RAFT Technology for the Production of Advanced Photoresist ... · RAFT Technology for the Production of Advanced Photoresist Polymers ... Rizzardo, E., Thang, ... RAFT Technology

RAFT Technology for the Production of Advanced Photoresist Polymers

Michael T. Sheehanb, William B. Farnhama, Hiroshi Okazakib, James R. Sounikc, George W. ClarkcaE. I. DuPont de Nemours, Central Research and Development, Wilmington, DE 19880, bDuPont Electronic Polymers L.P., Ingleside, Texas 78359, cDuPont Electronic Polymers L.P., Dayton, Ohio, 45418

2

Copyright © 2008 DuPont. All rights reserved.

Design Concept

Produce fully compatible topcoat-less 193 immersion photoresist polymers using Reversible Addition Fragmentation Chain Transfer (RAFT) technology to control polymer architecture and provide top surface hydrophobicity

- Produce a random copolymer of matching commercial 193 nm resistpolymer using RAFT technology

- Attach a hydrophobic block to the active end of the random resist polymer

- Remove the end group

- Solution blend with standard 193 nm photoresists

3


RAFT Reagent Synthesis

2 C12H25SH + 2 KOt-Bu + 2 CS2 + I2 C12H25SC(S)SSC(S)SC12H25

Step 2 - 4-cyano-4-(dodecylsulfanylthiocarbonyl)sulfanyl pentanoic acid

Step 1 - bis-(dodecylsulfanylthiocarbonyl) disulfide

C12H25SC(S)SSC(S)SC12H25 + 4,4’-azobis(4-cyanopentanoic acid)

2 C12H25SC(S)SC(CH3)(CN)CH2CH2CO2H

Step 3 - methyl 4-cyano-4-(dodecylsulfanylthiocarbonyl)sulfanylpentanoate

C12H25SC(S)SC(CH3)(CN)CH2CH2CO2H + DBU + CH3I

C12H25SC(S)SC(CH3)(CN)CH2CH2CO2CH3

4


Synthesis of Poly(α-GBLMA/MAdMA/ECPMA)

O

O

MAdMA

O

O O

O

a-GBLMA

OO

ECPMA

+ +RAFT

V601

R=RAFT end group =S SC12H25

S

RAFT = 4-cyano-4 -(dodecylsulfanylthiocarbonyl)sulfanyl pentanoate

O

O

O

O

O

O

*

R

OO

z

Random terpolymerMw = 3330, PD = 1.15

x yn

5


Synthesis of Poly(α-GBLMA/MAdMA/ECPMA-b-1H,1H,2H,2H-perfluorooctyl methacrylate)

F-Block 1

O

O

O

O

O

O

*

R

OO

z

Random terpolymerMw = 3330, PD = 1.15

x yn


S

RAFT = 4-cyano-4 -(dodecylsulfanylthiocarbonyl)sulfanyl pentanoate

+

FF

FF F

F

FF

FF

F FF

O O

C6-Z

Mw = 4981; Mn = 4251; PD = 1.17Block coplymer

OO

FF

F FFF

F F

F F

FFF

R

b

O

OO

O

O

O

*

OO

zx yn

6


Reduction of trithiocarbonate end group from Poly(α-GBLMA/MAdMA/ECPMA)-b-(1H,1H,2H,2H-perfluorooctyl methacrylate)

F-Block 1 with RAFT end group F-Block 1 with RAFT end group removed


S

R3NH H2PO2

radical initiator

OO

FF

F FFF

F F

F F

FFF

H

b

O

OO

O

O

O

*

OO

zx yn

Mw = 4981; Mn = 4251; PD = 1.17Block coplymer

OO

FF

F FFF

F F

F F

FFF

R

b

O

OO

O

O

O

*

OO

zx yn

7


Preparation of blends of 193 nm resist copolymer with fluorinated block copolymer additive

Blends of F-Block 1 with commercial random Poly(α-GBLMA/MAdMA/ECPMA) with Mw of ~ 8,000 Mw and PD of 1.2 were produced in the following ratios (1:2, 1:4, 1:9, 1:29, 1:100, 1:199) in PGMEA/EL (2:1) as 12 wt. % solutions and spun on Si wafers. Film were annealed during post apply bake to allow alignment of the F-Block portion of the polymer at or near the surface of the resist. Contact angles are shown below.

Weight Fraction Block Copolymer (F-Block 1)

Cont

act

Ang

le (

degr

ees)

1.00.80.60.40.20.0

120

110

100

90

80

70

60

50

Variableadvancingreceding

118120120120119

109

102

80 80828384

87

73

81

54

Advancing and Receding Water Contact Angles - (F-Block 1) in 193 terpolymer

8


Conceptual drawing of F-Block 1 alignment in resist

wafer surface

photoresist surface/water interface

OO

OO

OO

*

*

O

O

xy

zn

OO

OO

OO

*

*

O

O

xy

zn

OO

OO

OO

*

*

O

O

xy

zn

OO

OO

OO

*

*

O

O

xy

zn

OO

OO

OO

*

*

O

O

xy

zn

OO F

FFFFFF

FF

F FFF

H b

OO

OO

OO

*

O

O

zx

yn

OO F

FFFFFF

FF

F FFF

H b

OO

OO

OO

*

O

O

zx

yn

hydrophobic surface

9


1 wt.% (F-block 2) in a commercial 193 nm resist

31 mJ/cm2 32 mJ/cm2 33 mJ/cm2 34 mJ/cm2 35 mJ/cm2 36 mJ/cm2 37 mJ/cm2 38 mJ/cm2 39 mJ/cm2 40 mJ/cm2

-0.5 μm -0.4 μm -0.3 μm -0.2 μm -0.1 μm 0.0 μm 0.1 μm 0.2 μm 0.3 μm 0.4 μm

Mask CD 100 Mask CD 110 Mask CD 120 Mask CD 130 Mask CD 140 Mask CD 150

137.0 122.4 122.7 123.9 126.7 131.9

120 nm L/S @ best focus

120 nm L/S @ 34.0 mJ/cm2

Linearity @ 34.0 mJ/cm2

10




-0.5 μm -0.4 μm -0.3 μm -0.2 μm -0.1 μm 0.0 μm 0.1 μm 0.2 μm 0.3 μm 0.4 μm 0.5 μm


120 nm L/S @ 32.0 mJ/cm2



139.2 125.8 124.8 125.1 127.2 133.7

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-0.4 μm -0.3 μm -0.2 μm -0.1 μm 0.0 μm 0.1 μm 0.2μm 0.3 μm 0.4 μm



120 nm L/S @ 31.0 mJ/cm2


137.6 135.1 118.1 118.0 120.9 129.9

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Results and discussions

Customized F-containing block copolymer can be synthesized via RAFT technology to allow for full compatibility with commercial 193 nm polymers resulting in a topcoat-less 193 immersion photoresist

The F-block copolymer migrates to the air-solid interface and provides a hydrophobic surface. The A-block of each polymer chain provides compatibility with the main resist polymer and enables development of exposed area

Further optimization will involve refined selection of the fluoromonomer and size of the fluoropolymer block to achieve thedesired advancing and receding contact angles

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Acknowledgements and References

ACKNOWLEDGEMENTSThe authors would like to acknowledge the contributions of CSIRO in the development of RAFT technology. We would also like to acknowledge JSR Micro for the microlithography and SEMs.

REFERENCES[1] Wei, Y. et al., "Selection and evaluation of developer-soluble topcoat for 193-nm immersion lithography," Proc. SPIE 6153, 6153-71, (2006)[2] Lee, T.Y., et al., "Polymers with well-controlled molecular weight for DUV/VUV lithography," Proc. SPIE 5039, 548-557(2003)[3] Kim, Sang Soo et al, "Modified polymer architecture for immersion lithography," Proc. SPIE 6519, 65191W-1, (2007)[4] Moad, G., Rizzardo, E., Thang, S. H., "Living radical polymerization by RAFT process," Australian Journal of Chemistry 58(6), 379-410 (2005)[5] Black, C.T., et al, "Polymer self assembly in semiconductor microelectronics," IBM J. Res. & Dev. 51, No. 5., (605-632), (2007) [6] Chiefari, J., Chong, Y.K., Ercole, F., Krstina, J., Jeffery, J., Le, T., Mayadunne Roshan,T.A., Meijs, G.F., Moad, C. L., Moad, G., Rizzardo, E., Thang,

S.H., "Living free-radical polymerization by reversible addition-fragmentation chain transfer: the RAFT process," Macromolecules 31(16), 5559-5562 (1998)

[7] Mayadunne, R.T.A., E. Rizzardo, J. Chiefari, J. Krstina, G. Moad, A. Postma, S. H. Thang, "Living polymers by the use of trithiocarbonates as reversible addition-fragmentation chain transfer (RAFT) agents. ABA triblock copolymers by radical polymerization in two steps," Macromolecules 33(2), 243-245 (2000)

[8] Moad, G., Chefari, J., Chong, Y.K., Krstina, J., Mayadunne, R.T.A, Postma, A., Rizzardo, E., Thang, S.H., "Living free radical polymerization with reversible addition-fragmentation chain transfer (the life of RAFT)," Polymer International 49(9), 993-1001 (2000)

[9] Chong, Y.K., Le, T.P.T., Moad, G., Rizzardo, E., Thang, S.H.,"A more versatile route to block copolymers and other polymer of complex architecture by living radical polymerization: the RAFT process," Macromolecules 32(6), 2071-2074 (1999)

[10] Mayadunne, R.T.A., Rizzardo, E., Chiefari, J., Chong, Y.K., Moad, G., Thang, S.H., " Living radical polymerization with reversible addition-fragmentation chain transfer (RAFT polymerization) using dithiocarbamates as chain transfer agents," Macromolecules 32(21), 6977-6980 (1999)

[11] Moad, G., Chong, Y., Postma, A., Rizzardo, E., Thang, S., "Advances in RAFT polymerization: the synthesis of polymers with defined end-groups," Polymer 46, 8458-8468 (2005)

[12] Chong, Y., Moad, G., Rizzardo, E., Thang S., "Thiocarbonylthio end group removal from RAFT-synthesized polymers by radical-induced reduction," Macromolecules 40, 4446-4455 (2007)

[13] Farnham, W. B., Fryd, M., Moad, G., Thang, S.H., Rizzardo, E., “Removing sulfur-containing end groups from vinyl polymer without changing solvent,” PCT Int. Appl. WO 2005113612, (2005)

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RAFT Technology for the Production of Advanced Photoresist ... · RAFT Technology for the Production of Advanced Photoresist Polymers ... Rizzardo, E., Thang, ... RAFT Technology