  Angle-resolved photoemission spectroscopy using tunable low energy photons
allows us to study the quasi-particle (QP) dispersions of the inner and outer
CuO2 planes (IP and OP) separately in the tri-layer cuprate
Bi$_2$Sr$_2$Ca$_2$Cu$_3$O$_{10+\delta}$ (Bi2223). The kink energy of the OP
band is $\sim$ 70 meV, as observed in various high-$T_c$ cuprates, while that
of the IP band is as large as 100 meV in the superconducting (SC) state. This
large kink energy is attributed to the $\sim$ 35 meV buckling mode plus the
large ($\sim$ 60 meV) SC gap of IP. The IP band also shows a weak kink feature
at 70 meV in the SC state. The latter feature can be explained either by the 70
meV half-breathing mode or by the $\sim$ 35 meV buckling-phonon mode plus the
$\sim$ 40 meV SC gap of OP if interlayer scattering of QP is involved.
