SEMI M35 - Guide for Developing Specifications for Silicon Wafer Surface Features Detected by Automated Inspection
Inspection of silicon wafer surfaces is a standard outgoing test on all commercially sold silicon wafers.
Older specifications referred to visual inspection of wafer surfaces, but with advanced technologies, the sizes of many important surface features are too small to be seen visually and so other types of surface inspection become necessary.
This Guide provides a specification framework for reporting measurements of silicon wafer surface features through the use of scanning (or automated) surface inspection systems (SSIS).
This Guide addresses specifications related to localized light scatterers (LLSs) as well as extended light scatterers (XLSs). Examples of LLSs are particles and pits. Examples of XLSs are scratches and regions of high roughness (surface haze). Illustrative examples of many of the features discussed in this Guide may be found in SEMI MF154.
Surface scanners, which have discriminated between XLSs and LLSs for several years, are now discriminating (and selectively reporting) between different types of LLSs (e.g., pits and particles).
Specific numbers limiting feature levels and/or densities are to be agreed upon between suppliers and customers. This Guide provides a framework for that communication that result in specifications flexible enough to accommodate variations in measurement due to different SSIS models.
Referenced SEMI Standards
SEMI M1 — Specification for Polished Single Crystal Silicon Wafers
SEMI M53 — Practice for Calibrating Scanning Surface Inspection Systems using Depositions of Monodisperse Polystyrene Latex Sphere on Unpatterned Semiconductor Wafer Surfaces
SEMI M59 — Terminology for Silicon Technology
SEMI MF154 — Guide for Identification of Structures and Contaminants Seen on Specular Silicon Surfaces