CN111987088B - Organic substrate embedding packaging structure integrating antenna and radio frequency front end - Google Patents

Abstract

An organic substrate embedded package structure integrating an antenna and a radio frequency front end, comprising: an antenna module; and a radio frequency front end module disposed below the antenna module, the radio frequency front end module comprising: the first core board comprises at least one through groove inside; at least one active chip, one side surface of which is an active surface and the other side surface of which is back metal, wherein the active chip is embedded in the through groove of the first core board; the first dielectric layer is arranged below the first core plate, and a through groove is arranged at a position corresponding to the through groove in the first core plate; the second core board is arranged below the first dielectric layer, and a plurality of component bonding pads are arranged on the upper surface of the second core board; one side of the active surface of the active chip faces downwards and is inversely arranged on a surface element device bonding pad on the second core plate; and the second dielectric layer is arranged above the first core plate, and a plurality of metallized blind holes are arranged in the second dielectric layer in a penetrating manner.

Description

Organic substrate embedded package structure with integrated antenna and RF front end

technical field

The invention relates to the technical field of semiconductor packaging, in particular to an organic substrate embedded packaging structure integrating a millimeter wave antenna and a radio frequency front end.

Background technique

In order to improve the integration level, the International Semiconductor Technology Development Route Organization proposes to surpass Moore's Law, aiming to integrate processors, memory, radio frequency modules, digital modules, analog modules, optoelectronic modules, sensing modules, etc. in a single package to achieve system-level packaging (System in Package, SiP), if the antenna is also integrated in a system-in-package, it is called an antenna-in-package (Antenna in Package, AiP).

At present, the research on AiP mainly focuses on the integration of single-chip transceiver and antenna. However, the integration of multi-chip RF front-end and antenna array faces the following technical problems: the millimeter-wave chips used in the RF front-end are mostly based on compound semiconductor technology, and the active surface Surface transmission lines, inductance-capacitor air bridges and back grounding requirements limit chip packaging to wire bonding, but with the increase of operating frequency, the parasitic effect of bonding wires becomes more and more obvious; at the same time, electronic products have thinner and smaller packages. The demand for automation continues to increase, but the thin and light packaging structure limits the thickness of the antenna substrate, which limits the improvement of antenna performance; in addition, when the antenna is integrated with the RF front-end, the active chips and The problem of electromagnetic interference is particularly serious; in addition, most of the passive components are surface-mounted on the motherboard, occupying the area of the RF front-end module.

Therefore, based on the above problems in the prior art, there is an urgent need to develop an antenna-level packaging structure for compound semiconductor active chips that is light, thin, miniaturized, has good electromagnetic compatibility and high performance.

SUMMARY OF THE INVENTION

(1) Technical problems to be solved

The present invention proposes an organic substrate embedded packaging structure integrating an antenna and a radio frequency front end to at least partially meet the requirements of miniaturization, thinness and high performance of an antenna-level package based on compound semiconductor active chips in the millimeter wave band.

(2) Technical solutions

In one aspect of the present invention, an organic substrate embedded package structure integrating an antenna and a radio frequency front end includes: an antenna module; and a radio frequency front end module placed under the antenna module, the radio frequency front end module comprising: a No. 1 core board, the interior includes at least one through groove; at least one active chip, one side surface is the active surface, the other side surface is the back metal, the active chip is embedded in the through groove of the No. 1 core board; No. 1 The dielectric layer is placed under the No. 1 core board, and a through slot is provided in the corresponding position of the through groove in the No. 1 core board; ; wherein, the active surface of the active chip faces down, and is flip-mounted on the surface component pads of the No. 2 core board; the No. 2 dielectric layer is placed above the No. 1 core board.

In a further solution, the RF front-end module further includes at least one surface-mount passive component, and the surface-mount passive component has a pad on one side and is embedded in the through groove of the No. 1 core board, in which there are The side of the pad is facing down, and it is flipped over the component pads on the surface of the No. 2 core board.

In a further solution, the RF front-end module further includes at least one single-layer capacitor, the single-layer capacitor is embedded in the through groove of the No. on the plate.

In a further solution, the side wall of the through groove of the No. 1 core board is further plated with a No. 1 metal layer, and a dielectric layer is further arranged between the No. 1 metal layer and the active chip.

In a further solution, the No. 2 core board is provided with a plurality of electromagnetic shielding hole grids, and the No. 1 metal layer forms a metal shielding cavity.

In a further solution, the active chip, the embedded surface-mount passive component and the single-layer capacitor are interconnected with the peripheral circuit through metallized blind vias in the No. 2 core board.

In a further solution, the RF front-end module is further provided with a plurality of metallized through holes.

In a further solution, the antenna module includes: at least one antenna unit; a periodic metal structure; a No. 2 metal layer, the periodic metal structure and No. 2 metal layer jointly serve as an antenna reflection plane; The antenna module further comprises: a No. 3 core board, on which the periodic metal structure is electroplated; a No. 3 dielectric layer is arranged between the No. 3 core board and the No. 2 metal layer; the No. 4 dielectric layer is configured on the antenna unit and periodic metallic structures.

In a further solution, the metal on the backside of the active chip is connected to the second metal layer through metallized blind holes in the second dielectric layer.

In a further solution, the other electrode of the single-layer capacitor is connected to the second metal layer through the metallized blind hole of the second dielectric layer.

In a further solution, the periodic metal structure is an electromagnetic structure, which has in-phase reflection characteristics within a set millimeter wave band.

In a further solution, the antenna unit and the radio frequency front-end module are placed vertically, and are interconnected through metallized through holes, so as to reduce electromagnetic interference between the antenna module and the radio frequency front-end module.

In a further solution, the dielectric layer is formed by pressing the prepreg and then curing.

In a further solution, a plurality of solder balls are also arranged on the lower surface of the No. 2 core board.

In another aspect of the present invention, a preparation method of an organic substrate embedded package structure integrating an antenna and a radio frequency front end is also provided, including:

Pattern the surface of the No. 2 core board, including component pads, metallized blind hole capture pads, and interconnect lines.

The core board is placed on a high-temperature bonding table, metal bumps are processed on the component pads by a wire bonding machine, and the metal bumps are flattened to approximately the same height.

Put the active surface of the active chip and the surface-mounted passive component with the pad side down, and flip them on the metal bumps on the surface of the No. 2 core board by hot pressing. At the same time, the single-layer capacitor is also Flip-chip on the corresponding metal bumps on the upper surface of the core board;

The active chips, surface-mounted passive components and single-layer capacitors are embedded in the through-slots milled in the No. 1 core board, and metal copper is plated on the sidewalls of the through-slots. At the same time, the metal coating on the upper and lower surfaces of the core board passes light engraving;

Drill a slot with a slightly larger area than the through slot in the No. 1 core board on the No. 1 dielectric layer below the No. 1 core board; The No. 2 core boards are stacked together for vacuum lamination. After high temperature curing, the two prepregs are transformed into No. 2 dielectric layer and No. 1 dielectric layer.

Process metallized blind holes in the second dielectric layer, process metallized through holes in the whole structure, partially metallized blind holes are used for electromagnetic shielding, partially metallized blind holes are used for electrical interconnection, and metallized through holes are used for electromagnetic shielding and interconnects between different metal ground planes. After that, the upper surface of the No. 2 dielectric layer on the No. 1 core board is plated with a No. 2 metal layer, which is used as a metal ground plane for the electronic components in the RF front-end module.

The upper surface of the No. 3 core board is electroplated with a layer of periodic metal structure, which together with the No. 2 metal layer serves as the reflection plane of the antenna unit;

The semi-cured sheet, No. 3 core board, the other semi-cured sheet, and the above-mentioned processed RF front-end modules are stacked together from top to bottom for vacuum lamination. After high temperature curing, the prepreg is transformed into No. 4 dielectric layer and No. 3 dielectric layer. , where the No. 2 metal layer in the RF front-end module faces upward;

Process metallized blind holes in the No. 2 core board, process metallized through holes in the whole structure, metallized blind holes are used as signal holes, power holes and electromagnetic shielding grids, and metallized through holes are used as feed holes for antennas ;

The upper surface of the No. 4 dielectric layer is patterned to process the antenna unit;

The lower surface of the No. 2 core board is patterned, then green oil is applied to the upper and lower surfaces of the package body, and surface mount passive components and solder balls are assembled on the bottom of the package body.

(3) Beneficial effects

The packaging method of organic core board embedded and flip-chip bonding is adopted, and the parasitic effect introduced by the use of wire bonding is significantly reduced under the condition that the back of the chip is connected to the metal ground, and the package profile is reduced at the same time.

The reflection plane of the antenna is a periodic metal structure with in-phase reflection properties, which can improve the antenna bandwidth, gain and radiation efficiency in the case of low profile.

The antenna and the RF front-end are placed vertically and interconnected through metallized through holes, which can effectively reduce the electromagnetic interference between the antenna and the RF front-end, and reduce the packaging area.

The sidewalls of the cavity where the active chips are buried are all plated with metal layers, and the combination of the metal hole grid structure can achieve good electromagnetic isolation between the active chips and between the active chips and the antenna.

Surface-mount passive components and single-layer capacitors are also embedded in the same organic core board, enabling high-density integration of the RF front-end.

Description of drawings

FIG. 1 is a structural diagram of an organic substrate embedded package integrating an antenna and a radio frequency front end according to an embodiment of the present invention.

FIG. 2 is a structural diagram of a manufacturing step 1 of the package structure shown in FIG. 1 .

FIG. 3 is a structural diagram of the preparation step 2 of the package structure shown in FIG. 1 .

FIG. 4 is a structural diagram of a manufacturing step 3 of the package structure shown in FIG. 1 .

FIG. 5 is a structural diagram of the preparation step 4 of the package structure shown in FIG. 1 .

FIG. 6 is a structural diagram of the preparation step 5 of the package structure shown in FIG. 1 .

FIG. 7 is another structural diagram of step 5 of the packaging structure shown in FIG. 1 .

FIG. 8 is a structural diagram of the preparation step 6 of the package structure shown in FIG. 1 .

FIG. 9 is a structural diagram of the preparation step 7 of the package structure shown in FIG. 1 .

FIG. 10 is a structural diagram of the preparation step 8 of the package structure shown in FIG. 1 .

[Description of reference numerals]

No. 1 core board, No. 11 metal layer,

2 active chips, 21 chip pads, 22 metal bumps, 23 active chip backside metal,

24 buried surface mount passive components, 25 surface mount passive components, 26 single-layer capacitors,

27 single-layer capacitor electrodes,

3 No. 2 core board, 31 electromagnetic shielding hole grid, 32 metallized blind hole capture pad, 33 component pad 35 metallized blind hole,

4 No. 1 dielectric layer,

5 No. 2 dielectric layer, 51 No. 2 metal layer, 52 metallized blind hole, 53 sidewall dielectric, 54 metallized through hole

6 No. 3 core board, 61 Periodic metal structure,

7 No. 3 dielectric layer,

8 No. 4 dielectric layers, 81 antenna elements,

9 metallized vias,

10 green oil layers,

12 solder balls.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

The present invention discloses an organic substrate embedded packaging structure integrating an antenna and a radio frequency front end. Please refer to FIG. 1 , which includes: an antenna module; The number core board 1 includes at least one through slot inside; at least one active chip 2 has an active surface on one side and an active chip back metal 23 on the other side surface, and the active chip 2 is embedded in the number one In the through groove of the core board 1; the No. 1 dielectric layer 4 is placed under the No. 1 core board 1, and a through groove is provided at the corresponding position of the through groove in the No. 1 core board 1; the No. 2 core board 3 is placed on the No. 1 core board Below the dielectric layer 4, the upper surface is provided with a plurality of component pads 33; wherein, the active surface of the active chip 2 faces down, and is flip-mounted on the upper surface of the second core board 3. The component pads 33 The second dielectric layer 5 is placed above the first core board 1, and the second dielectric layer 5 is provided with a plurality of metallized blind holes 52, which are used as the radio frequency front-end module components to connect to the metal ground plane. The second metal layer 51 channels.

In addition, the sidewall of the through groove of the No. 1 core board 1 is further plated with a No. 1 metal layer 11 , and a dielectric layer is also disposed between the No. 1 metal layer 11 and the active chip 2 . In an embodiment of the present invention, the RF front-end module further includes at least one embedded surface mount passive component 24, and the embedded surface mount passive component 24 has a pad on one side and is embedded in a No. 1 core. In the through slot of the board 1, the side with the pads faces down, and is flipped on the component pads 33 on the upper surface of the second core board 3. The RF front-end module also includes at least one single-layer capacitor 26, so The single-layer capacitor 26 is embedded in the through groove of the No. 1 core board 1 , and flip-chipped on the component pads 33 on the upper surface of the No. 2 core board 3 . In addition, the No. 2 core board 3 is provided with a plurality of metallized blind holes 35, and the active chip 2 can be connected to the external circuit through the plurality of metallized blind holes 35. At the same time, the No. 2 core board 3 is also drilled with The plurality of electromagnetic shielding hole grids 31 together with the No. 1 metal layer 11 constitute a metal shielding cavity for shielding electromagnetic interference between the active chip 2 and other active chips or antenna units 81 . In this embodiment, the No. 1 core board 1 is embedded and combined with the active chip 2 and the embedded surface-mount passive component 24 in a flip-chip packaging method. Under the condition that the active chip 2 is connected to the metal ground at the back, it is significantly Reduces parasitics introduced by using wire bonds while reducing package profile.

In an embodiment of the present invention, the antenna module includes: at least one antenna unit 81; a periodic metal structure 61, which together with the second metal 51 serves as a reflection plane of the antenna unit; in addition, the antenna module also Including: No. 3 core board 6, the periodic metal structure 61 is electroplated on its upper surface; No. 3 dielectric layer 7 and No. 4 dielectric layer 8, respectively arranged between No. 3 core board 6 and No. 2 metal layer 51, and Between the antenna element 81 and the periodic metal structure 61 .

In an embodiment of the present invention, the periodic metal structure 61 is an electromagnetic structure, and has in-phase reflection characteristics in the set millimeter wave band. The antenna unit 81 is placed vertically with the radio frequency front-end module, and the The holes 9 are interconnected to reduce electromagnetic interference between the antenna module and the RF front-end module.

In addition, a plurality of solder balls 12 are arranged on the lower surface of the second core board 3 for connecting to external circuits.

Preferably, the dielectric layer in the encapsulation structure is formed by pressing a prepreg and then curing.

The present invention also discloses the preparation steps of the encapsulation structure. The following will describe the detailed preparation method of the encapsulation structure provided by the present invention step by step with reference to the accompanying drawings. Provides a comprehensive understanding of embodiments of the present invention. Obviously, however, one or more embodiments may be practiced without these specific details. It should be appreciated by those skilled in the art that the following specific details should not be construed as limitations of the invention.

The preparation steps shown include:

Step 1, please refer to FIG. 2, pattern on the top surface of the second core board 3, which includes component pads 33, metallized blind via capture pads 32, interconnect lines and the like.

Step 2, please refer to FIG. 3, place the No. 2 core board 3 on the high-temperature bonding table, process the metal bumps 22 on the component pads 33 by a wire bonding machine, and flatten the metal bumps 22 to an approximate height Consistent.

Step 3, please refer to FIG. 4, place the active surface of the active chip 2 and the surface-mounted passive component 24 with the pads facing down, and flip them on the No. 2 core board 3 by hot pressing. At the same time, the single-layer capacitor 26 is also flip-chipped on the upper surface of the third core board 3 . The back metal 23 of the active chip 2 is the back metal of the active chip 2, and the single-layer capacitor electrode 27 is an electrode of the single-layer capacitor 26. In the embodiment of the present invention, the active chip 2, buried The surface mount passive component 24 and the single-layer capacitor 26 need to have similar thicknesses, which is convenient for packaging.

Step 4, please refer to FIG. 5, use the method of laser milling groove to manufacture the through groove in which the active chip 2 and the surface mount passive component 24 are embedded. In the embodiment of the present invention, the through groove is The area should be slightly larger than that of the embedded device, a No. 1 metal layer 11 is plated on the sidewall of the through groove, and the upper and lower surfaces of the No. 1 core board 1 are patterned by photolithography.

Step 5, please refer to Fig. 6 and Fig. 7, from top to bottom, stack the semi-cured sheet, No. 1 core board 1, the other semi-cured sheet, and No. 2 core board 3, stack them together, perform vacuum pressing, and then cure at high temperature. The prepreg is transformed into No. 1 dielectric layer 4, and the other prepreg is transformed into No. 2 dielectric layer 5; on the prepreg converted into No. 1 dielectric layer 4, the area of the through grooves in the No. 2 core board 1 is slightly cut by laser milling. A large through groove, in which the upper surface of the No. 3 core board 3 is flipped with the active chip 2, and the surface-mount passive components 24 and the single-layer capacitor 26 are buried.

Step 6, please refer to FIG. 8 , make metallized blind holes 52 and metallized through holes 54 in the No. 2 dielectric layer 5, wherein the metallized blind holes 52 include metallized blind holes whose backside metal 23 of the active chip is grounded, a single-layer metallized blind hole Another single-layer capacitor electrode 27 of the capacitor 26 is a metallized blind hole grounded, and a metal hole grid for electromagnetic shielding. The metallized through holes 54 are mainly ground holes, and then the upper surface of the second dielectric layer 5 is patterned to form the second metal layer 51;

Step 7, please refer to FIG. 9, pattern the upper surface of the No. 3 core board 6 by photolithography, and then electroplate the periodic metal structure 61 on the upper surface. In the embodiment of the present invention, the periodic metal structure 61 is Set the in-phase reflection characteristic in the millimeter wave band.

Step 8, please refer to FIG. 10, from top to bottom, stack the semi-cured sheet, the No. 3 core board 6, the other semi-cured sheet and the RF front-end module processed above, and perform vacuum pressing. After high temperature curing, the semi-cured sheet is transformed into No. 3 dielectric layer 7, the other prepreg is transformed into No. 4 dielectric layer 8, wherein the No. 2 metal layer 51 of the RF front-end module faces upward.

Step 9, please refer to FIG. 1 again, process metallized blind holes 35 in the second core board 3, and process metallized through holes 9 in the whole structure. The metallized blind holes 35 are mainly used as signal holes and power holes, as well as electromagnetic holes. The shielding hole grid 31, the electromagnetic shielding hole grid 31 and the No. 1 metal layer 11 form a metal shielding cavity, the metallized through hole 9 is used as the feeding hole of the antenna, the upper surface of the No. 4 dielectric layer 8 is patterned, and the antenna unit 81 is processed. , wherein the antenna unit 81 is placed vertically with the radio frequency front end, and is interconnected through metallized through holes 9 to reduce the electromagnetic interference between the antenna and the radio frequency front end, and then coat the upper and lower surfaces of the green oil layer 10 respectively. The lower surface of the board 3 is patterned, and the surface mount passive components 25 and the solder balls 12 are assembled on the bottom of the package.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above-mentioned specific embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principle of the present invention, any modifications, equivalent replacements, improvements, etc. made should be included within the protection scope of the present invention.

Claims (13)

1. An organic substrate embedded package structure integrating an antenna and a radio frequency front end, comprising:

an antenna module; and

a radio frequency front end module disposed below the antenna module, comprising:

the first core board comprises at least one through groove inside;

at least one active chip, one side surface of which is an active surface and the other side surface of which is back metal, wherein the active chip is embedded in the through groove of the first core board;

the first dielectric layer is arranged below the first core plate, and a through groove is arranged at a position corresponding to the through groove in the first core plate;

the second core board is arranged below the first dielectric layer, and the upper surface of the second core board is provided with a plurality of component bonding pads and an interconnection structure;

the second dielectric layer is arranged above the first core plate, and a plurality of metallized blind holes are arranged in the second dielectric layer in a penetrating manner;

at least one surface-mounted passive element, wherein one side of the surface-mounted passive element is provided with a bonding pad and is embedded in the through groove of the first core plate, one side of the bonding pad faces downwards and is inversely arranged on the bonding pad of the surface element device on the second core plate;

the single-layer capacitor is embedded in the through groove of the first core plate and is inversely arranged on the surface element bonding pad on the second core plate;

and one side of the active surface of the active chip faces downwards and is inversely arranged on the surface element bonding pad on the second core plate.

2. The package structure of claim 1, wherein a sidewall of the through-slot of the core board is further plated with a metal layer, and a dielectric layer is further disposed between the metal layer and the active chip.

3. The package structure of claim 2, wherein a plurality of electromagnetic shielding grids are formed through the second core board, and form a metal shielding cavity with the first metal layer.

4. The package structure of claim 1, wherein the second core board has a plurality of blind metallized vias formed therethrough, and the active chip, the embedded surface-mount passive component and the single-layer capacitor are interconnected to the peripheral circuit through the blind metallized vias in the second core board.

5. The package structure of claim 1, wherein the RF front-end module further comprises a plurality of metallized through holes.

6. The package structure of claim 1, wherein the antenna module comprises:

at least one antenna element;

a layer of periodic metal structure;

and the second metal layer and the periodic metal structure are jointly used as an antenna reflection plane.

7. The package structure of claim 6, wherein the active die back metal is connected to the metal layer II through a metalized blind via of the dielectric layer II.

8. The package structure of claim 6, wherein the other electrode of the single layer capacitor is connected to the metal layer II through a blind via metallization of the dielectric layer II.

9. The package structure of claim 6, wherein the antenna module further comprises

The third core plate, the periodic metal structure is electroplated on the upper surface;

the third dielectric layer is arranged between the third core plate and the second metal layer;

and the fourth dielectric layer is arranged between the antenna unit and the periodic metal structure.

10. The package structure of claim 6, wherein the periodic metal structure is an electromagnetic structure having in-phase reflection characteristics in a given millimeter wave band.

11. The package structure of claim 6, wherein the antenna unit is vertically disposed with respect to the RF front end module and interconnected by a metallized via for reducing electromagnetic interference between the antenna module and the RF front end module.

12. The package structure according to any one of claims 1, 2 and 9, wherein the dielectric layer is formed by laminating and curing prepregs.

13. The package structure of claim 1, wherein a plurality of solder balls are further disposed on a lower surface of the second core board.

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