Method of improving micro-loading effect when recess etching tungsten layer
AssigneesUnited Microelectronics Corp., Fujian Jinhua Integrated Circuit Co., Ltd.
InventorsLi-Chiang Chen, Fu-Che Lee, Ming-Feng Kuo
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Abstract
A method of improving micro-loading effect when recess etching a tungsten layer. A substrate having trenches thereon is provided. A tungsten layer is deposited on the substrate and in the trenches. A planarization process is performed to form a planarization layer on the tungsten layer. A first etching process is performed to etch the planarization layer and the tungsten layer with an etch selectivity of planarization layer:tungsten layer=1:1 until the planarization layer is completely removed. A second etching process is performed to etch the remainder of the tungsten layer to recess the tungsten layer within the trenches.
Claims7
A method for improving micro-loading effect when recess etching a tungsten layer, comprising:
- providing a semiconductor substrate having a main surface, wherein a plurality of trenches is formed in the semiconductor substrate;
- blanket depositing a tungsten layer on the semiconductor substrate, wherein the plurality of trenches is filled with the tungsten layer;
- subjecting the tungsten layer to a planarization process to form a planarization layer on the tungsten layer;
- performing a first etching process to completely remove the planarization layer and partially remove the tungsten layer with an etch selectivity of planarization layer:tungsten layer=1:1;
- and
- performing a second etching process to etch remainder of the tungsten layer until a top surface of the tungsten layer is lower than the main surface of the semiconductor substrate.
Dependencies are inferred from the claim text.