이방성 표면 거칠기를 가진 알루미늄 기판에서 초음파 출력과 본딩 방향이 와이어 본딩 강도에 미치는 영향

Abstract

Wire bonding is a key interconnection method in semiconductor packaging, where the bonding quality is affected by surface roughness, ultrasonic power, bonding force, and bonding orientation. In this study, aluminum (Al 6061) substrates were polished using three grit sizes (P220, P800, and P2000) and bonded under various ultrasonic power levels (1200, 1500, and 1700) in the horizontal and vertical directions. Shear tests were conducted to evaluate the bonding strength, and a scanning electron microscope was performed to observe the bonding surfaces. The results show that the strength is governed by the combined effects of surface conditions, orientation, and bonding parameters, instead of by any single factor. Excessive roughness or overpolishing reduces the strength compared with intermediate polishing, and the differences between horizontal and vertical bonding depend on the process conditions. These findings highlight that the wire-bonding quality depends on multiple interacting factors, thus underscoring the necessity for customized process adjustments to ensure reliable semiconductor packaging.