Quality assurance of PCB multilayer boards

The quality of PCB multilayer boards is defined in IPC, the surface technology is anti-oxidation, the vacuum packaging is not opened, it will be used up within half a year, and the vacuum packaging is opened within 24 hours, and the temperature and humidity are controlled. In the environment, the board should be used within the next year if it is not unpacked. If it is disassembled, the film should be pasted within an hour within a week. The temperature and humidity should also be controlled. The gold board is equivalent to the tin board, but the control process is stricter than that of the tin board.