Introduction to High Density Printed Circuit Board

Printed circuit boards are structural components formed by insulating materials supplemented by conductor wiring. When making the final product, integrated circuits, transistors, diodes, passive components, and various other electronic components are installed on it. By connecting wires, electronic signal connections and functions can be formed. Therefore, printed circuit boards are a platform that provides component connections, serving as the foundation for connecting components.

Due to the fact that printed circuit boards are not general end products, the definition of their names is somewhat confusing. For example, motherboards used in personal computers are called motherboards and cannot be directly referred to as printed circuit boards. Although there are boards in motherboards, they are not the same. Therefore, when evaluating the industry, it cannot be said that the two are related but cannot be said to be the same. For example, because there are integrated circuit parts loaded on the circuit board, the news media refers to it as an IC board, but in essence, it is not equivalent to a printed circuit board.

With the trend of multifunctional and complex electronic products, the contact distance of integrated circuit components is reduced, and the speed of signal transmission is relatively increased. This leads to an increase in the number of connections and a localized reduction in the length of inter point wiring. These require the application of high-density wiring configuration and micropore technology to achieve the goal. Wiring and bridging are basically difficult to achieve for single and double-sided boards, resulting in printed circuit boards becoming more multi-layer. Additionally, due to the continuous increase of signal lines, more power layers and ground planes are necessary means of design, all of which make layer printed circuits more common.

For the electrical requirements of high-speed signals, printed circuit boards must provide impedance control with AC characteristics, high-frequency transmission capability, and reduce unnecessary radiation (EMI). Adopting the structure of stripline and microstrip, multi-layer design becomes necessary. In order to reduce the quality problem of signal transmission, low dielectric will be adopted. In order to meet the miniaturization and array of electronic components, the density of printed circuit boards will also be continuously increased to meet the demand. The emergence of assembly methods for components such as BGA, CSP, and DCA (Direct Chip Attachment) has further promoted printed circuit boards to unprecedented high-density levels.

Holes with a diameter less than 150um are referred to as micropores in the industry. Circuits made using the geometric structure technology of these micropores can improve the efficiency of assembly, space utilization, and other aspects. At the same time, it is also necessary for miniaturization of electronic products.

There have been multiple different names in the industry for printed circuit board products with this type of structure. For example, European and American companies used to refer to these types of products as SBUs due to the use of sequential construction methods in their programs, which is generally translated as "sequential layering method". As for Japanese manufacturers, because the pore structure produced by these products is much smaller than in the past, the production technology of these products is called MVP. Some people also refer to traditional multilayer boards as MLB (Multilayer Board), so they refer to these types of printed circuit boards as BUM.

The IPC Circuit Board Association in the United States, based on the consideration of avoiding confusion, proposed to refer to this type of product as the universal name for HDI. If translated directly, it would become high-density connection technology. However, this cannot reflect the characteristics of printed circuit boards, so most pcb manufacturers refer to such products as HDI boards or the full Chinese name "high-density interconnect technology". However, due to the issue of smooth spoken language, some people directly refer to such products as "high-density circuit boards" or HDI boards.