Learn how to create PCBs in-house using UV photolithography, chemical etching, and fabrication

In-House PCB Fabrication: From Design to Etching

Creating your own PCBs in-house allows for rapid prototyping, cost savings, and full control over the manufacturing process. Here’s a concise guide to how it’s done:

Steps in PCB Fabrication

1. Design & Print

   • PCB layouts are designed using KiCad or other EDA tools.
   • Designs are printed on transparent acetate sheets to create a UV mask.

2. Photoresist Application

   • Copper-clad boards are coated with dry-film photoresist using a lamination machine.
   • Ensures uniform adhesion and bubble-free coverage.

3. UV Exposure

   • Boards are exposed to UV light through the printed mask.
   • The pattern transfers onto the photoresist, forming the circuit layout.

4. Development

   • Exposed boards are immersed in a developer solution (sodium carbonate) to dissolve unexposed photoresist.
   • The copper traces are revealed precisely according to the design.

5. Chemical Etching

   • Etching solution (HCl + H₂O₂) removes unwanted copper from the board.
   • Continuous monitoring ensures accurate pattern formation.

6. Finishing

   • Remaining photoresist is stripped using NaOH.
   • Holes are drilled, surfaces cleaned, and the PCB is ready for soldering components.

Materials & Tools

• Copper-clad FR4 boards, photoresist film, and acetate sheets
• UV exposure chamber, lamination machine, drill press
• Chemicals: developer, etchant, and stripper solutions
• Safety gear: gloves, goggles, ventilation

Insights

• Hands-on learning: Students get practical experience with PCB processes.
• Precision matters: Proper exposure, development, and etching times are critical.
• Safety first: Controlled chemical handling and PPE are essential for all steps.
• Rapid iteration: Design changes can be quickly tested without external fabrication delays.

Special thanks to Pramesh Aryal and Prashant Bhandari for their guidance and support in making this hands-on PCB fabrication experience possible. Your expertise and encouragement made the project smoother and more insightful.