US4878994A
Expired / Lapsed
US
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Method for etching titanium nitride local interconnects
Assignee: Texas Instruments Inc
•
Filing: 1988-03-29
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Granted: 1989-11-07
•
Expires: 2008-03-29
Abstract
Abstract A process for the etching of titanium containing film which utilizes both in situ and remote plasmas, and a gas mixture for the plasmas which comprises a halogen gas at low pressure and moderate temperature to produce an etch which is both selective to selected materials, for example, titanium silicide etc., and anisotropic.
Inventors
- 👤 Rhett B. Jucha
- 👤 Cecil J. Davis
- 👤 Tom Tang
- 👤 Lee M. Loewenstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:15
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/53; C04B41/5338; C04B41/5346; C04B41/80; C04B41/91; C23; C23F; C23F4/00; H; H10; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267
Claims Analysis
Total Claims: 56
Claim 1
Independent Claim
63 words
A process for etching of a titanium containing film in a process chamber comprising the steps of: (a) generating at least free radicals from at least a halogen containing gas in remote plasma generator separated from the process chamber; (b) introducing said free radicals to said process chamber; and (c) generating an in situ plasma within the process chamber from said free radicals.
Claim 2
Dependent Claim
63 words
A process for etching of a titanium containing film in a process chamber comprising the steps of: (a) generating at least free radicals from at least a halogen containing gas in remote plasma generator separated from the process chamber; (b) introducing said free radicals to said process chamber; and (c) generating an in situ plasma within the process chamber from said free radicals.
Claim 3
Dependent Claim
14 words
The process as set forth in claim 1 wherein said film also includes titanium-oxygen.
Claim 4
Dependent Claim
15 words
The process as set forth in claim 1 wherein said film also includes titanium silicide.
Claim 5
Dependent Claim
30 words
The process as set forth in claim 1 wherein said gas selectively etches one taken from the group containing titanium-oxygen, titanium, titanium nitride or a combination thereof versus titanium silicide.
Claim 6
Dependent Claim
17 words
The process as set forth in claim 1 wherein said process is used to form local interconnects.
Claim 7
Dependent Claim
15 words
The process as set forth in claim 1 wherein said film also includes titanium nitride.
Claim 8
Dependent Claim
17 words
The process as set forth in claim 1 wherein said halogen containing gas is CCl 4 .
Claim 9
Dependent Claim
17 words
The process as set forth in claim 1 wherein said halogen containing gas is CF 4 .
Claim 10
Dependent Claim
15 words
The process as set forth in claim 1 wherein said gas includes an inert gas.
Claim 11
Dependent Claim
24 words
The process as set forth in claim 9 wherein said inert gas is taken from a group consisting of helium or a noble gas.
Claim 12
Dependent Claim
14 words
The process as set forth in claim 9 wherein said inert gas is helium.
Claim 13
Dependent Claim
21 words
The process as set forth in claim 1 wherein said at least free radicals and in situ plasma are generated simultaneously.
Claim 14
Dependent Claim
18 words
The process as set forth in claim 1 wherein the process is carried out at 75 degrees C.
Claim 15
Dependent Claim
17 words
The process as set forth in claim 1 wherein the process is carried out at 0.3 Torr.
Claim 16
Dependent Claim
21 words
The process as set forth in claim 9 wherein said gas includes of 70 sccm CCl 4 and 70 sccm He.
Claim 17
Dependent Claim
31 words
The process as set forth in claim 1 wherein 400 watts is used for generating said at least free radicals and 100 watts is used for generating said in situ plasma.
Claim 18
Dependent Claim
38 words
The process as set forth in claim 1 wherein a ratio of a power utilized for generating at least free radicals said at least free radicals and a power utilized for generating said in situ plasma is 4:1.
Claim 19
Dependent Claim
27 words
The process as set forth in claim 1 wherein a portion of the film is on a field oxide formed using the local oxidation of silicon method.
Claim 20
Dependent Claim
20 words
The process as set forth in claim 1 wherein a portion of the film is on a sidewall oxide filament.
Claim 21
Dependent Claim
19 words
The process as set forth in claim 1 wherein a face of the film to be processed faces downward.
Claim 22
Dependent Claim
29 words
The process as set forth in claim 1 further including a cleanup of the process chamber using free radicals generated in a plasma generator remote from the process chamber.
Claim 23
Dependent Claim
33 words
The process as set forth in claim 1 further including a cleanup of the process chamber using free radicals generated in a plasma generator remote from the process chamber and an in-situ plasma.
Claim 24
Dependent Claim
83 words
A process for etching of a titanium containing film for forming local interconnects, comprising the steps of: (a) disposing a wafer having a film at least partially comprised of titanium in a process chamber; (b) generating at least free radicals from a gas comprised of CCl 4 and an inert gas in a plasma generator remote from the process chamber; (c) introducing said free radicals to said process chamber; and (d) generating an in situ plasma within said chamber from said free radicals.
Claim 25
Dependent Claim
83 words
A process for etching of a titanium containing film for forming local interconnects, comprising the steps of: (a) disposing a wafer having a film at least partially comprised of titanium in a process chamber; (b) generating at least free radicals from a gas comprised of CCl 4 and an inert gas in a plasma generator remote from the process chamber; (c) introducing said free radicals to said process chamber; and (d) generating an in situ plasma within said chamber from said free radicals.
Claim 26
Dependent Claim
14 words
The process as set forth in claim 23 wherein said film also includes titanium-oxygen.
Claim 27
Dependent Claim
15 words
The process as set forth in claim 23 wherein said film also includes titanium silicide.
Claim 28
Dependent Claim
15 words
The process as set forth in claim 23 wherein said film also includes titanium nitride.
Claim 29
Dependent Claim
30 words
The process as set forth in claim 23 wherein said gas selectively etches one taken from the group containing titanium-oxygen, titanium, titanium nitride or a combination thereof versus titanium silicide.
Claim 30
Dependent Claim
21 words
The process as set forth in claim 23 wherein said at least free radicals and in situ plasmas are generated simultaneously.
Claim 31
Dependent Claim
18 words
The process as set forth in claim 23 wherein the process is carried out at 75 degrees C.
Claim 32
Dependent Claim
17 words
The process as set forth in claim 23 wherein the process is carried out at 0.3 Torr.
Claim 33
Dependent Claim
22 words
The process as set forth in claim 23 wherein said gas is comprised of 70 sccm CCl 4 and 70 sccm He.
Claim 34
Dependent Claim
34 words
The process as set forth in claim 23 wherein a power utilized for generating said at least free radicals is 400 watts and a power utilized for generating in situ plasma is 100 watts.
Claim 35
Dependent Claim
34 words
The process as set forth in claim 23 wherein a ratio of a power utilized for generating said at least free radicals and a power utilized for generating said in situ plasma is 4:1.
Claim 36
Dependent Claim
24 words
The process as set forth in claim 23 wherein a portion of the film is on a field oxide formed using the LOCOS method.
Claim 37
Dependent Claim
20 words
The process as set forth in claim 23 wherein a portion of the film is on a sidewall oxide filament.
Claim 38
Dependent Claim
19 words
The process as set forth in claim 23 wherein a face of the film to be processed faces downward.
Claim 39
Dependent Claim
29 words
The process as set forth in claim 23 further including a cleanup of the process chamber using free radicals generated in a plasma generator remote from the process chamber.
Claim 40
Dependent Claim
33 words
The process as set forth in claim 23 further including a cleanup of the process chamber using free radicals generated in a plasma generator remote from the process chamber and an in-situ plasma.
Claim 41
Dependent Claim
123 words
A process for etching of a titanium containing film for forming local interconnects comprising the steps of: (a) disposing a wafer having a film at least partially comprised of titanium nitride in a process chamber; (b) generating free radicals from a remote microwave plasma at a first power level from a gas comprised of CCl 4 and He; (c) generating an in situ plasma within said chamber from said free radicals using a second power level wherein the ratio of said first power level to said second power level is approximately 4:1; (d) introducing said in situ plasma to said film; and (e) cleaning the process chamber using at least the free radicals generated in the plasma generator remote from the process chamber.
Claim 42
Dependent Claim
123 words
A process for etching of a titanium containing film for forming local interconnects comprising the steps of: (a) disposing a wafer having a film at least partially comprised of titanium nitride in a process chamber; (b) generating free radicals from a remote microwave plasma at a first power level from a gas comprised of CCl 4 and He; (c) generating an in situ plasma within said chamber from said free radicals using a second power level wherein the ratio of said first power level to said second power level is approximately 4:1; (d) introducing said in situ plasma to said film; and (e) cleaning the process chamber using at least the free radicals generated in the plasma generator remote from the process chamber.
Claim 43
Dependent Claim
19 words
The process as set forth in claim 39 wherein the cleaning step includes the use of an in-situ plasma.
Claim 44
Dependent Claim
14 words
The process as set forth in claim 39 wherein said film also includes titanium-oxygen.
Claim 45
Dependent Claim
15 words
The process as set forth in claim 39 wherein said film also includes titanium silicide.
Claim 46
Dependent Claim
15 words
The process as set forth in claim 39 wherein said film also includes titanium nitride.
Claim 47
Dependent Claim
30 words
The process as set forth in claim 39 wherein said gas selectively etches one taken from the group containing titanium-oxygen, titanium, titanium nitride or a combination thereof versus titanium silicide.
Claim 48
Dependent Claim
34 words
The process as set forth in claim 39 wherein a ratio of a power utilized for generating said at least free radicals and a power utilized for generating said in situ plasma is 4:1.
Claim 49
Dependent Claim
18 words
The process as set forth in claim 39 wherein said remote and in situ plasmas are generated simultaneously.
Claim 50
Dependent Claim
22 words
The process as set forth in claim 39 wherein said wafer is removed from said process chamber prior to said cleanup step.
Claim 51
Dependent Claim
18 words
The process as set forth in claim 39 wherein the process is carried out at 75 degrees C.
Claim 52
Dependent Claim
17 words
The process as set forth in claim 39 wherein the process is carried out at 0.3 Torr.
Claim 53
Dependent Claim
22 words
The process as set forth in claim 39 wherein said gas is comprised of 70 sccm CCl 4 and 70 sccm He.
Claim 54
Dependent Claim
26 words
The process as set forth in claim 39 wherein a portion of the titanium nitride layer is on a field oxide formed using the LOCOS method.
Claim 55
Dependent Claim
22 words
The process as set forth in claim 39 wherein a portion of the titanium nitride layer is on a sidewall oxide filament.
Claim 56
Dependent Claim
19 words
The process as set forth in claim 39 wherein a face of the film to be processed faces downward.
References Cited (Backward Citations)
US4687544A
Cited
US4673456A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-11-06 | 1993-05-08 | 1993-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-06 | 1997-05-08 | 1997-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-06 | 2001-05-08 | 2001-11-07 | $7700.00 | Window Closed / Lapsed |