Aluminum Nitride PCB (AlN PCB)

Aluminum-Nitride PCB
(AIN PCB)

Aluminum-Nitride PCB (AIN PCB)

What is a Ceramic PCB?

Many users of PCBs (Printed Circuit Boards) find that ceramic PCBs offer significant advantages over traditional boards made from materials such as fiberglass or epoxy resin. The key benefits come from the use of ceramic substrates, which provide high thermal conductivity and a low coefficient of thermal expansion (CTE)—critical factors for improving reliability and performance in electronic circuits.

A ceramic PCB is extremely versatile and can often replace an entire traditional PCB with a simpler design and enhanced performance. These boards are widely used in high-power circuits, chip-on-board (COB) modules, LED lighting systems, and proximity sensors, where efficient heat dissipation and stability are essential.

In simple terms, a ceramic printed circuit board is a type of PCB that uses a ceramic material base or substrate—usually an inorganic dielectric—rather than the conventional fiberglass or epoxy resin base. It consists of a thin, insulating layer of ceramic combined with a conductive metal layer, delivering superior thermal management, electrical insulation, and mechanical strength for demanding electronic applications.

Advantages of Ceramic PCBs

In addition to their excellent thermal conductivity and low coefficient of thermal expansion (CTE), ceramic PCBs provide several other advantages that make them ideal for high-performance electronics.

Key benefits include:

High-Temperature Resistance – Reliable operation in environments up to 350°C, ensuring stability in extreme conditions.
High-Density Circuit Tracing – Simplifies the design and implementation of complex, compact electronic layouts.
Superior High-Frequency Performance – Low dielectric loss enables efficient signal transmission in RF and microwave applications.
Hermetic Packaging Options – Available in hermetic packages to prevent moisture absorption and improve long-term reliability.
Chemical Resistance – Strong protection against corrosion and chemical erosion in harsh environments.
Lower System Cost – Ceramic PCBs can reduce total system costs, particularly in dense circuit designs, by allowing parallel processing of multiple layers.

Ceramic PCBs – Aluminum Nitride (AlN) & Alumina (Al₂O₃)

Main Ceramic PCB Types

Ceramic PCBs are typically built with ceramic cores, with Aluminum Nitride (AlN) and Alumina (Al₂O₃) being the two most widely used materials. Both types deliver superior thermal performance compared to metal-core PCBs, since they do not require an additional dielectric layer between the core and the circuits.

1) Aluminum Nitride (AlN) PCB

High Thermal Conductivity – Typically above 150 W/m·K, often reaching 170–180 W/m·K.
Excellent Dielectric Properties – Ensures reliable electrical insulation.
Low Coefficient of Thermal Expansion (CTE) – Provides dimensional stability under temperature cycling.
Chemical Resistance – Non-reactive with semiconductor processing chemicals.
Ideal Applications – Power electronics, RF modules, LED lighting, automotive electronics, and aerospace systems.

2) Alumina (Al₂O₃) PCB

Cost-Effective Solution – A more affordable option compared to AlN.
Moderate Thermal Conductivity – Around 18–36 W/m·K, suitable for less heat-intensive applications.
Mechanical Durability – Strong and reliable for standard use cases.
Ideal Applications – Consumer electronics, sensors, and lower-power circuits where cost efficiency is critical.

Material Options: Aluminum Nitride & Aluminum Oxide

For applications requiring superior heat dissipation, Aluminum Nitride PCBs are the ideal choice, with thermal conductivity greater than 150 W/m·K. However, because AlN is more expensive, many companies opt for Aluminum Oxide (Alumina) PCBs, which offer 18–36 W/m·K while still outperforming metal-core PCBs.

Both materials eliminate the need for an electric layer between the core and the circuits, improving thermal performance. Additionally, ceramic PCBs can be manufactured with gold plating on exposed pads to prevent silver corrosion in high-sulfur environments.

Other Ceramic PCB Material Options

While Aluminum Nitride and Alumina are the most common, other advanced ceramic materials can also be used for PCB manufacturing:

Silver Traces with Glass Protection – Boost thermal conductivity up to 406 W/m·K.
Boron Nitride (BN) – Known for excellent thermal conductivity and low dielectric constant.
Beryllium Oxide (BeO) – Offers extremely high thermal performance but is less commonly used due to toxicity concerns.
Silicon Carbide (SiC) – Provides strong mechanical strength and high-temperature resistance.

Surface Finishes for Ceramic PCBs

Due to high operating temperatures, ceramic PCBs are typically not finished with OSP, HASL, or Pb-free HASL. Instead, they are often coated with:

ENIG (Electroless Nickel Immersion Gold)
ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold)

These finishes protect exposed pads and reduce the risk of silver corrosion, particularly in harsh or sulfur-rich environments.

Thermal Conductivity in Ceramic PCBs

The leading reason industries turn to ceramic PCBs is their exceptional thermal conductivity. This property gives ceramics a clear edge over traditional PCB materials like FR4 and metal-core substrates. Combined with better CTE matching and hermetic sealing, ceramics ensure long-term reliability in demanding applications.

However, ceramic substrates and boards are significantly more expensive than traditional PCB materials. For high-volume production, costs can accumulate, but for companies requiring high-power, high-frequency, and thermally demanding performance, ceramic PCBs are often the only viable solution.

How to Estimate Ceramic PCB Thermal Conductivity

The exact level of thermal conductivity in a ceramic PCB depends on the manufacturing process, grain size, and material composition. While values may vary, industry experts generally provide the following ranges:

Aluminum Nitride (AlN):
- Commonly identified as >150 W/m·K, often around 170–180 W/m·K.
- Measured values range from 80–200 W/m·K at room temperature.
- Conductivity drops by roughly one-third when approaching 100°C.
Aluminum Oxide (Al₂O₃):
- Provides 18–36 W/m·K at room temperature.
- More economical but less effective for high-power applications.

Wire Pull Data

Bond Wire Strength
- Measured pull strength values ranged between 18–22 g, which is lower than the values achieved with the current substrate under the same contract manufacturer (CM) conditions.
- Despite this reduction, the majority of samples still exceeded the minimum requirement of 4g.
Failure Location
- All failures occurred at or near the substrate bond interface, suggesting that the substrate-to-wire bond is the critical point of weakness.

SLM 38964
SN KE048-030

		PF (g)	Mode
1	WB1	6	E
1	WB2	10	E
2	WB1	11	E
2	WB2	6	E
3	WB1	13	E
3	WB2	12	D
4	WB1	10	E
4	WB2	12	E
5	WB1	14	E
5	WB2	12	E
6	WB1	11	E
6	WB2	10	E
7	WB1	10	D
7	WB2	8	E
8	WB1	14	D
8	WB2	15	E
9	WB1	10	D
9	WB2	11	E
10	WB1	15	E
10	WB2	11	E

SLM 51157
SN KE039-033

		PF (g)	Mode
1	WB1	6	E
1	WB2	10	E
2	WB1	9	E
2	WB2	6	E
3	WB1	10	E
3	WB2	5	E
4	WB1	10	E
4	WB2	7	E
5	WB1	9	E
5	WB2	15	E
6	WB1	7	E
6	WB2	6	E
7	WB1	9	E
7	WB2	6	E
8	WB1	7	E
8	WB2	10	D
9	WB1	11	D
9	WB2	10	D
10	WB1	6	E
10	WB2	9	E

SLM 53839
SN KE040-005

		PF (g)	Mode
1	WB1	7	E
1	WB2	5	E
2	WB1	7	E
2	WB2	10	E
3	WB1	6	E
3	WB2	6	E
4	WB1	8	E
4	WB2	10	E
5	WB1	15	D
5	WB2	5	E
6	WB1	20	D
6	WB2	7	E
7	WB1	15	E
7	WB2	12	E
8	WB1	10	E
8	WB2	6	E
9	WB1	15	D
9	WB2	15	E
10	WB1	6	E
10	WB2	11	E

SLM 36250
SN KE039-030

		PF (g)	Mode
1	WB1	13	D
1	WB2	11	E
2	WB1	4	E
2	WB2	2	E
3	WB1	4	E
3	WB2	2	E
4	WB1	5	E
4	WB2	7	E
5	WB1	5	E
5	WB2	8	E
6	WB1	6	E
6	WB2	4	E
7	WB1	5	E
7	WB2	4	E
8	WB1	5	E
8	WB2	5	E
9	WB1	5	E
9	WB2	4	E
10	WB1	6	E
10	WB2	5	E

Total N 80
Subgroup size 1
Mean 8.6875
Standard Deviation(overall) 3.6547
Standard Deviation(within) 2.8616

X-Ray

Voids on 28511 and 35828 were within our ≤30% spec.
Mean voids on 29171 and 51764 were within spec, but some data points were well outside the 30% limit.
⁃ WOW = Worst of worst
⁃ BOB = Best of best.

WOW DIE BONDS

29171v2snZKE039-036

35.8%voids

28511v1snZKE038-034

13.24% Voids

35828v3snZKE048-032

23.61% Voids

51764v3snZKE040-008

41.12% Voids

BOB DIE BONDS

29171v2snZKE039-034

4.48% Voids

28511v1snZKE039-033

2.81% Voids

35828v3snZKE048-010

5.04% Voids

51764v3snZKE040-019

9.40% Voids

Distribution of Voids per Substrate PN

Normal

Summary & Next Steps

Substrate Handling & Packaging

Substrates received on blue tape are not acceptable for production.
Current suppliers ship substrates in a molded carrier, which holds multiple units securely.
Action: Recommend adopting molded carriers for future shipments. Reference photos/examples available.

Substrate Flatness

IBT substrates demonstrated superior flatness compared to current suppliers.
- Mean flatness <32 µm for 44×25 mm substrates.
- Mean flatness <10 µm for 21×25 mm substrates.
This performance is well within acceptable tolerance and supports assembly reliability.

Part Number & Serial Number Marking

Current markings do not meet specification:
- Part number should be centered on the substrate.
- Serial number should be indexed to the right (see reference drawings).
- Etching thickness should be reduced to maximize Cu/Au contact.
- Serial numbers must be laser etched/scribed only (not etched through metallization).
Recommendation: Match part marking style to current qualified supplier.

Metallization Concerns (Ni Undercut / Au Overhang)

All substrates exhibited evidence of Nickel undercut and Gold overhang; most severe in lot 51764.
Risks:
- Creates debris and loose edges, reducing confidence in measurement accuracy.
- Can negatively impact die bond voids and wire bond strength.
- Visually unacceptable per customer quality standards.
- Loose particles may contaminate SLM cavities in lamps or cause electrical shorts.
Action: Requires urgent process improvement to eliminate overhang/undercut.

Wire Bond Strength

Overall wire bond pull results were near or slightly above minimum specification:
- Lowest results observed on SLM 36250 (substrate 29171).
- CM-reported pull data slightly higher than customer-side results, but still below ideal levels.
All failures occurred at the substrate bond interface.
Potentially influenced by surface quality and cleanliness.
Action: Improve surface prep/cleanliness to support stronger bonds.

Die Bond Strength & Voiding

Die bond strength met requirements, with averages >7 kgf across samples.
Void performance mixed:
- 44×25 mm substrates showed excessive voids, often exceeding max specification.
- Lot 51764 performed worst in void testing.
- 21×25 mm substrates (28511, 29171) met void specifications.
Voids may be affected by surface condition and contamination.
Action: Review process to reduce voiding, especially in larger substrates.

Ceramic PCB Manufacturer

Key Products

As a leading ceramic PCB manufacturer, our core product line focuses on DPC (Direct Plated Copper) ceramic substrate circuit boards, which are widely used across the semiconductor and electronics industries. These high-performance boards provide excellent thermal management, reliability, and durability, making them essential for advanced applications such as:

High-Power LED Support Frames – Ensuring efficient heat dissipation and long operating life.
Microelectromechanical Systems (MEMS) – Supporting precise, miniaturized electronic devices.
Microwave & Wireless Communications – Delivering superior high-frequency performance.
Power Control Circuits – Enabling stable operation in high-power electronic systems.
Automotive Electronics – Providing reliability in harsh environments and demanding conditions.

In addition, we specialize in MiniLED glass backlight circuit boards, designed to meet the growing demand for next-generation display technology with high brightness, energy efficiency, and long-term stability.

DPC Ceramic Substrate Manufacturing Process

Ceramic Substrate Al2O3/AlN

Step 1: Laser Drilling

Step 2: Cu Sputter deposition

Step 3: Apply photoresist coating

Step 4: Circuit pattern exposure and development

Step 5: Electroplating Cu

Step 6: Remove photoresist

Step 7: Grinding and Polishing

Step 8: Ni/Au/Ag plating

Laser Drilling Capabilities

Our facilities are equipped with a wide range of advanced laser systems, including:

Laser Types: Picosecond, nanosecond, continuous wave (CW), pulsed, and fiber lasers
Wavelength Options: Infrared (IR), green, ultraviolet (UV), and CO₂ lasers

These systems enable high-precision processing for multiple applications, such as:

Micro-Drilling – Creating fine, accurate holes in substrates and materials
Defect Marking – Identifying and isolating defects for quality control
Surface Ablation – Controlled removal of thin material layers without damaging the substrate

TRUMPF Picosecond Laser from Germany

Picosecond laser drilling machine

Cu Sputter Deposition Capabilities

We operate multiple state-of-the-art Cu sputter deposition systems to meet diverse production and R&D needs:

Continuous PVD Vacuum Coating Lines – Two high-throughput systems from Von Ardenne (Germany) for consistent large-scale production.
MRC Semi-Automatic Three-Target Sputtering System (U.S.) – Includes plasma cleaning for superior surface preparation and adhesion.
1.6-Meter Rotating Target Vacuum Coating System – Supplied by Applied Materials (Germany), ideal for processing larger substrates.
Custom Three-Target Co-Sputtering System – Independently designed for PVD material experiments and advanced R&D applications.
Tunnel-Type PVD Coating Line (Taiwan) – Designed for small to medium batch production and rapid prototyping.

The bond strength between ceramics and metals is crucial.

These processes can handle all various composite ceramics and glass substrates.

Exposure and Development Capabilities

We provide advanced exposure and development processes to support high-precision ceramic and substrate manufacturing. Our equipment includes:

Fully Automatic Thick Film Photoresist Exposure System – LIGA
- Independently developed in-house for maximum control and customization.
- Capable of handling ultra-high and ultra-fine microstructure patterns beyond the limitations of conventional LDI (Laser Direct Imaging) equipment.
Karl Suss RC8 & RC33 Wafer-Level Photoresist Coating Machines
- Ensures uniform, high-quality photoresist application for demanding microelectronic applications.

Technical Capability

Line Width / Spacing: ≥ 10 μm
Patterning Advantage: LIGA enables production of complex, ultra-precise microstructures not achievable with standard photolithography systems.

LIGA can handle ultra-high and ultra-fine microstructure patterns that normal LDI equipment cannot achieve.

LIGA thick film photoresist exposure machine

Electroplating:

We design and produce high-power forward and reverse pulse electroplating power supplies in-house. With over 15 years of experience, our team has developed advanced processes including:

Wafer-level microstructure plating
Copper pillar bumping
Damascene copper electroplating
TSV and substrate through-hole plating
Blind vias
Carrier board mSAP and SAP processes

SAP multi-layer blind hole electroplating

Pulse waveform control

Self-developed repeatable precision micro/nano electroplating software

Grinding and Polishing:

Roughness control:

Flatness of bonding area ≤1.5μm
Surface roughness of bonding area ≤0.2μm

Precision grinding and polishing machines are essential specialized process equipment for the surface treatment of DPC ceramic substrates.

Ultra-precision grinding machine from Japan

Ni/Au/Ag Plating:

Capability:

Ni Nickel- conventional: 5μm ±2.5
Pd palladium – thin palladium (replacement): <0.025 μm
Thick palladium (reduction): <0.05-0.3 μm
Au gold – chemical gold: 0.025-0.08 μm
Semi-automatic catalysis: 0.1-0.3 μm
Electroplated gold (soft): 0.15-0.5 μm
Electroplated gold (hard): 0.1-1 μm
Ag silver – chemical silver: 0.25-1 μm
Electroplated silver: ≥1 μm

Equipment type:

Nickel-palladium-gold
Silver
Electroplated silver
Electroplated gold

Equipment Capability (Daily)

Laser Drilling: 50 square meters
Cu Sputtering: 1250 square meters
Exposure and Development: 100 square meters
Electroplating Cu: 80-100 square meters
Grinding and Polishing: 80-100 square meters
Probe test: 80 square meters
Surface Treatment: 100 square meters

IPQC Equipment

We collaborated with leading international research institutions to develop a proprietary AI quality control system for IP and DPC ceramic substrates. This system integrates automated optical inspection (AOI) for mass production, ensuring higher accuracy, faster inspection, and consistent quality for ceramic PCB manufacturing.

High-resolution substrate scanner

Surface (gold, silver, copper) scanner

AOI optical inspection system

Line pattern offset detection system

Flying probe testing

AOI line scanning, AI visual inspection

VEECO atomic force microscope (AFM)

German Fischer thick film detection machine to measure film thickness below 10 micrometers

ESPEC Shock test Equipment

X-ray plating inspection

Long-Term Research and Development

Cofan is committed to advancing ceramic PCB and semiconductor manufacturing technologies through continuous R&D. Key areas of focus include:

Ceramic–Metal Bonding
- Investigating the mechanism of ceramic and reactive metal active bonding forces.
- Optimizing vacuum deposition process parameters and methods for stronger adhesion and reliability.
Laser Applications in Ceramics
- Studying the effect of laser functions and power characteristics on the formation of conductive via holes in ceramic circuits.
Electroplating Technology
- Exploring the electroplating mechanism for THP (through-hole plated) conductive vias and high-aspect-ratio deep blind holes.
- Analyzing the impact of copper plating additives on deposition quality.
- Comparing pulse electroplating vs. direct current electroplating for via filling, blind hole metallization, and surface copper deposition.
Thick Film Processes
- Developing 100–400 µm thick film formation technologies, including exposure process optimization, equipment, materials, and process control.
High-Power Copper Circuits
- Defining deposition requirements and crystal morphology for conductive copper in high-power electronic circuits.
- Researching requirements and effects for functional module applications.
Surface Treatment for Advanced Packaging
- Establishing process requirements for semiconductor IC carrier boards and chip bonding/welding.
- Enhancing ceramic substrate surface treatment for chip packaging and eutectic soldering.
Eutectic Soldering Materials
- Advancing electrochemical deposition of eutectic solder alloys for reliable interconnects.
Smart Manufacturing Systems
- Continuous development and improvement of an intelligent manufacturing system to achieve higher levels of automation, precision, and efficiency.

Applications

Aluminum Nitride (AlN) is a high-performance ceramic material valued for its excellent thermal conductivity, electrical insulation, and mechanical strength. In power semiconductor components (PSC) and other high-power electronics, AlN is widely used to ensure efficient heat dissipation and reliable operation under demanding conditions.

Automotive

Aerospace

Medical

Heavy Machinery

Eletronics

LED Lighting

For extreme heat dissipation, please see our patented Multi-layer MCPCB.

Our unique and patented Super Pillar is proven to be 100x more effective at heat dissipation than conventional MCPCBs.

Aluminum-Nitride PCB(AIN PCB)