  A combination of out-of-plane and in-plane magnetoconductance (MC) study in
topological insulators (TI) is often used as an experimental technique to probe
weak anti-localization (WAL) response of the topological surface states (TSSs).
However, in addition to the above WAL response, weak localization (WL)
contribution from conducting bulk states are also known to coexist and
contribute to the overall MC; a study that has so far received limited
attention. In this article, we accurately extract the above WL contribution by
systematically analyzing the temperature and magnetic field dependency of
conductivity in Bi$_2$Se$_3$ films. For accurate analysis, we quantify the
contribution of electron-electron interactions to the measured MC which is
often ignored in recent WAL studies. Moreover, we show that the WAL effect
arising from the TSSs with finite penetration depth, for out-of-plane and
in-plane magnetic field can together explain the anisotropic magnetoconductance
(AMC) and, thus, the investigated AMC study can serve as a useful technique to
probe the parameters like phase coherence length and penetration depth that
characterise the TSSs in 3D TIs. We also demonstrate that increase in
bulk-disorder, achieved by growing the films on amorphous SiO$_2$ substrate
rather than on crystalline Al$_2$O$_3$(0001), can lead to stronger decoupling
between the top and bottom surface states of the film.
