JP3454154B2 - Thermocompression device and thermocompression method for work - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work thermocompression bonding apparatus and a thermocompression bonding method for thermocompression bonding works to each other.

[0002]

2. Description of the Related Art Thermocompression bonding is known as a method for bonding works such as electronic parts and substrates. In this method, the electronic component and the substrate are heated while pressing the electronic component against the substrate with a predetermined load to thermocompression-bond the joint portion. In the process of thermocompression bonding, various means are used in order to prevent deterioration of bondability due to oxidation of the surface. A method using an inert gas is known as one of the means. In this method, a low oxygen atmosphere is formed by supplying an inert gas such as nitrogen gas around the joint to fill the periphery of the joint with an inert gas, and the joint such as an electrode is exposed to oxygen in the air To avoid contact with.

[0003]

However, in the conventional thermocompression bonding apparatus for a workpiece, the periphery of the thermocompression bonding tool is simply surrounded by a cover member, and a nitrogen gas is introduced into the inside by a pipe or the like to release the nitrogen gas. Therefore, the released nitrogen gas flows out to the outside without staying inside the cover member,
There is a problem in that it is difficult to stably and evenly fill the periphery of the joint with nitrogen gas, so that a low oxygen atmosphere is not stably formed, and as a result, the joint quality is not stable.

Therefore, the present invention has an object to provide a thermocompression bonding apparatus and a thermocompression bonding method for a work which can form a stable and uniform low oxygen atmosphere around the bonding portion and stabilize the bonding quality. And

[0005]

According to a first aspect of the present invention, there is provided a thermocompression bonding apparatus for a work, an elevating block which moves forward and backward with respect to a first work, and a porous member which is attached to a lower surface of the elevating block and has air permeability. A heat generating means attached to the surface of the porous member on the opposite side of the elevating block, a thermocompression bonding tool attached in contact with the heat generating means and abutting and pressing the second work, and a porous member And a cover member that guides the inert gas flowing out from the side surface of the porous member toward the first work and the second work , the gas supply means including: Supply
The source, the nitrogen gas source and the types of these gases.
And a gas switching means for changing the gas .

According to a second aspect of the present invention, there is provided a thermocompression bonding apparatus for a work, comprising a stage on which a holding portion for the first work is mounted, a porous member having air permeability attached to the stage, and the first work. A holding member for holding, a gas supply means for supplying an inert gas to the porous member, and a cover member for guiding the inert gas flowing out from the side surface of the porous member to the first work and the second work side. Equipped with.

A thermocompression bonding device for a work according to a third aspect is the thermocompression bonding device according to the second aspect, wherein the gas supply means is an air supply source, a nitrogen gas supply source, and these. And a gas switching means for switching the type of gas.

[0008] Thermal bonding method as claimed in claim 4, wherein the workpiece is 請
Use the work thermocompression bonding device according to any one of claims 1 to 3.
A thermocompression bonding method, comprising:
While heating the second work, the first part of the second work is joined.
By pressing against the surface to be joined of the workpiece, the second
Is a thermocompression bonding method for thermocompression bonding the joint of the workpiece to the first workpiece, the joint of the second workpiece and / or the first joint being
Supplying an inert gas workpiece in proximity to the junction to disposed porous member of, the periphery of the junction and the junction by the inert gas flowing out of the porous member is a low oxygen atmosphere, Soldering was performed in this low oxygen atmosphere.

According to the invention described in each claim, the inert gas is diffused through the porous member into the cover member provided around the workpiece to be thermocompression bonded, thereby stabilizing the solder around the solder joint. As a result, a uniform low oxygen atmosphere can be formed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. 1 is a front view of a thermocompression bonding apparatus for a work according to an embodiment of the present invention, FIGS. 2A and 2B are cross-sectional views of a thermocompression bonding head of the thermocompression bonding apparatus for the same work, FIG.
4B and 4C are plan views of a thermocompression bonding head of the thermocompression bonding apparatus for the same work, and FIG. 4 is a sectional view of a thermocompression bonding stage of the thermocompression bonding apparatus for the same work.

First, the structure of a thermocompression bonding apparatus for a work will be described with reference to FIG. In FIG. 1, a stage 2 is provided on a movable table 1. A holding unit 3 for holding a substrate 4, which is a first work, is placed on the stage 2. A cover member 5 is arranged around the holding portion 3. By driving the movable table 1, the substrate 4 held by the holder 3 moves horizontally.

A Z-axis table 6 is disposed above the movable table 1, and an elevating block 7 is connected to the Z-axis table 6. A thermocompression bonding head 8 is attached to the lower end of the lifting block 7. The electronic component 10, which is the second work, is vacuum-sucked on the lower surface of the thermocompression bonding head 8, and the periphery of the thermocompression bonding head 8 is surrounded by a cover member 9. By driving the Z-axis table 6, the elevating block 7 moves up and down with respect to the substrate 4, and the electronic component 10 vacuum-sucked by the thermocompression bonding head 8 descends with respect to the substrate 4 on the holding unit 3. By heating the electronic component 10 and the substrate 4 while pressing the electronic component 10 against the substrate 4 with a predetermined load, the solder bumps 10a of the electronic component 10 are solder-bonded to the electrodes 4a of the substrate 4 by thermocompression bonding. It

Next, referring to FIGS. 2 and 3, the thermocompression bonding head 8 is provided.
The structure of is explained. FIG. 2A shows a vertical cross section that crosses the center of the thermocompression bonding head 8 in the width direction.
FIG. 2B shows a vertical cross section orthogonal to the cross section of FIG. In FIG. 2A, a porous member 12 and a ceramic heater 13 as a heat generating means are provided on the lower surface of the elevating block 7 via a spacer 11 made of a heat insulating material.
It is fixed by bolts 15 in a state of being overlapped (see bolts 15 and bolt holes 30 shown in FIG. 3A). The porous member 12 is made of a material, such as a ceramic sintered body, which has innumerable fine pores. The ceramic heater 13 generates heat almost in proportion to the supplied electric current, and repeats the temperature rise / decrease by the electric current supplied according to the heating pattern set by the control means (not shown).

In contact with the lower surface of the ceramic heater 13,
A thermocompression bonding tool 14, which is a holding member, is detachably attached. Porous members 12 and ceramic heaters 13 are provided with holes 12a and 13a at their central portions, respectively, and thermocompression bonding tool 14 is provided with suction holes 18.
A tube member 16 is inserted inside the hole 12a,
The pipe member 16 is a seal member 19a composed of two O-rings.
It is communicated with the suction hole 17 provided in the elevating block 7 via the and the hole portion 13a and the suction hole 18.

By driving the vacuum suction section 21 as suction means connected to the suction hole 17 to perform vacuum suction,
Through the suction hole 17, the pipe member 16, and the hole portion 13a, the suction hole 1
Vacuum suction is performed from 8 (see arrow a), and the electronic component 10 is vacuum-sucked and held on the lower surface of the thermocompression bonding tool 14. Therefore, the inner hole of the pipe member 16 is a ventilation hole which is formed to penetrate the porous member 12 and communicates with the adsorption hole 18.
At this time, the ventilation between the inner hole of the pipe member 16 and the porous member 12 is blocked by the pipe member 16. Therefore, the pipe member 16 serves as a ventilation blocking unit. 21
Reference numeral a is a valve for switching ON-0FF of the vacuum suction means. As the ventilation blocking means, other than the pipe member 16, a method of sealing the inner wall of the hole 12a with a heat-resistant resin material or the like may be used. In the present embodiment, the thermocompression bonding tool 14 is provided separately from the ceramic heater 13, but the ceramic heater 13 may also function as the thermocompression bonding tool 14, and may be manufactured as an integral body. In this case,
The lower surface of the ceramic heater 13, which is the heat generating means, corresponds to the holding portion.

In FIG. 2A, the lower end of the air supply hole 20 provided in the elevating block 7 is the lower surface of the elevating block 7.
The space S between the porous member 12 is opened. An air supply source 23 as a gas supply means and a nitrogen gas supply source 2 are provided in the air supply hole 20 via a switching valve 22 as a gas switching means.
4 is connected. When either air or nitrogen gas is supplied to the air supply hole 20 through the switching valve 22 (arrow b
(Refer to FIG. 3), these gases fill the space S and then enter the fine pores of the porous member 12. And the porous member 1
2 is transmitted in the lateral direction, is diffused into the gap surrounded by the cover member 9, and is discharged downward as shown by an arrow c. At this time, in the process of permeating through the porous member 12, these gases take heat from the porous member 12 and the ceramic heater 13 to cool the porous member 12 and the ceramic heater 13, and at the same time, absorb the heat to gas. The temperature of itself rises.

Further, since the ceramic heater 13 is cooled by the gas passing through the porous member 12, the temperature of the ceramic heater 13 is lowered responsively when the energization of the ceramic heater 13 is stopped or reduced. That is, the ceramic heater 13 is attached to the porous member 12 and the porous member 12 has a structure in which a gas is passed to cool the porous member 12, so that it is possible to realize the responsiveness improvement at the time of temperature reduction, which has been difficult in the past.

FIG. 3A is a sectional view taken along the line BB in FIG.
The cross section, that is, the lower surface of the porous member 12 is shown. Further, FIG. 2A shows a cross section taken along the line AA of FIG. The cross section D-D of FIG. 3A is shown in FIG. In FIG. 2B, the hole 12 of the porous member 12
A tube member 25 is inserted into the holes 12b provided on both sides of a. The tube member 25 communicates with the suction hole 26 via the seal member 19b, and the ceramic heater 1
3 communicates with the hole portion 13b provided in No. 3. Hole 13b
Has an opening in a groove 28 provided on the lower surface of the ceramic heater 13 as shown in FIG. Therefore,
When the vacuum suction unit 22 connected to the suction hole 26 is driven while the thermocompression bonding tool 14 is in contact with the lower surface of the ceramic heater 13, the thermocompression bonding tool 14 causes the ceramic heater 13 to move.
Is vacuum-adsorbed on the lower surface of the. Reference numeral 21b is a valve. When the valve 21b is closed, the thermocompression bonding tool 14 can be removed from the ceramic heater 13.

As shown in FIGS. 3 (a) and 3 (b), a pin 29 is erected downward on the porous member 12,
The lower end portion thereof penetrates the ceramic heater 13 and comes into contact with a diagonal portion of the thermocompression bonding tool 14. By aligning the diagonal ends of the thermocompression bonding tool 14 with the pins 29, the thermocompression bonding tool 14 is positioned with respect to the ceramic heater 13 (see FIGS. 3A and 3C).

Next, the structure of the thermocompression bonding stage will be described with reference to FIG. This thermocompression bonding stage is substantially the same as the above-described thermocompression bonding head 8 in terms of the structure of functional parts, although the shape and dimensions are different. That is, the thermocompression bonding head 8 holds and heats the electronic component 10, while the thermocompression bonding stage holds and heats the substrate 4 on which the electronic component 10 is mounted. In FIG. 4, a holding unit 3 for a substrate 4 is placed on a stage 2, and a porous member 32 and a ceramic heater 33, which is a heating means, are fixed to the upper surface of the stage 2 via a spacer 31 made of a heat insulating material. Has been done.

In contact with the upper surface of the ceramic heater 33,
A holding member 34 that holds the substrate 4 is attached. In the central portions of the ceramic heater 33 and the porous member 32,
Hole portions 33a and 32a are provided, respectively, and a holding member 34 is provided with a suction hole 38. A pipe member 36 is inserted inside the hole portion 32a, and the pipe member 36 communicates with a suction hole 37 provided in the stage 2 via a seal member 19c, and at the same time, the hole portion 33a and the suction hole 38.
Is in communication with.

By driving the vacuum suction section 21 as suction means connected to the suction hole 37 to perform vacuum suction,
Through the suction hole 37, the pipe member 36, and the hole portion 33a, the suction hole 3
8 is sucked in vacuum, the substrate 4 is vacuum-sucked, and the holding member 34
Hold on top of. Therefore, the internal hole of the pipe member 36 is a ventilation hole that is formed so as to penetrate the porous member 32 and communicate with the adsorption hole 38. At this time, the pipe member 3
Ventilation between the inner hole of No. 6 and the porous member 32 is performed by the pipe member 36.
The pipe member 36 serves as a ventilation blocking means. Reference numeral 21c is a valve that switches ON-0FF of vacuum suction.

The upper end of the air supply hole 40 provided in the stage 2 is opened in the space S ′ of the porous member 32 on the upper surface of the stage 2. An air supply source 23 and a nitrogen gas supply source 24, which are gas supply means, are connected to the air supply hole 40 via a switching valve 41. When either air or nitrogen gas is supplied to the air supply hole 40 via the switching valve 41, the porous member 32 is filled with these gases after filling the space S ′.
Enter into the fine pores of. Then, it permeates the inside of the porous member 32 in the lateral direction, is diffused in the gap surrounded by the cover member 5, and flows out upward as shown by the arrow d. At this time, in the process of permeating through the porous member 32, these gases take heat from the porous member 32 to cool the porous member 32, and the temperature of the gas rises by taking the heat.

The thermocompression bonding apparatus for this work is constructed as described above, and its operation will be described below. First, in FIG. 1, the electronic component 10 is picked up from the electronic component supply portion (not shown) by the thermocompression bonding head 8, and the substrate 4 is placed on the holding member 3. At this time, by driving the vacuum suction unit 21, the electronic component 10 is vacuum-sucked by the thermocompression bonding tool, and the substrate 4 is vacuum-sucked by the holding member 34. Next, the movable table 1 is driven to horizontally move the substrate 4, and the substrate 4 and the electronic component 10 are aligned with each other.

Next, the Z-axis table 6 is driven to lower the thermocompression bonding head 8 to bring the electronic component 10 into contact with the substrate 4,
The electronic component 10 is pressed against the substrate 4 with a predetermined load. Along with this pressing operation, the ceramic heaters 13 and 33 are energized to generate heat, and the thermocompression bonding tool 14 and the holding member 3 respectively.
The electronic component 10 and the substrate 4 are heated via 4. As a result, the joint between the electronic component 10 and the electrode 4a of the substrate 4 rises in temperature according to the heating pattern, and when the temperature reaches a predetermined temperature, the solder bump 10a is melted and solder bonding is performed by thermocompression bonding, and then the predetermined pattern. Accordingly, the thermocompression bonding of the electronic component 10 to the substrate 4 is completed.

In the process of repeating the above thermocompression bonding operation, the temperature of the porous members 12, 32 gradually rises due to the heat generated from the ceramic heaters 13, 33. Therefore, the changeover valves 22 and 41 are connected to the air supply source 23 so as to prevent the temperature rise of the porous members 12 and 32 and prevent the heat from being transferred to the elevating block 7 and the stage 2 and causing thermal deformation of these members. The air is supplied from the air supply holes 20 and 40 into the spaces S and S ′. Thereby, the air permeates the porous members 12 and 32, and the porous members 12 and 32 are cooled.

In addition, after the electronic component 10 contacts the substrate 4, in the process in which the temperature rises, the solder melts, and the solder joint of the joint portion is performed, the switching valves 22 and 41 are connected to the nitrogen gas supply source 2.
4, the nitrogen gas is diffused from the porous members 12, 32 through the air supply holes 20, 40. As a result, the nitrogen gas fills the inside of the cover members 9 and 5, a low oxygen atmosphere is formed around the solder joint between the electronic component 10 and the substrate 4, and good solder joining is performed. At this time, the porous member 12,
The nitrogen gas diffused from 32 is uniformly discharged from the entire periphery of the porous members 12 and 32 through the fine pores in the porous members 12 and 32 to the entire area inside the covers 9 and 5, and thus is partially A stable low oxygen atmosphere is formed without causing nonuniformity. As a result, the soldering portion is shielded from oxygen during soldering, and good soldering is performed.

Since the cover members 5 and 9 are provided only on the side surfaces, the lower surface of the thermocompression bonding head 8 and the upper surface of the stage 2 are open without a cover, and work for setup change work and maintenance work is performed. It has excellent properties. Further, since the nitrogen gas is heated and its temperature rises when passing through the porous members 12 and 32, the electronic component 10 and the substrate 4 are surrounded by the high temperature nitrogen gas, and the heating efficiency at the time of solder bonding is improved. be able to. Thus, the porous member 1
It is possible to reduce the consumption of expensive nitrogen gas by making it possible to switch the type of gas supplied to 2, 32 and supplying nitrogen gas only during solder joining and supplying air for other simple cooling. Therefore, the cost can be reduced.

In this embodiment, an example in which the thermocompression bonding apparatus is provided with both the thermocompression bonding head and the thermocompression bonding stage described above has been described, but the present invention is not limited to the thermocompression bonding apparatus having both. However, it may be provided with only one of them. Further, although an example of solder joining is described as the type of thermocompression bonding, a method of joining using an anisotropic conductive material or a method of joining metal electrodes may be used.

[0030]

According to the present invention, the inert gas is diffused through the porous member into the cover provided around the work to be thermocompression bonded, so that the thermocompression bonding portion is stably and uniformly distributed. Therefore, a low oxygen atmosphere can be formed, and thus good thermocompression bonding can be performed. Further, the type of gas supplied to the porous member can be switched, and the inert gas is supplied only during thermocompression bonding, so that the consumption of expensive inert gas can be reduced and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a front view of a thermocompression bonding device for a work according to an embodiment of the present invention.

FIG. 2A is a sectional view of a thermocompression bonding head of a work thermocompression bonding apparatus according to an embodiment of the present invention. FIG. 2B is a sectional view of a thermocompression bonding head of a workpiece thermocompression bonding apparatus according to an embodiment of the present invention.

3A is a plan view of a thermocompression bonding head of a work thermocompression bonding apparatus according to one embodiment of the present invention. FIG. 3B is a plan view of a thermocompression bonding head of a work thermocompression bonding apparatus according to one embodiment of the present invention. (C) A plan view of a thermocompression bonding head of a thermocompression bonding device for a work according to an embodiment of the present invention

FIG. 4 is a cross-sectional view of a thermocompression bonding stage of the thermocompression bonding device for a work according to the embodiment of the present invention.

[Explanation of symbols]

2 stages 3 holding part 4 substrates 5, 9 cover member 7 lift block 8 thermocompression head 12,32 Porous member 13,33 Ceramic heater 14 Thermocompression bonding tool 16, 36 Pipe member 21 Vacuum suction unit 22,41 switching valve 23 Air supply source 24 Nitrogen gas supply source

─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-9-312314 (JP, A) JP-A-4-254338 (JP, A) JP-A-63-55949 (JP, A) JP-A-9- 45734 (JP, A) JP 56-158436 (JP, A) JP 7-201924 (JP, A) JP 8-162501 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/60 H01L 21/603 H01L 21/52 H05K 3/32 H05K 13/04 B23K 3/04

Claims (4)

(57) [Claims] 1. An elevating block that moves forward and backward with respect to a first work, a breathable porous member attached to a lower surface of the elevating block, and a surface of the porous member opposite to the elevating block. The attached heat generating means, a thermocompression bonding tool which is attached in contact with the heat generating means and abuts and presses against the second work, gas supply means for supplying an inert gas to the porous member, and the porous member. A cover member that guides the inert gas flowing out from the side surface of the first work and the second work to the side of the first work, and the gas supply means is an air supply source.
And the nitrogen gas supply source and the type of these gases
Thermocompression bonding device of a work, characterized in that a gas switching means for obtaining. 2. A stage on which a holding portion for a first work is placed, a porous member having air permeability attached to the stage, a holding member for holding the first work, and the porous member. Of the work, comprising: a gas supply unit for supplying an inert gas to the first work and a cover member for guiding the inert gas flowing out from the side surface of the porous member to the first work and the second work. Thermocompression bonding device. 3. The work thermocompression bonding apparatus according to claim 2 , wherein said gas supply means includes an air supply source, a nitrogen gas supply source, and a gas switching means for switching types of these gases. . 4. A thermocompression bonding method using the thermocompression bonding device for a work according to claim 1, wherein the second work is joined while heating the first work and / or the second work. A thermocompression bonding method for pressing a joint portion of a second workpiece to the first workpiece by pressing the portion against the surface to be joined of the first workpiece, and the joint portion of the second workpiece and / or An inert gas is supplied to a porous member arranged in the vicinity of the joined portion of the first work, and the inert gas flowing out from the porous member lowers the circumference of the joined portion and the joined portion. A thermocompression bonding method for a work, which comprises forming an oxygen atmosphere and performing soldering in the low oxygen atmosphere.