Aggregate board and circuit board

Abstract

To reduce variations in resistance value caused by interaction between resistors having different compositions.SOLUTION: The collective board 1 includes a plurality of circuit boards. Each of the plurality of circuit boards includes a board body 11, a wiring 12, a plurality of resistors 13, and a third resistor 14. The substrate body 11 is made of ceramics. The wiring 12 is located on at least one surface of the substrate body 11. The plurality of resistance bodies 13 are a plurality of resistance bodies connected to the wiring 11, respectively, and include a first resistance body 13 _ 1 containing La and a second resistance body 13 _ 2 not containing La or having a smaller La content than the first resistance body 13 _ 1. The third resistance body 14 is positioned around at least one second resistance body 13 _ 2 of the plurality of second resistance bodies 13 _ 2 included in the plurality of resistance bodies 13 electrically independently of the wiring, and contains La.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] TECHNICAL FIELD The present disclosure relates to an aggregate substrate and a circuit board. [Background technology]

[0002] Substrates made of ceramics are sometimes used as circuit boards because they have excellent insulating properties and thermal conductivity.

[0003] Patent Document 1 discloses a circuit board in which a plurality of resistors with different compositions are formed on a circuit formation surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3564776 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned prior art has room for further improvement in terms of reducing variations in resistance value caused by interactions between resistors with different compositions.

[0006] One aspect of the embodiment has been made in consideration of the above, and aims to provide an aggregate substrate and a circuit board that can reduce variations in resistance value caused by interactions between resistors with different compositions. [Means for solving the problem]

[0007] An aggregate substrate according to one embodiment includes a plurality of circuit boards. Each of the plurality of circuit boards includes a substrate body, wiring, a plurality of resistors, and a third resistor. The substrate body is made of ceramic. The wiring is located on at least one surface of the substrate body. The plurality of resistors are each connected to the wiring, and include a first resistor containing La and a second resistor that does not contain La or has a lower La content than the first resistor. The third resistor is located around at least one of the second resistors included in the plurality of resistors, electrically independent of the wiring, and contains La. [Effects of the Invention]

[0008] According to one aspect of the embodiment, it is possible to reduce variations in resistance value caused by interactions between resistors with different compositions. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic plan view of a circuit board according to an embodiment. [Figure 2] FIG. 2 is an enlarged view of the periphery of a third resistor according to the embodiment. [Figure 3] FIG. 3 is a diagram showing the measurement results of the variation in resistance value of the second resistors for each of the aggregate substrates according to Examples 1 and 2 and Comparative Examples 1 and 2. In FIG. [Figure 4] FIG. 4 is a schematic plan view of a circuit board according to another embodiment 1. As shown in FIG. [Figure 5] FIG. 5 is an enlarged view of the periphery of a third resistor according to another embodiment 2. In FIG. [Figure 6] FIG. 6 is an enlarged view of the periphery of a third resistor according to another embodiment 3. In FIG. [Figure 7] FIG. 7 is an enlarged view of the periphery of a third resistor according to another fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a detailed description will be given of an embodiment (hereinafter referred to as an "embodiment") for carrying out an aggregate substrate and a circuit board according to the present disclosure, with reference to the drawings. Note that the aggregate substrate and the circuit board according to the present disclosure are not limited to the embodiment. Furthermore, each embodiment can be appropriately combined as long as the processing content is not contradictory. Furthermore, the same components in each of the following embodiments are given the same reference numerals, and duplicated explanations will be omitted.

[0011] Furthermore, in the following embodiments, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "perpendicular," or "parallel" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

[0012] In addition, in the drawings referred to below, for ease of understanding, an orthogonal coordinate system may be shown in which the X-axis, Y-axis, and Z-axis directions are defined as being perpendicular to each other, and the positive Z-axis direction is the vertically upward direction.

[0013] (Embodiment) First, the configuration of the circuit board according to the embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a schematic plan view of the circuit board according to the embodiment. Fig. 2 is an enlarged view of the periphery of the third resistor according to the embodiment.

[0014] As shown in FIG. 1, the circuit board 1 has a substrate body 11 made of ceramic. The substrate body 11 may be a plate-like member having a rectangular shape in a plan view. The substrate body 11 has a first surface, a second surface opposite the first surface, and multiple third surfaces (side surfaces) connected to each of the first and second surfaces. FIG. 1 shows the configuration of the first surface (here, the top surface) of the substrate body 11. The first surface (here, the top surface) of the substrate body 11 may be partitioned into regions A1 to A6 arranged in a matrix in directions (X-axis and Y-axis directions) along the edges of the first surface. Each of the regions A1 to A6 may be divided into individual pieces and function as an independent circuit board. That is, the circuit board 1 may be formed as an aggregate substrate, which is an aggregate of multiple circuit boards connected together. When the circuit board 1 is formed as an aggregate substrate, the circuit board may be referred to as an "aggregate substrate," and each of the regions A1 to A6 may be referred to as a "circuit board." The circuit board 1 may have six or more regions.

[0015] Ceramics such as aluminum oxide ceramics, zirconium oxide ceramics, composite ceramics of aluminum oxide and zirconium oxide, silicon nitride ceramics, aluminum nitride ceramics, silicon carbide ceramics, and mullite ceramics can be used as the substrate body 11. The substrate body 11 made of aluminum oxide ceramics has excellent workability while maintaining the mechanical strength required of the substrate body 11. Furthermore, the substrate body 11 made of aluminum nitride ceramics has high thermal conductivity and therefore excellent heat dissipation properties.

[0016] Wiring 12, mainly composed of metal such as copper and silver, is located on a first surface (here, the upper surface) of substrate body 11. Wiring 12 is located individually in each of areas A1 to A6. Wiring 12 is interrupted on the circuit, and the circuit may be connected via resistor 13.

[0017] A plurality of resistors 13 are positioned on the wiring 12. Each of the plurality of resistors 13 is connected to the wiring 12 and has a resistance value higher than that of the wiring 12.

[0018] The plurality of resistors 13 include a plurality of first resistors 13_1 and a plurality of second resistors 13_2. The first resistors 13_1 and the second resistors 13_2 may be thin-film resistors printed on the substrate body 11. At least one pair of the first resistor 13_1 and the second resistor 13_2 is located in each of the regions A1 to A6. The thickness of the resistors 13 may be, for example, 5 μm to 100 μm.

[0019] The first resistor 13_1 may have a rectangular shape in a plan view seen from a direction (Z-axis direction) perpendicular to the first surface (here, the top surface) of the substrate body 11. The first resistor 13_1 may have a shape other than a rectangular shape, for example, a circular shape, in a plan view seen from a direction (Z-axis direction) perpendicular to the first surface (here, the top surface) of the substrate body 11. The first resistor 13_1 may contain an insulating material and a conductive material. The first resistor 13_1 may contain, for example, glass as the insulating material. The first resistor 13_1 may also contain, as the conductive material, a conductive material containing lanthanum (La). For example, the first resistor 13_1 may contain lanthanum boride (LaB6) as the conductive material containing La. Such a first resistor 13_1 has a higher resistance value than the wiring 12.

[0020] Like the first resistor 13_1, the second resistor 13_2 may have a rectangular shape in a plan view seen from a direction (Z-axis direction) perpendicular to the first surface (here, the upper surface) of the substrate body 11. The second resistor 13_2 may contain an insulating material and a conductive material. The second resistor 13_2 may contain, for example, glass as the insulating material. The second resistor 13_2 may contain, as the conductive material, a conductive material that does not contain La or has a lower La content than the first resistor 13_1. For example, the second resistor 13_2 may contain a copper-nickel (CuNi)-based material as the conductive material that does not contain La. For example, the second resistor 13_2 may contain, as the conductive material having a lower La content than the first resistor 13_1, a smaller amount of LaB6 than the first resistor 13_1. The second resistor 13_2 has a resistance value higher than the wiring 12 and higher than the first resistor 13_1.

[0021] A third resistor 14 may be located around at least one of the second resistors 13_2, electrically independent of the wiring 12. For example, the third resistor 14 is located around each of all the second resistors 13_2 shown in Fig. 1. One or more third resistors 14 may be located around each of the second resistors 13_2.

[0022] The third resistor 14 may have a rectangular shape in a plan view seen from a direction (Z-axis direction) perpendicular to the first surface (here, the upper surface) of the substrate body 11. The third resistor 14 may contain an insulating material and a conductive material. The third resistor 14 may contain, for example, glass as the insulating material. The third resistor 14 may contain, as the conductive material, a conductive material containing La. For example, the third resistor 14 may contain LaB6 as the conductive material containing La. The third resistor 14 may have the same La content as the first resistor 13_1. The La content of the third resistor 14 may be smaller than the La content of the first resistor 13_1. The third resistor 14 may have a resistance value higher than the wiring 12 and the same as or higher than the first resistor 13_1.

[0023] The inventors of the present application have confirmed that in a circuit board having multiple resistors with different compositions, variations in resistance value occur due to interactions between the resistors. For example, in a circuit board 1 having a first resistor 13_1 containing LaB6 and a second resistor 13_2 having a different composition from the first resistor 13_1, the variation in resistance value of the second resistor 13_2 becomes large. This is thought to be due to the reducing effect of LaB6 contained in the first resistor 13_1.

[0024] Specifically, when the first resistor 13_1 and the second resistor 13_2 are fired in a manufacturing process of the circuit board 1, the oxygen concentration in the firing atmosphere around the first resistor 13_1 decreases due to a reduction action of the first resistor 13_1. As the oxygen concentration decreases, some effect occurs on the second resistor 13_2 adjacent to the first resistor 13_1, causing the resistance value of the second resistor 13_2 to fluctuate. That is, it is considered that the resistance value of the second resistor 13_2 decreases as the oxygen concentration decreases due to the first resistor 13_1.

[0025] The fluctuation range of the resistance value of the second resistor 13_2 varies depending on the arrangement position of the second resistor 13_2 on the circuit board 1. For example, on the circuit board 1, the second resistor 13_2 located in the region A1 may be surrounded by two first resistors 13_1 located in regions A1 and A2. Also, for example, the second resistor 13_2 located in the region A5 may be surrounded by six first resistors 13_1 located in regions A1 to A6. In such a case, the second resistor 13_2 located in the region A1 has fewer first resistors 13_1 around it than the second resistor 13_2 located in the region A5. Therefore, the degree of decrease in oxygen concentration is relatively small near the second resistor 13_2 located in the region A1. As a result, the change in the resistance value of the second resistor 13_2 is relatively small compared to the second resistor 13_2 located in the region A5.

[0026] In contrast, the second resistor 13_2 located in region A5 has a larger number of surrounding first resistors 13_1 than the second resistor 13_2 located in region A1. Therefore, the degree of decrease in oxygen concentration is relatively large near the second resistor 13_2 located in region A5, and as a result, the change in the resistance value of the second resistor 13_2 is relatively large. In this way, in the circuit board 1 including the first resistor 13_1 and the second resistor 13_2 having different compositions, the resistance value of the second resistor 13_2 varies due to the reducing action of LaB6 contained in the first resistor 13_1.

[0027] Therefore, in the circuit board 1 according to the embodiment, a third resistor 14 containing La is arranged around at least one of the plurality of second resistors 13_2. This configuration can reduce variations in the resistance values ​​of the second resistors 13_2 compared to when the third resistor 14 is not arranged around the second resistors 13_2. The third resistor 14 may be electrically independent from the wiring 12 that constitutes the circuit in the circuit board 1. In other words, the third resistor 14 does not need to function as an element that constitutes the circuit. By being independent from the circuit in this way, the third resistor 14 can be arranged freely.

[0028] That is, according to the circuit board 1 of the embodiment, by arranging the third resistor 14 containing La (i.e., LaB6) around the second resistor 13_2, the effect of the reduction action of LaB6 can be uniformly imparted to each second resistor 13_2. Therefore, since the fluctuation range of the resistance value can be uniformed regardless of the arrangement position of the second resistor 13_2, it is possible to suitably reduce the variation in the resistance value of the second resistor 13_2 caused by the reduction action between the first resistor 13_1 and the second resistor 13_2.

[0029] Furthermore, in the circuit board 1 according to the embodiment, the third resistor 14 may be positioned around each of the second resistors 13_2. This allows the second resistors 13_2 to be uniformly affected by the reducing action of LaB6 contained in the third resistor 14. Therefore, the circuit board 1 according to the embodiment can further preferably reduce the variation in the resistance value of the second resistors 13_2.

[0030] Here, a specific example of the arrangement of the third resistor 14 according to the embodiment will be described with reference to Fig. 2. Fig. 2 is an enlarged view showing the periphery of the third resistor 14 according to the embodiment. Fig. 2 shows the arrangement of the third resistor 14 located in region A1 of the substrate body 11 as a representative example, but the arrangement of the third resistors 14 located in the other regions A2 to A6 may also be similar to that shown in Fig. 2.

[0031] As shown in Figure 2, the third resistor 14 may be located on a straight line L passing through the center of one first resistor 13_1 and the center of one second resistor 13_2 adjacent to the one first resistor 13_1, and in a position sandwiching one second resistor 13_2 between itself and the one first resistor 13_1.

[0032] With this configuration, the effect of the reducing action of LaB6 can be efficiently imparted to one second resistor 13_2 from the first resistor 13_1 and the third resistor 14 positioned on either side of the second resistor 13_2, thereby further reducing the variation in the resistance value of the second resistor 13_2.

[0033] Furthermore, the shortest distance between the third resistor 14 and one of the second resistors 13_2 may be less than 10 mm. When the shortest distance between the third resistor 14 and one of the second resistors 13_2 is less than 10 mm, the influence of the reducing action of LaB6 is relatively large, and therefore, the variation in the resistance value of the second resistor 13_2 can be suitably reduced.

[0034] Next, a method for manufacturing the circuit board 1 according to the embodiment will be described. First, a metal paste that will become the wiring 12 is printed in a predetermined pattern on a first surface (here, the upper surface) of the substrate body 11 made of ceramic.

[0035] Next, the substrate body 11 on which the metal paste has been printed is fired under predetermined firing conditions to obtain the wiring 12.

[0036] Subsequently, on the wiring 12, a plurality of first resistor pastes to become the first resistors 13_1 and a plurality of second resistor pastes to become the second resistors 13_2 are printed.

[0037] Next, a third resistor paste that will become the third resistor 14 is printed around each of the plurality of second resistor pastes.

[0038] Then, the substrate body 11 on which the first resistor paste, the second resistor paste, and the third resistor paste have been printed is fired under predetermined firing conditions. In this way, the circuit board 1 according to the embodiment is obtained.

[0039] Below, we will explain in detail the variation in the resistance value of the second resistor 13_2 by giving an example in which the third resistor 14 is disposed around the second resistor 13_2 and a comparative example in which the second resistor 13_2 does not have a resistor disposed around it or has another resistor that does not contain La.

[0040] [Example 1] The aggregate substrate (sample No. 4) according to Example 1 was fabricated as follows. A metal paste to form the wiring 12 was printed on a first surface (here, the upper surface) of a ceramic substrate body 11, and the substrate body 11 with the printed metal paste was fired under predetermined firing conditions. Next, a plurality of first resistor pastes to form the first resistors 13_1 and a plurality of second resistor pastes to form the second resistors 13_2 were printed on the wiring 12. A resistor paste containing LaB6 (DuPont resistor paste: QP601) was used as the first resistor paste. A resistor paste having a lower La content than the first resistor paste (DuPont resistor paste: QP603) was used as the second resistor paste. Next, a third resistor paste to form the third resistors 14 was printed around each of the plurality of second resistor pastes. The third resistor paste used was a resistor paste (DuPont resistor paste: QP601) with the same La content as the first resistor paste. The substrate body 11, on which the first, second, and third resistor pastes had been printed, was fired under predetermined firing conditions to obtain an aggregate substrate (sample No. 4) according to Example 1. The first resistor 13_1 and the second resistor 13_2 each had dimensions of 3 mm × 3 mm and a thickness of 15 μm. The third resistor 14 had dimensions of 3 mm × 1.5 mm and a thickness of 15 μm. The first resistor 13_1 and the second resistor 13_2 were aligned with an 8 mm gap between them, with one side facing each other. The second resistor 13_2 was aligned with a 3 mm long side of the third resistor 14, with one side facing each other. A 2 mm gap was provided between the second resistor 13_2 and the third resistor 14. In other words, the first resistor 13_1, the second resistor 13_2, and the third resistor 14 were aligned in a straight line. The circuit board was designed to have a size of 10 mm x 10 mm x 0.6 mm after sintering. The assembly board had 10 x 10 circuit boards, for a total of 100 boards. The size of the assembly board was designed to be 120 mm x 120 mm x 0.6 mm after sintering. The assembly board had circuit boards arranged side by side, with so-called dummy sections arranged outside the arrangement of the circuit boards.

[0041] [Example 2] The aggregate substrate (sample No. 3) of Example 2 was fabricated under the same conditions as Example 1, except that a resistor paste (DuPont resistor paste: QP603) having a lower La content than the first resistor paste was used as the third resistor paste.

[0042] [Comparative Example 1] An aggregate substrate (sample No. 1) according to Comparative Example 1 was produced under the same conditions as in Example 1, except that no resistor paste was printed around each of the plurality of second resistor pastes.

[0043] Comparative Example 2 An aggregate substrate (sample No. 2) according to Comparative Example 2 was produced under the same conditions as in Example 1, except that a resistor paste not containing La (CuNi-based resistor paste) was used as the third resistor paste.

[0044] The variation in the resistance value of the second resistors 13_2 (coefficient of variation Cv: standard deviation (σ) / average value (x)) was measured for each of the aggregate substrates according to Examples 1 and 2 and Comparative Examples 1 and 2. The measurement results are shown in FIG. 3. FIG. 3 is a diagram showing the measurement results of the variation in the resistance value of the second resistors 13_2 for each of the aggregate substrates according to Examples 1 and 2 and Comparative Examples 1 and 2. The coefficient of variation Cv is an index indicating the magnitude of the variation, and a smaller coefficient of variation Cv indicates smaller variation.

[0045] As shown in FIG. 3, the coefficient of variation Cv of the aggregate substrates according to Examples 1 and 2 (samples No. 4 and 3) was 0.042 or less. In particular, the coefficient of variation Cv of sample No. 4 was below 0.04. In contrast, the coefficient of variation Cv of the aggregate substrates according to Comparative Examples 1 and 2 (samples No. 1 and 2) was greater than 0.045. This result indicates that the aggregate substrates according to Examples 1 and 2 (samples No. 4 and 3) can reduce the variation in the resistance value of the second resistors 13_2 compared to the aggregate substrates according to Comparative Examples 1 and 2 (samples No. 1 and 2). In the comparative samples Nos. 1 and 2, defective products that did not meet the specifications were produced. In contrast, in the case of samples Nos. 3 and 4, which are examples, no defective products were produced. In particular, in the case of sample No. 4, the resistance value of each product was close to the median resistance value and the variation was small.

[0046] (Another embodiment) Next, various other embodiments will be described with reference to Figures 4 to 7. In the various other embodiments below, the same components as those in the embodiments will be denoted by the same reference numerals, and redundant description will be omitted.

[0047] 4 is a schematic plan view of a circuit board according to another embodiment 1. In the circuit board 1 according to another embodiment 1, the arrangement of the third resistor 14 differs from that of the embodiment.

[0048] Specifically, in another embodiment 1, as shown in FIG. 4, the third resistor 14 is positioned around at least one second resistor 13_2 among the multiple second resistors 13_2 that is positioned adjacent to the outermost periphery of the first surface (here, the top surface) of the substrate main body 11.

[0049] For example, on the upper surface of the substrate body 11, of the plurality of second resistors 13_2, the second resistors 13_2 located in regions A1 to A3 are located adjacent to the edge 11a of the upper surface of the substrate body 11. A third resistor 14 is located around each of the second resistors 13_2 located in regions A1 to A3. Similarly, the second resistor 13_2 located in region A4 is located adjacent to the edge 11b of the upper surface of the substrate body 11. The third resistor 14 is located around the second resistor 13_2 located in region A4. Similarly, the second resistor 13_2 located in region A6 is located adjacent to the edge 11c of the upper surface of the substrate body 11. The third resistor 14 is located around the second resistor 13_2 located in region A6.

[0050] On the other hand, the second resistor 13_2 located in the region A5 is adjacent to the first resistor 13_1 located between the edge 11d of the upper surface of the substrate body 11 and the second resistor 13_2, but is not directly adjacent to the edge 11d of the upper surface of the substrate body 11. The third resistor 14 is not arranged around the second resistor 13_2 located in the region A5.

[0051] With this configuration, it is possible to omit arranging the third resistor 14 around the second resistor 13_2, which has a relatively large number of surrounding first resistors 13_1, as in the case of the second resistor 13_2 located in region A5. Around the second resistor 13_2, which has a relatively large number of surrounding first resistors 13_1, the degree of decrease in oxygen concentration is relatively large due to the reduction action of the first resistor 13_1. As a result, the resistance value of the second resistor 13_2 is considered to be sufficiently large. Therefore, even if the third resistor 14 is not arranged around the second resistor 13_2, it is considered possible to reduce variations in the resistance value of the second resistor 13_2 due to the reduction action of LaB6 contained in the first resistor 13_1. Therefore, according to the circuit board 1 according to another embodiment 1, it is possible to reduce variations in the resistance value of the second resistor 13_2 while reducing the number of third resistors 14 arranged. Although Figure 4 shows an example in which the third resistor 14 is arranged inside an individual circuit board 1, the third resistor 14 may also be arranged on the outer part of the board main body 11 of the circuit board 1.

[0052] Fig. 5 is an enlarged view of the periphery of a third resistor 14 according to another embodiment 2. Fig. 5 shows the arrangement of the third resistor 14 located in region A1 of the substrate body 11 as a representative example, but the arrangement of the third resistors 14 located in other regions A2 to A6 may also be similar to that shown in Fig. 5. In the circuit board 1 according to another embodiment 2, the arrangement of the third resistor 14 differs from that of the embodiment.

[0053] Specifically, the circuit board 1 according to another embodiment 2 may have a plurality of (here, three) third resistors 14 located around one second resistor 13_2, as shown in FIG. 5 . The plurality of third resistors 14 may be located at a plurality of positions within a predetermined distance from the center of the second resistor 13_2. The predetermined range may be a range in which the distance from the center of the second resistor 13_2 falls within ±10% of a specified distance. For example, the plurality of third resistors 14 may be located at a plurality of positions on a circle C1 within a predetermined distance from the center of the second resistor 13_2 to the circumference.

[0054] With this configuration, the effect of the reducing action of LaB6 can be more efficiently imparted to one second resistor 13_2 from the multiple third resistors 14 located around the second resistor 13_2. Therefore, according to the circuit board 1 of another embodiment 2, the variation in the resistance value of the second resistor 13_2 can be further preferably reduced.

[0055] Fig. 6 is an enlarged view of the periphery of a third resistor 14 according to another embodiment 3. Fig. 6 shows the arrangement of the third resistor 14 located in region A1 of the substrate body 11 as a representative example, but the arrangement of the third resistors 14 located in other regions A2 to A6 may also be similar to that shown in Fig. 6. In the circuit board 1 according to another embodiment 3, the arrangement of the third resistor 14 differs from that of the embodiment.

[0056] Specifically, as shown in FIG. 6, in a plan view seen from a direction perpendicular to the first surface (here, the top surface) of the substrate main body 11, the length L1 of the side of the third resistor 14 closest to one of the second resistors 13_2 may be greater than the length L2 of the side of one of the second resistors 13_2 facing that side.

[0057] With this configuration, the reduction effect of LaB6 can be applied to a wider range of the second resistor 13_2 from the third resistor 14. Therefore, according to the circuit board 1 of another embodiment 3, the variation in the resistance value of the second resistor 13_2 can be further reduced.

[0058] Fig. 7 is an enlarged view of the periphery of a third resistor 14 according to another embodiment 4. Fig. 7 shows the shape of the third resistor 14 located in region A1 of the substrate body 11 as a representative example, but the shapes of the third resistors 14 located in other regions A2 to A6 may also be similar to that shown in Fig. 7. In the circuit board 1 according to another embodiment 4, the shape of the third resistor 14 differs from that of the embodiment.

[0059] Specifically, as shown in FIG. 7, in a plan view seen from a direction perpendicular to the first surface (here, the top surface) of the substrate main body 11, the third resistor 14 may have an approximately L-shape along two side surfaces sandwiching a corner of one second resistor 13_2.

[0060] With this configuration, the effect of the reducing action of LaB6 can be more uniformly imparted to two side surfaces sandwiching a corner of one of the second resistors 13_2 from the third resistor 14. Therefore, according to the circuit board 1 of another embodiment 3, the variation in the resistance value of the second resistor 13_2 can be further suitably reduced.

[0061] (Other embodiments) In the above embodiment, the wiring 12, the plurality of resistors 13, and the third resistor 14 are arranged on the first surface (here, the upper surface) of the substrate body 11. However, the wiring 12, the plurality of resistors 13, and the third resistor 14 may be arranged on the second surface (here, the lower surface). In other words, the wiring 12, the plurality of resistors 13, and the third resistor 14 may be located on at least one of the first and second surfaces of the substrate body 11.

[0062] As described above, the assembly substrate (for example, the circuit board 1) according to the embodiment includes a plurality of circuit boards (for example, regions A1 to A6). Each of the plurality of circuit boards includes a substrate body (for example, the substrate body 11), wiring (for example, the wiring 12), a plurality of resistors (for example, the resistor 13), and a third resistor (for example, the third resistor 14). The substrate body is made of ceramics. The wiring is located on at least one surface (for example, the first surface) of the substrate body. The plurality of resistors are each connected to the wiring and include a first resistor (for example, the first resistor 13_1) containing La and a second resistor (for example, the second resistor 13_2) that does not contain La or has a lower La content than the first resistor. The third resistor is located around at least one second resistor among the plurality of second resistors included in the plurality of resistors, electrically independent from the wiring, and contains La. This makes it possible to reduce variations in resistance value (for example, the resistance value of the second resistor 13_2) due to interactions between resistors with different compositions (for example, the reducing action of LaB6).

[0063] The third resistor in the circuit board may have the same La content as the first resistor, or may have a lower La content than the first resistor, which allows the third resistor to exert the reducing effect of LaB6 on at least one second resistor.

[0064] Furthermore, the third resistors on the circuit board may be positioned around each of the second resistors, thereby further reducing variations in the resistance values ​​of the second resistors.

[0065] Furthermore, the third resistor in the circuit board may be located around at least one of the second resistors located adjacent to the outermost periphery on at least one surface of the plurality of second resistors, thereby reducing the number of third resistors and the variation in resistance values ​​of the second resistors.

[0066] Furthermore, the third resistor on the circuit board may be located on a line (for example, line L) passing through the center of one first resistor and the center of one second resistor adjacent to the one first resistor, and at a position where the one second resistor is sandwiched between the one first resistor and the third resistor, thereby making it possible to further suitably reduce variations in the resistance values ​​of the second resistors.

[0067] The circuit board may also have a plurality of third resistors located around one second resistor. The plurality of third resistors may be located at a plurality of positions within a predetermined distance from the center of one second resistor. This can further reduce the variation in the resistance value of the second resistors.

[0068] In addition, in a plan view of the third resistor in the circuit board seen from a direction perpendicular to at least one surface, the length of the side surface closest to one of the second resistors (for example, length L1) may be longer than the length of the side surface of one of the second resistors facing the side surface (for example, length L2), thereby making it possible to further suitably reduce variations in the resistance values ​​of the second resistors.

[0069] Furthermore, one second resistor in the circuit board may have a square shape including corners when viewed from a direction perpendicular to at least one surface. The third resistor may have a generally L-shape along two side surfaces sandwiching a corner of one second resistor when viewed from a direction perpendicular to at least one surface. This can further reduce variations in the resistance values ​​of the second resistors.

[0070] Further advantages and alternative embodiments may readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0071] 1 Circuit board (assembly board) 11 Board body 12 Wiring 13 Resistor 13_1 First resistor 13_2 Second resistor 14 Third Resistor L straight line A1~A6 area (circuit board)

Claims

1. a plurality of circuit boards; Each of the plurality of circuit boards includes: a substrate body made of ceramic; Wiring located on at least one surface of the substrate body; a plurality of resistors each connected to the wiring, the plurality of resistors including a first resistor containing La and a second resistor not containing La or having a smaller La content than the first resistor; a third resistor containing La, the third resistor being located around at least one of the second resistors included in the plurality of resistors and being electrically independent from the wiring; An assembly substrate having:

2. The third resistor on the circuit board is The La content of the first resistor is equal to or less than that of the first resistor. The assembly substrate according to claim 1 .

3. The third resistor on the circuit board is Located around each of the plurality of second resistors The assembly substrate according to claim 1 .

4. The third resistor on the circuit board is The second resistors are arranged around at least one second resistor that is located adjacent to the outermost periphery of the at least one surface. The assembly substrate according to claim 1 .

5. The third resistor on the circuit board is The second resistor is located on a straight line passing through the center of one of the first resistors and the center of one of the second resistors adjacent to the one of the first resistors, and is located at a position where the second resistor is sandwiched between the one of the first resistors. The assembly substrate according to claim 1 .

6. the circuit board has a plurality of the third resistors positioned around one of the second resistors, The plurality of third resistors The second resistor is located at each of a plurality of positions within a predetermined range of distance from the center of the second resistor. The assembly substrate according to claim 1 .

7. The third resistor on the circuit board is In a plan view seen from a direction perpendicular to the at least one surface, the length of a side surface closest to one of the second resistors is greater than the length of a side surface of one of the second resistors facing the side surface. The assembly substrate according to claim 1 .

8. One of the second resistors on the circuit board is When viewed from a direction perpendicular to the at least one surface, the rectangular shape includes corners, The third resistor is In a plan view seen from a direction perpendicular to the at least one surface, the second resistor has a substantially L-shape along two side surfaces sandwiching a corner of the second resistor. The assembly substrate according to claim 1 .

9. 2. The circuit board assembly according to claim 1, wherein the circuit board is obtained by dividing the circuit board into individual pieces.

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