Influence of Mixed Acid Electrolytes and Rare Earth Additives on the Corrosion Resistance of Anodized Aluminum Films

Document Type

Student Presentation

Presentation Date


Faculty Sponsor

Chad Watson


Over the last ten years, the average pitch size between interconnects in semiconductor devices has decreased from 60 nm to under 16 nm. To enable smaller pitch sizes, materials with less resistance, such as copper compared to aluminum, are used in the contact layers. The new materials require higher voltages and more corrosive chemicals during dry etch and chemical-mechanical-planarization processing. This caustic environment decreases the average lifetime of anodized components that are used in the processing chambers. NxEdge, an ISO 9001:2000 certified manufacturing and coating company located in Boise, ID, is interested in investigating methods to create more robust anodized components. For this project, a multiphase design was implemented to study the influence of mixed acid electrolytes, rare earth salts, anodizing temperature, and current density settings on the quality of anodized films. Following NxEdge’s qualification assurance process, breakdown voltage and accelerated acid corrosion tests were performed to evaluate film quality. Aluminum that was anodized using a sulfuric/boric mixed acid electrolyte at higher temperature and lower current density settings exhibited an increased breakdown voltage by approximately1.6X over the standard process. The acid corrosion test was improved by more than 380X over the standard and more than 28X over the project goal.

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