同步辐射光激励的二氧化硅薄膜刻蚀研究

Synchrotron radiation stimulated etchingof SiO_2 thin films

利用热氧化法在硅晶片上生长SiO2薄膜,结合光刻和磁控溅射技术在SiO2薄膜表面制备接触型钴掩模,通过掩模方法在硅表面开展了同步辐射光激励的表面刻蚀研究,在室温下制备了SiO2薄膜的刻蚀图样.实验结果表明:在同步辐射光照射下,通入SF6气体可以有效地对SiO2薄膜进行各向异性刻蚀,并在一定的气压范围内,刻蚀率随SF6气体浓度的增加而增加,随样品温度的下降而升高;如果在同步辐射光照射下,用SF6和O2的混合气体作为反应气体,刻蚀过程将停止在SiO2/Si界面,即不对硅刻蚀,实现了同步辐射对硅和二氧化硅两种材料的选择性刻蚀;另外,钴表现出强的抗刻蚀能力,是一种理想的同步辐射光掩模材料.

The synchrotron radiation （SR） stimulated etching of SiO2 thin film surface was investigated with a contact cobalt mask, and the etched pattern of SiO2 thin films on silicon was made. The SiO2 thin film was grown on silicon surface by thermal oxidation. The contact cobalt mask was fabricated on SiO2 thin film by combining the techniques of photolithography and RF-magnetron sputtering. In the experiment, the anisotropic etching of SiO2 was effectively achieved by SR radiation with SF6 as the reaction gas. The etching rate increased with increasing gas pressure of SF6 in a certain range, and with decreasing the substrate temperature. Under SR irradiation with flowing SF6 and O2 did not etch the silicon crystal and the etching stopped completely at the SiO2/Si interface. Furthermore, the Co provided high resistance against the SR etching, indicating that Co is an ideal mask material for the synchrotron radiation stimulated etching.