PCB Etching Process
While making PCBs, a layer of copper is added on the substrate. Sometimes, both the sides of the substrate are covered with copper layers. PCB etching process is carried out to get rid of the excessive copper, and only the required copper traces are left behind after the etching process.
The etching process can be carried out in a number of ways. However, the most commonly used method for etching is by using hydrochloric acid or ferric chloride. Both the chemicals are plentiful and economical.The main purpose of the PCB etching process is to trace the circuit design on a copper plate. To do this, there are several steps that you need to follow, which are as follows:
Step 1: The very first step of the etching process is designing the circuit, using the software of your choice. Once the design is ready, flip it, and then get it printed.
Step 2:On the transfer paper, print the circuit design. Make sure that the design is printed on the shiny side of the paper.
Step 3: Now, take the copper plate, and rub sand paper on it. This will make the surface of copper rough, and thus helps it to hold the design efficiently. There are certain points to remember step 3 till the last step:
- Use safety gloves, while handling copper plate and etching solution. This will prevent the oil from hands getting transferred to copper plate, and will also protect your hands from the solution or chemicals.
- When you are sanding the copper plate, make sure you do it properly especially at the edges of the plate.
Step 4: Now, wash the plate by some rubbing alcohol and water, so that any small particles of copper that get removed from the surface during sanding are washed off. Allow the plate to dry after washing.
Step 5: Cut the printed design properly, and place them on the copper plate facing down.
Step 6: The copper plate is now passed through the laminator several times until the plate gets heated.
Step 7: Take the plate out from the laminator, after it is hot, and hold it in a cold bath. Agitate the plate so that all the paper comes off and floats on the water. You will see a traced circuit in black on the copper plate.
Step 8: Now take the board out of the bath, and place it in the etching solution. Agitate the copper plate for around 30 minutes. Ensure that all the copper around the design is dissolved.
Step 9: Take out the copper plate and wash it in the water bath again. Keep it to dry. Once it has dried completely, you can use rubbing alcohol to remove the ink transferred to the printed circuit board.
Step 10: This completes the etching process of a printed circuit board. You can now drill the holes using proper tools with the required drill bit size.
