Geraldine Cogin Schwartz

Reactive ion etching induced corrosion of Al and Al‐Cu films

Aluminum and Al‐Cu conductor lines etched with a Cl containing plasma in low‐pressure diode systems corroded rapidly upon atmospheric exposure. The mechanisms underlying this corrosion problem were investigated using Auger electron and x‐ray photoelectron spectroscopies. Reactive ion etching resulted in a nonprotective oxide layer and thus rendered the etched samples more susceptible to atmospheric corrosion. Factors contributing to the increased reactivity of etched samples includes C and Cl contamination, radiation damage, and for Al‐Cu alloys, Cu enrichment. A thermal oxidation treatment at temperatures of ∼300–350 °C and l atm O2 pressure for ≳30–45 min was found to be effective in restoring the protective oxide layer and thus improving the corrosion resistance of etched samples.

Plasma‐Enhanced Chemical Vapor Deposition of Silicon Dioxide Films Using Tetraethoxysilane and Oxygen: Characterization and Properties of Films

SiO 2 films were deposited in a commercial single wafer parallel plate plasma deposition reactor using tetraethoxysilane as the silicon source. Deposition conditions were varied to produce films with widely differing properties. Electrical, optical, mechanical, and wet-etch-rate characterization were then used to investigate the as-deposited film quality. Moisture uptake was also measured and related to the initial properties. The films were studied in an ongoing investigation of silicon dioxide interlevel dielectric films used in multilevel ultra large scale integrated chip wiring

Corrosion and protection of thin-line conductors in VLSI structures

Thin metallic lines in VLSI circuit structures are usually encapsulated in a dielectric in order to protect them from the atmosphere and prevent corrosion. However, during processing the lines are unprotected. Some of the steps to which they are subjected during processing are quite aggressive and can result in a significant yield loss. This paper pertains to the loss which is due to corrosion during processing. It focuses on the corrosion behavior of the two of the most commonly used conductors, aluminum and copper. Aluminum alloyed with small amounts of copper is also considered. The corrosion-related behaviors of aluminum and copper are vastly different, as is shown by their reaction with water and several processing solutions. The challenge of minimizing corrosion during processing as well as during subsequent storage and use is discussed, using suitable examples drawn from studies of thin films of the metals exposed to chemical etching, reactive ion etching, and cleaning.