FOCUS RING, PLASMA ETCHING APPARATUS AND PLASMA ETCHING METHOD
First Claim
1. A focus ring for use in a plasma etching apparatus for performing an etching by using a plasma on a surface of a substrate mounted on a susceptor in an airtight processing vessel, the focus ring being provided to surround a periphery of the substrate, comprising:
- a lower step portion formed at an inner peripheral side of the focus ring; and
an upper step portion surrounding the lower step portion,wherein a top surface of the upper step portion is divided into a first region at an inner side on the top surface of the upper step portion and a second region surrounding the first region, andwherein an average surface roughness Ra of the first region is small such that a reaction product produced during an etching processing is not captured to be deposited on a corresponding region and an average surface roughness Ra of the second region is large such that a reaction product is captured to be deposited on a corresponding region.
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Abstract
In a plasma etching apparatus for performing a plasma etching on a surface of a substrate mounted on a susceptor in a processing vessel, a focus ring is installed to surround the substrate and has a first region at an inner side on a surface thereof, in which an average surface roughness is small such that a reaction product produced during an etching processing is not captured to be deposited, and a second region at an outer side from the first region, in which an average surface roughness is large such that a reaction product produced during the etching process is captured to be deposited. A boundary between the first and the second region is a part where an etching amount is relatively significantly changed compared to other parts while the focus ring is equipped in the plasma etching apparatus and the plasma etching is performed on the substrate.
220 Citations
16 Claims
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1. A focus ring for use in a plasma etching apparatus for performing an etching by using a plasma on a surface of a substrate mounted on a susceptor in an airtight processing vessel, the focus ring being provided to surround a periphery of the substrate, comprising:
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a lower step portion formed at an inner peripheral side of the focus ring; and an upper step portion surrounding the lower step portion, wherein a top surface of the upper step portion is divided into a first region at an inner side on the top surface of the upper step portion and a second region surrounding the first region, and wherein an average surface roughness Ra of the first region is small such that a reaction product produced during an etching processing is not captured to be deposited on a corresponding region and an average surface roughness Ra of the second region is large such that a reaction product is captured to be deposited on a corresponding region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 15)
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9. A focus ring for use in a plasma etching apparatus for performing an etching by using a plasma on a surface of a substrate mounted on a susceptor in an airtight processing vessel, the focus ring being provided to surround a periphery of the substrate, comprising:
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a lower step portion formed at an inner peripheral side of the focus ring; and an upper step portion surrounding the lower step portion, wherein a top surface of the upper step portion is divided into a first region having a first average surface roughness at an inner side on the top surface of the upper step portion; and
a second region having a second average surface roughness, which is greater than the first average surface roughness, surrounding the first region. - View Dependent Claims (10, 11, 12, 13, 14)
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16. The plasma etching method, wherein a silicon layer is etched by a gaseous mixture of an oxygen gas and an etching gas containing a halogen.
Specification