Ceramic copper circuit board and semiconductor device using the same

Abstract

To provide a ceramic copper circuit board using a Ag-free brazing filler metal layer, wherein the brazing filler metal layer of the ceramic copper circuit board includes a protruding part, and a semiconductor device using the same.SOLUTION: A ceramic copper circuit board according to the embodiment includes a ceramic substrate, and a plurality of copper circuit parts bonded respectively via brazing filler metal layers on at least one surface of the ceramic substrate. The brazing filler metal layer does not contain Ag and contains Cu, Ti, and one or two kinds selected from Sn and In. The brazing filler metal layer includes a junction provided between the ceramic substrate and the copper circuit part, and a first protruding part provided around the junction and having a titanium content in the range of 70 mass% or more and 100 mass% or less. When the thickness of the copper circuit part is D and the shortest distance between adjacent copper circuit parts is P, the thickness D of the copper circuit part is 0.1 mm or more, and a region satisfying 1≤P / D≤3 is included.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments described below relate to a ceramic copper circuit board and a semiconductor device using the same. [Background technology]

[0002] In recent years, power modules have been used in electric vehicles and trains to control large currents and voltages due to the increasing performance of industrial equipment and global environmental issues. The heat generated by the semiconductor elements mounted in these devices is also continuing to increase. For this reason, heat dissipation performance has become important for circuit boards used in power modules. Ceramic-metal bonded circuit boards, in which a metal plate such as copper or aluminum is bonded to a highly thermally conductive ceramic substrate, are widely used. In addition, the active metal bonding method using brazing filler metal is widely used as a method for bonding a ceramic substrate to a copper plate. The brazing filler metal used in the active metal bonding method is called an active metal brazing filler metal. For example, Japanese Patent No. 6158144 (Patent Document 1) discloses a ceramic circuit board using a brazing filler metal layer containing Ag, Cu, and Ti. In Patent Document 1, an overhanging portion of the brazing filler metal layer is formed on the ceramic circuit board. According to Patent Document 1, the TCT characteristics are improved by forming an overhanging portion of the brazing filler metal layer. A joining method using a brazing filler metal layer containing Ag, Cu, and Ti, as in Patent Document 1, is called an active metal joining method. Generally, in the active metal joining method, an active metal is contained in the brazing filler metal, and Ag, Cu, and Ti are often used as the joining brazing filler metal. Among the joining brazing filler metals, Ag is an expensive element. For example, Japanese Patent Laid-Open Publication No. 2003-283064 (Patent Document 2) discloses the use of a CuSnTi-based brazing filler metal that does not contain Ag. The ceramic circuit board of Patent Document 2 does not use Ag in the brazing filler metal. Therefore, the brazing filler metal layer has good etching properties. Patent Document 2 also discloses an active metal brazing filler metal that does not contain Ag. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6158144 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-283064 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 2, the etching property of the brazing filler metal layer is improved. However, it is not possible to form an overhanging portion of the brazing filler metal layer as in Patent Document 1. Since an overhanging portion of the brazing filler metal layer is not formed, there is a problem that the TCT characteristics of the ceramic circuit board are deteriorated. The ceramic copper circuit board according to the embodiment is characterized in that the protruding portion of the brazing filler metal layer is controlled in a ceramic copper circuit board using a brazing filler metal layer that does not contain Ag. [Means for solving the problem]

[0005] A ceramic copper circuit board according to an embodiment includes a ceramic substrate and multiple copper circuit portions bonded to at least one surface of the ceramic substrate via a brazing filler metal layer. The brazing filler metal layer does not contain Ag, but contains Cu, Ti, and one or two selected from Sn and In. The brazing filler metal layer includes a joint portion provided between the ceramic substrate and the copper circuit portion and a first protrusion portion provided around the joint portion and having a titanium content in the range of 70% by mass to 100% by mass. When the thickness of the copper circuit portion is D and the shortest distance between adjacent copper circuit portions is P, the thickness D of the copper circuit portion is 0.1 mm or more and includes a portion where 1≦P / D≦3. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a schematic diagram showing an example of a ceramic copper circuit board according to an embodiment. [Figure 2] FIG. 2 is a schematic view showing another example of a ceramic copper circuit board according to an embodiment. [Figure 3] 2 is a schematic diagram showing an example of a protruding portion of a ceramic copper circuit board according to an embodiment. FIG. [Figure 4] 4 is a schematic diagram showing the length of a first protruding portion and the length of the entire protruding portion. FIG. [Figure 5] FIG. 10 is a conceptual diagram illustrating a method for measuring the inclination angle of the side surface of a copper circuit portion. [Figure 6] 1 is a schematic diagram showing an example of a semiconductor device according to an embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0007] A ceramic copper circuit board according to an embodiment includes a ceramic substrate and multiple copper circuit portions bonded to at least one surface of the ceramic substrate via a brazing filler metal layer. The brazing filler metal layer does not contain Ag, but contains Cu, Ti, and one or two selected from Sn and In. The brazing filler metal layer includes a joint portion provided between the ceramic substrate and the copper circuit portion and a first protrusion portion provided around the joint portion and having a titanium content in the range of 70% by mass to 100% by mass. When the thickness of the copper circuit portion is D and the shortest distance between adjacent copper circuit portions is P, the thickness D of the copper circuit portion is 0.1 mm or more and includes a portion where 1≦P / D≦3. Fig. 1 is a schematic diagram showing an example of a ceramic copper circuit board according to an embodiment. Fig. 2 is a schematic diagram showing another example of a ceramic copper circuit board according to an embodiment. Fig. 3 is a schematic diagram showing an example of an overhanging portion of a ceramic copper circuit board according to an embodiment. In Figs. 1 to 3, reference numeral 1 denotes a ceramic copper circuit board, reference numeral 2 denotes a ceramic substrate, reference numeral 3 denotes a copper circuit portion, reference numeral 4 denotes a brazing material layer, reference numeral 5 denotes a joint portion, reference numeral 6 denotes a first overhanging portion, reference numeral 7 denotes a second overhanging portion, and reference numeral 8 denotes a copper heat sink. L1 denotes the length of the first overhanging portion 6, and L2 denotes the length of the entire overhanging portion. The ceramic copper circuit board 1 according to the embodiment has a structure in which a copper circuit portion 3 is bonded to at least one surface of a ceramic substrate 2 via a brazing material layer 4. As shown in FIG. 1, the copper circuit portion 3 may be bonded to one surface of the ceramic substrate 2, and a copper heat sink 8 may be bonded to the other surface of the ceramic substrate 2. As shown in FIG. 2, a plurality of copper circuit portions 3 may be bonded to one surface of the ceramic substrate 2. The copper circuit portion 3 may be provided instead of the copper heat sink 8.

[0008] Examples of the ceramic substrate 2 include a silicon nitride substrate, an aluminum nitride substrate, an aluminum oxide substrate, and a zirconium oxide substrate. The ceramic substrate 2 is preferably either a silicon nitride substrate or an aluminum nitride substrate. The silicon nitride substrate and the aluminum nitride substrate are nitride-based ceramic substrates. As will be described later, a titanium nitride layer can be formed on the nitride-based ceramic substrate by an active metal bonding method. Aluminum oxide substrates and zirconium oxide substrates are oxide-based ceramic substrates. A titanium oxide layer can be formed on an oxide-based ceramic substrate by an active metal bonding method. Comparing nitride-based ceramic substrates with oxide-based ceramic substrates, nitride-based ceramic substrates have higher thermal conductivity. From this perspective, it is preferable to use nitride-based ceramic substrates. The thickness of the ceramic substrate 2 is preferably 0.1 mm or more and 3 mm or less. If the substrate thickness is less than 0.1 mm, the strength may decrease. If the substrate thickness is greater than 3 mm, the ceramic substrate may become a thermal resistor, which may reduce the heat dissipation performance of the bonded structure. For this reason, the thickness of the ceramic substrate 2 is preferably 0.1 mm or more and 3 mm or less, and more preferably 0.2 mm or more and 1 mm or less.

[0009] The three-point bending strength of the silicon nitride substrate is preferably 600 MPa or more. The thermal conductivity of the silicon nitride substrate is preferably 80 W / m·K or more. By increasing the strength of the silicon nitride substrate, the substrate thickness can be reduced. For this reason, the three-point bending strength of the silicon nitride substrate is preferably 600 MPa or more, and more preferably 700 MPa or more. The thickness of the silicon nitride substrate can be reduced to 0.40 mm or less, and even 0.30 mm or less. The three-point bending strength of an aluminum nitride substrate is approximately 300 to 450 MPa. On the other hand, the thermal conductivity of an aluminum nitride substrate is 160 W / m·K or more. Because the strength of an aluminum nitride substrate is low, the substrate thickness is preferably 0.60 mm or more. Copper plates or copper alloy plates can be used for the copper circuit section 3 and the copper heat sink 8. The copper circuit section 3 and the copper heat sink 8 are preferably made of oxygen-free copper. As specified in JIS-H-3100 (ISO 1337, etc.), oxygen-free copper is copper with a copper purity of 99.96 wt% or more. Increasing the thickness of the copper circuit section 3 and the copper heat sink 8 can improve the current-carrying capacity and heat dissipation performance. For this reason, the thickness of the copper circuit section 3 and the copper heat sink 8 is preferably 0.1 mm or more, and more preferably 0.6 mm or more. More preferably, the thickness of the copper circuit section 3 and the copper heat sink 8 is 0.8 mm or more.

[0010] The copper circuit portion 3 and the copper heat sink 8 are each joined to the ceramic substrate 2 via a brazing filler metal layer 4. The brazing filler metal layer 4 includes a joint portion 5. The joint portion 5 is provided between the ceramic substrate 2 and the copper circuit portion 3 or between the ceramic substrate 2 and the copper heat sink 8. The brazing filler metal layer 4 further includes a protruding portion provided around the joint portion 5 in the in-plane direction. The in-plane direction is a direction parallel to the surface of the ceramic substrate 2. The brazing filler metal layer 4 is provided on that surface of the ceramic substrate 2. The protruding portion protrudes from the end of the copper circuit portion 3 or the copper heat sink 8 along the in-plane direction. 1, the protruding portion includes a first protruding portion 6. In the first protruding portion 6, the titanium content is in the range of 70% by mass to 100% by mass. In the first protruding portion 6, the total titanium content and nitrogen content is preferably in the range of 90% by mass to 100% by mass. As shown in FIG. 2, the protruding portion may further include a second protruding portion 7. The second protruding portion 7 is provided between the joint portion 5 and the first protruding portion 6. The second protruding portion 7 has a titanium content of less than 70 mass %. The brazing material layer 4 has a structure in which the joint portion 5, the second protruding portion 7, and the first protruding portion 6 are connected to each other. The first protruding portion 6 is located outside the protruding portion. The second protruding portion 7 is located inside the protruding portion. As shown in Figure 3, the boundary between the joint 5 and the protruding portion is based on the edge of the copper circuit portion 3 or the copper heat sink 8. A line perpendicular to the surface of the ceramic substrate 2 is drawn from the edge of the copper circuit portion 3 or the copper heat sink 8. The portion protruding from this perpendicular line is the protruding portion. The protruding portion of the brazing material layer is also simply called the protruding portion.

[0011] The titanium content in the protruding portion is measured using scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX). Area analysis is performed on the protruding portion at any cross section of the ceramic copper circuit board 1. In the area analysis, the measurement area is set so that the entire protruding portion is the subject of analysis. The entire protruding portion refers to the portion of the brazing filler metal layer 4 other than the joint portion 5, and the entire portion that protrudes from the boundary between the ceramic substrate 2 and the protruding portion. When a copper plate is joined to a silicon nitride substrate using a Ti-containing brazing filler metal layer, a titanium nitride layer is formed on the surface of the silicon nitride substrate. The boundary between the silicon nitride substrate and the titanium nitride layer is the boundary between the ceramic substrate 2 and the brazing filler metal layer 4. In other words, the titanium nitride layer is part of the joint 5 and part of the protruding portion. For this reason, when analyzing the area, care must be taken to include the titanium nitride layer in the measurement area, but not the silicon nitride substrate. When a copper plate is joined to an oxide-based ceramic substrate using a Ti-containing brazing filler metal layer, a titanium oxide layer is formed on the surface of the oxide-based ceramic substrate. The boundary between the oxide-based ceramic substrate and the titanium oxide layer is the boundary between the ceramic substrate 2 and the brazing filler metal layer 4. When analyzing the area, care must be taken to ensure that the titanium oxide layer is included in the measurement area, but that the oxide-based ceramic substrate is not included in the measurement area. For SEM observation, a Field Emission SEM (FE-SEM) is used. EDX is sometimes called EDS. For FE-SEM, a JEOL JSM-7200F or an instrument with equivalent performance is used. For EDX, a JEOL EX-74600U4L2Q or an instrument with equivalent performance is used. The FE-SEM measurement conditions were an acceleration voltage of 15 kV, a magnification of 3000 times, and a field of view of 1200 μm 2 The thickness direction is set to 30 μm (thickness direction × width direction 40 μm). The thickness direction is the direction perpendicular to the surface of the ceramic substrate 2. The width direction is the direction parallel to the cross-sectional and in-plane directions. The EDX measurement conditions are set to 50 scans and a measurement speed of 0.2 ms / bit. When performing EDX area analysis, the capture pixel count is 256 × 198 pixels, the detection count is 3700 to 4100 cps (counts per second), and the quantitative map is 5 × 5 bits / point. Area analysis is sometimes called surface analysis. With EDX, it is effective to first investigate the elements that make up the brazing material layer using qualitative analysis using EDX, and then identify the elements to be identified before performing area analysis. When measuring the amount of titanium in the protruding portion of a ceramic copper circuit board 1 using a nitride ceramic substrate, the total of the metal components, silicon, nitrogen, and carbon is taken as 100% by mass. When measuring the amount of titanium in the protruding portion of a ceramic copper circuit board using an oxide ceramic substrate, the total of the metal components, oxygen, and carbon is taken as 100% by mass. Metal components of 0.01% by mass or more are measured. This is because amounts less than 0.01% by mass are below the detection limit of EDX. When a silicon nitride substrate is used as a nitride ceramic substrate, silicon and nitrogen diffuse into the brazing material layer. As a result, silicon and nitrogen are included in the measurement targets. Similarly, for aluminum nitride substrates, Al and nitrogen are included in the measurement targets. For aluminum oxide substrates, Al and oxygen are included in the measurement targets. For zirconium oxide substrates, Zr and oxygen are included in the measurement targets. Al and Zr are included in the measurement targets as types of metal components.

[0012] The first protruding portion 6 is a region where the titanium content is 70% by mass or more and 100% by mass or less. When a nitride ceramic substrate is used, the tip of the protruding portion can be composed of only titanium or titanium nitride. The first protruding portion 6 is preferably a region where the total titanium content and nitrogen content is 90% by mass or more and 100% by mass or less. The amount of titanium nitride in the first protruding portion 6 is counted assuming that all nitrogen detected by EDX constitutes titanium nitride (TiN). When an oxide ceramic substrate is used, the tip of the protruding portion can be composed of only titanium or titanium oxide. The first protruding portion 6 is preferably in a region where the total titanium content and oxygen content is 90% by mass or more and 100% by mass or less. The amount of titanium oxide in the first protruding portion 6 is counted assuming that all oxygen detected by EDX constitutes titanium oxide (TiO2). An example using a nitride ceramic substrate will be described below. When an oxide ceramic substrate is used, the titanium nitride in the protruding portion can be replaced with titanium oxide. As will be described later, the brazing material layer 4 contains Cu (copper), Ti (titanium), and one or two selected from Sn (tin) and In (indium). Components other than titanium and nitrogen in the first protruding portion 6 include Cu, Sn, and In. If a large amount of these components remains, migration is likely to occur between the copper circuit portions when the distance between adjacent copper circuit portions 3 is shortened. Migration is a phenomenon in which ionized metal migrates between electrodes due to the application of voltage when a circuit board is placed in a humid environment, causing a short circuit. Migration caused by ionized metal is called ion migration. In recent years, semiconductor devices have been used in a variety of industrial equipment. For example, electric vehicles are sometimes used in humid environments. In the active metal bonding method, Ag, Cu, Sn, In, Ti, and other brazing filler metals are used. Among these, Ti has a low ionization tendency and is resistant to moisture. Ti reacts with nitride-based ceramic substrates to form titanium nitride. The formation of titanium nitride can suppress the occurrence of migration. Therefore, the titanium content in the first protruding portion 6 must be within a range of 70% to 100% by mass. Furthermore, the total titanium content and nitrogen content in the first protruding portion 6 is preferably within a range of 90% to 100% by mass, and more preferably 99% to 100% by mass.

[0013] The titanium content in the second protruding portion 7 is less than 70 mass %. That is, the second protruding portion 7 contains 30 mass % or more of components other than titanium. As mentioned above, migration can be suppressed by increasing the amount of titanium (or titanium nitride) contained in the first protruding portion 6. On the other hand, if the amount of titanium (or titanium nitride) increases too much, the stress relaxation effect in the vicinity of the end of the copper circuit portion 3 or the copper heat sink 8 decreases. For this reason, it is effective for the titanium content of the second protruding portion 7 to be less than 70 mass %. In the second protruding portion 7, the Cu content is preferably 5 to 60 mass %, the Sn or In content is preferably 5 to 45 mass %, and the total content of Ti and titanium nitride is preferably 10 to less than 90 mass %. The presence of predetermined amounts of Cu and one or two selected from Sn and In can improve the stress relaxation effect near the end of the copper circuit portion 3. The brazing filler metal layer 4 contains Cu, Ti, and one or two elements selected from Sn and In. The Ag content in the brazing filler metal layer 4 is preferably 0% by mass or more and 10% by mass or less. The brazing filler metal layer 4 may contain elements other than Cu, Ti, Sn, and In. On the other hand, if the Ag content in the brazing filler metal layer 4 is high, it may be difficult to form the first protruding portion 6. For this reason, the Ag content in the brazing filler metal layer 4 is preferably 10% by mass or less. More preferably, the Ag content in the brazing filler metal layer 4 is 0% by mass, i.e., the brazing filler metal layer 4 does not contain Ag. An Ag content of 0% by mass means that the Ag content is below the detection limit (less than 0.01% by mass) by EDX. The brazing filler metal layer 4 may contain 10% by mass or less of metal elements other than Cu, Ti, Sn, and In. Examples of metal elements other than Cu, Ti, Sn, and In include one or more elements selected from carbon, magnesium, molybdenum, tungsten, and rhenium. The brazing layer 4 may contain these elements as long as the total content of these elements is 10 mass % or less.

[0014] The Cu content (mass%) of the joint 5 is defined as C1. The Cu content (mass%) of the second protruding portion 7 is defined as C2. The mass ratio C2 / C1 is preferably 0.7 or less. This indicates that the amount of Cu decreases in the order of joint 5 → second protruding portion 7 → first protruding portion 6 near the end of the copper circuit portion 3. By providing a gradient in the Cu content composition, the stress relaxation effect can be improved. If the mass ratio C2 / C1 exceeds 0.7, the difference between the Cu content of the second protruding portion 7 and the Cu content of the first protruding portion 6 becomes too large, which may reduce the stress relaxation effect. Although the lower limit of the mass ratio C2 / C1 is not particularly limited, it is preferably 0.1 or more. If the mass ratio C2 / C1 is less than 0.1, the amount of Cu in the second protruding portion 7 may be too small, which may reduce the stress relaxation effect. Therefore, the mass ratio C2 / C1 is preferably 0.1 or more and 0.7 or less, and more preferably 0.2 or more and 0.5 or less. The Cu amount in the joint 5, the Cu amount in the first protruding portion 6, and the Cu amount in the second protruding portion 7 are measured using the SEM-EDX area analysis described above. First, the brazing filler metal layer 4 is divided into a joint 5 and a protruding portion according to the position of the end of the copper circuit portion 3 or the copper heat sink 8. Next, the protruding portion is divided into a region of the first protruding portion 6 and a region of the second protruding portion 7 according to the Ti content. The average value of the Cu amount in the joint 5 is defined as the Cu amount in the joint 5. The average value of the Cu amount in the region of the first protruding portion 6 is defined as the Cu amount in the first protruding portion 6. The average value of the Cu amount in the region of the second protruding portion is defined as the Cu amount in the second protruding portion 7. To determine the amount of Cu in each of the bonding portion 5, the first protruding portion 6, and the second protruding portion 7, five measurement areas are analyzed using EDX, and the amount of Cu in each of the bonding portion 5, the first protruding portion 6, and the second protruding portion 7 included in each measurement area is measured. The average value of the Cu amount in the five measurement areas for each of the bonding portion 5, the first protruding portion 6, and the second protruding portion 7 is calculated, and the obtained average value is used as the Cu amount for each portion. The five measurement areas are obtained from five mutually different cross sections. Multiple cross sections passing through multiple sides of the copper circuit portion 3 in the ceramic copper circuit board 1 may be obtained, or multiple cross sections may be obtained from one side.

[0015] The Ti content (mass%) in the joint 5 is defined as C3. The Ti content (mass%) in the second protruding portion 7 is defined as C4. The mass ratio C4 / C3 is preferably 1.2 or less. By setting the mass ratio C4 / C3 to 1.2 or less, a gradient in the Ti content can be imparted to the composition from the joint 5 toward the second protruding portion 7. A mass ratio C4 / C3 exceeding 1.2 indicates that the second protruding portion 7 contains less Cu or Sn. There is no particular limit to the lower limit of the mass ratio C4 / C3, but it is preferably greater than 1. For this reason, the mass ratio C4 / C3 is preferably greater than 1 and less than 1.2. The above-mentioned SEM-EDX area analysis is used to measure the Ti content of each of the joint 5 and the second protruding portion 7. The average value of the Ti content in the region of the second protruding portion 7 is taken as the Ti content of the second protruding portion 7. The Ti content of the joint 5 is taken as the average value of the Ti content in a region 100 μm inward from the boundary between the joint 5 and the protruding portion. Regarding the Ti content of each of the joint 5 and the second protruding portion 7, five measurement areas are analyzed by EDX, and the Ti content of each of the joint 5 and the second protruding portion 7 included in each measurement area is measured. For each of the joint 5 and the second protruding portion 7, the average value of the Ti content in the five measurement areas is calculated, and the obtained average value is used as the Ti content of each part. The five measurement areas are obtained from five mutually different cross sections. Multiple cross sections passing through multiple sides of the copper circuit portion of the ceramic copper circuit board may be obtained, or multiple cross sections may be obtained from one side. The five cross sections for measuring the Cu content may be used to measure the Ti content along with the Cu content.

[0016] As shown in Fig. 3, the length of the first protruding portion 6 in the direction from the joint portion 5 toward the first protruding portion 6 is defined as L1. The length of the entire protruding portion in this direction is defined as L2. In this case, it is preferable that 0.3 ≤ L1 / L2 ≤ 1 is satisfied. More preferably, 0.5 ≤ L1 / L2 ≤ 0.8 is satisfied. As mentioned above, the presence of the first protruding portion 6 and the second protruding portion 7 suppresses migration and provides stress relaxation. Length L2 minus length L1 corresponds to the length of the second protruding portion 7. Controlling the lengths of the first protruding portion 6 and the second protruding portion 7 can further improve these properties. In particular, eliminating the inclusion of Ag in the joint portion 5 and the protruding portion of the brazing material layer can suppress Ag migration. An active metal brazing material is used to join the ceramic substrate 2 and the copper circuit portion 3. Active metal brazing materials generally contain metals such as Ag, Cu, Ti, Sn, and In, but Ag is the element most susceptible to migration among active metal brazing materials. Reducing the Ag content or eliminating Ag altogether can suppress Ag migration. The length (L1) of the first protrusion portion 6 and the length (L2-L1) of the second protrusion portion 7 are measured using the aforementioned SEM-EDX area analysis. Specifically, from the results of the area analysis, a region on the top surface of the protrusion portion with a titanium content of 70% by mass or more is identified. From the identified region, the region that extends to the tip of the protrusion portion is extracted. The tip of the protrusion portion is the point where the ceramic substrate 2 and the first protrusion portion 6 are in contact and is the farthest from the joint 5. From the extracted region, the point closest to the copper circuit portion 3 is identified. A line perpendicular to the surface of the ceramic substrate 2 is drawn from this point closest to the copper plate. The length from the tip of the protrusion portion to this perpendicular line is defined as the length L1 of the first protrusion portion 6. The length (L2-L1) obtained by subtracting the length L1 of the first protrusion portion 6 from the length L2 of the entire protrusion portion is defined as the length of the second protrusion portion 7. For example, if the region on the upper surface of the protruding portion where the titanium content is 70 mass % or more is discontinued, the length L1 of the first protruding portion is found using the region connected to the tip of the protruding portion. 4(a) to 4(c) are schematic diagrams showing the length of the first protruding portion and the length of the entire protruding portion. In Fig. 4(a) to 4(c), reference numeral 6 denotes the first protruding portion, and reference numeral 7 denotes the second protruding portion. In the example shown in Figure 4(a), a first protruding portion 6 is present at the tip of the protruding portion. The region where the titanium content is 70 mass% or more forms a single mass. In this case, on the upper surface of the protruding portion, the point of the first protruding portion 6 that is closest to the copper circuit portion 3 is identified, and the length L1 is measured. 4(b), the second protruding portion 7 exists on the upper surface of the protruding portion between a part of the first protruding portion 6 and another part of the first protruding portion 6. In this case, the length from the boundary between the part of the first protruding portion 6 connected to the tip of the protruding portion and the second protruding portion 7 on the upper surface of the protruding portion to the tip of the protruding portion is defined as length L1. 4(c), there are a plurality of first protruding portions 6 that are separated from one another on the upper surface of the protruding portion. Second protruding portions 7 exist between the first protruding portions 6. In this case, the length from the boundary between one first protruding portion 6 that is connected to the tip of the protruding portion and the second protruding portion 7 on the upper surface of the protruding portion to the tip of the protruding portion is defined as length L1.

[0017] The joint 5 may contain carbon. The joint 5 containing carbon means that the brazing filler metal contains carbon. By including carbon in the brazing filler metal, the fluidity of the brazing filler metal can be controlled. This allows the brazing filler metal paste to be applied uniformly. When the joint 5 contains carbon, the first protruding portion 6 or the second protruding portion 7 may also contain carbon. The carbon content in the joint 5 is preferably in the range of 0.01% by mass to 2% by mass, and more preferably in the range of 0.05% by mass to 1% by mass. The carbon content in the first protruding portion 6 or the second protruding portion 7 is also preferably in the range of 0% by mass to 1% by mass.

[0018] The inclination angle θ of the side surface of the copper circuit portion 3 is preferably within a range of 30° or more and 70° or less. Fig. 5 is a conceptual diagram illustrating a method for measuring the inclination angle of the side surface of the copper circuit portion. In Fig. 5, reference numeral 3 denotes the copper circuit portion, reference numeral 6 denotes the first protruding portion, and reference numeral 7 denotes the second protruding portion. Point A is the contact point between the end of the copper circuit portion 3 and the brazing material layer 4. Point B is the midpoint in the thickness direction of the side surface of the copper circuit portion 3. Point C is the intersection point of the horizontal line from point A and the vertical line from point B. The inclination angle θ is measured using an SEM photograph of an arbitrary cross section of the ceramic copper circuit board 1. An SEM photograph obtained when the protruding portion is analyzed by SEM-EDX may also be used. First, in the cross-sectional photograph, point A is set as the contact point between the end of the copper circuit portion 3 and the brazing material layer 4, and point B is set as the midpoint in the thickness direction of the side of the copper circuit portion 3. Next, point C is set as the intersection point of the horizontal line from point A and the vertical line from point B. A right triangle is created between the three points ABC. The angle between side BC and side AB is set as the inclination angle θ of the side of the copper circuit portion 3. The inclination angle θ of the side of the copper circuit portion 3 is sometimes simply called the inclination angle θ. By setting the inclination angle θ within the range of 30° to 70°, stress at the joint end can be alleviated. If the inclination angle is less than 30°, the inclined surface of the copper circuit portion 3 becomes longer, which may reduce the area for mounting the semiconductor element. If the inclination angle θ exceeds 70°, the effect of alleviating stress at the joint end may be insufficient. For this reason, the inclination angle θ is preferably within the range of 30° to 70°, and more preferably within the range of 40° to 60°.

[0019] A plurality of copper circuit portions 3 may be bonded to at least one surface of the ceramic substrate 2. The shortest distance between adjacent copper circuit portions 3 may be within a range of 0.2 mm or more and 2 mm or less. FIG. 6 is a schematic diagram showing an example of a semiconductor device according to an embodiment. In FIG. 6, reference numeral 9 denotes a semiconductor element, and reference numeral 10 denotes a semiconductor device. Other reference numerals are the same as those in FIG. 1. P denotes the shortest distance between adjacent copper circuit portions 3. The shortest distance between adjacent copper circuit portions 3 is sometimes called the pitch. When an inclined surface is provided to the copper circuit portion 3, the shortest distance between the side end portions of the copper circuit portion 3 becomes the pitch P. In other words, the distance between the contact points of the end portions of the copper circuit portion 3 and the protruding portions of the brazing material layer becomes the pitch P. A pitch P of 0.2 mm or more and 2 mm or less indicates that the distance between adjacent copper circuit portions 3 is short. For ceramic substrates of the same size, the short distance between adjacent copper circuit portions 3 allows for a larger bonding area between the copper circuit portions 3. This means that the mounting area for semiconductor elements 9 and the like can be increased. Furthermore, for copper circuit portions 3 of the same size, the size of the ceramic copper circuit board 1 can be reduced. This means that the ceramic copper circuit board 1 can be miniaturized without reducing the mounting area for semiconductor elements 9 and the like. In the ceramic copper circuit board 1 according to the embodiment, the pitch P does not have to be in the range of 0.2 mm or more and 2 mm or less. On the other hand, when the pitch P is in the range of 0.2 mm or more and 2 mm or less, the above-described effects can be achieved. Furthermore, when three or more copper circuit portions 3 are bonded, it is preferable that there are two or more locations where the pitch P is in the range of 0.2 mm or more and 2 mm or less. For example, the shortest distance between one copper circuit portion 3 and another copper circuit portion 3 adjacent to that copper circuit portion 3 is in the range of 0.2 mm or more and 2 mm or less. The shortest distance between the other copper circuit portion 3 and the further copper circuit portion 3 adjacent to the other copper circuit portion 3 is within the range of 0.2 mm to 2 mm. When the thickness of the copper plate is D, it is preferable to satisfy the relationship 1≦P / D≦3. Migration can occur not only at the tip of the protruding portion of the brazing material layer but also on the side surface of the copper circuit portion 3. For this reason, it is preferable to set the pitch P according to the thickness D of the copper circuit portion 3.

[0020] The ceramic copper circuit board 1 described above can be applied to a semiconductor device 10 on which a semiconductor element 9 is mounted. As shown in FIG. 6, the semiconductor element 9 is mounted on the copper circuit portion 3. In the example shown in FIG. 6, one semiconductor element 9 is mounted. Multiple semiconductor elements 9 may be mounted on multiple copper circuit portions 3, respectively. A lead frame or wire bonding may be provided as needed. Furthermore, a plating film or mold resin may be provided on the surface of the copper circuit portion 3 as needed. The ceramic copper circuit board 1 according to the embodiment can suppress the occurrence of migration. Furthermore, by setting the pitch P within the range of 0.2 mm to 2 mm or satisfying 1≦P / D≦3, the occurrence of migration can be further suppressed.

[0021] Next, a method for manufacturing the ceramic copper circuit board 1 according to the embodiment will be described. The method for manufacturing the ceramic copper circuit board 1 according to the embodiment is not limited as long as it has the above-mentioned configuration. As an example, the following method can be used to obtain the ceramic copper circuit board 1 with a good yield. First, a ceramic substrate 2 is prepared. Examples of the ceramic substrate 2 include a silicon nitride substrate and an aluminum nitride substrate. A copper plate or a copper alloy plate can be used as a member for forming the copper circuit portion 3 or the copper heat sink 8. The copper plate is preferably oxygen-free copper. As specified in JIS-H-3100, oxygen-free copper is copper with a copper purity of 99.96 wt% or more. JIS-H-3100 (2018) corresponds to ISO1337 and the like. Next, a brazing filler metal is prepared. The brazing filler metal preferably contains 50% by mass or more of Cu, 4% by mass to 30% by mass of Ti, 5% by mass to 45% by mass of one or two elements selected from Sn and In, and 0% by mass to 2% by mass of carbon. Ti may be added as titanium hydride (TiH2). It is effective not to add Ag to the brazing filler metal. A brazing filler metal containing the active metal Ti (including TiH2) is an active metal brazing filler metal. As described below, when the thermal bonding process is performed using a continuous furnace, the Ti content is preferably 2% by mass or more, more preferably 5% by mass or more. In a continuous furnace, the thermal bonding process is performed in a nitrogen atmosphere. Increasing the Ti content in the active metal brazing filler metal ensures that Ti contributes to bonding even if Ti reacts with the nitrogen atmosphere.

[0022] Average particle size D of Cu powder used as raw material for brazing material 50 The average particle size D of the Ti powder or TiH2 powder is preferably 12.0 μm or less, and more preferably 10.0 μm or less. 50The average particle size D of the Sn powder or In powder is preferably 6.0 μm or less, and more preferably 4.0 μm or less. 50 The average particle size D of the carbon powder is preferably 16.0 μm or less, and more preferably 14.0 μm or less. 50 The particle size is preferably 6.0 μm or less, and more preferably 4.0 μm or less. By controlling the particle size of the powder, the reaction of each powder can be made uniform. Although a small amount of Ag may be added to the raw materials, it is preferable not to add it. Average particle size of Cu powder D 50 is the average particle size D of the Sn or In powder 50 As described above, Cu and one or two selected from Sn and In form the base material of the brazing filler metal composition. The melting point of Sn or In is lower than that of Cu. By controlling the particle size of Sn or In, the reaction between the Sn or In powder and the Cu powder can be made uniform. When adding metal elements other than Cu, Ti, Sn and In to the brazing material, the average particle size D of the powder of the metal element 50 is the average particle size D of the Sn or In powder. 50 Preferably, the content of the metal element other than Cu, Ti, Sn, and In is one or more selected from carbon, magnesium, molybdenum, tungsten, rhenium, and cobalt. These elements may be added to the raw material as long as the total content is 10 mass% or less.

[0023] The process of bonding the ceramic substrate 2 and the copper plate is carried out using the above-described brazing filler metal. The brazing filler metal is mixed with an organic substance to prepare a brazing paste. The brazing paste is applied to the surface of the ceramic substrate 2 (or copper plate) to form a brazing paste layer. The copper plate (or ceramic substrate 2) is placed on the brazing paste layer. The laminate of the ceramic substrate, brazing paste, and copper plate is called a pre-bonding laminate.

[0024] Either a batch type or a continuous type may be used for the heat bonding process. The batch type is a method in which the pre-bonding laminate is placed in a storage container and subjected to heat treatment. The continuous type is a method in which the pre-bonding laminate is placed on a belt conveyor and subjected to heat treatment while being moved. The batch type is suitable for bonding processes in a vacuum. The continuous type is suitable for bonding processes in a nitrogen atmosphere. A batch type heat bonding device is sometimes called a batch furnace. A continuous type heat bonding device is sometimes called a continuous furnace. In the batch method, the heating temperature is between 750 and 850°C, and the pressure is 10 -3 It is preferable that the vacuum is equal to or less than Pa. In the continuous method, the heating temperature is preferably within the range of 750°C or more and 950°C or less. In the continuous method, the heat bonding step is performed in a nitrogen atmosphere. A nitrogen atmosphere is an atmosphere with a nitrogen content of 70 vol% or more. The nitrogen atmosphere preferably has a nitrogen content of 70 vol% or more, and more preferably 85 vol% to 100 vol%. In addition to nitrogen gas, examples of the nitrogen atmosphere include an inert gas and the air. When the heat bonding step is performed in a nitrogen atmosphere, the heat bonding step can be performed under various conditions, such as normal pressure, reduced pressure, or increased pressure.

[0025] The thermal bonding process includes a temperature increase process, a temperature holding process, and a temperature decrease process. In the temperature increase process, the temperature is increased from, for example, room temperature to the bonding temperature. In the temperature hold process, the bonding temperature is held. In the temperature decrease process, the temperature is decreased from the bonding temperature to, for example, room temperature. In the continuous heating process, the heating rate is set to 30°C / min or more. There is no particular upper limit to the heating rate, but 100°C / min or less is preferred. If the heating rate is too fast, exceeding 100°C / min, the bonding properties may be reduced. Therefore, the heating rate is preferably 30°C / min or more and 100°C / min or less, and more preferably 40°C / min or more and 70°C / min or less. The bonding temperature is preferably 750°C or higher. The upper limit of the bonding temperature is preferably 1000°C or lower. If the bonding temperature is higher than 1000°C, the bonding temperature approaches the melting point of copper (1085°C), which may cause deformation of the copper plate. For this reason, the bonding temperature is preferably 750°C or higher and 1000°C or lower, and more preferably 800°C or higher and 950°C or lower. In the holding step, the bonding temperature is maintained for 10 minutes or more. The time for which the bonding temperature is maintained is called the heating holding time. The heating holding time is preferably 10 minutes or more and 100 minutes or less. If the heating holding time is less than 10 minutes, there may not be enough time for the brazing material to melt or solidify. If the heating holding time is longer than 100 minutes, there is a possibility that Sn or In will diffuse too much into the copper plate.

[0026] In the temperature-reducing step after the holding step, the temperature-reducing rate is set to 30°C / min or more. There is no particular upper limit to the temperature-reducing rate, but it is preferably 100°C / min or less. If the temperature-reducing rate is too fast, exceeding 100°C / min, the bondability may be reduced. Therefore, the temperature-reducing rate is preferably 30°C / min or more and 100°C / min or less, and more preferably 40°C / min or more and 70°C / min or less. The difference between the heating rate and the temperature decrease rate is preferably 20°C / min or less. In other words, it is preferable to satisfy the following: |Heating rate-Heating rate|≦20°C / min. Heating the brazing paste causes a melting reaction and a solidification reaction. These reactions occur in the heating step and the temperature decrease step. By reducing the difference between the heating rate and the temperature decrease rate, the stresses generated by the melting reaction and the solidification reaction can be homogenized. This makes it possible to suppress defects such as warping. If necessary, the heating and bonding step may be performed while a weight is placed on the bonded body.

[0027] The pre-bonding laminate that has been subjected to the heat bonding process is called a bonded body. The resulting bonded body is then etched to impart a pattern to the copper plate. By imparting a pattern to the copper plate, a copper circuit section 3 is formed. A ceramic copper circuit board 1 equipped with a copper circuit section 3 is obtained. If necessary, scribing may be performed to obtain multiple pieces. Multi-piece production is a method of cutting a large bonded body to obtain smaller bonded bodies. There are also methods of dividing the bonded body or dividing the ceramic copper circuit board. In the etching step, the copper plate is etched to form the copper circuit portion 3 and the copper heat sink plate 8. By etching the copper plate, a portion of the brazing material layer 4 is exposed. Next, a step of etching the brazing material layer 4 is performed. It is preferable that the step of etching the brazing material layer is performed two or more times. If necessary, a chemical polishing step may be combined with the etching of the brazing material layer. By combining chemical polishing with the etching of the brazing material layer, the processing time can be shortened.

[0028] By performing the step of etching the brazing material layer 4 two or more times, it is possible to control the titanium content of the first protruding portion 6 and the second protruding portion 7. In addition, by adjusting the concentration of the etching solution, the treatment time with the etching solution, etc., it is possible to control the length L1 of the first protruding portion 6 and the length L2 of the entire protruding portion. The use of resist allows adjustment of the amount of titanium in the first protrusion portion 6, the length L1 of the first protrusion portion 6, and other factors. The resist is provided in the protrusion portion after etching the copper plate, where the second protrusion portion is formed. Another method is to perform the etching process on the brazing material layer 4 multiple times, shortening the etching time for the second and subsequent etchings compared to the first etching. Another effective method is to etch the side surface of the copper circuit portion 3 after etching the brazing material layer 4. The second protrusion portion 7 can be formed by etching the side surface of the copper circuit portion 3. If necessary, the second protrusion portion 7 may be further etched to form the first protrusion portion 6. By etching the second protrusion portion 7, elements other than titanium (e.g., copper) contained in the second protrusion portion 7 are removed, and the first protrusion portion 6 is formed. A ferric chloride solution can be used as an etching solution for etching the side surfaces of the copper circuit portion 3. A chemical polishing solution may be used instead of the ferric chloride solution. As the chemical polishing solution, a chemical polishing solution containing a mixture of sulfuric acid and hydrogen peroxide is preferably used. If necessary, an etching mask (resist) is applied to the surface of the copper circuit portion 3.

[0029] It is also possible to combine the etching step of the brazing filler metal layer 4 with the etching step for inclining the side surfaces of the copper circuit portion 3. As described above, by not including Ag in the brazing filler metal layer 4, the brazing filler metal layer 4 becomes more easily etched in the etching step of the copper circuit portion 3. A semiconductor device can be obtained by mounting a semiconductor element or the like on the obtained ceramic copper circuit board.

[0030] (Example) (Examples 1 to 6, Comparative Examples 1 and 2) Prepared were the ceramic substrate 2 shown in Table 1 and the copper plate shown in Table 2. Oxygen-free copper plates were used for both copper plates.

[0031] [Table 1]

[0032] [Table 2]

[0033] Next, the brazing filler metals shown in Table 3 were prepared.

[0034] [Table 3]

[0035] A brazing filler paste was prepared using the brazing filler metal, and a pre-bonding laminate shown in Table 4 was produced. Copper plates were placed on both sides of the ceramic substrate 2, respectively.

[0036] [Table 4]

[0037] Next, the pre-bonding stack was subjected to a heat bonding process to produce a bonded body. A continuous furnace was used in the heat bonding process. The heating and holding temperature was set to 850°C or higher and 950°C or lower, and the heating and holding time was set to 30 minutes or higher and 60 minutes or lower. The temperature increase rate and temperature decrease rate were set to 20 to 100°C / min. The difference between the temperature increase rate and the temperature decrease rate was set to 20°C / min or lower. The heat bonding process was carried out in a nitrogen atmosphere. A bonded body was obtained by the heat bonding process. Bonded bodies 1 to 7 were obtained from pre-bonding stacks 1 to 7, respectively. The resulting bonded bodies were subjected to an etching process to produce ceramic copper circuit boards according to the examples and comparative examples. The configuration of each bonded body is as shown in Table 5. The titanium content, the total amount of titanium and nitrogen, length L1, length L2, and inclination angle θ were measured as described above.

[0038] [Table 5]

[0039] As can be seen from Table 5, the ceramic copper circuit board according to the example had a first protruding portion 6 and a second protruding portion 7. In the second protruding portion 7, Cu was contained in the range of 5 to 60 mass% and Sn was contained in the range of 5 to 45 mass%. In contrast, the ceramic copper circuit board according to the comparative example did not have the first protruding portion 6. In the comparative example, only protruding portions with a titanium content of less than 70 mass% were present. In the ceramic copper circuit board according to the example, the titanium content of the first protruding portion 6 was 70 mass% or more, and the titanium content of the second protruding portion 7 was less than 70 mass%. The Cu content C1 (mass%) of the joint 5 was compared with the Cu content C2 (mass%) of the second protruding portion 7. The Ti content C3 (mass%) of the joint 5 was compared with the Ti content C4 (mass%) of the second protruding portion 7. The Ti content (mass%) is the total amount (mass%) of titanium and titanium nitride. The shortest distance (pitch) P between adjacent copper circuit portions 3 and the pitch P / copper circuit thickness D were also measured. The results are shown in Table 6.

[0040] [Table 6]

[0041] A thermal cycle test (TCT test) and a migration test were carried out on the ceramic copper circuit boards according to the examples and comparative examples. The TCT test consisted of one cycle of -50°C x 30 minutes → 25°C x 10 minutes → 155°C x 30 minutes → 25°C x 10 minutes. The silicon nitride substrate was examined for defects after 2000 cycles. The aluminum nitride substrate was examined for defects after 500 cycles. Defects were defined as cracks occurring in the brazing material layer or ceramic substrate. The presence or absence of defects was examined by ultrasonic flaw detection. For each of the examples and comparative examples, tests were conducted on 100 ceramic copper circuit substrates, and the defect occurrence rate (%) was examined. In the migration test, the measurement environment was set to 85°C and humidity to 85%, and a DC voltage of 1000V was applied between the front and back surfaces of the patterned ceramic copper circuit board, which was then left for 2000 hours. After leaving the board, the ceramic copper circuit board was dried at 120°C for 2 hours, and then the insulation resistance between the copper circuit part 3 on the front surface and the copper heat sink 8 on the back surface, as well as the insulation resistance between adjacent copper circuit parts 3 on the front surface, was measured. Bonded bodies with a change in insulation resistance value of 10% or less before and after the test were considered to be good products. Bonded bodies with a change in insulation resistance value of 11% or more were considered to be defective products. The change rate (%) was calculated by the following formula: [(insulation resistance value after test - insulation resistance value before test) / insulation resistance value before test] × 100. The test was conducted on 100 ceramic copper circuit boards each, and the incidence rate (%) of defective products was determined. In the migration test, the insulation resistance value between the copper circuit portion 3 on the front side and the copper heat sink 8 on the back side was measured for 50 ceramic copper circuit boards, and the insulation resistance value between adjacent copper circuit portions 3 on the front side was measured for another 50 ceramic copper circuit boards. When measuring the insulation resistance value between adjacent copper circuit portions 3 on the front side, wire bonding or copper tape was provided between the copper circuit patterns on the front side, as necessary, to adjust these copper circuit patterns to have the same potential. The results are shown in Table 7.

[0042] [Table 7]

[0043] As can be seen from Table 7, the ceramic copper circuit board according to the example exhibited good TCT characteristics. Good results were also obtained in the migration test. The TCT characteristics of the ceramic copper circuit boards according to Comparative Examples 1 and 2 were equivalent to those of the ceramic copper circuit boards according to the Examples. However, the migration characteristics of the ceramic copper circuit boards according to Comparative Examples 1 and 2 were lower than those of the ceramic copper circuit boards according to the Examples. This shows that providing the first protruding portion and the second protruding portion is effective in improving the TCT characteristics while further improving the migration characteristics.

[0044] Implementations may include the following features. (Feature 1) a ceramic substrate; a copper circuit portion bonded to at least one surface of the ceramic substrate via a brazing material layer; A ceramic copper circuit board comprising: the brazing filler metal layer contains Cu, Ti, and one or two selected from Sn and In, The brazing material layer is a bonding portion provided between the ceramic substrate and the copper circuit portion; a first protruding portion provided around the joint and having a titanium content in the range of 70% by mass or more and 100% by mass or less; Ceramic copper circuit boards. (Feature 2) the brazing material layer further includes a second protruding portion provided between the joining portion and the first protruding portion, 2. The ceramic copper circuit board according to Feature 1, wherein the titanium content in the second protruding portion is less than 70 mass %. (Feature 3) the second protruding portion contains 5 mass% or more and 60 mass% or less of Cu and 5 mass% or more and 45 mass% or less of Sn or In, 3. The ceramic copper circuit board according to Feature 2, wherein the total content of titanium and nitrogen in the second protruding portion is within a range of 10% by mass or more and less than 90% by mass. (Feature 4) 4. The ceramic copper circuit board according to any one of Features 2 and 3, wherein the mass ratio of the Cu content in the second protruding portion to the Cu content in the joint portion is 0.7 or less. (Feature 5) 5. The ceramic copper circuit board according to any one of Features 1 to 4, wherein the total content of titanium and nitrogen in the first protruding portion is within the range of 90% by mass or more and 100% by mass or less. (Feature 6) 6. The ceramic copper circuit board according to any one of Features 1 to 5, wherein the total content of titanium and nitrogen in the first protruding portion is within the range of 99% by mass or more and 100% by mass or less. (Feature 7) 7. The ceramic copper circuit board according to any one of Features 1 to 6, wherein, when L1 is a length of the first protruding portion in a direction from the joint portion toward the first protruding portion, and L2 is a length of a portion of the brazing filler metal layer other than the joint portion in the same direction, 0.3≦L1 / L2≦1 is satisfied. (Feature 8) 8. The ceramic copper circuit board according to any one of Features 1 to 7, wherein the brazing material layer further contains carbon. (Feature 9) 9. The ceramic copper circuit board according to any one of Features 1 to 8, wherein the brazing material layer does not contain Ag. (Feature 10) 10. The ceramic copper circuit board according to any one of Features 1 to 9, wherein the inclination angle of the side surface of the copper circuit portion is within a range of 30 degrees or more and 70 degrees or less. (Feature 11) a plurality of adjacent copper circuit portions are bonded to the at least one surface; 11. The ceramic copper circuit board according to any one of Features 1 to 10, wherein the shortest distance between the plurality of copper circuit portions is within a range of 0.2 mm or more and 2 mm or less. (Feature 12) 12. The ceramic copper circuit board according to any one of Features 1 to 11, wherein the ceramic substrate is a silicon nitride substrate. (Feature 13) 13. The ceramic copper circuit board according to any one of Features 1 to 12, wherein the copper circuit portion has a thickness of 0.6 mm or more. (Feature 14) A ceramic copper circuit substrate according to any one of Features 1 to 13; a semiconductor element mounted on the copper circuit portion; A semiconductor device comprising:

[0045] Although several embodiments of the present invention have been described above, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. Furthermore, the above-described embodiments can be implemented in combination with each other. [Explanation of symbols]

[0046] 1...Ceramic copper circuit board 2...Ceramic substrate 3...Copper plate 4...Brazing layer 5…Joint part 6...First protruding part 7...Second protruding part 8...Copper heat sink 9...Semiconductor element 10...Semiconductor device L1: Length of the first protruding part L2: Overall length of the protruding part P: Shortest distance between adjacent copper plates θ: Inclination angle of the copper circuit side Point A: Contact point between the end of the copper circuit and the brazing layer Point B: Midpoint of the thickness of the copper circuit side Point C: Intersection of the horizontal line from point A and the vertical line from point B

Claims

1. a ceramic substrate; a plurality of copper circuit portions each bonded to at least one surface of the ceramic substrate via a brazing material layer; A ceramic copper circuit board comprising: the brazing filler metal layer does not contain Ag, but contains Cu, Ti, and one or two selected from Sn and In, The brazing material layer is a bonding portion provided between the ceramic substrate and the copper circuit portion; a first protruding portion provided around the joint and having a titanium content in the range of 70% by mass or more and 100% by mass or less; Including, A ceramic copper circuit board, wherein when the thickness of the copper circuit portion is D and the shortest distance between adjacent copper circuit portions is P, the thickness D of the copper circuit portion is 0.1 mm or more and includes a portion where 1≦P / D≦3.

2. the brazing material layer further includes a second protruding portion provided between the joining portion and the first protruding portion, The ceramic copper circuit board according to claim 1 , wherein the titanium content in the second protruding portion is less than 70 mass %.

3. the second protruding portion contains 5 mass% or more and 60 mass% or less of Cu and 5 mass% or more and 45 mass% or less of Sn or In, 3. The ceramic copper circuit board according to claim 2, wherein the total content of titanium and nitrogen in the second protruding portion is within a range of 10% by mass or more and less than 90% by mass.

4. 2. The ceramic copper circuit board according to claim 1, wherein the total content of titanium and nitrogen in the first protruding portion is within a range of 90 mass % or more and 100 mass % or less.

5. 2. The ceramic copper circuit board according to claim 1, wherein, when a length of the first protruding portion in a direction from the joint portion toward the first protruding portion is L1 and a length of a portion of the brazing filler metal layer other than the joint portion in the direction is L2, 0.3≦L1 / L2≦1 is satisfied.

6. 5. The ceramic copper circuit board according to claim 4, wherein, when a length of the first protruding portion in a direction from the joint portion toward the first protruding portion is L1 and a length of a portion of the brazing filler metal layer other than the joint portion in the direction is L2, 0.3≦L1 / L2≦1 is satisfied.

7. The ceramic copper circuit board according to claim 1 , wherein the brazing material layer further contains carbon.

8. 2. The ceramic copper circuit board according to claim 1, wherein the inclination angle of the side surface of the copper circuit portion is within a range of 30 degrees or more and 70 degrees or less.

9. 7. The ceramic copper circuit board according to claim 6, wherein the inclination angle of the side surface of the copper circuit portion is within a range of 30 degrees or more and 70 degrees or less.

10. 2. The ceramic copper circuit board according to claim 1, wherein the ceramic substrate is a silicon nitride substrate.

11. 10. The ceramic copper circuit board according to claim 9, wherein the ceramic substrate is a silicon nitride substrate.

12. 2. The ceramic copper circuit board according to claim 1, wherein the thickness D of the copper circuit portion is 0.6 mm or more.

13. The ceramic copper circuit board according to claim 10, wherein the thickness D of the copper circuit portion is 0.6 mm or more.

14. The ceramic copper circuit board according to claim 11, wherein the thickness D of the copper circuit portion is 0.6 mm or more.

15. The ceramic copper circuit board according to any one of claims 1 to 14, a semiconductor element mounted on at least one of the plurality of copper circuit portions; A semiconductor device comprising:

Images