Research On The Distortion Of Single Crystal Germanium Wafer Polished With Ice-bonded Abrasives Effect Of Temperature Rising Rate Of After Treatment

Germanium has been widely used in the field of high technology for its excellent physical and chemical properties. The decrease of distortion is one of the most important part in the machining of single crystal germanium wafer. The quality of wafer which is machined by low-temperature polishing is high. However, the temperature rising process would lead to the distortion of wafer after the polishing machining. In this paper, the research on the distortion of single crystal germanium wafer in the effect of temperature rising rate was studied with the method of finite element simulation analysis. Besides, the effect of wafer geometric parameters, such as thickness and diameter, to wafer thermal distortion was also explored. A semiconductor temperature controlled tank was designed and produced. The simulation results were verified by actual experiments by using this tank.Research works in this paper are summarized as follows:1. By using ANSYS software, the research on the wafer distortion in the effect of temperature rising rate was explored. With the increase of temperature rising rate, the thermal stress got increased, which lead to obvious distortion. The thermal stress would increase and the distortion would get serious when the thickness became bigger. Though the diameters of thin wafers were different, the value and distribution of wafer temperature were almost the same.2. A semiconductor temperature controlled tank was designed and produced to control the rising rate of temperature. The shortest temperature rise time is 4 minutes and 49 seconds from-30? to 30?, and the adjustable range of rising rate was wide. The corresponding speed was less than 6s. The control precision was about 1?. The maximum temperature difference of the selected points about the same height was 0.35?, and the heat transfer was good. When the control voltages were same, the largest deviation of temperature rising time of different experiments was 2.33%, and the stability was good. The relationship of temperature rise time and control voltage was acquired with the method of fitting. The control voltages needed were got by this relationship, which were verified by experiments.3. The research on the wafer distortion in the effect of temperature rising rate was explored by experiments. The bigger the temperature rising rate was, the more serious the distortion was, which was consistent with the simulation result. The thicker the wafer w as, the less the distortion of wafer was in the temperature rising process. The smaller the wafer diameter was, the less the distortion of wafer was in the temperature rising process. The temperature rising process had a significant influence on the crack of wafer. The residual stress was changed during the temperature rising process, which means the distortion was caused by the combined action of the thermal stress and residual stress. The slip and multiplication of dislocation under the compound action of the thermal stress and residual stress was the fundamental reason for the wafer distortion.