A Complete Introduction To Copper Clad Laminate (CCL) (2022)

Copper Clad Laminate is an insulating plate coated or cladded with copper foil and produced by stacking an impregnated (prepreg) sheet of resin over a substrate (the base material) suchlike glass or paper, under high temperature and pressure. It is the basis of every circuit and PCB. When used in the manufacturing of multi-layer PCBs, it is known also as a CORE. The printed circuit board manufactured from CCL is a combination of conducting and insulating layers, vials, pads of copper tracks, holes, and other components.

Copper clad laminate consists basically of a glass fiber substrate laminated using copper foils and epoxy resins. The glass fiber can also be termed “prepreg” because it is integrated with epoxy resin. The glass fiber alongside other substrate materials such as glass, paper, fiber cloth, and water pulp is generally known as reinforcing materials. Copper clad laminate is the most commonly and significantly used substrate in the fabrication of PCBs. It is now being used in most PCBs, whether for industrial circuit boards or consumer electronics.

Glass-fabric and paper-based copper clad laminate are two of the major products (by output) in this market segment, contributing about 61% and 17% respectively of entire China’s CCL in 2013. The CCL industry has grown significantly and innovatively in the past years with Southeast Asia and China having the fastest growth and development. Key manufacturers in the industry globally have consequently taken measures such as product transformation and capacity expansion to strengthen the business of copper clad laminate production. The output of the world’s copper clad laminate in 2013 saw an annual increase of about 17.9% to 720,000,000 square meters, mainly from Asia (about 95.6%); particularly China, which produces a copper clad laminate with an output of 480,000,000 square meters in the same year, which is an increase of 6.8% from the previous year, accounting for about 67% of world production.

Copper clad laminate has a wide range of applications including:

• Consumer electronics circuit board
• High-speed mobile communications such as smartphones, 5G, and 4G-LTE base stations antenna equipment.
• Automotive industry such as in Advanced Driver Assistance Systems (ADAS)
• Avionics (Radar communications)
• Electric power generation
• Welded tanks
• Sheathing of Offshore platform
• Shipbuilding
• Steam condensers
• Hydraulic bushings
• Heat exchangers
• Pressure vessels
• Nuclear materials storage
• Desalination plants
• Missile components
• Wearable parts of expansion joints
• Metal casting molds and dies
• Oil exploration and others

The quality and performance of a copper clad laminate are dependent on the below factors and should be done by PCB Fabrication Houses.

• Size: Given that copper clad laminates are the base or substrate material for PCBs, they must be made according to specific size requirements that correspond with the PCB. Parameters to be considered include the length, breadth, warpage, and diagonal deviation; each of these parameters must meet specific standards.
• Appearance: A copper clad laminate of syndrome quality must be plain, sleek, and polished in appearance. Scratch, dent, bubble, pinhole, wrinkle, or resin point on the copper foil during production can reduce the performance of the copper clad laminate and PCB.
• Physical performance: A copper clad laminate physical performance can be affected by these parameters: dimensional stability, bending strength, peel strength, punching quality, heat resistance namely thermal stress, Time to delamination-T300, T288, and T388, and others.
• Chemical performance: The chemical performance of copper clad laminates must meet these requirements: resistance to chemical reagents, flammability, Z-CTE (Z-axis Coefficient of Thermal Expansion), Glass transition temperature (Tg) for mechanical stability, dimensional stability, and others.
• Electric performance: This quality and performance are important for PCBs and the copper clad laminate must be designed for the best electric performance to meet the required standards such as Dielectric Constant (Dk), Surface Resistance, Volume Resistance, Dielectric Loss Tangent (Df), Dielectric Breakdown Voltage, Comparative Tracking Index (CTI), Electric Strength, etc.
• Environmental performance: A copper clad laminate must also meet certain environmental requirements like eco-emissions, water absorption, etc.