Patent ID: 8383515
Filing Date: 2013-02-26
Classification: H01L

Abstract:
1. A method of forming a wordline, comprising steps of: (a) providing a plurality of trenches with a plurality of first polycrystalline (POLY) cells, each of which is deposited between two neighboring ones of the plurality of trenches; (b) depositing a first fill-in material comprising an oxide material with a first etching rate in the plurality of trenches; (c) etching back a portion of the first fill-in material in each of the plurality of trenches to form a liner layer of the oxide material deposited on each side wall of the plurality of first POLY cells; (d) depositing a second fill-in material with a second etching rate upon the liner layer and the plurality of first POLY cells; (e) depositing a second POLY layer upon the second fill-in material; (f) etching back a portion of the second POLY layer to form the wordline with a residual of the second POLY layer formed on an exposed portion of the second fill-in material; and (g) removing the residual of the second POLY layer, the exposed portion of the second fill-in material, and the liner layer under the exposed portion of the second fill-in material.