Optics: measuring and testing – By alignment in lateral direction – With registration indicia
Patent
1981-05-20
1983-09-20
Rosenberger, R. A.
Optics: measuring and testing
By alignment in lateral direction
With registration indicia
356363, 356375, 35016216, G01B 902, G01B 1100
Patent
active
044052383
ABSTRACT:
Fine alignment of mask and wafer, using Fresnel zone plates is achieved. Light is focused on the wafer by a zone plate in the mask. Light diffracted from a zone plate on the wafer is received by a sensor. The received light is coded (analog or digital) to indicate alignment. For analog coding the wafer zone plate diffracts light to the sensor from an area of the wafer zone plate which is indicative of alignment. For digital coding, the wafer zone plate is digitally encoded as a function of alignment to similarly code the diffracted light. To eliminate ambiguity, the mask zone plate is formed from a plurality of "elements", each of which is itself a Fresnel zone plate. The focal length of the elemental Fresnel zone plate can be related to the mask/wafer separation distance, whereas the focal length of the macro zone plate (made up of a plurality of the elemental zone plates) is related to the distance between mask and light sensor.
REFERENCES:
patent: 4037969 (1977-07-01), Feldman et al.
patent: 4311389 (1982-01-01), Fay et al.
Grobman Warren D.
Nelson, Jr. David A.
Warlaumont John M.
IBM Corporation
Rosenberger R. A.
LandOfFree
Alignment method and apparatus for x-ray or optical lithography does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Alignment method and apparatus for x-ray or optical lithography, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Alignment method and apparatus for x-ray or optical lithography will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-585619