JP2019140283A - Metal wiring manufacturing method and metal wiring manufacturing apparatus - Google Patents

Abstract

To irradiate metal particles with light with the output increased to a value suitable for sintering.SOLUTION: In a manufacturing method of metal wiring (1, 23), metal particles are sintered by controlling respective light beams (53, 54) emitted from a plurality of light sources (51, 52) such that the light beams are focused on a layer to be treated (11) including the metal particles (12). It is preferable to focus the light beams on the layer to be processed by using a focusing control unit (60) disposed between the light source and the layer to be processed including the metal particles. With this configuration, since a plurality of light beams can be focused, the metal particles can be irradiated with light beams in a state where the output is increased to a value suitable for sintering. Therefore, the metal particles can be effectively sintered to obtain low resistance metal wiring.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a metal wiring manufacturing method and a generic wiring manufacturing apparatus.

  The circuit board has a structure in which conductive metal wiring is provided on the board. In the method of manufacturing a circuit board, first, a photoresist is applied on a substrate on which a metal foil is bonded. Next, the photoresist is exposed and developed to obtain a negative shape of a desired circuit pattern, and a pattern is formed by removing a portion of the metal foil not covered with the photoresist by chemical etching. Thereby, a high-performance circuit board can be manufactured. However, this method has a number of steps, is complicated, and has disadvantages such as requiring a photoresist material.

  Direct wiring printing technology (hereinafter referred to as PE (printed electronics) method) that directly prints a desired wiring pattern on a substrate with a dispersion in which metal fine particles are dispersed has attracted attention. This technique does not require the use of a photoresist material, and the number of processes is small, so that the productivity is extremely high.

  As such a dispersion, metal ink is known (see, for example, Patent Document 1). The metal ink is a dispersion in which ultrafine metal particles having an average particle diameter of several to several tens of nanometers are dispersed in a dispersion medium. When the metal ink is applied to the substrate and dried, and then heat-treated, the metal ink sinters at a temperature lower than the melting point of the metal due to a melting point drop unique to the ultrafine metal particles. ) Can be formed. A metal film obtained using metal ink has a thin film thickness and is close to a metal foil.

  For the heat treatment of the metal ink, plasma treatment, irradiation with laser light or flash light is performed. By heat-treating the metal ink applied to the substrate, the metal superparticles are sintered together to obtain electrical conductivity. By performing heat treatment of the metal ink with laser light, patterning and sintering of the metal fine particles can be performed at a time.

International Publication No. 2003/051562

  By the way, in the irradiation of the light to the metal ink for sintering, there exists an optimal wavelength according to the light absorption wavelength of a metal particle. Since the wavelength can be freely selected by performing the sintering of the metal particles with the laser beam, the light having a wavelength suitable for the sintering can be irradiated, and the metal particles can be effectively sintered. However, when light having an optimum wavelength is selected, the output necessary for sintering the metal particles may not be obtained, and sintering may be insufficient.

  This invention is made | formed in view of this point, and provides the manufacturing method and metal wiring manufacturing apparatus of a metal wiring which can irradiate a metal particle with a light ray in the state which raised the output to the value suitable for sintering. One of the purposes.

  As a result of intensive studies to solve the above problems, the present inventor has completed the present invention.

  That is, in the metal wiring manufacturing method of one embodiment of the present invention, the metal particles are sintered by controlling each light beam emitted from a plurality of light sources so as to be focused on the layer to be processed including the metal particles. It is characterized by.

  With this configuration, since a plurality of light beams can be focused, the metal particles can be irradiated with light in a state where the output is increased to a value suitable for sintering.

  In the metal wiring manufacturing method of one embodiment of the present invention, it is preferable that the light beam is focused on the processing layer using a focusing control unit disposed between the light source and the processing layer. . With this configuration, a plurality of light beams can be easily and appropriately focused on the layer to be processed including metal particles.

  In the metal wiring manufacturing method of one embodiment of the present invention, the metal particles preferably contain at least one selected from the group consisting of copper, silver, gold, and aluminum.

  In the metal wiring manufacturing method of one embodiment of the present invention, the metal particles are preferably copper oxide particles. Thus, reduction can be facilitated by using copper oxide particles as compared with other metal oxide particles. Further, the copper particles are sintered together with the reduction to form a dense random chain between the copper particles, and desired conductivity can be obtained, so that a metal wiring with low resistivity can be formed. Moreover, compared with silver particle, cost can be reduced and it is advantageous with respect to migration.

  In the metal wiring manufacturing method of one embodiment of the present invention, it is preferable that the layer to be processed is formed using a dispersion containing the copper oxide particles and a dispersant.

  A metal wiring manufacturing apparatus according to an aspect of the present invention includes a plurality of light sources, and a focusing control unit that controls each light beam emitted from the plurality of light sources to focus on a processing layer including metal particles. It is characterized by that.

  In the metal wiring manufacturing method or the metal wiring manufacturing apparatus of one aspect of the present invention, the focusing control unit transmits at least one of the light beams, reflects the remaining light beams, and focuses the light on the layer to be processed. Is preferred. With this configuration, it is possible to irradiate the layer to be processed including metal particles in a state where a plurality of light beams are superimposed on the same optical axis. Thereby, the output on the light beam can be effectively increased, and the firing of the metal particles can be appropriately promoted.

  In the metal wiring manufacturing method or the metal wiring manufacturing apparatus according to one aspect of the present invention, the focusing control unit is preferably a wavelength selection member.

  In the metal wiring manufacturing method or the metal wiring manufacturing apparatus according to one aspect of the present invention, the focusing control unit is preferably a reflective polarizing plate.

  In the metal wiring manufacturing method or the metal wiring manufacturing apparatus of one aspect of the present invention, in the focusing control unit having an incident surface and an output surface, a plurality of the light beams are incident on the incident surface and are emitted from the output surface. And focusing on the layer to be treated. With this configuration, a plurality of light beams can be focused with a simple configuration, and the output can be effectively increased.

  In the metal wiring manufacturing method or the metal wiring manufacturing apparatus according to one aspect of the present invention, the focusing control unit is preferably a lens.

  In the metal wiring manufacturing method or the metal wiring manufacturing apparatus of one embodiment of the present invention, the light beam is preferably a laser beam having a center wavelength of 355 nm to 550 nm. With this configuration, for example, laser light having a wavelength suitable for sintering metal particles such as copper, silver, gold, and aluminum is irradiated at an output suitable for sintering metal particles such as copper, silver, gold, and aluminum. Thus, metal particles such as copper, silver, gold, and aluminum can be effectively sintered.

  In the metal wiring manufacturing method or the metal wiring manufacturing apparatus of one embodiment of the present invention, it is preferable that the center wavelength is 400 nm or more and 532 nm or less. With this configuration, it is possible to effectively sinter the copper particles by irradiating laser light having a wavelength suitable for sintering the copper oxide particles with an output suitable for sintering the copper particles.

  According to the metal wiring manufacturing method and metal wiring manufacturing apparatus of the present invention, it is possible to irradiate the metal particles with light in a state where the output is increased to a value suitable for sintering.

It is the schematic diagram which simplified and showed a part of metal wiring manufacturing apparatus for demonstrating the manufacturing method of the metal wiring which concerns on this Embodiment. It is a schematic diagram which shows an example of the focusing control part applied to the manufacturing method and metal wiring manufacturing apparatus which concern on this Embodiment. It is a schematic diagram which shows the relationship between the copper oxide particle and phosphate ester salt in the to-be-processed layer which concerns on this Embodiment. It is a schematic diagram which shows the whole structure of the metal wiring manufacturing apparatus concerning this Embodiment. It is a schematic diagram which shows an example of the metal wiring which concerns on this Embodiment, and the scanning of a light ray. It is a cross-sectional schematic diagram which shows the structure with metal wiring which concerns on this Embodiment. It is explanatory drawing which shows each process of the manufacturing method of the structure with metal wiring which concerns on this Embodiment.

  Hereinafter, an embodiment of the present invention (hereinafter abbreviated as “embodiment”) will be described in detail.

  For a metal ink using metal particles such as copper, silver, gold, and aluminum, it is required to use light having an optimum wavelength according to the light absorption wavelength of the metal particles. At the same time, an optimum output for firing is required. For example, for a layer to be treated containing copper oxide particles, an output of about 10 to 20 W is required with a continuous wave (CW, Continuous Wave) of 400 nm or more and 532 nm or less. On the other hand, it is difficult to obtain light having an optimum wavelength and optimum output with a single light source. Therefore, in the present embodiment, by converging a plurality of light beams, a light beam having a wavelength suitable for sintering of the metal particles can be applied to the processing layer including the metal particles with an output suitable for sintering. I made it.

<Manufacturing method of metal wiring>
Hereinafter, the manufacturing method of the metal wiring of this Embodiment is demonstrated. FIG. 1 is a schematic diagram showing a part of a metal wiring manufacturing apparatus in a simplified manner for explaining the metal wiring manufacturing method according to the present embodiment. FIG. 2 is a schematic diagram illustrating an example of a focusing control unit applied to the metal wiring manufacturing method and the metal wiring manufacturing apparatus according to the present embodiment.

  The method of manufacturing a metal wiring according to the present embodiment is characterized in that the metal particles are sintered by controlling each light beam emitted from a plurality of light sources so as to be focused on the layer to be processed including the metal particles. . As shown in FIG. 1, a plurality of laser light sources 51 and 52 are used to focus laser beams 53 and 54 and irradiate the layer 11 to be processed.

  Thus, in the present embodiment, since the metal particles are sintered in a state where a plurality of light beams are focused, the output of the focused light can be increased even if the output of each light beam is weak. Accordingly, the metal particles can be irradiated with light in a state where the output is increased to a value suitable for sintering, and the metal particles are effectively sintered. The layer to be treated includes an insulator in addition to the metal particles, but by increasing the output, the insulator can be appropriately eliminated, can be sufficiently sintered, and a low-resistance metal wiring can be obtained. .

  It is preferable to arrange the focusing control unit 60 between the laser light sources 51 and 52 and the layer to be processed 11. Thereby, the laser beams 53 and 54 from the laser light sources 51 and 52 can be appropriately and easily focused. The focusing control unit 60 can be configured to superimpose a plurality of lights on the same optical axis (FIGS. 2A and 2B) or to focus a plurality of lights at the position of the processing layer (FIG. 2C). Hereinafter, the focusing control unit 60 will be described in detail.

(First embodiment: wavelength selection member)
In FIG. 2A, the wavelength selection member 61 is used as the focusing control unit 60. The wavelength selection member 61 reflects light in a specific wavelength range and transmits light in other wavelength ranges. By the wavelength selection member 61, one of the laser beams 53 and 54 can be transmitted, the other laser beam 54 can be reflected, and the plurality of laser beams 53 and 54 can be superimposed on the same optical axis.

  As shown in FIG. 2A, when the focusing control unit 60 is the wavelength selection member 61, the wavelengths of the laser beams 53 and 54 emitted from the laser light sources 51 and 52 are different. That is, the wavelength of the laser light 53 emitted from the laser light source 51 and the wavelength of the laser light 54 emitted from the laser light source 52 are different. For example, the wavelength selection member 61 transmits the laser light 53 and Reflects laser light 54 of different wavelengths. Thereby, the laser beams 53 and 54 having different wavelength ranges can be overlapped on the same optical axis and focused on the processing target layer 11. As the wavelength selection member 61, a wavelength selection mirror, a wavelength selection prism, or the like can be used. A dichroic mirror or the like can be used as the wavelength selection mirror, and a dichroic prism or the like can be used as the wavelength selection prism.

(Second embodiment: reflective polarizing plate)
In FIG. 2B, a reflective polarizing plate 62 is used as the focusing control unit 60. The reflective polarizing plate 62 transmits either the S-polarized light or the P-polarized light and reflects the other. Thereby, the laser beams 53 and 54 having different polarizations can be converged at the position of the reflective polarizing plate 62, and the light can be collected on the same optical axis. When the reflective polarizing plate 62 is used, the wavelengths of the plurality of laser beams 53 and 54 may be the same or different from each other. As described above, when the reflective polarizing plate 62 is used, a plurality of lights can be superimposed on the same optical axis and focused on the processing layer 11 regardless of the wavelengths of the laser beams 53 and 54. For this reason, in the structure of FIG. 2B, the output of the light of a certain specific wavelength can be improved effectively.

  As the reflective polarizing plate 62, for example, a wire grid polarizer can be used. For example, if the polarization of the plurality of light beams is different from each other, the reflective polarizing plate 62 can superimpose the plurality of light beams on the same optical axis even when the wavelengths of the plurality of light beams are different from each other.

(Third embodiment: lens)
In addition, the focusing control unit 60 may be configured such that an incident surface and an exit surface are formed, and a plurality of light beams are incident on the entrance surface, emitted from the exit surface, and focused on the processing target layer 11. In this embodiment, the plurality of lights can be controlled to be refracted at the position of the focusing control unit 60 and to be focused at the position of the processing target layer 11. In such a configuration, a plurality of light sources can be arranged on the incident surface side, and a plurality of light beams can be focused with a simple configuration. For this reason, the number of light sources can be easily increased, and the output can be effectively increased.

  An example of such a focusing control unit 60 is a lens 63 as shown in FIG. 2C. As shown in FIG. 2C, the lens 63 has an entrance surface 63a and an exit surface 63b. The plurality of light sources are arranged on the incident surface 63 a side of the lens 63. Accordingly, the plurality of laser beams 53 and 54 can be incident on the common incident surface 63a and can be emitted from the common emission surface 63b. The laser beams 53 and 54 can be controlled to be refracted at the position of the lens 63 and to be focused at the position of the layer 11 to be processed. That is, by controlling the distance between the lens 63 and the layer 11 to be processed or by selecting various shapes and types of the lens 63, the plurality of laser beams 53 and 54 are exactly at the position of the layer 11 to be processed. It can be controlled to focus.

  The lens 63 is preferably a convex lens, a concave lens, a concave-convex lens, or the like. For example, a concave lens is more preferable because the optical axis can be easily adjusted. The size of the lens 63 can be adjusted by the number of laser light sources 51 and 52 used. When converging laser light from a plurality of light sources, the size can be increased so that all laser light is incident. .

  In the configuration of FIG. 2C, even if the laser beams 53 and 54 have different wavelengths, the laser beams 53 and 54 having the same wavelength can be appropriately focused through the lens 63. In addition, since the position of the lens 63 can be easily adjusted with respect to the processing layer 11, the focal positions of the focused laser beams 53 and 54 can be adjusted in the processing layer 11.

(Other embodiments)
For example, without using the focusing control unit 60, the inclination of the laser light sources 51 and 52 or the laser light source 51 so that the laser beams 53 and 54 from the plurality of laser light sources 51 and 52 are focused at the position of the processing target layer 11. , 52 and the layer 11 to be processed can be used by a focusing method that appropriately adjusts the distance. In this configuration, since the focusing control 60 is not necessary, the cost can be suppressed. However, since the focusing control unit 60 as shown in FIG. 2 can be used to focus easily and accurately, the focusing control unit 60 is preferably used.

  Further, any one of the focusing control units 60 shown in FIG. 2 can be selected according to various factors such as required output and wavelength. For example, in the configurations of FIGS. 2B and 2C, it is easy to focus light having the same wavelength. Also, a plurality of the focusing control units 60 shown in FIG. 2 can be used. For example, using the reflective polarizing plate 62 shown in FIG. 2B, light superimposed on the same optical axis can be passed through the lens 63 shown in FIG. 2C.

(light source)
In the present embodiment, the light source is not particularly limited, but it is preferable to use laser light sources 51 and 52 as the light source as shown in FIG. Thereby, the wavelength of the laser beam as the light beam can be freely selected in consideration of the light absorption wavelength of the metal particles. In the present embodiment, a plurality of laser light sources are used to focus a plurality of laser beams.

  The laser light sources 51 and 52 have a degree of freedom in selecting the wavelengths of the laser beams 53 and 54 and can be selected in consideration of the light absorption wavelength of the processing target layer 11 and the absorption wavelength of the support 56. Laser types include YAG (yttrium, aluminum, garnet), YVO (yttrium vanadate), Yb (ytterbium), semiconductor laser (GaAs, GaAlAs, GaInAs, GaN, InGaN, AlGaN, etc.), carbon dioxide gas, fiber laser, etc. In addition to the fundamental wave, harmonics may be extracted and used as necessary. It is more preferable to use a semiconductor laser or a second harmonic. Further, the laser beams 53 and 54 can be a pulse wave (Pulsed Operation) or a continuous wave (CW). Thereby, when the to-be-processed layer 11 is a copper oxide ink layer, a copper particle can be sintered effectively. In particular, it is preferable that continuous wave irradiation is performed for sintering of copper particles.

  The number of light sources may be plural, and may be two or three or more. For example, in the configuration using the lens 63 shown in FIG. 2C, two or more light sources can be easily installed on the incident surface 63a side of the lens 63. In addition, for example, two or more wavelength selection members 61 shown in FIG. 2A may be provided as long as laser beams having different wavelengths can be focused, or the laser beams from three or more laser light sources may be focused. . Thereby, since the laser light sources 51 and 52 can be increased and the plurality of laser beams 53 and 54 can be focused, the output of the laser beams 53 and 54 is effectively reduced to a value suitable for sintering of the metal particles of the layer 11 to be processed. Can be increased.

  The number of light sources can be appropriately selected according to the optimum wavelength and the optimum output. For example, for copper oxide ink, a continuous wave of 400 nm to 532 nm and an output of about 10-20 W is required. Since the output of a single light source at the optimum wavelength is several W, the number of light sources is selected so as to satisfy the optimum wavelength and the optimum output. Although not limited, in the case of copper oxide ink, the optimal wavelength and the optimal output can be easily satisfied by setting the number of light sources to 4 or more.

(Emission wavelength)
Although the emission wavelengths of the laser beams 53 and 54 are not particularly limited, the metal wiring manufacturing method of the present embodiment can be preferably applied to light having a central wavelength of 355 nm to 550 nm. By irradiating laser beams 53 and 54 having a wavelength in this range, if the layer 11 to be treated contains metal particles such as copper, silver, gold, and aluminum, the metal particles are sintered. By irradiating laser beams 53 and 54 having a wavelength suitable for the above with an output suitable for sintering these metal particles, the metal particles can be effectively sintered. The emission wavelengths of the laser beams 53 and 54 are preferably such that the center wavelength is not less than 400 nm and not more than 532 nm. Thereby, for example, when the layer to be processed 11 is a copper oxide ink layer, the laser beams 53 and 54 having wavelengths suitable for sintering the copper particles contained in the copper oxide ink layer are suitable for sintering the copper particles. Irradiation with output can effectively sinter copper particles. The wavelengths of the laser beams 53 and 54 are preferably, for example, 355 nm, 405 nm, 445 nm, 450 nm, and 532 nm when the support 56 of the layer to be processed 11 is a resin. As described above, in the present embodiment, when the layer to be processed 11 is a copper oxide ink layer, the laser beams 53 and 54 having a center wavelength suitable for sintering of copper particles of the copper oxide ink layer of 400 nm or more and 532 nm or less are used. Irradiation can be performed at an output suitable for sintering copper particles.

  Further, exposure by beam scanning is possible, and adjustment of the exposure range such as exposure of the entire processing layer or selection of partial exposure is easy. The exposure amount can be adjusted by the light intensity, the light emission time, the light irradiation interval, and the number of times. If the light transmittance of the support 56 is large, it can be applied to a resin substrate having low heat resistance, for example, PET, PEN or paper. Pattern formation with copper oxide ink is possible.

(Processed layer)
Next, the layer to be processed 11 will be described. As described above, the layer 11 to be processed is a layer containing metal particles.

  It is preferable that the metal particle contained in the to-be-processed layer 11 contains at least one selected from the group consisting of copper, silver, gold and aluminum. By using copper, silver, gold, aluminum, or the like as the metal particles, the metal particles can be effectively sintered, so that conductivity can be appropriately obtained.

  Moreover, it is preferable that the metal particle contained in the to-be-processed layer 11 is a metal oxide particle. By irradiating the metal oxide particles with light, the metal oxides can be reduced to form metal particles and the metal particles can be sintered. When the metal particles that are easily oxidized are used as they are, an antioxidant treatment is necessary to prevent the metal particles from being oxidized, and the antioxidant treatment hinders the sintering of the metal particles. By using metal oxide particles, it is not necessary to perform an anti-oxidation treatment that hinders sintering, so that sintering can be promoted.

  The metal oxide particles are preferably copper oxide particles. By using copper oxide particles, reduction can be facilitated as compared with other metal oxide particles. Further, the copper particles are sintered together with the reduction to form a dense random chain between the copper particles, and desired conductivity can be obtained, so that a metal wiring having a low resistivity can be formed. Moreover, compared with silver particle, cost can be reduced and it is advantageous with respect to migration.

  The layer to be treated 11 is preferably a dispersion containing metal particles and a dispersant. The dispersion is preferably formed of a metal ink, and more preferably a copper oxide ink. By using a dispersant in the dispersion, aggregation of metal particles can be suppressed.

  The dispersant preferably contains a phosphorus-containing organic material. By using a phosphorus-containing organic substance as a dispersant, aggregation of metal particles can be effectively suppressed due to a steric hindrance effect. In addition, since the phosphorus-containing organic substance is easily decomposed by heat, a residue of the phosphorus-containing organic substance is hardly left after the metal particles are sintered by irradiation with light, and a metal wiring having a low resistivity can be obtained.

  Next, the case where the layer to be treated containing metal particles is formed from a dispersion (copper oxide ink) containing copper oxide particles and a phosphorus-containing organic substance as a dispersant will be described as an example.

  FIG. 3 is a schematic diagram showing the relationship between the copper oxide particles and the phosphate ester salt in the layer to be treated according to the present embodiment. The to-be-processed layer 11 in FIG. 3 is a layer containing the phosphoric acid ester salt 13 which is an example of the copper oxide particle 12 and phosphorus containing organic substance, and is also called a copper oxide ink layer. As shown in FIG. 3, in the treated layer 11, around the copper oxide particles 12, the phosphate ester salt 13 surrounds the phosphorus 13 a on the inside and the ester salt 13 b on the outside. Since the phosphate ester salt 13 exhibits electrical insulation, electrical continuity between adjacent copper oxide particles 12 is hindered.

  Therefore, since the copper oxide particles 12 are semiconductors and conductive, but are covered with the phosphate ester salt 13 exhibiting electrical insulation, the layer 11 to be treated before firing (described later) has electrical insulation. Insulation between the metal wirings (see FIG. 6 described later) adjacent to both sides of the insulating region 11 can be ensured.

<Application example>
In the metal wiring manufacturing method according to the present embodiment, as an example, the light irradiated to the layer to be processed 11 using copper oxide particles as the metal particles is focused by the lens 62 shown in FIG. 2C. The wavelength of the light at this time is a continuous wave (CW) of 400 to 532 nm, the laser beams of two or more laser light sources are focused, and the copper oxide particles are sintered with the output light of about 10 to 20 W.

<Metal wiring manufacturing equipment>
Next, the metal wiring manufacturing apparatus of this Embodiment is demonstrated. The metal wiring manufacturing apparatus according to the present embodiment includes a plurality of light sources and a focusing control unit that controls each light beam emitted from the plurality of light sources so as to be focused on the processing target layer. FIG. 4 is a schematic diagram showing the entire metal wiring manufacturing apparatus according to the present embodiment. FIG. 5 is a schematic diagram illustrating an example of scanning of a metal wiring and a light beam according to the present embodiment. In some cases, description will be made with reference to FIGS.

(Focusing control unit)
The focusing control unit 60 has been described in the section <Method for manufacturing metal wiring> above, and for details, refer to that. The focusing control unit 60 is preferably the wavelength selection member 61 described with reference to FIG. 2A, the reflective polarizing plate 62 described with reference to FIG. 2B, or the lens 63 described with reference to FIG. 2C.

  As shown in FIG. 1, a mirror 71 or the like is disposed between the wavelength selection member 61 and the laser light source 52, and the laser light 54 emitted from the laser light source 52 is reflected by the mirror 71 to select the wavelength. The light may be incident on the member 61 or may be directly incident on the wavelength selection member 61 from the laser light source 52. As shown in FIGS. 2B and 2C, the same applies to the case where a reflective polarizing plate 62 is used as the focusing control unit 60 or the lens 63 is used.

(Galvano scanner)
As shown in FIG. 4, the laser beam 53 emitted from the laser light source 51 and the laser beam 54 emitted from the laser light source 52 are focused by the focusing control unit 60 described above, and the focused laser beams 53 and 54 are The light is incident on a galvano scanner which is an example of the light beam scanning unit 57. The beam scanning unit 57 includes an X-axis galvano mirror 57a, an X-axis galvano motor 57b, a Y-axis galvano mirror 57c, and a Y-axis galvano motor 57d. Further, an fθ lens and a Z-axis adjusting drive lens (not shown) may be provided.

  Further, the X-axis galvano motor 57 b and the Y-axis galvano motor 57 d of the light beam scanning unit 57 are electrically connected to the scanner control unit 54.

  The scanner control unit 54 includes a processor that executes various processes, a memory, and the like. The memory is composed of one or a plurality of storage media such as a ROM (Read Only Memory) and a RAM (Random Access Memory) depending on the application. The galvano scanner 53 is configured to be able to control the rotation angle and the rotation speed of the X-axis galvano motor 57b and the Y-axis galvano motor 57d in accordance with a control signal from the scanner control unit 34.

  The laser beams 53 and 54 are scanned by the light beam scanning unit 57 and irradiated onto the surface of the layer 11 to be processed, which is formed on the support 56 and contains the copper oxide particles and the dispersant. Further, a lens may be disposed between the light beam scanning unit 57 and the processing target layer 11 so that the laser beams 53 and 54 are condensed on the processing target layer 11.

  In the present embodiment, the light beam scanning unit 57 uses the X-axis and Y-axis galvanometer mirrors 57a and 57c for movement in the X-axis direction and the Y-axis direction, but either one, for example, only in the X-axis direction. The movement in the Y-axis direction may be performed by moving a mounting table (not shown) on which the support 56 is placed along the Y-axis direction with a motor or the like.

  Here, although the galvano scanner has been described as an example of the light beam scanning unit 57, it is not particularly limited. For example, the light beam scanning unit 57 is focused using an XY stage that can move the support 56 provided with the layer 11 to be processed in both the X-axis direction and the Y-axis direction, instead of the galvano scanner. Instead of moving the laser beams 53 and 54, the support 56 may be moved.

  As shown in FIG. 4, the laser beams 53 and 54 focused by the focusing control unit 60 are irradiated to the processing layer 11 while being scanned by the X-axis galvano mirror 57a and the Y-axis galvano mirror 57c of the light beam scanning unit 57. The

  As described above, in the metal wiring manufacturing apparatus 50 of the present embodiment shown in FIG. 4, since the plurality of laser beams 53 and 54 can be focused by the focusing control unit 60, the output is suitable for sintering of the processing target layer 11. The layer 11 to be processed can be irradiated with the laser beams 53 and 54 in a state where the value is increased to the above value. Therefore, the metal particles contained in the layer to be processed 11 can be effectively sintered to form a low resistance metal wiring. Further, by performing the focusing control using the focusing control unit 60, it is possible to focus the light on the layer 11 to be processed appropriately and easily. That is, by using, for example, the wavelength selection member 61 shown in FIG. 2A or the reflective polarizing plate 62 shown in FIG. 2B as the focusing control unit 60, a plurality of lights can be collected on the same optical axis. 11 can be irradiated with appropriately high output light. In addition, for example, by using the lens 63 shown in FIG. 2C as the focusing control unit 60, it is possible to appropriately collect light on the processing target layer 11. By using the lens 63, the number of light sources can be easily increased, and a desired output can be obtained with a simple configuration.

  Further, as shown in FIG. 4, the light focused by the focusing control unit 60 is direction-controlled by the light beam scanning unit 57 and scans the processing target layer 11. In this way, by controlling the direction of the focused light by the light beam scanning unit 57, the processing target layer 11 can be sintered into a desired pattern, and a metal wiring having a desired shape can be formed.

(Metal wiring)
Next, the metal wiring formed by the above-described metal wiring manufacturing method will be described. For example, the focused light is irradiated to the copper oxide ink shown in FIG. Thereby, copper oxide quantum is reduced to copper particles. Thus, the copper particle by which the copper oxide particle was reduced is called reduced copper. At this time, the phosphorus-containing organic substance is modified into a phosphorus oxide. In the phosphor oxide, an organic substance such as the ester salt 13b described above is decomposed by the heat of light and does not exhibit electrical insulation.

  Moreover, when the copper oxide particles 12 are used, the copper oxide changes into copper particles made of reduced copper and sinters by the heat of light, and adjacent copper particles are integrated. As a result, the metal wiring 1 having excellent electrical conductivity shown in FIG. In FIG. 5, the metal wiring 1 is formed by irradiating the processing layer 11 with return light and reciprocating the scanning lines (slightly thick solid line portions). In FIG. 5, there is an interval between adjacent scanning lines, but this is for easy understanding. In practice, the scanning lines are reciprocated while being overlapped. The metal wiring 1 having an area and shape can be formed.

  When the copper oxide ink shown in FIG. 3 is used, the phosphorus element remains in the reduced copper in the metal wiring 1. The phosphorus element exists as at least one of a phosphorus element simple substance, a phosphorus oxide, and a phosphorus-containing organic substance. The remaining phosphorus element is segregated in the metal wiring 1 and there is no fear that the resistance of the metal wiring 1 will increase.

<Configuration of structure with metal wiring>
FIG. 6 is a schematic cross-sectional view showing the structure with metal wiring according to the present embodiment. As shown in FIG. 6, the structure with metal wiring 20 includes a support (substrate) 21, an insulating region 22 containing copper oxide and phosphorus-containing organic matter in a cross-sectional view on the surface formed by the support 21, and A metal wiring 23 formed by sintering copper particles and a single layer 24 arranged adjacent to each other. The insulating region 22 is a region that is not irradiated with light in the layer to be processed 11.

(Support)
The support 21 constitutes a surface on which the single layer 24 is arranged. The shape is not particularly limited.

  The material of the support 21 is preferably an insulating material in order to ensure electrical insulation between the metal wirings 23 separated by the insulating region 22. However, it is not always necessary that the entire support 21 is made of an insulating material. Only the portion constituting the surface on which the single layer 24 is disposed needs to be an insulating material.

  More specifically, the support 21 may be a flat plate, a film, or a sheet. The plate-like body is a support (also called a base material) used for a circuit board such as a printed board. The film or sheet is a base film which is a thin film insulator used for a flexible printed circuit board, for example.

  The support 21 may be a three-dimensional object. A single layer can also be arranged on a curved surface or a surface including a step formed by a three-dimensional object.

  As an example of the three-dimensional object, a casing of an electric device such as a mobile phone terminal, a smart phone, a smart glass, a television, or a personal computer can be given. Other examples of the three-dimensional object include a dashboard, an instrument panel, a handle, and a chassis in the automobile field.

(Single layer)
In the present embodiment, it can be said that the single layer 24 is a mixture of the insulating region 22 and the metal wiring 23.

  “Single” in the single layer 24 means that the layer is not a multilayer structure and that the layers are continuous in cross-sectional view. That the layers are continuous in a cross-sectional view means that it does not include a state in which, for example, a layer between the patterned wiring layers is filled with a solder paste as seen in a printed circuit board. .

  Therefore, the single single layer 24 does not mean that the whole is homogeneous, and the electrical conductivity, the particle state (fired and unsheathed) like the relationship between the insulating region 22 and the metal wiring 23. (Firing) or the like may be different, or a boundary (interface) may exist between the two.

(Insulation area)
The insulating region 22 includes copper oxide and a phosphorus-containing organic material and exhibits electrical insulation. It can be said that the insulating region 22 is an unirradiated region that has not been irradiated with light. The insulating region 22 can also be said to be an unreduced region where copper oxide is not reduced by light irradiation. The insulating region 22 can also be said to be an unfired region that has not been fired by light irradiation.

(Metal wiring)
The metal wiring 23 contains copper and exhibits electrical conductivity. It can be said that the metal wiring 23 is an irradiated region that has been irradiated by a laser. The metal wiring 23 can also be said to be a reduction region including reduced copper in which copper oxide is reduced by light irradiation. The metal wiring 23 can also be said to be a fired region including a fired body obtained by firing the insulating region 22 by light irradiation.

  The shape of the metal wiring 23 in a plan view, that is, the pattern may be any of a linear shape, a curved shape, a circular shape, a square shape, a bent shape, and the like, and is not particularly limited. Since the pattern is formed by scanning with laser light, it is difficult to be restricted by the shape.

  The boundary between the insulating region 22 and the metal wiring 23 is preferably a straight line along the thickness direction (vertical direction shown in FIG. 3) of the single layer 24 in a sectional view, but may have a taper angle. There is no particular limitation. However, it is not essential that the boundary is clear.

  The metal wiring 23 does not need to be completely reduced in a sectional view. For example, it is preferable that there is an unreduced portion near the support 56. Thereby, the adhesiveness between the metal wiring 23 and the support body 21 becomes high.

  Next, with reference to FIG. 7, the manufacturing method of the structure with metal wiring which concerns on this Embodiment is demonstrated more concretely. FIG. 7 is an explanatory view showing each step of the manufacturing method of the structure with metal wiring according to the present embodiment. In FIG. 7A, copper acetate is dissolved in a mixed solvent of water and propylene glycol (PG), and hydrazine is added and stirred.

  Next, in (b) and (c) in FIG. 7, the supernatant and the precipitate were separated by centrifugation. Next, in (d) in FIG. 7, a dispersant (phosphorus-containing organic substance) and alcohol are added to the resulting precipitate and dispersed.

  Next, in (e) and (f) in FIG. 7, concentration and dilution by the UF membrane module are repeated, the solvent is replaced, and a dispersion I containing copper oxide particles is obtained.

In (g) and (h) in FIG. 7, dispersion I was coated on a PET support (described as “PET” in FIG. 7 (h)) by spray coating, and contained copper oxide and phosphorus. A coating layer (processed layer) containing an organic substance (described as “Cu ₂ O” in FIG. 7H) is formed.

  Next, in FIG. 7 (i), the coating layer is irradiated with laser, a part of the coating layer is selectively baked, and the copper oxide is described as copper (in FIG. 7 (i), “Cu”). Reduced). As a result, in FIG. 7 (j), an insulating region containing copper oxide and a phosphorus-containing organic substance (described as “A” in FIG. 7 (j)) and a metal wiring containing copper (FIG. 7) are formed on the support. 7 (j), described as “B”), a structure with metal wiring is obtained in which a single layer is formed adjacent to each other.

  In this embodiment, copper oxide is reduced to form copper, and heat treatment is performed with laser light under conditions where the produced copper is integrated by sintering (fusion) to form metal wiring. To do. This process is called a baking process.

  Next, components of the metal wiring manufacturing method according to the present embodiment will be described in more detail.

<Details of structure with metal wiring>
Hereinafter, each structure of the structure 20 with metal wiring which concerns on this Embodiment is demonstrated concretely. However, each configuration is not limited to the specific examples given below.

(Support)
Specific examples of the support include, for example, a support made of an inorganic material (hereinafter referred to as “inorganic support”) or a support made of resin (hereinafter referred to as “resin support”).

  The inorganic support is made of, for example, glass, silicon, mica, sapphire, crystal, clay film, and ceramic material. The ceramic material is, for example, alumina, silicon nitride, silicon carbide, zirconia, yttria and aluminum nitride, and a mixture of at least two of these. In addition, as the inorganic support, a support made of glass, sapphire, crystal, or the like that has particularly high light transmittance can be used.

  Examples of the resin support include polyimide (PI), polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), polyester, polycarbonate (PC), polyvinyl alcohol (PVA), and polyvinyl butyral ( PVB), polyacetal (POM), polyarylate (PAR), polyamide (PA), polyamideimide (PAI), polyetherimide (PEI), polyphenylene ether (PPE), modified polyphenylene ether (m-PPE), polyphenylene sulfide ( PPS), polyether ketone (PEK), polyphthalamide (PPA), polyether nitrile (PENt), polybenzimidazole (PBI), polycarbodiimide, polysiloxane, Rimethacrylamide, nitrile rubber, acrylic rubber, polyethylene tetrafluoride, epoxy resin, phenol resin, melamine resin, urea resin, polymethyl methacrylate resin (PMMA), polybutene, polypentene, ethylene-propylene copolymer, ethylene-butene -Diene copolymer, polybutadiene, polyisoprene, ethylene-propylene-diene copolymer, butyl rubber, polymethylpentene (PMP), polystyrene (PS), styrene-butadiene copolymer, polyethylene (PE), polyvinyl chloride ( PVC), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK), phenol novolac, benzocyclobutene, polyvinylphenol, polychloropyrene, polyoxymethylene, polysulfo (PSF), polyphenylsulfone resin (PPSU), cycloolefin polymer (COP), acrylonitrile / butadiene / styrene resin (ABS), acrylonitrile / styrene resin (AS), nylon resin (PA6, PA66) polybutyl terephthalate resin A support composed of (PBT) polyethersulfone resin (PESU), polytetrafluoroethylene resin (PTFE), polychlorotrifluoroethylene (PCTFE), silicone resin, and the like can be used.

  Moreover, although not distinguished above, a resin sheet containing cellulose nanofibers can also be used as a support.

  In particular, at least one selected from the group consisting of PI, PET, and PEN is excellent in adhesion with a single layer, has good market distribution and is available at low cost, and is significant from a business perspective, preferable.

  Furthermore, when at least one selected from the group consisting of PP, PA, ABS, PE, PC, POM, PBT, m-PPE, and PPS is a casing, it has excellent adhesion to a single layer and is moldable. It is preferable because it has excellent mechanical strength after molding and has heat resistance enough to withstand laser irradiation when forming metal wiring.

  The deflection temperature under load of the resin support is preferably 400 ° C. or less, more preferably 280 ° C. or less, and further preferably 250 ° C. or less. A support having a deflection temperature under load of 400 ° C. or lower is available at low cost, and is significant and preferable from the viewpoint of business. The deflection temperature under load is, for example, compliant with JIS K7191.

  The thickness of the support can be, for example, 1 μm to 10 mm, preferably 25 μm to 250 μm. It is preferable that the thickness of the support is 250 μm or less because the electronic device to be manufactured can be reduced in weight, space-saving, and flexible.

  In addition, when a support body is a housing | casing, the thickness can be 1 micrometer-10 mm, for example, Preferably, it is 200 micrometers-5 mm. By selecting this range, the present inventors have revealed that the mechanical strength and heat resistance after molding are expressed.

(Single layer)
The single layer is a mixture of an insulating region containing copper oxide particles and a phosphorus-containing organic substance and a metal wiring containing copper.

(Copper oxide particles)
In the present embodiment, the copper oxide includes, for example, cuprous oxide and cupric oxide. Cuprous oxide is particularly preferable because it tends to be sintered at a low temperature. These cuprous oxides and cupric oxides may be used alone or in combination.

  The copper oxide particles have a core / shell structure, and either the core or the shell may be cuprous oxide, or may contain cupric oxide.

  The copper oxide contained in the insulating region has, for example, a fine particle shape. The average particle diameter of the fine particles containing copper oxide is 1 nm to 100 nm, more preferably 1 nm to 50 nm, and still more preferably 1 nm to 20 nm. The smaller the particle diameter, the better the electrical insulation of the insulating region, which is preferable.

  In the single layer, the insulating region may contain copper particles. That is, you may add copper to the below-mentioned dispersion. Phosphorus-containing organic substances are adsorbed on the surface of the copper particles, and electrical insulation can be exhibited.

(Phosphorus-containing organic matter)
The phosphorus-containing organic material is a material that exhibits electrical insulation in the insulating region. It is preferable that the phosphorus-containing organic substance can fix copper oxide to the support. The phosphorus-containing organic substance may be a single molecule or a mixture of a plurality of types of molecules. Further, the phosphorus-containing organic substance may be adsorbed on copper oxide fine particles.

  The number average molecular weight of the phosphorus-containing organic material is not particularly limited, but is preferably 300 to 300,000. If it is 300 or more, it is excellent in electrical insulation.

  It is preferable that the phosphorus-containing organic substance is easily decomposed or evaporated by light or heat. By using an organic substance that is easily decomposed or evaporated by light or heat, a residue of the organic substance is less likely to remain after firing, and a metal wiring having a low resistivity can be obtained.

  The decomposition temperature of the phosphorus-containing organic substance is not limited, but is preferably 600 ° C. or lower, more preferably 400 ° C. or lower, and further preferably 200 ° C. or lower. The boiling point of the phosphorus-containing organic material is not limited, but is preferably 300 ° C. or lower, more preferably 200 ° C. or lower, and further preferably 150 ° C. or lower.

  Although the absorption characteristic of a phosphorus containing organic substance is not limited, It is preferable that the light used for baking can be absorbed. For example, when laser light is used as a light source for firing, it is preferable to use a phosphorus-containing organic substance that absorbs light having an emission wavelength of, for example, 355 nm, 405 nm, 445 nm, 450 nm, 532 nm, or 1064 nm. When the support is a resin, the wavelengths of 355 nm, 405 nm, 445 nm, 450 nm, and 532 nm are particularly preferable.

  The structure is preferably a phosphate ester salt of a high molecular weight copolymer having a group having an affinity for copper oxide. For example, the structure of the chemical formula (1) is preferable because it adsorbs with copper oxide and is excellent in adhesion to a support.

  As an example of the ester salt, the structure of the chemical formula (2) can be given.

  Moreover, the structure of Chemical formula (3) can be mentioned as an example of a phosphorus containing organic substance.

  The organic structure of the phosphorus-containing organic substance includes polyethylene glycol (PEG), polypropylene glycol (PPG), polyimide, polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), polyester, polycarbonate (PC ), Polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyacetal, polyarylate (PAR), polyamide (PA), polyamideimide (PAI), polyetherimide (PEI), polyphenylene ether (PPE), polyphenylene sulfide (PPS) ), Polyether ketone (PEK), polyphthalamide (PPA), polyether nitrile (PENt), polybenzimidazole (PBI), polycarbodi , Polysiloxane, polymethacrylamide, nitrile rubber, acrylic rubber, polyethylene tetrafluoride, epoxy resin, phenol resin, melamine resin, urea resin, polymethyl methacrylate resin (PMMA), polybutene, polypentene, ethylene-propylene copolymer Polymer, ethylene-butene-diene copolymer, polybutadiene, polyisoprene, ethylene-propylene-diene copolymer, butyl rubber, polymethylpentene (PMP), polystyrene (PS), styrene-butadiene copolymer, polyethylene (PE) , Polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polyether ether ketone (PEEK), phenol novolac, benzocyclobutene, polyvinyl phenol, polychloropyrene, polyoxy Methylene, polysulfone (PSF), polysulfide, silicone resins, can be used aldose, cellulose, amylose, pullulan, dextrin, glucan, fructans, the structure of chitin. A structure obtained by modifying a functional group of these structures can be used, a structure obtained by modifying these structures can be used, and a copolymer of these structures can also be used. A phosphorus-containing organic substance having a skeleton selected from a polyethylene glycol structure, a polypropylene glycol structure, a polyacetal structure, a polybutene structure, and a polysulfide structure is preferable because it easily decomposes and does not easily leave a residue in a metal wiring obtained after firing.

  As a specific example of the phosphorus-containing organic substance, a commercially available material can be used. Specifically, DISPERBYK (registered trademark) -102, DISPERBYK-103, DISPERBYK-106, DISPERBYK-109, DISPERBYK-110 manufactured by Big Chemie. DISPERBYK-111, DISPERBYK-118, DISPERBYK-140, DISPERBYK-145, DISPERBYK-168, DISPERBYK-180, DISPERBYK-182, DISPERBYK-187, DISPERBYK-191, DISPERBYK-191, DISPERBYK-191, DISPERBYK-191, DISPERBYK-191 -199, DISPERBYK-2000, DISPERBYK-200 DISPERBYK-2008, DISPERBYK-2009, DISPERBYK-2010, DISPERBYK-2012, DISPERBYK-2013, DISPERBYK-2015, DISPERBYK-2025, DISPERBYK-2050, DISPERBYK-2050, 152 -2061, DISPERBYK-2164, DISPERBYK-2096, DISPERBYK-2200, BYK-405, BYK-607, BYK-9076, BYK-9077, BYK-P105, Prisurf (registered trademark) M208F manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Plysurf DBS etc. can be mentioned. These may be used alone or in combination.

  As the copper oxide contained in the insulating region, a commercially available product may be used, or a synthetic product may be used. As a commercial item, the cuprous oxide microparticles | fine-particles with an average primary particle diameter of 18 nm currently sold from EM Japan are mentioned, for example.

Examples of the method for synthesizing fine particles containing cuprous oxide include the following methods.
(1) Add water and a copper acetylacetonate complex to a polyol solvent, once dissolve the organic copper compound by heating, add further water in an amount necessary for the reaction, and heat to the reduction temperature of the organic copper for reduction. Method.
(2) A method of heating an organic copper compound (copper-N-nitrosophenylhydroxylamine complex) at a high temperature of about 300 ° C. in an inert atmosphere in the presence of a protective agent such as hexadecylamine.
(3) A method of reducing a copper salt dissolved in an aqueous solution with hydrazine.

  The method of (1) is described in, for example, Angelevante Chemi International Edition, No. 40, Volume 2, p. 359, 2001.

  The method of (2) is described, for example, in Journal of American Chemical Society 1999, 121, p. It can be carried out under the conditions described in 11595.

  In the method (3), a divalent copper salt can be suitably used as the copper salt. Examples thereof include copper (II) acetate, copper (II) nitrate, copper (II) carbonate, Examples thereof include copper (II) chloride and copper (II) sulfate. The amount of hydrazine used is preferably 0.2 mol to 2 mol, more preferably 0.25 mol to 1.5 mol, per 1 mol of copper salt.

  A water-soluble organic substance may be added to the aqueous solution in which the copper salt is dissolved. Since the melting point of the aqueous solution is lowered by adding a water-soluble organic substance to the aqueous solution, reduction at a lower temperature becomes possible. As the water-soluble organic substance, for example, alcohol, water-soluble polymer and the like can be used.

  As the alcohol, for example, methanol, ethanol, propanol, butanol, hexanol, octanol, decanol, ethylene glycol, propylene glycol, glycerin and the like can be used. As the water-soluble polymer, for example, polyethylene glycol, polypropylene glycol, polyethylene glycol-polypropylene glycol copolymer and the like can be used.

  The temperature at the time of reduction in the method (3) can be, for example, −20 to 60 ° C., and preferably −10 to 30 ° C. This reduction temperature may be constant during the reaction, or may be raised or lowered during the reaction. In the initial stage of the reaction when the activity of hydrazine is high, the reduction is preferably 10 ° C. or less, and more preferably 0 ° C. or less. The reduction time is preferably 30 minutes to 300 minutes, and more preferably 90 minutes to 200 minutes. The atmosphere during the reduction is preferably an inert atmosphere such as nitrogen or argon.

  Among the methods (1) to (3), the method (3) is preferable because the operation is simple and particles having a small particle diameter are obtained.

(Metal wiring)
For example, copper in the metal wiring may have a structure in which fine particles containing copper are fused to each other. Moreover, there may be no shape of microparticles | fine-particles and it may be in the state which all fuse | melted. Furthermore, a part may be in the form of fine particles, and the majority may be in a fused state.

  In addition to copper, the metal wiring may contain copper oxide (cuprous oxide, cupric oxide, cuprous oxide) or phosphorus-containing organic matter. For example, the surface side portion of the metal wiring may have a structure in which fine particles containing copper are fused to each other, and the support side portion may have a structure containing copper oxide or a phosphorus-containing organic substance. Thereby, since a copper oxide or a phosphorus containing organic substance produces the strong coupling | bonding of copper particles, and also a copper oxide or a phosphorus containing organic substance can improve adhesiveness with a support body, it is preferable.

  The copper content in the metal wiring is preferably 50% by volume or more, more preferably 60% by volume or more, still more preferably 70% by volume or more, and 100% by volume with respect to the unit volume. Also good. It is preferable that the copper content is 50% by volume or more because the electrical conductivity is increased.

<Method for manufacturing structure with metal wiring>
In the method for manufacturing a structure with metal wiring according to the present embodiment, for example, first, a support having a layer to be processed including copper oxide particles is prepared. For example, first, a layer to be treated (copper oxide ink layer) containing copper oxide particles and a phosphorus-containing organic substance is disposed on the surface formed by the support (support). As this method, (a) a method of applying a dispersion (copper oxide ink) containing copper oxide particles and phosphorus-containing organic matter, (b) a method of spraying copper oxide particles and then applying phosphorus-containing organic matter, c) A method in which a phosphorus-containing organic material is applied and then copper oxide particles are dispersed is used. Hereinafter, the method (a) will be described as an example, but the method is not limited thereto.

(Dispersion preparation method)
Next, a method for preparing the dispersion will be described first. First, a copper oxide dispersion (copper oxide ink) in which copper oxide particles are dispersed in a dispersion medium together with a phosphorus-containing organic substance is prepared.

  For example, the copper oxide particles synthesized by the method (3) are soft agglomerates and are not suitable for coating as they are, so they need to be dispersed in a dispersion medium.

  After the synthesis is completed by the method (3), the synthesis solution and the copper oxide particles are separated by a known method such as centrifugation. To the obtained copper oxide particles, a dispersion medium and a phosphorus-containing organic substance are added and stirred by a known method such as a homogenizer to disperse the copper oxide particles in the dispersion medium.

  The phosphorus-containing organic substance according to the present embodiment functions as a dispersant. However, another dispersant may be added as long as it does not affect the electrical insulation of the insulating region.

  Depending on the dispersion medium, the copper oxide particles are difficult to disperse and may not be sufficiently dispersed. In such a case, for example, an easily dispersible alcohol such as butanol is used to disperse the copper oxide, followed by substitution with a desired dispersion medium and concentration to a desired concentration. As an example, there is a method in which concentration by a UF membrane and dilution and concentration by a desired dispersion medium are repeated.

(Application)
A thin film (hereinafter referred to as a layer to be processed) made of the dispersion according to the present embodiment is formed on the surface of the support as described above. More specifically, for example, the dispersion is applied onto a support, and if necessary, the dispersion medium is removed by drying to form a layer to be treated. A method for forming the layer to be treated is not particularly limited, and coating methods such as die coating, spin coating, slit coating, bar coating, knife coating, spray coating, and dip coating can be used. It is desirable to apply the dispersion with a uniform thickness on the support using these methods.

(Baking process)
In the present embodiment, copper oxide particles are reduced to form copper particles, and heat treatment is performed under conditions in which the produced copper particles are integrated by sintering (fusion) to form metal wiring. To do. This process is called a baking process.

  The structure with metal wiring according to the present embodiment is formed in, for example, a wiring material such as an electronic circuit board (printed circuit board, RFID, substitute for a wire harness in an automobile, etc.) or a casing of a portable information device (smartphone or the like). The present invention can be suitably applied to antennas, mesh electrodes (capacitance-type electrode films for touch panels), electromagnetic shielding materials, and heat dissipation materials.

  As described above, according to the metal wiring manufacturing method and the metal wiring manufacturing apparatus according to the present embodiment, since a plurality of light beams can be focused, the metal particles can be used in a state where the output is increased to a value suitable for sintering. Can be irradiated with light. Therefore, the metal particles can be effectively sintered to obtain a low resistance metal wiring.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to these Examples and a comparative example.

Example 1
<Copper oxide dispersion>
In a mixed solvent of 7560 g of distilled water (manufactured by Kyoei Pharmaceutical Co., Ltd.) and 3494 g of 1,2-propylene glycol (manufactured by Kanto Chemical Co., Ltd.), 806 g of copper (II) acetate monohydrate (manufactured by Kanto Chemical Co., Ltd.) is dissolved. The liquid temperature was adjusted to -5 ° C by an external temperature controller. After adding 235 g of hydrazine monohydrate (manufactured by Tokyo Chemical Industry Co., Ltd.) over 20 minutes and stirring for 30 minutes, the liquid temperature was adjusted to 25 ° C. with an external temperature controller and stirred for 90 minutes. After stirring, it was separated into a supernatant and a precipitate by centrifugation. To 390 g of the obtained precipitate, 13.7 g of DISPERBYK-145 (manufactured by Big Chemie) (dispersant content 4 g), 54.6 g of Surflon S611 (manufactured by Seimi Chemical), and 907 g of ethanol (manufactured by Kanto Chemical Co., Inc.) are added. Dispersion was performed using a homogenizer to obtain 1365 g of cuprous oxide dispersion.

<Method for quantifying hydrazine>
The hydrazine was quantified by the standard addition method.

To 50 μL of a sample (copper nanoink), 33 μg of hydrazine, 33 μg of a surrogate substance (hydrazine ¹⁵ N ₂ H ₄ ), and 1 ml of benzaldehyde 1% acetonitrile solution were added. Finally, 20 μL of phosphoric acid was added, and after 4 hours, GC / MS measurement was performed.

Similarly, 66 μg of hydrazine, 33 μg of surrogate substance (hydrazine ¹⁵ N ₂ H ₄ ), and 1 ml of benzaldehyde 1% acetonitrile solution were added to 50 μL of the sample (copper nanoink). Finally, 20 μL of phosphoric acid was added, and after 4 hours, GC / MS measurement was performed.

Similarly, hydrazine 133 μg, surrogate substance (hydrazine ¹⁵ N ₂ H ₄ ) 33 μg, and benzaldehyde 1% acetonitrile solution 1 ml were added to 50 μL of the sample (copper nanoink). Finally, 20 μL of phosphoric acid was added, and after 4 hours, GC / MS measurement was performed.

Finally, to 50 μL of the sample (copper nanoink), without adding hydrazine, 33 μg of surrogate substance (hydrazine ¹⁵ N ₂ H ₄ ) and 1 ml of benzaldehyde 1% acetonitrile solution were added, and finally 20 μL of phosphoric acid was added, and after 4 hours, GC / MS measurement was performed.

  The peak area value of hydrazine was obtained from the chromatogram of m / z = 207 from the above four GC / MS measurements. Next, the surrogate peak area value was obtained from the mass chromatogram of m / z = 209. The calibration curve by the standard addition method was obtained by taking the weight of added hydrazine / weight of added surrogate substance on the x-axis and the peak area value of hydrazine / the peak area value of the surrogate substance on the y-axis.

  The value of the Y-intercept obtained from the calibration curve was divided by the weight of added hydrazine / the weight of added surrogate substance to obtain the weight of hydrazine.

<Particle size measurement>
The average particle diameter of the copper oxide ink was measured by a cumulant method using FPAR-1000 manufactured by Otsuka Electronics.

  The dispersion was well dispersed. The content of cuprous oxide was 20 g, and the particle size was 21 nm. The amount of hydrazine was 3000 ppm.

<Coating film>
The obtained dispersion was applied to a polyimide film (manufactured by Toray DuPont, Kapton 500H, thickness 125 μm) by spin coating, and kept in an oven at 40 ° C. for 2 hours to volatilize the solvent. A membrane was obtained. The obtained sample 1 had a coating thickness of approximately 1000 nm.

<Metal wiring manufacturing equipment>
As a laser light source, two sets of semiconductor lasers having continuous wave oscillation (CW), a central wavelength of 445 nm, and an output of 2.0 W were prepared. A concave lens was prepared in the focusing control unit. Two types of laser beams were incident on one concave lens and adjusted so as to be focused on approximately one laser beam to obtain a combined laser beam. Further, the combined laser beam was incident on a galvano scanner and adjusted so that the surface of the coating film of the sample 1 was in focus. As a result of measuring the output of the combined laser beam, it was 3.6 W.

<Manufacture of metal wiring>
Pattern data combining rectangular regions (main scanning direction, for example, X-axis direction) having different sizes was prepared and input to a metal wiring manufacturing apparatus. The pattern data has a length in the main scanning direction of L1 = 20 mm and L2 = 10 mm, and a length (width) in the direction perpendicular to the main scanning direction is 3 mm. The scanning speed (V1, V2) was calculated as follows so that the scanning period (F) was 15 Hz, and the combined laser beam was scanned while controlling the scanning speed.
Scanning speed V1 = F × L1 = 300 mm / s
Scanning speed V2 = F × L2 = 150 mm / s
Further, when the combined laser beam was reciprocally scanned in the main scanning direction, the movement pitch in the direction perpendicular to the main scanning direction was controlled so that the scanning line had an overlap rate of 96%.

  In the portion irradiated with the combined laser beam, the copper oxide in the coating film was reduced to obtain a conductive pattern made of reduced copper. The conductive pattern had a shape in which rectangular regions having different sizes were combined.

<Resistance measurement>
The obtained conductive pattern was cut in a region of L1 = 20 mm, width 3 mm, L2 = 10 mm, width 3 mm, and the specific resistance value was evaluated by a four-terminal measurement method. As a result, the conductive pattern was independent of the length of the conductive pattern. The resistance was about 50 μΩcm, and the resistance was sufficiently low for use as a metal wiring.

<Observation of overlap part>
The surface of the obtained conductive pattern was observed with an optical microscope. The scanning line of the combined laser beam was confirmed at an interval of 13.2 μm. The width of the locus of the non-overlapping portion of the scanning end portion of the conductive pattern was 320 μm. The overlap ratio calculated by the following formula was 95.9%.
(Overlap ratio) = (320 μm−13.2 μm) ÷ 320 μm

(Example 2)
Using two lasers with continuous wave oscillation (Continuous Wave: CW), a center wavelength of 532 nm, and a laser beam output of 3.0 W as the laser light source, the scanning speed (V) is calculated so that the scanning period (F) is 20 Hz. The combined laser beam was scanned while controlling the scanning speed. As a result of measuring the output of the combined laser beam, it was 5.3 W.

  Other operations were the same as in Example 1 to obtain a conductive pattern. The resistance was measured in the same manner as in Example 1. As a result, the resistance was approximately 70 μΩcm, which was sufficiently low for use as a metal wiring.

(Example 3)
As a laser light source, two sets of semiconductor lasers having continuous wave oscillation (CW), a central wavelength of 445 nm, and an output of 2.0 W were prepared. In the focusing control unit, a wire grid polarizer (manufactured by Asahi Kasei Co., Ltd.) was prepared as a reflective polarizing plate. As shown in FIG. 2B, a laser beam was incident and transmitted through one surface of the wire grid polarizer, and the other laser beam was incident and reflected on the other surface. At this time, the polarization components were adjusted so that each laser beam was orthogonally polarized. Further, a combined laser beam was obtained by adjusting the two laser beams so as to be substantially one laser beam. Further, the combined laser beam was incident on a galvano scanner and adjusted so that the surface of the coating film of the sample 1 was in focus. As a result of measuring the output of the combined laser beam, it was 3.3 W.

  Other operations were the same as in Example 1 to obtain a conductive pattern. The resistance was measured in the same manner as in Example 1. As a result, it was approximately 50 μΩcm, and the resistance was sufficiently low to be used as a metal wiring.

Example 4
As a laser light source, a set of semiconductor laser light sources having continuous wave oscillation (Continuous Wave: CW), a central wavelength of 445 nm and an output of 2.0 W, and a set of laser light sources having a central wavelength of 532 nm and an output of 2.0 W were prepared. In the focusing control unit, a dichroic mirror (Sigma Kogyo Co., Ltd .: SDM515S) was prepared as a wavelength selection member. As shown in FIG. 2A, a laser beam having a wavelength of 532 nm was incident from one surface and transmitted, and a laser beam having a wavelength of 445 nm was incident and reflected on the other surface. At this time, a combined laser beam was obtained by adjusting the two laser beams so as to be substantially one laser beam. Further, the combined laser beam was incident on a galvano scanner and adjusted so that the surface of the coating film of the sample 1 was in focus. As a result of measuring the output of the combined laser beam, it was 3.5 W.

  Other operations were the same as in Example 1 to obtain a conductive pattern. The resistance was measured in the same manner as in Example 1. As a result, it was approximately 50 μΩcm, and the resistance was sufficiently low to be used as a metal wiring.

(Comparative Example 1)
A laser is applied to the surface of the coating film of the sample 1 in the same manner as in Example 1 except that one laser diode set having a central wavelength of 445 nm and an output of 2.0 W is used as a laser light source without focusing a plurality of laser beams. Irradiated with light. Cuprous oxide was not completely reduced, and a conductive pattern could not be obtained.

  As described above, in the embodiment, the laser beam is applied to the coating film containing copper oxide in a state where the output of the laser beam is increased to a value suitable for sintering by focusing a plurality of laser beams using the focusing control unit. I was able to irradiate light. Thereby, the laser beam of a wavelength suitable for sintering copper oxide copper particles could be irradiated to the coating film with an output suitable for sintering, and the copper oxide copper particles could be effectively sintered. As a result, a low resistance conductive pattern could be obtained. In the comparative example, the output of laser light having a wavelength suitable for sintering of copper oxide copper particles could not be increased, and the copper particles could not be sintered.

  In the above embodiment, the copper oxide particles are described as an example of the metal particles. However, the present invention can be applied to the case where the layer to be processed including the metal particles is sintered to form the metal wiring. . Accordingly, the metal particles include at least one selected from the group consisting of copper, silver, gold, and aluminum.

  In addition, the present invention can be applied to the case where a layer to be treated including metal oxide particles other than copper oxide particles (for example, fine particles of iron oxide, magnesium oxide, nickel oxide, etc.) is sintered to form metal wirings and electrodes. Can be applied.

  Moreover, in the said embodiment, the to-be-processed layer containing a metal particle is formed on the support body. However, the support itself may contain metal particles.

  Further, in the above embodiment, the case where the layer to be treated containing metal particles is formed from a dispersion containing metal particles and a phosphorus-containing organic substance as a dispersant has been described as an example. Dispersants other than organic substances may be used.

  Moreover, although each embodiment of the present invention has been described, as another embodiment of the present invention, the above embodiments may be combined in whole or in part.

  The embodiments and examples of the present invention are not limited to the above-described embodiments and examples, and various changes, substitutions, and modifications can be made without departing from the spirit of the technical idea of the present invention. May be. Furthermore, if the technical idea of the present invention can be realized in another way by technological advancement or another derived technique, the method may be used. Accordingly, the claims cover all embodiments that can be included within the scope of the technical idea of the present invention.

  In the present embodiment, the configuration in which the present invention is applied to a metal wiring manufacturing method and a metal wiring manufacturing apparatus has been described. However, the present invention can also be applied to a method and apparatus for irradiating a light beam having a desired wavelength with a desired output. It is.

  As described above, the present invention has an effect that the metal particles can be irradiated with light in a state where the output is increased to a value suitable for sintering, and in particular, in a metal wiring manufacturing method and a metal wiring manufacturing apparatus. Useful. Therefore, it can utilize suitably for manufacture of wiring materials, such as an electronic circuit board, a mesh electrode, an electromagnetic wave shielding material, and a thermal radiation material.

DESCRIPTION OF SYMBOLS 1, 23 Metal wiring 11 Processed layer 12 Copper oxide particle 13 Phosphate ester salt 20 Structure with metal wiring 21, 56 Support body 22 Insulation region 23 Metal wiring 24 Single layer 50 Metal wiring manufacturing apparatus 51, 52 Laser light source 53, 54 Laser light 57 Light beam scanning unit 60 Focus control unit 61 Wavelength selection member 62 Reflective polarizing plate 63 Lens

Claims (13)

  A method of manufacturing a metal wiring, comprising controlling the light beams emitted from a plurality of light sources to be focused on a layer to be treated containing metal particles, and sintering the metal particles.   The method of manufacturing a metal wiring according to claim 1, wherein the light beam is focused on the processing layer using a focusing control unit disposed between the light source and the processing layer. .   3. The method of manufacturing a metal wiring according to claim 1, wherein the metal particles contain at least one selected from the group consisting of copper, silver, gold, and aluminum.   The method for manufacturing a metal wiring according to claim 3, wherein the metal particles are copper oxide particles.   The method for manufacturing a metal wiring according to claim 4, wherein the layer to be treated is formed using a dispersion containing the copper oxide particles and a dispersant.   A metal wiring manufacturing apparatus, comprising: a plurality of light sources; and a focusing control unit that controls the respective light beams emitted from the plurality of light sources so as to focus the metal particles on the processing target layer.   7. The metal according to claim 1, wherein the focusing control unit transmits at least one of the light beams, reflects the remaining light beams, and focuses the light on the layer to be processed. Wiring manufacturing method or metal wiring manufacturing apparatus.   The metal wiring manufacturing method or the metal wiring manufacturing apparatus according to claim 7, wherein the focusing control unit is a wavelength selection member.   8. The metal wiring manufacturing method or metal wiring manufacturing apparatus according to claim 7, wherein the focusing control unit is a reflective polarizing plate.   2. The focusing control unit having an incident surface and an exit surface, wherein a plurality of the light beams are incident on the entrance surface, emitted from the exit surface, and focused on the processing target layer. The metal wiring manufacturing method or metal wiring manufacturing apparatus according to claim 6.   11. The metal wiring manufacturing method or metal wiring manufacturing apparatus according to claim 10, wherein the focusing control unit is a lens.   12. The metal wiring manufacturing method or metal wiring manufacturing apparatus according to claim 1, wherein the light beam is a laser beam having a central wavelength of 355 nm or more and 550 nm or less.   13. The metal wiring manufacturing method or metal wiring manufacturing apparatus according to claim 12, wherein the central wavelength is 400 nm or more and 532 nm or less.

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