JP7208439B2 - Ceramic circuit board, electronic device, metal member, and method for manufacturing ceramic circuit board - Google Patents

Description

TECHNICAL FIELD The present invention relates to a ceramic circuit board, an electronic device, a metal member, and a method for manufacturing a ceramic circuit board.

2. Description of the Related Art Ceramic circuit boards, in which metal members are bonded to ceramic substrates, are widely used for electronic parts, mechanical parts, and the like. For example, electronic devices in which semiconductor elements are mounted on ceramic circuit boards are used in power devices that require high-voltage and large-current operation for electric railways, vehicles, and industrial machinery.
As one of the methods of joining the ceramic substrate and the metal member, there is a method of joining the ceramic substrate and the metal member using a brazing material. In this case, generally, a brazing material containing silver, copper, and an active metal is applied to the ceramic substrate, a metal member is placed on the brazing material, and the ceramic substrate and the metal member are bonded together by heat treatment at an appropriate temperature. to join.

For example, Patent Document 1 discloses a method for manufacturing a power module substrate in which a metal plate stamped by press working is laminated on one side of a ceramic substrate and joined by brazing. The height of the burrs on the metal plate is set to 0.021 mm or less, the thickness of the fractured surface is set to 0.068 mm or more, and the surface on which the burrs are generated is overlapped with one surface of the ceramic substrate. A method for manufacturing a power module substrate is disclosed, which is characterized by laminating and brazing.

JP 2016-039163 A

According to the inventors' studies, in the method disclosed in Patent Document 1, in the process of joining a metal member to a ceramic substrate, the brazing filler metal creeps up onto the surface of the metal member, and the crawled-up brazing filler metal lowers solder wettability. It turned out that there is a case. This is because when attempting to suppress the brazing filler metal from creeping up due to burrs generated on the metal plate during press working, it is difficult to precisely control the height of the burrs over the entire circumference of the metal plate. This is probably because the brazing filler metal seeps out from relatively low portions.

According to the present invention, in a ceramic circuit board formed by bonding a plate-like metal member to at least one surface of a ceramic substrate via a brazing material,
The metal member has a first surface facing the ceramic substrate and a second surface opposite to the first surface,
The ceramic circuit board is provided, wherein the first surface has a roughened portion on the outer edge thereof, the surface roughness of which is rougher than that of the central portion of the first surface.

Further, according to the present invention, there is provided an electronic device comprising the ceramic circuit board.

Further, according to the present invention, a plate-shaped metal member that is bonded to one surface of a ceramic substrate with a brazing material,
The metal member has a first surface facing the ceramic substrate and a second surface opposite to the first surface,
The metal member is provided, wherein the first surface has a roughened portion on the outer edge thereof, the surface roughness of which is rougher than that of the central portion of the first surface.

Further, according to the present invention, the step of joining a plate-like metal member to at least one surface of the ceramic substrate via a brazing material is provided, and the metal member has a first surface facing the ceramic substrate and the second surface. a second side opposite to the first side,
The method for manufacturing a ceramic circuit board is provided, wherein the first surface has a roughened portion on the outer edge thereof, the surface roughness of which is rougher than that of the central portion of the first surface.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a ceramic circuit board in which, when a plate-like metal member is joined to a ceramic substrate via a brazing material, the brazing material is prevented from creeping up onto the surface of the metal member, and an electronic device comprising the ceramic circuit board. , a metal member to be bonded to a ceramic substrate, and a method for manufacturing a ceramic circuit substrate.

It is a sectional view showing typically composition of a ceramics circuit board concerning this embodiment. 1 is a top view schematically showing the configuration of a ceramic circuit board according to this embodiment; FIG. FIG. 2 is a cross-sectional view schematically showing the structure of the metal member of the ceramic circuit board according to the present embodiment; FIG. 3 is a top view schematically showing the structure of the metal member of the ceramic circuit board according to the present embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in all the drawings, the same constituent elements are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. Also, the drawings are schematic diagrams and do not correspond to actual dimensional ratios.

<Ceramic circuit board>
First, the outline of the ceramic circuit board according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG.
FIG. 1 is a cross-sectional view schematically showing the overall configuration of a ceramic circuit board 100 according to this embodiment. A ceramic circuit board 100 according to this embodiment includes a ceramic board 10 , a brazing material 20 , and a plate-like metal member 30 . A plate-like metal member 30 is bonded to at least one surface of the ceramic substrate 10 via a brazing material 20, and the ceramic substrate 10, the brazing material 20, and the plate-like metal member 30 are fixed to each other by bonding.

A ceramic substrate 10 has a first surface 11 and a second surface 12 . A plate-like metal member 30 is joined to the upper surface of the second surface 12 of the ceramic substrate 10 via a brazing material 20 . The structure of the ceramic circuit board according to the present embodiment is not limited to the above structure. For example, as shown in FIG. A plate-shaped metal member 30 may be joined, or as shown in FIG. However, it is preferable to use a ceramic circuit board 100 in which plate-like metal members 30 are joined to both sides of the ceramic board 10 via a brazing material 20 . Further, FIG. 2 shows a top view schematically showing the ceramic circuit board 100 according to this embodiment. The ceramic circuit board 100 may have one metal member 30 bonded to each of the first surface 11 and the second surface 12, or may have one metal member 30 bonded to the first surface 11 and the second Two or more metal members 30 may be bonded to the surface 12, or two or more metal members 30 are bonded to the first surface 11 and one metal member 30 is bonded to the second surface 12. Alternatively, two or more metal members 30 may be bonded to each of the first surface 11 and the second surface 12 . The metal member 30 preferably has a polygonal shape when viewed from above, and may be rectangular. can also

Each configuration of the ceramic circuit board according to the present embodiment will be described in detail below.

<Metal member>
The configuration of the metal member 30 of the ceramic circuit board 100 of this embodiment will be described in detail with reference to FIGS. 3 and 4. FIG. FIG. 3 is a cross-sectional view schematically showing the structure of the metal member 30 of the ceramic circuit board 100 of this embodiment. FIG. 4 is a top view schematically showing the structure of the metal member 30 of the ceramic circuit board 100 of this embodiment.

In this embodiment, the metal member 30 has a first surface 31 facing the ceramic substrate, a second surface 32 opposite to the first surface 31, and end surfaces 33 existing between the outer peripheral ends of both surfaces. and The first surface 31 has a roughened portion 52 having a rougher surface roughness than the central portion 51 of the first surface 31 at its outer edge portion 50 .

The outer edge portion 50 means an outer peripheral region existing on the first surface 31, and specifically refers to either region (1) or (2) below.
(1) A region that exists on the first surface 31 and is within 1 mm from the boundary 34 between the first surface 31 and the end surface 33 .
(2) A region existing on the first surface 31, and the distance from the boundary 34 between the first surface 31 and the end surface 33 is 10% of the length of the longest diagonal when the metal member 30 is viewed from above. area within.

In addition, in the present invention, the central portion 51 means an internal region existing on the first surface 31, and specifically refers to any one of the following regions.
A region that exists on the first surface 31, and the distance from the midpoint of the longest diagonal line when the metal member 30 is viewed from above is within 40% of the length of the longest diagonal line when the metal member 30 is viewed from above. area.
Here, the longest diagonal when the metal member 30 is viewed from above refers to, for example, 4a in FIG. 4(a) and 4b in FIG. 4(b).

In the present embodiment, the first surface 31 of the metal member 30 has a roughened portion 52 having a rougher surface roughness than the central portion 51 of the first surface 31 at the outer edge portion 50, so that the brazing material It becomes the ceramics circuit board 100 which can suppress the creeping of 20 more. That is, conventionally, in the brazing process of joining the ceramic substrate 10 and the metal member 30 via the brazing filler metal 20, the brazing filler metal 20 runs along the end surface 33 of the metal member 30 at the joining end portion to the upper surface of the metal member 30. (second surface 32) in some cases, and when a semiconductor chip or the like is mounted on the top surface (second surface 32) of metal member 30 in a later process, solder wettability is affected by the crimped brazing material 20. This leads to poor soldering and poor appearance, which is one of the causes of lower yield. According to the present invention, by providing the roughened portion 52 on the outer edge portion 50 of the metal member, the surplus brazing filler metal 20 is trapped in the surface of the roughened portion 52 with an increased surface area and a slight gap, and the brazing filler metal 20 can be suppressed from creeping up from the lower surface of the metal member 30 to the end surface 33 . As a result, it is possible to prevent deterioration of solder wettability and occurrence of poor appearance.

In addition, when a convex projection is provided on the first surface 31 of the metal member 30 by burrs or the like generated when the metal member 30 is punched, and the projection suppresses the brazing filler metal 20 from creeping up, the metal plate ( If there is a part of the metal member 30) with a high protrusion, the brazing filler metal 20 will seep out from the protrusion with a low height, and there is a risk that the brazing filler metal 20 will rise significantly. The provision of protrusions on the surface of the metal member 30 may impair the reliability of the bonding between the metal member 30 and the ceramic substrate 10 .
According to the present invention, it is possible to suppress the brazing material 20 from creeping up without these risks, suppress the occurrence of the brazing material seeping out, and improve the solderability with the semiconductor chip or the like mounted on the metal member 30. can be improved.

The roughened portion 52 exists in all or part of the outer edge portion 50, and preferably occupies 50% or more of the area of the outer edge portion 50, and more preferably 80% or more.
One roughened portion 52 may exist on the outer edge portion 50 , or a plurality of roughened portions 52 may exist. preferably.

The roughened portion 52 preferably has a surface roughness greater than that of the central portion 51 of the first surface 31 . As the surface roughness, the arithmetic mean roughness Ra defined in JIS B0601-1994 (hereinafter referred to as "surface roughness Ra") can be used. Surface roughness Ra can be measured as follows.

The surface roughness Ra can be measured using a contact surface roughness meter based on JIS B0601-1994.

The surface roughness Ra of the roughened portion 52 is preferably 0.5 μm or more and 2 μm or less. The lower limit of the surface roughness Ra is more preferably 0.8 μm or more, particularly preferably 1.2 μm or more. The upper limit of the surface roughness Ra is more preferably 2 μm or less, particularly preferably 2 μm or less.
By setting the surface roughness Ra of the roughened portion 52 within the above numerical range, it is possible to more reliably suppress the brazing filler metal from creeping up.

In this embodiment, the length of the roughened portion 52 in the thickness direction cut surface along any diagonal line of the metal member 30 is within the range of the outer edge portion 50 described above, and the roughened portion 52 of a certain area is formed. By having it, the brazing material 20 can be more reliably suppressed from creeping up. Here, the cross section in the thickness direction along the diagonal line of the metal member 30 means a cross section taken along broken lines a to d in FIG. 2, for example.
Further, as shown in FIG. 3B, in the outer edge portion 50, the roughened portion 52 includes, for example, the outermost periphery of the outer edge portion 50 (roughened portion 52A), the central portion of the outer edge portion 50 (roughened portion 52B), and , the innermost circumference of the outer edge portion 50 (roughened portion 52C).

Where x is the surface roughness Ra of the roughened portion 52 and y is the surface roughness of the central portion 51, x/y is preferably 2 or more and 10 or less. The lower limit is more preferably 2.5 or higher, and even more preferably 2.75 or higher. The upper limit is more preferably 8.0 or less, and even more preferably 7 or less. When x/y is within such a range of values, it is possible to suppress the brazing filler metal 20 from creeping up and maintain good bondability between the metal member 30 and the ceramic substrate 10 .

In addition to the shape of the metal member 30, the amount of application of the brazing filler metal 20 also affects the crawlability of the brazing filler metal 20. FIG. The applied amount of the brazing material 20 can be, for example, 2 μm or more and 40 μm or less in terms of the dry film thickness of the brazing material paste before the joining process.

As the method for manufacturing the metal member 30 having the roughened portion 52 according to the present embodiment, the outer edge portion 50 of the first surface 31 of the metal member 30 is roughened to have a rougher surface than the central portion 51 . The method is not particularly limited as long as it can provide the portion 52, but examples include a method of roughening by a mechanical method, and specifically, polishing, sandblasting, or the like can be used.

Metals used for the metal member 30 according to the present embodiment include copper, aluminum, iron, nickel, chromium, silver, molybdenum, and cobalt alone or alloys thereof. As will be described later, a copper plate is preferable from the viewpoint of joining the metal member 30 to the ceramic substrate 10 with a silver-copper-based brazing material containing an active metal, and from the viewpoint of conductivity and heat dissipation.

If a copper plate is used, its purity is preferably 90% or higher. By setting the purity to 90% or more, the ceramic circuit board 100 has sufficient conductivity and heat dissipation. A highly reliable ceramic circuit board 100 can be obtained.

Although the thickness of the metal member 30 according to this embodiment is not particularly limited, it is generally 0.1 mm or more and 1.5 mm or less. The thickness of the metal member 30 is preferably 0.2 mm or more from the viewpoint of heat dissipation, and preferably 0.5 mm or less from the viewpoint of heat resistance cycle characteristics.

<Ceramic substrate>
The ceramic substrate 10 used in the ceramic circuit substrate 100 according to the present embodiment is not particularly limited, and includes nitride ceramics such as silicon nitride and aluminum nitride, and oxide ceramics such as aluminum oxide and zirconium oxide. , carbide ceramics such as silicon carbide, and boride ceramics such as lanthanum boride. As will be described later, non-oxide ceramics such as aluminum nitride and silicon nitride are suitable from the viewpoint of joining the metal member 30 to the ceramic substrate 10 with a silver-copper brazing material containing an active metal. An aluminum nitride substrate is preferred from the viewpoint of excellent thermal conductivity.

Although the thickness of the ceramic substrate 10 according to this embodiment is not particularly limited, it is preferably 0.2 mm or more and 1.5 mm or less. By setting it within the above numerical range, sufficient strength and durability can be maintained, and thermal resistance can be suppressed.

<Brazing material>
In the ceramic circuit board 100 according to the present embodiment, the brazing material 20 may contain at least one active metal selected from titanium, zirconium, hafnium, niobium, tantalum, vanadium, aluminum, and tin. preferable. The Ag/Cu ratio in the blending of the brazing filler metal 20 is such that the Ag/Cu eutectic composition of 72% by mass:28% by mass is increased to prevent the Cu-rich phase from becoming coarse, and the Ag A continuous rich phase can form a brazing filler metal layer structure.
Further, when the amount of Ag powder mixed is large and the amount of Cu powder mixed is small, the Ag powder may not be completely dissolved during bonding and may remain as bonding voids. Therefore, the compounding ratio of Ag powder, Cu powder, Sn powder, or In powder is Ag powder: 85.0 parts by mass or more and 95.0 parts by mass or less, Cu powder: 5.0 parts by mass or more and 13.0 parts by mass or less. , Sn powder or In powder: 0.4 parts by mass or more and 3.5 parts by mass or less. By setting the value within the above numerical range, the melting temperature of the brazing filler metal 20 can be prevented from rising excessively, joining can be performed at an appropriate temperature, and the thermal stress caused by the difference in thermal expansion coefficient during joining can be reduced. and improve heat resistance cycle resistance.

The amount of active metal such as titanium added is preferably 1.5 parts by mass or more and 5.0 parts by mass or less with respect to a total of 100 parts by mass of Ag powder, Cu powder, Sn powder or In powder. By appropriately adjusting the additive amount of the active metal, the wettability to the ceramic plate can be further improved, and the occurrence of poor bonding can be further suppressed. In addition, the remaining unreacted active metal can be suppressed, and discontinuity of the Ag-rich phase can be suppressed.

In the ceramic circuit board 100 according to this embodiment, the thickness of the brazing material 20 is not particularly limited as long as the ceramic board 10 and the metal member 30 can be joined. It is typically 3 μm or more and 40 μm or less, preferably 4 μm or more and 25 μm or less, more preferably 5 μm or more and 15 μm or less. By setting the value within the above numerical range, the ceramic circuit board 100 having excellent heat dissipation and excellent reliability can be obtained.

<Method for producing ceramic circuit board>
A method for manufacturing the ceramic circuit board 100 according to this embodiment will be described below.
The manufacturing method of this embodiment includes a joining step of joining a plate-shaped metal member 30 to at least one surface of the ceramic substrate 10 via a brazing material 20. having a surface 31 and a second surface 32 opposite the first surface 31;
A method for manufacturing a ceramic circuit board 100, wherein the first surface 31 has a roughened portion 52 having a rougher surface roughness than a central portion 51 of the first surface 31 at the outer edge portion 50 thereof.
First, the ceramic substrate 10 and the metal member 30 are prepared. The aspects of the ceramic substrate 10 and the metal member 30 are as described above.
Next, a brazing paste is prepared. The composition of the metal components of the brazing paste (brazing material 20) is as described above. Ag powder: 85.0 to 95.0 parts by mass, Cu powder: 5.0 to 13.0 parts by mass. Sn powder or In powder: 0.4 parts by mass or more and 3.5 parts by mass or less are preferably mentioned below. The amount of active metal such as titanium added is preferably 1.5 parts by mass or more and 5.0 parts by mass or less with respect to a total of 100 parts by mass of Ag powder, Cu powder, Sn powder or In powder.
A brazing filler metal paste can be obtained by mixing these metal powders, a resin, a solvent, and, if necessary, a dispersant and the like by a known method.
Subsequently, a brazing material paste is applied to one side or both sides of the ceramic substrate 10 . The coating method is not particularly limited, and the coating can be performed, for example, by screen printing. It is preferable that the dry film thickness of the applied brazing filler metal paste is, for example, 1 μm or more and 50 μm or less.

Next, the metal member 30 is overlaid so as to be in contact with the brazing paste applied to the ceramic substrate 10 and heated in a heating furnace to join the ceramic substrate 10 and the metal member 30 together.
In this embodiment, the bonding temperature for bonding the ceramic substrate 10 and the metal member 30 is preferably 780°C or higher and 850°C or lower, and more preferably lower than 800°C. Also, the degree of vacuum during bonding is preferably 1×10 ⁻³ Pa or less. Moreover, it is desirable that the holding time at the bonding temperature is 10 minutes or more and 60 minutes or less.
By setting the bonding temperature, the degree of vacuum, and the bonding time within the above ranges, the compound containing the active metal is sufficiently generated, and the ceramic substrate 10 and the metal member 30 can be bonded over the entire surface. Also, if the bonding temperature is high or the holding time is too long, the uneven thickness of the brazing material layer (brazing material 20) after bonding may increase. By setting the time within the above range, thickness unevenness of the brazing material 20 after joining can be reduced.

The ceramic circuit board 100 according to the present embodiment can also be the ceramic circuit board 100 in which at least part of the metal member 30 is removed by etching, if necessary. That is, the ceramic circuit board 100 according to this embodiment can also undergo a circuit pattern forming process by etching. When forming a circuit pattern on the ceramic circuit board 100 according to the present embodiment, etching resist can be applied to the metal member 30 and etched. There are no particular restrictions on the etching resist, and known UV-curing and heat-curing resists can be used. Also, the method of applying the etching resist is not particularly limited, and for example, a known application method such as a screen printing method can be employed.
The etchant is not particularly limited, and a known etchant can be used. When the metal member 30 is a copper plate, ferric chloride solution, cupric chloride solution, sulfuric acid, hydrogen peroxide solution, etc. are used. ferric chloride solution and cupric chloride solution are preferred.

In some cases, the brazing material 20, its alloy layer, nitride layer, etc. may remain on the ceramic circuit board 100 from which unnecessary metal parts have been removed by etching. They are generally removed using a solution containing acid and hydrogen peroxide. After circuit formation, the etching resist can be removed by a known method. The peeling method is not particularly limited, and for example, a method of immersion in an alkaline aqueous solution can be used.

As described above, the ceramic circuit board 100 in which the ceramic substrate 10 and the metal member 30 are bonded via the brazing material 20 can be obtained.

The ceramic circuit board 100 according to this embodiment can be used as an electronic device by mounting a semiconductor chip or the like on the second surface 32 of the metal member 30, for example.
The ceramic circuit board 100 according to this embodiment can be particularly suitably applied to power devices that require high-voltage and large-current operation, such as those for electric railways, vehicles, and industrial machinery.
It should be noted that the present invention is not limited to the above-described embodiments, and includes modifications, improvements, etc. within the scope of achieving the object of the present invention.
For example, the roughened portion 52 is not limited to a configuration in which the surface roughness is provided in the outer edge portion 50 and is rougher than the central portion 51 of the first surface 31. Also, the surface roughness may be roughened. That is, regardless of the surface roughness of the central portion 51, the region adjacent to the roughened portion 52 of the outer edge portion 50 on the central side of the surface only needs to be a region with less surface roughness than the roughened portion 52. .

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to the description of these Examples. Table 1 shows the measurement results of the surface roughness Ra (outer edge portion, center portion) and evaluation (brazing filler metal creeping, bondability).

A silicon nitride substrate (50 mm×50 mm, thickness 0.32 mm) and a copper plate (50 mm×50 mm, thickness 0.8 mm) were prepared.

(roughening treatment)
The copper plate was roughened at its outer edge 50 by the following method.
In Examples 1 to 4 and Comparative Example 1, No. 400 sandpaper was used, and the surface roughness was adjusted by rubbing strength.
In Comparative Examples 2 and 3, No. 1000 sandpaper was used, and the surface roughness was adjusted by rubbing strength.
For Comparative Example 1, the central portion 51 was also roughened with sandpaper.
Note that the distance from the boundary 34 between the first surface 31 and the end surface 33 in the region existing on the first surface 31 is within 10% of the length of the longest diagonal when the metal member 30 is viewed from above. is defined as the outer edge portion 50, and the ratio of roughening is such that the copper plate is roughened from the outer side and the area ratio shown in the table is roughened.
The surface roughness of the central portion 51 other than Comparative Example 1 was also adjusted using No. 1000 sandpaper.
A method for measuring the surface roughness Ra is as described later.

A brazing paste (Ag--Cu--Ti based brazing material) was prepared.
The above brazing paste was printed on a silicon nitride substrate by screen printing and dried. The brazing paste was applied so that the thickness after drying was 20 μm.
After that, the copper plate 1 was overlaid on the brazing material, and the copper plate and the silicon nitride substrate were joined in a vacuum atmosphere to manufacture the ceramic circuit board 100 .

<Surface roughness measurement method>
The surface roughness Ra was measured according to JIS B0601-1994 using a contact surface roughness meter.
Regarding the measurement range, the outer edge portion 50 (roughened portion 52) is a region within 1 mm from the boundary 34 between the first surface 31 and the end surface 33, and the central portion 51 is a range of 1 mm at the center of the diagonal line. is.

<Brazing material riseability>
The appearance of the obtained ceramic circuit board 100 was observed. In the evaluation of brazing filler metal rise in Table 1, "◎" indicates "no brazing filler metal rise", "○" indicates "a small amount of brazing filler metal rise", and "△" indicates "brazing filler metal rise can be confirmed."'X' indicates 'clear rise of the brazing material was confirmed'.
In Examples 1 and 2, it was not confirmed that the brazing filler metal 20 crawled up onto the second surface 32 (upper surface) of the copper plate. In Examples 3 and 4, the brazing filler metal was slightly raised, but the amount was very small. In Comparative Example 1, the surface roughness Ra of the outer edge portion 50 and the central portion 51 was 2, but the bondability was unsuitable and could not be evaluated. In Comparative Example 2, rising of the brazing filler metal could be confirmed, and in Comparative Example 3, rising of the brazing filler metal could be clearly confirmed.
<Joinability>
Whether or not the ceramic substrate and the copper plate could be bonded was evaluated by visual observation. In Table 1, those that were able to be bonded were evaluated as "◯", those that could not be bonded were evaluated as "x", and those that were bonded but were insufficient were evaluated as "Δ". In Examples 1 to 4, bonding was confirmed by visual observation. In Comparative Example 1, the bondability was unsuitable. In Comparative Example 2, bonding was insufficient, and in Comparative Example 3, bonding was appropriate.

This application claims priority based on Japanese Patent Application No. 2020-060607 filed on March 30, 2020, and the entire disclosure thereof is incorporated herein.

10 Ceramic substrate 11 First surface 12 Second surface 20 Brazing material 30 Metal member 31 First surface 32 Second surface 33 End surface 34 Boundary 50 Outer edge portion 51 Central portion 52 Roughened portion 52A Roughened portion 52B Roughened Part 52C Roughened part 100 Ceramic circuit board

Claims (11)

A ceramic circuit board formed by bonding a plate-like metal member to at least one surface of a ceramic substrate via a brazing material,
The metal member has a first surface facing the ceramic substrate and a second surface opposite to the first surface,
The first surface has a roughened portion having a rougher surface roughness than the central portion of the first surface on its outer edge,
The metal member is rectangular,
The ceramic circuit board, wherein the roughened portion has a surface roughness Ra larger than that of the central portion of the first surface, and the surface roughness Ra is 0.5 μm or more and 2 μm or less. 2. The ceramic circuit board according to claim 1, wherein said metal member is a Cu plate. 3. The ceramic circuit board according to claim 1, wherein said brazing material contains at least one metal selected from titanium, zirconium, hafnium, niobium, tantalum, vanadium, aluminum and tin. 4. The ceramic circuit board according to claim 1, wherein said ceramic substrate is at least one selected from silicon nitride and aluminum nitride. 5. The ceramic circuit board according to any one of claims 1 to 4, wherein the plate-shaped metal member is joined to both surfaces of the ceramic substrate via a brazing material. The ceramic circuit board according to any one of claims 1 to 5, wherein said roughened portion is provided so as to circulate in said outer edge portion. 7. The ceramic circuit board according to claim 1, wherein said roughened portion is provided in a region within 1 mm from the end surface of said first surface. An electronic device comprising the ceramic circuit board according to any one of claims 1 to 7. 9. The electronic device according to claim 8, wherein the electronic device is a power device. A plate-shaped metal member bonded to one surface of a ceramic substrate with a brazing material,
The metal member has a first surface facing the ceramic substrate and a second surface opposite to the first surface,
The first surface has a roughened portion having a rougher surface roughness than the central portion of the first surface on its outer edge,
The metal member is rectangular,
The metal member, wherein the roughened portion has a surface roughness Ra larger than that of the central portion of the first surface, and the surface roughness Ra is 0.5 μm or more and 2 μm or less. A method for manufacturing a ceramic circuit board, comprising a bonding step of bonding a plate-like metal member to at least one surface of a ceramic substrate via a brazing material,
The metal member has a first surface facing the ceramic substrate and a second surface opposite to the first surface,
The first surface has a roughened portion having a rougher surface roughness than the central portion of the first surface on its outer edge,
The metal member is rectangular,
The method for manufacturing a ceramic circuit board, wherein the roughened portion has a surface roughness Ra larger than that of the central portion of the first surface, and the surface roughness Ra is 0.5 μm or more and 2 μm or less.

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