Due to the enlargement of
wafer size and the increase of product integrity, thin-film stress problems
inevitably get into the range of geometric nonlinearity and are found in
multilayered thin-film materials. In this work, multilayered thin-film materials are
modeled as a large-deflection multilayered composite plate in the framework of
geometrically nonlinear plate theory. Based on the principle of virtual work for a
thin-film material plate with thin-film stresses of multiple layers as driving
forces, a nonlinear plate finite element system for kinematic fields of thin-film
materials, which includes in-plane displacements, cross section rotations,
and out-of-plane deflection, is established. The least squares method with
regularization applied for total or partial kinematic fields obtained by the
finite element method solution versus those given by experiments leads to an
iterative procedure for identification of the nonlinear multilayered thin-film
stresses.
