PCB design and manufacturing

A printed circuit board (PCB) mechanically supports electronic components and connects them electrically through conductive copper tracks formed on an insulating substrate. Design begins with a schematic that captures the circuit, which is then turned into a physical layout: components are placed and the copper tracks, called traces, are routed between them. Boards may have copper on one side, on both sides, or on several internal layers separated by insulating material, allowing complex circuits to be packed into a small area.

Manufacturing converts the layout into a real board. A copper-clad laminate is patterned so that the wanted traces remain while the unwanted copper is removed, typically by an etching process that chemically dissolves the exposed copper. Holes are drilled for connections and components, plated to join layers, and the board is finished with a solder mask and printed markings. The result is a rigid, repeatable interconnection that replaces hand wiring.

Components are then attached during assembly. Older through-hole parts have leads pushed through drilled holes and soldered on the far side, while surface-mount technology (SMT) places much smaller surface-mount devices (SMDs) directly onto pads on the board surface. Automated assembly systems apply solder paste, position the parts and reflow the solder in an oven. Soldering practice has shifted toward lead-free alloys for environmental reasons, which changed the temperatures and techniques used in modern production.

Frequently asked questions

What is etching in PCB manufacture?

Etching chemically removes the unwanted copper from a copper-clad board, leaving behind only the conductive traces that form the circuit's wiring.

How does surface-mount differ from through-hole assembly?

Through-hole parts have leads inserted into drilled holes and soldered on the other side, while surface-mount devices are soldered directly onto pads on the board surface, allowing smaller, denser, more automated assembly.

Why has lead-free soldering become common?

Environmental regulations encouraged the move away from lead-containing solder. Lead-free alloys generally melt at higher temperatures, which altered soldering profiles and techniques.