Desmear processing method and manufacturing method for multilayer printed wiring board

Abstract

The purpose of the present invention is to provide a desmear processing method capable of sufficiently removing a smear while preventing the surface of a substrate from being rough. The desmear processing method according to the present invention is a desmear processing method for removing smear from a substrate in which a hole is formed, the desmear processing method comprising a first desmear processing step for dissolving and decomposing a part of the smear, and a second desmear processing step for performing ultrasonic treatment on the substrate after the first desmear processing step. Further, in the second desmear processing step, at least one of: changing the frequency of the ultrasonic waves; and moving an oscillation source of the ultrasonic waves and the substrate in two or more directions relatively to each other, is performed during the ultrasonic treating.

Dependencies are inferred from the claim text.