Vacuum Pressure Gauge for an Rtp Vacuum Furnace

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The invention relates to a vacuum pressure gauge system specifically designed for use in rapid thermal processing (RTP) vacuum furnaces, particularly for producing semiconductor chalcogenide layers (e.g., for CIS thin-film solar cells). Unlike prior methods that measured pressure inside the reaction box and suffered from inaccuracies due to temperature fluctuations and membrane size limitations, this invention introduces a separate pressure measuring unit placed outside the RTP furnace. The process gas from the reaction box is led through a heated pipe (kept at a constant temperature to prevent condensation) to this external unit, where the pressure is measured accurately using pressure sensors such as a Pirani gauge. This setup enables high-accuracy, in-situ process pressure measurement, even at very low pressures, and is independent of membrane dimensions within the reaction box.

Use CasesContent extracted from patent full text and abstract with AI.

• Real-time process pressure monitoring in RTP vacuum furnaces used for manufacturing semiconductor thin films (e.g., CIS solar cells).
• Quality control of chalcogenide and similar semiconductor layer deposition by enabling precise and reproducible process gas pressure measurement.
• Integration into vacuum processing equipment across photovoltaic, semiconductor manufacturing, and advanced materials research labs.
• High-accuracy pressure regulation during rapid thermal treatments, especially where process gases are sensitive to condensation and temperature drift.

BenefitsContent extracted from patent full text and abstract with AI.

• Allows highly accurate and reproducible pressure measurements during high-temperature, rapid thermal processes.
• Can measure very low process pressures, even below 0.1 mbar, where previous methods failed.
• Measurement system is insensitive to temperature fluctuations in the reaction chamber, eliminating major sources of error.
• Pressure measurement is independent of the size or type of membrane in the reaction box, making it flexible for various experimental or production setups.
• Prevents condensation of the process gas within the measuring system, maintaining measurement reliability over time.
• Simplifies scaling down equipment for laboratory or small-scale production without losing measurement accuracy.
• Supports better process control, leading to improved film quality and device performance (e.g., in solar cells) by preventing formation of unwanted phases.

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Inventors & Applicants

Patent Abstract

In order to efficiently produce especially semiconducting chalcogenide layers for use in CIS solar cells, a reaction box is inserted into the reaction chamber of a rapid thermal processing (RTP) vacuum furnace. The quality of the layer to be produced is regulated with the help of the process pressure (PP) which is determined in situ by optically measuring the deflection of a membrane in the reaction box, said membrane being used as a pressure sensor. However, said measurement is erroneous because of the large temperature variations during RTP and can be used only with a membrane having a certain minimum size. According to the invention, a separate pressure measuring unit (08) is provided outside the RTP vacuum furnace (05). Said pressure measuring unit (08) can be gas-tightly connected to the reaction box (02) via a supply pipe (11) and comprises a measuring chamber (09) and a pressure sensor (10), preferably a Pirani-type thermal conductivity gauge (15). At least the supply pipe (11) is kept, by means of a heating device (12), at a constant temperature (TA) that is thermally disconnected from the RTP, lies below the process temperature (TP) but above the condensation temperature (TK) of the process gas, and is transferred to the process gas as the measured temperature (TM) when the process gas penetrates into the pressure measuring unit (08).