Process of making and using micro mask
AssigneeInternational Business Machines Corporation
InventorDonald M. Kenney
Life of this patent
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Abstract
A method is provided to enable the formation of sub-lithographic relief images to increase the surface area of semiconductor structures for use in the storage nodes of DRAM cells. The method includes the steps of forming in situ a non-planar region having a relief pattern comprising sub-micron sized elements and the transferring the relief pattern into a masking layer in order to selectively etch a substrate to form relatively deep trenches having a density equal to the relief pattern. Polysilicon and porous silicon can be used to form the sub-micron relief pattern.
Claims9
The method of forming regular sub-lithographic patterns in the range of hundreds to thousands of Angstrom units in dimension comprising the steps of:
- forming as a part of the surface of a substrate a non-planar region including a relief pattern having irregularities in its surface, the irregularities having dimensions of about 20 to 1000 Angstrom units;
- forming a masking pattern on said non-planar region using said relief pattern to determine the configuration thereof;
- and
- using the masking pattern to etch substantially vertical trench regions into said substrate.
The method of forming regular sublithographic patterns in the range of hundreds to thousands of angstrom units in dimension comprising the steps of:
- forming on the surface of a substrate a non-planar region including a relief pattern having dimensions of about 20-1000 angstrom units;
- forming a masking pattern using said relief pattern to determine the configuration thereof;
- and
- using the masking pattern to etch substantially vertical trench regions into the substrate, wherein the step of forming the masking pattern includes the step of forming a masking layer on the surface of the substrate prior to the formation of the non-planar region and wherein the formation of the non-planar region includes deposition of polycrystalline silicon.
Dependencies are inferred from the claim text.