The Effect of Nitrogen on the Formation of Nanocrystalline Copper Thin Films

Abstract

The current success of nanocrystalline materials is due to their unusual and promising properties compared to coarser grain size materials. However, maintaining the nanocrystalline character during processes or applications is not an easy task, due to the tendency towards grain growth exhibited by nanocrystalline materials. It is well known that the addition of solutes with a strong affinity for grain boundary segregation can act as pinning centers and inhibit grain growth, particularly during the manufacturing process. However, the ideal is to use these elements/compounds only during manufacturing, and after that these elements must disappear in order to attain the desirable properties. The aim of this study is to produce nanocrystalline Cu-based thin films through controlled addition of nitrogen to inhibit grain growth. A detailed chemical composition, structural and grain size analysis of these thin films was made by Electron Probe Microanalysis (EPMA), X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The results indicate that introduction of nitrogen, even in small amounts, leads to a significant decrease in grain size, particularly if Cu3N is not yielded in the thin film during the deposition process.

Understanding the Preferred Crystal Orientation of Sputtered Silver in Ar/N2 Atmosphere: A Microstructure Investigation

“…And, the Cu 3 N phase was identified with the highest P N2 : P Ar ratio of 1 : 2. Moreover, when the nitrogen content in Cu thin films was low, the grain size of Cu thin films rapidly decreased with the increase of the nitrogen content [12]. Based on all above mentioned, the N 2 content has a significant influence on the microstructures and composition of metal thin films; however, the microstructures of silver thin films prepared at various N 2 contents in Ar/N 2 atmosphere are rarely reported.…”

Nano-Nucleation Characteristic of Cu–Ag Alloy Directly Electrodeposited on W Diffusion Barrier for Microelectronic Device Interconnect

“…Selection of suitable interconnect material has become one of most important issues when fabricating ULSI systems since Cu interconnect and dual damascene structure were introduced by IBM in 1997 replacing Al interconnect. [1][2][3][4][5][6][7][8][9][10][11] Cu has higher electrical conductivity and better EM/SM resistance than Al. In addition, method to fill dual damascene features such as vias and trenches with defect-free Cu should be carefully chosen as both device node and interconnect line width get shrinking continuously.…”