Packaging structure and method of two-phase switching converter

Abstract

The invention provides a packaging structure and method of a two-phase switching converter. The packaging structure comprises a first packaging body and an inductor assembly, wherein the inductor assembly is stacked on the top of the first packaging body. The first packaging body comprises a substrate, two wafers, a passive element and four metal columns, wherein the two wafers, the passive element and the four metal columns are installed on the substrate. Two power switch devices are arranged in each wafer, and the common end of the two switch devices serves as a switch bonding pad of the wafer. The metal columns are used for electrically connecting one ends of the two coils in the inductor assembly with the switch bonding pads of the wafer through the substrate and electrically connecting the other ends of the two coils in the inductor assembly with the output pins of the substrate. The packaging structure provided by the invention occupies a small area and a small space position of a PCB (Printed Circuit Board), has good heat dissipation performance, and is suitable for a large-current occasion in which a two-phase switching converter is applied.

Description

Technical Field

[0001] The present invention relates to the field of integrated circuit packaging, and in particular to a packaging structure and method of a dual-phase switching converter. Background Art

[0002] As electronic devices develop towards miniaturization and multifunctionality, the types and quantities of chips and passive components that need to be integrated and packaged together are also increasing, so the requirements for packaging structure and packaging process are gradually increasing. Semiconductor packaging provides support for integrated circuit chips or semiconductor wafers, provides protection from environmental influences, and can be installed on external components and interconnected with external components.

[0003] The power switch converter module includes at least an integrated chip with power switch device and controller functions, as well as passive components such as input capacitors, output capacitors and inductors. In a two-phase converter, the number of chips and passive components is doubled. The size of the area and volume must be considered when combining these components into a single package. At the same time, heat dissipation is also an important aspect that we need to consider. Summary of the invention

[0004] In view of the problems existing in the prior art, a packaging structure of a dual-phase switching converter and a preparation method thereof are provided.

[0005] The first aspect of the present invention proposes a packaging structure of a two-phase switching converter, including an inductor assembly, a substrate, and a first chip, a second chip and four metal pillars mounted on the substrate. The first chip and the second chip both have a switch pad; the first metal pillar is electrically connected to the switch pad of the first chip through the substrate; the second metal pillar is electrically connected to the output pin of the substrate; the third metal pillar is electrically connected to the switch pad of the second chip through the substrate; and the fourth metal pillar is electrically connected to the output pin of the substrate. The plastic encapsulation material wraps the first chip, the second chip and the four metal pillars, and exposes the top surfaces of the four metal pillars to the outside of the plastic encapsulation material. The inductor assembly is stacked on the top surfaces of the four metal pillars.

[0006] The second aspect of the present invention proposes a packaging method for a dual-phase switching converter. The method includes: providing a substrate; mounting a first chip and a second chip on the substrate, wherein the first chip and the second chip both have a switch pad; mounting a first metal column, a second metal column, a third metal column and a fourth metal column on the substrate through an adhesive, wherein the first metal column is electrically connected to the switch pad of the first chip through the substrate, the third metal column is electrically connected to the switch pad of the second chip through the substrate, and the second metal column and the fourth metal column are electrically connected to the output pin of the substrate; using a plastic encapsulation material to wrap the first chip, the second chip, the first metal column, the second metal column, the third metal column and the fourth metal column, and exposing the top surfaces of the first metal column, the second metal column, the third metal column and the fourth metal column to the outside of the plastic encapsulation material; mounting an inductor component on the top surfaces of the first metal column, the second metal column, the third metal column and the fourth metal column.

[0007] Compared with the prior art, the package junction prepared by the above technical solution occupies a small area and space position on the PCB, and has good heat dissipation performance, which is suitable for high current applications of dual-phase switching converters. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1A An overall diagram of a packaging structure 100 of a dual-phase switching converter is shown according to an embodiment of the present invention;

[0009] Figure 1B A cross-sectional view of a packaging structure 100 of a dual-phase switching converter is shown according to an embodiment of the present invention.

[0010] Figure 2A A perspective view of a first package body in a package structure 100 is shown according to an embodiment of the present invention;

[0011] Figure 2B According to one embodiment of the present invention, an external view of a first package body in a package structure 100 is shown;

[0012] Figure 3A -D is a process flow chart of preparing a packaging structure 100 according to an embodiment of the present invention;

[0013] Figure 4 According to another embodiment of the present invention, a cross-sectional view of a dual-phase switching converter packaging structure 200 is shown;

[0014] Figure 5 An external view of a first package body of a dual-phase switching converter package structure 200 is shown according to an embodiment of the present invention;

[0015] Figure 6 According to yet another embodiment of the present invention, a cross-sectional view of a dual-phase switching converter packaging structure 200 is shown;

[0016] Figure 7 An external view of a first package body of a dual-phase switching converter package structure 200 is shown according to an embodiment of the present invention.

[0017] Figure numerals: 11-substrate, 12-1-first chip, 12-2-second chip, 13-metal column, 13-1-first metal column, 13-2-second metal column, 13-3-third metal column, 13-4-fourth metal column, 14-plastic packaging material, 15-passive component, 15-1-input capacitor, 15-2-other passive components, 16-adhesive, 17-connecting material, 18-insulating glue, 28-conductive glue, 38-heat dissipation adhesive, 12-1-a-control stage of the first chip 12-1, 12-2-a-control stage of the second chip 12-2. DETAILED DESCRIPTION

[0018] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar modules or modules with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be construed as limitations on the present application. On the contrary, the embodiments of the present application include all changes, modifications and equivalents that fall within the spirit and connotation of the appended claims.

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. In the description of the present invention, it should be noted that if the terms "upper", "lower", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the product of the invention is usually placed when used, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. If the terms "first", "second", etc. appear, they are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0022] In addition, throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "in one embodiment," "in an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. Furthermore, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any appropriate combinations and / or subcombinations.

[0023] Figure 1A and Figure 1B According to an embodiment of the present invention, an overall view and a cross-sectional view of a packaging structure 100 of a dual-phase switching converter are shown, wherein Figure 1B for Figure 1A The cross-sectional view along the A-A' direction. Figure 1A As shown, the package structure includes a first package body and an inductor component, wherein the inductor component is vertically mounted on the first package body. Figure 1B As shown, the first package includes a substrate 11 , a first chip 12 - 1 , a second chip 12 - 2 , a metal pillar 13 , a molding compound 14 and a passive component 15 .

[0024] The substrate 11 may be a molded component including a dielectric and a patterned printed metal trace, and the dielectric may be formed of a non-conductive plastic or resin material. The substrate 11 has chip pins at the bottom, and the chip pins may be mounted on an external component (e.g., a printed circuit board PCB) and interconnected with the external component. The first wafer and the second wafer are attached to the substrate and electrically connected to the chip pins at the bottom of the substrate through the metal traces of the substrate.

[0025] The first chip 12-1 and the second chip 12-2 are mounted on the substrate. The top surfaces of the first chip 12-1 and the second chip 12-2 both have chip pads, and the internal components of the first chip 12-1 and the second chip 12-2 are connected to the substrate 11 through the pads on the top surfaces of the chips. Figure 1B In the illustrated embodiment, the first chip 12-1 and the second chip 12-2 are placed on the substrate in a flip-chip manner, and the pads on the top surfaces thereof are electrically connected to the metal traces on the substrate through the connecting material 17. In one embodiment, the connecting material 17 includes copper pillars. In another embodiment, the connecting material 17 includes solder balls.

[0026] The metal pillar 13 is disposed at the edge of the substrate 11, and the metal pillar 13 is mounted on the substrate 11 by an adhesive 16. In one embodiment, the metal pillar 13 comprises a cylindrical copper block.

[0027] A passive component 15 is also mounted on the substrate 11 . The passive component 15 may be placed between the first chip 12 - 1 and the second chip 12 - 2 , and between the chip and the metal pillar 13 .

[0028] The molding compound 14 is used to wrap the first chip 12 - 1 , the second chip 12 - 2 , and the metal pillar 13 , and expose the top surface of the metal pillar 13 to the outside of the molding compound 14 as a solder pad on the top surface of the first package body.

[0029] The inductor component is stacked on the pad on the top surface of the first package body. In one embodiment, the inductor component is mounted on the top surface of the metal pillar 13 by an adhesive.

[0030] Figure 2A and Figure 2B They are respectively a perspective view and an external view of the first package body in the package structure 100. Figure 2A As shown, in the embodiment shown, the first package body includes four metal pillars, namely: a first metal pillar 13-1, a second metal pillar 13-2, a third metal pillar 13-3 and a fourth metal pillar 13-4. The first chip 12-1 and the second chip 12-2 are arranged side by side in the middle of the substrate 11, the first metal pillar 13-1 and the second metal pillar 13-2 are arranged on one side of the first chip 12-1 close to the edge of the substrate 11, and the third metal pillar 13-3 and the fourth metal pillar 13-4 are arranged on one side of the second chip 12-2 close to the edge of the substrate 11.

[0031] In one embodiment, the first chip and the second chip both include a control stage and a power stage. As shown in the figure, the 12-1-a portion of the first chip 12-1 is its control stage, and the rest is its power stage; the 12-2-a portion of the second chip 12-2 is its control stage, and the rest is its power stage. The power stage in each chip includes two power switches, wherein the common end of the two power switches is a switch pad on the top surface of the chip.

[0032] The first metal pillar 13-1 is placed near the middle of the first chip 12-1, the second metal pillar 13-2 is placed near one end of the power stage in the first chip 12-1, the third metal pillar 13-3 is placed near the middle of the second chip 12-2, and the fourth metal pillar 13-1 is placed near one end of the power stage of the second chip 12-2. The first metal pillar 13-1 is electrically connected to the switch pad of the first chip 12-1 through the substrate 11; the second metal pillar 13-2 is electrically connected to the output pin at the bottom of the substrate 11; the third metal pillar 13-3 is electrically connected to the switch pad of the second chip 12-2 through the substrate 11; and the fourth metal pillar 13-4 is electrically connected to the output pin at the bottom of the substrate 11. The plastic encapsulation material 14 wraps the first metal pillar 13-1, the second metal pillar 13-2, the third metal pillar 13-3 and the fourth metal pillar 13-4, and exposes the top surfaces of the four metal pillars to the outside of the plastic encapsulation material 14 as pads on the top surface of the first package body, such as Figure 2B An external view of the first package body is shown.

[0033] Continue to see Figure 2A , the first package also includes a plurality of passive components 15, and the passive components 15 include one or more of resistors, capacitors and inductors. In one embodiment, the passive component 15 mainly includes an input capacitor 15-1. The input capacitor 15-1 is placed in the area between the first chip 12-1 and the second chip 12-2 and in the area between the third metal column 13-3 and the fourth metal column 13-4. The input capacitor 15-1 is placed as close as possible to the switch pad of the chip and one end of the power stage, so that the parasitic inductance of the loop can be reduced to the greatest extent, thereby reducing the voltage spike caused by the loop inductance.

[0034] In addition to the input capacitor 15 - 1 , the passive component 15 also includes other passive components 15 - 2 that need to be placed, including capacitors between the supply voltage and the reference ground, bootstrap capacitors, and related resistors, etc. All passive components 15 are completely wrapped in the first package by the plastic packaging material 14 .

[0035] In one embodiment, Figure 1A The inductor assembly includes a first coil and a second coil, and the two ends of the first coil are respectively attached to the top surface of the first metal column 13-1 and the top surface of the second metal column 13-2 through an adhesive 16; the two ends of the second coil are respectively attached to the top surface of the third metal column 13-3 and the top surface of the fourth metal column 13-4 through an adhesive 16. In one embodiment, the inductor assembly also includes a magnetic core and an insulating substrate.

[0036] Figure 3A -D is a process flow chart of preparing a packaging structure 100 according to an embodiment of the present invention. It should be understood by those skilled in the art that Figures 3A to 3D The cross-sectional schematic diagram only shows some process stages.

[0037] refer to Figure 3A As shown in FIG. 1 , a passive component 15 is mounted on a prepared substrate 11 by an adhesive. In one embodiment, the adhesive includes solder, such as solder paste.

[0038] refer to Figure 3B As shown in FIG. 1 , the metal pillar 13 is mounted by an adhesive, which in one embodiment includes solder, such as solder paste.

[0039] refer to Figure 3C As shown in the figure, the first chip 12-1 and the second chip 12-2 are invertedly mounted on the substrate 11 by an adhesive. In one embodiment, the adhesive includes copper pillars or solder balls. The first chip 12-1 and the second chip 12-2 are mounted on the substrate 11 by reflow soldering.

[0040] Continue to refer Figure 3D The auxiliary film is poured to form a plastic packaging material 14, while ensuring that the top surface of the metal column 13 is exposed on the upper surface of the first plastic packaging body. Then, the inductor component is installed on the first packaging body to form a packaging structure 100.

[0041] Figure 4 The figure shows a cross-sectional view of a dual-phase switching converter packaging structure 200 according to another embodiment of the present invention. Compared with the packaging structure 100, in the packaging structure 200, the metal column is schematically shown as an L-shaped block metal 23. As shown in the figure, the L-shaped block metal 23 has a top surface S1, a middle contact surface S2 and a bottom surface S3 from top to bottom. The top surface S1 of the L-shaped block metal 23 is exposed to the outside of the plastic packaging material 14 and is used to connect the inductor component; the middle contact surface S2 of the L-shaped block metal 23 is adhered to the bottom surface of the chip through the insulating glue 18; the bottom surface S3 of the L-shaped block metal 23 is connected to the substrate through an adhesive. Among them, the insulating glue 18 is used to isolate the bottom surface of the chip from the L-shaped block metal 23. The middle contact surface S2 of the L-shaped block metal 23 contacts the bottom surface of the chip, which allows the chip to dissipate heat through the L-shaped block metal 23, reduces the operating temperature of the chip, and is conducive to system stability.

[0042] In one embodiment, since the first metal pillar 13-1 and the third metal pillar 13-3 are electrically connected to the switch pads of the first chip 12-1 and the second chip 12-2 respectively, and the switch pad is the common end of the two power switch tubes and generates a large amount of heat, the first metal pillar 13-1 and the third metal pillar 13-3 connected to the switch pad can be selected to be set as L-shaped block metal 23, while the second metal pillar 13-2 and the fourth metal pillar 13-4 remain as columnar metal. Figure 5 Shows Figure 4 The external view of the first package body of the dual-phase switching converter package structure 200 is as shown in FIG. Figure 5As shown, the top surface areas of the first metal pillar 13-1 and the third metal pillar 13-3 are larger than the top surface areas of the second metal pillar 13-2 and the fourth metal pillar 13-4, and the top surfaces of the first metal pillar 13-1 and the third metal pillar 13-3 are convex to increase the heat dissipation area of ​​the first package.

[0043] Figure 6 FIG. 1 is a cross-sectional view of a dual-phase switching converter package structure 300 according to another embodiment of the present invention. Compared with the package structure 100, the first package body of the package structure 300 further includes a C-shaped copper block 19. The C-shaped copper block 19 has a top surface S4, a first bottom surface S5, and a second bottom surface S6. The top surface S4 of the C-shaped copper block 19 is exposed outside the plastic package 14 (see FIG. 1 ). Figure 7 (External view of the first package body of the dual-phase switching converter package structure 300 shown in FIG. 1 ), the first bottom surface S5 of the C-shaped copper block 19 is adhered to the bottom surface of the first chip 12-1 through the conductive adhesive 28, and the second bottom surface S6 of the C-shaped copper block 19 is adhered to the bottom surface of the second chip 12-2 through the conductive adhesive 28. In one embodiment, the top surface S4 of the C-shaped copper block 19 can be further connected to the inductor component through the heat dissipation adhesive 38 to facilitate the heat dissipation of the chip. It can be understood that the top surface S4 of the C-shaped copper block 19 here is not connected to the power terminal of the inductor component, but is adhered to the insulating substrate of the inductor component. In another embodiment, a heat dissipation metal sheet can be mounted on the outer surface of the inductor component, and the metal sheet can be connected to the top surface S4 of the C-shaped copper block 19 through the heat dissipation adhesive 38 to further enhance the heat dissipation effect.

[0044] It should be noted that in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "setting" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances; the drawings in the embodiments are used to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations.

[0045] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A packaging structure, characterized in that: include: substrate; A first chip is mounted on the substrate, wherein the first chip has a switch pad; A second chip is mounted on the substrate, wherein the second chip has a switch pad; A first metal column is mounted on the substrate and electrically connected to the switch pad of the first chip through the substrate; A second metal column is mounted on the substrate and electrically connected to an output pin of the substrate; A third metal column is mounted on the substrate and electrically connected to the switch pad of the second chip through the substrate; a fourth metal column, mounted on the substrate and electrically connected to the output pin of the substrate; A plastic encapsulation material is used to encapsulate the first chip, the second chip, the first metal column, the second metal column, the third metal column and the fourth metal column, and expose the top surfaces of the first metal column, the second metal column, the third metal column and the fourth metal column to the outside of the plastic encapsulation material; The inductor component is stacked on the top surfaces of the first metal column, the second metal column, the third metal column and the fourth metal column.

2. The packaging structure according to claim 1, characterized in that: The first chip and the second chip are arranged side by side in the middle of the substrate, the first metal column and the second metal column are arranged on the side of the first chip close to the edge of the substrate, and the third metal column and the fourth metal column are arranged on the side of the second chip close to the edge of the substrate.

3. The packaging structure according to claim 2, characterized in that: The first metal column is placed near the middle of the first chip, the second metal column is placed near the power level end of the first chip, the third metal column is placed near the middle of the second chip, and the fourth metal column is placed near the power level end of the second chip.

4. The packaging structure according to claim 1, characterized in that: Further including: A plurality of input capacitors are arranged in a region between the first chip and the second chip and in a region between the third metal column and the fourth metal column, and the plurality of input capacitors are completely wrapped by a plastic packaging material.

5. The packaging structure according to claim 1, characterized in that: Further including: The passive component is arranged on the substrate and is completely wrapped by the plastic packaging material.

6. The packaging structure according to claim 1, characterized in that: The first chip and the second chip are both flip-chip mounted on a substrate.

7. The packaging structure according to claim 1, characterized in that: The first metal column and the third metal column are L-shaped block metals, and the L-shaped block metal has a top surface, a middle contact surface and a bottom surface from top to bottom; the top surface of the first metal column is exposed to the outside of the plastic packaging material, the middle contact surface of the first metal column is adhered to the bottom surface of the first chip through an insulating glue, and the bottom surface of the first metal column is connected to the substrate through an adhesive; the top surface of the third metal column is exposed to the outside of the plastic packaging material, the middle contact surface of the third metal column is adhered to the bottom surface of the second chip through an insulating glue, and the bottom surface of the third metal column is connected to the substrate through an adhesive.

8. The packaging structure according to claim 1, characterized in that: The packaging structure further includes: A C-shaped copper block, wherein the C-shaped copper block has a top surface, a first bottom surface, and a second bottom surface. The top surface of the C-shaped copper block is exposed outside the plastic packaging material, the first bottom surface of the C-shaped copper block is adhered to the bottom surface of the first chip through a conductive adhesive, and the second bottom surface of the C-shaped copper block is adhered to the bottom surface of the second chip through a conductive adhesive.

9. The packaging structure according to claim 8, characterized in that: The top surface of the C-shaped copper block is connected to the inductor assembly through a heat dissipation adhesive.

10. The packaging structure according to claim 1, characterized in that: The first chip and the second chip each include two power switches, wherein a common end of the two power switches is a switch pad of the corresponding chip.

11. The packaging structure according to claim 1, characterized in that: The inductor assembly includes a first coil and a second coil, wherein two ends of the first coil are respectively attached to the top surface of the first metal column and the top surface of the second metal column by adhesive; and two ends of the second coil are respectively attached to the top surface of the third metal column and the top surface of the fourth metal column by adhesive.

12. A packaging method for a dual-phase switching converter, characterized in that: include: providing a substrate; Mounting a first chip and a second chip on a substrate, wherein both the first chip and the second chip have a switch pad; Mounting a first metal column, a second metal column, a third metal column and a fourth metal column on a substrate by means of an adhesive, wherein the first metal column is electrically connected to a switch pad of a first chip through the substrate, the third metal column is electrically connected to a switch pad of a second chip through the substrate, and the second metal column and the fourth metal column are electrically connected to an output pin of the substrate; The first chip, the second chip, the first metal column, the second metal column, the third metal column and the fourth metal column are encapsulated by a molding compound, and the top surfaces of the first metal column, the second metal column, the third metal column and the fourth metal column are exposed to the outside of the molding compound; The inductor component is mounted on the top surfaces of the first metal pillar, the second metal pillar, the third metal pillar and the fourth metal pillar.

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