【摘要】 用等离子体化学气相淀积系统制备了一种新颖的SiCOF/a-C∶F双层低介电常数介质薄膜,并用红外光谱表征了该薄膜的化学结构.通过测量介质的折射率发现该薄膜长时间暴露在空气中,其光频介电常数几乎不变.然而,随退火温度的增加,其光频介电常数则会减小.基于实验结果讨论了几种可能的机理.二次离子质谱分析表明在Al/a-C∶F/Si结构中F和C很容易扩散到Al中,但在Al/SiCOF/a-C∶F/Si结构中,则没有发现C的扩散,说明SiCOF充当了C扩散的阻挡层.分析还发现在SiCOF和a-C∶F之间没有明显的界面层.更多还原

【Abstract】 A novel double-layer film of SiCOF/a-C∶F with a low dielectric constant is deposited using a PECVD system.The chemical structure of the film is characterized with Fourier transform infrared spectroscopy (FTIR).The measurements of the film refractive index reveal that the optical frequency dielectric constant (n~2) of the film is almost constant as a function of air exposure time,however,with increasing annealing temperature,the value of n~2 for the film decreases.Possible mechanisms are discussed in detail.The analysis of SIMS profiles for the metal-insulator-silicon structures reveal that in the Al/a-C∶F/Si structure,the annealing causes a more rapid diffusion of F in Al in comparison with C,but there is no obvious difference in Si.In addition,no recognizable verge exists between SiCOF and a-C∶F films,and the SiCOF film acts as a barrier against the diffusion of carbon into the aluminum layer.更多还原