Can the rapid temperature rise and fall annealing furnace be evacuated?

The rapid temperature rise and fall annealing furnace (RTP) can evacuate, but it needs to be designed and configured according to the equipment type and process requirements. The following is a detailed analysis:

1. Feasibility of vacuum function
Basic design support
Vacuum chamber structure: Some RTP equipment adopts a sealed furnace chamber design, equipped with vacuum pump interfaces (such as mechanical pumps, molecular pumps), which can achieve low vacuum environment (usually ≤ 10 ⁻ ³ Pa).
Typical application scenarios:
Avoid material oxidation (such as metal film annealing, semiconductor device manufacturing).
Reduce the interference of gas molecules on heat transfer (such as high-precision temperature control).
Cooperate with specific processes (such as vacuum coating, ion implantation cleaning).
Limitations of Non Vacuum Equipment
RTP with open or ordinary sealed design may not be able to be evacuated and require the introduction of inert gases (such as N ₂, Ar) to achieve a protective atmosphere, but cannot reach a vacuum state.

2. Core configuration of vacuum RTP
Vacuum system components
Vacuum pump: Choose according to the vacuum degree requirement:
Mechanical pumps (rotary vane pumps, slide valve pumps): coarse vacuum (10 ⁻¹~10 ⁻³ Pa), low cost.
Molecular pump: High vacuum (10 ⁻³~10 ⁻⁴ Pa), requiring the support of a front-end mechanical pump.
Vacuum valve and pipeline: Made of stainless steel material, equipped with pneumatic or electric valves to achieve rapid pumping and sealing.
Vacuum gauge: resistance gauge (low vacuum) or ionization gauge (high vacuum), real-time monitoring of furnace chamber pressure.
Heating system adaptation
Heating method:
Infrared lamp heating: It is necessary to avoid temperature fluctuations caused by changes in thermal radiation efficiency of the lamp under vacuum.
Resistance wire heating: It is necessary to ensure that the heating element does not evaporate under vacuum (such as using high melting point materials such as tungsten and molybdenum).
Temperature control: Heat conduction decreases in a vacuum environment, and PID parameters need to be adjusted or an auxiliary heating zone needs to be added to compensate for temperature uniformity.
Sample stage and transmission
Vacuum compatible design: The sample stage needs to use oil-free lubrication or magnetic fluid sealing technology to avoid contaminating the vacuum environment.
Fast loading: Some equipment is equipped with vacuum manipulators to achieve rapid loading/unloading of samples in the vacuum chamber (such as photovoltaic cell testing).

3. Application of Vacuum RTP in Photovoltaic Industry
Crystal silicon solar cell
Ion implantation repair: Annealing under vacuum can avoid the reaction between doping elements (such as boron and phosphorus) and oxygen, improving activation efficiency.
Surface passivation treatment: Vacuum environment reduces the unevenness of oxide layer thickness and increases the short-circuit current (Jsc) of the battery.
Case: A certain photovoltaic enterprise adopts vacuum RTP processing for N-type TOPCon cells, which reduces the composite current density of the passivation layer and improves efficiency.
Thin film solar cells
CIGS selenization process: Vacuum annealing can precisely control the partial pressure of selenium vapor, forming a uniform CIGS absorption layer and improving battery efficiency.
Crystallization of perovskite thin films: Vacuum environment reduces solvent volatilization residue, promotes densification of perovskite grains, and enhances film stability.
Research and development of photovoltaic materials
Synthesis of Nanostructured Materials: Vacuum annealing can control the size distribution of nanoparticles and adjust their light absorption properties (such as quantum dot solar cells).
Transparent conductive oxide (TCO): Vacuum annealing improves the crystallinity of ITO thin films, reduces resistivity, and increases transmittance.

4. Technical advantages of vacuum RTP
Improvement of process purity
Eliminating impurities such as oxygen and water vapor from contaminating materials, suitable for high-purity semiconductor or photovoltaic material processing.
Reduce gas convection heat dissipation and improve temperature control accuracy (such as within ± 1 ℃).
Special process implementation
Support processes such as low-pressure chemical vapor deposition (LPCVD) to deposit thin films (such as SiNx passivation layers) under vacuum.
Cooperate with plasma source to achieve vacuum plasma annealing and enhance the surface modification effect of materials.
Production efficiency optimization
Rapid vacuuming (such as from atmospheric pressure to 10 ⁻ Pa in just 5 minutes) shortens the process cycle.
The vacuum environment reduces the adsorption of gas on the sample surface and accelerates the temperature drop rate during the cooling stage.

5. Selection and usage precautions
Vacuum degree requirement matching
Select vacuum level according to process requirements:
Low vacuum (10 ⁻¹~10 ⁻³ Pa): suitable for ordinary oxidation protection.
High vacuum (10 ⁻³~10 ⁻⁴ Pa): suitable for high-purity material processing or special physical processes.
Device compatibility verification
Confirm that the device supports vacuum technology:
Check whether the furnace chamber material (such as stainless steel 316L) is resistant to vacuum corrosion.
Verify the stability of heating elements, sensors, and other components under vacuum.
Safety operation standards
Before vacuuming, ensure that there are no volatile substances (such as residual organic solvents) in the furnace chamber.
Slowly introduce inert gas when breaking the vacuum to avoid damage to the sample due to sudden pressure changes.
Regularly check the sealing of the vacuum system (such as using a helium mass spectrometer leak detector to detect a leakage rate of<1 × 10 ⁻⁹ Pa · m ³/s).

Conclusion: The rapid temperature rise and fall annealing furnace can achieve vacuum pumping function by configuring a vacuum system, especially in scenarios such as high-purity material processing and special film preparation in the photovoltaic industry, which has irreplaceable advantages. When selecting, it is necessary to clarify the parameters such as vacuum degree and heating method according to the process requirements, and strictly follow the safety operation specifications.