What is Metal Core PCB?
Metal Core Printed Circuit Board (MCPCB) is a special type of PCB that features an additional metal substrate with high thermal conductivity, built on top of the traditional PCB structure. This design effectively enhances the heat dissipation capacity of the circuit board, which helps lower the operating temperature of electronic components, thereby improving the stability and reliability of the system.
Major Metal Substrates Used in MCPCB
Aluminum MCPCB
Aluminum is one of the most commonly used MCPCB substrates due to its low cost, lightweight properties, and good thermal conductivity, Aluminum PCBs have a high thermal conductivity of about 200 W/MK,effectively enhancing product heat dissipation and reliability.which can satisfy most applications that require good heat dissipation. In addition, aluminum is cheaper than copper, softer than iron, and easier to process and form. Therefore, its material and manufacturing costs are relatively moderate. Aluminum MCPCBs are widely used and can be found in LED, power supply, communication electronic, automobile, power module, audio, and other equipment.
According to the material of the aluminum substrate, the most common are aluminum alloy 5052 and 6061. 5052 is aluminum-magnesium alloy, and 6061 is aluminum-magnesium-silicon alloy. In comparison, 6061 has better overall function but is also more expensive.
Copper MCPCB
Copper MCPCB has the best mechanical strength, durability, and thermal conductivity (twice that of aluminum PCB), so they are widely used in high-power rectifiers, overload relays, solar power converters, renewable energy equipment, railroad systems, power modules and high-frequency communication devices， and monitor power cords, etc. However copper MCPCB are also the most expensive of the three, so if your application doesn’t require much in the way of thermal conductivity, etc, then consider aluminum MCPCB as a more economical option.
Iron MCPCB
Although iron has lower thermal conductivity compared to aluminum and copper, it offers higher mechanical strength and advantages in applications requiring electromagnetic shielding. For example, iron-based MCPCBs provide additional structural strength and electromagnetic shielding in industrial control equipment and power electronics.
Iron PCBs offer improved stability and electromagnetic shielding along with a low coefficient of thermal expansion (1.17×10-3) making them particularly well suited for ceramic lamps. However their thermal conductivity coefficient falls short compared to other MCPCBs（Copper MCPCB or Aluminum MCPCB ） and the hardness of iron presents challenges in the manufacturing process. Therefore, although the iron itself is not costly, the overall cost can be higher due to the complexity of manufacturing.
Common Metal Core Printed Circuit Boards
The structure of MCPCB is very similar to that of FR 4 PCB. Metal core PCB has a stack consisting of a core, a dielectric layer or insulation layer, and a copper layer or circuit layer. It mainly has a bare core made of metals such as aluminum, aluminum alloy, or copper. In addition, aluminum PCBs also come with a layer of aluminum base film. Most aluminum PCBs consist of 1-2 layers and have a relatively simple structure. However, some high-power applications may require a more complex structure. The thickness of the metal core can vary according to different requirements, and usually the thickness of the metal core ranges from 1 mm to 1.6 mm.and QFPCB can produce aluminum PCBs with up to 6 layers (metal core + FR4 mixed pressing can also be produced).
1. Copper Foil Layer: The layer of copper foil, on an aluminum circuit board is quite thick typically ranging from 1 to 3 ounces, is positioned at the top of the board. This thicker copper layer offers increased capacity for carrying current.
2. Dielectric layer: Also known as the thermal insulation layer, this layer is the core of the aluminum printed circuit board, located in the middle of the copper layer and the aluminum base layer, with thermal conductivity, insulation, and bonding. It is the largest insulation layer in the power module structure. Depending on the application we can choose different material as dielectric layer.
3. Aluminum base layer: The aluminum base layer consists of an aluminum substrate, typically white. It offers excellent thermal conductivity, efficiently dispersing heat to surrounding areas to keep electronic devices within safe temperature limit. Moreover, it provide mechanical support for the aluminum printed circuit board.
4. Aluminum base membrane layer: The layer of aluminum provide protection by safeguarding the aluminum surface from scratch and undesired etching. Usually the thickness of the aluminum base film layer is 76.2 um to 152.4um which is the core technology of aluminum-based copper clad laminate, and has obtained UL certification.
Single Layer Metal Core PCB
A single-layer metal core PCB is the most commonly used stacking type, and it is the easiest to manufacture with the lowest cost. It consists of a wiring layer, with the traces directly etched onto the copper layer of the metal core laminate. The metal core PCB is isolated from the signal layer with the help of a thermal insulation material layer. Heat is transferred from the components to the trace layer, then through the intermediate insulation thermal conduction layer, and finally to the metal core PCB.
Single Side Surface Mount Double Layer Metal Core PCB
A single-sided mounted, double-sided routed metal core PCB has two trace layers and insulation layers. Heat is transferred from the components to the first trace layer, then through the first insulation layer, to the second trace layer, through the second insulation layer, and finally to the aluminum layer. It requires the use of blind vias as signal or thermal pathways, so more precise manufacturing processes are needed. The double-sided routed metal core PCB is suitable for high-power applications that require more complex circuit designs, such as power management systems.
Thermoelectric Separation Metal Core PCB
Thermoelectric separation stackup is very similar to a single-layer metal core PCB, except the core is made of copper and the stackup is such that the core touches the body of the component without touching the pads of the component. The pads of the component are insulated by the dielectric material which ensures proper electric isolation with the highest grade of thermal efficiency.
Such Metal Core PCBs are extensively used in high-power LEDs. Thermoelectric separation PCBs are very expensive to fabricate, hence they are not used in simple LED solutions
Double-sided mounting double-sided Metal Core PCB
Sometimes, a metal-based PCB with components arranged on a single side cannot meet the requirements, and the metal core PCB can be designed for double-sided mounting. In this stacked design, the trace layers on both the top and bottom must pass through the metal core layer, as the metal core PCB is also a good conductor. Therefore, vias must be insulated, for example, by filling the vias with insulating resin around them. The heat generated by the components is transferred from the components to the trace layers, then through the insulation layers, and finally to the middle metal core layer. From a manufacturing perspective, this also increases the difficulty and cost of production, as it involves complex processes such as drilling and thermal bonding.
Multilayer Metal Core PCB
Like double-layer metal core PCBs, multilayer ones have more copper and dielectric layers in between the surface copper and metal core. It is not recommended to go beyond 4 layers for multilayer metal core PCBs (most of the metal core PCB manufacturers can only build up to 4 layers) as the thermal management of the PCBs degrades significantly due to increased spacing and dielectric insulation between the components and the metal core. Since more than 2 layers are used, the use of blind and buried vias can also be implemented on multilayer metal core PCBs.
High Frequency Aluminum PCB
The dielectric layer consists of polyimide or polyolefin resin glass fiber prepreg so that it can maintain good electrical properties and stability under high-frequency conditions, so it is suitable for high-frequency communication equipment and microwave equipment. Its cost varies according to specific materials and design requirements. But generally speaking is higher than the high thermal conductivity of aluminum PCB.
F4BM and F4BME series aluminum/copper substrates: This series of products can provide aluminum-lined or copper-lined materials, that is, one side of the dielectric layer is covered with copper foil, and the other side of the dielectric layer is covered with copper or aluminum, which plays a shielding or heat dissipation role.The models are F4BM220-AL, F4BME265-AL, F4BM220-CU, and F4BME300-CU.
Copper or aluminum base thickness: 0.48mm, 0.98mm, 1.48mm, etc. Other thicknesses can be customized.
Applications of MCPCB
Due to its excellent thermal conductivity, mechanical strength, and electromagnetic shielding properties, MCPCB is widely used in multiple high-power and high-heat dissipation applications.
LED Lighting
High-power LEDs generate significant heat, and inadequate heat dissipation can lead to light decay and reduced lifespan. MCPCB, with its efficient heat dissipation capabilities, is widely used in street lights, automotive lights, stage lighting, and other LED lighting systems.
Power Modules
MCPCB is crucial in high-power DC-DC converters and power management systems, helping maintain stable operating temperatures and preventing overheating-induced performance degradation or damage.
Automotive Electronics
Modern automotive electronics, such as EV charging control systems, in-vehicle LED lighting, and battery management systems, require excellent thermal management. MCPCB’s high thermal conductivity and vibration resistance make it a key material in automotive electronics.
High-Frequency Communication Devices
5G base stations, RF modules, and microwave communication equipment require PCBs with not only good heat dissipation but also low signal loss. Copper-based MCPCB is widely used in these fields due to its high thermal conductivity and low resistance.
Industrial Automation Equipment
Inverters, controllers, and other industrial electronics generate significant heat during prolonged operation. MCPCB’s superior heat dissipation capabilities improve system reliability and extend equipment lifespan.