JP2013154392A - Aluminum structure, manufacturing method thereof, aluminum structure assembly, aluminum wiring board, semiconductor system, and solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum structure capable of being suitably soldered to an aluminum base body made from an aluminum only or an aluminum alloy in spite of a simple structure.SOLUTION: An aluminum structure 1 has a soldering section 3 for soldering to an aluminum surface 2a of the aluminum base body 2 made from the aluminum only or the aluminum alloy. The soldering section 3 has a metal layer section 4 made from metal except aluminum which can make an alloy with a solder, on the aluminum surface 2a. The layer thickness of the metal layer section 4 is a layer thickness capable of being penetrated by the solder in a layer thickness direction by making the metal layer section 4 melt into the solder at the time of soldering.

Description

  The present invention relates to an aluminum structure, a manufacturing method thereof, an aluminum structure assembly, an aluminum wiring board, a semiconductor device, and a solar cell module.

Conventionally, for example, metals such as copper, gold, and silver have been used for wiring of electric circuits, but instead of these metals, cheaper aluminum or aluminum alloy (hereinafter simply referred to as aluminum) is substituted. It is being considered.
When aluminum is left in the air, the surface is covered with an aluminum oxide film. If this oxide film exists, soldering becomes very difficult. For this reason, various techniques for soldering to aluminum have been studied.
For example, Patent Document 1 proposes that after the oxide film is removed, metal plating that is easy to solder is applied to the surface. That is, oil is removed from the surface of the object to be processed, which is a plurality of aluminum bus bars, the oxide on the surface of the object to be processed is removed with a strong alkaline solution, and then the surface of the object to be processed is activated with a nitric acid solution. An aluminum bus bar plating method is described in which zinc plating, copper plating, and tin plating are applied in this order to the surface of the body.
In this way, multi-layer plating with a plurality of metals is performed because the adhesion strength of the plating with respect to aluminum is small in the metal plating with high solder wettability and suitable for soldering. It is necessary to go through.
In Patent Document 2, any one of a first metal layer containing aluminum, a second metal layer containing titanium, a third metal layer containing nickel, copper, tin, and titanium is formed on a semiconductor substrate by sputtering. A semiconductor device having a back electrode in which a fourth metal layer containing s is laminated in this order is described.
As described above, even when the metal layers are laminated by sputtering, the multi-layer structure has sufficient adhesion strength to aluminum even if the uppermost metal layer having good solder wettability is sputtered directly onto aluminum. This is because it cannot be obtained.

JP 2010-285652 A JP 2010-171141 A

The prior art as described above has the following problems.
In the techniques described in Patent Documents 1 and 2, in order to join the uppermost metal layer with good solder wettability to aluminum with high strength, a plurality of intermediate layers are laminated between aluminum. There is a need. As described above, when a multilayer intermediate layer is formed, the number of steps increases, and thus there is a problem that the manufacturing cost increases.

The present invention has been made in view of the above problems, and an aluminum structure capable of satisfactorily soldering to an aluminum base portion made of a single aluminum or an aluminum alloy even with a simple configuration. An object of the present invention is to provide a manufacturing method thereof and an aluminum wiring board.
Another object of the present invention is to provide an aluminum structure assembly, a semiconductor device, and a solar cell module that are easy to manufacture and can reduce manufacturing costs.

  In order to solve the above-mentioned problems, the invention according to claim 1 is an aluminum structure having a solder joint for soldering on the surface of an aluminum base part made of aluminum alone or an aluminum alloy. The solder joint portion includes a metal layer portion made of a metal other than aluminum capable of forming an alloy with solder on the surface of the aluminum base portion, and the thickness of the metal layer portion is determined when the metal layer portion is soldered. Is dissolved in the solder so that the solder can be penetrated in the layer thickness direction.

  According to a second aspect of the present invention, in the aluminum structure according to the first aspect, the metal layer portion is formed of a metal thin film that has a layer thickness of 1 nm to 50 nm and covers the surface of the aluminum base portion. It becomes the composition which becomes.

According to a third aspect of the present invention, in the aluminum structure according to the first aspect, the metal layer portion is dispersed in a lamellar region as metal particles in which the metal has a particle shape or a lump shape with a height of 1 nm to 100 nm. The area density of the metal in the layered region is 1 μg / cm ² or more and 100 μg / cm ² or less.

  In the invention according to claim 4, in the aluminum structure according to any one of claims 1 to 3, the metal in the metal layer portion is a noble metal than aluminum in the electrochemical column. To do.

  According to the fifth aspect of the present invention, in the method of manufacturing an aluminum structure, the method of manufacturing an aluminum structure having a solder joint for soldering on the surface of an aluminum base part made of aluminum alone or an aluminum alloy. The aluminum substrate part is immersed in a chemical solution to remove the aluminum oxide film on the surface of the aluminum substrate part, and the surface of the aluminum substrate part from which the aluminum oxide film has been removed In addition, a metal layer portion that forms a metal layer portion by adhering a metal other than aluminum that can form an alloy with solder to a layer thickness through which the solder penetrates in the layer thickness direction by dissolving the metal in the solder during soldering And a forming step.

  According to a sixth aspect of the present invention, in the method for manufacturing an aluminum structure according to the fifth aspect, in the metal layer portion forming step, the metal layer portion is formed by plating.

  According to a seventh aspect of the present invention, in the method for manufacturing an aluminum structure according to the sixth aspect, in the metal layer portion forming step, the plating solution used for the plating includes a halogen element.

  In the invention according to claim 8, in the aluminum structure assembly, the aluminum structure according to any one of claims 1 to 4 and the solder joint portion of the aluminum structure are joined by soldering. And a member to be joined.

  In the invention according to claim 9, the aluminum wiring board is provided with an electric circuit formed of the aluminum structure according to any one of claims 1 to 4.

  In a tenth aspect of the present invention, a semiconductor device includes the aluminum wiring board according to the ninth aspect and a semiconductor element soldered to the solder joint portion of the aluminum wiring board.

  According to an eleventh aspect of the present invention, a solar cell module includes the aluminum wiring board according to the ninth aspect and solar cells soldered to the solder joints of the aluminum wiring board.

According to the aluminum structure of the present invention, the manufacturing method thereof, and the aluminum wiring board, the solder joint portion is formed with the metal layer portion on the surface of the aluminum cloth, and the metal layer portion is dissolved in the solder during soldering. Since the layer thickness is such that the solder can penetrate in the direction of the layer thickness, even with a simple configuration, it is possible to satisfactorily perform soldering on an aluminum base part made of aluminum alone or an aluminum alloy. .
Moreover, since the aluminum structure assembly, the semiconductor device, and the solar cell module according to the present invention include the aluminum structure according to the present invention, there is an effect that the manufacturing is easy and the manufacturing cost can be reduced.

It is typical sectional drawing which shows schematic structure of the aluminum structure of the 1st Embodiment of this invention. It is process explanatory drawing which shows the manufacturing process of the aluminum structure of the 1st Embodiment of this invention. It is a schematic explanatory drawing explaining the effect | action of the aluminum structure of the 1st Embodiment of this invention. It is a schematic diagram which shows one form after soldering using the aluminum structure of the 1st Embodiment of this invention. It is typical sectional drawing which shows schematic structure of the aluminum structure of the 2nd Embodiment of this invention. It is process explanatory drawing which shows the manufacturing process of the aluminum structure of the 2nd Embodiment of this invention. It is a schematic explanatory drawing explaining the effect | action of the aluminum structure of the 2nd Embodiment of this invention. It is typical sectional drawing which shows the example of the aluminum structure assembly of the 3rd Embodiment of this invention. It is the photographic image which shows an example of the surface of the aluminum structure of the Example corresponding to the 2nd Embodiment of this invention, and the photographic image which shows an example of the surface of a comparative example.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
An aluminum structure according to the first embodiment of the present invention will be described.
FIG. 1 is a schematic cross-sectional view showing a schematic configuration of an aluminum structure according to a first embodiment of the present invention.

As shown in FIG. 1, the aluminum structure 1 of the present embodiment includes an aluminum base 2 made of a single aluminum or an aluminum alloy, and a solder joint for soldering to the aluminum surface 2 a of the aluminum base 2. 3.
Here, the simple aluminum means aluminum having a purity of 99% or more, and the aluminum alloy means an alloy containing 50% or more of aluminum. For example, examples of the aluminum alloy include an aluminum copper alloy, an aluminum silicon alloy, and an aluminum magnesium alloy.
Further, when the aluminum simple substance or the aluminum alloy is left in the air, the surface is oxidized to form an oxide film 5 (aluminum oxide film) made of aluminum oxide. It constitutes the outermost surface. Hereinafter, the surface of the aluminum base portion 2 in a state where the oxide film 5 is not formed is referred to as an aluminum surface 2a, in distinction from the oxide film surface 5a.

The use of the aluminum structure 1 is not particularly limited as long as it is used by soldering another member to be joined onto the solder joint portion 3.
Moreover, since the aluminum structure 1 of this embodiment can electrically connect a metal member and the aluminum base material part 2 when a metal member is soldered to the solder joint part 3, an electrical wiring, an electric circuit, etc. It is particularly suitable for That is, it can be used as an aluminum wiring board for soldering a lead wire, an electric element, an electronic component or the like (hereinafter sometimes collectively referred to as an electric component) to the solder joint portion 3.

The shape of the aluminum base portion 2 is not particularly limited, and may be, for example, a plate shape, a sheet shape, a foil shape, a rod shape, a cylindrical shape, a linear shape, a spherical shape, or any other appropriate three-dimensional shape depending on the application of the aluminum structure 1. The shape such as can be adopted. In addition, the aluminum base portion 2 draws an appropriate two-dimensional pattern such as a linear shape, a curved shape, a circular shape, a polygonal shape, a comb tooth shape, a loop shape, or a spiral shape on a flat surface or a curved surface. The shape can be changed.
Moreover, the aluminum base material part 2 may be a member that is used by itself, or is formed by being affixed, printed, or formed on the surface of a base member such as an insulating substrate. It may be what was done.
For example, when the aluminum structure 1 is used as an electric circuit in an aluminum wiring board, the aluminum base portion 2 is formed in a necessary circuit pattern and has a cross-sectional shape that provides good conductivity.

The solder joint portion 3 is a metal layer portion made of a metal other than aluminum capable of forming an alloy with the solder, and covers the aluminum surface 2a with a substantially uniform layer thickness, and also has a metal thin film 4 (metal layer portion) in close contact with the aluminum surface 2a. ).
As the kind of solder, for example, lead-free solder, eutectic solder or the like can be employed.
Moreover, it does not specifically limit as a soldering method, The method using a soldering iron, a solder flow apparatus, etc. can be used.

The thickness of the metal thin film 4 is set to a layer thickness H ₄ that allows the solder to penetrate in the layer thickness direction by dissolving the metal thin film 4 in the solder during soldering.
The thickness H _4, the solder volume and used, depending on the time required for soldering, for example, solder amount enough to perform soldering of the electrical components, the time is suitably 1nm or 50nm or less.
The layer thickness of the metal thin film 4 can be measured as an average thickness in the solder joint portion 3 by using, for example, a fluorescent X-ray film thickness meter.
The magnitude | size and shape of planar view of the metal thin film 4 can be suitably set according to the magnitude | size and shape of a to-be-joined member. For example, when the aluminum structure 1 is used as an aluminum wiring board, a shape similar to a land pattern for soldering formed of, for example, a copper foil on a printed board can be employed.

As the metal material for forming the metal thin film 4, any metal other than aluminum capable of forming an alloy with solder can be used. For example, nickel and copper are particularly suitable because they easily form an alloy with solder.
However, when the metal thin film 4 is formed by plating, it is necessary to use a metal that is nobler than aluminum in the electrochemical column. By satisfying this condition, the metal can be easily deposited on the aluminum surface 2a from which the oxide film 5 has been removed.
Many such metal materials are known. For example, gold, silver, palladium, tin, etc. can be mentioned besides the above nickel and copper.

Next, a method for manufacturing such an aluminum structure 1 will be described.
FIGS. 2A, 2B, 2C, and 2D are process explanatory views showing a manufacturing process of the aluminum structure according to the first embodiment of the present invention.

In order to manufacture the aluminum structure 1, the oxide film removing step and the metal layer portion forming step are performed in this order.
First, an oxide film removing process is performed. This step is a step of removing the oxide film 5 on the aluminum surface 2a of the aluminum base portion 2 by immersing the aluminum base portion 2 in the chemical solution.
Examples of the chemical solution for removing the oxide film 5 include alkali hydroxide such as sodium hydroxide, potassium hydroxide, and ammonia. Moreover, as an acidic example, hydrogen fluoride, hydrochloric acid, phosphoric acid etc. can be mentioned, for example. However, the chemical solution is not limited to these, and any appropriate alkaline or acidic chemical solution capable of removing aluminum oxide can be employed.
For example, as shown in FIG. 2B, an oxide base film 2 having an oxide film 5 formed on an aluminum surface 2a as shown in FIG. 2A is immersed in a sodium hydroxide solution. 5 can be removed.
This completes the oxide film removal step.

Next, after the aluminum substrate part 2 from which the oxide film 5 has been removed is washed in a deoxygenated atmosphere, a metal layer part forming step is performed.
This step is a step of forming the metal thin film 4 on the aluminum surface 2a of the aluminum base portion 2 from which the oxide film 5 has been removed.
In this step, the aluminum base portion 2 is placed in a deoxygenated atmosphere, and the metal thin film 4 is formed on the aluminum surface 2a by, for example, electroless plating, plating such as electrolytic plating, sputtering, or thermal spraying.
At this time, as shown by a two-dot chain line in FIG. 2 (c), a mask 6 is disposed in a region other than the region where the metal thin film 4 is formed on the aluminum surface 2a so that the metal thin film 4 is not formed. deep. As the mask 6, for example, a well-known mask member such as a plating mask or a solder resist or a mask process can be employed depending on the method of forming the metal thin film 4.
When the metal thin film 4 having a required layer thickness is thus formed, the film formation is stopped. Thereby, a metal part formation process is complete | finished.
Thereafter, the mask 6 is removed from the aluminum base 2 and cleaning is performed as necessary. At this time, the aluminum surface 2a and the metal thin film 4 are in close contact with each other, and the aluminum surface 2a and the metal thin film 4 are not oxidized. For this reason, it is possible to take out the work from the deoxidized atmosphere.
In this way, as shown in FIG. 2D, the aluminum structure 1 is manufactured.
The reason why the oxide film 5 is formed in FIG. 2D is that the aluminum surface 2a is naturally oxidized when it is taken out into the atmosphere and brought into contact with oxygen.

Next, the action of the aluminum structure 1 will be described focusing on the action during soldering.
FIGS. 3A, 3B, and 3C are schematic explanatory views illustrating the operation of the aluminum structure according to the first embodiment of the present invention. FIG. 4 is a schematic view showing an embodiment after soldering using the aluminum structure according to the first embodiment of the present invention.

  As shown in FIG. 3A, the aluminum structure 1 is soldered by disposing a solder melt 7 and a member to be joined (not shown) on the solder joint portion 3 and solidifying the solder melt 7. It can be carried out. In the following, in order to explain mainly the process of forming a joined state of the solder melt 7 with respect to the aluminum base portion 2, the member to be joined is not shown. The joining process between the member to be joined and the solder melt 7 is the same as in the case of conventional soldering.

When the solder is melted on the thin film surface 4a of the metal thin film 4 to form the solder melt 7, the metal material of the metal thin film 4 is a metal that can form an alloy with the solder. From 4a, the metal of the metal thin film 4 is dissolved in the solder melt 7 and diffuses into the solder melt 7 as metal atoms.
Since the amount of the solder melt 7 is sufficiently larger than the amount of the metal thin film 4, the melting of the metal thin film 4 proceeds as shown in FIG. Interface S expands within the thickness of the metal thin film 4.
Then, as shown in FIG. 3C, when the interface S reaches the aluminum surface 2a, the solder melt 7 and the aluminum surface 2a are in direct contact with each other.
As a result, the aluminum surface 2a and the solder melt 7 are brought into close contact with each other to form a tin aluminum alloy, which is firmly bonded.
When the heat dissipation of the solder melt 7 proceeds, the solder melt 7 becomes the solder solid body 7A, and the solder solid body 7A is joined to the aluminum surface 2a.
Further, at the interface S between the solder melt 7 and the metal thin film 4, since the metal thin film 4 forms an alloy with the solder, the solder solidified body 7 </ b> A is also in close contact with the metal thin film 4.
Thus, since the solder solid body 7A is closely bonded to the metal thin film 4 and the aluminum surface 2a and an alloy is formed at each interface, good bonding strength and electrical conductivity can be obtained.

FIG. 3C illustrates an example in which soldering is completed with the solder melt 7 penetrating in the layer thickness direction in a part of the metal thin film 4. When nickel is used as the material, the bonding strength between the metal thin film 4 and the aluminum surface 2a is smaller than the bonding strength between the solder solidified body 7A and the aluminum surface 2a. Compared to the case where the body 7A is bonded to all the aluminum surfaces 2a on the solder joint portion 3, the bonding strength is lowered.
For this reason, it is preferable to make the residual amount of the metal thin film 4 as small as possible by appropriately setting the amount of solder and the metal amount determined by the area and layer thickness of the metal thin film 4.

FIG. 4 shows a case where the entire amount of the metal thin film 4 is dissolved in the solder melt 7 and the solder solid body 7A is formed in the entire region of the solder joint 3 by appropriately adjusting the amount of solder and the amount of metal of the metal thin film 4. A cross-sectional shape is shown.
In this case, since the oxide film 5 is usually formed in a region adjacent to the metal thin film 4, the solder melt 7 does not advance onto the oxide film 5. Therefore, the solder melt 7 is solidified within the range of the shape in plan view where the metal thin film 4 is formed, and becomes a solder solid 7A.
In such a joining form, the aluminum surface 2a and the solder solid body 7A are directly joined in the entire region of the solder joint portion 3, and the joining strength with the aluminum surface 2a as the metal material of the metal thin film 4 is too high. Even if no metal is used, good soldering can be performed. Thereby, the freedom degree of selection of the metal material of the metal thin film 4 becomes wide.

As described above, according to the aluminum structure 1, when soldering is performed at the solder joint portion 3, at least a part of the metal thin film 4 is dissolved in the layer thickness direction. And directly joined. Thereby, favorable soldering can be performed to the aluminum base material part 2.
Since the metal thin film 4 only needs to form a single-layer thin film having a thickness of 1 nm or more and 50 nm or less using one type of metal material, the manufacturing process is simplified as compared with the conventional technique in which a plurality of intermediate layers are formed. . Thereby, the manufacturing cost can be reduced.
Moreover, in the joining by a plurality of intermediate layers, the solder is joined only to the uppermost layer, and the aluminum base part is only indirectly joined, so that the joining characteristics (joining strength, The electrical resistance) depends on the junction characteristics between the respective layers. On the other hand, according to the aluminum structure 1 of the present embodiment, since the solder solid body 7A and the aluminum surface 2a are directly bonded, the bonding characteristics can be improved.

[Second Embodiment]
An aluminum structure according to a second embodiment of the present invention will be described.
FIG. 5 is a schematic cross-sectional view showing a schematic configuration of an aluminum structure according to the second embodiment of the present invention.

As shown in FIG. 5, the aluminum structure 11 of the present embodiment includes a solder joint portion 13 instead of the solder joint portion 3 of the first embodiment. Moreover, the metal particle body 14 can be used for the same use as the aluminum structure 1 of the said 1st Embodiment.
Hereinafter, a description will be given centering on differences from the first embodiment.

  The solder joint portion 13 is formed on the aluminum surface 2a of the aluminum base portion 2 by a metal layer portion in which a metal particle 14 in which a metal other than aluminum capable of forming an alloy with solder is formed in a particle shape or a lump shape is dispersed in a layer region. Has been.

The shape of the metal particle 14 is not particularly limited as long as it is a particle shape or a lump shape in which a plurality of metal atoms are bonded in a crystallized or amorphous state. Although FIG. 5 is a schematic diagram, the metal particles 14 are drawn in a spherical shape, but an appropriate outer shape including a spherical shape can be adopted.
That is, the metal particles 14 may be dispersed in the form of particles having substantially the same size, or may be dispersed in the form of elongated particles having different major and minor diameters. Good.
Moreover, the block-shaped thing which has an irregular external shape may be disperse | distributed.
Moreover, if it has the some metal particle 14, the one metal particle 14 may consist of the lump which the some particle metal connected mutually, and was integrated closely, You may consist of the lump body integrated porous.

In addition, the metal particles 14 are in contact with the protrusion 14a of the metal particles 14 protruding outside the oxide film 5 and at the surface opposite to the protrusion 14a in at least a part of the solder joint 13. The portion 14b is formed in close contact with the aluminum surface 2a. The contact portion 14 b can be in a dot-like, linear, or planar contact state according to the shape of the metal particle 14.
Further, the height of the metal particles 14 from the aluminum surface 2a is a height H _{14 at} which the solder can penetrate from the top of the protrusion 14a to the contact portion 14b when the metal particles 14 are dissolved in the solder during soldering. It is said that.
Here, the top envelope surface of the protrusion 14 a of each metal particle 14 corresponds to the thickness of the metal layer portion formed by the metal particle 14.
The height H ₁₄ is the amount of solder and used, depending on the time required for soldering, for example, solder amount enough to perform soldering of the electrical components, the time is suitably 1nm or 100nm or less.
The degree of dispersion of the metal particles 14 is preferably such that the surface density of the metal particles 14 in the solder joint 13 is 1 μg / cm ² or more and 100 μg / cm ² or less. Here, the areal density represents mass per unit area.
For example, when the metal particles 14 are spheres having a diameter of 100 nm and are densely packed on the solder joint portion 13, if a similar metal amount is to be realized with the metal thin film 4, the layer thickness is about 50 nm. , the numerical range of H ₁₄ as the metal amount is adapted to a suitable thickness substantially equal to the metal thin film 4. Moreover, the upper limit of 100 μg / cm ² or less of the preferable range of the surface density is substantially equal to the case where the metal thin film 4 has a layer thickness of 50 nm when the metal particles 14 are nickel. (

In addition, it is difficult to accurately measure the height of the fine metal particles 14 as in this embodiment, but as described above, the height is determined according to the height, particle diameter, and distribution state of the metal particles 14. It is important to control the abundance as a metal. For this reason, it is possible to substitute for measuring the average thickness at the solder joint portion 13 by using a fluorescent X-ray film thickness meter, for example, when determining the plating conditions. That is, the above-mentioned height H ₁₄ and surface density conditions, the average layer thickness but it can be replaced as 1nm or 50nm or less.
In addition, since the particle diameter and the like of the metal particles 14 can be measured by using an electron microscope, it is possible to evaluate whether or not the metal particles 14 having a suitable distribution state are formed by using them together. is there.

As the metal material for forming the metal particles 14 and the method for forming the metal particles 14, the same metal material and method as those for the metal thin film 4 of the first embodiment can be employed.
However, a particularly preferable method for forming the metal particles 14 is plating, and it is preferable to employ a material suitable for plating as the metal material.

Next, a method for manufacturing such an aluminum structure 11 will be described.
6 (a), 6 (b), 6 (c), and 6 (d) are process explanatory views showing the manufacturing process of the aluminum structure according to the second embodiment of the present invention.

In order to manufacture the aluminum structure 11, the oxide film removing step and the metal layer portion forming step are performed in this order.
As shown in FIGS. 6A and 6B, the oxide film removing process of the present embodiment is exactly the same as the oxide film removing process of the first embodiment.
Also, the aluminum substrate part 2 from which the oxide film 5 has been removed is washed in a deoxygenated atmosphere before the start of the metal layer part forming process, as in the first embodiment.

Next, the metal layer part formation process of this embodiment is performed.
This step is a step of forming a metal layer portion by the metal particles 14 on the aluminum surface 2a of the aluminum base portion 2 from which the oxide film 5 has been removed. The metal particles 14 can be formed by sputtering, thermal spraying, or the like. Hereinafter, an example of a process using plating that can be more easily manufactured will be described.

In this step, the aluminum base portion 2 is disposed in a deoxygenated atmosphere, and the area outside the region where the solder joint portion 13 is formed is covered with a mask 6 (see FIG. 6C), as in the first embodiment. In the state, it is immersed in a plating solution containing a halogen element and a metal salt of a metal forming the metal particles 14. Here, the reason why the halogen element is included in the plating solution is to dissolve the aluminum oxide even when the aluminum oxide is generated in the work after the oxide film removing step, and to proceed the plating smoothly.
As a result, as shown in FIG. 6B, the halogen compound dissolves the aluminum oxide, and the metal particles 14 are deposited on the aluminum surface 2a by the substitution reaction between the aluminum and the metal.
When the metal particles 14 are thus formed to the required height and surface density, the plating is stopped. Thereby, the metal part formation process of this embodiment is complete | finished.
The time until the plating is stopped can be determined in advance by conducting an experiment in which the plating time is changed in advance, and measuring the height, surface density, and particle size of the metal particles 14.
Thereafter, the mask 6 is removed from the aluminum base portion 2 and cleaning is performed. At this time, since the aluminum surface 2a and the contact portion 14b of the metal particle 14 are in close contact with each other and the space between the aluminum surface 2a and the contact portion 14b is not oxidized, the work is taken out from the deoxygenated atmosphere. It is possible.
In this way, as shown in FIG. 6D, the aluminum structure 11 is manufactured.
The reason why the oxide film 5 is formed in FIG. 6D is that, as in the first embodiment, when it is taken out into the atmosphere, it is naturally oxidized and the oxide film 5 is formed.

Next, the action of the aluminum structure 11 will be described focusing on the action during soldering.
7A, 7B, and 7C are schematic explanatory views for explaining the operation of the aluminum structure according to the second embodiment of the present invention.

  As shown in FIG. 7A, the aluminum structure 11 is soldered by disposing the solder melt 7 on the solder joint portion 13 and disposing an unillustrated member to be joined in the solder melt 7. It can be performed. However, as in the description of the first embodiment, the members to be joined are not shown.

When the solder is melted on the solder joints 13 including the protrusions 14a of the metal particles 14 to form the solder melt 7, the metal particles 14 are connected to the solder melt 7 in the same manner as in the first embodiment. From the abutting protrusion 14 a, it dissolves in the solder melt 7, and the metal atoms of the metal particles 14 diffuse into the solder melt 7.
Since the solder melt 7 is sufficiently larger than the amount of the metal particles 14, as shown in FIG. 7B, the metal particles 14 in contact with the solder melt 7 (for example, the illustrated metal particles 14A and the like). ) Progresses and the interface S between the solder melt 7 and the metal particles 14 in which the metal atoms are dissolved spreads in the metal particles 14.
However, since the oxide film 5 is not dissolved in the solder melt 7, the oxide film 5 surrounding the metal particles 14 remains as it is.
As shown in FIG. 7C, when the interface S reaches the contact portion 14b, the solder melt 7 and the aluminum surface 2a are in direct contact with each other.
As a result, the aluminum surface 2a and the solder melt 7 are brought into close contact with each other to form a tin-aluminum alloy at the position of the contact portion 14b, which is firmly joined.
When the heat dissipation of the solder melt 7 proceeds, the solder melt 7 becomes a solder solid body 7A, and is joined to the aluminum surface 2a in a state where the solder solid body 7A covers a part of the oxide film 5.
Thus, since the solidified solder body 7A is closely bonded to the aluminum surface 2a and an alloy is formed at the interface, good bonding strength and electrical conductivity can be obtained.

In FIG. 7C, the state in which all of the metal particles 14 in contact with the solder melt 7 are melted is depicted, but as in the first embodiment, some of the metal particles 14 are Alternatively, it may remain in contact with the solder solid body 7A. In this case, the metal particles 14 and the solder solid body 7A are soldered well.
In the present embodiment, since the metal particles 14 are formed in a dispersed manner, the dissolved metal atoms are likely to diffuse around the metal particles 14 in the solder melt 7. Compared to the case of the first embodiment in which the entire surface of 7 is in contact with the metal thin film 4, the dissolution can easily proceed efficiently.

Thus, according to the aluminum structure 11, when soldering is performed at the solder joint portion 13, at least a part of the metal particles 14 is melted in the height direction. 2a is directly joined. Thereby, favorable soldering can be performed to the aluminum base material part 2.
Since the metal particles 14 need only be formed in a single layered region using one kind of metal material, the manufacturing process is simplified as compared with the conventional technique in which a plurality of intermediate layers are formed. Thereby, the manufacturing cost can be reduced.
Moreover, in the joining by a plurality of intermediate layers, the solder is joined only to the uppermost layer, and the aluminum base part is only indirectly joined, so that the joining characteristics (joining strength, The electrical resistance) depends on the junction characteristics between the respective layers. On the other hand, according to the aluminum structure 11 of the present embodiment, since the solder solid body 7A and the aluminum surface 2a are directly bonded, the bonding characteristics can be improved.

[Third Embodiment]
An aluminum structure assembly according to a third embodiment of the present invention will be described.
FIG. 8 is a schematic cross-sectional view showing an example of an aluminum structure assembly according to a third embodiment of the present invention.

  The aluminum structures 1 and 11 of the first and second embodiments can form an aluminum structure assembly in which various members to be joined that can be soldered are joined.

The assembly 20 (aluminum structure assembly) shown in FIG. 8A is obtained by soldering the end 21a of the member 21 to be joined to the solder joint 3 (13) of the aluminum structure 1 (11). is there. For this reason, the member 21 to be joined is joined to the solder solid body 7A formed on the solder joint portion 3 (13), and is electrically connected to the aluminum base portion 2 via the solder solid body 7A. .
The member 21 to be joined may be a solderable metal member or a member provided with a solderable metal coating on the surface of a non-metal member.

Also, the member 21 itself can adopt the same configuration as that of the aluminum structure 1 (11) having the same configuration as in the first and second embodiments. In this case, the end 21a has the same configuration as the solder joint 3 (13).
Specifically, for example, the aluminum base portion 2 can be an electrode, and the bonded member 21 can be an aluminum wire. In this case, the end 21a may be formed with a solder joint similar to that in the first or second embodiment, for example, with nickel or the like.

A semiconductor device 30 shown in FIG. 8B is another example of an aluminum structure assembly.
The semiconductor device 30 includes an aluminum wiring substrate 32 provided with an aluminum structure 1 (11) constituting an electric circuit on an insulating substrate 31, and solder on each solder joint 3 (13) of the aluminum wiring substrate 32. The semiconductor element 33 (member to be joined) joined is provided via the solidified body 7A.
The semiconductor element 33 is provided with a connection electrode 33a at a position on the back surface facing the solder joint 3 (13). The connection electrode 33a and the solder joint 3 (13) are soldered to form an aluminum base. Electrical connection between the electrical circuit of the material part 2 and the semiconductor element 33 is established.
Examples of the semiconductor element 33 include various IC chips and solar cells. When the semiconductor element 33 is a solar battery cell, the semiconductor device 30 can be a solar battery module.

  The components described in the above embodiments and modifications can be implemented by being appropriately combined or deleted within the scope of the technical idea of the present invention.

Hereinafter, specific examples will be described together with comparative examples.
FIGS. 9A and 9B are a photographic image showing an example of the surface of an aluminum structure of an example corresponding to the second embodiment of the present invention, and a photographic image showing an example of the surface of a comparative example. .

Examples 1 to 4 and Comparative Examples 1 and 2 are examples in which, in the aluminum structure 11 having the configuration of the second embodiment, nickel was used for the metal particles 14 and the plating time was changed, It is a comparative example.
These manufacturing conditions and evaluation results described later are summarized in Table 1 below.

[Example 1]
The aluminum base part 2 made of pure aluminum foil (thickness 50 μm) was immersed in a sodium hydroxide solution, the surface was etched, and the oxide film 5 on the surface was removed (oxide film removing step).
Thereafter, the aluminum surface 2a other than the solder joint portion 13 is covered with a mask, and then immersed in an aqueous solution (plating solution) containing fluoride and nickel salt for 30 seconds to precipitate nickel particles (metal layer portion forming step). An aluminum structure 11 was manufactured.
When the layer thickness of the metal layer portion by the metal particles 14 of the solder joint portion 13 was measured with a fluorescent X-ray film thickness meter, the average layer thickness was measured to be 5 nm (see Table 1).
When the surface of the metal layer portion at this time is observed with an electron microscope, as shown in FIG. 9 (a), on the aluminum surface 2a (dark color portion), extremely fine particulate metal particles 14 (white portion). It was found that a large number of were dispersed and precipitated.
Eutectic solder (40% lead, 60% tin) was melted on the solder joint portion 13 using a soldering iron and soldered to a copper wire as a member to be joined.

[Examples 2 to 4]
Examples 2 to 4 are examples in which only the plating time of Example 1 was changed to 1 minute, 3 minutes, and 5 minutes in order.
In Examples 2 to 4, as shown in Table 1, the average layer thickness measured with a fluorescent X-ray film thickness meter increased as the plating time increased and was 9 nm, 70 nm, and 95 nm, respectively.
Copper wires were soldered to Examples 2 to 4 in the same manner as in Example 1.

[Comparative Examples 1 and 2]
Comparative Examples 1 and 2 are examples in which only the plating time of Example 1 was changed to 7 minutes and 10 minutes in order.
In Comparative Examples 1 and 2, as shown in Table 1, the average layer thickness measured with a fluorescent X-ray film thickness meter increased as the plating time increased and was 154 nm and 215 nm, respectively.
The copper wires were soldered to Comparative Examples 1 and 2 in the same manner as in Example 1.
As described above, as the plating time becomes longer, the particle size of the precipitated metal particles increases remarkably. As an example, a photographic image of the surface in the case of Comparative Example 2 is shown in FIG.
As can be seen from FIG. 9B, the shape of the metal particles exceeds 1 μm.

[Evaluation]
As evaluations of Examples 1 to 4 and Comparative Examples 1 and 2, the bonding state was evaluated by conducting conductivity evaluation using a resistance measuring instrument and pulling a copper wire.
In the electrical conductivity evaluation, it was confirmed that each example and each comparative example had electrical conductivity.
In the evaluation of the joining state, the fracture occurrence part when the copper wire was pulled was observed. As a result, as shown in Table 1, in Examples 1 to 4, although the aluminum foil around the solder joint portion was broken, the joint between the solder solidified body and the aluminum foil was not broken.
On the other hand, in Comparative Examples 1 and 2, the interface between the solder solidified body and the aluminum foil was broken.
For this reason, in Comparative Examples 1 and 2, the bonding strength between the solidified solder and the aluminum foil is low, whereas Examples 1 to 4 have good adhesion and bonding strength.

Table 1 shows the surface density of the metal obtained by calculation from the average film thickness measured with a fluorescent X-ray film thickness meter. According to this, in Examples 1 to 4, the surface density is 100 μg / cm ² or less, while in Comparative Examples 1 and ² , it exceeds 100 μg / cm ² .
Further, by observation with an electron microscope, in Examples 1 to 4, the height (layer thickness) of the metal particles 14 was 100 nm or less, whereas in Comparative Examples 1 and 2, it exceeded 100 nm. It was.
Thus, in Examples 1 to 4, since the cotton density and the layer thickness are appropriate, the solder solidified body 7A and the aluminum surface 2a are directly bonded, and as a result, good bonding strength is obtained. I understand.

Moreover, in order to investigate the joining strength fluctuation | variation with time, the aluminum structure 11 manufactured in Example 1 was left in the air for one week. As a result, the oxidation of the aluminum surface 2a proceeds and an oxide film is also formed on the nickel of the surface of the metal particles 14.
In this state, a copper wire was soldered in the same manner as described above.
Thereby, when conducting the same electrical conductivity evaluation as described above, it was confirmed to have electrical conductivity.
Moreover, when the copper wire was pulled, the aluminum foil was torn. From this, it was found that even when nickel particles were oxidized, adhesion was obtained.

[Example 5]
Example 5 is an example in which the metal material of the metal particles 14 is changed to copper.
That is, in the metal layer portion forming step of Example 1, the plating solution was immersed in an aqueous solution containing copper sulfate for 30 seconds to precipitate copper particles, thereby manufacturing the aluminum structure 11.
When measured with a fluorescent X-ray film thickness meter, the average layer thickness was measured to be 20 nm.
When the same evaluation as described above was performed, the conductivity was confirmed to be conductive. Moreover, in evaluation of a joining state, since aluminum foil was torn and destroyed like Example 1, even if the metal particle body 14 is formed with copper, the height (layer thickness) of the metal particle body 14 is appropriately set. As a result, it can be seen that the solder solidified body 7A and the aluminum surface 2a are directly bonded, and as a result, good bonding strength can be obtained.

DESCRIPTION OF SYMBOLS 1,11 Aluminum structure 2 Aluminum base part 2a Aluminum surface 3,13 Solder joint part 4 Metal thin film (metal layer part)
5 Oxide film 7 Solder melt 7A Solder solidified body 14, 14A Metal particle (metal layer part)
14a Projection 14b Contact 20 Assembly (Aluminum structure assembly)
21 Joined member 21a End 30 Semiconductor device (aluminum structure assembly, solar cell module)
32 Aluminum wiring board 33 Semiconductor element (solar cell)

Claims (11)

An aluminum structure having a solder joint for soldering on the surface of an aluminum base part made of aluminum alone or an aluminum alloy,
The solder joint is
Provided with a metal layer portion made of a metal other than aluminum capable of forming an alloy with solder on the surface of the aluminum base portion,
The layer thickness of the metal layer portion is
An aluminum structure characterized in that the metal layer portion is dissolved in solder at the time of soldering so that the solder can be penetrated in the layer thickness direction. The metal layer portion is
2. The aluminum structure according to claim 1, wherein the metal is a metal thin film having a layer thickness of 1 nm to 50 nm and covering a surface of the aluminum base portion. The metal layer portion is
The metal is dispersed in a layered region as metal particles having a particle shape or a lump shape with a height of 1 nm or more and 100 nm or less, and the surface density of the metal in the layered region is 1 μg / cm ² or more and 100 μg / cm ² or less. The aluminum structure according to claim 1, wherein The aluminum structure according to any one of claims 1 to 3, wherein the metal in the metal layer portion is a metal that is nobler than aluminum in an electrochemical column. A method for producing an aluminum structure having a solder joint for soldering on the surface of an aluminum base part made of aluminum alone or an aluminum alloy,
An oxide film removing step of immersing the aluminum substrate part in a chemical solution to remove the aluminum oxide film on the surface of the aluminum substrate part;
On the surface of the aluminum base part from which the aluminum oxide film has been removed, a metal other than aluminum capable of forming an alloy with solder is dissolved in the solder during soldering, so that the solder penetrates in the layer thickness direction. A metal layer part forming step of forming a metal layer part by adhering to a layer thickness;
The manufacturing method of the aluminum structure characterized by the above-mentioned. In the metal layer portion forming step,
The method for producing an aluminum structure according to claim 5, wherein the metal layer portion is formed by plating. In the metal layer portion forming step,
The method for producing an aluminum structure according to claim 6, wherein the plating solution used for the plating contains a halogen element. The aluminum structure according to any one of claims 1 to 4,
What is claimed is: 1. An aluminum structure assembly comprising: a member to be joined joined by soldering to the solder joint portion of the aluminum structure.   An aluminum wiring board comprising an electric circuit formed of the aluminum structure according to any one of claims 1 to 4. An aluminum wiring board according to claim 9,
A semiconductor element soldered to the solder joint of the aluminum wiring board;
A semiconductor device comprising: An aluminum wiring board according to claim 9,
A solar battery module comprising: a solar battery cell soldered to the solder joint portion of the aluminum wiring board.