Patent ID: 8779433

Claim:
A semiconductor device comprising: a first transistor; a second transistor having a portion which overlaps with the first transistor; and an insulating film over a part of the first transistor, wherein the first transistor comprises: a first channel formation region; a first gate insulating layer provided over the first channel formation region; a first gate electrode provided over the first gate insulating layer so as to overlap with the first channel formation region; and a first source electrode and a first drain electrode electrically connected to the first channel formation region, wherein the second transistor comprises: a second channel formation region over the insulating film; a second source electrode and a second drain electrode electrically connected to the second channel formation region; a second gate electrode provided so as to overlap with the second channel formation region; and a second gate insulating layer provided between the second channel formation region and the second gate electrode, wherein the first gate electrode is surrounded by the insulating film and the insulating film does not cover a top surface of the first gate electrode, and wherein the second source electrode is formed of a material having etching selectivity with respect to the first gate electrode and the second source electrode is provided on and in contact with the top surface of the first gate electrode.