US20220270863A1

US20220270863A1 - Moveable edge rings with reduced capacitance variation for substrate processing systems

Info

Publication number: US20220270863A1
Application number: US17/671,211
Authority: US
Inventors: Christopher Kimball; Hema Swaroop Mopidevi; Saravanapriyan Sriraman; Tom A. Kamp; Darrell Ehrlich; Anthony Contreras; Chiara Helena Catherina Giammanco Macpherson
Original assignee: Lam Research Corp
Current assignee: Lam Research Corp
Priority date: 2019-08-05
Filing date: 2022-02-14
Publication date: 2022-08-25
Also published as: KR20220035979A; TW202121484A; TWM602283U; KR102646633B1; JP2022163709A; US20220254612A1; JP2022544102A; WO2021026110A1; KR20220037522A; EP4036955A1; CN114207769A; KR20240034892A; EP4010918A1; KR20230155028A; CN114695062A; KR20230156438A; EP4010918A4; CN212874424U; JP7553544B2

Abstract

A moveable edge ring system for a plasma processing system includes a top edge ring and a first edge ring arranged below the top edge ring. A second edge ring is made of conductive material and includes an upper portion, a middle portion and a lower portion. The top edge ring and the second edge ring are configured to move in a vertical direction relative to a substrate support and the first edge ring when biased upwardly by a lift pin. The second edge ring is arranged below the top edge ring and radially outside of the first edge ring.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure is a of U.S. patent application Ser. No. 17/632,066, filed on Feb. 1, 2022, which is a National Stage of International Application No. PCT/US20/44816, filed on Aug. 4, 2020, claiming the benefit of U.S. Provisional Application No. 62/976,088, filed on Feb. 13, 2020, and U.S. Provisional Application No. 62/882,890, filed Aug. 5, 2019. The entire disclosures of the applications referenced above are incorporated herein by reference.

FIELD

The present disclosure relates generally to plasma processing systems and more particularly to edge ring systems with a moveable edge ring.

BACKGROUND

The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Substrate processing systems perform treatments on substrates such as semiconductor wafers. Examples of substrate treatments include deposition, ashing, etching, cleaning and/or other processes. Process gas mixtures may be supplied to the processing chamber to treat the substrate. Plasma may be used to ignite the gases to enhance chemical reactions.
A substrate is arranged on a substrate support during treatment. An edge ring is annular and is arranged around and adjacent to a radially outer edge of the substrate. The edge ring may be used to shape or focus the plasma onto the substrate. During operation, the substrate and an exposed surface of the edge ring is etched by the plasma. As a result, the edge ring wears and the effect of the edge ring on the plasma changes over time.

SUMMARY

A moveable edge ring system for a plasma processing system includes a top edge ring and a first edge ring arranged below the top edge ring. A second edge ring is made of conductive material and includes an upper portion, a middle portion and a lower portion. The top edge ring and the second edge ring are configured to move in a vertical direction relative to a substrate support and the first edge ring when biased upwardly by a lift pin. The second edge ring is arranged below the top edge ring and radially outside of the first edge ring.
In other features, the lower portion of the second edge ring extends radially inwardly relative to the middle portion to define a first gap between the lower portion of the second edge ring and a radially outer surface of a substrate support. The middle portion of the second edge ring defines a second gap between the middle portion and the radially outer surface of the substrate support. The second gap is greater than or equal to two times the first gap.
In other features, the middle portion of the second edge ring moves parallel to a radially outer edge of the first edge ring as the lift pin raises the second edge ring and the top edge ring. The top edge ring has an inverted “U”-shape. The top edge ring is made of conductive material. The top edge ring is made of dielectric material. The first edge ring is made of conductive material. The first edge ring is made of dielectric material. The middle portion of the second edge ring extends radially inwardly relative to the upper portion of the second edge ring to define a first annular recess.
In other features, the first edge ring includes a second annular recess on an upper and radially outer surface thereof. A radially inner leg of the top edge ring is located in the first annular recess and the second annular recess when the top edge ring is in a lowered position.
In other features, a third edge ring is located below and radially outside of the first edge ring, the second edge ring and the top edge ring. The third edge ring defines an annular recess on an upper and radially inner surface. A radially outer leg of the top edge ring is located in the annular recess when the top edge ring is in a lowered position.
In other features, the third edge ring includes a vertical bore to receive the lift pin. The second edge ring has a generally rectangular cross-section and a radially inner surface that is parallel to a radially outer edge of a substrate support.
A moveable edge ring system for a plasma processing system includes a top edge ring. A first edge ring is made of dielectric material and includes an embedded conductor that is fully embedded within the dielectric material. The first edge ring lies below the top edge ring. The top edge ring and the first edge ring are configured to move in a vertical direction relative to a substrate support when biased upwardly by a lift pin.
In other features, a second edge ring is arranged below the top edge ring. The first edge ring includes an upper portion, a middle portion and a lower portion. The first edge ring is arranged below the top edge ring and radially outside of the second edge ring.
In other features, the lower portion of the first edge ring extends radially inwardly relative to the middle portion and defines a first gap between the lower portion of the second edge ring and a radially outer surface of the substrate support. The middle portion of the first edge ring defines a second gap between the middle portion and the radially outer surface of the substrate support. The second gap is greater than or equal to two times the first gap.
In other features, the middle portion of the first edge ring moves parallel to a radially outer edge of the second edge ring as the lift pin raises the first edge ring and the top edge ring. The top edge ring has an inverted “U”-shape.
In other features, the embedded conductor includes a horizontal conductor arranged in the upper portion parallel to an upper surface of the first edge ring. The embedded conductor further includes a vertical conductor arranged in the lower portion parallel to a radially inner surface of the first edge ring. The embedded conductor further includes a conductor connecting the vertical conductor and the horizontal conductor. The top edge ring is made of conductive material. The top edge ring is made of dielectric material. The second edge ring is made of dielectric material. The second edge ring is made of conductive material.
In other features, a third edge ring located below and radially outside of the first edge ring, the second edge ring and the top edge ring. The third edge ring defines an annular recess on an upper and radially inner surface. A radially outer leg of the top edge ring is located in the annular recess when the top edge ring is in a lowered position. The third edge ring includes a vertical bore to receive the lift pin.
In other features, the first edge ring is made of ceramic green sheets that include conductive traces and vias.
A moveable edge ring system for a plasma processing system includes a top edge ring. A first edge ring is made of dielectric material and includes a doped region and an undoped region. The doped region is more conductive than the undoped region. The first edge ring lies below the top edge ring. The top edge ring and the first edge ring are configured to move in a vertical direction relative to a substrate support when biased upwardly by a lift pin.
In other features, a second edge ring is arranged below the top edge ring. The first edge ring includes an upper portion, a middle portion and a lower portion. The first edge ring is arranged below the top edge ring and radially outside of the second edge ring.
In other features, the lower portion of the first edge ring extends radially inwardly relative to the middle portion and defines a first gap between the lower portion of the second edge ring and a radially outer surface of the substrate support. The middle portion of the first edge ring defines a second gap between the middle portion and the radially outer surface of the substrate support. The second gap is greater than or equal to two times the first gap.
In other features, the middle portion of the first edge ring moves parallel to a radially outer edge of the second edge ring as the lift pin raises the first edge ring and the top edge ring. The doped region is arranged along an upper surface and a radially inner surface of the first edge ring. The top edge ring has an inverted “U”-shape. The top edge ring is made of conductive material. The top edge ring is made of dielectric material. The second edge ring is made of conductive material. The second edge ring is made of dielectric material.
In other features, a third edge ring is located below and radially outside of the first edge ring, the second edge ring and the top edge ring. The third edge ring defines an annular recess on an upper and radially inner surface. A radially outer leg of the top edge ring is located in the annular recess when the top edge ring is in a lowered position. The third edge ring includes a vertical bore to receive the lift pin.
An edge ring for a plasma processing system includes an annular body that is made of at least one of a dielectric material and a conducting material. The annular body includes an upper portion, a middle portion and a lower portion. A first step projects radially outwardly from a radially inner surface of the annular body between the upper portion and the middle portion. A second step projects radially outwardly from a radially inner surface of the annular body between the middle portion and the lower portion.
In other features, the annular body is made of dielectric material and further comprising an embedded conductor arranged fully inside of the annular body. The embedded conductor includes a horizontal conductor arranged in the upper portion parallel to an upper outer surface of annular body. The embedded conductor further includes a vertical conductor arranged in the lower portion of the annular body parallel to a radially inner surface of the annular body. The embedded conductor further includes a conductor connecting the vertical conductor and the horizontal conductor. The annular body is made of dielectric material and further comprising a doped region and an undoped region. The doped region of the annular body is more conductive than the undoped region. The doped region is arranged on an upper surface and a radially inner surface of the annular body. The annular body is made of ceramic green sheets that include conductive traces and vias.
An edge ring for a plasma processing system includes an annular body that is made of a dielectric material and that is configured to surround a substrate support of the plasma processing system. An embedded conductor is arranged fully inside of the annular body and includes a first conductor arranged in the annular body and a second conductor arranged in the annular body transverse to the first conductor and connected to the first conductor.
In other features, the annular body has an “L”-shaped cross-section. The annular body includes a first leg connected to a second leg. The first conductor is arranged in the first leg and the second conductor is arranged in the second leg.
In other features, the first conductor is arranged parallel to a first outer surface of the annular body. A third conductor is arranged parallel to a second outer surface of the annular body. The second conductor is connected to the first conductor and the third conductor. The annular body includes an upper portion, a middle portion, and a lower portion. A first step is located on and projects radially outwardly from a radially inner surface of the annular body between the upper portion and the middle portion. A second step is located on and projects radially outwardly from a radially inner surface of the annular body between the middle portion and the lower portion.
In other features, the first conductor is arranged parallel to a first outer surface of the annular body in the upper portion. The second conductor is arranged parallel to a radially inner surface of the annular body in the lower portion. A third conductor connects the first conductor to the second conductor. The annular body is made of ceramic green sheets that include conductive traces and vias.
An edge ring for a plasma processing system includes an annular body configured to surround a substrate support of a plasma processing system. An embedded conductor is arranged within the annular body and configured to capacitively couple but not directly couple with at least one external conductive component selected from a group consisting of a baseplate of the substrate support and another edge ring.
An edge ring for a plasma processing system includes an annular body that is made of a dielectric material and that is configured to be arranged around a substrate support. The annular body includes a doped region and an undoped region. The doped region is more conductive than the undoped region.
In other features, the doped region includes a first portion arranged along a radially inner surface of the annular body. The doped region includes a second portion arranged on an upper surface of the annular body. The first portion is in contact with the second portion. The annular body includes an upper portion, a middle portion, and a lower portion. A first step is located on and projects radially outwardly from a radially inner surface of the annular body between the upper portion and the middle portion. A second step is located on and projects radially outwardly from the radially inner surface of the annular body between the middle portion and the lower portion.
In other features, the dielectric material includes silicon carbide. The dielectric material is doped with impurities selected from a group consisting of boron, aluminum or nitrogen.
A moveable edge ring system for a plasma processing system includes a top edge ring. A first edge ring is arranged below the top edge ring and having a rectangular cross-section. A second edge ring is made of a conducting material, has a Z-shaped cross-section and is arranged radially outside of and above the first edge ring. The top edge ring and the second edge ring are configured to move vertically relative to the first edge ring and a substrate support when biased by a lift pin.
In other features, as the second edge ring moves upwardly along the first edge ring from a lowered position to a raised position, the second edge ring maintains a fixed surface area within a predetermined gap of a radially outer surface of the first edge ring. Remaining surface area of the second edge ring is located at a distance greater than or equal to two times the predetermined gap from the first edge ring.
In other features, the second edge ring includes an annular body including an upper portion that projects radially inwardly; a middle portion extending in a vertical direction and connected to the upper portion; a lower portion connected to a lower end of the middle portion and projecting radially-outwardly; and a projection extending radially inwardly from the middle portion and extending downwardly to a lower edge of the lower portion.
In other features, the fixed surface area is defined by the projection. A third edge ring is located below the top edge ring and radially inside of the first edge ring. The third edge ring has an “L”-shaped cross-section. A fourth edge ring is located radially outside of the top edge ring and the second edge ring. The fourth edge ring includes a projection that extends radially inwardly and is arranged between portions of the top edge ring and the second edge ring. The top edge ring has an inverted “U”-shape, a body, an inner leg and an outer leg. The top edge ring lies immediately adjacent to the second edge ring, the third edge ring and the fourth edge ring when in a lowered position.
In other features, the top edge ring is made of conductive material. The top edge ring is made of dielectric material. The first edge ring is made of conductive material.
A moveable edge ring system for a plasma process system includes a first edge ring made of conductive material and configured to surround a substrate support. A lift pin is made of a conductive material. A lift pin actuator is configured to bias the lift pin against the first edge ring when in a lowered position and to selectively move the lift pin to increase a height of the first edge ring relative to the substrate support while maintaining contact between the lift pin and the first edge ring.
In other features, a second edge ring located radially inwardly of and below the first edge ring. The second edge ring is made of dielectric material. The second edge ring has an “L”-shaped cross-section and includes a radially inner leg extending in a vertical direction and a radially outer leg extending in a horizontal direction.
In other features, a third edge ring is located radially outwardly of and below the first edge ring and the second edge ring. The third edge ring is made of dielectric material. The third edge ring has an “L”-shaped cross-section. The first edge ring has a rectangular cross-section.
In other features, the third edge ring includes an annular body; and a radially-inwardly projecting portion including a vertical bore to receive the lift pin.
A moveable edge ring system for a plasma processing system includes a first edge ring made of a dielectric material, including an embedded conductor arranged fully inside of the dielectric material, and configured to surround a substrate support. A lift pin is made of a conductive material. A lift pin actuator is configured to bias the lift pin against the first edge ring when in a lowered position and to selectively move the lift pin to increase a height of the first edge ring relative to the substrate support while maintaining contact between the lift pin and the first edge ring.
In other features, the embedded conductor includes a first horizontal conductor arranged parallel to a top surface of the first edge ring. A second horizontal conductor is arranged parallel to a bottom surface of the first edge ring. A third conductor connects the first horizontal conductor to the second horizontal conductor.
In other features, a second edge ring is located radially inwardly of and below the first edge ring. The second edge ring is made of dielectric material. The second edge ring has an “L”-shaped cross-section and includes a radially inner leg extending in a vertical direction and a radially outer leg extending in a horizontal direction.
In other features, a third edge ring is located radially outwardly of and below the first edge ring and the second edge ring. The third edge ring is made of dielectric material. The third edge ring has an “L”-shaped cross-section. The first edge ring has a rectangular cross-section. The third edge ring includes an annular body; and a radially-inwardly projecting portion including a vertical bore to receive the lift pin.
A moveable edge ring system for a plasma processing system includes a top edge ring having an inverted “U”-shaped cross-section and including an annular body, a radially inner leg, and a radially outer leg. A first edge ring is made of conductive material and is at least partially arranged between the radially inner leg and the radially outer leg of the top edge ring. A second edge ring is made of dielectric material and is arranged between the first edge ring and a substrate support. A third edge ring is arranged below and radially outside of the first edge ring and the second edge ring and including N cavities to receive N lift pins, where N is an integer greater than 2. The top edge ring moves relative to the first edge ring, the second edge ring, the third edge ring and the substrate support when biased by the N lift pins.
In other features, the second edge ring and the third edge ring are made of a dielectric material. The first edge ring has an “L”-shaped cross-section. The second edge ring has an “L”-shaped cross-section. The top edge ring includes N radial recesses spaced 360°/N apart, located on a radially inner surface of the radially outer leg and including an angled lower surface extending radially outwardly from the radial recess. The N lift pins bias the top edge ring in the N radial recesses when adjusting a height of the top edge ring.
An edge ring for a plasma processing system includes an annular body having an inverted “U”-shaped cross-section. A radially inner leg extends from the annular body. A radially outer leg extends from the annular body. N radial recesses spaced 360°/N apart, located on a radially inner surface of the radially outer leg, where N is an integer greater than 2, and including an angled lower surface extending radially outwardly from the N radial recesses.
A moveable edge ring system includes the edge ring. A first edge ring has a “U”-shaped cross-section and includes an annular body, a radially inner leg, and a radially outer leg. The radially inner leg of the edge ring is located between the radially inner leg and the radially outer leg of the first edge ring. A second edge ring is arranged below and radially outside of the edge ring and the first edge ring and includes N vertical bores to receive N lift pins. The edge ring moves relative to the first edge ring, the second edge ring and a substrate support when biased by the N lift pins.
In other features, the first edge ring and the second edge ring are made of a dielectric material. The first edge ring has an “L”-shaped cross-section. The second edge ring has an “L”-shaped cross-section. The edge ring is configured to receive the N lift pins in the N radial recesses when adjusting a height of the edge ring.
A moveable edge ring system includes the edge ring. A first edge ring has an “L”-shaped cross-section and includes a radially inner leg and a vertical leg. The vertical leg of the first edge ring is located between the radially inner leg and the radially outer leg of the edge ring. A second edge ring is arranged radially inward from the first edge ring. A third edge ring is arranged below and radially outside of the edge ring. The first edge ring and the second edge ring and includes a vertical bore to receive a lift pin. The edge ring moves relative to the first edge ring, the second edge ring, the third edge ring and a substrate support when biased by the lift pin.
A moveable edge ring system for a plasma processing system includes a top edge ring having an inverted “U”-shaped cross-section and includes an annular body, a radially inner leg, and a radially outer leg. A first edge ring is made of dielectric material, includes an embedded conductor arranged fully inside of the dielectric material, configures to surround a substrate support and at least partially arranged between the radially inner leg and the radially outer leg of the top edge ring. A second edge ring is made of dielectric material and arranged between the substrate support and the first edge ring. A third edge ring is arranged below and radially outside of the first edge ring and the second edge ring and includes a vertical bore to receive a lift pin. The top edge ring is moveable relative to the first edge ring, the second edge ring and the third edge ring when biased by the lift pin.
In other features, the second edge ring and the third edge ring are made of a dielectric material. The second edge ring has an “L”-shaped cross-section. The first edge ring has an “L”-shaped cross-section. The first edge ring includes an annular body with a vertical leg connected to a horizontal leg. The embedded conductor includes a vertical conductor arranged in the vertical leg and a horizontal conductor arranged in the horizontal leg that communicates with the vertical conductor.
An edge ring for a plasma processing system includes an annular body, a radially inner leg connected to the annular body, and a radially outer leg connected to the annular body. A first portion of an upper surface of the annular body is parallel to a plane including a substrate. A second portion of the upper surface of the annular body slopes downwardly an acute angle from the first portion.
In other features, the first portion of the upper surface is located radially inwardly of the second portion of the upper surface. A third portion of the upper surface is parallel to the plane including the substrate and is located radially outwardly of the second portion of the upper surface.
A moveable edge ring system includes the edge ring. A first edge ring is made of conductive material, is configured to surround a substrate support and is at least partially arranged between the radially inner leg and the radially outer leg of the edge ring.
In other features, a second edge ring is made of dielectric material and is arranged between the first edge ring and the substrate support. A third edge ring is arranged below and radially outside of the first edge ring and the second edge ring and includes a vertical bore to receive a lift pin. The edge ring moves relative to the first edge ring, the second edge ring, and the substrate support when biased by a lift pin.
An edge ring for a plasma processing system includes an annular body with a rectangular cross-section. A radially-inwardly projecting leg extends from a radially inner and upper surface of the annular body. A radially inner portion of an upper surface of the annular body is arranged parallel to a plane including a substrate.
In other features, a radially outer portion of the upper surface of the annular body sloping downwardly an acute angle from the radially inner portion.
A moveable edge ring system for a plasma processing system includes the edge ring. A middle edge ring is arranged below the radially-inwardly projecting leg and radially inside of the annular body. An outer edge ring is arranged below the edge ring and the middle edge ring and includes a vertical bore to receive a lift pin. The edge ring moves vertically relative to the middle edge ring and the outer edge ring when biased by the lift pin.
In other features, the middle edge ring has a generally rectangular cross section and an annular recess on a radially inner and upper surface thereof. The substrate is arranged in the annular recess. The outer edge ring includes a radially outer portion and an inner portion that extends radially inwardly from a middle portion of the radially outer portion.
In other features, the outer edge ring includes a projection on an upper and radially inner surface of the inner portion. The projection lies adjacent to a junction between a heating plate and a baseplate of a substrate support. A bottom portion of the annular body is located adjacent to an upper surface of the outer edge ring between the radially outer portion and the projection.
A plasma processing system includes the moveable edge ring system. A substrate support includes a baseplate. A heating plate is bonded to the baseplate. The heating plate includes a body including a plurality of radio frequency (RF) electrodes, a cylindrical portion and a projecting portion extending radially outwardly from the cylindrical portion below the middle edge ring.
In other features, the plurality of RF electrodes are not located in portions of the projecting portion located below the middle edge ring.
A moveable edge ring system for a plasma processing system includes a top edge ring configured to surround a substrate support. The moveable edge ring system includes an annular body; a radially outer leg projecting downwardly from a radially outer surface of the annular body; a radially inner leg projecting downwardly from a radially inner surface of the annular body; and an inwardly projecting leg extending radially inwardly from a lower end of the radially inner leg. The inwardly projecting leg is arranged below a substrate when the substrate is arranged on the substrate support. A first edge ring is configured to surround a substrate support, is arranged below the top edge ring and includes an annular body and a radially inwardly projecting leg. An upper surface of the first edge ring is arranged between the radially inner leg and the radially outer leg of the top edge ring when the first edge ring is biased against the top edge ring.
In other features, a second edge ring arranged radially outside of the top edge ring and the first edge ring. The second edge ring includes an annular body; a radially outwardly projecting leg extending from an upper and radially outer surface of the annular body; and a radially inwardly projecting leg extending radially inwardly from a radially inner and lower surface of the annular body.
In other features, the inwardly projecting leg of the first edge ring extends radially inwardly from an upper and radially inner surface of the annular body of the first edge ring. A third edge ring is arranged radially outside of the first edge ring and below the top edge ring, the first edge ring and the second edge ring. The third edge ring includes an annular body; a radially downwardly projecting leg extending from a radially outer and lower surface of the third edge ring; and an inwardly projecting leg extending radially inwardly from a middle portion of the third edge ring.
In other features, the inwardly projecting leg of the third edge ring includes a vertical bore that receives a lift pin. When biased against the top edge ring, the first edge ring defines a first vertical gap between a lower surface of the radially inner leg of the first edge ring and a surface of the substrate support; and a second vertical gap between a lower surface of the first edge ring and an upper surface of the inwardly projecting leg of the third edge ring.
In other features, when in a lowered position, the first edge ring abuts the inwardly leg of the third edge ring and projecting defines a third vertical gap between an upper surface of the first edge ring and a lower surface of the top edge ring.
A plasma processing system includes a processing chamber. The substrate support is arranged in the processing chamber. The processing chamber includes a substrate port. A robot arm deliver substrates onto the substrate support. The moveable edge ring system is arranged around the substrate support. A lift pin biases the top edge ring and the first edge ring relative to the substrate support.
In other features, the first edge ring and the top edge ring are raised relative to the substrate support by the lift pin, the robot arm removes the top edge ring and the robot arm delivers another top edge ring to the substrate support through the substrate port.
An edge ring system for a plasma processing system includes an upper ring including a first annular body configured to surround a substrate support during plasma processing. A lower ring includes a second annular body configured to surround the substrate support during plasma processing. At least a portion of the second annular body of the lower ring is nested within and defines a predetermined gap relative to a portion of the first annular body of the upper ring when configured for plasma processing. N spacers are arranged in N spaced locations on a surface of at least one of the upper ring and the lower ring to reduce variations in the predetermined gap between the annular body of the upper ring and the annular body of the lower ring as the upper ring and the lower ring are heated and cooled during plasma processing, where N is an integer greater than or equal to 3 and less than or equal to 8.
In other features, at least one of the N spacers includes a shim located in a slot on a radially facing surface of the at least one of the upper ring and the lower ring. The shim has a rectangular cross-section. The slot is located on a radially outer surface of the inner ring. At least one of the N spacers includes a pin located in a slot on a surface of the at least one of the upper ring and the lower ring. The slot is located on a radially outer surface of the inner ring. The N spacers are arranged with a spacing of 360°/N.
In other features, at least one of the N spacers includes a projection formed on a surface of the at least one of the upper ring and the lower ring. The projection is located on a radially outer surface of the inner ring. A coating covers the projection. The coating includes an insulating material.
In other features, the coating is selected from a group consisting of polytetrafluoroethylene (PTFE), perfluoroalkoxy polymer (PFA), aluminum oxide deposited using atomic layer deposition, yttrium oxide deposited using atomic layer deposition, and yttrium fluoride deposited using atomic layer deposition. In other features, N=5. A lift pin lifts the upper ring relative to the lower ring to adjust a height of a top surface of the upper edge ring relative to a substrate on the substrate support.
An edge ring for a plasma processing system includes a first annular body configured to surround a substrate support during plasma processing. At least a portion of the first annular body is configured to nest within and define a predetermined gap relative to a portion of a second annular body of an upper ring exposed to plasma during plasma processing. N spacers are arranged in N spaced locations on at least one of a radially inner surface and a radially outer surface of the annular body to reduce variations in the predetermined gap as the upper ring and the lower ring are heated and cooled during plasma processing, where N is an integer greater than or equal to 3 and less than or equal to 7.
In other features, at least one of the N spacers includes a shim located in a slot on the at least one of the radially inner surface and the radially outer surface of the annular body. The shim has a rectangular cross-section. The slot is located on the radially outer surface of the first annular body. At least one of the N spacers includes a pin located in a slot on the at least one of the radially inner surface and the radially outer surface of the first annular body. The slot is located on the radially outer surface of the first annular body.
In other features, the N spacers are arranged with a spacing of 360°/N. At least one of the N spacers includes a projection formed on the at least one of the radially inner surface and the radially outer surface of the first annular body. The projection is located on a radially outer surface of the inner ring. A coating covers the projection. The coating includes an insulating material. The coating is selected from a group consisting of polytetrafluoroethylene (PTFE), perfluoroalkoxy polymer (PFA), aluminum oxide deposited using atomic layer deposition, yttrium oxide deposited using atomic layer deposition, and yttrium fluoride deposited using atomic layer deposition. In other features, N=5.
Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1A is a functional block diagram of an example of a substrate processing system according to the present disclosure;

FIGS. 1B and 1C are cross-sectional views of examples of a moveable edge ring according to the present disclosure;

FIG. 2 is a functional block diagram of another example of a substrate processing system according to the present disclosure;

FIG. 3A is a cross-sectional side view of an example of a moveable edge ring according to the present disclosure;

FIG. 3B is an electrical schematic modelling the moveable edge ring in FIG. 3A;

FIG. 4 is a cross-sectional side view of another example of a moveable edge ring according to the present disclosure;

FIGS. 5A and 5B are illustrations showing movement of different surfaces of the moveable edge ring relative to adjacent structures;

FIGS. 6A to 6D are cross-sectional side views of another example of a moveable edge ring according to the present disclosure;

FIGS. 7A to 7B are cross-sectional side views of another example of a moveable edge ring according to the present disclosure;

FIGS. 8A to 8C are cross-sectional side views of another example of a moveable edge ring according to the present disclosure;

FIGS. 9A to 9C are cross-sectional side views of another example of a moveable edge ring according to the present disclosure;

FIG. 9C1 is a partial bottom view of a portion top edge ring according to the present disclosure;

FIG. 9C2 is a cross-sectional view of a portion of the top edge ring according to the present disclosure;

FIGS. 9D to 9G are cross-sectional side views of another example of a moveable edge ring according to the present disclosure;

FIGS. 10A and 10B are cross-sectional side views of another example of a moveable edge ring including an embedded conductor according to the present disclosure;

FIGS. 11A and 11B are cross-sectional side views of another example of a moveable edge ring including an embedded conductor according to the present disclosure;

FIGS. 11C to 11E are cross-sectional views of examples of the moveable edge ring and the embedded conductor according to the present disclosure;

FIGS. 12A and 12B are cross-sectional side views of another example of a moveable edge ring including an embedded conductor according to the present disclosure;

FIGS. 13A and 13B are cross-sectional side views of another example of a moveable edge ring including doped conductive portions according to the present disclosure;

FIGS. 14A, 14B, and 14C are cross-sectional side views of another example of a moveable edge ring according to the present disclosure;

FIG. 15 is a cross-sectional side view of another example of a moveable edge ring according to the present disclosure;

FIGS. 16A to 16D are cross-sectional side views of other examples of moveable edge rings according to the present disclosure;

FIG. 17 is a cross-sectional view of a portion of upper and lower edge rings according to the present disclosure;

FIG. 18 is a graph illustrating increase in capacitance as a function of shift percentage from a nominal gap according to the present disclosure;

FIG. 19 is a side cross-sectional view of an edge ring system including an upper ring and a lower ring according to the present disclosure;

FIG. 20 is a side cross-sectional view of an edge ring system including an upper ring and a lower ring including a plurality of shims according to the present disclosure;

FIG. 21 is a side cross-sectional view of an edge ring system including an upper ring and a lower ring including a plurality of pins according to the present disclosure;

FIG. 22A is a side cross-sectional view of an edge ring system including an upper ring and a lower ring including a plurality of projections according to the present disclosure; and

FIG. 22B is an enlarged side cross-sectional view of a lower edge ring including a projection with a raised flat portion according to the present disclosure.

In the drawings, reference numbers may be reused to identify similar and/or identical elements.

DETAILED DESCRIPTION

During substrate processing, a substrate is arranged on a pedestal such as an electrostatic chuck (ESC), process gases are supplied, and plasma is struck in the processing chamber. Exposed surfaces of components within the processing chamber experience wear due to the plasma.
For example, an edge ring is arranged around a radially outer edge of the substrate to shape the plasma. After processing substrates, the exposed surface of the edge ring is worn down and sits at a different height relative to the substrate. As a result, the effect of the edge ring on the plasma changes, which alters the effects of the process on the substrates. To reduce process changes due to edge ring wear without breaking vacuum, some processing chambers increase the height of the edge ring to compensate for wear. In many of these systems, the height of the edge ring is automatically adjusted based upon the number of cycles and/or the total plasma processing exposure period. Other systems measure the height of the edge ring and adjust the height based on the measured height.
As the height of the edge ring is adjusted, capacitive coupling between the plasma, the sheath and/or capacitance delivery structures (including the edge ring) changes. These changes in capacitive coupling can cause substrate processing non-uniformities over time. Various edge ring arrangements according to the present disclosure significantly reduce changes in capacitance of the delivery structures due to changes in the height of the edge ring.
More particularly, the plasma sheath is created between the plasma and the delivery components. In some examples, an RF bias is output to the substrate support. To maintain control of the sheath at low RF bias frequencies (e.g. less than 5 MHz, or less than 1 MHz) to ensure process uniformity, the capacitance value of the delivery components to the substrate support needs to be maintained as a height of the edge ring is adjusted to compensate for wear. Areas of the edge ring and/or nearby structures that capacitively couple are designed to minimize changes in capacitive coupling as the top edge ring is moved. In some examples, capacitance is minimized in areas that move apart as the height of the edge ring is increased. Capacitance is controlled in other surface areas that do not change (or change less) as the height of the edge ring is increased.
In some examples, the edge ring is made of conductive material. As used herein, conductive materials refer to materials with a resistivity of less than or equal to 104 Ωcm. For example, doped silicon has a resistivity of 0.05 Ωcm, silicon carbide has a resistivity of 1-300 Ωcm and metals such as aluminum and copper have a resistivity of≈10-7 Ωcm. In other examples, the edge ring is made of a non-conductive or dielectric material (resistivity >104 Ωcm) with an embedded conductive electrode. The embedded electrode is designed to minimize changes in capacitive coupling as the top edge ring is moved. In other examples, the edge ring is made of a dielectric material and includes doped regions that are more conductive than undoped regions. The doped regions are designed to minimize changes in capacitive coupling as the edge ring is moved to offset wear.
Referring now to FIGS. 1A and 2, examples of plasma processing chambers that use movable edge rings are shown. As can be appreciated, other types of plasma processing chambers can be used. In FIG. 1A, an example of a substrate processing system 110 according to the present disclosure is shown. The substrate processing system 110 may be used to perform etching using capacitively coupled plasma (CCP). The substrate processing system 110 includes a processing chamber 122 that encloses other components of the substrate processing system 110 and contains the RF plasma (if used). The substrate processing system 110 includes an upper electrode 124 and a substrate support 126 such as an electrostatic chuck (ESC). During operation, a substrate 128 is arranged on the substrate support 126.
For example only, the upper electrode 124 may include a gas distribution device 129 such as a showerhead that introduces and distributes process gases. The gas distribution device 129 may include a stem portion including one end connected to a top surface of the processing chamber. An annular body is generally cylindrical and extends radially outwardly from an opposite end of the stem portion at a location that is spaced from the top surface of the processing chamber. A substrate-facing surface or faceplate of the annular body of the showerhead includes a plurality of holes through which precursor, reactants, etch gases, inert gases, carrier gases, other process gases or purge gas flows. Alternately, the upper electrode 124 may include a conducting plate and the process gases may be introduced in another manner.
The substrate support 126 includes a baseplate 130 that acts as a lower electrode. The baseplate 130 supports a heating plate 132, which may correspond to a ceramic multi-zone heating plate. A bonding and/or a thermal resistance layer 134 may be arranged between the heating plate 132 and the baseplate 130. The baseplate 130 may include one or more channels 136 for flowing coolant through the baseplate 130.
An RF generating system 140 generates and outputs an RF voltage to one of the upper electrode 124 and the lower electrode (e.g., the baseplate 130 of the substrate support 126). The other one of the upper electrode 124 and the baseplate 130 may be DC grounded, AC grounded or floating. For example only, the RF generating system 140 may include an RF generator 142 that generates RF plasma power that is fed by a matching and distribution network 144 to the upper electrode 124 or the baseplate 130. In other examples, the plasma may be generated inductively or remotely.
A gas delivery system 150 includes one or more gas sources 152-1, 152-2, . . . , and 152-N (collectively gas sources 152), where N is an integer greater than zero. The gas sources 152 are connected by valves 154-1, 154-2, . . . , and 154-N (collectively valves 154) and MFCs 156-1, 156-2, . . . , and 156-N (collectively MFCs 156) to a manifold 160. Secondary valves may be used between the MFCs 156 and the manifold 160. While a single gas delivery system 150 is shown, two or more gas delivery systems can be used.
A temperature controller 163 may be connected to a plurality of thermal control elements (TCEs) 164 arranged in the heating plate 132. The temperature controller 163 may be used to control the plurality of TCEs 164 to control a temperature of the substrate support 126 and the substrate 128. The temperature controller 163 may communicate with a coolant assembly 166 to control coolant flow through the channels 136. For example, the coolant assembly 166 may include a coolant pump, a reservoir and/or one or more temperature sensors. The temperature controller 163 operates the coolant assembly 166 to selectively flow the coolant through the channels 136 to cool the substrate support 126.
A valve 170 and pump 172 may be used to evacuate reactants from the processing chamber 122. A system controller 180 may be used to control components of the substrate processing system 110. An edge ring 182 may be arranged radially outside of the substrate 128 during plasma processing. An edge ring height adjustment system 184 may be used to adjust a height of a top surface of the edge ring 182 relative to the substrate 128 as will be described further below. In some examples, the edge ring 182 can also be raised, removed by a robot end effector and replaced with another edge ring without breaking vacuum.
Referring now to FIGS. 1B and 1C, in some examples the substrate 128 rests on an upper surface 190 of the substrate support 126 (or ESC). In FIG. 1B, the edge ring 182 rests on a middle edge ring 186 and a bottom edge ring 188. The middle edge ring 186 and the bottom edge ring 188 are not moved. The edge ring 182 defines a height h above the upper surface 190 when the edge ring 182 is resting on the middle edge ring 186 and the bottom edge ring 188 and the edge ring 182 is not worn. One or more openings 192 may be defined in one or more of the substrate support 126, the middle edge ring 186 and/or the bottom edge ring 188 to allow a height adjuster to adjust the height of the edge ring 182 as will be described further below.
In FIG. 1C, the edge ring 182 is worn and the thickness is reduced to a height h′ (h′<h). The height adjuster is used to raise the edge ring 182 to restore the height relationship h between a top surface of the edge ring 182 and the upper surface 190. When the edge ring 182 is sufficiently worn, the edge ring 182 can be replaced with a new edge ring.
In FIG. 2, an example of a substrate processing system 210 according to the present disclosure is shown. The substrate processing system 210 uses inductively coupled plasma to perform etching. The substrate processing system 210 includes a coil driving circuit 211. A pulsing circuit 214 may be used to pulse the RF power on and off or vary an amplitude or level of the RF power. The tuning circuit 213 may be directly connected to one or more inductive coils 216. The tuning circuit 213 tunes an output of the RF source 212 to a desired frequency and/or a desired phase, matches an impedance of the coils 216 and splits power between the coils 216. In some examples, the coil driving circuit 211 is replaced by one of the drive circuits described further below in conjunction with controlling the RF bias.
In some examples, a plenum 220 may be arranged between the coils 216 and a dielectric window 224 to control the temperature of the dielectric window 224 with hot and/or cold air flow. The dielectric window 224 is arranged along one side of a processing chamber 228. The processing chamber 228 further comprises a substrate support (or pedestal) 232. The substrate support 232 may include an electrostatic chuck (ESC), or a mechanical chuck or other type of chuck. Process gas is supplied to the processing chamber 228 and plasma 240 is generated inside of the processing chamber 228. The plasma 240 etches an exposed surface of the substrate 234. A drive circuit 252 (such as one of those described below) may be used to provide an RF bias to an electrode in the substrate support 232 during operation.
A gas delivery system 256 may be used to supply a process gas mixture to the processing chamber 228. The gas delivery system 256 may include process and inert gas sources 257, a gas metering system 258 such as valves and mass flow controllers, and a manifold 259. A gas delivery system 260 may be used to deliver gas 262 via a valve 261 to the plenum 220. The gas may include cooling gas (air) that is used to cool the coils 216 and the dielectric window 224. A heater/cooler 264 may be used to heat/cool the substrate support 232 to a predetermined temperature. An exhaust system 265 includes a valve 266 and pump 267 to remove reactants from the processing chamber 228 by purging or evacuation.
A controller 254 may be used to control the etching process. The controller 254 monitors system parameters and controls delivery of the gas mixture, striking, maintaining and extinguishing the plasma, removal of reactants, supply of cooling gas, and so on. Additionally, as described below in detail, the controller 254 may control various aspects of the coil driving circuit 211 and the drive circuit 252. An edge ring 282 may be located radially outside of the substrate 234 during plasma processing. A height adjustment system 284 may be used to adjust a height of a top surface of the edge ring 282. In addition, the edge ring 282 may optionally be removed when worn and replaced with a new edge ring without breaking vacuum. The controller 254 may be used to control the height adjustment system 284.
During processing, plasma is struck in the processing chamber. In some examples, an RF bias is output to the substrate support. To maintain control of a sheath of the plasma at low bias frequencies, a capacitance CD of delivery components (such as top, middle and bottom edge rings) to the substrate support needs to be maintained as a height of the top edge ring is adjusted due to wear. In the examples that follow, the edge rings are made of conductive material or a dielectric material with an embedded electrode. As will be described further below, areas providing capacitive coupling are designed to minimize changes in capacitive coupling as the top edge ring is moved.
Referring now to FIG. 3A, an edge ring system for a substrate support includes a top edge ring 310, a middle edge ring 314 and a bottom edge ring 316. The top edge ring 310 has an inverted “U”-shape and includes an annular body 330 connected to a radially inner leg 332 and a radially outer leg 334. The middle edge ring 314 has a “U”-shape and includes an annular body 340 connected to a radially inner leg 342 and a radially outer leg 344. The radially inner leg 332 of the top edge ring 310 is located between the radially inner leg 342 and the radially outer leg 344 of the middle edge ring 314.
The bottom edge ring 316 includes a radially outer portion 350, a middle portion 352 and a radially inner portion 354. An annular recessed portion 360 is arranged on an upper and radially inner surface of the bottom edge ring 316 between the radially outer portion 350 and the middle portion 352. An annular recessed portion 364 is arranged on an upper and radially inner surface of the bottom edge ring 316 between the radially inner portion 354 and the middle portion 352. The bottom edge ring 316 includes an elongate vertical bore 374 configured to receive a lift pin 372 that is used to raise and lower the top edge ring 310. Likewise, the baseplate 130 may include an elongate vertical bore 376 that is configured to receive the lift pin 372 and that is aligned with the elongate vertical bore 370. While a single lift pin is shown, N lift pins may be used where N is an integer greater than 2. In some examples, the N lift pins are spaced apart by an angle equal to 360°/N.
During operation, plasma 380 is generated. A sheath 390 forms between the plasma 380 and delivery components 392 (including the top edge ring 310, the middle edge ring 314 and/or the bottom edge ring 316).
Referring now to FIG. 3B, an electrical model of the plasma, the sheath and the delivery components 392 is shown. The sheath 390 has a sheath capacitance CS and delivery components 392 have a delivery capacitance CD. If the capacitance of the delivery components 392 varies in response to component wear or the adjustment of the height of the edge ring, the process will be less uniform and performance variations and/or defects may occur.
Referring now to FIG. 4, various parameters can be adjusted to vary the capacitance of the delivery components. In FIG. 4, a top edge ring 420 has an inverted “U”-shape and includes a radially inner leg 422 connected by an annular body 424 to a radially outer leg 426. A middle edge ring 430 has a “U”-shape and includes a radially outer leg 432 connected by an annular body 436 to a radially inner leg 438. The radially inner leg 422 of the top edge ring 420 is arranged between the radially inner leg 438 and the radially outer leg 432 of the middle edge ring 430. Electrostatic electrodes 410 and RF electrodes 412 of the baseplate 130 are shown.
A bottom edge ring 440 includes a middle portion 444, an upper portion 446 that projects upwardly from the middle portion 444 adjacent to a radially outer edge of the bottom edge ring 440 and a lower portion 448 that projects downwardly from the middle portion 444 adjacent to the radially outer edge of the bottom edge ring 440. The bottom edge ring 440 includes a radially inner portion 450 with an upward projection 452 on an upper, radially inner surface thereof. The baseplate 130 includes a stepped portion 456 that receives the radially inner portion 450 of the bottom edge ring 440. Cavities 462 and 464 in the bottom edge ring 440 and the baseplate 130, respectively, reciprocally receive a lift pin 470.
In some examples, the top edge ring 420 and the middle edge ring 430 are made of conductive material and the bottom edge ring 440 is made of non-conductive material such as dielectric. In some examples, the lift pin 470 is made of conductive or non-conductive material such as dielectric.
Referring now to FIGS. 5A and 5B, the coupling capacitance between two conducting surfaces decreases significantly as the gap between the facing surfaces increases. As the edge ring is raised, facing surfaces in A areas generally maintain the same gap DA. In contrast, the gap DB of facing surfaces in B areas increases proportionately as the edge ring is raised. The coupling capacitance of facing conductive surfaces will be affected by both the A areas and the B areas. The A areas will have a stable coupling capacitance as the edge ring is moved and the B areas will have a decreasing coupling capacitance as the edge ring is moved.
According to the present disclosure, the coupling capacitance in the A areas is maximized since it is relatively constant while the coupling capacitance in the B areas is minimized since it is changing. In some examples, the gap DA for the A areas is set to a minimum value and the gap DB for the B areas is set to k*DA, where k is a number greater than or equal to 2. In some examples, k is equal to 3. In some examples, the gaps are set to a gap less than or equal to 0.006″ or 6 mils for areas where coupling is desired and greater than or equal to 0.012″ or 12 mils is areas where coupling is not desired. In some examples, the gaps are set to a gap less than or equal to 0.006″ or 6 mils for areas where coupling is desired and greater than or equal to 0.018″ or 18 mils is areas where coupling is not desired.
In FIGS. 5A and 5B, facing surfaces of the edge ring bodies are shown during movement. In the A areas, facing surfaces of the edge rings slide adjacent to one another without significantly changing the gap DA therebetween. In the B areas, facing surfaces of the edge rings slide apart and increase the gap DB therebetween.
In some examples, the gap DA is set based on a minimum gap (dmin) between facing surfaces in the A areas. The minimum gap dmin is determined based on tolerances of the delivery components and/or thermal expansion for a given process temperature range. The gap DA is set equal to a minimum gap dmin in the A areas where the capacitance needs to be constant. In other areas where the capacitance is to be minimized (since the gap between facing surfaces increases), the gap DB is set greater than or equal to k*dmin (where k is a number greater than or equal to 2). In other examples, k is greater than or equal to 3. As a result, the capacitance due to the A areas dominates the delivery capacitance while the capacitance due to the B areas has a significantly reduced impact on the delivery capacitance.
Referring now to FIGS. 6A and 6B, an edge ring 610 has a “U”-shape and includes an inner leg 612 connected by an annular body 614 to an outer leg 616. A recessed portion 618 is located between the inner leg 612 and the outer leg 616. A top edge ring 620 has an inverted “U”-shape and includes an inner leg 622 that is connected by an annular body 624 to an outer leg 626.
An edge ring 630 includes a radially inwardly projecting upper portion 632 connected by a middle portion 634 to a radially outwardly projecting portion 636. In some examples, the edge ring 630 has a “Z”-shaped cross-section. A projecting surface 638 extends radially inwardly from a middle region of the middle portion 634 down (towards a facing surface 639 of an edge ring 640) to a lower edge of the edge ring 630.
An edge ring 640 is located radially inwardly from the edge ring 630 and below the upper portion 632 of the edge ring 630. The edge ring 640 includes a body 642 having a generally rectangular cross-section, an upper portion 644, a lower portion 646 and a projecting portion 648 that projects downwardly from a lower, radially-inner surface of the edge ring 640. An outer edge ring 650 includes a body 652, a radially inwardly projecting portion 654 that projects radially inwardly adjacent to an upper surface of the body 652 and a downwardly projecting portion 656 that projects downwardly from a radially outer surface of the outer edge ring 650. Annular recesses 658 and 659 provide clearance for the radially outwardly projecting portion 636 and the baseplate 130, respectively.
An annular seal 660 is arranged in an annular slot 661 defined between the baseplate 130, the heating layer 132 and the edge ring 640 to protect the bonding and/or a thermal resistance layer 134 arranged between the heating layer 132 and the baseplate 130. A lift pin 662 passes through a guide sleeve 664 that is arranged in a vertical bore 666 in the baseplate 130.
The top edge ring 620 rests on the edge ring 630. The inner leg 622 of the top edge ring 620 is located between the inner leg 612 of the edge ring 610 and the radially inwardly projecting upper portion 632 of the edge ring 630. The edge ring 610 rests on a stepped surface of the heating layer 132. The edge ring 640 lies radially outside of the heating layer 132 and the edge ring 610. The body 652 of the outer edge ring 650 lies radially outside of the edge ring 630. The inwardly projecting portion 654 of the outer edge ring 650 is arranged between the outer leg 626 of the top edge ring 620 and the radially outwardly projecting portion 636 of the edge ring 630. A vertical gap 690 is defined between the edge ring 630 and the edge ring 610. A horizontal gap 691 is defined between upper portions of the edge rings 630 and 640. A vertical gap is defined between the edge ring 630 and the outer edge ring 650.
In FIG. 6B, as the top edge ring 620 is worn, the lift pin 662 moves upwardly to bias the edge ring 630 upwardly to compensate the top edge ring 620 for wear due to exposure to plasma and/or other process gas mixtures. As can be seen, the projecting portion 638 is arranged within the gap DA of the edge ring 640. Likewise, a top surface of the edge ring 630 is arranged within the gap DA of a bottom surface of the annular body. The minimum gap between lower portions of the edge rings 630 and 640 is maintained for consistent capacitive coupling. Other gaps that increase start with a larger gap (≥ two times the minimum gap) and then increase to reduce the impact on the capacitive coupling. Gaps that decrease start and remain larger than two times the minimum gap to reduce the impact on the capacitive coupling.
Referring now to FIG. 6C, example variations of the edge ring 630 are shown. The upper portion 632 of the edge ring 630′ extends downwardly adjacent to an upper surface of the outer leg 616 of the edge ring 610 and adjacent to an upper surface of the upper portion 644 of the edge ring 640. An inner surface 637 of the edge ring 630 extends parallel to (and within a predetermined fixed distance of) a radially outer surface 641 of the edge ring 630. In some examples, the base height (e.g. a top surface of the top edge ring to a top surface of the heating layer 132) is in a range from 1 mm to 6 mm. In some examples, the base height is 4 mm. In some examples, a gap between a bottom surface of the upper portion 632 of the edge ring 630′ is in a range from 0.1 mm to 1 mm. In some examples, a gap between a bottom surface of the upper portion 632 of the edge ring 630′ is in a range from 0.1 mm or 0.5 mm. Increasing gaps reduces coupling therebetween and vice versa.
In some examples, the top edge ring 620 is made of quartz, the edge ring 630′ is made of silicon or silicon carbide the edge ring 610 is made of quartz and the edge ring 640 is made of silicon or silicon carbide, although other materials can be used.
Referring now to FIG. 6D, other variations of an edge ring 630″ and a top edge ring 620′ are shown. The upper portion 632 of the edge ring 630′ extends less radially inward relative to the edge rings 630 and 630′ shown above. The inner leg 622 of the top edge ring 620′ is wider in a radial direction (and extends further radially outwardly).
In some examples, the top edge ring 620 is made of quartz, the edge ring 630″ is made of silicon or silicon carbide, the edge ring 610 is made of quartz and the edge ring 640 is made of silicon or silicon carbide, although other materials can be used.
Referring now to FIGS. 7A and 7B, a top edge ring 710 has a rectangular cross-section. A middle edge ring 720 is “L”-shaped and includes a vertical leg 722 connected to a radially outwardly projecting leg 726. A bottom edge ring 740 includes an annular body 744, an upwardly projecting portion 742, a downwardly projecting portion 749, and an inwardly projecting portion 745.
A vertical bore 746 passes through the inwardly projecting portion 745 to allow a lift pin 754 to pass reciprocally and move the top edge ring 710. The inwardly projecting portion 745 includes an upwardly projecting portion 747 located adjacent to the pin 754 to define an annular recess to receive the outwardly projecting leg 726. The inwardly projecting portion 745 also includes a downwardly projecting portion 748 located near the radially inner surface of the bottom edge ring 740. A guide sleeve 750 is located in an annular recess defined by the downwardly projecting portion 748.
In some examples, the top edge ring 710 and the lift pin 754 are made of conductive material. The middle edge ring 720 and the bottom edge ring 740 are non-conductive and made of dielectric material. Capacitive coupling is maintained through the lift pin 754, which is conductive and in contact with the top edge ring 710, as the top edge ring 710 is raised in FIG. 7B.
Referring now to FIGS. 8A and 8B, a top edge ring 810 has an inverted “U”-shape and includes an annular body 812 connected to an inner leg 814 and an outer leg 816. An outer edge ring 820 includes a middle portion 822, a lower portion 824 and an upper portion 828. The middle portion 822 projects radially inwardly below the upper portion 828 to form an annular recess 826 or step to receive the outer leg 816 of the top edge ring 810 when the top edge ring 810 is lowered. The lower portion 824 projects radially inwardly towards the baseplate 130 to form a step 829.
An edge ring 840 is located below the top edge ring 810 between the outer edge ring 820 and the baseplate 130. The edge ring 840 includes a middle portion 842, an upper portion 843 and a lower portion 844. The edge ring 840 extends radially inwardly to form an annular recess 846 or step between the middle portion 842 and the upper portion 843. The edge ring 840 extends radially inwardly to form an annular recess 848 or step between the middle portion 842 and the lower portion 844. The edge ring 840 includes a lower surface 849 that is located within the gap DA of a facing surface of the baseplate 130. Other surfaces of the edge ring 840 that face the baseplate 130 and vary with movement (as shown in FIG. 8B) are located with the gap DB of the facing surface of the baseplate 130.
An edge ring 850 includes a body portion 852 having a generally rectangular cross-section. An annular recess or step 854 is located at an upper and radially outer portion of the body portion 852. The inner leg of the top edge ring 810 is located in the annular recesses 846 and 854.
In some examples, the top edge ring 810 is made of conductive or dielectric material, the edge ring 850 and the outer edge ring 820 are made of dielectric material, and the edge ring 840 is made of conductive material. While the lift pin 870 is shown passing through a vertical bore in the edge ring 820, the baseplate 130 can extend radially outwardly further and the lift pin can pass through the baseplate 130 instead of the edge ring 820. In some examples, radially inwardly facing surfaces of the lower portion 844 and the middle portion 842 are parallel to radially outwardly facing surface of the baseplate 130.
A first surface area of the lower portion 844 of the edge ring 840 that is in close proximity to (and facing) the baseplate 130 remains the same as the top edge ring 810 and the edge ring 840 are raised and lowered. A second surface area of the middle portion 842 of the edge ring 840 that is located further away from the baseplate 130 decreases as the edge ring is raised (since the edge ring 850 is located therebetween).
Referring now to FIG. 8C, an edge ring 870 has a generally rectangular cross-section, an upper portion 872 and a lower portion 874. An annular seal 876 is arranged around an upper surface of the baseplate 130 radially outside of the bonding and/or thermal resistance layer 134 below the heating plate 132. An edge ring 880 has an “L”-shaped cross-section and is located between the edge ring 870 and the heating plate 132. An annular recess 882 or step is arranged on an upper, radially inner surface of the edge ring 880.
A top edge ring 884 has an inverted “U”-shape, an annular body 885, a radially inner leg 886 and a radially outer leg 888. An outer edge ring 892 has a generally rectangular cross-section and is arranged radially outside of the edge rings 870 and 884. The outer edge ring 892 has a generally rectangular cross-section, a radially-inner and upper annular recess 894 or step to receive the radially outer leg 888, and a radially-inner and lower annular recess 896 or step to receive a lower, radially outer portion of the baseplate 130.
Referring now to FIGS. 9A and 9B, a top edge ring 910 has an inverted “U”-shape and includes an annular body 912, an inner leg 914 and an outer leg 916. In some examples, the outer leg 916 is P times thicker in a radial direction than the inner leg 914 where P is greater than or equal to 2 and less than or equal to 5. An edge ring 920 is generally “L”-shaped and includes an upwardly-directed leg 922 and a radially-inwardly directed leg 924. An edge ring 930 is generally “L”-shaped and includes an upwardly-directed leg 932 and a radially outwardly directed leg 934 having a radially outer portion lying adjacent to a radially inner portion of the radially-inward directed leg 924 of the edge ring 920.
A bottom edge ring 940 includes a middle portion 942. An upwardly-directed portion 944 extends from a radially-outer, upper surface of the bottom edge ring 940. A downwardly-directed portion 948 extends from a radially-outer lower surface of the bottom edge ring 940. A radially inner portion 946 of the bottom edge ring extends radially inwardly beneath the outer leg 916 of the top edge ring 910 and a portion of the edge ring 920. An upwardly-directed projection 949 extends upwardly from a radially inner surface of the radially inner portion 946 by a predetermined distance.
In some examples, the edge ring 920 and the top edge ring 910 are made of conductive material. In some examples, the edge rings 930 and 940 are made of dielectric material.
The outer leg 916 of the top edge ring 910 extends a predetermined distance lower than a lowermost surface of the edge ring 920 when the top edge ring is fully lowered. As a result, facing surfaces of the top edge rings 910 and the edge ring 920 stay relatively the same as the top edge ring 910 is lifted. In some examples, the predetermined distance is greater than or equal to the maximum increase in height of the top edge ring 910 due to wear.
Referring now to FIG. 9C, a top edge ring 950 has an inverted “U”-shape and includes an annular body 954, a radially inner leg 952 and a radially outer leg 956. In some examples, the radially outer leg 956 is P times thicker in a radial direction than the radially inner leg 952. The top edge ring 950 includes a radial recess 957 located on a downwardly facing surface of the radially outer leg 956. Additional radial recesses 957 are provided for each of the lift pins. In some examples, three lift pins are arranged around the edge ring and spaced at 120° interval. The radial recess 957 includes an angled lower surface 958 that slopes at an acute angle downwardly and radially outwardly. The radial recess 957 and the angled lower surface 958 are biased by the lift pin and help to center the top edge ring 950 relative to the baseplate 130 and the substrate 128.
In FIGS. 9C1 and 9C2, additional views of the radial recess are shown. In FIG. 9C1, a bottom view of a portion of the edge ring is shown. In FIG. 9C2, a cross-sectional view taken along 9C2-9C2 in FIG. 9C1 is shown. In some examples, surfaces 990 and 992 have a radius. In some examples, the angle Θ is in a range from 75° to 105° (e.g. 90°).
An edge ring 960 is generally “U”-shaped and includes an annular body 966, a radially inner leg 962 and a radially outer leg 964. The radially inner leg 952 of the top edge ring 950 is located between the radially inner leg 962 and the radially outer leg 964 of the edge ring 960.
An edge ring 970 includes an annular recess 974 located on a radially inner and upper surface thereof. A radially inner portion 972 of the edge ring 970 is arranged adjacent to the baseplate 130 and the heating plate 132. The lift pin passes through a vertical bore in the radially inner portion 972 of the edge ring 970. The radially inner portion 972 of the edge ring 970 includes an annular recess 973 on a radially inner and upper surface thereof to provide clearance and/or support for a lower portion of the radially outer leg 964 of the edge ring 960. The radially inner portion 972 of the edge ring 970 further includes a projection 975 that extends downwardly from a lower and radially inner surface thereof.
In some examples, the baseplate 130 includes a conforming seal 971 that follows a stepped, or lower, radially outer surface of the baseplate 130. In some examples, the conforming seal 971 is made of a material such as ceramic and reduces arcing. A lower surface of the edge ring 970 includes a first annular recess 976 or step to accommodate the lift pin and a second annular recess 978 to accommodate the baseplate 130.
In some examples, the base height is 3.5 mm. In some examples, the edge rings 950 and 980 are made of conductive material such as silicon or silicon carbide, although other materials can be used. In other examples, the edge rings 970 and 986 are made of quartz although other materials can be used.
Referring now to FIG. 9D, an example of a variation of the edge ring system in FIG. 9C is shown. An edge ring 980 is located below the top edge ring 950. The edge ring 980 is generally “L”-shaped and includes a radially-inwardly projecting leg 984 and a vertical leg 982. The vertical leg 982 is located between the radially inner leg 952 and the radially outer leg 956 of the top edge ring 950. An edge ring 986 is located below the substrate 128 and radially outside of the heating plate 132. The edge ring 986 is generally rectangular-shaped with an annular recess 988 or step located on a lower and outer surface thereof to receive the radially-inwardly projecting leg 984.
In some examples, a base height (e.g. a top surface of the top edge ring 950 to the top surface of the baseplate 130) is 3.5 mm. In some examples, the edge rings 950, 980, 986, and 970 are made of quartz, silicon carbide, silicon (or silicon carbide) and quartz, respectively, although other materials can be used.
Referring now to FIG. 9E, other example variations of the edge ring system are shown. In FIG. 9E, the radially outer leg 956 of the top edge ring 950′ extends less radially outwardly and is covered by an edge ring 990. The edge ring 990 has an “L”-shaped cross-section and includes a radially-inwardly projecting leg 992 and a downwardly projecting leg 994 connected to a radially outer portion of the radially-inwardly projecting leg 992. In some examples, the top edge ring 950 of FIG. 9D may be too large to fit through the substrate port into the processing chamber. Splitting the top edge ring 950 into two parts as shown at 950′ and 990 in FIG. 9E allows the edge ring 990 to be removed and replaced through the substrate port (without breaking vacuum when a vacuum transfer module is used). In some situations, the edge ring 950 in FIG. 9D may be too thick and/or too heavy to be moved by the robot arm. With using a thinner and lighter top edge ring 990 in combination with the edge ring 950″, the edge ring 990 can be removed when the edge ring 990 is worn since the edge ring 990 is less thick and lighter.
In some examples, a base height (e.g. a top surface of the top edge ring 950 to the top surface of the baseplate 130) is 3.5 mm. In some examples, the edge rings 990, 950, and 980 are made of silicon carbide, the edge ring 986 is made of silicon and the edge ring 970 is made of quartz, although other materials can be used.
Referring now to FIG. 9F, an edge ring 950″ that is similar to the top edge ring 950 of FIG. 9C with tighter tolerances is shown. In some examples, gaps between the edge rings are greater than 0.01 mm and less than or equal to 0.5 mm, 0.25 mm, 0.2 mm, or 0.1 mm. In other examples, a gap between the top edge ring and the substrate is greater than 100 μm and less than 500 μm, 400 μm, or 350 μm. In some examples, a base height (e.g. a top surface of the top edge ring 950′ to the top surface of the baseplate 130) is 5.5 mm. In some examples, the edge rings 950′, 980, and 970 are made of quartz, although other materials can be used.
Referring now to FIG. 9G, an outer edge ring 995 defines an annular recess 974 or step on a top surface thereof and a projection 996 that extends radially inwardly from the outer edge ring 995 adjacent to the annular recess 974. An edge ring 997 has a generally rectangular cross-section and includes an annular recess 998 or step located on a radially outer and upper surface to receive the projection 996. The edge ring 997 includes a projection 999 extending upwardly from an upper, radially inner surface of the edge ring 997 adjacent to a radially outer surface of the heating plate 132. In some examples, the edge rings 950″ is made of silicon (or quartz, or silicon carbide), the edge ring 980 is made of silicon or silicon carbide, the edge ring 997 is made of ceramic, aluminum or quartz, and the edge ring 970 is made of quartz, although other materials can be used. The projection 996 of the edge ring 970 and the annular recess 998 of the edge ring 997 define a serpentine path to reduce plasma arcing.
Referring now to FIGS. 10A and 10B, instead of relying upon the capacitance of conductive edge ring, the edge rings can be made of dielectric material and can include embedded conductors without external connectors thereto. For example, in FIGS. 10A and 10B, the edge ring 920 in FIGS. 9A and 9B can be made of dielectric material and can include embedded conductors 1008 that are made of metal. The top edge ring 910 is made of conductive material.
The embedded conductors 1008 include vertical conductive portions 1010 and horizontal conductive portions 1020. The embedded conductors 1008 are arranged to provide relatively constant capacitance as the top edge ring 910 is raised due to wear as shown in FIG. 10B. In the example in FIGS. 10A and 10B, the horizontal conductive portion 1020 provides coupling to the heating plate 132. As the top edge ring 910 is moved upwardly due to wear, the horizontal conductive portion 1020 maintains coupling to the heating plate 132. As a result, the capacitance of the delivery components remains approximately the same.
Referring now to FIGS. 11A and 11B, the edge ring 840 is made of dielectric material (instead of conductive material as in FIGS. 8A and 8B above) and includes an embedded conductor 1108 without external connection thereto. The top edge ring 810 is made of conducting material or dielectric material. The embedded conductor 1108 includes an upper horizontal conductor 1110 arranged near and parallel to a lower surface of the top edge ring 810. The upper horizontal conductor 1110 is connected to a vertical conductor 1112 that extends near a middle of the middle edge ring 840. The vertical conductor 1112 connects to a horizontal conductor 1120 that extends radially inwardly and connects to a vertical conductor 1122. The vertical conductor 1122 is arranged near and extends along a radially inner surface of the edge ring 840 near the lower portion.
In FIG. 11B, as the edge ring 840 is raised to compensate for wear of the top edge ring 810, coupling between the vertical conductor 1110 and the top edge ring 810 remains relatively constant (and less than or equal to DA). Likewise, coupling between the vertical conductor 1122 and a conductive facing surface of the baseplate 130 remains relatively constant (and less than or equal to DA). In other locations, the embedded conductor has a gap distance that is greater than or equal to DB.
Referring now to FIGS. 11C to 11E, an arcuate portion of the edge ring 840 is shown. The edge ring 840 can be made of a plurality of ceramic green sheets that are stacked and sintered. Prior to sintering, vertical conductors or vias are created by cutting holes in adjacent ceramic green sheets and filling the holes with a conductive material such as a conductive paste. In some examples, tungsten paste is used. Horizontal conductors are formed by printing traces or conductive planes on the ceramic green sheets using conductive material. In some examples, the horizontal conductors are printed to overlap and contact the vertical conductors to provide connections therebetween.
In FIG. 11C, the vertical conductors 1112 or vias are shown connected to a conductive plane 1150 that defines the horizontal conductor 1110. In FIG. 11D, in locations where there are no horizontal conductors, the vertical conductors pass through the ceramic green sheets. In FIG. 11E, instead of using the conductive plane shown in FIG. 11D, a plurality of traces 1160 can be used to implement the horizontal conductors 1110 instead of the conductive plane 1150.
Referring now to FIGS. 12A and 12B, the top edge ring 710 of FIG. 7 can be made of dielectric instead of conductive material. The top edge ring 710 includes an embedded conductor 1208 without external connections thereto. The embedded conductor 1208 includes a horizontal conductor 1210 arranged parallel to a top surface of the top edge ring 710. The horizontal conductor 1210 is spaced a predetermined distance from the top surface to allow wear of the dielectric material without exposing the horizontal conductor 1210. A vertical conductor 1220 extends vertically near a middle portion of the top edge ring 710. The vertical conductor 1220 connects to the horizontal conductor 1210 and to a horizontal conductor 1224 arranged parallel to a bottom surface of the top edge ring 710. The horizontal conductor 1224 allows capacitive coupling to the lift pin 754. The lift pin 754 is made of conductive material. As can be seen in FIG. 11B, coupling between the lift pin 754 and the horizontal conductor 1224 remains constant as the top edge ring 710 is lifted.
Referring now to FIGS. 13A and 13B, the edge ring 840 is made of a dielectric material or conductive material (as defined herein) and includes one or more doped regions that are more conductive than the remaining regions that are undoped. The top edge ring 810 is made of conductive material or dielectric material.
In this example, a top surface 1320 of the edge ring 840 lying below the top edge ring 810 is doped to a predetermined depth to render the material more conductive than undoped material. Likewise, a radially inner surface 1322 of the edge ring 840 is also doped to a predetermined depth to render the dielectric material more conductive from the top surface 1320 to a bottom edge of the lower surface 849. The top surface 1320 and the radially inner surface 1322 are electrically connected. While a single continuous doped region is shown, two or more doped regions may be used.
For example, the edge ring 840 may be made of silicon carbide that is doped with boron, aluminum or nitrogen to make selected portions thereof more conductive than undoped areas. In FIG. 13B, the conductive portions of the edge ring 840 provide uniform coupling to adjacent surfaces as the middle edge ring is raised due to wear of the top edge ring 810.
Referring now to FIG. 14A, a top edge ring 1410 is arranged above edge rings 1412, 1416, and 1420. The top edge ring 1410 has an inverted “U”-shape and includes an annular body 1434, a radially inner leg 1432 and a radially outer leg 1436. The annular body 1434 has a thickness t to allow enough material for stability of the edge ring during handling and sufficient material to allow a sufficient number of cycles prior to replacement due to erosion. In some examples, the thickness t is in a range from 0.5 mm to 10 mm, although other thicknesses can be used. In some examples, the thickness t is in a range from 0.5 mm to 5 mm, although other thicknesses can be used.
A top surface 1438 of the radially outer leg 1436 slopes linearly downwardly at 1438′ (to create an inclined surface) near a mid-portion of the top edge ring 1410 to a radially outer edge of the top edge ring 1410. The sloped portion 1438′ slopes linearly downwardly by a vertical distance d from the top surface 1438′. A horizontal distance h is provided from the radially outer edge of the “U” shape to a location where the top surface 1438 begins to slope downwardly. In some examples, depending on the thickness t, the horizontal distance h is in a range from 0 mm to 10 mm, although other horizontal distances can be used. In some examples, d is greater than or equal to t. In some examples, d is in a range from t to 3t. In some examples, d is less than or equal to t. In some examples, d is in a range from 0.25*t to t. The edge rings 1412 and 1416 have “L”-shaped cross-sections.
In some examples, the top surface 1438 has an overall thickness H. In some examples, the overall thickness H of the edge ring is in a range from 5 mm to 20 mm. In some examples, the distance d is greater than or equal to 5%, 10%, 20%, 30%, 40% or 50% of the height H. In some examples, the sloped portion 1438′ slopes linearly at an acute angle. In some examples, the sloped portion 1438′ slopes at an acute angle in a range from 20° to 70°.
Edge ring 1410 is generally taller than prior edge rings to allow for longer wear, and to accommodate the “U” shape. Due to wear, the edge ring may crack if there is not enough material between the “U” shape and the top surfaces 1438 and 1438′. As can be appreciated, removal of material in the radially outer sloped portion reduces the weight of the edge ring 1410, which reduces the load on the actuators. This allows the actuators to provide finer adjustments. A linear slope of the sloped portion 1438′ increases the amount of material that can be removed without removing too much material between the “U” shape groove and the top surfaces 1438 and 1438′ as compared to stepped designs. In some examples, the distance d is greater than thickness t of the annular body 1434 to increase the amount of material that is removed. In some examples, the horizontal distance h is less than the thickness t of the annular body 1434 to increase the amount of material removed.
The edge ring 1412 is located radially outside of the edge ring 1416 and below the top edge ring 1410. The edge ring 1412 includes an upwardly projecting leg 1448 and a leg 1446 extending radially inwardly from the upwardly projecting leg 1448. The edge ring 1416 is located adjacent to the heating plate 132, radially inside of the edge ring 1412 and below the substrate 128. The edge ring 1416 includes an upwardly projecting leg 1440 and a leg 1442 extending radially outwardly from the upwardly projecting leg 1440.
The edge ring 1420 includes a radially outer portion 1452 and a radially inner portion 1454 that extends radially inwardly from a lower portion of the radially outer portion 1452. A step surface 1455 supports the radially outer leg 1436 of the top edge ring 1410 when lowered. An upward projection 1456 extends upwardly from an inner, upper surface of the radially inner portion 1454. A lift pin 1460 move reciprocally in a vertical bore in the radially inner portion 1454 of the edge ring 1420 to raise and lower the edge ring 1410.
Referring now to FIG. 14B, the top edge ring 1410 includes an alternate upper surface profile. A sloped portion 1464′ of a top surface of the edge ring 1410 slopes downwardly in a radially outer direction. The sloped portion 1464′ transitions to a surface 1466, which is generally parallel to a plane including the substrate 128. Removal of material of the edge ring in the sloped portion 1464′ reduces the weight of the top edge ring 1410. Weight reduction can be performed to allow use with lift actuators having lower lifting capacity.
Referring now to FIG. 14C, a radially inner edge 1470 of the top edge ring 1410 defines a gap with respect to a radially outer surface of the upwardly projecting leg 1440 of the edge ring 1416. The gap is increased relative to the edge ring systems in FIGS. 14A and 14B.
Referring now to FIG. 15, an edge ring system includes a top edge ring 1510, an outer edge ring 1520 and an edge ring 1530. The edge ring 1530 is located below the top edge ring 1510 and radially inside of the outer edge ring 1520. The top edge ring 1510 includes a generally rectangular body 1514 and a radially inwardly projecting leg 1516 extending from a radially inner and upper surface of the top edge ring 1510. The edge ring 1530 is generally rectangular and includes an annular recess 1534 located on an upper and radially inner surface thereof. The substrate 128 is received in the annular recess 1534. The outer edge ring 1520 includes a radially outer portion 1522 and an inner portion 1524 that extends radially inwardly from a middle portion of the radially outer portion 1522. A lift pin 1560 moves reciprocally in a vertical bore in the inner portion 1524 of the outer edge ring 1520. A projection 1526 extends upwardly from a radially inner and upper surface of the outer edge ring 1520. The generally rectangular body 1514 of the top edge ring 1510 is received on an upper surface 1555 of the outer edge ring 1520 between the projection 1526 and the radially outer portion 1522.
In some examples, a top surface 1518 of the edge ring 1510 has a height H before a sloped portion 1518′. The sloped portion 1518′ slopes downwardly by a distance d from the top surface 1518 to the radially outer edge of the top edge ring 1510. In some examples, the distance d is greater than or equal to 5%, 10%, 20%, 30%, 40% or 50% of the height H. In some examples, the sloped portion 1518′ slopes downwardly at an acute angle. In some examples, the sloped portion 1518′ slopes at an acute angle in a range from 20° to 70°. As can be appreciated, the material removed to create the sloped portion 1518′ helps to reduce the weight of the edge ring 1510, which reduces the load on the actuators and increases reliability.
In some examples, the heating plate 132 has a cylindrical center portion 1577 and a projecting portion 1579 that extends radially outwardly from a bottom portion of the cylindrical center portion. In some examples, the heating plate 132 does not include RF electrodes. In other examples, the RF electrodes located in the heating plate 132 in a vicinity of the edge ring are removed. For example, RF electrodes are removed in an area 1580 of the heating plate located beneath the edge ring 1530.
Referring now to FIG. 16A to 16C, a moveable edge ring system 1600 is shown. In FIG. 16A, the moveable edge ring system 1600 includes a top edge ring 1610 including an annular body 1612. A radially outer leg of the top edge ring 1610 projects downwardly from a radially outer surface of the annular body 1612. A radially inner leg 1616 projects downwardly from a radially inner surface of the annular body 1612. An inwardly projecting leg 1618 extends radially inwardly from a lower end of the radially inner leg 1616. The inwardly projecting leg 1618 extends below a radially outer edge of the substrate 128. In some examples, the heating layer 132 includes an annular recess 1619 and the inwardly projecting leg 1618 is received in the annular recess 1619 on an upper surface thereof between the substrate 128 and the annular recess 1619.
An edge ring 1620 includes an annular body 1622. A radially outwardly projecting leg 1624 extends from an upper and radially outer surface of the annular body 1622. A radially inwardly projecting leg 1528 extends radially inwardly from a radially inner and lower surface of the annular body 1622. The edge ring 1620 is located radially outside of the top edge ring 1610.
An edge ring 1630 is located radially inside of the edge ring 1620 and below the top edge ring 1610. The edge ring 1630 includes an annular body 1632. A radially inwardly projecting leg 1634 extends radially inwardly from an upper and radially inner surface of the annular body 1632. As will be described further below in conjunctions with FIGS. 17-22, the edge ring 1632 can include spacers 1633 such as shims, pins or projections to maintain spacing between the edge ring 1630 and the edge rings 1620 and/or 1640. As also described further below, insulating coatings may be used.
An edge ring 1640 is located below the edge ring 1620 and radially outside of a lower portion of the edge ring 1630. The edge ring 1640 includes an annular body 1642, a radially downwardly projecting leg 1644 extends from a radially outer and lower surface of the annular body 1642. An inwardly projecting leg 1646 extends radially inwardly from a middle and inner portion of the annular body 1642. The inwardly projecting leg 1646 includes a vertical bore 1647 that receives a lift pin 1648. The edge ring 1640 includes an annual recess 1650 and a projection 1652 that define a vertical bore in a lower surface of the edge ring 1640 to receive a guide sleeve 1660 arranged in a vertical bore 1664 in the baseplate 126. The edge ring 1640 includes an annular recess 1654 on a lower and radially inner surface thereof to provide clearance for a radially outer edge of the baseplate 126.
When biased by the lift pin 1648 against a lower surface of the edge ring 1610, the edge ring 1630 defines a first vertical gap 1670 between the radially inner leg 1634 and an upper surface of the heating layer 132. The edge ring 1630 also defines a second vertical gap 1672 between a lower surface of the edge ring 1630 and an upper surface of the radially inwardly projecting leg 1646.
In FIG. 16B, when the lift pin 1648 is fully lowered, the edge ring 1630 defines a third vertical gap 1680 between a lower surface of the edge ring 1610 and an upper surface of the edge ring 1630. The lower surface of the edge ring 1630 rests on the upper surface of the radially inwardly projecting leg 1646. During operation, the edge ring 1630 can be arranged in an abutting relationship with the edge ring 1610 by raising the lift pin 1648 or in a spaced relationship with the edge ring 1610 by lowering the lift pin 1648 and the edge ring 1630.
When the edge ring 1610 is worn due to exposure to the plasma, the substrate 128 is removed and the lift pin 1648 lifts the edge ring 1630 and the edge ring 1610 upwardly as shown in FIG. 16C. The edge ring 1610 is removed from the processing chamber through the substrate port using a robot arm (such as a vacuum transfer module robot arm). Another one of the edge rings 1610 is delivered (through the substrate port using the robot arm) onto the edge ring 1630 and the lift pin 1648 is lowered. In some examples, the top ring 1610 is made of either conductive or dielectric material, the ring 1630 is made of either conductive material or dielectric material with embedded electrodes, and the ring 1620 and 1640 are made of dielectric material.
Referring ow to FIG. 16D, the edge ring 1640 of FIGS. 16A-16C can be split into two concentric rings. An inner ring 1680 includes an annular body 1682 and an annular recess 1684 located on a lower and radially inner surface (similar to the annular recess 1650 in FIGS. 16A-16C). The inner ring 1680 is made of a conductive material to enhance capacitive coupling with the edge ring 1630. This arrangement allows more RF to be transmitted between the baseplate 126 and the edge ring 1630.
An outer ring 1690 includes an annular body 1692 that is made of a dielectric material. The annular body 1692 is located radially outside of the inner ring 1680. A radially inner surface 1694 of the outer ring 1690 lies adjacent to a radially outer surface 1686 of the inner ring 1680.
Referring now to FIGS. 17 and 18, many of the foregoing examples include an upper ring that is exposed to plasma and a lower ring located below and shielded from direct plasma by the upper ring. For example, a cross-section of a portion of an edge ring system 1700 that is designed to have capacitance coupling is shown in FIG. 17. A lower portion of an upper ring 1710 is located radially outside of a lower portion of a lower ring 1720.
To maintain control of the plasma sheath at low bias frequencies, the value of the coupling capacitance C should remain fixed and relatively constant as the upper ring 1710 is exposed to plasma, experiences erosion and has its height raised. Furthermore, there may be a significant difference in temperature between the upper ring 1710 and the lower ring 1720. For example, the temperature difference between the upper ring 1710 and the lower ring 1720 may be in a range from 0° C. to 200° C. (e.g. 100° C.) during plasma processing. In some examples, as the lower ring 1720 expands when heated and contracts when cooled, the lower ring 1720 (or the upper ring 1710) may move or walk in a direction parallel to the substrate in a direction towards one side of the upper ring 1710 effectively reducing the gap in some radial directions and increasing the gap in other radial directions.
Assuming that C is the capacitance between the upper ring 1710 and the lower ring 1720, as the lower ring 1720 moves off center (closer to the upper ring 1710 in some radial directions and further from the upper ring 1710 in other radial directions), the capacitance increases because capacitance is a non-linear function of the gap. More particularly, the capacitance Cshifted=S(s)*Ccentered where s′=d/(R2−R1), where 0<s′<1 and where R2 is the inner diameter of the upper ring 1710 and R1 is the outer diameter of the lower ring 1720. In FIG. 18, the relative increase in capacitance is shown as a function of shift percentage (%) of a nominal gap. As can be appreciated, the capacitance is affected when the shift percentage is greater than about 35-40% of the nominal gap.
Systems and methods according to the present disclosure use a spacer such as a shim, pin or projection on the upper ring or the lower ring to limit movement of the upper ring 1710 relative to the lower ring 1720 during heating and cooling experienced during plasma processing. In some examples, the movement is limited to less than or equal to 20%, 30% or 40% of the nominal gap to limit the effect of the relative movement on the capacitance of the edge ring system.
Referring now to FIGS. 19-22, various ways of limiting movement of the upper ring relative to the lower ring of an edge ring system are shown. In FIG. 19, an edge ring system 1900 includes an upper ring 1910 including inner and outer portions 1910-1 and 1910-2 located adjacent to radially inner and outer surfaces of a lower ring 1920, respectively. In FIGS. 20-22, various ways for limiting movement of the upper ring 1910 relative to the lower ring 1920 are shown.
In FIG. 20, the lower ring 1920 includes a slot 1938 located on a radially outer surface thereof. The slot 1938 extends radially inwardly into the radially outer surface of the lower ring 1920. A shim 1934 is arranged in the slot 1938. In some examples, adhesive 1930 is used to retain the shim 1934 in the slot 1938. In some examples, the shim 1934 has rectangular plan, radial and side cross-sections, although other shapes can be used. In some examples, the shim 1934 has a thickness in a radial direction that is greater than or equal to a depth of the slot 1938. In some examples, the shim 1934 extends radially outwardly from the lower ring 1920 to a distance sufficient to limit movement (given the number of shims that are used).
In FIG. 21, the lower ring 1920 includes a slot 1948 located on a radially outer surface thereof. The slot 1948 extends radially inwardly. A pin 1950 is arranged in the slot 1948. In some examples, adhesive 1930 is used to retain the pin 1950 in the slot 1948. In some examples, the pin 1950 has cylindrical shape, although other shapes can be used. In some examples, the pin 1950 has a height in a radial direction that is greater than or equal to a depth of the slot 1948. In some examples, the pin 1950 extends radially from the lower ring 1920 to a distance sufficient to limit movement (given the number of pins that are used).
In FIGS. 22A and 22B, the lower ring 1920 includes a projection 1960 formed on a radially outer surface thereof. In some examples, the projection 1960 extends in a vertical direction partially or fully along the vertical thickness of the radial outer surface. In FIG. 22B, the projection 1960 includes a flat surface 1964 extending from a radially outer surface 1962 of the lower edge ring 1920, which is easier to machine and to inspect dimensions as compared to arcuate profiles. In other words in some examples, the edge ring is initially formed slightly wider without the projections 1960 and then a radially outer surface is machined or removed in areas between adjacent projections to form the projections 1960. In other examples, the projections 1960 include arcuate or convex profiles in plan view to reduce surface area in contact with the radially inner facing surface of the top edge ring and reduce friction when performing height adjustment or replacing the top edge ring without breaking vacuum.
In some examples, the projections 1960 are coated with a coating material 1964. In some examples, the coating material 1964 is relatively conformal and is made of an insulating material. In some examples, the coating is selected from a group consisting of polytetrafluoroethylene (PTFE), perfluoroalkoxy polymer (PFA), or aluminum oxide, yttrium oxide, or yttrium fluoride deposited using atomic layer deposition. The coating material 1964 has an insulating function that prevents short circuits and reduces erosion. The coating material 1964 also ensures a minimum gap between the lower ring 1920 and the upper ring 1910 to prevent short circuits. In some examples, the projection 1960 extends radially outwardly from a radially outer surface of the lower ring 1920 to a distance sufficient to limit movement (given the number of projections that are used).
In some examples, the lower ring 1920 includes 3 to 8 spacers (shims, projections or projections) arranged with uniform spacing (e.g. 120° spacing for 3, 72° spacing for 5, 45° spacing for 8 (or 360°/N)) around an outer periphery of the lower ring 1920. As can be appreciated, the spacers are not generally configured to completely constrain relative movement of upper and lower rings. The gap helps reduce binding during height adjustment and/or replacement. Therefore, some relative movement is still desirable and undesirable movement (which may alter the effective coupling capacitance) may still occur with 3 shims. In some examples, the lower ring 1920 includes 5 spacers arranged around an outer periphery of the lower ring 1920 to further constrain movement. Depending upon the particular configuration, additional spacers such as 6, 7 or 8 provide diminishing returns with respect to controlling the effective capacitance and increase cost.
While the spacers (e.g. shims, projections or projections) are shown arranged on an outer surface of the lower ring 1920, the spacers can be arranged on an inner surface of the lower ring 1920 and/or one or both of the inner surfaces of the upper ring 1910. In addition, the spacers and/or insulating coating can be arranged on any of the preceding examples (e.g. in FIGS. 1 to 22) on one or both of the radially facing surfaces of edge rings that are intended to capacitively couple.
In some examples, the spacers extend in a radially outward direction in a range from 50 μm to 250 μm from a radially outer surface of the edge ring. In some examples, the spacers extend in a radially outward direction in a range from 50 μm to 250 μm from a radially outer surface of the edge ring.
The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.
Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”
In some implementations, a controller is part of a system, which may be part of the above-described examples. Such systems can comprise semiconductor processing equipment, including a processing tool or tools, chamber or chambers, a platform or platforms for processing, and/or specific processing components (a wafer pedestal, a gas flow system, etc.). These systems may be integrated with electronics for controlling their operation before, during, and after processing of a semiconductor wafer or substrate. The electronics may be referred to as the “controller,” which may control various components or subparts of the system or systems. The controller, depending on the processing requirements and/or the type of system, may be programmed to control any of the processes disclosed herein, including the delivery of processing gases, temperature settings (e.g., heating and/or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, positional and operation settings, wafer transfers into and out of a tool and other transfer tools and/or load locks connected to or interfaced with a specific system.
Broadly speaking, the controller may be defined as electronics having various integrated circuits, logic, memory, and/or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and/or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files), defining operational parameters for carrying out a particular process on or for a semiconductor wafer or to a system. The operational parameters may, in some embodiments, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and/or dies of a wafer.
The controller, in some implementations, may be a part of or coupled to a computer that is integrated with the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e.g. a server) can provide process recipes to a system over a network, which may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and/or settings, which are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control. Thus as described above, the controller may be distributed, such as by comprising one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.
Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing systems that may be associated or used in the fabrication and/or manufacturing of semiconductor wafers.
As noted above, depending on the process step or steps to be performed by the tool, the controller might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and/or load ports in a semiconductor manufacturing factory.

Claims

What is claimed is:

1. An edge ring for a plasma processing system, comprising:

an annular body;

a radially inner leg extending from the annular body;

a radially outer leg extending from the annular body,

wherein a first portion of an upper surface of the annular body is parallel to a plane including a substrate, and

wherein a second portion of the upper surface of the annular body slopes downward at an angle from the first portion.

2. The edge ring of claim 1, wherein the first portion of the upper surface is located radially inward of the second portion of the upper surface.

3. The edge ring of claim 2, wherein a third portion of the upper surface is parallel to the plane including the substrate and is located radially outward of the second portion of the upper surface.

4. The edge ring of claim 1, wherein the edge ring has an inverted “U” shape.

5. The edge ring of claim 4, wherein the second portion of the upper surface begins to slope downward at a horizontal distance h from a radially outer edge of the inverted “U” shape, and wherein the horizontal distance h is in a range from 0 mm to 10 mm.

6. The edge ring of claim 1, wherein a thickness t of the annular body is in a range from 0.5 mm to 10 mm.

7. The edge ring of claim 6, wherein the second portion of the upper surface slopes downward by a vertical distance of d that is greater than or equal to 20% of a height of an overall thickness of the edge ring.

8. The edge ring of claim 6, wherein the second portion of the upper surface slopes downward by a vertical distance of d, and wherein d is greater than or equal to t.

9. The edge ring of claim 8, wherein d is in a range from t to 3t.

10. The edge ring of claim 1, wherein second portion of the upper surface slopes linearly at an acute angle.