비전도성 접착제를 이용한 COG 본딩용 Sn/Ag 범프에서 본딩 응력이 접속저항에 미치는 영향

Abstract

Chip-on-glass bonding using onconductive adhesive was accomplished with joining of the Sn/Ag bumps, and the average contact resistance of the Sn/Ag bump was measured with variation of the bonding stress. Average contact resistance of the Sn/Ag bump could be obtained from the slope of the curve for daisy chain resistance vs. number of Sn/Ag bumps. With increasing the bonding stress from 31.8 MPa to 69.8 MPa, the average contact resistance decreased from 30 mΩ/bump to 15.6 mΩ/bump. With further increasing the bonding stress above 69.8 MPa, however, the average contact resistance changed little within the range of 12.9~15.6 mΩ/bump. Among the factors affecting the contact resistance with variation of the bonding stress, plastic deformation of the Sn/Ag bump had larger effect than the amount of the microvoids remaining at the contact interface between Sn/Ag bumps.