Photoresists with reaction anchors for chemical consolidation of resist structures for exposures at 157 nm
View Patent ↗The chemically amplified resist includes a film-forming polymer, a photoacid generator, and a solvent. The film-forming polymer contains acid-labile groups which are eliminated under the action of an acid and liberate a group which brings about an increase in the solubility of the polymer in aqueous alkaline developers. The film-forming polymer has polymer building blocks derived from monomers which are at least monofluorinated and contain an anchor group for the attachment of an amplifying agent. As a result of the fluorination of the polymer building blocks, the transparency of the resist at an exposing wavelength of 157 nm is substantially increased, so that resist structures of increased layer thickness can be represented.
1. A process for consolidating resist structures, which comprises the following method steps:
applying a resist to a substrate, said resist being a chemically amplified resist, including:
a film-forming polymer having a first monomer and a second monomer, and wherein:
said first monomer is at least monofluorinated and contains an anchor group for attachment to an amplifying agent;
said first monomer is selected from the group consisting of monofluorinated or polyfluorinated maleic anhydride, monofluorinated or polyfluorinated itaconic anhydride, monofluorinated or polyfluorinated cyclohexenedi-carboxylic anhydride and monofluorinated or polyfluorinated methacrylic anhydride; and
said second monomer contains acid-labile groups producing alkaline-soluble groups in said polymer through catalytic action of a strong acid;
a photoacid generator; and
a solvent;
drying the resist to form a dried resist;
exposing with radiation having a wavelength of less than 200 nm the dried resist to form an exposed resist containing a latent image;
heating the exposed resist to a first temperature, to thereby transform the latent image into a chemical profile, and liberating polar groups on the polymer;
developing the resist with an aqueous alkaline developer, to detach areas of the chemical profile containing polar groups of the polymer from the substrate, to form a structured resist;
applying an amplifying agent to the structured resist; and washing off excessive amplifying agent.
2. The process according to claim 1 , wherein the amplifying agent is a silicon-containing compound.
3. The process according to claim 1 , wherein the amplifying agent is applied in solution.
4. The process according to claim 1 , which comprises exposing with radiation having a wavelength of 157 nm.