UV Curable Silsesquioxane Resins For Nanoprint Lithography

• US 20090256287A1
• Filed: 04/09/2009
• Published: 10/15/2009
• Est. Priority Date: 04/09/2008
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Fu, Peng-Fei, Guo, Lingjie Jay
• Granted Patent: US 8,293,354 B2
• Time in Patent Office: Days
• US Class Current: 264/447
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C08G 77/04 Polysiloxanes
• CPC Class Codes: C08G 77/14 containing silicon bound to oxygen-containing groups C08G77/045 takes precedence
• CPC Class Codes: C08G 77/24 halogen-containing groups
• CPC Class Codes: C09D 183/08 containing silicon bound to organic groups containing atoms other than carbon, hydrogen, and oxygen
• CPC Class Codes: G03F 7/0002 Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
• CPC Class Codes: G03F 7/038 Macromolecular compounds which are rendered insoluble or differentially wettable G03F7/075 takes precedence; macromolecular azides G03F7/012; macromolecular diazonium compounds G03F7/021
• CPC Class Codes: G03F 7/0757 Macromolecular compounds containing Si-O, Si-C or Si-N bonds G03F7/0752 takes precedence
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/24479 including variation in thickness
• CPC Class Codes: Y10T 428/2457 Parallel ribs and/or grooves
• CPC Class Codes: Y10T 428/24612 Composite web or sheet
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/269 including synthetic resin or polymer layer or component
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

Radiation-curable silsesquioxane resin materials are employed for micro- and nanolithography. The resin materials can include a radiation-curable silsesquioxane resin and a photo-initiator having low viscosity. The low viscosity of the liquid system allows imprinting with low pressure and low temperature; e.g. room temperature. The resist'"'"'s dry etching resistance is increased and the cured film is more easily separated from the mask. Due to its high modulus after cure, the material allows the fabrication of micro- and nano-features having high aspect ratios while providing a high throughput. Various pattern sizes, for example, ranging from tens of microns to as small as a few nanometers, may be achieved with the UV-curable material system.

Claims

1. A composition comprising a silsesquioxane resin, wherein the silsesquioxane resin comprises at least one radiation-curable group.

2. The composition of claim 1, wherein the radiation-curable group is curable with thermal radiation, actinic radiation, or both thermal and actinic radiation.

3. The composition of claim 1, further comprising a member selected from the group consisting of photoacid generator, solvent, and combinations thereof.

4. The composition of claim 3, wherein the amount of solvent provides the composition with a viscosity of about 1 Pa·

s to about 300 Pa·

s at about 25°

C.

5. The composition of claim 1, wherein the cured composition has a Young'"'"'s modulus of about 0.5 GPa to about 4.5 GPa.

6. The composition of claim 1, wherein the silsequioxane resin comprises at least one unit selected from each of formulas (I) and (II):

—

(R¹SiO_x)—

 

 

(I)

—

(R²SiO_x)—

 

 

(II)

wherein;

R¹ is independently selected from the group consisting of hydrogen;

C1-C12 linear or branched alkyl groups;

C1-C12 linear or branched alkyl groups including at least one heteroatom selected from the group consisting of nitrogen, oxygen, halogen, and combinations thereof;

C1-C12 linear or branched carboxylate groups;

C1-C12 linear or branched ether groups;

C6-C12 aryl groups, including phenyl groups; and

fluoro-containing organic groups, including fluoro-alkyl groups and fluoro-ether groups;

R² is a radiation-curable group independently selected from the group consisting of acrylate, epoxy, and vinyl ether groups; and

x is about 1 to about 1.5.

7. The composition of claim 1, wherein the silsequioxane resin comprises at least one di-functional (D) unit of formula (III) derived from a difunctional silane, R³R⁴SiX₂, wherein X is a halide, alkoxyl, or acetoxy group:

—

(R³R⁴SiO)—

 

 

(III)

wherein;

R³ and R⁴ are independently selected from the group consisting of hydrogen;

C1-C12 linear or branched alkyl groups;

C1-C12 linear or branched alkyl groups including at least one heteroatom selected from the group consisting of nitrogen, oxygen, halogen, and combinations thereof;

C1-C12 linear or branched carboxylate groups;

C1-C12 linear or branched ether groups;

C6-C12 aryl groups, including phenyl groups; and

fluoro-containing organic groups, including fluoro-alkyl groups and fluoro-ether groups; and

a radiation-curable group selected from the group consisting of acrylate, epoxy, and vinyl ether groups.

8. The composition of claim 1, wherein the silsequioxane resin comprises at least one quadri-functional (Q) unit of formula (IV) derived from SiX₄ monomer, wherein X is a halide, alkoxyl, or acetoxy group:

(IV) —

(SiO₂)—

.

9. The composition of claim 1, wherein the silsesquioxane resin comprises at least one unit selected from the group consisting of formulas (V) and (VI):

—

(R¹SiO_x)—

(R²SiO_x)—

 

 

(V)

—

(R¹SiO_x)—

(R²SiO_x)—

(R³SiO_x)—

 

 

(VI)

wherein;

R¹ is independently selected from the group consisting of hydrogen;

C1-C12 linear or branched alkyl groups;

C1-C12 linear or branched alkyl groups including at least one heteroatom selected from the group consisting of nitrogen, oxygen, halogen, and combinations thereof;

carboxylate groups and ether groups;

C6-C12 aryl groups, including phenyl groups; and

fluoro-containing organic groups, including fluoro-alkyl groups and fluoro-ether groups;

R² is a radiation-curable group independently selected from the group consisting of acrylate, epoxy, and vinyl ether groups;

R³ is independently selected from the group consisting of C1-C12 linear or branched alkyl groups including at least one fluorine; and

x is about 1 to about 1.5.

10. The composition of claim 1, wherein the silsesquioxane resin comprises one of the following formulas:

[R¹SiO_3/2]_m[R²SiO_3/2]_n (T^R1T^R2, m+n=1)

[R SiO_3/2]_m[R²SiO_3/2]_n[R³R⁴SiO]_p (T^R1T^R2D^R3,R4, m+n+p=1),

[R¹SiO_3/2]_m[R²SiO_3/2]_n[R³R⁴SiO]_p[SiO₂]_q (T^R1T^R2D^R3,R4Q, m+n+p+q=1);

[R¹SiO_3/2]_m[R²SiO_3/2]_n[SiO₂]_q (T^R1T^R2Q, m+n+q=1);

[R¹SiO_3/2]_m[R²SiO_3/2]_n[R⁵SiO_3/2]_o (T^R1T^R2T^R5, m+n+o=1);

wherein;

R¹, R³, and R⁴ are independently selected from the group consisting of hydrogen;

C1-C12 linear or branched alkyl groups;

C1-C12 linear or branched alkyl groups including at least one heteroatom selected from the group consisting of nitrogen, oxygen, halogen, and combinations thereof;

C1-C12 linear or branched carboxylate groups;

C1-C12 linear or branched ether groups;

C6-C12 aryl groups, including phenyl groups; and

fluoro-containing organic groups, including fluoro-alkyl groups and fluoro-ether groups;

R² is a radiation-curable group independently selected from the group consisting of acrylate, epoxy, and vinyl ether groups;

R⁵ is a fluoro-containing organic group, including fluoro-alkyl groups and fluoro-ether groups;

m is the molar ratio of [R¹SiO_3/2] unit;

n is the molar ratio of [R²SiO_3/2] unit;

p is the molar ratio of [R³R⁴SiO] unit;

q is the molar ratio of [SiO₂] unit; and

o is the molar ratio of [R⁵SiO] unit;

with the proviso that the sum of the molar ratios of all components in each formula is equal to 1.

11. A mold for nanoimprinting lithography comprising a cured silsesquioxane resin on a substrate, the cured silsesquioxane resin comprising a feature having at least one dimension of about 2 nanometers to about 100 micrometers.

12. The mold of claim 11, wherein the silsesquioxane resin comprises one of the following formulas:

[R¹SiO_3/2]_m[R²SiO_3/2]_n (T^R1T^R2, m+n=1)

[R¹SiO_3/2]_m[R²SiO_3/2]_n[R³R⁴SiO]_p (T^R1T^R2D^R3,R4, m+n+p=1),

[R¹SiO_3/2]_m[R²SiO_3/2]_n[R³R⁴SiO]_p[SiO₂]_q (T^R1T^R2D^R3,R4Q, m+n+p+q=1);

[R¹SiO_3/2]_m[R²SiO_3/2]_n[SiO₂]_q (T^R1T^R2Q, m+n+q=1);

[R¹SiO_3/2]_m[R²SiO_3/2]_n[R⁵SiO_3/2]_o (T^R1T^R2T^R5, m+n+o=1);

wherein;

R¹, R³, and R⁴ are independently selected from the group consisting of hydrogen;

C1-C12 linear or branched alkyl groups;

C1-C12 linear or branched alkyl groups including at least one heteroatom selected from the group consisting of nitrogen, oxygen, halogen, and combinations thereof;

C1-C12 linear or branched carboxylate groups;

C1-C12 linear or branched ether groups;

C6-C12 aryl groups, including phenyl groups; and

fluoro-containing organic groups, including fluoro-alkyl groups and fluoro-ether groups;

R² is a radiation-curable group independently selected from the group consisting of acrylate, epoxy, and vinyl ether groups;

R⁵ is a fluoro-containing organic group, including fluoro-alkyl groups and fluoro-ether groups;

m is the molar ratio of [R¹SiO_3/2] unit;

n is the molar ratio of [R²SiO_3/2] unit;

p is the molar ratio of [R³R⁴SiO] unit;

q is the molar ratio of [SiO₂] unit; and

o is the molar ratio of [R⁵SiO] unit;

with the proviso that the sum of molar ratios of all components in each formula is equal to 1.

13. The mold of claim 11, wherein the cured silsesquioxane resin comprises a fluoro-containing organic group, fluoro-alkyl group, or fluoro-ether group.

14. The mold of claim 11, wherein the substrate is flexible.

15. The mold of claim 11, wherein the cured silsesquioxane resin has a modulus of about 0.5 GPa to about 4.5 GPa.

16. A method of nanoimprint lithography comprising:

applying a liquid resist composition to a substrate, the composition comprising a silsesquioxane resin, wherein the silsesquioxane resin comprises at least one radiation-curable group;

imprinting the resist with a mold and curing the resist; and

separating the mold and the cured resist.

17. The method of claim 16, wherein the applying includes spin coating.

18. The method of claim 16, wherein the imprinting is performed at about 25°

C. using a pressure of about 50 psi or less.

19. The method of claim 16, wherein curing the resist includes exposing the resist to thermal radiation, actinic radiation, or both thermal and actinic radiation.

20. The method of claim 16, wherein the mold includes features having dimensions from about 2 nanometers to about 100 micrometers.

21. The method of claim 16 wherein the substrate is flexible.

22. The method of claim 16, wherein the substrate includes a coating that is soluble in a solvent and the liquid resist composition is applied onto the coating.

23. The method of claim 22, further comprising:

removing residual resist to expose a portion of the underlying coating after imprinting and curing;

etching the exposed portion of the underlying coating, thereby exposing a portion of the substrate, and undercutting a portion of the resist;

depositing a material onto the exposed portion of the substrate; and

lifting-off the remaining resist and coating by solubilizing the coating with solvent, leaving the substrate and deposited material.

24. The method of claim 23, wherein removing residual resist includes removing residual resist by reactive ion etching.

25. The method of claim 23, wherein etching the exposed portion of the underlying coating and undercutting a portion of the resist includes reactive ion etching.

26. The method of claim 23, wherein the deposited material is a metal.