Method of detecting positional deviation
US5114235A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 17, 1990 |
| Grant date | May 19, 1992 |
| Priority date | — |
| Expiry date | Jul 17, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7049
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of detecting relative positional deviation of first and second substrates, wherein first and second marks with optical powers are formed on the first and second substrates. A radiation beam is projected to the first substrate and, as a result, the first and second marks produce a signal beam whose position of incidence upon a predetermined plane is changeable with the relative positional deviation of the first and second substrates. A sensor is disposed adjacent to the predetermined plane and receives the signal beam to produce an output signal corresponding to the position of incidence of the signal beam upon the sensor. Here, a reference mark is provided to produce, when irradiated with a radiation beam, a reference beam so that it advances along a light path substantially the same as the light path for the signal beam to the sensor when the first and second substrates are in a predetermined positional relation. The produced reference beam is received by the sensor, whereby a reference signal corresponding to the position of incidence of the reference beam upon the sensor is obtained. The relative position of the first and second substrates can be detected on the basis o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.