| 摘要 |
PURPOSE: To reduce the roughness of the chamfered parts of a GaAs wafer and to lessen breaks in the wafer by a method wherein before the GaAs wafer is subjected to double side polishing, the wafer is etched with a sulfuric acid etchant. CONSTITUTION: A GaAs wafer 1 is chamfered to form the circular formation of the wafer 1 and the orientation reference plane of the wafer 1; then, the wafer 1 is etched with a sulfuric acid etchant for making small the roughness of chamfered parts of the wafer 1. Then, a double side lapping aimed at the removal of a slice strain and an increase in the uniformity of the thickness of the wafer 1 is performed and moreover, the wafer 1 is again performed an etching with the sulfuric acid etchant for removing the strain caused by chamfering and a dirt. Then, the wafer 1 is held in a carrier 2, subjected to a double side polishing processing with upper and lower polishing clothes 7a and 7b, which are respectively mounted on upper and lower boards 3 and 4, subsequently, is subjected to a one side polishing processing. In such a way, the roughness of the chamfered parts of the wafer 1 is made small to obtain the GaAs wafer having few breaks therein. |
