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20 oz Copper PCB Design Guideline for High Current
Wednesday, July 23rd, 2025

How to design 20 oz copper PCB for high current? Let’s explore thickness, specifications, benefits, application and design guideline for 20 oz copper PCB.

Are you worried about these problems?

  • PCB circuits are prone to overload and burn in high current scenarios.
  • The heat dissipation solution takes up space and is expensive.
  • The yield rate of thick copper plate processing fluctuates greatly.

The services Best Technology can provide:

  • The 20oz ultra-thick copper foil design has a current carrying capacity that is 3 times that of conventional PCBs. It can stably carry 150A continuous current through thermal simulation verification.
  • The patented copper-based composite structure and built-in heat conduction channel realize PCB self-heating, saving 40% of the cost of peripheral heat dissipation components.
  • The unique step-by-step pressing process, combined with full-process quality control, ensures that the batch production yield rate is stable at more than 95%.

Welcome to contact Best Technology if you have any inquiry for copper PCB: sales@bestpcbs.com.

What Is a 20 oz Copper PCB?

A 20 oz copper PCB utilizes a 700μm-thick copper layer (equivalent to 20 ounces per square foot), significantly exceeding standard copper weights to achieve exceptional electrical performance. This extreme copper thickness minimizes resistive losses (I²R heating) while enabling current handling capabilities exceeding hundreds of amperes, making it essential for high-power systems requiring stable operation under intense loads.

Its substantial copper mass provides superior thermal conductivity (>380 W/mĀ·K), efficiently dissipating heat toward heatsinks or enclosures to maintain operating temperatures within safe limits. Fabrication demands specialized processes like stepped lamination and high-temperature resins to prevent delamination, ensuring structural integrity during repeated thermal cycles. These boards serve critical roles in electric vehicle charging systems, industrial power converters, and energy distribution infrastructure where reliability under sustained high loads is non-negotiable.

What Is a 20 oz Copper PCB?

How Thick Is 20 oz Copper PCB?

The thickness of a 20 oz copper layer in a PCB is approximately 700 micrometers (μm) . This measurement is derived from the industry standard where 1 ounce (oz) of copper per square foot equals roughly 35 μm in thickness, utilizing copper’s density and unit conversion principles.
Due to manufacturing tolerances, the actual copper thickness may vary by ±10%, resulting in a typical range of 630 μm to 770 μm for 20 oz copper PCBs.

20 oz Copper PCB Specifications

ParameterSpecification
Copper Thickness700μm (20 oz) ±10%
ā€ŒCurrent Capacity100A+ continuous
Base Material1-3mm thick copper core (99.95% purity)
ā€ŒThermal Conductivity400W/(mĀ·K) (copper core)
Insulation Layer50-100μm ceramic (Alā‚‚Oā‚ƒ/AlN), >3kV breakdown
ā€ŒMin Trace Width12mil (0.3mm)

Benefits of 20 oz Copper Base PCB

  • Extreme Current Handling – Supports 100A+ continuous current (3x standard PCBs), ideal for high-power applications like EV chargers and industrial inverters.
  • Superior Thermal Management – Copper core dissipates heat 60% faster than aluminum, reducing hotspots and extending component lifespan.
  • Space-Saving Design – Thick copper (700μm) allows narrower traces (12mil vs. 6mm for equivalent current), saving PCB area.
  • High Reliability – Resists thermal cycling fatigue, 3x longer lifespan in high-temperature environments vs. standard PCBs.
  • Lower Resistance – Pure copper base reduces conductive losses by 40%, improving energy efficiency.
  • High-Frequency Performance – Smooth copper surface (Ra<0.5μm) minimizes signal loss for RF/5G applications.
  • Mechanical Strength – Copper core prevents warping under heavy components (e.g., IGBT modules).
Benefits of 20 oz Copper Base PCB

When to Use 20 oz of Copper PCB?

Applications of 20 oz copper PCB:

  • High-Power Electronics – Ideal for EV charging systems, industrial motor drives, and power converters requiring minimal resistance and efficient heat dissipation.
  • RF & Telecommunications – Best for 5G base stations and satellite communication equipment where signal integrity and thermal stability are crucial.
  • Heavy-Duty Power Switching – Suitable for welding machines, server power supplies, and UPS systems handling extreme current surges.
  • High-Brightness LED Systems – Used in stadium lighting and industrial LED arrays where active cooling is necessary to maintain performance.
  • Automotive Power Modules – Optimal for EV inverters and battery management systems needing compact, high-current designs.
  • High-Temperature Industrial Equipment – Applied in machinery where prolonged thermal cycling and reliability are key factors.
When to Use 20 oz of Copper PCB?

What Is Difference between 16 oz and 20 oz Copper PCB?

Comparison Aspect16 oz Copper PCB20 oz Copper PCB
ā€ŒCopper Thicknessā€Œ~560 μm~700 μm
ā€ŒCurrent Carrying Capacityā€Œ (at same trace width)Handles high currents (e.g., ~80A for 10mm width)Handles high currents (e.g., ~80A for 10mm width)
ā€ŒThermal ManagementGood heat dissipation, suitable for moderate-power appsSuperior heat spreading, minimizes hotspots by 15-20%
ā€ŒSpace Efficiencyā€Œ (trace width for same current)Requires wider traces (e.g., 6mm for 30A)Enables narrower traces (e.g., 4.8mm for 30A), saving PCB area
Manufacturing Cost & DifficultyHigher cost than standard PCBs, moderate etching challengesHighest cost due to complex etching and material use
ApplicationsIndustrial motor drives, UPS systemsEV fast chargers, server power supplies (>500A surges)

How to Design 20 oz Copper PCB for High Current?

20 oz Copper PCB design guideline for High-Current

1. Copper & Trace Design

  • Current Capacity: Use I = 0.048Ć—Ī”T^0.44Ɨ(WƗH)^0.725 (IPC-2221). 20 oz copper (700µm): 15mm width supports ~100A at Ī”T=30°C.
  • Trace Compensation: 2 oz: Add 0.2mm width; spacing ≄0.25mm; 4 oz: Critical traces ≄1.5mm wide; spacing ≄0.4mm.
  • Plane Layers: Use full-layer planes for currents >30A (lower impedance, better heat spread).

2. Thermal Management

  • Via Arrays: Place ≄0.3mm vias under power devices (pitch ≤1.5mm). Fill with thermal paste to connect to bottom copper, cutting thermal resistance by >50%.
  • Exposed Copper: Remove solder mask for direct air cooling (2–3Ɨ heat dissipation). Apply ENIG/HASL for oxidation resistance.
  • Embedded Copper: For >50A, embed 1.5mm copper blocks in FR4 layers (reduces local temps by ≄30°C).

3. Layer Stackup

  • Multilayer Structure: “Sandwich” stackup (power layer – insulating layer – 2 oz copper + 1mm aluminum). Inner layers use stepped copper (0.5–4 oz) to reduce Z-axis stress.
  • Prepreg: High-resin (e.g., 2116) for 85%+ fill. Board edges reinforced with epoxy slots (30% stronger).

4. Manufacturing

  • Etching/Plating: Use LDI for 3/3mil traces; pulse plating for ≄25µm hole copper (uniformity >90%).
  • Lamination: Pre-press 180°C/40min/15kg/cm²; full press 200°C/90min/25kg/cm²; cool ≤3°C/min.

5. Safety & Compliance

  • Clearance: AC/DC ≄6mm; creepage ≄8mm/1000V (IEC 60664).
  • Protection: 132°C TCO + current sensor; TVS diodes ≤5mm from connectors.
  • Isolation: Optocouplers/transformers for AC-DC; primary-secondary spacing ≄8mm.

6. Verification

  • Thermal Sim: ANSYS Icepak/Simcenter for device temps (MOSFET Tj <125°C). Current Density: SIwave maps; avoid >500A/cm² (prevents electromigration).
  • Testing: Infrared scan for hotspots; key paths Ī”V <2% (e.g., <0.24V for 12V).

Client Design Tips:

  • Cost vs. Performance: 20 oz suits 50A+ but needs via arrays/aluminum.
  • Fabricator: Choose LDI/pulse-plating vendors.
  • Lead Time: Add 3–5 days for custom stacks; confirm impedance upfront.
How to Design 20 oz Copper PCB for High Current?

Why Choose Best Technology as Your Copper PCB Manufacturer?

  • 24-hour rapid prototyping: shorten the R&D cycle by 50% and accelerate product launch.
  • 1 Piece MOQ & Competitive Pricing – No hidden costs, offering the best value without compromising quality.
  • Thermal Solution Consulting: Free CFD simulation identifies optimal airflow paths.
  • Turnkey Solutions – Full-service PCB manufacturing from design to delivery, accelerating your product’s time-to-market.
  • ISO 14001/ISO 13485 certification: medical/automotive customers are exempt from secondary testing, and compliance costs are reduced by 30%.
  • Free DFM (Design for Manufacturability) Analysis: Optimizes PCB layouts to reduce material waste, lower production costs, and avoid late-stage design revisions.
  • Rigorous quality control: directly reducing your maintenance costs by 40% while extending product lifespan.

If you have any request for copper base PCB, welcome to contact us to get a free quote: sales@bestpcbs.com.

Is Thicker Copper PCB Always Better? How to Choose Suitable Copper Thickness?
Monday, May 26th, 2025

In high-power electronics, thermal management is everything. Whether you’re designing LED modules, motor controllers, or power converters, one of the first decisions you’ll make is selecting the right copper thickness for your copper core PCB.

It’s tempting to assume that more copper is always better. After all, thicker copper offers lower resistance and better heat conduction. But here’s the truth: while thicker copper can enhance performance, it also introduces new challenges—in cost, manufacturability, and even thermal efficiency in certain contexts.

In this article, we’ll dive into how copper thickness affects heat dissipation, mechanical integrity, and overall PCB performance. You’ll also learn how to find the sweet spot—balancing copper thickness with practical requirements.

How to Choose Suitable Copper Thickness?

What Does Copper Thickness Really Do in a PCB?

Copper thickness in a PCB is typically measured in ounces (oz), where 1 oz equates to approximately 35 micrometers of thickness. The thicker the copper, the more current it can carry and the more heat it can dissipate—up to a point.

For example:

  • 1 oz copper is standard in many applications like consumer electronics or low-power LED boards.
  • 2 oz–3 oz copper is often used in medium- to high-power applications, such as telecom equipment or automotive control modules.
  • 4 oz–6 oz copper or more is reserved for ultra-high-current or extreme thermal environments, like industrial drives or inverters.

In a copper core PCB, the copper layer not only serves as a trace but also acts as a heat conduit. But simply adding more copper isn’t always the best strategy—it needs to be balanced with mechanical, thermal, and design constraints.

How to Choose Suitable Copper Thickness?

How Does Thicker Copper Affect Thermal Conductivity?

Thermal conductivity is the rate at which heat passes through a material. Copper’s thermal conductivity is excellent—about 398 W/mĀ·K—much higher than FR4 (0.25 W/mĀ·K) or aluminum (205 W/mĀ·K). Thermal conductivity improves as copper gets thicker—up to a point.

  • A 1 oz (35µm) copper layer offers good heat flow for standard loads.
  • 2 oz (70µm) or 3 oz (105µm) copper layers are used for medium-to-high power circuits.
  • Ultra-thick copper like 6 oz (210µm) or more is suitable for extreme applications like power inverters or motor drivers.

But while thicker copper improves thermal conductivity, it also increases thermal mass, which can slow down heat transfer in fast-cycling circuits. That means copper core PCBs with ultra-thick copper aren’t always the most efficient in dynamic thermal environments.

What Happens to Mechanical Strength as Copper Gets Thicker?

A copper core PCB with heavy copper also becomes more rigid. This can be beneficial in harsh environments (e.g. EV chargers, industrial robots) where vibration or mechanical shock is a concern.

However, ultra-thick copper comes with drawbacks:

  • Reduced flexibility: Too much copper can crack during mechanical stress.
  • Higher internal stress: Thicker copper can warp other layers if not carefully designed.
  • Drilling and routing challenges: High copper thickness limits hole aspect ratio and increases the risk of burrs or tool breakage.

In short, thicker copper increases strength but decreases the PCB’s resilience during assembly or use.

Manufacturing Challenges of Thick Copper Core PCBs

As copper thickness increases, so does the cost—not just of materials, but also in processing:

  • Etching Control: The deeper the copper, the harder it is to maintain precise trace widths and spacing. Over-etching or under-etching can occur, especially with high-aspect-ratio designs.
  • Drilling Difficulties: Thick copper increases drill wear and may require specialized bits. This adds time and cost.
  • Solder Mask Issues: Solder mask adhesion becomes less reliable with thick copper due to surface tension and lack of anchor points.
  • Fine-pitch traces are harder to produce with heavy copper.

A copper core PCB with 3 oz copper may cost up to 1.8x more than a standard 1 oz version. And a 6 oz copper design might require specialized etching equipment, which not all PCB manufacturers can support. That’s why working with an experienced supplier like Best Technology is crucial.

How to Choose the Right Copper Thickness for Your PCB?

Rather than defaulting to the thickest copper available, consider these design factors:

  • Power Dissipation

Estimate total wattage and heat output. Use simulation tools or thermal imaging to understand hot zones.

  • Current Capacity

Follow IPC-2152 guidelines to determine trace width vs. amp load. For example:

1 oz copper: ~10A for 100 mil trace (surface)

2 oz copper: ~18A for same width

  • Board Size and Layer Count

Larger boards may use thinner copper with thermal vias and heat sinks. Multilayer designs must balance all layers.

  • Application Environment

Will the board be exposed to vibration, moisture, or rapid temperature swings? If yes, go thicker and stronger.

  • Budget and Lead Time

Thick copper PCBs cost more and take longer to fabricate. Optimize design for performance within your price range.

Rule of thumb:

  • Use 1 oz–2 oz copper for LED lighting, chargers, and automotive control boards.
  • Go for 3 oz–4 oz only if you have continuous high current or extreme heat.
  • Consider 5 oz+ only for industrial power systems or heavy-duty applications.

Case Study: How Thicker Copper Solved and Created Problems

A client building a 500W motor driver switched from 2 oz to 5 oz copper core PCB to improve thermal dissipation. While heat decreased by 12%, they faced new issues:

  • Via drilling became inconsistent due to copper pull-out.
  • Board warpage increased after reflow soldering.
  • Assembly cost rose by 30%.

We helped them optimize with a hybrid solution:

  • Kept 2 oz on signal layers.
  • Added localized copper in power zones.
  • Improved base layer contact for better heat flow.

Finally, thermal performance remained strong, but manufacturability and cost were brought back under control.

How to Choose Suitable Copper Thickness?

Conclusion

When designing a copper core PCB, it’s easy to fall into the trap of thinking ā€œthicker is better.ā€ In reality, optimal performance comes from careful engineering—not just stacking on copper.

At Best Technology, we help clients worldwide balance copper thickness with thermal, mechanical, and manufacturing constraints. We use simulation, prototype validation, and DFM support to ensure your final product is both high-performing and cost-effective.

Why Work With Best Technology for Copper Core PCBs?

We are not just PCB fabricators—we are problem solvers. Our copper core PCB services include:

✔️ Copper thickness options from 1 oz to 10 oz

✔️ Full-stack DFM analysis and thermal modeling

✔️ IPC-compliant thermal and electrical simulations

✔️ MES-based quality traceability

✔️ Rapid prototyping and scalable mass production

We help you avoid over-designing or under-designing copper thickness—saving cost and ensuring long-term reliability. No matter the application—EVs, LEDs, telecom, or industrial—you’ll find the right copper balance with us.

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FAQs

Q1: Is 3 oz copper enough for a 100W LED module?

Yes, in most cases 3 oz copper on a properly designed copper core PCB can handle that heat load efficiently.

Q2: How does copper thickness affect signal integrity?

Thicker copper affects impedance. It must be calculated carefully for high-speed or RF circuits.

Q3: Can thick copper cause warping during reflow?

Yes. Uneven copper thickness across layers can cause thermal imbalance. This must be addressed in stack-up design.

Q4: What’s better: thicker copper or more thermal vias?

Depends. Thermal vias can be more efficient in some layouts and cost less than increasing copper.

Q5: Does Best Technology support custom stack-ups for copper PCBs?

Absolutely. We provide custom stack-up planning based on your power, thermal, and mechanical needs.