ABSTRACT
Fig. 1. Many process components or byproducts can become contaminants on the wafer substrate. These contaminants may include abrasive particles (e.g., alumina, silica, ceria), polishing pad debris (e.g., polyurethane), materials removed by CMP from the substrate (e.g., particulate or dissolved metals, dielectric film debris) and chemical components (e.g., reducing or oxidizing agents, buffers, surfactants and other additives). All of these contaminants must be removed from the surface without damaging the underlying substrate before further processing can continue. Some substrate materials can be very sensitive to damage, especially some copper and low-K dielectric materials. Many process methods can be used for post-CMP cleaning, including chemical methods (e.g., etching, passivation and dispersion) and physical methods (e.g., contact brush scrubbing [2], energetic spray cleaning and ultrasonic/megasonic irradiation).
