Plasma enhanced atomic layer deposition of SiO2 using space divided plasma system
* Han Sup Uhm1, Hyuckjip Choi2 1 Department of Elctronic and Biological Physics, Kwangwoon University, Korea 2 Department of Electrical and Biological Physics, Kwangwoon University, Korea
A newly-developed Space-Divided Plasma (SDP) Atomic-Layer Deposition (ALD) system with a wide range of process temperature is presented here by both rotating the substrate and dividing the area of Source/Purge/Reactant-Plasma/Purge (PEALD). Characteristic properties of SiO2 thin-film composition by O2 Plasma for reactant and BDEAS for Si source at low process temperature ranging from 50°C to 400°C are investigated. A high-quality film deposition at low temperature was established in this process, accomplishing a high productivity. The result shows the uniformity less than 1 % (at 300mm wafer) , step coverage more than 95 % at aspect ratio of 60:1, wet etch rate 0.48Å/sec at 400°C (100:1 HF). This SiO2 film shows a better wet-etching rate compared to high-temperature oxide film. Also, TEM pattern image of amorphous carbon under-layer is compared with thermal and SDP methods. There is no sub-layer damage, meaning damage free of SDPALD oxide by plasma process. Moreover, it was found that N doping influences not only upon N2-treatment time, but upon doping processing temperature. The SDP oxide film prepared by ALD method at 100°C showed average surface roughness comparable to those of the films deposited normal PEALD method.