Multilayer PCB Design Tutorial
There's nothing better in the world than a six-layer chocolate cake. I do love the single-layer cake, but it can't compare to its larger, more decadent six-layer cousin. However, a six-layer cake requires more time to prepare, more baking skills, and it will be more expensive than a simple cake. It also takes a little extra time in the gym to make up for the extra calories, but in the end it's really worth it.
If you've only laid out a simple one- or two-layer board, you'll find that laying out a multi-layer PCB has some similarities to a six-layer cake. Like cake, it takes more time, more skill and more cost, but it would also be a very enjoyable design challenge without the burden of going to the gym the next day. However, there will be some new design methodologies to learn, which we will introduce to you in this multi-layer PCB design tutorial.
A multilayer PCB is a printed circuit board with more than 2 layers. Double-sided PCBs have two conductive layers on the top and bottom of the PCB substrate. Multilayer PCBs must have at least 3 layers of conductive material or copper. All layers are interconnected through copper plated vias. The number of layers can be 4, 6, 8...up to 40 layers.
Multilayer PCB designs are complex. The top and bottom layers look the same as a double-sided PCB, but with stacked layers on both sides of the core. All layers are compressed to form a single multilayer PCB where all layers are interconnected through copper plated vias.

First Steps of the Multilayer PCB Design Tutorial; Setup and Preparation
In some cases, older traditional PCB footprints may not be sufficient for multi-layer designs and you need to know if there are any additional requirements. Depending on the CAD system used, you may have to add layers or properties to the footprint for use by multiple layers. Here, having access to more advanced PCB design systems with links to online library services can be a real benefit. It makes it easier to use the latest and most accurate PCB footprint source data.
The main difference between two-layer and multi-layer board setups is planning the layer stackup. Here are some points you need to consider when planning your ply stackup:
Performance: The speed at which the circuit operates and the environment in which the final board will operate can have an impact on the materials the board is made of. Depending on your needs, there are more advanced materials than FR-4 that may be more suitable for your application, but these may affect parameters such as impedance calculations. Here, the help of your PCB manufacturer will be an invaluable source of information.
Cost: The materials of manufacture as well as the number and configuration of layers will directly affect the overall cost of building the board. Here again you need to work with the manufacturer to consider all options.
Density: The routing density of the board is another factor that determines the configuration of the board layer stackup. It's a real pain when you have to go back and add layers to your board design after you've already started layout. Not only will you need to reconfigure the CAD database, but you may need to make extensive changes to the layout. On the other hand, if you start with too many layers, then you should pay more for the board.