SEMI M53 - Practice for Calibrating Scanning Surface Inspection Systems Using Certified Depositions of Monodispere Reference Spheres on Unpatterned Semiconductor Wafer Surfaces
This Practice describes calibration of scanning surface inspection system (SSIS) dark field detector channels so that the SSIS will accurately size polystyrene latex (PSL) spheres deposited on unpatterned polished, epitaxial, or filmed semiconductor wafer surfaces.
The purpose of this calibration is to ensure that different SSISs of a given manufacturer and model will assign the same light scattering equivalent (LSE) diameter to a specific localized light scatterer (LLS).
This Practice defines the use of LSE diameters, as defined in SEMI M59, as a means of reporting real surface defects whose identity, true size, and morphology are unknown.
This Practice provides a basis for quantifying SSIS performance as used in related standards concerned with parameters such as sensitivity, repeatability, and capture rate.
This Practice covers:
- Requirements for the surface and other characteristics of the semiconductor substrates on which the reference spheres are deposited to form reference wafers,
- Selection of appropriate certified depositions of reference spheres for SSIS calibration, including size distribution requirements to be met by the reference sphere depositions, but not the deposition method,
- Generation of calibration curves using model-predicted scatter data that have response curve oscillations and are thus not monotonic, and
- Generation of monotonic calibration curves using model-predicted scatter data.
Although it was developed primarily for use in calibration of SSISs to be used for detection of LLSs on polished silicon wafers with geometrical characteristics as specified in SEMI M1, this Practice can be applied to SSISs to be used for detection of LLSs on other unpatterned semiconductor surfaces, provided that suitable reference wafers are employed.
This Practice does not in any way attempt to define the manner in which LSE values are used to define the true size of LLSs other than PSL spheres (see ¶ 3.1).
This Practice supports requirements listed in SEMI M52.
Appendix 1 describes a method that may be used to determine the index of refraction of reference spheres that are not PSL.
Referenced SEMI Standards
SEMI M1 — Specification for Polished Single Crystal Silicon Wafers
SEMI M12 — Specification for Serial Alphanumeric Marking of the Front Surface of Wafers
SEMI M20 — Practice for Establishing a Wafer Coordinate System
SEMI M50 — Test Method for Determining Capture Rate and False Count Rate for Surface Scanning Inspection Systems by the Overlay Method
SEMI M52 — Guide for Specifying Scanning Surface Inspection Systems for Silicon Wafers for the 130 nm to 11 nm Technology Generations
SEMI M58 — Test Method for Evaluating DMA Based Particle Deposition Systems and Processes
SEMI M59 — Terminology for Silicon Technology