Pedestal and epitaxial layer growth apparatus including same

Abstract

A susceptor is disclosed, the susceptor including: a susceptor including a body, the body including a bottom surface configured to support a wafer and a sidewall configured to extend upwardly from a periphery of the bottom surface; and a temperature control member disposed inside the side wall adjacent to the side wall at an edge of the bottom surface.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2024-0023762, filed on February 19, 2024, which is hereby incorporated by reference as if fully set forth herein. Background of the Invention Technical Field

[0002] The present disclosure relates to a susceptor and an epitaxial layer growth apparatus including the susceptor, and more particularly, to a susceptor and an epitaxial layer growth apparatus including the susceptor, which control heat supplied to an edge of a wafer so that an epitaxial layer grows with a uniform thickness over the entire area of the wafer. Related technical discussions

[0003] An epitaxial wafer is a wafer obtained by growing a thin single crystal layer on a polished wafer serving as a substrate by chemical vapor deposition (CVD) in a chamber heated to a high temperature of 1100° C. or higher.

[0004] Since epitaxial wafers are manufactured by growing an epitaxial layer on a silicon wafer, an epitaxial layer and an epitaxial wafer having a desired resistivity can be manufactured by controlling the doping amount of impurities in the epitaxial layer.

[0005] Epitaxial wafers have high aggregation capability at high temperatures, low latch-up characteristics, and slip resistance, and therefore, they are recently widely used as wafers not only for manufacturing MOS devices but also for manufacturing LSI devices.

[0006] As quality items required for these epitaxial wafers, items for the surface of the epitaxial wafer including the substrate and the epitaxial layer include flatness and particle contamination, and items for the epitaxial layer itself include thickness uniformity, resistivity and resistivity uniformity of the epitaxial layer, metal contamination, stacking errors, and slip dislocations.

[0007] During the process of manufacturing semiconductor devices on epitaxial wafers, the thickness uniformity or flatness of the epitaxial layer has a significant impact on the photolithography process, chemical mechanical polishing (CMP) process, and the bonding process of silicon-on-insulator (SOI) wafers. In particular, edge roll-off (ERO), in which the edge of the wafer is rolled up or down, has a significant impact on defocusing in the photolithography process, polishing uniformity in the CMP process, and bonding failure in the SOI bonding process. As the diameter of the wafer increases to 300 mm or more, the flatness of the wafer edge becomes increasingly important as a quality item for epitaxial wafers. Therefore, it is necessary to find the cause of the phenomenon in which the flatness of the epitaxial wafer edge is distorted. Summary of the Invention

[0008] Accordingly, the present disclosure is directed to a susceptor and an epitaxial layer growth apparatus including the same that substantially obviate one or more problems due to limitations and disadvantages of the related art.

[0009] An object of the present disclosure is to improve the flatness of an epitaxial wafer by growing an epitaxial layer with uniform thickness on the wafer.

[0010] Additional advantages, purposes, and features of the present disclosure will be set forth in part in the following description and will become apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present disclosure. The objectives and other advantages of the present disclosure may be realized and achieved by the structures particularly pointed out in the written description and claims as well as in the accompanying drawings.

[0011] To achieve these objects and other advantages, and in accordance with the purposes of the present disclosure, as embodied and broadly described herein, a susceptor includes a body including a bottom surface configured to support a wafer and a sidewall configured to extend upwardly from a periphery of the bottom surface, and a temperature control member disposed within the sidewall adjacent to the sidewall at an edge of the bottom surface.

[0012] The temperature control member may be formed of the same material as the main body.

[0013] The temperature control member may be provided integrally with the main body.

[0014] The width of the temperature control member may be variable in the horizontal direction.

[0015] The temperature control member may have a plurality of first points having a maximum width in a horizontal direction and a plurality of second points having a minimum width in the horizontal direction, and the first points and the second points may be alternately arranged around a center of the susceptor in a rotational direction thereof.

[0016] The number of the first points and the number of the second points may be four, the first points may be arranged symmetrically with respect to the center of the base, and the second points may be arranged symmetrically with respect to the center of the base.

[0017] The temperature control member may include a first portion having an annular shape and supported by a bottom surface of the body, and a second portion configured to extend from an upper portion of the first portion toward a sidewall of the body.

[0018] A height of a bottom surface of the body in a region where the first portion is provided may be lower than a height of a bottom surface of the body in a region where the wafer is provided.

[0019] A height of an upper surface of the second portion of the temperature control member may be equal to or higher than a height of an upper surface of the wafer.

[0020] A height of an upper surface of the second portion of the temperature control member may be lower than a height of an upper surface of the wafer.

[0021] The temperature control member may have an annular shape having an inverted triangular cross section in a direction from the center of the base toward the outside, and a vertex of the inverted triangular cross section may be disposed in a direction toward the center of the base.

[0022] The height of the base of the inverted triangular cross section may be equal to or higher than the height of the wafer.

[0023] The height of the base of the inverted triangular cross section may be lower than the height of the wafer.

[0024] The wafer may be a silicon wafer, and the first point may be oriented toward the crystal of the silicon. <100> region of the wafer, while the second point can be oriented toward the crystal of silicon <110> chip area.

[0025] In another aspect of the present disclosure, an epitaxial layer growth device includes: a chamber; a susceptor configured to provide an area in which a wafer is placed in the chamber; pins provided below the susceptor to support the wafer; and a reaction gas supply unit that supplies gas to an upper surface of the wafer to grow an epitaxial layer on the surface of the wafer, wherein the susceptor includes a main body including a bottom surface configured to support the wafer and a side wall configured to extend upward from a periphery of the bottom surface; and a temperature control member provided inside the side wall, adjacent to the side wall at an edge of the bottom surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are included here to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this application, illustrate one or more embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. In the drawings:

[0027] Figure 1 An epitaxial layer growth apparatus according to one embodiment of the present disclosure is shown;

[0028] Figure 2 The crystal orientation of the silicon wafer is shown;

[0029] Figure 3 is Figure 2 The thickness profile of the epitaxial layer grown in each direction of the silicon wafer;

[0030] 4A and 4B show Figure 1 Comparative example of base;

[0031] 5A to 5C show Figure 1 An embodiment of a base; and

[0032] Figure 6 5A to 5C are plan views of the base. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings in order to specifically describe the present disclosure and to facilitate understanding of the present disclosure.

[0034] However, the embodiments of the present disclosure may be modified and implemented in various forms, and it is understood that the scope of the present disclosure should not be interpreted as limited to the embodiments described herein. The embodiments of the present disclosure are provided to make the description of the present disclosure more thorough and to fully convey the scope of the present disclosure to those skilled in the art.

[0035] Furthermore, when relative terms such as "first," "second," "below," "lower," "above," and "upper" are used herein, they do not necessarily require or imply any physical or logical relationship between the substances or elements represented by the terms, nor do they necessarily require or imply their order or sequence, and may be used solely to distinguish one substance or element from another.

[0036] Figure 1 An epitaxial layer growth apparatus according to one embodiment of the present disclosure is shown.

[0037] refer to Figure 1 The epitaxial layer growth apparatus 1000 according to this embodiment may include a chamber 200 having an inner space, support pins 220 rotatable within the chamber 200 , and a susceptor 100 disposed on the support pins 220 .

[0038] A wafer may be placed on the susceptor 100 to form an epitaxial layer on the wafer. The wafer may include, for example, a silicon wafer, a silicon carbide wafer, or the like. The wafer may be oriented with a flat surface and may have its upper and lower surfaces mirror-polished.

[0039] A wafer may be placed on the susceptor 100 to form an epitaxial layer on the wafer. The wafer may include any one of wafers having various compositions, for example, a silicon (Si) wafer, a silicon carbide (SiC) wafer, a sapphire (Si2O3) wafer, or a gallium nitride (GaN) wafer, and the wafer is applied to the embodiments and related drawings described below. The wafer may undergo a flat surface orientation, and the upper and lower surfaces of the wafer may be mirror-polished.

[0040] Epitaxial layer growth apparatus 1000 according to this embodiment may include upper dome 500 and lower dome 550. Upper dome 500 and lower dome 550 may include a light-transmitting material, such as high-purity quartz, that transmits light to radiatively heat a wafer.

[0041] The epitaxial layer growth apparatus 1000 according to this embodiment may include a heating member, which may include a first heating member 410 located at the bottom and a second heating member 420 located at the top.

[0042] The first heating member 410 and the second heating member 420 may radiantly heat the susceptor 100 and a wafer placed on the susceptor 100 .

[0043] In addition, the epitaxial layer growth apparatus 1000 according to the present embodiment may include a reaction gas supply unit 600 and a reaction gas exhaust unit 650. For example, the reaction gas supply unit 600 and the reaction gas exhaust unit 650 may be installed on both sides of the susceptor 100. The reaction gas supply unit 600 and the reaction gas exhaust unit 650 may be installed facing each other with the susceptor 100 interposed therebetween. Hydrogen gas injected from the reaction gas supply unit 600, a carrier gas for epitaxial growth, etc. may pass through the susceptor 100 and be exhausted by the reaction gas exhaust unit 650.

[0044] In addition, the epitaxial layer growth apparatus 1000 may include a rotation shaft 70. The rotation shaft 70 may be connected to the susceptor 100 through the support pins 220. The susceptor 100 may also be rotated by the rotation of the rotation shaft 70.

[0045] In epitaxial layer growth apparatus 1000 according to the present embodiment, susceptor 100 includes a main body and a temperature control member, which will be described later.

[0046] Figure 2 shows the crystal orientation of the silicon wafer, and Figure 3 is Figure 2 Thickness profile of the epitaxial layer grown in each direction of the silicon wafer.

[0047] Figure 2 The silicon wafer (Si wafer) may have a diameter of 300 mm, but is not limited thereto. Crystal orientation of the silicon wafer <110> Appears at 12 o'clock, 3 o'clock, 6 o'clock and 9 o'clock directions, and the crystal is oriented <100> Appears in the crystal orientation <110> The position is 45°.

[0048] When using conventional epitaxial layer growth equipment to grow epitaxial layers on silicon wafers by deposition methods, it can be seen that the crystal orientation <110> The epitaxial layer grows faster than in the crystal orientation <100> The thickness of the epitaxial layer on Figure 3 shown.

[0049] This deviation in epitaxial layer thickness is expected to be caused by the temperature distribution on the susceptor on which the silicon wafer is placed, and the growth rate of the epitaxial layer is generally proportional to the growth temperature. Therefore, the more heat supplied to the susceptor, the higher the temperature of the silicon wafer, and therefore the thicker the epitaxial layer will be.

[0050] exist Figure 1 In the epitaxial layer growth apparatus 1000 , it is necessary to control the heat from the first heating member 410 and the second heating member 420 , which is supplied to the silicon wafer through the susceptor 100 or directly supplied to the silicon wafer, or to control the heat discharged to the outside.

[0051] Heat can be transferred from the susceptor 100 or a large area of the silicon wafer to the front surface of the silicon wafer by conduction, and the heat capacity of conduction can be obtained by the following mathematical expression 1.

[0052] <Mathematical expression 1>

[0053] Q=-kA(ΔT / Δx)

[0054] Here, Q is the heat capacity of conduction, k (W / m·K) is the thermal conductivity, A is the contact cross-sectional area of the substrate, and (ΔT / Δx) is the temperature gradient, ie, the temperature change depending on the distance change.

[0055] In addition to this change in the heat capacity that is conducted, it is also necessary to control the heat capacity that is discharged to the outside.

[0056] Therefore, the silicon wafer has a crystal orientation <110> The high growth rate of the epitaxial layer can therefore occur as Figure 3 The thickness deviation of the epitaxial layer shown is small, and therefore, a temperature control member to be described below can be set in the susceptor 100 to control the distribution of heat supplied to the susceptor 100, thereby controlling the temperature distribution of the silicon wafer, thereby making it possible to uniformly control the thickness distribution of the grown epitaxial layer.

[0057] 4A and 4B show Figure 1 Comparison example of base.

[0058] As shown in FIG4A , holes are formed in the susceptor 100 so that the support pins can support the wafer, and as shown in FIG4B , the susceptor 100 may include a bottom surface supporting the wafer and a sidewall surrounding the bottom surface. Here, the wafer may be a silicon wafer or a silicon carbide wafer.

[0059] 5A to 5C show Figure 1 An embodiment of the base, Figure 6 5A to 5C are plan views of the base. Figure 6 Embodiments of a base according to the present disclosure are described.

[0060] like Figure 6 As shown, the temperature control member may be provided in an annular shape surrounding an area where the wafer is provided, and thus the temperature control member may be referred to as a temperature control ring.

[0061] The temperature control member may be formed of the same material as the body of the susceptor 100, and although the body and the temperature control member are shown separately in Figures 5A to 5C, the body and the temperature control member may be provided as one unit. The temperature control member may be formed of a carbon-based material such as silicon carbide (SiC) or graphite.

[0062] The base 100 according to the embodiment shown in Figure 5A may include a main body, which includes a bottom surface 110 supporting a chip and a side wall 120 extending upward from the periphery of the bottom surface 110, and the base 100 includes a temperature control member 150, which is arranged inside the side wall 120 and is adjacent to the side wall 120 at the edge of the bottom surface 110.

[0063] The temperature control member 150 has an inverted triangular cross-section in a direction from the center of the base 100 toward the outside, and more specifically, the inverted triangular cross-section has the shape of a right triangle, which is placed inverted and the vertex of the inverted triangular cross-section is set in a direction toward the center of the base 100, rather than in a direction toward the edge of the base 100.

[0064] Furthermore, in the inverted triangular cross-section of the temperature control member 150, the base of the inverted triangular cross-section is located at the top, and the height ht of the base may be equal to or higher than the height hw of the upper surface of the wafer. This height distribution allows the temperature control member 150 to prevent heat from the wafer, particularly heat near the edge of the wafer, from being discharged outward.

[0065] In FIG5A , if the height ht of the base of the temperature control member 150 is set to be equal to or higher than the height hw of the upper surface of the wafer, the temperature control member 150 becomes thicker and the heat capacity can be increased, and on the other hand, if the height ht of the base of the temperature control member 150 is set to be lower than the height hw of the upper surface of the wafer, the temperature control member 150 becomes thinner and the heat capacity can be reduced, and thus, the temperature can be controlled according to the crystal orientation of the wafer, and thus the thickness of the epitaxial layer to be grown can be controlled. That is, in a case having a crystal orientation <110> The heat capacity can be reduced in the region with crystal orientation <100> The heat capacity can be increased in the region of the substrate, thereby enabling the thickness of the epitaxial layer to be grown to be controlled.

[0066] 5B, the base 100 may be the same as the base 100 in the embodiment shown in FIG5A, but may have a temperature control member 152 arranged in a different shape. The temperature control member 152 may be arranged inside the side wall 120, adjacent to the side wall 120 at the edge of the bottom surface 110.

[0067] In addition, the temperature control member 152 may have an overall annular shape, but in a direction from the center of the base 100 toward the outside, the cross-section of the temperature control member 152 may include a first portion 152a supported by the bottom surface 110 of the main body, and a second portion 152b extending from the upper portion of the first portion 152a toward the side wall 120 of the main body, and therefore, the temperature control member may have a roughly inverted L shape.

[0068] Here, a height ht of an upper surface of the second portion 152 b of the temperature control member 152 may be equal to or higher than a height hw of an upper surface of the wafer.

[0069] In FIG5B , if the height ht of the upper surface of the temperature control member 152 is set to be equal to or higher than the height hw of the upper surface of the wafer, the temperature control member 152 becomes thicker and the heat capacity can be increased, and on the other hand, if the height ht of the upper surface of the temperature control member 152 is set to be lower than the height hw of the upper surface of the wafer, the temperature control member 152 becomes thinner and the heat capacity can be reduced, and thus, the temperature can be controlled by changing the thickness of the temperature control member 152 according to the crystal orientation of the wafer, and thus the thickness of the epitaxial layer to be grown can be controlled. That is, in a case having a crystal orientation <110> The heat capacity can be reduced in the region with crystal orientation <100> The heat capacity can be increased in the region of the substrate, thereby enabling the thickness of the epitaxial layer to be grown to be controlled.

[0070] 5C is the same as the embodiment shown in FIG5B , except that a groove g is formed in the bottom surface 110 of the body forming the susceptor 100. That is, the height of the bottom surface 110 of the body provided with the above-mentioned groove g in the region where the first portion 154 a of the temperature control member 154 is provided may be lower than the height of the bottom surface 110 of the body in the region where the wafer is provided.

[0071] Due to the groove g, even in a region where the lower surface of the temperature control member 154 is lower than the lower surface of the wafer, heat can be prevented from being discharged in the edge direction, thereby increasing the amount of heat supplied to the wafer.

[0072] Figure 6 A center C provided on the bottom surface 110 of the susceptor 100 and a temperature control member 150 provided in a ring shape around the center C in some areas of the sidewall 120 are shown.

[0073] The temperature control member 150 may have a plurality of first points P1 having a maximum width W1 in the horizontal direction and a plurality of second points P2 having a minimum width W2 in the horizontal direction, and the first points P1 and the second points P2 may be alternately arranged around the center C thereof in the rotation direction of the base 100. In addition, as Figure 2 As shown, the first point P1 and the second point P2 can be arranged to face the crystal orientation of the wafer respectively. <100> The point and the wafer have crystal orientation <110> point.

[0074] Specifically, in Figure 6 In the embodiment, four first points P1 and four second points P2 may be provided, the first points P1 may be symmetrically arranged with respect to the center C of the base 100 , and the second points P2 may be symmetrically arranged with respect to the center C of the base 100 .

[0075] The susceptor and the epitaxial layer growth apparatus including the susceptor according to the present disclosure may be provided with a temperature control member surrounding the area of the susceptor where the wafer is placed to reduce the heat dissipated between the bottom surface of the susceptor and the edge of the wafer. In particular, in the case of a silicon wafer, the temperature control member may be provided to face the wafer having a crystal orientation. <100> The region of the wafer has a greater width in the horizontal direction to increase heat retention in the corresponding region and thus can promote the crystal orientation <100> The epitaxial layer is grown on an area of the wafer where the epitaxial layer can be grown relatively thin to improve the flatness of the epitaxial layer by uniformly growing the epitaxial layer on the silicon wafer.

[0076] As is apparent from the above description, the susceptor and the epitaxial layer growth apparatus including the susceptor according to the embodiment of the present disclosure are provided with a temperature control member around the area of the susceptor where the wafer is provided, and thus it is possible to reduce the amount of heat dissipated between the bottom surface of the susceptor and the edge of the wafer, and particularly in the case of a silicon wafer, the temperature control member is provided to face the wafer having a crystal orientation. <100> The region of the wafer has a greater width in the horizontal direction to increase heat retention in the corresponding region and thus can promote the crystal orientation <100> The epitaxial layer is grown in an area where the epitaxial layer can be grown relatively thin, thereby allowing the epitaxial layer to grow with uniform thickness on the silicon wafer.

[0077] Although the embodiments of the present disclosure have been explained with reference to the accompanying drawings, the present disclosure is not limited to these embodiments, and various modifications and changes that can be made to the present disclosure without departing from the spirit or scope of the present disclosure are obvious to those skilled in the art. Therefore, the embodiments disclosed in the present disclosure are only for the purpose of describing the present disclosure and are not intended to limit the scope of the present disclosure, and the scope of the present disclosure is not limited by the embodiments. Therefore, it will be understood that the above-mentioned embodiments are merely exemplary and are not intended to limit the present disclosure. The scope of the present disclosure is not limited by the detailed description, but by the claims and their equivalents, and all changes within the scope of the claims and their equivalents should be interpreted as included in the present disclosure.

Claims

1. A base, comprising: a body comprising a bottom surface configured to support a wafer and sidewalls configured to extend upward from a periphery of the bottom surface; as well as A temperature control member is disposed inside the side wall and adjacent to the side wall at an edge of the bottom surface.

2. The base according to claim 1, wherein: The temperature control member is formed of the same material as the main body.

3. The base according to claim 1, wherein: The temperature control member is provided integrally with the main body.

4. The base according to claim 1, wherein: The width of the temperature control member in the horizontal direction is variable.

5. The base according to claim 4, wherein: The temperature control member has a plurality of first points having a maximum width in a horizontal direction and a plurality of second points having a minimum width in the horizontal direction, and the first points and the second points are alternately arranged around the center of the base in a rotation direction of the base.

6. The base according to claim 5, wherein: The number of the first points and the number of the second points are four, the first points are arranged symmetrically with respect to the center of the base, and the second points are arranged symmetrically with respect to the center of the base.

7. The base according to claim 1, wherein: The temperature control member includes a first portion having an annular shape and supported by the bottom surface of the body, and a second portion configured to extend from an upper portion of the first portion toward the side wall of the body.

8. The base according to claim 7, wherein: A height of the bottom surface of the body in a region where the first portion is provided is lower than a height of the bottom surface of the body in a region where the wafer is provided.

9. The base according to claim 7 or claim 8, characterized in that The height of the upper surface of the second portion of the temperature control member is equal to or higher than the height of the upper surface of the wafer.

10. The base according to claim 7 or claim 8, characterized in that The height of the upper surface of the second portion of the temperature control member is lower than the height of the upper surface of the wafer.

11. The base according to claim 1, wherein: the temperature control member has an annular shape having an inverted triangular cross section in a direction from the center of the base toward the outside; and The apex of the inverted triangle cross section is arranged in a direction toward the center of the base.

12. The base according to claim 11, wherein The height of the base of the inverted triangle cross section is equal to or higher than the height of the wafer.

13. The base according to claim 11, wherein: The height of the base of the inverted triangle cross section is lower than the height of the wafer.

14. The base according to claim 5 or claim 6, characterized in that The wafer is a silicon wafer, and the first point faces the wafer in which the crystal orientation of silicon is <100> and the second point faces the region of the wafer where the crystal orientation of silicon is <110> area.

15. An epitaxial layer growth apparatus comprising: chamber; The susceptor of any one of claims 1 to 8, and configured to provide a region in which a wafer is placed within the chamber; pins disposed below the base to support the wafer; as well as A reaction gas supply unit is configured to supply a reaction gas to an upper surface of the wafer to grow an epitaxial layer on the surface of the wafer.

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