Apparatus and method for inspecting a mask
US4958074A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jul 13, 1988 |
| Grant date | Sep 18, 1990 |
| Priority date | — |
| Expiry date | Jul 13, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/22
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An apparatus and method for inspecting X-ray and corpuscular beam, e.g., electron or ion beam, lithography masks for defects. The apparatus includes a stage to support the mask in the path of a corpuscular inspection beam projected from a beam source above the stage, an emitter surface below the stage for emitting secondary radiation resulting from the impingement of the inspection beam that has passed through the mask onto the emitter surface, a detector arranged to receive the secondary radiation to generate image signals corresponding to this secondary radiation, and an image storage device to receive and store the image signals. The stage is moved in a stepwise fashion to bring individual mask fields that can be scanned by the beam in a single step into the beam path until all of the fields of a given mask have been scanned. The image signal of the actual mask is compared to a stored reference to detect defects which may also be repaired by the same apparatus according to preferred embodiments.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.