SEQUENTIAL INFILTRATION SYNTHESIS FOR ADVANCED LITHOGRAPHY

• US 20120241411A1
• Filed: 03/22/2012
• Published: 09/27/2012
• Est. Priority Date: 03/24/2011
• Status: Active Grant

• Current Assignee: UChicago Argonne LLC
• Original Assignee: UChicago Argonne LLC
• Inventors: Darling, Seth B., Elam, Jeffrey W., Peng, Qing, Tseng, Yu-Chih
• Granted Patent: US 8,980,418 B2
• Time in Patent Office: Days
• US Class Current: 216/67
• CPC Class Codes: B81C 1/00428 Etch mask forming processes not provided for in groups B81C1/00396 - B81C1/0042
• CPC Class Codes: B81C 2201/0149 Forming nanoscale microstructures using auto-arranging or self-assembling material
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: G03F 7/0041 providing an etching agent upon exposure G03F7/075 takes precedence; photolytic halogen compounds G03F7/0295
• CPC Class Codes: G03F 7/405 Treatment with inorganic or organometallic reagents after imagewise removal
• CPC Class Codes: H01L 21/0273 characterised by the treatment of photoresist layers
• CPC Class Codes: H01L 21/0274 Photolithographic processes
• CPC Class Codes: H01L 21/0277 Electrolithographic processes
• CPC Class Codes: H01L 21/0279 Ionlithographic processes
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/3081 characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 21/3086 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: Y10T 428/31522 Next to metal

Abstract

A plasma etch resist material modified by an inorganic protective component via sequential infiltration synthesis (SIS) and methods of preparing the modified resist material. The modified resist material is characterized by an improved resistance to a plasma etching or related process relative to the unmodified resist material, thereby allowing formation of patterned features into a substrate material, which may be high-aspect ratio features. The SIS process forms the protective component within the bulk resist material through a plurality of alternating exposures to gas phase precursors which infiltrate the resist material. The plasma etch resist material may be initially patterned using photolithography, electron-beam lithography or a block copolymer self-assembly process.

Claims

1. A method of preparing an organic resist mask by sequential infiltration synthesis (SIS) for use in forming at least one patterned feature in a substrate material by an etching or milling process, comprising:

providing a substrate having an organic resist mask layer located over a surface of the substrate, the organic resist mask layer characterized by an etch resistance and including at least one patterned feature adapted to be transferred to the substrate material by the etching or milling process; and

modifying the etch resistance of the organic resist mask layer by exposing the organic resist to a plurality of SIS cycles comprising alternating exposures of a first precursor reactive with the organic resist and a second precursor reactive with the first precursor within the organic resist to form an inorganic protective etch component within the bulk of the organic resist mask layer, thereby increasing the etch resistance of the organic resist mask layer with respect to the etching or milling process.

2. The method of claim 1, wherein the first precursor and the second precursor comprise gas phase precursors.

3. The method of claim 2, wherein the first precursor comprises a metal or metal containing compound, and wherein the inorganic protective etch component comprises a metal oxide or a metal.

4. The method of claim 3, wherein the metal oxide is selected from the group consisting of Al₂O₃, ZnO, SiO₂, HfO₂, ZrO₂ and TiO₂.

5. The method of claim 1, wherein the organic resist mask layer comprises at least one of poly(methyl methacrylate) (PMMA), ZEP520A, poly(methyl glutarimide) (PMGI), phenol formaldehyde resin (DNQ/Novolac), polyhydroxystyrene-based polymers, polyimides and SU-8.

6. The method of claim 1, further comprising forming the at least one patterned feature in the substrate material by performing a plasma etching or ion milling process following modification of the etch resistance of the organic resist mask layer.

7. The method of claim 6, wherein the plasma etching process is defined by a plurality of etching steps performed in order, comprising:

a first etching step configured to break through the protective etch component;

a second etching step configured to break through a layer comprising an oxide of the substrate material; and

a third etching step configured to etch the at least one patterned feature in the substrate.

8. The method of claim 6, wherein the at least one patterned feature is a high-aspect ratio feature.

9. The method of claim 1, wherein the etch resistance is selectively modified by modulating the penetration depth of the protective component within the bulk of the organic resist mask layer.

10. The method of claim 1, wherein the patterned feature of the organic resist mask layer is prepared by photolithography.

11. The method of claim 1, wherein the patterned feature of the organic resist mask layer is prepared by electron beam lithography.

12. A modified organic resist mask layer having an increased resistance to plasma etching or ion milling in response to transferring at least one patterned feature to a substrate material by plasma etching or ion milling, comprising:

an organic resist material disposed over the substrate material and including at least one patterned feature; and

an inorganic protective etch component disposed over at least a portion of the surface of the organic resist material and within at least a portion of the organic resist material to a predetermined infiltration depth within the organic resist material, wherein the plasma etch resistance of the organic resist mask layer is selectively controllable by establishing the infiltration depth of the inorganic protective etch component.

13. The modified organic resist mask layer of claim 12, wherein the organic resist material comprises poly(methyl glutarimide) (PMGI), phenol formaldehyde resin (DNQ/Novolac), polyhydroxystyrene-based polymers, polyimides or SU-8.

14. The modified organic resist mask layer of claim 12, wherein the inorganic protective etch component comprises a metal or a metal oxide.

15. The modified organic resist mask layer of claim 12, wherein the organic resist material comprises a block copolymer comprising at least a first polymer and a second polymer, the block copolymer including a plurality of self-assembled periodic polymer nanostructures, and wherein the inorganic protective etch component is selectively disposed over and within the portion of the organic resist material consisting essentially of the first polymer.

16. The modified organic resist mask layer of claim 15, wherein the block copolymer comprises nanostructured polystyrene-block-poly (methyl methacrylate) (PS-b-PMMA).

17. The modified organic resist mask layer of claim 12 having a thickness below 100 nm.

18. The modified resist mask layer of claim 16, wherein the film thickness is below that leading to deformation under surface tension, commonly referred to as pattern collapse.

19. The modified organic resist mask layer of claim 17, wherein the plasma etch resistance is characterized by an etch resistance that is between about 5 and 10 times the plasma etch resistance of Si.

20. A method of plasma etching a patterned feature in a substrate material without a hard mask using an organic resist mask layer modified by sequential infiltration synthesis (SIS), comprising:

providing a substrate material;

applying the organic resist mask layer over a surface of the substrate material, the organic resist mask layer having a layer thickness and comprising a first organic material;

forming the patterned feature in the organic resist mask layer by lithography;

modifying the plasma etch or ion milling resistance of the organic resist mask layer having the patterned feature by performing a plurality of SIS cycles, comprising;

exposing the organic resist mask layer to a first precursor reactive with the first organic material; and

exposing the organic resist mask layer to a second precursor to form a protective etch component within at least a portion of the first organic material; and

performing a plasma etching or ion milling process that etches the patterned feature in the substrate material to a feature depth,

wherein the modified organic resist mask layer is characterized by a modified plasma etch or ion milling resistance greater than the initial plasma etch or ion milling resistance.

21. The method of claim 20, wherein the first organic material comprises PMMA or ZEP520A and the protective etch component comprises a metal oxide.

22. The method of claim 21, wherein the substrate material comprises Si.

23. The method of claim 21, wherein the modified plasma etch resistance is selectively controllable by performing a predetermined number of SIS cycles.

24. The method of claim 20, wherein the patterned feature on the organic resist mask layer is prepared by photolithography.

25. The method of claim 20, wherein the patterned feature of the organic resist mask layer is prepared by electron beam lithography.

26. The method of claim 24, wherein the feature depth is between about 5 and 10 times the layer thickness.

27. The method of claim 20, wherein the organic resist mask layer comprises a block copolymer, and wherein the first precursor is substantially non-reactive with at least one block of the block copolymer.

28. The method of claim 27, wherein the block copolymer comprises nanostructured polystyrene-block-poly (methyl methacrylate) (PS-b-PMMA).

29. The method of claim 20, wherein the plasma etching process is defined by a plurality of etching steps performed in order, comprising:

a first etching step configured to break through the protective etch component;

a second etching step configured to break through a layer comprising an oxide of the substrate material; and

a third etching step configured to etch the patterned feature in the substrate material to the feature depth

30. The method of claim 29, further comprising removing a remaining portion of the organic resist mask layer from the surface of the substrate material.