Overlay error feedforward and feedback correction, root cause analysis and process control statistical overlay error prediction

摘要

The method to collect data and formulate, validate and deploy statistical models to predict overlay errors using patterned wafer geometry data and other relevant information selects a training wafer set. Measuring a number of lithography steps to calculate a geometric difference, applying a plurality of prediction models to the training wafer geometry difference, and comparing the prediction overlay to the measured overlay of the training wafer set. The most accurate predictive model is identified and the results are fed forward to a lithographic scanner, which can correct these effects and reduce overlay errors during the wafer scanning exposure process.