Patent ID: 7326642

Claim:
A method of fabricating a semiconductor device, comprising the steps of: (a) forming a base having a first surface and a second surface located on an opposite side to the first surface; the base including a low dielectric constant material film whose relative dielectric constant is lower than silicon; (b) forming a semiconductor element on a sacrificial substrate using an island-shaped semiconductor film; (c) forming an insulator film to cover the semiconductor element on the sacrificial substrate to bury the element in the insulator film; thereby forming a first semiconductor element layer; (d) joining the first semiconductor element layer and the first surface of the base together directly or by way of another layer; (e) eliminating the sacrificial substrate; (f) forming a first wiring layer on an opposite side of the first semiconductor element layer to the base directly or by way of another layer; and (g) forming an electrode on the second surface of the base the electrode forming a return path for a signal transmitted through the first wiring layer; wherein in the step (b), the island-shaped semiconductor film has a limited dimension that realizes a necessary characteristic of the semiconductor layer; and the base, the first semiconductor element layer, and the first wiring layer constitute a three-dimensional stacked structure.