Unbiased roughness measurements from low signal-to-noise ratio scanning electron microscope images

Chris A. Mack; Joren Severi; Mohamed Zidan; Danilo De Simone; Gian F. Lorusso

doi:10.1117/1.JMM.22.2.021006

14 December 2022 Unbiased roughness measurements from low signal-to-noise ratio scanning electron microscope images

Chris A. Mack, Joren Severi, Mohamed Zidan, Danilo De Simone, Gian F. Lorusso

Journal of Micro/Nanopatterning, Materials, and Metrology, Vol. 22, Issue 2, 021006 (December 2022). https://doi.org/10.1117/1.JMM.22.2.021006

Abstract

Background

Measuring and subtracting scanning electron microscope (SEM) noise from a biased measurement of roughness leads to an unbiased roughness measurement. This unbiasing procedure becomes harder as the noise in the image increases. For low image signal-to-noise ratio (SNR) (below about 2), unbiased roughness measurement becomes less reliable.

Aim

It is important to understand the mechanism for the sensitivity of unbiased roughness accuracy to linescan SNR to look for ways to improve unbiased roughness measurement for very noisy images.

Approach

Using a combination of mathematical analysis, simulations, and experimental data, the role of pixel size and pitch in the SNR sensitivity are explored.

Results

All evidence points to the correlation of edge detection noise to true edge position as the cause of the errors in unbiased roughness measurement for very noisy images. For small pitch patterns, changes in feature edge position caused by feature roughness will cause changes to the linescan slope, which in turn changes the sensitivity of edge detection to SEM image noise.

Conclusions

Smaller pixel sizes and larger feature sizes are less sensitive to the SNR effects described here. For any algorithm used to measure unbiased roughness, the impact of linescan SNR must be carefully assessed.

Citation Download Citation

Chris A. Mack, Joren Severi, Mohamed Zidan, Danilo De Simone, and Gian F. Lorusso "Unbiased roughness measurements from low signal-to-noise ratio scanning electron microscope images," Journal of Micro/Nanopatterning, Materials, and Metrology 22(2), 021006 (14 December 2022). https://doi.org/10.1117/1.JMM.22.2.021006

Received: 19 September 2022; Accepted: 30 November 2022; Published: 14 December 2022

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available