Electrical and adhesion properties of plasma-polymerised ultra-low k dielectric films with high thermal stability
New intermetal dielectrics with dielectric constants (k) less than the dielectric constant of the conventionally used SiO2 (k=3.9) are required for the fabrication of low voltage integrated circuits due to their ability to decrease signal delay time, crosstalk and power dissipation. In this paper results of depositing and investigating CF polymers will be presented. The films were deposited in a single wafer PECVD (plasma enhanced chemical vapor deposition) equipment (Secon 251) using a mixture of C, F and H containing gases. The polymer films are stable for temperatures as high as 425C (shrinkage <1%) maintaining a dielectric constant k even lower than 2.0 (depending on the deposition parameters and annealing processes). Furthermore, the adhesion of the CF films on top of several inorganic materials could be proved by tape test and following CMP processing. ICP patterned vias (polymer thickness: 1 ?m; aspect ratio: 5) showed strong vertical profile.
adhesion dielectric constant cf polymer pecvd low k dielectric