SPIN-ON SPACER MATERIALS FOR DOUBLE- AND TRIPLE-PATTERNING LITHOGRAPHY

• US 20100170868A1
• Filed: 01/05/2010
• Published: 07/08/2010
• Est. Priority Date: 01/07/2009
• Status: Active Grant

• Current Assignee: Brewer Science Inc.
• Original Assignee: Brewer Science Inc.
• Inventors: Smith, Brian, Lin, Qin, Claypool, James, Guerrero, Douglas J., Puligadda, Rama
• Granted Patent: US 9,640,396 B2
• Time in Patent Office: Days
• US Class Current: 216/13
• CPC Class Codes: C08G 77/20 containing silicon bound to unsaturated aliphatic groups C08G77/045 takes precedence
• CPC Class Codes: G03F 7/40 Treatment after imagewise removal, e.g. baking
• CPC Class Codes: H01L 21/02208 the precursor containing a compound comprising Si
• CPC Class Codes: H01L 21/0337 characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
• CPC Class Codes: H01L 21/0338 Process specially adapted to improve the resolution of the mask
• CPC Class Codes: H01L 21/3121 Layers comprising organo-silicon compounds

Abstract

Novel double- and triple-patterning methods are provided. The methods involve applying a shrinkable composition to a patterned template structure (e.g., a structure having lines) and heating the composition. The shrinkable composition is selected to possess properties that will cause it to shrink during heating, thus forming a conformal layer over the patterned template structure. The layer is then etched to leave behind pre-spacer structures, which comprise the features from the pattern with remnants of the shrinkable composition adjacent the feature sidewalls. The features are removed, leaving behind a doubled pattern. In an alternative embodiment, an extra etch step can be carried out prior to formation of the features on the template structure, thus allowing the pattern to be tripled rather than doubled.

Claims

1. A method of forming a microelectronic structure, said method comprising:

providing a precursor structure having a patterned surface, said patterned surface including at least one raised feature having first and second sidewalls and an upper surface;

applying a shrinkable composition to said patterned surface, said composition covering said feature sidewalls and upper surface;

heating said shrinkable composition so as to form a conformal layer of said composition on said patterned surface and over said feature; and

removing at least some of said conformal layer to yield a pre-spacer structure comprising said feature and remnants of said conformal layer against said feature sidewalls.

2. The method of claim 1, wherein said shrinkable composition has an initial thickness after said applying and before said heating, and said conformal layer has a final thickness after said heating and before said removing, said final thickness being at least about 25% less than said initial thickness.

3. The method of claim 1, further comprising removing said raised feature from said pre-spacer structure so as to leave said remnants on said patterned surface.

4. The method of claim 3, wherein said patterned surface has a first pattern prior to said applying and a second pattern after removing said raised feature, said second pattern being double that of the first pattern.

5. The method of claim 3, there being one or more layers below said patterned surface and further comprising transferring the pattern created by said remnants down to one or more of said layers below said patterned surface.

6. The method of claim 1, said patterned surface including at least two of said raised features immediately adjacent one another, wherein after said heating there is a maximum thickness A of said conformal layer on the upper surface of each feature and a minimum thickness B on said patterned surface at a point between said two raised features, and B is less than or equal to A.

7. The method of claim 1, wherein said precursor structure comprises:

a first layer having an upper surface;

a second layer having an upper surface, said second layer being adjacent said first layer upper surface; and

said patterned surface being adjacent said second layer upper surface.

8. The method of claim 7, said first layer comprising a spin-on carbon layer, said second layer comprising a hard mask layer, and said patterned surface comprising a photosensitive layer.

9. The method of claim 1, said patterned surface having a plurality of said raised features at a pitch of from about 1:

2 to about 1;

4.

10. The method of claim 1, wherein said patterned structure further comprises a second raised feature that is below said at least one raised feature, said second raised feature having first and second sidewalls and an upper surface and said at least one raised feature being in contact with said second raised feature sidewalls and upper surface, said second raised feature and said at least one raised feature being formed of different materials.

11. The method of claim 10, further comprising removing said at least one raised feature from said pre-spacer structure so as to leave said remnants and said second raised feature on said patterned surface.

12. The method of claim 11, wherein said patterned surface has a first pattern prior to said applying and a second pattern after removing said at least one raised feature, said second pattern being triple that of the first pattern.

13. The method of claim 1, wherein said shrinkable composition is selected from the group consisting of:

(a) a composition comprising a crosslinking agent dispersed or dissolved in a solvent system;

(b) a composition comprising a polymer dispersed or dissolved in a solvent system, said polymer comprising acid-labile side chains;

(c) a composition comprising an etch-resistant polymer dispersed or dissolved in a solvent system comprising a heavy solvent; and

(d) a composition comprising an organometallic compound dissolved or dispersed in a solvent system.

14. The method of claim 13, wherein said shrinkable composition is (a), and said crosslinking agent is selected from the group consisting of poly(melamine-co-formaldehyde) methylated, poly(melamine-co-formaldehyde) butylate, poly(melamine-co-formaldehyde) isobutylate, hexamethylmelamine, glycolurils, 1,3-bis(methoxymethyl)-4,5-bis(methoxy)-ethylenurea, 1,3-bis(methoxymethyl)urea, and the following derivatives:

15. The method of claim 13, wherein said shrinkable composition is (b), and said polymer comprises monomers selected from the group consisting of styrenes, methyl acrylates, and acrylates, and said acid-labile side chain is selected from the group consisting of t-butyl, acetyls, adamantyls, and lactones.

16. The method of claim 13, wherein:

said shrinkable composition is (c);

said polymer has an etch selectivity compared to that of said at least one raised feature of less than about 0.30 when O₂ is used as the etchant; and

said heavy solvent is selected from the group consisting of 2-ethyl-2-adamantyl acrylate, 2-methyl-2-adamantyl methacrylate, 2-methyl-adamantyl acrylate, 1-dodecene, and mixtures thereof.

17. The method of claim 13, wherein said shrinkable composition is (d), and said organometallic compound is selected from the group consisting of titanium (IV) bis(ethyl acetoacetato) diisopropoxide, titanium (IV) bis(ammonium lactato) dihydroxide, titanium (IV) diisopropoxide (bis-2,3-pentanedionate), aluminum diisopropoxide ethylacetoacetate, vanadium (IV) oxide bis(2,4-pentane-dionate), zirconium dibutoxide bis(2,4-pentane-dionate), aluminum pentanedionate bis(ethylacetoacetate), hafnium dibutoxide bis(2,4-pentanedionate), vanadium III 2,4-pentanedionate, and poly(dibutyl titanate).

18. The method of claim 1, wherein said heating comprises heating at a temperature of less than about 300°

C.

19. The method of claim 18, wherein said heating comprises heating at a temperature of less than about 120°

C.

20. The method of claim 19, wherein said patterned surface comprises a photosensitive layer, and said shrinkable composition comprises a solvent selected from the group consisting of mesitylene, methyl isobutyl carbinol, d-limonene, and mixtures thereof.