Method for measuring alignment accuracy in a step and repeat system utilizing different intervals
US5830610A · kind A · utility
5Cited by
0References
28Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 15, 1996 |
| Grant date | Nov 3, 1998 |
| Priority date | — |
| Expiry date | Oct 15, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70691
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method for measuring alignment accuracy in a step and repeat system which includes projecting an array of rows and columns of grating features onto a wafer coated with a resist using a first stepping distance and using an increased exposure dosage from row to row of said array; projecting the same array over the first but using a different stepping distance along the rows and also a sufficient offset in the starting positions of the first and second exposures to form a phase difference between the two projection exposures which will result in a complementary alignment of the two exposures at least one column in the array.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.