Brooks Instrument released Aug. 25 its GP200 Series fully pressure-insensitive, pressure-based, mass flow controller (P-MFC) designed for etch and chemical vapor deposition (CVD) processes in semiconductor manufacturing. GP200 operates well in high-vacuum conditions and above atmospheric pressure conditions intrinsic to etch and CVD processes.
MFCs are the most important component in the gas delivery systems used to produce silicon wafers. They must precisely deliver inert, corrosive and reactive gases to the process chamber, even when operating at very low vapor pressures. However, conventional, discrete P-MFCs can operate under high-vacuum conditions, but degrade in performance and control range as outlet pressures increase. By offering a greater operating range than conventional P-MFCs, GP200 Series can improve etch process performance and expand the application scope to include CVD processes.
“Historically, thermal MFCs were more heavily used in semiconductor manufacturing gas delivery systems. However, pressure-based MFCs are growing in popularity because they provide significant advantages,” says Dr. Mohamed Saleem, CTO at Brooks Instrument. “We designed our pressure-insensitive GP200 Series to optimize etch and CVD processes with highly precise, repeatable gas delivery.”
GP200 Series unit features a patented architecture that overcomes the limitations of conventional P-MFCs to provide the most precise process gas delivery, even when delivering low-vapor-pressure process gases. It includes several unique design aspects, including:
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Integrated differential pressure sensor paired with an absolute pressure sensor to compute pressure drop, instead of using two discrete pressure sensors, typically found in conventional P-MFCs. This combination reduces measurement uncertainty from calibration issues and improves the accuracy, repeatability and drift performance in semiconductor processes.
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Laminar flow element designed for low pressure drop with a differential pressure sensor that's optimally ranged. This design makes it possible to accurately measure the flow of challenging low vapor pressure process gases used in etch processes, including silicon tetrachloride, boron trichloride and hexafluorobutadiene. Where conventional P-MFCs require high inlet pressures to operate, the high accuracy and repeatability of GP200 in all operating conditions make it suitable for both standard pressure and critical low vapor pressure gases.
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Downstream valve architecture. By positioning the control valve downstream of the flow restrictor, GP200 is essentially immune to downstream pressure fluctuations, as well as upstream pressure fluctuations. This enables flow delivery into pressures as high as 1200 Torr.
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Ultra-fast, highly repeatable transient response: This downstream valve architecture also enables rapid shutdown and switching of recipe set points for pulsed gas delivery. Fast response times enable tighter process control, providing precise, highly repeatable gas flow delivery with matched transient response.
