HDI PCB Board Laminate Structure
1. Simple one-layer printed board (one layer of 6 layers at a time, the laminated structure is (1+4+1)). This type of board is the simplest, that is, the inner multi-layer board has no buried holes, and one press is used. Finished, although it is a laminated board, its manufacture is very similar to the conventional multi-layer board one-time lamination, but the subsequent different from the multi-layer board is the need for multiple processes such as laser drilling blind holes. Since the laminated structure has no buried holes, in the fabrication, the second layer and the third layer can be used as one core board, and the fourth layer and the fifth layer are used as another core board, and the outer layer is provided with a dielectric layer and copper. The foil, which is laminated with the dielectric layer in the middle, is very simple and cost less than a conventional primary laminate.
2. Conventional one-layer laminated HDI printed board (primary HDI 6-layer board, stacked structure (1+4+1)) The structure of this type of board is (1+N+1), (N ≥ 2, N even number) , this structure is the mainstream design of a laminated board in the industry at present. The inner multi-layer board has buried holes and needs secondary pressing. This type of 1st laminated board has buried holes in addition to blind holes. If the designer can convert this type of HDI into a simple one-time laminated board of the first type above, both the supply and demand sides It is beneficial. We have a number of customers who have suggested that it is preferable to change the laminated structure of the conventional primary laminate of the second type to a simple primary laminate of the first type.
3. Conventional secondary laminated HDI printed board (secondary laminated HDI 8-layer board, stacked structure is (1++1+4+1+1)) The structure of this type of board is (1+ 1+N+1+1), (N≥2, N even number), this structure is the mainstream design of the secondary layer in the industry. The inner multi-layer board has buried holes, which requires three presses to complete. Mainly there is no stacking design, the production is difficult. If you can change the buried hole of (3-6) layer to the buried hole of (2-7) layer as mentioned above, you can reduce the primary pressing and optimize. The process achieves the effect of reducing costs. This type is like the example below.
4. Another conventional secondary laminated HDI printed board (secondary laminated HDI 8-layer board, stacked structure is (1+1+4+1+1)) The structure of such a board (1 +1+N+1+1), (N≥2, N even), although it is the structure of the secondary laminate, since the position of the buried hole is not between the (3-6) layers, but at (2) -7) Between the layers, this design can also reduce the press-fit once, so that the secondary laminated HDI plate requires 3 press-fit processes and is optimized for the 2-press process. And this type of plate has another difficult place to make, there are (1-3) layer blind holes, split into (1-2) layers and (2-3) layers of blind holes to make, you need to (2 -3) The inner blind hole of the layer is made by filling holes, that is, the inner blind hole of the secondary layer is made by the hole filling process. Generally, the cost of the HDI for making the hole filling process is lower than the cost of not making the hole filling process. High, the difficulty is obviously large, so the conventional secondary laminate, in the design process, it is recommended not to use stacking design, try to convert (1-3) blind holes into staggered (1-2) blind holes and (2-3) Buried (blind) holes. Some sophisticated designers can use this refuge to simplify or simplify the manufacturing costs of their products.
5. Another unconventional secondary laminated HDI printed board (secondary laminated HDI 6-layer board, stacked structure (1+1+2+1+1)) 1+1+N+1+1), (N≥2, N even number), although it is the structure of the secondary laminate, there are also blind holes across the layer, and the depth capability of the blind hole is significantly increased. 3) The blind hole depth of the layer is doubled for the blind hole of the conventional (1-2) layer. The customer of this design has its unique requirements and does not allow the (1-3) cross-layer blind hole to be stacked. Blind hole (1-2) (2-3) blind hole, this kind of cross-layer blind hole is difficult except for laser drilling, and subsequent copper (PTH) and electroplating are also difficult. Generally, PCB manufacturers who do not have a certain level of technology are difficult to manufacture such boards. The difficulty of production is obviously much higher than that of conventional secondary laminates. This design is not recommended unless it has special requirements.
6. The secondary laminated HDI of the blind hole stacking hole design, the blind hole above the buried hole (2-7) layer. (Second laminated HDI 8-layer board, stacked structure is (1+1+4+1+1)) The structure of such a board is (1+1+N+1+1), (N≥2, N even number), this structure is currently a part of the industry's secondary layered board has such a design, the inner multi-layer board has buried holes, need to be completed by secondary pressing. Mainly there is a stacking hole design, instead of the cross-layer blind hole design of the above point 5, the main feature of this design is that there is a need to stack blind holes above the (2-7) buried hole, the difficulty of fabrication is increased, and the buried hole is designed (2 The -7) layer reduces the number of laminations and optimizes the process to achieve cost reduction.
7. Secondary layered HDI designed for cross-layer blind holes (Second-layered HDI 8-layer board, stacked structure is (1+1+4+1+1)) The structure of this type of board is (1+ 1+N+1+1), (N≥2, N even number), this structure is a plate with secondary layers that are difficult to manufacture in the industry. In this design, the inner multi-layer board has buried holes in The layer (3-6) requires three presses to complete. Mainly there is a cross-layer blind hole design, which is difficult to manufacture. It is difficult for HDI PCB manufacturers without certain technical capabilities to make such secondary laminated plates. If this cross-layer blind hole (1-3) layer is optimized, splitting For the blind holes of (1-2) and (2-3), the practice of splitting blind holes is not the split hole splitting method of points 4 and 6 mentioned above, but the blind hole is staggered. The split method will greatly reduce production costs and optimize the production process.
8.Optimization of HDI panels of other laminated structures. Three-layer laminated printed boards or PCB boards with more than three layers or more, according to the design concept provided above, can also be optimized, complete three-layered HDI boards, For the entire complete production process, four presses are required. If the design idea of the above-mentioned laminated plate or secondary laminated plate can be considered, the production process of one press can be reduced, thereby improving the plate. Yield. In many of our customers, there is no shortage of such examples. The laminated structure that is designed to be designed requires four presses. After the optimization of the laminated structure design, the PCB production can be completed only three times. Meet the functions required for the three-layer laminate.