Effect Of Annealing On Structures And Properties Of CH₄-doped SiCOH Films

In order to address the problems caused by device-dimension continuous shrinking in ultralarge-scale integrated chips,such as signal propagation delay,power consumption,and the cross-link between metal interconnects,porous low-dielectric conatant(low-κ),and ultralow dielectric constant(ultralow-κ,κ＜2)materials have received more close attention.SiCOH films are prepared by electron cyclotron resonance chemical vapor deposition (ECR-CVD)by adding methane in decamethylcyclopentasioxane(DS)as source gas.For the SiCOH lowκfilms will have 400 - 450℃thermal treatments at the semiconductor technics,the structure,surface appearance and hydrophobic properties are investigated. The results show that the thermal unstable CH_x groups desorption during the thermal treatment can lead to the linkage between Si-O-Si networks and chains groups and the formation of Si-O-Si cages.As a result,the porosity of SiCOH films can be increased and the surface roughness be decreased.However,the CH,,groups desorption and the structure reform can decrease the thick of the film and hydrophobic property deterioration after desorption.Then after annealing,the desorption of thermal unstable CH_x groups during the thermal treatment can lead to the decrease of leakage current,the variation of SiCOH/Si interface state.