CN219689845U

CN219689845U - Airflow adjusting structure of epitaxial growth equipment

Info

Publication number: CN219689845U
Application number: CN202321268547.0U
Authority: CN
Inventors: 王华杰; 李炜; 林明献; 曹共柏; 潘帅
Original assignee: Zing Semiconductor Corp
Current assignee: Zing Semiconductor Corp
Priority date: 2023-05-23
Filing date: 2023-05-23
Publication date: 2023-09-15
Anticipated expiration: 2033-05-23

Abstract

The utility model provides an airflow regulating structure of epitaxial growth equipment, which is annular and tubular and is provided with an annular wall extending along the axial direction, wherein different positions of the annular wall are provided with different axial extending heights so as to regulate and control the airflow entering the upper part of a semiconductor substrate in the epitaxial growth process. And the local air flow above the semiconductor substrate in the epitaxial growth process is regulated by the air flow regulating structure, so that the thickness uniformity and the flatness of the epitaxial layer film are optimized. In the utility model, the air flow regulating structure and the base are two mutually independent devices, the base does not need to be regulated, the manufacturing process of the air flow regulating structure is simple, the processing period generally only needs half of the time for manufacturing the base, and the equipment cost is reduced.

Description

Airflow adjusting structure of epitaxial growth equipment

Technical Field

The utility model relates to the technical field of semiconductors, in particular to an airflow adjusting structure of epitaxial growth equipment.

Background

The epitaxial process is to grow a layer of monocrystalline silicon film on the surface of the polished semiconductor substrate by a chemical vapor deposition method, so as to realize the improvement and control of the quality and the conductivity of the surface layer of the semiconductor substrate. The surface flatness of the epitaxial layer of the semiconductor substrate is an important influencing parameter for the performance of the semiconductor device, and the better the surface flatness is, the higher the device yield and the performance are. Due to the anisotropy of monocrystalline silicon, deposition thicknesses of different areas in the film growth process are different, and therefore flatness is affected.

Disclosure of Invention

The utility model aims to provide an airflow adjusting structure of epitaxial growth equipment, which is used for solving the problem that the deposition thickness of an epitaxial layer of a semiconductor substrate is different in an epitaxial process.

In order to solve the technical problems, the utility model provides an airflow adjusting structure of epitaxial growth equipment, which is annular and tubular and is provided with an axially extending annular wall, wherein different positions of the annular wall are provided with different axial extending heights so as to adjust and control the airflow entering the upper part of a semiconductor substrate in an epitaxial growth process.

Optionally, the air flow adjustment structure has a mounting ring protruding inwardly from the annular wall.

Optionally, the mounting ring is provided with a mounting hole for connecting the airflow adjusting structure and the susceptor of the epitaxial growth apparatus, wherein the airflow adjusting structure is located at the periphery of the susceptor of the epitaxial growth apparatus.

Optionally, the material of the airflow adjusting structure comprises quartz.

Optionally, the axially extending height difference at different locations of the annular wall ranges from 200 microns to 500 microns.

Optionally, the position with the lowest axial extension height of the annular wall corresponds to the <100> crystal orientation of the semiconductor substrate, and the position with the highest axial extension height of the annular wall corresponds to the <110> crystal orientation of the semiconductor substrate.

Optionally, the position with the lowest axial extension height of the annular wall and the position with the highest axial extension height of the annular wall are arranged at intervals.

Optionally, the included angle between the positions with the lowest axial extension heights of the adjacent annular walls is 90 degrees, and the included angle between the positions with the highest axial extension heights of the adjacent annular walls is 90 degrees.

Optionally, the lowest axial extension of the annular wall is higher than or equal to the top of the susceptor of the epitaxial growth apparatus.

Optionally, the shape of the portion between the highest point and the lowest point of the annular wall is one of an arc, an elliptical arc or a sine function curve.

In the airflow adjusting structure of the epitaxial growth equipment provided by the utility model, the airflow adjusting structure is in a ring shape and is provided with the annular wall extending along the axial direction, and different positions of the annular wall are provided with different axial extending heights so as to adjust and control the airflow entering the upper part of the semiconductor substrate in the epitaxial growth process. And the local air flow above the semiconductor substrate in the epitaxial growth process is regulated by the air flow regulating structure, so that the thickness uniformity and the flatness of the epitaxial layer film are optimized. The base has higher processing and manufacturing difficulty and longer processing period, the air flow adjusting structure and the base are two mutually independent devices, the base does not need to be adjusted, the manufacturing process of the air flow adjusting structure is simple, the processing period generally only needs half of the time for manufacturing the base, and the equipment cost is reduced.

Drawings

Those of ordinary skill in the art will appreciate that the figures are provided for a better understanding of the present utility model and do not constitute any limitation on the scope of the present utility model. Wherein:

fig. 1 is a schematic crystal orientation diagram of a semiconductor substrate according to an embodiment of the present utility model.

Fig. 2 is a schematic structural view of an epitaxial growth apparatus according to an embodiment of the present utility model.

Fig. 3 is a top view of an airflow regulating structure according to an embodiment of the utility model.

Fig. 4 is a perspective view of an airflow regulating structure according to an embodiment of the utility model.

Fig. 5 is a side view of an airflow adjustment structure according to an embodiment of the utility model.

FIG. 6 is a schematic view of an embodiment of the present utility model having different axial extension at different locations of the airflow adjustment structure.

In the accompanying drawings:

10-an epitaxial growth apparatus; 11-an airflow adjustment structure; 11 a-an annular wall; 11 b-a mounting ring; 11 c-mounting holes; 11 d-the position of highest axial extension height of the annular wall; 11 e-the position of lowest axial extension height of the annular wall; 12-a base; 13-a base support arm; 14-a base support pin; 15-lifting support rods; 16-lifting shaft;

d-axially extending height differences at different positions of the annular wall;

20-semiconductor substrate.

Detailed Description

The utility model will be described in further detail with reference to the drawings and the specific embodiments thereof in order to make the objects, advantages and features of the utility model more apparent. It should be noted that the drawings are in a very simplified form and are not drawn to scale, merely for convenience and clarity in aiding in the description of embodiments of the utility model. Furthermore, the structures shown in the drawings are often part of actual structures. In particular, the drawings are shown with different emphasis instead being placed upon illustrating the various embodiments.

As used in this disclosure, the singular forms "a," "an," and "the" include plural referents, the term "or" are generally used in the sense of comprising "and/or" and the term "several" are generally used in the sense of comprising "at least one," the term "at least two" are generally used in the sense of comprising "two or more," and the term "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying any relative importance or number of features indicated. Thus, a feature defining "a first", "a second", "a third" may include either explicitly or implicitly one or at least two of such features, and the terms "mounted", "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. Furthermore, as used in this disclosure, an element disposed on another element generally only refers to a connection, coupling, cooperation or transmission between two elements, and the connection, coupling, cooperation or transmission between two elements may be direct or indirect through intermediate elements, and should not be construed as indicating or implying any spatial positional relationship between the two elements, i.e., an element may be in any orientation, such as inside, outside, above, below, or on one side, of the other element unless the context clearly indicates otherwise. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

Fig. 1 is a schematic crystal orientation diagram of a semiconductor substrate according to an embodiment of the present utility model. The inventors have found that semiconductor substrate 20 includes a <110> crystal orientation and a <100> crystal orientation, i.e., the i-th region is a <110> crystal orientation and the ii-th region is a <100> crystal orientation. Assuming that one region of <110> crystal orientation is 0 °, the <110> crystal orientation regions are also located at 90 °, 180 °, and 270 °. Whereas the <100> crystal orientation regions are located at 45 °, 135 °, 225 ° and 315 °. In the epitaxial growth process, the epitaxial layer film deposition of the I area <110> crystal orientation is thicker due to the anisotropy of the monocrystalline silicon; the epitaxial layer film deposition of the II area <100> crystal orientation is thinner, and the thickness of the epitaxial layer film deposition in different areas is different, so that the follow-up process of the semiconductor substrate is affected.

The inventors have also found that the susceptor is modified to improve the thickness uniformity and flatness of the epitaxial layer on the semiconductor substrate 20. Because the base is made of graphite, the base made of graphite has higher processing and manufacturing difficulty, and the surface layer of the base made of graphite is also required to be covered with a coating material with uniform thickness in order to prevent impurity pollution, so that the manufacturing process is complex; and the coating preparation of the base and the surface layer of the base made of graphite materials usually needs two factories to be carried out successively, and the processing period is long. Therefore, the base is modified, the cost is high, and the period is long.

The core idea of the utility model is therefore that the gas flow regulating structure is annular tubular and has an axially extending annular wall, the different positions of the annular wall having different axial extension heights for regulating the magnitude of the gas flow entering above the semiconductor substrate in the epitaxial growth process. And the local air flow above the semiconductor substrate in the epitaxial growth process is regulated by the air flow regulating structure, so that the thickness uniformity and the flatness of the epitaxial layer film are optimized. The base has higher processing and manufacturing difficulty and longer processing period, the air flow adjusting structure and the base are two mutually independent devices, the base does not need to be adjusted, the manufacturing process of the air flow adjusting structure is simple, the processing period generally only needs half of the time for manufacturing the base, and the equipment cost is reduced.

Fig. 2 is a schematic structural view of an epitaxial growth apparatus according to an embodiment of the present utility model. Fig. 3 is a top view of an airflow regulating structure according to an embodiment of the utility model. Fig. 4 is a perspective view of an airflow regulating structure according to an embodiment of the utility model. As shown in fig. 2 to 4, the present embodiment provides an airflow adjusting structure of an epitaxial growth apparatus, where the airflow adjusting structure 11 is in a ring shape and has an axially extending annular wall 11a, and different positions of the annular wall 11a have different axial extending heights to adjust and control the airflow entering the semiconductor substrate 20 during the epitaxial growth process.

With continued reference to fig. 2, the epitaxial growth apparatus 10 includes a susceptor 12, the susceptor 12 is configured to carry a semiconductor substrate 20, the airflow adjusting structure 11 is disposed on an outer periphery of the susceptor 12, a susceptor support arm 13 and a susceptor support pin 14 are further disposed below the susceptor 12, and the susceptor support arm 13 is movably connected with the susceptor support pin 14 and is configured to support the susceptor 12. The lifting support rod 15 and the lifting shaft 16 are further arranged below the base 12, the lifting support rod 15 is fixedly connected with the lifting shaft 16, and the lifting support rod 15 penetrates through the base 12. The lifting shaft 16 drives the lifting support 15 to freely lift and lower relative to the base 12 for supporting and lifting the semiconductor substrate 20. In the epitaxial growth process, the lifting support rod 15 is positioned in the through hole of the base, so that the inside of the through hole of the base is basically covered, and the epitaxial layer is prevented from growing on the back surface of the semiconductor substrate. When the epitaxial growth process is completed, the lifting support 15 is lifted up relative to the susceptor 12 to lift up the semiconductor substrate 20 so that the semiconductor substrate is moved to the next process.

The base 12 includes a circular bottom wall and a cylindrical sidewall surrounding the circular bottom wall, and the circular bottom wall and the cylindrical sidewall are made of, for example, graphite, and a uniform thickness of coating material is required on the surface of the base 12 in order to prevent contamination. In an epitaxial growth process, a semiconductor substrate 20 is placed on the circular bottom wall of the susceptor. In the epitaxial growth process, a process gas such as hydrogen dilutes a reactive gas mixed with a trace dopant formed by the source gas, flows parallel to the surface of the semiconductor substrate 20, and the supplied reactive gas is discharged to the outside of the epitaxial growth apparatus after passing over the surface of the semiconductor substrate 20 to cause epitaxial layer growth.

With continued reference to fig. 2 and 3, the air flow adjustment structure 11 has a mounting ring 11b protruding inwardly from the annular wall 11 a. The mounting ring 11b is provided with a mounting hole 11c for connecting the air flow adjusting structure 11 and the base 12. The number of the mounting holes 11c is, for example, three, and the included angle between the adjacent mounting holes 11c is, for example, 120 °, so as to ensure the stability of the air flow adjusting structure 11. The positions of the mounting holes 11c of the air flow adjusting structure 11 and the positions of the base support pins 14 are in one-to-one correspondence, and the base support pins 14 penetrate through the mounting holes 11c of the air flow adjusting structure 11 to fix the air flow adjusting structure 11 to the outside of the base 12. The mounting hole 11c of the air flow adjustment structure 11 is detachably connected to the base support pin 14 so as to replace the air flow adjustment structure 11.

Fig. 5 is a side view of an airflow adjustment structure according to an embodiment of the utility model. FIG. 6 is a schematic view of an embodiment of the present utility model having different axial extension at different locations of the airflow adjustment structure. As shown in fig. 4, the annular wall 11a has different axial extension heights at different positions, and includes a plurality of positions 11d having the highest axial extension height and a plurality of positions 11e having the lowest axial extension height. The position 11e at which the axial extension height of the annular wall is the lowest and the position 11d at which the axial extension height of the annular wall is the highest are arranged at intervals. As shown in fig. 5, the axially extending height difference d at different positions of the annular wall is, for example, in the range of 200 to 500 micrometers. As shown in fig. 4 and 6, the angle between the positions 11e with the lowest axial extension of the adjacent annular walls is 90 °, and the angle between the positions 11d with the highest axial extension of the adjacent annular walls is 90 °. The angle between the position 11e at which the axial extension of the annular wall is the lowest and the position 11d at which the axial extension of the annular wall is the highest is for example 45 °. As shown in fig. 6, the horizontal axis represents the circumferential angle of the annular wall of the airflow regulating structure in degrees, and the vertical axis represents the height of the annular wall extending axially in micrometers. Assuming that one of the positions 11d at which the circumferential wall axially extends most highly is 0 degrees, the other positions 11d at which the circumferential wall axially extends most highly are located at 90 °, 180 °, and 270 °. The lowest axial extension 11e of the annular wall is located at 45 °, 135 °, 225 ° and 315 °.

In this embodiment, the position 11e with the lowest axial extension height of the annular wall corresponds to the <100> crystal orientation of the semiconductor substrate 20, and the position 11d with the highest axial extension height of the annular wall corresponds to the <110> crystal orientation of the semiconductor substrate. The lowest axially extending position 11e of the annular wall is higher than or equal to the top of the susceptor 12, so as to avoid blocking the gas flow in the epitaxial growth process by the lowest axially extending position 11e of the annular wall. The shape of the portion between the highest position 11d and the lowest position 11e of the annular wall is, for example, one of an arc, an elliptical arc, or a sinusoidal function curve. In the epitaxial growth process, the air flow adjusting structure 11 adjusts local air flow through different axial extension heights of the annular walls, so that the thickness uniformity and the flatness of the epitaxial layer film are optimized. Specifically, the position 11d with the highest axial extension height of the annular wall blocks the air flow from passing, so that the air flow in the <110> crystal orientation of the semiconductor substrate is reduced, and further the epitaxial layer film deposition in the <110> crystal orientation of the semiconductor substrate is thinned. The position 11e with the lowest axial extension height of the annular wall enters more airflow, so that airflow in the <100> crystal orientation of the semiconductor substrate is increased, and further, the epitaxial layer film deposition of the <100> crystal orientation of the semiconductor substrate is thickened.

In this embodiment, the material of the airflow adjusting structure 11 is, for example, quartz. The manufacturing process of the quartz air flow regulating structure 11 is simple, and the processing cycle generally only needs half of the time for manufacturing the graphite base 12. The graphite base 12 has higher processing and manufacturing difficulty and complex flow; and the coating on the surface of the base 12 and the base made of graphite are usually carried out in two factories, and the processing period is long. Therefore, the airflow adjusting structures 11 with different axial extension heights are arranged on the outer sides of the bases 12, and airflow passing through the epitaxial growth process is adjusted through the airflow adjusting structures 11 with different axial extension heights, so that uniformity and flatness of film thickness of an epitaxial layer on the semiconductor substrate 20 are improved, cost is reduced, time is saved, and yield of devices is improved.

The embodiment also provides an epitaxial layer growth method, which adopts the airflow adjusting structure of the epitaxial growth equipment and comprises the following steps:

a semiconductor substrate 20 is provided, which is located on the susceptor. The semiconductor substrate 20 may be monocrystalline silicon or polycrystalline silicon, may be a semiconductor material such as silicon, germanium, silicon germanium, gallium arsenide, or a composite structure such as silicon-on-insulator. The type of semiconductor substrate 20 may be selected by those skilled in the art based on the semiconductor devices formed on the semiconductor substrate 20, and thus the type of semiconductor substrate 20 should not limit the scope of the present utility model.

A cleaning process is performed to clean the surface of the semiconductor substrate 20. The reaction gas of the cleaning process is, for example, hydrogen chloride, and the temperature of the cleaning process is, for example, 800-950 ℃; the cleaning process cleans impurities from the surface of the semiconductor substrate 20.

And performing an epitaxial growth process to form an epitaxial layer on the semiconductor substrate, wherein during the epitaxial growth process, process gas is introduced, and part of the process gas is blocked when flowing through the gas flow regulating structures with different axial extension heights so as to thin part of the epitaxial layer on the semiconductor substrate. The process gas of the epitaxial growth process is, for example, a silicon source gas, preferably, a silicon source gas such as silane. The carrier gas is, for example, hydrogen. In this embodiment, the process gas is introduced, and the process gas is highly blocked by the different axial extensions of the gas flow regulating structure 11, that is, the process gas in the <110> crystal orientation of the substrate is blocked, and the blocked process gas flows parallel to the surface of the semiconductor substrate 20, and is discharged to the outside of the epitaxial growth apparatus after forming an epitaxial layer on the surface of the semiconductor substrate 20 by using the reaction gas. The thickness uniformity and flatness of the epitaxial layer on the substrate are improved by adjusting the surface process gas flow of the semiconductor substrate 20 by the different axial extension heights of the gas flow adjustment structure 11.

In summary, in the airflow adjusting structure of the epitaxial growth apparatus provided by the embodiment of the utility model, the airflow adjusting structure is in a ring shape and has an annular wall extending along the axial direction, and different positions of the annular wall have different axial extending heights so as to adjust and control the airflow entering the upper part of the semiconductor substrate in the epitaxial growth process. And the local air flow above the semiconductor substrate in the epitaxial growth process is regulated by the air flow regulating structure, so that the thickness uniformity and the flatness of the epitaxial layer film are optimized. The base has higher processing and manufacturing difficulty and longer processing period, the air flow adjusting structure and the base are two mutually independent devices, the base does not need to be adjusted, the manufacturing process of the air flow adjusting structure is simple, the processing period generally only needs half of the time for manufacturing the base, and the equipment cost is reduced.

It should also be appreciated that while the present utility model has been disclosed in the context of a preferred embodiment, the above embodiments are not intended to limit the utility model. Many possible variations and modifications of the disclosed technology can be made by anyone skilled in the art without departing from the scope of the technology, or the technology can be modified to be equivalent. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present utility model still fall within the scope of the technical solution of the present utility model.

Claims

1. The airflow regulating structure of the epitaxial growth equipment is characterized by being annular and tubular, and having an axially extending annular wall, wherein different positions of the annular wall have different axial extension heights so as to regulate and control the airflow entering the upper part of the semiconductor substrate in the epitaxial growth process.

2. The gas flow regulating structure of an epitaxial growth apparatus of claim 1, wherein the gas flow regulating structure has a mounting ring protruding inwardly from the annular wall.

3. The airflow adjustment structure of an epitaxial growth apparatus according to claim 2, wherein the mounting ring is provided with mounting holes for connecting the airflow adjustment structure and a susceptor of the epitaxial growth apparatus, wherein the airflow adjustment structure is located at an outer periphery of the susceptor of the epitaxial growth apparatus.

4. The gas flow regulating structure of an epitaxial growth apparatus of claim 1, wherein the material of the gas flow regulating structure comprises quartz.

5. The gas flow regulating structure of an epitaxial growth apparatus of claim 1, wherein the axially extending height difference at different locations of the annular wall ranges from 200 microns to 500 microns.

6. The flow regulating structure of an epitaxial growth apparatus of claim 1, wherein the lowest axially extending position of the annular wall corresponds to the <100> crystal orientation of the semiconductor substrate and the highest axially extending position of the annular wall corresponds to the <110> crystal orientation of the semiconductor substrate.

7. The structure for adjusting the flow of epitaxial growth apparatus according to claim 6, wherein the position at which the axial extension of the annular wall is the lowest and the position at which the axial extension of the annular wall is the highest are spaced apart.

8. The structure according to claim 6, wherein an angle between positions of lowest axial extension of the adjacent annular walls is 90 °, and an angle between positions of highest axial extension of the adjacent annular walls is 90 °.

9. The flow regulating structure of an epitaxial growth apparatus according to claim 1, wherein the lowest axially extending height of the annular wall is higher than or equal to the top of the susceptor of the epitaxial growth apparatus.

10. The gas flow regulating structure of an epitaxial growth apparatus according to claim 1, wherein a shape of a portion between a position where the axial extension height of the annular wall is highest and a position where the axial extension height is lowest is one of an arc, an elliptical arc, or a sinusoidal function curve.