System for improving the uniformness of patterns generated by electron beam lithography
US4500790A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 19, 1982 |
| Grant date | Feb 19, 1985 |
| Priority date | — |
| Expiry date | Oct 19, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/304
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A system to improve the uniformness of patterns for LSI circuits or masks generated in an electron beam lithographic system uses a backscatter indicator signal to vary a control signal for the beam stepping rate proportional to the variations in the amount of backscattered electrons. This avoids non-uniformity such as line width variations which otherwise occur when the pattern to be generated covers border lines between two different substrate or base layer materials. Range setting circuitry is provided for adjusting, during an initial prescan of a sample of two materials having an extreme difference in their backscatter characteristic, the offset and the gain for the backscatter detector. During subsequent exposure of a wafer, the backscatter indicator signal and thus the stepping rate control signal variations remain within preselected limits.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.