Texas Instruments Incorporated
Selective wafer removal process for wafer bonding applications

Abstract:

A method includes attaching an optically transparent wafer to a first surface of an interposer wafer. The interposer wafer has a second surface opposite the first surface, and the second surface has a first channel therein. The method further includes attaching the interposer wafer to a first surface of a semiconductor wafer, and etching a second channel through the optically transparent wafer and through the interposer wafer. The method then includes applying wax into the second channel, and sawing through the optically transparent wafer and through at least a portion of the interposer wafer to form a third channel having a width that is wider than a width of the second channel. The wax is then removed to expose a portion of the first surface of the semiconductor wafer.