Abstract: In the present invention a dummy structure is formed in a first deposited layer in order to create topography, generally a raised area, in a deposited layer formed above and later than the first deposited layer. This topography may be advantageous in later steps. In one embodiment, transferred topography allows an alignment or overlay mark obscured by an opaque layer to be located by this enhanced topography. In another embodiment, a raised volume of dielectric material prevents features at the outside of an array area from being overpolished during a CMP step. This method may prove useful in other contexts as well. The size, shape, and placement of the dummy structure is tailored to form the desired excess volume.

Abstract: A memory cell is described suitable for use in a high-density monolithic three dimensional memory array. In preferred embodiments of the memory cell, a semiconductor junction diode formed of germanium or a germanium alloy which can be crystallized at relatively low temperature is formed disposed between conductors. The use of a low-temperature material allows the conductors to be formed of copper or aluminum, both low-resistivity materials that provide adequate current at very small feature size, allowing for a highly dense stacked array.

Abstract: A substantially planar surface coexposes conductive or semiconductor features and a dielectric etch stop material. A second dielectric material, different from the dielectric etch stop material, is deposited on the substantially planar surface. A selective etch etches a hole or trench in the second dielectric material, so that the etch stops on the conductive or semiconductor feature and the dielectric etch stop material. In a preferred embodiment the substantially planar surface is formed by filling gaps between the conductive or semiconductor features with a first dielectric such as oxide, recessing the oxide, filling with a second dielectric such as nitride, then planarizing to coexpose the nitride and the conductive or semiconductor features.

Abstract: A method is provided to clean slurry particles from a surface in which tungsten and dielectric are coexposed after a dielectric CMP step. Such a surface is formed when tungsten features are patterned and etched, the tungsten features are covered with dielectric, and the dielectric is planarized to expose tops of the tungsten features. The surface to be cleaned is subjected to mechanical action in an acid environment. Suitable mechanical action includes performing a brief tungsten CMP step on the tungsten features or scrubbing the surface using, for example, a commercial post-CMP scrubber.

Abstract: When chemical mechanical planarization (CMP) is used to planarize a surface coexposing patterned features and dielectric fill, where patterned features and the fill are formed of materials having very different CMP removal rates or characteristics, the planarized surface may have excessively rough, dishing or recessing may take place, or one or more or the materials may be damaged. In structures in which planarity is important, these problems can be prevented by forming a capping layer on the patterned features, wherein the CMP removal rate of the material forming the capping layer is similar to the CMP removal rate of the dielectric fill.

Abstract: 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.