PCB Blog - Five types of PCB board improve the level of CCL technology

The key tasks of my country's copper-clad laminate (CCL) industry in the future development strategy, specifically in terms of products, should be made on five types of new substrate materials for PCB board, that is, through the development of five types of new substrate materials and technological advancement. The breakthrough has improved the technology of my country's CCL. The development of these five types of new high-performance CCL products listed below is a 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 CCL

At the EU meeting on October 11, two "European Directives" with environmental protection content were adopted. They will be fully implemented on July 1, 2006. The two "European Directives" refer to the "Waste Electrical and Electronic Products Directive" (WEEE for short) and the "Restriction of the Use of Certain Hazardous Substances" (RoHS for short). The use of lead-containing materials is prohibited, so the development of lead-free copper-clad laminates as soon as possible is the way to deal with these two directives.

High-performance copper-clad laminate

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 PCB boards, and high heat-resistance copper-clad laminates, and various substrate materials (resin-coated laminates) for multi-layer laminates. Copper foil, organic resin film that constitutes the insulating layer of the laminated multilayer board, glass fiber reinforced or other organic fiber-reinforced prepreg, etc.). In the next few years (until 2010), in the development of this type of high-performance copper clad laminate, according to the forecast of the future development of electronic installation technology, the corresponding performance index values should be achieved.

Substrate material for IC package carrier

The development of substrate materials for IC package carriers (also known as IC package 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 in the direction of high frequency and low power consumption, IC packaging substrates will be improved in important properties such as low dielectric constant, low dielectric loss factor, and high thermal conductivity. An important subject of future research and development is the thermal connection technology of the substrate - effective thermal coordination and integration of heat dissipation, etc. In order to ensure the freedom of IC packaging design and the development of new IC packaging technologies, it is essential to carry out model tests and simulation tests. These two tasks are of great significance for mastering the characteristic requirements of the substrate material for IC packaging, that is, its electrical performance, heat generation and heat dissipation performance, reliability, and other requirements. In addition, there should be further communication with the design industry of IC packaging to reach a consensus. The properties of the developed substrate materials are provided to the designer of the complete electronic product in time so that the designer can establish an accurate and advanced data foundation. The IC package carrier also needs to solve the problem of inconsistency in the thermal expansion coefficient with the semiconductor chip. Even in a build-up multilayer board suitable for microcircuit fabrication, there is a problem that the thermal expansion coefficient of the insulating substrate is generally too large (generally, the thermal expansion coefficient is 60 ppm/°C). The thermal expansion coefficient of the substrate is 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. To this end, a new generation of printed circuit boards that transcend the boundaries of traditional substrate materials and traditional manufacturing processes is predicted to appear in the world around 2005. The breakthrough in technology is first of all a breakthrough in the use of new substrate materials.

Predicting the future development of IC packaging design and manufacturing technology, there are stricter requirements for the substrate materials used in it. This is mainly manifested in the following aspects:

1) High Tg properties corresponding to lead-free fluxes.

2) To achieve a low dielectric loss factor that matches the characteristic impedance.

3) Low dielectric constant (ε should be close to 2) corresponding to high speed.

4) Low warpage (improvement of the flatness of the substrate surface).

5) Low moisture absorption.

6) Low thermal expansion coefficient, making the thermal expansion coefficient close to 6ppm.

7) The low cost of IC package carrier board.

8) Low-cost substrate material for built-in components.

9) In order to improve the thermal shock resistance, the basic mechanical strength is improved. The substrate material is suitable for high to low-temperature cycling without degrading performance.

10) To achieve low cost, the green substrate material is suitable for high reflow temperature. The special-function CCL referred to here mainly refers to metal-based (core) CCL, ceramic-based CCL, high-dielectric constant board, and CCL (or substrate material) 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 laminate are not only the need for the development of new technologies for electronic information products but also the need for the development of my country's aerospace industry.

High-performance flexible copper-clad laminate

Since the large-scale industrial production of flexible printed circuit boards (FPC), 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, the FPC without adhesive (generally referred to as "two-layer FPC") appeared. In the 1990s, the world developed a photosensitive cover film corresponding to high-density circuits, which made a great change in the design of FPC. Due to the opening of new application fields, the concept of its product form has undergone a lot of changes, and it has been extended to a larger range including substrates for 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 pattern has developed rapidly 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 reaches about 3 billion to 3.5 billion US dollars. In recent years, the world's production of FPC has been increasing. Its proportion in the PCB board is also increasing year by year. In the United States, China, and other countries, the proportion of FPC in the output value of the entire printed circuit board has now reached 13%-16%. FPC has increasingly become a very important and indispensable variety in PCB boards. In terms of flexible copper-clad laminates, there is a big gap between China and the advanced countries and regions in the world in terms of production scale, manufacturing technology level, and raw material manufacturing technology. This gap is even larger than that of rigid copper-clad laminates.

Copper clad laminates should develop synchronously with PCB boards

Copper clad laminate (CCL), as the substrate material in PCB manufacturing, mainly plays the role of interconnection, insulation, and support for the PCB, and has a great impact on the transmission speed, energy loss, and characteristic impedance of signals in the circuit. Therefore, the performance, quality, processability in manufacturing, manufacturing level, manufacturing cost, long-term reliability, and stability of the PCB board largely depend on the CCL material. The technology and production of CCL have gone through more than half a century of development. Now the annual output of CCL in the world has exceeded 300 million square meters. CCL has become an important part of 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. The development of electronic information technology shows that copper-clad laminate technology is one of the key technologies to promote the rapid development of the electronic industry. The development of CCL technology and production is synchronized and inseparable from the development of the electronic information industry, especially the PCB industry. This is a process of continuous innovation and continuous pursuit. The progress and development of CCL are constantly driven by the innovation and development of electronic complete machine products, semiconductor manufacturing technology, electronic installation technology, and PCB board manufacturing technology. The rapid development of the electronic information industry makes electronic products develop in the direction of miniaturization, functionalization, high performance, and high reliability. From the general surface mount technology (SMT) in the mid-1970s to the high-density interconnect surface mount technology (HDI) in the 1990s, and the application of various new packaging technologies such as semiconductor packaging and IC packaging technology in recent years, Electronic installation technology continues to develop in the direction of high density. At the same time, the development of high-density interconnection technology promotes the development of PCB boards in the direction of high density. The development of installation technology and PCB board technology has made the technology of copper clad laminate, which is the substrate material of PCB board, constantly improving. It is predicted that the average annual growth rate of the world electronic information industry in the next 10 years will be 7.4%. By 2010, the world electronic information industry market will reach 3.4 trillion US dollars, of which electronic equipment will be 1.2 trillion US dollars, and communication equipment and computers will account for it. more than 70% of the total, reaching 0.86 trillion US dollars. It can be seen that the huge market of copper-clad laminates as electronic basic materials will not only continue to exist but also continue to develop at a growth rate of 15%. The relevant information released by the CCL Industry Association shows that in the next five years, in order to adapt to the development trend of high-density BGA technology and semiconductor packaging technology, the proportion of high-performance thin FR-4 and high-performance resin substrates will be increasing in the PCB board.