Method for transferring pattern images through mix-and-match exposure at improved overlay accuracy
US6027839A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 16, 1998 |
| Grant date | Feb 22, 2000 |
| Priority date | — |
| Expiry date | Nov 16, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70475
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A scanning reduction projection aligner has an image field twice wider than an image field of a stepping reduction production aligner, and plural first latent images and plural second latent images are formed in a first photo resist layer and a second photo resist layer spread over a semiconductor wafer in different phases of a fabrication process of a semiconductor device by using the stepping reduction projection aligner and the scanning reduction projection aligner, respectively; when the first latent images are formed in the first photo resist layer, narrow areas of the first photo resist layer are aligned with a reticle by using an alignment mark on the semiconductor wafer at every other pattern transfer so that each second latent image is exactly superimposed on one of the pairs of first latent images in spite of incorrect perpendicularity of orthogonal coordinates virtually determined over the semiconductor wafer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.