High-precision laser confocal measurement of semiconductor wafer thickness

被引：0

作者：

Li Z. ^{[1
]}

Liu Z. ^{[1
]}

Wang Y. ^{[1
]}

Qiu L. ^{[1
]}

Yang S. ^{[1
]}

机构：

[1] MIIT Key Laboratory of Complex-Field Intelligent Exploration, Beijing Institute of Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing

来源：

Guangxue Jingmi Gongcheng/Optics and Precision Engineering | 2024年 / 32卷 / 07期

关键词：

high precision; laser confocal; nondestructive measurement; semiconductor wafer; thickness measurement;

D O I：

10.37188/OPE.20243207.0956

中图分类号：

学科分类号：

摘要：

Addressing the need for precise non-contact measurement of semiconductor wafer thickness, this study introduces a method based on laser confocal technology that ensures remarkable accuracy. It utilizes a voice coil nanodisplacement platform for high-resolution actuation of a laser confocal optical probe, enabling precise axial scanning. This method relies on identifying the peak points on the confocal laser′s axial response curve, which are indicative of the objective lens′s focal point, to accurately align and position the wafer′s upper and lower surfaces. By accurately calculating the physical coordinates of each sampling point on the wafer surface through ray tracing algorithms, this technique achieves high-precision non-contact measurement of wafer thickness. A specialized laser confocal sensor for semiconductor wafer thickness measurement was developed, showcasing an axial resolution of under 5 nm, an axial scanning range of up to 5.7 mm, and repeatability in thickness measurement of under 100 nm across six wafer types. The process takes less than 400 ms for a single wafer. This research successfully applies confocal focusing technology to semiconductor measurement, offering a novel solution for high-precision, non-destructive, online wafer thickness measurement. © 2024 Chinese Academy of Sciences. All rights reserved.

引用

页码：956 / 965

页数：9

共 13 条

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