Properties and Gap-Fill Capability of HPD-CVD Phosphosilicate Glass Films for Subquarter-Micrometer ULSI Device Technology

摘要

Properties of phosphosilicate glass films deposited at high-density plasma (HDP) conditions have been studied for film application as a premetal dielectric in subquarter-micrometer ultralarge scale integration (ULSI) device technology. Films were more dense and more stable compared to borophosphosilicate glass films, and provided void-free gap-fill for "rectangular" in section device structures with gap spacing G_(critical) ≈ 0.16 μm and aspect ratio AR_(critical) ≈ 3.1. Results of gap-fill capability study and previously published data have been described with empirical linear dependence AR_(critical) = κ * G_(critical), where κ was found to be a function of HDP chemical vapor deposition (HDP-CVD) conditions. It has been shown that to achieve void-free gap-film capability of films for structures with gaps as low as 0.1 μm and aspect ratios about four and higher, top corner rounding of structures and sidewall slope less than 90° must be implemented. An approach to evaluate an impact of structure rounding in HDP-CVD gap-fill capability has been proposed.