| There is a need to adopt novel low-kappa materials as inter-level-dielectrics (ILDs) in future technology generations. The current challenge is to design low-kappa materials with sufficient mechanical and chemical stability such that they can be easily integrated into current fabrication schemes. Toward this end, this thesis seeks to address two main issues that slow the implementation of low-kappa ILDs, which include (1) chemical stability in ash plasmas and (2) mechanical strength of porous films.; To address the issue of chemical stability, the interactions between plasmas and organosilicate glass (OSG) low-kappa materials that lead to modification were investigated. This work revealed several factors that influence modification in O2, H2, and N2 ash plasmas using various techniques. Using blanket films and techniques such as spectroscopic ellipsometry, x-ray photoelectron spectroscopy (XPS), and infrared spectroscopy, damage to OSG films were correlated with porosity, plasma species, and substrate temperature. Key results from this study were that porous films are much more susceptible to modification than dense films and modification in H2 ash plasmas was highly dependent upon substrate temperature. Less modification occurred at elevated temperatures. In a patterned film study, optical emission (OE) actinometry was used to measure the absolute densities of reactive radical species, and modeling of various plasma parameters (sheath thickness and positive ion mean free path) was used to estimate the significance of ion scattering in several ashing plasmas. Patterned films were ashed in conditions identical to that characterized and then analyzed using angle-resolved XPS (ARXPS). Data from the OE actinometry and modeling were combined with the ARXPS data to identify key factors that influence modification of the OSG. The key result from this study was that ion bombardment, rather than radical species density, played a dominant role in the modification process.; In addition, to address the issue of mechanical strength in porous low-kappa materials, a new low-kappa candidate, oxycarbosiliane (OCS) films, was investigated. OCS films have been shown to have significantly higher (up to 5x) elastic moduli than OSG films. Preliminary results showing how aging and cure conditions impact OCS mechanical strength and other film properties are presented. |
