The double-sided circuit board is a medium layer in the middle, and both sides are wiring layers. Multilayer circuit board is a multi-layer wiring layer. Between each two layers is a dielectric layer, which can be made very thin. The multilayer circuit board has at least three conductive layers, two of which are on the outer surface, and the remaining layer is synthesized in the insulating board. The electrical connection between them is usually realized through the plated through-hole on the cross section of the circuit board. In a series of production processes of PCB boards, there are many matching points. If you are not careful, the boards will have defects, and the quality problems of PCB boards will emerge one after another. Therefore, after the circuit board is made and formed, the detection test becomes an indispensable link. Now let's share with you the faults of PCB and their solutions.

1、 Which layers often occur in the use of multilayer circuit boards

1. Supplier material or process problems;

2. Improper packaging or storage, dampness;

3. Poor design material selection and copper surface distribution;

4. The storage time is too long, exceeding the storage period, and the PCB board is affected with moisture.

Countermeasures: choose the packaging and use constant temperature and humidity equipment for storage. Do a good job of PCB delivery reliability test, for example, the thermal stress test in PCB reliability test. The responsible supplier takes more than 5 times of non delamination as the standard, and will confirm it in the sample stage and every cycle of mass production. Generally, the circuit board manufacturer may only require twice, and only once in several months. The IR test of analog mounting can also prevent the outflow of defective products, which is a necessity for excellent PCB manufacturers. In addition, PCB board Tg should be above 145 ℃, which is safer.

Reliability testing equipment: constant temperature and humidity box, stress screening cold and hot impact test box, PCB reliability testing special equipment.