Packaging method and corresponding packaging structure

Abstract

The invention relates to the technical field of semiconductor packaging, and provides a packaging method, which comprises the following steps that: a lead frame is provided, the lead frame comprises a base island, the surface of the base island is provided with a specified area for mounting a chip, and the outer side of the specified area is provided with a routing area; applying a first magnetic field to a designated area on the surface of the base island; providing glue, and enabling the glue to flow to a designated area on the surface of the base island to form a glue point; wherein the glue is provided with magnetic powder; the magnetic control glue points form a glue layer with a regular shape in the designated area under the action of the first magnetic field; and mounting a chip on the surface of the glue layer in the process of the first magnetic field. The three-dimensional shape of the glue is controllable through the magnetic control glue, the surface tension of the glue is enough to pull the chip, and the risk of suck-back of the chip is greatly reduced; and the adhesive force of the chip does not need to be increased by pressing the glue downwards, so that the upturning risk of the chip and the overflow contamination risk of the glue are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor packaging, and discloses a packaging method and a corresponding packaging structure. Background Art

[0002] Using glue to dispense onto leadframes is a common method for semiconductor packaging. However, when the chip is placed onto the glue surface, the nozzle's negative pressure is not released quickly enough, resulting in a small contact area between the glue and the chip. The glue's surface tension is insufficient to hold the chip in place, creating a risk of the chip being sucked back. In this situation, increasing the downward pressure on the soldering head prevents the chip from being sucked back, but can lead to excessive glue overflow, contaminating the bonding area of ​​the base island. Furthermore, excessive downward pressure can lead to excessive glue creep, contaminating the chip's bond pad, and compromising wire bonding and package reliability. Summary of the Invention

[0003] The purpose of the present invention is to solve the problem that the common way of semiconductor packaging is to use glue to dispense chips on the lead frame, which may cause the chip to be sucked back or contaminate the ground area of ​​the lead frame. A packaging method and a corresponding packaging structure are provided. In order to achieve the above object, the present invention provides a packaging method, comprising: Providing a lead frame, the lead frame comprising a base island, the base island surface having a designated area for mounting a chip, and the outer side of the designated area on the base island surface having a bonding area; applying a first magnetic field to a designated area on the surface of the base island; Providing glue and allowing the glue to flow to a designated area on the surface of the base island to form glue spots; wherein the glue contains magnetic powder; Under the action of the first magnetic field, the magnetically controlled glue dots form a glue layer with a regular shape in the designated area; The chip is mounted on the surface of the glue layer during the process of applying the first magnetic field.

[0004] As an implementation method, the step of forming a glue layer having a regular shape in the designated area by the magnetically controlled glue dots under the action of the first magnetic field includes: Under the action of the first magnetic field, the magnetic powder in the glue dot is caused to be oriented along the direction of the magnetic field to form a magnetic response channel, thereby driving the glue dot to form a glue layer with a regular shape and a flat upper surface.

[0005] As an implementable embodiment, the magnetic powder is evenly distributed in the glue.

[0006] As an implementation method, the magnetic powder is a conductive material or an insulating material.

[0007] As an implementation method, when the magnetic powder is a conductive material, the magnetic powder is ferromagnetic metal powder or ferrite magnetic powder, and the ferromagnetic metal powder is one of iron powder, cobalt powder and nickel powder; the ferrite magnetic powder is manganese zinc ferrite magnetic powder or nickel zinc ferrite magnetic powder; when the magnetic powder is an insulating material, the magnetic powder is one of graphite powder, silica powder and alumina powder.

[0008] As an implementation method, the proportion of the magnetic powder in the total filler in the glue is in the range of 20% to 30%. As an implementation method, the diameter of the magnetic powder ranges from 5 μm to 10 μm.

[0009] As an implementation method, the first magnetic field is a vertical magnetic field, and the first magnetic field is located above a designated area on the surface of the base island.

[0010] As an implementation method, there is at least one first magnetic field, the number of the first magnetic fields corresponds to the number of the glue layers, and the surface of each glue layer is used for mounting a corresponding chip.

[0011] As an implementation method, the area of ​​each glue layer is greater than or equal to the area of ​​the corresponding chip.

[0012] As an implementable embodiment, there is at least one glue dot and at least one glue layer, and the number of the glue dots and the number of the glue layers are the same or different.

[0013] As an implementation method, when there are at least two glue layers, the shapes and surface areas of the at least two glue layers are the same or different.

[0014] As an implementable embodiment, the regular shape is one or more of a triangle, a square, a rectangle, a hexagon, an octagon and a circle.

[0015] As an implementable embodiment, the glue is conductive glue or insulating glue.

[0016] As an implementable embodiment, when the glue is conductive glue, the glue also contains conductive powder.

[0017] As an implementable embodiment, the conductive powder is evenly distributed in the glue.

[0018] As an implementation method, the proportion of the conductive powder in the total filler in the glue is greater than or equal to 60%.

[0019] As an implementable embodiment, the glue further includes a toughening agent, and the toughening agent is used to improve the flexibility of the glue.

[0020] As an implementation method, the glue further includes a curing agent, and the curing agent is used to shorten the curing time of the glue during the process of baking the glue after chip mounting.

[0021] As an implementation method, the glue further includes a dispersant, and the dispersant is used to improve the dispersion uniformity of the magnetic powder in the glue.

[0022] As an implementation method, the glue further includes a diluent, and the diluent is used to increase the viscosity of the glue to improve the flow control capability of the magnetic field.

[0023] As an implementation method, the viscosity of the glue is in the range of 500 mPa·s to 1000 mPa·s. As an implementable embodiment, it also includes: Applying a second magnetic field to the bonding area that repels the glue; The chip is mounted on the surface of the glue layer during the application of the second magnetic field.

[0024] As an implementable embodiment, it also includes: During the application of the second magnetic field, the glue is allowed to flow to a designated area on the surface of the base island to form glue spots and a glue layer.

[0025] As an implementation method, the second magnetic field is a vertical magnetic field, and the second magnetic field is located above the bonding area.

[0026] As an implementation method, the number of the second magnetic fields is the same as the number of the bonding areas.

[0027] As an implementation method, there are two bonding areas, which are respectively located at edge portions on two opposite sides of the base island surface.

[0028] As an implementation method, the step of applying a second magnetic field to a designated area on the surface of the base island includes: The base island surface is positioned according to the bonding area on the base island surface, and a second magnetic field is applied to the bonding area on the base island surface according to the positioning.

[0029] As an implementation method, the step of applying a first magnetic field to a designated area on the surface of the base island includes: The base island surface is positioned according to the pre-mounting position of the chip in the designated area of ​​the base island surface, and a first magnetic field is applied to the designated area of ​​the base island surface according to the positioning.

[0030] As an implementation method, the step of allowing the glue to flow to a designated area on the surface of the base island to form a glue point includes: During the application of the first magnetic field, the glue flows to the designated area on the surface of the base island through the glue tube under the action of the magnetic field and the glue dispensing air pressure to form glue spots, and the glue spots are inclined structures that are narrow at the top and wide at the bottom.

[0031] As an implementation method, after the step of mounting the chip on the surface of the glue layer under the action of the first magnetic field, the method further includes: The chip surface and the bonding area on the island surface are connected by wires.

[0032] Accordingly, the present invention further provides a packaging structure prepared by the above packaging method, comprising: A base island, wherein a surface of the base island has a designated area for mounting a chip; a glue layer, located on a designated area on the surface of the base island, the glue layer having magnetic powder; A chip is located on the surface of the glue layer; A lead connects the bonding area and the chip surface.

[0033] The present invention proposes a packaging method and a corresponding packaging structure, in which a regular shape is formed by magnetically controlling the glue through a first magnetic field, so that the three-dimensional shape of the glue is controllable, and the surface tension of the glue is sufficient to hold the chip, greatly reducing the risk of chip suction; there is no need to press down the glue to increase the chip adhesion, reducing the risk of the chip turning over and the risk of glue overflow and contamination; the glue shape can be flexibly arranged into various complex shapes according to a preset pattern, facilitating the packaging application of multi-chip modules and special-shaped chips; it no longer relies on the downward pressure of the welding head to meet the glue coverage rate, the glue coverage area can be greater than or equal to the chip area, and the coverage rate is controllable; and, since the magnetic control dispensing output and the dispensing shape XYZ are both controllable, the dispensing head does not need to be too small, avoiding the clogging of the dispensing head by partial glue deposition.

[0034] The present invention prevents the glue from overflowing into the bonding area through the repulsive effect between the second magnetic field and the glue, thereby avoiding affecting the bonding wires and improving the packaging reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of a packaging process provided for explaining technical problems in some embodiments of the present invention; Figure 2 A flowchart of the packaging method steps provided for some embodiments of the present invention; Figure 3-5 A schematic diagram of a packaging process for applying a first magnetic field to a designated area according to some embodiments of the present invention; Figure 6 A schematic diagram of applying a first magnetic field to a designated area according to some embodiments of the present invention; Figure 7A schematic diagram of applying a second magnetic field to a bonding area according to some embodiments of the present invention. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] It should be understood that as used herein, terms such as "first" and "second" describe various elements, components, regions, layers and / or sections, and these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer or section from another element, component, region, layer or section. For example, terms such as "first" and "second" do not imply a sequence or order when used herein unless the context clearly indicates. For ease of description, spatially relative terms such as "upper" and "lower" may be used herein to describe the relationship of one element or feature to other elements or features as shown in the accompanying drawings. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientations shown in the accompanying drawings.

[0038] In this application, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two elements, or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0039] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory. It should be noted that the terms "including" and "having" and their variations involved in this application are intended to cover non-exclusive inclusions.

[0040] In the existing film mounting process, see Figure 1 The surface of the lead frame's base island 10 has a designated area for chip mounting, and the outer side of the designated area has a bonding area 20. Glue 31 is applied to the designated area, and then the chip 40 is mounted on the surface of the glue 31. Since the surface area of ​​contact between the glue 31 and the chip 40 is small, when the chip 40 sucked by the nozzle is mounted on the surface of the glue 31, the negative pressure of the nozzle is not released in time, and the surface tension of the glue 31 is insufficient to hold the chip, there is a risk of the chip being sucked back. In the above situation, if the downward pressure parameter of the chip mounting welding head is increased, the chip 40 will not be sucked back, but the glue 31 may overflow to the surrounding area and contaminate the bonding area 20, thereby affecting the bonding wire and packaging reliability.

[0041] Some embodiments of the present invention provide a packaging method, see Figure 2 ,include: Step S100: providing a lead frame, wherein the lead frame comprises a base island, a surface of the base island has a designated area for mounting a chip, and an outer side of the designated area has a bonding area.

[0042] In some embodiments, the material of the lead frame is metal, and the metal may be one or more of aluminum, tin, tungsten, platinum, copper, titanium, chromium, tantalum, gold, and silver.

[0043] In some embodiments, the lead frame includes a base island and pins located outside the base island. Figure 3The surface of the base island 100 has a designated area for chip mounting, and a bonding area 200 is provided outside the designated area on the surface of the base island 100. In some embodiments, the designated area is located in the middle portion of the surface of the base island 100, and the bonding area 200 is located at the edge of the surface of the base island 100; in some embodiments, the designated area is located on one side of the base island, and the bonding area is located on the other side of the base island; in some embodiments, there are multiple designated areas, the bonding area is located in the middle portion of the surface of the base island 100, and multiple designated areas are arranged around the bonding area.

[0044] In step S200 , a first magnetic field is applied to a designated area on the surface of the base island 100 .

[0045] In some embodiments, see, for example, Figure 6 A first magnetic field can be applied above the designated area. In some embodiments, the first magnetic field can be a perpendicular magnetic field, which can magnetically control the magnetic powder, constraining and guiding its movement. However, in other embodiments, other types of magnetic fields that can magnetically control the magnetic powder and achieve corresponding functions can be selected, such as oblique magnetic fields, which can also constrain and guide the particles.

[0046] In some embodiments, the step of applying a first magnetic field to a designated area on the surface of the base island 100 includes: The surface of the base island 100 is positioned according to the pre-mounting position of the chip in a designated area on the surface of the base island 100, and a first magnetic field is applied to the designated area on the surface of the base island 100 based on the positioning. Specifically, the applied magnetic field can be interconnected with the PR serial port of the chip loading equipment for positioning, thereby locating the position of the first magnetic field based on the chip loading position.

[0047] In some embodiments, see Figure 7 , a second magnetic field that repels the glue can also be applied to the bonding area 200, specifically a second magnetic field that repels the magnetic powder in the glue; by controlling the magnetic field power, the repulsive magnetic fields are kept at a reasonable distance to avoid deviation in the glue dispensing position, and further prevent the glue layer 302 from overflowing into the bonding area 200. In some embodiments, the second magnetic field can be a vertical magnetic field or an oblique magnetic field, etc. When the second magnetic field is a vertical magnetic field, the second magnetic field can be located above the bonding area 200. In some embodiments, the principle of repulsion between the magnetic field and magnetic powder involves the influence of the magnetic field on the magnetic powder. When the magnetic field is close to the magnetic powder, the magnetic powder will be magnetized to form small magnets and arranged along the direction of the magnetic field. According to the principle that like poles repel and unlike poles attract, if these small magnets have the same polarity as the magnetic field direction, they will be repelled.

[0048] In some embodiments, the number of the second magnetic fields is the same as the number of the bonding areas. Figure 7 When the bonding area 200 is located at the edge of the surface of the base island 100, there are two bonding areas 200, one located at the edge of the surface of the base island 100 on opposite sides. The second magnetic field is also two corresponding ones, so that the first magnetic field guides the magnetic powder to form a regular shape along the direction of the magnetic field indicated by the solid arrow in the figure, while the second magnetic field applies a magnetic field to the bonding area along the dotted line in the figure. Based on the principle that like poles repel, the magnetic field polarity is controlled to repel the magnetic powder in the glue. In some embodiments, the repulsive magnetic fields can be kept at a reasonable distance by controlling the power of the second magnetic field to avoid deviation in the dispensing position.

[0049] In some embodiments, the step of applying a second magnetic field to the bonding area 200 on the surface of the base island 100 includes: positioning the base island surface according to the bonding area on the base island surface, and applying a second magnetic field to the bonding area on the base island surface according to the positioning.

[0050] Step S300 , providing glue and allowing the glue to flow to a designated area on the surface of the base island to form glue dots 301 ; wherein the glue contains magnetic powder.

[0051] In some embodiments, the glue is a conductive glue or an insulating glue. In some embodiments, when the glue is a conductive glue, the glue further contains a conductive powder. The conductive powder is a metal, and the metal is one or more of aluminum, nickel, tin, tungsten, platinum, copper, titanium, chromium, tantalum, gold, silver, etc.

[0052] In some embodiments, when the glue is an insulating glue, the glue layer can be controlled to form a regular shape, thereby controlling the thickness and area of ​​the glue layer to prevent leakage. In some embodiments, the conductive powder accounts for greater than or equal to 60% of the total filler in the glue to ensure the continuity of the conductive network. In some embodiments, the conductive powder is evenly distributed in the glue.

[0053] In some embodiments, the magnetic powder is a conductive material or an insulating material. In some embodiments, when the magnetic powder is a conductive material, the magnetic powder is ferromagnetic metal powder or ferrite powder, and the ferromagnetic metal powder is one of iron powder, cobalt powder, and nickel powder; the ferrite powder is manganese-zinc ferrite powder or nickel-zinc ferrite powder; when the magnetic powder is an insulating material, the magnetic powder is one of graphite powder, silica powder, and alumina powder.

[0054] In some embodiments, the magnetic powder is evenly distributed in the glue. In some embodiments, the magnetic powder accounts for 20% to 30% of the total filler in the glue to avoid excessive amounts that could block the conductive path. In some embodiments, the magnetic powder has a diameter ranging from 5 μm to 10 μm. Avoid small diameters that cause agglomeration and large diameters that reduce magnetic field sensitivity.

[0055] In certain embodiments, the glue further comprises a toughening agent, which is used to improve the flexibility of the glue. The main purpose of improving the flexibility of the glue is to enhance its durability and reliability in practical applications. Specifically, the glue with good flexibility can still maintain its bonding performance when facing physical stress, vibration or temperature changes, thereby avoiding the bonding failure caused by glue embrittlement. In certain embodiments, the toughening agent can be polysulfide rubber (JLY-121).

[0056] In some embodiments, the glue further includes a curing agent, which is used to shorten the curing time of the glue during the baking process after chip mounting. In some embodiments, the curing agent can be T31 curing agent.

[0057] In some embodiments, the glue further includes a dispersant, which is used to improve the uniformity of the dispersion of the magnetic powder in the glue. In some embodiments, the dispersant may be BYK-111 dispersant.

[0058] In some embodiments, the glue further includes a diluent to increase the glue's viscosity, thereby enhancing the magnetic field's flow control capabilities. In some embodiments, the diluent can be acetone. In some embodiments, the glue's viscosity ranges from 500 mPa·s to 1000 mPa·s, balancing the requirements of magnetic field traction and the glue dispensing process.

[0059] As a specific embodiment, the steps of forming glue are as follows: Step 1: Mix epoxy resin and acetone and stir until completely dissolved; Step 2: Add polysulfide rubber and BYK-111 dispersant in sequence and stir at low speed for 5 minutes; Step 3: Add silver powder and nickel powder in batches and disperse at high speed for 30 minutes to avoid introducing bubbles; Step 4: Finally, add T31 curing agent, stir evenly and then vacuum degas for 10 minutes; Step 5: After applying the glue, apply a vertical magnetic field (0.1-0.5T) before curing to encourage the nickel powder to align along the direction of the magnetic field to form a magnetic response channel; Step 6: Curing conditions after mounting: pre-curing at 80°C for 1 hour (initial shaping) and post-curing at 120°C for 2 hours (complete cross-linking).

[0060] In some embodiments, the step of allowing the glue to flow to a designated area on the surface of the base island to form glue spots includes: in the process of applying a first magnetic field, allowing the glue to flow to a designated area on the surface of the base island under the action of the magnetic field and the glue dot pressure through a glue tube to form glue spots, and the glue pad is a slope structure that is narrow at the top and wide at the bottom.

[0061] Specifically, the resistance of glue flowing from the hose to the dispensing head increases. Due to the glue viscosity and the fluid adhesion effect, residual glue accumulates and solidifies, resulting in blockage and failure of dispensing. However, some embodiments of the present invention, through the dual action of magnetic control and air pressure, facilitate the flow of glue from the hose, preventing glue sediment from clogging the dispensing head, reducing the frequency of dispensing head replacement and improving production efficiency. In addition, because the dispensing output and the X, Y, and Z shapes of the dispensing are both controllable, the dispensing head does not need to be too small, thus avoiding partial glue accumulation and clogging the dispensing head.

[0062] Step S400: Under the action of the first magnetic field, the magnetically controlled glue dots form a glue layer with a regular shape in the designated area.

[0063] Some embodiments of the present invention use magnetically controlled glue dots to make the three-dimensional shape of the glue dots controllable. The surface tension of the glue is sufficient to hold the chip, greatly reducing the risk of chip suction. The glue does not need to be pressed down to increase the adhesion of the chip, reducing the risk of the chip flipping over and the risk of glue overflow and contamination. Moreover, the shape of the glue can be flexibly arranged into various complex shapes according to preset patterns, facilitating the packaging of multi-chip modules and special-shaped chips.

[0064] In some embodiments, the step of forming a glue layer with a regular shape in the designated area by the magnetically controlled glue dots under the action of the first magnetic field includes: under the action of the first magnetic field, causing the magnetic powder in the glue dots to be oriented along the direction of the magnetic field to form a magnetic response channel, thereby driving the glue dots to form a glue layer with a regular shape and a flat upper surface.

[0065] Specifically, under the influence of an external perpendicular magnetic field, the magnetic moment of the magnetic powder particles tends to align parallel to the magnetic field. This orientation of the magnetic moment causes the magnetic powder to align in a specific manner within the field. Just as small magnetic needles align neatly in a magnetic field, numerous magnetic powder particles also align in an orderly manner according to the magnetic field, resulting in the glue dots forming a regularly shaped glue layer. In some embodiments, this regular shape can be controlled by the magnetic field to assume a specific shape.

[0066] In some embodiments, the regular shape is one or more of a triangle, a square, a rectangle, a hexagon, an octagon, and a circle. Figure 3 In (b), the glue layer 302 is an L-shaped hexagon; see Figure 4 In (b), the glue layer 302 is rectangular; see Figure 5In (b), the glue layer 302 is square. In some embodiments, the upper surface of the regular shape is flat, so as to further increase the instantaneous contact area with the chip and further prevent the chip from being sucked back.

[0067] In some embodiments, there is at least one first magnetic field, and the number of the first magnetic fields corresponds to the number of the glue layers, and the surface of each glue layer is used to mount a corresponding chip. That is, when two chips are to be mounted in a designated area, two magnetic fields can be applied to the designated area, thereby forming two glue layers for mounting the chips. For example, see Figure 4 In (b), two first magnetic fields can be used to control the formation of two glue layers, see Figure 3 (b) and Figure 5 (b) in the figure can be controlled by a first magnetic field to form a corresponding glue layer.

[0068] In some embodiments, the area of ​​each glue layer 302 is greater than or equal to the area of ​​the corresponding chip 400 , further increasing the instantaneous contact area between the glue layer 302 and the chip 400 and reducing the risk of chip suction.

[0069] In some embodiments, there is at least one glue dot 301 and at least one glue layer 302 , and the number of the glue dot 301 and the number of the glue layer 302 can be the same or different.

[0070] In some embodiments, when the number of the glue dots 301 is different from the number of the glue layers 302, see Figure 4 , the number of the glue point 301 is one, and the number of the glue layers 302 formed is at least two. Figure 5 There are at least two glue dots 301, and one glue layer 302 is formed accordingly.

[0071] In some embodiments, when there are at least two glue layers 302, the regular shapes or surface areas of the at least two glue layers 302 are the same or different. Figure 4 In (b), the surface areas of the two glue layers 302 are different.

[0072] In some embodiments, when a second magnetic field that repels the glue is applied to the bonding area, the method further includes: allowing the glue to flow to a designated area on the surface of the base island to form glue spots and a glue layer during the application of the second magnetic field.

[0073] Step S500 : mounting the chip on the surface of the glue layer during the process of applying the first magnetic field.

[0074] In some embodiments, see Figure 3 、 Figure 4 and Figure 5 In (c), the chip 400 is mounted on the surface of the glue layer 302 during the application of the first magnetic field, so that the chip 400 is mounted while the magnetron glue layer 302 maintains a regular shape, thereby improving packaging reliability.

[0075] In some embodiments, when a second magnetic field that repels the glue is applied to the bonding area, the method further includes: mounting the chip on the surface of the glue layer during the application of the second magnetic field.

[0076] In some embodiments, the chip 400 may include a power chip, a logic chip, or a memory chip. In some embodiments, the logic chip may include a gate array, a cell substrate array, an embedded array, a structured application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a complex programmable logic device (CPLD), a central processing unit (CPU), a microprocessing unit (MPU), a microcontroller unit (MCU), a logic integrated circuit (IC), an application processor (AP), a display driver IC (DDI), a radio frequency (RF) chip, a power chip, or a complementary metal oxide semiconductor (CMOS) image sensor. In some embodiments, the memory chip may include a volatile memory chip (such as a dynamic random access memory (DRAM) or a static RAM (SRAM) or a non-volatile memory chip (such as a flash memory (Flash), a phase change RAM (PRAM), a magnetoresistive RAM (MRAM), a ferroelectric RAM (FeRAM), or a resistive RAM (ReRAM)). In a specific embodiment, the memory chip may include a high-bandwidth memory (HBM) including a DRAM chip.

[0077] In some embodiments, after the step of attaching the chip to the surface of the glue layer under the action of the first magnetic field, the method further includes: connecting the chip surface to the bonding area on the base island surface using wires. In some embodiments, the method further includes plastic encapsulation and some cutting of the lead frame.

[0078] Accordingly, see Figure 3-Figure 5 In (c), the present invention further provides a packaging structure prepared according to the above-mentioned packaging method, comprising: a base island 100, wherein the surface of the base island 100 has a designated area for chip mounting, and the outer side of the designated area has a bonding area 200; a glue layer 302 located on the surface of the base island 100; wherein the glue layer 302 contains magnetic powder; and a chip 400 located on the surface of the glue layer 302. In some embodiments, it also includes a lead, wherein the lead connects the bonding area and the chip surface. In some embodiments, it also includes a molding compound, which can be an epoxy resin, a polyimide resin, a benzocyclobutene resin, or a polybenzoxazole resin, and the molding process can be an injection molding process or a transfer molding process.

[0079] Although the present invention has been disclosed above in terms of preferred embodiments, this is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the scope of protection of the technical solutions of the present invention.

Claims

1. A packaging method, characterized in that: include: Providing a lead frame, the lead frame comprising a base island, the base island surface having a designated area for mounting a chip, and the outer side of the designated area on the base island surface having a bonding area; applying a first magnetic field to a designated area on the surface of the base island; Providing glue and allowing the glue to flow to a designated area on the surface of the base island to form glue spots; wherein the glue contains magnetic powder; Under the action of the first magnetic field, the magnetically controlled glue dots form a glue layer with a regular shape in the designated area; The chip is mounted on the surface of the glue layer during the process of applying the first magnetic field.

2. The packaging method according to claim 1, wherein: The step of forming a glue layer having a regular shape in the designated area by the magnetically controlled glue dots under the action of the first magnetic field comprises: Under the action of the first magnetic field, the magnetic powder in the glue dot is caused to be oriented along the direction of the magnetic field to form a magnetic response channel, thereby driving the glue dot to form a glue layer with a regular shape and a flat upper surface.

3. The packaging method according to claim 1, wherein: The magnetic powder is evenly distributed in the glue.

4. The packaging method according to claim 1, wherein: The magnetic powder is a conductive material or an insulating material.

5. The packaging method according to claim 4, wherein: When the magnetic powder is a conductive material, the magnetic powder is ferromagnetic metal powder or ferrite powder, and the ferromagnetic metal powder is one of iron powder, cobalt powder and nickel powder; the ferrite powder is manganese-zinc ferrite powder or nickel-zinc ferrite powder; when the magnetic powder is an insulating material, the magnetic powder is one of graphite powder, silica powder and alumina powder.

6. The packaging method according to claim 1, wherein: The proportion of the magnetic powder in the total filler in the glue is in the range of 20% to 30%.

7. The packaging method according to claim 1, wherein: The diameter of the magnetic powder ranges from 5 μm to 10 μm.

8. The packaging method according to claim 1, wherein: The viscosity of the glue ranges from 500 mPa·s to 1000 mPa·s.

9. The packaging method according to claim 1, wherein: The first magnetic field is a vertical magnetic field, and the first magnetic field is located above a designated area on the surface of the base island.

10. The packaging method according to claim 1, wherein: There is at least one first magnetic field, the number of the first magnetic fields corresponds to the number of the glue layers, and the surface of each glue layer is used for mounting a corresponding chip.

11. The packaging method according to claim 10, characterized in that: The area of ​​each glue layer is greater than or equal to the area of ​​the corresponding chip.

12. The packaging method according to claim 1, wherein: There is at least one glue dot and at least one glue layer, and the number of the glue dots and the number of the glue layers are the same or different.

13. The packaging method according to claim 12, wherein: When there are at least two glue layers, the shapes and surface areas of the at least two glue layers are the same or different.

14. The packaging method according to claim 1, wherein: The regular shape is one or more of a triangle, a square, a rectangle, a hexagon, an octagon and a circle.

15. The packaging method according to claim 1, wherein: The glue is conductive glue or insulating glue.

16. The packaging method according to claim 15, characterized in that: When the glue is conductive glue, the glue also contains conductive powder.

17. The packaging method according to claim 16, wherein: The conductive powder is evenly distributed in the glue.

18. The packaging method according to claim 16, wherein: The proportion of the conductive powder in the total filler in the glue is greater than or equal to 60%.

19. The packaging method according to claim 1, wherein: The glue also includes a toughening agent, which is used to improve the flexibility of the glue.

20. The packaging method according to claim 1, wherein: The glue also includes a curing agent, which is used to shorten the glue curing time during the glue baking process after chip mounting.

21. The packaging method according to claim 1, wherein: The glue further comprises a dispersant, and the dispersant is used to improve the dispersion uniformity of the magnetic powder in the glue.

22. The packaging method according to claim 1, wherein: The glue also includes a diluent, and the diluent is used to increase the viscosity of the glue to improve the magnetic field flow control capability.

23. The packaging method according to claim 1, wherein: Also includes: Applying a second magnetic field to the bonding area that repels the glue; The chip is mounted on the surface of the glue layer during the application of the second magnetic field.

24. The packaging method according to claim 23, wherein: Also includes: During the application of the second magnetic field, the glue is allowed to flow to a designated area on the surface of the base island to form glue spots.

25. The packaging method according to claim 23, wherein: The second magnetic field is a vertical magnetic field, and the second magnetic field is located above the bonding area.

26. The packaging method according to claim 23, characterized in that: The number of the second magnetic fields is the same as the number of the bonding areas.

27. The packaging method according to claim 1 or 26, characterized in that: There are two bonding areas, which are respectively located at edge portions on two opposite sides of the base island surface.

28. The packaging method according to claim 23, wherein: The step of applying a second magnetic field to a designated area on the surface of the base island comprises: The base island surface is positioned according to the bonding area on the base island surface, and a second magnetic field is applied to the bonding area on the base island surface according to the positioning.

29. The packaging method according to claim 1, wherein: The step of applying a first magnetic field to a designated area on the surface of the base island comprises: The base island surface is positioned according to the pre-mounting position of the chip in the designated area of ​​the base island surface, and a first magnetic field is applied to the designated area of ​​the base island surface according to the positioning.

30. The packaging method according to claim 1, wherein: The step of allowing the glue to flow to a designated area on the surface of the base island to form a glue point includes: During the application of the first magnetic field, the glue flows to the designated area on the surface of the base island through the glue tube under the action of the magnetic field and the glue dispensing air pressure to form glue spots, and the glue spots are inclined structures that are narrow at the top and wide at the bottom.

31. The packaging method according to claim 1, wherein: After the step of mounting the chip on the surface of the glue layer under the action of the first magnetic field, the method further includes: The chip surface and the bonding area on the island surface are connected by wires.

32. A packaging structure prepared by the packaging method according to any one of claims 1 to 31, characterized in that: include: A base island, wherein a surface of the base island has a designated area for mounting a chip; a glue layer, located on a designated area on the surface of the base island, the glue layer having magnetic powder; A chip is located on the surface of the glue layer; A lead connects the bonding area and the chip surface.

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