Zhang Zhenyu, Wang Bo, Zhou Ping, Guo Dongming, Kang Renke, Zhang Bi
Key Laboratory for Precision and Non-Traditional Machining Technology, Ministry of Education, Dalian University of Technology, Dalian 116024, China.
Changzhou Institute of Dalian University of Technology, Changzhou 213164, China.
Sci Rep. 2016 Mar 1;6:22466. doi: 10.1038/srep22466.
A novel approach of chemical mechanical polishing (CMP) is developed for mercury cadmium telluride (HgCdTe or MCT) semiconductors. Firstly, fixed-abrasive lapping is used to machine the MCT wafers, and the lapping solution is deionized water. Secondly, the MCT wafers are polished using the developed CMP slurry. The CMP slurry consists of mainly SiO2 nanospheres, H2O2, and malic and citric acids, which are different from previous CMP slurries, in which corrosive and toxic chemical reagents are usually employed. Finally, the polished MCT wafers are cleaned and dried by deionized water and compressed air, respectively. The novel approach of CMP is environment-friendly. Surface roughness Ra, and peak-to-valley (PV) values of 0.45, and 4.74 nm are achieved, respectively on MCT wafers after CMP. The first and second passivating processes are observed in electrochemical measurements on MCT wafers. The fundamental mechanisms of CMP are proposed according to the X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. Malic and citric acids dominate the first passivating process, and the CMP slurry governs the second process. Te(4+)3d peaks are absent after CMP induced by the developed CMP slurry, indicating the removing of oxidized films on MCT wafers, which is difficult to achieve using single H2O2 and malic and citric acids solutions.
一种用于碲镉汞（HgCdTe 或 MCT）半导体的化学机械抛光（CMP）新方法被开发出来。首先，采用固定磨料研磨加工 MCT 晶片，研磨液为去离子水。其次，使用所开发的 CMP 浆料对 MCT 晶片进行抛光。该 CMP 浆料主要由 SiO2 纳米球、H2O2 以及苹果酸和柠檬酸组成，这与以往通常使用腐蚀性和有毒化学试剂的 CMP 浆料不同。最后，分别用去离子水和压缩空气对抛光后的 MCT 晶片进行清洗和干燥。这种 CMP 新方法是环境友好型的。CMP 处理后的 MCT 晶片表面粗糙度 Ra 和峰谷（PV）值分别达到 0.45 和 4.74 纳米。在对 MCT 晶片的电化学测量中观察到了第一次和第二次钝化过程。根据 X 射线光电子能谱（XPS）和电化学测量结果提出了 CMP 的基本机制。苹果酸和柠檬酸主导第一次钝化过程，而 CMP 浆料控制第二次过程。所开发的 CMP 浆料诱导的 CMP 处理后，Te(4+)3d 峰消失，表明 MCT 晶片上的氧化膜被去除，这是使用单一 H2O2 以及苹果酸和柠檬酸溶液难以实现的。
