JP5312368B2 - Metal composite substrate and manufacturing method thereof - Google Patents

Abstract

The invention discloses a metal composite substrate, which avoids the disadvantage of selective dissolution from a head face to the common cladding material through an all-sided aluminium coated layer, and solves the problem that aluminium composition cannot be managed strictly in the event of forming an aluminium layer of a surface layer by fusing, plating and the like. The metal composite substrate has excellent insulating property and high-temperature intensity. Aluminium or aluminium alloy is coated on the whole surface of a core material formed by metal whose heat resisting strength above 300 DEG C is higher than that of aluminium. An aluminium plate or an aluminium alloy plate is stuck on at least one surface of the obtained aluminium or aluminium alloy layers. At least one surface of the aluminium plate or the aluminium alloy plate has an anode oxidization coated film.

Description

  The present invention relates to a metal composite plate. The metal composite substrate of the present invention relates to a metal composite substrate having at least one surface covered with aluminum or an aluminum alloy having an anodized film and having excellent strength characteristics at high temperatures.

Semiconductor substrates are required to have insulating properties and heat dissipation. High flexibility is also preferable. When an aluminum alloy is used for a semiconductor substrate, since the aluminum alloy is a highly conductive material, the insulation cannot be satisfied as it is, but by providing an anodized film on the surface, the insulation is dramatically improved. To improve. Moreover, since aluminum alloy is a material with high thermal conductivity, heat dissipation is excellent, and if the plate thickness is selected, flexibility is also excellent. Moreover, when manufacturing as a semiconductor substrate, processing at a high temperature may be performed, in which case heat resistance is required.
For example, a resin material having a relatively high heat resistance such as polyimide is excellent in insulation, so that it may be used as a support for a semiconductor, but cannot withstand an excessively high temperature. In this respect, the aluminum alloy substrate is excellent because it can withstand a certain high temperature.
As examples of semiconductors that require insulating properties and heat resistance, thin film solar cells, light emitting diodes (hereinafter referred to as LEDs), and the like are known.

For example, the following types of thin film solar cells requiring heat resistance are known. Solar cells are roughly classified into three types: (1) single-crystal Si solar cells, (2) polycrystalline Si solar cells, and (3) thin-film solar cells. In contrast to single-crystal Si solar cells and polycrystalline Si solar cells that use Si wafers as substrates, thin-film solar cells use a variety of substrates such as glass substrates, metal substrates, and resin substrates, and light absorption of thin films on these substrates A layer is formed.
As the light absorbing layer, a Si-based thin film of amorphous Si or nanocrystalline Si, a compound-based thin film such as CdS / CdTe, CIS (Cu-In-Se), CIGS (Cu-In-Ga-Se), or the like is used. Further, by using a flexible substrate, it is possible to continuously produce flexible solar cells by a roll-to-roll method in which an insulating layer or a thin film is formed while winding the substrate on a roll.
Conventionally, glass substrates have been mainly used as thin film solar cell substrates. This is excellent in insulation and heat resistance, but the glass substrate is fragile and requires sufficient care for handling, and has a drawback of lacking flexibility. Recently, solar cells have attracted attention as a power supply source for buildings such as houses, and in order to secure sufficient power supply, it is desired to increase the size, area, and weight of solar cells. Therefore, as a substrate material that is hard to break and flexible and can be reduced in weight, a resin substrate, an aluminum alloy substrate, a substrate such as Fe that is clad with aluminum, and the like have been proposed.
And the method of providing an insulating layer, such as an anodic oxide film, on the aluminum alloy substrate and providing a thin-film solar cell layer thereon is known.
In order to form the compound-based thin film as the light absorption layer, a compound is placed on a substrate and sintered at 350 to 650 ° C. depending on the type of the compound. For example, in order to form a CIGS layer in continuous production, it is preferable to sinter at a line speed of 350 to 600 ° C. and 4 to 20 m / min, and a substrate material that can withstand this temperature is desirable.
Further, when performing wiring by soldering or the like, a high temperature may be temporarily applied by soldering, and it is necessary that there be no problem at this time.

  Patent Document 1 proposes a solar cell electrode wire that is less prone to cracking in the solar cell semiconductor substrate when soldering from a wire for wiring rather than from the substrate side, and that is excellent in conductivity.

As another example, a substrate used for an LED is required to have insulating properties and light reflectivity, as well as heat dissipation necessary for light emission and heat resistance that can withstand heating during the manufacturing process.
For example, FIG. 7 is a schematic diagram showing a configuration example of a phosphor-mixed white LED light-emitting element described in Patent Documents 2 and 3, and is also used as part of the structure in the light-emitting element of the present invention. It may be. In FIG. 7, reference numeral 100 denotes a white LED light emitting element. A blue LED 110 is face-down bonded to a substrate 140 having external connection electrodes 120 and 130, and YAG fluorescent particles 150 are mixed into the blue LED 110. Molded with a transparent resin 160. White light is emitted from the white LED light emitting element 100 in the direction of the arrow on the light emitting surface side by the light excited by the YAG fluorescent particles 150 and the afterglow of the blue LED 110.
The energy conversion efficiency of the LED is still low, and it is said that 70 to 80% other than the energy that becomes visible light directly generates heat in the LED element portion, and the substrate to which the LED is attached is required to have heat dissipation.
Further, when mounting wiring or the like, a high temperature may be temporarily applied due to soldering or the like, and the same problem as described above may occur.
Further, in order to obtain excellent light emission characteristics, a function as a light reflecting substrate is required. For the purpose of improving the light emission output, for example, as disclosed in Patent Document 4 and the like, a method is known in which an aluminum substrate is used as a light reflecting substrate to suppress light emission loss and improve the light emission output. However, in order to improve the reflectance over the entire visible light region, whitening of the reflective substrate itself is desired. However, when white resin is used for whitening and imparting insulation, heat generation causes whiteness. There was a problem that the resin deteriorated.

What is common to these is insulation as a substrate for semiconductors and heat resistance during use or during the manufacturing process.
On the other hand, when an aluminum substrate whose anodized film is known to function as an insulating layer is used, there is a problem that the strength at high temperature is insufficient and it is difficult to maintain the shape.
On the other hand, as an aluminum alloy having high high-temperature strength, an alloy to which Fe or Mn is added is known. As an improvement measure, Patent Document 5 describes Si: 0.25 to 0.35 mass%, Fe: 0.00. 05-0.3 mass%, Cu: 0.3-0.5 mass%, Mn: 1.2-1.8 mass%, Sc: 0.05-0.4 mass%, Zr: 0.05- An aluminum alloy containing 0.2% by mass, the balance being Al and impurities, and V: 0.05 to 0.2% by mass, of which Sc concentration is 0.07 to 0.15% by mass, Zr An aluminum alloy having a concentration of 0.07 to 0.1% by mass and a V concentration of 0.07 to 0.1% by mass has been proposed.

  Patent Document 6 proposes a method for specifying the micropore shape of an anodized film as a method for increasing the mechanical strength of an anodized film layer provided on a flexible substrate for solar cells using an aluminum alloy. The content is an insulating material made of an aluminum alloy in which an anodized film having pores is formed on the surface of an aluminum substrate, and the thickness of the anodized film is 0.5 μm or more, and It has a plurality of holes extending in a direction substantially perpendicular to the axis of the pore.

  In paragraph 15 of Patent Document 6, an oxalic acid bath or a sulfuric acid bath can be applied as the anodizing bath, but the internal structure of the anodized film differs depending on the alloy and processing conditions, and as a result, various withstand voltages are obtained. Is obtained. Further, it is described that a higher withstand voltage can be realized by forming a structure in which pores and / or vacancies are filled with Si oxide after anodizing.

Patent Document 7 relates to a metal material with a film suitable for the production of a flexible solar cell, and has a film including an insulating layer to which one kind of alkali metal or a mixture of plural kinds of alkali metals is added, and has a temperature range of 0. The thermal expansion coefficient at ˜600 ° C. is 12 × 10 ⁻⁶ K ⁻¹ , the insulating layer includes at least one oxide layer, and the oxide layer includes Al ₂ O ₃ , TiO ₂ , HfO ₂ , Ta _2. With a coating characterized in that it consists essentially of O ₅ , Nb ₂ O ₅ , a dielectric oxide of any one of these oxide mixtures, preferably Al ₂ O ₃ and / or TiO ₂ Steel products are listed. Also described is a method for producing the steel product with the metal oxide coating by a roll-to-roll process.
Further, Patent Document 8 discloses a substrate for electronic materials composed of a base and a surface insulating layer, and the surface insulating layer is for an electronic material excellent in insulating properties composed of one or more metal oxides and other non-conductive substances. A substrate is described. Further, it is described that an anodic oxide film metal oxide provided on the surface of an aluminum substrate is used as the metal oxide.
Patent Document 9 describes that an insulating layer having a thickness of 0.5 μm or more and a center line average roughness Ra = 0.5-200 μm is provided on the surface of a metal plate including an aluminum alloy plate. Further, it is described that an anodized film is provided on an aluminum substrate and used for an insulating layer.
Patent Document 10 describes an amorphous solar cell substrate using an aluminum substrate having an anodized film provided with an uneven surface.
Patent Document 11 describes a solar cell substrate having an anodized film having fine holes.

WO2005 / 114751 JP Japanese Patent No. 2998696 Japanese Patent Laid-Open No. 11-87784 Japanese Patent Laid-Open No. 2006-100773 No. 2008-81794 JP 2000-349320 A Special table 2007-502536 gazette Japanese Patent Laid-Open No. 11-229187 JP 2000-49372 A JP-A-11-97724 JP 2000-286432 A

Conventionally, a glass substrate has been often used for a substrate of a device that requires high-temperature processing in a manufacturing process, such as a thin film solar cell, among semiconductor supports. However, since the glass substrate does not have flexibility, it is difficult to arrange the glass substrate in a curved shape, and a method of providing a metal substrate as in Patent Documents 7, 8, 9, 10, and 11 has been proposed. However, as described in Patent Documents 8, 9, 10, and 11, using aluminum with an insulating anodic oxide coating on the surface is insufficient in strength at high temperatures, making shape retention difficult. For this reason, when a thin-film solar cell that needs to be provided with a light absorption layer at a high temperature is used, handling at a high temperature is difficult and it is difficult to manufacture stably.
Moreover, although the method of providing an insulating layer in steel products as shown in Patent Document 7 was also proposed, its insulation performance was insufficient, and it was not possible to increase the generated voltage by joining solar cells in series on the substrate. .
On the other hand, a high-strength aluminum alloy as shown in Patent Document 5 has also been proposed, but it is difficult to provide a light absorption layer at a high temperature of 500 ° C. or higher, and in particular, there is a problem that flatness cannot be maintained. Furthermore, Fe or Mn added to aluminum metal tends to form an intermetallic compound with aluminum, and as a result, these intermetallic compounds become defects in the anodized film formed on the surface of the aluminum metal and have insulation resistance. There was a fatal problem of lowering, which was not preferable.

On the other hand, the inventors of the present invention are suitable as a semiconductor substrate material that requires insulation and high-temperature strength, excellent in high-temperature strength, particularly as a material that maintains good flatness and resists handling at high temperatures. We proposed to provide a metal composite substrate that was anodized on a composite material with aluminum on the entire surface.
However, this method has a problem that it is difficult to strictly control the composition of the aluminum material provided on the entire surface by the hot dipping method.

The inventors of the present invention are suitable as a semiconductor material such as a thin film solar cell substrate, excellent in high-temperature strength, particularly as a material that maintains good flatness at high temperatures and withstands handling. By sticking an aluminum plate or an aluminum alloy plate to the surface of the coated core material provided with an aluminum coating layer on the entire surface, the aluminum plate composition of the surface layer can be strictly controlled, and the anode can be controlled on the aluminum plate that can control the composition. It was found that a substrate having excellent insulation and high-temperature strength can be provided by oxidation treatment. As a result, in ordinary clad materials, defects that tend to cause selective dissolution from the end face are prevented by the entire aluminum coating layer, and strict control of the aluminum composition that occurs when the surface aluminum layer is formed by hot dipping etc. Solve the problem of not being able to. The present invention was completed by discovering that an insulating substrate for a semiconductor excellent in insulation performance, high temperature strength resistance, high temperature handling properties, and flatness after high temperature heat treatment can be obtained. Thereby, the board | substrate excellent in high temperature intensity | strength and insulation suitable for semiconductor substrates, such as a solar cell and LED, is provided.
An object of the present invention is to provide a metal composite substrate having an anodized film excellent in high-temperature strength and withstand voltage characteristics as a surface layer, and a method for producing the same.

The present invention has the following configuration.
(1) A coating layer made of aluminum or an aluminum alloy is provided on the entire surface of a core material made of a metal having a heat resistance strength higher than aluminum at 300 ° C. or higher, and an aluminum plate or an aluminum alloy plate is formed on at least one surface of the coating layer A metal composite substrate having an anodized film on at least one surface of an aluminum plate or an aluminum alloy plate of the metal composite substrate.
(2) Preferably, the core material is steel, the anodized film is provided on the entire surface of the metal composite substrate, and the anodized film is a porous anodized film having a thickness of 1 to 200 μm. .

(3) The insulating composite light reflecting substrate in which the anodized film of the metal composite substrate according to any one of the above has a light reflecting surface, and the total reflectance of light having a wavelength of more than 320 nm to 700 nm is 50%. An insulating light reflecting substrate, which has the above, and has a total reflectance of light having a wavelength of 300 nm to 320 nm of 60% or more.
(4) It is preferable that the said light reflection surface has an unevenness | corrugation with an average wavelength of 0.01-100 micrometers.
(5) A white light emitting diode device having a blue light emitting element on an upper layer of a light reflecting surface of the light reflecting substrate, and a fluorescent light emitting body around and / or above the light emitting element.
(6) A thin-film solar cell in which a light absorption layer and an electrode layer are formed on the metal composite substrate.
(7) A thin film system in which a light absorption layer is formed on the metal composite substrate through a back electrode layer, and the light absorption layer includes any one compound of CdS / CdTe, CIS, and CIGS Solar cells are preferred.
(8) A core material made of a metal having a higher heat resistance at 300 ° C. or higher than aluminum is coated on the entire surface with aluminum or an aluminum alloy, and at least one surface of the resulting aluminum or aluminum alloy layer is coated with an aluminum plate or A method for producing a metal composite substrate, in which an aluminum alloy plate is bonded, and at least one surface of the obtained aluminum plate or aluminum alloy plate is subjected to anodizing treatment, water washing treatment, and drying treatment.

The metal composite substrate of the present invention has an anodic oxide film that is excellent in flatness during high-temperature heat treatment and has no film defects on the surface. Because it withstands various processes such as vapor deposition at high temperatures, it can efficiently produce various semiconductor devices in batch or roll-to-roll systems as insulating substrates for solar cell substrates and LED holding substrates. Can do.
In the metal composite substrate of the present invention, the entire surface of the core material is coated with aluminum or an aluminum alloy, and an aluminum or aluminum alloy plate is attached to the upper layer, so that at least one surface of the aluminum plate whose composition is controlled Can be made into an anodized film by anodizing treatment, and an excellent insulating property can be obtained and a withstand voltage characteristic is high. In addition, if an anodic oxide film is provided on the entire surface, it is possible to form an end surface that is insulative, high-temperature strength, and high in mechanical strength as compared with a substrate having an anodic oxide film on a part of the surface. Insulation properties are also excellent, scratch resistance is high, and surface treatment properties are excellent without causing dissolution from the edges during anodizing treatment in an acidic solution.

FIG. 1 is a cross-sectional view showing an example of a metal composite substrate of the present invention. FIG. 2 is a cross-sectional view showing a metal composite substrate according to another aspect of the present invention. FIG. 3 is a cross-sectional view showing an example of the insulating light reflecting substrate of the present invention. FIG. 4 is a cross-sectional view showing an insulating light reflecting substrate according to another aspect of the present invention. FIG. 5 is a schematic view of an anodizing apparatus used for anodizing in the production of the substrate of the present invention. FIG. 6 is a cross-sectional view showing an example of a general configuration of a thin-film solar cell using the metal composite substrate of the present invention. It is the schematic which shows one structural example of the fluorescent substance color mixture type white light emitting diode unit.

<Metal composite substrate>
Preferred examples of the metal composite substrate of the present invention are shown in cross-sectional views in FIGS. In the following description, each of aluminum, aluminum alloy, and aluminum may mean aluminum or an aluminum alloy.
A metal composite substrate 10 shown in FIG. 1 is an aluminum alloy plate layer in which the entire surface of a core material 1 is coated with an aluminum alloy to form an aluminum alloy coating layer 3, and an aluminum alloy plate 5 is bonded to at least one surface thereof. An anodized film 7 is provided on at least one surface.
FIG. 2 shows a metal composite substrate 20 according to another embodiment of the present invention, in which an aluminum alloy plate 5 is bonded in the same manner as in FIG. 1, and an anodized film 7 is provided on all aluminum alloy surfaces including the laminated aluminum alloy plate layer. An embodiment is shown.

[1. Core material]
The core material used in the present invention is a metal material having higher heat resistance at 300 ° C. or higher than that of an aluminum alloy. Specifically, the tensile strength at 300 ° C. or higher can be used as an index for the heat resistance strength. For example, steel, titanium, nickel or the like can be selected, but steel is desirable because it is practical and inexpensive, and it is desirable to be flexible, and soft steel, heat-resistant steel, and stainless steel are used. From the viewpoint of heat resistance, heat resistant steel and stainless steel are more preferable among the steels.
Mild steel is low carbon steel, SS400 etc. can be used.
The heat-resisting steel contains several percent of chromium, nickel, cobalt, tungsten, etc., and is classified into austenitic, ferritic, and martensitic. As the steel used for the plate material, austenitic and ferritic heat resistant steels are desirable, and for austenitic heat resistant steels, SUH309, SUH310, SUH330, SUH660, SUH661 and the like are preferable. For ferritic heat-resistant steel, SUH21, SUH409, SUH446, etc. are preferable.

  Stainless steel is 11% or more chromium, or steel containing 11% or more chromium and also containing Ni. Stainless steel materials are classified into austenitic, ferritic and martensitic. As austenitic stainless steel, SUS304, SUS316, SUS310, SUS309, SUS317, SUS321, SUS347 and the like can be used. As the ferritic stainless steel, SUS430, SUS405, SUS410, SUS436, SUS444, or the like can be used. As martensitic stainless steel, SUS403, SUS440, SUS420, SUS410, or the like can be used. Among these, when using as a flexible board, an austenite type or a ferrite type is preferable. In particular, when it is desired to increase the heat resistance strength, it is preferable to use an austenite system. SUS304 and 316 are common, but SUS310 and SUS309 are preferably used when particularly higher heat resistance is required. Since the thickness of the plate affects the flexibility, it is preferable to reduce the thickness within a range that does not cause an excessive lack of rigidity. From the viewpoint of flexibility, the thickness is 0.5 mm or less, preferably 0.3 mm or less, more preferably 0.1 mm or less. It is preferable to reduce the plate thickness from the viewpoint of raw material costs. However, in order to ensure the minimum rigidity during handling, the lower limit is preferably 0.03 mm or more.

[2. Aluminum or aluminum alloy]
The aluminum or aluminum alloy used for the core material coating layer and the aluminum alloy plate layer of the present invention preferably contains no unnecessary intermetallic compound. Specifically, aluminum having a purity of 99% by mass or more with less impurities is desirable. For example, 99.99 mass% Al, 99.96 mass% Al, 99.9 mass% Al, 99.85 mass% Al, 99.7 mass% AL, 99.5 mass% Al, etc. are desirable. Alternatively, an element that is difficult to form an intermetallic compound can be added. For example, an aluminum alloy in which 2.0 to 7.0% by mass of magnesium is added to 99.9% by mass of Al can be used. Other than magnesium, an additive element having a high solid solution limit such as Cu and Si can be selected. When applied to an insulating semiconductor substrate, the purity of Al can be increased, an intermetallic compound caused by precipitates can be avoided, and the soundness of the insulating layer can be increased. This is because when anodization of an aluminum alloy is performed, the possibility of an insulation failure increases due to an intermetallic compound as a starting point. When applied to a lithographic printing plate support, an element capable of controlling electrochemical surface roughening can be added to aluminum in the surface layer. For example, Cu and Si are typical examples.

[3. Core material coating layer]
A material having a high temperature strength is used for the core material, and an aluminum or aluminum alloy layer is coated as the coating layer. Examples of the coating method include vapor deposition, hot dipping, or electroplating. In the present invention, electroplating and hot dipping methods that can easily protect the end faces are preferred methods.
The thickness of the coating layer is preferably at least 10 μm. The thickness is preferably 20 μm or more, more preferably 30 μm or more. The upper limit of the thickness is restricted by the process when formed by hot dipping, but is preferably 100 μm or less, and more preferably 50 μm or less.
Regarding the hot dipping method, the method described in JP-A-8-144037 can be used.

As a composite material of the aluminum hot dipping method, Alster steel plate, Alster stainless steel of Nisshin Steel Co., Ltd., and Al Sheet of Nippon Steel Corp. are known, and these can also be used.
The aluminum layer to be coated is difficult to control a trace component in the composition, and if this is used as a surface layer, it is difficult to make the aluminum composition of the surface layer to be anodized a desired composition.

[4. Aluminum alloy plate]
Therefore, the coated core material in which the core material is coated with aluminum has an aluminum plate attached to at least one surface thereof. The attaching method is preferably performed by clad rolling. Although the thickness of an aluminum alloy plate is not limited, 1 micrometer-5 mm are preferable.
Thereby, while it is difficult to control the composition of the aluminum layer provided by hot dipping, it is possible to provide an aluminum alloy plate whose composition has been controlled in advance on the surface layer.
Examples of the clad rolling method include the method described in JP-A No. 2001-18074.
One example of the clad rolling method is to adjust the rolling temperature of the aluminum alloy sheet to a range of 300 to 500 ° C., the rolling temperature of the aluminum alloy coated core material to a range of 250 to 450 ° C., and set the rolling reduction to an appropriate range. A core material having an aluminum alloy coating layer on the entire surface and an aluminum alloy plate are bonded together.

[5. Composite metal body]
The resulting composite metal body has a thickness of 20 to 5000 μm and a plate width of 100 to 2000 mm.
The surface roughness of the aluminum alloy plate layer is selected according to the application. In the case of a substrate for a solar cell, it is preferable to have a mirror finish, and in the case of an LED substrate, it is preferable to have a surface roughness corresponding to the required reflectance. The surface roughness Ra is preferably 0.1 nm to 2 μm, and particularly preferably 1 nm to 0.5 μm.
The composite metal body needs to have a tensile strength of 5 MPa or more, preferably 10 MPa or more, while being heat-treated at 500 ° C. or more.
Further, in order to prevent creep during heat treatment at 500 ° C. or higher, it is preferable that the strength causing plastic deformation of 0.1% at the maximum when held at 500 ° C. for 10 minutes is 0.2 MPa or higher. Desirably 0.4 MPa or more, more desirably 1 MPa or more.
If necessary, this composite metal body is further roughened and anodized on the surface of the aluminum, is excellent in surface hardness and adhesion to the image recording layer, and the strength of the support is reduced even after high-temperature burning treatment. It is also useful as a support for a lithographic printing plate that does not cause a decrease in flatness.

[6. Surface treatment method (formation of anodized film)]
The surface aluminum alloy plate layer is preferably subjected to a cleaning treatment for removing dirt or the like using an acid or an organic solvent, if necessary.
Thereafter, anodization is performed in an acidic solution such as sulfuric acid, phosphoric acid, or oxalic acid. The thickness of the anodized film is preferably 5 μm or more, and more preferably 10 μm or more. However, an excessively thick anodic oxide film is not preferable because it takes cost and time to generate the film. Actually, the maximum is 50 μm or less, preferably 30 μm or less.
The electrolyte used for the anodizing treatment is preferably sulfuric acid or an oxalic acid aqueous solution. An oxalic acid film is excellent in the soundness of the obtained anodic oxide film. On the other hand, sulfuric acid is excellent in continuous processing productivity.

Preferred anodizing conditions are shown below.
The current used for the anodic oxidation treatment can be alternating current, direct current, or AC / DC superimposed current. The method of applying the current may be constant or gradually increasing from the initial stage of electrolysis, but the method using direct current is particularly preferable. .
The anodizing treatment may be performed simultaneously on the front and back and the two sides of the composite plate, may be performed simultaneously on the front and back, and then on the two sides, or may be performed sequentially one by one.
As the electrolytic solution flow rate on the aluminum surface, the method of giving the flow rate, the electrolytic cell, the electrode, and the electrolytic solution concentration control method, a known anodizing method can be used.
For example, JP-A-2002-362055, JP-A-2003-001960, JP-A-6-207299, JP-A-6-235089, JP-A-6-280091, JP-A-7-278888, Examples of JP-A-10-109480, JP-A-11-106998, JP-A 2000-17499, JP-A 2001-11698, and JP-A 2005-60781 are examples. As the counter electrode of the composite material plate, aluminum, carbon, titanium, niobium, zirconium, stainless steel, or the like can be used as a counter electrode (cathode) when aluminum is used as an anode. As a counter electrode (anode) when aluminum is used as a cathode, it is possible to use lead, platinum, iridium oxide, or the like.

FIG. 5 shows an example of an apparatus that can be used for the anodizing treatment of the present invention. The apparatus conveys the composite metal body 2 in which an aluminum alloy plate is attached to at least one surface of the coated core material through a plurality of pass rolls 20 and applies a direct current in a predetermined electrolytic solution 22 to the surface thereof. An anodized film is provided. In FIG. 5, the composite metal body 2 conveyed from the left in the drawing rolls into contact with the pass roll 20 and enters the power supply tank 24, where it is energized from the anode 28 through the electrolytic solution 22. The composite metal body 2 is then transported to the oxide layer 25 to become positive (anode), transported against the cathode 30 and subjected to anodization. In order to provide a thick anodic oxide film, the treatment length of the oxide layer 25 can be made longer than the treatment length of the power supply tank 24.
FIG. 5 shows an example in which the electrode is disposed on the lower surface of the surface of the composite metal body to be anodized, but the anodic oxide film is formed on the entire surface of the composite metal body 2 as shown in FIGS. In the case of providing the electrode, it is possible to make the electrode shape into a form capable of anodizing on both sides. By arranging the electrodes so that both sides can be anodized, the lines of electric force also wrap around the end face of the plate, and anodization is performed.
(a) Anodizing treatment in sulfuric acid aqueous solution 100 to 300 g / L of sulfuric acid, more preferably 120 to 200 g / L (including 0 to 10 g / L of aluminum ions), liquid temperature of 10 to 55 ° C. (particularly preferably 20 to 50 ° C.), current density of 10 to 100 A / dm ² (particularly preferably 20 to 80 A / dm ² ), electrolytic treatment time of 5 to 300 seconds (particularly preferably 5 to 120 seconds), and anodization using the composite material plate as an anode Process. The voltage between the composite material plate and the counter electrode at this time is preferably 10 to 150 V, and the voltage is the electrolytic bath composition, the liquid temperature, the flow velocity of the aluminum interface, the power waveform, the distance between the composite material plate and the counter electrode, It varies depending on the electrolysis time.
Aluminum ions are dissolved electrochemically or chemically in the electrolytic solution, but it is particularly preferable to add aluminum sulfate in advance. Further, trace elements contained in the aluminum alloy may be dissolved.

(b) Anodizing treatment in oxalic acid aqueous solution It is preferable that 10 to 150 g / L of oxalic acid (particularly preferably 30 to 100 g / L) and 0 to 10 g / L of aluminum ions are contained. Liquid temperature 10 to 55 ° C. (particularly preferably 10 to 30 ° C.), current density 0.1 to 50 A / dm ² (particularly preferably 0.5 to 10 A / dm ² ), electrolytic treatment time 1 to 100 minutes (particularly preferred 30 to 80 minutes), and anodizing is performed using the composite plate as an anode. The voltage between the composite material plate and the counter electrode at this time is preferably 10 to 150 V, and the voltage is the electrolytic bath composition, the liquid temperature, the flow velocity of the aluminum interface, the power waveform, the distance between the composite material plate and the counter electrode, It varies depending on the electrolysis time.
Aluminum ions are dissolved electrochemically or chemically in the electrolytic solution, but aluminum oxalate may be added in advance. Further, trace elements contained in the aluminum alloy may be dissolved.

[Boric acid electrolysis treatment (sealing treatment)]
The anodized aluminum alloy plate is preferably sealed in a boric acid solution, particularly when it is desired to increase the insulation.
As the sealing treatment, an electrochemical method and a chemical method are known, but an electrochemical method (anodic treatment) in which aluminum of the composite substrate is used as an anode is particularly preferable.
The electrochemical method is preferably a method in which aluminum or an alloy thereof is used as an anode and a direct current is applied to perform sealing treatment. The electrolytic solution is preferably an aqueous boric acid solution, and is preferably an aqueous solution obtained by adding a borate containing sodium to an aqueous boric acid solution. Examples of borates include disodium octaborate, sodium tetraphenylborate, sodium tetrafluoroborate, sodium peroxoborate, sodium tetraborate, and sodium metaborate. These borates are available as anhydrous or hydrated.

As the electrolytic solution used for the sealing treatment, it is particularly preferable to use an aqueous solution obtained by adding 0.01 to 0.5 mol / L sodium tetraborate to a 0.1 to 2 mol / L boric acid aqueous solution. It is preferable that 0 to 0.1 mol / L of aluminum ion is dissolved. Aluminum ions are chemically or electrochemically dissolved in the electrolytic solution by a sealing treatment, and a method of electrolyzing by adding aluminum borate in advance is particularly preferable. Further, trace elements contained in the aluminum alloy may be dissolved.
Preferred sealing treatment conditions are a liquid temperature of 10 to 55 ° C. (particularly preferably 10 to 30 ° C.), a current density of 0.01 to 5 A / dm ² (particularly preferably 0.1 to 3 A / dm ² ), and an electrolytic treatment time. 0.1 to 10 minutes (particularly preferably 1 to 5 minutes).
As the current, an alternating current, a direct current, or an AC / DC superimposed current can be used. The method of applying the current may be constant or gradually increasing from the initial stage of electrolysis, but a method using direct current is particularly preferable. Either a constant voltage method or a constant current method may be used for applying the current.
At this time, the voltage between the composite substrate and the counter electrode is preferably 100 to 1000 V, and the voltage is the electrolytic bath composition, the liquid temperature, the flow velocity at the aluminum interface, the power waveform, the distance between the composite material plate and the counter electrode, the electrolysis It changes with time.
The sealing treatment may be performed simultaneously on the front and back of the composite substrate, or may be sequentially performed on each side.
As the electrolytic solution flow rate on the aluminum surface, the method of giving the flow rate, the electrolytic cell, the electrode, and the concentration control method of the electrolytic solution, the known anodizing method and the sealing method described in the anodizing treatment can be used. It is. The film thickness when anodizing in a boric acid aqueous solution containing sodium borate is desirably 100 nm or more, and more desirably 300 nm or more. The upper limit is the film thickness of the porous anodic oxide film, but 1 μm or less is a practical upper limit from the viewpoint of production cost.
Thereby, a metal composite substrate for a semiconductor substrate, particularly a metal composite substrate for a thin film solar cell substrate that requires high-temperature strength and has a merit of flexibility can be provided.
In addition, a chemically preferable method may be a structure in which pores and / or vacancies are filled with Si oxide after anodizing. For filling with Si oxide, a solution containing a compound having a Si—O bond is applied, or a sodium silicate aqueous solution (No. 1 sodium silicate or No. 3 sodium silicate, 1 to 5 mass% aqueous solution, 20 to 70 ° C.) is 1 A method of immersing for ˜30 seconds, washing with water and drying, and further firing at 200 to 600 ° C. for 1 to 60 minutes is also possible.
As a chemically preferable method, in addition to the sodium silicate aqueous solution, the concentration of sodium fluoride zirconate and / or sodium dihydrogen phosphate alone or a mixed aqueous solution having a mixing ratio of 5: 1 to 1: 5 by weight It is also possible to use a method of performing a sealing treatment by immersing in a liquid of 1 to 5% by mass at 20 to 70 ° C. for 1 to 60 seconds.

<Insulating light reflecting substrate (LED substrate)>
Preferred examples of the insulating light reflecting substrate of the present invention are shown in cross-sectional views in FIGS.
In the insulating light reflecting substrate 30 of the present invention shown in FIG. 3, the entire surface of the core material 1 is coated with an aluminum alloy to form an aluminum alloy coating layer 3, and an aluminum alloy plate 5 is bonded to at least one surface thereof and bonded together. At least one surface of the aluminum alloy plate layer is roughened to obtain a roughened surface 9. Furthermore, it has an anodized film 7 that anodizes the roughened surface 9 to form a roughened surface.
FIG. 4 shows an insulating light reflecting substrate 40 according to another embodiment of the present invention, in which an aluminum alloy coating layer 3 is obtained in the same manner as in FIG. 3, and an aluminum alloy plate 5 is bonded to and bonded to at least one surface thereof. At least one surface of the alloy plate layer is roughened to obtain a roughened surface 9. Further, the insulating light reflecting substrate 40 has the anodized film 7 on the entire surface by anodizing all the aluminum alloy surfaces including the roughened surface 9.
The requirements for the LED substrate are insulation and light reflectivity. Further, even if the insulating light reflecting substrate of the present invention is placed in a heated atmosphere, the flatness of the substrate does not deteriorate and the insulating property of the substrate does not deteriorate.
The insulating light reflecting substrate of the present invention has an insulating layer that is an anodic oxide film, a metal layer in contact with the insulating layer formed on the roughened surface, and light reflection of light having a wavelength of more than 320 nm to 700 nm. The rate is 50% or more, and the light reflectance at a wavelength of 300 nm to 320 nm is 60% or more. Here, the total reflectance is measured by, for example, a spectrophotometer.

[1. Surface shape]
It is preferable that the surface of the insulating light reflecting substrate used in the present invention has irregularities with an average wavelength of 0.01 to 100 μm in order to satisfy the above reflectance. Moreover, you may take the shape where the unevenness | corrugation of a different wavelength was superimposed.
When the surface of the light reflecting substrate of the present invention has such irregularities, it is presumed that the light diffusion effect can be improved and the light emission absorption effect / interference effect (effect that can be a loss as reflection) can be suppressed. For this reason, the light reflection board | substrate of this invention is excellent in the light reflectivity.
Concavities and convexities (hereinafter also referred to as “large wave structure”) having an average wavelength of 5 to 100 μm are preferably an average wavelength of 7 to 75 μm and more preferably an average wavelength of 10 to 50 μm in terms of improving the light scattering effect. More preferred.
The surface of the light reflecting substrate of the present invention preferably has a structure having either the above-described unevenness or the following unevenness.
Concavities and convexities (hereinafter also referred to as “medium wave structure”) having an average wavelength of 0.5 to 5 μm have an average wavelength of 0.7 to 4 μm in that light scattering properties are increased and the light absorption effect is suppressed. It is preferable that the average wavelength is 1 to 3 μm.
Concavities and convexities (hereinafter also referred to as “small wave structure”) having an average wavelength of 0.01 to 0.5 μm are preferable to have an average wavelength of 0.015 to 0.4 μm in terms of suppressing the interference effect of visible light. More preferably, the wavelength is 0.02 to 0.3 μm.
The surface of the light reflecting substrate of the present invention has at least one selected from the group consisting of the above-described large wave structure, medium wave structure, and small wave structure. It is preferable to have the above superimposed, and it is more preferable to have all three superimposed.

Here, the measurement method of the average wavelength of the unevenness obtained by the roughening treatment may be, for example, the method described in the embodiment of the present invention, and as another method, the average wavelength of the small wave structure is roughened. From the direction perpendicular to the surface, an SEM photograph at a magnification of 30000 is taken using a scanning electron microscope (S-900, manufactured by Hitachi, Ltd.). In the SEM photograph, the shape that can identify the outline surrounding the recess is a pit, and the average value of the major axis and the minor axis is 1.0 μm or less, and the pit that does not further include a pit is a small wave. However, the micropore recess caused by the anodized film is excluded from the pits at this time. The average value of 100 waves is taken as the average wavelength of the wavelet.
The average wavelength of the large wave structure and the medium wave structure was observed with a scanning electron microscope JSM5500 manufactured by JEOL Ltd., tilted 30 degrees from the normal direction, and observed at a magnification of 2000 times. Measure unevenness components of 6 μm or more and less than 5 μm in the horizontal direction at 30 points, and set the average value of each to the average wavelength of the large wave structure and medium wave structure.

[2. Formation of light reflecting surface (roughening and anodizing)
The light reflecting surface is formed by anodizing after the following roughening treatment. Since the anodizing treatment is the same as the above treatment, the roughening treatment will be described below.
<Surface treatment>
The surface treatment for producing the insulating light reflecting substrate of the present invention includes a roughening treatment and an anodizing treatment. The surface treatment step may include various steps other than the surface roughening treatment and the anodizing treatment.
As a typical method for forming the surface shape described above, a method of sequentially performing mechanical surface roughening treatment, alkali etching treatment, desmutting treatment with an acid and electrochemical surface roughening treatment using an electrolytic solution on an aluminum plate, A method of performing mechanical surface roughening treatment, alkali etching treatment, acid desmutting treatment and electrochemical surface roughening treatment using different electrolytes on an aluminum plate a plurality of times, alkali etching treatment, acid desmutting treatment on an aluminum plate, and Examples include a method of sequentially performing an electrochemical surface roughening treatment using an electrolytic solution, a method of subjecting an aluminum plate to an alkali etching treatment, a desmutting treatment with an acid, and an electrochemical surface roughening treatment using different electrolytic solutions multiple times. However, the present invention is not limited to these. In these methods, after the electrochemical roughening treatment, an alkali etching treatment and an acid desmutting treatment may be further performed.

Among them, although depending on the conditions of other treatments (alkali etching treatment, etc.), in order to form a surface shape on which a large wave structure, a medium wave structure and a small wave structure are superimposed, a mechanical surface roughening treatment and nitric acid are mainly used. Preferred examples include a method of sequentially performing an electrochemical surface roughening treatment using an electrolytic solution and an electrochemical surface roughening treatment using an electrolytic solution mainly composed of hydrochloric acid. In addition, in order to form a surface shape in which a large wave structure and a small wave structure are superimposed, an electrolytic solution mainly composed of hydrochloric acid is used, and only an electrochemical surface roughening process is performed in which the total amount of electricity involved in the anode reaction is increased. Are preferable.
Details of each of the above roughening treatments are described in Japanese Patent Application No. 2010-010820.

<Manufacturing method of semiconductor substrate>
When the metal composite substrate of the present invention is used as a substrate for a semiconductor device, it is sized to a size necessary for each process, if necessary. Also, the side or bottom surface aluminum or aluminum alloy or anodized aluminum or aluminum alloy may be removed by melting or cutting, and the core material or aluminum may be exposed on some surfaces, Such a case is also included in the metal composite substrate of the present invention.

<Method for manufacturing solar cell>
Solar cells are roughly classified into three types: (1) single-crystal Si solar cells, (2) polycrystalline Si solar cells, and (3) thin-film solar cells. When a flexible metal composite substrate as in the present invention is used, it is suitable for use in a thin film solar cell. As a thin film type solar cell, two types, a thin film Si type and a compound type, are typical depending on the type of the light absorption layer.
The thin film Si type is a method of providing a thin film of amorphous Si or microcrystalline Si by a CVD method or the like, and GaAs type solar cells, CIS (calcobylite type) type solar cells, etc. are known as compound types. The CIS type is a solar cell that uses a compound such as Cu, In, Ga, Se, or S instead of Si, and has an abbreviation such as CIS, CIGS, or CIGSS depending on the compound.

FIG. 6 is a cross-sectional view showing an example of a general configuration of the thin-film solar cell 11 that can use the metal composite substrate of the present invention.
The entire surface of the core material 1 is coated with an aluminum alloy to form an aluminum alloy coating layer 3, an aluminum alloy plate 5 is bonded to at least one surface thereof, and an anodized film 7 is formed on at least one surface of the laminated aluminum alloy plate layer. The metal composite substrate 10 of the present invention having the insulating layer 13 is used as a substrate. Further, the back electrode layer 14 is laminated through the insulating layer 13, and the light absorption layer 15, the buffer layer 16, and the transparent electrode layer 17 are sequentially laminated, and the extraction electrodes 18 and 19 are placed on the transparent electrode layer 17 and the back electrode layer 14. Are stacked. Further, the exposed portion of the transparent electrode layer 17 is covered with an antireflection film 21.
In the thin film solar cell illustrated in FIG. 6, the material and thickness of the back electrode layer 14, the light absorption layer 15, the buffer layer 16, the transparent electrode layer 17, and the extraction electrodes 18 and 19 are not limited at all. For example, in a thin film solar cell using CIS or CIGS, each layer can be exemplified by the following materials and thicknesses.
The material of the back electrode layer 14 is a conductive material and has a thickness of 0.1 to 1 μm. For the lamination, a method generally used for manufacturing a solar cell may be used, and for example, a sputtering method, a vapor deposition method, or the like may be used. The material is not particularly limited as long as it has electrical conductivity. For example, a metal or semiconductor having a volume resistivity of 6 × 10 ⁶ Ω · cm or less may be used. Specifically, for example, Mo (molybdenum) may be stacked. The shape is not particularly limited, and may be laminated in an arbitrary shape according to the shape necessary for the solar cell.

<Thin film solar cell>
Thin film solar cells can be manufactured by a roll-to-roll method. That is, the metal composite substrate formed to have a predetermined thickness and wound on a roll is formed with each layer described later while being wound around the winding roll from the winding roll, or each layer is formed every winding. Is done.
In the production of the metal composite substrate of the present invention, it is particularly preferable that the anodizing treatment and the sealing treatment are performed by a roll-to-roll process.
Thereafter, the metal composite substrate that has been wound up by performing the above-mentioned treatment is re-delivered to form each layer to be described later in order to form a solar cell, and then cut to form a solar cell. Further, a method of cutting after anodizing treatment and sealing treatment and then forming a solar cell is also preferable.

<Examples and Comparative Examples>
The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these specific examples. Unless otherwise indicated,% in the following examples is mass%.
A metal material (stainless steel and steel) having a thickness of 100 μm was used as a core material, and an aluminum alloy having a thickness of 25 μm was provided on the entire surface by a hot dipping method. The aluminum used for hot dipping was examined for three levels of Al purity = 99.99%, 99.9%, and 99%.
As the core material, three levels of stainless steel SUS304, heat resistant steel SUH309, and mild steel SS400 were examined.
In this embodiment, an aluminum plate having a thickness of 50 μm was attached to each hot dipped material by clad rolling (total thickness of composite metal body: 0.2 mm). The rolling speed was 4 m / min. The aluminum plate has two levels of Al purity = 99.99% and 99.9%, and a raw material of Mg with an Al purity of 99.99% and Mg, and a total of 3 materials of Al 95.4% + Mg 4.5%. The level was examined.
In Comparative Examples 1 to 3, the above core material was plated with three levels of aluminum by hot dipping and the subsequent aluminum alloy plate was not attached (clad rolling), but the hot dipped thickness was 50 μm on the substrate surface. did.
In Comparative Example 4, aluminum plate (thickness: 0.1 mm) having a purity of 99.9% was pasted on the same core material as that of the example by clad rolling, without performing hot dipping as a coating layer of an aluminum alloy.
In Comparative Examples 5 to 7, each level of Al plate (thickness 0.2 mm) itself was used as the substrate.

(1) Production and Evaluation of Metal Composite Substrate The surface of each plate was finished to Ra = 0.05 μm by rolling with a mirror roll.
First, the surface was washed with 15% sulfuric acid at a liquid temperature of 30 ° C. for 10 seconds, washed with water, and anodized by direct current in oxalic acid (1 mol / L solution) to form a 20 μm anodic oxide film. , Washed with water.
Each substrate was bent 180 degrees to split the anodized film, and the fracture surface was similarly observed with an electron microscope to measure the thickness of the anodized film.
In Examples 1, 2, 3, 4, 5, and 6 of the composite metal body and Comparative Examples 1, 2, 3, 5, 6, and 7, the anodic oxide film could be formed. Dissolution progressed at the interface between the core material and the aluminum at the end face, and the problem was that the surface anodized film was insufficient in thickness and the end face was melted.

Evaluation 1
About each of the above Examples 1-6 and Comparative Examples 1-3, 5-7, after washing with sulfuric acid and washing with water, oxalic acid anodizing treatment (film thickness = 20 μm) and washing with water were carried out.
Next, each sample was cut out to a size of 300 mm × 300 mm, and surface insulation evaluation was performed at 100 locations. Insulation was judged as acceptable when the resistance value was 1 MΩ or more. In the case of 1 to 10 MΩ, the case of 10 MΩ or more is marked as ◎, and the case of less than 1 MΩ is marked as x. Insulation was measured before and after heating at 550 ° C. for 30 minutes.
The flatness after heating was evaluated on a glass surface plate at room temperature. For flatness, the amount of lift was measured with a gold scale. For those with a lift of 3 mm or less, measurement was made using a taper gauge. Table 2 shows the results.
The presence or absence of cracks in the anodized film after heating was visually inspected. ○ when there is no crack. The case where cracks occurred even at one location was marked as x.

In each of Examples 1 to 6, the flatness after heating and the insulation before and after heating were good, and in particular, Example 1 in which a 99.99% Al material plate was bonded with clad, and Al 95.4% + Mg 4.5% The material of Example 6 in which the material plate was bonded with clad had good insulation even after heating. There was no cracking after heating.
In Comparative Examples 1 and 2, the insulation before heating is within the target, but the insulation after heating decreases. When aluminum is plated by hot dipping, aluminum mixed with impurities from the core material and plating tank becomes the outermost layer, so even after anodic oxidation, impurities are mixed into the anodic oxide film and insulation resistance decreases. This is because. This tendency becomes remarkable after heating. This is presumably because the impurity element diffuses due to heating.
In Comparative Example 3, since the aluminum purity of hot dip plating is low, the insulating property is lowered before heating.
Since Comparative Examples 5, 6, and 7 did not have a core material, they could not withstand high-temperature treatment, and distortion and warpage occurred, resulting in reduced flatness. After heating, cracks also occurred in the anodized film.

(2) Manufacture and Evaluation of Solar Cell Next, a CIGS type solar cell was created using a metal composite substrate (0.3 mm × 300 mm × 300 mm) that passed the insulation. The same substrate as in Examples 1, 2, 3, 4, 5, 6 and Comparative Examples 5, 6, 7 was used as the substrate. It was prepared by the same method as described in paragraphs 244 and 245 of Japanese Patent Application Laid-Open No. 2009-267337. First, an approximately 1 μm Mo electrode was formed on one side by vapor deposition. Furthermore, a CIGS layer was provided, and subsequently a transparent electrode made of about 1 μm of ZnO was provided to manufacture a solar cell. In order to confirm that it functions as a solar cell, a part of the coating was cut, the Mo electrode layer was exposed, and whether or not it was possible to generate power with sunlight was measured between the surface ZnO electrode layer and a surface layer using a tester.
At that time, Comparative Examples 8 and 9 were in the middle of Mo film formation, and Comparative Example 10 was unable to be finished into a solar cell due to a problem that the plate warped in the middle of CIGS film formation and cracked on the surface. Table 3 shows the results.

(3) Production of Insulating Light Reflecting Substrate Using the same materials of Examples and Comparative Examples as in Table 1, the substrate was subjected to the following roughening treatment to obtain the insulating light reflecting substrate shown in Table 3.
1) Alkaline etching treatment The composite metal bodies obtained in the above examples and comparative examples are subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 2.6 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C. The aluminum plate was dissolved at 6 g / m ² . Then, water washing by spraying was performed.
2) Desmut treatment Desmut treatment was performed by spraying with a 1% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

3) Electrochemical roughening treatment An electrochemical roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 10.5 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by mass of ammonium ions) at a liquid temperature of 50 ° C. The AC power supply waveform is a trapezoidal wave (see Fig. 1 of Japanese Patent Application No. 2010-010820). The time TP until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, and the trapezoidal rectangular wave AC is used. An electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The electrolytic cell used was the one shown in FIG. 2 of Japanese Patent Application No. 2010-010820. The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. Then, water washing by spraying was performed.

4) Alkaline etching treatment The aluminum plate was spray-etched at 32 ° C. using an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% to dissolve the aluminum plate by 0.3 g / m ^2. The smut component mainly composed of aluminum hydroxide generated when the electrochemical surface roughening treatment was performed using AC was removed, and the edge portion of the generated irregularities was dissolved to smooth the edge portion. . Then, water washing by spraying was performed.
5) Desmut treatment The desmut treatment was performed by spraying with a 15% by weight aqueous solution of sulfuric acid at a temperature of 30 ° C (containing 4.5% by weight of aluminum ions), and then washed with water by spraying.
6) Anodizing treatment Anodizing treatment was performed using an anodizing apparatus having a structure shown in FIG. Oxalic acid was used as the electrolytic solution supplied to the first and second electrolysis units. All of the electrolyte solutions had an oxalic acid concentration of 60 g / L (containing 0.5 mass% of aluminum ions) and a temperature of 38 ° C. Then, water washing by spraying was performed. The final oxide film thickness was 10 μm.
(4) Manufacture and evaluation of LED element mounting unit The insulating light reflecting substrate obtained above was evaluated, and the results are shown in Table 4.
In Example 13, the substrate of Example 1 was used, and after the surface was whitened by subjecting 99.99% aluminum clad and rolled to the outermost layer, the surface of the anodic oxide film to be formed was uniform. Because of its particularly excellent properties, it showed high brightness with little light loss.
Examples 14-18 were also good results because a uniform anodized film was formed after the whitening treatment was performed.
In Comparative Example 11-13, cracking occurred when the LED was mounted due to heating during wiring processing, and the light emission test was not achieved.
The total reflectance of the light reflecting surfaces after roughening in Examples 13 to 18 was all 60% or more, and had irregularities in the average wavelength range of 0.01 to 100 μm. The total reflectance of Comparative Example 14 was less than 50%.

(5) Luminance evaluation Using the light reflecting substrates of the examples and comparative examples obtained as described above, the luminance evaluation of the phosphor-mixed white LED light emitting unit was performed as follows.
That is, the light reflecting substrate of each example and comparative example is provided as the light reflecting substrate 140 in contact with the blue LED 110 of the light emitting unit 100 shown in FIG. 7, and each light emitting unit when the blue LED 110 is driven at 6V is provided. The brightness was compared.
The substrate of Comparative Example 14 uses the composite metal body of Example 1 of Table 1 and does not perform the surface roughening treatments 1) to 5), but uses the substrate subjected to only the anodic oxidation treatment 6). Similarly, an LED unit was manufactured.
As a result, the light emitting unit using the insulating light reflecting substrate of Example 13 was 1.1 to 1.3 times as bright as the light emitting unit using the substrate of Comparative Example 14. .

DESCRIPTION OF SYMBOLS 1 Core material 2 Composite metal body 3 Covering layer 5 Arminium alloy plate 7 Anodized film 9 Roughened surface 10, 20 Metal composite substrate 30, 40 Insulating light reflecting substrate 11 Thin film solar cell 13 Insulating layer 14 Back electrode layer 15 Light absorption layer 16 Buffer layer 17 Transparent electrode layers 18 and 19 Extraction electrode 21 Antireflection film 20 Pass roll 22 Electrolytic solution 24 Feed tank 25 Oxidation tank 26 DC power supply 28 Anode 30 Cathode

Claims (14)

  A metal having a coating layer made of aluminum or an aluminum alloy on the entire surface of a core material made of a metal having a heat resistance higher than aluminum at 300 ° C. or higher, and an aluminum plate or an aluminum alloy plate on at least one surface of the coating layer A metal composite substrate having an anodized film on at least one surface of an aluminum plate or an aluminum alloy plate of the metal composite substrate.   The metal composite substrate according to claim 1, wherein the core material is steel.   The metal composite substrate according to claim 1, wherein the anodized film is provided on the entire surface of the metal composite substrate.   The metal composite substrate according to claim 1, wherein the anodized film is a porous anodized film having a thickness of 1 to 200 μm.   The metal composite substrate according to claim 1, wherein the anodized film is subjected to a sealing treatment.   An insulating metal substrate comprising the metal composite substrate according to claim 1.   The anodized film of the metal composite substrate according to any one of claims 1 to 5 is an insulating light reflecting substrate having a light reflecting surface, and the light reflecting surface has a total reflectance of light having a wavelength of more than 320 nm to 700 nm. %, And the total reflectance of light having a wavelength of 300 nm to 320 nm is 60% or more.   The insulating light reflecting substrate according to claim 7, wherein the light reflecting surface has irregularities having an average wavelength of 0.01 to 100 μm.   9. A white light emitting diode device comprising a blue light emitting element on an upper part of a light reflecting surface of a light reflecting substrate according to claim 7 or 8, and a fluorescent light emitting element around and / or above the light emitting element.   A semiconductor substrate comprising the metal composite substrate according to claim 1.   A thin-film solar cell in which a light absorption layer and an electrode layer are formed on the metal composite substrate according to claim 1.   The light absorption layer is formed on the metal composite substrate through a back electrode layer, and the light absorption layer contains any one compound of CdS / CdTe, CIS, and CIGS. Thin film solar cells.   A core material made of a metal having a heat resistance higher than aluminum at 300 ° C. or higher is coated with aluminum or an aluminum alloy on the entire surface, and an aluminum plate or an aluminum alloy plate is formed on at least one surface of the resulting aluminum or aluminum alloy layer. A method for producing a metal composite substrate, in which at least one surface of an aluminum plate or an aluminum alloy plate obtained is anodized, washed with water, and dried.   The method for manufacturing a metal composite substrate according to claim 13, wherein the coating is hot-dip plating.