US5208629A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical projection exposure method and system using the same
Assignee: NTT Inc
•
Filing: 1992-04-03
•
Granted: 1993-05-04
•
Expires: 2012-04-03
Abstract
Abstract According to this invention, illumination light for illuminating a mask on which a micropattern is drawn is inclined at an angle corresponding to a numerical aperture of an optical projection lens located below the mask with respect to an optical axis. The illumination light is obliquely incident on the mask to expose the micropattern on an object located below the optical projection lens.
Inventors
- 👤 Seitaro Matsuo
- 👤 Yoshinobu Takeuchi
- 👤 Kazuhiko Komatsu
- 👤 Emi Tamechika
- 👤 Katsuhiro Harada
- 👤 Yoshiaki Mimura
- 👤 Toshiyuki Horiuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:25
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70058; G03F7/70125; G03F7/70091; G03F7/70216; G03F7/70241; G03F7/7025; G03F7/70308; G03F7/70483; G03F7/70491; G03F7/705
Claims Analysis
Total Claims: 93
Claim 1
Independent Claim
71 words
An optical projection exposure method of a micropattern, comprising the steps of inclining illumination light for illuminating a mask having the micropattern thereon by an angle corresponding to a numerical aperture of an optical projection lens located below said mask with respect to an optical axis, and causing the illumination light to be obliquely incident on said mask to expose the micropattern on an object located below said optical projection lens.
Claim 2
Dependent Claim
71 words
An optical projection exposure method of a micropattern, comprising the steps of inclining illumination light for illuminating a mask having the micropattern thereon by an angle corresponding to a numerical aperture of an optical projection lens located below said mask with respect to an optical axis, and causing the illumination light to be obliquely incident on said mask to expose the micropattern on an object located below said optical projection lens.
Claim 3
Dependent Claim
22 words
A method according to claim 1, wherein the illumination light is obtained by superposing a plurality of rays incoherent to each other.
Claim 4
Dependent Claim
33 words
A method according to claim 1, wherein the illumination light is constituted by rays obliquely incident from two directions at equal angular intervals when viewed on a plane perpendicular to the optical axis.
Claim 5
Dependent Claim
33 words
A method according to claim 1, wherein the illumination light is constituted by rays obliquely incident from four directions at equal angular intervals when viewed on a plane perpendicular to the optical axis.
Claim 6
Dependent Claim
43 words
A method according to claim 2, wherein the rays constituting the illumination light are obliquely incident in axial symmetry with respect to the optical axis at angles corresponding to the numerical aperture of said optical projection lens with respect to the optical axis.
Claim 7
Dependent Claim
14 words
A method according to claim 1, wherein the illumination light has an annular shape.
Claim 8
Dependent Claim
42 words
A method according to claim 1, wherein said optical projection lens has an optical projection lens aperture whose transmittance is adjusted at least at a portion having a shape corresponding to a light source image (without a reticle) focused at the aperture.
Claim 9
Dependent Claim
29 words
A method according to claim 1, wherein said optical projection lens comprises first and second lens systems and an aperture stop located between said first and second lens systems.
Claim 10
Dependent Claim
30 words
A method according to claim 1, wherein the illumination light obliquely incident on said mask is formed by an optical device located on a light source side of said mask.
Claim 11
Dependent Claim
17 words
A method according to claim 9, wherein said optical device comprises a device having a periodic structure.
Claim 12
Dependent Claim
13 words
A method according to claim 9, wherein said optical device is a prism.
Claim 13
Dependent Claim
23 words
A method according to claim 9, wherein said optical device comprises a combination of a device having a periodic structure and a prism.
Claim 14
Dependent Claim
24 words
A method according to claim 9, wherein said optical device comprises a device having periodic patterns respectively formed on both surfaces of a substrate.
Claim 15
Dependent Claim
16 words
A method according to claim 9, wherein said optical device is formed integrally with said mask.
Claim 16
Dependent Claim
60 words
A method according to claim 14, wherein said mask has an opaque region and a transparent region, said opaque region being semi-transparent, having a transmittance set on the basis of a pattern shape, and having a structure such that light passing through said opaque region has a phase difference of a half wavelength from light passing through said transparent region.
Claim 17
Dependent Claim
19 words
A method according to claim 9, wherein said optical device is rotated about an axis perpendicular to said mask.
Claim 18
Dependent Claim
44 words
A method according to claim 6, wherein the annular illumination light is formed such that light from a light source is incident on a small-diameter incident surface obtained by bundling optical fibers in a doughnut-like shape and emerges from a large-diameter exit surface thereof.
Claim 19
Dependent Claim
43 words
A method according to claim 6, wherein the illumination light is obtained such that light from a light source is guided to a secondary source through a first optical system and light from said secondary source is transmitted through a second optical system.
Claim 20
Dependent Claim
15 words
A method according to claim 18, wherein said secondary source is an annular light source.
Claim 21
Dependent Claim
19 words
A method according to claim 18, wherein said second optical system includes a convex lens and a concave lens.
Claim 22
Dependent Claim
15 words
A method according to claim 20, wherein said second optical system includes a condenser lens.
Claim 23
Dependent Claim
37 words
A method according to claim 6, wherein the annular illumination light is formed such that light from a light source is incident on an incident surface of a conical lens and emerges from an exit surface thereof.
Claim 24
Dependent Claim
70 words
A method according to claim 1, wherein the step of causing the illumination light to be obliquely incident on said mask comprises the steps of causing light from a light source to be incident on an incident surface obtained by bundling optical fibers in a doughnut-like shape and causing the illumination light emerging from an exit surface thereof to be obliquely incident on said mask from at least one direction.
Claim 25
Dependent Claim
24 words
A method according to claim 23, wherein said incident surface of said optical fibers has a diameter larger than that of said exit surface.
Claim 26
Dependent Claim
44 words
A method according to claim 23, wherein the illumination light is obtained such that light from a light source is guided to a secondary source through a first optical system and light emerging from said secondary source is transmitted through a second optical system.
Claim 27
Dependent Claim
15 words
A method according to claim 18, wherein said secondary source is an annular light source.
Claim 28
Dependent Claim
19 words
A method according to claim 18, wherein said second optical system includes a convex lens and a concave lens.
Claim 29
Dependent Claim
37 words
A method according to claim 6, wherein the annular illumination light is formed such that light from a light source is incident on an incident surface of a conical lens and emerges from an exit surface thereof.
Claim 30
Dependent Claim
32 words
A method according to claim 1, wherein the illumination light incident on said mask is variably inclined within a range of angles corresponding to the numerical aperture of said optical projection lens.
Claim 31
Dependent Claim
31 words
A method according to claim 29, wherein the angle of the illumination light incident on said mask is changed in accordance with a parameter derived from the pattern on said mask.
Claim 32
Dependent Claim
27 words
A method according to claim 30, wherein the parameter includes at least one factor selected from the group consisting of the pattern shape and a pattern size.
Claim 33
Dependent Claim
24 words
A method according to claim 1, wherein coherency of said mask illumination light is adjusted by changing an effective area of the light source.
Claim 34
Dependent Claim
26 words
A method according to claim 32, wherein coherency of the illumination light is changed in accordance with a parameter derived from the pattern on said mask.
Claim 35
Dependent Claim
27 words
A method according to claim 33, wherein the parameter includes at least one factor selected from the group consisting of the pattern shape and a pattern size.
Claim 36
Dependent Claim
29 words
A method according to claim 1, wherein the illumination light is obliquely incident on said mask through at least one diaphragm located at a position outside the optical axis.
Claim 37
Dependent Claim
26 words
A method according to claim 35, wherein said diaphragm comprises two apertures having the same shape and centers corresponding to points symmetrical about the optical axis.
Claim 38
Dependent Claim
16 words
A method according to claim 35, wherein said diaphragm is located immediately behind said secondary source.
Claim 39
Dependent Claim
70 words
A method according to claim 1, wherein a filter designed such that a peripheral portion of an aperture corresponding to an image of a light source of an illumination system has an amplitude transmittance of 0.2 to 0.6 and a central portion of the aperture has an amplitude transmittance of 1 is arranged at an aperture stop of a projection optical system on which the illumination light is obliquely incident.
Claim 40
Dependent Claim
58 words
A method according to claim 38, wherein said illumination system and said filter are arranged such that the entire image of said light source which is focused at said aperture stop corresponds to an area in which said peripheral portion of said filter arranged at the position of said aperture stop has a transmittance of 0.2 to 0.6.
Claim 41
Dependent Claim
106 words
A method according to claim 1, wherein when a radius of an entrance pupil is normalized with the numerical aperture of said optical projection lens and is defined as 1, rays focused at an aperture stop of a projection optical system on which the illumination light is obliquely incident constitute an annular light source having inner and outer radii, and a zero-order light intensity adjustment filter having the same inner radius as that of the image of the rays focused at said aperture stop of said projection optical system and an outer radius of 1 is arranged at said aperture stop of said optical projection lens.
Claim 42
Dependent Claim
45 words
A method according to claim 40, wherein when the inner and outer radii of said annular light source are defined as R 1 and R 2 , respectively, the inner radius satisfies condition R 1 >0.5, and the outer radius satisfies conditions R 2 ≦1.
Claim 43
Dependent Claim
21 words
A method according to claim 40, wherein said zero-order light intensity adjustment filter has an amplitude transmittance T satisfying condition 0.2<T<1.
Claim 44
Dependent Claim
70 words
A method according to claim 40, wherein when the inner and outer radii of said annular light source are defined as R 1 and R 2 , respectively, a portion from the inner radius R to the outer radius R 2 of said zero-order light intensity adjustment filter has an amplitude transmittance different from that of a portion from the inner radius R 2 to the outer diameter of 1.
Claim 45
Dependent Claim
38 words
A method according to claim 1, wherein the illumination light is constituted by rays from four partially annular light sources from four directions symmetrical about the optical axis when viewed on a plane perpendicular to the optical axis.
Claim 46
Dependent Claim
74 words
A method according to claim 1, wherein said mask comprises a mask substrate having an opaque region having a predetermined pattern on one surface of said mask substrate, said opaque region being semi-transparent, having a transmittance set on the basis of a pattern shape, and having a structure such that light passing through said opaque region has a phase difference of a half wavelength from light passing through a transparent region of said mask.
Claim 47
Dependent Claim
84 words
An optical projection exposure apparatus of a micropattern, comprising: a light source; a mask on which the micropattern is drawn; an optical projection lens located below said mask; and means for obliquely illuminating the micropattern on said mask with illumination light inclined at an angle corresponding to a numerical aperture of said optical projection lens with respect to an optical axis, wherein the illumination light is obliquely incident on said mask to expose the micropattern on an object located below said optical projection lens.
Claim 48
Dependent Claim
84 words
An optical projection exposure apparatus of a micropattern, comprising: a light source; a mask on which the micropattern is drawn; an optical projection lens located below said mask; and means for obliquely illuminating the micropattern on said mask with illumination light inclined at an angle corresponding to a numerical aperture of said optical projection lens with respect to an optical axis, wherein the illumination light is obliquely incident on said mask to expose the micropattern on an object located below said optical projection lens.
Claim 49
Dependent Claim
22 words
An apparatus according to claim 46, wherein the illumination light is obtained by superposing a plurality of rays incoherent to each other.
Claim 50
Dependent Claim
33 words
An apparatus according to claim 46, wherein the illumination light is constituted by rays obliquely incident from two directions at equal angular intervals when viewed on a plane perpendicular to the optical axis.
Claim 51
Dependent Claim
33 words
An apparatus according to claim 46, wherein the illumination light is constituted by rays obliquely incident from four directions at equal angular intervals when viewed on a plane perpendicular to the optical axis.
Claim 52
Dependent Claim
43 words
An apparatus according to claim 47, wherein the rays constituting the illumination light are obliquely incident in axial symmetry with respect to the optical axis at angles corresponding to the numerical aperture of said optical projection lens with respect to the optical axis.
Claim 53
Dependent Claim
14 words
An apparatus according to claim 46, wherein the illumination light has an annular shape.
Claim 54
Dependent Claim
42 words
An apparatus according to claim 46, wherein said optical projection lens has an optical projection lens aperture whose transmittance is adjusted at least at a portion having a shape corresponding to a light source image (without a reticle) focused at the aperture.
Claim 55
Dependent Claim
29 words
An apparatus according to claim 46, wherein said optical projection lens comprises first and second lens systems and an aperture stop located between said first and second lens systems.
Claim 56
Dependent Claim
30 words
An apparatus according to claim 46, wherein said means for obliquely illuminating the micropattern on said mask comprises an optical device located on a light source side of said mask.
Claim 57
Dependent Claim
17 words
An apparatus according to claim 54, wherein said optical device comprises a device having a periodic structure.
Claim 58
Dependent Claim
13 words
An apparatus according to claim 54, wherein said optical device is a prism.
Claim 59
Dependent Claim
23 words
An apparatus according to claim 54, wherein said optical device comprises a combination of a device having a periodic structure and a prism.
Claim 60
Dependent Claim
24 words
An apparatus according to claim 54, wherein said optical device comprises a device having periodic patterns respectively formed on both surfaces of a substrate.
Claim 61
Dependent Claim
34 words
An apparatus according to claim 54, further comprising an optical device attaching/detaching mechanism for holding said optical device on a light source side of said mask and attaching/detaching said optical mask to/from said mask.
Claim 62
Dependent Claim
16 words
An apparatus according to claim 54, wherein said optical device is formed integrally with said mask.
Claim 63
Dependent Claim
60 words
An apparatus according to claim 60, wherein said mask has an opaque region and a transparent region, said opaque region being semi-transparent, having a transmittance set on the basis of a pattern shape, and having a structure such that light passing through said opaque region has a phase difference of a half wavelength from light passing through said transparent region.
Claim 64
Dependent Claim
19 words
An apparatus according to claim 54, wherein said optical device is rotated about an axis perpendicular to said mask.
Claim 65
Dependent Claim
72 words
An apparatus according to claim 46, wherein said means for obliquely illuminating the micropattern on said mask comprises a bundle of optical fibers bundled in a doughnut-like shape and having a small-diameter incident surface and a large-diameter exit surface, so that light from said light source is incident on said small-diameter incident surface of said bundle of optical fibers and emerges from said large-diameter exit surface thereof to form the illumination light.
Claim 66
Dependent Claim
53 words
An apparatus according to claim 51, wherein said means for obliquely illuminating the micropattern on said mask comprises means for guiding light from a light source to a secondary source through a first optical system, and means for transmitting light from said secondary source through a second optical system as the illumination light.
Claim 67
Dependent Claim
15 words
An apparatus according to claim 64, wherein said secondary source is an annular light source.
Claim 68
Dependent Claim
19 words
An apparatus according to claim 64, wherein said second optical system includes a convex lens and a concave lens.
Claim 69
Dependent Claim
16 words
An apparatus according to claim 66, wherein said second optical system further includes a condenser lens.
Claim 70
Dependent Claim
43 words
An apparatus according to claim 51, wherein said means for obliquely illuminating the micropattern on said mask comprises a conical lens having an incident surface for receiving light from a light source and an exit surface for causing the illumination light to emerge.
Claim 71
Dependent Claim
61 words
An apparatus according to claim 51, wherein said means for obliquely illuminating the micropattern on said mask comprises optical fibers having an incident surface for receiving light from said light source and an exit surface for causing the illumination light to emerge, the illumination light emerging from said exit surface being obliquely incident on said mask from at least one direction.
Claim 72
Dependent Claim
24 words
An apparatus according to claim 69, wherein said incident surface of said optical fibers has a diameter larger than that of said exit surface.
Claim 73
Dependent Claim
44 words
An apparatus according to claim 69, wherein the illumination light is obtained such that light from a light source is guided to a secondary source through a first optical system and light emerging from said secondary source is transmitted through a second optical system.
Claim 74
Dependent Claim
15 words
An apparatus according to claim 71, wherein said secondary source is an annular light source.
Claim 75
Dependent Claim
19 words
An apparatus according to claim 71, wherein said second optical system includes a convex lens and a concave lens.
Claim 76
Dependent Claim
43 words
An apparatus according to claim 69, wherein said means for obliquely illuminating the micropattern on said mask comprises a conical lens having an incident surface for receiving light from a light source and an exit surface for causing the illumination light to emerge.
Claim 77
Dependent Claim
44 words
An apparatus according to claim 46, wherein said means for obliquely illuminating the micropattern on said mask comprises means for variably inclining the illumination light incident on said mask within a range of angles corresponding to the numerical aperture of said optical projection lens.
Claim 78
Dependent Claim
38 words
An apparatus according to claim 75, wherein said means for variably inclining the illumination light changes the angle of the illumination light incident on said mask in accordance with a parameter derived from the pattern on said mask.
Claim 79
Dependent Claim
27 words
An apparatus according to claim 76, wherein the parameter includes at least one factor selected from the group consisting of the pattern shape and a pattern size.
Claim 80
Dependent Claim
37 words
An apparatus according to claim 46, wherein said means for obliquely illuminating the micropattern on said mask further comprises means for adjusting coherency of said mask illumination light by changing an effective area of the light source.
Claim 81
Dependent Claim
34 words
An apparatus according to claim 78, wherein said means for adjusting coherency of the illumination light changes coherency of the illumination light in accordance with a parameter derived from the pattern on said mask.
Claim 82
Dependent Claim
27 words
An apparatus according to claim 79, wherein the parameter includes at least one factor selected from the group consisting of the pattern shape and a pattern size.
Claim 83
Dependent Claim
44 words
An apparatus according to claim 46, wherein said means for obliquely illuminating the micropattern on said mask comprises at least one diaphragm located at a position outside the optical axis, so that the illumination light is obliquely incident on said mask through said diaphragm.
Claim 84
Dependent Claim
26 words
An apparatus according to claim 81, wherein said diaphragm comprises two apertures having the same shape and centers corresponding to points symmetrical about the optical axis.
Claim 85
Dependent Claim
16 words
An apparatus according to claim 81, wherein said diaphragm is located immediately behind said secondary source.
Claim 86
Dependent Claim
84 words
An apparatus according to claim 46, wherein said means for obliquely illuminating the micropattern on said mask is arranged such that a filter designed such that a peripheral portion of an aperture corresponding to an image of a light source of an illumination system has an amplitude transmittance of 0.2 to 0.6 and a central portion of the aperture has an amplitude transmittance of 1 is arranged at an aperture stop of a projection optical system on which the illumination light is obliquely incident.
Claim 87
Dependent Claim
58 words
An apparatus according to claim 84, wherein said illumination system and said filter are arranged such that the entire image of said light source which is focused at said aperture stop corresponds to an area in which said peripheral portion of said filter arranged at the position of said aperture stop has a transmittance of 0.2 to 0.6.
Claim 88
Dependent Claim
124 words
An apparatus according to claim 46, wherein when a radius of an entrance pupil is normalized with the numerical aperture of said optical projection lens and is defined as 1, said light source whose rays focused at an aperture stop of a projection optical system on which the illumination light is obliquely incident is an annular light source having inner and outer radii, and said means for obliquely illuminating the micropattern on said mask is arranged such that a zero-order light intensity adjustment filter having the same inner radius as that of the image of the rays focused at said aperture stop of said projection optical system and an outer radius of 1 is arranged at said aperture stop of said optical projection lens.
Claim 89
Dependent Claim
45 words
An apparatus according to claim 86, wherein when the inner and outer radii of said annular light source are defined as R 1 and R 2 , respectively, the inner radius satisfies condition R 1 >0.5, and the outer radius satisfies condition R 2 ≦1.
Claim 90
Dependent Claim
22 words
An apparatus according to claim 86, wherein said zero-order light intensity adjustment filter has an amplitude transmittance T satisfying condition 0.2<T 1.
Claim 91
Dependent Claim
71 words
An apparatus according to claim 86, wherein when the inner and outer radii of said annular light source are defined as R 1 and R 2 , respectively, a portion from the inner radius R 1 to the outer radius R 2 of said zero-order light intensity adjustment filter has an amplitude transmittance different from that of a portion from the inner radius R 2 to the outer diameter of 1.
Claim 92
Dependent Claim
45 words
An apparatus according to claim 46, wherein said light source is arranged such that the illumination light is constituted by rays from four partially annular light sources from four directions symmetrical about the optical axis when viewed on a plane perpendicular to the optical axis.
Claim 93
Dependent Claim
74 words
An apparatus according to claim 46, wherein said mask comprises a mask substrate having an opaque region having a predetermined pattern on one surface of said mask substrate, said opaque region being semi-transparent, having a transmittance set on the basis of a pattern shape, and having a structure such that light passing through said opaque region has a phase difference of a half wavelength from light passing through a transparent region of said mask.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-05-03 | 1996-11-02 | 1997-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-05-03 | 2000-11-02 | 2001-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-05-03 | 2004-11-02 | 2005-05-04 | $7700.00 | Window Closed / Lapsed |