Exposure method and method for manufacturing re-distribution layer

Abstract

This application provides an exposure method and a method for fabricating a redistribution layer. First, discrete distance data between the leveling lens and the photosensitive material layer in at least a portion of the exposure sub-regions within the exposure area is acquired in a direction perpendicular to the plane containing the photosensitive material layer. Next, the discrete distance data is fitted to obtain focal length plane data. Finally, the exposure lens is controlled to expose the corresponding photosensitive material layer within the exposure area according to a preset exposure path based on the focal length plane data. This method, by processing the pre-measured discrete distances into focal length plane data before using the exposure lens for exposure, effectively avoids exposure defocusing caused by abrupt changes in the height of the cutting area, ensuring the yield and quality of the redistribution layer fabrication.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing, and more specifically, to an exposure method and a method for preparing a redistribution layer. Background Technology

[0002] In the fabrication of redistribution layers (RDL) for board-level packaging, an exposure machine (e.g., a laser direct-write exposure machine) typically uses an exposure lens and a leveling lens (e.g., an FLS) in conjunction to expose the photosensitive material layer on the surface according to a preset exposure path to form the redistribution layer. However, due to the physical height difference between the dicing areas used for cutting adjacent chip cells, forming a significant step structure, the current exposure methods used in exposure machines are prone to exposure defocusing due to abrupt height changes in the dicing areas, thus affecting the yield of the redistribution layer fabrication. Summary of the Invention

[0003] To overcome the technical problems mentioned in the background, this application provides an exposure method for exposing a photosensitive material layer on a first substrate using an exposure lens based on focal length data obtained by a leveling lens. The first substrate includes at least one exposure area, which includes at least one exposure sub-area. Multiple first sub-areas for fabricating chip units are distributed within the exposure sub-area. Second sub-areas for forming dicing paths exist between adjacent first sub-areas. The photosensitive material layer is located on one side of the first substrate. The method includes: In a direction perpendicular to the plane containing the photosensitive material layer, obtain discrete distance data between the leveling lens and at least a portion of the photosensitive material layer within the exposure sub-region of the exposure area; The discrete distance data is fitted to obtain the focal plane data; The exposure lens is controlled to expose the corresponding photosensitive material layer within the exposure area according to the preset exposure path based on the focal length plane data.

[0004] In one possible implementation, the step of acquiring discrete distance data between the leveling lens and at least a portion of the photosensitive material layer within the exposure sub-region in a direction perpendicular to the plane containing the photosensitive material layer includes: In a direction perpendicular to the plane of the photosensitive material layer, acquire the first discrete distance data between the leveling lens and one of the exposure sub-regions of all the exposure areas; The step of fitting the discrete distance data to obtain the focal plane data includes: The first discrete distance data is fitted to obtain the first focal length plane data.

[0005] In one possible implementation, the method further includes: When abnormal first focal length plane data is detected at any position coordinate of the first focal length plane data, the abnormal first focal length plane data at the position coordinate is removed and replaced with the first focal length plane data at the corresponding position coordinate in an adjacent exposure area, or the average focal length plane data of the first focal length plane data at the corresponding position coordinates in multiple adjacent exposure areas is used as the replacement.

[0006] In one possible implementation, the step of controlling the exposure lens to expose the corresponding photosensitive material layer within the exposure area according to a preset exposure path based on the focal length plane data includes: The exposure lens is controlled to sequentially expose the photosensitive material layer in each exposure area on the first substrate based on the first focal length plane data.

[0007] In one possible implementation, the step of acquiring discrete distance data between the leveling lens and at least a portion of the photosensitive material layer within the exposure sub-region in a direction perpendicular to the plane containing the photosensitive material layer includes: Obtain the second discrete distance data between the leveling lens and the photosensitive material layer in all the exposure sub-regions of all exposure areas; The step of fitting the discrete distance data to obtain the focal plane data includes: The second discrete distance data is fitted to obtain the second focal length plane data.

[0008] In one possible implementation, the step of acquiring discrete distance data between the leveling lens and at least a portion of the photosensitive material layer within the exposure sub-region in a direction perpendicular to the plane containing the photosensitive material layer includes: The second discrete distance data between the exposure lens and the photosensitive material layer is acquired according to a preset scanning sequence.

[0009] In one possible implementation, the step of controlling the exposure lens to expose the corresponding photosensitive material layer within the exposure area according to a preset exposure path based on the focal length plane data includes: The exposure lens is controlled to sequentially expose the photosensitive material layer on the first substrate based on the second focal length plane data.

[0010] In one possible implementation, prior to the step of fitting the discrete distance data to obtain the focal plane data, the method further includes: The discrete distance data is preprocessed.

[0011] Another objective of this application is to provide a method for fabricating a redistribution layer, the method comprising: Provide a second substrate; An insulating layer is formed on one side of the second substrate; A seed layer is formed on the side of the insulating layer away from the second substrate; A photosensitive material layer is formed on the side of the seed layer away from the second substrate, and the photosensitive material layer is exposed using the aforementioned exposure methods provided in this application to form the exposed photosensitive material layer. After developing the exposed photosensitive material layer, the photosensitive material layer body is obtained and the seed layer is exposed through the photosensitive material layer window. Electroplating is performed on the exposed seed layer to obtain the trace, forming the trace layer; Repeat the above steps for fabricating the insulating layer and the wiring layer to fabricate the redistribution layer on the second substrate, in which the insulating layer and the wiring layer are arranged alternately.

[0012] In one possible implementation, after the step of obtaining the trace based on the exposed seed layer through electroplating to form the trace layer, the method further includes: Remove the photosensitive material layer body and the seed layer corresponding to the photosensitive material layer body.

[0013] Based on any of the above aspects, the present application provides an exposure method and a method for preparing a redistribution layer. First, discrete distance data between the leveling lens and the photosensitive material layer in at least a portion of the exposure sub-regions within the exposure area is acquired in a direction perpendicular to the plane where the photosensitive material layer is located. Next, the discrete distance data is fitted to obtain focal length plane data. Finally, the exposure lens is controlled to expose the corresponding photosensitive material layer within the exposure area according to a preset exposure path based on the focal length plane data. This scheme processes the discrete distance pre-measured by the leveling lens into focal length plane data, and then uses the exposure lens to perform exposure based on the focal length plane data. This effectively avoids exposure defocusing caused by abrupt changes in height in the cutting area, ensuring the yield and quality of the redistribution layer preparation. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings required in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the steps of an exposure method provided in this embodiment; Figure 2 This is a schematic diagram of the first substrate provided in this embodiment; Figure 3 This is a schematic diagram illustrating the scanning sequence of the first substrate provided in this embodiment; Figure 4 This is a schematic flowchart of a method for fabricating a redistribution layer provided in this embodiment; Figure 5a and Figure 5b for Figure 4 The corresponding manufacturing process diagram.

[0016] Icons: First substrate-10; Second substrate-20; Exposure area-AA1; Exposure sub-area-AA2; First sub-area-AB1; Second sub-area-AB2; Second substrate-20; Insulating layer-21; Seed layer-22; Photosensitive material layer-23; Photosensitive material layer body-230; Photosensitive material layer window-231; Wiring layer-24; Wiring-240. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0019] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0020] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0021] It should be noted that, where there is no conflict, different features in the embodiments of this application can be combined with each other.

[0022] The inventors discovered through research that in the fabrication process of redistribution layers (RDL) for board-level packaging, an exposure lens and a leveling lens (e.g., FLS) in an exposure machine (e.g., a laser direct-write exposure machine) are typically used in conjunction to expose the photosensitive material layer on the surface according to a preset exposure path to form the redistribution layer. Specifically, the leveling lens first measures the distance data between the exposure lens and the surface of the photosensitive material layer. Then, the exposure lens obtains the focal length data based on the measured distance data and adjusts the focal length before exposure. However, due to the physical height difference in the dicing areas between adjacent chip units, forming a significant step structure, the current exposure method used by the exposure machine causes height abrupt changes that exceed the instantaneous response capability of the exposure lens when passing through the dicing area. This results in an inability to effectively filter out abnormal values, leading to exposure defocusing and consequently affecting the yield of the redistribution layer.

[0023] In order to solve the aforementioned technical problems, the inventors have innovatively designed the following technical solutions, and the specific implementation scheme of this application will be described in detail below with reference to the accompanying drawings.

[0024] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic flowchart illustrating the steps of an exposure method provided in this embodiment. Figure 2This is a schematic diagram of the first substrate 10 provided in this embodiment. The exposure method is used to expose the photosensitive material layer on the first substrate 10 using an exposure lens based on focal length data obtained by a leveling lens. The first substrate 10 includes at least one exposure region AA1, and each exposure region AA1 includes at least one exposure sub-region AA2. Multiple first sub-regions AB1 for fabricating chip units are distributed within each exposure sub-region AA2. Second sub-regions AB2 for forming dicing paths exist between adjacent first sub-regions AB1. The photosensitive material layer is located on one side of the first substrate 10. In this embodiment, when there are multiple exposure regions AA1, the first substrate 10 includes multiple exposure sub-regions AA2 arranged in the same exposure region AA1. When there are multiple exposure sub-regions AA2 within multiple exposure regions AA1, the exposure sub-regions AA2 are periodically arranged within the exposure regions AA1. For example, the first substrate 10 is divided into multiple strip-shaped first substrates 10 (e.g., strips), each strip serving as an exposure region AA1, and each strip including multiple periodically arranged exposure sub-regions AA2.

[0025] In this embodiment, the first sub-region AB1 is used to form a chip unit, the second sub-region AB2 is used to form a cutting channel, and the second sub-region AB2 is recessed between adjacent second sub-regions AB2.

[0026] The following is combined Figure 1 and Figure 2 This exposure method will be explained in detail.

[0027] Step S11: In the direction perpendicular to the plane where the photosensitive material layer is located, obtain discrete distance data between the leveling lens and the photosensitive material layer in at least a portion of the exposure sub-region AA2 within the exposure area AA1.

[0028] In this step, the vertical distance between the exposure area AA1 and at least part of the exposure sub-area AA2 within the exposure area AA1 is measured in advance using a leveling lens (e.g., a focusing leveling lens FLS) to obtain a series of discrete distance sampling points, which constitute discrete distance data.

[0029] In this embodiment, on the one hand, discrete distance data can be obtained by scanning only one period of exposure sub-region AA2 in all exposure areas AA1 with a leveling lens; on the other hand, discrete distance data can be obtained by scanning all periods of exposure sub-region AA2 in all exposure areas AA1 with a leveling lens, so as to adapt to different accuracy and efficiency requirements.

[0030] Step S12: Fit the discrete distance data to obtain focal plane data.

[0031] In this embodiment, the fitting process can employ algorithms such as least squares interpolation and spline interpolation to fit the discrete distance data into a continuous, smooth two-dimensional surface, i.e., focal length plane data. This focal length plane data reflects the focal length value that the exposure lens should maintain at each position coordinate on the first substrate 10.

[0032] Step S13: Control the exposure lens to expose the corresponding photosensitive material layer in the exposure area AA1 according to the preset exposure path based on the focal length plane data.

[0033] In this embodiment, since the focal length plane data represents the focal length values ​​at different coordinates on the first substrate 10, the focal length of the exposure lens is dynamically adjusted according to the focal length plane data during the exposure process. For example, when the exposure lens is about to scan the dicing area, it can adjust the focal length in advance. In this way, the exposure defocus caused by the height change of the dicing area can be effectively avoided, and the preparation yield and quality of the redistribution layer can be guaranteed.

[0034] Furthermore, in one embodiment of this invention, focal plane data can be fitted and formed by periodic sampling. Specifically, firstly, step S11 can be implemented as follows: in a direction perpendicular to the plane where the photosensitive material layer is located, first discrete distance data between the leveling lens and one exposure sub-region AA2 among all exposure regions AA1 is obtained. In this embodiment, one period is formed on the first substrate 10 by one exposure sub-region AA2 among all exposure regions AA1, that is, only one period of exposure sub-region AA2 on the first substrate 10 is scanned to obtain the first discrete height data of one period. For example, as shown... Figure 2 As shown, if a first substrate 10 is divided into 5 exposure areas AA1, each exposure area AA1 includes a first exposure sub-region and a second exposure sub-region. The first exposure sub-region and the second exposure sub-region are distributed in the same way. Then the first exposure sub-region of the 5 exposure areas AA1 is a cycle. The distance between the photosensitive material layer and the exposure lens in the scanned cycle is used as the first discrete height data.

[0035] Next, step S12 can be implemented as follows: the first discrete distance data is fitted to obtain the first focal length plane data. In this embodiment, since there is a high correlation between the exposure areas AA1 on the first substrate 10, the high correlation can be effectively utilized to fit the first discrete distance data to obtain the first focal length plane data corresponding to all exposure areas AA1.

[0036] Furthermore, the method also includes: When abnormal first focal plane data is detected at any position coordinate of the first focal plane data, the abnormal first focal plane data at the position coordinate is removed and replaced by the first focal plane data at the corresponding position coordinate in an adjacent exposure area AA1, or the average focal plane data of the first focal plane data at the corresponding position coordinates in multiple adjacent exposure areas is used as the replacement.

[0037] In this embodiment, when an anomaly occurs in the first focal length plane data at any position coordinate, for example, due to outliers caused by dust or measurement noise, the first focal length plane data at the corresponding position coordinate in an adjacent exposure area AA1 can be used instead. In one implementation of this embodiment, the first focal length plane data at the corresponding position coordinate in an adjacent exposure area AA1 is used instead. In another implementation of this embodiment, the average focal length plane data at the corresponding position coordinates of multiple adjacent exposure areas AA1 is used instead. For example, the average focal length plane data can be obtained by averaging the first focal length plane data at the corresponding position coordinates of two adjacent exposure areas AA1, and this average focal length plane data can be used to replace the abnormal first focal length plane data in the exposure area AA1. Since adjacent exposure areas AA1 are highly similar, the first focal length plane data or average focal length plane data at the corresponding position coordinates of the exposure sub-region AA2 of adjacent exposure areas AA1 located within the same period are used instead, thus significantly improving the accuracy and reliability of the focal length plane data.

[0038] Furthermore, step S13 can be implemented in the following way.

[0039] The exposure lens is controlled to sequentially expose the photosensitive material layer in each exposure area AA1 on the first substrate 10 based on the first focal length plane data.

[0040] In this embodiment, the exposure lens follows a preset exposure path and uses the first focal length plane data to adjust the focus height in real time, thereby ensuring the focus stability when crossing the cutting path and effectively avoiding the phenomenon of exposure defocus.

[0041] In the above scheme, the first focal length plane data of all exposure areas AA1 is calculated by using periodic first discrete distance data, which significantly reduces scanning costs and can effectively utilize the high correlation characteristics of adjacent exposure areas AA1, thereby maximizing production efficiency while ensuring the accuracy of the first focal length plane data.

[0042] Furthermore, in another embodiment of this invention, focal length plane data can be formed by fitting using global sampling. Specifically, firstly, step S11 can also be implemented by obtaining the second discrete distance data between the leveling lens and the photosensitive material layers in all exposure sub-regions AA2 of all exposure areas AA1. In this embodiment, the second discrete focal length data is obtained by scanning the photosensitive material layers in all exposure sub-regions AA2 of all exposure areas AA1 on the first substrate 10. For example, as shown... Figure 2 As shown, if a first substrate 10 is divided into 5 exposure areas AA1, and each exposure area AA1 includes a first exposure sub-region and a second exposure sub-region, then the distance between the photosensitive material layer of the first exposure sub-region and the exposure lens of the 5 exposure areas AA1 is used as the second discrete height data.

[0043] Next, step S12 can also be implemented by fitting the second discrete distance data to obtain the second focal plane data. In this embodiment, the global focal plane model, i.e., the second focal plane data, is obtained by directly fitting the acquired second discrete distance data, which can meticulously depict the local warping and steep changes at the edge of the cutting path steps.

[0044] Furthermore, step S11 can also be implemented in the following ways.

[0045] The second discrete distance data between the leveling lens and the photosensitive material layer is acquired according to the preset scanning sequence.

[0046] In this embodiment, please refer to Figure 3 , Figure 3 This is a schematic diagram of the scanning sequence of the first substrate 10 provided in this embodiment. The preset scanning sequence is as follows: Figure 3 As indicated by the middle arrow, the scanning sequence includes either serpentine scanning or line-by-line scanning to comprehensively measure the distance between the leveling lens and the photosensitive material layer.

[0047] Furthermore, step S13 can also be implemented in the following way: The exposure lens is controlled to sequentially expose the photosensitive material layer on the first substrate 10 based on the second focal length plane data. In this embodiment, the second focal length plane data includes the focal length values ​​at all position coordinates of the first substrate 10. During the exposure process, the exposure lens dynamically focuses according to the second focal length plane data.

[0048] In the above scheme, the second focal length plane data is obtained by pre-scanning the second discrete distance data between the whole plate photosensitive material layer and the leveling lens, and the exposure lens is controlled to use the second focal length plane data for exposure, which significantly improves the focusing accuracy of the exposure lens, has strong adaptability to ultra-large height differences and complex steps, and can fundamentally avoid exposure defocus caused by sudden changes in height in the cutting area.

[0049] Furthermore, prior to step S12, the method further includes: Perform preprocessing operations on discrete distance data.

[0050] In this embodiment, the preprocessing operations on the discrete distance data include, but are not limited to, denoising operations on the discrete distance data, such as removing isolated noise points through median filtering. This can effectively improve the quality of the fitted data and reduce the interference of outliers on the focal plane data.

[0051] Another objective of this application is to provide a method for fabricating a redistribution layer. Please refer to [link to relevant documentation]. Figure 4 , Figure 5a and Figure 5b , Figure 4 This is a schematic flowchart illustrating the steps of a redistribution layer fabrication method provided in this embodiment. Figure 5a and Figure 5b right Figure 4 The corresponding process flow chart. Methods include: Step S21: Provide a second substrate 20.

[0052] In this step, the second substrate 20 can be a glass substrate.

[0053] In step S22, an insulating layer 21 is formed on one side of the second substrate 20.

[0054] Step S23: A seed layer 22 is formed on the side of the insulating layer 21 away from the second substrate 20.

[0055] In this step, a seed layer 22 can be prepared by physical vapor deposition to provide a conductive path for subsequent electroplating.

[0056] Step S24: A photosensitive material layer 23 is formed on the side of the seed layer 22 away from the second substrate 20, and the photosensitive material layer 23 is exposed using the aforementioned exposure methods provided in this application to form the exposed photosensitive material layer 23.

[0057] In this step, first focal length plane data can be obtained by fitting first discrete distance data between the exposure lens and the photosensitive material layer 23 in one period of exposure sub-regions in all exposure areas. Alternatively, second focal length plane data can be obtained by fitting second discrete distance data between the exposure lens and the photosensitive material layer 23 in all exposure sub-regions in all exposure areas. The exposure lens then exposes the photosensitive material layer 23 according to either the first or second focal length plane data.

[0058] Step S25 involves developing the exposed photosensitive material layer 23 to obtain the photosensitive material layer body 230 and exposing the seed layer 22 through the photosensitive material layer window 231.

[0059] Step S26: Electroplating is performed on the exposed seed layer 22 to obtain the trace 240, forming the trace layer 24.

[0060] In this step, the electroplating based on the exposed seed layer 22 can be done with a copper electroplating layer, and the groove formed by the seed layer 22 and the photosensitive material layer window 231 is filled with metal.

[0061] Step S27: Repeat the above steps for fabricating the insulating layer 21 and the wiring layer 24 to fabricate a redistribution layer on the second substrate in which the insulating layer 21 and the wiring layer 24 are arranged alternately.

[0062] In the above scheme, the exposure method described above ensures that the image of the trace 240 in the trace layer 24 is complete and the line width is uniform, thereby ensuring the overall yield of the rewiring layer.

[0063] Furthermore, after step S26, the method further includes: Remove the photosensitive material layer body 230 and the seed layer 22 corresponding to the photosensitive material layer body 230.

[0064] In this embodiment, the photosensitive material layer body 230 and the seed layer 22 corresponding to the photosensitive material layer body 230 can be removed by etching.

[0065] In summary, the exposure method and redistribution layer fabrication method provided in this application firstly acquire discrete distance data between the leveling lens and the photosensitive material layer in at least a portion of the exposure sub-regions within the exposure area, in a direction perpendicular to the plane containing the photosensitive material layer. Next, the discrete distance data is fitted to obtain focal length plane data. Finally, the exposure lens is controlled to expose the corresponding photosensitive material layer within the exposure area according to a preset exposure path based on the focal length plane data. This scheme, by processing the discrete distances pre-measured by the leveling lens into focal length plane data before using the exposure lens for exposure, effectively avoids exposure defocusing caused by abrupt changes in the height of the cutting area, ensuring the yield and quality of the redistribution layer fabrication.

[0066] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An exposure method, characterized in that, A method for exposing a photosensitive material layer on a first substrate using an exposure lens based on focal length data acquired by a leveling lens, wherein the first substrate includes at least one exposure area, the exposure area includes at least one exposure sub-area, the exposure sub-area has a plurality of first sub-areas for fabricating chip units distributed therein, and there are second sub-areas for forming dicing paths between adjacent first sub-areas, the photosensitive material layer is located on one side of the first substrate, the method comprising: In a direction perpendicular to the plane containing the photosensitive material layer, obtain discrete distance data between the leveling lens and at least a portion of the photosensitive material layer within the exposure sub-region of the exposure area; The discrete distance data is fitted to obtain focal plane data; The exposure lens is controlled to expose the corresponding photosensitive material layer within the exposure area according to the preset exposure path based on the focal length plane data.

2. The exposure method according to claim 1, wherein The step of acquiring discrete distance data between the leveling lens and at least a portion of the photosensitive material layers within the exposure sub-region in a direction perpendicular to the plane containing the photosensitive material layer includes: In a direction perpendicular to the plane of the photosensitive material layer, acquire the first discrete distance data between the leveling lens and one of the exposure sub-regions of all the exposure areas; The step of fitting the discrete distance data to obtain the focal plane data includes: The first discrete distance data is fitted to obtain the first focal length plane data.

3. The exposure method according to claim 2, wherein The method further includes: When abnormal first focal length plane data is detected at any position coordinate of the first focal length plane data, the abnormal first focal length plane data at the position coordinate is removed and replaced with the first focal length plane data at the corresponding position coordinate in an adjacent exposure area, or the average focal length plane data of the first focal length plane data at the corresponding position coordinates in multiple adjacent exposure areas is used as the replacement.

4. The exposure method according to claim 2, wherein The step of controlling the exposure lens to expose the corresponding photosensitive material layer within the exposure area according to the focal length plane data and a preset exposure path includes: The exposure lens is controlled to sequentially expose the photosensitive material layer in each exposure area on the first substrate based on the first focal length plane data.

5. The exposure method according to claim 1, wherein The step of acquiring discrete distance data between the leveling lens and at least a portion of the photosensitive material layers within the exposure sub-region in a direction perpendicular to the plane containing the photosensitive material layer includes: Obtain the second discrete distance data between the leveling lens and the photosensitive material layer in all the exposure sub-regions of all exposure areas; The step of fitting the discrete distance data to obtain the focal plane data includes: The second discrete distance data is fitted to obtain the second focal length plane data.

6. The exposure method according to claim 5, wherein The step of acquiring discrete distance data between the leveling lens and at least a portion of the photosensitive material layers within the exposure sub-region in a direction perpendicular to the plane containing the photosensitive material layer includes: The second discrete distance data between the leveling lens and the photosensitive material layer is acquired according to a preset scanning sequence.

7. The exposure method according to claim 5, wherein The step of controlling the exposure lens to expose the corresponding photosensitive material layer within the exposure area according to the focal length plane data and a preset exposure path includes: The exposure lens is controlled to sequentially expose the photosensitive material layer on the first substrate based on the second focal length plane data.

8. The exposure method according to claim 1, wherein Before the step of fitting the discrete distance data to obtain the focal plane data, the method further includes: The discrete distance data is preprocessed.

9. A method for fabricating a redistribution layer, characterized in that, The method includes: Provide a second substrate; An insulating layer is formed on one side of the second substrate; A seed layer is formed on the side of the insulating layer away from the second substrate; A photosensitive material layer is formed on the side of the seed layer away from the second substrate, and the photosensitive material layer is exposed using the exposure method described in any one of claims 1-8 to form the exposed photosensitive material layer. After developing the exposed photosensitive material layer, the photosensitive material layer body is obtained and the seed layer is exposed through the photosensitive material layer window. Electroplating is performed on the exposed seed layer to obtain the trace, forming the trace layer; Repeat the above steps for fabricating the insulating layer and the wiring layer to fabricate the redistribution layer on the second substrate, in which the insulating layer and the wiring layer are arranged alternately.

10. The method for fabricating a redistribution layer as described in claim 9, characterized in that, After the step of obtaining the trace layer by electroplating the exposed seed layer, the method further includes: Remove the photosensitive material layer body and the seed layer corresponding to the photosensitive material layer body.

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