Sonochemical Surface Modification of Electronic Materials ... · Sonochemistry Centre at Coventry...
Transcript of Sonochemical Surface Modification of Electronic Materials ... · Sonochemistry Centre at Coventry...
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Sonochemical Surface Modification of Electronic Materials
Dr Andy Cobley
The Sonochemistry Centreat Coventry University
New Developments in PCB and Interconnect Manufacturing NAMTEC, Rotherham UK
4th August 2009
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Agenda
1.Surface Modification in Electronic ManufacturingProblems associated with traditional methods
2.What is SonochemistryAcoustic cavitation
Advantages for surface modification
3.Sonochemical Surface Modification
Preliminary work
Optimisation
Commercial applications
4. Lean, Green and Clean Processing?
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Traditional ‘Wet Chemical’ Surface ModificationSubstrates Chemistry HazardsPCBs, MIDs other polymers
Solvent Swell VOC, flammable
PCBs, MIDs other polymers
Alkaline Permanganate
Highly caustic, strong oxidant
ABS Chromic acid Carcinogenic, highly acidic
Ceramics, glass
Hydrofluoric acid
Causes burns, targets bone
•Hazardous Chemistry
•VOC’s, carcinogens, corrosive
•Environmental and health and safety legislation
•High Waste Treatment costs
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Traditional ‘Wet’ Surface ModificationSummary
Traditional surface modification processes characterised by…..
•Long process times
•High temperature baths
•High water usage
•Hazardous chemistry
CAN SONOCHEMISTRY HELP ?
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
SonochemistryThe effect of sound on the chemistry of a solution
I I I I I I I I 0 10 10 10 10 10 10 10
2 3 4 5 6 7
Human hearing 16Hz - 18kHz
Conventional power ultrasound 20kHz - 100kHz
Extended range for sonochemistry 20kHz - 2MHz
Diagnostic ultrasound 5MHz - 10MHz
THE FREQUENCY RANGES OF SOUND
I I I I I I I I 0 10 10 10 10 10 10 10
2 3 4 5 6 7
Human hearing 16Hz - 18kHz
Conventional power ultrasound 20kHz - 100kHz
Extended range for sonochemistry 20kHz - 2MHz
Diagnostic ultrasound 5MHz - 10MHz
THE FREQUENCY RANGES OF SOUND
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface ModificationAcoustic Cavitation
5000 oC2000 ats
bubbleforms
bubble grows in successive cycles
reachesunstable size
undergoesviolent collapse
compression compression
rarefactionrarefaction rarefaction rarefaction rarefaction
compression compression
5000 oC2000 ats5000 oC2000 ats
bubbleforms
bubble grows in successive cycles
reachesunstable size
undergoesviolent collapse
compression compression
rarefactionrarefaction rarefaction rarefaction rarefaction
compression compressioncompression compression
rarefactionrarefaction rarefaction rarefaction rarefaction
compression compression
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
boundary layersolid surface
Acoustic Cavitation in a liquid NEAR A SURFACE
UNSYMMETRIC COLLAPSEInrush of liquid from one sideof the collapsing bubbleproduces powerful jet of liquid targeted at surface
•Thinning of diffusion layer•Surface Cleaning•Surface activation•Improved mass and heat transfer
Video courtesy of University of Twente, Netherlands.and Shimadzu Europa GmbH, Duisburg, Germany
Microjetting/Microstreaming
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Microjetting/Microstreaming
DEMO
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface Modification
• Microjetting– Mechanical/physical attack of surface– Scrubbing/cleaning action– Destruction of boundary layers– Movement of reactants to, and
products/debris away from, the surface• Extreme temperatures and pressures
– Chemical/oxidative attack of the surface due to oxidative species
– Breaking of bonds on surface of material– Chemical reactions on surface
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface Modification Original Research Concept
Use ultrasound to make existing surface modification processes more ‘sustainable’
•Reduce chemical concentrations
•Reduce process times
•Reduce temperatures
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface Modification
Isola 370HR – Tg 180 ºC
Materials Tested
Cycolac S705 – ABS/PC
Noryl HM4025 – Polyphenylene ester / polystyreneCourtesy of Moulded Circuits
Ceramic Material
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Experimental Set-upPreliminary work
20 kHz Ultrasonic probe
Water in
Water out
Water Jacket
Solution
Sample holder
Sample
Thermostat
•All experiments performed at 40 ºC
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
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Solution Code
Without UltrasonicsWith ultrasonics
Sonochemical Surface ModificationEffect of Ultrasound on Existing Surface Modification Processes
Weight loss results for Ceramic Material
DI Water
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface Modification of Ceramic
30 minutes HF Etch
1 minute HF Etch 1 minute Sonication in Water, 20 kHz
30 minutes Sonication in Water, 20 kHz
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Ductile-like area vs. sonication time
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Sonication time (minutes)
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Sonochemical Surface Modification of Ceramic
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface Modification in Water20 kHz Horn, 29.3 W / cm2, 60 minutes in DI Water, 40 ºC
Isola 370HR as received x500 After Sonication x500
Noryl HM4025 as received x500 After Sonication x500
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface ModificationConclusions from Preliminary work
Initial work indicated that sonochemical surface modification could be achieved in water – a more sustainable liquid medium
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface Modification in Water Optimization of Ultrasonic Frequency
Noryl HM4025, 40 ºC, 30 minutes
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface Modification in WaterOptimization of Ultrasonic Intensity at 20 kHz
Effect of Ultrasonic Intensity on Weight loss for Noryl HM402520 kHz, DI Water, 40 ºC, 15 minutes
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface Modification in WaterOptimization of Probe to Sample Distance
Effect of Probe to Sample Distance on Weight Loss for Isola 370HR20 kHz, 4.8 Wcm-2, DI Water, 40 ºC
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5 mm probe to sample distance25 mm probe to sample distance
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface Modification in Water Other Factors Affecting Process
Standard Process
Bubbled Argon1% 3323
Low temperature
‘Standard’ Process20 KHz Ultrasonic probeDI water @ 40 ºCIntensity – 4.8 W/cm2Time – 15 minutes
Isola 370HR
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface Modification in WaterEffect of Optimization on Weight Loss for Noryl HM4025
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229.3 W/cm2, 40 ºC, 60 minutes
4.8 W/cm2, 6 ºC, 15 minutes
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface Modification of ABSModified process
As received After Sonication at 40 kHz
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Potential Commercial Applications
Metallization of Polymeric Microspheres
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface Modification of Polystyrene Polymeric Microspheres
As received After Sonication at 20 kHz
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Electroless Copper Plated Polystyrene Microspheres
UntreatedSonicated at 20 kHz
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface Modification of Electronic MaterialsConclusions
• Significant sonochemical surface modification can be achieved on a variety of materials used in electronic manufacture using water as the liquid medium
• The project has identified a number of factors influencing sonochemical surface modification
– Frequency– Ultrasonic intensity– Probe to sample spacing– Liquid temperature– Added surfactant etc
• Under optimised conditions process times reduced from 60 minutes to 15 minutes and weight loss has increased by a factor of 4 on Noryl material
• Other factors have also been identified which can further enhance the sonochemical surface modification and patent protection is being sought
• The project has produced a technology platform from which potential commercial applications are emerging
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface ModificationA route to Lean, Green and Clean
Manufacturing ?
LEANOne stage process
GREENLower temperatures, reduced energy costs, less rinsing, lower
waste treatment costs.
CLEANNon-hazardous chemistry
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
The Sonochemistry Centre at Coventry UniversityFaculty of Health and Life Sciences
Coventry UniversityCoventry, CV1 5FB, UK
www.coventry.ac.uk/sonochemistry
CONTACT DETAILS
[email protected] - +44 (0) 24 76 888 624
Mobile – 07706 955 901Fax +44 (0) 24 76 888173
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface ModificationProject funded by
Industrial and Academic Partners
MOULDED CIRCUITS LTD
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Sonochemistry Centre at Coventry University “The Home of Sound Science”
Thank you
Any Questions ?