JP2003297874A - Connection structure and connection method for electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for connecting electronic components with each other having low stress and high reliability. <P>SOLUTION: In the connection structure of the electronic component composed by connecting an electrode provided on one electronic component and an electrode provided on the other electronic component via an Au bump, by a process of forming the Au bump on the electrode of the electronic component, pressurizing a supply body containing at least Sn, for which a metal layer of a melting point lower than the one of Au is formed on a surface, at the top of the Au bump, transferring a metal of the metal layer to the top of the Au bump and thus forming a thin film, and a process of pressurizing the electrode of the other electronic component to the top of the Au bump in a state that the thin film is formed and heating the electrode, the electrode of the electronic component and the electrode of the other electronic component are connected via the thin film and the Au bump. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting structure and a connecting method for electronic parts using a bump connecting technique.

[0002]

2. Description of the Related Art Conventionally, SIP (System In Package)
As an important technology for supporting the above, a flip chip bonding technology that enables high-density mounting of semiconductor chips and a bonding technology using bumps such as COC (Chip On Chip) for directly bonding the semiconductor chips are adopted. In particular, as a bump bonding technology, GGI (Gold-to-Gold Interconnec
A method using thermocompression bonding of Au (gold) or ultrasonic bonding called t) is being studied.

A conventional electronic component connection structure and connection method using GGI technology as bump bonding technology will be described below with reference to the drawings. FIG. 5 is a cross-sectional view showing a conventional connection structure and connection method for electronic components. In the conventional method for connecting electronic components, first, as shown in FIG. 5A, Au bumps 12 are formed on the electrode portions 11 of the first electronic component 1. At this time, it is desirable that the Au bump 12 has a stud bump shape. Next, as shown in FIG.
Similar to the first electronic component 1, the second electronic component 2 having the Au bump 22 formed on the electrode portion 21 is installed so that the Au bump 22 and the Au bump 12 face each other. Next, as shown in FIG. 5C, the Au bump 12 is pressed against the Au bump 22. Finally, Figure 5
As shown in (d), the first electronic component 1 and the second electronic component 2 are heated to bond the Au bumps 12 and the Au bumps 22, and the electrode portion 11 and the electrode portion 21, that is, the first electronic component 1 The connection between the electronic component 1 and the second electronic component 2 is completed. Here, the Au bump 22 does not have to be an essential requirement, and instead of the Au bump 22, the electrode portion 21 is made of Au.
It may be bonded to the bump 12. Further, the first electronic component 1 and the second electronic component 2 may be regarded as, for example, a semiconductor chip and a mounting substrate.

[Problems to be Solved by the Invention]

In the manufacturing process of this conventional connection structure and connection method for electronic parts, damage to the semiconductor element existing under the bump, that is, around the electrode part, has been a problem due to high pressure and ultrasonic stress. . Therefore, a bonding process using a so-called low melting point metal (alloy) such as Sn (tin) or solder has been studied as a technique for obtaining a metal bond with low stress without damaging a semiconductor chip. However, when solder is used, it is necessary to form a metal layer called UBM (Under Bump Metal) on the pad of the semiconductor chip, which imposes a heavy cost burden. Further, it is necessary to use a flux in order to remove the surface oxide film of the solder in the joining process, and there is a problem that the residue of this flux adversely affects the reliability. Furthermore, when Sn is used,
Due to problems such as abnormal precipitation of crystals called whiskers, diffusion of Sn and dissimilar metals, and oxidation, special consideration was required for the storage of the material.

A means for solving such a problem is disclosed in JP-A-11-154689. The disclosed technical contents are a step of pressing a supply body such as a solder foil onto an Au bump provided on one electronic component to transfer the Au bump, and heating the one electronic component to perform the soldering. Is melted and solidified to form solder bumps on the Au bumps, and one electronic component and another electronic component are heated and joined via the solder bumps. However, when this technique is used, in the step of melting and solidifying the solder in order to form the solder bumps on the Au bumps, the melting point of the solder is increased due to the rapid diffusion of Au into the solder, so There is a possibility that a problem may occur in that joining by fusion of solder with another electronic component becomes difficult.

The present invention has been made in view of the above problems in the prior art, and it is an object of the present invention to provide a connection structure and a connection method for electronic components which have low stress and high reliability.

[Means for Solving the Problems]

In the connection structure for an electronic component according to the first invention of the present application, which is provided to solve the above-mentioned problems, an electrode portion provided on one electronic component and an electrode portion provided on another electronic component are Au. In a connection structure of electronic components connected via bumps, an Au bump is formed on an electrode portion of the one electronic component, and a metal having a melting point lower than that of Au containing at least Sn at the top of the Au bump. Forming a thin film by pressing the supply member having a layer formed on the surface thereof, and transferring the metal of the metal layer to the top of the Au bump;
By a step of pressing the electrode portion of the other electronic component on the top of the Au bump in the state where the thin film is formed and heating,
It is characterized in that the electrode portion of one electronic component and the electrode portion of another electronic component are connected via the thin film and the Au bump.

With such a structure, it is possible to join electronic components with low stress. In addition, by performing the supply step immediately before the joining process, there are no restrictions on the storage conditions of the material such as prevention of whiskers and oxidation / diffusion, which were problems in the conventional joining using Sn, and the new surface of Sn can be joined. Can be used. That is, according to the present invention, the structure of Au bump / supplying body (Sn-containing metal) / electrode part (Au) is formed instead of melting the supplying body after the transfer process by pressing the supplying body to the top of the Au bump. In this state, heating and mutual diffusion are promoted to obtain a bond.

According to a second aspect of the invention, there is provided an electronic component connection structure according to the second aspect of the present invention, wherein the Au bump has a stud bump shape. Characterize.

According to a third aspect of the invention, there is provided an electronic component connection structure according to the third aspect of the present invention, wherein the Au bump is a plated bump. And

According to a fourth aspect of the invention, there is provided an electronic component connecting structure according to the first aspect of the invention, wherein the electronic component connecting structure is provided on the surface of the electrode part of the other electronic component. An Au layer is formed.

With this configuration, the Au bumps of the electrode portion of one electronic component and the electrode portions of the other electronic component are formed through the thin film (Sn-containing metal) formed by transferring the supply member. The Au layer is joined to the Au layer in good electrical and strength. The Au layer mentioned here may be an Au bump.

According to a fifth aspect of the invention, there is provided a connection structure for an electronic component according to the fifth aspect of the present invention, wherein the Au layer has a stud bump shape. Characterize.

With such a structure, the tip end portion having a sharp shape such as a stud bump shape causes a large deformation amount when the Au bump of one electronic component is pressed against the supply member, so that the supply member is formed. The Sn-containing metal of the above A
It can be transferred to u bump. That is, a good thin film can be obtained, and as a result, a good connection between one electronic component and another electronic component can be realized.

According to a sixth aspect of the present invention, there is provided an electronic component connection structure according to the sixth aspect, wherein the Au layer is a plated bump. And

An electronic component connection structure according to a seventh invention of the present application, which is provided for solving the above-mentioned problems, is the electronic component connection structure according to any one of claims 1 to 6, wherein: Is a metal plate having a Sn plating layer or a solder plating layer formed on its surface.

According to an eighth aspect of the invention, there is provided an electronic component connection structure according to the eighth aspect of the invention, wherein the supply member is the electronic component connection structure according to any one of claims 1 to 6. Is a solder foil or a metal thin film containing at least Sn.

An electronic component connection structure according to a ninth invention of the present application, which is provided for solving the above-mentioned problems, is the electronic component connection structure according to any one of claims 1 to 8. The electronic component and the other electronic component are semiconductor chips or wiring boards.

The electronic component connecting method according to the tenth invention of the present application, which is provided to solve the above-mentioned problems, is to form an Au bump on an electrode portion provided on one electronic component, and to form a top portion of the Au bump. , A film containing at least Sn and having at least the surface formed of a metal layer having a melting point lower than that of Au is pressed to transfer the metal of the metal layer to the top of the Au bump to form a thin film. A step of pressing an electrode portion provided on the other electronic component on the top of the Au bump in a state where the thin film is formed, and heating the one electronic component and the other electronic component; And Au
And a step of connecting the electrode portion of one electronic component and the electrode portion of another electronic component via the bump.

By adopting such a method, it is possible to join electronic components with low stress. In addition, by performing the supply step immediately before the bonding process, there is no limitation on the storage conditions of the material such as prevention of whiskers and oxidation / diffusion, which has been a problem in the conventional bonding using Sn.
The new surface of n can be used for joining. That is, the present invention does not melt the supply body after the transfer process by pressing the supply body against the Au bump tops, but
In the state where the structure of u bump / supplying body (Sn-containing metal) / electrode part (Au) is formed, heating and mutual diffusion are promoted to obtain a bond.

According to an eleventh aspect of the invention, there is provided an electronic component connecting method according to the eleventh aspect of the present invention, wherein the Au bump has a stud bump shape. Is characterized by.

According to a twelfth aspect of the invention, there is provided a method for connecting electronic components according to the twelfth aspect of the present invention, wherein the Au bumps are plated bumps. Characterize.

The electronic component connecting method according to the thirteenth invention of the present application, which is provided for solving the above-mentioned problems, is the electronic component connecting method according to claim 10, wherein the surface of the electrode portion of the other electronic component is Is characterized in that an Au layer is formed.

By adopting such a method, it is formed on the Au bump of the electrode portion of one electronic component and the electrode portion of another electronic component via the thin film (Sn-containing metal) formed by transferring the supply member. The Au layer and the Au layer are well joined in terms of electrical strength. The Au layer mentioned here may be an Au bump.

According to a fourteenth aspect of the invention, there is provided an electronic component connecting method according to the fourteenth aspect of the present invention, wherein the Au layer has a stud bump shape. Is characterized by.

By adopting such a method, it is possible to increase the amount of deformation when the Au bump of one electronic component is pressed against the supply body by the pointed end shape such as the stud bump shape. The Sn-containing metal of the body can be efficiently transferred to the Au bump. That is, a good thin film can be obtained, and as a result, a good connection between one electronic component and another electronic component can be realized.

According to a fifteenth aspect of the invention, there is provided an electronic component connecting method according to the thirteenth aspect, wherein the Au layer is a plated bump. Characterize.

An electronic component connecting method according to the sixteenth invention of the present application, which is provided for solving the above-mentioned problems, is the electronic component connecting method according to any one of claims 10 to 15. The body is a metal plate having an Sn plating layer or a solder plating layer formed on its surface.

An electronic component connecting method according to a seventeenth invention of the present application, which is provided for solving the above-mentioned problems, is the electronic component connecting method according to any one of claims 10 to 15. The body is solder foil or at least Sn
It is a thin film of a metal containing.

An electronic component connecting method according to an eighteenth invention of the present application, which is provided for solving the above-mentioned problems, is the electronic component connecting method according to any one of claims 10 to 17. The electronic parts and other electronic parts are semiconductor chips or wiring boards.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of a connecting structure and a connecting method for electronic parts according to the present invention will be described below with reference to the drawings. Here, in describing an embodiment of a connection structure and a connection method for an electronic component according to the present invention, the first electronic component 1 and the second electronic component 2 may be regarded as, for example, a semiconductor chip and a mounting substrate. . 1 and 2 are diagrams showing an embodiment of a connection structure and a connection method for an electronic component according to the present invention. As shown in FIG. 1A, an electrode portion 11 is formed on the surface of the first electronic component 1, and an Au bump 12 is formed in a stud bump shape on the electrode portion 11 by a wire bonding method. . Next, the supply body 3 whose surface is formed of a low melting point metal containing Sn as a main component is made to face the Au bump 12 (FIG. 1 (b)).
The supply body 3 is pressed against the top of the u bump 12 (FIG. 1C). By doing so, the thin film 31 of a low melting point metal containing Sn as a main component is transferred to the top of the Au bump 12 (FIG. 2A), and at the same time, a plurality of thin films formed on the first electronic component 1 are formed. A work called coining for adjusting the height of the Au bumps 12 is also performed.

This coining keeps the heights of the Au bumps 12 substantially constant, and when bonding flip chips or the like,
The purpose is to make the pressure applied to each of the Au bumps 12 substantially constant when the Au bumps 12 are pressed against the electrode portion 21 side. That is, by doing so, when the Au bump 12 is pressed against the electrode portion 21 side, a large pressure is applied to the specific electrode portion 12 and damage to a semiconductor element or the like formed under the electrode portion 12 can be reduced. it can. At this time, the Au bumps 12 are set to 100
By heating to about 200 ° C., the low melting point metal can be satisfactorily transferred.

The supply member 3 is preferably in the form of a sheet, and more preferably a solder foil placed on a flat stage or a metal plate having an Sn plating layer formed on the surface thereof. Further, in order to improve mass productivity, a long tape-shaped solder foil housed in a reel may be used. Here, at least S formed on the surface of the supply body 3
The metal layer containing n and having a lower melting point than Au specifically refers to a metal having a lower melting point than the materials forming the electrodes to be joined and easily compatible with them in a molten state. For example, when the electrode is Au, Sn, Sn-
These include Pb eutectic solder, Pb-free solder, and the like. Further, the top of the Au bump means Au.
Even if the bump 12 is deformed by the above-mentioned pressing, the height of the Au bump 12 is designed to such an extent that the supply body 3 (solder or Sn) and the electrode portion 11 do not come into contact with each other. Refers to the area. As described above, the Au bump 12
The stud shape is desirable. This is because when the Au bump 12 is pressed against the supply body 3, the amount of deformation is large when the tip has a sharp shape, so that the solder or Sn of the supply body 3 can be efficiently transferred to the Au bump 12. Because you can

Next, the Au bump 22 of the second electronic component 2 is opposed to the Au bump 12 having the thin film 31 formed on the end surface 121 which is coined and made flat (see FIG. 2).
(B)), the Au bump 12 with respect to the Au bump 22
Is pressed (FIG. 2 (c)).

Next, by heating the first electronic component 1 and the second electronic component 2, the end face 1 of the Au bump 12 is heated.
The solder or Sn forming the thin film 31 of 21 diffuses into the Au bumps 22, and the Au bumps 12 and the Au bumps 22
Are metallically joined via the melted and solidified thin film 31. By the connection method as described above, the connection structure of the first electronic component 1 and the second electronic component 2 as shown in FIG. 2D is obtained. That is, in this process,
By continuously performing the step of transferring the low melting point metal and the step of joining, it is possible to join the surface of the solder or Sn at a stage where natural oxidation does not proceed. Furthermore, by supplying a liquid or sheet-like resin on the IC chip or the wiring substrate in advance at the time of joining, it is possible to perform resin sealing simultaneously with metal joining.

(Other Embodiments) Other embodiments of the connection structure and connection method for electronic parts according to the present invention will be described below with reference to the drawings. 3 to 4 are views showing another embodiment of a connection structure and a connection method for an electronic component according to the present invention. The other embodiment of the present invention is different from the above-described one embodiment of the present invention in that the Au bumps or the like are not formed on the electrode portion 21 of the second electronic component 2 and the first electronic component The connection structure between the first electronic component 2 and the second electronic component 2 is the Au bump 1.
2 is a connection structure between the electrode portion 21 and the electrode 2.

As shown in FIG. 3A, an electrode portion 11 is formed on the surface of the first electronic component 1, and the Au bump 12 is formed on the electrode portion 11 by a wire bonding method.
Are formed in a stud bump shape. Next, the supply body 3 whose surface is made of solder or a low melting point metal containing Sn as a main component is opposed to the Au bump 12 (FIG. 3B), and the supply is applied to the top of the Au bump 12. The body 3 is pressed (FIG. 3 (c)).

Next, the electrode portion 21 of the second electronic component 2 is opposed to the Au bump 12 that is coined by pressing the supply member 3 and has the thin film 31 formed on the flattened end surface 121 (see FIG. 4). (B)), The Au bump 12 is pressed against the electrode part 21 (FIG.4 (c)).

Next, by heating the first electronic component 1 and the second electronic component 2, the end face 1 of the Au bump 12 is heated.
The solder or Sn forming the thin film 31 of 21 is the electrode portion 21.
The Au bump 12 and the electrode portion 21 are melted and
It is metallically bonded via the solidified thin film 31. By the connection method as described above, the connection structure of the first electronic component 1 and the second electronic component 2 as shown in FIG. 4D is obtained.

When the gold-tin eutectic bonding method is used as in the present invention, the electrode portion 21 of the second electronic component 2 and the bumps formed on the electrode portion 21 need to be Au, but the flux and the reducing action In the case of using such a medium, the electrode portion 21 and the bump of the second electronic component 2 may be made of Cu.

【The invention's effect】

As described above, according to the connection structure and the connection method of the electronic component of the present invention, the bump (Au)
It is possible to bond electronic components with low stress by utilizing the diffusion phenomenon between the semiconductor and the supply body (solder or Sn). Further, by performing the supply step immediately before the joining process, there are no restrictions on the storage conditions of the material such as the prevention of whiskers and oxidation / diffusion, which have been a problem in the conventional joining using solder or Sn. The new surface can be used for joining.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a connection structure and a connection method for an electronic component according to the present invention.

FIG. 2 is a diagram showing an embodiment of a connection structure and a connection method for an electronic component according to the present invention.

FIG. 3 is a diagram showing another embodiment of a connection structure and a connection method for an electronic component according to the present invention.

FIG. 4 is a diagram showing another embodiment of a connection structure and a connection method for an electronic component according to the present invention.

FIG. 5 is a diagram showing a conventional electronic component connection structure and connection method.

[Explanation of symbols]

1. First electronic component 2. Second electronic component 3. Supplier 11. Electrode part 12. Au bump 21. Electrode part 22. Au bump 31. Thin film 121. End face

Claims (18)

[Claims] 1. A connection structure of an electronic component, wherein an electrode portion provided on one electronic component and an electrode portion provided on another electronic component are connected via Au bumps. An Au bump is formed on the electrode portion, and a top of the Au bump is pressed by pressing a supply body containing at least Sn and at least a surface of which is formed of a metal layer having a melting point lower than that of Au. A step of forming a thin film by transferring the metal of the metal layer to, and a step of pressing the electrode portion of the other electronic component to the top of the Au bump in the state where the thin film is formed, and heating. An electronic component connection structure, characterized in that an electrode portion of one electronic component and an electrode portion of another electronic component are connected via the thin film and the Au bump. 2. The connection structure for electronic parts according to claim 1, wherein the Au bump has a stud bump shape. 3. The connection structure for an electronic component according to claim 1, wherein the Au bump is a plated bump. 4. The connection structure for an electronic component according to claim 1, wherein an Au layer is formed on a surface of an electrode portion of the other electronic component. 5. The connection structure for electronic components according to claim 4, wherein the Au layer has a stud bump shape. 6. The connection structure for an electronic component according to claim 4, wherein the Au layer is a plated bump. 7. The connection of an electronic component according to claim 1, wherein the supply member is a metal plate having a Sn plating layer or a solder plating layer formed on a surface thereof. Construction. 8. The supply body is a solder foil or at least S
7. The connection structure for electronic parts according to claim 1, wherein the connection structure is a metal thin film containing n. 9. The electronic component and the other electronic component are semiconductor chips or wiring boards.
9. A connection structure for an electronic component according to claim 8. 10. An A is provided on an electrode portion provided on one electronic component.
A u-bump is formed, and a supply body formed of a metal layer containing at least Sn and having at least a surface having a melting point lower than that of Au is pressed on the top of the Au bump to press the Au bump.
A step of forming a thin film by transferring the metal of the metal layer to the top of the bump, and pressing an electrode portion provided on the other electronic component on the top of the Au bump in the state where the thin film is formed, And a step of heating the one electronic component and the other electronic component, and a step of connecting the electrode portion of the one electronic component and the electrode portion of the other electronic component through the thin film and the Au bump. A characteristic method for connecting electronic components. 11. The method according to claim 10, wherein the Au bump has a stud bump shape. 12. The method for connecting electronic components according to claim 10, wherein the Au bump is a plated bump. 13. Au on the surface of the electrode portion of the other electronic component.
The method for connecting electronic components according to claim 10, wherein a layer is formed. 14. The method for connecting electronic components according to claim 13, wherein the Au layer has a stud bump shape. 15. The method of connecting electronic components according to claim 13, wherein the Au layer is a plated bump. 16. The connection of an electronic component according to claim 10, wherein the supply body is a metal plate having a Sn plating layer or a solder plating layer formed on a surface thereof. Method. 17. The method of connecting electronic components according to claim 10, wherein the supply body is a solder foil or a metal thin film containing at least Sn. 18. The method of connecting an electronic component according to claim 10, wherein the one electronic component and the other electronic component are semiconductor chips or wiring boards.