Five major categories of PCB substrates improve CCL technology level

The key tasks of my country’s copper clad laminate (CCL) industry in the future development strategy, specifically speaking, should be to work hard on five major categories of new PCB substrate materials, that is, through the development and technological breakthroughs of the five major categories of new substrate materials, to improve my country’s CCL cutting-edge technology. The development of the five major categories of new high-performance CCL products listed below is the key topic that engineers and technicians in my country’s copper clad laminate industry should pay attention to in future research and development.

Lead-free compatible copper clad laminate

At the EU meeting on October 11, two “European directives” with environmental protection content were passed. They will be formally implemented on July 1, 2006. The two “European directives” refer to the “Waste Electrical and Electronic Products Directive” (abbreviated as WEEE) and the “Restriction of the Use of Certain Hazardous Substances” (abbreviated as RoHs). In these two regulatory directives, it is clearly mentioned that the use of lead-containing materials should be prohibited. Therefore, developing lead-free copper clad laminates as soon as possible is the best way to deal with these two directives.

High-performance copper-clad laminates

The high-performance copper-clad laminates referred to here include low dielectric constant (Dk) copper-clad laminates, copper-clad laminates for high-frequency and high-speed PCBs, high-heat-resistant copper-clad laminates, and various substrate materials for build-up multilayer boards (resin-coated copper foil, organic resin films constituting the insulating layer of build-up multilayer boards, glass fiber reinforced or other organic fiber reinforced prepregs, etc.). In the next few years (until 2010), in the development of this type of high-performance copper-clad laminates, the corresponding performance index values ​​should be achieved based on the predicted development of future electronic installation technology.

Substrate materials for IC packaging substrates

The development of substrate materials for IC packaging substrates (also known as IC packaging substrates) is a very important topic at present. It is also an urgent need for the development of my country’s IC packaging and microelectronics technology. With the development of IC packaging towards high frequency and low power consumption, the IC packaging substrate will be improved in important properties such as low dielectric constant, low dielectric loss factor, and high thermal conductivity. An important topic for future research and development is the effective thermal coordination and integration of thermal connection technology of substrates-heat dissipation.

In order to ensure the freedom of IC packaging design and the development of new IC packaging technology, it is essential to carry out modeling and simulation tests.

These two tasks are very meaningful for understanding and mastering the characteristics of IC packaging substrate materials, that is, understanding and mastering its electrical performance, heat and heat dissipation performance, reliability and other requirements. In addition, further communication should be made with the IC packaging design industry to reach a consensus. The performance of the developed substrate material should be provided to the designers of the whole electronic product in a timely manner so that the designers can establish an accurate and advanced data foundation.

The IC packaging substrate also needs to solve the problem of inconsistent thermal expansion coefficient with the semiconductor chip.

Even for the multilayer board of the build-up method suitable for the production of fine circuits, there is a problem that the thermal expansion coefficient of the insulating substrate is generally too large (generally the thermal expansion coefficient is 60ppm/℃). The thermal expansion coefficient of the substrate reaches about 6ppm, which is close to that of the semiconductor chip, which is indeed a “difficult challenge” for the manufacturing technology of the substrate.

In order to adapt to the development of high speed, the dielectric constant of the substrate should reach 2.0, and the dielectric loss factor can be close to 0.001.

For this reason, a new generation of printed circuit boards that surpass the limits of traditional substrate materials and traditional manufacturing processes is predicted to appear in the world around 2005. The first technological breakthrough is a breakthrough in the use of new substrate materials.

It is predicted that the future development of IC packaging design and manufacturing technology will have more stringent requirements on the substrate materials used.

This is mainly reflected in the following aspects: 1. High Tg corresponding to lead-free solder. 2. Achieve low dielectric loss factor matching the characteristic impedance. 3. Low dielectric constant corresponding to high speed (ε should be close to 2). 4. Low warpage (improvement of the flatness of the substrate surface). 5. Low moisture absorption rate. 6. Low thermal expansion coefficient, making the thermal expansion coefficient close to 6ppm. 7. Low cost of IC packaging carrier. 8. Low-cost substrate material for built-in components. 9. Improvement in basic mechanical strength to improve heat shock resistance. Substrate materials suitable for temperature changes from high to low cycles without reducing performance. 10. Achieve low-cost, green substrate materials suitable for high reflow soldering temperature.

Copper clad laminates with special functions

The copper clad laminates with special functions here mainly refer to: metal-based (core) copper clad laminates, ceramic-based copper clad laminates, high dielectric constant boards, copper clad laminates (or substrate materials) for embedded passive component multilayer boards, copper clad laminates for optical-electrical circuit substrates, etc. The development and production of this type of copper clad laminates is not only a need for the development of new technologies for electronic information products, but also a need for the development of my country’s aerospace and military industries.

High-performance flexible copper clad laminates

Since the large-scale industrial production of flexible printed circuit boards (FPCs), it has experienced more than 30 years of development. In the 1970s, FPC began to enter the real industrialized mass production. In the late 1980s, due to the advent and application of a new type of polyimide film material, FPCs appeared without adhesives (generally referred to as “two-layer FPCs”). In the 1990s, the world developed a photosensitive cover film corresponding to high-density circuits, which made a big change in the design of FPC. Due to the opening of new application fields, the concept of its product form has changed a lot, including expanding it to a wider range of substrates including TAB and COB. The high-density FPC that emerged in the second half of the 1990s began to enter large-scale industrial production. Its circuit graphics have rapidly developed to a more subtle level. The market demand for high-density FPC is also growing rapidly.

At present, the annual output value of FPC in the world has reached about 3 billion to 3.5 billion US dollars. In recent years, the output of FPC in the world has been growing. Its proportion in PCB has also increased year by year. In the United States, Japan and other countries, the proportion of FPC in the output value of the entire printed circuit board has now reached 13%-16%. FPC is becoming more and more a very important and indispensable variety in PCB.

In terms of flexible copper clad laminates, my country has a large gap with the world’s advanced countries and regions in terms of production scale, manufacturing technology level and raw material manufacturing technology. This gap is even greater than that of rigid copper clad laminates.

Expert opinion

Copper clad laminates should develop synchronously with PCBs

As the substrate material in PCB manufacturing, copper clad laminates (CCL) mainly play the role of interconnection, insulation and support for PCBs, and have a great impact on the transmission speed, energy loss, characteristic impedance, etc. of signals in the circuit. Therefore, the performance, quality, processability, manufacturing level, manufacturing cost, and long-term reliability and stability of PCBs depend to a large extent on copper clad laminate materials.

Copper clad laminate technology and production have gone through more than half a century of development.

Now the annual output of copper clad laminates in the world has exceeded 300 million square meters. Copper clad laminates have become an important part of the basic materials in electronic information products. The copper clad laminate manufacturing industry is a sunrise industry. It has broad prospects with the development of electronic information and communication industries. Its manufacturing technology is a high-tech technology that crosses, penetrates and promotes multiple disciplines. The development of electronic information technology shows that copper clad laminate technology is one of the key technologies that promote the rapid development of the electronics industry.

The development of copper clad laminate technology and production is synchronized and inseparable with the development of the electronic information industry, especially the PCB industry.

This is a process of continuous innovation and pursuit.

The progress and development of copper clad laminates are always driven by the innovation and development of electronic complete products, semiconductor manufacturing technology, electronic installation technology, and PCB manufacturing technology.

The rapid development of the electronic information industry has led electronic products to develop in the direction of miniaturization, functionality, high performance, and high reliability. From the general surface mounting technology (SMT) in the mid-1970s to the high-density interconnect surface mounting technology (HDI) in the 1990s, and the application of various new packaging technologies such as semiconductor packaging and IC packaging technology that have emerged in recent years, electronic installation technology has continued to develop in the direction of high density. At the same time, the development of high-density interconnection technology has promoted the development of PCB in the direction of high density. The development of installation technology and PCB technology has also led to the continuous progress of the technology of copper clad laminates as PCB substrate materials.

Experts predict that the average annual growth rate of the world’s electronic information industry in the next 10 years will be 7.4%.

By 2010, the world’s electronic information industry market will reach 3.4 trillion US dollars, of which electronic complete machines will be 1.2 trillion US dollars, and communication equipment and computers will account for more than 70% of it, reaching 0.86 trillion US dollars. It can be seen that the huge market for copper clad laminates, as basic electronic materials, will not only continue to exist, but is also growing at a growth rate of 15%. The relevant information released by the Copper Clad Laminate Industry Association shows that in the next five years, in order to adapt to the development trends of high-density BGA technology and semiconductor packaging technology, the proportion of high-performance thin FR-4 and high-performance resin substrates will increase..