Conductive pads of a flex circuit may be electrically connected to conductive pads of a rigid circuit board. The conductive pads of the flex circuit may be sized, configured and alignable to the conductive pads of the rigid circuit board. A spacer with a plurality of apertures may be sized, configured and aligned to the conductive pads of the flex circuit and the rigid circuit board. Solder paste may be disposed between respective conductive pads of the flex circuit and the rigid circuit board within the apertures of the spacer. When the flex circuit, rigid circuit board and the spacer are assembled, the solder paste is displaced through relief vents formed through the conductive pads of the flex circuit, rigid circuit board or both the flex circuit or rigid circuit board. The solder paste is reflowed and forms a rivet structure attaching the flex circuit to the rigid circuit board as well as providing an electrical connection between the conductive pads of the flex circuit and the rigid circuit board.