Method of manufacturing a semiconductor device
AssigneeHynix Semiconductor Inc.
InventorMyung Gyu Choi
Life of this patent
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Abstract
The present invention relates to a method of manufacturing a semiconductor device. When a trench of a STI structure is formed, a portion of a pad nitride film on an active region is removed . Thus, formation of a moat around an upper corner portion of the trench of the STI structure is prevented. Also, the upper corner portion of the trench is rounded. Therefore, a parasitic effect, degradation in gate oxide integrity, an inverse narrow effect and a sub-threshold hump phenomenon can be prevented. Further, a breakdown phenomenon, a gate bridge phenomenon and difference in the coupling ratio between gate electrodes can be prevented.
Claims6
A method of manufacturing a semiconductor device, comprising steps in order of:
- (a) sequentially forming a pad oxide film, a pad nitride film and a screen oxide film on a semiconductor substrate in which an active region and a field region are defined;
- (b) removing the screen oxide film and the pad nitride film formed in the field region;
- (c) performing a wet etch process to remove a portion of the pad nitride film exposed at the boundary of the active region and the field region, in a lateral direction by a given width;
- (d) performing a dry etch process using the screen oxide film as an etch mask to remove portions of the pad oxide film and the semiconductor substrate formed in the field region, thus forming a trench;
- (e) removing the screen oxide film and simultaneously removing the exposed portion of the pad oxide film below said portion of the pad nitride film removed by the wet etch process;
- (f) performing an oxidation process to form a rounding oxide film in the exposed portion of the semiconductor substrate after simultaneously removing the screen oxide film and the exposed portion of the pad oxide film;
- (g) depositing a field oxide film of a thickness by which the trench is sufficiently buried and then polishing the field oxide film;
- and (h) removing the pad nitride film and the pad oxide film in the active region.
Dependencies are inferred from the claim text.