A semiconductor device and a fabrication method thereof are disclosed. The method includes attaching a wafer with a plurality of chips on a carrier board having an insulating layer, a plurality of conductive circuits and a bottom board; forming a plurality of first grooves between solder pads of adjacent chips to expose the conductive circuits, and filling the first grooves with an insulating adhesive layer; forming second grooves in the insulating adhesive layer; and cutting among the chips to separate the chips from one another.