Producing UltraPure Water

Dow Liquid Separations

Ultra pure water (UPW) is absolutelyessential to properly fabricate today’s inte-grated circuits. It is the primary cleaningsolvent used to rinse away all contaminantsand remnants of silicon etched away duringthe production process. The geometry oftoday’s integrated circuits is so minute andcomplex that even the smallest contaminantcan prevent a circuit from functioning properly. These contaminants decrease theproduction yield of usable circuits.

As the degree of integration becomesincreasingly more complex, the semicon-ductor industry requires higher levels ofwater purity. The amount of dissolved ionicsolids, organics, live bacillus, suspendedparticulates and silica must approach zero.In fact, the ultra pure water now requiredby the semiconductor industry typicallymust have a resistivity of 18.2 megohm.cm(0.055 microSiemens/cm) at 25°C, whileother ionic and non-ionic contaminantsmust approach non-detectable limits.

A single water treatment process cannotefficiently deliver water of such a high puritylevel. Experience shows that optimum watertreatment solutions take advantage of thespecific capabilities of reverse osmosis(RO), ion exchange and other technologies.Dow’s Liquid Separations business is uniquein the industry because it develops, manu-factures and offers a comprehensive rangeof RO membrane elements and ionexchange resins.

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The Need for Ultra Pure Water

We offer a complete line of FILMTEC®

semiconductor grade RO elements andDOWEX* MONOSPHERE* ultra purewater grade ion exchange resins to meetthe most stringent water purity standardsrequired to produce ultra pure water fortoday’s semiconductor devices.

For several years, we’ve been meeting theneeds of original equipment manufacturers(OEMs) and end use customers in the semi-conductor industry around the world. Thisexperience helps us to continually improveour own technology, manufacturing ionexchange resins and membrane productswith unsurpassed separation performanceand low contaminant levels that providelong-lasting, economical service.

*Trademark of The Dow Chemical Company

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Producing Ultra Pure WaterUltra pure water treatment systems varydepending on the source of the water tobe processed and ultimate purity influencedby the complexity of the semiconductordevice. Regardless of your system designand water source, Dow offers an extensiverange of products to meet your specificultra pure water needs (Figure 1).

Figure 1. Advanced UPW System Schematic

Dow has cooperated with OEMs and enduse customers in the development of UPWrecycle systems, as UPW recycling byproper classification of waste water sourcesand categorization of organic and inorganicimpurities has recently become moreimportant in water conservation strategies.

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DOWEX MONOSPHERE 550A UPW(OH) Type 1 strong base anion exchangeresin is used in the roughing, intermediateand polishing ion exchange loops either ina two bed system followed by a mixed bedor in a working mixed bed followingreverse osmosis.

Figure 2. DOWEX MONOSPHEREMR-3 UPW Conductivity and ∆TOCvs. Rinse Volumes

DOWEX MONOSPHERE ultra pure watergrade ion exchange resins offer significantimprovements in lower levels of TOC andrinse profiles to a resistivity of 18.2megohm.cm (0.055 microSiemens/cm).Figure 2 shows an example of rinse profilesfor DOWEX MONOSPHERE MR-3 UPWresin.

In addition, cation and anion exchangecomponents in mixed beds are designed toincrease removal capacity for silica, boronand other weak acid anions. DOWEXMONOSPHERE resins have uniform particlesize distribution which provides such benefitsas faster kinetics, shorter rinse times, betterregeneration efficiency and longer resin life(Figure 3). Our line of ultra pure watergrade resins includes...

Figure 3. DOWEX MONOSPHERE UPW Grade Ion Exchange Resins

DOWEX MONOSPHEREUltra Pure Water Grade Resins

Figure 4. DOWEX MONOSPHERE UPW Grade Ion ExchangeProducts for Ultra Pure Water Production

Strong Strong Weak Mixed Uniform Regen- NonAcid Base Acid Bed Particle erable Regen-

Cation Anion Cation Size erable

1. DOWEX MONOSPHERE 650C UPW (H) X X X

2. DOWEX MONOSPHERE C UPW (H) X X X

3. DOWEX MONOSPHERE 550A UPW (OH) X X X

4. DOWEX MONOSPHERE MR-3 UPW X X X

5. DOWEX MONOSPHERE MR-450 UPW X X X

6. DOWEX MAC-3 X X

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DOWEX MONOSPHERE 650C UPW(H) strong acid cation exchange resin is usedin the roughing ion exchange loop either ina two bed system followed by a mixed bedor in a working mixed bed following reverseosmosis. The color difference betweenDOWEX MONOSPHERE cation and anionresins makes it easy to verify that completeseparation has occurred when used inregenerable mixed beds.

DOWEX MONOSPHERE C UPW (H)strong acid cation exchange resin is used inthe roughing and intermediate loop in a twobed system. The cross linkage of this resinmakes it more efficient when frequent regen-eration is required, as is the case in theroughing stage and when ion exchangeprecedes reverse osmosis.

DOWEX MONOSPHERE MR-3 UPWresin is used as a working or polishingmixed bed to complement two bed ionexchange or reverse osmosis systems. Thecolor and particle size difference allow youto see the separation process, making it anideal resin to achieve optimum regenerationin a mixed bed.

DOWEX MONOSPHERE MR-450UPW grade resin is a non-separable homo-geneous mixed bed resin. It is used as apoint of use or non-regenerable mixed bedin the polishing loop to achieve low ppblevels of soluble silica, boron, sodium,potassium, sulfate, chloride, zinc, iron andaluminum. It is used for two to three yearsbefore replacement.

DOWEX MAC-3 resin is a macroporousweak acid cation exchange resin. The particle size is specially chosen for use inboth co-current and counter-current regener-ation systems. This resin efficiently removeshardness associated with alkalinity, and issuitable for ultra pure water systems wherehardness removal is necessary to operatethe reverse osmosis system at a higher pH.

Additional information about DOWEXMONOSPHERE UPW grade ion exchangeresins (including typical physical and chemical properties) is available in techni-cal data sheets.

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Dow offers a complete line of FILMTEC ROelements to suit specific ultra pure waterrequirements, based on water chemistryand OEM system design preferences.These elements have several distinguishingfeatures, including an interconnectordesign that eliminates feed leakage intothe permeate. FILMTEC elements are manu-factured by FilmTec Corporation usingautomated element fabrication, allowingoptimum leaf length and number of leaves,as well as precise placement of spacermaterials and glue lines. This provideshigher active surface area, consistent fluxand reduced fouling. FILMTEC elementsalso have structural integrity of the outershell through a stable, thoroughly curableepoxy resin and lower leachable rovingmaterials.

All of these FILMTEC elements take advan-tage of our high active membrane surfacearea technology to provide greater produc-tivity, higher salt rejection, lower foulingand potentially lower system operating costs.All FILMTEC brackish water elements achieve

a minimum stabilized overall rejection of99.5% and have earned a reputation ofmaintaining structural integrity and perfor-mance over chemical cleaning cycles.

FILMTEC BW30-365 element has anactive membrane area of 365 square feetand an average permeate flow of 9,500gpd (36 m3/d) under standard conditions.It offers high productivity because of itsincreased surface area, and it has a thickerbrine channel spacer that makes it idealfor high fouling situations where frequentcleaning is expected.

FILMTEC BW30-400 element is the mostcost-effective for new RO systems. The highsurface area of this product allows new ROsystems to meet productivity targets withfewer elements, and could possibly lead tolower system component and installationexpenses.

FILMTEC Brackish Water RO Elements

FILMTEC elements are built using advanced,precision production methods that reduceelement failure.

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FilmTec Corporation, a wholly ownedsubsidiary of The Dow ChemicalCompany, received ISO 9002 certifica-tion in September 1995, becoming thefirst membrane and element manufactur-ing facility to earn this certification. TheISO 9002 is an international model forquality assurance in production, installa-tion and servicing products.

About FilmTec Corporation...

FILMTEC BW30LE-440 element is usedto reduce energy consumption while main-taining reasonably high rejection. It oper-ates at about 150 psi compared to 225psi for conventional brackish water ROproducts, resulting in a substantial reduc-tion in operating cost.

BW30HR-440 element features our high-est rejecting brackish water membrane inan automated element construction and has440 square feet of active surface area. It isintended for use when the highest possiblesilica and TDS rejection is required, suchas when RO is followed by continuous orelectro deionization.

There are other elements available whichcan be heat sanitized at low pressure offline at a temperature up to 80°C. Heatsanitization can reduce or eliminate theneed for biocide treatment and subsequentrinsing operation, as well as the expenseof frequent chemical cleaning.

Other elements were recently developed toaddress the need for a consistently high pHfeed to achieve higher rejection of boron,silica, TOC and other weak acid anions.They can be used continually at a feed pHof 10.5 without decreasing the life span ofthe element. Please contact your Dow rep-resentative for more information aboutthese products.

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Semiconductor grade FILMTEC reverseosmosis elements provide significant bene-fits in ultra pure water production. FILMTECSGHR-390FF and SG30-415FF elementsfeature full-fit design†, eliminating the needfor tape and fiber glass outer wrapping,thus reducing sources of TOC contamina-tion. The full-fit design also eliminates thedead area behind the brine seal. There isfar less chance of bacterial growth andcontamination of the ultra pure water streambecause fluid flow takes place across theentire cross-sectional area.†When using full-fit elements it is recommended that cleaning inplace be practiced.

FILMTEC semiconductor grade RO elementsinclude...

FILMTEC SG30-415FF element has anon-fiberglass construction which eliminatesthe dead space behind the brine seal.This element can be heat sanitized, makingcleaning in place (CIP) an advantage inUPW systems with CIP flexibility. This elementhas excellent overall stabilized rejectionand very good rejection of isopropyl alco-hol. With a surface area of 415 squarefeet, this element is a good choice for theroughing and intermediate RO stages.

FILMTEC Semiconductor Grade RO Elements

Figure 5. FILMTEC Reverse Osmosis Products for Ultra Pure Water Production

Square Feet Stabilized Rejection1, % Full Low Heat Sanitizing/ Element MeOH EtOH IPA NaCl Si Fit Energy Capability

FILMTEC BW30-3652 365 29.5 44.2 89.5 99.5 - - - -

FILMTEC BW30-4002 400 29.5 44.2 89.5 99.5 - - - -

BW30HR-4403,5 440 - 53.2 95.3 99.7 99.9 - - -

FILMTEC BW30LE-4404 440 23.7 37.9 86 99.0 - - x -

SG30HS-390FF2,5 390 - - - 99.5 - x - x

FILMTEC SGHR-390FF2 390 23 50 95 99.4 99.6 x - -

FILMTEC SG-415FF2 415 17 40 94 99.2 99.4 x - -

SG30LE-4304,5 430 13 40.9 93.2 99.7 98.9 - x -

1Test Conditions of temperatures 25 degrees C, recovery 15%. 10 ppm of organic species plus:2Feed pressure 225 psi, 1500 ppm of NaCl, or 60 ppm of SiO2.3Feed pressure 325 psi, 1500 ppm of NaCl, or 60 ppm of SiO2.4Feed pressure 150 psi, 100 ppm of NaCl, or 1 ppm of SiO2.5Developmental product available for sale.

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FILMTEC SGHR-390FF element uses ahigh rejection membrane that offers excel-lent TOC and particle rejection andimproved resistivity compared to ultrafiltra-tion membranes, making it an ideal choicefor final polishing service. It has exhibiteda useful life of more than five years, result-ing in lower capital and operating costscompared to ultrafiltration membranes.

FILMTEC SG30LE-430 element wasrecently developed to meet the needs forhigher overall rejection, higher rejection ofsilica and lower molecular weight organiccompounds like isopropyl alcohol. This ele-ment also provides an accelerated TOCrinse down profile of less than 20 ppb inone hour. This low energy element is alsodesigned to operate continually in a pHrange of 10 to 11 to allow higher rejectionat lower applied pressure. A stabilizedrejection of 99.5% can be achieved within12 hours of start-up.

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Dow Products, Technology and Support

With our improved ROSA program, you can quicklyand easily predict the performance of FILMTECelements in specific systems.

Available service and support capabilities includeunbiased applications assistance, plant trials, operatortraining programs, and system optimization assistance.

Dow Liquid Separations is a global organi-zation serving the ultra pure water needsof the semiconductor manufacturingindustry in North America, Europe, Japanand southeast Asia. In addition to our lineof ultra pure water products, we providecomplete application assistance. We’ll helpyou select the exact combination of ROelements and ion exchange resins for yourwater quality needs. We can also help youdetermine the best time to clean or replaceyour elements and resins, and even provideyou with your own testing and monitoringprogram.

ROSAThe ROSA reverse osmosis system analysisprogram lets system designers and specifiersquickly and easily predict the performanceand operating economics of FILMTEC ele-ments in specific systems. To ensure thatdesigners and specifiers have the mostcomplete and accurate information possible,ROSA includes an interactive library oftechnical data. Also included is an Internetaccess to link users to the Dow Liquid

Separations home page on the WorldWide Web where they can obtain updatedinformation about FILMTEC elements.

Other Dow support services include planttrials, system optimization, operator trainingprograms, and the industry’s most up-to-date and comprehensive technical literature.Please refer to technical data sheets foradditional information, or contact the ultrapure water experts at Dow. For the locationnearest you, please see the back cover ofthis brochure.

Dow Europe

Dow Information CentreLiquid SeparationsSchurenbergweg 51105 AP Amsterdam ZuidoostP.O. Box 121211100 AC AmsterdamThe NetherlandsTel. +31 20 691 6268Fax +31 20 691 6418

Dow Pacific

Dow Chemical Australia Ltd.Liquid Separations26 Rodborough RoadFrench’s ForestNew South Wales 2086AustraliaTel. 61-2-9776-3226Fax 61-2-9776-3299

Dow Pacific

Dow Chemical Japan Ltd.Liquid SeparationsTennoz Central Tower2-24, Higashikanagawa 2-chome,Shinagawa-ku, Toyko 140JapanTel. (813) 5460 2100Fax (813) 5460 6246

Dow Latin America

Dow Quimica S.A.Liquid SeparationsRua Alexandre Dumas, 1671Sao Paulo - SP- BrazilCEP 04717-903Tel. 55-11-5188-9345Fax 55-11-5469-919

Dow North America

The Dow Chemical CompanyLiquid SeparationsP.O. Box 1206Customer Information CenterMidland, MI 48641-1206Tel. 1-800 -447-4369Fax 517-832-1465

Internet

http://www.dow.com/liquidseps

Dow Liquid Separations Offices

Form No. 177-01742-1297AMS*Trademark of The Dow Chemical Company CH 171-447-E-1297

NOTICE: No freedom from any patent owned by Seller or others is to be inferred.Becauseuse conditions and applicable laws may differ from one location to another and may changewith time, Customer is responsible for determining whether products and the informationin this document are appropriate for Customer’s use and for ensuring that Customer’s work-place and disposal practices are in compliance with applicable laws and other governmentalenactments. Seller assumes no obligation or liability for the information in this document.NO WARRANTIES ARE GIVEN; ALL IMPLIED WARRANTIES OF MERCHANTABILITYOR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.

Published December 1997.

FilmTec Corporation is a wholly owned subsidiary of The Dow Chemical Company.

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