In-situ feedback system for localized CMP thickness control
 To attenuate a CMP polishing rate differential which tends to occur over the surface of a semiconductor substrate surface which has had one or more layers formed thereon, surface characteristics of the upper surface which are representative of the thickness, for example, of a layer which is being removed either in part or in its entirety, are monitored and surface profile information is developed using a suitable algorithm and used to control the timing with which force is applied by one or more of a plurality of actuators disposed on the other side of the wafer, in a manner wherein areas which have undergone more removal than others, are forced into contact with the polishing pad with a force which is reduced as compared that which is applied to localized high areas wherein a lesser amount of the layer has been removed. 
Advanced Micro Devices, Inc.
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Weizhong Jayendra D.
Wang Bhakta