SiCOH低介电常数薄膜的性质和键结构分析

以十甲基环五硅氧烷为反应源、采用电子回旋共振等离子体化学气相沉积（ECR_CVD）方法制备了具有低介电常数，且电绝缘性能和热稳定性优良的SiCOH薄膜. 通过对富氏变换红外光谱(FTIR)的分析，比较了反应源和薄膜键结构的差异，证实薄膜中一方面保持了源中由Si—O—Si键构成的环结构，另一方面形成了由大键角Si—O—Si键构成的鼠笼式结构，在沉积过程中失去的主要是侧链的—CH3基团. 薄膜经过400℃热处理后，其介电常数由385降低到285，对其FTIR谱的分析指出，薄膜中鼠笼式结构比例的增加可能是薄膜介电常数降低的原因.关键词：低介电常数SiCOH薄膜化学键结构

Characterization and bonding configuration of SiCOH low-k films

Using decamethylcyclopentasioxane (［Si(CH3)2O］5 as liquid precursor, SiCOH films, which have low dielectric constant (low k), good insulating ability and thermal stability, were prepared by electron cyclotron resonance chemical vapor deposition (ECR_CVD). The FTIR spectra of the films were measured to find the difference of bond structures between SiCOH films and DM5 source. It was verified that the Si—O—Si cyclic structure was retained in SiCOH films,while _CH3 radicals were lost during the deposition. The dielectric con stant decreased from 385 to 285 after the film was annealed in 400℃. With t he analysis of the bond structure of the film as deposited and annealed, we can infer that the increased content of cage structure comprised of Si—O—Si bond w ith bigger bond angle may be the reason for decreased dielectric constant.