Surface-mounted heat dissipation bonding pad, semiconductor packaging piece and surface mounting method

Abstract

The invention discloses a surface-mounted heat dissipation bonding pad, a semiconductor packaging piece and a surface mounting method, and relates to the technical field of electronics, the surface-mounted heat dissipation bonding pad comprises a bonding pad body and a solder mask layer, the bonding pad body is provided with a welding surface and a heat dissipation surface which are oppositely arranged, and the solder mask layer is arranged on the bonding pad body. A plurality of first heat dissipation through holes penetrating through the welding surface and the heat dissipation surface are formed in the bonding pad body in an array mode, and the solder mask layer is located on the welding surface of the bonding pad body and is arranged around the edge area of the welding surface, so that in the packaging process of the surface-mounted device, the surface-mounted device can be packaged in a one-time tin brushing mode on the welding surface; according to the invention, the tin material which is enough to fill the heat dissipation via hole and the welding surface is arranged on the bonding pad body, so that the subsequent heating and welding times are reduced, the related process steps in the packaging process are saved, the production cost of the product is reduced, the product supporting efficiency is improved, and the production period is shortened.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and in particular to a surface mounted heat dissipation pad, a semiconductor package and a surface mounting method. Background Art

[0002] With the popularization of surface mount devices, the heat dissipation problem of high-power surface mount devices directly affects the reliability of electronic equipment. Generally speaking, PCB boards (Printed Circuit Boards) will use processes such as copper embedding and electroplated copper hole filling to meet the heat dissipation requirements of surface mount devices.

[0003] In addition, there is also a method of filling tin with heat dissipation pads to achieve the purpose of providing heat dissipation for surface mount devices. One of the implementation methods is to brush tin on the heat dissipation pads, so that the tin fills the heat dissipation vias after heating and liquefaction, and then brush tin on the heat dissipation pads for a second time to complete the soldering of surface mount devices. The second implementation method is to use reflow soldering combined with wave soldering, first fill the heat dissipation vias with tin from the bottom of the PCB through wave soldering, then brush tin on the heat dissipation pads and solder the surface mount devices through reflow soldering.

[0004] However, the above traditional methods all require two tinning and two heating to complete the filling of tin material and the welding of components, resulting in problems such as generally high production costs, low process efficiency and long production cycle. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a surface mount heat dissipation pad, a semiconductor package and a surface mounting method, which can solve the above-mentioned problems existing in the prior art.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, a surface mount heat dissipation pad is provided, comprising:

[0008] A pad body, wherein the pad body is formed with a welding surface and a heat dissipation surface disposed opposite to each other, and a plurality of first heat dissipation vias penetrating the welding surface and the heat dissipation surface are arranged in an array on the pad body;

[0009] A solder resist layer is located on the soldering surface of the pad body and is arranged around an edge area of ​​the soldering surface.

[0010] As an optional implementation, the diameter of the first heat dissipation via is set to 0.2 mm-0.3 mm;

[0011] A heat dissipation copper layer is also arranged around the first heat dissipation via hole, and the thickness of the heat dissipation copper layer is 0.025 mm.

[0012] As an optional implementation manner, the distance between the hole wall of the first heat dissipation via and the edge of the pad body is set to be ≥0.3 mm;

[0013] The hole wall spacing between any two adjacent first heat dissipation vias is set to be ≥0.3 mm.

[0014] As an optional implementation, the thickness of the solder resist layer protruding from the soldering surface is set to 0.01 mm-0.04 mm.

[0015] As an optional implementation, the width of the solder resist layer is set to 0.1 mm.

[0016] In a second aspect, a semiconductor package is provided, comprising:

[0017] The surface mount heat dissipation pad as described in the first aspect;

[0018] A substrate, wherein the pad body is embedded on one side of the substrate, the heat dissipation surface of the pad body faces the substrate, and the welding surface is flush with a surface of one side of the substrate, and the substrate is further provided with a plurality of second heat dissipation vias arranged in an array and corresponding to the first heat dissipation holes, and the second heat dissipation vias penetrate two opposite side surfaces of the substrate; and

[0019] A surface mount device is provided with a heat dissipation pin, and a side of the surface mount device provided with the heat dissipation pin is mounted on the substrate through the solder resist layer, so that the surface mount device, the solder resist layer and the welding surface enclose a cavity structure, the cavity structure is connected with the first heat dissipation via and the second heat dissipation via, and the cavity structure and the first heat dissipation via and the second heat dissipation via are all filled with solder.

[0020] As an optional implementation, it also includes:

[0021] The bottom heat dissipation pad is embedded in the side of the substrate away from the pad body, and the bottom heat dissipation pad is also provided with a plurality of third heat dissipation vias arranged in an array and corresponding to the second heat dissipation holes.

[0022] As an optional implementation, the substrate includes:

[0023] A substrate layer, wherein at least two substrate layers are provided, and the pad body is embedded in one of the substrate layers; and

[0024] The inner pad is arranged between any two adjacent substrate layers, and the second heat dissipation via penetrates each substrate layer and the inner pad.

[0025] As an optional implementation, it also includes:

[0026] A surface mount pad, wherein the surface mount pad is provided in plurality, and the plurality of surface mount pads are arranged at intervals on a side of the substrate provided with the pad body and surround the periphery of the welding surface;

[0027] The surface mount device is also provided with a plurality of functional pins, and each of the functional pins is connected to each of the surface mount pads via solder.

[0028] In a third aspect, a surface mounting method is provided, which is applied to the semiconductor package according to the second aspect, and the surface mounting method comprises the steps of:

[0029] S10, placing solder paste in a receiving groove formed by the welding surface and the solder resist layer;

[0030] S20, placing the surface mount device on a substrate and positioning the heat dissipation pins to correspond to the receiving grooves;

[0031] S30, heating the solder paste and liquefying the solder paste, so that the liquid tin gradually fills the receiving groove and flows to the second heat dissipation vias through the first heat dissipation vias under the action of gravity, so that the liquid level of the liquid tin in the receiving groove gradually decreases to be flush with the solder resist layer, and at the same time as the liquid tin fills the first heat dissipation vias and the second heat dissipation vias, the surface mount device is mounted on the solder resist layer;

[0032] S40, cooling and solidifying the liquid tin.

[0033] The beneficial effects of the present invention are as follows: the surface mount heat dissipation pad is provided with a solder resist layer surrounding the edge area of ​​the welding surface on the welding surface of the pad body, so as to avoid the situation that liquid tin overflows during the subsequent tin brushing and heating of the tin material. In this way, the tin material sufficient to fill the heat dissipation vias and the welding surface can be arranged on the pad body by only one tin brushing on the welding surface, thereby reducing the number of subsequent heating and welding times, saving relevant process steps in the packaging process, reducing the product production cost, and improving the product support efficiency and shortening the production cycle;

[0034] Since the solder mask is protruding from the soldering surface of the pad body, in the process of the tin material liquefying and flowing into the heat dissipation vias, as the liquid tin level on the soldering surface drops, the surface mount device can also be mounted on the solder mask, thereby forming a vacuum area between the surface mount device and the soldering surface. In this way, under the action of atmospheric pressure, it is ensured that the tin material will not flow out of the heat dissipation vias, ensuring that the filling effect of the tin material can meet the heat dissipation requirements of the device, that is, on the basis of meeting the packaging requirements of the device, the process steps can be simplified to achieve the purpose of reducing costs and increasing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention is further described in detail below based on the accompanying drawings and embodiments.

[0036] Figure 1 This is a schematic diagram of the structure of the surface mount heat dissipation pad according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the structure of a semiconductor package according to an embodiment of the present invention;

[0038] Figure 3 This is a flow chart of the surface mounting method described in an embodiment of the present invention.

[0039] In the figure: 10, pad body; 11, welding surface; 12, heat dissipation surface; 13, first heat dissipation via; 20, solder mask layer; 30, substrate; 31, second heat dissipation via; 32, substrate layer; 33, inner pad; 40, surface mount device; 41, heat dissipation pin; 42, functional pin; 50, bottom heat dissipation pad; 51, third heat dissipation via; 60, surface mount pad; 70, heat dissipation copper layer. DETAILED DESCRIPTION

[0040] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention are further described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0041] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0043] Surface Mounted Devices (SMD) are electronic components packaged using surface mount technology. Compared with traditional plug-in components, SMD has the advantages of small size, light weight, high installation density, and good reliability. Therefore, it is also widely used in various electronic devices, such as mobile phones, computers, televisions, communication equipment, etc.

[0044] There are many types of SMD, including resistors, capacitors, inductors, diodes, transistors, integrated circuits, etc. The pins or solder ends of these devices are usually designed to be flat, rectangular or other shapes to match and connect with the surface mount pads on the PCB. With the popularization of surface mount devices, the heat dissipation problem of high-power surface mount devices directly affects the reliability of electronic equipment. Generally speaking, PCB (Printed Circuit Board) will use copper embedding, copper electroplating and hole filling to meet the heat dissipation requirements of surface mount devices.

[0045] From the background technology, it can be known that in addition to using the above-mentioned process to solve the heat dissipation problem of surface-mounted devices, there is also a method of filling tin material with heat dissipation pads in the prior art to achieve the purpose of providing heat dissipation for surface-mounted devices. One of the implementation methods is to brush tin on the heat dissipation pad once, so that the tin material meets the requirements of filling the heat dissipation vias after heating and liquefaction, and then brush tin on the heat dissipation pad for a second time and complete the welding of the surface-mounted device. The second implementation method is to use the method of reflow soldering combined with wave soldering, first fill the heat dissipation vias with tin material from the bottom of the PCB through wave soldering, then brush tin on the heat dissipation pad and solder the surface-mounted device through reflow soldering.

[0046] However, the above traditional methods all require two tinning and two heating to complete the filling of tin material and the welding of components, resulting in problems such as generally high production costs, low process efficiency and long production cycle.

[0047] In view of this, the present embodiment provides a surface mount heat dissipation pad, which improves the structure of the solder mask layer on the heat dissipation pad to solve a series of technical problems such as the difficulty and complexity of the surface mount surface assembly process.

[0048] Please refer to the instruction manual Figure 1-Figure 2 The surface mount heat dissipation pad includes a pad body 10. The pad body 10 is used to connect the surface mount device 40 and the PCB board during the process of surface mount technology (SMT) and the like, so as to effectively conduct the heat generated by the surface mount device 40 to the surrounding environment, thereby maintaining the normal operating temperature of the surface mount device 40 and improving its service life and stability.

[0049] In order to facilitate a more comprehensive understanding of this implementation, the two opposite surfaces of the pad body 10 are defined as a welding surface 11 and a heat dissipation surface 12 in this embodiment. The welding surface 11 is the side of the pad body 10 facing the external environment of the PCB board, which is used for welding with the surface mount device 40 to achieve the heat transfer function. Its design is to maximize the heat dissipation path between the surface mount device 40 and the pad body 10, so as to more effectively conduct the heat generated by the surface mount device 40 to the pad body 10. The welding surface 11 is opposite to the heat dissipation surface 12, and is the surface of the pad body 10 that directly contacts the PCB board or other carrier board.

[0050] On the basis that the above-mentioned pad body 10 is formed with a welding surface 11 and a heat dissipation surface 12 arranged opposite to each other, a plurality of first heat dissipation vias 13 penetrating the welding surface 11 and the heat dissipation surface 12 are arranged in an array on the pad body 10. The first heat dissipation vias 13 can provide an effective heat dissipation path for the pad body 10, so that after the heat is transferred to the pad body 10 through the welding surface 11, the pad body 10 can quickly transfer the heat to the heat dissipation surface 12 through the first heat dissipation vias 13, thereby improving the heat transfer efficiency between the pad body 10 and the air or the above-mentioned carrier board components, and effectively reducing the temperature of the surface mount device 40.

[0051] Based on the structural form of the above-mentioned pad body 10, the surface mount heat dissipation pad also includes a solder resist layer 20. The main purpose of the solder resist layer 20 is to protect the circuit structure on the PCB board and prevent the solder from overflowing during the welding process, thereby avoiding problems such as short circuit of the PCB board. At the same time, the solder resist layer 20 can also effectively confine the solder to a specific welding area to ensure that the solder can cover the welding surface 11 and fill the first heat dissipation via 13, thereby improving the heat transfer efficiency between the surface mount device 40 and the pad body 10 and ensuring the welding stability of the surface mount device 40.

[0052] It should be understood that the material generally used for the solder resist layer 20 is a polymer material. In some cases, resin is the main component of the solder resist layer 20. These polymer materials have good moisture resistance and temperature resistance and are non-conductive. Therefore, they can effectively protect the PCB board and prevent solder from flowing into areas where soldering is not required during the soldering process.

[0053] Please refer to the attached Figure 1-Figure 2 The solder resist layer 20 is located on the soldering surface 11 of the pad body 10 and is arranged around the edge area of ​​the soldering surface 11. It should be noted that the edge area of ​​the soldering surface 11 refers to the area near the edge of the soldering surface 11. The range of this area can usually be limited by the width of the solder resist layer 20. The solder resist layer 20 continuously arranged in the edge area of ​​the soldering surface 11 can define the layout area of ​​the solder on the soldering surface 11, and can constrain the solder in the area of ​​the soldering surface 11 surrounded by the solder resist layer 20, so as to avoid the overflow of liquid solder.

[0054] Through the above-mentioned arrangement, the filling of the first heat dissipation via 13 of the surface mount heat dissipation pad and the welding with the surface mount device 40 can be completed by only one tinning and one heating. In the actual process flow, the operator or organization needs to calculate the amount of solder used to fill the first heat dissipation via 13 and arranged on the welding surface 11, and after one tinning, arrange the tin material sufficient to fill the heat dissipation via and the welding surface 11 on the pad body 10. Because the amount of tin is larger than the amount used in the traditional tinning process, when the surface mount device 40 is subsequently placed on the heat dissipation pad, the surface mount device 40 will be supported by the solder, and as the solder liquefies during the subsequent heating, the liquid solder (liquid tin) will also fill and flow into each heat dissipation via. In the process, the liquid level of the liquid solder on the welding surface 11 gradually decreases, and because the solder mask 20 is protruding from the welding surface 11 of the pad body 10, the surface mount device 40 will eventually drop to the level of the solder mask 20 mounted on the solder mask 20. 0, so that the surface mount device 40 and the welding surface 11 cooperate to form a vacuum area that is connected to the external environment only through the first heat dissipation vias 13, and because the first heat dissipation vias 13 have been filled in the solder liquefaction process, therefore, under the action of atmospheric pressure, it is ensured that the tin material is "absorbed" by the vacuum area and will not flow out from the first heat dissipation vias 13, ensuring that the filling effect of the tin material can meet the heat dissipation requirements of the device, that is, on the basis of meeting the packaging requirements of the device, the process steps can be simplified to achieve the purpose of reducing costs and increasing efficiency, thereby reducing the number of subsequent heating and welding times, saving related process steps in the packaging process, reducing product production costs, and improving product support efficiency and shortening production cycles.

[0055] It is worth mentioning that in some embodiments, the PCB board will be placed on a heating plate through the heat dissipation surface 12 for heating and welding. Therefore, in the above-mentioned heating process, the temperature of the end of the first heat dissipation via 13 close to the heat dissipation surface 12 will be higher than the end close to the welding surface 11. Therefore, the end of the first heat dissipation via 13 with a relatively higher temperature can also attract liquid solder, so that the liquid solder can be attracted by the fourth heat dissipation via in addition to being affected by atmospheric pressure, so as to further ensure that the liquid tin is in a state of completely filling the first heat dissipation via 13 without overflowing.

[0056] Please continue to refer to the attached Figure 1-Figure 2It can be understood that the aperture and spacing of the first heat dissipation vias 13 have a direct impact on the heat dissipation effect of the heat dissipation pad. The aperture of the first heat dissipation vias 13 should not be too large to avoid increasing the manufacturing cost and process difficulty, and should not be too small to avoid affecting the heat dissipation effect. In this example, the diameter of the first heat dissipation vias 13 is set to 0.2mm-0.3mm, preferably 0.25mm, to ensure that the liquid solder can flow smoothly into the first heat dissipation vias 13, and after the solder is re-solidified, it can play a role in transferring the heat of the solder located on the welding surface 11 to one end of the heat dissipation surface 12 of the pad body 10.

[0057] Optionally, a material with good thermal conductivity can be arranged in the first heat dissipation via 13 to cooperate with the solder to further improve the heat transfer efficiency. For example, a heat dissipation copper layer 70 can be arranged around the first heat dissipation via 13, so that when the solder in the first heat dissipation via 13 receives heat, the solder can not only transfer the heat toward the heat dissipation surface 12, but also exchange heat with the heat dissipation copper layer 70, thereby improving the heat transfer speed through copper or other metals with good thermal conductivity, so as to quickly discharge the heat accumulated in the heat dissipation pad, thereby preventing the surface mount device 40 from accumulating heat on the heat dissipation pad during the continuous heating process, and ensuring that the surface mount device 40 can operate normally.

[0058] In one embodiment, the thickness of the heat dissipation copper layer 70 is 0.025 mm. It should be noted that since this embodiment requires a heat dissipation copper layer 70 with a certain thickness to be set in the first heat dissipation via 13, in order to ensure that the tin material filled in the first heat dissipation via 13 can meet the heat dissipation requirements of the surface mount device 40, the aperture size of the first heat dissipation via 13 also needs to reserve sufficient space for the heat dissipation copper layer 70.

[0059] For example, when the heat dissipation copper layer 70 is not provided in the first heat dissipation via 13, if the diameter of the solder in the first heat dissipation via 13 is to be maintained at 0.2 mm, the first heat dissipation via 13 needs to be opened to 0.2 mm. In the implementation mode in which the heat dissipation copper layer 70 is provided in the first heat dissipation via 13, in order to allow the solder to still maintain a diameter size of 0.2 mm in the first heat dissipation via 13, the first heat dissipation via 13 needs to be set to 0.25 mm, so that after the heat dissipation copper layer 70 with a thickness of 0.025 mm is provided on the hole wall of the first heat dissipation via 13, the inner diameter of the hole still remains at a size of 0.2 mm.

[0060] It is worth mentioning that by setting the heat dissipation copper layer 70 in the first heat dissipation via 13, when the liquid tin flows into the first heat dissipation via 13, the first heat dissipation via 13 can also use the metal properties of the heat dissipation copper layer 70 to attract the liquid tin, so as to further improve the stability of the liquid tin in the first heat dissipation via 13.

[0061] Optionally, the first heat dissipation vias 13 of the present embodiment should all be opened in the area defined by the solder resist layer 20 so that the heat can be better transferred to the solder located in the first heat dissipation vias 13. In addition, in order to leave enough heat absorption space between the first heat dissipation vias 13 and avoid the heat between the first heat dissipation vias 13 affecting each other, resulting in a decrease in heat transfer efficiency, the present embodiment sets the hole wall spacing between any two adjacent first heat dissipation vias 13 to ≥0.3mm.

[0062] Of course, under the above-mentioned limited conditions, in order to ensure that more first heat dissipation vias 13 are set in a limited area to achieve a good heat dissipation effect, the first heat dissipation vias 13 can be arrayed on the pad body 10 under the constraint of a hole wall spacing of 0.3 mm to achieve a balance in a certain sense.

[0063] Furthermore, in order to prevent the heat transferred by the solder in the first heat dissipation via 13 arranged near the edge of the pad body 10 from affecting other related components in the PCB board, the present embodiment also sets the distance between the hole wall of the first heat dissipation via 13 and the edge of the pad body 10 to ≥0.3mm.

[0064] In addition, based on any of the above-mentioned embodiments, in order for the solder resist layer 20 to effectively provide a solder blocking function for the pad body 10 and prevent solder overflow, the solder resist layer 20, while surrounding the outer edge area of ​​the welding surface 11, also needs to constrain and limit its thickness dimension protruding from the welding surface 11 and its width dimension perpendicular to its extension direction on the welding surface 11.

[0065] The thickness of the solder resist layer 20 protruding from the soldering surface 11 is set to 0.01 mm-0.04 mm, preferably 0.03 mm, so that the solder resist layer 20 has a sufficient height to block the liquid tin accumulated on the soldering surface 11 .

[0066] Optionally, the width of the solder resist layer 20 is set to 0.1 mm to prevent excessive tin accumulation on the soldering surface 11 from easily crossing the solder resist layer 20 and causing solder overflow.

[0067] Please continue to refer to the attached Figure 1-Figure 2 This embodiment further provides a semiconductor package, which, based on the surface mount heat dissipation pad provided in any of the above embodiments, further includes:

[0068] The substrate 30 is used to provide support and protection for the surface mount device 40, and can also provide a conductive path to achieve electrical connection between the surface mount device 40 and the external circuit. The substrate 30 can be a composite of multiple materials, such as metal, ceramic or composite materials, etc., depending on the specific application scenario and requirements. For example, in the application scenario of the power amplifier device of this embodiment, the substrate 30 needs to have good thermal conductivity to ensure that heat can be dissipated in time to avoid overheating and damage to the device. At the same time, the substrate 30 also needs to have a certain mechanical strength and stability to withstand the vibration and impact generated by the device during operation.

[0069] In some embodiments, the substrate 30 can be configured as a PCB board, thereby reducing the difficulty of installing the surface-mount device 40 and other related devices, and also improving the space utilization of the substrate 30, making the power amplifier module structure more compact and more integrated.

[0070] The pad body 10 provided in the above embodiment is embedded in one side of the substrate 30, so that the pad body 10 can be regarded as forming an integral plate with the substrate 30, the heat dissipation surface 12 of the pad body 10 faces the substrate 30, and the welding surface 11 is flush with the surface of one side of the substrate 30, so as to ensure that the surface mount device 40 can be smoothly soldered to the PCB board using surface mounting technology and connected to the pad body 10 through solder.

[0071] Optionally, the pad body 10 can be set on the substrate 30 through different process methods, including but not limited to welding process, bonding process, pressing process, etc. This embodiment does not make strict limitations and requirements on this, and only needs to ensure that the welding surface 11 of the pad body 10 is set flush with the surface of the substrate 30.

[0072] Furthermore, a plurality of second heat dissipation vias 31 corresponding to and connected to the first heat dissipation holes are arranged in an array on the substrate 30. The second heat dissipation vias 31 pass through two opposite side surfaces of the substrate 30. The first heat dissipation vias 13 are connected to the second heat dissipation vias 31 one by one, so that the solder can flow into the second heat dissipation vias 31 through the first heat dissipation vias 13 after liquefaction, and completely fill the first heat dissipation vias 13 and the second heat dissipation vias 31, so as to dissipate heat from the side of the substrate 30 away from the pad body 10, rather than just transferring heat to the substrate 30 through the solder in the first heat dissipation vias 13.

[0073] Based on the above embodiment, the semiconductor package also includes the surface mount device 40 mentioned above. The surface mount device 40 is provided with a heat dissipation pin 41 on one side thereof for welding with the pad body 10 (i.e., the side thereof for mounting with the substrate 30). The heat dissipation pin 41 can effectively transfer the heat generated by the surface mount device 40. In one embodiment, a plurality of heat dissipation pins 41 are provided. The plurality of heat dissipation pins 41 can increase the heat dissipation path of the surface mount device 40, so that when the surface mount device 40 is welded to the pad body 10 through the heat dissipation solder foot, the heat transfer efficiency between the surface mount device 40 and the heat dissipation pad is ensured.

[0074] Please refer to the attached Figure 1-Figure 3 As described above for the mounting process of the surface mount device 40, during the heating process of the substrate 30, the solder on the pad body 10 will gradually liquefy and flow into the second heat dissipation via 31 through the first heat dissipation via 13 until the first heat dissipation via 13 and the second heat dissipation via 31 are filled, and the liquid tin on the welding surface 11 will be flush with the solder resist layer 20 or slightly lower than the thickness of the solder resist layer 20. In this way, the side of the surface mount device 40 provided with the heat dissipation pin 41 will eventually drop to a state where it is mounted on the substrate 30 through the solder resist layer 20. The surface mount device 40, the solder resist layer 20 and the welding surface 11 are surrounded to form a cavity structure. Since the welding surface 11 and the first heat dissipation hole and the second heat dissipation hole are filled with solder in this state, air can only enter the cavity structure through the second heat dissipation via 31 and the first heat dissipation via 13. However, due to the presence of solder, the solder cannot overflow from the second heat dissipation hole under the action of the atmosphere, so that air cannot enter the cavity structure, thereby ensuring that the solder will not overflow, so that the solder filling effect meets the packaging requirements and heat dissipation requirements of the semiconductor package.

[0075] Please continue to refer to the attached Figure 1-Figure 2 The semiconductor package also includes a bottom heat dissipation pad 50, which is embedded in the side of the substrate 30 away from the pad body 10 and is consistent with the pad body 10. The bottom heat dissipation pad 50 can be but is not limited to being set on the side of the substrate 30 away from the pad body 10 using the above-mentioned process method to form a whole with the substrate 30.

[0076] A plurality of third heat dissipation vias 51 corresponding to and connected to the second heat dissipation holes are arranged in an array on the bottom heat dissipation pad 50. The first heat dissipation vias 13, the second heat dissipation vias 31 and the third heat dissipation vias 51 are connected one by one, so that during the heating process of the substrate 30, the liquid tin can flow into the third heat dissipation vias 51 through the first heat dissipation vias 13 and the second heat dissipation vias 31, and connect to the bottom heat dissipation pad 50 after solidification. By further arranging the bottom heat dissipation pad 50 on the side of the substrate 30 away from the pad body 10, the heat dissipation surface 12 located on the bottom side of the substrate 30 (the side away from the pad body 10) can be effectively increased, so that the heat can pass through the heat dissipation vias and be transferred to the bottom heat dissipation pad 50, so as to be dissipated to the outside through the bottom heat dissipation pad 50, and the heat does not need to be dissipated only through the solder located in the heat dissipation vias, thereby improving the heat dissipation efficiency of the semiconductor package.

[0077] Based on the above principle, in order to further improve the heat dissipation efficiency of the substrate 30 (PCB board), the substrate 30 in this embodiment further includes at least two substrate layers 32 and inner pads 33. Among them, the pad body 10 is embedded in one of the substrate layers 32, and in the above embodiment including the bottom heat dissipation pad 50, the bottom heat dissipation pad 50 and the pad body 10 are respectively embedded in two independent substrate layers 32. The inner pad 33 is arranged between any two adjacent substrate layers 32, and the second heat dissipation via 31 runs through each substrate layer 32 and the inner pad 33.

[0078] In this embodiment, the number of substrate layers 32 can be determined according to the design requirements of the semiconductor package and the heat dissipation requirements of the surface mount device 40, and can be set to two, three, four, etc., and when the substrate layers 32 are set to two, the inner pad 33 is set to one, and when the substrate layers 32 are set to three, the inner pad 33 is set to two, and so on. That is, it can be understood that the number of substrate layers 32 is n, where n≥2, and the number of inner pads 33 is n-1.

[0079] Of course, in the PCB board, the substrate layers 32 can also be integrally formed. It is only necessary to place the inner pads 33 therein at one time during the processing of the substrate 30 so that the inner pads 33 are separated by the substrate layer 32 .

[0080] In this way, when heat is transferred to the solder in the second heat dissipation via 13 through the solder in the first heat dissipation via 13, the heat can not only be transferred in the direction away from the first heat dissipation via 13 (the direction close to the third heat dissipation via 51), but also be dispersed to the inner layer pad 33 to alleviate the heat transfer burden of each heat dissipation via and avoid excessive heat accumulation in the heat dissipation vias.

[0081] It should be understood that in order to ensure the effective connection between the surface mount device 40 and other related devices, the semiconductor package also includes a surface mount pad 60, wherein the surface mount pad 60 is provided in plurality, and the plurality of surface mount pads 60 are arranged at intervals on one side of the substrate 30 where the pad body 10 is provided and surround the periphery of the welding surface 11. Correspondingly, the surface mount device 40 is also provided with a plurality of functional pins 42, and each functional pin 42 is respectively connected to each surface mount pad 60 by solder.

[0082] In the above-mentioned embodiment in which the heat dissipation copper layer 70 is provided, the heat dissipation copper layer 70 may be provided in the first heat dissipation via 13 , the second heat dissipation via 31 , and the third heat dissipation via 51 that are interconnected.

[0083] Please refer to the attached Figure 3 This embodiment also provides a surface mounting method, which is applied to the above-mentioned semiconductor package. The surface mounting method includes the steps of:

[0084] S10, placing solder paste in a receiving groove formed by the welding surface 11 and the solder resist layer 20. The receiving groove is a part of the subsequent cavity structure, and the solder paste can generally be placed by opening a window with a steel mesh and brushing tin.

[0085] S20, placing the surface mount device 40 on the substrate 30 and making the heat dissipation pin 41 correspond to the receiving groove. Since the amount of solder paste is larger than the space defined by the soldering surface 11 and the solder resist layer 20, the solder paste will be located higher than the solder resist layer 20 after brushing, so that the surface mount device 40 is supported by the solder paste in this state;

[0086] S30, heating the solder paste and liquefying the solder paste, the liquid tin gradually fills the receiving groove and flows to the second heat dissipation vias 31 through the first heat dissipation vias 13 under the action of gravity, so that the liquid level of the liquid tin in the receiving groove gradually decreases to be flush with the solder resist layer 20, and at the same time as the liquid tin fills the first heat dissipation vias 13 and the second heat dissipation vias 31, the surface mount device 40 is mounted on the solder resist layer 20;

[0087] S40, cooling and solidifying the liquid tin to complete the packaging process of the semiconductor package.

[0088] It should be noted that in order for the solder paste (solder) to accurately fill the heat dissipation vias and the cavity structure formed between the surface mount device 40 and the welding surface 11 after liquefaction, the operator or organization should calculate the volume of the above-mentioned cavity structure and each heat dissipation via before brushing tin, and after calculating the above-mentioned volume, further calculation is required based on the ratio between the tin and the flux in the solder paste, so that after the solder paste is liquefied and the flux is discharged, the remaining tin can meet the above-mentioned filling requirements.

[0089] In the above implementation, taking the case where the ratio of tin material to flux in the solder paste is 1:1 as an example, the calculation of the amount of solder paste should satisfy the following relationship:

[0090] V={πr2*h*n+(a-2w)*(b-2w)*e}*2.

[0091] Among them, the length of the pad body 10 is a, the width of the pad body 10 is b, the width of the solder resist layer 20 is w, the thickness of the solder resist layer 20 is e, the radius of the heat dissipation via (including the first heat dissipation via 13, the second heat dissipation via 31 and the third heat dissipation via 51) is r, the number of heat dissipation vias is n, and the thickness of the substrate 30 is h.

[0092] It should be understood that in order to meet the demand for solder paste usage, in the implementation of brushing tin with a steel mesh, the thickness of the steel mesh should also be calculated according to the amount of solder paste, and the calculation of the thickness of the steel mesh should satisfy the following formula:

[0093] t=V / {(a-2w)*(b-2w)}.

[0094] In the description herein, it should be understood that the terms "upper", "lower", "left", "right", etc., and other directions or positional relationships are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0095] In the description of this specification, the description with reference to the terms "an embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0096] In addition, it should be understood that although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0097] The technical principle of the present invention is described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific implementations of the present invention without paying creative labor, and these methods will fall within the scope of protection of the present invention.

Claims

1. A surface mount heat dissipation pad, characterized in that: include: A pad body (10), the pad body (10) being formed with a welding surface (11) and a heat dissipation surface (12) disposed opposite to each other, and the pad body (10) being provided with a plurality of first heat dissipation vias (13) penetrating the welding surface (11) and the heat dissipation surface (12) in an array; A solder resist layer (20), the solder resist layer (20) being located on the soldering surface (11) of the pad body (10) and being arranged around an edge region of the soldering surface (11).

2. The surface mount heat dissipation pad according to claim 1, characterized in that: The diameter of the first heat dissipation via hole (13) is set to 0.2 mm-0.3 mm; A heat dissipation copper layer (70) is also arranged around the first heat dissipation via hole (13), and the thickness of the heat dissipation copper layer (70) is 0.025 mm.

3. The surface mount heat dissipation pad according to claim 1 or 2, characterized in that: The distance between the hole wall of the first heat dissipation via (13) and the edge of the pad body (10) is set to be ≥0.3 mm; The hole wall spacing between any two adjacent first heat dissipation vias (13) is set to be ≥0.3 mm.

4. The surface mount heat dissipation pad according to claim 1, characterized in that: The thickness of the solder resist layer (20) protruding from the soldering surface (11) is set to be 0.01 mm-0.04 mm.

5. The surface mount heat dissipation pad according to claim 1, characterized in that: The width dimension of the solder resist layer (20) is set to 0.1 mm.

6. A semiconductor package, characterized in that: include: The surface mount heat dissipation pad as claimed in any one of claims 1 to 5; A substrate (30), wherein the pad body (10) is embedded on one side of the substrate (30), the heat dissipation surface (12) of the pad body (10) faces the substrate (30), and the welding surface (11) is flush with the surface of one side of the substrate (30), and the substrate (30) is also provided with a plurality of second heat dissipation vias (31) arranged in an array and corresponding to and connected to each of the first heat dissipation holes, and the second heat dissipation vias (31) penetrate two opposite side surfaces of the substrate (30); and A surface mount device (40) is provided with a heat dissipation pin (41); a side surface of the surface mount device (40) provided with the heat dissipation pin (41) is mounted on the substrate (30) through the solder resist layer (20), so that the surface mount device (40), the solder resist layer (20) and the welding surface (11) enclose a cavity structure, the cavity structure is connected with the first heat dissipation via (13) and the second heat dissipation via (31), and the cavity structure and the first heat dissipation via (13) and the second heat dissipation via (31) are all filled with solder.

7. The semiconductor package according to claim 6, wherein: Also includes: A bottom heat dissipation pad (50) is embedded in a side of the substrate (30) away from the pad body (10), and a plurality of third heat dissipation vias (51) corresponding to and connected to each of the second heat dissipation holes are arranged in an array on the bottom heat dissipation pad (50).

8. The semiconductor package according to claim 6 or 7, characterized in that: The substrate (30) comprises: A substrate layer (32), wherein the substrate layers (32) are provided in at least two pieces, and the pad body (10) is embedded in one of the substrate layers (32); and The inner layer pad (33) is arranged between any two adjacent substrate layers (32), and the second heat dissipation via (31) penetrates each substrate layer (32) and the inner layer pad (33).

9. The semiconductor package according to claim 6, wherein: Also includes: A surface mount pad (60), wherein the surface mount pad (60) is provided in plurality, and the plurality of surface mount pads (60) are arranged at intervals on a side of the substrate (30) provided with the pad body (10) and surround the outer periphery of the welding surface (11); The surface mount device (40) is also provided with a plurality of functional pins (42), and each functional pin (42) is connected to a corresponding surface mount pad (60) via solder.

10. A surface mounting method, characterized in that: Applied to the semiconductor package as claimed in any one of claims 6 to 9, the semiconductor surface mounting method comprises the steps of: S10, placing solder paste in a receiving groove formed by the welding surface (11) and the solder resist layer (20); S20, arranging the surface mount device (40) on the substrate (30) and making the position of the heat dissipation pin (41) correspond to the receiving groove; S30, heating the solder paste and liquefying the solder paste, so that the liquid tin gradually fills the receiving groove and flows to the second heat dissipation via (31) through each of the first heat dissipation vias (13) under the action of gravity, so that the liquid level of the liquid tin in the receiving groove gradually decreases to be flush with the solder resist layer (20), and while filling each of the first heat dissipation vias (13) and the second heat dissipation vias (31), the surface mount device (40) is mounted on the solder resist layer (20); S40, cooling and solidifying the liquid tin.

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