EP0027570A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apparatus for prealignment of a wafer
Assignee: Eaton Optimetrix Inc
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Filing: 1980-09-27
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Granted: —
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Expires: 2000-09-27
Abstract
Abstract In an optical alignment and exposure machine, particularly suited for printing microelectronic circuit patterns on semi-conductive wafers, two stages of wafer prealignment are performed, In the first stage of prealignment the periphery of the wafer engages three belt-driven rollers which turn the wafer to align a flat edge thereof with two of the rollers. A transfer arm then picks up the prealigned wafer and transfers itto a rotatable chuck on an X-Y addressable work stage. In the second stage of prealignment a pair of alignment members carried by the chuck index with the flat edge of the wafer, and another pair of alignment members carried by the chuck indexes either the center or a rounded edge of the wafer to a predetermined position. An optical alignment system permits rotation of the chuck to align alignment marks on the wafer with respect to projected images of alignment marks on the mask. The addressable work stage carrying the chuck includes apparatus for selectively moving the chuck and wafer into engagement with a stop carried by the work stage for accurately positioning the plane of an emulsion on the wafer with respect to a focal plane of the optical alignment system.
Inventors
- 👤 Edward H. Phillips
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 19:57
CPC Classifications
G; G03; G03F; G03F9/00; G03F9/70; G03F9/7003; G03F9/7007; G03F9/7011
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
127 words
In a method for prealignment of a wafer having an alignment flat formed at the periphery thereof in an optical alignment and exposure machine, the steps of: receiving a wafer at a first prealignment station; turning the wafer about an axis generally perpendicular to a plane of one of its major faces to bring the alignment flat on the wafer into alignment with a reference operatively associated with the first prealignment station to derive a first stage of prealignment; transferring the first stage prealigned wafer directly to a rotatable alignment and exposure chuck while maintaining the first stage prealignment of the wafer; and aligning the flat on the wafer with a second reference operatively associated wtih said chuck to derive a second stage of more precise prealignment.
Claim 2
Dependent Claim
127 words
In a method for prealignment of a wafer having an alignment flat formed at the periphery thereof in an optical alignment and exposure machine, the steps of: receiving a wafer at a first prealignment station; turning the wafer about an axis generally perpendicular to a plane of one of its major faces to bring the alignment flat on the wafer into alignment with a reference operatively associated with the first prealignment station to derive a first stage of prealignment; transferring the first stage prealigned wafer directly to a rotatable alignment and exposure chuck while maintaining the first stage prealignment of the wafer; and aligning the flat on the wafer with a second reference operatively associated wtih said chuck to derive a second stage of more precise prealignment.
Claim 3
Dependent Claim
58 words
The method of claim 1 including the step of rotating said chuck with said prealigned wafer thereon to an angular position to align alignment marks on the wafer with alignment marks of an image of a mask in an optical projection system such mask image to be projected onto the wafer for exposure of a photosensitive emulsion thereon.
Claim 4
Dependent Claim
67 words
The method of claim 1 including the step of: translating said chuck with the prealigned wafer thereon to successive predetermined spaced locations generally in a plane parallel to a major face of the wafer; and successively exposing a photosensitive emulsion on a major face of the wafer to a mask image pattern projected onto said ,major face of said wafer at respective ones of said predetermined locations.
Claim 5
Dependent Claim
77 words
Th.e method of claim 1 wherein the step of aligning the flat of the wafer wtih the second reference operatively associated with said chuck to derive the second stage of more precise alignment includes the steps of: urging the flat of the wafer against a pair of spaced first alignment members affixed to said alignment and exposure chuck;and indexing the curved opposite edges of said wafer to second alignment members carried from said chuck and rotatable therewith.
Claim 6
Dependent Claim
54 words
The method of claim 4 wherein said second alignment members include a pair of members which move toward each other at equal rates to press against the curved edges of the wafer from opposite sides for indexing the center of the wafer to a predetermined location between the pair of moveable second alignment members.
Claim 7
Dependent Claim
70 words
The method of claim 4 wherein said second alignment members include one indexing member fixed in a predetermined position on said chuck to index with a curved side edge of the wafer and a second moveable member moveable toward said fixed indexing member and positioned to press against the opposite curved side edge of the wafer for aligning the opposite side edge of said wafer with said fixed indexing member.
Claim 8
Dependent Claim
75 words
The method of claim 2 including the steps of: transferring said exposed wafer from said chuck; and transferring a second first stage prealigned wafer onto said chuck while maintaining the previously optically aligned angular position of said chuck as determined for the first wafer; and aligning the flat on said second wafer with said reference operatively associated with said chuck at said previously aligned angular position to derive the second stage of more precise prealignment.
Claim 9
Dependent Claim
93 words
The method of claim 1 including the steps of: translating said chuck with the prealigned wafer thereon in a direction orthogonal to one of the major faces of said wafer into a predetermined plane of position relative to a focal plane of an optical projection system and relative to a reference plane carried from a work stage translatable in a plane parallel to the major face of the wafer; and exposing a phtosensitive emulsion a major face of the wafer to a mask image pattern projected onto said major face of said wafer.
Claim 10
Dependent Claim
170 words
In an apparatus for prealignment of a wafer having an alignment flat formed at the periphery thereof in an optical alignment and exposure machine; first prealignment station means for receiving a wafer and for performing a first stage of prealignment by turning the wafer about an axis generally perpendicular to a plane of one of its major faces to bring the alignment flat on the wafer into alignment with a reference operatively associated with said first prealignment station to derive a first stage of prealignment; alignment and exposure chuck means for performing a second stage of mechanical alignment of the wafer and for exposing a photosensitive emulsion on the aligned wafer, said alignment and exposure chuck means including means for aligning the flat on the Wafer with a second reference operatively associated with said fhuck to derive a second stage of more precise prealignment; and means for transferring the first stage prealigned wafer directly to said alignment and exposure chuck means while maintaining the first stage prealignment of the wafer.
Claim 11
Dependent Claim
170 words
In an apparatus for prealignment of a wafer having an alignment flat formed at the periphery thereof in an optical alignment and exposure machine; first prealignment station means for receiving a wafer and for performing a first stage of prealignment by turning the wafer about an axis generally perpendicular to a plane of one of its major faces to bring the alignment flat on the wafer into alignment with a reference operatively associated with said first prealignment station to derive a first stage of prealignment; alignment and exposure chuck means for performing a second stage of mechanical alignment of the wafer and for exposing a photosensitive emulsion on the aligned wafer, said alignment and exposure chuck means including means for aligning the flat on the Wafer with a second reference operatively associated with said fhuck to derive a second stage of more precise prealignment; and means for transferring the first stage prealigned wafer directly to said alignment and exposure chuck means while maintaining the first stage prealignment of the wafer.
Claim 12
Dependent Claim
58 words
1Q. The apparatus of claim 9 including means for rotating said alginment and exposure chuck means with said prealigned wafer thereon to align alignment marks on the wafer with alignment marks of an image of a mask in an optical projection system, such mask image to be projected onto the wafer for exposure of a photosensitive emulsion thereon.
Claim 13
Dependent Claim
70 words
The apparatus of claim 9 including: means for translating said alignment and exposure chuck with the prealigned wafer thereon to successive predetermined spaced locations generally in a plane parallel to a major face of the wafer; and means for successively exposing a photosensitive emulsion on a major face of the wafer to a mask image pattern projected onto said major face of said wafer at each of said predetermined locations.
Claim 14
Dependent Claim
82 words
The apparatus of claim 9 wherein said alignment and exposure chuck means includes; a pair of spaced alignment means affixed to said alignment 'and exposure chuck means for indexing with the alignment flat of the wafer; means for urging the flat of the wafer against said pair of spaced alignment means; second alignment means carried from said alignment and exposure chuck means and rotatable therewith; and means for indexing the curved opposite side edges of said wafer with said second alignment means.
Claim 15
Dependent Claim
47 words
The apparatus of claim 12 wherein said second alignment means move toward each other at equal rates to press against the curved edges of the wafer from opposite sides for indexing the center of the.wafer to a predetermined location between said pair of moveable second alignment means.
Claim 16
Dependent Claim
80 words
The apparatus of claim 12 wherein said second alignment means includes one indexing means fixed in a predetermined position on said alignment and exposure chuck means for indexing with a curved side edge of the wafer, and wherein said second alignment means includes a second means moveable toward said one fixed indexing means and positioned to press against an opposite curved side edge of the wafer for aligning one side edge of said wafer with. said one fixed indexing means.
Claim 17
Dependent Claim
85 words
The apparatus of claim 10 including: means for transferring said exposed wafer from said alignment and exposure chuck means; means for maintaining the previously optically aligned angular position of said chuck while transferring a second first stage prealigned wafer onto said chuck; and wherein said alignment and exposure chuck means aligns the flat on said second wafer with said second reference operatively associated with- said alignment and exposure chuck means at the previously aligned angular position to derive the second stage of .more precise prealignment.
Claim 18
Dependent Claim
107 words
The apparatus of claim 9 including: work stage means for translating said chuck means in a plane parallel to a major face of the wafer; means for translating said alignment and exposure chuck means with the prealigned wafer theron in a direction orthogonal to one of the major faces of said wafer into a predetermined plane of position relative to a focal plane of an optical projection system and relative to a reference plane carried from said work stage means; and means for exposing a photosensitive emulsion on a major face of the wafer to a mask image pattern projected onto said major face of said wafer.
References Cited (Backward Citations)
No citation records indexed.
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