Manufacturing process for a 3d assembly

Manufacturing process for a 3D assembly comprising the following steps:

• providing at least two assemblies, each comprising a donor substrate covered by a functional block successively comprising a first interconnection layer, a functional layer, and a second interconnection layer, the functional layer comprising one or more electronic components, the first interconnection layer and the second interconnection layer comprising a dielectric material in which are formed conductive elements, preferably made of copper, a first surface of the first interconnection layer in contact with the donor substrate and the free surface of the second interconnection layer being planarized so as to be compatible with a subsequent direct bonding,
• successively transferring, to a receiver substrate, the functional blocks, by direct bonding, the conductive elements of the first interconnection layer of the first functional block being opposite and in contact with the conductive elements of the second interconnection layer of the second functional block, whereby a 3D assembly comprising a receiver substrate covered by a stack of two functional blocks is obtained.