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1. (WO2017148322) DEVICE AND METHOD FOR MEASURING OVERLAY ERROR

Pub. No.:    WO/2017/148322    International Application No.:    PCT/CN2017/074508
Publication Date: Sat Sep 09 01:59:59 CEST 2017 International Filing Date: Fri Feb 24 00:59:59 CET 2017
IPC: G03F 9/00
G03F 7/20
Applicants: SHANGHAI MICRO ELECTRONICS EQUIPMENT (GROUP) CO., LTD.
上海微电子装备(集团)股份有限公司
Inventors: PENG, Bofang
彭博方
LU, Hailiang
陆海亮
WANG, Fan
王帆
Title: DEVICE AND METHOD FOR MEASURING OVERLAY ERROR
Abstract:
Disclosed is a device and method for measuring an overlay error. A measuring light adjustment assembly for adjusting measuring light to be centrosymmetric relative to the optical axis of a microobjective (46) is added to the device, so that the measuring light forms positive and negative level diffraction light by passing through this device and through an overlay measurement mark, and finally a diffraction spectrum of the positive and negative level diffraction light is displayed on a detector (411), wherein the spectrum of the positive level diffraction light and the negative level diffraction light on the diffraction spectrum are staggered to each other. A control system calculates an overlay error according to the diffraction spectrum, such that a broadband light source can be used during resource selection. Therefore, by means of this device and method, the wavelength range of measuring light is wider and any light spot-shaped light source can be used, such that the acquired measuring signals are more abundant, the precision of measurement is improved and the utilization rate of light energy is higher. A small-sized overlay measurement mark also can receive measuring light, and the device and method are also suitable for small-sized measured objects, thereby being better adapted to fine semiconductor products.