CN119812129A - Packaging structure and method of dual-phase switching converter - Google Patents

Abstract

The present invention provides a packaging structure and method for a dual-phase switching converter. The packaging structure includes a first packaging body and an inductor assembly, wherein the inductor assembly is stacked and installed on the top of the first packaging body. The first packaging body includes a substrate and two chips, a passive component and four metal pillars installed on the substrate. The two chips each include two power switching devices, and the common end of the two switching devices serves as a switch pad of the chip. The metal pillar is used to electrically connect one end of the two coils in the inductor assembly to the switch pad of the chip through the substrate, and to electrically connect the other end of the two coils in the inductor assembly to the output pin of the substrate. The packaging structure proposed by the present invention occupies a small area and space position on the PCB, and has good heat dissipation performance, and is suitable for high-current applications of dual-phase switching converters.

Description

Packaging structure and method of biphase switching converter

Technical Field

The invention relates to the field of integrated circuit packaging, in particular to a packaging structure and method of a dual-phase switch converter.

Background

With the development of miniaturization and multifunction of electronic devices, the types and numbers of chips and passive components that need to be integrated and packaged together are increasing, so the requirements for the packaging structure and the packaging process are increasing. The semiconductor package provides support for the integrated circuit chip or semiconductor wafer, provides protection from environmental effects, and can be mounted on and interconnected with external components.

The power switch converter module at least comprises an integrated wafer with power switch devices and controller functions, and passive components such as an input capacitor, an output capacitor, an inductor and the like. In a bi-phase converter, the number of die and passive components is doubled, the size of area and volume is considered for the assembly of these components into a single package, and heat dissipation is an important aspect to be considered.

Disclosure of Invention

Aiming at the problems existing in the prior art, a packaging structure of a double-phase switch converter and a preparation method thereof are provided,

The first aspect of the present invention provides a packaging structure of a dual-phase switching converter, which comprises an inductance component, a substrate, a first wafer, a second wafer and four metal columns, wherein the first wafer, the second wafer and the four metal columns are mounted on the substrate. The first wafer and the second wafer are respectively provided with a switch bonding pad, the first metal column is electrically connected with the switch bonding pad of the first wafer through the substrate, the second metal column is electrically connected with the output pin of the substrate, the third metal column is electrically connected with the switch bonding pad of the second wafer through the substrate, and the fourth metal column is electrically connected with the output pin of the substrate. The plastic package material wraps the first wafer, the second wafer and the four metal posts, and the top surfaces of the four metal posts are exposed outside the plastic package material. The inductance assembly is stacked on the top surfaces of the four metal posts.

The second aspect of the present invention proposes a packaging method for a bi-phase switching converter. The method comprises the steps of providing a substrate, mounting a first wafer and a second wafer on the substrate, wherein the first wafer and the second wafer are provided with switch pads, attaching 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 with the switch pad of the first wafer through the substrate, the third metal column is electrically connected with the switch pad of the second wafer through the substrate, the second metal column and the fourth metal column are electrically connected with output pins of the substrate, wrapping the first wafer, the second wafer, the first metal column, the second metal column, the third metal column and the fourth metal column through plastic packaging materials, exposing 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 packaging materials, and mounting an inductance component on the top surfaces of the first metal column, the second metal column, the third metal column and the fourth metal column.

Compared with the prior art, the packaging structure prepared by adopting the technical scheme occupies small area and space of the PCB, has good heat dissipation performance, and is suitable for high-current occasions of the double-phase switch converter.

Drawings

FIG. 1A illustrates an overall diagram of a package structure 100 for a bi-phase switching converter, according to one embodiment of the present invention;

fig. 1B shows a cross-sectional view of a package structure 100 of a bi-phase switching converter, according to one embodiment of the invention.

FIG. 2A illustrates a perspective view of a first package in package structure 100, according to one embodiment of the present invention;

FIG. 2B illustrates an exterior view of a first package in the package structure 100, according to one embodiment of the invention;

FIGS. 3A-D are process flow diagrams for preparing a package structure 100 according to one embodiment of the present invention;

fig. 4 shows a cross-sectional view of a bi-phase switching converter package structure 200 according to another embodiment of the present invention;

Fig. 5 shows an external view of a first package of a bi-phase switching converter package structure 200, according to one embodiment of the invention;

fig. 6 shows a cross-sectional view of a bi-phase switching converter package structure 200 according to yet another embodiment of the present invention;

fig. 7 shows an external view of a first package of the bi-phase switching converter package structure 200, according to one embodiment of the invention.

The reference numerals are 11-base plate, 12-1-first wafer, 12-2-second wafer, 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 package material, 15-passive element, 15-1-input capacitor, 15-2-other passive element, 16-adhesive, 17-connecting material, 18-insulating glue, 28-conductive glue, 38-heat dissipation adhesive, 12-1-a-control level of the first wafer 12-1, 12-2-a-control level of the second wafer 12-2.

Detailed Description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar modules or modules having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the application. On the contrary, the embodiments of the application include all alternatives, modifications and equivalents as may be included within the spirit and scope of the appended claims.

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that like reference numerals and letters refer to like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures. In the description of the present invention, it should be noted that, if the terms "upper", "lower", "inner", "outer", and the like indicate an azimuth or a positional relationship based on the azimuth or the positional relationship shown in the drawings, or the azimuth or the positional relationship in which the inventive product is conventionally put in use, it is merely for convenience of describing the present invention and simplifying the description, and it is not indicated or implied that the apparatus or element referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus it should not be construed as limiting the present invention. The terms "first," "second," and the like, if any, are used solely for distinguishing between descriptions and should not be construed as indicating or implying a relative importance.

Furthermore, references throughout this specification to "one embodiment," "an embodiment," "one example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "in one embodiment," "in an embodiment," "one example," or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combination and/or sub-combination in one or more embodiments or examples.

Fig. 1A and 1B illustrate an overall view and a cross-sectional view of a package structure 100 of a dual-phase switching converter according to an embodiment of the present invention, wherein fig. 1B is a cross-sectional view along A-A' direction in fig. 1A. As shown in fig. 1A, the package structure includes a first package body and an inductance component, wherein the inductance component is vertically mounted on the first package body. Specifically, referring to fig. 1B, the first package includes a substrate 11, a first die 12-1, a second die 12-2, metal posts 13, a molding compound 14, and a passive component 15.

The substrate 11 may be a molded part including a dielectric and patterned printed metal traces, and the dielectric may be formed of a non-conductive plastic or resin material. The base plate 11 has chip pins at the bottom, which can be mounted on and interconnected with external components, such as a printed circuit board PCB. The first wafer and the second wafer are adhered on the substrate and are electrically connected with the chip pins at the bottom of the substrate through the metal traces of the substrate.

The first wafer 12-1 and the second wafer 12-2 are mounted on a substrate. The top surfaces of the first wafer 12-1 and the second wafer 12-2 are provided with wafer pads, and the internal components of the first wafer 12-1 and the second wafer 12-2 are connected with the substrate 11 through the pads on the top surfaces of the wafers. In the embodiment shown in fig. 1B, the first die 12-1 and the second die 12-2 are flip-chip mounted on a substrate with pads on the top surface thereof electrically connected to metal traces on the substrate by the connecting material 17. In one embodiment, the connection material 17 comprises copper pillars. In yet another embodiment, the connection material 17 comprises solder balls.

The metal posts 13 are arranged at the edge of the substrate 11, and the metal posts 13 are attached to the substrate 11 by an adhesive 16. In one embodiment, the metal posts 13 comprise cylindrical copper blocks.

Also disposed on the substrate 11 are passive components 15 which may be placed between the first wafer 12-1 and the second wafer 12-2, and between the wafer and the metal posts 13.

The molding compound 14 is used for wrapping the first wafer 12-1, the second wafer 12-2, and the metal pillars 13, and exposing the top surfaces of the metal pillars 13 to the outside of the molding compound 14 to serve as bonding pads of the top surface of the first package.

The inductor assembly is stacked on the pads on the top surface of the first package, and in one embodiment, the inductor assembly is attached to the top surface of the metal posts 13 by an adhesive.

Fig. 2A and 2B are a perspective view and an external view, respectively, of a first package body in the package structure 100. In the illustrated embodiment, the first package includes four metal posts, a first metal post 13-1, a second metal post 13-2, a third metal post 13-3, and a fourth metal post 13-4, respectively, as shown in FIG. 2A. The first wafer 12-1 and the second wafer 12-2 are arranged in parallel in the middle of the substrate 11, the first metal column 13-1 and the second metal column 13-2 are arranged on one side of the first wafer 12-1 near the edge of the substrate 11, and the third metal column 13-3 and the fourth metal column 13-4 are arranged on one side of the second wafer 12-2 near the edge of the substrate 11.

In one embodiment, the first wafer and the second wafer each include a control level and a power level. As shown, the portion 12-1-a of the first wafer 12-1 is at its control level and the remainder is at its power level, and the portion 12-2-a of the second wafer 12-2 is at its control level and the remainder is at its power level. The power stage in each die includes two power switches, wherein the common terminal of the two power switches is a switch pad on the top surface of the die.

The first metal pillar 13-1 is placed near the middle of the first wafer 12-1, the second metal pillar 13-2 is placed near one end of the power stage in the first wafer 12-1, the third metal pillar 13-3 is placed near the middle of the second wafer 12-2, and the fourth metal pillar 13-1 is placed near one end of the power stage in the second wafer 12-2. The first metal column 13-1 is electrically connected with the switch pad of the first wafer 12-1 through the substrate 11, the second metal column 13-2 is electrically connected with the output pin at the bottom of the substrate 11, the third metal column 13-3 is electrically connected with the switch pad of the second wafer 12-2 through the substrate 11, and the fourth metal column 13-4 is electrically connected with the output pin at the bottom of the substrate 11. The molding compound 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 molding compound 14 as pads of the top surface of the first package body, as shown in the external view of the first package body of fig. 2B.

With continued reference to fig. 2A, a plurality of passive elements 15 are further included in the first package, the passive elements 15 including one or more of a resistor, a capacitor, and an inductor. In one embodiment, the passive element 15 includes primarily an input capacitance 15-1. The input capacitance 15-1 is disposed in a region between the first wafer 12-1 and the second wafer 12-2, and in a region between the third metal pillar 13-3 and the fourth metal pillar 13-4. The input capacitance 15-1 is placed as close as possible to the switch pad of the die and to one end of the power stage, which minimizes the loop parasitic inductance and thus voltage spikes caused by the loop inductance.

In addition to the input capacitance 15-1, the passive element 15 also includes other passive components 15-2 that need to be placed, the passive components 15-2 including a capacitance between the supply voltage and the reference ground, a bootstrap capacitance, and associated resistances, etc. All the passive components 15 are completely enclosed in the first package by the molding compound 14.

In one embodiment, the inductance assembly in fig. 1A 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 pillar 13-1 and the top surface of the second metal pillar 13-2 through an adhesive 16, and two ends of the second coil are respectively attached to the top surface of the third metal pillar 13-3 and the top surface of the fourth metal pillar 13-4 through an adhesive 16. In one embodiment, the inductance assembly further comprises a magnetic core and an insulating matrix.

Fig. 3A-D are process flow diagrams for preparing a package structure 100 according to an embodiment of the present invention. It will be appreciated by those skilled in the art that the cross-sectional schematic diagrams of fig. 3A through 3D only illustrate a partial flow stage.

Referring to the illustration of fig. 3A, passive component 15 is mounted on prepared substrate 11 by an adhesive, which in one embodiment comprises solder, such as solder paste.

Referring to the illustration of fig. 3B, the metal posts 13 are mounted by an adhesive, which in one embodiment comprises solder, such as solder paste.

Referring to the illustration of fig. 3C, the first and second wafers 12-1 and 12-2 are mounted upside down on the substrate 11 by an adhesive, which in one embodiment includes copper posts or solder balls, and the first and second wafers 12-1 and 12-2 are mounted on the substrate 11 by reflow soldering.

With continued reference to fig. 3D, the molding compound 14 is formed by pouring through the auxiliary film while ensuring that the top surface of the metal pillar 13 is exposed at the upper surface of the first molding compound. The inductor assembly is then mounted on the first package to form the package structure 100.

Fig. 4 is a cross-sectional view of a dual phase switching converter package structure 200 according to another embodiment of the present invention. In contrast to the package structure 100, in the package structure 200, the metal pillars are illustrated as L-shaped bulk metals 23. As shown, the L-shaped bulk metal 23 has a top surface S1, an intermediate 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 outside the plastic package material 14 and is used for connecting an inductance component, the middle contact surface S2 of the L-shaped block metal 23 is adhered to the bottom surface of a wafer through the insulating glue 18, and the bottom surface S3 of the L-shaped block metal 23 is connected with a substrate through an adhesive. Wherein the insulating glue 18 is used to isolate the bottom surface of the wafer from the L-shaped bulk metal 23. The middle contact surface S2 of the L-shaped block metal 23 is in contact with the bottom surface of the wafer, so that the wafer can dissipate heat through the L-shaped block metal 23, the working temperature of the wafer is reduced, and the system is stable.

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 wafer 12-1 and the second wafer 12-2, respectively, which are common ends of the two power switching transistors, and the amount of heat generated is large, the first metal pillar 13-1 and the third metal pillar 13-3 connected to the switch pads may be selectively provided as the L-shaped bulk metal 23, while the second metal pillar 13-2 and the fourth metal pillar 13-4 remain as the columnar metal. Fig. 5 shows an external view of the first package body of the dual-phase switching converter package structure 200 in fig. 4, and as shown in fig. 5, the top surface area of the first metal pillar 13-1 and the third metal pillar 13-3 is larger than the top surface area 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 body.

Fig. 6 is a cross-sectional view of a dual phase switching converter package structure 300 according to yet another embodiment of the present invention. The first package of the package structure 300 further includes a C-shaped copper block 19 therein, as compared to the package structure 100. 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 molding compound 14 (see the external view of the first package body of the dual-phase switch converter package structure 300 shown in fig. 7), the first bottom surface S5 of the C-shaped copper block 19 is adhered to the bottom surface of the first wafer 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 wafer 12-2 through the conductive adhesive 28. In one embodiment, the top surface S4 of the C-shaped copper block 19 may be further connected to the inductor assembly by a heat dissipating adhesive 38 to facilitate heat dissipation from the die. It will be appreciated that the top surface S4 of the C-shaped copper block 19 is not connected to the electrical terminals of the inductor assembly, but is glued to the dielectric substrate of the inductor assembly. In another embodiment, the outer surface of the inductance assembly may be attached with a heat dissipating metal sheet, which may be connected to the top surface S4 of the C-shaped copper block 19 by a heat dissipating adhesive 38 to further enhance the heat dissipation effect.

It should be noted that, in the description of the embodiments of the present invention, unless explicitly specified and limited otherwise, the terms "disposed" and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, integrally connected, directly connected, or indirectly connected through an intermediate medium. The drawings in the embodiments are used to clearly and completely describe the technical solutions in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention and not all embodiments. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

While embodiments of the present application have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the application, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the application.

Claims (12)

1. A package structure, comprising:

A substrate;

A first wafer mounted on the substrate, the first wafer having a switch pad;

A second wafer mounted on the substrate, the second wafer having a switch pad;

The first metal column is arranged on the substrate and is electrically connected with the switch bonding pad of the first wafer through the substrate;

The second metal column is arranged on the substrate and is electrically connected with the output pin of the substrate;

the third metal column is arranged on the substrate and is electrically connected with the switch bonding pad of the second wafer through the substrate;

The fourth metal column is arranged on the substrate and is electrically connected with the output pin of the substrate;

The plastic packaging material is used for wrapping the first wafer, the second wafer, 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 packaging material;

and the inductance 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 package structure of claim 1, wherein the first die and the second die are disposed in parallel in a middle portion of the substrate, the first metal pillar and the second metal pillar are disposed on a side of the first die adjacent to the edge of the substrate, and the third metal pillar and the fourth metal pillar are disposed on a side of the second die adjacent to the edge of the substrate.

3. The package structure of claim 2, wherein the first metal pillar is disposed proximate a middle portion of the first die, the second metal pillar is disposed proximate a power level end of the first die, the third metal pillar is disposed proximate a middle portion of the second die, and the fourth metal pillar is disposed proximate a power level end of the second die.

4. The package structure of claim 1, further comprising:

the input capacitors are arranged in the area between the first wafer and the second wafer and the middle area of the third metal column and the fourth metal column, and the input capacitors are completely wrapped by the plastic package material.

5. The package structure of claim 1, further comprising:

And the passive element is arranged on the substrate and is completely wrapped by the plastic packaging material.

6. The package structure of claim 1, wherein the first and second dies are flip-chip mounted on a substrate.

7. The packaging structure of claim 1, wherein the first metal column and the third metal column are L-shaped block metals, the L-shaped block metals are provided with 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 outside the plastic packaging material, the middle contact surface of the first metal column is adhered to the bottom surface of the first wafer through insulating glue, the bottom surface of the first metal column is connected with the substrate through an adhesive, the top surface of the third metal column is exposed outside the plastic packaging material, the middle contact surface of the third metal column is adhered to the bottom surface of the second wafer through insulating glue, and the bottom surface of the third metal column is connected with the substrate through the adhesive.

8. The package structure according to claim 1, the packaging structure is characterized by further comprising:

The C-shaped copper block is provided with 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 package material, the first bottom surface of the C-shaped copper block is adhered to the bottom surface of the first wafer through conductive adhesive, and the second bottom surface of the C-shaped copper block is adhered to the bottom surface of the second wafer through conductive adhesive.

9. The package structure of claim 8, wherein the top surface of the C-shaped copper block is connected to the inductor assembly by a heat dissipating adhesive.

10. The package structure of claim 1, wherein the first die and the second die each comprise two power switches, wherein a common terminal of the two power switches is a switch pad of the corresponding die.

11. The package structure of claim 1, wherein the inductance assembly comprises a first coil and a second coil, two ends of the first coil are respectively attached to the top surface of the first metal pillar and the top surface of the second metal pillar by an adhesive, and two ends of the second coil are respectively attached to the top surface of the third metal pillar and the top surface of the fourth metal pillar by an adhesive.

12. A packaging method for a bi-phase switching converter, comprising:

providing a substrate;

Mounting a first wafer and a second wafer on a substrate, wherein the first wafer and the second wafer each have a switch pad;

Attaching a first metal column, a second metal column, a third metal column and a fourth metal column on a substrate through an adhesive, wherein the first metal column is electrically connected with a switch bonding pad of a first wafer through the substrate, the third metal column is electrically connected with a switch bonding pad of a second wafer through the substrate, and the second metal column and the fourth metal column are electrically connected with a substrate output pin;

Wrapping the first wafer, the second wafer, the first metal column, the second metal column, the third metal column and the fourth metal column by adopting a plastic package material, 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 package material;

the inductor assembly is mounted on top of the first, second, third and fourth metal posts.