Forming electrical connections for electronic devices

Abstract

A method is described for providing insulating material on an electrically conductive level (1) of a substructure (10) forming part of an electronic device, which electrically conductive level has at least two spaced-apart electrically conductive regions (1a,1b). Insulating material (2,3) is provided over the electricaly conductive level (1) to a thickness insufficient for insulating material on adjacent conductive regions (1a,1b) to meet thereby leaving a recess (4) in the insulating material between the conductive regions (1a,1b). Next a planarising medium (5) is applied onto the insulating material (2,3) and etched so as to expose a top surface (3a) of the insulating material (2,3) thereby leaving planarising medium (5a) in the recess (4). The insulating material (2,3) is then etched anisotropically using the remaining planarising medium (5a,5b) as a mask so that the surface (11) of the electrically condutive level (1) is exposed. The etching of the insulating material ( 2,3) is controlled so that the insulating material is etched away just down to the bottom (50a) of the planarising medium (5a) in the recess (4) and the remaining planarising medium (5a,5b) is then removed so as to leave the surface of the substructure (10) between the electrically conductive regions (1a,1b) covered by a relatively flat layer (30) of insulating material. A further layer (6), for example of insulating mateirl, is then deposited onto the remaining relatively flat layer of insulating material.