公开(公告)号：US09574992B1

公开(公告)日：2017-02-21

申请号：US15214814

申请日：2016-07-20

Applicant: KLA-Tencor Corporation

Inventor： Esen Salcin ,  Fuming Wang ,  Kevin Peterlinz ,  Hidong Kwak ,  Damon Kvamme ,  Uri Greenberg ,  Daniel R. Hennigan

IPC: G01J4/00 ,  G01N21/21 ,  G01J4/04

CPC classification number: G01N21/211 ,  G01B11/065 ,  G01B2210/56 ,  G01N21/9501

Abstract: Methods and systems for performing single wavelength ellipsometry (SWE) measurements with reduced measurement spot size are presented herein. In one aspect, a pupil stop is located at or near a pupil plane in the collection optical path to reduce sensitivity to target edge diffraction effects. In another aspect, a field stop is located at or near an image plane conjugate to the wafer plane in the collection optical path to reduce sensitivity to undesired optical-structural interactions. In another aspect, a linear polarizer acting on the input beam of the SWE system includes a thin, nanoparticle based polarizer element. The nanoparticle based polarizer element improves illumination beam quality and reduces astigmatism on the wafer plane. The pupil and field stops filter out unwanted light rays before reaching the detector. As a result, measurement spot size is reduced and tool-to-tool matching performance for small measurement targets is greatly enhanced.

Abstract translation: 本文介绍了用于执行单波长椭偏仪（SWE）测量的方法和系统，其测量点尺寸减小。 在一个方面，光瞳停止位于收集光路中的光瞳平面处或附近，以降低对目标边缘衍射效应的灵敏度。 在另一方面，场停止位于收集光路中与晶片平面共轭的图像平面附近或附近，以降低对不期望的光学 - 结构相互作用的灵敏度。 在另一方面，作用在SWE系统的输入光束上的线性偏振器包括薄的基于纳米颗粒的偏振器元件。 基于纳米颗粒的偏振器元件改善照明光束质量并减少晶片平面上的像散。 瞳孔和场域在到达检测器之前将不需要的光线过滤掉。 结果，测量点尺寸减小，并且大大提高了小测量目标的工具对工具匹配性能。