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PETER BRATIN, GENE CHALYT & MICHAEL PAVLOV, ECI Technology, East Rutherford, NJ, USA

ABSTRACT

Anew generation of online analysers of Damascene copper deposition plating solutions based on cyclic voltammetric stripping (CVS) can provide substantial yield improvements. The tight process window typically required for void-free filing of submicrometre high aspect ratio structures makes it important that additives be kept within a tight range. This problem has been addressed by new online analytical systems that sample plating tanks on a regular basis and determine the rate at which chemicals in the plating tool need to be replenished. The instrument sends a signal to the plating tool or dosing unit that automatically delivers the required additive components. The result is a closed loop system that maintains the process window within the strict limits required for high-yield Damascene plating.