Study On Fabricating Technology For Film Microstructure Based On Ultraviolet Nanosecond Laser Pulse

In recent years,the film structure has received extensive attention because its small feature size and unique properties in the aspects of light,electricity,magnetic,thermal and mechanical,which has more applications in the design of the key component such as the sensors,actuators,and resonators.At the same time,the application of the film structure also proposes higher demand for the laser fabricating technology which applies for the film structure.Therefore,the paper studies on the technology of the ultraviolet nanosecond laser pulse on the film structure.The work completed in the paper is as follows:(1)Analyze the interaction mechanism between the laser and material.Research the process of the laser reflection and absorption on the material.Use the dual temperature model to describe the process of the heat conduction of the pulsed laser inside the material.Deduce the relationship between the pulsed laser power and the spot diameter.Research the pulsed laser fabricating technology which applies to the film structure.(2)Optimize the ultraviolet pulsed nanosecond laser fabricating system.The motion control system is based on the motion control card called PMAC.PMAC sends the signal to the motor driver by the digital extensive card for the movement of the three dimensional stages.Optimize the mechanical structure of the optical path including the transmission,alignment and focus of the laser.Design the software of the upper computer based MFC and optimize the software with the multithread programming.(3)Study the position locating algorithm and the autofocus algorithm applying for the ultraviolet nanosecond laser aimed at the requirement of high precision of Z axis of the film structure.The position locating algorithm achieves the locating precision of 1 ?m by recognizing the bright area and combing with the gray weight method.The autofocus algorithm achieves the focus precision of 1 ?m by combing the imaging model of the object distance and the ratio of the gray values with Sobel gradient operator.(4)The experiments of the film structure are carried out by the optimized laserfabricating system.The experimental sample is the cooper film whose substrate is silicon and HgCdTe film whose substrate is Titanium alloy.The effect of the pulse repeat frequency,laser power and moving speed on the fabricating result is researched.The grating structure is fabricated on the copper film and the square structure is fabricated on the HgCdTe film,which both meets the demand of the fabricating.