Novel nano-defect measurement method of SOI wafer using evanescent light
Novel nano-defect measurement method of SOI wafer using evanescent light
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DOI：
10.1117/12.630546
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发表时间：
2005-10
期刊：
影响因子：
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通讯作者：
R. Nakajima;T. Miyoshi;Y. Takaya
中科院分区：
文献类型：
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作者：
R. Nakajima;T. Miyoshi;Y. Takaya
为了实现现代半导体制造的高生产率和可靠性，SOI（绝缘体上硅）晶片层的缺陷检测技术变得更加重要。SOI晶片上的层只有100~ 200 nm的厚度，目前还没有合适的技术来评估这样薄的层中的缺陷。提出了一种利用倏逝场对SOI晶片层间纳米缺陷进行检测和分类的光学缺陷测量新方法。在该方法中，红外激光在涂层中传播时产生倏逝场，倏逝场受涂层表面及涂层下缺陷的影响。为了实现光耦合到该层中，研制了由单晶硅制成的棱镜耦合器。本文首先利用时域有限差分（FDTD）仿真工具对硅片表面附近的近场电磁场进行了分析。实验结果表明，该方法可以对表面和层内的纳米级缺陷进行检测和分类。其次，进行了聚焦离子束（FIB）加工SOI晶片上亚微米直径孔洞等缺陷的检测基础实验。实验结果也表明，该方法可以灵敏地检测出SOI晶片表面的缺陷。
In order to realize high productivity and reliability of the modern semiconductor fabrication, defects inspection techniques for the layers of SOI (Silicon On Insulator) wafer become more essential. The layers on SOI wafer have only about 100~200nm thickness, at present, the technique of evaluating appropriately the defects in such thin layers does not exist. Novel optical defect measurement method to detect and classify the nano-defects that exist in the layers of SOI wafers by using evanescent field is proposed. In this method, propagating infrared laser in the layer generates evanescent field, which is affected by the defects existing on and below the surface. To execute light coupling into the layer, the prism coupler that is made of single crystal silicon was developed. In this paper, first the electromagnetic field in near-field of the wafer surface vicinity was analyzed by using FDTD (Finite Difference Time Domain) simulation tool. The results show this method can detect and classify the nano-meter scale defects on the surface and in the layers. Next the fundamental experiment was carried out to detect defects like sub-micrometer diameter hole that was fabricated on SOI wafer using FIB (Focused Ion Beam) machining. The experimental result also shows this method can detect the defects on the surface of SOI wafers sensitively.