Method of manufacturing semiconductor substrate

Abstract

Disclosed is a method of manufacturing a semiconductor substrate by bonding two silicon crystalline wafers, and particularly, to a method of manufacturing a semiconductor substrate capable of reduced electrical resistance at the bonding interface. In the disclosed method, the silicon wafers to be bonded have at least one surface mirror-polished. Then they are washed, thus forming a natural oxide film on the surface. Then they are soaked in a concentrated HF solution for enough time to remove the oxide film formed on the surface. After that, the silicon wafers are soaked in ultra pure water to replace the fluorine atoms terminated on the surface thereof by OH groups, followed by drying. The silicon wafers thus treated are closely contacted with each other in such a manner that the mirror-polished surfaces are opposed to each other. The silicon wafers are thus bonded to each other by the hydrogen bonding forces due to the OH groups, and then heat treated for reinforcing the bonding.