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US 4,541,715 AGranted
Apparatus for detecting contaminants on the reticle of exposure system
AssigneeHitachi, Ltd.
InventorsNobuyuki Akiyama, Mitsuyoshi Koizumi
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AssigneeHitachi, Ltd.
InventorsNobuyuki Akiyama, Mitsuyoshi Koizumi
Estimating the term…
An apparatus for detecting contaminants depositing on the reticle of a reduction projection mask aligner comprises a laser spot projector which conducts a laser beam to the light path upstream of the condenser lens of the aligner such that the laser beam is in the same direction as of the exposure light beam. The laser spot projector projects the laser beam from above the reticle through the condenser lens so as to form a laser spot on the upper surface of the reticle. A laser spot scanner which scans the entire area of the reticle by the laser spot projected on to the reticle by the laser spot projector, and a photoelectric detector which receives the scattered light emitted aslant on the reticle surface, whereby a contaminant on the reticle is detected in accordance with the signal produced by the detector.
An apparatus for detecting contaminants on a reticle mounted in an exposure system in which a light beam converged by a condenser lens is projected onto said reticle having a circuit pattern thereon so that an image of said pattern is focused on a photoresist coated on a wafer or a mask, said apparatus comprising:
An apparatus for detecting contaminants comprising means for projecting a laser beam through a condenser lens above a reticle mounted in a reduction projection mask aligner onto the upper surface of said reticle so as to form a laser spot thereon, means for swinging said laser beam so that the entire area of said reticle is scanned by said laser spot, and scattered light is emitted aslant from the reticle surface by impingement of said laser spot on contaminants on said reticle surface, photoelectric detector means for receiving said scattered light and for producing a signal indicative of the presence of contaminants on said reticle in accordance therewith.
An apparatus for detecting contaminants comprising means for projecting laser beams from above and from under a reticle mounted in a reduction projection mask aligner so as to form a laser spot on each of the upper and lower surfaces of said reticle, means for swinging said laser beams so that the entire area of said reticle is scanned by said laser spots in X and Y directions and scattered light is emitted aslant on the reticle surfaces by impingement of said laser spots on contaminants on said upper and lower reticle surface, and Photoelectric detector means for receiving said scattered light and for producing a signal indicative of the presence of contaminants on said reticle in accordance therewith.
Dependencies are inferred from the claim text.