Research Of On-line Measuring Equipment For Grinding Force Of Silicon Wafer Thinning

In the process of silicon wafer thinning, grinding forces not only influence production quality and efficiency directly, but also is an important indicator which shows wear conditions of grinding wheels and grinding vibration. The size and the tendency of real-time monitoring of the grinding force, combined with the production requirements of silicon wafer grinding, the grinding wheel speed, the feed rate, size and other parameters of the silicon wafer timely adjust, keep grinding state high quality in thinning in grinding process.According to the requirements in each step of silicon wafer thinning, combined with the structural characteristics of ultra-precision silicon wafer grinder with double-spindle and double-workstation, we develop an on-line measuring equipment for grinding force of silicon wafer thinning, based on the piezoelectric effect’s theory. The dynamometer utilizes4piezoelectric sensors arranged a square as electromechanical conversion elements, and is applied to measure and monitor simultaneously three orthogonal grinding forces in silicon wafer thinning. Besides, in theory, we analysis and calculate the stress characteristics and work principle of this dynamometer. According to the structure size and the work characteristics of grinder, referring dynamometer itself performance requirements, we design the shell structure of the dynamometer, and use ANSYS Workbench software to optimize the structure to select the optimal size. In addition, we discuss how the pre tightening force scheme of the dynamometer, and calculate the corresponding range of pre tightening force.Under experiment conditions, according to the installation of dynamometer on silicon wafer grinder, the static properties of dynamometer are experimentally tested in a special experiment table, such as the static calibration of center position, the static calibration of different position, the optimal selection of grinding area, the static calibration of grinding area. Establish dynamic calibration dynamometer experimental device, the dynamic properties of dynamometer are analyzed by using ball impact method. Finally, we make the actual grinding experiments on silicon wafer grinder, and verify the measurement performance of the grinding force measuring instrument. The experimental results show that the static and dynamic characteristics of the dynamometer has reached the national standard and the same type of dynamometers for the corresponding technical requirements, it provides reliable guarantee for the real-time online monitoring of three to control the grinding force and grinding technology of orthogonal silicon.