Study On The Laser Induced Plasma In The Laser MicroMachining

The ability to fabricate micro and nano size channels and cavities will be important for the advancement of fluidic systems that are useful to improve performance and to add new function to applications such as chemical, blood, DNA, and environmental science analyses.There are two methods to fabricate micro channels: Using a Q-switched Nd: YAG laser (1.064μm, 100-200ns) The microchannel was fabricated by the thermal-induced process and the plasma-induced process, respectively, in quartz substrates. The plasma-induced process is using the higher energy of the plasma induced from quartz to drill hole on quartz through controlling the lifetime of the plasma.The length of the microchannel fabricated by plasma-induced process is not more than 4mm,which restrict the application in MEMS. This dissertation was started with the mechanism of induced plasma process, analysis the phenomenon of plasma induced by ND: YAG laser. The impact between the electromagnetic wave and the plasma was investigated because the laser is a wave, the plasma spectrum and plasma images was researched, at last, some rule of the electron temperature and the electron density was found, and obtain some available result.Based on the microwave technique about the plasma induced by microwave, It found the method to improve the lifetime of the plasma in the hole, so the length of channel using the plasma process is increase.In this dissertation, the laser-based micro and nano channel fabrication technique is fast and inexpensive, and will enable flexible fabrication of various kinds of 3-D micro fluidic systems and lead to new applications of MEMS in biomedical engineering.