Multilayer board

Common Applications of Multi-Layer PCBs:

✅Computers & Servers – Motherboards, GPUs, and high-speed processors.

✅Consumer Electronics – Smartphones, tablets, and gaming consoles.

✅Telecommunication Equipment – 5G networks, routers, and satellite systems.

✅Automotive Electronics – ADAS, infotainment systems, and EV controllers.

✅Medical Devices – MRI, ultrasound, and wearable health monitors.

✅Industrial & Mechatronic Equipment – Robotics, automation, and power distribution systems.

 

 

 

Advantages of Multi-Layer PCBs

Higher Circuit Density	Allows more components and connections in a compact space.
Smaller & Lighter Design	Reduces PCB size for advanced, compact devices.
Improved Electrical Performance	Lower signal interference and better power distribution.
Increased Design Flexibility	Supports high-speed and high-frequency circuits.
Better Heat Dissipation	Evenly distributes heat across multiple layers.

 

 

 

Multi-Layer PCBs Manufacturing Process

The manufacturing of Multi-Layer PCBs is more complex than single- and double-layer PCBs due to multiple copper layers and precise alignment requirements. Below is a step-by-step process:

1.PCB Design & Layout

Circuit design is created using PCB CAD software (e.g., Altium Designer, Eagle, KiCad).

The design includes multiple copper layers, vias, and power/ground planes.

Gerber files are generated for fabrication.

2.Material Selection & Inner Layer Preparation

Core Material: Usually FR4, polyimide, or Teflon for high-frequency applications.

Copper-clad laminate is cleaned to ensure proper adhesion.

Photoresist Application: A UV-sensitive film is applied to the inner layers.

3.Inner Layer Imaging & Etching

The circuit pattern is transferred onto inner layers using UV light exposure.

Etching: Excess copper is removed using a chemical solution.

Photoresist Stripping: The remaining protective layer is removed.

4.Layer Alignment & Lamination

Inner layers are aligned with the outer layers.

Prepreg (insulating layers) and core layers are stacked.

The layers are pressed together using high-temperature and high-pressure lamination.

5.Drilling (Via Hole Creation)

CNC Drilling: Creates holes for through-hole, blind, and buried vias.

Laser Drilling (for HDI PCBs): Used for micro-vias in high-density boards.

6.Plated Through-Hole (PTH) Process

Copper electroplating coats the drilled holes to create electrical connections between layers.

 

7.Outer Layer Imaging & Etching

Similar to inner layer etching, but applied to the outer layers.

UV exposure, etching, and cleaning to form conductive traces.

8.Solder Mask Application

Solder mask (green, blue, or black) is applied to protect the copper traces from oxidation and solder bridging.

9.Silkscreen Printing (Optional)

Labels, component markings, and logos are printed for identification.

10.Surface Finishing

Enhances solderability and protects copper:

HASL (Hot Air Solder Leveling) – Cost-effective.

ENIG (Electroless Nickel Immersion Gold) – High reliability.

OSP (Organic Solderability Preservative) – Lead-free option.

11.Profiling & Cutting

PCBs are cut into final dimensions using CNC routers or V-grooving machines.

12.Electrical Testing & Quality Control

Automated Optical Inspection (AOI) – Detects defects in PCB traces.

Flying Probe or Bed of Nails Testing – Ensures electrical continuity.

13.Final Cleaning, Packaging & Delivery

PCBs are cleaned to remove contaminants.

Inspected, packed, and shipped for assembly (PCBA) or direct use.