Alignment method
US4881100A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 16, 1988 |
| Grant date | Nov 14, 1989 |
| Priority date | — |
| Expiry date | Nov 16, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7046
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An alignment method usable in an apparatus for transferring images of a pattern of a mask onto different portions of a semiconductor wafer in a step-and-repeat manner, is disclosed. In this alignment method, positional deviation of at least one portion of the wafer with respect to the mask is measured and, on the basis of this measurement, the mask and the wafer are aligned with each other. After this,step-and-repeat exposure is executed. When the measurement of the positional deviation of the at least one portion of the wafer is unattainable, another portion of the wafer is selected and the deviation measurement is executed in respect to the selected portion. In another aspect of the invention, with regard to a rotational component of the deviation of the wafer, measurement and alignment are repeatedly executed until the rotational component becomes less than a predetermined value. Thereafter, the step-and-repeat exposure is initiated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.