MCM encapsulation structure and manufacturing method thereof

文档序号：1801166 发布日期：2021-11-05 浏览：13次中文

阅读说明：本技术 Mcm封装结构及其制作方法 (MCM encapsulation structure and manufacturing method thereof ) 是由杨威源于 2021-07-29 设计创作，主要内容包括：本发明提供了一种MCM封装结构及其制作方法,MCM封装结构中,第一裸片、第二裸片以及电连接结构封装在塑封层内,第一裸片设有容纳槽,容纳槽的开口位于第一裸片的背面；第二裸片设置于容纳槽内,且通过导热胶与第一裸片固定,第二裸片的活性面与第一裸片的活性面朝向相背；塑封层的正面一侧设有散热电极,散热电极与导热胶连接。根据本发明的实施例,由于导热胶不但可与容纳槽的底壁与四个侧壁接触,而且还可与第二裸片的底壁与四个侧壁接触,接触面积较大,因而对第一裸片与第二裸片的散热效果都得以提升。(The invention provides an MCM (chip on chip) packaging structure and a manufacturing method thereof, wherein in the MCM packaging structure, a first bare chip, a second bare chip and an electric connection structure are packaged in a plastic package layer, the first bare chip is provided with a containing groove, and an opening of the containing groove is positioned on the back surface of the first bare chip; the second bare chip is arranged in the accommodating groove and fixed with the first bare chip through the heat-conducting glue, and the active surface of the second bare chip is opposite to the active surface of the first bare chip; and a heat dissipation electrode is arranged on one side of the front surface of the plastic packaging layer and is connected with the heat conduction glue. According to the embodiment of the invention, the heat conducting glue can be contacted with the bottom wall and the four side walls of the accommodating groove and can also be contacted with the bottom wall and the four side walls of the second bare chip, so that the contact area is larger, and the heat dissipation effect on the first bare chip and the second bare chip is improved.)

1. An MCM package structure, comprising:

a first die comprising a number of first bonding pads, the first bonding pads located on an active side of the first die; the first bare chip is provided with a containing groove, and an opening of the containing groove is positioned on the back surface of the first bare chip;

a second die comprising a number of second bonding pads, the second bonding pads located on an active side of the second die; the second bare chip is arranged in the accommodating groove and fixed with the first bare chip through a heat-conducting glue, and the active surface of the second bare chip is opposite to the active surface of the first bare chip;

a plastic packaging layer at least covering the side surface of the first bare chip; the molding compound layer comprises a front surface and a back surface which are opposite, the front surface of the molding compound layer is in the same orientation with the active surface of the second die, and the back surface of the molding compound layer is in the same orientation with the active surface of the first die;

the electric connection structure penetrates between the front surface of the plastic packaging layer and the back surface of the plastic packaging layer;

the first conductive structure is positioned on one side of the back surface of the plastic packaging layer; the first conductive structure at least connects the electrical connection structure with at least one of the first pads;

the second conductive structure is positioned on one side of the front surface of the plastic packaging layer; the second conductive structure at least connects the electrical connection structure with at least one of the second pads;

the heat dissipation electrode is positioned on one side of the front surface of the plastic packaging layer; the heat dissipation electrode is connected with the heat conduction glue.

2. The MCM package structure of claim 1, wherein the thermal paste fills between the receiving groove and the second die, and the thermal paste contacts at least a partial area of a side wall of the receiving groove, at least a partial area of a side wall of the second die, a bottom wall of the receiving groove, and a bottom wall of the second die.

3. The MCM package structure of claim 1, wherein the electrical connection structure is a conductive post, a conductive plug, or a conductive layer located on an inner wall of a via.

4. The MCM package structure of claim 1, wherein the first die includes a first back electrode located at a back side of the first die; and/or the second die comprises a second back electrode, the second back electrode being located on the back side of the second die; the heat-conducting glue has a conductive function, and the heat-radiating electrode is used for electrically connecting a fixed potential.

5. The MCM package structure of claim 1, wherein the receiving groove is stepped.

6. The MCM package structure of claim 1, wherein the active side of the first die is covered with a first protective layer having a first opening exposing the first pad; and/or the active side of the second die is covered with a second protective layer having a second opening exposing the second pad.

7. The MCM package structure of claim 1, wherein an active side of the second die, the thermal conductive paste, and a back side of the first die are covered with a leveling layer, an upper surface of the leveling layer being flush with a front side of the molding layer.

8. A method for manufacturing an MCM package structure is characterized by comprising the following steps:

forming a plastic intermediate, the plastic intermediate comprising:

and a molding compound layer at least covering the side surface of the first bare chip; the molding compound layer comprises a front surface and a back surface which are opposite, the front surface of the molding compound layer is in the same orientation with the active surface of the second die, and the back surface of the molding compound layer is in the same orientation with the active surface of the first die;

forming one of a first conductive structure and a second conductive structure on the plastic package intermediate, wherein the first conductive structure is positioned on one side of the back surface of the plastic package layer and is connected with the first bonding pad; the second conductive structure is positioned on one side of the front surface of the plastic packaging layer and is connected with the second bonding pad; forming a heat dissipation electrode while forming the second conductive structure, wherein the heat dissipation electrode is connected with the heat conduction glue;

forming a through hole in the plastic packaging layer, wherein the bottom wall of the through hole exposes the formed first conductive structure or the second conductive structure;

and forming the other one of the first conductive structure and the second conductive structure on the plastic package intermediate, simultaneously forming a conductive layer on the side wall and the bottom wall of the through hole and the plastic package layer outside the through hole, and connecting the other one of the first conductive structure and the second conductive structure with the conductive layer on the plastic package layer.

9. The method for manufacturing an MCM package structure according to claim 8, wherein the method for forming the plastic package intermediate includes:

providing a carrier plate and bearing in at least one group of to-be-molded parts of the carrier plate, each group of to-be-molded parts comprises: a first die and a second die; the first die comprises a plurality of first bonding pads, and the first bonding pads are positioned on the active surface of the first die; the first bare chip is provided with a containing groove, and an opening of the containing groove is positioned on the back surface of the first bare chip; the second die comprises a plurality of second bonding pads, and the second bonding pads are positioned on the active surface of the second die; the second bare chip is arranged in the accommodating groove and fixed with the first bare chip through a heat-conducting glue, and the active surface of the second bare chip is opposite to the active surface of the first bare chip; an active side of the first die faces the carrier plate;

forming a plastic packaging layer for embedding the piece to be plastic packaged on the surface of the carrier plate, wherein the plastic packaging layer comprises a front surface and a back surface which are opposite; thinning the plastic packaging layer from the front surface of the plastic packaging layer until the active surface of the second bare chip is exposed; and removing the carrier plate.

10. The method for manufacturing an MCM package structure according to claim 8, wherein the method for forming the plastic package intermediate includes:

providing a carrier plate and bearing in at least one group of to-be-molded parts of the carrier plate, each group of to-be-molded parts comprises: a first die, a second die, and a leveling layer; the first die comprises a plurality of first bonding pads, and the first bonding pads are positioned on the active surface of the first die; the first bare chip is provided with a containing groove, and an opening of the containing groove is positioned on the back surface of the first bare chip; the second die comprises a plurality of second bonding pads, and the second bonding pads are positioned on the active surface of the second die; the second bare chip is arranged in the accommodating groove and fixed with the first bare chip through a heat-conducting glue, and the active surface of the second bare chip is opposite to the active surface of the first bare chip; the leveling layer covers the active surface of the second bare chip, the heat conducting glue and the back surface of the first bare chip; the leveling layer faces the carrier plate;

forming a plastic packaging layer for embedding the piece to be molded on the surface of the carrier plate, wherein the plastic packaging layer comprises a front surface and a back surface which are opposite, and the front surface of the plastic packaging layer and the leveling layer are in the same direction; thinning the plastic packaging layer from the back surface of the plastic packaging layer until the active surface of the first bare chip is exposed; and removing the carrier plate.

11. A method for fabricating an MCM package structure according to claim 9 or 10, wherein the method for forming each group of the members to be molded includes:

providing a first bare chip, and arranging liquid or semi-solid heat-conducting glue in the accommodating groove;

providing a second die, an active surface of the second die facing away from an active surface of the first die, the second die being disposed within the receiving cavity; the liquid or semi-solid heat conduction glue is filled between the accommodating groove and the second bare chip, and the liquid or semi-solid heat conduction glue is contacted with at least partial area of the side wall of the accommodating groove, at least partial area of the side wall of the second bare chip, the bottom wall of the accommodating groove and the bottom wall of the second bare chip;

and solidifying the liquid or semi-solid heat-conducting glue to fix the second bare chip and the first bare chip.

12. A method for manufacturing an MCM package structure is characterized by comprising the following steps:

forming a plastic intermediate, the plastic intermediate comprising:

forming a conductive plug in the plastic packaging layer, wherein the conductive plug comprises a first end and a second end which are opposite, and the first end is connected with the formed first conductive structure or the second conductive structure;

and forming the other of the first conductive structure and the second conductive structure on the plastic package intermediate body and the second end of the conductive plug.

13. A method for manufacturing an MCM package structure is characterized by comprising the following steps:

providing a carrier plate and bearing in at least one group of to-be-molded parts of the carrier plate, each group of to-be-molded parts comprises: a first die, a second die, and a conductive pillar; the first die comprises a plurality of first bonding pads, and the first bonding pads are positioned on the active surface of the first die; the first bare chip is provided with a containing groove, and an opening of the containing groove is positioned on the back surface of the first bare chip; the second die comprises a plurality of second bonding pads, and the second bonding pads are positioned on the active surface of the second die; the second bare chip is arranged in the accommodating groove and fixed with the first bare chip through a heat-conducting glue, and the active surface of the second bare chip is opposite to the active surface of the first bare chip; the conductive post comprises a first end and a second end which are opposite; the active surface of the first die and the first end of the conductive pillar face the carrier plate;

forming a plastic intermediate, the plastic intermediate comprising:

a conductive post including opposing first and second ends;

and a molding compound layer at least covering the side surface of the first bare chip and the conductive column; the molding compound layer comprises a front surface and a back surface which are opposite, the front surface of the molding compound layer, the active surface of the second die and the first ends of the conductive posts are in the same orientation, and the back surface of the molding compound layer, the active surface of the first die and the second ends of the conductive posts are in the same orientation;

forming one of a first conductive structure and a second conductive structure on the plastic package intermediate, wherein the first conductive structure is located on one side of the back surface of the plastic package layer and at least connected with the conductive column and at least one first bonding pad; the second conductive structure is positioned on one side of the front surface of the plastic packaging layer and at least connects the conductive column with at least one second bonding pad; forming a heat dissipation electrode while forming the second conductive structure, wherein the heat dissipation electrode is connected with the heat conduction glue;

forming the other of the first conductive structure and the second conductive structure on the plastic package intermediate;

and cutting to form the MCM package structure.

Technical Field

The invention relates to the technical field of chip packaging, in particular to an MCM (Multi-chip Module) packaging structure and a manufacturing method thereof.

Background

In the packaging process, dies with different functions are often packaged in a packaging structure to form a specific function, which is called a Multi-Chip Module (MCM), and has the advantages of small size, high reliability, high performance, and multiple functions.

In recent years, with the continuous development of circuit integration technology, electronic products are increasingly developed toward miniaturization, intellectualization, high integration, high performance and high reliability. The packaging technique not only affects the performance of the product, but also restricts the miniaturization of the product.

After the product is miniaturized, the heat dissipation performance is important for the product.

In view of this, the present invention provides an MCM package structure and a method for manufacturing the same, so as to meet the requirements of the package structure for small size, compact structure, high integration level, and good heat dissipation performance.

Disclosure of Invention

The invention aims to provide an MCM (Multi-chip Module) packaging structure and a manufacturing method thereof, so as to meet the requirements of small size, compact structure, high integration level and good heat dissipation performance of the packaging structure.

To achieve the above object, a first aspect of the present invention provides an MCM package structure, including:

the electric connection structure penetrates between the front surface of the plastic packaging layer and the back surface of the plastic packaging layer;

the heat dissipation electrode is positioned on one side of the front surface of the plastic packaging layer; the heat dissipation electrode is connected with the heat conduction glue.

Optionally, the thermal conductive paste is filled between the receiving groove and the second die, and the thermal conductive paste contacts at least a partial region of a side wall of the receiving groove, at least a partial region of a side wall of the second die, a bottom wall of the receiving groove, and a bottom wall of the second die.

Optionally, the electrical connection structure is a conductive pillar, a conductive plug, or a conductive layer located on an inner wall of the via hole.

Optionally, the first die comprises a first back electrode, the first back electrode being located on a back side of the first die; and/or the second die comprises a second back electrode, the second back electrode being located on the back side of the second die; the heat-conducting glue has a conductive function, and the heat-radiating electrode is used for electrically connecting a fixed potential.

Optionally, the thermally conductive paste includes: nano copper/conductive polymer composite material.

Optionally, the first conductive structure is a first redistribution layer, or the first conductive structure is a first conductive bump, or the first conductive structure includes a first redistribution layer and a first conductive bump on the first redistribution layer; and/or the second conductive structure is a second conductive bump, or the second conductive structure includes a second re-wiring layer and a second conductive bump on the second re-wiring layer.

Optionally, the receiving groove is stepped.

Optionally, the active side of the first die is covered with a first protective layer having a first opening exposing the first pad; and/or the active side of the second die is covered with a second protective layer having a second opening exposing the second pad.

Optionally, the active surface of the second die, the thermal conductive paste, and the back surface of the first die are covered with a leveling layer, and an upper surface of the leveling layer is flush with the front surface of the molding compound layer.

A second aspect of the present invention provides a method for manufacturing an MCM package structure, including:

forming a plastic intermediate, the plastic intermediate comprising:

forming a through hole in the plastic packaging layer, wherein the bottom wall of the through hole exposes the formed first conductive structure or the second conductive structure;

Optionally, the method for forming the plastic package intermediate includes:

Optionally, the method for forming each group of the to-be-molded parts includes:

providing a first bare chip, and arranging liquid or semi-solid heat-conducting glue in the accommodating groove;

providing a second die, an active surface of the second die facing away from an active surface of the first die, the second die being disposed within the receiving cavity;

and solidifying the liquid or semi-solid heat-conducting glue to fix the second bare chip and the first bare chip.

Optionally, after the step of disposing the second die in the receiving groove and before the step of curing the liquid or semi-solid thermal conductive adhesive, the liquid or semi-solid thermal conductive adhesive is filled between the receiving groove and the second die, and the liquid or semi-solid thermal conductive adhesive contacts at least a partial region of a side wall of the receiving groove, at least a partial region of a side wall of the second die, a bottom wall of the receiving groove, and a bottom wall of the second die.

A third aspect of the present invention provides another method for fabricating an MCM package structure, including:

forming a plastic intermediate, the plastic intermediate comprising:

and forming the other of the first conductive structure and the second conductive structure on the plastic package intermediate body and the second end of the conductive plug.

A fourth aspect of the present invention provides a method for manufacturing an MCM package structure, including:

forming a plastic intermediate, the plastic intermediate comprising:

a conductive post including opposing first and second ends;

forming the other of the first conductive structure and the second conductive structure on the plastic package intermediate;

and cutting to form the MCM package structure.

The inventor finds out in the development process that: the MCM package structure can be implemented by two methods: a plurality of die stacks within the package structure and a plurality of chip package structure stacks within the package structure.

A plurality of bare chips in the packaging structure are stacked, each bare chip is firstly arranged on a corresponding substrate in an inverted mode, the two sides of each substrate are provided with interconnection welding points, and the plurality of substrates can be stacked through the interconnection welding points to be electrically interconnected.

The stacking of the chip packaging structures in the packaging structure is to overlap small-scale packaging bodies of the same type and similar sizes, and to solder the same terminals of the overlapped small-scale packaging bodies together by utilizing the terminal arrangement of the original standard packaging bodies so as to realize the electric connection among the packaging bodies.

However, on the one hand, the MCM package structure described above is large in size and cumbersome in packaging process. On the other hand, the heat dissipation of the package structure is realized through the heat dissipation electrode electrically connected with the bonding pad, and the heat dissipation effect is limited.

Different from the two packaging modes, in the MCM packaging structure, the first bare chip and the second bare chip are packaged in the plastic package layer, the first bare chip comprises a plurality of first bonding pads, the first bonding pads are positioned on the active surface of the first bare chip, the first bare chip is provided with a containing groove, and the opening of the containing groove is positioned on the back surface of the first bare chip; the second die comprises a plurality of second bonding pads, and the second bonding pads are positioned on the active surface of the second die; the second bare chip is arranged in the accommodating groove and fixed with the first bare chip through the heat-conducting glue, and the active surface of the second bare chip is opposite to the active surface of the first bare chip; the electric connection structure penetrates between the front surface of the plastic packaging layer and the back surface of the plastic packaging layer; one side of the back surface of the plastic packaging layer is provided with a first conductive structure, and the first conductive structure is at least connected with the electric connection structure and at least one first bonding pad; and a second conductive structure and a heat dissipation electrode are arranged on one side of the front surface of the plastic packaging layer, the second conductive structure is at least connected with the electric connection structure and at least one second bonding pad, and the heat dissipation electrode is connected with the heat conduction glue. The MCM package structure enables the heat-conducting glue to be in contact with the bottom wall and the four side walls of the accommodating groove and the bottom wall and the four side walls of the second bare chip, and the contact area is large, so that the heat dissipation effect of the first bare chip and the second bare chip is improved.

Drawings

Fig. 1 is a schematic cross-sectional structure diagram of an MCM package structure of a first embodiment of the invention;

FIG. 2 is a flow chart of a method of fabricating the MCM package structure of FIG. 1;

FIGS. 3-11 are intermediate schematic diagrams corresponding to the flow chart of FIG. 2;

fig. 12 is a schematic cross-sectional structure diagram of an MCM package structure of the second embodiment of the invention;

FIG. 13 is a flow chart of a method of fabricating the MCM package structure of FIG. 12;

fig. 14 is a schematic cross-sectional structure view of an MCM package structure of a third embodiment of the invention;

FIG. 15 is a flow chart of a method of fabricating the MCM package structure of FIG. 14;

fig. 16 is a schematic cross-sectional structure view of an MCM package structure of a fourth embodiment of the invention;

fig. 17 is a schematic cross-sectional structure diagram of an MCM package structure of a fifth embodiment of the invention.

To facilitate an understanding of the invention, all reference numerals appearing in the invention are listed below:

MCM package structures 1, 2, 3, 4, 5 first die 11

First pads 111 the back side 11b of the first die

Active surface 11a of the first die the second die 12

Second pads 121 the back side 12b of the second die

Active side 12a of second die receiving pocket 110

Heat-conducting glue 13 plastic packaging layer 14

Front side of the plastic layer 14a and back side of the plastic layer 14b

First conductive bump 15 via hole 16

Conductive layer 17 second conductive bump 18

Leveling layer 20 of heat dissipation electrode 19

First protective layer 112 second protective layer 122

Leveling layer 20 plastic-sealed intermediate 10

Carrier plate 30 to-be-molded part 40

Conductive plug 21 first end 21a of conductive plug

Conductive plug second end 21b conductive post 22

First end 22a of the conductive post and second end 22b of the conductive post

First back electrode 113 and second back electrode 123

First recess 110a and second recess 110b

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

Fig. 1 is a schematic cross-sectional structure diagram of an MCM package structure of a first embodiment of the invention.

Referring to fig. 1, MCM package structure 1 includes:

a first die 11 including a plurality of first bonding pads 111, the first bonding pads 111 being located on an active surface 11a of the first die 11; the first die 11 is provided with a receiving groove 110, and an opening of the receiving groove 110 is located on the back surface 11b of the first die 11;

a second die 12 including a plurality of second bonding pads 121, the second bonding pads 121 being located on an active surface 12a of the second die 12; the second die 12 is disposed in the accommodating groove 110 and fixed to the first die 11 by the thermal conductive adhesive 13, and an active surface 12a of the second die 12 faces away from an active surface 11a of the first die 11;

a molding compound layer 14 at least covering the side surface of the first die 11; the molding compound layer 14 comprises a front surface 14a and a back surface 14b which are opposite, the front surface 14a of the molding compound layer 14 is in the same orientation with the active surface 12a of the second die 12, and the back surface 14b of the molding compound layer 14 is in the same orientation with the active surface 11a of the first die 11;

a first conductive bump 15 located on the back side 14b of the plastic package layer; the first conductive bump 15 is connected to the first pad 111;

a via hole 16 penetrating between the front surface 14a of the molding layer 14 and the back surface 14b of the molding layer 14, the via hole 16 exposing the first conductive bump 15;

the conductive layer 17 covers the inner wall of the via hole 16 and the front surface 14a of the plastic packaging layer 14 outside the via hole 16;

a second conductive bump 18 located on the front side 14a of the plastic package layer; the second conductive bump 18 is connected to the second pad 121, and the second conductive bump 18 is connected to the conductive layer 17;

the heat dissipation electrode 19 is positioned on one side of the front surface 14a of the plastic packaging layer; the heat dissipation electrode 19 is connected to the heat conductive paste 13.

The first DIE 11 and the second DIE 12 may be a POWER DIE (POWER DIE), a MEMORY DIE (MEMORY DIE), a sensing DIE (SENSOR DIE), or a RADIO frequency DIE (RADIO frequency DIE), or corresponding control chips. The present embodiment does not limit the functions of the first die 11 and the second die 12.

The first die 11 includes an active surface 11a and a back surface 11b opposite to each other. The first pad 111 is located on the active surface 11 a. The first die 11 may include a variety of devices formed on a semiconductor substrate, and electrical interconnect structures electrically connected to the various devices. The first pads 111 are connected to the electrical interconnection structure for inputting/outputting electrical signals of the respective devices.

The second die 12 includes opposing active and backside surfaces 12a and 12 b. The second pad 121 is located on the active surface 12 a. The second die 12 may include a variety of devices formed on a semiconductor substrate, as well as electrical interconnect structures electrically connected to the various devices. The second pads 121 are connected to the electrical interconnection structure for inputting/outputting electrical signals of the respective devices.

The second die 12 is disposed in the receiving groove 110 of the first die 11, and the MCM package 1 may be reduced in size compared to a back-to-back arrangement, a diagonal arrangement, or a side-by-side arrangement. The back-to-back arrangement mode is as follows: the back surface 11b of the first die 11 is bonded to the back surface 12b of the second die 12. The oblique arrangement mode is as follows: the back surface 11b of the first die 11 faces the back surface 12b of the second die 12, but is displaced in both the thickness direction and the vertical thickness direction of the first die 11 and the second die 12. The parallel arrangement mode is as follows: the back surface 11b of the first die 11 and the back surface 12b of the second die 12 are oriented in the same direction, and the active surface 11a of the first die 11 and the active surface 12a of the second die 12 are oriented in the same direction.

In this embodiment, referring to fig. 1, the active surface 11a of the first die 11 is covered with a first protective layer 112. The active side 12a of the second die 12 is covered with a second protective layer 122. The first protective layer 112 and the second protective layer 122 are made of insulating materials, specifically, may be made of insulating resin materials, and may also be made of inorganic materials. The insulating resin material is, for example, polyimide, epoxy resin, abf (ajinomoto build file), pbo (polybenzoxazole), an organic polymer film, an organic polymer composite material, or other organic materials having similar insulating properties. The inorganic material is, for example, at least one of silicon dioxide and silicon nitride.

The first protective layer 112 has a first opening exposing the first pad 111. The second protective layer 122 has a second opening exposing the second pad 121.

In other embodiments, the first protective layer 112 and/or the second protective layer 122 may be omitted, or when the second protective layer 122 is an inorganic material, the second protective layer 122 has an ABF film thereon.

In one alternative, the thermally conductive paste 13 may include copper powder and a binder. In other alternatives, the thermally conductive paste 13 may also include a thermally conductive polymer material and a binder.

The upper surface of the thermal conductive paste 13 is lower than the upper surface of the second protective layer 122.

In this embodiment, referring to fig. 1, the second protective layer 122, the second pad 121, the thermal conductive adhesive 13, and the back surface 11b of the first die 11 are covered with the leveling layer 20. The material of the leveling layer 20 may be an ABF film.

In other embodiments, the leveling layer 20 may be omitted.

The molding layer 14 includes a front surface 14a and a back surface 14b opposite to each other. In this embodiment, the front surface 14a of the molding layer 14 exposes the leveling layer 20, and the back surface 14b of the molding layer 14 exposes the second protection layer 122.

In this embodiment, the first conductive bump 15 is a back-side-to-outside connection end of the MCM package structure 1, and the second conductive bump 18 is a front-side-to-outside connection end of the MCM package structure 1. The conductive layer 17 enables electrical connection of the first die 11 to the second die 12.

The heat dissipation electrode 19 is connected to the heat conductive paste 13. Since the thermal conductive adhesive 13 is not only in contact with the bottom wall and the four side walls of the accommodating groove 110, but also in contact with the bottom wall and the four side walls of the second bare chip 12, the contact area is large, and thus the heat dissipation effect on the first bare chip 11 and the second bare chip 12 can be improved.

In another embodiment, the first conductive bump 15 may be replaced with a first redistribution layer. The first rewiring layer includes a plurality of metal blocks having one or more layers. A part of the number of metal blocks is selectively electrically connected with a plurality of first bonding pads 111 to realize the circuit layout of the first bonding pads 111; a partial number of metal blocks are electrically connected to the conductive layer 17 to enable the electrical signal of the first die 11 to be directed to the back side 14b of the molding layer 14. The first rewiring layer can improve the wiring complexity of the MCM package structure 1 and improve the integration.

The leveling layer 20 and the front surface 14a of the molding layer 14 may be provided with a first dielectric layer embedding the first redistribution layer. In other words, MCM package 1 has only back-to-out connections.

In some embodiments, the first redistribution layer may be disposed with the first conductive bump 15 and the first dielectric layer, and the first conductive bump 15 is exposed outside the first dielectric layer and still serves as a back-side external connection terminal.

In another embodiment, the second conductive bump 18 may be replaced with a second redistribution layer. The second rewiring layer includes metal blocks having one or more layers. A part of the number of metal blocks is selectively electrically connected with a number of second pads 121 to realize the circuit layout of the second pads 121; a partial number of metal blocks are electrically connected to the conductive layer 17 to effect routing of the electrical signal of the second die 12 to the front side 14a of the molding layer 14. The second rewiring layer can improve the wiring complexity of the MCM package structure 1 and improve the integration.

A second dielectric layer embedding the second redistribution layer may be disposed on the back surface 14b of the molding layer 14. In other words, MCM package 1 has only front-to-exterior connection ends.

In some embodiments, a second conductive bump 18 and a second dielectric layer may be disposed on the second redistribution layer, and the second conductive bump 18 is exposed outside the second dielectric layer and still serves as a front-side external connection terminal.

The material of the first dielectric layer and the second dielectric layer may be an insulating resin material or an inorganic material. The insulating resin material is, for example, polyimide, epoxy resin, abf (ajinomoto build file), pbo (polybenzoxazole), an organic polymer film, an organic polymer composite material, or other organic materials having similar insulating properties. The inorganic material is, for example, at least one of silicon dioxide and silicon nitride. The insulating resin material has a smaller tensile stress than the inorganic material, and can prevent the surface of the MCM package structure 1 from warping.

An embodiment of the present invention provides a method for fabricating the MCM package structure 1 in fig. 1. Fig. 2 is a flow chart of a method of fabrication. Fig. 3 to 11 are intermediate schematic diagrams corresponding to the flow chart in fig. 2.

First, referring to step S1 in fig. 2 and fig. 3, a mold intermediate 10 is formed, and the mold intermediate 10 includes:

and a molding compound layer 14 at least covering the side surface of the first die 11; the molding compound layer 14 includes a front surface 14a and a back surface 14b opposite to each other, the front surface 14a of the molding compound layer 14 is oriented in the same direction as the active surface 12a of the second die 12, and the back surface 14b of the molding compound layer 14 is oriented in the same direction as the active surface 11a of the first die 11.

In this embodiment, forming the plastic intermediate 10 may include steps S11 to S12.

Step S11: referring to fig. 4 and 5, a carrier 30 and a plurality of sets of to-be-molded components 40 carried on the carrier 30 are provided, where each set of to-be-molded components 40 includes: a first die 11 and a second die 12, the first die 11 including a plurality of first bonding pads 111, the first bonding pads 111 being located on an active surface 11a of the first die 11; the first die 11 is provided with a receiving groove 110, and an opening of the receiving groove 110 is located on the back surface 11b of the first die 11; the second die 12 includes a plurality of second bonding pads 121, the second bonding pads 121 are located on the active surface 12a of the second die 12; the second die 12 is disposed in the accommodating groove 110 and fixed to the first die 11 by the thermal conductive adhesive 13, and an active surface 12a of the second die 12 faces away from an active surface 11a of the first die 11; wherein the active surface 11a of the first die 11 faces the carrier 30. Fig. 4 is a top view of a carrier and a plurality of groups of packages to be packaged; fig. 5 is a sectional view taken along the AA line in fig. 4.

The accommodating groove 110 may be implemented by dry etching or wet etching. During the dry etching or the wet etching, the back surface 11b of the first die 11 is covered with a mask layer, and the mask layer used for exposure of the mask layer can be aligned by using the first bonding pad 111 located on the active surface 11a of the first die 11. The location of the first pads 111 may be obtained, for example, using an infrared through first die 11 technique.

In this embodiment, referring to fig. 5, the active surface 11a of the first die 11 is covered with a first protective layer 112. The active side 12a of the second die 12 is covered with a second protective layer 122. The first protective layer 112 and the second protective layer 122 are made of insulating materials, specifically, may be made of insulating resin materials, and may also be made of inorganic materials. The insulating resin material is, for example, polyimide, epoxy resin, abf (ajinomoto build file), pbo (polybenzoxazole), an organic polymer film, an organic polymer composite material, or other organic materials having similar insulating properties. The inorganic material is, for example, at least one of silicon dioxide and silicon nitride.

The first protective layer 112 has a first opening exposing the first pad 111. The second protective layer 122 has a second opening exposing the second pad 121.

In other embodiments, the first protective layer 112 and/or the second protective layer 122 may be omitted.

In this embodiment, the method for forming the group of to-be-molded parts 40 in step S11 may include steps S111 to S114.

Step S111: the first die 11 is provided, and a semi-solid thermal conductive paste is disposed in the accommodating groove 110.

The semi-solid thermally conductive paste may include copper powder and a binder, and may also include a thermally conductive polymer material and a binder. The semi-solid thermally conductive paste may be brushed into the receiving groove 110 using a brush head.

Step S112: a second die 12 is provided, an active surface 12a of the second die 12 faces away from the active surface 11a of the first die 11, and the second die 12 is disposed in the accommodating groove 110.

The second die 12 is embedded in the semi-solid thermal conductive paste when disposed in the receiving cavity 110.

Step S113: and curing the semi-solid heat-conducting glue to fix the second bare chip 12 and the first bare chip 11.

The solidified semi-solid heat-conducting glue can volatilize organic matters in the adhesive by a heating method, so that the adhesive is dense and hard.

In this embodiment, after step S112 and before step S113: the semi-solid thermal conductive paste is filled between the receiving groove 110 and the second die 12, and the semi-solid thermal conductive paste contacts at least a partial region of the side wall of the receiving groove 110, at least a partial region of the side wall of the second die 12, the bottom wall of the receiving groove 110, and the bottom wall of the second die 12.

Step S114: the second protective layer 122, the second pad 121, the thermal conductive paste 13, and the back surface 11b of the first die 11 cover the leveling layer 20. The material of the leveling layer 20 may be an ABF film.

In another embodiment, the method for forming the set of to-be-molded parts 40 of step S11 may include steps S111' to S114.

Step S111': providing the first bare chip 11, disposing a liquid thermal conductive adhesive in the accommodating groove 110, and semi-curing the liquid thermal conductive adhesive to form a semi-solid thermal conductive adhesive.

The liquid heat-conducting glue may include: liquid gold conductive paste and/or liquid carbon conductive paste. The semi-solidification of the liquid heat-conducting glue can be realized by a heating method.

The second die 12 is embedded in the semi-solid thermal conductive paste when disposed in the receiving cavity 110.

Step S113: and curing the semi-solid heat-conducting glue to fix the second bare chip 12 and the first bare chip 11.

The solidified semi-solid heat-conducting glue can volatilize organic matters in the semi-solidified gold heat-conducting glue and/or the semi-solidified carbon heat-conducting glue through a heating method, so that the semi-solidified gold heat-conducting glue is dense and hard.

The carrier plate 30 is a rigid plate and may include a plastic plate, a glass plate, a ceramic plate, a metal plate, or the like.

When the plurality of sets of to-be-molded parts 40 are disposed on the surface of the carrier plate 30, a whole bonding layer may be coated on the surface of the carrier plate 30, and the plurality of sets of to-be-molded parts 40 are disposed on the bonding layer.

The adhesive layer may be made of a material that is easily peeled off so as to peel off the carrier sheet 30, and for example, a thermal release material that can be made to lose adhesiveness by heating or a UV release material that can be made to lose adhesiveness by ultraviolet irradiation may be used.

A group of parts to be molded 40 is located on an area of the surface of the carrier plate 30 for facilitating subsequent cutting. A plurality of sets of to-be-molded parts 40 are fixed on the surface of the carrier plate 30 to simultaneously manufacture a plurality of MCM package structures 1, which is beneficial to batch production and cost reduction. In some embodiments, a set of members to be molded 40 can be fixed on the surface of the carrier 30.

Step S12: referring to fig. 6, a molding layer 14 embedding each group of pieces to be molded 40 is formed on the surface of the carrier plate 30; referring to fig. 7, the molding layer 14 is thinned from the back surface 14b of the molding layer 14 until the active surface 11a of the first die 11 is exposed.

The material of the molding layer 14 may be epoxy resin, polyimide resin, benzocyclobutene resin, polybenzoxazole resin, polybutylene terephthalate, polycarbonate, polyethylene terephthalate, polyethylene, polypropylene, polyolefin, polyurethane, polyolefin, polyethersulfone, polyamide, polyurethane, ethylene-vinyl acetate copolymer, polyvinyl alcohol, or the like. The material of the molding layer 14 may also be various polymers or a composite of resin and polymer. Correspondingly, the plastic package can include filling the liquid plastic package material and then performing high-temperature curing through a plastic package mold. In some embodiments, the molding layer 14 may also be formed by plastic material molding such as hot press molding and transfer molding.

The molding layer 14 may include a front surface 14a and a back surface 14b opposite to each other.

Referring to fig. 7, the plastic encapsulant layer 14 may be thinned using mechanical grinding, such as grinding using a grinding wheel.

In this embodiment, since the active surface 11a of the first die 11 has the first protection layer 112, the molding layer 14 is thinned from the back surface 14b of the molding layer 14 until the first protection layer 112 is exposed.

During the process of forming the molding compound layer 14 and grinding the molding compound layer 14, the first protective layer 112 and the second protective layer 122 can prevent the first bonding pad 111, the first die 11, the second bonding pad 121, and the electrical interconnection structure and devices in the second die 12 from being damaged.

In other embodiments, when the mold intermediate 10 is formed, the active surface 12a of the second die 12 faces the carrier 30 in each group of the to-be-molded components 40. Thereafter, the molding layer 14 is thinned from the front surface 14a of the molding layer 14 until the active surface 11a of the second die 12 is exposed. When the active surface 12a of the second die 12 has the second protective layer 122, the molding layer 14 is thinned from the front surface 14a of the molding layer 14 until the second protective layer 122 is exposed.

Next, referring to step S2 in fig. 2 and fig. 8, a first conductive bump 15 is formed on the molding intermediate 10, and the first conductive bump 15 is located on the molding layer back surface 14b side and connected to the first pad 111.

The first conductive bump 15 may be completed using an electroplating process. The process of electroplating copper or aluminum is mature.

In this embodiment, the first conductive bump 15 is a back-to-outside connection end of the MCM package structure 1.

In other embodiments, an oxidation resistant layer may also be formed on the first conductive bump 15.

The oxidation resistant layer may include: a1) a tin layer, or a2) a nickel layer and a gold layer stacked from bottom to top, or a3) a nickel layer, a palladium layer and a gold layer stacked from bottom to top. The oxidation resistant layer may be formed using an electroplating process. The material of the first conductive bump 15 may be copper, and the anti-oxidation layer can prevent oxidation of copper, thereby preventing deterioration of electrical connection performance due to oxidation of copper.

The leveling layer 20 and the front surface 14a of the molding layer 14 may be provided with a first dielectric layer embedding the first redistribution layer. In other words, the MCM package structure has only back-to-out connections.

In some embodiments, the first redistribution layer may have a first conductive bump 15 disposed thereon, and the first conductive bump 15 is exposed outside the first dielectric layer and still serves as a back-side external connection terminal.

After the first conductive bump 15 is formed, the carrier 30 may be removed. The removing method of the carrier 30 may be laser lift-off, UV irradiation, or other conventional removing methods.

Next, referring to step S3 in fig. 2 and fig. 9, a via hole 16 is formed in the molding layer 14, and a bottom wall of the via hole 16 exposes the formed first conductive bump 15.

The via 16 may be formed using a laser drilling method.

Referring to fig. 9, after removing the carrier plate 30, a support plate 31 may be disposed on the first conductive bump 15.

The support plate 31 is a hard plate member and may include a glass plate, a ceramic plate, a metal plate, and the like.

Then, referring to step S4 in fig. 2 and fig. 10, forming a second conductive bump 18 on the plastic intermediate 10, where the second conductive bump 18 is located on one side of the front surface 14a of the plastic package layer and connected to the second pad 121, forming a conductive layer 17 on the side wall and the bottom wall of the via hole 16 and the front surface 14a of the plastic package layer outside the via hole 16, and the second conductive bump 18 connected to the second pad 121 is connected to the conductive layer 17 on the front surface 14a of the plastic package layer; the second conductive bump 18 is formed and a heat dissipation electrode 19 is formed, and the heat dissipation electrode 19 is connected to the thermal conductive paste 13.

Before forming the second conductive bump 18, an opening exposing the second pad 121 and the thermal conductive paste 13 is formed in the leveling layer 20.

In this embodiment, in the second die 12, the second protection layer 122 has a second opening exposing the second pad 121, so that a partial thickness of the leveling layer 20 is removed by a laser drilling method, and the remaining thickness is maintained, which may be 3 μm to 5 μm; a plasma clean (plasma clean) is then used to remove a portion of the thickness to expose the second pad 121. The energy of the plasma cleaning method is lower than that of the laser hole-opening method, so that the second pad 121 is prevented from being damaged when the second pad 121 is exposed by the laser hole-opening method.

In addition, in order to prevent the leveling layer 20 and the molding layer 14 from being damaged by the plasma cleaning method, a metal mask layer may be formed on the front surfaces of the leveling layer 20 and the molding layer 14, and the material of the metal mask layer may be copper. After the second pad 121 is exposed, the metal mask layer is removed.

Forming the opening exposing the thermal conductive paste 13 in the planarization layer 20 may refer to a forming method of the opening forming the second pad 121.

The second conductive bump 18 may be completed using an electroplating process. The process of electroplating copper or aluminum is mature. In this embodiment, the second conductive bump 18 is a front-to-outer connection terminal of the MCM package structure 1.

In other embodiments, an oxidation resistant layer may also be formed on the second conductive bump 18.

The oxidation resistant layer may include: b1) tin layer, or b2) nickel layer and gold layer stacked from bottom to top, or b3) nickel layer, palladium layer and gold layer stacked from bottom to top. The oxidation resistant layer may be formed using an electroplating process. The material of the second conductive bump 18 may be copper, and the anti-oxidation layer may prevent oxidation of copper, thereby preventing degradation of electrical connection performance due to oxidation of copper.

A second dielectric layer embedding the second redistribution layer may be disposed on the back surface 14b of the molding layer 14. In other words, the MCM package structure has only front-to-exterior connection ends.

In some embodiments, a second conductive bump 18 may be disposed on the second redistribution layer, and the second conductive bump 18 is exposed outside the second dielectric layer and still serves as a front-to-outside connection terminal.

After the second conductive bump 18 is formed, as shown in fig. 11, the supporting plate 31 is removed.

The removing method of the support plate 31 may be a conventional removing method such as laser lift-off, UV irradiation, or the like.

Thereafter, referring to step S5 in fig. 2, fig. 11 and fig. 1, a plurality of MCM package structures 1 are formed by dicing.

Each MCM package 1 includes a set of components to be molded 40.

In other embodiments, the second conductive bump 18 may be formed first, and then the first conductive bump 15 is formed, and the via 16 exposes the second conductive bump 18.

Fig. 12 is a schematic cross-sectional structure diagram of an MCM package structure of the second embodiment of the invention.

Referring to fig. 12 and 1, MCM package structure 2 in the present embodiment differs from MCM package structure 1 in the first embodiment only in that: the via 16 and the conductive layer 17 at the inner wall of the via 16 are replaced by a conductive plug 21. In other words, the MCM package structure 2 employs the conductive plugs 21 as an electrical connection structure to electrically connect the first die 11 and the second die 12.

Fig. 13 is a flow chart of a method of fabricating the MCM package structure of fig. 12. Referring to fig. 13 and 2, the method for manufacturing the MCM package structure 2 in the present embodiment differs from the method for manufacturing the MCM package structure 1 in the first embodiment only in that: step S3', forming a conductive plug 21 in the molding layer 14, where the conductive plug 21 includes a first end 21a and a second end 21b opposite to each other, and the first end 21a is connected to the formed first conductive bump 15; in step S4', a second conductive bump 18 is formed on the second ends of the plastic intermediate 10 and the conductive plug 21, and the second conductive bump 18 is located on one side of the front surface 14a of the plastic layer and at least connects the conductive plug 21 and the at least one second pad 121.

The forming method of the conductive plug 21 may include: an opening is formed in the plastic package layer 14 by a laser opening method, and then a conductive layer is filled in the opening by an electroplating method.

In addition to the above differences, other structures of MCM package structure 2 and other steps of its fabrication method in the present embodiment may refer to other structures of MCM package structure 1 and other steps of its fabrication method of the foregoing embodiment.

Fig. 14 is a schematic cross-sectional structure view of an MCM package structure of a third embodiment of the invention.

Referring to fig. 14, 1 and 12, MCM package 3 in the present embodiment differs from MCM packages 1 and 2 in embodiments one and two only in that: the vias 16 and the conductive layer 17 at the inner walls of the vias 16 are replaced with conductive pillars 22. In other words, the MCM package structure 3 achieves electrical connection of the first die 11 and the second die 12 using the conductive pillars 22 as an electrical connection structure.

Fig. 15 is a flowchart of a method of fabricating the MCM package structure of fig. 14. Referring to fig. 15, 2 and 13, the method for manufacturing MCM package structure 3 in the present embodiment differs from the method for manufacturing MCM package structures 1 and 2 in the first and second embodiments only in that: step S1', the plastic package intermediate 10 includes: a conductive post 22; the molding compound layer 14 encapsulates the conductive pillars 22, the front surface 14a of the molding compound layer 14, the active surface 12a of the second die 12, and the first ends 22a of the conductive pillars 22 face the same direction, and the back surface 14b of the molding compound layer 14, the active surface 11a of the first die 11, and the second ends 22b of the conductive pillars 22 face the same direction; step S2', the first conductive bump 15 is located on the backside 14b of the molding compound layer, and at least connects the conductive pillar 22 and the at least one first pad 111; step S3 is omitted; in step S4', the second conductive bump 18 is located on the front surface 14a of the molding layer and at least connects the conductive pillar 22 with the at least one second pad 121.

In other words, in the method for forming the plastic package intermediate 10, each group of the to-be-molded components 40 includes the conductive pillars 22 in addition to the first die 11 and the second die 12.

In addition to the above differences, other structures of MCM package structure 3 and other steps of the method of fabricating the same in the present embodiment may refer to other structures of MCM package structures 1, 2 and other steps of the method of fabricating the same in the foregoing embodiments.

Fig. 16 is a schematic cross-sectional structure view of an MCM package structure of a fourth embodiment of the invention.

Referring to fig. 16, 1, 12 and 14, MCM package 4 in the present embodiment differs from MCM packages 1, 2 and 3 in embodiments one, two and three only in that: the first die 11 includes a first back electrode 113, the first back electrode 113 being located on the back surface 11b of the first die 11; the second die 12 includes a second back electrode 123, the second back electrode 123 being located on the back side 12b of the second die 12; the heat conductive adhesive 13 has a conductive function, and the heat dissipation electrode 19 is used for electrically connecting a fixed potential.

When the first die 11 and the second die 12 are IGBT dies, the first back electrode 113 and the second back electrode 123 are drains, and may be grounded.

The thermally conductive paste 13 having an electrically conductive function may include a nano copper/electrically conductive polymer composite material. The nano-copper/conductive polymer composite material is a composite material formed by adding nano-copper particles into a conductive polymer and uniformly dispersing nano-copper in the conductive polymer.

When the nano copper/conductive polymer composite material is disposed in the accommodating groove 110, the nano copper/conductive polymer composite material is a solid flat sheet structure. The conductive polymer material can be heated to a temperature above the glass transition temperature; at this time, the conductive polymer material changes from a solid to a semi-liquid with a certain viscosity, bonding the first die 11 and the second die 12 together.

In the nano copper/conductive polymer composite material, the conductive polymer can be: at least one of polypyrrole, polythiophene, polyaniline and polyphenylene sulfide. The conductive polymer is formed by chemically or electrochemically doping high molecules with conjugated pi-bonds to convert the high molecules from insulators to conductors, and the conductive polymer has good conductive characteristics and is further enhanced in conductivity after nano copper is added.

The copper material is one of the metal materials with the most excellent electrical conductivity, and when the size of copper is reduced to the nanometer level, the copper material has more excellent electrical and thermal conductivity due to large specific surface area and high surface activity. Preferably, the nano copper is spherical, and the particle size is less than 800 nm; more preferably, the particle size of the nano-copper is in the range of 200nm to 500 nm. This is because: the specific surface area of the nano copper material is increased along with the reduction of the particle size of the material, and the electric and heat conduction properties of the material are enhanced; when the particle size is reduced to be below 800nm, the material has excellent electric and heat conduction characteristics; however, when the particle size is further reduced to below 200nm, the cost of the nano material is significantly increased, which affects the economic benefit of the package, and when the particle size of the nano copper is reduced to below 200nm, the surface energy of the nano copper particles is increased, and the particles are easy to agglomerate to form larger particles, which may impair the conductive and heat conductive properties of the composite material.

Preferably, the nano copper is added in an amount of more than 5 wt% in the nano copper/conductive polymer composite material.

In addition to the above differences, other structures of MCM package structure 4 in the present embodiment may refer to other structures of MCM package structures 1, 2 of the foregoing embodiments.

As a method for manufacturing the MCM package structure 4, reference may be made to the methods for manufacturing the MCM package structures 1, 2, and 3 in embodiments one, two, and three.

Fig. 17 is a schematic cross-sectional structure diagram of an MCM package structure of a fifth embodiment of the invention.

Referring to fig. 17, 16, 1, 12 and 14, MCM package 5 in the present embodiment differs from MCM packages 1, 2, 3 and 4 in embodiments one, two, three and four only in that: the receiving groove 110 is stepped.

In this embodiment, the first recess 110a may be formed in the back surface 11b of the first die 11, and then the second recess 110b may be formed in the first recess 110 a. The second groove 110b has a depth greater than that of the first groove 110a, the second groove 110b is a receiving groove 110, and the first groove 110a may be used to define an area of the thermal conductive paste 13.

In other embodiments, a third groove, …, may be further formed in the second groove 110 b. The third grooves have a greater depth than the second grooves 110b, ….

In addition to the above differences, other structures of MCM package structure 5 and other steps of the method of fabricating the same in the present embodiment may refer to other structures of MCM package structures 1, 2, 3, 4 and other steps of the method of fabricating the same in the foregoing embodiments.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

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