In electronic engineering, heat dissipation is a precise physical metric rather than a descriptive concept. When power density exceeds 20W/cm², the physical properties of the substrate directly dictate the product's failure rate and field return rate.

1. Case Study: Thermal Failure Analysis in 5G Base Station PA

• Background: An RF engineer utilized high-frequency PTFE boards in a 5G mmWave module design.
• Problem: After 15 minutes of operation, the chip junction temperature reached 115°C, causing significant signal gain drift and triggering thermal shutdown.
• Solution: Substrate replaced with 0.5mm Aluminum Nitride (AlN) ceramic PCB.
• Thermal Conductivity Comparison:
  • PTFE (filled): ~0.6-0.8 W/m·K
  • AlN Substrate: 180 W/m·K
• Result: Under identical power input, the junction temperature dropped from 115°C to 68°C.
• Reliability Gain: A 47°C reduction in temperature correlates to a 4.5x extension in device lifespan based on the Arrhenius Model.

[Insert Figure 1: Thermal Imaging Comparison]

• Left: FR-4/PTFE substrate showing localized hotspots (Red/Purple).
• Right: AlN substrate showing rapid heat spread (Blue/Green), eliminating heat accumulation.

2. Process Capability: Micron-Level Precision of DPC (Thin Film)

For sensors requiring laser-drilled vias or fine-line circuitry, traditional thick-film printing or mechanical machining is insufficient.

• Adhesion Data: DPC (Direct Plated Copper) utilizes vacuum sputtering; metal-to-ceramic adhesion strength > 1.2 kg/cm.
• Precision Metrics:
  • Min Trace/Space: 20μm / 20μm (Supports high-density gold wire bonding).
  • Via Capability: Minimum laser drilling diameter 0.05mm (50μm).
• Surface Roughness (Ra): Post-processing Ra < 0.1μm, significantly reducing "skin effect" losses in high-frequency signals.

[Insert Figure 2: Microscopic Cross-section of DPC Circuitry]

• Visual focus: Tight interface between copper and ceramic; 100% solid copper-filled vias.

3. Power Electronics: DBC (Direct Bonded Copper) Durability

In EV inverters or IGBT modules, the ceramic substrate functions as both a heat spreader and a high-voltage insulator.

• Dielectric Strength: 0.635mm Alumina substrate provides breakdown voltage > 15kV.
• Current Load Test:
  • Thickness Advantage: DBC copper thickness is customizable up to 300μm (9oz).
  • Empirical Data: Under a 300A transient current surge, the temperature rise remains below 10°C, preventing thermal fatigue in the power module.

[Insert Figure 3: DBC Layer Structure Breakdown]

• Visual focus: Thick Copper - Ceramic Insulator - Thick Copper layers with dimension callouts.

4. Objective Constraints in Ceramic PCB Manufacturing

To avoid design-stage cost traps, engineers must consider the following physical limitations:

• Dimensional Limits: Due to ceramic brittleness, panel sizes are typically restricted to 114mm x 114mm or 138mm x 190mm. Larger panels increase the risk of micro-cracking during logistics and assembly.
• Singulation Design: Traditional V-scoring is not applicable. Laser Scribing or full laser cutting is required to prevent edge micro-fractures from expanding during thermal cycling.
• Lead Time: Material sourcing for specific ceramic grades takes 3-5 days. With specialized processing, the standard lead time is 10-15 working days.

Summary: Requirements for Accurate Quotation

To receive a DFM (Design for Manufacturability) review and quote, please provide the following technical data:

1. Material: Al₂O₃ (96% or 99%) or AlN?
2. Substrate Thickness: 0.38mm / 0.5mm / 0.635mm / 1.0mm?
3. Process: DPC (High Precision) or DBC (High Current)?
4. Copper Weight: 35μm, 70μm, or 300μm+?
5. Special Requirements: Copper-filled vias or specific surface finishes (ENIG/ENEPIG)?