JP3211325B2 - An electronic component manufacturing method and apparatus, and a mounting method. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to an electronic component such as a C chip, a method of manufacturing the same, a method of mounting the same, and a device for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, as a method for mounting an IC chip on a substrate, a CO that is face-down mounted on an electrode on the substrate has been used.
B (CHIP ON BOARD) implementation is receiving attention.

As a conventional COB mounting technique, a creamy solder is formed on electrodes on a substrate by a printing method, and an IC chip is mounted face-down on the printed solder.

An example of the above-mentioned conventional COB mounting technology will be described below with reference to the drawings. 5 and 6
Shows a method of mounting an IC chip on a substrate. 5 and 6, 1 is a substrate, 2 is an electrode on the substrate, 3 is an IC chip, 4 is an aluminum electrode, 5 is a gold bump, 1
6 is a cream solder, 17 is a squeegee, and 18 is a screen mask.

[0005] The operation of the mounting method on the substrate configured as described above will be described below.

FIG. 5 is a view showing a method for forming solder on the electrode 2 on the substrate. A screen mask 18 having an opening corresponding to the electrode 2 on the substrate is positioned on the substrate 1 and then superposed, and the cream solder 16 is moved by using a squeegee 17 on the screen mask 18 so that the opening has a cream. The solder 16 remains, and the cream mask 16 is formed on the electrode 2 on the substrate by removing the screen mask 18.

[0007]

In order to achieve the above object, the present invention provides an IC chip, an aluminum electrode formed on the IC chip, and gold bumps and solder bumps sequentially laminated on the aluminum electrode. As a method for forming a solder bump having the following characteristics, while supplying an oxygen-preventing gas, solder is supplied by a wire bonding method, and the solder bump is irradiated with light to increase the bonding strength by heating and melting. ing.

[0008]

However, in the above-described conventional structure, when the interval between the aluminum electrodes of the IC chip becomes narrow, it is difficult to form the opening of the screen mask, and at the same time, a small amount of cream solder is printed. It is difficult, and the yield of bonding decreases.

In the case where the electrical connection failure is redone after the solder is melted, the redo method is to melt the solder, remove the IC chip, and mount a new IC chip. However, many electronic components are soldered on the substrate. In such a case, it is impossible to superimpose the screen mask on the substrate, so that it is impossible to supply new solder by printing.

The present invention solves the above-mentioned problems, and enables a stable supply of solder even when the distance between the electrodes is reduced.
It is an object of the present invention to provide an electronic component which does not need to supply solder onto a substrate even in the case of re-mounting, and a method of manufacturing the same.

[0011]

In order to achieve the above object, the present invention provides an IC chip, an aluminum electrode formed on the IC chip, and gold bumps and solder bumps sequentially laminated on the aluminum electrode. And a configuration having: In the method of forming solder bumps, solder is supplied by a wire bonding method while supplying an antioxidant gas, and the solder bumps are irradiated with light to increase the bonding strength by heating and melting.

[0012]

According to the above configuration, stable solder supply and solder bump formation can be achieved even when the electrodes on the IC chip are at a narrow interval, and it is not necessary to supply solder on the substrate to form solder bumps on the IC chip. This eliminates the need to create a metal mask for printing, and eliminates the need to resupply the solder on the substrate in the case of re-mounting.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An IC chip 3 according to an embodiment of the present invention will be described below.
The supply of solder to the upper side will be described with reference to the drawings.

FIG. 1 is a diagram showing a process of mounting an IC chip 3 supplied with solder on a substrate 1 in a first embodiment of the present invention. In FIG. 1, reference numeral 6 denotes a solder bump, and 7 denotes a flux.

FIGS. 2 to 4 show a method of supplying solder and a method of mounting on the IC chip 3 configured as described above.
The operation will be described with reference to FIG.

FIG. 2 shows a process of forming the gold bumps 5 on the IC chip 3; 8 is a suction table; 9 is a capillary;
Is a gold wire. In the process of FIG. 2, the IC chip 3 is attached to a suction table 8 heated to 180 ° C. by a wire bonding apparatus.
Is fixed to the aluminum electrode 4 on the IC chip 3 by using a general wire bonding apparatus, and a gold protrusion is formed by a capillary 9 and a gold wire 10 by a stud bump bonding method.
The gold protrusion is called a gold bump 5. Since the height variation of the gold bumps 5 is about 20 μm, a leveling step of pressing a flat metal from the upper surface to make the heights uniform is performed to keep the height constant.

FIG. 3 shows a process of forming the solder bumps 6 on the gold bumps 5, 11 is a solder wire, 12 is a gas supply device, 13 is a light irradiation device, and 14 is a solder ball. In the process shown in FIG. 3, a capillary is fixed to the suction table 8 heated to 180.degree. C. by vacuum tension in the same manner as in FIG. 9 and the solder wire 11 form a solder protrusion. The solder protrusion is referred to as a solder bump 6. The difference from the wire bonding using the gold wire 10 is that the spark voltage is increased to 2100 volts and the solder balls 14 are formed while supplying a solder oxidation preventing gas of 90% argon + 10% hydrogen.
The method for forming the solder bumps 6 is as follows. A solder ball 14 formed by sparking on the solder wire 11 is pressed and joined onto the gold bump 5, and the solder ball 14 and the solder wire 1
1 is torn off.

Since the bonding strength of the solder bumps 6 on the gold bumps 5 is about 30 grams, they will come off in some form in this state. Also, since the points where the solder balls 14 and the solder wires 11 are torn apart vary, the height variation of the solder bumps is about 40 microns. Therefore, the solder is melted immediately after the formation of the solder bumps 6.

In the solder melting step, as shown in FIG. 3, immediately after the solder bumps 6 are bonded to the gold bumps 5 and cut off, a light irradiating apparatus is supplied while supplying a solder oxidation preventing gas of 90% argon + 10% hydrogen. 13 irradiates light including infrared rays to heat and melt the solder to 230 ° C. The melting of the solder forms an alloy of gold and tin, which increases the bonding strength and does not easily come off.

Further, the solder bump 6 becomes hemispherical by absorbing the torn portion by melting. The amount of the solder bump 6 is substantially equal to the amount of the solder ball 14 because the torn portion is much smaller than the solder ball 14. Also, since the amount of the solder ball 14 depends on the spark voltage, if the spark voltage is constant as in this case,
And the amount of the solder bump 6 is also constant. As described above, since the amount of the solder bump 6 is constant, the height becomes equal in the case of a hemispherical shape after melting. Even in the actual case, the height variation after melting of the solder bump 6 at the spark voltage of 2100 volts was about 3 μm.

By performing the steps shown in FIGS. 2 and 3 as described above, the IC
Solder is supplied onto the chip 3 to manufacture an electronic component that can be mounted.

FIG. 4 is a view showing a step of transferring the flux 7 onto the solder bumps 6, and 15 is a transfer plate. In the process shown in FIG. 4, the paste-like flux 7 containing a solvent is stretched to a certain thickness on the transfer plate 15, and the IC chip 3 is lowered onto the flux 7 as shown in FIG.
Then, the gold bump 5 is immersed in the flux 7. Next, IC
The chip 3 is raised, and the solder bump 6 is separated from the flux 7 on the transfer plate 15. At this time, some flux 7
It is transferred onto the solder bump 6 on the C chip 3.

FIG. 1 is a diagram showing a process of mounting the IC chip 3 onto which the flux 7 has been transferred on the substrate 1. In the process shown in FIG. 1, the IC chip 3 immediately after the transfer of the flux 7 is aligned with the electrode 2 on the substrate 1 and mounted. At this time, the IC chip 3 is held by the viscosity of the flux 7.
After mounting, the entire structure including the substrate 1 is heated to about 230 ° C., and the solder bumps 6 are melted to form an alloy with the electrodes 2 on the substrate. Obtainable. After the completion of the electrical bonding, a resin for stress relaxation and a sealing resin for waterproofing are applied and cured for improving reliability, whereby the mounting of the IC chip 3 on the substrate 1 is completed.

[0024]

As is clear from the above description, the present invention has a structure in which solder bumps are stacked on gold bumps and a structure in which solder is supplied by a wire bonding method.
Solder bumps can be formed at small intervals on the C chip, and there is no need to supply solder on the board. Even if mounting is defective, it can be mounted again simply by replacing the IC chip that has been supplied with solder. An electronic component that can be mounted and a method for manufacturing the electronic component can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an electronic component and a substrate on which the electronic component is mounted according to an embodiment of the present invention.

FIG. 2 is a sectional view of a gold bump forming step which is a manufacturing step of the electronic component of FIG. 1;

FIG. 3 is a sectional view of a solder bump forming step after the gold bump forming step of FIG. 2;

FIG. 4 is a sectional view of a flux transfer step after the solder bump forming step of FIG. 3;

FIG. 5 is a cross-sectional view showing a conventional method for forming solder on an electrode on a substrate on which electronic components are mounted.

FIG. 6 is a sectional view showing a method for mounting a conventional electronic component on the substrate of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Electrode on substrate 3 IC chip 4 Aluminum electrode 5 Gold bump 6 Solder bump 7 Flux

Claims (3)

(57) [Claims] (1) The IC chip is adsorbed on the heating table
Forming a gold bump on a predetermined portion of the chip;
Supply solder while supplying antioxidant gas onto the pump.
Forming a solder bump, and applying the acid to the solder bump;
Illuminate the solder bumps while continuing to supply
To increase the bonding strength by heating and melting.
A method for manufacturing an electronic component, comprising: (2) The IC chip is adsorbed on the heating table
Forming a gold bump on a predetermined portion of the chip;
Supply solder while supplying antioxidant gas onto the pump.
Forming a solder bump, and applying the acid to the solder bump;
Illuminate the solder bumps while continuing to supply
And increasing the bonding strength by heating and melting,
The solder bump is immersed on a thin film of flux,
The step of transferring flux to the bump surface and the flux
Solder bumps with solder transferred on the substrate on which electrodes are formed
And bonding to the electronic component.
Implementation method. (3) An adsorption device for adsorbing an IC chip;
A gas supply for supplying an antioxidant gas to a predetermined portion of an IC chip.
Feeding device and a wire bonder at a predetermined portion of the IC chip.
A device that supplies solder in a soldering method and forms solder bumps;
The solder bumps are irradiated with light to raise the temperature and melt to increase the bonding strength.
At least a light irradiation device for increasing
An electronic component manufacturing apparatus, characterized in that: