Abstract: A new method is provided for the creation of a dual damascene structure. The method of the invention uses a gray tone mask to form dual damascene trenches in one single masking and etch step. The gray tone mask technology allows for a photoresist patterning process after which the photoresist profile can be transferred into the underlying substrate by an etch process. By making the photoresist profile equal to the profile of a dual damascene structure, the dual damascene profile can be created in the surface of a substrate.

Abstract: Hybrid alignment markings with a plurality of parallel marks on an active area of a silicon layer on which a multilayer structure are formed by forming initial marks in the active area by modifying the profile of the active area producing an active area surface of the active area with initial marks and then forming on the active area surface a set of interleaved marks from a second, polysilicon layer to form a single composite alignment marking composed of the initial marks and the interleaved marks. One technique is to form shallow steps with shallow trenches with low mesas in the silicon layer followed by forming low ribs of the second, polysilicon layer on the low mesas adjacent interleaved with the shallow trenches. Alternatively, form shallow cavities with low ribs in the silicon layer forming exposed low cavity surfaces of the silicon layer, and then form additional low ribs of a polysilicon layer in the shallow cavities on the exposed low cavity surfaces of the silicon layer.

Abstract: Under the first embodiment of the invention, a three layer composite layer of insulation is deposited. The trench is etched into this composite layer of insulation followed by a hard bake. The via etch is performed, completing the formation of the dual damascene profile. The created dual damascene profile is transferred into the underlying substrate; the layer of photoresist is removed. Under the second embodiment of the invention, a two layer composite layer of insulation is deposited over a semiconductor surface. The trench is etched into this composite layer of insulation. A layer of positive photoresist is deposited over the second layer of cross-linked negative resist and masked for the via etch. The via etch is performed, the created dual damascene profile is transferred into the underlying substrate. The removal of the layers of patterned photoresist completes the formation of the dual damascene structure.