US5811222A
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Method of selectively exposing a material using a photosensitive layer and multiple image patterns
Assignee: Advanced Micro Devices Inc
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Filing: 1996-06-24
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Granted: 1998-09-22
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Expires: 2016-06-24
Abstract
Abstract A method of selectively exposing a material over a substrate is disclosed. The method includes forming a material over a semiconductor substrate, forming a photosensitive layer over the material, projecting a first image pattern onto the photosensitive layer that defines a first boundary for the material, projecting a second image pattern onto the photosensitive layer after projecting the first image pattern such that the second image pattern partially overlaps the first image pattern and defines a second boundary for the material, and removing portions of the photosensitive layer corresponding to the first and second image patterns. Preferably, the first and second image patterns are essentially identical to and laterally shifted with respect to one another. In this manner, the photosensitive layer selectively exposes the material adjacent to the first and second boundaries while covering the material between the first and second boundaries, and the distance between the first and second boundaries decreases as the overlap between the first and second image patterns decreases. Advantageously, the first and second boundaries can be closer than the minimum resolution of the photolithographic system used to pattern the photosensitive layer.
Inventors
- 👤 Mark I. Gardner
- 👤 Derick J. Wristers
- 👤 H. Jim Fulford, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:01
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70425; G03F7/70466; G03F7/20; G03F7/2022; G03F7/70475; H; H10; H10P; H10P76/00; H10P76/40; H10P76/408
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
127 words
A method of selectively exposing a material over a semiconductor substrate, comprising the steps of: forming a material over a semiconductor substrate; forming a photosensitive layer over the material; projecting a first image pattern onto the photosensitive layer, wherein the first image pattern defines a first boundary for the material; projecting a second image pattern onto the photosensitive layer after projecting the first image pattern, wherein the second image pattern partially overlaps the first image pattern and defines a second boundary for the material; and removing portions of the photosensitive layer corresponding to the first and second image patterns, wherein the photosensitive layer selectively exposes the material adjacent to the first and second boundaries while covering the material adjacent to and between the first and second boundaries.
Claim 2
Independent Claim
127 words
A method of selectively exposing a material over a semiconductor substrate, comprising the steps of: forming a material over a semiconductor substrate; forming a photosensitive layer over the material; projecting a first image pattern onto the photosensitive layer, wherein the first image pattern defines a first boundary for the material; projecting a second image pattern onto the photosensitive layer after projecting the first image pattern, wherein the second image pattern partially overlaps the first image pattern and defines a second boundary for the material; and removing portions of the photosensitive layer corresponding to the first and second image patterns, wherein the photosensitive layer selectively exposes the material adjacent to the first and second boundaries while covering the material adjacent to and between the first and second boundaries.
Claim 3
Dependent Claim
75 words
The method of claim 1, wherein: the first image pattern includes four inner borders having a rectangular shape within four outer borders having a rectangular shape; the second image pattern includes four inner borders having a rectangular shape within four outer borders having a rectangular shape; one of the inner borders of the first image pattern defines the first boundary; and one of the inner borders of the second image pattern defines the second boundary.
Claim 4
Dependent Claim
70 words
The method of claim 2, wherein: a first inner region within the four inner borders of the first image pattern is outside the first image pattern; a second inner region within the four inner borders of the second image pattern is outside the second image pattern; and an overlap between the first and second inner regions defines where the photoresist layer covers the material between the first and second boundaries.
Claim 5
Dependent Claim
75 words
The method of claim 1, wherein: the material includes first and second portions adjacent to and on opposite sides of a central portion, the first boundary is between the first and central portions and the second boundary is between the central and second portions; the first image pattern covers the first portion without covering the central and second portions; and the second image pattern covers the second portion without covering the first and central portions.
Claim 6
Dependent Claim
19 words
The method of claim 1, wherein the first and second image patterns are formed using separate radiation exposure steps.
Claim 7
Dependent Claim
24 words
The method of claim 1, wherein the second image pattern is essentially identical to and laterally shifted with respect to the first image pattern.
Claim 8
Dependent Claim
74 words
The method of claim 6, wherein: projecting the first image pattern onto the photosensitive layer includes projecting radiation through a reticle while the reticle has a first position with respect to the substrate; and projecting the second image pattern onto the photosensitive layer includes projecting radiation through the reticle while the reticle has a second position with respect to the substrate, wherein the second position is laterally shifted with respect to the first position.
Claim 9
Dependent Claim
68 words
The method of claim 6, wherein: projecting the first image pattern onto the photosensitive layer includes projecting radiation through a first reticle having a first radiation-transmitting pattern; and projecting the second image pattern onto the photosensitive layer includes projecting radiation through a second reticle having a second radiation-transmitting pattern, wherein the second radiation-transmitting pattern is essentially identical to and laterally shifted with respect to the first radiation-transmitting pattern.
Claim 10
Dependent Claim
25 words
The method of claim 6, wherein the second image pattern is laterally shifted with respect to the first image pattern along a single coordinate axis.
Claim 11
Dependent Claim
28 words
The method of claim 6, wherein the second image pattern is laterally shifted with respect to the first image pattern along first and second mutually orthogonal coordinate axes.
Claim 12
Dependent Claim
41 words
The method of claim 1, including applying an etch to selectively remove portions of the material that are selectively exposed by the photosensitive layer, thereby forming first and second edges in the material corresponding to the first and second boundaries, respectively.
Claim 13
Dependent Claim
16 words
The method of claim 1, wherein the photosensitive layer is photoresist and the material is polysilicon.
Claim 14
Dependent Claim
14 words
The method of claim 1, performed during the fabrication of an integrated circuit chip.
Claim 15
Dependent Claim
23 words
The method of claim 1, performed during the fabrication of an electronic system that includes a microprocessor, a memory and a system bus.
Claim 16
Independent Claim
157 words
A method of selectively exposing a material over a semiconductor substrate, comprising the steps of: forming a material over a semiconductor substrate, wherein the material includes a central portion between and adjacent to first and second portions; forming a positive photoresist layer on the material; projecting a first image pattern onto the photoresist layer, wherein the first image pattern covers the first portion without covering the central and second portions; projecting a second image pattern onto the photoresist layer after projecting the first image pattern, wherein the second image is essentially identical to and laterally shifted with respect to the first image pattern, the second image pattern partially overlaps the first image pattern, and the second image pattern covers the second portion without covering the first and central portions; and removing portions of the photoresist layer corresponding to the first and second image patterns to selectively expose the first and second portions without exposing the central portion.
Claim 17
Independent Claim
157 words
A method of selectively exposing a material over a semiconductor substrate, comprising the steps of: forming a material over a semiconductor substrate, wherein the material includes a central portion between and adjacent to first and second portions; forming a positive photoresist layer on the material; projecting a first image pattern onto the photoresist layer, wherein the first image pattern covers the first portion without covering the central and second portions; projecting a second image pattern onto the photoresist layer after projecting the first image pattern, wherein the second image is essentially identical to and laterally shifted with respect to the first image pattern, the second image pattern partially overlaps the first image pattern, and the second image pattern covers the second portion without covering the first and central portions; and removing portions of the photoresist layer corresponding to the first and second image patterns to selectively expose the first and second portions without exposing the central portion.
Claim 18
Dependent Claim
90 words
The method of claim 15, wherein: projecting the first image pattern onto the photoresist layer includes projecting radiation through a reticle while the reticle has a first position with respect to the substrate; and projecting the second image pattern onto the photoresist layer includes projecting radiation through the reticle while the reticle has a second position with respect to the substrate, wherein the second position is laterally shifted with respect to the first position so as to laterally shift the second image pattern with respect to the first image pattern.
Claim 19
Dependent Claim
84 words
The method of claim 15, wherein: projecting the first image pattern onto the photoresist layer includes projecting radiation through a first reticle having a first radiation-transmitting pattern; and projecting the second image pattern onto the photoresist layer includes projecting radiation through a second reticle having a second radiation-transmitting pattern, wherein the second radiation-transmitting pattern is essentially identical to and laterally shifted with respect to the first radiation-transmitting pattern so as to laterally shift the second image pattern with respect to the first image pattern.
Claim 20
Dependent Claim
25 words
The method of claim 15, wherein the second image pattern is laterally shifted with respect to the first image pattern along a single coordinate axis.
Claim 21
Dependent Claim
28 words
The method of claim 15, wherein the second image pattern is laterally shifted with respect to the first image pattern along first and second mutually orthogonal coordinate axes.
Claim 22
Dependent Claim
10 words
The method of claim 15, wherein the material is polysilicon.
Claim 23
Dependent Claim
23 words
The method of claim 15, wherein the first and second portions are etched and removed, and the central portion forms a gate electrode.
Claim 24
Dependent Claim
40 words
The method of claim 15, wherein a length across the central portion between the first and second portions is less than a minimum resolution of a photolithographic system that projects the first and second image patterns onto the photoresist layer.
Claim 25
Dependent Claim
14 words
The method of claim 22, wherein the length is less than about 0.4 microns.
Claim 26
Dependent Claim
14 words
The method of claim 22, wherein the length is less than about 0.2 microns.
Claim 27
Independent Claim
214 words
A method of selectively exposing a gate material for forming a gate electrode for an IGFET, comprising the following steps in the sequence set forth: forming a gate oxide on a semiconductor substrate; forming a polysilicon layer on the gate oxide, wherein the polysilicon layer includes a gate electrode and first and second portions adjacent to opposite ends of the gate electrode; forming a positive photoresist layer on the polysilicon layer; projecting a first image pattern onto the photoresist layer using a first radiation exposure, wherein the first image pattern defines a first edge for the gate electrode by covering the first portion without covering the gate electrode and without covering the second portion; projecting a second image pattern onto the photoresist layer using a second radiation exposure, wherein the second image pattern defines a second edge for the gate electrode by covering the second portion without covering the first portion and without covering the gate electrode, the second image pattern partially overlaps the first image pattern, and the second image pattern is essentially identical to and laterally shifted with respect to the first image pattern; and removing portions of the photoresist layer corresponding to the first and second image patterns to selectively expose the first and second portions while covering the gate electrode.
Claim 28
Independent Claim
214 words
A method of selectively exposing a gate material for forming a gate electrode for an IGFET, comprising the following steps in the sequence set forth: forming a gate oxide on a semiconductor substrate; forming a polysilicon layer on the gate oxide, wherein the polysilicon layer includes a gate electrode and first and second portions adjacent to opposite ends of the gate electrode; forming a positive photoresist layer on the polysilicon layer; projecting a first image pattern onto the photoresist layer using a first radiation exposure, wherein the first image pattern defines a first edge for the gate electrode by covering the first portion without covering the gate electrode and without covering the second portion; projecting a second image pattern onto the photoresist layer using a second radiation exposure, wherein the second image pattern defines a second edge for the gate electrode by covering the second portion without covering the first portion and without covering the gate electrode, the second image pattern partially overlaps the first image pattern, and the second image pattern is essentially identical to and laterally shifted with respect to the first image pattern; and removing portions of the photoresist layer corresponding to the first and second image patterns to selectively expose the first and second portions while covering the gate electrode.
Claim 29
Dependent Claim
236 words
The method of claim 25, wherein: the first and second image patterns each include four inner borders within four outer borders; the inner borders include a first inner border adjacent to a second inner border, a third inner border adjacent to the second inner border and opposing the first inner border, and a fourth inner border adjacent to the first and third inner borders and opposing the second inner border; the outer borders include a first outer border adjacent to a second outer border, a third outer border adjacent to the second outer border and opposing the first outer border, and a fourth outer border adjacent to the first and third outer borders and opposing the second outer border; the first and third inner borders of the second image pattern are laterally shifted along a first coordinate axis with respect to the first and third inner borders of the first image pattern, wherein the first coordinate axis is orthogonal to a second coordinate axis; the first and third outer borders of the second image pattern are laterally shifted along the first coordinate axis with respect to the first and third outer borders of the first image pattern; the first edge of the gate electrode is defined by the third inner border of the first image pattern; and the second edge of the gate electrode is defined by the first inner border of the second image pattern.
Claim 30
Dependent Claim
67 words
The method of claim 26, wherein: the second and fourth inner borders of the second image pattern are aligned along the second coordinate axis with the second and fourth inner borders of the first image pattern; and the second and fourth outer borders of the second image pattern are aligned along the second coordinate axis with the second and fourth outer borders of the first image pattern.
Claim 31
Dependent Claim
73 words
The method of claim 26, wherein: the second and fourth inner borders of the second image pattern are laterally shifted along the second coordinate axis with respect to the second and fourth inner borders of the first image pattern; and the second and fourth outer borders of the second image pattern are laterally shifted along the second coordinate axis with respect to the second and fourth outer borders of the first image pattern.
Claim 32
Dependent Claim
51 words
The method of claim 26, wherein a length of the gate electrode between the first and second edges is equivalent to a distance between the first and third inner borders of the first image pattern minus the lateral shift along the first coordinate axis between the first and second image patterns.
Claim 33
Dependent Claim
54 words
The method of claim 26, wherein a width of the gate electrode parallel to the first and second edges is equivalent to a distance between the second and fourth inner borders of the first image pattern minus the lateral shift, if any, along the second coordinate axis between the first and second image patterns.
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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) | 2001-09-21 | 2002-03-23 | 2002-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-09-21 | 2006-03-23 | 2006-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-09-21 | 2010-03-23 | 2010-09-22 | $7700.00 | Window Closed / Lapsed |