6 Layer PCB Board-Stackup, Thickness, Fabrication, and Price

1. The number of PCB layers is different: a 6-layer PCB has two more layers than a 4-layer PCB, making a 6-layer PCB more complicated than a 4-layer PCB.
2. The stacking structure is different: there are two additional signal layers between the planes of the 6-layer PCB stack, which also increases the procurement cost of the 6-layer PCB stack.
3. The impedance characteristics are different: If we compare the 6-layer PCB stack with the 4-layer PCB stack, the impedance is lower.
4. A 6-layer PCB stack-up has more space and therefore comes with less wire connection on each layer than a 4-layer PCB stack-up.
5. 6 layer PCB stack-up works more efficiently and performs better than a 4-layer PCB stack-up.

Many factors affect the price of 6-layer PCB, which are summarized as follows:

1. The larger the size of the 6-layer PCB, the higher the manufacturing cost;
2. The price of a 6-layer PCB with unique production processes such as buried blind vias will be higher;
3. 6-layer PCB materials, such as High Tg170 and High Tg180 boards, will be more expensive than ordinary FR4 boards;
4. Quantity and quality of components: As the number of components increases, the assembly price of the 6-layer circuit board will also increase; if the quality of the components selected is better, the cost will be more.

• Step 1. Editing the schematic diagram: After drawing the schematic diagram, don’t forget to check the error. And check the package manager to check the component package.
• Step 2. Create a new PCB file, set the 6 layer PCB layer structure: After creating a new one, you can import the schematic netlist to a PCB file for 6-layer PCB manufacturing.
•  Step 3. Layout: The main principle of layout in 6-layer PCB manufacturing is to partition well. Moreover, the partition of analog devices and digital devices，Which can reduce interference，Because the interference generated by digital signals is significant, and the anti-interference is also vital.
• Step 4. Production of ground plane: 6-layer PCB manufacturing has two layers of ground: AGND and DGND. Generally, both are separated and located on the second and fourth layers, respectively. So the operation of the ground network is relatively easy. The ground network pins of the top and ground components are led out with wires and connected to the corresponding network through the via hole. Use as few pads as possible during the connection process because the pads will bring capacitance effects and increase interference.
• Step 5. Production of power plane: Since the multilayer PCB board will not have only one working voltage value, the power layer should be divided.
• Step 6. Routing: Make the power layer and ground layer well. And then, you can route the signal lines. When routing during 6-layer PCB manufacturing, the critical high-speed signal line is best to go to the inner signal layer.
• Step 7. DRC inspection: This step is very important for 6-layer PCB manufacturing. After the PCB drawing is completed, it must be checked.

PCB Stack-up describes the construction of a multilayer circuit board in sequential order. It provides vital information like material thickness and copper weights required to manufacture a PCB. Stack-ups are also referred to as build-ups. The stack-up also gives the details of trace width for different controlled impedance traces such as 50ohms, 100ohms differential.

PCB stack-up is mainly composed of metal foil, prepreg, and copper-clad laminate (core).

• Metal foil: copper is the most commonly used metal foil in PCB structures.
• Prepreg: it is a kind of interleaved glass cloth impregnated in epoxy resin. The resin remains semi-cured.
• Copper-clad laminate(CCL): one or more prepreg layers are bonded with the top and bottom copper foils to form a copper-clad laminate. CCL is also known as the core.
• Power and ground layers in PCB stack-up: The power plane is a copper layer connected to the power supply. It is often designated as VCC in PCB design. The primary function of the power plane is to provide a steady voltage supply to the printed circuit board. In the multilayer PCBs, if a component needs to draw power, it is connected to the via that makes contact with the power plane. Similarly, the ground plane is a plane of flat copper connected to the common ground point in the PCB.

The PCB lamination is the process of placing the stack-up under high temperature and pressure to bond prepreg and copper foil to the base PCB inner layers. The temperature and pressure values are mentioned in the datasheets of the chosen PCB materials.

PCB Laminator

The thickness of the PCB board mainly depends on copper thickness, the material used, the number of layers, the operating environment, and other factors. The standard thickness of a conventional PCB is about 62 mils (1.57 mm). Nowadays, with the increase of the weight and number of copper layers in various applications, PCB becomes more complex. Therefore, PCBs tend to become thicker. According to the customer’s requirements, PCB manufacturers are now manufacturing two new standard thickness PCBs, 93 mils (2.36 mm) and 125 mils (3.17 mm) (150% and 200% of the old standard thickness).

With the progress of electronic technology, electronic equipment has become smaller and thinner. However, more and more electronic components and routing need to be used, so it has become more complex.

The single-layer circuit board has been unable to meet the growing complex needs. Therefore, it is necessary to increase the number of layers in the stack of circuit boards to solve this problem.

Increasing the number of layers on the printed circuit board has the following advantages:

1. Multilayer circuit boards can adapt to the complex circuit design required by modern electronic equipment. For example, the circuit design of a 6-layer circuit board has much more significant advantages than that of a double-sided circuit board;
2. Multilayer circuit board means that the circuit board is thicker, so it is more durable than a single-sided circuit board;
3. The manufacture of Multilayer PCB is more precise, and its quality is higher than that of single and double-sided PCB;
4. Multilayer circuit board simplifies the design of electronic equipment and further reduces the weight of electronic equipment.