The ceramic package chip uses a helium mass spectrometry leak detector for leak detection

Laser chip is an important part of optical communication equipment, which has high return loss and low insertion loss. High reliability, stability, mechanical wear resistance and corrosion resistance, easy to operate and so on. The laser chip is packaged in the Box, the requirements for sealing are extremely high, the chip package, once there is a leak, the chip will fail!

After the installation of the laser chip, the leakage rate is required to be less than 5×10-8mbar.l/s, if the seal is not enough will affect its performance and accuracy, so the need for leakage detection. Due to the small size of the packaged laser chip device and the inability to vacuum or fill helium directly, Nuella recommends the helium mass spectrometry leak detector “back pressure method” for leak detection.

Helium leak detection method: First, the packaged components are put into a container filled with helium, and pressurized, so that hydrogen enters the tube shell through a small hole; Then take it out and blow the remaining helium on the surface of the tube shell with compressed air; A mass spectrometer is then used to detect the helium leaking from the shell.

Helium leak detection is the use of helium to check for small holes in the packaging of electronic components. Because of the small size of helium atoms, it is easy to pass through small holes and enter the inside of the shell, so this detection method can detect small holes in small size (that is, it can detect small holes with a leakage rate of about 1011~10-12cm2/sec), and the sensitivity is comparable to the radioactive leak detection method, but it is simpler than the radioactive leak detection method.

Encapsulation laser chip leak detection method

After the laser chip is packaged inside the Box, a leak test is required for its own tightness. Due to the small size of the packaged laser chip device, and can not be vacuumed or directly filled with helium, Shanghai Bodong recommends the use of helium mass spectrometry leak detector “back pressure method” leak detection, the specific practice is as follows:

1. Put the laser chip under test into the vacuum holding tank. The pressure and time are set according to the leakage rate

2. Remove the encapsulated laser chip and use air or nitrogen to purge the surface helium

3. Put the packaged laser chip into the vacuum test tank, and connect the test tank to the helium mass spectrum leak detector air inlet

4. Start the helium mass spectrometer leak detector, and set the leakage rate to 5×10-8mbar.l/s in vacuum mode for leak detection.