Manufacturing method of semiconductor device

Abstract

The invention provides a manufacturing method of a semiconductor device, which comprises the following steps of: performing photoetching treatment on a photoresist layer to form an opening in the photoresist layer; then, a mask layer is formed, the opening is filled with the mask layer, the mask layer extends to cover the top surface of the photoresist layer, the photosensitive wave band of the mask layer is different from that of the photoresist layer, or the material of the mask layer is different from that of the photoresist layer; then, the mask layer and the photoresist layer are heated, so that the contact surfaces of the mask layer and the photoresist layer are fused to form a protective layer, and the protective layer covers the side wall of the opening and the top surface of the photoresist layer; thirdly, removing the mask layer to expose the bottom of the opening; afterwards, the line width of the bottom of the opening is measured. As the protective layer covers the side wall of the opening and the top surface of the photoresist layer, when the line width of the bottom of the opening is measured, the protective layer can effectively prevent the outline of the photoresist layer from changing, so that the outline of the opening in the photoresist layer is prevented from changing, and the line width of the opening is further prevented from changing.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for manufacturing a semiconductor device. Background Art

[0002] In the manufacturing process of semiconductor devices, the photolithography process is one of the most important process steps for making integrated circuits. The photolithography process is used to form a desired pattern on a substrate. With the development of integrated circuit technology and the continuous reduction of the critical dimension of semiconductor components, the requirements for the accuracy of the photolithography process are getting higher and higher. Therefore, after the photoresist layer is photolithographically processed, the line width of the opening formed in the photoresist layer is measured. However, when measuring the line width of the opening, if the photoresist layer is sensitive to the electron beam emitted by the measuring device, the boundary of the exposure area of ​​the photoresist layer will be expanded outward, thereby causing the profile of the opening in the photoresist layer to change, that is, the line width of the opening will be increased, which will cause the measured data to be larger than the actual line width, and the line width of the opening in the photoresist layer cannot be accurately obtained. Summary of the invention

[0003] The object of the present invention is to provide a method for manufacturing a semiconductor device, which can avoid the problem of opening line width variation caused by changes in the profile of the photoresist layer when measuring the line width of the opening in the photoresist layer.

[0004] To achieve the above object, the present invention provides a method for manufacturing a semiconductor device, comprising:

[0005] Providing a substrate, on which a photoresist layer is formed, and the photoresist layer covers the substrate;

[0006] Performing photolithography on the photoresist layer to form an opening in the photoresist layer;

[0007] forming a mask layer, wherein the mask layer fills the opening and extends to cover the top surface of the photoresist layer, the photosensitive band of the mask layer is different from the photosensitive band of the photoresist layer, or the material of the mask layer is different from the material of the photoresist layer;

[0008] Heat-treating the mask layer and the photoresist layer so that the contact surfaces of the mask layer and the photoresist layer are fused to form a protective layer, wherein the protective layer covers the sidewalls of the opening and the top surface of the photoresist layer;

[0009] removing the mask layer to expose the bottom of the opening;

[0010] Measure the line width at the bottom of the opening.

[0011] Optionally, in the method for manufacturing the semiconductor device, the temperature of the heating treatment is 90°C to 130°C.

[0012] Optionally, in the method for manufacturing a semiconductor device, the photoresist layer is an electron beam photoresist layer, and the method for performing photolithography on the photoresist layer includes:

[0013] Expose the photoresist layer using an electron beam;

[0014] The photoresist layer after the exposure process is developed to form the opening.

[0015] Optionally, in the method for manufacturing a semiconductor device, the mask layer is a positive ultraviolet photoresist layer, a positive ion beam photoresist layer or a positive X-ray photoresist layer.

[0016] Optionally, in the method for manufacturing the semiconductor device, the method for removing the mask layer includes:

[0017] The mask layer is subjected to full exposure processing and development processing in sequence to remove the mask layer.

[0018] Optionally, in the method for manufacturing a semiconductor device, the mask layer is a negative ultraviolet photoresist layer, a negative ion beam photoresist layer or a negative X-ray photoresist layer.

[0019] Optionally, in the method for manufacturing the semiconductor device, the method for removing the mask layer includes:

[0020] The mask layer is developed to remove the mask layer.

[0021] Optionally, in the method for manufacturing a semiconductor device, the mask layer is a photoresist shrink material layer.

[0022] Optionally, in the method for manufacturing the semiconductor device, the mask layer is removed by a wet cleaning process.

[0023] Optionally, in the method for manufacturing the semiconductor device, the cross-sectional shape of the opening is an inverted trapezoid, and the line width of the bottom of the opening is measured by a critical dimension scanning electron microscope.

[0024] In the manufacturing method of the semiconductor device provided by the present invention, the photoresist layer is first subjected to photolithography processing to form an opening in the photoresist layer; then, a mask layer is formed, the mask layer fills the opening and extends to cover the top surface of the photoresist layer, the photosensitive band of the mask layer is different from the photosensitive band of the photoresist layer, or the material of the mask layer is different from the material of the photoresist layer; then, the mask layer and the photoresist layer are subjected to heat treatment to fuse the contact surface of the mask layer and the photoresist layer to form a protective layer, the protective layer covers the side wall of the opening and the top surface of the photoresist layer; then, the mask layer is removed to expose the bottom of the opening; then, the line width at the bottom of the opening is measured. Since the protective layer covers the side wall of the opening and the top surface of the photoresist layer, when measuring the line width at the bottom of the opening, the protective layer can effectively prevent the profile of the photoresist layer from changing, thereby avoiding the profile of the opening in the photoresist layer from changing, that is, avoiding the side wall of the opening in the photoresist layer from expanding laterally, thereby avoiding the line width of the opening in the photoresist layer from changing. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic flow chart of a method for manufacturing a semiconductor device according to an embodiment of the present invention;

[0026] Figures 2 to 7 is a schematic diagram of a structure formed in a method for manufacturing a semiconductor device according to an embodiment of the present invention;

[0027] The reference numerals are described as follows:

[0028] 100 - substrate; 110 - photoresist layer; 110a - exposure area; 110b - non-exposure area; 111 - opening; 120 - mask layer; 130 - protective layer. DETAILED DESCRIPTION

[0029] The following is a further detailed description of the method for manufacturing a semiconductor device according to the present invention in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0030] As used in the present invention, the singular forms "one", "an", and "the" include plural objects, the term "or" is generally used to include the meaning of "and / or", the term "several" is generally used to include the meaning of "at least one", and the term "at least two" is generally used to include the meaning of "two or more". In addition, the terms "first", "second", and "third" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first", "second", and "third" may explicitly or implicitly include one or at least two of the features.

[0031] Figure 1 FIG. 1 is a flow chart of a method for manufacturing a semiconductor device provided by an embodiment of the present invention. Figure 1 As shown, this embodiment provides a method for manufacturing a semiconductor device, comprising:

[0032] Step S1: providing a substrate, on which a photoresist layer is formed, and the photoresist layer covers the substrate;

[0033] Step S2: performing photolithography on the photoresist layer to form an opening in the photoresist layer;

[0034] Step S3: forming a mask layer, wherein the mask layer fills the opening and extends to cover the top surface of the photoresist layer, the photosensitive band of the mask layer is different from the photosensitive band of the photoresist layer, or the material of the mask layer is different from the material of the photoresist layer;

[0035] Step S4: heating the mask layer and the photoresist layer to fuse the contact surfaces of the mask layer and the photoresist layer to form a protective layer, wherein the protective layer covers the sidewalls of the opening and the top surface of the photoresist layer;

[0036] Step S5: removing the mask layer to expose the bottom of the opening;

[0037] Step S6: measuring the line width of the bottom of the opening.

[0038] Figures 2 to 7 FIG. 1 is a schematic diagram of a structure formed in a method for manufacturing a semiconductor device according to an embodiment of the present invention. Figures 2 to 7 The method for manufacturing the semiconductor device provided in this embodiment is described in more detail.

[0039] First, refer to Figure 2As shown, step S1 is performed to provide a substrate 100, on which a photoresist layer 110 is formed, and the photoresist layer 110 covers the substrate 100. The substrate 100 may be at least one of the following materials: silicon, silicon on insulator (SOI), stacked silicon on insulator (SSOI), stacked silicon germanium on insulator (S-SiGeOI), silicon germanium on insulator (SiGeOI), germanium on insulator (GeOI), or silicon carbide, etc.

[0040] Optionally, an isolation structure may be formed in the substrate 100 , and the isolation structure may be a shallow trench isolation (STI) structure or a local oxide of silicon (LOCOS) isolation structure.

[0041] In addition, an active region may be defined in the substrate 100 , and other active devices may be included in the active region. In order to better illustrate the inventive point of the present invention, illustration of the active region and active devices is omitted in the drawings.

[0042] In this embodiment, Figure 2 As shown, a photoresist layer 110 is formed on the substrate 100. Preferably, the photoresist layer 110 is an electron beam photoresist layer to achieve fine pattern processing and to accurately define the exposure area of ​​the photoresist layer 110 in the subsequent exposure process, thereby ensuring the accuracy and consistency of the pattern.

[0043] The electron beam photoresist layer may be a positive electron beam photoresist layer, which may be formed by spin coating, spray coating, drop coating, screen printing, etc. The material of the electron beam photoresist layer may be polymethyl methacrylate, poly-α-trifluoroethyl chloroacrylate, polybutylene sulfone or polyhydrogen silsesquioxane.

[0044] In this embodiment, the thickness of the photoresist layer 110 may be 0.2 μm to 0.3 μm.

[0045] Next, refer to Figure 3 and Figure 4 As shown, step S2 is performed to perform photolithography on the photoresist layer 110 to form an opening 111 in the photoresist layer 110 , that is, the photoresist layer 110 is patterned.

[0046] Exemplarily, the process of performing photolithography on the photoresist layer 110 includes:

[0047] First, if Figure 3As shown, an electron beam is used to expose the photoresist layer 110, and an electron beam lithography machine can be used for exposure. During the exposure process, the electron beam lithography machine emits an electron beam, and the electron beam scans and exposes the photoresist layer 110 according to a pre-designed pattern, so that the electron beam deposits energy on the photoresist layer 110, thereby causing a chemical change in the exposure area 110a of the photoresist layer 110.

[0048] Then, if Figure 4 As shown, the photoresist layer 110 after the exposure process is developed to form an opening 111. Specifically, the process of the development process includes: placing the exposed photoresist layer 110 in a developer. During the development process, the photoresist in the exposure area 110a of the photoresist layer 110 is removed due to the increase in solubility, thereby forming an opening 111 in the photoresist layer 110, while the photoresist in the non-exposure area 110b is retained. Among them, the opening 111 runs through the photoresist layer 110, and the cross-sectional shape of the opening 111 is an inverted trapezoid, that is, the width of the opening 111 at the opening is greater than the width at the bottom.

[0049] In a further solution, a post-baking (PEB) process is performed after the development process, that is, the substrate 100 is dried after the development process to reduce the standing wave effect.

[0050] Next, refer to Figure 5 As shown, step S3 is performed to form a mask layer 120, the mask layer 120 fills the opening 111 and extends to cover the top surface of the photoresist layer 110, the photosensitive band of the mask layer 120 is different from the photosensitive band of the photoresist layer 110, or the material of the mask layer 120 is different from the material of the photoresist layer 110. The thickness of the mask layer 120 is 330 μm to 500 μm.

[0051] In this embodiment, the mask layer 120 is a positive ultraviolet photoresist layer, a positive ion beam photoresist layer, a positive X-ray photoresist layer, a negative ultraviolet photoresist layer, a negative ion beam photoresist layer or a negative X-ray photoresist layer, so that the photosensitivity band of the mask layer 120 is different from the photosensitivity band of the photoresist layer 110. In this way, damage to the photoresist layer 110 can be avoided in the subsequent process of removing the mask layer 120.

[0052] In another embodiment, the mask layer 120 is a photoresist retraction material layer, and the material of the mask layer 120 is different from the material of the photoresist layer 110, so that the photoresist layer 110 can be prevented from being damaged in the subsequent process of removing the mask layer 120. The material of the photoresist retraction material layer can be at least one of methacrylate and acrylate containing alkylamino groups.

[0053] Next, refer to Figure 6 As shown, step S3 is performed to heat the mask layer 120 and the photoresist layer 110 to fuse the contact surfaces of the mask layer 120 and the photoresist layer 110 to form a protective layer 130 , and the protective layer 130 covers the sidewalls of the opening 111 and the top surface of the photoresist layer 110 .

[0054] Specifically, the substrate 100 having the mask layer 120 and the photoresist layer 110 is placed in a heating device, which may be, for example, a hot plate, to heat the mask layer 120 and the photoresist layer 110. During the heating process, since the photoresist layer 110 and the mask layer 120 are both organic, the contact surfaces of the mask layer 120 and the photoresist layer 110 fuse to form the protective layer 130, that is, the top surface of the photoresist layer 110 and the bottom surface of the mask layer 120 fuse to form the protective layer 130. The protective layer 130 can protect the photoresist layer 110 during the subsequent line width measurement process, thereby preventing the profile of the photoresist layer 110 from changing, thereby preventing the profile of the opening 111 in the photoresist layer 110 from changing, and further preventing the line width of the opening 111 from changing.

[0055] Preferably, the temperature of the heating treatment is 90°C to 130°C, for example, 95°C, 100°C, 110°C, or 120°C. It should be noted that the temperature during the heating treatment should not be too high or too low. If the temperature during the heating treatment is too high, it is easy to cause heat diffusion inside the substrate 100, thereby damaging the substrate 100. If the temperature during the heating treatment is too low, it is easy to cause the contact surface between the photoresist layer 110 and the mask layer 120 to fail to fully contact and fuse. To this end, in the present embodiment, the temperature of the heating treatment is 90°C to 130°C to promote the interaction between the photoresist layer 110 and the mask layer 120, so that the photoresist layer 110 and the mask layer 120 can fully contact and fuse, and avoid high temperature damage to the substrate 100.

[0056] In a further solution, during the heating process, nitrogen gas may be introduced into the surface of the mask layer 120 to protect the mask layer 120 and prevent the mask layer 120 from undergoing an oxidation reaction.

[0057] Next, refer to Figure 7 As shown, step S5 is performed to remove the mask layer 120 to expose the bottom of the opening 111 .

[0058] In one embodiment, the mask layer 120 is a positive ultraviolet photoresist layer, a positive ion beam photoresist layer or a positive X-ray photoresist layer, and the method for removing the mask layer 120 includes: performing full exposure treatment and development treatment on the mask layer 120 in sequence to remove the mask layer 120, wherein the full exposure treatment means that during the exposure treatment, the entire surface of the mask layer 120 will be irradiated by the exposure light source.

[0059] During the exposure process, an exposure light source can be selected according to the photosensitive band of the mask layer 120. Specifically, if the mask layer 120 is a positive ultraviolet photoresist layer, an ultraviolet light source can be used for exposure; if the mask layer 120 is a positive ion beam photoresist layer, an ion beam can be used for exposure; if the mask layer 120 is a positive X-ray photoresist layer, an X-ray light can be used for exposure.

[0060] After the exposure process, the exposed mask layer 120 is developed to remove the mask layer 120. Specifically, a developer is sprayed onto the surface of the mask layer 120 to remove the exposed mask layer 120. The developer may be xylene or n-butyl acetate (nBA), and other suitable developers may also be used to develop and remove the exposed mask layer 120.

[0061] In one embodiment, the mask layer 120 is a negative ultraviolet photoresist layer, a negative ion beam photoresist layer or a negative X-ray photoresist layer, and the method for removing the mask layer 120 includes: performing a development process on the mask layer 120 to remove the mask layer 120. Since the mask layer 120 is a negative photoresist layer, the mask layer 120 can be directly removed by the development process. Specifically, a developer is sprayed onto the surface of the mask layer 120 to remove the unexposed mask layer 120.

[0062] In addition, since the photosensitivity band of the mask layer 120 is different from the photosensitivity band of the photoresist layer 110, and the protective layer 130 is formed by the fusion of the contact surface of the mask layer 120 and the photoresist layer 110, the protective layer 130 will not be removed by development during the development process of the mask layer 120.

[0063] In one embodiment, the mask layer 120 is a photoresist shrink material layer, and the mask layer 120 is removed by wet cleaning, wherein the solution used in the wet cleaning includes deionized water.

[0064] Next, step S6 is performed to measure the line width at the bottom of the opening 111. Preferably, the line width CD at the bottom of the opening 111 is measured by a critical dimension scanning electron microscope (Critical Dimension Scanning Electron Microscopy, CDSEM). Specifically, CDSEM uses a low-energy (1 keV or less) electron beam to scan the surface of the photoresist layer 110. When the electron beam interacts with the atoms on the surface of the photoresist layer 110, the surface of the photoresist layer 110 emits secondary electrons. The secondary electrons emitted from the surface of the photoresist layer 110 are collected to generate a corresponding image, thereby obtaining the line width CD at the bottom of the opening 111. Among them, the use of a low-energy electron beam can reduce damage to the surface of the photoresist layer 110.

[0065] In this embodiment, when measuring the line width at the bottom of the opening 111, since the protective layer 130 covers the side walls of the opening 111 and the top surface of the photoresist layer 110, the protective layer 130 can effectively prevent the profile of the photoresist layer 110 from changing, that is, avoid deformation of the profile of the photoresist layer 110, thereby avoiding changes in the profile of the opening 111, thereby avoiding changes in the line width at the bottom of the opening 111, and thus avoiding changes in the line width at the bottom of the opening 111, and the line width at the bottom of the opening 111 can be accurately obtained. Specifically, since the photoresist layer 110 is an electron beam photoresist layer, when measuring the line width of the opening, the electron beam emitted by the CDSEM will cause the contour of the opening 111 in the photoresist layer 110 to expand outward, thereby causing the line width of the opening to increase. However, since the protective layer 130 covers the side walls of the opening 111 and the top surface of the photoresist layer 110, during the process of measuring the line width of the opening, the protective layer 130 can effectively block the contour change of the photoresist layer 110, thereby avoiding changes in the line width of the opening in the photoresist layer 110, that is, avoiding lateral expansion of the side walls of the opening 111, thereby avoiding an increase in the line width of the opening 111, and further avoiding the problem of the measured line width being larger than the actual line width.

[0066] In this embodiment, the semiconductor device may be a product device or a test key.

[0067] In summary, in the manufacturing method of the semiconductor device provided by the embodiment of the present invention, the photoresist layer is first subjected to photolithography processing to form an opening in the photoresist layer; then, a mask layer is formed, the mask layer fills the opening and extends to cover the top surface of the photoresist layer, the photosensitive band of the mask layer is different from the photosensitive band of the photoresist layer, or the material of the mask layer is different from the material of the photoresist layer; then, the mask layer and the photoresist layer are subjected to heat treatment to fuse the contact surface of the mask layer and the photoresist layer to form a protective layer, the protective layer covers the side wall of the opening and the top surface of the photoresist layer; then; the mask layer is removed to expose the bottom of the opening; thereafter, the line width at the bottom of the opening is measured. Since the protective layer covers the side wall of the opening and the top surface of the photoresist layer, when measuring the line width at the bottom of the opening, the protective layer can effectively prevent the profile of the photoresist layer from changing, thereby avoiding the profile of the opening in the photoresist layer from changing, and further avoiding the line width of the opening in the photoresist layer from changing.

[0068] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

[0069] In addition, it should be recognized that although the present invention has been disclosed as a preferred embodiment, the above embodiment is not intended to limit the present invention. For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still belongs to the scope of protection of the technical solution of the present invention.

Claims

1. A method for manufacturing a semiconductor device, characterized in that: include: Providing a substrate, on which a photoresist layer is formed, and the photoresist layer covers the substrate; Performing photolithography on the photoresist layer to form an opening in the photoresist layer; forming a mask layer, wherein the mask layer fills the opening and extends to cover the top surface of the photoresist layer, the photosensitive band of the mask layer is different from the photosensitive band of the photoresist layer, or the material of the mask layer is different from the material of the photoresist layer; Heat-treating the mask layer and the photoresist layer so that the contact surfaces of the mask layer and the photoresist layer are fused to form a protective layer, wherein the protective layer covers the sidewalls of the opening and the top surface of the photoresist layer; removing the mask layer to expose the bottom of the opening; Measure the line width at the bottom of the opening.

2. The method for manufacturing a semiconductor device according to claim 1, wherein: The temperature of the heating treatment is 90°C to 130°C.

3. The method for manufacturing a semiconductor device according to claim 1, wherein: The photoresist layer is an electron beam photoresist layer, and the method for performing photolithography on the photoresist layer comprises: Expose the photoresist layer using an electron beam; The photoresist layer after the exposure process is developed to form the opening.

4. The method for manufacturing a semiconductor device according to claim 1, wherein: The mask layer is a positive ultraviolet photoresist layer, a positive ion beam photoresist layer or a positive X-ray photoresist layer.

5. The method for manufacturing a semiconductor device according to claim 4, wherein: The method for removing the mask layer comprises: The mask layer is subjected to full exposure processing and development processing in sequence to remove the mask layer.

6. The method for manufacturing a semiconductor device according to claim 1, wherein: The mask layer is a negative ultraviolet photoresist layer, a negative ion beam photoresist layer or a negative X-ray photoresist layer.

7. The method for manufacturing a semiconductor device according to claim 6, wherein: The method for removing the mask layer comprises: The mask layer is developed to remove the mask layer.

8. The method for manufacturing a semiconductor device according to claim 1, wherein: The mask layer is a photoresist shrink material layer.

9. The method for manufacturing a semiconductor device according to claim 8, wherein: The mask layer is removed by a wet cleaning process.

10. The method for manufacturing a semiconductor device according to claim 1, wherein: The cross-sectional shape of the opening is an inverted trapezoid, and the line width of the bottom of the opening is measured by a critical dimension scanning electron microscope.

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