US5444018A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Metallization process for a semiconductor device
Assignee: Texas Instruments Inc
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Filing: 1993-10-13
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Granted: 1995-08-22
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Expires: 2013-10-13
Abstract
Abstract A contact for a semiconductor device has a via extending through a dielectric and collimated titanium in the via. Depositing titanium by collimation places sufficient metal into high aspect ratio contacts to make good electrical connection. The collimated titanium may be reacted in a nitrogen containing ambient to form a titanium silicide layer at the bottom of the contact and a titanium nitride layer over the titanium silicide layer. The titanium silicide layer provides good electrical contact to a device in a silicon semiconductor substrate and lowers contact resistance. Tungsten may be deposited over the colliminated titanium to form a conductor layer. The titanium nitride layer provides a sticking layer for the tungsten. The contact structure and the method are useful in high aspect ratio contacts present in VLSI multilevel interconnected devices such as dynamic random access memories.
Inventors
- 👤 Dennis J. Yost
- 👤 Thomas D. Bonifield
- 👤 Roc Blumenthal
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:51
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/0698
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
125 words
A method of fabricating a semiconductor device, comprising the steps of: providing a silicon substrate; forming a device region at the surface of said substrate; forming an insulating layer overlying said surface; forming an opening through said insulating layer to expose a portion of said device region; sputter depositing a film consisting only of titanium into the opening; annealing said titanium film in nitrogen to form silicide & nitride, and then chemical vapor depositing a film consisting essentially of tungsten into the opening, with silane reduction during said tungsten deposition, to prevent the tungsten from attacking the TiN; depositing a second tungsten film by hydrogen reduction to conformally fill the opening; and depositing a third tungsten film by hydrogen reduction to smooth the tungsten layers.
Claim 2
Independent Claim
125 words
A method of fabricating a semiconductor device, comprising the steps of: providing a silicon substrate; forming a device region at the surface of said substrate; forming an insulating layer overlying said surface; forming an opening through said insulating layer to expose a portion of said device region; sputter depositing a film consisting only of titanium into the opening; annealing said titanium film in nitrogen to form silicide & nitride, and then chemical vapor depositing a film consisting essentially of tungsten into the opening, with silane reduction during said tungsten deposition, to prevent the tungsten from attacking the TiN; depositing a second tungsten film by hydrogen reduction to conformally fill the opening; and depositing a third tungsten film by hydrogen reduction to smooth the tungsten layers.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein the titanium is directionally deposited into the opening.
Claim 4
Dependent Claim
17 words
The method of claim 2 wherein the titanium is directionally deposited into the opening by colliminated sputtering.
Claim 5
Independent Claim
110 words
A method of fabricating a semiconductor device, consisting of the following steps: providing a silicon substrate; forming device regions at the surface of said substrate; forming an insulating layer overlying said surface; forming an opening through said insulating layer to expose a portion of said device region; sputter depositing a film consisting only of titanium into the opening; annealing said titanium film in nitrogen to form silicide & nitride, and then chemical vapor depositing a film consisting essentially of tungsten into the opening, with a reducing atmosphere during said tungsten deposition; then depositing a second tungsten film by reduction to conformally fill the opening; and then smoothing the resulting surface.
Claim 6
Independent Claim
110 words
A method of fabricating a semiconductor device, consisting of the following steps: providing a silicon substrate; forming device regions at the surface of said substrate; forming an insulating layer overlying said surface; forming an opening through said insulating layer to expose a portion of said device region; sputter depositing a film consisting only of titanium into the opening; annealing said titanium film in nitrogen to form silicide & nitride, and then chemical vapor depositing a film consisting essentially of tungsten into the opening, with a reducing atmosphere during said tungsten deposition; then depositing a second tungsten film by reduction to conformally fill the opening; and then smoothing the resulting surface.
Claim 7
Dependent Claim
19 words
A method as in claim 4, wherein said opening has an aspect ratio on the order of about 2.5.
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) | 1998-08-21 | 1999-02-20 | 1999-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-08-21 | 2003-02-20 | 2003-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-08-21 | 2007-02-20 | 2007-08-22 | $7700.00 | Window Closed / Lapsed |