MONITORING AN ELECTROPOLISHING PROCESS IN INTEGRATED CIRCUIT FABRICATION

摘要

An electropolishing process of a metal layer formed on a wafer used in integrated circuit fabrication includes rotating the wafer. As the wafer is rotated, a stream of electrolyte is applied through a nozzle to the metal layer at a first radial location on the wafer. The electropolishing process is monitored by measuring electrical resistance at the first radial location. The electrical resistance measured at the first radial location is compared to a first preset electrical resistance associated with the first radial location. An electropolishing charge applied at the first radial location is controlled based on the comparison of the electrical resistance measured at the first radial location to the first preset electrical resistance associated with the first radial location. After applying the stream of electrolyte at the first radial location, the stream of electrolyte is applied at a second radial location. Electrical resistance at the second radial location is measured. The electrical resistance measured at the second radial location is compared to a second preset electrical resistance, which is different than the first preset electrical resistance, associated with the second radial location. The electropolishing charge applied at the second radial location is controlled based on the comparison of the electrical resistance measured at the second radial location to the second preset electrical resistance associated with the second radial location.