紫外辐照对超低介电常数SiCOH薄膜组成与机械性能的影响

Effect of ultraviolet irradiation on the composition and mechanical properties of ultra-low dielectric constant SiCOH films

采用紫外光辐照超低介电常数多孔SiCOH薄膜,研究不同照射时间对薄膜结构和性能的影响。采用动态纳米压入技术测量薄膜的力学性能,发现随照射时间增加,薄膜的模量(Er)和硬度(H)不断提高。当辐照时间增至6h时,薄膜力学强度分别达到Er约7.4GPa,H约1.0GPa。傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)分析表明紫外辐照处理能够使薄膜样品中发生键的断裂与重新结合,从而改变了薄膜骨架的交联密度和刚性,进而提高力学性能。但介电性能并未受到明显影响,紫外辐照6h后,k值仅从2.0增至2.2。

Ultra-low dielectric constant porous SiCOH（P-SiCOH） film was irradiated with ultraviolet（UV） light to improve mechanical properties measured by nanoindention technique.As the time prolonged,the reduced elastic modulus（Er） and hardness（H） of samples increased.When the irradiation time was increased to 6h,Er and H reached to about 7.4 and 1.0GPa respectively.The Fourier transform infrared（FT-IR） and X-ray photoelectron spectroscopy（XPS） analyses indicated the cross-link density and stiffness of films increased because UV irradiation caused the breakage and rebond in the bonding structure of P-SiCOH films.However,UV treatment did not influence the dielectric constant（k） significantly.After 6h irradiation,the k was increased to 2.2 which showed 2.0 for non-irradiation film.