Heating device for chemical vapor deposition apparatus, chemical vapor deposition apparatus and installation method thereof

Abstract

This application discloses a heating device for a chemical vapor deposition apparatus, a vapor deposition apparatus, and an installation method, including a first heating element, a second heating element, and a thermal insulating element. The first heating element has a first end and a second end, each connected to the thermal insulating element. The second heating element is disposed around the first heating element. The second heating element has two fixed ends, which are located on the same side and connected to the thermal insulating element. The side of the second heating element away from the fixed ends contacts the surface of the thermal insulating element via a support member. The second heating element is heated to expand radially toward the side away from the fixed ends, and the first heating element is concentric or coaxial with the expanded second heating element. The heating device uniforms the temperature distribution in the temperature field, thereby effectively improving the concentration and thickness uniformity of epitaxial wafers.

Description

[Technical Field]

[0001] The present application relates to the field of semiconductor device manufacturing technology, and more particularly to a heating device for a chemical vapor deposition apparatus, a chemical vapor deposition apparatus, and an installation method thereof. [Background technology]

[0002] Semiconductor CVD (chemical vapor deposition) equipment is the primary equipment used to produce high-quality semiconductor single-crystal thin films, and includes silicon carbide epitaxy equipment, MOCVD, PECVD, and other equipment. Silicon carbide epitaxy and MOCVD equipment in particular are high-tech devices that combine technologies such as vacuum, high temperature, and high-speed rotation. The reaction principle is that a substrate (wafer) is placed on a graphite tray and heated, and reactive gases are flowed over the heated substrate surface, causing a chemical reaction to produce a single-crystal thin film.

[0003] Because temperature has a significant impact on the doping concentration and film thickness uniformity during epitaxial growth, the design of the heating device is extremely important in thin film growth. However, in conventional technologies, the heating device expands when heated, causing uneven temperature distribution at the bottom of the graphite tray, which affects the concentration and film thickness uniformity of the epitaxial wafer. Summary of the Invention

[0004] To overcome the above drawbacks, the present invention provides a heating device for a chemical vapor deposition (CVD) apparatus and a method for installing the same, which can achieve uniform temperature distribution at the bottom of a graphite tray and ensure uniformity in the concentration and thickness of epitaxial wafers grown thereon.

[0005] To achieve the above objectives, the present application adopts the following technical solution. A heating device for a chemical vapor deposition apparatus, comprising: A heat insulating member; a first heating element installed on the heat insulating element; a second heating element disposed on the outer periphery of the first heating element, the second heating element has two drawer fixing ends located on the same side and connected to the heat insulating element, the second heating element has a support member on the side away from the drawer fixing ends, the support member abutting against a surface of the heat insulating element, When heated, the second heating element expands radially away from the fixed end of the drawer, making the first heating element and the expanded second heating element concentric or coaxial. With this design, when the chemical vapor deposition apparatus (also known as an epitaxial apparatus) is undergoing epitaxial growth, the temperature field of the combination of the first heating element and the second heating element is uniform, contributing to the growth of high-quality epitaxial wafers. The second heating element is positioned circumferentially around the first heating element (e.g., sleeved onto the first heating element, with a gap between them). When the second heating element heats and expands, the support member slides along the surface of the insulating member, making the first heating element and the expanded second heating element concentric or coaxial. At room temperature, the first and second heating elements are arranged eccentrically, and during epitaxial growth, they are arranged concentrically, which results in a uniform temperature field on the substrate side and contributes to the growth of high-quality epitaxial wafers (e.g., silicon carbide epitaxy).

[0006] Preferably, the second heating element is eccentrically disposed relative to the first heating element, with the center of the second heating element being offset toward the fixed end of the drawer. At room temperature, the second heating element is eccentrically disposed relative to the first heating element, and after expansion, the second heating element becomes concentric or coaxial with the first heating element to generate a uniform temperature field.

[0007] Furthermore, the distance from the center of the second heating member to the center of the first heating member is an eccentric distance a, and the eccentric distance is 1 mm≦a≦4 mm.

[0008] Preferably, the second heating element has at least one radially extending guide groove that fits into the support element on the side remote from the drawer fixed end.

[0009] Furthermore, one guide groove is arranged, and an extension line of the axis of the guide groove is on the same straight line as the center of the circle of the first heating member and the center of the circle of the second heating member.

[0010] Furthermore, two guide grooves are arranged, and the two guide grooves are installed opposite the two drawer fixed ends.

[0011] Preferably, the heating device further comprises two second heating elements, the two second heating elements being sleeved around the outer periphery of the first heating element.

[0012] Preferably, the first heating element and the second heating element include a graphite material.

[0013] The present application further provides a chemical vapor deposition apparatus, comprising a reaction chamber, a rotary support member provided at the bottom of the reaction chamber, a tray for placing a substrate on the rotary support member, and the above-mentioned heating device disposed within the rotary support member, for heating the substrate.

[0014] The present application further provides a method for installing a heating device in a chemical vapor deposition apparatus, the installation method being applicable to the above-mentioned chemical vapor deposition apparatus, and the installation method includes: determining a center position of the first heating element based on a center position of the tray; determining the positions of the two drawn fixed ends of the second heating element based on the position of the center of the first heating element; determining a position of a second heating element based on the positions of the two drawer fixed ends, and fixing the second heating element; When the second heating element is at room temperature, the distance from the center between the two drawer fixing ends to the center of the first heating element is the sum of the radius of the second heating element and half of the amount of expansion of the second heating element in the radial direction; When the second heating element is heated, it expands away from the fixed end of the pull-out device, making the first and second heating elements concentric or coaxial. At room temperature, the first and second heating elements are eccentrically positioned, but during epitaxial growth, they are concentrically positioned, which makes the temperature field on the substrate side uniform and contributes to the growth of high-quality epitaxial wafers (e.g., silicon carbide epitaxy). [Effects of the Invention]

[0015] In the present application, the second heating element is installed eccentrically, and the two fixed ends of the second heating element are connected to the insulating element and positioned on the same side. When the second heating element is heated, the side away from the fixed end expands radially, making the first heating element and the second heating element concentric or coaxial, resulting in a uniform temperature distribution and effectively improving the concentration and film thickness uniformity of the epitaxial wafer. [Brief explanation of the drawings]

[0016] The drawings are used to understand the technical solutions of the present disclosure, constitute a part of the specification, and are used together with the embodiments of the present disclosure to explain the technical solutions of the present disclosure, but do not constitute limitations on the technical solutions of the present disclosure. The shapes and sizes of each part in the drawings do not reflect actual proportions and are intended to illustrate the contents of the present disclosure. [Figure 1] 1 is a schematic diagram of the structure of a chemical vapor deposition apparatus according to an embodiment of the present application; [Figure 2] 1 is a schematic diagram of the structure of a heating device for a chemical vapor deposition apparatus according to an embodiment of the present application. [Figure 3] 1 is a cross-sectional view of a heating device for a chemical vapor deposition apparatus according to an embodiment of the present application. [Figure 4] FIG. 2 is a top view of a second heating member in an initial state according to an embodiment of the present application. [Figure 5] FIG. 10 is a top view of a second heating member in a heated state according to an embodiment of the present application. [Figure 6] FIG. 2 is a bottom view of a second heating member according to an embodiment of the present application. [Figure 7] FIG. 10 is a bottom view of another example of a second heating element according to an embodiment of the present application. [Figure 8] FIG. 2 is a top view of another embodiment of a heating device for a chemical vapor deposition apparatus according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0017] The above technical solutions will be further described below in combination with specific embodiments. It should be understood that these embodiments are intended to illustrate the present application and do not limit the scope of the present application. The conditions adopted in the embodiments can be further adjusted according to the conditions of specific manufacturers, and the implementation conditions not shown are generally those in conventional experiments.

[0018] Unless otherwise defined, technical or scientific terms used in the embodiments of the present disclosure should have the common meaning understood by a person of ordinary skill in the art to which the present application belongs. Terms such as "first," "second," and the like used in the embodiments of the present disclosure do not denote order, quantity, or importance, but are used only to distinguish between different components. Words such as "comprise" and "include" mean that the element or object preceding the word includes the elements or objects listed thereafter and their equivalents, but do not exclude other elements or objects. Words such as "connected" and "connected" are not limited to physical or mechanical connections, but may also include electrical connections, whether direct or indirect. In this specification, "electrically connected" also includes cases where components are connected via components having some electrical function. There are no particular limitations on "elements having some electrical function" as long as electrical signals can be transmitted and received between the connected components. Examples of "elements having some electrical function" include electrodes, wiring, switching elements such as transistors, and other functional elements such as resistors, inductors, and capacitors. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positions. If the absolute position of the object being described changes, the relative positions may also change accordingly.

[0019] In this application, directions or positional relationships indicated by terms such as "upper," "lower," "inner," and "middle" are based on directions or positional relationships shown in the drawings. These terms are primarily used to better describe the application and its embodiments, and are not used to limit the devices, elements, or components shown to have a particular orientation or to be constructed and operated in a particular orientation.

[0020] This application discloses a heating device for a chemical vapor deposition apparatus, a (chemical) vapor deposition apparatus, and an installation method. The heating device includes a first heating element, at least one second heating element, and an insulating element. The first heating element has a first end and a second end, each connected to the insulating element. The second heating element is disposed around the first heating element, and the second heating element has two drawer fixing ends, each located on the same side and connected to the insulating element. The side of the second heating element away from the drawer fixing end abuts against the surface of the insulating element via a support member. The second heating element is heated to expand radially toward the side away from the drawer fixing end, so that the first heating element becomes concentric or coaxial with the expanded second heating element. The heating device uniforms the temperature distribution in the temperature field, thereby effectively improving the concentration and thickness uniformity of epitaxial wafers. The chemical vapor deposition apparatus is an epitaxial apparatus, such as a silicon carbide epitaxial apparatus. Vapor deposition systems are also called chemical vapor deposition systems.

[0021] Next, the chemical vapor deposition apparatus proposed in this application will be described with reference to FIG.

[0022] The chemical vapor deposition system consists of the following:

[0023] A rotary support member 200 is provided at the bottom of the reaction chamber 100, and a tray 210 for placing a substrate is provided on the rotary support member 200, and a heating device 300 for heating the substrate is provided on the rotary support member 200.

[0024] Next, the heating device of the chemical vapor deposition apparatus proposed in this application will be described with reference to FIGS.

[0025] Referring to FIGS. 2 and 3, a heating device for a chemical vapor deposition apparatus includes: The device includes a heat insulating member 10, a first heating element 20, and a second heating element 30. The first heating element 20 has a first end 21 and a second end 22, and the first end 21 and the second end 22 are respectively connected to the insulating member 10; The second heating element 30 is disposed around the first heating element 20, and has two drawer fixed ends 31, which are located on the same side and connected to the heat insulating element 10, and the side of the second heating element 30 away from the drawer fixed end 31 abuts against the surface of the heat insulating element 10 via a support element 32, and the first heating element 20 and the second heating element 30 are each connected to an external power source and individually controlled thereby; Here, the second heating element 30 is heated so as to expand radially toward the second heating element 30 away from the fixed end 31, so that the first heating element 20 and the expanded second heating element 30 are concentric or coaxial. The first heating element 20 is fixed on the insulating element 10. This design ensures that when the chemical vapor deposition apparatus (also called an epitaxial apparatus) is performing epitaxial growth, the temperature field of the combination of the first heating element 20 and the second heating element 30 is uniform, leading to the growth of high-quality epitaxial wafers. The second heating element 30 is positioned along the circumference of the first heating element 20 (e.g., sleeved over the first heating element 20 with a gap between them). The second heating element 30 expands due to heat, and the support element 32 slides along the surface of the insulating element 10, so that the first heating element 20 and the expanded second heating element 30 are concentric or coaxial. The first heating element 20 and the second heating element 30 are eccentrically arranged at room temperature and concentrically arranged during epitaxial growth, which makes the temperature field on the substrate side uniform and facilitates the growth of high-quality epitaxial wafers (such as silicon carbide epitaxy).

[0026] Specifically, the second heating element 30 and the first heating element 20 of the present invention both contain graphite material, and mainly utilize the fact that graphite expands after being heated at high temperatures. After the second heating element 30 of the present invention is electrically heated, the two fixed ends 31 of the second heating element 30 are connected to the insulating element 10 and are located on the same side, so the side of the second heating element 30 away from the fixed ends 31 expands radially.

[0027] Referring to Figure 4, when the second heating member 30 is in its initial state, the second heating member 30 is positioned eccentrically relative to the first heating member 20, and the center of the second heating member 30 is eccentric to one side of the fixed end 31 of the second heating member 30. The distance from the center of the second heating member 30 to the center of the first heating member 20 is the eccentric distance a, and the eccentric distance is 1 mm ≦ a ≦ 4 mm.

[0028] As shown in Figure 5, when the second heating member 30 expands due to heat, during the substrate heating process, the two drawn-out fixed ends 31 of the second heating member are fixed on the same side, and the side of the second heating member 30 away from the drawn-out fixed end 31 expands radially, causing the first heating member 20 and the second heating member 30 to become concentric or coaxial.

[0029] Below, we will take a graphite second heating element as an example and calculate the expansion amount of the graphite second heating element when heated.

[0030] The amount of expansion of the second heating member ΔL=2a (Equation 1) is expressed as Equation 2 according to the thermal expansion equation. △L=α×△T×L (Formula 2)

[0031] Here, ΔL is the amount of expansion of the second heating element in mm, α is the average thermal expansion coefficient in mm / mm K, ΔT is the temperature difference in K, and L is the original diameter in mm.

[0032] The amount of expansion of the graphite second heating element from room temperature 293K to 2873K is ΔL = 4.4 x 10-6 x (2873 - 293) x 180 = 2.04 mm, and the eccentricity difference between the inner and outer rings is a = 1 / 2 ΔL = 1 mm.

[0033] The two fixed ends of the graphite second heating element are connected to the insulating member and located on the same side, so that after heating, the side of the second heating element farther from the fixed ends expands radially. When the substrate sheet is heated to the required temperature for the process, the temperature of the external heating device is approximately 2873 K, the expansion amount is 2 mm, and the center of the graphite second heating element coincides with the center of the first heating element when it moves 1 mm. The second graphite heating element and the first graphite heating element form a concentric, uniform temperature field (the temperature on the substrate side is uniform, and preferably the temperature difference between the center and end of the substrate side is less than 2°C).

[0034] As shown in Figures 1 and 6 to 7, in this embodiment, at least one guide groove 33 that fits the support member 32 extends radially from one side of the second heating member 30 that is away from the fixed drawn end 31, and by forming the guide groove 33, concentricity between the second heating member 30 and the first heating member 20 after expansion is ensured.

[0035] 4 to 6, in this embodiment, when the guide groove 33a is provided in the second heating member 30, the axis of the guide groove 33a is on the same straight line as the center of the second heating member 30 and the center of the first heating member 20. Specifically, the extension of the line connecting the center of the first heating member 20 and the center of the second heating member 30 is the diameter line of either the first heating member 20 or the second heating member 30. This design helps to improve the concentricity between the second heating member 30 and the first heating member 20 after expansion.

[0036] As a modification of the embodiment shown in Fig. 6, as shown in Fig. 7, the second heating element 30 is provided with two guide grooves 33b, which are arranged opposite to the two fixed ends 31 of the drawer. This design not only improves the concentricity between the expanded second heating element 30 and the first heating element 20, but also ensures the roundness of the expanded second heating element 30.

[0037] Referring to FIG. 8 , this embodiment includes two second heating elements 30, which are sleeved around the first heating element 20. When the two second heating elements 30 are in their initial state, they are eccentrically positioned relative to the first heating element 20. The distance from the center of the second heating element 30a closest to the first heating element 20 to the center of the first heating element 20 is an eccentricity distance a1, and the distance from the center of the second heating element 30b farther from the first heating element 20 to the center of the first heating element 20 is an eccentricity distance a2, where a1 > a2. Similarly, to further ensure concentricity between the second heating element and the first heating element after expansion, a guide groove 33 compatible with the support element 32 is disposed on the side of each second heating element 30 away from the fixed end 31.

[0038] With reference to FIG. 3, in combination with FIGS. 4-5, the present application further provides a method for installing a heating device in a chemical vapor deposition apparatus.

[0039] The installation method first determines the center position of the first heating component 20 through the center position of the tray. In this step, the first heating component 20 is fixed after the center position is determined.

[0040] Next, the positions of the two drawer fixing ends 31 on the second heating member 30 are determined according to the central position of the first heating member 20, and finally the position of the second heating member is determined according to the positions of the two drawer fixing ends 31. In this step, the second heating member is fixed after the positions of the two drawer fixing ends 31 are determined. At room temperature, the second heating member is positioned eccentrically relative to the first heating member.

[0041] When the second heating member is at room temperature, specifically 23°C to 25°C, the distance between the center of the two drawer fixed ends 31 and the center of the first heating member 20 is the sum of the radius of the second heating member 30 and half the amount of expansion of the second heating member 30 in the diameter direction. One of the diameter lines of the second heating member 30 is a line connecting the centers of the first heating member 20 and the second heating member 30. The two drawer fixed ends 31 are arranged symmetrically with respect to the diameter line.

[0042] When the second heating member 30 is heated and expanded, the heating temperature range is 1200°C to 2000°C (preferably 1500°C to 1700°C), and the side of the second heating member 30 away from the drawn-out fixed end 31 is heated and expanded, so that the first heating member 20 and the second heating member 30 become concentric or coaxial.

[0043] As shown in Figure 4, the thermal expansion of the second heating element 30 can be considered as linear expansion of the infinite diameter L of the second heating element, with the direction of expansion indicated by the arrows in the figure. Because one end of the second heating element 30 is a fixed end, the amount of expansion of the side closer to the drawer fixed end 31 of the second heating element 30 is smaller than the amount of expansion of the side farther from the drawer fixed end 31. However, Equation 2 shows that the amount of expansion is the same for materials of equal length, uniform density, and constant temperature rise. Therefore, the eccentricity distance can be determined from the amount of expansion, and the positions of the two drawer fixed ends can be determined. The following is the calculation method for determining the positions of the two drawer fixed ends.

[0044] First, calculate the expansion amount using Equation 2: △L = α × △T × L (Equation 2), then calculate the eccentricity distance using Equation 1: △L = 2a (Equation 1). Finally, determine the positions of the two drawer fixed ends by setting the distance between the center of the first heating element to L / 2 + a, and complete the installation of the second heating element. The diameter of the expanded second heating element is L + 2a.

[0045] Specifically, two second heating members 30 are arranged around the first heating member 20, and the installation method of the second heating member 30b, which is away from the first heating member 20, is the same as the installation method of the second heating member 30a, which is close to the first heating member 20.

[0046] The first heating element 20 and the second heating element 30 described herein do not limit the detailed shapes of the first heating element 20 and the second heating element 30. In other embodiments, a third heating element is further disposed outside the second heating element 30, and the first heating element 20, the second heating element 30, and the third heating element are coaxial or concentric after expansion during the epitaxial process.

[0047] The above embodiments are intended to explain the technical concepts and features of the present application, and are intended to enable those skilled in the art to understand and implement the contents of the present application, but cannot be used to limit the scope of protection of the present application. Any equivalent changes or modifications made in accordance with the spirit of the present application shall fall within the scope of protection of the present application.

Claims

1. A heating device for a chemical vapor deposition apparatus, comprising: A heat insulating member; a first heating member installed on the heat insulating member; a second heating member disposed on the outer periphery of the first heating member, the second heating member has two drawer fixing ends located on the same side and connected to the heat insulating member, the second heating member has a support member on the side away from the drawer fixing ends, the support member abutting against a surface of the heat insulating member, A heating device for a chemical vapor deposition apparatus, characterized in that when heated, the second heating element expands radially away from the fixed end of the drawing, making the first heating element and the expanded second heating element concentric or coaxial.

2. 2. The heating device for a chemical vapor deposition apparatus according to claim 1, wherein the second heating element is installed eccentrically relative to the first heating element, and the center of the second heating element is biased toward the fixed end of the second heating element.

3. 3. The heating device for a chemical vapor deposition apparatus according to claim 2, wherein the distance from the center of the second heating member to the center of the first heating member is an eccentric distance a, and the eccentric distance is 1 mm≦a≦4 mm.

4. 2. The heating device for a chemical vapor deposition apparatus according to claim 1, wherein the second heating member has at least one guide groove extending radially on the side away from the fixed end of the drawer, the guide groove fitting with the support member.

5. 5. The heating device for a chemical vapor deposition apparatus according to claim 4, wherein one guide groove is arranged, and the extension of the axis of the guide groove is on the same straight line as the center of the first heating member and the center of the second heating member.

6. 5. The heating device for a chemical vapor deposition apparatus according to claim 4, wherein two of the guide grooves are disposed, and the two guide grooves are installed opposite the two fixed ends of the drawers.

7. 2. The heating device for a chemical vapor deposition apparatus according to claim 1, further comprising two second heating members, the two second heating members being sleeved around the outer periphery of the first heating member.

8. 2. The heating device for a chemical vapor deposition apparatus according to claim 1, wherein the first heating element has a first end and a second end, the first end and the second end are respectively connected to the insulating element, and the first heating element and the second heating element comprise a graphite material.

9. 10. A chemical vapor deposition apparatus comprising: a reaction chamber; a rotary support member provided at the bottom of the reaction chamber; a tray for placing a substrate on the rotary support member; and a heating device according to any one of claims 1 to 8 disposed within the rotary support member, the heating device being for heating the substrate.

10. A method for installing a heating device in a chemical vapor deposition apparatus, which is applied to the chemical vapor deposition apparatus according to claim 9, comprising the steps of: determining a center position of the first heating member based on a center position of the tray; determining the positions of the two fixed ends of the second heating member based on the position of the center of the first heating member; determining a position of a second heating element based on the positions of the two drawer fixing ends, and fixing the second heating element; When the second heating member is at room temperature, the distance from the center between the two drawer fixing ends to the center of the first heating member is the sum of the radius of the second heating member and half of the amount of expansion of the second heating member in the diameter direction; A method for installing a heating device in a chemical vapor deposition apparatus, characterized in that when the second heating element is heated, it expands toward a side away from the fixed end of the pull-out member, making the first heating element and the second heating element concentric or coaxial.

Images