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US 8,283,788 B2Granted
Method of fabricating semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorHongyong Zhang
Life of this patent
Estimating the term…
Abstract
Method of fabricating thin-film transistors in which contact with connecting electrodes becomes reliable. When contact holes are formed, the bottom insulating layer is subjected to a wet etching process, thus producing undercuttings inside the contact holes. In order to remove the undercuttings, a light etching process is carried out to widen the contact holes. Thus, tapering section are obtained, and the covering of connection wiring is improved.
Claims13
A semiconductor device comprising:
- a semiconductor substrate including at least a source region and a drain region;
- a gate electrode over the semiconductor substrate with a gate insulating film interposed therebetween;
- a first insulating film formed over the semiconductor substrate and the gate electrode;
- a second insulating film formed on the first insulating film;
- a contact hole formed in the first and second insulating films to reach at least one of the source region and the drain region;
- and
- an electrode electrically connected to at least one of the source region and the drain region through said contact hole,
- wherein an edge of said contact hole is rounded off at a top of said contact hole,
- wherein an inner side surface of the first insulating film in the contact hole at a bottom of the first insulating film has a first taper angle and an inner side surface of the second insulating film in the contact hole has a second taper angle, and the first taper angle is smaller than the second taper angle,
- wherein the electrode is in contact with the first insulating film and the second insulating film in the contact hole, and
- wherein the electrode fills the contact hole, and
- wherein the electrode does not cover the top of the contact hole, which is rounded off.
9 more elements
Dependencies are inferred from the claim text.