A hybrid bonding method for bonding together two semiconductor wafers, each semiconductor wafer having a plurality of mutually spaced conductive pads exposed on a top surface of the wafer and defining recesses therebetween, the method comprising the steps of: a1) depositing on a first semiconductor wafer of said semiconductor wafers, a coating layer of siloxane polymer not yet cured in a conformal manner over the top surface of said first semiconductor wafer and over its conductive pads so as to bury its conductive pads and to fill the recesses between them, said siloxane polymer being of a type that shrinks when cured; a2) realizing a second semiconductor wafer of said semiconducting wafers with exposed conductive pads and with a coating layer of either silicon oxide or of said siloxane polymer not yet cured over the top surface of said second semiconductor wafer and in the recesses between the conductive pads; b) reducing thickness of the layer of said siloxane polymer not yet cured of said first semiconductor wafer by removing a topmost portion thereof with a chemical mechanical polishing technique, so as to expose its conductive pads and to planarize them together with the recessed filled with said siloxane polymer not yet cured; c) coupling the two semiconductor wafers aligned between them one facing the other so as to place in abutment conductive pads of the two semiconductor wafers one against the other and to place in abutment one against the other said recesses filled with portions of said siloxane polymer not yet cured and/or with portions of said silicon oxide; d) placing the two semiconductor wafers together one coupled to the other in an oven with said siloxane polymer not yet cured, and baking the two semiconductor wafers together one coupled to the other at a temperature and for a time sufficient to cure at a same time the portions of said siloxane polymer and, at a same time, to make the portions of said siloxane polymer stick together or with said portions of silicon oxide. a1) depositing on a first semiconductor wafer of said semiconductor wafers, a coating layer of siloxane polymer not yet cured in a conformal manner over the top surface of said first semiconductor wafer and over its conductive pads so as to bury its conductive pads and to fill the recesses between them, said siloxane polymer being of a type that shrinks when cured; a2) realizing a second semiconductor wafer of said semiconducting wafers with exposed conductive pads and with a coating layer of either silicon oxide or of said siloxane polymer not yet cured over the top surface of said second semiconductor wafer and in the recesses between the conductive pads; b) reducing thickness of the layer of said siloxane polymer not yet cured of said first semiconductor wafer by removing a topmost portion thereof with a chemical mechanical polishing technique, so as to expose its conductive pads and to planarize them together with the recessed filled with said siloxane polymer not yet cured; c) coupling the two semiconductor wafers aligned between them one facing the other so as to place in abutment conductive pads of the two semiconductor wafers one against the other and to place in abutment one against the other said recesses filled with portions of said siloxane polymer not yet cured and/or with portions of said silicon oxide; d) placing the two semiconductor wafers together one coupled to the other in an oven with said siloxane polymer not yet cured, and baking the two semiconductor wafers together one coupled to the other at a temperature and for a time sufficient to cure at a same time the portions of said siloxane polymer and, at a same time, to make the portions of said siloxane polymer stick together or with said portions of silicon oxide.