Particle detection for patterned wafers of 100nm design rule by evanescent light illumination: analysis of evanescent light scattering using finite-difference time-domain (FDTD) method
Particle detection for patterned wafers of 100nm design rule by evanescent light illumination: analysis of evanescent light scattering using finite-difference time-domain (FDTD) method
复制标题
通过倏逝光照明对 100nm 设计规则的图案化晶圆进行颗粒检测：使用时域有限差分 (FDTD) 方法分析倏逝光散射
DOI：
10.1117/12.647933
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Y. Takaya
中科院分区：
文献类型：
--
作者：
T. Yoshioka;T. Miyoshi;Y. Takaya
为了实现半导体的高生产率和可靠性，保持高产量的图案化晶圆检测技术在现代半导体制造工艺中变得至关重要。由于电路特征尺寸小于100nm，传统的成像和光散射方法由于衍射极限和较低的信噪比而无法应用于图案化晶圆检测技术。因此，我们提出了一种使用环形倏逝光照明的新粒子检测方法。在该方法中，用作光源的会聚环形光入射到微半球形透镜上。当会聚角大于临界角时，半球透镜底面下方会产生环形倏逝光。倏逝光集中在底部表面附近，并在远离底部表面时呈指数衰减。因此，倏逝光选择性地照射图案化晶圆表面上的粒子，因为它不能照射图案化晶圆表面。所提出的方法通过检测颗粒的散射倏逝光分布来评估图案化晶圆表面上的颗粒。为了分析该方法的基本特征，使用FDTD方法进行了计算机仿真。仿真结果表明，该方法对于检测100nm线和间距的图案化晶圆上100nm尺寸的颗粒是有效的，特别是在p偏振且平行入射到线方向的倏逝光照射的条件下。最后，实验结果表明，可以检测到约200nm线和间距的图案化晶圆上的220nm尺寸的颗粒。
To realize high productivity and reliability of the semiconductor, patterned wafers inspection technology to maintain high yield becomes essential in modern semiconductor manufacturing processes. As circuit feature is scaled below 100nm, the conventional imaging and light scattering methods are impossible to apply to the patterned wafers inspection technique, because of diffraction limit and lower S/N ratio. So, we propose a new particle detection method using annular evanescent light illumination. In this method, a converging annular light used as a light source is incident on a micro-hemispherical lens. When the converging angle is larger than critical angle, annular evanescent light is generated under the bottom surface of the hemispherical lens. Evanescent light is localized near by the bottom surface and decays exponentially away from the bottom surface. So, the evanescent light selectively illuminates the particles on the patterned wafer surface, because it can't illuminate the patterned wafer surface. The proposed method evaluates particles on a patterned wafer surface by detecting scattered evanescent light distribution from particles. To analyze the fundamental characteristics of the proposed method, the computer simulation was performed using FDTD method. The simulation results show that the proposed method is effective for detecting 100nm size particle on patterned wafer of 100nm lines and spaces, particularly under the condition that the evanescent light illumination with p-polarization and parallel incident to the line orientation. Finally, the experiment results suggest that 220nm size particle on patterned wafer of about 200nm lines and spaces can be detected.