The PCB allows all components to communicate with the system-on-chip (SOC) and other microchips via hundreds of copper wires. It consists of several conductive layers.

The top and bottom layers are used to mount components. They feature a layer of solder mask—usually blue or green—to provide insulation while keeping the part's mounting pads accessible.

There are also power and ground planes inside the PCB. The remaining copper layer carries any communication traces or signal lines. Epoxy and insulating fiberglass sit between these layers to prevent current from flowing.

When it comes to putting all these widgets together, robotics are the obvious choice. Here are the steps of a manufacturing process that relies on robotics:

1. Imaging and Development/Etching/Exfoliation (DES)

After people have designed the PCB, reviewed it, and printed it, it's time to start building the board. First, laser direct imaging started working on panels. The machine develops the dry film and etches any exposed panel copper. Then peel off the remaining dry film leaving the copper pattern behind which will be part of the inner layer.

2. Automated Optical Inspection (AOI)

This procedure is only applicable to multi-layer PCBs. AOI inspects the layers of a multilayer board before laminating them together. It does this by comparing the PCB design data with its image as viewed on the panel. This process is important because it allows manufacturers to notice and correct defects. For example, AOI might detect pinholes or tiny cuts in etched patterns.

3. Chemical treatment

Oxide chemicals treat the inner layers of multilayer PCBs prior to lamination. This increases the roughness of the copper clad, which will improve the bond strength of the laminate. It helps prevent layers from separating at the end of the manufacturing process.

4. Lamination

Many layers in a multilayer PCB must be bonded together. A hydraulic press uses high temperature and pressure to bond the conductive core with alternating layers of epoxy-infused fiberglass panels, causing them to fuse. After cooling, multilayer and double-sided PCB fabrication will follow the same process.

5. Drilling

Drilling holes is an important part of PCB design. They are used to mount PCBs in their housings and to connect components.

They also connect by allowing copper wires to run vertically through the board

Two or more layers. This process is called Vertical Interconnect Access (VIA). There are three types of VIA holes:

Via: Connects all layers of the PCB.

Blind Via: This type of hole connects the top or bottom layer to the middle layer.

Buried vias: Buried vias connect internal layers. This is the only kind of hole that is not connected to the top or bottom of the board.

Advanced precision drilling systems create these precise holes. They use solid carbide cutting tools designed for PCBs.

6. Electroless copper plating

The electroless plating process involves the chemical deposition of a thin layer of copper on all exposed surfaces of the PCB. The hole walls are also coated and can be electroplated. Copper coatings are very thin—between 80 and 100 millionths of an inch thick.

7. Dry film outer layer

A laminator applies a dry film to the outer layer of the copper panel. Then, laser direct imaging exposes it. While the unexposed film is being developed, the exposed film is left behind.

This process prepares the panel for electroplating.

8. Plating

During the electroplating process, machines electroplate copper onto the PCB's hole walls and conductive patterns. This step ensures that the design requirements of the circuit are met.

The PCB is connected to the cathode bar. The copper plating bath then uses a DC power source to apply current to deposit the copper plating onto the board. Next, the PCB goes into a tin plating bath where a coating is deposited on it. This will act as an etch barrier for the next step in the PCB manufacturing process.

9. Stripping and etching

The machine strips the resist board and the exposed copper not covered by tin is etched away. Next, the machine chemically strips the remaining tin covering the holes and traces.

10. Apply soldermask and legend

One machine uses liquid photoimaging (LPI) solder mask to protect copper surfaces. This photosensitive epoxy-based resist completely covers the panel, which goes through an adhesive cure cycle.

Film tools or laser direct imaging expose the panel to a UV light source. This process removes all unexposed solder mask. The oven bakes it to ensure that the solder mask hardens, cures, and adheres to the board.

Next, a screen printing process applies a legend, which consists of letters or symbols that serve as reference points during assembly.

11. Apply Surface Treatment

The machine applies the surface finish to the PCB through a chemical process. It prevents the remaining bare copper from oxidation.

12. Electrical test

A technician moves a PCB into a machine that tests its conductivity. It uses multiple moving probes to touch different points on a copper circuit and send electrical signals between them. This identifies shorts and opens.

13. Manufacturing

A CNC machine takes each board out of the larger panel and forms it to the desired size and shape. It also cuts grooves and bevels.

14. Check

Technicians and machines inspect the final product to catch any errors before shipping. This is critical when evaluating PCBs used in flight control systems or medical equipment.

Anyone with a smartphone has benefited from the use of robotics. While PCB manufacturing is technically possible without automation, it would be a slow, laborious process with little output. Machinery allows for speed, consistency, and extreme precision in the manufacture of smaller, more powerful printed circuit boards. Thanks to robotics, the world is more connected than ever.