Drilling of Microholes on Silicon Wafer With Ultrasonic Workpiece Holder

This paper presents a study to improve machining quality concerning the method of drilling ceramics and other hard and brittle materials such as silicon wafers. Instead of making the drill vibrate by the ultrasonic actuator, a new design of PZT-driving ultrasonic workpiece wafer holder is proposed to ensure the high quality, high efficiency and longer life for micro tools in drilling the silicon wafer. In this paper, ultrasonic workpiece holders are first designed by FEA and fabricated experimentally. Then, the ultrasonic holders is used for a series of experiments under different vibration conditions to examine the behavior of drilled hole accuracy, and edge chipping on the drilled hold surface. Also, the behavior of tool during ultrasonic vibration of holder is examined experimentally. The result demonstrates the ultrasonic workpiece holder could enhance the quality and efficiency for drilling silicon wafers.