【作者】 黄海苟；

【导师】 田昭武；

【作者基本信息】 厦门大学 ， 物理化学， 2001， 硕士

【摘要】 微／纳米科学技术作为二十一世纪的关键高新技术之一，将导致人类认识和改造世界能力的重大突破。而具有强烈交叉学科色彩的微系统(或微机电系统，MEMS)可能迅速崛起和蓬勃发展，成为微／纳米科技中的核心之一。为充分发挥微系统的功能和用途，需要制备较为复杂和高性能的微结构，因此必须发展和建立新型的加工技术。适宜于微系统的新型的加工技术应能满足如下三方面的要求：(1)能够加工复制出真正的超微复杂三维微加工图形或器件；(2)可批量生产；(3)达到微／纳米尺寸。 早在1992年，田昭武院士等就提出了约束刻蚀剂层技术(Confined EtchantLayer Technique，简称CELT)，是一种具有距离敏感性及控制保留量等特点，可用于三维超微(纳米)图形复制加工的新型技术，原则上它能同时满足上述三方面的要求，即可实现分辨率在微米、纳米级的复杂三维微细图形的复制加工。近十年来，我们实验小组不仅对CELT的相关理论问题进行了进一步探讨，并根据此原理对一些简单以及较为复杂的三维结构进行了加工刻蚀实验，表明CELT用于三维微结构加工刻蚀是可行的。但是该微结构是任意的，用规整模板复制加工更能体现CELT技术的优势。本论文基于此开展了下面的一些研究工作：一、 化学模板电极的制备 设计出微齿轮状、金字塔状等规整微图形，通过合作单位利用体硅工艺制成硅材料的模板。 通过射频溅射技术在Si基底模板上镀大约几百个纳米导电层(在镀Pt或 摘 要An之前，先镀几个纳米厚的Cr或Ti以增加镀层的牢固性）。实验发现，在以Br。作刻蚀剂的电化学刻蚀体系中，An镀层易被腐蚀破坏，而且会沉积到工件表面；所以在实验中，我们均采用Pt镀层。 通过射频溅射镀Pt膜的方法，让Pt膜作为连线，使棒与模板表面导通。在溅射镀膜时，模板的放置试用了两种方式：一种是模板表面与靶材表面平行，另一种是模板表面与靶材表面垂直。实验表明，后一种方式效果最好，既能使连接棒与模板表面导通，又不使模板表面的导电层沉积过厚。 采用恒电流方法，以模板作为工作电极，测试在不同电流密度下模板的使用寿命。结果发现，在电流密度小于1．OX10－‘A／Cof时，模板可以进行20次以上刻蚀实验；电流密度远大于 1．0 X 10W Cmz时，模板表面的镀层 Pt，12次实验后就脱落。 通过逐渐优化制作过程，摸索出一条较为成熟电化学模板的制作工艺。二．用规则模板对半导体GaAs的加工刻蚀1．齿状模板对GaAS的加工刻蚀 用同一模板在GatS表面刻蚀出的两个图形，被刻蚀出的是模板的负像。其上的十字状结构及中间的齿状微结构都非常相似。说明CELT技术可以进行批量复制。样品GaAS表面的九条凹槽与模板图形互补，实现了模板立体微结构图形的复制。2．金字塔状阵列模板对GaAS的加工刻蚀 GaAs样品表面被刻蚀出一规整微孔组成的阵列。微孔深度在 1．ffel．8 11m之间。两相邻微孔最低点间的距离为14．9 P m，与模板上两相邻“金字塔”状锥体最高点间的距离 15．4 11m基本吻合。通过比较计算得到实验加工精度大约在 1卜m左右。同时分析了样品表面图形的形状与原模板的负像相比发生了变化伯由方锥孔变为圆锥孔）的原因。 n 摘 要三．CELT技术用于抛光刻蚀 以抛光微圆盘电极作模板对粗糙的GaAS表面进行平整，获得了表面粗糙度更小的平整表面，显示了CELT技术作为一种平面抛光手段的潜力。更多还原

【Abstract】 Micro- and Nanometer science and technology, which will lead to a great breakthrough in understanding and transforming the world is considered to be a key Hi-tech in 21st century. The micro system or microelectromechanical systems (MEMS), as an interdisciplinary field, will be a core of micro- and nanometer science and technology. In order to exert the potential of MIEMS, a new micromachining method that is capable of generating complex and high performance microstructures must be further developed. The method that is suitable for microfabrication should meet the following three requirements: (1) capable of replication of real complex ultramicro-patters and units; (2) capable of mass product; (3) producing units in the micro/nano-meter scale. The Confined Etchant Layer Technique (CELT) as a new approach of electrochemical three-dimensional micromachining was proposed by Prof Zhao-Wu Tian in 1992.This method is distance sensitive and controls the quantity of survival (in comparison with the current micromachining techniques, which control the quantity of removal), which makes the replication of ultramicro three dimensional patterns possible. In the recent ten years, the further analysis on the CELT theory was done and microfabrication experiments were performed with simple micro-disk electrode and spherical platinum electrode, the results show the method is feasible in fabricating three-dimensional micro-pattern. However, in previous study, the selection of the micro-pattern was arbitrary. Three-dimensional microfabrication using regular pattern mold will outstand the advantage of CELT. The results of present work are described as followed 1. Preparation of electrochemical molds Molds with regular microstructures were fabricated by bulk silicon etching technique on silicon wafers. As the electrochemical mold must have excellent conductance, a Cr or Ti film with thickness of several nanometers was sputtered as adhesion layer before a Pt film with thickness of several hundreds nanometer was deposited on the mold surface .The conductive connector between the mold surface and the lead was also a sputtered Pt film along the side of the silicon after the mold was fixed at the tip of a metal stick. In order to test the lifetime of the electrochemical mold, the etching process was performed using it as the working electrode at different constant currents. It was found that the electrochemical mold could be used for more than 20 times when the current density i is lower than 1.0 X 102k1 cm2 ; However, when the current density was much higher than 1.0 X 10 A/ cm , the sputtered Pt film would be fallen off only after 1-2 experiments 2. Fabrication of GaAs with regular patterns molds Two etched patterns resembled each other were obtained with the same gear-like mold. The etched pattern has nine slots and eight protruding lines, compared with the mold, it is almost the negative copy of the mold. The etched microhole arrays were obtained on a GaAs surface. The depth of the holes varies from 1.61?m to 1.81?m. The distance between the bottom point of the two nearest holes is 14.9 t~?m which is in agreement with that of 15.4 ii m between the highest point of two adjacent pyramids. The precision of the etching in this experiment was ca. I ii in. The reason for the transformation of the shape from pyramid for mold to cone for the workpiece was discussed. 3 .Polisbing surface of semiconductors with CELT更多还原