Use of laser energy transparent stop layer to achieve minimal debris generation in laser scribing a multilayer patterned workpiece

Abstract

A solution to failure mechanisms caused by mechanical sawing of a mechanical semiconductor workpiece entails use of a laser beam to cut and remove the electrically conductive and low-k dielectric material layers from a dicing street before saw dicing to separate semiconductor devices. A laser beam forms a laser scribe region such as a channel in the electrically conductive and low-k dielectric material layers, the bottom of the channel ending on a laser energy transparent stop layer of silicon oxide lying below all of the electrically conductive and low-k dielectric material layers. The disclosed process entails selection of laser parameters such as wavelength, pulse width, and fluence that cooperate to leave the silicon oxide layer stop layer completely or nearly undamaged. A mechanical saw cuts the silicon oxide layer and all other material layers below it, as well as the substrate, to separate the semiconductor devices.