行波超声振动抛光实验装置的研究

Research on Experimental Apparatus of Travelling Wave Ultrasonic Vibration Polishing

为研究环形行波压电振子的硅片超声复合抛光工艺,改装现有钻床,研制出一种可控转速的超声抛光实验装置,该装置主轴的转速通过变频器可在0～3 150r/min范围内调节,从而实现不同线速度的抛光需求。实验装置将USR30超声电机振子改造为具有装夹圆柄和抛光垫的抛光压电振子。改造后的振子的实际模态测试表明,装夹圆柄的安装并未改变原有超声电机振子的驱动频率。抛光实验过程中,抛光振子(含抛光垫)只做微观超声振动,而振子齿面下方的硅片做宏观的旋转运动,抛光垫与硅片之间注入一定流速的抛光液实现抛光。吸盘与动密封装置相联并通过主轴实现正(反)向旋转。为了研究压力对抛光表面质量的影响,该超声振动实验装置专门设计了重力加压装置,实现抛光振子与硅片之间的接触压力调节。该实验装置可完成改变抛光转速、抛光压力、抛光时振子表面振幅的大小及抛光液流量粒度等参数在不同工况下的抛光实验。

The existing drilling machine has been reassembled to the ultrasonic polishing experimental apparatus to research for the silicon wafer ultrasonic polishing process of ring traveling wave piezoelectric vibrator.And its revolving speed can be regulated from 0to 3 150r/min by frequency converter to meet the requirement of different linear velocity of polishing.During the experiment,the USR30ultrasonic motor vibrator has been changed to polishing piezoelectric vibrator with clamping handle and polishing pad.The testing results show that the driving frequency of the practical modes of the reformed vibrator with clamping handle was not changed.In the polishing experiment,polishing vibrator with polishing pad just ran with micro ultrasonic vibration,and silicon wafer under the teeth of vibrator ran with macro rotational movement.A certain velocity polishing slurries was put between them to finish the polishing.Vacuum sucker was connected to dynamic sealing,and it was clamped onto the principal axis,by which forward and reverse rotation can be realized.In order to study the influence of pressure on the polished surface quality, gravity pressure device was designed to change the contact pressure between vibrator and silicon wafer. The experimental apparatus can meet the requirement of experiment that changing the elements in different conditions which contents polishing speed,polishing pressure,amplitude of polishing vibrator and polishing slurries granularity parameter.