  We study the relation between the boxed skew plane partition and the
integrable phase model. We introduce a generalization of a scalar product of
the phase model and calculate it in two ways; the first one in terms of the
skew Schur functions, and another one by use of the commutation relations of
operators. In both cases, a generalized scalar product is expressed as a
determinant. We show that a special choice of the spectral parameters of a
generalized scalar product gives the generating function of the boxed skew
plane partition.
