Patent ID: 7315076

Claim:
A display device comprising: a first silicon oxide film; a silicon nitride film stacked on the first silicon oxide film; a second silicon oxide film stacked on the silicon nitride film; and a contact hole extended through at least three layers which include the first silicon oxide film, the silicon nitride film and the second silicon oxide film, wherein the first silicon oxide film is a gate insulating film of a thin film transistor, the silicon nitride film and the second silicon oxide film are interlayer insulating films, and the contact hole is formed over each of source and drain regions of the thin film transistor, wherein a side wall of the contact hole is constituted by the first silicon oxide film, the silicon nitride film and the second silicon oxide film, and wherein letting d 2 and d 3 denote, respectively, a film thickness of the silicon nitride film and a film thickness of the second silicon oxide film, the silicon nitride film and the second silicon oxide film are stacked to satisfy the relationship d 2 <d 3 and the contact hole is formed to have a tapered shape free of constrictions.