US6447964B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Charged-particle-beam microlithography methods including chip-exposure sequences for reducing thermally induced lateral shift of exposure position on the substrate
Assignee: Nikon Corp
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Filing: 2001-02-27
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Granted: 2002-09-10
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Expires: 2021-02-27
Abstract
Abstract Methods are disclosed for reducing effects of thermal expansion of a sensitive substrate arising during microlithographic exposure of the substrate using a charged particle beam. Thermal expansion ordinarily causes lateral shift of exposure position of dies (chips) on the substrate which tends to reduce the positional accuracy with which images of the dies are formed on the substrate. Generally, regions of the substrate where entire dies are formed are exposed first, followed by regions (especially peripheral regions) exposed with only portions of dies. In addition, the substrate can be mounted on a wafer chuck configured to circulate a heat-transfer gas in contact with the substrate to remove heat from the substrate. In addition, the wafer chuck can be maintained at a constant temperature by circulating a liquid coolant through a conduit in the body of the wafer chuck.
Inventors
- 👤 Teruaki Okino
- 👤 Tomoharu Fujiwara
- 👤 Noriyuki Hirayanagi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 07:43
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/30; H01J37/317; H01J37/3174; B; B82; B82Y; B82Y10/00; B82Y40/00; H01J2237/00; H01J2237/30; H01J2237/304; H01J2237/30455; H01J2237/317; H01J2237/3175; H01J2237/31761; H01J2237/31764; Y; Y10; Y10S; Y10S430/00; Y10S430/143
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
151 words
In a microlithography method in which a die pattern, defined on a segmented reticle including multiple stripes defining respective portions of the pattern, is projection-transferred stripe-by-stripe to a chip region on a sensitive surface of a substrate using a charged particle beam, a method for reducing thermal expansion of the substrate during exposure, comprising: (a) determining a magnitude of thermal expansion of the substrate that would occur if a chip region on the substrate were exposed with the stripes in a first stripe-exposure sequence; (b) determining a magnitude of thermal expansion of the substrate that would occur if the chip region were exposed with the stripes in a second stripe-exposure sequence different from the first stripe-exposure sequence; and (c) if the magnitude of thermal expansion determined in step (b) is lower than the magnitude of thermal expansion determined in step (a), then exposing the chip region using the second stripe-exposure sequence.
Claim 2
Dependent Claim
151 words
In a microlithography method in which a die pattern, defined on a segmented reticle including multiple stripes defining respective portions of the pattern, is projection-transferred stripe-by-stripe to a chip region on a sensitive surface of a substrate using a charged particle beam, a method for reducing thermal expansion of the substrate during exposure, comprising: (a) determining a magnitude of thermal expansion of the substrate that would occur if a chip region on the substrate were exposed with the stripes in a first stripe-exposure sequence; (b) determining a magnitude of thermal expansion of the substrate that would occur if the chip region were exposed with the stripes in a second stripe-exposure sequence different from the first stripe-exposure sequence; and (c) if the magnitude of thermal expansion determined in step (b) is lower than the magnitude of thermal expansion determined in step (a), then exposing the chip region using the second stripe-exposure sequence.
Claim 3
Dependent Claim
49 words
The method of claim 1 , further comprising the steps: exposing the die pattern first to chip regions located fully on the sensitive surface; and after exposing the chip regions located fully on the sensitive surface, exposing the die pattern to chip regions extending partially off the sensitive surface.
Claim 4
Dependent Claim
43 words
The method of claim 1 , wherein: the chip regions on the sensitive surface are exposed individually in a chip-exposure sequence; and the chip-exposure sequence is opposite the second stripe-exposure sequence, so as to mutually cancel forces of thermal expansion of the substrate.
Claim 5
Dependent Claim
49 words
The method of claim 3 , further comprising the steps: exposing the die pattern first to chip regions located fully on the sensitive surface; and after exposing the chip regions located fully on the sensitive surface, exposing the die pattern to chip regions extending partially off the sensitive surface.
Claim 6
Dependent Claim
41 words
The method of claim 1 , wherein: the chip regions on the sensitive surface are exposed individually in a chip-exposure sequence in a fixed direction on the sensitive surface; and the stripe-exposure sequence has a direction identical to the fixed direction.
Claim 7
Dependent Claim
49 words
The method of claim 5 , further comprising the steps: exposing the die pattern first to chip regions located fully on the sensitive surface; and after exposing the chip regions located fully on the sensitive surface, exposing the die pattern to chip regions extending partially off the sensitive surface.
Claim 8
Dependent Claim
36 words
The method of claim 1 , wherein chip regions on the sensitive surface in which thermal expansion is determined to be greater are exposed before chip regions in which thermal expansion is determined to be less.
Claim 9
Dependent Claim
49 words
The method of claim 7 , further comprising the steps: exposing the die pattern first to chip regions located fully on the sensitive surface; and after exposing the chip regions located fully on the sensitive surface, exposing the die pattern to chip regions extending partially off the sensitive surface.
Claim 10
Dependent Claim
53 words
The method of claim 1 , further comprising: providing a wafer chuck comprising a wafer-mounting surface defining a channel for conducting a heat-transfer gas; mounting the substrate on the wafer chuck; and during exposure of the sensitive surface, passing the heat-transfer gas through the channel such that the heat-transfer gas contacts the substrate.
Claim 11
Dependent Claim
43 words
The method of claim 9 , further comprising: providing the wafer chuck with a conduit for conducting a liquid coolant; and during exposure of the sensitive surface, conducting the liquid coolant through the conduit to maintain the wafer chuck at a constant temperature.
Claim 12
Dependent Claim
49 words
The method of claim 9 , further comprising the steps: exposing the die pattern first to chip regions located fully on the sensitive surface; and after exposing the chip regions located fully on the sensitive surface, exposing the die pattern to chip regions extending partially off the sensitive surface.
Claim 13
Dependent Claim
58 words
The method of claim 1 , further comprising: predicting an amount of thermal expansion of the substrate expected to occur during exposure of the substrate; and during exposure, applying a positional correction of the exposure on the substrate so as to mutually cancel forces of thermal expansion of the substrate and offset the predicted amount of thermal expansion.
Claim 14
Dependent Claim
49 words
The method of claim 12 , further comprising the steps: exposing the die pattern first to chip regions located fully on the sensitive surface; and after exposing the chip regions located fully on the sensitive surface, exposing the die pattern to chip regions extending partially off the sensitive surface.
Claim 15
Dependent Claim
84 words
In a microlithography method in which a die pattern, defined on a segmented reticle, is projection-transferred using a charged particle beam to multiple chip regions arrayed on a sensitive surface of a substrate, a method for reducing thermal expansion of the substrate during exposure, comprising: exposing the die pattern first to chip regions located fully on the sensitive surface; and after exposing the chip regions located fully on the sensitive surface, exposing the die pattern to chip regions extending partially off the sensitive surface.
Claim 16
Dependent Claim
84 words
In a microlithography method in which a die pattern, defined on a segmented reticle, is projection-transferred using a charged particle beam to multiple chip regions arrayed on a sensitive surface of a substrate, a method for reducing thermal expansion of the substrate during exposure, comprising: exposing the die pattern first to chip regions located fully on the sensitive surface; and after exposing the chip regions located fully on the sensitive surface, exposing the die pattern to chip regions extending partially off the sensitive surface.
Claim 17
Independent Claim
190 words
A method for microlithographically transferring a die pattern, defined on a segmented reticle including multiple stripes defining respective portions of the pattern, stripe-by-stripe onto a chip region on a sensitive surface of a substrate using a charged particle beam, comprising: (a) illuminating a region in a stripe of the reticle pattern using a charged particle beam; (b) directing the charged particle beam passing through the illuminated region to a respective region on the sensitive surface so as to form an image of the illuminated region on the respective region on the sensitive surface; (c) determining a magnitude of thermal expansion of the substrate that would occur if a chip region on the substrate were exposed with the stripes in a first stripe-exposure sequence; (d) determining a magnitude of thermal expansion of the substrate that would occur if the chip region were exposed with the stripes in a second stripe-exposure sequence different from the first stripe-exposure sequence; and (e) if the magnitude of thermal expansion determined in step (d) is lower than the magnitude of thermal expansion determined in step (c), then exposing the chip region using the second stripe-exposure sequence.
Claim 18
Independent Claim
190 words
A method for microlithographically transferring a die pattern, defined on a segmented reticle including multiple stripes defining respective portions of the pattern, stripe-by-stripe onto a chip region on a sensitive surface of a substrate using a charged particle beam, comprising: (a) illuminating a region in a stripe of the reticle pattern using a charged particle beam; (b) directing the charged particle beam passing through the illuminated region to a respective region on the sensitive surface so as to form an image of the illuminated region on the respective region on the sensitive surface; (c) determining a magnitude of thermal expansion of the substrate that would occur if a chip region on the substrate were exposed with the stripes in a first stripe-exposure sequence; (d) determining a magnitude of thermal expansion of the substrate that would occur if the chip region were exposed with the stripes in a second stripe-exposure sequence different from the first stripe-exposure sequence; and (e) if the magnitude of thermal expansion determined in step (d) is lower than the magnitude of thermal expansion determined in step (c), then exposing the chip region using the second stripe-exposure sequence.
Claim 19
Independent Claim
134 words
A method for microlithographically transferring a die pattern, defined on a segmented reticle including multiple stripes defining respective portions of the pattern, stripe-by-stripe onto a chip region on a sensitive surface of a substrate using a charged particle beam, comprising: (a) illuminating a region in a stripe of the reticle pattern using a charged particle beam; (b) directing the charged particle beam passing through the illuminated region to a respective region on the sensitive surface so as to form an image of the illuminated region on the respective region on the sensitive surface; (c) exposing the die pattern first to chip regions located fully on the sensitive surface; and (d) after exposing the chip regions located fully on the sensitive surface, exposing the die pattern to chip regions extending partially off the sensitive surface.
Claim 20
Independent Claim
134 words
A method for microlithographically transferring a die pattern, defined on a segmented reticle including multiple stripes defining respective portions of the pattern, stripe-by-stripe onto a chip region on a sensitive surface of a substrate using a charged particle beam, comprising: (a) illuminating a region in a stripe of the reticle pattern using a charged particle beam; (b) directing the charged particle beam passing through the illuminated region to a respective region on the sensitive surface so as to form an image of the illuminated region on the respective region on the sensitive surface; (c) exposing the die pattern first to chip regions located fully on the sensitive surface; and (d) after exposing the chip regions located fully on the sensitive surface, exposing the die pattern to chip regions extending partially off the sensitive surface.
Claim 21
Dependent Claim
69 words
A microelectronic-device fabrication process, comprising the steps of: (a) preparing a wafer; (b) processing the wafer; and (c) assembling devices formed on the wafer during steps (a) and (b), wherein step (b) comprises the steps of (i) applying resist to the wafer; (ii) exposing the resist; and (iii) developing the resist; and step (ii) comprises the method for microlithographically transferring a die pattern as recited in claim 15 .
Claim 22
Dependent Claim
69 words
A microelectronic-device fabrication process, comprising the steps of: (a) preparing a wafer; (b) processing the wafer; and (c) assembling devices formed on the wafer during steps (a) and (b), wherein step (b) comprises the steps of (i) applying resist to the wafer; (ii) exposing the resist; and (iii) developing the resist; and step (ii) comprises the method for microlithographically transferring a die pattern as recited in claim 16 .
Claim 23
Dependent Claim
11 words
A microelectronic device produced by the method of claim 17 .
Claim 24
Dependent Claim
11 words
A microelectronic device produced by the method of claim 18 .
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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) | 2005-09-09 | 2006-03-11 | 2006-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-09-09 | 2010-03-11 | 2010-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-09-09 | 2014-03-11 | 2014-09-10 | $7700.00 | Window Closed / Lapsed |