Patent ID: 7537978
Filing Date: 2009-05-26
Classification: H01L

Abstract:
1. A method of manufacturing a semiconductor device forming a MISFET, comprising: forming a cavity inside a semiconductor substrate; forming a hole in the semiconductor substrate, the hole being connected to the cavity; forming a back gate insulating film on surfaces of the semiconductor substrate which are exposed from the cavity and hole; forming a back gate electrode in the cavity and hole having surfaces covered with the back gate insulating film; forming a dummy gate in a region on the semiconductor substrate in which a gate electrode of the MISFET is to be formed; implanting impurities into portions of the semiconductor substrate which are not covered with the dummy gate, to form source and drain regions; forming an interlayer insulating film around the dummy gate; selectively removing the dummy gate, to form a gate groove having sidewalls made of the interlayer insulating film and exposing the semiconductor substrate and the back gate electrode; forming a front gate insulating film at a bottom surface of the gate groove; partially etching the front gate insulating film at the bottom surface of the gate groove, to form a contact hole connected to the back gate electrode; and forming a front gate electrode having a different work function from that of the back gate electrode in the gate groove and contact hole.