Electrochemical method for direct organic additives analysis in copper baths

A voltammetric method for measuring the concentration of an accelerator in a plating solution, comprising:

• cycling an inert working electrode potential through a metal deposition step and a metal stripping step, wherein the metal deposition step includes a constant voltage plateau at a potential of between about −0.25 V and about −0.4 V;
• determining a profile of an anodic current resulting from the inert working electrode potential as a function of time;
• determining a stripping peak area;
• and
• determining a concentration of the accelerator by a ratio of the stripping peak area from the profile of the anodic current to a stripping peak area of a base solution.

A voltammetric method for directly measuring the concentration of additives in a plating solution, comprising:

• cycling an inert working electrode potential through a metal deposition step, wherein the metal deposition step comprises scanning to a constant voltage plateau at a plateau potential sufficient to eliminate the interference of additives in the plating solution other than an additive to be measured and scasnning back to an open circuit potential from the plateau potential before the metal stripping step;
• cycling the inert working electrode potential through a metal stripping step, wherein the metal stripping step comprises an anodic linear sweep;
• determining a profile of the anodic current response resulting from the applied inert working electrode potential as a function of time;
• and
• determining the concentration of the additive to be measured by the anodic current response at the plateau potential.

A voltammetric method for directly measuring the concentration of an accelerator in a plating solution, comprising:

• providing the plating solution to an electroplating cell, wherein the electroplating solution includes copper sulfate in a ratio to an optimum copper sulfate concentration of between about 0.8 and about 1.2, and sulfuric acid in a ratio to an optimum sulfuric acid concentration of between about 0.8 to about 1.2;
• cycling an inert working electrode potential through a metal deposition step and a metal stripping step including an anodic linear sweep, wherein the metal deposition step includes pulsing to a constant voltage plateau at a plateau potential between about −0.25 V and about −0.4 V from an open circuit potential and pulsing back to the open circuit potential from the plateau potential before the metal stripping step;
• determining a profile of the anodic current response resulting from the applied inert working electrode potential as a function of time;
• and
• determining the concentration of the additive to be measured by a constant, kc determined from the current response when the plateau potential is between about −0.25 V and about −0.4 V.

A voltammetric method for measuring the concentration of an accelerator in a copper plating solution, comprising:

• cycling an inert working electrode potential through a metal deposition step and a metal stripping step, wherein the metal deposition step includes pulsing to a constant voltage potential from about −0.25 V to about −0.4 V from an open circuit potential and pulsing back to the open circuit potential before the metal stripping step, which comprises an anodic linear sweep;
• determining a profile of the anodic current resulting from the applied inert working electrode potential as a function of time and determining a stripping peak area;
• and
• determining the concentration of the accelerator by a ratio of the stripping peak area from the profile to a stripping peak area of a base solution not including the additive to be measured.