Multilayer metal junction ceramic substrate and manufacturing method therefor

Abstract

A multilayer metal junction ceramic substrate according to an embodiment of the present invention is a multilayer metal junction ceramic substrate in which a plurality of metal layers and a plurality of ceramic substrates are alternately laminated with a junction layer therebetween, wherein a first ceramic substrate, which is any one of the plurality of ceramic substrates, has a Cu block inserted thereinto, and the Cu block may electrically connect a first metal layer and a second metal layer laminated on the upper and lower sides of the first ceramic substrate.

Description

Multilayer metal-bonded ceramic substrate and manufacturing method thereof

[0001] The present invention relates to a multilayer metal-bonded ceramic substrate and a manufacturing method thereof, and more particularly, to a multilayer metal-bonded ceramic substrate and a manufacturing method thereof that can stably conduct current without being destroyed even when high voltage and high current are conducted.

[0002] Multilayer ceramic substrates are used as composite components that combine active components such as semiconductor IC chips with passive components such as capacitors, inductors, and resistors, or as simple semiconductor IC packages, and are widely used to construct various electronic components such as PA module substrates, RF diode switches, filters, chip antennas, various package components, and composite devices.

[0003] These multilayer ceramic substrates typically employ conductive via structures for interlayer electrical connection.

[0004] Conductive vias are formed by preparing a ceramic substrate forming the first layer of a multilayer circuit board, such as a multilayer ceramic substrate, and then forming a predetermined via hole in the ceramic substrate. Then, a conductive material such as silver is filled into the via hole to form a via electrode.

[0005] These via electrodes have the problem of electrical or thermal destruction due to high current density when high-power power conversion is performed.

[0006] The matters described in the background art above are intended to help understand the background of the invention and may include matters that are not publicly disclosed prior art.

[0007] The present invention has been invented to improve the above-mentioned problems, and the problem to be solved by the present invention is to provide a multilayer metal-bonded ceramic substrate and a method for manufacturing the same, in which a plurality of Cu blocks are inserted into a ceramic substrate for electrical connection between layers to ensure stable current conduction.

[0008] In order to achieve the above-described purpose, a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention is a multilayer metal-bonded ceramic substrate in which a plurality of metal layers and a plurality of ceramic substrates are alternately laminated with a bonding layer therebetween, and may include a first ceramic substrate having an insertion hole formed therein, a first metal layer laminated on an upper portion of the first ceramic substrate, a second metal layer laminated on a lower portion of the first ceramic substrate, and a Cu block inserted into the insertion hole of the first ceramic substrate and electrically connecting the first metal layer and the second metal layer.

[0009] In addition, the multilayer metal-bonded ceramic substrate according to an embodiment of the present invention may further include a second ceramic substrate laminated on a lower portion of the second metal layer, and a third metal layer laminated on a lower portion of the second ceramic substrate.

[0010] The second metal layer may include an intermediate metal layer bonded to a plurality of Cu blocks, and a border metal layer arranged to surround the intermediate metal layer. Here, the intermediate metal layer and the border metal layer may be spaced apart from each other and insulated from each other.

[0011] An edge of the first metal layer may be spaced apart from an edge of the first ceramic substrate by a first gap.

[0012] The edge of the third metal layer may be spaced apart from the edge of the second ceramic substrate by a second gap.

[0013] A first gap between an edge of the first metal layer and an edge of the first ceramic substrate, and a second gap between an edge of the third metal layer and an edge of the second ceramic substrate may be formed to be larger than a third gap between the intermediate metal layer and the edge metal layer.

[0014] Multiple Cu blocks can have a silver (Ag) plating film formed on their surfaces.

[0015] The plurality of bonding layers may be a multilayer structure including a Ti layer, a Cu layer, and an Ag layer.

[0016] The first metal layer can be divided into a plurality of metal patterns.

[0017] The area occupied by the Cu block on one side of the first ceramic substrate can be formed in a range of 10% to 90% based on the area of ​​the lower surface of the metal pattern of the first metal layer connected to the Cu block.

[0018] A method for manufacturing a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention may include a step of preparing a first ceramic substrate having an insertion hole formed therein, a step of laminating a second metal layer on a lower portion of the first ceramic substrate and inserting a Cu block into the insertion hole, a step of laminating a first metal layer on an upper portion of the first ceramic substrate and the Cu block, and a step of brazing the first metal layer, the first ceramic substrate, the Cu block, and the second metal layer.

[0019] In addition, the method for manufacturing a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention may further include a step of laminating a second ceramic substrate on a lower portion of a second metal layer, a step of laminating a third metal layer on a lower portion of the second ceramic substrate, and a step of brazing the second metal layer, the second ceramic substrate, and the third metal layer.

[0020] After the step of brazing the first metal layer, the first ceramic substrate, the plurality of Cu blocks, and the second metal layer, the step of etching the second metal layer to separate it into an intermediate metal layer bonded to the plurality of Cu blocks and a border metal layer arranged to surround the intermediate metal layer may be further included.

[0021] A method for manufacturing a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention may further include a step of forming a circuit pattern on a first metal layer and a third metal layer.

[0022] In the step of forming a circuit pattern, each of the first metal layer and the third metal layer may be formed such that an edge portion thereof is etched to leave a gap with the edge of an adjacent ceramic substrate.

[0023] The step of preparing a first ceramic substrate having an insertion hole inserted therein may include a step of forming a first bonding layer on an upper surface of the first ceramic substrate.

[0024] In the step of inserting the Cu block, a second bonding layer may be interposed between the first ceramic substrate and the second metal layer.

[0025] In the step of inserting the Cu block, a silver (Ag) plating film can be formed on the surface of the Cu block.

[0026] In the step of inserting the Cu block, the Cu block is inserted so that its side surface leaves a gap with the inner surface of the insertion hole, and in the step of brazing the first metal layer, the first ceramic substrate, the Cu block, and the second metal layer, the Cu block can expand so as to come into contact with the inner surface of the insertion hole.

[0027] According to the multilayer metal-bonded ceramic substrate of the present invention and the manufacturing method thereof, by connecting the first metal layer and the second metal layer with Cu blocks inserted into the first ceramic substrate, even when high voltage and high current are passed, not only is the conductivity of the Cu block itself excellent, but also the contact area between the Cu block and the first ceramic substrate is large, so that the first ceramic substrate is not destroyed and stable current can be passed, electrical loss can be reduced, and heat dissipation is also effective.

[0028] In addition, according to the multilayer metal-bonded ceramic substrate of the present invention and the manufacturing method thereof, the first ceramic substrate can implement various circuits by including both a current-conducting region by the Cu block and an insulation region by the ceramic since the portion where the Cu block is not inserted is in an insulating state.

[0029] In addition, according to the multilayer metal-bonded ceramic substrate of the present invention and the manufacturing method thereof, the first metal layer, the first and second Cu blocks inserted into the first ceramic substrate, and the intermediate metal layer of the second metal layer can be electrically connected to form a high current loop, thereby reducing electrical loss.

[0030] In addition, according to the multilayer metal-bonded ceramic substrate of the present invention and the manufacturing method thereof, since the edge metal layer in the second metal layer is insulated from the middle metal layer and surrounds the edge of the middle metal layer, it is possible to shield the electromagnetic field generated in the high current loop and increase the interlayer bonding strength.

[0031] FIG. 1 is a perspective view illustrating a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention.

[0032] FIG. 2 is an exploded perspective view illustrating a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention.

[0033] Figure 3 is a cross-sectional view taken along line A-A' of Figure 1.

[0034] FIG. 4 is a plan view illustrating a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention.

[0035] FIG. 5 is a bottom view illustrating a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention.

[0036] FIG. 6 is a bottom view illustrating a second metal layer in a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention.

[0037] Figure 7 is a flow chart illustrating a method for manufacturing a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention.

[0038] Figure 8 is a schematic diagram illustrating a method for manufacturing a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention.

[0039] FIG. 9 is a bottom view illustrating a step of etching a second metal layer to separate it into an intermediate metal layer and a border metal layer in a method for manufacturing a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention.

[0040] Fig. 10 is a cross-sectional view illustrating a multilayer metal-bonded ceramic substrate according to a comparative example.

[0041] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0042] These examples are provided to more fully illustrate the present invention to those skilled in the art. The following examples may be modified in various ways, and the scope of the present invention is not limited to the examples described below. Rather, these examples are provided to further faithfully and completely convey the spirit of the present invention.

[0043] The terms used herein are used to describe specific embodiments and are not intended to limit the present invention. Furthermore, the singular forms used herein may include the plural forms, unless the context clearly dictates otherwise.

[0044] In the description of the embodiments, when each layer (film), region, pattern or structure is described as being formed "on" or "under" the substrate, each layer (film), region, pad or pattern, "on" and "under" include both being formed "directly" or "indirectly" through another layer. In addition, the reference for above or below each layer is, in principle, based on the drawing.

[0045] The drawings are intended solely to facilitate understanding of the invention and should not be construed as limiting the scope of the invention. Furthermore, relative thicknesses, lengths, and sizes in the drawings may be exaggerated for convenience and clarity of explanation.

[0046] As illustrated in FIG. 1, a multilayer metal-bonded ceramic substrate (1) according to an embodiment of the present invention may have a structure in which a plurality of metal layers (110, 120, 130) and a plurality of ceramic substrates (210, 220) are alternately laminated. Here, the plurality of metal layers (110, 120, 130) may be configured to include a first metal layer (110), a second metal layer (120), and a third metal layer (130), and the plurality of ceramic substrates (210, 220) may be configured to include a first ceramic substrate (210) and a second ceramic substrate (220).

[0047] Referring to FIG. 2, the first metal layer (110) may be formed as a metal pattern for mounting a semiconductor chip. The first metal layer (110) may be made of one of Cu, a Cu alloy (such as CuMo), and Al, and may have a thickness of 0.3T.

[0048] The first ceramic substrate (210) is disposed under the first metal layer (110), and may be made of any one of alumina (Al2O3), AlN, zirconia-reinforced alumina (ZTA), and Si3N4, and may have a thickness of 0.25T. The first ceramic substrate (210) may have a plurality of insertion holes (211) formed therein, and a plurality of Cu blocks (101) may be inserted into the plurality of insertion holes (211). The plurality of Cu blocks (101) are for electrically connecting the first metal layer (110) and the second metal layer (120) laminated on the upper and lower portions of the first ceramic substrate (210), and may be formed by processing Cu, which is an electrically conductive metal material, into a block shape. In the present embodiment, an example in which the first Cu block (101a) and the second Cu block (101b) are provided is illustrated, but the number and positions of the Cu blocks may be changed depending on the designed circuit structure.

[0049] The second metal layer (120) is disposed on the lower side of the first ceramic substrate (210), and may be made of one of Cu, a Cu alloy (CuMo, etc.), and Al, and may have a thickness of 0.3T. The second metal layer (120) may include an intermediate metal layer (121) bonded to the Cu block (101), and a border metal layer (122) disposed to surround the intermediate metal layer (121). Here, the border metal layer (122) is bonded to the edge region of the first ceramic substrate (210), and may be formed in a square ring type. The intermediate metal layer (121) and the border metal layer (122) may be spaced apart from each other at a distance and insulated from each other. Here, the distance between the intermediate metal layer (121) and the border metal layer (122) may be 150㎛.

[0050] As will be described later, the second metal layer (120) can be bonded to the lower portion of the first ceramic substrate (210) in a flat form in which the intermediate metal layer (121) and the border metal layer (122) are not separated, and after the first metal layer (110) and the second metal layer (120) are bonded to the upper and lower portions of the first ceramic substrate (210) to form a bonded body in the first place, the second metal layer (120) can be separated into the intermediate metal layer (121) and the border metal layer (122) by etching a portion of the edge area into a frame shape.

[0051] The second ceramic substrate (220) is disposed below the second metal layer (120), and may be made of any one of alumina (Al2O3), AlN, zirconia-reinforced alumina (ZTA), and Si3N4, and may have a thickness of 0.25T. The second ceramic substrate (220) may be provided in a flat plate shape.

[0052] The third metal layer (130) is disposed on the lower portion of the second ceramic substrate (220), and may be made of one of Cu, a Cu alloy (CuMo, etc.), and Al, and may have a thickness of 0.3T. The third metal layer (130) may be formed to have a circuit pattern, and may be formed in a flat shape to increase the heat dissipation area with a heat sink (not shown).

[0053] Referring to FIG. 3, a multilayer metal-bonded ceramic substrate (1) according to an embodiment of the present invention may have a structure in which a plurality of metal layers (110, 120, 130) and a plurality of ceramic substrates (210, 220) are alternately laminated with a bonding layer (310, 320, 330, 340) therebetween. Specifically, a first metal layer (110) may be laminated on top of a first ceramic substrate (210) with a first bonding layer (310) therebetween, and a second metal layer (120) may be laminated on the lower portion of the first ceramic substrate (210) with a second bonding layer (320) therebetween. In addition, a second ceramic substrate (220) may be laminated on the lower portion of the second metal layer (120) with a third bonding layer (330) therebetween, and a third metal layer (130) may be laminated on the lower portion of the second ceramic substrate (220) with a fourth bonding layer (340) therebetween. In this way, the multilayer metal-bonded ceramic substrate (1) has a structure in which a first metal layer (110), a first ceramic substrate (210), a second metal layer (120), a second ceramic substrate (220), and a third metal layer (130) are laminated with a bonding layer (310, 320, 330, 340) interposed therebetween and bonded via the bonding layer (310, 320, 330, 340). It is preferable that the multilayer metal-bonded ceramic substrate (1) be composed of at least four layers.

[0054] The first to fourth bonding layers (310, 320, 330, 340) may be formed of one selected from Ag, Cu, and AgCu, or a structure in which two or more thereof are mixed. Ag, Cu, and AgCu alloys have high thermal conductivity and facilitate heat dissipation. Preferably, the first to fourth bonding layers (310, 320, 330, 340) may be formed as a thin film having a multilayer structure. For example, the first bonding layer (310) may include a Ti layer formed on the upper surface of the first ceramic substrate (210), a Cu layer formed on the Ti layer, and an Ag layer formed on the Cu layer. Here, the Ti layer has good wettability and can increase the adhesion of the Cu layer and the Ag layer. These first to fourth bonding layers (310, 320, 330, 340) may be formed by a method such as deposition, paste printing, or a photo process.

[0055] Meanwhile, a silver (Ag) plating film (102) may be formed on the surface of the Cu block (101). The silver plating film (102) may be formed on the upper and lower surfaces or the entire surface of the Cu block (101) through a thin film process, filler plating, or the like. The Cu block (101) has a silver plating film (102) formed on the surface, and the first bonding layer (310) formed on the surface of the first ceramic substrate (210) is formed as a multilayer including a Ti layer, a Cu layer, and an Ag layer, so that both the Cu block (101) and the first bonding layer (310) have a structure in which an Ag layer is formed on a Cu layer. Accordingly, a Cu block (101) having a silver plating film (102) formed thereon is inserted into an insertion hole (211) of a first ceramic substrate (210) having a first bonding layer (310) formed thereon, and when a first metal layer (110) is laminated in this state and heat and pressure are applied, the first metal layer (110) can be bonded to the upper surface of the Cu block (101) and the first ceramic substrate (210) via the silver plating film (102) and the first bonding layer (310).

[0056] Referring to Fig. 10, in the case of a multilayer metal-bonded ceramic substrate (1') according to a comparative example, a plurality of via holes (h) are formed in the first ceramic substrate (210') to electrically connect the first metal layer (110') and the second metal layer (120') laminated on the upper and lower portions of the first ceramic substrate (210'), and a metal filler (m) such as Ag, Cu, or AgCu may be filled inside the via holes (h). At this time, the number of via holes (h) is formed to be approximately 500 or more, and the width of each via hole (h) is formed to be approximately 120 ㎛. In the case of an automobile, since high-output power conversion is performed, there is a problem that when a strong voltage of approximately 650 V or more is applied, the portion of the first ceramic substrate (210') on which the plurality of via holes (h) are formed is electrically or thermally destroyed due to the high current density.

[0057] Accordingly, the present invention is characterized by inserting a Cu block (101) into a plurality of insertion holes (211) formed in a portion of a first ceramic substrate (210), and electrically connecting a first metal layer (110) and a second metal layer (120) bonded to the upper and lower portions of the first ceramic substrate (210) through the Cu block (101). Here, since the Cu block (101) has a thermal expansion coefficient of 17 ppm / ℃, a gap of about 150 ㎛ can be designed when designing the gap with the insertion hole (211) in consideration of thermal expansion occurring during the brazing process.

[0058] When the first metal layer (110) and the second metal layer (120) are connected by a Cu block (101) inserted into the first ceramic substrate (210), even if a high voltage and high current are passed through, not only is the conductivity of the Cu block (101) itself excellent, but also the contact area between the Cu block (101) and the first ceramic substrate (210) is large, so that the first ceramic substrate (210) is not destroyed and stable current can be passed through, electrical loss can be reduced, and heat dissipation is also effective. In addition, since the first ceramic substrate (210) is in an insulated state in a part where the Cu block (101) is not inserted, it can include both a current-conducting area by the Cu block (101) and an insulation area by the ceramic.

[0059] Referring to FIG. 4, the first metal layer (110) may be provided by being divided into a plurality of metal patterns. At this time, the first to third metal patterns (111, 112, 113) may have a first semiconductor element (C1) and a second semiconductor element (C2) mounted thereon, the first Cu block (101a) may be connected to the first metal pattern (111), and the second Cu block (101b) may be connected to the fourth metal pattern (114). The first and second semiconductor elements (C1, C2) may be SiC, GaN, IGBT, etc. These first and second semiconductor elements (C1, C2) may be bonded to the upper surface of the first metal layer (110) by a bonding layer (not shown) including solder or silver paste.

[0060] The first semiconductor element (C1) may have a drain electrode bonded to a first metal pattern (111) and a source electrode bonded to a second metal pattern (112). The second semiconductor element (C2) may have a drain electrode bonded to a second metal pattern (112) and a source electrode bonded to a third metal pattern (113). At this time, power supplied to the drain electrode of the first semiconductor element (C1) may pass through the first metal pattern (111) and the first Cu block (101a) to the second metal layer (120), and again pass from the second metal layer (120) through the second Cu block (101b) to the fourth metal pattern (114). That is, the multilayer metal bonding ceramic substrate (1) may include a loop circuit structure in which power supplied to the first metal pattern (111) of the first metal layer (110) is connected to the intermediate metal layer (121) of the second metal layer (120) through the first Cu block (101a), and then transmitted to the fourth metal pattern (114) of the first metal layer (110) through the second Cu block (101b). In this way, the first and second Cu blocks (101a, 101b) inserted into the first metal layer (110), the first ceramic substrate (210), and the intermediate metal layer (121) of the second metal layer (120) may be electrically connected to form a high-current loop. Such a loop circuit structure may reduce loss, and the present invention may easily implement a desired circuit structure through the Cu block.

[0061] Meanwhile, since the border metal layer (122) surrounds the border of the middle metal layer (121) while being insulated from the middle metal layer (121), it is possible to shield the electromagnetic field generated in the high current loop. In addition, since the top surface of the border metal layer (122) of the second metal layer (120) is in contact with the first ceramic substrate (210) and the bottom surface is bonded to the second ceramic substrate (220), the area bonded to the first and second ceramic substrates (210, 220) can be increased compared to when only the middle metal layer (121) is present, thereby increasing the interlayer bonding strength.

[0062] Meanwhile, the area occupied by the Cu block (101) on one surface of the first ceramic substrate (210) of the first metal layer (110) may be formed in a range of 10% to 90% based on the area of ​​the lower surface of the metal pattern of the first metal layer (110) connected to the Cu block (101). For example, the area occupied by the first Cu block (101a) on one surface of the first ceramic substrate (210) may be formed in a range of 10% to 90% based on the area of ​​the lower surface of the first metal pattern (111) connected to the first Cu block (101a). If the area occupied by the Cu block (101) on one side of the first ceramic substrate (210) is less than 10% of the area of ​​the lower surface of the metal pattern of the first metal layer (110) connected to the Cu block (101), the electrical connection between the first metal layer (110) and the second metal layer (120) is not smooth, and if it exceeds 90%, the connection area of ​​the first metal layer (110) with the metal pattern becomes too wide, which may cause a short circuit. Therefore, it is preferable that the area occupied by the Cu block (101) on one side of the first ceramic substrate (210) be formed in a range of 10% or more and 90% or less of the area of ​​the lower surface of the metal pattern of the first metal layer (110) connected to the Cu block (101).

[0063] Referring to FIGS. 4 and 5, the edge of the first metal layer (110) may be spaced apart from the edge of the first ceramic substrate (210) by a first distance (d1), and the edge of the third metal layer (130) may be spaced apart from the edge of the second ceramic substrate (220) by a second distance (d2). Since the first metal layer (110) and the third metal layer (130) are exposed portions of the multilayer metal-bonded ceramic substrate (1), the side portions may be etched to form the edge portions with a distance for insulation in order to prevent short circuits with surrounding components. At this time, the edge of the first metal layer (110) may be side-etched to leave a first gap (d1) with the edge of the first ceramic substrate (210), which is an adjacent ceramic substrate, and the edge of the third metal layer (130) may be side-etched to leave a second gap (d2) with the edge of the second ceramic substrate (220), which is an adjacent ceramic substrate. As an example, the first gap (d1) and the second gap (d2) are 500 μm when the thicknesses of the first metal layer (110) and the third metal layer (130) are 0.3 t.

[0064] Referring to FIGS. 4 to 6, the first gap (d1) between the edge of the first metal layer (110) and the edge of the first ceramic substrate (210), and the second gap (d2) between the edge of the third metal layer (130) and the edge of the second ceramic substrate (220) may be formed to be larger than the third gap (d3) between the intermediate metal layer (121) and the edge metal layer (122). Since the second metal layer (120) is a portion where the first ceramic substrate (210) and the second ceramic substrate (220) are bonded to the upper and lower portions and are not exposed, the third gap (d3) may be formed to be smaller than the first gap (d1) and the second gap (d2). In this case, the third gap (d3) is 150 μm as an example.

[0065] Hereinafter, with reference to FIGS. 7 to 9, a method for manufacturing a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention will be described.

[0066] FIG. 7 is a flowchart illustrating a method for manufacturing a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention, FIG. 8 is a schematic diagram illustrating a method for manufacturing a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention, and FIG. 9 is a bottom view illustrating a step of etching a second metal layer to separate it into an intermediate metal layer and a border metal layer.

[0067] A method for manufacturing a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention comprises the steps of (S10) preparing a first ceramic substrate (210) having an insertion hole (211) formed therein, as illustrated in FIG. 7, a step of laminating a second metal layer (120) on the lower portion of the first ceramic substrate (210) and inserting a Cu block (101) into the insertion hole (211), a step of (S30) laminating a first metal layer (110) on the upper portion of the first ceramic substrate (210) and the Cu block (101), a step of brazing the first metal layer (110), the first ceramic substrate (210), the Cu block (101) and the second metal layer (120), and a step of laminating a second ceramic substrate (220) on the lower portion of the second metal layer (120) and laminating a third metal layer (130) on the lower portion of the second ceramic substrate (220). It can be configured to include a step (S50) and a step (S60) of brazing a second metal layer (120), a second ceramic substrate (220), and a third metal layer (130).

[0068] In the step (S10) of preparing a first ceramic substrate (210) in which an insertion hole (211) is formed, the insertion hole (211) can be formed by laser processing, etc.

[0069] The step (S10) of preparing a first ceramic substrate (210) in which an insertion hole (211) is formed may include a step of forming a first bonding layer (310) on the upper surface of the first ceramic substrate (210).

[0070] In the step of forming the first bonding layer (310), the first bonding layer (310) may have a structure in which one selected from Ag, Cu, and AgCu or two or more thereof are mixed. Ag, Cu, and AgCu alloys have high thermal conductivity and thus facilitate heat dissipation. Preferably, the first bonding layer (310) may be formed as a thin film having a multilayer structure. For example, the first bonding layer (310) may include a Ti layer formed on the upper surface of the first ceramic substrate (210), a Cu layer formed on the Ti layer, and an Ag layer formed on the Cu layer. Here, the Ti layer has good wettability and can increase the adhesion of the Cu layer and the Ag layer. This first bonding layer (310) may be formed on the upper surface of the first ceramic substrate (210) by a method such as deposition or paste printing.

[0071] The step (S10) of preparing a first ceramic substrate (210) in which insertion holes (211) are formed may further include a trimming step for removing burrs formed around a plurality of insertion holes (211) after the step of forming the first bonding layer (310).

[0072] In the step (S20) of laminating a second metal layer (120) on the lower portion of the first ceramic substrate (210) and inserting a Cu block (101) into the insertion hole (211), the second metal layer (120) may be provided in a flat plate shape, and a second bonding layer (320) may be formed on the upper surface. Accordingly, when the second metal layer (120) is laminated on the lower portion of the first ceramic substrate (210), the second bonding layer (320) may be interposed between the first ceramic substrate (210) and the second metal layer (120).

[0073] In the step (S20) of inserting a Cu block (101), a silver (Ag) plating film may be formed on the surface of the Cu block (101). The silver plating film (102) may be formed on the upper and lower surfaces or the entire surface of the Cu block (101) through a thin film process, filler plating, or other process.

[0074] In the step (S20) of inserting the Cu block (101), the Cu block (101) may be provided so that the side surface has a gap of about 150 μm with the inner surface of the insertion hole (211). That is, since the Cu block (101) has a thermal expansion coefficient of 17 ppm / ℃, the gap may be designed to have a gap of about 150 μm when designing the gap with the insertion hole (211) in consideration of the thermal expansion that occurs during the brazing process. In the step (S40) of brazing the first ceramic substrate (210), the Cu block (101), and the second metal layer (120), the Cu block (101) may expand so as to come into contact with the inner surface of the insertion hole (211).

[0075] The step (S30) of laminating a first metal layer (110) on top of a first ceramic substrate (210) and a Cu block (101) may be performed by laminating a second metal layer (120) on the lower side of the first ceramic substrate (210) and inserting a Cu block (101) having a silver plating film (102) formed thereon into an insertion hole (211) of the first ceramic substrate (210) while laminating the first metal layer (110).

[0076] The step (S40) of brazing the first metal layer (110), the first ceramic substrate (210), the Cu block (101), and the second metal layer (120) is performed by placing a laminate in which the first metal layer (110) and the second metal layer (120) are arranged on the upper and lower portions of the first ceramic substrate (210) into which the Cu block (101) is inserted, on a brazing jig, and applying heat and pressure at a brazing temperature of 850°C to 900°C, so that bonding can be formed through the bonding layers (310, 320) interposed between the respective layers, thereby forming a primary bonded body. At this time, since the Cu block (101) has a silver plating film (102) formed on the upper surface, and the first bonding layer (310) disposed on the upper surface of the first ceramic substrate (210) is formed as a multilayer including Ti / Cu / Ag, both the Cu block (101) and the first bonding layer (310) may have a structure in which an Ag layer is formed on the Cu layer. In addition, since the Cu block (101) has a silver plating film (102) formed on the lower surface, and the second bonding layer (320) disposed on the lower surface of the first ceramic substrate (210) is formed as a multilayer including Ti / Cu / Ag, both the Cu block (101) and the second bonding layer (320) may have a structure in which an Ag layer is formed on the Cu layer. Therefore, the first metal layer (110) may be brazed to the upper surface of the Cu block (101) and the first ceramic substrate (210) via the silver plating film (102) and the first bonding layer (310). Additionally, the second metal layer (120) can be brazed to the lower surface of the Cu block (101) and the first ceramic substrate (210) via the silver plating film (102) and the second bonding layer (320).

[0077] After the step (S40) of brazing the first metal layer (110), the first ceramic substrate (210), the Cu block (101), and the second metal layer (120), the step of etching the second metal layer (120) to separate it into an intermediate metal layer (121) bonded to a plurality of Cu blocks (101) and a border metal layer (122) arranged to surround the intermediate metal layer (121) may be further included. In the step (S40) of brazing the second metal layer (120), the second metal layer (120) may be bonded to the lower portion of the first ceramic substrate (210) in a flat plate shape in which the intermediate metal layer (121) and the border metal layer (122) are not separated. After the first metal layer (110) and the second metal layer (120) are bonded to the upper and lower portions of the first ceramic substrate (210) to form a bonded body in the first stage, in the step of separating with a border metal layer (122), a part of the edge area of ​​the second metal layer (120) may be cross-sectionally etched in a frame shape to separate it into an intermediate metal layer (121) and a border metal layer (122). Here, the border metal layer (122) is bonded to the edge area of ​​the first ceramic substrate (210) and may be formed in a square ring shape.

[0078] In the step (S50) of laminating a second ceramic substrate (220) on the lower portion of the second metal layer (120) and laminating a third metal layer (130) on the lower portion of the second ceramic substrate (220), a third bonding layer (330) may be formed on the upper surface of the second ceramic substrate (220). Therefore, when the second ceramic substrate (220) is laminated on the lower portion of the second metal layer (120), a third bonding layer (330) may be interposed between the second metal layer (120) and the second ceramic substrate (220). In addition, a fourth bonding layer (340) may be formed on the upper surface of the third metal layer (130). Therefore, when the third metal layer (130) is laminated on the lower portion of the second ceramic substrate (220), a fourth bonding layer (340) may be interposed between the second ceramic substrate (220) and the third metal layer (130).

[0079] The step (S60) of brazing the second metal layer (120), the second ceramic substrate (220), and the third metal layer (130) may be performed by laminating the second ceramic substrate (220) on the lower portion of the second metal layer (120), laminating the third metal layer (130) on the lower portion of the second ceramic substrate (220), and brazing the layers via a bonding layer (330, 340) interposed between the respective layers to ultimately manufacture a multilayer metal-bonded ceramic substrate (1). Here, the brazing temperature may be 850°C to 900°C.

[0080] In this way, the method for manufacturing a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention can form a bonded body in which a first metal layer (110) and a second metal layer (120) are brazed to the upper and lower portions of a first ceramic substrate (210), and then sequentially stack a second ceramic substrate (220) and a third metal layer (130) on the lower portion of the second metal layer (120) and braze once more to finally manufacture a multilayer metal-bonded ceramic substrate (1). That is, the method for manufacturing a multilayer metal-bonded ceramic substrate according to an embodiment of the present invention can form a ceramic substrate having a five-layer structure through two brazing processes.

[0081] After the step (S60) of bonding the second metal layer (120), the second ceramic substrate (220), and the third metal layer (130), a step of forming a circuit pattern on the first metal layer (110) and the third metal layer (130) may be further included. Although not illustrated in detail, the step of forming the circuit pattern may be performed by selectively removing the first metal layer (110) and the third metal layer (130) using a photolithography process to form the circuit pattern.

[0082] In the step of forming a circuit pattern, since the first metal layer (110) and the third metal layer (130) are exposed portions of the multilayer metal bonding ceramic substrate (1), the edges can be formed to have a gap for insulation by etching them to prevent short circuits with surrounding components. At this time, the edge of the first metal layer (110) can be side-etched to have a first gap (d1) with the edge of the first ceramic substrate (210), which is an adjacent ceramic substrate, and the edge of the third metal layer (130) can be side-etched to have a second gap (d2) with the edge of the second ceramic substrate (220), which is an adjacent ceramic substrate. As an example, the first gap (d1) and the second gap (d2) are 500 μm when the thickness of the first metal layer (110) and the third metal layer (130) is 0.3t.

[0083] In this way, the multilayer metal-bonded ceramic substrate and its manufacturing method according to an embodiment of the present invention connect the first metal layer (110) and the second metal layer (120) with the Cu block (101) inserted into the first ceramic substrate (210), so that high voltage and high current can be stably transmitted without destroying the first ceramic substrate (210), electrical loss can be reduced, and heat dissipation is also effective.

[0084] The above description is merely an illustrative illustration of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. A multilayer metal-bonded ceramic substrate in which multiple metal layers and multiple ceramic substrates are alternately laminated with a bonding layer in between, A first ceramic substrate having an insertion hole formed therein; A first metal layer laminated on top of the first ceramic substrate; A second metal layer laminated on the lower portion of the first ceramic substrate; and A multilayer metal-bonded ceramic substrate including a Cu block inserted into an insertion hole of the first ceramic substrate and electrically connecting the first metal layer and the second metal layer.

2. In paragraph 1, A second ceramic substrate laminated on the lower portion of the second metal layer; and A multilayer metal-bonded ceramic substrate further comprising a third metal layer laminated on the lower portion of the second ceramic substrate.

3. In paragraph 2, The second metal layer is, an intermediate metal layer bonded to the Cu block; and A multilayer metal-bonded ceramic substrate comprising a border metal layer arranged to surround the intermediate metal layer.

4. In paragraph 3, A multilayer metal-bonded ceramic substrate in which the intermediate metal layer and the border metal layer are spaced apart from each other and insulated from each other.

5. In paragraph 1, A multilayer metal-bonded ceramic substrate in which the edge of the first metal layer is spaced apart from the edge of the first ceramic substrate by a first gap.

6. In paragraph 2, A multilayer metal-bonded ceramic substrate in which the edge of the third metal layer is spaced apart from the edge of the second ceramic substrate by a second gap.

7. In paragraph 3, A first gap between the edge of the first metal layer and the edge of the first ceramic substrate, and a second gap between the edge of the third metal layer and the edge of the second ceramic substrate, A multilayer metal-bonded ceramic substrate formed to be larger than the third gap between the intermediate metal layer and the border metal layer.

8. In paragraph 1, The above Cu block is a multilayer metal-bonded ceramic substrate having a silver (Ag) plating film formed on the surface.

9. In paragraph 1, The above bonding layer is a multilayer metal bonding ceramic substrate having a multilayer structure including a Ti layer, a Cu layer, and an Ag layer.

10. In paragraph 1, A multilayer metal bonded ceramic substrate wherein the first metal layer is divided into a plurality of metal patterns.

11. In paragraph 10, The area occupied by the Cu block on one side of the first ceramic substrate is A multilayer metal bonded ceramic substrate formed in a range of 10% to 90% based on the lower surface area of ​​the metal pattern of the first metal layer connected to the Cu block.

12. Step of preparing a first ceramic substrate having an insertion hole formed therein; A step of laminating a second metal layer on the lower portion of the first ceramic substrate and inserting a Cu block into the insertion hole; A step of laminating a first metal layer on top of the first ceramic substrate and the Cu block; and A method for manufacturing a multilayer metal-bonded ceramic substrate, comprising the step of brazing the first metal layer, the first ceramic substrate, the Cu block, and the second metal layer.

13. In paragraph 12, A step of laminating a second ceramic substrate on the lower portion of the second metal layer, and laminating a third metal layer on the lower portion of the second ceramic substrate; and A method for manufacturing a multilayer metal-bonded ceramic substrate, further comprising the step of brazing the second metal layer, the second ceramic substrate, and the third metal layer.

14. In paragraph 12, After the step of brazing the first metal layer, the first ceramic substrate, the Cu block, and the second metal layer, A method for manufacturing a multilayer metal-bonded ceramic substrate, further comprising the step of etching the second metal layer to separate the intermediate metal layer bonded to the Cu block and the border metal layer arranged to surround the intermediate metal layer.

15. In paragraph 13, A method for manufacturing a multilayer metal-bonded ceramic substrate, further comprising the step of forming a circuit pattern on the first metal layer and the third metal layer.

16. In paragraph 15, In the step of forming the above circuit pattern, A method for manufacturing a multilayer metal-bonded ceramic substrate, wherein each of the first metal layer and the third metal layer is formed by etching an edge portion to leave a gap with the edge of an adjacent ceramic substrate.

17. In paragraph 12, The step of preparing the first ceramic substrate into which the above insertion hole is inserted is as follows: A method for manufacturing a multilayer metal-bonded ceramic substrate, comprising the step of forming a first bonding layer on the upper surface of the first ceramic substrate.

18. In paragraph 12, In the step of inserting the above Cu block, A method for manufacturing a multilayer metal-bonded ceramic substrate, wherein a second bonding layer is interposed between the first ceramic substrate and the second metal layer.

19. In paragraph 12, In the step of inserting the above Cu block, The above Cu block is a method for manufacturing a multilayer metal bonded ceramic substrate having a silver (Ag) plating film formed on the surface.

20. In paragraph 12, In the step of inserting the above Cu block, The above Cu block is inserted so that its side leaves a gap with the inner surface of the insertion hole, In the step of brazing the first metal layer, the first ceramic substrate, the Cu block, and the second metal layer, A method for manufacturing a multilayer metal-bonded ceramic substrate in which the above Cu block expands to come into contact with the inner surface of the above insertion hole.

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