What is the manufacturing process of ceramic pcb?

Ceramic PCB Manufacturing Process

Ceramic printed circuit boards are high-performance electronic components characterized by high temperature resistance, high frequency, high voltage, and high reliability. They are widely used in aerospace, military, telecommunications, and other fields. The following outlines the typical manufacturing process of ceramic PCBs.

1. Raw Material Preparation

The performance of ceramic PCBs heavily depends on the purity, particle size distribution, and chemical stability of the ceramic powder substrate. Therefore, the first step is the careful selection and treatment of base materials.

Raw Materials Composition:

• Ceramic powders: such as aluminum oxide (Al₂O₃), aluminum nitride (AlN), zirconium oxide (ZrO₂), magnesium oxide (MgO), with purity exceeding 99%;

• Organic binders: such as PVA (polyvinyl alcohol), polyethylene glycol, used for temporary binding;

• Solvents and additives: used to adjust flowability and film formation, including ethanol, acetone, butanone, dispersants, etc.

Process Flow:
Ceramic raw material selection → ball milling and mixing → vacuum de-airing → drying and granulation → storage for use

Control Focus:

• Particle size controlled between 0.5 to 3 μm;

• Uniform distribution to prevent sintering defects like porosity or cracking;

• Strict control of moisture and impurities to avoid gas bubbles during sintering.

2. Ceramic Slurry Printing or Lamination Molding

The mixed ceramic powder, organic binder, and solvent slurry is printed onto ceramic substrates to form the required circuit patterns and component mounting locations. The forming method varies with different ceramic PCB types:

• A. Thick Film/Thin Film Printing (for single-layer ceramic boards):
  Ceramic or conductor slurry is printed on the substrate via screen printing or inkjet printing;
  Functional patterns like circuits, pads, capacitive layers, and inductive patterns are formed.

• B. Green Tape Lamination (for LTCC/HTCC):
  Ceramic powders are mixed into “green tapes” and laminated via hot pressing to form multilayer structures;
  Conductive circuits are printed on each layer, with vias created to establish electrical connections.

Core Equipment:

• Automatic screen printers

• Precision laminating alignment machines

• Vacuum presses / isostatic presses (the latter for complex shapes)

3. Drying and Pre-curing

Printed or laminated substrates are placed in a temperature-controlled oven for low-temperature drying at 80~120°C for 1-2 hours.
This step evaporates solvents in the slurry, enhancing initial pattern stability and preventing defects such as bubbles or delamination during subsequent sintering.

Key Points:

• Uniform drying with controlled temperature rise to avoid internal stress buildup;

• Conducted in cleanroom or controlled environment to prevent dust contamination.

4. High-Temperature Sintering (Densification)

This is the critical step for ceramic PCB formation.

Sintering Process:

• Dried ceramic boards are placed in a high-temperature furnace following a programmed sintering curve;

• Temperatures typically range from 1300 to 1650°C;

• Sintering duration is 2-4 hours (including heating, soaking, and cooling phases);

• Furnace atmosphere can be air, nitrogen, hydrogen, or vacuum depending on ceramic type and metallization method.

Sintering Outcomes:

• Ceramic powder grains reorganize, forming a continuous, dense polycrystalline structure;

• Final boards achieve target mechanical strength, dimensional stability, thermal conductivity, and electrical insulation.

5. Surface Metallization (Conductive Circuit Formation)

After sintering, ceramic substrates are insulating and require metallization to deposit conductive layers forming the circuit patterns.

Common Metallization Techniques:

6. Soldering and Component Mounting

Following metallization and patterning, electronic components are soldered onto the circuits.

Common Techniques:

• Reflow soldering (SMD assembly)

• Laser welding, ultrasonic welding (for leads or power pins)

• Silver paste sintering (especially suitable for IGBT chip mounting)

Process Features:

• Ceramic PCBs withstand high temperatures (>800°C), compatible with various high-temperature soldering methods;

• Strong copper-ceramic bonding endows excellent thermal shock resistance and high current capacity.

7. Testing

Completed PCBs undergo rigorous inspections, including:

• Electrical Testing: Verify correct circuit connections, no shorts or open circuits, ensuring reliable operation with connected devices.

• Thermal Testing: Assess heat conduction and convection performance, crucial for PCBs exposed to high temperatures.

• Mechanical Testing: Apply bending, vibration, or other stresses to test mechanical resilience.

Whether used in satellites, electric vehicles, or medical devices, each test is critical to ensure reliable operation of ceramic PCBs in their intended applications.

8. Shaping, Cutting, and Packaging

• Shaping:
  Mechanical drilling is unsuitable for ceramics; laser processing (UV, CO₂) is employed for drilling, V-cuts, grooves, and vias with precision control.

• Cleaning and Packaging:
  Ultrasonic cleaning with deionized water;
  Drying followed by vacuum sealing;
  For sensitive products, desiccants and anti-static bags are added.