Sensor packaging structure with EMI shielding shell and preparation method thereof

Abstract

The invention relates to the technical field of shielding packaging, and discloses a sensor packaging structure with an EMI shielding shell and a preparation method thereof, and the sensor packaging structure comprises a substrate, a chip assembly, a shielding shell and a gold wire. A grounding bonding pad is arranged on one side of the substrate; the chip assembly is arranged on one side of the substrate, the chip assembly is electrically connected with the substrate, and the chip assembly and the grounding bonding pad are distributed at intervals; the shielding shell is arranged on one side of the substrate, a sealing cavity is defined by the shielding shell and the substrate, the chip assembly is arranged in the sealing cavity, and the outer surface of the shielding shell is coated with a plating layer; one end of the gold wire is in bonding connection with the grounding bonding pad, the gold wire penetrates through the shielding shell, and the other end of the gold wire is electrically connected with the plating layer. One end of the gold wire is directly and firmly bonded on the grounding bonding pad, so that reliable intermetallic connection is formed between the gold wire and the grounding bonding pad, the other end of the gold wire serving as a key conductive interface has oxidation resistance, reliable connection between the gold wire and the plating layer is guaranteed, and the risk of EMI shielding failure of the sensor is avoided.

Description

Technical Field

[0001] This invention relates to the field of shielding and packaging technology, and in particular to a sensor packaging structure with an EMI shielding shell and its preparation method. Background Technology

[0002] Currently, electromagnetic interference (EMI) refers to the phenomenon of electronic components being interfered with by external electromagnetic waves. EMI shielding typically uses metallic materials or conductive coatings to isolate or reduce the interference from the external environment.

[0003] For example, Chinese patent application CN115172352A discloses a surface-mount multi-axis sensor structure and its fabrication method. The structure includes a first substrate and a first encapsulation structure. A circuit unit is provided on the first surface of the first substrate. The circuit unit includes at least a sensor unit, and the sensor unit includes at least a multi-axis sensor. A protective film covers the multi-axis sensor. The circuit unit and the protective film are encapsulated to form the first encapsulation structure. A sputtering layer is formed on the outer surface of the first substrate where the circuit unit is mounted, corresponding to the surface of the first encapsulation structure, using a metal sputtering process. This sputtering layer is partially grounded to achieve EMI shielding protection.

[0004] The current grounding method for the metal sputtered layer of sensors generally involves setting copper pads on the substrate, and then sputtering the sputtered layer onto the surface of the housing to form a sputtered layer, thus electrically connecting the sputtered layer to the copper pads. However, the process interruption between the sputtering process on the housing surface and the previous process is too long, and the copper pads are easily oxidized when exposed to air. This results in poor reliability of the connection between the sputtered layer and the copper pads, which leads to the risk of EMI shielding failure in the sensor. Summary of the Invention

[0005] The technical problem to be solved by this invention is that the process interruption between the sputtering process on the housing surface and the previous process is too long, the copper pads are exposed to the air and are prone to oxidation, the connection between the sputtered layer and the copper pads is unreliable, and the sensor is at risk of EMI shielding failure.

[0006] To address the aforementioned technical problems, this invention provides a technical solution for a sensor packaging structure with an EMI shielding shell: Sensor packaging structures with EMI shielding shells include: A substrate, wherein a grounding pad is provided on one side of the substrate; A chip assembly is disposed on one side of the substrate, the chip assembly is electrically connected to the substrate, and the chip assembly is spaced apart from the ground pad; A shielding shell is disposed on one side of the substrate, the shielding shell and the substrate forming a sealed cavity, the chip assembly is disposed in the sealed cavity, and the outer surface of the shielding shell is covered with a plating layer; A gold wire, one end of which is bonded to the grounding pad, passes through the shielding shell, and the other end of which is electrically connected to the plating layer.

[0007] Furthermore, the gold wire includes a horizontal segment, which is arranged parallel to and spaced apart from the substrate, and the horizontal segment extends through the shielding shell along its wall thickness direction.

[0008] Furthermore, the gold wire is an L-shaped gold wire, which includes a vertical section connected to the horizontal section, and the vertical section is welded to the grounding pad.

[0009] Furthermore, an insulating adhesive is provided between the substrate and the shielding shell, the insulating adhesive is distributed around the sealing cavity, and the insulating adhesive is filled between the grounding pad and the gold wire to support the gold wire.

[0010] Furthermore, the insulating adhesive has a protrusion that covers the outside of the gold wire, and the shielding shell has a groove corresponding to the gold wire. The protrusion is fitted into the groove and connected to the inner wall of the groove.

[0011] Furthermore, the other end of the gold wire protrudes or is flush with the outer surface of the shielding shell.

[0012] Furthermore, the cross-sectional diameter of the other end of the gold wire is D, which satisfies: D≥20μm.

[0013] Furthermore, the shielding shell is a plastic shell, and the coating is deposited on the outer surface of the shielding shell by sputtering.

[0014] Furthermore, at least two grounding pads are provided, and the at least two grounding pads are spaced apart on the substrate, with each grounding pad being bonded to one of the gold wires.

[0015] To address the aforementioned technical problems, this invention provides a technical solution for fabricating a sensor packaging structure with an EMI shielding shell: A method for fabricating a sensor packaging structure with an EMI shielding shell includes the following steps: S1. Mount chip components on the entire substrate, make electrical connections between chip components and between chip components and the substrate, and solder gold wires between the grounding pads of two adjacent sensor units. S2. Apply insulating adhesive to the outer periphery of the chip assembly on the entire substrate, so that the insulating adhesive fills between the grounding pad and the gold wire, and covers the outside of the gold wire through its protrusion. S3. Cover the entire substrate with a shielding shell, and then bond the entire substrate and the shielding shell together with insulating adhesive to form a single-piece sensor. S4. Cut the whole sensor into pieces along the set dividing line, so that the gold wire is cut off and exposed on the outer surface of the shielding shell, and obtain multiple sensor unit semi-finished products. S5. Sputter deposition is performed on the shielding shell of the sensor unit semi-finished product to form a coating. The coating is connected to the cut end face of the gold wire to obtain the finished sensor unit.

[0016] Compared with the prior art, the sensor packaging structure with EMI shielding shell and its preparation method of the present invention have the following advantages: The sensor packaging structure with EMI shielding shell adopts a design of substrate, chip assembly, shielding shell and gold wire. A grounding pad is provided on one side of the substrate, the chip assembly is disposed on one side of the substrate and electrically connected to the substrate, and the chip assembly and the grounding pad are distributed at intervals; the shielding shell is disposed on one side of the substrate and forms a sealed cavity with the substrate, the outer surface of the shielding shell is covered with a plating layer, one end of the gold wire is bonded to the grounding pad, and the gold wire passes through the shielding shell and its other end is electrically connected to the plating layer.

[0017] Specifically, by extending a gold wire through the shielding shell, the connection sequence between the sputtered layer of the shielding shell and the original grounding pad was changed. A grounding path was formed from the grounding pad, the gold wire, to the shielding shell plating, thus reconstructing the grounding connection method of the shielding shell plating. Before installing the shielding shell, a mature wire bonding process was used to directly and firmly bond one end of the gold wire to the grounding pad. This not only breaks the thin oxide layer on the surface of the pad but also forms a reliable metal-to-metal connection between the gold wire and the grounding pad.

[0018] Utilizing gold wire bonding, the grounding pad is only briefly exposed before bonding. Once the gold wire bonding is complete, its electrical connection function is achieved and "leaded out" by the gold wire. Although the copper surface of the grounding pad may still oxidize, regardless of the length of subsequent process interruptions, the gold wire itself and the electrical connection point between the gold wire and the grounding pad possess an extremely oxidation-resistant "golden surface." More importantly, the other end of the gold wire, as a critical conductive interface, is oxidation-resistant, ensuring a reliable connection between the gold wire and the plating layer. By using the gold wire as an intermediate conductor, the risk path that could lead to copper oxidation affecting connection reliability is cut off, thereby avoiding the risk of EMI shielding failure in the sensor. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the sensor packaging structure with an EMI shielding shell (without the shielding shell) according to an embodiment of the present invention; Figure 2 This is a cross-sectional schematic diagram of the sensor packaging structure with an EMI shielding shell according to an embodiment of the present invention; Figure 3This is an assembly diagram of step S1 in the preparation method of the sensor packaging structure with EMI shielding shell according to an embodiment of the present invention; Figure 4 This is an assembly diagram of step S2 in the preparation method of the sensor packaging structure with EMI shielding shell according to an embodiment of the present invention; Figure 5 This is an assembly diagram of step S3 in the preparation method of the sensor packaging structure with EMI shielding shell according to an embodiment of the present invention; Figure 6 This is an assembly diagram of step S4 in the preparation method of the sensor packaging structure with EMI shielding shell according to an embodiment of the present invention; Figure 7 This is an assembly diagram of step S5 in the preparation method of the sensor packaging structure with EMI shielding shell according to an embodiment of the present invention; In the diagram: 1. Substrate; 11. Grounding pad; 2. Chip assembly; 3. Shielding shell; 30. Sealing cavity; 31. Plating layer; 32. Groove; 4. Gold wire; 41. Horizontal section; 42. Vertical section; 5. Insulating adhesive; 50. Protrusion; 1a. Whole substrate; 2a. Whole shielding shell; 3a. Whole sensor; 4a. Sensor unit semi-finished product; 5a. Sensor unit finished product. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise" used to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to 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 of this invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] like Figure 1 , Figure 2 As shown, an embodiment of the present invention provides a sensor packaging structure with an EMI shielding shell, comprising a substrate 1, a chip assembly 2, a shielding shell 3, and a gold wire 4. A grounding pad 11 is provided on one side of the substrate 1; the chip assembly 2 is disposed on one side of the substrate 1, electrically connected to the substrate 1, and spaced apart from the grounding pad 11; the shielding shell 3 is disposed on one side of the substrate 1, forming a sealed cavity 30 with the substrate 1, and the chip assembly 2 is disposed within the sealed cavity 30; a plating layer 31 is applied to the outer surface of the shielding shell 3; one end of the gold wire 4 is bonded to the grounding pad 11, the gold wire 4 passes through the shielding shell 3, and the other end of the gold wire 4 is electrically connected to the plating layer 31.

[0025] The sensor packaging structure with EMI shielding adopts a design of substrate 1, chip assembly 2, shielding shell 3 and gold wire 4. A grounding pad 11 is provided on one side of substrate 1. Chip assembly 2 is located on one side of substrate 1 and electrically connected to substrate 1. Chip assembly 2 and grounding pad 11 are spaced apart. Shielding shell 3 is located on one side of substrate 1 and forms a sealed cavity 30 with substrate 1. The outer surface of shielding shell 3 is covered with a plating layer 31. One end of gold wire 4 is bonded to grounding pad 11 and the other end of gold wire 4 passes through shielding shell 3 and is electrically connected to plating layer 31.

[0026] Specifically, by extending a gold wire 4 through the shielding shell 3, the connection sequence between the plating 31 of the shielding shell 3 and the original grounding pad 11 is changed. A grounding path is formed from the grounding pad 11, the gold wire 4, to the plating 31 of the shielding shell 3, thereby reconstructing the grounding connection method of the plating 31 of the shielding shell 3. Before installing the shielding shell 3, a mature wire bonding process is used to directly and firmly bond one end of the gold wire 4 to the grounding pad 11. This not only breaks the thin oxide layer on the surface of the pad but also enables the gold wire 4 to form a reliable intermetallic connection with the grounding pad 11.

[0027] Employing a gold wire bonding process, the grounding pad 11 is only briefly exposed before bonding. Once the gold wire bonding is complete, its electrical connection function is achieved and "leaded out" by the gold wire. Although the copper surface of the grounding pad 11 may still oxidize, regardless of the length of subsequent process interruptions, the gold wire itself and the electrical connection point between the gold wire and the grounding pad 11 possess a highly oxidation-resistant "gold surface." More importantly, the other end of the gold wire, as a critical conductive interface, has oxidation resistance, ensuring a reliable connection between the gold wire and the plating layer 31. Through the gold wire as an intermediate conductor, the risk path that could lead to copper oxidation affecting connection reliability is cut off, thereby avoiding the risk of EMI shielding failure in the sensor.

[0028] In this embodiment, as Figure 2 As shown, the gold wire 4 is an L-shaped gold wire, including a horizontal segment 41. The horizontal segment 41 is arranged parallel to and spaced apart from the substrate 1, and extends through the shielding shell 3 along its wall thickness direction. The gold wire 4 also includes a vertical segment 42 connected to the horizontal segment 41, which is welded to the grounding pad 11. The gold wire 4 is designed in an L-shape. The vertical segment 42 is responsible for bonding with the grounding pad of the substrate 1 in the vertical direction, while the horizontal segment 41 is responsible for penetrating the shielding shell 3 in the planar direction and achieving lateral lead-out and connection, thereby completing the spatial transition from the plane of the substrate 1 to the outer wall of the shielding shell 3, ensuring the reliability of the mechanical structure and electrical connection.

[0029] As a further preferred embodiment, an insulating adhesive 5 is provided between the substrate 1 and the shielding shell 3. The insulating adhesive 5 is distributed around the sealed cavity 30 and fills the space between the grounding pad 11 and the gold wire 4 to support the gold wire 4. As the main sealing material, the insulating adhesive 5 firmly bonds the shielding shell 3 to the substrate 1, forming an airtight sealed cavity 30, protecting the internal chip assembly 2 from moisture, dust, and chemical corrosion, thereby ensuring the operational stability of the sensor packaging structure.

[0030] Furthermore, the insulating adhesive 5 has a protrusion 50 that covers the outer side of the gold wire 4. The shielding shell 3 has a groove 32 corresponding to the gold wire 4. The protrusion 50 is fitted into the groove 32 and connected to the inner wall of the groove 32. The protrusion 50 of the insulating adhesive 5 completely wraps around and seals the part of the gold wire 4 that is embedded through the shielding shell 3, which can effectively support the gold wire 4 to prevent it from deforming or shifting. It provides additional fixation and stress buffering, protects the bonding point between the most vulnerable gold wire 4 and the grounding pad 11, and at the same time prevents the risk of external moisture or contaminants entering the cavity along the microscopic gaps between the gold wire 4 and the hole wall of the shielding shell 3.

[0031] In this embodiment, the other end of the gold wire 4 protrudes or is flush with the outer surface of the shielding shell 3. If the end of the gold wire 4 is flush with the outer surface of the shielding shell 3, it can be integrated with the plating layer 31 using a sputtering deposition process to form a smooth and flat surface, which can be used for subsequent assembly or to meet specific appearance requirements. If the end of the gold wire 4 protrudes from the outer surface of the shielding shell 3, it is easy to confirm that the gold wire 4 has been correctly threaded through and can be used for connection, providing a certain length tolerance for the connection of the plating layer 31.

[0032] In addition, the cross-sectional diameter of the other end of the gold wire 4 is D, which satisfies: D≥20μm, so that a sufficient connection area is formed between the end of the gold wire 4 and the shielding shell 3, ensuring the reliability of the electrical connection between the two. The shielding shell 3 is a plastic shell, and the plating layer 31 is deposited on the outer surface of the shielding shell 3 by sputtering. At least two grounding pads 11 are provided, and the at least two grounding pads 11 are distributed at intervals on the substrate 1, and each grounding pad 11 is bonded to a gold wire 4.

[0033] A method for fabricating a sensor packaging structure with an EMI shielding shell includes the following steps: S1. Mount the chip assembly 2 on the entire substrate 1a, such as... Figure 3 As shown, electrical connections are made between chip components 2 and between chip components 2 and substrate 1, and gold wires 4 are soldered between the grounding pads 11 of two adjacent sensor units. Specifically, electrical connections between chip components 2 and between chip components 2 and substrate 1 are made by wire bonding, and gold wires 4 are soldered between the grounding pads 11 of two adjacent sensor units to prepare for the subsequent assembly of the shielding shell 3 and the electrical connection process of the plating layer 31.

[0034] S2, such as Figure 4 As shown, insulating adhesive 5 is applied to the outer periphery of the chip assembly 2 on the entire substrate 1a, filling the space between the grounding pad 11 and the gold wire 4, and covering the outer side of the gold wire 4 through its protrusion 50. The insulating adhesive 5 can firmly bond the shielding shell 3 to the substrate 1, and the protrusion 50 effectively supports the gold wire 4 to prevent deformation or displacement, providing additional fixation and stress buffering, and protecting the most vulnerable bonding point between the gold wire 4 and the grounding pad 11.

[0035] S3. Cover the entire substrate 1a with the entire shielding shell 2a, such as... Figure 5 As shown, a monolithic sensor 3a is formed by bonding and fixing a whole substrate 1a and a whole shielding shell 2a together with insulating adhesive 5. The whole shielding shell 2a has multiple grooves 32, and the protrusions 50 of the insulating adhesive 5 fit into the grooves 32. The grounding pads 11 of two adjacent sensor units are connected together by gold wires 4.

[0036] S4, such as Figure 6As shown, the monolithic sensor 3a is cut into sections along a defined boundary line, so that the gold wires 4 are cut off and exposed on the outer surface of the shielding shell 3, resulting in multiple sensor unit semi-finished products 4a. The gold wires 4 between the grounding pads 11 of two adjacent sensor units are cut off, so that the end faces of the gold wires 4 are flush with the outer surface of the shielding shell 3, in preparation for subsequent sputtering deposition of the coating 31.

[0037] S5, such as Figure 7 As shown, a coating 31 is formed by sputtering deposition on the shielding shell 3 of the sensor unit semi-finished product 4a. The coating 31 is connected to the cut end face of the gold wire 4 to obtain the finished sensor unit 5a. At this time, the coating 31 completely covers the entire outer surface of the sensor and forms a reliable electrical connection with the grounding pad 11 of the substrate 1 through the gold wire 4, ensuring the stability of the sensor's EMI shielding performance.

[0038] The method for preparing the sensor packaging structure with EMI shielding shell in this embodiment of the invention is the same as the specific embodiments of the method for preparing the sensor packaging structure with EMI shielding shell in the embodiments of this invention, and will not be repeated here.

[0039] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A sensor packaging structure with an EMI shielding shell, characterized in that, include: A substrate (1) is provided with a grounding pad (11) on one side of the substrate (1). A chip assembly (2) is disposed on one side of the substrate (1), the chip assembly (2) is electrically connected to the substrate (1), and the chip assembly (2) is spaced apart from the ground pad (11); A shielding shell (3) is disposed on one side of the substrate (1). The shielding shell (3) and the substrate (1) form a sealed cavity (30). The chip assembly (2) is disposed in the sealed cavity (30). The outer surface of the shielding shell (3) is covered with a plating layer (31). A gold wire (4) is bonded to the grounding pad (11) at one end and passes through the shielding shell (3) at the other end.

2. The sensor packaging structure with an EMI shielding shell according to claim 1, characterized in that, The gold wire (4) includes a horizontal segment (41), which is arranged parallel to and spaced apart from the substrate (1). The horizontal segment (41) is disposed through the shielding shell (3) along the wall thickness direction.

3. The sensor packaging structure with an EMI shielding shell according to claim 2, characterized in that, The gold wire (4) is an L-shaped gold wire, which includes a vertical section (42) connected to the horizontal section (41), and the vertical section (42) is welded to the grounding pad (11).

4. The sensor packaging structure with an EMI shielding shell according to any one of claims 1 to 3, characterized in that, An insulating adhesive (5) is provided between the substrate (1) and the shielding shell (3). The insulating adhesive (5) is distributed around the sealing cavity (30). The insulating adhesive (5) fills the space between the grounding pad (11) and the gold wire (4) to support the gold wire (4).

5. The sensor packaging structure with an EMI shielding shell according to claim 4, characterized in that, The insulating adhesive (5) has a protrusion (50) which covers the outside of the gold wire (4). The shielding shell (3) has a groove (32) corresponding to the gold wire (4). The protrusion (50) is fitted into the groove (32) and connected to the inner wall of the groove (32).

6. The sensor packaging structure with an EMI shielding shell according to any one of claims 1 to 3, characterized in that, The other end of the gold wire (4) protrudes or is flush with the outer surface of the shielding shell (3).

7. The sensor packaging structure with an EMI shielding shell according to claim 6, characterized in that, The diameter of the cross section at the other end of the gold wire (4) is D, which satisfies: D≥20μm.

8. The sensor packaging structure with an EMI shielding shell according to claim 1, characterized in that, The shielding shell (3) is a plastic shell, and the coating (31) is deposited on the outer surface of the shielding shell (3) by sputtering.

9. The sensor packaging structure with an EMI shielding shell according to claim 1, characterized in that, At least two grounding pads (11) are provided, and at least two grounding pads (11) are spaced apart on the substrate (1). Each grounding pad (11) is bonded to a gold wire (4).

10. A method for preparing a sensor packaging structure with an EMI shielding shell as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Attach chip components (2) to the whole substrate (1a), make electrical connections between chip components (2) and between chip components (2) and substrate (1), and solder gold wires (4) between the ground pads (11) of two adjacent sensor units. S2. Apply insulating adhesive (5) to the outer periphery of the chip assembly (2) on the entire substrate (1a) so that the insulating adhesive (5) fills between the grounding pad (11) and the gold wire (4) and covers the outside of the gold wire (4) through its protrusion (50). S3. Cover the entire substrate (1a) with the entire shielding shell (2a), and bond and fix the entire substrate (1a) and the entire shielding shell (2a) with insulating glue (5) to form an integral sensor (3a). S4. Cut the whole sensor (3a) into pieces along the set dividing line so that the gold wire (4) is cut off and exposed on the outer surface of the shielding shell (3) to obtain multiple sensor unit semi-finished products (4a). S5. Sputtering deposition is performed on the shielding shell (3) of the sensor unit semi-finished product (4a) to form a coating (31). The coating (31) is connected to the cut end face of the gold wire (4) to obtain the sensor unit finished product (5a).

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