Patent US5576242A successfully refreshed from Google Patents.
US5576242A
Expired / Lapsed
US
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Method of forming self-aligned buried contact
Assignee: United Microelectronics Corp
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Filing: 1995-12-15
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Granted: 1996-11-19
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Expires: 2015-12-15
Abstract
Abstract Disclosed is a method of forming self-aligned buried contact implementing self-alignment technology into buried contact process to prevent failure of semiconductor elements due to disconnection of wiring which is caused by misalignment. This is done by forming a sidewall spacer in the recess on the buried contact region. The tolerance of misalignment is greatly increased because a polysilicon layer will contact with the buried contact region if the polysilicon layer could contact the sidewall spacer.
Inventors
- 👤 Ming-Hua Liu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:52
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/011
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
93 words
A process for forming self-aligned buried contact on a semiconductor substrate having a field oxide and a gate oxide grown thereon and a first polysilicon layer deposited thereon and a buried contact region formed thereon by etching, comprising the following steps of: depositing a second polysilicon layer thereon while forming a recess on the buried contact region; forming a sidewall spacer within said recess; depositing a tungsten silicate layer thereon; depositing and defining a second photoresist thereon; anisotropically etching said tungsten silicate layer and said second polysilicon layer; and removing said second photoresist.
Claim 2
Dependent Claim
93 words
A process for forming self-aligned buried contact on a semiconductor substrate having a field oxide and a gate oxide grown thereon and a first polysilicon layer deposited thereon and a buried contact region formed thereon by etching, comprising the following steps of: depositing a second polysilicon layer thereon while forming a recess on the buried contact region; forming a sidewall spacer within said recess; depositing a tungsten silicate layer thereon; depositing and defining a second photoresist thereon; anisotropically etching said tungsten silicate layer and said second polysilicon layer; and removing said second photoresist.
Claim 3
Dependent Claim
38 words
A process for forming self-aligned buried contact on a semiconductor substrate as claimed in claim 1, wherein impurities are implanted and driven in after depositing said second polysilicon layer to improve the conductivity of said second polysilicon layer.
Claim 4
Dependent Claim
34 words
A process for forming self-aligned buried contact on a semiconductor substrate as claimed in claim 1, wherein said step of forming the sidewall spacer includes depositing a silicon dioxide layer thereon and etching back.
Claim 5
Dependent Claim
30 words
A process for forming self-aligned buried contact on a semiconductor substrate as claimed in claim 3, wherein the thickness of said silicon dioxide layer is 1 KÅ to 1.5 KÅ.
Claim 6
Dependent Claim
34 words
A process for forming self-aligned buried contact on a semiconductor substrate as claimed in claim 1, wherein said step of forming the sidewall spacer includes depositing a silicon nitride layer thereon and etching back.
Claim 7
Dependent Claim
30 words
A process for forming self-aligned buried contact on a semiconductor substrate as claimed in claim 5, wherein the thickness of said silicon nitride layer is 1 KÅ to 1.5 KÅ.
Claim 8
Dependent Claim
80 words
A process for forming self-aligned buried contact on a semiconductor substrate having field oxide and gate oxide grown thereon and a first polysilicon layer deposited thereon and a buried contact region formed thereon by etching, comprising the following steps of: depositing a second polysilicon layer thereon while forming a recess on the buried contact region; forming a sidewall spacer within said recess; depositing and defining a second photoresist thereon; anisotropically etching said second polysilicon layer; and removing said second photoresist.
Claim 9
Dependent Claim
80 words
A process for forming self-aligned buried contact on a semiconductor substrate having field oxide and gate oxide grown thereon and a first polysilicon layer deposited thereon and a buried contact region formed thereon by etching, comprising the following steps of: depositing a second polysilicon layer thereon while forming a recess on the buried contact region; forming a sidewall spacer within said recess; depositing and defining a second photoresist thereon; anisotropically etching said second polysilicon layer; and removing said second photoresist.
Claim 10
Dependent Claim
34 words
A process for forming self-aligned buried contact on a semiconductor substrate as claimed in claim 7, wherein said step of forming the sidewall spacer includes depositing a silicon dioxide layer thereon and etching back.
Claim 11
Dependent Claim
30 words
A process for forming self-aligned buried contact on a semiconductor substrate as claimed in claim 8, wherein the thickness of said silicon dioxide layer is 1 KÅ to 1.5 KÅ.
Claim 12
Dependent Claim
34 words
A process for forming self-aligned buried contact on a semiconductor substrate as claimed in claim 7, wherein said step of forming the sidewall spacer includes depositing a silicon nitride layer thereon and etching back.
Claim 13
Dependent Claim
30 words
A process for forming self-aligned buried contact on a semiconductor substrate as claimed in claim 10, wherein the thickness of said silicon nitride layer is 1 KÅ to 1.5 KÅ.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-11-19 | 2000-05-20 | 2000-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-11-19 | 2004-05-20 | 2004-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-11-19 | 2008-05-20 | 2008-11-19 | $7700.00 | Window Closed / Lapsed |