CN115411175A

CN115411175A - Magnetic assembly and packaging method thereof

Info

Publication number: CN115411175A
Application number: CN202110578524.9A
Authority: CN
Inventors: 何世坤; 赵京升; 宋广明
Original assignee: Hikstor Technology Co Ltd
Current assignee: Hikstor Technology Co Ltd
Priority date: 2021-05-26
Filing date: 2021-05-26
Publication date: 2022-11-29

Abstract

The application discloses a magnetic assembly which comprises a substrate, substrate pins, a chip, a circuit board and a shielding component, wherein the chip is positioned on the upper surface of the substrate; the circuit board is provided with circuits and welding spots positioned at two ends of the circuits, the chip is connected with the substrate pins through the welding spots and the circuits, and the shielding component provides a magnetic shielding structure for the chip. Therefore, the chip and the substrate pins of the magnetic assembly are connected with the circuit through the welding spots, namely the chip and the substrate pins are connected through the circuit board, the packaging height of the magnetic assembly can be reduced due to the thin thickness of the circuit board, and the gold wire is replaced by the circuit board, so that the situation that the gold wire is in contact with the shielding component and short circuit occurs is effectively avoided, and the reliability of the magnetic assembly is improved; in addition, the shielding component can be attached to the circuit board, and the reliability of subsequent plastic packaging can be ensured. In addition, the application also provides a packaging method of the magnetic component with the advantages.

Description

Magnetic assembly and packaging method thereof

Technical Field

The present disclosure relates to the field of chip packaging technologies, and in particular, to a magnetic component and a packaging method thereof.

Background

Magnetic materials and magnetoresistive elements are widely used in the field of memories and sensors, for example, magnetic Random Access Memories (MRAMs) write by magnetization switching of a free layer in a Magnetic tunnel junction. In order to avoid adverse effects of an external magnetic field on the performance of the magnetic component, it is important to magnetically shield and encapsulate the magnetic component.

At present, a schematic structural diagram of a magnetic component after magnetic shielding packaging is shown in fig. 1, a chip 2 is fixed on a substrate 1, the chip 2 is connected with substrate pins 3 through gold wires 6, and as a magnetic shielding layer 5 is conductive, the gold wires 6 are in contact with the magnetic shielding layer 5 to cause short circuit of the chip 2, so that a sufficient distance between the magnetic shielding layer 5 and the substrate 1 needs to be ensured, and the height of the magnetic component is large; the gold wire 6 and the magnetic shielding layer 5 are designed to be less than the package 4 made of the plastic sealing material during plastic sealing, which reduces the reliability of the magnetic device.

Therefore, how to solve the above technical problems should be a great concern to those skilled in the art.

Disclosure of Invention

The present disclosure is directed to a magnetic device and a method for packaging the same, so as to reduce a packaging height of the magnetic device and improve reliability of the magnetic device.

In order to solve the technical problem, the present application provides a magnetic assembly, which includes a substrate, substrate pins, a chip located on an upper surface of the substrate, a circuit board, and a shielding component;

the circuit board is provided with circuits and welding spots positioned at two ends of the circuits, the chip is connected with the substrate pins through the welding spots and the circuits, and the shielding component provides a magnetic shielding structure for the chip.

Optionally, the shielding component is a shielding frame disposed above the chip and connected to the substrate;

wherein the line comprises a non-direct line; the circuit board is provided with a magnetic shielding loop notch penetrating through the thickness, and the side wall of the shielding frame is connected with the substrate through the magnetic shielding loop notch so as to form the magnetic shielding structure for the chip.

Optionally, the shielding frame and the substrate are packaged in an SOP packaging form.

Optionally, the shielding frame is in an inverted U shape, and a sidewall of the inverted U-shaped shielding frame is connected to the substrate.

Optionally, the substrate is provided with a positioning mark for aligning the shielding frame.

Optionally, the circuit board is a flexible circuit film.

Optionally, the base plate includes a non-magnetic shielding base plate main body and a magnetic shielding backing plate located on an upper surface of the non-magnetic shielding base plate main body.

Optionally, the material of the shielding frame is a soft magnetic material with high saturation magnetization.

The application also provides a packaging method of the magnetic component, which comprises the following steps:

fixing the chip on the upper surface of the substrate;

laying a circuit and welding spots on the circuit board;

respectively welding two ends of the circuit on the circuit board on the chip and the substrate pins through the welding spots;

a shielding member is provided to provide a magnetic shielding structure for the chip, resulting in a magnetic assembly.

Optionally, when the shielding component is a shielding frame disposed above the chip and connected to the substrate, the disposing the shielding component to provide a magnetic shielding structure for the chip includes:

connecting the shielding frame with the substrate through a magnetic shielding loop notch on the circuit board so as to form a magnetic shielding structure for the chip;

correspondingly, the wiring and welding points on the circuit board comprise:

and the circuit board is provided with the magnetic shielding loop notch penetrating through the thickness, and the circuit and the welding point are arranged on the circuit board, wherein the circuit comprises a non-direct connection circuit.

Optionally, when the substrate includes a non-magnetic shielding substrate main body and a magnetic shielding pad located on an upper surface of the non-magnetic shielding substrate main body, the fixing the chip on the upper surface of the substrate includes:

placing the magnetic shielding base plate on the upper surface of the non-magnetic shielding base plate main body;

and fixing the chip on the upper surface of the magnetic shielding base plate.

Optionally, the disposing the through-thickness magnetic shield circuit notch on the circuit board includes:

and the notch of the magnetic shielding loop penetrating through the thickness is arranged on the flexible circuit film.

Optionally, before the shielding frame is connected to the substrate through the magnetic shielding loop notch on the circuit board, the method further includes:

manufacturing a positioning mark on the substrate;

correspondingly, the connecting the shielding frame with the substrate through the magnetic shielding loop notch on the circuit board comprises:

aligning the shielding frame with the substrate by means of the positioning mark, and connecting the shielding frame with the substrate through a magnetic shielding loop notch on the circuit board.

The magnetic assembly comprises a substrate, substrate pins, a chip, a circuit board and a shielding component, wherein the chip is positioned on the upper surface of the substrate; the circuit board is provided with lines and welding spots positioned at two ends of the lines, the chip is connected with the substrate pins through the welding spots and the lines, and the shielding component provides a magnetic shielding structure for the chip.

Therefore, the magnetic assembly comprises the substrate, the substrate pins, the chip, the circuit board and the shielding component, wherein the chip is positioned on the upper surface of the substrate, the chip and the substrate pins are connected with a circuit through welding spots, namely the chip and the substrate pins are connected through the circuit board; in addition, the shielding component can be attached to the circuit board, and the reliability of subsequent plastic packaging can be ensured.

In addition, the application also provides a packaging method of the magnetic component with the advantages.

Drawings

For a clearer explanation of the embodiments or technical solutions of the prior art of the present application, the drawings needed for the description of the embodiments or prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic diagram of a prior art magnetic assembly after magnetic shielding;

FIG. 2 is a schematic top view of a conventional gold wire connecting a chip and a substrate lead;

fig. 3 is a schematic cross-sectional view of a magnetic assembly according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of another magnetic assembly provided in an embodiment of the present application;

fig. 5 is a schematic structural diagram of a substrate according to an embodiment of the present disclosure;

fig. 6 is a schematic view of a shielding frame according to an embodiment of the present application;

FIG. 7 is a schematic top view of a substrate and substrate leads according to the present application;

fig. 8 is a top view of a circuit board according to an embodiment of the present disclosure;

FIG. 9 is another schematic top view of the substrate and substrate leads of the present application;

FIG. 10 is a top view of another circuit board provided in an embodiment of the present application;

FIG. 11 is a flowchart of a method for packaging a magnetic assembly according to an embodiment of the present disclosure;

fig. 12 is a flowchart of another method for packaging a magnetic device according to an embodiment of the present disclosure.

Detailed Description

In order that those skilled in the art will better understand the disclosure, the following detailed description will be given with reference to the accompanying drawings. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

As described in the background art, a chip in a conventional magnetic assembly is connected with a substrate pin through a gold wire, and the gold wire is in contact with a magnetic shielding layer to cause a short circuit of the chip because the magnetic shielding layer is conductive, so that a sufficient distance needs to be ensured between the magnetic shielding layer and the substrate, and the height of the magnetic assembly is large; due to the structural design of the gold wire and the magnetic shielding layer, the plastic packaging material is not fully filled during plastic packaging, so that the reliability of the magnetic assembly is reduced; in order to avoid short circuit, the gold wire between the chip and the pin greatly limits the design of the side wall shielding structure of the magnetic component.

In view of the above, the present application provides a magnetic assembly, please refer to fig. 3, fig. 3 is a schematic cross-sectional view of the magnetic assembly according to an embodiment of the present application, which includes a substrate 1, substrate pins 3, a chip 2 located on an upper surface of the substrate 1, a circuit board 8, and a shielding member; the circuit board 8 is distributed with circuits and welding spots 9 positioned at two ends of the circuits, the chip 2 is connected with the substrate pins 3 through the welding spots 9 and the circuits, and the shielding component 7 provides a magnetic shielding structure for the chip 2.

The shielding member 7 is not particularly limited in the present application as the case may be. For example, when it is necessary to shield a magnetic field in a direction parallel to and perpendicular to the chip 2, the shielding member 7 is a shielding frame disposed above the chip 2 and connected to the substrate 1; wherein the line comprises a non-direct line; the circuit board 8 is provided with a magnetic shielding loop notch penetrating through the thickness, and the side wall of the shielding frame is connected with the substrate 1 through the magnetic shielding loop notch so as to form the magnetic shielding structure for the chip 2. The shielding member 7 is a shielding frame in fig. 3. The reason for the non-direct connection of the lines is that the magnetic shielding loop notch needs to be arranged on the circuit board 8, and the lines need to avoid the magnetic shielding loop notch; meanwhile, the width of the side wall of the shielding frame 7 can be increased due to the arrangement of the non-direct connection line, the difference between the width of the side wall and the width of the shielding frame 7 is reduced, and the shielding efficiency is improved. The purpose of the magnetic shielding circuit notches is to connect the shielding frame 7 with the base plate 1, forming a magnetic shielding structure for the chip 2. The shield frame 7 cannot make contact with the substrate leads 3 to avoid causing a short circuit. As can be seen from fig. 2, the gold wire 6 (shown in the dashed line frame) between the chip 2 and the pin in the conventional magnetic component greatly restricts the design of the sidewall shielding structure of the magnetic component, and the circuit board 8 is provided with the magnetic shielding loop notch 13, the circuit on the circuit board 8 is designable, so that short circuit can be effectively avoided, the reliability of the magnetic component is improved, and the circuit includes a non-direct connection circuit, so that the sidewall width of the shielding frame 7 can be increased, the difference between the sidewall width and the width of the shielding frame 7 is reduced, and the shielding efficiency is improved.

When a magnetic field parallel to the chip 2 is required to be shielded, the shielding parts are two shielding layers arranged on two sides of the chip 2, one shielding layer is located above the chip 2 for a certain distance, and the other shielding layer is located below the substrate 1, as shown in fig. 4.

The chip 2 is fixedly connected to the upper surface of the substrate 1, the circuit board 8 can be provided with circuits as required, two ends of each circuit are respectively provided with a welding spot 9, and the welding spots 9 connect the chip 2 and the substrate pins 3 after being welded with the chip 2 and the substrate pins 3, namely the chip 2 and the substrate pins 3 are connected by the circuit board 8 in the embodiment.

The shielding component is used for providing a magnetic shielding structure for the chip, so that the magnetic assembly can generate a shielding effect on an external magnetic field.

The magnetic component further includes a package body 4, the package body 4 is made of resin materials, the commonly used package material is generally epoxy resin, and the package body is low in price, good in heat resistance and high in mechanical strength.

The type of the circuit board 8 is not particularly limited in this application, and can be set by itself. The circuit board 8 is, for example, a flexible circuit film or a printed circuit board. The Printed Circuit Board is a PCB (Printed Circuit Board). The flexible circuit film, namely the flexible circuit board, is thinner than the printed circuit board, and the magnetic component adopting the flexible circuit film is thinner. The thickness of the circuit board is preferably 100um or less.

It should be noted that the kind of the chip 2 is not particularly limited in the present application, as the case may be. For example, the chip 2 may be a memory chip or a sensor chip.

The substrate 1 is not particularly limited in this application, and may be provided by itself. For example, the substrate 1 is an integrated magnetic shielding substrate, that is, the entire material of the substrate 1 is a magnetic shielding material, wherein the material of the substrate includes, but is not limited to, any one of silicon steel, pure iron, iron-nickel alloy, and permalloy. Alternatively, the base plate 1 includes a non-magnetic shield base plate main body 11 and a magnetic shield backing plate 12 on an upper surface of the non-magnetic shield base plate main body 11, as shown in fig. 5. The non-magnetic shielding substrate body 11 is made of a material without a magnetic shielding function, the non-magnetic shielding substrate body is made of copper, aluminum or the like, the magnetic shielding backing plate 12 is made of a material with a magnetic shielding function, and the material of the magnetic shielding backing plate includes, but is not limited to, any one of silicon steel, pure iron, iron-nickel alloy and permalloy.

The magnetic component comprises a substrate 1, substrate pins 3, a chip 2, a circuit board 8 and a shielding part 7, wherein the chip 2 is positioned on the upper surface of the substrate 1, the chip 2 is connected with the substrate pins 3 through welding spots 9 and circuits, namely the chip 2 is connected with the substrate pins 3 through the circuit board 8, the thickness of the circuit board 8 is small, the packaging height of the magnetic component can be reduced, and the gold wires are replaced by the circuit board 8, so that the gold wires are effectively prevented from contacting with the shielding part to generate short circuit, and the reliability of the magnetic component is improved; in addition, the shielding component can be attached to the circuit board, and the reliability of subsequent plastic packaging can be ensured.

On the basis of the above embodiment, when the shielding member is a shielding frame, in order to simplify the manufacturing process of the shielding member, preferably, the shielding frame is shaped as an inverted U, the side wall of the inverted U-shaped shielding frame is connected to the substrate, and the shielding frame is schematically illustrated in fig. 6 and includes a cover plate and side walls extending downward from the side of the cover plate. In other embodiments, the shielding frame may also be a rectangular parallelepiped with an opening, and the circuit board is provided with magnetic shielding loop notches around the circuit board.

Further, in order to facilitate the connection between the shield frame and the substrate, the substrate is provided with a positioning mark for aligning the shield frame. The positioning mark may be a groove, a small protrusion, or the like, and is not particularly limited in this application.

On the basis of the above embodiments, in an embodiment of the present application, when the shielding component is a shielding frame, in order to improve flexibility of packaging between the shielding component and the substrate, an SOP (Small Out-Line Package) packaging form is adopted between the shielding frame and the substrate.

When the SOP package is adopted, the substrate pins 3 are distributed on both sides of the substrate 1, as shown in fig. 7, the number of the substrate pins 3 is set as required, and the present application is not limited. At this time, a schematic diagram of the circuit board 8 is shown in fig. 8, non-direct-connected lines 10 are distributed on the circuit board 8, and the non-direct-connected lines 10 extend in a direction where the substrate pins are located. The position of the magnetic shield circuit notch 13 is determined according to the shape of the shield frame, and fig. 8 is a schematic view when the shape of the shield frame is an inverted U shape, and the side wall of the shield frame is connected to the substrate through the magnetic shield circuit notch.

On the basis of the above embodiments, in another embodiment of the present application, when the shielding member is a shielding frame, a QFP (Quad Flat Package) Package may be further adopted between the shielding frame and the substrate.

When the QFP package is adopted, the substrate pins 3 are distributed around the substrate 1, as shown in fig. 9, the number of the substrate pins 3 is set as required, and the present application is not limited. At this time, a schematic diagram of the circuit board 8 is shown in fig. 10, non-direct-connected lines 10 are distributed on the circuit board 8, and the non-direct-connected lines 10 extend in four directions where the substrate pins are located. The position of the magnetic shield circuit notch 13 is determined according to the shape of the shield frame, and fig. 10 is a schematic view when the shape of the shield frame is an inverted U shape, and the side wall of the shield frame is connected to the substrate through the magnetic shield circuit notch.

When the external magnetic field is large (the magnetic induction intensity is more than 1000 gauss), in order to improve the shielding efficiency of the magnetic assembly, the material of the shielding component is a soft magnetic material with high saturation magnetization.

The soft magnetic material with high saturation magnetization can be silicon steel, pure iron, iron-nickel alloy, permalloy and the like, and the shielding efficiency of the magnetic component can be improved by more than 70%. Wherein, high saturation magnetization refers to saturation magnetization >1.6T.

When the magnetic assembly shields a small external magnetic field or a magnetic field generated by electromagnetic waves, the shielding frame 77 may be made of other soft magnetic materials with a saturation magnetization of not more than 1.6T, such as low carbon steel, iron-aluminum alloy, etc., to achieve the shielding effect.

Referring to fig. 11, the present application further provides a method for packaging a magnetic device, including:

step S101: the chip is fixed on the upper surface of the substrate.

As an implementable mode, when the substrate includes a non-magnetic shield substrate main body and a magnetic shield backing plate located on an upper surface of the non-magnetic shield substrate main body, the fixing the chip on the upper surface of the substrate includes:

and fixing the chip on the upper surface of the magnetic shielding base plate.

It is understood that, when the substrate is an integrated magnetic shield substrate, when the chip is connected to the substrate, the chip may be directly fixed to the upper surface of the substrate.

Step S102: and laying lines and welding points on the circuit board.

Step S103: and respectively welding the two ends of the circuit on the circuit board on the chip and the substrate pins through the welding spots.

One end of each line is connected with the chip through a welding point, and the other end of each line is connected with the pins of the substrate through the welding point.

Step S104: a shielding member is provided to provide a magnetic shielding structure for the chip, resulting in a magnetic assembly.

It should be noted that after the shielding component is disposed, plastic packaging and rib cutting molding are further performed to obtain the magnetic assembly. The specific plastic packaging and the rib cutting process are well known to those skilled in the art, and detailed description thereof is omitted.

In order to improve the packaging efficiency of the magnetic components, batch packaging of a plurality of magnetic components can be carried out simultaneously.

The magnetic component obtained by the packaging method of the magnetic component comprises a substrate and substrate pins, wherein the substrate pins are positioned on a chip on the upper surface of the substrate, a circuit board and a shielding component, the chip and the substrate pins are connected through welding spots and lines, namely the chip and the substrate pins are connected through the circuit board, the thickness of the circuit board is small, the packaging height of the magnetic component can be reduced, the circuit board is used for replacing gold threads, the influence of the gold threads on plastic packaging materials is eliminated, and the reliability of the magnetic component is improved.

When the shielding member is a shielding frame disposed above the chip and connected to the substrate, referring to fig. 12, the method for packaging a magnetic device includes:

step S201: the chip is fixed on the upper surface of the substrate.

Step S202: and the circuit board is provided with the magnetic shielding loop notch penetrating through the thickness, and the circuit and the welding point are arranged on the circuit board, wherein the circuit comprises a non-direct connection circuit.

It should be noted that, in the present application, the position of the notch of the magnetic shielding loop is not particularly limited as long as it is ensured that the circuit and the solder joint connected with the chip are not affected.

Wherein, when the circuit board is flexible circuit film, set up on the circuit board and run through thickness the magnetism shielding return circuit notch includes: and the notch of the magnetic shielding loop penetrating through the thickness is arranged on the flexible circuit film. When the circuit board is a printed circuit board, said providing said magnetic shield circuit notch through the thickness on said circuit board comprises: the magnetic shielding loop notch penetrating through the thickness is arranged on the printed circuit board.

Step S203: and respectively welding the two ends of the circuit on the circuit board on the chip and the substrate pins through the welding spots.

Step S204: and connecting the shielding frame with the substrate through a magnetic shielding loop notch on the circuit board so as to form a magnetic shielding structure for the chip and obtain the magnetic assembly.

Wherein, the shielding frame is fixed on the substrate, and the shielding frame and the substrate can be connected by gluing or other means.

The packaging form of the magnetic component is not particularly limited in this application, as the case may be. For example, an SOP package, or a QFP package may be employed.

In order to facilitate the connection between the shielding frame and the substrate, on the basis of the above embodiments, in an embodiment of the present application, before the connecting the shielding frame with the substrate through the magnetic shielding loop notch located on the circuit board, the method further includes:

manufacturing a positioning mark on the substrate;

In the present specification, the embodiments are described in a progressive manner, and each embodiment focuses on differences from other embodiments, and the same or similar parts between the embodiments are referred to each other. The device disclosed in the embodiment corresponds to the method disclosed in the embodiment, so that the description is simple, and the relevant points can be referred to the description of the method part.

The magnetic assembly and the packaging method thereof provided by the present application are described in detail above. The principles and embodiments of the present application are described herein using specific examples, which are only used to help understand the method and its core idea of the present application. It should be noted that, for those skilled in the art, without departing from the principle of the present application, the present application can also make several improvements and modifications, and those improvements and modifications also fall into the protection scope of the claims of the present application.

Claims

1. A magnetic assembly is characterized by comprising a substrate, substrate pins, a chip positioned on the upper surface of the substrate, a circuit board and a shielding component;

2. The magnetic component of claim 1, wherein the shielding member is a shielding frame disposed over the chip and coupled to the substrate;

3. The magnetic component of claim 2, wherein the shield frame and the substrate are encapsulated in an SOP package.

4. The magnetic component of claim 2, wherein the shielding frame is shaped as an inverted U, and wherein sidewalls of the inverted U-shaped shielding frame are connected to the substrate.

5. The magnetic assembly of claim 2, wherein the substrate is provided with positioning marks for aligning the shadow frame.

6. The magnetic component of claim 1, wherein the circuit board is a flexible circuit film.

7. The magnetic component of claim 1, wherein the substrate includes a non-magnetic shielding substrate body and a magnetic shielding shim plate on an upper surface of the non-magnetic shielding substrate body.

8. A magnetic assembly according to any of claims 1 to 7, wherein the material of the shield member is a soft magnetic material having a high saturation magnetization.

9. A method of packaging a magnetic assembly, comprising:

fixing the chip on the upper surface of the substrate;

laying a circuit and welding spots on a circuit board;

10. The magnetic component packaging method of claim 9, wherein when the shielding member is a shielding frame disposed over the chip and connected to the substrate, the disposing a shielding member to provide a magnetic shielding structure for the chip comprises:

connecting the shielding frame with the substrate through a magnetic shielding loop notch on the circuit board to form a magnetic shielding structure for the chip;

correspondingly, the wiring and the welding spots on the circuit board comprise:

and arranging the magnetic shielding loop notch penetrating through the thickness on the circuit board, and arranging the line and the welding point on the circuit board, wherein the line comprises a non-direct connection line.

11. The magnetic device packaging method of claim 9, wherein when the substrate includes a non-magnetic shielding substrate body and a magnetic shielding gasket located on an upper surface of the non-magnetic shielding substrate body, the securing the chip on the upper surface of the substrate includes:

and fixing the chip on the upper surface of the magnetic shielding base plate.

12. The magnetic component packaging method of claim 10, wherein the providing the through-thickness magnetic shield circuit slot on the circuit board comprises:

13. The magnetic component packaging method of claim 10, wherein prior to connecting the shield frame to the substrate through the magnetic shield circuit notch located on the circuit board, further comprising:

manufacturing a positioning mark on the substrate;