Customized PECVD electric furnace thermal sensitive substrate coating

Customized PECVD electric furnace achieves high-quality thin film deposition in thermal sensitive substrate coating through low-temperature plasma technology. The key lies in precise control of temperature, plasma parameters, and process flow to meet the requirements of flexible electronics, plastic substrates, and other materials. The following analysis is conducted from five dimensions: technical principles, core advantages, application scenarios, process flow, and selection suggestions:

1. Technical principle: Chemical deposition driven by low-temperature plasma
PECVD (Plasma Enhanced Chemical Vapor Deposition) uses radio frequency power to excite gas ionization, forming a plasma mixture of high-energy electrons, ions, and active groups. These active species can react with the substrate surface at low temperatures (room temperature to 350 ℃) to form solid thin films. For example:
Silicon nitride deposition: SiH ₄+NH ∝ → Si ∝ N ₄+H ₂ ↑, plasma activation reaction, reducing deposition temperature.
Silicon oxide deposition: SiH ₄+O ₂ → SiO ₂+2H ₂ ↑, low-temperature film formation is achieved by plasma decomposition of gas molecules.

2. Core advantage: Balance between low-temperature process and thin film performance
Low temperature compatibility
The substrate temperature can be controlled between 200-450 ℃ to avoid damage to flexible substrates (such as polyimide) or plastics caused by high temperatures. It is suitable for wearable devices, flexible displays, and other fields.
For example, when depositing silicon nitride films on plastic substrates, the process temperature can be controlled below 250 ℃.
High sedimentation rate
The deposition rate is faster than traditional CVD and suitable for large-scale production.
Controllable film quality
By adjusting the RF power, gas flow rate, and pressure, the composition, refractive index, and stress of the thin film can be precisely controlled.
For example, adjusting the nitrogen flow rate can optimize the film density, and increasing the temperature by 100 ℃ can increase the density.
Uniformity and adhesion
Better uniformity of film thickness to meet advanced process requirements; Plasma bombardment of substrate surface enhances film adhesion.

3. Application scenario: Diversified demand for thermal sensitive substrates
flexible electronics
Substrate: Polyimide (PI), Polyethylene terephthalate (PET).
Application: Deposition of transparent conductive oxide (ITO) thin films for flexible display screens; Deposition of silicon nitride/silicon oxide stack as a water oxygen barrier layer to extend device lifespan.
Plastic based packaging
Substrate: polycarbonate (PC), acrylonitrile butadiene styrene copolymer (ABS).
Application: Deposition of aluminum oxide (Al ₂ O3) thin film as a back passivation layer to reduce composite losses and improve solar cell conversion efficiency.
Biomedical devices
Substrate: Medical grade polymer (such as polylactic acid PLA).
Application: Deposition of diamond-like carbon (DLC) or SiC thin films to reduce inflammation in implantable devices; Deposition of piezoelectric materials (such as ZnO) for wearable health monitoring.

4. Process flow: precise control from pre-processing to post-processing
Substrate cleaning and pretreatment
Use chemical solvents such as acetone and isopropanol to remove surface oil stains, and activate the surface by cleaning with O ₂ plasma.
Establishment of vacuum environment
Reduce the chamber pressure to below 10 ⁻ Pa through mechanical and molecular pumps to avoid impurity contamination.
Gas Introduction and Plasma Excitation
Introduce precursor gases (such as SiH ₄, NH3) and carrier gases (such as Ar), and excite the plasma with a radio frequency power source.
thin film deposition
Control the substrate temperature (200-450 ℃), RF power, and gas flow rate to deposit the target thin film. For example, during polycrystalline silicon coating, the furnace tube temperature is often set at 450 ℃.
post-processing
Annealing treatment (600-850 ℃): eliminates internal stress in the film and improves electrical performance.
Cleaning: Remove surface residues to ensure the purity of the film.

5. Selection suggestion: Key parameters for customizing PECVD electric furnace
Temperature control accuracy
Select equipment equipped with PID control and self-tuning adjustment technology to achieve a temperature control accuracy of ± 1 ℃ and ensure the stability of film quality.
Plasma source type
Direct plasma source: suitable for large-area substrates with high deposition rate.
Indirect plasma source (such as microwave plasma): reduces the damage of plasma to the substrate and is suitable for precision devices.
Gas delivery system
Selecting a Mass Flow Meter (MFC) for precise control of gas flow rate, supporting multi gas mixing, and meeting the requirements of complex thin film deposition.
Cavity design
Horizontal/vertical tubular structure: suitable for long strip substrates (such as flexible display substrates).
Rotation tilt function: improves film uniformity, suitable for complex shaped substrates.
Security and Automation
Equipped with LCD touch control system, supporting multi segment programmable temperature curve settings; Integrated safety interlock device to prevent gas leakage or equipment overload.