Crimping blind hole PCB

Abstract

The utility model discloses a crimping blind hole PCB, and belongs to the technical field of PCB manufacturing. The crimping blind hole PCB comprises at least two sub-boards and prepregs installed between the two adjacent sub-boards. The daughter board is provided with a crimping hole, and the prepreg opposite to the crimping hole is provided with a laser hole; the diameter of the laser hole is greater than that of the crimping hole; a glue blocking ring coaxial with the crimping hole is installed in the laser hole, glue storage grooves are formed in the periphery of the daughter board part opposite to the laser hole, and the glue storage grooves of the adjacent daughter boards are distributed in a staggered mode. According to the utility model, the glue blocking rings are arranged around the crimping holes on the daughter boards, and the glue storage grooves are arranged at the laser holes in a staggered manner, so that glue blocking between the through holes of the daughter boards is carried out, PP (polypropylene) flowing glue can be prevented from blocking the crimping holes after prepregs are melted when the daughter boards are laminated, and the prepregs in high flow state can be used for bonding between the daughter boards.

Description

Technical Field

[0001] This utility model relates to the field of PCB board manufacturing technology, and in particular to a crimp-bonded blind hole PCB board. Background Technology

[0002] With the development of technology, the communication industry has increasingly higher requirements for signal transmission capabilities. Due to the limitations of chassis size, the size of PCB boards cannot be increased. Therefore, rationally planning PCB wiring to increase the number of traces and connectors has become a trend.

[0003] Traditional PCBs can only accommodate connectors on one side, resulting in a limited number of connectors per board area. This necessitates the use of multiple PCBs to achieve higher data transmission speeds, leading to higher costs and greater thickness, which does not meet the size requirements of end devices. By implementing both insertion and soldering on a single PCB, the number of connectors can be significantly increased, saving costs while simultaneously improving the product's signal transmission capabilities and achieving higher integration.

[0004] Existing crimped blind hole board manufacturing processes require the use of low-flow prepreg for bonding between sub-boards. To avoid PP glue overflow and clogging of holes, low-flow prepreg is commonly used. However, the low flow rate of this prepreg is also a fatal flaw for PCB reliability, as it cannot withstand stringent thermal stress requirements. Therefore, it can only be used in some fully crimped backplane products and cannot be used in other PCB products that require both soldering and crimping. For high-flow prepreg, there is a risk of glue overflow into the holes. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a press-fit blind via PCB board. By opening laser holes in the prepreg and using adhesive resistance rings and staggered adhesive reservoirs to prevent adhesive from entering between sub-boards, high-flow prepreg can be used as the adhesive between sub-boards. This type of press-fit blind via PCB board can be extended to motherboards and cardboard for application, no longer limited to using low-flow prepreg as the adhesive between sub-boards.

[0006] To achieve the above objectives, this utility model employs the following technical solution:

[0007] On the one hand, this utility model provides a press-fit blind hole PCB board, including at least two sub-boards and a prepreg installed between two adjacent sub-boards;

[0008] The sub-board has crimping holes, and the prepreg opposite to the crimping holes has laser holes; the diameter of the laser holes is larger than the diameter of the crimping holes.

[0009] An adhesive-resistant ring coaxial with the crimping hole is installed inside the laser hole. An adhesive storage groove is provided around the periphery of the sub-board portion opposite to the laser hole, and the adhesive storage grooves of adjacent sub-boards are staggered.

[0010] Optionally, the inner diameter of one of the adhesive-resistant rings is greater than or equal to the diameter of the crimping hole, and the inner diameter of the other adhesive-resistant ring is greater than the diameter of the crimping hole, with the two adhesive-resistant rings forming a nested structure.

[0011] If the inner diameter of one of the adhesive-resistant rings is equal to the diameter of the crimping hole, then the adhesive-resistant ring is the hole ring of the crimping hole.

[0012] Optionally, the width of the adhesive resist ring can be set according to the thickness of the prepreg.

[0013] Optional features include back-drilling and deep drilling;

[0014] The back drill hole is coaxially connected to the crimping hole through a deep drill hole, and the back drill hole is located on the side away from the prepreg.

[0015] Optionally, the inner surface of the crimping hole is coated with an electroplated layer, and the inner surface of the back-drilled hole is coated with an electroplated layer.

[0016] Optionally, D > d1 > d; where D represents the diameter of the back drill hole, d1 represents the diameter of the deep drill hole, and d represents the diameter of the crimping hole.

[0017] Optionally, the diameter d of the crimping hole is at most D-0.4mm.

[0018] Optionally, each of the sub-boards includes multiple metal layers and a dielectric layer located between two adjacent metal layers. Beneficial effects

[0019] Compared with the prior art, the beneficial effects achieved by this utility model are as follows:

[0020] This invention prevents the PP adhesive from flowing out and clogging the press-fit holes by setting a blocking ring around the press-fit holes on the sub-board and staggering the glue storage tanks at the laser holes. It can prevent the prepreg from melting and clogging the press-fit holes during the pressing of the sub-boards. High-flow prepreg can be used as the adhesive between the sub-boards. This invention extends the application of this type of press-fit blind hole PCB board to motherboards and cardboard, no longer limiting the use of low-flow prepreg as the adhesive between the sub-boards. Attached Figure Description

[0021] Figure 1 The diagram shown is a structural schematic of one embodiment of the press-fit blind hole PCB board of this utility model;

[0022] Figure 2 The diagram shown is a schematic representation of the installation structure of the crimping hole and the adhesive-resistant ring in one embodiment of the present invention.

[0023] In the diagram: 1-Crimping hole; 2-Deep drilled hole; 3-Back drilled hole; 4-Resistant ring; 5-Resistant reservoir; 6-Prepreg; 7-Subboard. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features therein are detailed descriptions of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features therein can be combined with each other.

[0025] The term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0026] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0028] Example 1

[0029] This embodiment introduces a press-fit blind hole PCB board, including at least two sub-boards 7 and a prepreg 6 installed between two adjacent sub-boards 7.

[0030] The sub-board 7 has a crimping hole 1. There is at least one crimping hole 1 on the sub-board 7. This design is not limited to one sub-board and can also be applied to two sub-boards 7 with crimping holes 1. Each sub-board 7 can have one or more crimping holes 1. The crimping holes 1 are drilled mechanically.

[0031] Sub-board 7 drills the crimping holes 1 that need to be metallized. The process here is not specifically limited depending on the requirements. If there are holes that need resin plugging, they can be drilled in stages: first, drill the holes requiring resin plugging for electroplating, and then drill the crimping holes 1. The crimping hole 1 is set according to the hole type. For non-high-speed holes (without back drilling), the diameter is set directly according to the required diameter. For high-speed holes (with back drilling), the diameter needs to be set in conjunction with the diameter of the back-drilled hole 3. For example, if the diameter of the back-drilled hole 3 is D, then the maximum diameter d of the crimping hole 1 is D-0.4mm. While meeting the requirements for subsequent hole plugging printing and back drilling capabilities, the diameter of the crimping hole 1 should be set as small as possible to avoid voids during subsequent hole plugging. For example, the diameter d of the crimping hole 1 is 0.4mm.

[0032] The daughterboard 7 may include multiple metal layers and a dielectric layer located between two adjacent metal layers. The metal layers include electrical components such as transistors, diodes, resistors, interconnects, and pins. The dielectric layer can achieve mutual insulation between lines and / or devices on different metal layers, preventing misconnection of lines and / or devices on two metal layers, which could lead to malfunction.

[0033] In the production or testing process of the circuit board, the crimp hole 1 enables signal transmission between the sub-board 7 and the component when the component's pin is inserted, without the need to solder the component to the sub-board, making it convenient to replace components and easy to operate.

[0034] Laser holes are formed on the prepreg 6 opposite to the crimp hole 1. The laser holes are formed by PP laser burning. The purpose of PP laser burning is to pre-cure the PP around the crimp hole 1 and avoid the risk of glue flowing into the crimp hole. If there are other heating methods or the prepreg 6 is enlarged to control the glue flow, the corresponding holes are burned into the prepreg 6 by laser burning according to the position of the crimp hole 1. The purpose of this is to solve the risk of glue flowing into the hole.

[0035] The back-drilled hole 3 is coaxially connected to the crimping hole 1 through the deep drilled hole 2. The back-drilled hole 3 is located on the side away from the prepreg 6. The crimping hole 1 that needs to be back-drilled is back-drilled as required. Note that the back-drilling depth is the opposite of the conventional back-drilling method, so the back-drilling depth needs to be calculated and controlled in advance. The drill tip angle does not need to be calculated for the theoretical value. Then the sub-board is electroplated according to the copper thickness requirements.

[0036] On two adjacent sub-boards 7, a resist ring 4 coaxial with the crimping hole 1 is installed inside the laser hole. The sub-board 7 is fabricated according to the design. At the position of the crimping hole 1, additional staggered resist rings 4 are made on the upper and lower sub-boards 7. The inner diameter of one resist ring 4 is greater than or equal to the diameter of the crimping hole 1, and the inner diameter of the other resist ring 4 is greater than the diameter of the crimping hole 1. Figure 2 As shown, the two adhesive-resistant rings 4 form a nested structure, and the ring width of the adhesive-resistant rings 4 is set according to the thickness of the prepreg 6.

[0037] In one specific embodiment, the diameter of the crimp hole is 5 mil, and a resist ring with a ring width of 5 mil is installed on one daughterboard at a spacing of 5 mil; then a resist ring with a ring width of 5 mil is installed on another daughterboard at a spacing of 8 mil, to avoid the resist rings not being able to interlock due to misalignment between daughterboards.

[0038] If the inner diameter of one of the adhesive-resistant rings is equal to the diameter of the crimping hole, then the adhesive-resistant ring is the hole ring of the crimping hole.

[0039] In another specific embodiment, the diameter of the crimp hole is 5 mil, and a resist ring with an inner diameter of 5 mil and a ring width of 5 mil is installed on one daughterboard; a resist ring with a ring width of 5 mil is installed on another daughterboard at an 8 mil interval, to avoid the resist rings not being able to interlock due to misalignment between daughterboards.

[0040] Deep Drill Hole 2 refers to a design for high-speed holes on this board, forming a shorter stub. This stub is subject to control. If the board does not have a high-speed hole design, then Deep Drill Hole 2 is not required and is not a mandatory design.

[0041] Furthermore, the diameter D of the back drill hole 3 is greater than the diameter d1 of the deep drill hole 2, which is greater than the diameter d of the crimping hole 1; that is, D > d1 > d.

[0042] A glue storage tank 5 is provided around the sub-board 1 part opposite to the laser hole. The glue storage tanks 5 of adjacent sub-boards 1 are staggered. The glue storage tank 5 is made around the blind hole. Its function is to store the PP sheet glue from the blind hole during the pressing process and reduce the problem of glue flowing into the direction of the pressing hole 1.

[0043] In one specific embodiment, a resist groove is designed 5 mil away from the resist ring. The resist groove has a width of 5 mil and a depth of 5 mil. The specific resist reservoir can be laser-cut or the width of the resist groove can be adjusted and processed by controlled depth drilling. There are no restrictions here.

[0044] This embodiment prevents the PP adhesive from flowing out and clogging the press-fit holes by setting hole rings and adhesive-blocking rings around the press-fit holes and by staggering adhesive storage grooves on the sub-boards. This allows the use of high-flow-state prepregs as adhesive between sub-boards, extending the application of this type of press-fit blind hole PCB board to motherboards and cardboard, no longer limited to using low-flow-state prepregs as adhesive between sub-boards.

[0045] Example 2

[0046] This embodiment describes a method for manufacturing a PCB board with press-fit blind vias, specifically including the following steps:

[0047] Step 1: Drilling holes in sub-boards: A crimping hole 1 is provided on sub-board 7. Sub-board 7 has at least one crimping hole 1. This is not limited to one sub-board 7. It is also applicable to the design where both sub-boards 7 have crimping holes 1. Each sub-board 7 can have one or more crimping holes 1. The crimping holes 1 are drilled mechanically.

[0048] Sub-board 7 drills the crimping holes 1 that need to be metallized. The process here is not specifically limited depending on the requirements. If there are holes that need resin plugging, they can be drilled in stages: first, drill the holes requiring resin plugging for electroplating, and then drill the crimping holes 1. The crimping hole 1 is set according to the hole type. For non-high-speed holes (without back drilling), the diameter is set directly according to the required diameter. For high-speed holes (with back drilling), the diameter needs to be set in conjunction with the diameter of the back-drilled hole 3. For example, if the diameter of the back-drilled hole 3 is D, then the maximum diameter d of the crimping hole 1 is D-0.4mm. While meeting the requirements for subsequent hole plugging printing and back drilling capabilities, the diameter of the crimping hole 1 should be set as small as possible to avoid voids during subsequent hole plugging. For example, the diameter d of the crimping hole 1 is 0.4mm.

[0049] The daughterboard 7 may include multiple metal layers and a dielectric layer located between two adjacent metal layers. The metal layers include electrical components such as transistors, diodes, resistors, interconnects, and pins. The dielectric layer can achieve mutual insulation between lines and / or devices on different metal layers, preventing misconnection of lines and / or devices on two metal layers, which could lead to malfunction.

[0050] In the production or testing process of the circuit board, the crimp hole 1 enables signal transmission between the sub-board 7 and the component when the component's pin is inserted, without the need to solder the component to the sub-board, making it convenient to replace components and easy to operate.

[0051] Step 2, Burning holes in the prepreg: Laser holes are made on the prepreg 6 opposite to the crimping hole 1. The laser holes are made by burning holes with a PP laser. The purpose of burning holes with a PP laser is to pre-cure the PP around the crimping hole 1 to avoid the risk of adhesive flowing into the crimping hole 1. If there are other heating methods or the adhesive flow is controlled by increasing the opening of the prepreg 6, the corresponding holes are burned into the prepreg 6 by laser according to the position of the crimping hole 1. The purpose is to solve the risk of adhesive flowing into the hole.

[0052] Step 3, Sub-board Back Drilling: After drilling the sub-board 7, back drill the crimping hole 1 according to the preset back drilling depth to obtain the back drilled hole 3. Back drill the crimping hole 1 that needs back drilling as required. Note that the back drilling depth is the opposite of the conventional back drilling method, so the back drilling depth needs to be calculated and controlled in advance; the drill tip angle does not need to be calculated for the theoretical value.

[0053] Step 4: Sub-board Pattern Fabrication: Sub-board 7 is fabricated according to the design. At the crimping hole 1 position, additional staggered adhesive resistance rings 4 are made for the upper and lower sub-boards 7. The inner diameter of one adhesive resistance ring 4 is greater than or equal to the diameter of the crimping hole 1, and the inner diameter of the other adhesive resistance ring 4 is greater than the diameter of the crimping hole 1, while its outer diameter is smaller than the diameter of the laser hole. Figure 2 As shown, the two adhesive barrier rings 4 form a nested structure, and the ring width of the adhesive barrier ring 4 is set according to the thickness of the semi-cured sheet 6.

[0054] In one specific embodiment, the diameter of the crimp hole is 5 mil, and a resist ring with a ring width of 5 mil is installed on one daughterboard at a spacing of 5 mil; then a resist ring with a ring width of 5 mil is installed on another daughterboard at a spacing of 8 mil, to avoid the resist rings not being able to interlock due to misalignment between daughterboards.

[0055] If the inner diameter of one of the adhesive-resistant rings is equal to the diameter of the crimping hole, then the adhesive-resistant ring is the hole ring of the crimping hole.

[0056] In another specific embodiment, the diameter of the crimp hole is 5 mil, and a resist ring with an inner diameter of 5 mil and a ring width of 5 mil is installed on one daughterboard; a resist ring with a ring width of 5 mil is installed on another daughterboard at an 8 mil interval, to avoid the resist rings not being able to interlock due to misalignment between daughterboards.

[0057] Step 5: Perform pattern etching on the sub-board.

[0058] Step Six: Sub-board Deep Drilling: After the sub-board 7 is etched, the copper at the drill tip of the back-drilled hole 3 is drilled off using deep drilling. The depth is adjusted downwards from the depth of the crimping hole 1 after back drilling. Deep drilling is performed on the back-drilled hole 3 to break the copper at the drill tip, resulting in a deep drilled hole 2, forming a shorter stub. This stub is subject to control. This process is not mandatory; if the board does not have high-speed vias, this deep drilling process can be omitted.

[0059] Furthermore, the diameter D of the back drill hole 3 is greater than the diameter d1 of the deep drill hole 2, which is greater than the diameter d of the crimping hole 1; that is, D > d1 > d.

[0060] Step 7, Sub-board Surface Treatment: A glue storage tank 5 is provided around the sub-board 1 part opposite to the laser hole. The glue storage tanks 5 of adjacent sub-boards 1 are staggered. The glue storage tank 5 is made around the blind hole. Its function is to store the P-piece glue from the blind hole during the pressing process and reduce the problem of glue flowing into the direction of the crimping hole 1.

[0061] In one specific embodiment, a resist groove is designed 5 mil away from the resist ring. The resist groove has a width of 5 mil and a depth of 5 mil. The specific resist reservoir can be laser-cut or the width of the resist groove can be adjusted and processed by controlled depth drilling. There are no restrictions here.

[0062] Step 8, Sub-board lamination: Install the prepreg 6 between two sub-boards 7 and laminate them to obtain a crimped blind hole PCB board. The obtained crimped blind hole PCB board is then subjected to electroplating, pattern processing and surface treatment in sequence to obtain the processed crimped blind hole PCB board.

[0063] The embodiments of the present utility model have been described above with reference to the accompanying drawings. However, the present utility model is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present utility model without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present utility model.

Claims

1. A PCB board with press-fit blind vias, characterized in that, Includes at least two sub-boards and a prepreg installed between two adjacent sub-boards; The sub-board has crimping holes, and the prepreg opposite to the crimping holes has laser holes; the diameter of the laser holes is larger than the diameter of the crimping holes. An adhesive-resistant ring coaxial with the crimping hole is installed inside the laser hole. An adhesive storage groove is provided around the periphery of the sub-board portion opposite to the laser hole, and the adhesive storage grooves of adjacent sub-boards are staggered.

2. The press-fit blind via PCB board according to claim 1, characterized in that, One of the adhesive-resistant rings has an inner diameter greater than or equal to the diameter of the crimping hole, and the other adhesive-resistant ring has an inner diameter greater than the diameter of the crimping hole. The two adhesive-resistant rings form a nested structure. If the inner diameter of one of the adhesive-resistant rings is equal to the diameter of the crimping hole, then the adhesive-resistant ring is the hole ring of the crimping hole.

3. The press-fit blind via PCB board according to claim 1, characterized in that, The width of the adhesive barrier ring is set according to the thickness of the prepreg.

4. The press-fit blind via PCB board according to claim 1, characterized in that, This also includes back-drilled holes and deep-drilled holes; The back drill hole is coaxially connected to the crimping hole through a deep drill hole, and the back drill hole is located on the side away from the prepreg.

5. The press-fit blind via PCB board according to claim 4, characterized in that, The inner surface of the crimping hole is coated with an electroplated layer, and the inner surface of the back-drilled hole is coated with an electroplated layer.

6. The press-fit blind via PCB board according to claim 4, characterized in that, D>d1>d; where D represents the diameter of the back drill hole, d1 represents the diameter of the deep drill hole, and d represents the diameter of the crimping hole.

7. The press-fit blind via PCB board according to claim 6, characterized in that, The maximum diameter d of the crimping hole is D-0.4mm.

8. The press-fit blind via PCB board according to claim 1, characterized in that, Each sub-board includes multiple metal layers and a dielectric layer located between two adjacent metal layers.

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