Swabs, Wipers Critical for Semiconductor/Disk Drive Industries
Antistatic swabs, presaturated wipers lead trends in product category.
By Sheila Galatowitsch
Wipers do for surfaces what HEPA filters do for air, says Dr. Howard Siegerman, senior marketing manager for The Texwipe Company (Upper Saddle River, NJ). Wiping is the only cleaning technique that provides sufficient energy to remove submicron particles held by strong electrostatic energy,
Siegerman says. Wipers are critical to the maintenance of any cleanroom, especially in ultraclean semiconductor fabs, where the use of presaturated wipers is becoming a necessary convenience.
The disk drive industry could not survive without swabs,–the wiping implement used to clean tiny, hard-to-reach places,–and modern magneto-resistive (MR) heads have pushed the development of antistatic swabs. “Charges as low as 50 volts can destroy MR heads,” says Texwipe`s marketing director, Rob Linke. “Without an ESD-safe swab, you run the risk of blowing every single head coming down the line.”
Texwipe is among the U.S. swab and wiper manufacturers and distributors participating in a market that will double by the year 2000. In 1995, the worldwide market for swabs and wipers was $254 million, according to research conducted by The McIlvaine Co. (Northbrook, IL). By 2000, global sales will have reached $500 million. The semiconductor industry is the world`s largest user, consuming nearly half of the product category, with the disk drive, pharmaceutical and other electronics industries lining up consecutively as the next largest user groups.
The emerging flat panel display industry is the fastest growing user group, according to The McIlvaine report. Sales to this industry will balloon from $4.8 million in 1995 to $22 million in 2000. The automotive industry will double its expenditures from $15 million in 1995 to $30 million in 2000, and the medical device and food industries will also increase their use of cleanroom swabs and wipers by the turn of the century.
Daily requirement
Workers in some industries use as many as 1,000 wipers each year for daily cleaning of parts, components, instruments, equipment, work surfaces and the cleanroom itself; general spill cleanup; preparation of surfaces; and for “cleanbuild” construction applications.
Users evaluate wipers based on the wiper material and its solvent compatibility, absorption rate, cleanliness and cost. As in many other segments of the cleanroom industry, the semiconductor industry demands the lowest levels of particulate, extractable, ionic and ESD contamination in the wiper products it uses, setting the pace for other industries. Available in both natural and synthetic fibers, wipers made of 100 percent polyester knits tend to be cleaner than wipers made of other materials, such as cotton, nylon and rayon. Polyester knits are also durable and provide chemical and solvent resistancy. Some claim it is not as absorbent as other materials, although wiper manufacturers are addressing that concern in new product lines. “Sealed-edge, polyester wipers are the state of the art and will be for the next five to ten years,” says Jack McBride, president of wiper manufacturer Contec Inc. (Spartanburg, SC).
Most users will end up making trade-offs between cost, cleanliness and absorption, says Mike Mattos, sales manager of swab and wiper distributor A.J. Reynolds (Torrance, CA). “You can have clean, low-cost or absorptive–but not all three,” he says.
The need for cleanliness is even more critical in a swab than a wiper, because swabs actually touch a product to do intricate cleaning. Swabs are used primarily by the disk drive industry to clean the space between the head and the drive, by the pharmaceutical industry for surface sampling analysis and validation, and by other industries that hand-assemble products. They are also used for general cleaning in hard-to-reach places. For the head, cotton, foam and polyester are most often selected. Wood, plastic, nylon and polypropylene are the materials of choice for the handles, as well as the new polymers engineered to dissipate static. Swabs are used either dry or with a solvent such as isopropyl alcohol. Users evaluate swabs based on head and handle materials, head attachment method, head construction size, stick flexibility, solvent resistancy, absorption, cleanliness and cost.
Available in a number of head, handle and size configurations, “swabs are almost totally application specific,” says Contec`s McBride. “Today, the market is skewed toward tiny, clean swabs,” says Texwipe`s Linke, who adds that his company has automated its manufacturing processes to produce its own line of ultra-small precision swabs.
Swabs
Swab manufacturer Coventry Clean Room Products (Kennesaw, GA) has recently introduced a line of non-contaminating conductive and static-dissipative MR technology swabs. Conductive and static-dis- sipative swabs are available either with sealed foam heads or sealed fabric heads. Conductive swab handles dissipate 99 percent of a positive or negative 5 KV charge in 0.01 seconds. Static-dissipative swab handles dissipate up to 90 percent of a positive or negative 5 KV charge in less than 1.0 second. The handles have a surface resistivity of 103 ohms/square for conductive swabs and 1010 ohms/square for static-dissipative swabs.
Swabs are manufactured in the company`s Class M1 cleanroom facilities and have been tested by disk drive companies in the U.S., as well as third-party testing companies in the U.S. and Singapore, according to Dr. Mo Tazi, director of research and development. The new swabs were developed in answer to customer requests for a swab that is ESD-safe, but also solvent-resistant, especially to acetone.
Coventry views the MR technology swabs as a first step towards a new type of swab altogether,” says Tazi, which will be developed for even more stringent needs. In designing the new product, the company investigated various ESD-safe polymers for the handle, “but we are now starting to look at materials used with the head. Some of these materials are quite unique,” he says. In addition to its six lines of swab products, Coventry also carries seven types of wipers.
Texwipe has recently introduced swabs to sample surfaces for pharmaceutical cleaning validation. The long-handled Alpha Swab and the Large Alpha Swab are made from a double layer of Class 1 cleanroom-laundered polyester, while the heads are thermally bonded onto polypropylene handles. They feature ultra-low background levels of carbon and low extractable levels to provide a neutral background for sampling. The Alpha Swab has a head size of 0.25 x 0.66 in. and a 5.8-in. long, flexible handle. The Large Alpha Swab has a head size of 0.50 x 1.01-in. and a 4-in. rigid handle. Texwipe manufactures its swabs and wipers, including the Alpha 10 Sealed-Edge Cleanroom Wiper line, in a Class 1 laundry and cleanroom facility.
Wilshire Technologies Inc. (Carlsbad, CA) offers dissipative swabs of Class 10 cleanliness. The 1700 Series UltraSolv Swabs provide continuous Class 10 dry or low-solvent cleaning and absorbency in a wide range of solvents including acetone. The 1900 Series UltraSolv Swabs are ESD-safe, dissipating 5 V-50,000 V in 2/10th second. Recently, Wilshire introduced its HT1914HD rigid spear-pointed swabs for ESD-safe cleaning in HDD head/stack assembly, electronic micropackaging cleaning and semiconductor probe cleaning. The company`s swabs and wipers are made from a proprietary polyurethane material that meets the specifications for Class 1 and Class 10 ESD-safe rooms.
Wipers
Swab and wiper manufacturer Berkshire Corp. (Great Barrington, MA) last year introduced a line of wipers specifically engineered for use during cleanroom construction. The ProjX 1000 is a polyester/cellulose non-woven wiper designed specifically for the early stages of construction, and the ProjX 2000, a knitted polyester wiper, laundered and packaged in a Class 10 cleanroom, is suitable for the later stages of construction. The ProjX 2000 is absorbent and low in particle generation, extractables and metallic ion content.
Another wiper manufacturer is Lym-Tech Scientific (Chicopee, MA), which also distributes a line of swabs. Its wiper line features a range of materials, including the Twill Jean wiper, a tightly woven cotton wiper that is highly absorbent yet low-linting. The company`s newest product is the Sorbont-HS wiper, developed from DuPont Corp.`s Criticlean HS, a contamination-control fabric. A cellulose-and-polyester blend, non-woven fabric, it provides a thick, bulky structure for high absorbency and low particulate and extractable contamination.
Lym-Tech has recently installed a new, automated packaging line in its Class 100 and Class 10 cleanrooms where wiper materials are converted. Immediately after the wiper undergoes the final cut, it is automatically packaged in a double polybag, eliminating the need for worker intervention.
Rippey Corp. (El Dorado Hills, CA) distributes sponges and wipers made of polyvinyl alcohol (PVA). PVA has a continuous pore structure similar to a natural sea sponge, which gives the products elasticity for durability and also helps them absorb and retain liquids without leaving a residue. The material does not shed lint or fibers or scratch surface areas. The wipers are available in three sizes: 9″ ¥ 9″ ¥ 1 mm, 9″ ¥ 9″ ¥ 2 mm, and 17″ ¥ 13″ ¥ 1.5 mm.
Presaturated wipers
Since wipers are used almost exclusively with solvents for cleaning applications, more users are requesting presaturated wipers with their solvent of choice. Contec has introduced presaturated wipers in a bulk pack which contains 30 to 50 wipers per package. Most wiper manufacturers now offer presaturated wipers with a variety of solvents. The most typical solvent-used is isopropyl alcohol and DI water, but disinfectants, specialty detergents, surfactants, water-based systems and organic solvents are also available.
The advantages of presaturated wipers are numerous. Before their introduction, solvents were stored on-site in drums. Users mixed liquids in-house, poured them into bottles for dispensing, then faced disposal of both the solvent and wiper. Presaturated wipers make it easier and safer to work with sometimes hazardous solvents, and at the same time, reduce the amount of solvent consumed in the manufacturing process. The product is especially important to pharmaceutical and medical device users, who must mix solvents according to FDA protocols. With presaturated wipers, users can now specify exact solvent recipes from their suppliers.
Contec carries presaturated versions of its entire wiper line, which includes ProSat, Quiltec, ProZorb and the Wall WipR Cleaning System. The company will also custom blend for specific applications in a separate Class 1,000 cleanroom facility dedicated to the custom product line. Filling is performed under a Class 10 hood, and equipment design allows fast change-over to different solvents.
Hal Sharpe Associates Inc. (Chico, CA) distributes Contec`s Satwipes presaturated wipers. The roll of 100 6- ¥ 9-in. saturated wipers is dispensed through a center-pull canisters. Users can specify wiper materials and solvents, as well as proprietary solvents. The Satwipes line can also be irradiated for sterile use.
Another wiper distributor is Servitex Cleanroom Services (Durham, NC), which offers the latest addition to the Texwipe CleanPaks line of presaturated wiping systems–the TX1057 CleanPak. Designed specifically for the wiping and cleaning of Class 10 cleanroom work surfaces, the TX1057 CleanPak consists of ultraclean, sealed-edge polyester wipers presaturated with semiconductor-grade isopropyl alcohol solution. The wipers are packaged in a resealable dispenser.
Berkshire has recently introduced a line of presaturated wipers called SatPax. The standard line is comprised of six products, each packaged in a resealable, cleanroom-compatible pouch. Standard wiping materials include nonwoven polyester/cellulose, knitted polyester and sealed-edge, knitted polyester. Solvents are semiconductor grade and include 2-Propanol, metered for consistency, and reverse osmosis/DI water. The company can also accommodate custom requests.
Liberty Industries (East Berlin, CT) manufactures a pre-entry wet wiper that measures 6 ¥ 9 in. The non-foam wiper is saturated with DI water and isopropyl alcohol and packaged in a pop-up dispenser. The wipers are suitable for general cleaning of tools, personnel surfaces and equipment.
Distributors
Connecticut Clean Room Corp. (Bristol, CT) converts DuPont Sontara material into wipers in its Class 100 cleanroom and also distributes products from major manufacturers. The Sontara wipers feature high absorbency and low linting. Connecticut Clean Room caters to small- and medium-sized companies, says John Goodwin, director of sales and marketing, by providing quick turnaround on special-cut requests, unusual quantities and proprietary solvents.
Another distributor, A.J. Reynolds Co., specializes in validation consulting on swabs and wipers. It is currently distributing the 31040-ESD Static Dissipative Swab with a 2.75-in. blue handle that dissipates 90 percent of a 1 KV charge in 0.01 seconds. The handle is acetone/solvent resistant and effective in all levels of humidity. The 0.12-in. knit polyester head is also resistant to most common solvents. Sales manager Mike Mattos says his users are looking for application-specific swabs and wipers that are also cost-effective.
Contamination Control Products (CCP) (Marlboro, NJ) is a distributor of Coventry`s line of swabs and wipers. CCP offers wipers in light and heavyweight polyesters with or without sealed edges, a composite polyester/cellulose blend, reticulated foam, nylon, meltblown polypropylene or nylon/polyester microfiber Chamois wipers. Sizes range from 4 ¥ 4 in. to 36 ¥ 36 in.
Perotech Sciences (Buffalo, NY) distributes swabs and wipers from Berkshire, Coventry, Chemtronics, Hardwood Products Co. (PurSwab), Lym-Tech and Kimberly Clarke in upstate New York, Ontario and Quebec. The company also supplies Texwipe products through its associate distributors.
Both manufacturers and distributors predict users will continue to request application-specific products. Coventry`s Tazi says more users will ask for nonstandard wiper sizes in a variety of fabric choices. To meet that need, Contec`s manufacturing line has the capability of cutting wipers in virtually any size. Meanwhile, new users are discovering cleanroom swabs and wipers for lint- and fiber-free cleaning. Lym-Tech Vice President Peter Hogan says he is seeing more sales to the automotive industry, which is using a polyester knit wiper for cleaning cars prior to painting. Currently, Contec has two patents pending on presaturated wipers specifically for the automotive industry. n
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The worldwide market for swabs and wipers will double in the next few years, from $245 million in 1995 to $500 million in 2000. The semiconductor industry is the world`s largest user, while the emerging flat panel display industry is the fastest growing user group, with sales expanding from $4.8 million in 1995 to $22 million in 2000.
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ProSat Custom knitted wipers from Contec are made of meltblown polypropylene fabric that can be saturated with a variety of standard or custom solvents.
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In addition to its line of wipers, Berkshire manufactures swabs in a variety of sizes and materials.
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This ESD static-dissipative swab, distributed by A.J. Reynolds Co., dissipates 90 percent of a 1 KV charge in 0.01 seconds and is acetone/solvent resistant.
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Liberty Industries manufactures a pre-entry wet wiper, a 6 x 9-in. general use wiper for tools, personnel surfaces and equipment..
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Texwipe`s new Large Alpha Swab is a polyester swab that can be used for cleaning broad surfaces and flat areas, also for pharmaceutical surface sampling and cleaning validation. It has a head size of 0.50 x 1.01 in. with a 4-in. rigid handle.
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The Texwipe Co.`s black inspection wiper is made specifically for inspecting previously wiped cleanroom surfaces to verify the cleaning process.
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Polyvinyl alcohol (PVA) is used in wipers and sponges distributed by Rippey Corp. The sponge-like PVA is soft, durable and absorbent.
Where to Find Swabs and Wipers…
Company Phone
Advanced Clean Room Devices (310) 483-8400
A. J. Reynolds Co. Inc. (310) 784-3800
Alameda Industries (619) 487-4400
Berkshire Corp. (413) 528-2602
Calapro Inc. (714) 282-0690
Clean ESD Products (510) 659-1803
Clean Room Accessories Inc. (614) 792-5344
Connecticut Clean Room Corp. (860) 589-0049
CCP-Contamination Control Products (908) 780-3211
Contec Inc. (864) 591-2210
Controlled Environment Equipment (207) 854-9126
Controlled Environment Products (816) 453-8900
Coventry Clean Room Products (770) 424-4888
Dryden Engineering (510) 440-1890
Dycem (401) 738-4420
Eastwater Scientific Products (800) 786-6027
Hal Sharpe Associates Inc. (916) 899-1555
Hardwood Products/PurSwab (207) 876-3311
J & G Cleanroom Laundry Inc. (864) 627-1624
Laminaire Corp. (908) 382-6300
Liberty Industries (860) 828-6361
Lym-Tech Scientific (800) 628-8606
Miller Products Co. Inc. (201) 662-2010
Milliken & Co. (706) 880-5255
Paxxis (415) 592-1999
Perotech Sciences Inc. (800) 515-0089
Rippey Corp. (916) 939-4332
Servitex Cleanroom Services (800) 522-2186
Stern & Stern Industries (212) 972-4040
Supply Doctor (800) 395-3356
Teijin Shoji (USA) Inc. (212) 840-7328
Terra Universal (800) 767-0114
The Texwipe Co. LLC (800) TEXWIPE
Thomas West Inc. (415) 592-0806
Ultrapure Technology (770) 932-0309
Veltek Associates Inc. (610) 524-7585
Warner Industrial Supply (800) 328-5482
Wilshire Technologies Inc. (800) 433-3340