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Researchers Submit Patent Application, "Ultraviolet Light Activated Oxidation Process for the Reduction of Organic Carbon in Semiconductor Process...

June 18, 2014



Researchers Submit Patent Application, "Ultraviolet Light Activated Oxidation Process for the Reduction of Organic Carbon in Semiconductor Process Water", for Approval

By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Sitkiewitz, Steve D. (Sebastopol, CA); Carmignani, Gary M. (Occidental, CA); Frederick, Lee W. (Bodega Bay, CA), filed on January 31, 2014, was made available online on June 5, 2014.

No assignee for this patent application has been made.

News editors obtained the following quote from the background information supplied by the inventors: "Reducing TOC in water using ultraviolet light activated aqueous persulfate is known. It is an established method of decomposing organic compounds in water and is discussed in, for instance, U.S. Pat. No. 4,277,438, to Ejzak, which teaches a batch process of preparing water samples for the measurement of TOC by: (1) persulfate addition, (2) irradiation with an extreme dose of UV (which also heats the sample) to activate the persulfate to oxidize any TOC to carbon dioxide and water. U.S. Pat. No. 5,443,991, by Godec et al, teaches a similar method.

"U.S. Pat. No. 5,571,419, to Obata et al, discloses a method of producing Ultra Pure Water (UPW) having a low concentration of organic matter. The purification method requires the following process for the water to be treated: (1) pH adjustment to less than 4.5, (2) addition of an oxidizing agent (such as a persulfate salt), (3) heating of the water to preferably a minimum of 110.degree. C. and more preferably to 120.degree. to 170.degree. C., and (4) cooling the water to the temperature required for use.

"The prior art also includes references showing an advanced oxidation process to destroy organic compounds in wastewater, including U.S. Pat. No. 5,762,808, to Peyton, and U.S. Pat. No. 6,096,283 to Cooper et al.

"However, despite improvements in this technology, there remains a need for an improved method of producing a reliable, continuous source of low TOC UPW for the semiconductor industry and other industries that require ultrapure water with controlled total organic carbon.

"The present disclosure describes UV activation of persulfate salt to produce high oxidation potential radicals at ambient temperature, in non-pH adjusted water to purify UPW prior to discharge from the Point of Distribution (POD), prior to the Point of Connection (POC) (typically labeled as the Point of Use or POU), and to purify spent UPW for reuse on a continuous basis."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "This disclosure is a process used for the decomposition of carbon-containing compounds in water. This process reduces total organic carbon (TOC) in water through the addition of a persulfate salt upstream of an ultraviolet light source. The ultraviolet light is absorbed by the persulfate--converting the persulfate into sulfate radicals. The sulfate radicals oxidize TOC, converting the contributing compounds into CO.sub.2 and mineral salts.

"This disclosure describes the use of the UV/persulfate oxidation process for the purification of water used in semiconductor manufacturing and the production of UPW in general.

"The process uses a standard photochemical reactor either a plug flow (PFR) or a stirred tank (CSTR) or a combination of both. The most cost-effective design is expected to be a CSTR with immersed UV lamps. Multiple reactors can be used in series to improve reagent utilization.

"A method of reducing TOC in semiconductor process water is disclosed.

"Other features of the disclosure, regarding organization and method of operation, together with further objects and advantages thereof will be better understood from the following description considered in connection with the accompanying drawings, in which embodiments of the disclosure are illustrated by way of example. It is to be expressly understood, however, that the drawings are for illustration and description only and are not intended as a definition of the limits of the disclosure. The various features of the disclosure are pointed out with particularity in the claims annexed to and forming part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

"The disclosure will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

"FIG. 1A is a schematic view of an advanced oxidation system in accordance with one or more embodiments;

"FIG. 1B is a block schematic diagram of a semiconductor industry UPW system showing possible locations in which the advanced oxidation system could be employed in accordance with one or more embodiments;

"FIG. 2 is a graph showing the absorption spectrum for aqueous persulfate;

"FIG. 3 is a graph showing the effect of urea concentration on decomposition performance for plug flow reactor, with persulfate at 0.5 ppm and a 0.9 minute residence time; and

"FIG. 4 is a graph showing the results of a simulated pilot test of the system to treat spent rinse water in accordance with one or more embodiments."

For additional information on this patent application, see: Sitkiewitz, Steve D.; Carmignani, Gary M.; Frederick, Lee W. Ultraviolet Light Activated Oxidation Process for the Reduction of Organic Carbon in Semiconductor Process Water. Filed January 31, 2014 and posted June 5, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5332&p=107&f=G&l=50&d=PG01&S1=20140529.PD.&OS=PD/20140529&RS=PD/20140529

Keywords for this news article include: Patents, Electronics, Semiconductor.

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Source: Electronics Newsweekly


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