Method forming via hole that utilizes lazer drill

A method for forming a via hole using a laser drill is provided to reduce plating defects through uniformization of the shape of hole by previously removing a glass fiber of prepreg with a mechanical drill and forming the via hole in a resin filled in a part where the glass fiber is removed by the laser drill. A method for forming a via hole using a laser drill includes the steps of: preparing a first circuit substrate(200) having circuits(202) on both surfaces of an insulation layer(201); preparing a plurality of prepregs(210) having via hole points punched through mechanical drilling; stacking the prepregs(210) on both surfaces where the circuits(202) of the first substrate(200) are formed; and fabricating the via hole with a laser drill at the via hole points filled with resin by flowing down the resin of the prepregs(210) at the above step.