Autofocusing system for spatial light modulator-based maskless lithography
Abstract
To produce diffractive or holographic structures in a photolithographic process, an optical projection system enabling structure resolution in the submicrometer range is highly desirable. To ensure that the optical focus of such a system lies on the substrate surface during the whole lithographic fabrication process, an autofocus system able to focus on a depth of field of a few hundred nanometers is usually required. In this work, we developed an autofocus system for spatial light modulator (SLM)-based maskless photolithographic applications. The system is capable of high-precision focusing without affecting the photoresist performance. It is based on contrast measurement combined with focus-pattern illumination to ensure high contrast at the substrate surface. In addition, we evaluated various autofocus algorithms with respect to time efficiency and accuracy to determine suitable focus-pattern and focus-algorithm combinations.
Details
- Organisation(s)
-
Hannover Centre for Optical Technologies (HOT)
- Type
- Article
- Journal
- Applied optics
- Volume
- 55
- Pages
- 1863-1870
- No. of pages
- 8
- ISSN
- 1559-128X
- Publication date
- 08.03.2016
- Publication status
- Published
- Peer reviewed
- Yes
- ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics, Engineering (miscellaneous), Electrical and Electronic Engineering
- Electronic version(s)
-
https://doi.org/10.1364/AO.55.001863 (Access:
Closed
)
