Application of Real-Time Cu Thickness Profile Control in Cu CMP

In this paper, a real-time profile control (RTPC) system in Cu CMP is introduced. The system mainly contains two parts: 1). Real-time metal thickness monitoring based on electromagnetic induction of eddy current in conductive metal layer; 2). Real-time new polishing pressure computing and adjusting for desired metal thickness profile. The RTPC system has been applied in bulk Cu removal step of Cu CMP. The result showed that the Cu thickness profile after bulk Cu removal was flatter and its WIW uniformity was improved by greater than 35% while WTW uniformity could be improved by greater than 65%.