US5815247A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Avoidance of pattern shortening by using off axis illumination with dipole and polarizing apertures
Assignee: Toshiba Corp
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Filing: 1995-09-21
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Granted: 1998-09-29
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Expires: 2015-09-21
Abstract
Abstract A system and method of avoiding pattern shortening without resorting to generating a mask with a bias solve the direction dependent differences in exposure behavior in photolithography processes in the manufacture of semiconductor devices. Instead of designing a biased mask to solve the exposure problem, the pattern shortening effect is avoided by influencing the exposure process itself. By using an off axis illumination technique, the exposure is separated into different directions. In one embodiment, off axis illumination is applied in combination with special dipole apertures (i.e., two openings). The exposure is done in two or more parts, whereby the aperture is twisted between exposures. In another embodiment, off axis illumination is used in combination with special polarizer apertures. As with the first embodiment, the exposure is done in two or more parts, but in this case with differently polarized light.
Inventors
- 👤 Bernhard Poschenrieder
- 👤 Takashi Sato
- 👤 Tsukasa Azuma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:04
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/20; G03F7/70; G03F7/70483; G03F7/7055; G03F7/70558; G03F7/2022; G03F7/70058; G03F7/70091; G03F7/701; G03F7/70566
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
148 words
An off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices comprising: a source of light for exposing the photosensitive film; a photomask which contains a magnified image of pattern etched into a metallic layer, said photomask being interposed between the source of light and the photosensitive film to be exposed; a lens system between the photomask and the resist for reducing the size of an illuminated image for patterning into the photosensitive film on the device substrate; and an aperture plate positioned between the source of light and the photomask, said aperture plate allowing the off axis exposure of the photosensitive film to be separated into two or more exposures, each of said two or more exposures being separately time optimized to avoid pattern shortening in a projected image of the photomask on the photosensitive film.
Claim 2
Dependent Claim
148 words
An off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices comprising: a source of light for exposing the photosensitive film; a photomask which contains a magnified image of pattern etched into a metallic layer, said photomask being interposed between the source of light and the photosensitive film to be exposed; a lens system between the photomask and the resist for reducing the size of an illuminated image for patterning into the photosensitive film on the device substrate; and an aperture plate positioned between the source of light and the photomask, said aperture plate allowing the off axis exposure of the photosensitive film to be separated into two or more exposures, each of said two or more exposures being separately time optimized to avoid pattern shortening in a projected image of the photomask on the photosensitive film.
Claim 3
Dependent Claim
186 words
An off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices comprising: a source of light for exposing the photosensitive film; a photomask which contains a magnified image of pattern etched into a metallic layer, said photomask being interposed between the source of light and the photosensitive film to be exposed; a lens system between the photomask and the resist for reducing the size of an illuminated image for patterning into the photosensitive film on the device substrate; and an aperture plate positioned between the source of light and the photomask, said aperture plate allowing the off axis exposure of the photosensitive film to be separated into two or more exposures, each of said two or more exposures being separately time optimized to avoid pattern shortening in a projected image of the photomask on the photosensitive film; wherein said aperture plate is a dipole aperture plate having two off center apertures on a common said aperture plate being rotated between exposure doses to separate the exposure of the photosensitive film into two or more exposures.
Claim 4
Dependent Claim
186 words
An off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices comprising: a source of light for exposing the photosensitive film; a photomask which contains a magnified image of pattern etched into a metallic layer, said photomask being interposed between the source of light and the photosensitive film to be exposed; a lens system between the photomask and the resist for reducing the size of an illuminated image for patterning into the photosensitive film on the device substrate; and an aperture plate positioned between the source of light and the photomask, said aperture plate allowing the off axis exposure of the photosensitive film to be separated into two or more exposures, each of said two or more exposures being separately time optimized to avoid pattern shortening in a projected image of the photomask on the photosensitive film; wherein said aperture plate is a dipole aperture plate having two off center apertures on a common said aperture plate being rotated between exposure doses to separate the exposure of the photosensitive film into two or more exposures.
Claim 5
Dependent Claim
39 words
The off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices as recited in claim 2 wherein said aperture plate is characterized by two circular off center apertures.
Claim 6
Dependent Claim
41 words
The off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices as recited in claim 2 wherein said aperture plate is characterized by two generally pie shaped off center apertures.
Claim 7
Dependent Claim
190 words
An off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices comprising: a source of light for exposing the photosensitive film; a photomask which contains a magnified image of pattern etched into a metallic layer, said photomask being interposed between the source of light and the photosensitive film to be exposed; a lens system between the photomask and the resist for reducing the size of an illuminated image for patterning into the photosensitive film on the device substrate; an aperture plate positioned between the source of light and the photomask, said aperture plate allowing the off axis exposure of the photosensitive film to be separated into two or more exposures, each of said two or more exposures being separately time optimized to avoid pattern shortening in a projected image of the photomask on the photosensitive film; and a polarizer interposed between said source of light and said aperture plate, said aperture plate having apertures filled with polarizing film, said aperture plate being rotated between exposure doses to separate the exposure of the photosensitive film into two or more exposures.
Claim 8
Dependent Claim
190 words
An off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices comprising: a source of light for exposing the photosensitive film; a photomask which contains a magnified image of pattern etched into a metallic layer, said photomask being interposed between the source of light and the photosensitive film to be exposed; a lens system between the photomask and the resist for reducing the size of an illuminated image for patterning into the photosensitive film on the device substrate; an aperture plate positioned between the source of light and the photomask, said aperture plate allowing the off axis exposure of the photosensitive film to be separated into two or more exposures, each of said two or more exposures being separately time optimized to avoid pattern shortening in a projected image of the photomask on the photosensitive film; and a polarizer interposed between said source of light and said aperture plate, said aperture plate having apertures filled with polarizing film, said aperture plate being rotated between exposure doses to separate the exposure of the photosensitive film into two or more exposures.
Claim 9
Dependent Claim
55 words
The off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices as recited in claim 5 wherein said aperture plate is characterized by off center apertures on two mutually perpendicular axes, polarizations of films of said apertures on said two axes being mutually perpendicular.
Claim 10
Independent Claim
141 words
A method of avoiding pattern shortening in an off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices comprising the steps of: providing a source of light for exposing the photosensitive film; interposing a photomask which contains a magnified image of pattern etched into a metallic layer between the source of light and the photosensitive film to be exposed; reducing the size of an illuminated image for patterning into the photosensitive film on the device substrate; positioning an aperture plate between the source of light and the photomask; and separating the off axis exposure of the photosensitive film into two or more exposures by rotating the aperture plate between exposures, each exposure being separately optimized to avoid pattern shortening in a projected image of the photomask on the photosensitive film.
Claim 11
Independent Claim
141 words
A method of avoiding pattern shortening in an off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices comprising the steps of: providing a source of light for exposing the photosensitive film; interposing a photomask which contains a magnified image of pattern etched into a metallic layer between the source of light and the photosensitive film to be exposed; reducing the size of an illuminated image for patterning into the photosensitive film on the device substrate; positioning an aperture plate between the source of light and the photomask; and separating the off axis exposure of the photosensitive film into two or more exposures by rotating the aperture plate between exposures, each exposure being separately optimized to avoid pattern shortening in a projected image of the photomask on the photosensitive film.
Claim 12
Independent Claim
180 words
A method of avoiding pattern shortening in an off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices comprising the steps of: providing a source of light for exposing the photosensitive film; interposing a photomask which contains a magnified image of pattern etched into a metallic layer between the source of light and the photosensitive film to be exposed; reducing the size of an illuminated image for patterning into the photosensitive film on the device substrate: positioning an aperture plate between the source of light and the photomask; and separating the off axis exposure of the photosensitive film into two or more exposures by rotating the aperture plate between exposures, each exposure being separately optimized to avoid pattern shortening in a projected image of the photomask on the photosensitive film, wherein the aperture plate is a dipole aperture plate having two off center apertures on a common axis, said aperture plate being rotated between exposure doses to separate the exposure of the photosensitive film into two or more exposures.
Claim 13
Independent Claim
180 words
A method of avoiding pattern shortening in an off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices comprising the steps of: providing a source of light for exposing the photosensitive film; interposing a photomask which contains a magnified image of pattern etched into a metallic layer between the source of light and the photosensitive film to be exposed; reducing the size of an illuminated image for patterning into the photosensitive film on the device substrate: positioning an aperture plate between the source of light and the photomask; and separating the off axis exposure of the photosensitive film into two or more exposures by rotating the aperture plate between exposures, each exposure being separately optimized to avoid pattern shortening in a projected image of the photomask on the photosensitive film, wherein the aperture plate is a dipole aperture plate having two off center apertures on a common axis, said aperture plate being rotated between exposure doses to separate the exposure of the photosensitive film into two or more exposures.
Claim 14
Independent Claim
183 words
A method of avoiding pattern shortening in an off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices comprising the steps of: providing a source of light for exposing the photosensitive film; interposing a photomask which contains a magnified image of pattern etched into a metallic layer between the source of light and the photosensitive film to be exposed; reducing the size of an illuminated image for patterning into the photosensitive film on the device substrate; positioning an aperture plate between the source of light and the photomask; separating the off axis exposure of the photosensitive film into two or more exposures by rotating the aperture plate between exposures, each exposure being separately optimized to avoid pattern shortening in a projected image of the photomask on the photosensitive film; and interposing a polarizer between said source of light and said aperture plate, said aperture plate having apertures filled with polarizing film, said aperture plate being rotated between exposure doses to separate the exposure of the photosensitive film into two or more exposures.
Claim 15
Independent Claim
183 words
A method of avoiding pattern shortening in an off axis illumination system for photolithographic exposure of a photosensitive film on a device substrate in the manufacture of semiconductor devices comprising the steps of: providing a source of light for exposing the photosensitive film; interposing a photomask which contains a magnified image of pattern etched into a metallic layer between the source of light and the photosensitive film to be exposed; reducing the size of an illuminated image for patterning into the photosensitive film on the device substrate; positioning an aperture plate between the source of light and the photomask; separating the off axis exposure of the photosensitive film into two or more exposures by rotating the aperture plate between exposures, each exposure being separately optimized to avoid pattern shortening in a projected image of the photomask on the photosensitive film; and interposing a polarizer between said source of light and said aperture plate, said aperture plate having apertures filled with polarizing film, said aperture plate being rotated between exposure doses to separate the exposure of the photosensitive film into two or more exposures.
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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) | 2001-09-28 | 2002-03-30 | 2002-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-09-28 | 2006-03-30 | 2006-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-09-28 | 2010-03-30 | 2010-09-29 | $7700.00 | Window Closed / Lapsed |