substrates assembly system has attachment areas provided with cavities

The invention concerns a device comprising a first substrate (100) with at least a bonding zone (110a, 110b), capable of being assembled with a second substrate (200), the bonding zone (110a, 110b) having a surface made of material (104) capable of being wetted by a fusible material. The invention is characterised in that the bonding zone (110a, 110b) is provided with at least one cavity (20) for receiving the fusible material.