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A Beginner’s Guide to Copper Clad Laminates: Understanding the Basics


Copper Clad Laminate (CCL), also known as copper clad board. That is a crucial material used in the manufacturing of printed circuit boards (PCBs). It’s made by applying resin to electronic fiberglass cloth or other reinforcing materials. and then covering one or both sides with copper foil through a hot-pressing process. CCLs serve essential roles in PCBs, providing support, insulation, and interconnection. They directly impact signal transmission speed, energy loss, and circuit impedance. The quality, performance, and cost-effectiveness of PCBs largely rely on the characteristics of CCLs. Typically, CCLs make up 20% to 40% of the total PCB production costs. showcasing their significant importance in the manufacturing process.

copper clad laminate sheet

Importance of understanding copper clad laminates for beginners:

The price of CCL occupies 20-40% of PCB, so CCL is one of the main factors affecting the price of PCB. As a PCB beginner, to understand the use of CCL, type, production and other information. To be able to choose the right CCL for their projects, so that your project can be more competitive!

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What is Copper Clad Laminate?

A. Definition and explanation of copper clad laminates:

Copper clad laminates (CCLs) are composite materials used as substrates for printed circuit boards (PCBs). They consist of a non-conductive base material, typically fiberglass (FR4). with a thin layer of copper foil bonded to one or both sides. This copper layer acts as the conductive pathway for electronic signals. allowing components to be soldered onto the PCB.

B. Composition of copper clad laminates:

  • Base Material:Usually fiberglass (FR4), epoxy resin, or phenolic paper. This base material provides mechanical support and insulation.
  • Copper Foil: A thin layer of copper foil bonded to one or both sides of the base material. The thickness of the copper foil can vary depending on the application requirements.
  • Adhesive Layer: A bonding agent or adhesive used to adhere the copper foil to the base material. ensuring strong adhesion and electrical conductivity.

C. Types of copper clad laminates:

Based on the mechanical rigidity:

  • Rigid copper clad laminates (RCCL)
  • Flexible copper clad laminates (FCCL)



Depending on different insulation materials and structures:

  • Organic resin-based copper clad laminates
  • Metal-based copper clad laminates
  • Ceramic-based copper clad laminates.

When it comes to the thickness of copper clad laminate

  • Thick laminates (ranging from 0.8 to 3.2mm including copper)
  • Thin laminates (with a thickness range of less than 0.78mm excluding copper).

Regarding the reinforcement materials of copper clad laminates:

  • Glass cloth-based copper clad laminates
  • Paper-based copper clad laminate
  • Composite-based copper clad laminates (CME-1, CME-2).

Flame retardancy grade:

  • Flame retardant laminates
  • Non-flame retardant laminates

According to UL standards (UL94, UL746E, etc.). rigid CCLs are classified into four different grades: UL-94V0, UL-94V1, UL-94V2, and UL-94HB.

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Properties and Characteristics

A. Electrical properties of copper clad laminates:


The copper layer in CCLs provides high electrical conductivity. allowing efficient transmission of electrical signals across the PCB.

Dielectric Constant:

The base material of CCLs typically has a low dielectric constant. minimizing signal loss and ensuring accurate signal transmission.

Insulation Resistance:

CCLs offer good insulation resistance. preventing unintended electrical connections and ensuring the integrity of circuitry.

Impedance Control:

CCLs manufactured with precise impedance control. essential for high-frequency applications where signal integrity is critical.

B. Thermal properties of copper clad laminates:

Copper clad laminates possess favorable thermal properties. contributing to the reliability and performance of electronic devices. These thermal properties include:

Thermal Conductivity:

Copper has excellent thermal conductivity. allowing efficient dissipation of heat generated by electronic components on the PCB.

Thermal Resistance:

CCLs have low thermal resistance. enabling heat to dissipate quickly from the PCB surface and preventing overheating.

Thermal Stability:

The base material of CCLs, such as FR4 or polyimide, exhibits good thermal stability. maintaining mechanical integrity and electrical performance over a wide temperature range.

C. Mechanical properties of copper clad laminates:

In addition to their electrical and thermal characteristics. copper clad laminates possess robust mechanical properties. ensuring durability and reliability in various applications. These mechanical properties include:

Flexural Strength:

CCLs have high flexural strength, allowing them to withstand bending. and mechanical stress without deformation or damage.

Tensile Strength:

The bond between the copper foil and the base material in CCLs provides high tensile strength. ensuring the integrity of the conductive pathways even under mechanical strain.

Dimensional Stability:

CCLs exhibit good dimensional stability. maintaining consistent thickness and flatness during fabrication and operation.

Resistance to Environmental Factors:

CCLs are resistant to environmental factors such as moisture. chemicals, and temperature fluctuations, ensuring long-term reliability in harsh operating conditions.

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Applications of Copper Clad Laminates

A. Industries Using Copper Clad Laminates:

Copper clad laminates are crucial in many sectors for their durability and adaptability. Key industries include:

  • Electronics: The base for PCBs in gadgets like smartphones and computers.
  • Aerospace and Defense: Vital for systems in communications and avionics.
  • Automotive: Used in systems like ECUs and navigation.
  • Telecommunications: Supports signal handling in network equipment.
Metal Core PCBs in Automotive Power Supply Systems

B. Electronics Manufacturing Uses:

Copper clad laminates power a wide range of electronic manufacturing applications, such as:

  • Consumer Electronics: Found in devices like phones and TVs for circuitry.
  • Industrial Electronics: Key in systems for control and automation.
  • Medical Electronics: Essential for medical tools and imaging devices.
  • LED Lighting: Provides connectivity and heat management for LEDs.

The Thickness of Copper Clad Laminate

CCL thickness is about how thick a Copper Clad Laminate (CCL) is. CCLs are materials we use to make printed circuit boards (PCBs). with a core material like fiberglass or epoxy covered in copper on one or both sides. The copper’s thickness usually gets measured in ounces per square foot. which tells us its thickness in mils (thousandths of an inch) or micrometers. For example, 1 oz of copper per square foot is about 1.4 mils thick, or roughly 35 micrometers.

The core material’s thickness is in millimeters (mm) or inches. Common thicknesses include very thin sheets for flexible circuits. and standard sizes like 0.8 mm, 1.6 mm, or 2.4 mm for other uses.

The total thickness of a CCL matters for the PCB’s stability. how well the circuit works, and fitting with components and connectors. Choosing the thickness involves balancing durability, flexibility. electrical needs, cost, and how easy it is to make.

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How Copper Clad Laminates are Manufactured ?

A. Overview of the manufacturing process:

The journey of making copper clad laminates (CCLs) includes picking materials. getting them ready, sticking them together, and checking their quality. Here’s how it goes:

how is CCL(copper clad laminate)produced?

Material Selection:

We pick top-notch materials like fiberglass (FR4), epoxy resin, or polyimide. aiming for the needed properties and application demands.


We clean, dry, and apply an adhesive layer to the base material, getting it ready for the copper foil bonding.


We attach thin copper foils to one or both sides of the base material using heat and pressure. The adhesive makes sure the copper sticks well to the base.


We press the bonded layers under high heat and pressure to make the structure solid and even.


We trim the laminated sheets, drill holes for mounting components. and treat the surface to improve soldering and fight corrosion.

Quality Control:

We keep a strict eye on every step to make sure the final copper clad laminates are perfect and reliable.

B. Key steps in production:

Material Prep:

We get the base materials ready by cleaning, drying, and adding an adhesive.

Copper Foil Bonding:

We press thin copper foils onto the base material with heat and pressure for a strong bond.


We use a press to heat and squeeze the layers into a solid, even structure.

Trimming and Drilling:

We cut the sheets to size and drill holes accurately for component mounting.

Surface Treatment:

We treat the surfaces to boost solderability and resist corrosion, improving circuit performance.

C. Quality control measures:

Raw Material Checks:

We inspect the base materials and copper foils to make sure they meet our standards.

Process Watch:

We closely monitor the heat, pressure, and bonding time during lamination for the best bond and uniformity.

Size and Shape Checks:

We measure the finished laminates to make sure they fit the specs exactly.

Electrical Tests:

We test the laminates to confirm their electrical conductance. insulation, and other key properties.

Visual Checks:

We look over the finished products for any issues like delamination or surface flaws.


We document every detail of the production process and materials. keeping track for accountability and quality assurance.

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By understanding the properties and applications of CCLs. beginners can pave the way for innovation and problem-solving in electronic circuit design. As you embark on your journey in this field. consider partnering with GESPCB for expert guidance and high-quality CCL solutions. With our expertise and commitment to excellence. we’re here to support your endeavors and help you achieve success in your electronic projects. Explore our range of CCL products and services today. and unlock the full potential of your designs with GESPCB.

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