Abstract: An adapter for retaining a wafer has a back side intended to be placed on, and to extend over, a first suction channel and a second suction channel disposed on a main face of a support. The adapter has a shallow recess disposed on the front side to receive the wafer, the shallow recess being shaped to the wafer size and having a flat base to contact a surface of the wafer. The adapter also includes a vacuum network extending through the adapter and comprising at least one through-passage connecting the adapter back side and the adapter front side, the through-passage opening out, on the front side, in the shallow recess. The through-passage intercepts, on the back side, the first suction channel of the support but not the second suction channel.