What Is 4 Layers PCB Board: (Step By Step Guide 2022)?

How 4layers PCBs are Best for Complex Devices or Gadgets?

The use of PCBs have become an essential need in our daily lives.

Appliances of daily uses even from kitchen gadgets to smartphones and industrial equipment to microwaves all depend upon the PCBs.

Moreover, 4 layers PCB boards have the ability to support a very high level of PCB complexity.

In fact, these PCBs are playing a crucial role in making the electronics industry successful.

Electronic designers are using them in medical devices, consumer electronics, industrial equipment, automotive components, and so on.

Furthermore, it is difficult to determine their uses in electronic appliances as they are part and parcel of them.

So, here we are to describe to you full information about PCBs and 4 layers PCBs.

What is a PCB?

Today PCB is performing a very special role in all industries. Basically, a PCB is a very thin board and designers make it with:

  • Epoxy
  • Fiberglass and many other laminate materials.



In the modern world, PCBs are performing as the important functional centers of nearly all electronic appliances.

Actually, they are small chips present in all electronic appliances and devices.

Hence, these small chips are of very different kinds and contain several layers.

The number of layers totally depends on the device’s needs and requirements.

Electronic engineers are getting the following benefits from PCBs. Such as:

  • Reduce the use of wires but has the ability to hold a mass number of components
  • It is very easy to check and repair the faults in PCBs
  • All the components of PCBs are fixed in proper places
  • PCBs are greatly reliable
  • They can save your precious time and money
  • Using copper reduces the chances of short circuits
  • PCBs are also helpful to reduce or almost finish the electronic noise
  • It is more convenient and time-saving to use the method of PCB boards

How Many Layers Are There In A PCB?

When we talk about PCBs, there are several kinds of PCBs with different no. of layers. A PCB may have,

So, designers select these layers according to their needs. The more complex your device, the more layers it will use.

Inside the PCBs actually, there is more than one conductor pattern.

Because electronic designers use multiple patterns within the circuit boards. It is to add diversity for better performance in tough conditions.

So, they get multi-layers of PCBs by laminating many double-sided boards together, and between these boards, they use insulating layers.

Mostly the number of layers of any PCB is even such as 2, 4, 8, ……, 100, and so on.

While these even layers also include 2 outer layers.

It happens rarely when the number of layers exceeds 100 because PCB manufacturers mostly design PCBs with 100 layers.

PCBs According to the Material from Which They are Made:


PCB Materials

PCB Materials

  • FR-1 / FR-2: These PCB materials are prepared using phenol and paper. These are considered best for single pcb.
  • FR-3: Cellulosic paper and epoxy
  • FR-4: glass fiber and epoxy
  • FR-5: a glass fiber reinforcement in a high-temperature epoxy resin binder
  • FR-6: Nonwoven glass wool and polyester
  • G-10: It is a composite material consisting of glass fiber fabric and epoxy resin.
  • CEM-2: Cellulosic paper and epoxy
  • CEM-3: Series Copper Clad Laminate Products of this type are produced in three substrate colors: white, black, and natural color.
  • RO3000: has excellent electrical properties and high thermal stability at high frequencies.

What Is a 4 Layers PCB?

4 layers PCB boards are actually getting extreme popularity in electronics mostly in complex devices.

In fact, PCB boards with 4layers are an ideal choice for high signal intensity. PCBs having 4layers also have the capability to assist very high levels of complex gadgets.

Furthermore, these PCBs have been created with the help of 4 layers of copper laminated together.

In the process of creating the 4 layers of PCBs, designers start to make use of a single core.

Moreover, this core actually consists of similar materials which they use in creating 2layers PCB.

Additionally, after etching the inner core they add,

  • A prepreg layer
  • Soft fiberglass.

This fiberglass actually has the ability to remain all the layers together.

Moreover, after the board goes through a hot press, it becomes very hard fiberglass. Hence, after this curing process, 4layers PCB boards are very tough, strong, and durable.

Furthermore, if an electronic engineer is going to create a PCB with 4layers, it will make use of,

  • Prepreg
  • One core
  • Copper foil

for the bottom and top layers.

What is the Stackup of 4layers PCB Boards?

The stackup of PCB boards with 4layers is fully intricate and elaborate.

It consists of, two inner layers. And inner layers 1 and 2 actually have sandwiched between the bottom and top layers.

The 4-layer PCB stack up from top to bottom looks like:
  • Top layer for a signal with a width of 0.0014 inches
  • A prepreg layer with a thickness of 0.0091 inches
  • The dielectric constant of 4.2 inches

Moreover, designers make use of copper material for the top layer of PCB.

There is an inner layer 1 after prepreg layer, with 0.0014 inches, designers often referred to it as the plane.

Additionally, there is another inner layer 2, before it, there is a core sublayer which is the part of inner layer 1.

The width of this core sublayer is 0.037 inches. Hence, inner layer 2 is basically another plane layer. And it has made of 1 oz. copper with a thickness of 0.0014 inches.

There is actually another prepreg sublayer that consists of 2 sheets with a thickness of 0.0091 inches.

These 2 sheets actually form part of inner layer 2.

Furthermore, the bottom layer is also the final layer of the 4layer PCB board.

It is also its signal layer and its thickness is 0.0014 inches.

Basically, Interconnects have been soldered and placed on the bottom and top layers.

As we have already described that in a PCB with 4layer there is an extra-wide surface area for traces.

Electronic designers involve a prepreg layer that connects two or more two double-sided boards by applying pressure and heat.

Hence, 4layer PCB is always a better choice as its design actually consists,

  • VCC plane and ground layers
  • Additional two layers of signals.

You can also understand its stack up with the help of the following figure:

4layer stackup

4layer stackup

Is 4layer PCB Board Expensive?

When we talk about the cost, 4layer PCB board is highly expensive.

Because it is highly sensitive and its design is also very complex.

Moreover, there is another factor which is involved in its price.

Such as, it can provide supreme quality of signals because it can reduce propagation and distortion levels.

Hence, 4layer PCBs also have the ability to reduce interference levels and provide higher levels of signal integrity.

Although, they are expensive but becoming the most investing choice for most electronic manufacturers.

What Are 3 Factors To Choose 4layer PCB Board?

In fact, here are 3 factors for which electronic designers prefer to choose 4layers PCBs.

These are:

  1. 4layer PCB board is the best option to select as it has more functionality in a very small space.
  2. 4layer PCBs are also best for complex designs or devices
  3. They are extra durable and long-lasting. So, for durable devices, they are the correct choices.

What are the Advantages of Using 4layers PCB Boards?

Although 4layers PCBs have several advantages but most important benefit is, it actually has two additional routing layers for signals.

Furthermore, these layers allow reducing the PCB size and are helpful for complex appliances or devices. For example, BGA actually needs 200 connections.

4layer PCB boards are very beneficial for makers who actually have a deep interest in order to sell their designs.

Basically, the electronic devices which designers create to sell commercially need a certificate by CE or FCC.

Moreover, they are strict about not emitting radio energy through a specified value.

The most important thing about these PCBs is, they have the ability to make signal routing better in comparison to 2layers PCBs.

In fact, it removes all ground and power connections from signal routing layers. So, it can free up a lot of space for signals.

4 layers PCB

4 layers PCB

Here are Some Sensational Advantages of 4layers (Multilayer) PCBs:

Lightweight in construction:

In fact, these PCBs are small in size and hence are lightweight.

So, they are most advantageous for modern and smart electronic devices and gadgets.

Higher durability:

4layers PCB boards are extremely durable, strong, and have the capability to endure the pressure and heat which has applied to them.

Excellence in Quality:

These PCBs are perfect in quality and functionality in comparison to 1layer or 2layer PCBs.

Moreover, they are highly reliable for complex designs because of the investment of extra energy and time.

Highly powerful:

These PCBs actually have greater capacity and very high density.

Moreover, 4layers PCBs have better speed in comparison to other versions of PCBs.

Single Connection Point:

4layers PCBs are very advantageous for those devices and appliances where the restriction is present in weight and size.

They have become compact because they have a single connection point.

Small in Size:

The best thing about 4layers PCB boards is that they are very small in size. Hence, these are a perfect choice for,

  • Smartphones
  • Tablets
  • Laptop
  • Wearable and many more.

Multilayer PCBs have one or more conductor buses to increase the wiring space.

Multilayer PCB circuit boards; For example, 4 layer PCB and 6 layer PCB circuit boards are formed by pressing more than two copper path layers between the main layers.

4-layer PCB production is achieved by increasing the cable areas on the circuit board by bonding (lamination) with insulation layers between the double-sided circuit board.

Why Multilayer Boards have Become Indispensable?

Due to the increase in cable density on integrated circuits in large R&D projects, the use of multilayer PCBs becomes necessary.

In today’s electronic requirements, often in multi-layer PCB solutions, there are layers of different circuit paths between 4 layers, 6 layers, 8 layers, and 10 layers on the circuit boards.

However, according to the size of our electronic projects, PCB circuit boards with approximately 100 layers can be made.

Nowadays, especially consumer electronics-related products are getting smaller, and the use of multi-layer PCB electronic circuit boards is increasing more and more.

As the number of layers and layers increase on multi-layer PCBs, costs increase in multi-layer PCB circuit boards.

The disadvantages of multi-layer circuit boards, apart from their high cost, are long production times and time-consuming electrical circuit board testing processes.


4layers PCBs are extremely beneficial for highly functioning electronic devices and smartphones.

In fact, they are the first choice for all electronic manufacturers.

Furthermore, these PCBs also have some drawbacks. Such as, 4layers PCBs are expensive and also need more time to design them.

Although, these are major disadvantages they are negligible and unimportant.

Because today, 4layers PCB boards are rigorously and widely used for all modern appliances.

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