Tacky DotsTM technology for flip chip and BGA solder bumping

As the electronics market moves toward higher performance Integrated Circuits (ICs), each IC requires larger numbers of Inputs and Outputs (I/Os). This has resulted in a strong need in the marketplace for a low cost, high resolution method for placing controlled volumes of solder (or other metal alloys) on bond pads of ICs and area array semiconductor packages, such as Ball Grid Arrays (BGAs), and Chip Scale Packages (CSPs). To satisfy this need, DuPont has developed the concept of Tacky Dots^TM, which utilizes proprietary technology in photoimageable adhesives to form a pattern of tacky areas, which are subsequently populated with conductive particles and then transferred to ICs or packages. DuPont´s expertise and effort have been focused on developing a systems approach to the front end population process, while working closely with Texas Instruments who has developed technology to enable the effective transfer of the conductive particles. This paper contains details of the imaging and population technology as well as a discussion of the overall progress of this new wafer bumping process