Metrology is probably the most important part of semiconductor manufacturing aside from actually putting features on the wafer.

Statistical process control is at the heart of profitability, and measurement of what we've actually built is how it gets its data. If the accuracy and frequency of measurement goes up, the control loop tightens accordingly.

Parameterizing features and defects is a really interesting multidisciplinary process. Figuring out how to correlate defects at EDS time with something that occurred 80 process steps ago is where all the money lives in the business. Once you draw the correlation, you can place it under SPC and people will automatically get paged in the middle of the night the moment something starts to drift into an unhappy range.