掺CH4的SiCOH低介电常数薄膜结构与介电性能研究

以十甲基环五硅氧烷和甲烷作为反应气体，采用电子回旋共振等离子体化学气相沉积(ECR-C VD)方法制备了k = 2.45，485℃下的热稳定性优良的SiCOH低介电常数薄膜.通过薄膜结构的 FTIR谱分析，比较了十甲基环五硅氧烷(D5)液态源和不同甲烷流量下制备的薄膜的键结构差 异，发现在沉积过程中甲烷含量的增大，一方面有利于D5源环结构的保留，另一方面有利于 薄膜中形成高密度的CH_n基团.高密度碳氢大分子基团的存在降低了薄膜密度， 结合薄膜中形成的本构孔隙、低极化率Si—C键以及—OH键减少的共同作用，导致薄膜介电 常数的降低. 关键词： 低介电常数 SiCOH薄膜 碳氢掺杂

Effect of CH4-doping on configuration and dielectric properties of SiCOH low-k films

Carbon-doped oxide materials (SiCOH films) with k of 2.45 and good thermal stability at temperature 485℃ are prepared by electron cyclotron resonance chemical vapor deposition (ECR-CVD) from the mixture of decamethylcyclopentasioxane (D5, ［Si(CH₃)₂O］₅) and methane (CH₄). T he chemical structures of D5 as a liquid source and films deposited with differe nt methane flux are studied by Fourier transform infrared spectroscopy. The resu lts indicate that the increase of methane is of great advantage to the reservati on of ring structure of D5 as well as the formation of high density CH_{n fragments in films. The decrease of dielectric constant is induced by the com bined action of several factors: lower density of films caused by high density o f CHn fragments and formation of intrinsic pores, lower polarization caused by the formation of Si-C bond and decrease of-OH bonds.}