JPH10125726A - Substrate and its connection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate which can beforehand prevent breaking of a connection part caused by a concentrated stress, by shaping connected bumps reliably into such a predetermined configuration as to avoid any concentrated stress, and also to provide a method for connecting the substrate. SOLUTION: First, as shown in the drawing (A), an IC chip 10 having terminal electrode parts 11 and columnar bumps 12C of solder formed on the electrode parts 11 is positioned above terminal electrode parts 18 of a circuit substrate 16 with the side of the bumps 12C facing down, the bumps 12C are heated to be melted by reflow, the entire IC chip 10 is moved in an arrowed direction 30 until the surface of a protective film 14 covering a terminal electrode 11 side of the chip 10 come into contact with the surface of a protective film 20 on the circuit substrate 16, and then the bumps 12C are cooled and fixedly set. As a result, as shown in the drawing (B), the bumps 12C are changed to drum-shaped bumps 12D having the same shape as openings 22 made in the protective film 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate and a method for connecting the substrates, and more particularly, to a substrate such as a semiconductor chip or a circuit substrate capable of shaping the shape of a bump at the time of connection and a method for connecting the substrates. is there.

[0002]

2. Description of the Related Art Conventionally, connection between a bump formed on a terminal electrode portion of an IC chip and a terminal electrode portion of a circuit board is shown in FIG.
As shown in (A), the bump 12A formed on the terminal electrode portion 11 of the IC chip 10 having the protective film 14 formed on the surface on the side of the terminal electrode portion 11 is located above the terminal electrode portion 18 of the circuit board 16 opposite to the bump 12A. By moving the entire IC chip 10 in the direction of the arrow 34 while heating the bump 12A after the alignment, the bump 12A is brought into contact with the terminal electrode portion 18 of the circuit board 16, and the bump 12A is cooled and fixed. Bump 12 previously mounted on terminal electrode portion 18
A was performed by heating and melting A.

However, according to the above-described method, the bump 12B after connection has a shape in which the diameter at the center is larger than the diameter at both ends as shown in FIG. There is a problem that the connection portion is easily broken due to concentration.

In order to solve such a problem, Japanese Patent Application Laid-Open No. Hei 5-144874 discloses a method in which a bump is heated and melted so that the bump is connected to a terminal electrode portion of an opposing circuit board and, at the same time, an IC is formed.
A method is described in which the shape of the bump is made into a drum shape in which the diameter at the center is smaller than the diameter at both ends by raising the chip by a predetermined distance.

[0005]

However, in the above-mentioned prior art, the bump is shaped like a drum using the surface tension of the bump by raising the IC chip by a predetermined distance. There was a problem that it was difficult to do. Further, there is a problem that the connection method is limited to only the reflow.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the shape of a bump after connection can be surely shaped into a predetermined shape regardless of the connection method of reflow and thermocompression bonding. It is an object of the present invention to provide a substrate and a method of connecting substrates that can prevent a connection portion from being broken due to stress concentration by setting a predetermined shape to a shape in which stress concentration does not occur.

[0007]

According to a first aspect of the present invention, there is provided a substrate which is connectable to a substrate having a bump formed on a terminal electrode portion and has a terminal electrode portion. An opening for shaping the bump into a predetermined shape when connecting the terminal electrode portion to a bump formed on the terminal electrode portion of another substrate so that the bump shape after connection becomes a predetermined shape. The part is formed on the surface with a protective film provided on the terminal electrode part.

According to the first aspect of the present invention, the protective film on the surface of the substrate is provided with an opening for shaping the bump into a predetermined shape after connection with another substrate having the bump formed on the terminal electrode portion. ing. Accordingly, by making the predetermined shape a shape in which stress concentration is unlikely to occur, it is possible to reliably shape the bump into a shape in which the same stress concentration as the shape of the opening is unlikely to occur, and the connection caused by the stress concentration after the connection is made. Breakage of the portion can be prevented beforehand.

A substrate according to a second aspect of the present invention is a substrate connectable to a substrate having a terminal electrode portion and having a bump formed on the terminal electrode portion, so that the bump shape after connection becomes a predetermined shape. An opening for shaping the bump into a predetermined shape at the time of connection between the bump and the terminal electrode of another substrate has a protective film provided on the terminal electrode so that the opening surrounds the bump. It is formed in.

According to the second aspect of the present invention, the opening for shaping the bump into a predetermined shape after connection with the terminal electrode portion of another substrate is provided in the protective film on the substrate surface so as to surround the bump. ing. Accordingly, by making the predetermined shape a shape in which stress concentration is unlikely to occur, it is possible to reliably shape the bump into a shape in which the same stress concentration as the shape of the opening is unlikely to occur, and the connection caused by the stress concentration after the connection is made. Breakage of the portion can be prevented beforehand.

According to a third aspect of the present invention, in the method of connecting a substrate for connecting a bump formed on a terminal electrode portion of a first substrate and a terminal electrode portion of a second substrate, the bump shape after the connection is formed. The protective film provided on the terminal electrode portion has an opening for shaping the bump into a predetermined shape when the bump is connected to the terminal electrode portion of the second substrate so that the bump has a predetermined shape. The bump is formed on one of the surfaces of the first substrate and the second substrate, and the bump is connected to a terminal electrode portion of the second substrate by reflow or thermocompression bonding.

According to a third aspect of the present invention, there is provided a method of connecting a substrate.
When the bump formed on the terminal electrode portion of the first substrate and the terminal electrode portion of the second substrate are connected by reflow or thermocompression bonding, the bump is formed on one of the surfaces of the first substrate and the second substrate. The bump formed on the terminal electrode portion of the first substrate is shaped into a predetermined shape by the opening on the terminal electrode portion of the protective film. Accordingly, by making the predetermined shape a shape in which stress concentration is unlikely to occur, it is possible to reliably shape the bump into a shape in which the same stress concentration as the shape of the opening is unlikely to occur, and the connection caused by the stress concentration after the connection is made. Breakage of the portion can be prevented beforehand.

The substrate according to the present invention includes, in addition to a circuit board such as a printed wiring board, an IC chip having circuits and terminal electrodes, an IC package having bumps, and the like. Therefore, the substrate according to the first and second aspects of the invention, and the first substrate and the second substrate according to the third aspect of the invention may be any of a circuit board, a semiconductor chip, an IC package, and the like. The connection method of the board described is
The present invention can be applied to connection between a circuit board including an IC package and a semiconductor chip, connection between circuit boards including an IC package and the like, and connection between semiconductor chips.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] Hereinafter, a substrate and a method for connecting the substrates according to the present invention will be described in detail with reference to the drawings.

First, based on FIGS. 1 (A) and 1 (B), a circuit board as a board according to a first embodiment of the present invention and I
A method for connecting to the C chip will be described.

The circuit board 16 according to the present embodiment has a structure shown in FIG.
As shown in FIG. 4A, a drum-shaped opening is formed on the surface on the side of the terminal electrode portion 18 at a substantially central portion on the terminal electrode portion 18 in which the diameter of the central portion in the vertical direction with respect to the upper surface of the terminal electrode portion 18 is smaller than the diameter of both ends. A protective film 20 such as a resist having a hole 22 is provided.

The drum-shaped opening 22 is formed by the following steps. First, as shown in FIG. 3A, an anisotropic etching resin 50 is applied to the surface of the circuit board 16 on the side of the terminal electrode portion 18 so as to have a thickness corresponding to half the height of the opening 22. Mask 5 on the surface of anisotropic etching resin 50
Etching is performed after placing No. 2. The mask 5
2 is provided with a mask opening 52A, and the mask 52 is placed so that only the surface substantially vertically above the surface of the terminal electrode portion 18 is masked. As a result of the above-described etching, the hatched portion of FIG. 3B in the anisotropic etching resin 50 is removed, and a resin remaining portion 50 </ b> A having the same shape as the lower half of the opening 22 remains on the surface of the terminal electrode portion 18. In addition, the magnitude of the inclination of the inclined portion of the resin remaining portion 50A can be adjusted by adjusting the etching rate at the time of etching.

Next, as shown in FIG. 3 (C), a protective film 20 is formed on the surface of the circuit board 16 on the side of the terminal electrode section 18 in the opening section 2.
2 and the etching is performed after the mask 54 is placed on the surface of the protective film 20 as shown in FIG. The mask 54 has a mask opening 5.
4A are provided, and the mask 54 is placed such that the center of the mask opening 54A is located substantially vertically above the center of the terminal electrode portion 18. As a result of the above-described etching, the protective film removing portion 20A shown in the hatched portion of FIG. By adjusting the etching rate, it is possible to adjust the magnitude of the inclination of the inclined portion of the protective film removing portion 20A.

Finally, only the resin residue 50A is removed by etching, so that the drum-shaped opening 2 shown in FIG.
2 are formed.

At this time, it is preferable that the opening 22 is formed so that the volume thereof is equal to the volume of the bump 12C opposed thereto.

The circuit board 16 formed as described above and I
Next, a method of connecting to the C chip 10 will be described.

First, as shown in FIG. 1A, a columnar bump 12C made of solder is
The IC chip 10 formed thereon is positioned above the terminal electrode portion 18 of the circuit board 16 with the bump 12C side facing down, and then the entire IC chip 10 is moved in the direction of arrow 30 and the bump 12C is heated by reflow. The IC chip 10 is melted and the terminal electrode portion 11 of the IC chip 10 is melted.
Of the protective film 14 covering the side surface and the circuit board 16
The bump 12C is moved to a position where it comes into contact with the surface of the upper protective film 20 and stopped, and the bump 12C is cooled and fixed.

FIG. 1B shows a state in which the IC chip 10 and the circuit board 16 are connected by the above connection method. FIG.
As shown in (B), the bump 12C melted by being heated at the time of connection is constrained by the shape of the opening 22 provided in the protective film 20 and has the same shape as the opening 22 after connection. That is, it becomes the drum-shaped bump 12D.

As described above, according to the first embodiment of the present invention, the protective film 20 on the circuit board 16 has
2, the bump 12C and the terminal electrode portion 18 are provided.
When the bumps 12C are connected to each other, the bumps 12C can be reliably shaped into a drum shape in which stress concentration does not easily occur.
Breakage of the connection part due to stress concentration after the connection between the 2C and the terminal electrode part 18 can be prevented beforehand.

[Second Embodiment] Next, based on FIG.
A method for connecting a circuit board and an IC chip as a board according to the second embodiment of the present invention will be described.

The IC chip 10 according to the second embodiment includes:
As shown in FIG. 2, a bump 12E formed in a columnar shape at a substantially central portion on the terminal electrode portion 11 on the surface on the terminal electrode portion 11 side.
Protective film 1 provided with a drum-shaped opening 22B so as to surround
4B. The opening 22B provided in the protective film 14B can be formed in the same step as the step of forming the opening in the first embodiment. At this time, it is preferable to form the opening 22B such that the volume thereof is equal to the volume of the bump 12E.

As described above, the I on which the protective film 14B is formed
Next, a method of connecting the C chip 10 and the circuit board 16 will be described.

First, the bump 12E is positioned above the terminal electrode portion 18 of the circuit board 16 with the IC chip 10 facing down on the bump 12E side, and then the entire IC chip 10 is moved in the direction of arrow 32 and the bump 12E is reflowed.
E is melted by heating, and the IC chip 10 is replaced with the IC chip 1
Protective film 14B covering the surface on the side of terminal electrode portion 11
Is moved to a position where the surface of the protective film 20B on the circuit board 16 comes into contact with the surface of the protective film 20B and is stopped, and the bump 12E is cooled and fixed.

According to the connection method described above, the bump 12E melted by being heated at the time of connection is connected to the protective film 14
After being connected by being restrained by the shape of the opening 22B provided in B, the shape becomes the same as that of the opening 22B, that is, a drum shape after connection.

As described above, in the method of connecting a substrate to a substrate according to the second embodiment of the present invention, the bump 12E and the terminal are provided by providing the drum-shaped opening 22B in the protective film 14B on the IC chip 10. When connecting to the electrode part 18,
Since the bumps 12E can be surely shaped into a drum shape in which stress concentration is unlikely to occur, breakage of the connection portion due to stress concentration after connecting the substrate can be prevented.

In each of the above embodiments, the case where the bumps formed on the terminal electrodes of the IC chip are melted by reflow and connected to the terminal electrodes on the circuit board has been described. The connection is not limited, and connection may be made by thermocompression bonding. In this case, after the bump made of gold (Au), solder, or the like is positioned above the terminal electrode portion of the circuit board, the bump is heated to a temperature lower than the bump liquidus temperature and thermocompression bonded to the terminal electrode portion. . At this time, the heated and softened bumps are restrained by the drum-shaped opening formed in the protective film and undergo plastic deformation.
It becomes a drum-shaped bump.

Further, in each of the above embodiments, the case where the opening portion formed in the protective film is formed so that the volume thereof is equal to the volume of the bump has been described. However, the present invention is not limited to this. Instead, the volume of the opening may be equal to or less than the volume of the bump. If the volume of the opening is smaller than the volume of the bump, a gap is formed between the protective film of the IC chip and the protective film of the circuit board after connection. Further, reliability can be improved.

In each of the above embodiments, the case where bumps are formed on the terminal electrodes on the IC chip side and connected to the terminal electrodes on the circuit board has been described. However, the present invention is not limited to this. The same effect can be obtained when a bump is formed on the terminal electrode portion on the circuit board side.

In each of the above embodiments, the case where the shape of the opening is a drum shape has been described. However, the present invention is not limited to this. Can be.

In each of the above embodiments, the case where the connection between the IC chip and the circuit board is performed has been described. However, the present invention is not limited to this.
Connection between package and substrate, IC chips or IC
The present invention can be applied to connection between circuit boards including a package.

Further, in each of the above embodiments, the bump shape is cylindrical, but the present invention is not limited to this. The present invention is also applicable to a spherical bump or a ball bump.

[0037]

As described above, in the substrate according to the first aspect, an opening for shaping a bump into a predetermined shape after connection with another substrate having a bump formed on a terminal electrode portion has a substrate surface. Since the protective film is provided on the protective film, the predetermined shape has a shape in which stress concentration is unlikely to occur, so that the bump can be surely shaped into a shape in which the same stress concentration as the opening portion does not easily occur. This has the effect that breakage of the connection portion due to subsequent stress concentration can be prevented.

Further, in the substrate according to the second aspect, an opening for shaping a bump into a predetermined shape after connection with a terminal electrode portion of another substrate is provided in a protective film on the surface of the substrate so as to surround the bump. Therefore, by making the predetermined shape a shape in which stress concentration is unlikely to occur, it is possible to reliably shape the bump into a shape in which the same stress concentration as the shape of the opening does not easily occur, and to reduce the stress concentration after connection. This has the effect that breakage of the connection part due to the occurrence can be prevented beforehand.

Further, in the method of connecting a substrate according to the third aspect, when the bump formed on the terminal electrode portion of the first substrate and the terminal electrode portion of the second substrate are connected by reflow or thermocompression bonding, By the opening portion on the terminal electrode portion of the protective film formed on one surface of the first substrate and the second substrate,
Since the bump formed on the terminal electrode portion of the first substrate is shaped into a predetermined shape, by making the predetermined shape a shape in which stress concentration is unlikely to occur, the same stress concentration as the shape of the opening portion is formed in the bump. This has the effect that the shape can be reliably formed into a shape that is unlikely to occur, and the breakage of the connection portion due to the stress concentration after connection can be prevented.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic side views illustrating a substrate and a method of connecting the substrates according to the first embodiment of the present invention, wherein FIG. 1A illustrates a state before connection, and FIG. 1B illustrates a state after connection; is there.

FIG. 2 is a schematic side view illustrating a substrate and a method of connecting the substrates according to a second embodiment of the present invention.

FIG. 3 is a schematic side view showing a step of forming a drum-shaped opening provided in a protective film.

4A and 4B are schematic side views illustrating a conventional method of connecting a substrate and a substrate, wherein FIG. 4A is a diagram illustrating a state before connection, and FIG. 4B is a diagram illustrating a state after connection.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 IC chip (substrate) 11 Terminal electrode part 12 Bump 14 Protective film 16 Circuit board (substrate) 18 Terminal electrode part 20 Protective film 22 Opening part

Claims (3)

[Claims] 1. A substrate which is connectable to a substrate having a bump formed on a terminal electrode portion and has a terminal electrode portion, wherein the terminal electrode portion and the terminal electrode portion have a predetermined shape after connection. A substrate having an opening for shaping the bump into a predetermined shape at the time of connection with a bump formed on a terminal electrode portion of another substrate and having a protective film provided on the terminal electrode portion formed on the surface thereof. . 2. A substrate connectable to a substrate having a terminal electrode portion and having a bump formed on the terminal electrode portion, wherein the bump and the other bump are connected to each other so that the bump shape after connection becomes a predetermined shape. A substrate on a surface of which a protective film provided on the terminal electrode portion is formed such that an opening for shaping the bump into a predetermined shape at the time of connection with the terminal electrode portion of the substrate surrounds the bump. 3. A method of connecting a substrate for connecting a bump formed on a terminal electrode portion of a first substrate and a terminal electrode portion of a second substrate, wherein the bump shape after connection is a predetermined shape. An opening for shaping the bump into a predetermined shape at the time of connection between the bump and the terminal electrode portion of the second substrate is provided with a protective film provided on the terminal electrode portion of the first substrate and the second substrate. A method of connecting a substrate, comprising forming the bump on one of the surfaces and connecting the bump to a terminal electrode portion of the second substrate by reflow or thermocompression bonding.