Method of measuring numerical aperture of exposure machine, control wafer, photomask, and method of monitoring numerical aperture of exposure machine
US8134708B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 2008 |
| Grant date | Mar 13, 2012 |
| Priority date | — |
| Expiry date | Apr 29, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/706
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of measuring a numerical aperture of an exposure machine is described. A control wafer having vernier marks thereon and an aberration mask having pinholes therein are provided, wherein each pinhole corresponds to a vernier mark in position. A lithography process using the exposure machine and the aberration mask is performed to the control wafer, so as to form over each vernier mark a photoresist pattern having the same shape of the illumination pattern of the light source of the exposure machine. The numerical aperture of the exposure machine is then derived from a graduation of the vernier mark corresponding to an outer edge of the photoresist pattern.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.