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Multilayer PCB

A multilayer PCB is a board that has a conductor layer (inner layer) inside the board. In addition to the component side and the solder side, and is usually used for a power supply system. As a result, the low impedance due to the wide pattern area and the parallel plate capacitance between the power supply layers form a decoupling effect.

Multilayer PCB 1

What is the difference among various PCB boards layers?

The structure of the printed circuit board depends on the number of mounted components.

If it is sufficient to mount the components on only one side of the board,it will be a single-sided board. And if you want to mount it on both sides, it will be a double-sided board. Single and double sided circuits: things to know.

What is Single Layer PCB?

When we talk about a ‘monolayer’ circuit, we are referring to the simplest model, the single-sided one: it requires that there is a layer of material, with conductive tracks that wind on a single side.The most interesting elements relating to this type of circuits are those relating to the ease of assembly and the reduced costs as regards machining operations.

These are products that are used,for example, in household appliances and in general are perfect for projects linked to large consumption. Even intervening to repair the equipment,in the presence of single-sided circuits, is easier.

What is Double Layer PCB?

On the other hand, we take into consideration the double-sided circuits (those with two layers) they appear to be more flexible and with a decidedly reduced board size:they are probably the most common on the market.

Multilayer PCB 5

Thanks to them – and their wide application flexibility – many and distinct needs can be interpreted in any technological field. The reference is in particular to electronics for motors, but also to the IT and electro medical sectors.

Since it is possible to exploit the two faces,an optimization of spaces is configured and consequently an interesting reduction of costs. With regard to these printed circuits, we should not overlook the wide possibility of customization,linked to the customer’s needs and the relative budget available.

What is Multilayer PCB

It may happen that a single or even a double layer is not sufficient to satisfy certain application needs.The solution, in this case, is represented by the use of multilayer PCB.

The latter,of course, see the presence of a variable and higher number of layers of material:from 4 layer,6 layer,8layer and more layers.In these particular products the tracks cross the layers, which allows to optimize the available space?This results in an interesting and greater compactness of the circuit. This latter aspect is particularly interesting in the case of devices with small dimensions.

How to Design Multilayer PCB?

By patterning the board in multiple layers,the pattern is placed in the inner layer,increasing the area where components can be mounted.This is the advantage of the multilayer PCB board.

The through holes used in the two-layer board will be connected to the inner layer if left untouched.Therefore, in the case of through holes such as signal lines that do not connect to the inner layer, it is necessary to provide a pattern that do not connect to the inner layer.

Also, when it is desired to connect to the inner layer such as the power supply system,if such a pattern is not provided, the through hole is directly connected to the conductor of the inner layer. So the connection is made.

However,in such a connection,when soldering by inserting the component into the through hole there,it is difficult to solder because heat does not easily transfer.Therefore, so-called thermal pads that are connected in a cross pattern.

How Are Multilayer PCBs Manufacturing?

Multilayer PCB – A PCB consisting of multiple layers of dielectric with conductive patterns between the layers and on the outside.

Manufacturing of multilayer printed circuit boards consists of creating separate layers according to the technologies of single and double-sided boards and their subsequent joining by pressing.The layers are joined using a specialized sheet material based on resin – prepreg,which has adhesive properties.

Switching of conductors of different layers is carried out using plated holes, which can be through, hidden (when switching two or more layers inside the board) or blind (when switching one outer layer with one or more inner layers).

The number of layers in multilayer boards is limited by the:

  • Overall board thickness
  • The ability to align layers
  • The reliability of the plated holes

Multilayer PCB with about 20 layers are widespread.

What are the Major Applications of Multilayer PCB Boards?

Multilayer PCB (PCBs) are used to design complex devices that require high component density.The number of layers depends entirely on the complexity of the task of the PCB designer.

Computers,File servers,Data storage,Signal transmission,Cell phone transmission,Cell phone repeaters,GPS technology,Industrial controls,Satellite systems,Hand held devices,Test equipment,X-ray equipment,Heart monitors,Cat scan technology,Atomic accelerators,Central fire alarm systems,Fiber optic receptors,Power supply,Medical devices,Nuclear detection systems,Space probe equipment,Weather analysis,etc.

Multilayer PCBs can contain up to 40 layers.It provides a high specific density of printed conductors and pads.Other advantages of printed circuit boards of this type include the reduction in the length of the conductors.

A multilayer printed circuit board consists of a series of superimposed layers.In which are formed connecting conductors for transmitting signals,conductive surfaces for supplying voltages, grounding circuits,and pads or tabs for connecting leads.

Often, a heat-conducting material is included in the structure of a multilayer board for cooling.A connector is installed on one of the edges of the board.

It significantly increases the speed (for example, the speed of data processing in a computer).Also multilayer printed circuit boards allow shielding of AC circuits.

1) Dielectric.
2) Protective layer (mask).
3) Contact hole.
4) Conductive track.

PCBMay is an Experienced Multilayer PCB Manufacturer

PCBMay has been producing Multilayer PCBs for over 10 years. Over the years, we have seen all types of multilayer constructions from various industries, answered all types of multilayer questions, and solved all types of problems with multilayer PCBs.

ItemCapability
Layer Count1-40layers
Base MaterialKB、Shengyi、ShengyiSF305、FR408、FR408HR、IS410、FR406、GETEK、370HR、IT180A、Rogers4350B、Rogers4000、PTFE Laminates(Rogers series、Taconic series、Arlon series、Nelco series)、Rogers/Taconic/Arlon/Nelco laminate with FR-4 material(including partial Ro4350B hybrid laminating with FR-4)
Board TypeBackplane、HDI、High multi-layer 、blind&buried PCB、Embedded Capacitance、Embedded resistance board 、Heavy copper power PCB、Backdrill.
Board Thickness0.2-5.0mm
Copper ThicknessMin. 1/2 OZ, Max. 10 OZ
PTH Wall25um(1mil)
Maximum Board Size1100*500mm(43”*19”)
Min laser drilling size4mil
Min. Spacing/Tracing2.7mil/2.7mil
Solder MaskGreen, Black, Blue, Red, White, Yellow,Purple matte/glossy
Surface TreatmentFlash gold(electroplated gold)、ENIG、Hard gold、Flash gold、HASL Lead free、OSP、ENEPIG、Soft gold、Immersion silver、Immersion Tin、ENIG+OSP,ENIG+Gold finger,Flash gold(electroplated gold)+Gold finger,Immersion silver+Gold finger,Immersion Tin+Gold finge
Min. Annular Ring3mil
Aspect ratio10:1(HASL Lead free、HASL Lead、ENIG、Immersion Tin、Immersion silver、ENEPIG);8:1(OSP)
Impedance control±5ohm(<50ohm), ±10%(≥50ohm)
Other TechniquesBlind/Buried Via
Gold Fingers
Press Fit
Via in Pad
Electrical Test

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