US4657628A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for patterning local interconnects
Assignee: Texas Instruments Inc
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Filing: 1986-03-07
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Granted: 1987-04-14
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Expires: 2006-03-07
Abstract
Abstract A local interconnect system for VLSI integrated circuits. After titanium is deposited for self-aligned silicidation of exposed moat and gate regions in a nitrogen atmosphere, a hardmask is deposited and patterned over the titanium. When a conductive titanium nitride layer is formed overall, it will already be patterned according to this hardmask.
Inventors
- 👤 Thomas C. Holloway
- 👤 Thomas E. Tang
- 👤 Che-Chia Wei
- 👤 Roger A. Haken
- 👤 David A. Bell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:11
CPC Classifications
H; H10; H10B; H10B10/00; H10B10/12; H10B10/125; H10B41/00; H10B41/40; H10B41/42; H10B41/43; H10B41/48; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6316; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/064; H10W20/066; H10W20/0698; Y; Y10; Y10S; Y10S438/00; Y10S438/911
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
131 words
A process for fabricating integrated circuits including local interconnect, comprising the steps of: (a) providing a partially fabricated integrated circuit structure including moat regions, said moat regions incorporating active devices therein; (b) depositing a thin layer of metal consisting predominantly of titanium overall; (c) depositing a relatively inert material over said titanium in locations defining local interconnect pathways and/or locations of contacts to moat; (d) reacting said partially fabricated structure in an atmosphere containing a high portion of nitrogen, whereby portions of said titanium metal over moat regions are predominantly converted to titanium silicide, and portions of said titanium metal over oxide regions are converted predominantly to titanium nitride; (e) etching away exposed portions of said titanium and of said titanium nitride, to define local interconnects in predetermined local interconnect locations.
Claim 2
Dependent Claim
131 words
A process for fabricating integrated circuits including local interconnect, comprising the steps of: (a) providing a partially fabricated integrated circuit structure including moat regions, said moat regions incorporating active devices therein; (b) depositing a thin layer of metal consisting predominantly of titanium overall; (c) depositing a relatively inert material over said titanium in locations defining local interconnect pathways and/or locations of contacts to moat; (d) reacting said partially fabricated structure in an atmosphere containing a high portion of nitrogen, whereby portions of said titanium metal over moat regions are predominantly converted to titanium silicide, and portions of said titanium metal over oxide regions are converted predominantly to titanium nitride; (e) etching away exposed portions of said titanium and of said titanium nitride, to define local interconnects in predetermined local interconnect locations.
Claim 3
Dependent Claim
21 words
The process of claim 1, wherein said step (c) of depositing a relatively inert material comprises plasma-assisted deposition of silicon oxides.
Claim 4
Dependent Claim
32 words
The process of claim 1, wherein said step (c) of depositing a relatively inert material comprises plasma-assisted deposition of silicon oxides to a thickness in the range between 1000 and 2500 Angstroms.
Claim 5
Dependent Claim
20 words
The process of claim 1, wherein said retching step (e) is performed entirely as an etch at approximately atmospheric pressure.
Claim 6
Dependent Claim
17 words
The process of claim 1, wherein said retching step (e) is performed entirely as a wet etch.
Claim 7
Dependent Claim
27 words
The process of claim 1, further comprising the additional step, subsequent to said reacting step (d), of (f) annealing said titanium silicide regions to lower their resistivity.
Claim 8
Dependent Claim
45 words
The process of claim 6, wherein said reacting step (d) is performed at a temperature in the range of 500 to 750 degrees C., and said subsequent annealing step (f) is performed at a higher temperature in the range of 700 to 875 degrees C.
Claim 9
Dependent Claim
17 words
The process of claim 6, wherein said reacting step (d) is performed as a transient heating step.
Claim 10
Dependent Claim
64 words
The process of claim 6. (g) wherein said inert masking material is removed after said heating step (d) and before said annealing step (f), (f) and wherein said annealing step (f) is performed in an atmosphere comprising nitrogen, whereby remaining metallic portions of said metallic layer which had been under said inert masking material during said reacting step (d) are predominantly converted to nitride.
Claim 11
Dependent Claim
19 words
The process of claim 1, wherein said titanium metal is applied to a thickness of less than 2000 Angstroms.
Claim 12
Dependent Claim
24 words
The process of claim 1, wherein said reacting step (d) is performed at a temperature in the range of 500 to 750 degrees Centigrade.
References Cited (Backward Citations)
US3387952A
Cited
US4593454A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-13 | 1990-10-13 | 1991-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-13 | 1994-10-13 | 1995-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-13 | 1998-10-13 | 1999-04-14 | $7700.00 | Window Closed / Lapsed |