Gas injection process kit for arc elimination and improved uniform gas distribution for PVD processing

Abstract

Embodiments of a process shield for use in a processing chamber are provided herein. In some embodiments, a process shield for use in a processing chamber includes an annular body having an upper portion and a lower portion extending downward and radially inward from the upper portion, wherein the upper portion includes a plurality of annular grooves on an upper surface of the upper portion and has a plurality of slots disposed between the plurality of annular grooves to fluidly connect the plurality of annular grooves, wherein one or more inlets extend from an outer surface of the annular body to an outermost groove of the plurality of annular grooves.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure generally relate to substrate processing apparatuses. BACKGROUND

[0002] Plasma processing chambers generally include a substrate support for supporting a substrate and a target disposed relative to the substrate support. The target provides a source of material for sputtering onto the substrate during processing. RF power is provided to the plasma processing chamber to generate a plasma in a processing volume disposed between the target and the substrate support. Plasma processing chambers generally include a process kit for protecting the chamber walls from unwanted deposition and confining the plasma. The process kit generally includes a process shield. The space between the target and the process shield is referred to as a dark space. During substrate processing for high pressure processing (> 100 mTorr), contaminants (e.g., outgassing particles) can flow into the dark space, causing unwanted arcing.

[0003] Accordingly, the inventors have provided an improved process kit for use in a plasma processing chamber. SUMMARY

[0004] Embodiments of a process shield for use in a processing chamber are provided herein. In some embodiments, a process shield for use in a processing chamber includes a ring-shaped body having an upper portion and a lower portion extending downward and radially inward from the upper portion, wherein the upper portion includes a plurality of ring-shaped grooves on an upper surface of the upper portion and has a plurality of slots disposed between the plurality of ring-shaped grooves to fluidly connect the plurality of ring-shaped grooves, wherein one or more inlets extend from an outer surface of the ring-shaped body to an outermost groove of the plurality of ring-shaped grooves.

[0005] In some embodiments, a process kit for use in a processing chamber includes a process shield and a cover ring. The process shield has an upper portion and a lower portion extending downward and radially inward from the upper portion, wherein the upper portion includes a plurality of ring-shaped grooves on an upper surface of the upper portion and has a plurality of slots disposed between the plurality of ring-shaped grooves to fluidly connect the plurality of ring-shaped grooves, wherein one or more inlets extend from an outer surface of the process shield to an outermost groove of the plurality of ring-shaped grooves. The cover ring has a ring-shaped body disposed on the process shield.

[0006] In some embodiments, a processing chamber includes a chamber body having an interior volume in the chamber body, a substrate support disposed in the interior volume, a target disposed in the interior volume opposite the substrate support to at least partially define a processing volume between the target and the substrate support, a processing shield disposed about the substrate support and the target to define an outer boundary of the processing volume, wherein the processing shield and the target define a dark space gap between the processing shield and the target, and wherein the processing shield includes a plurality of annular grooves having a plurality of slots disposed between the plurality of annular grooves to fluidly connect the plurality of annular grooves to the dark space gap, and an isolator ring disposed between the target and the processing shield.

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

[0008] Embodiments of the present disclosure, briefly summarized above and discussed in greater detail below, can be understood by reference made to the illustrative embodiments of the disclosure depicted in the drawings. However, the drawings merely provide illustration of the typical embodiments of the disclosure and should therefore not be taken to limit the scope of the present disclosure as it can encompass other equally effective embodiments.

[0009] Figure 1 A schematic side view of a processing chamber having a processing kit is depicted in accordance with at least some embodiments of the present disclosure.

[0010] Figure 2 A schematic top view of a processing shield is depicted in accordance with at least some embodiments of the present disclosure.

[0011] Figure 3 A cross-sectional side view of a portion of a processing chamber having a processing kit is depicted in accordance with at least some embodiments of the present disclosure.

[0012] Figure 4 A cross-sectional side view of a portion of a processing chamber having a processing kit is depicted in accordance with at least some embodiments of the present disclosure.

[0013] For ease of understanding, the same identifiers have been used, where possible, to designate identical elements that are common to the figures. The figures are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment can be beneficially incorporated into other embodiments without further recitation. DETAILED DESCRIPTION

[0014] Embodiments of a process kit for use in a processing chamber are provided herein. The process kit includes a process shield disposed about a target to prevent unwanted deposition of target material on the chamber walls. The space between the target and the process shield is referred to as the dark space. Embodiments of the process shield provided herein advantageously include a plurality of gas passages for flowing a gas through the gas passages to the dark space, creating a gas curtain that prevents the flow of contaminants into the dark space and causing unwanted arcing. The gas can be a purge gas or one or more process gases. Where the gas includes one or more process gases, the plurality of gas passages advantageously provide improved uniformity of gas distribution into the processing chamber.

[0015] Figure 1 A schematic side view of a processing chamber 100 (e.g., a plasma processing chamber) having a process kit in accordance with at least some embodiments of the present disclosure is depicted. In some embodiments, the processing chamber 100 is a PVD (physical vapor deposition) processing chamber for reactive processing. However, other types of processing chambers configured for different processing can also be used or modified for use with embodiments of the process kit described herein.

[0016] The processing chamber 100 is a vacuum chamber, suitably adapted to maintain a sub-atmospheric pressure within the interior volume 120 during substrate processing. In some embodiments, the processing chamber 100 is suitably adapted for substrate processing at a pressure of about 1 mTorr to about 400 mTorr. In some embodiments, the processing chamber 100 is suitably adapted for substrate processing at a pressure of about 150 mTorr to about 350 mTorr. The processing chamber 100 includes a chamber body 106 covered by a lid assembly 104 that encloses a processing volume 119 located in the upper half of the interior volume 120. The chamber body 106 and the lid assembly 104 can be made of metal, such as aluminum. The chamber body 106 can be grounded via a connection to ground 115.

[0017] A substrate support 124 is disposed within the interior volume 120 to support and hold a substrate 122, such as a semiconductor wafer, for example, or other substrate that can be electrostatically held. The substrate support 124 can generally include an electrostatic chuck 150 disposed on a pedestal 136 and a hollow support shaft 112 for supporting the pedestal 136 and the electrostatic chuck 150. The electrostatic chuck 150 includes a dielectric plate having one or more electrodes 154 disposed therein. The pedestal 136 is generally made of metal, such as aluminum. The pedestal 136 is biasable and can be maintained at an electrically floating potential or grounded during plasma operation. The hollow support shaft 112 provides conduits to provide, for example, backside gas, process gas, fluid, coolant, power, etc. to the electrostatic chuck 150.

[0018] In some embodiments, the hollow support shaft 112 is connected to a lift mechanism 113 (e.g., an actuator or motor) to provide vertical movement of the electrostatic clamp 150 between an upper processing position (as shown in FIG. 1) and a lower transfer position (not shown). The bellows assembly 110 is disposed about the hollow support shaft 112 and connected between the electrostatic clamp 150 and the bottom surface 126 of the processing chamber 100 to provide a flexible seal that allows vertical movement of the electrostatic clamp 150 while preventing loss of pressure from within the processing chamber 100. The bellows assembly 110 also includes a lower bellows flange 164 that contacts the O-ring 165 or other suitable sealing element that contacts the bottom surface 126 to help prevent loss of chamber pressure. Figure 1

[0019] The hollow support shaft 112 provides a conduit for coupling the clamp power supply 140 and RF sources (e.g., the RF power supply 174 and the RF bias power supply 117) to the electrostatic clamp 150. In some embodiments, the RF power supply 174 and the RF bias power supply 117 are coupled to the electrostatic clamp 150 via respective RF matching networks (only the RF matching network 116 is shown). In some embodiments, the substrate support 124 can alternatively include AC or DC bias power.

[0020] The substrate lifter 130 can include lift pins 109 mounted on a platform 108 that is connected to a shaft 111 that is connected to a second lift mechanism 132 for raising and lowering the substrate lifter 130 so that the substrate 122 can be placed on or removed from the electrostatic clamp 150. The platform 108 can be in the form of a hoop lift. The electrostatic clamp 150 can include through-holes that receive the lift pins 109. A bellows assembly 131 is connected between the substrate lifter 130 and the bottom surface 126 to provide a flexible seal that maintains chamber pressure during vertical movement of the substrate lifter 130.

[0021] A target 138 is disposed in the processing volume 119 opposite the substrate support 124 to at least partially define the processing volume 119 therebetween. The substrate support 124 has a support surface having a plane that is substantially parallel to a sputtering surface of the target 138. In some embodiments, the target 138 is made of titanium, tantalum, or aluminum. The target 138 is connected to one or both of a DC power source 190 and / or the RF power supply 174. The DC power source 190 can apply a bias voltage to the target 138 relative to the processing shield 105.

[0022] ​The target 138 includes a sputtering plate 142 mounted to a backing plate 144. The sputtering plate 142 includes a material to be sputtered onto the substrate 122. The backing plate 144 is made of a metal, such as stainless steel, aluminum, copper chrome, or copper zinc. The backing plate 144 can be made of a material having a sufficiently high thermal conductivity to dissipate heat generated in the target 138 from eddy currents that occur in the sputtering plate 142 and the backing plate 144, and also from high energy ion bombardment onto the sputtering plate 142 from the generated plasma. In some embodiments, the backing plate 144 includes a recess 146 on a side opposite the sputtering plate 142.

[0023] In some embodiments, the processing chamber 100 includes a magnetic field generator 156 to form a magnetic field around the target 138 to improve sputtering of the target 138. The capacitively generated plasma can be enhanced by the magnetic field generator 156 in which, for example, a plurality of magnets 151 (e.g., permanent magnets or electromagnetic coils) can provide a magnetic field in the processing chamber 100 having a rotating magnetic field with an axis of rotation perpendicular to the plane of the substrate 122. Additionally or alternatively, the processing chamber 100 can include a magnetic field generator 156 that generates a magnetic field near the target 138 to increase ion density in the processing volume 119 to improve sputtering of the target material. The plurality of magnets 151 can be disposed in a cavity 153 in the lid assembly 104. A coolant (e.g., water) can be disposed in or circulated through the cavity 153 to cool the target 138.

[0024] The processing chamber 100 includes a process kit 102 that encloses various chamber components to prevent unwanted reactions between the components and ionized process materials. The process kit 102 includes a process shield 105 that surrounds the substrate support 124 and the target 138 to at least partially define the processing volume 119. For example, the process shield 105 can define an outer boundary of the processing volume 119. An outer peripheral surface of the target 138 and the process shield 105 define a dark space gap 194 therebetween. The dark space gap 194 is configured to prevent arcing between the target 138 and the process shield 105. In some embodiments, the process shield 105 is made of a metal, such as aluminum. In some embodiments, the process kit 102 includes a deposition ring 170 that is seated on an outer edge of the electrostatic clamp 150. In some embodiments, the process kit 102 includes a cover ring 180 disposed on the process shield 105 to form a tortuous gas flow path therebetween.

[0025] The processing chamber 100 is connected to and in fluid communication with a vacuum system 184 that includes a throttle valve (not shown) and a pump (not shown) for evacuating the processing chamber 100. The pressure inside the processing chamber 100 can be adjusted by adjusting the throttle valve and / or the pump. A slit valve 148 can be connected to the chamber body 106 and aligned with an opening in the sidewall of the chamber body 106 to facilitate the transfer of the substrate 122 into and out of the chamber body 106.

[0026] The processing chamber 100 is connected to a first gas supply 192 configured to supply one or more gases through the processing shield 105 and into the dark space gap 194 to advantageously create a gas curtain to prevent outgassing from the substrate 122 during processing from entering the dark space gap 194 and causing unwanted arcing. The first gas supply 192 can supply a purge gas or one or more process gases. In some embodiments, the first gas supply 192 can supply nitrogen, argon, or oxygen. In some embodiments, the processing chamber 100 can also be connected to and in fluid communication with a second gas supply 118 that can supply one or more process gases to the processing chamber 100 from a lower portion of the chamber body 106 (i.e., below the substrate 122) for processing the substrate 122 disposed therein. For example, the first gas supply 192 can provide nitrogen or oxygen while the second gas supply 118 provides argon.

[0027] In use, when the DC power source 190 supplies power to the target 138 and other chamber components connected to the DC power source 190, the RF power source 174 energizes the sputtering gas (e.g., from the first gas supply 192 or the second gas supply 118) to form a plasma of the sputtering gas. The formed plasma impacts and bombards the sputtering surface of the target 138 to sputter material from the target 138 onto the substrate 122. In some embodiments, the RF energy supplied by the RF power source 174 can range in frequency from about 2 MHz to about 60 MHz, or, for example, a non-limiting frequency such as 2 MHz, 13.56 MHz, 27.12 MHz, or 60 MHz can be used. In some embodiments, multiple RF power sources (i.e., two or more) can be provided to supply RF energy at multiple frequencies described above. Additional RF power sources (e.g., the RF bias power source 117) can also be used to supply a bias voltage to the substrate support 124 to attract ions from the plasma toward the substrate 122.

[0028] Figure 2A cross-sectional side view of portions of a process chamber having a process kit according to at least some embodiments of the present disclosure is depicted. The process kit 102 includes a process shield 105 having a generally annular body 202 including an upper portion 206 and a lower portion 208 extending downward and radially inward from the upper portion 206. In some embodiments, the upper portion 206 includes coolant channels 230 to circulate coolant through the coolant channels 230 to cool the process shield 105.

[0029] An isolator ring 210 is disposed between the target 138 and the process shield 105. In some embodiments, an upper surface 212 of the upper portion 206 includes a recess 228 to accommodate the isolator ring 210. In some embodiments, the upper portion 206 includes a plurality of annular grooves 204 on the upper surface 212 of the upper portion 206. In some embodiments, the plurality of annular grooves 204 extend downward from the recess 228. In some embodiments, the upper portion 206 includes an O-ring groove 232 radially outward of the plurality of annular grooves 204 to accommodate an O-ring 238 or other suitable gasket to provide a seal between the isolator ring 210 and the process shield 105.

[0030] The process shield 105 includes one or more inlets 218 extending from an outer surface 214 of the process shield 105 to an outermost groove 220 of the plurality of annular grooves 204. The one or more inlets 218 are fluidly connected to the first gas supply 192 to supply gas from the first gas supply 192 to the plurality of annular grooves 204. The process shield 105 includes a plurality of slots (discussed below with reference to Figure 3 to fluidly connect the plurality of annular grooves 204 and provide a gas flow path from the one or more inlets 218 to an innermost groove 222.

[0031] In some embodiments, the plurality of annular grooves 204 includes a second groove 224 and a third groove 226 disposed between the outermost groove 220 and the innermost groove 222. In some embodiments, each groove of the plurality of annular grooves 204 has a width of about 0.05 inches to about 0.2 inches. In some embodiments, each groove of the plurality of annular grooves 204 has a depth of about 0.3 inches to about 0.4 inches. Although Figure 2 Although the plurality of annular grooves 204 is depicted as including four grooves, the plurality of annular grooves 204 can include more than four grooves or fewer than four grooves. In some embodiments, all of the grooves of the plurality of annular grooves 204, except for the innermost groove 222, are disposed directly below the isolator ring 210. In some embodiments, all of the grooves of the plurality of annular grooves 204 have substantially similar widths and depths. In some embodiments, substantially similar or about can be within about 10%.

[0032] Figure 3 A schematic top view of a process shield 105 is depicted in accordance with at least some embodiments of the present disclosure. A first gas supply 192 is fluidly connected to one or more inlets 218. In some embodiments, the one or more inlets 218 include four inlets extending to an outermost groove 220. The process shield 105 includes a plurality of slots 306 between each of the plurality of annular grooves 204 to fluidly connect the outermost groove 220 to an innermost groove 222. In some embodiments, an inner ring 250 of the process shield 105 disposed radially inward of the innermost groove 222 has a continuous surface facing the process volume.

[0033] In some embodiments, the plurality of slots 306 are arranged such that they provide substantially equal flow paths from the one or more inlets 218 to the innermost groove 222. In some embodiments, the number of the plurality of slots 306 between adjacent annular grooves 204 of the plurality of annular grooves 204 increases from the outermost groove 220 to the innermost groove 222. In some embodiments, the plurality of slots 306 doubles between adjacent annular grooves 204 of the plurality of annular grooves 204 from the outermost groove 220 to the innermost groove 222.

[0034] For example, in some embodiments, the plurality of slots 306 includes 8 slots between the outermost groove 220 and a second groove 224. In some embodiments, the 8 slots between the outermost groove 220 and the second groove 224 are disposed at regular intervals. In some embodiments, the plurality of slots 306 includes 16 slots between the second groove 224 and a third groove 226. In some embodiments, the 16 slots between the second groove 224 and the third groove 226 are disposed at regular intervals. In some embodiments, the plurality of slots 306 includes 32 slots between the third groove 226 and the innermost groove 222. In some embodiments, the 32 slots between the third groove 226 and the innermost groove 222 are disposed at regular intervals.

[0035] Referring back to Figure 2A first gap 240 is disposed between an inner surface of the isolator ring 210 and an outer surface of the inner ring 250 of the upper portion 206 (i.e., the opposing surface of the process shield 105). The first gap 240 is fluidly connected to the innermost groove 222. For example, the first gap 240 can be disposed above the innermost groove 222 such that an open bottom portion of the first gap 240 coincides with at least a portion of an open top portion of the innermost groove 222. In some embodiments, a width of the first gap 240 is less than a width of the innermost groove 222. In some embodiments, the first gap is about 0.02 inches to about 0.1 inches. A second gap 242 is disposed between an upper surface of the inner ring 250 and the target material 138. A dark space gap 194 is disposed between an inner surface of the inner ring 250 and the target material 138. A flow path extends from the first gas supply 192 through one or more of the inlets 218, through the plurality of annular grooves 204, through the first gap 240, through the second gap 242, through the dark space gap 194, and into the process volume 119. The first gap 240 is maintained at a substantially uniform distance around the process shield 105 to advantageously provide a more uniform gas distribution into the process volume 119, and thus a more uniform mixing of the gas provided by the first gas supply 192 and the target material. In embodiments where a width of the first gap 240 is less than a width of the innermost groove 222, the first gap 240 provides a flow restriction that advantageously provides a more uniform gas distribution into the process volume 119, and thus a more uniform mixing of the gas provided by the first gas supply 192 and the target material.

[0036] In some embodiments, the lower portion 208 includes a first leg 244 extending downward from the upper portion 206. In some embodiments, the lower portion 208 includes a first ledge 246 extending radially inward from the first leg 244. In some embodiments, the lower portion 208 includes an inner lip 248 extending upward from the first ledge 246. In some embodiments, the first leg 244 is free of through-holes. In some embodiments, the inner lip 248 is free of through-holes.

[0037] In some embodiments, a cover ring 180 is disposed on the process shield 105. The cover ring 180 generally includes an annular body 252 having a lower groove 254 on a lower surface of the annular body 252 to accommodate the inner lip 248. In some embodiments, the inner lip 248 and the lower groove 254 form a tortuous gas flow path. In some embodiments, an upper surface 216 of the cover ring 180 is tilted radially downward and inward. The cover ring 180 and the deposition ring 170 form a tortuous gas flow path therebetween.

[0038] Figure 4A cross-sectional side view of portions of a process chamber having a process kit according to at least some embodiments of the present disclosure is depicted. In some embodiments, one or more centering bushings 410 are connected to the process shield 105 to center the cover ring 180 to the process shield 105. In some embodiments, the cover ring 180 includes outer legs 416 and inner legs 426 extending downward from the annular body 252 on either side of the lower groove 254. In some embodiments, the outer legs 416 include one or more slots 420 for receiving one or more centering bushings 410. In some embodiments, the one or more centering bushings 410 include 3 bushings. In some embodiments, the one or more centering bushings 410 are disposed at regular intervals. In some embodiments, the one or more centering bushings 410 are connected to the process shield 105 via fasteners 430. In some embodiments, the one or more centering bushings 410 extend into openings 450 in the first ledge 246.

[0039] In some embodiments, the one or more centering bushings 410 have a circular upper surface. In some embodiments, the one or more slots 420 have angled sidewalls 424. In some embodiments, the angled sidewalls of the one or more slots 420 extend downward and outward at an angle of about 5 degrees to about 15 degrees. The angled sidewalls of the one or more slots 420 and the circular upper surface of the one or more centering bushings 410 advantageously enable repeatable concentric placement and allow for concentric thermal expansion of the cover ring 180 relative to the process shield 105. In some embodiments, the one or more centering bushings 410 have a diameter of about 0.3 to about 0.5 inches to advantageously minimize disruption of tortuous gas flow paths between the process shield 105 and the cover ring 180.

[0040] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure can be devised without departing from the basic scope thereof.

Claims

1. A processing shield for use in a processing chamber, comprising: An annular body having an upper portion and a lower portion, the lower portion extending downward and radially inward from the upper portion, wherein the upper portion includes a plurality of grooves on its upper surface and has a plurality of slots disposed between the plurality of grooves to fluidly connect the plurality of grooves, wherein one or more inlets extend from the outer surface of the annular body to the outermost groove of the plurality of grooves, and wherein the upper surface of the annular body includes a recess to receive an isolator ring, and the plurality of grooves extend downward from the lower surface of the recess.

2. The processing shield according to claim 1, wherein the number of the plurality of slots between adjacent recesses of the plurality of recesses increases from the outermost recess to the innermost recess.

3. The processing shielding component according to claim 2, wherein the plurality of grooves includes a second groove and a third groove disposed between the outermost groove and the innermost groove, and wherein the plurality of slots includes 8 slots located between the outermost groove and the second groove, 16 slots located between the second groove and the third groove, and 32 slots located between the third groove and the innermost groove.

4. The processing shield according to claim 1, wherein the one or more inlets include four inlets.

5. The processing shield according to any one of claims 1 to 4, wherein the upper portion includes a coolant channel.

6. The processing shield according to any one of claims 1 to 4, wherein the plurality of grooves have a width of about 0.05 inches to about 0.2 inches.

7. The processing shield according to any one of claims 1 to 4, wherein the upper portion includes an O-ring groove located radially outside the plurality of grooves.

8. The processing shield according to any one of claims 1 to 4, wherein the lower portion includes a first leg extending downward from the upper portion, a first bracket extending radially inward from the first leg, and an inner lip extending upward from the first bracket, wherein the first leg does not have a through hole.

9. A processing kit for use in a processing chamber, comprising: The processing shielding element according to any one of claims 1 to 4; and A cover ring having an annular body disposed on the processing shield.

10. The processing kit of claim 9, further comprising one or more centering bushings connected to the processing shield to center the cover ring to the processing shield.

11. The processing kit of claim 10, wherein the cover ring includes an outer leg and an inner leg extending downward from the annular body, and wherein the outer leg includes one or more slots for receiving the one or more centering bushings.

12. The processing kit of claim 9, wherein the one or more centering bushings comprise three bushings.

13. The processing kit according to any one of claims 9 to 12, wherein the number of the plurality of slots between adjacent recesses of the plurality of recesses increases from the outermost recess to the innermost recess.

14. A processing chamber, comprising: A chamber body having an internal volume within the chamber body; A substrate support member disposed within the internal volume; A target material disposed in the internal volume opposite to the substrate support, to at least partially define a processing volume between the target material and the substrate support; The processing shielding member according to any one of claims 1 to 4, wherein the processing shielding member is disposed around the substrate support and the target to define an outer boundary of the processing volume, wherein the processing shielding member and the target define a dark space gap between the processing shielding member and the target, and the plurality of grooves of the processing shielding member are connected to the dark space gap; and An isolator ring is disposed between the target material and the processing shield.

15. The processing chamber of claim 14, further comprising a first gas supply for allowing one or more gases to flow from the first gas supply through the plurality of grooves to the dark space gap.

16. The processing chamber of claim 14, further comprising a second gas supply configured to supply one or more gases from the lower portion of the chamber body to the processing chamber.

17. The processing chamber of claim 14, wherein the processing shield includes a recess on the upper surface of the processing shield, wherein the plurality of grooves extend from the recess, and wherein the isolator ring is disposed in the recess.

18. The processing chamber of claim 14, wherein the processing shield includes a coolant passage configured to allow coolant to flow through it.

19. The processing chamber of claim 14, wherein the gap between the inner surface of the isolator ring and the opposing surface of the processing shield is about 0.02 inches to about 0.1 inches.

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