Parylene coatings for enhanced reliability of...

Parylene coatings for enhanced reliability of electronics

Alan Hardy, Electronics Market Manager

SEMICON Taiwan2011

September 9, 2011

2SEMICON Taiwan2011 – September, 2011

Agenda

•Parylene

- History

- Overview of Specialty Coating Systems

- What is it?

- Why coat with it?

- How is it applied?

- Properties and benefits

- Industries and applications

•Adhesion Technologies

•Advanced Parylene Applications

•Conclusion

•Questions & Answers

SEMICON Taiwan2011 – September, 2011


History of Parylene

• Dr. WM Gorham at Union Carbide Corporation (UCC) in late 1940’s

• 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


SCS is the direct descendant of Union Carbide Corporation

– Unbroken transfer of technology and I.P. – Over 40 years of Parylene applications experience

SCS - the global leader in Parylene coating solutions

– Parylene variants, coating center locations, process development, coating technologies, equipment design, regulatory support

• SCS controls its own dimer source, quality and formulation

Specialty Coating Systems


• 11 Worldwide Centers

– North America (5)– Costa Rica– United Kingdom– Ireland– Czech Republic– Japan– Singapore

• All coating centers use global Manufacturing Standard Procedures(MSPs) and quality standards

• Multiple locations enable SCS to react to changes in requirements, volume ramp-up or natural disasters

SCS Around the World


• 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?


Conformal Coating Material Considerations

• Freedom from byproducts

• Application temperatures

• Cure forces

• Conformability - uniformity

• Control of thickness

• Crevice penetration

• Regulatory/Quality compliance

• Biostability/Biocompatibility

• Properties of the coating

– Barrier capabilities

– Environmental stability

– Sterilizability and bio-acceptability

• Minimization of mechanical loading


• 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?


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


Parylene Variants


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


Parylene C

• High dielectric strength … 5,600 V@ 25μm



• Excellent chemical resistance

• Lowest permeability to moisture and gases


• Certifications

− IPC-CC-830, MIL-I-46058C and listed on the QPL− USP Class VI and ISO-10993 biological evaluations

Parylene Variants


Parylene Variants

Parylene D




• Lowest elongation



Parylene Variants

Parylene HT®


• UV stable

• Lowest dielectric constant & dissipation factor

• Highest continuous service temperature … 350°C



• 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.


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

16TECH BRIEFS WEBINAR – DEC. 2010

Parylene Deposition Process


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


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


SEMs courtesy of

E.E. Hui, UC Berkeley.

Parylene Characteristics


Parylene Properties


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


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 Strength (in gram

s)

Coating Thickness (in microns)

Parylene C


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


Circuit boards after 144-hour salt fog test, in accordance with ASTM B117- (03).

Parylene Barrier Properties

Uncoated Coated


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


Parylene Properties

0

1

2

3

4

Effe

ctiv

enes

s Ra

ting

Parylene N Parylene C Parylene HT Filter Cotton Duck

Test Samples

7 days14 days21 days28 days

Rating: 0 = None1= 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


0

2

4

6

8

10

12

0 100 250 500 1000 1250 1500 2000

Visua

l color, cha

lk, crack ra

ting

[Scale: 0

‐Ve

ry poo

r, 10

‐Excellent]

UV exposure time (hrs)

Parylene C

Parylene HT

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

UV Stability


Agenda

•Parylene

- History

- Overview of Specialty Coating Systems

- What is it?

- Why coat with it?

- How is it applied?

- Properties and benefits

- Industries and applications

•Adhesion Technologies

•Advanced Parylene Applications

•Conclusion

•Questions & Answers


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


• 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”


• 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


Corrosion of a PCB

Delamination, chipping

Blister

Adhesion Issues


Failed assembly with spots of poor adhesion Good assembly with strong adhesion (no spots)

Adhesion Issues


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


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 (MilFinish), 24 hrs@50%RH

Titanium AlloyGrade 5 (MilFinish), 50 hrs@50%RH

Titanium AlloyGrade 5 (Mil

Finish), Autoclave125C‐1 hr

1

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

ASTM D 335

9‐2, M

etho

dB (0=P

oor, 5=Excellent)



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 335

9‐2, M

etho

dB (0=P

oor, 5=Excellent)

Polyimide (Kapton) Substrate

DuPont™ and Kapton® are trademarks or registered trademarks of E.I. du Pont de Nemours and Company.


• 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.


DuPont™ and Kapton® are trademarks or registered trademarks of E.I. du Pont de Nemours and Company.


Industries and Applications


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


Wind power

Solar/photovoltaic

Energy harvesting

Hydropower

Geothermal

Renewable Energy Coating Applications


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


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


• Video displays

• Electronic billboards

• Marine lighting

• Transportation signage

• Outdoor illumination

• Vehicle lighting

• Commercial refrigeration

• Aviation lighting

LED Coating Applications


• Printed circuit boards

• MEMS wafers

• Probes / pins

• Rotors / stators

• Components

– Metal– Brackets

• Cables

• Ferrite cores

Electronics Coating Applications


Chip integration onto flexible Parylene electrodes

Images courtesy of Dr. Y. C. Tai, Caltech.

Advanced Parylene Applications

Parylene/Platinum retinal implant electrodes


Parylene Etching

Anisotropic profile of 55 µ Parylene

Anisotropic profile of 10 µ Parylene

ICP etch recipes for low temperature (5ºC) Parylene etching

Reference: A HIGH ASPECT RATIO, FLEXIBLE, TRANSPARENT AND LOW-COST PARYLENE-C SHADOW MASK TECHNOLOGY FOR MICROPATTERNING APPLICATIONSBy: S. Selvarasah1, S. H. Chao, C.-L. Chen, D. Mao, J. Hopwood, S. Ryley, S. Sridhar, A. Khademhosseini, A. Busnaina, and M. R. Dokmeci, Shadow Mask Transducers 2007

Etching Method ParylenePlasma (200 mT, 400W) 0.19 µm/min

RIE (100 sccm, 200mT, 400W) 0.56µm/min

DRIE (60 sccm, 23mT, 800W) 0.77µm/min


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


Thank you for attending


Specialty Coating Systems

• Contacts

– Mr. Hoon Keat, SCS, SingaporeTel: 65. 6862. 8687; Email: [email protected]

– Mr. Alan Hardy, SCS, Indianapolis, USA Tel: 317. 244. 1200 x 261; Email: [email protected]

Visit Booth 3040 for more information onParylene and Specialty Coating Systems

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