PCBs with buried and blind vias are not all HDI PCB. HDI PCB generally have blind vias, but buried vias are not the case. It depends on the order and pressure of your product.
The explanation is as follows:
The first and the second of the 6-layer PCB are for wrenches that require laser drilling, that is HDI PCB.
6-layer first-order HDI PCB 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 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, continue to press 2-5, then drill 2-3, 4-5 laser holes for the first time, continue to press 1-6 for the second time, and then drill 1-2, 5 for the second time The -6 laser hole was finally drilled through the hole. It can be seen that the second-order HDI PCB has passed two pressing and two laser drilling.
Additional second-order HDI PCB are also divided into: second-order HDI PCB with wrong holes and second-order HDI PCB with stacked holes. The second-order HDI PCB with wrong holes mean that the blind holes 1-2 and 2-3 are mutually separated, and the stacked holes Step HDI PCB 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...all the same.
ipcb As a professional PCB supplier, we focus on high-precision double / multi-layer PCB Factory, HDI PCB, thick copper plate, blind hole PCB, high-frequency circuit PCB manufacturing, PCB sample and PCB batch production.