Method for measurement of spotsize and edgewidth in electron beam lithography
US4675528A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 28, 1985 |
| Grant date | Jun 23, 1987 |
| Priority date | — |
| Expiry date | Jun 28, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B15/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The technique of measuring the spotsize and edgewidth of an electron beam by incrementally scanning the beam through discrete scan locations across a sharp edge is improved by processing the resulting beam current signals directly rather than the differentiated beam current signal. A linear regression is performed on beam current data points expected to fall in the linear portion of the beam current versus beam position characteristic in order to provide a linear approximation of the overall characteristic. Extrapolation of the linear function to its intersections with the maximum (I.sub.1) and minimum (I.sub.0) beam current levels yields corresponding beam positions Z.sub.B and Z.sub.A, such that (Z.sub.B -Z.sub.A) is a measure of spotsize in the scan direction. Edgewidth between the twelve and eighty-eight percent amplitude levels is obtained by locating measured beam currents at incremental scan locations on both sides of beam positions Z.sub.A and Z.sub.B, and interpolating to find the actual beam currents I.sub.A and I.sub.B at these positions. Edgewidths D.sub.A and D.sub.B are computed as D.sub.A =4.sqroot..pi.(Z.sub.B -Z.sub.A)(I.sub.A -I.sub.0)(I.sub.1 -I.sub.0) and D.sub.…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.