Russell J. Holmes

Identification and quantitative analysis of contaminants found in photolithography purge gases

The measurement of organic and inorganic contaminants in photolithography purge gas is validated to below a 1 part-per-trillion lower detection limit using a Cold Trap concentrated method. To investigate the contaminant loading history into a purifier during its lifetime, a Purifier Information Retrieval Service (PIRS) is developed with measurement sensitivity below 0.01 microgram. This method is validated by accurately loading and unloading known challenges of contaminants into a GateKeeper purifier. The result indicates that if a purifier is operating at 100% duty cycle and 1 slm for 1 year, an annual quantitative measurement average of the impurites in the process gas of less than 5 part-per-quadrillion can be achieved.

Surface Passivation of New Channel Materials Utilizing Hydrogen Peroxide and Hydrazine Gas

In Situ gas phase passivation methods can enable new channel materials. Toward this end pure anhydrous HOOH and H2NNH2 membrane gas delivery methods were developed. Implementation led to Si-OH passivation of InGaAs(001) at 350C and Si-N-H passivation of SiGe(110) at 285C. XPS and initial electrical characterization has been carried out. Feasibility for In Situ dry surface preparation and passivation was demonstrated.

Effects of high moisture on the purification of clean compressed air

A method was developed to measure hydrocarbons to 1 part-per-trillion (ppt) concentration levels with a gas chromatograph and flame ionization detector (GC/FID). This method was used to measure purifier siloxane removal efficiencies from air under dry and humid conditions. Several media types were examined: activated carbon (AC), bead-shaped activated carbon (BAC) and a proprietary inorganic material (PIM). Under dry conditions, all three materials removed the siloxane challenge to below 1ppt. The AC material had a removal efficiency of 286 ppt under humid conditions. The BAC and PIM removed the siloxane challenge to below 1 ppt under humid conditions. After media saturation was reached under humid conditions, the materials were regenerated and siloxane removal efficiencies were re-examined. Only the PIM material was regenerable to below 1ppt efficiency levels.

Contaminant dry-down rates in photolithography purge gases

Adsorption and desorption rates of a 6-component hydrocarbon mixture and SO2 have been studied on the surfaces of Ultra High Purity (UHP) components under the presence of parts-per-billion (ppb) contaminant levels. The dry-down rates are monitored to sub parts-per-trillion (ppt) levels. In the hydrocarbon test, stainless steel components are confirmed to be more effective than Teflon during dry-down. Dry-down rates for hydrocarbons on stainless steel (SS) surfaces depend on the molecular weight of the contaminant; heavier molecules take longer to dry-down. The dry-down study for SO2 revealed that it will desorb from Teflon surfaces quicker than it will desorb from stainless steel. The result of UHP valves tested for outgassing indicates that Extreme Clean Dry Air (XCDA) was able to remove hydrocarbons to lower levels and cleanup faster than with a N2 purge.