SMOOTH SICONI ETCH FOR SILICON-CONTAINING FILMS
First Claim
1. A method of etching a silicon-containing layer on a surface of a substrate in a substrate processing region of a substrate processing chamber, wherein the method leaves a relatively smooth post-etch surface, the method comprising:
- flowing a fluorine-containing precursor and a hydrogen-containing precursor into a first remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the first plasma region to produce plasma effluents, wherein a flow rate of the fluorine-containing precursor and a flow rate of the hydrogen-containing precursor result in a hydrogen-to-fluorine atomic flow ratio of less than 1;
1 or greater than 5;
1;
etching the silicon-containing layer by flowing the plasma effluents into the substrate processing region while forming solid by-products on the surface of the substrate; and
sublimating the solid by-products to leave the relatively smooth post-etch surface by increasing a temperature of the substrate above a sublimation temperature of the solid by-products.
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Abstract
A method of etching silicon-containing material is described and includes a SiConi™ etch having a greater or lesser flow ratio of hydrogen compared to fluorine than that found in the prior art. Modifying the flow rate ratios in this way has been found to reduce roughness of the post-etch surface and to reduce the difference in etch-rate between densely and sparsely patterned areas. Alternative means of reducing post-etch surface roughness include pulsing the flows of the precursors and/or the plasma power, maintaining a relatively high substrate temperature and performing the SiConi™ in multiple steps. Each of these approaches, either alone or in combination, serve to reduce the roughness of the etched surface by limiting solid residue grain size.
300 Citations
26 Claims
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1. A method of etching a silicon-containing layer on a surface of a substrate in a substrate processing region of a substrate processing chamber, wherein the method leaves a relatively smooth post-etch surface, the method comprising:
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flowing a fluorine-containing precursor and a hydrogen-containing precursor into a first remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the first plasma region to produce plasma effluents, wherein a flow rate of the fluorine-containing precursor and a flow rate of the hydrogen-containing precursor result in a hydrogen-to-fluorine atomic flow ratio of less than 1;
1 or greater than 5;
1;etching the silicon-containing layer by flowing the plasma effluents into the substrate processing region while forming solid by-products on the surface of the substrate; and sublimating the solid by-products to leave the relatively smooth post-etch surface by increasing a temperature of the substrate above a sublimation temperature of the solid by-products. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of etching a silicon-containing layer on a surface of a substrate in a substrate processing region of a substrate processing chamber, wherein the method reduces a difference in etch-rate between a densely patterned area and a sparsely patterned area, the method comprising:
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flowing a fluorine-containing precursor and a hydrogen-containing precursor into a first remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the first plasma region to produce plasma effluents, wherein a flow rate of the fluorine-containing precursor and a flow rate of the hydrogen-containing precursor result in a hydrogen-to-fluorine atomic flow ratio of less than 1;
1 or greater than 5;
1;etching the silicon-containing layer in the densely patterned area and the sparsely patterned area by flowing the plasma effluents into the substrate processing region while forming solid by-products on the surface of the substrate; and sublimating the solid by-products by increasing a temperature of the substrate above a sublimation temperature of the solid by-products. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of etching a silicon-containing layer on a surface of a substrate in a substrate processing region of a substrate processing chamber, the method comprising:
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flowing a fluorine-containing precursor and a hydrogen-containing precursor into a first remote plasma region fluidly coupled to the substrate processing region while forming a train of plasma pulses in the first plasma region to produce plasma effluents; etching the silicon-containing layer by flowing the plasma effluents into the substrate processing region while forming solid by-products on the surface of the substrate; and sublimating the solid by-products by increasing a temperature of the substrate above a sublimation temperature of the solid by-products. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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Specification