Method and apparatus for process endpoint prediction based on actual thickness measurements

摘要

In accordance with one aspect of the present invention, a method is provided for predicting the endpoint time of a semiconductor process for a layer of a wafer (14). The endpoint time is the time at which a predetermined thickness of the layer occurs. A layer thickness, calculated for a first sample time, is received. It is then determined whether or not the layer thickness lies within a predetermined range. If the layer thickness does lie within the predetermined range, it is used to update a forecasted process rate. The forecasted process rate is used to predict the endpoint time. The endpoint time is used to control the semiconductor process so that the layer of wafer (14) is formed having the predetermined thickness.