Circuit board manufacturing method, circuit board and electronic equipment

Abstract

The invention relates to a circuit board manufacturing method, a circuit board and electronic equipment. The circuit board manufacturing method comprises the following steps: providing a substrate provided with a via hole; a first photosensitive film layer is formed on the substrate. The first photosensitive film layer comprises a first light shielding part and a first exposure part arranged around the first light shielding part. At least part of the first light shielding part covers the via hole, and at least part of the first exposure part covers the periphery of the hole opening of the via hole. And exposing and developing the first photosensitive film layer, retaining the first exposure part and removing the first light shielding part to form a first processing substrate. And performing electroplating treatment on the first processing substrate, so that a first metal layer is attached to the hole wall of at least part of the via holes. The circuit board manufacturing method is beneficial to reducing copper electroplating consumables in the electroplating process of the circuit board, the surface thickness of the circuit board is reduced, the uniformity of the circuit board is improved, and in addition, the thickness of an electroplating metal layer is ensured.

Description

Technical Field

[0001] The present application relates to the technical field of circuit board processing, and in particular to a circuit board manufacturing method, a circuit board and an electronic device. Background Art

[0002] Generally, the current conduction between different components arranged on the circuit board is actually achieved through the metal layer on the inner wall of the conductive hole on the circuit board.

[0003] Based on this, in the production process of circuit boards, the circuit boards are often drilled and then copper-plated. The processing of the via holes of the circuit board is as follows: first, a photosensitive layer is attached to the surface of the circuit board, and then exposed and developed to form a processing area around the via hole. Finally, a copper layer is formed in the processing area through electroplating.

[0004] However, in the actual processing, the processing area is usually large, not only covering the via hole, but also covering the substrate surrounding the via hole, so that in the actual electroplating process, there are the following problems: First, due to the copper foil of the substrate itself, the substrate on the processing area will also be electroplated to form a copper layer during the electroplating process, which increases the use of electroplated copper and increases the thickness of the circuit board, resulting in uneven production of the circuit board. Second, the thickness of the electroplated copper is limited, and the electroplated metal is easy to overflow on the surface of the substrate, which is easy to cause uneven electroplated copper layer. Summary of the invention

[0005] Based on this, it is necessary to provide a circuit board manufacturing method, a circuit board and an electronic device to address the problems of increased copper plating consumables, increased circuit board surface thickness, and insufficient and uneven thickness of the electroplated metal layer during the electroplating process of the circuit board.

[0006] A method for manufacturing a circuit board, comprising:

[0007] Providing a substrate having a through hole;

[0008] A first photosensitive film layer is formed on the substrate; the first photosensitive film layer comprises a first light-shielding portion covering the via hole and a first exposure portion arranged around the first light-shielding portion; the first exposure portion partially covers the opening of the via hole;

[0009] exposing and developing the first photosensitive film layer, retaining the first exposed portion and removing the first light-shielding portion, so as to form a first processed substrate;

[0010] The first processed substrate is electroplated so that a first metal layer is attached to at least a portion of the hole walls of the via holes.

[0011] In one embodiment, the orthographic projection area of ​​the first light shielding portion on the substrate is located inside the orthographic projection area of ​​the hole wall of the via hole on the substrate.

[0012] In one embodiment, a difference between a diameter of the via hole and a diameter of the first light shielding portion is a first difference; and the first difference is between 0.5 mil and 3.5 mil.

[0013] In one embodiment, the step of forming the first photosensitive film layer on the substrate includes:

[0014] The first photosensitive film layer includes a first dry film layer and a first light shielding layer;

[0015] coating the first dry film layer on the substrate; the first dry film layer comprises the first light-shielding portion and the first exposure portion;

[0016] The first light shielding layer is formed on the first dry film layer; the first light shielding layer includes a plurality of light shielding portions arranged at intervals; the light shielding portions are arranged corresponding to the through holes one by one; the light shielding portions are arranged to cover the first light shielding portions, so that the first light shielding portions are arranged to be light-proof;

[0017] The area of ​​the orthographic projection region of the light shielding portion in the first direction is smaller than the area of ​​the orthographic projection region of the conducting hole in the first direction, and the first direction is the arrangement direction of the substrate and the first photosensitive film layer.

[0018] In one of the embodiments, the first light-shielding layer further includes a light-transmitting portion disposed around the light-shielding portion; the light-transmitting portion is disposed corresponding to the first exposure portion, so that the first exposure portion is exposed through the light-transmitting portion.

[0019] In one embodiment, the step of forming a first photosensitive film layer on the substrate includes:

[0020] The substrate comprises a first surface and a second surface which are arranged opposite to each other along a first direction; the first photosensitive film layer is formed on both the first surface and the second surface; and the first direction is the arrangement direction of the substrate and the first photosensitive film layer.

[0021] In one embodiment, the circuit board manufacturing method further includes:

[0022] After electroplating the first processed substrate, the first exposure portion is removed to form a second processed substrate;

[0023] forming a second photosensitive film layer on the second processed substrate, wherein the second photosensitive film layer comprises a second light-shielding portion and a second exposure portion disposed around the second light-shielding portion; the second light-shielding portion is disposed to cover the conducting hole;

[0024] exposing and developing the second photosensitive film layer, retaining the second exposed portion and removing the second light-shielding portion, so as to form a third processed substrate;

[0025] The third processed substrate is electroplated so that a second metal layer is attached to at least a portion of the hole wall of the through hole, and at least a portion of the second metal layer is stacked with the first metal layer; wherein the orthographic projection of the second light-shielding portion on the substrate is located inside the orthographic projection of the first light-shielding portion on the substrate.

[0026] In one embodiment, the circuit board manufacturing method further includes:

[0027] After electroplating the first processed substrate, the first exposure portion is removed to form a second processed substrate;

[0028] A second photosensitive film layer is formed on the second processed substrate; the second photosensitive film layer includes a second dry film layer and a second light shielding layer.

[0029] wherein, forming the second dry film layer on the second processed substrate;

[0030] The second light-shielding layer is formed on the second dry film layer; the second light-shielding layer includes a plurality of light-shielding patterns and light-transmitting patterns arranged adjacent to the light-shielding patterns.

[0031] The second photosensitive film layer is exposed and developed to remove the light-shielding pattern and the second dry film layer disposed on the light-shielding pattern, and the second dry film layer disposed on the light-transmitting pattern is retained to form a fourth processed substrate.

[0032] A circuit board is manufactured by the circuit board manufacturing method in the above embodiment.

[0033] An electronic device includes the circuit board in the above embodiment.

[0034] The above-mentioned circuit board manufacturing method, circuit board and electronic device, in this way, by forming the first metal layer on the hole wall of the via hole, a conductive layer is formed on the hole wall of the via hole, which can cooperate with other components to realize the conduction of the circuit. Further, by setting the first light-shielding portion, it can be ensured that at least part of the upper surface of the substrate arranged around the via hole can be covered by the photosensitive film layer, so that at least part of the outer layer of circuit protection can be formed on part of the upper surface of the substrate, preventing the copper layer from being electroplated on part of the circuit board during the electroplating process, reducing the range of metal electroplating on the copper foil of the substrate, thereby reducing the consumption of electroplating materials, and avoiding the increase of the thickness of part of the circuit board, which is conducive to improving the thickness uniformity of the circuit board, and then facilitating the subsequent etching process operation.

[0035] In addition, the first photosensitive film layer corresponding to the first exposure portion does not dissolve during development, so that at least a portion of the first photosensitive film layer corresponding to the first exposure portion is protruded on the periphery of the hole mouth of the via, and is suspended above the via. The protruding portion of the first photosensitive film layer can provide a moving limit for the electroplated metal to prevent the electroplated metal from overflowing to the surface of the substrate before the thickness is reached. Instead, the electroplated metal is blocked by the protruding portion of the photosensitive film layer, so that the electroplated metal continues to be plated to the inner wall of the via, thereby ensuring the thickness of the electroplated metal in the via, and ensuring the conductive performance of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the structure of an electroplated metal layer on a substrate in the related art.

[0037] Figure 2 FIG. 1 is a top view of a circuit board in one embodiment of the present application.

[0038] Figure 3 Schematic diagram of the process of manufacturing a circuit board in one embodiment of the present application.

[0039] Figure 4 It is a cross-sectional view of the installation structure of the first photosensitive film layer on the substrate in one embodiment.

[0040] Figure 5 It is a cross-sectional view of the installation structure of the first metal layer on the first processing substrate in one embodiment.

[0041] Figure 6 Schematic diagram of the manufacturing process of the first photosensitive film layer in one embodiment of the present application.

[0042] Figure 7 Schematic diagram of a process for processing a second metal layer on a substrate in one embodiment of the present application.

[0043] Figure 8 4 is a cross-sectional view of an installation structure of a second photosensitive film layer on a substrate in one embodiment.

[0044] Fig. 9 Schematic diagram of the coordination structure between the second metal layer and the first metal layer in one embodiment.

[0045] Fig.10 It is a schematic diagram of the production process of etching a substrate in one embodiment of the present application.

[0046] Description of reference numerals:

[0047] 100, substrate; 110, via hole; 200, first photosensitive film layer; 210, first light-shielding portion; 220, first exposure portion; 300, first metal layer; 400, second photosensitive film layer; 410, second light-shielding portion; 420, second exposure portion; 500, second metal layer. DETAILED DESCRIPTION

[0048] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0049] See also Figure 1 , Figure 1 It is not difficult to find that the metal layer a formed after electroplating in the related art is not only arranged on the inner side wall of the via hole 110, but also arranged on the upper surface of the substrate 100, resulting in uneven thickness of the substrate 100 and making it difficult to remove the metal layer later.

[0050] Based on this, Figure 2 As shown, the present application provides a cross-sectional view of a circuit board. The circuit board in the present application is manufactured by a circuit board manufacturing method.

[0051] Generally, the circuit board is provided with corresponding through holes 110 before electroplating, and the circuit board can be of various types, such as a flexible circuit board.

[0052] Specifically, Figures 3 to 5 As shown, the circuit board manufacturing method includes:

[0053] S1. Provide a substrate 100 having a through hole 110 .

[0054] S2 . Forming a first photosensitive film layer 200 on the substrate 100 .

[0055] like Figure 4 As shown, the first photosensitive film layer 200 includes a first light-shielding portion 210 and a first exposure portion 220 disposed around the first light-shielding portion 210. The first light-shielding portion 210 is disposed on the conductive hole 110, and the first exposure portion 220 partially covers the opening of the conductive hole 110, so that the first exposure portion 220 partially protrudes from the periphery of the opening of the conductive hole 110. It should be noted that the first photosensitive film layer 200 can be disposed on the upper surface, the lower surface, or both of the substrate 100.

[0056] S3, exposing and developing the first photosensitive film layer 200, removing the first light-shielding portion 210 and retaining the first exposure portion 220, to form a first processed substrate.

[0057] It is understandable that the first photosensitive film layer 200 (i.e., the first exposure part 220) that has been subjected to the exposure treatment cannot be dissolved in the developer, while the first photosensitive film layer 200 (i.e., the first light-shielding part 210) that has not been subjected to the exposure treatment can be dissolved in the developer. Therefore, when the circuit board that has been subjected to the exposure treatment is immersed in the developer for development, since the first photosensitive film layer 200 of the first light-shielding part 210 is detached, at least part of the first exposure part 220 is still covered on the copper foil of the substrate 100. There are many ways of exposure, such as ultraviolet light irradiation, and other areas are at least partially covered by dry film and light-transmitting areas.

[0058] Based on this, since the first light-shielding portion 210 is covered on the conductive hole 110, after exposure and development, the photosensitive film layer corresponding to the first light-shielding portion 210 will dissolve in the developer, so that the conductive hole 110 is in a state of being connected to the outside, and the photosensitive film layer corresponding to the first exposure portion 220 is insoluble in the developer, so that at least part of the photosensitive film layer corresponding to the first exposure portion 220 covers the periphery of the hole opening of the conductive hole 110, which can be just flush with the periphery of the hole opening of the conductive hole 110, or can be protruding from the periphery of the hole opening and suspended above the conductive hole 110.

[0059] S4, electroplating the first processed substrate, so that the first metal layer 300 is attached to at least a portion of the hole wall of the via hole 110, so that part of the first metal layer 300 is electroplated on the inner wall of the via hole 110 corresponding to the first exposure part 220 (for example, part of the first metal layer 300 is electroplated on the inner wall of the via hole 110 directly below the first exposure part 220). Specifically, the first metal layer 300 can be a variety of metal materials or a combination of metal materials, such as a copper layer, a tin layer, a copper-tin layer, etc.

[0060] See also Figure 5 Thus, by attaching the first metal layer 300 to the hole wall of the via hole 110, a conductive layer is formed on the hole wall of the via hole 110, which can cooperate with other components to realize the conduction of the circuit. Furthermore, by setting the first light shielding portion 210 at the periphery of the hole opening of the via hole 110, it can be ensured that at least part of the upper surface of the substrate 100 set around the via hole 110 can be covered by the first photosensitive film layer 200, so that at least part of the outer layer of circuit protection can be formed on part of the upper surface of the substrate 100, preventing the copper layer from being electroplated on the circuit board of this part during the electroplating process, reducing the range of metal electroplating on the copper foil of the substrate, avoiding the increase of the thickness of part of the circuit board, which is conducive to improving the uniformity of the surface thickness of the circuit board, and then facilitating the subsequent etching process operation.

[0061] In addition, the first photosensitive film layer 200 corresponding to the first exposure portion 220 is not dissolved in the developer, and at least part of the first photosensitive film layer 200 corresponding to the first exposure portion 220 is convexly disposed on the periphery of the opening of the via hole 110, and is suspended above the via hole 110. The convexly disposed first photosensitive film layer 200 can provide a moving limit for the electroplated metal, thereby preventing the electroplated metal from overflowing to the surface of the substrate 100 before the thickness is reached. The convexly disposed first photosensitive film layer 200 blocks the electroplated metal from continuing to be electroplated to the inner side wall of the via hole 110, thereby ensuring the thickness of the electroplated metal in the via hole 110, which is beneficial to improving the uniformity of the first metal layer 300 and ensuring the conductive performance of the circuit board.

[0062] It should be noted that there may be various types of photosensitive film layers, such as negative photoresist, dry film and other photosensitive materials.

[0063] In one embodiment, Figure 2 The orthographic projection area of ​​the first light shielding portion 210 on the substrate 100 is located inside the orthographic projection area of ​​the hole wall of the conducting hole 110 on the substrate 100 .

[0064] Based on this, after the first photosensitive film layer 200 is exposed and developed, due to the dissolution of the first light-shielding portion 210 in the developer, at least one opening is formed in the first photosensitive film layer 200, and the opening is connected to the opening of the conductive hole 110, and the area of ​​the opening is smaller than the opening area of ​​the conductive hole 110, thereby ensuring that the photosensitive film layer of the first exposure portion 220 protrudes around the opening wall of the conductive hole 110.

[0065] In this way, it can be ensured that the upper surface of the substrate 100 arranged around the periphery of the via hole 110 can be completely covered by the first exposure portion 220, and it can be ensured that the electroplated first metal layer 300 will not be electroplated to the upper surface of the substrate 100 around the opening of the via hole 110, but will only be electroplated on the hole wall of the via hole 110, thereby limiting the range of electroplating on the copper foil of the substrate 100 to the greatest extent, making the surface thickness of the substrate 100 more uniform.

[0066] Furthermore, when the orthographic projection area of ​​the first light shielding portion 210 on the substrate 100 is located inside the orthographic projection area of ​​the hole wall of the via hole 110 on the substrate 100, the first exposure portion 220 after exposure and development can have a circle of baffle convex ring protruding on the periphery of the hole mouth of the via hole 110. The baffle convex ring can not only prevent the first metal layer 300 from overflowing and being plated to the upper surface of the substrate 100, forming a movement barrier for the plated metal, so that the plating thickness of the plated metal can be met, the conductive performance of the circuit board is ensured, and the first metal layer 300 is evenly distributed on the inner wall of the via hole 110.

[0067] In addition, the baffle convex ring can also be used as a way to observe the progress of electroplating. Specifically, when the first metal layer 300 is observed at the edge of the baffle convex ring, the first metal layer 300 has reached an optimal thickness and the electroplating can be stopped.

[0068] Specifically, in one example, the difference between the diameter of the via 110 and the diameter of the first light shielding portion 210 is a first difference, and the first difference is between 0.5 mil and 3.5 mil. That is, the width of the baffle convex ring in the above embodiment is the first difference, and the width range is 0.5 mil to 3.5 mil. In this way, the range can form a good barrier effect on the metal layer during electroplating, while not being too small to block the electroplated metal ions from entering the via 110, which is beneficial to increase the distribution uniformity of the first metal layer 300 on the inner wall of the via 110.

[0069] Furthermore, since the thickness of the first metal layer 300 is related to the width of the baffle convex ring, the first difference range can form a first metal layer 300 with a certain thickness, so that the conductive performance of the via 110 can be improved.

[0070] In a specific embodiment, the difference between the diameter of the via 110 and the diameter of the first light shielding portion 210 is a first difference, and the first difference may be between 1 mil and 3 mil. In this way, this range can fully form a good blocking effect on the metal layer in the via 110, and at the same time, it matches the height of the size of the via 110, and will not cause the opening of the baffle convex ring to be too small to block the electroplated metal ions from entering the via 110, which is beneficial to increase the distribution uniformity of the first metal layer 300 on the inner side wall of the via 110. Furthermore, the first difference is between 1 mil and 3 mil, which can make the first metal layer 300 thick enough to adapt to resistors with higher power operation requirements, thereby improving the conductive stability of the circuit board. In addition, the range of the first difference will not be too large, which is convenient for subsequent thickening processing of individual vias 110.

[0071] In another specific embodiment, the difference between the diameter of the via hole 110 and the diameter of the first light shielding portion 210 is a first difference, and the first difference may be, but is not limited to, any one of 1 mil, 1.5 mil, 2 mil, 2.5 mil or 3 mil, and is not limited to any one of these. In this way, this range can form a good barrier to the electroplated metal, and will not affect the electroplated metal layer on the inner wall of the via hole 110, which is conducive to increasing the distribution uniformity of the first metal layer 300 on the inner wall of the via hole 110 and ensuring the thickness of the first metal layer 300, and can improve the conductive performance of the via hole 110.

[0072] In combination with any of the above embodiments of the first photosensitive film layer, step S2 further includes:

[0073] like Figures 4 to 5 As shown, the substrate 100 includes a first surface and a second surface disposed opposite to each other along a first direction.

[0074] The first photosensitive film layer 200 is formed on both the first surface and the second surface. The first direction is the arrangement direction of the substrate 100 and the first photosensitive film layer 200. In this way, photosensitive dry film protrusions that limit the movement of the electroplated metal can be formed on both the upper and lower sides of the via hole 110 to block the movement of the electroplated metal, avoid excessive electroplated metal layers on the surface of the circuit board, and improve the adhesion effect of the first metal layer 300 on the inner wall of the via hole 110.

[0075] In some embodiments, the first photosensitive film layer 200 is a dry film that can be dissolved by a specific developer. The dry film is a dry photoresist for transferring images on a circuit board. Generally, the exposed portion of the dry film will be cross-linked, making its structure stronger and less soluble, while the unexposed portion of the dry film can be dissolved by a conventional developer (such as an n-heptane solution or a sodium hydroxide solution, etc.), so the unexposed portion of the dry film is easy to remove.

[0076] Furthermore, the dry film may be made of an organic photosensitive material that can be dissolved in a specific developer, such as polyisoprene. The corresponding specific developer includes xylene or tetramethylammonium hydroxide. During the development process, the xylene or tetramethylammonium hydroxide solution will not damage other structures such as the substrate 100. Of course, the material of the dry film may also be selected from materials such as polycinnamate and polyhydrocarbon.

[0077] In addition, in one embodiment, in addition to the dry film itself, the first photosensitive film layer 200 may also be provided with other sub-film layers, so that the sub-film layers can be peeled off together with the dry film during the exposure and development process. Specifically, the sub-film layer may be a sensitizer or a solvent, and the sub-film layer may be used for exposure of the gain dry film, or for mounting or peeling the gain dry film from the substrate 100, so as to improve processing efficiency.

[0078] In one example, the first photosensitive film layer 200 also includes a separator (such as PE, which can be used for the installation of the gain dry film and the substrate 100) and a protective film (such as PET, which can be used for the exposure of the gain dry film). The separator film and the protective film are arranged on the opposite sides of the dry film along the first direction. In combination with a processing scenario, the separator film layer can be peeled off during the operation, the middle photosensitive resist can be peeled off, and the middle photosensitive resist can be pressed onto the substrate. After exposure, the protective film (such as film, etc.) is torn off, and a local anti-plating resist is formed after washing and development, and then an outer layer of electroplating is formed, and finally the bare metal circuit board is etched and peeled off after the dry film.

[0079] It should be noted that the setting of the first exposure part 220 and the first light-shielding part 210 in the above-mentioned embodiment can be distinguished by the difference in materials or structures themselves, or the first exposure part 220 and the first light-shielding part 210 can be distinguished by local exposure of different areas of the photosensitive film layer of the same material, and no excessive restrictions are made here.

[0080] In some embodiments, Figure 6 As shown, step S2 includes:

[0081] S21 , coating a first dry film layer on the substrate 100 .

[0082] The first dry film layer includes a first light-shielding portion 210 and a first exposure portion 220. The first dry film layer may be a photosensitive liquid material, and the photosensitive liquid material may be applied to the substrate 100 to form the first dry film layer. In this embodiment, the functions of the first exposure portion 220 and the first light-shielding portion 210 are mainly realized by the setting of the light-shielding portion. The light-shielding portion covers the first light-shielding portion 210, so that the dry film layer on the first light-shielding portion 210 is not exposed and then dissolved in the developer. There is no need to select materials for the first dry film layer or perform differentiated processing on the application area, thereby reducing the processing difficulty.

[0083] S22, forming a first light shielding layer on the first dry film layer. That is, a stacked structure of substrate 100, first dry film layer, and first light shielding layer is formed on the first circuit board. The first light shielding layer includes a plurality of light shielding portions arranged at intervals. The light shielding portions are arranged in a one-to-one correspondence with the vias 110.

[0084] The light shielding portion is arranged in one-to-one correspondence with the conducting hole 110. The light shielding portion is arranged to cover the first light shielding portion 210, so that the first light shielding portion 210 is arranged to be light-shielded. That is, the area of ​​the light shielding function on the first light shielding portion 210 can be determined by the size of the light shielding portion.

[0085] The area of ​​the orthographic projection area of ​​the light shielding portion (located at the same position as the first light shielding portion 210) in the first direction is smaller than the area of ​​the orthographic projection area of ​​the hole wall of the via hole 110 in the first direction, and the first direction is the arrangement direction of the substrate 100 and the first photosensitive film layer 200. It can be understood that at least part of the light shielding portion is arranged to cover the first light shielding portion 210, so that the baffle protrusion formed by the first dry film layer can be at least partially present at the periphery of the hole opening of the via hole 110, and based on the fact that the area of ​​the orthographic projection area of ​​the light shielding portion is smaller than the area of ​​the orthographic projection area of ​​the hole wall of the via hole 110, the range of the baffle protrusion is larger. In this way, when the range of the baffle protrusion is larger, even as the metal layer continues to thicken during the electroplating process, the baffle protrusion can resist the first metal layer 300 to prevent the metal layer from overflowing and electroplating to the upper surface of the substrate 100, and ensure that the inner wall of the via hole 110 can form a first metal layer 300 of sufficient thickness, thereby optimizing the metal conductive performance of the via hole 110.

[0086] Further, in combination with any of the above-mentioned embodiments of the first light shielding portion 210, the orthographic projection area of ​​the light shielding portion on the substrate 100 is located inside the orthographic projection area of ​​the hole wall of the via hole 110 on the substrate 100. That is, in this embodiment, the orthographic projection of the first light shielding portion 210 is within the orthographic projection of the via hole 110, so as to realize the formation of the baffle convex ring in the above-mentioned embodiment.

[0087] It should be noted that the first light-shielding layer may be, but is not limited to, a film layer, and may also be other light-shielding materials.

[0088] In addition, in one embodiment, the first light shielding layer further includes a light-transmitting portion arranged around the light shielding portion. The light shielding portion may be one or more, and the number of light shielding portions may be designed according to the number of the vias 110. The light-transmitting portion is arranged corresponding to the first exposure portion 220, so that the first exposure portion 220 is exposed through the light-transmitting portion.

[0089] It can be understood that in this embodiment, the light-transmitting portion and the light-shielding portion in the first light-shielding layer can be connected and matched to form a flat film layer. In the actual installation process of the first light-shielding layer, the first light-shielding layer can be laid and attached to the first dry film layer, so that the through hole 110 corresponds to the light-shielding portion, and other copper foil areas of the substrate 100 can be at least partially covered by the first dry film layer and the first light-shielding layer of the light-shielding portion, so that after the circuit board is exposed and developed, at least part of the other copper foil areas of the substrate 100 can still be covered by the first dry film layer.

[0090] In this way, during the electroplating process, the first dry film layer corresponding to the first exposure part 220 can provide good protection for the copper foil on the substrate 100, preventing the metal layer from adhering to the copper foil and causing damage to the substrate 100, and there is no need to remove the metal layer on the substrate 100, thereby reducing the processing steps and the difficulty of processing.

[0091] In combination with any embodiment of the above-mentioned circuit board manufacturing method, Figure 7 As shown, the circuit board manufacturing method further includes executing the following steps after executing step S4:

[0092] S5, removing the first exposure part 220 to form a second processed substrate. That is, after the electroplating is completed, the first photosensitive dry film on the first exposure part 220 is removed to form a second processed substrate, and the second processed substrate can be used in other processing steps, such as etching, electrical connection, etc.

[0093] Specifically, in one embodiment, Figure 7 The circuit board manufacturing method further includes:

[0094] S61, forming a second photosensitive film layer 400 on a second processed substrate.

[0095] like Figure 8 As shown, the second photosensitive film layer 400 includes a second light shielding portion 410 and a second exposure portion 420 disposed around the second light shielding portion 410. The second light shielding portion 410 is disposed to cover the via 110. The orthographic projection of the second light shielding portion 410 on the substrate 100 is located inside the orthographic projection of the first light shielding portion 210 on the substrate 100.

[0096] Among them, the second photosensitive film layer 400 can be consistent with the type of the first photosensitive film layer 200 in the above embodiment, and can be but not limited to a dry film or a negative photoresist, and the second photosensitive film layer 400 can include multiple sub-film layers, in addition to including a second dry film layer and a second light-shielding layer, it can also include sub-film layers such as solvents and sensitizers.

[0097] S71 , exposing and developing the second photosensitive film layer 400 , retaining the second exposure portion 420 and removing the second light shielding portion 410 , so as to form a third processed substrate.

[0098] It can be understood that, similarly, the second photosensitive film layer 400 on the second light-shielding portion 410 has not been exposed, so the second photosensitive film layer 400 on the second light-shielding portion 410 can be dissolved in the developer. Since the orthographic projection of the second light-shielding portion 410 on the substrate 100 is located inside the orthographic projection of the first light-shielding portion 210 on the substrate 100, there is a non-overlapping position between the first light-shielding portion 210 and the second light-shielding portion 410 (near the periphery of the opening of the through hole 110). After the second exposure and development, the non-overlapping portion forms the second photosensitive film layer 400 that is not dissolved in the developer, and the second photosensitive film layer 400 can be used as a baffle protrusion and arranged at the periphery of the opening of the through hole 110.

[0099] S81 , electroplating the third processed substrate, so that the second metal layer 500 is attached to at least a portion of the hole wall of the through hole 110 , and at least a portion of the second metal layer 500 is stacked with the first metal layer 300 .

[0100] So, like Fig. 9 As shown, the baffle protrusion formed in step S71 can be used to limit the movement of electroplating metal ions during electroplating to prevent the formation of a metal layer on the upper surface of the substrate 100, and can also guide the electroplated metal layer to move along the inner side wall direction of the via 110, so that the second metal layer 500 is at least partially plated on the first metal layer 300, so as to increase the structural thickness of the metal layer on the inner side wall of the via 110.

[0101] It should be noted that the materials of the first metal layer 300 and the second metal layer 500 may be consistent or inconsistent, such as the first metal layer 300 and the second metal layer 500 are both copper layers, or the first metal layer 300 is a copper layer and the second metal layer 500 is a tin layer, etc. Further, when it is necessary to set metal layers of different thicknesses for different vias 110, the size of the second light shielding portion 410 can be differentiated, and the width of the baffle protrusion can be adjusted to achieve different ranges of electroplated metal layer blocking, thereby forming different metal layer thicknesses on different vias 110.

[0102] In another embodiment, if Fig.10 As shown, the circuit board manufacturing method further includes executing the following steps after executing step S5:

[0103] S62, forming a second photosensitive film layer 400 on the second processed substrate. The second photosensitive film layer 400 includes a second dry film layer and a second light shielding layer. The specific steps are as follows.

[0104] S621, forming a second dry film layer on a second processed substrate, wherein the second dry film layer may be made of the same material and structure as the first dry film layer in the above embodiment.

[0105] S622, forming a second light shielding layer on the second dry film layer.

[0106] The second light shielding layer includes a plurality of light shielding patterns and light-transmitting patterns arranged adjacent to the light shielding patterns. Specifically, the second light shielding layer can be a film layer or other light shielding materials. The combination of the light shielding pattern and the light-transmitting pattern can form a circuit pattern, a component pattern, etc.

[0107] S72, exposing and developing the second photosensitive film layer 400, removing the light shielding pattern and the second dry film layer disposed on the light shielding pattern, so as to form a fourth processed substrate. At this time, the second dry film layer disposed on the light-transmitting pattern is retained.

[0108] It is understandable that after the second photosensitive film layer 400 is exposed, the setting of the light-transmitting pattern and the light-shielding pattern forms a certain processing pattern (equivalent to a processing site) on the substrate 100, which facilitates subsequent processing steps such as etching based on this processing site.

[0109] Further, in combination with any embodiment of the fourth processed substrate, the light-transmitting pattern includes a first light-transmitting pattern and a second light-transmitting pattern. The first light-transmitting pattern is used to cooperate with the upper surface of the second processed substrate, so that the first light-transmitting pattern can form a processing site of the outer layer on the second processed substrate. The second light-transmitting pattern is used to cover the setting of the via hole 110, so that the second dry film layer at the position of the via hole 110 will not dissolve in the developer, and then when the fourth processed substrate is subjected to a processing procedure such as etching, the second dry film layer can cover the via hole 110, so that the metal layer in the via hole 110 will not be damaged.

[0110] In addition, in some embodiments, Fig.10 The circuit board manufacturing method further includes:

[0111] S82, etching the fourth processed substrate, wherein the etching type may be acid etching or alkaline etching, which is not limited here.

[0112] Of course, similarly, any processed substrate in the above embodiments can be finally processed through an etching process to form a bare metal circuit board product. Further, any processed substrate 100 in the above embodiments can also be improved by setting other processing steps.

[0113] In one example, in combination with any embodiment of the third processed substrate, the circuit board manufacturing method may further include the following steps:

[0114] After removing the second exposure portion 420 from the third processed substrate, step S72 and step S73 are performed on the third processed substrate. In this way, the third processed substrate can be processed to obtain a circuit board having both the conductive hole 110 thickened by the second metal layer 500 and the processed site.

[0115] Correspondingly, in another example, after removing the light-transmitting pattern and the second dry film layer disposed on the light-transmitting pattern from the fourth processed substrate, step S61, step S71 and step S81 are performed. In this way, the fourth processed substrate can be processed to obtain a circuit board having both the conductive hole 110 thickened by the second metal layer 500 and the processed site.

[0116] The present application also provides an electronic device, including the circuit board in the above embodiment. The electronic device can be, for example, a mobile phone, a tablet computer, or other device with a control effect. Of course, the electronic device also includes components such as a processor, a memory, a power supply component, and a communication component, which will not be described in detail in this embodiment.

[0117] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0118] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0119] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0120] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0121] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0122] The technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above-described embodiments only express several implementation methods of the present application, and the description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the patent application. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several deformations and improvements can be made, which all belong to the scope of protection of the present application. Therefore, the scope of protection of the patent application of this application shall be based on the attached claims.

Claims

1. A method for manufacturing a circuit board, characterized in that: The circuit board manufacturing method comprises: Providing a substrate having a through hole; A first photosensitive film layer is formed on the substrate; the first photosensitive film layer comprises a first light-shielding portion covering the via hole and a first exposure portion arranged around the first light-shielding portion; the first exposure portion partially covers the opening of the via hole; exposing and developing the first photosensitive film layer, retaining the first exposed portion and removing the first light-shielding portion, so as to form a first processed substrate; The first processed substrate is electroplated so that a first metal layer is attached to at least a portion of the hole walls of the via holes.

2. The method for manufacturing a circuit board according to claim 1, characterized in that: The orthographic projection area of ​​the first light shielding portion on the substrate is located within the orthographic projection area of ​​the hole wall of the conducting hole on the substrate.

3. The method for manufacturing a circuit board according to claim 2, characterized in that: A difference between a diameter of the via hole and a diameter of the first light shielding portion is a first difference; the first difference is between 0.5 mil and 3.5 mil.

4. The method for manufacturing a circuit board according to claim 1, characterized in that: The step of forming the first photosensitive film layer on the substrate comprises: The first photosensitive film layer includes a first dry film layer and a first light shielding layer; coating the first dry film layer on the substrate; the first dry film layer comprises the first light-shielding portion and the first exposure portion; The first light shielding layer is formed on the first dry film layer; the first light shielding layer includes a plurality of light shielding portions arranged at intervals; the light shielding portions are arranged corresponding to the through holes one by one; the light shielding portions are arranged to cover the first light shielding portions, so that the first light shielding portions are arranged to be light-proof; The area of ​​the orthographic projection region of the light shielding portion in the first direction is smaller than the area of ​​the orthographic projection region of the hole wall of the via hole in the first direction, and the first direction is the arrangement direction of the substrate and the first photosensitive film layer.

5. The method for manufacturing a circuit board according to claim 4, characterized in that: The first light-shielding layer further includes a light-transmitting portion disposed around the light-shielding portion; the light-transmitting portion is disposed corresponding to the first exposure portion, so that the first exposure portion is exposed through the light-transmitting portion.

6. The method for manufacturing a circuit board according to claim 1, characterized in that: The step of forming a first photosensitive film layer on the substrate includes: The substrate comprises a first surface and a second surface which are arranged opposite to each other along a first direction; the first photosensitive film layer is formed on both the first surface and the second surface; and the first direction is the arrangement direction of the substrate and the first photosensitive film layer.

7. The method for manufacturing a circuit board according to claim 1, characterized in that: The circuit board manufacturing method also includes: After electroplating the first processed substrate, the first exposure portion is removed to form a second processed substrate; forming a second photosensitive film layer on the second processed substrate, wherein the second photosensitive film layer comprises a second light-shielding portion and a second exposure portion disposed around the second light-shielding portion; the second light-shielding portion is disposed to cover the conducting hole; exposing and developing the second photosensitive film layer, retaining the second exposed portion and removing the second light-shielding portion, so as to form a third processed substrate; The third processed substrate is electroplated so that a second metal layer is attached to at least a portion of the hole wall of the through hole, and at least a portion of the second metal layer is stacked with the first metal layer; wherein the orthographic projection of the second light-shielding portion on the substrate is located inside the orthographic projection of the first light-shielding portion on the substrate.

8. The method for manufacturing a circuit board according to claim 1, characterized in that: The circuit board manufacturing method also includes: After electroplating the first processed substrate, the first exposure portion is removed to form a second processed substrate; A second photosensitive film layer is formed on the second processed substrate; the second photosensitive film layer includes a second dry film layer and a second light shielding layer; wherein, forming the second dry film layer on the second processed substrate; forming the second light-shielding layer on the second dry film layer; the second light-shielding layer comprises a plurality of light-shielding patterns and light-transmitting patterns arranged adjacent to the light-shielding patterns; The second photosensitive film layer is exposed and developed to remove the light-shielding pattern and the second dry film layer disposed on the light-shielding pattern, and the second dry film layer disposed on the light-transmitting pattern is retained to form a fourth processed substrate.

9. A circuit board, characterized in that: The circuit board is manufactured by the circuit board manufacturing method as described in any one of claims 1 to 8 above.

10. An electronic device, characterized in that: Comprising the circuit board as claimed in claim 9 above.

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