Each new generation of integrated circuits and other nano-structured devices is produced at ever decreasing length scales. The extension of conventional liquid-phase processes for the manufacturing of these devices is uncertain. This work investigates the ability of liquids to wet nanoscale features. A model for wetting time is derived that may be used to identify those geometries for which wetting is critical. Conditions under which wetting time is significant may result in low yield and poor uniformity, and may require alternate-phase processing. Furthermore, the dependence of wetting time on the properties of the fluid are quantified so that fluids may be designed to have optimal properties and thus optimal performance for wetting. The resulting model can be used as a tool to predict future processing requirements, and when necessary, to design novel processes implementing alternative phase fluids such as gas-expanded liquids (GXLs). This study also quantitatively predicts specific effects associated with modified transport properties for dissolution and transport in nanoscale features. The use of GXLs is a particularly promising alternative to conventional liquid-phase processes. GXLs have superior mass transport properties relative to liquids, but can maintain the solvent strength necessary for IC process steps such as post-etch residue removal and photoresist stripping. In addition, the environmental benefits associated with CO2-based processes can be substantial. Conceptual demonstration of the use of carbon dioxide (CO2)-expanded liquids for photoresist and residue removal has been performed. GXLs containing up to 75% CO2 are equally as effective as the pure solvents for removal of PHOST-based films. These experiments indicate that GXLs have potential applications in photoresist stripping and post-etch residue removal, in which cost savings due to reduced solvent use can be substantial. The removal of films with GXLs has been evaluated primarily with x-ray photoelectron spectroscopy (XPS). Additionally, an in situ optical technique has been developed for film and GXL diagnostics. This technique has been used to evaluate the response of PHOST-based thin films to GXLs and to monitor density changes of liquids upon gas expansion.

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Typescript, etc. / Digitized by Kansas State University Libraries

Typescript, etc. / Digitized by Kansas State University Libraries

Digitized by Kansas State University Libraries

Call number: LD2668 .T4 1978 B32 / Master of Science

No description available.

No description available.

No description available.

Limited information exists regarding the efficacy of consumer-available antimicrobials for the use on produce surfaces. There is a strong focus on eliminating pathogens from produce at a commercial level, but consumers can achieve pathogen reduction in a domestic setting. The objectives were to determine the ability of consumer-available antimicrobials to disinfect waxed green bell peppers, determine the efficacy of knife cleaning methods, and assess the transfer of contamination. Peppers were inoculated via immersion in a cocktail of rifampicin-resistant Salmonella serovars and Escherichia coli O157:H7 to a final concentration of 5.6 ± 0.5 log CFU/cm2. In study 1, samples of 3 10-cm2 pieces of inoculated pepper were excised from smooth tissue and immersed in 3% (v/v) hydrogen peroxide (H2O2), 2.5% (v/v) acetic acid, 70% (v/v) ethyl alcohol (EtOH), or sterile distilled water (SDW) for various lengths of time. Following treatment, samples were immersed for 30 s in a neutralizer solution. For study 2, inoculated peppers were chopped into 1-cm2 pieces. Knives were treated with one cleaning method: no treatment (control), towel wipe (TW), running hot water for 5 s (5SW), running hot water for 10 s (10SW) or 1% (v/v) detergent solution followed by hot running water for 10 s (ST). After treatments, knives were used to chop cucumbers. Surviving Salmonella and E. coli O157:H7 for both studies were selectively enumerated on lactose-sulfite-phenol red-rifampicin agar following aerobic incubation of plates for 24 h at 35 °C. Hydrogen peroxide exposure for 5 min resulted in reductions of 1.3 ± 0.3 log CFU/cm2 for both pathogens. Following 1 min exposure to EtOH, pathogens were reduced by 1.3 ± 0.1 3 log CFU/cm2; exposure for >1 min did not result in additional reduction. Acetic acid exposure after 5 min resulted in a Salmonella reduction of 1.0 ± 0.7 log CFU/cm2, but for E. coli O157:H7, exposure resulted in no significant reduction (p<0.05) of pathogens compared to SDW at the various points. For study 2, 5SW, 10SW, and ST were equally effective for knife decontamination. No significant difference (p<0.05) was found between log CFU/cm2 on knife blade and log CFU/cm2 transferred to surface of cucumber; therefore, viable organisms remaining on the knife blade were transferred onto the surface of the cucumber. Findings suggest EtOH and H2O2 may be effective consumer-deployable antimicrobials for surface decontamination of smooth produce, and contaminated produce can contaminate other produce. Further research of antimicrobial exposure on produce sensorial characteristics is also advised in order to determine how various antimicrobial exposure times will affect the quality and sensorial characteristics of the produce commodity.