Real-time autofocus for maskless lithography on substrates
US11067905B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 9, 2019 |
| Grant date | Jul 20, 2021 |
| Priority date | — |
| Expiry date | Apr 9, 2039 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7026
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Embodiments of the systems and methods discussed herein autofocus an imaging apparatus by pre-processing image data received via channels of the imaging system that include laser beams and sensors configured to receive image data when laser beams are applied across a substrate in a pixel-wise application across a substrate. The substrate can include both a photoresist and metallic material, and the images as-received by the sensors include noise from the metallic material. During pre-processing of the image data, a percentage of noise to remove from the image data is determined, and the image data is filtered. A centroid of the substrate is calculated for each channel and a focus deviation for the exposure is determined. The centroids can be combined using one or more filtering mechanisms, and the imaging system can be autofocused in an exposure position by moving the stage and/or the exposure source in one or more directions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.