Title:
OVERLAY MEASUREMENT DEVICE
Document Type and Number:
WIPO Patent Application WO/2021/049845
Kind Code:
A2
Abstract:
The present invention relates to an overlay measurement device. More particularly, the present invention relates to an overlay measurement device provided with an automatic focusing system using light sources of different wavelengths. The present invention provides an overlay measurement device for measuring an error between a first overlay mark and a second overlay mark respectively formed in different layers formed on a wafer, the overlay measurement device comprising: a first light source that emits a first beam; a first detector that acquires a signal from the first beam emitted from the first light source and reflected from a measurement position of the wafer; a second light source that emits a second beam having a wavelength different from that of the first beam; a second detector that acquires a signal from the second beam emitted from the second light source and reflected from the measurement position of the wafer; an objective lens that condenses the first beam and the second beam at the measurement position of the wafer, and collects the beams reflected from the measurement position; an actuator that adjusts the position of the objective lens relative to the wafer in the optical axis direction; a control means that controls the actuator; and a height detection means that detects the height of the first overlay mark on the basis of the change in the signal from the first detector according to the change in the position of the objective lens relative to the wafer in the optical axis direction, and detects the height of the second overlay mark on the basis of the change in the signal from the second detector according to the change in the position of the objective lens relative to the wafer in the optical axis direction.
Inventors:
PARK GYU NAM (KR)
SHIN HYEON GI (KR)
LEE SEUNG SOO (KR)
SHIN HYEON GI (KR)
LEE SEUNG SOO (KR)
Application Number:
PCT/KR2020/012096
Publication Date:
March 18, 2021
Filing Date:
September 08, 2020
Export Citation:
Assignee:
AUROS TECH INC (KR)
Attorney, Agent or Firm:
DYNE PATENT & LAW FIRM (KR)
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