WO2022118517A1

WO2022118517A1 - Production method for conductive part, production method for electronic component including conductive part, production method for product made from electronic component including conductive part, conductive part, electronic component including conductive part, and product incorporating electronic component including conductive part

Info

Publication number: WO2022118517A1
Application number: PCT/JP2021/033122
Authority: WO
Inventors: 大輔田ノ岡
Original assignee: 株式会社ブイ・テクノロジー
Priority date: 2020-12-01
Filing date: 2021-09-09
Publication date: 2022-06-09
Also published as: CN116569660A; JP2022087629A; TW202239282A; KR20230113533A

Abstract

Provided is a production method for simply forming a conductive part between a conductor that has an insulating layer at the surface thereof and another conductor. The present invention is a production method for a conductive part that includes a first step for layering a second conductor on a first conductor that has an insulating layer at the surface thereof and a second step for fusing the second conductor and the first conductor, including the insulating layer, to form a fused region and forming a hole that is surrounded by the fused region in the center of the fused region.

Description

Manufacturing method of conductive part, manufacturing method of electronic parts including conductive part, manufacturing method of product assembled with electronic parts including conductive part, conductive part, electronic part having conductive part, product incorporating electronic parts including conductive part

The present invention relates to a method for manufacturing a conductive structure using a calcined metal ink using a metal ink and a conductive structure.

Electronic components with conductors as conductors are made on the substrate. There are various materials for the conductor, and for example, titanium, aluminum, and an alloy thereof, which form a nanometer-order natural oxide layer on the surface of the conductor, may be used as the conductor material. These metals are extremely susceptible to oxidation in the atmosphere and form a natural oxide layer. The natural oxide layer is an insulator, and all parts that come into contact with the atmosphere are covered with the natural oxide layer. Further, instead of the natural oxide layer, an insulating layer such as SiO, SiN, and SiON may be formed by a plasma CVD method on a wiring layer such as aluminum as in Patent Document 2. Even if you try to energize between the two by stacking another wiring on the wiring or electrode that has a natural oxide layer or insulating layer on the surface, simply stacking it will prevent it from being energized by the natural oxide layer or insulating layer. Cannot (does not become a conductive part).
Therefore, as in Patent Document 1, the natural oxide layer is physically destroyed by scratching with a polishing needle, and another conducting wire is overlapped to form a conductive portion.

Japanese Unexamined Patent Publication No. 2000-22306 Patent No. 6711614

However, physical operations such as scratching with a polishing needle become more difficult as the conductor becomes thinner, and workability deteriorates. Moreover, even if the natural oxide layer is destroyed and the metal is exposed, titanium and aluminum are easily oxidized in the atmosphere, and the natural oxide layer is formed again in an extremely short time. Therefore, it is difficult to surely form a conductive portion having conductivity.
The same applies to the insulating layer coated on the surface of the metal wiring, and it is necessary to remove the insulating layer in advance when another wiring is overlapped.

It is an object (problem) of the present invention to provide a manufacturing method for simply forming a conductive portion between a conductor having an insulating layer on the surface and another conductor, and to provide a new conductive portion.

The present invention comprises a first step of laminating a second conductor on a first conductor having an insulating layer on its surface, and the first conductor and the second conductor including the insulating layer. The problem was solved by using a method for manufacturing a conductive portion, which includes a second step of melting to form a molten region and forming a hole surrounded by the molten region in the center of the molten region.

Further, another aspect of the present invention includes a first conductor, a second conductor, and a molten region, the first conductor has an insulating layer on the surface, and the second conductor has a surface. The melted region is laminated on the first conductor, and the melted region is a region where the first conductor and the second conductor including the insulating layer are melted, and the melted region is located in the center of the melted region. The problem was solved by using a conductive portion characterized by having a hole surrounded by a region.

It was possible to simply create a conductive part with conductivity between a conductor having an insulating layer on its surface and another conductor layered on it.

Explanatory drawing of the firing process of metal ink. (A) A conceptual diagram of a firing process of a firing metal ink conductor by scanning a firing laser. (B) Enlarged view of metal ink. (C) Enlarged view of fired metal ink. Explanatory drawing of melting process. (A) Cross-sectional view of a fired metal ink conductor obtained by firing metal ink. (B) Cross-sectional view of a state in which a melting region is created by a melting laser. (C) is a cross-sectional view when the pulse energy of the melting laser is changed and applied to three places, and the depth affected by the melting laser is changed. Explanatory drawing of the range in which heat affects as the irradiation process progresses when laser irradiation is performed using a welding laser that does not form holes. (B) Phase diagram in which the molten region does not extend to the natural oxide layer. (C) A phase diagram in which the molten region exceeds the natural oxide layer. Conductivity test results. A photo of the conductive part. (A) Scanning electron micrograph of a cross section of a conductive portion. (B) Explanatory view of the scanning electron micrograph of FIG. 5 (A). Explanatory drawing of Example 2. FIG. (A) A plan view of a TFT liquid crystal panel. (B) An enlarged view of the detour circuit of FIG. 6 (A). Sectional drawing of the conductive part of Example 3. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different figures indicate parts having the same function, and duplicate description in each figure will be omitted as appropriate. Also, some drawings are intentionally deformed for illustration purposes and are not drawn to the correct scale.

[Distinguishing before and after firing metal ink]
Hereinafter, the metal ink before firing is simply referred to as "metal ink", and the metal ink after firing is referred to as "firing metal ink".

[conductor]
The term "conductor" includes wiring and electrodes.

[Meaning of parentheses attached to terms]
In addition, although it may be described as "fired metal ink conductor (second conductor)", the term in parentheses (second conductor) is a term used in the corresponding claims. show.

[Meaning of insulating layer]
The insulating layer includes a natural oxide layer (insulating layer) formed by natural oxidation on the surface of a metal conductor (first conductor) made of aluminum or the like as a main raw material.
The insulating layer includes not only natural oxidation but also those made by artificial treatment. For example, a metal conductor (first conductor) coated with an insulating layer made of another material is also included in the present invention.
Further, in the present invention, the insulating layer also includes a layer having a higher electric resistance than the metal conductor (first conductor), such as a stain on the surface of the metal conductor (first conductor). Is done.

[Electronic components]
In the present invention, if some element and another element are connected by a conducting wire, they are included in the "electronic component" of the present invention. For example, the "electronic component" of the present invention also includes a circuit board such as a printed circuit board.

(Example 1)
In Example 1 shown in FIGS. 1 to 5, the first conductor A having the natural oxide layer (insulating layer B) 721 on the surface is a metal conductor 72, and the second conductor C is a fired metal ink conductor 27. This is an example of forming a conductive portion 9 between both conductors. Neither the first conductor A nor the second conductor C is limited in terms of the material thereof, but Example 1 is an example in which the metal ink 2 is used for the second conductor C. This is to explain an embodiment in which the metal ink 2 is used for repairing a disconnection or the like. For example, the wiring of the circuit board of a flat panel display may be broken due to dust or dirt adhering to the board during the manufacturing process. In such a case, it can be repaired by forming a detour circuit of the metal ink 2 as the second conductor C between the first conductors A before and after the disconnection.
Example 1 shows an example, and the present invention does not exclude the use of a second conductor C made of a material different from that of the metal ink.

[Insulation layer]
The metal conductor (first conductor A) 72 is mainly composed of a metal such as aluminum or titanium that naturally oxidizes in the atmosphere to form a natural oxide layer (insulating layer B) 721 on the surface.

[Metal ink application process]
FIG. 1 is an explanatory diagram of a firing process of the metal ink 2. FIG. 1A is a conceptual diagram of a firing process of a firing metal ink conductor (second conductor C) 27 by scanning with a firing laser 3. A metal conductor (first conductor A) 72 is disposed on the substrate 7. The metal conducting wire (first conductor A) 72 is a conducting wire containing aluminum as a main component, and a natural oxide layer (insulating layer B) 721 on the order of several nanometers is formed on the surface thereof. Next, the metal ink 2 is applied onto the natural oxide layer (insulating layer B) 721 of the metal conductor (first conductor A).

[Metal ink firing process]
FIG. 1B is an enlarged view of the metal ink 2. The metal ink 2 is obtained by converting highly conductive metals such as gold, silver, and copper into nanoparticles and dispersing them in an organic solvent 26. The melting point of metal drops dramatically as it becomes nanoparticles. The organic substance 25 is adsorbed on the surface of the metal nanoparticles 24, and the organic substances 25 disperse the metal nanoparticles 24 in the organic solvent 26 without aggregating them.

When the metal ink 2 is heated by irradiating it with a firing laser 3 or infrared rays, the organic solvent 26 evaporates, the organic matter 25 on the surface of the metal nanoparticles 24 is desorbed, and the metal nanoparticles 24 agglomerate and melt. It becomes a metal block and becomes conductive. The heating means for firing is appropriate.
In Example 1, a firing laser 3 was used for firing. The absorption wavelength of the metal ink 2 varies depending on the type and particle size of the metal, but is around 400 nm in the metal ink 2 containing the metal nanoparticles 24 containing silver as a main component having a particle size of 20 nm used in Example 1. As the firing laser 3 used in Example 1, a continuously oscillating semiconductor laser having a wavelength near the absorption wavelength was used.

FIG. 1C is an enlarged view of the fired metal ink conductor wire (second conductor C) 27, and it can be seen that the metal nanoparticles 24 are fused to each other to form a metal lump. Only the portion irradiated with the firing laser 3 becomes the fired metal ink conductor wire (second conductor C) 27, and becomes the fired metal ink conductor wire (second conductor C) 27 having conductivity.
As shown in FIG. 1A, the firing laser 3 is scanned left and right along the metal ink 2 as shown by an arrow, fires the metal ink 2, and the lower metal conductor (first conductor A) 72. A fired metal ink lead wire (second conductor C) 27 is laminated on the top.

The [metal ink coating step] and the [metal ink firing step] are combined, and (first step) firing is performed on a metal conductor (first conductor A) 721 having a natural oxide layer (insulating layer B) 721 on the surface. This is a step of laminating the metal ink conductor wire (second conductor C) 27.

In terms of structure, the laminated structure includes a metal conductor (first conductor A) 72 and a fired metal ink conductor (second conductor C) 27, and the metal conductor (first conductor A) 72 is A natural oxide layer (insulation layer B) 721 is provided on the surface thereof, and the fired metal ink conductor (second conductor C) 27 is a natural oxide layer (insulation layer B) of the metal conductor (first conductor A) 72. ) It will be laminated on 721.

[Melting process]
FIG. 2 is an explanatory diagram of the melting process. FIG. 2A is a cross-sectional view of a fired metal ink conductor 27 obtained by firing the metal ink 2. FIG. 2A shows a state in which firing is completed in the above-mentioned [metal ink firing step].
At this point, the natural oxide layer (insulating layer B) 721 is sandwiched between the metal conductor (first conductor A) 72 and the fired metal ink conductor (second conductor C) 27. , There is not enough conductivity to function as the conductive portion 9.

FIG. 2B is a cross-sectional view of a state in which the melting region 8 is created by the melting laser 4. The output of the melting laser 4 may vary depending on the thickness of the metal conductor (first conductor A) 72 and the fired metal ink conductor (second conductor C) 27, the type of metal, and the like. It is not preferable that the influence of the melting laser 4 extends to the substrate 7, and it is preferable that the output affects at least the natural oxide layer (insulating layer B) 721. More preferably, the output extends beyond the natural oxide layer (insulating layer B) 721 to the metal conductor (first conductor A) 72.

The melting laser 4 destroys the natural oxide layer (insulating layer B) 721, and silver derived from the fired metal ink conductor (second conductor C) 27 and aluminum derived from the metal conductor (first conductor A) 72. In addition, a molten region 8 in which aluminum oxide derived from the natural oxide layer (insulating layer B) 721 is mixed is formed.

As shown in the figure, a hole 74 that is a trace of metal evaporation is opened in the central portion where the melting laser 4 hits. The molten region 8 indicated by hatching is formed on the inner wall portion of the hole 74. The molten region 8 contains a large amount of highly conductive aluminum and silver, and only a few nanometers of natural oxide layer (insulating layer B) 721 is mixed, so that the region has significantly high conductivity. Become. As a result, by irradiating the melting laser 4, (second step) the metal conductor (first conductor A) 72 including the natural oxide layer (insulating layer B) 721 and the fired metal ink conductor (second conductivity) are included. The step of melting the body C) 27 to form a molten region and forming a hole 74 surrounded by the molten region 8 at the center of the molten region 8 is performed.

As described above, the molten region 8 in which the natural oxide layer (insulating layer B) 721, the fired metal ink conductor wire (second conductor C) 27, and the metal conductor wire (first conductor A) 72 are melted is formed. A hole 74 surrounded by the melting region 8 is provided at the center of the melting region 8.

[Another aspect of the melting process]
FIG. 2C is a cross-sectional view when the pulse energy of the melting laser 4 is changed and applied to three places, and the depth affected by the melting laser 4 is changed. (Note that FIG. 2 is a conceptual diagram, and low output, medium output, and high output are comparisons of pulse energies in this figure.)

In FIGS. 2C and 2A, a low-power pulse energy melting laser 4 is irradiated. The molten region 8 remains within the range of the fired metal ink conductor (second conductor C) 27, and the metal conductor (first conductor A) 72 and the fired metal ink conductor (second conductor C) 27. No improvement in conductivity can be expected.

Further, in FIGS. 2C and 2B, the melting laser 4 having a medium output pulse energy is irradiated. The effect of the melting laser 4 extends to the vicinity of the natural oxide layer (insulating layer B) 721, and it is between the metal conductor (first conductor A) 72 and the fired metal ink conductor (second conductor C) 27. Although improvement in conductivity can be expected, the thickness of the fired metal ink conductor (second conductor C) 27 is not uniform, so that the conductivity may not be improved as expected.

In FIGS. 2C and 2C, a high-power pulse energy melting laser 4 is irradiated. The molten region 8 is formed beyond the natural oxide layer (insulating layer B) 721 of the metal conductor (first conductor A) 72, and is formed by the metal conductor (first conductor A) 72 and the fired metal ink conductor. The conductivity between (second conductor C) 27 is surely improved.

The metal ink 2 is applied to each portion forming the conductive portion 9, and the coating conditions of the respective portions are not exactly the same. Therefore, the conditions (thickness) of the fired metal ink lead wire (second conductor C) 27 are applied. Etc.) is not constant. Therefore, by irradiating the melting laser 4 at two or more locations, preferably three locations, by changing the pulse energy, it is possible to reliably determine the output suitable for the conditions without conducting an experiment for each conductive portion forming location. Conductivity can be ensured. The pulse width and the number of irradiations may be changed.

In summary, in FIG. 2C, the pulse energy of the melting laser 4 was changed and applied to three points, but it may be two or more points. In order to create a melting region 8 having a different depth of the melting region 8 at two or more locations, another step has a different depth of the melting region at a position different from the melting region formed in the second step, following the second step. A third step of creating a melting region may be added.

Further, since the melting regions are provided at two or more locations and the depths of the melting regions are different from each other, the conductivity can be surely secured.

In the embodiment, the melting laser 4 set so that the hole 74 is formed by the pulse energy is used. By forming a hole 74 surrounded by the melting region 8 at the center of the melting region 8, it is possible to know the depth at which the melting region 8 is formed. Further, by forming the hole 74, heat is released through the hole 74, and the melting region 8 can be quickly cooled. Generally, the thermal energy affects the members in the vicinity of the molten region 8, and particularly when the substrate 7 in which the organic layer or the like is close to the molten region 8 is irradiated with a laser, the organic layer may be altered. However, the melting laser 4 set to form a hole 74 by irradiating a nanosecond pulse laser with a high output as in the present invention forms a minute hole 74 penetrating the natural oxide layer (insulating layer B) 721. do. The heat of the melting region 8 is also dissipated from the hole 74 to increase the cooling rate, and the influence of the heat can be limited to a very small region around the melting region 8.

On the other hand, when the welding laser 41 that does not form the hole 74 is used, the melting region 8 becomes large and the range affected by heat also becomes large.

FIG. 3, which corresponds to a comparative experiment, is an explanatory diagram of a range in which heat is affected as the irradiation process progresses when laser irradiation is performed using a welding laser 41 that does not form a hole 74. FIG. 3A is a state diagram immediately after irradiation, FIG. 3B is a state diagram in which the molten region 8 does not extend to the natural oxide layer (insulating layer B) 721, and FIG. 3C is a molten region. 8 is a phase diagram in which 8 exceeds the natural oxide layer (insulation layer B) 721.

As shown in FIG. 3A, the melting region 8 immediately after irradiation is small, but heat is diffused by heat conduction from the irradiation region of the welding laser 41 that does not form the hole 74. When the irradiation is continued, the molten region 8 gradually expands as shown in FIG. 3 (B). When further irradiation is continued, heat conduction continues, and the molten region 8 gradually expands, forming a molten region 8 larger than the irradiation region of the welding laser 41 that does not form a hole 74 as shown in FIG. 3C, and a natural oxide layer is formed. (Insulation layer B) Melts 721. The temperature of the melting region 8 reaches the melting point of the metal and is extremely high, and the periphery of the melting region 8 is a region 412 affected by heat due to heat conduction. At this time, heat is dissipated only from the surface of the fired metal ink conductor (second conductor C) 27, and the larger the volume of the molten region 8, the more the heat dissipated in proportion to the surface area cannot catch up. The region 412 affected by heat is greatly expanded by the high-temperature metal accumulated in the molten region 8 having an increased volume.

In the first embodiment, since the hole 74 is formed in the center of the molten region 8 as shown in FIG. 2, the metal in the molten region 8 is cooled quickly.
Using the melting laser 4 that forms the hole 74 in this way can significantly reduce the area 412 affected by heat as compared to using the welding laser 41 that does not form the hole 74.

Hereinafter, experimental examples of the present invention will be described.
(Experiment 1: Experiment showing the relationship between electrical resistance and pulse energy)
Experiment 1 is an experiment to investigate how the electric resistance changes before and after the natural oxide layer (insulating layer B) 721 is destroyed by changing the depth of the molten region 8. In Experiment 1, as a sample for irradiation of the welding laser 4, a sample in which the metal ink 2 was applied onto the metal lead wire 72 on the substrate 7 and fired to form the fired metal ink lead wire 27 was prepared. Then, the sample was irradiated with the melting laser 4 under different conditions. In order to change the depth of the melting region 8 formed by the melting laser 4, the pulse energy of the melting laser 4 is changed under four conditions of 100, 200, 250, and 300 μJ. In addition, the conditions other than the pulse energy are the same.

The conditions of Experiment 1 will be described.
(1) Laser for melting 4
Wavelength 532nm
Pulse width 10ns
Number of pulses 1 time Melting processing set size 1 μm x 1 μm
Experiment with pulse energy of 100, 200, 250, 300 μJ (see Fig. 4)
(2) Metal conductor (first conductor A) 72
Metal type Aluminum wiring width ・ 5 μm
(3) Fired metal ink conductor (second conductor C) 27
Metal type Silver (nanoparticles)
Wiring thickness 0.4 μm
Under the above experimental conditions, a sample in which the pulse energy of the melting laser 4 was changed was prepared, and the electric resistance between the metal conductor (first conductor A) 72 and the fired metal ink conductor (second conductor C) 27 was prepared. Was measured. The result is shown in FIG.

At a pulse energy of 100 μJ, the electrical resistance was 340 Ω on average, and there was no improvement in conductivity compared to before irradiation with the melting laser 4. It is presumed that the influence of the melting laser 4 is limited to the range of the fired metal ink lead wire (second conductor C) 27 as shown in FIGS. 2C and 2A.

At a pulse energy of 200 μJ, the electrical resistance was 50 Ω on average, and a significant improvement in conductivity was observed. It is presumed that the influence of the melting laser 4 remains in the vicinity of the natural oxide layer (insulating layer B) 721 as shown in FIGS. 2 (C) and 2 (b).

At pulse energies of 250 μJ and 300 μJ, the average electrical resistance dropped sharply to near 0Ω. It is presumed that the natural oxide layer (insulating layer B) 721 is melted, and the influence of the melting laser 4 is exerted on the metal conductor (first conductor A) 72 as shown in FIGS. 2 (C) and 2 (c). It is presumed that it has reached. At the pulse energy of 200 μJ, the error bar (3σ) remained about 30 Ω on one side and about 60 Ω on both sides, and there was a large variation in the observed electrical resistance. However, at the pulse energies of 250 μJ and 300 μJ, the error bar (3σ) was 2 to 2. It is 3Ω.

This indicates that the influence of the melting laser 4 has reached the point where the conductivity can be surely secured. The electrical resistance is sufficiently small, indicating that the conductive portion 9 is stably formed with little variation.

(Experiment 2: Confirmation of molten region)
In order to confirm the existence of the molten region 8, an experiment 2 was conducted in which a scanning electron microscope image of the conductive portion 9 was taken.
5A and 5B are scanning electron micrographs of the conductive portion 9, FIG. 5A is an explanatory view of the scanning electron micrograph of the conductive portion 9, and FIG. 5B is an explanatory diagram of the scanning electron micrograph of FIG. 5A. Is.

The imaging sample was prepared as follows and photographed.
(1) The substrate 7 having the conductive portion 9 made as described above was used as a sample, and was coated with a protective film 73 as a pretreatment for performing the next electron beam cutting.
(2) The entire substrate 7 was cut with an electron beam, and a cross section was cut out.
(3) The sample prepared as described above was photographed with a scanning electron microscope from an angle at which the cross section can be seen.

The hatched protective film 73 of FIG. 5B is coated at the time of sample preparation and does not exist in the original conductive portion 9.
There is a natural oxide layer (insulating layer B) 721 on the surface of the metal conductor (first conductor A) 72, but it is several nanometers thick and is not shown at this magnification.

A hole 74 is formed in the region irradiated with the melting laser 4. On the side of the hole 74, the boundary between the calcined metal ink conductor (second conductor C) 27 and the metal conductor (first conductor A) 72, which should originally exist, is blurred or completely disappeared. From this, the metal conductor (first conductor A) 72 including the natural oxide layer (insulation layer B) 721 and the fired metal ink conductor (second conductor C) 27 are melted to form a melted region 8. You can see that there is.

(Summary of Experiment 1 and Experiment 2)
From the above experiments, by irradiating the melting laser 4, the metal conductor (first conductor A) 72 including the natural oxide layer (insulating layer B) 721 and the fired metal ink conductor (second conductor C) 27 are formed. It was confirmed that the molten region 8 was formed by melting. Then, due to the irradiation of the melting laser 4, the electric resistance between the metal conductor (first conductor A) 72 and the fired metal ink conductor (second conductor C) 27 is remarkably reduced, and the electric resistance value varies. It was confirmed that less results were obtained. It can be said that the present invention can be put into practical use because the electric resistance value has little variation.

(Example 2)
Example 2 is an application example of the present invention. 6A and 6B are explanatory views of the second embodiment, FIG. 6A is a plan view of a substrate 7 of a TFT liquid crystal panel, and FIG. 6B is an enlarged view of a detour circuit provided in FIG. 6A. be.

A field effect transistor 12 is mounted on a substrate 7 of a TFT liquid crystal panel of an LCD (liquid crystal display), and a metal conducting wire (first conductor A) 72 containing aluminum as a main component is wired. One of the wirings has a defect (disconnection) 722, which is usually discarded as a defective product.

The substrate 7 having the defect (disconnection) 722 is repaired by the detour circuit 76 created by the fired metal ink conductor wire (second conductor C) 27, whereby the product yield is improved.

There are various possible causes for the defect (disconnection) 722, but the main cause is the adhesion of dust. It is possible to connect the defect (disconnection) 722 directly and linearly at the shortest distance, but since there is a possibility that dust or the like may remain, the detour circuit 76 is intentionally used. Of course, the defect (disconnection) 722 may be directly and linearly connected at the shortest distance for repair.

The detour circuit 76 using the silver metal ink 2 is fired by a firing laser 3 (not shown) to form a fired metal ink conductor wire (second conductor C) 27.
As a result, in the conductive portion 9, the substrate 7, the metal conductor (first conductor A) 72, the natural oxide layer (insulation layer B) 721, and the fired metal ink conductor (second conductor C) 27 are in this order. The structure is laminated from below.

The melting laser 4 is irradiated to each conductive portion 9 at three locations with different pulse energy intensities. (See Fig. 2 (C))

The conductive portion 9 is formed in the molten region 8 formed around the three holes 74. If any one of the three molten regions 8 in which the intensity of the pulse energy is changed reaches the natural oxide layer (insulating layer B) 721, the metal conductor (first conductor A) 72 and the fired metal ink conductor (first) The electrical resistance between the conductors C) 27 of 2 is reduced to the extent that it does not affect the operation of the TFT liquid crystal panel.
Further, since the hole 74 surrounded by the melting region 8 is formed in the center of the melting region 8, the metal melted in the melting region 8 releases heat from the hole 74 and is quickly cooled, so that the metal in the melting region 8 is cooled quickly. The influence of heat on the surroundings is reduced.

In the present invention, the substrate (electronic component) of the TFT liquid crystal panel can be used in the manufacturing method as in the second embodiment.
Further, the present invention provides a molten region 8 in which the metal conductor (first conductor A) 72 including the natural oxide layer (insulation layer B) 721 and the fired metal ink conductor (second conductor C) 27 are melted. It is possible to provide a substrate (electronic component) of a TFT liquid crystal panel having the obtained conductive portion 9.

Further, it can be used as a method for manufacturing a product called a TFT liquid crystal panel by assembling the substrate (electronic component) of the TFT liquid crystal panel provided as described above with other parts.
Further, it is possible to provide a product called a liquid crystal display by assembling the TFT liquid crystal panel (electronic component) provided as described above with other components.
Since the details and manufacturing method of the TFT liquid crystal panel and the liquid crystal display technique are widely known, they will not be described here.

(Example 3)
FIG. 7 is a cross-sectional view of the conductive portion 9 of the third embodiment.
Examples 1 and 2 were examples in which the natural oxide layer 721 was used as the insulating layer B. Example 3 is an embodiment in which an insulating layer B is artificially formed on the surface of a metal conductor (first conductor A). Further, the second conductor C does not have to be a fired metal ink lead wire. Further, the same metal material may be used for the first conductor A and the second conductor C.

As one of the examples, an example of the laminated circuit board 5 is shown. The laminated circuit board 5 has a first conductor A, an insulating layer B, a second conductor C, an insulating layer B, a first conductor A, an insulating layer B, and a second conductor C. A large number of conductors are laminated with the insulating layer B interposed therebetween.

By irradiating the laminated conductor with the melting laser 4, the conductive portion 9 is formed in the melting region 8 in which the first conductor A, the second conductor C, and the insulating layer B are melted. To. The melting region 8 becomes the conductive portion 9, and all the laminated conductors can be made conductive.

Although Examples 1 to 3 according to the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to these embodiments and deviates from the gist of the present invention. It is included in the present invention even if there is a design change to the extent that it does not occur.
Further, each of the above-mentioned embodiments can be combined by diverting the techniques of each other as long as there is no particular contradiction or problem in the purpose and configuration thereof.

A First conductor B Insulation layer C Second conductor 2 Metal ink 24 Metal nanoparticles 25 Organic matter 26 Organic solvent 27 Calcined metal ink conductor (second conductor)
3 Laser for firing 4 Laser for melting 41 Laser for welding 412 Area affected by heat 5 Laminated circuit board 7 Board 72 Metal conductor (first conductor)
721 Natural oxide layer (insulation layer)
722 Defect (disconnection)
73 Protective film 74 Hole 75 Field effect transistor 76 Detour circuit 8 Melting region 9 Conductive part

Claims

The first step of laminating the second conductor on the first conductor having an insulating layer on the surface, and
A second step of melting the first conductor and the second conductor including the insulating layer to form a molten region and forming a hole surrounded by the molten region in the center of the molten region. A method for manufacturing a conductive part, including.
Following the second step,
The method for manufacturing a conductive portion according to claim 1, further comprising a third step of forming another melting region having a different depth of the melting region at a position different from the melting region formed in the second step.
The insulating layer is a natural oxide layer obtained by oxidizing the metal of the first conductor.
The method for manufacturing a conductive portion according to any one of claims 1 or 2, wherein the second conductor is a fired metal ink conducting wire obtained by firing metal ink.
A method for manufacturing an electronic component, wherein the first conductor is arranged on a substrate, and the conductive portion according to any one of claims 1 to 3 is formed on the substrate.
A method for manufacturing a product, wherein the electronic component according to claim 4 is assembled with another electronic component to make a product.
With a first conductor, a second conductor and a melting region,
The first conductor has an insulating layer on its surface and has an insulating layer.
The second conductor is laminated on the first conductor.
The melted region is a region where the first conductor and the second conductor, including the insulating layer, are melted, and has a hole surrounded by the melted region in the center of the melted region. Conductive part characterized by being present.
The conductive portion according to claim 6, wherein the melting region is provided at two or more locations, and the depths of the melting regions are different from each other.
The insulating layer is a natural oxide layer derived from the metal of the first conductor.
The conductive portion according to any one of claims 6 or 7, wherein the second conductor is a fired metal ink conducting wire obtained by firing metal ink.
The first conductor is an electronic component that is arranged on a substrate and has a conductive portion according to any one of claims 6 to 7.
A product incorporating the electronic components according to claim 9.