Aluminum-4%Copper alloys have been used as interconnect material in micro machined devices where the surface roughness was also found to play an important role in device yield. The purpose was to reduce the magnitude and intensity of the hillocks that tend to form on Aluminum alloys in similar applications. In this paper we describe observations based on manufacturing conditions using above alloy as interconnect material. It was found that the hillocks that form with above material is usually associated with a second phase precipitation. The effect of an overlayed highly compressive film was studied by laying down a multilayer silicon nitride/silicon carbide film on top of the aluminum-copper film. A further observation with this alloy was its tendency to form notches during the patterning process.

The hillocks were examined using a Dektak profilometer, and scanning electron microscopy. The Aluminum-Copper alloy films were deposited using a commercial Balzers LLS 801 sputter deposition system. The patterning was performed using a Perkin-Elmer commercial optical lithographic system followed by wet spray etching.

In this paper we give an explanation to account for the above observations.

Ferroelectric thin films enable a variety of novel electronic devices, especially when integrated with bulk or surface micromachined silicon substrates. In particular, the large piezoelectric coefficients of materials such as Pb(Zr,Ti)O₃ [PZT] are ideal for micromachined silicon actuators and force sensors. Bulk micromachined MEMS devices produced by integration of PZT thin films will be presented, as well as integration and processing strategies for ferroelectric thin films on a variety of other substrates.

Ferroelectric materials also possess high pyroelectric coefficients and are of interest for 8-14um infrared night vision applications. The development of such devices atop thermal isolation structures including aerogel films will be presented. High pyroelectric coefficents have been measured for such structures, and noise equivalent temperature difference values below 0.1 degrees C are calculated. Integration strategies, including adhesion, planarization, and stress control, will be discussed for unorthodox substrates.

Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the U.S. Department of Energy under contract DE-AC04-94A185000.