阅读说明：本技术 半导体结构及半导体结构的形成方法 (Semiconductor structure and method for forming semiconductor structure ) 是由 赵振阳 唐龙娟 张海洋 于 2020-05-18 设计创作，主要内容包括：一种半导体结构及半导体结构的形成方法,结构包括：衬底：位于衬底上的若干鳍部结构,若干所述鳍部结构沿平行于衬底表面方向平行排列；位于鳍部结构上的第一保护层；位于第一保护层表面的第二保护层。所述半导体结构性能得到了提升。(A semiconductor structure and a method for forming the same, the structure comprising: substrate: the fin structures are positioned on the substrate and arranged in parallel along the direction parallel to the surface of the substrate; a first protective layer on the fin structure; and the second protective layer is positioned on the surface of the first protective layer. The performance of the semiconductor structure is improved.)

1. A semiconductor structure, comprising:

substrate:

the fin structures are positioned on the substrate and arranged in parallel along the direction parallel to the surface of the substrate;

a first protective layer on the fin structure;

and the second protective layer is positioned on the surface of the first protective layer.

2. The semiconductor structure of claim 1, further comprising: the first barrier layer is positioned on the top surface and the side wall surface of the fin structure; the first protective layer is also positioned on the surface of the first barrier layer.

3. The semiconductor structure of claim 2, wherein a material of the first protective layer is the same as a material of the first barrier layer.

4. The semiconductor structure of claim 3, wherein the material of the fin structure comprises silicon germanium.

5. The semiconductor structure of claim 4, wherein the material of the first barrier layer comprises a dielectric material comprising silicon nitride.

6. The semiconductor structure of claim 3, wherein a material of the fin structure comprises silicon.

7. The semiconductor structure of claim 6, wherein the material of the first barrier layer comprises a dielectric material comprising silicon oxide.

8. The semiconductor structure of claim 2, wherein the first barrier layer has a thickness in a range of: 1.5 to 3.5 nanometers.

9. The semiconductor structure of claim 1, in which a material of the second protective layer comprises a dielectric material comprising silicon oxide.

10. The semiconductor structure of claim 1, wherein the first protective layer has a thickness in a range of: 12 to 26 nanometers; the thickness range of the second protective layer is as follows: 13 to 27 nanometers.

11. The semiconductor structure of claim 1, further comprising: and the third protective layers are positioned on the surfaces of the second protective layers.

12. The semiconductor structure of claim 11, wherein the third protective layer has a thickness in a range of: 13 to 27 nanometers.

13. The semiconductor structure of claim 11, wherein a material of the third protective layer is the same as a material of the second protective layer.

14. A method of forming a semiconductor structure, comprising:

providing a substrate;

forming a plurality of fin structures on a substrate, wherein the fin structures are arranged in parallel along a direction parallel to the surface of the substrate;

forming a first protective layer on the fin structure;

and forming a second protective layer on the surface of the first protective layer.

15. The method of forming a semiconductor structure of claim 14, wherein the method of forming a fin structure comprises: forming a plurality of initial fin part structures on a substrate, wherein the plurality of initial fin part structures are arranged in parallel along a direction parallel to the surface of the substrate; and forming a plurality of openings in the initial fin portion structure, wherein the plurality of openings penetrate through the initial fin portion structure in the arrangement direction of the initial fin portion structure to form a plurality of fin portion structures.

16. The method of forming a semiconductor structure of claim 15, wherein the method of forming the initial fin structure comprises: forming a fin material layer on a substrate; forming a patterned mask layer on the fin material layer, wherein the patterned mask layer exposes a part of the surface of the fin material layer; and etching the fin part material layer by taking the patterned mask layer as a mask until the surface of the substrate is exposed to form an initial fin part structure.

17. The method of forming a semiconductor structure of claim 16, wherein the method of forming the initial fin structure further comprises: and after the fin material layer is etched, carrying out first cleaning on the initial fin structure and the substrate.

18. The method of forming a semiconductor structure of claim 17, wherein the first cleaning process comprises a wet clean process, and the solution of the wet clean process comprises: a mixed solution of sulfuric acid solution, hydrogen peroxide solution and ammonia water.

19. The method of forming a semiconductor structure of claim 15, wherein the method of forming a fin structure comprises: forming a mask layer on the initial fin structure, wherein the mask layer exposes part of the top surface of the initial fin structure; and removing part of the initial fin structure by taking the mask layer as a mask, and forming a plurality of openings in the initial fin structure to form the fin structure.

20. The method of forming a semiconductor structure of claim 19, wherein the method of forming the fin structure further comprises: and after removing part of the initial fin part structure and before forming the first protective layer, carrying out second cleaning on the fin part structure and the substrate.

21. The method of forming a semiconductor structure of claim 20, wherein the second cleaning process comprises a wet clean process, and the solution of the wet clean process comprises: a mixed solution of sulfuric acid solution, hydrogen peroxide solution and ammonia water.

22. The method of forming a semiconductor structure of claim 15, wherein after forming the initial fin structure and before forming the fin structure, further comprising: forming a first barrier layer on the top surface and the side wall surface of the initial fin part structure; the first protective layer is also positioned on the surface of the first barrier layer.

23. The method of forming a semiconductor structure of claim 22, wherein a material of the first protective layer is the same as a material of the first barrier layer.

24. The method of forming a semiconductor structure of claim 23, wherein the fin structure material comprises silicon germanium; the material of the first barrier layer comprises a dielectric material comprising silicon nitride.

25. The method of forming a semiconductor structure of claim 24, wherein the process of forming the first barrier layer comprises an atomic layer deposition process.

26. The method of forming a semiconductor structure of claim 23, wherein a material of the fin structure comprises silicon; the material of the first barrier layer comprises a dielectric material comprising silicon oxide.

27. The method of forming a semiconductor structure of claim 26, wherein the process of forming the first barrier layer comprises an in-situ moisture generation process.

28. The method of forming a semiconductor structure of claim 22, wherein the first barrier layer has a thickness in a range of: 1.5 to 3.5 nanometers.

29. The method of forming a semiconductor structure of claim 14, wherein the first protective layer has a thickness in a range of: 12 to 26 nanometers; the thickness range of the second protective layer is as follows: 13 to 27 nanometers.

30. The method of forming a semiconductor structure of claim 14, wherein a material of the second protective layer comprises a dielectric material comprising silicon oxide.

31. The method of forming a semiconductor structure of claim 14, wherein the process of forming the first protective layer comprises an atomic layer deposition process; the process of forming the second protective layer includes an atomic layer deposition process.

32. The method of forming a semiconductor structure of claim 1, further comprising: and forming a plurality of third protective layers on the surface of the second protective layer.

33. The method of forming a semiconductor structure of claim 32, wherein the third protective layer has a thickness in a range of: 13 to 27 nanometers.

34. The method of forming a semiconductor structure according to claim 32, wherein a material of the third protective layer is the same as a material of the second protective layer.

35. The method of forming a semiconductor structure of claim 14, wherein after forming the second protective layer, further comprising: forming an isolation layer on a substrate, wherein the isolation layer is positioned on the surface of part of the side wall of the fin structure, and the top surface of the isolation layer is lower than that of the fin structure; and after the isolation layer is formed, removing the second protective layer and the first protective layer.

Technical Field

The present invention relates to the field of semiconductor manufacturing, and more particularly, to a semiconductor structure and a method for forming the same.

Background

With the continuous development of semiconductor process technology, Fin field effect transistors (Fin FETs) are widely used in the field of semiconductor manufacturing due to their excellent performance, i.e., improved circuit control, reduced leakage current, and reduced gate length.

The fin structure, as an important structure in the fin field effect transistor, has a significant impact on the performance of the fin field effect transistor.

However, as technology nodes are further reduced, the formation of fin structures has many problems.

Disclosure of Invention

The invention provides a semiconductor structure and a forming method thereof, which aims to improve the performance of the semiconductor structure.

To solve the above technical problem, an embodiment of the present invention provides a semiconductor structure, including: substrate: the fin structures are positioned on the substrate and arranged in parallel along the direction parallel to the surface of the substrate; a first protective layer on the fin structure; and the second protective layer is positioned on the surface of the first protective layer.

Optionally, the method further includes: the first barrier layer is positioned on the top surface and the side wall surface of the fin structure; the first protective layer is also positioned on the surface of the first barrier layer.

Optionally, the material of the first protection layer is the same as the material of the first barrier layer.

Optionally, the material of the fin structure includes silicon germanium.

Optionally, the material of the first barrier layer includes a dielectric material, and the dielectric material includes silicon nitride.

Optionally, the material of the fin structure includes silicon.

Optionally, the material of the first barrier layer includes a dielectric material, and the dielectric material includes silicon oxide.

Optionally, the thickness range of the first barrier layer is: 1.5 to 3.5 nanometers.

Optionally, the material of the second protection layer includes a dielectric material, and the dielectric material includes silicon oxide.

Optionally, the thickness range of the first protection layer is: 12 to 26 nanometers; the thickness range of the second protective layer is as follows: 13 to 27 nanometers.

Optionally, the method further includes: and the third protective layers are positioned on the surfaces of the second protective layers.

Optionally, the thickness range of the third protective layer is: 13 to 27 nanometers.

Optionally, the material of the third protective layer is the same as the material of the second protective layer.

Correspondingly, the technical scheme of the invention also provides a method for forming the semiconductor structure, which comprises the following steps: providing a substrate; forming a plurality of fin structures on a substrate, wherein the fin structures are arranged in parallel along a direction parallel to the surface of the substrate; forming a first protective layer on the top surface and the side wall surface of the fin structure; and forming a second protective layer on the surface of the first protective layer.

Optionally, the method for forming the fin structure includes: forming a plurality of initial fin part structures on a substrate, wherein the plurality of initial fin part structures are arranged in parallel along a direction parallel to the surface of the substrate; and forming a plurality of openings in the initial fin portion structure, wherein the plurality of openings penetrate through the initial fin portion structure in the arrangement direction of the initial fin portion structure to form a plurality of fin portion structures.

Optionally, the method for forming the initial fin structure includes: forming a fin material layer on a substrate; forming a patterned mask layer on the fin material layer, wherein the patterned mask layer exposes a part of the surface of the fin material layer; and etching the fin part material layer by taking the patterned mask layer as a mask until the surface of the substrate is exposed to form an initial fin part structure.

Optionally, the method for forming the initial fin structure further includes: and after the fin material layer is etched, carrying out first cleaning on the initial fin structure and the substrate.

Optionally, the first cleaning process includes a wet cleaning process, and a solution of the wet cleaning process includes: a mixed solution of sulfuric acid solution, hydrogen peroxide solution and ammonia water.

Optionally, the method for forming the fin structure includes: forming a mask layer on the initial fin structure, wherein the mask layer exposes part of the top surface of the initial fin structure; and removing part of the initial fin structure by taking the mask layer as a mask, and forming a plurality of openings in the initial fin structure to form the fin structure.

Optionally, the method for forming the fin structure further includes: and after removing part of the initial fin part structure and before forming the first protective layer, carrying out second cleaning on the fin part structure and the substrate.

Optionally, the second cleaning process includes a wet cleaning process, and a solution of the wet cleaning process includes: a mixed solution of sulfuric acid solution, hydrogen peroxide solution and ammonia water.

Optionally, after the forming the initial fin structure and before the forming the fin structure, further including: forming a first barrier layer on the top surface and the side wall surface of the initial fin part structure; the first protective layer is also positioned on the surface of the first barrier layer.

Optionally, the material of the fin structure includes silicon germanium; the material of the first barrier layer comprises a dielectric material comprising silicon nitride.

Optionally, the process of forming the first barrier layer includes an atomic layer deposition process.

Optionally, the material of the fin structure includes silicon; the material of the first barrier layer comprises a dielectric material comprising silicon oxide.

Optionally, the process of forming the first barrier layer includes an in-situ water vapor generation process.

Optionally, the thickness range of the first barrier layer is: 1.5 to 3.5 nanometers.

Optionally, the material of the second protection layer includes a dielectric material, and the dielectric material includes silicon oxide.

Optionally, the process for forming the first protection layer includes an atomic layer deposition process; the process of forming the second protective layer includes an atomic layer deposition process.

Optionally, the thickness range of the first protection layer is: 12 to 26 nanometers; the thickness range of the second protective layer is as follows: 13 to 27 nanometers.

Optionally, the method further includes: and forming a plurality of third protective layers on the surface of the second protective layer.

Optionally, the thickness range of the third protective layer is: 13 to 27 nanometers.

Optionally, the material of the third protective layer is the same as the material of the second protective layer.

Optionally, after forming the second protective layer, the method further includes: forming an isolation layer on a substrate, wherein the isolation layer is positioned on the surface of part of the side wall of the fin structure, and the top surface of the isolation layer is lower than that of the fin structure; and after the isolation layer is formed, removing the second protective layer and the first protective layer.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

in the semiconductor structure in the technical scheme of the invention, the fin structure is provided with the first protective layer and the second protective layer positioned on the surface of the first protective layer. The method comprises the steps of firstly forming a first protection layer, then forming a second protection layer, wherein the thickness of the first protection layer is thinner, and the thickness of the second protection layer is thinner, so that the situation that the fin structure is bent due to pressure when the thicker protection layer is formed at one time is avoided. Thereby improving the performance of the semiconductor structure.

According to the forming method of the semiconductor structure in the technical scheme, after the fin portion structure is formed, the first protective layer is formed on the top surface and the side wall surface of the fin portion structure, and the second protective layer is formed on the surface of the first protective layer. The method comprises the steps of firstly forming a first protection layer, then forming a second protection layer, wherein the thickness of the first protection layer is thinner, and the thickness of the second protection layer is thinner, so that the situation that the fin structure is bent due to pressure when the thicker protection layer is formed at one time is avoided. Thereby improving the performance of the semiconductor structure.

Furthermore, a first protective layer is formed first, then a second protective layer is formed, and the probability that the defects of the first protective layer and the defects of the second protective layer are formed at the same position is low, so that the protective effect of the first protective layer and the second protective layer on the surface of the fin structure is good, and the fin structure is prevented from being damaged by subsequent process.

Further, before the fin structure is formed, a first barrier layer is formed on the top surface and the side wall surface of the initial fin structure, the first protective layer is located on the surface of the first barrier layer, and the first barrier layer can protect the surface of the initial fin structure and avoid damage to the fin structure caused by a fin structure forming process.

Furthermore, a plurality of third protective layers are formed on the second protective layer, and the probability that the defects of the third protective layers, the defects of the first protective layer and the defects of the second protective layer are formed at the same position is lower, so that the first protective layer, the second protective layer and the third protective layer have a better protection effect on the surface of the fin structure, and the fin structure is prevented from being damaged by subsequent process procedures.

Drawings

FIG. 1 is a schematic cross-sectional view of a semiconductor structure in one embodiment;

fig. 2 to 9 are schematic cross-sectional views illustrating a semiconductor structure forming process according to an embodiment of the invention.

Detailed Description

As described in the background, the conventional fin structure formation process also has many problems. The analysis will now be described with reference to specific examples.

FIG. 1 is a cross-sectional view of a semiconductor structure according to an embodiment.

Referring to fig. 1, the semiconductor structure includes: a substrate 100; a fin structure 101 on the substrate 100; a first protection layer 102 on the top surface and the sidewall surface of the fin structure 101; and a second protective layer 103 on the surface of the first protective layer 102.

In the method for forming the semiconductor structure, an initial fin structure (not shown) is formed first, and the initial fin structure is cleaned; and removing part of the initial fin portion structure to form a fin portion structure 101, and cleaning the fin portion structure 101. In order to protect the initial fin structure, after the initial fin structure is cleaned, a first protective layer 102 is formed on the top surface and the sidewall surface of the initial fin structure. The material of the first protective layer 102 is typically silicon oxide, and the first protective layer 102 is typically formed by an in-situ water vapor generation process, so that the thickness of the first protective layer 102 is thin.

In the process of forming the fin structure 101, on one hand, when a dry etching process is adopted to remove a part of the initial fin structure 101, a part of the first protection layer 102 is also lost; on the other hand, in the cleaning process of the fin structure 101, the cleaning solution may also consume the first protection layer 102, so that the first protection layer 102 on the surface of the fin structure 101 may form defects such as holes, and the like, and thus the protection effect of the first protection layer 102 is deteriorated, and the fin structure 101 is easily damaged in the subsequent processes of forming an isolation layer and removing the first protection layer. Therefore, after the fin structure 101 is cleaned, the second protection layer 103 is formed on the surface of the first protection layer 102, so as to repair the defects on the surface of the first protection layer 102. The material of the second protection layer 103 is typically silicon oxide, and the process of forming the second protection layer 103 is typically an atomic layer deposition process.

However, the second protection layer 103 needs a certain thickness for loss in the process of forming the isolation layer, and since the width-to-height ratio of the fin structure 101 is smaller and smaller, when the thicker second protection layer 103 is formed on the top surface and the sidewall surface of the fin structure 101, the thicker second protection layer 103 generates a larger pressure on the fin structure 101, so that the fin structure 101 is easily bent, and the size accuracy of a subsequently formed device is affected, thereby affecting the performance of the semiconductor structure.

In order to solve the above problems, an embodiment of the present invention provides a semiconductor structure and a method for forming the same, in which a first protection layer is formed on a top surface and a sidewall surface of a fin structure after the fin structure is formed, and a second protection layer is formed on a surface of the first protection layer. The first protective layer and the second protective layer are thinner, so that the situation that the fin structure is bent when the thicker protective layer is formed at one time is avoided. Thereby improving the performance of the semiconductor structure.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

FIGS. 2-9 are cross-sectional structural diagrams illustrating a semiconductor structure formation process according to an embodiment of the present invention

Referring to fig. 2, a substrate 200 is provided.

The material of the substrate 200 is monocrystalline silicon.

In other embodiments, the substrate may also be a semiconductor material such as polysilicon, germanium, silicon germanium, gallium arsenide, silicon on insulator, or germanium on insulator.

Referring to fig. 3 and 4, fig. 4 is a top view of fig. 3, fig. 3 is a schematic cross-sectional view taken along a section line AA' of fig. 4, a plurality of initial fin structures 201 are formed on a substrate 200, and the plurality of initial fin structures 201 are arranged in parallel along a direction parallel to a surface of the substrate 200.

The initial fin structure 201 may be made of a semiconductor material such as silicon, germanium, silicon germanium, gallium arsenide, silicon-on-insulator, or germanium-on-insulator.

In the present embodiment, the material of the initial fin structure 201 includes silicon.

In other embodiments, the material of the initial fin structure comprises silicon germanium.

The method for forming the initial fin structure 201 includes: forming a fin material layer (not shown) on the substrate 200; forming a patterned mask layer (not shown) on the fin material layer, wherein the patterned mask layer exposes a part of the surface of the fin material layer; and etching the fin material layer by taking the patterned mask layer as a mask until the surface of the substrate 200 is exposed to form an initial fin structure 201.

The process for etching the fin material layer comprises a dry etching process.

With continued reference to fig. 3 and 4, after the fin material layer is etched, a first cleaning is performed on the initial fin structure 201 and the substrate 200.

The first cleaning can remove the reaction by-products generated by etching the fin material layer completely, and the reaction by-products are prevented from remaining on the substrate 200 and the initial fin structure 201 and affecting the performance of the subsequently formed semiconductor structure.

The first cleaning process comprises a wet cleaning process, and a solution of the wet cleaning process comprises: a mixed solution of sulfuric acid solution, hydrogen peroxide solution and ammonia water.

Referring to fig. 5, a first barrier layer 202 is formed on the top surface and the sidewall surface of the initial fin structure 201.

The first blocking layer 202 can protect the surface of the initial fin structure 201, and damage to the fin structure caused by a subsequent fin structure forming process is avoided.

The process of forming the first barrier layer 202 includes an in-situ water vapor generation process or an atomic layer deposition process. The material of the first barrier layer 202 comprises a dielectric material comprising a combination of one or more of silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, silicon carbonitride, and silicon oxycarbonitride.

In this embodiment, the material of the initial fin structure 201 includes silicon, and the process of forming the first blocking layer 202 includes an in-situ water vapor generation process; the material of the first barrier layer 202 includes silicon oxide.

The in-situ water vapor generation process can form the first barrier layer 202 which is compact in structure, thin in thickness and uniform, so that the surface of the initial fin structure 201 can be protected, and the fin structure is prevented from being damaged by a subsequent fin structure forming process.

The thickness range of the first barrier layer 202 is: 1.5 to 3.5 nanometers.

The first barrier layer 202 with the thickness range can protect the surface of the initial fin structure 201, and meanwhile, the situation that the initial fin structure 201 is stressed due to too large thickness is avoided.

In other embodiments, the material of the initial fin structure comprises silicon germanium, and the process of forming the first barrier layer comprises an atomic layer deposition process; the material of the first barrier layer comprises silicon nitride.

The material of the initial fin portion structure comprises silicon germanium, the material of the first blocking layer comprises silicon nitride, the first blocking layer can protect the surface of the initial fin portion structure, damage to the fin portion structure caused by a subsequent fin portion structure forming process is avoided, meanwhile, the silicon nitride can protect the initial fin portion structure from being oxidized in a subsequent process, and therefore performance of the initial fin portion structure is improved.

Referring to fig. 6 and 7, fig. 7 is a top view of fig. 6, fig. 6 is a schematic cross-sectional view of fig. 7 along a section line BB', a plurality of openings (not labeled) are formed in the initial fin structure 201, and the plurality of openings penetrate through the initial fin structure 201 in an arrangement direction of the initial fin structure 201 to form a plurality of fin structures 203.

The plurality of openings are used to subsequently form isolation structures within the openings, which separate the initial fin structure 201 into a plurality of electrically isolated fin structures 203.

The method for forming the fin structure 203 comprises the following steps: forming a mask layer (not shown) on the initial fin structure 201, wherein the mask layer exposes a portion of the top surface of the initial fin structure 201; and removing part of the initial fin structure 201 by taking the mask layer as a mask, and forming a plurality of openings in the initial fin structure 201 to form the fin structure 203.

The process of removing a portion of the initial fin structure 201 includes a dry etching process.

With continued reference to fig. 6 and 7, after removing a portion of the initial fin structure 201, a second cleaning of the fin structure 203 and the substrate 200 is further included.

The second cleaning process comprises a wet cleaning process, and the solution of the wet cleaning process comprises: a mixed solution of sulfuric acid solution, hydrogen peroxide solution and ammonia water.

The second cleaning can remove the reaction byproducts generated by removing a portion of the initial fin structure 201, and the reaction byproducts are prevented from remaining on the substrate 200 and the fin structure 203 and affecting the performance of the subsequently formed semiconductor structure.

In other embodiments, the first protective layer may be formed on the initial fin structure without forming an opening through the initial fin structure.

Referring to fig. 8, a first protection layer 204 is formed on the top surface and sidewall surface of the fin structure 203 and the surface of the first barrier layer 202.

The first protection layer 204 can protect the surface of the fin structure 203 and prevent the fin structure 203 from being damaged in subsequent processes.

The material of the first protective layer 204 includes a dielectric material including one or a combination of silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, silicon carbonitride, and silicon oxycarbonitride.

The material of the first protective layer 204 is the same as the material of the first barrier layer 202.

The material of the first protection layer 204 is the same as that of the first blocking layer 202, so that the defect of natural damage of the first blocking layer 202 in the process of forming the fin structure 203 can be repaired, and the fin structure 203 is prevented from being damaged in the subsequent process.

In this embodiment, the material of the first protection layer 204 includes silicon oxide.

In other embodiments, the material of the first protective layer comprises silicon nitride.

In other embodiments, the material of the first protective layer and the material of the first barrier layer can be different.

The process of forming the first protection layer 204 includes an atomic layer deposition process or a chemical vapor deposition process.

In the present embodiment, the process of forming the first protection layer 204 includes an atomic layer deposition process, which can form the first protection layer 204 with a dense structure and a thin thickness.

The thickness range of the first protection layer 204 is: 12 to 26 nanometers.

The first protection layer 204 is thinner, so that a situation that the fin structure is bent due to a large pressure on the fin structure 203 caused by too thick thickness can be avoided.

With reference to fig. 8, a second passivation layer 205 is formed on the surface of the first passivation layer 204.

The material of the second protection layer 205 comprises a dielectric material comprising one or a combination of silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, silicon carbonitride, and silicon oxycarbonitride. The process of forming the second protective layer 205 includes an atomic layer deposition process or a chemical vapor deposition process.

In this embodiment, the material of the second protective layer 205 includes silicon oxide; the process of forming the second protective layer 205 includes an atomic layer deposition process, which can form the second protective layer 205 having a dense structure and a thin thickness.

The thickness range of the second protection layer 205 is: 13 to 27 nanometers.

The second protection layer 205 in the thickness range and the first protection layer 204 can protect the fin structure 203, and meanwhile, a situation that the fin structure is bent due to pressure generated on the fin structure 203 because the thickness is too thick is avoided.

The first protection layer 204 is formed first, and then the second protection layer 205 is formed, and the probability that the defect of the first protection layer 204 and the defect of the second protection layer 205 are formed at the same position is smaller, so that the protection effect of the first protection layer 204 and the second protection layer 205 on the surface of the fin structure 203 is better, and the fin structure 203 is prevented from being damaged by the subsequent process.

The first protection layer 204 is formed first, the first protection layer 204 is thinner, the second protection layer 205 is formed, and the second protection layer 205 is thinner, so that the situation that the fin structure 203 is bent due to pressure caused by the thicker protection layer when the thicker protection layer is formed at one time is avoided. Thereby improving the performance of the semiconductor structure.

In other embodiments, further comprising: and forming a plurality of third protective layers on the surface of the second protective layer.

The thickness range of the third protective layer is as follows: 13 to 27 nanometers.

The forming process of the third protective layer comprises an atomic layer deposition process.

The material of the third protective layer is the same as the material of the second protective layer.

And forming a plurality of third protective layers on the second protective layer, wherein the probability that the defects of the third protective layers, the defects of the first protective layer and the defects of the second protective layer are formed at the same position is lower, so that the protective effect of the first protective layer, the second protective layer and the third protective layer on the surface of the fin structure is better, and the fin structure is prevented from being damaged by subsequent process procedures.

Referring to fig. 9, an isolation layer 206 is formed on a substrate 200, wherein the isolation layer 206 is located on a portion of a sidewall surface of the fin structure 203, and a top surface of the isolation layer 206 is lower than a top surface of the fin structure 203; after the isolation layer 206 is formed, the second protection layer 205, the first protection layer 204 and the first barrier layer 202 exposed by the isolation layer 206 are removed.

The method for forming the isolation layer 206 includes: forming a layer of spacer material (not shown) on the substrate 200 and on the second protective layer 204; planarizing the isolation material layer. Forming an initial isolation layer (not shown) until the top surface of the fin structure 203 is exposed; and etching back the initial isolation layer until the side wall of the fin structure 203 is exposed to form the isolation layer 206.

The material of the isolation layer 206 comprises a dielectric material comprising one or a combination of silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, silicon carbonitride, and silicon oxycarbonitride. In the present embodiment, the material of the isolation layer 206 includes silicon oxide.

In this embodiment, during the process of etching back the initial isolation layer, the second protection layer 205, the first protection layer 204, and the first blocking layer 202 on the fin structure 203 are also removed at the same time.

In other embodiments, during the etching back of the initial isolation layer, the second protection layer is removed at the same time, and the first protection layer and the first barrier layer are removed by using one or more of a dry etching process and a wet etching process.

Accordingly, an embodiment of the present invention further provides a semiconductor structure, please continue to refer to fig. 8, including: substrate 200: a plurality of fin structures 203 located on the substrate 200, the plurality of fin structures 203 being arranged in parallel along a direction parallel to the surface of the substrate 200; a first protection layer 204 on the fin structure 203; and a second protective layer 205 on the surface of the first protective layer 204.

In this embodiment, the thickness range of the first protection layer 204 is: 12 to 26 nanometers; the thickness range of the second protection layer 205 is: 13 to 27 nanometers.

In this embodiment, the method further includes: a first barrier layer 202 on a top surface and sidewall surfaces of the fin structure 203; the first protective layer 204 is also located on the surface of the first barrier layer 202.

In this embodiment, the material of the first protection layer 204 is the same as the material of the first barrier layer 202.

In the present embodiment, the material of the fin structure 203 includes silicon germanium.

In the present embodiment, the material of the first barrier layer 202 includes a dielectric material, and the dielectric material includes silicon nitride.

In other embodiments, the material of the fin structure comprises silicon.

In other embodiments, the material of the first barrier layer comprises a dielectric material comprising silicon oxide.

In this embodiment, the thickness range of the first barrier layer 202 is: 1.5 to 3.5 nanometers.

In this embodiment, the material of the second protection layer 205 includes a dielectric material, and the dielectric material includes silicon oxide.

In other embodiments, further comprising: and the third protective layers are positioned on the surfaces of the second protective layers.

In other embodiments, the thickness of the third protective layer ranges from: 13 to 27 nanometers.

In other embodiments, the material of the third protective layer is the same as the material of the second protective layer.

The fin structure 203 of the semiconductor structure has a first protection layer 204 thereon, and a second protection layer 205 on a surface of the first protection layer 204. The first protection layer 204 is formed first, the first protection layer 204 is thinner, the second protection layer 205 is formed, and the second protection layer 205 is thinner, so that the situation that the fin structure 203 is bent due to pressure generated by the thicker protection layer when the thicker protection layer is formed at one time is avoided. Thereby improving the performance of the semiconductor structure.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.