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Single-Digit Nanometer Electron-Beam Lithography with an Aberration-Corrected Scanning Transmission Electron Microscope
Published on: September 14, 2018
Metrology of lithographic features: balanced illumination eliminating diffractive bias
Applied Optics
|September 8, 2010
Summary
Optical microscopy achieves higher accuracy for shallow relief patterns by imaging phase features instead of intensity. This method minimizes diffractive bias, enabling precise metrology for micro-scale applications.
Area of Science:
- Optical Metrology
- Diffraction Physics
- Microscopy
Background:
- Traditional optical microscope metrology often relies on intensity imaging, which can introduce biases.
- Shallow relief patterns present challenges for accurate dimensional measurement using conventional techniques.
Purpose of the Study:
- To demonstrate a more accurate optical metrology approach for shallow relief patterns.
- To investigate the advantages of phase feature imaging over intensity imaging in microscopy.
Main Methods:
- Analyzing the principles of diffraction from phase discontinuities.
- Implementing specialized illumination or filtering to suppress intensity variations.
- Imaging phase features of shallow relief patterns using optical microscopy.
Main Results:
- Phase feature imaging significantly enhances accuracy and allows for smaller dimension measurements compared to intensity imaging.
- The proposed method eliminates diffractive bias inherent in traditional approaches.
- Achieved potential absolute accuracy within 0.1lambda for dimensions below 0.4lambda under ideal conditions.
Conclusions:
- Imaging phase features in optical microscopy offers superior accuracy for shallow relief pattern metrology.
- This technique is applicable to micro-fabrication fields like binary optics, integrated optics, and integrated circuits.
