RESEARCH PAPER Photolithography enhancement by incorporating photoluminescent nanoscale cesium iodide molecular dots into the photoresists Tao Tao • Zhi Yang • Yanjie Su • Hao Wei • Poonam Sharma • Liangming Wei • Eric Siu-Wai Kong • Yafei Zhang Received: 4 February 2013 / Accepted: 2 September 2013 / Published online: 15 September 2013 Ó Springer Science+Business Media Dordrecht 2013 Abstract This work demonstrated an enhancement effect of photolithograph by the incorporation of photoluminescent nanoscale cesium iodide molecular dots into ultraviolet photoresists. Cesium iodide molec- ular dots with the size of about 0.4 nm acted as centers of ultraviolet absorption and luminescence which enabled the improvement of the morphology of the figure edges and photosensitivity of photoresist pattern. These pho- toluminescent molecular dots decreased the light inter- ference while increasing the resist sensitization of the photoresist. The detailed mechanism about the enhance- ment effects of photoluminescent molecular dots incor- porated into photoresists on the ultraviolet absorption, photosensitivity, and light interference has been pro- posed. This increased effect in the enhancement of photoresists makes way for their potential use for future nanoscale photolithography. Keywords Cesium iodide  Photoluminescence  Photolithography  Photoresists  Nanopatterning  Photonics Introduction The progress of photolithography is one of the major driving forces behind the Moore’s law, which states that the density of components per integrated circuit doubles at regular time intervals (Schaller 1997). The fast development on the lithographical-patterned devices made a significant contribution toward over the photolithography resolution improvement due to the reduced line edge roughness on the surface of photoresist. Due to this the fidelity of pattern transfer and device performance have been strongly affected as reported in deca-nanometer MOSFETs (Asenov et al. 2003), FinFET (Baravelli et al. 2007), and NAND flash memory array (Vaglio et al. 2012). The surface pattern of photoresist can be influenced by various factors, such as fluctuating energy particle density, local developer density, solubility, and size of polymer molecules. Typically, it can be induced by the standing wave effect in which the reflection of photons from the silicon substrate results in optical interference and consequently standing wave-like concentration of photosensitive compounds in the photoresists (Dill 1975). In addition, photosensitivity of resists is drawing much attention nowadays. Enhanced photo- sensitivity can be achieved by the method in which the trapping of light have been increased on the nano- structure surface of Si wafer (Hwang et al. 2011). The pattern surface morphology and photosensitivity of photoresist are very significant to photolithography enhancement. T. Tao  Z. Yang (&)  Y. Su  H. Wei  P. Sharma  L. Wei  E. S.-W. Kong  Y. Zhang (&) Key Laboratory for Thin Film and Microfabrication of Ministry of Education, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China e-mail: zhiyang@sjtu.edu.cn Y. Zhang e-mail: yfzhang@sjtu.edu.cn 123 J Nanopart Res (2013) 15:1991 DOI 10.1007/s11051-013-1991-9