JP2000077485A - How to mount electronic components with bumps - Google Patents

Abstract

(57) [Problem] To provide a mounting method of a bumped electronic component capable of preventing a bonding defect. SOLUTION: When mounting a chip 6 provided with a bump 6a on a package 4 provided with an elongated electrode 4a, the bump 6a is attached to the electrode 4a by a bonding tool.
And vibrates the chip 6 via the bonding tool in the longitudinal direction of the electrode 4a. When the electrodes 4a are provided in a plurality of different directions, the vibration is applied in the longitudinal direction of the electrode having a large number of electrodes. Thereby, the variation in the contact state between the bump 6a and the electrode 4a can be reduced, and the bonding quality can be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for mounting an electronic component with bumps on a substrate.

[0002]

2. Description of the Related Art As a method for mounting an electronic component on a substrate,
A method using ultrasonic pressure welding is known. When mounting electronic components with bumps using this method, ultrasonic vibration is applied to the electronic components while pressing the bumps on the electrodes provided on the substrate, and the contact surfaces between the bumps and the electrodes are mutually rubbed. Thereby, the contact surfaces are joined.

[0003]

By the way, there are various types of shapes of the electrodes provided on the substrate. In general, the electrode to which the above-described bump is bonded is often a part of a circuit pattern on a substrate, and in such a case, the electrode has an elongated shape that is long in one direction. The cross section of the electrode in the width direction is generally a mountain having an uneven upper surface. When a bump is pressed on an electrode having such a mountain cross section, the contact point between the bump and the electrode is determined at any position in the width direction of the electrode. , The contact state between the bump and the electrode is not constant, and the strength of the pressed state occurs. For this reason, in the case where the bumps are ultrasonically pressure-welded to the conventional elongated electrode, there is a problem that the bonding quality is not stable due to the variation in the contact state, and a bonding failure such as peeling of the bonding portion or insufficient bonding strength occurs. Was.

Accordingly, an object of the present invention is to provide a mounting method of an electronic component with bumps, which can prevent bonding failure.

[0005]

According to a first aspect of the present invention, there is provided a method of mounting an electronic component with bumps, comprising mounting the electronic component with bumps on a substrate provided with elongated electrodes. Pressing a bump of the bumped electronic component against the electrode with a bonding tool;
Vibration is applied to the bumped electronic component in the longitudinal direction of the electrode via the bonding tool.

According to a second aspect of the present invention, there is provided a method of mounting an electronic component with bumps according to the first aspect, wherein the electrodes are provided in a plurality of different directions. Vibration was applied in the direction in which the distribution in the longitudinal direction of the electrode was the largest.

According to the invention described in each claim, by applying vibration in the longitudinal direction of the elongated electrode, variation in the contact state between the bump and the electrode can be reduced, and the bonding quality can be stabilized.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. 1 is a front view of a bonding apparatus according to an embodiment of the present invention, FIGS. 2 and 3 are partial plan views of the bonding apparatus, FIG. 4 is a perspective view of a chip and a package to be bonded, and FIG. 5 is an enlarged perspective view of the bump and the electrode, and FIGS. 5B and 5C are cross-sectional views of the bump and the electrode.

First, the bonding apparatus will be described with reference to FIG. In FIG. 1, a holding stage 2 of a package 4 which is a box-shaped substrate is mounted on an XY table 1. The holding stage 2 holds the package 4 with the holder 3
And hold it. On the side of the holding stage 2, a tray 5 for storing a chip 6, which is an electronic component with bumps, is provided.

[0010] Above the XY table 1, a bonding head 10 is provided. Bonding head 10
Is the bonding tool 1 fixed to the tool holder 12
The bonding tool 11 includes the vibrator 1
3 is attached. By driving the vibrator 13, vibration is applied to the chip 6 held by the bonding tool 11 via the bonding tool 11. The direction of the vibration applied at this time depends on the bonding tool 11.
In the longitudinal direction.

The tool holder 12 is rotatably mounted on the lifting block 14. A belt 16 is tuned to a pulley 15 connected to the tool holder 12 and a pulley 17 connected to a head turning motor 18 disposed on the lifting block 14. By driving the head turning motor 18, the tool holder 12 rotates about the vertical axis, so that the bonding tool 11 also rotates about the vertical axis, and freely changes the position of the chip 6 held by suction in the rotation direction. be able to.

The lifting block 14 is moved up and down by a Z-axis lifting mechanism 19 driven by a Z-axis motor 20. Z-axis motor 20, head rotation motor 18, and XY
The table 1 is driven by a motor drive unit 21.
The vibrator 13 is driven by a vibrator drive unit 23. The motor drive unit 21 and the vibrator drive unit 23 include a control unit 22
Is controlled by Therefore, by controlling the operation of each unit by the control unit 22, the chip 6 stored in the tray 5 is picked up by the bonding tool 11, the chip 6 is aligned with the direction of the package 4, and mounted on the package 4. Bonding can be performed while applying sonic vibration.

Next, the relationship between the chip 6 and the direction of the package will be described with reference to FIG. In FIG. 2, XY
A large number of chips 6 are stored in a grid on the tray 5 arranged on the stage. A plurality of bumps 6a are formed on the lower surface of the chip 6, and the chip 6 has directionality at the time of bonding depending on the arrangement direction of the bumps 6a. On the bottom of the package 4 clamped on the holding stage 2, electrodes 4a are formed corresponding to the arrangement of the bumps 6a. The electrode 4a has an elongated shape,
Similarly, it has directionality. Package 4
Are clamped on the holding stage 2 and the electrodes 4a
Are aligned with the X-axis direction.

This bonding apparatus is configured as described above, and its operation will be described below. First, in FIG. 1, the XY table 1 is driven to move the chip 6 to be bonded on the tray 5 below the suction position of the bonding tool 11. Then, as shown in FIG. 3A, with the longitudinal direction of the bonding tool 11 aligned with the Y-axis direction, the Z-axis motor 20 is driven to lower the bonding tool 11, and the chip 6 is sucked. Pick up. After raising the bonding tool 11, the XY table 1 is driven to
The package 4 is located below the package 1. At this time, FIG.
As shown in (b), the head turning motor 18 is driven to turn the bonding tool 11 by 90 ° so that the longitudinal direction of the bonding head 11 is aligned with the X-axis direction.
Thereby, the direction of the chip 6 held by the bonding tool 11 and the direction of the package 4 match.

In this state, the bonding tool 11
Is lowered, as shown in FIG.
The bumps 6a are aligned with the electrodes 4a of the package 4 and mounted. Therefore, when the vibrator 13 is driven while maintaining this direction to apply vibration to the chip 6 via the bonding tool 11, the vibration is applied to the electrode 4a of the package 4.
In the longitudinal direction (X-axis direction).

Thereafter, while the chip 6 is pressed against the package 4 with a predetermined load by the bonding tool 11, the vibrator 13 is driven to apply vibration to the chip 6, thereby bonding the bump 6a to the electrode 4a. .
The vibration applied during this bonding will be described with reference to FIG. As shown in FIG. 5A, the electrode 4a
Has an elongated shape, the width thereof is substantially the same as the size of the bump 6a, and the cross section in the width direction is a mountain-shaped cross section. At the time of bonding, the bump 6a is brought into contact with the electrode 4a, and vibration is applied while pressing.

FIGS. 5B and 5C show the direction of the vibration at this time, and FIG. 5B shows the direction of the vibration application in the present embodiment. That is, the bump 6a
Is in contact with the upper surface of the electrode 4a, and vibration is applied in the longitudinal direction of the elongated electrode 4a as shown by an arrow a. Since the electrode 4a has a substantially uniform height in the longitudinal direction, even if the bump 6a is displaced relative to the electrode 4a due to vibration, the bump 6a is not displaced in the vertical direction and is always constant. Vibration is applied in a state where the contact state is maintained.

On the other hand, when vibration is applied in the width direction of the electrode 4a (arrow b) as shown in FIG.
The lower end of the bump 6a is displaced along the surface of the mountain-shaped cross section of the electrode 4a (see arrow c). As a result, the bonding is performed while the bump 6a repeatedly moves up and down. That is, the contact state between the lower end portion of the bump 6a and the electrode 4a repeatedly fluctuates greatly, and the strength of the pressed state is generated. As a result, the friction between the bump 6a and the surface of the electrode 4a is not stably performed, and the bonding result varies. . In the present embodiment, in order to prevent such instability of the frictional state, vibration is applied in a vibration direction in which the bump 6a is not displaced with respect to the width direction of the electrode 4a, that is, in the longitudinal direction of the electrode 4a. It is.

As described above, when bonding a bump to an elongated electrode, by applying vibration in the longitudinal direction of the electrode, stable and consistent bonding can be performed. If a large number of electrodes are formed not only in one direction but also in different directions and the longitudinal direction of the electrode cannot be uniquely determined, the vibration in the direction in which the longitudinal distribution of the electrode is the largest is obtained. Is given. As a result, variations in the bonding result can be suppressed as much as possible, and the overall bonding quality can be maintained.

[0020]

According to the present invention, the vibration is applied in the longitudinal direction of the elongated electrode during the ultrasonic pressure welding, so that the variation in the contact state between the bump and the electrode when the bump is pressed can be reduced. Therefore, the joining quality can be stabilized.

[Brief description of the drawings]

FIG. 1 is a front view of a bonding apparatus according to an embodiment of the present invention.

FIG. 2 is a partial plan view of the bonding apparatus according to the embodiment of the present invention;

FIG. 3 is a partial plan view of the bonding apparatus according to the embodiment of the present invention;

FIG. 4 is a perspective view of a chip and a package to be bonded according to an embodiment of the present invention.

5A is an enlarged perspective view of a bump and an electrode according to an embodiment of the present invention. FIG. 5B is a cross-sectional view of the bump and an electrode according to the embodiment of the present invention. Cross section of bump and electrode

[Explanation of symbols]

 Reference Signs List 4 package 4a electrode 6 chip 6a bump 10 bonding head 11 bonding tool 13 vibrator

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masafumi Hinosaku 1006 Kadoma, Kadoma, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. 4M105 BB04 EE02 EE16

Claims (2)

[Claims] 1. A method of mounting an electronic component with a bump on a substrate provided with an elongated electrode, the method comprising: pressing a bump of the electronic component with a bump against the electrode with a bonding tool. A method of mounting an electronic component with bumps, wherein vibration is applied to the electronic component with bumps in the longitudinal direction of the electrode via the bonding tool. 2. The electronic device with bumps according to claim 1, wherein when the electrodes are provided in a plurality of different directions, the vibration is applied in a direction in which the distribution of the electrodes in the longitudinal direction is the largest. Component mounting method.