Investigation of high speed micro-bump formation through electrodeposition enhanced by megasonic agitation

Electroplating has been employed to produce metallic micro-bumps to meet the demand of high density flip chip interconnections for high-end electronic devices. Previous studies indicated that megasonic agitation is a promising approach to enable high speed electrodeposition and bumping which therefore can increase the productivity and reduce the cost of the process. This paper takes indium bumping as an example and reports further investigation of the electroplating bumping enhanced by megasonic agitation. Experimental results demonstrate that the bumping process could be accelerated to five times faster than the ordinary DC electroplating situation without any significant effect on the bump height uniformity.