Vacuum coating (such as magnetron sputtering, evaporation coating, etc.)PECVD）The core requirement isHigh vacuum degree maintenance, low pollution, stable process rhythmThe sealing material, diameter, and opening/closing speed of vacuum valves need to be deeply adapted to the process steps (vacuum pumping, coating, workpiece entry and exit). The following is the specific matching logic:

1、 Sealing material: Suitable for vacuum degree and medium, preventing pollution

The sealing material directly determines the leakage rate, temperature resistance, and pollutant release of the valve, and should be selected based on the vacuum level and medium type of the coating process

1. Match sealing material according to vacuum degree

2. Special requirements for process media

•If corrosive gases (such as chlorine and fluoride) are used in the coating process: priority should be given to selectingPerfluororubber（FFKM） orHastelloy sealTo avoid sealing failure and gas leakage caused by rubber aging;

•If it is an oil-free vacuum system (such as semiconductor coating): It is strictly prohibited to use oil containing sealing materials, and it is necessary to choose “Oil free certification”Rubber or metal seals, paired withMKSUse a dry vacuum pump to avoid oil vapor contamination of the coating layer;

•High temperature coating process (such as high-temperature evaporation coating, temperature>300℃）: SelectionMetal sealing (copper gasket, aluminum gasket) Or high-temperature resistant fluororubber to prevent the sealing material from decomposing and producing pollutants at high temperatures.

3. Compatibility with leak detection system

The leakage rate of the sealing material needs to match the leak detection accuracy of the vacuum system. It is recommended to choose a leakage rate≤10⁻¹⁰ Pa・m³/sThe valve (such asMKSVacuum valve matchingFFKMThe sealing component forms a closed loop with the helium mass spectrometer leak detector to ensure stable vacuum degree in the coating chamber.

2、 Path: Match flow requirements and process rhythm, balance efficiency and vacuum maintenance

The diameter (valve inner diameter) determines the gas extraction speed and workpiece passage capacity, and needs to be calculated comprehensively based on the coating chamber volume, vacuum extraction time, and workpiece size:

1. Core formula for diameter selection (simplified version)

pathD（mm）≈ √(V×S÷t)Among them:

•V: Coating chamber volume（L）；

•SVacuum pump pumping speed（L/s, such asMKS EDGESeries matching vacuum pump);

•tTarget Vacuum Extraction Time（s）.

2. Path matching for different coating scenarios

3. Key precautions

•Excessive diameter can increase the risk of vacuum leakage and requires the use of a higher pumping speed vacuum pump; If the diameter is too small, it will prolong the vacuum pumping time and reduce the production line rhythm;

•Multi channel coating system (such as multi target magnetron sputtering): The main exhaust channel is selected with a large diameter（DN80~DN125）Choose small diameter for branch channels（DN15~DN40）Implement partitioned vacuum control.

3、 Opening and closing speed: adapted to the process to avoid vacuum fluctuations and coating defects

The opening and closing speed (the time for the valve to move from fully closed to fully open) needs to be adjusted according to the core requirements of the process to avoid excessive speed/Slow speed can cause vacuum fluctuations or coating quality issues:

1. Speed matching in different process stages

2. The synergy between speed and sealing material

•Quick opening and quick closing valves: Priority should be given to selecting wear-resistant and impact resistant sealing materials (such as fluororubber and metal seals) to avoid frequent opening and closing that may cause seal wear and extend service life;

•Slow opening and slow closing valves: Silicone rubber seals with better elasticity can be selected to reduce the impact force when the valve is closed and improve sealing reliability.

3. Adapt to the rhythm of the production line

•Batch production line (such as mobile phone glass coating): choose fast opening and closing valves（0.1~0.3 s）, MatchingMKSThe fast start stop function of RF power supply shortens the process time of a single batch;

•High precision customized coating (such as optical lenses): using slow opening and slow closing valves（2~3 s）To avoid defects such as uneven coating thickness and color difference caused by vacuum fluctuations.

4、 Selection of comprehensive matching cases

with “100 LMagnetron sputtering coating chamber (high vacuum)10⁻⁷ PaMass production of mobile phone glass”For example:

1. Sealing material: selectionFFKMPerfluororubber (low gas release rate, plasma corrosion resistance), matched with ultra-high vacuum requirements;

2. Diameter: Coating chamber volume100 LVacuum pump pumping speed50 L/sTarget Vacuum Extraction Time60 sCalculate the diameter≈√(100×50÷60)≈9 mmActual selectionDN40（1.5'）Path, reserve redundancy;

3. Opening and closing speed: used during the vacuum pumping stage0.2 sQuick open solenoid valve, for switching coating media1.5 sSlowly open the pneumatic valve for workpiece entry and exit3 sSlowly open the electric valve to balance efficiency and stability.

Hangzhou Yushi Technology Co., LtdFocusing on providing technical services and solutions related to flow, pressure, vacuum detection and control for industrial and scientific research customers, the company acts as an agent and distributor in the United StatesALICAT、 Swiss Vogtlin, American MKS, Japanese EBARA and other brands, combined with their agent products, provide customers with high-quality flow and pressure monitoring solutions, aiming to improve customers' research and production efficiency, improve their manufacturing processes, and promote their scientific research and innovation progress.