In-situ Cu layer thickness measurement during chemical mechanical planarization

In this paper, the eddy current method is used for measuring the thickness variation of Cu layer during chemical mechanical planarization (CMP) process. And an in-situ measurement system has been developed. A series of experiments have been done on the Universal-300 CMP system for evaluating the feasibility and reliability of the in-situ measurement system, and the accuracy of the system is presented. According to the experiment results, this technique can reach to nano-scale measurement and satisfies the in-situ measurement requirements. All the efforts are expected to further improve the in situ measurement technique, and ensure that the CMP system works efficiently.