Processing, Properties and Electrical Reliability of Embedded Ultra-Thin Film Ceramic Capacitors in Organic Packages

Traditional ceramic thick films have served the need for decoupling applications but require too high a temperature processing to be embedded in organic packages. Copper foil compatible sol-gel-derived ferroelectric thin film integration addresses this problem due to its unique advantages such as the ability to precisely control the composition of the films, large-area manufacturability using simple and inexpensive equipment and ease of introducing dopants to engineer the dielectric properties like loss tangent and DC leakage characteristics. This paper presents synthesis, fabrication, electrical characterization and electrical reliability test of embedded ultra thin film (200-300nm) capacitors with capacitance density >2μF/cm
²
, low-loss, low leakage current and high breakdown voltage via sol-gel technology & foil lamination. Further, we investigated the effect of (i) smoothness of the foil and (ii) non-stochiometery on the microstructure as well as on the electrical properties of sol-gel barium titanate thin films on bare copper foil. The capacitance densities, leakage characteristics and electrical reliability data demonstrate the suitability of this technology for future embedded decoupling capacitor applications.