Double-side active metal brazing substrate and method for manufacturing the same

Abstract

To provide a double-side active metal brazing substrate for overcoming disadvantages of an existing art, and to provide a manufacturing method of the double-side active metal brazing substrate.SOLUTION: A double-side active metal brazing substrate includes a ceramic substrate layer, first and second retaining walls, first and second active metal layers, and first and second conductive metal layers. The first active metal layer is disposed on a first surface of the ceramic substrate layer. The first active metal layer is surrounded by the first retaining wall and contacts the first retaining wall. The first conductive metal layer is disposed on the first active metal layer. The second active metal layer is disposed on a second surface of the ceramic substrate layer. The second active metal layer is surrounded by the second retaining wall and contacts the second retaining wall. The second conductive metal layer is disposed on the second active metal layer. The structural design of a thickness of the retaining wall being smaller than a thickness of the active metal layer can prevent overflow of solder.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a double-sided active metal bonded substrate and a method for manufacturing the same, and more particularly to a double-sided active metal bonded substrate having a highly accurate patterned circuit and a method for manufacturing the same. [Background technology]

[0002] Driven by the growing global awareness of energy saving and carbon reduction as well as various national policies, electric vehicles have become one of the major research and development projects of automobile manufacturers. In recent years, automobile manufacturers have launched a series of 800V high voltage vehicle models, which also drives demand for the properties of substrate materials.

[0003] Under operating conditions of high voltage, high frequency, and high operating temperature, ceramic substrates have higher reliability and heat dissipation capabilities than substrates made of other materials. Traditionally, the most widely used ceramic substrate was the direct-bonding-copper (DBC) ceramic substrate. However, traditional DBC ceramic substrates cannot meet the packaging requirements of high temperature, high power, high heat dissipation, and high reliability. Therefore, the current mainstream substrate material is gradually shifting from DBC ceramic substrates to active metal brazing (AMB) substrates.

[0004] In the manufacturing process of an AMB substrate, a layer of solder is first formed on the surface of a ceramic substrate. A copper layer is coated and then bonded to the substrate by a sintering process. A patterned circuit is then formed on the ceramic substrate by three or more etching processes. Alternatively, a patterned active metal solder may be printed on the surface of the ceramic substrate. A copper layer is coated and then bonded to the substrate by a sintering process. The copper layer is then etched to form the patterned circuit. The method of forming a patterned active metal solder not only saves solder in the inactive pattern areas and reduces costs, but also saves the process cost of subsequent secondary etching of the solder.

[0005] During the high-temperature sintering process, the patterned metal solder is prone to flow. If the solder overflows into areas without patterns, it will cause short circuits. Finally, the second etching process performed to remove the solder that has overflowed into the gaps between patterns does not save etching costs and reduces the overall pattern accuracy of the circuit, thereby affecting product quality.

[0006] Therefore, how to prevent solder overflow during the sintering process and overcome the above drawbacks by improving the structural design and manufacturing method has become one of the important problems to be solved in this technical field. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Chinese Patent Application Publication No. 108257876A [Patent Document 2] Chinese Patent Application Publication No. 113286442A [Patent Document 3] Chinese Patent No. 116544192B Specification Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE INVENTION It is an object of the present invention to provide a double-sided active metal bonding substrate and a method for manufacturing the same, which overcomes the drawbacks of existing techniques. [Means for solving the problem]

[0009] One aspect of the present invention provides a double-sided active metal bonding substrate, comprising: a ceramic substrate layer having a first surface and a second surface; a first active metal layer disposed on the first surface; a second active metal layer disposed on the second surface; a first support wall surrounding and in contact with the first active metal layer, the first support wall having a thickness smaller than that of the first active metal layer; a second support wall surrounding and in contact with the second active metal layer, the second support wall having a thickness smaller than that of the second active metal layer; a first conductive metal layer disposed on the first active metal layer; and a second conductive metal layer disposed on the second active metal layer.

[0010] According to some embodiments, the thickness ratio of the first retaining wall to the first active metal layer is between 0.10 and 0.95.

[0011] According to some embodiments, the first retaining wall comprises aluminum oxide, magnesium oxide, zirconium oxide, silicon oxide, aluminum nitride, or silicon nitride.

[0012] According to some embodiments, the first retaining wall has a thickness of 1 to 5 micrometers.

[0013] According to some embodiments, the width of the first retaining wall is between 0.1 mm and 30 mm.

[0014] According to some embodiments, the first active metal layer has a thickness of 10 to 50 micrometers.

[0015] Another aspect of the present invention provides a method for manufacturing a double-sided active metal bonded substrate, the method including: performing a patterning process to form a first support wall on a first surface of a ceramic substrate layer and a second support wall on a second surface of the ceramic substrate layer, wherein the first support wall defines a first patterned area and the second support wall defines a second patterned area; forming a first active metal layer in the first patterned area and a second active metal layer in the second patterned area; disposing a first conductive metal layer on the first active metal layer and a second conductive metal layer on the second active metal layer; and performing a brazing process to secure the first conductive metal layer to the ceramic substrate layer and the second active metal layer to the ceramic substrate layer. The thickness of the first support wall is less than the thickness of the first active metal layer, and the thickness of the second support wall is less than the thickness of the second active metal layer.

[0016] According to some embodiments, the sintering temperature in the brazing process is between 800 and 950°C.

[0017] According to some embodiments, the sintering pressure in the brazing process is 8×10 -5 Torr.

[0018] According to some embodiments, the double-sided active metal bonded substrate has a tensile strength greater than 100 N / cm. [Effects of the Invention]

[0019] One of the beneficial effects of the present invention is that the double-sided active metal bonding substrate and its manufacturing method provided by the present invention can prevent solder overflow at high temperatures by using the technical solution of the "retaining wall" and "the thickness of the retaining wall is smaller than the thickness of the active metal layer", thereby improving the bonding strength between the ceramic substrate layer and the conductive metal layer.

[0020] These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic side view of a double-sided active metal bonded substrate according to one embodiment of the present invention. [Figure 2] 1 is a schematic diagram illustrating the installation of a retaining wall on a ceramic substrate layer in accordance with the present invention. [Figure 3] 1 is a schematic diagram illustrating the process of depositing an active metal layer on a ceramic substrate layer in accordance with the present invention. [Figure 4] 1 is a schematic diagram illustrating a process for disposing a conductive metal layer on an active metal layer in accordance with the present invention. [Figure 5] FIG. 10 is a schematic side view of a double-sided active metal bonded substrate according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following are specific examples for illustrating the implementation of the "double-sided active metal bonded substrate and its manufacturing method" disclosed in the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed herein. The present invention may be implemented or applied in other different specific embodiments, and various details in this specification may be modified and changed based on different perspectives and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are merely schematic and, as mentioned in advance, are not drawn to actual scale. The following embodiments further describe the technical contents related to the present invention in detail, but the disclosed contents are not intended to limit the scope of the present invention. In addition, the term "or" used in this specification includes any one or combination of the associated multiple listed items, depending on the actual situation.

[0023] A technical feature of the present invention is that a retaining wall is placed on the ceramic substrate layer to define the patterned area and then active metal solder is formed in the patterned area to prevent solder from spilling over from the edge of the pattern into the non-patterned area during the sintering process. The retaining wall prevents the active metal solder from spilling over during the brazing process, ensuring that the double-sided active metal bonded substrate has a high-precision circuit pattern and eliminating the need for secondary etching of excess solder.

[0024] Another technical feature of the present invention is that the thickness of the retaining wall can be controlled. Experimental results have shown that in high-temperature environments, the material of the retaining wall can react with the active metal solder, adversely affecting the bonding strength between the active metal solder and the subsequent conductive metal layer. Therefore, by controlling the thickness of the retaining wall, the double-sided active metal bonding substrate can have higher tensile strength.

[0025] In the present disclosure, a double-sided active metal bonded substrate means that a conductive metal layer is provided on both sides (opposite sides) of the substrate. The conductive metal layers on both sides may have the same pattern or different patterns. For example, the conductive metal layer on one side can be used as a circuit layer, and the conductive metal layer on the other side can be used as a heat dissipation layer. Alternatively, the conductive metal layers on both sides can be used as circuit layers. However, the present invention is not limited thereto.

[0026] Referring to Figure 1, the double-sided active metal bonded substrate of the present invention includes a ceramic substrate layer 1, a first support wall 2, a second support wall 2', a first active metal layer 3, a second active metal layer 3', a first conductive metal layer 4, and a second conductive metal layer 4'.

[0027] The first retaining wall 2, the first active metal layer 3, and the first conductive metal layer 4 are disposed on a first surface 11 of the ceramic substrate layer 1, and the second retaining wall 2', the second active metal layer 3', and the second conductive metal layer 4' are disposed on a second surface 11' of the ceramic substrate layer 1. The structure of each layer of the double-sided active metal bonding substrate will be described below.

[0028] <Ceramic substrate layer> The ceramic substrate layer 1 is a substrate that can be used to support a double-sided printing structure and may include a silicon nitride (Si3N4) ceramic substrate, a silicon carbide (SiC) ceramic substrate, an aluminum nitride (AlN) ceramic substrate, or an aluminum oxide (Al2O3) ceramic substrate, preferably a silicon-containing ceramic substrate, more preferably a silicon nitride ceramic substrate. In addition, the thickness of the ceramic substrate layer 1 may be, but is not limited to, 0.25 mm to 1 mm.

[0029] <Retaining wall> The retaining wall is disposed on the ceramic substrate layer 1. The retaining wall can define a patterned area on the ceramic substrate layer 1. The patterned area can be designed or adjusted according to the pattern structure of the active metal layer and the conductive metal layer.

[0030] In the structure shown in FIG. 1 , a first retaining wall 2 is disposed on a first surface 11 and defines a patterned region. The extent of the patterned region can be designed or adjusted depending on the pattern structures of a first active metal layer 3 and a first conductive metal layer 4. Similar to the first retaining wall 2, a second retaining wall 2′ is disposed on a second surface 11′ and defines another patterned region. The extent of this patterned region can be designed or adjusted depending on the pattern structures of a second active metal layer 3′ and a second conductive layer 4′.

[0031] The conductive metal layers on both sides of the ceramic substrate layer may have the same pattern or different patterns, so that the patterned area defined by the first retaining wall 2 may be the same as or different from the patterned area defined by the second retaining wall 2'.

[0032] The retaining wall can prevent the active metal layer from spilling out of the patterned area in a high temperature environment (such as a brazing process), so as to produce a double-sided active metal bonded substrate with highly accurate patterned circuits.

[0033] To prevent the active metal layer from spilling over the patterned area, the retaining wall is made of a highly heat-resistant material that has a low affinity with the material of the active metal layer, and even when the molten active metal layer material contacts the retaining wall, the active metal layer material does not accumulate beyond the patterned area defined by the retaining wall due to its large agglomeration.

[0034] Specifically, the material of the retaining wall may be aluminum oxide (Al2O3), magnesium oxide (MgO), zirconium oxide (ZrO2), silicon oxide (SiO2), aluminum nitride (AlN), or silicon nitride (Si3N4). For example, the retaining wall may be composed of particles of the above-mentioned high-temperature-resistant material. A retaining wall composed of particles may reduce the affinity between the material of the retaining wall and the material of the active metal layer. For example, the average particle size (grain size) of the particles is less than 12 micrometers. In an exemplary embodiment, the average particle size of the particles is 3 to 12 micrometers, for example, a positive integer between 3 and 12 micrometers.

[0035] Furthermore, the width of the retaining wall can be further controlled to achieve a good barrier effect. A wider retaining wall makes it more difficult for the active metal layer material to cross the retaining wall beyond the patterned area. In an exemplary embodiment, the width of the retaining wall is 0.1 mm to 30 mm. For example, the width of the retaining wall may be a positive integer between 0.1 mm and 30 mm.

[0036] Regarding the thickness of the retaining wall, experimental results show that in a high temperature environment, the material of the retaining wall may react with the material of the active metal layer at the contact surface or may diffuse to the top surface of the active metal layer.

[0037] Specifically, the original purpose of the active metal layer is to combine with the conductive metal layer. However, if the material of the active metal layer reacts with the material of the retaining wall or diffuses into the interface between the active metal layer and the conductive metal layer, the bonding strength between the material of the active metal layer and the material of the conductive metal layer may decrease. Therefore, another technical feature of the present invention is to further control the thickness of the retaining wall to be smaller than the thickness of the active metal layer to prevent the active metal layer from overflowing the patterned area without decreasing the bonding strength of the conductive metal layer.

[0038] For ease of defining the thickness of each layer, in this disclosure, the thickness of the first retaining wall 2 and the thickness of the first active metal layer 3 refer to the direction perpendicular to the first surface 11. The thickness of the second retaining wall 2' and the thickness of the second active metal layer 3' refer to the direction perpendicular to the second surface 11'.

[0039] Furthermore, the present invention improves the pattern circuit accuracy of the double-sided active metal bonded substrate by controlling the thickness ratio of the retaining wall to the active metal layer without adversely affecting the bonding strength between the materials of the active metal layer and the conductive metal layer. Specifically, the thickness ratio of the first retaining wall 2 to the first active metal layer 3 is 0.10 to 0.95. For example, the thickness ratio of the first retaining wall 2 to the first active metal layer 3 may be 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, or 0.90. The thickness ratio of the second retaining wall 2' to the second active metal layer 3' is 0.10 to 0.95. For example, the thickness ratio of the second retaining wall 2' to the second active metal layer 3' may be 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85 or 0.90.

[0040] In an exemplary embodiment, the first retaining wall 2 has a thickness of 1 to 5 micrometers, and the second retaining wall 2' has a thickness of 1 to 5 micrometers.

[0041] To achieve the above thickness design of the retaining wall, the retaining wall can be disposed on the ceramic substrate layer 1 by screen printing. However, the method of disposing the retaining wall is not limited to this. As long as the thickness of the retaining wall can be made thinner than the thickness of the active metal layer, the method can be applied to the present invention.

[0042] <Active metal layer> The active metal layer is disposed in the patterned area defined by the retaining wall, and the active metal layer is disposed between the ceramic substrate layer 1 and the conductive metal layer, fixing the conductive metal layer onto the ceramic substrate layer 1.

[0043] 1, the first active metal layer 3 is disposed within the patterned area defined by the first retaining wall 2, i.e., the first retaining wall 2 surrounds the first active metal layer 3. To more precisely control the shape of the circuit layer, the first retaining wall 2 can be in contact with the side of the first active metal layer 3 to prevent the active metal solder from overflowing from the patterned area in a high-temperature environment.

[0044] Similar to the first active metal layer 3, the second active metal layer 3' is disposed within the patterned area defined by the second retaining wall 2', i.e., the second retaining wall 2' surrounds the second active metal layer 3'. Furthermore, the second retaining wall 2' can be in contact with the side surface of the second active metal layer 3' to prevent the active metal solder from overflowing the patterned area in a high temperature environment.

[0045] The active metal layer is formed from an active metal solder paste, which includes an active metal solder and an organic dispersant, and the active metal solder is dispersed in the organic dispersant. Under high temperature conditions, the active metal solder can form an alloy with the material of the ceramic substrate layer and also with the material of the conductive metal layer to achieve a bonding effect.

[0046] The active metal solder includes metallic silver (Ag), metallic copper (Cu), and an active metal. Specifically, the active metal may be selected from the group consisting of metallic titanium (Ti), metallic zirconium (Zr), metallic tantalum (Ta), metallic niobium (Nb), metallic vanadium (V), and metallic hafnium (Hf). In a preferred embodiment, the active metal solder includes metallic silver (Ag), metallic copper (Cu), and metallic titanium (Ti). In a high-temperature environment (brazing process), some metals can diffuse into the ceramic substrate to form metal silicides or metal nitrides, and some metals can also diffuse into the conductive metal layer to form an alloy, improving the mutual joining effect.

[0047] As described above, by coating an active metal layer on a patterned area surrounded by a retaining wall and controlling the thickness of the active metal layer to be greater than the thickness of the retaining wall, the double-sided active metal bonding substrate of the present invention can have a higher tensile strength.

[0048] As the thickness of the active metal layer increases, the bonding strength between the ceramic substrate layer and the conductive metal layer also increases. However, if the active metal layer is too thick, the material cost of the active metal layer becomes too high, which is not conducive to mass production. Therefore, the thickness of the active metal layer 2 is 6 micrometers or more. If the thickness of the active metal layer is not smaller than the retaining wall and does not cause process cost issues, the thickness of the active metal layer can be 10 to 50 micrometers. For example, the thickness of the active metal layer 2 can be a positive integer between 10 and 50 micrometers.

[0049] <Conductive metal layer> The conductive metal layer is disposed on the active metal layer. Because the adhesive strength between the conductive metal layer and the ceramic substrate layer 1 is weak, the conductive metal layer must be disposed on the ceramic substrate layer via the active metal layer.

[0050] Through different structural designs, the conductive metal layer can be used as a circuit layer or a heat dissipation layer of the double-sided active metal bonding substrate. When used as a circuit layer, the pattern accuracy of the conductive metal layer has a significant impact on the quality of the double-sided active metal bonding substrate.

[0051] 1, the first conductive metal layer 4 is fixed onto the first surface 11 of the ceramic substrate layer 1 via the first active metal layer 3. The pattern structure of the first conductive metal layer 4 corresponds to the pattern structure of the first active metal layer 3. Similar to the first conductive metal layer 4, the second conductive metal layer 4' is disposed on the second surface 11' of the ceramic substrate layer 1 via the second active metal layer 3'. The pattern structure of the second conductive metal layer 4' corresponds to the pattern structure of the first conductive metal layer 4'.

[0052] Specifically, the conductive metal layer may be a metallic copper foil, a metallic aluminum foil, or a copper-aluminum alloy foil. In a preferred embodiment, the conductive metal layer is a metallic copper foil.

[0053] Since the bonding strength between the ceramic substrate layer and the conductive metal layer of the present invention is better, a thicker conductive metal layer can be soldered, and the thickness of the conductive metal layer can be 0.2 mm to 1.5 mm, for example, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, or 1.4 mm.

[0054] <Method of manufacturing a double-sided active metal bonded substrate> The method for manufacturing a double-sided active metal bonded substrate of the present invention includes sequentially forming a retaining wall (pattern forming process), an active metal layer (coating process, drying process), and a conductive metal layer on a ceramic substrate layer, and then performing a brazing process to complete the double-sided active metal bonded substrate.

[0055] As described above, the retaining wall, active metal layer, and conductive metal layer are formed on both sides of the ceramic substrate layer. In actual operation, the retaining wall can be formed on the first and second surfaces of the ceramic substrate layer as needed, and then the active metal layer and conductive metal layer are sequentially formed on the first and second surfaces. In some embodiments, the retaining wall, active metal layer, and conductive metal layer may be sequentially formed on the first surface of the ceramic substrate layer, and then the retaining wall, active metal layer, and conductive metal layer are sequentially formed on the second surface of the ceramic substrate layer.

[0056] In step S1, a patterning process is carried out to form a retaining wall on the ceramic substrate layer, and the structural design of the retaining wall defines a patterned area, as shown in FIG.

[0057] That is, a first retaining wall is formed on a first surface of the ceramic substrate layer, the first retaining wall defining a first patterned area. A second retaining wall is formed on a second surface of the ceramic substrate layer, the second retaining wall defining a second patterned area. For convenience of explanation, the following description of the method for manufacturing the double-sided active metal bonded substrate will be given in a general sense, but the present invention is not limited thereto.

[0058] In the patterning process, the retaining walls may be formed by, but are not limited to, screen printing.

[0059] In step S2, a preparation process is carried out to prepare an active metal solder paste, which is used to form the active metal layer, and the active metal solder paste contains the active metal solder and an organic dispersion medium.

[0060] The active metal solder includes metallic silver, metallic copper, and the active metals described above. In some embodiments, the active metal solder is a combination of metallic silver powder, metallic copper powder, and metallic titanium powder. In some other embodiments, the active metal solder may be a combination of at least one of metallic silver powder, metallic copper powder, and silver-copper alloy powder with the active metal powder.

[0061] If the total weight of the active metal solder is 100% by weight, the content of metallic silver in the active metal solder is 10 to 60% by weight, the content of metallic copper is 30 to 80% by weight, and the content of active metal is 1 to 10% by weight.

[0062] The organic dispersion medium helps disperse the active metal solder and aids in forming the active metal solder paste to form the active metal layer. Specifically, the organic dispersion medium includes a paste-forming agent, an organic solvent, and a thixotropic agent. When the total weight of the organic dispersion medium is 100 wt%, the content of the paste-forming paste is 20 to 30 wt%, the content of the organic solvent is 50 to 70 wt%, and the content of the thixotropic agent is 1 to 5 wt%. However, the present invention is not limited to these contents as long as the active solder powder and organic components can be blended into an active solder having a viscosity suitable for coating on a ceramic substrate layer, facilitating the formation of an active metal layer.

[0063] In step S3, a coating process is performed to coat the patterned area with an active metal solder paste, which can be applied to the patterned area by screen printing.

[0064] In step S4, a drying process is performed to form an active metal layer from the active metal solder paste. In the drying process, as shown in Figure 3, the active metal solder paste is dried at a temperature of 90 to 110°C for 5 to 15 minutes to form an active metal layer by volatilizing most of the organic solvent in the active metal solder paste.

[0065] In step S5, a conductive metal layer is disposed on the active metal layer, as shown in FIG.

[0066] In step S6, a brazing process is performed to connect the conductive metal layer to the active metal layer and secure it to the ceramic substrate layer.

[0067] In the brazing process, 8 × 10 -5 The first and second heat treatment processes can be carried out sequentially at a vacuum of Torr or less. The temperature conditions for the first heat treatment process are 800 to 890°C, and the temperature conditions for the second heat treatment process are 900 to 1100°C (i.e., the brazing temperature range). The temperature for the second heat treatment process is higher than that of the first heat treatment process, and is maintained at the maximum temperature for 30 minutes.

[0068] In a preferred embodiment, the temperature ramp (heating) rate in the heat treatment process may be, for example, 5°C / min to 30°C / min. The cooling rate after the brazing process may be, for example, 2°C / min to 30°C / min.

[0069] After the conductive metal layer is applied, an etching process can be selectively performed to remove the conductive metal layer outside the patterned areas, achieve the patterning, and form the final product as shown in FIG.

[0070] In some embodiments, during the etching process, the retaining walls may also be removed along with the conductive metal layer outside the patterned areas, resulting in a double-sided active metal-bonded substrate as shown in Figure 5. This step is optional, and the retaining walls do not have to be removed. [Example]

[0071] To verify that the double-sided active metal bonded substrate of the present invention has a highly accurate pattern circuit, double-sided active metal bonded substrates of Examples 1 to 3 and single-sided active metal bonded substrates of Comparative Examples 1 to 3 were fabricated according to the above steps S1 to S6.

[0072] <Examples 1 to 3> In the double-sided active metal bonded substrates of Examples 1 to 3, the ceramic substrate layer is a silicon nitride ceramic substrate. The material of the first support wall and the second support wall is aluminum oxide. The material of the first active metal layer and the second active metal layer includes metallic silver, metallic copper, and metallic titanium. The total weight of the active metal solder is 100 wt %, the content of metallic silver is 70 wt %, the content of metallic copper is 25 wt %, and the content of metallic titanium is 5 wt %. The first conductive metal layer and the second conductive metal layer are metallic copper foil.

[0073] The differences between Examples 1 to 3 include different thicknesses of the active metal layer and different thickness ratios of the retaining wall to the active metal layer.

[0074] In the brazing process, the vacuum level is 8 x 10 -5 Torr or less, the temperature condition for the first stage heat treatment process is 855°C, and the temperature condition for the second stage heat treatment process is 915°C, and the maximum temperature is maintained for 30 minutes.

[0075] After preparing the active metal bonding substrates, the thickness of the retaining wall, the thickness of the active metal layer, the printing position, and the presence or absence of solder diffusion after brazing in Examples 1 to 3 were measured, and the results are shown in Table 1. In addition, the tensile strength of the active metal bonding substrates at a temperature of 25°C was measured in accordance with JIS-C-6481. The results are shown in Table 1.

[0076] <Comparative Examples 1 to 3> The single-sided active metal bonded substrates of Comparative Examples 1 to 3 were fabricated using the same manufacturing method as the double-sided active metal bonded substrate of Example 1. Comparative Examples 1 to 3 have a layer on only one side of the ceramic substrate layer. In Comparative Examples 1 and 2, the thickness of the support wall was greater than the thickness of the active metal layer, and in Comparative Example 3, no support wall was provided.

[0077] After preparing the active metal bonding substrates, the results of the thickness of the retaining wall, the thickness of the active metal layer, the printing position, and whether or not the solder diffused after brazing in Comparative Examples 1 to 3 are shown in Table 1. In addition, the tensile strength of the active metal bonding substrates at a temperature of 25°C was measured in accordance with JIS-C-6481. The results are shown in Table 1.

[0078] [Table 1]

[0079] The results in Table 1 show that the retaining wall prevents solder diffusion and maintains the fineness of the circuit pattern of the active metal bonding substrate. Furthermore, by controlling the thickness of the retaining wall to be smaller than the thickness of the active metal layer, the tensile strength of the active metal bonding substrate can be increased.

[0080] Therefore, the double-sided active metal bonded substrate of the present invention can prevent the active metal layer from overflowing from the patterned area without reducing the bonding strength of the conductive metal layer (tensile strength exceeding 100 N / cm). The double-sided printed structure of the present invention has higher functionality than a single-sided printed structure without affecting the overall structural strength, and maintains a tensile strength exceeding 100 N / cm.

[0081] [Beneficial Effects of the Embodiments] One of the beneficial effects of the present invention is that the double-sided active metal bonding substrate and its manufacturing method provided by the present invention can prevent solder overflow at high temperatures by using the technical solution of the "retaining wall" and "the thickness of the retaining wall is smaller than the thickness of the active metal layer", thereby improving the bonding strength between the ceramic substrate layer and the conductive metal layer.

[0082] Those skilled in the art will readily appreciate that numerous modifications and variations of the apparatus and method may be made while retaining the teachings of the present invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims. [Explanation of symbols]

[0083] 1. Ceramic substrate layer 2. First retaining wall 2' Second retaining wall 3. First active metal layer 3' Second active metal layer 4. First conductive metal layer 4' Second conductive metal layer 11 First surface of ceramic substrate layer 1 11' second surface of ceramic substrate layer 1

Claims

1. A double-sided active metal bonded substrate, a ceramic substrate layer having a first surface and a second surface; a first active metal layer disposed on the first surface; a second active metal layer disposed on the second surface; a first retaining wall surrounding and in contact with the first active metal layer, the first retaining wall having a thickness less than a thickness of the first active metal layer; a second retaining wall surrounding and in contact with the second active metal layer, the second retaining wall having a thickness less than the thickness of the second active metal layer; a first conductive metal layer disposed on the first active metal layer; a second conductive metal layer disposed on the second active metal layer; A double-sided active metal bonded substrate comprising:

2. 2. The double-sided active metal bonded substrate according to claim 1, wherein the thickness ratio of the first support wall to the first active metal layer is 0.10 to 0.

95.

3. 2. The double-sided active metal bonding substrate according to claim 1, wherein the first support wall comprises aluminum oxide, magnesium oxide, zirconium oxide, silicon oxide, aluminum nitride, or silicon nitride.

4. 2. The double-sided active metal bonding substrate according to claim 1, wherein the first support wall has a thickness of 1 to 5 micrometers.

5. 2. The double-sided active metal bonded substrate according to claim 1, wherein the width of the first holding wall is 0.1 mm to 30 mm.

6. 2. The double-sided active metal bonded substrate according to claim 1, wherein the thickness of the first active metal layer is 10 to 50 micrometers.

7. A method for manufacturing a double-sided active metal bonded substrate, comprising: performing a patterning process to form a first retaining wall on a first surface of a ceramic substrate layer and a second retaining wall on a second surface of the ceramic substrate layer, the first retaining wall defining a first patterned area and the second retaining wall defining a second patterned area; forming a first active metal layer in the first patterned area and a second active metal layer in the second patterned area; disposing a first conductive metal layer on the first active metal layer and a second conductive metal layer on the second active metal layer; performing a brazing process to secure the first conductive metal layer to the ceramic substrate layer and the second active metal layer to the ceramic substrate layer; wherein the first retaining wall has a thickness less than the thickness of the first active metal layer and the second retaining wall has a thickness less than the thickness of the second active metal layer.

8. The method according to claim 7, wherein the sintering temperature in the brazing process is 800-950°C.

9. The sintering pressure in the brazing process is 8×10 －５ 8. The method of claim 7, wherein the pressure is less than Torr.

10. The method of claim 7 , wherein the double-sided active metal bonded substrate has a tensile strength greater than 100 N / cm.

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