A four-layer printed circuit board

A four-layer printed circuit board with ENIG finish

A 4-layer printed circuit board uses the ENIG process, which aims to form a nickel-gold layer on the circuit surface that is color-stable, bright, smooth, and offers excellent solderability.

Description

ENIG (Electroless Nickel Immersion Gold) Process Overview

The ENIG (Electroless Nickel Immersion Gold) process mainly consists of four stages: pre-treatment (including degreasing, micro-etching, activation, and post-immersion), nickel deposition, gold deposition, and post-treatment (waste gold rinsing, DI water rinsing, and drying).

Main Features of 4-Layer Printed Circuit Boards

  • Multi-layer structure: The 4-layer structure provides higher electrical performance and stronger anti-interference capability, making it suitable for complex circuit designs.
  • Smooth surface: The ENIG surface is smooth and bright, suitable for fine-pitch components and high-density packages such as BGA.
  • Excellent solderability: The gold layer offers excellent solderability, improving soldering quality and assembly reliability.
  • Strong oxidation resistance: The nickel-gold layer effectively prevents copper oxidation, extending the PCB’s service life.
  • Superior electrical performance: The multi-layer design helps with signal integrity and high-speed signal transmission.

Main Applications of 4-Layer Printed Circuit Boards

  • Communication equipment.
  • Computer and server motherboards.
  • Industrial control systems.
  • Medical electronic devices.
  • Automotive electronics.
  • High-end consumer electronics.