Patent US5989971A successfully refreshed from Google Patents.
US5989971A
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Method for forming trenched polysilicon structure
Assignee: Promos Technologies Inc
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Filing: 1997-09-09
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Granted: 1999-11-23
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Expires: 2017-09-09
Abstract
Abstract A method for forming a trenched polysilicon structure can be applied to a semiconductor device. The method includes steps of: a) providing a polysilicon layer; b) forming a dielectric layer on the polysilicon layer; c) forming a rugged oxide layer on the dielectric layer; d) removing a portion of the dielectric layer which is not covered by the rugged oxide layer for exposing a corresponding portion of the polysilicon layer; e) forming a plurality of microtrenches by etching the corresponding portion of the polysilicon layer; and f) removing the rugged oxide layer and the dielectric layer to obtain the trenched polysilicon structure.
Inventors
- 👤 Tuby Tu
- 👤 Kuang-Chao Chen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:22
CPC Classifications
H; H10; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/692; H10D1/711; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/947; Y10S438/964
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
117 words
A method for forming a trenched polysilicon structure of a semiconductor device comprising steps of: a) providing a polysilicon layer; b) forming a dielectric layer on said polysilicon layer; c) depositing a rugged oxide layer on said dielectric layer by chemical vapor deposition (CVD) using tetra-ethyl-ortho-silicate (TEOS) as a gas source and introducing ozone into a reaction system; then d) removing a portion of said dielectric layer which is not covered by said rugged oxide layer for exposing a corresponding portion of said polysilicon layer; e) forming a plurality of microtrenches by etching said corresponding portion of said polysilicon layer; and f) removing said rugged oxide layer and said dielectric layer to obtain said trenched polysilicon structure.
Claim 2
Independent Claim
117 words
A method for forming a trenched polysilicon structure of a semiconductor device comprising steps of: a) providing a polysilicon layer; b) forming a dielectric layer on said polysilicon layer; c) depositing a rugged oxide layer on said dielectric layer by chemical vapor deposition (CVD) using tetra-ethyl-ortho-silicate (TEOS) as a gas source and introducing ozone into a reaction system; then d) removing a portion of said dielectric layer which is not covered by said rugged oxide layer for exposing a corresponding portion of said polysilicon layer; e) forming a plurality of microtrenches by etching said corresponding portion of said polysilicon layer; and f) removing said rugged oxide layer and said dielectric layer to obtain said trenched polysilicon structure.
Claim 3
Dependent Claim
22 words
A method according to claim 1 wherein in said step (b), a thickness of said dielectric layer is greater than 30 Å.
Claim 4
Dependent Claim
15 words
A method according to claim 2 wherein said dielectric layer is a silicon dioxide layer.
Claim 5
Dependent Claim
16 words
A method according to claim 3 wherein said silicon dioxide layer is formed by thermal oxidation.
Claim 6
Dependent Claim
18 words
A method according to claim 3 wherein said silicon dioxide layer is formed by chemical vapor deposition (CVD).
Claim 7
Dependent Claim
20 words
A method according to claim 5 wherein tetra-ethyl-ortho-silicate (TEOS) is used as a gas source for said chemical vapor deposition.
Claim 8
Dependent Claim
34 words
A method according to claim 1 wherein said dielectric layer is made of a dielectric selected from a group consisting of an updoped silicate glass, a doped silicate glass, a nitride, and an oxynitride.
Claim 9
Dependent Claim
25 words
A method according to claim 7 wherein said dielectric layer is formed by chemical vapor deposition (CVD) when made of doped silicate glass or nitride.
Claim 10
Dependent Claim
16 words
A method according to claim 1 wherein said rugged oxide layer is formed at 300˜600° C.
Claim 11
Dependent Claim
19 words
A method according to claim 9 wherein said rugged oxide layer is formed at a pressure of 300˜760 Torr.
Claim 12
Dependent Claim
24 words
A method according to claim 10 wherein said rugged oxide layer is formed by introducing greater than 4% of ozone in the reaction system.
Claim 13
Dependent Claim
24 words
A method according to claim 1 wherein in said step (d), said portion of said dielectric layer is removed by an etch back process.
Claim 14
Dependent Claim
16 words
A method according to claim 12 wherein said etch back process is an anisotropic etch process.
Claim 15
Dependent Claim
22 words
A method according to claim 1 wherein in said step (e), said plurality of microtrenches are formed by reactive ion etch (RIE).
Claim 16
Dependent Claim
20 words
A method according to claim 14 wherein a depth of each microtrench is ranged from 500 Å to 1 μm.
Claim 17
Dependent Claim
20 words
A method according to claim 14 wherein a selectivity ratio of said reactive ion etch (RIE) is greater than 20.
Claim 18
Dependent Claim
24 words
A method according to claim 1 wherein in said step (f), said rugged oxide layer and said dielectric layer are removed by wet etching.
Claim 19
Dependent Claim
24 words
A method according to claim 1 wherein in said step (f), said rugged oxide layer and said dielectric layer are removed by dry etching.
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