In the development process of the copper clad laminate industry in the past ten years, it has experienced several major and far-reaching technological transformations and upgrades. “Lead-free and halogen-free” and “high frequency and high speed” driven by communication technology upgrades, the first two technology conversions have already occurred and have had an impact on the industry structure and have continued to play a crucial role, and the latter is exerting an impact with the progress of 5G communication.
CCL industry develops toward “lead-free and halogen-free” under environmental protection requirement
With the gradual penetration of electronic products into all aspects of people’s daily work and life, and the increasing awareness of green environmental protection worldwide, the environmental protection requirements of the electronics industry have also increased accordingly.
Since July 2006, the European Union has begun to fully implement two directives (RoHS, WEEE), clearly listing 6 substances including lead, polybrominated biphenyls and polybrominated diphenyl ethers (bromine is a halogen element) as hazardous substances and restricting their use. It has received positive responses from different countries and regions around the world. Under its influence, environmentally friendly copper clad laminates that adapt to lead-free processes and are halogen-free have developed rapidly.
Adapting to the lead-free process poses a higher challenge to the heat resistance and reliability of the copper clad laminate, because the melting point of the lead-free solder paste is higher, and the copper clad laminate needs to withstand the higher temperature of the soldering process. Halogen-free means that a new type of halogen-free flame retardant needs to be used, and the resin formulation system needs to be adjusted to achieve the balance and optimization of the performance of the copper clad laminate.
Increased circuit integration and miniaturized smart terminals drive the “thinning” of the CCL industry
For half a century, chip technology has developed rapidly in accordance with Moore’s Law, and the degree of circuit integration has been continuously improved. Consumer electronics products like smart phones and wearable devices are further miniaturized, high-precision and multi-functional.
Under this trend, as the carrier of the circuit, the printed circuit board needs to meet the requirements of high-density interconnection, which stimulates the copper clad laminate demands. That is, the substrate must be light and thin and have strong processing performance to meet the requirements of multi-layer PCB or HDI PCB.
On the one hand, the thinning of copper clad laminates has extremely high requirements on the production process, which is mainly reflected in the control of the gluing link, the high purity and impurity control of the production process, the control of the flatness and dimensional stability of the substrate. On the other hand, in order to maintain or even improve performance while pursuing on thinning size, it is often supplemented with filler technology or blended resin formulations to enhance the performance of copper clad laminates in a targeted manner to meet the needs of end applications.
Upgrading communication technology promotes the “high frequency and high speed” of the CCL industry
- Communication technology has been upgraded, and communication frequency and transmission rate have been greatly improved.
Mobile communication is one of the most dynamic development fields in the global information industry today. The number of global mobile communication users has continued to grow, which has greatly driven the rapid development of communication system equipment and related materials industries. Mobile communication technology undergoes a major technological upgrade every ten years or so, and the transmission rate and frequency are greatly improved after each technological upgrade. In the 5G era, the communication frequency has risen to the frequency band above 5GHz or 20GHz, and the transmission rate has reached above 10-20Gbps.
2. High frequency and high speed greatly increase the electrical performance requirements of the copper clad laminate industry.
In traditional electronic product applications, most of the application frequencies are concentrated below 1GHz, and the electrical properties of ordinary copper clad laminates are sufficient to meet their requirements. However, they are often ignored by designers of PCB manufacturers. While under the high-frequency and high-speed environment, the attenuation of the high-frequency signal itself is very serious. Its transmission in the medium will be affected and limited by the characteristics of the copper clad laminate itself, which will cause signal distortion or even loss. Therefore, high-frequency and high-speed applications have very high requirements for the electrical performance of copper clad laminates.
In order to solve the demand for high frequency and high speed, and to deal with the problems of poor penetration and fast attenuation of high frequency signals, the main requirements of 5G communication equipment for the electrical performance of copper clad laminates are low dielectric constant (Dk) and low dielectric loss factor (Df). The industry divides copper-clad laminates into six grades according to dielectric loss factor(Df). The higher the transmission rate, the lower the required Df value. Taking 5G communication as an example, its theoretical transmission speed is 10-20Gbps, and the dielectric loss performance of the corresponding copper-clad laminate must be at least medium-low loss level. The lower the Df, the more technically difficult the material.