PWB technology approaches: subtractive and additive technologies

 

There are two main types of manufacturing technologies of PWBs.

The subtractive technology uses copper clad laminates and subtracts the unnecessary pattern of copper layer from the surface by etching. In the course of the additive technology the wiring pattern is deposited physically, chemically or mechanically onto the originally insulating surface of the board. There is also a combination of the two processes, the semi-additive process.

 

Main characteristics of PWB technology approaches

 

Comparison of subtractive and additive PWB technologies

 

The subtractive manufacturing process is the most popular. Its main advantage is the excellent adhesion of the copper foil to the insulating board. The additive process is typical for thick film technology using ceramic substrates.

The variations of manufacturing routes to progress from a sheet of copper clad laminate to PWBs through different types of masking methods, etching and deposition techniques are numerous. In the followings the mostly characteristic sequences are discussed only.