A Bumping Process for 12" Wafers

A driving force to achieve increased speed and performance along with higher I/O count is the Flip Chip (FC) Technology which has therefore an high level of importance for a variety of applications. A breakthrough, however, will be the use of flip chip due to cost reduction. For this aim it is essential to use low cost bumping techniques. This paper shows a low cost wafer level bumping process based on a electroless Nickel/Gold Under Bump Metallization (UBM) for all Flip Chip Interconnection Technologies, like Flip Chip on Board or Flip Chip in Package which are used in industry today. The compatibility of Electroless Nickel Bumping to be implemented in wafer manufacturing with in the next millennium shows that this is a key technology, not only for wafer technologies in use today, especially for the wafer technologies of the next generation which includes 300 mm wafers and copper pads. A state of the art overview, and especially a Roadmap to future developments in semiconductor industry based on 300 mm wafers is shown.