Functional Nanocomposites Laboratory

은나노입자를은나노입자를 이용한이용한마이크로마이크로 contact contact 프린팅프린팅 및및 잉크젯잉크젯 프린팅프린팅

개요개요: : PCBPCB에에 회로를회로를 형성하는형성하는 기술로기술로 PhotolithographyPhotolithography가가 가장가장 많이많이 사사용되고용되고 있으나있으나, , 이이 기술의기술의 문제점과문제점과 한계를한계를 극복하기극복하기 위하여위하여, , Microcontact Printing Microcontact Printing 기술과기술과 잉크젯프린팅잉크젯프린팅 기술을기술을 사용한다사용한다. . 특히특히은노입자를은노입자를 이용하여이용하여 패턴을패턴을 형성한형성한 후후 200200이하의이하의 온도에서온도에서 용융용융결착시켜서결착시켜서 은은 회로를회로를 형성시킨다형성시킨다..

응용분야응용분야: : Display, Solar Cell, Packaging, Display, Solar Cell, Packaging, 전자파전자파 차폐코팅차폐코팅, , ESD(Electrostatic Discharge)ESD(Electrostatic Discharge)코팅코팅, FPCB Packaging, Embedded , FPCB Packaging, Embedded Systems Systems

참고문헌참고문헌: : •• Macromolecular Research, in press (2009).Macromolecular Research, in press (2009).•• European Polymer Journal, 44(10), 3116European Polymer Journal, 44(10), 3116--3121 (2008).3121 (2008).

Functional Nanocomposites Laboratory

Sintering and Consolidation of Silver Nanoparticleson Polyimide Substrate Films

Size effect of the melting temperature of NanoparticlesRH

TT

r

f

00

2

∆=−=∆ρ

σθθ

50 100 150 200 250

-0.25

-0.20

-0.15

-0.10

-0.05

Heat Flow (W/g)

Temperature (oC)

Tm of AgNP : 118 Dodecanethiol

detached point

: 105

Functional Nanocomposites Laboratory

Microcontact Printing of Silver Nanoparticels on PI Films

• High Concentration

• High conductivity

• No oxidation

• Low temperature

sintering process

• Reduction in material loss

• High productivity through

roll-to-roll process

• High quality pattern

for FPCB

• Good adhesive strength

between pattern and film

Ag nanoaprticles ink Ag nanoaprticles ink Microcontact Printing Microcontact Printing Flexible Printed Circuit Board Flexible Printed Circuit Board

Sintering Process or Ag nanoparticles

Nanoscale particles give an extremely large surface area, which have a high surface free energy to drive sintering at low temperature.

AgNP

Neck

Grain boundary

Pore

sintering

pressure

PI film Polymer stamp

pressure

PI film Polymer stamp+

AgNPAgNP

Functional Nanocomposites Laboratory

Sintering and Consolidation of Silver Nanoparticleson Polyimide Substrate Films

45

21

3

6

1. Surface diffusion

2. Lattice diffusion (from the surface)

3. Vapor transport

4. Grain boundary diffusion

5. Lattice diffusion (from the grain boundary)

6. Plastic flow

180 for 3 hrs

290 for 3 hrs

Functional Nanocomposites Laboratory

0 10 20 30 40 50 60

10-6

10-5

10-4

Specific resistance (Ωcm

)

Time (min)

300 , 1hr

8.1×10-6 Ωcm 0 10 20 30 40 50 60

10-6

10-5

10-4

Specific resistance (Ωcm

)

Time (min)

SEM image of Ag patterns SEM image of Ag patterns Specific electrical resistance Specific electrical resistance

1.9

9.6

300 , 1hr

8.1×10-6 Ωcm

OM images of silver nanoparticles patterns on polyimide films after heat treatment (a) 2 patterns and (b) 10 patterns

OM images of silver nanoparticles patterns on polyimide films after heat treatment (a) 2 patterns and (b) 10 patterns

Microcontact Printing of Silver Nanoparticels on PI Films

Functional Nanocomposites Laboratory

1µm

SEM image of polyimide film surface after the silver layer being peeled-off. The heat treatment temperature are (a) 180 , (b) 250 , (c) 270 and (d) 290 .

SEM image of polyimide film surface after the silver layer being peeled-off. The heat treatment temperature are (a) 180 , (b) 250 , (c) 270 and (d) 290 .

• The capillary force between the spherical silver particle and polyimide flat surface seems to induce deformation (dimples) of polyimide films in the rubbery state.

SEM Image of PI Film After Scotch Tape Test