Characterization of the bending creep behavior for electroplating nickel microbeam

This study aims to investigate the creep behavior of electroplating nickel film using bending micromachined cantilever approach. The bending test including quasi-static, reloading, and time-dependent creep were performed by using a nano-indentation loading system. The resulting Young´s modulus and yielding strength were determined through mechanical testing, and the experimental average values are 191 GPa and 0.79 GPa, respectively. In addition, by measuring the load-deflection of micro cantilever under various stress levels with a constant temperature, the bending creep behavior of electroplating nickel film was determined and characterized. Experimental results show that when the bending stress is smaller than the measured yielding strength, the relation between the stress and strain rates is expressed as: (dε/dt) =0.00661n(σ) +0.0104. These test results can provide the basis for the design optimization of nickel microstructure. Thus the performance and reliability of the MEMS devices can be predicted and improved.