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Title:
POSITION DETECTOR AND FINE PATTERN FORMING SYSTEM EMPLOYING POSITION DETECTOR
Document Type and Number:
Japanese Patent JPH05144702
Kind Code:
A
Abstract:

PURPOSE: To achieve focusing without moving the optical element in a rear surface detecting optical system by optically correcting error due to shift of focus in a rear surface detecting optical system caused by fluctuation of the thickness of wafer.

CONSTITUTION: Focus of a rear surface position detecting optical system 27 shifts every time when the thickness of wafer 3 varies, and thereby focusing of a demagnification lens 22 onto the wafer 3 is performed through gap sensors 36, 23. The wafer 3 is mounted on XYZθ tables 28, 30, 31 being driven through a drive unit 33. Position of a reticle 19 is measured through a position detecting optical system 21 and a signal is delivered to a system control unit 37. Position of the wafer 3 is measured through the rear surface detecting optical system 27 and a signal is delivered to the system control unit 37. The system control unit 37 calculates relative positional shift and commands the XYZθ table drive unit 33 to move the wafer 3 to a desired position. Consequently, mechanical scanning is not required in the optical correction.


Inventors:
KATAGIRI SOUICHI
TERASAWA TSUNEO
Application Number:
JP30162391A
Publication Date:
June 11, 1993
Filing Date:
November 18, 1991
Export Citation:
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Assignee:
HITACHI LTD
International Classes:
G03F9/00; H01L21/027; H01L21/30; (IPC1-7): G03F9/00; H01L21/027
Attorney, Agent or Firm:
Ogawa Katsuo



 
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