SEMI P47 - Test Method for Evaluation of Line-Edge Roughness and Linewidth Roughness
This Standard was technically approved by the Microlithography Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on February 6, 2013. Available at www.semiviews.org and www.semi.org in May 2013; originally published March 2007.
NOTICE: This Standard or Safety Guideline has an Inactive Status because the conditions to maintain Current Status have not been met. Inactive Standards or Safety Guidelines are available from SEMI and continue to be valid for use.
NOTICE: This Document was reapproved with minor editorial changes.
The purpose of this Document is to identify standard procedures for calculating the indices for the following two kinds of line roughness to characterize materials and processes for fine line pattern fabrication, especially in the integrated circuit manufacturing environment. The first index is related to the deviation of actual line-edge position from the ideal one (line of best fit) and is called ‘line-edge roughness’ (LER) The second index defines variation in the local linewidth and is called ‘linewidth roughness’ (LWR).
The scope of this Document is limited to description of the length of the edge or line (evaluation length) and the sampling interval in measurements, recording and presenting the LER or LWR of lines. The procedures described here can be generalized for other intended shapes (e.g., circles and arcs). Evaluation length determines the lowest observed spatial frequency, and the sampling interval determines the highest observed spatial frequency, while the sampling conditions and noise are properly considered.
The scope of this Document is limited to the apparent LER or LWR obtained by processing the two-dimensional image (signal intensity) of the observed line pattern, such as a result from critical dimension scanning electron microscopy (CD-SEM), atomic force microscopy (AFM), or other methods.
This Document describes measurand (see SEMI P35, ¶ 5.1.9) obtained from the two-dimensional image data.
Referenced SEMI Standards
SEMI P19 — Specification for Metrology Pattern Cells for Integrated Circuit Manufacture
SEMI P35 — Terminology for Microlithography Metrology
SEMI P36 — Guide of Magnification Reference for Critical Dimension Measurement Scanning Electron Microscopes (CD-SEMs)