TW201642437A - Stacked chip on film package structure and manufacturing method thereof - Google Patents

Abstract

A stacked chip on film (COF) package structure includes a first flexible substrate, a second flexible substrate, a first lead layer, a second lead layer, a first chip, a second chip, and an adhesive layer. The first lead layer and the first chip, and the second lead layer and the second chip are configured on a first effective surface of the first flexible substrate and a second effective surface of the second flexible substrate respectively. The first flexible substrate includes a first back surface opposite to the first effective surface, and the second flexible substrate includes a second back surface opposite to the second effective surface. The first back surface and the second back surface face each other and are connected to each other by the adhesive layer. The adhesive layer includes a plurality of electromagnetic shielding particles.

Description

Film flip chip package stack structure and manufacturing method thereof

The invention relates to a film flip chip package stack structure and a manufacturing method thereof. In particular, the present invention relates to a film flip chip package stack structure which can save space and avoid electromagnetic interference, and a manufacturing method thereof.

The chip packaging process is used to protect the wafer from external physical or chemical fluctuations and to provide wafer insulation protection to protect the wiring from external interference or mutual interference. In the field of driver ICs, especially for liquid crystal display (LCD) applications, tape carrier (TCP), chip on film (COF), and glass are often used. The driver IC is packaged in three package methods, such as Chip On Glass. Based on cost considerations, pitch, substrate flexibility and other factors, the film flip chip package has almost replaced the tape carrier package and has become the mainstream trend.

As today's electronic products demand higher and higher reaction speeds and more and more complex functions, and the appearance part is constantly demanding light and thin, the drive circuit also tends to a high integrated density, that is, in a certain space Place more circuits or chips than before. The increasingly dense integrated circuit design increases the number of wafers in a limited space and the distance between wafers becomes closer and closer, resulting in more and more serious electromagnetic interference.

Based on the above problems, it is necessary to develop a film flip chip package stack structure capable of incorporating more integrated circuits in a certain space and blocking electromagnetic interference phenomenon and a manufacturing method thereof.

One aspect of the present invention is to provide a thin film flip chip package stack structure. According to an embodiment of the present invention, a thin film flip chip package stack structure includes a first flexible substrate, a second flexible substrate, a first wire layer, a second wire layer, a first wafer, a second wafer, and an adhesive Floor. In this embodiment, the first flexible substrate has a first first functional surface and a first back surface, and the second flexible substrate has a second second functional surface and a second back surface. The first wire layer is disposed on the first functional surface, and the second wire layer is disposed on the second functional surface. The first wafer is disposed on the first functional surface and electrically connected to the first wire layer, and the second wafer is disposed on the second functional surface and connected to the second wire layer. The first back surface of the first flexible substrate faces the second back surface of the second flexible substrate, and the first back surface and the second back surface are connected to each other by an adhesive layer. The adhesive layer contains a plurality of electromagnetic shielding particles to help block electromagnetic interference between the first wafer and the second wafer.

Another aspect of the present invention is to provide a method of fabricating a thin film flip chip package stack structure. According to an embodiment of the present invention, a method for fabricating a thin film flip chip package structure of the present invention comprises the steps of: providing a first thin film flip chip package, the first film flip chip package comprising a first surface having a first back surface a flexible substrate; a second film flip chip package, the second film flip chip package comprising a second flexible substrate having a second back surface; and an adhesive layer disposed on the first back surface of the first flexible substrate; Deploying a plurality of electromagnetic shielding particles on the adhesive layer; and disposing the first thin film flip chip package and the second thin film flip chip package The pressing is performed in a back-to-back manner such that the adhesive layer connects the first back surface and the second back surface.

The film flip chip package stack structure produced by the method of the embodiment has an adhesive layer containing electromagnetic shielding particles, and the adhesive layer can assist between the first film flip chip package and the second film flip chip package Electromagnetic interference.

The advantages and spirit of the present invention will be further understood from the following detailed description of the invention.

1‧‧‧ Film flip chip package stack structure

10‧‧‧First flexible substrate

20‧‧‧Second flexible substrate

12‧‧‧First wire layer

22‧‧‧Second wire layer

14‧‧‧First chip

24‧‧‧second chip

16‧‧‧First solder mask

26‧‧‧Second solder mask

18‧‧‧First encapsulant

28‧‧‧Second encapsulant

100‧‧‧ first function surface

102‧‧‧ first back

200‧‧‧second function surface

202‧‧‧ second back

30‧‧‧Adhesive layer

32‧‧‧Electromagnetic shielding particles

1 is a schematic view showing a stacked structure of a film flip chip package according to an embodiment of the present invention.

2A to 2F are structural diagrams showing the steps of a method for fabricating a stacked silicon wafer package according to an embodiment of the present invention.

FIG. 3A to FIG. 3G are structural diagrams showing steps of a method for fabricating a film flip chip package stack according to another embodiment of the present invention.

Referring to FIG. 1, FIG. 1 is a schematic diagram showing a film flip chip package stack structure 1 according to an embodiment of the present invention. As shown in FIG. 1 , the film flip chip package stack structure 1 includes a first flexible substrate 10 , a second flexible substrate 20 , a first wire layer 12 , a second wire layer 22 , a first wafer 14 , and a second wafer . 24 and the adhesive layer 30, the above elements are stacked on each other to form a thin film flip chip package stack structure 1.

In the embodiment, the first flexible substrate 10 has a first functional surface 100 and a first back surface 102 opposite to the first functional surface 100. Similarly, the second flexible substrate 20 also has an opposite second. Functional surface 200 and second back surface 202. The first of the flexible substrate 10 A functional surface 100 and a second functional surface 200 of the flexible substrate 20 can be used to provide a functional structural layer such as a wafer or a wiring layer.

As described above, the first wire layer 12 is disposed on the first functional surface 100 of the first flexible substrate 10, and the second wire layer 22 is disposed on the second functional surface 200 of the second flexible substrate 20. . The first wafer 14 is disposed on the first functional surface 100 and electrically connected to the first wire layer 12 . In more detail, the first wafer 14 is disposed in the pre-planned wafer setting area of the first functional surface 100 and can be The bumps are electrically connected to the first wire layer 12. Similarly, the second wafer 24 is disposed in the pre-planned wafer setting area of the second functional surface 200, and is electrically connected to the second wiring layer 22 by bumps. The first wire layer 12 and the second wire layer 22 respectively extend from the wafer setting area to the outer edges of the first functional surface 100 and the second functional surface 200, so that the first wafer 14 and the second wafer 24 can respectively pass through the first A wire layer 12 and a second wire layer 22 are electrically connected to an external circuit.

In addition to the above stacked layers, a first solder resist layer 16 and a second solder resist layer 26, a first solder resist layer 16 and a second solder resist layer are respectively disposed on the first wiring layer 12 and the second wiring layer 22. The first wire layer 12 and the second wire layer 22 are respectively covered to provide a protective effect on the first wire layer 12 and the second wire layer 22, and the first solder resist layer 16 and the second solder resist layer 26 respectively expose a portion. The first wire layer 12 and the second wire layer 22 are electrically connected to the wire layer and the external circuit. In addition, a space between the first wafer 14 and the first functional surface 100 and between the second wafer 24 and the second function 200 is further filled with a first encapsulant 18 and a second encapsulant 28, respectively, to the wafer and Electrical contacts (ie, bumps) of the wire layer provide protection.

The first back surface 102 of the first flexible substrate 10 and the second flexible substrate 20 The second back faces 202 face each other and are joined by an adhesive layer 30 therebetween. The adhesive layer 30 internally includes a plurality of electromagnetic shielding particles 32, which can electromagnetically shield the first wafer 14 and the second wafer 24 stacked on top of each other to assist the film flip chip package structure 1 to block electromagnetic interference. In practice, the electromagnetic shielding particles 32 may be selected from metal particles or any other particle capable of producing an electromagnetic shielding effect, and the metal particles may include silver, iron, copper, copper/nickel, copper/silver, gold, aluminum, nickel, brass. Other types of particles may include ferrite, graphite, carbon black, carbon nanotubes, carbon spheres, carbon fibers, nickel-plated graphite, nickel-plated carbon fibers, and copper/nickel carbon fibers.

As shown in FIG. 1, the electromagnetic shielding particles 32 of the film flip-chip package stack structure 1 of the present embodiment can be closely distributed in the adhesive layer 30 to form an electromagnetic shielding film, and the electromagnetic shielding film can be located near the adhesive layer 30. One side of the second back surface 202. The closer the density of the electromagnetic shielding particles 32 in the adhesive layer 30 is to the first back surface 102, the lower. The electromagnetic shielding film can effectively block electromagnetic interference between the first wafer 14 and the second wafer 24.

As described above, the film flip-chip package stack structure of the present invention is a pattern in which two thin film flip chip packages are stacked back-to-back, which can be used to connect two thin film flip chip packages in addition to improving electrical contacts and saving space. The body of the adhesive layer also contains electromagnetic shielding particles, which can block the electromagnetic interference between the two film flip-chip packages, so it conforms to the high bulk density trend of the wafer in the LCD driver IC and avoids the electromagnetic interference disadvantage.

Referring to FIG. 2A to FIG. 2F, FIG. 2A to FIG. 2F are schematic structural diagrams showing steps of a manufacturing method according to an embodiment of the present invention. The thin film flip chip package stack structure 1 as shown in FIG. 1 can be fabricated by using the fabrication method of the embodiment, so the reference numerals of FIG. 2A to FIG. 2F are compared with the labels of the film flip chip package stack structure 1 of FIG. Standard Show.

The manufacturing method of the film flip chip package stack structure of the embodiment includes the following steps. First, as shown in FIG. 2A, a first thin film flip chip package including a first flexible substrate 10, a first wiring layer 12, and a first wafer 14 is provided, wherein the first wiring layer 12 and the first wafer 14 are Provided on the first functional surface 100 of the first flexible substrate 10; as shown in FIG. 2B, a second thin film on-chip including the second flexible substrate 20, the second conductive layer 22, and the second wafer 24 is provided. The package body, wherein the second wire layer 22 and the second wafer 24 are disposed on the second functional surface 200 of the second flexible substrate 20. The structures of the first thin film flip chip package and the second thin film flip chip package are substantially the same as those of the foregoing specific embodiments, and thus will not be described herein.

Next, as shown in FIG. 2C, an adhesive layer 30 is disposed on the first back surface 102 of the first flexible substrate 10. Specifically, the first thin film flip chip package can be flipped so that the first back surface 102 of the first flexible substrate 10 faces upward to facilitate the adhesive layer 30 on the first back surface 102. As shown in FIG. 2D, a plurality of electromagnetic shielding particles 32 are disposed on the adhesive layer 30, wherein the electromagnetic shielding particles 32 are disposed by spraying the electromagnetic shielding particles 32 onto the adhesive layer 30 by spraying. In addition, the adhesive layer 30 disposed on the first back surface 102 can be in a liquid state. Therefore, after the electromagnetic shielding particles 32 are disposed on the liquid adhesive layer 30, the surface of the liquid adhesive layer 30 can gradually penetrate into the interior. Since the adhesive layer 30 has been disposed on the first back surface 102, the electromagnetic shielding particles 32 will first contact the adhesive layer 30 away from the side of the first back surface 102 during spraying, so that the electromagnetic shielding particles 32 after spraying are in the adhesive layer 30. The concentration away from the side of the first back side 102 is higher, and the closer to the first back side 102, the lower the concentration.

Next, as shown in FIG. 2E, the first thin film flip chip package and the second thin film flip chip package are pressed back to back, and the adhesive layer 30 is connected to the first back surface 102 and the second surface. Back side 202. After being pressed, the electromagnetic shielding particles 32 are closely distributed on the side of the adhesive layer 30 away from the first back surface 102, that is, on the side close to the second back surface 202, thereby forming an electromagnetic shielding film. In this embodiment, the electromagnetic shielding particles 32 may be selected from the group consisting of silver, iron, copper, copper/nickel, copper/silver, gold, aluminum, nickel, brass, stainless steel, ferrite, graphite, carbon black, Electromagnetic shielding materials such as carbon nanotubes, carbon spheres, carbon fibers, nickel-plated graphite, nickel-plated carbon fibers or copper-plated/nickel carbon fibers.

Furthermore, the adhesive layer 30 is used to connect the first film flip chip package and the second film flip chip package, so that the liquid adhesive layer 30 has to be converted into a solid state through a curing process to have sufficient bonding force to be fixed. Two thin film flip chip packages. As shown in FIG. 2F, the liquid adhesive layer 30 is subjected to a curing process after pressing, so that the liquid adhesive layer 30 is transformed into a semi-solid state and further converted into a solid state.

The manufacturing method of the above specific embodiment is to cure the liquid adhesive layer 30 after the entire film flip-chip package stack structure is completed. However, for the sake of convenience of production, the liquid adhesive layer 30 may be semi-cured first, so that the adhesive layer 30 is maintained in a specific shape before the subsequent process. Please refer to FIG. 3A to FIG. 3G. FIG. 3A to FIG. 3G are structural diagrams showing steps of a method for fabricating a film flip chip package stack according to another embodiment of the present invention. The steps illustrated in FIG. 3A to FIG. 3D are the same as those in FIG. 2A to FIG. 2D, and are not described herein again. The difference between this embodiment and the previous embodiment is that after the plurality of electromagnetic shielding particles 32 are disposed on the liquid adhesive layer 30 as shown in FIG. 3D, the electromagnetic shielding particles 32 are included. The liquid adhesive layer 30 is subjected to a curing process to convert the liquid adhesive layer 30 from a liquid state to a semi-solid state, as shown in FIG. 3E. Then, the first thin film flip chip package and the second thin film flip chip package are pressed back to back. The electromagnetic shielding film 32 is tightly distributed in the semi-solid adhesive layer 30 by applying pressure to the semi-solid adhesive layer 30 to form an electromagnetic shielding film, as shown in FIG. Finally, the semi-solid adhesive layer 30 is subjected to a curing process to further convert from a semi-solid to a solid state, as shown in FIG. 3G. Thereby, the solid-state adhesive layer 30 as shown in FIG. 1 is connected to form the thin film flip-chip package stack 1 by connecting the first thin film flip chip package and the second thin film flip chip package, and the adhesive layer 30 is simultaneously formed. The electromagnetic shielding film formed by the electromagnetic shielding particles 32 provides a good electromagnetic shielding effect.

In summary, the film flip-chip package stack structure and the manufacturing method thereof of the embodiment can increase the number of wafers in the unit volume of the LCD driver IC, conform to the trend of the high-speed integrated circuit, and have a good electromagnetic shielding effect. It can effectively block the electromagnetic interference between the wafers.

The features and spirit of the present invention will be more apparent from the detailed description of the preferred embodiments. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed.

1‧‧‧ Film flip chip package stack structure

10‧‧‧First flexible substrate

20‧‧‧Second flexible substrate

12‧‧‧First wire layer

22‧‧‧Second wire layer

14‧‧‧First chip

24‧‧‧second chip

16‧‧‧First solder mask

26‧‧‧Second solder mask

100‧‧‧ first function surface

102‧‧‧ first back

200‧‧‧second function surface

202‧‧‧ second back

30‧‧‧Adhesive layer

Claims (14)

A film flip-chip package stack structure comprising: a first flexible substrate comprising a first functional surface and a first back surface; a second flexible substrate comprising a second functional surface and a second a second back surface, the second back surface faces the first back surface; a first wire layer disposed on the first functional surface; a second wire layer disposed on the second functional surface; a first wafer, The first functional surface is electrically connected to the first wire layer; a second wafer is disposed on the second functional surface and electrically connected to the second wire layer; and an adhesive layer connecting the first A back side and the second back side, the adhesive layer comprising a plurality of electromagnetic shielding particles therein. The film flip chip package stack structure according to claim 1, wherein the electromagnetic shielding particles are closely distributed in the adhesive layer to form an electromagnetic shielding film. The film flip chip package stack structure of claim 2, wherein the electromagnetic shielding film is located on a side of the adhesive layer adjacent to the second back surface. The film flip chip package structure according to claim 1, wherein the material of the electromagnetic shielding particles is metal. The film flip chip package stack structure according to claim 4, wherein the materials of the electromagnetic shielding particles are selected from the group consisting of silver, iron, copper, copper/nickel, copper/silver, gold, aluminum, nickel, brass. a group of stainless steel. The film flip chip package stack structure according to claim 1, wherein the material of the electromagnetic shielding particles is selected from the group consisting of ferrite, graphite, carbon black, carbon nanotubes, carbon spheres, A group of carbon fiber, nickel-plated graphite, nickel-plated carbon fiber, and copper/nickel carbon fiber. A method for fabricating a film flip chip package stack structure, comprising the steps of: providing a first film flip chip package, wherein the first film flip chip package comprises a first a flexible substrate, a first wiring layer and a first wafer, the first flexible substrate includes a first functional surface and a first back surface, the first wiring layer and the first wafer system And electrically connecting to the first functional surface; providing a second thin film flip chip package, the second thin film flip chip package comprising a second flexible substrate, a second wire layer and a second chip The second flexible substrate includes a second functional surface and a second back surface. The second conductive layer and the second semiconductor layer are disposed on the second functional surface and electrically connected to each other. a glue layer on the first back surface; a plurality of electromagnetic shielding particles disposed on the adhesive layer; and the first film flip chip package and the second film flip chip package are pressed back to back, so that the adhesive layer A glue layer connects the first back surface and the second back surface. The method for fabricating a film flip chip package stack structure according to claim 7 , further comprising the steps of: providing the liquid adhesive layer on the first back surface; and the first film flip chip package and Before the second film flip chip package is pressed back to back, the liquid adhesive layer is cured, so that the liquid adhesive layer is converted from a liquid state to a semi-solid state, and then the semi-solid layer is applied to the adhesive layer. Pressing, the electromagnetic shielding particles are closely distributed in the semi-solid layer of the adhesive to form an electromagnetic shielding film. The method for fabricating a film flip chip package stack structure according to claim 8 , further comprising the step of: after the first film flip chip package and the second film flip chip package are pressed back to back The semi-solid layer of the adhesive is subjected to a curing process to further convert the semi-solid layer of the adhesive into a solid state. The method for fabricating a film flip chip package stack structure according to claim 7 , further comprising the steps of: providing a liquid layer of the adhesive layer on the first back surface; After the first film flip chip package and the second film flip chip package are pressed back to back, the liquid adhesive layer is cured to convert the liquid adhesive layer from a liquid state to a semi-solid state. And further transformed into a solid state. The method for fabricating a film flip chip package stack structure according to claim 7, wherein the material of the electromagnetic shielding particles is metal. The method for fabricating a film flip chip package structure according to claim 11, wherein the materials of the electromagnetic shielding particles are selected from the group consisting of silver, iron, copper, copper/nickel, copper/silver, gold, aluminum, and nickel. , a group of brass and stainless steel. The method for fabricating a film flip chip package stack structure according to claim 7, wherein the material of the electromagnetic shielding particles is selected from the group consisting of ferrite, graphite, carbon black, carbon nanotubes, and nanometer. A group of carbon spheres, carbon fibers, nickel-plated graphite, nickel-plated carbon fibers, and copper/nickel carbon fibers. The method for fabricating a film flip chip package stack structure according to claim 7, wherein the method of arranging the electromagnetic shielding particles on the adhesive layer comprises spraying.