A lead frame package structure with electromagnetic shielding

Abstract

The application provides a lead frame package structure with electromagnetic shielding, which comprises a lead frame with a base island and a pin; a chip structure arranged on the upper surface of the base island; a plastic encapsulation layer covering the chip structure, wherein the plastic encapsulation layer is formed with a first step groove and a second step groove on the side wall away from the upper surface of the lead frame, and the first step groove is arranged close to the surface of the plastic encapsulation layer away from the lead frame; a grounding metal layer arranged on the surface of the first step groove, and the surface of the second step groove is not provided with the grounding metal layer; an electromagnetic shielding wire electrically connected to the upper surface of the grounding metal layer; and a grounding wire electrically connected to the grounding metal layer and the grounding pin respectively. Through the structure, the electromagnetic shielding structure can be formed by wire bonding in the package structure of the lead frame, and the electromagnetic shielding wires do not need to be connected by direct contact structure, so that the wire bonding difficulty of the electromagnetic shielding wires can be greatly reduced.

Description

Technical Field

[0001] This application relates to the field of semiconductor packaging, and more particularly to a lead frame packaging structure with electromagnetic shielding. Background Technology

[0002] Electromagnetic shielding structures in semiconductor devices are primarily used to prevent electromagnetic interference (EMI) and electromagnetic leakage (EMC). Semiconductor devices generate electromagnetic waves during operation, which can interfere with surrounding electronic equipment. Electromagnetic shielding structures can block these electromagnetic waves from propagating outward, reducing interference to other devices. For example, on a computer motherboard, various semiconductor chips and electronic components are densely distributed. Without electromagnetic shielding measures, interference between chips can lead to signal transmission errors, logic gate malfunctions, and other problems. Electromagnetic shielding structures can effectively suppress electromagnetic waves generated by these internal interference sources, ensuring the normal operation of the entire electronic system. Simultaneously, external electromagnetic waves can also interfere with the normal operation of semiconductor devices. Electromagnetic shielding structures can provide a relatively stable electromagnetic environment for semiconductor devices, preventing external electromagnetic attacks, such as electromagnetic pulses (EMPs), from damaging the internal structure of the device. When electromagnetic waves encounter a shielding layer, they are attenuated through reflection, absorption, and scattering. Electromagnetic shielding structures can reflect, absorb, and scatter external electromagnetic waves, preventing them from entering the semiconductor device and thus protecting it from external electromagnetic interference. Electromagnetic shielding structures are typically made of highly conductive materials, such as metals like copper, aluminum, and silver, or conductive polymer composites.

[0003] Existing electromagnetic shielding technology using electromagnetic shielding wires can only be used in substrate-based packages. Because the substrate contains internal wiring, the bonding wires spanning the chip surface can be connected to a single ground signal through these internal circuitry, thus achieving electromagnetic shielding. However, for leadframe-based packages, the leadframe only has pins. These pins are used to transmit various signals between the chip and external circuits, and each pin transmits a different electrical signal. Since the electromagnetic shielding wire only transmits a single ground signal, it is impossible to achieve electromagnetic shielding by creating a cross-chip electromagnetic shielding line by bonding wires to the pins. Summary of the Invention

[0004] The problem this application aims to solve is to provide a lead frame packaging structure with electromagnetic shielding, which enables the electromagnetic shielding structure to be formed on the lead frame packaging structure by wire bonding.

[0005] To address the aforementioned problems, this application provides a lead frame packaging structure with electromagnetic shielding, comprising:

[0006] A lead frame, the lead frame including a base island and pins disposed outside the base island, the pins including grounded pins and non-grounded pins;

[0007] A chip structure, wherein the chip structure is disposed on the upper surface of the base island;

[0008] A molding compound is located on the surface of the lead frame and covers the chip structure, and exposes the lower surface of the lead frame. The molding compound has a first stepped groove formed on the sidewall near the upper surface of the lead frame.

[0009] A grounding metal layer is located on the bottom wall of the groove of the first step, and the grounding metal layer is not in direct contact with the pin.

[0010] An electromagnetic shielding wire is located within the molding compound and spans across the chip structure on the side away from the lead frame, and the ends of the electromagnetic shielding wire are electrically connected to the upper surface of the opposite ground metal layer.

[0011] A grounding wire, the two ends of which are electrically connected to the surface of the grounding metal layer and at least one grounding pin of the lead frame, respectively;

[0012] The connection ends of the grounding wire and / or electromagnetic shielding wire that are respectively connected to the grounding metal layer are located on the bottom wall of the first step groove, which is the bottom wall where the plastic seal layer and the grounding metal layer are connected.

[0013] By forming a first stepped groove on the molding compound, and a grounding metal layer on the bottom wall of the first stepped groove, and electrically connecting the grounding metal layer and the grounding pin of the leadframe via a grounding wire, the electromagnetic shielding wire can be electrically connected to the grounding pin of the leadframe in sequence through the grounding metal layer and the grounding wire, thereby forming electromagnetic shielding above and to the side of the chip structure. In other words, this structural design allows the electromagnetic shielding structure to be formed within the leadframe package structure via wire bonding (electromagnetic shielding wire).

[0014] In an optional embodiment, the molding layer has a second stepped groove on the surface near the lead frame, and the first stepped groove is located at the bottom of the second stepped groove, thereby preventing the grounding metal layer from directly contacting the pin.

[0015] The second-step groove can block the connection between the grounding metal layer and the non-grounded pins of the lead frame, except for the grounding pins.

[0016] In an optional embodiment, the first stepped groove and the second stepped groove are respectively annular stepped grooves arranged in a circumferential direction around the chip structure;

[0017] The grounding metal layer is a continuous annular connecting ring arranged in a circumferential direction around the chip structure.

[0018] By setting a continuous annular grounding metal layer around the chip structure, the outer periphery of the chip structure has continuous electromagnetic shielding, thereby giving the packaging structure a better electromagnetic shielding effect.

[0019] In an optional embodiment, the grounding metal layer is located on the bottom surface of the first stepped groove and contacts the side surface of the first stepped groove.

[0020] In an optional embodiment, the first stepped groove includes a plurality of first stepped grooves arranged circumferentially around the chip structure;

[0021] The grounding metal layer has multiple pieces, and the multiple pieces of the grounding metal layer are correspondingly arranged with multiple first step grooves.

[0022] In an optional embodiment, the horizontal plane of the bottom surface of the first stepped groove is lower than the horizontal plane of the upper surface of the chip structure on the side away from the lead frame.

[0023] In an optional embodiment, the horizontal plane containing the bottom surface of the second stepped groove is at least lower than the horizontal plane containing the upper surface of the chip structure on the side away from the lead frame.

[0024] In an optional embodiment, the height of the grounding metal layer is less than or equal to the side height of the first step groove.

[0025] In an optional embodiment, the bottom surface of the second stepped groove is at a level higher than or level with the upper surface of the lead frame pins on the side closest to the chip structure.

[0026] In an optional embodiment, the horizontal plane of the bottom surface of the first stepped groove is lower than the horizontal plane of the upper surface of the chip structure on the side away from the lead frame.

[0027] In an optional embodiment, it further includes bonding wires located within the molding compound;

[0028] The two ends of the bonding wire are electrically connected to the pins of the chip structure and the lead frame, respectively.

[0029] In an alternative embodiment, the chip structure is flip-chip mounted on the upper surface of the pins of the lead frame.

[0030] In an optional embodiment, the chip structure has pads on the surface away from the base island, and the bonding wires are electrically connected to the chip structure through the pads.

[0031] In an optional embodiment, the electromagnetic shielding wire includes multiple single wires, the two ends of which are electrically connected to the upper surface of the grounding metal layer, and the multiple single wires are electrically connected to the grounding pins in sequence through the grounding metal layer and the grounding wire.

[0032] In an optional embodiment, the multiple single-wire bodies are arranged in a grid pattern.

[0033] In an alternative embodiment, the multiple single wires may or may not be in contact at the locations where they form cross nodes.

[0034] In an optional embodiment, the lead frame is a leadless quad flat package lead frame.

[0035] In an alternative embodiment, the ground metal layer is a rectangular ring structure adapted to the leadless quad flat package lead frame.

[0036] In an optional embodiment, the grounding metal layer is a copper grounding metal layer, a gold grounding metal layer, an aluminum grounding metal layer, or a tungsten grounding metal layer.

[0037] In an optional embodiment, an adhesive layer is further included, which is disposed between the base island of the lead frame and the chip structure, the chip structure being bonded to the surface of the base island via the adhesive layer.

[0038] In an optional embodiment, the electromagnetic shielding wires are respectively positioned directly above the corresponding pins, and the projection portion of the electromagnetic shielding wires onto the plane containing the upper surface of the lead frame is located on the upper surface of the pins.

[0039] The advantages of the technical solution in this application are:

[0040] By forming a first stepped groove on the molding compound, and a grounding metal layer on the surface of the first stepped groove, and electrically connecting the grounding metal layer and the grounding pins of the leadframe via grounding wires, electromagnetic shielding wires can be sequentially electrically connected to the grounding pins of the leadframe via the grounding metal layer and grounding wires (all electromagnetic shielding wires are interconnected and grounded), thus forming electromagnetic shielding above the chip structure. This structural design allows the electromagnetic shielding structure within the leadframe packaging structure to be formed by wire bonding (electromagnetic shielding wires). Furthermore, the electromagnetic shielding wires do not need to be directly grounded, significantly reducing the difficulty of wire bonding. Further, a second stepped groove can block the connection between the grounding metal layer and the non-grounded pins of the leadframe, excluding the grounding pins. Simultaneously, when a continuous annular grounding metal layer is formed around the chip structure, the electromagnetic shielding wires form an electromagnetic shielding cover along the annular grounding metal layer, providing electromagnetic shielding on the outer periphery of the chip structure. Combined with the mesh structure formed by the electromagnetic shielding wires above the chip structure, electromagnetic shielding can be achieved on all five sides of the chip structure, resulting in a superior electromagnetic shielding effect for the packaging structure. Attached Figure Description

[0041] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In addition, in the following drawings, the components are not necessarily drawn to scale, and components with similar related characteristics or features may have the same or similar reference numerals.

[0042] Figure 1 This is a top view of a lead frame encapsulation structure with electromagnetic shielding according to an embodiment of this application.

[0043] Figure 2 This is a schematic diagram of the lead frame encapsulation structure with electromagnetic shielding according to an embodiment of this application along A1-A2;

[0044] Figure 3 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 1 ;

[0045] Figure 4 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 2 ;

[0046] Figure 5 for Figure 4 Corresponding top view structural diagram (and Figure 4for Figure 5 (Cross-section view along B1-B2)

[0047] Figure 6 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 3 ;

[0048] Figure 7 for Figure 6 The corresponding top-view structural diagram (except for the electromagnetic shielding wire and the grounding wire, the rest of the structure is blurred, and...) Figure 6 for Figure 7 (Cross-section view along C1-C2)

[0049] Figure 8 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 4 ;

[0050] Figure 9 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 5 ;

[0051] Figure 10 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 6 ;

[0052] Figure 11 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 7 ;

[0053] Figure 12 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 8 ;

[0054] Figure 13 This is a top view of a lead frame encapsulation structure with electromagnetic shielding according to another embodiment of this application (components such as the grounding metal layer are drawn as shown).

[0055] Figure 14 This is a schematic diagram of the lead frame packaging structure with electromagnetic shielding according to another embodiment of this application, viewed from the front.

[0056] The labels for the attached figures are as follows:

[0057] 1. Lead frame; 11. Base island; 12. Grounding pin; 13. Non-grounding pin; 14. Connecting rib; 2. Chip structure; 3. Molding layer; 31. First step groove; 32. Second step groove; 33. First groove; 34. Second groove; 4. Grounding metal layer; 5. Electromagnetic shielding wire; 6. Grounding wire; 7. Adhesive layer; 8. Bonding wire; 100. Frame unit. Detailed Implementation

[0058] To make the technical problems, technical solutions and beneficial effects to be solved by this application clearer, the following describes this application in further detail with reference to the accompanying drawings and embodiments.

[0059] In the description of this application, it should be noted that the use of terms such as "first" and "second" to define objects (such as elements, components, regions, layers, doping types and / or parts) is merely for the purpose of distinguishing different objects and is not necessarily used to describe a specific order or sequence. Unless the context clearly indicates otherwise, it should be understood that such data can be used interchangeably where appropriate.

[0060] In the description of this application, it should be understood that the singular forms “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that when the terms “compose” and / or “comprise” are used in this specification, the presence of the stated feature, integer, step, operation, element, and / or part is established, but the presence or addition of one or more other features, integers, steps, operations, elements, parts, and / or groups is not excluded. Meanwhile, when used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0061] In the description of this application, it should also be noted that when a component is referred to as "on another component," "connected to another component," or "in contact with another component," it can mean not only that a component is directly on, directly connected to, or directly in contact with the other component, but also that an intermediate component can be inserted between the two components. Furthermore, "connection" includes not only fixed connections but also detachable connections or integral connections. Similarly, when an element is referred to as "electrically connected," "electrically contacted," "electrically coupled," or "electrically coupled to" another element, the two elements can be in direct electrical contact or electrical coupling, or they can be in electrical contact or electrical coupling through an intermediate component.

[0062] In the description of this application, it should also be noted that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0063] Furthermore, in the description of this application, spatial relation terms such as "below," "under," "below," "below," "below," "above," "on the upper surface of," "above," etc., can be used to describe the spatial positional relationship between one element or feature shown in the figures and other elements or features. It should be understood that spatial relation terms, in addition to the orientation shown in the figures, also include different orientations of elements or features in use and operation. For example, if an element or feature in the figures is flipped or inverted, an element or feature described as "below" or "below" other elements or features will be oriented "above" other elements or features. Furthermore, elements may also include other orientations (e.g., rotated by an angle or other orientations).

[0064] This application provides a lead frame packaging structure with electromagnetic shielding, in conjunction with reference to [reference needed]. Figures 1-13 ,in Figure 1 This is a top view of a lead frame encapsulation structure with electromagnetic shielding according to an embodiment of this application. Figure 2 This is a schematic diagram of the lead frame encapsulation structure with electromagnetic shielding according to an embodiment of this application along A1-A2; Figure 3 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 1 ; Figure 4 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 2 ; Figure 5 for Figure 4 Corresponding top view structural diagram (and Figure 4 for Figure 5 (Cross-section view along B1-B2) Figure 6 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 3 ; Figure 7 for Figure 6 The corresponding top-view structural diagram (except for the electromagnetic shielding wire and the grounding wire, the rest of the structure is blurred, and...) Figure 6 for Figure 7(Cross-section view along C1-C2) Figure 8 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 4 ; Figure 9 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 5 ; Figure 10 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 6 ; Figure 11 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 7 ; Figure 12 This is a schematic diagram of a method for forming a lead frame packaging structure with electromagnetic shielding in one embodiment of this application. Figure 8 ; Figure 13 This is a top view of a lead frame encapsulation structure with electromagnetic shielding according to another embodiment of this application (components such as the grounding metal layer are drawn as shown). Figure 14 This is a schematic diagram of the lead frame packaging structure with electromagnetic shielding according to another embodiment of this application, viewed from the front. The lead frame packaging structure with electromagnetic shielding includes:

[0065] The lead frame 1 includes a base island 11 and pins disposed outside the base island 11, including a grounded pin 12 and a non-grounded pin 13.

[0066] Chip structure 2 is disposed on the upper surface of base island 11;

[0067] The molding layer 3 is located on the surface of the lead frame 1 and covers the chip structure 2, and exposes the lower surface of the lead frame. The molding layer 3 has a first stepped groove 31 formed on the sidewall near the upper surface of the lead frame 1.

[0068] Grounding metal layer 4 is located on the bottom wall of the first step groove 31, and the grounding metal layer 4 does not directly contact the pins of the lead frame 1.

[0069] Electromagnetic shielding wire 5 is located inside the molding layer 3 and spans across the chip structure 2 on the side away from the lead frame 1. The two ends of the electromagnetic shielding wire 5 are electrically connected to the upper surface of the opposite grounded metal layer 4, respectively.

[0070] Grounding wire 6, with both ends electrically connected to at least one grounding pin 12 of grounding metal layer 4 and lead frame 1 respectively;

[0071] The connection ends of the grounding wire 6 and / or electromagnetic shielding wire 5, which are respectively connected to the grounding metal layer 4, are located on the bottom wall of the first step groove 31. This bottom wall is the bonding surface between the plastic sealing layer 3 and the grounding metal layer 4.

[0072] Existing electromagnetic shielding technology using electromagnetic shielding wires can only be used in substrate-based packages. Because the substrate contains internal wiring, the bonding wires spanning the chip surface can be connected to a single ground signal through these internal circuitry, thus achieving electromagnetic shielding. However, for leadframe-based packages, the leadframe only has pins. These pins are used to transmit various signals between the chip and external circuits, and each pin transmits a different electrical signal. Since the electromagnetic shielding wire only transmits a single ground signal, it is impossible to achieve electromagnetic shielding by creating a cross-chip electromagnetic shielding line by bonding wires to the pins.

[0073] By forming a first stepped groove 31 on the molding layer 3, and a grounding metal layer 4 on the bottom wall of the first stepped groove 31, and electrically connecting the grounding metal layer 4 and the grounding pin 12 of the lead frame 1 through the grounding wire 6, the electromagnetic shielding wire 5 can be electrically connected to the grounding pin 12 of the lead frame 1 in sequence through the grounding metal layer 4 and the grounding wire 6, thus achieving complete grounding of the electromagnetic shielding wire 5 and forming electromagnetic shielding on five sides above and around the chip structure 2. In other words, this structural configuration allows the electromagnetic shielding structure to be formed in the lead frame 1 type of packaging structure by wire bonding (electromagnetic shielding wire 5).

[0074] Please refer to Figure 2 In one embodiment, the electromagnetic shielding wires 5 are respectively straddled above the corresponding pins, and the projection portion of the electromagnetic shielding wires 5 onto the plane of the upper surface of the lead frame 1 is located on the upper surface of the pins.

[0075] Please refer to Figure 2 In one embodiment, the surface of the molding layer 3 further has a second stepped groove 32, which is disposed near the surface of the molding layer 3 near the lead frame 1, and the first stepped groove 31 is located at the bottom of the second stepped groove 32.

[0076] The second step groove 32 is used to prevent the grounding metal layer from directly contacting the pin.

[0077] The second step groove 32 can block the connection between the grounding metal layer and the non-grounded pins 13 of the lead frame 1, except for the grounding pin 12.

[0078] Please refer to Figure 14 In another embodiment, the surface of the molding layer 3 does not have the second step groove 32, and the grounding metal layer and the pin are spaced apart and do not directly contact each other.

[0079] In one embodiment, the first step groove 31 and the second step groove 32 are respectively annular step grooves arranged in a circumferential direction around the chip structure 2;

[0080] The grounding metal layer 4 is a continuous annular connecting ring arranged in a circumferential direction around the chip structure 2.

[0081] By setting a continuous annular grounding metal layer 4 around the chip structure 2, the outer periphery of the chip structure 2 has continuous electromagnetic shielding, thereby giving the packaging structure a better electromagnetic shielding effect.

[0082] In another embodiment, the first step groove 31 includes a plurality of first step grooves 31 arranged circumferentially around the chip structure 2;

[0083] The grounding metal layer 4 has multiple pieces, and the multiple grounding metal layers 4 are correspondingly arranged with multiple first step grooves 31.

[0084] Please refer to Figure 13 In one specific embodiment, the first step groove 31 includes four, and the four first step grooves 31 are respectively located on the four sides of the chip structure 2. The four ground metal layers 4 are arranged circumferentially around the chip structure 2. At this time, the electromagnetic shielding lines 5 that cross each other are electrically connected to each other, so that the multiple electromagnetic shielding lines 5 and the four ground metal layers 4 are connected to the ground pin 12 through at least one grounding line 6.

[0085] In another specific embodiment, the first step groove 31 includes four, and the four first step grooves 31 are respectively located on the four sides of the chip structure 2. The four ground metal layers 4 are arranged circumferentially around the chip structure 2. The electromagnetic shielding lines 5 can be arranged without contact. At this time, at least one of the two ground metal layers 4 connected to the two ends of each electromagnetic shielding line 5 is grounded and connected to the ground pin 12 through the grounding wire 6.

[0086] In one embodiment, the grounding metal layer 4 is located on the bottom surface of the first step groove 31 and is in contact with the side surface of the first step groove 31.

[0087] In one embodiment, neither the side surface of the second step groove 32 nor the bottom surface of the second step groove 32 has a grounding metal layer 4.

[0088] In one embodiment, the horizontal plane of the bottom surface of the second step groove 32 is at least lower than the horizontal plane of the upper surface of the chip structure 2 on the side away from the lead frame 1.

[0089] In one embodiment, the height of the grounding metal layer 4 is less than or equal to the side height of the first step groove 31.

[0090] In one embodiment, the bottom surface of the second step groove 32 is at a level higher than or level with the upper surface of the lead frame 1 on the side of the lead frame 1 closest to the chip structure 2.

[0091] In one embodiment, the horizontal plane of the bottom surface of the first step groove 31 is lower than the horizontal plane of the upper surface of the chip structure 2 on the side away from the lead frame 1.

[0092] In one embodiment, it also includes bonding wires 8, which are located within the molding compound 3;

[0093] The two ends of the bonding wire 8 are electrically connected to the pins of the chip structure 2 and the lead frame 1, respectively.

[0094] In another embodiment, the chip structure 2 is disposed on the upper surface of the pins by flip-chip bonding, in which case there is no need to provide bonding wires 8.

[0095] In one embodiment, a pad is provided on the side surface of the chip structure 2 away from the base island 11, and the bonding wire 8 is electrically connected to the chip structure 2 through the pad.

[0096] In one embodiment, the electromagnetic shielding wire 5 includes multiple single wires, the two ends of which are electrically connected to the grounding metal layer 4, and the multiple single wires are electrically connected to the grounding pin 12 in sequence through the grounding metal layer 4 and the grounding wire 6.

[0097] In one embodiment, multiple single-wire bodies are arranged in a grid pattern.

[0098] In another embodiment, the multiple single-line bodies are arranged in a parallel line structure.

[0099] In one embodiment, multiple single wires may or may not be in contact at the locations where they form cross nodes.

[0100] In one embodiment, the lead frame 1 is a leadless quad flat package lead frame (QFN lead frame).

[0101] In another embodiment, the lead frame 1 may also be a lead frame with single-sided or double-sided pins.

[0102] In one specific embodiment, a single-sided pin has multiple pins spaced apart.

[0103] In one embodiment, the ground metal layer 4 is a rectangular ring structure adapted to the lead frame of a leadless quad flat package.

[0104] In one embodiment, the grounding metal layer 4 is a copper grounding metal layer, a gold grounding metal layer, an aluminum grounding metal layer, or a tungsten grounding metal layer.

[0105] In one embodiment, an adhesive layer 7 is also included, through which the chip structure 2 is bonded to the upper surface of the base island 11.

[0106] Please refer to Figures 2-14 This application also provides a method for fabricating a lead frame packaging structure with electromagnetic shielding, comprising:

[0107] S100. Please refer to... Figure 3 The present invention provides a lead frame 1 and a chip structure 2. The lead frame 1 includes multiple frame units 100, and adjacent frame units 100 are connected by connecting ribs 14. Each frame unit 100 includes a base island 11 and pins disposed on the outside of the base island 11. The chip structure 2 is disposed on the upper surface of the base island 11.

[0108] S200. Please refer to... Figure 4 and Figure 5 This forms a grounding wire 6, with both ends of the grounding wire 6 located on the same grounding pin 12 surface of the lead frame 1, and one end located on the side of the grounding pin 12 near the connecting rib 14.

[0109] S300. Please refer to... Figure 6 and Figure 7 An electromagnetic shielding line 5 is formed, which is laid across the chip structure 2 on the side away from the lead frame 1, and the two ends of the electromagnetic shielding line 5 are respectively located on the upper surface of the grounded pin and the upper surface of the non-grounded pin of the lead frame 1.

[0110] In one embodiment, when the chip structure 2 is disposed on the upper surface of the base island 11 by bonding wire 8, the bonding wire 8 is further formed before the electromagnetic shielding wire 5 is formed. The two ends of the bonding wire 8 are electrically connected to the pads of the chip structure 2 and the pins of the lead frame 1, respectively.

[0111] In another embodiment, the chip structure 2 is disposed on the upper surface of the pin by flip-chip bonding, in which case the bonding wire 8 is not required.

[0112] S400. Please refer to... Figure 8 A molding layer 3 is formed, which is located on the surface of the lead frame 1 and covers the chip structure 2, electromagnetic shielding line 5, and grounding line 6.

[0113] In one embodiment, when the chip structure 2 is disposed on the upper surface of the base island 11, the bonding wire 8 is located within the molding layer 3.

[0114] S500. Please refer to... Figure 9 The first groove 33 is formed by a single cut. The first groove 33 is located on the side of the plastic encapsulation layer 3 near the lead frame 1. The bottom wall of the first groove 33 exposes the electromagnetic shielding wire 5 and the grounding wire 6. During the single cut, the connecting rib 14 of the lead frame 1, part of the electromagnetic shielding wire 5, part of the grounding wire 6 and part of the pins of the lead frame 1 are cut off.

[0115] The cutting width during a single cut is greater than the width of the connecting rib 14, and the cut extends to the pipe foot position.

[0116] In one embodiment, the first groove 33 is formed by a single cut using a cutting tool.

[0117] S600. Please refer to... Figure 10 A grounding metal layer 4 is formed on the inner wall of the first groove 33, and the surface of the grounding metal layer 4 is electrically connected to the electromagnetic shielding wire 5 and / or the grounding wire 6.

[0118] In one embodiment, a grounding metal layer 4 is formed on the inner wall of the first groove 33 by magnetron sputtering.

[0119] In one embodiment, when the grounding metal layer 4 is formed on the inner wall of the first groove 33, the grounding metal layer 4 does not completely fill the first groove 33.

[0120] In another embodiment, when a grounding metal layer 4 is formed on the inner wall of the first groove 33, the grounding metal layer 4 fills the first groove 33.

[0121] S700. Please refer to... Figure 11 A second groove 34 is formed by using a cutting tool to make secondary cuts on the pin, the plastic encapsulation layer 3, and the grounding metal layer 4. The second groove 34 is located on the side of the plastic encapsulation layer 3 closer to the lead frame 1 and is closer to the lead frame 1 than the first groove 33. The width of the second groove 34 is greater than or equal to the width of the first groove 33. When the width of the second groove 34 is equal to the width of the first groove 33, the electromagnetic shielding layer 4 on the side of the pin and part of the electromagnetic shielding layer 4 on the side wall of the plastic encapsulation layer 3 near the upper surface of the pin are cut off during the secondary cut. When the width of the second groove 34 is greater than the width of the first groove 33, in addition to cutting off the electromagnetic shielding layer 4 on the side of the pin and part of the electromagnetic shielding layer 4 on the side wall of the plastic encapsulation layer 3 near the upper surface of the pin, part of the pin and / or part of the plastic encapsulation layer 3 of the lead frame 1 are also cut off during the secondary cut.

[0122] After the secondary cutting process, the bottom wall of the first groove 33 forms the bottom surface of the first stepped groove 31, the side wall of the first groove 33 forms the side surface of the first stepped groove 31, the bottom wall of the second groove 34 forms the bottom surface of the second stepped groove 32, and the side wall of the second groove 34 forms the side surface of the second stepped groove 32.

[0123] The cutting width during the secondary cutting is greater than or equal to the width of the first groove 33, and the cutting thickness during the secondary cutting is greater than the thickness of the pin, so that the grounding metal layer 4 is not directly connected to the pin.

[0124] Please refer to Figure 14 In another embodiment, the cutting width during the secondary cutting can also be equal to the width of the first groove 33 (without the second groove 34), cutting off a portion of the grounding metal layer 4 on the sidewall of the first groove 33 and near the pin position, so that the grounding metal layer 4 is not directly electrically connected to the pin.

[0125] S800. Please refer to... Figure 12The bottom of the first groove 33 is cut three times to cut the plastic encapsulation layer 3 and the grounding metal layer 4, forming a single electromagnetically shielded lead frame package structure, which is the electromagnetically shielded lead frame package structure described above.

[0126] The cutting width during the three cuts is less than the width of the first groove 33, so that the grounding metal layer 4 on the surface of the first groove 33 is not completely cut off.

[0127] It should be noted that, where there is no conflict, the features in the different embodiments of this application described above can be combined with each other. Furthermore, in each of the above embodiments, the focus is on describing the differences from other embodiments; other specific descriptions of the same / similar parts between the embodiments can be referred to (or referenced) interchangeably. In addition, descriptions of well-known components and technologies have been omitted in the above description to avoid unnecessarily obscuring the concepts of this application.

[0128] Although this application has been disclosed above with reference to preferred embodiments, it is not intended to limit this application. Any person skilled in the art can make possible changes and modifications to the technical solutions of this application by utilizing the methods and techniques disclosed above without departing from the spirit and scope of this application. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall fall within the protection scope of the technical solutions of this application.

Claims

1. A leadframe package structure with electromagnetic shielding, characterized by, include: A lead frame, the lead frame including a base island and pins disposed outside the base island, the pins including grounded pins and non-grounded pins; A chip structure, wherein the chip structure is disposed on the upper surface of the base island; A molding compound is located on the surface of the lead frame and covers the chip structure, and exposes the lower surface of the lead frame. The molding compound has a first stepped groove on the sidewall near the upper surface of the lead frame. A grounding metal layer is located on the bottom wall of the groove of the first step, and the grounding metal layer is not in direct contact with the pin. An electromagnetic shielding wire is located within the molding compound and spans across the chip structure on the side away from the lead frame, and the ends of the electromagnetic shielding wire are electrically connected to the upper surface of the opposite ground metal layer. A grounding wire, the two ends of which are electrically connected to the surface of the grounding metal layer and at least one grounding pin of the lead frame, respectively; The connection ends of the grounding wire and the electromagnetic shielding wire, which are respectively connected to the grounding metal layer, are located on the bottom wall of the first step groove.

2. The leadframe package structure with electromagnetic shielding of claim 1, wherein, The molding layer has a second stepped groove on the surface near the lead frame, and the first stepped groove is located at the bottom of the second stepped groove. The second stepped groove is used to prevent the grounding metal layer from directly contacting the pin.

3. The lead frame packaging structure with electromagnetic shielding as described in claim 2, characterized in that, The first step groove and the second step groove are respectively annular step grooves arranged in a circumferential direction around the chip structure.

4. The lead frame packaging structure with electromagnetic shielding as described in claim 2, characterized in that, The horizontal plane at which the bottom surface of the second step groove is located is at least lower than the horizontal plane at which the upper surface of the chip structure on the side away from the lead frame is located.

5. The lead frame packaging structure with electromagnetic shielding as described in claim 2, characterized in that, The bottom surface of the second step groove is at a horizontal level that is higher than or level with the upper surface of the lead frame pins on the side closest to the chip structure.

6. The lead frame packaging structure with electromagnetic shielding as described in claim 1, characterized in that, The grounding metal layer is a continuous annular connecting ring arranged in a circumferential direction around the chip structure.

7. The lead frame packaging structure with electromagnetic shielding as described in claim 1, characterized in that, The first step groove includes multiple first step grooves, which are arranged circumferentially around the chip structure; The grounding metal layer has multiple pieces, and the multiple pieces of the grounding metal layer are correspondingly arranged with multiple first step grooves.

8. The lead frame packaging structure with electromagnetic shielding as described in claim 1, characterized in that, The grounding metal layer is located on the bottom surface of the first step groove and at least part of the side surface of the first step groove.

9. The lead frame packaging structure with electromagnetic shielding as described in claim 1, characterized in that, The height of the grounding metal layer is less than or equal to the side height of the first step groove.

10. The lead frame packaging structure with electromagnetic shielding as described in claim 1, characterized in that, It also includes bonding wires, which are located within the molding layer; The two ends of the bonding wire are electrically connected to the pads on the surface of the chip structure and the pins of the lead frame, respectively.

11. The lead frame packaging structure with electromagnetic shielding as described in claim 1, characterized in that, The chip structure is flip-chip mounted on the upper surface of the pins of the lead frame.

12. The lead frame packaging structure with electromagnetic shielding as described in claim 1, characterized in that, The horizontal plane of the bottom surface of the first step groove is lower than the horizontal plane of the upper surface of the chip structure on the side away from the lead frame.

13. The lead frame packaging structure with electromagnetic shielding as described in claim 1, characterized in that, The electromagnetic shielding wire comprises multiple single wires, the two ends of which are electrically connected to the upper surface of the grounding metal layer. The multiple single wires, the grounding metal layer, the grounding wire, and the grounding pin are all grounded.

14. The lead frame packaging structure with electromagnetic shielding as described in claim 13, characterized in that, Multiple single-line bodies are arranged in a grid pattern; Multiple single wires may or may not make contact at the points where they form intersections.

15. The lead frame packaging structure with electromagnetic shielding as described in claim 1, characterized in that, The grounding metal layer is a rectangular annular connecting ring.

16. The lead frame packaging structure with electromagnetic shielding as described in claim 1, characterized in that, The grounding metal layer is a copper grounding metal layer, a gold grounding metal layer, an aluminum grounding metal layer, or a tungsten grounding metal layer.

17. The lead frame packaging structure with electromagnetic shielding as described in claim 1, characterized in that, The electromagnetic shielding wires are respectively straddled above the corresponding pins, and the projection of the electromagnetic shielding wires onto the plane of the upper surface of the lead frame is located on the upper surface of the pins.

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