Chapter 7 - Chemical vapor deposition of C-F low-k materials

Abstract

This chapter focuses on C–F low- κ interlayer dielectric materials, deposited by plasma-enhanced chemical vapor deposition (PECVD). Low- κ film properties and the film deposition rate can be easily controlled by plasma process parameters. The chapter discusses the properties and integration issues of an organic PECVD polymerized material, consisting mainly of carbon, fluorine, and hydrogen, with respect to the semiconductor industry requirements. The lowest dielectric constants (κ≈ 2.0), measured on nonporous materials, are reported from the plasma deposited material group. Other electrical film properties (leakage current density and break down field strength) show excellent values. Plasma induced cross-linking in the low-κ material is responsible for high thermal and mechanical stability of the dielectric films. Its mechanical stability and inertness to solvents, water, and different chemicals are the basis for polishing the dielectric by chemical–mechanical polishing (CMP) process. Both, CMP and good patterning ability are required for the use of C–F polymer dielectric in a Damascene structure, combining low-κ insulator with copper lines. Due to the compatibility of C–F low-κ dielectric deposition and patterning with present integrated circuit (IC) technology, C–F polymers, deposited by PECVD process are promising candidates for later application as low-kinterlayer dielectric.