Copolymer for use in chemical amplification resists
AssigneeInternational Business Machines Corporation
InventorHiroshi Ito
Life of this patent
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Abstract
A copolymer is provided for use in a lithographic photoresist composition, particularly a chemical amplification photoresist. In a preferred embodiment, the copolymer is substantially transparent to deep ultraviolet radiation, i.e., radiation of a wavelength less than 250 nm, including 157 nm, 193 nm and 248 nm radiation, and has improved sensitivity and resolution. In one embodiment, the copolymer is comprised of an α-cyano- or an α-trifluoro-methacrylate monomer unit and a vinyl ether monomer unit. A lithographic photoresist composition containing the fluorinated copolymer is also provided, as is a process for using the composition to generate resist images on a substrate, i.e., in the manufacture of integrated circuits or the like.
Claims25
A process for generating a patterned structure on a surface, comprising the steps of:
- (a) generating a resist image on a substrate using a photoresist composition comprised of a copolymer synthesized from a first monomer having the structure of formula (I)
- wherein
- R1 is H, F, CN, CH3, CF3, CF2H, or CFH2;
- R2a and R2b are independently H or F;
- and
- R3 is CN or COOR, wherein R is selected from the group consisting of H, C1-12 alkyl and C1-12 fluoroalkyl, or is selected so as to render R3 acid-cleavable, with the proviso that when R3 is CN, then R1 is CF3 and R2a and R2b are H;
- and
- a second monomer having the structure of formula (II)
- wherein
- R4 is H, C1-12 alkyl, or C3-15 alicyclic,
- R5 is C1-12 alkyl, C1-12 alkyl substituted with 1-12 fluorine atoms and 0-2 hydroxyl groups, or C3-15 alicyclic, or R4 and R5 together form a five-, six-, or seven-membered ring,
- R6 is H, C1-12 alkyl, or C1-12 fluoroalkyl, or R4 and R6 together form a five-, six-, or seven-membered ring,
- R7 is H, C1-12 alkyl, or C1-12 fluoroalkyl, or R7 and R5 together represent —X—(CR8R9)n—, in which case R4 and R6 are H, X is O or CH2, n is 1 or 2, R8 and R9 are H, C1-12 alkyl, or C1-12 fluoroalkyl, or together form an oxo moiety (═O), with the proviso that when R8 and R9 together form ═O, n is 1;
- (b) transferring the resist image to the underlying substrate.
A process for transferring a resist image on a substrate to an underlying material, comprising the steps of:
- (a) forming the resist image by a process comprising:
- (i) coating a substrate with a film of a photoresist comprised of a radiation-sensitive acid generator and a copolymer synthesized from a first monomer having the structure of formula (I)
- wherein
- R1 is H, F, CN, CH3, CF3, CF2H, or CFH2;
- R2a and R2b are independently H or F;
- and
- R3 is CN or COOR, wherein R is selected from the group consisting of H, C1-12 alkyl and C1-12 fluoroalkyl, or is selected so as to render R3 acid-cleavable, with the proviso that when R3 is CN, then R1 is CF3 and R2a and R2b are H;
- and
- a second monomer having the structure of formula (II)
- wherein
- R4 is H, C1-12 alkyl, or C3-15 alicyclic,
- R5 is C1-12 alkyl, C1-12 alkyl substituted with 1-12 fluorine atoms and 0-2 hydroxyl groups, or C3-15 alicyclic, or R4 and R5 together form a five-, six-, or seven-membered ring,
- R6 is H, C1-12 alkyl, or C1-12 fluoroalkyl, or R4 and R6 together form a five-, six-, or seven-membered ring,
- R7 is H, C1-12 alkyl, or C1-12 fluoroalkyl, or R7 and R5 together represent —X—(CR8R9)n—, in which case R4 and R6 are H, X is O or CH2, n is 1 or 2, R8 and R9 are H, C1-12 alkyl, or C1-12 fluoroalkyl, or together form an oxo moiety (═O), with the proviso that when R8 and R9 together form ═O, n is 1
- (ii) exposing the film selectively to a predetermined pattern of radiation so as to form a latent, patterned image in the film;
- and
- (iii) developing the latent image with a developer;
- (b) etching one or more layers of material underlying the resist layer at spaces in the pattern such that a patterned material layer or substrate section is formed;
- and
- (c) removing any remaining resist from the substrate.
Dependencies are inferred from the claim text.