Substrate Halo Placement for Improved Process Uniformity

Abstract

1. A substrate holder assembly comprising: a substrate platen arranged to support a substrate at a substrate location; a halo ring arranged around the substrate location; and an outer halo arranged around the halo ring and defining a first aperture, wherein the outer halo is arranged to engage the halo ring, the halo ring is at least partially disposed within the first aperture, and the halo ring defines a second aperture concentrically disposed within the first aperture, and the outer halo and the halo ring are formed at least in part from silicon, silicon carbide, doped silicon, quartz, and ceramic.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority to U.S. Non - Provisional Patent Application No. 17 / 329,883, filed on May 25, 2021, the entire contents of which are incorporated herein by reference.

[0002] Embodiments of the present disclosure relate to semiconductor workpiece processing, and more particularly, to semiconductor workpiece processing using a substrate halo for process uniformity.

Background Art

[0003] In plasma - assisted and ion - beam - assisted device processing, the goal is often to produce process uniformity across a substrate. Substrates, such as semiconductor wafers, are often arranged to be surrounded by hardware, such as a halo, to protect process chambers, substrates, or other components that are not designed to receive plasma or ion - beam processing. Most of the substrate can receive relatively uniform processing, but the presence of edge effects near the periphery of the substrate is frequently observed, and edge effects can include non - uniform process results, as well as contamination, particle generation, and other undesirable results.

[0004] In view of these and other considerations, the present disclosure is provided.

Summary of the Invention

[0005] In one embodiment, a substrate assembly may include an outer halo, the outer halo comprising a first material and defining a first aperture. A substrate holder may include a halo ring, the halo ring comprising a second material and disposed at least partially within the first aperture. The halo ring may define a second aperture concentrically disposed within the first aperture, and the halo ring is coupled therein to receive a substrate.

[0006] A substrate assembly according to an exemplary embodiment of the present disclosure may include an outer halo defining a first aperture, and a halo ring disposed at least partially within the first aperture, the halo ring defining a second aperture concentrically disposed within the first aperture, and the halo ring being coupled to receive a substrate therein, wherein the outer halo and the halo ring are formed at least partially from one of silicon, silicon carbide, doped silicon, quartz, and ceramic.

[0007] A substrate holder assembly according to an exemplary embodiment of the present disclosure may include a substrate platen disposed to support a substrate at a substrate location, a halo ring disposed around the substrate location, and an outer halo disposed around the halo ring and defining a first aperture, wherein the outer halo is disposed to engage the halo ring, the halo ring is disposed at least partially within the first aperture, the halo ring defines a second aperture concentrically disposed within the first aperture, and the outer halo and the halo ring are formed at least partially from silicon, silicon carbide, doped silicon, quartz, and ceramic.

[0008] A processing apparatus according to an exemplary embodiment of the present disclosure may include a process chamber and a substrate holder assembly disposed within the process chamber, the substrate holder assembly including a substrate platen disposed to support a substrate at a substrate location, a halo ring disposed around the substrate location, and an outer halo disposed around the halo ring and configured to engage the halo ring, wherein the outer halo and the halo ring are formed at least partially from silicon, silicon carbide, doped silicon, quartz, and ceramic.

[0009] The accompanying drawings illustrate exemplary ways of the present disclosure, including practical applications of the principles of the present disclosure, as follows.

Brief Description of the Drawings

[0010]

Figure 1A

Figure 1B

Figure 1C

Figure 2A

Figure 2B

Figure 2C

Figure 3

[0011] The drawings are not necessarily to scale. The drawings are merely illustrative and do not depict specific parameters of the present disclosure. The drawings show exemplary embodiments of the present disclosure and should not be construed as limiting the scope. In the drawings, like numerals represent like elements.

Embodiments for Carrying Out the Invention

[0012] Next, with reference to the accompanying drawings, in which several embodiments are shown, this embodiment will be more fully described below. The subject matter of the present disclosure can be embodied in many different forms and should not be construed as limited to the embodiments described herein. These embodiments are provided so that the present disclosure is thorough and complete and fully conveys the scope of the subject matter to those skilled in the art. Like numbers refer to like elements throughout.

[0013] As used herein, elements or acts recited in the singular and prefaced with the word "a" or "an" are to be understood as including one or more elements or acts, unless otherwise indicated. Further, various embodiments of the present specification are described in the context of one or more elements or components. An element or component can comprise any structure configured to perform a particular process. Although embodiments may be described, by way of example, in a certain topology with a limited number of elements, an embodiment can include more or fewer elements in an alternative topology as desired for a given embodiment. Note that references to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The phrases "in one embodiment," "in some embodiments," and "in various embodiments" that appear in various places in this specification are not necessarily all referring to the same embodiment.

[0014] Referring now to FIG. 1A, a processing apparatus 100 is shown, which can be used to process a substrate, such as a semiconductor wafer. The processing apparatus 100 includes a process chamber 102. The process chamber 102 includes a substrate holder assembly 106, and the structure and function of the substrate holder assembly 106 will be described below. Briefly, the substrate holder assembly 106 can include a substrate platen 108 disposed to hold a substrate 110, an outer halo 112, and a halo ring 114. The outer halo 112 and the halo ring 114 can be removably fixed to a halo base 115 (described further below) and can function as a substrate assembly 116 for adjusting and improving the processing of the substrate. As shown in FIG. 1A, the process chamber 102 can include a processing nuclide 104 that is used to process a substrate 110 disposed in the substrate assembly 116.

[0015] As further shown in FIG. 1A, the outer halo 112 defines a first aperture, the edge of which is indicated by A1, and the halo ring 114 defines a second aperture, the edge of which is indicated by A2, and the second aperture is concentrically disposed within the first aperture. As shown, the halo ring 114 can be coupled to house the substrate 110 within the second aperture.

[0016] The processing apparatus 100 according to different embodiments can be an etching tool, a deposition tool, or a combination of an etching tool and a deposition tool for performing an etching process on the substrate 110. In some embodiments, the processing apparatus 100 can be an implantation tool for introducing implanted species to the substrate 110. Thus, the processing apparatus 100 can be a plasma-based tool, such as a plasma etching tool like a reactive ion etching tool, a plasma doping (PLAD) apparatus, a plasma enhanced chemical vapor deposition (PECVD) tool, an ion beam tool, a reactive ion beam etching tool, or other tools.

[0017] As schematically shown in FIG. 1A, the processing apparatus 100 can generate and contain processing species 104, which can represent suitable species for performing substrate processing on the substrate 110. Thus, the processing species can include ions, reactive ions, reactive neutrals, implanted species, etc. The processing species 104 are shown as being contained within the process chamber 102, but in various embodiments, the processing apparatus 100 can include a plurality of chambers, separate from the process chamber 102, including an ion source, a plasma source. In other embodiments, the process chamber 102 can be a plasma chamber. The embodiments are not limited to this context.

[0018] Next, referring to FIG. 1B, a front view showing an embodiment of the substrate assembly 116 is shown. In this example, the processing species 104 is configured as an elongated ion beam or ribbon beam, shown in a cross-sectional view within the X-Y plane of the shown orthogonal coordinate system. The ribbon beam can be provided from the plasma chamber through the extraction plate as in known devices. Next, referring to FIG. 1C, a processing apparatus 150 is shown, which includes a plasma chamber 152 adjacent to the process chamber 102 described above. The processing species 104 is extracted as a ribbon beam from the plasma 154 in the plasma chamber 152 as in known devices.

[0019] As shown in FIGS. 1B and 1C, in some embodiments, the substrate holder assembly 106 can be scanned along a direction parallel to the Y-axis of the shown orthogonal coordinate system, as indicated by the arrow. In some embodiments, the ribbon beam containing the processing species 104 can be characterized by a width W, which is greater than the substrate diameter D S In this way, the entire substrate 110 can be processed by the processing species 104.

[0020] According to various embodiments, the outer halo 112 can be formed from a first material, such as any suitable material (e.g., silicon, silicon carbide, doped silicon, quartz, ceramic, etc.). The outer halo 112 can be formed, for example, from a plurality of tiles (further described below). In various embodiments, the halo ring 114 can be formed from a second material, which can be the same as the first material (e.g., silicon, silicon carbide, doped silicon, quartz, ceramic, etc.) or different from the first material.

[0021] In various embodiments, the halo ring 114 can be coupled to the outer halo 112 in a reversibly detachable manner, as described below. The halo ring 114 can thus represent any number of different halo rings, and the material of the halo ring 114 can be selected according to a particular application. Thus, one halo ring 114 can be used in place of another, allowing for replacement due to wear or damage. Further, a first halo ring made from a first halo ring material can be used in place of a second halo ring made from a different second halo ring material when appropriate. For example, when the material of the substrate 110 is changed, or when the processing conditions of the processing apparatus 100 are sufficiently changed, it may be appropriate to exchange the halo ring 114 for another halo ring.

[0022] One function of the substrate assembly 116 according to various embodiments of the present disclosure is to effectively expand the diameter of the substrate 110 in the sense that the halo ring 114 mimics some properties of the substrate 110. As an example, when the substrate 110 is a silicon wafer or a silicon alloy wafer, the halo ring 114 can be composed of a similar material such as silicon, silicon carbide, doped silicon, quartz, or ceramic (e.g., yttria / zirconia blend). In this way, the substrate 110 and the halo ring 114 "appear" to the process species 104 as a substrate having a diameter D H so that the edge effects that would normally be generated near the edge of the substrate 110 by the process species 104 can be reduced or eliminated. Thus, since the width W exceeds the diameter D of the substrate, the edge effect can occur at the outer edge of the ribbon beam defined by the process species 104, or at the outer edge of the halo ring 114. S

[0023] By way of reference, in known halo configurations, the halo can be a monolithic piece formed from a metal such as titanium to provide mechanical and thermal robustness under processing by an ion beam or plasma. Thus, edge effects near the region where the substrate contacts the halo can be generated, at least in part, by the difference in materials between the substrate and the halo.

[0024] According to some non-limiting embodiments, the diameter D H can exceed the width W, and during scanning, the outer edge of the ribbon beam defined by the process species 104 is scanned across the material of the halo ring 114 at its widest part. According to various embodiments, the diameter D H can exceed 300 mm and in some cases can be within the range of 450 mm. The width W of the halo ring 114 R can be on the order of 15 mm to 75 mm. Embodiments are not limited to this context.

[0025] Referring again to FIG. 1A, the halo ring 114 can have an annular first notch or shoulder 120 (hereinafter, “the first shoulder 120”) formed at its radially outermost edge on the front surface thereof, and an annular second notch or shoulder 122 (hereinafter, “the second shoulder 122”) formed at its radially innermost edge on the front surface thereof. The outer halo 112 can have an annular notch or shoulder 124 (hereinafter, “shoulder 124”) formed at its radially innermost edge on the back surface thereof, and the shoulder 124 of the outer halo 112 is disposed in confronting, mating abutment with the first shoulder 120 of the halo ring 114, and the front surface of the halo ring 114 is in the same plane as the front surface of the outer halo 112. The second shoulder 122 of the halo ring 114 can have a depth equal to the thickness 110 of the substrate and can define a counterbore for receiving the substrate 110, and the front surface of the substrate 110 is in the same plane as the front surface of the halo ring 114 as shown.

[0026] In various embodiments, a substrate assembly according to the present disclosure may further include a fastener assembly adapted to reversibly attach an outer halo 112 and a halo ring 114 to a halo base 115 (see FIG. 1A). For example, referring to FIG. 2A, a substrate assembly 200 according to the present disclosure may include an upper halo 112A and a lower halo 112B, and the halo ring 114 is configured concentrically within the upper halo 112A. As shown, the upper halo 112A is formed from a plurality of tiles, and the lower halo 112B is formed from a plurality of tiles. In various alternative embodiments, the upper halo 112A may be formed from a single tile and / or the lower halo 112B may be formed from a single tile. The present disclosure is not limited in this regard. The substrate assembly 200 further includes a fastener assembly configured as a plurality of fasteners 206 that couple the halo ring 114, the upper halo 112A, and the lower halo 112B to the halo base 115.

[0027] Referring to FIG. 2B, a cross-sectional view through section A-A of FIG. 2A extending through one of the fasteners 206 is shown. As shown in FIG. 2B, the fastener 206 may include a stud 214, which may be formed from ceramic or a coated material. The stud 214 is disposed in flat engagement with the front surfaces of the outer halo 112 and the halo ring 114 (and optionally, as shown, disposed within a counterbore formed therein), and may include a head portion 214A and a shank portion 214B extending from the head portion 214A through the outer halo 112 or the halo ring 114 and through the halo base 115. The shank portion 214B may define respective shoulders 214C that face and are spaced from the back side of the halo base 115. The fastener 206 may further include a generally U-shaped retaining clip 216 formed from an elastic material (such as spring steel, plastic, composite material, etc.). The retaining clip 216 may include a first finger 216A and a second finger 216B having respective notches 218A, 218B formed therein. When the retaining clip 216 is operably installed as shown in FIG. 2B, the shank portion 214B of the stud 214 may be disposed within the notches 218A, 218B, and the first finger 216A and the second finger 216B may be compressed between the shoulder 214C of the shank portion 214B and the back surface of the halo base 115 (i.e., compressed toward each other) and held. Thus, the retaining clip 216 applies a rearward force to the shank portion 214B of the stud 214, pulling the head portion 214A of the stud 214 toward the front surface of the halo base 115, and may firmly engage and hold the outer halo 112 and the halo ring 114 thereto.

[0028] In an exemplary embodiment, the maximum holding force generated by fastener 206 can be between 1 lb. and 1.5 lb. This limitation on the clamping force helps ensure that, particularly in embodiments where outer halo 112 and halo ring 114 are made of a brittle material such as silicon, outer halo 112 and halo ring 114 do not break under the stress of the holding force.

[0029] Referring to FIG. 2C, a cross-sectional view showing alternative fastener 306 is presented. In various embodiments of the fastener assembly described above, fastener 306 can be used in place of one or more of fasteners 206. Fastener 306 can include a stud 314 formed from ceramic or a coated material. Stud 314 can include a head portion 314A disposed to engage flatly with the front surfaces of outer halo 112 and halo ring 114 (and optionally, disposed within a counterbore formed therein as shown), and a shank portion 314B extending from head portion 314A through outer halo 112 or halo ring 114 and through halo base 115. Shank portion 314B can have a threaded end 314C disposed proximate the back side of halo base 115. Fastener 306 can further include a coil spring 316 disposed within counterbore 318 on the back side of halo base 115 and surrounding shank portion 314B of stud 314. Fastener 306 can further include a nut 320 that threads onto threaded end 314C of stud 314 and compresses coil spring 316 between nut 320 and back surface 322 of halo base 115 within counterbore 318. Thus, as the nut is tightened onto threaded end 314C, the rearward force applied by coil spring 316 against nut 320 increases, pulling head portion 314A of stud 314 toward the front surface of halo base 115 and firmly engaging and holding outer halo 112 (or halo ring 11).

[0030] In an exemplary embodiment, the maximum holding force generated by the fastener 306 can be from 1 lb. to 1.5 lb. This limitation on the clamping force helps to ensure that, particularly in embodiments where the outer halo 112 and the halo ring 114 are made of a brittle material such as silicon, the outer halo 112 and the halo ring 114 do not break under the stress of the holding force.

[0031] Referring to FIG. 3, an embodiment of a substrate assembly 400 according to the present disclosure is shown, where a halo ring 402 includes an outer ring 406 and an inner ring 404 disposed within the outer ring 406. The inner ring 404 defines a second aperture as described above. The outer ring 406 and the inner ring 404 can be separated from each other or electrically insulated from each other by a gap or spacer shown as spacer 408. In some embodiments, the outer ring 406 comprises a first ring material and the inner ring 404 comprises a second ring material different from the first ring material. According to some embodiments, the inner ring 404 can be electrically biased, or the outer ring 406 can be electrically biased. In some embodiments, the inner ring 404 and the outer ring 406 can be individually coupled to receive different electrical biases as shown by voltage source 410 and voltage source 412, respectively. In some embodiments, the substrate platen 108 can also be coupled to a voltage source 420 and the outer halo 112 is separately coupled to a voltage source 422. Thus, during processing, the voltage applied to the inner ring 404 and the voltage applied to the outer ring 406 can be the same or different from each other. Further, the inner ring 404 and / or the outer ring 406 can be biased at a voltage that is the same as the voltage applied to the substrate platen 108 or different from the voltage applied to the substrate platen 108. Similarly, the outer halo 112 can be coupled to receive a voltage that is the same as or different from the voltage applied to any of the inner ring 404, the outer ring 406, and the substrate platen 108.

[0032] In one embodiment, the inner ring 404, the outer ring 406, or both of them can be configured to be heated separately from the heating applied to the substrate 110, as indicated by heaters 416 and 418, respectively. According to different embodiments, the outer ring 406 and the inner ring 404 can be coupled to receive different temperatures from each other. The substrate platen 108 or the substrate 110 can be coupled to a heater 424 to be heated separately from the inner ring 404 and the outer ring 406, and the outer halo 112 is independently coupled to a heater 426. Thus, these components can be heated to the same temperature or different temperatures from the temperature for other components of the substrate assembly 400.

[0033] A halo ring, such as the halo ring 402, can be flexibly configured to define a plurality of planes, such as a first plane for the inner ring 404 and a second plane for the outer ring 406. Thus, by applying biasing or heating to the halo ring or the inner and outer halo rings independently from the substrate platen or independently from the outer halo, the local environment near the periphery of the substrate can be carefully adjusted or controlled to account for edge effects and to improve process uniformity.

[0034] In a particular embodiment where a silicon halo is employed in an ion beam etching system along with the etching of a silicon wafer, the etching rate variation across the wafer was improved from a 5% non-uniformity when the halo ring was not used to a 1% uniformity when the halo ring was used.

[0035] In summary, the embodiments described herein provide at least the following technical advantages. Regarding the first advantage, the present embodiment provides flexibility to reduce edge effects by providing a detachable halo ring, and the material of the halo ring can be changed to adapt to substrate changes or process changes. Regarding the second advantage, the use of a narrow insert as the halo ring allows the material to be easily replaced to adapt to wear.

[0036] The present disclosure should not be limited by the specific embodiments described herein. In fact, from the above description and the accompanying drawings, various other embodiments and modifications of the present disclosure will become apparent to those skilled in the art in addition to those described herein. Accordingly, such other embodiments and modifications are intended to fall within the scope of the present disclosure. Further, the present disclosure has been described in the context of specific embodiments in a specific environment for a specific purpose. Those skilled in the art will recognize that the usefulness is not limited thereto and that the present disclosure can be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below should be construed in view of the full breadth and spirit of the present disclosure described herein.

Claims

1. An outer halo defining a first aperture, A halo ring disposed at least partially within the first aperture, the halo ring defining a second aperture concentrically disposed within the first aperture, the halo ring being coupled to receive a substrate therein, the halo ring, A fastener assembly disposed to reversibly attach the outer halo and the halo ring to a halo base, A substrate assembly comprising: The fastener assembly includes a stud having a shank portion defining a shoulder, and a U-shaped retaining clip formed of an elastic material and having a first finger and a second finger each having a notch forming a bifurcated edge, the shank portion of the stud extending through the notch, the U-shaped retaining clip being compressed and held between the shoulder and the back surface of the halo base, The outer halo and the halo ring are formed of at least one of silicon, silicon carbide, doped silicon, quartz, and ceramic, Substrate assembly.

2. The substrate assembly according to claim 1, wherein the outer halo and the halo ring are entirely formed of silicon.

3. The substrate assembly according to claim 1, wherein the halo ring includes an outer ring and an inner ring disposed within the outer ring, the inner ring defining the second aperture, the outer ring comprising a first ring material, and the inner ring comprising a second ring material different from the first ring material.

4. An outer halo defining a first aperture, A halo ring disposed at least partially within the first aperture, the halo ring defining a second aperture concentrically disposed within the first aperture, the halo ring being coupled to receive a substrate therein, the halo ring, A fastener assembly disposed to reversibly attach the outer halo and the halo ring to a halo base, A substrate assembly comprising: The fastener assembly includes a stud having a shank portion with a threaded end, a nut that screws onto the threaded end, and a coil spring that surrounds the shank portion and is compressed and held between the nut and the back surface of the halo base. The outer halo and the halo ring are at least partially formed from one of silicon, silicon carbide, doped silicon, quartz, and ceramic, a substrate assembly. **Claim 5** The halo ring has an annular first shoulder formed at the radially outermost edge of the front surface of the halo ring and an annular second shoulder formed at the radially innermost edge of the front surface of the halo ring, and the outer halo has an annular shoulder formed at the radially innermost edge of its back surface, and the annular shoulder of the outer halo is fitted and abutted against the first shoulder, the substrate assembly according to claim 1. **Claim 6** The front surface of the halo ring is on the same plane as the front surface of the outer halo, the substrate assembly according to claim 5. **Claim 7** A substrate platen arranged to support a substrate at a substrate position, A halo ring arranged around the substrate position, An outer halo arranged around the halo ring and defining a first aperture, A fastener assembly arranged to reversibly attach the outer halo and the halo ring to a halo base, A substrate holder assembly comprising, wherein the outer halo is arranged to engage the halo ring, the halo ring is at least partially arranged within the first aperture, the halo ring defines a second aperture concentrically arranged within the first aperture, The fastener assembly includes a stud having a shank portion that defines a shoulder, and a U-shaped retaining clip formed of an elastic material and having a first finger and a second finger each having a notch that forms a bifurcated edge, the shank portion of the stud extending through the notch, and the U-shaped retaining clip being compressed and held between the shoulder and the back surface of the halo base. The outer halo and the halo ring are formed at least in part from one of silicon, silicon carbide, doped silicon, quartz, and ceramic, a substrate holder assembly. **Claim 8**: A substrate platen disposed to support a substrate at a substrate position, a halo ring disposed around the substrate position, an outer halo disposed around the halo ring and defining a first aperture, a fastener assembly disposed to reversibly attach the outer halo and the halo ring to a halo base, A substrate holder assembly comprising: The outer halo is disposed to engage the halo ring, the halo ring is disposed at least in part within the first aperture, the halo ring defines a second aperture concentrically disposed within the first aperture, The fastener assembly includes a stud having a shank portion with a threaded end, a nut that threads onto the threaded end, and a coil spring that surrounds the shank portion and is held compressed between the nut and the back surface of the halo base. The outer halo and the halo ring are formed at least in part from one of silicon, silicon carbide, doped silicon, quartz, and ceramic, a substrate holder assembly. **Claim 9** The substrate holder assembly according to claim 7 or 8, wherein the outer halo and the halo ring are entirely formed of silicon. **Claim 10** The substrate holder assembly according to claim 7 or 8, wherein the halo ring includes an outer ring and an inner ring disposed within the outer ring, the inner ring defines the second aperture, the outer ring comprises a first ring material, and the inner ring comprises a second ring material different from the first ring material. **Claim 11** The substrate holder assembly according to claim 7 or 8, wherein the halo ring has an annular first shoulder formed at a radially outermost edge of a front surface of the halo ring and an annular second shoulder formed at a radially innermost edge of the front surface of the halo ring, the outer halo has an annular shoulder formed at a radially innermost edge of a back surface thereof, and the annular shoulder of the outer halo is disposed in fitting abutment facing the first shoulder.

12. A processing apparatus comprising: a process chamber; and a substrate holder assembly disposed in the process chamber, wherein the substrate holder assembly includes: a substrate platen disposed to support a substrate at a substrate position; a halo ring disposed around the substrate position; an outer halo disposed around the halo ring and configured to engage the halo ring; and a fastener assembly disposed to reversibly attach the outer halo and the halo ring to a halo base, wherein the fastener assembly includes a stud having a shank portion defining a shoulder, and a U-shaped retaining clip formed of an elastic material and having a first finger and a second finger each having a notch forming a bifurcated edge, the shank portion of the stud extending through the notch, and the U-shaped retaining clip being compressed and held between the shoulder and the back surface of the halo base; wherein the outer halo and the halo ring are formed at least in part from one of silicon, silicon carbide, doped silicon, quartz, and ceramic; a processing apparatus.

13. A processing apparatus comprising: a process chamber; and a substrate holder assembly disposed in the process chamber, wherein the substrate holder assembly includes: a substrate platen disposed to support a substrate at a substrate position; a halo ring disposed around the substrate position; an outer halo disposed around the halo ring and configured to engage the halo ring; and a fastener assembly disposed to reversibly attach the outer halo and the halo ring to a halo base, wherein the fastener assembly includes a stud having a threaded end portion, a nut threaded onto the threaded end portion, and a coil spring surrounding the shank portion and compressed and held between the nut and the back surface of the halo base; wherein the outer halo and the halo ring are formed at least in part from one of silicon, silicon carbide, doped silicon, quartz, and ceramic; a processing apparatus.

14. The processing apparatus according to claim 12 or 13, wherein the outer halo and the halo ring are entirely formed of silicon.

15. The processing apparatus according to claim 12 or 13, wherein the halo ring includes an outer ring and an inner ring disposed within the outer ring, and the inner ring is disposed around the substrate position.

16. The processing apparatus according to claim 15, wherein the outer ring includes a first ring material, and the inner ring includes a second ring material different from the first ring material.

17. The processing apparatus according to claim 15, further comprising a first voltage source electrically coupled to the inner ring and a second voltage source electrically coupled to the outer ring independently of the first voltage source.

18. The processing apparatus according to claim 15, further comprising a first heater coupled to the inner ring and a second heater coupled to the outer ring independently of the first heater.

Images