The History of Printed Circuit Board Assembly

In 1941, the United States applied copper paste onto talc substrates to create wiring for the production of proximity fuses.
In 1943, the United States began utilizing this technology extensively in military radio equipment.
In 1947, epoxy resin began to be used in the manufacture of substrate materials. Concurrently, the National Bureau of Standards (NBS) initiated research into manufacturing techniques for forming components-such as coils, capacitors, and resistors-using printed circuit technology.
In 1948, the United States officially authorized the commercial use of this invention.
Beginning in the 1950s, transistors-which generated significantly less heat-began to largely displace vacuum tubes; it was at this juncture that printed circuit board technology began to gain widespread adoption. During this period, the etching of foil laminates emerged as the dominant manufacturing technique.
In 1950, Japan began utilizing silver paint for wiring on glass substrates, as well as copper foil for wiring on paper-based phenolic substrates (Copper-Clad Laminates, or CCLs) made from phenolic resin.
In 1951, the advent of polyimide resin marked a significant advancement in the heat resistance of substrate materials, leading to the subsequent development of polyimide-based circuit boards.
In 1953, Motorola developed a double-sided printed circuit board utilizing the plated-through-hole (PTH) technique. This method was subsequently applied to the production of multi-layer circuit boards.
By the 1960s-a decade after their initial widespread adoption-printed circuit board technologies had reached a stage of increasing maturity. Following the introduction of Motorola's double-sided boards, multi-layer printed circuit boards began to emerge, thereby significantly improving the ratio of wiring density to substrate surface area.
In 1960, V. Dahlgreen created the first flexible printed circuit board by embedding a metal foil imprinted with a circuit pattern into a thermoplastic substrate.
In 1961, the Hazeltine Corporation in the United States developed a multi-layer circuit board by adapting the plated-through-hole technique.
In 1967, a manufacturing technique known as "Plated-up technology"-a form of additive processing-was introduced.
In 1969, FD-R successfully manufactured flexible printed circuit boards using polyimide resin.
In 1979, Pactel introduced the "Pactel process"-another innovative method within the field of additive circuit board manufacturing. In 1984, NTT developed the "Copper Polyimide Method" for thin-film circuits.
In 1988, Siemens developed a build-up printed circuit board for Microwiring Substrates.
In 1990, IBM developed the "Surface Laminar Circuit" (SLC) build-up printed circuit board.
In 1995, Panasonic developed the ALIVH build-up printed circuit board.
In 1996, Toshiba developed the B2it build-up printed circuit board.