用于极紫外光刻非球面光学元件检测的复合三相位计算全息元件  

Triple Complex Phase Computer-Generated Holograms for Aspherical Surface Testing in Extreme Ultraviolet Lithography

作　　者：张海涛 谢常青[1] Zhang Haitao;Xie Changqing(State Key Lab of Fabrication Technologies for Integrated Circuits,Institute of Microelectronics of the Chinese Academy of Sciences,Beijing 100029,China;School of Integrated Circuits,University of Chinese Academy of Sciences,Beijing 100049,China;Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,Jilin,China)

机构地区：[1]中国科学院微电子研究所集成电路制造技术全国重点实验室,北京100029 [2]中国科学院大学集成电路学院,北京100049 [3]中国科学院长春光学精密机械与物理研究所,吉林长春130033

出　　处：《光学学报》2024年第14期119-125,共7页Acta Optica Sinica

基　　金：国家自然科学基金(62375281);应用光学国家重点实验室开放基金(SKLAO2021001A05)。

摘　　要：提出一种同时出射3个波前的复合三相位计算全息图(CGH),并将其应用于波前误差校正。通过6次组合测量标定出CGH基底制造误差和图形位置误差,并在检测结果中予以消除。所测试的极紫外光刻(EUVL)非球面光学元件峰谷(PV)值和均方根(RMS)误差分别为31.6 nm和4.88 nm。此外,对同一非球面光学元件进行基于折射零位补偿的检测实验,其PV值和RMS误差分别为38.6 nm和5.14 nm。所提出的复合三相位CGH具有实现亚纳米量级的EUVL非球面光学元件面形检测潜力。Objective Aspherical surface testing plays an important role in projection optics for extreme ultraviolet lithography(EUVL) systems and determines the resolution and overlay accuracy of the lithography system. The substrate transmission wavefront error and the pattern placement error are the main factors influencing the accuracy in the metrology of aspherical surface based on computer-generated hologram(CGH), which remains a great challenge to the traditional calibration methods. To this end, a new method for calibrating the wavefront error introduced by pattern placement error based on a triple complex phase is proposed and experimentally studied.Methods We propose a triple complex CGH that simultaneously emits three wavefronts for aspheric surface testing, and apply it to wavefront error calibration. By conducting six combined measurements, the manufacturing error and graphic position error of the CGH substrate can be calibrated, and they can also be eliminated in the measurement results. The first measurement is for interferometer TF and RF verification, and with the calibrating method, the surface form of TF and RF can be known. The second measurement is adopted for calibrating the first-order diffraction wavefront of CGH in the +X direction. The third measurement is employed for calibrating the first-order diffraction wavefront of CGH in the-X direction. The fourth measurement is for calibrating the first-order diffraction wavefront of CGH in the +Y direction. The fifth measurement is for calibrating the first-order diffraction wavefront of CGH in the-Y direction and the sixth measurement is to utilize TF and CGH for testing the aspheric surface.Results and Discussions Based on the measurement results of test 1-6, TF and RF surface form and tested aspheric surface form can be calculated. The peak-to-valley(PV) value of TF surface form is 74.2 nm and root mean square(RMS)error is 13.9 nm. The PV value of RF surface formform is 53.3 nm and RMS error is 6.6 nm. The PV value of surface form of the tested aspheri

关 键 词：测量 非球面 复合相位 计算全息图 组合测量 

分 类 号：O436[机械工程—光学工程]