- SEMI MF1811 - Guide for Estimating the Power Spectral Density Function and Related Finish Parameters from Surface Profile Data
This Standard was technically approved by the Silicon Wafer Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on August 31, 2016. Available at www.semiviews.org and www.semi.org in November 2016; originally published by ASTM International as ASTM F1811-97; previously published January 2016.
There is some confusion in the roughness-measurement community concerning the use of estimators and the calculation of power spectral densities (PSDs) from discrete data sets. Use of this Guide can eliminate these differences and result in the use of consistent units for the PSD and related parameters. It also provides a uniform reporting procedure for digital roughness data that can facilitate communication between different workers and different laboratories.
This Guide defines the methodology for calculating a set of commonly used statistical parameters and functions of surface roughness from a set of measured surface profile data. Its purposes are to provide fundamental procedures and notation for processing and presenting data, to alert the reader to related issues that may arise in user-specific applications, and to provide literature references where further details can be found.
This Guide is limited to the analysis of one-dimensional or profile data taken at uniform intervals along straight lines across the surface under test, although reference is made to the more general case of two-dimensional measurements made over a rectangular array of data points.
The data analysis procedures described in this Guide are generic and are not limited to specific surfaces, surface-generation techniques, degrees of roughness, or measuring techniques. Examples of measuring techniques that can be used to generate profile data for analysis are mechanical profiling instruments using a rigid contacting probe, optical profiling instruments that sample over a line or an array over an area of the surface, optical interferometry, and scanning-microscopy techniques such as atomic-force microscopy. The distinctions between different measuring techniques enter this Guide through various parameters and functions that are defined in §§ 4 and 5, such as their sampling intervals, bandwidths, and measurement transfer functions.
Referenced SEMI Standards
SEMI M59 — Terminology for Silicon Technology
SEMI ME1392 — Guide for Angle Resolved Optical Scatter Measurements on Specular or Diffuse Surfaces