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Comparing Different Types of Printed Circuit Board Materials
Printed circuit boards (PCBs) are essential elements in any kind of electronic device, therefore, it’s essential to choose the right materials when manufacturing them. Yes, the quality of a PCB depends largely upon the quality of the materials used to manufacture it, making them crucial.
So, if you’re looking to manufacture well-performing PCBs, you should know the different types of PCB materials that bring them to life. That’s because the choice of PCB material significantly impacts the performance, durability, and cost of electronic systems.
In this blog, we're going to guide you through a comprehensive comparison of the types of PCB materials, their properties, and ideal applications. It’ll help you to know them all and make the right material selection for your next big project! But, before digging deeper, let’s get started from the basics first!
What are Printed Circuit Board Materials?
Printed circuit board materials tend to be the base substrate utilized to manufacture a PCB. They serve as the foundational material in printed circuit board fabrication, allowing the flow of current across circuits. The circuit has a wide range of semiconductor parts and active and passive components.
When the schematic is decided on the technical requirements, we achieve the functional behavior, circuit flow, and connectivity amongst multiple electronic components by placing these parts and creating a PCB with printed circuit board substrate materials.
A printed circuit board is manufactured using raw materials like epoxy, fiberglass, resin, and copper dielectric. These are the core elements of any PCB when they are being manufactured.
Different Types of Printed Circuit Board Materials
The following are the different types of PCB materials you should know before starting PCB manufacturing!
CCL (Copper-Clad Laminate)
Copper-Clad Laminate (CCL) tends to be the foundational material in PCB production. It is made of a dielectric substrate that is laminated with a thin layer of copper on either one or both sides. Copper laminate offers excellent conductivity for all the board traces, ensuring signals flow efficiently throughout the etched traces.
Determining the copper foil thickness depends on certain operational requirements of the application, It is generally measured in ounces per square foot (Oz/ft²). Businesses use thicker copper layers in high-power applications to ensure enhanced current-carrying competencies and heat dissipation.
PCB Core(Substrate)
The PCB core is a kind of CCL that is used in multilayer PCB production, serving as the backbone. It provides structural integrity and electrical insulation between multiple circuit layers. FR4 is the most commonly used PCB substrate material, a fiberglass-reinforced epoxy laminate well-known for its extraordinary thermal and mechanical properties.
Some additional materials, such as PTFE, polyimide, and Rogers laminates are used for building high-temperature and high-frequency applications.
Solder Masking Layer
The solder mask layer is a PCB material that has a significant role in protecting the circuit board. It is a protective layer that covers all the conductive copper traces on the board, barring certain areas where component leads and pads are exposed for soldering.
This very layer prevents oxidation, short circuits, and accidental bridging during the soldering procedure. In general, it’s green, but other colors like blue, black, red, and white are also used for the same.
Copper Layer
Copper is the primary conductive material in the printed circuit boards. It allows the creation of traces that carry electrical signals and power across various components. The thickness of the copper layer largely influences the current-carrying capacity and is selected based on the application's power needs.
As far as the standard copper thickness values are concerned, they range from 1 oz/ft² to 3 oz/ft², with optimal values used for power electronics.
Prepreg
Prepreg materials are made up of fiberglass. It is used as glue to stick all the multiple layers together during manufacturing.
Prepreg (pre-impregnated composite fibers) are made of fiberglass infused with resin that remains semi-cured. During printed circuit board manufacturing, it acts as an adhesive layer between multiple PCB cores or substrates.
During the lamination, when heat and pressure are applied, the resin in the prepreg fully cures, bonding the layers together with optimal security.
Surface Treatments
Surface treatments are protective metal coatings. They are applied to the exposed copper pads of PCBs, aiming to prevent oxidation and contamination. They enhance solderability and foster reliable connections in PCB assembly.
Mentioned below are the most common surface finishes you should know about:
ENIG (Electroless Nickel Immersion Gold)
ENIG tends to be a two-layer surface finish wherein a layer of nickel is chemically deposited onto the copper pads, followed by a thin layer of immersion gold on the copper pads. This finish provides:
HASL (Hot Air Solder Leveling)
HASL is one of the most widely used and cost-effective surface finishes. It involves:
ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold)
ENEPIG is made up of a multi-layer surface including nickel, palladium, and gold. While the Nickel provides the primary barrier and mechanical strength, the Palladium acts as a diffusion barrier, preventing gold from migrating into the nickel. The Gold ensures excellent oxidation resistance and solderability. ENEPIG provides:
Immersion Silver
Immersion Silver is a surface finish that is applied to PCBs by immersing the board into a solution that contains silver ions. The very process tends to deposit a thin but highly conductive silver layer onto exposed copper pads. Immersion Silver provides excellent electrical conductivity, high-end solderability, and moderate oxidation resistance. This makes it a suitable choice for high-frequency and high-speed applications.
Hard Gold
Hard Gold is made of a thick layer of gold plated over a layer of nickel for high-level durability. It is primarily used in edge connectors, contact fingers, and switch components where frequent mechanical contact takes place.
This surface finish happens to be highly durable, resistant to wear and ensures low contact resistance over time. It makes it an ideal choice for applications in need of frequent insertions and removals.
Conclusion: Choosing the Right Material for Your Application
When choosing PCB materials, factor in different scenarios like operating temperature, mechanical strength, signal frequency, and cost. Besides, having a detailed understanding of the differences between PCB materials is essential. Be it flexibility, durability, or high-frequency assistance, the right PCB material selection will make the difference needed.
If you need to, consider collaborating with the right PCB manufacturing company and bring your concept to reality. The right PCB manufacturer will help you ensure the best material is chosen for your specific needs.