SEMI E141 - Guide for Specification of Ellipsometer Equipment for Use in Integrated Metrology
This Standard was technically approved by the Metrics Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on December 21, 2010. Available at www.semiviews.org and www.semi.org in February 2011; originally published July 2005.
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.
The application of integrated metrology is anticipated to become a key factor for advanced process control in future integrated circuit (IC) manufacturing. Important parameters, which are typically measured for the characterization and qualification of device manufacturing steps, are the thickness and the optical properties of fabricated layers and the critical dimensions (CD) of submicron structures. For the measurement principle of ellipsometry, which is commonly applied in both applications, different equipment and, hence, procedures and notations for data acquisition and modeling exist. If, therefore, ellipsometry is to be applied for integrated metrology equipment, the physical and the software integration into the equipment should be standardized to avoid efforts for specific installations depending on the equipment and fabrication environment.
The description of the mechanical integration of an ellipsometer into an equipment module (e.g., a front end module or an equipment chamber) comprises the:
- specification of the ellipsometer equipment and the spatial arrangement of the ellipsometer modules and components,
- specification of the relative position of the ellipsometer equipment to the equipment module, and
- specification of the mechanical interfaces to the equipment module.
A prerequisite for a standardized software integration of an ellipsometer is the standardized notation of the layer counting method, the measurement parameters, the measurement data, and the measurement results. This document describes the position of the metrology equipment with respect to the sample. The position of the measurement position (i.e., the position of the measurement spot) refers to the description of the wafer surface coordinate system as described in SEMI M20.
The purpose of this Standard is to provide a guide for a unique specification of the most commonly applied ellipsometer equipment, the comprised modules and components, and their spatial arrangement. In this Standard, the notation for parameters required in data acquisition and modeling is specified, and a unique notation for remote access on measurement parameters, data, and results is provided. Derived from these definitions, the required parameters to identify the calibration status of an ellipsometer are specified. Additionally, recommendations for preferred physical units are given.
This Standard is intended for use in integrated metrology, but may also be applicable for stand-alone metrology.
This Standard covers reflection ellipsometric measurements in integrated metrology.
This Standard covers the typical applications of ellipsometry, which are the determination of layer thickness and optical properties.
Referenced SEMI Standards
SEMI E30.5 — Specification for Metrology Specific Equipment Model (MSEM)
SEMI E89 — Guide for Measurement System Analysis (MSA)
SEMI E127 — Specification for Integrated Measurement Module Communications: Concepts, Behavior, and Services (IMMC)
SEMI M20 — Practice for Establishing a Wafer Coordinate System
SEMI MF576 — Test Method for Measurement of Insulator Thickness and Refractive Index on Silicon Substrates by Ellipsometry