HDl belongs to a product of circuit board, the full name is highDensityInterconnection, high-density interconnection board At present, high-end electronic products are generally HDI board products.
Blind vias: Blind vias are a type of via that connects the inner traces of the PCB to the surface traces of the PCB. This hole does not penetrate the entire board.
Buried vias: Buried vias are the type of vias that only connect the traces between the inner layers, so they cannot be seen from the surface of the PCB.
As the design of portable products develops towards miniaturization and high density, the difficulty of PCB design is also increasing, which puts forward higher requirements for the production process of PCB. In most of the current portable products, the BGA package with a pitch of 0.65mm or less uses the design process of blind and buried holes, so what is a blind and buried hole?
Blind vias: Blind vias are a type of via that connects the inner traces of the PCB to the surface traces of the circuit board. This hole does not penetrate the entire board.
Buried vias: Buried vias are the type of vias that only connect the traces between the inner layers, so they cannot be seen from the surface of the PCB.
A circuit board with buried blind holes is not necessarily an HDI circuit board, but generally HDI boards have blind holes, and buried holes are not necessarily the case. It depends on your circuit board products.
described as follows:
The first-order and second-order of the 6-layer circuit board are for boards that require laser drilling, that is, HDI boards.
6-layer circuit board first-order HDI board refers to blind holes: 1-2, 2-5, 5-6. That is, 1-2, 5-6 needs laser drilling.
The second-order HDI board of the 6-layer circuit board refers to blind holes: 1-2, 2-3, 3-4, 4-5, 5-6. It requires 2 times of laser drilling.
