Lead frame structure, method of manufacturing the same, package structure, chip assembly, terminal

Abstract

The embodiment of the present application provides a lead frame structure, a preparation method thereof, a packaging structure, a chip assembly and a terminal. The lead frame structure comprises a lead frame and a connecting rib. The connecting rib is connected to the outer periphery of the lead frame. The connecting rib comprises a first connecting rib and a second connecting rib. The first connecting rib and the second connecting rib are connected to each other. A first groove is arranged at the intersection of the first connecting rib and the second connecting rib. The first groove extends from the intersection to the first connecting rib and / or the first groove extends from the intersection to the second connecting rib. The lead frame structure can reduce the shearing force required for cutting the lead frame structure, improve the cutting efficiency and prolong the service life of the cutting knife.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging technology, and in particular to a lead frame structure and its preparation method, packaging structure, chip assembly, and terminal. Background Technology

[0002] As a chip carrier for integrated circuits, the leadframe is a key structural component that uses bonding materials (gold wire, aluminum wire, copper wire) to electrically connect the internal circuit leads of the chip to the external leads, forming an electrical circuit. It acts as a bridge connecting the chip and external wires. However, in existing technologies, when cutting the leadframe structure into multiple leadframes, the thickness of the area to be cut is relatively large, requiring the cutter to provide a large shearing force. This not only affects cutting efficiency but also easily causes wear on the cutter, reducing its service life. Summary of the Invention

[0003] This invention discloses a lead frame structure, its preparation method, packaging structure, chip assembly, and terminal, which can reduce the shearing force required for cutting the lead frame structure, improve cutting efficiency, and extend the service life of the cutter.

[0004] To achieve the above objectives, in a first aspect, the present invention discloses a lead frame structure, comprising:

[0005] Lead frame; and

[0006] A connecting rib is connected to the outer periphery of the lead frame. The connecting rib includes a first connecting rib and a second connecting rib. The first connecting rib and the second connecting rib intersect and are connected. A first groove is provided at the intersection of the first connecting rib and the second connecting rib. The first groove extends from the intersection to the first connecting rib, and / or the first groove extends from the intersection to the second connecting rib.

[0007] By providing a first groove at the intersection of the first connecting rib and the second connecting rib, and extending the first groove to at least one of the first connecting rib or the second connecting rib, that is, extending the first groove to the cutting position of the first connecting rib or the second connecting rib, the thickness of the lead frame structure at the cutting position is reduced. This not only reduces the shearing force required by the cutter and improves the cutting efficiency, but also reduces the wear of the cutter and extends its service life.

[0008] As an optional implementation, in an embodiment of the first aspect of the present invention, there are multiple lead frames arranged sequentially in the same direction. A first connecting rib is provided between two adjacent lead frames, and each first connecting rib intersects and connects with a second connecting rib to form an intersection. A first groove at each intersection communicates with the corresponding two adjacent lead frames; or

[0009] The lead frame is a plurality of such lead frames, which are arranged in an array. A first connecting rib or a second connecting rib is provided between two adjacent lead frames to form an intersection at the middle of four adjacent lead frames. The first groove at each intersection is connected to the corresponding four adjacent lead frames.

[0010] By connecting the first groove to two or four adjacent lead frames, the high-temperature liquid molding compound can flow between different lead frames during the packaging process, which helps to make the molding compound uniform at each lead frame and improve the reliability of the chip assembly.

[0011] As an optional implementation, in an embodiment of the first aspect of the present invention, the first connecting rib includes a first part and a second part that are connected to each other, the second connecting rib includes a third part and a fourth part that are connected to each other, the third part intersects and is connected to the first part, and the first groove is provided at the intersection of the third part and the first part.

[0012] The first portion has opposing first and second sides, the first side facing the lead frame, and the first side and / or the second side having a second groove communicating with the first groove; and / or,

[0013] The third part has opposing third and fourth sides, the third side facing the lead frame, and the third side and / or the fourth side is provided with a third groove, the third groove communicating with the first groove.

[0014] Based on the first groove connecting the adjacent lead frame, a second groove is provided in the first part of the first connecting rib, and / or a third groove is provided in the third part of the second connecting rib. This is beneficial to increase the opening size of the connection port of the adjacent lead frame, which facilitates the flow of the molding compound.

[0015] As an optional implementation, in an embodiment of the first aspect of the invention, the first portion further has a fifth side surface connected to the first side surface and the second side surface, the fifth side surface being connected to the groove wall surface of the first groove, and the second groove having a first opening located on the fifth side surface; and / or,

[0016] The third part also has a sixth side connected to the third side and the fourth side, the sixth side being connected to the groove wall of the first groove, and the third groove having a second opening located on the sixth side.

[0017] The second groove extends toward the fifth side and forms a first opening on the fifth side, and / or the third groove extends toward the sixth side and forms a second opening on the sixth side, which can maximize the connection between adjacent lead frames and allow more molding compound to flow.

[0018] As an optional implementation, in an embodiment of the first aspect of the invention, the first connecting rib has a first surface and a second surface opposite each other along a first direction, the first surface being disposed toward the lead frame, and the width of the first connecting rib being uniform along the second direction in the first direction; and / or,

[0019] The second connecting rib has a third and a fourth face opposite each other along a second direction, the third face being disposed toward the lead frame, and the width of the second connecting rib is consistent along the first direction in the second direction;

[0020] The second direction is perpendicular to the first direction.

[0021] The width of the first connecting rib is kept consistent at all points along the second direction, and / or the width of the second connecting rib is kept consistent at all points along the first direction, so as to retain as much material of the substrate as possible when the substrate is etched to form the first and second connecting ribs. This allows the first and second connecting ribs to be cut off and recycled after the encapsulation is completed, and to be re-formed into the substrate to make the lead frame structure, thereby reducing production costs.

[0022] As an optional implementation, in an embodiment of the first aspect of the present invention, in a third direction, the depth of the first groove is equal to 1 / 3 to 2 / 3 of the thickness of the second connecting rib, and the third direction is perpendicular to the plane in which the first connecting rib and the second connecting rib are located.

[0023] By controlling the depth of the first groove within a certain range, it is possible to avoid situations where the depth of the first groove is too large, affecting the strength of the lead frame structure, or the depth of the first groove is too small, making it impossible to reduce the shearing force of the cutter to a lower range. This achieves a balance between ensuring the overall strength of the lead frame structure and reducing the shearing force required by the cutter.

[0024] Secondly, embodiments of the present invention provide a method for preparing a lead frame structure as described in the first aspect above, the method comprising the following steps:

[0025] A substrate is provided, and a photosensitive film is disposed on the surface of the substrate;

[0026] The photosensitive film is exposed to form a first patterned area and a second patterned area on the substrate;

[0027] The substrate is subjected to development and etching processes to form the lead frame, the first connecting rib, and the second connecting rib in the first patterned area, and to form the first groove in the second patterned area.

[0028] This preparation method can produce the aforementioned lead frame structure, which is beneficial to improve cutting efficiency, thereby increasing the production efficiency of the lead frame, and can also reduce cutter wear and extend the cutter's service life.

[0029] Thirdly, embodiments of the present invention provide a packaging structure, which includes a chip, leads, and a lead frame structure as described in the first aspect above. The chip is disposed on a base island of the lead frame, and the leads connect the chip and the pins of the lead frame. Because this packaging structure includes the aforementioned lead frame structure, when it is cut into chip assemblies, it helps to reduce the shearing force required by the cutter, thereby improving cutting efficiency and thus increasing the production efficiency of chip assemblies. Furthermore, it can reduce cutter wear, extend cutter life, and reduce the manufacturing cost of chip assemblies.

[0030] Fourthly, embodiments of the present invention provide a chip assembly, which is manufactured by cutting the packaging structure described in the third aspect. During the production process of this chip assembly, it is advantageous to reduce the shearing force required by the cutter, thereby improving cutting efficiency and thus increasing the production efficiency of the chip assembly. Furthermore, it can reduce cutter wear, extend cutter lifespan, and reduce the manufacturing cost of the chip assembly.

[0031] Fifthly, embodiments of the present invention provide a terminal, the terminal including a circuit board and the chip assembly described in the fourth aspect, the chip assembly being electrically connected to the circuit board. In the production process of this terminal, it is beneficial to reduce the shearing force required by the cutter, thereby improving cutting efficiency and thus increasing the production efficiency of the terminal. Furthermore, it can reduce cutter wear, extend the cutter's service life, and reduce the manufacturing cost of the terminal.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] This invention provides a lead frame structure, its fabrication method, packaging structure, chip assembly, and terminal. By providing a first groove at the intersection of a first connecting rib and a second connecting rib on the outer periphery of the lead frame, and extending the first groove from the intersection to the first connecting rib, and / or extending the first groove from the intersection to the second connecting rib, the first groove is located at the cutting position of the lead frame structure. Since the thickness of the lead frame structure at the first groove is less than the thickness of the first and second connecting ribs, when the lead frame structure needs to be cut into several lead frames, a cutter can cut the position of the lead frame structure with the first groove, reducing the thickness at the cutting position, reducing cutter wear, increasing cutter lifespan, and simultaneously improving cutting efficiency. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of a lead frame structure provided in an embodiment of the present invention;

[0036] Figure 2 yes Figure 1 Enlarged view of point A;

[0037] Figure 3 yes Figure 2 A three-dimensional diagram of the lead frame structure in the image;

[0038] Figure 4 yes Figure 2 A cross-sectional view of the lead frame structure along the BB direction;

[0039] Figure 5 This is a schematic diagram of another lead frame structure provided in an embodiment of the present invention;

[0040] Figure 6 yes Figure 5 Enlarged view of point C;

[0041] Figure 7 yes Figure 6 A cross-sectional view of the lead frame structure along the DD direction;

[0042] Figure 8 This is a schematic diagram of another lead frame structure provided in an embodiment of the present invention;

[0043] Figure 9 yes Figure 8 Enlarged view of point E;

[0044] Figure 10 yes Figure 9 A three-dimensional diagram of the lead frame structure in the image;

[0045] Figure 11 yes Figure 9 A cross-sectional view of the lead frame structure along the FF direction;

[0046] Figure 12 This is a flowchart of a method for preparing a lead frame structure provided in an embodiment of the present invention. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0049] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0050] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0051] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0052] Before explaining the technical solution of this application, the application scenarios involved in the embodiments of this application will be explained first.

[0053] When manufacturing chip components, it is usually necessary to first process the lead frame structure, then fix the chip on the base island of each lead frame in the lead frame structure, connect the chip to the pin using leads, then put the chip and lead frame structure into a mold, inject molding compound, bake and harden the molding encapsulation, and finally cut off the connecting ribs of the lead frame structure to obtain the final chip component.

[0054] However, in existing technologies, when cutting a lead frame structure into multiple lead frames, the thickness at the cutting location is relatively large, requiring the cutter to provide a large shearing force. This not only affects cutting efficiency but also easily causes cutter wear, reducing the cutter's service life. Therefore, this invention provides a lead frame structure that, by providing a first groove at the intersection of the first and second connecting ribs, and extending the first groove to the first and / or second connecting ribs, reduces the thickness at the cutting location of the second and first connecting ribs. This reduces the shearing force required by the cutter, improves cutting efficiency, reduces cutter wear, and extends the cutter's service life.

[0055] The technical solution of the present invention will be further described below with reference to the embodiments and accompanying drawings.

[0056] Please see Figures 1 to 4 This invention provides a lead frame structure 100. Specifically, the lead frame structure 100 includes a lead frame 1 and a connecting rib 2. The connecting rib 2 is connected to the outer periphery of the lead frame 1. The connecting rib 2 includes a first connecting rib 21 and a second connecting rib 22. The first connecting rib 21 and the second connecting rib 22 intersect and are connected. A first groove 23 is provided at the intersection of the first connecting rib 21 and the second connecting rib 22. The first groove 23 extends from the intersection to the first connecting rib 21, and / or, the first groove 23 extends from the intersection to the second connecting rib 22.

[0057] like Figure 4As shown, the lead frame structure 100 may have an upper surface and a lower surface opposite each other along the Z direction, and the first groove 23 may be formed on the lower surface of the lead frame structure 100. In the Z direction, the distance D1 from the bottom surface of the first groove 23 to the upper surface of the lead frame structure 100 is less than the thickness D2 of the second connecting rib 22. That is to say, the thickness of the lead frame structure 100 at the first groove 23 is less than the thickness of the second connecting rib 22.

[0058] For example, such as Figure 3 As shown, the first connecting rib 21 has a first surface 211 and a second surface 212 opposite each other along the X direction, and the second connecting rib 22 has a third surface 221 and a fourth surface 222 opposite each other along the Y direction. The first groove 23 extends from the intersection of the first connecting rib 21 and the second connecting rib 22 along the opposite direction of the Y direction and also along the Y direction, such that one groove wall surface of the first groove 23 in the Y direction is located on the third surface 221 and spaced apart from it, and the other groove wall surface is located on the fourth surface 222 and spaced apart from it. In other embodiments, the first groove 23 may also extend from the intersection of the first connecting rib 21 and the second connecting rib 22 along the opposite direction of the X direction and also along the X direction, such that one groove wall surface of the first groove 23 in the X direction is located on the first surface 211 and spaced apart from it, and the other groove wall surface is located on the second surface 212 and spaced apart from it. Figure 4 The dotted lines C1-C1, C2-C2, C3-C3, and C4-C4 in the figure show the cutting path of the lead frame structure 100. The cutter cuts along the cutting path to separate the first connecting rib 21 and the second connecting rib 22 from the lead frame 1. At this time, the first groove 23 is located on the cutting path. Since the thickness of the lead frame structure 100 at the first groove 23 is relatively small in the Z direction, the shearing force required by the cutter is reduced, which is beneficial to improving the cutting efficiency. At the same time, it can effectively reduce the wear of the cutter and improve the service life of the cutter.

[0059] The lead frame 1 includes a base island 11 and pins 12 disposed on the outer periphery of the base island. Multiple pins 12 may be present, and multiple first connecting ribs 21 and multiple second connecting ribs 22 may be provided on the outer periphery of the lead frame 1. All the multiple first connecting ribs 21 and multiple second connecting ribs 22 are connected to the base island 11 and the pins 12. Since the first groove 23 is only provided at the intersection of the second connecting rib 22 and the first connecting rib 21 in this embodiment of the invention, the thickness of the second connecting rib 22 and the first connecting rib 21 at the connection point with the pin 12 is not reduced. Therefore, this helps to ensure the overall strength of the lead frame structure 100. It can prevent the lead frame structure 100 from collapsing due to insufficient thickness of the first connecting ribs 21 and the second connecting ribs 22 in the Z direction when the size of the lead frame structure 100 is large. This would prevent unevenness of the leads when connecting the chip on the base island 11 and the pins 12 during the packaging process, thus affecting the reliability of the chip assembly.

[0060] Among them, the base island 11 can be of various shapes, such as square, circular, elliptical, or oval. For example... Figure 1 and Figure 2 As shown, taking the base island 11 as a square example, a connecting part 111 can be provided at the junction of the two sides of the base island 11. The connecting part 111 extends outward toward the second connecting rib 22 and the first connecting rib 21, and is connected together with the pin 12 to the same side of the second connecting rib 22 and the first connecting rib 21.

[0061] In one example, there are multiple lead frames 1, arranged sequentially in the same direction. A first connecting rib 21 is provided between adjacent lead frames 1, and each first connecting rib 21 intersects with a second connecting rib 22 to form an intersection. A first groove 23 at each intersection connects to the corresponding two adjacent lead frames 1. In this case, only one first connecting rib 21 may be provided between adjacent lead frames 1, and the two adjacent lead frames 1 are respectively connected to the first surface 211 and the second surface 212 of the first connecting rib 21. The first groove 23 may extend from the intersection of the first connecting rib 21 and the second connecting rib 22 to the first connecting rib 21 to connect the two adjacent lead frames 1.

[0062] In another example, there are multiple lead frames 1 arranged in an array. A first connecting rib 21 or a second connecting rib 22 is provided between adjacent lead frames 1 to form an intersection at the midpoint of four adjacent lead frames 1. A first groove 23 at each intersection connects to the corresponding four adjacent lead frames 1. For example, as shown... Figure 3As shown, when multiple lead frames 1 are arranged in an array, two first connecting ribs 21 and two second connecting ribs 22 are formed between four lead frames 1 in two adjacent rows and two columns. The intersection is provided with a first groove 23, and the first groove 23 extends in the opposite direction of the X direction and in the X direction, and in the opposite direction of the Y direction and in the Y direction, so that the four lead frames 1 are connected through the first groove 23.

[0063] During the chip packaging process, the chip and lead frame structure 100 are often placed into a mold first, and then molded and hardened with molding compound before being cut off. Therefore, in this embodiment, when the first groove 23 connects to the adjacent lead frame 1, the high-temperature liquid molding compound in the mold can flow through the first groove 23 to each lead frame 1, so that the molding compound is evenly distributed in the area of ​​each lead frame 1. Moreover, the molding compound can enter the area of ​​the lead frame 1 from the first groove 23 around the lead frame 1, ensuring that each area of ​​the lead frame 1 is filled with molding compound, which can improve the reliability of the chip assembly.

[0064] In some embodiments, such as Figure 3 As shown, the first connecting rib 21 has a direction along the first direction (e.g. Figure 3 The first surface 211 and the second surface 212 are opposite each other on the X direction (as shown in the figure), the first surface 211 is set towards the lead frame 1, and along the second direction (as shown in the figure) Figure 3 In the Y direction (as shown in the diagram), the width L1 of the first connecting rib 21 is consistent in the first direction. And / or, the second connecting rib 22 has a third surface 221 and a fourth surface 222 opposite each other along the second direction, the third surface 221 being disposed towards the lead frame 1, and the width L2 of the second connecting rib 22 being consistent along the first direction. The second direction is perpendicular to the first direction. Since the first connecting rib 21 and the second connecting rib 22 are removed and recycled during the chip assembly fabrication process, this embodiment maintains a consistent width L1 for the first connecting rib 21 along the Y direction and a consistent width L2 for the second connecting rib 22 along the X direction. This ensures that as much material as possible is retained during substrate etching to form the first connecting rib 21 and the second connecting rib 22, so that after packaging, the first connecting rib 21 and the second connecting rib 22 can be removed and recycled, and the substrate can be re-formed to fabricate the lead frame structure, reducing production costs.

[0065] It is understandable that when the first connecting rib 21 is located between two adjacent lead frames 1, the first surface 211 and the second surface 212 can respectively face the two lead frames 1. When the first connecting rib 21 is not located between two adjacent lead frames 1, the first surface 211 faces the lead frame 1, and the second surface may not face the lead frame 1. When the second connecting rib 22 is located between two adjacent lead frames 1, the third surface 221 and the fourth surface 222 can also respectively face the two lead frames 1. When the second connecting rib 22 is not located between two adjacent lead frames 1, if the third surface 221 faces the lead frame 1, then the second surface may not face the lead frame 1.

[0066] Please see Figure 5 , Figure 6 , Figure 8 and Figure 9 In some embodiments, the first connecting rib 21 includes a first part 213 and a second part 214 that are connected to each other, and the second connecting rib 22 includes a third part 223 and a fourth part 224 that are connected to each other. The third part 223 intersects and is connected to the first part 213, and a first groove 23 is provided at the intersection of the third part 223 and the first part 213.

[0067] In one example, such as Figure 6 and Figure 7 As shown, the first portion 213 has opposing first side surface 213a and second side surface 213b. The first side surface 213a faces the lead frame 1 and has a second groove 213c that communicates with the first groove 23. The width of the second groove 213c in the X direction can be 1 / 3 to 2 / 3 of the thickness of the second portion 214 in the X direction, for example, 1 / 3, 2 / 5, 1 / 2, 3 / 5, or 2 / 3. The third portion 223 has opposing third side surface 223a and fourth side surface 223b. The third side surface 223a faces the lead frame 1 and has a third groove 223c that communicates with the first groove 23. The width of the third groove 223c in the Y direction can be 1 / 3 to 2 / 3 of the thickness of the fourth portion 224 in the Y direction, for example, 1 / 3, 2 / 5, 1 / 2, 3 / 5, or 2 / 3.

[0068] In another example, such as Figure 9 , Figure 10 and Figure 11As shown, the first part 213 has opposing first side surface 213a and second side surface 213b. The first side surface 213a faces the lead frame 1. Both the first side surface 213a and the second side surface 213b are provided with a second groove 213c. In this case, the groove width of the second groove 213c in the X direction can be 1 / 5 to 2 / 5 of the thickness of the second part 214 in the X direction, for example, 1 / 5, 1 / 4, 3 / 10 or 2 / 5. The second groove 213c communicates with the first groove 23. The third part 223 has opposing third side surface 223a and fourth side surface 223b. The third side surface 223a faces the lead frame 1. The third side surface 223a and the fourth side surface 223b are provided with a third groove 223c, which communicates with the first groove 23. At this time, the groove width of the third groove 223c in the Y direction can be 1 / 5 to 2 / 5 of the thickness of the fourth part 224 in the Y direction, for example, 1 / 5, 1 / 4, 3 / 10 or 2 / 5.

[0069] It is understandable that by setting a second groove 213c in the first part 213 of the first connecting rib 21 and making the second groove 213c communicate with the first groove 23, it is beneficial to increase the opening size of the communication port of the adjacent lead frame 1, which can facilitate the flow of molding compound without affecting the overall strength of the lead frame structure 100.

[0070] Furthermore, such as Figure 9 , Figure 10 and Figure 11 As shown, the first portion 213 also has a fifth side 213d connected to the first side 213a and the second side 213b. The fifth side 213d is connected to the groove wall of the first groove 23, and the second groove 213c has a first opening 2131 located on the fifth side 213d. The third portion 223 also has a sixth side 223d connected to the third side 223a and the fourth side 223b. The sixth side 223d is connected to the groove wall of the first groove 23, and the third groove 223a has a second opening 2231 located on the sixth side 223d. By extending the second groove 213c toward the fifth side 213d and forming the first opening 2131 on the fifth side 213d, or by extending the third groove 223a toward the sixth side 223d and forming the second opening 2231 on the sixth side 223d, the size of the communication opening of the adjacent lead frame 1 can be maximized, allowing more molding compound to flow. However, it is worth noting that the depth of the second groove 213c in the Z direction must not be greater than the depth of the first groove 23 in the Z direction, and the depth of the third groove 223c in the Z direction must also not be greater than the depth of the first groove 23 in the Z direction, so as to ensure the overall strength of the lead frame structure 100.

[0071] In some embodiments, such as Figure 11As shown, in the third direction, the depth D3 of the first groove 23 is equal to 1 / 3 to 2 / 3 of the thickness D2 of the second connecting rib 22, and the third direction is perpendicular to the plane containing the first connecting rib 21 and the second connecting rib 22. For example, the third direction is as follows... Figure 11 As shown in the Z direction, the depth D3 of the first groove 23 can be equal to 1 / 3, 4 / 9, 1 / 2, 5 / 9, 2 / 3, etc., of the thickness D2 of the second connecting rib 22. By controlling the depth of the first groove 23, it is possible to avoid situations where the depth of the first groove 23 is too large and affects the strength of the lead frame structure, or the depth of the first groove 23 is too small and cannot reduce the shearing force of the cutter to a low range. A balance is achieved between ensuring the overall strength of the lead frame structure 100 and reducing the shearing force required by the cutter.

[0072] Preferably, in this embodiment, the depth D3 of the first groove 23 is equal to half the thickness D2 of the second connecting rib 22.

[0073] Please see Figure 12 Secondly, embodiments of the present invention provide a method for preparing the above-mentioned lead frame structure, the method comprising the following steps:

[0074] S1: Provide a substrate and place a photosensitive film on the substrate.

[0075] The substrate can be made of copper, aluminum, gold or any other conductive material, and the substrate can be a sheet structure with opposing upper and lower surfaces.

[0076] S2: Expose the photosensitive film to form a first patterned area and a second patterned area on the substrate.

[0077] In this step, the photosensitive film can be disposed on the lower surface of the substrate. After exposure treatment, a first patterned area and a second patterned area are formed on the lower surface of the substrate. Alternatively, the photosensitive film can be disposed on both the upper and lower surfaces of the substrate, and the photosensitive films on the upper and lower surfaces of the substrate are exposed respectively to form a first patterned area and a second patterned area on the lower surface, and a third patterned area on the upper surface.

[0078] S3: The substrate is developed and etched to form a lead frame, a first connecting rib and a second connecting rib in the first pattern area, and a first groove in the second pattern area.

[0079] In this step, the first patterned area can be fully etched to form the lead frame 1, the first connecting rib 21, and the second connecting rib 22. The second patterned area can be partially etched to form the first groove, thus obtaining the lead frame structure. Alternatively, the first and third patterned areas can be partially etched to form the lead frame 1, the first connecting rib 21, and the second connecting rib 22. The second patterned area can be partially etched to form the first groove on the lower surface of the substrate, thus obtaining the lead frame structure.

[0080] The above-mentioned lead frame structure 100 can be prepared by this preparation method. The first groove 23 is provided at the position of the first connecting rib 21 and the second connecting rib 22 on the cutting channel, which can reduce the material thickness cut by the cutter and reduce the shearing force required by the cutter during cutting, thereby improving the cutting efficiency. At the same time, it can effectively reduce the wear of the cutter and increase the service life of the cutter.

[0081] In some embodiments, when etching the lead frame 1, the first connecting rib 21 and the second connecting rib 22 in the first pattern area or the third pattern area, half etching can be performed on the substrate at the position of the connecting portion 111 corresponding to the base island 11 to reduce the thickness of the connecting portion 111, further reduce the shearing force required by the cutter, improve the cutting efficiency of the cutter, reduce the wear of the cutter, and improve the service life of the cutter.

[0082] In some embodiments, the preparation method further includes adhering adhesive tape to the surface of the substrate. Specifically, after developing and etching the substrate, the adhesive tape can be adhered to the lower surface of the substrate to prevent the high-temperature liquid molding compound from leaking to the lower surface of the substrate when the chip and lead frame structure 100 are placed into the mold and molding compound is injected into the mold for baking and curing encapsulation.

[0083] Furthermore, there are multiple lead frames 1, and when the first groove 23 connects to adjacent lead frames, the tape adheres to the lower surface of the substrate. Although the tape covers the opening of the first groove 23 on the lower surface, the first groove 23 can still connect to adjacent lead frames 1, allowing the molding compound to flow through the first groove 23 to each lead frame 1 and be evenly distributed in the area of ​​each lead frame 1, ensuring that each area of ​​the lead frame 1 is filled with molding compound, thereby improving the reliability of the chip assembly.

[0084] Thirdly, embodiments of the present invention provide a packaging structure including a chip, leads, and the aforementioned lead frame structure 100. The lead frame 1 includes a base island 11 and pins 12 disposed on the outer periphery of the base island. The chip is disposed on the base island 11, and the leads connect the chip and the pins 12. Because this packaging structure includes the aforementioned lead frame structure 100, when cutting it into chip assemblies, it helps to reduce the shearing force required by the cutter, thereby improving cutting efficiency and thus increasing the production efficiency of chip assemblies. Furthermore, it can reduce cutter wear, extend cutter life, and reduce the manufacturing cost of chip assemblies.

[0085] Fourthly, embodiments of the present invention provide a chip assembly manufactured by cutting the aforementioned packaging structure. Since the chip assembly is manufactured by cutting the aforementioned packaging structure, the shearing force required by the cutter is reduced during the chip assembly manufacturing process, thereby improving cutting efficiency and thus increasing the production efficiency of the chip assembly. Furthermore, it reduces cutter wear, extends cutter lifespan, and reduces the manufacturing cost of the chip assembly.

[0086] Fifthly, embodiments of the present invention also provide a terminal, which includes a circuit board and the aforementioned chip assembly, the chip assembly being electrically connected to the circuit board. The terminal includes, but is not limited to, mobile phones, tablets, or smartwatches. Because the terminal includes the aforementioned chip assembly, during the manufacturing process of the terminal, it is beneficial to reduce the shearing force required by the cutter, thereby improving cutting efficiency and ultimately increasing the production efficiency of the terminal. Furthermore, it can reduce cutter wear, extend the cutter's service life, and reduce the manufacturing cost of the terminal.

[0087] The lead frame structure, its preparation method, packaging structure, chip assembly, and terminal disclosed in the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the lead frame structure, its preparation method, packaging structure, chip assembly, terminal, and its core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A lead frame structure, characterized in that, The lead frame structure includes: A lead frame, the lead frame including a base island and pins disposed on its outer periphery, the base island being used to mount a chip; and A connecting rib is connected to the outer periphery of the lead frame and to the pin. The connecting rib includes a first connecting rib and a second connecting rib. The first connecting rib and the second connecting rib intersect and are connected. A first groove is provided at the intersection of the first connecting rib and the second connecting rib. The first groove extends from the intersection to the first connecting rib, and / or the first groove extends from the intersection to the second connecting rib. The first connecting rib includes a first part and a second part that are connected to each other, and the second connecting rib includes a third part and a fourth part that are connected to each other. The third part intersects and connects with the first part, and the first groove is provided at the intersection of the third part and the first part. The first portion has opposing first and second sides, the first side facing the lead frame, and the first side and / or the second side having a second groove communicating with the first groove; and / or, The third part has opposing third and fourth sides, the third side facing the lead frame, and the third side and / or the fourth side is provided with a third groove, the third groove communicating with the first groove.

2. The lead frame structure according to claim 1, characterized in that, The lead frame comprises multiple lead frames arranged sequentially in the same direction. A first connecting rib is provided between two adjacent lead frames, and each first connecting rib intersects and connects with a second connecting rib to form an intersection. A first groove at each intersection communicates with the corresponding two adjacent lead frames; or The lead frame is a plurality of such lead frames, which are arranged in an array. A first connecting rib or a second connecting rib is provided between two adjacent lead frames to form an intersection at the middle of four adjacent lead frames. The first groove at each intersection is connected to the corresponding four adjacent lead frames.

3. The lead frame structure according to claim 1, characterized in that, The first portion further has a fifth side connecting the first side and the second side, the fifth side connecting to the groove wall of the first groove, the second groove having a first opening located on the fifth side; and / or, The third part also has a sixth side connecting the third side and the fourth side, the sixth side connecting the groove wall of the first groove, and the third groove having a second opening located on the sixth side.

4. The lead frame structure according to claim 1, characterized in that, The first connecting rib has a first surface and a second surface opposite each other along a first direction, the first surface is disposed facing the lead frame, and the width of the first connecting rib is consistent along the second direction in the first direction; And / or, The second connecting rib has a third and a fourth face opposite each other along a second direction, the third face being disposed toward the lead frame, and the width of the second connecting rib is consistent along the first direction in the second direction; The second direction is perpendicular to the first direction.

5. The lead frame structure according to any one of claims 1-4, characterized in that, In the third direction, the depth of the first groove is 1 / 3 to 2 / 3 of the thickness of the second connecting rib, and the third direction is perpendicular to the plane containing the first connecting rib and the second connecting rib.

6. A method for preparing a lead frame structure as described in any one of claims 1-5, characterized in that, The preparation method includes the following steps: A substrate is provided, and a photosensitive film is disposed on the surface of the substrate; The photosensitive film is exposed to form a first patterned area and a second patterned area on the substrate; The substrate is subjected to development and etching processes to form the lead frame, the first connecting rib, and the second connecting rib in the first patterned area, and to form the first groove in the second patterned area.

7. A packaging structure, characterized in that, The package structure includes a chip, leads, and a lead frame structure as described in any one of claims 1-5, wherein the chip is disposed on a base island of the lead frame, and the leads connect the chip and the pins of the lead frame.

8. A chip assembly, characterized in that, The chip assembly is cut from the packaging structure described in claim 7.

9. A terminal, characterized in that, The terminal includes a circuit board and a chip assembly as described in claim 8, wherein the chip assembly is electrically connected to the circuit board.

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