-1Ag-0.5Cu (SAC105) solder alloy. The addition of Fe leads to the formation of large circular FeSn 2 intermetallic compound (IMC) particles, which produce a weak interface with the β-Sn matrix. The addition of Fe also leads to the inclusion of Fe in the Ag 3Sn and Cu 6Sn 5 IMC particles. Moreover, Fe-bearing solders have been shown to form large primary β-Sn grains. The weak interface between the large FeSn 2 IMC particles and the β-Sn matrix together with the presence of the large primary β-Sn grains results in a significant reduction on the elastic modulus and yield strength of the Fe-bearing solders. Moreover, the improved plasticity of the large primary β-Sn grains causes the Fe-bearing solders to exhibit large total elongation. The addition of Fe also significantly reduces the effect of aging. After aging at 100°C and 180°C, it has been observed that the Fe-bearing solders significantly suppress the coarsening of the Ag 3Sn IMC particles; consequently, they exhibit stable mechanical properties. This effect can be attributed to the inclusion of Fe in the Ag 3Sn IMC particles. In addition, fracture surface analysis indicates that the addition of Fe to the SAC105 solder alloy does not affect the mode of fracture, and all tested solders exhibited large ductile-dimples on the fracture surface. Moreover, the addition of Fe did not produce any significant effect on the melting behavior. As a result, the use conditions of the Fe-bearing solders are consistent with the conditions for conventional Sn-Ag-Cu solder alloys.
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Thursday, May 24, 2012
Do we really need ternary additives for low-silver alloys?
LinkedIn: Do we really need ternary additives for low-silver alloys?
This 2009 SMTA conference paper appears to show that SAC105 and SAC0307 have surprisingly similar properties to SAC305 without any ternary additives. Comments?
circuitmart.com circuitmart.com
February 28, 2011
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Tim Jensen • The answer is "it depends." Sure, you can run SAC105 and 0307 successfully and many people are doing that today. However, there are trade-offs when switching to these alloys from SAC305. First of all, low Ag alloys have a higher melting point. In addition, the thermal cycling reliability is not as good as SAC305 (although low Ag alloys do have better drop test performance). The low Ag alloys have a relatively big plastic range (217-227 C) which will hurt the wetting and coalescence.
The addition of dopants to low Ag alloys can help with these issues while still giving the user the cost benefit of less Ag. Every dopant doesn't help will all of these so it is critical for one to determine what characteristics are critical for their application and find the alloy that best meets their needs. SAC105 or 0307 may be the right choice for your application but are probably not ideal for every application.
I have given a number of presentations on alternative alloys to SAC305. I would be happy to share some of that information with interested parties.
This 2009 SMTA conference paper appears to show that SAC105 and SAC0307 have surprisingly similar properties to SAC305 without any ternary additives. Comments?
circuitmart.com circuitmart.com
February 28, 2011
Like CommentUnfollow Flag More
Ajita Kumar Nayak likes this
1 comment
Follow Tim (Indium Corporation)
Tim Jensen • The answer is "it depends." Sure, you can run SAC105 and 0307 successfully and many people are doing that today. However, there are trade-offs when switching to these alloys from SAC305. First of all, low Ag alloys have a higher melting point. In addition, the thermal cycling reliability is not as good as SAC305 (although low Ag alloys do have better drop test performance). The low Ag alloys have a relatively big plastic range (217-227 C) which will hurt the wetting and coalescence.
The addition of dopants to low Ag alloys can help with these issues while still giving the user the cost benefit of less Ag. Every dopant doesn't help will all of these so it is critical for one to determine what characteristics are critical for their application and find the alloy that best meets their needs. SAC105 or 0307 may be the right choice for your application but are probably not ideal for every application.
I have given a number of presentations on alternative alloys to SAC305. I would be happy to share some of that information with interested parties.
Drop Test Performance of BGA Assembly Using SAC105Ti Solder Sphere
IPC: Drop Test Performance of BGA Assembly Using SAC105Ti Solder Sphere
Presentation by Ning-Chen Lee, Ph.D. of Indium Corporation.
This presentation was recorded live in San Diego, California during the Technical Conference at IPC APEX EXPO® on February 28, 2012
Total run time of presentation: 30 minutes, 7 seconds
Ning-Cheng Lee, Ph.D., is the Vice President of Technology with Indium Corporation of America. He has been with Indium since 1986. Prior to joining Indium, he was with Morton Chemical and SCM. His more than 20 years of experience includes the development of fluxes and solder pastes for SMT industries in addition to a very extensive background in the development of underfills and adhesives.
Dr. Lee is the author of "Reflow Soldering Processes and Troubleshooting: SMT, BGA, CSP, and Flip Chip Technologies" published by Newnes and co-author of "Electronics Manufacturing with Lead-Free, Halogen-Free, and Conductive-Adhesive Materials" published by McGraw-Hill. He is also the author of a number of book chapters for several lead-free soldering books. He received awards from SMT Magazine in 1991 and 1993; from SMTA for best proceedings papers of SMI or SMTA international conferences in 2001 and from IPC for Honorable Mention Paper – USA at IPC APEX EXPO in 2008. He was honored as a Member of Distinction from SMTA in 2002, with a Lead Free Co-Operation Award from Soldertec in 2003, with an Exceptional Technical Achievement Award from CPMT in 2006, as a Distinguished Lecturer from CPMT in 2007, as a Distinguished Author from SMTA in 2009 and with an Electronics Manufacturing Technology Award from CPMT in 2010.
He currently serves on the SMTA board of directors and has served on the board of governors for CPMT. Among other editorial responsibilities, he serves as a member of an editorial advisory board for Soldering and Surface Mount Technology, Global SMT & Packaging and as associate editor for IEEE Transactions on Electronics Packaging Manufacturing. He has numerous publications to his credit and frequently is invited to make presentations at seminars, give keynote speeches and teach short courses on those subjects at international conferences and symposiums worldwide.
He holds a B.S. in chemistry from National Taiwan University (1973) and earned his Ph.D. in polymer science from the University of Akron (1981).
Presentation by Ning-Chen Lee, Ph.D. of Indium Corporation.
This presentation was recorded live in San Diego, California during the Technical Conference at IPC APEX EXPO® on February 28, 2012
Total run time of presentation: 30 minutes, 7 seconds
Ning-Cheng Lee, Ph.D., is the Vice President of Technology with Indium Corporation of America. He has been with Indium since 1986. Prior to joining Indium, he was with Morton Chemical and SCM. His more than 20 years of experience includes the development of fluxes and solder pastes for SMT industries in addition to a very extensive background in the development of underfills and adhesives.
Dr. Lee is the author of "Reflow Soldering Processes and Troubleshooting: SMT, BGA, CSP, and Flip Chip Technologies" published by Newnes and co-author of "Electronics Manufacturing with Lead-Free, Halogen-Free, and Conductive-Adhesive Materials" published by McGraw-Hill. He is also the author of a number of book chapters for several lead-free soldering books. He received awards from SMT Magazine in 1991 and 1993; from SMTA for best proceedings papers of SMI or SMTA international conferences in 2001 and from IPC for Honorable Mention Paper – USA at IPC APEX EXPO in 2008. He was honored as a Member of Distinction from SMTA in 2002, with a Lead Free Co-Operation Award from Soldertec in 2003, with an Exceptional Technical Achievement Award from CPMT in 2006, as a Distinguished Lecturer from CPMT in 2007, as a Distinguished Author from SMTA in 2009 and with an Electronics Manufacturing Technology Award from CPMT in 2010.
He currently serves on the SMTA board of directors and has served on the board of governors for CPMT. Among other editorial responsibilities, he serves as a member of an editorial advisory board for Soldering and Surface Mount Technology, Global SMT & Packaging and as associate editor for IEEE Transactions on Electronics Packaging Manufacturing. He has numerous publications to his credit and frequently is invited to make presentations at seminars, give keynote speeches and teach short courses on those subjects at international conferences and symposiums worldwide.
He holds a B.S. in chemistry from National Taiwan University (1973) and earned his Ph.D. in polymer science from the University of Akron (1981).
Wednesday, May 16, 2012
Effects of Zn addition and aging treatment on tensile properties of Sn-Ag-Cu alloys
Scopus: The effects of adding small amounts of Zn and conducting an aging treatment at elevated temperatures on the microstructure and tensile properties of low-Ag Sn-Ag-Cu alloys were investigated. The addition of Zn to Sn-Ag-Cu alloys inhibited the growth of intermetallic compounds. As the amount of Zn increased, the flow stress increased both before and after the aging treatment. In particular, the Sn-1Ag-0.3Cu-1Zn alloy exhibited the highest flow stress among all the examined alloys. Although the flow stress of the Sn-3Ag-0.5Cu alloy was originally higher than that of the Sn-1Ag-0.1Cu-0.4Zn and Sn-1Ag-0.3Cu-0.7Zn alloys, the flow stress of these two alloys was higher after aging for 500 h at 398 K than that of the Sn-3Ag-0.5Cu alloy. The addition of small amounts of Zn in Sn-Ag-Cu alloys suppressed the decline in the flow stress after the aging treatment
Journal of Alloys and Compounds
Volume 527, 25 June 2012, Pages 226-232
Effects of Zn addition and aging treatment on tensile properties of Sn-Ag-Cu alloys
Hamada, N.a , Uesugi, T.b, Takigawa, Y.b, Higashi, K.b
a Ishikawa Metal Co., Ltd., Sakai 592-8352, Japan
b Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531, Japan
Journal of Alloys and Compounds
Volume 527, 25 June 2012, Pages 226-232
Effects of Zn addition and aging treatment on tensile properties of Sn-Ag-Cu alloys
Hamada, N.a , Uesugi, T.b, Takigawa, Y.b, Higashi, K.b
a Ishikawa Metal Co., Ltd., Sakai 592-8352, Japan
b Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531, Japan
Effect of Ni and Bi addition on growth rate of intermetallic compound of SnAgCu soldering
Scopus: The effects of Ni and Bi addition on the intermetallic compound (IMC) growth rate of low-Ag (<1%, mass fraction) Sn-Ag-Cu(LASAC) soldering were investigated by accelerated temperature aging. The thermal fatige resistance of LASAC solders with Ni and Bi addition was studied by comparing with SAC305 solder. The results show that thick Cu 3Sn layer forms after high temperature storage (HTS) aging between LASAC/Cu, LASAC-Bi/Cu and SAC305/Cu interfaces. While the IMC between LASAC-Ni/Cu is (Cu, Ni) 3Sn layer with a very thin thickness after aged. The IMC growth rate of SAC305 is 2.17x10 -5 μm 2/s. However, the IMC growth rate of LASAC solder is 3.810 -5 μm 2/s, which is faster than that of SAC305. The growth rate of IMC at LASAC/Cu interface decreases with Ni and Bi addition. Bi shows a better improvement for solder compared with Ni element. The IMC growth rate of LASAC-Bi is 1.92 x10 -5 μm 2/s, which is slower than the IMC growth rate of SAC305.
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals
Volume 22, Issue 2, February 2012, Pages 460-464
Effect of Ni and Bi addition on growth rate of intermetallic compound of SnAgCu soldering
Liu, Y., Sun, F.-L.
School of Materials Science and Engineering, Harbin University of Science and Technology, Harbin 150040, China
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals
Volume 22, Issue 2, February 2012, Pages 460-464
Effect of Ni and Bi addition on growth rate of intermetallic compound of SnAgCu soldering
Liu, Y., Sun, F.-L.
School of Materials Science and Engineering, Harbin University of Science and Technology, Harbin 150040, China
Novel Fe-containing Sn-1Ag-0.5Cu lead-free solder alloy with further enhanced elastic compliance and plastic energy dissipation ability for mobile products
Scopus : This work investigates the effects of small additions (0.1 and 0.3 wt.%) of Fe on the microstructure, mechanical, and thermal properties of the Sn-1Ag-0.5Cu (SAC105) solder alloy. The addition of Fe leads to the formation of large FeSn 2 intermetallic compound (IMC) particles located in the eutectic regions besides the small Ag 3Sn and Cu 6Sn 5 IMC particles. Fe-bearing solders have also been shown to form large primary β-Sn grains. The formation of large FeSn 2 IMC particles, together with the presence of large primary β-Sn grains have resulted in a significant reduction on the elastic modulus and yield strength. Moreover, the presence of large primary β-Sn grains causes the Fe-bearing solders to maintain the total elongation at the SAC105 level. This effect can increase the elastic compliance and plastic energy dissipation ability of the bulk solder, which play an important role in drop impact performance enhancement. The addition of Fe did not produce any significant effect on the melting behavior. As a result, the use conditions of the Fe-bearing solders are consistent with the conditions for conventional Sn-Ag-Cu solder alloys
Microelectronics Reliability
2012
Novel Fe-containing Sn-1Ag-0.5Cu lead-free solder alloy with further enhanced elastic compliance and plastic energy dissipation ability for mobile products ( Articles not published yet, but available online Article in press About articles in press (opens in a new window) )
Shnawah, D.A.-A.a , Said, S.B.M.b, Sabri, M.F.M.a, Badruddin, I.A.a, Che, F.X.c
a Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
b Department of Electrical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
c Institute of Microelectronics, ASTAR (Agency for Science, Technology and Research), 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore
Microelectronics Reliability
2012
Novel Fe-containing Sn-1Ag-0.5Cu lead-free solder alloy with further enhanced elastic compliance and plastic energy dissipation ability for mobile products ( Articles not published yet, but available online Article in press About articles in press (opens in a new window) )
Shnawah, D.A.-A.a , Said, S.B.M.b, Sabri, M.F.M.a, Badruddin, I.A.a, Che, F.X.c
a Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
b Department of Electrical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
c Institute of Microelectronics, ASTAR (Agency for Science, Technology and Research), 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore
LOW-SILVER-CONTENT SOLDER ALLOY AND SOLDER PASTE COMPOSITION
Espacenet This low-silver-content solder alloy comprises 0.05-2.0 mass% of silver, 1.0 mass% or less of copper, 3.0 mass% or less of antimony, 2.0 mass% or less of bismuth, 4.0 mass% or less of indium, 0.2 mass% or less of nickel, 0.1 mass% or less of germanium and 0.5 mass% or less of cobalt (wherein the content of each of the above-mentioned elements copper, antimony, bismuth, indium, nickel, germanium and cobalt is not 0 mass%), with the remainder being tin. According to the present invention, it becomes possible to provide a low-silver-content solder alloy which has a reduced Ag content and therefore can be produced at reduced cost, has excellent stretching properties, an excellent melting point, excellent strength and the like, and also has high fatigue resistance (cold thermal fatigue resistance) and long-lasting reliability.
WO2012056753 (A1) - LOW-SILVER-CONTENT SOLDER ALLOY AND SOLDER PASTE COMPOSITION
Inventor(s): IMAMURA YOJI [JP]; IKEDA KAZUKI [JP]; PIAO JINYU [JP]; TAKEMOTO TADASHI [JP] +
Applicant(s): HARIMA CHEMICALS INC [JP]; IMAMURA YOJI [JP]; IKEDA KAZUKI [JP]; PIAO JINYU [JP]; TAKEMOTO TADASHI [JP] +
Classification:
- international: B23K35/22; B23K35/26; C22C13/00; C22C13/02
- european:
Application number: WO2011JP60983 20110512
Priority number(s): JP20100242916 20101029
Also published as:
JP4787384 (B1)
WO2012056753 (A1) - LOW-SILVER-CONTENT SOLDER ALLOY AND SOLDER PASTE COMPOSITION
Inventor(s): IMAMURA YOJI [JP]; IKEDA KAZUKI [JP]; PIAO JINYU [JP]; TAKEMOTO TADASHI [JP] +
Applicant(s): HARIMA CHEMICALS INC [JP]; IMAMURA YOJI [JP]; IKEDA KAZUKI [JP]; PIAO JINYU [JP]; TAKEMOTO TADASHI [JP] +
Classification:
- international: B23K35/22; B23K35/26; C22C13/00; C22C13/02
- european:
Application number: WO2011JP60983 20110512
Priority number(s): JP20100242916 20101029
Also published as:
JP4787384 (B1)
Tuesday, May 15, 2012
The effects of dopants on the aging behavior of lead free solders
Scopus The microstructure, mechanical response, and failure behavior of lead free solder joints in electronic assemblies are constantly evolving when exposed to isothermal aging and/or thermal cycling environments. Over the past several years, we have demonstrated that the observed material behavior variations of Sn-Ag-Cu (SAC) lead free solders during room temperature aging (25 C) and elevated temperature aging (50, 75, 100, 125, and 150 C) were unexpectedly large and universally detrimental to reliability.
The measured stress-strain data demonstrated large reductions in stiffness, yield stress, ultimate strength, and strain to failure (up to 50%) during the first 6 months after reflow solidification. In addition, even more dramatic evolution was observed in the creep response of aged solders, where up to 100X increases were found in the steady state (secondary) creep strain rate (creep compliance) of lead free solders that were simply aged at room temperature. For elevated temperature aging at 125 C, the creep strain rate was observed to change even more dramatically (up to 10, 000X increase). There is much interest in the industry on establishing optimal SAC-based lead free solder alloys that minimize aging effects and thus enhance thermal cycling and elevated temperature reliability. During the past year, we have extended our previous studies to include several doped SAC alloys (SAC-X) where the standard SAC alloys have been modified with small percentages of one or two additional elements (X). Materials under consideration include SAC0307-X, Sn-.7Cu-X, SAC305-X, SAC3595-X and SAC3810-X. Using dopants (e.g. Bi, In, Ni, La, Mg, Mn, Ce, Co, Ti, etc.) has become widespread to enhance shock/drop reliability, and we have extended this approach to examine the ability of dopants reduce the effects of aging and extend thermal cycling reliability. In the current paper, we concentrate on showing results for SACX TM, which has the composition Sn-0.3Ag-0.7Cu-X with X = 0.1Bi. We have performed aging under 5 different conditions including room temperature (25 C), and four elevated temperatures (50, 75, 100 and 125). We have also extended the duration of aging considered in our experiments to up to 12 months of aging on selected alloys. Variations of the mechanical and creep properties (elastic modulus, yield stress, ultimate strength, creep compliance, etc.) have been observed. We have correlated the aging results for the doped SAX-X alloy with our prior data for the "standard" lead free alloys SACN05 (SAC105, SAC205, SAC305, SAC405).
The doped SAC-X alloy shows improvements (reductions) in the aging-induced degradation in stiffness, strength, and creep rate when compared to SAC105, even though it has lower silver content. In addition, the doped SAC-X alloy has been observed to reach a stabilized microstructure more rapidly when aged.
Mathematical models for the observed aging variations have been established so that the variation of the stress-strain and creep properties can be predicted as a function of aging time and aging temperature.
ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems, InterPACK 2011
Volume 2, 2011, Pages 733-748
ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems, InterPACK 2011;Portland, OR;6 July 2011through8 July 2011;Code89456
The effects of dopants on the aging behavior of lead free solders ( Conference Paper )
Cai, Z., Suhling, J.C. , Lall, P., Bozack, M.J.
Center for Advanced Vehicle Electronics, Auburn University, Auburn, AL 36849, United States
The measured stress-strain data demonstrated large reductions in stiffness, yield stress, ultimate strength, and strain to failure (up to 50%) during the first 6 months after reflow solidification. In addition, even more dramatic evolution was observed in the creep response of aged solders, where up to 100X increases were found in the steady state (secondary) creep strain rate (creep compliance) of lead free solders that were simply aged at room temperature. For elevated temperature aging at 125 C, the creep strain rate was observed to change even more dramatically (up to 10, 000X increase). There is much interest in the industry on establishing optimal SAC-based lead free solder alloys that minimize aging effects and thus enhance thermal cycling and elevated temperature reliability. During the past year, we have extended our previous studies to include several doped SAC alloys (SAC-X) where the standard SAC alloys have been modified with small percentages of one or two additional elements (X). Materials under consideration include SAC0307-X, Sn-.7Cu-X, SAC305-X, SAC3595-X and SAC3810-X. Using dopants (e.g. Bi, In, Ni, La, Mg, Mn, Ce, Co, Ti, etc.) has become widespread to enhance shock/drop reliability, and we have extended this approach to examine the ability of dopants reduce the effects of aging and extend thermal cycling reliability. In the current paper, we concentrate on showing results for SACX TM, which has the composition Sn-0.3Ag-0.7Cu-X with X = 0.1Bi. We have performed aging under 5 different conditions including room temperature (25 C), and four elevated temperatures (50, 75, 100 and 125). We have also extended the duration of aging considered in our experiments to up to 12 months of aging on selected alloys. Variations of the mechanical and creep properties (elastic modulus, yield stress, ultimate strength, creep compliance, etc.) have been observed. We have correlated the aging results for the doped SAX-X alloy with our prior data for the "standard" lead free alloys SACN05 (SAC105, SAC205, SAC305, SAC405).
The doped SAC-X alloy shows improvements (reductions) in the aging-induced degradation in stiffness, strength, and creep rate when compared to SAC105, even though it has lower silver content. In addition, the doped SAC-X alloy has been observed to reach a stabilized microstructure more rapidly when aged.
Mathematical models for the observed aging variations have been established so that the variation of the stress-strain and creep properties can be predicted as a function of aging time and aging temperature.
ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems, InterPACK 2011
Volume 2, 2011, Pages 733-748
ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems, InterPACK 2011;Portland, OR;6 July 2011through8 July 2011;Code89456
The effects of dopants on the aging behavior of lead free solders ( Conference Paper )
Cai, Z., Suhling, J.C. , Lall, P., Bozack, M.J.
Center for Advanced Vehicle Electronics, Auburn University, Auburn, AL 36849, United States
Low Ag alloys reliability studies in Malaysia
Factiva: "The purpose of this paper is to discuss the reliability of board level Sn-Ag-Cu (SAC) solder joints in terms of both thermal cycling and drop impact loading conditions, and further modification of the characteristics of low Ag-content SAC solder joints using minor alloying elements to withstand both thermal cycle and drop impact loads. Design/methodology/approach - The thermal cycling and drop impact reliability of different Ag-content SAC bulk solder will be discussed from the viewpoints of mechanical and micro-structural properties," investigators in Kuala Lumpur, Malaysia report.
"The best SAC composition for drop performance is not necessarily the best composition for optimum thermal cycling reliability. The content level of silver in SAC solder alloys can be an advantage or a disadvantage depending on the application, package and reliability requirements. The low Ag-content SAC alloys with different minor alloying elements such as Mn, Ce, Bi, Ni and Ti display good performance in terms of both thermal cycling and drop impact loading conditions. Originality/value - The paper details the mechanical and micro-structural properties requirements to design a robust bulk SAC solder joint," wrote D.A.A. Shnawah and colleagues, University of Malaya.
The researchers concluded: "These properties provide design and manufacturing engineers with the necessary information when deciding on a solder alloy for their specific application."
Shnawah and colleagues published their study in Microelectronics International (A review on effect of minor alloying elements on thermal cycling and drop impact reliability of low-Ag Sn-Ag-Cu solder joints. Microelectronics International, 2012;29(1):47-57).
For additional information, contact D.A.A. Shnawah, Univ Malaya, Dept. of Elect Engn, Kuala Lumpur, Malaysia.
"The best SAC composition for drop performance is not necessarily the best composition for optimum thermal cycling reliability. The content level of silver in SAC solder alloys can be an advantage or a disadvantage depending on the application, package and reliability requirements. The low Ag-content SAC alloys with different minor alloying elements such as Mn, Ce, Bi, Ni and Ti display good performance in terms of both thermal cycling and drop impact loading conditions. Originality/value - The paper details the mechanical and micro-structural properties requirements to design a robust bulk SAC solder joint," wrote D.A.A. Shnawah and colleagues, University of Malaya.
The researchers concluded: "These properties provide design and manufacturing engineers with the necessary information when deciding on a solder alloy for their specific application."
Shnawah and colleagues published their study in Microelectronics International (A review on effect of minor alloying elements on thermal cycling and drop impact reliability of low-Ag Sn-Ag-Cu solder joints. Microelectronics International, 2012;29(1):47-57).
For additional information, contact D.A.A. Shnawah, Univ Malaya, Dept. of Elect Engn, Kuala Lumpur, Malaysia.
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