(A) low dielectric constant spin-on-glass for interlevel dielectric

Abstract

As the feature of a semiconductor chip becomes smaller and the devices become faster, there is a need to improve the interlevel dielectric system so that it will not be the limiting factor in the overall performance of the circuit. This tends to be accomplished by reducing the dielectric constant. Our new low dielectric constant spin-on-glass was designed on the concept of maintaining thermal stability at high temperatures and introducing a fluorin containing compound that lowing the dielectric constant. The spin-on-glass A is consists of tetraethylorthosilicate, dimethyldiethoxysilane and (3,3,3-trifluoropropyl)trimethoxysilane and then the spin-on-glass B is consists of tetraethylorthosilicate, dimethyldiethoxysilane and trimethoxy-1H,1H,2H,2H-tridecafluorooctylsilane. The thickness was measured by α-step and the characterization of SOG was performed by using TGA, FT-IR and DEA. Beside this, the etching rate was measured by using RIE-80 and planarizability was characterized by use of SEM. The introducing of fluorinated trimethoxysilane contributed to lowering the dielectric constant of SOG and we obtained ε of 2.1. We affirmed that the new SOGs have a low dielectric constant as well as a thermal stability at a high temperature and it is achievable of thickness over 1.0㎛ with a good planarization property.