  Identified charged pion, kaon, and proton spectra are used to explore the
system size dependence of bulk freeze-out properties in Cu+Cu collisions at
$\sqrt{s_{NN}}$=200 and 62.4 GeV. The data are studied with
hydrodynamically-motivated Blast-wave and statistical model frameworks in order
to characterize the freeze-out properties of the system. The dependence of
freeze-out parameters on beam energy and collision centrality is discussed.
Using the existing results from Au+Au and $pp$ collisions, the dependence of
freeze-out parameters on the system size is also explored. This
multi-dimensional systematic study furthers our understanding of the QCD phase
diagram revealing the importance of the initial geometrical overlap of the
colliding ions. The analysis of Cu+Cu collisions, which expands the system size
dependence studies from Au+Au data with detailed measurements in the smaller
system, shows that the bulk freeze-out properties of charged particles studied
here scale with the total charged particle multiplicity at mid-rapidity,
suggesting the relevance of initial state effects.
