Close FM Related 820.100 CAPAs with Root Cause Solutions

Foreign material (FM) is a leading source of CAPAs, rework and rejects at Class III medical device manufacturing facilities.

For manufacturing lines that employ polyurethanes, silicones, dip casting, sewing, hydrophilic coatings, epoxy operations, solvent bonding, cutting, deburring and complex assembly protocols, FM is often the leading cause of defects.

While there are many types of FM (which will be covered in future articles), dark-colored particulate matter, due to its visibility, ranks very high as a defect category and is a leading cause for non conformance reports and CAPA’s.  For Class III devices such as IOLs, cosmetic implants, neurological micro catheters, hydrophilic catheters, access devices and other cardiovascular devices, dark particle contamination alone generates defect rates in excess of 10%. In addition, related rework rates can easily exceed 30%.

Due to the severity of FM related issues, many Class III device manufacturers have implemented corrective actions that turn out to be ineffective because the source of the contamination was not properly identified.

Given the costs associated with open CAPAs, FM recurrence and nonconforming product, Class III device manufacturers need robust FM identification methods so that science-based root cause solutions can be developed.

SEM/EDX (Scanning electron microscopy with energy dispersive X-ray spectrometry) and FTIR (Fourier-transform infrared spectroscopy) are powerful analytical tools that are widely used to identify particulate contamination. Impeding the use of these tools in medical device manufacturing is the need to sample large and diverse surfaces. While many device manufacturers have used SEM/EDX and FTIR to identify contamination on components, backtracking to the source of the contamination has been far more difficult.

To leverage the power of SEM/EDX and FTIR to close CAPAs it is not enough to collect samples from the device. To be thorough, an investigation must tie the contamination on the device to the process and offending material. Because dark particulates have a wide variety of sources, it is a must to sample all related tooling and fixtures such as hand tools, automation, RF and ultrasonic welding dies, bonding tools, work surfaces and even floors, in order to perform a thorough investigation. Proper sampling involves collecting FM from both large surfaces as well as recessed areas of tools. The use of traditional SEM stubs requires a trained technician and is very expensive and time-consuming which has limited the appeal of this very powerful analytical method.

To assist Quality Engineers in developing root cause CAPA’s for dark particulate FM, Foamtec offers PolyCK wipers and swabs which are low cost and easy to use sample collection tools and combines this with SEM/EDX and FTIR analytical services to better solve vexing FM issues.

The following case study illustrates how contamination can be identified and eliminated. In this case rust colored FM was observed on devices, hand tools and gloves.

  1. Hand tools used to cut the device was sampled with the PolyCK swab

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                                 Area of the Tool that was Sampled

  2. Red particulate was visible on the PolyCK swab

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  3. The swab was pressed against a SEM stub

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  4. The SEM Stub was presented to the SEM/EDX instrument

    5

  5. The red particulate was identified as an organic and metallic particles

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  6. Using FTIR the organic red particulate was identified as uncured Loctite residue that had transferred to the cutting tool from in an upstream process

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Since Loctite is not used in the factory upstream suppliers are being audited and cleaning practices are being reviewed.

Foamtec’s low cost and easy to use surface sampling tools combined with a material science lab in an ISO 5 cleanroom have enabled Quality Engineers to develop root cause solutions to vexing FM contamination issues.

To learn how to identify and reduce sources of FM please click here for more information.

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Close FM Related 820.100 CAPAs with Root Cause Solutions

Better Housekeeping Means Improved EH&S Compliance in Compound Semiconductor Fabs.

In Compound Semiconductor fabs housekeeping is a vital part of the Environmental Health and Safety (EH&S) compliance. Toxic particulates comprised of GaN, GaAs, InP and other III-V elements are present on fab floors, walls and tool skins and the housekeeping practices must be designed to efficiently and thoroughly clean all these surfaces.

In order to control toxic particulate levels, compound semiconductor fabs employ stringent housekeeping SOP’s. A common practice is that fab floors are mopped multiple times per day while walls are cleaned daily or weekly.

In order to measure the effectiveness of current housekeeping practices, a GaAs fab employed Foamtec’s surface cleanliness audit procedure. This involves sampling the previously mopped or wiped surface with a PolyCHECK inspection wiper to measure post clean results. PolyCHECK is a black polyester fabric with high static attraction and is designed to collect samples from surfaces for further analysis by SEM/EDX or FTIR. The ability to collect samples from a larger surface area and then use a SEM stub to transfer the sample from the wiper to the SEM produces a much more rich set of data at far lower cost.

Figure 1 is the condition of a .25 square meter of surface as analyzed via SEM/EDX after the  fab floor have been mopped by the process of record(POR)

Slide5

Given the amount of toxic particulates in compound wafer fabs, an important component of a robust housekeeping SOP is the ability to clean underneath and behind process equipment.

In Figure 2 about .1 square meters underneath a process tool was sampled and highlights the difficulty housekeeping staff faces cleaning tight restricted spaces.

Slide6

Taking into account high spaces and large surface areas, vertical equipment surfaces and cleanroom walls present cleaning challenges to both equipment techs and housekeepers.

Cleanroom walls, depending on the type of mop employed often must be wiped. This is extremely time-consuming and prone to error given the inefficiency of hand wiping considering the amount of surface area involved.

Figure 3 is the surface cleanliness of .5 square meters of wall space at eye level after hand wiping with polycellulose non woven wipers.

Slide9

More problematic yet are tool skins which are often no man’s land for cleaning. Housekeeping staff is banned from touching equipment while the techs who are charged with equipment cleaning often do not have the time or ability to efficiently reach all the surfaces.

Figure 4 is the surface cleanliness after hand wiping with polycellulose of  25 square CM of a section of tool skin easily accessible to the tech.

Slide8

The data collected in figures 1-4 suggests that POR cleaning materials currently employed in housekeeping and equipment cleaning SOP are not sufficient to achieve EHS compliance goals.

To help Compound wafer fabs achieve safe working conditions, Foamtec has introduced PharmaSAT.

PharmaSAT employs two strips of Sahara foam laminated to a microfiber fabric and is presaturated with 100% ultrapure water of 10% IPA. The Sahara strips are designed to afford scratch free scrubbing of glass, plastic, ceramic and metal surfaces and to dislodge particulates that are stubbornly adhered and then entrapped and removed by the MiraWIPE microfiber fabric. The mop head fits on a super flexible mop frame and handle that offers great ergonomics and control enabling operators a tool to quickly and efficiently clean fab floors, walls, ceilings and even tool skins.

PharmaSAT’s unique MiraWIPE microfiber fabric enables all surfaces to dry within seconds of mopping to eliminate risks associated with drips and wet floors.

[Watch Video Below]

https://www.foamtecintlwcc.com/video/pharmasat-improves-wafer-fab-housekeeping

The lightweight swivel design of the handle and the scrubbing and pickup properties of the mop enable  operators to achieve much more thorough cleaning of tight spaces underneath and behind equipment.

Slide7

Unlike other mops, the PharmaSAT mop heads are more similar to presaturated wipers which allow techs to efficiently clean equipment skins before and after PM’s improving both safety and contamination control practices.

Slide2

For more information please visit us at our website:

www.foamtecintlwcc.com

Better Housekeeping Means Improved EH&S Compliance in Compound Semiconductor Fabs.

Cleaning Semiconductor Wafer Process Equipment with Ultrapure Water (UPW)

In modern 300mm wafer fabs, more and more equipment wet cleans are carried out with ultrapure water rather than IPA. The use of UPW is increasing as wafer fabs strive to reduce VOC’s and trace metal contamination levels. Moreover, metal etch and CMP equipment generate process by-products that are not soluble in IPA.

The use of water presents the fab with several challenges, including the need and difficulty in maintaining the purity and cleanliness of UPW which, by its nature, is magnet for contamination.

ipa-squirt-bottle

As the picture below highlights, squirt bottles used in PM’s are subject to many sources of contamination which have been shown to degrade the purity of water.

Squirt bottles are handled by operators whose gloves are quickly contaminated by the very nature of the PM process especially for tools that require the use of Scotch-Brite™ or ScrubPADS™ to remove hardened process by-product. Despite efforts by equipment and micro contamination engineers to install bottle, glove rotation and bottle washing protocols, many audits uncover bottles that should never be used in clean room let alone on an equipment PM.

To address the need to improve contamination control, Foamtec has introduced MiraSAT which is the first cleanroom wiper pre-saturated with Ultrapure Water. MiraSAT is specifically designed and constructed for fab wet cleans and is production-proven, in the most advanced sub-14 nm processes to reduce contamination excursions, test wafer consumption and tool down time.

mirasat-wiping-equipment

If you would like more information please view the following links:

MiraSAT Webpage
https://www.foamtecintlwcc.com/products/voc-free-wiping/mirasat-wipers

MiraSAT Datasheet
https://www.foamtecintlwcc.com/documents/datasheets/pdf/mirasat-wipers-datasheet-rev3.pdf

MiraSAT Application Note
https://www.foamtecintlwcc.com/documents/application-notes/pdf/mirasat-application-notes-rev02.pdf

 

Scotch-Brite Brand is a trademark of 3M.

Cleaning Semiconductor Wafer Process Equipment with Ultrapure Water (UPW)

Improving Contamination Control in Lubricious Coating Processes

In response to multiple adverse event reports related to the sloughing of lubricous coatings off  intravascular catheters, guidewires, balloon angioplasty catheters and delivery sheaths, device manufacturers have devoted significant resources to improve coating operations.

medical-device-manufacturer

While there are many failure modes in coating operations, foreign material (FM) contamination is often the most significant cause of inspection, rework and rejects. Given that FM directly impacts coating integrity, device manufacturers have upgraded clean rooms, garments, coating equipment and invested heavily in air ionizers in order to improve contamination control.

Despite these measures, FM remains a major failure mode and often leads to corrective and preventative action (CAPA’s) that cannot be closed with root cause solutions.

To reduce costly rework, defects and open CAPA’s, coating and quality engineers need a method to identify the sources of FM so that they can be targeted for reduction.

To aid device manufacturers, Foamtec has developed a sampling and identification service that is detailed in the following link:

https://img.foamtecintlwcc.com/documents/presentations/foamtec-fm-collection-and-identification-services.pdf

Pictured below are FM and material sources in ISO 5-8 cleanrooms by Foamtec’s FM collection and Identification service.

foamtec-sem-edx-polycellulose-hair-net-shoe-cover-fiber-residue-01Shown Above: Utilizing SEM/EDX instrumentation, FM is traced back to polycellulose non-woven wipers, bouffant caps and shoe covers recovered from a hydrophilic coating room.

foamtec-sem-edx-polycellulose-hair-net-shoe-cover-fiber-residue-02Shown Above: Polycellulose and polyester fibers were found as FM contamination on a hydrophilic coating linefoamtec-sem-edx-polycellulose-hair-net-shoe-cover-fiber-residue-03Shown Above: Using FTIR instrumentation, Foamtec was able to match the fibers found on the coating line with the catheter manufacturer’s current cleanroom wipers, bouffant caps and shoe covers.

For more information regarding FM Sampling and Identification, please contact us at www.foamtecintlwcc.com/contact

Improving Contamination Control in Lubricious Coating Processes

Mopping Wafer Fabs with UltraPure Water Reduces VOC’s Associated w/ IPA

Mopping of floors in large cleanrooms presents significant Environmental, Health and Safety (EHS) risks to wafer fabs, LCD fabs and microelectronics manufacturing sites. At the same time, cleanroom floors require frequent cleaning in order to meet ever tighter particle control budgets.
perforated-raised-cleanroom-floors
Typical Perforated Raised Cleanroom Floors
Due to the high surface tension of water and to guard against slip hazards, microelectronics facilities and especially wafer fabs consume copious quantities of IPA in mopping SOPs. While IPA aids cleaning and the quick drying of floors, the large volumes required present significant EHS challenges in the way of VOC emissions and fire hazards. In fact, it is typical that clean room mopping is the major source of VOC emissions in LCD and 300mm wafer fabs.
ipa-bottles
competitor-mop
Results from Facility’s Current Cleanroom Mop w/ IPA used to clean perforated raised floors
In many cleaning applications, microfiber fabrics are production proven to allow water to replace solvents and detergents. To improve cleaning and reduce mopping-generated VOC’s, Foamtec has introduced a microfiber mop that is pre-saturated with Ultra-Pure Water and designed to leave floors dry.
pharmasat-mop
Results from PharmaSAT Mop Presaturated w/ UPW used to clean the same surface

To learn more please visit the link below:

pharmasat-banner
PharmaSAT,™ presaturated with 100% UPW or 10% IPA, incorporates Foamtec’s industry leading MiraWIPE® Microfiber sealed edge wiper with Sahara foam strips to enable operators to dislodge, entrap and remove contamination including stubbornly adhered slurry, resist and implant residue. The proprietary weave and sealed edge provide unsurpassed resistance to abrasion and tearing to reduce in-use particle and fiber generation.
Mopping Wafer Fabs with UltraPure Water Reduces VOC’s Associated w/ IPA

Environmental Constraints for the Semiconductor Industry are only Increasing

Complying with EPA New Source Requirements(NSR) make Investing in new wafer fabs or expanding existing sites more costly and complicated.

 

As the following link makes clear plant expansions in non-attainment areas are even more complicated.

https://www3.epa.gov/ttn/catc/rblc/htm/welcome.html

To quote from the document:

The terms “RACT,” “BACT,” and “LAER” are acronyms for different program requirements under the NSR program.

RACT, or Reasonably Available Control Technology, is required on existing sources in areas that are not meeting national ambient air quality standards (i.e., non-attainment areas). BACT, or Best Available Control Technology, is required on major new or modified sources in clean areas (i.e., attainment areas).

LAER, or Lowest Achievable Emission Rate, is required on major new or modified sources in non-attainment areas.

While there are many sources of air pollutants that are emitted from wafer fabs a major pollution source is IPA soaked wipers. Cleanroom wipers either presaturated with IPA or wetted via squirt bottles are major source of VOC fugitive emissions. While some cleaning procedures can be accomplished with blends of water and IPA most require 100% IPA to produce clean dry surfaces. Depending on the size of the wafer fab, IPA wipers generate 5-30 tons of fugitive VOC emissions per year.

In order to help wafer fabs achieve a step change reduction in VOC fugitive emissions Foamtec has introduced the first cleanroom wiper pre-saturated with 100% Ultrapure water. MiraSAT®, due to its unique woven microfiber construction offers IPA like cleaning without all the VOC’s enabling tighter compliance with EPA and air quality control district air permits.

 

LEARN MORE ABOUT MIRASAT®

 

View MiraSAT® Webpage

Download MiraSAT® Datasheet

Download MiraSAT® Application Note

 

Environmental Constraints for the Semiconductor Industry are only Increasing

Prevent & Troubleshoot Defects in 200mm & 300mm Lithography Modules

Defects in 200mm & 300mm litho modules are a common, yet costly issue.

A major source of defects in lithography modules are fibers & particulates including resist particles that have been left in the track. Contamination that migrates to the scanner or stepper can result in serious defects including difficult to remedy hot spot and defocus issues.

wafer-handler defects-02 defects

Above: wafer handler End-Effector with hanging lint fiber will cause scratch signature on production wafer.

Reduce Defects at the Start

Foamtec International WCC has created a cleaning BKM/SOP that enables much more thorough cleaning so that Track equipment have higher first pass QUAL rates. As a result, backside wafer contamination is greatly reduced minimizing cross contamination on scanner wafer table.

The SOP is production proven to reduce the need for and harsh wafer table polishing (stoning) PM’s, where a round abrasive stone is used to recondition the surface of the wafer table to help prevent hot spots and defocus issues.  A frequent stoning procedure will reduce the lifetime of the expensive wafer table.

track-oven track-oven-02

Above: Track oven with Foamtec ergonomic cleaning tool

Foamtec’s Track cleaning SOP helps eliminate hot spots, reduce resist and the need to stone the scanner wafer table, resulting in improved uptime greatly reducing defects and cost.

Below, the defect reduction measured with a surface particle counter is evident.

particle-counter.jpg

 

For more information on Foamtec International’s BKM/SOP that will deliver a decrease in litho hot spots, fewer defocus issues, and longer time between stoning and cleaning of the table/chuck in the scanner email us at contact@foamtecintlwcc.com or visit our website at www.foamtecintlwcc.com

Prevent & Troubleshoot Defects in 200mm & 300mm Lithography Modules