Research Of Purification And Temperature Control Technology For ArF Laser

ArF light source is one of the most critical components of projection lithography tool.There are only two companies who can provide ArF light source, one is in America andthe other one is in Japan. Projection lithography tool is not only the most criticalequipment in integrated circuits manufacturing, but also the one of main R&D tasks ofNational Science and Technology Major Project, and there are only three companies in theworld who are able to develop it. Purification technology and temperature controltechnology are the two key technologies of ArF light source. This thesis focused on theresearch of those two key technologies, provided appropriate technical solutions andcompleted an experimental verification of the solutions.In the ArF light source, purification unit and temperature control unit correspond tothe two key technologies. Purification unit controls chamber pollution, stabilizes theperformance of the optical system. By injecting purge gas into the chamber to from aslightly positive pressure to the external environment, purification unit is able to achievethe goal of chamber purification. Capillary is utilized to achieve slightly positive pressurecontrol. A capillary is placed at the inlet of the chamber, and a throttle is placed at theoutlet of the chamber. When the outside air pressure fluctuations, due capillary’s throttlingand pressure maintaining characteristics, the slightly positive pressure can be kept stable.The temperature control unit controls the temperature the chambers, maintains the opticalsystem’s performance. The plant cooling water is utilized in temperature control unit. Bycontrolling the switching valve, temperature control unit is able to control the averageflow rate of the cooling water, furthermore, to achieve temperature control of the chamber.In this thesis, the factors affecting the differential pressure of the chamber is analyzed,the relationship between the differential pressure change and the environment pressurechange is studied, the relationship between the differential pressure change and thecapillary’s structural parameters (inside diameter and length) is established, and therelationship between the differential pressure change and the outlet back pressure changeis analyzed. The effect of the cooling water temperature fluctuation on the chamber temperaturecontrol stability is studied, the chamber thermal load state changes of ArF light sourceunder working condition is analyzed, the transfer function of the temperature controlsystem is established, a PD fuzzy controller is designed and a control simulation iscompleted.Two experimental devices of the ArF light source purification unit and temperaturecontrol unit have been established. The experiments of slightly pressure purification andtemperature control have been conducted, which achieve slightly positive performance to20.3mBbar±1.1mBar/long-term, temperature control performance to22.05±0.2℃/5min22.05±0.3℃/long-term. Therefore, this thesis’s design of ArF light source purificationand temperature control technology has been proved feasible, and the technology will beused in the subsequent development of the domestic ArF light source.