Stencil design for solder paste printing

摘要

A stencil design for solder paste printing, or other metal stencil printing, is disclosed. A stencil for stencil printing of solder onto a semiconductor wafer for semiconductor wafer bumping includes a substrate. The substrate has a hole defined therein substantially shaped to correspond to and receptive to the semiconductor wafer. An interior edge of the substrate surrounds the hole, and has an upper lip under which the semiconductor wafer is positioned. The upper lip of the interior edge of the substrate surrounding the hole substantially prevents the solder from flowing onto sides and a bottom of the semiconductor wafer during stencil printing of the solder. The cross-profile shape of the upper lip may in one embodiment be rectangular, whereas in another embodiment be triangular.