A shadow mask for depositing solder bumps includes additional dummy holes located adjacent holes corresponding to most of the perimeter chips of the wafer. The additional dummy provide more uniform plasma etching of contacts of the wafer, improve etching of contacts of perimeter chips, and lower contact...http://www.google.se/patents/US20030071329?utm_source=gb-gplus-sharePatent US20030071329 - Wafer integrated rigid support ring
