The effects of printed circuit board electroless nickel immersion gold (ENIG) and organic solderability preservative (OSP) surface finishes on the electromigration reliability and shear strength of Sn-3.5Ag Pb-free solder bump were systematically investigated. In-situ annealing tests were performed in a scanning electron microscope chamber at 130, 150, and 170˚C in order to investigate the growth kinetics of intermetallic compound (IMC). Electromigration lifetime and failure modes were investigated at 150˚C and 1.5×105A/cm2, while ball shear tests and failure mode analysis were conducted under the high-speed conditions from 10 mm/s to 3000 mm/s. The activation energy of ENIG and OSP surface finishes during annealing were evaluated as 0.84 eV and 0.94 eV, respectively. The solder bumps with ENIG surface finish showed longer electromigration lifetime than OSP surface finish. Shear strengths between ENIG and OSP were similar, and the shear energies decreased with increasing shear speed. Failure analysis showed that electrical and mechanical reliabilities were very closely related to the interfacial IMC stabilities.

• 박영배( 안동대학교 신소재공학부 청정에너지 소재기술 연구센터) | 박영배
• 유세훈( 한국생산기술연구원 용접접합기술센터) | 유세훈
• 김재명( 스태츠칩팩코리아 기술연구소) | 김재명
• 이병록( 안동대학교 신소재공학부 청정에너지 소재기술 연구센터) | 이병록
• 김성혁(네패스 반도체연구소) | Kim, Sung-Hyuk