Measurement of the vacuum-ultraviolet absorption spectrum of low-k dielectrics using X-ray reflectivity

作者：Choudhury F A; Nguyen H M; King S W; Lee C H; Lin Y H; Fung H S; Chen C C; Li W; Benjamin D; Blatz J M; Nishi Y; Shohet J L^*

来源：Applied Physics Letters, 2018, 112(8): 082902.

DOI：10.1063/1.5025180

During plasma processing, low-k dielectrics are exposed to high levels of vacuum ultraviolet (VUV) radiation that can cause severe damage to dielectric materials. The degree and nature of VUV-induced damage depend on the VUV photon energies and fluence. In this work, we examine the VUV-absorption spectrum of low-k organosilicate glass using specular X-ray reflectivity (XRR). Low-k SiCOH films were exposed to synchrotron VUV radiation with energies ranging from 7 to 21 eV, and the density vs. depth profile of the VUV-irradiated films was extracted from fitting the XRR experimental data. The results show that the depth of the VUV-induced damage layer is a function of the photon energy. Between 7 and 11 eV, the depth of the damaged layer decreases sharply from 110 nm to 60 nm and then gradually increases to 85 nm at 21 eV. The maximum VUV absorption in low-k films occurs between 11 and 15 eV. The depth of the damaged layer was found to increase with film porosity. Published by AIP Publishing.

• 出版日期2018-2-19
• 单位清华大学