Charged particle exposure system having a capability of checking the shape of a charged particle beam used for exposure
US5404019A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Nov 26, 1993 |
| Grant date | Apr 4, 1995 |
| Priority date | — |
| Expiry date | Nov 26, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/31776
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A charged particle beam exposure system checks for the shape of the charged particle beam shaped by a mask by causing a scanning of a marker pattern provided on a substrate along a scanning path. The reflected electrons emitted from the substrate are detected, and the shape of the charged particle beam is obtained based upon the profile of the reflected electrons along the scanning path. By comparing expected pattern of the reflected charged particles, one can detect anomaly in the beam shaping aperture on the mask, wherein the step for comparing the observed pattern and the expected pattern includes a step of pattern matching for shifting the patterns with each other for seeking a minimum of unoverlapped area of the patterns. When the difference between the observed pattern and the expected pattern exceeds a threshold in the state that the unoverlapped area is minimized, an alarm produced with the information indicative of the location of the pattern wherein the threshold has been exceeded.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.