NOVEL LOW-K DIELECTRICS BASED ON DIAMOND-LIKE CARBON MATERIALS

Hydrogenated diamondlike carbon (DLC) and fluorine containing DLC (FDL C) were investigated for their potential applications as low Ic dielec trics for the back end of the line interconnect structures in ultralar ge scale integrated circuits. It was found that the dielectric constan t (k) of DLC can be varied between <2.7 and >3.4 by changing the depos ition conditions. The thermal stability of the DLC films was found to be correlated to the values of the dielectric constant, decreasing wit h decreasing k. Only DLC films having dielectric constants k > 3.3 app eared to be stable to anneals of 4 h at 400 degrees C in a nonoxidizin g environment. However these films were characterized by stresses high er then 600 MPa. FDLC films, thermally more stable at 400 degrees C th an the DLC films with k > 3.3, could be prepared with dielectric const ants below 2.7 and internal stresses <200 MPa. Such FDLC films are thu s promising candidates as a low k interconnect dielectric.