Lead frame

Abstract

The invention provides a lead frame. The lead frame comprises a frame body and at least one connecting unit located in the frame body. The connecting unit comprises a plurality of pins, two oppositely arranged connecting ribs and a connecting part. The plurality of pins are located between the two connecting ribs, the ends, facing the connecting ribs, of the pins are connected with the connecting ribs, and each connecting rib is connected with the plurality of pins. The connecting part comprises two opposite end parts, one end part is connected with the connecting rib, and the other end part is connected with the frame body. According to the lead frame, the semiconductor structure comprising the pins can be prevented from being separated from the frame body when the lead frame is used for preparing the semiconductor structure, the problems that the die is damaged and the semiconductor structure is damaged by the die due to the fact that the semiconductor structure falls on the die used for preparing the semiconductor structure are solved, the manufacturing cost is reduced, and the production efficiency is improved. And the product yield is improved.

Description

Technical Field

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

[0002] Common semiconductor packaging technologies, such as chip packaging technology, usually include the following process: providing a lead frame, the lead frame includes a frame body, a base island located in the frame body and a plurality of pins, the base island is connected to the frame body through suspension ribs; mounting the chip on the base island; then forming a plastic encapsulation layer that encapsulates the chip, the base island and some of the pins, and the plastic encapsulation layer is exposed at the ends of the frame body and the pins connected to the frame body; using a cutting mold to cut the pins to separate the pins from the frame body; using a cutting mold to cut off the suspension ribs to separate the base island from the frame body.

[0003] The strength of the existing lead frame hangers is relatively low. After the pins are cut by a cutting mold to separate the pins from the frame body, the hangers are prone to breakage and separation from the frame body, causing the semiconductor structure including the chip, plastic encapsulation layer, base island and pins to separate from the frame body and fall onto the cutting mold, which can easily damage the mold and the semiconductor structure, affecting the product yield. Summary of the invention

[0004] The embodiment of the present application provides a lead frame. The lead frame includes a frame body and at least one connecting unit located in the frame body; the connecting unit includes:

[0005] Multiple pins;

[0006] Two connecting bars are arranged opposite to each other, the plurality of pins are located between the two connecting bars, and the ends of the pins facing the connecting bars are connected to the connecting bars, and each connecting bar is connected to the plurality of pins respectively;

[0007] A connecting portion is connected to the connecting rib and to the frame body.

[0008] In one embodiment, the pin includes a straight portion, and the straight portion is connected to the connecting rib; the straight portion and the connecting portion of each pin connected to the same connecting rib are arranged in parallel.

[0009] In one embodiment, the frame body includes a first frame portion, the extension direction of the first frame portion is the same as the extension direction of the connecting rib, the two ends of the connecting portion adjacent to the first frame portion are respectively connected to the frame body, and the end of the connecting portion facing the first frame portion is connected to the first frame portion.

[0010] In one embodiment, two adjacent connection portions located in different connection units extend in the same direction and their ends are connected.

[0011] In one embodiment, in the connection unit, among the plurality of pins and the connection parts connected to the same connecting rib, each connection part is located on the same side of each pin.

[0012] In one embodiment, the connection unit includes at least two connection parts connected to the same connection bar, and among the plurality of pins and the connection parts connected to the same connection bar, the at least two connection parts are symmetrically distributed on both sides of the pin.

[0013] In one embodiment, in the same connecting unit, the number of the connecting parts adjacent to two connecting bars is the same.

[0014] In one embodiment, in the extension direction of the connecting reinforcement, the frame body includes a second frame portion located on the side of the connecting reinforcement; the second frame portion includes a main body portion and an extension portion formed by extending the main body portion toward the connecting unit; one end of each of the connecting portions is respectively connected to one of the extension portions.

[0015] In one embodiment, the width of the connecting portion is less than or equal to the width of the pin; and / or,

[0016] The connection unit further includes a first connecting rod located between adjacent connecting ribs, the first connecting rod is connected to the plurality of pins, and the connecting portion is connected to the first connecting rod.

[0017] In one embodiment, the connecting unit also includes a base island located between the two connecting ribs, a second connecting rod connected to the base island, and a connecting rib connected to the side of the second connecting rod away from the base island. In the same connecting unit, the multiple pins are arranged around the base island; the end of the connecting rib away from the second connecting rod is connected to the frame body; the width of the connecting rib is smaller than the width of the connecting portion.

[0018] The main technical effects achieved by the embodiments of the present application are:

[0019] The lead frame provided in the embodiment of the present application includes a connecting portion, and the connecting portion is respectively connected to the connecting rib and the frame body. In the process of using the lead frame to form a semiconductor structure, before the pins are separated from the connecting ribs, the semiconductor structure including the pins is connected to the frame body through the connecting ribs and the connecting portion, and the pins of the semiconductor structure can be separated from the connecting ribs without separating the connecting portion from the frame body and the connecting ribs. In other words, the semiconductor structure can be obtained without cutting the connecting portion to separate it from the frame body and the connecting ribs. The strength of the connecting portion can be set to be relatively large to ensure that the connection between the connecting portion and the connecting ribs and the frame body is relatively firm, so as to ensure that the connecting portion will not break before the pins are separated from the connecting ribs, thereby avoiding the connection portion from breaking and causing the semiconductor structure to separate from the frame body, thereby improving the problem of the semiconductor structure falling on the mold used to prepare the semiconductor structure, thereby causing damage to the mold and the semiconductor structure being damaged by the mold, which helps to reduce manufacturing costs and improve product yields. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a top view of a lead frame provided by an exemplary embodiment of the present application;

[0021] Figure 2 is a schematic diagram of a three-dimensional structure of a first intermediate structure provided by an exemplary embodiment of the present application;

[0022] Figure 3 is a schematic diagram of a three-dimensional structure of a partial structure of a second intermediate structure provided by an exemplary embodiment of the present application;

[0023] Figure 4 is a three-dimensional structural schematic diagram of a partial structure of a third intermediate structure provided by an exemplary embodiment of the present application;

[0024] Figure 5 is a schematic three-dimensional structural diagram of a partial structure of a fourth intermediate structure provided by an exemplary embodiment of the present application;

[0025] Figure 6 It is a three-dimensional structural schematic diagram of a semiconductor structure and a partial structure of a frame body provided by an exemplary embodiment of the present application. Specific embodiments

[0026] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0027] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0028] It should be understood that although the terms first, second, third, etc. may be used in the present application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0029] Some embodiments of the present application are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0030] The present application embodiment provides a lead frame. Figure 1 As shown, the lead frame 100 includes a frame body 110 and at least one connection unit 120 located in the frame body 110. The connection unit 120 includes a plurality of pins 10, two oppositely disposed connecting ribs 20 and a connection portion 30. The plurality of pins 10 are located between two connecting ribs 20, and the ends of the pins 10 facing the connecting ribs 20 are connected to the connecting ribs 20, and each connecting rib 20 is respectively connected to a plurality of the pins 10. The connection portion 30 is connected to the connecting ribs 20 and to the frame body 110.

[0031] The lead frame provided in the embodiment of the present application includes a connecting portion, and the connecting portion is respectively connected to the connecting rib and the frame body. In the process of using the lead frame to form a semiconductor structure, before the pins are separated from the connecting ribs, the semiconductor structure including the pins is connected to the frame body through the connecting ribs and the connecting portion, and the pins of the semiconductor structure can be separated from the connecting ribs without separating the connecting portion from the frame body and the connecting ribs. In other words, the semiconductor structure can be obtained without cutting the connecting portion to separate it from the frame body and the connecting ribs. The strength of the connecting portion can be set to be relatively large to ensure that the connection between the connecting portion and the connecting ribs and the frame body is relatively firm, so that the connecting portion will not break before the pins are separated from the connecting ribs, thereby avoiding the connection portion from breaking and causing the semiconductor structure to separate from the frame body, thereby improving the problem of the semiconductor structure falling on the mold used to prepare the semiconductor structure, causing damage to the mold, and the semiconductor structure being damaged by the mold, which helps to reduce manufacturing costs and improve product yields.

[0032] In one embodiment, Figure 1 As shown, the pin 10 includes a straight portion 11 and a non-straight portion 12 connected to the straight portion 11. The non-straight portion 12 may be roughly in a broken line shape. The end of the straight portion 11 away from the non-straight portion 12 is connected to the connecting rib 20, and the straight portions 11 of the pins 10 connected to the same connecting rib 20 are arranged side by side.

[0033] In one embodiment, Figure 1 As shown, the straight portion 11 of each pin 10 and the connecting portion 30 connected to the same connecting rib 20 are arranged side by side. The connecting portion 30 may be in a straight line.

[0034] In one embodiment, Figure 1 As shown, the frame body 110 is annular, and each connecting unit 120 is located in a space enclosed by the frame body 110 . Figure 1 In the illustrated embodiment, the frame body 110 is in a square ring shape.

[0035] In one embodiment, Figure 1 As shown, the frame body 110 includes two first frame parts 111 and two second frame parts 112. The two first frame parts 111 of the frame body 110 are arranged opposite to each other, and the two second frame parts 112 are arranged opposite to each other. The two ends of each first frame part 111 are respectively connected to a second frame part 112, and the two ends of each second frame part 112 are respectively connected to a first frame part 111. The extension direction of the first frame part 111 is the same as the extension direction of the connecting rib 20. In the extension direction of the connecting rib 20, the second frame part 112 is located on the side of the connecting rib 20. The length of the second frame part 112 is greater than the length of the first frame part 111. The extension direction of the second frame part 112 and the extension direction of the first frame part 111 may be perpendicular to each other.

[0036] In one embodiment, the frame body 110 may include a plurality of second frame portions 112 arranged in parallel, and a plurality of connection units 120 of the lead frame may be arranged in a plurality of columns, with a column of connection units 120 provided between two adjacent frame portions 112 , and a column of connection units may include a plurality of connection units 120 .

[0037] In one embodiment, Figure 1 As shown, the second frame portion 112 includes a main body 113 and an extension portion 114 formed by the main body 113 extending toward the connection unit 120; one end of each of the connection portions 30 is connected to one of the extension portions 114. Specifically, the end of the connection portion 30 that is farther from the connecting rib 20 connected thereto is connected to the side of the extension portion 114 toward one of the first frame portions 111. The provision of the extension portion 114 facilitates the connection of the connection portion 30 to the frame body 110.

[0038] In one embodiment, Figure 1 As shown, the lead frame 100 includes a plurality of connection units 120 , and the plurality of connection units 120 are arranged at intervals in the length direction of the second frame portion 112 .

[0039] In one embodiment, Figure 1 As shown, the two ends of the connecting portion 30 adjacent to the first frame portion 111 are respectively connected to the frame body 110, and the end of the connecting portion 30 facing the first frame portion 111 is connected to the first frame portion 111. The portion of the connecting portion 30 adjacent to the first frame portion 111 located between the two ends is connected to the connecting rib 20. Among them, the connecting portion 30 adjacent to the first frame portion 111 refers to the connecting portion 30 with the smallest distance from the first frame portion 111. By setting the two ends of the connecting portion 30 adjacent to the first frame portion 111 to be connected to the frame body 110 respectively, both ends of the connecting portion 30 are not suspended, which can avoid that one end of the connecting portion 30 is suspended and causes the connecting rib 20 connected to the connecting portion 30 to sag under the action of gravity and cause the lead frame 100 to deform, which helps to improve the quality of the semiconductor structure prepared by the lead frame 100; the end of the connecting portion 30 facing the first frame portion 111 is connected to the first frame portion 111, which facilitates the connection of the connecting portion 30 with the lead frame 100. Figure 1 In the illustrated embodiment, one end of the connecting portion 30 which is at a smaller distance from the connecting rib 20 is connected to the first frame portion 111 , and the other end is connected to the extending portion 114 .

[0040] In one embodiment, Figure 1 As shown, two adjacent connecting portions 30 located in different connecting units 120 extend in the same direction and their ends are connected. That is, in two adjacent connecting units 120, the connecting portion 30 of one connecting unit 120 extends in the same direction and their ends are connected with the connecting portion 30 adjacent to the connecting portion 30 in the other connecting unit 120. The two adjacent connecting portions 30 extending in the same direction are connected at the ends that are smaller than the connecting ribs 20. In this way, two adjacent connecting ribs 20 are connected through the two connecting portions 30, which can prevent the adjacent ends of the two connecting portions 30 from being suspended in the air, thereby preventing the connecting ribs 20 connected to the two connecting portions 30 from sagging under the action of gravity and causing the lead frame 100 to deform, which helps to improve the quality of the semiconductor structure prepared using the lead frame 100.

[0041] In some embodiments, one end of the connection portion 30 adjacent to the first frame portion 111 is connected to the first frame portion 111, and two adjacent connection portions 30 located in different connection units 120 extend in the same direction and are connected at their ends. This arrangement can improve the situation where all the connecting ribs sag under the action of gravity, and is more helpful to ensure the quality of the semiconductor structure prepared by the lead frame 100.

[0042] In one embodiment, Figure 1 As shown, the connection unit 120 further includes a base island 80, and the base island 80 is located between the two connecting ribs 20. In the same connection unit 120, the plurality of pins 10 are arranged around the base island 80. Specifically, the non-straight portions 12 of the plurality of pins 10 are arranged around the base island 80. The non-straight portions 12 of all the pins 10 in the same connection unit 120 may be distributed on each side of the base island 80, and the straight portions 11 of all the pins 10 in the same connection unit 120 are distributed on opposite sides of the base island 80.

[0043] In one embodiment, Figure 1 As shown, the connection unit 120 also includes a first connecting rod 40 located between the two connecting ribs 20, and the first connecting rod 40 is connected to the plurality of pins 10. The connecting portion 30 is connected to the first connecting rod 40. Specifically, the first connecting rod 40 is connected to the region between the two ends of the pin 10. By providing the first connecting rod 40, the strength of the lead frame can be improved, and the first connecting rod 40 is connected to the frame body 110 through the connecting portion 30, which can prevent the region between the two ends of the pin 40 from sagging due to the excessive length of the pin 40 under the action of gravity, thereby affecting the quality of the formed semiconductor structure.

[0044] In some embodiments, each connection unit 120 may include two first connecting rods 40, each of which is located between the base island 80 and a connecting rib 20. The first connecting rod 40 and the connecting rib 20 are both connected to the straight portion 11 of the pin 10.

[0045] In one embodiment, Figure 1 As shown, the connecting unit 120 further includes a second connecting rod 50 connected to the base island 80 and a connecting rib 60 connected to the side of the second connecting rod 50 away from the base island 80, and the end of the connecting rib 60 away from the second connecting rod 50 is connected to the frame body 110. The extension direction of the second connecting rod 50 may be the same as the extension direction of the connecting rib 20. The connecting rib 60 may be connected to the extension portion 114 of the second frame portion 112.

[0046] In one embodiment, Figure 1As shown, the end of the second connecting rod 50 away from the base island 60 includes two sub-connecting rods 51, and each sub-connecting rod 51 is respectively connected to a connecting rib 60. In this way, the firmness of the connection between the second connecting rod 50 and the frame body 110 can be improved.

[0047] In one embodiment, the process of using the lead frame provided in the embodiment of the present application to prepare a semiconductor structure may be as follows:

[0048] First, an electrical component is mounted on the base island of the lead frame, and the electrode of the electrical component can be electrically connected to the non-straight portion of the lead. The electrical component can be a chip.

[0049] Subsequently, a plastic encapsulation layer is formed to encapsulate the electrical components, the base island and a portion of each pin, thereby obtaining a plastic encapsulation structure including the plastic encapsulation layer, the electrical components, the base island and the pins. Each plastic encapsulation structure includes a base island and a pin of a connection unit.

[0050] Through this step, we can obtain Figure 2 The first intermediate structure shown. Figure 2 As shown, the first intermediate structure includes a plurality of plastic encapsulation structures 70 , and the plastic encapsulation layer 71 of each plastic encapsulation structure 70 can encapsulate the non-straight portion and part of the straight portion of the pin 10 , and can encapsulate the second connecting rod. The plastic encapsulation structure 70 does not encapsulate the first connecting rod 40 .

[0051] Subsequently, the first connecting rod is removed.

[0052] In this step, the first connecting rod can be removed by cutting. Figure 3 The second intermediate structure is shown. Figure 3 It is a structural schematic diagram of a partial structure of the second intermediate structure.

[0053] Then, the connecting ribs are cut to separate the second frame portion from the plastic packaging structure.

[0054] Through this step, we can obtain Figure 4 The third intermediate structure shown. Figure 4 As shown, the connecting ribs between the second frame portion 112 and the plastic packaging structure 70 are cut off, and the plastic packaging structure 70 is connected to the frame body 110 through the connecting portion 30 .

[0055] In one embodiment, the width of the connecting rib 60 is smaller than the width of the connecting portion 30. This can reduce the difficulty of cutting the connecting rib 60, and after the connecting rib 60 is cut off, the plastic package structure 70 is connected to the structure of the frame body through the connecting portion 30, so that the connecting portion 30 and the frame body are firmly connected, thereby ensuring that the semiconductor structure and the frame body are more firmly connected, and preventing the connecting rib and the semiconductor structure from being separated from the frame body as a whole and falling on the cutting mold used to cut the connecting rib.

[0056] Then, the pins are bent.

[0057] Through this step, we can obtain Figure 5 The fourth intermediate structure shown. Figure 5 As shown, after the straight portion 11 of each pin 10 is bent, a portion of the straight portion 11 connected to the connecting rib 20 remains straight, and the surface of the portion can be flush with the surface of the plastic layer 71, so that the semiconductor structure can be connected to other structures through the pin. Since the connecting portion 30 and the pin 10 are arranged side by side, the connecting portion 30 can be bent at the same time as the pin 10, and there is no need to avoid the connecting portion 30 when bending the pin 10, which can reduce the difficulty of bending the pin 10.

[0058] In one embodiment, when the second intermediate structure includes the first frame portion 111, before the step of bending the pin, the process of using the lead frame provided in the embodiment of the present application to prepare a semiconductor structure may also include the following steps: cutting the connecting portion 30 to separate the connecting portion 30 from the first frame portion 111. During the bending process of the pin, the relative position of the connecting rib 20 and the frame body 110 will change. If the connecting portion 30 is separated from the first frame portion 111 before the step of bending the pin, the connecting rib 20 is also separated from the first frame portion 111, so as to avoid the first frame portion applying a force on the connecting rib and affecting the bending process of the pin. After the connecting portion 30 is separated from the first frame portion 111, the other end of the connecting portion 30 is connected to the extension portion 114.

[0059] Subsequently, a cutting die is used to cut the pins to separate the pins from the connecting ribs.

[0060] Through this step, we can obtain Figure 6 The semiconductor structure and part of the frame structure shown. Figure 6 As shown, the semiconductor structure is separated from the structure of the frame body.

[0061] In one embodiment, Figure 1 As shown, in the connection unit 120, among the plurality of pins 10 and the connection parts 30 connected to the same connecting rib 20, each connection part 30 is located on the same side of each pin 10. With such arrangement, in the step of cutting the pins with a cutting die to separate the pins from the connecting rib, the plurality of pins 10 can be cut at the same time, making it easy to avoid the connection part 30, which helps to prevent the connection part 30 from being cut.

[0062] In one embodiment, Figure 1As shown, the connection unit 120 includes at least two connection parts 30 connected to the same connecting rib 20, and among the plurality of pins 10 and the connection parts 30 connected to the same connecting rib 20, the at least two connection parts 30 are symmetrically distributed on both sides of the pin 10. Such an arrangement can make the forces at both ends of the same connecting rib 20 relatively uniform, and prevent the deformation of the lead frame caused by uneven forces at both ends of the connecting rib 20.

[0063] Furthermore, in the same connecting unit 120, the number of the connecting parts adjacent to the two connecting bars 20 is the same. Figure 5 After the fourth intermediate structure is shown, both sides of each packaging structure are subjected to uniform force, which can avoid deformation of the pins 10 and the connecting portion 30 caused by uneven force on both sides of the packaging structure.

[0064] In one embodiment, the width of the connecting portion 30 is less than or equal to the width of the pin 10. This arrangement can reduce the difficulty of cutting the connecting portion 30 while ensuring that the connecting portion 30 firmly connects the connecting rib 20 to the frame body 110.

[0065] It should be noted that in the accompanying drawings, the sizes of layers and regions may be exaggerated for clarity of illustration. It is also understood that when an element or layer is referred to as being "on" another element or layer, it may be directly on the other element, or there may be an intermediate layer. In addition, it is understood that when an element or layer is referred to as being "under" another element or layer, it may be directly under the other element, or there may be more than one intermediate layer or element. In addition, it is also understood that when a layer or element is referred to as being "between" two layers or two elements, it may be the only layer between the two layers or two elements, or there may also be more than one intermediate layer or element. Similar reference numerals throughout the text indicate similar elements.

[0066] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the disclosure disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0067] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A lead frame, characterized in that: The lead frame includes a frame body and at least one connecting unit located in the frame body; the connecting unit includes: Multiple pins; Two connecting bars are arranged opposite to each other, the plurality of pins are located between the two connecting bars, and the ends of the pins facing the connecting bars are connected to the connecting bars, and each connecting bar is connected to the plurality of pins respectively; A connecting portion is connected to the connecting rib and to the frame body.

2. The lead frame according to claim 1, characterized in that: The pin includes a straight portion, and the straight portion is connected to the connecting rib; the straight portion and the connecting portion of each pin connected to the same connecting rib are arranged in parallel.

3. The lead frame according to claim 2, characterized in that: The frame body includes a first frame portion, the extension direction of the first frame portion is the same as the extension direction of the connecting rib, the two ends of the connecting portion adjacent to the first frame portion are respectively connected to the frame body, and one end of the connecting portion facing the first frame portion is connected to the first frame portion.

4. The lead frame according to claim 1, wherein: Two adjacent connecting portions located in different connecting units extend in the same direction and their ends are connected.

5. The lead frame according to claim 1, wherein: In the connection unit, among the plurality of pins and the connection parts connected to the same connecting rib, each connection part is located on the same side of each pin.

6. The lead frame according to claim 5, characterized in that: The connection unit includes at least two connection parts connected to the same connection bar, and among the plurality of pins and the connection parts connected to the same connection bar, the at least two connection parts are symmetrically distributed on both sides of the pin.

7. The lead frame according to claim 6, characterized in that: In the same connection unit, the number of the connection parts adjacent to two connecting bars is the same.

8. The lead frame according to claim 1, wherein: In the extension direction of the connecting reinforcement, the frame body includes a second frame portion located on the side of the connecting reinforcement; the second frame portion includes a main body portion and an extension portion formed by extending the main body portion toward the connecting unit; one end of each of the connecting portions is respectively connected to one of the extension portions.

9. The lead frame according to claim 1, characterized in that: The width of the connecting portion is less than or equal to the width of the pin; and / or, The connection unit further includes a first connecting rod located between adjacent connecting ribs, the first connecting rod is connected to the plurality of pins, and the connecting portion is connected to the first connecting rod.

10. The lead frame according to claim 1, wherein: The connecting unit also includes a base island located between the two connecting ribs, a second connecting rod connected to the base island, and a connecting rib connected to the side of the second connecting rod away from the base island. In the same connecting unit, the multiple pins are arranged around the base island; the end of the connecting rib away from the second connecting rod is connected to the frame body; the width of the connecting rib is smaller than the width of the connecting part.

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