| US 7,468,322 B1 | ||
| Methods of multi-step electrochemical mechanical planarization of Cu | ||
| Vishwas Hardikar, Tempe, Ariz. (US) | ||
| Assigned to Novellus Systems, Inc., San Jose, Calif. (US) | ||
| Filed on Apr. 26, 2005, as Appl. No. 11/115,520. | ||
| Int. Cl. H01L 21/302 (2006.01) | ||
| U.S. Cl. 438—690 [216/38] | 31 Claims |
| 1. A method of using an electrochemical planarization composition for removing material from a wafer having an exposed bulk
layer and a surface, the method comprising:
applying a first current to the wafer at a current density within a range of between about 5 mA/cm2 and about 20 mA/cm2 for a time duration suitable to remove a first portion of the bulk layer to thereby planarize the wafer surface; and
after the step of applying, administering a second current to the wafer at a current density within a range of between about
20 mA/cm2 and about 40 mA/cm2 to the wafer for a time duration suitable to remove a second portion of the bulk layer so that a third portion of the bulk
layer having a predetermined thickness remains, wherein the second current is greater than the first current;
wherein the electrochemical planarization composition is formulated to planarize a high topography and a low topography of
the wafer while a current is supplied to the wafer at a current density within a range of between about 5 mA/cm2 and about 40 mA/cm2.
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