Back pressure leakage detection method is a combination of pressure filling leakage detection and vacuum leakage detection.
In vacuum coating equipment, it is most used in nondestructive leak detection technology of sealing parts such as electronic devices and semiconductor devices after sealing.
The leakage detection process can be basically divided into three steps: filling, purifying and leak detection:
1. The pressure filling process is to store the tested parts in the container filled with high pressure leak gas for a certain time.
If there is a leak hole in the tested parts, the leak gas can enter the inside of the tested parts through the leak hole,
and the partial pressure of the leak gas inside the tested parts will increase gradually with the increase of the soaking time and the increase of the inflatable pressure.
2. The purification process is to use a dry nitrogen flow or a dry air flow outside the filling vessel or to spray the inspected piece inside it.
If the gas source is not available, the inspected parts may also be kept static in order to remove the leakage gas adsorbed on the outer surface of the inspected parts.
In the process of purification, because a part of the gas must be lost through the leakage hole inside the tested piece,
which leads to the partial pressure of the leak gas in the tested piece gradually decreasing, and the longer the purification time, the greater the partial pressure drop of the leak gas.
3. The process of leak detection is to put the purified parts into the vacuum chamber connect the leak detector with the vacuum chamber for leakage detection.
Post time: Apr-20-2020