What should be noted when customizing PECVD electric furnaces?

When customizing a PECVD (plasma enhanced chemical vapor deposition) electric furnace, it is necessary to comprehensively consider multiple dimensions such as process requirements, equipment performance, safety and environmental protection, operational convenience, and cost-effectiveness. The following are key precautions and specific instructions:

1. Clarify process requirements and objectives
Film type and performance requirements
Material selection: Determine the reaction gas combination based on the target film (such as Si ∝ N ₄, SiO ₂, a-Si, DLC, etc.). For example, depositing silicon nitride requires SiH ₄+NH3, while depositing silicon oxide requires SiH ₄+N ₂ O.
Electrical properties: If doping is required (such as n-type or p-type semiconductors), doping gases such as PH ∝ and B ₂ H ₆ should be added, and the doping concentration should be precisely controlled.
Optical performance: For anti reflection layers or optical coatings, it is necessary to optimize parameters such as film refractive index and transmittance.
Process parameter range
Temperature control: Determine the deposition temperature range (such as room temperature to 500 ℃), and require the equipment to have high-precision temperature control (within ± 1 ℃) to avoid temperature fluctuations affecting the crystallinity of the film.
Pressure range: Select the vacuum degree range (such as 1Pa to atmospheric pressure) according to the process requirements, and ensure pressure stability (within ± 5%).
RF power: Specify the RF power required for plasma excitation (such as 13.56MHz), and support adjustable power to accommodate different material deposition.

2. Equipment performance and compatibility
Heating system design
Heating method: Choose resistance heating, induction heating, or infrared heating, and determine according to the furnace size and temperature uniformity requirements. For example, large-sized furnaces require zone heating to reduce temperature differences.
Heating element material: Select high temperature resistant and corrosion-resistant materials (such as graphite and molybdenum) to extend the service life of the equipment.
Gas supply system
Gas purity: The purity of the reaction gas should be ≥ 99.995%, and the purity of the carrier gas (such as H ₂, Ar) should be ≥ 99.999% to prevent impurities from contaminating the film.
Gas path design: Independent gas path controls reaction gas, carrier gas, and doping gas to avoid cross contamination; Configure a quick switching valve to support multi gas process switching.
Mass Flow Controller (MFC): High precision MFC (± 1% FS) is selected to ensure stable gas flow and directly affect the uniformity of the film.
Vacuum system configuration
Vacuum pump type: Choose a dry pump or oil sealed pump according to the maximum vacuum requirement (such as 4 × 10 ⁻ ³ Pa), and consider pumping speed and maintenance costs.
Vacuum gauge accuracy: High precision vacuum gauges (such as capacitor film gauges) are used to monitor the pressure inside the furnace in real time, ensuring process repeatability.
Plasma excitation source
RF power supply: Choose a stable and reliable RF power supply (such as 13.56MHz), and support adjustable power (such as 100W to 5kW) to adapt to different material deposition.
Electrode design: Optimize electrode structures (such as parallel plates, cylindrical shapes) to enhance plasma uniformity and reduce film defects.

3. Safety and Environmental Design
Gas safety protection
Toxic gas treatment: For toxic gases such as PH ∝ and B ₂ H ₆, leak detection and automatic cut-off devices are installed, and exhaust gas combustion towers or wet scrubbing towers are set up for treatment.
Flammable gas protection: Flammable gases such as H ₂ and SiH ₄ require explosion-proof design, such as inert gas protection and explosion-proof electrical appliances.
Mechanical safety design
Furnace door interlock: Heating is prohibited when the furnace door is not closed to prevent personnel from misoperation.
Overtemperature protection: Set up multi-level overtemperature alarm and automatic power-off function to avoid equipment damage.
Environmental compliance
Exhaust gas emissions: comply with local environmental standards (such as VOCs emission limits) and be equipped with efficient exhaust gas treatment devices.
Noise control: Low noise vacuum pumps and fans are used to reduce the impact on operators.

4. Convenient operation and maintainability
Human Computer Interaction Interface
Touch screen control: supports process parameter settings, real-time monitoring and data recording, simplifying the operation process.
Process database: Pre stored common process parameters (such as gas flow rate, temperature, time), supporting quick calling and modification.
modular design
Removable components: The furnace, electrodes, gas pipelines, etc. adopt modular design for easy maintenance and replacement.
Quick changeover: Supports quick replacement of substrates or fixtures of different sizes, improving production flexibility.
Remote monitoring and diagnosis
IoT interface: supports remote monitoring of device status, fault warning, and data analysis, reducing downtime.
Self diagnostic function: The device has fault self checking and alarm functions, making it easy to quickly locate problems.

5. Cost benefit balance
Initial investment and operating costs
Equipment grade: Choose economical, standard, or high-end equipment based on budget, balancing performance and cost.
Gas consumption: Optimize the gas flow ratio, reduce waste (such as SiH ₄: NH ∝=1:3~5), and lower operating costs.
Energy consumption control: adopting efficient heating elements and energy-saving design to reduce power consumption.
Long term maintenance costs
Wear life of vulnerable parts: Choose components with high durability (such as heating elements, vacuum pumps) to reduce replacement frequency.
After sales service: Require suppliers to provide comprehensive technical support and spare parts supply to shorten maintenance cycles.
Production efficiency and yield
Sedimentation rate: Choose equipment with efficient sedimentation rate to shorten the production cycle.
Film uniformity: Ensure uniform film thickness and composition to improve product yield.

6. Customized Additional Features
In situ detection technology
Integrated spectroscopic ellipsometer, quartz crystal microbalance (QCM) and other in-situ detection devices, real-time monitoring of film thickness and composition, and optimization of process parameters.
Multi process compatibility
Support the combination of PVD, ALD and other deposition techniques to form complex multilayer structures or achieve specific functions.
Automated Integration
Integrate with upstream and downstream equipment such as cleaning machines and testers to achieve fully automated production lines and improve production efficiency.