Control of Molecular Contaminants in Porous Low-k Dielectric Films and in UHP Gas Delivery Systems

Persistent Link:
http://hdl.handle.net/10150/195243
Title:
Control of Molecular Contaminants in Porous Low-k Dielectric Films and in UHP Gas Delivery Systems
Author:
Yao, Junpin
Issue Date:
2008
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
As compared to silicon oxide, porous low-k dielectric materials are more susceptible to molecular contaminants. As the device feature size decreases, control of molecular contaminants in porous low-k dielectric films and in UHP gas delivery systems becomes increasingly more challenging. Moisture was selected as the principal model contaminant in this research because the moisture impurity retained in the dielectric films not only increases the effective dielectric constant (k) value of the films but also degrades the reliability of the device. Dry-down of moisture contaminated UHP systems takes days to weeks, which significantly decreases the process throughput. In this research, the fundamental interaction mechanisms of moisture with spin-on porous methylsilsesquioxane (p-MSQ) and Black Diamond IIx (BDIIx) dielectric films were investigated through isothermal challenge-purge processes at different exposure environments. Mass spectrometers (APIMS and EIMS), and cavity ring-down spectroscopy were used to detect moisture concentration in the gas phase. The moisture concentration in the thin films was directly analyzed by Fourier transform infrared spectroscopy (FTIR). Transmission Electron Microscope (TEM) micrographs were used to evaluate how patterning processes change the films. Moisture solubility, impact of temperature and gas flow rate on moisture removal, and dynamics of moisture uptake and removal in the films were determined by experimental study.Two process models were developed. The first one is capable of predicting the dynamic aspects of moisture adsorption and desorption in the films, and the second one is used to predict dry-down of moisture-contaminated gas delivery systems. The parameters in the models, such as moisture solubility and diffusivity in the films and rate constants of adsorption and desorption on the surface of the electro-polished stainless steel tube, were extracted through fitting these models to the experimental data. The models can be used to optimize key operating conditions such as purge temperature, purge gas purity, and purge gas flow rate. The models are also valuable tools for developing efficient contamination control strategies and process recipes for contamination removal in porous low-k dielectric films and for minimizing the gas usage in gas delivery systems.
Type:
text; Electronic Dissertation
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Chemical Engineering; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Shadman, Farhang
Committee Chair:
Shadman, Farhang

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleControl of Molecular Contaminants in Porous Low-k Dielectric Films and in UHP Gas Delivery Systemsen_US
dc.creatorYao, Junpinen_US
dc.contributor.authorYao, Junpinen_US
dc.date.issued2008en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractAs compared to silicon oxide, porous low-k dielectric materials are more susceptible to molecular contaminants. As the device feature size decreases, control of molecular contaminants in porous low-k dielectric films and in UHP gas delivery systems becomes increasingly more challenging. Moisture was selected as the principal model contaminant in this research because the moisture impurity retained in the dielectric films not only increases the effective dielectric constant (k) value of the films but also degrades the reliability of the device. Dry-down of moisture contaminated UHP systems takes days to weeks, which significantly decreases the process throughput. In this research, the fundamental interaction mechanisms of moisture with spin-on porous methylsilsesquioxane (p-MSQ) and Black Diamond IIx (BDIIx) dielectric films were investigated through isothermal challenge-purge processes at different exposure environments. Mass spectrometers (APIMS and EIMS), and cavity ring-down spectroscopy were used to detect moisture concentration in the gas phase. The moisture concentration in the thin films was directly analyzed by Fourier transform infrared spectroscopy (FTIR). Transmission Electron Microscope (TEM) micrographs were used to evaluate how patterning processes change the films. Moisture solubility, impact of temperature and gas flow rate on moisture removal, and dynamics of moisture uptake and removal in the films were determined by experimental study.Two process models were developed. The first one is capable of predicting the dynamic aspects of moisture adsorption and desorption in the films, and the second one is used to predict dry-down of moisture-contaminated gas delivery systems. The parameters in the models, such as moisture solubility and diffusivity in the films and rate constants of adsorption and desorption on the surface of the electro-polished stainless steel tube, were extracted through fitting these models to the experimental data. The models can be used to optimize key operating conditions such as purge temperature, purge gas purity, and purge gas flow rate. The models are also valuable tools for developing efficient contamination control strategies and process recipes for contamination removal in porous low-k dielectric films and for minimizing the gas usage in gas delivery systems.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineChemical Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorShadman, Farhangen_US
dc.contributor.chairShadman, Farhangen_US
dc.contributor.committeememberOgden, Kimberly L.en_US
dc.contributor.committeememberHiskey, Brenten_US
dc.identifier.proquest2842en_US
dc.identifier.oclc659749913en_US
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