Aluminum Substrate

• Material composition of aluminum substrate

1. Core materials

Aluminum (AL) or aluminum alloy (AL 5052, AL 6061):

Thermal conductivity is good (~200 W/M·K), but lower than copper.

The coefficient of thermal expansion (CTE) is high (~23×10⁻⁶/K), so the matching chip material needs to be optimized.

Lightweight (density 2.7 G/CM³, only 30% of copper), suitable for lightweight requirements.

2. Insulation layer material

Epoxy resin (FR-4): low cost, but poor thermal conductivity (~ 0.3 W/M · K).

High thermal insulation adhesive (such as ceramic filled epoxy resin): the thermal conductivity is increased to 1-5 W/M·K.

High thermal insulation film (such as PI or ceramic coating): for higher heat dissipation requirements.

3. Copper circuit layer

The surface is covered with copper (usually 18-105ΜM) for conductive wiring, which is formed by etching.

4. Surface treatment materials

Chemical nickel/gold plating (ENIG): improves oxidation resistance and welding properties.

OSP (organic solderability protection film): low cost oxidation prevention scheme.

• Manufacturing process of aluminum substrate

High thermal conductivity aluminum substrate (ceramic composite aluminum substrate)

Aluminum nitride (ALN) or aluminum oxide (AL₂O₃) is used as the insulating layer, and the thermal conductivity is increased to 10-30 W/M·K.

Thermal adhesive or brazing process is used to enhance the bonding strength between aluminum and insulation layer. It is used in high power LED, automotive electronics, etc.

• Material performance advantages of aluminum substrate

| function                  | Aluminum substrate (MCPCB) | Copper substrate (DBC) | FR-4 PCB

| Thermal conductivity (W/M·K) | 1-30 (depending on the insulation layer) | 24-200          | 0.3-5

| Thermal expansion coefficient (x10⁻⁶/K) | 23                  | 6-8             | 14-18

| Weight (G/CM³) | 2.7 (lightweight)         | 8.9 (heavier) | 1.8-2.0

| prime cost                  | Low (1/3 of copper) | High             | lowest

| mechanical strength              | secondary                | tall             | low

core advantage:

Low cost (aluminum is much cheaper than copper and suitable for large-scale applications)

Lightweight (70% lighter than copper substrate, suitable for portable devices)

Good heat dissipation (better than FR-4, suitable for medium and low power requirements)

Easy to process (mechanical processing performance is better than copper)

• Industry application and technical index advantages

1. LED lighting (high power LED, COB packaging)

Efficient heat dissipation, extend LED life (reduce light decay), lightweight, suitable for lamp design, suitable for LED car lights, outdoor display screens, plant growth lamps.

2. Power modules (AC/DC converters, inverters)

The heat dissipation is better than FR-4, the power conversion efficiency is improved, the cost is low, suitable for consumer electronics, mobile phone fast charging, photovoltaic inverter, industrial power supply.

3. Automotive electronics (headlights, BMS, motor control)

Vibration resistant, impact resistant, suitable for harsh environment, lightweight helps to reduce the weight of new energy vehicles, suitable for electric vehicle battery management system (BMS), LED headlights.

Consumer electronics (TV backlighting, laptop cooling)

Thin design, suitable for compact space, low cost, suitable for mass production, suitable for MINI-LED backlight, game cooling substrate.

• Future development trend

1. Higher thermal insulation materials

Develop nanoceramic filled insulation layer (such as ALN/graphene composite) to improve the thermal conductivity to more than 50 W/M·K.

2. Lower CTE aluminum substrate

The CTE is reduced to 10×10⁻⁶/K or less by using aluminum-silicon carbide (AL-SIC) composite material, which is suitable for high-power chips.

3. Flexible aluminum substrate

Combined with flexible circuit technology, it is used in wearable devices and curved LED screens.

4. Green manufacturing process

Promote cyanide-free electroplating, laser etching and other environmental protection processes to reduce pollution.

5. Optimization of high-frequency applications for 5G/6G

Develop low dielectric loss aluminum substrate for millimeter wave RF devices.

Aluminum substrates, with their low cost, lightweight design, and excellent heat dissipation, have become the mainstream choice for LED lighting, power modules, and automotive electronics. In the future, as high-thermal-conductivity composite materials, low-CTE optimization, and flexible electronics advance, aluminum substrates will further expand into areas such as new energy vehicles, MINI/MICRO LED, and 5G communications, becoming the king of cost-effectiveness for medium and low-power cooling solutions.