US4721548A
Expired / Lapsed
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Semiconductor planarization process
Assignee: Intel Corp
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Filing: 1987-05-13
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Granted: 1988-01-26
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Expires: 2007-05-13
Abstract
Abstract Planarization process for planarizing glass layer which receives first layer metal. Spin-on-glass is cured in steam and then etched back using hydrofluoric and nitric acids diluted in acetic acids.
Inventors
- 👤 Seiichi Morimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:11
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H10P95/00; H10P95/06; H10P95/062; H10P95/064
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
47 words
In the fabrication of a semiconductor integrated circuit, a process for planarizing a glass layer comprising the steps of: covering said glass layer with a spin-on-glass layer; curing said spin-on-glass layer in an atmosphere of steam; wet etching said layers; whereby a planarized glass layer is formed.
Claim 2
Dependent Claim
47 words
In the fabrication of a semiconductor integrated circuit, a process for planarizing a glass layer comprising the steps of: covering said glass layer with a spin-on-glass layer; curing said spin-on-glass layer in an atmosphere of steam; wet etching said layers; whereby a planarized glass layer is formed.
Claim 3
Dependent Claim
22 words
The process defined by claim 1 wherein said curing occurs at a temperature of approximately 600 degrees C. to 650 degrees C.
Claim 4
Dependent Claim
18 words
The process defined by claim 2 wherein said wet etching comprises the use of hydrofluoric and nitric acids.
Claim 5
Dependent Claim
11 words
The process defined by claim 3 wherein said acids are diluted.
Claim 6
Dependent Claim
14 words
The process defined by claim 4 wherein said acids are diluted with acetic acid.
Claim 7
Dependent Claim
32 words
The process defined by claims 1 or 3 wherein said glass layer is heated to a sufficient temperature to cause glass reflow prior to covering said glass layer with said spin-on-glass layer.
Claim 8
Dependent Claim
79 words
In the fabrication of a semiconductor integrated circuit, a process for planarizing a glass layer which is formed over underlying polysilicon members comprising the steps of: covering said glass layer with a spin-on-glass layer; curing said spin-on-glass layer in an atmosphere of steam at a temperature or approximately 600 degrees C. to 650 degrees C.; wet etching said layers with an etchant which etches both said layers at approximately the same rate; whereby a planarized glass layer is formed.
Claim 9
Dependent Claim
79 words
In the fabrication of a semiconductor integrated circuit, a process for planarizing a glass layer which is formed over underlying polysilicon members comprising the steps of: covering said glass layer with a spin-on-glass layer; curing said spin-on-glass layer in an atmosphere of steam at a temperature or approximately 600 degrees C. to 650 degrees C.; wet etching said layers with an etchant which etches both said layers at approximately the same rate; whereby a planarized glass layer is formed.
Claim 10
Dependent Claim
15 words
The process defined by claim 7 wherein said wet etchant comprises hydrofluoric and nitric acids.
Claim 11
Dependent Claim
14 words
The process defined by claim 8 wherein said acids are diluted in acetic acid.
Claim 12
Dependent Claim
34 words
The process defined by claims 7 or 9 wherein prior to covering said glass layer with said spin-on-glass layer, said glass layer is subjected to an elevated temperature so as to cause glass reflow.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-01-25 | 1991-07-27 | 1992-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-25 | 1995-07-27 | 1996-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-25 | 1999-07-27 | 2000-01-26 | $7700.00 | Window Closed / Lapsed |