A process for assembly of an integrated device, envisages: providing a first body of semiconductor material integrating at least one electronic circuit and having a top surface; providing a second body of semiconductor material integrating at least one microelectromechanical structure and having a bottom surface; and stacking the second body on the first body with the interposition, between the top surface of the first body and the bottom surface of the second body, of an elastic spacer material. Prior to the stacking step, the step is envisaged of providing, in an integrated manner, at the top surface of the first body a confinement and spacing structure that confines inside it the elastic spacer material and supports the second body at a distance from the first body during the stacking step.