【作者】 王勇；

【导师】 孙玉利；

【作者基本信息】 南京航空航天大学 ， 机械制造及其自动化， 2017， 硕士

【摘要】 锗是重要的半导体材料,具有优越的物理化学性能,不仅应用于半导体产业,还在红外光学、太阳能电池、化学催化剂以及生物医学等领域有着广泛的应用。而作为太阳能电池衬底用的锗单晶片,其形状精度、表面粗糙度、表面均匀性和加工效率都有着更高的要求;同时,锗又属于脆性材料,实现超薄锗单晶片的高品质加工困难重重。本文结合低温抛光、固结磨料抛光与化学机械抛光技术,创新性地提出磨料均布的冰粒型固结磨具抛光锗单晶片的工艺方法。对冰粒型固结磨具抛光锗单晶片的抛光温度场、相对速度场、应力场以及加工工艺展开了研究,主要的工作和成果如下:1.利用ABAQUS软件建立了抛光盘温度场有限元分析模型,获得了冰粒型固结磨具在不同抛光时刻的温度场云图及融化厚度值,并通过测温装置验证了模型的结果;利用建立的有限元模型,分析了抛光时间、冰盘初始温度、环境温度、气缸压力和抛光盘转速对温度场变化的影响。2.对精密抛光系统进行了受力分析,探究了提高工件转速的方法;分析了转速比与偏心距对速度分布的影响;采用有限元分析法研究了加载方式、环境温度、气缸压力、承载器厚度对抛光应力场分布的影响;控制了浮动抛光后工件面型的变化。3.开展了冰粒型固结磨具抛光锗单晶片的工艺研究,分析了H2O2在冰盘抛光过程中的作用;优化分析了环境温度、抛光盘转速、抛光时间和气缸压力对粗抛时的材料去除率和精抛时表面粗糙度的影响,获得了优化的工艺参数。更多还原

【Abstract】 As an important semiconductor material,germanium has excellent physical and chemical properties.In addition to the semiconductor industry,the germanium has a wide range of applications in the field of infrared optics,solar cells,chemical catalysts,biomedical field and others.As a single crystal germanium wafer for solar cell substrate,its shape accuracy,surface roughness,surface uniformity and processing efficiency have a higher demand.At the same time,the germanium belongs to brittle material.It is very difficult in achieving high-quality processing of ultra-thin single crystal germanium wafer.In this thesis,combined with low temperature polishing,fixed abrasive polishing and chemical mechanical polishing technology,a new method of ice-fixed abrasive polishing was proposed to polish single crystal germanium wafer.The polishing temperature field,the relative velocity field,the stress field and the processing technology were studied.The main work and achievements are as follows:1.A finite element analysis(FEA)model was established by ABAQUS software.The temperature field and melting thickness of ice-fixed abrasive polishing tools were obtained at different polishing times.The results of the model were validated by temperature measurement device.The effects of polishing time,initial temperature of ice tray,ambient temperature,cylinder pressure and rotational speed of ice tray on the temperature field were analyzed by using the established finite element model.2.The force analysis of the precision polishing system was carried out,and the method to improve the speed of workpiece was discussed.The influences of speed ratio and eccentricity on relative velocity distribution were analyzed.The stress field distribution of the load mode,ambient temperature,cylinder pressure and thickness of the carrier were studied by finite element analysis.The variation of the workpiece surface after polishing was controlled.3.The study on the processing technology of polishing single crystal germanium wafer with icefixed abrasive polishing tool was carried out.The effect of H2O2 on the polishing process was analyzed.The influences of ambient temperature,rotational speed of ice tray,cylinder pressure and polishing time on material removal rate during rough polishing were analyzed and optimized and the influences of them on surface roughness during fine polishing were analyzed and optimized.The optimized process parameters were obtained.更多还原