Rapid Wafering of Wide Bandgap Substrates

OptiCOMP is developing a non-abrasive wafering technique that will reduce the cost of manufacturing wide bandgap semiconductor silicon carbide (SiC) and diamond substrates by a factor of two. These materials are very expensive. A 6” diameter SiC wafer costs a thousand dollars. Currently wafers are cut from boule using wire saws. These are heavy and bulky machines that cost up to a million dollars. Up to 50% of the crystal is lost to dust during wafering. About 500 micrometers worth of materials is lost to make a 500 micrometer thick wafer. It takes up to one week to cut 6” wafer due to the hardness of these materials. Also the diamond wire which is consumable is itself expensive and must be replaced often because it affects the uniformity of the cut. We drive a crack at a depth about 500 micrometers below the surface to separate a wafer from boule. This is fundamentally different from epitaxial lift-off which drives a shallow crack near the surface. The cleavage does not create subsurface damage. OptiCOMP´s technique yields savings in capital expenditures (CAPEX), materials, and time of wafering. This project will investigate ways to reduce the consumables and widen the area of cleavage. Approved for Public Release | 22-MDA-11215 (27 Jul 22)