US5858877A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-aligned process for making contacts to silicon substrates during the manufacture of integrated circuits therein
Assignee: Round Rock Research LLC
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Filing: 1997-01-21
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Granted: 1999-01-12
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Expires: 2017-01-21
Abstract
Abstract A process for forming vertical contacts in the manufacture of integrated circuits, and devices so manufactured. The process eliminates the need for precise mask alignment and allows the etch of the contact hole to be controlled independent of the etch of the interconnect trough. The process includes the steps of: forming an insulating layer on the surface of a substrate; forming an etch stop layer on the surface of the insulating layer; forming an opening in the etch stop layer; etching to a first depth through the opening in the etch stop layer and into the insulating layer to form an interconnect trough; forming a photoresist mask on the surface of the etch stop layer and in the trough; and continuing to etch through the insulating layer until reaching the surface of the substrate to form a contact hole. The above process may be repeated one or more times during the formation of multi-level metal integrated circuits.
Inventors
- 👤 Charles H. Dennison
- 👤 Trung T. Doan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:30
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/73; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/081; H10W20/084; H10W20/085; H10W20/074; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/948; Y10S438/95; Y10S438/97
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
139 words
A process for forming electrical contacts for integrated circuits, comprising the steps of: a. forming a first layer on a substrate; b. forming an etch stop layer consisting of an inorganic compound on the first layer, the etch stop layer being selectively etchable with respect to the first layer; c. forming an opening in the etch stop layer at a desired location of a trough; d. etching the first layer through the opening to a first depth to form a trough; e. forming a mask over the trough and the etch stop layer; f. selectively removing the mask to expose portions of the first layer within the trough at a desired location of a contact hole; g. etching the exposed portions of the first layer to a second depth to form a contact hole; and h. removing the mask.
Claim 2
Dependent Claim
139 words
A process for forming electrical contacts for integrated circuits, comprising the steps of: a. forming a first layer on a substrate; b. forming an etch stop layer consisting of an inorganic compound on the first layer, the etch stop layer being selectively etchable with respect to the first layer; c. forming an opening in the etch stop layer at a desired location of a trough; d. etching the first layer through the opening to a first depth to form a trough; e. forming a mask over the trough and the etch stop layer; f. selectively removing the mask to expose portions of the first layer within the trough at a desired location of a contact hole; g. etching the exposed portions of the first layer to a second depth to form a contact hole; and h. removing the mask.
Claim 3
Dependent Claim
14 words
A process according to claim 1, wherein the first layer comprises electrically insulating material.
Claim 4
Dependent Claim
24 words
A process according to claim 1, wherein the inorganic compound is selected from the group consisting of silicon nitride, titanium, oxide and aluminum oxide.
Claim 5
Dependent Claim
23 words
A process according to claim 1, further comprising the step of forming an adhesion layer on the surfaces of each hole and trough.
Claim 6
Dependent Claim
30 words
A process according to claim 4, further comprising the step of filling each hole and trough at least partially with electrically conductive material after the adhesion later has been formed.
Claim 7
Dependent Claim
23 words
A process according to claim 1, further comprising the step of filling each hole and trough at least partially with electrically conductive material.
Claim 8
Dependent Claim
29 words
A process according to claim 6, further comprising the step of making an upper surface of the conductive material coplanar with an upper surface of the etch stop layer.
Claim 9
Dependent Claim
16 words
A process according to claim 6, further comprising the step of removing the etch stop layer.
Claim 10
Dependent Claim
28 words
A process according to claim 8, further comprising the step of making an upper surface of the conductive material coplanar with an upper surface of the first layer.
Claim 11
Dependent Claim
28 words
A process according to claim 1, wherein the process steps are repeated through a plurality of first layers to form multi-level metal vias in a multi-level integrated circuit.
Claim 12
Dependent Claim
122 words
A process for forming electrical contacts for integrated circuits, comprising the steps of: a. forming a first layer of etchable material; b. forming an etch stop layer consisting of an inorganic compound having an opening therein on the first layer, wherein the opening defines a width dimension of a trough and a contact hole; c. etching the first layer through the opening to a first depth to form a trough; d. forming a mask over the trough and the etch stop layer; e. selectively removing the mask to expose a portion of the first layer at a desired location of a contact hole; and f. etching the exposed portion of the first layer to a second depth to form a contact hole.
Claim 13
Dependent Claim
122 words
A process for forming electrical contacts for integrated circuits, comprising the steps of: a. forming a first layer of etchable material; b. forming an etch stop layer consisting of an inorganic compound having an opening therein on the first layer, wherein the opening defines a width dimension of a trough and a contact hole; c. etching the first layer through the opening to a first depth to form a trough; d. forming a mask over the trough and the etch stop layer; e. selectively removing the mask to expose a portion of the first layer at a desired location of a contact hole; and f. etching the exposed portion of the first layer to a second depth to form a contact hole.
Claim 14
Dependent Claim
22 words
A process according to claim 11, wherein step (e) further comprises exposing a portion of the etch stop layer adjacent the opening.
Claim 15
Dependent Claim
60 words
A process according to claim 11, further comprising the steps of: a. forming an etch stop mask over the etch stop layer; b. selectively removing the etch stop mask to expose portions of the etch stop layer at a desired location of a trough; and c. etching the exposed portions of the etch stop layer to form the opening therein.
Claim 16
Dependent Claim
146 words
A process for forming electrical contacts for integrated circuits, comprising the steps of: a. forming a first layer on a substrate; b. forming an etch stop layer on the first layer, the etch stop layer being selectively etchable with respect to the first layer; c. forming an opening in the etch stop layer at a desired location of a trough using a first mask; d. etching the first layer through the opening to a first depth to form a trough; e. forming a second mask over the trough and the etch stop layer after removing the first mask; f. selectively removing the second mask to expose portions of the first layer within the trough at a desired location of a contact hole; g. etching the exposed portions of the first layer to a second depth to form a contact hole, and h. removing the second mask.
Claim 17
Dependent Claim
146 words
A process for forming electrical contacts for integrated circuits, comprising the steps of: a. forming a first layer on a substrate; b. forming an etch stop layer on the first layer, the etch stop layer being selectively etchable with respect to the first layer; c. forming an opening in the etch stop layer at a desired location of a trough using a first mask; d. etching the first layer through the opening to a first depth to form a trough; e. forming a second mask over the trough and the etch stop layer after removing the first mask; f. selectively removing the second mask to expose portions of the first layer within the trough at a desired location of a contact hole; g. etching the exposed portions of the first layer to a second depth to form a contact hole, and h. removing the second mask.
Claim 18
Dependent Claim
26 words
A process according to claim 14, wherein the step of selectively removing the second mask comprises exposing a portion of the etch stop layer-adjacent the opening.
Claim 19
Dependent Claim
14 words
A process according to claim 14, wherein the first layer comprises electrically insulating material.
Claim 20
Dependent Claim
28 words
A process according to claim 14, wherein the etch stop layer comprises an inorganic compound selected from the group consisting of silicon nitride, titanium oxide and aluminum oxide.
Claim 21
Dependent Claim
23 words
A process according to claim 14, further comprising the step of forming an adhesion layer on the surface of each hole and trough.
Claim 22
Dependent Claim
29 words
A process according to claim 18 further comprising the step of filling each hole and trough at least partially with electrically conductive material after,the adhesion layer has been formed.
Claim 23
Dependent Claim
23 words
A process according to claim 14, further comprising the step of filling each hole and trough at least partially with electrically conductive material.
Claim 24
Dependent Claim
29 words
A process according to claim 20, further comprising the step of making an upper surface of the conductive material coplanar with an upper surface of the etch stop layer.
Claim 25
Dependent Claim
16 words
A process according to claim 20, further comprising the step of removing the etch stop layer.
Claim 26
Dependent Claim
27 words
A process according to claim 22, further comprising the step of making upper surface of the conductive material coplanar with an upper surface of the first layer.
Claim 27
Dependent Claim
27 words
A process according to claim 14, wherein the process steps are repeated through a plurality of first layers to form multi-level vias in a multi-level integrated circuit.
References Cited (Backward Citations)
US5354711A
Cited
US5126006A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-01-11 | 2002-07-13 | 2003-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-01-11 | 2006-07-13 | 2007-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-01-11 | 2010-07-13 | 2011-01-12 | $7700.00 | Window Closed / Lapsed |