characterization of mechanical properties of thin film using residual compressive stress

37
Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress 2004. 2. 16. Sung-Jin Cho, Jin-Won Chung, Myoung-Woon Moon and Kwang-Ryeol Lee Korea Institute of Science and Technolog y 미미미미 Workshop, 미미미 미미미 미미미미미

Upload: wynter-graves

Post on 03-Jan-2016

46 views

Category:

Documents


2 download

DESCRIPTION

Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress. 2004. 2. 16. Sung-Jin Cho, Jin-Won Chung, Myoung-Woon Moon and Kwang-Ryeol Lee Korea Institute of Science and Technology. 미세구조 Workshop, 강원도 평창군 피닉스파크. Residual Stress of Thin Films. - PowerPoint PPT Presentation

TRANSCRIPT

Page 1: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

2004. 2. 16.

Sung-Jin Cho, Jin-Won Chung, Myoung-Woon Moon and Kwang-Ryeol Lee

Korea Institute of Science and Technology

미세구조 Workshop, 강원도 평창군 피닉스파크

Page 2: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Residual Stress of Thin Films

• Thin films typically support very high stresses due to the constraint of the substrate to which they are attached

Page 3: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Residual Compressive Stress of DLC Film

Film Deposition

Page 4: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Telephone Cord Buckling

M.W.Moon et al , Acta Mater., 50 (2002) 1219.

Page 5: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Off-Piste Run in Hoghfügen

Page 6: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Buckling Configurations

Page 7: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Quantitative Analysis

K.-R. Lee et al , Diam. Rel. Mater., 2 (1993) 218.

Page 8: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

What can we do with this phenomenon?

• Can be a useful tool to estimate the fundamental interface toughness (adhesion) and the mechanical properties of thin films

Page 9: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

What can we do with this phenomenon?

1

E

For Isotropic Thin Films

Page 10: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Measurement of Residual Stress

f

s

s

s

d

dE

R

2

21

1

Curvature (R)

DsDf

Page 11: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

What can we do with this phenomenon?

1

E

For Isotropic Thin Films

Page 12: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

DLC Bridges by Micro Fabrication

DLC film Deposition ( on SiO2 )

DLC PatterningSiO2 Isotropic Wet Etching

Wet Cleaning

Strain Estimation

Page 13: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

C6H6, 10mTorr, -400V, 0.5m

150m

Microstructure of DLC Bridges

Page 14: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Strain of the Buckled Thin Films

xco

E

)1(

Z

X

2A0

2

2

2

2

11

2

1

2

2

o

x

x

A

dxx

W

x

W

cooA

E

2

1

ooA

E

2

1

Page 15: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Effect of Bridge Length

60 80 100 120 140 1600

40

80

120

160

200

E/(

1-)

(G

Pa)

Bridge Length (m)

m

Page 16: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Dependence of Film Thickness

0.0 0.3 0.6 0.9 1.2 1.50

40

80

120

160

200

E/(

1-)

(G

Pa)

Thickness (m)

Page 17: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

V

V V

V

DLC Bridges

Page 18: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Biaxial Elastic Modulus

0 100 200 300 400 500 600

0

50

100

150

200

SiO2 etching techniqueE

/(1-

) (

GP

a)

Negative Bias Voltage (V)

Page 19: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

DLC film Deposition

Cleavage along [011] Direction

Si Etching (by KOH Solution) Wet Cleaning

Strain Measurement

Preparation of Free Overhang

Page 20: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Free Overhang Method

• Biaxial elastic modulus

• Strain of the free overhang

2

0

)(1 A

E

20 )( A

Page 21: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

A0 / λof Free-hang at 546 nm

4 8 12 16 20 24

0.02

0.04

0.06

0.08

0.10

0.12

0.14

A0

/

Etching Depth (m)

I II III

a-C:H, C6H6 -400V

Page 22: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

5.6 ㎛ 11.3 ㎛

2 ㎛ 11 ㎛

Effect of Etching Depth

546 nm

55 nm

Page 23: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Elastic Modulus for Various Ion Energies

0 100 200 300 400 500 600 700 800

0

50

100

150

200

250

Pla

ne

Str

ain

Mod

ulus

(G

Pa

)

Negative Bias Voltage (V)

Nanoindentation t>1.0 ㎛

100 200 300 400 500 600

0

50

100

150

200

Bridge Method

Freehang Method

E/(1

-)

(GPa

)

Negative Bias Voltage (V)

Page 24: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Advantages of This Method

• Simple Method• Completely Exclude the Substrate Effect• Can Be Used for Very Thin Films

Page 25: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Nano-indentation

Substrate Effect is Significant.

The elastic strain field >> the plastic strain field

Substrate

Page 26: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Substrate Effect on the Measurement

0 50 100 150 200 250 300 350

100

200

300

400

500

600

700 500nm ta-C on Si 500nm ta-C on Al

CSM

Elas

tic M

odul

us (G

Pa)

Displacement (nm)0 50 100 150 200 250 300 350

100

200

300

400

500

600

700 200nm ta-C on Si 200nm ta-C on Al

CSM

Elas

tic M

odul

us (G

Pa)

Displacement (nm)

Page 27: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Advantages of This Method

• Simple Method• Completely Exclude the Substrate Effect• Can Be Used for Very Thin Films

Page 28: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

0 200 400 600 800 1000 1200

25

50

75

100

on Si on W / Si on SiO

2/ Si

Bia

xial

Ela

stic

Mod

ulus

(G

Pa

)

Thickness (nm)

a-C:H, C6H6 -400V

J.-W. Chung et al, Diam.Rel. Mater. 10 (2001) 2069.

ta-C (Ground)

Elastic Modulus of Very Thin Films

Page 29: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Biaxial Elastic Modulus

0 100 200 300 400 500 6000

50

100

150

200

Bia

xial

Ela

stic

Mod

ulus

(GP

a)

Thickness (nm)

0 50 100 150 200 250

0.5

1.0

1.5

2.0

2.5

3.0

Res

idua

l Com

pres

sive

Str

ess

(GP

a)

Vb / P1/2 (V/mTorr1/2)

20

233

166

100

Page 30: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

0 300 600 900 12001520

1530

1540

1550

1560

G-p

eak

Pos

ition

(cm

-1)

Thickness (nm)

233

166

100

20

Structural Evolution of DLC Films

Si Substrate

Si Substrate

Si Substrate

0 100 200 300 400 500 6000

50

100

150

200

Bia

xial

Ela

stic

Mod

ulus

(GP

a)

Thickness (nm)

J.-W. Chung et al, Diam.Rel. Mater., 11, 1441 (2002).

Page 31: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

0 100 200 300 400 500 6000

1

2

3

4

5

6

7

Res

idua

l Com

pres

sive

Str

ess

(GP

a)Negative Bias Voltage (V)

Residual Stress of ta-C film

Page 32: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

0 100 200 300 400 500 600 7000

100

200

300

400

500

600

700

800

900

Bia

xia

l Ela

stic

Mo

du

lus

(GP

a)

Thickness (nm)

Biaxial Elastic Modulus of ta-C film

Page 33: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Conclusions

• Can be a useful tool to estimate the fundamental interface toughness (adhesion) and the mechanical properties of thin films

Page 34: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

What can we do with this phenomenon?

• Can be a useful tool to estimate the fundamental interface toughness (adhesion) and the mechanical properties of thin films

Page 35: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Fundamental Adhesion

B fsT

B f sU

s f fs

B fs B s f

B B

T U

T U

22

2)1(3

B

B

B

ut

tE

22

2)1(3

B

B

B

ut

tE

Page 36: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

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)

Fundamental Adhesion

DLC on Glass

Page 37: Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress

Conclusions

• Can be a useful tool to estimate the fundamental interface toughness (adhesion) and the mechanical properties of thin films