Precautions for using a rapid temperature rise and fall annealing furnace

The rapid temperature rise and fall annealing furnace (RTP) is widely used in fields such as semiconductors, photovoltaics, and new materials due to its rapid temperature rise and fall characteristics. However, improper operation can easily cause equipment failure or process defects. The following are key precautions during use, covering preparation before operation, monitoring during operation, safety protection, and maintenance:

1. Preparation before operation
Equipment inspection
Mechanical structure: Check whether the furnace lifting system and furnace door sealing strip are intact, ensuring no looseness, wear or deformation; Manually test whether the furnace door switch is flexible to avoid vacuum leakage or contamination of the furnace atmosphere.
Electrical system: Confirm that the power supply line is not damaged and the grounding is good; Check whether the contacts of control components such as relays and contactors are clean, free from oxidation or adhesion; Verify the compatibility between PLC program and process parameters.
Heating element: Check whether the halogen lamp, graphite heater and other elements are intact, without the risk of breakage or short circuit; Measure the resistance value of the heating element, and compare it with the nominal value with a deviation of no more than ± 5%.
Sensors and instruments: calibrate temperature sensors (such as S-type thermocouples) and pressure sensors (if applicable) to ensure measurement accuracy; Check if the temperature controller, flow meter and other instruments display normally.
Process parameter setting
Temperature curve: Set reasonable heating rate, holding time, and cooling rate based on material characteristics (such as silicon, gallium nitride, perovskite) to avoid material cracking or performance degradation caused by thermal stress.
Atmosphere control: If inert gas protection (such as N ₂ Ar）， Set the gas flow rate (e.g. 5-20L/min) and pressure (e.g. 0.1-0.5MPa) to ensure that the oxygen content in the furnace is below the process requirements (e.g.<10ppm). Vacuum degree (if applicable): Set the vacuum pump start-up threshold (e.g. -90kPa) and holding time to avoid vacuum leakage affecting the annealing effect. Sample preparation Size and placement: The sample size should be smaller than the effective space of the furnace (such as diameter ≤ 200mm) to avoid obstructing the heating element; Uniformly distribute samples to reduce temperature gradients (such as temperature uniformity ≤ ± 2 ℃). Surface cleaning: Remove impurities such as oil stains and oxides from the sample surface to prevent contamination or defects during annealing. Fixture selection: Use high-temperature resistant, non-magnetic fixtures (such as quartz, ceramics) to avoid the release of impurities or deformation of metal fixtures at high temperatures.

2. Monitoring during operation

Temperature monitoring

Real time curve: Monitor the actual temperature curve through a temperature controller or upper computer software to ensure it matches the set curve; If the temperature fluctuation exceeds ± 1 ℃, immediately check the heating element, sensor or control circuit. Overtemperature protection: Enable the overtemperature alarm function (such as setting the alarm threshold to 1250 ℃), and automatically cut off the heating power when the temperature exceeds the safe value to prevent equipment damage. Atmosphere and vacuum monitoring Gas flow rate: Regularly check the reading of the gas flow meter to avoid oxidation caused by insufficient flow rate or waste caused by excessive flow rate; If using a mass flow meter (MFC), it is necessary to calibrate the gas type in advance. Vacuum degree: Monitor the pressure inside the furnace through a vacuum gauge. If the rate of vacuum degree decrease is abnormal (such as>1kPa/min), check the sealing of the vacuum pump, valve or furnace body.
Equipment status monitoring
Abnormal noise: If you hear the sound of heating element bursting or motor abnormal noise during operation, immediately stop the machine for inspection to prevent the fault from expanding.
Odor or smoke: If you smell the burnt insulation material or see smoke coming from the furnace, immediately cut off the power and ventilate, and check whether the heating element or electrical circuit is short circuited.

3. Security protection
personal protection
High temperature protection: Wear insulated gloves and protective face shields during operation to avoid direct contact with the furnace body or sample (high temperature can reach 1200 ℃).
Electrical safety: Wear insulated shoes and avoid operating in humid environments; During maintenance, disconnect the power supply and hang a “Do Not Close” sign.
Gas safety: If toxic gases (such as H ₂) are used, they must be operated in a fume hood and equipped with a gas leak alarm; Prevent suffocation risk during inert gas operation.
Equipment safety
Emergency stop function: Familiarize yourself with the location of the emergency stop button. In case of an emergency (such as temperature loss or vacuum leakage), immediately press the emergency stop button to cut off heating and gas supply.
Overload protection: Ensure that the total current of the equipment does not exceed the rated value to avoid overheating or fire in the circuit caused by overload operation.
Grounding protection: Regularly check the grounding resistance of equipment to prevent electric shock accidents caused by leakage.

4. Maintenance and upkeep
routine maintenance
Cleaning the furnace: After each annealing, use a vacuum cleaner or soft bristled brush to clean the residue inside the furnace to avoid impurities affecting the next annealing effect; If the furnace is severely polluted, it can be wiped with anhydrous ethanol.
Check the sealing strip: Regularly inspect the furnace door sealing strip for aging or damage, and replace it in a timely manner to maintain the vacuum degree or atmosphere purity.
Lubrication lifting system: Apply high-temperature lubricating grease (such as molybdenum disulfide) to mechanical components such as gears and chains to reduce wear and extend service life.
regular maintenance
Replace heating elements: Regularly replace heating elements based on the lifespan of halogen lamps (such as 3000 hours) or the degree of oxidation of graphite heaters to ensure heating rate and temperature uniformity.
Calibrate sensors: Calibrate temperature and pressure sensors every 3-6 months to correct measurement errors; If using an infrared thermometer, it is necessary to regularly clean the lens and calibrate it.
Check electrical circuits: Check power lines and control cables for aging or damage every six months, and replace wires with damaged insulation layers; Tighten the wiring terminals to prevent poor contact from causing malfunctions.
Long term shutdown maintenance
Moisture proof treatment: If the equipment is not used for a long time, a desiccant (such as silicone) should be placed in the furnace and the furnace door should be sealed to prevent humid air from entering and causing electrical components to short circuit.
Regular power on: Power on and run once every 1-2 months (such as heating up to 200 ℃ and holding for 1 hour) to dispel moisture in the furnace and check if the equipment is functioning properly.