In Focus: Resist Recess Depth Monitoring of Narrow Trenches

Publication in focus:
Franz Heider et al: AFM Surface Roughness and Depth Measurement of Trenches with High Aspect Ratio DOI: 10.1109/ASMC.2019.8791811

Discover how nanotools EBD4-200A probes are enabling metrology solutions for real-life semiconductor manufacturing. These heavy-duty carbon tips are effectively used for in-line process control for structures that cannot be measured with optical methos like scatterometry.

• Experimental setup:
  Samples: Resist recess trenches on product wafers. Trenches were filled with resist and then etched back.
  Tool: Park NX-Wafer operated in fully automated recipe mode, Park Systems
  AFM probe: EBD4-200A, nanotools
• Extracted feature parameters:
  Resist recess trench depth
• Key findings:
  Single AFM tool (200 nm narrow, 1035 nm deep trenches)
  0.6 nm < σ < 1.4 nm: 10-times dynamic repeatability of 5 dies
  Accuracy: dimensional verification by cross sections in SEM
  Measurement time: few seconds/site + 60 seconds for sample positioning
  2 AFM tools: Fab to fab matching (480 nm deep trenches)
  < 5 nm offset: 3 runs of 9-point recipe running the same wafer in 2 different fabs

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