Removal of smear (organic residue)
Organic smear at the bottom of the via hole after laser processing is a problem in the build-up structure of a printed circuit board where one conductor layer is stacked one by one and interlayer connections are made with laser vias. Traditionally, it has been cleaned with chemicals such as permanganic acid. The photo shows the bottom of the via hole after plasma treatment with a plasma cleaning device. The smear has been removed and a roughened copper surface can be seen. The plasma cleaning system eliminates the need for chemical treatment and expensive ancillary equipment.