Method of characterizing linewidth errors in a scanning lithography system
US5985498A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 1, 1999 |
| Grant date | Nov 16, 1999 |
| Priority date | — |
| Expiry date | Mar 1, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70625
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of characterizing linewidth errors in a lithography system 30 used to delineate a desired pattern onto an exposure site of a wafer 32. The pattern of a reticle 34 is transferred onto an exposure site 56 of a wafer 32 by projecting a slit of light extending in a slit direction y through the reticle while scanning the reticle and the wafer in a scanning direction x relative to the lens. The exposure site 56 is conceptually divided into a grid having one series of lines extending in the scan direction x and another series of lines extending in the slit direction y whereby points corresponding to perpendicular intersections of the lines may each be assigned a pair of coordinates (x,y). The linewidths of the pattern are measured for each of the points (x,y) and a linewidth error value ERROR (x,y) is generated for each of the points (x,y). An ERROR.sub.optical (y) value for each y coordinate is calculated by averaging the ERROR (x,y) values for each group of points (x,y) having a common y coordinate. In this manner, the contribution of optical aberrations to linewidth errors may be determined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.