ساخت دستگاه و ارائه روش ميكروماشينكاري فتوشيميايي بدون ماسك با استفاده از ليزر

چكيده انگليسي :

Manufacturing and Utilization of a Maskless Laser Lithography System for Photochemical Machining Mohammad Jamali Ghahderijani m jamali@me iut ac ir Date of Submission 2012 03 6 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisors Alireza Fadaei Tehrani mcjaft@cc iut ac ir Hamid Reza Mirdamadi hrmirdamadi@cc iut ac irAbstract Photochemical machining is a non traditional machining process that can be applied to most metallicand several non metallic substances and due to elimination of mechanical stresses the produced surfacesare burr free and rough down to a few nanometers without any excessive polishing process The mostimportant step of this technique is optically applying desired pattern on photoresist which is calledlithography Lithography process is employed to cover selected areas with a photosensitive polymer and letthe uncovered areas to be removed or processed in subsequent steps Lithography as the most important andchallenging step is done in several ways which are divided into two major types mask based and maskless Conventional lithography mask based uses light that shines through the entire surface of a mask at once Itrequires exorbitant and massive optical and precision setting elements besides the complexity of designinga photomask Maskless lithography is done through incremental exposure of a substrate without using anymasks Its primary use is in rapid prototyping small scale manufacturing non planar lithography andfabrication of photomask for mask based lithography Maskless laser lithography is one of the numerousmaskless systems that have been developed in recent years through rapid development of solid state andsemiconductor lasers with shorter wavelengths that are highly affordable and energy efficient In masklesslaser lithography exposure time would be less than a micro second using a focused high power laser beam Covering the whole workpiece surface by moving laser on workpiece or vice versa completes the exposureprocess Maskless laser lithography is capable of reaching feature sizes down to few hundreds ofnanometers Moreover maskless laser lithography is well suited for lithography on non planar surfaces Incurrent research the development and manufacturing of a maskless laser lithography system is introduced The system uses components that are commercially available and highly affordable for such a system incomparison to other available lithography systems The system uses a semiconductor laser extracted from ablu ray burner drive The optical components were also were readily available from the drive This laser isdriven by a iC NZN laser driver board in current control mode The laser and the stage that holds theworkpiece are moved using two stepper motors that rotate a screw to give precise movement speed Adriver has been designed for steppers that can supply voltages down to five volts with a soft micro steppingfunction The whole system is controlled using an FPGA board that is programmed with Verilog language This system was utilized to produce some micro channels as a useful product and to evaluate systemparameters The minimum channel width that could be reached using this system and the commerciallyavailable Positive 20 photoresist was about five micrometers Finally the system parameters and output areanalyzed In order to do that mixed factorial design of experiment is used The results were analyzed usingANOVA to find main effects and interactions of laser power scanning speed and photoresist thickness onmicro channel width Moreover those parameters were used to find the best regression model to find aformula that connects those parameters with micro channel width Keywords photochemical machining laser maskless micro channel

جمالي قهدريجاني، محمد

ساخت دستگاه و ارائه روش ميكروماشينكاري فتوشيميايي بدون ماسك با استفاده از ليزر

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