JP2021109425A - Metal ceramic laminate - Google Patents

Abstract

To provide a metal ceramic laminate having improved bonding force between a metal film and a ceramic film.SOLUTION: A metal ceramic laminate has a base material, a ceramic film formed on the base material, and a metal film formed on the ceramic film. A turn-over part is formed at an interface between the ceramic film and the metal film, and the turn-over part has a length density of 0.2 μm/μm2 or more and 5.0 μm/μm2 or less.SELECTED DRAWING: Figure 2

Description

The present invention relates to a metal-ceramic laminate in which a metal film is formed on a ceramic film.

A ceramic laminate in which a ceramic film having excellent mechanical properties, reactivity resistance, heat resistance, insulation, heat dissipation, etc. is formed on a base material such as metal, ceramics, or resin is a wear-resistant member and corrosion-resistant. It is widely used for members, insulated heat-dissipating members, and the like. Examples of the ceramic material used for the ceramic film of such a ceramic laminate include aluminum oxide (Al ₂ O ₃ ), aluminum nitride (Al N _{), silicon nitride (Si 3 N 4} ), and zirconium oxide (ZrO ₂ ). Examples thereof include ceramic carbide (SiC), yttrium oxide (Y ₂ O ₃ ), silicon oxide (SiO ₂ ), and aluminum nitride (BN). On the other hand, depending on the application, a metal-ceramic laminate in which a metal film is further formed on the entire surface or a part of the ceramic film to impart the required metal properties may be required. For example, the conductor circuit pattern of the heat insulating member corresponds to this.

However, in these applications, the usage environment of metal-ceramic laminates is becoming more and more harsh, and under stress of various types and sizes during use, "base material and ceramic film" and "ceramic film" It is required that the "metal film" is firmly bonded (high bonding force) without peeling at each interface. However, depending on the manufacturing method, high-temperature heating exceeding 500 ° C. is required in the process of joining or forming each material, and residual thermal stress is generated due to the difference in thermal expansion between the materials, which reduces the joining strength. May be done. Therefore, it is preferable to form a ceramic film and a metal film without high-temperature heating in the manufacturing process to obtain a metal-ceramic joint in which no residual thermal stress is generated.

Regarding the formation of the ceramic film on the base material at room temperature (or low temperature), the ceramic film and the base material are relatively firmly bonded by the aerosol deposition method (also called the AD method), which is one of the ceramic film forming methods. At the same time, the ceramic film can be formed at room temperature. The aerosol deposition method is a technology that forms a dense ceramic film on a substrate at room temperature by mixing fine ceramic particles with a gas to make it into an aerosol and injecting it onto the substrate at high speed in a depressurized film formation chamber. be. The injected ceramic fine particles are deformed when they collide with the base material, so that chemical bonds can be formed between the fine particles / base material or between the new surfaces between the fine particles / fine particles, and further, the film can be densified. can do. In particular, between the fine particles / the base material, the fine particles scrape the surface of the base material and dig into the fine particles to form fine irregularities, and an anchor effect can also be obtained.

On the other hand, regarding the low temperature formation of the metal film on the ceramics, the metal film can be formed at a relatively low temperature by a plating method, a paste coating method, or the like. Further, since the above-mentioned aerosol deposition method can form a film on a metal material, it is also conceivable to form a metal film at room temperature by the aerosol deposition method. Several metal-ceramic laminates in which a metal film is formed on ceramics by these methods have been proposed (see Patent Documents 1 to 3).

Patent Document 1 describes a method of forming a metal film on an inorganic surface by performing electroless plating after alkali roughening an inorganic surface made of ceramics or the like. Further, Patent Document 1 describes that a metal film by electroless plating on an inorganic surface such as ceramics can be stably formed by the above method.

Patent Document 2 describes a circuit board in which an insulating substrate made of ceramics and a conductor layer are integrated via a copper plating layer. Further, in Patent Document 2, by interposing a copper plating layer between the insulating substrate and the conductor layer, the insulating substrate and the conductor pattern are firmly integrated even if the conductor layer does not contain a glass component. It is stated that can be realized. Further, Patent Document 2 describes that this circuit board is manufactured by forming a copper layer on an insulating substrate by a plating method, applying a conductor paste on the copper layer, drying and firing the circuit board.

Patent Document 3 describes a method of forming an electrode or a wiring pattern made of a metal thin film on a substrate such as alumina by using an aerosol deposition method. Further, Patent Document 3 describes that the process can be significantly reduced as compared with the paste printing method using a solution or a resin component.

Japanese Unexamined Patent Publication No. 61-063581 Japanese Patent No. 630709 Japanese Patent No. 5659495

When using the plating method, strong bonding is achieved unless the surface of the ceramic base material is etched in advance to form irregularities in order to develop an anchor bond between the plating film (layer) and the ceramic base material. Hard to get. In addition, even when etching is performed, the surface of the ceramics may be damaged and the strength may decrease, and basically the grain boundaries of the ceramics are etched, so the interface shape should be complicated. Has the problem of being difficult. On the other hand, when a metal material is formed by the aerosol deposition method, the material of the lower layer is often relatively less deformed than the metal particles, so that it is difficult for a new surface of the surface of the lower layer material to appear, and due to unevenness. It becomes difficult to obtain the anchor effect. Therefore, when the metal film is formed by the aerosol deposition method, there is a problem that it is difficult to obtain a higher bonding force than when the ceramic film is formed by the same method. However, in any of Patent Documents 1 to 3, sufficient studies have not always been made from these viewpoints.

The present invention has been made in view of the above problems, and an object of the present invention is to form a metal film on a ceramic film, and to laminate a metal ceramic having an improved bonding force between the metal film and the ceramic film. To provide the body.

The present invention that achieves the above object is as follows.
(1) A base material, a ceramic film formed on the base material, and a metal film formed on the ceramic film are included, and a burr portion is formed at an interface between the ceramic film and the metal film. A metal-ceramic laminate having a barb length density of 0.2 μm / μm ² or more and 5.0 μm / μm ^{2 or less.}
(2) The metal according to (1) above, wherein the ceramic film contains a metal dispersion phase, and the maximum depth of existence of the metal dispersion phase is 1/3 or less of the thickness of the ceramic film. Ceramic laminate.
(3) The metal-ceramic laminate according to (1) or (2) above, wherein the porosity in the region near the ceramic film side of the interface is 3% or less.
(4) The metal-ceramic laminate according to any one of (1) to (3) above, wherein the ceramic film contains silicon nitride.
(5) The metal-ceramic laminate according to any one of (1) to (4) above, wherein the metal film contains copper.
(6) The ceramic laminate according to any one of (1) to (5) above, wherein the base material is a metal material.
(7) An insulated heat-dissipating member, characterized in that it is composed of the metal-ceramic laminate according to any one of (1) to (6) above.

According to the present invention, in a metal-ceramic laminate in which a metal film is formed on a ceramic film, ^{a length density of 0.2 μm / μm 2} or more and 5.0 μm / μm ² or less is provided at the interface between the ceramic film and the metal film. Since the metal film and the ceramic film can be intricately meshed with each other by forming the burr portion having the above, it is possible to realize a metal-ceramic laminate having an excellent bonding force between the metal film and the ceramic film. can.

It is the schematic which shows an example of the cross section in the film thickness direction of the metal ceramics laminated body which concerns on embodiment of this invention. It is the schematic which shows an example of the cross section in the film thickness direction of the interface part of a ceramic film and a metal film. It is the schematic which shows an example of the cross section in the film thickness direction of the interface part of a ceramic film and a metal film. It is the schematic which shows an example of the cross section in the film thickness direction of the interface part of a ceramic film and a metal film. It is the schematic which shows an example of the aerosol deposition apparatus used in the manufacturing method of the metal ceramics laminate which concerns on embodiment of this invention.

<Metal ceramic laminate>
The metal-ceramic laminate according to the embodiment of the present invention includes a base material, a ceramic film formed on the base material, and a metal film formed on the ceramic film, and is an interface between the ceramic film and the metal film. A return portion is formed, and the length density of the return portion is 0.2 μm / μm ² or more and 5.0 μm / μm ² or less.

As described above, techniques for forming a metal film on a ceramic film at a low temperature include, for example, a plating method, a paste coating method, and an aerosol deposition method. However, regardless of which technique is applied, it is difficult to obtain a sufficient anchor effect by forming irregularities at the interface by the conventional method, or an additional step such as etching is required to obtain such an anchor effect. There is a problem that there is a problem, and further, an additional process such as etching may damage the surface of the ceramics and reduce the strength. Therefore, it is generally difficult to obtain a metal-ceramic laminate in which a ceramic film and a metal film are surely laminated with a high bonding force without adverse effects such as a decrease in strength.

Therefore, in the metal-ceramic laminate in which the metal film is formed on the ceramic film, the present inventors have a predetermined length density, specifically 0.2 μm / μm, at the interface between the ceramic film and the metal film. ^{By providing a form with a length density of 2} or more and 5.0 μm / μm 2 or less so that a part of the metal film is buried in the surface of the ceramic film, the metal film and the ceramic film are intricately meshed with each other. Therefore, it has been found that a metal-ceramic laminate having an excellent bonding force between the metal film and the ceramic film can be realized.

Hereinafter, the metal-ceramic laminate according to the embodiment of the present invention will be described in more detail with reference to the drawings, but these explanations are intended merely as an example of a preferred embodiment of the present invention, and the present invention is intended. Is not intended to be limited to such particular embodiments.

FIG. 1 is a schematic view showing an example of a cross section of the metal-ceramic laminate according to the embodiment of the present invention in the film thickness direction. Referring to FIG. 1, the metal-ceramic laminate 1 is composed of a base material 2, a ceramic film 3 laminated on the base material 2, and a metal film 4 laminated on the ceramic film 3. The base material 2 can have any suitable shape and is not particularly limited, but in practice, the base material 2 is made of, for example, a member having a plate shape, a columnar shape, a cylindrical shape, or the like. The ceramic film 3 is formed on the entire surface or a part of the base material 2. Further, the metal film 4 is formed on the entire surface or a part of the ceramic film 3. The interface 5 between the base material 2 and the ceramic film 3 and the interface 6 between the ceramic film 3 and the metal film 4 appear on the cross section of the metal-ceramic laminate 1 in the film thickness direction.

FIG. 2 is a schematic view showing an example of a cross section in the film thickness direction of the interface portion between the ceramic film and the metal film. As shown in FIG. 2, the interface 6 between the ceramic film 3 and the metal film 4 forms a barb portion 6a having a predetermined length density, which will be described in detail later, and one of the metal film 4 is formed on the barb portion 6a. Since the metal film 4 and the ceramic film 3 are intricately meshed with each other by filling the portion, it is possible to create an excellent bonding force between the metal film 4 and the ceramic film 3. Here, in the present invention, the barb portion refers to the portion shown by the thick line 6a in FIG. 2, and more specifically, among the interface 6 which is a continuous curve formed by the metal film 4 and the ceramic film 3. It refers to the portion of the interface 6 in which one or more interfaces exist in the film thickness direction excluding the interface on the most metal film side. Hereinafter, each configuration of the metal-ceramic laminate according to the embodiment of the present invention will be described in more detail.

[Base material]
The base material according to the embodiment of the present invention may be any suitable material, and is not particularly limited, but is preferably a metal material, for example. By using a metal material as the base material, it is possible to obtain a metal ceramics laminate having excellent characteristics of each of the ceramic film and the metal base material, which have significantly different physical properties from each other. Such a metal material is not particularly limited, but for example, copper (Cu), aluminum (Al), iron (Fe), nickel (Ni), titanium (Ti), molybdenum (Mo), zirconium (Zr), and the like. Titanium (W), silver (Ag), chromium (Cr), manganese (Mn), zinc (Zn), yttrium (Y), niobium (Nb), cobalt (Co), platinum (Pt), vanadium (V), It may be at least one selected from the group consisting of palladium (Pd) and gold (Au), or may be an alloy containing at least one of these elements as a main component. Alternatively, the metal material may be a composite material in which a material other than the metal such as ceramics is contained in at least one of these elements or in an alloy containing at least one of these elements as a main component. good. In the present invention, the main body means that the target material is contained in an amount of 50% by mass or more based on the total mass.

[Ceramics film]
The ceramic film formed on the above-mentioned base material has an improved bonding force as long as a burr portion ^{of 0.2 μm / μm 2} or more and 5.0 μm / μm ^{2 or less is formed at the interface with the metal film.} Since it can be provided, the type of ceramic material constituting the ceramic film is not particularly limited. Therefore, the ceramic film may be any ceramic material, and is not particularly limited, and is, for example, aluminum oxide, aluminum nitride, silicon nitride, zirconium oxide, silica carbide, yttrium oxide, silicon oxide, and boron nitride. It may contain at least one selected from the group consisting of, or may be at least one selected from the above group, or may be a composite ceramic mainly composed of at least one of these ceramics. .. Among these, since silicon nitride has excellent mechanical properties and relatively high thermal conductivity, the ceramic film should contain silicon nitride or be silicon nitride from this viewpoint. Is desirable.

[Metal film]
Similarly, the metal film may contain any suitable metal material and is not particularly limited, but is preferably containing or being copper, for example, copper (Cu) having high thermal and electrical conductivity. .. Further, since copper has high stability in a powder state among metal materials, it also has an advantage of excellent handleability when a metal powder is used when forming a metal film (for example, an aerosol deposition method).

[Length density (M) of the barb: 0.2 μm / μm ² or more and 5.0 μm / μm ² or less]
In the metal-ceramic laminate according to the embodiment of the present invention, a barb is formed at the interface between the ceramic film and the metal film, and the length density of the barb is 0.2 μm / μm ² or more and 5.0 μm / μm ^2. It is as follows. By setting the length density of the barb portion to 0.2 μm / μm ² or more and 5.0 μm / μm ² or less, the metal film and the ceramic film can be intricately meshed with each other. It is possible to develop excellent bonding force. The length density of the barb is preferably 1.0 μm / μm ² or more, and more preferably 3.0 μm / μm ² or more. By increasing the length density of the barb portion, the metal film and the ceramic film can be more complicatedly meshed with each other, so that a more excellent bonding force can be exhibited between the metal film and the ceramic film.

On the other hand, when the length density of ^{the barb is less than 0.2 μm / μm 2} , the amount of the barb is small and the metal film and the ceramic film cannot sufficiently mesh with each other, so that the bonding force is reduced. .. For example, in the case where the interface between the ceramic film and the metal film is simply uneven in the film thickness direction, the length density of the barb portion is 0.0 μm / μm ² , so the bonding force is low. As described above, the length density of the barb is basically desirable as it is larger, but if it is too large, the amount of the ceramic material that enters the upper part or the inside (7 or 8 in FIG. 2) of the barb in the ceramic film is extremely large. Since the amount is reduced, the ceramic film is easily broken, resulting in a decrease in bonding force. Therefore, the length density of the barb portion may be 5.0 μm / μm ² or less, and ^{may be 4.5 μm / μm 2} or less.

[Measurement of length density (M) of barb]
In the present invention, the length density of the barb portion means the total length of the barb portion included in the unit area, and is represented by the following (Equation 1).
_{M = (I 1 + I 2} + ··· + I n + ··· + I N) / A ( Formula 1)
Referring to FIG. 2, where, M represents the length density (μm / μm ²⁾ of the barb portion 6a, N represents the number of barbs 6a in the interface region 6b, I _n the interface region The nth barb (an integer of 1 ≦ n ≦ N) in 6b represents the length (μm) of the barb portion 6a, and A represents the area (μm ² ) of the interface region 6b. The interface region 6b is a rectangular region surrounding the interface 6, that is, a rectangular region in which the maximum height difference of the interface 6 is vertical and an arbitrary length of 10 μm or more in the in-plane (horizontal) direction is horizontal. be.

Specifically, the length density M of the barb portion is determined as follows. First, an SEM image of a cross section in the film thickness direction in which the interface between the ceramic film and the metal film is clearly photographed is prepared. The SEM image used has a length of 0.02 μm or less per pixel, a field of view length of 10 μm or more in the in-plane direction, and a field of view length in the film thickness direction that fits the interface between the ceramic film and the metal film in the field of view. It needs to be above. When the visual field length in the in-plane direction and the visual field length in the film thickness direction cannot be secured by one SEM image, a plurality of SEM images are connected to secure each visual field length. Next, in this SEM image, the interface between the ceramic film and the metal film is traced as a continuous curve by image analysis software or the like to determine the interface. A rectangular interface region described above is drawn with respect to the determined interface, and the area A is measured. Then, among the determined interface, extracting a portion corresponding to the barbs described above, each of length I ₁ of the N barbs, I _2, to measure · · · I _N. Finally, the length density M of the barb portion is calculated from the above equation (1).

[Maximum existence depth (H) of the metal dispersion phase: 1/3 or less of the thickness (t) of the ceramic film]
FIG. 3 is a schematic view showing an example of a cross section in the film thickness direction of the interface portion between the ceramic film and the metal film. In the production of the metal-ceramic laminate 1, in order to form a burr portion 6a at the interface 6 between the ceramic film 3 and the metal film 4 to improve the bonding force, the metal dispersion phase 3a is provided on the ceramic film 3 side depending on the production conditions. It may be unavoidably mixed. When the amount of the metal dispersion phase 3a mixed is large, that is, when the metal dispersion phase 3a is mixed deep in the ceramic film 3, the metal dispersion phase 3a becomes a starting point of fracture in the ceramic film 3 and becomes a ceramic. The mechanical properties and insulating properties inherent in the film 3 may be deteriorated.

In the present invention, the metal-dispersed phase refers to a metal phase having a ^{phase area of 0.01 μm 2} or more that is isolated and dispersed from the interface between the ceramic film and the metal film to the ceramic film side. Since the metal-dispersed phase having a phase area of less than 0.01 μm ² has a small phase area, it is unlikely to cause deterioration of the mechanical properties and insulating properties inherent in the ceramic film, and its influence can be ignored. In the metal-ceramic laminate according to the embodiment of the present invention, the maximum depth of existence of the metal dispersion phase is 1/3 of the thickness of the ceramic film in order to ensure that the original mechanical properties and insulating properties of the ceramic film are exhibited. It is desirable that it is as follows. The maximum existing depth of the metal dispersion phase is preferably 1/5 or less of the thickness of the ceramic film, and more preferably 1/10 or less of the thickness of the ceramic film. On the other hand, when the maximum depth of existence of the metal dispersion phase is more than 1/3 of the thickness of the ceramic film, the mechanical properties and insulating properties inherent in the ceramic film are deteriorated as described above, and the bonding force is increased. There is a risk that it will be lowered or that the insulation will be easily broken.

[Measurement of maximum existing depth (H) of metal dispersion phase and thickness (t) of ceramic film]
In the present invention, the maximum existence depth of the metal dispersed phase is explained with reference to FIG. 3, as shown by H in FIG. 3, the maximum height of the interface 6 between the ceramic film 3 and the metal film 4 and a plurality of depths. It refers to the difference in height between the metal dispersion phase 3a and the metal dispersion phase 3a existing in the deepest part of the ceramic film 3. The thickness of the ceramic film is the difference between the maximum height of the interface 6 between the ceramic film 3 and the metal film 4 and the minimum height of the interface 5 between the ceramic film 3 and the base material 2, as shown as t in FIG. It means.

Specifically, the maximum existence depth of the metal dispersion phase and the thickness of the ceramic film are determined as follows. First, an SEM image of a cross section in the film thickness direction is prepared in which the interface between the ceramic film and the metal film and the interface between the ceramic film and the base material are clearly photographed. The SEM image used has a length per pixel of 0.02 μm or less, a field length in the in-plane direction of 10 μm or more, and a field length in the film thickness direction from the interface between the ceramic film and the metal film to the ceramic film and the base material. It must be longer than the length that allows the interface to be within the field of view. When the visual field length in the in-plane direction and the visual field length in the film thickness direction cannot be secured by one SEM image, a plurality of SEM images are connected to secure each visual field length. Next, in this SEM image, ^{the metal dispersion phase having a phase area of 0.01 μm 2} or more described above is detected by image analysis software or the like to measure the maximum existence depth of the metal dispersion phase, and the ceramic film is formed. Measure the thickness.

[Porosity (ρ): 3% or less in the region near the ceramic film side at the interface between the ceramic film and the metal film]
In the metal-ceramic laminate according to the embodiment of the present invention, it is desirable that the porosity in the region near the ceramic film side at the interface between the ceramic film and the metal film is 3% or less. FIG. 4 is a schematic view showing an example of a cross section in the film thickness direction of the interface portion between the ceramic film and the metal film. In the production of the metal-ceramic laminate 1, as shown in FIG. 4, pores 3c may be generated in the region 3b near the ceramic film side of the interface 6 between the ceramic film 3 and the metal film 4, depending on the production conditions. .. If the amount of pores 3c in the vicinity region 3b increases, it may become a starting point of fracture in the ceramic film 3 and reduce the strength of the ceramic film 3. Here, in the present invention, the region near the ceramic film side of the interface between the ceramic film and the metal film means a portion shown as an area B in FIG. 4, and more specifically, from the interface 6 and the interface 6. It refers to a region in the ceramic film 3 surrounded by a line drawn in the in-plane direction at a depth of 1/3 of the thickness t of the ceramic film 3. The line segment drawn in the in-plane direction has an arbitrary length of 10 μm or more. By setting the porosity in the vicinity region to 3% or less, the pores that are the starting points of fracture in the ceramic film 3 in the vicinity region can be reduced and the strength thereof can be improved. Therefore, the metal film 4 and the ceramic film 3 can be improved. The bonding strength of the ceramics can be further enhanced.

Further, in the present invention, the pores refer to pores having ^{a pore area of 0.0004 μm 2 or more.} Since the pore area of ^{less than 0.0004 μm 2} is small, it is unlikely to be the starting point of fracture in the ceramic film, and its influence can be ignored. The porosity is preferably 2% or less, more preferably 1% or less. By making the porosity smaller than 3%, the pores that are the starting points of fracture in the ceramic film can be further reduced and the strength can be further improved, so that the bonding force between the metal film and the ceramic film can be further enhanced. Can be done. On the other hand, when the porosity exceeds 3%, the pores that are the starting points of fracture increase in the ceramic film, so that the ceramic film in the region near the ceramic film side at the interface between the ceramic film and the metal film is easily destroyed, and as a result, the ceramic film is easily destroyed. , There is a risk that the bonding strength between the metal film and the ceramic film will decrease.

[Measurement of porosity (ρ) in the region near the ceramic film side at the interface between the ceramic film and the metal film]
The porosity in the region near the ceramic film side at the interface between the ceramic film and the metal film is represented by the following (Equation 2).
ρ = ((P ₁ + P ₂ + ... + P _k + ... + _PK ) / B) x 100 (Equation 2)
Explaining with reference to FIG. 4, in the equation, ρ represents the porosity (%) in the ceramic film side near region 3b of the interface 6 between the ceramic film 3 and the metal film 4, and K represents the porosity 3c in the near region 3b. It represents the number of, P _k is the area of the pores 3c of the k-th in the neighborhood region 3b (integer of 1 ≦ k ≦ K) (μm 2) , B stands area of the neighboring region 3b (μm ²⁾ Represents.

Specifically, the porosity ρ in the region near the ceramic film side at the interface between the ceramic film and the metal film is determined as follows. First, an SEM image of a cross section in the film thickness direction is prepared in which the interface between the ceramic film and the metal film and the interface between the ceramic film and the base material are clearly photographed. The SEM image used has a length per pixel of 0.02 μm or less, a field length in the in-plane direction of 10 μm or more, and a field length in the film thickness direction from the interface between the ceramic film and the metal film to the ceramic film and the base material. It must be longer than the length that allows up to the interface 5 to be within the field of view. When the visual field length in the in-plane direction and the visual field length in the film thickness direction cannot be secured by one SEM image, a plurality of SEM images are connected to secure each visual field length. Next, in this SEM image, the interface between the ceramic film and the metal film is traced as a continuous curve by image analysis software or the like to determine the interface. Using the determined interface, the area 3b near the ceramic film side of the interface between the ceramic film and the metal film described above is extracted, and the area B is measured. Next, pores having a pore area of 0.0004 μm ² or more in the vicinity region 3b are extracted, and the respective areas P ₁ , P ₂ , ... _PK are measured. Finally, from the above equation (2), the porosity ρ in the region near the ceramic film side at the interface between the ceramic film and the metal film is calculated.

[Manufacturing method of metal-ceramic laminate]
Next, a preferable manufacturing method of the metal-ceramic laminate according to the embodiment of the present invention will be described. The following description is intended to exemplify a characteristic method for producing the metal-ceramic laminate according to the embodiment of the present invention, and the metal-ceramic laminate is produced by a production method as described below. It is not intended to be limited to what is manufactured.

The method for forming the ceramic film on the substrate is not particularly limited to the PVD method, CVD method, thermal spraying method, cold spray method, sol-gel method, etc., but for example, the ceramic fine particles mixed with gas and aerosolized are depressurized. The aerosol deposition method, in which a ceramic film is formed by high-speed spraying onto a substrate in a film-forming chamber, is suitable in that a dense ceramic film can be formed at room temperature. Further, when the ceramic film is formed, the final layer is formed by using the ceramic powder containing the same kind of metal powder as the metal film, so that the surface of the ceramic film is filled with the metal phase. When a metal film was formed on the metal film, the metal film was bonded to the same type of metal phase embedded in the ceramic film, and the interface between the ceramic film and the metal film as shown in FIG. 2 had a complicated shape. A metal-ceramic laminate according to an embodiment of the present invention can be produced.

The method for forming the metal film on the ceramic film is not particularly limited, such as a plating method, a paste coating method, a thermal spraying method, a cold spray method, and a gas deposition method. The method is desirable in that a dense metal film can be formed at room temperature. Hereinafter, a method for manufacturing a metal-ceramic laminate will be described by taking the aerosol deposition method as an example.

FIG. 5 is a schematic view showing an example of an aerosol deposition device used in the method for manufacturing a metal-ceramic laminate according to an embodiment of the present invention. The metal-ceramic laminate 1 is manufactured by using the aerosol deposition apparatus 11 illustrated in FIG. The aerosol deposition device 11 of FIG. 5 includes an aerosolization container 12, a film forming chamber 13, an aerosol transfer pipe 14, a vacuum pump 15, and a gas supply system 16. The aerosolization container 12 and the film forming chamber 13 are connected by an aerosol transfer pipe 14. The vacuum pump 15 is connected to the film forming chamber 13 and decompresses the inside of the film forming chamber 13. The gas supply system 16 and the aerosolization container 12 are connected by the adjusting gas pipe 18 and the hoisting gas pipe 19.

The aerosolation container 12 contains the raw material powder 17 of ceramics or metal inside the container, and the raw material powder 17 is charged with nitrogen (N ₂ ) gas, helium (He) gas, and argon (Ar) from the hoisting gas pipe 19. A film-forming gas such as gas, oxygen (O ₂ ) gas, or air is supplied as a hoisting gas, and the film-forming gas is also supplied as a adjusting gas from the adjusting gas pipe 18 to the internal space of the aerosolization container 12. The aerosolization container 12 is provided with a vibration mechanism (not shown) for stirring the raw material powder 17 and a heating mechanism (not shown) for drying the raw material powder 17. Further, depending on the purpose, a mechanism (not shown) for continuously supplying the raw material powder 17 to the aerosolization container 12 while scraping it little by little with a rotating circular brush may be provided in the middle of the hoisting gas pipe 19. be. In this case, the raw material powder 17 is not contained in the aerosolization container 12 before the film formation, and the raw material powder is continuously supplied after the film formation starts.

Inside the film forming chamber 13, a stage 20 is provided so that the base material fixing surface faces the nozzle port of the aerosol transfer tube 14. The base material 2 is fixed to the base material fixing surface of the stage 20. The stage 20 is provided with a horizontal drive mechanism 21 for repeatedly spraying the aerosol onto the surface of the base material 2 or the ceramic film 3 by changing the position where the aerosol hits the base material 2 or the ceramic film 3 by moving the stage 20. ..

In the aerosol deposition device 11 having the above configuration, the deposited gas is supplied from the gas supply system 16 into the aerosolizing container 12 through the hoisting gas pipe 19, and the aerosol containing the raw material powder fine particles is supplied to the aerosolizing container 12 Generate in. At this time, the aerosol deposition device 11 supplies the film-forming gas into the aerosolizing container 12 through the adjusting gas pipe 18, and the aerosolized container is supplied by the forming gas supplied from the adjusting gas pipe 18 and the hoisting gas pipe 19. The aerosol in 12 is supplied to the film forming chamber 13 through the aerosol transfer pipe 14.

In the film forming chamber 13 decompressed by the vacuum pump 15, the aerosol is injected from the nozzle port of the aerosol transfer pipe 14 toward the base material 2 or the ceramic film 3 fixed to the stage 20. At this time, the aerosol deposition device 11 reciprocates the stage 20 in the horizontal direction (in the direction of the arrow in FIG. 5) by the horizontal drive mechanism 21, and uses the aerosol injected from the nozzle port of the aerosol transfer pipe 14 as the base material. 2 or the surface of the ceramic film 3 is repeatedly sprayed.

Hereinafter, a method for manufacturing a metal-ceramic laminate using the aerosol deposition method (AD method) will be described in more detail. For example, the metal-ceramic laminate according to the embodiment of the present invention having the characteristics described above may be used.
Step of forming a ceramic film on a substrate by an aerosol deposition method using ceramic powder (step 1),
A step (step 2) of forming a form in which the metal phase is dispersed and buried on the surface of the ceramic film by an aerosol deposition method using a mixed powder obtained by blending the metal powder with the ceramic powder, and on the obtained ceramic film. A step of forming a metal film by an aerosol deposition method using the metal powder (step 3).
It can be manufactured by a method characterized by containing. According to the above manufacturing method, a complicated shape as shown in FIG. 2 can be easily formed at the interface between the ceramic film and the metal film. Hereinafter, each step of this manufacturing method will be described in detail.

[Step 1: Ceramic film forming step]
Optimal film formation conditions exist in the ceramic film forming step (step 1) by the aerosol deposition method. Among them, the effect of the particle size of the ceramic raw material powder is particularly large, and the film forming phenomenon cannot occur unless the film is formed using the raw material powder having the optimum particle size. For example, if the particle size is too large, the particles are not deformed and the base material is scraped off like a blast, so that a film is not formed. If the particle size is too small, the particles follow the film-forming gas, so that the particles do not collide with the base material and the film is not formed as well. Generally, the range of the particle size of the ceramic powder that can be formed by the aerosol deposition method is about 0.1 to 10 μm, but this range is, for example, about 0.1 to 1.0 μm depending on the material system. In many cases, it is further squeezed. The particle size refers to the median diameter (particle size when the integrated volume reaches 50%) of the final ceramic raw material powder injected as an aerosol, and the same applies thereafter. On the other hand, regarding the film formation of metal powder, if the particle size range is about 0.1 to 10 μm, it is possible to form a film in a wide particle size range without further narrowing the range according to the material system unlike ceramic powder. There are many.

For example, when a ceramic film is formed on a base material containing or composed of a metal material by the aerosol deposition method, the injected ceramic particles are made of a metal having a significantly small relative hardness. Since unevenness that exerts an anchor effect is formed at the interface between the base material and the ceramic film by digging into the base material, there is an advantage that a high bonding force can be easily obtained between the metal base material and the ceramic film.

[Step 2: Interface adjustment step]
Further attention is required for the step (step 2) of embedding the metal dispersion phase on the surface of the ceramic film formed in step 1, as described below. In the aerosol deposition method, easily deformable metal particles are more easily formed into a film than hard-to-deform ceramic particles, so that a coarse metal phase may be mixed in the ceramic film. Therefore, when blending the metal powder with the ceramic powder, it is necessary to use a metal powder having a particle size (median diameter) of 2 times or less, preferably 1 time or less the particle size of the ceramic powder. That is, it is necessary to select a metal powder having a wide particle size range that can be formed into a film according to the particle size of the ceramic powder. Further, for the same reason as described above, when the metal powder is blended with the ceramic powder, the ratio of the metal powder in the blended raw material powder needs to be kept as small as about 1 to 30 vol%, although it depends on the material system. .. By appropriately controlling the particle size (median diameter) of the metal powder and the ratio of the metal powder, a barb is formed at the interface between the ceramic film and the metal film, and the length density M of the barb is 0.2 μm / m. A ^{metal-ceramic laminate having a thickness of μm 2} or more and 5.0 μm / μm ² or less can be reliably obtained.

For example, in order to make the maximum existence depth H of the metal dispersion phase 1/3 or less of the thickness of the ceramic film, the number of laminations and the amount of powder injection may be reduced in step 2 with respect to step 1. After 2, the surface of the ceramic film may be polished. Especially in the case of polishing, it is more desirable in that metal particles and ceramic particles weakly adhered to the film surface can be removed.

Since metal particles are easily formed into a film, if a film is formed in a state where the metal particles are aggregated in an aerosol, the metal particles are formed into a film without being densified, and pores are formed in the ceramic film formed in step 2. It may cause it. Therefore, in order to reduce the porosity ρ in the region near the ceramic film side of the interface between the ceramic film and the metal film to 3% or less, the raw material powder (mixed powder) is prepared by a method in which the ceramic particles and the metal particles are surely mixed with each other. It is desirable that the mixture is blended and sprayed as an aerosol while maintaining a mixed state. Examples of the method for blending the raw material powder include ball mills and bead mills, which are general powder mixing methods. However, in these methods, the energy applied at the time of mixing may be too large, and the metal particles may be significantly plastically deformed. , Metal particles may stick to each other. For this reason, it is desirable to reduce the applied energy or keep the mixture in a spatula or mortar. Further, when the aerosol deposition device is used for film formation, if a mechanism is used to continuously supply the powder to the aerosolization container while scraping the powder with a rotating brush during the film formation, the ceramic particles and metal particles in the raw material powder are more likely to be formed. It is preferable in that it is continuously supplied to the aerosolized container in a mixed state.

When the ceramic film is made of silicon nitride, it is relatively difficult to form a film by the aerosol deposition method. Therefore, when the metal powder is blended with the ceramic (silicon nitride) powder in step 2, It is desirable that the ratio of the metal powder in the compounding raw material powder is further reduced to about 1 to 20 vol%. As a result, a barb is formed at the interface between the ceramic (silicon nitride) film and the metal film, and the length density M of the barb is 0.2 μm / μm ² or more and 5.0 μm / μm ² or less. You can definitely get the body.

[Step 3: Metal film forming step]
Finally, in step 3, a metal film of the same type as the metal powder obtained by blending the raw material powder into the mixed powder in step 2 is used alone to form a metal film by the aerosol deposition method, whereby the ceramic film and the metal film are formed. It is possible to produce a metal-ceramic laminate having an interface having a complicated shape as shown in FIG. As described above, the metal powder used in step 3 is the same type of metal powder as the metal powder blended in the mixed powder in step 2. Therefore, the particle size (median diameter) of the metal powder is generally about 0.1 to 10 μm, as described in connection with steps 1 and 2, and is preferably used in step 1. The particle size of the ceramic powder is 2 times or less or 1 times or less.

The metal-ceramic laminate according to the embodiment of the present invention can be used in any suitable application, and is not particularly limited. However, since the ceramic film and the metal film are firmly bonded to each other, insulation and heat dissipation especially for semiconductor modules It can be effectively used as a member. The heat-insulating heat-dissipating member is a member that insulates electricity and releases heat in the semiconductor module. When the present metal-ceramic laminate is used as the insulating heat-dissipating member, for example, the ceramic film can serve as an insulating layer, the metal film can serve as a circuit layer, and the base material can serve as a base plate or a heat sink. The thickness of the ceramic film can be arbitrarily adjusted so that the required insulation (dielectric breakdown voltage) can be obtained according to the application of the module, but the dielectric breakdown voltage is preferably 0.1 kV or more, more preferably 0.1 kV or more. It is desirable to adjust the thickness of the ceramic film so that the value is 0.5 kV or more, more preferably 1 kV or more.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

In the following examples, the metal-ceramic laminate was produced under various conditions according to the above-mentioned method for producing the ceramic laminate, and the bondability between the metal film and the ceramic film was investigated.

[Step 1]
First, a ceramic film was formed on the substrate by using an aerosol deposition apparatus as shown in FIG. An oxygen-free copper base material having a particle size of 40 × 40 × 5 mm ³ was used as the base material, and a silicon nitride powder having a particle size of 0.8 μm was used as the raw material powder. Nitrogen gas was used as the hoisting gas and the adjusting gas, and the total of the hoisting gas flow rate and the adjusting gas flow rate was set to 24 L / min. The nozzle opening size at the tip of the aerosol transfer tube is 15 x 0.3 mm ² , the angle between the normal of the base material and the nozzle is 30 °, and the horizontal drive program of the stage on which the base material is fixed is 40 x 40 mm ² base material. The ceramic film was set to be formed on the entire surface with a thickness of about 10 μm.

[Step 2]
Next, a film was formed on the ceramic film using the same aerosol deposition device as in step 1, and a form in which the metal phase was dispersed and buried on the surface of the ceramic film was formed. As the raw material powder, a powder obtained by blending the ceramic powder used in the step 1 with the copper powder having a particle diameter of 1.5 μm or 0.4 μm used in the step 3 described later in a predetermined volume ratio with a spatula or a mortar was used. For compounding with a spatula and a mortar, the ceramic powder is added to the copper powder having a small volume ratio in about 10 times, and mixed at a speed of about 20 rotations in 10 seconds for a total of about 20 minutes. Was done by. For the powder supply to the aerosolization container, a general method of charging the entire amount before film formation was basically used, but a method of continuously charging a part with a rotating brush was adopted. Nitrogen gas was used as the hoisting gas and the adjusting gas, and the total of the hoisting gas flow rate and the adjusting gas flow rate was set to 24 L / min. The nozzle opening size at the tip of the aerosol transfer tube is 15 x 0.3 mm ² , the angle between the normal of the base material (or ceramic film) and the nozzle is 30 °, and the horizontal drive program of the stage on which the base material is fixed is 40 x. An additional ceramic film having a thickness of about 5 to 7 μm was set to be formed on the entire surface of the already formed ceramic film of 40 mm ^2. After the film formation, the maximum depth of existence of the metal dispersion phase was adjusted by polishing the surface of the ceramic film.

[Step 3]
Finally, using the same aerosol deposition apparatus as in Steps 1 and 2, a metal film was formed on the ceramic film in which the metal phase was dispersed and buried on the surface. As the raw material powder, a copper powder having the same particle size as that used in step 2 (that is, 1.5 μm or 0.4 μm in both step 2 and step 3) was used. Nitrogen gas was used as the hoisting gas and the adjusting gas, and the total of the hoisting gas flow rate and the adjusting gas flow rate was set to 24 L / min. The nozzle opening size at the tip of the aerosol transfer tube is 15 x 0.3 mm ² , the angle between the normal of the base material (or ceramic film) and the nozzle is 30 °, and the horizontal drive program of the stage on which the base material is fixed is 40 x. The metal film was set to be formed with a thickness of about 100 μm on the entire surface of the already formed ceramic film of 40 mm ^2. Note that before the deposition, by depositing the paste the masking tape having a 5 × plurality of openings of 5 mm ² to 40 × 40 mm ² of the ceramic membrane surface, 5 × 5 mm ^2, a thickness of about 100μm A form capable of evaluating the joint strength (described later) in which a plurality of metal films of No. 1 are formed on the ceramic film.

[Measurement of each characteristic of metal-ceramic laminate]
In each of the manufactured metal-ceramic laminates, the length density M of the barb, the maximum depth H of the metal dispersion phase, and the porosity ρ in the region near the ceramic film side of the interface between the ceramic film and the metal film are determined by the above [return]. Measurement of the length density (M) of the part], [Measurement of the maximum existence depth (H) of the metal dispersion phase and the thickness (t) of the ceramic film] and [Near the ceramic film side of the interface between the ceramic film and the metal film] Measurement of Porosity (ρ) in Region] The measurement was performed according to the method described in the section. The results are as shown in Table 1.

For the SEM observation sample used in the above measurement, each metal ceramic laminate was cut in the film thickness direction, the cross section in the film thickness direction that appeared was mirror-polished, and the cross section was 10,0000 by FE-SEM (ULTRA 55, Carl Zeiss). An SEM image was acquired by observing at a magnification of 2 times. In order to clarify the contrast between the phases, the SEM image was a reflected electron image. The acquired SEM image having a magnification of 10000 had a visual field length of 11.2 μm in the in-plane (horizontal) direction and a length of 0.0109 μm per pixel. When the target observation target did not fit in the film thickness direction, continuous images were acquired in the film thickness direction and they were connected. Image analysis software (Image-Pro Premier, Nippon Roper Co., Ltd.) was used for the analysis of each SEM image. In the measurement of each value by the image analysis software, the binarization process was performed in order to clarify the target object, and then the measurement of each value was performed. Regarding the maximum existing depth H of the metal dispersion phase and the thickness t of the ceramic film, the measurement points were visually determined by the binarized image, and the measurement points were measured by the length measurement function of the software.

[Evaluation of bondability]
The bondability of each of the manufactured metal-ceramic laminates was evaluated. Here, a universal bond tester (series 4000, Nordson Advanced Technology) was used to perform a shear strength test of a metal film formed ^{on a ceramic film with a size of 5 × 5 mm 2.} The test conditions were a tool width of 9 mm, a tool height of 10 μm, and a tool speed of 100 μm / s. The load when the metal film broke was measured at N = 6, and the average value of these was taken as the breaking load. Those with a breaking load of less than 3 kgf are evaluated as ×, those with a breaking load of 3 kgf or more and less than 6 kgf are evaluated as ○, those with a breaking load of 6 kgf or more and less than 9 kgf are evaluated as ○○, and those with a breaking load of 9 kgf or more are evaluated as ○○, ○○, The case of ○○○ was regarded as a pass. The results are as shown in Table 1.

As shown in Table 1, an example in which the interface between the ceramic film and the metal film forms a barb, and the length density M of the barb is 0.2 μm / μm ² or more and 5.0 μm / μm ² or less. In 3, 4 and 6 to 21, it was confirmed that the bondability between the metal film and the ceramic film was good. It is considered that this is because the metal film and the ceramic film could be intricately meshed with each other by setting the length density M of the barb portion to 0.2 μm / μm ² or more and 5.0 μm / μm ^{2 or less.}

Among Examples 3, 4 and 6 to 21, it was confirmed that Examples 6 to 9 and 14 to 21 were further excellent in bondability. This is because the length density M of the barb is set to 0.2 μm / μm ² or more and 5.0 μm / μm ² or less, and the maximum existence depth H of the metal dispersion phase is set to 1 of the thickness t of the ceramic film. It is considered that the original mechanical properties of the ceramic film could be exhibited by suppressing the influence of the mixed metal dispersion phase by reducing the size to 3/3 or less.

Among Examples 3, 4 and 6 to 21, it was confirmed that Examples 10 to 21 were further excellent in bondability. This is because the length density M of the barb is 0.2 μm / μm ² or more and 5.0 μm / μm ² or less, and the porosity ρ in the region near the ceramic film side at the interface between the ceramic film and the metal film is 3. It is considered that by reducing the value to% or less, the pores that are the starting points of fracture in the ceramic film 3 in the vicinity region can be reduced and the strength thereof can be improved.

For comparison, when the metal-ceramic laminate in which the length density M of the barb portion was ^{less than 0.2 μm / μm 2} was produced in Comparative Examples 1 and 2, the bondability was compared with Examples 3, 4 and 6 to 21. Was inferior. It is considered that this is because the amount of the burr portion is reduced and the metal film and the ceramic film cannot sufficiently mesh with each other. Further, when a metal-ceramic laminate having a barb length density M of ^{more than 5.0 μm / μm 2} was produced in Comparative Example 5, the bondability was found in Examples 3 and 4 and as in Comparative Examples 1 and 2. It was inferior to 6-21. It is considered that this is because the amount of the ceramic material entering the upper part or the inside of the barb portion in the ceramic film is extremely reduced, so that the ceramic film is easily broken. In Comparative Example 22, in which the metal film was only formed after etching the surface of the sintered body, the length density M of the barb portion was less than ^{0.2 μm / μm 2 as in Comparative Examples 1 and 2.} And the bondability was also inferior.

1 Metallic ceramic laminate 2 Base material 3 Ceramic film 3a Metal dispersion phase 3b Area near the interface between ceramic film and metal film on the ceramic film side 3c Pore 4 Metal film 5 Interface between base material and ceramic film 6 Interface between ceramic film and metal film 6a Backing part 6b Interface area 7 Backing part upper part 8 Inside the backing part H Maximum depth of metal dispersion phase t Ceramic film thickness 11 Aerosol deposition device 12 Aerosolization container 13 Film formation chamber 14 Aerosol transfer pipe 15 Vacuum pump 16 Gas supply system 17 Raw material powder 18 Adjusting gas piping 19 Winding gas piping 20 Stage 21 Horizontal drive mechanism

Claims (7)

A base material, a ceramic film formed on the base material, and a metal film formed on the ceramic film are included, and a barb portion is formed at an interface between the ceramic film and the metal film, and the barb portion of the barb portion is formed. A metal-ceramic laminate having a length density of 0.2 μm / μm ² or more and 5.0 μm / μm ^{2 or less.} The metal-ceramic laminate according to claim 1, wherein the ceramic film contains a metal-dispersed phase, and the maximum depth of existence of the metal-dispersed phase is 1/3 or less of the thickness of the ceramic film. The metal-ceramic laminate according to claim 1 or 2, wherein the porosity in the region near the ceramic film side of the interface is 3% or less. The metal-ceramic laminate according to any one of claims 1 to 3, wherein the ceramic film contains silicon nitride. The metal-ceramic laminate according to any one of claims 1 to 4, wherein the metal film contains copper. The ceramic laminate according to any one of claims 1 to 5, wherein the base material is a metal material. An insulated heat-dissipating member, characterized in that it is composed of the metal-ceramic laminate according to any one of claims 1 to 6.

Images