Xindaxing teaches you how to control the exposure energy of the board

Why do we want to control the exposure energy of printed circuit boards? Let's take a look.

 

Under ultraviolet light, the photoinitiator that absorbs light energy decomposes into free radicals to initiate photopolymerization, forming bulk molecules that are insoluble in the dilute alkali solution. In the absence of exposure, the film expands and softens during development due to incomplete polymerization, resulting in unclear or even detachment of the film, resulting in poor adhesion of the film to copper; if overexposed, development difficulties are caused. The board will also be plated. In this process, warp yarn peeling occurs and a plating layer is formed. Therefore, controlling the exposure energy is very important.