Production manufacturing of PZT-based devices: Plasma etch process optimization and results for PZT used as a ferroelectric, as a High k dielectric, and as a piezoelectric material

Abstract

PZT is used in commercial microfabrication applications for three different families of devices that each rely on one of PZT¿s several useful properties, either as a ferroelectric material, as a High k dielectric material, or as a piezoelectric material. PZT, as a ferroelectric material, is widely deployed in FRAM non-volatile memory applications; PZT, as a High k material, is being used to produce integrated passive and active devices for the cell phone handset market; and PZT, as a piezoelectric material, is employed in transducer applications, such as medical ultrasound imaging. The plasma etch processes used to pattern PZT films for each of these three applications have been optimized for the given requirements of the target application. This paper covers important aspects of each of these three PZT plasma etch applications: optimizing wafer temperature during etching for fine-feature FRAM fabrication, optimizing process and tool robustness in ¿copy exactly¿ plasma etching for passive device manufacturing, and optimizing plasma etch processes for piezoelectric PZT applications with film thicknesses of tens of microns.