Along with the continuous attempt to design and produce electronic devices that are smaller and faster, come also the issues that may arise due to increasing power densities. The dense circuit may lead to thermal concerns when heat is not effectively dissipated. Component heating can lead to premature failures and device malfunction.

The most common type of PCB that we know of is an FR4 PCB due to its affordability and performance in countless applications. However, another type called aluminum-based PCB has gained attention for achieving a reliable circuit board that can meet the requirements of fast and high-power electronics. As FR4 PCB is not the best and most practical option for high-power applications, an aluminum circuit board is the best alternative for high-current and voltage devices.

In this article, we will elaborate on the importance of Aluminum PCBs in the electronics field.

What is an Aluminum PCB?

An Aluminum PCB is a popular type of metal-core PCB that can handle high temperatures and has excellent manufacturability. It is most used in high-power applications due to its good thermal dissipation properties. Aluminum printed circuit board is a very good alternative to FR4 PCB for this purpose. Its ability to cool the device with its heat transfer efficiency helps extend the lifetime of electronic products and components. Other applications that make use of Aluminum printed circuit boards also include the following:

1. Power Applications. Power LEDs (Light-emitting Diodes), power transistors, and inverters for many energy storage devices make use of Aluminum circuit boards.
2. Medical Devices. Medical devices need to maintaingood performance while in use. Aluminum-based circuit boards serve as electronic boards for important healthcare devices such as imaging systems and diagnostics equipment.
3. Telecommunications. Managing heat in telecommunications devices is important to ensure signal integrity; thus, an aluminum circuit board is a useful technology for maintaining consistent device function.
4. Automotive Electronics. Aluminum-based boards are also vastly used in automotive electronics. Some of the vital electronics inside modern vehicles have aluminum circuit boards, such as their power modules, lighting systems, and vehicle charging systems.

An aluminum-based PCB can be sectioned into three major parts the conductive layer where the circuitry sits, the dielectric layer which is typically characterized by good thermal conductivity and dielectric properties, and lastly, the base layer which is the aluminum base. The metal base has very good thermal conductivity that allows effective cooling of the device. The conductive layer is made of copper with thicknesses that depend on the desired performance.

How are Aluminum PCBs Fabricated?

To further deepen our understanding of Aluminum PCBs, we explain the overview of its different fabrication steps.

1. Lamination: In the lamination process, the copper foil is bonded together with the Aluminum substrate at a specified temperature and pressure.
2. Imaging and Etching: Photoresist is applied on the copper film based on a defined circuit pattern.
3. Expose and Develop: The photosensitive resist is exposed to UV light through masking to reveal the intended pattern.
4. Copper Etching: The exposed copper is removed to fully form the circuit.
5. Drilling: Holes are drilled to form the conductive vias. This can be through mechanical means or using laser drills for micro-vias.
6. Solder Mask and Silkscreen: The PCB is coated with a solder mask as a protective layer. Silkscreen is used to put labels and references on the Aluminum-based PCB.
7. Surface Finish: The pads have a protective surface finish to shield against oxidation. Many options are available such as electroless nickel gold, immersion tin and so on.

What are the Top Benefits of Aluminum PCBs in Your Project?

The vast utilization of aluminum PCBs denotes its great importance in modern electronics. Below are its top benefits, which are also why aluminum-based PCB is the best choice for your project. The Aluminum PCB manufacturing techniques have changed with the passing days and PCB manufacturers should

• Excellent thermal performance. Aluminum is a relatively affordable metal with high thermal conductivity. This is because of the free electrons on its atomic structure that carry thermal energy. These attributes make aluminum an excellent choice for applications where efficient heat transfer is necessary. Conduction of heat is important in high-power applications to prevent failures. As the circuit board base, aluminum helps keep the heat away from critical components of the PCB.
• Improved Durability. As a metal, aluminum has good mechanical strength, which enables optimum conditions even with exposure to physical stresses. Adding to its durability is the ability of aluminum circuit boards to form a protective passivation layer in the form of aluminum oxide. This layer protects the aluminum surface from corrosion, which helps prolong the life of the device.
• Good Reliability. Because of the aluminum circuit board’s good thermal conductivity, it has also excellent reliability performance even at high temperatures. Aside from its favorable thermal properties, it is also able to resist physical deformation due to mechanical stresses. Metal core PCBs undergo reliability tests to determine their endurance against temperature and humidity for prolonged periods. If not using an aluminum or metal base for high-power applications, overheating can occur if the heat gets concentrated on specific locations of the printed circuit board.
• Lightweight. Aluminum is also considerably a lightweight material due to its tightly packed atomic structure and overall low density. This is a desired characteristic, especially for electronic devices that need to be portable, compact, and user-friendly. Despite being a lightweight metal, it has good mechanical strength which makes it a suitable option for automotive, industrial, and commercial applications. Its weight is a significant factor in why aluminum is very prominent for electronic devices.
• Ease of Processing. Aluminum-printed circuit boards are also very convenient to machines and processes. Unlike other metals, aluminum is comparatively softer which is why it is easier to drill, form and shape. The lamination process is easy to carry out when bonding the dielectric layer and the aluminium substrate. The simplicity of its machining processes reduces the cost of producing aluminum-based PCBs.