Lead frame and connection structure

Abstract

The utility model relates to a lead frame and a connection structure. The lead frame comprises a frame body and a protruding part. The protruding part is arranged on one side of the frame body and used for being connected with a connected piece. According to the lead frame, the reliability of connection between the lead frame and the connected piece can be improved, and the performance and reliability of the semiconductor power device can be improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor packaging technology, and in particular to a lead frame and a connection structure. Background Art

[0002] With the development of power semiconductors, the requirements for packaging technology are increasing. Currently, in power semiconductor device packaging, solder tabs are usually used to connect the chip or substrate to the lead frame.

[0003] To ensure a consistent height of the solder layer, related technologies typically employ a soldering tab with a metal mesh or metal strip for height control. Specifically, the soldering tab with a metal mesh or metal strip is positioned between the chip or substrate and the lead frame. The chip or substrate, the soldering tab, and the lead frame are then soldered together to achieve a connection between the chip or substrate and the lead frame.

[0004] However, during the high-temperature melting process of the solder sheet, the solder sheet will be converted into a molten liquid, and the metal mesh or metal strip will shift relative to the original position of the solder sheet, causing the metal mesh or metal strip to shift to other areas of the chip or substrate, thereby causing failure of the chip or substrate and leading to failure of the semiconductor power device. Utility Model Content

[0005] Based on this, it is necessary to provide a lead frame and connection structure to solve the problem that the metal mesh or metal strip will shift relative to the original position of the solder piece during the high-temperature melting process, causing the chip or substrate to fail.

[0006] A lead frame, comprising:

[0007] Framework body;

[0008] The protrusion is arranged on one side of the frame body and is used to connect with the connected component.

[0009] In one embodiment, the frame body includes a first surface and a second surface disposed opposite to each other; the protrusion is disposed on the first surface;

[0010] The lead frame further includes a recessed portion, which is arranged on the second surface of the frame body and recessed toward the first surface to form a protruding portion.

[0011] In one embodiment, the protrusion is bent at one side of the frame body;

[0012] Alternatively, the protrusion is bonded to one side of the frame body.

[0013] In one embodiment, the lead frame further comprises:

[0014] The covering portion covers the surface of the protruding portion.

[0015] In one embodiment, the frame body comprises:

[0016] a first connecting portion;

[0017] a second connecting portion, wherein the protrusion is provided on one side of at least one of the first connecting portion and the second connecting portion;

[0018] A bending portion, the bending portion comprising a first bending unit, a second bending unit, and a third bending unit, the second bending unit being connected to the first bending unit and the third bending unit, a side of the first bending unit away from the second bending unit being connected to the first connecting portion, and a side of the third bending unit away from the second bending unit being connected to the second connecting portion;

[0019] The two sides of the first bending unit intersect with the first connecting portion and the second bending unit respectively, and the two sides of the third bending unit intersect with the second connecting portion and the second bending unit respectively.

[0020] In one embodiment, along the protruding direction of the protruding portion, the projection of the protruding portion has a shape selected from the group consisting of a rectangle, a circle, a polygon, and an irregular shape.

[0021] In one embodiment, the number of the protrusion is at least one.

[0022] In one embodiment, the dimension of the protrusion along the protruding direction is less than or equal to the thickness of the frame body;

[0023] Alternatively, a dimension of the protruding portion along the protruding direction is greater than a thickness of the frame body.

[0024] In one embodiment, the lead frame is an integrally formed structure.

[0025] A connection structure comprises a welding portion and a lead frame. The welding portion is arranged on a side of a protruding portion away from a frame body and is used for connecting the protruding portion and a connected component.

[0026] The lead frame includes a frame body and a protrusion. The protrusion is provided on one side of the frame body, and the protrusion is used to connect to the connected part. The lead frame of the present application, by providing the protrusion on one side of the frame body, can prevent the protrusion from moving relative to the frame body along the molten solder tab during the high-temperature melting of the solder tab when the protrusion and the connected part are connected by soldering. The protrusion and the frame body can always be a whole, and the lead frame and the connected part can have a high degree of matching, thereby improving the reliability of the connection between the lead frame and the connected part, and further improving the performance and reliability of the semiconductor power device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1Schematic diagram of the structure of a lead frame in one embodiment of the present application.

[0028] Figure 2 This is a structural schematic diagram of a lead frame in an embodiment of the present application from another perspective.

[0029] Figure 3 Schematic diagram of the structure of the connection between the lead frame and the connected component in one embodiment of the present application.

[0030] Figure 4 for Figure 2 A local enlarged schematic diagram of point A in the middle.

[0031] Figure 5 Schematic diagram of another structure of a lead frame in an embodiment of the present application.

[0032] Description of reference numerals:

[0033] 1. Lead frame; 2. Connection structure; 3. Connected parts;

[0034] 11. Frame body; 12. Protruding portion; 13. Recessed portion;

[0035] 111. First connecting portion; 112. Second connecting portion; 113. Bend portion;

[0036] 1131. First bending unit; 1132. Second bending unit; 1133. Third bending unit. DETAILED DESCRIPTION

[0037] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0038] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0039] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0040] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0041] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0042] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0043] First of all, it should be noted that the lead frame, as the chip carrier of the integrated circuit, is a key structural component that uses bonding materials (gold, aluminum, copper) to achieve electrical connection between the internal circuit lead ends of the chip and the external leads to form an electrical circuit. It acts as a bridge connecting to external wires. Lead frames are required in most semiconductor integrated blocks and are an important basic material in the electronic information industry.

[0044] Furthermore, copper alloys for lead frames are broadly categorized into copper-iron, copper-nickel-silicon, copper-chromium, and copper-nickel-tin. Ternary and quaternary copper alloys offer superior performance and lower costs compared to traditional binary alloys. Copper-iron alloys are the most widely available and offer excellent mechanical strength, stress relaxation resistance, and low creep properties, making them an excellent material for lead frames. Due to the demands of lead frame manufacturing and packaging applications, in addition to high strength and thermal conductivity, the material also requires excellent brazing, processability, etching, and oxide film adhesion properties. The trend toward high strength, high conductivity, and low cost is driving the development of materials. By adding small amounts of various elements to copper, the alloy's strength (resisting deformation) and overall performance are enhanced without significantly reducing conductivity.

[0045] In addition, it should be noted that the connected part in this application is a structure connected to the lead frame. Exemplarily, the lead frame is a chip or other substrate. Of course, the connected part can also be other structures connected to the lead frame. For the sake of convenience, the chip is used as an example to refer to the connected part in this application. In addition, it should be noted that the lead frame and chip in this application are both part of the structure of the semiconductor power device, that is, the connection state between the lead frame and the chip directly affects the performance and reliability of the semiconductor power device.

[0046] See Figure 1 、 Figure 2 and Figure 3 As shown, a lead frame 1 provided in an embodiment of the present application includes a frame body 11 and a protruding portion 12. The protruding portion 12 is provided on one side of the frame body 11 and is used to connect to the connected component 3.

[0047] Specifically, the frame body 11 serves as the main structure of the lead frame 1, part of the area serves as the functional area of ​​the lead frame 1, and is used to connect with the chip to realize the corresponding function, and part of the area serves as the supporting structure of the lead frame 1, and is used to cooperate with other structures in the semiconductor power device.

[0048] Furthermore, the frame body 11 is usually connected to the chip by welding, and when the frame body 11 and the chip are welded, the height between the frame body 11 and the chip needs to be controlled. Figure 2 、 Figure 3 and Figure 4 As shown, since the protrusion 12 is provided on one side of the frame body 11 , the protrusion 12 is used to connect with the chip, so that the height between the frame body 11 and the chip can be controlled by the protrusion 12 .

[0049] Because protrusion 12 is provided on one side of frame body 11 and is used to connect to the chip, i.e., after the lead frame 1 is connected to the chip, protrusion 12 is provided between frame body 11 and the chip. Thus, the height of protrusion 12 itself can control the thickness of the solder layer during the soldering process. Furthermore, it can be understood that protrusion 12 is provided on one side of frame body 11, so that protrusion 12 and frame body 11 always form a unified whole. During the soldering process between protrusion 12 and the chip using a soldering tab, the soldering tab may melt due to the high temperature. Since protrusion 12 and frame body 11 always form a unified whole, the position of protrusion 12 relative to frame body 11 remains unchanged during the melting process. This ensures that protrusion 12 does not shift relative to frame body 11, thereby preventing chip failure caused by protrusion 12 shifting. This improves the yield rate of the connection between lead frame 1 and chip, thereby improving the performance and reliability of semiconductor power devices.

[0050] In addition, it should be noted that if a welding piece with a metal mesh or metal strip is used to weld the frame body 11 and the chip, a large amount of copper mesh filling process needs to be added to the normal welding piece manufacturing process. At the same time, the welding piece with a metal mesh or metal strip finally needs to undergo a cutting process, and an inevitable irregular burr surface will be formed during the cutting process. The burr structure will also cause damage to the surface of the chip during use, affecting the normal use of the chip.

[0051] Thus, with the lead frame 1 of the present application, since the protrusion 12 is provided on one side of the frame body 11, the protrusion 12 and the frame body 11 always form a unified whole, thereby enabling the use of ordinary solder tabs without metal mesh or metal strips. On the one hand, the protrusion 12 and the chip can be directly connected via the solder tabs, thereby achieving a connection between the lead frame 1 and the chip, which can reduce the increased process difficulty caused by the use of complex solder tabs, thereby simplifying the process and facilitating the operator's operation. On the other hand, since the processing and preparation difficulty of the solder tabs are simplified, production costs can be reduced and production efficiency can be improved.

[0052] It is understandable that the connection structure between the protrusion 12 and the chip is not limited to welding pieces such as metal mesh or metal strips. It is only explained here as an example. Printed solder or other connection methods can also be used between the protrusion 12 and the chip. The connection method between the protrusion 12 and the chip is not limited here.

[0053] In one embodiment, see Figure 1 and Figure 2As shown, the frame body 11 includes a first surface and a second surface arranged opposite to each other; the protrusion 12 is provided on the first surface; the lead frame 1 also includes a recessed portion 13, which is provided on the second surface of the frame body 11 and recessed toward the first surface to form the protrusion 12.

[0054] In this way, a recess 13 can be provided on one side of the frame body 11, and a protrusion 12 can be formed through the recess 13. Specifically, the lead frame 1 of this embodiment forms a recess 13 on one side of the frame body 11 by stamping, and forms a protrusion 12 on the other side of the frame body 11 by the recess 13. On the one hand, the lead frame 1 forms the protrusion 12 by stamping, and the stamping operation is simple and easy to operate, thereby reducing the difficulty of the operator's operation and improving work efficiency. On the other hand, since the recess 13 and the protrusion 12 are respectively formed on both sides of the frame body 11 through the stamping process, the material cost of the protrusion 12 is part of the frame body 11, and there is no need to add additional material cost for the protrusion 12, thereby reducing the cost of the lead frame 1 during production.

[0055] In addition, due to the stamping process, the protrusion 12 and the frame body 11 are always a unified whole. Therefore, during the melting process of the solder sheet, the position of the protrusion 12 relative to the frame body 11 will not change, thereby ensuring that the protrusion 12 will not shift relative to the frame body 11, thereby avoiding the failure of the chip caused by the shift of the protrusion 12, thereby improving the yield of the connection between the lead frame 1 and the chip, and further improving the performance and reliability of the semiconductor power device.

[0056] Of course, it can be understood that the above embodiment in the present application is only one of the implementation methods of the present application. The formation of the protrusion 12 in the present application is not limited to the stamping process. Furthermore, the protrusion 12 of the present application does not necessarily need to be formed by the recessed portion 13 during the formation process. The specific formation process of the protrusion 12 will not be repeated here.

[0057] In one embodiment, see Figure 5 As shown, the protrusion 12 is bent at one side of the frame body 11 ; or, the protrusion 12 is adhered to one side of the frame body 11 .

[0058] In this way, the present application can bend a portion of the frame body 11 to form a protrusion 12 in the bent portion, thereby controlling the height between the frame body 11 and the chip. In addition, the present application can externally process the protrusion 12 and bond the protrusion 12 to the frame body 11, thereby also controlling the height between the frame body 11 and the chip, simplifying the connection between the protrusion 12 and the frame body 11, and facilitating the processing of the lead frame 1.

[0059] The present application can make corresponding changes to the processing technology of the protrusion 12 according to actual processing requirements, and the specific processing technology of the protrusion 12 will not be described in detail here.

[0060] In one embodiment, the lead frame 1 further includes a covering portion that covers the surface of the protruding portion 12 .

[0061] Because the materials of lead frame 1 and chip differ, directly soldering them together using solder tabs would compromise the bonding effect. However, by providing a covering portion on the surface of protrusion 12, made of the same or similar material as the chip, the covering portion enhances the bonding effect between protrusion 12 and chip, further strengthening the bonding strength between lead frame 1 and chip, thereby improving the reliability and lifespan of the overall structure.

[0062] Of course, it can be understood that the above embodiment in the present application is only one implementation method of the present application, and the covering part in the present application is also an optional implementation method of the present application, and the covering part will not be described in detail here.

[0063] In one embodiment, see Figure 5 As shown, the frame body 11 includes a first connecting portion 111, a second connecting portion 112, and a bent portion 113. The protruding portion 12 is provided on one side of at least one of the first connecting portion 111 and the second connecting portion 112; the bent portion 113 includes a first bending unit 1131, a second bending unit 1132, and a third bending unit 1133. The second bending unit 1132 is connected to the first bending unit 1131 and the third bending unit 1133. The side of the first bending unit 1131 away from the second bending unit 1132 is connected to the first connecting portion 111, and the side of the third bending unit 1133 away from the second bending unit 1132 is connected to the second connecting portion 112. The two sides of the first bending unit 1131 intersect with the first connecting portion 111 and the second bending unit 1132 respectively, and the two sides of the third bending unit 1133 intersect with the second connecting portion 112 and the second bending unit 1132 respectively.

[0064] It can be understood that since the two sides of the first bending unit 1131 intersect with the first connecting portion 111 and the second bending unit 1132 respectively, and the two sides of the third bending unit 1133 intersect with the second connecting portion 112 and the second bending unit 1132 respectively, the shape of the frame body 11 is a "J" shape.

[0065] In this way, the first connection portion 111 and the second connection portion 112 can be used to connect the lead frame 1 to different parts of the chip, thereby improving the reliability of the connection between the lead frame 1 and the chip. In addition, the bent portion 113 can be used to connect to other components of the semiconductor power device, so that the bent portion 113 and the first connection portion 111 and the second connection portion 112 can each play different roles, avoiding interference between the bent portion 113 and the first connection portion 111 and the second connection portion 112, thereby improving the performance of the semiconductor power device.

[0066] In one embodiment, along the protruding direction of the protruding portion 12 , the projection of the protruding portion 12 has a shape selected from the group consisting of a rectangle, a circle, a polygon, and an irregular shape.

[0067] In this way, the shape of the protrusion can be customized according to actual needs, so that the best design shape can be selected according to the size of the chip and the welding effect, thereby achieving process optimization.

[0068] In one embodiment, the number of the protrusion 12 is at least one.

[0069] Optionally, there is one protrusion 12 , which is located at the center of gravity of the frame body 11 ; or, there are multiple protrusions 12 , which are evenly distributed along the surface of one side of the frame body 11 .

[0070] In this way, the number of bumps can be customized according to actual needs, so that the optimal design number can be selected according to the size of the chip and the welding effect, thereby achieving process optimization.

[0071] In addition, since the number of the protrusions 12 is one or more, the lead frame 1 can be diversified and applicable to different application scenarios.

[0072] Of course, the position of the protrusion 12 relative to the frame body 11 is not restrictive. The center of gravity and uniform arrangement are only used as examples for explanation. The present application can reasonably set the position of the protrusion 12 according to actual processing requirements.

[0073] In one embodiment, the dimension of the protruding portion 12 along the protruding direction is less than or equal to the thickness of the frame body 11 .

[0074] In this way, during the process of preparing the protrusion 12 by stamping or other methods, the protrusion 12 can be prevented from being too large in the protruding direction, which could cause damage to the protrusion 12. Furthermore, because the protrusion 12 in the protruding direction is less than or equal to the thickness of the frame body 11, the structural integrity of the protrusion 12 can be ensured. This improves the yield of the connection between the lead frame 1 and the chip after the solder tab connects the protrusion 12 to the chip, thereby improving the performance and reliability of the semiconductor power device.

[0075] In one embodiment, the dimension of the protruding portion 12 along the protruding direction is greater than the thickness of the frame body 11 .

[0076] In this way, when the protrusion 12 is processed by bending, bonding or other processes, the height between the frame body 11 and the chip can be increased by making the size of the protrusion 12 along the protruding direction larger than the thickness of the frame body 11, thereby achieving control of the height between the frame body 11 and the chip.

[0077] In one embodiment, the lead frame 1 is an integrally formed structure.

[0078] In this way, it can be ensured that the lead frame 1 is always a unified whole, so that during the melting process of the solder piece, the position of the protrusion 12 relative to the frame body 11 will not change, thereby ensuring that the protrusion 12 will not shift relative to the frame body 11, thereby avoiding the failure of the chip caused by the shift of the protrusion 12, thereby improving the yield of the connection between the lead frame 1 and the chip, and further improving the performance and reliability of the semiconductor power device.

[0079] In addition, since the lead frame 1 is an integrally formed structure, the preparation process of the lead frame 1 can be simplified, the operation of the operator can be facilitated, and the production efficiency of the lead frame 1 can be improved.

[0080] The connection structure 2 provided in one embodiment of the present application, see Figure 3 As shown, the connection structure 2 includes a welding portion and a lead frame 1 . The welding portion is provided on a side of the protruding portion 12 away from the frame body 11 and is used to connect the protruding portion 12 and the connected component 3 .

[0081] It should be noted that the welding part in this application is the structure connecting the lead frame 1 and the chip. This application uses the welding piece to exemplarily refer to the welding part. Of course, the welding part can also be other structures. Here, the specific structure of the welding part is not repeated.

[0082] Because the solder tab is disposed on the side of the protrusion 12 facing away from the frame body 11 and is used to connect the protrusion 12 to the connected component 3, on the one hand, the protrusion 12 and the chip can be directly connected via the solder tab, thereby achieving a connection between the lead frame 1 and the chip. This can reduce the increased process difficulty caused by the use of complex solder tabs, thereby simplifying the process and facilitating the operator's operation. On the other hand, since the processing and preparation difficulty of the solder tab are simplified, production costs can be reduced and production efficiency can be improved.

[0083] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A lead frame, characterized in that: include: Framework body; The protrusion is provided on one side of the frame body and is used to connect with the connected component.

2. The lead frame according to claim 1, wherein: The frame body includes a first surface and a second surface that are opposite to each other; the protrusion is provided on the first surface; The lead frame further includes a recessed portion, which is provided on the second surface of the frame body and recessed toward the first surface to form the protruding portion.

3. The lead frame according to claim 1, wherein: The protrusion is bent at one side of the frame body; Alternatively, the protrusion is bonded to one side of the frame body.

4. The lead frame according to claim 1, wherein The lead frame further includes: The covering portion covers the surface of the protruding portion.

5. The lead frame according to claim 1, wherein The frame body comprises: a first connecting portion; a second connecting portion, wherein the protrusion is provided on one side of at least one of the first connecting portion and the second connecting portion; a bending portion, the bending portion comprising a first bending unit, a second bending unit, and a third bending unit, the second bending unit being connected to the first bending unit and the third bending unit, a side of the first bending unit away from the second bending unit being connected to the first connecting portion, and a side of the third bending unit away from the second bending unit being connected to the second connecting portion; Wherein, two sides of the first bending unit intersect with the first connecting portion and the second bending unit respectively, and two sides of the third bending unit intersect with the second connecting portion and the second bending unit respectively.

6. The lead frame according to any one of claims 1 to 5, characterized in that: Along the protruding direction of the protruding portion, a projection of the protruding portion has a shape that is one of a rectangle, a circle, a polygon, and an irregular shape.

7. The lead frame according to any one of claims 1 to 5, wherein: The number of the protrusion is at least one.

8. The lead frame according to any one of claims 1 to 5, wherein: The dimension of the protruding portion along the protruding direction is less than or equal to the thickness of the frame body; Alternatively, a dimension of the protruding portion along a protruding direction is greater than a thickness of the frame body.

9. The lead frame according to any one of claims 1 to 5, wherein: The lead frame is an integrally formed structure.

10. A connection structure, characterized in that: The lead frame comprises a welding portion and the lead frame according to any one of claims 1 to 9, wherein the welding portion is provided on a side of the protruding portion away from the frame body and is used to connect the protruding portion and the connected member.

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