With the rapid development of science and technology, the electronic equipment industry has increasingly high requirements for circuit boards to achieve high performance and good heat dissipation in a limited volume. For this reason, the metal-based printed circuit board (MCPCB) came into being, and the electronic equipment industry has brought a technological revolution.
Reliable and advanced electronics manufacturers like FC are focusing on metal-core printed circuit boards (MCPCBs) to enhance the thermal performance of electronics. MCPCBs don’t use the standard FR4 PCBs and employ a metal core, most often aluminum or copper, to stabilize and emit heat at high-efficiency levels, conveying them the right choice for cooling and delivering essential mounting power in place.
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FC MCPCB Display
What is Metal Core PCB in electronics world?
A Metal Core Printed Circuit Board (MCPCB), also known as a Thermally Conductive Circuit Board or Metal Backed Circuit Board, is a type of PCB that uses a metal material as a heat sink on a substrate. The metal core is used as a heat sink, and the MCPCB improves heat dissipation at the board level by attaching the original printed circuit board to a different metal that is more thermally conductive. This new type of circuit board design effectively solves the heat dissipation problem caused by traditional circuit boards due to high-density integration (HDI), and greatly improves the stability and durability of electronic devices.
The use of this type of PCB is common in high-output LED lighting, automotive headlights, power substrates and numerous electronics where thermal dissipation is critical.
Why MCPCB is so important ?
Traditionally, printed circuit boards (PCBs), whose substrates are mainly made of glass fibers. However, with the advancement of technology and the miniaturization of electronic devices, the traditional PCB has been difficult to meet the needs of high heat and high power electronic devices. In this case, the emergence of MCPCB can be considered as a blessing in disguise.
The main advantage of MCPCB is its excellent thermal conductivity. Since metal has good thermal conductivity, MCPCB can quickly conduct the heat generated by electronic components to the metal substrate, and then dissipate the heat to the surrounding environment through the metal substrate, thus effectively reducing the temperature of the circuit board. This not only improves the stability and durability of electronic devices, but also provides the possibility of their operation in high-temperature environments.
In addition, MCPCBs offer more flexibility in design. Since the metal substrate can be bent, MCPCBs are able to adapt to various shapes of devices, which provides more options for designers of electronic devices. MCPCBs also have higher resistance to shock and vibration due to the protective effect of the metal substrate on the circuitry.
Structure of Metal Core PCB
An MCPCB is a sandwich structure that comprises multiple layers.
Core
The core of the MCPCB core can be made of either aluminum or copper. It depends on the requirements of the application.
Insulation/Isolation Layer
This refers to the layer of insulating or isolating material applied on top of the metal core. The purpose of this layer is to maintain the electrical isolation from the circuit and to increase heat spreading from components to the metal core further.
Copper Foil
These layers create the electronic highways (traces) between each component on the PCB.
Solder Mask
The solder mask is the top layer of the MCPCB, a protective layer to cover and insulate the copper traces to prevent short circuits during PCB assembly.
MCPCB Thermal Conductivity
The main factor determining the thermal conductivity of an MCPCB is the metal core and the dielectric layers’ materials.
Metal Core
Copper has a high thermal conductivity of around 380 -400 W/m.k and that of aluminum is 200-250 W/m.k.
Dielectric Material
MCPCBs in the dielectric material add thermal conductivity means, and also play a very good electrical insulating property. The use of thermally conductive epoxy resins and prepreg materials, with added fillers, helps enhance the overall thermal performance of the PCB.
Dielectric Material of MCPCB
The dielectric material employed in MCPCBs is essential to provide both electrical insulation as well as heat dissipation. The most common dielectric materials are.
Thermally Conductive Epoxy Resins
These resins are filled with thermally conductive particles (such as ceramics or metals) to achieve improved thermal conductivity as well as insulating electrically.
Prepreg
Prepreg (pre-impregnated) materials are fiberglass braid that have been run through resin. They are used between the layers of the PCB to bond them together and can be selected based on dielectric properties as well.
The dielectric material is chosen based on application requirements such as thermal conductivity, electrical insulation properties, and mechanical strength.
Manufacturing Process of MCPCB
There are many important stages in the manufacturing of MCPCBs.
Material Selection
It starts with choosing the right materials. They have a metal core, either of aluminum (90% of normal radiator applications) or brass (10% of normal radiator applications) and which are both quite light and high thermal conductive metals. Copper and steel are possible alternative materials, with their different insulating abilities helping to improve the mechanical strength of the tiles. Which type of metal core material to choose depends on the application’s thermal and mechanical requirements.
Preparation of the Metal Core
The preparation of the metal core includes pre-treating the metal surface to prepare it for the paint or powder. This is critical since the surface treatment helps to get good adhesion of the dielectric layer and proper electrical performance of the board.
Dielectric Layer: To be used in applications
The dielectric layer is another important factor of modern MCPCBs because it functions as an insulator between the metal core and the copper circuit layer. This layer is generally composed of a thermally conductive material that does not conduct electricity. The dielectric is applied to the metal core using a lamination process, which applies heat and pressure persuading the materials to bond uniformly throughout.
Copper Cladding
Next, clad the structure with a thin copper foil after the dielectric layer is applied. This copper layer is used to form the conductive pathways that will allow the transport of electricity throughout the PCB. The thickness is not always the same, which changes depending on what a specific product requires in current-carrying requirements. Most circuits come in thicknesses of, 1 oz/ft², 2oz/ft², and 4 oz/ft². The technique for transforming the copper film is to apply heat and pressure that cause the copper foil and dielectric layer to bond together firmly.
Imaging and Etching
Manufacturers also thoroughly clean the surface to remove any contaminants. After that, they applied a photoresist layer on the copper surface to derive the desired shape from the copper sheet. They next expose the photoresist to UV light by projecting the light through a mask that carries the proper circuit diagram. The hardened texture is seen when areas are left exposed, whereas the unexposed areas are still soft and can now be washed away. This process will result in a copper pattern under the hardened photoresist.
The board is then chemically etched to remove the unneeded copper. Hey Dancing Plague; Copper that is not part of the circuit is then dissolved from the board using chemical solutions – typically ferric chloride, or ammonium persulfate. After completing the etching, the manufacturer burns out the remaining photoresist layer to expose the copper circuit on the PCB board.
Drilling and Plating
After circuit patterning finishes, the board needs to be drilled for component installation and interlayer connections. Fastener and riveting machines, Precision drilling is performed to create a hole in a specified location. These holes are now plated after drilling. The most typical example is electro-copper plating, which results in a thin layer of copper deposited inside the holes, thus guaranteeing electrical continuity among different layers of the board.
Solder mask and silk screen
A protective solder mask is required for the board after plating. During the soldering of components, this mask keeps solder bridges between conductors that are close to one another. The pads and vias are the only areas of the board where the manufacturer does not apply the solder mask. These regions become mask-free and prepared for soldering after being exposed to UV light and going through further development procedures. The solder mask application is followed by a silkscreen layer. Important information is provided by the silkscreen layer, which often includes logos, component labels, and other markings. In order to assure endurance, the ink must first be cured after being applied to the board using a screen-printing technique.
Surface Finishing
Applying a surface treatment to the exposed copper pads is the last step before assembling the components. Reliable soldering is ensured by the surface treatment, which shields the copper from oxidation. HASL (Hot Air Solder Leveling), ENIG (Electroless Nickel Immersion Gold), and OSP (Organic Solderability Preservative) are common finishes. Many variables, including application, soldering technique, and budget, influence the finish selection.
Testing and Quality Control
Rigorous testing and quality control are the last stages of MCPCB manufacture. To make sure there are no shorts or open circuits and that all circuits are constructed appropriately, each board is electrically tested. Inspections, both visual and automated optical (AOI), look for flaws such as solder bridges and other misalignments in components.
Types of Metal Core Printed Circuit Boards (MCPCB)
There are a variety of types of Metal core PCB, and each type of MCPCB has unique features and benefits. Let us guide you to a quick understanding of these types.
Double Layer MCPCB
Double-layer MCPCBs are different from conventional single-layer MCPCBs as the latter are made from two parallel copper layers, a metal base, and one or several dielectric layers. In addition, it is also possible to produce even more complex circuits in a single board as well as more components per unit area with the use of double-layer MCPCB.
Single layer MCPCB
Single-layer MCPCB has a single copper layer above the aluminum or copper core, with the lower part only containing a metallic core surrounded by insulating material. An example of is a single-layer MCPCB – this design has one layer of cooper, one dielectric layer, and one metal base.
COB MCPCB
COB Metal Core PCB stands for Chip-On-Board of Metal Core PCBs which is of a particular type of MCPCB, which is advantageous in the thermoelectric splitting. This is as follows, by adopting the use of MCPCB into COB, the so-called ‘die’ can physically connect with the traces on the circuit board through the wire bonding method, as well as touch the metal core, which is a heat sinking feature. This material has an RMC of more than 200 W/m of thermal conductivity for COB MC PCB.
MCPCBs are printed circuit boards that incorporate a metal core, usually copper or aluminum, to provide increased thermal conductivity. Thermal conductivity is an important characteristic of high power components. As a result of this, they are suitable for applications that include; power substrates, LED lighting, and automobile electronics.
The circuits of MCPCBs are composed of a solder mask, cooper foil, dielectric layer, and metal core, so that the electrical insulation and temperature management are good condition. A successful procedure is implemented during the production process to ensure that reliable and excellent performance is attained.
Single and double MCPCB, multilayer and COB are versatile in their designs for usage and provide solutions for distinct requirements.
Overall, MCPCBs are a reliable and efficient solution for high-power scenarios, which becomes instrumental in modern electronics due to increased demands on thermal control.