Introduction to HDI and circuit boards

Under the premise that electronic products tend to be more complex, the contact distance of integrated circuit components is reduced, and the speed of signal transmission is relatively increased, which is followed by an increase in the number of wires and the length of the wires between the points. Localized shortening requires high-density line configuration and micro-hole technology to achieve the goal. Wiring and bridging basically have difficulties for single and double panels, so the circuit board will be multi-layered, and as the signal lines continue to increase, more power layers and ground planes are necessary means of design. These have prompted the Multilayer Printed Circuit Board to become more common.

For the electrical requirements of high-speed signals, the board must provide impedance control with AC characteristics, high-frequency transmission capability, and reduce unnecessary radiation (EMI). With the structure of Stripline and Microstrip, multi-layering becomes a necessary design. In order to reduce the quality of the signal transmission, an insulating material with a low dielectric constant and a low attenuation rate is used. In order to meet the miniaturization and array of the electronic component assembly, the circuit board also continuously increases the density to meet the demand. The emergence of assembly methods such as BGA (Ball Grid Array), CSP (Chip Scale Package), and DCA (Direct Chip Attachment) has pushed printed circuit boards to an unprecedented high-density state.

Where the hole diameter less than 150um is known in the industry as Microvia, the circuit made by the micro-hole geometry technology can improve the efficiency of assembly, space utilization, etc., and also for the miniaturization of electronic products. Its necessity.

For circuit board products of this type, there have been many different names in the industry to call such boards. For example, European and American operators used the sequential construction method because they made the program. Therefore, this kind of product is called SBU (Sequence Build Up Process), and is generally translated as “sequential layering method”. As for the Japanese manufacturer, the hole structure made by this kind of product is much smaller than the previous hole. Therefore, the production technology of this kind of product is called MVP (Micro Via Process), which is generally translated as "microporous process". Some people also call the MUM (Build Up Multilayer Board) because the traditional multi-layer board is called MLB (Multilayer Board), which is generally translated as "layered multi-layer board".

The IPC Board Association of the United States has proposed to refer to this type of product as the common name of HDI (High Density Intrerconnection Technology), and if it is translated directly, it becomes a high-density link technology. However, this does not reflect the board characteristics, so most circuit boards are called HDI boards or the Chinese name "high-density interconnect technology." However, because of the smoothness of spoken language, some people directly call such products "high-density circuit boards" or HDI boards.

The printed circuit board is a structural element formed by an insulating material supplemented by conductor wiring. In the final product, integrated circuits, transistors, diodes, passive components (such as resistors, capacitors, connectors, etc.) and various other electronic components are installed. By connecting wires, electronic signal connections and organic energy can be formed. Therefore, a printed circuit board is a platform that provides component bonding for receiving the base of the component.