Graphite disc for MOCVD equipment and MOCVD epitaxial growth method
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGXI ZHAO CHI SEMICON CO LTD
- Filing Date
- 2026-05-13
- Publication Date
- 2026-08-07
AI Technical Summary
载片石墨盘生长过程为旋转状态，从低转速到高转速后回到低转速，在转速变化的过程中，石墨盘上凹槽内的外延片容易出现飞片异常风险
本发明中的一种用于MOCVD设备的石墨盘，通过在凹槽底部设置由外圈向内圈倾斜的斜面，使衬底在旋转过程中相对于水平面呈倾斜状态，凹槽侧壁对衬底施加斜向作用力，该作用力具有向上的分量，能够有效抵抗离心力，从力学上减少飞片发生的可能性；在飞片风险最高的最外圈凹槽外侧上表面设置凸起结构，当衬底因离心力过大或气流扰动而飞出时，凸起结构能够起到物理阻挡作用，将衬底拦截回凹槽内。本发明通过斜面改变衬底受力方向，主动抵抗离心力，同时通过凸起结构形成最后防线，两种机制协同作用，显著降低飞片风险。通过将支撑点设置于斜面上，确保衬底与斜面紧密贴合，使斜面能够有效传递斜向作用力，实现力学干预效果。
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Figure CN122522397A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a graphite disk for MOCVD equipment and a method for MOCVD epitaxial growth. Background Technology
[0002] Metal-organic chemical vapor deposition (MOCVD) equipment is primarily used for the epitaxial growth of LEDs (light-emitting diodes). Existing MOCVD equipment generally uses graphite disks for support and heat conduction. The design requires uniform temperature across all areas of the graphite disk surface to provide an ideal temperature for epitaxial film deposition, thereby achieving the goal of depositing a uniform epitaxial layer. During wafer growth, the wafer is supported on support points within the grooves of the graphite disk. The growth process of the graphite disk is in a rotating state, increasing from low speed to high speed and then returning to low speed. During the speed change, the epitaxial wafer within the grooves of the graphite disk is prone to flyaway anomalies. Flyaway not only renders the epitaxial wafer unusable but can also contaminate other epitaxial wafers, and even cause damage to the graphite disk, generating graphite dust that contaminates the wafer source, severely affecting the yield of epitaxial wafers.
[0003] In existing technologies, some graphite disks employ annular baffle structures to prevent wafer fly-off. However, these annular baffles are continuously positioned along the edge of the disk, significantly impacting airflow distribution and potentially affecting the uniformity of epitaxial growth. Additionally, some graphite disks utilize a curved bottom design, but this curved design primarily addresses temperature uniformity issues caused by wafer warping at high temperatures, rather than providing mechanical intervention for wafer fly-off problems.
[0004] Therefore, how to effectively prevent the phenomenon of wafer flying while not affecting the uniformity of epitaxial growth has become a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide a graphite disk for MOCVD equipment and an MOCVD epitaxial growth method, which improves the stability of epitaxial wafers during the growth process and reduces the risk of epitaxial wafers flying out of the placement groove due to changes in rotation speed and airflow.
[0006] To address the aforementioned technical problems, the present invention provides, in a first aspect, a graphite disk for an MOCVD device, comprising a graphite disk body, wherein the graphite disk body has a plurality of grooves for placing a substrate; the bottom of each groove has a plurality of support points for supporting the substrate; the plurality of grooves are arranged in at least two concentric rings on the graphite disk body from the center outward; within the same ring, in each pair of adjacent grooves, at least one groove has a slope at its bottom, the slope being inclined from the outer ring of the groove towards the inner ring, for applying an oblique force to the substrate to resist centrifugal force when the graphite disk rotates, the support points within the groove being disposed on the slope; and / or, at least the outermost groove has a protruding structure on its outer upper surface for physically blocking the substrate when it flies out.
[0007] As an improvement to the above scheme, the angle between the inclined plane and the horizontal plane is 0.5°~15°.
[0008] As an improvement to the above scheme, the slope angle at the bottom of the groove in the inner ring is smaller than the slope angle at the bottom of the groove in the outer ring.
[0009] As an improvement to the above scheme, the height of the protrusion structure is 30μm~3000μm.
[0010] As an improvement to the above solution, two or more protrusions are provided on the outer upper surface of each groove; the protrusions are provided on the outer side upper surface of each groove and are located directly above the sidewall of the groove.
[0011] As an improvement to the above solution, each of the grooves has a slope at its bottom.
[0012] As an improvement to the above solution, the support points are unevenly distributed at the bottom of the groove.
[0013] As an improvement to the above solution, the plurality of grooves are arranged in three concentric rings on the graphite disk body, from the center outward: an inner ring, a middle ring, and an outer ring. The slope angle at the bottom of the groove in the inner ring is smaller than that at the bottom of the groove in the middle ring, and the slope angle at the bottom of the groove in the middle ring is smaller than that at the bottom of the groove in the outer ring.
[0014] As an improvement to the above solution, the protrusion structure is only provided on the upper surface of the outermost semicircular area of the outermost groove.
[0015] In a second aspect, the present invention provides an MOCVD epitaxial growth method using the aforementioned graphite disk, comprising the following steps: Multiple substrates are placed in multiple grooves of the graphite disk, with the substrates supported on support points at the bottom of the grooves. The graphite disk is placed in the MOCVD reaction chamber and driven to rotate around its axis. A reaction gas is introduced into the reaction chamber, and epitaxial growth is performed on the surface of the substrate. During the rotation of the graphite disk, the groove with an inclined surface causes the substrate to be tilted relative to the horizontal plane. The sidewall of the groove applies an oblique force to the substrate to resist centrifugal force. When the graphite disk is provided with a protruding structure, the protruding structure physically blocks the substrate when it flies out of the groove.
[0016] The beneficial effects of implementing this invention are as follows: This invention discloses a graphite disk for MOCVD equipment. By incorporating a sloping surface at the bottom of the groove, extending from the outer to the inner ring, the substrate is tilted relative to the horizontal plane during rotation. The groove sidewalls apply an upward-biased force to the substrate, effectively resisting centrifugal force and mechanically reducing the likelihood of wafer fly-off. A raised structure is provided on the outer surface of the outermost groove, where the risk of wafer fly-off is highest. When the substrate flies off due to excessive centrifugal force or airflow disturbance, the raised structure acts as a physical barrier, intercepting the substrate and drawing it back into the groove. This invention actively resists centrifugal force by altering the direction of force on the substrate with the sloping surface, while simultaneously forming a final line of defense with the raised structure. These two mechanisms work synergistically to significantly reduce the risk of wafer fly-off. By placing the support points on the sloping surface, a tight fit between the substrate and the surface is ensured, allowing the sloping surface to effectively transmit the sloping force and achieve a mechanical intervention effect.
[0017] This invention discloses an MOCVD epitaxial growth method that tilts the substrate using a slanted surface. During rotation, this slanted force actively resists centrifugal force, reducing the risk of wafer fly-off from a mechanical perspective. Simultaneously, a raised structure provides a final physical interception when the substrate flies off, forming a double protection. This method effectively solves the wafer fly-off problem during rotational speed changes, improving process stability and production yield. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the structure of a graphite disk for an MOCVD device in an embodiment of this application; Figure 2 This is a cross-sectional view of a graphite disk with a beveled groove in an MOCVD device according to an embodiment of this application; Figure 3 This is a cross-sectional view of a non-sloping groove in a graphite disk for an MOCVD device according to an embodiment of this application; Figure 4 This is a partial top view of a groove in a graphite disk for an MOCVD device according to an embodiment of this application; Figure 5This is a partial cross-sectional view of a groove in a graphite disk for an MOCVD device according to an embodiment of this application.
[0019] The reference numerals in the attached drawings are explained as follows: 100, graphite disk body; 200, groove; 210, inclined surface; 220, raised structure. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.
[0021] Example 1: See Figure 1 , Figure 1 This is a schematic diagram of the structure of a graphite disk for an MOCVD device in an embodiment of this application; Figure 2 This is a cross-sectional view of a graphite disk with a beveled groove in an MOCVD device according to an embodiment of this application; Figure 3 This is a cross-sectional view of a non-sloping groove in a graphite disk for an MOCVD device according to an embodiment of this application. As shown in the figure, the graphite disk includes a graphite disk body 100, on which a plurality of grooves 200 for placing a substrate are provided; the bottom of each groove 200 is provided with a plurality of support points for supporting the substrate; the plurality of grooves 200 are arranged in at least two coaxial rings from the center outward on the graphite disk body; within the same ring, in every two adjacent grooves 200, one groove 200 has a slope 210 at its bottom, the slope 210 being inclined from the outer ring to the inner ring of the groove 200, used to apply a sloping force to the substrate to resist centrifugal force when the graphite disk rotates. The support point is set on the inclined surface 210. By setting the inclined surface 210 at the bottom of the groove 200, which slopes from the outer ring to the inner ring, the substrate is tilted relative to the horizontal plane during rotation. The sidewall of the groove 200 applies an oblique force to the substrate, which has an upward component and can effectively resist centrifugal force, mechanically reducing the possibility of wafer fly-off. The method of setting at least one inclined surface 210 in every two adjacent grooves 200 ensures the anti-wafer fly-off effect, simplifies the processing technology, and helps maintain the uniformity of the airflow field without affecting the epitaxial growth quality. The alternating arrangement of the spaced inclined surfaces 210 and the plane ensures the overall anti-wafer fly-off effect while diversifying the stress state of the substrate and reducing the risk of resonance. A reliable anti-wafer fly-off effect is achieved at a low cost, taking into account both process feasibility and growth uniformity.
[0022] See Figure 4 and Figure 5 , Figure 4 This is a partial top view of a groove 200 in a graphite disk for an MOCVD device according to an embodiment of this application; Figure 5This is a partial cross-sectional view of a groove 200 in a graphite disk for an MOCVD device according to an embodiment of this application; Furthermore, in this embodiment, a raised structure 220 is provided on the outer upper surface of the outermost groove 200 to physically block the substrate when it flies out. By placing the raised structure 220 in the area with the highest risk of substrate ejection, the raised structure 220 can physically block the substrate when it flies out due to excessive centrifugal force or airflow disturbance, intercepting it back into the groove 200. The raised structure 220 is only placed in the outer ring, causing minimal interference to the airflow field and not affecting the uniformity of epitaxial growth. This invention actively resists centrifugal force by changing the direction of force on the substrate through the inclined surface 210, while simultaneously forming a final line of defense through the raised structure 220. The synergistic effect of these two mechanisms significantly reduces the risk of substrate ejection.
[0023] Furthermore, in this embodiment, the angle of the inclined surface 210 at the bottom of the groove 200 in the inner ring is smaller than the angle of the inclined surface 210 at the bottom of the groove 200 in the outer ring. When the graphite disk rotates, the linear velocity of the outer ring is greater than that of the inner ring, resulting in a greater centrifugal force on the outer ring substrate. This invention sets different inclined surface 210 angles according to the magnitude of the centrifugal force. The outer ring uses a larger angle to provide a stronger oblique force, while the inner ring uses a smaller angle to avoid excessive tilting, achieving a refined match for the anti-flying effect. Through gradient design, the stress state of each layer of substrate is matched with the centrifugal force distribution, avoiding excessive intervention in the inner ring or insufficient intervention in the outer ring, resulting in a better overall anti-flying effect.
[0024] Preferably, the angle between the inclined plane 210 and the horizontal plane is 0.5° to 15°. When the graphite disk rotates, if the angle is too small, the oblique force is insufficient, and the anti-flying effect is not obvious; if the angle is too large, the substrate tilts excessively, which may affect the airflow distribution and temperature uniformity. The angle range of 0.5° to 15° can cover the centrifugal force resistance requirements in most process scenarios.
[0025] See Figure 4 Furthermore, in this embodiment, each groove 200 has two or more protrusions 220 on its outer upper surface; the protrusions 220 are located on the outermost upper surface of each groove 200, directly above the sidewall of the groove 200. Each groove 200 has two or more protrusions, forming a multi-point blocking structure. Even if one protrusion fails, the others can still function, improving the reliability of the anti-flying plate. By dispersing the protrusions 220, blocking is only placed at the most vulnerable locations, resulting in less interference with airflow and helping to maintain uniform epitaxial growth.
[0026] Preferably, the height of the protrusion structure 220 is 30μm to 3000μm. This allows it to cover common substrate thicknesses, ensuring that the protrusion structure 220 can effectively prevent the substrate from flying out.
[0027] Preferably, the support points are unevenly distributed at the bottom of the groove 200. During epitaxial growth, the epitaxial wafer may warp; the unevenly distributed support points can better adapt to the warping of the substrate, providing more stable support. The uneven distribution of support points can create more complex airflow channels at the bottom of the groove 200, which is beneficial for the uniform distribution of reactant gases and improves the quality of epitaxial growth. The unevenly distributed support points can reduce the contact area between the support points and the substrate while maintaining stable support, which is beneficial for uniform heat conduction.
[0028] See Figure 1 Furthermore, in this embodiment, the plurality of grooves 200 are arranged in three concentric rings—an inner ring, a middle ring, and an outer ring—outward from the center of the graphite disk body 100. The angle of the slope 210 at the bottom of the groove 200 in the inner ring is smaller than that in the middle ring, and the angle of the slope 210 at the bottom of the groove 200 in the middle ring is smaller than that in the outer ring. The three-ring structure divides the disk surface into three centrifugal force zones, and the angle of the slope 210 is precisely matched with the magnitude of the centrifugal force, ensuring the anti-flying effect while minimizing the impact on the airflow field and growth uniformity. The three-ring gradient design provides more flexibility for process adjustment, allowing the angle of the slope 210 to be independently optimized according to the growth characteristics of different rings.
[0029] This embodiment provides a second aspect of an MOCVD epitaxial growth method, which uses the aforementioned graphite disk and includes the following steps: Multiple substrates are placed in multiple grooves 200 of the graphite disk, so that the substrates are supported on the support points at the bottom of the grooves 200; The graphite disk is placed in the MOCVD reaction chamber and driven to rotate around its axis. A reaction gas is introduced into the reaction chamber, and epitaxial growth is performed on the surface of the substrate. During the rotation of the graphite disk, the groove 200 with the inclined surface 210 causes the substrate to be tilted relative to the horizontal plane. The sidewall of the groove 200 applies an oblique force to the substrate to resist centrifugal force. When the graphite disk is provided with the protrusion structure 220, the protrusion structure 220 physically blocks the substrate when it flies out of the groove 200.
[0030] In this embodiment, the inclined surface 210 actively resists centrifugal force as the first line of defense, while the raised structure 220 physically blocks it as the second line of defense, forming a dual protection mechanism. When the inclined surface 210 is insufficient to completely counteract the centrifugal force, the raised structure 220 can provide a final interception at the critical moment when the substrate flies out, ensuring the stability of the process. In this invention, the inclined surface 210 design has minimal impact on the airflow field, and the raised structure 220 is only locally located in the outermost semi-circular region, causing far less interference to the airflow field than a continuous annular baffle. Simultaneously, the tilted substrate may improve the flow path of the reactive gas on the substrate surface, which is beneficial for improving the uniformity of epitaxial growth. This method can also significantly reduce the occurrence rate of flyaway wafers, thereby reducing the risk of process interruption, improving the yield of single-furnace production, and reducing production costs. It also reduces the risk of graphite disk breakage, extends the service life of graphite disks, reduces equipment maintenance frequency, and reduces graphite powder contamination caused by graphite disk breakage, resulting in significant economic benefits.
[0031] Example 2: This embodiment is the same as Embodiment 1 except for the following distinguishing features.
[0032] Furthermore, in this embodiment, each of the grooves 200 has a slope 210 at its bottom. This maximizes the anti-flying chip protection across the entire disk surface, ensuring that all substrates are subjected to a sloped force to resist centrifugal force, completely eliminating the risk of flying chips that may exist in grooves 200 without slopes 210; it eliminates the need to distinguish between grooves 200 with slopes 210 and flat grooves 200, resulting in good processing consistency; it also promotes the uniform distribution of airflow and heat fields, avoiding local disturbances that may be caused by the alternation of slopes 210 and flat surfaces. This solution is suitable for process scenarios with extremely high requirements for anti-flying chip protection.
[0033] Example 3: This embodiment is the same as Embodiment 1 except for the following distinguishing features.
[0034] Furthermore, in this embodiment, a raised structure 220 is provided on the upper surface of the outer semicircular region of each ring of the groove 200. This achieves full-disk anti-flying protection, and the inner and middle ring grooves 200 also receive physical blocking protection when the centrifugal force is small but the airflow is disturbed. Each ring of raised structures is located in the outer semicircular region, precisely targeting the direction in which the substrate of each ring is most likely to fly out, resulting in high blocking efficiency. Unlike continuous annular baffles, localized raised structures have less interference with the airflow field and do not affect the uniformity of epitaxial growth. This solution is suitable for high-end epitaxial processes with extremely high yield requirements.
[0035] As described above, the graphite disk for MOCVD equipment in this invention utilizes a sloped surface at the bottom of the groove, extending from the outer to the inner ring. This causes the substrate to be tilted relative to the horizontal plane during rotation. The sidewalls of the groove exert an oblique force on the substrate, which has an upward component, effectively resisting centrifugal force and mechanically reducing the possibility of wafer fly-off. A raised structure is provided on the outer surface of the outermost groove, where the risk of wafer fly-off is highest. When the substrate flies off due to excessive centrifugal force or airflow disturbance, the raised structure acts as a physical barrier, intercepting the substrate and pulling it back into the groove. This invention actively resists centrifugal force by changing the direction of force on the substrate through the sloped surface, while simultaneously forming a final line of defense through the raised structure. These two mechanisms work synergistically to significantly reduce the risk of wafer fly-off. By placing the support points on the sloped surface, a tight fit between the substrate and the sloped surface is ensured, allowing the sloped surface to effectively transmit the oblique force and achieve a mechanical intervention effect.
[0036] This invention discloses an MOCVD epitaxial growth method that tilts the substrate using a slanted surface. During rotation, this slanted force actively resists centrifugal force, reducing the risk of wafer fly-off from a mechanical perspective. Simultaneously, a raised structure provides a final physical interception when the substrate flies off, forming a double protection. This method effectively solves the wafer fly-off problem during rotational speed changes, improving process stability and production yield.
[0037] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.
Claims
1. A graphite disk for an MOCVD equipment, characterized in that, The device includes a graphite disk body, which has multiple grooves for placing a substrate; the bottom of each groove has multiple support points for supporting the substrate. The plurality of grooves are arranged in at least two coaxial rings on the graphite disk body from the center outward; within the same ring, at least one of the two adjacent grooves has an inclined surface at the bottom, the inclined surface is inclined from the outer ring of the groove to the inner ring, and is used to apply an oblique force to the substrate to resist centrifugal force when the graphite disk rotates; the support point in the groove is arranged on the inclined surface. And / or, at least the outermost groove has a raised structure on its upper outer surface for physical blocking when the substrate flies out.
2. The graphite disk for MOCVD equipment according to claim 1, characterized in that, The angle between the inclined plane and the horizontal plane is 0.5° to 15°.
3. The graphite disk for MOCVD equipment according to claim 1, characterized in that, The slope angle at the bottom of the groove in the inner ring is smaller than the slope angle at the bottom of the groove in the outer ring.
4. The graphite disk for MOCVD equipment according to claim 1, characterized in that, The height of the protruding structure is 30μm~3000μm.
5. The graphite disk for MOCVD equipment according to claim 1, characterized in that, Each groove has two or more protruding structures on its outer upper surface; the protruding structures are located on the outer side of the upper surface of each groove and are located directly above the sidewall of the groove.
6. The graphite disk for MOCVD equipment according to claim 1, characterized in that, Each of the grooves has a beveled surface at its bottom.
7. The graphite disk for MOCVD equipment according to claim 1, characterized in that, The support points are unevenly distributed at the bottom of the groove.
8. The graphite disk for MOCVD equipment according to claim 1, wherein the plurality of grooves are arranged in three concentric rings from the center outward on the graphite disk body: an inner ring, a middle ring, and an outer ring; the slope angle of the bottom of the groove in the inner ring is smaller than the slope angle of the bottom of the groove in the middle ring, and the slope angle of the bottom of the groove in the middle ring is smaller than the slope angle of the bottom of the groove in the outer ring.
9. The graphite disk for MOCVD equipment according to claim 8, characterized in that, The protruding structure is only provided on the upper surface of the outermost semi-circular area of the outermost groove.
10. A method for MOCVD epitaxial growth, characterized in that, The graphite disk according to any one of claims 1 to 9 comprises the following steps: Multiple substrates are placed in multiple grooves of the graphite disk, with the substrates supported on support points at the bottom of the grooves. The graphite disk is placed in the MOCVD reaction chamber and driven to rotate around its axis. A reaction gas is introduced into the reaction chamber, and epitaxial growth is performed on the surface of the substrate. During the rotation of the graphite disk, the groove with an inclined surface causes the substrate to be tilted relative to the horizontal plane. The sidewall of the groove applies an oblique force to the substrate to resist centrifugal force. When the graphite disk is provided with a protruding structure, the protruding structure physically blocks the substrate when it flies out of the groove.