Ceramic Thin Films for High Integration Density Capacitor Applications
- PDF / 202,903 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 22 Downloads / 199 Views
Ceramic Thin Films for High Integration Density Capacitor Applications Dan Taroata1,2, Tarik A. Cheema3, Wolf-Joachim Fischer2, Georg Garnweitner3 and Guenter Schmid1 1 Siemens AG, Corporate Technology - Global Technology Field Organic Electronics Guenter-Scharowsky-Str. 1, 91054 Erlangen, Germany 2 Technische Universität Dresden, Institute for Semiconductor and Microsystems Technology 01062 Dresden,Germany 3 Technische Universität Braunschweig, Institute of Particle Technology Volkmaroder Str. 5, 38104 Braunschweig, Germany ABSTRACT We report a novel concept for the direct integration of capacitors in printed circuit boards using ultra-small BaTiO3 and ZrO2 nanoparticles prepared by a chemical method. Electrical properties comparable to surface mount ceramic capacitors were achieved by proper processing of the nanoparticles, achieving a device-yield of >90% under research environment. The loss factor of the presented integrated capacitors does not exceed 0.05 independent of frequency, capacitor’s electrode area or applied bias voltage. INTRODUCTION The integration of passive components like capacitors, inductors and resistors into printed circuit boards (PCBs) is of high interest in the field of electronics, as these components take up to 60 % of the total area of electronic circuits [1]. Capacitors currently play the most interesting role in the field of miniaturization based on their abundance in electronic circuits, with a ratio of 3/1 for capacitors and resistors. Surface mounted (SMD) ceramic capacitors offer the possibility of a 2D placement on the surface of the upper and/or lower layer of a multi layer board. The direct processing of capacitors on a single copper layer enables a real 3D integration, by placing these components into the middle layers of multilayer PCBs. Commercially available state of the art embedded capacitors in PCBs, with a ~ 15 μm thick polymer film as dielectric layer show a very low integration density of not more than 40 pF/mm², leading to a maximum capacitance of 9 nF with a top electrode area of 225 mm². This low integration density is a result of the high thickness of the dielectric layer of 15 μm, which is required to prevent (any possible) leakage current due to the high substrate roughness of up to 5 μm. Other proposed solutions for the preparation of dielectric thin films for integrated passive applications include chemical, as well as physical vapor-based approaches [2-6]. Despite of relatively high permittivity values, as for example 140 for BaTiO3 obtained trough hydrothermal growth [7], these techniques have not reached an application for the direct integration of capacitors in printed circuit boards as they include a necessary sintering step following the synthesis at high temperatures (>600 °C), are too complex or show electric properties unsuitable for the replacement of SMD ceramic capacitors in electronic circuits (breakdown voltage within 2 V and 3 V, loss factor in the range of 0.15) [7]. Another possibility for the fabrication of dielectric layers at low temperatur
Data Loading...
