Ceramic PCB

Common materials include aluminum oxide (Al₂O₃, 60%-96% purity), aluminum nitride (AlN), and beryllium oxide (BeO, gradually replaced due to toxicity). 96% aluminum oxide accounts for over 60% of applications.

Al₂O₃ (96%) is approximately 25W/m・K, AlN reaches 170-230W/m・K, and beryllium oxide (BeO) is about 250W/m・K.

Aluminum oxide (6-7 ppm/°C), aluminum nitride (4.5 ppm/°C), much lower than FR4's 18-22 ppm/°C.

At room temperature, the insulation resistance of Al₂O₃ substrates is >10¹⁴Ω, and that of AlN substrates is >10¹³Ω.

The dielectric constant of 96% aluminum oxide is about 9.8 (1MHz), and that of AlN is about 8.5 (1MHz).

Operating temperature: -55℃~300℃, can withstand short-term high temperatures exceeding 800℃.

Mohs hardness is 6-9, aluminum oxide (96%) reaches level 7, with high processing difficulty.

Al₂O₃ (96%) is approximately 3.85g/cm³, and AlN is about 3.26g/cm³.

Low dielectric loss (tanδ＜0.002), small signal transmission delay.

Water absorption rate <0.01%, significantly lower than organic substrates (FR4 water absorption rate 0.15%-0.2%).

Thick-film process (screen printing), thin-film process (sputtering/evaporation), co-firing process (HTCC/LTCC), etc.

HTCC sintering temperature is 1500-1600℃, LTCC is 850-900℃; LTCC can integrate passive components with higher cost.

Thin-film process can achieve line width/spacing of 10μm/10μm, and thick-film process is about 100μm/100μm.

The minimum hole diameter for laser drilling is 50μm, and for mechanical drilling is 100μm.

Direct bonding copper (DBC), active metal brazing (AMB), thick-film printing.

Common copper layer thickness is 0.1-0.3mm, up to 0.5mm at maximum.

Bonding strength >25N/mm, thermal cycle times exceed 1000 times (-40℃~150℃).

Thin-film process Ra <0.2μm, thick-film process Ra <1μm.

Laser cutting, dicing, mechanical cutting. Laser cutting accuracy is ±25μm.

Thin-film process yield is about 85%-90%, and thick-film process is about 90%-95%.

Avoid acute angle design, fillet radius ≥0.2mm; add heat dissipation holes in areas with concentrated thermal stress.

Through flip chip bonding, wire bonding, eutectic welding, etc. Flip chip bonding has a thermal resistance as low as 0.5℃/W.

5G base stations (signal loss <0.5dB/cm@28GHz), radar systems, satellite communications.

Reduce thermal resistance. Using AlN substrates in IGBT modules can reduce thermal resistance to 1.5℃/W.

Can be used in engine control units (ECUs), with excellent high-temperature resistance and vibration resistance.

High-power LED heat dissipation substrates, with thermal resistance reducible to below 3℃/W.

For 1oz copper foil under a 10℃ temperature rise, a 1mm line width can carry approximately 2A.

Stacked through co-firing processes, LTCC can achieve more than 100 layers at most.

The flexural strength of Al₂O₃ (96%) >300MPa, and that of AlN >350MPa.

Radiation resistance (can withstand 10⁶Gy dose), lightweight (density about 1/3 of metal substrates).

Thermal cycle test (-40℃~125℃, 1000 times), damp heat test (85℃/85% RH, 1000h).

Metallization layer cracking (Al₂O₃ DBC substrate failure cycle times about 500-800 times).

1mm thickness can withstand ≥5kV, partial discharge inception voltage >2kV.

Tape peeling test (3M 610 tape), no metal layer detachment.

Under normal working conditions, it can reach more than 10 years, and in high-temperature and high-humidity environments, it is shortened to 5 years.

X-ray detection, ultrasonic scanning microscope (C-SAM), with a resolution of up to 10μm.

Sinusoidal vibration 5-2000Hz, acceleration 5g, lasting 2 hours without cracks.

96h salt spray test (5% NaCl solution), no corrosion of the metallization layer.

Human body model (HBM) >2kV, machine model (MM) >200V.

-40℃~150℃, conversion time <10s, cycle times 500 times.

The cost of ceramic substrates is 5-10 times that of FR4, mainly due to complex materials and processes.

Mass production, process optimization (such as using thick film instead of thin film), selecting low-cost materials (such as 60% aluminum oxide).

Better insulation performance (metal substrates need insulation layers), and the coefficient of thermal expansion is more matched with chips.

Aluminum oxide (60%) < aluminum oxide (96%) < aluminum nitride < beryllium oxide (ban trend).

Material type, process complexity, number of layers, size, order quantity.

Can be achieved through rigid-flex process, with a cost increase of 20%-30%.

Accounts for about 15%-20% of the total cost, and the improvement of yield can significantly reduce it.

When the order quantity exceeds 5,000 pieces, the unit cost decreases significantly.

Long development cycle (3-6 months), high mold cost (about 50,000-100,000 yuan).

The heat dissipation performance of AlN substrates is 3 times that of aluminum-based PCBs, but the cost is 4 times higher

Fixed by screws or bonded with thermal conductive adhesive (thermal resistance <1℃/W).

Reflow soldering peak temperature: 240-260℃, duration <60s.

Reworkable, but high temperature may cause ceramic cracking with a success rate of about 70%.

Clean with IPA (isopropyl alcohol) ultrasonic cleaning for <10min.

Maintain operating environment humidity at 40%-60% and wear anti-static wristbands.

Select materials with similar thermal expansion coefficients and fill gaps with thermal conductive silicone grease.

Not recommended, as thermal stress may cause ceramic cracking.

Torque for M3 screws: 0.8-1.2N・m to avoid stress concentration.

Detect hotspots via infrared thermal imaging and check connectivity through resistance testing.

Storage: humidity <30% RH, temperature 20-25℃, avoid mechanical impact.

IPC-6012 (Performance Specification for Rigid Printed Boards), MIL-P-55110 (Military Standard).

UL certification (flame retardant), RoHS certification (hazardous substance-free), ISO 9001.

Meet MIL-STD-810G environmental testing with strict vibration and impact resistance requirements.

Require AEC-Q100 (chips) and AEC-Q200 (passive components) certifications.

Comply with EU REACH regulations, restricting the use of hazardous substances like lead and cadmium.

UL 94 V-0 rating (no flame spread), oxygen index >30%.

Comply with ISO 13485 medical device quality management system.

Require AS9100 aerospace quality management system certification.

Comply with EN 55032 electromagnetic radiation standards, conducted emissions <40dBμV.

Third-party certification bodies: SGS, TÜV, Intertek.

Inspect bonding process (e.g., DBC copper foil oxidation) and reprocess the surface.

Fill minor cracks with epoxy resin; replace the substrate for severe cracks.

Adjust soldering temperature profile and control flux activity (RA grade).

Optimize wiring, use low dielectric constant materials, and add grounding layers.

Inspect thermal conduction paths and test thermal resistance (target <2℃/W).

Uneven sintering process or insufficient thermal stress relief; optimize the manufacturing process.

Clean with plasma to remove organic residues.

Insulation resistance test (1000V DC) to locate leakage points.

Strengthen protective coatings (e.g., nickel-gold plating) and avoid corrosive gases.

Increase substrate thickness (≥0.5mm) and optimize corner design.

Thinning (<0.1mm), integration (3D packaging), cost reduction.

Silicon nitride (Si₃N₄), with high thermal conductivity (100W/m・K) and strength.

Ceramic 3D printing has realized complex heat dissipation structures with a precision of 50μm.

Optimize thermal distribution via simulation algorithms, shortening the design cycle by 30%.

Used in SiC power modules with an annual market growth rate of over 20%.

Low dielectric loss meets high-frequency communication needs, with demand expected to grow 50% by 2025.

Water-based thick-film pastes replace organic solvents to reduce VOC emissions.

Difficulty in matching thermal expansion coefficients, requiring buffer layer materials.

EUV lithography achieves 10nm-level circuits, currently in the laboratory stage.

High stability at low temperatures may make them carriers for quantum chips.

Maximum temperature resistance: 800℃, requiring high-temperature metallization materials (e.g., molybdenum-manganese method).

Withstand 100MPa pressure and achieve IP68 protection via potting.

Use radiation-resistant ceramics (e.g., silicon carbide) to shield neutron radiation.

Control characteristic impedance (50Ω) and reduce dielectric loss (tanδ <0.001).

Adopt micro-channel heat dissipation structures with heat flux density up to 100W/cm².

Surface passivation required, complying with ISO 10993 biological testing.

High temperature resistance and insulation, improving system efficiency by 1%-2%.

Meet high-voltage DC (HVDC) insulation requirements, voltage withstand ≥10kV.

Use shock-absorbing brackets and avoid external excitation frequencies for natural frequency.

Integrate with MEMS chips to achieve miniaturization and low-power design