Patent ID: 7371311
Filing Date: 2008-05-13
Classification: C25D

Abstract:
1. A method comprising: determining a concentration of a conductive metal and of an acid for a low-acid electroplating solution; determining a concentration of a leveler for the low-acid electroplating solution based upon the concentration of the conductive metal and the acid only after determining the concentration of the conductive metal and the acid such that the leveler concentration is sufficient to reduce a within die thickness variation to a specification value; and determining a concentration of a suppressor for the low-acid electroplating solution based upon the concentration of leveler only after determining the concentration of the leveler such that the concentration of the suppressor is sufficient to substantially reduce a number of electroplating defects while maintaining the within die thickness variation below the specification value; evaluating the benefits of reducing the within die thickness variation with the detriments of increased defects when the concentration of the suppressor is increased, the concentration of the leveler and the suppressor are determined as maximum that effect a proper gap fill of a semiconductor wafer; determining a concentration of a chloride for the low-acid electroplating solution such that the chloride concentration is sufficient to catalyze the suppressor, the concentration of the chloride determined as a minimum to catalyze the suppressor to provide the proper gap fill, the concentration of the chloride based on a feature size and an aspect ratio of the semiconductor wafer; and determining a concentration of an accelerator for the low-acid electroplating solution based upon the leveler concentration and the suppressor concentration only after determining the concentration of the suppressor and of the leveler, the concentration of the accelerator reduced to allow a maximum concentration of leveler and suppressor, the concentration of the accelerator based on the feature size and the aspect ratio of the semiconductor wafer, wherein the concentration of the leveler is at least about 12 ml/l.