Method for removing epitaxial layer, rework method and semiconductor process method

Abstract

The application relates to an epitaxial layer removal method, a rework method and a semiconductor process method. The epitaxial layer removal method comprises the following steps: providing a substrate, the substrate is provided with a metal structure and an epitaxial layer, the metal structure is located in the epitaxial layer; and removing the epitaxial layer by using a wet etching solution; under the same condition, the removal rate of the wet etching solution to the epitaxial layer is greater than the removal rate of the wet etching solution to the metal structure, and is greater than the removal rate of the wet etching solution to an oxide. The substrate is provided with a metal structure and an epitaxial layer, the metal structure is located in the epitaxial layer, the removal rate of the wet etching solution to the epitaxial layer is greater than the removal rate of the wet etching solution to the metal structure under the same condition, and the metal structure is not seriously damaged when the epitaxial layer is removed by using the wet etching solution, so that the problem that there is no good way to remove the epitaxial silicon when the epitaxial layer on the front surface of the substrate is abnormal can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, in particular to a method for removing an epitaxial layer, a rework method and a semiconductor process method. BACKGROUND

[0002] In the existing semiconductor structure, the epitaxial layer is used to isolate and protect the metal structure, which plays a crucial role in protecting the metal structure from damage.

[0003] When the epitaxial layer on the front surface of the substrate is abnormal during the back-end-of-line process, hydrofluoric acid or nitric acid is generally used to remove the epitaxial layer. However, such removal method can cause serious corrosion to the metal structure and damage the core structure of the semiconductor product. There is no better way to remove epitaxial silicon in the conventional selection. SUMMARY

[0004] Therefore, it is necessary to provide a method for removing an epitaxial layer, a rework method and a semiconductor process method to solve the problem of serious damage to the metal structure when removing the epitaxial layer.

[0005] To achieve the above-mentioned purpose, on the one hand, the present application provides a method for removing an epitaxial layer, comprising:

[0006] A substrate is provided, the substrate has a metal structure and an epitaxial layer formed thereon, and the metal structure is located in the epitaxial layer;

[0007] A wet etching solution is used to remove the epitaxial layer. Under the same conditions, the removal rate of the wet etching solution on the epitaxial layer is greater than the removal rate of the wet etching solution on the metal structure, and is greater than the removal rate of the wet etching solution on the oxide.

[0008] In one embodiment, the epitaxial layer includes a silicon epitaxial layer, and the wet etching solution includes a post-etch residue removal solution.

[0009] In one embodiment, the post-etch residue removal solution includes ethanolamine, isopropanolamine, hydroxylamine, catechol and 2-(2-aminoethoxy) ethanol.

[0010] In one embodiment, the post-etch residue removal solution further includes sulfuric acid, hydrofluoric acid, nitric acid and gallic acid.

[0011] In one embodiment, the volume percentage of sulfuric acid:hydrofluoric acid:nitric acid in the post-etch residue removal solution is 5:1:1 to 10:1:1.

[0012] In one embodiment, the etching selectivity ratio of the wet etching solution on the epitaxial layer and the metal structure is 30:1 to 50:1.

[0013] In one of the embodiments, the removing temperature is 50-90℃.

[0014] In one of the embodiments, the metal structure and the epitaxial layer are located on the front side of the substrate.

[0015] The application further provides a rework method of an epitaxial layer, comprising:

[0016] The epitaxial layer is removed by the rework method of the epitaxial layer.

[0017] An epitaxial layer is epitaxially grown on the substrate again, and the metal structure is located in the epitaxial layer grown again.

[0018] The application further provides a semiconductor process method, comprising the rework method of the epitaxial layer.

[0019] In the rework method of the epitaxial layer, the substrate is provided with a metal structure and an epitaxial layer, the metal structure is located in the epitaxial layer, under the same conditions, the removal rate of the wet etching solution to the epitaxial layer is greater than the removal rate of the wet etching solution to the metal structure, and is greater than the removal rate of the wet etching solution to the oxide, when the epitaxial layer is removed by using the wet etching solution, the wet etching solution will not cause serious damage to the metal structure and the oxide, thereby improving the problem that there is no good way to remove the epitaxial silicon when the epitaxial layer on the front side of the substrate is abnormal.

[0020] In the rework method of the epitaxial layer, the epitaxial layer is removed by the rework method of the epitaxial layer, because under the same conditions, the removal rate of the wet etching solution to the epitaxial layer is greater than the removal rate of the wet etching solution to the metal structure, and is greater than the removal rate of the wet etching solution to the oxide, when the epitaxial layer is removed by using the wet etching solution, the wet etching solution will not cause serious damage to the metal structure and the oxide, so that the metal structure will not be seriously damaged in the rework process, then an epitaxial layer is epitaxially grown on the substrate again, and the metal structure is located in the epitaxial layer grown again, thereby helping to obtain a semiconductor product with excellent structure.

[0021] The semiconductor process method of the application comprises the rework method of the epitaxial layer, and the beneficial effects thereof can refer to the technical effects of the rework method of the epitaxial layer, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0023] Figure 1 Flow chart of the method for removing the epitaxial layer provided in an embodiment;

[0024] Figure 2 Flow chart of the method for reworking the epitaxial layer provided in an embodiment;

[0025] Figure 3 Flow chart of the method for reworking the epitaxial layer provided in another embodiment. DETAILED DESCRIPTION

[0026] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the present application are shown in the accompanying drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments of the present application and are not intended to limit the present application.

[0028] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0029] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0030] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0031] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, parts, regions, layers, doping types, and / or portions, these elements, parts, regions, layers, doping types, and / or portions should not be limited by these terms.

[0032] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0033] As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It should also be understood that the term "comprising" as used in this specification, is intended to mean that the features, integers, steps, components or elements noted are present, but not excluding the addition of one or more other features, integers, steps, components, elements, or groups thereof. Similarly, the term "comprising" as used herein is also intended to include the terms "including", "has", "have", "containing", "containing", "characterized by", "comprising", "characterized" and "characterized by", and variations thereof.

[0034] In existing semiconductor structures, the epitaxial layer is used to isolate and protect the metal structure, which is crucial to protect the metal structure from damage.

[0035] When the epitaxial layer on the front surface of the substrate is abnormal during the back-end-of-line process, hydrofluoric acid or nitric acid is generally used to remove the epitaxial layer. However, such removal method can cause serious corrosion to the metal structure, damaging the core structure of the semiconductor product. There is no better way to remove epitaxial silicon in the conventional selection.

[0036] Therefore, it is necessary to provide an epitaxial layer removal method, a rework method and a semiconductor process method to solve the problem of serious damage to the metal structure during the removal of the epitaxial layer.

[0037] In order to achieve the above-mentioned purpose, as shown in the accompanying drawings, Figure 1 The present application provides an epitaxial layer removal method, comprising:

[0038] S101: providing a substrate, the substrate is formed with a metal structure and an epitaxial layer, the metal structure is located in the epitaxial layer;

[0039] S102: removing the epitaxial layer by using a wet etching solution; under the same conditions, the removal rate of the wet etching solution to the epitaxial layer is greater than the removal rate of the wet etching solution to the metal structure, and greater than the removal rate of the wet etching solution to the oxide.

[0040] Specifically, the metal structure can include but is not limited to a metal layer or a metal plug.

[0041] In the epitaxial layer removal method of the above-mentioned embodiment, the substrate is formed with a metal structure and an epitaxial layer, the metal structure is located in the epitaxial layer, under the same conditions, the removal rate of the wet etching solution to the epitaxial layer is greater than the removal rate of the wet etching solution to the metal structure, and greater than the removal rate of the wet etching solution to the oxide. When the epitaxial layer is removed by using the wet etching solution, the wet etching solution will not cause serious damage to the metal structure and the oxide, so as to improve the problem that there is no better way to remove epitaxial silicon when the epitaxial layer on the front surface of the substrate is abnormal.

[0042] In one embodiment, the epitaxial layer comprises a silicon epitaxial layer, and the wet etching solution comprises a post-etch residue removal liquid.

[0043] It should be noted that the post-etch residue removal liquid is generally used only for removing post-etch inorganic etching products such as post-etch residue removal liquid, and the post-etch residue removal liquid is used for removing silicon epitaxial layer, and will not cause damage to metal structures and organic matter.

[0044] In one embodiment, the removal rate of the wet etching solution on the epitaxial layer can be 10 to 50 times the removal rate of the wet etching solution on the metal structure; specifically, the removal rate of the wet etching solution on the epitaxial layer can be 10 times, 15 times, 20 times, 25 times, 30 times, 35 times, 40 times, 45 times or 50 times the removal rate of the wet etching solution on the metal structure, or any other removal rate within the range of 10 to 50 times, not limited by the specific examples.

[0045] Further, when the reaction temperature is 70°C, the removal rate of the wet etching solution on the epitaxial layer can be 45 to 50 times the removal rate of the wet etching solution on the metal structure, and the removal rate of the wet etching solution on the epitaxial layer can be 180 to 250 times the removal rate of the wet etching solution on the oxide; when the reaction temperature is 75°C, the removal rate of the wet etching solution on the epitaxial layer can be 10 to 15 times the removal rate of the wet etching solution on the metal structure, and the removal rate of the wet etching solution on the epitaxial layer can be 100 to 140 times the removal rate of the wet etching solution on the oxide.

[0046] In one embodiment, when the reaction temperature is set to 70°C, the removal rate of the wet etching solution on the epitaxial layer is the removal rate of the wet etching solution on the metal structure is the removal rate of the wet etching solution on the oxide is

[0047] Specifically, under the temperature condition of 70°C, the reaction rate of the wet etching solution with the epitaxial layer can be or or any other reaction rate within the range of , not limited by the specific reaction rates exemplified; the removal rate of the wet etching solution on the metal structure can be or or any other reaction rate within the range of , not limited by the specific reaction rates exemplified; the removal rate of the wet etching solution on the oxide can be or and any other reaction rate within the range of The reaction rates are not limited to the specific reaction rates exemplified.

[0048] In one embodiment, the removal rate of the wet etching solution to the metal structure is The removal rate of the wet etching solution to the metal structure is The removal rate of the wet etching solution to the metal structure is

[0049] Specifically, the reaction rate of the wet etching solution to the metal structure at a reaction temperature of 75°C can be or The reaction rates are not limited to the specific reaction rates exemplified. The removal rate of the wet etching solution to the metal structure can be or The reaction rates are not limited to the specific reaction rates exemplified. The removal rate of the wet etching solution to the metal structure can be or The reaction rates are not limited to the specific reaction rates exemplified. The reaction rates are not limited to the specific reaction rates exemplified.

[0050] In one embodiment, the post-etch residue removal solution can include ethanolamine, isopropanolamine, hydroxylamine, catechol, and 2-(2-aminoethoxy)ethanol.

[0051] The ethanolamine, isopropanolamine, hydroxylamine, catechol, and 2-(2-aminoethoxy)ethanol have very low damage to the metal structure.

[0052] In one embodiment, the post-etch residue removal solution can further include sulfuric acid, hydrofluoric acid, nitric acid, and gallic acid.

[0053] The sulfuric acid, hydrofluoric acid, nitric acid, and gallic acid, in combination with the ethanolamine, isopropanolamine, hydroxylamine, catechol, and 2-(2-aminoethoxy)ethanol, have very low removal rate to the metal structure and very high removal rate to the epitaxial layer, thus can significantly shorten the time for removing the epitaxial layer and further reduce the damage to the metal structure, and can achieve the acceleration of the etching of the epitaxial layer without damaging the metal structure.

[0054] In one embodiment, the volume percentage of sulfuric acid:hydrofluoric acid:nitric acid in the etching residue removal solution is 5:1:1-10:1:1; specifically, the volume percentage of sulfuric acid:hydrofluoric acid:nitric acid can be 5:1:1, 6:1:1, 7:1:1, 8:1:1, 9:1:1 or 10:1:1.

[0055] The proportion of the acid solution is adjusted so as to enhance the etching rate of the epitaxial layer and reduce the corrosion of the metal structure.

[0056] In one embodiment, the etching selectivity ratio of the wet etching solution to the epitaxial layer and the metal structure is 30:1-50:1.

[0057] The etching selectivity ratio of the wet etching solution to the epitaxial layer and the metal structure can be 30:1, 35:1, 40:1, 45:1 or 50:1, or any etching selectivity ratio within the range of 30:1-50:1, not limited to the specific etching selectivity ratios.

[0058] In one embodiment, the removal temperature is 50-90°C during the process of removing the epitaxial layer by using the wet etching solution.

[0059] The removal temperature can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C, or any removal temperature within the range of 50-90°C, not limited to the specific removal temperatures.

[0060] In one embodiment, the metal structure and the epitaxial layer are located on the front side of the substrate.

[0061] The application also provides a rework method of an epitaxial layer, as shown in Figure 2 The rework method of the epitaxial layer includes the following steps:

[0062] S201: removing the epitaxial layer by using the removal method of the epitaxial layer according to any one of the above embodiments;

[0063] S202: epitaxially growing an epitaxial layer on the substrate, and the metal structure is located in the epitaxially grown epitaxial layer.

[0064] That is, as shown in Figure 3 The rework method of the epitaxial layer can include the following steps:

[0065] S301: providing a substrate, the substrate is formed with a metal structure and an epitaxial layer, and the metal structure is located in the epitaxial layer;

[0066] S302: removing the epitaxial layer by using a wet etching solution; under the same conditions, the removal rate of the wet etching solution on the epitaxial layer is greater than the removal rate of the wet etching solution on the metal structure, and greater than the removal rate of the wet etching solution on the oxide.

[0067] S303: epitaxially growing an epitaxial layer on the substrate, and the metal structure is located in the epitaxially grown epitaxial layer.

[0068] The rework method of the epitaxial layer in the above embodiment removes the epitaxial layer by using the removal method of the epitaxial layer in the present application. Because the removal rate of the wet etching solution on the epitaxial layer is greater than the removal rate of the wet etching solution on the metal structure, and greater than the removal rate of the wet etching solution on the oxide under the same conditions, the wet etching solution does not cause serious damage to the metal structure and the oxide when removing the epitaxial layer by using the wet etching solution, so that the metal structure is not seriously damaged in the rework process. Then, the epitaxial layer is epitaxially grown on the substrate, and the metal structure is located in the epitaxially grown epitaxial layer, so as to help obtain a semiconductor product with excellent structure.

[0069] Specifically, the metal structure can include, but is not limited to, an aluminum layer, a copper layer, or a metal plug, and the like.

[0070] In one embodiment, the epitaxial layer includes a silicon epitaxial layer, and the wet etching solution includes a post-etch residue removal liquid.

[0071] It should be noted that the post-etch residue removal liquid is usually used only for removing the post-etch inorganic matter, such as etching products, in the front-end preparation process. The post-etch residue removal liquid is used for removing the silicon epitaxial layer, and does not cause damage to the metal structure and the organic matter.

[0072] In one embodiment, the removal rate of the wet etching solution on the epitaxial layer can be 10 times to 50 times the removal rate of the wet etching solution on the metal structure. Specifically, the removal rate of the wet etching solution on the epitaxial layer can be 10 times, 15 times, 20 times, 25 times, 30 times, 35 times, 40 times, 45 times, or 50 times the removal rate of the wet etching solution on the metal structure, or can be any removal rate multiple located between 10 times and 50 times, and is not limited by the specific examples.

[0073] Further, when the reaction temperature is 70℃, the removal rate of the wet etching solution to the epitaxial layer can be 45 to 50 times of the removal rate of the wet etching solution to the metal structure, and the removal rate of the wet etching solution to the epitaxial layer can be 180 to 250 times of the removal rate of the wet etching solution to the oxide; when the reaction temperature is 75℃, the removal rate of the wet etching solution to the epitaxial layer can be 10 to 15 times of the removal rate of the wet etching solution to the metal structure, and the removal rate of the wet etching solution to the epitaxial layer can be 100 to 140 times of the removal rate of the wet etching solution to the oxide.

[0074] In one embodiment, when the reaction temperature is set to 70℃, the removal rate of the wet etching solution to the epitaxial layer is the removal rate of the wet etching solution to the metal structure is the removal rate of the wet etching solution to the oxide is

[0075] Specifically, under the temperature condition that the reaction temperature is 70℃, the reaction rate of the wet etching solution to the epitaxial layer can be or and can also be other arbitrary reaction rates located between , which are not limited by the specific reaction rates exemplified; the removal rate of the wet etching solution to the metal structure can be or and can also be other arbitrary reaction rates located between , which are not limited by the specific reaction rates exemplified; the removal rate of the wet etching solution to the oxide can be or and can also be other arbitrary reaction rates located between , which are not limited by the specific reaction rates exemplified.

[0076] In one embodiment, when the reaction temperature is set to 75℃, the removal rate of the wet etching solution to the epitaxial layer is the removal rate of the wet etching solution to the metal structure is the removal rate of the wet etching solution to the oxide is

[0077] Specifically, under the temperature condition that the reaction temperature is 75℃, the reaction rate of the wet etching solution to the epitaxial layer can be or and can also be other arbitrary reaction rates located between , which are not limited by the specific reaction rates exemplified; the removal rate of the wet etching solution to the metal structure can be or and other arbitrary reaction rates located between The removal rate of the wet etching solution to the oxide can be or and other arbitrary reaction rates located between The removal rate of the wet etching solution to the oxide can be

[0078] In one embodiment, the post-etch residue removal solution can include ethanolamine, isopropanolamine, hydroxylamine, catechol, and 2-(2-aminoethoxy)ethanol.

[0079] The ethanolamine, isopropanolamine, hydroxylamine, catechol, and 2-(2-aminoethoxy)ethanol have very low damage to the metal structure.

[0080] In one embodiment, the post-etch residue removal solution can further include sulfuric acid, hydrofluoric acid, nitric acid, and gallic acid.

[0081] The sulfuric acid, hydrofluoric acid, nitric acid, and gallic acid, in combination with the ethanolamine, isopropanolamine, hydroxylamine, catechol, and 2-(2-aminoethoxy)ethanol, have very low removal rates to the metal structure and very high removal rates to the epitaxial layer, thus significantly shortening the time for removing the epitaxial layer and further reducing damage to the metal structure, and achieving accelerated etching of the epitaxial layer without damaging the metal structure.

[0082] In one embodiment, the volume percentage of sulfuric acid:hydrofluoric acid:nitric acid in the post-etch residue removal solution is 5:1:1 to 10:1:1. Specifically, the volume percentage of sulfuric acid:hydrofluoric acid:nitric acid can be 5:1:1, 6:1:1, 7:1:1, 8:1:1, 9:1:1, or 10:1:1.

[0083] The proportioning of the acid solutions enhances the etching rate of the epitaxial layer while reducing the etching of the metal structure.

[0084] In one embodiment, the etching selectivity ratio of the wet etching solution to the epitaxial layer and the metal structure is 30:1 to 50:1.

[0085] The etching selectivity ratio of the wet etching solution to the epitaxial layer and the metal structure can be 30:1, 35:1, 40:1, 45:1, or 50:1, or other arbitrary etching selectivity ratios located between 30:1 and 50:1, without being limited by the specific etching selectivity ratios exemplified.

[0086] In one embodiment, the removal temperature during the process of removing the epitaxial layer using the wet etching solution is 50°C to 90°C.

[0087] The removal temperature can be 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃ or 90℃, or any removal temperature between 50℃ and 90℃, not limited to the specific removal temperatures listed.

[0088] In one embodiment, the metal structure and the epitaxial layer are both located on the front side of the substrate.

[0089] The application also provides a semiconductor process method, including the rework method of the epitaxial layer as described above.

[0090] The semiconductor process method of the application can be used in the back-end-of-line process in the semiconductor manufacturing process.

[0091] The semiconductor process method of the application, including the rework method of the epitaxial layer, uses the removal method of the epitaxial layer to remove the epitaxial layer, because under the same conditions, the removal rate of the wet etching solution on the epitaxial layer is greater than the removal rate of the wet etching solution on the metal structure, and greater than the removal rate of the wet etching solution on the oxide, and when the epitaxial layer is removed by using the wet etching solution, the wet etching solution will not cause serious damage to the metal structure and the oxide, so that the metal structure will not be seriously damaged during the rework process, and then the epitaxial layer is epitaxially grown on the substrate again, and the metal structure is located in the epitaxially grown epitaxial layer to help obtain a semiconductor product with excellent structure.

[0092] It should be understood that although each step in the flowchart of each embodiment is shown in sequence according to the direction of the arrow, these steps are not necessarily executed in sequence according to the direction of the arrow. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other sequences. Moreover, at least part of the steps in each flowchart can include multiple steps or stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of these steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least part of other steps or stages.

[0093] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features of the above-described embodiments are described, but it should be considered that any combination of the technical features is within the scope of the present disclosure as long as the combination does not contradict.

[0094] The above embodiments only express several implementation ways of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation to the patent scope of the application. It should be pointed out that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method of removing an epitaxial layer, characterized by, The application relates to a method for removing an epitaxial layer. The method comprises the following steps: providing a substrate, wherein a metal structure is formed on the substrate and an epitaxial layer is formed on the substrate, and the metal structure is located in the epitaxial layer; when the epitaxial layer on the front surface of the substrate is abnormal in a back-end-of-line process, removing the epitaxial layer by using a wet etching solution; wherein the epitaxial layer comprises a silicon epitaxial layer, the wet etching solution comprises a post-etching residue removing liquid, the post-etching residue removing liquid comprises ethanolamine, isopropanolamine, hydroxylamine, catechol and 2-(2-aminoethoxy) ethanol; under the same conditions, the removal rate of the wet etching solution to the epitaxial layer is greater than the removal rate of the wet etching solution to the metal structure and greater than the removal rate of the wet etching solution to an oxide. The post-etching residue removing liquid further comprises sulfuric acid, hydrofluoric acid, nitric acid and gallic acid.

2. The method of removing epitaxial layers according to claim 1, wherein In the post-etching residue removing liquid, the volume percentage of sulfuric acid, hydrofluoric acid and nitric acid is 5:1:1-10:1:

1.

3. The method of removing epitaxial layers according to claim 2, wherein The etching selectivity ratio of the wet etching solution to the epitaxial layer and the metal structure is 30:1-50:

1.

4. The method of removing epitaxial layers according to claim 1, wherein In the process of removing the epitaxial layer by using the wet etching solution, the removal temperature is 50-90 DEG C.

5. The method of claim 1, wherein The metal structure and the epitaxial layer are located on the front surface of the substrate.

6. The method of claim 1, wherein The application further relates to a method for repairing a substrate.

7. A method of reworking an epitaxial layer, characterized by The method comprises the following steps: removing the epitaxial layer by using the method for removing an epitaxial layer according to any one of claims 1-6; and epitaxially growing an epitaxial layer on the substrate again, wherein the metal structure is located in the epitaxially grown epitaxial layer. The application further relates to a method for repairing a substrate. The method comprises the following steps: removing the epitaxial layer by using the method for removing an epitaxial layer according to any one of claims 1-6; and epitaxially growing an epitaxial layer on the substrate again, wherein the metal structure is located in the epitaxially grown epitaxial layer.

8. A semiconductor process method, characterized by, ​ ​

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