Precision IC alignment keys and method
US4523851A · kind A · utility
2Cited by
5References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 11, 1982 |
| Grant date | Jun 18, 1985 |
| Priority date | — |
| Expiry date | Aug 11, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7076
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Various structural patterns of alignment keys particularly suited for aligning masks and wafers during the fabrication of semiconductor devices. Each alignment key includes an orthogonal arrangement of bar-shaped segments. The relative dimensions of the mask and wafer alignment keys ensure a partial overlap and coaxial positioning of the bar-shaped segments when the keys are fully aligned. Precise optical alignment of the mask and wafer keys is evidenced by visually perceived edge diffraction effects. The invention also encompasses a systematic method for aligning representative structural patterns.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.