Title :
BCB with nano-filled BaSrTiO3 for thin film capacitors
Author :
Töpper, Michael ; Fischer, Thorsten ; Zang, Marcus ; Teipel, Ulrich ; Fehrenbacher, Ulrich ; Reichl, Herbert
Author_Institution :
Fraunhofer IZM, Berlin
Abstract :
A BaSrTiO3-BCB composite was developed for spin-coating to integrate capacitors into multilayer wiring for Wafer Level Packaging (WLP) and System in Package (SiP). The size of nanoscale barium strontium titanate crystallite size was measured as 24 nm. The matrix for the composite was BCB with 63 wt.-% solids dissolved in mesitylene. Various dispersants were tested to find the best surfactant for the stabilization of BaSrTiO3 in mesitylene, which is compatible with BCB. The optimum dispersant was used for preparation of suspensions with a solid loading of 20 - 35 wt.-% BaSrTiO3 dispersed in mesitylene using 5.0 - 10 wt.-% dispersant. The resulting average layer thickness of the cured composite is in the range of 1.7 mum. These films can be easily integrated into existing thin film multilayer built-up wiring structures. The relative dielectric constant epsivr of the investigated BaSrTiO3-BCB composite is 31. The breakdown voltage of the exceeds 170 V for 1.7 mum thickness which equals a dielectric strength of 1.0 MV/cm. High reliability was proven for humidity storage (85degC and 85% rel. humidity, 2000 hrs) and thermal cycling from (AATC from -55degC to +125degC, 2000 cycles).
Keywords :
barium compounds; electric breakdown; humidity; multilayers; nanoelectronics; nanostructured materials; organic compounds; permittivity; strontium compounds; system-in-package; thermal management (packaging); thin film capacitors; wafer level packaging; BCB composite; BaSrTiO3; benzocyclobutene; breakdown voltage; dielectric strength; dispersant; humidity storage; mesitylene; multilayer wiring; nanoscale barium strontium titanate crystallite size; optimum dispersant; relative dielectric constant; size 1.7 mum; size 24 nm; spin coating; surfactant; suspensions preparation; system in package; temperature -55 C to 125 C; thermal cycling; thin film capacitor integration; thin film multilayer built-up wiring structure; time 2000 h; voltage 170 V; wafer level packaging; Barium; Capacitors; Dielectric thin films; Humidity; Nonhomogeneous media; Packaging; Solids; Strontium; Wafer scale integration; Wiring;
Conference_Titel :
Electronic Components and Technology Conference, 2009. ECTC 2009. 59th
Conference_Location :
San Diego, CA
Print_ISBN :
978-1-4244-4475-5
Electronic_ISBN :
0569-5503
DOI :
10.1109/ECTC.2009.5074101