PCBs employed by base station-relevant communication equipment and cloud servers have to be of high frequency material featuring a low dielectric constant and dissipation factor to meet the requirements of high frequency and high speed mandated by 4G/5G and the IoT. There is one problem. The resin and fiber glass contained in specially designed dielectric materials suffer weak bonding strength which may lead to risks of pad cratering.
The Superiority of iST
Plant solder ball at top pad
Pull up solder ball with CBP test
Determine failure mode with 3D OM. This photo shows fiber exposure due to pad cratering.
Run board bending test first
Detect location and grade of minor break sound source with sensor of AE software
Capture cross section at position of crack with 3D OM
- Cold Ball Pull Test(CBP Test):
The CBP test determines the strength of high frequency and high speed and ordinary materials, as well as assessing the performance of individual materials under different process settings (IPC-9708) by detecting cracks in PCB materials in PCBs due to mechanical stress or broken surface beneath the pad with mounted components.
- Acoustic Emission Test(AE Test):
The AE test can be used on mounted PCBs without powering them up. Combing board bending and AE tests, AE test identifies the sources of sounds when boards suffer minor breaks subject to stress. It acutely identifies the strength of high frequency and ordinary material of PCBs. (IPC-9709)