A major change in technology is currently underway in the microelectronics industry: the traditional aluminium-based interconnection technology is being replaced by copper. Electroplating has emerged as the method of choice for the deposition of copper metallization films because of factors such as the ability to fill trenches without voids, lower cost and better performance with regard to the phenomenon of electromigration which can lead to device failure. As a consequence of its rapid growth, the technology has in many respects outpaced the fundamental scientific understanding and many important questions need to be investigated if technological progress is to be maintained.
AFM image of electrodeposited copper metallization showing sudden morphological change during the course of the scan from top to bottom
The Advanced Metallization Science and Technology group within the Physics Department and Materials & Surface Science Institute (MSSI) at UL studies basic properties of electrodeposited copper metallization in collaboration with groups at UCC (Prof. Declan Burke) and Texas A&M University in the US (Prof. Yue Kuo) and visiting Walton Scholar Prof. Shohei Nakahara. Principal funding is from Science Foundation Ireland, with additional funding from the Irish Research Council for Science, Engineering and Technology and the Higher Education Authority.
The group in front of the MSSI building
The group provides a national resource and knowledge base for facilitating technological development and enhancing device performance and reliability, as well as providing specialized postgraduate training in this critical area of state-of-the-art microelectronics. It brings together expertise in a diverse range of areas, including film deposition, characterisation and microstructure, electrochemistry, high resolution electron microscopy, microelectronics fabrication technology, mechanical properties, electromigration, computation and modelling. Recently the group discovered
1
, using atomic force microscopy (AFM), a remarkable sudden morphological change during room temperature aging of electrodeposited copper films. This is the first such observation and opens up many other avenues of investigation. We have proposed a model based on out-diffusion of defects in the copper which explains the underlying reasons for this phenomenon.
Reference 1.
D.N. Buckley and S. Ahmed,
Electrochemical Solid State Letters,
6,
C33-C37, (2003).
Contact: Prof. D.N. Buckley, Chair of Physics, University of Limerick;
Tel. +353-61-202902; E-mail:
[email protected]
|
