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.

中文翻译：

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使用X射线反射率测量低k电介质的真空紫外吸收光谱

在等离子处理期间，低k电介质会暴露于高水平的真空紫外线（VUV）辐射下，这可能会严重损坏电介质材料。VUV引起的损伤的程度和性质取决于VUV光子的能量和能量密度。在这项工作中，我们使用镜面X射线反射率（XRR）检查了低k有机硅玻璃的VUV吸收光谱。将低k SiCOH薄膜暴露于7-21 eV能量的同步加速器VUV辐射中，并通过拟合XRR实验数据提取VUV辐照薄膜的密度与深度的关系。结果表明，VUV诱导的损伤层的深度是光子能量的函数。在7和11 eV之间，受损层的深度从110 nm急剧减小到60 nm，然后在21 eV时逐渐增加到85 nm。低k膜中的最大VUV吸收发生在11至15 eV之间。发现受损层的深度随膜的孔隙率而增加。