Using a `Z' Tool Controller for APC Applications

Advanced process control (APC) has been shown to improve the performance to spec limits at critical process step(s) like chemical mechanical polishing (CMP) for the 130 nm node. Newer technology nodes are requiring APC applications at additional processing steps and processing equipment just to meet the spec limits. This is very apparent at the 90 nm. Traditional APC engines leverage metrology data in a manner that does not decouple the dataset between the tool controller and the device controller. A novel approach to orthogonalizing the data has been developed by leveraging a normalized "Z" statistic as the tool controller in conjunction with a uniquely developed device controller. The "Z" statistic is not new by any means. However, the use of it in conjunction with this unique device controller is new. The performance to spec has been shown to be impervious to tool perturbations and normal maintenance events while accommodating many reticles and several new product introductions.