Circuit board
Through the metal frame, the conductive part is placed in the concave surface through the connection pad and the concave surface is formed, which solves the problem of spatial layout and connection stability of the circuit board in the fine-pitch product, and achieves a tighter bonding force and stability to prevent overflowing tin bridges. , improves the coplanarity and anti-position bias capability of the module structure.
Patent Information
- Application Number
- CN202420933829.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-30
- Publication Date
- 2025-01-14
- Estimated Expiration
- 2034-04-30
AI Technical Summary
Existing circuit boards have challenges in spatial layout and connection stability, especially in fine-pitch products. Traditional BGA parts are prone to bubbles, poor reliability, poor coplanarity and biased positioning problems.
A metal frame is used to penetrate the connecting pad, and a concave surface is formed at the connection end of the metal frame, and the conductive part is placed in the concave surface, so as to achieve the fixed and electrical connection between the module structure and the circuit substrate, reduce the size and spacing of the connection pads, and improve space utilization. Rate and electrical connection stability.
A tighter connection bonding force is achieved, the stability of electrical connections is enhanced, the overflow tin bridge is prevented, and the coplanarity and anti-position biasing ability of the module structure are improved.
Smart Images
Figure CN222356601U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of circuit boards, and in particular to a circuit board. Background Art
[0002] With the advancement of technology, people have higher and higher requirements for electronic products such as mobile phones, tablets, and laptops. In order to meet market demand, the circuit boards in electronic products need to continue to develop in the direction of short, small, light, and thin. The more functions an electronic product has, the more parts there will be on the circuit board, which causes great trouble for the spatial layout of the circuit board. Existing circuit boards are in urgent need of improvement in terms of optimizing layout and saving space. Utility Model Content
[0003] In view of this, in order to solve at least one of the above problems, it is necessary for the present application to provide a circuit board.
[0004] An embodiment of the present application provides a circuit board, which includes: a circuit substrate, multiple metal frames and a first module structure, the circuit substrate includes a first circuit layer located on the outside, the first circuit layer includes multiple first connection pads, the circuit substrate has multiple mounting holes corresponding to the first connection pads, each of the mounting holes penetrates the corresponding first connection pad; each of the metal frames is located in one of the mounting holes, the metal frame includes a frame body and a first connection end provided at one end of the frame body, the frame body is located in the mounting hole, the first connection end is electrically connected to the first connection pad and extends out of the mounting hole, the first connection end includes a first concave surface that is recessed toward one side of the frame body; the first module structure is located on a side of the circuit substrate where the first circuit layer is provided, the first module structure includes a first element and multiple first conductive parts located in the first element close to the first circuit layer, each of the first conductive parts is located in a corresponding first concave surface.
[0005] In some possible embodiments, the circuit substrate further includes a second circuit layer, the second circuit layer includes a plurality of second connection pads corresponding to the first connection pads, the second connection pads are exposed by the mounting holes, and the frame is electrically connected to the second connection pads.
[0006] In some possible embodiments, a conductive adhesive layer is provided between the frame and the second connection pad, the mounting hole partially extends into the second connection pad to form a groove on the second connection pad, and the conductive adhesive layer is located in the groove.
[0007] In some possible embodiments, the conductive adhesive layer further extends between the frame and the wall of the mounting hole.
[0008] In some possible embodiments, the first connection end includes a first end close to the frame and a second end away from the frame, the outer diameter of the first connection end along the extension direction of the circuit substrate increases sequentially from the first end to the second end, the mounting hole includes a first hole corresponding to the first connection pad, the first connection end is located in the first hole and extends out of the first hole, and the first hole has a concave structure that matches the outer surface of the first connection end.
[0009] In some possible embodiments, the frame has a hollow cavity in which a heat-conducting medium or a cooling medium is disposed; or, the frame is a hollow structure in which an adhesive is disposed, and the adhesive passes through the frame and is connected to the hole wall of the mounting hole.
[0010] In some possible embodiments, the metal frame is made of gold, silver, copper or aluminum.
[0011] In some possible embodiments, a plurality of microstructures are disposed on the first concave surface, and the microstructures are protrusions, pits, or grids.
[0012] In some possible embodiments, the circuit substrate also includes a second circuit layer stacked with the first circuit layer, the second circuit layer includes a plurality of second connection pads corresponding to the first connection pads, the mounting hole also penetrates the corresponding second connection pads, the metal frame 4 also includes a second connection end arranged on the frame away from the first connection end, the second connection end is electrically connected to the second connection pad and extends out of the mounting hole, the second connection end includes a second concave surface recessed toward the first connection end, the circuit board also includes a second module structure located on the side of the second circuit layer away from the first circuit layer, the second module structure includes a second element and a plurality of second conductive parts located on the second element close to the second circuit layer, each of the second conductive parts is located in a corresponding second concave surface.
[0013] In some possible embodiments, a heat dissipation layer is provided between the first module structure and the first circuit layer, and a material of the heat dissipation layer is an insulating thermally conductive resin.
[0014] Compared with the prior art, the circuit board provided in the embodiment of the present application adopts a metal frame to penetrate the first connection pad, and forms a first concave surface at the first connection end of the metal frame, and places the first conductive part in the first concave surface, and then realizes the fixation and electrical connection between the first module structure and the circuit substrate through the metal frame. The first connection pad does not need to be directly provided with a via, and the size and spacing of the first connection pad can be reduced, which is conducive to the production of fine-pitch products and improves the space utilization rate of the circuit board. At the same time, the first connection end can be tightly combined with the first conductive part and the first connection pad, and the bonding force is strong, and the stability of the electrical connection is improved. The recessed design of the first concave surface can also effectively prevent bridging of overflow tin. Moreover, the size of the metal frame is easy to control, the size of the first conductive part is roughly the same as the size of the first concave surface, and the size uniformity is good, which can improve the coplanarity of the first module structure. At the same time, through the support of the metal frame, the first module structure is not easy to be offset. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 A schematic diagram of the structure of a circuit board provided in one embodiment of the present application.
[0016] Figure 2 A schematic diagram of the structure of a circuit board provided in another embodiment of the present application.
[0017] Figure 3 for Figure 1 Schematic diagram of the structure of the metal frame shown.
[0018] Figure 4 for Figure 3 A schematic structural diagram of the first connecting end in the metal frame is shown.
[0019] Figure 5 for Figure 1 A top view of the circuit board after the metal frame is installed.
[0020] Figure 6 for Figure 1 A schematic structural diagram of a microstructure disposed on the first connecting structure of a metal frame is shown.
[0021] Figure 7 for Figure 6 A schematic structural diagram of the first connecting end in the metal frame is shown.
[0022] Figure 8 for Figure 1 A top view of a metal frame with microstructures on a mid-circuit substrate.
[0023] Fig. 9 A schematic diagram of the structure of a circuit board provided in yet another embodiment of the present application.
[0024] Main component symbols
[0025] Circuit board 100
[0026] Circuit board 10
[0027] Insulation layer 1
[0028] First surface 11
[0029] Second surface 12
[0030] Second hole 1 3
[0031] First circuit layer 2
[0032] First Line 22
[0033] First connection pad 21
[0034] First hole 23
[0035] Second circuit layer 3
[0036] Second line 3 1
[0037] Second connection pad 32
[0038] Groove 33
[0039] Metal rack 4
[0040] Frame 41
[0041] First connection terminal 42
[0042] First End 421
[0043] Second end 422
[0044] First concave surface 43
[0045] Cavity 44
[0046] Microstructure 45
[0047] The second connection terminal 46
[0048] Second concave surface 47
[0049] First module structure 5
[0050] First element 51
[0051] The first conductive portion 52
[0052] Conductive adhesive layer 6
[0053] Filling medium 7
[0054] Heat dissipation layer 8
[0055] Second module structure 9
[0056] Second element 91
[0057] The second conductive portion 92
[0058] Extension direction a
[0059] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION
[0060] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.
[0061] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. When an element is considered to be "set on" another element, it may be directly set on the other element or there may be a central element at the same time.
[0062] In the traditional electrical connection between BGA parts and circuit substrates, the connection pads on the circuit substrate are usually connected to the lower circuit layer through vias. The specific method is to first form blind holes on the connection pads, then print solder paste, and then mount the BGA parts through SMT. However, in this way, bubbles often appear in SMT, resulting in poor reliability; when blind holes are formed on the connection pads, space is occupied and the spacing is difficult to reduce; the coplanarity of printed solder paste is poor, resulting in poor flatness of BGA parts and poor electrical connection problems; in addition, for fine pitch devices, BGA parts are easily misaligned.
[0063] To solve the above problems, please refer to Figure 1As shown, an embodiment of the present application provides a circuit board 100, which includes: a circuit substrate 10, a plurality of metal frames 4, and a first module structure 5. The circuit substrate 10 includes a first circuit layer 2 located on the outside, and the first circuit layer 2 includes a plurality of first connection pads 21. The circuit substrate 10 has a plurality of mounting holes 101 corresponding to the first connection pads 21, and each mounting hole 101 penetrates the corresponding first connection pad 21. Each metal frame 20 is located in a mounting hole 101, and the metal frame 4 includes a frame body 41 and a first connection end 42 provided at one end of the frame body 41, and the frame body 41 is located in the mounting hole 101, and the first connection end 42 is electrically connected to the first connection pad 21 and extends out of the mounting hole 101. The first connection end 42 includes a first concave surface 43 that is recessed toward one side of the frame body 41. The first module structure 5 is located on a side of the circuit substrate 10 where the first circuit layer 2 is set. The first module structure 5 includes a first component 51 and a plurality of first conductive parts 52 located on a side of the first component 51 close to the first circuit layer 2. Each first conductive part 52 is located in a corresponding first concave surface 43, so that the first package body 51 is electrically connected to the first circuit layer 2 through the first conductive part 52 and the metal frame 4.
[0064] The circuit substrate 10 also includes a second circuit layer 3 stacked with the first circuit layer 2, and the frame 41 of the metal frame 4 can be electrically connected to the second circuit layer 3, so as to achieve the purpose of up and down or inside and outside conduction, without the need to set additional vias, which is conducive to saving space of the circuit board 100 and improving wiring density. The circuit substrate 10 can be a double-sided board, and the first circuit layer 2 and the second circuit layer 3 are both outer circuits. It can be understood that the circuit substrate can also be a multi-layer board, and the second circuit layer can be an outer circuit or an inner circuit. In some embodiments, the first circuit layer 2 also includes a first circuit 22, and the first connection pad 21 is electrically connected to the first circuit 22.
[0065] The circuit substrate 10 further includes an insulating layer 1, the insulating layer 1 includes a first surface 11 and a second surface 12 arranged opposite to each other, the first circuit layer 2 is located on the first surface 11, and the second circuit layer 3 is located on the second surface 12.
[0066] In some embodiments, the material of the insulating layer 1 may be polyimide (PI), liquid crystal polymer (LCP), polytetrafluoroethylene (PTFE), etc. In this embodiment, the material of the insulating layer 1 may be polyimide.
[0067] The mounting hole 101 may include a first hole 23 corresponding to the first connecting pad 21, the first connecting end 42 is located in the first hole 23, and the first connecting end 42 extends out of the first hole 23, that is, the first connecting end 42 exceeds the surface of the first connecting pad 21, so that the first connecting end 42 can fully contact with the first connecting pad 21, thereby improving the stability of the electrical connection.
[0068] In some embodiments, the first connection end 42 includes a first end 421 close to the frame 41 and a second end 422 away from the frame 41. The outer diameter of the first connection end 42 along the extension direction a of the circuit substrate 10 increases successively from the first end 421 to the second end 422, so that the outer surface of the first connection end 42 forms a curved structure protruding toward one side of the frame 41, and the corresponding first hole 23 has a concave surface matching the first connection end 42. In this way, when the metal frame 4 is embedded in the mounting hole 101, the outer surface of the first connection end 42 abuts against the inner wall of the first hole 23. When the first conductive portion 52 is placed in the first concave surface 43, the first connection end 42 will apply a downward pressure to the first connection pad 21, so that the first conductive portion 52, the first connection end 42 and the first connection pad 21 are connected more tightly, and the electrical connection stability is stronger.
[0069] The mounting hole 101 further includes a second hole 13 corresponding to the insulating layer 1, and the frame 41 is located in the second hole 13. The second circuit layer 3 includes a second circuit 31 and a plurality of second connection pads 32, each second connection pad 32 corresponds to a first connection pad 21 and a mounting hole 101, and the first connection pad 21 is exposed by the corresponding mounting hole 101, so that the frame 41 of the metal frame 4 is electrically connected to the second connection pad 32. Specifically, the end of the frame 41 away from the first connection end 42 is electrically connected to the second connection pad 32.
[0070] In some embodiments, a conductive adhesive layer 6 is disposed between the frame 41 and the second connection pad 32 . By disposing the conductive adhesive layer 6 , the gap between the frame 41 and the second connection pad 32 can be reduced, thereby improving the stability of the electrical connection between the metal frame 41 and the second connection pad 32 .
[0071] In some embodiments, the mounting hole 101 extends to a portion of the second connection pad 32 to form a groove 33 on the second connection pad 32, and the conductive adhesive layer 6 can be located in the groove 33. The formation of the groove 33 is conducive to fully removing the insulating layer 1 to expose the second connection pad 32, and the groove 33 can also increase the contact area between the conductive adhesive layer 6 and the second connection pad 32, thereby improving the stability of the electrical connection.
[0072] Please refer to Figure 2, a conductive adhesive layer 6 may also be provided between the frame body 41 and the hole wall of the mounting hole 101. Specifically, a conductive adhesive layer 6 is provided between the frame body 41 and the hole wall of the second hole 13, so that the metal frame 4 is further firmly fixed in the mounting hole 101, so as to further improve the connection stability between the metal frame 4 and the first connection pad 21 and the second connection pad 32. It can be understood that the conductive adhesive layer 6 between the frame body 41 and the hole wall of the second hole 13 can be formed by extending the conductive adhesive layer 6 on the second connection pad 32 into the second hole 13. That is, during molding, a suitable conductive adhesive is filled into the mounting hole 101, and the conductive adhesive can be squeezed into the second hole 13 after the metal frame 4 is installed.
[0073] In some embodiments, the conductive adhesive layer 6 is mainly formed by curing a conductive adhesive, which is mainly composed of an adhesive (such as an adhesive system such as epoxy resin, silicone resin, polyimide resin, phenolic resin, polyurethane, acrylic resin, etc.), conductive particles (powders of gold, silver, copper, aluminum, zinc, iron, nickel, graphite and some conductive compounds), dispersing additives, additives, etc. The conductive adhesive can be a homotropic conductive adhesive or anisotropic conductive adhesive, etc.
[0074] The first module structure 5 may be, for example, a BGA component, and the first conductive portion 52 may be formed after the solder paste is solidified.
[0075] The metal frame 4 can be a metal component formed of pure metals such as gold, silver, copper, and aluminum. It can be understood that it can also be an alloy component formed of the aforementioned metals. Such metal components are more easily combined with tin (the material forming the first conductive portion 52) to form an IMC alloy layer such as Cu5Sn6, and the bonding force is stronger. In addition, the size of the metal frame 4 can be made smaller to meet the purpose of fine pitch of the product (i.e., Fine Pitch).
[0076] The frame 41 may have a hollow cavity 44, in which a filling medium 7 is provided. The filling medium 7 may be a heat-conducting medium to enhance the heat extraction from the circuit substrate 10. The filling medium 7 may also be a cooling medium, such as a cooling medium material with a high specific heat capacity for cooling the parts and the circuit substrate 10, and the cooling medium may be a fluoride or a high molecular polymer for cooling. By designing a sealed and hollow cavity 44 in the frame 41, the heat dissipation sealing is better, and the filling medium 7 will not overflow the frame 41, so as not to affect the conduction between the metal frame 4 and the circuit substrate 10.
[0077] It is understandable that in other embodiments, the frame 41 can also be a hollow structure, that is, the cavity 44 is connected to the second hole 13, and an adhesive can be arranged in the hollow structure. The adhesive can pass through the frame 41 and connect with the hole wall of the mounting hole 101, thereby improving the connection stability between the metal frame 4 and the circuit substrate 10.
[0078] The first concave surface 43 may be a spherical surface, a conical surface, a trapezoidal surface, etc., and may be designed according to the size and density of the first connection pad 21. Figures 3 to 5 As shown, the first concave surface 43 may be a spherical curved surface. It is understandable that in order to fit more closely with the first concave surface 43, the first conductive portion 52 may be designed to be spherical, conical, trapezoidal, rectangular, etc. according to the actual shape of the first concave surface 43.
[0079] In some embodiments, Figures 6 to 8 As shown, a plurality of microstructures 45 may be provided on the first concave surface 43, and the microstructures 45 may extend into the first conductive portion 52 or the first conductive portion 52 may extend into the microstructures 45, thereby improving the bonding force between the first conductive portion 52 and the first connecting end 42 of the metal frame 4. Specifically, the microstructures 45 may be structures such as protrusions (such as convex points, convex strips, etc.), pits, or grids, so as to increase the bonding force between the first conductive portion 52 and the first concave surface 43.
[0080] Please refer again Figure 1 A heat dissipation layer 8 is provided between the first module structure 5 and the first circuit layer 2. The heat dissipation layer 8 may be made of insulating thermally conductive resin, which can improve the connection stability between the first conductive portion 52 and the first connecting end 42 and further enhance heat dissipation.
[0081] It is understandable that the circuit board 100 can be used as an independent circuit board, or can be embedded or designed into other packaging structures as a component. It is also understandable that when the circuit board 100 is connected to other circuit boards, wire bonding or conductive adhesive (ACF) can be used.
[0082] The circuit board 100 provided in the embodiment of the present application, by using a metal frame 4 to penetrate the first connection pad 21, and forming a first concave surface 43 at the first connection end 42 of the metal frame 4, the first conductive part 52 is placed in the first concave surface 43, and then the first module structure 5 is fixed and electrically connected to the circuit substrate 10 through the metal frame 4. In this way, the first connection pad 21 does not need to be directly provided with a via, and the size and spacing of the first connection pad 21 can be reduced, which is conducive to the production of fine-pitch products and improves the space utilization of the circuit board 100. At the same time, the first connection end 42 can be tightly combined with the first conductive part 52 and the first connection pad 21, and the bonding force is strong, and the stability of the electrical connection is improved. The concave design of the first concave surface 43 can also effectively prevent bridging of overflow tin. Moreover, the size of the metal frame 4 is easy to control, the size of the first conductive part 52 is roughly the same as the size of the first concave surface 43, and the size uniformity is good, which can improve the coplanarity of the first module structure 5. At the same time, through the support of the metal frame 4, the first module structure 5 is not easy to be offset.
[0083] See also Fig. 9As shown, the embodiment of the present application also provides a circuit board 200, which is different from the circuit board 100 provided in the above embodiment in that: a second module structure 9 is also provided on the side of the circuit substrate 10 away from the first module structure 5, at this time, the mounting hole 101 also penetrates the second connection pad 32, the metal frame 4 also includes a second connection end 46 located on the frame body 41 away from the first connection end 42, the second connection end 46 is electrically connected to the second connection pad 32 and extends out of the mounting hole 101, and the second connection end 46 has a second concave surface 47 that is concave toward one side of the frame body 41. The second module structure 9 includes a second element 91 and a plurality of second conductive portions 92 provided on the side of the second element 91 close to the circuit substrate 10, and the second conductive portions 92 are located in the corresponding second concave surfaces 47, so that the second module structure 9 is fixed and electrically connected to the circuit substrate 10 through the metal frame 4.
[0084] In some embodiments, a microstructure may also be provided on the second concave surface 47 . The specific form may refer to the microstructure 45 in the first concave surface 43 in the aforementioned embodiment, and will not be elaborated herein.
[0085] The embodiment of the present application improves the metal frame 4 so as to realize the design of a double-sided connection module structure for the circuit substrate 10 , thereby optimizing the layout of the circuit board 100 and improving the applicable scenarios of the circuit board 100 .
Claims
1. A circuit board, characterized in that: include: A circuit substrate, comprising a first circuit layer located on the outside, the first circuit layer comprising a plurality of first connection pads, the circuit substrate having a plurality of mounting holes corresponding to the first connection pads, each of the mounting holes penetrating the corresponding first connection pad; A plurality of metal frames, each of the metal frames is located in one of the mounting holes, the metal frames include a frame body and a first connection end provided at one end of the frame body, the frame body is located in the mounting hole, the first connection end is electrically connected to the first connection pad and extends out of the mounting hole, and the first connection end includes a first concave surface that is concave toward one side of the frame body; as well as The first module structure is located on a side of the circuit substrate where the first circuit layer is set. The first module structure includes a first element and a plurality of first conductive parts located on the first element close to the first circuit layer. Each of the first conductive parts is located in a corresponding first concave surface.
2. The circuit board according to claim 1, characterized in that The circuit substrate further includes a second circuit layer, the second circuit layer includes a plurality of second connection pads corresponding to the first connection pads, the second connection pads are exposed from the mounting holes, and the frame is electrically connected to the second connection pads.
3. The circuit board according to claim 2, characterized in that: A conductive adhesive layer is disposed between the frame and the second connection pad, the mounting hole partially extends into the second connection pad to form a groove on the second connection pad, and the conductive adhesive layer is located in the groove.
4. The circuit board according to claim 3, characterized in that: The conductive adhesive layer also extends between the frame and the hole wall of the mounting hole.
5. The circuit board according to claim 1, wherein: The first connection end includes a first end close to the frame and a second end away from the frame, and the outer diameter of the first connection end along the extension direction of the circuit substrate increases from the first end to the second end. The mounting hole comprises a first hole corresponding to the first connecting pad, the first connecting end is located in the first hole and extends out from the first hole, and the first hole has a concave structure matching with the outer surface of the first connecting end.
6. The circuit board according to claim 1, wherein: The frame has a hollow cavity, and a heat-conducting medium or a cooling medium is arranged in the cavity; or The frame is a hollow structure, and adhesive is arranged in the hollow structure. The adhesive passes through the frame and is connected to the hole wall of the installation hole.
7. The circuit board according to claim 1, characterized in that: The metal frame is made of gold, silver, copper or aluminum.
8. The circuit board according to claim 1, wherein: The first concave surface is provided with a plurality of microstructures, wherein the microstructures are protrusions, pits or grids.
9. The circuit board according to claim 1, characterized in that: The circuit substrate further includes a second circuit layer stacked with the first circuit layer, the second circuit layer includes a plurality of second connection pads corresponding to the first connection pads, the mounting hole also penetrates the corresponding second connection pads, the metal frame further includes a second connection end disposed on the frame body away from the first connection end, the second connection end is electrically connected to the second connection pad and extends out of the mounting hole, the second connection end includes a second concave surface that is concave toward the first connection end, The circuit board also includes a second module structure located on the side of the second circuit layer away from the first circuit layer, the second module structure includes a second element and a plurality of second conductive parts located on the second element close to the second circuit layer, each second conductive part is located in a corresponding second concave surface.
10. The circuit board according to claim 1, wherein: A heat dissipation layer is provided between the first module structure and the first circuit layer, and the material of the heat dissipation layer is insulating thermal conductive resin.