Flux-Free Direct Chip Attachment of Solder-Bump Flip Chip by Ar + H2 Plasma Treatment
Authors: Hong, Soon-Min; Kang, Choon-Sik; Jung, Jae-Pil
Source: Journal of Electronic Materials, Volume 31, Number 10, 1 October 2002 , pp. 1104-1111(8)
Abstract:The flux-free flip-chip bonding process using plasma treatment was investigated. The effect of plasma-process parameters on Sn oxide-etching characteristics was evaluated by Auger depth-profile analysis. The die-shear test was performed to evaluate the adhesion strength of an Sn-37mass%Pb and Sn3.5mass%Ag solder-bump flip chip that was bonded after plasma treatment. The Ar + H2 plasma treatment reduced the thickness of the oxide layer on the Sn surface. The addition of H2 to the Ar plasma improved the oxide-etching characteristics. A low chamber pressure was more effective in oxide etching. The die-shear strength of the plasma-treated Sn-Pb and Sn-Ag solder flip chip was higher than that of the nontreated chip but lower than that of the fluxed chip. The difference in the die-shear strength between the plasma-treated specimen and the nontreated specimen increased with increasing bonding temperature. The plasma-treated flip chip fractured at the solder/top-surface metallurgy (TSM) interface at low bonding temperature, but at the solder/ under-bump metallurgy (UBM) interface at high bonding temperature.
Document Type: Miscellaneous
Publication date: October 1, 2002