Sequential infiltration synthesis for enhancing multiple-patterning lithography
Simplified methods of multiple-patterning photolithography using sequential infiltration synthesis to modify the photoresist such that it withstands plasma etching better than unmodified resist and replaces one or more hard masks and/or a freezing step in MPL processes including litho-etch-litho-etch photolithography or litho-freeze-litho-etch photolithography.
1. A method of preparing inorganic features for forming multiple-patterned nanostructures, comprising:
applying a first resist layer to a substrate stack having a substrate and a first hard mask disposed thereon;
patterning the first resist layer with a first pattern;
modifying the patterned first resist layer with a first iteration of inorganic features infiltrated within the patterned first resist layer using Sequential Infiltration Synthesis (SIS) treatment;
applying a second resist layer to the substrate stack;
patterning the second resist layer with a second pattern;
modifying the patterned second resist layer with a second iteration of inorganic features infiltrated within the pattered second resist layer using Sequential Infiltration Synthesis (SIS) treatment; and
engraving a multiple-density pattern reflecting the first pattern and the second pattern onto the substrate.
2. The method of claim 1 , further comprising the step of modifying at least one further patterned resist layer with at least one further iteration of inorganic features providing at least one further pattern for the substrate.
3. The method of claim 1 , wherein no hard mask is deposited between the substrate and the second iteration of inorganic features.
4. The method of claim 1 , wherein the first resist layer and second resist layer comprise a polyacrylate material.
5. The method of claim 1 , wherein the first iteration of inorganic features are formed in the first resist layer and the second iteration of inorganic features are formed in the second resist layer, wherein the material of the first resist layer and the material of the second resist layer is selected from the group consisting of poly(methyl methacrylate) (PMMA), poly9methyl glytarimide) (PMGI), phenol formaldehyde resin (DNQ/Novolac), polyhydoxystyrene-based polymers, and polyimides.
6. The method of claim 1 , wherein the multiple-density pattern is a double-density pattern.
7. The method of claim 1 , wherein the SIS treatment comprises alternating exposures of a first precursor reactive with the first resist layer and a second precursor reactive with the first precursor within the first resist layer to form an inorganic protective etch component within the bulk of the first resist layer.
8. The method of claim 7 , wherein the first precursor and the second precursor comprise gas phase precursors.
9. The method of claim 7 , 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.
10. The method of claim 9 , wherein the metal oxide is selected from the group consisting of Al2O3, ZnO, SiO2, HfO2, ZrO2, Nb2O5 and TiO2.
11. A method of lithography comprising:
applying a first resist layer on a substrate stack,
patterning the first resist layer to form a first pattern;
developing the patterned first resist layer;
infiltrating the developed first resist layer using Sequential Infiltration Synthesis wherein:
a first precursor is exposed to and infiltrates into the developed first resist layer and reactions with the bulk of the developed first resist layer; and
a second precursor is exposed to and infiltrates into the developed first resist layer and reactions with the first precursor to form an inorganic component within the developed first resist layer;
etching the substrate stack to engrave the first pattern and the second pattern into a substrate; and
removing the developed first resist layer.
12. The method of claim 11 , further comprising the steps of applying further resist layers to the substrate stack, and etching the substrate stack to engrave the further pattern into the substrate.
13. The method of claim 11 , wherein a hard mask layer is disposed on the substrate and the first pattern is applied to the hard mask and the first pattern is etched into the hard mask layer.
14. The method of claim 11 , further comprising a breakthrough etch step before etching the substrate stack to remove an inorganic layer covering exposed regions of the substrate, formed by the Sequential Infiltration Synthesis.