Characteristics analysis and technical principles of MPI high-frequency copper-clad laminates

    copper clad laminateIt refers to a laminated board formed by applying a layer of resin between the copper foil layer and the glass fiber cloth after high-temperature treatment of copper foil. During this process, the resin coated on the surface of the copper foil can be fluorinated polyamide acid resin (FPAC), polyimide (PI), or polytetrafluoroethylene (PTFE), etc., which can form good adhesion with the copper foilCopper clad foilA very thin and uniform protective film layer is formed on the surface.

High frequency board is mainly used in products such as mobile phones, computers, communications, radios, and televisions. The characteristics it requires are:
(1) Lightweight. In order to reduce the weight of PCBs, lower production costs, and improve product performance, methods such as reducing insulation thickness and minimizing material usage are often used in the manufacturing process of PCBs.

(2) Good heat resistance. The production process of PCB is carried out at high temperatures. If the surface temperature is high, the protective film layer formed on the copper-clad laminate is not easily removed, which reduces its insulation performance. Therefore, The surface temperature of PCB substrate should be relatively low, usually below 75 ℃.

(3) No pollution to the environment.

MPI high-frequency copper-clad laminates have the following characteristics:

(1) Due to the protection of FPC insulation paper, the product does not require special treatment during transportation and installation;

(2) During the production of MPI high-frequency boards, there is no solvent evaporation, which avoids secondary pollution;

(3) Due to its excellent heat resistance and high temperature resistance, it solves the problem of FPC being prone to brittleness and aging;

(4) MPI high-frequency board has high bonding strength, good tensile strength, and bending performance;

(5) Due to the use of glass fiber cloth as the outer layer instead of pure copper foil for MPI high-frequency boards.

1、 Overview

    MPI high-frequency copper-clad laminateIt refers to a copper-clad laminate with high-frequency performance made by using glass fiber cloth as the matrix, subjecting glass fiber cloth with low dielectric constant (Lr) to thermal induced phase change treatment, and then hot pressing at high temperature. The research on MPI high-frequency copper-clad laminates began in the early 1970s and successfully produced the world's first MPI high-frequency copper-clad laminate in the early 1980s. Since then, the research on MPI high-frequency copper-clad laminates has developed rapidly.

2、 Development of MPI substrate technology

With the development of electronic products towards miniaturization and intelligence, MPI, as a PCB substrate material, has been widely used in consumer electronics products, and its advantages are constantly increasing. However, traditional MPI substrates, due to their poor heat resistance, low strength, poor insulation, and high cost, are difficult to meet market demand and have begun to develop towards high-performance, lightweight, and low-cost directions.

3、 MPI process principle

The main process principle of MPI copper-clad laminate is to arrange glass cloth at certain intervals, coat it with a layer of polyester resin, and then treat it at high temperature (above 200 ℃) to cure the glass cloth. Then place the glass cloth on the copper foil treated at high temperature (above 200 ℃), and evenly coat the surface of the copper foil with a layer of polyester resin. Remove the gap between the glass cloth and heat it to cure it.MPI copper-clad laminateLike FPC insulation paper, polyester resin is used as the adhesive. It has the characteristics of high bonding strength, good heat resistance, low coefficient of thermal expansion, and thin thickness.

4、 Characteristics of MPI

MPI has excellent electrical performance: high temperature resistance, wide temperature range, low water absorption, small coefficient of thermal expansion, good dimensional stability, and good low-temperature impact toughness. MPI can work for a long time at high temperatures: it can withstand temperatures up to 150 ℃ and can work for a long time at temperatures up to 200 ℃. Can maintain stability and prevent brittle fracture during high and low temperature impact testing; MPI has excellent mechanical properties: strong flexural resistance, no cracking, no delamination, and no delamination phenomenon; MPI has good chemical stability: it can withstand acid, alkali, salt spray corrosion, and strong oxidants. MPI also has good electrical performance: low dielectric loss and low dielectric constant; MPI can adapt well to the transmission of high-frequency (HF, UHF) signals. MPI has excellent insulation and printing performance: it can be used at high temperatures.

5、 Conclusion

MPI high-frequency board, as a new product, is a multifunctional and high-performance copper-clad board produced by special processes on the basis of glass fiber cloth and resin. It not only meets the high-density and multifunctional requirements of PCB, but also has the characteristics of light weight, high heat resistance, and no pollution to the environment. Especially, it has good bonding strength and excellent bending performance, which cannot be compared to ordinary copper-clad laminates.MPI high-frequency boardIt has a wide range of applications and is widely used in fields such as communication equipment, automotive electronics, and household appliances. Due to the outstanding advantages of MPI high-frequency boards, their production scale is expanding year by year. With the increasing demand for product miniaturization, lightweight, and high reliability in the electronics industry, MPI high-frequency board will become a mainstream product and will be applied in more fields.