PCB prototyping is a critical stage in electronics development, involving the creation of small-batch, functional circuit boards to test design concepts, validate performance, and identify potential issues before mass production. This process balances precision with flexibility, allowing engineers to iterate quickly and refine designs. The prototyping process typically begins with design file preparation, where Gerber files (or ODB++ formats) are generated from CAD software, specifying layer patterns, drill holes, and solder masks. Manufacturers review these files for manufacturability, checking for design rule violations such as minimum trace width, spacing, or via size.

Once the design is approved, the fabrication process starts with substrate preparation, using materials like FR-4 (a glass-reinforced epoxy resin) for standard prototypes or specialized materials (e.g., polyimide) for high-temperature applications. The substrate is coated with a photosensitive resist, which is exposed to UV light through a photomask containing the circuit pattern. The unexposed resist is then developed away, leaving the desired circuit pattern protected. Etching follows, where acid or plasma removes the unprotected copper, revealing the circuit traces.

After etching, drilling creates holes for vias and component leads, using mechanical or laser drills depending on hole size. The holes are then plated with copper to establish electrical connections between layers. Solder mask application—typically a green, blue, or black polymer—covers the board, leaving only pads and connectors exposed to prevent short circuits. Silkscreen printing adds component labels and reference marks for assembly. Finally, the prototype boards undergo testing, including continuity checks, insulation resistance tests, and functional testing with mounted components. PCB prototyping ensures that designs are feasible, reliable, and ready for scaling to mass production, reducing the risk of costly errors in later stages.