multilayer-layer PCB

multilayer-layer PCB

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What is multilayer-layer PCB?

Multilayer PCB refers to printed circuit boards with three or more conductive copper layers laminated together with insulating materials. These boards feature multiple layers of circuitry interconnected through plated vias, enabling highly complex designs in compact form factors. Multilayer PCBs range from simple 4-layer constructions to sophisticated boards with 20, 30, or even more layers for the most demanding applications.

we manufacture high-quality multilayer PCBs from 4 to 30 layers, serving customers across diverse industries worldwide. With over 24 years of experience in advanced PCB fabrication, we have the expertise and equipment to handle even the most challenging multilayer designs with precision and reliability.

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Multilayer PCB Structure

A typical multilayer PCB consists of:

Outer Layers (Surface Layers)

  • Top and bottom copper layers
  • Component placement and primary routing
  • Solder mask and silkscreen application
  • Typical thickness: 1-3oz copper

Inner Layers (Core Layers)

  • Signal routing layers
  • Power distribution planes
  • Ground reference planes
  • Typical thickness: 0.5-2oz copper

Dielectric Layers

  • FR-4 epoxy glass fabric (most common)
  • High-Tg materials for thermal stability
  • Low-loss materials for high-frequency applications
  • Prepreg and core materials

Plated Through-Holes (PTH)

  • Vias connecting different layers
  • Through-hole component mounting
  • Copper plated for electrical connection

Advanced Via Structures

  • Blind vias (connect outer layer to inner layer)
  • Buried vias (connect inner layers only)
  • Microvias (laser-drilled, <0.15mm diameter)
  • Stacked and staggered via configurations

Types of Multilayer PCB by Layer Count

4-Layer PCB

  • Entry-level multilayer
  • Signal/Ground/Power/Signal configuration
  • Most cost-effective multilayer option
  • Suitable for moderate complexity designs
  • Common in consumer electronics

6-Layer PCB

  • Enhanced routing capacity
  • Multiple ground/power plane options
  • Better EMI performance
  • Improved signal integrity
  • Industrial and automotive applications

8-Layer PCB

  • High-density interconnect capability
  • Complex power distribution
  • Superior EMI shielding
  • High-speed digital design support
  • Telecommunications and computing

10-Layer PCB

  • Advanced signal routing
  • Multiple voltage rail distribution
  • Excellent thermal management
  • High-reliability requirements
  • Medical and aerospace applications

12-16 Layer PCB

  • Very high component density
  • Complex impedance control
  • Multiple high-speed interfaces
  • Server and networking equipment
  • Advanced computing systems

20+ Layer PCB

  • Extreme complexity designs
  • Backplane and motherboard applications
  • High-performance computing
  • Telecommunications infrastructure
  • Mission-critical systems

FAST-PCB Multilayer Capabilities

Layer Count Range

  • Standard: 4-20 layers
  • Advanced: 22-32 layers
  • Special capability: Up to 64 layers
  • Custom layer counts available

Board Specifications

  • Minimum size: 10mm x 10mm
  • Maximum size: 500mm x 600mm
  • Thickness range: 0.4mm – 6.0mm
  • Standard thickness: 1.6mm, 2.0mm, 2.4mm
  • Thickness tolerance: ±10% (standard), ±5% (precision)

Copper Weight Options

  • Outer layers: 0.5oz – 6oz (17.5μm – 210μm)
  • Inner layers: 0.5oz – 3oz (17.5μm – 105μm)
  • Mixed copper weights in same board
  • Heavy copper capability for power applications

Trace and Space

  • Standard: 4/4 mil (0.1/0.1mm)
  • Fine line: 3/3 mil (0.075/0.075mm)
  • Ultra-fine: 2.5/2.5 mil (0.063/0.063mm)
  • Inner layer: 4/4 mil minimum

Via Technology

  • Through-hole vias: Standard PTH
  • Blind vias: Outer to inner layer connection
  • Buried vias: Inner layer to inner layer
  • Microvias: Laser-drilled, 0.1-0.15mm diameter
  • Via-in-pad: Resin or copper filled
  • Stacked and staggered microvias
  • Aspect ratio: Up to 16:1

     

  • Minimum Hole Sizes

    • Mechanical drill: 0.15mm (6 mil)
    • Laser drill (microvia): 0.1mm (4 mil)
    • Standard via: 0.2-0.3mm
    • Maximum hole: 6.0mm

Impedance Control

  • Single-ended: 25Ω – 120Ω
  • Differential pairs: 85Ω – 120Ω
  • Tolerance: ±5%, ±7%, ±10%
  • Microstrip and stripline configurations
  • TDR testing and documentation
  • Impedance test coupons included

Materials Available

  • Standard FR-4 (Tg 130-140°C)
  • Mid-Tg FR-4 (Tg 150-170°C)
  • High-Tg FR-4 (Tg 170-180°C)
  • Halogen-free materials
  • Rogers materials (RF/microwave)
  • Isola materials
  • Nelco materials
  • Low-loss laminates
  • High-frequency substrates

Surface Finish Options

  • HASL (Hot Air Solder Leveling)
  • Lead-free HASL
  • ENIG (Electroless Nickel Immersion Gold)
  • ENEPIG (for wire bonding)
  • Immersion Silver
  • Immersion Tin
  • OSP (Organic Solderability Preservative)
  • Hard Gold (edge connectors)
  • Soft Gold (wire bonding)

Special Features

  • Controlled depth drilling
  • Back drilling for stub removal
  • Countersink and counterbore holes
  • Edge plating
  • Castellated holes
  • Copper coin embedding
  • Cavity PCB
  • Step and repeat panels

Quality Standards

  • IPC-6012 Class 2 and Class 3
  • IPC-A-600 acceptance criteria
  • UL certification
  • RoHS and REACH compliant
  • ITAR registered facility (if required)