Mitmekihiline PCB compared to single panel PCB, regardless of its internal quality, through the surface, we can see the differences, these differences are critical to the durability and functionality of the PCB throughout its life. The main advantage of PCB multilayer: this board is oxidation resistant. Diversified structure, high density, surface coating technology, to ensure the quality of the circuit board is safe, can be at ease with the use. The following are the important characteristics of high reliability multilayer boards, that is, the advantages and disadvantages of PCB multilayer boards:

1. The copper thickness of the hole wall of PCB multilayer board is normally 25 microns;

Advantages: Enhanced reliability, including improved Z-axis extension resistance.

Disadvantages: But there are certain risks: problems with the possibility of failure under load conditions, in actual use, during blowing or degassing, electrical connectivity during assembly (inner layer separation, hole wall rupture) or under load conditions. IPC Class2 (standard for most factories) requires PCB multilayer boards to be less than 20% copper plated.

2. No welding repair or open circuit repair

Benefits: Perfect circuitry ensures reliability and safety, no maintenance, no risk.

Cons: PCB multilayer is open if serviced improperly. Even if properly fixed, there may be a risk of failure under load conditions (vibration, etc.), which may lead to failure in actual use.

3. Exceeds the cleanliness requirements of IPC specifications

Advantages: Improve the cleanliness of PCB multilayer board can improve reliability.

Risks: Residue on the wiring panel, accumulation of solder can pose a risk to the solder shield, ionic residue can lead to the risk of corrosion and contamination of the weld surface, which can lead to reliability issues (poor welds/electrical failures) and ultimately increase the probability of actual failures.

4. Strictly control the service life of each surface treatment

Advantages: welding, reliability and reduced risk of moisture intrusion

Risks: Surface treatment of old PCB multilayer boards may lead to metallographic changes, there may be solder problems, while water intrusion may lead to problems during assembly and/or actual use of layering, separation of inner wall and wall (open circuit), etc.

Whether in the manufacturing and assembly process or in actual use, PCB multilayer board must have reliable performance, of course, this is related to the equipment and technology level of PCB board factory.