Circuit board and electronic equipment
By setting multiple bottom surfaces and conductive layers in the blind groove of the circuit board, the problem of poor bonding force between the plating layer and the substrate at the bottom of the blind groove is solved, the bonding strength and reliability are improved, and the separation between the plating layer and the substrate at high temperature is prevented.
Patent Information
- Application Number
- CN202421801649.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-29
- Publication Date
- 2025-05-16
- Estimated Expiration
- 2034-07-29
AI Technical Summary
In the prior art, the bonding force between the metallized plating layer at the bottom of the blind groove and the circuit board substrate is poor, resulting in separation of the plating layer and the substrate under high temperature conditions.
By providing a blind groove bottom in the circuit board with at least two groove bottom surfaces, the contact area between the groove bottom and the dielectric layer is increased, and a conductive layer is provided in the dielectric layer to make the conductive layer come into contact with some groove bottom surfaces to improve the bonding force between the metal layer and the dielectric layer.
The bonding strength and bonding reliability of the metal layer and the dielectric layer in the blind groove are improved, the internal stress caused by external heat is reduced, and the separation of the plating layer and the substrate is prevented.
Smart Images
Figure CN222884851U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of circuit boards, in particular to a circuit board and an electronic device. Background Art
[0002] Printed circuit board (PCB) is a carrier that supports electronic components and is widely used in various electronic products. According to actual needs, blind grooves may be made on PCB to achieve functions such as snap-on installation, heat dissipation or signal shielding.
[0003] In blind slots prepared by existing processes, the bonding strength between the PCB substrate at the bottom of the blind slot and the metallized coating (hereinafter referred to as coating) on the surface of the blind slot is poor. Therefore, under high temperature conditions, internal stress is generated between the coating of the blind slot with a larger bottom area and the substrate, resulting in the separation of the coating and the substrate. How to solve the separation of the coating and the substrate has become an urgent problem to be solved. Utility Model Content
[0004] The utility model provides a circuit board and electronic equipment, which are used to improve the bonding strength and bonding reliability of a metal layer in a blind groove and a dielectric layer in a circuit board.
[0005] In a first aspect, the utility model provides a circuit board, comprising: at least two core boards, a dielectric layer located between two adjacent core boards, and at least one blind slot;
[0006] The blind slot includes a metal layer; the metal layer is in contact with the core board and the dielectric layer;
[0007] Along the thickness direction of the core plate, the bottom of the blind groove includes at least two bottom surfaces, and the angle between the planes where two adjacent bottom surfaces are located is α, 150°<α<180°;
[0008] The core board exposed on the surface of the circuit board is a surface core board, and at least one of the dielectric layers in contact with the surface core board includes a conductive layer. Along the thickness direction of the core board, the conductive layer contacts a portion of the bottom surface of the groove.
[0009] Optionally, along the thickness direction of the core board, the dielectric layer includes at least two conductive layers, and a vertical distance between two adjacent conductive layers is h;
[0010] Among them, 0mil<h<30mil.
[0011] Optionally, the conductive layer also contacts the sidewall of the blind groove.
[0012] Optionally, the conductive layer in contact with the bottom of the groove is a first conductive layer, and the conductive layer in contact with the sidewall of the blind groove is a second conductive layer. The thickness of the first conductive layer is H1, and the thickness of the second conductive layer is H2.
[0013] Among them, H1>H2.
[0014] Optionally, along a direction parallel to the plane where the core plate is located, the aperture of the blind slot is a, and the size of the conductive layer in contact with the same horizontal plane of the slot bottom surface is b;
[0015] Among them, b>a.
[0016] Optionally, the insulation distance between holes of the circuit board is I;
[0017] Among them, 12mil<ba<I.
[0018] Optionally, along a direction parallel to the plane where the core plate is located, a size of the conductive layer in contact with the same horizontal plane of the bottom surface of the groove is b1, and a size of the conductive layer in contact with the side wall is b2;
[0019] Among them, b1>b2.
[0020] Optionally, the groove bottom includes a first groove bottom surface and a second groove bottom surface;
[0021] The angle between the plane where the first groove bottom surface is located and the plane where the second groove bottom surface is located is 165°.
[0022] In a second aspect, the utility model further provides an electronic device, characterized in that it comprises the circuit board described in the first aspect.
[0023] The technical solution of the utility model increases the contact area between the bottom of the blind groove and the dielectric layer by setting the bottom of the blind groove to include at least two bottom surfaces, thereby improving the bonding force between the blind groove and the dielectric layer. By setting the angle α between the planes where two adjacent bottom surfaces are located to be greater than 150° and less than 180°, the bending degree between the two adjacent bottom surfaces is reduced to enhance the resistance of the bottom surface of the groove to the internal stress generated by the external thermal force. At the same time, a conductive layer is set in the dielectric layer, and the conductive layer is in contact with at least part of the bottom surface of the groove, so as to improve the metal bonding force between the metal layer on the bottom surface of the groove and the conductive layer, thereby improving the bonding force and bonding reliability between the metal layer and the dielectric layer in the blind groove. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, although the drawings described below are some specific embodiments of the utility model, for those skilled in the art, the basic concepts of the device structure, driving method and manufacturing method disclosed and suggested by the various embodiments of the utility model can be expanded and extended to other structures and drawings. Undoubtedly, these should all be within the scope of the claims of the utility model.
[0025] Figure 1 A schematic diagram of the structure of a circuit board provided in an embodiment of the utility model;
[0026] Figure 2 A schematic diagram of the structure of another circuit board provided in an embodiment of the utility model;
[0027] Figure 3 A schematic diagram of the structure of another circuit board provided in an embodiment of the utility model;
[0028] Figure 4 A schematic diagram of the structure of another circuit board provided in an embodiment of the utility model;
[0029] Figure 5 A schematic structural diagram of a circuit board provided in an embodiment of the utility model. DETAILED DESCRIPTION
[0030] In order to make the purpose, technical solution and advantages of the utility model clearer, the following will refer to the drawings in the embodiments of the utility model to clearly and completely describe the technical solution of the utility model through the implementation method. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the basic concepts disclosed and suggested by the embodiments of the utility model, all other embodiments obtained by those skilled in the art are within the scope of protection of the utility model.
[0031] Figure 1 A schematic diagram of the structure of a circuit board provided in an embodiment of the utility model is shown in FIG. Figure 1As shown, the circuit board 100 includes: at least two core boards 10, a dielectric layer 20 located between two adjacent core boards 10, and at least one blind slot 30; the blind slot 30 includes a metal layer 33; the metal layer 33 contacts the core board 10 and the dielectric layer 20. Along the thickness direction Z of the core board 10, the bottom of the blind slot 30 includes at least two slot bottom surfaces 31, and the angle between the planes where the two adjacent slot bottom surfaces 31 are located is α, 150°<α<180°; the core board 10 exposed on the surface of the circuit board 100 is the surface core board 11, and the dielectric layer 20 contacting the surface core board 11 includes a conductive layer 21; along the thickness direction Z of the core board 10, the conductive layer 21 contacts part of the slot bottom surface 31.
[0032] Among them, the core board 10 includes a copper-clad board, etc., and circuits can be prepared on the core board 10. The dielectric layer 20 can realize mutual insulation between circuits and / or devices of different core boards 10 in the circuit board 100, and prevent the circuits and / or devices between two layers of core boards 10 from being misconnected, which may cause abnormal operation of the PCB, etc. The material of the dielectric layer 20 can be an insulating material such as epoxy resin. The conductive layer 21 includes conductive materials such as copper, and the metal layer 33 in the blind groove 30 includes conductive materials such as copper. The shape and size of the blind groove 30 can be designed according to actual needs. For example, the shape of the blind groove 30 is a rectangular parallelepiped, and it can also be other shapes, which are not specifically limited here.
[0033] Specifically, by setting the blind groove 30 to include two or more groove bottom surfaces 31, the contact area between the groove bottom of the blind groove 30 and the dielectric layer 20 is increased, and the bonding strength between the groove bottom and the dielectric layer 20 is improved. If the angle α between the planes where two adjacent groove bottom surfaces 31 are located is less than 150° or greater than 180°, the bending degree between the two adjacent groove bottom surfaces 31 is relatively large, and the internal stress generated by the adjacent groove bottom surfaces 31 under the influence of external heat easily separates the metal layer 33 located on the groove bottom surface 31 from the dielectric layer 20. Therefore, in this embodiment, the angle α between the planes where two adjacent groove bottom surfaces 31 are located is set to be greater than 150° and less than 180°, so that the bending degree between the two adjacent groove bottom surfaces 31 is relatively gentle, so as to resist the internal stress generated by heat, and improve the bonding reliability of the metal layer 33 on the groove bottom surface 31 and the dielectric layer 20. In addition, by arranging the conductive layer 21 in the dielectric layer 20 and making the conductive layer 21 contact with part of the groove bottom surface 31, that is, the conductive layer 21 contacts with part of the metal layer 33 located at the groove bottom surface 31, since the conductive layer 21 and the metal layer 33 are conductive, a metal bonding bond is formed between metal and metal or between metal and conductive material to enhance the bonding force between the conductive layer 21 and the metal layer 33, and to enhance the bonding force between the metal layer 33 at the groove bottom surface 31 and the conductive layer 21 located at the dielectric layer 20. In this way, by increasing the contact area between the groove bottom surface 31 and the dielectric layer 20, and by arranging the conductive layer 21 in the dielectric layer 20 to contact with the groove bottom surface 31, the bonding strength and bonding reliability between the metal layer 33 and the dielectric layer 20 in the blind groove 30 are enhanced.
[0034] Understandably, Figure 1 In the description, only the circuit board 100 including two layers of core boards 10 is used as an example. The number of core boards 10 provided in the circuit board 100 may be other. Figure 2 A schematic diagram of the structure of another circuit board provided in an embodiment of the utility model is shown as follows: Figure 2 As shown, the circuit board 100 includes four layers of core boards 10, the core board exposed on the surface of the circuit board 100 is the surface core board 11, the core board located inside the circuit board 100 is the internal core board 12, and a conductive layer 21 is provided in the dielectric layer 20 in contact with the surface core board 11. The blind groove 30 is usually provided in the surface core board 11 and the dielectric layer 20 in contact with the surface core board 11, so the conductive layer 21 is only provided in the dielectric layer 20 in contact with the surface core board 11 to improve the connection reliability between the metal layer 33 in the blind groove 30 and the dielectric layer 20. The conductive layer 21 can be provided in the dielectric layer 20 between the internal core boards 12 according to actual needs, which is not specifically limited here. In addition, the blind groove 30 can be provided only on one side of the surface core board 11 of the circuit board 100, or the blind groove 30 can be provided on both sides of the surface core boards 11 of the circuit board 100, which can be provided according to actual needs, which is not specifically limited here.
[0035] The technical solution of the utility model increases the contact area between the bottom of the blind groove and the dielectric layer by setting the bottom of the blind groove to include at least two bottom surfaces, thereby improving the bonding force between the blind groove and the dielectric layer. By setting the angle α between the planes where two adjacent bottom surfaces are located to be greater than 150° and less than 180°, the bending degree between the two adjacent bottom surfaces is reduced to enhance the resistance of the bottom surface of the groove to the internal stress generated by the external thermal force. At the same time, a conductive layer is set in the dielectric layer, and the conductive layer is in contact with at least part of the bottom surface of the groove, so as to improve the metal bonding force between the metal layer on the bottom surface of the groove and the conductive layer, thereby improving the bonding force and bonding reliability between the metal layer and the dielectric layer in the blind groove.
[0036] It should be noted that, on the basis that the bottom of the blind groove 30 includes at least two groove bottom surfaces 31, the number of the groove bottom surfaces 31 can be set according to actual needs, and further reference is made to Figure 1 The bottom of the blind groove 30 includes four bottom surfaces 31, and the angles between the planes where two adjacent bottom surfaces 31 are located are α1, α2, and α3, respectively. In the range of α1, α2, and α3 being greater than 150° and less than 180°, the angles of α1, α2, and α3 can be the same or different, and can be set according to actual needs, and are not specifically limited here. For ease of description, the following embodiments are all described by taking the bottom of the blind groove 30 including two bottom surfaces 31 as an example.
[0037] Optional, Figure 3 A schematic diagram of the structure of another circuit board provided in an embodiment of the utility model is shown as follows: Figure 3 As shown, along the thickness direction Z of the core board 10 , the dielectric layer 20 includes at least two conductive layers 21 , and the vertical distance between two adjacent conductive layers 21 is h; wherein 0 mil<h<30 mil.
[0038] Specifically, by setting the dielectric layer 20 to include two or more conductive layers 21, the vertical distance h between two adjacent conductive layers 21 is between 0 mil and 30 mil, so as to increase the number of conductive layers 21 in contact with the metal layer 33 of the groove bottom surface 31, increase the metal bonding strength formed between the metal layer 33 of the groove bottom surface 31 and the conductive layer 21, and improve the bonding reliability between the groove bottom surface 31 and the dielectric layer 20.
[0039] Optional, Figure 4 A schematic diagram of the structure of another circuit board provided in an embodiment of the utility model is shown as follows: Figure 4 As shown, the conductive layer 21 is also in contact with the sidewall of the blind trench 30 .
[0040] Specifically, in addition to being in contact with a portion of the bottom surface 31 of the groove, the conductive layer 21 in the dielectric layer 20 is also in contact with the side wall of the blind groove, and the metal layer 33 located on the side wall forms a metal bonding bond with the conductive layer 21 to enhance the bonding force between the metal layer 33 on the side wall and the dielectric layer 20, and to enhance the bonding force between the metal layer 33 on the side wall and the conductive layer 21 located on the dielectric layer 20. In this way, by providing the conductive layer 21 in contact with the bottom surface 31 of the groove and the conductive layer 21 in contact with the side wall of the blind groove 30 in the dielectric layer 20, the bonding force between the entire blind groove 30 and the dielectric layer 20 is enhanced, and the bonding strength and bonding reliability between the metal layer 33 in the blind groove 30 and the dielectric layer 20 are enhanced.
[0041] It is understandable that the thickness of the conductive layer 21 in contact with the bottom of the groove and the conductive layer 21 in contact with the side wall can be equal, so that when preparing each conductive layer 21 in the dielectric layer 20, the same preparation parameters and equipment can be used to prepare the conductive layer 21, thereby improving the preparation efficiency of the circuit board. Figure 4 The conductive layer 21 in contact with the bottom of the groove is the first conductive layer 211, and the conductive layer 21 in contact with the side wall of the blind groove is the second conductive layer 212. The thickness of the first conductive layer 211 is H1, and the thickness of the second conductive layer 212 is H2; wherein H1>H2.
[0042] Specifically, since the plane where the second conductive layer 212 is located is perpendicular to the plane where the metal layer 33 of the side wall is located, under the action of external heat, the second conductive layer 212 can provide the metal layer 33 of the side wall with a force parallel to the plane where the second conductive layer 212 is located, thereby improving the bonding reliability between the metal layer 33 of the side wall and the dielectric layer 20. Since the angle between the plane where the metal layer 33 of the bottom of the groove is located and the plane where the first conductive layer 211 is located is an acute angle, the force provided by the first conductive layer 211 to the metal layer 33 of the bottom of the groove to resist the thermal internal stress is relatively small. Therefore, in order to improve the bonding force between the metal layer 33 of the bottom of the groove and the dielectric layer 20 in the blind groove 30, the thickness H1 of the first conductive layer 211 in contact with the bottom of the groove is greater than the thickness H2 of the second conductive layer 212 in contact with the side wall of the blind groove, so as to improve the metal bonding force between the metal layer 33 of the bottom of the groove and the first conductive layer 211, thereby improving the bonding reliability between the metal layer 33 of the bottom of the groove and the dielectric layer 20, and improving the bonding reliability between the blind groove as a whole and the dielectric layer 20.
[0043] Optional, continue to refer to Figure 4 , along the direction X parallel to the plane where the core plate 10 is located, the aperture of the blind groove 30 is a, and the size of the conductive layer 21 in contact with the same horizontal plane of the groove bottom surface 31 is b; wherein, b>a.
[0044] Specifically, by setting the size b of the conductive layer 21 in contact with the same horizontal plane as the groove bottom surface 31 to be larger than the aperture a of the blind groove 30, after the blind groove 30 is drilled out by a drilling device, the conductive layer 21 overlapping with the blind groove 30 is drilled away, and the portion of the conductive layer 21 larger than the aperture a is retained, thereby ensuring that the conductive layer 21 in the dielectric layer 20 can contact the metal layer 33 on the groove bottom surface 31, thereby improving the bonding reliability of the blind groove 30 and the dielectric layer 20.
[0045] Optional, continue to refer to Figure 4 , the insulation distance between holes of the circuit board 100 is I; 12mil<ba<I.
[0046] Specifically, the inter-hole insulation distance indicates the minimum safe distance for maintaining insulation between two adjacent holes. If the difference between the size b of the conductive layer 21 in contact with the same horizontal plane of the groove bottom surface 31 and the aperture a of the blind groove 30 is greater than the inter-hole insulation distance I, the metal layer 33 in the blind groove 30 may be electrically connected to other adjacent blind grooves or other through holes through the conductive layer 21, affecting the working reliability of the circuit board 100. Therefore, in this embodiment, the difference between the size b of the conductive layer 21 in contact with the same horizontal plane of the groove bottom surface 31 and the aperture a of the blind groove 30 is set to be less than the inter-hole insulation distance I, so as to avoid the blind groove 30 being electrically connected to other through holes through the conductive layer 21, thereby improving the working reliability of the circuit board. In addition, on the basis that the difference between the size b of the conductive layer 21 in contact with the same horizontal plane of the groove bottom surface 31 and the aperture a of the blind groove 30 is less than the inter-hole insulation distance I, the difference between the size b of the conductive layer 21 in contact with the same horizontal plane of the groove bottom surface 31 and the aperture a of the blind groove 30 is made greater than 12 mil, so that the conductive layer 21 in contact with the groove bottom surface 31 has a certain size, so that under the action of external heat, the conductive layer 21 can provide metal bonding force for the blind groove 30 to resist the internal stress generated under the action of heat, thereby improving the bonding reliability of the blind groove 30.
[0047] Understandably, Figure 4 FIG. 1 shows a circuit board 100 in which the size of the conductive layer 21 in contact with the same horizontal plane of the groove bottom surface 31 and the size of the conductive layer 21 in contact with the side wall are both b. In an optional embodiment, Figure 5 A schematic diagram of the structure of a circuit board provided in an embodiment of the utility model is shown in FIG. Figure 5 As shown, along the direction X parallel to the plane where the core plate 10 is located, the size of the conductive layer 21 in contact with the same horizontal plane of the groove bottom surface 31 is b1, and the size of the conductive layer 21 in contact with the side wall is b2; wherein, b1>b2.
[0048] Specifically, by setting the size b1 of the conductive layer 21 in contact with the same horizontal plane of the groove bottom surface 31 to be larger than the size b2 of the conductive layer 21 in contact with the side wall, the conductive layer 21 in contact with the same horizontal plane of the groove bottom surface 31 can provide a larger metal bonding force for the metal layer 33 of the groove bottom surface 31, thereby improving the bonding force between the metal layer 33 of the groove bottom surface 31 and the dielectric layer 20, and improving the bonding reliability between the blind groove 30 and the dielectric layer 20.
[0049] Optional, reference Figure 2, the bottom of the groove includes a first groove bottom surface 311 and a second groove bottom surface 312; the angle between the plane where the first groove bottom surface 311 is located and the plane where the second groove bottom surface 312 is located is 165°. In this way, a 165° drill can be used to drill out the blind groove 30 having the first groove bottom surface 311 and the second groove bottom surface 312, and the angle between the plane where the first groove bottom surface 311 is located and the plane where the second groove bottom surface 312 is located is 165°, thereby improving the preparation efficiency and improving the bonding strength and bonding reliability between the metal layer 33 and the dielectric layer 20 of the first groove bottom surface 311 and the second groove bottom surface 312.
[0050] It should be noted that the process for preparing the circuit board 100 provided by the utility model is as follows: after cutting, the pattern of the core board and the conductive layer of the dielectric layer are prepared, the core boards and the dielectric layers are laminated, blind grooves are drilled out using a drill and other equipment, the burrs in the blind grooves are removed, the laminated boards are heated and dried after being pressed, the board surface is electroplated after copper plating, the outer layer pattern of the laminated boards is prepared, and then it is dried. The heating temperature in the drying conditions is 135° and the heating time is 2 hours to remove the moisture absorbed in the side walls and bottom of the blind groove, reduce the stress caused by the expansion of water vapor when subjected to external thermal shock, and then perform reflow soldering test and other steps.
[0051] Based on the same utility model concept, the embodiment of the utility model provides an electronic device, which includes the circuit board provided by any embodiment of the utility model, so the electronic device has the technical features and beneficial effects of the circuit board provided by the utility model, and the same can be referred to the above description. In an optional embodiment, the electronic device can be a mobile phone, a computer, etc.
[0052] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims
1. A circuit board, characterized in that: include: At least two core plates, a dielectric layer between two adjacent core plates, and at least one blind slot; The blind slot includes a metal layer; the metal layer is in contact with the core board and the dielectric layer; Along the thickness direction of the core plate, the bottom of the blind groove includes at least two bottom surfaces, and the angle between the planes where two adjacent bottom surfaces are located is α, 150°<α<180°; The core board exposed on the surface of the circuit board is a surface core board, and at least one of the dielectric layers in contact with the surface core board includes a conductive layer. Along the thickness direction of the core board, the conductive layer contacts a portion of the bottom surface of the groove.
2. The circuit board according to claim 1, characterized in that: Along the thickness direction of the core board, the dielectric layer includes at least two conductive layers, and the vertical distance between two adjacent conductive layers is h; Among them, 0mil<h<30mil.
3. The circuit board according to claim 1, characterized in that: The conductive layer also contacts the sidewall of the blind trench.
4. The circuit board according to claim 3, characterized in that: The conductive layer in contact with the bottom of the groove is a first conductive layer, and the conductive layer in contact with the sidewall of the blind groove is a second conductive layer. The thickness of the first conductive layer is H1, and the thickness of the second conductive layer is H2; Among them, H1>H2.
5. The circuit board according to claim 1, characterized in that: Along the direction parallel to the plane where the core plate is located, the aperture of the blind slot is a, and the size of the conductive layer in contact with the same horizontal plane of the slot bottom surface is b; Among them, b>a.
6. The circuit board according to claim 5, characterized in that: The insulation distance between holes of the circuit board is I; Among them, 12mil<ba<I.
7. The circuit board according to claim 3, characterized in that: Along the direction parallel to the plane where the core plate is located, the size of the conductive layer in contact with the same horizontal plane of the bottom surface of the groove is b1, and the size of the conductive layer in contact with the side wall is b2; Among them, b1>b2.
8. The circuit board according to claim 1, characterized in that: The groove bottom includes a first groove bottom surface and a second groove bottom surface; The angle between the plane where the first groove bottom surface is located and the plane where the second groove bottom surface is located is 165°.
9. An electronic device, characterized in that: A circuit board comprising any one of claims 1 to 8.