Wiring board and method for manufacturing the same

Abstract

To provide a wiring board having such a structure that the surface of a resistor is covered with a resin layer, which improves accuracy of a resistance value of the resistor.SOLUTION: A wiring board includes a ceramic substrate, a thin film resistor arranged on the ceramic substrate, a first resin layer which is formed of a resin and is arranged in a part where the resistor is not arranged on the ceramic substrate, and a second resin layer which is formed of a resin and covers the resistor on the ceramic substrate.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a wiring board and a method for manufacturing a wiring board. [Background technology]

[0002] A wiring board having a thin-film resistor whose resistance value is adjusted by trimming is known. For example, see Patent Document 1. In the wiring board described in Patent Document 1, A resistor is formed on the surface, and the resistor is covered with a resin substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-064999 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to make the resistance value of the resistor more accurate, it is necessary to perform laser trimming on the resistor. After the resistance value of the resistor is adjusted by trimming, if a resin layer is placed on the resistor and the ceramic substrate, and heat and pressure are applied to bond the resin layer and the ceramic substrate, the resistance value of the resistor will fluctuate. On the other hand, if the resin layer is formed before trimming the resistor and laser trimming is performed on the resin layer, it is difficult to adjust the resistance value because the resistor cannot be directly seen.

[0005] The present invention has been made to solve at least part of the above-mentioned problems, and aims to improve the accuracy of the resistance value of a resistor in a wiring board in which the surface of a resistor is covered with a resin layer. [Means for solving the problem]

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms. A wiring board comprising: a ceramic substrate, a thin-film resistor disposed on the ceramic substrate, a first resin layer formed of resin and disposed on a portion of the ceramic substrate where the resistor is not disposed, and a second resin layer formed of resin and covering the resistor on the ceramic substrate, the first resin layer having a through hole penetrating a first surface facing the ceramic substrate and a second surface positioned opposite to the first surface, the second resin layer being filled in the through hole of the first resin layer and consisting of a plurality of layers, the resistor being disposed on the ceramic substrate, inside the through hole of the first resin layer and between the plurality of layers constituting the second resin layer.

[0007] (1) According to one aspect of the present invention, there is provided a wiring board comprising: a ceramic substrate, a thin-film resistor disposed on the ceramic substrate, a first resin layer formed of resin and disposed on a portion of the ceramic substrate where the resistor is not disposed, and a second resin layer formed of resin and covering the resistor on the ceramic substrate.

[0008] According to this configuration, there are two resin layers on the ceramic substrate, a first resin layer arranged in a portion where the resistor is not arranged, and a second resin layer covering the resistor. With this configuration, after applying heat and pressure to the first resin layer to bond the first resin layer to the ceramic substrate, the resistance value of the resistor can be adjusted and the second resin layer can be formed to cover the resistor. Since heating and pressure can be applied to bond the first resin layer to the ceramic substrate before the resistance value of the resistor is adjusted, the temperature of heat applied when forming the second resin layer can be made smaller than that when bonding the first resin layer to the ceramic substrate. Furthermore, the number of heating cycles and heating time applied when forming the second resin layer can be made smaller than that when bonding the first resin layer to the ceramic substrate. That is, the thermal fluctuation applied to the resistor when forming the second resin layer can be made smaller than that when bonding the first resin layer to the ceramic substrate. That is, the thermal fluctuation applied to the resistor can be suppressed, so that the resistance value of the resistor can be adjusted with high precision. Furthermore, since the resistor is covered by the second resin layer, the resistor can be protected from the effects of chemicals, oxidation, and the like. As a result, in a wiring board in which the surface of a resistor is covered with a resin layer (second resin layer), the precision of the resistance value of the resistor can be improved.

[0009] (2) In the wiring board of the above embodiment, the first resin layer may have a through hole penetrating a first surface facing the ceramic substrate and a second surface located opposite the first surface, the resistor is disposed inside the through hole of the first resin layer on the ceramic substrate, and the second resin layer may be filled inside the through hole of the first resin layer. According to this configuration, on the ceramic substrate, the first resin layer has a shape surrounding the resistor placed in the through hole. With this configuration, the first resin layer and the ceramic substrate are joined in a state where a resistor whose resistance value is not adjusted is placed on the ceramic substrate, and then the resistance value of the resistor is adjusted and the second resin layer is filled in to form a wiring substrate. This makes it possible to easily form a wiring substrate having a configuration in which the surface of the resistor is covered with a resin layer (second resin layer).

[0010] (3) In the wiring board of the above aspect, the second resin layer may be made up of a plurality of layers, and the resistor may be disposed between the plurality of layers constituting the second resin layer. According to this configuration, the thickness of each of the multiple layers constituting the second resin layer is adjusted, whereby the position in the thickness direction at which the resistor is disposed is adjusted.

[0011] (4) According to another aspect of the present invention, there is provided a method for manufacturing a wiring board, comprising the steps of: arranging a thin-film resistor on a ceramic substrate; bonding a resin sheet having a through hole penetrating in a thickness direction, onto the ceramic substrate such that the resistor is disposed inside the through hole; adjusting a resistance value of the resistor by laser trimming; and filling the through hole with a liquid resin. According to this configuration, in the bonding process, the resin sheet is bonded onto the ceramic substrate so that the resistors arranged on the ceramic substrate are arranged inside the through-holes of the resin sheet. After that, the resistance value of the resistors arranged inside the through-holes is adjusted by laser trimming, and the through-holes are filled with liquid resin. As a result, it is possible to suppress the heat and pressure applied to the resistors when bonding the resin sheet onto the ceramic substrate. In addition, the temperature of heat applied to the liquid resin to form a resin layer and the number of times heat is applied are suppressed compared to when the resin sheet is bonded. As a result, the thermal fluctuation applied to the resistors whose resistance values ​​have been adjusted is suppressed, and in this configuration, the surface of the resistors is covered with resin, and the resistance value of the resistors can be maintained in a state where it has been adjusted with high precision.

[0012] The present invention can be realized in various forms, for example, in the form of a wiring board, a semiconductor device, an electronic component, a system including these, a method for manufacturing a wiring board, and a system including these. [Brief description of the drawings]

[0013] [Figure 1] 1 is an explanatory diagram of a wiring board according to an embodiment of the present invention; [Diagram 2] 1 is an explanatory diagram of a wiring board according to an embodiment of the present invention; [Diagram 3] 4 is a flowchart of a method for manufacturing a wiring board according to the present embodiment. [Figure 4] FIG. 2 is a schematic front view of a resin sheet having through holes formed therein; [Diagram 5] FIG. 4 is a schematic front view of the ceramic substrate during a placement process. [Figure 6] 4 is a schematic front view of the ceramic substrate and the resin sheet during a bonding process. FIG. [Figure 7] 10 is a schematic front view of the ceramic substrate and the resin sheet after an adjustment process. FIG. [Figure 8] 4 is a schematic front view of the ceramic substrate and the resin sheet after a filling step. FIG. [Figure 9] FIG. 11 is a schematic plan view of a wiring board of a comparative example. [Figure 10] 11 is a flowchart of a method for manufacturing a wiring board according to a comparative example. [Figure 11] FIG. 11 is a schematic cross-sectional view of a wiring board according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] <Embodiment> 1 and 2 are explanatory diagrams of a wiring board 100 according to an embodiment of the present invention. FIG. 1 shows a schematic front view of the wiring board 100. FIG. 2 shows a schematic view of the wiring board 100 taken along the line AA in FIG. 1. In this embodiment, a resistor 40 is disposed on a ceramic substrate 10. A resin sheet 20 having a through hole HL penetrating the resin sheet 20 in the thickness direction is bonded to the ceramic substrate 10 such that the resistor 40 is disposed inside the through hole HL. After bonding, the resistance value of the resistor 40 is adjusted by laser trimming. Then, the through hole HL is filled with a liquid resin, and the liquid resin is cured.

[0015] 1 and 2, the wiring board 100 includes a ceramic substrate 10 whose main component is ceramic, a thin-film resistor 40 disposed on the ceramic substrate 10, a resin sheet (first resin layer) 20 disposed on the ceramic substrate 10, and a resin coat (second resin layer) 30 covering the resistor 40 on the ceramic substrate 10. The wiring board 100 of this embodiment is a substrate including at least one resistor 40. In this embodiment, the term "main component" refers to a component that accounts for 90% by mass or more.

[0016] The ceramic substrate 10 has a rectangular shape with a predetermined thickness. In this embodiment, an axis parallel to the thickness direction of the ceramic substrate 10 is defined as the Z-axis, and an orthogonal coordinate system CS in which X-axis and Y-axis are defined as being perpendicular to the Z-axis and parallel to each side of the ceramic substrate 10 are shown in Figures 1 and 2. The orthogonal coordinate system CS corresponds to the orthogonal coordinate system CS shown in Figure 4 and subsequent figures.

[0017] 2, the resin sheet 20 has a through hole HL penetrating a first surface 20A on the Z-axis negative side facing the ceramic substrate 10 and a second surface 20B on the Z-axis positive side opposite the first surface 20A. As shown in FIG 1, the through hole HL in this embodiment is a rectangular hole having a side parallel to the X-axis and a side parallel to the Y-axis.

[0018] The resin sheet 20 of this embodiment includes a first sheet 21, a second sheet 22, and a third sheet 23, each of which is made of a resin. As shown in FIG. 2, the first sheet 21, the second sheet 22, and the third sheet 23 are laminated in this order from the ceramic substrate 10 side. Each of the sheets 21 to 23 is preferably made mainly of a resin that does not melt when a metal member is brazed to the wiring substrate 100 (that is, has a melting point higher than that of the brazing material or solder). As such a resin, polyimide, which also has excellent chemical resistance, is preferable. The resin sheet 20 is joined to the ceramic substrate 10 by fusion of a heat-sealing layer (not shown) provided on the first surface 20A.

[0019] 2, in this embodiment, wiring layers having predetermined wiring patterns are disposed between the ceramic substrate 10 and the first sheet 21, between the first sheet 21 and the second sheet 22, and between the second sheet 22 and the third sheet 23. Examples of materials for forming the wiring layers include W, Mo, Mn, Cu, Ag, and alloys thereof.

[0020] The resistor 40 is disposed on the ceramic substrate 10 inside the through hole HL of the resin sheet 20 as shown in Figs. 1 and 2. In other words, the resin sheet 20 is disposed on the ceramic substrate 10 in a portion where the resistor 40 is not disposed. The resistor 40 is formed to a certain size, and then its planar shape (i.e., area) is adjusted by laser trimming so as to have a desired resistance value. The thickness of the resistor 40 is on the order of several thousand angstroms. For example, TaN (tantalum nitride) can be suitably used as the material for the resistor 40.

[0021] 2, the resin coat 30 is arranged so as to fill the inside of the through holes HL of the resin sheet 20. The resin coat 30 of this embodiment is formed by hardening a liquid resin filled in the through holes HL after the resin sheet 20 is bonded to the ceramic substrate 10. As a result, the resin coat 30 is arranged so as to cover the resistor 40 on the ceramic substrate 10. In this embodiment, the resin coat 30 is formed of polyimide, but may be formed of other well-known resins.

[0022] Fig. 3 is a flowchart of a method for manufacturing the wiring board 100 of this embodiment. In the manufacturing flow shown in Fig. 3, first, a resin sheet 20 is prepared by laminating three sheets, a first sheet 21, a second sheet 22, and a third sheet 23 (step S1). A wiring layer is disposed between each of the sheets 21 to 23. Next, a through hole HL is formed in the prepared resin sheet 20 in the thickness direction (step S2). Fig. 4 is a schematic front view of the resin sheet 20 in which the through hole HL is formed. As shown in Fig. 4, in this embodiment, a rectangular through hole HL is formed in the center of the resin sheet 20.

[0023] Once the through holes HL are formed in the resin sheet 20, a placement step is performed in which the resistor 40 is placed on the prepared ceramic substrate 10 (step S3 in FIG. 3). The ceramic substrate 10 on which the resistor 40 is placed is an unfired ceramic green sheet. FIG. 5 is a schematic front view of the ceramic substrate 10 during the placement step. As shown in FIG. 5, in this embodiment, the resistor 40 is placed at the center of the surface of the ceramic substrate 10 on the positive side of the Z axis.

[0024] After the arrangement step, a joining step is performed in which the resin sheet 20 is joined onto the ceramic substrate 10 (step S4 in FIG. 3). FIG. 6 is a schematic front view of the ceramic substrate 10 and the resin sheet 20 during the joining step. As shown in FIG. 6, in the joining step, the resin sheet 20 is joined to the ceramic substrate 10 such that the resistor 40 is placed inside the through-hole HL of the resin sheet 20. After the resin sheet 20 is placed so that the first surface 20A faces the ceramic substrate 10, the resin sheet 20 is heated and pressurized to fuse the thermally adhesive layer, thereby joining the resin sheet 20 to the ceramic substrate 10.

[0025] After the bonding step, an adjustment step is performed to adjust the resistance value of resistor 40 by laser trimming (step S5 in FIG. 3). FIG. 7 is a schematic front view of ceramic substrate 10 and resin sheet 20 after the adjustment step. In this embodiment, notches 42 are formed in body portion 41 of resistor 40 by laser trimming, thereby adjusting the area of ​​resistor 40. This adjusts the resistance value of resistor 40.

[0026] After the adjusting step, a filling step is performed in which liquid resin is filled into the through holes HL (step S6 in FIG. 3). FIG. 8 is a schematic front view of the ceramic substrate 10 and the resin sheet 20 after the filling step. In FIG. 8, the liquid resin filled in the through holes HL is shown hatched. The liquid resin is filled into the through holes HL until it reaches the same thickness as the resin sheet 20 in the thickness direction (Z-axis direction). In other words, with respect to the ceramic substrate 10, the height of the filled liquid resin and the thickness of the resin sheet 20 are the same.

[0027] After the filling step, the liquid resin filled inside the through holes HL is irradiated with ultraviolet light to form a hardened resin coat 30 (step S7 in FIG. 3), thereby completing the manufacturing flow of the wiring board 100. By forming the resin coat 30, the resistor 40 arranged on the ceramic substrate 10 is covered with the hardened resin coat 30.

[0028] 9 is a schematic plan view of a wiring board 100z of a comparative example. In the wiring board 100z of the comparative example, unlike the wiring board 100 of the above embodiment shown in FIGS. 1 and 2, the resin coat 30 is not present, and the resistor 40 is covered with a resin sheet 20z. As shown in FIG. 9, the resin sheet 20z of the comparative example is a sheet in which a first sheet 21z, a second sheet 22, and a third sheet 23 each made of resin are laminated. The resistor 40 of the comparative example is disposed between the ceramic substrate 10 and the resin sheet 20z, and is therefore affected by the heating and pressure applied when bonding to the ceramic substrate 10.

[0029] FIG. 10 is a flowchart of a method for manufacturing a wiring board 100z of the comparative example. In the manufacturing flow shown in FIG. 10, a resin sheet 20z is created (step S11) in the same manner as in the embodiment (step S1 in FIG. 3). Next, a placement step is performed (step S12) to place a resistor 40 on a prepared ceramic substrate 10 in the same manner as in the embodiment (step S4 in FIG. 3). After the placement step is performed, an adjustment step is performed to adjust the resistance value of the resistor 40 by laser trimming in the same manner as in the embodiment (step S5 in FIG. 3). After the adjustment step, the ceramic substrate 10 and the resin sheet 20z arranged so as to cover the resistor 40 whose resistance value has been adjusted are joined (step S14), and the manufacturing flow of the wiring board 100z of the comparative example is completed.

[0030] As described above, the wiring board 100 of the present embodiment includes a thin-film resistor 40 arranged on the ceramic substrate 10, a resin sheet 20 arranged on the ceramic substrate 10, and a resin coat 30 covering the resistor 40 on the ceramic substrate 10. The resin sheet 20 is arranged on the ceramic substrate 10 in a portion where the resistor 40 is not arranged. The resin coat 30 is arranged so as to cover the resistor 40 on the ceramic substrate 10. That is, on the ceramic substrate 10 of the present embodiment, there are two resin layers: the resin sheet 20 arranged on the portion where the resistor 40 is not arranged, and the resin coat 30 covering the resistor 40. With this configuration, after applying heat and pressure to the resin sheet 20 to bond the resin sheet 20 and the ceramic substrate 10, the resistance value of the resistor 40 can be adjusted and the resin coat 30 can be formed so as to cover the resistor 40. In this way, since heating and pressurization for bonding the resin sheet 20 to the ceramic substrate 10 can be performed before the resistance value of the resistor 40 is adjusted, the temperature of heat applied when forming the resin coat 30 can be made lower than when bonding the resin sheet 20 to the ceramic substrate 10. Furthermore, the number of times and the heating time applied when forming the resin coat 30 can be made smaller than when bonding the resin sheet 20 to the ceramic substrate 10. That is, the thermal fluctuation applied to the resistor 40 when forming the resin coat 30 can be made smaller than the thermal fluctuation applied when bonding the resin sheet 20 to the ceramic substrate 10. That is, since the thermal fluctuation applied to the resistor 40 is suppressed, the resistance value of the resistor 40 can be adjusted with high accuracy. In addition, since the resistor 40 is covered with the resin coat 30, the resistor 40 can be protected from the effects of chemicals, oxidation, and the like. As a result, the accuracy of the resistance value of the resistor 40 can be improved in the wiring substrate 100 having a configuration in which the surface of the resistor 40 is covered with a resin layer (resin coat 30).

[0031] Moreover, the resin sheet 20 of this embodiment has a through hole HL penetrating the first surface 20A facing the ceramic substrate 10 and the second surface 20B located on the opposite side of the first surface 20A. The resistor 40 is disposed inside the through hole HL of the resin sheet 20 on the ceramic substrate 10 as shown in Figs. 1 and 2. The resin coat 30 is disposed so as to fill the inside of the through hole HL of the resin sheet 20 as shown in Fig. 2. That is, on the ceramic substrate 10, the resin sheet 20 has a shape surrounding the resistor 40 disposed in the through hole HL. With this configuration, the resin sheet 20 and the ceramic substrate 10 are bonded in a state in which the resistor 40 whose resistance value is not adjusted is disposed on the ceramic substrate 10, and then the resistance value of the resistor 40 is adjusted and the resin coat 30 is filled, thereby forming the wiring substrate 100. This makes it possible to easily form the wiring substrate 100 having a configuration in which the surface of the resistor 40 is covered with a resin layer (resin coat 30).

[0032] In addition, in the bonding process in the manufacturing method of the wiring board 100 of this embodiment, the resin sheet 20 is bonded to the ceramic substrate 10 so that the resistor 40 is disposed inside the through hole HL penetrating in the thickness direction. In the filling process, the through hole HL is filled with liquid resin so as to cover the resistor 40 whose resistance value has been adjusted in the adjustment process. In the bonding process of this embodiment, the resin sheet 20 is bonded onto the ceramic substrate 10 so that the resistor 40 disposed on the ceramic substrate 10 is disposed inside the through hole HL of the resin sheet 20. Thereafter, the resistance value of the resistor 40 disposed inside the through hole HL is adjusted by laser trimming, and the through hole HL is filled with liquid resin. As a result, it is possible to suppress the application of heat and pressure applied when the resin sheet 20 is bonded onto the ceramic substrate 10 to the resistor 40. In addition, the temperature of heat applied to form the liquid resin as the resin coat 30 and the number of times heat is applied are suppressed compared to when the resin sheet 20 is bonded. This suppresses thermal fluctuations in the resistor 40 whose resistance value has been adjusted, so that in this embodiment, the surface of the resistor 40 is covered with the resin coat 30 and the resistance value of the resistor 40 can be maintained in a state in which it is adjusted with high precision.

[0033] <Modifications of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the invention. For example, the following modifications are also possible.

[0034] <Variation 1> The wiring board 100 of the above embodiment is an example, and the configuration of the wiring board 100 can be modified as long as the resistor 40 is covered with a resin coat 30 different from the resin sheet 20. The wiring board 100 may be a circular or polygonal shape other than a rectangular shape in an XY plane perpendicular to the thickness direction. The ceramic board 10 may be formed of multiple layers, unlike the above embodiment. In this case, the layers other than the layer on which the resistor 40 is arranged and bonded to the resin sheet 20 may be formed of layers that do not contain ceramic as a main component. The resin sheet 20 may be a single layer or two layers, or may be formed of four or more layers.

[0035] The wiring layer arranged between the sheets 21 to 23 forming the resin sheet 20 is not limited to a predetermined wiring pattern, and may be a plain layer formed of a simple flat metal. The wiring layer may have vias penetrating the second sheet 22, for example. The material of the resistor 40 may be other than TaN, and may be a well-known material. The through hole HL of the resin sheet 20 may not be a hole with a rectangular cross section, and may be, for example, a circular shape. The resin sheet 20 may not have a shape surrounding the resistor 40 in the XY plane perpendicular to the thickness direction. For example, the through hole HL of the resin sheet 20 shown in FIG. 4 may have a shape in which the Y-axis positive side is open. The number of resistors 40 arranged on the ceramic substrate 10 may be two or more.

[0036] The position where resistor 40 is arranged on ceramic substrate 10 does not have to be in the center, and may be selected within the range that can be covered with resin coat 30. In the manufacturing flow of wiring substrate 100 shown in FIG. 3, the arrangement step (step S3) of arranging resistor 40 on ceramic substrate 10 may be performed after the bonding step (step S4) of bonding resin sheet 20 to ceramic substrate 10.

[0037] <Variation 2> Fig. 11 is a schematic cross-sectional view of a wiring board 100a. The resin coat 30a of the modified example shown in Fig. 11 is formed to have a form consisting of a plurality of layers 31 to 33. Furthermore, the resistor 40 may be disposed not only on the ceramic substrate 10 but also between layers 31 and 33 of the resin coat 30a consisting of the plurality of layers 31 to 33 formed in the through-hole HL of the resin sheet 20 as shown in Fig. 11. When the resistor 40 is disposed between layers 31 and 33 of the plurality of layers 31 to 33 forming the resin coat 30a as in the modified example shown in Fig. 11, the thickness of the plurality of layers 31 to 33 is adjusted, and thereby the position of the resistor 40 in the thickness direction is adjusted.

[0038] The wiring board 100a shown in Fig. 11 is manufactured by forming one layer 31 that forms the resin coat 30a in the through hole HL before the processing of the arrangement step (step S3) in the manufacturing flow (Fig. 3) of the above embodiment. After the layer 31 is formed, the layer 32 and the layer 33 are formed. Note that two layers 32 and 33 of the three layers 31 to 33 that form the resin coat 30a may be formed as one layer.

[0039] Although the present aspect has been described above based on the embodiment and modified examples, the above-mentioned embodiment of the aspect is intended to facilitate understanding of the present aspect and does not limit the present aspect. The present aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents are included in the present aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

[0040] The present invention can also be realized in the following forms. [Application example 1] A wiring board, A ceramic substrate; a thin film resistor disposed on the ceramic substrate; a first resin layer formed of resin and disposed on a portion of the ceramic substrate where the resistor is not disposed; a second resin layer formed of resin and covering the resistor on the ceramic substrate; A wiring board comprising: [Application example 2] The wiring board according to Application Example 1, the first resin layer has a through hole penetrating a first surface facing the ceramic substrate and a second surface located on the opposite side to the first surface; the resistor is disposed on the ceramic substrate inside the through hole of the first resin layer, The wiring board, wherein the second resin layer is filled inside the through hole of the first resin layer. [Application example 3] The wiring board according to the first or second aspect of the present invention, The second resin layer is composed of a plurality of layers, The wiring board, wherein the resistor is disposed between a plurality of layers constituting the second resin layer. [Application example 4] A method for manufacturing a wiring board, comprising: a step of disposing a thin-film resistor on a ceramic substrate; a bonding step of bonding a resin sheet, the resin sheet being made of resin and having a through hole penetrating in a thickness direction, onto the ceramic substrate such that the resistor is disposed inside the through hole; an adjustment step of adjusting a resistance value of the resistor by laser trimming; a filling step of filling the through hole with a liquid resin; A method for manufacturing a wiring board comprising: [Explanation of symbols]

[0041] 10...Ceramic substrate 20...Resin sheet (first resin layer) 20A…First side of resin sheet 20B: Second side of resin sheet 20z: Comparative example resin sheet 21,21z…1st sheet 22…Second seat 23…3rd seat 30, 30a...Resin coat (second resin layer) 31 to 33: Layers that form the resin coat 40…Resistor 41…Main body 42…Notch 100, 100a, 100z...wiring board CS...Cartesian coordinate system HL...Through hole

Claims

1. A wiring board, A ceramic substrate; a thin film resistor disposed on the ceramic substrate; a first resin layer formed of resin and disposed on a portion of the ceramic substrate where the resistor is not disposed; a second resin layer formed of a resin and covering the resistor on the ceramic substrate; Equipped with the first resin layer has a through hole penetrating a first surface facing the ceramic substrate and a second surface located on the opposite side to the first surface; the second resin layer is filled in the through hole of the first resin layer and is composed of a plurality of layers; A wiring board characterized in that the resistor is disposed on the ceramic substrate, inside the through hole of the first resin layer, and between multiple layers constituting the second resin layer.

2. A method for manufacturing a wiring board, comprising: a bonding step of bonding a resin sheet, which is made of resin and has through holes formed therein penetrating in a thickness direction, onto a ceramic substrate; filling the inside of the through hole with a liquid resin; a placement step of placing a thin-film resistor on the resin filled in the through hole; an adjustment step of adjusting a resistance value of the resistor by laser trimming; a filling step of filling the inside of the through hole with a liquid resin after the adjusting step; A method for manufacturing a wiring board comprising:

Images