PCB provides interconnection and signal transmission between electronic products. Technological progress promotes the development of smart phones and other 3C electronic devices in the direction of thinness, miniaturization and action. In order to achieve the goal of less space, faster speed and higher performance, the requirements of "light, thin, short and small" for PCB are constantly improved. PCB provides electronic interconnection, downstream demand drives PCB growth, PCB provides interconnection and signal transmission between electronic products. It is a key interconnection component for assembling electronic parts. It not only provides electrical connection for electronic components, but also carries the business functions of digital and analog signal transmission, power supply and RF and microwave signal transmission and reception of electronic equipment. Most electronic equipment and products need to be equipped with. The manufacturing quality of PCB not only directly affects the reliability of electronic products, but also affects the integrity of signal transmission between chips.

The demand of seven major fields drives the growth of PCB. The terminal demand of printed circuit board can be divided into enterprise user demand and individual consumer demand. Among them, the demand of enterprise level users is mainly concentrated in the fields of communication equipment, industrial control and medical treatment, aerospace and other fields. The related PCB products often have the characteristics of high reliability, long service life and strong traceability, so the qualification certification of corresponding PCB enterprises is stricter and the certification cycle is longer; The demand of individual consumers is mainly concentrated in the fields of computer, mobile terminal and consumer electronics. The related PCB products usually have the characteristics of thinness, miniaturization and flexibility, and the terminal demand is large, which requires the corresponding PCB enterprises to have the capacity of mass supply.

PCB is developing towards "light, thin, short and small". Technological progress promotes the continuous development of smart phones and other 3C electronic equipment in the direction of thinness, miniaturization and action. In order to achieve the goal of less space, faster speed and higher performance, the requirements of "light, thin, short and small" for PCB are constantly improved.

PCB line width is evolving towards smaller size and higher integration. In particular, with the increasing functions of smart electronic terminals such as mobile phones, the number of I / O is also increasing, and the line width and line spacing must be further reduced. However, due to the limitation of traditional HDI process, SLP (substrate like PCB) technology with more stack layers, smaller line spacing and more function modules becomes the inevitable choice to solve this problem.

SLP has smaller linewidth than HDI. SLP is high-order HDI. It mainly uses half addition technology, which is between subtraction method and full addition method. Compared with the full addition method, SLP is more mature, and the refinement and reliability of graphics can meet the needs of high-end products, and can be used for batch production. The semi addition process is suitable for fine line spacing between 10 / 10-50 / 50 μ M. As an optimized product that can meet the requirements of mobile phone space and signal transmission at the same time, the gradual mass production and promotion of SLP will break the industry ecology.