Combinatorially variable etching of stacks including two dissimilar materials for etch pit density inspection

摘要

Provided are methods of high productivity combinatorial (HPC) inspection of semiconductor substrates. A substrate includes two layers of dissimilar materials interfacing each other, such as a stack of a silicon bottom layer and an indium gallium arsenide top layer. The dissimilar materials have one or more of thermal, structural, and lattice mismatches. As a part of the inspection, the top layer is etched in a combinatorial manner. Specifically, the top layer is divided into multiple different site-isolated regions. One such region may be etched using different process conditions from another region. Specifically, etching temperature, etching duration and/or etchant composition may vary among the site-isolated regions. After combinatorial etching, each region is inspected to determine its etch-pit density (EPD) value. These values may be then analyzed to determine an overall EPD value for the substrate, which may involve discarding EPD values for over-etched and under-etched regions.

主权项

1. A method of high productivity combinatorial (HPC) inspection of a semiconductor substrate, the method comprising:
receiving the semiconductor substrate comprising a first layer and a second layer,
the first layer disposed over and directly interfacing the second layer,the first layer comprising a first material,the second layer comprising a second material,the first material and the second material having at least one of a thermal mismatch, a structural mismatch, or a lattice mismatch,the first layer comprising multiple site-isolated regions (SIRs) defined thereon; performing an etch process on a portion of the first layer in each SIR,
the etch process comprising exposing each of the SIRs to one of a plurality of etch process conditions,the etch process conditions being varied in a combinatorial manner between at least two of the SIRs; and inspecting each of the site-isolated regions to determine an etch-pit density (EPD) value.