US5108951A
Expired / Lapsed
US
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Method for forming a metal contact
Assignee: STMicroelectronics lnc USA
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Filing: 1990-11-05
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Granted: 1992-04-28
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Expires: 2010-11-05
Abstract
Abstract A method is provided for depositing aluminum thin film layers to form improved quality contacts in a semiconductor integrated circuit device. All or some of the deposition process occurs at relatively low deposition rates at a temperature which allows improved surface migration of the deposited aluminum atoms. Aluminum deposited under these conditions tends to fill contact vias without the formation of voids. The low temperature deposition step can be initiated by depositing aluminum while a wafer containing the integrated circuit device is being heated from cooler temperatures within the deposition chamber.
Inventors
- 👤 Fusen E. Chen
- 👤 Fu-Tai Liou
- 👤 Yih-Shung Lin
- 👤 Girish A. Dixit
- 👤 Che-Chia Wei
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:11
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/40; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/032; H10W20/033; C; C23; C23C; C23C16/00; C23C16/02; C23C16/0272; C23C16/0281; C23C16/06; C23C16/18; C23C16/20; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10P14/412; H10W20/056; H10W20/40; H10W20/41; H10W20/425
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
69 words
A method for depositing an aluminum layer on a semiconductor integrated circuit, comprising the steps of: increasing the temperature of the integrated circuit to a temperature less than approximately 500° C.; and beginning to deposit aluminum on the integrated circuit simultaneously with the increase in the temperature at a rate which is low enough to allow surface migration of deposited aluminum to fill low regions in the integrated circuit.
Claim 2
Independent Claim
69 words
A method for depositing an aluminum layer on a semiconductor integrated circuit, comprising the steps of: increasing the temperature of the integrated circuit to a temperature less than approximately 500° C.; and beginning to deposit aluminum on the integrated circuit simultaneously with the increase in the temperature at a rate which is low enough to allow surface migration of deposited aluminum to fill low regions in the integrated circuit.
Claim 3
Dependent Claim
20 words
The method of claim 1, wherein the temperature increases to a value between approximately 380° C. and approximately 500° C.
Claim 4
Dependent Claim
19 words
The method of claim 2, wherein the temperature increases to a value between approximately 420° C. and 460° C.
Claim 5
Dependent Claim
16 words
The method of claim 3, wherein the temperature increases to a value of approximately 450° C.
Claim 6
Dependent Claim
18 words
The method of claim 1, wherein the rate of deposition of aluminum is less than approximately 100 angstroms/sec.
Claim 7
Dependent Claim
22 words
The method of claim 1, wherein the rate of deposition for aluminum is changed at least once during the depositing aluminum step.
Claim 8
Dependent Claim
31 words
The method of claim 6, wherein the rate of deposition of aluminum is less during a middle deposition period than during a beginning deposition period and during an ending deposition period.
Claim 9
Dependent Claim
33 words
The method of claim 7, wherein the deposition rate is less than approximately 40 angstroms/sec during the middle deposition period, and greater than approximately 50 angstroms/sec during the beginning and ending deposition periods.
Claim 10
Dependent Claim
21 words
The method of claim 8, wherein the aluminum deposition rate during the ending deposition period is greater than approximately 100 angstroms/sec.
Claim 11
Dependent Claim
22 words
The method of claim 1, wherein aluminum is deposited at a rate which lies within the selected region 32 of FIG. 3.
Claim 12
Independent Claim
139 words
A method for forming an aluminum contact in an integrated circuit, comprising the steps of: forming an insulating layer over a conducting layer; forming an opening through the insulating layer to expose a portion of the conducting layer; raising the temperature of the integrated circuit from below approximately 350° C. to a value between approximately 400° C. and approximately 500° C.; during said temperature raising step, depositing aluminum continuously on the integrated circuit, wherein the depositing aluminum step begins simultaneously with the beginning of the temperature raising step; after said temperature raising step, continuing to deposit an aluminum layer on the integrated circuit to a desired thickness; during said desired thickness depositing step, controlling the rate at which aluminum is deposited to allow deposited aluminum to migrate into the opening so as to provide a substantially complete fill thereof.
Claim 13
Independent Claim
139 words
A method for forming an aluminum contact in an integrated circuit, comprising the steps of: forming an insulating layer over a conducting layer; forming an opening through the insulating layer to expose a portion of the conducting layer; raising the temperature of the integrated circuit from below approximately 350° C. to a value between approximately 400° C. and approximately 500° C.; during said temperature raising step, depositing aluminum continuously on the integrated circuit, wherein the depositing aluminum step begins simultaneously with the beginning of the temperature raising step; after said temperature raising step, continuing to deposit an aluminum layer on the integrated circuit to a desired thickness; during said desired thickness depositing step, controlling the rate at which aluminum is deposited to allow deposited aluminum to migrate into the opening so as to provide a substantially complete fill thereof.
Claim 14
Dependent Claim
35 words
The method of claim 11, wherein said controlling step comprises the step of: maintaining the deposition rate to be less than approximately (0.7*T)-250 angstroms/sec where T lies between approximately 400° C. and approximately 500° C.
Claim 15
Dependent Claim
29 words
The method of claim 11, wherein the deposition rate is varied, with one portion being faster than approximately 50 angstroms/sec, and another portion being slower than approximately 50 angstroms/sec.
Claim 16
Dependent Claim
24 words
The method of claim 13, wherein a last portion of said deposition step is performed at a deposition rate faster than approximately 100 angstroms/sec.
Claim 17
Dependent Claim
31 words
The method of claim 13, wherein one deposition portion is performed at a rate above approximately 60 angstroms/sec, and another deposition portion is performed at a rate below approximately 40 angstroms/sec.
Claim 18
Independent Claim
175 words
A method for forming an aluminum contact in an integrated circuit, comprising the steps of: forming an insulating layer over a conducting layer; forming an opening through the insulating layer to expose a portion of the conducting layer; forming a barrier layer over the insulating layer, in the opening and the exposed portion of the conducting layer; beginning to deposit aluminum at a temperature below approximately 350° C. on the barrier layer at a relatively low rate of deposition; simultaneously with said beginning to deposit aluminum step, beginning to raise the temperature of the integrated circuit; continuing to deposit aluminum while increasing the temperature from below approximately 350° C. to a desired temperature between approximately 400° C. and approximately 500° C.; after the integrated circuit temperature has reached the desired temperature, depositing an aluminum layer on the integrated circuit to a desired thickness; during said desired thickness depositing step, controlling the rate at which aluminum is deposited to allow deposited aluminum to migrate into the opening so as to provide a substantially complete fill thereof.
Claim 19
Independent Claim
175 words
A method for forming an aluminum contact in an integrated circuit, comprising the steps of: forming an insulating layer over a conducting layer; forming an opening through the insulating layer to expose a portion of the conducting layer; forming a barrier layer over the insulating layer, in the opening and the exposed portion of the conducting layer; beginning to deposit aluminum at a temperature below approximately 350° C. on the barrier layer at a relatively low rate of deposition; simultaneously with said beginning to deposit aluminum step, beginning to raise the temperature of the integrated circuit; continuing to deposit aluminum while increasing the temperature from below approximately 350° C. to a desired temperature between approximately 400° C. and approximately 500° C.; after the integrated circuit temperature has reached the desired temperature, depositing an aluminum layer on the integrated circuit to a desired thickness; during said desired thickness depositing step, controlling the rate at which aluminum is deposited to allow deposited aluminum to migrate into the opening so as to provide a substantially complete fill thereof.
Claim 20
Dependent Claim
16 words
The method of claim 16, wherein the barrier layer comprises a refractory metal/refractory metal nitride composite.
Claim 21
Dependent Claim
17 words
The method of claim 16, wherein the barrier layer comprises a refractory metal/refractory metal nitride/refractory metal composite.
Claim 22
Dependent Claim
32 words
The method of claim 11, wherein the depositing aluminum step is performed at a first deposition rate which is changed to a second rate before the integrated circuit reaches the desired temperature.
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) | 1995-04-28 | 1995-10-28 | 1996-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-04-28 | 1999-10-28 | 2000-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-04-28 | 2003-10-28 | 2004-04-28 | $7700.00 | Window Closed / Lapsed |