Study On The Preparation And Dielectric Properties Of PPSQ Porous Thin Films

As ultra-large-scale integration(ULSI) of integrated circuits develop,CVD-SiO₂ as the traditional low dielectric material within intermetal applications has not sufficed the demand of continuing development of IC industry.Silicon-based Organic/Inorganic materials have been widely studied in the semiconductor industry.And silsesquioxane (SSQ) is one kind of the most promising materials for intermetal dielectric applications.In this paper,low dielectric materials and the methods of reducing dielectric constant(k) were summarized.Low dielectric films based on PPSQ were prepared by a spin-coating technlogy following a series of processes.In these processes,the films were fabricated through PPSQ as molecular template,which used Tw-20 as pore generating template and Toluene,MIBK as solvent.The films were then cured by four steps.In this paper,several properties of the films were also investigated.The absorbing moisture ratio of the thin PPSQ-based films was proved to be low.When Tw-20 loading approaches nearly 30w%via PPSQ,the films has the lowest dielectric constant and the highest porositie.The Spectroscopic Ellipsometry has tested the data of dielectric constants and porosities.AFM and SEM investigated surface and cross section morphology of porous films,which show the surface of films is relatively compact and plane.The anti-cracking probility of the films is also good,which can be comfirmed by the least 2-3μm's anti-cracking thickness.Finally, we attempt to estimate the pore radius distribution and pore structure by GISAXS.The point that will be utlizied for IC industry can be by former investigated probilities indicate that PPSQ as a promising low-k material have a excellent application foreground,which make the next study on interlinkage technics will more expediently.