Multilayer PCBs

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What is the multilayer PCB

Why choose PCBONLINE multilayer PCB

PCBONLINE is a multilayer PCB manufacturer with 15 years of experience in China. With rich professional manufacturing experience in multilayer pcb technology and advantages in multilayer PCB price.

1.In the production of multilayer PCB, it is difficult for many multilayer PCB manufacturers to control the warping degree of boards, especially PCB with more than 10 layers. However, PCBONLINE has very good control in this aspect. Our project can be controlled by the following methods: A.The arrangement of the prepregs between each layer shall be symmetrical. For example, in six layers, the thickness and number of prepregs from the first to the second and from the fifth to the sixth layers shall be the same, otherwise, the lamination will be prone to warping.
B.Multilayer core plates and prepregs shall be made from the same supplier.
C.The line area of the outer layer side A and side B should be as close as possible. If side A is a large copper surface, and side B only have few lines, the printed circuit board is easy to warp after etching. If the line area difference between the two sides is very large, separate grids can be added on the sparse side to balance it out.

2.After the production of all the inner and outer layers, all the AOI tests will be carried out. For the impedance PCB, all the line widths will be within the tolerance of +/-10%. For the open-circuit boards, they will not be repaired and will be scrapped directly.

3.Multilayer PCB connects the inner and outer layers together through copper in the hole wall, so copper through holes is crucial for multilayer boards. In the production process, it is easy to have no copper in the hole. During the production of PCBONLINE, strict control is carried out by the following methods. A.Because the multilayer PCB is through many single and double boards stacked together and pressed together. During drilling, PCBONLINE reduces the cutting speed and rotation speed, and all the drill bits are completely new, which can reduce burr and roughness of the hole.
B.Before electroplating, PCBONLINE must have the process of removing rubber residue, to ensure that all burrs in the holes are removed clean, to prevent the electroplating without electricity to copper, resulting in no copper in the holes.

4.Surface finished is also critical to the quality of the multilayer PCB A.If the surface finished of the multilayer PCB is HASL lead-free, even if the customer does not require the use of high TG material, PCBONLINE use high TG board by default to prevent the bursting of the board when spraying tin.
B.The gold covering the surface of the pads in the ENIG surface finished process is flat and very easy to weld parts. It will not have poor soldering conditions resulting in pseudo soldering. Because there are many reasons that can cause pseudo soldering, in addition, engineers to deal with the problem of pseudo soldering is very troublesome, so multilayer printed circuit board ENIG process, generally can be very good to avoid pseudo soldering. PCBONLINE all suggest customers to adopt gold sinking process. Meanwhile, PCBONLINE has its own production line of immersion gold process, which can reduce the cost of multilayer PCB boards and reduce the procurement cost for customers.

5.Leading process capability in the industry.The following table shows the process capacity of PCBONLINE

Item Value
Layer count 8-24
HDI Stack up 1+N+1,2+N+2,3+N+3(with copper filling)
Final board thickness 0.15-3.2mm
Aspect Ratio Laser via
Copper thickness 1/3~6oz
Single Ended
+/- 10%
+/- 10%
Line/Space Inner Layer
External Layer
Min Drill Bit size 8mil
Hole size
Hole Position Tolerance +/-2mil
Soldermask Line to PAD
Warpage 0.5%
Surface Finish HASL(LF HASL)
Immersion Tin
Immersion Silver
Hard Gold Plating
Peelable Mask
Carbon ink
SMD 40-2000u", GND 30-800u"
Au 1-5u", Ni 80-200u"
Au 1-50u", Ni 80-200u"

The knowledge involved in multilayer pcb technology is enormous. If you can contact us directly on design, for example:

1.The impact of the thickness of the multilayer on the impedance. Our engineers carry out the multilayer PCB thickness through polar SI9000 software , and we can help you check whether the impedance line is reasonable or not.

2.multilayer pcb stack up structure, how to choose a more reasonable structure, so that the procurement cost is lower.You can also change the pressing structure directly in our ordering system

If you have any questions about multilayer PCB layout, please feel free to contact us.

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