Overlay and Semiconductor Process Control Using a Wafer Geometry Metric

摘要

The present invention may include acquiring a wafer shape value at a plurality of points of a wafer surface at a first and second process level, generating a wafer shape change value at each of the points, generating a set of slope of shape change values at each of the points, calculating a set of process tool correctables utilizing the generated set of slope of shape change values, generating a set of slope shape change residuals (SSCRs) by calculating a slope of shape change residual value at each of the points utilizing the set of process tool correctables, defining a plurality of metric analysis regions distributed across the surface, and then generating one or more residual slope shape change metrics for each metric analysis region based on one or more SSCRs within each metric analysis region.

主权项

1. A method for sorting wafers utilizing a slope of shape metric, comprising:
receiving a plurality of wafers; acquiring a set of wafer shape values from a surface of each wafer at a selected process level; generating a set of residual slope shape metrics for each wafer by calculating a residual slope shape metric at each of a plurality of points of each wafer; determining a neutral surface of each wafer in a chucked state; calculating a neutral surface factor (NSF) for each wafer utilizing the determined neutral surface for each wafer and a plurality of positions associated with a plurality of patterns of each wafer; determining a set of pattern placement error (PPE) residual values for each wafer, the PPE residual value for each point for each wafer being a product of at least the calculated NSF for each wafer, the residual slope shape metric for the point, and a thickness of the wafer; determining one or more thresholds for the set of residual shape metrics suitable for maintaining the set of PPE residuals below one or more selected levels; and characterizing the plurality of wafers by comparing the determined one or more thresholds for the set of residual shape metrics to the generated set of residual slope shape metrics for each wafer.