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PCB Copper Thickness: Process, and Materials

Views: 933 Author: Site Editor Publish Time: 2023-04-24 Origin: Site

Width of copper on PCB

You are making a printed circuit board (PCB) and want to know how to figure out how thick the copper is. Copper width is essential to PCB design because it affects how well the board works, how reliable it is, and how much it costs. In this piece, we'll talk about how vital PCB copper thickness is and give tips for determining the best thickness for your PCB.

How thick is the copper on a PCB?

The thickness of the copper layer on the PCB is what is meant by "PCB copper thickness." Electroplating is used to add the copper layer to the base material. The thickness of the copper layer is generally measured in ounces (oz) per square foot (ft2), with a standard range of 0.5 oz to 6 oz.

Why is the thickness of copper on PCBs critical?

The copper layer on a PCB has several important jobs, such as connecting the components electrically and making a thermal path for heat to escape. The efficiency of the PCB is affected in several ways by how thick the copper layer is:

Resistance: The larger the copper layer, the lower the resistance. This makes it less likely that the voltage will drop and improves the quality of the signal.

• Thermal Conductivity: The thicker the copper layer, the better the thermal conductivity, which makes it easier for heat to escape and lowers the risk of overheating.

• Cost: The cost increases as the copper layer gets thicker because it takes more materials and costs more to make.

How thick is the copper usually on PCBs?

 PCBs usually have 1 oz of copper per square foot, the same as 1.4 mils or 35 microns. This width suits most PCB designs, even those with low power and speed.

How to Pick the Best Thickness of Copper for Your PCB?

The best copper thickness for your PCB relies on several things, such as how much power it needs, the frequency of its signals, how it will deal with heat, and how much it will cost. Here are some tips to help you figure out how thick the copper should be on your PCB:

• Low-Power and Low-Speed Designs: 1 oz of copper per square foot is enough for low-power and low-speed designs.

• High-Power Designs: For high-power designs, it's best to use a thicker copper layer to help heat move away and lower the risk of the circuit burning. Copper should have a thickness of at least 2 oz per square foot.

• High-frequency designs: To reduce the chance of signal loss and improve signal integrity, a thinner copper layer is suggested for high-frequency designs. Copper should have a thickness of 0.5 oz per square foot or less.

• Mixed-Signal Designs: A thicker copper layer is suggested to reduce the risk of crosstalk and interference in mixed-signal designs, where both analog and digital signals are used. Copper should have a thickness of at least 2 oz per square foot.

• Cost: PCBs with thicker copper layers cost more to make in terms of materials and labor. Consider the cost trade-offs when picking the best copper thickness for your design.

How does the thickness of the copper affect the trace width?

PCB Copper Thickness

 The PCB's trace width is affected by how thick the copper is. When the copper layer is thicker, the thickness of the traces can be made smaller, which makes the PCB smaller overall. But a thinner copper layer needs wider trace widths to carry the same power.

How does the thickness of copper affect the impedance of a PCB?

 PCB impedance, which is the resistance to the flow of electric data, is affected by how thick the copper is. A thicker copper layer lowers the impedance of the PCB, which improves the signal quality and makes it less likely that there will be noise or interference.

How does the thickness of the copper affect the making of PCBs?

The thickness of the copper affects how PCBs are made. Thicker copper layers take more time and higher currents to electroplate, which increases the time and cost of making.

How does the thickness of the copper affect the PCB assembly?

 The thickness of the copper changes how the PCB is put together. Soldering parts to the PCB can be more challenging if the copper layers are thick enough. Also, more immense copper layers can change how flat the PCB is, which can cause problems when putting it together.

How does the thickness of the copper affect the tolerances for making PCBs?

The limits for making PCBs depend on how thick the copper is. Manufacturing tolerances need to be tighter to keep the same level of accuracy and precision when making thicker copper layers. This can make the cost and time to make the product go up.

How does the amount of copper on a PCB affect its weight?

 The weight of the PCB depends on how thick the copper is. Thicker copper layers make the PCB heavier, which can be an issue when weight is significant.

How does the thickness of copper affect how flexible a PCB is?

The PCB's flexibility is affected by how thick the copper is. With more copper layers, the PCB is less flexible and stiffer. This is something to consider when the PCB needs to be bendable or flexible.

A PCB's thickness is an essential factor affecting its electrical and thermal features. This piece will discuss making PCBs the right thickness, including the materials and methods used.

Choosing What to Use

The first step in making a PCB is to choose suitable materials. A PCB usually has a layer of copper on top of a base material, such as FR-4. The width of the copper layer is essential because it determines how well the PCB can conduct electricity and heat. Copper is the best material for PCBs because it conducts electricity well, bends easily, and is easy to work with.

But to choose the right thickness of copper, you need to find a balance between efficiency and cost. The more copper there is, the better it conducts electricity and heat, but the more it costs. Most PCBs have a thickness of 1 oz (35 microns) of copper per square foot. A thicker copper layer, like 2 or 3 oz per square foot, may be needed for high-power applications or designs that need better thermal control.

Methods for Getting the Copper Thickness You Want

Electroplating and acid etching are the two main ways to get the copper thickness you want on a PCB. Each method has pros and cons, and the one you choose relies on the needs of the design and how much it will cost.

Electroplating

Electroplating is the most popular way to give a PCB the right amount of copper thickness. In this process, a layer of copper is put on top of the substrate material using an electric current. First, the base is cleaned and prepared to remove any dirt or other things that could hinder the electroplating process. After cleaning the material, it is put into a bath with a copper sulfate solution.

A bath is filled with a solution, and an electrode is put in it. The solution is then run through an electric current. The electric current draws copper ions in the solution to the base material. There, they form a layer of copper. The copper layer's thickness depends on how long the electroplating process takes and how strong the current is.

Electroplating is a very exact process that can be done repeatedly. This makes it perfect for mass production. It also makes making complicated shapes and designs possible because the copper layer can be put on only certain parts of the substrate material. But electroplating is more expensive than chemical etching because it needs special tools and skills.

Etching with chemicals

Chemical etching is another way to get the copper thickness you want on a PCB. Electroplating is first used to add a layer of copper to the base material in this process. The substrate is then covered with a film of photoresist, which is only exposed to light in certain places. The parts of the photoresist that are exposed to light get more complex, while those that aren't exposed to light stay soft.

The substrate material is then put into an etchant solution, which removes the copper in the photoresist material without light exposure. The photoresist material is then removed, leaving a layer of copper with the desired amount. Chemical etching is a process that is easy to do and doesn't cost much money. This makes it perfect for small production runs and prototypes. But it is not as accurate as electroplating, and the copper layer it makes may be a different thickness everywhere.

Conclusion

Ultimately, PCB copper width is an essential part of PCB design that affects how well the board works, how reliable it is, and how much it costs. Choosing the best copper thickness relies on a number of things, such as the amount of power needed, the signal frequency, how to handle the heat, and how much it will cost. By knowing how important the copper thickness of a PCB is and following best practices, you can create a PCB that is reliable, cost-effective and meets your needs.

About The Author

I am the Engineering and Sales supervisor working in Victorypcb from 2015. During the past years, I have been reponsible for all oversea exhibitions like USA(IPC Apex Expo), Europe(Munich Electronica) and Japan(Nepcon) etc. Our factory founded in 2005, now have 1521 clients all over the world and occupied very good reputation among them.

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