The mechanical pretreatment of printed circuit boards

In printed circuit board production a metallically pure surface has to be achieved or failure and rejection are unavoidable. Two kinds of cleaning are distinguished. The first is mechanical cleaning by abrasives. In the wet or the dry process, the wet process being predominant, removal of oxides proceeds at the same time as the surface structure is changed; in most cases roughening of the copper layer takes place. The second kind of cleaning is chemical. This also produces deoxidation and a change of surface structure. Depending on the solution used, the surface is scoured at the same time. Chemical processes (including electrochemical) are more expensive than mechanical processes and should only be weighed in the balance when mechanical processes are inapplicable.