Method for detecting malfunction in photolithographic fabrication track
US6051348A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 17, 1999 |
| Grant date | Apr 18, 2000 |
| Priority date | — |
| Expiry date | Aug 17, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70616
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A malfunction in a photolithographic fabrication track is detected by applying photoresist to a semiconductor wafer, and exposing the wafer to substantially identical light images in multiple locations using a stepping printer. The light images are defined by an optical reticle and include a plurality of lines or other features that are spaced from each other at approximately the resolution limit of the printer. Developer is applied to the wafer to produce visible images corresponding to the light images. The visible images function as diffraction gratings which reflect light from the wafer. The visible images are inspected optoelectronically or manually. A malfunction is determined to exist if the visible images are not substantially identical.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.