Coalescent-jet apparatus and method for high current density preferential electroplating

Claim 1

Apparatus for the high current density electroplating of a recessed configuration within a metal substrate, comprising a. a housing member, which includes; i. a front face composed of an electrically non-conductive material, said front face having a number of ports, closely spaced and properly distributed for the discharge of electrolyte in the form of coalescent jets, ii. enclosure elements connected to said front face so as to form a substantially enclosed container, wherein one of said elements is fitted with inlet means for entrance of electrolyte into said housing, and iii. a non-consumable electrode, supported within said housing and spaced rearwardly from said front face, b. tank means for the storage of electrolyte, c. conduit and pump means for conducting electrolyte from the tank means to said housing member, said pump means being of sufficient power to urge the electrolyte through said ports with an impingement force sufficient to support said high current densities at the base of the recessed configuration, d. a source of electromotive force of sufficient voltage to effect said high current densities, the positive pole of which is in electrical connection with said non-consumable electrode, as anode, e. means connecting the negative pole of said electromotive source to said substrate, as cathode, f. means for maintaining said front face within a plating distance of less than three inches from said substrate, said housing ports being spaced and distributed so that, in the plane of said front face, (i) the maximum spacing between the edges of adjacent ports is less than said plating distance and (ii) the normal distance from the border B s around said recessed configuration to a border B h around said ports, is about 0.5 to 1.5 times said plating distance, and wherein the total cross-sectional area of the port openings is no greater than about four times the cross-sectional area of said inlet means, whereby the jets of electrolyte issuing from said front face are caused to coalesce prior to substantially perpendicular impingement onto said recessed configuration.