Backflow jig

Abstract

The utility model relates to the technical field of semiconductor manufacturing, and provides a backflow jig which comprises a backflow seat and a pressing assembly. And the downward pressing assembly is movably arranged on the backflow seat, the downward pressing assembly is provided with a downward pressing part, and the downward pressing assembly is used for enabling the downward pressing part to be pressed on the substrate through self weight. According to the configuration, in the backflow process of the substrate, local pressure is generated on the substrate through the downward pressing assembly, so that solder paste tends to diffuse towards the edge of the heat dissipation terminal in the backflow process of the substrate, and the phenomenon that after the substrate and the heat dissipation terminal are welded, holes exist in a solder layer is improved; the heat dissipation effect of the heat dissipation terminal can be improved, and the phenomenon that the internal stress at the welding position is large can be improved. In addition, the backflow jig can act on all the heat dissipation terminals and can be used for improving the welding flux cavity phenomenon of all the heat dissipation terminals on the substrate.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor manufacturing, in particular to a reflow fixture. Background Art

[0002] In semiconductor processing technology, it is usually necessary to set a heat dissipation terminal (pinfin) on a product (such as a substrate). The heat dissipation terminal is usually soldered on the substrate by reflow soldering.

[0003] Taking the substrate as an example, in the existing semiconductor secondary reflow process, after the substrate passes through the reflow furnace, there are usually voids in the solder layer under the substrate and the heat dissipation terminal, resulting in poor local heat dissipation. Moreover, the presence of voids can easily lead to greater stress in the solder, which in turn causes cracks in the substrate after the terminal is soldered.

[0004] The existing reflow fixture usually only plays the role of supporting or positioning the substrate, and it cannot effectively improve the phenomenon of solder voids.

[0005] To this end, the utility model provides a reflow fixture, which can improve the phenomenon of voids in the solder layer after the product and the heat dissipation terminal are welded, help improve the heat dissipation effect of the heat dissipation terminal and improve the phenomenon of large internal stress at the welding position. Utility Model Content

[0006] The utility model aims to provide a reflow fixture, which can improve the phenomenon of voids in the solder layer after the product and the heat dissipation terminal are welded, and is helpful to improve the heat dissipation effect of the heat dissipation terminal and improve the phenomenon of large internal stress at the welding position.

[0007] The utility model provides a reflux fixture, comprising: a reflux seat and a pressing component;

[0008] The pressing assembly is arranged on the reflow seat, and the pressing assembly has a pressing part, and the pressing assembly is used to press the pressing part on the product by its own weight.

[0009] Optionally, the pressing assembly includes a pressing rod, which is movably disposed on the reflux seat, and the first end of the pressing rod serves as the pressing portion.

[0010] Optionally, along the length direction of the pressure rod, approaching the end surface of the first end of the pressure rod, the cross-sectional area of ​​the pressing portion gradually decreases.

[0011] Optionally, the pressing assembly further includes a counterweight, and the counterweight is connected to the pressing rod.

[0012] Optionally, a through hole is provided on the reflux seat, and the pressure rod moves through the through hole along the opening direction of the through hole.

[0013] Optionally, at least two of the pressure rods are connected to one of the counterweights.

[0014] Optionally, the reflux seat includes a seat body and a mounting piece, the seat body is provided with a through slot, the mounting piece is arranged on the seat body and covers a part of the through slot, and the pressing assembly is arranged on the mounting piece.

[0015] Optionally, when a through hole is provided on the reflux seat, the through hole is opened in the mounting piece.

[0016] Optionally, the pressing down component is arranged opposite to the through slot, and the movement direction of the pressing down component relative to the reflux seat is consistent with the opening direction of the through slot.

[0017] Optionally, a groove is provided on the seat body, and the mounting member is built into the groove.

[0018] In summary, the reflow fixture includes: a reflow seat and a pressing component;

[0019] The pressing assembly is movably arranged on the reflow seat, and the pressing assembly has a pressing part, and the pressing assembly is used to press the pressing part on the product by its own weight.

[0020] With such configuration, when the product is in the reflow process, the pressing component generates local pressure on the product, so that the solder paste tends to diffuse to the edge of the heat dissipation terminal during the product reflow process, so as to improve the phenomenon of voids in the solder layer after the product and the heat dissipation terminal are soldered, which helps to improve the heat dissipation effect of the heat dissipation terminal and improve the phenomenon of large internal stress at the welding position. Moreover, the reflow fixture can act on all heat dissipation terminals and can be used to improve the solder void phenomenon of all heat dissipation terminals on the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a three-dimensional structural schematic diagram of a reflow fixture according to an embodiment of the utility model;

[0022] Figure 2 It is a schematic diagram of the top view of the reflow fixture of one embodiment of the utility model;

[0023] Figure 3 It is a side view structural schematic diagram of a reflow fixture according to an embodiment of the utility model;

[0024] Figure 4 It is a structural schematic diagram of a reflow fixture in use according to an embodiment of the utility model.

[0025] Among them, in the attached drawings:

[0026] 10-reflow seat; 11-seat body; 111-through groove; 112-groove; 113-process groove; 114-installation position; 12-installation piece; 121-through hole;

[0027] 20-downward pressure assembly; 201-downward pressure part; 21-pressure rod; 22-counterweight;

[0028] 30-stud;

[0029] 40- bottom plate;

[0030] 50-Substrate. DETAILED DESCRIPTION

[0031] The following is a further detailed description of the reflux fixture proposed by the utility model in combination with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the utility model will be clearer. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model.

[0032] As used in the present invention, the singular forms "one", "an", and "the" include plural objects, the term "or" is usually used to include the meaning of "and / or", the term "several" is usually used to include the meaning of "at least one", and the terms "at least two" or "a plurality" are usually used to include the meaning of "two or more". In addition, the terms "first", "second", and "third" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first", "second", and "third" may explicitly or implicitly include one or at least two of the features. In addition, as used in the present invention, "installed", "connected", "connected", and one element "set" on another element should be understood in a broad sense, usually only indicating that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the connection, coupling, cooperation or transmission between the two elements can be direct or indirect through an intermediate element, and cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, one element can be in any orientation such as inside, outside, above, below or one side of another element, unless the content clearly indicates otherwise. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. In addition, directional terms such as above, below, up, down, upward, downward, left, right, etc. are used relative to the exemplary embodiments as shown in the figures, with the upward or upper direction toward the top of the corresponding figure, and the downward or lower direction toward the bottom of the corresponding figure.

[0033] Please refer to Figure 1As shown, this embodiment provides a reflow fixture, which is used in conjunction with the soldering reflow of the product to improve the phenomenon of voids in the solder layer after the product and the heat dissipation terminal are soldered.

[0034] Please refer to Figure 1 As shown, the reflow fixture includes: a reflow seat 10 and a pressing component 20;

[0035] The pressing component 20 is movably arranged on the reflow seat 10, and the pressing component 20 has a pressing portion 201. The pressing component 20 is used to press the pressing portion 201 on the product by its own weight. The product refers to a semiconductor device with heat dissipation terminals welded thereto, such as a DBC substrate. In this embodiment, the product is described as a substrate.

[0036] During use, the placement posture of the reflow fixture should ensure that the pressing component 20 moves vertically relative to the reflow seat 10. Based on its own weight, the pressing component 20 can move vertically relative to the reflow seat 10 so that the pressing part 201 presses downward on the substrate.

[0037] like Figures 1 to 3 As shown, the reflow seat 10 is a plate-type structure as a whole. During normal use, the reflow seat 10 is placed horizontally, and the pressing component 20 is vertically slidably arranged on the reflow seat 10. The pressing component 20 will have a tendency to move vertically downward due to its own weight, so that the pressing part 201 is pressed downward on the substrate.

[0038] The pressing assembly 20 is provided to apply pressure to the substrate, rather than directly pressing the substrate through the reflow seat 10 , in order to accurately select the pressing position to avoid the circuit on the substrate.

[0039] Please continue to refer to Figure 1 As shown, in this embodiment, the reflow seat 10 includes a seat body 11 and a mounting member 12 .

[0040] The seat body 11 is a plate-type structure, and its overall outline is roughly rectangular. A through slot 111 is vertically opened on the seat body 11, the mounting member 12 is arranged on the seat body 11 and covers a part of the through slot 111, and the pressing assembly 20 is arranged on the mounting member 12.

[0041] Combination Figure 2As shown, the through slot 111 is a square slot, and the four sides of the through slot 111 are parallel to the four sides of the base 11, respectively. The through slot 111 is located in the middle of the base 11 along its width direction. The mounting member 12 is in the shape of a long strip, and the mounting member 12 extends along the length direction of the base 11. The mounting member 12 is located in the middle of the base 11 along its width direction, so the mounting member 12 is also located in the middle of the through slot 111 along the width direction of the base 11. The width dimension of the mounting member 12 is much smaller than the width dimension of the through slot 111 (in this embodiment, the width direction of the mounting member 12 and the width direction of the through slot 111 are consistent with the width direction of the base 11), so the mounting member 12 blocks a small part of the through slot 111, and the areas of the through slot 111 located on both sides of the width of the mounting member 12 are not blocked. The through groove 111 provides a field of view, making it easy to observe the pressing condition of the pressing component 20 through the through groove 111. At the same time, the through groove 111 also serves as a heat dissipation window, which is convenient for the heat dissipation of the substrate. Moreover, the through groove 111 also serves as a weight-reducing structure, which is conducive to the lightweight design of the reflow fixture.

[0042] In other alternative embodiments, the structure of the seat body 11 , the opening shape and setting position of the through slot 111 , and the setting method of the mounting member 12 can be adaptively adjusted based on actual use requirements.

[0043] Please continue to refer to Figure 1 As shown, in this embodiment, a groove 112 is provided on the seat body 11, and the groove 112 is provided on the upper surface of the seat body 11, and the setting position of the groove 112 matches the installation position of the mounting member 12. The groove 112 is divided by the through groove 111 to form a plurality of segmented structures. The groove 112 is adapted to the shape of the mounting member 12, and the mounting member 12 is conformably built into the groove 112, so that the upper surface of the mounting member 12 is flush with the upper surface of the seat body 11. In addition, the mounting member 12 is detachably mounted on the bottom of the groove 112 by screws. By setting the groove 112, the overall consistency of the seat body 11 and the mounting member 12 is better.

[0044] In this embodiment, the reflow seat 10 adopts a split structure consisting of a seat body 11 and a mounting member 12, and the mounting member 12 is detachably connected to the reflow seat 10 for easy replacement and later maintenance. In other alternative embodiments, the reflow seat 10 may also adopt an integrated structure. The specific structural form of the reflow seat 10 can be adaptively adjusted based on actual use requirements.

[0045] Please continue to refer to Figure 1 and Figure 2As shown, in this embodiment, the base body 11 is provided with a process groove 113, which is a strip-shaped groove. In this embodiment, six process grooves 113 are provided and are arranged on both sides of the through groove 111 along the width direction of the base body 11. The process groove 113 can be used as an avoidance hole or a weight reduction hole. In other alternative embodiments, the shape, position and number of the process grooves 113 can be adaptively adjusted based on the use requirements.

[0046] Please combine Figures 1 to 3 As shown, the pressing assembly 20 includes a pressing rod 21, and the pressing rod 21 is movably arranged on the reflux seat 10. Specifically, the pressing rod 21 is arranged on the mounting member 12, and the mounting member 12 is provided with a through hole 121, and the pressing rod 21 moves through the through hole 121 along the opening direction of the through hole 121. Since the mounting member 12 is detachably mounted on the seat body 11, and the pressing assembly 20 cooperates with the mounting member 12, the pressing assembly 20 of different specifications can be matched by replacing the mounting seat 12.

[0047] The first end ( Figure 3 The lower end of the pressing rod 21 is used as the pressing portion 201. Figure 3 The lower end surface of the middle pressure rod 21 is close to (i.e. along Figure 3 The cross-sectional area of ​​the pressing portion 201 gradually decreases, and the cross-sectional area here refers to the cross-sectional area formed by cutting perpendicular to the length direction of the pressing rod 21.

[0048] like Figure 1 and Figure 3 As shown, in this embodiment, the pressure rod 21 is a cylindrical rod, and the lower end of the pressure rod 21 is a truncated cone structure, so that the cross-sectional area of ​​the lower end surface of the pressure rod 21 is minimized to reduce the contact area between the pressure rod 21 and the substrate, thereby achieving a larger local downward force, and at the same time, it can also achieve effective avoidance of circuit components on the substrate.

[0049] The through hole 121 provided on the mounting member 12 is adapted to the shape of the pressure rod 21 and is set as a circular hole. The inner diameter of the through hole 121 is adapted to the outer diameter of the rod body of the pressure rod 21 to provide a better guiding effect for the pressure rod 21, thereby accurately limiting the movement direction of the pressure rod 21 relative to the return seat 10.

[0050] In other alternative embodiments, the pressing rod 21 can be configured as a square rod or other special-shaped rod structures. The pressing portion 201 can be configured as a conical structure such as a triangular pyramid, and the conical shape of the pressing portion 201 can be adaptively adjusted based on the cross-sectional shape of the pressing rod 21 .

[0051] To ensure sufficient downward pressure, the downward pressing assembly 20 in this embodiment further includes a counterweight 22 , and the counterweight 22 is connected to the pressing rod 21 .

[0052] Please refer to Figures 1 to 3 As shown, the counterweight 22 is a rectangular parallelepiped structure, which is connected to the upper end of the pressure rod 21. The pressure rod 21 can be connected to the counterweight 22 in a detachable manner, for example, the pressure rod 21 is detachably connected to the counterweight 22 through a universal joint such as a threaded joint or a clamping joint, so that the pressure rod 21 can adjust the downward force by replacing the counterweight 22 connected thereto, or the counterweight 22 can replace the pressure rod 21 connected thereto to adapt to different downward pressure scenarios.

[0053] In other alternative embodiments, the shape of the counterweight 22 and the connection method between the counterweight 22 and the pressure rod 21 can be adaptively adjusted based on actual use requirements. For example, the counterweight 22 can be set to a spherical shape, and the connection method between the counterweight 22 and the pressure rod 21 can be set to an integrally formed connection method.

[0054] Please continue to refer to Figures 1 to 3 As shown, in this embodiment, the two pressure rods 21 are connected to a counterweight 22. The two pressure rods 21 connected to the counterweight 22 are arranged along the length direction of the seat body 11, and the pressure rod 21 is connected to the middle position of the counterweight 22 along the width direction of the seat body 11, so as to ensure that the counterweight 22 provides a pure downward force for the two pressure rods 21, and prevent the pressure rod 21 from being stuck in the through hole 121 due to the offset torque caused by the offset of the counterweight 22.

[0055] In other alternative embodiments, one counterweight 22 can be connected to more pressure rods 21. In addition, the counterweight 22 can be connected to multiple pressure rods of the same specification, or can be connected to multiple pressure rods of different specifications to flexibly adapt to different usage scenarios.

[0056] Please refer to Figures 1 to 3 As shown, in this embodiment, the pressing assembly 20 is arranged opposite to the through slot 111. In the vertical projection, the counterweight 22 falls into the through slot 111 (as shown in FIG. Figure 2 As shown in the figure, the counterweight 22 is smaller than the through slot 111 to prevent the counterweight 22 from blocking the through slot 111. The through hole 121 is arranged opposite to the through slot 111, so that the movement direction of the pressing assembly 20 relative to the reflow seat 10 is consistent with the opening direction of the through slot 111 (both are vertical directions). After the pressing rod 21 passes through the through hole 121, it will pass through the through slot 111 and press down the substrate located below the reflow seat 10.

[0057] Please refer to Figures 1 to 3As shown, in this embodiment, three through slots 111 are provided on the seat body 11, and the three through slots 111 are arranged along the length direction of the seat body 11, and the mounting member 12 is arranged opposite to the three through slots 111. In addition, the reflow fixture includes three pressing components 20, and the three pressing components 20 correspond to the three through slots 111 one by one. Correspondingly, three groups of through holes 121 are provided on the mounting member 12, and each group includes two through holes 121 for two pressing rods 21 of the pressing component 20 to pass through. Through the configuration of multiple through slots 111 and multiple pressing components 20, the reflow fixture can be used with multiple substrates at the same time.

[0058] In this embodiment, three pressing components 20 and three through slots 111 are provided. In other alternative embodiments, the number of pressing components 20 and through slots 111 can be adaptively adjusted based on actual use requirements.

[0059] In this embodiment, one pressing assembly 20 corresponds to one through slot 111. In other alternative embodiments, one pressing assembly 20 may match with a plurality of through slots 111, or one through slot 111 may match with a plurality of pressing assemblies 20.

[0060] Please refer to Figures 1 to 3 As shown, in this embodiment, five installation positions 114 are arranged at the four corners of the seat body 11 and near one long side thereof. The specific arrangement position and number of the installation positions 114 can be adjusted based on actual use requirements.

[0061] Each mounting position is connected to a stud 30, and a nut and a washer are connected to the stud 30. Figure 4 As shown, when the reflow fixture is in use, the stud 30 is connected to the bottom plate 40, and the bottom plate 40 is located below the seat 11. There is a gap between the bottom plate 40 and the seat 11. At this time, the bottom plate 40 can be used as the base of the reflow fixture, and the reflow seat 10 is used as the upper cover of the reflow fixture. A substrate 50 is placed on the bottom plate 40, wherein the side of the substrate 50 connected to the heat dissipation terminal is supported downward on the bottom plate 40, and the lower pressing part 201 of the pressing rod 21 (i.e., the lower end of the pressing rod 21) is pressed on the other side of the substrate 50, and the substrate and the heat dissipation terminal are pressed tightly by the downward pressure.

[0062] When the substrate is in the reflow process, the pressing component 20 generates local pressure on the substrate, so that the solder paste tends to diffuse to the edge of the heat dissipation terminal during the substrate reflow process, so as to improve the phenomenon of voids in the solder layer after the substrate and the heat dissipation terminal are soldered, which helps to improve the heat dissipation effect of the heat dissipation terminal and improve the phenomenon of large internal stress at the welding position. Moreover, the reflow fixture can act on all heat dissipation terminals and can be used to improve the solder void phenomenon of all heat dissipation terminals on the substrate.

[0063] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0064] The above description is only a description of the preferred embodiment of the utility model, and is not any limitation on the scope of the utility model. Any changes and modifications made by ordinary technicians in the field of the utility model based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A reflow fixture, characterized in that: include: Reflux seat and hold-down assembly; The pressing assembly is arranged on the reflow seat, and the pressing assembly has a pressing part, and the pressing assembly is used to press the pressing part on the product by its own weight; The pressing assembly comprises a pressing rod, which is movably arranged on the reflux seat, and the first end of the pressing rod serves as the pressing portion; The reflux seat comprises a seat body and a mounting piece, the seat body is provided with a through slot, the mounting piece is arranged on the seat body and covers a part of the through slot, and the pressing assembly is arranged on the mounting piece.

2. The reflow fixture according to claim 1, characterized in that: Along the length direction of the pressing rod, the cross-sectional area of ​​the pressing portion gradually decreases toward the end surface of the first end of the pressing rod.

3. The reflow fixture according to claim 1, characterized in that: The pressing assembly further includes a counterweight, which is connected to the pressing rod.

4. The reflow fixture according to claim 1, characterized in that: The reflux seat is provided with a through hole, and the pressure rod moves along the opening direction of the through hole and passes through the through hole.

5. The reflow fixture according to claim 3, characterized in that: At least two of the pressure rods are connected to one of the counterweights.

6. The reflow fixture according to claim 4, characterized in that: The through hole is formed in the mounting member.

7. The reflow fixture according to claim 1, characterized in that: The pressing down component is arranged opposite to the through slot, and the movement direction of the pressing down component relative to the reflux seat is consistent with the opening direction of the through slot.

8. The reflow fixture according to claim 1, characterized in that: The seat body is provided with a groove, and the mounting piece is built in the groove.

Images