PROCESS OF METAL SPRAYING OF HOLES OF PRINTED CIRCUIT BOARDS Russian patent published in 1995 - IPC

FIELD: radio engineering. SUBSTANCE: workstock of printed circuit board with holes is treated in aqueous solution of base in which capacity aqueous solution of ammonia with concentration 5-20 per cent by mass or monoethanolamine with concentration 3-25 per cent by mass in solution or their mixture with mass proportion of ammonia and monoethanolamine 0.2-0.3 in solution and total concentration of mixture 3-25 per cent by mass are used. Treatment is conducted for 0.5-5.0 min. Then workstock is treated in solution of chemical metallization including phosphorus-containing salt of copper. Ammonia with its concentration 3-25 per cent by mass in solution or monoethanolamine with concentration 10-40 per cent by mass or their mixture with mass proportion of ammonia and monoethanolamine 0.1-2.5 and total concentration of mixture 3-40 per cent by mass are used as base in solution of chemical metallization. EFFECT: increased output of good printed circuit boards.