Semiconductor epitaxial growth assembly, epitaxial growth device and epitaxial growth process

Abstract

The invention relates to a semiconductor epitaxial growth assembly, an epitaxial growth device and an epitaxial growth process. The semiconductor epitaxial growth assembly comprises a wafer holder; the lower half-moon structure is provided with an assembling surface, and a wafer support is embedded in the assembling surface; the assembly surface faces process gas for epitaxial growth, and a preset angle is formed between the assembly surface and the gas flow direction of the process gas for epitaxial growth, so that the wafer supported by the wafer holder is inclined. When the wafer is placed in the high-temperature reaction furnace chamber, because the wafer is inclined, the wafer does not have a windward side along the airflow direction, so that particles in the furnace chamber are not easy to attach to the surface of the wafer, and the quality of the wafer is improved; moreover, the wafer is inclined, so that the contact area between the wafer and the process gas is increased, the gas flow rate of the process gas is reduced, and the thickness uniformity of a film layer formed by epitaxial growth is higher; in addition, the wafer is inclined so that the temperature of the downstream end of the airflow is slightly higher than that of the upstream end, the defect that the effective component concentration of the downstream end of the airflow is lower than that of the upstream end is overcome, and the wafer growth rate is more balanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a semiconductor epitaxial growth assembly, an epitaxial growth device and an epitaxial growth process. BACKGROUND

[0002] Silicon carbide epitaxial growth takes high-temperature chemical vapor deposition (CVD) as the core, and through steps such as substrate cleaning, high-temperature annealing, precursor deposition, and temperature reduction and wafer taking, a single crystal thin film with lattice matching is epitaxially grown on the surface of a SiC substrate under an environment of 1500-1700℃, and precise control of parameters such as temperature and gas ratio is the key to ensuring the quality of the epitaxial layer.

[0003] The core of the semiconductor epitaxial growth assembly includes a wafer holder and a lower half moon graphite piece, and the wafer holder and the lower half moon graphite piece are key components for ensuring the uniformity and crystal quality of the epitaxial layer. The wafer holder takes high-purity graphite as the base and carries the wafer, can uniformly transfer heat to the substrate to ensure the consistency of the epitaxial growth temperature, and can also isolate the corrosive gas to avoid impurity pollution of the wafer. The lower half moon graphite piece is an arc structure, which is a supporting piece matched with the wafer holder, can assist in optimizing the gas flow distribution of the reaction chamber, improve the utilization rate of the precursor, and can also enhance the stability of the thermal field and reduce the defects of the epitaxial layer caused by temperature difference and gas flow disturbance. The two work together to support efficient and stable epitaxial deposition process.

[0004] However, the current semiconductor epitaxial growth assembly still needs to be improved. SUMMARY

[0005] The technical problem solved by the present application is how to improve the semiconductor epitaxial growth assembly to improve the stability and uniformity of epitaxial growth.

[0006] To solve the above technical problems, the present application provides a semiconductor epitaxial growth assembly, which comprises: a wafer holder adapted to hold a wafer; a lower half moon structure having an assembly surface, the assembly surface being embedded with the wafer holder; the assembly surface is directed towards the process gas of epitaxial growth, and the assembly surface and the gas flow direction of the process gas of epitaxial growth form a preset angle to make the wafer held by the wafer holder inclined.

[0007] Optionally, the included angle between the assembly surface and the gas flow direction of the process gas of epitaxial growth ranges from 0.5° to 5°.

[0008] Optionally, the wafer holder has a wafer holder groove facing away from the lower half moon structure; the depth of the wafer holder groove is equal everywhere.

[0009] Optionally, the thickness of the wafer holder at the bottom of the wafer holder groove is equal everywhere.

[0010] Optionally, the top surface of the wafer holder on the sidewall of the wafer holder groove is coplanar with the assembly surface.

[0011] Optionally, the depth of the wafer support groove is not less than the thickness of the wafer.

[0012] Optionally, the wafer holder rotates about an axis perpendicular to the assembly surface.

[0013] Accordingly, this embodiment of the invention also provides an epitaxial growth apparatus, comprising: a semiconductor epitaxial growth component, the semiconductor epitaxial growth component as described in this embodiment of the invention; a reactor, the furnace cavity of the reactor being adapted to accommodate the semiconductor epitaxial growth component, the reactor including an inlet and an outlet, the direction of the inlet pointing to the outlet being the airflow direction.

[0014] Optionally, the epitaxial growth apparatus includes: a plurality of semiconductor epitaxial growth components, wherein the angle between the assembly surface of each semiconductor epitaxial growth component and the airflow direction is different.

[0015] Accordingly, embodiments of the present invention also provide an epitaxial growth process, comprising: using an epitaxial growth apparatus as described in any one of the embodiments of the present invention, and introducing reaction gas through the gas inlet of the reactor.

[0016] Compared with the prior art, the technical solution of the embodiments of the present invention has the following beneficial effects:

[0017] In the semiconductor epitaxial growth assembly of the present invention, the assembly surface of the lower crescent structure is at a preset angle to the flow direction of the epitaxial growth process gas, causing the wafer supported by the wafer holder to tilt. When the wafer is placed in a high-temperature reaction furnace for epitaxial growth, due to the tilt of the wafer, the slope of the tangent of the wafer, which warps due to the high temperature along the flow direction of the process gas, changes approximately monotonically. This eliminates the direct airflow impact on the wafer's frontal surface, making it less likely for particles in the furnace to adhere to the wafer's surface, reducing surface defects and improving wafer quality. Furthermore, the tilt of the wafer increases the contact area between the wafer and the process gas, reduces the gas flow rate, and lowers the possibility of turbulence caused by excessive gas flow, resulting in a more uniform epitaxial growth rate and higher uniformity of the epitaxial film thickness. In addition, the tilt of the wafer causes the temperature at the downstream end of the epitaxial growth process gas flow to be slightly higher than the upstream end, thereby compensating for the lower effective component concentration at the downstream end of the epitaxial growth process, resulting in a more balanced wafer growth rate. Attached Figure Description

[0018] Figure 1 This is a schematic cross-sectional view of a semiconductor epitaxial growth assembly before it enters the furnace cavity.

[0019] Figure 2 This is a schematic cross-sectional view of a semiconductor epitaxial growth assembly in the furnace chamber.

[0020] Figure 3 This is a cross-sectional structural diagram of a semiconductor epitaxial growth assembly according to an embodiment of the present invention;

[0021] Figure 4 This is a schematic cross-sectional view of the semiconductor epitaxial growth component in the state of being introduced with process gas, according to an embodiment of the present invention.

[0022] Figure 5 This is a three-dimensional structural schematic diagram of a semiconductor epitaxial growth component according to an embodiment of the present invention. Detailed Implementation

[0023] As can be seen from the background technology, existing semiconductor epitaxial growth components still have shortcomings. The reasons for these problems are now analyzed in conjunction with the accompanying drawings:

[0024] Please refer to Figure 1 A semiconductor epitaxial growth assembly includes: a wafer holder 100 adapted to support a wafer 101; a lower crescent structure 102 having an assembly surface 102a in which the wafer holder 100 is embedded; the assembly surface 102a facing the process gas of epitaxial growth, and the gas flow direction X of the process gas of epitaxial growth being parallel to the surface of the assembly surface 102a.

[0025] The lower crescent structure 102 has a lower crescent groove located within the assembly surface 102a and facing the wafer holder 100.

[0026] The thickness of the lower crescent structure 102 at the bottom of the lower crescent groove is equal everywhere.

[0027] The semiconductor epitaxial growth assembly is suitable for the epitaxial growth of silicon carbide. Specifically, the temperature of the reaction chamber for the silicon carbide epitaxial growth is maintained at 700℃~1000℃.

[0028] The process gases for semiconductor epitaxial growth include hydrogen, ethylene, and trichlorosilane. The flow rate of the process gases for semiconductor epitaxial growth ranges from 80 SLM to 120 SLM.

[0029] Please refer to Figure 2 At the moment when the wafer 101 enters the furnace cavity, the high temperature of the furnace cavity can easily cause the wafer 101 to warp. The airflow direction X of the epitaxial growth process gas is parallel to the surface of the assembly surface 102a, thereby making the wafer 101 form a windward surface A.

[0030] The windward surface A of wafer 101 refers to the local area of ​​wafer 101 that is first impacted when the process gas flows along the direction X from the inlet to the outlet. The angle between the tangent of wafer 101 in the local area and the airflow direction X is close to 90°.

[0031] Driven by the flow of process gas, particles inside the furnace cavity will adhere to the surface of the windward side A, causing a trapping defect in the wafer 101. Furthermore, the flow rate of the process gas for silicon carbide epitaxial growth is relatively large, while the furnace cavity is relatively small, making it easy for turbulence to form on the surface of the wafer 101, thus affecting the stability of epitaxial growth. In addition, as the effective components are deposited at the front end of the process gas flow, the content of effective components in the process gas at the downstream end decreases, reducing the epitaxial growth rate and causing uneven thickness of the film layer formed by the epitaxial growth process.

[0032] To address the aforementioned technical problem, the present invention provides a semiconductor epitaxial growth assembly, comprising: a wafer holder adapted to support a wafer; a lower crescent structure having an assembly surface in which the wafer holder is embedded; the assembly surface facing the process gas of epitaxial growth, and the assembly surface forming a predetermined angle with the airflow direction of the process gas of epitaxial growth to tilt the wafer supported by the wafer holder.

[0033] In the semiconductor epitaxial growth assembly of this invention, the assembly surface of the lower crescent structure is at a preset angle to the flow direction of the epitaxial growth process gas, causing the wafer supported by the wafer holder to tilt. When the wafer is placed in a high-temperature reaction furnace for epitaxial growth, due to the tilt of the wafer, the slope of the tangent of the wafer, which warps due to the high temperature along the flow direction of the process gas, changes approximately monotonically. This eliminates the direct airflow impact on the wafer's frontal surface, making it less likely for particles in the furnace to adhere to the wafer's surface, reducing surface defects and improving wafer quality. Furthermore, the tilt of the wafer increases the contact area between the wafer and the process gas, reduces the gas flow rate, and lowers the possibility of turbulence caused by excessive gas flow, resulting in a more uniform epitaxial growth rate and higher uniformity of the epitaxial film thickness. In addition, the tilt of the wafer causes the temperature at the downstream end of the epitaxial growth process gas flow to be slightly higher than the upstream end, thus compensating for the lower effective component concentration at the downstream end of the epitaxial growth process, resulting in a more balanced wafer growth rate.

[0034] To make the above-mentioned objectives, features and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0035] Please refer to Figures 3 to 5The semiconductor epitaxial growth assembly includes a wafer holder 200, which is adapted to support a wafer 201.

[0036] In epitaxial growth processes, the wafer holder 200 is a core process component that supports and fixes the wafer 201, and provides uniform heat conduction and stable support for the wafer 201. It is widely used in high-temperature chemical vapor deposition (CVD) epitaxial equipment for materials such as silicon carbide and silicon.

[0037] The wafer holder 200 has a wafer holder groove adapted to accommodate the wafer 201. The depth of the wafer holder groove is not less than the thickness of the wafer 201.

[0038] For example, such as Figure 3 As shown, the depth of the wafer holder groove is the vertical distance from the upper surface of the wafer holder 200 to the bottom of the wafer holder groove. The thickness of the wafer 201 is the vertical distance between the upper surface and the lower surface of the wafer 200.

[0039] The depth of the wafer holder groove of the wafer holder 200 is adapted to the thickness of the wafer 201. When the wafer 201 is placed in the wafer holder groove of the wafer holder 200, the upper surface of the wafer 201 is not higher than the upper surface of the wafer holder 200.

[0040] The thickness of the wafer 200 is the same everywhere, and correspondingly, the depth of the wafer support groove is the same everywhere.

[0041] Specifically, in some embodiments of the present invention, the depth of the wafer support groove ranges from 0.3 mm to 0.6 mm.

[0042] The wafer holder 200 has high temperature resistance. Specifically, in some embodiments of the present invention, the wafer holder 200 is made of graphite.

[0043] Please continue to refer to this. Figure 3 The thickness of the wafer holder 200 at the bottom of the wafer holder groove is uniform throughout. The thickness of the wafer holder 200 at the bottom of the wafer holder groove is the dimension of the wafer holder 200 at the bottom of the wafer holder groove along the direction perpendicular to the surface of the wafer holder 200.

[0044] For example, such as Figure 3 and Figure 4As shown, the wafer tray 200 includes a supporting portion 2001 and abutment portions 2002 located on both sides of the supporting portion 2001. The top surface of the abutment portions 2002 is higher than the top surface of the supporting portion 2001. The supporting portion 2001 and the two abutment portions 2002 together form the wafer tray groove. The wafer tray 200 at the bottom of the wafer tray groove is the supporting portion 2001. The thickness of the wafer tray 200 at the bottom of the wafer tray groove is the dimension of the supporting portion 2001 along the direction perpendicular to the surface of the wafer tray 200. Specifically, the thickness of the supporting portion 2001 is equal everywhere.

[0045] The wafer holder 200 at the bottom of the wafer holder groove has a uniform thickness and a uniform mass distribution. When the wafer holder 200 rotates vertically along the axis, it runs more smoothly. At the same time, the uniform thickness of the wafer holder 200 at the bottom of the wafer holder groove ensures uniform heat conduction, reduces local temperature differences, and improves process consistency.

[0046] Please refer to Figures 3 to 5 The semiconductor epitaxial growth assembly includes a lower crescent structure 202, the lower crescent structure 202 having an assembly surface 202a, and the wafer holder 200 embedded in the assembly surface 202a.

[0047] The wafer holder 200 is embedded within the assembly surface 202a. This embedding method can physically limit the wafer holder 200, preventing it from shifting or shaking during high-speed rotation, airflow disturbance, or slight equipment vibration. At the same time, the embedding of the wafer holder 200 within the assembly surface 202a ensures the consistency of the wafer holder 200's position each time it is installed, thus ensuring process repeatability.

[0048] The lower crescent structure 202 has a lower crescent groove located within the assembly surface 202a and facing the wafer holder 200.

[0049] The depth of the lower crescent groove is adapted to the maximum thickness of the wafer holder 200, and the depth of the lower crescent groove is equal everywhere.

[0050] The thickness of the lower crescent structure at the bottom of the lower crescent groove is not uniform everywhere. For an example, please refer to... Figure 3 and Figure 4 Along the airflow direction X of the process gas, the thickness of the lower half-moon structure at the bottom of the lower half-moon groove gradually decreases.

[0051] Compared to setting the thickness of the lower half-moon structure at the bottom of the lower half-moon groove to be equal everywhere and setting the thickness of the wafer holder at the bottom of the wafer holder groove to gradually decrease along the airflow direction, this embodiment of the invention sets the thickness of the lower half-moon structure at the bottom of the lower half-moon groove to gradually decrease along the airflow direction and sets the thickness of the wafer holder at the bottom of the wafer holder groove to be equal everywhere. This makes the mass distribution of the wafer holder 200 at the bottom of the wafer holder groove uniform, and the operation is more stable when the wafer holder 200 rotates vertically along the axis. At the same time, the uniform thickness of the wafer holder 200 at the bottom of the wafer holder groove makes the heat conduction of the wafer holder 200 uniform, reduces local temperature differences, and improves process consistency.

[0052] Please refer to the reference. Figure 3 and Figure 4 The assembly surface 202a faces the process gas of epitaxial growth, and the assembly surface 202a and the airflow direction X of the process gas of epitaxial growth are at a preset angle θ so that the wafer 201 supported by the wafer holder 200 is tilted.

[0053] Please refer to Figure 4 When the wafer 201 is placed in a high-temperature reaction furnace for epitaxial growth, the slope of the tangent of the wafer 201, which warps due to the high temperature along the airflow direction X of the process gas, changes approximately monotonically. This means that the wafer 201 does not have a windward surface that is directly impacted by the airflow, making it less likely for particles in the furnace to adhere to the surface of the wafer 201, reducing defects on the surface of the wafer 201 and improving the quality of the wafer 201.

[0054] The assembly surface 202a is at a preset angle θ to the airflow direction X of the epitaxial growth process gas so that the wafer 201 supported by the wafer holder 200 is tilted. The airflow will continuously and evenly sweep across the tilted surface of the wafer 201. The wafer 201 no longer has a fixed local area that is first impacted by the airflow, so the wafer 201 no longer has a direct windward surface, reducing defects on the surface of the wafer 201.

[0055] For example, in some embodiments of the present invention, please refer to Figure 4 When the tilted wafer 201 is placed in a high-temperature reaction furnace for epitaxial growth, the slope of the tangent of the warped wafer 201 decreases monotonically along the airflow direction X of the epitaxial growth process gas.

[0056] Furthermore, the tilt of the wafer 201 increases the contact area between the wafer 201 and the process gas, reduces the gas flow rate of the process gas, and reduces the possibility of turbulence caused by excessive gas flow rate, making the epitaxial growth process rate more uniform and the thickness uniformity of the epitaxial growth film layer higher.

[0057] During silicon carbide epitaxial growth, the flow rate of the process gas is approximately 0.1 m / s to 1 m / s. At higher flow rates, turbulence is easily generated, affecting the stability of the gas flow. By tilting the wafer 201 supported by the wafer holder 200, the cross-sectional area through which the process gas flows over the wafer 201 can be increased. According to the formula for gas flow rate, Q = VA (where Q is the operating flow rate of the gas, V is the gas velocity, and A is the effective cross-sectional area of ​​the gas flow), increasing the cross-sectional area through which the process gas flows over the wafer 201 can reduce the downstream process gas flow rate. That is, by controlling the tilt angle of the wafer 201, the flow rate of the process gas can be adjusted, thereby controlling the epitaxial growth rate, making the epitaxial growth rate more uniform, and reducing thickness inhomogeneity.

[0058] Specifically, in some embodiments of the present invention, for every 1° increase in the angle θ between the assembly surface 202a and the airflow direction X, the flow rate of the process gas can be reduced by about 10%.

[0059] Furthermore, the wafer 201 is tilted so that the temperature at the downstream end of the epitaxial growth process gas flow is slightly higher than the temperature at the upstream end, thereby compensating for the shortcoming that the effective component concentration at the downstream end of the gas flow is lower than that at the upstream end in the epitaxial growth process, making the growth rate of the wafer 201 more balanced.

[0060] Specifically, in some embodiments of the present invention, the angle between the assembly surface 202a and the gas flow direction X of the epitaxial growth process gas is in the range of 0.5° to 5°.

[0061] The angle between the assembly surface 202a and the gas flow direction X of the epitaxial growth process gas depends on the stress state of the wafer 201 and the specific growth conditions. The angle between the assembly surface 202a and the gas flow direction X of the epitaxial growth process gas is directly proportional to the stress of the wafer 201. The lower the stress of the wafer 201, the smaller the angle between the assembly surface 202a and the gas flow direction X of the epitaxial growth process gas; the higher the stress of the wafer 201, the larger the angle between the assembly surface 202a and the gas flow direction X of the epitaxial growth process gas.

[0062] The top surface of the wafer holder 200, which is located on the sidewall of the wafer holder recess, is coplanar with the assembly surface 202a. For example, ... Figure 3 and Figure 4 As shown, the top surface of the abutment part 2002 is coplanar with the assembly surface 202a.

[0063] The wafer holder 200 rotates about an axis perpendicular to the assembly surface 202a. By rotating about an axis perpendicular to the assembly surface 202a, the wafer holder 200 dynamically adjusts the relative position of the wafer 201 with the thermal field and the flow field, thereby achieving uniform epitaxial growth at various positions of the wafer 201.

[0064] Specifically, the wafer holder 200 rotates 360° around a pivot axis perpendicular to the assembly surface 202a.

[0065] The lower crescent structure 202 has high temperature resistance. Specifically, in some embodiments of the present invention, the material of the lower crescent structure 202 is graphite, and the lower crescent structure 202 is a graphite component structure.

[0066] Accordingly, this embodiment of the invention also provides an epitaxial growth apparatus, comprising: a semiconductor epitaxial growth component, the semiconductor epitaxial growth component as described in this embodiment of the invention; a reactor, the furnace cavity of the reactor being adapted to accommodate the semiconductor epitaxial growth component, the reactor including an inlet and an outlet, the direction of the inlet pointing to the outlet being the airflow direction.

[0067] Specifically, in some embodiments of the present invention, the epitaxial growth apparatus includes: a plurality of semiconductor epitaxial growth components, wherein the angle between the assembly surface of each semiconductor epitaxial growth component and the airflow direction is different.

[0068] The epitaxial growth apparatus includes multiple semiconductor epitaxial growth components, each with a different angle between its assembly surface and the airflow direction. The appropriate epitaxial growth component can be selected based on the stress state of the wafer and the specific epitaxial growth conditions.

[0069] Accordingly, embodiments of the present invention also provide an epitaxial growth process, comprising: using an epitaxial growth apparatus as described in embodiments of the present invention, and introducing reaction gas through the gas inlet of the reaction furnace.

[0070] Specifically, in some embodiments of the present invention, the reaction temperature of the epitaxial growth process is 700°C to 1600°C; the reaction gas of the epitaxial growth process includes hydrogen, ethylene, and trichlorosilane; and the flow rate of the reaction gas of the epitaxial growth process is 80 SLM to 120 SLM.

[0071] In summary, the assembly surface of the lower crescent structure is at a preset angle to the direction of the epitaxial growth process gas flow, causing the wafer supported by the wafer holder to tilt. When the wafer is placed in a high-temperature reaction furnace for epitaxial growth, due to the tilt of the wafer, the slope of the tangent of the wafer, which warps due to the high temperature along the flow direction of the process gas, changes approximately monotonically. This eliminates the direct airflow impact on the wafer's front surface, making it less likely for particles in the furnace to adhere to the wafer surface, reducing surface defects and improving wafer quality. Furthermore, the tilt of the wafer increases the contact area between the wafer and the process gas, reduces the gas flow rate, and lowers the possibility of turbulence caused by excessive gas flow, resulting in a more uniform epitaxial growth rate and higher uniformity of the epitaxial film thickness. In addition, the tilt of the wafer causes the temperature at the downstream end of the epitaxial growth process gas flow to be slightly higher than the upstream end, thus compensating for the lower effective component concentration at the downstream end of the epitaxial growth process, resulting in a more balanced wafer growth rate.

[0072] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A semiconductor epitaxial growth assembly, characterized in that, include: A wafer holder, wherein the wafer holder is adapted to support a wafer; The lower half-moon structure has an assembly surface in which the wafer holder is embedded. The assembly surface faces the process gas of epitaxial growth, and the assembly surface and the airflow direction of the process gas of epitaxial growth are at a preset angle so that the wafer supported by the wafer holder is tilted.

2. The semiconductor epitaxial growth assembly as described in claim 1, characterized in that, The angle between the assembly surface and the airflow direction of the process gas for epitaxial growth is in the range of 0.5° to 5°.

3. The semiconductor epitaxial growth assembly as described in claim 1, characterized in that, The wafer holder has a wafer holder groove facing away from the lower crescent structure; The depth of the wafer support groove is the same everywhere.

4. The semiconductor epitaxial growth assembly as described in claim 3, characterized in that, The thickness of the wafer holder at the bottom of the wafer holder groove is the same everywhere.

5. The semiconductor epitaxial growth assembly as described in claim 3, characterized in that, The top surface of the wafer holder on the sidewall of the wafer holder groove is coplanar with the assembly surface.

6. The semiconductor epitaxial growth assembly as described in claim 3, characterized in that, The depth of the wafer support groove is not less than the thickness of the wafer.

7. The semiconductor epitaxial growth assembly as described in claim 1, characterized in that, The wafer support rotates about an axis perpendicular to the assembly surface.

8. An epitaxial growth apparatus, characterized in that, include: A semiconductor epitaxial growth assembly, as described in any one of claims 1 to 7; A reactor, the furnace cavity of which is adapted to accommodate the semiconductor epitaxial growth assembly, the reactor including an inlet and an outlet, wherein the direction of the inlet pointing to the outlet is the airflow direction.

9. The epitaxial growth apparatus as described in claim 8, characterized in that, The epitaxial growth apparatus includes multiple semiconductor epitaxial growth components, each having a different angle between its assembly surface and the airflow direction.

10. An epitaxial growth process, characterized in that, include: Using the epitaxial growth apparatus as described in any one of claims 8 to 9, reaction gas is introduced through the gas inlet of the reactor.

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