Printed Circuit Board Material Properties

Conductors on different layers are connected with vias which are copper plated holes that function as electrical tunnels through the insulating substrate.

Printed circuit board material properties.

They can be as simple as one or two layers of copper or in high density applications they can have fifty layers or more. These are commonly referred to as copperclad laminates. A printed circuit board can have multiple copper layers. Multi layer boards sandwich additional copper layers between layers of insulating material.

Surface leakage tracking the surface resistivity of a board depends on the material the condition of the surface and the relative humidity of the surroundings. Typical values for glass epoxy laminates at 60 70 rh are 10 13 to 10 14 w sq 4 4 for an explanation of this unit see conductors and insulators. Here is an overview of the most important properties to consider for any dielectric material. The most common dielectric material is fr 4 but before selecting it for your board you must carefully consider its properties.

A two layer board has copper on both sides. Like all dielectric insulators the material on a printed circuit board must have high resistivity preferably in the range of 10 3 to 10 10 megaohm centimeters. A thin layer of copper foil is laminated to one or both sides of an fr 4 glass epoxy panel. Conductive copper tracks are printed or etched onto this con conductive base substrate.

The last of those layers substrate is made of fiberglass and is also known as fr4 with the fr letters standing for fire retardant. Fr 4 is a common material for printed circuit boards pcbs. External factors like heat cold and moisture can have an impact on a material s resistivity. Printed circuit materials have copper clad surfaces for the fabrication of electronic and electrical circuitry on printed circuit boards pcbs printed wiring boards pwb and flexible circuits.

Pcb materials for base of a printed circuit board can be resin based fiberglass based epoxy glass metal board flame retardant ul94 vo ul94 v1. This material is very thin 1 2 and 4 mil cores flexible lightweight has very low moisture absorption as well as a high chemical resistance. Lcp is a unique thermoplastic material that can be used to manufacture multilayer printed circuit boards. Printed circuit boards pcbs are usually a flat laminated composite made from non conductive substrate materials with layers of copper circuitry buried internally or on the external surfaces.

When ordering a copper clad laminate board the fr 4 and copper thickness can both vary and so are specified separately.