Semiconductor structure and forming method thereof
By forming side walls in the substrate to prevent substrate crystal growth and forming epitaxial layers on the substrate, the problem of alignment mark drift or distortion after epitaxial growth is solved, and the electrical performance of semiconductor devices is improved.
Patent Information
- Application Number
- CN202411993930.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-05-06
AI Technical Summary
In silicon epitaxial process, the alignment marks often drift or distort after epitaxial growth, resulting in blurred pattern edges, affecting subsequent process and electrical characteristics of semiconductor devices.
A first opening is formed in the substrate and a side wall is formed on its side walls, and the material of the side walls is able to prevent the growth of substrate crystals. Then, an epitaxial layer is formed in the first opening and on the substrate, with a second opening corresponding to the first opening in the epitaxial layer.
Through the protection of the side wall, the epitaxial layer is ensured to grow at the same rate in all directions, avoid pattern drift or distortion, improve the sharpness of the pattern edges of the epitaxial layer, and ensure the alignment accuracy of subsequent lithography processes and the electrical performance of semiconductor devices.
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Figure CN119943653A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a semiconductor structure and a forming method thereof. Background Art
[0002] In the semiconductor manufacturing process, multiple layers of regionally selective processes are usually performed on a substrate, and the patterns of each layer of the process need to be aligned. Silicon epitaxy is one of the commonly used processes. In silicon epitaxy, a silicon wafer is used as a seed crystal, and a thin layer of silicon is grown on the surface of the silicon wafer to form a silicon epitaxial layer. The silicon epitaxial layer will replicate the crystal structure of the silicon wafer and have the same lattice arrangement as the silicon wafer. In the prior art, before silicon epitaxy is performed, a recessed pattern, i.e., an alignment mark, is etched on the silicon substrate before the epitaxial layer is grown. After epitaxial growth, the alignment mark often drifts or distorts, and the edge of the pattern is no longer sharp and becomes blurred, making it impossible to align the photolithography, resulting in errors in the subsequent process, thereby affecting the electrical properties of the semiconductor device finally formed.
[0003] Therefore, how to avoid deformation of alignment marks after epitaxial growth is a problem that needs to be solved urgently. Summary of the invention
[0004] The technical problem solved by the present invention is to provide a semiconductor structure and a method for forming the same, so as to solve the problem of deformation of alignment marks after epitaxial growth.
[0005] In order to solve the above technical problems, the technical solution of the present invention provides a method for forming a semiconductor structure, including: forming a first opening in a substrate; forming a side wall on the side wall of the first opening, the material of the side wall can block the growth of substrate crystals on the side wall of the first opening; after forming the side wall, forming an epitaxial layer in the first opening and on the substrate, the epitaxial layer having a second opening corresponding to the first opening.
[0006] Optionally, the method for forming the side wall includes: forming a first material film on the surface of the substrate, and the side walls and bottom surface of the first opening; forming a second material film on the surface of the first material film, and the second material film can block the crystal growth of the first material film and the substrate; etching the second material film using a patternless etching process until the first material film located on the surface of the substrate and the bottom surface of the first opening is exposed to form a second side wall layer; removing the exposed first material film to form a first side wall layer between the side wall of the first opening and the second side wall layer.
[0007] Optionally, the substrate is a silicon substrate, the material of the first material film is silicon dioxide, and the material of the second material film is silicon nitride.
[0008] Optionally, the thickness of the first material film ranges from 100 angstroms to 130 angstroms.
[0009] Optionally, the thickness of the second material film ranges from 400 angstroms to 700 angstroms.
[0010] Optionally, a width of the first opening ranges from 1.5 microns to 4 microns, and a depth of the first opening is 0.75 microns.
[0011] Optionally, the material of the epitaxial layer is the same as that of the substrate.
[0012] Optionally, the method for forming the side wall includes: forming a second material film on the surface of the substrate, and the side walls and bottom surface of the first opening; using a patternless etching process to etch the second material film located on the surface of the substrate and the bottom surface of the first opening until the surface of the substrate and the bottom surface of the first opening are exposed to form the side wall.
[0013] Correspondingly, the technical solution of the present invention also provides a semiconductor structure formed by the above-mentioned formation method, including: a substrate, having a first opening therein; a side wall, located on the side wall of the first opening, and the material of the side wall can block the growth of substrate crystals on the side wall of the first opening; an epitaxial layer, located in the first opening and on the substrate, having the side wall between the epitaxial layer and the side wall surface of the first opening, and having a second opening corresponding to the first opening therein.
[0014] Optionally, the pattern of the second opening is further determined based on the pattern of the first opening and the side wall.
[0015] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:
[0016] In the semiconductor structure and the method for forming the same provided by the technical solution of the present invention, after the sidewalls are formed on the sidewalls of the first opening in the substrate, an epitaxial layer is formed in the first opening and on the substrate, and the material of the sidewalls can block the growth of the substrate crystals on the sidewalls of the first opening. Therefore, in the process of forming the epitaxial layer, the sidewalls of the first opening are shielded and protected by the sidewalls, and the epitaxial process only uses the substrate surface and the bottom surface of the first opening with the same crystal orientation as the seed crystals for material growth, so that the epitaxial growth rates at various locations are similar or the same, so that the pattern edge of the second opening in the epitaxial layer is sharp, and the problem of pattern deformation of the second opening is improved. Therefore, when the second opening is used as an alignment mark for a subsequent photolithography process, the alignment of the subsequent photolithography process is more accurate and the deviation is smaller, which ensures the normal progress of the subsequent process, thereby ensuring the electrical performance of the semiconductor device finally formed. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 and Figure 2It is a schematic structural diagram of each step in a method for forming a semiconductor structure;
[0018] Figures 3 to 7 It is a structural schematic diagram of each step in the method for forming a semiconductor structure according to an embodiment of the present invention.
[0019] Reference numerals:
[0020] 100, 200 - silicon substrate; 110, 400 - epitaxial layer; 101, 111 - opening; 210 - first opening; 300 - side wall; 310 - first material film; 311 - first side wall layer; 320 - second material film; 321 - second side wall layer; 410 - second opening. DETAILED DESCRIPTION
[0021] As described in the background art, after epitaxial growth, alignment marks often drift or become distorted, which affects subsequent process steps and thus the performance of semiconductor devices.
[0022] Figure 1 and Figure 2 The present invention is a structural schematic diagram of each step in a method for forming a semiconductor structure.
[0023] Please refer to Figure 1 , the substrate 100 is etched to form an opening 101 in the substrate 100 .
[0024] The substrate 100 may be a silicon substrate.
[0025] Please refer to Figure 2 , an epitaxial growth process is performed on the surface of the substrate 100 where the opening 101 is exposed, to form an epitaxial layer 110. Since the epitaxial growth process is performed on the surface of the substrate 100 where the opening 101 is exposed, the pattern of the opening 101 is transferred to the epitaxial layer 110, and an opening 111 corresponding to the opening 101 is formed in the epitaxial layer 110. The opening 111 serves as an alignment mark for a subsequent photolithography process.
[0026] However, since the crystal orientation of the surface of the substrate 100 and the bottom of the opening 101 is different from that of the side walls of the opening 101, and the epitaxial growth rates at different crystal orientations are different, the pattern of the opening 111 drifts or is distorted relative to the exposed opening 101, and the edge of the pattern is blurred and no longer sharp, making it difficult to align the subsequent photolithography process, affecting the normal progress of other subsequent process steps, and causing the final semiconductor device to have poor performance.
[0027] In order to solve the above technical problems, the technical solution of the present invention provides a semiconductor structure and a method for forming the same. After forming a side wall on the side wall of the first opening that can block the growth of the substrate crystal on the side wall of the first opening, an epitaxial layer is formed in the first opening and on the substrate, so that the edge of the pattern of the second opening in the epitaxial layer is sharp, and the pattern deformation problems such as drift or distortion of the second opening are improved, thereby improving the performance of the semiconductor structure.
[0028] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.
[0029] Figures 3 to 7 It is a structural schematic diagram of each step in the method for forming a semiconductor structure according to an embodiment of the present invention.
[0030] Step S0: Please refer to Figure 3 , providing a substrate 200. Optionally, the substrate 200 is a silicon substrate.
[0031] Step S1: etching the substrate 200 to form a first opening 210 in the substrate 200. Figure 3 shown.
[0032] Specifically, the method of etching the substrate 200 to form the first opening 210 includes: forming a photolithography pattern layer on the surface of the substrate 200; etching the substrate 200 with the photolithography pattern layer as a mask to form the first opening 210 in the substrate 200; and removing the photolithography pattern layer. The process of etching the substrate 200 may adopt a dry etching process or a wet etching process. The specific etching process may adopt conventional technical means in the art, which will not be described in detail herein.
[0033] Preferably, the width of the first opening 210 is in a range of 1.5 micrometers to 4 micrometers, and the depth of the first opening 210 is 0.75 micrometers.
[0034] Step S2 : forming a sidewall spacer 300 on the sidewall of the first opening 210 . The material of the sidewall spacer 300 can block the growth of crystals of the substrate 200 on the sidewall of the first opening 210 .
[0035] In the subsequent formation of the epitaxial layer 400 (eg Figure 7As shown in , since the side wall 300 that can block the crystal growth of the substrate 200 is formed on the side wall of the first opening 210, the epitaxial growth process only grows at the same epitaxial growth rate on the surface of the substrate 200 and the bottom surface of the first opening 210 with the same crystal orientation to form the epitaxial layer 400, thereby avoiding the problem of drift or distortion of the first opening pattern caused by the epitaxial layer material growing at different epitaxial growth rates on the side wall of the first opening 210 with different crystal orientations from the surface of the substrate 200 and the bottom surface of the first opening 210 in the prior art epitaxial growth process, thereby avoiding the problem of difficulty in alignment in the subsequent photolithography process, ensuring the normal progress of other subsequent processes, and further ensuring the normal performance of the semiconductor device.
[0036] In one embodiment, the spacer 300 includes a first spacer layer 311 and a second spacer layer 321. Figures 4 to 6 A method of forming the sidewall spacer 300 will be described in detail.
[0037] Step S211: Please refer to Figure 4 , a first material film 310 is formed on the surface of the substrate 200 and the sidewalls and bottom surface of the first opening 210 .
[0038] The first material film 310 provides material for forming a first spacer layer 311 .
[0039] The material of the first material film 310 is different from the material of the substrate 200. Optionally, the material of the first material film 310 is silicon dioxide.
[0040] In one implementation, the surface of the substrate 200 where the first opening 210 is exposed may be grown by a furnace to form the first material film 310 .
[0041] Specifically, the substrate 200 is placed in a furnace tube, and high-purity oxygen is introduced at a high temperature of 600° C. to 1100° C. to grow a layer of silicon dioxide film on the surface of the substrate 200. The temperature and the purity of oxygen can be set accordingly according to the required thickness of the silicon dioxide film, and are not limited here.
[0042] The first material film 310 may also be formed by a chemical vapor deposition process. Those skilled in the art may select a suitable process according to specific circumstances, which is not limited here.
[0043] The first material film 310 may have a thickness ranging from 100 angstroms to 130 angstroms.
[0044] Preferably, according to the semiconductor structure requirements of different products, the thickness of the first material film 310 can be 100 angstroms, 110 angstroms, 120 angstroms or 130 angstroms, etc.
[0045] Step S212: Please continue to refer to Figure 4, a second material film 320 is formed on the surface of the first material film 310 .
[0046] The second material film 320 provides material for forming the second spacer layer 321 .
[0047] The material of the second material film 320 is different from that of the first material film 310 , and the material of the second material film 320 is also different from that of the substrate 200 . The second material film 320 can prevent the crystal growth of the substrate 200 on the side wall of the first opening 210 , thereby achieving that the material of the side wall 300 can block the growth of crystals of the substrate 200 on the side wall of the first opening 210 .
[0048] The second material film 320 can not only block the growth of the crystal of the substrate 200 on the side wall of the first opening 210, but also block the material of the first material film 310 from growing on the surface of the second material film 320 itself. Therefore, when the material of the first material film 310 is a material other than the substrate material, such as silicon dioxide, which will also grow during the epitaxial growth process, the second material film 320 can better ensure that the epitaxial layer material is subsequently grown only on the surface of the substrate 200 with the same crystal orientation and the bottom surface of the first opening 210 at the same epitaxial growth rate, forming a second opening 410 with precise size and position to serve as an alignment mark in subsequent photolithography.
[0049] Specifically, the material of the second material film 320 may be a non-single crystal material, and preferably, the second material film 320 may be silicon nitride. Silicon nitride has the characteristics of high temperature resistance, strong oxidation resistance, low thermal expansion coefficient, good thermal stability, etc., and is a good protective layer. When performing the epitaxial growth process, since the second sidewall layer 321 using silicon nitride as the sidewall 300 can prevent the crystal of the substrate 200 on the sidewall of the first opening 210 from growing epitaxially, the first opening 210 can avoid distortion during the epitaxial growth process, so that the edge of the second opening 410 formed after the subsequent epitaxial growth is sharp and clear, and the position does not drift relative to the first opening 210. Therefore, the second opening 410, as an alignment pattern for the subsequent photolithography process, can improve the accuracy of photolithography and ensure the normal progress of other subsequent processes.
[0050] Moreover, since the material of the second material film 320 is different from that of the first material film 310, on the one hand, in the subsequent etching process of etching the second material film 320 to form the second sidewall layer 321, the etching process can have different etching rates for different materials, so that the first material film 310 can be used as an etching stop layer to stop etching and protect the substrate 200; on the other hand, the second sidewall layer 321 formed based on the second material film 320 can be retained in the subsequent wet etching process of forming the first sidewall layer 311, and used as a mask layer for forming the first sidewall layer 311. In this way, a sidewall 300 of a composite structure composed of the first sidewall layer 311 and the second sidewall layer 321 is formed.
[0051] In addition, when the material of the second material film 320 is silicon nitride, the first material film 310 can act as a buffer film to effectively buffer the excessive stress generated by the silicon nitride film on the substrate 200, thereby avoiding damage to the substrate 200 or deformation of the substrate 200. In particular, when the material of the first material film 310 is silicon dioxide, the first material film 310 not only realizes the function of stopping etching and protecting the substrate 200, but also serves as a good stress buffer layer.
[0052] The process of forming the second material film 320 may adopt a deposition process.
[0053] Optionally, the thickness of the second material film 320 is greater than that of the first material film 310. Therefore, on the one hand, the difficulty of forming the second material film 320 is reduced, and on the other hand, the second spacer 321 is ensured to be retained during and after the subsequent removal of the exposed first material film 310.
[0054] Furthermore, the thickness of the second material film 320 is in a range of 400 angstroms to 700 angstroms.
[0055] Preferably, according to the semiconductor structure requirements of different products, the thickness of the second material film 320 can be 400 angstroms, 500 angstroms, 600 angstroms or 700 angstroms, etc.
[0056] Step S213: Please refer to Figure 5 The second material film 320 is etched by a blanket etching process until the first material film 310 located on the surface of the substrate 200 and the bottom surface of the first opening 210 is exposed, thereby forming a second spacer layer 321 .
[0057] By etching the second material film 320 using a patternless etching process, specifically, the second material film 320 can be etched using a dry etching process, and more specifically, the second material film 320 can be etched using an anisotropic etching process, so that the second material film 320 in the horizontal direction (i.e., the second material film 320 on the surface of the substrate 200 and the bottom surface of the first opening 210) has a higher etching rate, while the second material film 320 in the vertical direction is not etched or has a very low etching rate. Thus, the second spacer layer 321 is formed without a mask.
[0058] Furthermore, the etching process for etching the second material film 320 is a plasma etching process.
[0059] Step S214: Please refer to Figure 6 After the second spacer layer 321 is formed, a wet etching process is used to remove the exposed first material film 310 , and a first spacer layer 311 is formed between the sidewall of the first opening 210 and the second spacer layer 321 .
[0060] The first spacer layer 311 and the second spacer layer 321 form a composite structure of the spacer 300 , which can block the growth of the substrate 200 crystals on the sidewall of the first opening 210 , wherein the first spacer layer 311 is located between the sidewall of the first opening 210 and the second spacer layer 321 .
[0061] In one implementation, a wet etching process is used to remove the exposed first material film 310 .
[0062] Specifically, when the material of the first material film 310 is silicon dioxide, the acid solution used in the wet etching process is hydrofluoric acid. In this step, hydrofluoric acid will only remove the first material film 310 and will not remove the second material film 320. Therefore, after wet etching, a composite structure side wall 300 is formed on the side wall of the first opening 210.
[0063] Different from the sidewall 300 of the composite structure in the above-mentioned embodiment, in another embodiment, the sidewall does not include the first sidewall layer 311, but is directly composed of the second sidewall layer 321. Specifically, the method for forming the sidewall includes: forming a second material film 320 on the surface of the substrate 200, and the sidewall and bottom surface of the first opening 210; etching the second material film 320 located on the surface of the substrate 200 and the bottom surface of the first opening 210 by a patternless etching process until the surface of the substrate 200 and the bottom surface of the first opening 210 are exposed, forming a second sidewall layer 321, and the second sidewall layer 321 is a sidewall. Specifically, the second material film 320 can be etched by a dry etching process. More specifically, the second material film 320 can be etched by an anisotropic etching process. Compared with the sidewall 300 of the composite structure, in this embodiment, the growth of the substrate 200 crystal on the sidewall of the first opening 210 can be blocked by the sidewall, while reducing the process steps, thereby improving production efficiency and saving production costs.
[0064] Step S3: Please refer to Figure 7 After the spacer 300 is formed, an epitaxial layer 400 is formed in the first opening 210 and on the substrate 200 , and the epitaxial layer 400 has a second opening 410 corresponding to the first opening 210 .
[0065] In one embodiment, an epitaxial layer 400 is formed in the first opening 210 and on the substrate 200, and the material of the epitaxial layer 400 is the same as that of the substrate 200. As an example, the substrate 200 may be a silicon substrate, and an epitaxial layer 400 of the same material as that of the silicon substrate is formed in the first opening 210 and on the substrate 200 by homoepitaxial growth. Specifically, silicon is reduced on the silicon substrate by chemical vapor deposition using silicon sources SiH4, SiH2Cl2, SiHCl3 and SiCl4 and the like to react with hydrogen, such as: SiCl4+2H2→Si+4HCl. The epitaxial process is a common technical means in the art, which will not be described in detail here. Those skilled in the art may select appropriate processes and process conditions according to specific circumstances, which are not limited here.
[0066] Specifically, the second opening 410 is used as an alignment mark for the subsequent photolithography process and is used for alignment in the subsequent photolithography process. After steps S1-S3, the second opening 410 in the semiconductor structure is aligned with the first opening 210, avoiding the problem of the second opening 410 pattern drifting or distortion relative to the first opening 210, thereby achieving the alignment of the subsequent photolithography process, ensuring the normal progress of other subsequent process steps, and further ensuring the normal performance of the semiconductor device.
[0067] After the sidewall 300 is formed on the sidewall of the first opening 210 in the substrate 200, the epitaxial layer 400 is formed in the first opening 210 and on the substrate 200, and the material of the sidewall 300 is different from that of the substrate 200. Therefore, in the process of forming the epitaxial layer 400, the sidewall of the first opening 210 is shielded and protected by the sidewall 300, and the epitaxial process only uses the surface of the substrate 200 with the same crystal orientation and the bottom surface of the first opening 210 as the seed crystal for material growth, so that the epitaxial growth rate at each location is similar or the same, so that the pattern edge of the second opening 410 in the epitaxial layer 400 is sharp, and the pattern deformation problem of the second opening 410 is improved. As a result, the performance of the semiconductor structure is improved. In particular, when the second opening 410 is used as an alignment mark for a subsequent photolithography process, the pattern edge of the second opening 410 in the epitaxial layer 400 is sharp, and the pattern deformation problem of the second opening 410 is improved. Therefore, the alignment of the subsequent photolithography process is more accurate and the deviation is smaller, thereby being able to well improve the electrical performance of the semiconductor structure.
[0068] Further, the pattern of the second opening 410 is determined based on the pattern of the first opening 210 and the sidewall 300. That is, the pattern of the second opening 410 is defined by transferring the pattern of the bottom surface of the first opening 210 and the opening structure formed by the sidewall 300. Specifically, the opening structure is formed by the sidewall surface of the sidewall 300 and the bottom surface of the first opening 210, and the width of the second opening 410 is consistent with the width of the opening structure.
[0069] It should be understood that a side wall 300 of suitable thickness can be formed by the first material film 310 and the second material film 320 within the aforementioned thickness range, that is, the thickness of the side wall 300 is much smaller than the width of the first opening 210 , and therefore, the effect of the thickness of the side wall 300 on the size of the second opening 410 is almost negligible.
[0070] Please continue to refer to Figure 7 An embodiment of the present invention further provides a semiconductor structure formed by the above-mentioned formation method, comprising: a substrate 200, a spacer 300 and an epitaxial layer 400.
[0071] The substrate 200 has a first opening 210 therein.
[0072] The sidewall spacer 300 is located on the sidewall of the first opening 210 , and the material of the sidewall spacer 300 can block the growth of crystals of the substrate 200 on the sidewall of the first opening 210 .
[0073] In one embodiment, the spacer 300 includes a first spacer layer 311 and a second spacer layer 321 . The first spacer layer 311 is located between the sidewall of the first opening 210 and the second spacer layer 321 .
[0074] In another embodiment, there is no first spacer layer 311 between the second spacer layer 321 and the sidewall of the first opening 210 , that is, the second spacer layer 321 serves as a sidewall.
[0075] Furthermore, the pattern of the second opening 410 is determined based on the pattern of the first opening 210 and the sidewall 300. That is, the pattern of the second opening 410 is defined by transferring the pattern of the opening structure formed by the bottom surface of the first opening 210 and the sidewall 300.
[0076] Since the semiconductor structure of the above embodiment is formed based on the method for forming the semiconductor structure, for detailed description of each feature of the semiconductor structure of the above embodiment, please refer to the relevant explanations and descriptions in the method for forming the semiconductor structure, which will not be repeated here.
[0077] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.
Claims
1. A method for forming a semiconductor structure, characterized in that: include: forming a first opening in a substrate; forming a sidewall on the sidewall of the first opening, wherein the material of the sidewall can block the growth of substrate crystals on the sidewall of the first opening; After the sidewall spacer is formed, an epitaxial layer is formed in the first opening and on the substrate, wherein the epitaxial layer has a second opening corresponding to the first opening.
2. The method for forming a semiconductor structure according to claim 1, wherein: The method for forming the side wall includes: forming a first material film on the surface of the substrate and the sidewalls and bottom surface of the first opening; forming a second material film on the surface of the first material film, wherein the second material film can block the growth of crystals of the first material film and the substrate; Etching the second material film by a patternless etching process until the first material film located on the surface of the substrate and the bottom surface of the first opening is exposed to form a second sidewall layer; The exposed first material film is removed, and a first spacer layer is formed between the sidewall of the first opening and the second spacer layer.
3. The method for forming a semiconductor structure according to claim 2, wherein: The substrate is a silicon substrate, the material of the first material film is silicon dioxide, and the material of the second material film is silicon nitride.
4. The method for forming a semiconductor structure according to claim 3, characterized in that: The thickness of the first material film is in a range of 100 angstroms to 130 angstroms.
5. The method for forming a semiconductor structure according to claim 4, characterized in that: The thickness of the second material film is in a range of 400 angstroms to 700 angstroms.
6. The method for forming a semiconductor structure according to claim 1, wherein: The width of the first opening is in a range of 1.5 micrometers to 4 micrometers, and the depth of the first opening is 0.75 micrometers.
7. The method for forming a semiconductor structure according to claim 1, wherein: The material of the epitaxial layer is the same as that of the substrate.
8. The method for forming a semiconductor structure according to claim 1, wherein: The method for forming the side wall includes: forming a second material film on the surface of the substrate, and the sidewalls and bottom surface of the first opening; The second material film located on the substrate surface and the bottom surface of the first opening is etched by a patternless etching process until the substrate surface and the bottom surface of the first opening are exposed to form the sidewall.
9. A semiconductor structure, characterized in that: A semiconductor structure formed by the method for forming a semiconductor structure according to any one of claims 1 to 7, wherein the semiconductor structure comprises: A substrate having a first opening therein; A sidewall, located on a sidewall of the first opening, wherein a material of the sidewall can block the growth of substrate crystals on the sidewall of the first opening; An epitaxial layer is located in the first opening and on the substrate, the sidewall is provided between the epitaxial layer and the sidewall surface of the first opening, and a second opening corresponding to the first opening is provided in the epitaxial layer.
10. The semiconductor structure according to claim 9, characterized in that: The pattern of the second openings is further determined based on the pattern of the first openings and the sidewalls.