Semiconductor device manufacture, employs SOI substrate with total insulation film separating elements of NMOS and PMOS devices

摘要

A multilayer substrate is prepared, with underlying- (1, 2) and semiconductor (3) layers. A first element insulation film (7a) is formed selectively, out of contact with the underlying layers, in a first main area of the semiconductor layer. An element is formed with conductive regions (20, 22) located only over the first insulation film (7a), on the first main area. At least one part of the underlying layers is removed, afterwards selectively forming a second insulation film, in contact with the first (7a), under the conductive regions (20, 22), in a second main area of the semiconductor layer.