Kei Hattori

Dry etching technologies for Cr film

We have investigated Cr film etching mechanism systematically in order to minimize CDU (CD Uniformity). As a result, employing our dry etching system ARESTM with optimized etch process we achieved an excellent CDU(3σ) (0.5nm with etch contribution). Cr film has been widely used not only for the light-shielding film at Cr Binary Mask but also as a hard mask film at even the leading edge photomasks (Hard Mask-PSM (Phase Shift Mask)). In case of used as a hard-mask, this plays very important role to determine etching process accuracy and to achieve the minimal CDU. As LSI downscaling and complication of their pattern layouts, the current dry etch technology faces technical challenges such as the difficulties in CD control and will be not sufficient to meet requirements. In this study, each behavior of Cr etching process at the various process parameters and various pattern layouts are investigated.

High-Performance Decomposition and Fixation of Dry Etching Exhaust Perfluoro-Compound Gases and Study of Their Mechanism

We report on the high-performance decomposition and fixation of perfluoro compounds (PFCs) exhausted from dry etching processes and their reaction mechanism with the fixation material prepared from Ca(OH)2 and Al(OH)3 mixture. Using gas chromatography–mass spectrometry (GC–MS), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and other analysis methods, it was found that PFCs were successfully decomposed and fixated by the reaction only with calcium compounds, resulting in calcium fluoride (CaF2). Aluminum compounds existing very close to calcium compounds work as a catalyst so that the reaction progresses at much lower temperatures, in the range of 650 to 750 °C, compared with the direct decomposition by combustion. The reaction mechanism is discussed on the basis of the proposed microscopic reaction model. These results are useful for the development of more efficient abatement systems for the greenhouse gases in the exhaust of dry etching processes.