Application of CMP process monitor to Cu polishing

We have developed a chemical mechanical polishing (CMP) process monitor which uses polishing vibration. The monitor enables us to accurately detect the polishing end point in copper (Cu) polishing even when the process conditions such as initial film thickness, slurry flow and polishing rate are changed and when polishing multilayer film. Furthermore, the monitor is not only applicable to Cu polishing but also to planarizing polishing of an inter-level dielectric layer. The monitor can be also used to control the processes and the equipment because of its capability to detect abnormalities in the polishing conditions.