c-tech innovation profitable growth through innovation
DESCRIPTION
C-Tech Innovation Profitable Growth through Innovation. Stuart Dalrymple Ultrasound as an enabling technology for sustainable electronic manufacturing. Ultrasound as an enabling technology for sustainable electronic manufacturing. Dr Andrew Cobley. Agenda. - PowerPoint PPT PresentationTRANSCRIPT
Click to edit Master title style
C-Tech Innovation Profitable Growth through Innovation
Stuart Dalrymple
Ultrasound as an enabling technology for sustainable electronic manufacturing
Click to edit Master title style
Ultrasound as an enabling technology for sustainable electronic manufacturing
Dr Andrew Cobley
Click to edit Master title style
Agenda1.Surface Modification in Electronic Manufacturing
Problems associated with traditional methods
2.What is Sonochemistry?
Acoustic cavitation
Advantages for surface modification
3.Sonochemical Surface Modification
Preliminary work
Optimisation
Conclusions
4. TSB project
5. Eco-Innovation project
Click to edit Master title style
Traditional ‘Wet Chemical’ Surface Modification
Substrates Chemistry Hazards
PCBs, 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
Click to edit Master title style
Traditional ‘Wet’ Surface ModificationSummary
Traditional surface modification processes characterised by…..
• Long process times
• High temperature baths
• High water usage
• Hazardous chemistry
CAN SONOCHEMISTRY HELP ?
Click to edit Master title style
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
Click to edit Master title style
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
Click to edit Master title style
boundary layer
solid 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
Click to edit Master title style
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
Click to edit Master title style
Sonochemical Surface Modification Original Research Concept
Use ultrasound to make existing surface modification processes more ‘sustainable’
• Reduce chemical concentrations
• Reduce process times
• Reduce temperatures
3 year Platform study funded by
Click to edit Master title style
Sonochemical Surface Modification
Isola 370HR – Tg 180 ºC
Materials Tested
Cycolac S705 – ABS/PC
Noryl HM4025 – Polyphenylene ester / polystyreneCourtesy of Moulded Circuits
Ceramic Material
Click to edit Master title style
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
Click to edit Master title style
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
Click to edit Master title style
Sonochemical Surface Modification in Water Optimization of Ultrasonic Frequency
0.0000
0.0500
0.1000
0.1500
0.2000
0.2500
0.3000
As Received
20 kHz Horn
40 kHz Bath
582 kHz Bath
863 kHz Bath
1142 kHz Bath
Wei
ght L
oss
(mg/
cm2)
Noryl HM4025, 40 ºC, 30 minutes
Click to edit Master title style
Sonochemical Surface Modification in WaterOptimization of Ultrasonic Intensity at 20 kHz
0.0000
0.0500
0.1000
0.1500
0.2000
0.2500
0.3000
0.3500
0.4000
0 2 4 6 8 10 12
Wei
ght
Los
s(m
g/cm
2 )
Ultrasonic Intensity (W/cm2)
Effect of Ultrasonic Intensity on Weight loss for Noryl HM402520 kHz, DI Water, 40 ºC, 15 minutes
Click to edit Master title style
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
-0.0500
0.0000
0.0500
0.1000
0.1500
0.2000
0.2500
0.3000
0 10 20 30 40 50 60
Wei
ght
Los
s (m
g/cm
2 )
Time (minutes)
5 mm probe to sample distance25 mm probe to sample distance
Click to edit Master title style
Sonochemical Surface Modification of ABSModified process
As received After Sonication at 40 kHz
Click to edit Master title style
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
• The project produced a technology platform from which potential commercial applications are emerging
Click to edit Master title style
HIGH EFFICIENCY PRINTED CIRCUIT BOARD PROCESSES
HEPROC Effect of Ultrasound on Permanganate Etch in Desmear Process
Nine Month Feasibility Project Funded by the Technology Strategy Board (TSB)
Click to edit Master title style
Desmear ProcessProcess Make - up Temp. (ºC) Time
M-Treat AQ(Solvent Swell)
20% v/v M-Treat K22 g/l NaOH
60 1 min 24 sec
Rinse 2 min
M-Permanganate P 0, 33, 65 g/l M-permanganate P0 or 32 g/l NaOH
5,25,40,60,85 2 min 48 sec
Rinse 3 X 1 min
Neutralizer 3% (v/v) H2SO4
3% (v/v) 37% H2O2
Ambient 48 sec
Rinse 2 min
DI Rinse 1 min
Permanganate – with/without ultrasound (vigorous stirring)Ultrasound – 20 kHz ultrasonic probe, Power 50 W, Probe to sample distance 5 mm
Click to edit Master title style
0.0000
0.0500
0.1000
0.1500
0.2000
0.2500
0.3000
0 10 20 30 40 50 60 70 80 90
Wei
ght L
oss
(mg/
cm2 )
Temperature (ºC)
33g/l KMnO4, 32g/l NaOH
Silent
Ultrasound
Effect of Ultrasound on PCB DesmearIsola 370HR Laminate
Baseline
Baseline value obtained using - 65g/l KMnO4, 32g/l NaOH @ 85 ºCUltrasound always gives higher weight lossHalf strength permanganate at 60 ºC gives weight loss equivalent to baseline
Click to edit Master title style
SEMs of Through HolesSolvent – Yes K2MnO4 – 65 g/l, NaOH – 32 g/l, Temperature – 60 ºC
Silent
Ultrasound
Solvent – Yes K2MnO4 – 33 g/l, NaOH – 32 g/l, Temperature – 60 ºC
Silent
Ultrasound
Click to edit Master title style
Effect of Ultrasound on Permanganate Etch in Desmear Process
Solder Float AssessmentExperimental RunsIsola 370 HR 4-Layer MLBHole size – 0.9 mm DiameterSolder Float – 1 X 260 ºC, 10 seconds
Run No Ultrasound
Permanganate
ICD rate (%)Temp. Conc. NaOH
ºC g/l g/l
Standard Kelan
DesmearNo 85 65 32 0.0
40 Yes60 65 32
0.0
42 Yes 60 33 32 0.0
Click to edit Master title style
Effect of Ultrasound on Permanganate Etch in Desmear Process
Conclusions
• Initial weight loss studies indicated that the application of ultrasound to the permanganate part of the PCB desmear process produced higher weight loss and would enable lower temperature and lower permanganate concentrations to be used.
• SEM examination of through holes confirmed these findings
• Applying ultrasound to the permanganate in a semi-production mode produced defect free PCBs at lower temperatures and lower permanganate concentrations
Click to edit Master title style
SUSONENCE
• Three year multi-partner project• Aims to produce industrial scale ultrasonic equipment for sustainable
surface modification• Target sectors - metal finishing and printed circuit board
Objectives
• Reduced use of toxic/ hazardous chemicals• Waste minimisation/ diversion from landfill• Reduced energy consumption• Reduced water consumption
Click to edit Master title style
The system is designed to be very flexible in its operation.
Applications • pre-treatment• Etching• Post treatment• Rinsing
The ultrasound tank is connected to a heater chiller which controls the temperature between 0 and 80ºC. Other tanks have a built in heater. An extraction system has been implemented.
Click to edit Master title style
Contact details
[email protected] +44 (0) 24 76 795 179Mobile +44 (0) 7706 955 901
http://www.coventry.ac.uk/research/research-directory/engineering/functional-materials/
Click to edit Master title stylewww.ctechinnovation.com
Stuart DalrympleTel: +44 (0)151 347 2958Email: [email protected]