A package substrate and a leadless package device

Abstract

This invention relates to the field of semiconductor packaging technology, and discloses a packaging substrate and a leadless packaging device. The packaging substrate includes: a substrate body, a first pad group, and a first venting groove; the first pad group is disposed in a first target area on one side of the substrate body, and includes a plurality of first pads spaced apart; the first venting groove is formed at least in the first target area on one side of the substrate body, and is located between adjacent first pads. In this invention, the first pad group disposed on the substrate body matches the large-area thermally conductive pads in the packaged element, enabling the large-area thermally conductive pads in the packaged element to be soldered and fixed to the first pad group; the first venting groove is formed in the gap area between adjacent first pads, which not only does not affect the soldering area between the first pads and the packaged element to be mounted, but also ensures that the gas generated during the soldering process can be fully discharged, avoiding solder voids, improving soldering quality, and ultimately achieving the reliability of the packaged device.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging technology, and more specifically to a packaging substrate and a leadless packaging device. Background Technology

[0002] The Quad Flat No-leads Package (QFN) is a type of leadless surface-mount package. It is square or rectangular in shape, with a large exposed pad at the center of the bottom for heat dissipation. Electrically conductive pads surround the large pad around the perimeter of the package. QFN packages offer excellent electrical and thermal performance, and their small size and light weight have made them an ideal choice for many new applications, making them a hot topic in the industry.

[0003] QFN packages are mounted on organic substrates via SMT (Surface Mount Technology). SMT is a circuit assembly technology that mounts leadless or short-lead surface-mount components onto the surface of an organic substrate and assembles them using reflow soldering. However, during the soldering process between the large thermally conductive pads of QFN packages and the organic substrate, the flux inside the solder paste used in the printing process vaporizes and evaporates during heating. The resulting gas is difficult to completely escape from the center of the large solder area, easily leading to solder voids and affecting the reliability of QFN packaged devices. Summary of the Invention

[0004] In view of this, the present invention provides a packaging substrate and a leadless packaging device to solve the problem that the gas generated during the soldering process of semiconductor packaging devices is difficult to completely expel in a large area of ​​the soldering surface, which can easily lead to soldering voids and thus affect the reliability of semiconductor packaging devices.

[0005] In a first aspect, the present invention provides a packaging substrate, comprising: a substrate body, a first pad group, and a first venting groove; the first pad group is disposed in a first target area on one side of the substrate body, the first pad group comprising a plurality of first pads spaced apart; the first venting groove is formed at least in the first target area on one side of the substrate body and is located between adjacent first pads.

[0006] Beneficial effects: In this invention, the area where the first pad group is located on the substrate body is suitable for matching with the large-area thermally conductive pad in the packaged element, so that the large-area thermally conductive pad in the QFN packaged element can be welded and fixed to the first pad group; a first venting groove with a certain depth is formed in the gap area between adjacent first pads, which will not affect the welding area between the first pad and the packaged element to be mounted, and can ensure that the gas generated during the welding process can be fully discharged, avoiding the generation of welding voids, improving welding quality, and finally realizing the reliable fixation of leadless packaged elements with large-area thermally conductive pads, such as QFN packaged elements, on the packaged substrate.

[0007] In one alternative implementation, a plurality of first pads in the first pad group are arranged in a rectangular array.

[0008] Beneficial effects: Multiple first pads are arranged in a matrix, resulting in uniform and stable welding force and a simple structure, which helps to maximize the welding area within a limited region.

[0009] In one alternative implementation, the first exhaust channel extends in a grid pattern.

[0010] Beneficial effects: The matrix arrangement of multiple first pads has horizontal and vertical gap areas between them. The first venting grooves extending in a grid shape are set in these gap areas. The manufacturing process is simple and highly practical. Venting groove space is set between each adjacent first pad, which does not affect the effective welding area and can ensure the venting effect.

[0011] In one alternative embodiment, an isolation portion protruding from the surface of the substrate body is provided between adjacent first pads, and a first vent groove is formed in the isolation portion to isolate the first vent groove from the first pad.

[0012] Beneficial effects: An additional solder mask layer or a partially protruding insulating material is provided between adjacent first pads. The first venting groove is opened in the insulating material. On the horizontal plane, the first venting groove is relatively isolated from the window area of ​​the first pad. When each first pad is fixed to the large-area pad of the packaged component by solder paste, the flow of solder paste into the first venting groove can be reduced, ensuring the smooth flow of the first venting groove space and the venting effect.

[0013] In one alternative embodiment, there is a gap region between adjacent first pads, and a first venting groove is formed in the substrate body corresponding to the gap region. The first venting groove is connected to at least a portion of the first pads.

[0014] Beneficial effects: The substrate body may have a solder resist layer or a partially protruding insulating material on its upper surface, but these insulating materials do not completely isolate the first venting groove and the first pad opening, and there is a partially connected gap space between the first venting groove and the first pad opening area; or the substrate body surface may only have a pad structure without other protective layers such as insulating materials, and the first venting groove is opened on the substrate body between multiple mutually spaced first pads. The first venting groove extends into the substrate body. When the large-area pad of the packaged component to be mounted contacts and is fixed with the first pad of the first pad group, the first venting groove with downward extension space effectively enhances the venting space, thereby ensuring the venting effect; the first venting groove is connected to at least part of the first pad, which helps the welding gas generated at the first pad to enter the first venting groove smoothly, resulting in high venting efficiency, and the packaged substrate structure is simple and easy to manufacture.

[0015] In one optional embodiment, it further includes: a second pad group, disposed in a second target area on one side of the substrate body and spaced apart from the first pad group; the number of the second pad groups is the same as the number of sides of the substrate body; any second pad group includes a plurality of second pads spaced apart.

[0016] Beneficial effects: A second pad group is provided in the second target area of ​​the substrate body of the mounting module components for circuit connection with the components to be mounted, and the edge setting also facilitates electrical interconnection with the structure of other functional areas on the packaging substrate, which helps to improve the packaging integration.

[0017] In one optional embodiment, the substrate further includes: a third pad group and a fourth pad group, disposed on the side surface of the substrate body opposite to the first pad group; the third pad group includes a plurality of third pads spaced apart, and the third pad group is corresponding to the first pad group; the fourth pad group includes a plurality of fourth pads spaced apart, and the fourth pad group is corresponding to the second pad group.

[0018] Beneficial effects: The first and second pad groups are located on one side of the top surface of the substrate body, while the third and fourth pad groups are located on one side of the bottom surface of the substrate body. The pads on the top surface and the pads on the bottom surface have the same structure and correspond vertically, which facilitates efficient process execution, simplifies processing equipment, and facilitates the mounting of the package substrate to other components for electrical interconnection.

[0019] In one alternative embodiment, the substrate body includes:

[0020] Core layer;

[0021] A first substrate layer is disposed on one side surface of the core layer, and a first pad group and a second pad group are disposed on the side of the first substrate layer away from the core layer.

[0022] The second substrate layer is disposed on the surface of the core layer opposite to the first substrate layer; the third pad group and the fourth pad group are disposed on the side of the second substrate layer opposite to the core layer.

[0023] The via structure penetrates the core layer, the first substrate layer, and the second substrate layer, and its two ends are connected to the first pad group and the third pad group, respectively. The inner wall of the via structure is formed with conductive metal, one end of which is connected to the first pad and the other end is connected to the third pad.

[0024] Beneficial effects: A first substrate layer and a second substrate layer are formed on both sides of the core layer for insulation protection. A first pad group and a second pad group are provided on the first substrate layer. A third pad group and a fourth pad group are provided on the second substrate layer. A via structure with conductive metal is provided to penetrate the core layer, the first substrate layer and the second substrate layer, and to connect the first pad group and the third pad group from top to bottom, so as to realize the electrical connection between the two sides of the packaging substrate.

[0025] In one alternative implementation, it further includes:

[0026] A first solder mask layer is disposed on the side surface of the first substrate layer away from the core layer; the first solder mask layer has a first opening and a second opening, the first opening corresponding to expose the first pad group, and the second opening corresponding to expose the second pad group; the first solder mask layer isolates adjacent first pads, and a first vent groove penetrates the first solder mask layer between adjacent first pads.

[0027] The second solder mask layer is disposed on the side surface of the second substrate layer away from the core layer; the second solder mask layer has a third opening and a fourth opening, the third opening corresponding to expose the third pad group, and the fourth opening corresponding to expose the fourth pad group; the second solder mask layer isolates adjacent third pads, and the second vent groove penetrates the second solder mask layer between adjacent third pads, and the second vent groove is disposed corresponding to the first vent groove.

[0028] Beneficial effects: A first solder resist layer is also covered on one side of the first substrate layer, and a second solder resist layer is covered on one side of the second substrate layer. The first and second solder resist layers are insulating ink protective layers that isolate the soldered and non-soldered parts on the top and bottom sides of the packaging substrate, while also providing anti-oxidation protection for the pad structure. Furthermore, the first vent hole is located in the first solder resist layer, and the second vent hole is located in the second solder resist layer, avoiding any impact on the substrate body and the soldering surface, and ensuring the performance of the packaged device.

[0029] In a second aspect, the present invention also provides a leadless package device, comprising: the aforementioned package substrate, a leadless package element, and a solder flux layer, wherein the leadless package element is disposed on the package substrate; the leadless package element includes a thermally conductive pad and an insulating layer covering the thermally conductive pad, at least one end of the thermally conductive pad protruding from the insulating layer, and the thermally conductive pad is connected to a first pad group; the solder flux layer is disposed between the first pad group and the thermally conductive pad, and the solder flux layer protrudes from the surface of the substrate body.

[0030] Beneficial effects: The leadless package element of the present invention can be a QFN package element. The leadless package element includes a central thermally conductive pad, an edge conductive pad, and an insulating layer covering the outside. The insulating layer provides insulation protection for the thermally conductive pad, the conductive pad, and the chip, etc. The thermally conductive pad and the conductive pad have exposed soldering surfaces that connect to the outside. During soldering, a flux layer is disposed between the leadless package element and the package substrate to achieve soldering and fixing of the thermally conductive pad and the first pad group. At the same time, due to the presence of the flux layer, a gap is formed between the leadless package element and the package substrate, which facilitates the exhaust of gas in the first venting groove to the external space and reduces solder voids. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a top view schematic diagram of a packaging substrate in related technologies;

[0033] Figure 2 This is a top view schematic diagram of another type of packaging substrate in related technologies;

[0034] Figure 3 This is a top view of the packaging substrate according to an embodiment of the present invention;

[0035] Figure 4 This is a top view schematic diagram of an organic substrate having an encapsulation substrate according to an embodiment of the present invention;

[0036] Figure 5 It is based on Figure 3 A first cross-sectional view of the packaging substrate cut by AA, showing that the first vent groove and the first pad are isolated from each other;

[0037] Figure 6 This is a second cross-sectional view of the packaging substrate of this invention, which has a first vent groove and a first pad isolated from each other.

[0038] Figure 7 This is a first cross-sectional view of the packaging substrate of the present invention, which has a first vent groove and a first pad connected in communication.

[0039] Figure 8 This is a second cross-sectional view of the packaging substrate of this invention, which has a first vent groove and a first pad connected in communication.

[0040] Figure 9 This is a schematic diagram of the structure of a leadless packaged component according to an embodiment of the present invention.

[0041] Explanation of reference numerals in the attached figures:

[0042] B. Organic substrate; a. Central large pad; b. Central pad assembly;

[0043] 100. Packaging substrate; 200. Leadless package component; 201. Thermally conductive pad; 202. Insulating layer; 203. Conductive pad;

[0044] 1. Substrate body; 11. Core layer; 12. First substrate layer; 13. Second substrate layer; 14. Via structure; 15. Conductive metal;

[0045] 2. First pad group; 21. First pad;

[0046] 3. First exhaust groove;

[0047] 4. Second pad group; 41. Second pad;

[0048] 5. Third pad group; 51. Third pad;

[0049] 6. Second exhaust channel;

[0050] 71. Fourth pad;

[0051] 8. First solder mask layer; 81. First opening; 82. Second opening;

[0052] 9. Second solder mask layer; 91. Third opening; 92. Fourth opening. Detailed Implementation

[0053] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the drawings, not all structures. In the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concept of the invention. Various structural schematic diagrams according to embodiments of the present invention are shown in the drawings. These figures are not drawn to scale, and some details are enlarged for clarity, and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from actual practices due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed. In the context of the present invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. Additionally, if one layer / component is "above" another layer / component in one orientation, then when the orientation is reversed, that layer / component can be "below" that other layer / component.

[0054] In related technologies, the packaging substrate used for soldering and fixing a square flat no-lead (QFN) package has a large 3×3mm copper foil with a fully open window. The open window area forms a large, heat-conducting central pad a, such as... Figure 1 As shown. When placing QFN packaged components on an organic substrate using surface mount technology (SMT), the leadless packaged components are first mounted on the substrate surface, and then assembled using methods such as reflow soldering. However, during the soldering assembly process, the gas generated in the large soldering surface is difficult to completely escape, easily forming bubbles and causing voids, thus affecting product reliability. Furthermore, a matrix-style central pad group b, after dividing the large central pad a, is shown... Figure 2 As shown, this method also cannot efficiently solve the problem of weld voids.

[0055] Based on this, refer to Figures 3 to 9 This embodiment provides a packaging substrate 100, including: a substrate body 1, a first pad group 2 and a first venting groove 3; the first pad group 2 is disposed in a first target area on one side of the substrate body 1, and the first pad group 2 includes a plurality of first pads 21 disposed at intervals; the first venting groove 3 is formed at least in the first target area on one side of the substrate body 1 and is located between adjacent first pads 21.

[0056] See Figure 4The aforementioned packaging substrate 100 can be a functional area in a carrier such as an organic substrate B that enables high-precision and high-sealing electrical interconnection of electronic components. In this embodiment, the packaging substrate 100 only refers to the area on the organic substrate B where one component of the module is mounted. Other areas on the organic substrate B include circuit interconnection areas, other component mounting areas, etc. Specifically, a first pad group 2 is provided in a first target area on one side surface of the substrate body 1. The first pad group 2 includes a plurality of first pads 21 spaced apart. The first pads 21 are made of a metal material with excellent conductivity, such as copper. The size and shape of the plurality of first pads 21 are not limited. For example, the first target area can be the middle area of ​​the substrate body 1. The middle area here is not strictly limited to the area equidistant from the two opposite sides of the substrate body. There can also be a partial offset, as long as the area where the first pad group 2 is located matches the large-area thermally conductive pad 201 in the packaged element. This allows the large-area thermally conductive pad 201 in the QFN packaged element to be welded and fixed to the first pad group 2. In this embodiment, a first venting groove 3 with a certain depth is formed between adjacent first pads 21. This will not affect the welding area between the first pad 21 and the packaged element to be mounted, and can ensure that the gas generated during the welding process can be fully discharged, avoiding welding voids, improving welding quality, and finally achieving reliable fixation of the leadless packaged element 200 with a large-area thermally conductive pad 201, such as QFN, on the packaged substrate 100.

[0057] In one embodiment, see Figure 3 The first pads 21 in the first pad group 2 are arranged in a rectangular array.

[0058] In this embodiment, the first pad 21 is a square pad. This type of pad has a regular shape and is easy to process and solder. Multiple square first pads 21 are arranged in a matrix, so the overall welding force is uniform and stable, and the structure is simple, which helps to maximize the welding area in a limited area.

[0059] Of course, the first pad 21 can also be a circular pad, an island pad, a teardrop pad, a polygonal pad, an elliptical pad, or other special-shaped pads. Among them, circular pads can evenly distribute the thermal stress during welding, reduce the generation of welding cracks, and improve the reliability of welding; elliptical pads have sufficient area to enhance peel resistance, so circular pads and elliptical pads can also be preferred pad types.

[0060] Based on the above scheme, the first exhaust trough 3 is extended in a grid shape.

[0061] Correspondingly, there are horizontal and vertical gap areas between the multiple first pads 21 arranged in a matrix. The first exhaust grooves 3 extending in a grid shape are set in the gap areas. The manufacturing process is simple and the practicality is strong. Each adjacent first pad 21 is provided with an exhaust groove space, which does not affect the effective welding area and can ensure the exhaust effect.

[0062] In addition, in this embodiment, the first venting groove 3 is set to extend only to the edge of the first pad group 2, that is, the end of the first venting groove 3 is aligned with the end of the first pad group 2. This ensures the venting effect while improving the surface aesthetics of the packaging substrate 100. At the same time, it prevents external impurities from entering the first venting groove 3 and affecting the performance of the packaging components and the packaging substrate 100, thus ensuring the reliability of the packaging device.

[0063] In one alternative embodiment, an isolation portion protruding from the surface of the substrate body 1 is provided between adjacent first pads 21, and a first venting groove 3 is formed in the isolation portion to isolate the first venting groove 3 from the first pads 21.

[0064] An isolation portion protruding from the surface of the substrate body 1 between adjacent first pads 21, the isolation portion may be as follows: Figure 5 The additional insulating material shown, such as the first solder resist layer, can also be as follows: Figure 6 The structure formed by the upward protrusion of the substrate body 1 shown in the figure has a first venting groove 3 formed in the isolation part. On the horizontal plane, the first venting groove 3 is relatively isolated from the window area of ​​the first pad 21. The width of the first venting groove 3 is not specifically limited and can be set according to the gap size between the specific first pads 21, which is highly flexible. Under this structure, when each first pad 21 is fixed to the large-area pad of the packaged component by solder paste, the flow of solder paste into the first venting groove 3 can be reduced, ensuring the smooth flow of the space of the first venting groove 3 and the venting effect.

[0065] In another alternative embodiment, there is a gap region between adjacent first pads 21, and the substrate body 1 corresponding to the gap region has a first venting groove 3, which is connected to at least a portion of the first pads 21.

[0066] That is, an isolation portion protruding from the surface of the substrate body 1 can be provided between adjacent first pads 21. The isolation portion can be an additional insulating material such as the first solder resist layer, or it can be a structure formed by a portion of the substrate body 1 protruding upwards. However, the isolation portion does not completely isolate all the first venting grooves 3 and the openings of the first pads 21. There is a partially connected space between the opening areas of the first venting grooves 3 and the first pads 21. That is, the first pads 21 and the first venting grooves 3 can be partially connected on the side, and the other part can be blocked by the isolation portion. Figure 7As shown; or, on one side of the substrate body 1, only a pad structure is provided on the horizontal surface, without other structural layers, and a first venting groove 3 is formed on the substrate body 1 between multiple spaced first pads 21. The first venting groove 3 extends into the substrate body 1. When the large-area pads of the packaged components contact and are fixed to the first pads 21 of the first pad group 2, the first venting groove 3, which has a downward extending space, effectively enhances the venting space, thereby ensuring the venting effect, such as Figure 8 As shown, the first exhaust groove 3 is connected to at least part of the first pad 21, which helps the welding gas generated at the first pad 21 to smoothly enter the first exhaust groove 3, resulting in high exhaust efficiency. Furthermore, the packaging substrate 100 has a simple structure and is relatively easy to manufacture.

[0067] like Figure 3 As shown, the packaging substrate 100 of this embodiment also includes a second pad group 4. The second pad group 4 is disposed in a second target area on one side of the substrate body 1 and is spaced apart from the first pad group 2. The number of the second pad groups 4 is the same as the number of sides of the substrate body 1. Each second pad group 4 includes a plurality of second pads 41 spaced apart.

[0068] A second set of pads 4 is provided in the second target area of ​​the substrate body 1 of the mounting module components for circuit connection with the components to be mounted. In this embodiment, the second target area is the edge area of ​​the substrate body 1. The edge setting facilitates electrical interconnection with the structure of other functional areas on the packaging substrate 100, which helps to improve the packaging integration. In this embodiment, the surface of the substrate body 1 is quadrilateral, so the second set of pads 4 is set to four groups, and each second set of pads 4 includes a plurality of first pads 21 arranged sequentially and spaced along the edge of the substrate body 1, which facilitates reliable electrical interconnection from all directions.

[0069] The packaging substrate 100 in this embodiment can be configured to have a single-sided pad or a double-sided pad.

[0070] In one embodiment, when the packaging substrate 100 has a double-sided pad structure, the packaging substrate 100 further includes: a third pad group 5 and a fourth pad group disposed on the side surface of the substrate body 1 opposite to the first pad group 2. The third pad group 5 includes a plurality of third pads 51 disposed at intervals, and the third pad group 5 is disposed corresponding to the first pad group 2. The fourth pad group includes a plurality of fourth pads 71 ​​disposed at intervals, and the fourth pad group is disposed corresponding to the second pad group 4.

[0071] See Figures 5 to 8The first pad group 2 and the second pad group 4 are disposed on one side of the top surface of the substrate body 1, and the third pad group 5 and the fourth pad group are disposed on one side of the bottom surface of the substrate body 1. In this embodiment, the pads on the top surface and the pads on the bottom surface have the same structure and correspond vertically, which facilitates efficient process execution, simplifies processing equipment, and facilitates the mounting of the package substrate 100 to other components for electrical interconnection. Specifically, the first pad group 2 and the third pad group 5 correspond vertically and have the same shape and size, that is, the projections of the first pad 21 and the third pad 51 on the substrate body 1 coincide; the second pad group 4 and the fourth pad group correspond vertically and have the same shape and size, that is, the projections of the second pad 41 and the fourth pad 71 on the substrate body 1 coincide.

[0072] In one embodiment, such as Figures 5 to 8 As shown, the substrate body 1 includes: a core layer 11, a first substrate layer 12, a second substrate layer 13, and a via structure 14; the first substrate layer 12 is disposed on one side surface of the core layer 11, and the first pad group 2 and the second pad group 4 are disposed on the side of the first substrate layer 12 away from the core layer 11; the second substrate layer 13 is disposed on the other side surface of the core layer 11 away from the first substrate layer 12, and the third pad group 5 and the fourth pad group are disposed on the side of the second substrate layer 13 away from the core layer 11; the via structure 14 is disposed through the core layer 11, the first substrate layer 12, and the second substrate layer 13, and its two ends are respectively connected to the first pad group 2 and the third pad group 5; a conductive metal 15 is formed on the inner wall surface of the via structure 14, one end of the conductive metal 15 is connected to the first pad 21, and the other end is connected to the third pad 51.

[0073] Specifically, the core layer 11 is mainly composed of copper foil, solid resin material, and glass fiber. The solid resin material sandwiches and covers the glass fiber, and copper foil is set on the upper and lower surfaces of the solid resin material. The core layer 11 has a certain hardness and thickness, serving as a basic component of the encapsulation substrate 100. The first substrate layer 12 and the second substrate layer 13 are both semi-solid sheets, composed of semi-solid resin material and glass fiber. The semi-solid resin material sandwiches and covers the glass fiber, and the two are combined to fill and bond. The first substrate layer 12 and the second substrate layer 13 are formed on both sides of the core layer 11 for insulation protection. The first substrate layer 12 is provided with a first pad group 2 and a second pad group 4, and the second substrate layer 13 is provided with a third pad group 5 and a fourth pad group. A via structure 14 with conductive metal 15 penetrates the core layer 11, the first substrate layer 12, and the second substrate layer 13, connecting the first pad group 2 and the third pad group 5 vertically. Of course, a vertically penetrating via structure 14 can also be provided between the second pad group 4 and the fourth pad group to achieve electrical connection. In this embodiment, the conductive metal 15 and the third pad 51 are made of the same metal material as the first pad 21. During the preparation process, vertical through holes can be formed first at specific positions of the core layer 11, the first substrate layer 12 and the second substrate layer 13. Then, the conductive metal 15 is formed on the inner wall of the through hole. After that, the first pad 21 and the second pad 41 are formed on the surfaces of the first substrate layer 12 and the second substrate layer 13, respectively, and are integrally formed with the conductive metal 15. Of course, other conductive materials or insulating materials can also be filled into the through hole, as long as the electrical connection between the upper and lower pads can be achieved.

[0074] Furthermore, such as Figure 5 As shown, the packaging substrate 100 of this embodiment further includes a first solder resist layer 8 and a second solder resist layer 9. The first solder resist layer 8 is disposed on the side surface of the first substrate layer 12 away from the core layer 11. The first solder resist layer 8 has a first opening 81 and a second opening 82. The first opening 81 exposes the first pad group 2, and the second opening 82 exposes the second pad group 4. The first venting groove 3 penetrates a portion of the first solder resist layer 8 between adjacent first pads 21. The second solder resist layer 9 is disposed on the side surface of the second substrate layer 13 away from the core layer 11. The second solder resist layer 9 has a third opening 91 and a fourth opening 92. The third opening 91 exposes the third pad group 5, and the fourth opening 92 exposes the fourth pad group. The second venting groove 6 penetrates a portion of the second solder resist layer 9 between adjacent third pads 51, and the second venting groove 6 is correspondingly disposed with the first venting groove 3.

[0075] Specifically, a first solder resist layer 8 is also covered on one side of the first substrate layer 12, and a second solder resist layer 9 is covered on one side of the second substrate layer 13. The first solder resist layer 8 and the second solder resist layer 9 are insulating ink protective layers that separate the soldered and non-soldered portions on the top and bottom sides of the packaging substrate 100, while also providing anti-oxidation protection for the pad structure. Green solder resist is used in this embodiment. On the top side of the substrate body 1, the first solder resist layer 8 has multiple first openings 81 to expose multiple first pads 21 of the first pad group 2, forming first pad 21 windows. In addition, the first venting groove 3 penetrates the first solder resist layer 8 between adjacent first pads 21. In other embodiments, it may also extend appropriately into the first substrate layer 12. The first solder resist layer 8 also has multiple second openings 82 to expose multiple second pads 41 of the second pad group 4, forming second pad 41 windows. Similarly, on one side of the bottom surface of the substrate body 1, the second solder mask layer 9 has a plurality of third openings 91 to expose a plurality of third pads 51 of the third pad group 5, forming a window for the third pad 51; the second solder mask layer 9 also has a plurality of fourth openings 92 to expose a plurality of fourth pads 71 ​​of the fourth pad group, forming a window for the fourth pad 71; correspondingly, the second venting groove 6 penetrates the second solder mask layer 9 between adjacent third pads 51, and in other embodiments, it may also extend into the second substrate layer 13 as appropriate.

[0076] refer to Figures 3 to 9 This embodiment also provides a leadless package device, including: the above-mentioned package substrate 100, the leadless package element 200, and a solder flux layer. The leadless package element 200 is disposed on the package substrate 100. The leadless package element 200 includes a thermally conductive pad 201 and an insulating layer 202 covering the thermally conductive pad 201. At least one end of the thermally conductive pad 201 is exposed from the insulating layer 202. The thermally conductive pad 201 is connected to a first pad group 2. The solder flux layer is disposed between the first pad group 2 and the thermally conductive pad 201, and the solder flux layer protrudes from the surface of the substrate body 1.

[0077] In this embodiment, the leadless package element 200 can be a QFN package element, such as... Figure 9As shown, the leadless package element 200 includes a central thermally conductive pad 201, an edge conductive pad 203, and an insulating layer 202 covering the outside. The insulating layer 202 provides insulation protection for the thermally conductive pad 201, the conductive pad 203, and other components such as chips. The thermally conductive pad 201 and the conductive pad 203 have exposed soldering surfaces that connect to the outside. The flux layer is solder paste. During soldering, the flux layer is placed between the leadless package element 200 and the package substrate 100 to achieve soldering and fixing of the thermally conductive pad 201 and the first pad group 2. At the same time, due to the presence of the flux layer, a gap is formed between the leadless package element 200 and the package substrate 100, which facilitates the discharge of gas in the first venting groove 3 to the external space, reducing solder voids.

[0078] The process of fixing the leadless packaged device onto the packaged substrate 100 includes: firstly, setting a flux layer on the first pad 21 and the second pad 41 on one side of the top surface of the packaged substrate 100; then, using a tool such as tweezers, holding the leadless packaged element 200 so that the side with the thermally conductive pad 201 faces the packaged substrate 100, and applying flux material to the surface of the side of the leadless packaged element 200 with the thermally conductive pad 201; then, placing the leadless packaged element 200 onto the packaged substrate 100, roughly aligning it with the area where the first pad group 2 is located; then, using a hot air gun welding tool, after adjusting the hot air gun temperature and speed appropriately, first tilting the hot air gun outlet towards the side of the leadless packaged element 200, and then vertically aligning it towards the upper surface of the leadless packaged element 200 to complete the melting of the flux layer, and fixing the leadless packaged element 200 onto the packaged substrate 100 under the action of liquid tension.

[0079] Further functional descriptions of the above structures are the same as those of the corresponding embodiments described above, and will not be repeated here.

[0080] The above description does not provide detailed explanations of the technical aspects of each layer's patterning, etching, etc. However, those skilled in the art should understand that various technical means can be used to form layers and regions of the desired shape. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above. Additionally, although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination.

[0081] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A packaging substrate, characterized in that, include: substrate body; A first pad group is disposed in a first target area on one side of the substrate body; the first pad group includes a plurality of first pads arranged at intervals. The first venting groove is formed at least on a first target area on one side surface of the substrate body and is located between adjacent first pads; the first venting groove extends in a grid shape. A third pad group is disposed on the surface of the substrate body opposite to the first pad group; the third pad group includes a plurality of third pads arranged at intervals, and the third pad group is disposed corresponding to the first pad group; A first solder resist layer is disposed on one side surface of the substrate body; the first solder resist layer has a first opening, the first opening corresponding to expose the first pad group; the first solder resist layer isolates adjacent first pads, and the first vent groove penetrates the first solder resist layer between adjacent first pads. A second solder mask layer is disposed on the other side surface of the substrate body; the second solder mask layer has a third opening, the third opening corresponding to expose the third pad group; the second solder mask layer isolates adjacent third pads, and a second venting groove penetrates the second solder mask layer between adjacent third pads, and the second venting groove is disposed corresponding to the first venting groove but is not connected.

2. The packaging substrate according to claim 1, characterized in that, The first pads in the first pad group are arranged in a rectangular array.

3. The packaging substrate according to claim 2, characterized in that, An isolation portion protruding from the surface of the substrate body is provided between adjacent first pads, and the first vent groove is formed in the isolation portion to isolate the first vent groove from the first pad.

4. The packaging substrate according to claim 2, characterized in that, There is a gap region between adjacent first pads, and the substrate body corresponding to the gap region has the first venting groove, which is connected to at least a portion of the first pad.

5. The packaging substrate according to any one of claims 1-4, characterized in that, Also includes: The second pad group is disposed in a second target area on one side of the substrate body and is spaced apart from the first pad group; the number of the second pad groups is the same as the number of sides of the substrate body; each second pad group includes a plurality of second pads spaced apart.

6. The packaging substrate according to claim 5, characterized in that, Also includes: A fourth pad group is disposed on the surface of the substrate body opposite to the first pad group; the fourth pad group includes a plurality of fourth pads arranged at intervals, and the fourth pad group is disposed corresponding to the second pad group.

7. The packaging substrate according to claim 6, characterized in that, The substrate body includes: Core layer; A first substrate layer is disposed on one side surface of the core layer, and the first pad group and the second pad group are disposed on the side of the first substrate layer opposite to the core layer. The second substrate layer is disposed on the surface of the core layer opposite to the first substrate layer; the third pad group and the fourth pad group are disposed on the side of the second substrate layer opposite to the core layer; A via structure is provided that penetrates the core layer, the first substrate layer and the second substrate layer, and its two ends are respectively connected to the first pad group and the third pad group; the inner wall surface of the via structure is formed with conductive metal, one end of which is connected to the first pad and the other end of which is connected to the third pad.

8. The packaging substrate according to claim 7, characterized in that, The first solder mask layer is disposed on the side surface of the first substrate layer opposite to the core layer; the first solder mask layer also has a second opening, the second opening corresponding to expose the second pad group; The second solder resist layer is disposed on the side surface of the second substrate layer opposite to the core layer; The second solder mask layer also has a fourth opening, which exposes the fourth pad group.

9. A leadless packaged device, characterized in that, include: The packaging substrate according to any one of claims 1-8; A leadless packaged component is disposed on the package substrate; The leadless package includes a thermal pad and an insulating layer covering the thermal pad, at least one end of the thermal pad protruding from the insulating layer, and the thermal pad is connected to the first pad group. A flux layer is disposed between the first pad group and the thermally conductive pad, and the flux layer protrudes from the surface of the substrate body.

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