4 Layer PCB Stack-Up

In this guide, you will find all information you need on 4 layer PCB stackup.

So, before you start your next PCB layer stackup project, read this guide.

Let’s dive right in.

What is a 4 Layer PCB Stackup?

4 Layer PCB stackups are special types of multilayer boards with two major internal layers and blind vias.

You will use the blind vias for mounting of different types of components that perform different functions.

Among the two internal layers in the 4 Layer PCB stack up, you will have the ground plane and the signal layer.

4 layer pcb stack up

How Much Does a 4 Layer PCB Stackup Cost?

We are of the belief that pricing of the 4-layer printed circuit board stackup should be as fair to you as possible.

Here, you will not pay hidden fee but the fee we need to ensure you get high-quality 4-layer PCB stackup.

Here are some of the factors that will affect the amount of money you will pay for the 4-layer PCB stackup.

Quality of the Stackup

Here, the higher the quality of the 4-layer printed circuit board stackup, the higher the amount you will pay.

Usually, high quality materials cost a lot more than the low-quality materials thus attracting higher sale prices.

Quantity of Stackups

You should also note that the higher the quantity of 4-layer PCB stackups you purchase, the higher the cost.

There is a possibility that you might benefit from discounts if you purchase the 4-layer PCB stackups in bulk.

Size or Dimensions of Stackups

You must also note that the bigger the size of the 4-layer PCB stackup, the higher the amount of money to pay.

In other words, you should prepare to pay higher prices for the bigger sizes of 4-layer printed circuit board stackups.

Generally, you will pay between 0.10 to 5 US dollars for every piece of the 4-layer printed circuit board stackup.

What are the Tips for Designing a 4 Layer PCB Stackup?

You may think that manufacturing the 4-layer printed circuit board stackup is such a big deal.

Well, it is a big deal that you can simply navigate through if you have a very good plan or design.

Implying that, you should have a proper design of the 4-layer PCB stackup before you begin the manufacturing process.

Here are a few tips that you can follow to properly come up with the right 4-layer PCB stackup design.

Determine Number of Layers

First, you have to know the number of layers that you will want to have on the printed circuit board layer stackup.

In this case, you will be designing the 4-layer PCB stackup thus limiting the number of layers to 4 layers.

There are, however, particular techniques that you can use to determine the right number of layers for your stackup.

Determine Arrangement of Layers

With the number of layers at hand, you can proceed with the determination of the placement or arrangement of layers.

To determine the best arrangement, here are some of the rules that you should follow.

i. Route the minimum thickness microstrips on the high-speed signals

ii. Place the internal power layers and the signal layers closer for tight coupling.

iii. Maintain minimal spacing between the ground layers and the power layers.

iv. You must not place signal layers in adjacent positions to one another

v. As the stackup layers move inwards, you must make sure that they are symmetric from top to bottom.

Determine the Type of Materials

One of the important aspects that you need to look at is the thickness of the signal layers.

Determining the thickness of the core as well as the prepreg will ensure that you have control over signal layer thickness.

You should also note that there are standard thicknesses in conjunction with other properties depending on the material types.

Determining the Vias and Routes

Here, you will determine the routing of the traces that you will have on the 4-layer printed circuit board stackup.

You will determine copper weights, location of vias, types of routes and vias, in addition to other specifications.

How Do You Design a 4 Layer PCB Stackup?

With the tips at hand, you can now proceed to the designing process of the 4-layer PCB stackup.

You work will be a lot easier with the help of a PCB layer stackup design software.

Here is a step-by-step process that you can follow to successfully design a 4-layer PCB stackup.

Step One: Creating the Schematic

You can create the design from scratch or use a template but you should always begin the process by creating a schematic.

It is the foundation or the blueprint that you will use in coming up with the whole design of 4-layer PCB stackup.

In the schematic, you must make sure that you have the following details.

i. Components that you will use in the layer stackup design

ii. Connection that exists between the different components

iii. Relationship that exists between the different groups of components on varying schematics

After that, you will proceed to create a blank PCB layout to begin the whole designing process.

This blank document will generate the file where you will store the design you are working on.

It is also the point where you will include all the dimensions that you want on your 4-layer PCB stackup.

Here, you will do a proper design verification and then generate all the documents you need for the project.

Step Two: Capturing the Schematic

You will make the designing process of the layer stackup easier by linking various aspects together.

Here, you will link the aspect of the layer stackup, PCB components, and bill of materials in the right place.

In case of any changes, you can make the necessary changes and then proceed to update the whole file.

With this in place, you will have access to all the relevant information that you need for the designing process.

Step Three: Designing the Layer PCB Stackup

It is very important to determine the right PCB layer stackup or layout before you mount the components.

Here, you will determine the number of layers as 4 on FR-4 even though you can also change the materials.

Implying that, there is a very wide range of laminate materials that you can use to make the 4-layer PCB stackup.

You can also explore the impedance profiler to help control the impedance in high-speed or high-frequency designs.

As you perform all this, you must stay within the design rules to ensure that every aspect is under control.

As soon as you complete this process, you can proceed with component placement, drill hole insertion and route tracing.

These steps come in handy when you are designing the entire printed circuit board not forgetting addition of identifiers and labels.

Finally, you will generate the design files in formats that the manufacturer will understand very easily.

What are the Main Components of the 4 Layer PCB Stackup Materials?

Obviously, whenever you are creating anything, you must have the right materials.

In this case, we are going to have a look at the materials you will need to create 4-layer PCB stackups.

Here are the main materials that you must have to manufacture the 4-layer PCB stackup.

Dielectric Materials

As the printed circuit board runs rapid signals, the dielectric material will offer two major functions.

You will depend on the dielectric materials to help in the isolation of signals on the adjacent printed circuit board layers.

It is also important to note that PCB stability will depend highly on steady impedance of the dielectric materials.

In other words, you will use the dielectric materials to monitor impedance over extensive frequency ranges.

dielectrics materials

Copper Materials

You will also use copper as a PCB layer stackup material due to the conductive nature of copper.

It has excellent conductor properties capable of conducting electricity and heat within the printed circuit board.

You should be very careful and look at the dimension controls of copper to achieve proper amount of current flow.

You can also use it in the description of current loss that may occur during the application function of the PCB.

In addition to that, you must also control the quality of copper in order to control the impedance of ground planes.

Trace Dimensions

You will use the trace dimensions to determine the right dimensions and the mechanical layers.

Apart from that, you can use the trace dimensions to provide the foundational measurements of the layer stackup.

You will also use it in the location as well as mounting of the components or electronic devices on the layer stackups.

How Does a Single Layer PCB Compare to a 4 Layer PCB Stackup?

Just from the name, you can note that there is a difference in the number of layers on the stackups.

Single layer PCB, is however, not a stackup but consists of only one layer of conductive materials.

You will use the single layer PCB for low densities and very simple design applications.

On the other hand, we have the 4-layer PCB stackup which as 4 layers ideal for smaller boards.

single layer pcb

Apart from that, you can use them for breakouts as well as smaller boards even though complexity increases.

In addition to that, they also come in handy for base boards and micro-controller boards.

In terms of cost, you will spend more money in the processing of the 4-layer PCB stackup than single layer PCBs.

How Do You Manufacture the 4 Layer PCB Stackup?

You will proceed with the manufacturing process of the 4-layer PCB stackup as soon as you approve the design.

Implying that, you will have to look at the design of the 4-layer printed circuit board stackup and test functionality.

If it passes the functionality test, you will draw a plan that will guide you on how to manufacture the 4-layer PCB stackup.

With the plan at hand, you will proceed with the manufacturing process by going through the following steps.

Step One: Preparation of Materials

First, you will begin the manufacturing process by preparing the materials that you need for the 4-layer PCB stackup.

Some of the materials that you will need are conductive materials such as copper and substrate layers such as glass-epoxy.

In preparation of the materials, you will also measure them into the right sizes and cut them accordingly.

Apart from the materials, you must also make sure that the machines are ready for the whole manufacturing process.

You must also consider the load points on the 4-layer PCB stack up very carefully to ensure proper functionality.

Step Two: Printing the Layout

Here, you will use a special type of printer which you can identify as a plotter printer to make the film of the stack up.

You will end up with a photo negative of the 4-layer printed circuit board stackup that will guide the manufacturer.

Inside the photo negative, you will have the black ink representing the copper traces and the clear ink representing non-conductive areas.

On the outer layer, black ink will represent non-conductive layers while the clear ink will represent conductive areas.

As soon as the print out is complete, you will punch registration holes inside as a guide for aligning the films.

Step Three: Printing and Etching of the Copper and Non-conductive Substrates

You will begin by printing the copper for the interior layers of the layer stack up through the inner layer imaging process.

After that, you will proceed to the inner layer etching which is often a chemical process that removes unwanted parts.

As soon as that is complete, you will proceed with resist stripping that will remove the remaining resist covering inner layers.

You will clean any resist that remains thus ensuring that the copper does not have parts that hamper its conductivity.

After inspecting, you will perform poste etch punch that will align all the layers using the registration hole.

On the same breath, you will proceed with the automatic optical inspection (AOI) of the inner layers to trace incomplete patterns.

You will apply oxide on the inner layers that will ensure proper bonding of insulating epoxy and copper foils.

Finally, you will lay up all the layers of the 4-layer printed circuit board with the help of a machine.

It will align, heat, and bond all the layers of the 4-layer PCB stack up before laminating and completing the whole process.

You can complete the entire process by performing automated optical inspection (AOI) on the 4-layer PCB stack up.

How Does a 2 Layer PCB Stack up Compare to a 4 Layer PC Stack up?

Signal interference and integrity play a huge role in differentiating 2-layer and 4-layer PCB stackups.

Just from the name, you will realize that the 4-layer PCB stackup has more layers than the 2-layer PCB stackup.

Implying that, the 4-layer PCB stackup has more layers that will help in managing signal interference and signal integrity.

In addition to the number of layers, you will also note that the 4-layer PCB stackup has larger surface areas.

In other words, it has more space or surface area that you can use to help in placement of the components.

Despite that superiority, additional layers on the 4-layer PCB stackup will cost you more than the 2-layer PCB stackup.

2 layer PCB

How Many Types of Layers Do You Include in a 4 Layer PCB Stack up?

Basically, the name of the 4-layer PCB stack up denotes that the stack up has 4 layers.

Well, that may be true on the surface but the layers denote a very different arrangement.

Here are the main types of layers that you will find on the 4-layer PCB stack up.

Top layer

This is the layer that you will find on the upper most part of the 4-layer PCB stack up.

It is the layer that will carry the surface finishes and the solder masks plus the components of the PCB.

Layer 2

This is the second layer that follows the top layer which you can consider to be an inner layer of the PCB.

In layer 2, you will have the prepreg 1 and prepreg 2 that perform major functions on the 4-layer PCB stack up.

Layer 3

Just before you reach layer 3, you will have the core 2-3 that separates or connects layer 2 from layer 3.

After layer 3, you will have the prepreg 3-4 which will connect or separate layer 3 from the bottom layer.

Bottom Layer

Finally, you will have the bottom layer of the 4-layer PCB stack up that will carry the weight of all the layers.

What is the Turnaround Time for Manufacturing 4 Layer PCB Stack up?

You will wait for between 7 to 9 days to complete the manufacturing of the 4-layer PCB stack up.

In the earliest convenience, you will receive the 4-layer PCB stack up in 7 days after the complete order.

You may have to wait for a maximum of 9 days if there are delays in the manufacturing of the 4-layer PCB stack up.

Which Materials Do You Use to Manufacture the 4 Layer PCB Stack up?

There are two main materials that you will use in the manufacturing process of the 4-layer PC stack up.

Here are the main materials that you will use to manufacture the 4-layer printed circuit board stack up.

Conductor Materials

You will need conductor materials that will help in conducting electricity as well as heat through the PCB.

The best conductor material that you can use is copper which provides excellent heat and electric current conductivity.

Substrate Materials

In addition to the conductor materials, you will have the substrate materials which act as the insulation materials.

You will use the insulation materials to block any form of electric current or heat flow through the layer stackups.

What are the Main Properties to Consider When Designing the 4 Layer PCB Stack up?

There are very important properties or attributes of the 4-layer PCB stack up that you ought to look at.

In reality, these are the properties that will describe the types of materials you need to manufacture 4-layer PCB stack up.

Here are the main properties to consider when choosing the 4-layer PCB stack up materials.

Coefficient of Thermal Expansion (CTE)

Here, you will look at how much the 4-layer PCB stack up expands under different temperature conditions.

You will measure the coefficient of thermal expansion (CTE) and express the final value in parts per meter over degrees centigrade.

Glass Transition Temperature (Tg)

You will also have a look at the behavior of the materials for making the 4-layer PCB stack up under heat exposure.

It is important to know the temperature where the prepreg resin will transit from rigid to elastic materials.

Dielectric Constant

You should also look at the ability of the material to conduct electric current as well as store electric charge.

Here, you will be looking at the average capacity of electric charge that you will need to perform signal transmission.

Dissipation Factors and Loss Tangent

You should also note that there is partial absorption of electric charges and signals as it travels through the materials.

It is, therefore, very important to look at the resistance that the materials will have against the loss of electric current.

How Do You Estimate the Number of Signal Layers on the 4 Layer PCB Stack up?

It is important to have the knowledge on the number of layers that will perform specific functions.

You can ensure that you have all the right estimates through two most important ways.

Here are the methods you will use in determining the number of signal layers.

• Assume Components with Highest Pin Numbers
• Using the Rent’s Rule

What are Some of the Reference Plane Considerations on the 4 Layer PCB Stack up?

As soon as you have the number of layers in place, you should work on the right number of planes you need.

Here, you will consider the following factors to get the right plane considerations on the 4-layer PCB stack up.

• Functions of the power and ground planes
• Structural resonance pf the power and ground planes
• Cavity resonance between the planes

How Do You Control Impedance on the 4 Layer PCB Stack up?

Control impedance PCB

With the designing software, you can control impedance simply by adjusting the size of the 4-layer PCB stack up.

In most case, you will improve or control impedance on the stack up by increasing number of layers.

Since we cannot increase the number of layers further, we will control impedance by controlling sizes.

You will improve the overall size of the 4-layer stack up and also improve the thickness of the materials.

What is the Difference Between 4 Layer PWB Stack up and 4 Layer PCB Stack up?

PWBs are the printed wiring boards while the PCBs are the printed circuit boards.

You will use a printed wiring board to create electrical networks over substrates and etched conductive plates.

On the other hand, printed circuit boards will create physical support for the electronic components through electrical connections.

You can have both PCB and PWB with a population of components that determine their functional alignments.

Which Surface Finishes Can You Apply on the 4 Layer PCB Stack up?

There are quite a number of surface finishes that you can use to improve connectivity and image of the stack up.

Here is a list of the main PCB surface finishes for the 4-layer printed circuit board stack up.

• Hot Air Solder Level (HASL) Surface Finish
• Lead-Free Hot Air Solder Level Surface Finish
• Organic Solder ability Preservative (OSP) Surface Finish
• Immersion Silver (Au) Surface Finish
• Immersion Tin (Sn) Surface Finish
• Electro less Nickel Immersion Gold (ENIG) Surface Finish
• Electro less Nickel Electro less Palladium Immersion Gold (ENEPIG) Surface Finish

Which Other Conductive Materials Can You Use other than Copper?

Apart from copper, you can use other metals that have great conductivity as well as low resistance.

Alternatively, you can use silver, or gold material to assist in the conductivity of electric current and signals.

These materials have great electric conductivity and very low resistance levels even though they are expensive.

What Influences the Current Carrying Capacity of the 4 Layer PCB Stack up?

Well, the current carrying capacity of the 4-layer PCB stack up will have a great impact on signal transmission.

Implying that, the better the current carrying capacity, the higher the probability of signal transmission.

In other words, you can increase the current carrying capacity by increasing area of application and copper thickness.

What are Some of the Applications of the 4 Layer PCB Stack up?

You can use the 4-layer PCB stack up in quite a number of applications.

It is the simplest form of a reliable printed circuit board that can perform various functions.

Here are some of the applications of the 4-layer printed circuit board stack up.

You will find them on electronic circuits in different industries such as:

• Communication Industry
• Medical Industry
• Aviation Industry
• Automobile Industry
• Space Exploration Machines

At Venture Electronics, we help you get the best 4 layer PCB stackup depending on your unique application requirements.

Contact us today for any questions or inquires about 4 layer PCB stack up.