Browsing by Author "Shih, Lin-Chi"

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Evaluation of Cu-bumps with lead-free solders for flip-chip package applications
(2009-12-01)
Lin, Kung-Liang
;
Chang, Edward-Yi
;
Shih, Lin-Chi
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Low cost electroplated Cu-bump with environmental friendly Sn solder was developed for flip-chip applications. The seed layer used was Ti/WN(x)/Ti/Cu where WN(x) was used as the Cu diffusion barrier and Ti was used to enhance the adhesion between bump and the chip pad. Thick negative photoresist (THB JSR-151N) with a high aspect ratio of 2.4 was used for electroplating of copper bump and Sn solder. The Sn solder cap was reflowed at 225 degrees for 6 min at N(2) atmosphere. No wetting phenomenon was observed for the Sn solder as evaluated by energy-dispersed spectroscopy (EDS). The Cu-bump with Ti/WN(x)/Ti/Cu seed layer not only have higher shear force than the Cu-bump with Ti/Cu seed layer but also has higher resistance to fatigue failure than the Au, SnCu, SnAg bumps. (C) 2009 Elsevier B.V. All rights reserved.