US5387535A
Expired / Lapsed
US
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Method of fabricating semiconductor devices in CMOS technology with local interconnects
Assignee: TDK Micronas GmbH
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Filing: 1994-02-14
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Granted: 1995-02-07
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Expires: 2014-02-14
Abstract
Abstract A method of fabricating CMOS devices with local interconnects is disclosed which is performed in two stages. In the first stage, a SALICIDE process is carried out, and in the second stage, the local interconnects are formed.
Inventors
- 👤 Klaus Wilmsmeyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:02
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/064; H10W20/066; H10W20/0698
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
108 words
A method of fabricating CMOS devices with local interconnects during CMOS processing, characterized by the following steps: a) sputtering a layer (4) of heat-resistant metal; b) a first annealing step for forming a metal-silicide layer (10); c) selective etching of the unconverted metal layer (4); d) a second annealing step; e) sputtering another layer (41) of heat resistant metal and an overlying layer (51) of amorphous alpha silicon; f) a photolithographic process for patterning the silicon layer (51), followed by photoresist stripping, and another first annealing step for forming the metal-silicide layers (101); g) etching away the remainder of the metal layer (41); and h) another annealing step.
Claim 2
Independent Claim
108 words
A method of fabricating CMOS devices with local interconnects during CMOS processing, characterized by the following steps: a) sputtering a layer (4) of heat-resistant metal; b) a first annealing step for forming a metal-silicide layer (10); c) selective etching of the unconverted metal layer (4); d) a second annealing step; e) sputtering another layer (41) of heat resistant metal and an overlying layer (51) of amorphous alpha silicon; f) a photolithographic process for patterning the silicon layer (51), followed by photoresist stripping, and another first annealing step for forming the metal-silicide layers (101); g) etching away the remainder of the metal layer (41); and h) another annealing step.
Claim 3
Dependent Claim
19 words
A method as claimed in claim 1, characterized in that the heat-resistant metal is titanium, tungsten, molybdenum or tantalum.
Claim 4
Independent Claim
146 words
A method of fabricating CMOS devices with local interconnects during CMOS processing, said method comprising the steps of: (a) sputtering a layer (4) of a heat resistant metal on said devices; (b) annealing said devices to form a metal silicide layer (10) at portions of said layer of heat resistent metal in contact with silicon (c) etching the heat resistant metal; (d) sputtering another layer (41) of a heat resistant metal and an overlying layer (51) of amorphous alpha silicon on said devices; (e) patterning the overlying layer (51) of amorphous alpha silicon to define those regions in which said local interconnects are to be formed; (f) annealing said devices to form metal-silicide local interconnects (101) at those portions of said another layer of heat resistent metal which is in contact with the patterned amorphous alpha silicon; and (g) etching away the remaining heat resistent metal.
Claim 5
Independent Claim
146 words
A method of fabricating CMOS devices with local interconnects during CMOS processing, said method comprising the steps of: (a) sputtering a layer (4) of a heat resistant metal on said devices; (b) annealing said devices to form a metal silicide layer (10) at portions of said layer of heat resistent metal in contact with silicon (c) etching the heat resistant metal; (d) sputtering another layer (41) of a heat resistant metal and an overlying layer (51) of amorphous alpha silicon on said devices; (e) patterning the overlying layer (51) of amorphous alpha silicon to define those regions in which said local interconnects are to be formed; (f) annealing said devices to form metal-silicide local interconnects (101) at those portions of said another layer of heat resistent metal which is in contact with the patterned amorphous alpha silicon; and (g) etching away the remaining heat resistent metal.
Claim 6
Dependent Claim
46 words
The method of claim 3, further including another annealing step, which another annealing step occurs after step (c) in order to convert at least the metal-silicide formed at step (b) to a crystal structure having a lower resistivity than the metal-silicide originally formed at step (b).
Claim 7
Dependent Claim
39 words
The method of claim 3, further including another annealing step following step (g) to convert at least the metal-silicide formed at step (f) to a crystal structure having a lower resistivity than the metal-silicide originally formed at step (f).
Claim 8
Dependent Claim
22 words
The method of claim 5, wherein said heat resistent metal is selected from the group consisting of titanium, tungsten, molybdenum and tantalum.
Claim 9
Dependent Claim
19 words
The method of claim 6, wherein the metal-silicide originally formed at steps (b) and (f) is a C49 silicide.
Claim 10
Dependent Claim
17 words
The method of claim 7, wherein metal-silicide is converted to C54 silicide by said another annealing step.
Claim 11
Dependent Claim
22 words
The method of claim 8, wherein at least a portion of said metal-silicide local interconnects overlie field oxide formed in said devices.
Claim 12
Dependent Claim
23 words
The method of claim 9, wherein at least a portion of said metal-silicide local interconnects overlie polysilicon gate structures formed in said devices.
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) | 1998-02-06 | 1998-08-08 | 1999-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-06 | 2002-08-08 | 2003-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-06 | 2006-08-08 | 2007-02-07 | $7700.00 | Window Closed / Lapsed |