In this study, an optical system for simultaneous measurement of physical thickness, group refractive index, bow, and warp of a large silicon wafer is first proposed based on a reflection-type spectral-domain interferometer. Such key parameters are determined by combining four different optical path differences (OPDs) measured at each sampling point throughout two-axis sample scanning within area of 250 mm by 250 mm. To overcome the measurement limitations by the deflection of a free, unclamped large-sized wafer, two OPDs representing the surface profiles of both sides are utilized to facilitate the thickness and refractive index measurements insensitive to sample inclination. For verification of the proposed method, a 300 mm diameter silicon wafer with nominal thickness of 775 μm was used as a test sample. For measuring the bow and warp with gravity effect compensation, a silicon wafer was measured once again after turning over. Through theoretical analysis on the changes of OP...

中文翻译：

---

使用光谱域干涉仪同时测量大型硅片的厚度，折射率，弯曲度和翘曲的新方法

在这项研究中，首先提出了一种基于反射型光谱域干涉仪同时测量大型硅晶片的物理厚度，组折射率，弯曲和翘曲的光学系统。通过组合在250 mm x 250 mm区域内的整个两轴样本扫描过程中在每个采样点测量的四个不同的光程差（OPD），可以确定此类关键参数。为了克服自由，未夹紧的大尺寸晶片的偏转而产生的测量限制，利用两个代表两侧表面轮廓的OPD来简化对样品倾斜度不敏感的厚度和折射率测量。为了验证所提出的方法，将标称厚度为775μm的直径300 mm的硅片用作测试样品。为了通过重力效应补偿来测量弯曲度和弯曲度，在翻转之后再次测量硅晶片。通过理论分析OP的变化