WO2024111507A1

WO2024111507A1 - Method for manufacturing bonded body, aggregate substrate, and power module

Info

Publication number: WO2024111507A1
Application number: PCT/JP2023/041332
Authority: WO
Inventors: 篤士酒井; 朋幸原田; 賢久上島; 賢太郎中山; 智也山口
Original assignee: デンカ株式会社
Priority date: 2022-11-25
Filing date: 2023-11-16
Publication date: 2024-05-30
Also published as: JPWO2024111507A1

Abstract

Provided is a bonded body 100 comprising a ceramic plate, a metal plate, and a bonding portion that includes a brazing material component and bonds the ceramic plate and the metal plate. The bonding portion has a creep-up portion that covers the entirety of an edge portion of a second main surface that is on the opposite side from a first main surface on the ceramic plate-side of the metal plate. Also provided is an aggregate substrate comprising a ceramic plate for multiple pieces, a plurality of metal plates, and a plurality of bonding portions that include a brazing material component and bond the ceramic plate and the plurality of metal plates. At least one of the plurality of bonding portions has a creep-up portion that covers the entirety of an edge portion of a second main surface that is on the opposite side from a first main surface on the ceramic plate-side of the metal plate that is bonded by the bonding portion.

Description

Joint body and manufacturing method thereof, aggregate substrate, and power module

This disclosure relates to a joint and its manufacturing method, an assembly substrate, and a power module.

As industrial equipment such as robots and motors become more sophisticated, power modules that control large currents and high voltages are being used. The circuit boards included in such power modules include a ceramic substrate and a copper plate, which are joined via a brazing material containing an active metal. Patent Document 1 proposes a method for manufacturing an insulated circuit substrate, which includes a laminate formation process in which a laminate is formed by arranging the ceramic substrate on one side thereof via the brazing material, and a bonding process in which a circuit layer metal plate is bonded to one side of the ceramic substrate by applying pressure and heat in the lamination direction to the laminate to form a circuit layer.

Since such circuit boards are becoming smaller, they may be positioned using an image recognition device when mounted on a semiconductor device or the like. For example, Patent Document 2 proposes providing a recessed portion with a predetermined depth on the surface of the metal layer and using this recessed portion as a positioning marker for image recognition processing.

JP 2020-155444 A JP 2005-294668 A

Image recognition technology is expected to be used not only when manufacturing power modules as in Patent Document 2, but also for alignment when manufacturing various electronic devices. Therefore, the present disclosure provides a bonded body that allows for highly accurate alignment using image recognition technology, and a manufacturing method thereof. The present disclosure also provides an assembly substrate that allows for efficient production of such a bonded body. The present disclosure also provides a power module with excellent reliability by using such a bonded body.

One aspect of the present disclosure provides the following conjugate:

[1] A ceramic plate, a metal plate, and a joint portion that joins the ceramic plate and the metal plate and contains a brazing material component;
The joint portion has a creeping portion that covers the entire peripheral portion of a second main surface of the metal plate opposite to a first main surface on the ceramic plate side.

The above-mentioned joint comprises a joint having a creeping portion that covers the entire peripheral portion of the second main surface of the metal plate. Since this creeping portion covers the peripheral portion of the second main surface of the metal plate without interruption, the outline of the metal plate can be clearly identified. Furthermore, since the creeping portion contains a brazing material component, it is a different color from the metal plate that does not contain the brazing material component. For this reason, the position of the metal plate (joint) can be identified using image recognition technology, and the metal plate (joint) can be aligned with high precision. If such a joint is used as a component of a semiconductor device, etc., the reliability of the semiconductor device, etc. can be improved.

The bonded body of [2] above may be any of the following [2] to [5].

[2] The bonded body according to [1], wherein the creeping-up portion is used to identify the position of the bonded body.
[3] The bonded body according to [1] or [2], wherein the minimum value of the width L of the rising portion on the second main surface is 0.1 mm or more.
[4] The bonded body according to any one of [1] to [3], wherein the maximum value of the width L of the raised portion on the second main surface is 2.0 mm or less.
[5] The joined body according to any one of [1] to [4], wherein the metal plate has a thickness of 0.5 mm or more.

The joint of [2] above uses the creeping portion to identify the position of the joint. In other words, the creeping portion may be used as a position identification means. When such a joint is used as a component of a semiconductor device or the like, it is possible to align the metal plate with high precision and smoothly, thereby improving the reliability and manufacturing efficiency of the semiconductor device.

The bonded body of [3] above can make the width L of the creeping portion sufficiently large, so that the position of the metal plate can be detected with higher reliability using image recognition technology. The bonded body of [4] above can prevent the width L of the creeping portion from becoming excessive, thereby preventing an increase in electrical resistance caused by a component such as a semiconductor chip mounted on the second main surface of the metal plate being connected to the creeping portion. This can further improve the reliability of a semiconductor device including a semiconductor chip or the like. The bonded body of [5] above can prevent the width of the creeping portion from becoming excessive. This can further improve the reliability of a semiconductor device including a semiconductor chip or the like.

One aspect of the present disclosure provides the following assembly substrate:

[6] An aggregate substrate comprising a multi-cavity ceramic plate, a plurality of metal plates, and a plurality of joints that join the ceramic plate and the plurality of metal plates and contain a brazing material component, at least one of the joints having a creeping portion that covers the entire peripheral portion of a second main surface of the metal plate that is joined at the joint, the second main surface being opposite to the first main surface on the ceramic plate side.

In the collective substrate of [6] above, at least one joint has a creeping portion that covers the entire peripheral portion of the second main surface of the metal plate. Since this creeping portion covers the peripheral portion of the second main surface of the metal plate without interruption, the outline of the metal plate can be clearly identified. Furthermore, since the creeping portion contains a brazing material component, it is a different color from the metal plate that does not contain the brazing material component. For this reason, the position of the metal plate can be identified using image recognition technology, and the metal plate can be aligned with high precision. If the joint obtained from such a collective substrate is used as a component of a semiconductor device, etc., the reliability of the semiconductor device, etc. can be improved.

One aspect of the present disclosure provides the following method for producing a joint body:

[7] a coating step of coating a brazing material on a main surface of a ceramic plate to provide a coating layer;
a lamination step of laminating the coating layer and the metal plate so that the metal plate and the coating layer face each other to produce a laminate;
a joining step of heating the laminate to join the metal plate and the ceramic plate with a joint portion containing a brazing material component,
A method for manufacturing a joint, wherein, in the coating process, the thickness of the end portion of the coating layer is made thicker than that of the center portion, and, in the joining process, the joint is formed having a creeping portion that covers the entire peripheral portion of a second main surface of the metal plate opposite to a first main surface on the ceramic plate side.

The bonded body obtained by the manufacturing method [7] above has a bonded part having a creeping part that covers the entire peripheral part of the second main surface of the metal plate. Since this creeping part covers the peripheral part of the second main surface of the metal plate without interruption, the outline of the metal plate can be clearly identified. Furthermore, since the creeping part contains a brazing material component, it is a different color from the metal plate that does not contain the brazing material component. For this reason, the position of the metal plate can be identified by image recognition technology, and the metal plate can be aligned with high precision. If such a bonded body is used as a component of a semiconductor device, etc., the reliability of the semiconductor device, etc. can be improved.

The manufacturing method of the above [7] may be the following [8].

[8] The ceramic plate is a first ceramic plate for a multi-cavity molding,
In the coating step, a plurality of the coating layers are provided on the main surface of the first ceramic plate,
In the lamination step, the first ceramic plate and the plurality of metal plates are laminated so as to sandwich the plurality of coating layers therebetween to prepare the laminate;
The method for producing a bonded body according to [7], further comprising the steps of: dividing the first ceramic plate after the bonding step to obtain a plurality of the bonded bodies.

In the manufacturing method [8] above, image recognition technology can be used to simultaneously manufacture multiple joined bodies, allowing the metal plates to be aligned with high precision. This results in excellent production efficiency for joined bodies.

One aspect of the present disclosure provides the following power module:

[9] A power module comprising a bonded body according to any one of [1] to [5] above, or a bonded body obtained by the manufacturing method according to [7] or [8] above, and a semiconductor element electrically connected to the metal plate of the bonded body.

The power module of [9] above comprises any of the above-mentioned joined bodies or a joined body obtained by any of the above-mentioned manufacturing methods, and a semiconductor element electrically connected to the metal plate of the joined body. Such a power module comprises any of the above-mentioned joined bodies or a joined body obtained by any of the above-mentioned manufacturing methods. Such a joined body allows for highly accurate alignment of the metal plate when manufacturing the power module, using image recognition technology or the like.

By using image recognition technology, it is possible to provide a bonded body that allows for highly accurate alignment, and a method for manufacturing the same. The present disclosure also provides an assembly substrate that allows for efficient production of such a bonded body. The present disclosure also provides a highly reliable power module by using such a bonded body.

FIG. FIG. 2 is a cross-sectional view of the joint body taken along the thickness direction of the metal plates. FIG. FIG. 2 is a cross-sectional view of a power module. FIG. 2 is a diagram showing a support plate and a temporary fastening material attached thereto. FIG. 13 is a diagram showing a support plate and a metal plate temporarily fixed thereto. 13A and 13B are diagrams showing a grid jig and a metal plate temporarily fixed to a support plate using the grid jig; 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7. 13 is a diagram showing a state in which a coating layer formed on a ceramic plate and a support plate to which a metal plate is temporarily attached are laminated. FIG. FIG. 2 is a perspective view showing a portion of a first stack. 1 is a cross-sectional view taken along the thickness direction of a ceramic plate provided with a coating layer and a metal plate bonded to the coating layer. 3 is a cross-sectional view of a plurality of first laminates and a second laminate formed by stacking the first laminates. FIG. FIG. FIG. 4 is a cross-sectional view showing a state in which the second laminate is pressed by a pressing device. FIG. 4 is a cross-sectional view showing a state when a second stack is introduced into a heating device. 11 is a cross-sectional view showing a state in which a support plate is removed from the collective substrate. FIG.

Below, embodiments of the present disclosure will be described with reference to the drawings as needed. However, the following embodiments are merely examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents. In the description, the same reference numerals are used for the same elements or elements having the same functions, and overlapping descriptions are omitted as needed. Furthermore, unless otherwise specified, the positional relationships, such as up, down, left, right, etc., are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of each element are not limited to the ratios shown. In this disclosure, each numerical range indicated by the symbol "~" includes a lower limit and an upper limit. In other words, a numerical range indicated by "A~B" means A or more and B or less. A numerical range that combines a numerical range having only an upper limit and a numerical range having only a lower limit is also included in this disclosure. A numerical range in which the upper limit or lower limit of each numerical range is replaced with the numerical value of any of the examples is also included in this disclosure. When multiple materials are exemplified, one of them may be used alone, or multiple materials may be used in combination.

In one embodiment, the joint includes a ceramic plate, a metal plate, and a joint portion that joins the ceramic plate and the metal plate and contains a brazing material component. The joint portion covers the peripheral portion of a second main surface of the metal plate opposite the first main surface on the ceramic plate side. The joint may be, for example, a circuit board. The metal plate may form an electric circuit or may be a heat sink. There may be one or more metal plates joined to one main surface of a ceramic plate. The metal plate may be joined to only one main surface of the ceramic plate, or to both main surfaces.

The material of the ceramic plate is not particularly limited, and may be, for example, a sintered nitride, a sintered carbide, or a sintered oxide. Specific examples include silicon nitride sintered body, aluminum nitride sintered body, aluminum oxide sintered body, and silicon carbide sintered body. If the joint and the ceramic plate are different colors, the accuracy of image recognition can be sufficiently high. From this perspective, the ceramic plate may be, for example, a sintered silicon nitride. The thickness of the ceramic plate may be, for example, 0.2 to 2 mm, or 0.25 to 1.5 mm.

The metal plate may be, for example, a copper plate. The copper plate usually has a different color from the bonding layer, so that the creeping portion can be image-recognized with high accuracy. The metal plate may be obtained by punching. If the metal plate has a sag (sag surface) and a burr (burr surface), it may be bonded to the ceramic plate via a joint so that the burr is located closer to the ceramic plate than the sag. This allows the creeping portion to cover the peripheral portion of the second main surface of the metal plate with high uniformity. The shape of the metal plate is not particularly limited, and may be a prismatic or quadrangular prism shape. At least some of the corners of the metal plate may be chamfered.

The thickness of the metal plate may be 0.5 mm or more, 0.6 mm or more, 0.7 mm or more, or 0.8 mm or more. This prevents the width L of the creeping portion on the second main surface of the metal plate from becoming too large. The thickness of the metal plate may be 3 mm or less, 2 mm or less, or 1.5 mm or less. This allows the joint to be made smaller and lighter. An example of the thickness range of the metal plate is 0.5 to 3 mm.

The bonding layer is a layer that bonds the ceramic plate and the metal plate, and contains a brazing material component. For this reason, it is sometimes called a brazing material layer. The bonding layer may contain, for example, silver derived from the brazing material, or silver and copper. The bonding layer may further contain one or more metals selected from the group consisting of tin and active metals derived from the brazing material. In the bonding layer, the two or more metals may be an alloy. The active metal may contain one or more metals selected from the group consisting of titanium, hafnium, zirconium, and niobium. The silver and copper contained in the bonding layer may be contained as an alloy such as an Ag-Cu eutectic alloy. The silver content in the bonding layer may be 45 to 95 mass% or 50 to 95 mass% in terms of Ag. The total content of silver and copper in the bonding layer may be 65 to 100 mass%, 70 to 99 mass%, or 90 to 98 mass% in terms of Ag and Cu, respectively. This makes it possible to sufficiently reduce residual stress in the bonding layer while improving the density of the bonding layer.

The content of the active metal in the bonding layer may be 0.5 to 8 parts by mass per 100 parts by mass of the total of Ag and Cu. By making the content of the active metal 0.5 parts by mass or more, it is possible to improve the bond between the ceramic plate and the bonding layer. On the other hand, by making the content of the active metal 8 parts by mass or less, it is possible to suppress the formation of a brittle alloy layer at the bonding interface.

The metal contained in the bonding layer may be contained as a nitride, oxide, carbide, or hydride. As an example, the bonding layer may contain titanium nitride and/or titanium hydride (TiH ₂ ). This allows the bonding strength between the ceramic plate and the metal plate to be sufficiently high. The content of TiH ₂ relative to a total of 100 parts by mass of Ag and Cu may be, for example, 1 to 8 parts by mass.

Figure 1 is a plan view of an example of a joint, and Figure 2 is a cross-sectional view taken along line II-II in Figure 1. The joint 100 comprises a ceramic plate 20, a metal plate 60, and a joint 40 that joins the ceramic plate 20 and the metal plate 60 and contains a brazing material component. The joint 40 has a creeping portion 46 that covers the entire peripheral portion of the second main surface 60A of the metal plate 60 opposite the first main surface 60B on the ceramic plate 20 side.

When viewed in a plan view as in FIG. 1, the minimum value of the width L of the creeping portion 46 may be 0.1 mm or more, or 0.2 mm or more. By increasing the minimum value of the width L in this way, the position of the metal plate 60 can be identified with sufficiently high accuracy by image recognition technology. In addition, the shape of the metal plate 60 can be detected with high accuracy, and the dimensions of the metal plate 60 can be measured with high accuracy. The maximum value of the width L of the creeping portion 46 may be 2.0 mm or less, 1.9 mm or less, 1.8 mm or less, or 1.5 mm or less. This makes it possible to suppress poor connection and increased electrical resistance caused by the semiconductor chip mounted on the second main surface 60A of the metal plate 60 being connected to the creeping portion 46. The width L can be measured in an observation image obtained by observing a planar image such as that in FIG. 1 with an optical microscope and focusing on the main surface 60A of the metal plate 60.

The average value of the width L may be 0.2 mm or more, 0.3 mm or more, 0.4 mm or more, or 0.5 mm or more. By increasing the average value of the width L, the position of the metal plate 60 can be identified with even higher accuracy. The average value of the width L may be 1.8 mm or less, 1.5 mm or less, or 1.3 mm or less. By preventing the average value of the width L from becoming excessive, it is possible to prevent poor connection and increased electrical resistance caused by the semiconductor chip mounted on the second main surface 60A of the metal plate 60 being connected to the creeping portion 46. In addition, the metal plate 60 can be made smaller, thereby reducing the size of the joint 100. An example of the numerical range of the average value of the width L is 0.2 to 1.8 mm. This allows the above-mentioned characteristics to be achieved in a well-balanced manner. The average value of the width L is the arithmetic mean value of the measured values of the width L at 20 points arbitrarily selected in the image observed by the optical microscope described above.

The maximum, minimum and average values of width L can be adjusted by the amount of brazing material applied when joining the ceramic plate 20 and the metal plate 60, the pressure during joining, and the heating temperature and heating time during joining. The difference between the maximum and minimum values of width L may be 1.7 mm or less, 1.5 mm or less, 1.3 mm or less, or 1.0 mm or less. By reducing this difference, the variation in width L of the creeping portion 46 is reduced, and the position of the metal plate 60 can be detected with higher reliability using image recognition technology. The difference between the maximum and minimum values of width L may be 0.1 mm or more from the viewpoint of making it easier to manufacture the joined body 100. An example of the numerical range of the difference in width L is 0.1 to 1.7 mm.

2, the joint 40 covers the side surface 62 of the metal plate 60 and may have a skirt portion 44 that widens away from the side surface 62 of the metal plate 60 as it approaches the main surface 20A of the ceramic plate 20 from the main surface 60A of the metal plate 60. The inclined surface 44S that defines the outline of the skirt portion 44 extends to the main surface 20A of the ceramic plate 20. The bottom of the skirt portion 44 is in contact with the main surface 20A of the ceramic plate 20 and forms the outer edge 45 of the joint 40. By having the skirt portion 44, the joint 40 can suppress local stress concentration at the joint between the outer edge of the metal plate and the ceramic plate. Therefore, the connection reliability between the ceramic plate 20 and the metal plate 60 can be sufficiently increased.

In the joined body 100 of FIG. 1 and FIG. 2, a metal plate 60 (first metal plate) is joined to one main surface 20A of the ceramic plate 20 by a joint 40 (first joint). In a modified example, a second metal plate may be joined to the other main surface 20B of the ceramic plate 20 by a second joint. The second joint may have a shape similar to that of the first joint. The size and shape of the first metal plate and the second metal plate may be the same or different. The number of first metal plates 60 (second metal plates) joined to the main surface 20A (main surface 20B) is not limited to one, and may be multiple. The size and shape of the multiple first metal plates 60 (second metal plates) may be the same or different. In this way, when multiple metal plates are joined to the ceramic plate 20, it is sufficient that the entire periphery of the second main surface of at least one metal plate is covered by the creeping portion 46.

In one embodiment, the assembly substrate includes a ceramic plate (first ceramic plate) for multiple pieces, a plurality of metal plates having side surfaces formed by cut surfaces, and a plurality of joints that join the ceramic plate and each of the plurality of metal plates and contain a brazing material component. At least one of the plurality of joints has a creeping portion that covers the entire peripheral portion of the second main surface opposite the first main surface on the ceramic plate side of the metal plate joined at the joint. The metal plate whose peripheral portion of the second main surface is covered by such a creeping portion can be smoothly located by image recognition technology. All of the plurality of joints may have a creeping portion that covers the entire peripheral portion of the second main surface opposite the first main surface on the ceramic plate side of the metal plate joined at these joints. The minimum value, maximum value, and average value of the width L of each creeping portion are as described above.

Figure 3 is a perspective view showing an example of an aggregate substrate. The aggregate substrate 200 comprises a ceramic plate 21 and a plurality of metal plates 60 joined to each of the main surface 21A and the main surface 21B of the ceramic plate 21. The ceramic plate 21 is divided into a plurality of sections by division lines SL1, SL2 formed on the main surface 21A. The main surface 21A is provided with a plurality of division lines SL1 extending along a first direction and arranged at equal intervals, and a plurality of division lines SL2 extending along a second direction perpendicular to the first direction and arranged at equal intervals. The division lines SL1 and SL2 are perpendicular to each other.

The demarcation lines SL1, SL2 may be, for example, a number of depressions arranged in a straight line, or may have linear grooves. Specifically, they may be scribe lines formed with laser light. Examples of laser sources include carbon dioxide lasers and YAG lasers. Scribe lines can be formed by intermittently irradiating laser light from such laser sources. Note that the demarcation lines SL1, SL2 do not have to be arranged at equal intervals, and are not limited to being perpendicular. Furthermore, they may be curved rather than straight, or bent.

The ceramic plate 21 has a plurality of partition regions DR defined by partition lines SL1 and SL2. A metal plate 60 is provided in each of the plurality of partition regions DR. The plurality of metal plates 60 are independent of each other. By dividing the aggregate substrate 200 along the partition lines SL1 and SL2, a joint body 100 including the ceramic plate 20 can be obtained.

Each of the multiple metal plates 60 on the main surface 21A of the ceramic plate 21 is joined to the ceramic plate 21 by a joint 40. The multiple joints 40 each have a skirt portion 44 on the side surface 62 of the metal plate 60, similar to the joint 40 shown in FIG. 1. The skirt portion 44 covers part or all of the side surface 62 of the metal plate 60 and part of the main surface 21A of the ceramic plate 21. Each of the multiple joints 40 has a creeping portion 46 that covers the entire peripheral portion of the main surface 60A of the metal plate 60. The creeping portion 46 extends continuously from the top of the skirt portion 44 to the peripheral portion of the main surface 60A. The minimum, maximum, and average value of the width L of each creeping portion 46 may be the same as the numerical range described for the joint 100. Such an aggregate substrate 200 can be aligned or dimensionally measured with high accuracy using image recognition technology. Furthermore, by dividing the substrate assembly 200 along the dividing lines SL1 and SL2, nine bonded bodies can be obtained that can be aligned or dimensionally measured with high precision using image recognition technology.

Each of the multiple metal plates 60 on the main surface 21B of the ceramic plate 21 may also be joined to the ceramic plate 21 by a joint having a shape similar to that of the joint 40 that joins the metal plates 60. This joint may have a creeping portion similar to the joint 40, covering the entire peripheral portion of the main surface of the multiple metal plates 60 opposite the main surface on the ceramic plate 21 side. If a creeping portion is also formed on the peripheral portion of the main surface of the metal plate 60 on the main surface 21B of the ceramic plate 21, alignment using image recognition technology can be performed using the creeping portions on the front and back, further improving alignment accuracy.

The joint 100 can be aligned with high precision using image recognition technology, and therefore may be mounted on a power module as a circuit board. The metal plate 60 may function as a circuit board having the function of transmitting electrical signals, or as a heat sink having the function of transmitting heat. The metal plate 60 may also have both the function of transmitting heat and the function of transmitting electrical signals. The joint 100 can be aligned with high precision using image recognition technology, and therefore a power module with excellent reliability can be manufactured. In this way, the joint 100 is suitable as a component to be mounted on a power module that requires high reliability.

The multiple metal plates 60 and multiple joints 40 in the collective substrate 200 in FIG. 3 all have the same size and shape. In a modified example, the multiple metal plates 60 and multiple joints 40 may have different sizes and shapes. In this case, it is not necessary for all of the multiple joints 40 to have the creeping portion 46, as long as at least one joint 40 has the creeping portion 46. However, if all of the multiple joints 40 have the creeping portion 46, it is possible to mass-produce joints that can be aligned with high precision using image recognition technology.

The power module according to one embodiment includes a joint (circuit board) and a semiconductor element electrically connected to the metal plate of the joint. The joint may be the joint 100 described above or a modified version thereof. The description of the joint 100 and its modified versions applies to the power module of this embodiment. Such a power module has excellent reliability because the joint, which is a component, is aligned with high accuracy by image recognition technology. In addition, the power module can be efficiently manufactured by using image recognition technology. The joint and the semiconductor element may be sealed with resin. As the image recognition technology, for example, a normal image recognition device including an image acquisition unit such as a CCD camera and an information processing unit that obtains position information from the acquired image information may be used. High-precision alignment can be achieved using a positioning device that adjusts the position of the joint based on the position information from such an image recognition device.

Figure 4 is a cross-sectional view showing an example of a power module. The power module 300 includes a base plate 90 and a joint 101 that is joined to one side of the base plate 90 via solder 82. A metal plate 61 on one side of the joint 101 is joined to the base plate 90 via the solder 82.

A semiconductor element 80 is attached to the metal plate 60 on the other side of the joint 101 via solder 81. The semiconductor element 80 is connected to a predetermined location of the metal plate 60 with a metal wire 84 such as an aluminum wire. In this way, the semiconductor element 80 and the metal plate 60 are electrically connected. To electrically connect the outside of the housing 86 to the metal plate 60, one of the metal plates, metal plate 60a, is connected to an electrode 83 that penetrates the housing 86 via solder 85.

A housing 86 is disposed on one of the main surfaces of the base plate 90, and is integrated with the main surface to house the joint 101. The housing space formed by the one of the main surfaces of the base plate 90 and the housing 86 is filled with resin 95. The resin 95 seals the joint 101 and the semiconductor element 80. The resin may be, for example, a thermosetting resin or a photocurable resin.

A cooling fin 92, which serves as a heat dissipation member, is joined to the other main surface of the base plate 90 via grease 94. Screws 93 are attached to the ends of the base plate 90 to secure the cooling fin 92 to the base plate 90. The base plate 90 and the cooling fin 92 may be made of aluminum. The base plate 90 and the cooling fin 92 function well as heat dissipation parts due to their high thermal conductivity.

The metal plate 60 and the metal plate 61 are electrically insulated by the ceramic plate 20. The metal plate 60 (60a) may form an electrical circuit. The metal plate 60 and the metal plate 61 are respectively joined to the main surface 20A and the main surface 20B of the ceramic plate 20 by a joint (not shown) containing a brazing material component. The joint has a skirt portion 44 and a creeping portion 46 as shown in Figures 1 and 2. The average value and standard deviation of the width L of the creeping portion 46 are as described above. The metal plate 60 (metal plate 61) is aligned and dimensionally measured using such a creeping portion 46. Therefore, the power module 300 has excellent reliability.

The manufacturing method of the bonded body according to one embodiment includes a punching process in which a metal substrate is punched to obtain a plurality of metal plates 60, a temporary fixing process in which the plurality of metal plates 60 are temporarily fixed to each of a pair of support plates using a first positioning jig, a coating process in which a brazing material is applied to the main surface 21A and the main surface 21B of a ceramic plate 21 for multiple pieces and dried to provide a plurality of coating layers on each of the main surface 21A and the main surface 21B, a lamination process in which the ceramic plate 21 is sandwiched between the pair of support plates using a second positioning jig so that the plurality of coating layers and the plurality of metal plates 60 face each other to produce a laminate, a bonding process in which the laminate is heated to bond the metal plate 60 and the ceramic plate 21, and a finishing process in which the ceramic plate 21 to which the metal plate 60 is bonded is divided to obtain a plurality of bonded bodies 100.

In the punching process, the metal base material is punched out using, for example, a die. This results in a metal plate 60 whose side surfaces are cut surfaces. If the metal plate 60 has a rectangular prism shape, all four side surfaces may be cut surfaces. The metal plate 60 may have a sag on one main surface 60A and a burr on the other main surface 60B. This allows the rising portion 46 to be formed smoothly in the joining process.

In the temporary fixing process, the metal plate 60 is fixed to a predetermined position A1 on the support plate TP by a temporary fixing material 11 shown in FIG. 5. The support plate TP may be, for example, a carbon plate. The temporary fixing material 11 may disappear when heated in the joining process. The predetermined position A1 on the support plate TP is a position corresponding to the intended joining position A2 (see FIG. 9) of the metal plate 60 fixed on the ceramic plate 21. Specifically, it is a position where the metal plate 60 is placed at the intended joining position A2 on the ceramic plate 21 when the support plate TP is placed in an appropriate position on the ceramic plate 21.

As shown in FIG. 5, a single support plate TP is divided into a plurality of regions for the purpose of forming a plurality of joints. A temporary fixing material 11 for temporarily fixing the metal plate 60 is provided in each of the plurality of regions. As an example of the temporary fixing material 11, a sheet-type adhesive can be used. The sheet-type adhesive is an adhesive tape that can bond the metal plate 60 to the support plate TP at room temperature. The adhesive tape can be bonded on both sides, and includes an adhesive layer made of an organic component and a release film that covers both sides of the adhesive layer. The release film is a member that protects both sides of the adhesive layer and is peeled off when used. The release film may be, for example, a transparent PET film. One side of the adhesive layer of the temporary fixing material 11 may be adhered to a predetermined position A1 of the support plate TP. Then, as shown in FIG. 6, the metal plate 60 is adhered to the other side of the adhesive layer of the temporary fixing material 11.

The adhesive component forming the adhesive layer can be a material capable of bonding the support plate TP and the metal plate 60. The adhesive component can be, for example, an acrylic adhesive, a urethane adhesive, or a rubber adhesive. These adhesives are composed of organic components. Therefore, they are decomposed during heating in the bonding process. By adjusting the amount used, it is possible to adjust the amount so that no residue remains in the bonded body 100.

An acrylic adhesive is an adhesive made of acrylic polymer. A urethane adhesive is an adhesive made of polyurethane (a condensation polymerization product of a compound with an isocyanate group and a compound with a hydroxyl group). A rubber adhesive is an adhesive made of natural or synthetic rubber. Examples of synthetic rubber include acrylic rubber and styrene butadiene rubber.

The temporary fixing material 11 may be an adhesive tape that does not have a base layer that supports the adhesive layer. The temporary fixing material 11 may be a spray-type adhesive. A spray-type adhesive is a liquid adhesive that is capable of adhering the metal plate 60 to the support plate TP at room temperature and is made of organic components. This adhesive is intended to be used by spraying. For example, the adhesive can be sprayed onto a predetermined position A1 of the support plate TP, and the metal plate 60 can be adhered and fixed to the support plate TP via the adhesive as shown in FIG. 6.

The spray-type adhesive may be a solvent-based adhesive, a rubber-based adhesive, or a synthetic resin-based adhesive. In the case of a solvent-based adhesive, the adhesive component is an organic solvent, and for example, hexane, isohexane, toluene, acetone, butane, etc. can be used. In the case of a rubber-based adhesive, the adhesive component may be natural rubber or synthetic rubber. For example, acrylic rubber, styrene butadiene rubber, etc. can be used as the synthetic rubber. In the case of a synthetic resin-based adhesive, the adhesive component is a synthetic resin, and acrylic polymer, etc. can be used.

The spray-type adhesive is placed at a predetermined position A1 on the support plate TP by an injector or the like. The injector has, for example, a container and a nozzle part that sprays the adhesive in the container. The container contains liquid adhesive containing a tackifying component and a propellant that sprays the adhesive. As the propellant, for example, dimethyl ether or LPG can be used. The adhesive in the container is sprayed or stopped from inside the container by operating a lever or the like attached to the nozzle part.

When temporarily fixing the metal plate 60 to the temporary fixing material 11 on the support plate TP, a lattice jig 3 as shown in FIG. 7 may be used. The lattice jig 3 is an example of a first positioning jig that positions the metal plate 60 at a predetermined position A1 on the support plate TP. FIG. 7 is a plan view showing the metal plate 60 being temporarily fixed with the temporary fixing material 11 while aligning the metal plate 60 to the predetermined position A1 using the lattice jig 3 installed on the support plate TP. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7.

The lattice jig 3 may be removed from the support plate TP before being introduced into the heating furnace 8 (see FIG. 15) for the joining process. This allows for a high degree of freedom in selecting the material for the lattice jig 3. Examples of materials for the lattice jig 3 include polyethylene (e.g., high-density polyethylene), polypropylene, polyvinyl chloride, AS resin, acrylic resin, A2017 (duralumin), A5052 (aluminum alloy), etc. These materials have excellent workability.

As shown in Figures 7 and 8, the lattice jig 3 has a frame portion 31, a number of alignment holes 32 formed in the frame portion 31, and a pair of handle portions 33 extending outward from the frame portion 31.

The frame 31 has a rectangular shape that is substantially aligned with the outer periphery of the support plate TP, except for the handle portion 33. By setting the frame 31 so that it is aligned with the outer periphery of the support plate TP, the lattice jig 3 can be set in an appropriate position relative to the support plate TP. Inside the area surrounded by the frame 31, multiple vertical wall portions 31a and multiple horizontal wall portions 31b that are perpendicular to each other are provided. A rectangular hole 32 (hole) is formed by the frame 31, the vertical wall portions 31a, and the horizontal wall portions 31b, or by the vertical wall portions 31a and the horizontal wall portions 31b.

When the lattice jig 3 is placed at an appropriate position on the support plate TP, the multiple holes 32 are each positioned so that they are aligned with the outer edge Ed of a predetermined position A1 on the support plate TP. Each of the multiple holes 32 is larger than the metal plate 60 and has a rectangular shape that can accommodate the metal plate 60.

The main surface of the metal plate 60 is generally rectangular, with four corners 64 where adjacent side surfaces 62 are bent and connected. The hole 32 is a rectangular hole into which the metal plate 60 fits, with four (multiple) corners 32a. The metal plate 60 is positioned at a predetermined position A1 when the corners 64 come into contact with a reference corner 32x among the multiple corners 32a of the hole 32. In one example, of the four corners 32a of the hole 32, the lower right corner 32a is set as the reference corner 32x (see Figure 7).

The hole portion 32 has a gap forming portion 32b. The gap forming portion 32b is a portion that forms a gap Sp between the metal plate 60 and the corner portion 64 of the metal plate 60 when the corner portion 64 of the metal plate 60 abuts against the reference corner portion 32x. For example, as shown in Figures 7 and 8, when the corner portion 64 of the metal plate 60 abuts against the reference corner portion 32a, a gap Sp is formed between the left side of the metal plate 60 and the alignment hole portion 32. The portion of the hole portion 32 that forms this gap Sp is the gap forming portion 32b.

For example, after placing the temporary fixing material 11 at a predetermined position A1 on the support plate TP, the lattice jig 3 is placed at an appropriate position on the support plate TP. Alternatively, after placing the lattice jig 3 at an appropriate position on the support plate TP, the temporary fixing material 11 is placed in the hole portion 32 of the lattice jig 3. After placing the lattice jig 3 at the appropriate position on the support plate TP, the metal plate 60 is inserted into the hole portion 32. At this time, the metal plate 60 is aligned to the predetermined position A1 using the lattice jig 3, and the metal plate 60 is fixed to the support plate TP by the temporary fixing material 11.

In addition to temporarily fixing the metal plate 60, a coating process is performed in which a coating layer 12 containing a brazing material is provided on the main surface 21A of the ceramic plate 21. Partition lines SL1, SL2 are formed on the main surface 21A of the ceramic plate 21. The parting lines SL1, SL2 may be scribe lines formed by irradiating a laser beam, for example. Examples of laser beams include a carbon dioxide laser and a YAG laser. Such parting lines SL1, SL2 can be used as cutting lines when dividing the assembly substrate in a later process.

The brazing filler metal may contain Ag in the form of a metal element or a metal compound (alloy), and may contain, in addition to Ag, one or more metals selected from the group consisting of Cu, Sn, and active metals. The two or more metals may be alloyed. The active metal may contain one or more metals selected from the group consisting of Ti, Hf, Zr, and Nb. The brazing filler metal may contain 80 parts by mass or more of Ag per 100 parts by mass of Ag and Cu in total, 90 parts by mass or more, or 95 parts by mass or more. By sufficiently increasing the ratio of Ag to Cu in this way, the timing of melting of the brazing filler metal can be delayed when the laminate is heated in the joining process. Therefore, excessive creeping of the brazing filler metal can be suppressed. In addition, Ag and Cu have a eutectic point near a mass ratio of 72:28. Therefore, the molten brazing filler metal reacts smoothly with the Cu contained in the metal plate to form a eutectic alloy. Therefore, the contact area between the bonding layer and the ceramic plate and the metal plate can be increased, and the creeping portion 46 can be smoothly formed. The brazing material does not need to contain Cu.

The content of the active metal in the brazing filler metal may be 0.5 to 8 parts by mass per 100 parts by mass of the total of Ag and Cu. By making the content of the active metal 0.5 parts by mass or more, it is possible to improve the bond between the ceramic plate and the brazing filler metal. On the other hand, by making the content of the active metal 8 parts by mass or less, it is possible to suppress the formation of a brittle alloy layer at the bonded interface.

The active metal contained in the brazing material may be contained as a nitride, oxide, carbide, or hydride. As an example, the brazing material may contain titanium nitride and/or titanium hydride (TiH ₂ ). This allows the bonding strength between the ceramic plate and the metal plate to be sufficiently high. The content of TiH ₂ relative to a total of 100 parts by mass of Ag and Cu may be, for example, 1 to 8 parts by mass.

The brazing filler metal may contain, in addition to the metal or metal compound described above, an organic solvent, a binder, etc. The viscosity of the brazing filler metal may be, for example, 5 to 20 Pa·s. The organic solvent content in the brazing filler metal may be, for example, 5 to 25 mass %, and the binder content may be, for example, 2 to 15 mass %.

As shown in FIG. 9, a brazing material is applied to one of the main surfaces 21A of the ceramic plate 21 at the intended joining position A2 of the metal plate 60 to form a coating layer 12. The application method may be a roll coater method, a screen printing method, a transfer method, or the like. The intended joining position A2 corresponds to a predetermined position A1 of the support plate TP. The support plate TP is laminated on the ceramic plate 21 so that the metal plate 60 faces the main surface 21A of the ceramic plate 21. At this time, the metal plate 60 faces the intended joining position A2 of the ceramic plate 21.

On the other main surface 21B of the ceramic plate 21, the solder material is applied to the intended joining position A2 of the metal plate 60 to form a coating layer 12. The application method is as described above. This intended joining position A2 corresponds to a predetermined position A1 of another support plate TP. This other support plate TP is laminated on the ceramic plate 21 so that the metal plate 60 faces the main surface 21B of the ceramic plate 21. At this time, the metal plate 60 faces the ceramic plate 21 at the intended joining position A2. In this way, a first laminate Xa as shown in FIG. 10 is formed.

FIG. 11 shows a part of a cross section of a ceramic plate 21 provided with a coating layer 12 when cut along the thickness direction. The coating layer 12 is thicker at the ends surrounding the center than at the center. That is, the coating layer 12 has a thin coating portion 12B in the center and a thick coating portion 12A at the end (periphery). By using such a coating layer 12, the brazing material is sufficiently filled between the end 65 of the metal plate 60 and the ceramic plate 21. If such a laminate is heated in the joining process described later, the brazing material component can be sufficiently caused to creep up to the side surface 62 and main surface 60A of the metal plate 60. In addition, it is possible to sufficiently prevent the joining between the metal plate 60 and the ceramic plate 21 from becoming insufficient. Although only one coating layer 12 is shown in FIG. 11, the other coating layers 12 may have the same shape.

The width of the coating layer 12 in FIG. 11 is the same as the width of the metal plate 60, but is not limited to this. For example, the coating layer 12 may have a protruding portion that extends outward from the side surface 62 of the metal plate 60 along the main surface 21A of the ceramic plate 21. In this way, if the coating layer 12 has a protruding portion at the end, the width L of the creeping portion 46 on the main surface 60A of the metal plate 60 shown in FIG. 1 and FIG. 2 can be sufficiently increased. In addition, the skirt portion 44 on the side surface 62 of the metal plate 60 can be sufficiently increased to further improve the joining reliability. In addition, by increasing the width and thickness of the thick coating portion 12A at the end of the coating layer 12, the width L of the creeping portion 46 shown in FIG. 1 and FIG. 2 can be increased. By reducing the width and thickness of the thick coating portion 12A at the end of the coating layer 12, the width L of the creeping portion 46 shown in FIG. 1 and FIG. 2 can be reduced.

As shown in Figure 12, in the lamination process, the ceramic plate 21 on which the coating layer 12 is formed and a pair of support plates TP to which the metal plate 60 is temporarily attached are laminated while being aligned using an enclosing jig 5 to obtain the first laminate Xa of Figure 10. A similar procedure is repeated to obtain a plurality of first laminates Xa, which are then stacked. In this way, a second laminate XA is obtained in which a plurality of first laminates Xa are stacked. For alignment during lamination, an enclosing jig 5 as shown in Figures 12 and 13 can be used.

The enclosing jig 5 is a frame-shaped device that surrounds the rectangular periphery of the second laminate XA, and is an example of a second alignment jig that aligns the metal plate 60 and the ceramic plate 21 when stacking them. The enclosing jig 5 has an abutting wall portion 50 that is arranged along the periphery of the multiple first laminates Xa (FIG. 13). The abutting wall portion 50 has

multiple partition walls

51, 52 that can be separated. For example, the abutting wall portion 50 has a first partition wall portion 51 that is L-shaped in a plan view and a second partition wall portion 52 that is L-shaped in a plan view. By combining the first partition wall portion 51 and the second partition wall portion 52, a cubic or rectangular storage space is formed in which the multiple first laminates Xa can be stored.

The first laminate Xa forming the second laminate XA is rectangular in plan view, so the second laminate XA has four corners Xb. The first dividing wall 51 has a corner 51m bent to fit along the corner Xb of the second laminate XA. The second dividing wall 52 has a corner 52m bent to fit along the corner Xb of the second laminate XA.

The first dividing wall 51 has a first alignment wall 51a and a second alignment wall 51b. The second dividing wall 52 has a third alignment wall 52a and a fourth alignment wall 52b. The first alignment wall 51a and the third alignment wall 52a are arranged opposite each other to sandwich the second laminate XA (first laminate Xa) accommodated in the storage space. The second alignment wall 51b and the fourth alignment wall 52b are arranged opposite each other to sandwich the second laminate XA (first laminate Xa) accommodated in the storage space.

The enclosure jig 5 has an adjustment section 53 that connects the first partition wall section 51 and the second partition wall section 52. The adjustment section 53 is configured to be able to adjust the volume of the storage space enclosed by the first partition wall section 51 and the second partition wall section 52.

The adjustment portion 53 includes, for example, a plurality of slits 53a (through holes) formed in the first dividing wall portion 51, a plurality of screw portions 54 inserted into the plurality of slits 53a, and a plurality of screw holes 55 formed in the second dividing wall portion 52. The second dividing wall portion 52 includes an end portion 52c that can abut against the first dividing wall portion 51, and the end portion 52c is provided with a screw hole 55 so as to overlap the slit 53a of the first dividing wall portion 51. The screw portion 54 includes a shaft portion 54a and a head portion 54b (locking portion). The shaft portion 54a is inserted into the slit 53a and is screwed into the screw hole 55. The head portion 54b is formed at one end of the shaft portion 54a and interferes with the periphery of the slit 53a of the first dividing wall portion 51. The periphery of the slit 53a is an engagement receiving portion 53b that receives the interference of the head portion 54b. The storage space shrinks when the screw part 54 is tightened, and expands when it is loosened.

As shown in FIG. 12, the enclosing jig 5 is placed on the base 71 of the pressure device 7. The multiple first laminates Xa are stacked in the storage space of the enclosing jig 5. The multiple first laminates Xa are stacked on the base 71 while being aligned by the enclosing jig 5. This results in a second laminate XA in which the multiple first laminates Xa are stacked in the storage space of the enclosing jig 5. In a modified example, after all the first laminates Xa have been stacked, the enclosing jig 5 may be placed around the second laminate XA to align them. This results in a second laminate XA in which the stacked positions of the multiple first laminates Xa are aligned with each other.

As shown in Figure 14, after stacking the multiple first laminates Xa, the second laminate XA is sandwiched between a base 71 and a cover plate 73 and pressurized. The pressure device 7 includes a base 71 that supports the second laminate XA, multiple pillars 72 erected from the base 71, a cover plate 73 that abuts against the upper surface of the second laminate XA, multiple elastic bodies 74 arranged on the cover plate 73, a pressure plate 75 that is installed on the elastic bodies 74 and presses the elastic bodies 74, and a nut 76 (holding part) that holds the pressure plate 75 in a predetermined position.

The column 72 has a screw groove formed therein. The column 72 penetrates the cover plate 73 and the pressure plate 75. The nut 76 is screwed onto the upper end of the column 72 and abuts against the upper surface of the pressure plate 75. An elastic body 74 is disposed between the cover plate 73 and the pressure plate 75. When the nut 76 is tightened, the pressure plate 75 is pressed down, compressing the elastic body 74. As a result, the second laminate XA is pressurized via the cover plate 73. This allows the metal plate 60 and the ceramic plate 21, which are aligned with high precision, to be sufficiently bonded via the coating layer 12. The width L of the creeping layer can be adjusted by changing the pressure applied here.

When sufficient adhesion has been achieved, the enclosing jig 5 is divided and separated from the second laminate XA while the second laminate XA is kept pressurized by the pressure device 7. The pressurized second laminate XA is stable, and even if the enclosing jig 5 is separated, there is no misalignment between the multiple first laminates Xa and between the ceramic plate 21 and the metal plate 60 that constitute the first laminate Xa. In this way, if the jig is removed before the joining process, there is no need to consider the heat resistance of the material that constitutes the enclosing jig 5. This allows for a high degree of freedom in material selection. Examples of materials that can be used to constitute the enclosing jig 5 include polyethylene (e.g., high-density polyethylene), polypropylene, polyvinyl chloride, AS resin, acrylic resin, A2017 (duralumin), and A5052 (aluminum alloy). These materials have the advantage of being highly processable.

In a modified example, the enclosing jig 5 may be introduced into the heating furnace 8 together with the second laminate XA while the enclosing jig 5 holds the second laminate XA without removing the enclosing jig 5. When the enclosing jig 5 is introduced into the heating furnace 8, the enclosing jig 5 is made of a heat-resistant material. Such materials include carbon-based materials, boron nitride, iron-based S45C and SS400, stainless steel-based SUS304 and SUS303, and cemented carbide. Carbon-based materials include carbon graphite, C/C composites, glassy carbon, etc. Cemented carbide includes those containing tungsten carbide as the main component.

In the joining process, as shown in FIG. 15, the second laminate XA is introduced into the heating furnace 8 while being held under pressure by the pressure device 7. The heating furnace 8 is equipped with a heater 8a. The heater 8a heats the inside of the heating furnace 8 to a temperature at which the metal plate 60 and the ceramic plate 21 are joined by the joint. For example, if the metal plate 60 is a copper material, the inside of the heating furnace 8 is heated to 600°C to 900°C. If the metal plate 60 is an aluminum plate, the inside of the heating furnace 8 is heated to 550°C to 650°C. The coating layer 12 containing the brazing material melts at this atmospheric temperature, and becomes the joint 40 that joins the metal plate 60 and the ceramic plate 21 by cooling and solidifying after heating. As the metal plate 60 is heated in the heating furnace 8, the temporary fixing material 11 that temporarily fixed the metal plate 60 to the support plate TP disappears by volatilization, etc.

The multiple first laminates Xa that constituted the second laminate XA are each turned into an aggregate substrate 200, for example, as shown in FIG. 3, through a bonding process. The aggregate substrate 200 removed from the heating furnace 8 includes a ceramic plate 21 and multiple metal plates 60 bonded to the ceramic plate 21. Each of the multiple metal plates 60 is bonded to the ceramic plate 21 by a bonding portion 40. Here, the temporary fixing material 11 that fixed the metal plate 60 to the support plate TP has disappeared inside the heating furnace 8. Therefore, the support plate TP can be easily removed from the aggregate substrate 200, as shown in FIG. 16.

After removing the support plate TP, the collective substrate 200 is divided along the division lines SL1 and SL2. Then, a finishing process is performed as necessary to obtain a plurality of independent bonded bodies 100. Although not shown in FIG. 16, the entire peripheral portion of the main surface of the metal plate 60 in the collective substrate 200 opposite the ceramic plate 21 side is covered with the creeping portion 46 as in FIG. 1 and FIG. 2. For example, before dividing the collective substrate 200 along the division lines SL1 and SL2, the dimensions of the metal plate 60 and the width L of the creeping portion 46 may be detected using image recognition technology to perform a quality inspection of the collective substrate 200. In this way, after division, the bonded bodies may be sorted into those whose dimensions of the metal plate 60 or the width L of the creeping portion 46 meet a standard and those whose dimensions do not meet a standard. The standard may be a numerical range for the dimensions of the metal plate 60 and the width L of the creeping portion 46.

In the above manufacturing method, the assembly substrate 200 and the joint body 100 can be manufactured by mounting a metal plate obtained by punching onto a multi-piece ceramic plate. This mounting method allows the assembly substrate 200 and the joint body 100 to be obtained efficiently. In this manufacturing method, the metal plate is temporarily fixed to the support plate while being aligned using a first alignment jig (lattice jig 3), and the support plate (metal plate) and the ceramic plate are aligned using a second alignment jig (enclosure jig 5) and stacked to obtain the first laminate Xa (second laminate XA). This makes it possible to improve the alignment accuracy when joining the metal plate and the ceramic plate. Then, this first laminate Xa (second laminate XA) is heated while being pressurized by the pressure device 7. This makes it difficult for the coating layer and the metal plate to shift from each other.

In this way, a joint 40 can be formed having a creeping up portion 46 that covers the entire peripheral portion of the second main surface 60A of the metal plate 60 opposite the first main surface 60B on the ceramic plate 20 side. The joint 100 having such a joint 40 can perform highly accurate alignment when manufacturing semiconductor devices such as power modules by detecting the creeping up portion 46 using an image recognition device. In addition, the dimensions of the metal plate 60 can be measured with high accuracy. Therefore, the joint 100 and the assembly substrate 200 are extremely useful as components for manufacturing semiconductor devices such as highly reliable power modules.

In the above-mentioned example of the manufacturing method, the aggregate substrate 200 is manufactured, but the present invention is not limited to this. For example, an aggregate substrate different from the aggregate substrate 200 may be manufactured. Also, by using a ceramic plate 20 instead of the multi-piece ceramic plate 21 and performing the same alignment as when manufacturing the aggregate substrate 200 using the lattice jig 3 and the enclosure jig 5, the bonded body 100 may be manufactured without manufacturing the aggregate substrate 200. The first positioning jig is not limited to a lattice jig, and may be any jig that can improve the alignment accuracy when the metal plate is temporarily fixed. The second positioning jig is also not limited to an enclosure jig, and may be any jig that can improve the alignment accuracy when stacking the metal plate and the ceramic plate.

The manufacturing method of the joined body 100 and the collective substrate 200 is not limited to the above. It is not necessary to use all of the temporary fixing material, the first alignment jig, and the second alignment jig, and the joined body 100 and the collective substrate 200 may be manufactured using at least one of them. Also, the joined body 100 and the collective substrate 200 may be manufactured using an alignment jig of a different form.

The bonded body obtained by the above-mentioned manufacturing method may be used to manufacture a power module as shown in Figure 4. The power module may be manufactured by mounting a semiconductor element on the bonded body using solder and wire bonding, etc., housing the bonded body and the semiconductor element in the housing space of a case, and then sealing with resin. In this case, an image recognition device is used to image-recognize the creeping portion, and the metal plate and bonded body are aligned based on this, thereby efficiently manufacturing a highly reliable power module.

Although the embodiments of the present disclosure have been described above, the present disclosure is in no way limited to the above-described embodiments. For example, the structures and shapes of the metal plates and joints joined to each of the pair of main surfaces of the ceramic plate may be different from each other. Furthermore, the ceramic plate is not limited to one obtained by dividing an aggregate substrate.

The contents of this disclosure will be explained in more detail with reference to examples and comparative examples, but this disclosure is not limited to the following examples.

Example 1
[Preparation of aggregate substrate and bonded body]
The copper base material was punched with a die to obtain 24 copper plates (material: oxygen-free copper, size: length x width x thickness = 17 mm x 38 mm x 1.2 mm). The sides of these copper plates were composed of cut surfaces. A silicon nitride ceramic plate (silicon nitride plate, thickness: 0.25 mm) and a brazing material were prepared.

A brazing filler metal containing Ag, Sn, and _TiH2 was prepared. The brazing filler metal contained 3 parts by mass of Sn and 3.5 parts by mass of _TiH2 per 100 parts by mass of Ag. This brazing filler metal did not contain Cu.

The main surface of the ceramic plate was divided into 24 separate regions by scribe lines. A brazing filler metal was applied to each region by screen printing to form a coating layer. The coating area of the coating layer was the same as the area of the main surface of the copper plate to be joined to the ceramic plate. In addition, the coating layer had a thin coating portion in the center and a thick coating portion at the end (around the thin coating portion) as shown in Figure 11. The thickness of the thick coating portion was 1.5 times that of the thin coating portion. In addition, the width of the thick coating portion surrounding the thick coating portion was constant at 1.5 mm. The amount of brazing filler metal applied when forming the thick coating portion and the thin coating portion was as shown in Table 1.

A carbon plate was prepared as a support plate. Adhesive tape was applied to 24 places on the carbon plate to create a temporary fixing material. These adhesive tapes were applied at positions corresponding to the positions of the coating layer on the main surface of the ceramic plate. 24 copper plates were temporarily fixed onto the carbon plate with the temporary fixing material while being positioned using a grid jig 3 as shown in Figure 7. As shown in Figure 12, the ceramic plate and carbon plate were laminated so that the copper plate and the coating layer faced each other while being aligned using an enclosure jig 5. At this time, the copper plates were laminated so that the burrs were on the coating layer side and the sagging was on the carbon plate side.

The laminate was heated in a vacuum (1.0×10 ⁻³ Pa) at 790° C. for 1 hour while being pressurized at 0.015 MPa using a pressure device as shown in FIG. 14. In this way, an assembly substrate was obtained in which 24 copper plates were bonded to the ceramic plate via a bonding layer containing a brazing material component. Then, electroless plating was performed using a Ni—P plating solution (phosphorus concentration: 8 to 12 mass%) to form an assembly substrate (multiple-piece circuit substrate) having a plating film on the copper plate. The assembly substrate was divided along the scribe line to obtain 24 bonded bodies. The size of the ceramic plate of one bonded body was length×width×thickness=20 mm×41 mm×0.25 mm.

(Examples 2 and 3)
A joint was obtained in the same manner as in Example 1, except that a punched copper plate having the thickness shown in Table 1 was used.

Example 4
A bonded body was obtained in the same manner as in Example 2, except that no grid jig was used when temporarily fixing the 24 copper plates on the carbon plate with the temporary fixing material.

Example 5
A bonded body was obtained in the same manner as in Example 3, except that no enclosing jig for alignment was used when laminating the ceramic plate and the carbon plate with the copper plate and the coating layer facing each other.

Example 6
A joint was obtained in the same manner as in Example 1, except that the coating amount when forming the thick coating portion at the end of the coating layer was as shown in Table 2.

(Example 7)
A joint was obtained in the same manner as in Example 2, except that the coating amount when forming the thick coating portion at the end of the coating layer was as shown in Table 2.

(Example 8)
A joint was obtained in the same manner as in Example 3, except that the coating amount when forming the thick coating portion at the end of the coating layer was as shown in Table 2.

(Comparative Example 1)
A bonded body was obtained in the same manner as in Example 3, except that a grid jig and an enclosure jig were not used. That is, in the same manner as in Example 3, a brazing material was applied to each partitioned area of the main surface of the ceramic plate by screen printing to form a coating layer. A copper plate was laminated on this coating layer so that the burr was on the coating layer side and the sagging was on the carbon plate side to obtain a laminate. An aggregate substrate and a bonded body were obtained in the same manner as in Example 3, except that the above-mentioned laminate was used as the laminate to be pressed by the pressing device as shown in FIG.

(Comparative Example 2)
A joint was obtained in the same manner as in Example 3, except that the coating layer had no thick or thin coating portions and was of a uniform thickness. That is, the coating layer had no thick or thin coating portions and was of a uniform thickness. The amount of brazing material applied when forming the coating layer was as shown in Table 2.

[Evaluation of the conjugate]
<Whether or not there is a climbing part>
In each of the joints in the Examples and Comparative Examples, whether or not the periphery of the main surface of the metal plate was covered with a joint containing a brazing material component was visually evaluated according to the following criteria. The results are shown in Tables 1 and 2. The following numerical values (%) are ratios based on the entire periphery length of the main surface of the metal plate as the reference (100%).
A: The entire peripheral portion of the main surface of the metal plate is covered with the joint.
B: 95% or more and less than 100% of the periphery of the main surface of the metal plate is covered with the joint.
C: Only a portion of less than 95% of the periphery of the main surface of the metal plate is covered with the joint.
D: The peripheral portion of the main surface of the metal plate is not covered at all by the joint.

<Measurement of width L of the rising part>
The width L of the creeping portion covering the peripheral portion of the main surface of the metal plate was measured using a photograph taken under magnification with an optical microscope. The maximum and minimum values of the width L were determined by visually determining the positions where the width was maximum and minimum, and photographs of the periphery of these positions were taken with an optical microscope, and the maximum and minimum values of the width L were measured using the photographs. The maximum and minimum values of the width L were as shown in Tables 1 and 2. The difference between the maximum and minimum values was as shown in Tables 1 and 2.

The average value of width L was calculated by measuring the width L of the rising part at 20 randomly selected points and taking the arithmetic average of the measured values. The average values of width L are shown in Tables 1 and 2.

<Evaluation of location identification using image recognition>
Using an image dimension measuring machine, the shortest distance between each side of 24 metal plates placed on a ceramic plate and the outer edge of the ceramic plate was measured. Measurements were performed at 20 points on each side of each metal plate. The accuracy of identifying the position of the metal plate by image recognition was evaluated according to the following criteria by comparing the shortest distance actually measured (actual measurement value a) with the shortest distance measured using the image dimension measuring machine (measurement value b).
A: The image dimension measuring device was able to accurately measure the shortest distance from the outer edge of the ceramic plate to each metal plate. In other words, the actual measurement value a and the measurement value b were consistent for all 24 metal plates.
B: Of the 24 metal plates, the shortest distance of one or more metal plates could not be accurately measured by the image dimension measuring device. In other words, the position of the metal plate could not be correctly recognized, and there was one or more metal plates for which the actual measurement value a did not match the measured value b.

As shown in Tables 1 and 2, in the joints of Examples 1 to 8, which were produced by increasing the alignment accuracy using either a temporary fixing material, a lattice jig, or an enclosure jig, and by making the ends of the brazing material coating layer thicker than the center, a creep-up portion was formed that covered the entire peripheral portion of the main surface of the metal plate. The metal plates of these joints can be image-recognized with high accuracy, and alignment and dimensional measurement can be performed with high accuracy. On the other hand, in Comparative Example 1, which did not use any temporary fixing material, a lattice jig, or an enclosure jig, and Comparative Example 2, in which the thickness of the brazing material coating layer was made uniform, neither was able to form a creep-up portion that covered the entire peripheral portion of the main surface of the metal plate. In Comparative Example 1, the alignment accuracy between the copper plate and the coating layer was low, and the positions of the two were misaligned, which is thought to have led to the formation of a creep-up portion that covered only a part of the peripheral portion of the main surface of the metal plate. The joints of Comparative Examples 1 and 2 have a higher proportion of metal plates whose positions cannot be accurately identified by image recognition than Examples 1 to 8. For this reason, the joints of Comparative Examples 1 and 2 are considered to have inferior positioning accuracy compared to Examples 1 to 8.

The present disclosure provides a bonded body and a manufacturing method thereof that can be aligned or measured with high precision using image recognition technology. The present disclosure also provides an assembly substrate that can efficiently obtain such a bonded body. The present disclosure also provides a highly reliable power module by using such a bonded body.

3: Lattice jig, 5: Enclosure jig, 7: Pressure device, 8: Heating furnace, 8a: Heater, 11: Temporary fixing material, 12: Coating layer, 12A: Thick coating portion, 12B: Thin coating portion, 20: Ceramic plate, 20A, 20B, 21A, 21B, 60A, 60B: Main surface, 21: Ceramic plate, 31: Frame portion, 31a: Vertical wall portion, 31b: Horizontal wall portion, 32: Hole portion, 32 a...corner portion, 32b...gap forming portion, 32x...corner portion, 33...handle portion, 40...joint portion, 44...skirt portion, 44S...inclined surface, 45...outer edge, 46...creeping portion, 50...contact wall portion, 51...dividing wall portion, 51, 52...dividing wall portion, 51m...corner portion, 52...dividing wall portion, 52c...end portion, 52m...corner portion, 53...adjustment portion, 53a...slit , 53b...engagement receiving portion, 54...screw portion, 54a...shaft portion, 54b...head portion, 55...screw hole, 60, 60a, 61...metal plate, 62...side, 64...corner portion, 65...end portion, 71...base, 72...column portion, 73...cover plate, 74...elastic body, 75...pressure plate, 76...nut, 80...semiconductor element, 81, 82...solder, 83...electrode, 84...metal wire, 86...housing, 90...base plate, 92...cooling fin, 93...screw, 94...grease, 95...resin, 100, 101...bonded body, 200...aggregate substrate, 300...power module, DR...partition area, L...width, SL1, SL2...partition line, Sp...gap, TP...support plate, Xa...first stack, XA...second stack, Xb...corner portion.

Claims

A ceramic plate, a metal plate, and a joint portion that joins the ceramic plate and the metal plate and contains a brazing material component,
The joint has a creeping portion that covers the entire peripheral portion of a second main surface of the metal plate opposite to a first main surface on the ceramic plate side.
The joint according to claim 1, in which the creeping portion is used to identify the position of the joint.
The bonded body according to claim 1 or 2, wherein the minimum width L of the rising portion on the second main surface is 0.1 mm or more.
The joint body according to claim 1 or 2, wherein the maximum width L of the raised portion on the second main surface is 2.0 mm or less.
The joint body according to claim 1 or 2, wherein the thickness of the metal plate is 0.5 mm or more.
The multi-cavity ceramic plate includes a plurality of metal plates, and a plurality of bonding portions that bond the ceramic plate and the plurality of metal plates and that contain a brazing material component;
An aggregate substrate, wherein at least one of the plurality of joints has a creeping portion covering the entire peripheral portion of a second main surface of the metal plate joined at the joint, the second main surface being opposite to the first main surface on the ceramic plate side.
a coating step of coating a brazing material on a main surface of the ceramic plate to form a coating layer;
a lamination step of laminating the coating layer and the metal plate so that the metal plate and the coating layer face each other to produce a laminate;
a joining step of heating the laminate to join the metal plate and the ceramic plate with a joint portion containing a brazing material component,
A method for manufacturing a joint, wherein, in the coating process, the thickness of the end portion of the coating layer is made thicker than that of the center portion, and, in the joining process, the joint is formed having a creeping portion that covers the entire peripheral portion of a second main surface of the metal plate opposite to a first main surface on the ceramic plate side.
the ceramic plate is a first ceramic plate for multiple cavity molding,
In the coating step, a plurality of the coating layers are provided on the main surface of the first ceramic plate,
In the lamination step, the first ceramic plate and the metal plates are laminated so as to sandwich the coating layers therebetween to prepare the laminate;
The method for producing a bonded body according to claim 7 , further comprising the step of dividing the first ceramic plate into a plurality of bonded bodies after the bonding step.
A power module comprising: the bonded body according to claim 1 or 2; and a semiconductor element electrically connected to the metal plate of the bonded body.