Overmolded semiconductor package with a wirebond cage for EMI shielding

A method for forming an electromagnetic shield for a volume above a surface of a substrate, the volume having a lateral area on, and a height above, the surface of the substrate, the substrate including a reference potential layer at or below the surface, the method comprising:

• forming a plurality of wirebonds on a substrate such that each of the wirebonds is electrically connected to the reference potential layer and has a height above the substrate, the wirebonds arranged so as to define the lateral area on the surface;
• forming an overmold that substantially occupies the lateral area and substantially encapsulates the wirebonds, the overmold having a top surface;
• and
• forming a conductive layer on the top surface of the overmold, the overmold dimensioned such that the conductive layer is at a height that is at least as high as the highest height among the wirebonds, the wirebonds dimensioned and spaced such that a combination of the wirebonds, the conductive layer and the reference potential layer provides electromagnetic shielding between interior and exterior of the volume above the surface of the substrate.