Method for potential controlled electroplating of fine patterns on semiconductor wafers

A method of electroplating a metal onto a surface comprising a field region and a plurality of recessed features, the recessed features having a range of sizes, the surface having a metal seed layer, the method comprising:

• contacting the surface with an electroplating solution comprising copper metal ions and at least one additive;
• applying a controlled first voltage to the surface for a time sufficient to provide a substantially conformal thin conductive layer on the recessed features, the first voltage being from about −10 millivolts to about −1000 millivolts with respect to a copper metal reference electrode disposed in a reference solution comprising copper metal ions but not the additive;
• applying a controlled second voltage to the surface, wherein the second voltage is larger than the first voltage, the second voltage controlled such that electroplating occurs preferentially on the bottoms of the recessed features, wherein the rate of electroplating is essentially independent of the number of recessed features, the size of the recessed features, and the distribution of the recessed features on the surface;
• and
• increasing said second voltage to a value providing a condition of rapid conformal plating.

A method of electroplating a metal onto a surface comprising a field region and a plurality of recessed features, the recessed features having a range of sizes, the surface having a metal seed layer, the method comprising:

• contacting the surface with an electroplating solution comprising copper metal ions and at least one additive;
• applying a controlled first voltage to the surface for a time sufficient to provide a substantially conformal thin conductive layer on the recessed features, the first voltage being varied from a value from about −5 millivolts to about −100 millivolts to a value from about −100 millivolts to about −500 millivolts with respect to a copper metal reference electrode disposed in a reference solution comprising copper metal ions but not the additive;
• applying a controlled second voltage to the surface, wherein the second voltage is larger than the first voltage, the second voltage controlled such that electroplating occurs preferentially on the bottoms of the recessed features, wherein the rate of electroplating is essentially independent of the number of recessed features, the size of the recessed features, and the distribution of the recessed features on the surface;
• and
• increasing said second voltage to a value providing a condition of rapid conformal plating.

A method of electroplating a metal onto a surface comprising a field region and a plurality of recessed features, the recessed features having a range of sizes, the surface having a metal seed layer, the method comprising:

• contacting the surface with an electroplating solution comprising copper metal ions and at least one additive;
• applying a controlled first voltage to the surface for a time sufficient to provide a substantially conformal thin conductive layer on the recessed features, the first voltage having a value sufficient to minimize dissolution of the seed layer;
• applying a controlled second voltage to the surface, wherein the second voltage is from about −50 millivolts to about −750 millivolts with respect to a copper metal reference electrode disposed in a reference solution comprising copper metal ions but not the additive, the second voltage controlled such that electroplating occurs preferentially on the bottoms of the recessed features, wherein the rate of electroplating is essentially independent of the number of recessed features, the size of the recessed features, and the distribution of the recessed features on the surface;
• and
• increasing said second voltage to a value providing a condition of rapid conformal plating.

A method of electroplating a metal onto a surface comprising a field region and a plurality of recessed features, the recessed features having a range of sizes, the surface having a metal seed layer, the method comprising:

• contacting the surface with an electroplating solution comprising copper metal ions and at least one additive;
• applying a controlled first voltage to the surface for a time sufficient to provide a substantially conformal thin conductive layer on the recessed features, the first voltage having a value sufficient to minimize dissolution of the seed layer;
• applying a controlled second voltage to the surface, wherein the second voltage is varied from a value of the first voltage to a value from about −100 millivolts to about −1000 millivolts with respect to a copper metal reference electrode disposed in a reference solution comprising copper metal ions but not the additive, the second voltage controlled such that electroplating occurs preferentially on the bottoms of the recessed features, wherein the rate of electroplating is essentially independent of the number of recessed features, the size of the recessed features, and the distribution of the recessed features on the surface;
• and
• increasing said second voltage to a value providing a condition of rapid conformal plating.

A method of electroplating a metal onto a surface comprising a field region and a plurality of recessed features, the recessed features having a range of sizes, the surface having a metal seed layer, the method comprising:

• contacting the surface with an electroplating solution comprising copper metal ions and at least one additive;
• applying a controlled first voltage to the surface for a time sufficient to provide a substantially conformal thin conductive layer on the recessed features, the first voltage having a value sufficient to minimize dissolution of the seed layer;
• applying a controlled second voltage to the surface, wherein the second voltage is from about −100 millivolts to about −1000 millivolts with respect to a copper metal reference electrode disposed in a reference solution comprising copper metal ions but not the additive, the second voltage controlled such that electroplating occurs preferentially on the bottoms of the recessed features, wherein the rate of electroplating is essentially independent of the number of recessed features, the size of the recessed features, and the distribution of the recessed features on the surface;
• and
• increasing said second voltage to a value providing a condition of rapid conformal plating.