US4376581A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of positioning disk-shaped workpieces, preferably semiconductor wafers
Assignee: MERCOTRUST AKTIENGESELLSCHAFT A CORP OF LIECOTENSTEIN
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Filing: 1980-12-29
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Granted: 1983-03-15
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Expires: 2000-12-29
Abstract
Abstract In the photoexposure of semiconductor wafers for the production of circuit elements, the wafers are placed in a prealignment position before being transferred to the exposure stage. A chuck acting as a prepositioning stage is rotatable by one servomotor to set the wafer in its appropriate angular position (φ adjustment) and is shiftable by respective servomotors in the X and Y directions. Servomotor control is effected by optical means detecting a noncircular edge portion of the wafer as well as alignment marks on the wafer inwardly of the edge thereof.
Inventors
- 👤 Herbert E. Mayer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:32
CPC Classifications
G; G03; G03F; G03F9/00; G03F9/70; H; H10; H10P; H10P72/00; H10P72/50; H10P72/53; H10P72/57
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
137 words
A method for preparing a semiconductor wafer for the formation of a pattern of circuit elements at predetermined locations on a surface thereof by selective illumination of a photosensitive layer on such surface through a mask in an exposure station after orthogonal and angular prealignment of the wafer in a prepositioning station, comprising the steps of: (a) providing the wafer with a peripheral edge having a distinctive portion and with optical surface markings inwardly from said edge; (b) coarsely prealigning the wafer in the prepositioning station by optical detection of said distinctive edge portion and of certain of said surface markings; (c) transferring the wafer to the exposure station with the orientation imparted thereto in the prepositioning station; and (d) more precisely adjusting the wafer in said exposure station by optically detecting other of said surface markings.
Claim 2
Independent Claim
137 words
A method for preparing a semiconductor wafer for the formation of a pattern of circuit elements at predetermined locations on a surface thereof by selective illumination of a photosensitive layer on such surface through a mask in an exposure station after orthogonal and angular prealignment of the wafer in a prepositioning station, comprising the steps of: (a) providing the wafer with a peripheral edge having a distinctive portion and with optical surface markings inwardly from said edge; (b) coarsely prealigning the wafer in the prepositioning station by optical detection of said distinctive edge portion and of certain of said surface markings; (c) transferring the wafer to the exposure station with the orientation imparted thereto in the prepositioning station; and (d) more precisely adjusting the wafer in said exposure station by optically detecting other of said surface markings.
Claim 3
Dependent Claim
20 words
The method defined in claim 1 wherein said certain of said surface markings include light-scattering formations on a contrasting area.
Claim 4
Dependent Claim
19 words
The method defined in claim 2 wherein said contrasting area is light-transmissive and is transluminated by a position-detecting beam.
Claim 5
Dependent Claim
23 words
The method defined in claim 1, 2 or 3 wherein light is directed upon said certain of said surface markings from a laser.
Claim 6
Dependent Claim
40 words
The method defined in claim 1, 2 or 3 wherein said certain of said surface markings include two sets of closely spaced parallel lines at spaced-apart locations, the lines of one set being perpendicular to those of the other set.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-14 | 1986-09-13 | 1987-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-14 | 1990-09-13 | 1991-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-14 | 1994-09-13 | 1995-03-15 | $7700.00 | Window Closed / Lapsed |