The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 24, 2014
Filed:
May. 04, 2012
Jinlong LI, Sichuan, CN;
Song HU, Sichuan, CN;
Lixin Zhao, Sichuan, CN;
Feng Xu, Sichuan, CN;
Lanlan LI, Sichuan, CN;
Zhuang Sheng, Sichuan, CN;
Jinlong Li, Sichuan, CN;
Song Hu, Sichuan, CN;
Lixin Zhao, Sichuan, CN;
Feng Xu, Sichuan, CN;
Lanlan Li, Sichuan, CN;
Zhuang Sheng, Sichuan, CN;
The Institute of Optics and Electronics, Sichaun, CN;
The Chinese Academy of Sciences, Sichuan, CN;
Abstract
Disclosed is a focus detection apparatus for a projection lithography system. The apparatus includes: a laser; a focus optical unit configured to focusing the emitted laser beam; a force detection unit configured to reflect the focused laser beam at the backside; a position detection unit configured to detect variations in position of a light spot formed by the reflected laser beam, and output a strength signal indicating the strength of the interaction force between the force detection unit and the object; a differential amplifier configured to output a Z-direction differential signal based on the strength signal and a reference signal; a Z-direction feedback control unit configured to perform feedback control; and a scan signal generator configured to output a signal for controlling the movement of the stage in the XY plane. The focus detection apparatus has high precision, efficiency and process applicability.