How Thick Is Standard 1oz Copper Thickness?

In the world of Printed Circuit Boards (PCBs), 1oz Copper thickness plays a crucial role in determining the performance and functionality of the board. 

Copper is often used in PCBs because it conducts electricity and heats well. But the thickness of the copper can change depending on the project. This article will look at the standard 1oz copper thickness in PCBs and why it matters for manufacturing.

In this article,

• Understanding the Standard Copper Thickness
• Advantages and Disadvantages of Standard 1oz Copper Thickness
• Comparison with Other Thicknesses of Copper
• Factors Affecting 1oz Copper Thickness in PCB
• Determine the Right 1oz Copper Thickness for Your PCB
• Comparison Between Different Copper Thicknesses

Understanding the Standard Copper Thickness

The standard copper thickness in PCB (Printed Circuit Board) refers to the thickness of the copper layer that is used to create the electrical connections on the board. Copper is an excellent conductor of electricity, and it is the primary material used for this purpose. '1oz copper thickness' means the thickness of copper on a PCB.

The measurement is carried out in ounces per square foot. When we say '1oz copper thickness', it means there is one ounce of copper on every square foot of the board.

It is important to note that the copper thickness of a PCB can affect the overall performance and reliability of the board. Proper selection and specification of the copper thickness should take into account the intended use of the PCB and any specific requirements or constraints that may be present.

Advantages and Disadvantages of Standard 1oz Copper Thickness

Advantages of Standard 1oz Copper Thickness in PCB:

• Excellent conductivity: Copper is an excellent conductor of electricity and provides low resistance to the flow of current. The 1oz copper thickness is sufficient to handle most applications, ensuring reliable and efficient performance. 
• Cost-effective: 1oz copper thickness is relatively inexpensive compared to other materials such as gold or silver, making it a cost-effective choice for PCB manufacturing.
• Wide availability: Copper is widely available, and the 1oz copper thickness is a standard option in most PCB fabrication processes.
• Adequate for low-power applications: 1oz copper thickness is adequate for low-power applications such as consumer electronics, where the current is relatively low.

Disadvantages of Standard 1oz Copper Thickness in PCB:

•  Inadequate for high-power applications:
  The 1oz copper thickness is commonly used in most PCBs as it provides good conductivity and durability for regular electronic applications. However, in high-power applications, the current is high, and heat dissipation is a concern. In such cases, a thicker copper layer or alternative materials may be required to address the issue. This is because thicker copper layers can handle higher current loads and provide better thermal conductivity to dissipate the heat generated by high-power components.
• Limited flexibility:
  1oz copper thickness has limited flexibility compared to other materials such as flexible PCBs or materials like polyimide. This makes it difficult to bend or shape the PCB in complex designs. This can be a significant constraint for designs where the PCB needs to fit into a specific form factor or where the board needs to be folded or bent.
• Vulnerable to corrosion:
  1oz copper thickness is vulnerable to corrosion over time due to environmental factors such as humidity, saltwater, and other contaminants. The copper layer can corrode and form an insulating layer on the surface, reducing the conductivity and overall performance of the PCB. To mitigate this, manufacturers may apply a layer of protective coating, such as a solder mask or conformal coating, to the surface of the PCB.

Comparison with Other Thicknesses of Copper

Here is a brief point-to-point explanation of how the thickness of copper in PCBs can be varied for different applications:

Thicker copper layers:

• Thicker copper layers are used in high-power applications that require more electrical current to flow through the board.
• These layers can be 2oz or 3oz in thickness, or even higher in some cases.
• The added thickness allows the board to handle more current without overheating or causing damage.
• High-power applications include things like power supplies, motor controllers, and LED lighting systems.

When to Use Thicker Copper?

In some cases, a thicker copper weight may be required for a PCB design. For example, if the board is designed to handle high current loads, a thicker copper weight may be necessary to prevent overheating and damage. Thicker copper can also help to reduce resistance and improve conductivity in certain applications. However, thicker copper also comes with a higher cost and may require more specialized manufacturing processes.

Thinner copper layers:

• For applications that demand greater accuracy and finer line widths, thinner copper layers are employed.
• These layers can be 0.5oz or 0.25oz in thickness, or even lower in some cases.
• Thinner layers allow for more precise control of the circuit board's electrical properties.
• These applications include things like mobile phones, tablets, and other small electronic devices that require precise control of electrical signals.

When to Use Thinner Copper?

Thinner copper may be used for designs that require smaller traces and spaces or for applications where weight is a concern. Thinner copper can also be used to reduce the overall cost of the board, as it requires less copper and can be etched more quickly. However, thinner copper may not be suitable for applications that require high current or conductivity.

Factors Affecting 1oz Copper Thickness in PCB

Trace Width:

The trace width is the width of the 1oz copper thickness conductor in a PCB.

The more 1oz copper thickness required to cover the trace, the thicker the copper layer will be, making the trace wider. Conversely, narrow traces require less copper, resulting in a thinner copper layer. For example, a 5-mil trace requires less copper than a 20-mil trace, resulting in a thinner copper layer for the former.

Current Carrying Capacity:

The amount of current a trace can carry depends on the trace's width and thickness. Thicker copper layers can carry more current without overheating or damaging the trace. As a result, high-current applications require thicker copper layers to avoid damage to the PCB.

Thermal Management:

Copper is good at carrying heat, and thicker layers help cool things down. When the circuit board requires high power, thicker copper is necessary to prevent overheating and breakdown.

Manufacturing Process:

The amount of copper on a PCB depends on how it's made. A process called electroplating adds copper to the surface using a tank. How long it's plated, how much solution is used, and how strong the current is, determine the thickness of the copper. Changing these things can create PCBs with different amounts of copper.

Cost:

Copper costs a lot, and using more of it makes things more expensive. So, when making a PCB, the amount of copper used depends on how well it needs to perform and how much it costs to make.

Determine the Right 1oz Copper Thickness for Your PCB

Current Requirements

The amount of current that a circuit needs to handle is one of the most critical factors in determining copper thickness. As the current increases, the resistance of the copper pathways also increases, leading to power losses and heat dissipation. Choosing thicker copper layers is preferable for high-power applications since they can sustain more current without overheating.

Thermal Management

Cooling is important in PCB design, especially for high-power devices. Bigger copper layers can help by giving more space for electrical paths and cooling. But, they can also make the PCB heavier and more expensive.

Signal Integrity

Copper thickness can mess up the circuit. It might bounce signals around and make them worse. If you want fast circuits, go for thinner copper to keep everything clear and precise.

Cost

1oz copper thickness can significantly impact the cost of the PCB. Thicker copper layers require more copper, which can increase the cost of the PCB. However, thinner copper layers may require more advanced manufacturing techniques and can also increase the cost of the PCB.

Current carrying capacity

The current-carrying capacity of a PCB is directly proportional to the 1oz copper thickness. If you expect the PCB to carry a higher current, you need to use a thicker copper layer. A 1oz copper thickness is ideal for a current range of 1-2A. If you want to increase the requirements, then it is advisable to opt for thicker copper layers. For instance, a 2oz copper thickness is ideal for a current range of 2-4A.

Comparison Between Different Copper Thicknesses

In the next part, we'll contrast regular 1oz copper thicknesses with other frequently utilized copper thicknesses in the industry. We'll check out how they affect the performance and reliability of the PCB.

2oz Copper in PCB: 

2oz copper in PCB means that the copper layer on the board has a thickness of 2 oz/ft², which is equal to 2.8 mils or 0.07112mm. It is twice as thick as the standard 1oz copper and provides a lower resistance path for high-current circuits.

Power supply circuits, motor control circuits, and other high-current carrying capacity applications commonly utilize them. However, it comes at a higher cost, and the increased thickness may affect the board's flexibility and manufacturability.

3oz Copper in PCB: 

3oz copper in PCB means that the copper layer on the board has a thickness of 3 oz/ft², which is equal to 4.2 mils or 0.10668mm. It is three times as thick as the standard 1oz copper and provides an even lower resistance path for high-current circuits.  

This actively powers devices that require high levels of energy, such as robust LED lights, RF amplifiers, and circuits that actively handle substantial electrical loads. But it costs more than regular copper and might need special ways of making it.

0.5oz Copper in PCB: 

0.5oz copper on a PCB means the copper layer is 0.5 ounces per square foot. That's about 0.7 mils thick or 0.01778mm. It's thinner than the usual 1oz copper and works well for low-power digital and RF circuits that don't need to carry as much current.

Conclusion

In conclusion, the thickness of standard 1oz copper in PCB is 1.4 mils or 35 microns. To ensure that the copper tracks on the PCB carry the required amount of current without overheating or getting damaged, it is essential to maintain a certain thickness.

In summary, the thickness of standard 1oz copper in PCB is a critical factor that affects the overall performance and functionality of the PCB. By understanding the importance of copper thickness and taking the necessary steps to ensure its accuracy, engineers can create robust and reliable PCBs that meet the needs of a wide range of applications.