Broadband Microwave Signal Dissipation in Nanostructured Copper Oxide at Air-Film Interface

Area of Science:

• Materials Science
• Electrical Engineering
• Spectroscopy

Background:

• Contactless broadband dielectric spectroscopy (BDS) allows for accurate *operando* analysis of electrical and magnetic properties without disrupting experimental kinetic conditions.
• BDS is sensitive to electronic structure and particularly relevant for redox reactions involving charge transfer.

Purpose of the Study:

• To study and characterize the oxidation of a copper layer within a 3-D integrated circuit (3D-IC) during cycled high-temperature storage using BDS.
• To demonstrate the utility of contactless BDS as a metrology for metal oxide-based sensing elements.

Main Methods:

• Utilized contactless broadband microwave spectroscopy (BDS) for *operando* analysis.
• Investigated copper layer oxidation in a prototypical 3D-IC under cycled high-temperature storage conditions.

Main Results:

• Microwave signal loss was attributed to energy dissipation from interactions with copper oxidation products.
• Demonstrated the sensitivity of BDS to the electronic structure changes during copper oxidation.

Conclusions:

• Contactless BDS is a viable technique for characterizing material properties during dynamic processes like oxidation.
• BDS shows potential as a metrology tool for applications utilizing metal oxides as sensing elements, particularly in integrated circuits.