a central part can be envisioned as providing extreme anchoring capabilities fig2 d shows a top view of anchor 26 of fig2 a more clearly highlighting the location of the anchor 26 of mold compound with respect to both the substrate 22 and the applied mold cap 24 the anchor 26 extends out as shown in fig2 b parallel to the plane of the substrate 22 from the body of the mold compound over the semiconductor device the mold cap 24 to the opening 28 this assures that the mold compound of the anchor 26 penetrates perpendicular to the plane of the substrate 22 into the opening 28 created through the substrate 22 with the basic concept of the invention in mind that is providing an anchor that forms a solid interconnection between the supporting substrate and the overlying mold cap it is clear that a number of variations of this concept can be used some of these variations are highlighted using fig3 a through 3 d for this purpose referring first specifically to the cross section that is shown in fig3 a there is shown a cross section 32 of a top cavity bar a cross section 30 of a bottom cavity bar a substrate 34 with copper interconnect traces 35 provided over the surface thereof anchor opening 37 has been provided through each of the four corners of substrate 34 by modifying the contours of the top and bottom cavity bars 32 30 where these cavity bars are aligned with the anchor opening 37 the contours of the applied mold compound can be controlled in the example that is shown in the cross section of fig3 a a top cavity relief 36 has been indicated that extends over a distance of substrate 34 allowing additional.