Showerhead assembly with heated showerhead

Abstract

In some embodiments, a showerhead assembly includes: a heated showerhead having a heater plate and a gas distribution plate coupled to the heater plate; an ion filter spaced apart from the heated nozzle; a spacer ring in contact between the heated showerhead and the ion filter; a remote plasma region between the heated showerhead and the ion filter; an upper isolator spaced apart from the spacer ring and supported on the ion filter; a seal ring secured to the heated showerhead, sealing against the upper isolator and pushing the upper isolator against the ion filter; a gap between the bottom of the gas distribution plate and the top of the ion filter, the gap being in fluid communication with the remote plasma region; a first channel extending through the heater plate; and a second channel in communication with the first channel and extending through the gas distribution plate, the second channel extending to the gap.

Description

Technical Field

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

[0002] Plasma processing equipment typically includes a processing chamber configured to perform certain processes on a substrate, such as chemical vapor deposition (CVD), atomic layer deposition (ALD), etching, and the like. When performing certain processes, such as plasma processing, some processing chambers may use a showerhead to distribute process gases onto the substrate. However, the present inventors have observed that, for example, in metal plasma enhanced chemical vapor deposition (PECVD) applications, separating electrically heated and grounded components in an environment with gaseous metal compounds can be difficult.

[0003] The present inventors therefore provide specific embodiments of improved showerheads as disclosed herein. Summary of the Invention

[0004] Methods and apparatus for processing substrates are provided herein. In some embodiments, a showerhead assembly for a processing chamber includes: a heated showerhead having a heater plate and a gas distribution plate coupled to the heater plate; an ion filter spaced apart from the heated showerhead; a spacer ring in contact between the heated showerhead and the ion filter; a remote plasma region defined between the heated showerhead and the ion filter; an upper isolator spaced apart from the spacer ring and supported on a portion of the ion filter radially outward of the spacer ring; a sealing ring secured to the heated showerhead, sealing against the upper isolator and urging the upper isolator against the ion filter; a gap located radially inward of the spacer ring, the gap being between a bottom of the gas distribution plate and a top of the ion filter, the gap being in fluid communication with the remote plasma region; a first channel extending through the heater plate; and a second channel communicating with the first channel and extending through the gas distribution plate, the second channel extending to the gap.

[0005] In some specific embodiments, a showerhead assembly for a processing chamber includes: a heated showerhead, the heated showerhead having a heater plate and a gas distribution plate coupled to the heater plate; an ion filter, the ion filter being spaced apart from the heated showerhead; a spacer ring, the spacer ring being in contact between the heated showerhead and the ion filter, the spacer ring being thermally conductive and electrically insulating, the spacer ring being composed of a plurality of elements spaced apart from each other along an interface between the heated showerhead and the ion filter; a remote plasma region, the remote plasma region being defined between the heated showerhead and the ion filter; and an upper isolator, the upper isolator being spaced apart from the spacer ring and supported radially outward of the spacer ring. on a portion of the ion filter on one side; a sealing ring, the sealing ring being attached to the heated shower head, sealing against the upper isolator and pushing the upper isolator against the ion filter; a gap, the gap being on the radially inner side of the spacing ring, the gap being between the bottom of the heated shower head and the top of the ion filter, the gap being connected to the remote plasma region fluid; a first channel, the first channel extending through the heater plate; and a second channel, the second channel being connected to the first channel and extending through the gas distribution plate, the second channel extending to the gap; and a volume defined by the heated shower head, the ion filter, the sealing ring, the upper isolator and the spacing ring, wherein the volume is connected to the gap fluid.

[0006] In some embodiments, a processing chamber includes: a chamber body having an interior volume; a substrate support disposed in the interior volume; and a showerhead assembly disposed in the interior volume opposite the substrate support, wherein the showerhead assembly includes: a heated showerhead having a heater plate and a gas distribution plate coupled to the heater plate; an ion filter spaced apart from the heated showerhead; a spacer ring in contact between the heated showerhead and the ion filter; and a remote plasma region defined between the heated showerhead and the ion filter. ; an upper isolator, the upper isolator is spaced apart from the spacer ring and supported on a portion of the ion filter radially outside the spacer ring; a sealing ring, the sealing ring is fastened to the heated nozzle, seals against the upper isolator and pushes the upper isolator against the ion filter; a first gap, the first gap is located on the radial inner side of the spacer ring, the first gap is located between the bottom of the gas distribution plate and the top of the ion filter, and the first gap is connected to the remote plasma region fluid; a first channel, the first channel extends through the heater plate; and a second channel, the second channel is connected to the first channel and extends through the gas distribution plate, and the second channel extends to the first gap.

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

[0008] Embodiments of the present disclosure, briefly summarized above and discussed in greater detail below, may be understood by reference to the illustrative embodiments of the disclosure depicted in the accompanying drawings. However, the drawings illustrate only typical embodiments of the disclosure and are therefore not to be considered limiting of its scope, as the disclosure may admit to other equally effective embodiments.

[0009] Figure 1 is a partially schematic cross-sectional view of a processing chamber according to at least some embodiments of the present disclosure.

[0010] Figure 2 is a plan view of a heat transfer ring according to at least some embodiments of the present disclosure.

[0011] Figure 3 yes Figure 2 A cross-sectional view of the heat transfer ring along line 3-3.

[0012] Figure 4 is a flow chart of a plasma processing method according to at least some embodiments of the present disclosure.

[0013] Figure 5 is a schematic side view of a portion of a showerhead assembly according to at least some embodiments of the present disclosure.

[0014] Figure 6 is a schematic side view of a portion of a showerhead assembly according to at least some embodiments of the present disclosure.

[0015] Figure 7 is a schematic side view of a portion of a showerhead assembly according to at least some embodiments of the present disclosure.

[0016] Figure 8 yes Figure 7 An isometric cross-sectional view of a portion of a sprinkler head assembly.

[0017] Figure 9 is a schematic side view of a portion of a showerhead assembly according to at least some embodiments of the present disclosure.

[0018] Figure 10 yes Figure 9 An isometric cross-sectional view of a portion of a sprinkler head assembly.

[0019] Figure 11 is a schematic side view of a portion of a showerhead assembly according to at least some embodiments of the present disclosure.

[0020] Figure 12 is a schematic side view of a portion of a showerhead assembly according to at least some embodiments of the present disclosure.

[0021] To facilitate understanding, identical reference numerals have been used wherever possible to designate identical elements in the drawings. The figures are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be beneficially incorporated into other embodiments without further description. DETAILED DESCRIPTION

[0022] Methods and apparatus for processing substrates in a PECVD chamber are provided. In some embodiments, a radio frequency (RF) plasma can be formed between the showerhead and the ion filter, separated by an aluminum nitride (AlN) spacer on the periphery. A strong argon purge prevents metal vapor from reaching the insulator. The argon purge is contained within a remote cavity by a ring secured to the showerhead and pressed against an outer ceramic ring to form a seal.

[0023] Described herein are specific embodiments of apparatus and methods for providing a plasma to a processing chamber that may reduce or eliminate condensation or deposition of material from the plasma in the area of ​​a showerhead assembly.

[0024] The present inventors have observed that some showerheads in plasma processing chambers operate at temperatures that allow material to condense or deposit from the plasma in undesirable areas of the processing chamber, such as in portions of the showerhead assembly. This accumulation of material can undesirably lead to arcing between electrically heated and grounded portions of the showerhead assembly. According to one aspect, embodiments of a showerhead assembly are described that advantageously reduce or eliminate undesirable deposition in areas of the showerhead assembly that can lead to arcing.

[0025] Figure 1 is a partial cross-sectional view of a process chamber 100 suitable for depositing a material (e.g., TiCl3) on a substrate. The process chamber 100 can be any process chamber suitable for plasma-enhanced semiconductor processing, such as a process chamber configured to perform plasma-assisted chemical vapor deposition (CVD) or atomic layer deposition (ALD) processes. An exemplary process chamber can include a process chamber available from Applied Materials, Inc. of Santa Clara, California. Other process systems, including those produced by other manufacturers, can benefit from the specific embodiments described herein.

[0026] Therefore, in some specific embodiments, Figure 1As shown, the processing chamber 100 includes a chamber body 102 having a lid 104, sidewalls 106, and a bottom wall 108 defining an interior volume 110. A susceptor 112 (e.g., a substrate support) is disposed within the interior volume 110 of the processing chamber 100. The susceptor 112 can be made of aluminum, ceramic, or other suitable materials. In some embodiments, the susceptor 112 is made of a ceramic material, such as aluminum nitride, which is a material suitable for use in high temperature environments, such as plasma processing environments, without causing thermal damage to the susceptor 112. The susceptor 112 can be moved vertically within the interior volume 110 along an axis AA using a lift mechanism (not shown).

[0027] The pedestal 112 may include an embedded heater element 114 adapted to control the temperature of a substrate 116 supported on the pedestal 112. In some embodiments, the pedestal 112 may be resistively heated by applying an electric current from a power source 118 to the heater element 114. In some embodiments, the heater element 114 may be comprised of a ferrite-coated ferrite encapsulated in a nickel-iron-chromium alloy (e.g., ) sleeve. The current provided by the power supply 118 is regulated by the controller 120 to control the heat generated by the heater element 114 to maintain the substrate 116 and the susceptor 112 at a substantially constant temperature during film deposition within any suitable temperature range.

[0028] A temperature sensor 122, such as a thermocouple, may be embedded in the susceptor 112 to monitor the temperature of the susceptor 112 in a conventional manner. The controller 120 uses the measured temperature to control the power supplied to the heater element 114 to maintain the substrate at a desired temperature.

[0029] The base 112 generally includes a plurality of lift pins (not shown) disposed therethrough that are configured to lift the substrate 116 from the base 112 and facilitate exchanging the substrate 116 with a robot (not shown) in a conventional manner.

[0030] A vacuum pump 124 is coupled to a port formed in the bottom wall 108 of the chamber body 102 and to a pumping ring 126 surrounding the pedestal 112. The pumping ring 126 has a fluid passage 127 in fluid communication with the processing volume 178. The vacuum pump 124 is used to maintain a desired gas pressure in the processing chamber 100. The vacuum pump 124 also exhausts post-processing gases and process byproducts from the processing chamber 100 through the pumping ring 126.

[0031] In some specific embodiments, Figure 1As shown, the cover 104 includes a plurality of fluid channels 104a extending within the cover. The fluid channels 104a are fluidically coupled to a source of heat transfer fluid (e.g., water). The fluid channels 104a are configured to flow the heat transfer fluid to control the temperature of the cover 104 and the interior volume 110. The cover 104 also includes an opening 128 through which a plurality of gas conduits 130 extend. In some embodiments, the cover 104 can be formed from aluminum. In some embodiments, such as Figure 1 As shown, the gas conduit 130 is at least partially surrounded by an outer tube 132 extending downwardly from the lid 104 and a bellows 134 extending downwardly from the outer tube 132. In some embodiments, the bellows 134 can be welded to the heater plate 148 to prevent precursors from leaking into the purge volume 191 outside of the outer tube 132 and the bellows 134.

[0032] The bellows 134 supports a showerhead assembly 140 disposed in the interior volume 110 opposite the base 112. In particular embodiments, the bellows 134 allows some movement of the showerhead assembly 140 in an axial direction along the axis AA. Moreover, the showerhead assembly 140 is supported by a lower isolator 142, which is supported by a pumping ring 126, which can be fixed in place to the chamber body 102. For example, the pumping ring can be fixed to at least one of the sidewalls 106 or the bottom wall 108. The lower isolator 142 can be at least partially disposed between the ion filter 146 and the pumping ring 126. The lower isolator 142 can support the ion filter spaced above the base 112. The lower isolator 142 can include any process-compatible electrically insulating material. For example, in some specific embodiments, the electrical insulator ring can be made of quartz (SiO2), a sintered ceramic such as aluminum oxide (Al2O3) or silicon nitride (SiN), or single crystal sapphire (Al2O3).

[0033] The showerhead assembly 140 includes a heated showerhead 144, an ion filter 146, and a spacer ring 180 in contact between the heated showerhead 144 and the ion filter 146. The heated showerhead 144 includes a heater plate having a central opening through which the gas conduit 130 extends. The heater plate 148 is connected to the bellows 134 along an upper side. In specific embodiments, the heater plate 148 may include an embedded heater element 150 suitable for controlling the temperature of the showerhead assembly 140. In some specific embodiments, the heater plate 148 can be resistively heated by applying an electric current from a power supply 152 to the heater element 150. In some specific embodiments, the heater element 150 can be made of a material encapsulated in a nickel-iron-chromium alloy (e.g., ) sleeve. The current supplied from power supply 152 is regulated by controller 154 to control the heat generated by heater element 150, thereby maintaining ion filter 146 at a substantially constant temperature during film deposition in any suitable temperature range. The supplied current can be adjusted to selectively control the temperature of the ion filter to above 575 degrees Celsius.

[0034] A temperature sensor 156, such as a thermocouple, may be embedded in the ion filter 146 to monitor the temperature of the ion filter 146. Since the ion filter 146 is located in an area of ​​the showerhead assembly 140 where plasma will be present and condensation may occur, the temperature of the ion filter 146 is used to control the heater element 150. Thus, in some embodiments, as shown in FIG. Figure 1 As shown, the controller 154 uses the measured temperature of the ion filter 146 to control the power supplied to the heater element 150 to maintain the ion filter 146 at a desired temperature above the condensation temperature of species in the plasma.

[0035] The heated showerhead 144 also includes a gas distribution plate 158 extending parallel to the heater plate 148. In some embodiments, such as Figure 1 As shown, the gas distribution plate 158 and the heater plate 148 are connected at their respective outer edges 158a and 148a and define a first plenum 160. The gas distribution plate 158 includes a plurality of through-holes 158b that allow gas to flow from the gas conduit 130 through the gas distribution plate 158. In some specific embodiments, the heater plate 148 and the gas distribution plate 158 can be formed of nickel.

[0036] The ion filter 146 extends parallel to the gas distribution plate 158 and is axially spaced apart from the gas distribution plate 158. A second plenum 162 (e.g., a remote cavity) is defined between the ion filter 146 and the gas distribution plate 158. In some embodiments, as Figure 1 As shown, the ion filter 146 has a flange 146a, with an upper side 164 of the flange 146a facing the flange 144a of the heated showerhead 144. Moreover, the flange 146a of the ion filter 146 has a lower side 166 facing the lower separator 142. The flanges 144a and 146a include corresponding grooves 168, 170, which define the interface between the heated showerhead 144 and the ion filter 146. The grooves 168, 170 can extend along a circular interface centered on the axis AA. In some embodiments, as shown in FIG. Figure 1 As shown, the grooves 168, 170 may have an arcuate cross-sectional profile, although other shapes may be used. The ion filter 146 includes a plurality of through holes 146b that allow gas to flow through the ion filter 146. In some embodiments, the ion filter 146 may be formed of nickel.

[0037] In some embodiments, the through holes 158b in the gas distribution plate 158 and the through holes 146b in the ion filter 146 can be used to introduce gas from the gas panel 172 into the processing chamber 100 via the gas conduit 130 and the showerhead assembly 140. The through holes 158b and 146b can have different sizes, numbers and distributions, shapes, designs, and diameters to facilitate the flow of various process gases for different processing purposes. For example, in some embodiments, a plasma can be formed from the process gas mixture exiting the showerhead assembly 140 to enhance thermal decomposition of the process gases in the process gas mixture, resulting in deposition of material on the surface of the substrate.

[0038] Spacer ring 180 is located in grooves 168 and 170 at the interface between flanges 144a and 146a. Spacer ring 180 is thermally conductive and electrically insulating. In some embodiments, spacer ring 180 is formed of aluminum nitride. Figure 2 As shown in greater detail, and in some embodiments, the spacer ring 180 includes a plurality of elements 182 configured to be arranged along the interface. Figure 2 In the exemplary embodiment shown, the elements 182 are formed as arcuate segments and arranged along a circle. The elements 182 are spaced apart from each other (e.g., circumferentially) by gaps 184 that are of sufficient size to allow the elements 182 to expand and fill the gaps based on the thermal expansion coefficient of the material of the elements 182 without cracking or otherwise damaging the elements 182 when the elements 182 are at or above a predetermined temperature. In one example, at room temperature, the gaps 184 between the elements are approximately 5 mm to 7 mm to allow for expansion at processing temperatures of 575 degrees Celsius to 600 degrees Celsius. Furthermore, because the gaps 184 between the elements 182 may create leak paths if not closed or restricted, in operation, the temperature of the spacer ring 180 may increase to cause the elements 182 to expand, thereby reducing the size of the gaps 184 before gas is introduced into the showerhead assembly 140 via the gas conduit 130.

[0039] In some specific embodiments, Figure 3 As shown, the cross-section of the element 182 can be a circular cross-section or a tubular cross-section. In some embodiments, the spacer ring 180 includes at least fifteen elements. In some embodiments, the heat transfer ring includes eighteen to thirty-six elements.

[0040] like Figure 1As shown, when the spacer ring 180 is seated in the grooves 168, 170, the flanges 144a and 146a are maintained spaced apart from each other by a gap 174 on the radially inner side of the spacer ring 180. Therefore, in some embodiments, the heated showerhead 144 and the ion filter 146 are not in direct contact with each other, but are only indirectly connected through the spacer ring 180. In some embodiments, the gap 174 is about 5 mm to 7 mm. The gap 174 provides a plasma confinement feature for the remote plasma (e.g., the remote plasma region) in the second gas chamber 162. The gap 174 is in fluid communication with the second gas chamber 162. In a specific embodiment, the gap 174 is in fluid communication with the purge channel 196 and the purge gas source 198. In a specific embodiment, before the process gas is introduced into the showerhead assembly 140 via the gas conduit 130, the purge gas can be introduced into the second gas chamber 162 via the purge channel 196 and the gap 174. In some embodiments, as Figure 1 As shown, the purge channel 196 can be connected (eg, welded) to the heater plate 148. In some embodiments, the purge channel can be attached to the bellows 134.

[0041] In some specific embodiments, Figure 1 As shown, flange 146a of ion filter 146 can be separated from lower isolator 142 by gap 176. Gap 176 can be approximately 5 mm to 7 mm. Gap 176 can facilitate direct plasma confinement between ion filter 146 and substrate 116. Gap 176 is in fluid communication with processing volume 178 between ion filter 146 and substrate 116. In some embodiments, gap 176 is in fluid communication with purge passage 197 and purge gas source 199. In some embodiments, purge gas can flow from purge passage 197 and gap 176 into processing volume 178 before the processing gas is introduced from gas conduit 130 into showerhead assembly 140. Pumping ring 126 is also in fluid communication with processing volume 178. Purge gas in processing volume 178 can be exhausted from processing volume 178 via pumping ring 126.

[0042] The heated showerhead 144, ion filter 146, and pedestal 112 can be configured as electrodes. In one embodiment, pedestal 112 includes at least one electrode 192 for retaining substrate 116 on pedestal 112. Electrode 192 is driven by an adsorption power source 188 to generate an electrostatic force that retains substrate 116 to the pedestal surface, as is conventionally known. Alternatively, substrate 116 can be retained to pedestal 112 by clamping, vacuum, or gravity.

[0043] In some embodiments, the pedestal 112 is configured as a cathode having an electrode 192 embedded therein that is connected to the RF bias power supplies 185, 186. Figure 1The exemplary embodiment depicted in FIGURE 1 illustrates two RF bias power supplies 185, 186, but the number of RF bias power supplies can be any number as desired. The RF bias power supplies 185, 186 are coupled between an electrode 192 disposed in the pedestal 112 and another electrode (e.g., a heated showerhead 144, an ion filter 146, or a lid 104 of the processing chamber 100). One or both of the RF bias power supplies 185, 186 ignites and sustains a plasma discharge formed from a gas disposed in the processing volume 178 of the processing chamber 100.

[0044] exist Figure 1 In the illustrated embodiment, dual RF bias power supplies 185, 186 are coupled to an electrode 192 disposed in the pedestal 112 via a matching circuit 194. The signals generated by the RF bias power supplies 185, 186 are transmitted to the pedestal 112 via a single feed via the matching circuit 194 to ionize the gas mixture provided in the processing chamber 100, thereby providing the ion energy required to perform deposition or other plasma-enhanced processes. The RF bias power supplies 185, 186 are typically capable of generating RF signals having a frequency of about 50 kHz to about 200 MHz and a power between about 0 watts and about 5000 watts.

[0045] One or more RF sources 147 provide a bias potential to the showerhead assembly 140 via a matching network to facilitate generation of a plasma between the showerhead assembly 140 and the pedestal 112. Alternatively, the RF source 147 and matching network 145 can be coupled to the showerhead assembly 140, the pedestal 112, or both, or to an antenna (not shown) disposed external to the processing chamber 100. In some embodiments, the RF source 147 can provide a power between about 10 watts and about 3000 watts at a frequency between about 30 kHz and about 13.6 MHz. Alternatively, the RF source 147 can be a microwave generator that provides microwave power to the heated showerhead 144, which facilitates generation of a plasma within the interior volume 110.

[0046] The gas distribution plate 158 includes a plurality of through-holes 158 b that fluidly couple the first plenum 160 to the second plenum 162, allowing the process gas in the first plenum 160 to pass through the gas distribution plate 158 and into the second plenum 162. The ion filter 146 includes a plurality of through-holes 146 b that allow activated species (e.g., free radicals) generated in the plasma to flow from the second plenum 162 to the processing volume 178 of the processing chamber 100. The second plenum 162 provides a second cavity or space to allow the ignition of the process gas to form a plasma, and further allows the accumulation of the plasma to promote the dispersion of plasma species through the through-holes 146 b. In some embodiments, during plasma processing, the vacuum pump 124 provides a negative pressure in the processing volume 178 relative to the second plenum 162, thereby allowing species in the second plenum 162 to flow into the processing volume 178. Providing multiple regions for forming plasma (eg, in the second plenum 162 and the processing volume 178) provides multiple excitation stages of the plasma to promote enhanced radical generation compared to plasma sources that may utilize a single cavity to form the plasma.

[0047] Before use in plasma processing, the showerhead assembly 140 can be seasoned, for example, to coat the surface of the showerhead assembly 140 with TiN. Seasoning can also prevent metal from the showerhead assembly from contaminating the substrate during plasma processing. Gas conduit 130 can be connected to various gas supplies, such as TiCl4, N2, and NH3. In at least some embodiments, first chamber 160 can be purged with N2 from gas conduit 130, second chamber 162 can be purged with N2 supplied via gap 174, and process volume 178 can be purged with N2 supplied via gap 176. Once purged, TiCl4 and NH3 are separately introduced into first chamber 160 and heated and mixed in first chamber 160 while the heater is operating and the temperature of ion filter 146 is at or above 575 degrees Celsius. By mixing and heating the TiCl4 and NH3 in the first chamber, low-temperature mixing of the TiCl4 and NH3 can be minimized, thereby facilitating thermal TiN seasoning. Once the showerhead assembly 140 is thermally aged, the first plenum 160, the second plenum 162, and the processing volume 178 may be purged again as described above before reactant gases are introduced into the showerhead assembly 140 via the gas conduit 130 for plasma processing.

[0048] Figure 4A plasma treatment method 400 according to the present disclosure is illustrated. The method can be performed after the showerhead assembly 140 is aged. The exemplary method described herein is described in the context of depositing TiCl3 from TiCl4. However, the method is not limited to these materials. At block 402, the heater element 150 is turned on to raise the temperature of the ion filter 146 to a temperature at which the substances in the desired gas plasma do not condense (e.g., at least 575 degrees Celsius). At block 404, process gases (e.g., H2, TiCl4) are separately introduced into the first gas chamber 160 via the gas panel 172 and the gas conduit 130. The process gases are mixed and heated in the first gas chamber 160 and flow through the through holes 158b of the gas distribution plate 158 into the second gas chamber 162. At block 406, a plasma is generated in the second gas chamber 162 and the processing volume 178. At block 408, the species (e.g., TiCl3) in the second plenum 162 passes through the through-holes 146b of the ion filter 146, thereby allowing the species to flow to the processing volume 178 and deposit on the surface of the substrate 116. The temperature of the ion filter 146 can be maintained above the temperature at which species in the plasma condense, resulting in improved higher density and uniformity of species along the substrate 116. By providing a purge or cleaning gas flow to a region of the showerhead assembly as described above, material deposition in that region can be reduced or eliminated, which can advantageously reduce or eliminate arcing during metal deposition, for example.

[0049] Figure 5 is a schematic side view of a portion of a showerhead assembly 500 , according to at least some embodiments of the present disclosure. Figure 6 is a schematic side view of a portion of a showerhead assembly 600 according to at least some embodiments of the present disclosure. Figure 5 and Figure 6 As shown, a gas (e.g., a purge gas such as argon or a cleaning gas such as chlorine) can be provided, for example, via a first channel 502 in the heater plate 148 and continued via a second channel 504 in the gas distribution plate 158 to the area or space (e.g., gap 174) between the showerhead and the ion filter 146 adjacent the spacer ring 180. Figure 5 As shown, the gap 174 is located on the radially inner side of the spacer ring 180. An upper isolator 506 may be disposed atop the lower isolator 142 and surround the gas distribution plate 158 and the spacer ring 180. The upper isolator 506 may be made of the same material as the lower isolator 142. A sealing ring 508 may be disposed atop the gas distribution plate 158 and the upper isolator 506 to provide a better seal between the periphery of the gas distribution plate 158 and the ion filter 146.

[0050] The sealing ring 508 can be made of a suitable process-compatible material to withstand the high temperatures and processing environment, such as nickel or ceramic-coated titanium (e.g., an alumina coating). In some embodiments, the thickness of the sealing ring 508 can be approximately 20-50 parts per thousand, although other thicknesses may be used in other applications. The sealing ring 508 can be fastened (e.g., screwed or bolted) to the gas distribution plate 158 and extend radially outward from the gas distribution plate 158. In some embodiments, a plurality of screws (not shown), such as approximately 12-16 screws, can be provided, such as approximately azimuthally uniformly spaced, to secure the sealing ring 508 to the gas distribution plate 158. For example, in a typical PECVD deposition of titanium using the gas distribution plate 158 assembly described herein, the inventors observed TiCl concentrations as low as 1 part per million near the gap 174 and the sealing ring 508.

[0051] The cantilevered portion 510 of the sealing ring 508 provides a spring biasing force against the upper isolator 506, pushing the upper isolator 506 downward against the ion filter 146 to improve the seal between the gas distribution plate 158 and the sealing ring 508, between the sealing ring 508 and the upper isolator 506, and between the upper isolator 506 and the ion filter 146. The cantilevered portion 510 of the sealing ring 508 is long enough to ensure contact with the upper isolator 506 and provide a good downward biasing force. Thus, the sealing ring 508 and the upper isolator 506 effectively seal the volume 512 between the gas distribution plate 158, the ion filter 146, the upper isolator 506, and the spacer ring 180. The volume 512 is essentially a dead volume to contain gases, such as purge gas, and to prevent TiCl from migrating into the volume 512. Figure 5 and Figure 6 The dashed arrows in FIG also illustrate potential purge loss paths for purge gas that manages to escape volume 512. Such purge gas can flow between seal ring 508 and upper isolator 506, and between upper isolator 506 and ion filter 146. Furthermore, such purge gas can flow between lower isolator 142 and ion filter 146, and between lower isolator 142 and sidewall 106.

[0052] like Figure 5 As shown, in some embodiments, the spacer ring 180 may have a circular cross-section. Figure 6 As shown, in some embodiments, the spacer ring 180 can have an oval cross-section, such as a rectangle with rounded corners. Other shapes can also be used to control the surface area contact between the spacer ring 180 and either or both of the gas distribution plate 158 and the ion filter 146.

[0053] Figure 7is a schematic side view of a portion of a showerhead assembly 700 , according to at least some embodiments of the present disclosure. Figure 8 yes Figure 7 An isometric cross-sectional view of a portion of a showerhead assembly 700 . Figure 7 and Figure 8 Depicts a similar Figure 5 and Figure 6 A specific embodiment of the spray head assembly 700 is depicted, but in a solid model view showing more detail. Figure 8 As best seen in FIG. 1 , the first channel 502 extends through the heater plate 148 (near the periphery and shown in cross-section). The first channel 502 is aligned with an annular channel 704 formed in the upper surface of the gas distribution plate 158. A plurality of through holes 706 are formed in the gas distribution plate 158 between a bottom surface 708 of the annular channel 704 and a bottom 710 of the gas distribution plate 158, positioned proximate the spacer ring 180 and facing the ion filter 146 (e.g., along the gap 174, as shown). Figure 1 ). Similar to Figure 5 and Figure 6 The spray head assemblies 500 and 600 shown in FIG. Figure 7 and Figure 8 The sealing ring 508 in the upper isolator 506 is fastened to the gas distribution plate 158 , for example, with screws or bolts (not shown), and the sealing ring 508 pushes downward and seals the upper isolator 506 .

[0054] A gas, such as a purge gas or a cleaning gas, may be provided via the first passage 502 to flow into the annular passage 704. The gas fills the annular passage 704 and flows through the plurality of through-holes 706 into the gap 174 between the gas distribution plate 158 and the ion filter 146, adjacent to the spacer ring 180. The gas then flows primarily radially inward along the gap 174 to a remote cavity (e.g., a second plenum) 162 formed between the gas distribution plate 158 and the ion filter 146. Any gas flowing toward or around the spacer ring 180 (e.g., between the spacer ring 180 and the gas distribution plate 158, between the spacer ring 180 and the ion filter 146, and / or through gaps, such as the aforementioned gap 184) and into the volume 512 (which essentially forms a stagnant volume filled with gas) effectively prevents TiCl from reaching the volume 512 and being deposited on surfaces of components defining the volume 512, such as the surfaces of the gas distribution plate 158, the ion filter 146, the spacer ring 180, and the upper isolator 506.

[0055] Figure 9 is a schematic side view of a portion of a showerhead assembly 900 , according to at least some embodiments of the present disclosure. Figure 10 yes Figure 9An isometric cross-sectional view of a portion of a sprinkler head assembly. Figure 9 and Figure 10 FIG shows a specific embodiment of the nozzle assembly 900, which is similar to the above reference embodiment. Figure 7 and Figure 8 The specific embodiments described are similar, but with some differences. Figure 10 As best shown, the sealing ring 508 can extend between the heater plate 148 and the ion filter 146, and the bottom surface of the heater plate 148 can include an annular channel 904, wherein the first channel 502 terminates in the annular channel 904 of the heater plate 148. The annular channel 904 of the heater plate 148 is aligned with the annular channel 704 of the gas distribution plate 158. A plurality of through-holes 906 can be provided in the sealing ring 508 between the annular channel 904 of the heater plate 148 and the annular channel 704 of the gas distribution plate 158. The annular channel 904 of the heater plate 148 forms a first plenum 908 for distributing gas around the heater plate 148 before flowing through the sealing ring 508 to the annular channel 704 of the gas distribution plate 158. The annular channel 704 of the gas distribution plate 158 forms a second plenum 910, wherein the gas is further distributed before flowing through the plurality of through-holes 706 in the gas distribution plate 158 and reaching the gap 174. Providing multiple plenums (eg, first plenum 908 and second plenum 910 ) facilitates a more uniform distribution of gas provided to gap 174 .

[0056] Same as Figure 9 and Figure 10 As shown, but may be provided in embodiments without multiple plenums as described above, upper isolator 506 may include an angled upper surface 912 that slopes downwardly and inwardly. Upper isolator 506 also defines a contact point 914 on the angled upper surface for contacting seal ring 508. Contact point 914 is positioned proximate to the radially outer edge of seal ring 508 to maximize the biasing force against upper isolator 506 and improve sealing of volume 512.

[0057] Figure 11 is a schematic side view of a portion of a showerhead assembly 1100 , in accordance with at least some embodiments of the present disclosure. Figure 11 Depicted with reference to above Figure 9 and Figure 10 A similar embodiment of the showerhead assembly 1100 is described, but with some differences. Figure 11 As best shown, sealing ring 508 is secured to heater plate 148 and extends to seal upper isolator 506, thereby defining volume 512 between sealing ring 508, spacer ring 180, gas distribution plate 158, heater plate 148, upper isolator 506, and ion filter 146. Sealing ring 508 reduces leakage from volume 512 to purge volume 191.

[0058] The heater plate 148 may also include a first channel 502 having an annular channel 904 along the bottom of the heater plate 148. The annular channel 904 of the heater plate 148 is aligned with the annular channel 704 of the gas distribution plate 158. Below the sealing ring 508, a sealing ring 1104 extends between the bottom of the heater plate 148 and the top of the gas distribution plate 158. The sealing ring 1104 includes a plurality of holes 1102 to allow gas flow between the annular channel 904 and the annular channel 704. The sealing ring 1104 may be a metal seal that seals the annular channels 907 and 704 from the first plenum 160. The sealing ring 1104 and the sealing ring 508 may be made of the same material.

[0059] A plurality of through holes 706 are formed in the gas distribution plate 158 between the bottom surface 708 of the annular channel 704 and a position above the bottom 710 of the gas distribution plate 158. A plurality of radial holes 1106 are formed in the gas distribution plate 158 extending radially outward from the second channel 504 to connect the through holes 706 with the gap 174. In some embodiments, as shown in FIG. Figure 11 As shown, the holes 1106 may be located below the spacer ring 180 and above the bottom 710 of the gas distribution plate 158 .

[0060] The ion filter 146 includes a plurality of through-holes 1114 near the periphery of the ion filter 146. The through-holes 1114 allow gas (e.g., purge gas) in the gap 174 to flow into the processing volume 178 and the pumping ring 126, which can reduce the concentration of precursors in the center of the remote chamber (e.g., the second plenum) 162.

[0061] Same as Figure 11 As shown, but may be provided in other embodiments, a metal sealing ring 1108 may extend between the bottom of the lower isolator 142 and the top of the pumping ring 126 to close the opening 1112 in the pumping ring 126 and block the flow of gas between the bottom of the lower isolator 142 and the top of the pumping ring 126 to prevent TiCl4 back diffusion and short circuiting of the direct plasma. The opening 1112 is closed to direct gas (e.g., purge gas) entering the processing volume 178 (through hole 1114 or between the ion filter 146 and the lower isolator 142) into the opening 1110 in the pumping ring 126.

[0062] Thus, due to the configuration of the showerhead assembly and processing chamber according to the present disclosure, metal vapor may be prevented from reaching surfaces of the defined volume 512 by a strong purge (eg, an argon purge), thereby reducing metal coating of such surfaces that could cause unwanted shorts.

[0063] Figure 12is a schematic side view of a portion of a showerhead assembly 1200 , according to at least some embodiments of the present disclosure. Figure 12 Depicted with reference to above Figure 11 The embodiment of the showerhead assembly 1100 is similar to that described above, but with some differences. The showerhead assembly 1200 omits the sealing ring 508 and the sealing ring 1104. In some embodiments, such as Figure 12 As shown, showerhead assembly 1200 includes a spacer ring 180 having a generally T-shaped profile, an upper sealing ring 1202, and a lower sealing ring 1204. Spacer ring 180 may have an upper shoulder 1206 that extends to seal against upper isolator 506. Spacer ring 180 may have a lower shoulder 1208 that extends to seal against ion filter 146. Upper sealing ring 1202 may be positioned in space 1203 defined by upper shoulder 1206, upper isolator 506, and gas distribution plate 158. Lower sealing ring 1204 may be positioned in space 1205 defined by lower shoulder 1208 and ion filter 146. Space 1203 is sealed by upper sealing ring 1202, and space 1205 is sealed by lower sealing ring 1204.

[0064] In some embodiments, the upper sealing ring 1202 and the lower sealing ring 1204 may be formed as compliant metal sealing rings, which may be made of a thermally conductive material (e.g., nickel) that is compatible with chemical processing. Figure 12 As shown, the upper seal ring 1202 and the lower seal ring 1204 are a single piece and may have a channel profile (eg, a C-shaped channel).

[0065] In some specific embodiments, Figure 12 As shown, the spacer ring 180 is formed as a single piece and can be formed from the same material (e.g., aluminum nitride) as described above for the spacer ring 180. In some embodiments, the spacer ring 180 is an insulator of a high conductivity material (e.g., aluminum nitride) that provides insulation between the gas distribution plate 158 and the ion filter 146.

[0066] The upper seal ring 1202 and the lower seal ring 1204 are configured to allow for thermal expansion (e.g., radially) of the gas distribution plate 158 and the ion filter 146. When operating at elevated process temperatures during plasma processing, the thermal expansion of the gas distribution plate 158 will cause the gas distribution plate 158 to compress the upper seal ring 1202 against the upper shoulder 1206 of the spacer ring 180, thereby forming a seal. Furthermore, when operating at elevated process temperatures, the thermal expansion of the ion filter 146 will cause the ion filter 146 to compress the lower seal ring 1204 against the lower shoulder 1208 of the spacer ring 180, thereby forming a seal. In some embodiments, the upper seal ring 1202 and the lower seal ring 1204 may permanently deform when compressed and, therefore, may be replaced after the plasma processing is completed.

[0067] In some embodiments, at elevated processing temperatures, ion filter 146 and gas distribution plate 158, which may be made of nickel, expand more than spacer ring 180, which may be made of aluminum nitride. Due to the differential expansion, spaces 1203 and 1205 may be significantly reduced, resulting in compression of upper and lower seal rings 1202 and 1204. The compression of upper and lower seal rings 1202 and 1204 results in sealing spaces 1203 and 1205, thereby creating a very effective annular purge volume formed by the purge gas (e.g., an inert gas such as argon) flowing from aperture 1106. Additionally, in embodiments where upper and lower seal rings 1202 and 1204 are formed of metal, the metal seals, formed of a highly thermally conductive metal, can also transfer significant heat from gas distribution plate 158 to ion filter 146, thereby maintaining ion filter 146 well above the temperature at which TiCl radicals can condense during plasma processing.

[0068] When the upper seal ring 1202 and the lower seal ring 1204 are compressed, the gap 174 between the gas distribution plate 158 and the spacer ring 180, between the gas distribution plate 158 and the ion filter 146, and between the ion filter 146 and the spacer ring 180 can be about 0.8 mm. When operating at elevated processing temperatures during plasma processing, a purge gas (e.g., argon) can flow through the holes 706 and the holes 1106 so that a portion of the purge gas will flow into the gap 174 and into the upper seal ring 1202 and the lower seal ring 1204, thereby preventing back diffusion of process gas into the gap 174 and preventing metal vapor from reaching surfaces of the spacer ring 180, the gas distribution plate 158, and the ion filter 146 that extend along the gap 174, thereby reducing the presence of metal coatings on such surfaces that could cause undesirable short circuits.

[0069] While the foregoing relates to specific embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope of the foregoing.

Claims

1. A nozzle assembly for a processing chamber, the nozzle assembly comprising: a heated showerhead having a heater plate and a gas distribution plate coupled to the heater plate; an ion filter spaced apart from the heated showerhead; a spacer ring, the spacer ring being between the heated showerhead and the ion filter; a remote plasma region defined between the heated showerhead and the ion filter; a first gap located on a radially inner side of the spacer ring, disposed between the gas distribution plate and the ion filter or between the heated showerhead and the ion filter, the first gap being in fluid communication with the remote plasma region; a first passage extending through the heater plate; and A second channel is in communication with the first channel and extends through the gas distribution plate, the second channel extending to the first gap.

2. The showerhead assembly of claim 1, wherein the first gap is disposed between the gas distribution plate and the ion filter, and wherein the spacer ring comprises a plurality of elements that are circumferentially spaced apart from each other by a second gap of 0.5 mm to 0.7 mm.

3. The showerhead assembly of claim 1, wherein the first gap is provided between the gas distribution plate and the ion filter, wherein the spacer ring is formed as a single piece, and the first gap is 0.5 to 0.7 mm.

4. A nozzle assembly as described in claim 3, wherein the spacer ring has an upper shoulder and a lower shoulder, and the nozzle assembly further includes an upper sealing ring and a lower sealing ring, the upper sealing ring is located in a space at least partially defined by the upper shoulder and the gas distribution plate, and the lower sealing ring is located in a space at least partially defined by the lower shoulder and the ion filter.

5. The showerhead assembly according to any one of claims 1 to 4, wherein the first gap is disposed between the gas distribution plate and the ion filter, and the showerhead assembly further comprises: an upper separator, the upper separator being spaced apart from the spacer ring and supported on a portion of the ion filter radially outside the spacer ring; a sealing ring secured to the heated showerhead that seals against the upper separator and pushes the upper separator against the ion filter; and A volume is defined by the heated showerhead, the ion filter, the seal ring, the upper separator, and the spacer ring, wherein the volume is in fluid communication with the first gap.

6. A nozzle assembly as described in any one of claims 1 to 4, wherein the first gap is arranged between the gas distribution plate and the ion filter, and wherein the second channel includes an annular channel and a plurality of through holes, the annular channel is aligned with the first channel and is formed in the upper surface of the gas distribution plate, and the plurality of through holes are formed between the bottom surface of the annular channel in the gas distribution plate and the bottom or side of the gas distribution plate close to the gap.

7. The showerhead assembly of claim 6, wherein the first channel comprises an annular channel formed in a bottom surface of the heater plate and aligned with the annular channel formed in the upper surface of the gas distribution plate.

8. The spray head assembly according to claim 7, further comprising: an upper separator spaced apart from the spacer ring and supported on a portion of the ion filter radially outside the spacer ring; and A sealing ring secured to the heated showerhead seals against the upper isolator and pushes the upper isolator against the ion filter, wherein the sealing ring extends between the heater plate and the gas distribution plate and includes a portion having a through hole extending between the first channel and the second channel.

9. The sprayhead assembly of claim 8, wherein the upper isolator includes an angled upper surface that slopes downwardly and radially inwardly and defines a contact point on the angled upper surface for contacting the seal ring.

10. The showerhead assembly of any one of claims 1 to 4, wherein the first gap is disposed between the gas distribution plate and the ion filter, and wherein the ion filter comprises a plurality of through holes located below the second channel along a periphery of the ion filter.

11. The showerhead assembly of claim 1, wherein the first gap is disposed between the heated showerhead and the ion filter.

12. A nozzle assembly as described in claim 11, wherein the second channel includes an annular channel and a plurality of through holes, the annular channel is aligned with the first channel and is formed in the upper surface of the gas distribution plate, and the plurality of through holes are formed between the bottom surface of the annular channel in the gas distribution plate and the bottom of the gas distribution plate near the first gap.

13. The showerhead assembly of claim 12, wherein the first channel comprises an annular channel formed in a bottom surface of the heater plate and aligned with the annular channel formed in the upper surface of the gas distribution plate.

14. The spray head assembly of claim 13, wherein the spacer ring is formed as a single piece.

15. The showerhead assembly of any one of claims 11 to 14, wherein the gas distribution plate includes a plurality of holes extending radially outward from the second channel, and wherein the ion filter includes a further plurality of through holes along a periphery of the ion filter beneath the second channel.

16. The showerhead assembly of any one of claims 11 to 14, wherein the spacer ring has a lower shoulder in contact with the ion filter and has an upper shoulder, and the showerhead assembly further comprises: an upper isolator supported on the upper shoulder of the spacer ring; an upper sealing ring located in a space between the upper isolator, the upper shoulder, and the gas distribution plate; and A lower sealing ring is in the space between the lower shoulder and the ion filter.

17. A processing chamber, the processing chamber comprising: a chamber body having an interior volume; a substrate support disposed within the interior volume; and A showerhead assembly is disposed in the interior volume opposite the substrate support, wherein the showerhead assembly is as described in any one of claims 1-4 or 11-14.

18. The processing chamber of claim 17, further comprising: a lower spacer supporting the ion filter, the ion filter being spaced above the substrate support; and A pumping ring supports the lower isolator, wherein the lower isolator is at least partially disposed between the ion filter and the pumping ring, wherein a second gap is defined between the lower isolator and the ion filter, and wherein the pumping ring has a fluid channel in fluid communication with the second gap.

19. The processing chamber of claim 18, wherein the ion filter comprises a plurality of through holes along a periphery of the ion filter, wherein the plurality of through holes in the ion filter are configured to direct the purge gas around the substrate support toward the fluid channel of the pumping ring.

20. The processing chamber of claim 17, wherein the chamber body comprises a lid coupled to the showerhead assembly, the chamber body further comprising a gas conduit extending between the lid and the heated showerhead, wherein the gas conduit supplies a purge gas to the first channel and the second channel.

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