an evaluation of sonochemical surface modification for ......annual conference. 5. th. september...
TRANSCRIPT
An Evaluation of Sonochemical
Surface Modification for Electronic Manufacture
Dr Andy Cobley
Prof. Tim Mason
The Sonochemistry
Centre at Coventry University
IeMRC
2nd
Annual Conference
5th
September 2007
Sonochemistry Centre at Coventry University “The Home of Sound Science”
AgendaAgenda1.Surface Modification in Electronic Manufacturing
Problems associated with traditional methods
2.What is SonochemistryAcoustic cavitation
Advantages for surface modification
3.Sonochemical Surface Modification of a High Tg
EpoxyWeight loss
Contact Angle
Roughness
Gloss
Adhesion SEM
4. Conclusions for High Tg
Epoxy
5. Other materials tested
6. Lean, Green and Clean Processing?
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Traditional Traditional ‘‘WetWet’’
Surface ModificationSurface Modification
Chemistry Time / min Temp / ºCSolvent Swell 5-15 65-85Rinse 2-6Rinse 2-6Permanganate Etch 5-15 75-85Rinse 2-6Rinse 2-6Neutralizer 3 RT-50Rinse 1-2Rinse 1-2
•Relatively long dwell times
•3 stage process
•High Temperatures required
•High energy costs
•Copious rinsing
•High water costs
Example Example --
DesmearingDesmearing
of PCBof PCB’’s or Adhesion Promotion of s or Adhesion Promotion of MIDsMIDs
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Traditional Traditional ‘‘WetWet’’
Surface ModificationSurface Modification
Substrates Chemistry HazardsPCBs, MIDs
other polymersSolvent Swell VOC, flammable
PCBs, MIDs other polymersAlkaline 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
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Traditional Traditional ‘‘WetWet’’
Surface ModificationSurface Modification SummarySummary
Traditional surface modification processes characterised by…..
•Long process times
•High temperature baths
•High water usage
•Hazardous chemistry
CAN SONOCHEMISTRY HELP ?
Sonochemistry Centre at Coventry University “The Home of Sound Science”
SonochemistrySonochemistryThe 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
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface ModificationSonochemical Surface Modification Acoustic Acoustic CavitationCavitation
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
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface ModificationSonochemical Surface Modification MicrojettingMicrojetting at a solid surfaceat a solid surface
surface cleaningdestruction of boundary layersurface activationimproved mass and heat transfer
boundary layer
solid surface
Collapse at or near a solid surfaceInrush of liquid from one side of the collapsing bubble
produces powerful jet of liquid targeted at surface
surface cleaningdestruction of boundary layersurface activationimproved mass and heat transfer
surface cleaningdestruction of boundary layersurface activationimproved mass and heat transfer
boundary layer
solid surface
Collapse at or near a solid surfaceInrush of liquid from one side of the collapsing bubble
produces powerful jet of liquid targeted at surface
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface ModificationSonochemical Surface Modification MicrojettingMicrojetting
at a solid surfaceat a solid surface
Prof. L.A. Crum, University of Seattle
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface ModificationSonochemical Surface Modification Generation of Oxidizing Species
Chemicals break down in the cavitation bubble
Sonochemical decomposition of water
H2 O →
Ho
+ OHo
Ho
+ O2
→
HO2o
HO2o
+ HO2
o →
H2 O2 + O2
OHo
+ OHo →
H2 O2
OHo
(Hydroxyl radical) –
short lived
HO2o (Perhydroxyl
radical) –
short lived
H2 O2 (Hydrogen Peroxide)
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface ModificationSonochemical 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
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface ModificationSonochemical Surface Modification of a High of a High TgTg
EpoxyEpoxy
IsolaIsola
370HR370HR
Tg (ºC)By DSC
180
Dielectric Constant (10 GHz)
3.92
Dissipation Factor (10 GHz)
0.0025
NB Values collected from from Isola
Data sheet
Sonochemistry Centre at Coventry University “The Home of Sound Science”
SonochemicalSonochemical
Experimental SetExperimental Set--upup20 kHz Ultrasonic probe
Water in
Water out
Water Jacket
Solution
Sample holder
Sample
Thermostat
•All experiments performed at 40 ºC
•Sonication
carried out in DI water
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Process FlowsProcess FlowsSonochemical1. Sonication40 ºC, 4,8,15,30 and 60 minutes2. Cold water rinse, 5 minutes3. DI water rinse, 1 minute4. Dry
Total process time –
10-
66 minutes
Swell and Etch(Rohm and Haas Electronic Materials Products)
1. Sweller
(Circuposit
3302)85 ºC, 10 minutes2. Cold water rinse, 5 minutes3. Cold water rinse, 5 minutes4. Etch (Circuposit
Promoter 3310)85 ºC, 10 minutes5. Cold water rinse, 5 minutes6. Cold water rinse, 5 minutes7. Neutraliser (3% H2
O2
, 3% H2
SO4
)RT, 3 minutes8. Cold water rinse, 3 minutes9. DI water rinse, 1 minute10. Dry
Total process time –
47 minutes
Sonochemistry Centre at Coventry University “The Home of Sound Science”
ResponsesWeight lossMaterial removed from substrate
SEMVisual examination of the surface after surface modification
Contact Angle
A measure of the wettability
of a surfaceRelated to surface energy of substrate
AdhesionTape test after electroless
copper
platingGrade 10 –
no metal removed by tapeGrade 0 –
all metal removed by tape
Gloss MeterMeasures % light reflected from a surface.Rougher the surface less light reflected
RoughnessStylus profilometerRa -
the arithmetic departure of the
roughness profile from the mean line
Sonochemistry Centre at Coventry University “The Home of Sound Science”
0 4 8 15 30 600.0000
0.1000
0.2000
0.3000
Wei
ght L
oss
(mg/
cm2 )
Time (minutes)
SonochemicalSonochemical
Surface Modification of Surface Modification of IsolaIsola
370HR370HR DI Water, 40DI Water, 40ººCC
Effect of Effect of SonicationSonication
Time on Weight LossTime on Weight Loss
•Weight loss increases with sonication
time –
ultrasound is removing material•Extended sonication
times produces weight loss approximately 50% of swell and etch technique
Swell and Etch -
0.6059 mg/cm2
Sonochemistry Centre at Coventry University “The Home of Sound Science”
0 4 8 15 30 6060.0
70.0
80.0
90.0
Con
tact
Ang
le (θ)
Time (minutes)
SonochemicalSonochemical
Surface Modification of Surface Modification of IsolaIsola
370HR370HR DI Water, 40DI Water, 40ººCC
Effect of Effect of SonicationSonication
Time on Contact AngleTime on Contact Angle
•Contact angle decreases with sonication
time –
suggests surface activation•Swell and Etch gives contact angle value of around 70º
-
surface activation similar to 30 minutes sonication
Swell and Etch -
71.6 º
Sonochemistry Centre at Coventry University “The Home of Sound Science”
0 4 8 15 30 600.3
0.4
0.5
Rou
ghne
ss (µ
m)
Time (minutes)
SonochemicalSonochemical
Surface Modification of Surface Modification of IsolaIsola
370HR370HR DI Water, 40DI Water, 40ººCC
Effect of Effect of SonicationSonication
Time on RoughnessTime on Roughness
• After 30 minutes sonication
a value of 0.5 is reached which appears to be a maximum•Swell and Etch process produced a relatively low value for roughness
Swell and Etch -
0.3977
Sonochemistry Centre at Coventry University “The Home of Sound Science”
0 4 8 15 30 600.5
1.0
1.5
2.0
Glo
ss (%
)
Time (minutes)
SonochemicalSonochemical
Surface Modification of Surface Modification of IsolaIsola
370HR370HR DI Water, 40DI Water, 40ººCC
Effect of Effect of SonicationSonication
Time on GlossTime on Gloss
•Gloss meter results are all very low •Gloss meter readings tended to drop with sonication
time -
minimum at 30 minutes•Swell and Etch sample had a reading of 1.9% suggesting a smoother topography.
Swell and Etch -
1.9%
Sonochemistry Centre at Coventry University “The Home of Sound Science”
0 4 8 15 30 605.0
6.0
7.0
8.0
9.0
10.0
Adh
esio
n (G
rade
)
Time (minutes)
SonochemicalSonochemical
Surface Modification of Surface Modification of IsolaIsola
370HR370HR DI Water, 40DI Water, 40ººCC
Effect of Effect of SonicationSonication
Time on Adhesion after Time on Adhesion after ElectrolessElectroless
CopperCopper
•Highest adhesion grading occurred with the sample sonicated
for 30 minutes •The control sample failed the tape test resulting in an adhesion
grade of 1
Swell and Etch -
1.0
Sonochemistry Centre at Coventry University “The Home of Sound Science”
IsolaIsola
370HR 370HR SEM Analysis SEM Analysis --
Magnification x 500Magnification x 500
As Recieved30 minutes Sonication
Exposed glass
No debris
Swell and Etch
Exposed glass
Debris
Sonochemistry Centre at Coventry University “The Home of Sound Science”
SonochemicalSonochemical
Surface Modification of Surface Modification of IsolaIsola
370HR370HR CONCLUSIONSCONCLUSIONS
1.
Surface modification of this high Tg
Epoxy can be achieved by the application of ultrasound through DI water at 40ºC
2.
Optimal sonication
time for adhesion is 30 minutes3.
30 minutes sonication
time also corresponds to highest
roughness and lowest gloss. SEM analysis shows glass exposure but no debris.
4.
2 and 3 suggest a rough, debris free surface is important for optimal adhesion
5.
Swell and Etch samples gave high weight loss, but roughness and gloss data suggest a smooth surface.
6.
SEM analysis indicates a lot of debris -
probably the reason for poor adhesion
7.
Swell and Etch samples may be over-etched
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface ModificationSonochemical Surface Modification Other materials testedOther materials tested
Cycolac
S705 –
ABS/PC
Noryl
HM4025 –
Polyphenylene
ester / polystyreneCourtesy of Moulded Circuits
Ceramic Material
Other materials under investigation:
Glass –
optical circuits
Coated ‘paper’
–
printed/plastic electronics
Sonochemistry Centre at Coventry University “The Home of Sound Science”
NorylNoryl
HM4025HM4025 DI Water, 40DI Water, 40°°CC
, 60 minutes, 60 minutes
Magnification x 500Magnification x 500
As received 20 kHz Ultrasonic Probe
Sonochemistry Centre at Coventry University “The Home of Sound Science”
CycolacCycolac
S705 ABS/PC S705 ABS/PC DI Water, 40DI Water, 40°°CC
, 60 minutes, 60 minutes
Magnification x 1000Magnification x 1000
As Received 20 kHz Ultrasonic Probe
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Ceramic Material Ceramic Material DI Water, 40DI Water, 40°°CC
, 60 minutes, 60 minutes
Magnification x 1000Magnification x 1000
AS received 20 kHz Ultrasonic Horn
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface ModificationSonochemical 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
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 DETAILSCONTACT DETAILS
[email protected] - +44 (0) 24 76 888 624
Mobile – 07706 955 901Fax +44 (0) 24 76 888173
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Sonochemical Surface ModificationSonochemical Surface ModificationProject funded by
Industrial Partners
MOULDED CIRCUITS LTD
Laminate supplied by………
Sonochemistry Centre at Coventry University “The Home of Sound Science”
Thank youThank you
Any Questions ?