MultiLayer PCB
PCB Production Solution for Industrial IO Module
Core Parameters
This PCB is designed for industrial IO module applications, requiring high reliability, signal integrity, and mechanical stability in harsh environments.
| Parameter | Specification | Purpose |
|---|---|---|
| Substrate | FR4 (High Tg) | Stable dielectric performance for industrial temperature range |
| PCB Thickness | 1.600mm | Meet mechanical assembly and warpage tolerance |
| Surface Finish | Immersion Gold | Enable fine-pitch component soldering and anti-oxidation |
| Stencil Thickness | 0.1mm | Optimize solder paste release for dense component layout |
| Solder Paste Thickness (BOT) | 0.125mm | 0.025mm thicker than stencil for robust solder joints |
| CBA Thickness | 1.600mm | Controlled board assembly thickness for mechanical fit |
Design Scheme
Structure & Function
- Multi-layer design integrating industrial IO interfaces, power management circuits, and signal conditioning modules
- Signal integrity optimization for analog/digital mixed-signal paths (controlled impedance, reduced crosstalk)
- Power plane layout with dedicated GND/VCC layers for stable power delivery to high-current components
- Mechanical robustness design with edge stiffeners and precise mounting hole tolerances
Drilling & Routing Requirements
- High-density via array (microvias and through-holes) for multi-layer interconnection, total holes >500
- Precision Control: ±0.05mm hole position accuracy, 0.2mm minimum drill diameter
- Trace width/spacing: 6/6mil for signal lines, 10/10mil for power lines
Design Documentation
PCB Top Layer Layout
Top layer with dense component placement and IO interfaces
PCB Bottom Layer Layout
Bottom layer focusing on power distribution networks
PCB Multi-Layer Composite View
Composite view illustrating inter-layer connections
Production Process
Multi-Layer Lamination
- • FR4 core + prepreg layers laminated to 1.6mm
- • Precise layer alignment (<±0.03mm) for inter-layer vias
- • Thermal curing optimized for Tg stability
- • Controlled pressure (25-30 kgf/cm²) during lamination
Immersion Gold Finish (7-Step Process)
SMT Assembly
- • 0.1mm stencil with laser-cut apertures
- • 0.125mm solder paste thickness (BOT side)
- • Reflow profile: Preheat (150-170℃/60s)
- • Reflow profile: Soak (170-190℃/40s)
- • Reflow profile: Peak (235-245℃/10s)
- • Post-reflow inspection: X-ray + AOI
Immersion Gold Process Key Notes
Quality Control
In-Process Inspection
After drilling
X-ray inspection + CMM measurement (verify hole position, diameter, and plating integrity)
After etching
AOI (inspect trace width/spacing, shorts, opens, and copper uniformity)
After immersion gold
XRF (gold/nickel layer thickness); solderability test (wetting balance method)
Final Verification
Electrical Tests
Bed-of-Nails test (continuity, insulation resistance); impedance test (controlled impedance lines)
Reliability Tests
Thermal cycling: -40℃~+85℃, 1000 cycles
Humidity test: 85℃/85%RH, 500h
Mechanical shock: 50G, 11ms
Summary
The production of MultiLayer PCB ensures reliability for industrial applications through:
- Design: Prioritizing "mixed-signal integrity + power delivery stability" for industrial IO scenarios
- Manufacturing: Controlling "multi-layer lamination precision, 7-step immersion gold process (5-10μm nickel + 2-3μm gold), and SMT process parameters"
- QC: Full-process inspection covering drilling, etching, plating, and final electrical/reliability verification