We present a mixed-integer programming (MIP) approach to compute aircraft arrival routes in a terminal maneuvering area (TMA) that guarantee temporal separation of all aircraft arriving within a given time period, where the aircraft are flying according to the optimal continuous descent operation (CDO) speed profile with idle thrust. The arrival routes form a merge tree that satisfies several operational constraints, e.g., all merge points are spatially separated. We detail how the CDO speed profiles for different route lengths are computed. Experimental results are presented for calculation of fully automated CDO-enabled arrival routes during one hour of operation on a busy day at Stockholm TMA.