Process Modeling of Anisotropic Chemical Etching of Silicon

研究了单晶硅取向相关的各向异性刻蚀。名古屋大学的研究小组使用碱性溶液，如氢氧化钾（KOH）和四甲基氢氧化铵（TMAH）水溶液，测量了硅的蚀刻速率。他们评估了在温度和蚀刻剂浓度的广泛蚀刻条件下，许多晶体取向对蚀刻速率的取向依赖性。特文特大学和奈梅亨大学的研究小组试图用有限数量的物理参数来描述这种取向依赖性，这些参数过去用于晶体生长，即蚀刻的反向过程。他们引入了9个参数，并通过将这些值与名古屋大学提供的实验数据相拟合，他们成功地描述了使用KOH水溶液的一种蚀刻条件下的蚀刻速率，误差在5%以内。研究结果发表在两个国际会议上，并将发表在《传感器和致动器》杂志上：a .描述广泛蚀刻条件下的取向依赖是我们未来的工作，因为取向依赖在不同的条件下会有很大的变化。LAAS/CNRS课题组基于一个模型，利用蒙特卡罗方法在原子尺度上模拟了蚀刻过程，该模型考虑了硅背键随着硅表面原子上OH数量的增加而减弱。模拟的取向依赖性与名古屋大学测量的TMAH而不是KOH的实验结果相似，我们组织了一个关于硅各向异性刻蚀的研讨会。第一次研讨会于1998年在荷兰霍尔滕举行，并将于2000年在法国图卢兹举行。我们计划于2002年在日本举办第三届。

We investigated orientation-dependent anisotropic etching of single-crystal silicon. The group of Nagoya University measured etching rates of silicon using alkaline solutions such as potassium-hydroxide (KOH) and tetramethyl-ammonium-hydroxide (TMAH) water solutions. They evaluated the orientation dependence in the etching rate for a number of crystallographic orientations under wide ranges of etching conditions in temperature and etchant concentrations.The group of the Univ. of Twente and the Univ. of Nijmegen tried to describe such orientation dependence using a limited number of physical parameters, which used to be used in crystal growth that is the reverse process of etching. They introduced 9 parameters, and by fitting those values to experimental data provided from Nagoya Univ., they succeeded in describing etching rates within an error of 5% for one etching condition using KOH water solution. The results were presented in two international conferences, and will be published in Sensors and Actuators : A. It is our future work to describe orientation dependence for a wide range of etching conditions, because the orientation dependence significantly varies according to the conditions.The group of LAAS/CNRS simulated the etching process in atomic scale using Monte Carlo method based on a model, which considers weakening of silicon back-bonds according to the increase in the number of OH attached to the silicon surface-atom. The simulated orientation dependence was similar to that of the experimental results of TMAH rather than KOH both measured by Nagoya Univ.We organized a workshop focused on silicon anisotropic etching. The first workshop was held in 1998 in Holten, the Netherlands, and going to be held in 2000 in Toulouse, France. We are planning the third in 2002 in Japan.