Method of and system for charged particle beam exposure
US5719402A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 4, 1996 |
| Grant date | Feb 17, 1998 |
| Priority date | — |
| Expiry date | Apr 4, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/1504
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
To improve the throughput of an exposure system, the setting time during a step change in the output of an amplifier is reduced by switching resistance between the amplifier and a deflector. A glitch waveform generated during a step change in the output of a D/A converter at the preceding stage of the amplifier is anticipated and is cancelled out with a correction waveform. After the output of the D/A converter has settled, this output is sample-held and the step change is interpolated with a smoothing circuit. The deflection area is increased by positioning an electrostatic deflector offset around the optical axis relative to another electrostatic deflector, and the response speed of the main deflection is improved by adding auxiliary deflection coils of one or two turns. The alignment time is reduced by combining the coordinate conversion in the wafer area and in the chip area. In order to correct the astigmatism of the electromagnetic lens, two stages of coils are provided and an electric current corresponding to the quantity of deflection is supplied to the coils.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.