AVS 65th International Symposium & Exhibition
    Advanced Surface Engineering Division Tuesday Sessions
       Session SE-TuA

Paper SE-TuA8
Scratch Behavior and Modelling of Cu/Si(100) Thin Films Deposited by Modulated Pulsed Power Magnetron Sputtering

Tuesday, October 23, 2018, 4:40 pm, Room 202C

Session: Wear, Oxidation and Corrosion Protective Coatings
Presenter: M.K. Lei, Dalian University of Technology, China
Authors: D. Meng, Dalian University of Technology, China
Y.G. Li, Dalian University of Technology, China
M.K. Lei, Dalian University of Technology, China
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A series of copper films on Si(100) substrate were deposited using modulated pulsed power magnetron sputtering under different sputtering pressure from 0.11 to 0.70 Pa. The scratch behavior of copper films on Si(100) was evaluated by scratch adhesion test with the aid of finite element modelling. With the increase of pressure, the surface morphology becomes rougher and the pattern transforms from compact fine granular structure to coarse and crack visible columnar structure, and the surface morphology of scratch tracks transforms from no obvious delamination to vast delamination. At pressure of 0.11 Pa, no obvious delamination can be observed, while copper films begin to delaminate with the growing pressure at 0.3 Pa and above at a certain load. Critical loads Lc1 to Lc4 were employed to assess the adhesion behavior of soft copper films on hard Si(100), the main exhibiting characteristics were the periodical plastic deformation on the side of scratch tip and semi-circular characteristic behind the scratch tip which were mainly caused by plastic deformation in the stick-slip process. Finite element modeling was employed to analyze the stress and strain responses of scratch on copper films by mainly using the maximum principal stress σ1 as a function of normal loads in stress concentration zone A, B and C. The location of the peak σ1 migrates from zone B to C which are tensile as the normal load increases, while peak σ1 in zone A is compressive. The directionality of σ1 for zone B tilts mostly at an out-of-plane angle mostly about 15º and 90º which may be responsible for the interface failure between the film and substrate. Critical loads Lc1 and Lc2 are evaluated through the migration of peak σ1 from zone B to C, while critical load Lc3 is associated with stress accumulation in zone C and stress accumulation in zone A is responsible for critical load Lc4. The observed plastic deformation and failure modes are able to further illustrate the physical meaning of critical loads.