Five major application technologies of silicon micropowder for copper clad laminates
At present, the inorganic fillers used in copper clad laminates (CCL) mainly include the following types: ATH (aluminum hydroxide), talc powder, silicon micropowder, kaolin, calcium carbonate, titanium dioxide, insulating whiskers, zinc molybdate coating Inorganic fillers, layered clay minerals, etc. Among them, the most widely used inorganic filler is silica powder.
Silica powder, which is widely used in the CCL industry as an inorganic filler, can be divided into three types: molten type, crystalline type, and composite type from the molecular structure; from the powder particle morphology, it can be divided into two types: angular shape and spherical shape. Compared with angular silica powder, spherical silica powder has greater advantages in terms of filling, thermal expansion, and abrasiveness.
On the whole, the application technology of silica powder filler can be summarized into the following five aspects:
1. Oriented to improve the performance of the plate
The rapid iteration of electronic products has put forward higher performance requirements for PCB boards. As a functional filler, silicon micropowder filler can improve multiple performances of copper clad laminates, and can also reduce manufacturing costs. It has attracted more and more attention and is widely used.
2. Optimize the particle size and particle size distribution of silica powder
The particle size of the filler varies in the application process. There are two important indicators for the filler particles, one is the average particle size, and the other is the particle size distribution. Studies have shown that the average particle size and particle size distribution range of fillers have a very important impact on the filling effect and the comprehensive performance of the board.
3. Preparation and application of spheroidization
The preparation methods of spherical silicon micropowder include: high-frequency plasma method, direct current plasma method, carbon electrode arc method, gas combustion flame method, high-temperature melt spray granulation method and chemical synthesis method, among which the preparation method with the most industrial application prospect Is the gas combustion flame method.
The shape of microsilica powder directly affects its filling amount. Compared with angular silica powder, spherical silica powder has higher bulk density and uniform stress distribution, so it can increase the fluidity of the system, reduce the viscosity of the system, and also has a larger surface area.
4. High filling technology
If the amount of filler is too low, the performance cannot meet the requirements, but with the increase of the amount of filler, the viscosity of the system will increase sharply, the fluidity and permeability of the material will become poor, and the dispersion of spherical silica powder in the resin will be difficult, and agglomeration will easily occur.
5. Surface modification technology
Surface modification can reduce the interaction between spherical silica powder, effectively prevent agglomeration, reduce the viscosity of the whole system, improve the fluidity of the system, and strengthen the spherical silica powder and PTFE (polytetrafluoroethylene) resin matrix. Excellent compatibility, so that the particles are evenly dispersed in the glue.
In the future, the preparation technology of spherical silica powder, high filling technology and surface treatment technology will still be an important development direction of silica powder filler. Study the preparation technology of spherical silica powder to reduce the production cost and make it more widely used. When the filling amount is not enough to meet the higher and higher performance requirements, the research on high filling technology is imperative. Surface treatment technology is very important in the field of inorganic fillers for CCL. Various coupling agents researched and applied at this stage can improve the performance to a certain extent, but there is still a lot of room for it.
In addition, the research and application of inorganic fillers for CCL will also move from the application of single fillers to the research and application of mixed fillers, in order to improve multiple properties of CCL at the same time.