Airborne Organic Contamination Behavior on Silicon Wafer Surface

Habuka, Hitoshi; Ishiwari, Syuichi; Kato, Haruo; Okuyama, Kikuo

doi:10.1149/1.1536181

Cited by 29 publications

(40 citation statements)

References 17 publications

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“…[14][15][16][17] This model consists of first-order rates of adsorption and desorption as expressed in the following equation:…”

Section: Deposition Kinetics Of Dep and Dbp On Sio 2 Wafersmentioning

confidence: 99%

“…8 In a number of recent studies, the deposition kinetics of several phthalate compounds on silicon wafers have been reported for long exposure periods up to several days. [13][14][15][16] However, in actual semiconductor fabrication processes, the wafer exposure time is most frequently limited to only a few hours. Nonetheless, it is possible that, even at a short exposure time, the wafer surface density of oAMCs with relatively lower molecular weight (M W ) could exceed the threshold contamination levels to result in device deterioration.…”

Section: Introductionmentioning

confidence: 99%

“…[17][18][19] Besides, the adsorption and desorption rate constants of oAMCs have usually been evaluated based on the actual data from cleanroom ambiences contaminated with several organic compounds. [14][15][16][17] This approach may lead to biased results because the composition as well as the concentration of the oAMCs in cleanrooms may vary from plant to plant. In contrast, limited information on the deposition behavior of single phthalate compounds under a controlled environment is available in the literature.…”

Section: Introductionmentioning

confidence: 99%

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Short Time Deposition Kinetics of Diethyl Phthalate and Dibutyl Phthalate on a Silicon Wafer Surface

Kang

Den

Bai

2006

Ind. Eng. Chem. Res.

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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.

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“…[14][15][16][17] This model consists of first-order rates of adsorption and desorption as expressed in the following equation:…”

Section: Deposition Kinetics Of Dep and Dbp On Sio 2 Wafersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Short Time Deposition Kinetics of Diethyl Phthalate and Dibutyl Phthalate on a Silicon Wafer Surface

Kang

Den

Bai

2006

Ind. Eng. Chem. Res.

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“…The contamination is due to volatile organic compounds in laboratory air and in wafer storage containers, as well as to a surface hydration layer. 7,8 Past experience indicated that the contamination level would be on the order of 0.3 nm and would likely be the largest source of error in the ellipsometric thickness determinations unless physically eliminated or measured by another technique and subtracted from the total ellipsometric thickness of oxide plus contamination. Because of the time lapse between wafer fabrication at NC State University and measurement at NIST and SEMATECH, it was necessary to deal directly with the contamination.…”

Section: Ellipsometry Measurement and Analysismentioning

confidence: 99%

A Comparison of Thickness Values for Very Thin SiO[sub 2] Films by Using Ellipsometric, Capacitance-Voltage, and HRTEM Measurements

Ehrstein

Richter

Chandler‐Horowitz

et al. 2006

J. Electrochem. Soc.

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A comparative study of very thin SiO 2 film thickness values obtained from the three dominant measurement techniques used in the integrated circuit industry, ellipsometry, capacitance-voltage ͑C-V͒ measurements, and transmission electron microscopy ͑TEM͒ has been completed. This work is directed at evaluating the metrology capabilities that might support the development of thickness reference materials for very thin dielectric films. We used a variety of models to analyze ellipsometry measurements and used three different quantum-mechanical-based algorithms to account for substrate quantized states and depletion effects in the polysilicon electrode to analyze the C-V results. TEM measurements were conducted by both phase contrast high resolution ͑HRTEM͒ and atomic number ͑Z͒ contrast high-angle annular dark-field scanning transmission electron microscopy ͑HAADF-STEM͒. We found a range of thickness values with each of the methods, with an overlap of values among the three techniques. HRTEM and STEM values showed less consistency between wafers than did ellipsometry or C-V, and seemed to be influenced more by local variations such as interface nonuniformities. We present sources of variation and estimates of the primary components of uncertainty for the measurements employed and discuss the implications of these results for obtaining consistent and unified film thickness metrology and for possible reference standards.The relentless shrinking of metal-oxide semiconductor ͑MOS͒ transistor dimensions, including component films and layers, has resulted in dramatic challenges to the process metrology for the thickness of gate dielectric films, the thinnest of the transistor components. As stated in the International Technology Roadmap for Semiconductors ͑ITRS͒, for high-performance logic the equivalent oxide thickness will be less than 1 nm in 2007, the 3-three process tolerance values for gate dielectric films are already below 0.1 nm, and the requirements for precision of any measurement to monitor the film fabrication process is ten times smaller yet ͑i.e., less than 0.01 nm͒. 1 Ellipsometry continues to be the measurement of choice for monitoring film thickness because it is rapid, nondestructive, and highly precise. Ellipsometry is essentially a first-principles measurement because the analysis to obtain film thickness is based on Maxwell's equations. However, the numerical values obtained for thickness depend on an assumed film structure model, as well as on the optical index values assumed for the silicon substrate, the gate dielectric film, and any other layers involved. The result is that ellipsometry-based thickness measurements, which can be very precise for a fixed set of model assumptions, are not absolutely accurate.High-resolution transmission electron microscopy ͑HRTEM͒ and scanning transmission electron microscopy ͑STEM͒ cross-sectional analyses provide a measure of the thickness of interface layers below the gate dielectric, and through lattice imaging of the silicon substrate, they provide a direct li...

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“…Particularly, the influence of gas velocity should be clarified, because not only the QCM sensor, but also the wafers are usually exposed to air at the position having various air velocities depending on the arrangement of the wafers and the equipment (15,16,25,26). Therefore, the adsorption and desorption of water and diethyl phthalate (DEP), widely known contaminant (3,5) on silicon surface, are studied in detail using the quartz crystal microbalance method in ambient nitrogen having wide ranges of humidity, average gas velocity and DEP concentration, in addition to our previous studies (22,23).…”

Section: Introductionmentioning

confidence: 99%

Influence of Gas Velocity and Humidity on Diethyl Phthalate Adsorption and Desorption on Silicon Surface

et al. 2006

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The real-time adsorption and desorption of water and diethyl phthalate on silicon surface were studied using a quartz crystal microbalance in ambient nitrogen, having various values of humidity, gas velocity and diethyl phthalate concentration. In a steady state, the adsorbed amount of water and diethyl phthalate is considered to depend only on each concentration in the ambient nitrogen. However, in a non-steady state, the gas velocity at the quartz crystal microbalance enhances both the adsorption rate and the desorption rate. Therefore, the gas velocity at the measurement point is concluded to be one of the key parameters that influence the organic contamination measurement.

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Airborne Organic Contamination Behavior on Silicon Wafer Surface

Cited by 29 publications

References 17 publications

Short Time Deposition Kinetics of Diethyl Phthalate and Dibutyl Phthalate on a Silicon Wafer Surface

Short Time Deposition Kinetics of Diethyl Phthalate and Dibutyl Phthalate on a Silicon Wafer Surface

A Comparison of Thickness Values for Very Thin SiO[sub 2] Films by Using Ellipsometric, Capacitance-Voltage, and HRTEM Measurements

Influence of Gas Velocity and Humidity on Diethyl Phthalate Adsorption and Desorption on Silicon Surface

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