With the continuous development of high technology, electronic components are being used more and more widely in high-tech industries such as aviation, aerospace, instrumentation, precision measurement and military, which also puts forward higher requirements for the quality of electronic components.
The quality of electronic components directly affects the performance of machinery and equipment, and the electronic products they form must be able to resist the corrosive effects of environmental factors. Therefore, many require excellent sealing performance to prevent external liquid (gas and/or liquid) media from seeping into the interior through structural gaps, openings, or pores, which could adversely affect the performance of electronic components.
Poor sealing performance will not withstand the corrosive effects of environmental factors. In environments with high temperatures, fluctuating humidity, and harmful substances, photosynthesis can occur, causing electrolytic corrosion and damage to the internal wires or plating layers of electronic components. This leads to changes in electrical parameters, reduced performance, or immediate loss of function. Poor sealing results in excessive internal moisture, which can cause solder joint defects at the contact points of relays at extremely low temperatures, thus rendering them ineffective. Furthermore, when electronic components require sealing for purposes such as protection against electromagnetic radiation or light sources, poor sealing can directly cause malfunction. These adverse conditions will seriously affect the stability of electronic component applications. Therefore, almost all electronic component manufacturers must conduct leak testing on electronic components to check their sealing performance and select components with excellent sealing performance.
The selection of electronic components is determined by leak testing, identifying those with sealing problems caused by the use of substandard sealing materials or poor manufacturing processes. Leak testing is divided into two processes: fine leak testing and coarse leak testing. Fine leak testing uses a hydrogen mass spectrometer with a backpressure method, while coarse leak testing currently commonly uses the fluorinated oil bubble method. Leak testing experiments generally begin with fine leak testing, followed by coarse leak testing.
Fluorinated oil possesses excellent polarization properties, excellent chemical plasticity, high dielectric strength, and excellent resistance to high and low temperature tests. It is corrosion-resistant to electronic components and does not affect the various parameters of the components, making it an ideal liquid for coarse leak detection experiments. The key to coarse leak detection mainly includes two steps: injecting low-boiling-point fluorinated oil and heating high-boiling-point fluorinated oil to detect leaks by bubbles.
The first step is to place the cleaned electronic component under test into a pressurizing vessel, seal the vessel, and then vacuum-pack it. A low-boiling-point fluorinated oil is then added to the vessel under vacuum, completely submerging the component. The vessel is then pressurized with nitrogen (N2) for a certain period. If the component has a standard orifice plate, the low-boiling-point fluorinated oil will be forced into the inner wall of the component. After pressurization, the electronic component is removed and left to air dry for a certain period to remove the low-boiling-point fluorinated oil from its surface.
The second step is to immerse the dried device under test in high-boiling-point fluorinated oil heated to 125°C, ensuring the top of the device is submerged at least 5 cm deep. After immersion for a certain period, observe the electronic components under test using a high-magnification microscope to check for air bubbles. If bubbles are continuously released, it indicates a problem with the sealing performance of the electronic components under test.
In summary, with the continuous development of high technology, its application will become more widespread, and the quality requirements for electronic components will become increasingly stringent. As an essential process for testing the quality of electronic components, the requirements for the leak detection fluid are also becoming increasingly stringent.
