EEMD based pitch evaluation method for accurate grating measurement by AFM

- The EEMD based pitch evaluation method with better applicability is proposed.
- EEMD based method could improve pitch precision and grating line position precision.
- AFM nonlinearity was stable, and smaller in x axis and forward scanning.
- A detailed pitch uncertainty evaluation model for commercial AFMs is demonstrated.
- The grating pitch uncertainty was reduced about 10% by EEMD.