Lead-tin boards are needed in many products, especially PCB multilayer board with many varieties and small quantities. If the hot air leveling process is used, the manufacturing cost will be increased, the processing cycle will be long, and the construction will be very troublesome. For this reason, lead-tin plates are usually used in manufacturing, but there are more quality problems during processing. The biggest quality problem is PCB delamination and blistering. What are the reasons? Cause of:

Causes of PCB quality problems

1. Improper suppression causes air, moisture and pollutants to enter;

2. During the pressing process, due to insufficient heat, too short cycle, poor quality of the prepreg, and incorrect function of the press, resulting in problems with the degree of curing;

3. Poor blackening treatment of the inner line or the surface is polluted during blackening;

4. The inner ply or prepreg is contaminated;

5. Insufficient glue flow;

6. Excessive glue flow-almost all glue contained in the prepreg is extruded out of the board;

7. In the case of non-functional requirements, the inner layer board should minimize the appearance of large copper surfaces (because the bonding force of the resin to the copper surface is much lower than the bonding force of the resin and the resin);

8. When vacuum pressing is used, the pressure is insufficient, which will damage the glue flow and adhesion (the residual stress of the multilayer board pressed by the low pressure is also less).

For thinner films, because the overall amount of glue is small, the problem of insufficient regional resin is more likely to occur, so the use of thin films must be handled carefully. At present, the proportion of thin plates is getting higher and higher. In order to maintain the stability of the thickness, the formulations of the base material factories are adjusted to the direction of relatively low flow. In order to improve the physical properties of the materials, different fillers are added to the resin formulations. During the operation of the substrate, avoid the colloid falling during the operation, which may cause the problem of air bubbles on the bottom plate caused by the thin resin or cream layer.