Standard 4-Layer PCB Structure, Manufacturing and Cost2023-02-03
With the gradual development of electronic products to high-speed, high-capacity, multi-functional, miniaturization, the application of multilayer PCB becomes more and more common.
For PCB manufacturing, the more layers, the more manufacturing processes, the higher the corresponding cost. So multilayer PCBs are used more in advanced circuits. 4-layer PCBs are also widely used, this article will detail the structure, manufacturing and its cost.
What is a 4-layer PCB?
Four layers in a 4-layer pcb board is divided into two outer layers and two inner layers.
- Signal layer (top layer)
- Power layer (middle layer)
- Ground layer (middle layer)
- Signal layer (bottom layer)
Typically, the inner layer is used for power and GND, while the outer layer is used for signal routing as well as component placement.
4-Layer PCB Advantages
4-layer PCBs have more obvious advantages over single-layer PCBs, double-layer PCBs, such as
1. More components can be placed
2. Suitable for compact designs
3. Optimized signal routing
4. Better EMI shielding
5. Thermal control
Standard 4-layer PCB laminated structure design
A: Top layer (signal layer), Inner layer (power layer), Inner layer (ground layer), Bottom layer (signal layer)
B: Top layer (power layer), Inner layer (signal layer), Inner layer (signal layer), Bottom layer
C: Top layer (signal layer), Inner layer (ground layer), Inner layer (power layer), Bottom layer (signal layer)
4-layer PCB manufacturing process
- Open material
- Make L3 layer circuit
- Press fit (L3 and L4 layer substrate with L2 layer copper skin press fit)
- Drill L2-L4 layer blind hole
- Copper plating
- Resin plug hole
- Copper reduction
- Do L2 layer circuit
- Pressing (L2-L4 layer and L1 layer copper skin pressed together)
- Outer layer circuit (do L1 and L4 layer circuit)
- After process normal production
4-layer PCB cost
4-layer PCB and any kind of PCB are the same, there is no a standard cost, because many factors will affect the price. The main factors include.
- Material (different TG values require different prices)
- Vias types and quantity (such as buried vias, buried vias)
- Copper thickness
- Surface treatment (normally is HASL, if you choose to ENIG then the price will increase)