What is Copper Clad Laminate (CCL)? A Complete Guide

Introduction

Your printed circuit board is made of copper-clad laminate (CCL). The origin of almost all modern electronic devices begins with this PCB laminate. The kind of CCL material that you use will have a direct effect on the performance of your board. In this guide, you will learn about the various kinds of laminate and what makes a good laminate.

What Is Copper Clad Laminate (CCL)?

Almost all electronics are made of copper clad laminate (CCL). This PCB laminate is a combination of copper foil and substrate, which mechanically supports and constitutes the basis of the pathways of your circuit. You would use copper-clad laminate in smartphones and industrial control systems. Whether it is standard FR-4 laminate or a high-frequency laminate, the selection of a suitable type is what will make you successful in your project.

Types of Copper Clad Laminates

Copper clad laminate can be categorized in many important ways, and this assists in choosing the appropriate PCB laminate for your project. The primary types are based on the rigidity, core material, resin, and performance characteristics of the board. Knowing these differences guarantees you select the most suitable CCL material to use in your application.

Mechanical Rigidity

The initial choice usually relates to the physical flexibility of the board. The decision depends on how and where your final product will be used. You will have to determine whether one has to fit a complicated profile or simply a plain and flat one will do.

• Rigid CCLs: You apply them to most applications. A rigid copper clad board such as an FR-4 laminate gives a solid, unbending foundation.
• Flexible CCLs: You select this when you are required to bend or fold your circuit. They are perfect in wearables, medical device and small electronics.

Base Material

The foundation of your laminate, or core. It defines the fundamental properties. This material is used to offer the structural support of the entire circuit board as well as the insulation. This decision will affect cost as well as high-frequency performance, which is a major decision in your design process.

• Paper Base CCL: A less expensive option (e.g., XPC) is an option in simple, low-cost, consumer electronics devices where performance requirements are minimal.
• Glass Fiber Cloth Base CCL: This is the standard in the industry (i.e., FR-4, FR-5) with the strength and stability necessary for most designs.
• Compound CCL: You use these (e.g., CEM-1, CEM-3) to achieve a balanced combination of properties through the use of a mixture of materials such as glass fiber and paper.
• Special Material Base CCL: But in more advanced applications, you may employ a metal-base CCL, a ceramic-base CCL, or even a high-frequency laminate such as Rogers material.

Resin Material

The resin system bonds the laminate layers, and the resin system determines the electrical and thermal properties of the laminate. It is commonly used in the form of sheets referred to as prepreg during the manufacturing process. The resin is as significant as the base material to get your circuit to the performance that it needs.

• Phenolic CCLs: These are low-cost resins (e.g., XPC, FR-1, FR-2) that can work on simple, single-sided boards.
• Epoxy CCLs: Epoxy CCLs are a widely used and highly versatile resin (e.g., FR-3) that has high durability and performance in most applications.
• Polyester Resin CCLs: You choose these when your design demands specific electrical characteristics that other resins can’t provide.

Performance Characteristics

In some cases, the choice of a laminate depends on a single and critical performance measure. It is usually found in areas such as RF engineering or high-power electronics. To achieve a long-term level of reliability, it is appropriate to match the performance of the laminate to the challenges of your application.

• General Performance CCL: This is your typical workhorse laminate, which can be used in most common daily electronics.
• CCL with High Heat Resistance: This is required in high-power circuits that produce a lot of heat to avoid damaging the board.
• CCL with Low Dielectric Constant: They are required in the high-frequency laminate as they guarantee signal integrity within the RF as well as microwave circuits.
• CCL with Low CTE (Coefficient of Thermal Expansion): You select this on devices subjected to changes in temperature so the stress on the components is minimized.

CCL Materials and Components

In order to get a better understanding of the copper clad laminate, you must be aware of its core materials. All CCL materials are composites of copper foil, reinforcing fabric, plus a resin system. Combined, these components form the broad PCB laminate that becomes the basis of your electronic designs.

Copper Foil

The conductive layer of metal on your copper clad board is copper foil. This electrolytic material is a thin layer that adheres to the insulating substrate. You etch off sections of this foil in the manufacturing process to make the precise conductive traces and pads that form your circuit. Its quality is important for a reliable electrical performance.

Prepreg

Prepreg is a fiberglass sheet impregnated with resin, which you use to bond multilayer PCBs. Manufacturers provide several sizes in thickness and resin content with Standard Resin (SR), Medium Resin (MR), and High Resin (HR). You choose the most suitable one depending on the final thickness, layer structure, and the impedance requirements. Which is important for making a reliable FR-4 laminate.

Reinforcing Fabric

The reinforcing fabric provides your PCB laminate with its mechanical strength and dimensional integrity. Typically, you will encounter woven glass, such as the 7628 style, which is very rigid. In other applications, you may utilize non-woven fiber mats or even paper-based materials, again depending upon the required cost and performance properties.

Resin Systems

A resin system is the fabric that makes everything stick, offering bonding and electrical insulation. Epoxy, polyimide, and PTFE are common resins. Your choice of resin is vital to the performance of the laminate. As an example, a high-frequency laminate will have the required electrical properties made possible by a special resin system such as PTFE.

New Trend of CCL

The future of the PCB industry is decided upon by environmental regulations such as the RoHS. Such a transition requires more heat-resistant and reliable copper-clad laminate. You must therefore learn two key CCL material trends, such as the halogen-free and lead-free laminates. These innovations make your boards effective and compliant.

Halogen-free CCL

Halogen-free CCL material imposes severe limitations on the chlorine (Cl) and bromine (Br) content. Both controlled to less than 900ppm and in total less than 1500ppm in order to meet current environmental requirements. By selecting this option instead of a standard FR-4 laminate, you will experience immense thermal-related benefits. It provides significantly improved heat resistance and dimensional stability to your copper clad board, though at the cost of lower peel strength.

Performance comparisons of halogen-free CCLs with ordinary FR-4 CCLs are given as shown in the table below.

Lead-free CCL

Lead-free CCLs are also designed to handle the higher temperatures of lead-free soldering. They are RoHS compliant and remove chemicals such as PBB and PBDE, and replace them with brominated epoxy resin in these laminates. As compared to standard FR-4 laminate that employs DICY curing, lead-free CCLs employ the PN system (Phenol-formaldehyde resin) of curing. This provides better thermal capability, but it usually decreases peel and bending strength.

Comparison table of different curing systems:

Benefits of Copper Clad Laminate

A proper selection of copper clad laminate has major benefits to your PCB design and production. CCL material has an optimal electrical, thermal, and mechanical character that makes it multifunctional. These advantages allow you to have a ready final product which is reliable and will perform as per expectation and will be affordable to manufacture.

• Excellent Conductivity: The copper layer allows the electric signals to move with minimal resistance, enhancing the performance of your device.
• Superior Heat Dissipation: This PCB laminate has high heat removal capability to pull heat off of sensitive components to avoid overheating, resulting in improved reliability.
• Mechanical Strength: The laminate core adds rigidity to your copper clad board; it helps it avoid bending and breaking.
• Ease of Fabrication: It is easy to etch copper to form complex circuit patterns, and this allows mass production to be efficient and cheap.
• Reliable Soldering: The copper surface provides an ideal base to solder components, which will assist you in making strong, lasting connections.
• Long-Term Durability: A copper clad board withstands corrosion and environmental stress, which generates a longer product life span.
• Dimensional Stability: Your board retains its shape even when exposed to temperature changes, protecting sensitive components and other solder joints.

Applications of CCLs

Copper clad laminate can be found in the heart of almost every electronic device made today. This foundational PCB laminate can be modified to suit the specific requirements of different industries. Whether it’s consumer electronics or a high-level aerospace system, the correct CCL material is important. Let’s explore where these versatile materials are used.

• Consumer Electronics: You find them in smartphones, computers, and wearables. In order to have higher 5G data speed in these devices, you will require a high-frequency specialized laminate.
• Automotive: FR-4 laminate is used in cars due to vibration resistance, but CCL is flexible and enables more complex 3D routing of wires to enhance the reliability of wiring and safety.
• Aerospace and Defense: You select high-temperature, rugged laminates for demanding avionics. Advanced radar systems rely on low-loss materials such as Rogers material to facilitate clear transmission of the signal.
• Medical: You also use the biocompatible, flexible CCLs as medical implants, where a rigid board would fail. These flexible circuits conform to the body and ensure patient safety
• 5G Infrastructure: To develop 5G networks, you require advanced high-frequency laminate. Such materials are necessary to fabricate the high-performance antennas needed to allow millimeter-wave communication.
• IoT Devices: In the case of smaller IoT devices such as smartwatches, a smaller, multilayer copper clad board does the trick. This enables you to pack more functionality into a smaller footprint.

Common Copper Clad Laminate Suppliers

When we are buying copper clad laminate, there are a lot of suppliers everywhere. Depending on your requirements, your choice can range between a generic FR-4 laminate and a high-frequency laminate. In order to guide you through your choices, these are some of the most recognized suppliers with availability on the market:

• Kingboard Laminates
• Panasonic
• Isola Group
• Nan Ya Plastics
• Shengyi Technology
• Rogers Corporation
• Ventec International Group
• Doosan Corporation
• Iteq Corporation
• Mitsubishi Gas Chemical

We collaborate with the best suppliers to obtain the best copper clad board at MV Flex Circuit. We make sure that all CCL materials, from the core to the prepreg, adhere to high-quality standards. This dedication enables us to provide a consistent and high-performance end product to fit your specific requirements.

PCB Manufacturing with Types of CCL In MV Flex Circuit

With more than 20 years as an industry leader, MV Flex Circuit’s expertise is to make anything, from low-volume prototypes to high-volume production runs. All materials are guaranteed to be made of original materials. We use only the highest quality copper clad laminate to create your boards and produce them to your specifications. Whether your design requires a typical FR-4 laminate or a multilayer copper clad board, we follow the strictest standards, ensuring an error-free outcome.

We have the necessary certifications, such as ISO, UL, and RoHS, which ensure you get a high-quality, environmentally friendly final product. We have many types of CCL materials in stock at our factory and can quickly meet your needs. Regardless of whether it is advanced high-frequency laminate, such as Rogers material, or varied solutions like Isola laminate, all PCB laminates that we utilize deliver outstanding performance and reliability. Send us your project Gerber file here: (sales@flexiblepcbboard.com), and get your free DFM check and quotation.

FAQs

Is Copper Clad Better Than Copper?

In the case of PCBs, a clad laminate of copper is much more practical than a solid copper sheet. It offers the needed conductivity using a thin copper layer bonded to a lightweight, supportive substrate. This copper clad board is cheaper and has much needed mechanical strength and heat management to deliver reliable electronics. Using solid copper would be heavy, expensive, and structurally impractical.

How Thick is Copper Clad Board?

The thickness of a copper clad board depends on your application. Copper layer is also measured by ounces (oz), usually 0.5 oz to 2 oz. There is also variation in the thickness of the insulating PCB laminate substrate. We add these two measurements together to make a board with total thickness to meet your particular design, whether this is thin, flexible circuits or thick multilayer boards.

How Much Does Copper Cladding Weigh?

Copper cladding is measured by the weight of ounces per square foot (oz/ft²). A typical 1-oz copper-clad laminate refers to one ounce of copper per square foot of the board. If the application requires flowing more electrical current, you can utilize a heavier weight, e.g., 2 oz or 3 oz. This will enable you to come up with a compromise between the electrical performance of the board and its final weight and cost.

What Are the Most Common Tests Used for Qualifying CCL Materials?

Important qualification tests on a CCL material are its dielectric performance, peel strength, thermal expansion (CTE), and flammability to guarantee functionality.

What Makes Flexible CCLs Able to Bend Repeatedly Without Breaking?

Flexible CCLs utilise flexible core materials such as polyimide, which permits repeated bending of the PCB laminate without cracking or fatigue in the core.

Why Are Ceramic-Filled CCLs Used In 5G And High-Frequency Boards?

Ceramic-filled high-frequency laminate is utilized since, at very high frequencies, the ceramic particles minimize signal loss.

How Do Designers Select the Right CCL For Their PCB Application?

You select the right copper clad laminate by balancing your application’s electrical, thermal, and mechanical needs with your project’s budget.

Conclusion

The choice of a copper clad laminate is one of the most crucial initial steps of a successful PCB project. The electrical performance and the end cost of your board are all affected by the type of CCL you select. Our experts at MV Flex Circuit can assist you with any standard (FR-4) or special high-frequency laminate. Call us now so that you can find the right solution for your design.