Characterization of parylene-N thin films for low-k VLSI applications

Parylene-N thin films were characterized from the viewpoint of advanced VLSI intermetal dielectric applications. All films were deposited in a prototype production system that included a vacuum chamber, electrostatic cold chuck and a parylene vapor delivery system. Chuck temperatures as low as -30 degrees C were achieved. The deposition rate was found to be strongly dependent on wafer temperature, increasing dramatically as wafer temperature is reduced. Deposition rate was also strongly dependent on the parylene vapor flow rate and process pressure. These strong dependencies require that extreme care be taken to achieve production worthy repeatability. A number of film properties were measured including; dielectric constant, refractive index, stress, adhesion, conformality, OH-content, metals-content and thermal stability.