Definition of Heavy Copper PCB

Heavy copper does not have a set definition per IPC. However, the industry generally accepts the definition to be the use of 3 ounce copper or higher in inner and/or outer layers of a printed circuit or power distribution board.

Applications for Heavy Copper

Heavy copper can be used for a variety of purposes, including, but not limited to, high power distribution, High current applications, thermal distribution for good thermal management, planar transformers, and power convertors.

Design Guide for Heavy Copper PCB

Min conductor width/spacing

Inner layer
Copper foil thickness	Min. conductor width	Min. conductor spacing
140µm	300µm	300µm
210µm	500µm	500µm
400µm**	900µm	900µm

Outer layer
Copper foil thickness		Min. conductor width	Min. conductor spacing
Basis copper	Final thickness*
140µm	175µm	350µm	350µm
210µm	245µm	500µm	500µm
400µm**	435µm**	900µm	900µm

Capability of Heavy /Thick Copper PCB

   Base material: FR4/Aluminum

   Copper thickness: 4 OZ~6OZ

   Outline: Routing, punching, V-Cut

   Soldermask: White/Black/Blue/Green/Red Oil

   Surface finishing: Immersion Gold, HASL, OSP

   Typical conductor width/spacing/thickness tolerance is +/-20%, although tighter tolerance is achievable.

   A circuit board trace, depending on its size and manufacturing process, may not be rectangular in shape. Heavy copper conductors can significantly add to the overall board thickness.

   Additive (plating) processed are preferred to subtractive (etching) processes but are more expensive.

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