CN114171404A - Packaging method and packaging structure of fan-out type stacked chip - Google Patents

Packaging method and packaging structure of fan-out type stacked chip Download PDF

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Publication number
CN114171404A
CN114171404A CN202111493899.1A CN202111493899A CN114171404A CN 114171404 A CN114171404 A CN 114171404A CN 202111493899 A CN202111493899 A CN 202111493899A CN 114171404 A CN114171404 A CN 114171404A
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chip
dummy
chips
layer
conductive
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杜茂华
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Tongfu Microelectronics Co Ltd
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Tongfu Microelectronics Co Ltd
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Priority to CN202111493899.1A priority Critical patent/CN114171404A/en
Publication of CN114171404A publication Critical patent/CN114171404A/en
Priority to PCT/CN2022/137246 priority patent/WO2023104094A1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
    • H01L21/56—Encapsulations, e.g. encapsulation layers, coatings
    • H01L21/568—Temporary substrate used as encapsulation process aid
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/16—Fillings or auxiliary members in containers or encapsulations, e.g. centering rings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
    • H01L23/31—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the arrangement or shape
    • H01L23/3107—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the arrangement or shape the device being completely enclosed
    • H01L23/3135—Double encapsulation or coating and encapsulation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/48—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
    • H01L23/481—Internal lead connections, e.g. via connections, feedthrough structures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/52—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames
    • H01L23/535—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including internal interconnections, e.g. cross-under constructions
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/02—Bonding areas ; Manufacturing methods related thereto
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L24/81—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a bump connector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/02—Bonding areas; Manufacturing methods related thereto
    • H01L2224/023—Redistribution layers [RDL] for bonding areas
    • H01L2224/0237—Disposition of the redistribution layers
    • H01L2224/02379—Fan-out arrangement
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/81—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a bump connector

Abstract

The invention provides a packaging method and a packaging structure of fan-out type stacked chips, wherein the method comprises the following steps: fixing a first chip in a groove body on a dummy chip, wherein the first chip and the dummy chip are both provided with a plurality of conductive through holes; respectively carrying out hot-press bonding on the plurality of second chips, the dummy chip and the first chip, wherein orthographic projections of the plurality of second chips on the dummy chip fall on the inner side of the dummy chip; forming a first plastic packaging layer, wherein the first plastic packaging layer wraps the plurality of second chips; forming a second plastic packaging layer, wherein the first chip, the dummy wafer and the first plastic packaging layer are wrapped by the second plastic packaging layer; and forming a rewiring layer on the surfaces of the dummy chip and the first chip, which are deviated from the plurality of second chips, wherein the rewiring layer is electrically connected with the first chip through the conductive through hole. According to the method, the first chip and the plurality of second chips are respectively expanded by the dummy chip and the first plastic package layer through a wafer expansion technology, and the plurality of second chips are respectively thermally and thermally bonded with the dummy chip and the first chip, so that the production efficiency is improved while high-density interconnection is realized.

Description

Packaging method and packaging structure of fan-out type stacked chip
Technical Field
The invention belongs to the technical field of semiconductor packaging, and particularly relates to a packaging method and a packaging structure of fan-out stacked chips.
Background
The electronic products have smaller and smaller volumes and stronger functions. With the consequent need for thinner and lighter semiconductor packages and higher interconnect densities. Conventional packages cannot meet future demands. Fig. 1 shows a typical conventional multilayer chip package structure, in which chips 1, 2 are vertically stacked on a substrate 6 via adhesive films 3, 4, and the chips 1, 2 are connected to the substrate 6 via gold wires 5. The chips 1, 2 and the gold wires 5 are protected by a molding compound 7. The whole package is connected to the outside by solder balls 8. In the current package, the height from the plastic package to the surface of the chip 2 is strictly limited due to the height limitation of the gold wire molding and the protection distance from the plastic package to the gold wire, and cannot be continuously reduced. Meanwhile, due to the limitation of materials and the limitation of substrate strength, the production difficulty of the ultrathin substrate is very high, and the application of the traditional package in ultrathin multilayer package is limited. And no matter the traditional routing connection or the reverse welding connection, the distance between the bonding pads is over 30um, and the difficulty of continuous reduction is extremely high.
In view of the above problems, there is a need for a package method and a package structure for fan-out stacked chips that are reasonable in design and can effectively solve the above problems.
Disclosure of Invention
The invention aims to at least solve one of the technical problems in the prior art and provides a fan-out stacked chip packaging structure and a packaging method.
One aspect of the present invention provides a packaging method of fan-out stacked chips, the method comprising:
fixing a first chip in a groove body on a dummy chip, wherein the first chip and the dummy chip are both provided with a plurality of conductive through holes;
respectively carrying out thermocompression bonding on a plurality of second chips and the dummy chip and the first chip, wherein orthographic projections of the plurality of second chips on the dummy chip fall on the inner side of the dummy chip;
forming a first plastic packaging layer, wherein the first plastic packaging layer wraps the plurality of second chips;
forming a second plastic packaging layer, wherein the second plastic packaging layer wraps the first chip, the dummy wafer and the first plastic packaging layer;
and forming a rewiring layer on the dummy chip and the surface of the first chip, which is far away from the plurality of second chips, wherein the rewiring layer is electrically connected with the first chip through the conductive through hole.
Optionally, the surfaces of the first chip and the dummy wafer facing the second chips are provided with a first passivation layer and a metal pad, and the surfaces of the second chips facing the first chip are provided with a second passivation layer and a plurality of conductive bumps;
the thermal compression bonding of the plurality of second chips with the dummy chip and the first chip respectively includes:
and carrying out thermocompression bonding on the metal bonding pad and the plurality of conductive bumps.
Optionally, before the thermocompression bonding of the second chip with the dummy chip and the first chip, respectively, the method further includes:
and forming a non-conductive adhesive layer which wraps the plurality of conductive bumps.
Optionally, before the thermocompression bonding of the second chip with the dummy chip and the first chip, respectively, the method further includes:
forming an adhesive glue on the surfaces of the dummy chip and the first chip, and filling part of the adhesive glue into a gap between the dummy chip and the first chip;
and removing the adhesive glue on the surfaces of the dummy wafer and the first chip to expose the first passivation layer and the metal bonding pad of the dummy wafer and the first chip.
Optionally, the forming the second plastic package layer includes:
thinning the surfaces of the bonded first chip and the bonded dummy wafer, which are far away from the plurality of second chips, to expose the conductive through holes of the first chip and the dummy wafer;
and fixing the thinned surfaces of the first chip and the dummy chip departing from the plurality of second chips onto a temporary carrier plate, and then forming the second plastic packaging layer.
Optionally, the forming a redistribution layer on the dummy chip and the surface of the first chip away from the plurality of second chips includes:
separating the first chip and the dummy wafer from the temporary carrier plate;
forming a dielectric layer on the surfaces of the second plastic packaging layer, the dummy chip and the first chip, which are far away from the plurality of second chips;
patterning the dielectric layer, and forming a rewiring layer on the patterned dielectric layer;
and patterning the redistribution layer, and forming solder balls on the patterned redistribution layer.
The invention provides a packaging structure of fan-out stacked chips, which comprises a first chip, a dummy wafer, a plurality of second chips, a hot-press bonding structure, a first plastic packaging layer, a second plastic packaging layer and a rewiring layer, wherein the dummy wafer is arranged on the first chip;
the dummy sheet is provided with a groove body, the groove body is provided with the first chip, and the first chip and the dummy sheet are both provided with a plurality of conductive through holes;
the second chips are arranged on the first chip and the dummy chip and are respectively connected with the dummy chip and the first chip in a hot-press bonding mode through the hot-press bonding structure, wherein orthographic projections of the second chips on the dummy chip fall on the inner side of the dummy chip;
the first plastic packaging layer wraps the plurality of second chips;
the second plastic packaging layer wraps the first chip, the dummy sheet and the first plastic packaging layer;
the rewiring layer is arranged on the dummy chip and the surface of the first chip, which is far away from the plurality of second chips, and the rewiring layer is electrically connected with the first chip through the conductive through hole.
Optionally, a first passivation layer and a metal pad are disposed on the surfaces of the first chip and the dummy wafer facing the plurality of second chips, and a second passivation layer and a plurality of conductive bumps are disposed on the surfaces of the plurality of second chips facing the first chip;
the thermocompression bonding structure comprises the metal pad and the plurality of conductive bumps, wherein the metal pad is connected with the plurality of conductive bumps in a thermocompression bonding manner.
Optionally, the dummy wafer is provided with the plurality of conductive through holes corresponding to at least part of the plurality of second chips.
Optionally, the plurality of conductive through holes are disposed at the plurality of second chips of the dummy wafer corresponding to the central region.
According to the packaging method and the packaging structure of the fan-out stacked chip, provided by the invention, the first chip and the second chips are respectively expanded by the dummy chip and the first plastic package layer through a wafer expansion technology, multi-chip signals are bridged, and the second chips are respectively in thermocompression bonding with the dummy chip and the first chip, so that the high-density interconnection is realized and the production efficiency is improved. The dummy wafer is used for transversely bridging the second chips, so that the packaging height is further reduced; a plurality of conductive through holes are formed in the dummy chip and the first chip, and a rewiring layer is formed on the surfaces of the dummy chip and the first chip, which are away from the second chip, so that the traditional substrate interconnection is replaced by a conductive through hole technology and a fan-out rewiring technology, and the packaging size is reduced; and direct wafer hot-press bonding is adopted among the second chips, the dummy chips and the first chip, so that the packaging height is further reduced. The packaging method provided by the invention realizes high density and ultra-thinness of the fan-out type stacked chip.
Drawings
FIG. 1 is a schematic diagram of a conventional multi-layered chip package structure according to the prior art;
FIG. 2 is a flow chart illustrating a method for packaging fan-out stacked chips according to another embodiment of the invention;
fig. 3 to 12 are schematic views illustrating a packaging process of fan-out stacked chips according to another embodiment of the invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
As shown in fig. 2, an aspect of the present invention provides a packaging method S100 for a fan-out stacked chip, where the packaging method S100 includes:
s110, fixing a first chip in a groove body on a dummy chip, wherein the first chip and the dummy chip are provided with a plurality of conductive through holes.
Specifically, as shown in fig. 3, the back surface of the first chip 110 is fixed in the groove on the dummy wafer 120 by the patch adhesive 121, wherein the surface of the first chip 110 is flush with the surface of the dummy wafer 120, that is, the front surface of the first chip 110 is flush with the surface of the dummy wafer 120, and the surface of the first chip 110 is flush with the surface of the dummy wafer 120, so that the thermal compression bonding with the plurality of second chips 140 can be better performed. The chip functional area of the first chip 110 can be expanded through the dummy wafer 120, the front surface of the first chip 110 and the front surface of the dummy wafer 120 are provided with a plurality of conductive through holes 130, and the plurality of conductive through holes 130 can be distributed at equal intervals, wherein the conductive through holes can be through silicon vias. And the vertical electrical interconnection of the silicon through holes is realized by adopting a silicon through hole technology, so that the packaging height is reduced.
And S120, carrying out hot-press bonding on the plurality of second chips, the dummy chip and the first chip respectively, wherein orthographic projections of the plurality of second chips on the dummy chip are located on the inner side of the dummy chip.
Specifically, as shown in fig. 3, 4 and 5, the surfaces of the first chip 110 and the dummy sheet 120 facing the plurality of second chips 140 are provided with a first passivation layer 111 and metal pads 112, wherein each metal pad 112 on the first chip 110 corresponds to each conductive via 130 of the first chip 110. As shown in fig. 6, a surface of the plurality of second chips 140 facing the first chip 110 is provided with a second passivation layer 141 and a plurality of conductive bumps 142.
It should be noted that the number of the second chips 140 may be 2, 3, 4, etc., and the types of the second chips 140 may be the same or different. The number and type of the second chips 140 are not specifically required in this embodiment, and can be selected according to actual needs.
It should be further noted that, as shown in fig. 6, in the present embodiment, a plurality of conductive vias 130 are disposed at the plurality of second chips 140 corresponding to the central region of the dummy sheet 120, and no conductive via 130 is disposed at the plurality of second chips 140 corresponding to the edge region of the dummy sheet 120. Thus, the plurality of second chips 140 located in the edge region are electrically connected to the plurality of second chips 140 located in the central region through the metal pads 112 on the surface of the dummy sheet 120, and then signals of the plurality of second chips 140 and the first chip 110 are led out through the plurality of conductive vias 130 on the dummy sheet 120 and the first chip 110. Of course, the dummy wafer 120 may be provided with a plurality of conductive vias 130 corresponding to all of the plurality of second chips 140, the plurality of second chips 140 are electrically connected through the first metal pads 112 on the surface of the dummy wafer 120, and then signals of the plurality of second chips 140 and the first chip 110 are led out through the plurality of conductive vias 130 on the dummy wafer 120 and the first chip 110. A plurality of second chips 140 pass over the dummy sheet 120. That is, the dummy sheet 120 is provided with a plurality of conductive vias 130 corresponding to at least a portion of the plurality of second chips 140.
In the present embodiment, as shown in fig. 6, three second chips 140 connected in the lateral direction are included, each second chip 140 is located in the central region and each second chip 140 is located in the edge region, and the plurality of second chips are connected in the lateral direction, so that the package height is further reduced. Wherein the size of the second chip 140 located in the central region is larger than the size of the first chip 110 and the two second chips 140 located in the edge region. The dummy wafer 120 is provided with a conductive via 130 at a position corresponding to the second chip 140 in the central region, and the dummy wafer 120 is not provided with the conductive via 130 at two positions corresponding to the second chips 140 in the edge region.
Illustratively, before thermocompression bonding the plurality of second chips with the dummy chip and the first chip, respectively, the method further includes:
firstly, forming an adhesive glue on the surfaces of the dummy piece and the first chip, and filling part of the adhesive glue into a gap between the dummy piece and the first chip.
Specifically, as shown in fig. 4, an adhesive 122 is formed on the surfaces of the dummy sheet 120 and the first chip 110, and a part of the adhesive 122 is filled into the gap between the dummy sheet 120 and the first chip 110, so as to completely fix the first chip 110 in the groove of the dummy sheet 120.
And secondly, removing the adhesive glue on the surfaces of the dummy wafer and the first chip to expose the first passivation layer and the metal bonding pad of the dummy wafer and the first chip.
Specifically, as shown in fig. 5, the adhesive 122 on the surface of the first chip 110 may be subjected to surface grinding and polishing, and the adhesive 122 on the surfaces of the dummy wafer 120 and the first chip 110 is removed, as shown in fig. 5, to expose the first passivation layer 111 and the metal pad 112 on the dummy wafer 120 and the first chip 110. Other methods may be used to remove the adhesive 122, and the embodiment is not limited in particular.
Before thermocompression bonding the plurality of second chips to the dummy chip and the first chip, the method may further include:
and forming a non-conductive adhesive layer, wherein the non-conductive adhesive layer wraps the conductive bump.
Specifically, as shown in fig. 6, before the second chip 140 is thermally and pressure bonded to the dummy wafer 120 and the first chip 110, that is, after the adhesive 122 on the surfaces of the dummy wafer 120 and the first chip 110 is removed in the above steps to expose the first passivation layer 111 and the metal pad 112 of the dummy wafer 120 and the first chip 110, the non-conductive adhesive layers 150, 150 are formed to wrap the conductive bump 142, so as to protect the conductive bump 142.
It should be noted that there are two using methods of the non-conductive adhesive at present, one using method is that the non-conductive adhesive is made into a thin film structure to form the non-conductive adhesive layer 150, which is coated on the surface of the second chip 140 facing the first chip 110 in advance to cover the conductive bump 142, and then the metal pad 112 and the conductive bump 142 in the first chip 110 and the second chip 140 are soldered; alternatively, a non-conductive adhesive is applied to the surface of the first chip 110 facing the second chip 140 to form the non-conductive adhesive layer 150, and then the second chip 140 is bonded to the first chip 110 through the non-conductive adhesive layer 150.
Since the non-conductive adhesive is coated before the conductive bump 142 is soldered, the non-conductive adhesive on the soldering surface needs to be completely removed from the soldering interface during soldering, which has an extremely high requirement for the characteristics of the non-conductive adhesive material. The non-conductive adhesive layer formed by the non-conductive adhesive ensures the welding effect of the metal pad 112 and the conductive bump 142.
The thermal compression bonding of the plurality of second chips with the dummy chip and the first chip respectively includes:
and carrying out thermocompression bonding on the metal bonding pad and the plurality of conductive bumps.
Specifically, as shown in fig. 6, the bonding connection is achieved by soldering the conductive bump 142 to the metal pad 112 by the action of heat and pressure. In the present embodiment, the material of the conductive bump 142 is a copper-tin conductive bump, the material of the metal pad 112 is metal copper, and the materials of the conductive bump 142 and the metal pad 112 are not particularly limited in this embodiment.
And the second chips are respectively subjected to wafer-level hot-pressing bonding with the first chip and the dummy wafer, so that the packaging height is further reduced, and high-density interconnection is realized.
As shown in fig. 6, the orthographic projections of the plurality of second chips 140 on the dummy sheet 120 fall on the inner side of the dummy sheet 120, that is, the total size of the plurality of second chips 140 is smaller than the size of the dummy sheet 120.
S130, forming a first plastic package layer, wherein the first plastic package layer wraps the plurality of second chips.
Specifically, as shown in fig. 7, since the size of the plurality of second chips 140 is smaller than that of the dummy wafer 120, a first molding layer 160 may be formed on the plurality of second chips 140, and the first molding layer 160 protects the plurality of second chips 140, so that the size of the first molding layer 160 covering the plurality of second chips 140 may be the same as that of the dummy wafer 120, that is, the first molding layer 160 expands the second chips. The plastic packaging method may be vacuum lamination of the film layer or a conventional plastic packaging process, and this embodiment is not particularly limited.
S140, forming a second plastic package layer, wherein the second plastic package layer wraps the first chip, the dummy wafer and the first plastic package layer.
Firstly, thinning the surfaces of the bonded first chip and the dummy wafer, which are deviated from the plurality of second chips, and exposing the conductive through holes of the first chip and the dummy wafer.
Specifically, as shown in fig. 8, the back surfaces of the bonded first chip 110 and dummy wafer 120 may be thinned through a grinding and polishing process, and then the conductive through holes 130, i.e., through silicon vias, of the first chip 110 and dummy wafer 120 are exposed through an etching process. Wherein, the residual thickness of the first chip 110 and the dummy sheet 120 after thinning is less than 40 um. By thinning the back surfaces of the first chip 110 and the dummy wafer 120, the conductive through holes 130 are exposed to realize electrical connection, and the package height is further reduced. In the present embodiment, the thickness of the first molding compound 160 meets the relevant requirements, so the thinning process is not needed, and if the thicknesses of the first molding compound 160 and the second chip 140 are very thick, the thinning process is needed for the first molding compound 160.
Secondly, fixing the thinned surfaces of the first chip and the dummy wafer deviating from the plurality of second chips on a temporary carrier plate, and then forming the second plastic packaging layer.
Specifically, the above packaging steps are to package the plurality of first chips 110, the plurality of dummy wafers 120, and the plurality of second chips 140 at the same time, and after the first chips 110 and the dummy wafers 120 are thinned, the thinned plurality of chip assemblies need to be cut to form a plurality of independent chip assemblies as shown in fig. 8. The following encapsulation steps are then performed.
As shown in fig. 9, the surfaces of the thinned first chip 110 and dummy wafer 120, which are away from the plurality of second chips 140, are fixed on the temporary carrier plate 161 by bonding glue, that is, the back surfaces of the first chip 110 and dummy wafer 120 are used as contact surfaces, and are attached to the temporary carrier plate 161 with the temporary bonding glue one by one according to the final package size, and then package is performed, so as to form a second plastic package layer 170 shown in fig. 10, where the second plastic package layer 170 wraps the first chip 110, dummy wafer 120 and first plastic package layer 160. The plastic packaging method may be vacuum lamination of the film layer or a conventional plastic packaging process, and this embodiment is not particularly limited.
S150, forming a rewiring layer on the dummy chip and the surface of the first chip, which is far away from the plurality of second chips, wherein the rewiring layer is electrically connected with the first chip through the conductive through hole.
Illustratively, the forming a redistribution layer on the dummy chip and the surface of the first chip facing away from the plurality of second chips includes:
first, the first chip and the dummy wafer are separated from the temporary carrier board.
Specifically, as shown in fig. 11, the first chip 110 and the dummy wafer 120 are separated from the temporary carrier board 161, that is, the temporary carrier board 161 is removed. The separation method can adopt methods such as thermal separation, laser separation, ultraviolet light separation, mechanical separation and the like, which are all common temporary bonding separation methods at present, the embodiment of the separation method is not particularly limited, and the separation method can be selected according to actual needs.
And secondly, forming dielectric layers on the surfaces of the second plastic packaging layer, the dummy chip and the first chip, which are far away from the plurality of second chips.
Specifically, as shown in fig. 12, a dielectric layer 180 is coated on the surfaces of the second molding layer 170, the dummy wafer 120 and the first chip 110 facing away from the second chip 140. That is, the dielectric layer 180 is formed on the back surfaces of the second molding layer 170, the thinned first chip 110 and the dummy wafer 120. The material of the dielectric layer 180 may be Polyimide (PI), Polybenzoxazole (PBO), etc., and the coating method is usually wafer spin coating, which is not limited in this embodiment.
And patterning the dielectric layer, and forming a rewiring layer on the patterned dielectric layer.
Specifically, as shown in fig. 12, the dielectric layer 180 is patterned by a photolithography process, and a redistribution layer 190 is formed on the patterned dielectric layer 180. The redistribution layer 190 is electrically connected to the first chip 110 through the conductive via 130. The method for forming the redistribution layer 190 may be sputtering, electroplating, etc., and this embodiment is not particularly limited. The redistribution layer 190 may be made of titanium and copper, or may be made of other metal materials, which is not specifically limited in this embodiment.
And finally, patterning the redistribution layer, and forming solder balls on the patterned redistribution layer.
Specifically, as shown in fig. 12, the redistribution layer 190 is patterned by a photolithography process, and a plurality of solder balls 200 are formed by ball-mounting on the patterned redistribution layer 190 and electrically connected to the outside through solder balls 210.
Package height is further reduced by replacing conventional substrate interconnects with redistribution layers.
According to the packaging method and the packaging device of the fan-out stacked chip, provided by the invention, the first chip and the second chips are respectively expanded by the dummy chip and the first plastic package layer through a wafer expansion technology, multi-chip signals are bridged, and the second chips are respectively thermally and thermally bonded with the dummy chip and the first chip, so that the high-density interconnection is realized and the production efficiency is improved. The dummy wafer is used for transversely bridging the second chips, so that the packaging height is further reduced; the dummy chip and the first chip are provided with the plurality of conductive through holes, the rewiring layer is formed on the surfaces of the dummy chip and the first chip, which are away from the second chip, and the conventional substrate interconnection is replaced by the conductive through hole technology and the fan-out rewiring technology, so that the packaging size is reduced, and the ultrathin multilayer high-density stacked packaging is realized; and direct wafer hot-press bonding is adopted among the second chips, the dummy chips and the first chip, so that the packaging height is further reduced. The packaging method provided by the invention realizes high density and ultra-thinness of the fan-out type stacked chip.
As shown in fig. 12, another aspect of the present invention provides a fan-out stacked chip package structure 100, which includes a first chip 110, a dummy chip 120, a second chip 140, a thermocompression bonding structure (not shown), a first molding compound layer 160, a second molding compound layer 170, and a redistribution layer 180.
The dummy sheet 120 is provided with a slot body, the slot body is provided with a first chip 110, the first chip 110 and the dummy sheet 120 are both provided with a plurality of conductive through holes 130, and the conductive through holes 130 may be through silicon holes. The plurality of conductive vias 130 may be distributed at equal intervals, wherein the conductive vias may be through silicon vias. And the vertical electrical interconnection of the silicon through holes is realized by adopting a silicon through hole technology, so that the packaging height is reduced.
The plurality of second chips 140 are disposed on the first chip 110 and the dummy wafer 120, and are respectively connected with the dummy wafer 120 and the first chip 110 by thermocompression bonding through a thermocompression bonding structure, wherein orthographic projections of the plurality of second chips 140 on the dummy wafer 120 fall on the inner side of the dummy wafer 120. That is, the overall size of the plurality of second chips 140 is smaller than that of the dummy sheet 120. The dummy wafer is adopted to expand the functional area of the first chip, so that the production efficiency can be improved.
The first molding compound layer 160 wraps the plurality of second chips 140, and protects the plurality of second chips 140. Thus, the size of the first molding layer 160 covering the plurality of second chips 140 can be the same as that of the dummy sheet 120, that is, the first molding layer 160 expands the second chips.
The second plastic package layer 170 wraps the first chip 110, the dummy wafer 120 and the first plastic package layer 160, and protects the first chip 110, the dummy wafer 120 and the first plastic package layer 160.
The redistribution layer 200 is disposed on the dummy chip 120 and the surface of the first chip 110 away from the plurality of second chips 140, and the redistribution layer 200 is electrically connected to the first chip 110 through the conductive via 130.
Illustratively, as shown in fig. 12, the surfaces of the first chip 110 and the dummy wafer 120 facing the second chip 140 are provided with a first passivation layer 121 and a metal pad 112, and the surface of the second chip 140 facing the first chip 110 is provided with a second passivation layer 141 and a conductive bump 142. The thermocompression bonding structure includes a metal pad 122 and a conductive bump 142, wherein the metal pad 112 is thermocompression bonded to the conductive bump 142. That is, the bonding connection is achieved by soldering the conductive bump 142 to the metal pad 112 by heat and pressure.
Illustratively, as shown in fig. 12, the package structure 100 further includes a non-conductive adhesive layer 150, and the non-conductive adhesive layer 150 wraps the conductive bump 142 to protect the conductive bump 142.
Exemplarily, as shown in fig. 12, the package structure 100 further includes a dielectric layer 180 and solder balls 200, the dielectric layer 170 is disposed on the surfaces of the second molding compound layer 160, the dummy wafer 120 and the first chip 110 facing away from the second chip 140, and the redistribution layer 190 is disposed on the dielectric layer 180; solder balls 200 are disposed on the redistribution layer 190, and the solder balls 200 are electrically connected to the outside.
It should be noted that the number of the second chips 140 may be 2, 3, 4, and so on, and the types of the second chips 140 may be the same or different. The number and type of the second chips 140 are not specifically required in this embodiment, and can be selected according to actual needs.
Illustratively, the dummy wafer 120 is provided with a plurality of conductive vias 130 corresponding to at least a portion of the plurality of second chips 140. That is, the dummy chip 120 may be provided with the conductive vias 130 corresponding to all of the plurality of second chips 140, that is, all of the second chips 140 are connected to the conductive vias 130, and some of the second chips 140 may be connected to the dummy chip 120 and the conductive vias 130 on the first chip 140. Further preferably, in this embodiment, the dummy sheet 120 is provided with a plurality of conductive through holes 130 corresponding to the plurality of second chips 140 in the central region, and the dummy sheet 120 is not provided with the conductive through holes 130 corresponding to the plurality of second chips 140 in the edge region. Thus, the plurality of second chips 140 located in the edge region are electrically connected to the plurality of second chips 140 located in the central region through the first metal pads 112 on the surface of the dummy sheet 120, and then signals of the plurality of second chips 140 and the first chip 110 are led out through the plurality of conductive vias 130 on the dummy sheet 120 and the first chip 110.
In the present embodiment, as shown in fig. 12, three second chips 140 connected laterally are included, each second chip 140 is located in the central region and each second chip 140 is located in the edge region, and the plurality of second chips are connected laterally, so that the package height is further reduced. Wherein the size of the second chip 140 located in the central region is larger than the size of the first chip 110 and the two second chips 140 located in the edge region. The dummy wafer 120 is provided with a conductive via 130 at a position corresponding to the second chip 140 in the central region, and the dummy wafer 120 is not provided with the conductive via 130 at two positions corresponding to the second chips 140 in the edge region.
According to the packaging structure of the fan-out stacked chip, the first chip and the second chips are respectively subjected to wafer expansion through the dummy chip and the first plastic package layer, and the second chips are respectively connected with the dummy chip and the first chip through hot-pressing bonding through the hot-pressing bonding structure, so that the high-density interconnection is realized and the production efficiency is improved; meanwhile, the first chip and the dummy wafer are provided with the conductive through holes, and the plurality of second chips are transversely connected, so that the packaging height is further reduced, and high-density and ultra-thin packaging is realized.
It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.

Claims (10)

1. A method of packaging fan-out stacked die, the method comprising:
fixing a first chip in a groove body on a dummy chip, wherein the first chip and the dummy chip are both provided with a plurality of conductive through holes;
respectively carrying out thermocompression bonding on a plurality of second chips and the dummy chip and the first chip, wherein orthographic projections of the plurality of second chips on the dummy chip fall on the inner side of the dummy chip;
forming a first plastic packaging layer, wherein the first plastic packaging layer wraps the plurality of second chips;
forming a second plastic packaging layer, wherein the second plastic packaging layer wraps the first chip, the dummy wafer and the first plastic packaging layer;
and forming a rewiring layer on the dummy chip and the surface of the first chip, which is far away from the plurality of second chips, wherein the rewiring layer is electrically connected with the first chip through the conductive through hole.
2. The method of claim 1, wherein surfaces of the first chip and the dummy wafer facing the plurality of second chips are provided with a first passivation layer and a metal pad, and surfaces of the plurality of second chips facing the first chip are provided with a second passivation layer and a plurality of conductive bumps;
the thermal compression bonding of the plurality of second chips with the dummy chip and the first chip respectively includes:
and carrying out thermocompression bonding on the metal bonding pad and the plurality of conductive bumps.
3. The method of claim 2, wherein prior to thermocompression bonding the second chip to the dummy chip and the first chip, respectively, the method further comprises:
and forming a non-conductive adhesive layer which wraps the plurality of conductive bumps.
4. The method of claim 3, wherein prior to thermocompression bonding the second chip to the dummy chip and the first chip, respectively, the method further comprises:
forming an adhesive glue on the surfaces of the dummy chip and the first chip, and filling part of the adhesive glue into a gap between the dummy chip and the first chip;
and removing the adhesive glue on the surfaces of the dummy wafer and the first chip to expose the first passivation layer and the metal bonding pad of the dummy wafer and the first chip.
5. The method of claim 4, wherein the forming the second molding layer comprises:
thinning the surfaces of the bonded first chip and the bonded dummy wafer, which are far away from the plurality of second chips, to expose the conductive through holes of the first chip and the dummy wafer;
and fixing the thinned surfaces of the first chip and the dummy chip departing from the plurality of second chips onto a temporary carrier plate, and then forming the second plastic packaging layer.
6. The method of claim 5, wherein forming a redistribution layer on the dummy chip and the surface of the first chip facing away from the plurality of second chips comprises:
separating the first chip and the dummy wafer from the temporary carrier plate;
forming a dielectric layer on the surfaces of the second plastic packaging layer, the dummy chip and the first chip, which are far away from the plurality of second chips;
patterning the dielectric layer, and forming a rewiring layer on the patterned dielectric layer;
and patterning the redistribution layer, and forming solder balls on the patterned redistribution layer.
7. A packaging structure of fan-out stacked chips is characterized by comprising a first chip, a dummy wafer, a plurality of second chips, a hot-press bonding structure, a first plastic packaging layer, a second plastic packaging layer and a rewiring layer;
the dummy sheet is provided with a groove body, the groove body is provided with the first chip, and the first chip and the dummy sheet are both provided with a plurality of conductive through holes;
the second chips are arranged on the first chip and the dummy chip and are respectively connected with the dummy chip and the first chip in a hot-press bonding mode through the hot-press bonding structure, wherein orthographic projections of the second chips on the dummy chip fall on the inner side of the dummy chip;
the first plastic packaging layer wraps the plurality of second chips;
the second plastic packaging layer wraps the first chip, the dummy sheet and the first plastic packaging layer;
the rewiring layer is arranged on the dummy chip and the surface of the first chip, which is far away from the plurality of second chips, and the rewiring layer is electrically connected with the first chip through the conductive through hole.
8. The package structure according to claim 7, wherein a first passivation layer and a metal pad are disposed on surfaces of the first chip and the dummy wafer facing the plurality of second chips, and a second passivation layer and a plurality of conductive bumps are disposed on surfaces of the plurality of second chips facing the first chip;
the thermocompression bonding structure comprises the metal pad and the plurality of conductive bumps, wherein the metal pad is connected with the plurality of conductive bumps in a thermocompression bonding manner.
9. The package structure of claim 8, wherein the dummy wafer is provided with the plurality of conductive vias corresponding to at least a portion of the plurality of second chips.
10. The package structure of claim 9, wherein the dummy wafer is provided with the plurality of conductive vias at the plurality of second chips corresponding to the central region.
CN202111493899.1A 2021-12-08 2021-12-08 Packaging method and packaging structure of fan-out type stacked chip Pending CN114171404A (en)

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CN202111493899.1A CN114171404A (en) 2021-12-08 2021-12-08 Packaging method and packaging structure of fan-out type stacked chip
PCT/CN2022/137246 WO2023104094A1 (en) 2021-12-08 2022-12-07 Fan-out packaging method and packaging structure of stacked chips thereof

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023104094A1 (en) * 2021-12-08 2023-06-15 Tongfu Microelectronics Co., Ltd. Fan-out packaging method and packaging structure of stacked chips thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023104094A1 (en) * 2021-12-08 2023-06-15 Tongfu Microelectronics Co., Ltd. Fan-out packaging method and packaging structure of stacked chips thereof

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