To FPC copper foil

The conductive part of a flexible printed circuit board (FPC) is made of copper, and copper foil is used in its manufacture. This page describes FPC copper foils such as rolled copper foil and electro-deposited copper foil for flexible printed circuit boards (FPC).

What is copper foil in a flexible printed circuit board (FPC)?

Flexible printed circuit board (FPC) materials consist of a copper foil laminated to a base material such as polyimide film or liquid crystal polymer.FPCs are used in a wide variety of applications. Flexible printed circuit boards (FPCs) need to be flexible and thin because they are repeatedly bent and used while bent. This is where copper foil, with its thin film and flexibility, is used.

Types of copper foil

Rolled copper foil

Rolled copper foil of the desired thickness is produced by stretching a copper ingot thinly with a rolling roll and then repeatedly stretching it thinner with another rolling roll. Since rolled copper foil is hard only when stretched thin, it is annealed to make it flexible. In addition, the surface is specially treated so that it adheres to flexible printed circuit board (FPC) boards.

To produce thin rolled copper foil, the process of stretching it thinly with a rolling roll is repeated many times, which increases the cost.For flexible printed circuit board (FPC) applications, rolled copper foil in 1 oz (35 µm thick), 1/2 oz (17.5 µm thick) and 1/3 oz (12 µm thick) foils are commonly usedRolled copper foil is used mainly as a copper foil for flexible printed circuit boards (FPC). Rolled copper foil has superior flexibility compared to electro-deposited copper foil and is mainly used as copper foil for flexible printed circuit boards (FPC).

Electrolytic copper foil

Electrolytic copper foil is a sheet of copper deposited on a cathode by electrolysis. Traditionally, electro-deposited copper foil was rarely used because it was too thin and vulnerable to bending, and rolled copper foil was mainly used. In recent years, however, electro-deposited copper foil for flexible substrates has been commercialized.

Electro-deposited copper foil for flexible substrates has flexibility equivalent to that of rolled copper foil through heat treatment and other means, and is given properties that make it resistant to bending.The most commonly used thicknesses are one-ounce foil (35 µm thick), one-half ounce foil (17.5 µm thick), and one-third ounce foil (12 µm thick), which are the same as rolled copper foil.. The advantage of electrolytic copper foil is that it is less expensive to produce than rolled copper foil.

Plated copper foil

In recent years, thinner copper foils are required for flexible printed circuit board (FPC) production as circuits become finer and finer. However, both rolled copper foil and electro-deposited copper foil are difficult to handle when the thickness is less than 10 µm.Plated copper foil is used when thin copper foil is required.

Copper plating is applied directly to the base material to form a thin plated copper foil layer. A conductive seed layer is formed by electroless plating or sputtering, and electrolytic plating is applied on top of the seed layer to obtain a plated copper foil layer. It is used in the semi-additive method for manufacturing flexible printed circuit boards (FPC) and in the metallization method for making FPC 2-layer materials.

Summary

Copper foil is an important material that forms the conductive part of a flexible printed circuit board (FPC).There are three types of copper foil: rolled copper foil, electro-deposited copper foil, and plated copper foil, each of which has its own advantages and disadvantagesThe following is a brief overview of the material selection process. Learn about their characteristics and use them to help you choose the right materials.

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