Method for etching tungsten using NF3 and Cl2
First Claim
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1. A method of anisotropically etching a layer containing tungsten, the layer being disposed on a substrate and having a patterned hard mask layer disposed thereon, the method comprising:
- placing the substrate in a plasma zone;
introducing into the plasma zone a process gas mix comprising NF3 and Cl2; and
forming a plasma from the process gas mix to etch the tungsten containing layer substantially anisotropically and at an etch rate greater than the rate at which the hard mask layer is etched.
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Abstract
A method for etch a tungsten-containing layer (525) on a substrate (510) substantially anisotropically with good etching selectivity with respect to a hard mask layer, and without forming excessive passivating deposits on the etched features. In the method, the substrate (510) is placed in a plasma zone, and process gas mix comprising NF3 and Cl2is introduced into the plasma zone. A plasma is formed from the process gas mix to anisotropically etch the tungsten containing layer (525) to produce patterned tungsten features (535).
27 Citations
21 Claims
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1. A method of anisotropically etching a layer containing tungsten, the layer being disposed on a substrate and having a patterned hard mask layer disposed thereon, the method comprising:
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placing the substrate in a plasma zone;
introducing into the plasma zone a process gas mix comprising NF3 and Cl2; and
forming a plasma from the process gas mix to etch the tungsten containing layer substantially anisotropically and at an etch rate greater than the rate at which the hard mask layer is etched. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of etching a tungsten containing layer that is covered with a patterned hard mask layer and disposed on a substrate, using a process chamber that has process electrodes therein and an inductor coil adjacent to the process chamber, the method comprising:
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placing the substrate on which the tungsten containing layer is disposed into the process chamber;
introducing into the process chamber, a process gas mix comprising NF3 and Cl2; and
ionizing the process gas mix to form plasma ions that energetically impinge on the tungsten containing layer and the hard mask layer by applying RF energy to the inductor coil and applying RF energy the process electrodes, wherein the tungsten containing layer is substantially anisotropically etched at an etch rate greater than the rate at which the hard mask layer is etched. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of etching a tungsten containing layer that is covered with a patterned hard mask layer and disposed on a substrate, using a process chamber that has process electrodes therein and an inductor coil adjacent to the process chamber, the method comprising:
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placing the substrate on which the tungsten containing layer is disposed into the process chamber;
introducing into the process chamber, a main etch process gas mix comprising NF3 and Cl2;
ionizing the main etch process gas mix to form plasma ions that energetically impinge on the tungsten containing layer and the hard mask layer by applying RF energy to the inductor coil and applying RF energy the process electrodes, wherein the tungsten containing layer is substantially anisotropically etched at a main etch rate greater than the rate at which the hard mask layer is etched;
introducing into the process chamber, an over etch process gas mix comprising Ar and Cl2; and
ionizing the over etch process gas mix to form plasma ions that energetically impinge on the tungsten containing layer and the hard mask layer by applying RF energy to the inductor coil and applying RF energy the process electrodes, wherein any remaining portion of the tungsten containing layer that is not masked by the hard mask layer is substantially anisotropically etched away. - View Dependent Claims (20, 21)
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Specification