Circuit board, preparation method of circuit board and electronic equipment

Abstract

The invention provides a circuit board, a preparation method of the circuit board and electronic equipment. The circuit board comprises a substrate; the solder mask layer is arranged on the end face of at least one side of the substrate, and a groove is formed in the end face of the side, away from the substrate, of the solder mask layer; and the reinforcing layer is connected with the side, where the groove is formed, of the solder mask layer, and an adhesive layer is arranged on the reinforcing layer and located in the groove. Through the mode, the adhesive layer can be placed in the groove, so that the adhesive layer is prevented from overflowing from the solder mask layer through the groove, and the edge area, forming the groove, of the solder mask layer is connected with the reinforcing layer, so that the edge area of the reinforcing layer can support the reinforcing layer, and the flatness of the surface of the reinforcing layer is effectively ensured.

Description

Technical Field

[0001] The present application is applied to the technical field of circuit board preparation, and particularly relates to a circuit board, a preparation method thereof, and an electronic device. Background Art

[0002] With the development of technology, the requirements for electronic products are getting higher and higher. Therefore, the requirements for the flatness of circuit boards are also getting higher and higher. For example, with the popularization of multi-functional cameras, it is necessary to ensure the flatness of the camera module. Therefore, it is necessary to ensure the flatness of the circuit board disposed in the camera module. However, when preparing circuit boards in the prior art, the processes of direct lamination and solder mask printing are adopted, which cannot meet the flatness requirements. Although the dry film type solder mask process can meet the flatness requirements, the cost is too high. Summary of the Invention

[0003] The present application provides a circuit board to solve the problem of low flatness of circuit boards in the prior art.

[0004] To solve the above technical problems, on the one hand, the present application provides a circuit board, including: a substrate; a solder mask layer, the solder mask layer is disposed on at least one end face of the substrate, and a groove is formed on the end face of the solder mask layer away from the substrate; a reinforcing layer, the reinforcing layer is connected to the side of the solder mask layer where the groove is formed, and an adhesive layer is disposed on the reinforcing layer, and the adhesive layer is located in the groove.

[0005] Among them, the substrate includes a flexible substrate and a rigid substrate. A prepreg is disposed on a partial area of the flexible substrate, and a conductive layer is disposed on the end face of the prepreg away from the flexible substrate to form a rigid substrate, and the conductive layer is connected to the solder mask layer.

[0006] Among them, a through hole is formed in the area of the solder mask layer located in the groove, so that the adhesive layer is connected to the conductive layer through the through hole. The adhesive layer is a conductive adhesive and is used for grounding.

[0007] Among them, the width of the edge area of the solder mask layer is 0.1 - 0.3 mm.

[0008] To solve the above problems, on the second aspect, the present application also provides a preparation method of a circuit board, including: obtaining a reinforcing layer with an adhesive layer; obtaining a substrate, including a rigid substrate and a flexible substrate; printing solder mask ink on the end face of the rigid substrate to form a solder mask layer with a groove; laminating the reinforcing layer on the solder mask layer to form a circuit board, wherein the adhesive layer is located in the groove, and the remaining part of the solder mask layer is connected to the reinforcing layer.

[0009] Among them, the step of obtaining a substrate, including a rigid substrate and a flexible substrate, includes: obtaining a rigid substrate, and removing the conductive layer and the semi-cured layer on a partial area of the rigid substrate to form a flexible substrate.

[0010] Among them, the steps of printing solder mask ink on the end face of the rigid substrate to form a solder mask layer with grooves include: performing the first printing of solder mask ink on the rigid substrate to form a first solder mask layer on the rigid substrate; performing the second printing of solder mask ink at the edge position of the first solder mask layer to form a second solder mask layer on the first solder mask layer; opening a through hole in the first solder mask layer to expose the conductive layer on the rigid substrate; and removing the excess solder mask ink.

[0011] Among them, laminating a reinforcing layer on the solder mask layer to form a circuit board; among them, after the step that the adhesive layer is located in the groove and the rest of the solder mask layer is connected to the reinforcing layer, it includes: performing a heat treatment on the circuit board to enable the adhesive liquid to be connected to the conductive layer through the through hole.

[0012] Among them, the planar size of the adhesive layer is smaller than that of the reinforcing layer, the adhesive layer is not provided at the edge position of the reinforcing layer, and the edge position of the reinforcing layer is connected to the second solder mask layer.

[0013] To solve the above problems, a third aspect of the present application further provides a method for manufacturing a circuit board, including: a circuit board, and the circuit board is the circuit board of any one of the above.

[0014] The beneficial effect of the present application is: different from the prior art, by forming a solder mask layer with grooves on at least one end face of the substrate, when setting the reinforcing layer on the substrate, the adhesive layer can be placed in the groove, so as to avoid the adhesive layer overflowing from the solder mask layer through the groove, and the edge area of the solder mask layer forming the groove is connected to the reinforcing layer, which can enable the edge area of the reinforcing layer to support the reinforcing layer, thereby effectively ensuring the flatness of the surface of the reinforcing layer. Description of the Drawings

[0015] Figure 1 is a schematic structural diagram of an embodiment of the circuit board of the present application;

[0016] Figure 2 is a schematic structural diagram of the connection between the reinforcing layer and the adhesive layer of the present application;

[0017] Figure 3 is a schematic structural diagram of an embodiment of the solder mask layer of the present application;

[0018] Figure 4 is a schematic structural diagram of the connection between the solder mask layer and the reinforcing layer of the present application;

[0019] Figure 5 is a schematic flow chart of an embodiment of the method for manufacturing the circuit board of the present application;

[0020] Figure 6 is the present application Figure 5 a schematic flow chart of an embodiment of S13 therein. Detailed Embodiments

[0021] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0022] It should be noted that if there are directional indications (such as up, down, left, right, front, back,...) involved in the embodiments of the present application, then the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0023] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, then the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0024] Please refer to Figure 1 , Figure 1 which is a structural block diagram of an embodiment of the circuit board provided by the present application.

[0025] The present application provides a circuit board. As Figure 1 shown, a circuit board in this embodiment includes a substrate 10, a solder mask layer 20, and a reinforcing layer 30. As combined with Figure 3 shown, the solder mask layer 20 is disposed on at least one end surface of the substrate 10. A groove 203 is formed on the end surface of the solder mask layer 20 away from the substrate 10. The reinforcing layer 30 is connected to the side of the solder mask layer 20 where the groove 203 is formed. An adhesive layer 301 is disposed on the reinforcing layer 30, and the adhesive layer 301 is located in the groove 203. Among them, the reinforcing layer 30 can be a steel sheet, which can support the circuit board on the one hand. When the circuit board is installed on an electronic device, the flatness of the circuit board can be ensured. For example, when the circuit board is installed in a camera, the flatness of components such as lenses in the camera can be effectively ensured. In other embodiments, it can also be set in other electronic devices, and the present application does not make specific limitations here.

[0026] In an alternative embodiment, solder mask layers 20 are formed on both side end faces of the substrate 10. That is, after the substrate 10 is prepared and formed, a solder mask ink layer is prepared and formed on at least one side end face of the substrate 10. For example, a solder mask ink layer is printed or roll-coated on one side end face of the circuit board. After the solder mask ink layer is formed on the substrate 10, the solder mask ink layer is subjected to an exposure process. For example, the solder mask ink layer is irradiated with UV (ultraviolet) light to perform an exposure process on the solder mask ink layer. It can be understood that when the solder mask ink is irradiated with ultraviolet light, the corresponding resin monomers thereof will generate free radical impacts and break the double bonds to generate a polymerization cross-linking reaction, thereby forming the solder mask layer 20 on the substrate 10.

[0027] Wherein, after the solder mask layer 20 is prepared, printing or coating of the solder mask ink and the exposure process can be performed on the solder mask layer 20 for the second time. The specific method is the same as the above scheme and will not be elaborated here too much. A solder mask ink layer is prepared and formed on the solder mask layer 20 for the second time, thereby forming a solder mask layer 20 with a groove 203 on one side end face of the substrate 10.

[0028] Combined with Figure 2 As shown, after the solder mask layer 20 with a groove 203 is formed on the substrate 10, the reinforcing layer 30 can be connected to the side with the groove 203 formed. An adhesive layer 301 is formed on one side end face of the reinforcing layer 30. When the reinforcing layer 30 is disposed on the solder mask layer 20, the adhesive layer 301 can be fixed inside the groove 203. Among them, the adhesive layer 301 is disposed in a partial area of the reinforcing layer 30. For example, the adhesive layer 301 is not disposed in the edge area of the reinforcing layer 30, and the adhesive layer 301 is located in the middle area of the reinforcing layer 30.

[0029] In this embodiment, as Figure 4 shown, when the reinforcing layer 30 is installed on the solder mask layer 20, the adhesive layer 301 is placed inside the groove 203, and the edge area of the solder mask layer 20 is connected to the reinforcing layer 30. That is, the solder mask layer 20 can wrap the adhesive layer 301 on the reinforcing layer 30 to prevent the adhesive liquid from overflowing in the subsequent process. Moreover, the solder mask layer 20 with a groove 203 is provided on the substrate 10, and the edge area of the solder mask layer 20 is connected to the reinforcing layer 30, which can support the edge area of the reinforcing layer 30, thereby effectively ensuring the flatness of the end face of the reinforcing layer 30 on the side away from the adhesive layer 301. That is, the solder mask layer 20 and the reinforcing layer 30 are provided on the substrate 10 to form a circuit board, which can effectively ensure the flatness of the surface of the circuit board. When the circuit board is installed in an electronic device, such as in a camera, the flatness of the lenses in the camera can be effectively ensured.

[0030] In the above - mentioned manner, by forming a solder mask layer 20 with grooves 203 on at least one end face of the substrate 10, when the reinforcing layer 30 is disposed on the substrate 10, the adhesive layer 301 can be placed in the grooves 203, thereby avoiding the overflow of the adhesive layer 301 from within the solder mask layer 20 through the grooves 203. Moreover, the edge region of the solder mask layer 20 where the grooves 203 are formed is connected to the reinforcing layer 30, enabling the edge region of the reinforcing layer 30 to support the reinforcing layer 30, thereby effectively ensuring the flatness of the surface of the reinforcing layer 30.

[0031] In an alternative embodiment, as Figure 1 shown, the substrate 10 includes a flexible substrate 102 and a rigid substrate 101. A prepreg is disposed on a partial region of the flexible substrate 102, and a conductive layer 50 is disposed on one end face of the prepreg away from the flexible substrate 102 to form the rigid substrate 101, and the conductive layer 50 is connected to the solder mask layer 20. That is, a prepreg is formed on the flexible substrate 102 to support the flexible substrate 102, that is, the substrate 10 is supported by the prepreg. When the prepreg is formed on the flexible substrate 102, a conductive layer 50 is formed on one end face of the prepreg away from the flexible substrate 102, thereby forming the rigid substrate 101.

[0032] In this embodiment, the rigid substrate 101 can be prepared first, that is, the inner layer of the rigid substrate 101 wraps the flexible board, prepregs are formed on both end faces of the flexible board, and conductive layers 50 are formed on both end faces of the prepregs, thereby forming the rigid substrate 101. After the rigid substrate 101 is formed, the conductive layer 50 and the semi - cured layer 40 on a partial region of the rigid substrate 101 can be removed by laser cutting or mechanical cutting, thereby forming the flexible substrate 102 on one side of the rigid substrate 101. That is, when the substrate 10 is installed in an electronic device, the rigid substrate 101 can support electronic components, and the flexible substrate 102 can reduce the layout pressure of the substrate 10 when the substrate 10 is installed in the electronic device. After the rigid substrate 101 is formed, the solder mask layer 20 can be printed or coated on the rigid substrate 101, and the reinforcing layer 30 is formed on the solder mask layer 20 to ensure the flatness of the rigid substrate 101.

[0033] In an alternative embodiment, through - holes (not shown in the figure) are formed in the region of the solder mask layer 20 where the grooves 203 are located, so that the adhesive layer 301 is connected to the conductive layer 50 through the through - holes. The adhesive layer 301 is a conductive adhesive for grounding. After the rigid substrate 101 is prepared, that is, a conductive layer 50 is formed on one end face of the prepreg of the rigid substrate 101. Among them, the conductive layer 50 can be formed of a metallic conductive material, thereby forming a conductive metal part. For example, a copper foil or other metallic sheet can be disposed on the surface of the semi - cured material to form the conductive layer 50.

[0034] Among them, the substrate 10 needs to be grounded. Therefore, when forming the solder mask layer 20 on the rigid substrate 101, the solder mask layer 20 needs to be opened, so as to form a through hole in the groove 203 area of the solder mask layer 20, so that the adhesive layer 301 passes through the through hole and is connected to the conductive layer 50. Since the conductive layer 50 is grounded and the adhesive layer 301 is a conductive adhesive, the adhesive layer 301 and the conductive layer 50 are connected through the through hole, so that the substrate 10 is connected to the ground.

[0035] The width of the edge area of the solder mask layer 20 is 0.1-0.3 mm. That is, the width of the part of the groove 203 formed in the edge area of the solder mask layer 20 is 0.1-0.3 mm, which can be any reasonable value, such as 0.15 mm, 0.2 mm, etc. Specifically, it can be limited according to the area of the reinforcing layer 30 where the adhesive layer 301 is not provided. The present application does not make specific limitations here. It should be noted that the width of the edge area of the solder mask layer 20 is not less than the width of the area of the reinforcing layer 30 where the adhesive layer 301 is not provided. The solder mask layer 20 exceeding the area of the reinforcing layer 30 where the adhesive layer 301 is not provided can be removed in the subsequent process, so as to ensure the flatness of the side area of the substrate 10.

[0036] In this embodiment, after forming the conductive layer 50 on the surface of the semi-cured layer 40 and preparing its circuit, that is, when forming the solder mask layer 20 on the rigid substrate 101, it is necessary to insulate the areas that do not need to be welded or connected to other devices in the subsequent process. That is, through holes are opened in the areas where the conductive layer 50 needs to be connected to the adhesive layer 301, and the solder mask layer 20 is set in the areas that do not need to be connected to the adhesive layer 301. When setting the solder mask layer 20 on the conductive layer 50, a solder mask ink layer can be first formed on the end face of the conductive layer 50. After forming the solder mask ink layer, a light-shielding film can be set in the area where window opening is required, and then the solder mask ink layer is exposed. When exposing the solder mask ink layer, a polymerization cross-linking reaction will occur in the area where the light-shielding film is not set, so as to polymerize and harden to form a high-molecular polymer that is not easily soluble in the developing solution. And because the area where the solder mask ink layer needs to be opened is blocked by the light-shielding film during the exposure process, the polymerization cross-linking reaction in this area can be avoided. That is, the area where window opening is required can be dissolved in the developing solution in the subsequent process. After the exposure is completed, the light-shielding film can be removed. After removing the light-shielding film, the substrate 10 is placed in the developing solution to dissolve the solder mask ink layer in the area blocked by the light-shielding film, so as to remove the solder mask ink in the area blocked by the light-shielding film and expose the conductive layer 50 on one end face of the substrate 10, so as to facilitate the subsequent adhesive liquid to be connected to the conductive layer 50 through the through hole, so that the substrate 10 is grounded. Among them, the set position of the light-shielding film corresponds to the position that needs to be connected to the conductive layer 50 in the subsequent process, and it can be reasonably set by the user. The present application does not make limitations on this.

[0037] Please refer to Figure 5 , Figure 5It is a schematic flowchart of an embodiment of the method for preparing a circuit board of the present application. It should be noted that if there are substantially the same results, the method of the present invention is not limited to Figure 5 the process sequence shown. For example, Figure 5 as shown, the method includes the following steps:

[0038] S11: Obtain a reinforcing layer 30 with an adhesive layer 301.

[0039] In this embodiment, a reinforcing layer 30 with an adhesive layer 301 can be obtained. The adhesive layer 301 is located on the surface of one side of the reinforcing layer 30. First, the reinforcing layer 30 can be obtained, and then the adhesive layer 301 can be coated or printed on one end face of the reinforcing layer 30. Among them, the adhesive layer 301 is located in the central area of the reinforcing layer 30, that is, the edge area of the reinforcing layer 30 is not provided with the adhesive layer 301. The adhesive layer 301 is a conductive adhesive and is used to connect to the ground after being subsequently disposed on the substrate 10.

[0040] S12: Obtain a substrate 10, including a rigid substrate 101 and a flexible substrate 102.

[0041] Specifically, first, the substrate 10 can be laminated. The substrate 10 is a multilayer board, the middle layer is a flexible board, a semi-cured layer 40 is provided on the outer side of the flexible board, and a conductive layer 50 is provided on one end face of the semi-cured layer 40 away from the flexible board, thereby forming a rigid substrate 101. That is, the rigid substrate 101 at least sequentially includes: a conductive layer 50, a semi-cured layer 40, a flexible board, a semi-cured layer 40, and a conductive layer 50.

[0042] Among them, after the rigid substrate 101 and the flexible substrate 102 are formed, the conductive layer 50 on the end face of the rigid substrate 101 can be patterned to form a conductive circuit layer on the rigid substrate 101.

[0043] S13: Prepare solder resist ink on the end face of the rigid substrate 101 to form a solder resist layer 20 with a groove 203.

[0044] Furthermore, solder resist ink is printed on at least one side end face of the rigid substrate 101, thereby forming a solder resist layer 20 with a groove 203, so as to facilitate subsequent lamination of the reinforcing layer 30 on the solder resist layer 20 and lamination of the adhesive layer 301 in the groove 203. The groove 203 can effectively prevent the adhesive layer 301 from overflowing after softening in subsequent processes, thereby causing poor contact between the circuit board and the ground.

[0045] Among them, before performing solder mask treatment on the rigid substrate 101, it is necessary to first perform pre-treatment before solder mask on the rigid substrate 101. For example, clean the end face of the rigid substrate 101 to remove debris on the end face of the rigid substrate 101, and prevent the bonding force between the rigid substrate 101 and the solder mask ink from being insufficient when preparing the solder mask layer 20 on the end face of the rigid substrate 101 subsequently.

[0046] After cleaning the rigid substrate 101, solder mask ink can be prepared on both end faces of the rigid substrate 101 to form a solder mask. Specifically, on one end face of the rigid substrate 101, a solder mask layer 20 with grooves 203 can be formed through multiple printings for subsequent connection with the reinforcing layer 30, and on the other end face, only solder mask ink is printed once to form a solder mask. In other embodiments, if it is necessary to provide reinforcing plates on both end faces of the rigid substrate 101, solder mask ink can also be printed multiple times on both end faces of the rigid substrate 101 to form a solder mask layer 20 for connecting the reinforcing layer 30, which can be specifically set according to requirements, and the present application does not make specific limitations here.

[0047] S14: Press the reinforcing layer 30 onto the solder mask layer 20 to form a circuit board, where the adhesive layer 301 is located in the groove 203, and the rest of the solder mask layer 20 is connected to the reinforcing layer 30.

[0048] Furthermore, after forming the solder mask layer 20 with grooves 203 on the rigid substrate 101, the end face of the reinforcing layer 30 with the adhesive layer 301 is oriented towards the solder mask layer 20 and laminated on the solder mask layer 20. That is, during lamination, the edge region of the solder mask layer 20 is connected to the reinforcing layer 30, and the adhesive layer 301 is laminated inside the groove 203 to form a circuit board. Since the solder mask layer 20 is formed with grooves 203, the adhesive layer 301 can be blocked by the solder mask layer 20 to avoid the occurrence of glue overflow, resulting in poor contact of the circuit board. Among them, after the adhesive layer 301 is laminated in the groove 203, the adhesive layer 301 will flow into the conductive layer 50 through the through holes on the solder mask layer 20, so that the adhesive layer 301 is connected to the conductive layer 50 to facilitate grounding of the circuit board.

[0049] In this embodiment, since the adhesive layer 301 is not provided in the edge region of the reinforcing layer 30, when the reinforcing layer 30 is laminated on the solder mask layer 20, the edge region of the solder mask layer 20 will be connected to the edge region of the reinforcing layer 30, so that the edge region of the groove 203 formed by the solder mask layer 20 supports the reinforcing layer 30, effectively avoiding the occurrence of indentation and other situations in the edge region of the reinforcing layer 30, which may lead to a decrease in the flatness of the circuit board.

[0050] Specifically, the above S12 may further include the following steps:

[0051] S121: Obtain the rigid substrate 101, and remove the conductive layer 50 and the semi-cured layer 40 on a partial area of the rigid substrate 101 to form the flexible substrate 102.

[0052] After forming the rigid substrate 101, it can be cut in the area that needs to be bent during subsequent assembly in the electronic device. For example, by using laser cutting or mechanical cutting, etc., the conductive layer 50 and the semi-cured layer 40 on the area that needs to be bent are removed, so that only the flexible board is left to form the flexible substrate. That is, the substrate 10 includes the rigid substrate 101 and the flexible substrate connected to the rigid substrate 101.

[0053] Please refer to Figure 6 , Figure 6 Yes Figure 5 is a schematic flowchart of an embodiment of S13 in

[0054] S131: Perform the first printing of solder resist ink on the rigid substrate 101 to form the first solder resist layer 201 on the rigid substrate 101.

[0055] In an optional embodiment, after preparing and forming the conductive layer 50 on the rigid substrate 101 and completing the circuit preparation, print or coat the solder resist ink on at least one end face of the rigid substrate 101. After preparing the solder resist ink on the rigid substrate 101, perform an exposure treatment on the solder resist ink through ultraviolet light, so that the solder resist ink undergoes a polymerization cross-linking reaction, thereby forming the first solder resist layer 201 on the rigid substrate 101. Among them, the thickness of the first solder resist layer 201 is 15um - 23um, which can be specifically set according to requirements, and the present application does not make specific limitations here.

[0056] Among them, the solder resist ink can be printed on both end faces of the rigid substrate 101, so as to form the first solder resist layer 201 on both end faces of the rigid substrate 101.

[0057] S132: Perform the second printing of solder resist ink at the edge position of the first solder resist layer 201 to form the second solder resist layer 202 on the first solder resist layer 201.

[0058] Further, after the first solder mask layer 201 is formed on the rigid substrate 101, a second solder mask layer 202 can be prepared on the first solder mask layer 201 on at least one end face of the rigid substrate 101. The second solder mask layer 202 is printed on the edge area of the first solder mask layer 201 and is subjected to processes such as exposure. Specifically, it is the same as the above-described method for preparing the solder mask layer 20, and the present application does not make specific limitations here. By preparing the second solder mask layer 202 on the first solder mask layer 201, and the second solder mask layer 202 is located at the edge position of the first solder mask layer 201, a raised second solder mask layer 202 is formed at the edge position of the first solder mask layer, etc. When laminating the reinforcing layer 30, the second solder mask layer 202 can be used to block the adhesive layer 301. The planar size of the adhesive layer 301 is smaller than the planar size of the reinforcing layer 30, and the adhesive layer 301 is not provided at the edge position of the reinforcing layer 30. The edge position of the reinforcing layer 30 is connected to the second solder mask layer 202, thereby supporting the reinforcing layer 30. Among them, the thickness of the second solder mask layer 202 is 20um - 28um, and the width is 0.1 - 0.3mm. Specifically, it can be set according to requirements, and the present application does not make specific limitations here. Among them.

[0059] S133: Open a through hole in the first solder mask layer 201 to expose the conductive layer 50 on the rigid substrate 101.

[0060] In this embodiment, after the second solder mask layer 202 is formed on the first solder mask layer 201, the first solder mask layer 201 in the area that needs to be connected to the conductive layer 50 can be removed by mechanical cutting or laser cutting, so as to expose the conductive layer 50 on the rigid substrate 101, which is convenient for the adhesive layer 301 to pass through the through hole and connect to the conductive layer 50 when connecting the reinforcing layer 30 subsequently.

[0061] In other embodiments, it is also possible to prepare the solder mask layer 20 for the first time by setting a light-blocking film and developing at the position where the through hole needs to be opened. Specifically, it is the same as the above-described method for preparing the solder mask layer 20, and details are not elaborated here.

[0062] S134: Remove the excess solder mask ink.

[0063] In this embodiment, when preparing the first solder mask layer 201 and the second solder mask layer 202, in order to avoid that some areas of the reinforcing layer 30 cannot be connected to the second solder mask layer 202, therefore, the planar size of the first solder mask layer 201 needs to be larger than the planar size of the reinforcing layer 30. After laminating the reinforcing layer 30, the solder mask layer 20 that exceeds the side surface of the reinforcing layer 30 is removed to avoid the solder mask layer 20 that exceeds the part from affecting the performance of the circuit board.

[0064] Further, the above S14 can specifically further include the following steps.

[0065] S141: Heat-treat the circuit board so that the adhesive passes through the through-hole to connect with the conductive layer 50.

[0066] In this embodiment, after laminating the reinforcing layer 30 on the solder resist layer 20, the circuit board as a whole can be heat-treated, such as baking, so that the adhesive layer 301 melts. The melted adhesive layer 301 will flow through the through-hole and onto the conductive layer 50, so that the adhesive layer 301 is connected to the conductive layer 50 to facilitate grounding of the circuit board.

[0067] Based on the overall inventive concept, the present application also provides an electronic device, including a circuit board obtained by the preparation method of the circuit board described in any one of the above.

[0068] The above is only the implementation manner of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present application by the same token.

Claims

1. A circuit board, characterized in that, The circuit board includes: A substrate; A solder mask layer disposed on at least one end face of the substrate, and a groove is formed on the end face of the solder mask layer away from the substrate; A reinforcing layer connected to the side of the solder mask layer where the groove is formed, and an adhesive layer is provided on the reinforcing layer, and the adhesive layer is located in the groove.

2. The circuit board according to claim 1, wherein The substrate includes a flexible substrate and a rigid substrate. A prepreg is provided on a partial area of the flexible substrate, and a conductive layer is provided on the end face of the prepreg away from the flexible substrate to form the rigid substrate, and the conductive layer is connected to the solder mask layer.

3. The circuit board according to claim 2, wherein A through hole is formed in the area of the solder mask layer located in the groove, so that the adhesive layer is connected to the conductive layer through the through hole, and the adhesive layer is a conductive adhesive for grounding.

4. The circuit board according to claim 1, wherein The width of the edge area of the solder mask layer is 0.1 - 0.3 mm.

5. A method for preparing a circuit board, characterized in that, The method for manufacturing the circuit board includes: Obtaining a reinforcing layer with an adhesive layer; Obtaining a substrate, including a rigid substrate and a flexible substrate; Printing solder mask ink on the end face of the rigid substrate to form a solder mask layer with a groove; Pressing the reinforcing layer onto the solder mask layer to form the circuit board; wherein, the adhesive layer is located in the groove, and the rest of the solder mask layer is connected to the reinforcing layer.

6. The manufacturing method of the circuit board according to claim 5, characterized in that, The step of obtaining the substrate, including a rigid substrate and a flexible substrate, includes: Obtaining a rigid substrate, and removing the conductive layer and the semi-cured layer on a partial area of the rigid substrate to form the flexible substrate.

7. The method for preparing a circuit board according to claim 5, wherein The step of printing solder mask ink on the end face of the rigid substrate to form a solder mask layer with a groove includes: Performing a first printing of solder mask ink on the rigid substrate to form a first solder mask layer on the rigid substrate; Performing a second printing of solder mask ink at the edge position of the first solder mask layer to form a second solder mask layer on the first solder mask layer; Opening a through hole in the first solder mask layer to expose the conductive layer on the rigid substrate; Removing the excess solder mask ink.

8. The method for preparing a circuit board according to claim 7, wherein, After the step of pressing the reinforcing layer onto the solder mask layer to form the circuit board; wherein, the adhesive layer is located in the groove, and the rest of the solder mask layer is connected to the reinforcing layer, the following steps are included: Performing a heat treatment on the circuit board to enable the adhesive liquid to be connected to the conductive layer through the through hole.

9. The method for preparing a circuit board according to claim 7, wherein The planar dimension of the adhesive layer is smaller than the planar dimension of the reinforcing layer, the adhesive layer is not provided at the edge position of the reinforcing layer, and the edge position of the reinforcing layer is connected to the second solder mask layer.

10. An electronic device, characterized in that, The electronic device includes the circuit board according to any one of claims 1 - 4.

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