Embedded PCB and manufacturing method thereof

Abstract

The invention relates to the technical field of printed circuit board manufacturing, and discloses an embedded PCB and a manufacturing method thereof.The manufacturing method of the embedded PCB comprises the steps that an embedded layer, a first bonding layer and a first adding layer are stacked in sequence, the embedded layer is provided with embedded grooves and stress grooves, the embedded grooves and the stress grooves are arranged at intervals, embedded blocks are arranged in the embedded grooves, and the stress grooves are arranged in the embedded blocks; the thermal expansion coefficient of the embedded layer is larger than that of the embedded block, and the stress groove penetrates through the embedded layer in the arrangement direction of the embedded layer and the first adding layer; and laminating the embedded layer, the first bonding layer and the first adding layer, wherein a gap between the inner wall of the embedded groove and the embedded block is filled with part of the first bonding layer. The embedded PCB and the manufacturing method thereof provided by the invention are used for solving the problems that the position of the ceramic block is easy to deviate and the board is warped in the process of manufacturing the embedded PCB in the prior art.

Description

Technical Field

[0001] This application relates to the field of printed circuit board manufacturing technology, specifically to an embedded PCB and its manufacturing method. Background Technology

[0002] Embedded PCB (Printed Circuit Board) refers to a special type of PCB product in which components, conductors or other functional structures are pre-embedded or embedded in the PCB during the manufacturing process, rather than being made using traditional surface mount or through-hole mounting processes.

[0003] In recent years, embedding high thermal conductivity and low CTE (Coefficient of thermal expansion) materials such as metal blocks and ceramic blocks into PCBs to achieve better thermal management and improve product reliability has become a popular technology. However, in the manufacturing process of such embedded PCBs, it has been found that when the embedded blocks are laminated together with other layers to form a multilayer board, the embedded blocks may shift in position relative to the preset embedding area, affecting the accuracy of subsequent drilling. At the same time, a "bowing" phenomenon, also known as board warping, may occur, affecting subsequent processes such as drilling.

[0004] Therefore, existing methods for manufacturing embedded PCBs need to be improved. Summary of the Invention

[0005] This application provides an embedded PCB and its manufacturing method to solve the problems of ceramic block displacement and board warping that easily occur during the manufacturing process of embedded PCBs in the prior art.

[0006] In a first aspect, embodiments of this application provide a method for manufacturing an embedded PCB, including:

[0007] The embedded layer, the first adhesive layer and the first reinforcement layer are stacked in sequence. The embedded layer is provided with an embedded groove and a stress groove. The embedded groove and the stress groove are arranged at intervals. An embedded block is provided in the embedded groove. The thermal expansion coefficient of the embedded layer is greater than the thermal expansion coefficient of the embedded block. The stress groove penetrates the embedded layer along the arrangement direction of the embedded layer and the first reinforcement layer.

[0008] The embedded layer, the first adhesive layer, and the first reinforcement layer are pressed together, and part of the first adhesive layer fills the gap between the inner wall of the embedded groove and the embedded block.

[0009] In some embodiments, the embedded groove is positioned parallel to and opposite to the stress groove on the side closest to it.

[0010] In some embodiments, multiple stress grooves are provided, and the multiple stress grooves are spaced apart around the embedded groove.

[0011] In some embodiments, multiple embedded grooves are provided, and the multiple embedded grooves are spaced apart, with one embedded groove corresponding to multiple stress grooves.

[0012] In some embodiments, the stress groove is provided between two adjacent embedded grooves.

[0013] In some embodiments, the first adhesive layer shields the stress groove; during the pressing process of the embedded layer, the first adhesive layer and the first reinforcement layer, a portion of the first adhesive layer fills the stress groove.

[0014] In some embodiments, the side of the stress groove facing the groove opening of the first adhesive layer is chamfered.

[0015] In some embodiments, one of the inner wall of the embedding groove and the embedding block is provided with a protrusion, and the other of the inner wall of the embedding groove and the embedding block abuts against the protrusion.

[0016] In some embodiments, a plurality of protrusions are provided, and the plurality of protrusions are spaced apart around the axis of the embedded groove.

[0017] Secondly, embodiments of this application provide an embedded PCB, which is manufactured by the embedded PCB manufacturing method described in the first aspect.

[0018] The embedded PCB manufacturing method provided in this application has the following advantages: Since the embedded layer is provided with embedded grooves and stress grooves, and the embedded grooves and stress grooves are spaced apart, and embedded blocks are provided in the embedded grooves, and the stress grooves penetrate the embedded layer along the arrangement direction of the embedded layer and the first additive layer, when the embedded layer, the first adhesive layer and the first additive layer are pressed together, the embedded blocks are not affected by the stress generated by the embedded layer or are less affected by the stress generated by the embedded layer, thereby improving the embedded block position displacement and the "bowing" problem in the area where the embedded block is located.

[0019] The advantages of the embedded PCB provided in this application compared to the prior art can be found in the description of the advantages of the embedded PCB manufacturing method provided in this application compared to the prior art, which will not be repeated here. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of a method for manufacturing an embedded PCB in one embodiment of this application;

[0022] Figure 2 This is a schematic diagram of the embedded layer, the first adhesive layer and the first reinforcement layer being stacked sequentially in one embodiment of this application;

[0023] Figure 3 yes Figure 2 The top view of the embedded layer shown;

[0024] Figure 4 Yes Figure 2 A schematic diagram showing the lamination process of the embedded layer, the first adhesive layer, and the first add-in layer;

[0025] Figure 5 This is a schematic diagram of the stress groove structure of the embedded layer in one embodiment of this application;

[0026] Figure 6 This is a top view of the embedded layer in another embodiment of this application;

[0027] Figure 7 This is a schematic diagram of the embedded groove and embedded block of the embedded layer in one embodiment of this application.

[0028] The markings in the diagram mean:

[0029] 10. Embedded layer; 11. Embedded groove; 12. Stress groove; 121. Chamfer; 13. Protrusion;

[0030] 20. First adhesive layer;

[0031] 30. First additional layer;

[0032] 40. Embedded block;

[0033] 50. Second adhesive layer;

[0034] 60. Second layer added. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0036] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0038] In this specification, references to "one embodiment," "some embodiments," or simply "embodiment" mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. Furthermore, in one or more embodiments, specific features, structures, or characteristics may be combined in any suitable manner.

[0039] Embedded PCBs refer to a special type of PCB product in which components, conductors, or other functional structures are pre-embedded or embedded within the PCB during the PCB manufacturing process, rather than being made using traditional surface mount or through-hole mounting processes.

[0040] In recent years, embedding high thermal conductivity and low CTE materials such as metal blocks and ceramic blocks into PCBs to achieve better thermal management and improve product reliability has become a popular technology. However, in the manufacturing process of such embedded PCBs, it has been found that when the embedded blocks are laminated together with other layers to form a multilayer board, due to the large difference in thermal expansion coefficients between the embedded layers and the embedded blocks, both undergo a heating stage and a cooling stage during the lamination process. The deformation of the embedded layers caused by temperature is much greater than that of the embedded blocks. This causes the embedded blocks to be affected by the stress of the surrounding embedded layers (compressive stress during the heating stage and tensile stress during the cooling stage), making them prone to positional deviation relative to the preset embedding area. This affects the subsequent drilling accuracy and may also produce a "bowing" phenomenon, also known as board warping, which affects the accuracy of subsequent processes such as drilling and PCB wiring.

[0041] Therefore, existing methods for manufacturing embedded PCBs need to be improved.

[0042] In view of this, this application provides an embedded PCB and its manufacturing method. Since the embedded layer is provided with embedded grooves and stress grooves, and the embedded grooves and stress grooves are arranged at intervals, and embedded blocks are provided in the embedded grooves, and the stress grooves penetrate the embedded layer along the arrangement direction of the embedded layer and the first additive layer, when the embedded layer, the first adhesive layer and the first additive layer are pressed together, the embedded blocks are not affected by the stress generated by the embedded layer or are less affected by the stress generated by the embedded layer, thereby improving the embedded block position displacement and the "bowing" problem in the area where the embedded block is located.

[0043] To illustrate the technical solution of this application, the following description is provided in conjunction with specific accompanying drawings and embodiments.

[0044] Please refer to Figures 1 to 4 In a first aspect, embodiments of this application provide a method for manufacturing an embedded PCB, comprising:

[0045] S100: The embedded layer 10, the first adhesive layer 20 and the first reinforcement layer 30 are stacked in sequence. The embedded layer 10 is provided with an embedded groove 11 and a stress groove 12. The embedded groove 11 and the stress groove 12 are spaced apart. An embedded block 40 is provided in the embedded groove 11. The thermal expansion coefficient of the embedded layer 10 is greater than that of the embedded block 40. The stress groove 12 penetrates the embedded layer 10 along the arrangement direction of the embedded layer 10 and the first reinforcement layer 30.

[0046] The embedded layer 10 can be a single-sided copper-clad board or a double-sided copper-clad board (i.e., circuit patterns can be laid on one or both sides), or it can be a multi-layer core board formed by at least one lamination process, or it can be a double-sided copper-free board (i.e., only an insulating dielectric layer).

[0047] The first adhesive layer 20 can be a semi-cured sheet, comprising resin and fiberglass cloth. Before pressing, it is in a semi-cured state. During pressing, the resin is affected by temperature and pressure, transforming into a molten flow state to fill the gap between the embedded layer 10 and the first reinforcement layer 30 on both sides, thus bonding them together. After pressing, it transforms into a cured state. Commonly used resin materials include epoxy resin, polytetrafluoroethylene resin, polyphenylene ether resin, polyimide resin, and bismaleimide triazine resin.

[0048] The first additional layer 30 can be a single-sided copper-clad board, a double-sided copper-clad board, or a multi-layer core board, or it can be copper foil, etc.

[0049] The embedded groove 11 can penetrate the embedded layer 10. The shape of the embedded groove 11 matches the shape of the embedded block 40, and its size is slightly larger than that of the embedded block 40. The embedded groove 11 can be manufactured by mechanical milling or laser cutting, with mechanical milling being more efficient. Multiple embedded grooves 11 and embedded blocks 40 can be provided, and they are configured in a one-to-one correspondence.

[0050] The stress groove 12 is manufactured using traditional machining or laser processing methods, such as machine milling and laser cutting. One or more stress grooves 12 can be provided, and they can be located in the non-circuit area of ​​the embedded layer 10. The stress groove 12 can be positioned opposite to the embedded slot 11. The distance between the stress groove 12 and the embedded slot 11 can be determined according to the size of the embedded layer 10 and the PCB size, such as 5mm, 8mm, or 10mm, or other distances.

[0051] The embedded block 40 can be a ceramic block, and its material can be silicon nitride ceramic, aluminum nitride ceramic, or alumina ceramic, etc.; the embedded block 40 can also be a metal block, such as a copper block or an aluminum block. Pre-drilled holes can be provided on the embedded block 40.

[0052] It is understandable that before the embedded layer 10, the first adhesive layer 20 and the first reinforcement layer 30 are stacked in sequence, the embedded layer 10 and the first reinforcement layer 30 can be used to create inner layer circuits and complete relevant inspections and tests according to processes such as film application, exposure and development.

[0053] S200: The embedded layer 10, the first adhesive layer 20 and the first reinforcement layer 30 are pressed together, and part of the first adhesive layer 20 fills the gap between the inner wall of the embedded groove 11 and the embedded block 40.

[0054] During the pressing process of embedding layer 10, first adhesive layer 20 and first reinforcement layer 30, the resin in the first adhesive layer 20 is affected by temperature and pressure to change the dynamic state of melting flow to fill the gap between the inner wall of embedding groove 11 and embedding block 40 and to bond embedding layer 10, embedding block 40 and first reinforcement layer 30 together. After pressing, it becomes a solidified state.

[0055] If the stress groove 12 is not provided, during the pressing process of the embedded layer 10, the first adhesive layer 20 and the first reinforcement layer 30, both the embedded layer 10 and the embedded block 40 undergo a heating stage followed by a cooling stage. Since the thermal expansion coefficient of the embedded layer 10 is greater than that of the embedded block 40, the deformation of the embedded layer 10 caused by temperature is much greater than that of the embedded block 40. As a result, the embedded block 40 is easily affected by the stress of the surrounding embedded layer 10 (compressive stress during the heating stage and tensile stress during the cooling stage), which can easily cause positional displacement and affect the subsequent drilling accuracy. At the same time, the area where the embedded block 40 is located may experience a "bowing" phenomenon, also known as board warping, which affects the accuracy of subsequent processes such as drilling and wiring.

[0056] For example, when the embedded layer 10 is FR-4 and the embedded block 40 is a ceramic block, the coefficient of thermal expansion of the ceramic is only 1 / 2 to 1 / 3 of that of FR-4, and the elastic modulus is 12 to 27 times that of FR-4. Moreover, it does not soften or deform at high temperatures. The deformation of the two is "asynchronous". This means that the thermal expansion of FR-4 during the pressing and heating stage is much greater than that of the ceramic block. FR-4 is constrained by the ceramic block and reacts on the ceramic block to generate compressive stress. The shrinkage of FR-4 during cooling is also much greater than that of the ceramic block, resulting in a "shrinkage mismatch" between FR-4 and the ceramic block. This generates huge internal stress, and the stress on the ceramic block changes from "compressive stress" to "tensile stress". The ceramic block is prone to displacement and cracking problems, and the area where the ceramic block is located may also experience "bowing".

[0057] In this embodiment of the application, by setting a stress groove 12 spaced apart from the embedded groove 11, and the stress groove 12 penetrating the embedded layer 10 along the arrangement direction of the embedded layer 10 and the first additional layer 30, the embedded block 40 can be less affected by the stress generated by the embedded layer 10, thereby improving the positional displacement of the embedded block 40 and the "bending" problem in the area where the embedded block 40 is located.

[0058] As can be seen from the above, the embedded PCB manufacturing method provided in this application embodiment has embedded grooves 11 and stress grooves 12 in the embedded layer 10, which are spaced apart. An embedded block 40 is provided in the embedded groove 11, and the stress grooves 12 penetrate the embedded layer 10 along the arrangement direction of the embedded layer 10 and the first reinforcement layer 30. Therefore, when the embedded layer 10, the first adhesive layer 20 and the first reinforcement layer 30 are pressed together, the embedded block 40 is not affected by the stress generated by the embedded layer 10 or is less affected by the stress generated by the embedded layer 10. This can improve the positional displacement of the embedded block 40 and the "bowing" problem in the area where the embedded block 40 is located.

[0059] Optionally, when the embedded layer 10, the first adhesive layer 20 and the first reinforcement layer 30 are stacked in sequence, the second adhesive layer 50 and the second reinforcement layer 60 can be stacked in sequence on the side of the embedded layer 10 away from the first adhesive layer 20. Subsequently, the second reinforcement layer 60, the second adhesive layer 50, the embedded layer 10, the first adhesive layer 20 and the first reinforcement layer 30 can be pressed together.

[0060] This setup allows for the creation of multi-layer embedded PCBs.

[0061] Understandably, the second adhesive layer 50 can be a prepreg, etc. The second additional layer 60 can be a single-sided copper-clad laminate, a double-sided copper-clad laminate, or a multi-layer core board, or it can be copper foil, etc.

[0062] It is also understandable that after the embedded layer 10, the first adhesive layer 20 and the first additive layer 30 are laminated to obtain the substrate, the substrate can continue to be processed by drilling, hole metallization, outer layer circuitry, solder mask, characters, surface treatment, and stencil forming, or it can be further laminated and pressed with other core boards. It can be manufactured in a conventional manner, which will not be elaborated further.

[0063] Please refer to Figures 2 to 4 In some embodiments, the side of the embedded groove 11 near the stress groove 12 is parallel to and opposite to the stress groove 12.

[0064] By adopting the above method, the embedded block 40 can be less affected by the stress generated by the embedded layer 10 through the stress groove 12, thereby better improving the positional displacement of the embedded block 40 and the "bowing" problem in the area where the embedded block 40 is located.

[0065] It is understandable that the side of the embedded groove 11 near the stress groove 12 is parallel to the stress groove 12, that is, the side of the embedded groove 11 near the stress groove 12 is parallel to the length direction of the stress groove 12.

[0066] Optionally, multiple stress grooves 12 are provided, and the multiple stress grooves 12 are spaced apart around the embedded groove 11.

[0067] This configuration allows the embedded block 40 to be less affected by the stress generated by the embedded layer 10 in multiple directions through multiple stress grooves 12, thereby better improving the positional displacement of the embedded block 40 and the "bowing" problem in the area where the embedded block 40 is located.

[0068] Optionally, the first adhesive layer 20 shields the stress groove 12; when the embedded layer 10, the first adhesive layer 20 and the first reinforcement layer 30 are pressed together, part of the first adhesive layer 20 fills the stress groove 12.

[0069] This configuration allows the stress groove 12 to be partially filled by the first adhesive layer 20, preventing the cavity formed by the stress groove 12 from affecting the performance of the embedded PCB.

[0070] Please refer to this as well. Figure 5 In some embodiments, the side of the stress groove 12 facing the groove opening of the first adhesive layer 20 is chamfered 121.

[0071] By adopting the above solution, when the embedded layer 10, the first adhesive layer 20 and the first additive layer 30 are pressed together, it can be ensured that the stress groove 12 is filled by the first adhesive layer 20, and the cavity formed by the stress groove 12 is avoided from affecting the performance of the embedded PCB.

[0072] It should be noted that chamfer 121 can be a bevel or a rounded corner, etc.

[0073] Optionally, the width of the stress groove 12 is ≤0.2mm.

[0074] This configuration ensures that the stress groove 12 is filled by the first adhesive layer 20 when the embedded layer 10, the first adhesive layer 20 and the first reinforcement layer 30 are pressed together, thus preventing the cavity formed by the stress groove 12 from affecting the performance of the embedded PCB.

[0075] Please refer to Figure 6 In another embodiment, multiple embedded grooves 11 are provided, and the multiple embedded grooves 11 are spaced apart, with one embedded groove 11 corresponding to multiple stress grooves 12.

[0076] This configuration allows multiple embedded blocks 40 to be less affected by the stress generated by the embedded layer 10 in multiple directions through multiple stress grooves 12, thereby better improving the positional displacement of the embedded blocks 40 and the "bowing" problem in the area where the embedded blocks 40 are located.

[0077] As one possible approach, a stress groove 12 is provided between two adjacent embedded grooves 11.

[0078] With this configuration, the stress groove 12 simultaneously ensures that the two embedded blocks 40 are not affected by the stress generated by the embedded layer 10 in multiple directions, or are less affected by the stress generated by the embedded layer 10 in multiple directions. This can better improve the positional displacement of the embedded block 40 and the "bending" problem in the area where the embedded block 40 is located. Moreover, it does not require the processing of a large number of stress grooves 12, making the processing simpler and more convenient.

[0079] It should be noted that the stress grooves 12 around the embedded groove 11 are not interconnected. When multiple embedded blocks 40 are embedded in the embedded layer 10 at the same time, one or more stress grooves 12 can be set between adjacent embedded blocks 40. When multiple embedded grooves 11 need to be set in the longitudinal and transverse directions, the stress groove 12 corresponding to the embedded groove 11 in a single direction is not interconnected with the stress groove 12 corresponding to the adjacent embedded groove 11, that is, a certain length of connecting rib is retained to ensure the local rigidity of the embedded layer 10.

[0080] Please refer to Figure 2 , Figure 4 and Figure 7 In some embodiments, one of the inner wall of the embedding groove 11 and the embedding block 40 is provided with a protrusion 13, and the other of the inner wall of the embedding groove 11 and the embedding block 40 abuts against the protrusion 13.

[0081] By adopting the above scheme, during the pressing process of embedding layer 10, first adhesive layer 20 and first reinforcement layer 30, a gap is formed between the inner wall of embedding groove 11 and embedding block 40 through protrusion 13, thereby reducing the stress of the inner wall of embedding groove 11 directly on embedding block 40.

[0082] As one possible implementation method, the height of the protrusion 13 protruding from the inner wall of the embedded groove 11 is ≤0.3mm, and the width of the protrusion 13 along the inner wall direction of the embedded groove 11 is ≥2mm.

[0083] Optionally, multiple protrusions 13 are provided, and the multiple protrusions 13 are spaced apart around the axis of the embedded groove 11.

[0084] With this configuration, gaps can be formed between the inner wall of the embedding groove 11 and the embedding block 40 in multiple directions through multiple protrusions 13, thereby reducing the stress on the embedding block 40 directly from the inner wall of the embedding groove 11 in multiple directions.

[0085] It is understood that multiple protrusions 13 can be respectively provided on different inner walls of the embedding groove 11, and the area defined by each protrusion 13 is larger than the size of the embedding block 40 but smaller than the size of the embedding groove 11, so that the embedding block 40 can be smoothly inserted.

[0086] It is also understandable that the protrusion 13 allows the embedded block 40 to be better positioned relative to the embedded groove 11 when it is placed in the embedded groove 11, thereby improving the embedding accuracy of the ceramic embedded block 40.

[0087] As one possible approach, a recessed locking position is provided at the position corresponding to the protrusion 13 of the embedded block 40. When the embedded block 40 is placed in the embedded groove 11, the protrusion 13 matches the locking position (the gap between the two is ≤0.1mm), thereby improving the embedding accuracy of the embedded block 40.

[0088] Secondly, embodiments of this application provide an embedded PCB, which is manufactured by the embedded PCB manufacturing method as described in the first aspect.

[0089] The embedded PCB provided in this application embodiment has an embedded layer 10 with an embedded groove 11 and a stress groove 12, which are spaced apart. An embedded block 40 is provided in the embedded groove 11, and the stress groove 12 penetrates the embedded layer 10 along the arrangement direction of the embedded layer 10 and the first reinforcement layer 30. Therefore, when the embedded layer 10, the first adhesive layer 20 and the first reinforcement layer 30 are pressed together, the embedded block 40 is not affected by the stress generated by the embedded layer 10 or is less affected by the stress generated by the embedded layer 10. This can improve the positional displacement of the embedded block 40 and the "bending" problem in the area where the embedded block 40 is located.

[0090] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method of manufacturing a buried PCB, characterized by, The application relates to a buried embedding PCB manufacturing method. The embedding layer, the first bonding layer and the first increment layer are sequentially stacked, the embedding layer is provided with embedding grooves and stress grooves, the embedding grooves and the stress grooves are arranged at intervals, embedding blocks are arranged in the embedding grooves, the thermal expansion coefficient of the embedding layer is greater than the thermal expansion coefficient of the embedding blocks, and the stress grooves penetrate the embedding layer along the arrangement direction of the embedding layer and the first increment layer. The embedding layer, the first bonding layer and the first increment layer are subjected to a pressing treatment, and part of the first bonding layer fills the gap between the inner wall of the embedding groove and the embedding block.

2. The method of claim 1, wherein, The side edge of the embedding groove close to the stress groove is arranged in parallel with and opposite to the stress groove.

3. The method of claim 1, wherein the method further comprises: The stress grooves are arranged at intervals around the embedding groove.

4. The method of claim 3, wherein the step of forming the embedded PCB is performed by a process selected from the group consisting of a subtractive process, a semi-additive process, and a full-additive process. The embedding grooves are arranged at intervals, and one embedding groove corresponds to a plurality of stress grooves.

5. The method of claim 4, wherein the step of forming the embedded PCB is performed by a process selected from the group consisting of a subtractive process, a semi-additive process, and a full-additive process. The stress grooves are arranged between two adjacent embedding grooves.

6. The method of claim 1, wherein, The first bonding layer covers the stress grooves, and part of the first bonding layer fills the stress grooves during the pressing treatment of the embedding layer, the first bonding layer and the first increment layer.

7. The method of claim 6, wherein the method further comprises: The side edge of the stress groove opening towards the first bonding layer is chamfered.

8. The method of claim 1 to 7, wherein, One of the inner wall of the embedding groove and the embedding block is provided with a protruding part, and the other of the inner wall of the embedding groove and the embedding block abuts against the protruding part.

9. The method of claim 8, wherein the method further comprises: The protruding parts are arranged at intervals around the axis of the embedding groove.

10. A buried PCB, characterized by, The buried embedding PCB is processed by the buried embedding PCB manufacturing method in any one of claims 1 to 9.

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