US5278098A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for self-aligned polysilicon contact formation
Assignee: STMicroelectronics lnc USA
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Filing: 1992-09-03
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Granted: 1994-01-11
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Expires: 2012-09-03
Abstract
Abstract A polycrystalline silicon layer is deposited and patterned to define a level of interconnect. Contact openings to lower conductive layers are then defined and patterned. A refractory metal such as tungsten is selectively deposited over the device, so that it adheres to the polycrystalline silicon in the interconnect leads and silicon of the lower conductive layer which is exposed in the contact openings. This provides a low resistance interconnect, and good, metal, contacts to underlying layers. Shared contacts between two or more polycrystalline silicon interconnect layers and in underlying conductive layers such as a substrate are easily formed using this technique.
Inventors
- 👤 Che C. Wei
- 👤 Chiara Zaccherini
- 👤 Robert O. Miller
- 👤 Girish A. Dixit
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:30
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/011; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/064; H10W20/066; H10D64/0111; H10D64/0113; H10W20/069; H10W20/0698; H10W20/40; H10W20/41; H10W20/44; H10W20/4451
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
214 words
A method for forming a contact on an integrated circuit, comprising the steps of: forming a first insulating layer over the integrated circuit; forming a first polycrystalline silicon layer over the first insulating layer; patterning the first polycrystalline silicon layer to define a first interconnect layer; forming a second insulating layer over the integrated circuit; forming a second polycrystalline silicon layer over the second insulating layer; patterning the second polycrystalline silicon layer to define a second interconnect layer; depositing a masking layer over the integrated circuit and patterning the masking layer to define a location for an opening to be formed, wherein a portion of the first and second interconnect layers project into the location for the opening; forming an opening through the first and second insulating layers to expose a portion of the first interconnect layer and conducting regions in the integrated circuit; and selectively depositing a first metallic conducting layer over the integrated circuit so that a metallic conductor forms on top and sides of the first interconnect layer exposed in the opening, on top and sides of the second interconnect layer exposed in the opening, and on the exposed conducting regions, wherein the metallic conductor forms a common conducting contact between the conducting regions and the first and second interconnect layers.
Claim 2
Independent Claim
214 words
A method for forming a contact on an integrated circuit, comprising the steps of: forming a first insulating layer over the integrated circuit; forming a first polycrystalline silicon layer over the first insulating layer; patterning the first polycrystalline silicon layer to define a first interconnect layer; forming a second insulating layer over the integrated circuit; forming a second polycrystalline silicon layer over the second insulating layer; patterning the second polycrystalline silicon layer to define a second interconnect layer; depositing a masking layer over the integrated circuit and patterning the masking layer to define a location for an opening to be formed, wherein a portion of the first and second interconnect layers project into the location for the opening; forming an opening through the first and second insulating layers to expose a portion of the first interconnect layer and conducting regions in the integrated circuit; and selectively depositing a first metallic conducting layer over the integrated circuit so that a metallic conductor forms on top and sides of the first interconnect layer exposed in the opening, on top and sides of the second interconnect layer exposed in the opening, and on the exposed conducting regions, wherein the metallic conductor forms a common conducting contact between the conducting regions and the first and second interconnect layers.
Claim 3
Dependent Claim
20 words
The method of claim 1, wherein the exposed conducting regions are formed in a substrate of a semiconductor integrated circuit.
Claim 4
Dependent Claim
26 words
The method of claim 1, further comprising the step of: before said patterning step, introducing an impurity into said polycrystalline silicon layer to improve its conductivity.
Claim 5
Independent Claim
191 words
A method for forming a contact for an integrated circuit, comprising the steps of: forming a first insulating layer over the integrated circuit; forming a first polycrystalline silicon layer over the first insulating layer; patterning the first polycrystalline silicon layer to define a first interconnect layer; forming a second insulating layer over the first interconnect layer and the first insulating layer; forming a second polycrystalline silicon layer over the second insulating layer; patterning the second polycrystalline silicon layer to define a second interconnect layer; depositing a masking layer over the integrated circuit and patterning the masking layer to define a location for an opening to be formed, wherein a portion of the first and second interconnect layers project into the location for an opening; forming an opening through the first and second insulating layers to expose conducting regions below the first insulating layer and portions of the first interconnect layer; and selectively depositing a metallic conductor on the exposed conducting regions and exposed portions of the first and second interconnect layers, wherein the metallic conductor forms a common conducting contact between the conducting regions and the first and second interconnect layers.
Claim 6
Independent Claim
191 words
A method for forming a contact for an integrated circuit, comprising the steps of: forming a first insulating layer over the integrated circuit; forming a first polycrystalline silicon layer over the first insulating layer; patterning the first polycrystalline silicon layer to define a first interconnect layer; forming a second insulating layer over the first interconnect layer and the first insulating layer; forming a second polycrystalline silicon layer over the second insulating layer; patterning the second polycrystalline silicon layer to define a second interconnect layer; depositing a masking layer over the integrated circuit and patterning the masking layer to define a location for an opening to be formed, wherein a portion of the first and second interconnect layers project into the location for an opening; forming an opening through the first and second insulating layers to expose conducting regions below the first insulating layer and portions of the first interconnect layer; and selectively depositing a metallic conductor on the exposed conducting regions and exposed portions of the first and second interconnect layers, wherein the metallic conductor forms a common conducting contact between the conducting regions and the first and second interconnect layers.
Claim 7
Dependent Claim
20 words
The method of claim 4, wherein the exposed conducting regions are formed in a substrate of a semiconductor integrated circuit.
Claim 8
Dependent Claim
26 words
The method of claim 4, further comprising the step of: before said patterning step, introducing an impurity into said polycrystalline silicon layer to improve its conductivity.
Claim 9
Dependent Claim
48 words
The method of claim 4, further comprising the step of forming a third insulating layer over the integrated circuit prior to said step of forming the opening, wherein said step of forming the opening exposes the conducting regions and a portion of the first and second interconnect layers.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-01-10 | 1997-07-12 | 1998-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-01-10 | 2001-07-12 | 2002-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-01-10 | 2005-07-12 | 2006-01-11 | $7700.00 | Window Closed / Lapsed |