Devices and methods for in-situ control of mechanical or chemical-mechanical planarization of microelectronic-device substrate assemblies

The present invention relates to devices and methods for estimating selected parameters for controlling mechanical and/or chemical-mechanical planarization of microelectronic-device substrate assemblies. More particularly, the present invention relates to in-situ optical endpointing methods and devices. Planarizing machines and methods for endpointing or otherwise controlling mechanical and/or chemical-mechanical planarization of microelectronic-device substrates. In one embodiment of the invention, a method for planarizing a microelectronic substrate assembly includes removing material from the substrate assembly during a planarizing cycle by contacting the substrate assembly with a planarizing medium and moving the substrate assembly and/or the planarizing medium relative to each other. The method can also include controlling the planarizing cycle by predicting a thickness of an outer film over a first region on the substrate assembly and providing an estimate of an erosion rate ratio between the first region and a second region. The endpointing procedure continues by determining an estimated value of an output factor, such as a reflectance intensity from the substrate assembly, by modeling the output factor based upon the thickness of the outer film over the first region and the erosion rate ratio between the first region and the second region. The endpointing procedure continues by ascertaining an updated predicted thickness of the outer film over the first region by measuring an actual value of the output factor during the planarizing cycle without interrupting removal of material from the substrate, and then updating the predicted thickness of the outer film according to the actual value of the output factor and the estimated value of the output factor. The updated predicted thickness can be determined using an Extended Kalman Filter. The planarizing process is controlled according to the updated predicted thickness of the outer film.