Sn-3.0Ag-0.5Cu와 Sn-0.75Cu(-Ni,Bi) 솔더볼 합금조성에 따른 Heterogeneous BGA 솔더 접합부 열사이클 특성|RISS 상세보기

다국어 초록 (Multilingual Abstract)

Sn-3.0Ag-0.5Cu (SAC305) is one of the most commonly used Pb-free solder composition nowadays. A minor alloying element addition can improve mechanical properties and thermal reliability of the solder joint. Minor amount of Bithmuth (Bi) or Nickel (Ni) addition can improve mechanical properties of solder by solid solution strengthening, or ensure the structural stability of the intermetalllic compounds. Also, low melting temperature solder with Bithmuth can reduce the cost of soldering process and keep components from deterioration. In this study, reliability of heterogeneous and homogeneous solder joint in the ball-grid-array (BGA) package solder joint were investigated.
Using Sn-3.0Ag-0.5Cu (SAC305) solder paste and two kinds of solder balls, we have investigated which combination of solder joint improves the thermo-mechanical reliability. SAC305 and SCN (Sn-0.75Cu-Ni,Bi) balls were used for homogeneous and hetrogeneous joints. Solder balls were attached in BGA package. To examine the solder joint reliability, thermal cycling test was conducted after reflow soldering. Shear strength measurement and cross-sectional analysis of the BGA package solder joints were carried out before and after 2000 cycles of the test.
The shear strength of homogeneous solder joint decreased to 68.2% and heterogeneous decreased to 43.5%. The crosssectional analysis using scanning electorn microscopy (SEM) and electorn back-scattered diffraction (EBSD) showed the (Ni,Cu)6Sn5 and Cu6Sn5 IMCs which were generated in the solder joint, and the crack propagated longer in the homogeneous solder joint of SAC305 after the thermal cycling test. IPFM showed the grain refinement effect of the SCN solder joint after thermal cycling. The minor addition of Bi had played a role as dislocation pinning site and became to equiaxied grain, so that the lifetime of heterogeneous SCN solder joint was superior than that of the SAC305.

번역하기

참고문헌 (Reference)

1 S. Mokler, "The application of Bi-based solders for low temperature reflow to reduce cost while improving SMT yields in client computing systems" 318-326, 2016

2 Hye Min Lee ; 김미송 ; 홍원식, "Solder Joint Degradation and Electrochemical Metallic Ion Migration Property of Solder Joints with Surface Finish" 41 (41): 265-274, 2023

3 강혜준 ; 백범규 ; 정재필, "Recent Low Temperature Solder of SnBi and Its Bonding Characteristics" 38 (38): 576-583, 2020

4 이종현 ; 유아미 ; 김정한 ; 김목순 ; 강남현, "Reaction properties and interfacial intermetallics for Sn-xAg-0.5 Cu solders as a function of Ag content" 14 : 649-654, 2008

5 G. Iyer, "Pb-free solder: SAC105 vs SAC305 drop-test reliability data comparison" 251-255, 2007

6 이혜민 ; 김미송 ; 김명인 ; 홍원식, "Optimization of FC-CSP and MLCC Soldering Process Using Type 7 Solder Paste" 40 (40): 165-174, 2022

7 J. Wu, "Mining EDS-EBSD Data to Study Microstructure of Solder Bump with Completely Unknown Intermetallics" 1-4, 2022

8 김명인 ; 홍원식 ; Kim Mi-Song, "Laser Soldering Process Optimization of MEMS Probe of Probe Card for Semiconductor Wafer Test" 40 (40): 271-277, 2022

9 E. Hodúlová, "Kinetics of intermetallic phase formation at the interface of Sn-Ag-Cu-X (X= Bi, In) solders with Cu substrate" 509 (509): 7052-7059, 2011

10 Y. W. Lee, "Intermediate Low-Melting-Temperature Solder Thermal Cycling Enhancement Using Bismuth and Indium Microalloying" 52 : 810-818, 2023