The prediction of the effects on the dielectric constant in thin film dielectrics is of interest in a variety of electronic applications ranging from microelectronics to displays and MEMS applications. This paper discusses the link between the molecular structure of a silicate spin-on dielectric and the final processed dielectric constant by relating trends in the calculated dielectric constant using Density Functional Theory to measurements made on thin films produced during formulation and cure studies. For this investigation, silanol and water content, film density and stress were varied both computationally and experimentally in order to understand the trade-off contributing toward the final dielectric constant. It was found that there is a non-trivial relationship between all these variables which relates back to the molecular structure of the final material, expressed by the density and the stress state of the material. This underlines the importance of finding stable processes in order to produce reproducible films.
A spin-on sacrificial 193 nm UV absorbing organosiloxane film was developed to facilitate ArF photoresist (PR) patterning. To improve lithographic compatibility with acrylate based photoresists, different performance additives were evaluated as photoresist adhesion promoter. The results suggested that the type and loading of the photoresist adhesion promoter had a large impact on the profile and focus latitude of the patterned photoresist features. An efficient photoresist adhesion promoter candidate was identified, which has minimum impact on other solution and film properties. This work has led to the development of DUO 193 organosiloxane based bottom anti-reflective coating. Application of this film as a blanket level bottom anti-reflective coating or as a fill material for via first trench last (VFTL) dual damascene patterning is possible. The SiO structure intrinsic to this film provides a high degree of plasma etch selectivity to the thin ArF photoresists in use today. Furthermore, an equivalent plasma etch rate between DUO 193 and the low dielectric constant SiOCH films used as the dielectric layer in the backend Cu interconnect structure is possible without compromising the photoresist etch selectivity. Equivalent etch rate is necessary for complete elimination of the “fencing” or “shell” defects found at the base of the etched trench feature located at the perimeter of the top of the via. Advanced ArF PR features of 100 nm in width (and smaller) have been routinely patterned on DUO 193 film. Via fill, plasma etch rate, wet etch rate, ArF PR patterning and shelf life data will be discussed in this presentation.
A sacrificial, spin-on 193nm UV absorbing organosiloxane film has been developed to enable via first trench last (VFTL) copper dual-damascene patterning. The SiO structure intrinsic to the Duo193 BARC provides the required plasma etch selectivity to the thin ArF photoresists in use today. Furthermore, an equivalent plasma etch rate between Duo193 and the low dielectric constant SiOCH films, used as the dielectric layer in the backend Cu interconnect structures, is possible without compromising the photoresist etch selectivity. An equivalent etch rate is a necessary for complete elimination of 'fence' or 'shell' defect found with organic-based BARCs. This work has led to the development of Duo193 organosiloxane based bottom antireflective coatings. Tunable formulation variables, such as BARC solution pH to modulate film acidity, can have a significant effect on bulk and surface film properties. In addition to solution pH, the effect of BARC film bake temperature on wet chemical strip rates was also studied. ArF lithography, plasma etch and selective removal are discussed to focus on the process integration benefits of the planarizing, organosiloxane BARC material.
Attempts are being made to produce nonlinear optical (NLO) polymers by capitalizing on self- alignment properties of peptides by the formation of a beta pleated sheet. Such polymers contain both hydrophilic chromophores and hydrophobic side chains in which selective wetting on a water surface using Langmuir-Blodgett techniques creates a first-order approximation of the oriented film. Assembly to the planar beta pleated sheet structure should further enhance the oriented chromophoric structure of the extended mass. However, this requires stabilization through both hydrogen bonding and through energetically stable conformations. It is this stabilization which will favor the enhanced chromophore alignment during the deposition processes. Previous experimental peptides using leucine-based hydrophobic groups and dinitrophenyl-based hydrophilic chromophores have shown limited success in formation of the oriented films. Because it is desirable to be able to predict the effects of the side chain on orientational properties we have added molecular modeling to our general synthetic strategies, in order to analyze the possible affects of the primary structure on the beta sheet.