A method for manufacturing a bulk acoustic wave resonator, each resonator including: above a substrate, a piezoelectric resonator, and next to the piezoelectric resonator, a contact pad connected to an electrode of the piezoelectric resonator; and, between the piezoelectric resonator and the substrate, a Bragg mirror including at least one conductive layer extending between the pad and the substrate and at least one upper silicon oxide layer extending between the pad and the substrate, the method including the steps of: depositing the upper silicon oxide layer; and decreasing the thickness unevenness of the upper silicon oxide layer due to the deposition method, so that this layer has a same thickness to within better than 2%, and preferably to within better than 1%, at the level of each pad.