The invention relates to a method of providing a planar substrate with electrical through connections (vias). The method comprises providing a hole in said substrate and a treatment to render the substrate surface exhibiting a lower wettability than the walls inside the hole. The planar substrate is exposed to a molten material with low resistivity, whereby the molten material is drawn into the hole(s). It also relates to a semiconductor wafer as a starting substrate for electronic packaging applications, comprising low resistivity wafer through connections having closely spaced vias.