Heavy Cu Resource Center

Fabrication Methodologies

Specialized Etching and Plating methods for Heavy Cu Fabrication


There are three primary methods to create Heavy Copper PCB designs.

1.  Etch-Down
This is the traditional methodology to create printed circuit boards.  Essentially, in the case of a PTH design, we start with a base copper 1 ounce less than the desired finished copper weight and plate up to the target copper weight.  We then would etch down the base copper to the base laminate in order to create the design features (circuits, pads, etc.).  The challenge with heavy copper designs is that most fabricators and their equipment are capable of only standard copper weights (2 ounce or less).

2.  Plate-Up:
Instead of plating the typical 1 ounce to the base copper of surface features to achieve target copper weight, this methodology requires starting with a copper weight significantly less than the target.  Then by repeating a series of process steps of image through plating you achieve the target copper weight.

3.  Hybrid:
This is the most effective method of combining digital and power requirements.  Basically the designer buries the heavy copper features on the inner layers and utilizes standard copper weights on the outer layers.  This enables the use of finer pitch components while at the same time addressing high power requirements.

Extreme Heavy Cu Design & Fabrication Comparison Chart
  Etch-down Plate-up Hybrid
Cost Medium
High Standard
Process flow Standard Complex Standard
Min line / space Large Medium Standard
Materials 6oz. max / up to 20oz. (non UL) max recommended 3oz. 6oz. max / up to 20oz. (non UL)
Supplier availability Limited Limited Standard
Solder mask Trace fill ink; spray method Standard Standard
DFM rules Standard Variable Standard
Failure modes Standard HIgh Standard
Cu weight variation Standard Due to plating variation Standard
Lead times Standard Long Standard
Level sidewalls Yes No Yes
SMT compatible Dependant on Cu Weight Yes Yes

About Us

Domestic PCB Fabricator

Bare printed circuit board manufacturer (NAICS: 334412)
Romulus, MI (since 1985)
(734) 941-8100

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