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US5140469A Expired / Lapsed US ⏱️ 0.0 years remaining

Illumination apparatus for semiconductor fabrication including conical optical means

Assignee: Raytheon Co
•
Filing: 1992-01-03
•
Granted: 1992-08-18
•
Expires: 2012-01-03
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Abstract

Abstract A method of patterning a photoresist layer to provide an aperture having retrograde sidewalls is described. Illumination may be through a conical prism arrangement or a conical reflecting mirror and cylindrical mirror arrangement. The method includes the step of directing energy towards a mask which selectively exposes portions of a photoresist layer disposed on the substrate. The energy is directed to the mask at an oblique angle with respect to the normal to the surface of the substrate. The underlying photoresist layer is obliquely sensitized by the obliquely directed illumination. The portions of the layer which are obliquely sensitized are removed leaving behind an aperture having retrograde sidewalls. The retrograde sidewalls are a preferred photoresist profile for easy and reliable lift-off of deposited material from the semiconductor substrate.

Inventors

  • 👤 Philip A. Lamarre
  • 👤 Robert L. Mozzi

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-03 14:58
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70058; G03F7/70091; G03F7/70108; G03F7/20; G03F7/2002; G03F7/70216; G03F7/7035

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 102 words
Apparatus comprising: means for providing collimated optical energy; conical means disposed in a path of said directed optical energy for directing said energy over a surface area of a substrate in an oblique angle with respect to an angle of incidence of said directed optical energy; filtering means, disposed between said means for providing collimated optical energy and said conical means, for providing a reduction in the intensity of illumination of said collimated optical energy passing therethrough; and wherein said filtering means in combination with said conical means provides said collimated energy at a uniform intensity over said surface of said substrate.
Claim 2
Dependent Claim 102 words
Apparatus comprising: means for providing collimated optical energy; conical means disposed in a path of said directed optical energy for directing said energy over a surface area of a substrate in an oblique angle with respect to an angle of incidence of said directed optical energy; filtering means, disposed between said means for providing collimated optical energy and said conical means, for providing a reduction in the intensity of illumination of said collimated optical energy passing therethrough; and wherein said filtering means in combination with said conical means provides said collimated energy at a uniform intensity over said surface of said substrate.
Claim 3
Dependent Claim 34 words
Apparatus, as recited in claim 1, wherein said conical means includes a transmitting conical prism having an incidence surface disposed at an angle related to an angle at which the energy is obliquely directed.
Claim 4
Dependent Claim 34 words
The apparatus, as recited in claim 1, wherein said conical means includes a conical reflecting mirror and a cylindrical mirror with said conical reflecting mirror disposed within a reflecting portion of said cylindrical mirror.
Claim 5
Dependent Claim 38 words
The apparatus, as recited in claim 1, wherein said conical means includes a Fresnel lens reduction which provides, in response to optical energy directed at said lens, optical energy from said Fresnel lens at the desired oblique angle.
Claim 6
Dependent Claim 37 words
Apparatus as recited in claim 1, wherein said filtering means is a radial gradient neutral density filter, said filter gradually varying the intensity of the illumination as a function of a radial sector of said conical means.

References Cited (Backward Citations)

US2882784A Cited
US3419321A Cited
US3663090A Cited
US4312330A Cited
US4514040A Cited
US4653472A Cited
US4909587A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1995-08-18 1996-02-17 1996-08-18 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1999-08-18 2000-02-17 2000-08-18 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2003-08-18 2004-02-17 2004-08-18 $7700.00 Window Closed / Lapsed

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