A semiconductor package comprising: a build-up carrier coupled to a die, the build-up carrier comprising a first build-up layer; and a beam element separated from a portion of the first build-up layer by an air gap, the beam element comprising a first surface and a second surface, the first surface including a plurality of edges each to define in part a respective through-hole of a plurality of through-holes which extend between the first surface and the second surface, wherein the first surface includes: a plurality of arm portions (ap) each located between a respective pair of edge-adjacent edges of the plurality of edges; and a plurality of node portions (np), wherein, for each of the node portions, two arm portions which join one another at the node portion have respective mid-lines which are oblique to one another; characterised in that the plurality of through-holes includes a first plurality of rectangular through-holes arranged in a first row along a first straight line, and a second plurality of rectangular through-holes arranged in a second row along a second straight line parallel to the first straight line, the first row adjacent to the second row, wherein sides of the edges of the first plurality of rectangular through holes and sides of the edges of the second plurality of rectangular through holes extend along respective lines of direction which are oblique to one another. a build-up carrier coupled to a die, the build-up carrier comprising a first build-up layer; and a beam element separated from a portion of the first build-up layer by an air gap, the beam element comprising a first surface and a second surface, the first surface including a plurality of edges each to define in part a respective through-hole of a plurality of through-holes which extend between the first surface and the second surface, wherein the first surface includes: a plurality of arm portions (ap) each located between a respective pair of edge-adjacent edges of the plurality of edges; and a plurality of node portions (np), wherein, for each of the node portions, two arm portions which join one another at the node portion have respective mid-lines which are oblique to one another; characterised in that the plurality of through-holes includes a first plurality of rectangular through-holes arranged in a first row along a first straight line, and a second plurality of rectangular through-holes arranged in a second row along a second straight line parallel to the first straight line, the first row adjacent to the second row, wherein sides of the edges of the first plurality of rectangular through holes and sides of the edges of the second plurality of rectangular through holes extend along respective lines of direction which are oblique to one another. a plurality of arm portions (ap) each located between a respective pair of edge-adjacent edges of the plurality of edges; and a plurality of node portions (np), wherein, for each of the node portions, two arm portions which join one another at the node portion have respective mid-lines which are oblique to one another; characterised in that the plurality of through-holes includes a first plurality of rectangular through-holes arranged in a first row along a first straight line, and a second plurality of rectangular through-holes arranged in a second row along a second straight line parallel to the first straight line, the first row adjacent to the second row, wherein sides of the edges of the first plurality of rectangular through holes and sides of the edges of the second plurality of rectangular through holes extend along respective lines of direction which are oblique to one another.