JPH11121531A - Mounting of electronic component and mounting device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heat only the connection parts of an electronic component with substrate pads, also in the case where the connection parts of the component with the pads are arranged at narrow pitches by a method wherein heating light is made to be irradiated on positions, where gold bumps are placed on the substrate pads, from light sources via a mask to enable the light to pass via a desired region only. SOLUTION: A heater 3 provided in an electronic component suction-heating unit 1 is used to heat metal bumps 11, and at the same time, a pressure is applied to an electronic component 10 from over the component 10. At the some time, light for enabling the temperature of the metal bumps 11 to rise is irradiated from light sources 9, and the contact parts of the bumps 11 with substrate pads 21 are heated with light, which is passed through a mask open parts 5 formed in the mask 4. In this way, since the light is used as a heat feed source, the contact parts only of the bumps 11 with the pads 21 can be reliably heated though the pitch between the bumps 11 regardless of whether the pads 21 is narrow or not. Moreover, as the irradiation positions of the heating light are decided by the opening parts 5 formed in the mask 4, a mounting device can also correspond fully to the minute arrangement of the connection part of the component 10 with a substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting method and a mounting apparatus for an electronic component, and more particularly, to a method for heating a connection portion between an electronic component and a substrate to thereby obtain a difference in thermal expansion between the electronic component and the substrate. TECHNICAL FIELD The present invention relates to a mounting method and a mounting apparatus for an electronic component, which can prevent a displacement of a connection portion due to the above.

[0002]

2. Description of the Related Art In recent years, attention has been paid to an arrangement in which metal bumps are arranged in a grid on the back surface of an electronic component and the metal bumps are used as electrodes. Such electronic components include:
For example, BGA (Ball Grid Array), CSP (Chip Scale Package), or a flip chip is used.

[0003] In the electronic parts having the above-mentioned metal bumps, since the electrodes made of the metal bumps are arranged at a narrow pitch, they are reflowed simultaneously with other general surface mount parts such as chip capacitors and chip coils. Is difficult to do. Therefore, electronic components having such electrodes are individually mounted separately from other general surface mount components.

In the individual mounting as described above, when mounting an electronic component, heat is applied while pressing the electronic component from above, and the metal bumps provided on the electronic component are heated and provided on the substrate side. Fused to the pad.

At this time, heat is also applied from the substrate side in order to prevent heat from escaping from the pads provided on the substrate side.

[0006]

However, when heat is applied to the substrate as described above, the substrate may be a printed substrate made of glass epoxy or a flexible substrate having a wiring pattern formed on an insulating film. In this case, the coefficient of thermal expansion of the substrate is larger than the coefficient of thermal expansion of the electronic component.

As a result, a gap occurs between the pitch of the electrodes provided on the electronic component and the pitch of the pads provided on the substrate,
This was causing poor connection. Also, even if the electrodes of the electronic component are normally connected to the pads of the board by the heating method described above, the board side shrinks greatly in the cooling process of stopping the supply of heat and returning the mounted body to normal temperature. There was a problem that a crack was generated in the portion or the portion was broken.

Japanese Patent Application Laid-Open No. 7-313377 discloses a means for solving the above problem, in which a rod-like heating element for locally heating a pad of a substrate is brought into contact with the vicinity of the pad to minimize the heat applied to the substrate. A suppression technique is disclosed.

However, in the technology described in the above publication,
When the electrodes of the electronic component have a narrow pitch, it is difficult to secure a space where the heating element is in contact with the pad, so that it is difficult to implement the heating element. Further, in the above technique, since the pad is heated by a mechanical method, it is necessary to increase the accuracy of the mechanism for moving the heating element.

As described above, according to the above technique, when the substrate is warped, when the precision of the mechanism is low, or when the shape of the heating body is large, the peripheral portion of the pad is also substantially heated. However, there is a problem that thermal expansion of the portion cannot be avoided.

Accordingly, the present invention provides a mounting method and a mounting apparatus for an electronic component that can heat only the connection portion even when the connection portions between the electronic component and the substrate are arranged at a narrow pitch. The purpose is to provide.

[0012]

In order to achieve the above-mentioned object, the invention according to claim 1 is directed to a first embodiment formed on an electronic component.
Contacting the first connection terminal with a second connection terminal formed at a position corresponding to the first connection terminal on the substrate; and supplying heat to the electronic component to form the first connection terminal. A first heating step of heating, and a second heating step of locally irradiating at least one of the first connection terminal and the second connection terminal with light and heating the irradiated portion. And

According to a second aspect of the present invention, in the first aspect of the invention, the second heating step includes a step of forming a mask having an opening corresponding to the size of a portion to be irradiated with light. The method includes a mask positioning step of positioning a portion to be irradiated, and a step of irradiating light to the mask positioned in the mask positioning step.

According to a third aspect of the present invention, in the first or second aspect, the electronic component has a different coefficient of thermal expansion from the substrate.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the electronic component is a surface mount type component.

According to a fifth aspect of the present invention, the first connection terminal formed on the electronic component is brought into contact with the second connection terminal formed on the substrate at a position corresponding to the first connection terminal. Contacting means, a first heating means for heating the first connection terminal by supplying heat to the electronic component, and a local heating means for at least one of the first connection terminal and the second connection terminal. To irradiate light and heat the irradiated part
And heating means.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the second heating means includes a mask having an opening corresponding to the size of a portion to be irradiated with light. It is characterized by comprising mask positioning means for positioning with respect to a portion to be irradiated, and means for irradiating light to the mask positioned in the mask positioning step.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the second heating means includes a deflecting means for changing an irradiation direction of the light passing through the opening of the mask. It is characterized by.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a method and an apparatus for mounting an electronic component according to the present invention will be described in detail with reference to the accompanying drawings.

First, an outline of the present invention will be described with reference to FIG. FIG. 1 is a side view showing the structure of the electronic component mounting apparatus according to the present invention.

According to the present invention, as shown in FIG.
A light source 9 that generates heating light for heating the metal bumps 11 disposed on the metal bumper 11 and a mask 4 that allows light generated by the light source 9 to pass through only a desired region are provided. By irradiating the position where the bump 11 is placed on the substrate pad 21 with heating light, even if the connection parts between the electronic component and the substrate are arranged at a narrow pitch, only the connection part is heated. It is an object of the present invention to provide a mounting method and a mounting device for an electronic component that can be used.

Hereinafter, the contents of the present invention will be described in more detail.

As shown in FIG. 1, the electronic component mounting apparatus according to the present invention includes an electronic component suction heating device 1 for attracting and heating an electronic component 10, a board heating device 2 for heating a printed board 20, and an electronic component mounting device. A heater 3 serving as a heat source of the adsorption heating device 1, a mask 4 for blocking unnecessary heating light, a mask opening 5 for passing necessary heating light, a light source 9 for generating heating light, and a mask 4 It comprises a vertically movable mask holding portion 8, a vertically movable light source holding portion 7 for holding the light source 9, and a support 6 serving as a support for the mask holding portion 8 and the light source holding portion 7. Works like

The electronic component suction and heating device 1 has a suction portion on its bottom surface and detachably suctions electronic components. The electronic component adsorption and heating device 1 can move freely up, down, left and right,
When placing electronic components on a printed circuit board, positioning is performed while moving in the left and right direction.
The metal bump 11 is moved downward to bring the metal bump 11 into contact with the substrate pad 21.

The electronic component suction and heating device 1 has a built-in heater 3 which is used to fuse the metal bumps 11 through the electronic component package when the metal bumps are fused.
Supply heat to In addition, at the time of this heating, it acts so as to apply pressure from above to the electronic component.

The substrate heating device 2 acts as a support for the printed circuit board and acts so as to hold down the pressure of the electronic component suction / heating device 1.

The mask holding section 8 holds the mask 4 from both ends, and moves up and down to position the mask. This positioning is performed in consideration of the shape of the mask opening 5, the irradiation direction of the heating light generated by the light source 9, and the position of the substrate pad 21.

The light source holder 7 holds the light source 9 from both ends, and moves up and down to determine the irradiation direction of the heating light generated by the light source 9.

Next, the structure of the mask 4 used in the electronic component mounting apparatus according to the present invention will be described with reference to FIG.

FIG. 2 is a top view showing the structure of the mask 4 shown in FIG. As shown in the figure, the mask 4 has a shape surrounding the periphery of the electronic component suction and heating device 1.
An escape is provided between the electronic component suction and heating device 1 and is configured to be able to move up and down freely. The mask 4
The mask openings 5 corresponding to the positions of the substrate pads 21 arranged on the printed circuit board 20 are formed, and only the openings allow the heating light to pass therethrough.

At this time, it is preferable that the heating light generated by the light source 9 is applied to the light irradiation area 4a shown in FIG. Therefore, the structure of the light source 9 is
The shape corresponding to a is good. When the light source 9 having such a shape cannot be used, an individual light source may be provided for each mask opening 5, or one light source may be sequentially moved for each mask opening 5, Pad 2
1 may be heated in order.

The shape of the mask opening 5 is preferably as small as possible as long as a predetermined temperature rise can be obtained because the smaller the opening, the more locally the substrate pad 21 can be heated. . Further, as shown in FIG. 1, the cross-sectional shape is preferably formed obliquely in the direction from the light source 9 to the substrate pad 21.

Next, the structures of the electronic component 10 and the printed circuit board 20 to be mounted by the electronic component mounting apparatus according to the present invention will be briefly described.

According to the present invention, a metal bump 11 such as a solder bump is provided.
Is particularly effective for mounting electronic components such as flip chips and chip size packages arranged at a narrow pitch on the bottom surface of the electronic component 10. Although only two metal bumps 11 are shown in FIG. 1 for simplicity of illustration, the present invention can be applied to an electronic component provided with a large number of metal bumps 11.

The metal bumps 11 are not limited to solder bumps. The present invention is not limited to solder bumps, but may be made of a metal having a high melting point, such as gold, silver or copper, as long as it is electrically connected by heat. Can be applied. Metal bump 1
The present invention is also applicable to a case where a current-carrying member such as solder is supplied without melting itself.

On the other hand, the printed circuit board 20 has a wiring pattern 22 formed on the surface thereof.
2 is covered with a solder resist 23. Here, the substrate pad 21 may be a portion in which a part of the wiring pattern 22 is exposed by covering the solder resist 23 as shown in FIG. 1 or a terminal for connecting an electronic component is provided. It may be something. Further, the present invention can be applied to a metal substrate other than a printed circuit board, a ceramic substrate, and the like.

Next, an example in which an electronic component is mounted using the electronic component mounting apparatus configured as described above will be described with reference to FIG.

FIG. 3 is a side view showing a state in which the connection between the electronic component and the printed circuit board is heated by the electronic component mounting apparatus shown in FIG. As shown in FIG. 1, the electronic component mounting apparatus first sucks the electronic component 10 on the bottom surface of the electronic component suction and heating device 1 and mounts the electronic component 10 at a predetermined position on the printed circuit board 20.

Thereafter, the mask holder 8 and the light source 9 are moved up and down to position the mask 4 and the light source 9.

Next, the metal bumps 11 are heated using the heater 3 provided in the electronic component suction and heating device 1, and pressure is applied to the electronic component 10 from above. At the same time, light that can raise the temperature of the metal, such as infrared light or laser, is emitted from the light source 9, and the light passing through the mask opening 5 heats the contact portion between the metal bump 11 and the substrate pad 21. Since the heating by the heating light is preliminary for preventing the heat from the electronic component suction heating device 1 from escaping to the substrate, the heating by the heating light is performed at a temperature lower than the temperature of the heat supplied by the electronic component suction heating device 1. Set a little lower.

The heating by the heating light may be performed before the metal bump 11 and the substrate pad are brought into contact with each other. In this case, the heating light is applied to the substrate pad for a predetermined time, and then the electronic component is attracted. What is necessary is just to make a heating apparatus act. If heating is performed in this order, even if the metal bumps are arranged in a grid, there is nothing to block the irradiation of the heating light, so that all the substrate pads can be heated.

In addition, even with the configuration shown in FIG. 3, only the substrate pad 21 may be irradiated with heating light to heat the substrate pad 21 or only the metal bump 11 may be irradiated with heating light. Alternatively, only the metal bumps 11 may be heated.

As described above, in the present invention, since light is used as a heat supply source, it is possible to reliably heat only the contact portions between the metal bumps 11 and the substrate pads 21 regardless of whether the pitch is narrow or not. it can.

Further, since the irradiation position of the heating light is determined by the opening formed in the mask 4, it can be sufficiently applied to a fine arrangement.

Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 4 is a side view showing a second embodiment of the electronic component mounting apparatus according to the present invention. In the second embodiment, as shown in the figure, heating light is irradiated vertically from above the mask 4 and the path of the heating light is changed by the deflector 30 provided in the mask holding unit 8.

The deflector 30 is made of a material such as a mirror that reflects light. The deflector 30 may be attached to the mask 4 or may be formed in the mask opening 5.

As described above, by providing the deflector, the degree of freedom of irradiation is increased, and it is possible to cope with electronic components having a narrower pitch.

The present invention can be applied to leadless components such as a small outline non-leaded package and a quad flat non-leaded package which do not have a thermal stress relaxing action.

[0050]

As described above, according to the present invention,
It is possible to provide a mounting method and a mounting apparatus for an electronic component that can heat only the connection portion even when the connection portions between the electronic component and the substrate are arranged at a narrow pitch.

In the present invention, since light is used as a heat source, regardless of whether the pitch is narrow or not.
Only the contact portion between the metal bump 11 and the substrate pad 21 can be reliably heated.

Further, since the irradiation position of the heating light is determined by the opening formed in the mask 4, it can be sufficiently applied to a fine arrangement.

Further, by providing a deflector, the degree of freedom of irradiation is increased, and it is possible to cope with electronic components having a narrower pitch.

[Brief description of the drawings]

FIG. 1 is a side view showing the structure of an electronic component mounting apparatus according to the present invention.

FIG. 2 is a top view showing the structure of a mask 4 shown in FIG.

FIG. 3 is a side view showing a state in which the connection between the electronic component and the printed board is heated by the electronic component mounting apparatus shown in FIG. 1;

FIG. 4 is a side view showing a second embodiment of the electronic component mounting apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electronic component adsorption | suction heating apparatus, 2 ... Substrate heating apparatus, 3 ... Heater, 4 ... Mask, 4a ... Light irradiation area, 5 ... Mask opening part, 6 ... Prop, 7 ... Light source holding part, 8 ... Mask holding part,
9 ... light source, 10 ... electronic parts, 11 ... metal bumps, 20 ...
Printed circuit board, 21: board pad, 22: wiring pattern, 23: solder resist, 30: deflector.

Claims (7)

[Claims] A step of bringing a first connection terminal formed on an electronic component into contact with a second connection terminal formed on a substrate at a position corresponding to the first connection terminal; A first heating step of heating the first connection terminal by supplying heat, and locally irradiating light to at least one of the first connection terminal and the second connection terminal, And a second heating step of heating. 2. The second heating step includes: a mask positioning step of positioning a mask having an opening corresponding to a size of a part to be irradiated with light with respect to the part to be irradiated with light; Irradiating the mask positioned by the step with light.
The mounting method of the described electronic component. 3. The electronic component mounting method according to claim 1, wherein the electronic component has a different coefficient of thermal expansion from the substrate. 4. The electronic component mounting method according to claim 1, wherein the electronic component is a surface mount type component. 5. A contact means for bringing a first connection terminal formed on an electronic component into contact with a second connection terminal formed on a substrate at a position corresponding to the first connection terminal, and the electronic component. A first heating means for heating the first connection terminal by supplying heat to the first connection terminal; and irradiating at least one of the first connection terminal and the second connection terminal with light locally. And a second heating means for heating the electronic component. 6. The mask positioning means for positioning a mask having an opening corresponding to the size of a part to be irradiated with light with respect to the part to be irradiated with light, the second heating means comprising: 6. The electronic component mounting apparatus according to claim 5, further comprising: means for irradiating light to the mask positioned in the step. 7. The electronic component mounting apparatus according to claim 6, wherein said second heating means includes a deflecting means for changing an irradiation direction of light passing through the opening of said mask.