Design, Simulation and Testing of High Density, High Current Micro-machined Embedded Capacitors

Abstract

Due to increasing speed, density and number of signal paths in integrated circuits, motivations for high density capacitors capable of quickly sourcing large amounts of current have led to many design and fabrication investigations. This work outlines continued efforts to achieve devices which meet these stringent requirements and are compatible with standard silicon fabrication processes as well as silicon interposer technologies. Previous work has been further developed resulting in devices exhibiting greater capacitance values by employing geometries which maximize surface area. The Atomic Layer Deposition (ALD) of thin layered high K materials, such as Hafnium Oxide, as opposed to previous silicon-dioxide based devices effectively increased the capacitance per unit area of the structures. This paper outlines the design, fabrication, and testing of high density micro-machined embedded capacitors capable of quickly sourcing (i.e. risetimes greater than 100A/nsec) high currents (i.e. greater than 100A). These devices were successfully simulated then tested using a standard ringdown procedure. Generally, the resulting device characterization found during testing stages strongly correlates to the expected simulated device behavior. Subsequent descriptions and design challenges encountered during fabrication, testing and integration of these passive devices are outlined, as well as potential device integration and implementation strategies for use in silicon interposers. The modification and revision of several device generations is documented and presented. Increased device capacitive density, maximized current capabilities and minimized effects of series inductance and resistance are presented. These resulting thin, capacitive structures exhibit compatibility with Si interposer technology.