Key Idea

For elastically isotropic thin film

Strain

Biaxial Elastic Modulus

2

0

)(1 A

E

20 )(A

1

E

Evaluation of Elastic Property of Thin Films by MEMSEvaluation of Elastic Property of Thin Films by MEMS

100 200 300 400 500 600

0

50

100

150

200

Bridge Method

Freehang Method

E/(

1-)

(G

Pa)

Negative Bias Voltage (V)

0.0 0.2 0.4 0.6 0.8 1.0

25

50

75

100

on Si on W on SiO

2

Biax

ial E

last

ic M

odul

us (G

Pa)

Thickness(m)

Free-hang

Bridge

Results

T : Elastic energy

U : Bending strain energy

Δγ : Surface energy

=(- fs+ fv+ sv)

fsT

svfvU

22

2)1(3

B

B

B

ut

tE

BB UT Buckling under Residual Compressive Stress & Energy Balance

Fundamental Adhesion Energy Fundamental Adhesion Energy MeasurementMeasurement

0.22 0.24 0.26 0.28 0.30 0.32 0.34 0.36-10

-5

0

5

10

15

20

25

30

(J

/m2 )

Thickness(m)100 200 300 400 500 600 700

-5

0

5

10

15

20

25

30

(J

/m2 )

Negative Bias Votage(V)

Results

Mirror

Mirror

Mirror

He-Ne laser

PSD

Beam Splitter

Chamber

• Step-

•Motor

•5Interface

System He-Ne laser : 632.8nm

Step-motor : 1 rpm

Lens FL : 500mm

PSD : S1300 (13×13mm)

In-situ stress measurement with temperature variation

i.e. Stress relaxation mechanism.

In-situ stress measurement under various environments

i.e. Stress vs. Humidity

In-situ Stress In-situ Stress MeasurementMeasurement

Residual stress versus. DC bias voltageIn Filtered Cathodic Arc Deposition

Principle Measurement of curvature Results

Residual Stress Residual Stress MeasurementMeasurement

Curvature (R)

dsdf

f

s

s

s

d

dE

R

2

216

1

Assumptions

1.The bending displacement is small compared with the thickness of the substrate

2. For a very thin deposit. ( ds << df )

dx

dsinθ

dx

dθcosθ

d

dθ

R

1K

I-V Curve F-N Plot

Emission Pattern from Vitreous Carbon

Keithley 6517Electrometer

SRS PS350Power Supply

x

y

ze

Anode

Cathode

CCDViewing System

ComputerInterface

3-D Manipulator

I-V Curve & Fluctuation Measuring System

Viewing System

SRS PS350Power Supply

Keithley 6517Electrometer

Phosphor coated ITO-glass

Cathode

Spacer

CCD

Emission Behavior from Vitreous Carbon

Emission Pattern Observing System

e

Visible Light

Current-Voltage Current-Voltage MeasurementMeasurement

Friction Behaviors of Pure DLC and Si-DLC in Ambient Environment

Ft

Ball

Film

Substrate

Ball On Disc Type TribometerBall On Disc Type Tribometer Results

n

t

F

F

Principle

Ft : Tangential Force Fn : Normal Force

Friction Coefficient

Fn

Substrate

Sessile-drop

l

sls

s : Substrate tension

l : Liquid tension

sl : Interface tension

Contact angle

Effects of CF4 Plasma Treatment of DLC Films

p : Polar componentd : Dispersive component

)cos1( lds

dl

ps

pl

High Surface Energy Low Surface Energy

Surface Energy Surface Energy MeasurementMeasurement

Results Principle

(a)

5N

Fractures morphology of DLC films(a) DLC on Tool Steel

(b) DLC on Tool Steel with W interlayer

Visual examination of the scratch to determine the critical load Fc that causes adhesion failure

Analysis of emission of acoustic signals that are small in magnitude when the film adheres at low load

Adhesion Measurement Adhesion Measurement Scratch testerScratch tester

Principle Results

(b)