Ultra-Low Dielectric Permitfivity Ceramics and Composites for Packaging Applications

To accomplish the interconnect systems which will be required in the next generation of very high speed Ga:As digital ICs, it will be necessary to use strip line techniques for signal traces which must be deposited over very low permittivity dielectric substration. Materials with relative dielectric permittivities k 〈 3.0 and very low loss tangent up to microwave frequencies will be required. For ceramic systems such values are impossible to achieve in single phase monoliths, and composite approaches are required. Techniques for processing ceramic insulators which permit the introduction of controlled pore structures are discussed. The introduction of pores degrades some other desirable properties of the ceramic such as mechanical strength and thermal conductivity so that control of both scale and location of pores is desirable.Materials investigated include sol-gel processed silica films and monoliths, reactively sputtered silica, etched glass compositions and Macro-Defect-Free (MDF) cements.