Review—Management of Copper Damascene Plating

Abstract

An overview of process and quality control issues faced in controlling copper damascene plating is provided. The challenges for effective management of a copper damascene plating process have evolved due to early limitations and problems which were discovered, and then as more demands resulted from Chemical Mechanical Planarization issues, yield and reliability concerns, reduction in critical feature size and the shift to 300 mm wafers as well as the adoption of dielectric films with low dielectric constants. The demands have been addressed by adherence to quality control methodology, improvements in plater design and operation, advancements in plating electrolytes, and by new metrology tools and methodology. The key measurement areas outlined here are bath concentrationmeasurement and control, film properties metrology, contamination issues, and defects. Particular attention is given to the use of electrochemical and optical methods with enhanced capabilities. This includes the use of chemometrics for electroanalytical bath concentration control and optical methods for film thickness, surface roughness, and film stress/wafer curvature measurements.