What is the difference between positive film and negative film in PCB manufacturing
Negative film of PCB circuit board: It is generally the tenting process we talk about.The chemical solution used is an acid etching negative film because after the negative film is produced, the desired circuit or copper surface is transparent, and the unnecessary part is black. After exposure through the circuit process, the transparent part is chemically hardened due to the exposure of the dry film resist to light.The subsequent development process will wash away the unhardened dry film, so only the dry film washout is bitten during the etching process Part of the copper foil (the black part of the negative), and the dry film is not washed out. It belongs to the line we want (the transparent part of the negative).
