Tone inverted directed self-assembly (DSA) fin patterning

1. A method for directed self-assembly (DSA) fin patterning, the method comprising:

forming a block copolymer layer over a lithographic stack, the block copolymer layer having a first block and a second block, the lithographic stack disposed over a hard mask and a substrate, and the hard mask comprising a first dielectric layer and a second dielectric layer;

removing the first block from the block copolymer to define a fin pattern in the block copolymer layer with the second block;

etching the fin pattern into the first dielectric layer of the hard mask;

filling the fin pattern within the first dielectric layer of the hard mask with a tone inversion material;

etching back the tone inversion material that overfills the fin pattern and remains on top of the first dielectric layer;

removing the first dielectric layer selectively to define an inverted fin pattern from the tone inversion material;

etching the inverted fin pattern into the second dielectric layer of the hard mask;

removing the tone inversion material; and

transferring the inverted fin pattern of the second dielectric layer into the substrate to define fins.

2. The method of claim 1 , wherein the tone inversion material is a spin-on metal oxide.

3. The method of claim 2 , wherein spin-on metal oxide comprises titanium (Ti), ruthenium (Ru), tungsten (W), hafnium (Hf), or any combination thereof.

4. The method of claim 1 , wherein the block copolymer comprises polystyrene (PS) and poly(methyl methacrylate) (PMMA).

5. The method of claim 1 , further comprising a chemical guiding pattern over the lithographic stack.

6. The method of claim 5 , wherein the chemical guiding pattern has a surface topography.

7. The method of claim 1 , wherein the first dielectric layer is silicon oxide or silicon nitride.

8. A method for DSA fin patterning, the method comprising:

forming a block copolymer layer over a neutral layer, the block copolymer layer having a first block and a second block, the neutral layer disposed over a lithographic stack, the lithographic stack disposed over a hard mask and a substrate, and the hard mask comprising a first dielectric layer and a second dielectric layer;

removing the first block from the block copolymer and a corresponding portion of the neutral layer beneath the first block to define a fin pattern in the block copolymer layer with the second block;

etching the fin pattern into the first dielectric layer of the hard mask;

filling the fin pattern within the first dielectric layer of the hard mask with a tone inversion material;

etching back the tone inversion material that overfills the fin pattern and remains on top of the first dielectric layer;

removing the first dielectric layer selectively to define an inverted fin pattern from the tone inversion material;

etching the inverted fin pattern into the second dielectric layer of the hard mask;

removing the tone inversion material; and

transferring the inverted fin pattern of the second dielectric layer into the substrate to define fins.

9. The method of claim 8 , wherein the substrate is a silicon substrate.

10. The method of claim 8 , wherein the tone inversion material is a spin-on material.

11. The method of claim 8 , wherein the tone inversion material has etch selectivity over dielectric materials of the hard mask.

12. The method of claim 8 , wherein the etching in the first dielectric layer or second dielectric layer is wet etching.

13. The method of claim 8 , wherein the etching in the first dielectric layer or the second dielectric layer is plasma etching.

14. The method of claim 8 , wherein the lithographic stack comprises an organic planarization (OPL) layer and an anti-reflective coating.

15. A method for DSA fin patterning, the method comprising:

forming a block copolymer layer over a lithographic stack, the block copolymer having a first block and a second block, the lithographic stack disposed over a hard mask and a substrate, and the hard mask comprising a first dielectric layer and a second dielectric layer;

removing the first block from the block copolymer to define a fin pattern in the block copolymer layer with the second block;

etching the fin pattern into the first dielectric layer of the hard mask;

filling the fin pattern within the first dielectric layer of the hard mask with a tone inversion material;

etching back the tone inversion material that overfills the fin pattern and remains on top of the first dielectric layer;

removing the first dielectric layer selectively to define an inverted fin pattern from the tone inversion material;

etching the inverted fin pattern into the second dielectric layer of the hard mask;

removing the tone inversion material;

transferring the inverted fin pattern of the second dielectric layer into the substrate to define fins; and

etching the fins into the substrate after removing the tone inversion material.

16. The method of claim 15 , wherein tone inversion material is a silicon-containing polymer.

17. The method of claim 15 , wherein the tone inversion material is siloxane, silsesquioxane, hydrogen silsesquioxane, or any combination thereof.

18. The method of claim 15 , further comprising a chemical guiding pattern over the lithographic stack.

19. The method of claim 18 , wherein the chemical guiding pattern is substantially free of a surface topography.

20. The method of claim 15 , wherein the tone inversion material is etch selective to the hard mask.