A heavy Copper PCB is a double-sided or multilayer PCB with a copper base thicker than 3 oz (105µm). The additional Cu thickness increases the current carrying capacity with high endurance to thermal strain.

Heavy Copper PCBs are designed to handle high current loads or PCBs populated with components that generate high heat with a need for heat distribution into the surrounding substrate material. This type of PCB is characterized by its high copper weight, typically greater than 3 oz/ft², and can be used in a wide range of electronic applications that require high power dissipation and heat management.

Base Material: The base material used in a Heavy Copper PCB are often High Tg. FR4, BT epoxy or GPY Polyimide
Thickness: 0.4 mm to 6,35mm
Copper Weight: 4 oz/ft² to 15 oz/ft² – Low qty. and samples up to 20 oz/ft²
Lines and Spaces: Dependent on Cu Weight (thickness)
Vias: Via types to be used depends on the construction and Cu weight.
Layer Count: 2 to 14 layers
Surface Finish: ENIG, HASL, LF HASL, Immersion Ag, Immersion Sn, Galvanic Ni/Au.
Solder Mask: The Cu thickness on outer layer determines the solder mask thickness needed to provide sufficient coverage and protection of the Cu pattern.

When current flows along a trace, the power loss results in localized heating. IPC-2221A Generic Standard on Printed Board Design contains formulas to calculate the current carrying capacity and related temperature rise. The amount of current a copper circuit can safely carry depends upon the base material and the application’s operational temperature, since heat rise, and current flow are related. High Tg materials are often selected for Heavy copper PCBs.

With its exceptional ability to support high voltage and temperature, heavy copper is mainly used in Automotive, Electrical Power Distribution, Power Converters, Aerospace, Medical, Welding Equipment, Power Supplies and by Solar Panel Manufacturers.