Knowledge Base

PCB etching – what is it and why etching is so important?

The PCB etching process for a long time is considered a complex yet essential step in producing printed circuit boards.

The etching process is done by applying multiple chemicals over the printed circuit board, thus called “PCB etching.”

The etching is done to remove a thin layer from the PCB copper board to expose the circuit’s embedded patterns in the copper. Once the etching process is done, the PCB can be applied with a solder mask that will give it an additional protective layer.

In this article, we will cover everything about the etching process. Why is it so important? How to do it? The benefits of the process and, most notably, how you can do it by yourself at home. If you are looking for a PCB etching solution, you have come to the right place. Let’s get started!

pcb electroplating etching

What is needed for PCB etching

A layout file is required for a PCB factory to start etching the printed circuit board. Layout files can easily be generated using PCB design CAD software. Once the files are prepared, the factory can insert them into a designated program to determine what copper parts should be etched to expose the circuit lines. In most PCB factories, this process is done automatically and doesn’t require intervention.

The benefits of etching a PCB

PCB etching is a must, and it’s not a decision if to do it or not. The process itself holds many benefits compared to other PCB and PCBA processes in terms of efficiency and cost:

  • 1. There is no minimum quantity – the quantity is based on the amount of PCBs fabricated.
  • 2. There are multiple ways to do etching (wet etching and dry etching). Both PCB etching methods give the same results. However, we can control the cost, speed, and ability to produce high-quality PCB boards by having multiple options.
  • 3. Unlike many other procedures, DIY etching can be done at home without needing expensive and heavy equipment.

pcb inner layer etching

Types of PCB etching

PCB etching falls into two main categories: Dry etching and wet etching. Below is the explanation of each of the methods

Dry etching

The dry process is considered quite popular in extensive PCB production facilities. However, in homemade DIY conditions, it’s not easy to accomplish.

This type of process involves plasma. When it points at the right spots of the copper board, certain parts of the copper will dissolve. By dissolving them, we can expose the circuits that we want.

Although we mentioned that this process is done using plasma, the identical PCB etch can be accomplished using lasers. The decision on etching technology is based on the board design and project requirements.

Wet etching

The wet etching manufacturing procedure is done using chemicals. “Wet” means soaking the copper in chemicals to dissolve the copper board. This process is often used in DIY etching because it is low cost and doesn’t require heavy-duty equipment.

Different printed circuit boards come in various types of materials. Based on the printed circuit board, an acidic or alkaline solution will be chosen for the wet PCB etching process. Other types of materials need a different chemical solution to dissolve.

Nevertheless, both etching solutions will bring the same expected results.

PCB etching

When is PCB etching done?

The PCB etching is done at the final stage of the PCB manufacturing procedure. The only location after the etching process would be applying the solder mask. The solder mask is used as a thin protective layer. Once the etching is done, the circuit board is technically ready to use.

DIY circuit board etching

DIY etching can be risky and unsafe if you don’t know what you are doing. However, if you are an experienced engineer, DIY etching could save you a lot of time. The self-etching process usually involves the following steps:

  1. Prepare the layout PCB design files.
  2. Make sure you use a laser printer. Print the layout on top of a transparent plastic sheet (often called OHP) using a laser printer. Other printers won’t work.
  3. The third stage is called “Toner transfer.” This stage is done by placing the sheet on top of a copper board and heating it.
  4. Soak the transferred PCB board into a wet etching solution. This kind of solution is made using 40% chloride.

Once the fourth stage is successfully accomplished, you should have a beautifully finished DIY etched PCB.

Once the PCB is etched, it’s recommended to apply a solder mask in order to protect the board. If any drilling is necessary, it can be done once the solder mask has been applied.

DIY etching cautions

The chemical used in the printed circuit board etching process contains highly corrosive materials. Using chemicals by yourself can be pretty dangerous. Always ensure to wear gloves, a face mask, and eye protection gear.

There are certain risks you should always be aware of when dealing with PCB etching on your own:

  • 1. When dealing with chemicals, there is always a risk of accidentally getting injured, even when wearing protection.
  • 2. Etching at home and using a certified PCB factory will yield different results. While etching at home is fun to try an experiment, it is not suitable for mass production. The quality might be different than expected.
  • 3. When dealing with such chemicals, leftover materials will be disposed of. Those materials can’t be thrown in the trash, they need to be disposed of safely.

PCB etching summary

We learned a lot about the etching process: What is etching, how to etch a PCB, how to DIY etch a PCB, the benefits and dangers of the process, etc.

DIY etching at home is helpful, fast, and cheap. However, it holds many dangers and is not a process recommended for mass production.

If you are looking for a reliable PCB factory to produce, etch and test your brand new PCB design, PCBasic is here for you.

We specialize in small-batch PCB and PCBA including prototyping and mass production. Whatever your size or project needs, we can assure you that using our services will be cheaper, better, and faster than etching a PCB by yourself.