Copper Large-scale Grain Growth by UV Nanosecond Pulsed Laser Annealing

TL;DR

This paper demonstrates that UV nanosecond pulsed laser annealing can significantly enlarge copper grains in thin films, reducing resistivity while preserving surrounding structures, with potential applications in electronics manufacturing.

Contribution

It introduces UV NLA as an effective method for large-scale grain growth in copper thin films, achieving controlled grain sizes and improved electrical properties.

Findings

Mean grain size over 1 μm in melt regime

Resistivity reduction correlated with grain enlargement

Maintains structural integrity of surrounding materials

Abstract

UV nanosecond pulsed laser annealing (UV NLA) enables both surface-localized heating and short timescale high temperature processing, which can be advantageous to reduce metal line resistance by enlarging metal grains in lines or in thin films, while maintaining the integrity and performance of surrounding structures. In this work UV NLA is applied on a typical Cu thin film, demonstrating a mean grain size of over 1 {\mu}m and 400 nm in a melt and sub-melt regime, respectively. Along with such grain enlargement, film resistivity is also reduced.