Virtual cross metrology-based modeling of semiconductor fabrication processes

A system comprising:

• a virtual cross metrology engine configured to:
• construct a given virtual metrology model configured to predict a wafer value for a given step of a semiconductor fabrication process, wherein the given virtual metrology model takes, as inputs, process parameters applied for the given step of the semiconductor fabrication process;
• construct a subsequent virtual metrology model configured to predict a wafer value for a subsequent step of the semiconductor fabrication process, wherein the subsequent step is performed after the given step in the semiconductor fabrication process, including by determining inputs for the subsequent virtual metrology model from a combination of:
• the process parameters applied for the given step of the semiconductor fabrication process;
• process parameters applied for the subsequent step of the semiconductor fabrication process;
• and
• the wafer value for the given step of the semiconductor fabrication process that the given virtual metrology model is configured to predict,
• wherein the virtual cross metrology engine is configured to determine the inputs for the subsequent virtual metrology model by determining a selected subset of the process parameters applied for the given step of the semiconductor fabrication process, the process parameters applied for the subsequent step of the semiconductor fabrication process, and the wafer value for the given step of the semiconductor fabrication process that the given virtual metrology model is configured to predict to use as the inputs for the subsequent virtual metrology model, and
• wherein the virtual cross metrology engine is configured to determine the selected subset by:
• performing a value analysis process on the process parameters applied for the given step of the semiconductor fabrication process, the process parameters applied for the subsequent step of the semiconductor fabrication process, and the wafer value for the given step of the semiconductor fabrication process that the given virtual metrology model is configured to predict in order to determine impact contributions to the wafer value predicted by the subsequent virtual metrology model for the subsequent step of the semiconductor fabrication process;
• and
• determining the selected subset based on the impact contributions determined through the value analysis process.

A non-transitory machine-readable medium comprising instructions that, when executed by a processor, cause a computing system to:

• construct a given virtual metrology model configured to predict a wafer value for a given step of a semiconductor fabrication process, wherein the given virtual metrology model takes, as inputs, process parameters applied for the given step of the semiconductor fabrication process;
• construct a subsequent virtual metrology model configured to predict a wafer value for a subsequent step of the semiconductor fabrication process, wherein the subsequent step is performed after the given step in the semiconductor fabrication process, and including by determining inputs for the subsequent virtual metrology model from a combination of:
• the process parameters applied for the given step of the semiconductor fabrication process;
• process parameters applied for the subsequent step of the semiconductor fabrication process;
• and
• the wafer value for the given step of the semiconductor fabrication process that the given virtual metrology model is configured to predict,
• wherein the instructions cause the computing system to determine the inputs for the subsequent virtual metrology model by determining a selected subset of the process parameters applied for the given step of the semiconductor fabrication process, the process parameters applied for the subsequent step of the semiconductor fabrication process, and the wafer value for the given step of the semiconductor fabrication process that the given virtual metrology model is configured, and
• wherein the instructions cause the computing system to determine the selected subset by:
• performing a value analysis process on the process parameters applied for the given step of the semiconductor fabrication process, the process parameters applied for the subsequent step of the semiconductor fabrication process, and the wafer value for the given step of the semiconductor fabrication process that the given virtual metrology model is configured to predict in order to determine impact contributions to the wafer value predicted by the subsequent virtual metrology model for the subsequent step of the semiconductor fabrication process;
• and
• determining the selected subset based on the impact contributions determined through the value analysis process.