How to determine how many orders there are in blind/buried via HDI PCB Board

Blind/buried HDI (High Density Interconnect) board is an advanced printed circuit board technology that uses tiny blind and buried vias to increase the wiring density on the circuit board. This technology is particularly suitable for application scenarios that require high integration and limited space, such as portable electronic devices such as smartphones and tablets.

Blind vias refer to through-holes that only connect the outer layer to one or more adjacent inner layers, and do not penetrate the entire circuit board.
Buried vias are completely located inside the circuit board and are used to connect two or more inner layers. They are invisible from the outside.
The use of blind/buried via design can achieve a more detailed circuit layout and reduce the length of the signal transmission path, which helps to improve signal integrity and reduce electromagnetic interference. Blind/buried via HDI boards can be drilled mechanically or by laser, depending on design requirements and manufacturing capabilities.
There are many types of blind/buried via HDI boards, and the industry uses the number of orders to distinguish them. Simply put, "order" means a order. The previous step is the first order, and the previous two steps are the second order. Then the blind/buried via HDI board is understood as a laser-drilled HDI board with one laser for the first order, two lasers for the second order, and mechanical blind/buried via drilling to connect one core board is the first order, and connecting two core boards is the second order.

Definition of "order" of blind/buried via HDI board

Generally, HDI boards are named with a+N+a, a+N+N+a structures, where a represents build-up layer, one build-up layer is first order, two build-ups are second order, and three build-ups are third order; N represents core layer. Common structures include: 1+N+1, 1+N+N+1, 2+N+2, 2+N+N+2, 3+N+3, 3+N+N+3, etc.

Definition of "Times" of Blind/Buried Via HDI Boards
In the lamination structure of blind/buried via HDI boards, the sum of the number of mechanical blind/buried via drilling and the number of laser blind/buried via drilling (if both sides need laser drilling after lamination, it will be counted as two blind/buried vias. However, when calculating the drilling price, only the total number of holes drilled by one laser or the minimum consumption of one drilling is counted).

Examples of "Order" and "Times" in Blind/Buried Via HDI PCBs

1. Structure diagram of bidirectional build-up stacked blind/buried via HDI board with pure laser drilling.

2. Simple hybrid bidirectional build-up blind/buried via HDI board structure diagram (laser blind via is stacked via)

3. Simple hybrid bidirectional build-up blind/buried via HDI board structure diagram (laser blind via is a staggered hole)

4.Complex hybrid bidirectional build-up blind/buried via HDI board structure (laser blind vias have both stacked and staggered

vias)

5. Structure diagram of blind/buried hole times of pure mechanical drilling

6. Dual-core bidirectional layer-added blind/buried hole order structure diagram for pure mechanical drilling (including false layer design)

7. Dual-core unidirectional layer-adding blind/buried hole order structure diagram of pure mechanical drilling

8. Dual-core unidirectional layer-adding blind/buried hole order structure diagram of pure mechanical drilling

9. Complex hybrid bidirectional build-up blind buried/hole plate structure Figure 1

10. Complex hybrid bidirectional build-up blind/buried via board structure diagram 2

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