Paper PS-TuP13
Temperature Dependence on Dry Etching of Al₂O₃ Thin Films in BCl₃/Cl₂/Ar Plasma

Tuesday, October 21, 2008, 6:30 pm, Room Hall D

High-κ gate dielectrics and metal gate electrodes are required for enabling continued equivalent gate oxide thickness scaling, and hence high performance, and for controlling gate oxide leakage for both future silicon and emerging non-silicon nanoelectronic transistors. Significant progress has been achieved in terms of the screening and selection of high-κ insulators, understanding their material and electrical properties, and their integration into CMOS technology. During the etching process, the wafer surface temperature is an important parameter which influences the reaction probabilities of incident species, the vapor pressure of etch products, and the re-deposition of reaction products on feature surfaces. It mainly depends on the chuck temperature, the ion density and ion energy and the exothermicity of the etching reaction. In order to obtain the good etching environment, sudden changes of temperature in the plasma condition during the transition between processes steps should be well controlled .In addition, the true substrate temperature is difficult to monitor. For this reason, the experiment according to the substrate temperature change was progressed. In this study, we investigated that the effect of substrate temperature on the etch rates and selectivity of Al₂O₃ over Si and hard mask materials (such as SiO₂, and Si₃N₄) thin film in inductively coupled plasma in function of (BCl₃/Ar)+ Cl₂ gas mixture ratio, RF power, DC bias and chamber pressure base on the substrate temperature increases from 10 °C to 80 °C,. The chemical reactions on the etched surface were investigated with using x-ray photoelectron spectroscopy. The morphology changes of exposed surface in plasma were investigated with atomic force microscopy. The etch profile was evaluated with SEM as functions of parameters.