Provided is a formation method of a
lead frame structure. The formation method of the
lead frame structure comprises the steps that a plastic
package layer is formed, wherein the plastic
package layer is provided with a plurality of supporting areas and
cutting areas between the supporting areas, the supporting areas are internally provided with a plurality of first openings penetrating through the plastic
package layer, and the plastic package layer is provided with a first surface and a second surface opposite to the first surface; an
insulation layer is formed on the first surface of the plastic package layer, wherein the
insulation layer is internally provided with second openings exposing the first openings, the second openings are greater than the first openings in size, and the second openings further
expose part of the surface, around the first openings in the supporting areas, of the plastic package layer; the first openings and the second openings are filled with
conductive materials, and pin structures are formed in the first openings and the second openings, wherein the
insulation layer exposes the first surfaces of the pin structures, and the plastic package layer exposes the second surfaces of the pin structures. The process for forming the
lead frame is simplified, cost is lowered, and the shape and the electric connection performance of the formed lead frame structure are improved.