Research On Crack-free Glass Micro-groove Processed By 248nm Excimer Laser

The hard and brittle material glass is the ideal base material for microfluidic chip,but it is a big problem to process it with high quality and efficiency.The 248nm ns pulse excimer laser has many advantages,such as short wavelength,high single pulse energy,stable laser performance,so the mechanism and technical process for crack-free glass etched by 248nm ns laser is researched in this study,which is of a great importance to gain the glass microfluidic chip manufacture technology with good structure quality and high efficiency.In this study,the mechanism and the regularity of crack damage technical for two different glass materials processed by the 248nm ns excimer laser is studied through the experiment,by optimizing the laser processing technology,the processing target of low crack and crack-free micro-groove in the glass surface are realized.The specific research contents and results are as follows:1.The research on mechanism of 248nm ns excimer laser etching the soda lime glass and quartz glass:With the phenomenon of laser etching and the morphology of glass etched by the laser are analyzed,the results showed that the mechanism of 248nm ns excimer laser etching soda lime glass is micro-crack-etching,and the mechanism of etching quartz glass has combined the faction of photo ionization and thermal ablation,so it can be achieved crack-free.2.The research on low crack damage soda-lime glass micro-groove etched by248nm ns excimer laser:it is mainly studied that the characteristics of the glass cracks are influenced by laser parameters and the status of the material surface,the research results show that as the laser fluence is increasing,the degree of the micro-groove edge crack and the roughness of the etched glass microstructure surface will be also increased;The threshold of laser etching glass material can be reduced on the rough surface,so the lower the laser energy density can enhance the surface quality after machining.As process improvement,the crack size of the soda-lime glass micro-groove edge is less than 5?m,and the Ra of bottom surface roughness can be reduced to 1.5?m,so the processing quality is improved.3.The research on crack-free of quartz glass micro-groove etched by 248nm ns excimer laser:The factors of causing quartz glass crack are explored,the results show that the laser fluence is the main causes to cause the quartz glass crack,and it is concluded that the laser fluence threshold range of crack-free etching the JGS1 quartz glass is 16J/cm~2~30J/cm~2,the etching rate is up to 500 nm/pulse;and there are some factors to increase the crack,such as the uneven distribution of the laser fluence,high laser frequency,more material surface defects and the deviation for scanning trajectory.As the laser processing parameters improved,when the micro-groove width is less than100?m,the straight(depth less than 50 microns or)and the circular arc(depth of28.5?m)crack-free quartz glass micro-groove can be achieved.4.A method to measurement the transparent plate thickness based on the laser triangulation with light refraction compensation is put forward,and a set of transparent plate thickness measurement device is designed.Finally,it is applied to the calibration of the image plane when transparent material is processed by the laser projection lithography,the absolute error of the measurement device is less than 0.01 mm,so it can be meet the accuracy of excimer laser processing microfluidic chip.5.Based on the MPC2810A controller and the software environment of Visual C++6.0,the control software for the excimer laser micromachining system is designed,it have many functions,such as the programming instructions for multi-step continuous movement,simulation for movement trajectory,real-time display for movement parameter and trigger for laser,etc.