Sputter-deposited low loss Mg2SiO4 thin films for multilayer hybrids

Abstract

Mg2SiO4 (forsterite) thin films grown by rf magnetron sputtering from a ceramic target have been investigated particularly for thin film hybrids requiring a low loss dielectric layer. Understanding of the processing parameters and their correlations to dielectric properties is the main concern of this work. Fundamental parameters, such as working pressure and post-deposition annealing temperature, were found to influence phase evolution, morphology and dielectric properties. For example, polycrystalline alpha-Mg2SiO4 could be obtained above the annealing temperature of 500 degrees C regardless of working pressure. The dielectric constant increased gradually while the dielectric loss showed a reverse trend of decrease with raising annealing temperature to 700 degrees C. Dielectric constant of similar to 6.8 and dielectric loss of similar to 2.8x10(-3) were obtained at 1 MHz from the sample annealed at 700 degrees C. A promising planarized thin film structure for fine line multilevel packaging was demonstrated without any significant inter-diffusion and damages between Mg2SiO4 and Pt layers. (C) 2012 Elsevier B. V. All rights reserved.