Patent US4539744A successfully refreshed from Google Patents.
US4539744A
Expired / Lapsed
US
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Semiconductor planarization process and structures made thereby
Assignee: National Semiconductor Corp
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Filing: 1984-02-03
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Granted: 1985-09-10
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Expires: 2004-02-03
Abstract
Abstract A silicon substrate having a silicon dioxide bird's head is provided. A thermal oxide layer is grown on the exposed silicon surface. A layer, e.g., 4000 A°, of phosphogermanosilicate glass is deposited on the thermal oxide and on the silicon dioxide bird's head. The structure is heated to 950° C., causing a reflow of the glass which results in a planar surface. The thermal oxide and the phosphogermanosilicate glass are then wet etched at the same rate with a solution of hydrofluoric acid, ammonium fluoride, and deionized water. The wet etch is terminated when the exposed silicon surface is reached, resulting in a smooth surface as defined by the planar reflow surface. Other embodiments are disclosed.
Inventors
- 👤 Greg Burton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:13
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H10P95/00; H10P95/06; H10W10/10; H10W10/13; H10P14/00; H10P14/60; H10P14/69; H10P14/692; H10P14/6921; H10P14/6922; H10P14/6923
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
134 words
A method of making a semiconductor structure, comprising the steps of: (a) providing a semiconductor substrate having at least one substantially planar surface, said substrate comprising silicon, (b) forming an electrically insulating pattern adjacent said surface, said insulating pattern comprising silicon dioxide and including at least one portion thereof which extends outward beyond and away from said remaining planar surface, (c) depositing a film of electrically insulating material over said surface and said portions, said material comprising germanosilicate glass, (d) planarizing said film of step (c), (e) wet etching said film of step (c) and said electrically insulating pattern of step (b) at substantially the same rate, and (f) terminating the etching step when a predetermined thickness of said film of step (c) and said electrically insulating pattern of step (b) have been etched.
Claim 2
Independent Claim
134 words
A method of making a semiconductor structure, comprising the steps of: (a) providing a semiconductor substrate having at least one substantially planar surface, said substrate comprising silicon, (b) forming an electrically insulating pattern adjacent said surface, said insulating pattern comprising silicon dioxide and including at least one portion thereof which extends outward beyond and away from said remaining planar surface, (c) depositing a film of electrically insulating material over said surface and said portions, said material comprising germanosilicate glass, (d) planarizing said film of step (c), (e) wet etching said film of step (c) and said electrically insulating pattern of step (b) at substantially the same rate, and (f) terminating the etching step when a predetermined thickness of said film of step (c) and said electrically insulating pattern of step (b) have been etched.
Claim 3
Dependent Claim
18 words
A method in accordance with claim 1 in which step (b) comprises oxidizing said surface of said substrate.
Claim 4
Dependent Claim
23 words
A method in accordance with claim 2 which comprises forming an oxide film on said remaining planar surface between steps b and c.
Claim 5
Dependent Claim
17 words
A method in accordance with claim 2 in which said glass includes P 2 O 5 .
Claim 6
Dependent Claim
51 words
A method in accordance with claim 4 in which said glass comprises SiO 2 in the range of from about 5% to about 80%, GeO 2 in the range of from about 10% to about 100% and P 2 O 5 in the range of from about 0% to about 10%.
Claim 7
Dependent Claim
25 words
A method in accordance with claim 2 in which step (d) comprises heating said glass to cause a reflow thereof and provide a planar surface.
Claim 8
Dependent Claim
24 words
A method in accordance with claim 6 which comprises heating said glass in the range of from about 850° C. to about 1100° C.
Claim 9
Dependent Claim
23 words
A method in accordance with claim 6 in which step (e) comprises wet etching with an etchant which does not react with silicon.
Claim 10
Dependent Claim
26 words
A method in accordance with claim 9 in which the step of wet etching utilizes an etchant which comprises hydrofluoric acid, ammonium fluoride, and deionized water.
Claim 11
Dependent Claim
49 words
A method in accordance with claim 10 in which said etchant comprises hydrofluoric acid in the range of from about 3% to about 30%, ammonium fluoride in the range of from about 10% to about 95%, and deionized water in the range of from about 0% to about 90%.
Claim 12
Dependent Claim
25 words
A method in accordance with claim 10 in which said etchant is maintained at a temperature of from about 15° C. to about 30° C.
Claim 13
Dependent Claim
24 words
A method in accordance with claim 4 in which said glass comprises SiO 2 in the range of from about 5% to about 80%.
Claim 14
Dependent Claim
23 words
A method in accordance with claim 4 in which said glass comprises GeO 2 in the range of from about 10% to 100%.
Claim 15
Dependent Claim
26 words
A method in accordance with claim 4 in which said glass comprises P 2 O 5 in the range of from about 0% to about 10%.
Claim 16
Dependent Claim
25 words
A method in accordance with claim 1 in which step (f) comprises terminating the etching step when said planar surface of the substrate is reached.
Claim 17
Independent Claim
133 words
A method of making a semiconductor structure, comprising the steps of: (a) providing a semiconductor substrate having at least one substantially planar surface, said substrate comprising silicon, (b) forming an electrically insulating pattern adjacent said surface, said insulating pattern comprising silicon dioxide and including at least one portion thereof which extends outward beyond and away from said remaining planar surface, (c) depositing a film of electrically insulating material over said surface and said portions, said material comprising germanosilicate glass, (d) planarizing said film of step (c), (e) wet etching said film of step (c) and said electrically insulating pattern of step (b) at predetermined different rates, and (f) terminating the etching step when a predetermined thickness of said film of step (c) and said electrically insulating pattern of step (b) have been etched.
Claim 18
Independent Claim
133 words
A method of making a semiconductor structure, comprising the steps of: (a) providing a semiconductor substrate having at least one substantially planar surface, said substrate comprising silicon, (b) forming an electrically insulating pattern adjacent said surface, said insulating pattern comprising silicon dioxide and including at least one portion thereof which extends outward beyond and away from said remaining planar surface, (c) depositing a film of electrically insulating material over said surface and said portions, said material comprising germanosilicate glass, (d) planarizing said film of step (c), (e) wet etching said film of step (c) and said electrically insulating pattern of step (b) at predetermined different rates, and (f) terminating the etching step when a predetermined thickness of said film of step (c) and said electrically insulating pattern of step (b) have been etched.
Claim 19
Dependent Claim
25 words
A method in accordance with claim 16 in which step (f) comprises terminating the etching step prior to reaching said planar surface of the substrate.
Claim 20
Dependent Claim
16 words
A method in accordance with claim 1 in which said one portion comprises a bird's head.
Claim 21
Independent Claim
129 words
A method of making a semiconductor structure, comprising the steps of: (a) providing a semiconductor substrate having at least one substantially planar surface, said substrate comprising silicon, (b) forming an electrically insulating pattern adjacent said surface, said insulating pattern comprising silicon dioxide and including at least one portion thereof which extends outward beyond and away from said remaining planar surface, (c) depositing a film of electrically insulating material over said surface, and said portions, said material comprising germanosilicate glass, (d) planarizing said film of step (c) (e) wet etching said film of step (c) and said electrically insulating pattern of step (b), and (f) terminating the etching step when a predetermined thickness of said film of step (c) and said electrically insulating pattern of step (b) have been etched.
Claim 22
Independent Claim
129 words
A method of making a semiconductor structure, comprising the steps of: (a) providing a semiconductor substrate having at least one substantially planar surface, said substrate comprising silicon, (b) forming an electrically insulating pattern adjacent said surface, said insulating pattern comprising silicon dioxide and including at least one portion thereof which extends outward beyond and away from said remaining planar surface, (c) depositing a film of electrically insulating material over said surface, and said portions, said material comprising germanosilicate glass, (d) planarizing said film of step (c) (e) wet etching said film of step (c) and said electrically insulating pattern of step (b), and (f) terminating the etching step when a predetermined thickness of said film of step (c) and said electrically insulating pattern of step (b) have been etched.
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) | 1988-09-09 | 1989-03-11 | 1989-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-09 | 1993-03-11 | 1993-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-09 | 1997-03-11 | 1997-09-10 | $7700.00 | Window Closed / Lapsed |