阅读说明：本技术 一种超薄扇出型封装结构及其制作方法 (Ultrathin fan-out type packaging structure and manufacturing method thereof ) 是由 李恒甫 曹立强 于 2019-08-29 设计创作，主要内容包括：本申请提供一种超薄扇出型封装结构及其制作方法。上述超薄扇出型封装结构包括：背面相互贴合的第一芯片和第二芯片,所述第一芯片背面的衬底经过减薄处理；塑封体,所述塑封体包封所述第一芯片和所述第二芯片；重布线结构,设置在所述塑封体靠近所述第一芯片的一侧,所述重布线结构分别与所述第一芯片和第二芯片电连接。本申请提供的超薄扇出型封装结构,通过将第一芯片、第二芯片背面相互贴合,并至少对第一芯片背面的衬底进行减薄处理,通过塑封体包封第一芯片和第二芯片,且与重布线结构连接,大大减小了封装结构整体的厚度,实现了高密度的超薄扇出型封装,有利于尺寸更小的电子产品的加工与生产。(The application provides an ultrathin fan-out type packaging structure and a manufacturing method thereof. The ultrathin fan-out package structure comprises: the chip comprises a first chip and a second chip, wherein the back surfaces of the first chip and the second chip are mutually attached, and a substrate on the back surface of the first chip is thinned; a plastic package body encapsulating the first chip and the second chip; and the rewiring structure is arranged on one side of the plastic package body close to the first chip and is electrically connected with the first chip and the second chip respectively. The application provides an ultra-thin fan-out type packaging structure, through laminating first chip, the second chip back each other to at least carrying out the attenuate to the substrate at the first chip back and handling, encapsulate first chip and second chip through the plastic-sealed body, and with rewiring structural connection, reduced the holistic thickness of packaging structure greatly, realized the encapsulation of the ultra-thin fan-out type of high density, be favorable to the processing and the production of the electronic product that the size is littleer.)

1. An ultra-thin fan-out package structure, comprising:

the chip comprises a first chip (1) and a second chip (2) with the back surfaces attached to each other, wherein a substrate on the back surface of the first chip (1) is thinned;

a plastic package body (3), the plastic package body (3) encapsulating the first chip (1) and the second chip (2);

and the rewiring structure is arranged on one side, close to the first chip (1), of the plastic package body (3), and is electrically connected with the first chip (1) and the second chip (2) respectively.

2. The ultra-thin fan-out package structure of claim 1, wherein the molding compound (3) has a first surface and a second surface opposite to the first surface,

the front surface of the first chip (1) is flush with the first surface of the plastic package body (3), and the front surface of the second chip (2) is flush with the second surface of the plastic package body (3).

3. The ultra-thin fan-out package structure of claim 2, further comprising:

the first conductive interconnection structure (9) penetrates through the plastic package body (3) along the arrangement direction of the first chip (1) and the second chip (2), and the first conductive interconnection structure (9) is a conductive column or a conductive through hole;

a second conductive interconnection structure (10) arranged on one side of the plastic package body (3) close to the second surface, the second conductive interconnection structure (10) is respectively connected with the front surface of the second chip (2) and the first conductive interconnection structure (9),

the second chip (2) is connected with the rewiring structure sequentially through the second conductive interconnection structure (10) and the first conductive interconnection structure (9).

4. The ultra-thin fan-out package structure of any of claims 1-3, wherein the rewiring structure comprises:

a solder structure (4) having one end electrically connected to the first chip (1) or the second chip (2) and the other end electrically connected to a first conductive pad (5);

an external solder ball (6) connected with the second conductive pad (7);

a conductive transfer structure connecting the first conductive pad (5) and the second conductive pad (7).

5. The ultra-thin fan-out package structure of any of claims 1-4, characterized in that the substrate on the back side of the second chip (2) is thinned.

6. A method of fabricating the ultra thin fan-out package structure of any of claims 1 to 5, comprising:

providing a first carrier (16), inversely installing a first chip (1) on the first carrier (16), and manufacturing a plastic package body (3) to encapsulate the first chip (1);

thinning the substrate on the back surface of the first chip (1) to form a cavity (18) on the plastic package body (3) at one side close to the back surface of the first chip (1);

manufacturing a first conductive interconnection structure (9) penetrating through the plastic package body (3) in the plastic package body (3) along the arrangement direction of the first chip (1) and the second chip (2);

placing a second chip (2) in the cavity (18) to enable the back surface of the second chip (2) to be attached to the back surface of the first chip (1);

manufacturing a second conductive interconnection structure (10) on one side of the plastic package body (3) close to the second chip (2), and connecting the second chip (2) and the first conductive interconnection structure (9) through the second conductive interconnection structure (10);

and removing the first carrier (16), and manufacturing a rewiring structure on one side of the plastic package body (3) close to the first chip (1) so as to respectively connect the rewiring structure with the first chip (1) and the first conductive interconnection structure (9).

7. The method for manufacturing an ultra-thin fan-out package structure according to claim 6, wherein the substrate on the back side of the first chip (1) is thinned by dry etching or wet etching.

8. Method of manufacturing an ultra thin fan out package structure according to claim 6 or 7, characterized in that a filler (19) is made in the gap between the second chip (2) and the cavity (18).

9. The method of fabricating the ultra thin fan-out package structure of any of claims 6 to 8, wherein the method of fabricating the second conductive interconnect structure (10) comprises:

respectively manufacturing a first transfer line (12) on the second chip (2) and the first conductive interconnection structure (9);

conductive pieces (13) are respectively connected to the first transfer lines (12);

and connecting the conductive member (13) connected with the second chip (2) and the conductive member (13) connected with the first conductive interconnection structure (9) through a second transfer line (14).

10. The method for fabricating the ultra-thin fan-out package structure of any of claims 6-9, wherein the method for fabricating the redistribution structure comprises:

respectively manufacturing a welding structure (4) on the first chip (1) and the first conductive interconnection structure (9);

providing a second carrier (20), and sequentially preparing a second conductive pad (7), a conductive transfer structure and a first conductive pad (5) on the second carrier (20), wherein the second conductive pad (7) is connected with the first conductive pad (5) through the conductive transfer structure;

-welding said second conductive pad (7) with said welding structure (4);

and removing the second carrier (20), and manufacturing an external solder ball (6) on the first conductive pad (5).

Technical Field

The invention relates to the technical field of semiconductor packaging, in particular to an ultrathin fan-out packaging structure and a manufacturing method thereof.

Background

With the rapid development of integrated circuit technology, the number of chips per unit area of a wafer is increasing, and the feature size of the chip is gradually miniaturized to meet the requirement of moore's law. Although chip feature sizes decrease, the number of electronic components (including resistors, capacitors, diodes, transistors, etc.) within the chip continues to increase. In order to realize the application of chip functions to product terminals, a packaging technology with compact packaging size and more output terminal I/O quantity is required in the packaging field. To meet the requirement, a Fanout wafer level Package (FOWLP) is developed, and this Package type implements connection of a plurality of terminals outside the chip feature size area through wire transfer, and has the advantages of a thinner Package structure and lower cost. In addition, with the more and more prominent demands for higher chip packaging density and smaller occupied area, electrical signal interconnection of multiple layers of chips is realized by stacking multiple chips and using an interconnection structure, i.e., a three-dimensional packaging structure is also widely applied and developed.

Chinese patent document (CN107910310A) discloses a multi-chip fan-out packaging structure and a packaging method thereof, wherein the multi-chip fan-out packaging structure comprises an A chip with an A chip metal bump, a wiring layer, an A chip coating film, a B chip with a B chip metal bump, a rewiring layer and a B chip coating film, the B chip is arranged in a region vertically above the A chip, a through hole is arranged in a region outside the B chip, metal materials are filled in the through hole, and the A chip and the B chip are connected with each other through the wrapped through hole, the metal materials, the wiring layer and the rewiring layer. Above-mentioned multi-chip fan-out packaging structure is mainly formed by two encapsulation bodies that pile up from top to bottom, and packaging structure's thickness is two-layer chip and two-layer metal lug and the sum of two-layer wiring layer at least, can't realize the requirement of ultra-thin fan-out type encapsulation, and in addition, need carry out the plastic envelope to A chip and B chip respectively when making above-mentioned packaging structure, the step is loaded down with trivial details, is unfavorable for industry large-scale production.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is to overcome the defects that the fan-out type packaging structure in the prior art is large in thickness and cannot meet the requirement of ultrathin fan-out type packaging, thereby providing an ultrathin fan-out type packaging structure.

The invention also aims to overcome the defects that the packaging method in the prior art needs to carry out plastic packaging for multiple times, has complicated steps and is not beneficial to industrial large-scale production, thereby providing the packaging method of the ultrathin fan-out type packaging structure, which only needs to carry out plastic packaging for one time.

A first aspect of the present invention provides an ultra-thin fan-out package structure, including:

the chip comprises a first chip and a second chip, wherein the back surfaces of the first chip and the second chip are mutually attached, and a substrate on the back surface of the first chip is thinned;

a plastic package body encapsulating the first chip and the second chip;

and the rewiring structure is arranged on one side of the plastic package body close to the first chip and is electrically connected with the first chip and the second chip respectively.

Further, the plastic package body is provided with a first surface and a second surface opposite to the first surface,

the front surface of the first chip is flush with the first surface of the plastic package body, and the front surface of the second chip is flush with the second surface of the plastic package body.

Further, the ultra-thin fan-out package structure further comprises:

the first conductive interconnection structure penetrates through the plastic package body along the arrangement direction of the first chip and the second chip, and the first conductive interconnection structure is a conductive column or a conductive through hole;

a second conductive interconnection structure disposed on a side of the plastic package body near the second surface, the second conductive interconnection structure being connected to the front surface of the second chip and the first conductive interconnection structure respectively,

the second chip is connected with the rewiring structure sequentially through the second conductive interconnection structure and the first conductive interconnection structure.

Further, the rewiring structure includes:

one end of the welding structure is electrically connected with the first chip or the second chip, and the other end of the welding structure is electrically connected with the first conductive pad;

the external solder ball is connected with the second conductive pad;

a conductive transfer structure connecting the first and second conductive pads.

Further, the substrate on the back of the second chip is thinned.

The invention provides a manufacturing method of an ultrathin fan-out type packaging structure, which comprises the following steps:

providing a first carrier, inversely installing a first chip on the first carrier, and manufacturing a plastic package body to encapsulate the first chip;

thinning the substrate on the back of the first chip to form a cavity on one side of the plastic package body close to the back of the first chip;

manufacturing a first conductive interconnection structure penetrating through the plastic package body in the arrangement direction of the first chip and the second chip in the plastic package body;

placing a second chip in the cavity, and enabling the back surface of the second chip to be attached to the back surface of the first chip;

manufacturing a second conductive interconnection structure on one side of the plastic package body close to the second chip, and connecting the second chip and the first conductive interconnection structure through the second conductive interconnection structure;

and removing the first carrier, and manufacturing a rewiring structure on one side of the plastic package body close to the first chip, so that the rewiring structure is respectively connected with the first chip and the first conductive interconnection structure.

Further, the substrate on the back side of the first chip is thinned through a dry etching method or a wet etching method.

Further, a filler is made in a gap between the second chip and the cavity.

Further, the method for manufacturing the second conductive interconnection structure comprises the following steps:

respectively manufacturing a first transfer line on the second chip and the first conductive interconnection structure;

the first transfer lines are respectively connected with conductive pieces;

and connecting the conductive piece connected with the second chip and the conductive piece connected with the first conductive interconnection structure through a second transfer line.

Further, the method of fabricating the re-wiring structure includes:

respectively manufacturing welding structures on the first chip and the first conductive interconnection structure;

providing a second carrier, and sequentially preparing a second conductive pad, a conductive transfer structure and a first conductive pad on the second carrier, wherein the second conductive pad is connected with the first conductive pad through the conductive transfer structure;

welding the second conductive pad to the weld structure;

and removing the second carrier, and manufacturing an external solder ball on the first conductive pad.

The technical scheme of the invention has the following advantages:

1. according to the ultrathin fan-out type packaging structure provided by the invention, the backs of the first chip and the second chip are mutually attached, the substrate on the back of the first chip is at least thinned, the first chip and the second chip are packaged by the plastic package body and are connected with the rewiring structure, the integral thickness of the packaging structure is greatly reduced, the high-density ultrathin fan-out type packaging is realized, and the processing and the production of electronic products with smaller sizes are facilitated.

2. According to the ultrathin fan-out type packaging structure provided by the invention, the front surface of the first chip is controlled to be flush with the first surface of the plastic packaging body, and the second chip is controlled to be flush with the second surface of the plastic packaging body, so that the thickness of the plastic packaging body is equal to the sum of the thicknesses of the first chip and the second chip, and the thickness of the whole packaging structure is thinner.

3. The ultrathin fan-out packaging structure provided by the invention is provided with the first conductive interconnection structure and the second conductive interconnection structure, so that the second chip is connected with the rewiring structure, and compared with a routing connection mode with higher space requirement, the ultrathin fan-out packaging structure has the advantages of higher reliability, higher density and more compact structure.

4. According to the ultrathin fan-out type packaging structure, the substrate on the back of the second chip is thinned before packaging, so that the thickness of the whole packaging structure can be further reduced.

5. According to the manufacturing method of the ultrathin fan-out type packaging structure, the substrate on the back face of the first chip is thinned on the whole face after the first chip is packaged, and the cavity for accommodating the second chip is formed in the plastic packaging body, so that the back faces of the first chip and the second chip are attached to each other ingeniously, the thickness of a connecting medium between the first chip and the second chip is omitted, and the thickness of the plastic packaging body is basically equal to the sum of the thicknesses of the first chip and the second chip; the second conductive interconnection structure is manufactured on one side, close to the second chip, of the plastic package body and connected with the first conductive interconnection structure penetrating through the plastic package body, interconnection of the second chip and the rewiring structure is achieved, and connection is reliable and stable.

6. According to the manufacturing method of the ultrathin fan-out type packaging structure, after the second chip is placed in the cavity, the gap between the second chip and the cavity is filled through the filling body, so that the second chip is firmer, the thickness of the packaging structure cannot be increased, and the packaging is stable and reliable.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic structural diagram of an ultra-thin fan-out package structure according to an embodiment of the present disclosure;

FIG. 2 is a schematic flow chart illustrating a method for fabricating an ultra-thin fan-out package structure according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram obtained in step S1 in this embodiment of the present application;

fig. 4 is a schematic structural diagram obtained in step S2 in the embodiment of the present application;

fig. 5 is a schematic structural diagram obtained in step S3 in this embodiment of the present application;

fig. 6 is a schematic structural diagram obtained in step S4 in this embodiment of the present application;

fig. 7 is a schematic structural diagram obtained in step S5 in the embodiment of the present application;

fig. 8 is a schematic structural diagram of a welded structure manufactured in step S6 in the embodiment of the present application;

fig. 9 is a schematic structural diagram illustrating a second conductive pad, a conductive transfer structure, and a first conductive pad fabricated in step S6 according to an embodiment of the present invention;

fig. 10 is a schematic structural diagram illustrating a structure obtained by welding the second conductive pad and the welding structure in step S6 according to an embodiment of the present invention.

Description of reference numerals:

1-a first chip; 2-a second chip; 3-plastic packaging body; 4-welding the structure; 5-a first conductive pad; 6-external solder ball; 7-a second conductive pad; 8-a first insulating dielectric body; 9-a first conductive interconnect structure; 10-a second conductive interconnect structure; 11-a second insulating dielectric body; 12-a first transfer line; 13-a conductive member; 14-a second transfer line; 15-a third transfer line; 16-a first slide; 17-a first adhesive layer; 18-a cavity; 19-a filler; 20-a second slide; 21-second adhesive layer.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

In a first aspect, an embodiment of the invention provides an ultra-thin fan-out package structure.

As shown in fig. 1, the ultra-thin fan-out package structure includes: the back surfaces of the first chip 1 and the second chip 2 are mutually attached, and the substrate on the back surface of the first chip 1 is thinned; the plastic package body 3 is used for encapsulating the first chip 1 and the second chip 2; and the rewiring structure is arranged on one side of the plastic package body 3 close to the first chip 1 and is electrically connected with the first chip 1 and the second chip 2 respectively.

The ultra-thin fan-out type packaging structure that this embodiment provided, through laminating first chip 1, 2 backs of second chip each other, and carry out the attenuate processing to the substrate at the 1 back of first chip at least, encapsulate first chip 1 and second chip 2 through the plastic-sealed body 3, and be connected with rewiring structure, the holistic thickness of packaging structure has been reduced greatly, the ultra-thin fan-out type encapsulation of high density has really been realized, be favorable to the processing and the production of the electronic product that the size is littleer.

The first chip 1 and the second chip 2 include, but are not limited to: active devices such as a central processing unit, a graphic processor, a memory array and an image sensor, or passive devices such as an inductor and a resistor.

The substrate on the back of the first chip 1 can be thinned by a dry etching or wet etching method, the thickness of the first chip 1 can be thinned from more than 200um to the thickness of the residual silicon which is about 3um, the silicon substrate can be completely removed for the chip with the SOI structure and stays at the position of an SOI oxide layer, and the whole thickness of the packaging structure is obviously reduced by thinning the first chip 1.

As a further improvement of this embodiment, the substrate on the back side of the second chip 2 is subjected to thinning processing.

The substrate on the back of the second chip 2 is thinned before packaging, so that the whole thickness of the packaging structure can be further reduced, and the ultrathin fan-out type packaging structure is provided.

The molding compound 3 is used for encapsulating the first chip 1 and the second chip 2, and may be made of epoxy resin or other materials, and the material of the molding compound 3 may or may not contain particle fillers.

Preferably, the plastic package body 3 has a first surface and a second surface opposite to the first surface, the front surface of the first chip 1 is flush with the first surface of the plastic package body 3, and the front surface of the second chip 2 is flush with the second surface of the plastic package body 3.

Specifically, the plastic package body 3 may be planarized and reduced in height by processes such as grinding, chemical etching, UV illumination, and the like, so that a first surface thereof is flush with the front surface of the first chip 1 and exposes the front surface of the first chip 1, and a second surface thereof is flush with the front surface of the second chip 2 and exposes the front surface of the second chip 2.

By controlling the front surface of the first chip 1 to be flush with the first surface of the plastic package body 3 and the second chip 2 to be flush with the second surface of the plastic package body 3, the thickness of the plastic package body 3 is equal to the sum of the thicknesses of the first chip 1 and the second chip 2, and the thickness of the whole packaging structure is thinner.

The rewiring structure, that is, a structure for conducting signals between the first chip 1 and the second chip 2 and other devices (such as a PCB), realizes fan-out packaging of the first chip 1 and the second chip 2. As a preferable aspect of the present embodiment, the rewiring structure includes: a solder structure 4 having one end electrically connected to the first chip 1 or the second chip 2 and the other end electrically connected to the first conductive pad 5; an external solder ball 6 connected to the second conductive pad 7; a conductive transfer structure connecting the first conductive pad 5 and the second conductive pad 7.

Specifically, the soldering structure 4 may be in the form of a conductive post, a conductive bump, or the like, and may be made of a metal such as copper, nickel, tin, silver, gold, or the like, and may be made by electroplating, chemical plating, or other methods; the first conductive pad 5, the second conductive pad 7 and the conductive transfer structure are encapsulated in a first insulating dielectric body 8, the first insulating dielectric body 8 is composed of multiple layers of insulating dielectric layers (not shown in the figure) and is respectively used for encapsulating the first conductive pad 5, the second conductive pad 7, the conductive transfer structure and the like, the materials of the first insulating dielectric body 8 can be inorganic materials such as silicon oxide, silicon oxynitride, borosilicate glass, Phosphorus Silicate Glass (PSG), borophosphosilicate glass (BPSG), fluorinated glass silicate glass (FSG), low-K dielectric and the like or organic materials such as Polyimide (PI), poly-p-Phenylene Benzobisoxazole (PBO) and the like, and the materials of the insulating dielectric layers are the same or different; the shapes, sizes, and thicknesses of the first conductive pad 5 and the second conductive pad 7 are not limited in this application, and may be, for example, sheets, blocks, columns, etc., the conductive transfer structure is used to redistribute the external solder balls 6, and may be a transfer line structure or a transfer line plus conductive via/conductive pillar structure, etc., the first conductive pad 5, the second conductive pad 7, the transfer line, the conductive via/conductive pillar are made of conductive metal, and the material thereof may be copper, aluminum, tungsten, nickel, gold, etc.; the external solder balls 6 may be made of copper, nickel, tin, silver, etc.

The soldering structure 4 is electrically connected to the first chip 1 or the second chip 2 through a conductive interconnection structure, such as a wire bonding connection or other conductive structure. As a preference of this embodiment, the ultra-thin fan-out package structure further includes: the first conductive interconnection structure 9 penetrates through the plastic package body 3 along the arrangement direction of the first chip 1 and the second chip 2, and the first conductive interconnection structure 9 is a conductive column or a conductive through hole; the second conductive interconnection structure 10 is arranged on one side, close to the second surface, of the plastic package body 3, the second conductive interconnection structure 10 is respectively connected with the front face of the second chip 2 and the first conductive interconnection structure 9, and the second chip 2 is connected with the welding structure 4 sequentially through the second conductive interconnection structure 10 and the first conductive interconnection structure 9.

Specifically, the first conductive interconnection structure 9 is a conductive post or a conductive through hole penetrating through the first surface and the second surface of the plastic package body 3, and the material thereof may be metal such as copper, aluminum, tungsten, titanium, and the like, and is embedded in the plastic package body 3; the second conductive interconnection structure 10 includes a second insulating dielectric body 11, and a first transfer line 12, a conductive member 13, and a second transfer line 14 encapsulated in the second insulating dielectric body 11, the second insulating dielectric body 11 is composed of multiple insulating dielectric layers (not shown in the figure) for respectively encapsulating the first transfer line 12, the conductive member 13, and the second transfer line 14, the material of the insulating dielectric layers may be inorganic materials such as silicon dioxide, silicon nitride, and silicon oxynitride, or organic materials such as poly-p-Phenylene Benzobisoxazole (PBO), Polyimide (PI), and benzocyclobutene (BCB), the material of each insulating dielectric layer is the same or different, the first transfer line 12 is respectively connected to the front surface of the second chip 2 and one end of the first conductive interconnection structure 9 close to the second surface of the plastic encapsulated body 3, the end of the first transfer line 12 not connected to the second chip 2 or the first conductive interconnection structure 9 is connected to the conductive member 13, the conductive piece 13 is a conductive column or a conductive through hole structure, one end of the second transfer line 14 is connected with the conductive piece 13 connected with the second chip 2, the other end of the second transfer line is connected with the conductive piece 13 connected with the first conductive interconnection structure 9, the first transfer line 12, the second transfer line 14 and the conductive piece 13 can be made of metal materials such as copper, tungsten and aluminum, so that the second chip 2 is connected with the first conductive interconnection structure 9, and the second chip 2 is connected with the welding structure 4 through the second conductive interconnection structure 10 and the first conductive interconnection structure 9.

The welding structure 4 can be directly connected with the front surface of the first chip 1 or one end, close to the first surface of the plastic package body 3, of the first conductive interconnection structure 9, and can also be connected through a third transfer line 15, one end of the third transfer line 15 is connected with the welding structure 4, the other end of the third transfer line is connected with the front surface of the first chip 1 or one end, close to the first surface of the plastic package body 3, of the first conductive interconnection structure 9, and whether the third transfer line 15 is arranged or not can be selected according to actual packaging requirements.

Through setting up the electrically conductive interconnect structure of first electrically conductive 9 and the electrically conductive interconnect structure of second 10, realize that second chip 2 is connected with rewiring structure, compare in the higher routing connected mode of space requirement, the reliability is stronger, and density is bigger, and the structure is compacter.

In a second aspect, an embodiment of the invention provides a method for manufacturing an ultra-thin fan-out package structure.

As shown in FIG. 2, the above manufacturing method includes steps S1-S6, which are specifically described as follows:

step S1, providing the first carrier 16, and flip-chip mounting the first chip 1 on the first carrier 16, so as to fabricate the plastic package body 3 to encapsulate the first chip 1. The structure obtained in step S1 is shown in fig. 3.

The first carrier 16 may be made of silicon, gallium arsenide, silicon carbide, glass, or the like, the front surface of the first chip 1 is connected to the first carrier 16 through a first adhesive layer 17, and the material of the first adhesive layer 17 may be a polymer material, UV glue, or other materials.

The plastic package body 3 can be made by coating epoxy resin and curing, and preferably, planarization and height reduction are achieved by grinding, chemical etching, UV irradiation, and other processes, so that the back surface of the first chip 1 is flush with the upper surface of the plastic package body 3 and the back surface of the first chip 1 is exposed.

In step S2, the substrate on the back surface of the first chip 1 is thinned to form the cavity 18 on the side of the plastic package body 3 close to the back surface of the first chip 1. The structure obtained in step S2 is shown in fig. 4.

Preferably, the substrate on the back surface of the first chip 1 is thinned by dry etching or wet etching, the area of the bottom surface of the cavity 18 is equivalent to the area of the first chip 1, and the height of the cavity 18 can be controlled to be equal to the thickness of the second chip 2.

Step S3, a first conductive interconnection structure 9 penetrating through the plastic package body 3 is fabricated in the plastic package body 3 along the arrangement direction of the first chip 1 and the second chip 2. The structure obtained in step S3 is shown in fig. 5.

The first conductive interconnection structure 9 is located around the first chip 1, and through holes penetrating through the upper surface and the lower surface of the plastic package body 3 can be formed by a dry etching method or a wet etching method, and then a solid conductive pillar structure or a hollow conductive through hole structure is formed in the through holes.

In step S4, the second chip 2 is placed in the cavity 18, and the back surface of the second chip 2 is bonded to the back surface of the first chip 1. The structure obtained in step S4 is shown in fig. 6.

The second chip 2 is placed in the cavity 18 by picking, the front side of the second chip 2 faces upwards, the back side of the second chip 2 is opposite to the back side of the second chip, and the height of the second chip is consistent with the height of the cavity 18. Preferably, for the convenience of placement, the area of the second chip 2 is smaller than that of the first chip 1, a filler 19 is made in the gap between the second chip 2 and the cavity 18, and the material of the filler 19 may be epoxy resin with or without filler particles, other polymers or inorganic materials.

After the second chip 2 is placed in the cavity 18, the gap between the second chip 2 and the cavity 18 is filled with the filler 19, so that the second chip 2 is firmer, the thickness of the packaging structure is not increased, and the packaging is stable and reliable.

The second chip 2 is preferably subjected to a substrate thinning process before being placed in the cavity 18.

As another optional mode of this embodiment, the height of the second chip 2 is lower than the height of the cavity 18, and after the filling body 19 is manufactured, the plastic package body 3 is thinned by grinding, chemical etching, UV illumination, and other process manners, so that the front surface of the second chip 2 is flush with the upper surface of the plastic package body 3.

Step S5, a second conductive interconnection structure 10 is formed on a side of the plastic package body 3 close to the second chip 2, and the second chip 2 is connected to the first conductive interconnection structure 9 through the second conductive interconnection structure 10. The structure obtained in step S5 is shown in fig. 7.

As a preference of this embodiment, the method for manufacturing the second conductive interconnection structure 10 includes: respectively manufacturing a first transfer line 12 on the second chip 2 and the first conductive interconnection structure 9; the first transfer lines 12 are respectively connected with conductive pieces 13; the conductors 13 connected to the second chip 2 and the conductors 13 connected to the first conductive interconnection structures 9 are connected by a second transfer line 14.

Step S6, removing the first carrier 16, and fabricating a redistribution structure on a side of the plastic package body 3 close to the first chip 1, so that the redistribution structure is connected to the first chip 1 and the first conductive interconnection structure 9, respectively.

The first carrier 16 and the first adhesive layer 17 are peeled off by a debonding process, which may be realized by UV light, thermal decomposition bonding, mechanical debonding, and the like.

As a preferable aspect of this embodiment, the method of manufacturing the rewiring structure includes:

respectively manufacturing a welding structure 4 on the first chip 1 and the first conductive interconnection structure 9, as shown in fig. 8, connecting the welding structure 4 with the first chip 1 or the first conductive interconnection structure 9 through a third transfer line 15, wherein the third transfer line 15 may be a multilayer structure, and is not limited to the single-layer structure shown in the figure, and the welding structure 4 is manufactured by electroplating, chemical plating or other methods;

providing a second carrier 20, sequentially preparing a second conductive pad 7, a conductive transfer structure, and a first conductive pad 5 on the second carrier 20, wherein the second conductive pad 7 is connected to the first conductive pad 5 through the conductive transfer structure, as shown in fig. 9, the first conductive pad 5, the second conductive pad 7, and the conductive transfer structure are all fabricated and fixedly connected in an insulating dielectric layer, and the second conductive pad 7 is connected to the second carrier 20 through a second adhesive layer 21;

the second conductive pad 7 is soldered to the soldering structure 4, as shown in fig. 10, the soldering structure 4 and the second conductive pad 7 can be electrically connected by copper bonding, copper-tin bonding, reflow soldering, or other practical manners;

and removing the second carrier 20, and manufacturing an external solder ball 6 on the first conductive pad 5 to obtain the ultrathin fan-out packaging structure, wherein the second carrier 20 and the second adhesive layer 21 are removed through a bonding removal process, the external solder ball 6 is manufactured on the first conductive pad 5 to realize the electrical connection with the PBC board, and the external solder ball 6 can be manufactured in an electroplating or ball-planting manner.

It should be emphasized that the number of the first chips 1 is not limited to two shown in the figures, the second chips 2 are not limited to two shown in the figures, and in addition, other chips and the like can be stacked above the second chips, which can be selected and matched according to the actual situation, and the application is not limited thereto.

According to the manufacturing method of the ultrathin fan-out type packaging structure, the substrate on the back surface of the first chip 1 is thinned after the first chip is packaged, and the cavity 18 for accommodating the second chip 2 is formed in the plastic package body 3, so that the back surfaces of the first chip 1 and the second chip 2 are attached to each other skillfully, the thickness of a connecting medium between the first chip 1 and the second chip 2 is omitted, and the thickness of the plastic package body 3 is basically equal to the sum of the thicknesses of the first chip 1 and the second chip 2; the second conductive interconnection structure 10 is manufactured on one side, close to the second chip 2, of the plastic package body 3 and is connected with the first conductive interconnection structure 9 penetrating through the plastic package body 3, so that interconnection of the second chip 2 and the rewiring structure is achieved, and connection is reliable and stable.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.