Irradiation-Source-Dependent Tone Conversion in Dry-Deposited Halogenated Amorphous Zeolitic Imidazolate Framework Resists for Electron-Beam and Extreme Ultraviolet Lithography @Applied Materials & Interfaces

Dry-deposited metal–organic resists are key enablers for advanced patterning processes in next-generation semiconductor manufacturing. Here, we report halogenated amorphous zeolitic imidazolate framework (a-ZIF) resists deposited entirely by a dry process, which exhibit a pronounced irradiation-source-dependent tone conversion. Smooth a-ZIF films were grown by chemical vapor deposition (CVD) using 4,5-diiodoimidazole (DI-Im) precursors. Partial in situ thermal decomposition of DI-Im produces a ternary linker mixture (DI-Im, 4-iodoimidazole, imidazole), promoting the growth of uniform, amorphous films. Under electron-beam (e-beam) exposure, the resist operates in a positive-tone mode with high sensitivity (D₅₀ = 0.15 mC cm^-2, comparable to commercial PMMA resists) and resolves 100 nm line-and-space and 80 nm contact-hole patterns. In contrast, EUV exposure yields high sensitivity in negative-tone development (D₅₀ = 65 mJ cm^-2) and exhibits a nonmonotonic dose–thickness response in positive-tone development. We demonstrate positive-tone EUV patterning of 90 nm line-and-space features. X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopy trace the tone conversion to distinct reaction pathways: high-energy primary electrons under e-beam exposure drive imidazole ring decomposition into soluble polar fragments, giving rise to the positive-tone response, whereas the low-energy electrons generated under EUV cleave C–I bonds while retaining the ring, and the resulting poorly soluble recombination products account for both the negative-tone behavior and the nonmonotonic positive-tone response. Identifying the electron-energy regimes and reaction pathways responsible for each behavior provides a basis for engineering the resist response through linker design. These results illustrate that electron-beam exposure cannot serve as a universal chemical proxy for EUV lithography.

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