A method for etching to form a planarized surface is disclosed. Spaced-apart features are formed of a first material, the first material either conductive or insulating. A second material is deposited over and between the first material. The second material is either insulating or conductive, opposite the conductivity of the first material. The second material is preferably self-planarizing during deposition. An unpatterned etch is performed to etch the second material and expose the top of the buried features of the first material. The etch is preferably a two-stage etch: The first stage is selective to the second material. When the second material is exposed, the etch chemistry is changed such that the etch is nonselective, etching the first material and the second material at substantially the same rate until the buried features are exposed across the wafer, producing a substantially planar surface.

 
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> Method for forming an interconnection line in a semiconductor device

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