Patent ID: 6713396
Filing Date: 2004-03-30
Classification: B82Y,G03F,H01L

Abstract:
A method of fabricating high density sub-lithographic features, comprising:depositing a mask layer on a substrate; patterning the mask layer to define an image thereon including a minimum feature size that is greater than or equal to a minimum resolution of a lithographic system used for the patterning; etching the substrate to transfer the image to the substrate thereby defining a feature thereon, the feature including the minimum feature size, a horizontal surface positioned entirely within the substrate, and vertical side wall surfaces extending to the horizontal surface; depositing a spacer material on the horizontal and vertical side wall surfaces until the spacer material has a predetermined thickness that is less than the minimum feature size; increasing a density of features within the minimum feature size by anisotropically etching the spacer material to selectively remove the spacer material from the horizontal surfaces so that the spacer material remains on the vertical side wall surfaces and defines a plurality of sub-lithographic spacers thereon, the sub-lithographic spacers including a thickness that is less than the minimum feature size; and further increasing the density of features within the minimum feature size until a desired density of features is obtained by repeating the depositing and the anisotropically etching to define additional sub-lithographic spacers on previously defined sub-lithographic spacers, the additional sub-lithographic spacers including a thickness that is less than the minimum feature size.