US3963353A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Monolithic beam splitter mirror arrangement
Assignee: SVG LITHOGRAPHY Inc A CORP OF
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Filing: 1974-09-26
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Granted: 1976-06-15
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Expires: 1994-09-26
Abstract
Abstract A beam splitter is incorporated as one of the mirrors in a three mirror folding array in a projection system for exposing wafers used in making micro circuits. Through the use of the beam splitter, it is possible to view the wafer for alignment purposes while avoiding the drawbacks of viewing through the back of the master which is being imaged on the wafer.
Inventors
- 👤 Harold S. Hemstreet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:37
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70216; G03F7/70358; G02; G02B; G02B27/00; G02B27/10; G02B27/1006; G02B27/14; G02B27/141; G02B27/143; G03F9/00; G03F9/70
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
232 words
In an optical projection system wherein the image of a preselected portion on a master is projected onto a wafer, the projection system including, between the master and the wafer, a plurality of reflective surfaces angularly disposed for folding the optical path of the system, an improved arrangement for viewing the image projected on the wafer comprising: said reflective surfaces being provided respectively by different reflective faces of a single monolithic structure, said structure having an aperture therethrough opening through one of said faces, the reflective surface of said one face being provided by a beam splitting plate on the one face and over the opening of said aperture therethrough, said aperture being aligned for the portion of reimaging light that is reflected back through the system from the wafer and that passes through said beam splitting plate to pass through said structure, optical correcting means in the path of the portion of reimaging light that passes through said aperture to compensate for distortion introduced in the latter portion of reimaging light by the angle at which this light passes through said beam splitting plate, and objective lens means and viewing means in the path of light emerging through the optical correcting means for viewing the composite reimage of said portion of the master and the portion of the wafer on which the image of said portion of the master is projected.
Claim 2
Dependent Claim
232 words
In an optical projection system wherein the image of a preselected portion on a master is projected onto a wafer, the projection system including, between the master and the wafer, a plurality of reflective surfaces angularly disposed for folding the optical path of the system, an improved arrangement for viewing the image projected on the wafer comprising: said reflective surfaces being provided respectively by different reflective faces of a single monolithic structure, said structure having an aperture therethrough opening through one of said faces, the reflective surface of said one face being provided by a beam splitting plate on the one face and over the opening of said aperture therethrough, said aperture being aligned for the portion of reimaging light that is reflected back through the system from the wafer and that passes through said beam splitting plate to pass through said structure, optical correcting means in the path of the portion of reimaging light that passes through said aperture to compensate for distortion introduced in the latter portion of reimaging light by the angle at which this light passes through said beam splitting plate, and objective lens means and viewing means in the path of light emerging through the optical correcting means for viewing the composite reimage of said portion of the master and the portion of the wafer on which the image of said portion of the master is projected.
Claim 3
Dependent Claim
43 words
The arrangement of claim 1 includes lamp means for directing illumination into the optical system through said aperture said lamp providing illumination of a color different from illumination utilized in the optical system for projecting the image of the master onto the wafer.
Claim 4
Dependent Claim
32 words
The arrangement of claim 1 including at least two objective lens means in the path of said remaining light through the aperture and positioned for viewing respectively different portions of said reimage.
Claim 5
Dependent Claim
52 words
The arrangement of claim 3 including field splitting means respectively in the optical paths from said two objective lenses to the viewing means for passing only a portion of the image area observed through each of the objective lenses, and combining means for passing the latter image areas to the viewing means.
References Cited (Backward Citations)
US2765704A
Cited
US3718396A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-15 | 1979-12-15 | 1980-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-15 | 1983-12-15 | 1984-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-15 | 1987-12-15 | 1988-06-15 | $7700.00 | Window Closed / Lapsed |