PCB Technical - What is the lamination of a pcb board?

The production process of ordinary PCB is relatively simple, and the production process of PCB multilayer circuit board is relatively complicated. In the production process of multilayer PCB, there is a step called lamination. How is lamination done? Changbo Technology is here to analyze with you!

The main content of PCB multilayer lamination:

Laminating is the process of bonding each layer of circuits into a whole by means of a stage prepreg. This bonding is achieved through mutual diffusion and penetration between macromolecules at the interface, and then interweaving. The process of bonding the various layers of circuits into a whole by the stage prepreg. The purpose of doing so in the PCB board process is to press the discrete multi-layer board together with the adhesive sheet into a multi-layer board with the required number of layers and thickness.

1. Typesetting is to superimpose materials such as copper foil, bonding sheet (prepreg), inner layer board, stainless steel, isolation board, kraft paper, outer layer steel plate, etc. according to the process requirements. If the board is more than six layers, pre-typesetting is required.

2. During the PCB lamination process, the stacked circuit boards are sent to the vacuum heat press. The heat energy provided by the machine is used to melt the resin in the resin sheet, thereby bonding the substrate and filling the gap.

3. Laminating For designers, the first thing to consider for laminating is symmetry. Because it will be affected by pressure and temperature during the lamination process, there will be stress in the board after the lamination is completed. Therefore, if the two sides of the laminated PCB board are not uniform, the stress on the two sides will be different, causing the board to bend to one side, which greatly affects the performance of the PCB board.

Even in the same plane, if the distribution of copper is not uniform, the resin flow speed at each point will be different, so that the thickness of the PCB board with less copper will be slightly thinner, and the thickness of the place with more copper will be slightly thicker. . In order to avoid these problems, in the design, the uniformity of the copper distribution, the symmetry of the laminate, the design and layout of the blind and buried vias, etc., need to be carefully considered.