Apparatus for reducing contamination in a plasma etching chamber

Abstract

Embodiments of process fitting components for use in a substrate support and a substrate support incorporating the embodiments are provided. In some embodiments, the substrate support may include: a body; a grounded housing formed of a conductive material disposed around the body; a lining formed of a conductive material disposed around the grounded housing, wherein the lining includes an upper lip extending inwardly towards the body; a metal fastener passing through the upper lip to couple the lining to the grounded housing; and a first insulator ring disposed atop the upper lip of the lining and covering the metal fastener.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to substrate processing equipment, and more particularly to substrate supports used in substrate processing equipment. Background Art

[0002] Metal fasteners are commonly used to connect various structures that make up a substrate support within a processing chamber, such as a plasma processing chamber. The inventors have found that metal fasteners (such as titanium (Ti) screws) near the conductive structures of the substrate support may cause Ti contamination within the processing chamber.

[0003] Thus, the inventors have provided an improved substrate support that can reduce or eliminate metal contamination from metal fasteners. Summary of the Invention

[0004] Embodiments of process fitting components for use in a substrate support and a substrate support incorporating the embodiments are provided herein. In some embodiments, the substrate support includes: a body; a grounded housing formed of a conductive material disposed around the body; and a liner formed of a conductive material disposed around the grounded housing. The liner includes an upper lip extending inwardly towards the body. A metal fastener is disposed through the upper lip to couple the liner to the grounded housing. A first insulator ring is disposed on top of the upper lip of the liner and covers the metal fastener.

[0005] In some embodiments, a substrate support includes: a body; a shaft extending downward from the body; a conductive liner disposed around the body, wherein the conductive liner has an upper lip extending inwardly that covers an upper surface of a grounded housing; a fastener disposed through the upper lip to couple the conductive liner to the grounded housing; a first insulator ring disposed on top of the upper lip of the liner and covering the metal fastener; and a second insulator ring circumscribing the body, wherein the second insulator ring is disposed within a notched upper inner periphery of the first insulator ring.

[0006] In some embodiments, a substrate support includes: a body having a cylindrical shape and a notched upper peripheral edge defined by a first surface perpendicular to the sidewall of the body; a conductive housing having a top surface disposed around the body; a conductive lining disposed around the conductive housing and having an inner lip extending above the conductive housing; a plurality of fasteners passing through the conductive lining to couple the conductive lining to the conductive housing; a first insulator ring disposed on the top surface of the conductive lining and covering the plurality of fasteners; and a second insulator ring disposed between the first insulator ring and the body, wherein the second insulator ring is partially disposed within the notched upper peripheral edge of the body and extends outwardly towards the conductive lining.

[0007] Other and further embodiments of the present disclosure are described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The embodiments of the present disclosure outlined briefly above and discussed in more detail below may be understood by reference to the illustrative embodiments of the present disclosure depicted in the drawings. The drawings only show some embodiments of the present disclosure and are thus not considered to limit the scope of the present disclosure, as the present disclosure may permit other equivalent embodiments.

[0009] Figure 1 A schematic cross-sectional view of a plasma processing chamber used with a substrate support in accordance with some embodiments of the present disclosure is depicted.

[0010] Figure 2 Depicted in accordance with some embodiments of the present disclosure Figure 1 partial schematic side view of a substrate support.

[0011] Figure 3 Depicted in accordance with some embodiments of the present disclosure Figure 1 partial schematic side view of a substrate support.

[0012] For ease of understanding, the same reference numerals have been used as far as possible to denote the same elements common to the figures. The drawings are not necessarily to scale and may be simplified for clarity. Elements and features of one embodiment may be advantageously combined in other embodiments without further elaboration. DETAILED DESCRIPTION

[0013] Embodiments of process fitting components for a substrate support that can advantageously reduce or prevent metal contamination, such as titanium (Ti) contamination, in a process chamber are provided. Specifically, embodiments of the substrate support can include an insulator ring configured to cover one or more metal fasteners, thus preventing plasma in the processing chamber from contacting the one or more metal fasteners. Figure 1 A schematic cross-sectional view of a plasma processing chamber used with a substrate support in accordance with some embodiments of the present disclosure is depicted. Figure 2 Depicted in accordance with Figure 1 is a partial detailed schematic side view of some embodiments of a substrate support. Figure 3 Depicted in accordance with Figure 1 is a partial detailed schematic side view of some embodiments of a substrate support.

[0014] Figure 1 FIG. 14 is a schematic cross-sectional view of a chamber 100, such as a plasma processing chamber, in accordance with some embodiments of the present disclosure. In some embodiments, the plasma processing chamber is an etching processing chamber. However, other types of processing chambers can also be used or modified for use with the embodiments of the substrate support described herein. For example, the etching processing chamber and substrate support described herein can be operated at a temperature of about 50° C. to about 500° C. and at a power level between about 500 W and about 10 kW at a frequency of about 13 MHz to about 60 MHz.

[0015] Chamber 100 is a vacuum chamber suitably adapted to maintain a sub-atmospheric pressure within chamber interior volume 120 during high temperature or high power substrate processing. Chamber 100 includes a chamber body 106 covered by a lid 104, the chamber body 106 enclosing a processing volume 122 located in the upper half of the chamber interior volume 120. Chamber body 106 and lid 104 can be made of metal, such as aluminum. Chamber body 106 can be grounded via being coupled to ground 116. Lid 104 can be electrically floating or grounded.

[0016] A substrate support 124 is disposed within chamber interior volume 120 to support and hold a substrate 108 (e.g., such as a semiconductor substrate), or other such substrates that can be electrostatically held. Substrate support 124 generally can include a base 136 and a hollow support shaft 112 for supporting base 136. Hollow support shaft 112 provides a conduit, for example, for supplying process gas, fluid, coolant, power, etc. to base 136.

[0017] In some embodiments, the bellows assembly 110 is disposed around the hollow support shaft 112 and coupled between the base 136 and the bottom surface 126 of the chamber 100 to provide a flexible seal that allows the base 136 to move vertically while preventing loss of vacuum within the chamber 100. The bellows assembly 110 also includes a bellows 134 that contacts an O-ring 128 or other suitable sealing element that contacts the bottom surface 126 to help prevent loss of chamber vacuum.

[0018] The chamber 100 is coupled to a vacuum system 114 and is in fluid communication with the vacuum system 114, which includes a throttle valve (not shown) and a vacuum pump (not shown) for evacuating the chamber 100. The pressure inside the chamber 100 can be adjusted by adjusting the throttle valve and / or the vacuum pump. The chamber 100 is also coupled to a process gas supply 118 and is in fluid communication with the process gas supply 118, which can supply one or more process gases to the chamber 100 for processing a substrate disposed in the chamber 100.

[0019] In operation, the substrate 108 can enter the chamber 100 via an opening in the chamber body 106. The opening can be selectively sealed via a slit valve 132 or other device for selectively providing access through the opening to the interior of the chamber 100. Additionally, in operation, a plasma 102 can be generated within the chamber interior volume 120 to perform one or more processes. The plasma 102 can be generated by coupling power from a plasma power source (e.g., RF plasma power supply 130) to the process gas via one or more electrodes near or within the chamber interior volume 120 to ignite the process gas and generate the plasma 102.

[0020] Figure 2 Depicted is a partial detailed schematic side view of some embodiments of a substrate support in accordance with Figure 1 The substrate support 124 includes a body 208 having an upper surface 210 for supporting a dielectric member 224 configured to electrostatically hold a substrate 202 disposed thereon.

[0021] The body 208 can include a conductive material, such as aluminum (Al), etc. The body 208 has a stepped or notched upper peripheral edge 206. The upper peripheral edge 206 of the body 208 is defined by a first surface 214 perpendicular to the sidewall 211 of the body 208 and a stepped second surface 215 disposed between the first surface 214 and the upper surface 210 of the body 208.

[0022] The body 208 may include one or more heat transfer fluid conduits (not shown) disposed near the lower surface of the body 208. The heat transfer fluid conduits may be coupled to a heat transfer fluid source (not shown) to supply heat transfer fluid to all adjacent conduits. The heat transfer fluid may flow through the conduits to control the temperature and / or temperature distribution of the substrate support 124 during use.

[0023] In some embodiments, the dielectric member 224 is utilized to hold the substrate 202 via a DC voltage supplied to the electrode 204 by a DC power source (not shown). Examples of processing apparatuses that may advantageously benefit from the modifications of the embodiments according to the present disclosure include processing apparatuses such as plasma reactors, including but not limited to any processing apparatus line obtained from Applied Materials, Inc. of Santa Clara, California. The above list of processing apparatuses is merely illustrative, and other plasma reactors and non-plasma apparatuses (such as CVD reactors or other etching processing apparatuses) may also be suitably modified according to the present teachings.

[0024] The dielectric member 224 may further include a lip 225 that radially extends around the dielectric member 224 from the bottom portion of the dielectric member 224 (e.g., adjacent to the upper surface 209 of the body 208). The lip 225 may extend to the periphery of the upper surface 210 of the body 208 (e.g., to the radially inner edge of the upper peripheral edge 206 of the body 208). A bonding layer (not shown) may be disposed between the upper surface 210 of the body 208 and the lower surface of the dielectric member 224 to bond the body 208 to the dielectric member 224. When a bonding layer is used, the bonding layer does not completely extend to the periphery of the upper surface 210 of the body 208. Thus, a portion of the lip 225 is suspended rather than supported by the bonding layer.

[0025] Additional components of the substrate support 124 may include an insulator housing 270 that circumscribes the body 208. The insulator housing 270 may be made of at least one of ceramic, quartz, silicon, silicon carbide, etc. The insulator housing 270 electrically insulates the body 208 from the grounded housing 246. The grounded housing 246 circumscribes the insulator housing 270. A liner 254 may circumscribe the grounded housing 246. A gap 276 may exist between the liner 254 and the grounded housing 246. The liner 254 is made of a conductive material. The liner 245 includes a lip 256 that axially extends inwardly toward the center of the substrate support 124. In some embodiments, the lip 256 is placed on the top surface 274 of the grounded housing 246. In some embodiments, the lip 256 extends inwardly to abut against the outer sidewall 258 of the insulator housing 270.

[0026] The lip edge 256 includes one or more holes 260 disposed through the lip edge. Each hole 260 disposed along the lip edge 256 can be of any suitable shape for receiving a corresponding fastener 262 disposed therethrough. For example, as Figure 2 shown, the hole 260 can include a countersink for allowing the head of each fastener 262 (e.g., when the fastener is a bolt, screw, etc.) to recess below the upper surface 268 of the lip edge 256. The grounded housing 246 includes one or more openings 272 corresponding to the holes 260. Each opening 272 can be of any suitable shape for receiving a corresponding fastener 262 disposed within the opening 272. In some embodiments, the opening 272 can be threaded to mate with the corresponding threads of the fastener 262.

[0027] The fastener 262 is disposed through the hole 260 to couple the liner 254 to the grounded housing 246 via the opening 272. Each fastener can be a screw, bolt, clamp, etc. In some embodiments, the fastener is a screw. Each fastener can include a metal such as titanium (Ti), steel alloy, etc. In some embodiments, the fastener includes titanium (Ti). In some embodiments, washers (not shown) can be disposed around each fastener 262. The washers can include the same material as the fastener 262. In some embodiments, the washers are titanium (Ti).

[0028] The substrate support 124 further includes a first insulator ring 230 disposed around the body 208 and on top of the lip edge 256 of the liner 254. The first insulator ring 230 is sized to cover one or more holes 260. The bottom surface 278 of the first insulator ring 230 forms a seal with the upper surface 268 of the liner 254 above the fastener 262. In use, the seal provided by the first insulator ring 230 advantageously limits or prevents exposure of the fastener 262 to the plasma 102 in the chamber 100. In some embodiments, the first insulator ring 230 circumscribes an insulator housing 270. The first insulator ring 230 can include quartz, alumina, anodized metal (such as anodized aluminum), aluminum coated with yttrium oxide, etc.

[0029] The substrate support 124 further includes a second insulator ring 240 disposed around the body 208. The second insulator ring 240 is disposed in the notched upper peripheral edge 206 of the body 208. In some embodiments, the second insulator ring 240 can be made of quartz, etc. The second insulator ring 240 includes a stepped inner wall 212 that mates with the stepped second surface 215 of the upper peripheral edge 206 to define a non-linear interface therebetween. The non-linear interface adds a curved path for the plasma and disrupts the line of sight from the plasma to any fasteners disposed through the body 208 below the second insulator ring 240.

[0030] The stepped inner sidewall 212 of the second insulator ring 240 may further include a first portion 218 that extends downward from the second insulator ring 240 toward the first surface 214 of the upper peripheral edge 206 of the body 208. The first portion 218 may have a length 220 between about 0.02 inches and 1.00 inches. The stepped inner sidewall 212 may further include a second portion 222 that extends laterally from the second insulator ring 240 along the stepped second surface 215 of the upper peripheral edge 206 of the body 208. The second portion 222 may have a length between about 0.02 inches and 1.00 inches.

[0031] The second insulator ring 240 may include a ledge 248 disposed around the upper inner edge of the second insulator ring 240. The top surface of the ledge 248 may be set flush with or above the lip 225 of the dielectric member 224. The insert ring 216 may be disposed on the ledge 248 of the second insulator ring 240. The insert ring 216 may be made of silicon (Si) or the like. The inner portion 226 of the insert ring 216 may extend axially inward toward the center of the substrate support 124 and be placed on top of the lip 225 of the dielectric member 224. A gap 242 may exist between the inner portion 226 of the insert ring 216 and the dielectric member 224.

[0032] The insert ring 216 may further include a ledge 244 disposed around the upper inner edge of the insert ring 216. The peripheral edge of the substrate 108 may extend into the ledge 244 of the insert ring 216. However, the ledge 244 is generally configured such that the substrate 108 does not contact the insert ring 216 and is fully supported by the dielectric member 224.

[0033] Optionally, a top ring 250 is disposed on top of the top surface 252 of the second insulator ring 240. As Figure 2 depicted, the top ring may include a downward protrusion along the lower outer edge of the top ring 250. The top ring 250 may be made of silicon (Si) or the like. The top ring 250 may protect the first insulator ring 230 from deterioration or damage from plasma and / or from the process environment.

[0034] The first insulator ring 230 may include a first portion 280 and a second portion 282. In some embodiments, the first insulator ring 230 has an L-shaped cross-section. The first portion 280 is disposed between the lip 256 of the liner 254 and the second insulator ring 240. The first portion 280 has an inner diameter larger than the outer diameter of the insulator housing 270 such that the first insulator ring 230 can be disposed around the upper portion of the insulator housing 270. The first insulator ring 230 includes a notched upper inner periphery 286. The second insulator ring 240 is disposed in the notched upper inner periphery 286 of the first insulator ring 230 to form a non-linear interface therebetween. The non-linear interface adds a curved path for the plasma similar to that described above. The second portion 282 circumscribes a portion of the second insulator ring 240. For example, the second portion 282 of the first insulator ring 230 may be disposed in the notched lower outer periphery 284 of the second insulator ring 240. In some embodiments, as Figure 2 shown, the first insulator ring 230 has an outer diameter similar (e.g., substantially the same) to the outer diameter of the second insulator ring 240. In some embodiments, the first insulator ring 230 has an outer diameter similar (e.g., substantially the same) to the outer diameter of the second insulator ring 240 such that when the first insulator ring 230 is disposed in the notched lower outer periphery 284 of the second insulator ring 240, the outermost wall of the first insulator ring 230 is substantially vertically aligned (e.g., along a substantially common virtual cylinder) with the outermost wall of the second insulator ring 240.

[0035] Figure 3 Depicts a partial detailed schematic side view of a Figure 1 substrate support according to some embodiments of the present disclosure text. Unless explicitly stated to the contrary in the following discussion, embodiments consistent with Figure 3 may be the same as those discussed above with respect to Figure 1 and Figure 2 . In some embodiments, the first insulator ring 330 has an L-shaped cross-section. In some embodiments, as Figure 3 shown, the first insulator ring 330 has an outer diameter larger than the outer diameter of the second insulator ring 340. The first insulator ring 330 includes a first portion 310 (e.g., an annular base) and a second portion 320 (e.g., a lip extending vertically upward from the annular base). The first portion 310 is disposed between the second insulator ring 340 and the lip 256 of the liner 254. Thus, as Figure 3 depicted, the inner diameter of the first portion 310 is smaller than the outer diameter of the second insulator ring 340 such that the radially outer portion of the second insulator ring 340 overlaps with the radially inner portion of the first portion 310.

[0036] The second portion 320 circumscribes the second insulator ring 340. Thus, asFigure 3 As depicted, the inner diameter of the second portion 320 is greater than the outer diameter of the second insulator ring 340, such that the radially outer portion of the second insulator ring 340 is disposed radially inwardly from the radially inner portion of the second portion 320.

[0037] In some embodiments, the second portion 320 extends close to the top ring 250. In some embodiments, the second portion 320 extends close to the top ring 250 but does not contact the top ring 250, thus defining a small gap between the upper surface of the second portion 320 and the bottom surface of the top ring 250.

[0038] In some embodiments, and as Figure 2 and Figure 3 depicted, the first insulator ring 230 does not contact the second insulator ring 240, and a narrow gap is defined between the opposing surfaces of the first insulator ring 230 and the second insulator ring 240. In some embodiments, and as Figure 2 and Figure 3 depicted, the first insulator ring 230 contacts only the lip 256 of the liner 254, and optionally, the upper portion of the fastener 262 (if not countersunk) disposed through the lip 256.

[0039] Figure 2 and Figure 3 The configurations of the first insulator ring 230 and the second insulator ring 240 in advantageously provide the same top - down process view as embodiments that do not include the first insulator ring 230, thus maintaining process integrity when modifying existing process fittings to accommodate the first insulator ring 230 and the second insulator ring 240. In other words, from a top - down view within the processing chamber, the first insulator ring 230 is hidden from view, and the plasma advantageously does not "see" the first insulator ring 230. Thus, contamination in the chamber can be reduced without any or with minimal impact on the process results on the substrate. In embodiments consistent with Figure 2 during a process that does not include the top ring 250, the first insulator ring 230 is additionally advantageously hidden from view, thus providing additional processing flexibility.

[0040] In some embodiments, and as Figure 2 and Figure 3 depicted, other components of the substrate support 124 discussed above can include small gaps between opposing non - sealed interfaces. For example, a small gap can be defined between the body 208 and the insulator housing 270, between the first insulator ring 230 and the second insulator ring 240, etc.

[0041] Therefore, embodiments of the substrate support 124 with reduced metal contamination have been provided herein. Covering the metal fasteners with an insulating material advantageously reduces or prevents exposure of the metal fasteners between the conductive components of the substrate support 124 to the plasma in the processing chamber.

[0042] Although the foregoing relates to embodiments of the present disclosure, other and additional embodiments of the present disclosure may be designed without departing from the basic scope of the present disclosure.

Claims

1. A substrate support, comprising: main body; a ground shell formed of a conductive material disposed around the body; a liner formed of a conductive material disposed about the grounded shell, wherein the liner includes an upper lip extending inwardly toward the body; a metal fastener disposed through the upper lip and coupling the liner to the grounded shell; a first insulator ring disposed atop the upper lip of the liner and covering the metal fastener; as well as A second insulator ring is disposed between the first insulator ring and the main body, wherein an outer diameter of the first insulator ring is the same as an outer diameter of the second insulator ring.

2. The substrate support of claim 1, wherein a top ring is disposed on an upper surface of the second insulator ring.

3. The substrate support of claim 1 , wherein the second insulator ring is disposed within the notched upper inner periphery of the first insulator ring. The substrate support of claim 1 , wherein the second insulator ring comprises quartz.

5. The substrate support of any one of claims 1 to 4, wherein the first insulator ring comprises at least one of quartz, alumina, anodized aluminum, or aluminum coated with yttrium oxide.

6. The substrate support of any one of claims 1 to 4, wherein the first insulator ring has an L-shaped cross-section.

7. The substrate support of any one of claims 1 to 4, further comprising an insulator housing disposed between the grounded housing and the main body, wherein the insulator housing electrically insulates the grounded housing from the main body.

8. The substrate support of any one of claims 1 to 4, wherein the metal fastener comprises a screw.

9. The substrate support of any one of claims 1 to 4, wherein the first insulator ring comprises a first portion and a second portion, and the second portion is disposed in a notched lower outer periphery of the second insulator ring.

10. The substrate support of any one of claims 1 to 4, wherein the first insulator ring and the second insulator ring have a non-linear interface therebetween.

11. The substrate support of any one of claims 1 to 4, further comprising a top ring disposed atop a top surface of the second insulator ring.

12. The substrate support of any one of claims 1 to 4, wherein the first insulator ring comprises at least one of quartz, alumina, anodized aluminum, or aluminum coated with yttrium oxide.

13. The substrate support of any one of claims 1 to 4, further comprising a dielectric member disposed on the body of the substrate support, wherein the dielectric member comprises a lip extending radially outward from a bottom portion of the dielectric member.

14. The substrate support of claim 13, further comprising an insert ring partially disposed on the lip of the dielectric member.

15. The substrate support of claim 14, wherein the insert ring is partially disposed on a projection disposed around an upper inner edge of the second insulator ring.

16. The substrate support of claim 15, wherein the protrusion is flush with or above the lip of the dielectric member.

17. A process chamber comprising: A chamber body having a substrate support disposed therein, wherein the substrate support is as described in any one of claims 1-16.

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