Overlay mark for concurrently monitoring alignment accuracy, focus, leveling and astigmatism and method of application thereof
US6536130B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 2001 |
| Grant date | Mar 25, 2003 |
| Priority date | — |
| Expiry date | Nov 30, 2021 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S414/136
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An overlay mark for concurrently monitoring alignment accuracy, focus, leveling and astigmatism and a method of application thereof are disclosed. The overlay mark comprises four inner bars and four outer bars formed at the corners of exposure areas. The inner bar has a sawtooth area and a bar-shaped area, and the outer bar is a fore-layer etched pattern. Both the inner bars and the outer bars are formed into rectangles, and each bar is one side of a rectangle and none of the sides are connected. The sawtooth areas of the inner bars disposed on opposite sides are located at a same position. The rectangle formed by the outer bars encloses the rectangle formed by the inner bars. During the monitoring process, a testing beam scans across a scan area being divided into two areas, i.e., one being the outer bars and the sawtooth area of the inner bars, and the other one being the outer bars and the bar-shaped area of the inner bars.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.