Auto-focusing of ultra-clean sample based on projection view method

Xing Liu; Guodong Chen; Jinlun Zheng; Jingsong Wei

doi:10.1117/12.2606335

1 November 2021 Auto-focusing of ultra-clean sample based on projection view method

Xing Liu, Guodong Chen, Jinlun Zheng, Jingsong Wei

Proceedings Volume 12057, Twelfth International Conference on Information Optics and Photonics; 1205738 (2021) https://doi.org/10.1117/12.2606335
Event: Twelfth International Conference on Information Optics and Photonics, 2021, Xi'an, China

Abstract

Auto-focusing methods, including infrared ranging, laser triangulation, ultrasound distance measurement, contrast detection, phase detection, depth from defocus, and depth from focus, are widely applied in laser direct writing system. Concurrently, the samples with an ultra-clean surface may cause the focusing to fail. This paper presents a method based on projection view to solve the auto-focusing problem of ultra-clean sample. A projection view in the Koller illumination path, is projected to the focal plane of the objective lens. One can, use the image of projection view in the charge coupled device (CCD) to evaluate the image definition so as to conduct a fast and accurate auto-focusing. A gray variance fusion model used for focusing accuracy evaluation is proposed. The robustness and accuracy of the auto-focusing are measured experimentally. The influencing factors including illumination condition and sample materials are analyzed. This method is useful for auto-focusing of ultra-clean samples.

Citation Download Citation

Xing Liu, Guodong Chen, Jinlun Zheng, and Jingsong Wei "Auto-focusing of ultra-clean sample based on projection view method", Proc. SPIE 12057, Twelfth International Conference on Information Optics and Photonics, 1205738 (1 November 2021); https://doi.org/10.1117/12.2606335

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
7 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Image analysis

Image fusion

Objectives

Error analysis

Image quality

Charge-coupled devices

Photoresist materials

Show All Keywords

Keywords/Phrases

Search In:

Publication Years