Method of plasma etching of silicon carbide
First Claim
1. A method of plasma etching a layer of silicon carbide with selectivity to underlying and overlying low-k layers of dielectric material, the method comprising:
- positioning a semiconductor substrate in a reactor chamber, the substrate including a layer of silicon carbide and underlying and overlying layers of low-k dielectric material;
supplying an etchant gas to the chamber, the etchant gas comprising at least one hydrogen-containing fluorocarbon gas, an oxygen containing gas, and optional carrier gas; and
energizing the etchant gas into a plasma state and forming etched openings in the silicon carbide layer, the etched openings being defined by openings in the overlying layer of low-k dielectric material and the etched openings being over the underlying layer of low-k dielectric material, the silicon carbide layer being etched at a faster rate than the underlying and overlying layers of low-k dielectric material.
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Abstract
The invention provides a process for plasma etching silicon carbide with selectivity to an overlapping and/or underlying dielectric layer of material. The etching gas includes a hydrogen-containing fluorocarbon gas such as CH3F, an oxygen-containing gas such as O2 and an optional carrier gas such as Ar. The dielectric material can comprise silicon dioxide, silicon nitride, silicon oxynitride or various low-k dielectric materials including organic low-k materials. In order to achieve a desired selectivity to such dielectric materials, the plasma etch gas chemistry is selected to achieve a desired etch rate of the silicon carbide while etching the dielectric material at a slower rate. The process can be used to selectively etch a hydrogenated silicon carbide etch stop layer or silicon carbide substrates.
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Citations
22 Claims
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1. A method of plasma etching a layer of silicon carbide with selectivity to underlying and overlying low-k layers of dielectric material, the method comprising:
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positioning a semiconductor substrate in a reactor chamber, the substrate including a layer of silicon carbide and underlying and overlying layers of low-k dielectric material;
supplying an etchant gas to the chamber, the etchant gas comprising at least one hydrogen-containing fluorocarbon gas, an oxygen containing gas, and optional carrier gas; and
energizing the etchant gas into a plasma state and forming etched openings in the silicon carbide layer, the etched openings being defined by openings in the overlying layer of low-k dielectric material and the etched openings being over the underlying layer of low-k dielectric material, the silicon carbide layer being etched at a faster rate than the underlying and overlying layers of low-k dielectric material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 16, 17, 18, 19, 20, 21)
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13. A method of plasma etching a layer of silicon carbide with selectivity to an overlying layer of low-k dielectric material, the method comprising:
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positioning a semiconductor substrate in a reactor chamber, the substrate including a layer of silicon carbide and an overlying layer of low-k dielectric material;
supplying an etchant gas to the chamber, the etchant gas comprising at least one hydrogen-containing fluorocarbon gas, an oxygen containing gas, and optional carrier gas; and
energizing the etchant gas into a plasma state and forming etched openings in the silicon carbide layer, the etched openings being defined by openings in the overlying layer of low-k dielectric material, the silicon carbide layer being etched at a faster rate than the overlying layer of low-k dielectric material, wherein the substrate includes a patterned silicon dioxide hard mask above the layer of low-k dielectric material, the layer of low-k dielectric material having been previously etched to expose the silicon carbide layer at locations corresponding to openings in the hard mask, the silicon carbide being etched with an etch rate selectivity to the hard mask of at least 5. - View Dependent Claims (14)
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22. A method of plasma etching a layer of silicon carbide with selectivity to underlying and overlying low-k layers of dielectric material, the method comprising:
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positioning a semiconductor substrate in a reactor chamber, the substrate including a layer of silicon carbide, and underlying and overlying layers of low-k dielectric material, the low-k dielectric material having a dielectric constant of less than 3.0;
supplying an etchant gas to the chamber, the etchant gas comprising at least one hydrogen-containing fluorocarbon gas, an oxygen containing gas, and optional carrier gas; and
energizing the etchant gas into a plasma state and forming etched openings in the silicon carbide layer, the etched openings being defined by openings in the overlying layer of low-k dielectric material and the etched openings being over the underlying layer of low-k dielectric material, the silicon carbide layer being etched at a faster rate than the underlying and overlying layers of low-k dielectric material.
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Specification