Patent ID: 7335517

Claim:
A method of forming a multichip semiconductor device comprising: forming circuit components on a surface of a semiconductor substrate; forming a first interlayer insulating film over the surface of the semiconductor substrate; selectively etching the first interlayer insulating film and the semiconductor substrate to form a hole that passes through the first interlayer insulating film but not the semiconductor substrate; forming an insulating film on a sidewall and bottom of the hole to a thickness that does not fill up the hole; filling the hole covered with the insulating film with a metal to form a metal plug; forming a second interlayer insulating film on the first interlayer insulating film, the second interlayer insulating film covering the metal plug; processing a rear side of the semiconductor substrate to thereby expose the metal plug at the bottom of the hole; and stacking the semiconductor substrate on another semiconductor substrate such that the exposed metal plug at the bottom of the hole of the semiconductor substrate is electrically connected with another metal plug of the another semiconductor substrate, wherein the first interlayer insulating film has a first metal interconnection which is connected with one of the formed circuit components, the second interlayer insulating film has a second metal interconnection which passes through the second interlayer insulating film and which is connected with a portion of the metal plug and an area of the portion is smaller than a cross-sectional area of the metal plug.