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US5003345A Expired / Lapsed US ⏱️ 0.0 years remaining

Apparatus and method for aligning and focusing an image of a reticle onto a semiconductor wafer

Assignee: Ultratech Inc
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Filing: 1989-12-27
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Granted: 1991-03-26
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Expires: 2009-12-27
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Abstract

Abstract A projection system provides a primary mirror with a thin nearly concentric shell which functions as a first mirror at shorter wavelengths for exposure purposes and functions as a second mirror surface at longer wavelengths for alignment purposes. The coating on the front surface of the shell is reflective to the exposing wavelengths and transmissive to the alignment illumination, and the coating on the back of the shell is reflective to the alignment wavelengths. This provides good focus and alignment of the images over two spectral regions.

Inventors

  • 👤 David A. Markle

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-01 11:18
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70216; G03F7/70225; G03F9/00; G03F9/70

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 116 words
In a projection system including a wafer, a reticle, and light source where said light source includes alignment light wavelengths for aligning the image of said reticle to said wafer and light wavelengths for exposing said image onto said wafer, the apparatus comprising primary mirror means including a thin substantially concentric shell having a front and back surface, said front surface including means for reflecting said exposure wavelengths from said reticle to said wafer to expose said image onto said wafer, and means for transmitting said alignment wavelengths to said back surface, said back surface of said shell including means for reflecting said alignment wavelengths to said wafer to align said reticle image to said wafer.
Claim 2
Dependent Claim 116 words
In a projection system including a wafer, a reticle, and light source where said light source includes alignment light wavelengths for aligning the image of said reticle to said wafer and light wavelengths for exposing said image onto said wafer, the apparatus comprising primary mirror means including a thin substantially concentric shell having a front and back surface, said front surface including means for reflecting said exposure wavelengths from said reticle to said wafer to expose said image onto said wafer, and means for transmitting said alignment wavelengths to said back surface, said back surface of said shell including means for reflecting said alignment wavelengths to said wafer to align said reticle image to said wafer.
Claim 3
Dependent Claim 109 words
A projection system comprising a wafer, a reticle, a light source having alignment light wavelengths for aligning the image of said reticle to said wafer, and exposure light wavelengths for exposing said image onto said wafer, primary mirror means including a thin substantially concentric shell having a front and back surface, said front surface including means for reflecting said exposure wavelengths from said reticle to said wafer to expose said image onto said wafer, and means for transmitting said alignment wavelengths to said back surface, said back surface of said shell including means for reflecting said alignment wavelengths to said wafer to align said reticle image to said wafer.
Claim 4
Dependent Claim 109 words
A projection system comprising a wafer, a reticle, a light source having alignment light wavelengths for aligning the image of said reticle to said wafer, and exposure light wavelengths for exposing said image onto said wafer, primary mirror means including a thin substantially concentric shell having a front and back surface, said front surface including means for reflecting said exposure wavelengths from said reticle to said wafer to expose said image onto said wafer, and means for transmitting said alignment wavelengths to said back surface, said back surface of said shell including means for reflecting said alignment wavelengths to said wafer to align said reticle image to said wafer.
Claim 5
Dependent Claim 111 words
In a projection system including a wafer, a reticle, and light source means where said light source has alignment light wavelengths for aligning the image of said reticle to said wafer and wavelengths for exposing said image onto said wafer, primary mirror means including a thin substantially concentric shell having a front and back surface, the method comprising the steps of transmitting said alignment wavelengths through said front surface to said back surface, reflecting said alignment wavelengths from said back surface to said wafer to align said reticle image to said wafer, and reflecting said exposure wavelengths from said front surface to said wafer to expose said image onto said wafer.
Claim 6
Dependent Claim 111 words
In a projection system including a wafer, a reticle, and light source means where said light source has alignment light wavelengths for aligning the image of said reticle to said wafer and wavelengths for exposing said image onto said wafer, primary mirror means including a thin substantially concentric shell having a front and back surface, the method comprising the steps of transmitting said alignment wavelengths through said front surface to said back surface, reflecting said alignment wavelengths from said back surface to said wafer to align said reticle image to said wafer, and reflecting said exposure wavelengths from said front surface to said wafer to expose said image onto said wafer.

References Cited (Backward Citations)

US4370054A Cited
US4422754A Cited
US4572659A Cited
US4682885A Cited
US4757354A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1994-03-25 1994-09-24 1995-03-26 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1998-03-25 1998-09-24 1999-03-26 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2002-03-25 2002-09-24 2003-03-26 $7700.00 Window Closed / Lapsed

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