METHOD FOR METAL COATING HOLES IN MULTILAYER PRINTED-CIRCUIT BOARDS Russian patent published in 2012 - IPC H05K3/42 H05K3/46 

FIELD: chemistry.

SUBSTANCE: method for metal coating holes in multilayer printed-circuit boards involves deoiling and pickling the workpiece, treating said workpiece in a silver solution based on potassium ferrocyanide and potassium rhodanate, sensitisation in a tin chloride solution, activation in a palladium chloride solution, chemical copper plating, galvanic copper plating and thermodiffusion treatment in an argon medium while raising temperature in steps. Galvanic copper plating in pyrophosphate electrolyte at temperature of about 40°C and raising temperature in steps during thermodiffusion treatment in an argon medium are carried out in the following modes: (40±0.1)°C for 64930 s; (41±0.1)°C for 41956 s; (42±0.1)°C for 528 s; (43±0.1)°C for 260 s; (44±0.1)°C for 97 s; (45±0.1)°C for 52 s; (46±0.1)°C for 33 s; (47±0.1)°C for 16 s; (48±0.1)°C for 10 s; (49±0s1)°C for 7 s.

EFFECT: high reliability of interlayer connections in multilayer printed-circuit boards, shorter cycle for making printed-circuit boards and reduced labour input of the process.