US6355567B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Retrograde openings in thin films
Assignee: International Business Machines Corp
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Filing: 1999-06-30
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Granted: 2002-03-12
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Expires: 2019-06-30
Abstract
Abstract Retrograde openings in thin films and the process for forming the same. The openings may include conductive materials formed within the openings to serve as a wiring pattern which includes wires having tapered cross sections. The process involves a two-step etching procedure for forming a retrograde opening within a film having a gradient of a characteristic that influences the etch rate for a chosen etchant species. An opening is first formed within the film by an anisotropic etch process. The opening is then converted to an opening including retrograde features by an isotropic etch process which is selective to the characteristic. Thereafter, the retrograde opening is filled with a conductive material, in one case, by electroplating or other deposition techniques.
Inventors
- 👤 Scott D. Halle
- 👤 Paul C. Jamison
- 👤 David E. Kotecki
- 👤 Richard S. Wise
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:05
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/056; H10W20/057; H10W20/063; H10W20/071; H10W20/072; H10W20/081; H10W20/082; H10W20/40; H10W20/45; H10W20/46; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H10W20/41; H10W20/435
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
146 words
A process for forming a retrograde opening in a film, comprising the steps of; (a) forming a film having: (1) a top, (2) bottom, and (3) characteristic that varies in the same sense from the top of the film to the bottom of the film; (b) applying a first etchant to anisotropically etch an opening in the film extending downward from the top of the film; and (c) applying a second etchant: (1) to isotropically etch the opening in the film, and (2) having a composition based on the characteristic of the film to produce further etching of the film at a first etch rate at a lower portion of the opening that is greater than a second etch rate at a higher portion of the opening resulting in a tapered retrograde opening having a top width and a bottom width greater than the top width.
Claim 2
Dependent Claim
146 words
A process for forming a retrograde opening in a film, comprising the steps of; (a) forming a film having: (1) a top, (2) bottom, and (3) characteristic that varies in the same sense from the top of the film to the bottom of the film; (b) applying a first etchant to anisotropically etch an opening in the film extending downward from the top of the film; and (c) applying a second etchant: (1) to isotropically etch the opening in the film, and (2) having a composition based on the characteristic of the film to produce further etching of the film at a first etch rate at a lower portion of the opening that is greater than a second etch rate at a higher portion of the opening resulting in a tapered retrograde opening having a top width and a bottom width greater than the top width.
Claim 3
Dependent Claim
14 words
The process as in claim 1 , wherein the characteristic comprises a dopant concentration.
Claim 4
Dependent Claim
44 words
The process as in claim 1 , wherein the characteristic is one of (a) increasing continuously from the top of the film to the bottom of the film, and (b) decreasing continuously from the top of the film to the bottom of the film.
Claim 5
Dependent Claim
20 words
The process as in claim 1 , wherein the characteristic comprises a relative amount of a constituent of the film.
Claim 6
Dependent Claim
21 words
The process as in claim 1 , wherein the step (b) comprises reactive ion etching which is non-selective to the characteristic.
Claim 7
Dependent Claim
38 words
The process as in claim 1 , further comprising the step (a1) of forming a pattern in a masking film placed on the film, and wherein the step (b) comprises anisotropically etching using a reactive ion etching technique.
Claim 8
Dependent Claim
36 words
The process as in claim 1 , wherein the step (a) comprises sequentially forming a plurality of film sub-layers and doping each film sub-layer with a corresponding dopant concentration, and the characteristic comprises the dopant concentration.
Claim 9
Dependent Claim
43 words
The process as in claim 1 , wherein the step (a) comprises sequentially forming a plurality of film layers, each film layer formed of a plurality of components, and the characteristic comprises an amount of a first component within a corresponding film layer.
Claim 10
Dependent Claim
15 words
The process as in claim 1 , wherein the step (c) comprises dry chemical etching.
Claim 11
Dependent Claim
15 words
The process as in claim 1 , wherein the step (c) comprises wet chemical etching.
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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) | 2005-03-11 | 2005-09-10 | 2006-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-03-11 | 2009-09-10 | 2010-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-03-11 | 2013-09-10 | 2014-03-12 | $7700.00 | Window Closed / Lapsed |