Importance

Loading Importance Indicators...

Abstract

A system to sense an aerial image produced by optical equipment used in, for example, semiconductor fabrication. In one embodiment, the system includes a photo-electron emission device which, in response to an aerial image projected thereon, emits electrons in a pattern corresponding to the light intensity distribution produced by the aerial image. Electron optics provides an enlarged pattern of the pattern in which the electrons are emitted. A sensing unit senses the enlarged pattern. In another embodiment, the system employs a photo-conducting layer to project the aerial image thereon. The photo-conducting layer, in response to the projection of the aerial image thereon, produces local charge depletion corresponding to the light intensity distribution. A steering device delivers electrons to the photo-conducting layer to produce local re-charging currents in proportion to the local charge depletion. A pattern corresponding to the aerial image may be obtained from the re-charging currents.

Loading the Abstract Image...

First Claim