基于声发射技术的CMP抛光机理分析及抛光状态在线监测理论方法研究

Chemical-mechanical-planarization (CMP) has become the very crucial technique of IC (Integrated Circuit) manufacturing, by which the grobal planarization of wafer can be achieved. With the development of IC industry, higher and higher polishing performance is required, and the rate of polishing defect need to be controlled further. Therefore, it is necessary to deeply research the CMP polishing mechanism and develop the techniques of on-line condition monitoring and defect detection during polishing process. Acoustic emission (AE) technique is becoming more and more attractive and has been applied successfully to the area of precise and ultra-prcise manufacturing. In addition, modal analysis method and the demage mechanics of material have been introduced into the area of AE technique, which makes it possible to research and explore the mechanism and characteristics of AE when the material removal of micro/nano scale occurs on the object. Therefore, in this project, AE technique is introduced into the area of the CMP technique to propose and develop AE technique based methods of polishing mechanism resaerch, on-line polishing condition monitoring, on-line performance monitoring and evaluation of polishing pad and on-line polishing defect detection.It could be expected that the implement and accomplishment of this project will not only promote the development of AE technique itself, but also develop an innovative and effective method for the research and the application of CMP technique.

化学机械抛光（CMP）是目前唯一能获得晶圆全局平坦化效果的加工方法并已成为IC制造领域至关重要的核心技术。而随着IC工业的发展，需进一步提高抛光质量和抛光效率并降低缺陷率，深入认识CMP抛光机理、对抛光过程和状态进行在线监测和检测显得越来越重要和必要。声发射技术已发展成为较成熟的技术并已在精密和超精密加工领域得到了成功应用，尤其是模态声发射技术的提出以及材料损伤力学研究成果的引入，使进一步探索材料表面微纳尺度材料去除过程的声发射机制成为了可能。本项目将声发射技术引入CMP抛光研究领域，对CMP抛光机理、晶圆表面材料去除机制、抛光垫性能演变和晶圆表面缺陷检测进行系统的理论探索和实验研究，发展基于声发射技术的CMP声发射技术的CMP抛光机理研究方法、抛光界面状态在线监测和抛光缺陷在线检测技术。这一研究不仅会促进声发射的发展，也为CMP抛光技术的研究提供一种新的有效方法和手段。

本项目将声发射技术引入化学机械抛光领域，研究典型材料微纳去除的声发射机制和化学机械抛光过程声发射特征和机制，探索化学机械抛光工艺参数以及抛光状态与声发射间的内在关系，发展基于声发射技术的化学机械抛光过程及状态检测、监测与分析方法，为化学机械抛光工艺开发和机理研究提供一有效手段和技术支持。主要研究内容和研究总结如下：1）设计并制备了专用抛光头，搭建了化学机械抛光过程及状态声发射检测、分析与监测系统，可实现抛光过程持续监测和在线分析；2）提出了基于遗传算法对小波尺度谱参数进行优化的方法，对比研究了三种谱峭度计算方法对瞬态成分的表征能力，获得了适合微纳材料去除声发射信号的分析方法；3）研究了典型塑性和脆性材料微纳去除声发射特征和声发射机制，发现了对于声发射塑性材料存在特征应变速率的规律，并建立了塑性变形的位错运动模型，揭示了应变速率对声发射信号的作用机理；获得了典型脆性材料的损伤特征以及相应的声发射时频特性；4）在上述研究基础上，研究了化学机械抛光工艺参数、抛光状态和抛光缺陷对声发射的影响，以及相应的声发射表征方法，获得了基于声发射的化学机械抛光过程、状态和抛光缺陷的检测、监测和分析的方法。这一研究不仅会促进声发射的发展，也为CMP抛光技术的研究提供一种新的有效方法和手段。