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Patent US4977426A successfully refreshed from Google Patents.
US4977426A
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Projection exposure apparatus
Assignee: Canon Inc
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Filing: 1988-06-24
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Granted: 1990-12-11
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Expires: 2008-06-24
Abstract
Abstract A projection exposure apparatus for projecting, through a refracting optical system, a pattern formed on an original such as a mask or reticle onto a wafer. The projection exposure apparatus includes a light source for providing an excimer laser beam to illuminate the original. The refracting optical system includes a plurality of lenses each of which is made of fused silica (SiO 2 ) or calcium fluoride (CaF 2 ).
Inventors
- 👤 Ryusho Hirose
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:52
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70216; G03F7/70241
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
86 words
A projection exposure apparatus, comprising: a light source device providing a band-narrowed excimer laser beam; a projection lens system for projecting a pattern of an original on a wafer, said projection lens system including a plurality of non-cemented lens elements made of different materials having sufficient transmissibility with respect to the excimer laser beam; and means for supporting the original and the wafer so that the pattern of the original can be projected on the wafer by said projection lens system with the excimer laser beam.
Claim 2
Dependent Claim
86 words
A projection exposure apparatus, comprising: a light source device providing a band-narrowed excimer laser beam; a projection lens system for projecting a pattern of an original on a wafer, said projection lens system including a plurality of non-cemented lens elements made of different materials having sufficient transmissibility with respect to the excimer laser beam; and means for supporting the original and the wafer so that the pattern of the original can be projected on the wafer by said projection lens system with the excimer laser beam.
Claim 3
Dependent Claim
23 words
An apparatus according to claim 1, wherein said lens elements of said projection lens system are made of fused silica and calcium fluoride.
Claim 4
Dependent Claim
16 words
An apparatus according to claim 2, wherein said projection lens system provides a reduction imaging system.
Claim 5
Dependent Claim
16 words
An apparatus according to claim 2, wherein said light source device includes an injection-locked excimer laser.
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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) | 1993-12-10 | 1994-06-11 | 1994-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-10 | 1998-06-11 | 1998-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-10 | 2002-06-11 | 2002-12-11 | $7700.00 | Window Closed / Lapsed |