Method for detecting adjustment error in photolithographic stepping printer
US6245584A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 1, 1999 |
| Grant date | Jun 12, 2001 |
| Priority date | — |
| Expiry date | Jul 1, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/34
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An adjustment error in a photolithographic stepping printer 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 (16) 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. An adjustment error is determined to exist if the visible images appear substantially identical but are uneven or otherwise abnormal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.