Model-Based Hot Spot Monitoring

摘要

Methods and systems for monitoring parameters characterizing a set of hot spot structures fabricated at different locations on a semiconductor wafer are presented herein. The hot spot structures are device structures that exhibit sensitivity to process variations and give rise to limitations on permissible process variations that must be enforced to prevent device failures and low yield. A trained hot spot measurement model is employed to receive measurement data generated by one or more metrology systems at one or more metrology targets and directly determine values of one or more hot spot parameters. The hot spot measurement model is trained to establish a functional relationship between one or more characteristics of a hot spot structure under consideration and corresponding measurement data associated with measurements of at least one metrology target on the same wafer. A fabrication process parameter is adjusted based on the value of a measured hot spot parameter.

主权项

1. A measurement system comprising:
an illumination source configured to illuminate each of a plurality of metrology targets disposed a first plurality of locations on a wafer, the wafer also including a plurality of hot spot structures at a second plurality of locations on the wafer that are different from the first plurality of locations, the wafer being illuminated by the illumination source after an intermediate process step of a semiconductor wafer fabrication sequence; a detector configured to detect an amount of light from each of the plurality of metrology targets in response to the illuminating of each of the plurality of metrology targets and generate an amount of measurement data based on the detected amounts of light; and a computing system configured to: determine a value of at least one parameter characterizing a hot spot structure of the plurality of hot spot structures based on the amount of measurement data and a trained hot spot measurement model; and communicate a signal to a process tool that causes the process tool to adjust a process parameter associated with a fabrication process step of the semiconductor wafer fabrication sequence based on the value of the at least one parameter characterizing the hot spot structure.