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Dave Frost Senior Director of Business Development
Media Process Equipment
December 7, 2006
Precision Cleaning Process and Equipment Considerations for PMR media
2
Agenda
IntroductionDefect trendsEquipment evolutionCleaning overview
ContactNon-Contact Drying
PMR Considerations Conclusions
3
PMR cleaning “opportunity” comment from leading Industry Analyst
“The (PMR) head-disk interface is arguably the most intricate in the history of the HDD industry………..and cleanliness has both never been more important and less understood”
“Focus on PMR Transition” paperTrendFOCUS 8/1/06
4
Particle/Defect size as areal density increasesParticle/Defect size relation as areal density increases
The incredible shrinking defect
5
Maximum Critical Defect Size Roadmap
0
0.2
0.6
1.0
1.4
40 60 80 120 160 240 320 480 640 960 1.280
Capacity per 95mm disk, GB
Dia
met
er (µ
) 2005
2003
20112009
2007
LMR PMR
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Types of Defects to be removed via cleaning
Particles Head/Disk Interface issues that can cause a head crashMagnetic defectsCorrosionUsually can be caught at final test, before shipment
Film or StainsImpairs film adhesion Magnetic defectsCorrosion Difficult to detect and can grow over time, after shipment!
7
Cleaning Process and Equipment Evolution
Single Scrub
1984
150 DPH
Double Scrub + SRD
1988
300 DPH
1994
Fully integrated, multi-step processing
600 DPH
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Advanced Cleaning Systems for PMR Media and Substrates
1200 DPH
9
Advanced Cleaning Systems for PMR Media
2400 DPH
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Fundamental Cleaning Steps
Particle or defect underminingUse dilute soaps, detergents or performance chemistriesWeakening of molecular or physical bondWeaking of static bond
Particle or defect detachmentContact mechanism via torsion or normal shearNon-contact mechanisms from sonication forces
Particle or defect disposal Remove with filtration via recirculation
• High tank turnover and pump flow ratesQuick dump rinseAdvanced tank design and hybrid rinsing configurations
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Clean ability & Wet ability
The key to effective cleaning and drying is insuring the surface becomes and remains hydrophilic
Insures efficient particle undermining and engulfment in fluidInsures surface wetting is sufficient for drying performance
Source: IC Knowledge LLC
12
Advanced Cascade Scrubbing – 2400 DPH
1
43
2in
out
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Scrub Trends – more is better
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Ultrasonics
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Fundamentals of Ultrasonic Cleaning – Cavitation Forces
Ultrasonic sound waves moving through the cleaning fluid create cavities (cavitation) during the rarefied region of the waveCavities grow and then collapse or implode, causing high forces to be applied for detachment of defect
Source: IC Knowledge LLC
16
Ultrasonic Cleaning
Multiple Ultrasonic frequencies are required to insure acceptable removal efficiencies are met over the
broad range of particles sizes present on incoming substrates
Source: IC Knowledge LLC
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Sonic Frequency - simplified
Removing large particles easybut causes pitting defects
Small particles not removed
400 - 480 KHz 104 KHz
Removes both large particles and smaller particles effectively
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Megasonics – Final cleaning and rinsing prior to dry
Quick Dump Rinse Recirculated Rinse
Process flow
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Fundamentals of Megasonic Cleaning
Megasonic cleaning is excellent for removing smallest sizes particles, required prior to drying
Thinning of the boundary layer surrounding the particlesHigh velocity pressure waves
Source: IC Knowledge LLC
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Sonication Trends
Meg
ason
icFr
eque
ncy U
ltrasonic Frequency
Trend In Sonication
0
500
1000
1500
2000
2500
1985 1990 1995 2000 2005 2010 2015Year
0
50
100
150
200
250
300
350
400
450
500
MS Frequency US Frequency
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Megasonics is Trending Toward 100% Use
Ratio(MS/US)
0
20
40
60
80
100
120
1985 1990 1995 2000 2005 2010 2015
Years
Rat
io o
f MS/
US
Ratio(MS/US)
22
Drying Technology Roadmap
Drying Technology Comments
1. Spin Rinse Drying Particle generation - moving parts Throughput issuesNo longer used in media cleaning
2. Hot IPA Process Yield issues with NiP, Glass OKSafety, Environmental and COO issuesBeing eliminated in media cleaning
3. Hot DI Particle neutralityLower temperature processes possibleDual hand-off eliminates contact pointsContinuous development for PMR and beyond is occuring
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Tool Considerations
Key criteriaTechnology capability
• Contact, Scrubbing PRE• Non-contact, tank designs and sonic frequency and power density• Drying, glass and metal flexibility, particle size neutrality, temperature• Environmental control and particle generation control
Operational capability• COO, utilization, DT%, MTBF, MTTR, flexibility, extendibility
Throughput• Highest volume provides lowest cost• Lower volume for output granularity or line matching concept• Multiple size capability allows for best of both worlds
Floor space consumptionGlobal/Local service and technical supportPrice/Warranty/Availability of critical sparesManufacturing location should be near region of useR & D capability to provide continuous innovation and process improvement
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Substrate & Media Process Flow – LMR
Sputter
Clean & Dry
Laser Texture
Clean & Dry
Clean & Dry
Rough Polish
Clean
Final Polish
Clean & Dry
Final Grind
Substrate
Media
Optional
Texture
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Substrate & Media Process Flow – PMR
Sputter
Clean & Dry
Laser Texture
Clean & Dry
Rough Polish
Clean
Final Polish
Clean & Dry
Final Grind
Substrate
Media
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Information on PMR Cleaning Requirements
PMR media cleaning requirements are distinctly different than LMR;
PMR substrates are fundamentally different than LMR substrates due to the amount of incoming surface variability, so from a cleanability perspective PMR is more challenging than ever, because;
• PMR media does not require a texture step to aid in magnetic orientation, so the substrate surface enters the pre-sputter cleaner with an aged surface that is hydrophobic, consisting of:
• A thin oxide surface layer, based on time and storage environment metrics due to the fact substrates arrive from all over the world
• Polish induced surface asperities (scratches, nodules and ridges)• Adhered particles not removed by the final cleaning step after polish
due to existing lower capability • Loosely adhered, environmentally added particles
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Final Comments and Considerations on PMR Cleaning Requirements
PMR is prone to single point “Killer” defect at ~ 1µ and below
PMR requires several cleaning improvement considerations
Substantially improved cleaning requirements for incoming substrates due to texture process eliminationMore aggressive scrubbing, longer scrubbing times and/or increased surface contactMore complex soaps or aggressive chemistryImproved rinsing prior to drying, so particle free disks enter the dryerHigher frequency, multiple frequency megasonics and higher powerdensitiesEnhanced drying environment, to minimize particle adders, contact points and insuring complete drying
28
PMR HDD – Precision Cleaning Processes
Motor & Casting
Wafers
Head Fabrication
Substrate
Media Manufacturing
Burnish & Glide
Final Assembly
Head-Disk Assembly
PCB Assembly
Head Gimbal Assembly
HGA Test
Head-stack Assembly
Pack & Ship
Servo Track Writing
Pre-sputter Clean
HDA
PMR HDD
PMR Disk
PMR Head Certification
Production Test
Rough & Fine Polish CleanCMP Clean
Multiple Process Cleans
Precision cleaning is playing an increasingly important role in other areas:
29
End of Presentation
Q & A