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HfO 2 nanoparticles stabilized with selected ligands possess high refractive index and low absorbance under 193 nm radiation. These materials combined with an appropriate photopolymer were used as a nanocomposite photoresist. The resulting nanocomposite materials were used successfully for high resolution patterning.

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Exfoliated polyaniline (PANI)/clay nanocomposites were prepared by in-situ polymerization of aniline onto pre-exfoliated water-soluble poly(styrenesulfonic acid-co-aminostyrene) (P(SSA-co-AMS))/ clay nanocomposite or by simple blending of poly(styrenesulfonic acid-g-aniline) (PSSA-g-PANI) with clay. When an aqueous mixture of P(SSA-co-AMS) and clay was treated with 1 M HCl (aq), clay layers are exfoliated into the polymer matrix due to the electrostatic interaction between the positive charge of nitrogen (NH 3 + ) in P(SSA-co-AMS) and the negatively charged surface of clay layers. The electrical conductivity of the nanocomposite is slightly lower than that of pure PSSA-g-PANI, but the thermal stability and coatability of the nanocomposite become better compared with PSSA-g-PANI.

The trend of ever decreasing feature sizes in subsequent lithography generations is paralleled by the need to reduce resist thickness to prevent pattern collapse. Thinner films limit the ability to transfer the pattern to the substrate during etch steps, obviating the need for a hardmask layer and thus increasing processing costs. For the 22 nm node, the critical aspect ratio will be less than 2:1, meaning 40-45 nm thick resists will be commonplace. To address this problem, we have developed new inorganic nanocomposite photoresists with significantly higher etch resistance than the usual polymer-based photoresists. Hafnium oxide nanoparticles are used as a core to build the inorganic nanocomposite into an imageable photoresist. During the sol-gel processing of nanoparticles, a variety of organic ligands can be used to control the surface chemistry of the final product. The different ligands on the surface of the nanoparticles give them unique properties, allowing these films to act as positive or negative tone photoresists for 193 nm or electron beam lithography. The development of such an inorganic resist can provide several advantages to conventional chemically amplified resist (CAR) systems. Beyond the etch resistance of the material, several other advantages exist, including improved depth of focus (DOF) and reduced line edge roughness (LER). This work will show etch data on a material that is ~3 times more etch-resistant than a PHOST standard. The refractive index of the resist at 193 nm is about 2.0, significantly improving the DOF. Imaging data, including cross-sections, will be shown for 60 nm lines/spaces (l/s) for 193 nm and e-beam lithography. Further, images and physical characteristics of the materials will be provided in both positive and negative tones for 193 nm and e-beam lithography.