Electroless copper deposition process having faster plating rates

Claim 1

In a method for electrolessly depositing copper from an electroless copper deposition solution which comprises copper ions, a complexing agent for copper ions, a reducing agent and a pH adjustor and which is characterized by a plating rate which first increases and passes through a peak plating rate and then decreases as a function of pH above 10, the improvement for depositing at a rate greater than about 7 micrometers of electroless copper per hour in a bath composition operated at a temperature of about 25° C. to about 35° C. to a rate greater than 19 micrometers of electroless copper per hour in a bath composition operated at a temperature above 35° C., a coherent, structurally stable thin film of electroless copper adherent to a substratum, comprising: (A) including within the electroless copper deposition solution an accelerating agent which contains a delocalized pi-bond and is selected from among (a) heterocyclic aromatic nitrogen and and sulfur compounds, (b) non-aromatic nitrogen compounds having at least one delocalized pi-bond, (c) aromatic amines, and (d) mixtures of any of the foregoing; (B) contacting the electroless copper deposition solution with a substratum sensitive to the deposition of electroless copper; and (C) while operating the electroless copper deposition solution at a pH above 10, regulating the pH thereabove and the amount of said accelerating agent therein to maintain a deposition within said rate, to thereby achieve a coherent, structurally stable thin film of electroless copper adhered to the surface of said substratum.

Claim 15

A method for depositing a coherent, structurally stable thin film of copper from an electroless copper deposition solution having a pH greater than 10 at a rate of between about 9 micrometers and 25 micrometers of electroless copper per hour in a bath composition operating at about 25° C. to about 35° C. to a rate greater than 19 micrometers of electroless copper per hour in a bath composition operated at a temperature above 35° C. which comprises including within the deposition solution an agent which produces depolarization of the anodic partial reaction of the solution or the cathodic partial reaction of the solution or both reactions, and while operating the solution at a pH above 10, regulating the pH thereabove and the amount of said agent so as to maintain the deposition at said rate.

Claim 16

A method for depositing a coherent, structurally stable thin film of copper from an electroless copper deposition solution having a pH greater than 10 at a rate of between about 9 micrometers and 25 micrometers of electroless copper per hour in a bath composition operating at about 25° C. to about 35° C. to a rate greater than 19 micrometers of electroless copper per hour in a bath composition operated at a temperature above 35° C. which comprises including within the deposition solution an agent which produces depolarization of the anodic partial reaction of the solution or the cathodic partial reaction of the solution or both reactions, and while operating the solution at a pH above 10, regulating the pH thereabove and the amount of said agent so as to maintain the deposition at said rate.