In this study, low-dielectric constant (low-k) SiOC(H) films deposited using conventional plasma-enhanced chemical vapor deposition (PECVD) by varying flow rates of the deposition precursors were investigated through various characterization techniques. The used deposition precursors were DEMS and ATRP, which acted as a network matrix and a sacrificial porogen, respectively. Experimental results indicate that the flow rates of both DEMS and ATRT precursors influenced the properties of the resulting porous low-k SiOC(H) films, but the former caused a larger impact. For porous low-k SiOC(H) films deposited with an increase of DEMS flow rate, an enhanced cross-linking was formed, leading to a higher hardness, smaller pore size, better electric performance, and stronger dielectric breakdown strength. However, a higher dielectric constant (k) was the cost. The k values of porous low-k SiOC(H) films with various ATRP flow rates (1700-2500 sccm) remained unchanged, although, the optimized electrical characteristics and reliability were obtained as ATRP flow rate was 2100 sccm.