Self-aligned etching method for forming high areal density patterned microelectronic structures

摘要

Within a method for forming a patterned layer there is first provided a topographic substrate. There is then formed conformally over the topographic substrate a blanket target layer formed of a target material, where the blanket target layer has a lower substantially horizontal portion, an upper substantially horizontal portion and an intermediate portion therebetween. There is then formed upon the lower substantially horizontal portion of the blanket target layer a first masking layer formed of a first masking material and formed upon the upper substantially horizontal portion of the blanket target layer a second masking layer formed of a second masking material. There is then etched, while employing an etch method having an enhanced sequential selectivity for the first masking material and the target material with respect to the second masking material, the first masking layer and the lower substantially horizontal portion of the blanket target layer to form a patterned target layer which leaves exposed a portion of the substrate beneath the lower horizontal portion of the blanket target layer while leaving unetched the upper substantially horizontal portion of the blanket target layer. The method is particularly useful for forming patterned capacitor plate layers.