Multilayer PCB, Construction, Working, Types & Applications

Hello, friends, I hope all of you are enjoying your life. In today’s tutorial, I am going to explain Multilayer PCB. The word PCB stands for printed circuit board, it is a circuit board that is used for the construction of different circuits on this board the substrate at which different paths are designed by the copper for the connections of different components used for the circuit. With the creation of this circuit board, our complicated wiring system for the production of circuits has been eliminated. This circuit board is now used in almost every electronic component for calculators to different devices used in medical industries consisting of PCB.

There are many types of PCB according to their use and construction such as single-sided PCB, double-sided PCB, Flexible PCB, Rigid PCB, Rigid-Flex PCB, etc. In today’s post, we will have a look at the multilayer type of printed circuit board. This board consists of more than 2 layers, in this article we will discuss its working, application, advantages, disadvantage, and comparison with other types of PCB. So let’s get started with Multilayer PCB.

Multilayer PCB

• Multilayer PCB consists of a minimum of 3 and larger than three numbers of a layer that has conductive paths.
• All these layers have some insulation material among them and are connected with one another through some adhesive material.

• This structure of a large no of layers provides a large space for the construction of circuits.
• The linking among the layers of the circuit board is done by the plating through-hole method.
• At the central portion of an insulating substance, it has 3 conductive sheets that can also define a conductive track on board.
• Due to the complicated structure of a large no of layers, its design is like the rigid printed circuit board, not possible to make it similar to a flexible PCB.
• Its main benefits are that if you are going to complicated circuits that need a large number of components then you can assemble one hundred layers on a single board.
• But mostly used no of layers is four to eight as it provides a facility to handle complicated projects.
• Some cell phones comprise twelve layers of the printed circuit board as it is compatible with their complex circuit.
• An even no of layers is assembled on a single circuitry board as an odd no of layers creates complications for the construction of circuitry.
• If an odd no of layers is assembled that it not difficult to fold the board after making a connection of components.
• Odd assembly of layers is also expensive.

Manufacturing of Multilayer PCB

Design:

• The first step involved designing the board through the use of software or any tool. To design, the board the engineer must have the expertise to design the board. The design of the board must be optimized to perform the required functions

Layer Creation:

• After the creation of the design layers of boards is created. Every layer is etched on the thin layer of copper that is coated through the use of a photoresist layer. The photoresist is placed in the UV light through the use of the negative image of the design that strengthened the photoresist in places where the design is not included. The non-hardened area is then removed and the required copper pattern is obtained.

Drilling:

• When copper layers are created board is passed through drilling for hole creation and vias that join the layers. The holes are then plated with copper to make conductive paths between layers

Lamination:

• When copper layers are created and holes drilled layers are laminated with each other through the use of heat and combination. The layers are connected through the use of epoxy resin to make multiple layers of board

Plating and etching:

• In this step, external layers of boards are plated through the use of a thin layer of copper to make the conductive surface to perform the soldering. Copper is etched for the removal of additional material and the required pattern is obtained.

Solder mask and silk screen

• When copper layers are passed through the plating and etching board is coated with a layer of solder mask that is used to protect copper traces and vias from environmental conditions like oxidation. The silkscreen is applied on the board that assigns the symbolic representation and other related data.

Board Testing:

• At last, the board passes through testing to make that the required features and functions are existing on the board. Tests like electrical testing, visual inspection and functional testing are performed

Advantages of Multilayer PCB

• These are some advantages of multilayer PCB.

Small Size:

• The important feature of this PCB is that it is available in a smaller size.
• One of the most prominent and lauded benefits of using multilayer PCBs lies in their size.
• Due to their layer structure, multilayer circuit boards are characteristically lesser than other circuit boards with analogous functions.
• This features the most effective use of it for different engineering projects and electronic devices like phones, laptops, and computers.

Lightweight :

• Due to its smaller size, it also has fewer connections for large no of components which decreases its weight.
• Due to less weight, it’s the best option for current electronic devices.

High-Quality:

• The planning and designing used for the creation for this circuit board provide the best quality than the single and dual-sided printed circuit board.

Durability:

• The lifetime of this printed circuit board is longer than other PCBs. These boars do not twist its own until a certain external force is not applied.
• This board also can high temperatures and pressure.

Flexibility:

• Some multilayer printed circuit board has flexible behavior so it is known as flexible multilayer.
• It can be an extremely necessary feature for submissions where mild twisting and bending can exist on a semi-regular base.

More Powerful:

• This type of PCB is a tremendously higher-density structure, that has a large no of layers on a printed circuit board.
• These features make permit circuit boards to be further connective, and their inborn electrical belongings permit them to attain bigger capability and speed in spite of their lesser.

One connection point:

• The structure of this circuit board is like a single unit in spite of a large no of layers. So there is only one input connecting point and not for separately every layer.
• This feature is very helpful for usage in different projects that provides only a single point for input.
• This is also best for such devices that already have a smaller size.
• So it is most useful for the construction of mobile phones.

Multilayer PCB Disadvantages

• Now we describe some drawbacks of this PCB you must be aware of these disadvantages with the benefit of this board.

High Cost:

• The complicated design increases the price of this board more than the single-sided and double-sided boards.
• Its construction is a very difficult and time-consuming process, it also needs special techniques for construction and highly paid labor.
• It is one draws back that makes it costly that during its construction any mistake can lead to aging manufacturing of it and increases the price for labor and material.
• As this is a new invention for industries so some precautions are taken for its use in any project that makes it expensive.
• Due to all these causes, some other less costly option is also available.

Complex Production:

• Due to special manufacturing techniques, and special precautions its construction is more complicated than other PCBs.
• Due to that any minor fault on this board makes it wasteful.

Limited Availability:

• Its main drawback is that the machines required for its manufacturing are very expensive. Almost all PCB producers do not have the funds to buy these machines.
• Due to this, there are very less producers for this board production which make it expensive.

Skilled  Designer Needed:

• As above we discuss that its design is very complicated so some highly skilled producers are required to construct this PCB board.
• If un-skilled men design-construct this board any smaller mistake in this board can cause serious problems in the complete structure.

Creation Time:

• As we discussed above its manufacturing is very complicated and needs special care so it takes a large time for its creation.

Benefits of Multilayer PCBs over Single Layer

• Now we discuss the comparison among the single-layer and multilayer printed circuit boards.

Higher Density:

• The density of a single-sided printed circuit board is less due to the lesser surface area, while the density of a multiple-layer PCB is higher due to a large no of layers.
• Due to this high density, this board provides a large circuit assembly, large capability, and high speed instead of a lesser size.

Small Size:

• Instead of large no layers, the size of the multiple-layer board is smaller which makes it effective for small-size electronics devices and due to large size single-layer PCB is used for large-size devices.

Less Weight:

• Due to the absence of a soldering connection on multiple layers printed circuit boards, its weight is less than the single-layer PCB.

Why Multilayer PCB Mostly Used

• In different industries multilayer PCB is mostly used. Due to enhancement in the different options in the industry and the use of components preferring this board.
• The single and double-layer board has limited in term of board size and operation that has been covered by the multilayer boards.
• But with some advantages, there are some disadvantages use of multilayer boards over single and double layers such as expensive boards and design complications.
• But due to its good operation and working preferred instead of larger cost.
• With the use of new technology and machines, the creation cost of the board is also reduced with great benefits and advantages.

Related Posts

• Aluminum PCB (Printed Circuit Board)
• Multilayer PCB (Printed Circuit Board)
• Rigid PCB (Printed Circuit Board)
• Flex PCB (Printed Circuit Board)
• High Frequency PCB (Printed Circuit Board)
• Single Sided PCB (Printed Circuit Board)
• Rigid-Flex PCB (Printed Circuit Board)
• Double sided PCB (Printed Circuit Board)

That is the detailed tutorial on the multilayer PCB I have mentioned every parameter with detail. If you have any questions about it ask in the comments. Thanks for reading. See you in the next tutorial.