Apparatus for projecting a series of images onto dies of a semiconductor wafer
US4444492A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 29, 1982 |
| Grant date | Apr 24, 1984 |
| Priority date | — |
| Expiry date | Jul 29, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/70
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The apparatus forms one-to-one reticle images on a wafer. The apparatus includes means for holding a reticle containing an image pattern corresponding to the size of the desired wafer pattern. An illumination system substantially uniformly illuminates the reticle pattern. A one-to-one stationary projection optical system projects an image of the reticle pattern onto a predetermined focal plane. Suitable means such as a vacuum chuck holds the wafer. An alignment system steps and orients a wafer chuck to register markings on the individual sides of the wafer with the projected image of corresponding markings on the reticle. A fluid servo system acts on the chuck to hold at least a portion of the wafer in the predetermined focal plane of the projection optical system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.