Patent ID: 10629440

Abstract:
A composite wafer includes an oxide single crystal thin film of lithium tantalate or lithium niobate transferred onto the entire face of a support wafer and is free from cracking or peeling on a bonding interface between the support wafer and the oxide single crystal thin film. A method for manufacturing a composite wafer at least includes a step of forming an ion-implanted layer in an oxide single crystal wafer, a step of subjecting at least one of the ion-implanted surface of the oxide single crystal wafer and a surface of a support wafer to a surface activation treatment, a step of bonding the ion-implanted surface of the oxide single crystal wafer to the surface of the support wafer to form a laminate, a step of subjecting the laminate to a first heat treatment at a temperature not less than 90° C. and not causing cracking, a step of applying a mechanical impact to the ion-implanted layer, and a step of subjecting the support wafer having the transferred oxide single crystal thin film to a second heat treatment at 250° C. to 600° C. to yield a composite wafer.