Electronic devices are getting more and more complex. This means they need powerful and reliable printed circuit boards. However, instead of using several PCBs in a single device, the best option is to stack them up in several layers.
Hence, PCB stackup is one of the vital steps in printed circuit design. But what are the layers of stackup for common PCBs and what are the common types of PCB layer stackup?
What is PCB layer stackup?
PCB layer stackup, also known as the layer build-up, is the arrangement of insulating layers and copper layers that make up a printed circuit board. Copper layers and insulating layers are stacked together through prepreg.
What is the purpose of PCB layer stackups?
*Layer stackups help to multiply the functionality and speed of the electronic device. This means it makes a more functional board.
*A well-designed PCB layer stackup protects internal layers from noise and other damaging exterior forces.
*Good layer stack design also helps to minimize radiation from your electronic gadget. You need to understand that a poor design with resistance mismatches can lead to EMI radiation.
*PCB layer stack ups can help reduce manufacturing costs because you can place multiple circuits onto a single board.
Layer Stackups for Common PCBs
When it comes to PCBs, there are several varieties to choose from. You can have single-layer PCBs, double-layer PCBs, or multiple-layer PCBs. With several choices, it might be a bit confusing to select.
But no matter which board you pick, every circuit board must have the essential foundation and consist of a number of materials that are laminated together. Below are the basic layer stacks for commonly printed circuit boards.
1. Substrate layer
A substrate layer is a foundation where a printed circuit board is built. Thus, the substrate layer has physical, thermal, and electrical properties. In other words, the substrate is the physical material that holds the components and traces.
Picking the right substrate is the first step toward building a quality PCB. This is because the characteristics of the substrate affect how the board performs. For example, a rigid substrate adds durability and strength but a flexible substrate allows more design options.
The most common form of substrate used is fiberglass. However, since the PCB industry has evolved, manufacturers are using different types of substrates such as flexible materials.
2. Copper layer
After the substrate, next is the copper layer. It is a foil that is laminated to the board using heat. And when people talk of different layered PCBs, they refer to the number of copper layers that a board consists of.
A single-layer PCB has one layer that consists of material on one side of the board. But a double-layer PCB has copper and components on both sides of the board while a multilayer PCB, there are several copper layers.
It is important to note that the copper layer on the circuit board depends on the power the PCB should withstand. Therefore, PCBs that should handle high power throughout need to have a thicker copper layer than others.
3. Soldermask layer
The soldermask layer is placed on top of the copper layer. This is the layer that gives the circuit board a green color. The main aim of the soldermask layer is to insulate the copper layer and ensure there are no contacts with metal or elements of the board. This is because some traces can disrupt the copper traces.
The Soldermask layer is vital for the manufacturing process. This is because the elements are soldered onto the board. Moreover, the user can solder the components at the right places.
4. Silkscreen layer
The silkscreen is another important layer of a circuit board. It is applied to help people understand the board and functionality of various LEDs and pins. Thus, numbers, letters, and symbols are added to the board.
Common types of PCB layer stackup
There are different types of PCB layer stack ups to choose from. However, the most important thing is to know and understand them so that you can choose the right design. There are 2-layer, 4-layer, 6-layer, 8-layer, and 10-layer.
The number of layers you need is determined by the size of the circuit, board size, and EMC requirements for the circuit board. Below are the common types of layer-stackups you need to know.
4-layer PCB
In terms of PCB stackups, 4-layer is among the common ones. The boards have 4-layers that route electrical signals. The layers are sandwiched together, where there is a top and bottom layer, and two inner layers contained between them.
However, the top and bottom layers are where the elements and routing are positioned. Since the inner layers cannot make the connections, they are used for signal routing or power planes.
This is vital as it enhances the quality of trace signals and helps to reduce EMI emissions. The two inner layers are separated from one another with a core, while the top and bottom layers are separated from the inner ones by prepreg.
Thus, we have the Top layer, Prepreg, Inner layer 1, Core, Inner layer 2, Prepreg, and Bottom layer.
6-Layer PCB
A 6-layer PCB is a 4-layer PCB with two additional layers. Generally, the layers are arranged as Top layer, prepreg, Ground plane, core, Route layer, prepreg, Route layer, core, Power plane, prepreg, and Bottom layer.
10-Layer PCB
If the design needs six routing layers, the best option is to look into a 10-layer board. This is because a 10-layer board stack has six signal layers and 4 planes. Also, there is a tight coupling between the signal and return planes.
A 10-layer design is arranged as follows: Signal layer 1, Ground plane, Signal layer 2, Signal layer 3, Power plane, Ground plane, Signal layer 4, Signal layer 5, Power plane, and Signal layer 6.
Bottom-line
In modern and complex electronic devices, PCB stackup is essential. This is because it places large circuits in a small space. Even though manufacturing and design costs may increase, the improvements and functionality is worth the cost.
However, no matter the number of layers you need, you need to go for an experienced PCB supplier. You need a supplier who will deliver quality circuit boards that meet the required standards.
Company name: Shenzhen Panshun PCB Co.,Ltd
Company: Room 316, No. 1, Nanbo Avenue, Tangwei Community, Fuhai
Address:
Street, Baoan District, Shenzhen China
Phone: +86 147 3743 9020
Disclaimer:
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Source: Story.KISSPR.com
Release ID: 446002