Supercritical fluid cleaning
The supercritical fluid cleaning equipment mainly uses the principle of supercritical CO2 extraction to realize the cleaning of semiconductor silicon wafers.
The semiconductor silicon wafers are placed in a supercritical CO2 fluid container (cleaning kettle), supercritical The CO2 fluid is used as a solvent to fully contact the semiconductor silicon wafer, and the soluble dirty substances dissolve and diffuse into the CO2 fluid, and then in a low-pressure container, the soluble dirty substances are precipitated to achieve the purpose of cleaning.
Our company was once commissioned by Taiwan Semiconductor Company to conduct a cleaning test, and the test results were approved by the commissioning party.
(1) It can meet the intermittent working conditions of supercritical carbon dioxide (Tc≥31.06℃, Pc≥9.39MPa), and the carbon dioxide can be recycled.
(2) A mixer is installed before the supercritical carbon dioxide fluid cleaning kettle to allow CO2 to be fully premixed with the co-solvent before entering the cleaner.
(3) A quick-opening observation hole is designed on the plug cover of the supercritical carbon dioxide fluid cleaning kettle for easy observation.
(4) On the pipeline after the supercritical carbon dioxide fluid cleans the kettle, the separation of gas, liquid, and slag is realized through the first and second filter separation devices, ensuring that the system pipeline is unblocked and not blocked.
(5) Carbon dioxide primary and secondary separation devices are designed with water jackets and external insulation devices, and two sets of constant temperature water baths and low-temperature cooling liquid are used to control the temperature of the primary and secondary separators and ensure the final output The CO2 becomes gaseous to be recycled and reused.
(6) The washer is equipped with an independent internal heating device and a low-temperature cold water circulation system, and the temperature is adjustable within the range of -15℃-200℃.
(1) The pressure and temperature of key monitoring points such as supercritical carbon dioxide fluid cleaning kettle, primary separation device and secondary separation device are designed with pressure sensors and temperature probes, as well as digital secondary instruments with communication ports, which can be networked with computers , Real-time monitoring and recording by the computer.
(2) The carbon dioxide pump and the co-solvent pump have its own flow display function, which can be networked with a computer to collect and control the flow of CO2 and co-solvent in time, and realize real-time computer monitoring.
(4) The back pressure valve is designed after the supercritical carbon dioxide fluid cleaning the kettle, which can accurately control the pressure of the supercritical carbon dioxide fluid cleaning kettle.
(1) Safety valves are designed on the supercritical carbon dioxide fluid cleaning kettle, primary and secondary separators.
(2) The exhaust of carbon dioxide is designed with a manifold, which can be uniformly discharged to the outside for control, which calms the indoor air and reduces the noise of indoor venting.