Experimental Study On Composite Processing Technology Of Picosecond Pulsed Laser For Monocrystalline Silicon

At present,the chips and microsensors in the main micro-function devices are all made of semiconductor materials.Among them,monocrystalline silicon is the most widely used.The continuous improvement and improvement of its processing technology has promoted a significant increase in the performance and indicators of integrated circuits.Lightweight,thin,short,and small have become synonymous with the semiconductor manufacturing industry.For the precision and micro processing of monocrystalline silicon,the traditional processing methods have been unable to meet the requirements due to the inherent physical properties and contact stress of the material,and the composite machining method based on ultra short pulse laser is becoming a hot topic in the research of monocrystalline silicon processing technology.The pulse width of the picosecond pulse laser is 10^-12s,the time of the energy action of the beam is very short,which is close to the time of the heat conduction of the monocrystalline silicon lattice.It can effectively reduce the heat influence range of the processing,improve the processing precision and obtain the better processing quality.The composite machining system constructed in this paper.the micropores of picosecond laser etching,picosecond laser and chemical etching,and microgrooves of picosecond laser and electrochemical are studied through the process experiments.the processing effects of these three methods are analyzed and compared.The main contents are as follows:?1?Theoretical research:The basic properties and electrochemical characteristics of single-crystal silicon materials are introduced.The chemical reaction and electrochemical reaction mechanism of silicon and sodium hydroxide solutions are analyzed.According to the effect of ultrashort pulse laser on the material,the thermal mechanism of picosecond laser and single crystal silicon is discussed;and the combination of picosecond laser irradiation and electrochemical reaction is further analyzed.For the precision and microfabrication mechanism of monocrystalline silicon,it provides theoretical guidance for subsequent processing experiments.?2?Test bench construction:Firstly,taking the laser and electrochemical machining system as an example,the characteristics of the laser and electrochemical composite processing were analyzed in depth.Four test systems built on the platform were elaborated in detail,and a test device for the composite etching processing system is constructed.Secondly,the galvanometric laser scanning system was introduced.With its high scanning speed and high precision,it provides favorable conditions for high efficiency and high quality machining.Finally,according to the quality requirements of the precision and microfabrication of single crystal silicon,as well as the characteristics of laser and electrochemical composite processing,the relevant testing equipment was selected,which provide the necessary conditions for process testing,results analysis and process optimization.?3?Experimental study:In the laser direct engraving test and in the laser and chemical etching composite machining test,the effect of laser power on the micropore characteristics was analyzed,and a comparative analysis was made on these two processing methods.This feature includes the diameter of the micropore the inlet,the exit,the taper and the morphology.In the laser and electrochemical composite processing experiments,the experimental phenomena were explained.The effect of the solution layer thickness on the depth of the micropore and the effect of the laser power on the microgroove processing quality were studied.Through the above theoretical analysis,test platform construction and experimental research.In terms of micro-hole processing,the composite processing technology overcomes the disadvantages of laser direct engraving and obtains a good processing appearance,demonstrating the superiority of the composite processing technology.In the micro-groove processing,the composite processing achieves a better inner wall morphology,but the bottom of the micro-groove processing results still need to be improved,indicating that the composite processing technology needs further in-depth exploration.In summary,ultrashort-pulse lasers and their composite processing technologies provide new technological approaches for the microfabrication of high-hard and brittle materials.