Effect of Filler Surface Modification Effect of Filler Surface Modification on the Dielectric Properties of Highon the Dielectric Properties of High--kk

Composite MaterialsComposite Materials

Lanla Yilla, Lanla Yilla, JiongxinJiongxin Lu, C. P. WongLu, C. P. Wong

School of Materials Science & EngineeringSchool of Materials Science & EngineeringNSF Packaging Research CenterNSF Packaging Research CenterGeorgia Institute of TechnologyGeorgia Institute of Technology

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

IntroductionIntroduction•• Embedded passivesEmbedded passives

•• Materials prerequisites Materials prerequisites –– High dielectric constant (K)High dielectric constant (K)

–– Low dielectric lossLow dielectric loss–– PCB compatible: Low process temperature (<200 PCB compatible: Low process temperature (<200 ººC)C)

tA

C r0εε=

Embedded Capacitors

Embedded Resistors

Micro ViaEmbedded Inductors

Copper Layer

Dielectric Layer

Surface Mount Device(BGA/CSP/FC)

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

Materials for embedded capacitorsMaterials for embedded capacitors

•• Ceramic materialsCeramic materialse.g. BLC (boundary layer capacitors) and MLCC (multilayer ceramie.g. BLC (boundary layer capacitors) and MLCC (multilayer ceramic c

capacitors)capacitors)

•• CeramicCeramic--metal compositesmetal compositese.g. BaTiO3e.g. BaTiO3--Ni Ni

•• PolymerPolymer--ceramic compositesceramic compositese.g. e.g. BaTiOBaTiO33/epoxy /epoxy

•• PolymerPolymer--conductive filler compositesconductive filler compositese.g. Ag/epoxye.g. Ag/epoxy

•• AllAll--organic compositesorganic compositese.g. PANI/PU, PANI/epoxye.g. PANI/PU, PANI/epoxy

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

PolymerPolymer--conductive filler compositesconductive filler composites

•• conductorconductor--insulator insulator percolativepercolative system as highsystem as high--K K materialsmaterials–– Scaling theoryScaling theory

–– AdvantageAdvantage•• UltraUltra--high dielectric constanthigh dielectric constant•• Lower filler loadingLower filler loading•• Balanced mechanical properties including high adhesion strengthBalanced mechanical properties including high adhesion strength

–– DisadvantageDisadvantage•• High dielectric lossHigh dielectric loss•• Narrow processing windowNarrow processing window

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

ObjectivesObjectives

•• Control the dielectric loss of polymerControl the dielectric loss of polymer--conductive filler conductive filler composites by modifying the properties of conductive composites by modifying the properties of conductive fillerfiller

•• Study the effect of carbon black surface treatment with Study the effect of carbon black surface treatment with inorganic coating on the dielectric behavior of ultrahigh k inorganic coating on the dielectric behavior of ultrahigh k carbon black composites. carbon black composites.

•• Investigate the filler surface treatment on the dielectric Investigate the filler surface treatment on the dielectric properties of polymerproperties of polymer--conductive filler compositesconductive filler composites

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

ApproachesApproaches

•• CoreCore--shell structureshell structure

•• Inorganic coating of carbon black particlesInorganic coating of carbon black particles•• SilaneSilane coupling agent treatment of metal coupling agent treatment of metal nanoparticlesnanoparticles

Organic/Inorganic Shell

Metal Core

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

Effect of filler typeEffect of filler type

0.0410.468Df

16154conductive

K

Ni/polymerCu/polymerAg/polymermetal/polymer

Dielectric properties of metal/polymer composites containing 10 vol.% various types of conductive filler (@ 10 kHz)

•• the K and the K and DfDf of Cu and Ni composites were both low due to the less of Cu and Ni composites were both low due to the less conductive properties and thicker oxide layer. conductive properties and thicker oxide layer.

•• Ag as selected for further investigation since its highest conduAg as selected for further investigation since its highest conductivity ctivity could render the lower percolation threshold and thus lower fillcould render the lower percolation threshold and thus lower filler er loading to maintain better adhesion and mechanical properties ofloading to maintain better adhesion and mechanical properties ofthe composites.the composites.

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

Having a blast collecting DataHaving a blast collecting Data

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

Filler treatmentFiller treatment

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

Thermal propertiesThermal properties

50 100 150 200

Temperature (oC)

20 wt.%152oC

94.5oC

50 100 150 200 250

Temperature (oC)

40 wt.%138.3oC

74.3oC

Ag/polymer composites silane coupling agent treated Ag/polymer composites

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

Effect of filler loadingEffect of filler loading

4 6 8 10 12 14 16 18 20

100

1000

10000

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

filler loading (wt.%)

DfK

Dielectric properties of Ag/polymer composites with various filler loadings (@ 10 kHz)

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

Effect of filler loadingEffect of filler loading

Dielectric properties of silane coupling agent treated Ag/polymer composites with various filler loadings (@ 10 kHz)

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

Effect of processing methodEffect of processing method

0.0010.0370.687.4315%

0.0020.0320.595.810%

SD DfDfSD KK

0.180.1981.517.6415%

0.170.1721.56.1310%

SD DfDfSD KK

Improved processing method

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

SummarySummary•• Surface modification of inorganic coating provide the carbon blaSurface modification of inorganic coating provide the carbon black ck

particles completely new characteristics. particles completely new characteristics.

•• Similarly, Similarly, silanesilane coupling agent treatment of Ag coupling agent treatment of Ag nanoparticlesnanoparticles could could also also

•• Improved processing method could render better film uniformity Improved processing method could render better film uniformity and thus more consistent data in dielectric study. Thinner film and thus more consistent data in dielectric study. Thinner film achieved using spinachieved using spin--coating method could increase the capacitance coating method could increase the capacitance density. density.

•• Thinner thickness and lower content of inorganic coatings are Thinner thickness and lower content of inorganic coatings are expected to improve the dielectric constant of the composites.expected to improve the dielectric constant of the composites.

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

Future workFuture work•• Try to achieve the ideal thickness and content of inorganic/orgaTry to achieve the ideal thickness and content of inorganic/organic nic

coating on the fillers to balance the dielectric properties.coating on the fillers to balance the dielectric properties.

•• Other electrical property study such as leakage current and Other electrical property study such as leakage current and breakdown voltage.breakdown voltage.

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

The Greatest and most wonderful MentorThe Greatest and most wonderful Mentor

School of Materials Science & Engineering, Georgia Institute of Technology07/12/2006

AcknowledgementsAcknowledgements

•• Sincere thanks and gratitude to Sincere thanks and gratitude to JiongxinJiongxin Lu Lu for all her helpfor all her help•• Thanks to Dr. Wong for allowing me the Thanks to Dr. Wong for allowing me the previledgepreviledge to work with his teamto work with his team•• Thanks to Jack for pairing me with Justin (Thanks to Jack for pairing me with Justin (JiongxinJiongxin))•• Thanks for making me feel welcome all group membersThanks for making me feel welcome all group members