HIGH ASPECT RATIO 3-D FLASH MEMORY DEVICE

摘要

Methods of selectively etching tungsten from the surface of a patterned substrate are described. The etch electrically separates vertically arranged tungsten slabs from one another as needed, for example, in the manufacture of vertical flash memory devices. The tungsten etch may selectively remove tungsten relative to films such as silicon, polysilicon, silicon oxide, aluminum oxide, titanium nitride and silicon nitride. The methods include exposing electrically-shorted tungsten slabs to remotely-excited fluorine formed in a capacitively-excited chamber plasma region. The methods then include exposing the tungsten slabs to remotely-excited fluorine formed in an inductively-excited remote plasma system. A low electron temperature is maintained in the substrate processing region during each operation to achieve high etch selectivity.

主权项

1. A 3-D flash memory device comprising:
a plurality of electrically-isolated tungsten slabs arranged in two adjacent vertical columns, wherein the plurality of electrically-isolated tungsten slabs comprise at least fifty tungsten slabs in the two adjacent vertical columns; a plurality of dielectric slabs interleaved with the plurality of electrically-isolated tungsten slabs, wherein at least fifty of the plurality of electrically-isolated tungsten slabs are recessed between 1 nm and 7 nm laterally relative to the plurality of dielectric slabs.