| 摘要 |
PURPOSE:To prevent improper solder wettability, solder rise, corrosion of copper plating, or improper blow-hole by providing the step of removing a residue adhered to a printed wiring board by a plasma in a finishing step. CONSTITUTION:After a circuit is formed, it is covered with a photosolder resist film 3, fine residue 5 of the film 3 is presented on a conductor circuit 2 of both-side printed wiring board before finishing, and residue 6 of water content is presented in a through hole having 0.3mm of diameter. Such a board is set in a vacuum chamber, the chamber is evacuated in vacuum to 750mbarr or more, maintained under the pressure of 200mTorr with mixture gas of oxygen: fluorocarbon =3:1, high frequency power of 2.5kHz is applied to generate a plasma 7, treated in this state for 20 min, thereby removing the residue 5 on the circuit 2 and the residue 6 in the hole 4. Thus, it can solve improper solder wettability, solder rise, corrosion of Cu, and/or improper blow-hole. |
