JP2002050656A - Apparatus and method of mounting electronic component element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method of mounting electronic component elements, which suppresses deposition of the oxides of silicon, iron, etc., on the top end of a tool and thereby stably bonding by the ultrasonic welding for a long time. SOLUTION: The mounting apparatus has a tool for vacuum chucking electronic component elements 1 and feeding each element 1 with ultrasonic thermocompression bonding. A hard oxidation-resistive member 60 is disposed on the top end face of the tool 41 for vacuuming the electronic component elements 1 and the atmosphere during bonding uses an inert gas atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component mounting apparatus for bonding an electronic component formed with a protruding electrode to a wiring board by ultrasonic thermocompression bonding and a mounting method thereof.

[0002]

2. Description of the Related Art A flip-chip mounting method (electronic component element mounting method) has been widely used as a method for mounting electronic component elements such as IC chips having projecting electrodes on a wiring board at high density. I have. As a common example,
There is a flip chip mounting method. This is a method in which a protruding electrode and a pad electrode are brought into contact with each other, and are joined by applying a load and ultrasonic vibration while heating.

[0005] The protruding electrodes are generally formed by a ball bonding method using a metal wire. For example, a protruding electrode formed by a ball bonding method using a metal wire joins a ball formed by melting a portion protruding from the tip of a capillary with a torch or the like to an input / output pad formed on a mounting surface of an electronic component element.
Next, it was formed by extending the wire upward.

Thus, the protruding electrode is regulated from the input / output pad side of the electronic component element by the bump pedestal formed by melting and pressing the tip of the wire and the tip of the wire capillary on the pedestal. And a spire formed by drawing a wire on the chamfer. Note that Au, Cu, Ag, or the like can be used as a material for the protruding electrode.

Further, the mounting apparatus has a tool (horn) that sucks and holds the upper surface (the surface opposite to the mounting surface) of the electronic component element and can supply ultrasonic thermocompression bonding to the electronic component element. It is composed of a work fixing table that holds the wiring board, and both the tool side and the work fixing table side can perform positioning in XY direction control (plane control) and Z axis direction control (height control). .

[0006] Japanese Patent Application Laid-Open No. 11-74315 and
Tool (horn) as exemplified in 1-135574
For the portion, a flat collet shape or a pyramid different collet shape made of tungsten carbide or SUS was used.

[0007]

However, in the conventional flip-chip mounting tool and flip-chip mounting apparatus, when the bonding between the electronic component element and the wiring board is performed, the electronic component depends on the degree of progress of the bonding. The bonding strength between the element and the wiring board gradually increases. as a result,
In the initial state of the joining, the ultrasonic thermocompression bonding concentrated on the joining portion between the electronic component element and the wiring board is concentrated on the adsorption portion between the tool and the electronic component element at the end of joining. That is, frictional heat or ultrasonic thermocompression slip occurs in this portion, and the reaction is promoted in the tool and the electronic component element. As a result, an oxide of the material of the tool itself is generated on the tip surface of the tool. For example, when SUS303 is used as the material of the tool, an oxide of the iron component of SUS adheres.

[0008] The iron oxide deposited and deposited on the tool causes cracks on a part of the surface of the electronic component element in the next adsorption of the electronic component element, and also causes the adsorption between the tool and the electronic component element. There is a problem of causing a decrease in the image quality.

Further, when the electronic component element is formed of, for example, silicon such as an IC chip, deposits of silicon oxide are deposited on the tip surface of the tool. This is presumably because silicon is activated between the tool and the surface of the IC chip under the influence of ultrasonic vibration and the like due to the influence of ultrasonic vibration and the like.

The present invention has been devised in view of the above-mentioned problems, and has as its object to effectively suppress the adhesion of oxides such as iron and silicon to the tip of a tool, and to provide an ultra An object of the present invention is to provide an electronic component device mounting apparatus and a mounting method capable of stably performing sonic fusion.

[0011]

The flip-chip mounting apparatus of the present invention has a tool for holding an electronic component element by suction and supplying ultrasonic thermocompression bonding to the electronic component element. An electronic component element mounting apparatus for joining an electronic component element having a protruding electrode formed on a surface thereof to a wiring board having a predetermined pad electrode formed thereon by ultrasonic thermocompression bonding. The electronic component element mounting apparatus is characterized in that a hard oxidation-resistant member is disposed on a tip end surface for adsorbing the electronic component element.

The hard oxidation-resistant member is made of any one of sapphire, artificial diamond, alumina titanium carbide, zirconia, and diamond-like carbon.

Further, the hard oxidation-resistant member is formed on the tip end surface of the tool for adsorbing the electronic component element by one of a thin film technique of a thermal spraying method, a magnetron sputtering method, and a plasma CVD method.

Further, the hard oxidation-resistant member is formed by bonding a thin plate obtained by slicing any one material of sapphire, artificial diamond, alumina titanium carbide, and zirconia to a tip end surface of a tool for adsorbing electronic component elements. I have.

An electronic component having a protruding electrode formed on a mounting surface by using an electronic component device mounting apparatus having a tool for sucking and holding the electronic component element and supplying ultrasonic thermocompression bonding to the electronic component element. An electronic component mounting method for bonding an element to a wiring board on which a predetermined pad electrode is formed by ultrasonic thermocompression bonding, wherein the bonding by ultrasonic thermocompression is performed in an inert gas atmosphere. This is a method for mounting the element.

An inert gas atmosphere at the time of the ultrasonic thermocompression bonding is formed by injecting an inert gas into at least a suction portion between the electronic component element and the tool.

Further, as the inert gas, at least one of helium gas, argon gas and nitrogen gas is used.

According to the present invention, adhesion of metal oxides such as silicon and iron on the tip surface of the tool caused by the ultrasonic fusion process or long-term use is effectively suppressed.

A first aspect of the present invention is a mounting device for an electronic component element, wherein a hard and oxidation-resistant member is disposed on a tip end surface of a tool, that is, a surface for adsorbing the electronic component element. . For example, the hard oxidation-resistant member is any one material of sapphire, artificial diamond, alumina titanium carbide, zirconia, and tire monde carburone. Thereby, for example, even if ultrasonic fusion is performed using a tool formed of SUS or the like containing iron or the like,
The tip surface of the tool, that is, the surface that adsorbs electronic component elements,
It is always chemically stable and does not adhere to oxides such as iron. In addition, the adhesion of silicon oxide can be effectively suppressed.

As a result, it is possible to stably perform flip chip mounting by ultrasonic fusion bonding after exchanging tools for a long period of time.

Further, because of the rigidity, the ultrasonic vibration from the tool can be effectively transmitted to the electronic component element.

Further, since it is an oxidation-resistant member, it is chemically stable even if the temperature rises at the adsorption interface between the tool and the electronic component element in the final step of ultrasonic fusion, and it is chemically stable. Generation can be suppressed.

As the hard oxidation-resistant member, a material such as sapphire, artificial diamond, alumina titanium carbide, or zirconia can be sliced and thinly adhered to the tip surface of the tool. In addition to the sliced thin plate, thermal spraying, magnetron sputtering, plasma C
By the VD method or a combination of these methods, the tip surface of the tool can be coated to form the hard oxidation-resistant member.

In the flip chip mounting method, the above-mentioned means uses a hard oxidation-resistant member.
As another means, the joining operation is performed in an inert gas atmosphere using an inert gas. As a result, the concentration of oxygen necessary to generate an oxidized part is reduced, and the generation of oxide is suppressed.

The inert gas is at least one gas selected from the group consisting of helium gas, argon gas, and nitrogen gas. Even if such a gas is blown near the tip of the tool by using a nozzle, the inert gas is sprayed. I do not care.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electronic component device mounting apparatus and a mounting method thereof according to the present invention will be described.

FIG. 1 is a side view showing a state in which an electronic component element according to the electronic component element mounting apparatus and the mounting method of the present invention is flip-chip mounted on a wiring board, and FIG. It is a side view of the state which carried out. FIG. 3 is a schematic view of a mounting apparatus of the present invention, and FIG.
It is an enlarged view of the tip part of a tool. Hereinafter, the electronic component mounting apparatus will be described as a flip-chip mounting apparatus based on the mounting method.

In the figure, 1 is an electronic component element, 2 is a wiring board, and 3 is a protruding electrode. The electronic component element 1
For example, an IC chip or a SAW element is used. On the mounting surface, input / output pads 11 for power supply, ground connection, signal input / output, and the like of IC chips and SAW elements are formed. And as shown in FIG.
The projecting electrode 3 is formed on the input / output pad 11. The protruding electrode 3 is regulated by a bump pedestal portion 3a in which a sphere is crushed vertically from the input / output pad 11 side and a tip end of the capillary, and a substantially circular chamfer portion 3b and a wire extending ( And a spire portion 3c formed by tearing.

As the wiring board 2, a flat circuit board or a ceramic package having a cavity is used. The surface of the circuit board or the bottom of the cavity is provided on the circuit board.
Pad electrode 21 to be joined to bump electrode 3 of electronic component element 1
Are formed.

The above-mentioned protruding electrode 3 is formed by, for example, a ball bonding method using an Au wire. Specifically, a predetermined amount of wire is extended from the tip of the wire capillary, and the protruding portion is heated with a torch or the like, and the tip is melted to form a ball. In this state, the ball is pressed against the input / output pad of the electronic component element 1 to join the wire to the input / output pad 2 of the electronic component element 1. Thereafter, the wire itself is extended upward and torn. Thus, as described above, the protruding electrode 3 includes the bump pedestal portion 3a, the chamfer portion 3b regulated by the tip shape of the capillary (inside champa portion of the capillary), and the spire portion 3c formed by extension. become. In addition, when extending | stretching is simply extended upward, it becomes the spire part which extends upward like FIG. When a spire portion is formed and further extended downward in a hairpin shape following the upward extension, a spire portion having a U-shaped tip is obtained. Furthermore, in order to stabilize the length of the spire section, Au containing a small amount of Pd or the like is added.
It is desirable to use a wire.

On the other hand, the pad electrode of the wiring board 2 has a base conductor film such as tungsten (W) or molybdenum (Mo) formed on the surface of a ceramic material of the substrate, and the surface thereof is plated with Ni or Au. Have been.

In mounting such an electronic component element 1 on the wiring board 2, both are mounted using a flip-chip mounting apparatus (specifically, a bonding apparatus).

The mounting apparatus includes a tool 41 for vacuum-sucking the upper surface of the electronic component element 1 opposite to the mounting surface, an ultrasonic thermocompression contactor 42 for supporting the tool 41 and generating a predetermined ultrasonic thermocompression, and a transducer 43. Moving the electronic component element 1 sucked by the tool 41 to a predetermined position,
A control system for controlling the amount of load applied to the electronic component element 1 is provided. For example, an XY-axis driving unit 44 that controls the horizontal direction of the drawing and a depth direction of the drawing, a z-axis driving unit 45 that controls the operation in the vertical direction of the drawing, and a θ rotation driving unit 46 that operates around the rotation axis. And

The tool 41 has a suction hole 47 formed therein, which is connected to a vacuum source. Also, the tool 41
Has a heating means (not shown) so that the electronic component element 1 sucked and held by the tool can be heated to a predetermined temperature.

The device for fixing the work includes a fixing table 51 for fixing the work, a heating table 52 for heating the fixing table 51, and a driving unit 53 for positioning the fixing table in the X and Y directions. I have. The fixing table 51 and the heating table 52 communicate with each other via a suction hole 55, and are connected to a vacuum source.

As described above, the wiring board 2 on which the pad electrodes 21 are formed is held in the cavity of the work fixing table 51 and is fixed via the suction holes 55. Further, the wiring board 2 is heated to a predetermined temperature by the heating table 52, so that bonding reliability by ultrasonic thermocompression bonding is improved.

At the tip of the tool 41, a surface opposite to the mounting surface of the electronic component element 1 is held by suction, and the XY driving unit 44 and the Z-axis driving unit 4 are operated by image recognition or the like.
5. Further, the electronic component element 1 is
Will be positioned at a predetermined position so that is mounted at a predetermined position on the wiring board 2.

Using such a mounting device, first, after the positioning of the wiring board 2 in the work fixing table 51 and the electronic component element 1 held by the tool 41 is completed, for example,
The wiring board 2 is heated by the heating table 52 or the heating means on the tool 41 side.
Then, the electronic component element 1 is subjected to a heat treatment. In addition, in the case of the electronic component element 1 whose characteristics fluctuate by direct application of heat, it is desirable that heating be performed only on the fixed base 51 side. For example, the temperature heated by heating is, for example, 200 ° C.
It is.

Next, by controlling the vertical direction of the paper surface, for example, the Z-axis drive unit 12, the mounting surface of the electronic component element 1 held by the tool 41 is fixed to the predetermined position of the wiring board 2 held by the work fixing table 51. Lower to position. Due to this drop, the spire portion 3c of the protruding electrode 3 of the electronic component element 1
Contact with the predetermined pad electrode 21. The actual joining process is performed in a state where the two are in contact with each other.

In the present invention, as shown in FIG.
The tip surface for adsorbing the electronic component element is made of a hard material having excellent oxidation resistance, that is, a hard material made of any one of sapphire, artificial diamond, alumina titanium carbide, zirconia, and tire monde carbon. An oxidation-resistant member layer 60 is provided.

In FIG. 4, the hard oxidation-resistant member layer (hereinafter, referred to as an adsorption layer) 60 is made of the above-described material, for example, 0.5 to 0.5%.
It was sliced to a thickness of 2.0 mm, and was adhered and fixed to the tip of the tool 41 via a heat-resistant adhesive.

The suction layer 60 has a suction tip hole 61 penetrating the thickness direction thereof and communicating with the suction hole 47 of the tool 41. As shown in FIG. 4, the holes 61 are formed at the same positions and with the same diameter as extensions of the suction holes 47.

As shown in FIG. 4, a concave portion 62 is formed at the center of the tip of the tool 41. This is because a material such as amina titanium carbide or zirconia, which can be easily processed into a round shape, has a part thereof fitted into the concave portion 562 and fixed by adhesion, and is a material which is difficult to process the adsorption layer 60. In some cases, the recess 62 may be treated.

As described above, since the tip of the tool 41 is formed with a suction layer made of a hard material, ultrasonic thermocompression is supplied from the tool 41 to the electronic component element 1 in order to perform ultrasonic fusion. Also, the vibration is not absorbed by the adsorption layer 60, and the predetermined vibration can be stably propagated.

The adsorption layer 60 also has oxidation resistance and is chemically stable, so that the bonding between the electronic component element 1 and the wiring board 2 proceeds, and the ultrasonic vibration is applied to the tool 41 (adsorption layer 60). Even if it concentrates on the adsorption interface between
Unlike the conventional case, the metal material forming the tool 41 is never oxidized to generate oxide. In addition, the adsorption part of the electronic component element 1 is deteriorated. For example, when the electronic component element 1 is an IC chip having a silicon base, the metal material of the tool 41 diffuses as an impurity in the chip, or silicon oxide Alteration such as advancing the layer is effectively suppressed.

Here, it is important that the thickness of the suction layer 60 is made thin enough to form the suction tip hole 61 and slice it.

In the above-described embodiment, the adsorption layer 60 is formed on the tip of the tool 41 so that the tip surface of the tool 41 is hard and has excellent oxidation resistance, ie, sapphire, artificial diamond, alumina titanium carbide, zirconia. A member obtained by slicing any one of the above materials is adhered to the adsorption layer 60.
Has been arranged. For diamond-like carbon, a substrate having this material adhered to the surface is used.

As another embodiment, as a method of forming the adsorption layer 60, sapphire, artificial diamond, alumina titanium carbide, zirconia, and diamond-like carbon are used in addition to slices, by thermal spraying, magnetron sputtering, plasma CVD (chemical vapor deposition). ) And a thin film technique using these methods in combination, a coating may be formed on the tip end surface of the tool 41.

In this case, since the suction layer 60 can be formed according to the tip shape of the tool 41, it is particularly suitable for the tool 41 having a complicated structure.

Further, in the suction layer 60 formed by bonding the sliced members, it is necessary to perform management so that the slice surface, which is the suction surface, does not have irregularities that may cause a problem in suction. In the case of forming by more, it is not necessary to manage the surface flatness and the like.

The thickness of the adsorbing layer 60 is about 1 μm to 2.0 mm in consideration of the case where the adsorbing layer 60 is formed by bonding the slice member and the case where it is formed by thermal spraying.

The present inventor has proposed a flip chip mounting apparatus having a tool 41 on which such an adsorption layer 60 is arranged,
Ultrasonic welding of the IC chip chip and the wiring board 2 as the electronic component element 1 was performed, and the attached matter on the tip of the tool 41 was examined. As a result, since the tool 41 and the IC chip were separated by the adsorption layer 60 in the adsorption to the IC chip, generation of an oxide by iron was not recognized.

Further, the amount of the silicon oxide deposit was measured by EPMA (Electronic Wavelength Dispersion Type Alarizer), and the generation was quantitatively evaluated.

As the tip of the tool, sample 1
The material of the tool 41 is SUS303 and the tip portion is not processed, and the sample 2 is that the material of the tool 41 is SUS3.
Sample No. 03 was coated with MOST (molybdenum disulfide) on the tip, and sample 3 was made of SUS440
Quenched and coated with molybdenum disulfide, sample 4 was a tool 41 made of SUS303 and diamond-like carbon at the tip was spray-coated, and sample 5 was a tool 41 made of SKD steel. The sample 41 was coated with diamond-like carbon and spray-coated with a thickness of 3 μm.
03, a 1.5 mm thick thin plate of sapphire material adhered to the tip, sample 7 is a tool 41 made of SUS303 and a 1.5 mm thick artificial diamond slice member adhered to the tip, sample 8 is a tool 41 made of SUS303 having a thickness of 1.5 at the tip.
For the sample 9, the tool 41 was made of SUS303 and a 1.5 mm-thick zirconia slice member was adhered to the tip of the sample 41.

[0054]

[Table 1]

As a result, with respect to a tool in which the tip of the tool 41 is not processed as in the prior art, the frequency of occurrence of deposits was 2 digits, but the samples 4 to 9 of the present invention were not used.
It was confirmed that the frequency of occurrence of deposits was significantly reduced to 3 to 9 with the tool of (1).

Incidentally, such sapphire including the sample,
Artificial diamond, alumina titanium carbide, zirconia,
It has been confirmed that even if any one of diamond-like carbon is coated by a thin film technique such as thermal spraying or a sliced thin plate is bonded, the effect of suppressing the generation of deposits on the suction surface of the tool 41 is large.

In the above-described embodiment, the tip portion of the tool 41 is subjected to a tip treatment by a hard and oxidation-resistant member.

In order to obtain the same effect without performing such a tip treatment, the ultrasonic thermocompression bonding may be performed in an inert gas atmosphere. Specifically, at least one of helium gas, argon gas, and nitrogen gas is used as the inert gas. The inert gas atmosphere of the ultrasonic thermocompression bonding at least includes the electronic component 1 and the tool 4.
Inert gas is injected and supplied to the adsorbed portion 1.

For example, as shown in FIG. 5, a nozzle 65 capable of injecting the above-mentioned inert gas is provided around the electronic component element 1 and the work fixing 51 adsorbed on the tool 41, and the nozzle is inert during the entire mounting process. Perform in a gas atmosphere. In addition, when the adhesion of the oxide is taken into consideration, an inert gas may be injected around the adsorbed portion between the electronic component element 1 and the tool 41 at least during the supply of the ultrasonic thermocompression bonding. Incidentally, 66
Is a control plate for allowing the inert gas to concentrate on the bonding.

As a result, oxygen necessary for forming oxides is cut off. As a result, oxides such as iron and silicon are not generated in the tool 41.

As described above, an oxide such as iron or silicon adhered to the tool 41 is treated at the tip of the tool 41,
In other words, both the formation of the hard oxidation-resistant member and the control of the atmosphere (introduction of the inert gas) can be more effectively suppressed.

[0062]

According to the electronic component device mounting apparatus and the mounting method according to the present invention, it is possible to effectively prevent the oxide from adhering to the tip surface of the tool where the electronic component device is sucked. As a result, at the time of mounting the electronic component element, chipping or cracking of the electronic component element due to the adhesion of the oxide is unlikely to occur, and the interval of work for removing the oxide attached to the tool is greatly lengthened. And productivity can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a side view showing a state in which an electronic component element according to the present invention is flip-chip mounted on a wiring board.

FIG. 2 is a side view illustrating a protruding electrode of the electronic component element according to the present invention.

FIG. 3 is a schematic view of a flip chip mounting apparatus of the present invention.

FIG. 4 is an enlarged view of a tip portion of a tool of the flip chip mounting apparatus according to the present invention, (a) is a bottom view, (b)
Is a sectional view.

FIG. 5 is an enlarged view of a tip portion of a mounting device and a tool used in the flip chip mounting method of the present invention.

[Explanation of symbols]

 1 ・ ・ Electronic component element 2 ・ ・ Wiring board 3 ・ ・ Protruding electrode 41 ・ ・ Tool 60 ・ ・ Hard oxidation resistant member 65 ・ ・ Injection nozzle

Claims (7)

[Claims] An electronic component element is held by suction.
A tool for supplying ultrasonic thermocompression bonding to the electronic component element is provided, and the electronic component element having the protruding electrode formed on the mounting surface is bonded to the wiring board on which the predetermined pad electrode is formed by ultrasonic thermocompression bonding. An electronic component mounting apparatus, wherein a hard oxidation-resistant member is provided on a tip end surface of the tool for adsorbing electronic component elements. 2. The electronic component mounting apparatus according to claim 1, wherein said hard oxidation-resistant member is made of any one of sapphire, artificial diamond, alumina titanium carbide, zirconia, and diamond-like carbon. . 3. The hard oxidation-resistant member is formed on a tip surface of a tool for adsorbing an electronic component element by one of a thin film technique of a thermal spraying method, a magnetron sputtering method, and a plasma CVD method. 2. The electronic component element mounting apparatus according to claim 1, wherein: 4. The hard oxidation-resistant member is formed by bonding a thin plate obtained by slicing any one material of sapphire, artificial diamond, alumina titanium carbide, and zirconia to a tip end surface of a tool for adsorbing an electronic component element. 2. The electronic component element mounting device according to claim 1, wherein 5. An electronic component having a protruding electrode formed on a mounting surface using an electronic component device mounting apparatus having a tool for holding an electronic component element by suction and supplying ultrasonic thermocompression bonding to the electronic component element. An electronic component mounting method for bonding an element to a wiring board on which a predetermined pad electrode is formed by ultrasonic thermocompression bonding, wherein the bonding by ultrasonic thermocompression is performed in an inert gas atmosphere. Element mounting method. 6. The electronic component element according to claim 5, wherein an inert gas atmosphere at the time of the ultrasonic thermocompression bonding is formed by injecting an inert gas into at least a suction portion between the electronic component element and the tool. How to implement. 7. The method according to claim 5, wherein the inert gas is at least one of helium gas, argon gas and nitrogen gas.