超声椭圆振动辅助固结磨粒抛光硅片表面的机理研究

发布时间：2019-01-30 20:21

【摘要】：硅片是集成电路(Integrated Circuit,IC)最常用的基底材料,其表面质量的高低直接影响着IC芯片的性能。现代社会对IC的需求量不断增加,对其性能以及集成度要求越来越高,为增大IC芯片产量,降低器件的制造成本,硅片尺寸趋向大直径化;同时,IC集成度的不断增加,对硅片表面质量提出了更高的要求,即要求硅片表面越来越平坦、刻蚀线宽越来越细等,这些要求给硅片加工,尤其是抛光加工带来了很多困难。而传统游离磨料抛光硅片的加工方法普遍存在效率低、污染环境等问题,因此人们不断探索新的加工工艺,以适应大尺寸、高质量硅片表面的加工要求。固结磨料抛光工艺的应用很好地解决了传统游离磨料抛光过程中存在的材料去除率低、磨料浪费、污染环境和抛光质量不易控制等问题,又鉴于超声椭圆振动辅助加工具有提高加工效率、改善工件表面质量和延长刀具寿命等方面的优势,而被广泛应用于硬脆性材料的精密加工。基于这一背景,本文提出了超声椭圆振动辅助固结磨粒抛光硅片新技术,并开展了以下研究:首先,对抛光实验装置的主要构件及其抛光原理进行了介绍,并分析了抛光硅片表面形貌形成及材料去除与抛光运动过程;其次,为了更好地得出抛光硅片表面形貌及材料去除规律,提出了轨迹点密度这一概念及其仿真模型,进行了抛光硅片整个表面有无超声的对比仿真,并开展了相应的实验研究,结果表明硅片中心的材料去除量较多;最后,鉴于硅片表面的材料去除量非常小,对该值的测量非常困难,为了便于精确测量和更正确地反映抛光表面实际情况,开展了硅片表面圆环区域的实验与仿真验证研究,得到了抛光硅片表面粗糙度和材料去除量与进给速度、转速及抛光力之间的工艺规律,并得到如下结论:UFP抛光过程更稳定,更有利于抛光硅片表面粗糙度的减小和材料去除量的提高,所得结论可以为今后进一步的理论研究和实际生产提供参考。
[Abstract]:Silicon wafer is the most commonly used substrate material for integrated circuit (Integrated Circuit,IC), and its surface quality directly affects the performance of IC chip. In modern society, the demand for IC is increasing, and the demand for its performance and integration is becoming higher and higher. In order to increase the output of IC chips and reduce the manufacturing cost of devices, the size of silicon wafers tends to become larger in diameter. At the same time, with the increasing integration of IC, the surface quality of silicon wafer is required to be more and more flat, and the etching linewidth is becoming thinner and thinner. These requirements have brought a lot of difficulties to wafer processing, especially to polishing. However, the traditional free abrasive polishing silicon wafer processing methods generally have low efficiency, environmental pollution and other problems, so people are constantly exploring new processing technology to meet the needs of large size and high quality silicon wafer surface processing. The application of solidified abrasive polishing process has solved the problems such as low material removal rate, abrasive waste, environmental pollution and difficult control of polishing quality in traditional free abrasive polishing process. In view of the advantages of ultrasonic elliptical vibration aided machining, such as improving machining efficiency, improving workpiece surface quality and prolonging tool life, it is widely used in precision machining of hard brittle materials. Based on this background, a new technology of ultrasonic elliptical vibration assisted abrasive particle polishing silicon wafer is proposed, and the following researches are carried out: firstly, the main components and polishing principle of polishing experimental device are introduced. The formation of surface morphology, material removal and polishing motion of polished silicon wafer were analyzed. Secondly, in order to better obtain the surface morphology and material removal law of polished silicon wafer, the concept of trajectory point density and its simulation model are put forward, and the ultrasonic simulation of the whole surface of polished silicon wafer is carried out. The experimental results show that there is more material removal in the center of silicon wafer. Finally, in view of the very small amount of material removal on the wafer surface, it is very difficult to measure the value. In order to accurately measure and more accurately reflect the actual situation of the polished surface, the experimental and simulation research on the annular region of the wafer surface is carried out. The process rules between surface roughness, material removal amount and feed speed, rotation speed and polishing force of polished silicon wafer are obtained. The following conclusions are obtained: the polishing process of UFP is more stable. It is more favorable to decrease the surface roughness of polished silicon wafer and improve the material removal amount. The conclusions obtained can provide a reference for further theoretical research and practical production in the future.
【学位授予单位】：江西农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN405

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