US5248575A
Expired / Lapsed
US
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Photomask with phase shifter and method of fabricating semiconductor device by using the same
Assignee: Seiko Epson Corp
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Filing: 1991-10-09
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Granted: 1993-09-28
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Expires: 2011-10-09
Abstract
Abstract A photomask has a light shielding layer and a phase shifter based on a phase shift method, both of which are mounted on a mask substrate. The light shielding layer is shaped in a light shielding pattern, having light passing regions beside its opposite sides. The phase shifter is made by thinning the mask substrate at a portion associated with one of the light passing regions. An optical path through the phase shifter is shorter than the optical path of the other light passing region, thereby shifting the phase of light.
Inventors
- 👤 Ken Ogoshi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:24
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/26; G03F1/30; G03F1/50
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
186 words
A photomask with a phase shifter, comprising: (a) a mask substrate made of material passing exposing light; (b) a light shielding layer made of material shielding the exposing light, said light shielding layer being in the shape of light shielding patterns on the said mask substrate; (c) light passing regions positioned beside each of said light shielding patterns on said mask substrate (d) a phase shifter positioned at a small thickness portion of said mask substrate and associated with one of said light passing regions, said phase shifter shifting the phase of the exposing light by differentiating lengths of optical paths through said light passing regions, wherein said phase shifter is a recess on said mask substrate on a surface opposite to the surface where said light shielding layer is positioned, being associated with one of said light passing regions, and wherein a depth D of said phase shifter is given by D=(100±5.56%×λ/[2×(n.sub.1 -n.sub.2)] where λ is a wavelength of the exposing light, n 1 is a refractive index of said mask substrate, and n 2 is a refractive index of an ambience around said photomask.
Claim 2
Dependent Claim
186 words
A photomask with a phase shifter, comprising: (a) a mask substrate made of material passing exposing light; (b) a light shielding layer made of material shielding the exposing light, said light shielding layer being in the shape of light shielding patterns on the said mask substrate; (c) light passing regions positioned beside each of said light shielding patterns on said mask substrate (d) a phase shifter positioned at a small thickness portion of said mask substrate and associated with one of said light passing regions, said phase shifter shifting the phase of the exposing light by differentiating lengths of optical paths through said light passing regions, wherein said phase shifter is a recess on said mask substrate on a surface opposite to the surface where said light shielding layer is positioned, being associated with one of said light passing regions, and wherein a depth D of said phase shifter is given by D=(100±5.56%×λ/[2×(n.sub.1 -n.sub.2)] where λ is a wavelength of the exposing light, n 1 is a refractive index of said mask substrate, and n 2 is a refractive index of an ambience around said photomask.
Claim 3
Dependent Claim
17 words
A photomask according to claim 1, wherein the exposing light is an i-ray of a mercury lamp.
Claim 4
Dependent Claim
91 words
A photomask with a phase shifter, comprising: (a) a mask substrate made of material passing exposing light; and (b) a phase shifter positioned at a small thickness portion of said mask substrate and having an optical path shorter than the remaining portion of said mask substrate to shift the phase of the exposing light; and whereby intensity of the exposing light passing through a border between said phase shifter and the remaining portion of said substrate is decreased to form an exposed pattern without the use of a light shielding layer.
Claim 5
Dependent Claim
91 words
A photomask with a phase shifter, comprising: (a) a mask substrate made of material passing exposing light; and (b) a phase shifter positioned at a small thickness portion of said mask substrate and having an optical path shorter than the remaining portion of said mask substrate to shift the phase of the exposing light; and whereby intensity of the exposing light passing through a border between said phase shifter and the remaining portion of said substrate is decreased to form an exposed pattern without the use of a light shielding layer.
Claim 6
Dependent Claim
69 words
A photomask according to claim 3, wherein said phase shifter is a recess in the shape of a pattern on said mask substrate, and wherein a depth D of said phase shifter is given by D=(100±5.56%×λ/[2×(n.sub.1 -n.sub.2)] where λ is a wavelength of the exposing light, n 1 is a refractive index of said mask substrate, and n 2 is a refractive index of an ambience around said photomask.
Claim 7
Dependent Claim
17 words
A photomask according to claim 4, wherein the exposing light is an i-ray of a mercury lamp.
Claim 8
Dependent Claim
200 words
A photomask with edge-emphasized phase shifters, comprising: (a) a mask substrate made of material passing exposing light; (b) a light shielding layer made of material shielding the exposing light, said light shielding layer being in the shape of light shielding patterns on said mask substrate; (c) light passing regions positioned beside said light shielding patterns on said mask substrate; (d) a plurality of phase shifters positioned at small thickness portions of said mask substrate and at positions associated with opposite edges of each said light passing region to differentiate length of an optical path through the central portions of said light passing regions and to shift the phase of light at said edges of each said light passing region; and wherein said phase shifter is a recess on said mask substrate on a surface opposite to the surface where said light shielding layer is mounted, being associated with one of said light passing regions, and wherein a depth D of said phase shifter is given by D=(100±5.56%×λ/[2×(n.sub.1 -n.sub.2)] where λ is a wavelength of the exposing light, n 1 is a refractive index of said mask substrate, and n 2 is a refractive index of an ambience around said photomask.
Claim 9
Dependent Claim
200 words
A photomask with edge-emphasized phase shifters, comprising: (a) a mask substrate made of material passing exposing light; (b) a light shielding layer made of material shielding the exposing light, said light shielding layer being in the shape of light shielding patterns on said mask substrate; (c) light passing regions positioned beside said light shielding patterns on said mask substrate; (d) a plurality of phase shifters positioned at small thickness portions of said mask substrate and at positions associated with opposite edges of each said light passing region to differentiate length of an optical path through the central portions of said light passing regions and to shift the phase of light at said edges of each said light passing region; and wherein said phase shifter is a recess on said mask substrate on a surface opposite to the surface where said light shielding layer is mounted, being associated with one of said light passing regions, and wherein a depth D of said phase shifter is given by D=(100±5.56%×λ/[2×(n.sub.1 -n.sub.2)] where λ is a wavelength of the exposing light, n 1 is a refractive index of said mask substrate, and n 2 is a refractive index of an ambience around said photomask.
Claim 10
Dependent Claim
217 words
A photomask with auxiliary shifters, comprising: (a) a mask substrate made of material passing exposing light; (b) a light shielding layer made of material shielding the exposing light, said light shielding layer being in the shape of light shielding patterns on said mask substrate; (c) main light passing regions located outside opposite side edges of said light shielding patterns on said mask substrate; (d) auxiliary light passing regions located inside opposite side edges of each said light shielding patterns; (e) a plurality of phase shifters, each of said phase shifters being located at a small thickness portion of said mask substrate associated with each said auxiliary light passing regions so that a phase of light at said auxiliary light passing regions is shifted due to difference of optical path length through each of said phase shifters; and wherein said phase shifter is a recess on said mask substrate on a surface opposite to the surface where said light shielding layer is mounted, being associated with one of said light passing regions, and wherein a depth D of said phase shifter is given by D=(100±5.56%×λ/[2×(n.sub.1 -n.sub.2)] where λ is a wavelength of the exposing light, n 1 is a refractive index of said mask substrate, and n 2 is a refractive index of an ambience around said photomask.
Claim 11
Dependent Claim
217 words
A photomask with auxiliary shifters, comprising: (a) a mask substrate made of material passing exposing light; (b) a light shielding layer made of material shielding the exposing light, said light shielding layer being in the shape of light shielding patterns on said mask substrate; (c) main light passing regions located outside opposite side edges of said light shielding patterns on said mask substrate; (d) auxiliary light passing regions located inside opposite side edges of each said light shielding patterns; (e) a plurality of phase shifters, each of said phase shifters being located at a small thickness portion of said mask substrate associated with each said auxiliary light passing regions so that a phase of light at said auxiliary light passing regions is shifted due to difference of optical path length through each of said phase shifters; and wherein said phase shifter is a recess on said mask substrate on a surface opposite to the surface where said light shielding layer is mounted, being associated with one of said light passing regions, and wherein a depth D of said phase shifter is given by D=(100±5.56%×λ/[2×(n.sub.1 -n.sub.2)] where λ is a wavelength of the exposing light, n 1 is a refractive index of said mask substrate, and n 2 is a refractive index of an ambience around said photomask.
Claim 12
Independent Claim
150 words
A method of fabricating a semiconductor device, comprising the steps of: providing a photomask comprising a mask substrate made of material passing exposing light, a light shielding layer made of material shielding the exposing light, said light shielding layer being in the shape of a light shielding pattern on said mask substrate, light passing regions positioned beside said light shielding pattern on said mask substrate, a phase shifter positioned at a small thickness portion of said mask substrate associated with one of said light passing regions, said phase shifter shifting the phase of the exposing light by differentiating lengths of optical paths through said light passing regions, wherein said phase shifter is a recess on said mask substrate on a surface opposite to the surface where said light shielding layer is mounted; and exposing light to a resist coated on an etched layer of a semiconductor substrate through the photomask.
Claim 13
Independent Claim
150 words
A method of fabricating a semiconductor device, comprising the steps of: providing a photomask comprising a mask substrate made of material passing exposing light, a light shielding layer made of material shielding the exposing light, said light shielding layer being in the shape of a light shielding pattern on said mask substrate, light passing regions positioned beside said light shielding pattern on said mask substrate, a phase shifter positioned at a small thickness portion of said mask substrate associated with one of said light passing regions, said phase shifter shifting the phase of the exposing light by differentiating lengths of optical paths through said light passing regions, wherein said phase shifter is a recess on said mask substrate on a surface opposite to the surface where said light shielding layer is mounted; and exposing light to a resist coated on an etched layer of a semiconductor substrate through the photomask.
Claim 14
Dependent Claim
17 words
A method according to claim 8, wherein the exposing light is an i-ray of a mercury lamp.
Claim 15
Independent Claim
113 words
A method of fabricating a semiconductor device, comprising the steps of: providing a photomask comprising a mask substrate made of material passing exposing light, a phase shifter positioned at a small thickness portion of said mask substrate and having an optical path shorter than the remaining portion of said mask substrate to shift the phase of the exposing light, and whereby intensity of light passing through a border between said phase shifter and the remaining portion of said substrate is decreased to form an exposed pattern without the use of a light shielding layer; and applying exposing light to a resist coated on an etched layer of a semiconductor substrate through the photomask.
Claim 16
Independent Claim
113 words
A method of fabricating a semiconductor device, comprising the steps of: providing a photomask comprising a mask substrate made of material passing exposing light, a phase shifter positioned at a small thickness portion of said mask substrate and having an optical path shorter than the remaining portion of said mask substrate to shift the phase of the exposing light, and whereby intensity of light passing through a border between said phase shifter and the remaining portion of said substrate is decreased to form an exposed pattern without the use of a light shielding layer; and applying exposing light to a resist coated on an etched layer of a semiconductor substrate through the photomask.
Claim 17
Dependent Claim
17 words
A method according to claim 10, wherein the exposing light is an i-ray of a mercury lamp.
Claim 18
Independent Claim
171 words
A method of fabricating a semiconductor device, comprising the steps of: providing a photomask comprising a mask substrate made of material passing exposing light, a light shielding layer made of material shielding the exposing light, said light shielding layer being in the shape of a light shielding pattern on said mask substrate, light passing regions positioned beside said light shielding pattern on said mask substrate, a plurality of edge-emphasized phase shifters positioned at small thickness portions of said mask substrate and at positions associated with opposite edges of each of said light passing regions to differentiate length of an optical path through the central portions of said light passing regions and to shift the phase of light at said edges of each of said light passing regions, wherein said phase shifter is a recess on said mask substrate on a surface opposite to the surface where said light shielding layer is mounted; and applying exposing light to a resist coated on an etched portion of a semiconductor substrate through the photomask.
Claim 19
Independent Claim
171 words
A method of fabricating a semiconductor device, comprising the steps of: providing a photomask comprising a mask substrate made of material passing exposing light, a light shielding layer made of material shielding the exposing light, said light shielding layer being in the shape of a light shielding pattern on said mask substrate, light passing regions positioned beside said light shielding pattern on said mask substrate, a plurality of edge-emphasized phase shifters positioned at small thickness portions of said mask substrate and at positions associated with opposite edges of each of said light passing regions to differentiate length of an optical path through the central portions of said light passing regions and to shift the phase of light at said edges of each of said light passing regions, wherein said phase shifter is a recess on said mask substrate on a surface opposite to the surface where said light shielding layer is mounted; and applying exposing light to a resist coated on an etched portion of a semiconductor substrate through the photomask.
Claim 20
Independent Claim
189 words
A method of fabricating a semiconductor device, comprising the steps of: providing a photomask comprising a mask substrate made of material passing exposing light, a light shielding layer made of material shielding the exposing light, said light shielding layer being in the shape of light shielding pattern on said mask substrate, main light passing regions located outside opposite side edges of said light shielding pattern on said mask substrate auxiliary light passing regions located inside opposite side edges of said light shielding pattern, a plurality of phase shifters, each of said phase shifters being located at a small thickness portion of said mask substrate associated with each of said auxiliary light passing regions so that phase of light at said auxiliary light passing regions is shifted due to difference of optical path length through each of said phase shifters, a plurality of auxiliary phase shifters, wherein said phase shifter is a recess on said mask substrate on a surface opposite to the surface where said light shielding layer is mounted; and applying exposing light to a resist coated on an etched layer of a semiconductor substrate through the photomask.
Claim 21
Independent Claim
189 words
A method of fabricating a semiconductor device, comprising the steps of: providing a photomask comprising a mask substrate made of material passing exposing light, a light shielding layer made of material shielding the exposing light, said light shielding layer being in the shape of light shielding pattern on said mask substrate, main light passing regions located outside opposite side edges of said light shielding pattern on said mask substrate auxiliary light passing regions located inside opposite side edges of said light shielding pattern, a plurality of phase shifters, each of said phase shifters being located at a small thickness portion of said mask substrate associated with each of said auxiliary light passing regions so that phase of light at said auxiliary light passing regions is shifted due to difference of optical path length through each of said phase shifters, a plurality of auxiliary phase shifters, wherein said phase shifter is a recess on said mask substrate on a surface opposite to the surface where said light shielding layer is mounted; and applying exposing light to a resist coated on an etched layer of a semiconductor substrate through the photomask.
References Cited (Backward Citations)
US5045417A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-09-27 | 1997-03-29 | 1997-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-27 | 2001-03-29 | 2001-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-27 | 2005-03-29 | 2005-09-28 | $7700.00 | Window Closed / Lapsed |