Because P or N uses P or N to replace halogen atoms, the polarity of the molecular key segment of epoxy resin to a certain extent, thereby improving the insulation resistance and anti -breakdown ability.

1) Water absorption of materials

Because the loneliness of N and P in the oxygen resin in the nitrogen -free plate is relatively less than the halogen of N and P in the oxygen resin, the probability of forming hydrogen bonds with hydrogen atoms in the water is lower than that of halogen materials, so the water absorption of its materials is lower than that Conventional halogen system flame retardant materials.

For board, low water absorption has a certain effect on improving the reliability and stability of the material.

2) Thermal stability of the material

The content of nitrogen and phosphorus in halogen -free plates is greater than the content of halogen of ordinary halogen materials, so its single molecular weight and TG value have increased. In the case of heating, its molecular exercise ability will be lower than the conventional epoxy resin, so the thermal expansion coefficient of halogen -free materials is relatively small.

Compared to halogen -free plates, halogen -free plate has more advantages. The replacement of halogen -free plates is also a general trend.

The layer pressure parameters may be different because the plates of different companies may be different. Take the Shengyi substrate and PP as a multi-layer board mentioned above, in order to ensure the full flow of the resin, make the combination of good combination, and require lower the heating rate (1.0-1.5 ° C / min) and multi-paragraph The pressure is coordinated, and the time is required for a long time during the high temperature stage, and 180 ° C is maintained for more than 50 minutes.

Here are the recommended sets of boarding program settings and the actual heating of the plate. The binding force of the pressed plate to detect its copper foil and the substrate is 1.ON / MM. The plates after the picture have no layering and bubbles after six thermal shocks.

3) Drilling processability

Drilling conditions are an important parameter that directly affects the quality of the hole wall of PCB during processing. Since the use of the P and N series of official energy groups increase the molecular weight, the molecular bonds are used to enhance the rigidity of the molecular bond. Therefore, the rigidity of the material is also enhanced.

At the same time, the TG points of halogen-free materials are generally higher than that of ordinary copper-covered plates. Therefore, the drilling parameters of ordinary FR-4 are used for drilling. The effect is generally not ideal. When drilling without halogen, it is necessary to make some adjustments under normal drilling conditions.

4) resistance to resistance

Generally, halogen-free plates are worse than ordinary FR-4, so in the etching process and after welding, you should pay special attention to the soaking time in the alkaline retirement fluid. To prevent the occurrence of substrate white spots.