Wiring board, package for storing electronic component, brazing filler metal, and method for manufacturing wiring board

Abstract

This wiring board comprises: a substrate formed from ceramic; a metallized layer that has a first metal comprising at least one of tungsten, molybdenum, and manganese and is positioned on the substrate; an intermediate layer that contains the first metal, copper, platinum, and palladium and is positioned on the metallized layer; and a conductive layer that contains copper, platinum, and palladium and is positioned on the intermediate layer.

Description

Wiring board, electronic component housing package, brazing material, and method for manufacturing a wiring board

[0001] This disclosure relates to a wiring board, a package for housing electronic components, a brazing material, and a method for manufacturing a wiring board.

[0002] Japanese Patent Publication No. 61-119051 describes a substrate for a semiconductor device in which a first metal layer to a third metal layer are sequentially laminated on aluminum nitride.

[0003] The wiring board according to this disclosure comprises: a ceramic substrate; a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese and located on the substrate; an intermediate layer containing the first metal, copper, platinum, and palladium and located on the metallized layer; and a conductive layer containing copper, platinum, and palladium and located on the intermediate layer.

[0004] Another embodiment of the wiring board according to the present disclosure comprises: a ceramic substrate; a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese and located on the substrate; an intermediate layer containing the first metal, copper, and platinum and located on the metallized layer; and a conductive layer containing copper and platinum and located on the intermediate layer.

[0005] The electronic component housing package relating to this disclosure comprises the above-mentioned wiring board.

[0006] The brazing material relating to this disclosure is a brazing material that joins a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese to a composite or clad material of copper and tungsten, a composite or clad material of copper and molybdenum, or a metal member that is copper, wherein the total content of silver, copper, platinum, and palladium is 80 atom% or more, and it comprises a first part in which the silver content is higher than that of copper, and a second part in which the copper content is higher than that of silver, with palladium unevenly distributed in the first part and platinum unevenly distributed in the second part.

[0007] A method for manufacturing a wiring board according to the present disclosure comprises firing a ceramic substrate and a metallized layer located on the substrate and having a first metal consisting of at least one of tungsten, molybdenum, and manganese; forming a metal film mainly composed of platinum on the metallized layer; heating the substrate on which the metal film is formed in a reducing atmosphere to form an alloy layer containing the first metal and platinum on the metallized layer; forming a first conductive film mainly composed of palladium on the alloy layer; forming a second conductive film mainly composed of copper on the first conductive film; and heating the substrate on which the first and second conductive films are formed in a reducing atmosphere to diffuse the platinum in the alloy layer and the palladium in the first conductive film into the second conductive film.

[0008] Another embodiment of the present disclosure of a method for manufacturing a wiring board comprises firing a ceramic substrate and a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese and located on the substrate; forming a first conductive film mainly composed of platinum on the metallized layer; forming a second conductive film mainly composed of palladium on the first conductive film; heating the substrate on which the first and second conductive films are formed in a reducing atmosphere to form a layer of alloy containing the first metal, platinum, and palladium on the metallized layer; forming a third conductive film mainly composed of copper on the alloy layer; and diffusing the platinum and palladium from the alloy layer into the third conductive film by heating the substrate on which the alloy layer and the third conductive film are formed in a reducing atmosphere.

[0009] Another embodiment of the present disclosure of a method for manufacturing a wiring board comprises firing a ceramic substrate and a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese and located on the substrate; forming a metal film mainly composed of platinum on the metallized layer; forming an alloy layer containing the first metal and platinum on the metallized layer by heating the substrate on which the metal film is formed in a reducing atmosphere; forming a conductive film mainly composed of copper on the alloy layer; and diffusing the platinum from the alloy layer into the conductive film by heating the substrate on which the conductive film is formed in a reducing atmosphere.

[0010] This is a longitudinal cross-sectional view showing an electronic component housing package according to Embodiment 1 of the present disclosure. This is an enlarged cross-sectional view showing the first portion C1 of the wiring board in Figure 1. This is a diagram showing a cross-section of the analysis location of the wiring conductor in Example 1 of Embodiment 1. This is a diagram showing the distribution of tungsten (W) at the analysis location in Figure 3A. This is a diagram showing the distribution of platinum (Pt) at the analysis location in Figure 3A. This is a diagram showing the distribution of copper (Cu) at the analysis location in Figure 3A. This is an enlarged cross-sectional view showing the second portion C2 of the wiring board in Figure 1. This is a diagram showing a cross-section of the analysis location of the wiring conductor in Example 2 of Embodiment 1. This is a diagram showing the distribution of tungsten (W) at the analysis location in Figure 5A. This is a diagram showing the distribution of platinum (Pt) at the analysis location in Figure 5A. This is a diagram showing the distribution of copper (Cu) at the analysis location in Figure 5A. This is a diagram showing the distribution of silver (Ag) at the analysis location in Figure 5A. This is an enlarged cross-sectional view showing the third portion C3 of the wiring board in Figure 1. This is a flow chart showing an example of a method for manufacturing the wiring board of Embodiment 1. This is a diagram showing a cross-section of the analysis location of the wiring conductor in Example 3 of Embodiment 2. This figure shows the distribution of tungsten (W) at the analysis site of the wiring conductor of Example 3. This figure shows the distribution of platinum (Pt) at the analysis site of the wiring conductor of Example 3. This figure shows the distribution of palladium (Pd) at the analysis site of the wiring conductor of Example 3. This figure shows the distribution of copper (Cu) at the analysis site of the wiring conductor of Example 3. This figure shows a cross-section of the wiring conductor of Example 4 in Embodiment 2. This figure shows the distribution of tungsten (W) at the analysis site of the wiring conductor of Example 4. This figure shows the distribution of platinum (Pt) at the analysis site of the wiring conductor of Example 4. This figure shows the distribution of palladium (Pd) at the analysis site of the wiring conductor of Example 4. This figure shows the distribution of copper (Cu) at the analysis site of the wiring conductor of Example 4. This figure shows the distribution of silver (Ag) at the analysis site of the wiring conductor of Example 4. This is a flow chart showing an example of a manufacturing method for a wiring substrate of Embodiment 2. This figure shows a cross-section of the analysis site in the wiring conductor of Embodiment 3 before the first heating step and the copper film formation step. This figure shows the distribution of tungsten (W) at the analysis site in Figure 14A. This figure shows the distribution of platinum (Pt) at the analysis site in Figure 14A. This figure shows the distribution of palladium (Pd) at the analysis site in Figure 14A.This figure shows a cross-section of the analysis location in the wiring conductor of Embodiment 3, before the copper film deposition process and after the first heating process. This figure shows the distribution of tungsten (W) at the analysis location in Figure 16A. This figure shows the distribution of platinum (Pt) at the analysis location in Figure 16A. This figure shows the distribution of palladium (Pd) at the analysis location in Figure 16A. This is an enlarged cross-sectional view showing the second part C2 of the wiring substrate in Embodiment 3. This figure shows a cross-section of the analysis location in the second part C2 of Embodiment 3. This figure shows the distribution of silver (Ag) at the analysis location in Figure 17A. This figure shows the distribution of copper (Cu) at the analysis location in Figure 17A. This figure shows the distribution of palladium (Pd) at the analysis location in Figure 17A. This figure shows the distribution of platinum (Pt) at the analysis location in Figure 17A. This figure shows the distribution of tungsten (W) at the analysis location in Figure 17A. This is a flow chart showing an example of a manufacturing method for the wiring substrate of Embodiment 3.

[0011] Embodiments of this disclosure will be described in detail below with reference to the drawings. In the following, "content" means atomic ratio.

[0012] (Embodiment 1) Figure 1 is a longitudinal cross-sectional view showing an electronic component housing package 100 according to Embodiment 1 of the present disclosure. The electronic component housing package 100 of this embodiment is intended to be used in devices that require low magnetism or non-magnetic properties. The electronic component housing package 100 comprises a low-magnetic or non-magnetic wiring board 10.

[0013] The configuration of the electronic component housing package 100 can be changed in various ways. In the example shown in Figure 1, it has a metal member 110 having a mounting area 101 for electronic components 300, and a wiring board 10 having an opening 120 that surrounds the mounting area 101 from the horizontal direction. The wiring board 10 is joined (specifically brazed) to the metal member 110 via a brazing material 130. The combined configuration of the metal member 110 and the wiring board 10 may be considered as a single wiring board 10.

[0014] The wiring board 10 comprises a ceramic substrate 11 and wiring conductors 16 and 16B located inside and on the surface of the substrate 11. One of the wiring conductors 16B corresponds to a wiring conductor to which a brazing material 130 is joined. The wiring conductors 16 and 16B may be conductors having a desired wiring pattern. The wiring conductor 16 may have an electrode region 102 that is electrically connected to the electrodes of the electronic component 300. The electrode region 102 may be connected to the electrodes of the electronic component 300 via an electrical bonding member 140 such as a bonding wire or solder.

[0015] The substrate 11 is made of alumina ceramics (Al ２ O ３ ), aluminum nitride ceramics (AlN), silicon nitride ceramics (Si ３ N ４ The substrate 11 may be a high-temperature co-fired ceramic (HTCC) such as glass ceramics.

[0016] <Wiring Conductor 16> Figure 2 is an enlarged cross-sectional view showing the first portion C1 of the wiring substrate 10 in Figure 1. The wiring conductor 16 includes a metallized layer 161 located on the surface of the substrate 11 and fired simultaneously with the substrate 11, an intermediate layer 162 located on the metallized layer 161, and a conductive layer 163 containing copper (Cu) located on the intermediate layer 162. In the above, the conductive layer 163 is considered to be above the substrate 11.

[0017] The wiring conductor 16 located inside the substrate 11 may have the same composition as the metallized layer 161 and may be fired at the same time as the substrate 11.

[0018] The metallized layer 161 has a first metal consisting of at least one of tungsten (W), molybdenum (Mo), and manganese (Mn). The first metal has temperature characteristics that allow it to be fired together with the ceramics. The metallized layer 161 may have a first metal content of 80 atom% (atomic percent) or more. The content of the first metal refers to the total content of multiple metals if the first metal contains multiple types of metals. In the example in Figure 1, the metallized layer 161 has tungsten as the first metal, and the tungsten content is 80 atom% or more.

[0019] The intermediate layer 162 may contain the first metal, copper, and platinum (Pt). Specifically, the intermediate layer 162 may contain an alloy of the first metal, copper, and platinum, and the alloy may be present in a content of 80 atom% or more.

[0020] The conductive layer 163 may contain copper and platinum. Specifically, the total content of copper and platinum in the conductive layer 163 may be 80 atom% or more. In the conductive layer 163, the copper content may be higher than the platinum content. The platinum is diffused and distributed throughout the conductive layer 163.

[0021] With the above-described wiring conductor 16, high adhesion between the metallized layer 161 and the substrate 11 can be easily achieved due to the temperature characteristics of the first metal. Furthermore, the interposition of an intermediate layer 162 containing the components of the metallized layer 161 and the conductive layer 163 provides high adhesion from the metallized layer 161 to the conductive layer 163. Therefore, high adhesion between the substrate 11 and the wiring conductor 16 can be obtained.

[0022] Furthermore, with the above-described wiring conductor 16, the composition of the metallized layer 161, the intermediate layer 162, and the conductive layer 163 can reduce or eliminate magnetic metals. Therefore, low magnetism or non-magnetic properties of the wiring substrate 10 can be achieved.

[0023] Furthermore, with the above-described wiring conductor 16, a large proportion of copper can be included as a component of the conductive layer 163. Therefore, the electrical resistance of the conductive layer 163 can be lowered while keeping material costs low.

[0024] Furthermore, with the above-described wiring conductor 16, platinum is diffused and distributed within the copper conductive layer 163. Therefore, the corrosion resistance of the copper-containing conductive layer 163 can be improved.

[0025] The intermediate layer 162 may include a first intermediate layer 162a and a second intermediate layer 162b having different copper content. The first intermediate layer 162a may be located closer to the metallization layer 161 than the second intermediate layer 162b, and the second intermediate layer 162b may be located closer to the conductive layer 163 than the first intermediate layer 162a. The copper content of the second intermediate layer 162b may be higher than that of the first intermediate layer 162a. The difference in copper content between the first intermediate layer 162a and the second intermediate layer 162b may be 5 atom% or more, or 10 atom% or more.

[0026] The content of the first metal may differ between the first intermediate layer 162a and the second intermediate layer 162b, with the first intermediate layer 162a having a higher content than the second intermediate layer 162b. The difference in the content of the first metal between the first intermediate layer 162a and the second intermediate layer 162b may be 5 atom% or more, or 10 atom% or more.

[0027] The intermediate layer 162 may have a copper concentration gradient in which the copper content decreases from the area closer to the conductive layer 163 to the area closer to the metallized layer 161.

[0028] With the above-described wiring conductor 16 configuration, the compositional change becomes gradual in the intermediate layer 162 and above and below the intermediate layer 162, and the adhesion between the metallized layer 161 and the conductive layer 163 by the intermediate layer 162 can be further improved.

[0029] <Specific Example 1 of Wiring Conductor 16> Next, as Example 1 of Embodiment 1, a specific example of a wiring conductor 16 having a metallized layer 161, an intermediate layer 162, and a conductive layer 163 is shown. In Example 1, tungsten is used for the first metal.

[0030] Figures 3A to 3D show the distribution of each component in the wiring conductor 16 of Example 1. Figure 3A shows a cross-section of the analysis area, Figure 3B shows the distribution of tungsten (W) at the analysis area, Figure 3C shows the distribution of platinum (Pt) at the analysis area, and Figure 3D shows the distribution of copper (Cu) at the analysis area. Figure 3A is a simplified SEM (Scanning Electron Microscope) image of the analysis area. Figures 3B to 3D are simplified images obtained by mapping the atomic ratio of the relevant atoms, which is the measurement result of EDS (Energy Dispersive X-ray Spectroscopy), onto the two-dimensional coordinates of the analysis area.

[0031] In the SEM image in Figure 3A, differences in components appear as differences in contrast. In the images in Figures 3B to 3D, the brightness represents the atomic ratio of the corresponding component. Higher brightness indicates a higher atomic ratio.

[0032] As shown in Figure 3A, in the wiring conductor 16 of Example 1, an intermediate layer 162 with a different composition is located between a metallized layer 161, which is mainly composed of a first metal, and a conductive layer 163, which is mainly composed of copper.

[0033] In the intermediate layer 162, as shown in Figure 3B, the first metal is distributed at a lower concentration than in the metallization layer 161. Furthermore, in the intermediate layer 162, as shown in Figure 3D, copper is distributed at a lower concentration than in the conductive layer 163. In addition, as shown in Figure 3C, platinum is distributed in both the conductive layer 163 and the intermediate layer 162. These results indicate that the intermediate layer 162 contains the first metal, copper, and platinum.

[0034] Furthermore, as shown in FIG. 3A, the intermediate layer 162 of Example 1 includes a first intermediate layer 162a and a second intermediate layer 162b having different component ratios from each other. Most of the first intermediate layer 162a is located closer to the metallized layer 161, and most of the second intermediate layer 162b is located closer to the conductive layer 163. In the measurement result of EDS, it is shown that the content rate of the first metal is higher in the first intermediate layer 162a than in the second intermediate layer 162b, and the content rate of copper is higher in the second intermediate layer 162b than in the first intermediate layer 162a. A region A1 in which the contrast gradually changes is included between the first intermediate layer 162a and the second intermediate layer 162b in FIG. 3A. The region A1 corresponds to a region where copper and the first metal have a concentration gradient in the intermediate layer 162. The concentration gradient is a gradient in which the content rate of copper increases and the content rate of the first metal decreases from the side closer to the metallized layer 161 to the side closer to the conductive layer 163.

[0035] The intermediate layer 162 of Example 1 further includes a site A11 having the same components and the same component ratio as the conductive layer 163, and a site A12 where the first intermediate layer 162a is interrupted with a void therebetween. As in the configuration of Example 1 described above, the intermediate layer 162 of the present embodiment may include a site equivalent to the conductive layer 163 and one or both of the interrupted sites.

[0036] <Component Ratio of Wiring Conductor 16> Next, an example of the component ratio of the wiring conductor 16 according to the present embodiment is shown. The following component ratio is a value estimated based on the result of EDS analysis of the wiring conductor 16 of Example 1 in which good characteristics were obtained. The estimated value corresponds to a value obtained by giving a width that does not cause a significant change in characteristics to the value of the component ratio of Example 1 in which good characteristics were obtained.

[0037] With the components and the component ratio, in addition to the characteristics of low magnetism or non-magnetism, low resistance, and low cost, higher adhesion of the conductive layer 163 to the metallized layer 161 can be realized. Note that the above component ratio is not extracted from the range in which the effect is obtained, and the effect does not decrease steeply even if the above component ratio is deviated.

[0038] <Welded Wiring Conductor 16B>FIG. 4 is an enlarged cross-sectional view showing the second part C2 of the wiring board 10 in FIG. 1. The second part C2 is the part where the wiring conductor 16B joined to the brazing material 130 is located.

[0039] As shown in FIG. 4, the wiring conductor 16B brazed to the metal member 110 may include a metallization layer 161 located on the surface of the base 11, an intermediate layer 162B located on the metallization layer 161, and a conductive layer 163B containing copper and platinum and located on the intermediate layer 162B. In the above, when looking from the base 11 towards the conductive layer 163B, it is regarded as upward.

[0040] The metallization layer 161 is equivalent to the metallization layer 161 of the wiring conductor 16 without brazing described above (see FIG. 2).

[0041] The brazing material 130 may have a composition in which the total component ratio of silver (Ag), copper, and platinum is 80 atom% or more. In the brazing material 130 of this composition, during the solidification process, two components are separated and undergo a phase change. As shown in FIG. 4, an Ag-rich part (corresponding to the first part) B11 with a higher silver component ratio and a Cu-rich part (corresponding to the second part) B12 with a higher copper component ratio may be included. The Ag-rich part B11 may contain 70 atom% or more of silver, and the Cu-rich part B12 may contain 70 atom% or more of copper. The Ag-rich part B11 and the Cu-rich part B12 may together occupy 90% or more in terms of the area ratio in an arbitrary cross-section of the brazing material 130. Platinum may be unevenly distributed in the Cu-rich part B12. Hereinafter, an example in which the brazing material 130 of this composition is used is shown.

[0042] In addition, as the brazing material 130, a low-melting-point brazing material containing gold and tin may be used.

[0043] The metal member 110 (see FIG. 1) may be a composite material or clad material of copper and tungsten, a composite material or clad material of copper and molybdenum, or copper.

[0044] The conductive layer 163B may be mostly integrated with the brazing material 130. The conductive layer 163B includes an Ag-rich portion B11 and a Cu-rich portion B12, and the Ag-rich portion B11 and the Cu-rich portion B12 may account for 90% or more of the area ratio in any cross-section. In the conductive layer 163B, platinum may be unevenly distributed in the Cu-rich portion B12. Platinum may also be distributed in the Ag-rich portion B11. The concentration of platinum distributed in the Cu-rich portion B12 may be higher than the concentration of platinum distributed in the Ag-rich portion B11. In the conductive layer 163, the copper content may be higher than the platinum content.

[0045] The intermediate layer 162B may have the same configuration as the first intermediate layer 162a (see Figure 2) described above. During brazing, the second intermediate layer 162b of the intermediate layer 162 of the wiring conductor 16 described above is integrated with the conductive layer 163 and the brazing material 130, while a part of the first intermediate layer 162a remains, and this remaining part of the first intermediate layer 162a may constitute the intermediate layer 162B.

[0046] With the above-described wiring conductor 16B, the composition of the brazing material 130, metallized layer 161, intermediate layer 162B, and conductive layer 163B can reduce or eliminate magnetic metals. Therefore, low magnetism or non-magnetic properties can be achieved for the wiring board 10 and the electronic component housing package 100.

[0047] Furthermore, with the above-described wiring conductor 16B, high adhesion between the metallized layer 161 and the substrate 11 can be easily achieved due to the temperature characteristics of the first metal. In addition, the interposition of the intermediate layer 162B, which contains the components of the metallized layer 161 and the components of the conductive layer 163B, provides high adhesion from the metallized layer 161 to the conductive layer 163B. Thus, high adhesion between the substrate 11 and the wiring conductor 16B can be obtained. Furthermore, due to the components of the conductive layer 163B and the brazing material 130, the conductive layer 163B and the brazing material 130 are integrated, resulting in high bonding strength of the brazing material 130. Thus, high adhesion between the substrate 11 and the wiring conductor 16, as well as high bonding strength between the wiring substrate 10 and the metal member 110, can be achieved.

[0048] Furthermore, with the above-described wiring conductor 16B, a large proportion of copper can be included as a component of the conductive layer 163B. Therefore, the electrical resistance of the conductive layer 163 can be lowered while keeping material costs low.

[0049] Furthermore, with the above-described wiring conductor 16B, a large amount of platinum is distributed in the Cu-rich portion B12 of the conductive layer 163B integrated with the brazing material 130. Therefore, the corrosion resistance of the copper-containing wiring conductor 16B and the brazing material 130 can be improved.

[0050] <Specific Example 2 of Brazed Wiring Conductor 16B> Next, as Example 2 of Embodiment 1, a specific example of a brazed wiring conductor 16B is shown. In Example 2, tungsten is used for the first metal.

[0051] Figures 5A to 5C, 6A, and 6B show the distribution of each component in the wiring conductor 16B of Example 2. Figure 5A shows a cross-section of the analysis site, Figure 5B shows the distribution of tungsten (W) at the analysis site, Figure 5C shows the distribution of platinum (Pt) at the analysis site, Figure 6A shows the distribution of copper (Cu) at the analysis site, and Figure 6B shows the distribution of silver (Ag) at the analysis site. Figure 5A is a simplified SEM image of the analysis site. Figures 5B to 6B are simplified images obtained by mapping the atomic ratio of the corresponding atoms, which are the measurement results of EDS, onto the two-dimensional coordinates of the analysis site.

[0052] In the SEM image in Figure 5A, differences in components appear as differences in contrast. In the images in Figures 5B to 6B, the brightness represents the atomic ratio of the corresponding component. Higher brightness indicates a higher atomic ratio.

[0053] As shown in Figure 5A, in the wiring conductor 16B of Embodiment 2, an intermediate layer 162B with a different composition is located between a metallized layer 161, which is mainly composed of a first metal, and a conductive layer 163B containing copper. As shown in Figure 5A, the intermediate layer 162B may not be located across the entire metallized layer 161, but rather distributed over a portion of the metallized layer 161. In Figure 5A, the intermediate layer 162B, which is divided into multiple parts, is located between the Ag-rich portion B11 and the metallized layer 161, and between the Cu-rich portion B12 and the metallized layer 161, respectively.

[0054] In the conductive layer 163B of Example 2, which is integrated with the brazing material 130, separate Ag-rich portion B11 and Cu-rich portion B12 are located as shown in Figures 5C to 6B. Platinum is distributed more abundantly in the Cu-rich portion B12 than in the Ag-rich portion B11.

[0055] <Component Ratio of Wiring Conductor 16B> Next, an example of the component ratio of the wiring conductor 16B according to this embodiment is shown. Below, the component ratio of the conductive layer 163B, which is integrated with the brazing material 130, is shown, which differs from the unbrazed wiring conductor 16 described above. The component ratios below are estimated values ​​based on the results of EDS analysis of the wiring conductor 16B of Example 2, which obtained good characteristics. The estimated values ​​correspond to values ​​with a range that does not significantly affect the characteristics, compared to the component ratio values ​​of Example 2, which obtained good characteristics.

[0056] The components and their ratios enable low magnetism or non-magnetism, as well as low resistance and low cost, while also achieving higher adhesion of the conductive layer 163B to the metallized layer 161 and higher brazing strength to the wiring board 10. It should be noted that the above component ratios are not a selection of the range in which the effect is obtained, and the effect does not drastically decrease even if the component ratios deviate from the above ranges.

[0057] <Wiring conductor 16 in electrode region 102> Figure 7 is an enlarged cross-sectional view showing the third portion C3 of the wiring board 10 in Figure 1. The third portion C3 corresponds to the electrode region 102.

[0058] The wiring conductor 16 may have a gold-based adhesive layer 165 above the conductive layer 163 in the electrode region 102. "Gold-based adhesive" means that the gold content is 80 atom% or more. The adhesive layer 165 is a layer intended to bond the electrical bonding member 140. The adhesive layer 165 can improve the bonding performance of the bonding member 140 (see Figure 1).

[0059] The wiring conductor 16 may further have a barrier layer 164 located between the adherend layer 165 and the conductive layer 163. The barrier layer 164 may be mainly composed of platinum, palladium (Pd), or an alloy of platinum and palladium. The barrier layer 164 reduces the thermal diffusion of copper from the conductive layer 163 to the adherend layer 165, thereby maintaining the high adhesive performance of the adherend layer 165. Alternatively, the wiring conductor 16 may not have a barrier layer 164, and the adherend layer 165 may be directly located on the conductive layer 163.

[0060] <Method for Manufacturing a Wired Board> Figure 8 is a flowchart showing an example of a method for manufacturing a wired board 10 according to Embodiment 1. Here, a wired board 10 in which the wiring conductors 16 are located on one surface of the substrate 11 is shown as an example, but the wiring conductors 16 may be located on multiple surfaces of the substrate 11, and the wiring conductors 16 may have various wiring patterns. If wiring patterns are included, various known patterning processes may be included.

[0061] A method for manufacturing a wiring board 10 may include a firing step J1 for firing a substrate 11 and a metallization layer 161, a coating step J2 for forming a platinum-based coating 181 on the metallization layer 161, a first heating step J3 for allowing the platinum of the coating 181 and the first metal of the metallization layer 161 to permeate each other, a film formation step J4 for forming a copper-based conductive film 183 on an alloy layer 182 formed in the first heating step J3, and a second heating step J5 for allowing the components to diffuse between the conductive film 183 and the alloy layer 182.

[0062] In firing process J1, ceramic green sheets are laminated, and a molded body is formed in which the metallized layer 161 and the metal material that will become the internal wiring conductor are arranged in a desired wiring pattern, and the molded body is fired.

[0063] In the coating process J2, a platinum-based coating 181 is formed on the metallized layer 161 by plating. The plating can be performed using either electrolytic plating or electroless plating. When using electroless plating, palladium may be included as a trace component as a catalytically active metal before plating.

[0064] The first heating step J3 involves heating the substrate that has undergone the coating step J2, for example, N ２ +H ２ The material is heated in a reducing atmosphere 191, for example, at 500°C to 900°C. This heating causes the first metal of the metallized layer 161 to diffuse into the coating 181, forming an alloy layer 182 of the first metal and platinum.

[0065] In the film formation step J4, a conductive film 183 mainly composed of copper is formed on the alloy layer 182 by plating. The plating can be done by electrolytic plating or electroless plating. When using electroless plating, palladium may be included as a trace component as a catalytic active metal before plating.

[0066] In the second heating step J5, the substrate that has gone through the film formation step J4 is heated, for example, N ２ +H ２ The mixture is heated in a reducing atmosphere 192, for example, at 400°C to 850°C. This heating causes the platinum in the alloy layer 182 to diffuse into the conductive film 183, and the copper in the conductive film 183 to diffuse into the alloy layer 182, forming the intermediate layer 162 and the conductive layer 163.

[0067] The wiring board 10 of Embodiment 1 can be manufactured using the manufacturing method described above. Note that the above manufacturing method is just one example, and the wiring board 10 can be manufactured by changing several factors, such as the components of each layer and film, the parameters of each process, and the process procedure.

[0068] (Embodiment 2) The electronic component housing package 100 of Embodiment 2 may be the same as that of Embodiment 1, except that the configuration of conductors in multiple parts is different. Next, a configuration different from that of Embodiment 1 will be described. The electronic component housing package 100 of Embodiment 2 has the same structure as that of Figures 1, 2, 4, and 7 described in Embodiment 1. Figure 2 is an enlarged cross-sectional view showing the first part C1 of the wiring board 10 in Figure 1.

[0069] <Wiring Conductor 16> As shown in Figure 2, the wiring conductor 16 located at the first part C1 of Embodiment 2 includes a metallized layer 161 located on the surface of the substrate 11 and fired simultaneously with the substrate 11, an intermediate layer 162 located on the metallized layer 161, and a conductive layer 163 containing copper (Cu) located on the intermediate layer 162. In the above, the conductive layer 163 is considered to be above the substrate 11.

[0070] The metallized layer 161 has a first metal consisting of at least one of tungsten (W), molybdenum (Mo), and manganese (Mn). The first metal has temperature characteristics that allow it to be fired together with the ceramics. The metallized layer 161 may have a first metal content of 80 atom% (atomic percent) or more. The content of the first metal refers to the total content of multiple metals if the first metal contains multiple types of metals. In the example in Figure 1, the metallized layer 161 has tungsten as the first metal, and the tungsten content is 80 atom% or more. The metallized layer 161 may also contain palladium (Pd).

[0071] The intermediate layer 162 may contain a first metal, copper, platinum (Pt), and palladium. Specifically, the intermediate layer 162 may contain an alloy of the first metal, copper, platinum, and palladium, with the alloy containing 80 atom% or more. The thickness of the intermediate layer 162 may be less than the thickness of the conductive layer 163, more specifically half or less, and more specifically one-third or less. The thickness of the intermediate layer 162 may be less than the thickness of the metallization layer 161, more specifically half or less, and more specifically one-third or less. The boundary between the intermediate layer 162 and the conductive layer 163 can be defined as the position where the content of the first metal decreases sharply, and the boundary between the intermediate layer 162 and the metallization layer 161 can be defined as the position where the content of copper and platinum decreases sharply.

[0072] The conductive layer 163 may contain copper, platinum, and palladium. Specifically, the total content of copper, platinum, and palladium in the conductive layer 163 may be 80 atom% or more. In the conductive layer 163, the copper content may be higher than the platinum content, and the copper content may be higher than the palladium content. In the conductive layer 163, the copper content may be higher than the combined content of platinum and palladium. In the conductive layer 163, the platinum content may be higher than the palladium content. Platinum and palladium are diffused and distributed throughout the conductive layer 163.

[0073] With the above-described wiring conductor 16, high adhesion between the metallized layer 161 and the substrate 11 can be easily achieved due to the temperature characteristics of the first metal. Furthermore, the interposition of an intermediate layer 162 containing the components of the metallized layer 161 and the conductive layer 163 provides high adhesion from the metallized layer 161 to the conductive layer 163. Therefore, high adhesion between the substrate 11 and the wiring conductor 16 can be obtained.

[0074] Furthermore, with the above-described wiring conductor 16, the composition of the metallized layer 161, the intermediate layer 162, and the conductive layer 163 can reduce or eliminate magnetic metals. Therefore, low magnetism or non-magnetic properties of the wiring substrate 10 can be achieved.

[0075] Furthermore, with the above-described wiring conductor 16, a large proportion of copper can be included as a component of the conductive layer 163. Therefore, the electrical resistance of the conductive layer 163 can be lowered while keeping material costs low.

[0076] Furthermore, with the above-described wiring conductor 16, platinum and palladium are diffused and distributed in the copper conductive layer 163. Therefore, the corrosion resistance and heat resistance of the copper-containing conductive layer 163 can be improved. In addition, with the above-described wiring conductor 16, the intermediate layer 162 is thinner than the conductive layer 163. The thinness of the intermediate layer 162 indicates that excessive diffusion of platinum from the conductive layer 163 to the metallized layer 161 is suppressed when forming the intermediate layer 162 and the conductive layer 163. Therefore, the amount of platinum and palladium used can be reduced while increasing the platinum and palladium content in the conductive layer 163. Consequently, the corrosion resistance and heat resistance of the copper-containing conductive layer 163 can be further improved. The effect of suppressing excessive diffusion of platinum is obtained by palladium.

[0077] The intermediate layer 162 may have a structure in which the copper content increases gradually or sequentially from the metallized layer 161 towards the conductive layer 163, and the content of the first metal decreases gradually or sequentially.

[0078] Specifically, the intermediate layer 162 may include a first intermediate layer 162a and a second intermediate layer 162b having different copper contents. The first intermediate layer 162a may be located closer to the metallization layer 161 than the second intermediate layer 162b, and the second intermediate layer 162b may be located closer to the conductive layer 163 than the first intermediate layer 162a. The copper content of the second intermediate layer 162b may be higher than that of the first intermediate layer 162a. The difference in copper content between the first intermediate layer 162a and the second intermediate layer 162b may be 5 atom% or more, or 10 atom% or more. The platinum content of the second intermediate layer 162b may be higher than that of the first intermediate layer 162a. The platinum content of the first intermediate layer 162a may be 90% or less of the platinum content of the second intermediate layer 162b. The palladium content may be higher in the second intermediate layer 162b than in the first intermediate layer 162a. The palladium content of the first intermediate layer 162a may be 90% or less of the palladium content of the second intermediate layer 162b.

[0079] The content of the first metal may differ between the first intermediate layer 162a and the second intermediate layer 162b, with the first intermediate layer 162a having a higher content than the second intermediate layer 162b. The difference in the content of the first metal between the first intermediate layer 162a and the second intermediate layer 162b may be 5 atom% or more, or 10 atom% or more.

[0080] With the above-described wiring conductor 16 configuration, the compositional change becomes gradual in the intermediate layer 162 and above and below the intermediate layer 162, and the adhesion between the metallized layer 161 and the conductive layer 163 by the intermediate layer 162 can be further improved.

[0081] <Specific Example 3 of Wiring Conductor 16> Next, as Example 3 of Embodiment 2, a specific example of a wiring conductor 16 having a metallized layer 161, an intermediate layer 162, and a conductive layer 163 is shown. In Example 3, tungsten is used for the first metal.

[0082] Figures 9A to 9C, 10A, and 10B show the distribution of each component in the wiring conductor 16 of Example 3. Figure 9A shows a cross-section of the analysis area, Figure 9B shows the distribution of tungsten (W) at the analysis area, Figure 9C shows the distribution of platinum (Pt) at the analysis area, Figure 10A shows the distribution of palladium (Pd) at the analysis area, and Figure 10B shows the distribution of copper (Cu) at the analysis area. Figure 9A is a simplified SEM (Scanning Electron Microscope) image of the analysis area. Figures 9B to 10B are simplified images obtained by mapping the atomic ratio of the relevant atoms, which is the measurement result of EDS (Energy Dispersive X-ray Spectroscopy), onto the two-dimensional coordinates of the analysis area.

[0083] In the SEM image in Figure 9A, differences in components appear as differences in contrast. In the images in Figures 9B to 10B, the brightness represents the atomic ratio of the corresponding component. Higher brightness indicates a higher atomic ratio.

[0084] As shown in Figure 9A, in the wiring conductor 16 of Example 3, an intermediate layer 162 with a different composition is located between a metallized layer 161, which is mainly composed of a first metal, and a conductive layer 163, which is mainly composed of copper.

[0085] In the intermediate layer 162, as shown in Figure 9B, the first metal is distributed at a lower concentration than in the metallization layer 161. Furthermore, in the intermediate layer 162, as shown in Figure 10B, copper is distributed at a lower concentration than in the conductive layer 163. In addition, as shown in Figures 9C and 10A, platinum and palladium are distributed in both the conductive layer 163 and the intermediate layer 162 at lower concentrations than in the conductive layer 163. These results indicate that the intermediate layer 162 contains the first metal, copper, platinum, and palladium.

[0086] Furthermore, as shown in Figure 9A, the intermediate layer 162 of Example 3 includes a first intermediate layer 162a and a second intermediate layer 162b, which have different component ratios. Most of the first intermediate layer 162a is located closer to the metallization layer 161, and most of the second intermediate layer 162b is located closer to the conductive layer 163. EDS measurement results show that the content of the first metal is higher in the first intermediate layer 162a than in the second intermediate layer 162b, and the copper content is higher in the second intermediate layer 162b than in the first intermediate layer 162a.

[0087] The intermediate layer 162 of Example 3 includes a gap or a portion D1 that is interrupted by a component of the conductive layer 163. As in the configuration of Example 3, the intermediate layer 162 of this embodiment described above may include a gap or a portion that is interrupted by a component of the conductive layer 163.

[0088] As shown in Figures 9C and 10B, in the wiring conductor 16 of Example 3, the diffusion and distribution of copper and platinum into the metallization layer 161 are very small. On the other hand, as shown in Figure 10A, palladium diffuses and is distributed into the metallization layer 161 in greater quantities than copper or platinum. The palladium has the effect of suppressing the excessive diffusion of platinum and copper into the metallization layer 161.

[0089] <Component Ratio of Wiring Conductor 16> Next, an example of the component ratio of the wiring conductor 16 according to this embodiment is shown. The component ratios below are estimated values ​​based on the results of EDS analysis of the wiring conductor 16 of Example 3, which obtained good characteristics. The estimated values ​​correspond to values ​​that have a range that does not significantly affect the characteristics, compared to the component ratio values ​​of Example 3, which obtained good characteristics.

[0090] The components and their ratios enable the realization of low magnetism or non-magnetic properties, as well as low resistance and low cost, and higher adhesion of the conductive layer 163 to the metallized layer 161. Furthermore, by increasing the platinum and palladium content in the conductive layer 163 while reducing the amount of platinum and palladium used, the corrosion resistance and heat resistance of the copper-containing conductive layer 163 can be further improved. It should be noted that the above component ratios are not a selection of the range in which the effect is obtained, and the effect does not decrease sharply even if the component ratios deviate from the above ratios.

[0091] <Brazed wiring conductor 16B> The second part C2 of the wiring board 10 shown in Figure 4 is the part where the wiring conductor 16B, which is joined to the brazing material 130, is located.

[0092] The wiring conductor 16B brazed to the metal member 110 may include, as shown in Figure 4, a metallized layer 161 located on the surface of the substrate 11, an intermediate layer 162B located on the metallized layer 161, and a conductive layer 163B containing copper, platinum, and palladium located on the intermediate layer 162B. In the above, the conductive layer 163B is considered to be above the substrate 11.

[0093] The metallized layer 161 is equivalent to the metallized layer 161 of the brazed wiring conductor 16 described above (see Figure 2).

[0094] The brazing material 130 may have a composition in which the total component ratio of silver (Ag), copper, platinum, and palladium is 80 atom% or more. In the brazing material 130 with this composition, two components separate and undergo a phase change during the solidification process, so as shown in Figure 4, it may contain an Ag-rich portion (corresponding to the first part) B11 with a high silver component ratio and a Cu-rich portion (corresponding to the second part) B12 with a high copper component ratio. The Ag-rich portion B11 may contain 70 atom% or more silver, and the Cu-rich portion B12 may contain 70 atom% or more copper. The Ag-rich portion B11 and the Cu-rich portion B12 may together occupy 90% or more of the area ratio in any cross-section of the brazing material 130. Platinum and palladium may be unevenly distributed within the Cu-rich portion B12. The following shows an example in which the brazing material 130 with this composition is used.

[0095] Furthermore, a low-melting-point brazing material containing gold and tin may be used as the brazing material 130.

[0096] The metal member 110 (see Figure 1) may be a composite or clad material of copper and tungsten, a composite or clad material of copper and molybdenum, or simply copper.

[0097] The conductive layer 163B may be mostly integrated with the brazing material 130. The conductive layer 163B includes an Ag-rich portion B11 and a Cu-rich portion B12, and the Ag-rich portion B11 and the Cu-rich portion B12 may account for 90% or more of the area ratio in any cross-section. In the conductive layer 163B, platinum may be unevenly distributed in the Cu-rich portion B12. Platinum may also be distributed in the Ag-rich portion B11. The concentration of platinum distributed in the Cu-rich portion B12 may be higher than the concentration of platinum distributed in the Ag-rich portion B11. Palladium may be unevenly distributed in the Cu-rich portion B12. Palladium may also be distributed in the Ag-rich portion B11. The concentration of palladium distributed in the Cu-rich portion B12 may be higher than the concentration of palladium distributed in the Ag-rich portion B11. In the conductive layer 163, the copper content may be higher than the platinum content. Furthermore, the copper content may be higher than the palladium content. Also, the copper content may be higher than the combined content of platinum and palladium.

[0098] The intermediate layer 162B may have the same configuration as the first intermediate layer 162a (see Figure 2) described above. During brazing, the second intermediate layer 162b of the intermediate layer 162 of the wiring conductor 16 described above is integrated with the conductive layer 163 and the brazing material 130, while a part of the first intermediate layer 162a remains, and this remaining part of the first intermediate layer 162a may constitute the intermediate layer 162B.

[0099] With the above-described wiring conductor 16B, the composition of the brazing material 130, metallized layer 161, intermediate layer 162B, and conductive layer 163B can reduce or eliminate magnetic metals. Therefore, low magnetism or non-magnetic properties can be achieved for the wiring board 10 and the electronic component housing package 100.

[0100] Furthermore, with the above-described wiring conductor 16B, high adhesion between the metallized layer 161 and the substrate 11 can be easily achieved due to the temperature characteristics of the first metal. In addition, the interposition of the intermediate layer 162B, which contains the components of the metallized layer 161 and the components of the conductive layer 163B, provides high adhesion from the metallized layer 161 to the conductive layer 163B. Thus, high adhesion between the substrate 11 and the wiring conductor 16B can be obtained. Furthermore, due to the components of the conductive layer 163B and the brazing material 130, the conductive layer 163B and the brazing material 130 are integrated, resulting in high bonding strength of the brazing material 130. Thus, high adhesion between the substrate 11 and the wiring conductor 16, as well as high bonding strength between the wiring substrate 10 and the metal member 110, can be achieved.

[0101] Furthermore, with the above-described wiring conductor 16B, a large proportion of copper can be included as a component of the conductive layer 163B. Therefore, the electrical resistance of the conductive layer 163 can be lowered while keeping material costs low.

[0102] Furthermore, with the above-described wiring conductor 16B, a large amount of platinum is distributed in the Cu-rich portion B12 of the conductive layer 163B integrated with the brazing material 130. Therefore, the corrosion resistance of the copper-containing wiring conductor 16B and the brazing material 130 can be improved.

[0103] Furthermore, the palladium contained in the conductive layer 163B suppresses excessive diffusion of platinum into the metallized layer 161. Therefore, the amount of platinum and palladium used can be reduced while increasing the platinum and palladium content in the conductive layer 163. Consequently, the corrosion resistance and heat resistance of the copper-containing conductive layer 163 can be improved.

[0104] <Specific Example 4 of Brazed Wiring Conductor 16B> Next, as Example 4 of Embodiment 2, a specific example of a brazed wiring conductor 16B is shown. In Example 4, tungsten is used for the first metal.

[0105] Figures 11A to 11C and 12A to 12C show the distribution of each component in the wiring conductor 16B of Example 4. Figure 11A is a cross-section of the analysis site, Figure 11B shows the distribution of tungsten (W) at the analysis site, Figure 11C shows the distribution of platinum (Pt) at the analysis site, Figure 12A shows the distribution of palladium (Pd) at the analysis site, Figure 12B shows the distribution of copper (Cu) at the analysis site, and Figure 12C shows the distribution of silver (Ag) at the analysis site. Figure 11A is a simplified SEM image of the analysis site. Figures 11B, 11C, 12B, and 12C are simplified images obtained by mapping the atomic ratio of the corresponding atoms, which are the measurement results of EDS, onto the two-dimensional coordinates of the analysis site. Figure 12A is an image in which the atomic ratio of palladium is estimated based on the EDS measurement results in Example 3 described above. The distribution of palladium in Example 3 is similar to that of platinum.

[0106] In the SEM image in Figure 11A, differences in components appear as differences in contrast. In the images in Figures 11B to 12C, the brightness represents the atomic ratio of the corresponding component. Higher brightness indicates a higher atomic ratio.

[0107] As shown in Figure 11A, in the wiring conductor 16B of Embodiment 4, an intermediate layer 162B with a different composition is located between a metallized layer 161, which is mainly composed of a first metal, and a conductive layer 163B containing copper. As shown in Figure 11A, the intermediate layer 162B may not be located across the entire metallized layer 161, but rather distributed over a portion of the metallized layer 161. In Figure 11A, the intermediate layer 162B, which is divided into multiple parts, is located between the Ag-rich portion B11 and the metallized layer 161, and between the Cu-rich portion B12 and the metallized layer 161, respectively.

[0108] In the conductive layer 163B of Example 4, which is integrated with the brazing material 130, separate Ag-rich portion B11 and Cu-rich portion B12 are located as shown in Figures 11C to 12C. Platinum and palladium are distributed more abundantly in the Cu-rich portion B12 than in the Ag-rich portion B11.

[0109] <Wiring conductor 16 in electrode region 102> The third portion C3 of the wiring board 10 shown in Figure 7 corresponds to the electrode region 102.

[0110] The wiring conductor 16 may have a gold-based adhesive layer 165 above the conductive layer 163 in the electrode region 102. "Gold-based adhesive" means that the gold content is 80 atom% or more. The adhesive layer 165 is a layer intended to bond the electrical bonding member 140. The adhesive layer 165 can improve the bonding performance of the bonding member 140 (see Figure 1).

[0111] The wiring conductor 16 may further have a barrier layer 164 located between the adherend layer 165 and the conductive layer 163. The barrier layer 164 may be mainly composed of platinum, palladium (Pd), or an alloy of platinum and palladium. The barrier layer 164 reduces the thermal diffusion of copper from the conductive layer 163 to the adherend layer 165, thereby maintaining the high adhesive performance of the adherend layer 165. Alternatively, the wiring conductor 16 may not have a barrier layer 164, and the adherend layer 165 may be directly located on the conductive layer 163.

[0112] <Method for Manufacturing a Wired Board> Figure 13 is a flowchart showing an example of a method for manufacturing a wired board 10 according to Embodiment 2. Here, a wired board 10 in which the wiring conductors 16 are located on one surface of the substrate 11 is shown as an example, but the wiring conductors 16 may be located on multiple surfaces of the substrate 11, and the wiring conductors 16 may have various wiring patterns. If a wiring pattern is included, various known patterning processes may be included.

[0113] The manufacturing method for the wiring board 10 may include a firing step J11 for firing the substrate 11 and the metallization layer 161, a coating step J12 for forming a platinum-based coating 181 on the metallization layer 161, a first heating step J13 for allowing the platinum of the coating 181 and the first metal of the metallization layer 161 to permeate each other, a Pd film formation step J14 for forming a palladium first conductive film 183A on the alloy layer 182A formed in the first heating step J13, a Cu film formation step J15 for forming a copper-based second conductive film 184A on the first conductive film 183A, and a second heating step J16 for causing the components to diffuse between the first conductive film 183A, the second conductive film 184A and the alloy layer 182A.

[0114] In the firing process J11, a ceramic green sheet is laminated, and a molded body is formed in which a metallization layer 161 and a metal material serving as an internal wiring conductor are arranged in a desired wiring pattern, and the molded body is fired.

[0115] In the coating process J12, a coating 181 mainly composed of platinum is formed on the metallization layer 161 by plating. Electroplating or electroless plating can be applied for the plating. When applying the electroless plating method, plating may be performed after containing palladium as a trace component as a catalytic active metal.

[0116] The first heating process J13 heats the substrate that has undergone the coating process J12, for example, in a reducing atmosphere 191 such as an N ２ + H ２ atmosphere at, for example, 500°C to 900°C. By this heating, the first metal of the metallization layer 161 diffuses into the coating 181, and an alloy layer 182A of the first metal and platinum is formed.

[0117] In the Pd film formation process J14, a first conductive film 183A mainly composed of palladium is formed on the alloy layer 182A by plating. Electroplating or electroless plating can be applied for the plating. Plating may be performed after containing palladium as a trace component as a catalytic active metal.

[0118] In the Cu film formation process J15, a second conductive film 184A mainly composed of copper is formed on the first conductive film 183A of palladium by plating. Electroplating or electroless plating can be applied for the plating. When applying the electroless plating method, plating may be performed after containing palladium as a trace component as a catalytic active metal.

[0119] The second heating process J16 heats the substrate that has undergone the Pd film formation process J14 and the Cu film formation process J15, for example, in an N ２ + H ２The material is heated in a reducing atmosphere 192, for example, at 400°C to 850°C. This heating causes the platinum in the alloy layer 182A and the palladium in the first conductive film 183A to diffuse into the second conductive film 184A, and the palladium in the first conductive film 183A and the copper in the second conductive film 184A to diffuse into the alloy layer 182A, forming the intermediate layer 162 and the conductive layer 163.

[0120] In the second heating step J16, the palladium in the first conductive film 183A suppresses the amount of copper in the second conductive film 184A that diffuses into the alloy layer 182A. Therefore, relatively speaking, the amount of platinum in the alloy layer 182A and palladium in the first conductive film 183A that diffuses into the second conductive film 184A can be increased. As a result, the intermediate layer 162 formed by the alloy layer 182A enables strong adhesion of the conductive layer 163. Furthermore, by increasing the distribution of platinum and palladium in the conductive layer 163, the corrosion resistance and heat resistance of the copper-containing conductive layer 163 can be improved.

[0121] The wiring board 10 of Embodiment 2 can be manufactured using the manufacturing method described above. Note that the above manufacturing method is just one example, and the wiring board 10 can be manufactured by changing several factors, such as the components of each layer and film, the parameters of each process, and the process procedure.

[0122] (Embodiment 3) The electronic component housing package 100 of Embodiment 3 may be the same as that of Embodiment 2, except that the distribution of platinum and palladium in some areas is different. Next, a configuration different from that of Embodiment 2 will be described. The electronic component housing package 100 of Embodiment 3 has the same structure as that described in Figures 1, 2, and 7.

[0123] In Embodiment 3, the term "main component" means a content of 80 atom% or more. When multiple components are referred to as "main components," it means that the total content of the multiple components is 80 atom% or more.

[0124] <Wiring Conductor 16> Figure 2 is an enlarged cross-sectional view showing the first portion C1 of the wiring board 10 in Figure 1. As shown in Figure 2, the wiring conductor 16 located in the first portion C1 of Embodiment 3 includes a metallized layer 161 located on the surface of the substrate 11 and fired simultaneously with the substrate 11, an intermediate layer 162 located on the metallized layer 161, and a conductive layer 163 containing copper (Cu) located on the intermediate layer 162. In the above, the conductive layer 163 is considered to be above the substrate 11.

[0125] The wiring conductor 16 may be the same as the wiring conductor 16 of Embodiment 2, except for the distribution of platinum and palladium in the conductive layer 163. The metallized layer 161 mainly consists of a first metal composed of at least one of tungsten (W), molybdenum (Mo), and manganese (Mn). The intermediate layer 162 mainly consists of an alloy composed of the first metal, platinum, and palladium. The conductive layer 163 mainly consists of copper, platinum, and palladium. The same effects and advantages as in Embodiment 2 can be obtained with a similar configuration.

[0126] In Embodiment 3, the distribution of platinum and palladium in the conductive layer 163 may vary. That is, platinum and palladium may be unevenly distributed in the conductive layer 163. Furthermore, palladium may be more abundant in areas with a low distribution of platinum, and less abundant in areas with a high distribution of platinum. In other words, the conductive layer 163 includes a first region where platinum is distributed and a second region where the distribution of platinum is less than in the first region, and palladium may be more abundant in the second region than in the first region. The difference in distribution between Embodiment 2 and the 3th diameter plate is due to the difference in the manufacturing method, which will be described later.

[0127] Figures 14A to 15B and 16A to 17B show diagrams analyzing the distribution of each component of the wiring conductor 16 of Embodiment 3. Figures 14A and 16A show a cross-section of the analysis area, Figures 14B and 16B show the distribution of tungsten (W) at the analysis area, Figures 15A and 17A show the distribution of platinum (Pt) at the analysis area, and Figures 15B and 17B show the distribution of palladium (Pd) at the analysis area. Figures 14A and 16A are simplified SEM (Scanning Electron Microscope) images of the analysis area. Figures 14B to 15B and 16B to 17B are simplified images obtained by mapping the atomic ratio of the relevant atoms, which is the measurement result of EDS (Energy Dispersive X-ray Spectroscopy), to the two-dimensional coordinates of the analysis area. In Figures 14B to 15B and 16B to 17B, the brighter the area, the greater the number of corresponding atoms.

[0128] Figures 14A to 15B show the configuration before the first heating step J24 and the Cu film deposition step J25, which will be described later. Figures 16A to 17B show the configuration after the first heating step J24 and before the Cu film deposition step J25. In Embodiment 3, platinum and palladium diffuse simultaneously in the first heating step J24. As can be seen from a comparison between Figures 14A, 15A, and 15B and Figures 16A, 17A, and 17B, it is shown that a platinum-uneven distribution area (corresponding to the first region) K1 and a palladium-uneven distribution area (corresponding to the second region) K2 are formed in the first layer 163a. ​​The first layer 163a is a layer in which copper is distributed by copper film deposition and subsequent heat treatment. As shown in Figures 16A to 17B, the Cu film deposition process J25 and the second heating process J26 are performed, and the distribution of platinum and palladium in the first layer 163a appears in the conductive layer 163.

[0129] Even if platinum is unevenly distributed in the first layer 163a, the distribution of palladium in areas with less platinum distribution allows for stronger adhesion of the conductive layer 163 formed on the first layer 163a.

[0130] <Wiring conductor 16 in electrode region 102> The third region C3 of the wiring substrate 10 shown in Figure 7 corresponds to the region including the electrode region 102. The wiring conductor 16 located in the third region C3 of Embodiment 3 has a metallized layer 161 located on the surface of the substrate 11 and fired at the same time as the substrate 11, an intermediate layer 162 located on the metallized layer 161, a conductive layer 163 containing copper (Cu) located on the intermediate layer 162, and a deposit layer 165 mainly composed of gold located above the conductive layer 163. A barrier layer 164 may be provided between the conductive layer 163 and the deposit layer 165.

[0131] The metallizing layer 161, intermediate layer 162, and conductive layer 163 are the same as those of the first part C1 in Embodiment 2. The barrier layer 164 and adherend layer 165 are the same as those of the barrier layer 164 and adherend layer 165 in Embodiment 2. With the same configuration as in Embodiment 2, the same effects and advantages as in Embodiment 2 can be obtained.

[0132] Furthermore, with respect to the wiring conductor 16 of the third part C3, a conductive layer 163 having regions in which platinum and palladium are unevenly distributed can be achieved, thereby enabling stronger adhesion of the conductive layer 163.

[0133] <Brazed Wiring Conductor 16B> Figure 18 is an enlarged cross-sectional view showing the second portion C2 of the wiring board 10 of Embodiment 3. The second portion C2 corresponds to the area where the metal member 110 is joined to the wiring conductor 16B via the brazing material 130, as shown in Figure 1.

[0134] In Embodiment 3, the wiring conductor 16B brazed to the metal member 110 may include a metallized layer 161 located on the surface of the substrate 11 and an intermediate layer 162B located on the metallized layer 161, as shown in Figure 18. A brazing material 130 integrated with a part of the wiring conductor 16B is located on the intermediate layer 162B, and the metal member 110 is in close contact with another end face of the brazing material 130.

[0135] The metallized layer 161 is mainly composed of a first metal consisting of at least one of tungsten (W), molybdenum (Mo), and manganese (Mn). The intermediate layer 162B is mainly composed of an alloy consisting of the first metal, platinum (Pt), and palladium (Pd). The brazing material 130 is mainly composed of silver (Ag), copper (Cu), platinum (Pt), and palladium (Pd). The metal member 110 is pure copper (Cu), a composite or clad material of copper (Cu) and tungsten (W), or a composite or clad material of copper (Cu) and molybdenum (Mo).

[0136] In the brazing material 130 of Embodiment 3, the two components separate and undergo a phase change during the solidification process, resulting in the inclusion of an Ag-rich portion (corresponding to the first portion) B11 with a high silver content and a Cu-rich portion (corresponding to the second portion) B12 with a high copper content. In other words, copper and silver may be exclusively distributed. Furthermore, platinum may be predominantly distributed in the Ag-rich portion B11, and palladium may be predominantly distributed in the Cu-rich portion B12.

[0137] The metallized layer 161 and the intermediate layer 162B may be the same as those in Embodiment 2. With the same configuration as in Embodiment 2, the same effects and advantages as in Embodiment 2 can be obtained.

[0138] Figures 19A to 20C show the analysis of the distribution of each component in the wiring conductor 16B and brazing material 130 of the second section C2. Figure 19A is a cross-section of the analysis area, Figure 19B shows the distribution of silver (Ag) in the analysis area, Figure 19C shows the distribution of copper (Cu) in the analysis area, Figure 20A shows the distribution of palladium (Pd) in the analysis area, Figure 20B shows the distribution of platinum (Pt) in the analysis area, and Figure 20C shows the distribution of tungsten (W) in the analysis area. Figure 19A is a simplified SEM (Scanning Electron Microscope) image of the analysis area. Figures 19B to 20C are simplified images obtained by mapping the atomic ratio of the corresponding atoms, which is the measurement result of EDS (Energy Dispersive X-ray Spectroscopy), onto the two-dimensional coordinates of the analysis area. In Figures 19B to 20C, brighter areas indicate a higher concentration of the corresponding atoms.

[0139] As shown in Figures 19B and 19C, the brazing material 130 is mainly composed of an Ag-rich portion B11 and a Cu-rich portion B12. As shown in Figures 20A and 20B, platinum and palladium are unevenly distributed in the brazing material 130. Platinum is more abundant in the Cu-rich portion B12, and palladium is more abundant in the Ag-rich portion B11.

[0140] With the above-described wiring conductor 16B, the composition of the brazing material 130, the metallized layer 161, and the intermediate layer 162B can reduce or eliminate the amount of magnetic metal. Therefore, low magnetism or non-magnetic properties can be achieved for the wiring board 10 and the electronic component housing package 100.

[0141] Furthermore, with the above-described wiring conductor 16B, high adhesion between the metallized layer 161 and the substrate 11 can be easily achieved due to the temperature characteristics of the first metal. Moreover, the interposition of the intermediate layer 162B, which contains the components of the metallized layer 161 and the components of the brazing material 130, provides high adhesion from the metallized layer 161 to the brazing material 130. Therefore, high bonding strength of the brazing material 130 to the wiring conductor 16B can be achieved, and consequently, high bonding strength between the wiring substrate 10 and the metal member 110 can be achieved.

[0142] Furthermore, with the above-described wiring conductor 16B, a large proportion of copper can be included as a component of the brazing material 130. Therefore, the electrical resistance of the brazing material 130 can be lowered while keeping material costs low.

[0143] Furthermore, with the above-described wiring conductor 16B, a large amount of platinum is distributed in the Cu-rich portion B12 of the brazing material 130. Therefore, the corrosion resistance of the copper-containing brazing material 130 can be improved.

[0144] <Method for Manufacturing a Wired Board> Figure 21 is a flowchart showing an example of a method for manufacturing a wired board 10 according to Embodiment 3. Here, a wired board 10 in which the wiring conductors 16 are located on one surface of the substrate 11 is shown as an example, but the wiring conductors 16 may be located on multiple surfaces of the substrate 11, and the wiring conductors 16 may have various wiring patterns. If wiring patterns are included, various known patterning processes may be included.

[0145] The manufacturing method for the wiring board 10 in Embodiment 3 may include a firing step J21 for firing the substrate 11 and the metallization layer 161, a Pt film deposition step J22 for forming a first platinum conductive film 201 on the metallization layer 161, a Pd film deposition step J23 for forming a second palladium conductive film 202 on the first conductive film 201, a first heating step J24 for impregnating the first metal of the metallization layer 161 with platinum and palladium from the first conductive film 201 and the second conductive film 202, a Cu film deposition step J25 for forming a third conductive film 205 mainly composed of copper on the alloy layer 204 formed in the first heating step J24, and a second heating step J26 for impregnating the components of the third conductive film 205 and the alloy layer 204 with each other.

[0146] In firing process J21, ceramic green sheets are laminated, and a molded body is formed in which the metallized layer 161 and the metal material that will become the internal wiring conductor are arranged in a desired wiring pattern, and the molded body is fired.

[0147] In the Pt film formation process J22, a first conductive film 201 mainly composed of platinum is formed on the metallized layer 161 by plating. The plating can be performed using either electrolytic plating or electroless plating.

[0148] In the Pd film formation step J23, a second conductive film 202, mainly composed of palladium, is formed on the first conductive film 201 by plating. The plating can be performed using either electrolytic plating or electroless plating.

[0149] The first heating step J24 involves heating the substrate that has gone through the Pt film deposition step J22 and the Pd film deposition step J23, for example, N ２ +H ２ The material is heated in a reducing atmosphere 211, for example, at 500°C to 950°C. This heating causes the platinum and palladium from the first conductive film 201 and the second conductive film 202 to diffuse into the first metal of the metallized layer 161, forming an alloy layer 204 mainly composed of the first metal, platinum, and palladium.

[0150] In the Cu film formation process J25, a third conductive film 205, mainly composed of copper, is formed on the alloy layer 204 by plating. The plating can be performed using either electrolytic plating or electroless plating.

[0151] In the second heating step J26, the substrate that has gone through the Pd film deposition step J23 and the Cu film deposition step J25 is heated, for example, N ２ +H ２ The material is heated in a reducing atmosphere 212, for example, at 400°C to 850°C. During this heating, when copper diffuses into the alloy layer 204, which is mainly composed of the first metal, platinum, and palladium, the amount of copper diffusion is suppressed by the palladium. This suppression relatively increases the amount of platinum and palladium that diffuse into the copper in the third conductive film 205. As a result, the intermediate layer 162 and the conductive layer 163 are formed, and a strong connection is achieved between the metallized layer 161 and the conductive layer 163. Furthermore, the diffusion of platinum into the copper of the conductive layer 163 improves the corrosion resistance and heat resistance of the conductive layer 163.

[0152] The wiring board 10 of Embodiment 3 can be manufactured using the manufacturing method described above. Note that the above manufacturing method is just one example, and the wiring board 10 can be manufactured by changing several factors, such as the components of each layer and film, the parameters of each process, and the process procedure.

[0153] Embodiments 1 to 3 of this disclosure have been described above. However, the present invention is not limited to the above embodiments. Details shown in the embodiments can be modified as appropriate without departing from the spirit of the invention.

[0154] An embodiment of the present disclosure is shown below. In one embodiment, (1) the wiring board comprises a ceramic substrate, a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese and located on the substrate, an intermediate layer containing the first metal, copper, platinum, and palladium and located on the metallized layer, and a conductive layer containing copper, platinum, and palladium and located on the intermediate layer.

[0155] (2) The wiring board in (1) above has a conductive layer in which the total content of copper, platinum and palladium is 80 atom% or more.

[0156] (3) The wiring board described in (1) or (2) above has an intermediate layer in which the content of the alloy of the first metal, platinum, and palladium is 80 atom% or more.

[0157] (4) Any one of the wiring boards described in (1) to (3) above has a non-symmetric distribution of platinum and palladium in the conductive layer, the conductive layer includes a first region in which platinum is distributed and a second region in which the distribution of platinum is less than that of the first region, and palladium is more abundant in the second region than in the first region.

[0158] (5) Any one of the wiring boards described in (1) to (4) above, wherein the intermediate layer includes a first intermediate layer that is closer to the metallized layer than the conductive layer, and a second intermediate layer that is closer to the conductive layer than the first intermediate layer, wherein the copper, platinum, and palladium content in the second intermediate layer is higher than the copper, platinum, and palladium content in the first intermediate layer, and the first metal content in the first intermediate layer is higher than the first metal content in the second intermediate layer.

[0159] (6) Any one of the wiring boards described in (1) to (5) above has a conductive layer in which the total content of copper, platinum and palladium is 80 atom% or more, and the copper content is higher than the total content of platinum and palladium.

[0160] (7) Any one of the wiring boards described in (1) to (6) above further comprises a non-magnetic metal member bonded to the conductive layer via a brazing material.

[0161] (8) The wiring board in (7) above, wherein the metal member is a composite or clad material of copper and tungsten, a composite or clad material of copper and molybdenum, or copper.

[0162] (9) The wiring board in (7) or (8) above has a brazing material in which the total content of silver, copper, platinum and palladium is 80 atom% or more.

[0163] (10) Any one of the wiring boards described in (7) to (9) above, wherein the brazing material comprises a first part having a higher silver content than copper and a second part having a higher copper content than silver, and platinum and palladium are predominantly located in the second part.

[0164] (11) Any one of the wiring boards described in (7) to (9) above, wherein the brazing material comprises a first part having a higher silver content than copper and a second part having a higher copper content than silver, with palladium unevenly distributed in the first part and platinum unevenly distributed in the second part. (12) Any one of the wiring boards described in (1) to (11) above, wherein the conductive layer has an electrode portion in at least a part of its planar view to which the electrodes of an element are connected via a connecting member, and further comprises a adherend layer whose main component is gold and which is located at least above the electrode portion of the conductive layer.

[0165] (13) The wiring board described in (12) above is mainly composed of platinum, palladium, or an alloy of platinum and palladium, and further comprises a barrier layer located between the conductive layer and the adherend layer.

[0166] In one embodiment, (14) the electronic component housing package comprises a wiring board as described in any one of (1) to (13) above.

[0167] In one embodiment, (15) a method for manufacturing a wiring board comprises firing a ceramic substrate and a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese and located on the substrate; forming a metal film mainly composed of platinum on the metallized layer; heating the substrate on which the metal film is formed in a reducing atmosphere to form an alloy layer containing the first metal and platinum on the metallized layer; forming a first conductive film mainly composed of palladium on the alloy layer; forming a second conductive film mainly composed of copper on the first conductive film; and heating the substrate on which the first conductive film and the second conductive film are formed in a reducing atmosphere to diffuse the platinum in the alloy layer and the palladium in the first conductive film into the second conductive film.

[0168] In one embodiment, (16) a method for manufacturing a wiring board comprises firing a ceramic substrate and a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese and located on the substrate; forming a first conductive film mainly composed of platinum on the metallized layer; forming a second conductive film mainly composed of palladium on the first conductive film; heating the substrate on which the first and second conductive films are formed in a reducing atmosphere to form a layer of alloy containing the first metal, platinum, and palladium on the metallized layer; forming a third conductive film mainly composed of copper on the alloy layer; and heating the substrate on which the alloy layer and the third conductive film are formed in a reducing atmosphere to diffuse the platinum and palladium from the alloy layer into the third conductive film.

[0169] In one embodiment, (17) the brazing material is a brazing material that joins a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese to a composite or clad material of copper and tungsten, a composite or clad material of copper and molybdenum, or a metal member that is copper, wherein the total content of silver, copper, platinum, and palladium is 80 atom% or more, and it comprises a first part in which the silver content is higher than that of copper, and a second part in which the copper content is higher than that of silver, with palladium unevenly distributed in the first part and platinum unevenly distributed in the second part.

[0170] In one embodiment, (18) the wiring board comprises a ceramic substrate, a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese and located on the substrate, an intermediate layer containing the first metal, copper, and platinum and located on the metallized layer, and a conductive layer containing copper and platinum and located on the intermediate layer.

[0171] In one embodiment, (19) a method for manufacturing a wiring board comprises firing a ceramic substrate and a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese and located on the substrate; forming a metal film mainly composed of platinum on the metallized layer; forming an alloy layer containing the first metal and platinum on the metallized layer by heating the substrate on which the metal film is formed in a reducing atmosphere; forming a conductive film mainly composed of copper on the alloy layer; and diffusing the platinum from the alloy layer into the conductive film by heating the substrate on which the conductive film is formed in a reducing atmosphere.

[0172] This disclosure can be used for wiring boards, electronic component housing packages, brazing materials, and methods for manufacturing wiring boards.

[0173] 10 Wiring board 11 Substrate 16, 16B Wiring conductor 100 Package for housing electronic components 101 Mounting area 102 Electrode area 110 Metal component 130 Brazing material 161 Metallized layer 162, 162B Intermediate layer 162a First intermediate layer 162b Second intermediate layer 163, 163B Conductive layer 164 Barrier layer 165 Adhered layer 162B Intermediate layer 163B Conductive layer 181 Coating 182 Alloy layer 182A Alloy layer 183 Conductive film 183A First conductive film 184A Second conductive film 191, 192 Reducing atmosphere 201 First conductive film 202 Second conductive film 204 Alloy layer 205 Third conductive film 211, 212 Reducing atmosphere 300 Electronic Components B11 Ag-rich section (Part 1) B12 Cu-rich section (Part 2)

Claims

A ceramic substrate, A metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese, and located on the substrate, An intermediate layer located on the metallized layer, comprising the first metal, copper, platinum, and palladium, A conductive layer containing copper, platinum, and palladium, located on the intermediate layer, A wiring board equipped with the following features. 　 The conductive layer has a total content of 80 atoms or more of copper, platinum, and palladium. A wiring board according to claim 1. 　 The intermediate layer has an alloy content of the first metal, platinum, and palladium of 80 atom percent or more. A wiring board according to claim 1. 　 Platinum and palladium are unevenly distributed in the aforementioned conductive layer. The conductive layer includes a first region where platinum is distributed and a second region where the distribution of platinum is less than in the first region, and palladium is more abundant in the second region than in the first region. A wiring board according to claim 1. 　 The intermediate layer includes a first intermediate layer that is closer to the metallized layer than the conductive layer, and a second intermediate layer that is closer to the conductive layer than the first intermediate layer. The copper, platinum, and palladium content in the second intermediate layer is higher than the copper, platinum, and palladium content in the first intermediate layer, The content of the first metal in the first intermediate layer is higher than the content of the first metal in the second intermediate layer. A wiring board according to claim 1. 　 The conductive layer has a total content of 80 atoms or more of copper, platinum, and palladium, and the copper content is higher than the total content of platinum and palladium. A wiring board according to claim 1. 　 The conductive layer further comprises a non-magnetic metal member bonded to it via a brazing material. A wiring board according to claim 1. 　 The aforementioned metal member is a composite or clad material of copper and tungsten, a composite or clad material of copper and molybdenum, or copper. The wiring board according to claim 7. 　 The brazing material has a total content of 80 atoms or more of silver, copper, platinum, and palladium. The wiring board according to claim 7. 　 The aforementioned brazing material comprises a first part having a higher silver content than copper, and a second part having a higher copper content than silver. Platinum and palladium are predominantly found in the second part. The wiring board according to claim 9. 　 The aforementioned brazing material comprises a first part having a higher silver content than copper, and a second part having a higher copper content than silver. Palladium is unevenly distributed in the first part, and platinum is unevenly distributed in the second part. The wiring board according to claim 9. 　 The conductive layer has, in a plan view, at least a portion of which the electrodes of the element are connected via a connecting member, an electrode portion. The device further comprises a deposition layer whose main component is gold and which is located at least above the electrode portion of the conductive layer. A wiring board according to claim 1. The main component is platinum, palladium, or an alloy of platinum and palladium, and the device further comprises a barrier layer located between the conductive layer and the adherend layer. The wiring board according to claim 12. 　 An electronic component housing package comprising a wiring board according to any one of claims 1 to 13. 　 A ceramic substrate and a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese and located on the substrate are fired together. A metal film mainly composed of platinum is formed on the metallized layer. By heating the substrate on which the metal film is formed in a reducing atmosphere, a layer of alloy containing the first metal and platinum is formed on the metallized layer. A first conductive film mainly composed of palladium is formed on the alloy layer. A second conductive film mainly composed of copper is formed on the first conductive film. The substrate on which the first conductive film and the second conductive film are formed is heated in a reducing atmosphere to diffuse the platinum in the alloy layer and the palladium in the first conductive film into the second conductive film. A method for manufacturing a wiring board. 　 A ceramic substrate and a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese and located on the substrate are fired together. A first conductive film mainly composed of platinum is formed on the metallized layer. A second conductive film mainly composed of palladium is formed on the first conductive film. By heating the substrate on which the first conductive film and the second conductive film are formed in a reducing atmosphere, a layer of alloy containing the first metal, platinum, and palladium is formed on the metallized layer. A third conductive film mainly composed of copper is formed on the alloy layer. The substrate on which the alloy layer and the third conductive film are formed is heated in a reducing atmosphere to diffuse the platinum and palladium in the alloy layer into the third conductive film. A method for manufacturing a wiring board. 　 A brazing material that joins a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese to a composite or clad material of copper and tungsten, a composite or clad material of copper and molybdenum, or a metal member that is copper, The total content of silver, copper, platinum, and palladium is 80 atoms or more. It contains two parts: Part 1, which has a higher silver content than copper, and Part 2, which has a higher copper content than silver. Palladium is unevenly distributed in the first part, and platinum is unevenly distributed in the second part. Brazing material. A ceramic substrate, A metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese, and located on the substrate, An intermediate layer located on the metallized layer, comprising the first metal, copper, and platinum, A conductive layer containing copper and platinum, located on the intermediate layer, A wiring board equipped with the following features. 　 A ceramic substrate and a metallized layer having a first metal consisting of at least one of tungsten, molybdenum, and manganese and located on the substrate are fired together. A metal film mainly composed of platinum is formed on the metallized layer. By heating the substrate on which the metal film is formed in a reducing atmosphere, a layer of alloy containing the first metal and platinum is formed on the metallized layer. A conductive film mainly composed of copper is formed on the alloy layer. The substrate on which the conductive film is formed is heated in a reducing atmosphere to diffuse the platinum in the alloy layer into the conductive film. A method for manufacturing a wiring board.

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