Nickel-iron (80:20) alloy thin film electroplating method and electrochemical treatment and plating apparatus

A nickel-iron electroplating method for coating a substrate having a mask deposited thereon including means for electroplating nickel-iron alloy films containing about 20% iron onto a sheet substrate of a metallic material having said mask thereon,

• said method including employing a plating current density of about 2 - 60 ma/cm.sup.2,
• a plating bath fluid having an Fe.sup.++ ion concentration of about 0.3 g/l to about 0.7 g/l, an Ni.sup.++ ion concentration of about 17 - 44 g/l, a pH of about 1 - 3.6, and
• maintaining said bath at a temperature of about 20.degree. - 35.degree. C,
• wherein Fe.sup.++ ion concentration required for plating 20% iron is inverse to circulation of said plating bath fluid across said substrate.

A nickel-iron electroplating method including the process of electroplating nickel-iron films containing about 20% iron .+-. 1% onto a sheet substrate of a metallic material,

• said method including employing a plating current density of about 10 - 200 ma/cm.sup.2,
• a plating bath fluid with an Fe.sup.++ ion concentration of about 1.1 - 1.7 g/l, an Ni.sup.++ ion concentration of about 7 - 37 g/l, and a pH of about 1 - 3.6,
• and maintaining said fluid at a temperature of 20.degree. - 35.degree. C,
• wherein required Fe.sup.++ ion concentration required to produce said films with 20% iron .+-. 1% is an inverse function of circulation of bath fluid across said substrate.

A nickel-iron electroplating system including

• cell means for containing a plating bath fluid, an anode, and a cathode to be plated with a nickel-iron alloy comprising a constant percentage of iron,
• said cell including first and second vertical end walls,
• said cell including means for holding a wafer to be plated at the cathode of said cell with the surface to be plated supported facing the anode of said cell,
• a reciprocable mixer for agitation without substantial turbulence, supported by bearing means for providing longitudinal stirring action by reciprocation between said end walls cyclically, said mixer including a pair of confronting transverse blocks having a substantial slot therebetween and each having a symmetrical wedge shape with substantial opening between said blocks, said blocks having sharp edges facing the directions towards which said blade is adapted to reciprocate,
• an inlet to said cell in one of said end walls aligned with the surface of said cathode whereby said inlet is adapted to pass said plating bath fluid directly onto the surface of the cathode and through said slot,
• a reservoir for said plating bath fluid having an outlet connected by conduit means to said inlet, means for pumping said plating bath fluid up from said reservoir into said inlet via said conduit means,
• an outlet from said cell at an upper portion thereof high above the base of said cell having second conduit means for carrying said plating bath fluid into said reservoir,
• a thermostatic control, a temperature sensor and heating means connected to said reservoir for maintaining said reservoir substantially at 25.degree. C,
• a pH sensor and a dilute acid and an Fe.sup.++ ion dispenser for dispensing said acid and said Fe.sup.++ ion through a valve into said reservoir, and stirring means in said reservoir for maintaining a uniform temperature, and uniform values of pH, and Fe.sup.++ ion concentration and related conditions.