JP2011183798A - Laminated material and method of producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated material in which interfacial peeling between a metallic plate and a ceramic plate is prevented and which enables the production cost thereof to be reduced and has improved heat radiation characteristics. <P>SOLUTION: In the laminated material 1, a Cu plate 2 comprising Cu or Cu alloy is joined with one side surface 4a of the ceramic plate 4, and an Al plate 3 comprising Al or Al alloy is joined with the other side surface 4a of the ceramic plate 4, each by a discharge plasma sintering method. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laminated material and a manufacturing method thereof, and relates to a laminated material used for cooling a semiconductor element such as an LED or a power device, and a manufacturing method thereof.

  In this specification, a material represented by an element symbol means a pure material, but also includes an industrial pure material containing inevitable impurities.

  Further, in this specification and claims, the discharge plasma sintering method is not limited to a method of actually sintering powder, but means a method utilizing the principle of discharge plasma sintering. And

  Further, in this specification and claims, the term “melting point” is intended to mean the solidus temperature in the case of alloys.

  2. Description of the Related Art In recent years, power devices that convert and control electric power have been used for power transmission / transformation, railway vehicle drive control, automobile engine control, inverter drive, air conditioners, solar power inverters, and the like.

  Since this power device generates a large amount of heat during switching, improving the cooling efficiency of the power device is an extremely important issue in order to maintain its function.

  A radiator is used to cool the power device. In a power module including a power device and a radiator, a laminated material including a ceramic plate and a metal plate that are arranged in a laminated manner is disposed between the power device and the radiator. This laminated material is a conductor thermally but has a property of functioning electrically as an insulator, that is, it is used as a thermally conductive insulating substrate.

  As a conventional technique for manufacturing this laminated material, as shown in Japanese Patent Application Laid-Open No. 2004-328012 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2000-256081 (Patent Document 2), a metal plate and a ceramic plate are joined. In this case, a brazing material containing an active metal such as Ag or Ti is arranged at the interface between the metal plate and the ceramic plate (Cu, Al bonding) or an Al-Si alloy brazing material (Al bonding). It is known. As the metal plate, an Al plate or a Cu plate is used.

  Furthermore, in a laminated material in which Al plates are bonded to both surfaces of a ceramic plate, a Ni layer is selectively coated on the surface of the Al plate of the laminated material before mounting the power device by soldering, for example, Ni plating By forming the layer, the solderability is improved. For example, in Japanese Patent Application Laid-Open No. 2009-147123 (Patent Document 3), when a metal part as an electrical wiring or a cooling member is joined to an electrode of a semiconductor element by soldering, metal protection is provided between the solder layer and the electrode. It is disclosed that a Ni plating film is formed as a film.

JP 2004-328012 A JP 2000-256081 A JP 2009-147123 A

  However, in the above method, since a brazing filler metal layer is formed at the bonding interface between the metal plate and the ceramic plate, the bonding reliability of the bonding interface may be impaired. For example, in order to perform bonding between an Al plate and a ceramic plate, a brazing filler metal layer of Al—Si alloy is formed at the bonding interface. However, since the Al—Si alloy is harder than Al of the Al plate, high temperature-low temperature The stress acting on the joint interface accompanying the thermal cycle is extremely large. As a result, material destruction occurs near the interface, and the Al plate and the ceramic plate are separated.

  In addition, in order to form the Ni plating layer on the Al plate surface, there are restrictions such as the roughness of the Al plate surface being small. For this restriction, mechanical and chemical pretreatment is performed on the Al plate surface. As a result, there is a problem that the cost of forming the Ni layer on the surface of the Al plate is increased.

  Furthermore, when it is desired to selectively form a Ni layer partially or only on a certain surface on the surface of the Al plate, a masking process is essential in Ni plating, which increases the manufacturing cost.

  The present invention has been made in view of the above-described technical background, and the object thereof is to prevent interfacial peeling between the metal plate and the ceramic plate, and to reduce the manufacturing cost. An object of the present invention is to provide a laminated material capable of improving heat dissipation characteristics and a method for manufacturing the same.

  The present invention provides the following means.

  [1] A Cu plate made of Cu or Cu alloy is bonded to one side of the ceramic plate, and an Al plate made of Al or Al alloy is bonded to the other side of the ceramic plate by a discharge plasma sintering method. Characteristic laminate material.

  [2] The laminated material according to item 1 above, wherein the Cu plate is directly joined to one surface of the ceramic plate without a brazing filler metal at the joining interface between the ceramic plate and the Cu plate.

  [3] The laminated material according to 1 or 2 above, wherein the Al plate is directly joined to the other one surface of the ceramic plate without a brazing filler metal at the joining interface between the ceramic plate and the Al plate.

[4] Of the preceding items 1 to ₃ , wherein the ceramic plate is made of one material selected from the group consisting of AlN, Al ₂ O ₃ , Si ₃ N ₄ , SiC, Y ₂ O ₃ , CaO, BN and BeO. The laminated material in any one of.

[5] A first laminating step of laminating a ceramic plate and a Cu plate made of Cu or Cu alloy so that the Cu plate is disposed on one side of the ceramic plate;
A first laminate arrangement step of arranging a first laminate of a ceramic plate and a Cu plate between a pair of discharge plasma sintering electrodes;
A first joining step for joining the ceramic plate and the Cu plate of the first laminate by passing a pulse current between the electrodes in a state in which conduction between the two electrodes is ensured;
A laminated body of a ceramic plate and a Cu plate obtained by the first joining step and an Al plate made of Al or an Al alloy are laminated so that the Al plate is disposed on the other surface of the ceramic plate of the joined body. A second laminating step,
A second laminate arrangement step of arranging the second laminate of the joined body and the Al plate between a pair of discharge plasma sintering electrodes;
A second joining step of joining the ceramic plate and the Al plate of the second laminate by passing a pulse current between the electrodes in a state in which conduction between the two electrodes is ensured. A method for producing a laminated material.

[6] In the first joining step, joining is performed at a temperature lower than the melting point of the Cu plate,
6. The method for manufacturing a laminated material according to 5 above, wherein in the second bonding step, bonding is performed at a temperature lower than the melting point of the Al plate.

[7] In the first bonding step, the bonding is performed while pressing the first stacked body at 10 to 100 MPa from both sides in the stacking direction,
7. The method for producing a laminated material according to 5 or 6 above, wherein in the second joining step, the joining is performed while pressing the second laminated body at 10 to 100 MPa from both sides in the laminating direction.

[8] In the first bonding step, bonding is performed in an inert gas atmosphere or a vacuum atmosphere,
8. The method for manufacturing a laminated material according to any one of 5 to 7 above, wherein in the second bonding step, bonding is performed in an inert gas atmosphere or a vacuum atmosphere.

  According to the laminated material of [1] to [3], since the Cu plate and the Al plate are respectively joined to the predetermined surfaces of the ceramic plate by the discharge plasma sintering method, the ceramic plate and the metal plate (that is, the Cu plate, It is not necessary to arrange a brazing material containing an active metal such as Ag or Ti at the bonding interface with the Al plate), that is, direct bonding is possible. For this reason, interfacial delamination between the ceramic plate and the metal plate due to the cooling / heating cycle is suppressed, thereby improving the bonding reliability. Furthermore, since no brazing material is used, the manufacturing cost of the laminated material can be reduced.

  Furthermore, according to the laminated material of [1] to [3], since the Cu plate is bonded to one side of the ceramic plate, the heat dissipation characteristics are improved and the Cu plate can be directly soldered. In addition, the Ni plating process for improving the solderability, which is essential for the Al plate, is not required. Thereby, the manufacturing cost can be further reduced. Moreover, since the Al plate is bonded to the other surface of the ceramic plate, for example, a heat radiating member such as a heat sink made of Al or Al alloy can be attached to the Al plate by metal bonding such as brazing. As a result, a power device cooling member (base for power module) that is lightweight and has improved heat dissipation characteristics can be obtained.

According to the laminated material of [4], the ceramic plate is made of one material selected from the group consisting of AlN, Al ₂ O ₃ , Si ₃ N ₄ , SiC, Y ₂ O ₃ , CaO, BN and BeO. Therefore, a Cu plate can be used as a wiring layer, and a ceramic plate can be used as an electrical insulation layer having excellent electrical insulation performance. Therefore, for example, a power module base can be formed as a semiconductor module base by brazing a heat radiating member such as a heat sink made of Al or an Al alloy to the surface of the Al plate of the laminated material. And a power module can be manufactured as a semiconductor module by mounting, for example, a power device as a semiconductor element on the Cu plate of the base laminate. According to this power module, the Cu plate, the ceramic plate, and the Al plate are only arranged between the power device and the heat radiating member, so the heat conduction path from the power device to the heat radiating member is shortened. The heat dissipation performance of the heat generated from the device is improved. Moreover, it is not necessary to interpose a brazing material having low thermal conductivity between the metal plate (ie, Cu plate, Al plate) and the ceramic plate, and the thermal conductivity between the two metal plates and the ceramic plate is excellent. Become a thing.

  According to the method for producing a laminated material of [5], the laminated materials of [1] to [4] can be produced without using a brazing material. Therefore, a ceramic and a metal plate (that is, a Cu plate) due to temperature change. The bonding reliability of the bonding interface with the Al plate can be improved. Furthermore, since no brazing material is used, the laminated material can be manufactured at low cost.

  According to the method for manufacturing a laminated material of [6], it is possible to prevent deformation due to partial melting of the Cu plate at the time of joining in the first joining step, and Al at the time of joining in the second joining step. Deformation due to partial melting of the plate can be prevented.

  Here, in the first bonding step, the bonding temperature may be set within a range of 933 to 1073 ° C. (preferably 950 to 1000 ° C.). In the second bonding step, the bonding temperature may be set in the range of 510 to 650 ° C. (preferably 520 to 600 ° C.).

  According to the method for manufacturing a laminated material of [7], it is possible to effectively prevent the occurrence of a bonding defect between the Cu plate and the ceramic plate, and the bonding defect between the Al plate and the ceramic plate. Can be effectively prevented.

  According to the method for manufacturing a laminated material of [8], it is possible to effectively prevent the occurrence of a bonding defect between the Cu plate and the ceramic plate, and the bonding defect between the Al plate and the ceramic plate. Can be effectively prevented.

FIG. 1 is a vertical sectional view showing a laminated material according to an embodiment of the present invention. FIG. 2 is a vertical sectional view showing a first joining step in the manufacturing process of the laminated material. FIG. 3 is a vertical cross-sectional view showing the joined body obtained by the first joining process. FIG. 4 is a vertical sectional view showing a second joining step in the manufacturing process of the laminated material. FIG. 5 is a vertical sectional view showing the laminated material of Comparative Example 1. FIG. 6 is a vertical sectional view showing the laminated material of Comparative Example 2.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the following description, the top and bottom of each drawing is referred to as the top and bottom. Moreover, the same code | symbol is attached | subjected to the same part and the same thing through all drawings, and the overlapping description is abbreviate | omitted.
Embodiment 1
1-4 is a figure for demonstrating the laminated material of one Embodiment of this invention, and its manufacturing method. This embodiment shows a case where the laminated material can be used as an insulating substrate on which a semiconductor element (eg, a power device) is mounted.

  As shown in FIG. 1, the laminated material (1) of this embodiment includes at least one ceramic plate (4) and at least one Cu or Cu alloy disposed on one side of the ceramic plate (4). The Cu plate (2) made of the above and the Al plate (3) made of at least one Al or Al alloy disposed on the other side of the ceramic plate (4) are laminated.

  In this laminated material (1), the ceramic plate (4) is arranged horizontally. The Cu plate (2) is disposed adjacent to the ceramic plate (4) on the upper surface (4a) of the ceramic plate (4). The Al plate (3) is disposed adjacent to the ceramic plate (4) on the lower surface (4a) of the ceramic plate (4). The adjacent plates (2, 4), (4, 3) are joined together by the spark plasma sintering method. Therefore, the Cu plate (2) is arranged on the uppermost outer side of the laminate (1), and the ceramic plate (4) is arranged between the Cu plate (2) and the Al plate (3), The Al plate (3) is disposed on the outermost side below the laminated material (1). Since the ceramic plate (4) and the Cu plate (2) are joined by the discharge plasma sintering method, the Cu plate (2) is bonded to the upper surface (4a) of the ceramic plate (4), the ceramic plate (4) and the Cu plate (4). It is joined directly to the plate (2) without a brazing material. Similarly, since the ceramic plate (4) and the Al plate (3) are joined by the discharge plasma sintering method, the Al plate (3) is attached to the lower surface (4a) of the ceramic plate (4). ) And the Al plate (3) without a brazing material, that is, directly joined.

  Here, one ceramic plate (4) is laminated so as to be positioned between one Cu plate (2) and one Al plate (3), and adjacent Cu plates (2). And the ceramic plate (4), and the ceramic plate (4) and the Al plate (3) are sequentially (stepwise) joined by the discharge plasma sintering method. Further, the laminated material (1) has a three-layer structure.

  The flatness of the upper and lower surfaces of the laminated material (1), that is, the upper surface of the Cu plate (2) and the lower surface of the Al plate (3) is 100 μm or less, respectively.

  The Cu plate (2) is made of Cu or a Cu alloy as described above. The Al plate (3) is made of Al or an Al alloy as described above. Incidentally, the melting points of the materials constituting the Cu plate (2) and the Al plate (3) are Cu: 1083 ° C. and Al: 660 ° C., respectively, and the melting points of the Cu alloy and the Al alloy are usually Cu and Lower than the melting point of Al.

  The thicknesses of the Cu plate (2) and the Al plate (3) are preferably 3 mm or less (preferably 200 μm or more). The Cu plate (2) and the Al plate (3) are formed by a known appropriate method.

The ceramic plate (4) is made of one kind of electrically insulating material selected from the group consisting of AlN, Al ₂ O ₃ , Si ₃ N ₄ , SiC, Y ₂ O ₃ , CaO, BN and BeO. The thickness of the ceramic plate (4) is preferably 1 mm or less (preferably 300 μm or more). The ceramic plate (4) is made of, for example, powder of one material selected from the group consisting of AlN, Al ₂ O ₃ , Si ₃ N ₄ , SiC, Y ₂ O ₃ , CaO, BN, and BeO. It is formed by sintering by a discharge plasma sintering method using a sintering aid. The ceramic plate (4) is heated using powder of one material selected from the group consisting of AlN, Al ₂ O ₃ , Si ₃ N ₄ , SiC, Y ₂ O ₃ , CaO, BN and BeO. It may be formed by hot isostatic pressing (HIP).

Here, the melting point or decomposition point of each ceramic material is AlN: 2200 ° C., Al ₂ O ₃ : 2050 ° C., Si ₃ N ₄ : 1900 ° C., SiC: 2000 ° C., Y ₂ O ₃ : 2400 ° C., CaO: 2570. ° C, BN: 3000 ° C, BeO: 2570 ° C, which are higher than the melting points of the materials constituting the Cu plate (2) and the Al plate (3).

  The shapes of the Cu plate (2), the Al plate (3), and the ceramic plate (4) are, for example, quadrangular in plan view. However, in the present invention, the Cu plate (2), the Al plate (3), and the ceramic plate (4) are not limited to a quadrangular shape in plan view, and other than that, a polygonal shape, a circular shape, an elliptical shape It may be a shape or a shape surrounded by an arbitrary curve. Further, these plates (2), (3), and (4) may have the same shape, similar shapes, or irregular shapes.

  The outer dimensions of the upper surface (4a) and the lower surface (4a) of the ceramic plate (4) are slightly larger than the outer dimensions of the lower surface of the Cu plate (2) and the upper surface of the Al plate (3), respectively.

  Then, on the inner side of the outer peripheral edge (4z) of the surface of the ceramic plate (4) joined to the Cu plate (2) (that is, the upper surface (4a) of the ceramic plate (4)), the Cu plate (2) The bonding surface (2a) with the ceramic plate (4) (that is, the lower surface of the Cu plate (2)) is located. Further, on the inner side of the outer peripheral edge (4z) of the surface of the ceramic plate (4) joined to the Al plate (3) (that is, the lower surface (4a) of the ceramic plate (4)), the Al plate (3) The bonding surface (3a) with the ceramic plate (4) (that is, the lower surface of the Al plate (3)) is located.

  In the laminated material (1) of the present embodiment, the surface of the ceramic plate (4) that is joined to the Cu plate (2) is the upper surface (4a) of the ceramic plate (4). The surface of the ceramic plate (4) on the side joined to the Al plate (3) is the lower surface (4a) of the ceramic plate (4). Further, the upper surface (4a) of the ceramic plate (4) is also a surface adjacent to the Cu plate (2), and the lower surface (4a) of the ceramic plate (4) is also a surface adjacent to the Al plate (3). Further, the bonding surface (2a) between the Cu plate (2) and the ceramic plate (4) is the lower surface of the Cu plate (2). The joint surface (3a) between the Al plate (3) and the ceramic plate (4) is the upper surface of the Al plate (3).

  As shown in FIG. 1, the distance d from the outer peripheral edge (4z) of the upper surface (4a) of the ceramic plate (4) to the bonding surface (2a) of the Cu plate (2) is preferably 0.5 mm or more. Similarly, the distance d from the outer peripheral edge (4z) of the lower surface (4a) of the ceramic plate (4) to the joining surface (3a) of the Al plate (3) is preferably 0.5 mm or more. By doing so, it is possible to reliably prevent leakage from the outer peripheral edge of the Cu plate (2). The upper limit of the distance d is not particularly limited, and is usually about 2.0 mm.

  Although illustration is omitted, one application example (use example) of the laminated material (1) is given below.

  The laminated material (1) is used for, for example, a substrate or a cooling member on which semiconductor elements such as MOSFETs, IGBTs, and diodes used in electric power converters for electric motors such as electric railway vehicles are mounted. As semiconductor elements, power devices used in power transmission / transformation control devices, railway vehicle drive control devices, automobile engine control devices, inverter drive devices, home air conditioner control devices, solar power generation control devices, etc. operate. The heat generation at the time of switching at the time of switching is preferably mentioned. A radiator is used to cool the power device. In a power module including a power device and a radiator, generally, a laminated material having a property that functions thermally as an insulator but electrically functions as an insulator is disposed between the power device and the radiator. Has been. As this laminated material, the laminated material (1) of the present embodiment is preferably used. Specifically, since the laminated material (1) includes the Cu plate (2), it is suitably used as a thermally conductive insulating substrate having a wiring layer that can be directly soldered. Furthermore, since the laminated material (1) has the Cu plate (2) adjacent to the semiconductor element, the heat generated from the semiconductor element can be efficiently diffused, and therefore, the insulating substrate having a wiring layer with good heat dissipation characteristics Also used as Furthermore, since the laminated material (1) includes the Al plate (3) on the side opposite to the side on which the Cu plate (2) is disposed, a lightweight and heat radiating heat sink made of Al or Al alloy is brazed. It can be attached to the Al plate (3) by metallic bonding. Thereby, the heat radiating member which can transmit the heat | fever emitted from a semiconductor element to a heat sink efficiently and can radiate | emit can be comprised.

  Next, the manufacturing method of a laminated material (1) is demonstrated with reference to FIGS.

That is, a Cu plate (2) made of Cu or Cu alloy and manufactured by a general manufacturing method, an Al plate (3) made of Al or Al alloy and manufactured by a general manufacturing method, AlN, Ceramic plate made of one material selected from the group consisting of Al ₂ O ₃ , Si ₃ N ₄ , SiC, Y ₂ O ₃ , CaO, BN and BeO and manufactured by a general manufacturing method (4) And prepare.

  Here, the surface roughness of the Cu plate (2) and the Al plate (3) is preferably 1.0 μm or less in terms of arithmetic average roughness (Ra), and the thickness is preferably 3 mm or less. The surface roughness of the ceramic plate (4) is preferably 1.5 μm or less in arithmetic mean roughness (Ra), and the thickness is preferably 1 mm or less.

  Next, in the cylindrical graphite sintering die (10) having electrical conductivity of the discharge plasma sintering apparatus, the ceramic plate (4) and the Cu plate (2) are placed on the upper surface of the ceramic plate (4) (4a The Cu plate (2) is disposed adjacent to the ceramic plate (4) and on the inner side of the outer peripheral edge (4z) of the upper surface (4a) of the ceramic plate (4). ) Are arranged so that the planned joining surface (2b) consisting of the lower surface of the substrate is positioned. Thus, a 1st laminated body (60) is formed by laminating | stacking a ceramic board (4) and Cu board (2). Adjacent plates (2, 4) are in surface contact. The vertical height of the die (10) is higher than the total thickness of the Cu plate (2) and the ceramic plate (4). It protrudes outward in the vertical direction from the ceramic plate (4). Next, graphite punches (11) and (12) are arranged on both upper and lower sides of the first laminate (60) made of the Cu plate (2) and the ceramic plate (4) in the die (10), and the upper punch ( The electrodes (13) and (14) are brought into electrical contact with the upper surface of 11) and the lower surface of the lower punch (12), respectively. In this state, conduction between the electrodes (13) and (14) is ensured by the punches (11) and (12) and the die (10).

  In the present invention, the stacking order of the first stacked body (60) may be reversed as long as the stacked structure is maintained. Further, a plurality of the first laminated bodies (60) may be arranged so as to be stacked in the vertical direction in the die (10). In this case, it is desirable to install a plate material made of a material equivalent to the die (10) as a spacer between the adjacent first stacked bodies (60). Furthermore, between the electrodes (13) and (14), a plurality of groups consisting of a die (10) including one or more first laminated bodies (60) and punches (11) (12) are arranged in parallel. They may be arranged side by side.

  Next, in a vacuum atmosphere of 1 to 10 Pa, or in an inert gas atmosphere such as nitrogen or argon, the first laminate (60) is moved by the upper and lower punches (11) (12) or both electrodes (13) (14). A temperature lower than the melting point of the Cu plate (2) by applying a pulse current between both electrodes (13) and (14) while applying pressure from both the top and bottom directions, that is, from both sides of the first laminate (60) in the stacking direction. In addition, the temperature is raised and held at the temperature for a predetermined time, thereby joining the ceramic plate (4) and the Cu plate (2). This process is referred to as a “first bonding process” by a discharge plasma sintering method. In this way, the joined body (61) having the two-layer structure shown in FIG. 3 is obtained.

  When a plurality of first laminated bodies (60) are arranged so as to be stacked in the die (10), a plurality of joined bodies (61) are manufactured simultaneously. When a plurality of groups consisting of a die (10) including the first laminate (60) and both punches (11) (12) are arranged in parallel between the electrodes (13) (14) A plurality of joined bodies (61) are manufactured simultaneously.

  The joining conditions in the first joining step described above vary depending on the materials and dimensions of the Cu plate (2) and the ceramic plate (4). It is 933-1073 degreeC (preferably 950-1000 degreeC), and joining temperature holding time is 1-30 minutes.

  In the first joined body (61) shown in FIG. 3, the Cu plate (2) is placed on the upper surface (4a) of the ceramic plate (4) at the joining interface between the ceramic plate (4) and the Cu plate (2). It is joined directly without the brazing material. Furthermore, the joint surface (2a) with the ceramic surface (4) of the Cu plate (2) is located inside the outer peripheral edge (4z) of the upper surface (4a) of the ceramic plate (4).

  Next, as shown in FIG. 4, the joined body (61) and the Al plate (3) are placed in the graphite sintering die (10) of the discharge plasma sintering apparatus, and the joined body (61) ceramic plate ( The upper surface of the Al plate (3) so that the Al plate (3) is disposed on the lower surface (4a) of 4) and inside the outer peripheral edge (4z) of the lower surface (4a) of the ceramic plate (4) Laminated and arranged so that the planned joining surface (3b) is located. In this way, the second laminate (62) is formed by laminating the joined body (61) and the Al plate (3). Adjacent plates (61, 3) are in surface contact. The height in the vertical direction of the die (10) is higher than the total thickness of the joined body (61) and the Al plate (3), and the upper and lower end portions of the die (10) are connected to the joined body (61). It protrudes outward in the vertical direction from the Cu plate (2) and the Al plate (3). Next, graphite punches (11) and (12) are arranged on the upper and lower sides of the second laminate (62) made of the joined body (61) and the Al plate (3) in the die (10), and the upper punch (11 The electrodes (13) and (14) are brought into electrical contact with the upper surface of) and the lower surface of the lower punch (12), respectively. In this state, conduction between the electrodes (13) and (14) is ensured by the punches (11) and (12) and the die (10).

  In the present invention, the stacking order of the second stacked body (62) may be reversed as long as the stacked structure is maintained. Further, a plurality of second stacked bodies (62) may be arranged so as to be stacked in the vertical direction in the die (10). In this case, it is desirable to install a plate material made of a material equivalent to the die (10) as a spacer between the adjacent second stacked bodies (62). Furthermore, between the electrodes (13) and (14), a plurality of groups consisting of a die (10) including one or more second laminated bodies (62) and punches (11) (12) are arranged in parallel. They may be arranged side by side.

  Next, in a vacuum atmosphere of 1 to 10 Pa, or in an inert gas atmosphere such as nitrogen or argon, the second laminated body (62) is moved by the upper and lower punches (11) (12) or both electrodes (13) (14). A temperature lower than the melting point of the Al plate (3) by applying a pulse current between the electrodes (13) and (14) while applying pressure from both sides in the vertical direction, that is, from both sides of the second laminate (62). In addition, the temperature is raised and held at the temperature for a predetermined time, thereby joining the ceramic plate (4) and the Al plate (3) of the second laminate (62). This process is referred to as a “second bonding process” by a discharge plasma sintering method. In this way, the desired laminated material (1) shown in FIG. 1 is manufactured.

  When a plurality of second laminated bodies (62) are arranged so as to be stacked in the die (10), a plurality of laminated materials (1) are manufactured simultaneously. When a plurality of groups of dies (10) including the second laminate (62) and punches (11) (12) are arranged in parallel between the electrodes (13) (14) A plurality of laminated materials (1) are manufactured simultaneously.

  The joining conditions in the second joining step described above vary depending on the materials and dimensions of the ceramic plate (4) and the Al plate (3) of the joined body (61). The bonding temperature is 10 to 100 MPa, the bonding temperature is 510 to 650 ° C. (preferably 520 to 600 ° C.), and the bonding temperature holding time is 1 to 30 min.

  Here, since the melting point of the Al plate (3) is generally lower than the melting point of the Cu plate (2), the bonding of the Al plate (3) and the ceramic plate (4) as in this embodiment is performed using Cu (2). This is performed after joining the ceramic plate (4) to avoid melting the Al plate (3) when the Cu plate (2) and the ceramic plate (4) are joined. Thus, it is possible to reliably obtain a desired laminated material (1) having a three-layer structure (Cu / ceramic / Al) having a good bonding state.

  The mechanism by which the Cu plate (2) and Al plate (3) and the ceramic plate (4) are joined is not clear, but is considered as follows.

  That is, when a metal plate (ie, Cu plate (2), Al plate (3)) and ceramic plate (4) are pressed from both sides in the stacking direction, the metal plate yields to form the metal plate. The material to be entered enters a minute recess on the surface of the ceramic plate (4), and the contact area between the metal plate and the ceramic plate (4) increases. In this state, when a pulse current is applied between both electrodes (13) and (14) of the spark plasma sintering apparatus and the metal plate is heated, the metal plate softens and the contact area between the metal plate and the ceramic plate (4) Becomes even larger. At this time, when discharge plasma is emitted in the vicinity of the contact portion between the surface of the metal plate and the surface of the ceramic plate (4), the oxide film on the surface of the metal plate is destroyed and removed, so that the active surface is exposed. When the active surface of the metal plate comes into contact with the surface of the ceramic plate (4), it is considered that the metal plate and the ceramic plate (4) are joined by material diffusion.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be variously modified.

  Hereinafter, specific examples of the laminated material according to the present invention will be described together with comparative examples.

<Example 1>
The laminated material of this example is the laminated material (1) of the above embodiment.

  One Cu plate (2) made of Cu with a purity of 99.5% by mass and 32 mm long, 26 mm wide and 0.6 mm thick, and made of Al with a purity of 99.99 mass% 32 mm long, 26 mm wide, thickness One 0.6 m Al plate (3) and one AlN ceramic plate (4) 34 mm long, 28 mm wide and 0.635 mm thick were prepared. And the degreasing | defatting process was performed using the organic solvent on the surface of Cu board (2), Al board (3), and ceramic board (4). In addition, the removal process of an oxide film is not given. The surface roughness of both surfaces of the Cu plate (2) is Ra 1.1 μmm in terms of arithmetic average roughness, the surface roughness of both surfaces of the Al plate (3) is Ra 0.9 μm in terms of arithmetic average roughness, and the ceramic plate (4). The surface roughness of both surfaces was Ra 0.8 μm in terms of arithmetic average roughness. Ra was measured according to JIS (Japanese Industrial Standards) B 0601: 1994.

  Next, as shown in FIG. 2, the ceramic plate (4) and the Cu plate (2) are placed in the sintering die (10), and the Cu plate (2) is placed on the upper surface (4a) of the ceramic plate (4). Are arranged adjacent to the ceramic plate (4), and are to be joined from the lower surface of the Cu plate (2) inside the outer peripheral edge (4z) of the upper surface (4a) of the ceramic plate (4). The layers were stacked so that (2b) was positioned. At this time, these plates (4) and (2) were arranged so that the center of gravity of the ceramic plate (4) and the center of gravity of the Cu plate (2) coincided with each other in the thickness direction. Then, graphite punches (11) and (12) are arranged on both upper and lower sides of the first laminate (60) made of the Cu plate (2) and the ceramic plate (4) in the die (10), and the upper punch ( The electrodes (13) and (14) were brought into electrical contact with the upper surface of 11) and the lower surface of the lower punch (12), respectively. In this state, conduction between the electrodes (13) and (14) is ensured by the punches (11) and (12) and the die (10).

  Next, in a vacuum atmosphere of 1 to 10 Pa, the first laminated body (60) is pressed between the upper and lower punches (11) and (12) at a pressure of 20 MPa from the upper and lower sides, and between the electrodes (13) and (14). The first laminated body (60) is heated from room temperature to 950 ° C. over 25 minutes by energizing a pulse current of a maximum of 2500 A, and held at 950 ° C. for 5 minutes, whereby the Cu plate (2) and the ceramic plate (4) was joined [first joining step]. Next, the energization between the electrodes (13) and (14) was stopped, and then cooled to produce the joined body (61) having the two-layer structure shown in FIG.

  Next, as shown in FIG. 4, the joined body (61) and the Al plate are placed in the sintering die (10), and the lower surface (4a) of the ceramic plate (4) of the joined body (61) is made of Al. The Al plate (3) is to be joined so that the plate (3) is disposed adjacent to the ceramic plate (4) and inside the outer peripheral edge (4z) of the lower surface (4a) of the ceramic plate (4). The layers (3b) were laminated so as to be positioned. Then, graphite punches (11) and (12) are arranged on both upper and lower sides of the second laminate (62) made of the joined body (61) and the Al plate (3) in the die (10), and the upper punch ( The electrodes (13) and (14) were brought into electrical contact with the upper surface of 11) and the lower surface of the lower punch (12), respectively. In this state, conduction between the electrodes (13) and (14) is ensured by the punches (11) and (12) and the die (10).

  Next, in a vacuum atmosphere of 1 to 10 Pa, the second laminate (62) is pressed between the upper and lower punches (11) and (12) at a pressure of 20 MPa from the upper and lower sides, and between the electrodes (13) and (14). The second laminate (62) is heated from room temperature to 550 ° C. over 10 minutes by passing a pulse current of 1500 A at the maximum and held at 550 ° C. for 5 minutes, whereby the second laminate (62) The ceramic plate (4) and the Al plate (3) were joined [second joining step]. Subsequently, the energization between the electrodes (13) and (14) was stopped, and then cooled to produce the desired three-layered laminate (1) shown in FIG.

  In the manufactured laminated material (1), the joining of the Cu plate (2) and the ceramic plate (4) and the joining of the Al plate (3) and the ceramic plate (4) are both performed by the discharge plasma sintering method. Therefore, it was not necessary to use a brazing material, so that the manufacturing cost of the laminated material (1) could be reduced.

  Further, the flatness of both surfaces of the laminate (1) was measured and found to be 70 μm. Furthermore, in order to confirm the bonding state between the Cu plate (2) and the ceramic plate (4) and the bonding state between the Al plate (3) and the ceramic plate (4) in the laminated material (1), the lamination material (1) When the cross section was observed, no defects were found at the bonding interface, and good bonding was performed.

  In addition, the laminated material (1) was subjected to a cooling / heating cycle test under the test conditions of −40 ° C. to 125 ° C. and 1000 cycles. Then, the presence or absence of peeling at the bonding interface between the Cu plate (2) and the ceramic plate (4) and the bonding interface between the Al plate (3) and the ceramic plate (4) was examined. The results are shown in the “Peel” column in Table 1. As shown in the same column, no peeling occurred at each bonding interface.

  Also, an Al water-cooled sheet sink was brazed to the surface of the Al plate (3) of the laminate (1), and then a semiconductor element was soldered to the surface of the Cu plate (2) of the laminate (1). The thermal resistance was examined as the heat dissipation performance of the laminate (1). The results are shown in the “Heat dissipation performance” column of Table 1. As shown in the same column, a Cu plate (2) whose thermal conductivity is about twice as high as that of Al is arranged directly under the semiconductor element, so that the heat dissipation performance is high and the heat generated from the semiconductor element is efficiently radiated. I was able to. Further, in this laminated material (1), since it is not necessary to perform Ni plating before soldering the semiconductor element, the manufacturing cost of the laminated material (1) can be further reduced. Further, when the sheet sink was brazed to the surface of the Al plate (3) of the laminated material (1), the laminated material (1) and the heat sink could be joined metallically.

<Example 2>
A laminated material (1) having a three-layer structure was formed in the same manner as in Example 1 except that the pulse current was passed between the electrodes (13) and (14) in an inert gas atmosphere made of nitrogen. Manufactured.

  It was 72 micrometers when the flatness of both surfaces of the manufactured laminated material (1) was measured. Furthermore, in order to confirm the bonding state between the Cu plate (2) and the ceramic plate (4) and the bonding state between the Al plate (3) and the ceramic plate (4) in the laminated material (1), the lamination material (1) When the cross section was observed, no defects were found at the bonding interface, and good bonding was performed.

  Moreover, about the laminated material (1), the thermal cycle test was done on the same test conditions as the thermal cycle test of Example 1. FIG. Then, the presence or absence of peeling at the bonding interface between the Cu plate (2) and the ceramic plate (4) and the bonding interface between the Al plate (3) and the ceramic plate (4) was examined. The results are shown in the “Peel” column in Table 1. As shown in the same column, no peeling occurred at each bonding interface.

  Also, an Al water-cooled sheet sink was brazed to the surface of the Al plate (3) of the laminate (1), and then a semiconductor element was soldered to the surface of the Cu plate (2) of the laminate (1). And the heat dissipation performance (thermal resistance) of the laminated material (1) was examined. The results are shown in the “Heat dissipation performance” column of Table 1. As shown in the same column, the laminated material (1) of Example 2 also had high heat dissipation performance, and was able to efficiently dissipate heat generated from the semiconductor element. Further, in this laminated material (1), since it is not necessary to perform Ni plating before soldering the semiconductor element, the manufacturing cost of the laminated material (1) can be further reduced. Further, when the sheet sink was brazed to the surface of the Al plate (3) of the laminated material (1), the laminated material (1) and the heat sink could be joined metallically.

<Comparative Example 1>
A laminated material (101A) having a three-layer structure shown in FIG. 5 was produced as follows.

  Two Al plates (103) and one ceramic plate (104) made of the same material and shape as the Al plate (3) and ceramic plate (4) used in Example 1 were prepared. That is, the Al plate (103) is made of Al having a purity of 99.99% by mass, and the shape thereof is 32 mm in length, 26 mm in width, and 0.6 mm in thickness. The ceramic plate (104) is made of AlN, and its shape is 34 mm long, 28 mm wide, and 0.635 mm thick. Then, the Al plate (103) is brazed to both surfaces of the ceramic plate (104) with a brazing material made of an Al-Si alloy interposed between each Al plate (103) and the ceramic plate (104), Thereby, the laminated material (101A) shown in FIG. 5 was manufactured.

  The manufactured laminate (101A) was subjected to a thermal cycle test under the same test conditions as the thermal cycle test of Example 1. Then, the presence or absence of peeling at the bonding interface between each Al plate (103) and the ceramic plate (104) was examined. The results are shown in the “Peel” column in Table 1. As shown in the same column, peeling occurred at each bonding interface.

  Also, an Al water-cooled sheet sink is brazed to the surface of one Al plate (103) of the laminated material (101A), and then Ni plating is applied to the surface of the other Al plate (103) of the laminated material (101A). Then, a Ni plating layer was formed, and then a semiconductor element was soldered to the surface of the Ni plating layer. And the heat dissipation performance (thermal resistance) of the laminated material (101A) was examined. The results are shown in the “Heat dissipation performance” column of Table 1. As shown in the same column, the heat dissipation performance of the laminate (101A) was worse than that of the laminates (1) of Examples 1 and 2. Further, in this laminated material (101A), since it was necessary to perform Ni plating before soldering the semiconductor element, the manufacturing cost of the laminated material (101A) was increased.

<Comparative example 2>
A laminate (101B) having a three-layer structure shown in FIG. 6 was produced as follows.

  Two Cu plates (102) and one ceramic plate (104) made of the same material and shape as the Cu plate (2) and ceramic plate (4) used in Example 1 were prepared. That is, the Cu plate (102) is made of Cu having a purity of 99.5% by mass, and the shape thereof is 32 mm in length, 26 mm in width, and 0.6 mm in thickness. The ceramic plate (104) is made of AlN, and its shape is 34 mm long, 28 mm wide, and 0.635 mm thick. Then, a Cu plate (102) is provided on both sides of the ceramic plate (104), and a material containing an active metal composed of Ti and Ag interposed between each Cu plate (102) and the ceramic plate (104). The laminated material (101B) shown in FIG. 6 was manufactured by brazing.

  The manufactured laminate (101B) was subjected to a thermal cycle test under the same test conditions as the thermal cycle test of Example 1. Then, the presence or absence of peeling at the joint interface between each Cu plate (102) and the ceramic plate (104) was examined. The results are shown in the “Peel” column in Table 1. As shown in the same column, peeling occurred at each bonding interface.

  Also, a water-cooled sheet sink made of Al is adhered to the surface of one Cu plate (102) of the laminated material (101B) with heat conductive grease, and then the semiconductor is formed on the surface of the other Cu plate (102) of the laminated material (101B). The element was soldered. And the heat dissipation performance (thermal resistance) of the laminated material (101B) was examined. The results are shown in the “Heat dissipation performance” column of Table 1. As shown in the same column, the heat dissipation performance of the laminated material (101B) was worse than that of the laminated materials (1) of Examples 1 and 2.

  The laminated material according to the present invention is suitably used for cooling a semiconductor element such as a power device.

(1): Laminated material
(2): Cu plate
(3): Al plate
(4): Ceramic plate

Claims (8)

  A Cu plate made of Cu or Cu alloy is bonded to one side of the ceramic plate, and an Al plate made of Al or Al alloy is bonded to the other side of the ceramic plate by a discharge plasma sintering method, respectively. Laminated material.   The laminated material according to claim 1, wherein a Cu plate is directly joined to one side of the ceramic plate without a brazing material at a joint interface between the ceramic plate and the Cu plate.   The laminated material according to claim 1 or 2, wherein an Al plate is directly bonded to the other surface of the ceramic plate at a bonding interface between the ceramic plate and the Al plate without using a brazing material. Ceramic _{plate, AlN, Al 2 O 3,} Si 3 N 4, SiC, Y 2 O 3, CaO, any of the preceding claims consisting of one material selected from the group consisting of BN and BeO The laminated material of crab. A first laminating step of laminating a ceramic plate and a Cu plate made of Cu or Cu alloy so that the Cu plate is disposed on one side of the ceramic plate;
A first laminate arrangement step of arranging a first laminate of a ceramic plate and a Cu plate between a pair of discharge plasma sintering electrodes;
A first joining step for joining the ceramic plate and the Cu plate of the first laminate by passing a pulse current between the electrodes in a state in which conduction between the two electrodes is ensured;
A laminated body of a ceramic plate and a Cu plate obtained by the first joining step and an Al plate made of Al or an Al alloy are laminated so that the Al plate is disposed on the other surface of the ceramic plate of the joined body. A second laminating step,
A second laminate arrangement step of arranging the second laminate of the joined body and the Al plate between a pair of discharge plasma sintering electrodes;
A second joining step of joining the ceramic plate and the Al plate of the second laminate by passing a pulse current between the electrodes in a state in which conduction between the two electrodes is ensured. A method for producing a laminated material. In the first joining step, joining is performed at a temperature lower than the melting point of the Cu plate,
The method for manufacturing a laminated material according to claim 5, wherein in the second bonding step, bonding is performed at a temperature lower than the melting point of the Al plate. In the first bonding step, the bonding is performed while pressing the first stacked body at 10 to 100 MPa from both sides in the stacking direction,
The method for producing a laminated material according to claim 5 or 6, wherein in the second joining step, joining is performed while pressing the second laminated body at 10 to 100 MPa from both sides in the laminating direction. In the first bonding step, bonding is performed in an inert gas atmosphere or a vacuum atmosphere,
The method for manufacturing a laminated material according to any one of claims 5 to 7, wherein in the second bonding step, bonding is performed in an inert gas atmosphere or a vacuum atmosphere.

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