Circuit board assemblies and electronic devices

Abstract

The present application provides a circuit board assembly and electronic device, wherein the circuit board assembly includes a circuit board and a heating element, wherein the heating element is soldered to the circuit board via solder; the heating element includes a glue-filled area and a non-glue-filled area on the side facing the circuit board, wherein the non-glue-filled area is aligned with a high-heating area on the heating element. The circuit board assembly and electronic device provided by the present application, by designing the glue-filled and non-glue-filled areas, avoid the problem of thermal fatigue of the solder joints caused by thermal expansion of the glue in the high-heating area, while also ensuring the mechanical reliability of the solder joints.

Description

Technical Field

[0001] This application relates to the field of electronic information technology, and in particular to a circuit board assembly and an electronic device. Background Technology

[0002] Thermal fatigue failure of chip solder joints is a critical issue that causes electronic products to fail after prolonged use. It can easily trigger public opinion, impacting product quality reputation and increasing service costs. In particular, with the trend towards high-density and high-performance electronic products, chip heat generation increases. While the adhesive filling the chip's underside is typically used to protect the mechanical reliability of the solder joints, the adhesive usually has a high coefficient of thermal expansion. Thermal expansion causes deformation of the solder balls, posing a significant challenge to the thermal fatigue reliability of the solder joints. Summary of the Invention

[0003] The purpose of this application is to provide a circuit board assembly and electronic device to solve the problem of thermal fatigue failure of solder joints caused by chip heating in the prior art.

[0004] The first aspect of this application provides a circuit board assembly, which includes a circuit board and a heating element, the heating element being soldered to the circuit board; the side of the heating element facing the circuit board includes a glue-filled area and a non-glue-filled area, the non-glue-filled area being aligned with a high-heat area on the heating element.

[0005] The circuit board assembly provided in this application features a glue-filled area and a non-glue-filled area on the side of the heating element facing the circuit board. The non-glue-filled area is aligned with the high-heat-generating area on the heating element, and the glue-filled area is aligned with the low-heat-generating area on the heating element. No glue is filled between the non-glue-filled area and the circuit board, thus completely avoiding the problem of thermal fatigue of the solder joint caused by the thermal expansion of the glue located in the high-heat-generating area. Furthermore, by filling the glue only between the glue-filled area and the circuit board, the mechanical reliability of the solder joint can be ensured through the glue.

[0006] In one possible implementation, the circuit board and / or the heating element have a barrier structure at the location corresponding to the connection between the glue-filled area and the non-glue-filled area. This barrier structure separates the glue-filled area and the non-glue-filled area, preventing glue in the glue-filled area from flowing into the non-glue-filled area. This avoids the glue coming into contact with the high-heat area of ​​the heating element and expanding due to heat, thus preventing thermal fatigue of the solder joint.

[0007] In one possible implementation, the heating element has a plurality of solder joints spaced apart on the side facing the circuit board, and the barrier structure is disposed between some of two adjacent solder joints.

[0008] The multiple solder joints can be distributed in rectangular arrays, circular arrays, discrete arrays, etc. In this embodiment, the multiple solder joints are preferably distributed in a rectangular array. A certain distance can be maintained between adjacent solder joints in both the length and width directions of the heating element, allowing the barrier structure to be inserted between adjacent solder joints. This allows the barrier structure to fill the gaps between solder joints located in the glue-filled and non-glue-filled areas, and, in conjunction with the solder joints located between the glue-filled and non-glue-filled areas, effectively block the glue in the glue-filled area, preventing the glue from flowing into the non-glue-filled area.

[0009] In one possible implementation, a first distance is spaced between two adjacent solder joints, and a second distance is spaced between the circuit board and the heating element; in a direction parallel to the interface between the circuit board and the heating element, the width of the barrier structure is less than or equal to the first distance; in a direction perpendicular to the interface between the circuit board and the heating element, the thickness of the barrier structure is less than or equal to the second distance, thereby facilitating the insertion of the barrier structure between the solder joints.

[0010] In one possible implementation, the barrier structure is made of quartz or glass fiber.

[0011] The barrier structure can be made of materials that are resistant to high temperatures, have insulation properties, and have an extremely low coefficient of thermal expansion, such as quartz or glass fiber.

[0012] In one possible implementation, the barrier structure is an elongated columnar or tubular structure. Specifically, it can be a capillary tube, capillary column, etc. This elongated barrier structure can penetrate from one end of the heating element in a single direction to the other end of the heating element at the boundary between the glue-filled area and the non-glue-filled area, thereby achieving the barrier of the glue in the glue-filled area.

[0013] In one possible implementation, the cross-sectional shape of the barrier structure along the width direction is circular, elliptical, rectangular, or polygonal.

[0014] In one possible implementation, the barrier structure is made of metal, and the barrier structure is soldered to the circuit board or heating element, with a gap between it and the solder joint.

[0015] The barrier structure of this metal material can be pre-welded onto the heating element or circuit board, and then the heating element or circuit board with the barrier structure is welded and assembled. In other words, the barrier structure can be formed during the on-line manufacturing process of the heating element or circuit board; offline assembly only requires welding the heating element or circuit board with the barrier structure, eliminating the need for a separate process to install the barrier structure, thus improving production efficiency. Furthermore, the barrier structure directly welded onto the heating element or circuit board offers more stable connection reliability, effectively preventing adhesive from flowing into non-filled areas, and the metal material barrier structure has good heat dissipation performance, which is beneficial for heat dissipation from the heating element.

[0016] In one possible implementation, the barrier structure is made of nickel silver or stainless steel.

[0017] In one possible implementation, the barrier structure is a strip structure, and at least two barrier structures are provided, with adjacent two barrier structures being parallel to each other, and the non-filled area being formed between adjacent two barrier structures.

[0018] A strip of unfilled area can be formed between two parallel barrier structures. This strip of unfilled area can cover a large area of ​​high-heat-generating zone. By not filling the unfilled area with glue, the problem of thermal fatigue of the solder joint caused by the thermal expansion of the glue in the high-heat-generating zone can be avoided.

[0019] In one possible implementation, both ends of the barrier structure extend to the edge of the heating element or the circuit board. This facilitates the installation and positioning of the barrier structure, ensuring its installation accuracy on the heating element or the circuit board.

[0020] In one possible implementation, the barrier structure is a ring structure, and the non-filled area is formed on the inner side of the barrier structure.

[0021] The outer perimeter of the ring is a glue-filling area, which can avoid the problem of thermal fatigue of the solder joint caused by the thermal expansion of the glue in the high-heat area, and also ensure the mechanical reliability of the solder joint.

[0022] In one possible implementation, the circuit board and / or the heating element are coated with a non-wetting material at locations corresponding to the connections between the filled and non-filled areas. This non-wetting material reduces the surface energy at the boundary, thereby achieving non-wetting of the filler, isolating the adhesive, and preventing the adhesive from flowing from the filled area to the non-filled area.

[0023] In one possible implementation, the non-wetting material is a glass fiber coating.

[0024] In one possible implementation, the circuit board and / or the heating element are provided with continuous pads at locations corresponding to the positions where they connect to the glue-filled area and the non-glue-filled area, and the continuous pads are structured to extend continuously along a set direction; the solder is welded to the continuous pads to form a barrier structure.

[0025] Among them, the continuous pad is a one-piece long strip pad, or a long strip pad formed by connecting multiple dot-shaped pads, so that the continuous pad has a long welding surface for connecting with the solder. After the solder is welded to the continuous pad, the solder can form a continuous solder wall on the continuous pad, which can achieve the barrier against adhesive.

[0026] In one possible implementation, one of the circuit board and the heating element is provided with the continuous pad, and the other is provided with a plurality of dot-shaped pads. The area of ​​the dot-shaped pads is smaller than the area of ​​the continuous pad. Along the thickness direction of the circuit board, the projection of one continuous pad coincides with the projection of the plurality of dot-shaped pads, and the continuous pad and the plurality of dot-shaped pads are connected by solder. The number and position of the dot-shaped pads can be flexibly adjusted according to the actual arrangement of the continuous pads, the circuit board, and the heating element, providing high design flexibility.

[0027] In one possible implementation, the continuous pads are elongated strips extending in a straight line, and at least two continuous pads are arranged in parallel, forming a strip-shaped unfilled area between adjacent continuous pads. This strip-shaped unfilled area can cover a large area of ​​high-heat-generating regions. By not filling the unfilled areas with adhesive, the problem of thermal fatigue of the solder joints caused by thermal expansion of the adhesive in high-heat-generating regions can be avoided.

[0028] In one possible implementation, the shape of the non-filled area is rectangular, triangular, circular, or polygonal.

[0029] In one possible implementation, the heating element is a chip.

[0030] A second aspect of this application also provides an electronic device that includes the circuit board assembly provided in the first aspect of this application.

[0031] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0032] Figure 1 This is a diagram illustrating the deformation of solder balls caused by the thermal expansion of adhesive in existing technologies.

[0033] Figure 2 A side view of a circuit board assembly provided in the first embodiment of this application;

[0034] Figure 3 This is a schematic diagram (a) showing the heating element facing the circuit board side in the first embodiment of this application;

[0035] Figure 4 This is a schematic diagram (II) showing the heating element facing the circuit board side in the first embodiment of this application;

[0036] Figure 5 A side view of a circuit board assembly provided in a second embodiment of this application;

[0037] Figure 6 This is a schematic diagram of the heating element facing the circuit board side in the second embodiment of this application;

[0038] Figure 7 A side view of a circuit board assembly provided in a third embodiment of this application;

[0039] Figure 8 This is a schematic diagram (a) showing the heating element facing the circuit board side in the third embodiment of this application;

[0040] Figure 9 This is a schematic diagram (II) showing the heating element facing the circuit board side in the third embodiment of this application;

[0041] Figure 10 A side view of the circuit board assembly provided in the fourth embodiment of this application;

[0042] Figure 11 This is a schematic diagram of the heating element facing the circuit board side in the fourth embodiment of this application;

[0043] Figure 12 A side view (a) of a circuit board assembly provided in the fifth embodiment of this application;

[0044] Figure 13 A side view (ii) of the circuit board assembly provided in the fifth embodiment of this application;

[0045] Figure 14 A side view (iii) of the circuit board assembly provided in the fifth embodiment of this application;

[0046] Figure 15 This is a schematic diagram (a) showing the heating element facing the circuit board side in the fifth embodiment of this application;

[0047] Figure 16 This is a schematic diagram (II) showing the heating element facing the circuit board side in the fifth embodiment of this application.

[0048] Figure label:

[0049] 10-chip;

[0050] 20-PCB board;

[0051] 30 - Welding balls;

[0052] 40-Glue;

[0053] 1-Heating element;

[0054] 11-Glue filling area;

[0055] 12 - Non-filled area;

[0056] 13-High fever area;

[0057] 14 - Dividing line;

[0058] 2-Circuit board;

[0059] 3-Glue;

[0060] 4- Solder joint;

[0061] 5a-Barrier structure;

[0062] 5b - Barrier structure;

[0063] 5c1 - Continuous pads;

[0064] 5c2 - Dot pad;

[0065] 5c3 - Solder wall;

[0066] 5c4 - Solder mask layer;

[0067] 6- Non-wetting materials;

[0068] h1 - First distance;

[0069] h2 - Second distance.

[0070] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0071] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0072] In the description of this application, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple" refers to two or more; the terms "connected," "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0073] In electronic products such as mobile phones and computers, chips are typically soldered onto circuit boards using solder. To ensure the mechanical reliability of the solder joints, adhesive is used between the chip and the circuit board to distribute the mechanical impact on the solder joints. Adhesives have varying coefficients of thermal expansion. If a low-coefficient adhesive (such as encapsulation-grade adhesive or non-flowing adhesive) is used between the chip and the circuit board, the chip may be difficult to repair, significantly increasing repair costs. If a high-coefficient adhesive is used, the adhesive will expand when heated, exerting force on the solder joint, causing deformation of the solder balls and leading to thermal fatigue, which poses a significant challenge to the reliability of the solder joint. Figure 1 This is a diagram illustrating the deformation of solder balls caused by thermal expansion of the adhesive in existing technologies, such as... Figure 1 As shown, chip 10 and PCB board 20 are connected by solder balls 30, and glue 40 is filled between chip 10 and PCB board 20. The solder balls 30 are deformed by the thermal stress generated by the expansion of glue 40.

[0074] This application provides a circuit board assembly and an electronic device. The circuit board assembly is applied to an electronic device, which can be a mobile phone, tablet computer, desktop computer, laptop computer, handheld computer, notebook computer, ultra-mobile personal computer (UMPC), netbook, as well as cellular phone, personal digital assistant (PDA), augmented reality (AR) device, virtual reality (VR) device, artificial intelligence (AI) device, wearable device, in-vehicle device, smart home device and / or smart city device. The embodiments of this application do not impose any special limitations on the specific type of the electronic device.

[0075] The circuit board assembly includes a circuit board 2 and a heating unit. The heating element 1 is soldered to the circuit board 2. The side of the heating element 1 facing the circuit board 2 includes a glue-filled area 11 and a non-glue-filled area 12. The non-glue-filled area 12 is aligned with the high-heat area 13 on the heating element 1.

[0076] During operation, the heating element 1 typically has a high-heating area 13 and a low-heating area. If the adhesive 3 is filled at a position aligned with the high-heating area 13, the higher heat from the high-heating area 13 will cause the adhesive 3 to expand due to heat, which will in turn generate significant thermal stress on the solder joint 4 located in the high-heating area 13, leading to thermal fatigue of the solder joint 4. If the adhesive 3 is filled at a position aligned with the low-heating area, the thermal stress generated by the adhesive 3 on the solder joint 4 in the low-heating area is smaller, and thermal fatigue is less likely to occur.

[0077] Therefore, in this embodiment, as Figures 2 to 4 As shown, a filling area 11 and a non-filling area 12 are designed on the side of the heating element 1 facing the circuit board 2. The non-filling area 12 is aligned with the high-heat area 13 on the heating element 1, and the filling area 11 is aligned with the low-heat area on the heating element 1. No glue 3 is filled between the non-filling area 12 and the circuit board 2, thereby completely avoiding the problem of thermal fatigue of the solder joint 4 caused by the thermal expansion of the glue 3 located in the high-heat area 13. In addition, by filling the glue 3 only between the filling area 11 and the circuit board 2, the mechanical reliability of the solder joint 4 can be guaranteed by the glue 3.

[0078] Therefore, the circuit board assembly provided in this application embodiment, by designing the glue-filling area 11 and the non-glue-filling area 12, not only avoids the problem of thermal fatigue of the solder joint 4 caused by the thermal expansion of the glue 3 located in the high-heat area 13, but also ensures the mechanical reliability of the solder joint 4.

[0079] The glue-filled area 11 and the non-glue-filled area 12 constitute a portion of the surface area of ​​the heating element 1. Specifically, as shown... Figure 3 As shown, the non-filled area 12 can be a long strip-shaped area that completely covers the width or length of the heating element 1, so that only the filling areas 11 located on both sides of the non-filled area 12 need to be filled with glue 3, which facilitates the glue application 3 operation. Furthermore, as... Figure 4 As shown, the non-filled area 12 can also be a small part of the heating element 1. The length and width of the non-filled area 12 are smaller than the length and width of the heating element 1. The non-filled area 12 is surrounded by the filled area 11. By filling the non-filled area 12 with glue 3, the mechanical reliability of the solder joint 4 can be effectively guaranteed.

[0080] Specifically, the heating element 1 can be a chip, or other components with high heat output. In this embodiment, the heating element 1 is preferably a chip.

[0081] As a specific implementation method, such as Figure 5 and Figure 6 As shown, the circuit board 2 and / or the heating element 1 are provided with a barrier structure 5a at the location corresponding to the connection between the glue-filled area 11 and the non-glue-filled area 12.

[0082] The glue-filled area 11 and the non-glue-filled area 12 constitute a portion of the surface area of ​​the heating element 1. The boundary line 14 separating the glue-filled area 11 and the non-glue-filled area 12 is located at the junction of the glue-filled area 11 and the non-glue-filled area 12. The barrier structure 5a can be disposed on the circuit board 2 or the heating element 1, and is located at a position aligned with the boundary line 14. This barrier structure 5a can separate the glue-filled area 11 and the non-glue-filled area 12, preventing the glue 3 in the glue-filled area 11 from flowing into the non-glue-filled area 12. This avoids the glue 3 from contacting the high-heat area 13 of the heating element 1 and expanding due to heat, thus preventing thermal fatigue of the solder joint 4.

[0083] It should be noted that before applying adhesive 3, the heating element 1, such as the chip, can be soldered onto the circuit board 2. The solder joint 4 between the chip and the circuit board 2 can maintain a certain gap between the chip and the circuit board 2. Then, adhesive 3 can be filled between the chip and the circuit board 2 from the side through this gap, so that adhesive 3 only fills the filling area 11. Through the blocking structure 5a, the adhesive 3 in the filling area 11 can be prevented from flowing to the non-filling area 12.

[0084] Among them, the heating element 1 has multiple solder points 4 spaced apart on the side facing the circuit board 2, and the barrier structure 5a is disposed between some of the adjacent solder points 4.

[0085] Multiple solder points 4 can be distributed in rectangular arrays, circular arrays, discrete arrays, etc. In this embodiment, the multiple solder points 4 are preferably distributed in a rectangular array. In the length and width directions of the heating element 1, a certain distance can be maintained between two adjacent solder points 4, so that the barrier structure 5a can be inserted between two adjacent solder points 4. In this way, the barrier structure 5a can fill the gap between the solder points 4 located between the glue-filling area 11 and the non-glue-filling area 12, and together with the solder points 4 located between the glue-filling area 11 and the non-glue-filling area 12, it can effectively block the glue 3 in the glue-filling area 11 and prevent the glue 3 from flowing to the non-glue-filling area 12.

[0086] Specifically, such as Figure 5 As shown, there is a first distance h1 between two adjacent solder joints 4, and a second distance h2 between the circuit board 2 and the heating element 1. In the direction parallel to the interface between the circuit board 2 and the heating element 1, the width of the barrier structure 5a is less than or equal to the first distance h1, and in the direction perpendicular to the interface between the circuit board 2 and the heating element 1, the thickness of the barrier structure 5a is less than or equal to the second distance h2, thereby facilitating the insertion of the barrier structure 5a between the solder joints 4.

[0087] In this embodiment, the material of the barrier structure 5a can be a high-temperature resistant, insulating, and extremely low coefficient of thermal expansion material, such as quartz or glass fiber. The barrier structure 5a can be a long tubular or columnar structure, such as a capillary or capillary column. The long strip-shaped barrier structure 5a can be inserted from one end of the heating element 1 in a single direction to the other end of the heating element 1 at the position of the boundary line 14 between the glue-filled area 11 and the non-glue-filled area 12, thereby achieving the barrier of the glue 3 in the glue-filled area 11.

[0088] The barrier structure 5a can be a strip structure, and at least two barrier structures 5a are provided, with adjacent barrier structures 5a parallel to each other, and a non-filled area 12 formed between adjacent barrier structures 5a. For example... Figure 6 As shown, the strip-shaped barrier structure 5a can extend to the edge of the heating element 1 at both ends in the length direction, so that a strip-shaped unfilled area is formed between two adjacent barrier structures 5a. This strip-shaped unfilled area can cover a large area of ​​high-heat area 13. By not filling the unfilled area with glue 3, the problem of thermal fatigue of solder joint 4 caused by thermal expansion of glue 3 in high-heat area 13 can be avoided.

[0089] Specifically, the cross-sectional shape of the barrier structure 5a along its width direction can be, but is not limited to, circular, elliptical, rectangular, or polygonal. In this embodiment, the barrier structure 5a is an elongated strip structure, and the width direction is the direction perpendicular to its length direction.

[0090] As a specific implementation method, such as Figures 7 to 9 As shown, the material of the barrier structure 5b can be metal. The barrier structure 5b is soldered to the circuit board 2 or the heating element 1, and a gap is formed between the barrier structure 5b and the solder joint 4.

[0091] In this embodiment, the metal barrier structure 5b can be pre-welded onto the heating element 1 or circuit board 2, and then the heating element 1 or circuit board 2 with the barrier structure 5b is welded and assembled. That is, the barrier structure 5b can be formed during the online manufacturing process of the heating element 1 or circuit board 2, and offline assembly of the heating element 1 or circuit board 2 with the barrier structure 5b is only required, eliminating the need for a separate process to install the barrier structure 5b, thereby improving production efficiency. Furthermore, the barrier structure 5b directly welded onto the heating element 1 or circuit board 2 has more stable connection reliability, effectively preventing the adhesive 3 from flowing into the non-filled area 12, and the metal barrier structure 5b has good heat dissipation performance, which is beneficial for heat dissipation of the heating element 1.

[0092] Specifically, the material of the barrier structure 5b can be, but is not limited to, nickel silver or stainless steel.

[0093] In this embodiment, at least two metal material barrier structures 5b can be provided, with adjacent barrier structures 5b parallel to each other, and a non-filled area 12 formed between adjacent barrier structures 5b. For example... Figure 8 As shown, the barrier structure 5b can extend to the edge of the heating element 1 at both ends in the length direction, so that a strip-shaped unfilled area is formed between two adjacent barrier structures 5b. This strip-shaped unfilled area can cover a large area of ​​high-heat area 13. By not filling the unfilled area with glue 3, the problem of thermal fatigue of solder joint 4 caused by thermal expansion of glue 3 in high-heat area 13 can be avoided.

[0094] In addition, such as Figure 9 As shown, the barrier structure 5b of this metallic material can also form a closed ring, such as a rectangular ring, a triangular ring, a circular ring, a polygonal ring, etc. Figure 9 The diagram shows a rectangular ring formed by a barrier structure 5b of the metal material. An unfilled area 12 is formed inside the rectangular ring, which is aligned with the high-heat area 13 on the heating element 1. The outer perimeter of the rectangular ring is a filler area 11 for filler 3. This avoids thermal fatigue of the solder joint 4 due to thermal expansion of the filler 3 in the high-heat area 13, while also ensuring the mechanical reliability of the solder joint 4. The area of ​​the annular region enclosed by the barrier structure 5b is similar to the area of ​​the high-heat area 13. This serves two purposes: firstly, it blocks the filler near the high-heat area 13, preventing thermal fatigue of the solder joint 4 due to thermal expansion; secondly, it reduces the area covered by the annular region enclosed by the barrier structure 5b, allowing filler to be used in areas away from the high-heat area 13, thus improving the mechanical reliability of the solder joint 4.

[0095] It should be noted that the aforementioned annular barrier structure 5b can have its inner non-filled area 12 shaped as a rectangle, triangle, circle, or polygon. In actual production, the position of the barrier structure 5b and the area of ​​the annular region enclosed by the barrier structure 5b can be determined according to the position and area of ​​the high-heat area 13 on the heating element 1, thereby meeting the application requirements of different heating elements 1.

[0096] As a specific implementation method, such as Figure 10 and Figure 11As shown, the circuit board 2 and / or the heating element 1 are coated with a non-wetting material 6 at the location corresponding to the connection between the filling area 11 and the non-filling area 12. This "connection location" is the boundary that the adhesive 3 can form between the filling area 11 and the non-filling area 12. As explained above, the location where the filling area 11 and the non-filling area 12 connect is the dividing line 14 that separates the filling area 11 and the non-filling area 12. The circuit board 2 and / or the heating element 1 are coated with a non-wetting material 6 at the location covering the dividing line 14, and the wetting angle of the non-wetting material 6 is greater than 90°. The non-wetting material 6 can reduce the surface energy at the boundary. Under heat, the adhesive on the circuit board 2 and / or the heating element 1 at the boundary tends to flow towards the high-heat area 13. By coating the boundary with the non-wetting material 6, there is a change in molecular force between the circuit board 2 and / or the heating element 1 and the coated non-wetting material 6, which changes the surface tension of the circuit board 2 and / or the heating element 1 at the coated non-wetting material 6. This reduces the surface energy of the circuit board 2 and / or the heating element 1 at the coated non-wetting material 6, thereby achieving non-wetting of the filler adhesive 3, isolating the adhesive 3, and preventing the adhesive 3 in the filler area 11 from flowing to the non-filler area 12.

[0097] Specifically, the non-wetting material 6 can be, but is not limited to, a glass fiber coating. In this embodiment, both the circuit board 2 and the heating element 1 are coated with the non-wetting material 6, thereby forming a film layer of a certain thickness on both the circuit board 2 and the heating element 1. After the heating element 1 is soldered onto the circuit board 2, the non-wetting material 6 film layer on the heating element 1 can be aligned with the non-wetting material 6 film layer on the circuit board 2. The properties of the non-wetting material 6 are used to form a barrier structure that can block the flow of the adhesive 3, preventing the adhesive 3 in the adhesive-filled area 11 from flowing to the non-adhesive-filled area 12.

[0098] Among them, such as Figure 11 As shown, the non-wetting material 6 can be coated along a straight line, that is, from one end of the heating element 1 or the circuit board 2 to the other end. There can be at least two such straight lines coated with the non-wetting material 6. The at least two straight lines are parallel to each other, and a strip-shaped non-filled area 12 is formed between the two adjacent straight lines. The strip-shaped non-filled area 12 can cover a large area of ​​high-heat area 13, which can avoid the problem of thermal fatigue of solder joint 4 in high-heat area.

[0099] Furthermore, the non-wetting material 6 can also form rings after coating, such as rectangular rings, triangular rings, circular rings, polygonal rings, etc. Figure 10As shown, in this embodiment, the non-wetting material 6 forms a rectangular ring after coating, and a non-filled area 12 is formed on the inner side of the rectangular ring. The rectangular ring is aligned with the high-heat area 13 on the heating element 1. The outer perimeter of the rectangular ring is a filling area 11 for filling with adhesive 3, which can avoid the problem of thermal fatigue of the solder joint 4 caused by the thermal expansion of the adhesive 3 located in the high-heat area 13, and also ensure the mechanical reliability of the solder joint 4.

[0100] As a specific implementation method, such as Figures 12 to 14 As shown, the circuit board 2 and / or the heating element 1 are provided with continuous pads 5c1 at the positions corresponding to the connection between the glue-filling area 11 and the non-glue-filling area 12. The continuous pads 5c1 are structures that extend continuously in a set direction. Solder can be welded to the continuous pads 5c1 to form a barrier structure for blocking the flow of glue 3.

[0101] Specifically, multiple small pads, referred to as dot pads 5c2, can be provided on both the heating element 1 and the circuit board 2. Solder forms solder joints 4 between corresponding dot pads 5c2 on the heating element 1 and the circuit board 2. A solder resist layer 5c4 can be provided between each solder joint 4 on the heating element 1 or the circuit board 2. The continuous pad 5c1 is a one-piece elongated pad, or an elongated pad formed by connecting multiple dot pads 5c2, so that the continuous pad 5c1 has a long welding surface for connecting with the solder. After the solder is welded to the continuous pad 5c1, the solder can form a continuous solder wall 5c3 on the continuous pad 5c1. The solder wall 5c3 can block the adhesive 3.

[0102] Specifically, such as Figure 12 As shown, continuous pads 5c1 can be provided only on circuit board 2, while multiple dot pads 5c2 are provided on heating element 1, opposite to the positions of the continuous pads 5c1 on circuit board 2. Along the thickness direction of circuit board 2, the projection of one continuous pad 5c1 coincides with the projection of the multiple dot pads 5c2, and the continuous pad 5c1 and the multiple dot pads 5c2 are connected by solder. Figure 13 As shown, it is also possible to provide continuous pads 5c1 only on the heating element 1, while providing multiple dot-shaped pads 5c2 on the circuit board 2 that are positioned opposite to the continuous pads 5c1 of the heating element 1. Figure 14As shown, continuous pads 5c1 can be provided on both the heating element 1 and the circuit board 2, with continuous pads 5c1 positioned opposite to those on the heating element 1. Each of these arrangement methods for the connecting pads can create a solder wall 5c3 between the heating element 1 and the circuit board 2, thus blocking the adhesive 3. Furthermore, the arrangement of these connecting pads can be flexibly adjusted according to the actual layout of the circuit board 2 and the heating element 1, enhancing the design flexibility of the pads on the circuit board 2 and the heating element 1, and demonstrating strong applicability.

[0103] Among them, Figure 15 As shown, the continuous pads 5c1 can be arranged in a straight line, that is, extending from one end of the heating element 1 or the circuit board 2 to the other end. There can be at least two such continuous pads 5c1 extending in a straight line. At least two continuous pads 5c1 are parallel to each other, and a strip-shaped non-filled area 12 is formed between adjacent two continuous pads 5c1. This strip-shaped non-filled area can cover a large area of ​​high-heat area 13. By not filling the non-filled area with glue 3, the problem of thermal fatigue of solder joint 4 caused by thermal expansion of glue 3 in high-heat area 13 can be avoided.

[0104] Furthermore, the continuous pad 5c1 can also be formed into a ring, such as a rectangular ring, a triangular ring, a circular ring, a polygonal ring, etc. Figure 16 As shown, in this embodiment, the continuous solder pad 5c1 can form a rectangular ring, with a non-filled area 12 formed on the inner side of the rectangular ring. The rectangular ring is aligned with the high-heat area 13 on the heating element 1. The outer perimeter of the rectangular ring is a filling area 11 for filling with adhesive 3, which can avoid the problem of thermal fatigue of the solder joint 4 caused by the thermal expansion of the adhesive 3 located in the high-heat area 13, and also ensure the mechanical reliability of the solder joint 4.

[0105] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A circuit board assembly, characterized in that, include: Circuit board; A heating element, which is soldered to the circuit board; The side of the heating element facing the circuit board includes a glue-filled area and a non-glue-filled area, and the non-glue-filled area is aligned with the high-heat area on the heating element. The circuit board and / or the heating element are provided with a barrier structure at the location corresponding to the connection between the glue-filled area and the non-glue-filled area. The heating element has multiple solder joints spaced apart on the side facing the circuit board, and the barrier structure is disposed between some adjacent solder joints. There is a first distance between two adjacent solder joints, and the width of the barrier structure is less than or equal to the first distance in a direction parallel to the interface between the circuit board and the heating element.

2. The circuit board assembly according to claim 1, characterized in that, A second distance is provided between the circuit board and the heating element; In the direction perpendicular to the interface between the circuit board and the heating element, the thickness of the barrier structure is less than or equal to the second distance.

3. The circuit board assembly according to claim 1 or 2, characterized in that, The barrier structure is made of quartz or glass fiber.

4. The circuit board assembly according to claim 1 or 2, characterized in that, The barrier structure is a slender columnar or tubular structure.

5. The circuit board assembly according to claim 4, characterized in that, The cross-sectional shape of the barrier structure along its width direction is circular, elliptical, rectangular, or polygonal.

6. The circuit board assembly according to claim 1 or 2, characterized in that, The barrier structure is made of metal and is welded to the circuit board or heating element, with a gap between it and the solder joint.

7. The circuit board assembly according to claim 6, characterized in that, The barrier structure is made of nickel silver or stainless steel.

8. The circuit board assembly according to any one of claims 1-3 and 5-7, characterized in that, The barrier structure is a strip structure, and at least two barrier structures are provided. Two adjacent barrier structures are parallel to each other, and a non-filled area is formed between two adjacent barrier structures.

9. The circuit board assembly according to claim 8, characterized in that, Both ends of the barrier structure extend to the edge of the heating element or the circuit board.

10. The circuit board assembly according to claim 6, characterized in that, The barrier structure is a ring structure, and the non-filled area is formed on the inner side of the barrier structure.

11. The circuit board assembly according to claim 1, characterized in that, The circuit board and / or the heating element are coated with a non-wetting material at the locations corresponding to the connections between the glue-filled area and the non-glue-filled area.

12. The circuit board assembly according to claim 11, characterized in that, The non-wetting material is a glass fiber coating.

13. The circuit board assembly according to claim 1, characterized in that, The circuit board and / or the heating element are provided with continuous pads at the locations corresponding to the positions where they are connected to the glue-filled area and the non-glue-filled area. The continuous pads are structures that extend continuously along a set direction. The solder is welded to the continuous pads to form a barrier structure.

14. The circuit board assembly according to claim 13, characterized in that, One of the circuit board and the heating element is provided with the continuous pad, and the other is provided with a plurality of dot pads. The area of ​​the dot pads is smaller than the area of ​​the continuous pads. Along the thickness direction of the circuit board, the projection of one continuous pad coincides with the projection of the plurality of dot pads, and one continuous pad and the plurality of dot pads are connected by solder.

15. The circuit board assembly according to claim 13, characterized in that, The continuous pads are elongated strip structures extending in a straight line, and at least two continuous pads are arranged in parallel, forming a strip-shaped non-filled area between two adjacent continuous pads.

16. The circuit board assembly according to any one of claims 1-15, characterized in that, The shape of the non-filled area is rectangular, triangular, circular, or polygonal.

17. The circuit board assembly according to any one of claims 1-16, characterized in that, The heating element is a chip.

18. An electronic device, characterized in that, Includes the circuit board assembly as described in any one of claims 1-17.

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