JP4854105B2 - Thin film solar cell module and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device and a method for manufacturing the semiconductor device, and more particularly to a solar cell module, in particular, a device that performs photoelectric conversion using a thin film semiconductor layer including amorphous silicon, a so-called thin film solar cell module and a method for manufacturing the same. . More specifically, the present invention relates to the structure of the solar cell module in the positive / negative electrode take-out stage and the method of attaching a good electrical conductor.
[0002]
[Prior art]
Solar power generation has become popular as a means of solving environmental problems such as resource depletion or an increase in the amount of carbon dioxide generated, and thin-film solar cells are attracting attention because they use less semiconductor materials such as silicon Has been.
[0003]
Thin-film solar cells have a low efficiency of converting light into electric power compared to solar cells using crystal substrates that have been put into practical use, but the appearance of the light incident surface after installation is the same as that of crystal substrates. Compared with solar cells, 1) The color tone is brown or black and similar to the roof of a house or building. 2) Solar cells in the form of strips arranged closely without the wiring and internal mechanisms visible. Since the element exists on the entire surface, it has a feature such that it looks uniform from a distance, and has attracted much attention from the aspect of design.
In particular, a thin film solar cell module in which a solar cell element is directly formed on a transparent insulating substrate and connected on the substrate (hereinafter referred to as a substrate integrated solar cell module) has been proposed, and the area of the power generation region is the area occupied by the module It can be realized up to about 90%, and the parts other than the elements are hardly conspicuous.
[0004]
The structure of the solar cell portion of the substrate-integrated solar cell and the manufacturing method thereof are disclosed in US Pat. No. 4,292,092. A transparent conductive film is formed on a transparent insulating substrate such as glass and separated into strip-like individual photovoltaic regions by laser processing lines, and p-type, i-type and n-type amorphous silicon is formed on the entire surface. And a photovoltaic semiconductor layer. A connection groove for connecting to the next element is formed by laser processing at a position shifted parallel to the first processing line, and after forming the back electrode layer, it is parallel to the connection groove and opposite to the separation groove of the transparent electrode A back electrode separation groove is formed on the substrate. Through these steps, a thin film solar cell in which a plurality of strip-like photovoltaic elements are connected in series to one substrate is formed.
[0005]
With this configuration, the connected portion of the solar cell exists as a thin line having a width of 0.3 mm to 0.5 mm and cannot be recognized visually from a place 20 m away.
[0006]
In order to take out the electric power of the thin film solar cell, a bus means is provided at the terminal end of the connection or in the middle. Since the bus means is a part that does not contribute to power generation, a good conductor is installed in a strip-like area (bus area) slightly narrower than the photovoltaic element so that power can be collected more easily. As a good conductor, for example, as disclosed in JP-A-3-171675, a method in which a paste in which metal particles such as glass frit are dispersed is applied to a region immediately after forming a transparent electrode on a transparent insulating substrate, or As disclosed in 9-83001, there is a method in which the back electrode layer and the semiconductor layer in the bus region are linearly removed and a solder-plated copper foil is connected to the exposed portion of the transparent electrode with ceramic solder.
[0007]
Specifically, the former method is illustrated in FIG. 2, in which bus regions 3 and 3 ′ for collecting positive and negative power are provided on the thin-film solar cell 100, and a back electrode layer and a semiconductor layer are provided at the approximate center in the width direction. A portion 25 exposing the transparent electrode is formed by removing the bumps of the ceramic solder on which the lead, tin, zinc and antimony are essential components using an ultrasonic soldering iron. Are provided with solder-plated copper foils 4, 4 ′.
[0008]
[Problems to be solved by the invention]
The above-mentioned conventional technology is caused by the older technology of installing a good conductor with solder or conductive paste on the back electrode, such as corrosion due to the reaction between the paste material or solder material and the back electrode material, peeling of the connection part, etc. The invention was invented from the viewpoint of solving the problem by directly attaching a paste material or a solder material to the transparent electrode layer with very few problems of electrolytic corrosion between metals and peeling problems. In the method shown in (1), it was found that when the portion where the paste such as glass frit was in contact with the transparent electrode was viewed from the light incident side, it became a silver glossy portion.
[0009]
On the other hand, in the structure of Japanese Patent Laid-Open No. 9-83001, the metallic luster of the solder-plated copper foil is incident through the portion where the back electrode layer and the semiconductor layer are linearly removed and the transparent electrode is exposed at the approximate center in the width direction of the bus region. It turned out to be visible from the surface.
[0010]
These external features have been found to significantly impair the design of a solar cell module of the type installed as part of a building.
[0011]
That is, when a solar cell module is used as a building material such as a roof of a general house or a component in accordance with a building material, many architects are demanding designability similar to or exceeding that of conventional building materials. For example, when a solar cell is used as a roofing material, appearance characteristics such as a brown color tone, matteness, uniform surface and no pattern like a normal colonial tile or single are required.
[0012]
In this case, the metallic luster shown above is extremely distant from the color tone of the solar cell roofing material, which is not preferable because it becomes a conspicuous pattern.
[0013]
However, it is self-evident that the reliability of the method attached to the back electrode as in the previous technology is significantly reduced, and it is extremely important to propose a structure that satisfies both appearance and reliability. It is a problem.
[0014]
[Means for Solving the Problems]
The inventor has improved the solving means satisfying the above problems day and night starting from the structure disclosed in JP-A-9-83001, and as a result, the simple and clear means disclosed in the present invention as described in the claims. I found it.
[0015]
It is an aspect of the present invention, on one surface of the transparent insulating substrate, a transparent electrode layer, a photovoltaic thin-film semiconductor layer, laminated and a back electrode layer is made form, divided into a plurality of regions The photovoltaic thin film semiconductor layer having a photovoltaic element and a bus region formed is provided with a groove for connection to an adjacent unit photovoltaic element, and the unit photovoltaic element is connected in series by the groove. As a terminal of the connection, a bus region for extracting power at the positive and negative electrode extraction stages of the thin film solar cell module and a good conductor made of a metal wire or a metal ribbon for collecting power in the bus region are connected. A thin-film solar cell module having a transparent insulating substrate and a transparent electrode so that the connection between the bus region and the good conductor is discretely arranged in the longitudinal direction at the center of the width side of the bus region and the transparent electrode layer is exposed Leave the layer and And opening the removal of photovoltaic thin-film semiconductor layer or / and the back electrode layer, filling the openings is to perform bus region and conductor in mechanical and adhesive conductor electrically connecting.
[0016]
The adhesive conductor used here is a conductive liquid containing a conductive metal or organometallic component, such as a conductive paste, solidified by installing in the opening, or lead having adhesiveness to a ceramic material, Solder containing tin, zinc and antimony as essential components, more specifically 1 to 60% by weight of lead, 10 to 98% by weight of tin, 0.01 to 25% by weight of zinc and 0.01 to 50% by weight of antimony Are preferably used.
[0017]
The good conductor made of a metal wire or a metal ribbon is a copper wire or foil coated with solder or tin, preferably a solder-plated copper foil having a width of 2 mm or more, and the thickness of the solder plating is 50 μm or more, preferably 100 μm or more. , 200 μm or less is preferably used.
[0018]
As a manufacturing method of these structures, a photovoltaic thin film semiconductor layer is arranged so that the transparent electrode layer is exposed leaving the transparent insulating substrate and the transparent electrode layer discretely arranged in the longitudinal direction in the central portion on the width side of the bus region. Or / and providing a hole from which the back electrode layer is removed;
Installing an adhesive conductor bump in the opening;
This portion is implemented by connecting a good conductor made of a metal wire or a metal ribbon for collecting power in the bus region to the bump of the adhesive conductor.
The composition of the bump is dispensed with conductive liquid containing conductive metal or organometallic component such as conductive paste and cured with heat afterwards, or solder used for ceramic etc. or lead, tin, zinc and antimony as essential components The solder to be soldered may be attached with a soldering iron that oscillates ultrasonic waves and oscillates ultrasonic waves and is heated.
[0019]
To provide an opening, mechanically drill with a metal tool having a tip that is smaller than the size of the opening, or mechanically using ultrasonic waves with a metal tool such as an ultrasonic soldering iron. It can be carried out by a mechanical process of drilling into the substrate or by a thermal process using the radiant energy of the laser.
[0020]
Furthermore, although applicable only when using the above-mentioned solder, the step of providing the opening by optimizing the ultrasonic frequency and power of the ultrasonic soldering iron, the distance between the tip and the processing portion, By carrying out simultaneously with the step of installing the solder bumps in the openings, the step characteristic of the present invention can be realized in one step. As a device in this case, the ultrasonic soldering power is set so that the ultrasonic oscillation power is set to 10% or more larger than the conditions set for the device for the purpose of soldering the ceramic, and the power is always output. Cooling means is provided to lower the temperature of the oscillator in the iron part (only the speaker coil and ball piece are attached to the iron part).
[0021]
DETAILED DESCRIPTION OF THE INVENTION
A specific embodiment will be described below with reference to FIG. The content described here is to explain the form, and is not limited to this, and even if it takes another form, it can be applied as long as it reflects its technical idea.
[0022]
[Thin film solar cell]
The thin film solar cell used in the present invention is shown in the cross section of FIG.
[0023]
As the transparent insulating substrate 1 used in the thin film solar cell, glass or heat-resistant plastic is used. For example, SiO ₂ is formed on this substrate so that impurities of the substrate do not diffuse into the layers above it. A transparent electrode layer is formed thereon.
[0024]
As the transparent electrode layer 16, SnO ₂ grown in a form in which irregularities are formed by the apex angle of the crystal grains is preferably used. A thermal CVD method is generally used as the formation method.
[0025]
This transparent electrode layer is provided with a groove 18 by using a laser processing method or the like, and a strip-like individual region 17 is formed.
[0026]
A semiconductor layer 19 is formed thereon. As the semiconductor layer, a photovoltaic junction such as amorphous silicon, thin film polycrystalline silicon, CIS, or CdTe is appropriately formed. The material for the transparent electrode is appropriately selected from those suitable for these semiconductors.
[0027]
These semiconductor layers are provided with grooves 21 for connection to the adjacent photovoltaic elements.
[0028]
A back electrode layer 22 is formed on the semiconductor layer 19. As the back electrode layer, an electrode in which a transparent conductive material such as ZnO and a highly light reflective metal such as Ag are combined is preferably used.
[0029]
These back electrode layers 22 become individual electrodes 23 by grooves 24. With this configuration, the unit elements 28 in which the semiconductor is sandwiched between the transparent electrode and the back electrode are connected in series.
[0030]
Bus regions 3 and 3 ′ for collecting electric power are provided at both ends to which these elements 28 are connected. In this region, a plurality of discrete openings 29 for exposing the transparent electrode layer are provided.
[0031]
As a method for opening this hole, in the inventor's experiment, the semiconductor layer and the back electrode layer are efficiently formed by rubbing with a higher ultrasonic power than when soldering with an ultrasonic soldering iron chip described later. It was found that the transparent electrode layer can be exposed by removing. By utilizing this principle, it is possible to produce an industrially profitable device. In this case, since the oscillator is always in a state of oscillating, it has been found that the ultrasonic power is lowered because the heat is generated and the resonance point of the oscillator is changed as the heat is generated. As a countermeasure, it has been found that a stable ultrasonic power can always be secured by blowering or water cooling the oscillator. Further, with this improvement, even when the solder of the ultrasonic soldering iron is melted and attached to the tip of the soldering iron, it can be similarly cut and attached. In this case, the power and the distance between the iron tip and the bus area are reduced in the cutting process and the soldering process, and the iron tip is pressed with a large power in the cutting stage. It has been found that the two steps can be performed efficiently if the touch is made to float.
[0032]
On the other hand, as another method, it is possible in principle to discretely remove the back electrode and the semiconductor by setting the laser condition to a condition for partially removing the back electrode. However, it is necessary to wait for the appearance of an apparatus that implements this method at high speed.
[0033]
Bumps 26 made of ceramic solder are discretely formed in the openings. The diameters of these bumps or apertures are 2 mm in diameter, as disclosed in the applicant's published Japanese Patent Application No. 9-133503, and the distance between the centers of the bumps is about 20 mm.
[0034]
Ceramic solder contains rare earths so that it can be joined to transparent electrodes and ceramics, and is commercially available from Senju Metal Co., Ltd. under the trade name Cerasolza. These components are preferably those containing 1 to 60% by weight of lead, 10 to 98% by weight of tin, 0.01 to 25% by weight of zinc and 0.01 to 50% by weight of antimony. .
[0035]
As another embodiment, a bump is placed in the opening with a metal or conductive resin-based conductive paste using a dispenser or screen printing instead of ceramic solder. Thereafter, the bumps are formed by drying with hot air.
[0036]
As the conductive paste, a commercially available paste is preferably used. However, in carrying out the present invention, the color tone after drying needs to be a dark color. As the paste material, carbon-based, copper-based, and nickel-based materials are preferably used.
[0037]
The solder plated copper foil 4 is connected to the bumps 26. The solder-plated copper foil 4 is obtained by coating a copper foil having a thickness of about 0.2 mm and a width of several mm with ordinary eutectic solder. The corrosion resistance is improved by this coating, and there is an effect that solder connection can be easily made by simply placing the copper foil on the bump and pressing the copper foil with a soldering iron. Moreover, in order to ensure the strength of the bonding between the bumps and the solder, a soldering strength of at least 1 kg is necessary. In order to ensure this strength, the solder thickness on the solder-plated copper foil must be 50 μm or more. Preferably it is 0.1 mm.
[0038]
The reason why the solder strength decreases when the amount of solder is small is that the surface of the copper foil has irregularities of 0.1 mm or more with respect to the contact surface, and if there is not enough solder to fill the irregularities, the solder joint is not planar This is because it becomes point-like.
[0039]
Moreover, all the soldering processes used here are processes that do not use flux. This is because when the flux is used, the acid in the flux remains and the reliability is remarkably lowered.
[0040]
The subsequent steps are not described in detail in the specification of the present invention, but as described in FIGS. 3 and 4, first, as shown in FIG. A step of connecting another solder-plated copper foil 5 or 5 ′ to 4 or 4 ′.
[0041]
A step of setting the fillers 6 and 8 for embedding an insulating sheet as shown in FIG. 3B at a predetermined position with the insulating sheet 7 sandwiched between them.
[0042]
As shown in FIG. 3 (C), the solder-plated copper foils 5 and 5 'up to the power extracting and connecting means are bent at the terminal box installation position so that the end on the terminal box side is perpendicular to the substrate. A step of covering with a filler 9 covering the entire surface of the substrate having a slit 10 through which a solder-plated copper foil is passed.
[0043]
Specifically, as shown in FIG. 3 (D) and FIG. 4 (E), a small piece of Tedler sheet 13 having a notch that is slightly larger than the hole in the protective cover is set around the solder-plated copper foil on the filler sheet. Further, the process of setting the EVA sheet pieces 12 of substantially the same size and the process of covering the protective cover The solder-plated copper foil is taken out from the opening of the protective cover and temporarily fixed at a position where the copper foil and the protective cover do not contact with the heat-resistant tape. Step, see FIGS. 4F and 4G.
[0044]
And the solar cell module sealed through the process of heat-pressing with a double vacuum tank type laminator (abbreviation vacuum laminator) is produced.
[0045]
The steps shown in FIGS. 3 and 4 show the relationship with the elements formed in the steps after the structure of the present invention is formed. Of course, it is not limited to this configuration. Any element including the element of the present invention can be used as appropriate.
[0046]
【Example】
Next, an Example is shown by the amorphous-silicon solar cell comprised on the glass of the Example of this invention.
[0047]
Example 1
As the transparent insulating substrate 1, a blue plate glass having a short side of 50 cm, a long side of 100 cm, and a thickness of 4 mm was used. This glass is chamfered around the cut surface to prevent thermal cracking and mechanical destruction during the process.
[0048]
On this glass, 1000 ＳｉＯ of SiO2 was formed as an alkali barrier by thermal CVD, and 10,000 Å of fluorine-doped SnO ₂ was formed as the transparent conductive layer 16. The surface is uneven by the apex angle of the crystal grains.
[0049]
The transparent electrode layer 16 was provided with grooves 18 by a laser processing method using the second harmonic of a YAG laser.
[0050]
A p-type amorphous silicon carbide was formed as a 100 Å, i-type amorphous silicon as a 3000 Å, and n-type amorphous silicon as a 300 Å semiconductor layer 19 by plasma CVD.
[0051]
A groove 21 was provided for connection to the adjacent photovoltaic element using the second harmonic of the YAG laser.
[0052]
Further, 1000 mm of ZnO and 3000 mm of Ag were formed on the semiconductor layer 19 by sputtering to form the back electrode layer 22.
[0053]
These back electrode layers 22 formed grooves 24 using the second harmonic of a YAG laser to obtain individual electrodes 23. With this configuration, the unit elements 28 in which the semiconductor is sandwiched between the transparent electrode and the back electrode are connected in series. The width of this unit element is about 10 mm.
[0054]
Similarly, bus regions 3 and 3 ′ for collecting electric power at both ends of these elements using laser processing were provided with a width of 5 mm. The distance between the positive electrode bus region 3 ′ and the negative electrode bus region 3 was 48 cm.
The semiconductor and amorphous silicon were mechanically removed using an ultrasonic soldering iron every 2 cm in the width direction central portion of the bus region to form 48 openings 27 on one side and 96 on one side to provide bumps 26 for the cerasolzer. The size of this hole is 2 mm in diameter.
[0055]
A solder-plated copper foil 4 having a width of 2 mm, a copper foil thickness of 0.2 mm, and a solder thickness of 0.1 mm was connected to the bump.
[0056]
The peripheral region 27 of the substrate 1 was provided with a region where polishing was performed using a sand blasting method and no upper layer was present.
[0057]
The solder-plated copper foils 4 and 4 ′ on the bus region were adjusted so as to form a 0.1 mm gap so that the filler was filled in the gap between the copper foil and the element surface.
[0058]
Solder-plated copper foils 5 and 5 ′ having a length of 30 cm and a width of 5 mm were connected to a position 5 cm from the substrate end of the solder-plated copper foils 4 and 4 ′ on the bus regions 3 and 3 ′. The thickness of this copper foil and the thickness of the solder are the same as the above-mentioned solder plated copper foil.
[0059]
When the appearance of the solar cell module was observed from the light incident side, the color tone of the entire surface was wine red. The connection part of the solar cell was seen as a silver line of about 0.1 mm when viewed in the vicinity. When the bus area was observed, the bump portion appeared dark gray, but when observed at a distance of about 2 m, these points were not visible.
[0060]
It was found that the color of the solder was darker in color when the texture transparent electrode was used and when the planar transparent electrode was used.
[0061]
(Examples 2-3)
The connection portion of the present invention can be similarly formed by using a conductive paste instead of solder. When copper paste was used, the color tone seen from the light-irradiated surface became dark red, and the color tone was similar to that of amorphous silicon. Moreover, it turned out that it will become black when a chromium-type paste is used. It turned out that both were similarly inconspicuous when looking away from more than 2m.
[0062]
【The invention's effect】
As described above, according to the present invention, the method of connecting a good conductor to the bus region is performed by discrete bumps, and by providing those bases discretely, the appearance of the part can be greatly improved. Is possible.
[0063]
As a result, it has become possible to exhibit the appearance characteristics originally possessed by the substrate-integrated thin film solar cell, and to fully demonstrate the superiority of the thin film solar cell in building materials.
[Brief description of the drawings]
FIG. 1 is a perspective view of laminated members of a thin film solar cell module according to the present invention. FIG. 2 is a perspective view of laminated members of a thin film solar cell module according to a conventional example.
FIG. 4 is a wiring process diagram of the present invention (2).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Transparent insulating substrate 2 Power generation area | region 3, 3 'bus area | region 4, 4' means of increasing the conductance of a bus area | region (solder plating copper foil)
5,5 'Bus area and wiring to the connection means to output power to the outside (solder plated copper foil)
6 Filling material for embedding insulating sheet 7 Insulating sheet 8 Filling material for embedding wiring between insulating sheet and 5 9 Filling material 10 Opening provided in filling material for passing 5 wiring 11 Opening of back protection cover and 5 Filler 13 for embedding an insulating sheet of another insulating sheet 1211 with an opening for preventing contact with the wiring 13 Back surface protection cover 145 Opening 15 installed in the back surface protection cover for passing the wiring of 5 Insulating material 16 Transparent electrode layer 17 Individual transparent electrode 18 Groove 19 for individualizing the transparent electrode Semiconductor layer 20 Separately divided semiconductor layer 21 In order to connect adjacent photovoltaic elements to the semiconductor layer Provided groove 22 Back electrode layer 23 Individual back electrode 24 Groove 25 for separating back electrode Groove 26 for connecting conductance increasing means to bus region Solder bump 27 Thin film Insulating region 28 provided around solar cell Individual photovoltaic element 29 constituting thin-film solar cell Discrete aperture 100 for exposing transparent electrode layer Solar cell element

Claims (12)

On one surface of the transparent insulating substrate, a transparent electrode layer, a photovoltaic thin-film semiconductor layer, laminated and a back electrode layer is made form a photovoltaic element made is divided into a plurality of regions And a groove in the photovoltaic thin film semiconductor layer having a bus region for connection to the adjacent unit photovoltaic element, and the unit photovoltaic element is electrically connected in series by the groove, and the connection A thin-film solar cell module having a bus region for extracting power at the positive and negative electrode extraction stages of the thin-film solar cell module and a good conductor made of a metal wire or a metal ribbon for collecting power in the bus region,
Connection between the bus area and the good conductor
The photovoltaic thin film semiconductor layer and / or the back electrode layer is removed leaving the transparent insulating substrate and the transparent electrode layer so that the transparent electrode layer is exposed discretely in the center of the width side of the bus region. Open holes,
A thin-film solar cell module, which is formed by an adhesive conductor that fills the opening and mechanically and electrically connects a bus region and a good conductor.   The thin film solar cell module according to claim 1, wherein the adhesive conductor is obtained by installing a conductive liquid containing a conductive metal or an organic metal component in the opening and solidifying the conductive liquid.   2. The thin film solar cell module according to claim 1, wherein the adhesive conductor is ceramic solder or solder containing lead, tin, zinc and antimony as essential components.   2. The thin film solar cell module according to claim 1, wherein the good conductor is a copper wire or foil coated with solder or tin.   The solder containing lead, tin, zinc and antimony as essential components is 1 to 60% by weight of lead, 10 to 98% by weight of tin, 0.01 to 25% by weight of zinc and 0.01 to 50% by weight of antimony. The thin film solar cell module according to claim 3, wherein   2. The thin film solar cell module according to claim 1, wherein the good conductor is a solder-plated copper foil having a width of 2 mm or more, and the thickness of the solder plating is 50 μm or more, preferably 100 μm or more and 200 μm or less. Transparent on one surface of the insulating substrate, a transparent electrode layer, a groove provided in the form a photovoltaic thin-film semiconductor layer photovoltaic thin-film semiconductor layer, made form laminated further comprising a back electrode layer, a plurality A photovoltaic device and a bus region are formed by being divided into a plurality of regions, unit photovoltaic devices of the photovoltaic device are electrically connected in series by the groove, and a thin film solar cell module as an end of the connection Forming a thin-film solar cell having a bus region that collects electric power in the positive and negative electrode take-out stages,
The photovoltaic thin film semiconductor layer and / or the back electrode layer is removed so that the transparent electrode layer is exposed, leaving the transparent insulating substrate and the transparent electrode layer, discretely arranged in the longitudinal direction at the center of the width side of the bus region A step of providing a hole,
Installing an adhesive conductor bump in the opening;
And a step of connecting a good conductor made of a metal wire or a metal ribbon for collecting power in the bus region to the bump of the adhesive conductor.   The method of manufacturing a thin-film solar cell module according to claim 7, wherein the step of installing the bump of the adhesive conductor in the opening includes a step of dispensing a conductive liquid containing a conductive metal or an organic metal component.   The step of installing the bumps of the adhesive conductors in the openings includes a soldering iron that oscillates ultrasonic waves, and at least partially oscillates and heats the solder containing lead, tin, zinc and antimony as essential components. The method of manufacturing a thin film solar cell module according to claim 7, wherein the method is a step of attaching the thin film solar cell module.   8. The thin film solar according to claim 7, wherein the step of providing the aperture is a step of mechanically drilling using ultrasonic waves with a metal tool having a tip portion having a size equal to or smaller than the size of the aperture. Manufacturing method of battery module.   8. The method for manufacturing a thin-film solar cell module according to claim 7, wherein the step of providing the aperture is a step of thermally drilling using radiant energy of a laser.   The method of manufacturing a thin-film solar cell module according to claim 7, wherein the method is performed simultaneously with the step of providing the opening using a soldering iron that oscillates an ultrasonic wave and the step of installing a solder bump in the opening. .

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