We can classify the production technology of PCB into 3 stages:
Initial Stage: From early twenties century to 1950s, it is ex-PCB production stage when the industry hasn't been developed to a formal one.
Developing Stage: From 1950s to 1990s, it is a period when PCB production technology is developing and been a formal industry
Expanding Stage: From 1990s to present. It is at the mid-stage of PCB industry.
Some typical PCB technology at this period is
At 1925, Charles Ducas of America proposed the idea to make groove at medium and fill with electrocondution slurry, then plate with copper to form a conductor.
At 1936, one Austrian Paul Ai Sile who lost his job at UK tested a foil membrane technology at radio. He applied a patent that using etching and cover soler mask to form a circuit during the period he work in Technograph which is a company invested by UK Henderson & Spalding. This PCB patent was published at 21st, June 1950 with three independent patents: GB639111(Core), GB639178 and GB639179.
At 1936, Japanese Miyamote Kinosuke applied patent about metal plating wiring with number 119384.
At 1938, fiberglass was make in production the first time.
At 1941, America started to use some PCB-like technology in military use--paint and copper paste on talc to make conducting wire for mortal.
At 1947, epoxy resin was introduced as a substrate
At 1947, NBS (National Bureau of Standards) of America started to research on coil, resistors and capacitors, etc.
At 1950, Japan started to use silver on glass substrate to make conductor and use copper foil on phenolic resin paper to make conductor
After 1950, the technology of Printed Circuit is widely accepted and used, main tech is etching foil.
As we look back, Charles Ducas and Miyamoto Kinosuke used semi-additive process, Paul Ai Sile used substractive process. As substractive process is more popular used and accepted, Paul Ai Sile is regarded as the father of PCB manufacturing. The American and Japanese giants made great contribution on PCB technology development objectively.