Patent ID: 8198701

Claim:
A semiconductor device comprising: a support layer; and at least one wiring level unit disposed on the support layer, each said wiring level unit comprising: a layer of thermally degradable material disposed on the support layer such that upper surface of the layer of thermally degradable material faces away from the support layer and the bottom surface of the layer of thermally degradable material faces towards the support layer; and first and second electrically conductive wiring elements disposed on the support layer and spaced apart from each other in a first direction; and a porous insulating layer disposed on the layer of thermally degradable material such that the upper surface of the porous insulating layer faces away from the layer of thermally degradable material and the bottom surface of the porous insulating layer faces towards the layer of thermally degradable material, and wherein a large space laterally adjacent to the first wiring element is constituted by a first air gap, and a portion of the thermally degradable material layer, one side of the first air gap being delimited by the first wiring element and the other side of the air gap being delimited by said portion of the thermally degradable material, a small space laterally spans the first and second wiring elements, the width of the small space as measured in the first direction being smaller than that of the large space, and at least part of the small space being constituted by a second air gap, the bottom surfaces of the first and second wiring elements are substantially coplanar with the bottom surface of the layer of thermally degradable material, and the porous insulating layer covers the first and second air gaps.