Copper-ceramic circuit board and method for manufacturing same

Abstract

The present invention provides an inexpensive copper-ceramic circuit board and a method for manufacturing the same, which can support higher dimensional accuracy (lower dimensional variation) than conventional copper-ceramic circuit boards. A circuit pattern copper plate and a heat sink pattern copper plate having an arithmetic average roughness (Ra) of 0.1 [mu] m or less are prepared, and the other surfaces of the circuit pattern copper plate and the heat sink pattern copper plate are bonded to one surface and the other surface of a ceramic substrate, respectively, via a solder. An etching resist having a circuit pattern shape and a heat sink pattern shape is formed on one surface of each of a copper plate for a circuit pattern and a copper plate for a heat sink pattern, and a part of each of the copper plate for the circuit pattern and the copper plate for the heat sink pattern is etched. Thus, a copper-ceramic circuit board in which a circuit pattern copper plate (114) having a circuit pattern shape and a heat sink pattern copper plate (116) having a heat sink pattern shape are joined to a ceramic substrate (12) via a solder (118) is manufactured.

Description

Technical Field

[0001] The present invention relates to a copper-ceramic circuit substrate and a method for manufacturing the same, and in particular to a copper-ceramic circuit substrate in which a circuit pattern copper plate is bonded to a ceramic substrate by solder. Background Art

[0002] In the past, power modules were used to control high power in electric vehicles, trams, machine tools, etc. As an insulating substrate for such power modules, a metal-ceramic circuit substrate is used, which is obtained by bonding a metal circuit board to one surface of a ceramic substrate, and the metal circuit board is composed of Cu, Al, etc. having a predetermined circuit pattern. In such a metal-ceramic circuit substrate, a power semiconductor such as a Si semiconductor is mounted on the metal circuit board, and a metal heat sink is usually bonded to the other surface of the ceramic substrate.

[0003] In recent years, wide-bandgap semiconductors such as SiC semiconductors and GaN semiconductors have begun to be used as power semiconductors to replace existing Si semiconductors. Such wide-bandgap semiconductors have low on-resistance, so even a chip that is smaller than the existing Si semiconductor chip can control the same power as the Si semiconductor. Therefore, it is required to make the space (line and space (L / S)) of the wiring pattern of the metal-ceramic circuit substrate used in the power module more miniaturized than before.

[0004] In addition, as a method for manufacturing a metal-ceramic circuit substrate, the following method has been proposed (for example, refer to Patent Document 1): after a metal plate is joined to at least one surface of a ceramic substrate via a solder, the metal plate is etched into a predetermined shape, and then, the solder exposed by etching is removed using a solution containing a chelating agent and hydrogen peroxide or a solution containing a chelating agent, hydrogen peroxide and an alkali, thereby manufacturing a ceramic circuit substrate.

[0005] In addition, a method has been proposed (see, for example, Patent Document 2) in which a metal layer is formed on at least one surface of an insulator to obtain a metal-insulator composite member, and then at least a portion of the metal layer is milled to form a pattern to produce a circuit board.

[0006] In addition, the following method has been proposed (for example, refer to Patent Document 3): a brazing material containing an active metal is coated on substantially the entire surface of one surface of a ceramic substrate, a metal plate is arranged on the brazing material containing the active metal, the metal plate is bonded to the ceramic substrate, and then a resist is formed on substantially the entire surface of the metal plate, a prescribed portion of the resist is removed by laser irradiation to form a resist for forming a circuit pattern, unnecessary portions of the metal plate are etched, and then the resist for forming the circuit pattern is removed to form a plurality of circuit patterns, and unnecessary portions of the brazing material containing the active metal are removed, and then a scribe line is formed between adjacent circuit patterns on one surface of the ceramic substrate, and the ceramic substrate is divided along the scribe line to manufacture a plurality of metal-ceramic bonded circuit substrates. Prior art literature Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2003-60111 (Paragraph No. 0006) Patent Document 2: Japanese Patent Application Laid-Open No. 2004-296619 (Paragraph No. 0008) Patent Document 3: Japanese Patent Application Publication No. 2019-67854 (Paragraph No. 0012) Summary of the invention Technical problem to be solved by the invention

[0008] However, the methods of Patent Documents 1 and 2 cannot support higher dimensional accuracy (lower dimensional deviation) to cope with the miniaturization of the space (line and space (L / S)) of the wiring pattern required in the metal-ceramic circuit substrate for power modules in recent years. In addition, the methods of Patent Documents 2 and 3 are not sufficient in terms of the large number of manufacturing processes, productivity and cost.

[0009] Therefore, in view of the above-mentioned conventional problems, an object of the present invention is to provide an inexpensive copper-ceramic circuit substrate and a method for manufacturing the same, which can support higher dimensional accuracy (lower dimensional deviation) than the prior art. Technical solutions to technical problems

[0010] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that: a copper plate for circuit pattern having an arithmetic mean roughness Ra of less than 0.1 μm on one surface is prepared, and the other surface of the copper plate for circuit pattern is joined to one surface of a ceramic substrate via solder, and then an etching resist in the shape of a circuit pattern is formed on one surface of the copper plate for circuit pattern, and a portion of the copper plate for circuit pattern is etched to form a circuit pattern copper plate in the shape of a circuit pattern, thereby manufacturing an inexpensive copper-ceramic circuit substrate that can support higher dimensional accuracy (lower dimensional deviation) than the existing ones, thereby completing the present invention.

[0011] That is, the manufacturing method of the copper-ceramic circuit substrate involved in the present invention is characterized in that a copper plate for circuit pattern having an arithmetic mean roughness Ra of less than 0.1 μm on one surface is prepared, and after joining the other surface of the copper plate for circuit pattern and one surface of a ceramic substrate via solder, an etching resist in the shape of a circuit pattern is formed on one surface of the copper plate for circuit pattern, and a part of the copper plate for circuit pattern is etched to form a circuit pattern copper plate in the shape of a circuit pattern.

[0012] In the manufacturing method of the copper-ceramic circuit substrate, it is preferred that the thickness of the copper plate for the circuit pattern is 0.1 to 1.0 mm, and it is preferred that the copper plate for the circuit pattern is obtained by reducing the surface roughness of one surface of the copper plate by skin-rolling or chemical polishing. In addition, it is preferred that the arithmetic mean roughness Ra of one surface of the copper plate for the circuit pattern is less than 0.07 μm, and it is preferred that an etching resist in the shape of a circuit pattern is formed by printing an etching resist ink on one surface of the copper plate for the circuit pattern and then curing it. In addition, it is preferred that the ceramic substrate is composed of aluminum nitride, silicon nitride or aluminum oxide, and it is preferred that the brazing material contains silver and copper, and contains Ti or Zr as an active metal. In addition, it is preferred that when the other surface of the copper plate for the circuit pattern is joined to one surface of the ceramic substrate via the brazing material, the copper plate for the heat sink pattern is joined to the other surface of the ceramic substrate via the brazing material, and an etching resist in the shape of a heat sink pattern is formed on the surface of the copper plate for the heat sink pattern, and a portion of the copper plate for the heat sink pattern is etched to form a heat sink pattern copper plate in the shape of a heat sink pattern.

[0013] The copper-ceramic circuit board according to the present invention is characterized in that the other surface of a circuit pattern copper plate having an arithmetic mean roughness Ra of 0.1 μm or less on one surface is joined to one surface of a ceramic substrate via a brazing material.

[0014] In the copper-ceramic circuit substrate, the other surface of the heat sink pattern copper plate whose arithmetic mean roughness Ra is preferably 0.1 μm or less is bonded to the other surface of the ceramic substrate via a brazing material. In addition, the thickness of the circuit pattern copper plate is preferably 0.1 to 1.0 mm, and the arithmetic mean roughness Ra of one surface of the circuit pattern copper plate is preferably 0.07 μm or less. In addition, the ceramic substrate is preferably composed of aluminum nitride, silicon nitride or aluminum oxide, and the brazing material preferably contains silver and copper, and contains Ti or Zr as an active metal. Effects of the Invention

[0015] According to the present invention, it is possible to provide an inexpensive copper-ceramic circuit substrate and a method for manufacturing the same which can support higher dimensional accuracy (lower dimensional deviation) than conventional ones. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1It is a plan view showing a state where a copper plate is bonded to a ceramic substrate via a brazing material (copper-ceramic bonded substrate) in a manufacturing process of an embodiment of a copper-ceramic circuit substrate according to the present invention. Figure 2 yes Figure 1 A cross-sectional view of the copper-ceramic bonding substrate taken along line II-II. Figure 3 This is a plan view showing a state where an etching resist in a circuit pattern shape is formed on a circuit pattern copper plate of a copper-ceramic joint substrate in a manufacturing process of an embodiment of a copper-ceramic circuit substrate according to the present invention. Figure 4 This is a plan view showing a state where an etching resist in a heat sink pattern shape is formed on a heat sink pattern copper plate of a copper-ceramic bonded substrate in a manufacturing process of an embodiment of a copper-ceramic circuit substrate according to the present invention. Figure 5 It is a top view of the copper-ceramic circuit board manufactured by the embodiment of the copper-ceramic circuit board concerning this invention. Figure 6 yes Figure 5 VI-VI cross-sectional view of the copper-ceramic bonding substrate. DETAILED DESCRIPTION

[0017] Hereinafter, the copper-ceramic circuit substrate and the manufacturing method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

[0018] In the embodiment of the method for manufacturing the copper-ceramic circuit substrate of the present invention, Figure 1 and Figure 2 As shown, a copper plate 14 for a circuit pattern and a copper plate 16 for a heat sink pattern, each having an arithmetic mean roughness Ra of 0.1 μm or less, are prepared respectively, and the other surfaces of each of the copper plates 14 for a circuit pattern and 16 for a heat sink pattern are bonded to the respective surfaces of a ceramic substrate 12 via a solder 18, thereby manufacturing a copper-ceramic bonded substrate 10.

[0019] Then, if Figure 3 As shown, an etching resist 20 in the shape of a circuit pattern is formed on one surface of the circuit pattern copper plate 14, and as shown in FIG. Figure 4 As shown, an etching resist 22 in the shape of a heat sink pattern is formed on one surface of the heat sink pattern copper plate 16 .

[0020] Then, if Figure 5 and Figure 6As shown, a portion of the circuit pattern copper plate 14 and the heat sink pattern copper plate 16 are etched to form a circuit pattern copper plate 114 in the shape of a circuit pattern and a heat sink pattern copper plate 116 in the shape of a heat sink pattern, thereby making a copper-ceramic circuit substrate 100 in which the circuit pattern copper plate 114 and the heat sink pattern copper plate 116 are joined to the ceramic substrate 12 via solder 118 as an embodiment of the copper-ceramic circuit substrate involved in the present invention.

[0021] The ceramic substrate 12 is made of a material that maintains insulation between circuit patterns on the substrate or between the front and back surfaces of the substrate. Non-oxide ceramic substrates such as ceramic substrates with aluminum nitride as a main component and ceramic substrates with silicon nitride as a main component, and oxide ceramic substrates with aluminum oxide as a main component can be used as the ceramic substrate 12. The size of the ceramic substrate 12 is preferably 5 to 200 mm in length, 5 to 200 mm in width, and 0.2 to 3.0 mm in thickness, and more preferably 10 to 100 mm in length, 10 to 100 mm in width, and 0.25 to 2.0 mm in thickness.

[0022] The copper plate 14 for circuit pattern and the copper plate 16 for heat sink pattern are preferably rolled copper plates composed of oxygen-free copper plates (C1020) and the like, and the arithmetic mean roughness Ra of one surface thereof is preferably 0.1 μm or less, and more preferably 0.07 μm or less. In addition, the arithmetic mean roughness Ra of the other surface of the copper plate 14 for circuit pattern and the copper plate 16 for heat sink pattern can be 0.1 μm or less, or 0.07 μm or less. In addition, the thickness of the copper plate 14 for circuit pattern and the copper plate 16 for heat sink pattern used in the copper-ceramic bonding substrate 10 for power module is about 0.1 to 1.0 mm, but the arithmetic mean roughness Ra of the surface (plate surface) of such rolled copper plate exceeds 0.1 μm, and is usually about 0.15 to 0.3 μm. That is, the arithmetic mean roughness Ra of the surface (plate surface) of such a rolled copper plate cannot be set to below 0.1 μm in a normal rolling process. Therefore, when such a rolled copper plate is used as a circuit pattern copper plate 14 and a heat sink pattern copper plate 16 each having an arithmetic mean roughness Ra of 0.1 μm or less on one surface thereof, it is necessary to reduce the surface roughness of one surface of each of the circuit pattern copper plate 14 and the heat sink pattern copper plate 16 to a smooth surface through tempering rolling such as skin pass rolling or chemical polishing. Thus, using a circuit pattern copper plate 14 and a heat sink pattern copper plate 16 each having an arithmetic mean roughness Ra of less than 0.1 μm on one surface, the other surfaces of the circuit pattern copper plate 14 and the heat sink pattern copper plate 16 are joined to respective surfaces of the ceramic substrate 12 via a solder 18, an etching resist 20 in the shape of a circuit pattern is formed on one surface of the circuit pattern copper plate 14, and an etching resist 22 in the shape of a heat sink pattern is formed on one surface of the heat sink pattern copper plate 16, and then a portion of the circuit pattern copper plate 14 and the heat sink pattern copper plate 16 are etched to form a circuit pattern copper plate 114 in the shape of a circuit pattern and a heat sink pattern copper plate 116 in the shape of a heat sink pattern. If this method is adopted, a circuit pattern copper plate 114 and a heat sink pattern copper plate 116 with very high dimensional accuracy (extremely low dimensional deviation) can be obtained. In addition, from the viewpoint of manufacturing cost, the arithmetic mean roughness Ra of one surface of each of the circuit pattern copper plate 14 and the heat sink pattern copper plate 16 is preferably 0.01 μm or more.

[0023] The brazing material 18 as a bonding material for bonding the ceramic substrate 12 to the copper plate 14 for the circuit pattern and the copper plate 16 for the heat sink pattern is preferably a so-called Ag-Cu-Ti type or Ag-Cu-Zr type brazing material containing active metals, which contains Ag and Cu as main components and contains Ti or Zr as active metals. When using the Ag-Cu-Ti type or Ag-Cu-Zr type brazing material containing active metals, the content of Ag in the brazing material (the ratio of the mass of Ag to the total mass of the metal components contained in the brazing material) is not particularly limited, but from the viewpoint of improving reliability such as bonding strength, it is preferably 30 to 95% by mass, more preferably 50 to 90% by mass, and most preferably 65 to 90% by mass. In addition, the content of the active metal component in the brazing material (the ratio of the mass of the active metal component to the total mass of the metal components contained in the brazing material) is preferably 1.0 to 7.0% by mass, and more preferably 1.5 to 6.5% by mass. By using such a solder, the bonding strength between the ceramic substrate 12 and the copper plate 14 for the circuit pattern and the copper plate 16 for the heat sink pattern can be improved. In addition, when using an Ag-Cu type solder containing an active metal, the content of the (remaining) metal component other than Ag and the active metal component is the content of Cu. In addition, when a paste or foil solder is used as the solder 18, it is preferred to use a paste solder from the viewpoint of manufacturing cost and operability. When a paste solder is used, for example, after being applied to the ceramic substrate 12 by screen printing or the like, it is dried at a temperature below 200°C in the air or in an inert gas atmosphere, so that the solder 18 can be formed on the ceramic substrate 12. The thickness of the solder 18 is not particularly limited, but from the viewpoint of ensuring the heat shock resistance and bonding strength of the copper-ceramic bonding substrate 10, it is preferably 3 to 50 μm, and more preferably 5 to 20 μm.

[0024] The etching resist 20 in the shape of the circuit pattern and the etching resist 22 in the shape of the heat sink pattern are preferably formed by printing and curing by a known method such as screen printing, lamination, photomask method, etc., but from the viewpoint of productivity, it is preferably formed by printing etching resist ink by screen printing and curing. As the etching resist ink, it is preferable to use an ultraviolet curing alkali stripping type etching resist ink.

[0025] A portion (unnecessary portion) of the circuit pattern copper plate 14 and the heat sink pattern copper plate 16 (the portion of the circuit pattern copper plate 114 and the heat sink pattern copper plate 116 where the etching resist is not formed) is etched, wherein a known etching solution, such as an etching solution containing cupric chloride, ferric chloride or hydrogen peroxide water, is removed, and then hydrofluoric acid, a chelating agent, etc. are used to remove unnecessary solder (remaining on the surface of the ceramic substrate 12 around the circuit pattern copper plate 114 and the heat sink pattern copper plate 116), thereby forming the desired circuit pattern copper plate 114 and the heat sink pattern copper plate 116, thereby manufacturing the copper-ceramic circuit substrate 100. In addition, the surfaces of the circuit pattern copper plate 114 and the heat sink pattern copper plate 116 of the copper-ceramic circuit substrate 100 manufactured in this way can be electroplated by chemical Ni-P plating, Ni electroplating, etc.

[0026] In addition, it can be considered that, for example, in the case of forming an etching resist 20 in the shape of a circuit pattern by screen printing, if the surface of the circuit pattern copper plate 14 has large unevenness, the difference in the diffusion of the etching resist ink becomes larger depending on the location, and the dimensional deviation between the etching resist 20 and the circuit pattern copper plate 114 increases.

[0027] In an embodiment of the copper-ceramic circuit substrate involved in the present invention manufactured by the embodiment of the copper-ceramic circuit substrate manufacturing method of the above-mentioned present invention, the other surface of the circuit pattern copper plate having an arithmetic mean roughness Ra of less than 0.1 μm on one surface is joined to one surface of the ceramic substrate via solder, and preferably, the other surface of the heat sink pattern copper plate having an arithmetic mean roughness Ra of less than 0.1 μm on one surface is joined to the other surface of the ceramic substrate via solder.

[0028] In the embodiment of the copper-ceramic circuit substrate, the thickness of the circuit pattern copper plate 114 is preferably 0.1 to 1.0 mm, and the arithmetic mean roughness Ra of one surface of the circuit pattern copper plate 114 is preferably 0.07 μm or less. In addition, the ceramic substrate 12 is preferably composed of aluminum nitride, silicon nitride or aluminum oxide, and the brazing material 18 preferably contains silver and copper, and contains Ti or Zr as an active metal. Example

[0029] Hereinafter, embodiments of the copper-ceramic circuit substrate and the method for manufacturing the same according to the present invention will be described in detail.

[0030] [Example 1] As a ceramic substrate, an aluminum nitride (AlN) substrate of 68 mm×68 mm×0.38 mm was prepared, and a dividing line (dividing groove) was provided on the AlN substrate so as to be divided into four substrates of 34 mm×34 mm×0.38 mm in size.

[0031] In addition, as a copper plate for circuit patterns and a copper plate for heat sink patterns, an oxygen-free copper plate (C1020-1 / 2H) of 70 mm × 70 mm × 0.15 mm was prepared, and the surface roughness of the copper plate was reduced by skin-pass rolling (adjusting the surface roughness of the roller and the load during rolling). Based on JIS B0601 (2001), the surface roughness of one surface of the copper plate was measured using a laser microscope (VK-X1000 produced by Keyence Co., Ltd.) with a cutoff value of λs = 2.5 μm, λc = 0.8 mm, and a (horizontal) measurement distance = 200 μm. The arithmetic roughness Ra of one surface of the copper plate was 0.028 μm. Furthermore, as a brazing material for bonding the ceramic substrate and the copper plate, an Ag—Cu—Ti based brazing material paste (mass ratio Ag:Cu:Ti=88:10:2) containing Ti as an active metal was prepared.

[0032] Next, the brazing material is applied to substantially the entire surfaces of both surfaces of the ceramic substrate by screen printing, and the brazing material is dried in the air to form the brazing material on both surfaces of the ceramic substrate.

[0033] Next, the copper plate for the circuit pattern and the copper plate for the heat sink pattern are respectively arranged on the solder on both sides of the ceramic substrate so that the other side of the copper plate abuts against the solder to form a laminate, and the laminate is heated in a vacuum furnace at 830°C and then cooled to produce a copper-ceramic bonding substrate in which the copper plate for the circuit pattern and the copper plate for the heat sink pattern are respectively bonded to both sides of the ceramic substrate via the solder.

[0034] Next, ultraviolet curing alkali stripping etching resist inks in the shapes of the circuit pattern and the heat sink pattern are respectively applied to the surfaces of the copper plate for the circuit pattern and the copper plate for the heat sink pattern of the above-mentioned copper-ceramic bonding substrate by screen printing, and cured by ultraviolet rays to form etching resists on the copper plate for the circuit pattern and the copper plate for the heat sink pattern.

[0035] Next, the unnecessary parts of the copper plate for the circuit pattern and the copper plate for the heat sink pattern (parts not covered by the etching resist) are etched away using an etching solution containing cupric chloride, and then the etching resist is stripped off using an aqueous sodium hydroxide solution to form the copper plate for the circuit pattern and the copper plate for the heat sink pattern.

[0036] Next, an etching solution containing ethylenediaminetetraacetic acid (EDTA) is used to etch away the unnecessary solder remaining around the circuit pattern copper plate and the heat sink pattern copper plate on the ceramic substrate, and then the ceramic substrate is divided into four along the dividing line set on the ceramic substrate to produce four copper-ceramic circuit substrates with the circuit pattern copper plate and the heat sink pattern copper plate respectively bonded to both sides of the ceramic substrate.

[0037] In addition, after forming an etching resist on the copper plate for circuit pattern and the copper plate for heat sink pattern of the above-mentioned copper-ceramic bonding substrate, before etching away unnecessary portions of the copper plate for circuit pattern and the copper plate for heat sink pattern, in order to evaluate the adhesion of the etching resist on the copper plate for circuit pattern, 10 of the above-mentioned copper-ceramic bonding substrates were prepared, and 25 2 mm square grids were formed on the surface of the etching resist on the copper plate for circuit pattern of each copper-ceramic bonding substrate using a cutter, and then an adhesive tape (transparent tape produced by NICHIBAN) was attached, and a cross-cut tape peeling test was performed according to JIS H8504, and the presence or absence of peeling of the etching resist was visually evaluated. As a result, among the 10 copper-ceramic bonding substrates, all 25 grids of the etching resist were not peeled off, and the adhesion of the etching resist was very good.

[0038] In addition, after forming an etching resist on the copper plate for circuit pattern and the copper plate for heat sink pattern of the above-mentioned copper-ceramic bonding substrate, before etching away unnecessary portions of the copper plate for circuit pattern and the copper plate for heat sink pattern, in order to evaluate the dimensional deviation of the etching resist on the copper plate for circuit pattern, 10 of the above-mentioned copper-ceramic bonding substrates were prepared, and the dimensions between adjacent etching resists (between circuit patterns) were measured using a high-precision image dimension measuring device (high-precision image dimension measuring device LM-1000 produced by Keyence Co., Ltd.). As a result, the average dimension (target value was 0.5 mm) between adjacent etching resists (between circuit patterns) was 0.533 mm, the difference between the maximum value and the minimum value (deviation range) was 0.007 mm, and the standard deviation was 0.003 mm. The dimensional deviation of the etching resist was very small.

[0039] In addition, in order to evaluate the dimensional deviation of the circuit pattern on the circuit pattern copper plate of the copper-ceramic circuit substrate produced, 10 of the above-mentioned copper-ceramic circuit substrates were prepared, and the dimensions between adjacent circuit patterns were measured using a high-precision image dimension measuring device (high-precision image dimension measuring device LM-1000 produced by Keyence Co., Ltd.). As a result, the average dimension between adjacent circuit patterns (target value was 0.8 mm) was 0.828 mm, the difference between the maximum and minimum values ​​(deviation range) was 0.026 mm, and the standard deviation was 0.009 mm. The dimensional deviation of the circuit pattern was very small.

[0040] [Example 2] As a ceramic substrate, an aluminum nitride (AlN) substrate of 68 mm × 68 mm × 0.64 mm in size was used, which was provided with dividing lines (dividing grooves) so that it could be divided into four substrates of 34 mm × 34 mm × 0.64 mm in size. As a copper plate for circuit patterns and a copper plate for heat sink patterns, an oxygen-free copper plate (C1020-1 / 2H) of 70 mm × 70 mm × 0.25 mm was used, and the surface roughness of the copper plate was reduced by skin-rolling processing so that the arithmetic mean roughness of one surface of the copper plate was 0.038 μm. Except for the above, a copper-ceramic bonding substrate was prepared in the same manner as in Example 1, and a copper-ceramic circuit substrate was prepared.

[0041] The adhesion of the etching resist on the copper plate for the circuit pattern of the copper-ceramic bonded substrate was evaluated by the same method as in Example 1. As a result, among the 10 copper-ceramic bonded substrates, none of the 25 grids of the etching resist peeled off, indicating that the adhesion of the etching resist was very good.

[0042] In addition, the dimensional deviation of the etching resist on the copper plate for the circuit pattern of the above-mentioned copper-ceramic bonding substrate was evaluated using the same method as in Example 1. As a result, the average size (target value was 0.5 mm) between adjacent etching resists (between circuit patterns) was 0.532 mm, the difference between the maximum and minimum values ​​(deviation range) was 0.008 mm, and the standard deviation was 0.004 mm. The dimensional deviation of the etching resist was very small.

[0043] In addition, the same method as in Example 1 was used to evaluate the dimensional deviation of the circuit pattern on the circuit pattern copper plate of the above-mentioned copper-ceramic circuit substrate. The results showed that the average size between adjacent circuit patterns (target value was 0.8 mm) was 0.829 mm, the difference between the maximum and minimum values ​​(deviation range) was 0.036 mm, and the standard deviation was 0.011 mm. The dimensional deviation of the circuit pattern was very small.

[0044] [Example 3] As a ceramic substrate, an aluminum nitride (AlN) substrate of 68 mm × 68 mm × 1.0 mm in size, which is provided with dividing lines (dividing grooves) so as to be divided into four substrates of 34 mm × 34 mm × 1.0 mm in size, is used. As a copper plate for circuit patterns and a copper plate for heat sink patterns, an oxygen-free copper plate (C1020-1 / 2H) of 70 mm × 70 mm × 0.40 mm in size is used, and a skin-rolling process is performed to reduce the surface roughness of the copper plate so that the arithmetic mean roughness of one surface of the copper plate is 0.047 μm. Except for the above, a copper-ceramic bonding substrate is prepared in the same manner as in Example 1, and a copper-ceramic circuit substrate is prepared.

[0045] The adhesion of the etching resist on the copper plate for the circuit pattern of the copper-ceramic bonded substrate was evaluated by the same method as in Example 1. As a result, among the 10 copper-ceramic bonded substrates, none of the 25 grids of the etching resist peeled off, indicating that the adhesion of the etching resist was very good.

[0046] In addition, the dimensional deviation of the etching resist on the copper plate for the circuit pattern of the above-mentioned copper-ceramic bonding substrate was evaluated using the same method as in Example 1. As a result, the average size (target value was 0.5 mm) between adjacent etching resists (between circuit patterns) was 0.528 mm, the difference between the maximum and minimum values ​​(deviation range) was 0.011 mm, and the standard deviation was 0.004 mm. The dimensional deviation of the etching resist was very small.

[0047] In addition, the same method as in Example 1 was used to evaluate the dimensional deviation of the circuit pattern on the circuit pattern copper plate of the above-mentioned copper-ceramic circuit substrate. The results showed that the average size between adjacent circuit patterns (target value was 0.8 mm) was 0.830 mm, the difference between the maximum and minimum values ​​(deviation range) was 0.042 mm, and the standard deviation was 0.013 mm. The dimensional deviation of the circuit pattern was very small.

[0048] [Example 4] As a ceramic substrate, a 68mm×68mm×0.32mm silicon nitride substrate with dividing lines (dividing grooves) so that it can be divided into four substrates of 34mm×34mm×0.32mm in size was used. As a copper plate for circuit patterns and a copper plate for heat sink patterns, an oxygen-free copper plate (C1020-1 / 2H) of 70mm×70mm×0.80mm was used, and the surface roughness of the copper plate was reduced by skin-rolling processing so that the arithmetic mean roughness of one surface of the copper plate was 0.092μm. Except for the above, the same method as in Example 1 was used to produce a copper-ceramic bonding substrate and a copper-ceramic circuit substrate.

[0049] The adhesion of the etching resist on the copper plate for the circuit pattern of the copper-ceramic bonded substrate was evaluated by the same method as in Example 1. As a result, among the 10 copper-ceramic bonded substrates, none of the 25 grids of the etching resist peeled off, indicating that the adhesion of the etching resist was very good.

[0050] In addition, the dimensional deviation of the etching resist on the copper plate for the circuit pattern of the above-mentioned copper-ceramic bonding substrate was evaluated using the same method as in Example 1. As a result, the average size (target value was 0.5 mm) between adjacent etching resists (between circuit patterns) was 0.535 mm, the difference between the maximum and minimum values ​​(deviation range) was 0.013 mm, and the standard deviation was 0.005 mm. The dimensional deviation of the etching resist was very small.

[0051] In addition, the same method as in Example 1 was used to evaluate the dimensional deviation of the circuit pattern on the circuit pattern copper plate of the above-mentioned copper-ceramic circuit substrate. The results showed that the average size between adjacent circuit patterns (target value was 0.8 mm) was 0.836 mm, the difference between the maximum and minimum values ​​(deviation range) was 0.052 mm, and the standard deviation was 0.014 mm. The dimensional deviation of the circuit pattern was very small.

[0052] [Comparative Example 1] As the copper plate for the circuit pattern and the copper plate for the heat sink pattern, an oxygen-free copper plate (C1020-1 / 2H) with a size of 70 mm × 70 mm × 0.25 mm and a surface arithmetic mean roughness Ra of 0.146 μm was used, and the surface of the copper plate was not subjected to skin-pass rolling. Except for the above, the same method as in Example 2 was used to produce a copper-ceramic joint substrate and a copper-ceramic circuit substrate.

[0053] The adhesion of the etching resist on the copper plate for the circuit pattern of the copper-ceramic bonded substrate was evaluated by the same method as in Example 1. As a result, among the 10 copper-ceramic bonded substrates, none of the 25 grids of the etching resist peeled off, indicating that the adhesion of the etching resist was very good.

[0054] In addition, the same method as in Example 1 was used to evaluate the dimensional deviation of the etching resist on the copper plate for the circuit pattern of the above-mentioned copper-ceramic bonding substrate. The results showed that the average size (target value was 0.5 mm) between adjacent etching resists (between circuit patterns) was 0.552 mm, the difference between the maximum and minimum values ​​(deviation range) was 0.060 mm, and the standard deviation was 0.014 mm. The dimensional deviation of the etching resist was large.

[0055] In addition, the same method as in Example 1 was used to evaluate the dimensional deviation of the circuit pattern on the copper plate of the circuit pattern of the above-mentioned copper-ceramic circuit substrate. The results showed that the average size of the adjacent circuit patterns (target value was 0.8 mm) was 0.850 mm, the difference between the maximum and minimum values ​​(deviation range) was 0.103 mm, and the standard deviation was 0.020 mm. The dimensional deviation of the circuit pattern was very large.

[0056] [Comparative Example 2] As the copper plate for the circuit pattern and the copper plate for the heat sink pattern, an oxygen-free copper plate (C1020-1 / 2H) with a size of 70 mm × 70 mm × 0.25 mm and a surface arithmetic mean roughness Ra of 0.246 μm was used, and the surface of the copper plate was not subjected to skin-pass rolling. Except for the above, the same method as in Example 2 was used to produce a copper-ceramic joint substrate and a copper-ceramic circuit substrate.

[0057] The adhesion of the etching resist on the copper plate for the circuit pattern of the copper-ceramic bonded substrate was evaluated by the same method as in Example 1. As a result, among the 10 copper-ceramic bonded substrates, none of the 25 grids of the etching resist peeled off, indicating that the adhesion of the etching resist was very good.

[0058] In addition, the same method as in Example 1 was used to evaluate the dimensional deviation of the etching resist on the copper plate for the circuit pattern of the above-mentioned copper-ceramic bonding substrate. The results showed that the average size (target value was 0.5 mm) between adjacent etching resists (between circuit patterns) was 0.550 mm, the difference between the maximum and minimum values ​​(deviation range) was 0.092 mm, and the standard deviation was 0.021 mm. The dimensional deviation of the etching resist was large.

[0059] In addition, the same method as in Example 1 was used to evaluate the dimensional deviation of the circuit pattern on the circuit pattern copper plate of the above-mentioned copper-ceramic circuit substrate. The results showed that the average size (target value was 0.8 mm) between adjacent circuit patterns was 0.855 mm, the difference between the maximum and minimum values ​​(deviation range) was 0.180 mm, and the standard deviation was 0.030 mm. The dimensional deviation of the circuit pattern was very large. Description of symbols

[0060] 10Copper-ceramic bonding substrate 12 Ceramic Substrate 14 Copper plate for circuit pattern 16 Copper plate for heat sink pattern 18 Brazing material 20 Circuit pattern shaped etching resist 22 Etching resist for heat sink pattern shape 100 copper-ceramic circuit substrate 114 Circuit Pattern Copper Plate 116 Radiator pattern copper plate 118 solder.

Claims

1. A method for manufacturing a copper-ceramic circuit substrate, characterized in that: A circuit pattern copper plate having an arithmetic mean roughness Ra of less than 0.1 μm on one surface is prepared, and the other surface of the circuit pattern copper plate is joined to one surface of a ceramic substrate via solder, and then an etching resist in the shape of a circuit pattern is formed on one surface of the circuit pattern copper plate, and a portion of the circuit pattern copper plate is etched to form a circuit pattern copper plate in the shape of a circuit pattern.

2. The method for manufacturing a copper-ceramic circuit substrate according to claim 1, wherein: The thickness of the circuit pattern copper plate is 0.1 to 1.0 mm.

3. The method for manufacturing a copper-ceramic circuit substrate according to claim 1, wherein: The circuit pattern copper plate is obtained by reducing the surface roughness of one surface of the copper plate by skin pass rolling or chemical polishing.

4. The method for manufacturing a copper-ceramic circuit substrate according to claim 1, wherein: The arithmetic mean roughness Ra of one surface of the circuit pattern copper plate is 0.07 μm or less.

5. The method for manufacturing a copper-ceramic circuit substrate according to claim 1, wherein: An etching resist in the shape of the circuit pattern is formed by printing an etching resist ink on one surface of the circuit pattern copper plate and then curing the ink.

6. The method for manufacturing a copper-ceramic circuit substrate according to claim 1, wherein: The ceramic substrate is made of aluminum nitride, silicon nitride or aluminum oxide.

7. The method for manufacturing a copper-ceramic circuit substrate according to claim 1, wherein: The solder contains silver and copper, and contains Ti or Zr as an active metal.

8. The method for manufacturing a copper-ceramic circuit substrate according to claim 1, wherein: When the other surface of the circuit pattern copper plate and one surface of the ceramic substrate are joined via solder, the heat sink pattern copper plate is joined to the other surface of the ceramic substrate via solder, an etching resist in the shape of a heat sink pattern is formed on the surface of the heat sink pattern copper plate, and a portion of the heat sink pattern copper plate is etched to form a heat sink pattern copper plate in the shape of a heat sink pattern.

9. A copper-ceramic circuit substrate, characterized in that: The other surface of the circuit pattern copper plate having one surface with an arithmetic mean roughness Ra of 0.1 μm or less is bonded to one surface of the ceramic substrate via a brazing material.

10. The copper-ceramic circuit substrate according to claim 9, characterized in that: The other surface of the heat sink pattern copper plate having one surface with an arithmetic mean roughness Ra of 0.1 μm or less is bonded to the other surface of the ceramic substrate via a brazing material.

11. The copper-ceramic circuit substrate according to claim 9, characterized in that: The thickness of the circuit pattern copper plate is 0.1-1.0 mm.

12. The copper-ceramic circuit substrate according to claim 9, characterized in that: The arithmetic mean roughness Ra of one surface of the circuit pattern copper plate is 0.07 μm or less.

13. The copper-ceramic circuit substrate according to claim 9, characterized in that: The ceramic substrate is made of aluminum nitride, silicon nitride or aluminum oxide.

14. The copper-ceramic circuit substrate according to claim 9, characterized in that: The solder contains silver and copper, and contains Ti or Zr as an active metal.

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