Liu Shi-yuan, Zhang Chuan-wei, Shen Hong-wei, Gu Hua-yong
State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2009 Apr;29(4):935-9.
A method and system for measuring deep trench structures of dynamic random access memory (DRAM) based on Fourier transform infrared (FTIR) reflectometry is proposed. The principle of the measurement system is presented, along with a detailed description of the optical path design. By regulating the slit aperture to decrease the size of the detection spot and optimizing the incidence angle onto the wafer, the reflection from the backside of the wafer is suppressed, thus the signal-to-noise ratio (SNR) of the measurement is increased significantly. The experiments carried out on the deep trench structures of DRAM demonstrate that the trench geometric parameters can be extracted with a nanometer scale accuracy using the proposed system, thus the technique is proven to provide a non-contact, nondestructive, time-effective, low-cost and high resolution tool for the measurement of deep trench structures. It is expected that the proposed technique will find potential applications in the on-line monitoring and process control for microelectronics and microelectromechanical system (MEMS) manufacturing.
提出了一种基于傅里叶变换红外（FTIR）反射测量法测量动态随机存取存储器（DRAM）深沟槽结构的方法和系统。介绍了测量系统的原理，并详细描述了光路设计。通过调节狭缝孔径以减小检测光斑的尺寸，并优化晶圆上的入射角，抑制了晶圆背面的反射，从而显著提高了测量的信噪比（SNR）。在DRAM深沟槽结构上进行的实验表明，使用所提出的系统可以以纳米级精度提取沟槽几何参数，因此该技术被证明可为深沟槽结构的测量提供一种非接触、无损、省时、低成本且高分辨率的工具。预计所提出的技术将在微电子和微机电系统（MEMS）制造的在线监测和过程控制中找到潜在应用。
