a via forms this hole and in some cases not only terminates a crack but can prevent the crack from initiating a via can also form an escape path for moisture stored voc 39 s and provide relief for other stress inducers overall bond strength will be directly proportional to the total surface area participating in the bond by adding vias to the leadframe additional surface area is created that may also contribute to bonding through either capillary forces surface tension other chemical mechanical means or combinations thereof the vias can u201c wick u201d attach material into the cavity and in some cases through the leadframe fig3 a is a cross section view of an alternative embodiment of the invention wherein a substrate layer 12 is provided with vias and an attached layer 14 is an ic die as will be apparent to those skilled in the arts the attach material 22 may be flowed into the vias 16 and between the layers 12 14 in order to form a 3d mechanical bond adhering the die 14 to the substrate 12 additional layers 18 may also be attached either with or without vias depending on the requirements of the specific application an encapsulant 20 typically engulfs the finished package 10 as shown in fig3 b note that as.