AVS 57th International Symposium & Exhibition
    Thin Film Thursday Sessions
       Session TF-ThP

Paper TF-ThP16
Control of Reflectivity at Substrate/Resist Interface of Nanometer-scaled Devices by Inorganic Bottom Anti-Reflection Coating (BARC)

Thursday, October 21, 2010, 6:00 pm, Room Southwest Exhibit Hall

Session: Thin Film Poster Session II
Presenter: S.-Y. Kim, Korea Polytechnic College IV, Republic of Korea
Authors: S.-Y. Kim, Korea Polytechnic College IV, Republic of Korea
N.-H. Kim, Chonnam National University, Republic of Korea
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As the device has became highly integrated, the more accurate critical dimension (CD) was demended. High contrast resit was also required for the exposure threshold effect. However in this case, the reflectivity between substrate and resist became higher; therefore, the CD swing curve was intesified which was directly influenced by the change of resist thickness. Lastly, the resist notching phenomenon was appeared, which was caused by the reflectivity owing to the shape of sub-layer. It is very important to control the reflectivity between substrate and resist for the precise CD control. The bottom anti-reflective coating (BARC) is one of the most widely used methods. The conventional inorganic BARC has been employed in the metal pattern process of μm-scaled devices with oxynitride. Because the more accurate CD control is necessary for the nm-scaled devices, the resist thickness, the conditions of reflectivity and absorption coefficient, and metal stack as a sub-layer were changed. The standing wave was also observed in the resist profile after metal pattern process of nm-scaled devices. Therefore, the optimization of inorganic BARC was investigated for the application to the nm-scaled devices with the changes of resist thickness and sub-layer. The reflectivity in the interface between BARC (oxynitride) and resist was under the control of thickness, refractive index, and absorption coefficient. The refractive index and absorption coefficient were investigated by a function of the SiH4/N2O gas flow rate, which is the main control factor of the refractive index and absorption coefficient, in oxynitride deposition. Computational simulation was performed in order to obtain the reflectivity in the interface of BARC and resist with changes of the optical factors. The optimum thickness, refractive index, and absorption coefficient were obtained for the minumum reflectivity of oxynitride. The simulated results were sucessfully applied to the experiments, which was confirmed by the cross-sectional SEM. There is no standing wave in this optimum condition.