Key Technologies Of Airshowering With Constant Temperature For Ultra-precision Equipment

Ultra-precision machining and measuring equipment that the step and scanlithography represents plays its important role in the modern industry production andscientific research. As the core equipment of large-scale integrated circuitmanufacturing, lithography has a high degree of technique integration whose movingparts’ positioning accuracy represented by linear motor’s and voice coil motor andmeasuring devices’ measuring accuracy represented by laser interferometer are bothreaching namoscale. Meanwhile, those accuracy is sensitive to environment parameterespecially the temperature, which results that the lithography needs environmentcontroller to guarantee its nanoscale accuracy. Meanwhile, ultra-precision measuringequipment which represented by Nano-CMM (coordinate measuring machine) has acertain requirment of the control of external and internal environment because of itsnanoscale measuring accuracy in the field of ultra-precision measurment.As is stated above, the project "key technologies of airshowering with constanttemperature for ultra-precision equipment" developed a airshower unit with highprecision whitch can be used to stabilize optical path or control lens elements andassembly parts of laser interferometer. This article divides the system into two parts:theAir processing module and the airshower module with constant temperatyer. The maincontributions are as follows:First of all, the interference factors from environment which are harmful to thestability of interference beam are analysed, and it is confirmed that the temperature isthe main cause during the environment parameter that changes the refracvive index ofair. Moreover, the functional modules that mainly contains heater and cooler units aredesigned to reduce the diviation from temperature, and its parameters are calculated.Then, a project named airshower with constant temperature system is preposed whosecores are high precision constant temperature air processing module and airshower flowequalize module based on multi-layer plate structure; Based on that, the strategy andalgorithm of temperature control are analysed and finally selected the strategy that theheater unit and cooler unit work together which can offset the thermal inertia fromheater and cooler and produce a high temperature control accuracy. Besides, the PIDalgorithm is selected to be the closed loop control method of the airshowering with constant temperature system.According to the airshwoering with constant temperature system project, a airprocessing module with high accuracy is designed which mainly contains fan, heatexchanger, heater and so on, and the resolution of cooler control is0.004°C, that ofheater control is0.019°C. Furthermore, the airshower flow equalize module based onmulti-layer plate structure is designed and proceed which has a wedge cavity structureto realize the well-distributed airshowering. At last, the airshower sturcter is analysedwith the software called ANSYS.At last, this article builds an experimental platform for airshowering with constanttemperature system, and finished the debugging and function index verification whichshows that the project of airshowering with constant temperature system that this articledesigned has reached the predetermined target.