How do you choose the thickness of PCB copper?
Question
Register Now
top10pcb.com is a professional PCB Technical Platform. You can ask questions or post related articles by Registering and Logging In. Please note that if your question or articles are related to ad, they will be deleted.
Answer ( 1 )
Printed circuit boards consist of substrate and layers of copper foil. If the circuit board is one layer, the copper foil is only placed on top or bottom of the circuit board, and if the circuit board has two layers, the circuit board has copper foils on the top and bottom.
Typically, the thickness of the copper layers in copper weight is given as oz/ft ² but is usually only referred to as oz. However, sometimes the length is given in µm, with the relationship that 1 oz / ft2 corresponds to 17.5 µm.
Different thickness of the PCB copper layers
Typical values for the thickness of the copper layer are 0.5 oz, 1 oz, and 1.5 oz. This is the thickness of the base copper before any kind of metallization. When vias are made in the circuit board during the metallization process, the thickness of the copper layer typically increases to twice its initial value. For this reason, the typical thickness of the finished copper layers is 1 oz, 1.5 oz, and 3 oz. This increment always occurs in the outer copper layer. The outer layer is the top or bottom layer when it is single-layer and two-layer printed circuit boards, but also the outer layer when it is a multi-layer circuit board.
When manufacturing a multilayer board, the inner copper layers are referred to as inner copper layers, and in this case, the thickness is not increased since the metallization only affects the outer layers. This is perfectly true if you are working with vias where the multilayer is first created and the vias and metallization are done over the final stack. If blind or buried through-holes are required, these changes. The panels that have this type of through-hole must be drilled and metalized before assembling the final stack. In this case, the copper layer thickness of the inner layer can have the same value as the copper layer thickness of the outer layer.
It is very important to consider all of these aspects in order to determine the final thickness of your circuit board.
Applications of different copper layer thicknesses
Typical applications use the smaller copper thickness for various reasons. The important thing is the different chemical processes involved in removing copper to define the circuit in the substrate, and even during metallization, it is easy to get better traces if the copper thickness is less. As a result of these processes, it can be seen that the width of the track can be slightly different between the bottom and the upper end of the track, the lower part being wider. This effect increases with the thickness of the copper. For this reason, a copper base thickness of 0.5 oz is selected for RF applications in digital applications where the width of the conductor tracks is very important for good performance.
Thicker copper thicknesses are chosen for applications where the voltages, currents or RF power are higher. The high copper thickness helps to cope with the high temperatures that can arise from high currents or power. For this reason, 1 oz or 1.5 oz copper base thickness is used for high power amplifiers, batteries and power supplies where a lot of amps flow through the traces and a lot of heat energy needs to be dissipated. If a thin thickness is chosen, the track may burn. New challenging advances in power dissipation are the use of thicker copper layers up to 20 oz to improve performance.
In some RF applications, the choice of copper thickness can help improve performance, e.g. B. with filter parameters. When working with coupled lines, a thicker copper layer can improve the results compared to the thinner one.