Copper films of different thicknesses of 0.2, 0.5, 1 and 2 microns were electroplated on top of the adhesion-promoting barrier layers on <100> single crystal silicon wafers. Controlled Cu grain growth was achieved by annealing films in vacuum. The Cu film microstructure was characterized using Atomic Force Microscopy and Focused Ion Beam Microscopy. Elastic modulus of 110 to 130 GPa and hardness of 1 to 1.6 GPa were measured using the continuous stiffness option (CSM) of the Nanoindenter XP. Thicker films appeared to be softer in terms of the lower modulus and hardness, exhibiting a classical Hall-Petch relationship between the yield stress and grain size. Lower elastic modulus of thicker films is due to the higher porosity and partially due to the surface roughness. Comparison between the mechanical properties of films on the substrates obtained by nanoindentation and tensile tests of the freestanding Cu films is made.
|Original language||English (US)|
|Journal||Materials Research Society Symposium-Proceedings|
|State||Published - Jan 1 2001|
|Event||Fundamentals of Nanoindentation and Nanotribology II - Boston, MA, United States|
Duration: Nov 28 2000 → Nov 30 2000
Bibliographical noteFunding Information:
Authors would like to acknowledge support for this research from Jaynal Molla, Jin-Wook Jang and Owen Fay from Interconnect Systems Labs, Atul Konkar, Himansu Yapa, Bob Carpenter, Lester Casoose, Michael Kottke, Larry Rice and Ha Le from Process and Materials Characterization Labs and John D’urso from Physical Science Research Labs at Motorola. One of us “WWG” would like to acknowledge support from Basic Energy Sciences, Department of Energy under grant DOE-DE-FG0296ER45774.