Printed circuit board and preparation method thereof

Abstract

The invention discloses a printed circuit board and a preparation method thereof, and the method comprises the steps: obtaining a basic circuit board and an installed object; solder is arranged on a bonding pad of the installed object, and a plurality of conductive bosses are correspondingly prepared on the basic circuit board based on the position of the bonding pad; and the solder of the installed object is correspondingly attached to the corresponding conductive boss, and the solder is melted, so that the solder is melted and wraps the outer surface of the conductive boss, and the installed object is installed on the basic circuit board. Through the mode, the connection distance between the bonding pad of the installed object and the conductive boss can be shortened, and the phenomenon of solder voids is reduced, so that the influence on the signal transmission performance is reduced, the transmission signal is reduced, and the signal transmission stability, integrity and reliability between the installed object and the basic circuit board are improved.

Description

Technical Field

[0001] The present invention is applied to the technical field of printed circuit boards, in particular to a printed circuit board and a preparation method thereof. Background Art

[0002] PCB (Printed Circuit Board), also known as printed circuit board or printed circuit board, is an important electronic component with wide application. It is the support body of electronic components and also the carrier of electrical connection of electronic components.

[0003] Printed circuit boards serve as carriers of electronic components and chips, and are interconnected with components, chips, etc. through solder.

[0004] Due to factors such as voids in the solder and solder size, the solder has significant signal transmission loss in the interconnection, especially near the feed port, which has a great impact on signal transmission performance. Summary of the Invention

[0005] The present invention provides a printed circuit board and a preparation method thereof, so as to solve the problem that soldering of the printed circuit board has a great influence on signal transmission performance.

[0006] To solve the above technical problems, the present invention provides a method for preparing a printed circuit board, comprising: obtaining a base circuit board and an object to be installed; setting solder on the pads of the object to be installed, and preparing a plurality of conductive bosses on the base circuit board based on the positions of the pads; fitting the solder of the object to be installed with the corresponding conductive bosses, and melting the solder so that the solder melts and covers the outer surface of the conductive bosses, so as to install the object to be installed on the base circuit board.

[0007] The step of setting solder on the pad of the object to be mounted includes setting solder on the pad of the object to be mounted by chemically depositing solder, electroplating solder, laser spot tinning, screen printing solder paste, or dipping solder.

[0008] Among them, the depth of the position on the protective layer corresponding to the pad of the installed object is controlled, including: controlling the depth of the position on the protective layer corresponding to the pad of the installed object by UV laser depth control milling, CO2 laser depth control milling or mechanical milling machine depth control milling.

[0009] Among them, based on the position of the solder pad, a plurality of conductive bosses are prepared on the basic circuit board, including: pressing a protective layer on the target side of the basic circuit board; controlling the depth of the position corresponding to the solder pad of the installed object on the protective layer until reaching the target side of the basic circuit board, so as to prepare a plurality of controlled depth grooves on the protective layer; electroplating the controlled depth grooves to form conductive bosses; wherein the conductive bosses are connected to the basic circuit board; and removing the remaining protective layer to expose the conductive bosses.

[0010] The protective layer includes a conductive adhesive layer; removing the remaining protective layer to expose the conductive boss includes: soaking the conductive adhesive layer in a potassium permanganate solution or a sodium hydroxide solution to remove the remaining conductive adhesive layer.

[0011] Among them, the controlled depth groove is electroplated to form a conductive boss, including: electroplating the entire board on the side of the protective layer away from the basic circuit board until the controlled depth groove is fully filled; grinding the side of the protective layer away from the basic circuit board to grind the electroplated layer in the controlled depth groove to form a conductive boss, and removing the electroplated layer on the surface of the protective layer.

[0012] Among them, obtaining a basic circuit board includes: obtaining a substrate, the substrate including at least one conductive layer and at least one dielectric layer alternately stacked in sequence; performing local solder mask treatment on opposite sides of the substrate and exposing the external connection port to obtain a basic circuit board; the external connection port at least corresponds to the conductive boss.

[0013] The height of the conductive boss is in the range of 15-500 microns; the length of the conductive boss is in the range of 25%-95% of the length of the corresponding pad on the mounted object; and the width of the conductive boss is in the range of 25%-95% of the width of the corresponding pad on the mounted object.

[0014] In order to solve the above technical problems, the present invention also provides a printed circuit board comprising: a base circuit board, multiple solders and an object to be installed, a plurality of conductive bosses are formed on the target side of the base circuit board, the solder is arranged to cover the outer surface of the corresponding conductive bosses, and the pad of the object to be installed is connected to the side of the solder away from the conductive bosses to be fixedly connected to the base circuit board.

[0015] The solder wraps around the side surfaces of the conductive boss and the top surface of the conductive boss away from the base circuit board.

[0016] To solve the above technical problems, the method for preparing a printed circuit board of the present invention obtains a base circuit board and an object to be installed; sets solder on the pads of the object to be installed, and prepares a plurality of conductive bosses on the base circuit board based on the positions of the pads; places the solder of the object to be installed in correspondence with the corresponding conductive bosses, and melts the solder so that the solder melts and covers the outer surface of the conductive bosses, so that the object to be installed is installed on the base circuit board. After the solder melts and covers the outer surface of the conductive bosses, the connection distance between the pads of the object to be installed and the conductive bosses is shortened and the phenomenon of solder voids is reduced, thereby reducing the impact on signal transmission performance, reducing the transmission signal, and improving the stability, integrity and reliability of signal transmission between the object to be installed and the base circuit board. Among them, the overall surface area of ​​the solder increases after melting, which can improve the connection stability between the solder and the conductive bosses by increasing the contact area between the solder and the conductive bosses, thereby ensuring both connection stability and signal transmission stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic flow chart of an embodiment of a method for preparing a printed circuit board provided by the present invention;

[0018] Figure 2 This is a schematic flow chart of another embodiment of the method for preparing a printed circuit board provided by the present invention;

[0019] Figure 3 yes Figure 2 A schematic structural diagram of the preparation process in the embodiment;

[0020] Figure 4 It is a structural schematic diagram of an embodiment of the printed circuit board provided by the present invention. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0022] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain 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 invention, 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 number of the indicated technical features. Therefore, the features specified as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0024] See also Figure 1 , Figure 1 The figure is a flow chart of an embodiment of a method for preparing a printed circuit board provided by the present invention.

[0025] Step S11: Acquire the basic circuit board and the object to be installed.

[0026] The basic circuit board includes at least one conductive layer and at least one dielectric layer alternately stacked in sequence, with the specific number of layers including but not limited to 5 layers, 10 layers, 20 layers, 25 layers or 30 layers.

[0027] The objects to be installed include but are not limited to chips, chip packages, chip components, transformers, inductors, capacitors, relays, sensors and other electronic devices that require signal transmission.

[0028] Step S12: Solder is provided on the pads of the mounting object, and a plurality of conductive bosses are correspondingly prepared on the base circuit board based on the positions of the pads.

[0029] Solder is pre-applied to the pads of the mounting objects. The solder type includes a tin layer. The number of mounting objects can be one or more, such as 1, 3, 4, 5, 7, or 10, etc., and is not limited here. The number of pads for each mounting object can be one or more, and the specific setting is based on actual conditions.

[0030] Based on the locations of the solder pads, multiple conductive bumps are fabricated on the base circuit board. These bumps are taller than other locations on that side of the base circuit board. If the object is to be mounted on one side of the base circuit board, the conductive bumps are fabricated on that side. If the object is to be mounted on two opposing sides of the base circuit board, the conductive bumps are fabricated on those opposite sides.

[0031] In a specific application scenario, the conductive bosses can be formed at corresponding positions on the base circuit board by local electroplating. In a specific application scenario, the conductive bosses can also be formed by welding the metal base to corresponding positions on the base circuit board. The specific preparation method is not limited here.

[0032] Step S13: The solder of the object to be mounted is fitted to the corresponding conductive boss, and the solder is melted to melt and cover the outer surface of the conductive boss, so as to mount the object to be mounted on the base circuit board.

[0033] The solder of the object to be mounted is fitted with the corresponding conductive boss, and the pad of the object to be mounted is arranged correspondingly to the conductive boss.

[0034] The solder is melted at high temperature, coating the outer surface of the conductive bumps. The molten solder then connects the pads of the object to be mounted to the conductive bumps, and the object is then mounted on the base circuit board. The object is then connected to the base circuit board via the solder, the conductive bumps, and the base circuit board.

[0035] After the solder melts and coats the outer surface of the conductive boss, it shortens the connection distance between the mounting pad and the conductive boss and reduces solder voiding, thereby reducing the impact on signal transmission performance and the transmitted signal, thereby improving the stability, integrity, and reliability of signal transmission between the mounting object and the base circuit board. The solder's overall surface area increases after melting, increasing both the contact area with the conductive boss, thereby improving connection stability, and the contact area with the air, thereby increasing the heat dissipation area and improving heat dissipation efficiency. The provision of the conductive boss also elevates the mounting position of the mounting object to a certain extent, thereby reducing the possibility of collision between the mounting object and other locations on the base circuit board and increasing the mounting freedom of the mounting object.

[0036] Through the above steps, the method for preparing a printed circuit board of this embodiment includes: obtaining a base circuit board and an object to be installed; setting solder on the pads of the object to be installed, and preparing a plurality of conductive bosses on the base circuit board based on the positions of the pads; aligning the solder of the object to be installed with the corresponding conductive bosses, and melting the solder so that the solder melts and covers the outer surface of the conductive bosses, so that the object to be installed is installed on the base circuit board. After the solder melts and covers the outer surface of the conductive bosses, the connection distance between the pads of the object to be installed and the conductive bosses is shortened and solder voids are reduced, thereby reducing the impact on signal transmission performance, reducing the transmission signal, and improving the stability, integrity, and reliability of signal transmission between the object to be installed and the base circuit board. Among them, the overall surface area of ​​the solder increases after melting, which can improve the connection stability between the solder and the conductive bosses by increasing the contact area between the solder and the conductive bosses, thereby ensuring both connection stability and signal transmission stability.

[0037] See also Figure 2-3 , Figure 2 The figure is a flow chart of another embodiment of the method for preparing a printed circuit board provided by the present invention. Figure 3 yes Figure 2 Schematic diagram of the preparation process in the embodiment.

[0038] Step S21: Acquire the basic circuit board and the object to be installed.

[0039] See also Figure 3 In (3a), a substrate 15 is obtained, and the substrate 15 includes at least one conductive layer 11 and at least one dielectric layer 12 alternately stacked in sequence; local solder mask treatment is performed on opposite sides of the substrate 15, and solder mask layers 14 are provided on opposite sides of the substrate 15, and the external connection port 13 is exposed to obtain a basic circuit board 10; the position of the external connection port 13 at least corresponds to the conductive boss.

[0040] The substrate 15 can be obtained by sequentially laminating the dielectric layer 12 and the conductive layer 11 on opposite sides of the core board. Alternatively, the finished substrate 15 can be obtained directly.

[0041] The external connection port 13 is used to connect external electronic devices. The conductive bosses are designed to connect electronic devices with high signal transmission requirements, such as chips and sensors. However, electronic devices with lower signal transmission requirements can also be directly soldered to the external connection port 13. Therefore, the positions of the multiple external connection ports 13 correspond at least to the conductive bosses and may also correspond to the connection positions of other electronic devices, depending on actual needs.

[0042] The objects to be installed include but are not limited to chips, chip packages, chip components, transformers, inductors, capacitors, relays, sensors and other electronic devices that require signal transmission.

[0043] Step S22: Solder is provided on the pad of the mounting object by chemically depositing solder, electroplating solder, laser spot tinning, stencil printing solder paste or immersion tinning.

[0044] See also Figure 3 In (3b), solder 23 is provided on a pad (not shown) of the mounting object 20 by chemical solder deposition, electroplating, laser spot tinning, screen printing of solder paste, or immersion tinning. The thickness of the solder 23 ranges from 1 to 100 μm, and can specifically be 1 μm, 5 μm, 10 μm, 16 μm, 18 μm, 25 μm, 29 μm, 35 μm, 38 μm, 45 μm, 49 μm, 52 μm, 57 μm, 68 μm, 69 μm, 72 μm, 79 μm, 88 μm, 95 μm, or 100 μm, depending on the size of the pad and the conductive boss.

[0045] This embodiment is explained by taking the mounted object 20 as a chip package as an example. The mounted object 20 includes a chip 21 and a packaging substrate 22 that are bonded and connected to each other. A plurality of pads are formed on the side of the packaging substrate 22 away from the chip 21, and the pads are bonded to the solder 23 accordingly.

[0046] In other embodiments, the installed object may also be a separate chip, a combination of a chip and other devices, or other electronic devices, etc., which is not limited here.

[0047] Step S23: Laminating a protective layer on the target side of the base circuit board; controlling the depth of the position corresponding to the pad on the protective layer until reaching the target side of the base circuit board, so as to prepare a plurality of depth-controlled grooves on the protective layer.

[0048] See also Figure 3 In step (3c), based on step (3a), a protective layer 16 is laminated on the target side of the base circuit board 10. The target side is the side where the device to be mounted is to be mounted, and can be one side or two opposite sides of the base circuit board 10, depending on actual needs.

[0049] After lamination, the protective layer 16 fills the gap between the solder resist layer 14 on the target side of the base circuit board 10 and the external connection port 13. A metal layer 17 may be provided on the side of the protective layer 16 away from the base circuit board 10 to assist in lamination.

[0050] See also Figure 3In (3d), based on (3c), depth control is performed on the protective layer 16 at positions corresponding to the pads of the mounting object 20 until the target side of the base circuit board 10 is reached, thereby forming a plurality of depth-controlled grooves 18 on the protective layer 16. The depth-controlled grooves 18 expose at least a portion of the external connection port 13.

[0051] Using UV laser controlled deep milling, CO2 laser controlled deep milling, or mechanical milling machine controlled deep milling, the protective layer 16 and metal layer 17 are milled away at the location where the conductive boss is to be formed according to the designed dimensions, exposing the external connection port 13 at the corresponding location on the bottom base circuit board 10. The external connection port 13 can specifically be a conductive pad for connection.

[0052] Step S24: electroplating the depth-controlled groove to form a conductive boss; wherein the conductive boss is connected to the base circuit board; and removing the remaining protective layer to expose the conductive boss.

[0053] See also Figure 3 In (3e), (3e) is based on (3d), the depth control groove 18 is electroplated to form a conductive boss 19; wherein the conductive boss 19 is connected to the base circuit board 10; the remaining protective layer 16 is removed to expose the conductive boss 19.

[0054] The depth controlled groove 18 can be cleaned before electroplating to improve the subsequent electroplating effect.

[0055] Specifically, the entire side of the protective layer 16 away from the basic circuit board 10 can be electroplated first until the fully controlled deep groove 18 is filled; then the side of the protective layer 16 away from the basic circuit board 10 is ground flat to remove the electroplating layer on the surface of the protective layer 16 for subsequent removal and to grind the electroplating layer in the controlled deep groove 18 to form a conductive boss 19.

[0056] The conductive boss 19 is prepared by electroplating, so that the conductive boss 19 can be directly connected to the external connection port 13 without any other adhesive, thereby further improving the reliability and integrity of signal transmission.

[0057] In a specific application scenario, the smoothing treatment can be performed by chemical micro-etching, mechanical brushing, ceramic brushing, scraping brushing or non-woven brushing.

[0058] In a specific application scenario, the protective layer 16 may be a conductive adhesive layer. In this step, the conductive adhesive layer may be soaked in a potassium permanganate solution or a sodium hydroxide solution to remove the remaining conductive adhesive layer.

[0059] The height range of the conductive boss 19 is 15-500 microns; specifically, it can be 15 microns, 20 microns, 28 microns, 35 microns, 50 microns, 87 microns, 99 microns, 102 microns, 160 microns, 240 microns, 350 microns, 380 microns, 400 microns, 460 microns or 500 microns, etc.

[0060] The length of the conductive boss 19 ranges from 25% to 95% of the length of the corresponding pad on the mounted object 20; specifically, it can be 25%, 30%, 39%, 42%, 49%, 55%, 67%, 77%, 88% or 95%, etc.

[0061] The width of the conductive boss 19 is in the range of 25%-95% of the width of the corresponding pad on the mounted object 20. Specifically, it can be 25%, 31%, 38%, 43%, 49%, 55%, 67%, 77%, 88% or 95%, etc.

[0062] The conductive boss 19 within the above-mentioned size range can match the size of the corresponding pad on the mounted object 20, thereby improving the subsequent connection stability and reliability.

[0063] Step S25: The solder of the object to be mounted is fitted to the corresponding conductive boss, and the solder is melted to melt and cover the outer surface of the conductive boss, so as to mount the object to be mounted on the base circuit board.

[0064] See also Figure 3 In (3f), based on (3e), the solder 23 of the object 20 to be mounted is aligned with the corresponding conductive boss 19, and the solder 23 is melted so that the solder 23 melts and covers the outer surface of the conductive boss 19, thereby mounting the object 20 on the base circuit board 10. The solder 23 covers the four sides of the conductive boss 19 and the top surface of the conductive boss 19 away from the base circuit board 10.

[0065] After the solder 23 melts and coats the outer surface of the conductive boss 19, it shortens the connection distance between the pad of the object 20 and the conductive boss 19 and reduces solder voids, thereby reducing the impact on signal transmission performance and the transmitted signal, thereby improving the stability, integrity, and reliability of signal transmission between the object 20 and the base circuit board 10. The increased surface area of ​​the solder 23 after melting not only increases the contact area with the conductive boss 19, thereby improving connection stability, but also increases the contact area with the air, thereby increasing the heat dissipation area and promoting heat dissipation efficiency. The provision of the conductive boss 19 also elevates the mounting position of the object 20 to a certain extent, thereby reducing the possibility of collision between the object 20 and other locations on the base circuit board 10 and increasing the installation freedom of the object 20.

[0066] Through the above steps, the method for preparing a printed circuit board of this embodiment includes: preparing a plurality of conductive bosses on a base circuit board based on the positions of the solder pads; placing the solder of the object to be mounted on the corresponding conductive bosses in a corresponding manner, and melting the solder so that the solder melts and covers the outer surface of the conductive bosses, so that the object to be mounted is mounted on the base circuit board. After the solder melts and covers the outer surface of the conductive bosses, the connection distance between the solder pads of the object to be mounted and the conductive bosses is shortened and solder voids are reduced, thereby reducing the impact on signal transmission performance, reducing the transmission signal, and improving the stability, integrity, and reliability of signal transmission between the object to be mounted and the base circuit board. Among them, the overall surface area of ​​the solder increases after melting, which can improve the connection stability between the solder and the conductive bosses by increasing the contact area between the solder and the conductive bosses, thereby ensuring both connection stability and signal transmission stability.

[0067] See also Figure 4 , Figure 4 1 is a schematic structural diagram of an embodiment of a printed circuit board provided by the present invention. The printed circuit board of this embodiment is prepared by the method for preparing a printed circuit board of any of the above embodiments.

[0068] The printed circuit board 300 of this embodiment includes: a base circuit board 34, a plurality of solders 32, and an object to be mounted 31. The number and type of the objects to be mounted 31 can be one or more.

[0069] A plurality of conductive bosses 33 are formed on the target side of the base circuit board 34; this side is the side of the base circuit board 34 where the mounting object 31 is to be mounted. Solder 32 covers the outer surfaces of the corresponding conductive bosses 33. The pads of the mounting object 31 connect to the solder 32 on the side away from the conductive bosses 33, thereby securing the mounting object 31 to the base circuit board 34.

[0070] The mounted object 31 may be connected to the base circuit board 34 via one conductive boss 33 or via multiple conductive bosses 33 , which is not limited here.

[0071] By melting the solder and coating the outer surface of the conductive boss, the connection distance between the mounting pad and the conductive boss is shortened and solder voids are reduced, thereby reducing the impact on signal transmission performance, lowering the transmission signal, and improving the stability, integrity, and reliability of signal transmission between the mounting object and the base circuit board. The overall surface area of ​​the solder increases after melting, increasing both the contact area with the conductive boss, thereby improving connection stability, and the contact area with the air, thereby increasing the heat dissipation area and improving heat dissipation efficiency. The provision of the conductive boss also elevates the mounting position of the mounting object to a certain extent, thereby reducing the possibility of collision between the mounting object and other locations on the base circuit board and increasing the mounting freedom of the mounting object.

[0072] In some embodiments, the solder 32 wraps around the four sides of the conductive boss 33 and the top surface of the conductive boss 33 away from the base circuit board 34 to maximize the contact area with the conductive boss, thereby improving connection stability and heat dissipation efficiency.

[0073] In some embodiments, the height of the conductive boss 33 ranges from 15 to 500 microns; specifically, it can be 15, 20, 28, 35, 50, 87, 99, 102, 160, 240, 350, 380, 400, 460, or 500 microns. Conductive bosses 33 within this height range can reduce the likelihood of collision between the mounted object 31 and other locations on the base circuit board 34, thereby increasing the freedom of mounting the mounted object 34.

[0074] In some embodiments, the printed circuit board 300 includes an electronic device 38 , which is directly soldered and fixed to an external connection port on the base circuit board 34 .

[0075] The above description is only an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a printed circuit board, characterized in that: The method for preparing the printed circuit board comprises: Get the basic circuit board and the object to be installed; Disposing solder on the pads of the mounted object, and preparing a plurality of conductive bosses corresponding to the positions of the pads on the base circuit board; The solder of the object to be mounted is fitted correspondingly to the corresponding conductive boss, and the solder is melted to melt and cover the outer surface of the conductive boss, so that the object to be mounted is mounted on the basic circuit board.

2. The method for preparing a printed circuit board according to claim 1, wherein: The step of providing solder on the pad of the mounted object comprises: Solder is provided on the pad of the mounted object by chemically depositing solder, electroplating solder, laser spot tinning, screen printing solder paste or immersion tinning.

3. The method for preparing a printed circuit board according to claim 1 or 2, wherein: The step of preparing a plurality of conductive bosses on the basic circuit board based on the positions of the pads includes: laminating a protective layer on the target side of the base circuit board; Controlling the depth of positions on the protective layer corresponding to the pads of the mounted object until reaching the target side of the base circuit board, thereby preparing a plurality of depth-controlled grooves on the protective layer; Electroplating the depth-controlled groove to form the conductive boss; wherein the conductive boss is connected to the base circuit board; The remaining protection layer is removed to expose the conductive boss.

4. The method for preparing a printed circuit board according to claim 3, wherein: The controlling the depth of a position on the protective layer corresponding to the pad of the mounted object comprises: The depth of the position on the protective layer corresponding to the soldering pad of the mounted object is controlled by UV laser controlled deep milling, CO2 laser controlled deep milling or mechanical milling machine controlled deep milling.

5. The method for preparing a printed circuit board according to claim 3, wherein: The protective layer includes a conductive adhesive layer; The step of removing the remaining protective layer to expose the conductive boss comprises: The conductive adhesive layer is soaked in potassium permanganate solution or sodium hydroxide solution to remove the remaining conductive adhesive layer.

6. The method for preparing a printed circuit board according to claim 3, wherein: The electroplating of the depth-controlled groove to form the conductive boss comprises: Performing whole-board electroplating on a side of the protective layer away from the basic circuit board until the depth-controlled groove is fully filled; The side of the protective layer away from the basic circuit board is ground flat to grind the electroplating layer in the depth-controlled groove to form the conductive boss, and the electroplating layer on the surface of the protective layer is ground off.

7. The method for preparing a printed circuit board according to claim 1, wherein: The obtaining of the basic circuit board includes: Obtaining a substrate, wherein the substrate includes at least one conductive layer and at least one dielectric layer alternately stacked in sequence; Local solder resist treatment is performed on opposite sides of the substrate, and external connection ports are exposed to obtain the basic circuit board; the external connection ports at least correspond to the conductive bosses.

8. The method for preparing a printed circuit board according to claim 1, wherein: The height of the conductive boss is in the range of 15-500 microns; The length of the conductive boss is in the range of 25% to 95% of the length of the corresponding pad on the mounted object; The width of the conductive boss is in the range of 25% to 95% of the width of the corresponding pad on the mounted object.

9. A printed circuit board, characterized in that: The printed circuit board is prepared by the method for preparing a printed circuit board according to any one of claims 1 to 8, comprising: a base circuit board having a plurality of conductive bosses formed on a target side of the base circuit board; A plurality of solders, wherein the solders are arranged to cover the outer surfaces of the corresponding conductive bosses; The object to be mounted has a pad connected to a side of the solder away from the conductive boss to be fixedly connected to the base circuit board.

10. The printed circuit board according to claim 9, characterized in that The solder wraps around the four sides of the conductive boss and the top surface of the conductive boss away from the basic circuit board.

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