UltraViolet (UV)-Curable Coatings for Aerospace Applications
Aerospace parylene coatings july 2012
description
Transcript of Aerospace parylene coatings july 2012
Alan Hardy – Military Market ManagerJuly , 2012
Parylene Coatings for Enhanced Reliability of Electronics
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Agenda
•Parylene
- What is it?
- Why coat with it?
- History
- Overview of Specialty Coating Systems
- How is it applied?
- Properties and benefits
•Adhesion Technologies
•Industries and Applications
•Conclusion
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• Dielectric strength
• Electrically conductive
• Antistatic
• Thermal insulation
• Heat dissipating
• Radiation shielding
• Moisture, chemical, fluid barrier
• Anti-stiction, low friction
• Seal or reduce microporosity
• Abrasion resistance
• Stabilizes components and structures
• Biostability and biocompatibility
Why Conformal Coat?
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Conformal Coating Material Considerations
• Freedom from byproducts
• Application temperatures
• Cure forces
• Conformability - uniformity
• Control of thickness
• Crevice penetration
• Regulation/Quality compliance
• Biostability/Biocompatibility
• Properties of the coating– Barrier capabilities
– Environmental stability
– Sterilizability and bio-acceptability
• Minimization of mechanical loading
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• A common generic name for a unique series of polymers based on p-Xylylene
POLY(PARA-XYLYLENE)
• A truly conformal, thin, optically clear, inert coating applied in a vacuum chamber at room temperature
• A non-line-of-sight coating that follows molecular level deposition process
• A chemically pure coating that does not use any catalysts or leachable materials
What is Parylene?
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Why Parylene?
• Completely conformal
• Ultra-thin and lightweight
• Free from pinholes and defects
• Moisture & chemical barrier
• High dielectric strength
• Chemical insolubility
• Dry film lubricity
• Particle immobilization
• Hydrophobicity
• Optically clear – colorless
• Biocompatible and biostable
• Chemically pure, inert and free of catalytic, plasticizer and solvent residues
• No outgassing
• No leachable ingredients
• No cure forces/stresses
• Environmentally friendly
• No thermal stresses during room temperature deposition
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History of Parylene
• Dr. WM Gorham at Union Carbide Corporation (UCC) in late 1940’s
– Proposed using powdered form of dimer … a laboratory curiosity
• Dr. Gorham announced the vapor deposition polymerization (VDP) process
– Coating process that bears his name patented in 1967
• Nova Tran Corp. purchased license agreement from UCC in 1971
– Made Parylene VDP a commercial success
• Union Carbide Corporation purchased Nova Tran Corp. in 1984
• Renamed Specialty Coating Systems in 1991
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SCS is the direct descendant of Union Carbide Corporation
– Unbroken transfer of technology and I.P. – Over 40 years of Parylene applications experience
SCS manufactures its own dimer, ensuring high quality materials
SCS - the global leader in Parylene coating solutions
– Parylene variants, coating center locations, process development, coating technologies, equipment design, regulatory support
• 11 worldwide coating centers
– Americas: Costa Rica and United States (5)– Asia: Japan and Singapore– Europe: Czech Republic, Ireland and United Kingdom
Specialty Coating Systems
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Parylene N
• High dielectric strength … 7,000 V@ 25 μm
• Maximum continuous service temperature … 60°C
• Short term (≤24 hrs.) maximum service temperature … 80°C
• Coefficient of Friction … 0.25
• Certifications
− IPC-CC-830, MIL-I-46058C and listed on the QPL− USP Class VI and ISO-10993 biological evaluations
Parylene Variants
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Parylene C
• High dielectric strength … 5,600 V@ 25μm
• Maximum continuous service temperature … 80°C
• Short term (≤24 hrs.) maximum service temperature … 100°C
• Excellent chemical resistance
• Lowest permeability to moisture and gases
• Coefficient of Friction … 0.29
• Certifications
− IPC-CC-830, MIL-I-46058C and listed on the QPL− USP Class VI and ISO-10993 biological evaluations
Parylene Variants
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Parylene Variants
Parylene D
• High dielectric strength … 5,500 V@ 25μm
• Maximum continuous service temperature … 100°C
• Short term (≤24 hrs.) maximum service temperature … 120°C
• Lowest elongation
• Coefficient of Friction … 0.31
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Parylene Variants
Parylene HT®
• High dielectric strength … 5,400 V@ 25μm
• UV stable
• Lowest dielectric constant & dissipation factor
• Highest continuous service temperature … 350°C
• Short term (≤24 hrs.) maximum service temperature … 450°C
• Coefficient of Friction … 0.13
• Certifications
− IPC-CC-830, MIL-I-46058C and listed on the QPL− USP Class VI and ISO-10993 biological evaluations
Parylene HT is a registered trademark of Specialty Coating Systems, Inc.
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Parylene Characteristics
Crevice Penetration
Parylene C ≈ 5 times the diameter
Parylene N ≈ 40 times the diameter
Parylene HT ≈ 50 times the diameterResults may vary depending on a number of factors
Acrylics – Spray or brush
Silicones – Spray or brush
Urethanes – Spray or brush
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Parylene Deposition Process
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Parylene Deposition
• Film grows one molecule at a time
• Coating thickness is controllable
- 500 angstroms to 75 microns
• Coating thickness is based on dimer quantity and chamber load
• Nominal coating rate is ≈ 5 microns/hour
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Parylene Deposition
• No cure forces
– No thermal reactions– No expansion or contraction
• Very high degree of penetration/conformity
– Under, inside, edges and sides
• No liquid phase
– No meniscus, no edge effects– Nothing to leach or outgas
Parylene Coating Liquid Coating
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SEMs courtesy of
E.E. Hui, UC Berkeley.
Parylene Characteristics
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Parylene Properties
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Parylene Electrical Properties
Properties Parylene N Parylene C Parylene HTDieletric Constant6 GHz 2.46 - 2.54 3.06 - 3.10 2.10 - 2.15Dissipation Factor6 GHz 0.0002 - 0.0010 0.0021 - 0.0028 0.0015 - 0.0020
Additional Data
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Improvement in Wire Lead & Bond Strength
• A bare 1 mil aluminum wire has a typical bond strength of 3 to 5.5 grams
• With a 1 mil coating of Parylene C over the wire, bond strength increases to between 60 and 70 grams
Wire-bond strength vs. Parylene C coating thickness on a hybrid-to-chip lead
0
10
20
30
40
50
60
70
80
0 5 10 15 20 25 30
Pull
Stre
ngth
(in
gram
s)
Coating Thickness (in microns)
Parylene C
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Parylene Barrier Properties
Water Vapor Transmission
Polymer N2 O2 CO2 H2
Parylene N 3 15.4 84.3 212.6
Parylene C 0.4 2.8 3 43.3
Parylene HT 4.8 23.5 95.4 –
Epoxy (ER) 1.6 4 3.1 43.3
Polyurethane (UR) 31.5 78.7 1,181 –
Silicone (SR) – 19,685 118,110 17,717
Gas Permeability at 25°C, (cc•mm)/ (m2•day•atm)a
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Circuit boards after 144-hour salt fog test, in accordance with ASTM B117- (03).
Parylene Barrier Properties
Uncoated Coated
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Parylene Solvent Resistance
Chemical Tested Parylene N Parylene C Parylene HT
10% Nitric Acid, RT 0.1 0.1 0.0
10% Nitric Acid at 75oC 0.2 0.1 0.0
70% Nitric Acid, RT 0.2 0.2 0.0
70% Nitric Acid at 75oC Brittle 1.8 1.2
10% Sulfuric Acid, RT 0.1 0.3 0.0
10% Sulfuric Acid at 75oC 0.2 4.1 0.0
95-98% Sulfuric Acid, RT 0.2 0.4 0.0
95-98% Sulfuric Acid at 75oC 5.3 5.1 2.8
% Swelling
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Parylene Properties
0
1
2
3
4
Effe
ctiv
enes
s R
atin
g
Parylene N Parylene C Parylene HT Filter Cotton Duck
Test Samples
7 days
14 days
21 days
28 days
Rating: 0 = None
1= Traces of growth (less than 10%)
2= Light growth (10-30%)
3= Medium growth (30-60%)
4= Heavy growth (60% to complete coverage)
Test Method: ASTM G-21
Microorganism Resistance
Tested in accordance with Mil-STD 202, Method 302, test condition B (Temp: 650C, RH: 90-96%)
Moisture Resistance
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Thermal Characteristics
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0
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4
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10
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0 100 250 500 1000 1250 1500 2000
Visu
al c
olor
, cha
lk, c
rack
ratin
g [S
cale
: 0 -
Very
poo
r, 10
-Ex
celle
nt]
UV exposure time (hrs)
Parylene C
Parylene HT
UV Stability
Parylene films were exposed to radiation from a bank of fluorescent lamps using the following test parameters:
- Device used: QUV - Type of test: Accelerated weathering- Test method: ASTM 154 - Irradiance: 0.77 Watts per square meter - Source: UVA 340 lamp
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Prediction of End of Useful Life
Parylene Types
150oC 135oC 80oC
Parylene HT
~ 40 yrs.~ 100 yrs.
>100 yrs.
Parylene C
~ 24 hours
~ 70 hours
~ 10 yrs.
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10
100
1000
10000
100000
1000000
10000000
1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3
Log
Tim
e to
Fai
lure
(hrs
)
103/T Ko
Arrhenius Plot: Parylene HT vs. Parylene CLog Time to Failure vs. Reciprocal Absolute Temperature
(Failure: reduced elongation and tensile strength)
150oC
80oC
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Agenda
•Parylene
- What is it?
- Why coat with it?
- History
- Overview of Specialty Coating Systems
- How is it applied?
- Properties and benefits
•Adhesion Technologies
•Industries and Applications
•Conclusion
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Adhesion Considerations
• Adhesion effects all types of applications
− Aerospace− Automotive− Electronics− Medical− Military
• Properties impacted by poor adhesion
− Electrical insulation− Chemical resistance− Corrosion protection− Environmental stress protection − Moisture resistance
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• Physical and chemical nature of substrate
• Solder masks
• Cleanliness of substrate
– Manufacturing and human residues
– Particle contamination
Factors Affecting Adhesion
Particle was not removed before Parylene coating and is now “captured”
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• Mode of coating - solution, vapor, plasma
• Cure forces
• Stresses in the coating
• Nature of coating material and coating formulation
• Primer and adhesion promotion
– Chemical – Plasma– Abrasion
Factors Affecting Adhesion
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Corrosion of a PCB
Delamination, chipping
Blister
Adhesion Issues
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Coating adhesion failure leading to delamination and/or corrosion
No clean flux residue and Corrosion on a PCB
Adhesion Issues
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Failed assembly with spots of poor adhesion Good assembly with strong adhesion (no spots)
Adhesion Issues
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AdPro Plus®
Chemical compound applied to a variety of metallic and plastic substrates (e.g., Stainless Steel, Cobalt-Chromium, Copper, Gold, Iridium, Nitinol, Platinum, Solder, Tin, Titanium, Tungsten, Aluminum, Nickel, Chromium, Brass, Polycarbonate, etc.) as a tie layer prior to the application of Parylene coating.
AdPro Poly®
Chemical compound applied to a variety of polymeric substrates (e.g., Polyimide, Epoxy, Acrylic, EPDM, etc.) as a tie layer prior to the application of Parylene coating. AdPro Plus and AdPro Poly are a registered trademarks of Specialty Coating Systems, Inc.
Latest Developments in Adhesion Promotion Technologies
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Adhesion Promotion Technologies
0
1
2
3
4
5
Stainless Steel(Mirror like finish
#8), 24 hrs@50%RH
Stainless Steel(Mirror like finish
#8), 48 hrs@50%RH
Stainless Steel(Mirror like finish
#8), Autoclave125C-1 hr
Titanium AlloyGrade 5 (Mil
Finish), 24 hrs@50%RH
Titanium AlloyGrade 5 (Mil
Finish), 50 hrs@50%RH
Titanium AlloyGrade 5 (Mil
Finish), Autoclave125C-1 hr
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2.2
0
4.7 4.7
0
4.8 4.8 4.8 4.8 4.8 4.8
Silane A-174 AdPro Plus
AST
M D
335
9-2,
Met
hod
B (0
=Poo
r, 5
=Exc
elle
nt)
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Adhesion Promotion Technologies
0
1
2
3
4
5
24 hrs @50%RH Autoclave 125C-1 hr
0 0
1.9
3.2
4.9 4.9
Silane A-174 AdPro Plus® AdPro Poly®
ASTM
D 3
359-
2, M
etho
dB
(0=P
oor,
5=E
xcel
lent
)
Polyimide (Kapton) Substrate
DuPont™ and Kapton® are trademarks or registered trademarks of E.I. du Pont de Nemours and Company.
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• AdPro Plus … solves adhesion challenges for difficult metallic and plastic substrates
• AdPro Poly … a new system that solves adhesion challenges for Polyimide substrates
• Both enhance the reliability of miniaturized and advanced components in all markets
Courtesy of DuPont.
Adhesion Promotion Technologies
DuPont™ and Kapton® are trademarks or registered trademarks of E.I. du Pont de Nemours and Company.
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MIL–I–46058 Specification
2011 QPL Listing
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SCS Certification AS/EN/JSQ9100:2009 – Rev C
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SCS Parylene C-UVF™
Introducing
SCS Parylene C-UVF is a trademark of Specialty Coating Systems, Inc.
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Industries and Applications
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Mass air temperature and pressure sensors
Emission sensors
Tire Pressure Monitoring Systems (TPMS)
Diesel fuel heaters
O-rings, seals and engine gaskets
Fuel cell and hybrid electronic systems
Engine electronics
MEMS sensors
Automotive Coating Applications
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Cardiac assist devices and components
− ICDs, pacemakers, VADs
Drug delivery devices
− Stents, inhalers (MDI, DPI, nasal)
Cochlear and intraocular implants
Catheters
Neurostimulators
Gastric balloons and cuffs
Endotracheal tubes
Laboratory devices
Printed circuit boards
Medical Device Coating Applications
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Wind power
Solar/photovoltaic
Energy harvesting
Hydropower
Geothermal
Renewable Energy Coating Applications
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• Video displays
• Electronic billboards
• Marine lighting
• Transportation signage
• Outdoor illumination
• Vehicle lighting
• Commercial refrigeration
• Aviation lighting
LED Coating Applications
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• Printed circuit boards
• MEMS wafers
• Probes / pins
• Rotors / stators
• Components
– Metal– Brackets
• Cables
• Ferrite cores
Electronics Coating Applications
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Military/Commercial
MEMS
Sensors
Circuit card assemblies
Motor components
Power supplies
Backplanes
Elastomeric parts
Aerospace
Spacecraft and satellite electronics
Cameras and assemblies
International Space Station remote arm components
Space Shuttle and International Space Station lab equipment
Military/Aerospace Coating Applications
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Advanced Parylene Applications
Check valve
Electrolysis pumpIn-channel check
valve
Parylene channel
Micro pump
Reaction chamber or reservoir
100 mMicro Active Valve
Thermal Flow
Sensor
Images courtesy of Dr. Y. C. Tai, Caltech.
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Conclusion
Parylene ultra-thin conformal coatings are being used more than ever to protect devices and components and enhance the reliability of today’s and tomorrow’s innovative technologies.
• Ultra-thin and conformal• Complete encapsulation• No liquid phase• No cure forces• Excellent moisture, chemical and
electrical properties • Low coefficient of friction• Exceptional thermal stability• Superior UV stability• Biocompatible and biostable
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Thank you