US4997789A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aluminum contact etch mask and etchstop for tungsten etchback
Assignee: Texas Instruments Inc
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Filing: 1988-10-31
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Granted: 1991-03-05
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Expires: 2008-10-31
Abstract
Abstract A method for forming CVD tungsten contacts in a planarized semiconductor body. The method utilizes aluminum as an etch mask and etch stop to prevent etching of underlying layers during contact formation.
Inventors
- 👤 Stephen A. Keller
- 👤 Piper A. Spry
- 👤 Martha S. Adams
- 👤 Ralph G. Harper
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:33
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/062; H10P; H10P50/00; H10P50/71; H10W20/032; H10W20/056; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/945
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
93 words
A method for forming metal interconnects comprising the steps of: providing a planarized semiconductor body; depositing a barrier layer over said semiconductor body; depositing a metal layer over said barrier layer; patterning and etching said barrier and metal layers to partially form contact openings; removing said patterning material; further etching said contact openings using said metal layers as an etch mask; depositing a conformal layer of non-selective tungsten over said semiconductor body to fill said contact openings; and planarizing said tungsten surface by tungsten resist etch back, said metal layer providing an etchstop.
Claim 2
Independent Claim
93 words
A method for forming metal interconnects comprising the steps of: providing a planarized semiconductor body; depositing a barrier layer over said semiconductor body; depositing a metal layer over said barrier layer; patterning and etching said barrier and metal layers to partially form contact openings; removing said patterning material; further etching said contact openings using said metal layers as an etch mask; depositing a conformal layer of non-selective tungsten over said semiconductor body to fill said contact openings; and planarizing said tungsten surface by tungsten resist etch back, said metal layer providing an etchstop.
Claim 3
Dependent Claim
13 words
The method of claim 1, wherein said barrier layer comprises a Titanium-Tungsten alloy.
Claim 4
Dependent Claim
22 words
The method of claim 1, wherein said metal layer comprises a metal chosen from the group consisting of copper, aluminum and silicon.
Claim 5
Dependent Claim
20 words
The method of claim 1, further including the step of depositing a TiW layer before deposition of said tungsten layer.
Claim 6
Dependent Claim
25 words
The method of claim 1, further including the step of depositing additional aluminum on said previously deposited aluminum to form a conventional contact metalization layer.
Claim 7
Independent Claim
62 words
A method for forming metal interconnects in a semiconductor body, comprising the steps of: forming a planarized oxide layer over said semiconductor body; forming a barrier layer over said planarized oxide layer; forming an aluminum layer over said barrier layer; and forming CVD tungsten contacts in said layers between the surface of said oxide layer and the surface of said semiconductor body.
Claim 8
Independent Claim
62 words
A method for forming metal interconnects in a semiconductor body, comprising the steps of: forming a planarized oxide layer over said semiconductor body; forming a barrier layer over said planarized oxide layer; forming an aluminum layer over said barrier layer; and forming CVD tungsten contacts in said layers between the surface of said oxide layer and the surface of said semiconductor body.
Claim 9
Independent Claim
97 words
A method of forming interconnects in a semiconductor integrated circuit, comprising the steps of: forming a layer of a first metal over an insulator; forming an opening extending through said layer of first metal and said insulator; forming a layer of a second metal over said layer of first metal and filling said opening, said second metal selected from the group consisting of tungsten and tungsten alloys; and removing a portion of said layer of second metal outside of said opening by a process selective for removal of said second metal with respect to said first metal.
Claim 10
Independent Claim
97 words
A method of forming interconnects in a semiconductor integrated circuit, comprising the steps of: forming a layer of a first metal over an insulator; forming an opening extending through said layer of first metal and said insulator; forming a layer of a second metal over said layer of first metal and filling said opening, said second metal selected from the group consisting of tungsten and tungsten alloys; and removing a portion of said layer of second metal outside of said opening by a process selective for removal of said second metal with respect to said first metal.
Claim 11
Dependent Claim
20 words
The method of claim 7, wherein: said first metal is selected from the group consisting of aluminum and aluminum alloys.
Claim 12
Dependent Claim
59 words
The method of claim 8, wherein: said layer of first metal is on a first layer of titanium:tungsten and said first layer of titanium:tungsten is on said insulator; said layer of second metal is on a second layer of titanium:tungsten and said second layer of titanium:tungsten is on said layer of first metal; and said insulator is silicon dioxide.
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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) | 1994-03-04 | 1994-09-03 | 1995-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-04 | 1998-09-03 | 1999-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-04 | 2002-09-03 | 2003-03-05 | $7700.00 | Window Closed / Lapsed |