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US 6,387,773 B1Granted
Method for fabricating trenches having hallows along the trenches side wall for storage capacitors of DRAM semiconductor memories
AssigneeInfineon Technologies AG
InventorManfred Engelhardt
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Abstract
A method for fabricating trenches for storage capacitors of DRAM semiconductor memories by plasma etching semiconductor substrates, includes fabricating a partial trench region with a cross-sectional profile deviating from essentially constant toward a larger cross-sectional profile. A surface of the partial trench region is passivated and the etching/passivating step is continued periodically, in order to fabricate further partial trench regions, until a predetermined overall trench depth has been reached.
Claims13
A method for fabricating trenches for storage capacitors of DRAM semiconductor memories, which comprises:
- fabricating a first partial trench region with a surface and with a cross-sectional profile deviating from an essentially constant cross-sectional profile toward a larger cross-sectional profile in a semiconductor substrate in a plasma etching step, by setting a predetermined ratio between an isotropic and an anisotropic etching component;
- passivating the surface of the first partial trench region;
- and
- continuing the etching and passivating k times periodically, where k denotes a predetermined integer, to fabricate further partial trench regions adjoining the first partial trench region in a trench course direction, until a predetermined overall trench depth has been reached.
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Dependencies are inferred from the claim text.