Localized corrosion of aluminum–1.5% copper thin films exposed to photoresist developing solutions

Abstract

The extent of localized corrosion of aluminum–1.5 wt. % copper thin films during the photoresist developing process was determined using a statistically designed study. The variables studied were sublayer‐type, deposition temperature, postdeposition heat treatment, and time in rinse water. Atomic absorption spectroscopy was used to quantify the extent of localized corrosion by measuring the amount of aluminum, produced by the corrosion reaction, in the rinse water. All variables except sublayer type significantly affect localized corrosion of the Al–Cu films. The time in rinse water and developer type have the largest effects on localized corrosion. Five interaction terms are also significant. Scanning electron microscopy, Auger electron spectroscopy, and electron spectroscopy for chemical analysis were used at various steps to determine surface compositions and Cu distributions in the films. This characterization work helps explain the experimental results.