naa a22 4500 510804837 CHVBK 20180411083412.0 cr unu---uuuuu 180411e20130201xx s 000 0 eng 10.1007/s11664-012-2302-4 doi (NATIONALLICENCE)springer-10.1007/s11664-012-2302-4 Study of Intermetallic Growth and Kinetics in Fine-Pitch Lead-Free Solder Bumps for Next-Generation Flip-Chip Assemblies [Elektronische Daten] [Ye Tian, Justin Chow, Xi Liu, Yi Wu, Suresh Sitaraman] With continued advances in microelectronics, it is anticipated that next-generation microelectronic assemblies will require a reduction of the flip-chip solder bump pitch to 100μm or less from the current industrial practice of 130μm to 150μm. With this reduction in pitch size, and thus in bump height and diameter, the interaction between die pad metallurgy and substrate pad metallurgy becomes more critical due to the shorter diffusion path and greater stress. Existing literature has not addressed such metallurgical interaction in actual fine-pitch flip-chip assemblies. This work studies intermetallic growth and kinetics in fine-pitch lead-free solder bumps through thermal aging of flip-chip assemblies. Based on this study, it is seen that Ni from the die pad diffuses to the substrate pad region and Cu from the substrate pad diffuses to the die pad region, thus the resulting intermetallic compounds at the die and substrate pad regions are influenced by the other pad as well. Such cross-pad interaction is much stronger in fine-pitch solder bumps with smaller standoff height. It is seen that the die pad region contains Ni3P and (Cu,Ni)6Sn5 after thermal aging, while the substrate pad region contains Cu3Sn and (Cu,Ni)6Sn5. By digitally measuring the thickness of the interfacial phases, the kinetics parameters and the activation energy were calculated for the growth of (Cu,Ni)6Sn5 on the substrate side. The Cu diffusion coefficient through the intermetallic compound (IMC) layer was found to be 0.03370μm2/h, 0.1423μm2/h, and 0.4463μm2/h at 100°C, 125°C, and 150°C, respectively, and the apparent activation energy for the growth of compound layers was 67.89kJ/mol. TMS, 2012 Lead-free solders nationallicence intermetallic compounds nationallicence microstructure evolution nationallicence cross-reaction nationallicence Tian Ye School of Materials Science and Engineering, HuaZhong University of Science and Technology, 430074, Wuhan, China aut Chow Justin The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 30332, Atlanta, GA, USA aut Liu Xi The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 30332, Atlanta, GA, USA aut Wu Yi School of Materials Science and Engineering, HuaZhong University of Science and Technology, 430074, Wuhan, China aut Sitaraman Suresh The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 30332, Atlanta, GA, USA aut Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/2(2013-02-01), 230-239 0361-5235 42:2<230 2013 42 11664 https://doi.org/10.1007/s11664-012-2302-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11664-012-2302-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Tian Ye School of Materials Science and Engineering, HuaZhong University of Science and Technology, 430074, Wuhan, China aut NATIONALLICENCE 700 1- Chow Justin The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 30332, Atlanta, GA, USA aut NATIONALLICENCE 700 1- Liu Xi The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 30332, Atlanta, GA, USA aut NATIONALLICENCE 700 1- Wu Yi School of Materials Science and Engineering, HuaZhong University of Science and Technology, 430074, Wuhan, China aut NATIONALLICENCE 700 1- Sitaraman Suresh The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 30332, Atlanta, GA, USA aut NATIONALLICENCE 773 0- Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/2(2013-02-01), 230-239 0361-5235 42:2<230 2013 42 11664 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer