Adhesion layers for EUV lithography
New lithographic compositions for use as EUV adhesion layers are provided. The present invention provides methods of fabricating microelectronics structures using those compositions as well as structures formed by those methods. The method involves utilizing an adhesion layer immediately below the photoresist layer. The adhesion layer can either be directly applied to the substrate, or it can be applied to any intermediate layer(s) that may be applied to the substrate, such as an alpha-carbon, spin-on carbon, spin-on silicon hardmask, metal hardmask, or deposited silicon layer. The preferred adhesion layers are formed from spin-coatable, polymeric compositions. The inventive method improves adhesion and reduces or eliminates pattern collapse issues.
1. A method of forming a structure, said method comprising:
providing a substrate, said substrate including one or more intermediate layers thereon, said one or more intermediate layers comprising:
a spin-on carbon layer;
a hard mask layer;
both said spin-on carbon layer and said hardmask layer, said hardmask layer being on said spin-on carbon layer; or
both said hardmask layer and said spin-on carbon layer, said spin-on carbon layer being on said hardmask layer;
forming an adhesion layer on said spin-on carbon layer or on said hardmask layer, said adhesion layer:
having an average thickness that is greater than a monolayer but less than 9 nm;
a metal content of less than about 0.001% by weight, based upon the total weight of the adhesion layer taken as 100% by weight; and
being formed from a composition comprising a component dissolved or dispersed in a solvent system, said component being chosen from:
polymers comprising monomers chosen from glycidyl acrylate, glycidyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, hydroxy propyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, tert-butyl methacrylate, or mixtures thereof;
styrenes;
epoxies;
novolacs;
silanes;
cyanurates;
tris(2,3-epoxypropyl)isocyanurate;
vinyl compounds grafted with a functionalized carboxylic acid moiety, a chromophore, or both;
polymers comprising a vinyl monomer grafted with a functionalized carboxylic acid moiety, a chromophore, or both; or
mixtures thereof;
forming a photoresist layer on said adhesion layer; and
subjecting at least a portion of said photoresist layer to EUV radiation.
2. The method of claim 1 , wherein:
said spin-on carbon layer comprises greater than about 50% by weight carbon; and
said hardmask layer comprises a polymeric hardmask layer.
3. The method of claim 1 , wherein said photoresist layer is a chemically amplified photoresist layer.
4. The method of claim 1 , wherein said composition comprises about 98% to about 99.99% by weight of said solvent system, based on the total weight of the composition taken as 100% by weight.
5. The method of claim 1 , wherein said solvent system comprises a solvent chosen from propylene glycol methyl ether acetate, propylene glycol methyl ether, propylene glycol n-propyl ether, ethyl lactate, cyclohexanone, gamma butyrolactone, methyl isobutyl carbinol, propylene glycol ethyl ether, or mixtures thereof.
6. The method of claim 1 , wherein said spin-on carbon layer or said hardmask layer is on said substrate.
7. The method of claim 6 , wherein said hardmask layer comprises silicon.
8. The method of claim 1 , wherein said adhesion layer is on said hardmask layer, said hardmask layer is on said spin-on carbon layer, and said spin-on carbon layer is on said substrate.
9. The method of claim 1 , wherein said forming an adhesion layer comprises:
spin coating said composition on said spin-on carbon layer or on said hardmask layer; and
baking said composition to form said adhesion layer.
10. The method of claim 1 , wherein said photoresist layer comprises metal.
11. The method of claim 10 , wherein said photoresist layer comprises one or both of a metal oxide or an organometallic compound.
12. The method of claim 1 , wherein said photoresist layer does not comprise metal.
13. The method of claim 1 , wherein said component comprises a polymer comprising monomers chosen from styrenes, silanes, cyanurates, or mixtures thereof.
14. The method of claim 1 , wherein said component is chosen from polymers comprising monomers chosen from, glycidyl acrylate, glycidyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, hydroxy propyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, tert-butyl methacrylate, or mixtures thereof.
15. The method of claim 1 , wherein said component is chosen from styrenes, epoxies, novolacs, silanes, cyanurates, tris(2,3-epoxypropyl)isocyanurate, or mixtures thereof.
16. The method of claim 1 , wherein said component comprises a polymer selected from the group consisting of
17. The method of claim 1 , further comprising forming a pattern in said photoresist layer after said subjecting at least a portion of said photoresist layer to EUV radiation.
18. The method of claim 17 , further comprising transferring said pattern to said adhesion layer and to said spin-on carbon layer or to said hardmask layer.
19. The method of claim 17 , wherein said spin-on carbon layer or said hardmask layer is on said substrate, and further comprising transferring said pattern to said adhesion layer and to said spin-on carbon layer or to said hardmask layer and to said substrate.
20. The method of claim 17 , wherein said pattern has a resolution of less than about 40 nm half pitch.