This Standard was technically approved by the global Micropatterning Committee. This edition was approved for publication by the global Audits & Reviews Subcommittee on May 13, 2011. Available at www.semiviews.org and www.semi.org in June 2011; originally published March 2004.
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.
This standard defines a unique language in the field of specification for, and qualification of, photomasks for use in optical lithography within the semiconductor industry.
At present only the International Technology Roadmap for Semiconductors (ITRS) serves as a universally accepted working document on how to specify photomasks, however the definitions used are subject to interpretation. Different tool makers, mask makers and mask users are hindered in the communication with each other, as they first need to know and understand each other’s terminology. The lack of a common terminology complicates comparison of tools. A uniformly used, and universally accepted terminology, with a minimum of ambiguity, is required.
The definitions listed are for mask qualification, incorporating 3 possible types of value for a given qualification parameter:
- <(true) qualification parameter>, which would be the result of an ideal measurement of the total population of features of interest.
- <measured qualification parameter>, the result of a given population of measurements. It is hereby mentioned that a measured value (for example the mean, the standard deviation, the range) is always subject to the sample size of the measured population and the measurement method. Therefore, both the sample size and the measurement method are mandatory information.
- <qualification parameter spec(ification)>, the maximum or minimum value that may not be exceeded for the selected population of measurements which must be defined as mandatory information.
The first two types of value for a given parameter, the true and measured qualification parameters, will be defined in the present document.
The third parameter type, the parameter specification, will not be discussed here, since it is subject to the agreement between the individual parties of the mask qualification process.
In order to assist users, the major differences in recommended default values between this standard and the ITRS mask table definitions are noted where applicable.
Referenced SEMI StandardsSEMI P10 — Specification of Data Structures for Photomask Orders
SEMI P19 — Specification for Metrology Pattern Cells for Integrated Circuit Manufacture
SEMI P21 — Guidelines for Precision and Accuracy Expression for Mask Writing Equipment
SEMI P22 — Guideline for Photomask Defect Classification and Size Definition
SEMI P24 — CD Metrology Procedures
SEMI P35 — Terminology for Microlithography Metrology