Metal Oxide Nanoparticle Photoresists for EUV Patterning Jing Jiang, Souvik Chakrabarty, Mufei Yu and Christopher K. Ober* Department of Material Science and Engineering, Cornell University, Ithaca, NY 14853 Previous studies of methacrylate based nanoparticle have demonstrated the excellent pattern forming capability of these hybrid materials when used as photoresists under 13.5 nm EUV exposure. HfO 2 and ZrO 2 methacrylate resists have achieved high resolution (~22 nm) at a very high EUV sensitivity (4.2 mJ/cm 2 ). Further investigations into the patterning process suggests a ligand displacement mechanism, wherein, any combination of a metal oxide with the correct ligand could generate patterns in the presence of the suitable photoactive compound. The current investigation extends this study by developing new nanoparticle compositions with trans- dimethylacrylic acid and o-toluic acid ligands. This study describes their synthesis and patterning performance under 248 nm KrF laser (DUV) and also under 13.5 nm EUV exposures (dimethylacrylate nanoparticles) for the new resist compositions. Keywords: nanoparticle, EUV, photoresist, metal oxide 1. Introduction The progression of Moore’s law demands shrinkage in dimension of the technology nodes to sub 25 nm features. Currently, the industry has been relying on 193 nm immersion lithography with double patterning to print finer features on resist materials. Demands for further reduction in pattern dimension would require multiple patterning steps at the given 193 nm wavelength, leading to a manifold increase in processing expenditure. Recent developments in patterning has shown that EUV radiation at 13.5 nm wavelength holds promise in printing smaller features in a single exposure step. A major drawback of EUV sources is its low power output, which would lead to a decreased throughput in high volume manufacturing. To address this issue, significant studies are being performed aiming at intensifying the EUV power source. Similarly, another approach mitigate the issue of low throughput is to enhance sensitivity of photoresist materials to EUV radiation while still maintaining a high resolution and pattern LER. An initial study on methacrylate based nanoparticle resists have demonstrated enhanced EUV sensitivity with high resolution patterns. 1-3 Gaining insights from prior observations 4 , the present study describes new nanoparticle compositions, using ligands of different strengths which led to resists with extremely high EUV sensitivity. Extending the study further, nanoparticles with o-toluic acid (strong ligand, figure 1b) was successfully synthesized and evaluated for patterning under 248 nm KrF laser (DUV). 2. Materials and Methods 2.1. Materials The respective isopropoxide of hafnium and zirconium were obtained from Sigma Aldrich. Dimethylacrylic acid, o-toluic acid, photoactive compounds and reagent grade solvents were purchased from Sigma-Aldrich and used as received, without further purification. Silicon wafers were purchased from WRS materials. Nanoparticles were synthesized by sol-gel technique as described previously. Photoresist formulation and film formation has been reported Figure 1. trans-dimethyl- acrylic acid (a) and ortho- toluic acid (b) a b Journal of Photopolymer Science and Technology Volume 27, Number 5 (2014) 663–666 © 2014SPST Received April 2, 2014 Accepted May 15, 2014 663