There is such a teaching method in PVD vacuum coating equipment called back pressure leak detection method
There is such a teaching method in the PVD vacuum coating equipment called the back pressure leak detection method. Do you know this method? The following editor will give you a brief introduction.
The back pressure leak detection method is a combination of pressure leak detection and vacuum leak detection. It is used in the non-destructive leak detection technology of sealed electronic devices, semiconductor devices, etc. after sealing. This method can be divided into the following three steps: pressurization, purification, and leak detection.
1. The charging process is to store the tested part in a container filled with high-pressure leaking gas for a certain period of time. If the tested part has a leak, the leaking gas can enter the inside of the tested part through the standard leak. , And as the immersion time increases and the pressure of the inflation system increases, the partial pressure of the leaking gas inside the test piece will inevitably be affected and gradually increase.
2. In the purification process, dry nitrogen flow or dry air flow is used to spray the inspected parts outside or inside the pressurized container.
If there is no gas source, the tested part can be placed to remove the exposed gas adsorbed on the surface of the tested part. During the purification process, part of the gas will leak from the inside of the sample, resulting in a gradual decrease in the partial pressure of the gas leakage, and the longer the purification time, the greater the partial pressure drop of the gas leakage.
3. The leak detection process is to put the cleaned test piece into the vacuum chamber, connect the leak detector to the vacuum chamber, and perform leak detection.
After vacuuming, due to the pressure difference, the leaking gas can flow out from the inside of the tested part through the leak, and then enter the leak detector according to the vacuum chamber, and judge the existence of the leak according to the output signal of the leak detector. The size of the problem and its leak rate.
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