Browsing by Author "Kang, YH"

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Direct quantitative analysis of phthalate esters as micro-contaminants in cleanroom air and wafer surfaces by auto-thermal desorption-gas chromatography-mass spectrometry
(2005-04-08)
Kang, YH
;
Den, W
;
Bai, HL
;
Ko, FH
;
環境工程研究所
This study established an analytical method for the trace analyses of two phthalate esters, including diethyl phthalate (DEP) and di-n-butyl phthalate (DBP), known as the major constituents of cleanroom micro-contamination detrimental to the reliability of semiconductor devices. Using thermal desorption coupled with a GC-MS system, standard tubes were prepared by delivering liquid standards pre-vaporized by a quasi-vaporizer into Tenax GR tubes for calibration. This method was capable of achieving detection limits of 0.05 mu g m(-3) for 0.1 m(3) air samples and 0.03 ng cm(-2) for 150-mm wafer surface density. Actual samples collected from a semiconductor cleanroom showed that the concentration of DBP in a polypropylene wafer box (0.45 mu g m(-3)) was nearly four times higher than that in the cleanroom environment (0.12 mu g m(-3)). The surface contamination of DBP was 0.67 ng cm(-2) for a wafer stored in the wafer box for 24 h. Furthermore, among the three types of heat-resistant O-ring materials tested, Kalrez((R)) was found to be particularly suitable for high-temperature processes in semiconductor cleanrooms due to their low emissions of organic vapors. This analytical procedure should serve as an effective monitoring method for the organic micro-contamination in cleanroom environments. (c) 2005 Elsevier B.V. All rights reserved.
Organic airborne molecular contamination in semiconductor fabrication clean rooms - A review
(2006)
Den, W
;
Bai, HL
;
Kang, YH
;
環境工程研究所
;
Institute of Environmental Engineering
Monitoring of airborne molecular contamination (AMC) has become a crucial element of cleanroom management as the production phase of semiconductor devices marches deep into sub-100-nm range. The current understandings of the AMC, particularly those with organic origins, are presented comprehensively in this article based on the research reports within the past ten years. Starting with a review of the chronological development of AMC problems and several approaches for the AMC classifications, this article also examines the merits of several available ambient sampling and surface analytical methods. The focal point of the article is to address the surface deposition potential of organic AMCs by experimentally correlating the surface speciation and abundance of the organic AMCs with their physical and chemical characteristics, together with the kinetic models delineating the rates of deposition for both single-and multiple-contaminant scenarios. In addition, the current progress of the AMC control strategies, especially the development of the chemical filtration technology, is also examined in the paper. (c) 2006 The Electrochemical Society.
Short time deposition kinetics of diethyl phthalate and dibutyl phthalate on a silicon wafer surface
(2006-02-15)
Kang, YH
;
Den, W
;
Bai, HL
;
環境工程研究所
;
Institute of Environmental Engineering
Short time adsorption and desorption behaviors of two alkyl phthalate esters, namely diethyl phthalate (DEP) and dibutyl phthalate (DBP), on silicon wafers exposed under various ambient concentrations were experimentally and theoretically investigated. The results showed that the surface density of DBP was significantly affected by both the length of exposure time and its ambient concentration, whereas that of DEP was only affected by its ambient concentration within the tested periods between 60 and 240 min. The determination of rate parameters for adsorption and desorption showed that the rate constants of DEP were always larger than those of DBP. Also, the sticking coefficient of DEP was larger during the initial adsorption stage due to its relatively lower molecular weight as compared to DBP. The value of the sticking coefficient for DEP, however, decreased much faster such that the value eventually became smaller than that for DBP. Therefore, for silicon wafers experiencing a short exposure time, organic compounds with lower molecular weights may be a more important source of airborne molecular contamination than those with higher molecular weights.