| Sn-3.0Ag-0.5Cu와 Sn-0.75Cu(-Ni,Bi) 솔더볼 합금조성에 따른 Heterogeneous BGA 솔더 접합부 열사이클 특성 |
배주영1 
, 김미송1
, 현소희1
, 이종현2, 문정탁3, 이영우3, 이슬기3, 김형태4, 백승관4, 홍원식1
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1한국전자기술연구원 융복합전자소재연구센터
2서울과학기술대학교 신소재공학과
3엠케이전자(주) 기술연구소 솔더개발팀
4아프로 알앤디(주) 신뢰성사업본부 |
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| Thermal Cycling Performance of Heterogeneous Solder Ball Joints with Sn-3.0Ag-0.5Cu and Sn-0.75Cu(-Ni,Bi) Solder Ball Composition for BGA Package |
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Joo Young Bae1
, Mi-Song Kim1
, So-Hee Hyun1
, Jong-Hyun Lee2, Jeong Tak Moon3, Young-Woo Lee3, Seul Gi Lee3, Hyeong-Tea Kim4, Seung-Kwan Baek4, Won Sik Hong1
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1Electronic Convergence Materials & Device Research Center, KETI, Seongnam, 13509, Korea
2Department of Materials Science & Engineering, Seoul National University of Science and Technology, Seoul, 01811, Korea
3Solder Development Team, R&D Center, MK Electron Co., Ltd. 316-2, Yongin, 17030, Korea
4Research Institute, APRO R&D, Seoul, 08377, Korea |
Correspondence:
Won Sik Hong,
Email: 03violett@keti.re.kr
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Received: 4 April 2024 • Revised: 16 April 2024 • Accepted: 18 April 2024 |
| Abstract |
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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 cross-sectional 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. |
| Key Words:
Ball grid array, Crack propagation, Pb-free solder, Thermal cycling test |
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