The origins of printed circuit board (PCB) manufacturing methods can be traced back to the early 20th century, with the core goal of simplifying electronic device assembly and reducing the complexity of traditional wiring. Early explorations involved engineers attempting to directly form conductive lines on insulating substrates, primarily employing two processes: additive and subtractive methods.
In 1925, American engineer Charles Ducas successfully printed circuit patterns on an insulating substrate and formed conductors through electroplating, marking an early application of the additive method—adding conductive material only where needed. Around the same time, Austrian Paul Eisler invented foil technology in Britain in 1936, employing a subtractive method: first, copper foil was applied to the substrate, then the excess was etched away, leaving the desired circuit pattern. These two methods laid the foundation for PCB manufacturing, with Eisler's subtractive method being more similar to modern PCB processes.
Early PCB substrates often used talc, phenolic resin, or glass fiber, with copper as the primary conductor. In the 1940s, PCB technology began to be used in military equipment, such as military radios, driving its standardization process. After the widespread adoption of transistors in the 1950s, PCBs were widely used due to their high reliability and low cost, and etching foil technology became the mainstream.