Susceptor for semiconductor substrate processing

Abstract

To provide a semiconductor processing system and method for addressing quality control related to a physical interaction between a substrate and a susceptor.SOLUTION: In a semiconductor processing system, a susceptor 100 comprises an inner susceptor portion 102 and an outer susceptor portion 104. The susceptor portions self-align via complementary features, such as tabs on the outer susceptor and recesses on the inner susceptor portion. The inner susceptor portion contains several contact pads 106 to support a wafer during semiconductor processing. The contact pads are hemispherical to reduce the contact area with the wafer, thereby reducing the risk of backside damage. The inner susceptor portion contains a cavity to receive a thermocouple. The diameter of the cavity is greater than the diameter of the thermocouple such that the thermocouple does not contact walls of the cavity during processing, thereby providing highly accurate temperature measurements.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Cross-Reference to Related Applications All applications in which a foreign or domestic priority claim is identified in the application data sheet filed with this application are hereby incorporated by reference into this specification under 37 CFR 1.57. This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 925,705, filed October 24, 2019, entitled "SUSCEPTOR FOR SEMICONDUCTOR SUBSTRATE PROCESSING", which is hereby incorporated by reference in its entirety.

[0002] The present disclosure generally relates to semiconductor processing, and more specifically to susceptors for supporting semiconductor substrates in a processing chamber.

Background Art

[0003] Semiconductor substrates, such as semiconductor wafers, are typically processed in a processing chamber under controlled processing conditions that include exposure to high temperatures. A base commonly referred to as a "susceptor" is typically used to support the substrate during processing in the processing chamber (e.g., during deposition). To facilitate automated processing, a robotic arm may be used to place the substrate on the susceptor and then remove the substrate from the reactor after processing.

[0004] Several quality control issues related to the physical interaction between the substrate and the susceptor can occur during processing, and there continues to be a need to address these quality control issues.

Summary of the Invention

[0005] Various examples of susceptors for supporting semiconductor substrates, as well as related processing systems and methods, are disclosed.

[0006] In some embodiments, an apparatus is provided for processing a substrate and includes a processing chamber configured to receive the substrate and a susceptor disposed within the processing chamber and configured to support the substrate. The susceptor includes an inner susceptor portion and an outer susceptor portion surrounding the inner susceptor portion. The inner susceptor portion includes a plurality of recesses, and the outer susceptor portion includes a plurality of extensions extending under the inner susceptor portion to support the inner susceptor portion. Each of the extensions generally has a triangular shape and is aligned within a corresponding one of the recesses. The triangular apex of the extension projects toward the center of the inner susceptor portion.

[0007] In some other embodiments, a susceptor for supporting a substrate is provided. The susceptor includes an inner susceptor portion including a plurality of recesses and an outer susceptor portion surrounding the inner susceptor portion. The outer susceptor portion includes a plurality of extensions extending under the inner susceptor portion to support the inner susceptor portion. Each of the extensions generally has a triangular shape and is aligned within a corresponding one of the recesses, and the triangular apex of the extension projects toward the center of the outer susceptor portion.

[0008] In still other embodiments, an apparatus is provided for processing a substrate. The apparatus includes a processing chamber configured to receive the substrate and a susceptor disposed within the processing chamber and configured to support the substrate. The susceptor includes an inner susceptor portion and an outer susceptor portion surrounding the inner susceptor portion. The inner susceptor portion includes a plurality of contact pads extending outwardly from and disposed along the perimeter of the surface of the inner susceptor portion, and the pads are configured to support the substrate and to prevent the substrate from contacting the surface during processing.

[0009] In still other embodiments, a susceptor for supporting a substrate is provided. The susceptor includes an inner susceptor portion that includes a plurality of contact pads that extend outwardly and are disposed adjacent to the periphery of the surface of the inner susceptor portion. The pads are configured to support the substrate and to prevent the substrate from contacting the surface during processing. The susceptor also includes an outer susceptor portion that surrounds the inner susceptor portion.

[0010] In still other embodiments, an apparatus for processing a substrate is provided. The apparatus includes a processing chamber configured to receive the substrate, a susceptor disposed within the processing chamber and configured to support the substrate, and a thermocouple configured to measure the temperature of the susceptor. The susceptor includes an inner susceptor portion and an outer susceptor portion that surrounds the inner susceptor portion. The inner susceptor portion includes a cavity that defines a volume for receiving the thermocouple, the cavity being formed through the lower side of the central portion of the inner susceptor portion. The width of the cavity is greater than the width of the thermocouple, and the thermocouple is separated from the walls of the cavity by a gap.

[0011] In still other embodiments, a method for processing a substrate is provided. The method includes providing a substrate on a susceptor within a processing chamber. The susceptor includes an inner susceptor portion and an outer susceptor portion that surrounds the inner susceptor portion. The inner susceptor portion includes a cavity that defines a volume for receiving the thermocouple, the cavity being formed through the lower side of the central portion of the inner susceptor portion. The method further includes providing a thermocouple within the cavity. The thermocouple is separated from the walls of the cavity by a gap. The method further includes processing the substrate on the susceptor within the processing chamber. Processing the substrate includes heating the substrate and the susceptor, and the gap is maintained during processing of the substrate.

[0012] Further examples of embodiments are listed below.

[0013] Example 1 An apparatus for processing a substrate, comprising A processing chamber configured to accommodate a substrate, and a susceptor disposed in the processing chamber and configured to support the substrate, wherein the susceptor includes an inner susceptor portion and an outer susceptor portion surrounding the inner susceptor portion, the inner susceptor portion includes a plurality of recesses, and the outer susceptor portion includes a plurality of extensions extending under the inner susceptor portion to support the inner susceptor portion, each of the extensions generally has a triangular shape, is aligned within a corresponding one of the recesses, and the triangular apex of the extension protrudes toward the center of the inner susceptor portion, the apparatus.

[0014] Example 2 The apparatus according to Example 1, wherein the inner susceptor portion is smaller than the substrate, and the outer susceptor portion extends beyond the substrate.

[0015] Example 3 The apparatus according to Example 1, wherein the inner susceptor portion has a shape in which a first disk and a second disk overlap concentrically with each other, and the first disk has a diameter smaller than the diameter of the second disk.

[0016] Example 4 The apparatus according to Example 1, wherein the outer susceptor portion includes a plurality of concentric annular upper surfaces, and each of the annular upper surfaces is disposed on a different vertical plane.

[0017] Example 5 The apparatus according to Example 1, wherein each of the extensions has a radial groove on the lower side of the extension.

[0018] Example 6 The apparatus of Example 1, wherein the edge of the extension is chamfered.

[0019] Example 7 The apparatus according to Example 6, wherein the edge of the extension has a chamfer angle in the range of 60 degrees to 80 degrees.

[0020] Example 8 The apparatus according to Example 1, wherein the inner susceptor has a concave shape corresponding to the concave surface of the substrate during processing of the substrate, and the concave shape has a depth in the range of 0.1 mm to 1 mm.

[0021] Example 9 The apparatus according to Example 1, wherein the inner susceptor portion includes a plurality of contact pads along the periphery of the inner susceptor portion, the pads protrude from the surface of the inner susceptor portion to support the substrate and prevent the substrate from contacting the surface.

[0022] Example 10 The apparatus according to Example 9, wherein the contact pads have a hemispherical shape.

[0023] Example 11 The apparatus according to Example 9, wherein the height of the pads is in the range of about 0.15 mm to 1 mm.

[0024] Example 12 A susceptor for supporting a substrate, an inner susceptor portion including a plurality of recesses, and an outer susceptor portion surrounding the inner susceptor portion, wherein the outer susceptor portion includes a plurality of extensions extending under the inner susceptor portion to support the inner susceptor portion, each of the extensions generally has a triangular shape, is aligned within a corresponding one of the recesses, and the triangular apex of the extension protrudes toward the center of the outer susceptor portion.

[0025] Example 13 The apparatus according to Example 12, wherein the inner susceptor portion is smaller than the substrate and the outer susceptor portion extends beyond the substrate.

[0026] Example 14 The apparatus according to Example 12, wherein the inner susceptor portion has a shape in which a first disk and a second disk overlap concentrically with each other, and the first disk has a diameter smaller than the diameter of the second disk.

[0027] Example 15 The apparatus according to Example 12, wherein the outer susceptor portion includes a plurality of concentric annular upper surfaces, each of the annular upper surfaces being disposed in a different vertical plane.

[0028] Example 16 The apparatus according to Example 12, wherein at least one protruding portion has a groove on the lower side, the groove having a generally triangular shape with a vertex facing radially from the center of the outer susceptor portion.

[0029] Example 17 The apparatus of Example 12, wherein the edge of the protruding portion is chamfered.

[0030] Example 18 The apparatus according to Example 17, wherein the edge of the protruding portion has a chamfer angle in the range of 60 degrees to 80 degrees.

[0031] Example 19 The apparatus according to Example 12, wherein the inner susceptor has a concave shape corresponding to the concave surface of the substrate during processing of the substrate, the concave shape having a depth in the range of 0.1 mm to 1 mm.

[0032] Example 20 The apparatus according to Example 12, wherein the inner susceptor portion includes a plurality of contact pads along the periphery of the inner susceptor portion, the pads protruding from the surface of the inner susceptor portion to support the substrate and prevent the substrate from contacting the surface.

[0033] Example 21 An apparatus for processing a substrate, a processing chamber configured to accommodate the substrate, and a susceptor disposed in the processing chamber and configured to support the substrate, wherein the susceptor includes an inner susceptor portion and an outer susceptor portion surrounding the inner susceptor portion, the inner susceptor portion including a plurality of contact pads extending outwardly from and disposed along the periphery of the surface of the inner susceptor portion, the pads supporting the substrate and preventing the substrate from contacting the surface during processing.

[0034] Example 22 The apparatus according to Example 21, wherein the pad is integrally formed with the inner susceptor portion.

[0035] Example 23 The apparatus according to Example 22, wherein the pad has a hemispherical shape.

[0036] Example 24 The apparatus according to Example 22, wherein the height of the pad ranges from about 0.15 mm to 1 mm.

[0037] Example 25 The apparatus according to Example 22, wherein the diameter of the pad ranges from about 0.75 mm to 1.5 mm.

[0038] Example 26 The apparatus according to Example 21, wherein the inner susceptor portion has a concave shape corresponding to the concave surface of the substrate during processing of the substrate, and the concave shape has a depth in the range of 0.1 mm to 1 mm.

[0039] Example 27 The apparatus according to Example 21, wherein the inner susceptor portion includes a plurality of central contact pads located close to the center of the inner susceptor portion.

[0040] Example 28 The apparatus according to Example 27, wherein the central contact pad has a hemispherical shape.

[0041] Example 29 The apparatus according to Example 27, wherein the height of the central contact pad ranges from about 0.05 mm to 1 mm.

[0042] Example 30 A susceptor for supporting a substrate, an inner susceptor portion, wherein the inner susceptor portion comprises a plurality of contact pads extending outwardly from and disposed adjacent to the periphery of the surface of the inner susceptor portion. The inner susceptor portion is configured to support the substrate and to prevent the substrate from contacting the surface during processing, and a susceptor comprising an outer susceptor portion surrounding the inner susceptor portion.

[0043] Example 31 The apparatus according to Example 30, wherein the pad is integrally formed with the inner susceptor portion.

[0044] Example 32 The apparatus according to Example 31, wherein the pad has a hemispherical shape.

[0045] Example 33 The apparatus according to Example 31, wherein the height of the pad ranges from about 0.15 mm to 1 mm.

[0046] Example 34 The apparatus according to Example 31, wherein the diameter of the pad ranges from about 0.75 mm to 1.5 mm.

[0047] Example 35 The apparatus according to Example 31, wherein the inner susceptor portion has a concave shape corresponding to the concave surface of the substrate during processing of the substrate, and the concave shape has a depth in the range of 0.23 mm to 0.47 mm.

[0048] Example 36 The apparatus according to Example 30, wherein the inner susceptor portion includes a plurality of central contact pads located close to the center of the inner susceptor portion.

[0049] Example 37 The apparatus according to Example 36, wherein the central contact pad has a hemispherical shape.

[0050] Example 38 The apparatus according to Example 36, wherein the height of the central contact pad ranges from about 0.05 mm to 1 mm.

[0051] Example 39 An apparatus for processing a substrate, comprising A processing chamber configured to accommodate a substrate, a susceptor disposed in the processing chamber and configured to support the substrate, and a thermocouple configured to measure the temperature of the susceptor, wherein the susceptor includes an inner susceptor portion and an outer susceptor portion surrounding the inner susceptor portion, the inner susceptor portion includes a cavity defining a volume for accommodating the thermocouple, the cavity being formed through a lower side of a central portion of the inner susceptor portion, the width of the cavity is larger than the width of the thermocouple, and the thermocouple is separated from the wall of the cavity by a gap, the apparatus.

[0052] Example 40 The apparatus according to Example 39, wherein a tip of the thermocouple is in contact with an upper end of the cavity.

[0053] Example 41 The apparatus according to Example 39, wherein a thickness of the inner susceptor portion above the thermocouple is about 1 mm or more.

[0054] Example 42 The apparatus according to Example 39, wherein a depth of the cavity is in a range of about 2.3 mm to 7.7 mm.

[0055] Example 43 The apparatus according to Example 39, wherein a wall of the cavity defines a cylinder.

[0056] Example 44 The apparatus according to Example 39, wherein an upper end of the cavity is flat.

[0057] Example 45 The apparatus according to Example 39, wherein a tip of the thermocouple inside the cavity is hemispherical.

[0058] Example 46 A method for processing a substrate, Providing a substrate on a susceptor within a processing chamber, the susceptor comprising an inner susceptor portion and an outer susceptor portion surrounding the inner susceptor portion, the inner susceptor portion including a cavity defining a volume for receiving a thermocouple, the cavity being formed through the lower side of the central portion of the inner susceptor portion, and Providing a thermocouple within the cavity, the thermocouple being separated from the walls of the cavity by a void, and Processing a substrate on the susceptor within the processing chamber, wherein processing the substrate includes heating the substrate and the susceptor, and the void is maintained during processing of the substrate.

[0059] Example 47 The method according to Example 46, wherein the tip of the thermocouple contacts the upper end of the cavity while processing the substrate.

[0060] Example 48 The method according to Example 46, wherein the material forming the thermocouple has a higher coefficient of thermal expansion than the material forming the susceptor.

[0061] Example 49 The method according to Example 46, wherein the thickness of the inner susceptor portion above the thermocouple is about 1 mm or more.

[0062] Example 50 The method according to Example 46, wherein the depth of the cavity is in the range of about 2.3 mm to 7.7 mm.

[0063] Example 51 The method according to Example 46, wherein the walls of the cavity define a cylinder.

[0064] Example 52 The method according to Example 46, wherein the upper end of the cavity is flat.

[0065] Example 53 The method according to Example 46, wherein the tip of the thermocouple is hemispherical. Brief Description of the Drawings

[0066]

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[0067] As described above, several quality control issues can occur during semiconductor processing, and many of these issues can be related to the physical interaction between the substrate and the susceptor. One problem that can occur when processing a substrate supported on a susceptor is backside damage, i.e., damage to the side of the substrate facing the susceptor. In some cases, backside damage can unnecessarily create optical artifacts that interfere with lithography and subsequent pattern formation of features on the substrate.

[0068] Naturally, backside damage can be caused by differences in expansion and / or warping between the substrate and the underlying susceptor. The susceptor is typically made of a material different from the material forming the semiconductor substrate. Different materials can have different coefficients of thermal expansion. Thus, when the substrate and the susceptor are heated, they expand at different rates, which causes abrasion when the different materials come into contact with each other. Since the susceptor is typically formed of a material harder than the substrate, it is typically the substrate that is scratched or damaged by contact with the susceptor.

[0069] Advantageously, some embodiments described herein can provide point contact between the substrate and the susceptor and can provide high-quality processing results with a low level of backside damage. For example, the susceptor may have a plurality of pads that contact the overlapping substrate at discrete points along the perimeter of the substrate. For example, 3 to 12 pads (including 6 to 12 pads) may be provided equidistantly on the upper surface of the susceptor. It is preferred that 6 or more pads are provided, which serves to prevent the substrate from contacting other parts of the susceptor when the substrate warps unevenly during heating. The pads can limit the contact between the susceptor and the substrate, thereby limiting the degree of backside damage. In addition, in some embodiments, a plurality of pads (1 to 6 pads or 3 to 6 pads) may be provided within the central region of the susceptor to further limit the contact between the susceptor and the substrate in that region. In some embodiments, the contact pads within the central region may be substantially opposite to a cavity for accommodating a thermocouple on the lower side of the susceptor.

[0070] Also, as described above, semiconductor processing is preferably performed under tightly controlled conditions. One of these conditions is temperature. It will be understood that the susceptor can affect the temperature uniformity across the substrate. Since many processing results vary as a function of temperature (e.g., the amount of deposited material can vary in response to local temperature variations across the substrate), temperature non-uniformity across the substrate can affect the uniformity of the processing results across the substrate.

[0071] In some embodiments, a multi-component susceptor can be utilized to facilitate automated substrate handling. The susceptor can have an inner portion smaller than the substrate and an outer portion extending beyond the substrate. During processing, both the inner and outer portions can support the substrate. To enable handling of the substrate, the inner portion can be raised above the outer portion, and since the other portion is smaller than the substrate, the peripheral portion of the substrate is exposed, enabling the substrate to be contacted and handled by a robotic arm.

[0072] The outer susceptor portion extends beneath the inner susceptor portion to support the inner susceptor portion and has a plurality of extensions that integrate with the inner susceptor portion. Unfortunately, the additional material of the extensions can cause temperature non-uniformities in the overlapping substrate. Further, many extensions may fit snugly within cavities on the bottom of the inner portion and may require precise alignment between the inner and outer portions to enable the inner portion to be installed. In some embodiments, the extensions have a generally triangular shape defined by a curved side that extends towards a pointed apex facing towards the interior of the susceptor. The generally triangular shape facilitates self-alignment of the extensions within recesses on the bottom of the inner portion, which advantageously provides a low-profile support that does not extend significantly beneath the overlapping substrate. For example, the triangular shape advantageously reduces the amount of material that extends beneath the substrate compared to rectangular extensions. In some embodiments, the extensions connect to or fit snugly within similarly shaped recesses on the bottom of the inner portion, and thus the extensions and recesses can be said to have complementary shapes that are similar to each other and fit snugly together. The recess may have angled sidewalls that provide a relatively large recess opening where the interior of the recess gradually narrows. In some embodiments, the underside of the extensions has dimples or notches to further reduce the amount of these extensions, thereby further reducing the effect that these extensions have on temperature.

[0073] Of course, another cause of deviation from the ideal processing result can be inaccuracies in the setting of the processing temperature due to inaccurate thermocouple readings. In some embodiments, the susceptor may include an opening for accommodating a thermocouple for measuring the surface temperature of the susceptor (e.g., the temperature of the upper surface of the susceptor, which directly faces the overlapping substrate during holding of the substrate on the susceptor). The opening is sized to maintain a gap between the sidewall of the opening and the sidewall of the thermocouple such that a void is maintained during processing and the coefficient of thermal expansion of the thermocouple is higher compared to the susceptor. In some embodiments, only the upper portion of the thermocouple closest to the upper surface of the susceptor contacts the body of the susceptor. In some other embodiments, the void is maintained between the side surface of the thermocouple and the opening and the upper portion of the opening. One of ordinary skill in the art will understand that the void may contain a gas (including an inert gas) and may be under partial vacuum under processing conditions. Preferably, the volume is devoid of solid material that could cause conductive heat transfer between the thermocouple and the susceptor.

[0074] Referring now to the figures, like numerals in the figures refer to like parts throughout. It will be understood that the figures are not necessarily to scale.

[0075] As described herein, to facilitate handling of the substrate, the susceptor can take the form of an assembly that includes a plurality of separable sections (e.g., two sections that can include an inner susceptor portion and an outer susceptor portion). It is understood that the multi-part susceptor disclosed herein can be used in various semiconductor processing systems, and an example thereof is shown in FIG. 8.

[0076] FIG. 8 schematically shows a cross-sectional side view of a semiconductor processing system according to some embodiments. As shown, the processing system can include a susceptor 150 having both an inner susceptor portion 152 and an outer susceptor portion 154. The inner susceptor portion 152 and the outer susceptor portion 154 can fit together snugly during processing and together support a semiconductor substrate 210.

[0077] Figure 8 further shows the processing chamber 50 in detail. From this cross-sectional view, it can be seen that the outer susceptor portion 154 surrounds the inner susceptor portion 152 and can provide vertical support. As further discussed herein, this vertical support may consist of complementary protruding flanges 156, which are also referred to as overhangs. The outer susceptor portion 154 may project radially inwardly along its lower inner margin to provide a support overhang 156, which can fit snugly into a complementary recess in the lower side of the inner susceptor portion 152. When the susceptor unit is in its lowest position, the outer susceptor portion 154 may be placed on a plurality of supports 160. The drive shaft 130 can enter the processing chamber through an opening 132 at the bottom of the chamber, and the walls of the chamber continue with a sleeve 134 that surrounds the drive shaft 130. The upper end of the drive shaft 130 may articulate with a support spider 120 located below the susceptor unit within the processing chamber. The spider 120 may have a plurality of support elements or arms 122 that extend radially outwardly from a central hub 124. The distal ends of the arms 122 may each terminate in support posts or pins 128 that can fit snugly into recessed seats 126 and 127 on the lower surfaces of the inner susceptor portion or the outer susceptor portion (in this figure, the spider is shown engaged with the inner portion 152). The articulation between the spider arm 122 and the recessed seat 126 can provide positive coupling means for effecting the rotational movement of the susceptor 150 and for maintaining the concentricity of the spider and the susceptor during thermal expansion.

[0078] The susceptor 150 may be surrounded by a temperature correction ring 159 supported on pegs 161 that extend upward from a support ring 140 having legs 141 placed on the bottom wall 20 of the chamber. The thermocouple 129 may be inserted through the ring 159 to sense the temperature of the ring and susceptor within that region. The thermocouple 129 may be inserted into the susceptor through a cavity 125 on the bottom surface of the inner susceptor portion 152, near the center of the inner susceptor portion. The thermocouple 129 may be surrounded by a void such that at least the sides of the thermocouple 129 do not contact the susceptor 150, as depicted, for example, in FIGS. 7A and 7B.

[0079] FIG. 8 also illustrates a robotic arm 190 having an end effector 200 disposed on its distal end and carrying a wafer 210. The robotic arm may enter the processing chamber from an access port (located on the left). The end effector 200 may have a fork-shaped end for placing the wafer on the support arm 202 onto a susceptor, leaving an open area between the arms large enough to accommodate the inner susceptor portion 152. As a result, the inner susceptor portion can move vertically between the open arms 202 of the end effector, thereby picking up (loading) an unprocessed wafer and performing the reverse sequence to remove the processed substrate 210. The arm 190 may then be retracted, and during processing, the substrate 210 placed on the inner susceptor portion 152 is heated and gas flows into the processing chamber 50. During processing, even at high processing temperatures, in some embodiments, the cavity 125 is wide enough to avoid contact between the sides of the thermocouple 129 and the susceptor 150, i.e., the void between the sides of the thermocouple 129 and the susceptor 150 is maintained during processing. As further discussed herein, such an arrangement may have the advantage of providing accurate temperature measurements and, as a result, high-quality processing results.

[0080] Referring now to FIG. 9, there is shown an exploded perspective view of a susceptor including an inner susceptor portion 102 and an outer susceptor portion 104 according to some embodiments. FIG. 9 shows how a susceptor having an inner and outer portion can be separated for loading and unloading of a substrate. Of course, the inner susceptor portion 102 has a smaller area than the substrate held thereon. The inner susceptor portion 102 can be lifted from the outer susceptor 104 during loading and unloading of the substrate. For example, the substrate can be loaded onto the inner portion 102 using a robot arm (not shown) that contacts a portion of the substrate extending beyond the inner susceptor portion 102. Thus, the robot arm can lower the substrate onto the inner susceptor portion 102 and then retract. Next, the inner susceptor portion 102 can be lowered onto the outer susceptor portion 104. Raising and lowering the inner susceptor portion 102 can be accomplished, for example, using lift pins that contact the inner susceptor portion 102 and move the inner susceptor portion 102 up and down without moving the outer susceptor portion 104. During removal of the substrate, the inner susceptor portion 102 may be lifted to provide access to the held semiconductor substrate, and a robot arm can extend under the substrate, contact the substrate, and lift the substrate.

[0081] FIG. 1A is a perspective view looking down from above a susceptor 100 including an inner susceptor portion 102 and an outer susceptor portion 104. The inner susceptor portion 102 can be surrounded by the outer susceptor portion 104. The susceptor 100 may correspond to the susceptor 150 of FIG. 8 and the susceptor of FIG. 9, and it will be understood that the inner susceptor portion 102 and the outer susceptor portion 104 can respectively correspond to the inner susceptor portion 152 and the outer susceptor portion 154 (FIG. 8). In some embodiments, the susceptor 100 can be formed by machining graphite into a desired shape and applying a silicon carbide (SiC) coating. The susceptor 100 can be formed in different shapes, but preferably conforms to the shape of the substrate to be supported. For example, in the case of a circular semiconductor substrate such as a semiconductor wafer, the susceptor 100 may be circular, and both the inner susceptor portion 102 and the outer susceptor portion 104 may be circular (e.g., the inner susceptor portion 102 may generally be in the shape of a disk, and the outer susceptor portion 104 may be in the shape of a flat ring surrounding the inner susceptor portion 102).

[0082] The outer susceptor portion 104 may include a ledge 105a, which may include a bezel that slopes towards the outer edge of the outer susceptor portion 104 or slopes upward. The bezel is preferably positioned to extend around the perimeter of the substrate with the holding of the substrate on the susceptor 100. In some embodiments, when the substrate is supported by the inner susceptor portion 102, the ledge 105a can contact the substrate due to the upward slope of the ledge 105a. In some embodiments, the contact between the ledge 105a and the substrate may prevent the substrate from moving, which can help reduce backside damage to the substrate.

[0083] The inner susceptor portion 102 may include a plurality of contact pads or protrusions 106 along the perimeter of the inner susceptor portion 102. The contact pads 106 may be on the upper surface of the inner susceptor portion 102. When the inner susceptor portion 102 holds the substrate, the plurality of contact pads 106 contact the substrate. Advantageously, while providing support for the substrate, the plurality of contact pads 106 as a whole contact only a small surface area of the substrate, which can reduce the instances of backside damage that can occur during wafer processing and handling.

[0084] In some embodiments, the plurality of contact pads 106 are separated at equal distances around the perimeter of the inner susceptor portion 102. In some embodiments, the contact pads 106 are disposed in direct proximity to the edge of the inner susceptor portion 102. The plurality of contact pads 106 are in some embodiments a total of three or more, or 3 - 12 contact pads, or 6 - 12 contact pads. While only three contact pads may be required to define a plane and support the substrate, six contact pads have been found to advantageously address non-uniform substrate warping during heating and processing (such as during epitaxial silicon deposition, etc.). Even with this warping, the six contact pads are thought to provide sufficient contact with the warped portion to prevent contact between the substrate and the main surface of the inner susceptor portion 102.

[0085] Continuing to refer to FIG. 1A, in some embodiments, the plurality of contact pads 106 may be integrally formed with the inner susceptor portion 102, which provides good thermal stability and integrity for the contact pads. For example, the contact pads 106 may be machined to be formed on the inner susceptor portion 102. In some other embodiments, the contact pads 106 may be separately formed and attached to the body of the inner susceptor portion 102. Of course, the contact pads 106 can have various shapes. For example, the contact pads 106 may be hemispherical mounts as shown in FIG. 1B, which can provide a relatively small surface area in contact with the substrate. In some other embodiments, the plurality of contact pads 106 may be cylindrical. The diameter of the contact pads 106 can range from about 0.5 mm to 3 mm, 0.5 mm to 2 mm, 0.75 mm to 1.50 mm (including about 1 mm in some embodiments). The contact pads 106 can have a symmetric cross-sectional shape (e.g., generally circular, or a polygon such as hexagonal, orthogonal, etc.) as seen in a top-down view. The shape of the contact pads 106 can be configured to provide good substrate stability with a small contact area with the overlapping substrate. In some embodiments, the plurality of contact pads 106 may be polished, which provides a more uniform contact surface with the substrate, while the other parts of the inner susceptor portion may not need to be polished. The polishing can provide a roughness of less than 0.4 micron Ra, less than 0.3 micron Ra, or less than 0.2 micron Ra on at least the upper surface of the contact pads 106 that are expected to contact the overlapping substrate. In some other embodiments, the plurality of contact pads 106 may not need to be polished.

[0086] The height of the contact pads is preferably sufficient to allow air to escape between the inner susceptor portion 102 and the substrate at a high enough rate to prevent a gas cushion that would cause undesirable lateral substrate movement during substrate loading when the substrate is lowered over the inner susceptor portion 102. In some embodiments, radial grooves may be provided on the surface of the inner susceptor portion 102 to form ventilation holes that assist in venting gas from the inner susceptor portion 102 during substrate loading. Additionally, the height of the contact pads 106 may be selected to maintain a sufficient gap between the substrate and the inner susceptor portion 102 due to warping of the substrate during processing. In some embodiments, the height of the contact pads may be in the range of about 0.10 mm to 1 mm, about 0.10 mm to 0.5 mm, or about 0.15 mm to 0.2 mm. In some embodiments, the height is about 0.18 mm. In some embodiments, there are no grooves and the upper surface of the inner susceptor portion 102 is flat except for the contact pads 106.

[0087] FIG. 2 shows a perspective view looking down from above the inner susceptor portion 102 having a plurality of additional central contact pads 108. The central contact pads 108 are located within the inner region of the upper surface of the inner susceptor portion 102 facing the substrate, inside the contact pads 106. For example, the central contact pads 108 may be located proximate to the center of the inner susceptor portion 102 and may surround the center point of the inner susceptor portion 102. These central contact pads 108 enable the inner susceptor portion 102 to contact and support the central region of the overlapping substrates, and also prevent contact with the upper main susceptor surface in the event that the substrate deforms during processing (e.g., if the central region of the substrate sags during processing). The plurality of central contact pads 108 may be, in some embodiments, a total of 1 to 6, or 3 to 6 contact pads. In some embodiments, the inner susceptor portion 102 may include a total of 3 central contact pads 108.

[0088] Of course, the composition described above, and / or the shape of the contact pad 106, applies to the central contact pad 108. For example, the central contact pad 108 may be a hemispherical mount integrally formed with the body of the inner susceptor portion 102. In some embodiments, the central contact pad 108 may be cylindrical. The central contact pad 108 may have a symmetric cross-section as viewed in a top-down view. In some embodiments, the height of the central contact pad 108 may be lower than the height of the contact pad 106, which may help to address rupture or deformation of the substrate during processing. For example, the individual height of the central contact pad 100 may be in the range of about 0.05 mm to 1 mm, about 0.05 mm to 0.5 mm, or about 0.05 mm to 0.2 mm in some embodiments. In some embodiments, the height may be about 0.1 mm. In some embodiments, the contact pad 106 and the central contact pad 108 may have similar shapes and heights. In some other embodiments, the contact pad 106 and the central contact pad 18 may have different shapes and / or heights.

[0089] Referring now to FIG. 3, a top-down perspective view of the susceptor 100 including the inner susceptor portion 102 and the outer susceptor portion 104 is shown. Also illustrated is an example of a corresponding depth plot 110 of the inner susceptor portion 102. During heating, it has been observed that the substrate may deform or bend due to various mechanisms including the differential thermal expansion of the substrate. For example, the substrate may bend such that its innermost portion is at the maximum depth, and the substrate has a depth that gradually decreases as the distance to the edge of the substrate decreases, and thus the substrate may form a concave shape. In some embodiments, providing a concave surface on the susceptor 100 that corresponds to the curvature of the wafer may reduce backside damage. To compensate for this deformation that causes the substrate to have a concave surface, the susceptor assembly 100 may also include a substantially matching concave surface.

[0090] Continuing to refer to FIG. 3, depth plot 110 shows an example of the concave surface of susceptor 100. The central region is at the maximum depth, and the various other patterns depict depths that gradually decrease from the inside to the outside, along the periphery, to the shallowest depth. For ease of illustration, while depth plot 110 depicts depths that appear as (section-to-section) rigid depth changes, the depth actually changes gradually.

[0091] In some embodiments, as depicted in depth plot 110, the maximum depth at the center of susceptor 100 can range from about 0.1 mm to 1 mm, from about 0.15 mm to 0.8 mm, or from about 0.23 mm to 0.47 mm. In some embodiments, the depth at the center of the susceptor can be about 0.35 mm.

[0092] In some other embodiments, as depicted in depth plot 110, the maximum depth at the center of susceptor 100 can range from about 0.4 mm to 1 mm. In some embodiments, the depth at the center of the susceptor can be about 0.48 mm. Further, the spherical radius of susceptor 100 can be 19000 mm to 25000 mm, or 21901.28 mm in some embodiments. To achieve the overall susceptor depth described herein, inner susceptor portion 102 can have a depth in the range of about 0.1 mm to 0.4 mm in some embodiments, and outer susceptor portion 104 can have a depth in the range of about 0.4 mm to 1 mm. In some embodiments, the depth at the center of inner susceptor portion 102 can be about 0.38 mm, and the depth at the center of outer susceptor portion 104 can be about 0.48 mm.

[0093] Referring now to FIG. 4A, a perspective view of the outer susceptor portion 104 is shown. In some embodiments, the outer susceptor portion 104 may have a diameter in the range of about 330 mm to 370 mm, about 340 mm to 360 mm, or about 351.53 mm to 352.05 mm. In some embodiments, the diameter of the outer susceptor portion may be about 351.79 mm. The diameter of the outer susceptor portion 104 may depend on the size of the semiconductor being processed. The outer susceptor portion 104 preferably supports the inner susceptor portion 102, and the diameter of the outer susceptor portion 104 may be derived from the wafer diameter. In some embodiments, the outer susceptor portion 104 may have a thickness in the range of about 4 mm to 8 mm, about 5 mm to 7 mm, or about 6.09 mm to 6.61 mm. In some embodiments, the thickness of the outer susceptor portion may be about 6.35 mm. Similar to the diameter, the thickness of the outer susceptor portion 104 may be affected by the thickness of the semiconductor and the inner susceptor portion 102. Since the outer susceptor portion is made of layers of surfaces (including surfaces at different heights as described below), the thickness of each layer may depend on the thickness of the inner susceptor portion 102 supported by the layer. In turn, the thickness of the inner susceptor portion 102 may depend on the thickness of the wafer. In some embodiments, the central hole of the outer susceptor portion 104, defined by the inner edge of the lowest upper surface 104c (as described below), may have a diameter in the range of about 200 mm to 250 mm, about 210 mm to 240 mm, or about 225.34 mm to 225.4 mm. In some embodiments, the inner diameter of the upper surface 104b may be about 225.37 mm. The inner diameter of the outer susceptor portion 104 may also depend on the size of the semiconductor being processed. The inner edge of the outer susceptor portion 104 ring may support the inner susceptor portion 102 and thus may be sized to accommodate the inner susceptor portion 102. The inner susceptor portion 102 may be sized to accommodate the wafer.

[0094] Continuing to refer to FIG. 4A, the outer susceptor portion 104 may have a plurality of upper surfaces 104a, 104b, 104c at different heights, and each upper surface is disposed on a different plane (at different vertical levels) as shown in FIG. 4A. The upper surfaces 104a, 104b, 104c may have a donut shape or a ring shape. The upper surfaces 104a, 104b, 104c may be aligned along a common central axis such that the upper surfaces 104a, 104b, 104c are concentric with each other when viewed from above. The upper surfaces 104a, 104b, 104c may be aligned with the disk of the inner susceptor portion 102 such that the outer susceptor portion and the inner susceptor portion are connected, thereby holding the components in place relative to each other (e.g., as described in connection with FIG. 9). The outer susceptor portion 104 may include ledges 105a, 105b. The ledge 105a connects the upper surfaces 104a, 104b, and the ledge 105b connects the upper surfaces 104b and 104c. The ledges 105a, 105b may be inclined with respect to the upper surfaces 104a, 104b, 104c (e.g., the ledges 105a, 105b may be angled downwardly toward the upper surfaces 104b and 104c, respectively). As described above, the outer susceptor portion 104 supports the inner susceptor portion 102, which in turn supports the substrate during processing. To firmly hold the inner susceptor portion 102 in place, the outer susceptor portion 104 can include a plurality of extensions or tabs 402 that contact and support the inner susceptor portion 102 (FIG. 1A). In some embodiments, the lowest upper surface 104c may have tabs 402. In some other embodiments, the other upper surfaces 104a, 104b may have tabs 402. In some embodiments, the number of tabs 402 may be three tabs. However, the number of tabs can be selected to be easy to manufacture while still firmly holding the inner susceptor portion 102. The outer susceptor portion preferably includes three or more tabs 402. In some embodiments, the tabs 402 may have a length in the range of about 5 mm to about 9 mm, about 6 mm to 8 mm, about 6.87 mm to 7.13 mm. In some embodiments, the length of the tab may be about 7 mm.

[0095] In an embodiment where the tab 402 is located on the same plane as the lowest upper surface 104c, the lowest upper surface 104c can form an inner slot on which the inner susceptor portion can be placed. The distance between the lowest upper surface 104c and the next surface 104b can be the depth of the inner slot. In some embodiments, the inner slot can have a diameter in the range of about 200 mm to 300 mm, about 230 mm to 270 mm, or about 244.16 mm to 244.32 mm. In some embodiments, the diameter of the inner slot may be about 244.24 mm. The inner slot can have a depth in the range of about 2 mm to 3 mm, about 2 mm to 2.5 mm, or about 2.26 mm to 2.36 mm. In some embodiments, the depth of the inner slot may be about 2.31 mm.

[0096] Figure 4B is a side cross-sectional view of an outer susceptor portion according to some embodiments. The ledges 105a, 105b can be inclined upward at an angle in the range of about 2.9 degrees to 3.1 degrees, or about 2.95 degrees to 3.05 degrees, with respect to the horizontal axis of the susceptor (e.g., the horizontal plane on which the susceptor is placed). In some embodiments, the angle may be about 3 degrees. The ledges may be fully polished or polished only at the bevel. In some embodiments, the ledges may have an average roughness profile Ra of about 0.4 micron Ra or less, about 0.3 micron Ra or less, or about 0.2 micron or less.

[0097] FIG. 4C is a perspective view of the underside of the outer susceptor portion according to some embodiments. Referring now to FIG. 4C, a groove 402a is formed below each tab 402. The groove 402a may be formed radially from the apex of a generally triangular shape. The groove 402a may have a V-shaped cross-sectional shape when viewed in cross-section taken along a plane transverse to the radial axis. The groove 402a may reduce the thermal mass of the tab 402, which may reduce the effect of the tab 402 on the temperature across the inner susceptor portion 102, for example, by reducing the amount of heat absorbed by the tab 402. Therefore, when the inner susceptor portion 102 is in contact with the tab 402 during substrate processing, the inner susceptor portion 102 may maintain a more uniform temperature across its surface. Subsequently, a more uniform temperature can be maintained across the entire substrate, which may reduce substrate temperature non-uniformity and related process non-uniformity. Of course, the groove 402a may be shaped and sized to accommodate susceptor support pins or other support structures. It has been found that the shape of the tab 402 may further determine the amount of temperature non-uniformity and the ease of alignment of the inner susceptor portion 102 with the outer susceptor portion 104. Referring now to FIG. 5, a comparison of two exemplary shapes of the tab 402 is illustrated. The first tab shape 504 is generally rectangular, and the second tab shape 502 is generally triangular. In some embodiments, the second tab shape 502 may be generally understood to be triangular in the sense that the main spread of the sides of the shape converges at a common point when extended. In contrast, the main spread of the sides of the generally rectangular first tab shape 504 is parallel and can extend infinitely without converging.

[0098] Continuing to refer to FIG. 5, the second tab shape 502 has a reduced perimeter and a reduced contact area compared to the first tab shape 504. The area of the second tab shape 502 can be less than or equal to half the area of the first tab shape 504. In some embodiments, the area of the second tab shape 502 is approximately 24% of the area of the first tab shape 504. Further, the perimeter of the second tab shape 502 can also be less than or equal to half the area of the first tab shape 504. In some embodiments, the perimeter length of the second tab shape 502 is approximately 43% of the perimeter length of the first tab shape 504. The plurality of tabs are the contact points between the inner susceptor portion 102 and the outer susceptor portion 104, and thus, the tab with the smaller surface area will provide a smaller contact surface area, which can reduce the area and / or temperature non-uniformity across the substrate.

[0099] The substantially triangular tab design of the second tab shape 502 can provide a self-centering effect when aligning the inner susceptor portion 102 with the outer susceptor portion 104, especially when compared to the substantially rectangular shape of the first tab shape 504. In some embodiments, the edges of the first tab shape 504 and the second tab shape 502 may be chamfered to further facilitate self-centering. For example, with the tabs 502 and 504 horizontally oriented, it can be understood that the walls of the edges of the tabs are inclined at an angle such that the lower part of the tab occupies a larger area than the upper part of the tab. In some embodiments, the edge chamfer (the angle formed by the edge of the horizontal plane on which the outer susceptor portion 104 lies flat on top) can be in the range of about 60 degrees to 80 degrees, about 62 degrees to 78 degrees, about 64 degrees to 76 degrees, about 65 degrees to 75 degrees, about 66 degrees to 74 degrees, about 67 degrees to 73 degrees, about 68 degrees to 72 degrees, or about 69 degrees to 71 degrees. In some embodiments, the edge chamfer can be about 70 degrees.

[0100] FIG. 6 shows a perspective view of the underside of the inner susceptor portion 102. In some embodiments, the inner susceptor portion 102 can have a diameter in the range of about 245 mm to 265 mm, about 250 mm to 260 mm, or about 257.46 mm to 257.62 mm, depending on the size of the substrate to be processed on the susceptor 150 of which the inner susceptor portion 102 is a part. In some embodiments, the diameter of the inner susceptor portion 102 may be about 257.54 mm. The inner susceptor portion 102 can have a thickness in the range of about 4.5 mm to 6.5 mm, about 5 mm to 6 mm, or about 5.47 mm to 5.73 mm in some embodiments. In some embodiments, the thickness of the inner susceptor portion 102 may be about 5.6 mm.

[0101] In some embodiments, the inner susceptor portion 102 can have a shape in which a first disk 102a and a second disk 102b having different diameters overlap concentrically with each other when viewed from below. As shown, the second disk 102b can cross completely across and extend beyond the second disk 102a. When the inner susceptor portion 102 and the outer susceptor portion 104 are integrated to form a single unit, the first disk 102a may fit snugly into the opening in the upper surface 104c of the outer susceptor portion, and the second disk 102b may fit snugly into the opening in the upper surface 104b of the outer susceptor. The upper surface 104c of the outer susceptor can support the periphery of the second disk 102b. The first disk 102a can have a diameter in the range of about 200 mm to 250 mm, about 210 mm to 240 mm, about 220 mm to 230 mm, or about 225.12 mm to 225.28 mm in some embodiments. In some embodiments, the diameter of the first disk 102a may be about 225.20 mm. The second disk 102b can have a diameter in the range of about 220 mm to 270 mm, about 230 mm to 260 mm, about 240 mm to 250 mm, or about 244.11 mm to 244.37 mm in some embodiments. In some embodiments, the diameter of the second disk 102b may be about 244.24 mm.

[0102] The first disk 102a may have a recessed sheet 126 around the inner circumference of the disk. The recessed sheet 126 may take the form of a circular indentation and, as described in connection with FIG. 8, may receive the corresponding robotic arm of the support spider 120. The first disk 102a may have one or more, three or more, or six or more recessed sheets 126. In some embodiments, the first disk 102a may have three recessed sheets 126 on which the inner susceptor portion 102 may be placed on the support spider 120. The first disk 102a may also have cavities 125, 604 near the center of the inner susceptor portion 102 to receive the thermocouples 606 (FIGS. 7A and 7B).

[0103] The lower side of the inner susceptor portion 102 includes a recess 404. For example, the disk 102a may have the recess 404. These recesses 404 face and correspond to the tabs 402 of the outer susceptor portion 104 shown in FIG. 4A. The shape, number, and location of the recesses 404 preferably correspond to the shape, number, and location of the tabs 402. When the inner susceptor portion 102 is lowered onto the outer susceptor portion 104, the recesses 404 and the tabs 402 align and engage, and the tabs 402 fit snugly into the recesses 404. By having corresponding recesses 404 and tabs 402, the inner susceptor portion 102 is held in a stationary position relative to the outer susceptor portion 104, which prevents the held substrate from being damaged by the relative movement of the inner susceptor portion 102 and the outer susceptor portion 104 when a substrate is present on the inner susceptor portion 102.

[0104] The edges of the recesses 404 are preferably chamfered. In some embodiments, the edges are chamfered to provide a relatively large recess opening that gradually decreases in size as the height increases.

[0105] Referring now to FIGS. 7A and 7B, a cross-sectional side view of the inner susceptor portion 102 is shown. An enlarged view of the central portion 602 of the inner susceptor portion 102 is provided. The central portion 602 may include a cavity 604 within the inner susceptor portion 102 in which the thermocouple 606 may be received. Of course, the thermocouple 606 measures the temperature of the inner susceptor portion 102. While intimate contact between the thermocouple 606 and the inner susceptor portion 102 is expected to provide the most accurate temperature measurement, it has been found that limiting the contact between the thermocouple 606 and the inner susceptor portion 102 may improve the accuracy of the temperature measurement. Without being limited by theory, it is believed that the thermocouple 606 may act as a heat sink and may inadvertently transfer heat from the inner susceptor portion 102 while measuring the temperature of the inner susceptor portion 102. Positioning the thermocouple 606 so that it does not contact the wall of the central portion 602 of the inner susceptor portion 102 has been found to provide a more accurate temperature measurement by reducing the amount of heat transferred from within the inner susceptor portion 102. In some embodiments, the cavity 604 is larger than the tip of the thermocouple 606. For example, the cavity 604 may be wider than the width of the thermocouple 606. It will be appreciated that the cavity 604 may be similar to the cavity 125 described in connection with FIG. 8.

[0106] In addition, since both the inner susceptor portion 102 and the thermocouple 606 thermally expand during heating, it will be understood that the diameter of the cavity 604 can be adjusted due to thermal expansion such that the sidewall of the inner susceptor portion 102 does not contact the thermocouple 606. The materials typically used for thermocouples and susceptors have different coefficients of thermal expansion, and it has been found that thermocouples typically expand more than susceptors. In some embodiments, the cross-sectional area of the cavity 604 is preferably larger than the corresponding cross-sectional area of the thermocouple 606 such that a gap is maintained between the thermocouples 606 in the cavity 604 at the high temperatures used in semiconductor processing (e.g., at temperatures of 200 - 1300 °C, 200 - 1000 °C, or 250 - 500 °C). In some embodiments, the gap between the thermocouple 606 and the wall of the cavity 604 can be maintained as a gap containing a gas (e.g., an inert gas) which can be under vacuum in some embodiments. In some other embodiments, the gap may be filled with a suitable material having a low thermal conductivity. The thermocouple 606 may be generally cylindrical in shape with a dome-shaped tip on the end inserted into the cavity 604. The cavity 604 may be generally cylindrical with a flat end in the inner susceptor portion 102. As shown in FIG. 7A, in some embodiments, the gap may extend around the sides and the tip of the thermocouple 606 such that the thermocouple 606 does not contact the inner susceptor portion 102 at all. As shown in FIG. 7B, it is more preferred that the upper portion of the thermocouple 606 contacts the inner susceptor portion 102 to provide a measurement of the susceptor temperature near the upper surface of the susceptor which is very close to the held substrate, while providing only a low level of contact and heat conduction between the inner susceptor portion 102 and the thermocouple 606. A portion of the thickness of the inner susceptor portion 102 above the thermocouple 606 is preferably sufficient to protect the thermocouple from direct infrared light (e.g., infrared light from the heating lamps used to heat the processing chamber). In some embodiments, the thickness of the inner susceptor portion 102 above the thermocouple 606 is about 1 mm or more, about 1.2 mm or more, or about 1.3 mm or more, including about 1.3 mm and including an upper limit of 1.5 mm in some embodiments. The total thickness of the inner susceptor portion 102 can be in the range of about 3 mm - 8 mm, about 4 mm - 7 mm, or about 5 mm - 6 mm in some embodiments.The depth of the cavity 604 can be in the range of about 2.3 mm to 7.7 mm, about 4.3 mm to 6.7 mm, or about 4.22 mm to 4.38 mm in some embodiments. In some embodiments, the total thickness of the inner susceptor portion 102 may be about 5.6 mm, the cavity 604 may be about 4.3 mm deep, and the thickness of the inner susceptor portion 102 above the thermocouple 606 is about 1.3 mm.

[0107] It will be appreciated that the position of the upper portion of the thermocouple 606 relative to the inner susceptor portion 102 can affect the accuracy of the temperature reading of the thermocouple. In some embodiments, the thermocouple 606 may be in direct contact with the upper portion of the cavity 604 so as to maintain a low level of heat conduction between the thermocouple 606 and the susceptor, thereby reducing the temperature non-uniformity across the substrate that can be caused by the thermocouple 606 while allowing the thermocouple 606 to measure the temperature of the susceptor at a specific contact point. In some other embodiments, the thermocouple 606 may be surrounded by a void such that the thermocouple is not in contact with the susceptor at all. In such embodiments, the thermocouple 606 can be positioned within a certain distance from the susceptor so that the thermocouple 606 can still obtain the accurate temperature at the center of the susceptor. In embodiments having a void that completely surrounds, the ratio of the void between the thermocouple 606 and the upper portion of the cavity 604 to the void between the side surface of the thermocouple and the wall of the cavity can be about 1:1 or less, about 1:2 or less, about 1:4 or less, or about 1:8 or less. Further, of course, the size of the cavity 604 is small enough to maintain an accurate heat reading while still being able to prevent direct contact between the thermocouple 606 and at least the side portion of the cavity 604. In some embodiments, the diameter of the cavity can be in the range of 3 mm to 8 mm including 4 mm to 5 mm. In some embodiments, the diameter of the cavity may be 4.32 mm.

[0108] In some embodiments, the surface of the outer susceptor portion 104 may include a grid, which may be formed by plateaus or islands of susceptor material separated by grooves. In some other embodiments, the surface of the outer susceptor portion 104 may be smooth and the grid may be omitted. The surface of the outer susceptor portion 104 is preferably smooth to reduce the risk of substrate damage due to contact with sharp grid groove edges.

[0109] Although the invention has been described with respect to specific embodiments, other embodiments will be apparent to those skilled in the art, including embodiments that do not provide all of the features and advantages described herein. Each of the individual variations described and illustrated herein can be readily separated from or combined with features of any of the other several embodiments without departing from the scope or spirit of the disclosure. Those skilled in the art will understand that each has discrete components and features that can be readily separated from or combined with features of any of the other several embodiments without departing from the scope or spirit of the disclosure. For example, in some embodiments, the susceptor can have all of the various features disclosed herein, including the ledges, pads, concave surfaces, extensions, and thermocouple arrangements described above. In some embodiments, the susceptor can include only one or less than all of the above-described features (e.g., only one or less than all of the ledges, pads, concave surfaces, extensions, and thermocouple arrangements described above). All such modifications are intended to be within the scope of the claims related to this disclosure.

Claims

1. An apparatus for processing a substrate, comprising: a processing chamber configured to accommodate the substrate; and a susceptor disposed within the processing chamber and configured to support the substrate, wherein the susceptor includes an inner susceptor portion and an outer susceptor portion surrounding the inner susceptor portion, the inner susceptor portion includes a plurality of recesses, and the outer susceptor portion includes a plurality of extensions extending under the inner susceptor portion to support the inner susceptor portion, each of the extensions generally has a triangular shape and is defined by an inclined side surface extending toward a rounded vertex directed toward the interior of the susceptor, aligns within a corresponding one of the recesses, and the triangular vertex of the extension projects toward the center of the inner susceptor portion.

2. The apparatus according to claim 1, wherein the inner susceptor portion is smaller than the substrate, and the outer susceptor portion extends beyond the substrate.

3. The apparatus according to claim 1, wherein the inner susceptor portion has a shape in which a first disk and a second disk overlap concentrically with each other, and the first disk has a diameter smaller than the diameter of the second disk.

4. The apparatus according to claim 1, wherein the outer susceptor portion includes a plurality of concentric annular upper surfaces, and each of the annular upper surfaces is disposed on a different vertical plane.

5. The apparatus according to claim 1, wherein each extension has a radial groove on the lower side of the extension.

6. The apparatus according to claim 1, wherein the edge of the extension is chamfered.

7. The apparatus according to claim 6, wherein the edge of the extension has a chamfer angle in the range of 60 degrees to 80 degrees.

8. The apparatus according to claim 1, wherein the inner susceptor has a concave shape corresponding to the concave surface of the substrate during processing of the substrate, and the concave shape has a depth in the range of 0.15 mm to 0.8 mm.

9. The apparatus according to claim 1, wherein the inner susceptor portion includes a plurality of contact pads along the periphery of the inner susceptor portion, the pads project from the surface of the inner susceptor portion to support the substrate, and prevent the substrate from contacting the surface.

10. The apparatus according to claim 9, wherein the contact pads have a hemispherical shape.

11. The apparatus according to claim 9, wherein the height of the pad is in the range of 0.10 mm to 0.5 mm.

12. A susceptor for supporting a substrate, an inner susceptor portion including a plurality of recesses, and an outer susceptor portion surrounding the inner susceptor portion, wherein the outer susceptor portion includes a plurality of extensions extending under the inner susceptor portion to support the inner susceptor portion, each of the extensions generally having a triangular shape and being defined by an inclined side extending toward a rounded vertex directed toward the inside of the susceptor, aligning within a corresponding one of the recesses, and the triangular vertex of the extension protruding toward the center of the outer susceptor portion.

13. The susceptor according to claim 12, wherein the inner susceptor portion is smaller than the substrate, and the outer susceptor portion extends beyond the substrate.

14. The susceptor according to claim 12, wherein the inner susceptor portion has a shape in which a first disk and a second disk overlap concentrically with each other, and the first disk has a diameter smaller than the diameter of the second disk.

15. The susceptor according to claim 12, wherein the outer susceptor portion includes a plurality of concentric annular upper surfaces, and each of the annular upper surfaces is disposed in a different vertical plane.

16. The susceptor according to claim 12, wherein at least one of the extensions has a groove on the lower side, and the groove has a generally triangular shape having a vertex facing radially from the center of the outer susceptor portion.

17. The susceptor according to claim 12, wherein an edge of the extension is chamfered.

18. The susceptor according to claim 17, wherein the edge of the extension has a chamfer angle in the range of 60 degrees to 80 degrees.

19. The susceptor according to claim 12, wherein the inner susceptor has a concave shape corresponding to the concave surface of the substrate during processing of the substrate, and the concave shape has a depth in the range of 0.15 mm to 0.8 mm.

20. The susceptor according to claim 12, wherein the inner susceptor portion includes a plurality of contact pads along the periphery of the inner susceptor portion, the pads protruding from the surface of the inner susceptor portion to support the substrate and prevent the substrate from contacting the surface.

21. An apparatus for processing a substrate, a processing chamber configured to accommodate the substrate, and a susceptor disposed in the processing chamber and configured to support the substrate. The susceptor includes an inner susceptor portion and an outer susceptor portion surrounding the inner susceptor portion. The inner susceptor portion includes a plurality of contact pads disposed along the periphery of the surface of the inner susceptor portion, and the pads are configured to support a substrate and to prevent the substrate from contacting the surface during processing. The inner susceptor portion includes a plurality of recesses, and the outer susceptor portion includes a plurality of extensions extending under the inner susceptor portion to support the inner susceptor portion. Each of the extensions generally has a triangular shape and is defined by an inclined side surface extending toward a rounded apex directed toward the interior of the susceptor, aligns within a corresponding one of the recesses, and the triangular apex of the extension projects toward the center of the inner susceptor portion.

22. The apparatus according to claim 21, wherein the pads are integrally formed with the inner susceptor portion.

23. The apparatus according to claim 22, wherein the pads have a hemispherical shape.

24. The apparatus according to claim 22, wherein the height of the pads ranges from 0.10 mm to 0.5 mm.

25. The apparatus according to claim 22, wherein the diameter of the pads ranges from 0.75 to 1.5 mm.

26. The apparatus according to claim 21, wherein the inner susceptor portion has a concave shape corresponding to the concave surface of the substrate during processing of the substrate, and the concave shape has a depth in the range of 0.15 mm to 0.8 mm.

27. The apparatus according to claim 21, wherein the inner susceptor portion includes a plurality of central contact pads located proximate to the center of the inner susceptor portion.

28. The apparatus according to claim 27, wherein the central contact pads have a hemispherical shape.

29. The apparatus according to claim 27, wherein the height of the central contact pads ranges from 0.15 mm to 0.5 mm.

30. A susceptor for supporting a substrate, comprising: An inner susceptor portion, wherein the inner susceptor portion Comprises a plurality of contact pads disposed proximate to the periphery of the surface of the inner susceptor portion. The inner susceptor portion, wherein the pads are configured to support the substrate and to prevent the substrate from contacting the surface during processing. And an outer susceptor portion surrounding the inner susceptor portion. The inner susceptor portion includes a plurality of recesses, and the outer susceptor portion includes a plurality of extensions that extend under the inner susceptor portion to support the inner susceptor portion. Each of the extensions generally has a triangular shape and is defined by an inclined side surface that extends toward a rounded vertex directed toward the inside of the susceptor, aligns within a corresponding one of the recesses, and the triangular vertex of the extension protrudes toward the center of the inner susceptor portion. A susceptor.

31. The susceptor according to claim 30, wherein the pad is integrally formed with the inner susceptor portion.

32. The susceptor according to claim 31, wherein the pad has a hemispherical shape.

33. The susceptor according to claim 31, wherein the height of the pad ranges from 0.15 mm to 0.5 mm.

34. The susceptor according to claim 31, wherein the diameter of the pad ranges from 0.75 mm to 1.5 mm.

35. The susceptor according to claim 31, wherein the inner susceptor portion has a concave shape corresponding to the concave surface of the substrate during processing of the substrate, and the concave shape has a depth in the range of 0.23 mm to 0.47 mm.

36. The susceptor according to claim 30, wherein the inner susceptor portion includes a plurality of central contact pads located close to the center of the inner susceptor portion.

37. The susceptor according to claim 36, wherein the central contact pad has a hemispherical shape.

38. The susceptor according to claim 36, wherein the height of the central contact pad ranges from 0.15 mm to 0.5 mm.

39. An apparatus for processing a substrate, comprising: A processing chamber configured to accommodate the substrate; A susceptor disposed in the processing chamber and configured to support the substrate; A thermocouple configured to measure the temperature of the susceptor, The susceptor includes an inner susceptor portion and an outer susceptor portion surrounding the inner susceptor portion. The inner susceptor portion includes a cavity that defines a volume for accommodating the thermocouple, and the cavity is formed through the lower side of the central portion of the inner susceptor portion. The width of the cavity is larger than the width of the thermocouple, and the thermocouple is separated from the wall of the cavity by a gap. The inner susceptor portion includes a plurality of recesses, and the outer susceptor portion includes a plurality of extensions that extend under the inner susceptor portion to support the inner susceptor portion. Each of the extensions generally has a triangular shape and is defined by an inclined side surface that extends toward a rounded vertex directed toward the interior of the susceptor, aligns within a corresponding one of the recesses, and the triangular vertex of the extension projects toward the center of the inner susceptor portion.

40. The apparatus according to claim 39, wherein the tip of the thermocouple is in contact with the upper end of the cavity.

41. The apparatus according to claim 39, wherein the thickness of the inner susceptor portion above the thermocouple is 1 mm or more.

42. The apparatus according to claim 41, wherein the thickness is less than 1.5 mm.

43. The apparatus according to claim 39, wherein the wall of the cavity defines a cylinder.

44. The apparatus according to claim 39, wherein the upper end of the cavity is flat.

45. The apparatus according to claim 39, wherein the tip of the thermocouple inside the cavity is hemispherical.

46. A method for processing a substrate, comprising: providing the substrate on a susceptor in a processing chamber, wherein the susceptor includes an inner susceptor portion and an outer susceptor portion surrounding the inner susceptor portion, the inner susceptor portion includes a plurality of recesses, the outer susceptor portion includes a plurality of extensions that extend under the inner susceptor portion to support the inner susceptor portion, each of the extensions generally has a triangular shape and is defined by an inclined side surface that extends toward a rounded vertex directed toward the interior of the susceptor, aligns within a corresponding one of the recesses, the triangular vertex of the extension projects toward the center of the inner susceptor portion, the inner susceptor portion includes a cavity that defines a volume for accommodating a thermocouple, and the cavity is formed through the lower side of the central portion of the inner susceptor portion; providing a thermocouple in the cavity, wherein the thermocouple is separated from the wall of the cavity by a gap; processing the substrate on the susceptor in the processing chamber, wherein processing the substrate includes heating the substrate and the susceptor, and the gap is maintained during processing of the substrate.

47. The method according to claim 46, wherein during the treatment of the substrate, the tip of the thermocouple contacts the upper end of the cavity. **Claim 48** The method according to claim 46, wherein the material forming the thermocouple has a higher coefficient of thermal expansion than the material forming the susceptor. **Claim 49** The method according to claim 46, wherein the thickness of the inner susceptor portion above the thermocouple is 1 mm or more. **Claim 50** The method according to claim 49, wherein the thickness is less than 1.5 mm. **Claim 51** The method according to claim 46, wherein the wall of the cavity defines a cylinder. **Claim 52** The method according to claim 46, wherein the upper end of the cavity is flat. **Claim 53** The method according to claim 46, wherein the tip of the thermocouple is hemispherical.

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