Nano In-Process Measurement of 3D Micro-Profile Using Optical Inverse Scattering

使用光学逆散射对 3D 微观轮廓进行纳米过程测量

基本信息

批准号：
11555043
负责人：
MIYOSHI Takashi
金额：
$ 6.59万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11555043/
关键词：
Optical Inverse Scattering Phase retrieval 3D Micro-Profile Nano in-process measurement Fourier transform Fraunhofer diffraction Optical measurement レーザー応用計測

项目摘要

A new optical measurement method, which can be applied to in-process measurement of three-dimensional micro-profiles with accuracy in the nanometer order, is proposed in this paper. The proposed method is called optical inverse scattering phase method and offers the advantage of measuring a three-dimensional profile within the whole area illuminated by the laser beam simultaneously. This means that no scanning process is required. The optical inverse scattering phase method is based on two principles, one is optical Fourier transform, the other is iterative Fourier phase retrieval algorithm. Employing Fourier phase retrieval algorithm, three-dimensional micro-profiles are reconstructed from only the Fraunhofer diffraction intensity measured by Fourier transform optical system. Computer simulations as well as actual measurements were performed for the verification of our proposed method. First, the simulation results suggested the capability for reconstructing three-dimensional micro-profiles with accuracy in the nanometer order. As a strategy to avoid stagnation of iterative algorithm, a new concept based on the design model of the workpiece and the Gaussian profile of the laser beam was also proposed. Next, in order to verify the feasibility of the optical inverse scattering phase method, the automated optical measuring system consisting of Ar ion laser, Fourier transform lens, CCD linesensor, EWS computer, etc., was developed and the measurement experiments were carried out for the ultra-precision grid pattern with the depth of 44nm and the pitch of 10μm. The experimental results showed that the proposed method makes it possible to reconstruct a micro-profile within the whole illumination area equivalent to the laser beam diameter at one time without scanning.

本文提出了一种新的光学测量方法，该方法可以应用于以纳米顺序准确的三维微型原理的进程测量。所提出的方法称为光学逆散射相法，并具有在激光束轻松照明的整个区域内测量三维轮廓的优势。这意味着不需要扫描过程。光学逆散射相法是基于两个原理，一个是光学傅立叶变换，另一个是迭代傅立叶相检索算法。使用傅立叶相检索算法，仅从傅立叶衍射强度通过傅立叶变换光学系统测量的Fraunhofer衍射强度重建了三维微型原料。进行了计算机模拟以及实际测量，以验证我们提出的方法。首先，模拟结果表明，在纳米顺序中精确地重建三维微型原理的能力。为避免迭代算法停滞的策略，还提出了基于工作场所设计模型和激光束的高斯轮廓的新概念。接下来，为了验证光学反向散射阶段方法的可行性，开发了由AR离子激光器，傅立叶变换透镜，CCD线索，EWS计算机等组成的自动化光学测量系统，并为超强的网格模式进行了测量实验，并进行了测量实验，其深度为44nmnm and 44nnm and decters10μm。实验结果表明，所提出的方法使得可以在整个照明区域内重建一个微型构图，而无需扫描就可以一次与激光束直径重建。