Mobile Phone HDI PCB

A good laminated design can make the PCB performance better. In the current mobile phone market with increasingly fierce competition, cost is undoubtedly an important factor for survival. This is a low-cost mobile phone PCB with a six-layer first-order HDI PCB board traces.The production of the first-order HDI PCB board is relatively simple, the process and process are well controlled, and the cost is the lowest.

The legend of the first-order mechanical blind vias (the following illustrations are not designed for overlapping holes)

first-order mechanical blind vias

HDI: short for high Density interconnection, high-density interconnection, non-mechanical drilling, micro-blind via hole ring below 6mil, wiring width between inner and outer layers. The build-up multi-layer board manufacturing method with the line gap below 4mil and the pad diameter not greater than 0.35mm is called HDI PCB.

How to define a few levels of HDI PCB board

Blind vias: short for Blind via, which realizes the connection and conduction between the inner layer and the outer layer.

Buried vias: short for Buried via, which realizes the connection between the inner layer and the inner layer and the blind hole is large.

Blind vias are small holes with a diameter of 0.05mm~0.15mm. The buried blind holes are formed by laser drilling, plasma etching and photo-induced drilling. Laser drilling is usually used, and laser drilling is divided into CO2 and YAG Ultraviolet laser machine (UV).

The first order and the second order of the 6-layer PCB board are for PCB boards that need laser drilling, that is, HDI PCB boards.

6-layer first-order HDI PCB board refers to blind holes: 1-2, 2-5, 5-6. That is, 1-2, 5-6 need laser drilling.

6-layer second-order HDI PCB board refers to blind holes: 1-2, 2-3, 3-4, 4-5, 5-6. It requires 2 laser drilling. First drill 3-4 buried holes, then press 2-5, then drill 2-3, 4-5 laser holes for the first time, then press 1-6 for the second time, then drill 1-2 for the second time, 5-6 laser holes. Only drill through holes last. It can be seen that the second-order HDI PCB board has been pressed twice and laser drilled twice.

In addition, the second-order HDI PCB board is also divided into: wrong hole second-order HDI PCB board and stacked hole second-order HDI PCB board. The wrong hole second-order HDI PCB board means that the blind holes 1-2 and 2-3 are staggered, and Hole second-order HDI PCB board refers to the blind holes 1-2 and 2-3 stacked together, for example: blind: 1-3, 3-4, 4-6. And so on, third-order, fourth-order. They are all the same .