Patent ID: 7037851

Claim:
A method for the production of airgaps in a semiconductor device, said semiconductor device comprising a stack of layers, said stack of layers comprising at least one iteration of a sub-stack of layers, said sub-stack of layers comprising: a liner layer made of liner material; and a sacrificial layer made of sacrificial layer material under said liner layer, wherein: said liner material is resistant to a first etching substance; and said first etching substance is able to etch said sacrificial layer material; said method comprising the steps of: a) etching a hole in said stack of layers with a second etching substance; b) at least one of chemically changing and mechanically changing the properties of said liner layers locally, wherein part of said liner layers is converted locally and becomes etchable by said first etching substance, c) creating in said hole a line made of a conductive material, optionally separated from said sacrificial layer by a barrier layer, said line or, if present, said barrier layer being resistant to said first etching substance; and d) applying said first etching substance to said stack of layers, such that airgaps are created around said line.