WO2020103743A1

WO2020103743A1 - Chip packaging structure

Info

Publication number: WO2020103743A1
Application number: PCT/CN2019/118159
Authority: WO
Inventors: 王之奇; 胡津津; 吴明轩
Original assignee: 苏州晶方半导体科技股份有限公司
Priority date: 2018-11-20
Filing date: 2019-11-13
Publication date: 2020-05-28
Also published as: WO2020103744A1; CN109524382A; CN109524382B

Abstract

Disclosed is a chip (22) packaging structure, the chip (22) is packaged by means of a packaging substrate (21) having a through hole (T). The chip (22) is fixed on a first surface of the packaging substrate (21) and covers the through hole (T); the chip (22) is electrically connected to electrical contact bulges (24) arranged on the first surface so as to realize electric connection with outside circuits. An adhesive layer (25) is provided on the surface of the chip (22) at the side away from the packaging substrate (21), and heat from the chip (22) can be conducted to the adhesive layer (25) for quicker dissipation, thereby improving the heat dissipation performance of the packaging structure.

Description

Chip packaging structure

This disclosure requires the priority of a Chinese patent application filed on November 20, 2018 in the China Patent Office with the application number 201811382449.3. The content of the above application is incorporated by reference in this disclosure.

Technical field

This application relates to the field of chip packaging technology, for example, to a chip packaging structure.

Background technique

With the continuous development of science and technology, more and more electronic devices are widely used in people's daily life and work, which brings great convenience to people's daily life and work, and becomes an indispensable important thing for people today. tool.

The main component of the electronic device to realize the preset function is the chip. With the continuous progress of integrated circuit technology, the integration of the chip is getting higher and higher, the function of the chip is getting stronger, and the size of the chip is getting smaller and smaller, so the chip needs Through packaging, a packaging structure is formed, so that the chip is electrically connected to an external circuit.

When the chip is packaged to form a package structure, the chip is generally electrically connected to the package substrate directly, and the chip is electrically connected to the external circuit through the package substrate. In the related art, the heat dissipation performance of the chip packaging structure is poor.

Summary of the invention

The present application provides a chip packaging structure, which can improve the heat dissipation performance of the packaging structure.

This application provides the following technical solutions:

A packaging structure of a chip, the packaging structure includes:

A packaging substrate including opposite first and second surfaces, a through hole penetrating the first surface and the second surface, the first surface is provided with an electrical contact protrusion, the electrical contact The protrusion is used for electrical connection with an external circuit board;

A chip fixed on the first surface, the chip covering the through hole, the chip is electrically connected to the electrical contact protrusion; covering a side surface of the chip facing away from the packaging substrate and the first An adhesive layer on the surface, the adhesive layer exposes the end of the electrical contact protrusion facing away from the packaging substrate, so that the end is electrically connected to the external circuit board; in the first direction, the electrical contact The height of the protrusion is greater than the height of the chip;

Wherein the first direction is directed from the second surface to the first surface.

BRIEF DESCRIPTION

Figure 1 is a schematic diagram of a conventional chip packaging structure;

2 is a schematic diagram of a chip packaging structure provided by an embodiment of the present application;

3 is a schematic diagram of another chip packaging structure provided by an embodiment of the present application;

4 is a schematic diagram of yet another chip packaging structure provided by an embodiment of the present application;

5 to 13 are schematic flowcharts of a chip packaging method provided by an embodiment of the present application.

detailed description

The technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Referring to FIG. 1, FIG. 1 is a schematic diagram of a package structure of a conventional chip. The package structure shown in FIG. 1 includes: a package substrate 11, a chip 12 and a cover 13. The package substrate 11 includes opposite first and second surfaces, and has a through hole 16 penetrating the first and second surfaces. The cover plate 13 is fixed on the second surface and covers the through hole 16, and the chip 12 is fixed on the first surface and covers the through hole 16. The first surface has solder bumps 14 and the chip 12 is electrically connected to the solder bumps 14. The solder bump 14 is used for electrical connection with an external circuit. An adhesive layer 15 is provided on the first surface, and the adhesive layer 15 surrounds the sidewall of the chip 12.

As can be seen from the package structure shown in FIG. 1, in order to facilitate the electrical connection between the solder bump 14 and an external circuit, with reference to the first surface of the packaging substrate 11, the height of the chip 12 is smaller than the height of the solder bump 14. Therefore, there are two main heat dissipation paths for the heat generated by the chip 12, one is through the back surface of the chip 12 to the air, this method directly dissipates heat through the back of the chip 12, because the chip 12 is generally a semiconductor material substrate, the thermal conductivity is poor, It is inconvenient for the heat to be quickly dissipated from the chip 12, and the other is to conduct heat to the solder bump 14 through the circuit, and dissipate heat through the solder bump 14, which dissipates heat through the metal circuit. Although the metal circuit has good thermal conductivity, the heat needs to pass through The area where the front surface of the chip 12 is electrically connected to the package substrate 11 is transferred to the solder bump 14 through the metal line. On the one hand, the area is small, and it is not convenient for the heat to be quickly radiated from the front surface of the chip 12, Longer, it is not convenient for rapid heat dissipation. It can be seen that the existing chip packaging structure has poor heat dissipation performance.

In order to solve the above problems, the technical solution of the present application provides a chip packaging structure and a packaging method, by providing an adhesive layer on the back of the chip, so that the heat of the chip can be transferred to the adhesive layer and then dissipated through the adhesive layer, so that the heat is quickly transferred Go out to avoid heat accumulation in the chip and improve heat dissipation performance.

In order to make the above objects, features and advantages of the present application more obvious and understandable, the present application will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Referring to FIG. 2, FIG. 2 is a schematic diagram of a chip packaging structure provided by an embodiment of the present application. The packaging structure includes: a packaging substrate 21, and the packaging substrate 21 includes opposite first surfaces and second surfaces, which extend through the A through hole T on the first surface and the second surface, the first surface is provided with an electrical contact protrusion 24 for electrically connecting with an external circuit board; fixed on the first surface Chip 22, the chip 22 covers the through hole T, the chip 22 is electrically connected to the electrical contact protrusion 24; covers the side surface of the chip 22 facing away from the packaging substrate 21 and the first An adhesive layer 25 on the surface, the adhesive layer 25 exposes the end of the electrical contact protrusion 24 facing away from the packaging substrate 21, so that the end is electrically connected to the external circuit board. The external circuit board is not shown in FIG. 2.

In the structure described in the embodiment of the present application, the chip 22 has opposite back and front sides, and the front side faces the first surface. By providing an adhesive layer 25 on the back of the chip 22, heat can be transferred from the back of the chip 22 to the adhesive layer 25, so that the heat is quickly conducted out of the chip 22, preventing heat from accumulating in the chip 22 and improving heat dissipation speed. Moreover, the gap between the side wall of the chip 22 and the electrical contact bump 24 is filled through the adhesive layer 25, so that heat is directly transmitted to the electrical contact bump 24 through the adhesive layer 25 through the side wall of the chip 22, the heat dissipation path is short, and passes through the entire chip The side wall of 22 conducts heat and the heat dissipation area is large, which can greatly improve the heat dissipation speed. At the same time, the adhesive layer 25 covers the chip 22 and covers the first surface. Compared with the back surface of the chip 22, the surface of the side of the back package substrate 21 of the adhesive layer 25 has a larger area, which can increase the heat dissipation speed. Therefore, the packaging structure described in the embodiments of the present application has better heat dissipation performance.

The adhesive layer 25 is made of thermally conductive adhesive, so that the heat of the chip 22 can be quickly transferred to the adhesive layer 25 through the back of the chip, and dissipated through the adhesive layer 25 to increase the speed of heat transfer out of the chip 22 and avoid heat accumulation in the chip 22 . The thermal conductivity of the adhesive layer 25 is greater than the thermal conductivity of the substrate of the chip 22. If the silicon substrate is used to prepare the chip 21, the thermal conductivity of the adhesive layer 25 is greater than that of the silicon substrate.

As shown in FIG. 2, in the first direction, the height of the electrical contact protrusion 24 is greater than the height of the chip 22; wherein, the first direction is directed from the second surface to the first surface. In other ways, in the first direction, the height of the electrical contact protrusion 24 may be the height of the chip 22, in which case the external circuit board needs to have a soldering protrusion matching the electrical contact protrusion 24 for The contact protrusion 24 is soldered and fixed, so that the package structure is electrically connected to the external circuit board.

As shown in FIG. 2, in the first direction, the height of the electrical contact protrusion 24 is greater than the maximum distance of the adhesive layer 25 from the surface of the packaging substrate 21 to the packaging substrate 21; wherein, the first A direction is directed from the second surface to the first surface. In this way, the package structure can be directly electrically connected to the external circuit board through the exposed end of the electrical contact protrusion 24. In other manners, the height of the electrical contact protrusion 24 may also be set to be less than the maximum distance from the surface of the adhesive layer 25 away from the surface of the packaging substrate 21 to the packaging substrate 21, at this time, in order to facilitate electrical connection with an external circuit board For connection, the adhesive layer 25 needs to be provided with an opening exposing the electrical contact protrusion 24, and the external circuit board needs to have a soldering protrusion matching the electrical contact protrusion 24 for welding and fixing with the electrical contact protrusion 24, so as to facilitate the packaging structure and The external circuit board is electrically connected.

The electrical contact protrusion 24 is soldered and fixed to the external circuit board, and the adhesive layer 25 on the surface of the chip 22 facing away from the packaging substrate 21 is in contact with and fixed to the external circuit board. In this way, when bound to the external circuit board, the heat of the adhesive layer 25 can be directly transmitted to the external circuit board, and the heat is radiated through the external circuit board. Compared with the way in which the adhesive layer 25 and the external circuit board have a gap, the heat dissipation rate is faster.

The adhesive layer 25 is a hot-melt adhesive. The adhesive layer 25 is heated and melted when the electrical contact protrusion 24 is welded to the external circuit board to fix the chip 22 and the external circuit board. The hot-melt adhesive with good thermal conductivity is used as the adhesive layer 25, which can be melted by heat when the electrical contact protrusion 24 is welded and fixed to the external circuit board. Due to the contact with the external circuit board due to gravity, on the one hand, it can improve the packaging structure and the external circuit. Fixing stability performance, on the other hand, can also make the adhesive layer 25 directly contact with the external circuit board, so that the heat causes the heat of the chip 22 to be transmitted to the external circuit board through the adhesive layer 25, and dissipates heat through the external circuit board to improve the heat dissipation performance.

In the embodiment of the present application, the packaging substrate 11 is any one of a PCB board, an organic substrate, and a glass substrate. The first surface has a pad electrically connected to the line, and the chip 22 fixed on the first surface is electrically connected to the pad. The pad is electrically connected to the electrical contact bump 24 through a metal line. The metal circuit may be provided on the first surface or inside the packaging substrate 21. The electrical contact protrusion 24 is a solder ball.

As shown in FIG. 2, the illustrated packaging structure further includes a light-transmitting cover plate 23 fixed on the second surface, and the light-transmitting cover plate 23 covers the through hole T. The light-transmitting cover plate 23 can be fixed to the packaging substrate 21 by adhesive. The 22-bit photosensitive chip of the chip may be, for example, an optical fingerprint chip.

Referring to FIG. 3, FIG. 3 is a schematic diagram of another chip packaging structure provided by an embodiment of the present application. Based on the manner shown in FIG. 2, in the manner shown in FIG. 3, after the chip 22 is fixed to the first surface, There is a gap 26 between the chip 22 and the first surface; the adhesive layer 25 also fills the gap 26. Generally, the chip 22 and the package substrate 21 are directly soldered and fixed, and the two are electrically connected by soldering and fixing. However, soldering is bound to make the chip 22 and the first surface of the package substrate 21 completely contactless. In this way, the gap can be filled through the adhesive layer 25. On the one hand, the fixing stability of the chip 22 and the first surface can be improved. On the other hand, the gap can be filled, the contact area of the chip 22 and the first surface can be increased, and the front surface of the chip 22 can be increased. The area of heat dissipation area improves heat dissipation performance.

Referring to FIG. 4, FIG. 4 is a schematic diagram of yet another chip packaging structure provided by an embodiment of the present application. Based on the manner shown in FIG. 3, in the manner shown in FIG. 4, the adhesive layer 25 further covers the through hole T Side wall 27 to reduce light reflection. For example, when the chip 22 is a photosensitive chip, the reflective layer of the through-hole T sidewall 27 can be reduced by an adhesive layer to avoid the influence of the reflected light of the through-hole T sidewall 27 on the detection result of the chip 22 and improve the detection accuracy of the chip 22.

It can be known from the above description that, in the packaging structure described in the embodiments of the present application, the packaging structure is simple and the manufacturing cost is low. Moreover, the heat dissipation performance of the packaging structure can be improved by the adhesive layer 25 provided on the back of the chip 22.

Based on the above packaging structure embodiment, another embodiment of the present application also provides a packaging method. The packaging method is shown in FIG. 5 to FIG. 11, and FIG. 5 to FIG. 11 is a chip package provided by an embodiment of the present application. Schematic diagram of the method. The packaging method includes:

Step S11: As shown in FIGS. 5 and 6, a substrate 20 is provided.

The base 20 includes a plurality of package substrates 21 arranged in an array, with a cutting channel 10 between adjacent package substrates 21, the package substrate 21 includes opposite first surfaces and second surfaces, and penetrates the first surface And the through hole T of the second surface, the first surface is provided with an electrical contact protrusion 24, and the electrical contact protrusion is used for electrical connection with an external circuit board. 5 is a plan view of the base 20 toward the first surface of each package substrate 21, and FIG. 6 is a cross-sectional view of FIG. 5 in the P-P 'direction.

The packaging substrate 21 is any one of a PCB board, an organic substrate, and a glass substrate. The electrical contact protrusion 24 is a solder ball.

A frame 30 of a predetermined height is fixed on the periphery of the base 20, the substrate 20 is placed horizontally, and the frame 30 is located above. By providing the frame 30 on the base 20, the adhesive layer 25 can be formed in subsequent steps . A carrier board 31 may be fixed on the second surface of the base 20.

Step S12: As shown in FIGS. 6 and 7, a chip 22 is fixed on the first surface, the chip 22 covers the through hole T, and the chip 22 is electrically connected to the electrical contact protrusion 24.

Step S13: As shown in FIG. 8, an adhesive layer 25 is formed on the surface of the substrate 20 on which the chip 22 is fixed.

The adhesive layer 25 covers a side surface of the chip 22 facing away from the packaging substrate 21 and the first surface, and the adhesive layer 25 exposes an end of the electrical contact protrusion 24 facing away from the packaging substrate 21, In order to facilitate the electrical connection between the end and the external circuit board.

In the first direction, the height of the electrical contact bump 24 is greater than the height of the chip 22, and the height of the electrical contact bump 24 is greater than the surface of the adhesive layer 25 facing away from the surface of the packaging substrate 21 to the package The maximum distance of the substrate 21; wherein the first direction is directed from the second surface to the first surface. The electrical contact protrusion 24 is soldered and fixed to the external circuit board, and the adhesive layer 25 on the surface of the chip 22 facing away from the packaging substrate 21 is in contact with and fixed to the external circuit board.

The adhesive layer 25 is a hot-melt adhesive. In this way, the adhesive layer 25 is heated and melted when the electrical contact protrusion 24 is welded to the external circuit board to fix the chip 22 and the external circuit board.

In this step, forming the glue layer 25 on the surface of the substrate 20 on which the chip 22 is fixed includes: injecting liquid glue into the frame 30, and after the liquid glue is cured, the glue layer 25 is formed. The side wall of the frame 30 may be provided with at least one opening through which liquid glue is injected into the frame 30. For example, an opening may be provided at each of the four top corners of the frame 30 for injecting liquid glue.

As shown in FIG. 9, before the next step of the cutting process, the packaging method further includes: after the liquid glue is cured, before the substrate 20 is divided, removing the frame 30.

As shown in FIG. 10, the packaging method further includes: after forming the adhesive layer 25 and before dividing the substrate 20, fixing the light-transmitting cover plate 23 on the second surface, the light-transmitting cover plate 23 covering the述通孔 T。 Said through hole T. If the carrier plate 31 is used, the carrier plate 31 can be removed, the substrate 20 can be placed horizontally, and the second surface of each package substrate 21 can be set upward, covering and fixing the transparent cover plate 23 on each through hole T. Each of the through holes T is provided with a transparent cover plate 23 respectively. The chip 22 is a photosensitive chip, and light signals can be collected through the through hole T and the transparent cover plate 23.

Step S14: As shown in FIG. 11, the substrate 20 is divided based on the cutting channel 10 to form a plurality of single-particle packaging structures.

The method shown in FIGS. 5-11 can be used to manufacture the package structure shown in FIG. 2. The method has simple process, low manufacturing cost, simple package structure and good heat dissipation performance.

If the package structure shown in FIG. 3 is manufactured, the difference from the above method is that, as shown in FIG. 12, after the chip 22 is fixed to the first surface, there is a gap 26 between the chip 22 and the first surface When the liquid glue is injected, the liquid glue fills the gap 26, so that after curing, the glue layer 25 also fills the gap 26. The size parameter of the gap can be adjusted by setting the bonding pad on the front surface of the chip 22 and the pad bonding the first surface with the bonding pad, so that the glue can completely fill the gap.

If only the packaging structure shown in FIG. 4 is made, it is different from the above method in that, when the liquid glue is injected, the liquid glue covers the side wall 27 of the through hole T through the gap 26, so that after curing, The adhesive layer 25 also covers the sidewall 27 of the through hole T to reduce light reflection.

The packaging method described in the embodiment of the present application can produce the packaging structure described in the above embodiments. The process is simple, the manufacturing cost is low, the manufactured packaging structure is simple, and the heat dissipation performance is good.

In the packaging structure and packaging method of a chip provided by the technical solution of the present invention, the chip is packaged through a packaging substrate having through holes. The package substrate has a through hole, fixes the chip to the first surface of the repackage substrate, and covers the through hole, the chip is electrically connected to the electrical contact protrusions provided on the first surface, so as to facilitate electrical connection with an external circuit connection. An adhesive layer is provided on a surface of the chip facing away from the packaging substrate, and the heat of the chip can be conducted to the adhesive layer, which accelerates the heat dissipation of the chip and improves the heat dissipation performance of the packaging structure.

The embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments may refer to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description in the method part.

It should also be noted that in this article, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these entities or operations There is any such actual relationship or order. Moreover, the terms "including", "comprising" or any other variant thereof are intended to cover non-exclusive inclusions, such that an article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, Or it also includes elements inherent to such articles or equipment. Without more restrictions, the element defined by the sentence "include one ..." does not exclude that there are other identical elements in the article or device that includes the above elements.

Claims

A chip packaging structure, including:

A packaging substrate including opposite first and second surfaces, a through hole penetrating the first surface and the second surface, the first surface is provided with an electrical contact protrusion, the electrical contact The protrusion is used for electrical connection with an external circuit board;

A chip fixed on the first surface, the chip covering the through hole, the chip is electrically connected to the electrical contact protrusion; covering a side surface of the chip facing away from the packaging substrate and the first An adhesive layer on the surface, the adhesive layer exposing the end of the electrical contact protrusion facing away from the packaging substrate, so that the end is electrically connected to the external circuit board;

In the first direction, the height of the electrical contact protrusion is greater than the height of the chip;

Wherein the first direction is directed from the second surface to the first surface.
The packaging structure of a chip according to claim 1, wherein in the first direction, the height of the electrical contact protrusion is greater than the maximum distance from the surface of the adhesive layer away from the surface of the packaging substrate to the packaging substrate;

Wherein the first direction is directed from the second surface to the first surface.
The packaging structure of a chip according to claim 1, wherein the electrical contact protrusion is soldered and fixed to the external circuit board, and the adhesive layer and the external circuit of the surface of the chip facing away from the side of the packaging substrate Board contact fixed.
The chip packaging structure according to claim 3, wherein the adhesive layer is a hot-melt adhesive, and the adhesive layer is heated and melted when the electrical contact protrusion is soldered and fixed to the external circuit board to fix the Chip and the external circuit board.
The packaging structure of a chip according to claim 1, wherein after the chip is fixed to the first surface, there is a gap between the chip and the first surface;

The glue layer also fills the gap.
The packaging structure of a chip according to claim 5, wherein the adhesive layer further covers the sidewall of the through hole to reduce light reflection.
The packaging structure of a chip according to claim 1, wherein the packaging substrate is any one of a PCB board, an organic substrate, and a glass substrate.
The packaging structure of a chip according to claim 1, further comprising: a light-transmitting cover plate fixed on the second surface, the light-transmitting cover plate covering the through hole.
The chip packaging structure according to claim 1, wherein the electrical contact protrusion is a solder ball.
The packaging structure of a chip according to claim 1, wherein the chip is a photosensitive chip.