1

NO.1

Improved Resolution of Thick Film Resist

(Effect of Development Technique)

Yoshihisa Sensu, Atsushi Sekiguchi and Yasuhiro Miyake

Litho Tech Japan Corporation

2-6-6 Namiki, Kawaguchi, Saitama, 332-0034, Japan

2

NO.2

(DNQ)Si 24

Q4000

N2

MEMS(Micro Electro Mechanical Syatems)TAB(Tape Bonding)

COG(Chip On Glass)CSP(Chip Scale Package)

[1]IC

[2]

[3]

Q4000[4]

RDA[5]

SOLID-C[6]

N2

3

NO.3

2.

2.1

(DNQ)

N2

N2

N2N2

N2

N2

2.2

(1)

Q4000 Q4000

[4]

RDA[5]

SOLID-C[6]

Litho Spin Cup[4]

23.731.7

() Si

24m

1107 15

30 [3]

(2)

Dipping Development ( DD )

(a)

Step Puddle Development ( SP )

(b)

100rpm 5 295 3

Vibration Development ( VD )

4

NO.4

(c)

50Hz 50m

Reverse Development ( RD )

(d)

(3)

Q4000 Quintel

TMAH

()23 15

10m 3.5(LineSpace11)i

10m 11 (Eop)

(4)

RDA[5] 950nm

Q4000

TMAH

SOLID-C[6]

[7] NA0.1

0.999 11

10m 4.0(LineSpace11)

10m 11 (Eop)

(5)

13 35

N2 N2

[8]

(6)

23

3.

3.1

SP 3.5mVD 4.0mDD 4.0m

RD 4.0mSP 4

5

NO.5

SP VD DD RD

RD

SP VD DD

RD

3.2

[9](

: tan)(Eth)

tanSP 3.4VD 2.9DD 2.3

RD 1.3 15

SP 14.6VD 8.7DD 8.0 RD 3.0 tan

15 (Eth)

SP 361.5mJ/cm2VD 377.4mJ/cm2DD

455.7mJ/cm2 RD 510.4mJ/cm2 SP

4.

4.1

SP VD DD RD

SP VD

DD RD SP

R(E) R E

SP VD DD

RD

4.2

350mJ/cm2

700mJ/cm2

(Activation energy) Frequency factor Kd

[10]

2ln

RTE

dTkd d = (1)

6

NO.6

E (kcal/mol)T (K)Kd(S-1)

350mJ/cm2 SP 29.97kcal/molVD 11.25kcal/mol

DD 4.41kcal/mol RD 1.14kcal/mol SP VD

DD RD

N2RD DD

) N2

N2 RD N2

SP VD

N2 (Eth)

350mJ/cm2 N2 SP VD

DD RD

() N2

DD RD SP

RD

() N2

N2 700mJ/cm2

DD VD

N2

N2 N2

N2

N2 N2

[8]

Z Z0 e(-E/RT)

23 1ml N2

1923

10554.2100029608204.0

102023.6=

==RTNn (2)

N Avogadro R (l atm/deg mol)T K

1sec N2 Z0

5.022

0 2

=MRTnZ (3)

n 1ml N2 N2(cm)M N2

7

NO.7

Z

RTE

eZZ

= 0 (4)

E (kcal/mol)

N2

350mJ/cm2 SP 4.60106molecule/secVD 3.061020molecule/sec

DD 3.441025molecule/sec RD 8.941027molecule/sec

N2

N2

350mJ/cm2 700J/cm2

350mJ/cm2 N2

4.3

SP VD SP SP VD

2.6mg/ml 5.5mg/ml

SP N2

5.

SP VD DD RD

N2N2

N2 N2

(SP VD

)(DD RD N2

N2

8

NO.8

N2

Q4000

Quintel Jeffrey Lane

SIGMA-C Dr. Christian K. Kalis

[1] R. Arai, "Exposure machine for the magnetic head, " Electric Parts and Materials,

pp. 84-89, Feb. 2000. [2] Y. Shibayama, and M. Saito, " Influence of Water on Photochemical Reaction of

Positive-Type Photoresist, " J. Appl. Phys. , vol.29, pp. 2152-2155, Oct. 1990. [3] , , , " , "

(C), vol. J85-C, no. 4, pp. 260-268, Apr. 2002. [4] Y. Sensu, A. Sekiguchi, and Y. Miyake, : Improved Resolution of Thick Film

Resist (Effect of Development Technique), Proc. SPIE, vol. 4690, pp. 861-882, Mar. 2002.

[5] A. Sekiguchi, C. A. Mack, Y. Minami, and T. Matsuzawa, " Resist Metrology for Lithography Simulation, Part 2 : Development Parameter Measurements, " Proc. SPIE, vol. 2725, p. 49, Mar. 1996.

[6] Erddmann A, Henderson C. L, Willson C. G, Henke W, " Influence of optical nonlinearities of photoresists on the photolithographic process : Applications, " Proc. SPIE, vol. 3048, pp. 114-124, Mar. 1997.

[7] Y. minami, A. Sekiguchi, " Deforcus Simulation Using Observed Dissolution Rate in Photolithography, " Electronics and Communications in Japan, Part 2, vol. 76, No. 11, pp. 106-115, Nov. 1993.

[8] , , " , " pp. 37-39, , , 1993.

[9] T. Kokubo, " History of Research and Development for Positive Photoresist, " Fuji Film Research and Development, No. 34, pp. 21-31, 1989.

[10] , , , " , " pp. 278-307, , , 1967.

9

(tan)(Eth)

Table 1 Development contrast (tan), values, and Eth for the different development

methods.

Development Method tan value Eth(mJ/cm2) Eop(mJ/cm2)

SP Method 3.4 14.6 361.5 540.0

VR Method 2.9 8.7 377.4 550.0

DD Method 2.3 8.0 455.7 580.0

RD Method 1.3 3.0 510.4 590.0

(a)350mJ/cm2 (b)700mJ/cm2

Table 2 Development reaction rate constants for exposure doses : (a) 350 mJ/cm2 and (b)700

mJ/cm2

(a)Exposure dose : 350 mJ/cm2

Dipping Development Method (DD Method) (S-1)

Development Temperature (1/T) Exposure dose: 350mJ/cm2

3.4810-3 6.8010-4

3.4310-3 7.3010-4

3.3810-3 6.6010-4

3.3510-3 7.0010-4

3.2810-3 6.7010-4

Vibration Development Method (VD Method) (S-1)

Development Temperature (1/T) Exposure dose: 350mJ/cm2

3.4810-3 8.3010-4

3.4310-3 9.5010-4

3.3810-3 11.5010-4

3.3510-3 13.6010-4

3.3010-3 23.0010-4

Step Puddle Development Method (SP Method) (S-1)

Development Temperature (1/T) Exposure dose: 350mJ/cm2

3.4910-3 5.4010-4

3.4110-3 8.2010-4

3.3810-3 10.2010-4

3.3710-3 12.5010-4

3.3510-3 15.7010-4

10

Reverse Development Method (RD Method) (S-1)

Development Temperature (1/T) Exposure dose: 350mJ/cm2

3.4610-3 1.6410-3

3.4110-3 1.7010-3

3.3810-3 1.7210-3

3.3410-3 1.8510-3

3.3210-3 1.9210-3

(b)Exposure dose : 700 mJ/cm2

Dipping Development Method (DD Method) (S-1)

Development Temperature (1/T) Exposure dose: 700mJ/cm2

3.4810-3 2.2710-3

3.4310-3 3.0110-3

3.3810-3 4.6610-3

3.3510-3 5.4310-3

3.2810-3 5.9810-3

Vibration Development Method (VD Method) (S-1)

Development Temperature (1/T) Exposure dose: 700mJ/cm2

3.4810-3 2.7910-3

3.4310-3 3.5410-3

3.3810-3 4.3810-3

3.3510-3 5.1910-3

3.3010-3 10.7310-3

Step Puddle Development Method (SP Method) (S-1)

Development Temperature (1/T) Exposure dose: 700mJ/cm2

3.4910-3 2.9010-3

3.4110-3 4.3610-3

3.3810-3 7.6010-3

3.3710-3 8.8010-3

3.3510-3 10.0010-3

Reverse Development Method (RD Method) (S-1)

Development Temperature (1/T) Exposure dose: 700mJ/cm2

3.4610-3 3.1110-3

3.4110-3 3.3210-3

3.3810-3 3.5310-3

3.3410-3 3.9410-3

3.3210-3 4.5610-3

11

N2

Table 3 Number of molecular collisions between the N2 deposition layer on the resist surface

and the N2 molecules released from the interior of the resist film.

(molecule / sec)

Development Method Exposure dose: 350 mJ/cm2 700 mJ/cm2

SP Method 4.60106 1.97102

VR Method 3.061020 6.501017

DD Method 3.441025 9.711018

RD Method 8.941027 6.421021

12

(DNQ) Fig. 1 Photochemical reaction scheme involving diazonaphthoquinone (DNQ) novolak-based

positive resist.

+ N2

13

Exposure system: Mask Aligner Q4000 (Quintel Corporation)

Development system: Litho Spin Cup Resist development rate measurement system: RDA

Fig. 2 Configurations of exposure, development, and analysis systems.

14

Resist spin coating

Pre-BakeProximity type 110/minutes

Vacuum desiccators 60minutes

With water 15/30minutes

Exposure (Vacuum contact Exposure)

Development (Dipping, Step puddle, Vibration, Reverse)

Fig. 3 Sample preparation process.

15

(a) Dipping Development Method (DD Method)

(b) Step Puddle Development Method (SP Method)

(c) Vibration Development Method (VD Method)

(d) Reverse Development Method (RD Method)

Fig. 4 Schematic diagrams of the development methods.

Resist

Si Wafer

Developer

Developer Cup

Developer Nozzle

Developer

Spin Chuck

Vibration

Vibration system

Resist

Si Wafer

Si Wafer

16

Line Width (m) Line:Space = 1:1

10 8 6 4 3.5

SP

Method

VD

Method

DD

Method

No resolution

RD

Method

No resolution

Illustration of resist pattern data

SP Method VD Method DD Method RD Method

The resist residues in the space area

Fig. 5 Resist pattern observation results for the defferent development methods.

Resist

residue

17

Development Method Development contrast (tan)

SP (Step Puddle) 3.4

VD (Vibration Development) 2.9

DD (Dipping Development) 2.3

RD (Reverse Development) 1.3

tan

Fig. 6 Comparison of discrimination curves and development contrast (tan) for the different

development methods.

0.01 0.1 1 10 100 1000 100001

10

100

1000

SP Method VD Method DD Method RD Method

Dev

elopm

ent

rate

(nm

/s)

Exposure dose (mJ/cm2)

18

Line:Space = 1:1

Line Width

(m) 10 8 6 5 4

SP Method

VD Method

No resolution

DD Method

No resolution

No resolution

RD Method

No resolution

No resolution

Development

Method

Eop (mJ/cm2 )

Line Width (m) 10 8 6 5 4

Sidewall Angle () 83.3 82.9 82.7 82.1 --------SP Method 439.7

Thickness Loss (%) 12.8 12.7 13.4 25.0 --------

Sidewall Angle () 82.9 82.6 81.4 -------- --------VD Method 466.0

Thickness Loss (%) 13.8 13.8 15.8 -------- --------

Sidewall Angle () 82.2 81.4 ------ -------- --------DD Method 503.2

Thickness Loss (%) 14.6 14.9 ------ -------- --------

Sidewall Angle () 82.3 81.4 ------ -------- --------RD Method 504.8

Thickness Loss (%) 13.6 13.8 ------ -------- --------

Fig. 7 Results of resist pattern simulations for the different development methods.

19

0.00325 0.00330 0.00335 0.00340 0.00345 0.003501E-4

1E-3

0.01

0.1

SP Method VP Method DD Method RD Method

Dev

elopm

ent

const

ant

(s-1)

Development temperature (1/T)

(a) Exposure doses : 350mJ/cm2

0.00325 0.00330 0.00335 0.00340 0.00345 0.003501E-3

0.01

0.1

SP Method VP Method DD Method RD Method

Dev

elopm

ent

const

ant

(s-1)

Development temperature (1/T)

(b) Exposure doses : 700mJ/cm2

(kcal / mol)

Development Method Exposure dose: (a) 350 mJ/cm2 (b) 700 mJ/cm2

SP Method 29.97 35.94

VR Method 11.25 14.87

DD Method 4.41 13.28

RD Method 1.14 9.46

(a) 350mJ/cm2 (b) 700mJ/cm2

Fig. 8 Arrhenius plots and activation energy for exposure doses : (a) 350mJ/cm2 and (b) 700mJ/cm2.

0.001

0.0001

0.001

0.01

0.1

0.01

0.1

20

(a) Model of closed-system development methods

(b) Model of open-system development methods

N2

Fig. 9 A model diagram describing the formation of an N2 deposition layer on the resist surface

during the development.

Exposure Area

Exposure Area

21

0 2 4 6 8 10 12 14

14

16

18

20

22

24

26

28

30

Dev

elopm

ent

rate

(nm

/s)

Concentration of dissolved resist material (mg/ml)

10

Fig.10 Relationship between the concentration of dissolved resist material and the development

rate.