Advanced coating methods and materials to prevent arcing in hdp-cvd chambers

Abstract

Embodiments described herein relate to apparatuses and coating methods to reduce arcing in a chamber (e.g., in HDP-CVD, PECVD, PE-ALD, and etch chambers). The apparatuses include an annular gas distributor for in-situ deposition of a coating material, and a processing chamber including the annular gas distributor. The annular gas distributor includes an annular body having at least one gas inlet disposed on a first side of the annular body and a plurality of gas distribution ports disposed on a first surface of the annular body. The plurality of gas distribution ports are arranged in a plurality of evenly distributed rows. The plurality of gas distribution ports in a first row of the plurality of evenly distributed rows are adapted to direct gas at a different exit angle than the plurality of gas distribution ports in a second row of the plurality of evenly distributed rows.

Description

[0001] This application is a divisional application of the patent application with application number 201680025485.7, filed on October 26, 2016, and titled "Advanced coating methods and materials to prevent arcing in HDP-CVD chambers". TECHNICAL FIELD

[0002] Embodiments of the present disclosure generally relate to devices and coating methods to reduce arcing in HDP-CVD chambers. BACKGROUND

[0003] High density plasma chemical vapor deposition (HDP-CVD) employs an inductively coupled plasma source for generating a higher density plasma at low vacuum pressure. The higher density plasma results in superior gap fill performance, high quality film deposition at lower temperatures, high throughput, and simple operating characteristics. The reactor design and processing techniques of HDP-CVD allow for the deposition of both undoped and doped films for a wide range of applications, including shallow trench isolation (STI), pre-metal dielectric layer (PMD), interlayer dielectric (ILD) layer, intermetallic dielectric (IMD) layer, and passivation. Thus, HDP-CVD is widely used in the semiconductor industry.

[0004] Due to the low processing pressure, one of the key problems reported in HDP-CVD chambers is chamber arcing. Arcing occurs when a highly concentrated electric field (E-field) at a sharp point causes the dielectric to break down at the metal chamber walls, gas ring, and cathode body. The high discharge current that occurs over a small area evaporates the exposed metal and contaminates the substrate surface, resulting in a reduction in process yield.

[0005] Various techniques have been proposed to reduce chamber arcing. For example, an external coating method can be applied on new chambers (pre-installation). However, when the pre-installed coating is broken during shipping, installation, or maintenance, or once the coating becomes too thin, the coating must be reapplied. A seasoning layer can be deposited on the metal chamber surfaces during a seasoning operation after chamber cleaning to mitigate arcing. However, conventional seasoning layers provide insufficient coverage on the chamber components, and thus, the problem of chamber arcing remains.

[0006] Therefore, there is a need for improved devices and coating methods to reduce arcing in HDP-CVD chambers. SUMMARY

[0007] In one embodiment, an annular gas distributor is disclosed. The annular gas distributor includes an annular body having at least one gas inlet disposed on a first side of the annular body and a plurality of gas distribution ports disposed on a first surface of the annular body. The plurality of gas distribution ports are arranged in a plurality of evenly distributed rows. A first gas distribution port of the plurality of gas distribution ports in a first row of the plurality of evenly distributed rows is adapted to direct gas at a different exit angle than a second gas distribution port of the plurality of gas distribution ports in the first row of the plurality of evenly distributed rows. In another embodiment, a processing chamber is disclosed. The processing chamber includes a chamber body and a dome assembly disposed on the chamber body, a substrate support positioned in the chamber body, a gas inlet mounted on the dome assembly, and an annular gas distributor. The annular gas distributor includes an annular body and a plurality of gas distribution ports disposed on a first surface of the annular body.

[0008] In yet another embodiment, a method is disclosed. The method includes the steps of flowing a first precursor into a processing chamber through a first gas inlet, ionizing the first precursor, flowing a second precursor into the processing chamber through an annular body adapted to distribute the second precursor, the second precursor being different than the first precursor, ionizing the second precursor, and depositing a seasoning process material on an interior surface of the processing chamber from the ionized second precursor. BRIEF DESCRIPTION OF DRAWINGS

[0009] A more particular description of the disclosure briefly described in the foregoing summary will be rendered by reference to the implementations, of which some are illustrated in the drawings wherein like reference numerals are used to indicate like parts throughout the several views. It is appreciated that the drawings are only for purposes of illustrating example implementations and are not to be taken as limiting the scope of the disclosure, as the disclosure can admit to other and / or equally effective implementations.

[0010] Figure 1 is a schematic view of a processing chamber in accordance with one embodiment described herein.

[0011] Figure 2 is a schematic view of an annular gas distributor in accordance with one embodiment described herein.

[0012] Figure 3 is a flow diagram illustrating a method in accordance with one embodiment described herein.

[0013] Figure 4A is a schematic view of a portion of a processing chamber in accordance with another embodiment described herein.

[0014] Figure 4B is a schematic cross-sectional view of an annular gas distributor in accordance with another embodiment described herein.

[0015] To facilitate an understanding of this description, like reference characters are used throughout the discussion to identify like elements. It is intended that individual elements, as well as features of the embodiments, can be combined with or substituted for other elements and features in other embodiments. DETAILED DESCRIPTION

[0016] Embodiments described herein relate to apparatuses and coating methods to reduce chamber arcing, for example, in HDP-CVD, PECVD, PE-ALD, and etch chambers. The apparatuses include an annular gas distributor for in-situ deposition of a coating material, and a processing chamber including the annular gas distributor. The annular gas distributor can include one or more gas inlets and a plurality of gas distribution ports. The annular gas distributor can be positioned in a lower portion of a processing chamber, such as a plasma enhanced chemical vapor deposition (PECVD) chamber, to provide a precursor gas to the lower portion of the processing chamber for depositing a seasoning process material. Embodiments described herein also include methods for seasoning a processing chamber. The methods include the steps of flowing a first precursor into the processing chamber through a first gas inlet, and flowing a seasoning process precursor into the processing chamber through the annular gas distributor. The first and second precursors can be ionized and reacted to deposit a seasoning process material in the processing chamber.

[0017] Figure 1 is a schematic view of a processing chamber 100 in accordance with one embodiment described herein. In one example, the processing chamber 100 can be a high density plasma chemical vapor deposition (HDP-CVD) system. The processing chamber 100 includes a chamber body 116, a substrate support 106, and an arch cover assembly 115 including an arch 102, an inductive assembly 112, and a temperature control plate 110. The arch 102 is positioned on the chamber body 116. The arch 102 and the chamber body 116 define an interior space of the processing chamber 100. The substrate support 106 is positioned within the interior space of the processing chamber 100 and supports a substrate 190 on the substrate support 106 during processing. A substrate support arm 108 is coupled to the substrate support 106 to facilitate support and actuation of the substrate support 106. An actuator 134 is coupled to the substrate support arm 108 via a bellows 136. The actuator 134 actuates the substrate support arm 108 and the substrate support 106 coupled thereto vertically to facilitate substrate transfer between a substrate transfer robot (not shown) and the substrate support 106 during substrate transfer processing.

[0018] The dome 102 defines an upper boundary of a plasma processing region 104 positioned within the processing chamber 100. The dome 102 can be fabricated from a ceramic dielectric material, such as aluminum, aluminum oxide, or aluminum nitride. A lower boundary of the plasma processing region 104 is defined by an upper surface of the substrate support 106. During processing, a plasma or other ionized gas can be generated within the plasma processing region 104 to facilitate processing of the substrate 190. For example, a plasma can be generated in the plasma processing region 104 to deposit material on the substrate 190 in an HDP-CVD, plasma enhanced chemical vapor deposition (PECVD), or plasma enhanced atomic layer deposition (PE-ALD) process.

[0019] An inductive assembly 112 including one or more inductive coils 114 is positioned on the dome 102 to facilitate plasma generation in the plasma processing region 104. A power source (not shown) can be coupled to the inductive assembly 112 to provide power to the one or more inductive coils 114. During operation, the plurality of inductive coils 114 can provide radio frequency (RF) power to one or more precursor or process gases positioned within the plasma processing region 104 to ionize the precursor or process gases. In one example, the plurality of inductive coils 114 can provide up to 5,000 watts of RF power at 2 MHz. The operating frequency of the plurality of inductive coils 114 can be shifted from the nominal operating frequency to improve plasma generation efficiency. A temperature control plate 110 is positioned on the inductive assembly 112 and is thermally coupled to the dome 102 via the inductive assembly 112. The temperature control plate 110 allows the dome temperature to be controlled to within about ±10°C of a range of about 100°C to 200°C. The temperature control plate 110 facilitates optimization of the dome temperature for various processes. In one example, a liquid coolant can be flowed through the inductive coils 114 to facilitate cooling of the inductive coils in addition to or as an alternative to temperature control provided by the temperature control plate 110.

[0020] The processing chamber 100 includes a gas panel 130 adapted to store one or more precursors or process gases utilized during processing (e.g., HDP-CVD, PECVD, or PEALD processing). Precursors or process gases can be introduced into the plasma processing region 104 via one or more gas inlets 128 (both shown as 128a, 128b) mounted to the dome assembly 115. The one or more gas inlets 128a, 128b are coupled to the gas panel 130 via one or more gas supply lines 132 (one of which is shown). In one embodiment, the one or more gas inlets 128 can be configured as a single gas ring. In another embodiment, the one or more gas inlets 128 can be configured as a top shutter. Process gases (e.g., precursor gases or other gases used during processing, or reaction byproducts in the processing chamber) can be exhausted from the processing chamber 100 by a pumping system 122. The pumping system 122 is engaged to a lower portion of the processing chamber 100 and includes a throttle valve 124 and a pump 126. The throttle valve 124 couples the pump 126 to the chamber body 116. The throttle valve 124 can be actuated to control chamber pressure by limiting the rate of exhaust flow out of the processing chamber 100 via the pump 126.

[0021] A ring-shaped gas distributor 118 is positioned in a lower portion of the chamber body 116 between the throttle valve 124 and the substrate support 106. The ring-shaped gas distributor 118 includes a hollow tubular ring having one or more gas inlets and gas distribution ports to distribute process or precursor gases in the lower portion of the processing chamber 100. The ring-shaped gas distributor 118 can be attached to the inner surface 105 of the chamber body 116 by an attachment 120. The attachment 120 can be a spring-loaded clamp, bracket, fastener, or the like. Precursor or process gases are supplied to the ring-shaped gas distributor 118 from a second gas panel 140 via a gas supply line 138. The gas supply line 138 can be routed via a bellows 136 adjacent the substrate support arm 108. Alternatively, the gas supply line 138 can be routed via the gas inlets 128a, 128b.

[0022] A process gas (e.g., a precursor gas or other gas used during processing) is supplied from the second gas panel 140 to the annular gas distributor 118, which is distributed in the lower portion of the processing chamber 100 to facilitate formation of a seasoning process layer on the inner surface 105 of the chamber body 116. The annular gas distributor 118 is adapted to distribute gas uniformly into the lower portion of the processing chamber 100 to form a more uniform seasoning process layer than conventional methods, thus reducing the likelihood of undesirable arcing. The annular gas distributor 118 can have a diameter that is less than the diameter of the inner surface 105 of the chamber body 116. In one example, the annular gas distributor can have a diameter that is about 3 percent to about 20 percent less than the diameter of the inner surface 105. The annular gas distributor 118 can be fabricated from a metal, a metal alloy, or a ceramic material. In one embodiment, the annular gas distributor 118 is fabricated from the same material as the chamber body 116 so as to prevent metal contamination. In another embodiment, the annular gas distributor 118 can be fabricated from aluminum oxide. In another embodiment, the annular gas distributor 118 can be fabricated from aluminum nitride. In yet another embodiment, the annular gas distributor 118 can be fabricated from aluminum.

[0023] Figure 2 A schematic view of the annular gas distributor 118. The annular gas distributor 118 is an annular gas distributor that includes a hollow annular body 250 having two gas inlets 254a and 254b disposed on opposite sides of the annular body and a plurality of gas distribution ports 253 disposed on a first surface of the annular body 250. In one example, the upper half of the annular body 250 can include gas distribution ports 253 to direct gas upward to facilitate seasoning of the inner surface 105 of the processing chamber 100 as shown in FIG. 1. Figure 1 In one embodiment, each of the plurality of gas distribution ports 253 has a diameter of about 0.5 millimeters (mm) to about 3 mm, such as a diameter of about 1 mm.

[0024] The plurality of gas distribution ports 253 can be arranged in a plurality of rows 252a, 252b (two of the plurality of rows are labeled). Row 252a can represent a first row and row 252b can represent a second row. The plurality of rows can be evenly distributed in concentric circles around the circumference of the body 250. Lines have been included between the ports 253 of rows 252a and 252b to illustrate the distribution of the rows in the concentric circles. The ports 253 that make up each row can also be radially aligned with the centerline of the body 250. The plurality of gas distribution ports 253 in the first row 252a are positioned to direct gas exiting at an angle that is different from the exit angle of the adjacent row, for example, the second row 252b. In other words, each row of the plurality of gas distribution ports 252 is adapted to direct gas exiting at an angle that is different from an adjacent row. In another example, the gas distribution ports 253 of a particular row can be grouped in sets of three, where each set of three gas distribution ports has a different gas exit angle. The three different angles can be repeated for each set of three in a single row, for example, row 252a or row 252b. The variation in exit angle between adjacent rows 252a, 252b or between adjacent gas distribution ports 253 can be controlled by the diameter of the first surface of the gas distribution apparatus 218. The relative difference in exit angle can be between about 15 degrees and about 30 degrees. In one embodiment, the spacing between each gas distribution port 253 of the plurality of gas distribution ports 253 is between about 1 centimeter (cm) and about 3 cm, for example, about 1 cm.

[0025] Although Figure 2 One embodiment of the annular gas distributor 118 is illustrated, other embodiments are also contemplated. In another embodiment, the annular gas distributor 118 can include more or less than two gas inlets 254a, 254b. In this example, the gas inlets can be positioned at uniform intervals around the outer circumference of the annular gas distributor 118. Further, it is contemplated that the gas distribution ports 253 can be distributed non-uniformly to affect the gas flow within the processing chamber 100. Also, the adjacent rows 252a, 252b can also be distributed non-uniformly. The non-uniform distribution can compensate for asymmetric features of the processing chamber 100 or differences in the gas flow profile within the processing chamber 100. Also, although the gas distributor 118 is illustrated as having an annular body, it is contemplated that other shapes, for example, an oval shape, can be utilized to affect the gas flow within the processing chamber.

[0026] Figure 3 A flow diagram of a method 360 in accordance with one embodiment described herein is illustrated. To facilitate an understanding of embodiments of the present disclosure, a discussion Figure 1 will now be discussed Figure 3Method 360 can be used to deposit a seasoning process material on the interior surface 105 of the processing chamber 100. The method 360 begins at operation 362. At operation 362, a process gas (e.g., a first precursor) is introduced into the processing chamber 100 via one or both of the gas inlets 128a or 128b. The first precursor can be an oxygen precursor or a nitrogen precursor. Exemplary first precursors include, but are not limited to, water (H2O), ozone (O3), oxygen (O2), nitrogen (N2), and ammonia (NH3). At operation 364, the first precursor is ionized. The ionized first precursor forms a monolayer on the interior surface 105 of the processing chamber 100.

[0027] At operation 366, a second precursor is introduced into the processing chamber 100 via the annular gas distributor 118. The annular gas distributor 118 is used to direct the precursor on chamber portions that are normally inaccessible or insufficiently reached if the second precursor were introduced via the gas inlets 128a, 128b disposed above the substrate support 106 only. The second precursor material can be an aluminum-containing precursor or any other metal-containing precursor. Exemplary second precursors include, but are not limited to, trimethylaluminum (TMA) or aluminum chloride (AlCl3). The second precursor is ionized at operation 368.

[0028] At operation 370, the ionized second precursor is absorbed or reacts with the monolayer of the first precursor formed on the interior surface 105. The absorption or reaction of the second monolayer results in the formation of a seasoning process material on the interior surface 105 of the chamber body 116 of the processing chamber 100. The seasoning process material can include any dielectric material having one or more of the following properties: (1) a high breakdown voltage, e.g., higher than 7 MV / cm; (2) resistance to fluorine (F) radicals; (3) minimal particle contamination; or (4) minimal metal contamination. In one embodiment, the seasoning process material is aluminum oxide (Al2O3). In another embodiment, the seasoning process material is aluminum nitride (AIN). The seasoning process material can be deposited to a thickness that prevents arcing, e.g., between about 0.1 microns and about 10 microns, e.g., between about 1 micron and about 3 microns. In one example, the method 360 can be an ALD process, and the seasoning process material can be deposited at a thickness of between about 5 Angstroms and about 10 Angstroms per deposition cycle. In this example, operations 362-370 are repeated until a desired thickness of the seasoning process material is formed.

[0029] In one example, the method 360 can be a PECVD or PE-ALD process. In a PE-ALD process, radicals are generated by the HDPRF source. PE-ALD occurs at relatively low temperatures, below the relatively low temperature limit (<100°C) of the chamber walls or other chamber components. The method 360 can occur during preventative maintenance, corrective maintenance, or as otherwise needed to ensure that all metal parts (e.g., chamber body) are sufficiently coated to substantially prevent chamber arcing. In one example, the method 360 can occur after a thin film formation process in which a thin film is formed on the substrate 190.

[0030] Figure 4A A schematic view of a portion of a processing chamber 480 according to another embodiment described herein. The processing chamber 480 is generally similar to the processing chamber 100, but includes an annular gas distributor 418 instead of the annular gas distributor 118. The gas distributor 418 is coupled to the chamber body 116. The gas distributor 418 includes a tapered outer sidewall to engage the inner surface 105 of the chamber body 116. In one example, the diameter of the outer sidewall of the gas distributor 418 is larger at the top portion of the gas distributor than at the lower portion of the gas distributor. The degree of taper of the sidewall of the gas distributor 418 can be selected to be the same or similar to the taper of the inner surface 105. In this example, the gas distributor 418 can be held in place via a wedge fit, and thus facilitates quick maintenance or replacement of the gas distributor 418. A precursor or process gas is supplied to the annular gas distributor 418 via the gas supply line 138, which interacts with at least one gas inlet provided on the gas distributor 418. It is contemplated that more than one gas supply line 138 can be utilized.

[0031] Figure 4B A schematic cross-sectional view of an annular gas distributor 418 according to one embodiment. The annular gas distributor 418 has an annular gas distribution body 450. The annular gas distribution body 450 includes a first curved surface 456 and a second planar surface 458. A plurality of gas distribution ports 453a, 453b, and 453c (three shown) are provided on the first curved surface 456 of the annular gas distribution body 450 and are adapted to direct process gas to a location within a processing chamber. The first curved surface 456 of the annular gas distribution body 450 is positioned opposite the second planar surface 458, which engages the chamber body 116. The second planar surface 458 has a height 459 between about 5 mm and about 30 mm. In one example, the first curved surface 456 of the annular gas distribution body 450 can include gas distribution ports 453a, 453b, 453c to direct gas inwardly to facilitate, for example, uniform deposition of a thin film on a substrate 190. Figure 4AThe aging process of the inner surface 105 of the chamber 480 shown in the middle. In one embodiment, each of the plurality of gas distribution ports 453a, 453b, 453c has a diameter of about 0.5 mm to about 3 mm, for example, a diameter of about 1 mm.

[0032] The plurality of gas distribution ports 453a, 453b, 453c can be arranged in a plurality of rows. The rows can be evenly distributed around the annular body 450, for example, evenly distributed around the annular body 450 across the first curved surface 456. Figure 4B The gas distribution ports 453a, 453b, and 453c of the first row can be configured to direct gas exiting at different angles than the second gas distribution port 453b. The third gas distribution port 453c can also be positioned to direct gas exiting at a different angle than the second gas distribution port 453b and different than the first port 453a. Also, in another example, each row of the plurality of gas distribution ports 453a, 453b, 453c can be adapted to direct gas exiting at a different angle than an adjacent row. The variation in exit angle between the gas distribution ports 453a, 453b, 453c can be controlled by the diameter of the first curved surface 456 of the gas distributor 418. The relative difference in exit angle between adjacent gas distribution ports 453a, 453b, 453c can be between about 15 degrees and about 30 degrees. In one embodiment, the spacing between adjacent gas distribution ports 453a, 453b, 453c can be between about 1 cm and about 3 cm, for example, about 1 cm.

[0033] Benefits of the present disclosure include reducing chamber arcing and arcing related defects, and increasing chamber lifetime and reducing maintenance costs by depositing an aging process material in portions of the chamber prone to arcing.

[0034] Although the description herein refers to an HDP-CVD chamber, it is understood that the disclosure herein can also be applied to other semiconductor equipment tools, such as PECVD processing chambers, etch processing chambers, and PE-ALD processing chambers.

[0035] While the foregoing is directed to implementations of the present disclosure, other and further implementations of the disclosure can be devised without departing from the basic scope thereof, and the scope of the present disclosure is determined by the following claims.

Claims

1. An annular gas distributor for distributing a seasoning process gas in a lower portion of a plasma processing chamber below a substrate support of the plasma processing chamber, the annular gas distributor comprising: an annular body having a top portion and a lower portion, an outer sidewall of the annular gas distributor having a larger diameter at the top portion than at the lower portion, the annular body having a flat surface and a curved surface defining a space in the annular body, the flat surface extending from the top portion to the lower portion, the curved surface positioned opposite the flat surface, the flat surface engaging an inner surface of a chamber body of the plasma processing chamber; at least one gas inlet formed through the curved surface of the annular body; and a plurality of gas distribution ports formed through the curved surface of the annular body, the plurality of gas distribution ports arranged in a plurality of evenly distributed rows, wherein the plurality of gas distribution ports in a first row of the plurality of evenly distributed rows are adapted to direct gas at a different exit angle than the plurality of gas distribution ports in a second row of the plurality of evenly distributed rows, and at least one of the gas distribution ports is configured to direct gas outward relative to a centerline of the annular gas distributor.

2. The annular gas distributor of claim 1, wherein the plurality of gas distribution ports distribute the gas radially inward from the flat surface.

3. The annular gas distributor of claim 1, wherein the plurality of evenly distributed rows are evenly distributed across the curved surface.

4. The annular gas distributor of claim 1, wherein the at least one gas inlet is formed through the curved surface adjacent to the flat surface to inject the gas into the space parallel to the flat surface.

5. The annular gas distributor of claim 1, wherein the annular body comprises a material selected from the group consisting of: aluminum, aluminum oxide, and aluminum nitride.

6. The annular gas distributor of claim 1, wherein each of the plurality of gas distribution ports has a diameter between about 0.5 millimeters and about 3 millimeters.

7. The annular gas distributor of claim 1, wherein a length of the flat surface from the top portion to the lower portion is between about 5 mm and about 30 mm.

8. An annular gas distributor for distributing a gas for depositing a seasoning process material in a lower portion of a plasma processing chamber below a substrate support of the plasma processing chamber, the annular gas distributor comprising: ​ an annular body having a top portion and a lower portion, an outer sidewall of the annular gas distributor having a larger diameter at the top portion than the lower portion, the annular body having a flat and a curved surface defining a space in the annular body, the flat extending from the top portion to the lower portion, the curved surface positioned opposite the flat, the flat engaging an inner surface of a chamber body of the plasma processing chamber; at least one gas inlet formed through the curved surface of the annular body; and a plurality of gas distribution ports formed through the curved surface of the annular body, wherein the plurality of gas distribution ports are arranged in a plurality of evenly distributed rows, and wherein the plurality of gas distribution ports in a first row of the plurality of evenly distributed rows are adapted to direct gas at a different exit angle than the plurality of gas distribution ports in a second row of the plurality of evenly distributed rows, at least one of the gas distribution ports configured to direct gas outward relative to a centerline of the annular gas distributor, and a change in exit angle between adjacent rows of the plurality of evenly distributed rows is between 15 degrees and 30 degrees.

9. The annular gas distributor of claim 8, wherein the plurality of evenly distributed rows are evenly distributed across the curved surface.

10. The annular gas distributor of claim 8, wherein the at least one gas inlet is formed through the curved surface adjacent to the flat to inject the gas into the space parallel to the flat.

11. The annular gas distributor of claim 8, wherein the annular body comprises a material selected from the group consisting of: aluminum, aluminum oxide, and aluminum nitride.

12. The annular gas distributor of claim 8, wherein each of the plurality of gas distribution ports has a diameter between about 0.5 millimeters and about 3 millimeters.

13. The annular gas distributor of claim 8, wherein a length of the flat from the top portion to the lower portion is between about 5 mm and about 30 mm.

14. An annular gas distributor for distributing a seasoning process gas in a lower portion of a plasma processing chamber below a substrate support of the plasma processing chamber, the annular gas distributor comprising: an annular body having a top portion and a lower portion, an outer sidewall of the annular gas distributor having a larger diameter at the top portion than the lower portion, the annular body having a flat and a curved surface defining a space in the annular body, the flat extending from the top portion to the lower portion, the curved surface positioned opposite the flat, the flat engaging an inner surface of a chamber body of the plasma processing chamber; at least one gas inlet formed through the curved surface of the annular body; and a plurality of gas distribution ports formed through the curved surface of the annular body, wherein the plurality of gas distribution ports are arranged in a plurality of evenly distributed rows, and wherein the plurality of gas distribution ports in a first row of the plurality of evenly distributed rows are adapted to direct gas at a different exit angle than the plurality of gas distribution ports in a second row of the plurality of evenly distributed rows, at least one of the gas distribution ports configured to direct gas outward relative to a centerline of the annular gas distributor, and a change in exit angle between adjacent rows of the plurality of evenly distributed rows is between 15 degrees and 30 degrees. a plurality of gas distribution ports formed through the curved face of the annular body, the plurality of gas distribution ports arranged in a plurality of rows, wherein the plurality of gas distribution ports in a first row of the plurality of rows are adapted to direct gas at a different exit angle than the plurality of gas distribution ports in a second row of the plurality of rows.

15. The annular gas distributor of claim 14, wherein the change in exit angle between adjacent rows of the plurality of rows is between 15 degrees and 30 degrees.

16. The annular gas distributor of claim 14, wherein the plurality of rows are uniformly distributed rows.

17. The annular gas distributor of claim 14, wherein the annular body comprises aluminum.

18. The annular gas distributor of claim 14, wherein the at least one gas inlet is formed through the curved face adjacent to the plane to inject the gas into the space parallel to the plane.

19. The annular gas distributor of claim 18, wherein the plurality of gas distribution ports are in fluid communication with the space and an area outside of the annular body.

20. The annular gas distributor of claim 14, wherein two gas inlets are provided on opposite sides of the annular body.

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