Interlocking via for package via integrity

A method of forming an interconnection structure in a microelectronic package, and an interconnection structure of a microelectronic package formed according to the method. The method includes: providing a combination including a first conductive layer and a dielectric layer fixed to the conductive layer; providing a hole through the dielectric layer extending from a surface of the dielectric layer to the first conductive layer; providing a recess in the first conductive layer and in communication with the hole to provide an interlocking volume under the dielectric layer; providing a conductive material in the hole and in the recess to form a package via having an interlocking section in the interlocking volume of the recess; and providing a conductive material on the dielectric layer to form a second conductive layer adapted to be in electrical contact with the first conductive layer through the package via.