The failure of interfaces between a series of styrene-butadiene random linear monodisperse polymer melts was investigated with a contact mechanics method. A thin (1 mu m) and a thick (150 mu m) film of the same polymer were deposited on a metallic cylindrical probe and on a glass slide, respectively. The two films were put in contact for up to 1000 s in a very confined geometry and the mechanical strength of interfaces formed in these conditions was then characterized by separating the probe from the glass slide. We observed different deformation micromechanisms of the layers depending on the time of contact, the debonding velocity, and the polymer used. We found that these different behaviors could be represented in a general deformation map as a function of two reduced parameters: the ratio between the contact time and the reptation time and the Deborah number. For values of DeDe(crit), two regimes were observed: for t(c)/tau(d) << 1, failure occurred by interfacial crack propagation, while for t(c)/tau(d)>= 1, an elastic cavitation mechanism followed by melt fracture was observed. For these linear polymer melts De(crit)similar to 3. (C) 2008 The Society of Rheology.