Bump formation for flip chip and CSP by solder paste printing

摘要

Area array packages (flip chip, CSP and BGA) require the formation of bumps for the board assembly, Since the established bumping methods need expensive equipment or are limited by the throughput, minimal pitch And yield the industry is currently searching for new and lower cost bumping approaches. In this paper the experi- Mental work of stencil printing to create solder bumps for flip chip and wafer level CSP (CSP-WL) is described in Detail. This paper is divided into two parts. In the first part of the paper a low cost wafer bumping process for flip chip Applications will be studied in particular.