SEMI F112 - Test Method for Determination of Moisture Dry-Down Characteristics of Surface-Mounted and Conventional Gas Delivery Systems by Cavity Ring Down Spectroscopy (CRDS)
This Standard was technically approved by the Gases Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on June 4, 2013. Available at www.semiviews.org and www.semi.org in June 2013.
This Document describes the procedure for determination of the moisture dry-down characteristics (quantity of removable moisture) of surface mount (integrated gas delivery systems) and conventional gas delivery systems using cavity ring down spectroscopy (CRDS) analyzers.
The results of this test can be used for qualitative ranking of gas delivery system based on the design. It can also be used by a sufficiently sophisticated user as input for numerical simulation of a gas distribution system behavior.
This Test Method applies to all types of surface mount and conventional gas delivery systems used in semiconductor processing.
Test Medium — The test medium shall be nitrogen. Other ‘inert’ gases will have different purging characteristics and may dry a system more quickly or slowly. Reactive gases shall not be used as they may react chemically with moisture. Considerations relating to corrosion resistance are outside the scope of the present document, although the test procedure may prove useful in corrosion studies. The results will provide a ranking with respect to moisture contribution arising as a result of differences in design, which may be applied with due caution to systems intended for use in other gas applications.
Operating Situations — Moisture contribution from a gas delivery system may be the result of contamination arising in its manufacture, or from subsequent exposure to ambient air or nondry gas. Thus, it is necessary to consider two main situations:
The ‘initial dry-down’ situation, which is determined by the moisture content of the components in the system (as received) with the effects of manufacturing process and design, surface quality, pretreatment and packaging convoluted together.
The ‘response to upset’ situation, which is determined by the amount of moisture taken up by the system and subsequently released in any exposure after receipt.
Referenced SEMI Standards
SEMI C15 — Test Method for ppm and ppb Humidity Standards