PCB Copper Thickness - China PCBA Supplier

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The most often used unit of measurement for copper thickness on printed circuit boards (PCBs) in the industry is ounces (oz). Why describe thickness in terms of weight? Excellent query! The thickness that results from flattening 1 ounce (28.35 grams) of copper to cover 1 square foot of surface area (0.093 square meters) equally is 1.37 millimeters (0.0348 mm). Below is a conversion chart for several units of measurement.

How much Copper do I need?

The majority of PCBs are created using 1 ounce of copper per layer. We'll assume 1 oz finished copper weight on all copper layers if your files don't mention a fab print or other specs. Thickner copper may be required if your design calls for larger voltages, resistance, or impedances. You can use a number of online tools to calculate the required thickness, width, or length of your traces in order to acquire the desired outcomes. Below are links to a couple of these third-party resources.

Copper thickness of PCBs can be specified directly or as the weight of copper per area (in ounce per square foot) which is easier to measure. One ounce per square foot is 1.344 mils or 34 micrometers thickness. Heavy copper is a layer exceeding three ounces of copper per ft2, or approximately 0.0042 inches (4.2 mils, 105 μm) thick. Heavy copper layers are used for high current or to help dissipate heat.

On the common FR-4 substrates, 1 oz copper per ft2 (35 µm) is the most common thickness; 2 oz (70 µm) and 0.5 oz (18 µm) thickness is often an option. Less common are 12 and 105 µm, 9 µm is sometimes available on some substrates. Flexible substrates typically have thinner metalization. Metal-core boards for high power devices commonly use thicker copper; 35 µm is usual but also 140 and 400 µm can be encountered.

PCB Copper Thickness: 1 oz copper (~35µm thick or 1.4 mils) — Standard internal layer copper thickness for "standard construction product for 1 oz and 2 oz finished copper weight selections. This is also the standard starting copper weight on the external layers for PCBs with the 2 oz finished copper weight selection.