US 11,656,391 B2
Aperture design and methods thereof
Hung-Chih Hsieh, Hsinchu (TW); Kai Wu, Hsinchu (TW); Yen-Liang Chen, Hsinchu County (TW); Kai-Hsiung Chen, New Taipei (TW); Po-Chung Cheng, Chiayi County (TW); and Chih-Ming Ke, Hsinchu (TW)
Assigned to TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Co., Ltd., Hsin-Chu (TW)
Filed on May 22, 2020, as Appl. No. 16/882,094.
Application 16/882,094 is a continuation of application No. 15/637,910, filed on Jun. 29, 2017, granted, now 10,663,633.
Prior Publication US 2020/0284954 A1, Sep. 10, 2020
This patent is subject to a terminal disclaimer.
Int. Cl. G03F 7/20 (2006.01); G02B 5/18 (2006.01); G02F 1/31 (2006.01); G03H 1/26 (2006.01); G03F 1/44 (2012.01)
CPC G02B 5/1866 (2013.01) [G02B 5/18 (2013.01); G02F 1/31 (2013.01); G03F 1/44 (2013.01); G03F 7/2024 (2013.01); G03F 7/70616 (2013.01); G03F 7/70633 (2013.01); G03H 1/26 (2013.01); G02B 5/1861 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method comprising:
using a first aperture plate to measure a first-axis diffraction of a composite grating, wherein the first aperture plate has a first pair of radiation-transmitting regions disposed along a first diametrical axis and on opposite sides of an optical axis; and
using a second aperture plate, complementary to the first aperture plate, to measure a second-axis diffraction of the composite grating, wherein the second aperture plate has a second pair of radiation-transmitting regions disposed along a second diametrical axis and on opposite sides of the optical axis, wherein the second diametrical axis is substantially perpendicular to the first diametrical axis, and wherein the first-axis is substantially perpendicular to the second-axis.