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C-Tech Innovation Profitable Growth through Innovation

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.

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C-Tech Innovation Profitable Growth through Innovation

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  1. C-Tech Innovation Profitable Growth through Innovation Stuart Dalrymple Ultrasound as an enabling technology for sustainable electronic manufacturing

  2. Ultrasound as an enabling technology for sustainable electronic manufacturing Dr Andrew Cobley

  3. Agenda • 1.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

  4. Traditional ‘Wet Chemical’ Surface Modification • Hazardous Chemistry • VOC’s, carcinogens, corrosive • Environmental and health and safety legislation • High Waste Treatment costs

  5. Traditional ‘Wet’ Surface ModificationSummary • Traditional surface modification processes characterised by….. • Long process times • High temperature baths • High water usage • Hazardous chemistry CAN SONOCHEMISTRY HELP ?

  6. Sonochemistry The effect of sound on the chemistry of a solution

  7. Sonochemical Surface ModificationAcoustic Cavitation

  8. Microjetting/Microstreaming boundary layer solid surface Video courtesy of University of Twente, Netherlands. and Shimadzu Europa GmbH, Duisburg, Germany Acoustic Cavitation in a liquid NEAR A SURFACE UNSYMMETRIC COLLAPSE Inrush of liquid from one side of the collapsing bubbleproduces powerful jet of liquid targeted at surface • Thinning of diffusion layer • Surface Cleaning • Surface activation • Improved mass and heat transfer

  9. 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

  10. Sonochemical Surface Modification Original Research Concept Use ultrasound to make existing surface modification processes more ‘sustainable’ 3 year Platform study funded by • Reduce chemical concentrations • Reduce process times • Reduce temperatures

  11. Materials Tested Sonochemical Surface Modification Isola 370HR – Tg 180 ºC Ceramic Material Noryl HM4025 – Polyphenylene ester / polystyrene Courtesy of Moulded Circuits Cycolac S705 – ABS/PC

  12. 1 minute Sonication in Water, 20 kHz 1 minute HF Etch Sonochemical Surface Modification of Ceramic 30 minutes HF Etch 30 minutes Sonication in Water, 20 kHz

  13. 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

  14. Sonochemical Surface Modification in Water Optimization of Ultrasonic Frequency Noryl HM4025, 40 ºC, 30 minutes

  15. Sonochemical Surface Modification in WaterOptimization of Ultrasonic Intensity at 20 kHz Effect of Ultrasonic Intensity on Weight loss for Noryl HM4025 20 kHz, DI Water, 40 ºC, 15 minutes

  16. Sonochemical Surface Modification in WaterOptimization of Probe to Sample Distance Effect of Probe to Sample Distance on Weight Loss for Isola 370HR 20 kHz, 4.8 Wcm-2, DI Water, 40 ºC

  17. Sonochemical Surface Modification of ABSModified process After Sonication at 40 kHz As received

  18. 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

  19. High Efficiency Printed Circuit Board Processes HEPROC Effect of Ultrasound on Permanganate Etch in Desmear ProcessNine Month Feasibility Project Funded by the Technology Strategy Board (TSB)

  20. Desmear Process Permanganate – with/without ultrasound (vigorous stirring) Ultrasound – 20 kHz ultrasonic probe, Power 50 W, Probe to sample distance 5 mm

  21. Effect of Ultrasound on PCB DesmearIsola 370HR Laminate Baseline Baseline value obtained using - 65g/l KMnO4, 32g/l NaOH @ 85 ºC Ultrasound always gives higher weight loss Half strength permanganate at 60 ºC gives weight loss equivalent to baseline

  22. Solvent – Yes K2MnO4 – 65 g/l, NaOH – 32 g/l, Temperature – 60 ºC SEMs of Through Holes Silent Ultrasound Solvent – Yes K2MnO4 – 33 g/l, NaOH – 32 g/l, Temperature – 60 ºC Silent Ultrasound

  23. Effect of Ultrasound on Permanganate Etch in Desmear ProcessSolder Float Assessment Experimental Runs Isola 370 HR 4-Layer MLB Hole size – 0.9 mm Diameter Solder Float – 1 X 260 ºC, 10 seconds

  24. Effect of Ultrasound on Permanganate Etch in Desmear ProcessConclusions • 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

  25. 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

  26. 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.

  27. Contact details a.cobley@coventry.ac.uk Telephone +44 (0) 24 76 795 179 Mobile +44 (0) 7706 955 901 http://www.coventry.ac.uk/research/research-directory/engineering/functional-materials/

  28. www.ctechinnovation.com Stuart Dalrymple Tel: +44 (0)151 347 2958 Email: sd@ctechinnovation.com

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