sales@ipcb.com
1. What is an aluminum substrate PCB?
PCB also known as a printed circuit board. Aluminum substrate is a type of PCB. Aluminum substrate is a metal-based copper-clad laminate
with excellent heat dissipation. Generally, a single-sided board consists of three layers: a circuit layer (copper foil), an insulating layer, and a metal base.
High-end designs can also be designed as double-sided boards, with a circuit layer, insulating layer, aluminum base, insulating layer, and circuit layer. In rare applications,
multi-layer boards are constructed by laminating a standard multi-layer board with an insulating layer and an aluminum base.
Single-sided aluminum PCBs: These consist of a single conductive pattern layer, an insulating material, and an aluminum plate (substrate).
Double-sided aluminum PCBs: These consist of two conductive pattern layers, an insulating material, and an aluminum plate (substrate) laminated together.
Multi-layer aluminum PCBs: These are printed circuit boards made by alternately laminating and bonding three or more conductive pattern layers, an insulating material,
and an aluminum plate (substrate).
2. Working Principle of Aluminum Substrates
Power devices are surface-mounted on the circuit layer. Heat generated by the devices during operation is rapidly transferred through the insulating layer to the metal substrate,
which then dissipates the heat away from the devices.
Compared to traditional FR-4 substrates, aluminum substrates minimize thermal resistance, resulting in excellent thermal conductivity. Compared to thick-film ceramic substrates,
they also offer superior mechanical properties.
Additionally, aluminum substrates offer the following unique advantages:
RoHS compliant;
Easier to use with SMT processes;
Effectively manage heat dissipation within the circuit design, thereby lowering module operating temperatures, extending service life, and improving power density and reliability.
Reducing the need for heat sinks and other hardware (including thermal interface materials) reduces product size and reduces hardware and assembly costs.
They optimize the integration of power and control circuits.
Replacing fragile ceramic substrates for improved mechanical durability.
3. Aluminum Substrate Composition
Circuit Layer
The circuit layer (typically made of electrolytic copper foil) is etched to form a printed circuit for device assembly and connection. Compared to traditional FR-4,
with the same thickness and line width, aluminum substrates can carry higher currents.
Insulation Layer
The insulation layer is the core technology of aluminum substrates, primarily providing bonding, insulation, and thermal conductivity.
The aluminum substrate insulation layer is the largest thermal barrier in the power module structure. The better the thermal conductivity of the insulation layer,
the more it facilitates the dissipation of heat generated during device operation, thereby reducing the device's operating temperature, thereby increasing the module's power load,
reducing size, extending life, and improving power output.
Metal Base
The choice of metal for an insulated metal substrate depends on a comprehensive consideration of factors such as the substrate's thermal expansion coefficient,
thermal conductivity, strength, hardness, weight, surface condition, and cost.
4. Aluminum Substrate Performance
Heat Dissipation
Currently, many double-sided and multi-layer boards have high density and high power consumption, making it difficult to dissipate heat.
Conventional printed circuit board substrates, such as FR4 and CEM3, are poor conductors of heat. The insulation between layers prevents heat dissipation.
This can lead to localized heating in electronic devices, causing component failure due to overheating. Aluminum substrates can solve this heat dissipation problem.
Thermal Expansion
Thermal expansion and contraction are common properties of matter, but different materials have different thermal expansion coefficients. Aluminum-based printed circuit boards
effectively address heat dissipation, mitigating the thermal expansion and contraction of components on the printed circuit board,
thereby improving the durability and reliability of the entire device and electronic equipment. This is particularly effective in addressing thermal expansion and
contraction issues associated with SMT (surface mount technology) assembly.
Dimensional Stability
Aluminum-based printed circuit boards are significantly more dimensionally stable than those made from insulating materials. When heated from 30°C to 140-150°C,
the dimensional change of aluminum-based printed circuit boards and aluminum sandwich panels is 2.5-3.0%.
5. PCB Aluminum Substrate Applications
Audio Equipment: Input and Output Amplifiers, Balanced Amplifiers, Audio Amplifiers, Preamplifiers, Power Amplifiers, etc.
Power Supply Equipment: Switching Regulators, DC/AC Converters, SW Regulators, etc.
Communications Electronic Equipment: High-Frequency Amplifiers, Filters, Transmitter Circuits, etc.
Office Automation Equipment: Motor Drivers, etc.
Automotive: Electronic Regulators, Ignition Devices, Power Controllers.
Computers: CPU Boards, Floppy Disk Drives, Power Supplies, etc.
Power Modules: Inverters, Solid-State Relays, Rectifier Bridges, etc.
Lighting Fixtures: With the promotion of energy-saving lamps, aluminum substrates for LED lamps are also beginning to be widely used.