  Surface phonon-polaritons propagating along interfaces of polar dielectrics
coexist with excitons in many van der Waals heterostructures, so understanding
their mutual interactions is of great interest. Here, we investigate the type I
surface phonon polariton of hBN via low-temperature resonant-Raman spectroscopy
in hBN/WSe2 heterostructures. The resonantly enhanced hBN surface phonon
polariton (SPhP) Raman signal, when laser energy is such that the scattered
photons have energy close to that of the WSe2 excitons, enables detailed
characterization of type I SPhP in hBN even when hBN is one monolayer thick. We
find that the measured bandwidth of the SPhP Raman signal depends on the
thicknesses of the hBN layer. We are able explain the experimental data using
transfer matrix method simulations of SPhP dispersions providing that we assume
the Raman scattering to be momentum non-conserving, as could be the case if
localized WSe2 exciton states participated in the process. We further show that
resonant Raman scattering from SiO2 SPhP can also be mediated by WSe$_2$.
