PCB Technical - HDI board application and processing technology

HDI board that is high-density interconnection board, is a circuit board with a relatively high line distribution density using micro-blind and buried via technology. It contains inner and outer circuits, and then uses drilling and metallization processes in the holes to realize the connection function between the inner layers of the circuits. With the development of electronic products to high density and high precision, the same requirements are put forward on circuit boards accordingly. The most effective way to increase the PCB density is to reduce the number of through holes, and accurately set blind holes and buried holes to achieve this requirement, which resulted in HDI boards. The AET-PCB section will be divided into the engineering design, material selection, processing technology,

1. concept

HDI: High Density Interconnection Technology. It is a multilayer board manufactured by the build-up method and micro-blind buried vias.

Micro-holes: In the PCB, holes with a diameter of less than 6mil (150um) are called micro-holes.

Buried Via Hole: Buried Via Hole, a hole buried in the inner layer, which is not visible in the finished product. It is mainly used for the conduction of the inner layer line, which can reduce the probability of signal interference and maintain the continuity of the characteristic impedance of the transmission line. Since buried vias do not occupy the surface area of the PCB, more components can be placed on the surface of the PCB.

Blind Via: Blind Via, a via hole that connects the surface layer and the inner layer without going through the entire page.

2. Process flow

High-density interconnection technology can currently be divided into a first-order process: 1+N+1; a second-order process: 2+N+2; and a third-order process: 3+N+3.