JP2003197683A - Apparatus and method for bonding electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and method for bonding an electronic component by which bonding quality is secured by preventing bonding efficiency from being deteriorated. <P>SOLUTION: The bonding apparatus for bonding the electronic component 9 to a board 4 by pressurization and ultrasonic vibration is provided with an infrared irradiation lamp 18 for heating the component 9 held by a tool 8 from its lower side separately from the tool 8. After previously heating and warming the gold electrode 9a of the component 9 in advance of mounting the component 9 to the board 4, the gold electrode 9a is pressurized to the electrode 4a of the board 4 to apply the ultrasonic vibration to the component 9 by a vibrator 8c. Thus, the temperature of a bonding surface is raised without causing softening as the result of heating of the board 4. Consequently, ultrasonic bonding is performed efficiently and the bonding quality can be secured. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component bonding apparatus and method for bonding an electronic component to a substrate.

[0002]

2. Description of the Related Art As a method for bonding electronic components such as bumped electronic components to a substrate, a method using ultrasonic pressure welding is known. In this method, ultrasonic vibration is applied while pressing the bumps of the electronic component against the substrate, and the bumps and the electrodes and other bonding surfaces of the substrate are rubbed against each other for bonding. In order to perform this bonding efficiently with good bonding quality, it is effective to press the bump against the electrode of the substrate with an appropriate pressure bonding load and heat the bonding portion between the bump and the electrode of the substrate. .

Therefore, conventionally, a bonding apparatus for electronic parts is provided with a heating means for heating the electronic parts or the substrate in advance prior to the bonding operation.
As a heating method for heating an electronic component, a heating tool is generally incorporated in a bonding tool that holds the electronic component and presses it against the substrate. A method of providing a heating element on the table has been used.

[0004]

However, the above-mentioned conventional heating method has the following disadvantages. First, in the method in which the heating element is incorporated in the bonding tool, the vibration characteristics of the ultrasonic vibrator provided in the bonding tool change due to the temperature rise due to heating, and it is difficult to give stable ultrasonic vibration. In order to prevent the thermal effect on the ultrasonic transducer, a heat insulating mechanism and a cooling mechanism must be additionally provided in the bonding tool, which complicates the structure of the bonding tool and hinders its compactness. It was.

Further, when the substrate is heated in order to avoid the above-mentioned problems, a problem at the time of ultrasonic bonding due to the softening of the substrate due to the temperature rise is inevitable depending on the material of the substrate. That is, in bonding using ultrasonic waves, the contact surface is slightly slid by ultrasonic vibration while the bumps of the electronic component are in contact with the electrodes of the substrate.

At this time, when the substrate is made of a material such as a resin material which is softened by a temperature rise, the applied ultrasonic vibration is easily absorbed by the expansion and contraction of the softened substrate. As a result, ultrasonic vibration does not effectively act on the contact surface between the bump and the electrode, the bonding efficiency is reduced, and it is difficult to secure the bonding quality. As described above, the conventional bonding apparatus for electronic components has a problem that it is difficult to perform efficient bonding with good bonding quality due to the heating method of the electronic components and the substrate.

Therefore, an object of the present invention is to provide a bonding apparatus and a bonding method for an electronic component, which can prevent the deterioration of the bonding efficiency and ensure the bonding quality.

[0008]

According to a first aspect of the present invention, there is provided an electronic component bonding apparatus for bonding an electronic component by pressing the electronic component against a substrate by a bonding head to apply ultrasonic vibration. An apparatus, a substrate mounting portion on which the substrate is mounted, a bonding tool provided on the bonding head for contacting and pressing the electronic component, and a vibration applying unit for applying ultrasonic vibration to the bonding tool. And a component heating means that is provided separately from the bonding tool and that heats the electronic component prior to mounting the electronic component on the substrate.

According to a second aspect of the present invention, there is provided an electronic component bonding apparatus according to the first aspect, wherein the component heating means heats the electronic component held by the bonding tool from below.

An electronic component bonding apparatus according to a third aspect of the present invention is the electronic component bonding apparatus according to the first aspect, wherein the substrate is a resin substrate and the substrate mounting portion is a resin substrate on which the substrate is mounted. A substrate heating means for heating the resin substrate at a temperature not higher than the glass transition temperature was provided.

According to a fourth aspect of the present invention, there is provided an electronic component bonding method for bonding an electronic component by pressing the electronic component against a substrate by a bonding head and applying ultrasonic vibrations to the substrate. A substrate placing step of placing the substrate on the substrate placing part,
A component heating step of heating the electronic component prior to mounting the electronic component on the substrate, pressing the heated electronic component against the substrate by the bonding tool provided in the bonding head, and applying ultrasonic vibration to the bonding tool. And a bonding step of bonding and bonding the electronic component to the substrate.

According to a fifth aspect of the present invention, there is provided an electronic component bonding method according to the fourth aspect, wherein in the component heating step, the electronic component held by the bonding tool is heated from below.

An electronic component bonding method according to a sixth aspect of the present invention is the electronic component bonding method according to the fourth aspect, wherein the substrate is a resin substrate, and the resin substrate is provided on the substrate mounting portion. The heating means heats the resin substrate at a temperature not higher than the glass transition temperature.

According to the present invention, the electronic component is provided with a component heating means for heating the electronic component prior to mounting the electronic component on the substrate, and the joint surface of the electronic component is preheated so that the substrate is not softened by heating. It is possible to raise the temperature of the bonding surface to efficiently perform ultrasonic bonding and to secure the bonding quality.

[0015]

(First Embodiment) FIG. 1 is a side view of an electronic component bonding apparatus according to a first embodiment of the present invention.
2 is a partial front view of the electronic component bonding apparatus according to the first embodiment of the present invention, FIG. 3 is an explanatory view of a component heating means of the electronic component bonding apparatus according to the first embodiment of the present invention, FIGS. FIG. 4 is a process explanatory view of the electronic component bonding method according to the first embodiment of the present invention.

First, the structure of a bonding apparatus for electronic components will be described with reference to FIGS. In FIG.
A board positioning portion 2a is provided on the XY table 1. The substrate positioning unit 2 a includes a bonding stage 3 (substrate mounting unit) arranged on the XY table 1, and a substrate 4 is mounted on the bonding stage 3. The bonding stage 3 has a built-in heater 3a (substrate heating means) having a temperature adjusting function.
The substrate 4 placed on the upper surface can be heated by operating the.

The substrate 4 is a resin substrate made of a resin such as an epoxy resin, a polyimide resin, an acrylic resin, or polyethylene terephthalate. When the substrate 3 is heated by the heater 3a, the set temperature of the heater 3a is adjusted by the temperature adjusting function so that the substrate 4 is heated at a heating temperature equal to or lower than the glass transition temperature of the resin material of the substrate 4. An electrode 4a for mounting electronic components is provided on the upper surface of the substrate 4, and a gold film is formed on the surface of the electrode 4a. By heating the substrate 4 at the above-mentioned set temperature by the heater 3a during bonding, the temperature of the electrode 4a can be raised within a range in which the resin material of the substrate 4 is not softened.

As shown in FIG. 2, a component supply unit 2b is provided on the side of the substrate positioning unit 2a on the XY table 1, and an electronic component 9 to be bonded is stored on the component supply unit 2b. ing. By driving the XY table 1, the board positioning portion 2a and the component supply portion 2b can be horizontally moved relative to the bonding portion 5 described below. A gold electrode 9a for connection is formed on the lower surface of the electronic component 9, and the electronic component 9 is mounted on the substrate 4 by bonding the gold electrode 9a to the electrode 4a of the substrate 4.

In FIG. 1, a bonding portion 5 is arranged above the substrate positioning portion 2a. The bonding unit 5 includes a bonding head 7 that is lifted and lowered by a head lifting mechanism 6, and a bonding tool 8 (hereinafter simply referred to as “tool 8”) is provided at a lower end portion of the bonding head 7.
And abbreviated. ) Is installed. As shown in FIG.
Is equipped with an elongated horizontal horn 8a.
On the lower surface of a, the joining action portion 8b is provided so as to project downward.

A suction hole (not shown) is provided on the lower surface of the joining action portion 8b, and the joining action portion 8b is brought into contact with the upper surface of the electronic component 9 and vacuum suction is performed from this suction hole, whereby the electronic component 9 is adsorbed and retained. A vibrator 8c (vibration imparting means) is attached to one end of the horn 8a. By driving the vibrator 8c, ultrasonic vibration is applied to the electronic component 9 via the horn 8a and the joining action portion 8b.

In the bonding operation, the electronic component 9
The substrate positioning portion 2a is provided below the horn 8a that sucks and holds
To move. Then, the head elevating mechanism 6 is driven to lower the bonding head 7 with respect to the substrate 4 on the substrate positioning portion 2a, and the gold electrode 9a of the electronic component 9 is aligned with the electrode 4a of the substrate 4 and pressed. At this time, the vibrator 8c
Is driven to apply ultrasonic vibration to the electronic component 9. As a result, the electronic component 9 is bonded to the substrate 4 by the pressing load and ultrasonic vibration.

In the space between the bonding head 7 and the bonding stage 3, a vertical observation optical device 10 capable of simultaneously performing observations in both vertical directions is provided. The vertical observation optical device 10 is arranged so as to be able to move forward and backward in the horizontal direction by an advance / retreat mechanism 11.
By entering 0 between the bonding head 7 and the bonding stage 3, the substrate 4 on the bonding stage 3 and the electronic component 9 held by the bonding head 7 can be observed at the same time.

In FIG. 1, an infrared irradiation lamp 18 as a component heating means is arranged on the front side (left side in FIG. 1) of the bonding portion 5. The infrared irradiation lamp 18 can be horizontally moved by the moving table 17, and when the infrared irradiation lamp 18 is moved to the bonding portion 5 side, the infrared irradiation lamp 18 is connected to the bonding action part of the tool 8 as shown in FIG. It is located below the electronic component 9 held by 8b.

By turning on the infrared irradiation lamp 18 in this state, infrared rays are irradiated to the lower surface side (electrode formation surface side) of the electronic component 9. The lower surface side of the electronic component 9 is heated by the radiant heat of infrared rays, and the temperature of the gold electrode 9a rises. As a heating source of the component heating means, various heating methods such as an infrared irradiation lamp, a ceramic heater which similarly generates infrared rays, and a method of raising the temperature of the electronic component 9 by electromagnetic induction heating can be used.

Next, the control system of the bonding apparatus will be described. The control unit 14 controls the operations of the head lifting mechanism 6, the XY table 1, and the moving table 17. Thereby, the bonding operation by the bonding head 7,
Prior to the bonding operation, operation control of the infrared irradiation lamp 18 at the time of heating the electronic component 9 is performed. The imaging data of the up-down observation optical device 10 is sent to the recognition unit 13, and the recognition unit 13 performs recognition processing on these imaging data, whereby the electronic component 9 held by the bonding head 7 and the substrate 4 on the bonding stage 3 are held. The position is detected. The gold electrode 9a of the electronic component 9 and the electrode 4a of the substrate 4 described above.
The position of the control unit 1 is adjusted based on the position detection result.
4 is performed by controlling the above-mentioned units.

The control unit 14 is connected to the display unit 15 and the operation / input unit 16. The operation / input unit 16 inputs various data and operation commands for operation commands. The display unit 15 displays the guide screen at the time of the above-mentioned operation input, and also displays the screen imaged by the vertical observation optical device 10.

This electronic component bonding apparatus is constructed as described above. Next, the bonding method will be described with reference to FIGS. 4 and 5. First, in FIG. 4A, the substrate 4 to be bonded is placed on the bonding stage 3 (substrate placing step). Then, the heater 3a is operated to heat the substrate 4 at a heating temperature equal to or lower than the glass transition temperature of the resin material of the substrate. As a result, the temperature of the electrode 4a on the substrate 4 rises.

Next, as shown in FIG. 4B, the component supply unit 2b is positioned below the tool 8 of the bonding head 7, and the head elevating mechanism 6 is driven to move the tool 8 to an electronic component on the component supply unit 2b. Raise and lower with respect to 9. As a result, as shown in FIG. 4C, the joining action portion 8 of the tool 8 is
The electronic component 9 is held by b by vacuum suction. Then, in this state, the vertical observation optical device 10 is advanced below the tool 8 to image the electronic component 9 and the substrate 4, and the recognition unit 13 performs recognition processing on the imaging data,
The positions of the electronic component 9 and the board 4 are detected.

Thereafter, the mounting operation is started. First, before mounting the electronic component 9 on the substrate 4, the moving table 17 is driven to drive the infrared irradiation lamp 1 as shown in FIG.
8 is positioned below the electronic component 9 held by the tool 8, the infrared irradiation lamp 18 is turned on, and the lower surface side of the electronic component 9 is heated by infrared rays (component heating step). Thereby, the gold electrode 9a of the electronic component 9 is heated to a predetermined heating temperature. The heating temperature at this time is the same as that of the electronic component 9 and the substrate 4.
The temperature is set between 100 ° C. and 300 ° C. according to the combination of types. In this component heating step, since the gold electrode 9a, which is the bonding portion in the ultrasonic bonding, is heated from the closest lower position, it is possible to raise the temperature of the bonding portion intensively and efficiently.

Then, the bonding head 7 is lowered, and the XY table 1 is driven to horizontally move the substrate 4 to move the tool 8 as shown in FIG. 5 (b).
The gold electrode 9a of the electronic component 9 and the electrode 4 of the substrate 4 held by the
The position a is aligned with the position detection result obtained by the recognition shown in FIG.

Then, as shown in FIG. 5C, the tool 8
By pressing the electronic component 9 against the substrate 4 by means of the gold electrode 9a is pressed against the electrode 4a with a predetermined bonding load, the vibrator 8c is driven to bond the bonding action portion 8
Ultrasonic vibration is applied to the electronic component 9 via b. As a result, the electronic component 9 is bonded by the gold electrode 9a being diffusion bonded to the gold film formed on the surface of the electrode 4a (bonding step), and the mounting of the electronic component 9 on the substrate 4 is completed.

In this ultrasonic joining, the gold electrode 9a to be joined is connected by the infrared irradiation lamp 18 and the electrode 4
Since a is preheated by the heater 3a, and these heatings are performed immediately before the components are mounted on the substrate 4, the temperature drop is small, so that the bonding temperature in the ultrasonic bonding process can be kept as high as possible. Has become. As a result, it is possible to soften the bonding surface portion of the gold electrode 9a and the electrode 4a to increase the area of the bonding interface, and promote metal diffusion in the bonding process to obtain good bonding quality.

At this time, when the substrate 4 is heated, the heating temperature is set so as to be equal to or lower than the glass transition temperature of the resin material, so that the substrate 4 is excessively heated and the substrate body is softened. do not do. As a result, the softened substrate 4 around the joint absorbs ultrasonic vibrations, and the vibration action loss is small, and the ultrasonic vibrations transmitted to the electronic component 9 are effectively applied to the joints of the gold electrode 9a and the electrode 4a. Can be applied to perform efficient bonding.

Further, since the component heating means for preheating the electronic component 9 is provided separately from the tool 8, the temperature of the tool 8 does not rise due to this component heating. Therefore, it is possible to prevent a change in the vibration characteristic due to the temperature rise of the vibrator 8c, and it is possible to apply stable vibration. Therefore, it is not necessary to provide a heat insulating mechanism or a cooling mechanism which is required in the conventional bonding tool having a built-in component heating means, and a bonding tool having a simple structure and a compact structure can be realized.

In the first embodiment described above, the example of the substrate 4 is the resin substrate which is easily softened by the temperature rise and the effect of the present invention is remarkable, but the present invention is applied to the resin substrate. Of course, it is not limited to. In addition, the substrate 4 that is performed prior to bonding
The heating is not always necessary, and the above-described effect can be obtained only by heating the electronic component 9.

Further, in the above-described first embodiment, an example in which the gold electrode 9a is bonded to the electrode 4a having a gold film on the surface as a combination of the materials of the bonding portion is shown. However, the metal surfaces are pressed against each other to diffuse the metal. A metal material other than gold may be used for the joint portion as long as it is a combination that can be joined by.

(Embodiment 2) FIG. 6 is a partial front view of a bonding apparatus for electronic parts according to Embodiment 2 of the present invention, and FIG.
Is an operation explanatory view of the electronic component bonding apparatus according to the second embodiment of the present invention, and FIG. 8 is a partial front view of the electronic component bonding apparatus according to the second embodiment of the present invention.

In FIG. 6, a board positioning portion 2a and a component supply portion 2b similar to those shown in the first embodiment are arranged on the XY table 1, and the board positioning portion 2a and the component supply portion 2b are arranged. A component heating stage 19 having a heater 19a built therein is arranged in between. XY table 1
Any of the substrate positioning portion 2a, the component heating stage 19 or the component supply portion 2b can be positioned below the bonding head 7 by driving the.

As shown in FIG. 7A, the component heating stage 19 whose upper surface is heated by the heater 19a.
Then, the electronic component 9 taken out from the component supply unit 2b by the tool 8 is placed thereon, and the gold electrode 9a on the lower surface of the electronic component 9 is brought into contact with the component heating stage 19 so that the gold electrode 9
A is heated by heat transfer from the upper surface of the component heating stage 19. That is, here, the component heating stage 19 serves as a component heating means.

After the gold electrode 9a is pressed against the component heating stage 19 for a predetermined time, the tool 8 is raised to move the XY table 1 and, as shown in FIG. 7 (b),
The substrate 4 on the bonding stage 3 is aligned with the tool 8 holding the electronic component 9. Then, as in the first embodiment, the gold electrode 9a is pressed against the electrode 4a on the substrate, the vibrator 8c is driven, and ultrasonic vibration is applied to the electronic component 9. As a result, the electronic component 9 is bonded to the substrate 4.

Also in the second embodiment, since the gold electrode 9a is heated prior to mounting the electronic component 9 on the substrate 4, as in the example shown in the first embodiment, the securing of the bonding quality and the bonding are ensured. Improved efficiency is realized.

The component heating stage 19 is used as shown in FIG. 8, that is, the component supply unit 2b 'is arranged separately from the XY stage 1, and the transfer head 2 is used.
The electronic component 9 may be taken out from the component supply unit 2b ′ by 0 and placed on the component heating stage 19.
In this configuration, the electronic component 9 heated by the component heating stage 19 for a predetermined time is held by the tool 8 and bonded to the substrate 4.

[0043]

According to the present invention, there is provided a component heating means for heating an electronic component prior to mounting the electronic component on the substrate,
Since the joint surface of the electronic component is preheated, it is possible to raise the temperature of the joint surface without causing softening due to heating of the substrate, perform ultrasonic bonding efficiently, and ensure the joint quality.

[Brief description of drawings]

FIG. 1 is a side view of an electronic component bonding apparatus according to a first embodiment of the present invention.

FIG. 2 is a partial front view of the electronic component bonding apparatus according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of component heating means of the electronic component bonding apparatus according to the first embodiment of the present invention.

FIG. 4 is a process explanatory diagram of a bonding method for an electronic component according to the first embodiment of the present invention.

FIG. 5 is a process explanatory diagram of a bonding method for an electronic component according to the first embodiment of the present invention.

FIG. 6 is a partial front view of an electronic component bonding apparatus according to a second embodiment of the present invention.

FIG. 7 is an operation explanatory diagram of the electronic component bonding apparatus according to the second embodiment of the present invention.

FIG. 8 is a partial front view of an electronic component bonding apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

3 Bonding stage 4 substrates 4a electrode 5 Bonding section 7 Bonding head 8 Bonding tool (tool) 9 electronic components 9a Gold electrode 18 Infrared irradiation lamp

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5E319 AA03 AB05 AC01 CC12 CC60                       CD04 CD31 GG11 GG15                 5F044 KK02 PP16 PP19

Claims (6)

[Claims] 1. A bonding apparatus for an electronic component, which bonds an electronic component by pressing the electronic component against the substrate by a bonding head and applying ultrasonic vibrations to the substrate. A bonding tool provided on the bonding head for contacting and pressing the electronic component; a vibration applying unit for applying ultrasonic vibration to the bonding tool; and a substrate for the electronic component provided separately from the bonding tool. An electronic component bonding apparatus comprising: a component heating means for heating the electronic component prior to mounting on the electronic component. 2. The electronic component bonding apparatus according to claim 1, wherein the component heating means heats the electronic component held by the bonding tool from below. 3. The substrate is a resin substrate, and the substrate mounting part is provided with a substrate heating means for heating the mounted resin substrate at a heating temperature equal to or lower than the glass transition temperature of the resin substrate. An electronic component bonding apparatus according to claim 1. 4. A method of bonding an electronic component by pressing the electronic component against the substrate with a bonding head to apply ultrasonic vibrations, the method comprising: mounting the substrate on a substrate mounting portion. Substrate placing step, component heating step of heating the electronic component prior to mounting the electronic component on the substrate, and pressing the heated electronic component against the substrate by a bonding tool provided in the bonding head and bonding. A bonding step of applying ultrasonic vibration to the tool to bond the electronic component to the substrate. 5. The method of bonding an electronic component according to claim 4, wherein in the component heating step, the electronic component held by the bonding tool is heated from below. 6. The substrate is a resin substrate, and the resin substrate is heated at a heating temperature equal to or lower than the glass transition temperature of the resin substrate by a heating means provided in the substrate mounting portion. Bonding method for the described electronic component.