Creep characteristics of clamped Cu membranes subjected to indentation

We present the creep characteristics of clamped Cu membranes subjected to instrumented indentation under different loads with an identical holding duration at their respective maximum loads. As-deposited Cu membranes were stored for 10 days at room temperature to release stress. During indentation, there were significant negative slopes with bouncing deflections at the holding stage because the stretched membranes relieved stress, indicating creep. Intact membranes observed under a microscope showed that such low loads are within the elastic indentation region. The critical load required to induce the presence of creep can further be classified using finite element analysis.