20 oz copper thickness in heavy copper pcb

What is a 20 oz Copper PCB?

PCB copper thickness is measured in ounces per square foot (oz/ft2). This designates the weight of copper foil in one square foot of board area, excluding the dielectric substrate. Some standard copper weights are:

• 1 oz – 1 oz/ft2 (35 μm)
• 2 oz – 2 oz/ft2 (70 μm)
• 10 oz – 10 oz/ft2 (350 μm)
• 20 oz – 20 oz/ft2 (700 μm)

So a 20 oz copper PCB has 20 ounces of copper foil per square foot on each metal layer. In terms of thickness, 20 oz copper is approximately:

• 700 μm (0.7 mm)
• 28 mils

This extreme foil thickness enables the greatest power handling and reliability capabilities.

Benefits of 20 oz Copper PCBs

Some key advantages of 20 oz copper PCB technology include:

• Highest current capacity – Ability to sustain extremely high current loads without overheating due to massive copper cross-section.
• Lowest losses – Minimal resistive losses allow highly efficient power transfer and conversion.
• Finest thermal performance – The thick copper acts as a heat spreader keeping components cool.
• Superior shielding – Provides near total EMI isolation from thick uninterrupted planes.
• Extreme reliability – Highly resistant to thermal cycling, electromigration and physical stresses over decades.
• Low voltage drop – Negligible voltage loss along power distribution paths due to minimal resistivity.
• High power density – Maximum possible power can be delivered through a PCB footprint.
• Component integration – Embed heavy power components into 20 oz copper inner planes.

20 oz copper represents the leading edge of PCB material technology for the most extreme electrical and thermal demands.

Key Manufacturing Capabilities for 20 oz Copper

To reliably fabricate 20 oz copper multilayer boards, PCB manufacturers must demonstrate several advanced capabilities:

• Registration Accuracy – Within 0.10mm between layers to prevent misalignment.
• Plating Aspect Ratios – Reliable copper plating down to at least 20:1 hole aspect ratios.
• Lamination – Use of high fillers in prepreg and precise pressure control during bonding.
• Etching – Fine line etching capability down to 1 mil line/space.
• Hole Wall Quality – Excellent resin coating of drilled hole walls with no pull-away.
• Surface Finish – Highly uniform thick gold plating over very coarse surfaces.
• Peel Strength – Interlaminar peel strength over 15 N/mm.
• Via Filling – Pore-free copper plating fill of high aspect through holes.
• Drilling – Straight vertical holes through >0.7 mm copper.
• Panel Flatness – Overall thickness variation under 5% with minimal bow or twist.
• Process Control – Mature statistical process monitoring and control systems.

These capability indicators validate whether a PCB company can reliably manufacture 20 oz multilayer boards.

Potential Applications of 20 oz Copper PCBs

Some examples of products that can utilize thick 20 oz copper PCB technology include:

• Electric vehicle powertrain – Motor controllers and battery management systems.
• Industrial power supplies – High capacity UPS and DC power systems.
• Heavy-duty motor drives – Drives for large electric motors and compressors.
• High power RF amplifiers – High frequency amplifiers for radio transmission.
• Power distribution – Switchgear, bussbars and junction boxes.
• Traction systems – Substations, converters and distribution for rail infrastructure.
• Power generators – Controls and distribution for power generators.
• Power converters – High capacity AC-DC and DC-DC converters.
• Renewable energy – Solar/wind power controllers and switching systems.

For such extreme high power applications, 20 oz copper provides the highest performance and reliability.