The design and performance analysis of the vacuum system for a sputtering coating monomer machine are crucial for ensuring the quality and efficiency of thin film deposition. Below is a summary of the relevant content:
I. Design of the Vacuum System for a Sputtering Coating Monomer Machine
Design Requirements
Ultimate Vacuum Level: The base vacuum level required for the magnetron sputtering coating process is 5×10⁻³ Pa. The ultimate vacuum level of the vacuum chamber under no-load conditions should be at least one order of magnitude higher than the base vacuum level (5×10⁻⁴ Pa).
Pumping Time: The time it takes for the vacuum system to reach the base vacuum level from startup should be less than 60 minutes.
Leak Rate: The leak rate of the vacuum system should be less than or equal to 1×10⁻⁷ Pa·L/s.
Process Adjustment: The vacuum system should be able to adjust the process gas pressure according to different requirements.
Vacuum System Configuration
Vacuum Pump Selection: A combination of a roughing pump (such as a rotary vane mechanical pump) and a high-vacuum pump (such as a turbomolecular pump) is used as the vacuum pumping system. The turbomolecular pump has a low ultimate pressure (5×10⁻⁷ Pa), making it suitable for high-vacuum environments.
System Layout: A high-vacuum electric gate valve is installed between the vacuum chamber and the turbomolecular pump. The fore pump is connected to the pneumatic valve via a low-vacuum pipeline to evacuate the vacuum chamber. The vacuum chamber is equipped with various sensors, such as Pirani gauges, ionization gauge tubes, and capacitive pressure sensors, to monitor the status inside the chamber.
Ultimate Vacuum Verification
The ultimate vacuum level of the designed vacuum system was verified using the MOLFLOW+ software. The internal pressure of the vacuum chamber was found to be better than 2.7×10⁻⁴ Pa.
In actual testing, a helium mass spectrometer leak detector was used for leak detection, and the leak rate was found to be 10⁻¹⁰ Pa·m³/s, which meets the design requirements.
II. Performance Analysis of the Vacuum System for a Sputtering Coating Monomer Machine
Pumping Performance
A pumping calculation model for the vacuum system was established. By solving the model, a pumping curve was obtained and compared with the actual test results. The results showed that the pumping curve obtained from the calculation model deviates from the test values by less than 5%, which can be used for the performance analysis of high-vacuum systems.
During the pumping process, the pumping speed changes in multiple stages as the gas flow state changes, and the influence of leakage and outgassing on the pumping speed is constantly changing, causing fluctuations in the pumping curve.
Practical Application Effects
The design and performance analysis of the vacuum system for a sputtering coating monomer machine ensure that the system can meet the requirements for thin film deposition in a high-vacuum environment, thereby ensuring the stability of the process and the quality of the thin film.
