Development Of The Dual-beam Micro Cutting Method And Apparatus

Laser cutting has a wide range of applications in large-scale industrial production and precision machining. How to improve the quality of laser cutting has always been an important issue in the field of laser processing. When using conventional laser cutting method to process a wafer, the material removal mechanism of laser cutting makes it difficult to completely eliminate the heat affected zone. Large heat affected zone will seriously affect the performance of the chip.In this thesis, how to improve the cutting quality of 355 nm laser cutting wafers and other fragile materials is studied. The idea that it is possible to reduce the laser cutting thermal stress and the heat-affected zone by isolating the thermal conduction in order to improve cutting quality is proposed. From this idea, the traditional cutting method is analyzed. A new method of laser cutting which is called dual-beam micro cutting method is proposed. Based on the engineering thought, a set of devices are designed to implement this method. When the apparatus is actually applied to cut the wafer, it can effectively improve the quality of laser cutting and reduce the width of the slit. I believe that the apparatus will be widely used in the production in the near future.Innovative work done by this article is followed:(1) Put forward that it is possible to barrier the heat transfer to the both sides of the slit when formal cutting, to reduce the heat affected zone and cutting heat stress by drawing symmetrical and parallel grooves on both sides of the pre-processing position. Thereby the kerf is narrower, and the cutting quality is improved.(2) Two technical solutions that are able to achieve this cutting method are put forward. Then, the technical solutions are analyzed and compared. The overall design of the laser cutting apparatus based on this method is completed.(3) The problems that are required to be solved are analyzed. The selection of the device's core components( laser, translation stages and their controller, the focusing lens) is completed. Focused beam characteristics are analyzed. Assembly structure of each component of the cutting device is designed.(4) Dual-beam macro trimming cutting device is optimized. The focus and align the focal position features are added for the apparatus by using familiar devices. A software is developed for focusing function, in order to further improve the reliability of the device.