Automatic production of microcircuit blocks

Abstract

It is well known that capacitance in the metallization is becoming too great to allow the continued use of SiO2 as the intermetal dielectric below about the 0.25 μm technology node. One class of many possible replacements for SiO2 are organic polymers. Organic polymers are not drop-in replacements, however, and their successful integration into functional circuits requires new fabrication procedures and integration schemes. The Embedded Dielectric Scheme offers a sound evolutionary path for their successful integration into a subtractive etch, aluminium-based integrated circuit. The Embedded Dielectric Scheme effectively lowers total capacitance and the line-line/total capacitance ratio while minimally changing the rest of the metallization fabrication processes, particularly via formation. Vapor-deposited polymers like parylene-n which are conformably deposited integrate more easily into the Embedded Dielectric Scheme than nonconformal spin-on dielectric films. Parylene-n copolymers with dielectric permittivities as low as 2.3 also are excellent candidate materials for use in the Embedded Dielectric Scheme; they also have equivalent thermal stability as the homopolymer. New copolymers with comonomers of different functionality should improve both the adhesion and thermal stability of the intermetal dielectric.