Termination resistors and circuit boards

Abstract

To provide a termination resistor that achieves both high-frequency characteristics and a low profile, and can be mounted on a circuit board as a chip. [Solution] The terminating resistor 11 is a resistor set to a specific resistance value of 10 to 200 Ω. The terminating resistor 11 comprises a resistive layer 12 having a first surface 12a and a second surface 12b on the opposite side of the first surface 12a, a first electrode layer 13 laminated on the first surface 12a of the resistive layer 12, and a second electrode layer 14 laminated on the second surface 12b of the resistive layer 12. The resistive layer 12 is made of a resistive material having a resistivity ρ of 0.5 to 4.0 Ωcm.

Description

[Technical Field]

[0001] This invention relates to a terminating resistor and a circuit board. [Background technology]

[0002] In recent years, the rapid spread of high-speed communication technology has led to an expansion of demand for high-frequency electronic circuits. Various types of resistors are used in high-frequency electronic circuits. For example, in high-frequency communication using frequency bands of gigahertz or higher, signals may be reflected at the termination of transmission lines or at connections with bonding wires as they pass through transmission lines and bonding wires. When this reflection occurs, the signal quality deteriorates and communication errors may occur. In particular, transmission lines have a specific characteristic impedance (e.g., 50Ω), and reflection occurs due to impedance mismatch at the termination of transmission lines, etc. Termination resistors are designed to match this characteristic impedance and are connected to the termination of transmission lines, etc. By matching the impedance, signal reflection is prevented. In other words, by using termination resistors, signals are properly processed at the termination of transmission lines, reducing high-frequency losses, thereby suppressing signal attenuation and loss, and maintaining communication quality. For example, Patent Document 1 discloses the use of a chip resistor as a 50Ω termination resistor to achieve impedance matching. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 6438569 [Overview of the project] [Problems that the invention aims to solve]

[0004] As shown in Patent Document 1 (Figure 2), a typical wire-bonded resistor is schematically illustrated in Figure 6, and a circuit board on which the resistor is mounted is schematically illustrated in Figure 7. As shown in Figure 6, the resistor 1 comprises a sheet-like resistor 2 having a predetermined thickness and a predetermined cross-sectional area, two electrodes 3 and 4 formed on both sides of the resistor 2, and an insulating plate 5 supporting the resistor 2 and electrodes 3 and 4. The resistor 1 has an element thickness L from the bottom surface of the insulating plate 5 to the top surface of the resistor 2, and a mounting area A which is the sum of the surfaces of electrodes 3 and 4 and the surface of the resistor 2. As shown in Figure 7, the resistor 1 is mounted on an AlN substrate 6 that constitutes a circuit board. Each electrode 3 and 4 is connected to other elements E1 and E2 by wires 7. However, in high-frequency electronic circuits, the generation of parallel stray capacitance Cf between the two electrodes 3 and 4 and the AlN substrate 6 has been a problem as it adversely affects the frequency characteristics of the circuit, such as bandwidth limiting.

[0005] Furthermore, with the recent miniaturization and integration of high-frequency electronic circuits, the size of termination resistors mounted in the circuits is also becoming constrained. In particular, low-profile termination resistors are required to reduce the physical height of electronic components and integrated circuit packages. In addition, termination resistors also need to have a certain mounting area for mounting on circuit boards using surface mount device (SMD) technology, chip-on-chip (CoC) technology, flip-chip technology, etc. For example, a mounting area of ​​approximately 0.001 mm². 2 If the size is below a certain size (for example, about 0.01 mm), wire bonding becomes difficult. 2 The above-mentioned mounting area must be secured. On the other hand, the terminating resistor must be set to a specific resistance value within the range of 10 to 200 Ω (e.g., 50 Ω, 75 Ω, 110 Ω, 120 Ω, 150 Ω, 200 Ω) so that its resistance value matches the characteristic impedance of the transmission line, etc. Until now, no terminating resistor has existed that satisfies all of these requirements.

[0006] The object of the present invention is to provide a termination resistor that achieves both high-frequency characteristics and a low profile, and can be mounted on a circuit board as a chip, and a circuit board on which the termination resistor is mounted.

[0007] [Patent Document 1] Patent No. 6438569 [Means for solving the problem]

[0008] (Composition 1) One embodiment of the present invention is a terminating resistor set to a specific resistance value R between 10 and 200 Ω, A resistive layer having a first surface and a second surface on the opposite side of the first surface, A first electrode layer laminated on the first surface of the resistive layer, The resistive layer comprises a second electrode layer laminated on the second surface of the resistive layer, The resistive layer is characterized by being made of a resistive material having a resistivity ρ of 0.5 to 4.0 Ωcm.

[0009] (Configuration 2) A further embodiment of the present invention is a terminating resistor of configuration 1, more preferably characterized in that the resistive material is made of SiC.

[0010] (Composition 3) A further embodiment of the present invention is a termination resistor having configuration 1 or 2, more preferably wherein the element thickness L of the termination resistor is 0.2 mm or less, and the mounting area A is 0.01 mm 2 The above is the characteristic feature.

[0011] (Composition 4) A further embodiment of the present invention is a terminating resistor in any of configurations 1 to 3, more preferably wherein the mounting area A is 0.01 to 0.18 mm². 2 It is characterized by being such.

[0012] (Composition 5) In a terminating resistor according to a further aspect of the present invention, in any of the terminating resistors of Configurations 1 to 4, more preferably, the resistance value R of the terminating resistor is 50 Ω.

[0013] (Configuration 6) In a terminating resistor according to a further aspect of the present invention, in any of the terminating resistors of Configurations 1 to 5, the thicknesses of the first electrode layer and the second electrode layer are 10 μm or less.

[0014] (Configuration 7) A circuit board according to one aspect of the present invention includes an AlN substrate and any of the terminating resistors of Configurations 1 to 6 mounted on the AlN substrate.

[0015] (Configuration 8) In a circuit board according to a further aspect of the present invention, in the circuit board of Configuration 7, more preferably, the circuit board further includes a first element and a second element. The first electrode layer of the terminating resistor is wire-bonded to the first element, and the second electrode layer is electrically connected to a second element installed on a through hole or a conductor of the AlN substrate.

[0016] (Configuration 9) In a circuit board according to a further aspect of the present invention, in the circuit board of Configuration 7, more preferably, the circuit board further includes a first element and a second element. The first electrode layer of the terminating resistor is wire-bonded to the first element, and the second electrode layer is electrically connected to the second element through a through hole or a conductor formed in the AlN substrate. [Advantages of the Invention]

[0017] The termination resistor of the present invention prevents the generation of "parallel stray capacitance" caused by the termination resistor by laminating a first electrode layer and a second electrode layer on the first and second surfaces of the resistive layer, respectively, thereby improving the high-frequency characteristics when mounted on a circuit board. Furthermore, since the termination resistor is low-profile while ensuring a practical mounting area, its size does not become an obstacle during mounting on a circuit board or packaging. Therefore, the termination resistor of the present invention achieves both high-frequency characteristics and low profile, and enables mounting on a circuit board as a chip. [Brief explanation of the drawing]

[0018] [Figure 1] A schematic perspective view of a terminating resistor according to one embodiment of the present invention. [Figure 2] Cross-sectional view of the terminating resistor in Figure 1. [Figure 3] A schematic diagram showing a first example of a circuit board in which a terminating resistor of one embodiment of the present invention is mounted on an AlN substrate. [Figure 4] A schematic diagram showing a second example of a circuit board in which a terminating resistor according to one embodiment of the present invention is mounted on an AlN substrate. [Figure 5] A graph showing the high-frequency characteristics (reflection) of Examples 2 and 3 and Comparative Example 6 of the present invention. [Figure 6] A schematic perspective view showing a conventional resistor configuration. [Figure 7] A schematic diagram showing the first example of a circuit board in which resistors with a conventional configuration are mounted on an AlN substrate. [Figure 8] A schematic diagram showing a second example of a circuit board (configuration of Comparative Example 6) in which resistors with a conventional configuration are mounted on an AlN substrate. [Modes for carrying out the invention]

[0019] The terminating resistor 11 of one embodiment of the present invention is a chip configured to be mounted on a circuit board for high-frequency electronic circuits, and is used in SMD technology, CoC technology, flip-chip technology, etc. The terminating resistor 11 is connected to a transmission line or wire on the circuit board and has a resistance value R set to match the characteristic impedance of the transmission line or wire. By matching the resistance value R of the terminating resistor 11 to the characteristic impedance of the transmission line or wire, signal reflection and loss at the termination or connection can be minimized. This resistance value R is generally 10 to 200 Ω. In this embodiment, the resistance value R is set to 50 Ω for use in the termination or connection of high-frequency circuits. However, the resistance value R may take other specific values, such as 75 Ω (television transmission, satellite communication, etc.), 110 Ω (differential signal communication, high-speed digital communication, etc.), 120 Ω (certain digital signal standards, etc.), 150 Ω (certain digital signal standards, etc.), or 200 Ω (certain digital signal standards, etc.).

[0020] Figure 1 is a schematic perspective view of the terminating resistor 11 of this embodiment. Figure 2 is a cross-sectional view of the terminating resistor 11. As shown in Figure 1, the terminating resistor 11 has a three-dimensional shape with a rectangular surface. The terminating resistor 11 has length, width, and element thickness L, and its mounting area A is represented by the product of length and width (cross-sectional area). This element thickness L coincides with the direction in which the current flows through the element. The element thickness L is the distance between the outer surface of the first electrode layer 13 and the outer surface of the second electrode layer 14, but as will be described later, the thickness of the electrode layers 13 and 14 is sufficiently thin compared to the thickness of the resistive layer 12 and can therefore be ignored. In other words, the element thickness L substantially represents the thickness of the resistive layer 12 without considering the thickness of the electrode layers 13 and 14. It goes without saying that the terminating resistor of the present invention may have other three-dimensional shapes as long as it can perform its function.

[0021] As shown in Figure 2, the terminating resistor 11 comprises a resistive layer 12 having a first surface 12a and a second surface 12b on the opposite side of the first surface 12a, a first electrode layer 13 laminated on the first surface 12a of the resistive layer 12, and a second electrode layer 14 laminated on the second surface 12b of the resistive layer 12.

[0022] The resistive layer 12 is made of a resistive material having a resistivity of 0.5 to 4.0 Ω·cm. This resistive material is preferably selected from silicon carbide (SiC). The resistive layer 12 is formed to have a predetermined thickness and cross-sectional area. In this embodiment, tetraethoxysilane as a silicon source, novolac-type phenolic resin as a carbon source, maleic acid as a catalyst, and ethanol as a solvent were mixed to form a candy-like mixture. This candy-like mixture was gradually heated from room temperature to 200°C and thermally cured to form a resin-like solid. This resin-like solid was carbonized at 900°C under an argon atmosphere to form a carbide. This carbide was heated and held at 1900°C under an argon atmosphere to form silicon carbide powder. Furthermore, this silicon carbide powder was set in a hot press, and under vacuum conditions, it was gradually heated from room temperature to 1500°C and held thereafter, then pressurized, heated to 2300°C under an argon atmosphere and held thereafter, and then cooled to produce a sintered body of silicon carbide (SiC). The required resistivity can be achieved by adjusting the amount of impurities (nitrogen, carbon, metal, etc.) contained in the silicon carbide (SiC) sintered body (in this case, the amount of nitrogen contained in the silicon carbide (SiC) sintered body was adjusted to 40 ppm or less).

[0023] The first electrode layer 13 and the second electrode layer 14 are made of highly conductive metallic materials such as copper (Cu) or gold (Au). Furthermore, the thickness of the first electrode layer 13 and the second electrode layer 14 is preferably 10 μm or less. Specifically, the thickness of the first electrode layer 13 and the second electrode layer 14 is 3 μm. The thin plate-like first electrode layer 13 and the second electrode layer 14 may be bonded to the first surface 12a and the second surface 12b of the resistive layer 12, respectively, by pressure welding or sintering. Alternatively, the first electrode layer 13 and the second electrode layer 14 may be formed by sputtering or plating a metallic material onto the first surface 12a and the second surface 12b of the resistive layer 12, respectively.

[0024] The termination resistor 11 preferably has the following chip size. To reduce the chip height, the element thickness L of the termination resistor 11 is preferably 0.2 mm or less. In this embodiment, the element thickness L was set to 0.09 to 0.2 mm. Furthermore, to enable mounting the termination resistor 11 to a circuit board and / or to wire bonding connection with the termination resistor 11, the mounting area A is 0.01 mm². 2 The above is preferable. On the other hand, in order to avoid increasing the size of the chip in the planar direction, the mounting area A should be 0.18 mm². 2 The following is preferable:

[0025] Figure 3 is a schematic diagram showing an example (first embodiment) of a circuit board 10 in which the termination resistor 11 of this embodiment is mounted on an AlN substrate 16. As shown in Figure 3, the circuit board 10 comprises an AlN substrate 16 and a termination resistor 11 mounted on the AlN substrate 16. The circuit board 10 also comprises a first element E1 (not shown) and a second element E2 (capacitor). The second element E2 is installed on a through-hole 18 formed in the AlN substrate 16. In addition, a conductor such as gold plating or copper foil may be formed instead of the through-hole 18. The first electrode layer 13 of the termination resistor 11 is wire-bonded to the first element E1, and the second electrode layer 14 is electrically connected to the second element E2. In contrast, the conventional circuit configuration in Figure 6 has the same circuit configuration as in Figure 3, but the generation of a parallel stray capacitance Cf between the two electrodes 3 and 4 and the AlN substrate 6 adversely affects the frequency characteristics of the circuit, such as bandwidth limitation. In other words, in the circuit board 10, the first electrode layer 13 and the second electrode layer 14 are provided on the first surface 12a and the second surface 12b of the resistive layer 12, respectively. This prevents the generation of parallel stray capacitance Cf, which is a problem in conventional circuit configurations, due to the termination resistor 11. Therefore, the termination resistor 11 of this embodiment has improved high-frequency characteristics compared to conventional ones. Furthermore, in the circuit board 10 of Figure 3, the termination resistor 11 is mounted on the second element E2. However, since the termination resistor 11 is low-profile (element thickness L ≤ 0.2 mm) while securing a practical mounting area A, the risk of problems in mounting and packaging is reduced.

[0026] Figure 4 is a schematic diagram showing another example (second embodiment) of the circuit board 10 in which the termination resistor 11 of this embodiment is mounted on an AlN substrate 16. As shown in Figure 4, the circuit board 10' comprises an AlN substrate 16 and a termination resistor 11 mounted on the AlN substrate 16. The circuit board 10' also comprises a first element E1 and a second element E2. For example, the first element E1 is an electro-absorption modulated laser (EML), and the second element E2 is a multilayer ceramic capacitor (MLCC). The termination resistor 11 is placed on a conductor 19 formed on the AlN substrate 16. Alternatively, a through-hole may be formed instead of the conductor 19. The first electrode layer 13 of the termination resistor 11 is wire-bonded to the first element E1, and the second electrode layer 14 is electrically connected to the second element E2 via the conductor 19 (or through-hole) formed on the AlN substrate 16. Similarly, in the circuit board 10', the first electrode layer 13 and the second electrode layer 14 are provided on the first surface 12a and the second surface 12b of the resistive layer 12, respectively. This prevents the generation of parallel stray capacitance Cf, which was a problem in conventional circuit configurations, due to the termination resistor 11. Therefore, the termination resistor 11 of this embodiment has improved high-frequency characteristics compared to conventional designs. Furthermore, in the circuit board 10' of Figure 4, the termination resistor 11 is low-profile (element thickness L ≤ 0.2 mm) while securing a practical mounting area A, thus reducing the risk of problems in mounting and packaging. [Examples]

[0027] • Regarding low profile and implementability The termination resistor 11 of this embodiment has a resistive layer 12 formed of SiC having a resistivity of 0.5 to 4.0 Ω·cm, thereby achieving a desired resistance value (50 Ω), along with a low profile (T ≤ 0.2 mm), and meeting the mounting area requirement (S ≥ 0.01 mm) for mounting as a chip in an electronic circuit. 2It is possible to satisfy the following. Table 1 below shows the relationship between the element thickness L and the mounting area A when the resistance value is 50 Ω and SiC (specific resistance 0.5 to 4.0 Ω·cm) is selected as the resistance layer 12, and when other materials (specific resistance 0.0002, 0.03) are selected. Here, the equation R = specific resistance ρ × [element thickness L / mounting area A] holds.

[0028]

Table 1

[0029] According to Table 1, Examples 1 to 7 are the terminating resistors with a resistance value R of 50 Ω, where the resistance layer is SiC having a specific resistance ρ of 0.5 to 4.0 Ω·cm, and the element thickness L is set to 0.09 to 0.20 mm. In Examples 1 to 7, since the mounting area A is 0.01 to 0.16 mm 2 it can be seen that an area that can be mounted on the circuit board and is also connectable by wire bonding is ensured.

[0030] On the other hand, in Comparative Example 1, a resistance material with a specific resistance ρ of 0.0002 Ω·cm was used for the resistance layer. For example, the resistance material is a sintered body formed by mixing alumina powder and nichrome powder in a volume ratio of 20:80 and sintering. Comparative Examples 2 to 5 used a resistance material with a specific resistance ρ of 0.03 Ω·cm for the resistance layer. For example, the resistance material is a sintered body formed by mixing alumina powder and nichrome powder in a volume ratio of 70 to 80:30 to 20 and sintering. For the resistance materials of these comparative examples, refer to Japanese Patent Application Laid-Open No. 2023-78340 as the prior art.

[0031] In Comparative Examples 1 to 3, when the element thickness L was set to 0.10 to 0.20 mm, the mounting area A was 0.0012 mm 2 or less, and it was impossible to mount on the circuit board or connect by wire bonding. On the other hand, in Comparative Example 4, in order to achieve mountability, the mounting area A was 0.0330 mm 2However, the element thickness L was set to 5.5 mm, which was outside the standard thickness, making it impossible to reduce the profile. Furthermore, in Comparative Example 5, in order to achieve both a low profile and mountability, the element thickness L was set to 0.1 mm and the mounting area A was set to 0.0333 mm². 2 However, the condition for the resistance value R could not be met.

[0032] Table 2 shows the relationship between element thickness L and mounting area A when the resistance value is set to 100Ω and SiC (resistivity 0.5~4.0Ω·cm) is selected as the resistive layer 12, and when other materials (resistivity 0.0002, 0.03) are selected. Here again, the formula R = resistivity ρ × [element thickness L / mounting area A] holds true.

[0033] [Table 2]

[0034] According to Table 2, Examples 8-14 are terminating resistors with a resistance value R of 100Ω, where the resistive layer is made of SiC with a resistivity ρ of 0.5-4.0Ω·cm, and the element thickness L is set to 0.09-0.20mm. In Examples 8-14, the mounting area A is 0.01-0.08mm². 2 Therefore, it was found that there is enough area to mount on a circuit board and to allow for wire bonding connections.

[0035] On the other hand, Comparative Example 7 used a resistive material with a resistivity ρ of 0.0002 Ω·cm for the resistive layer. For example, the resistive material consists of a sintered body obtained by mixing alumina powder and nichrome powder in a volume percentage ratio of 20:80 and sintering them. Comparative Examples 8 to 11 used a resistive material with a resistivity ρ of 0.03 Ω·cm for the resistive layer. For example, the resistive material consists of a sintered body obtained by mixing alumina powder and nichrome powder in a volume percentage ratio of 70-80:30-20 and sintering them. For information on the resistive materials of these comparative examples, please refer to Japanese Patent Application Publication No. 2023-78340 as prior art.

[0036] In Comparative Examples 7-9, when the element thickness L was set to 0.10-0.20 mm, the mounting area A was 0.0006 mm². 2 As a result, mounting to the circuit board and wire bonding connections were impossible. On the other hand, in comparative example 10, in order to achieve mountability, the mounting area A was set to 0.0170 mm². 2 However, the element thickness L was set at 5.66 mm, which was outside the standard thickness, making it impossible to reduce the profile. Furthermore, in Comparative Example 11, in order to achieve both a low profile and mountability, the element thickness L was set to 0.1 mm and the mounting area A was set to 0.0169 mm². 2 However, the condition for the resistance value R could not be met.

[0037] Table 3 shows the relationship between element thickness L and mounting area A when the resistance value is set to 25Ω and SiC (resistivity 0.5~4.0Ω·cm) is selected as the resistive layer 12, and when other materials (resistivity 0.0002, 0.03) are selected. Here again, the formula R = resistivity ρ × [element thickness L / mounting area A] holds true.

[0038] [Table 3]

[0039] According to Table 3, Examples 15-21 are terminating resistors with a resistance R of 25Ω, where the resistive layer is made of SiC with a resistivity ρ of 0.5-4.0Ω·cm, and the element thickness L is set to 0.09-0.20mm. In Examples 15-21, the mounting area A is 0.04-0.18mm². 2 Therefore, it was found that there is enough area to mount on a circuit board and to allow for wire bonding connections.

[0040] On the other hand, Comparative Example 12 used a resistive material with a resistivity ρ of 0.0002 Ω·cm for the resistive layer. For example, the resistive material consists of a sintered body obtained by mixing alumina powder and nichrome powder in a volume percentage ratio of 20:80 and sintering them. Comparative Examples 13 to 16 used a resistive material with a resistivity ρ of 0.03 Ω·cm for the resistive layer. For example, the resistive material consists of a sintered body obtained by mixing alumina powder and nichrome powder in a volume percentage ratio of 70-80:30-20 and sintering them. For information on the resistive materials of these comparative examples, please refer to Japanese Patent Publication No. 2023-78340 as prior art.

[0041] In comparative examples 12-14, when the element thickness L was set to 0.10-0.20 mm, the mounting area A was 0.003 mm². 2 As a result, mounting to the circuit board and wire bonding connections were impossible. On the other hand, in comparative example 10, in order to achieve mountability, the mounting area A was set to 0.0679 mm². 2 However, the element thickness L was set at 5.66 mm, which was outside the standard thickness, making it impossible to reduce the profile. Furthermore, in Comparative Example 16, in order to achieve both a low profile and mountability, the element thickness L was set to 0.1 mm and the mounting area A was set to 0.0682 mm². 2 However, the condition for the resistance value R could not be met.

[0042] • Regarding high-frequency characteristics The high-frequency characteristics of a circuit board equipped with the termination resistor of the present invention were evaluated. First, a circuit board equipped with the termination resistor of the present invention (Examples 2 and 3) (configuration shown in Figure 4) was fabricated. As Comparative Example 6, a circuit board shown in Figure 7 was fabricated. The circuit boards of the Examples (Figure 4) and Comparative Example 6 (Figure 8) have the same basic configuration, but differ in that the structure shown in Figure 8 uses a conventional resistor. That is, as shown in Figure 8, the two electrodes 3 and 4 provided on both sides of the resistive element 2 of the resistor 1 are connected to the first element E1 and the second element E2, respectively, via two wires 17. Here, the resistor used in Comparative Example 6 operates at 50Ω, and its dimensions are an element thickness L of 0.42 mm and a mounting area A of 0.1872 mm². 2It was designed to meet these requirements. The reflection characteristics in the high-frequency band (gigahertz band) of Examples 2 and 3 and Comparative Example 6 were evaluated and compared. The evaluation method is as follows.

[0043] <Evaluation Method> The resistance of termination resistors mounted on a circuit board with a GSG transmission line was evaluated in S11 using a network analyzer (Keysight, model number: PNA) via a GSG probe.

[0044] Figure 5 is a graph showing frequency (GHz) versus reflection (dB) for Examples 2 and 3 and Comparative Example 6. Here, a smaller reflection (dB) (i.e., a larger negative value) indicates superior high-frequency characteristics. Figure 5 shows that the reflection of Comparative Example 6 is significantly larger than that of Examples 2 and 3. Therefore, it is confirmed that mounting the termination resistor of the present invention on a circuit board without generating stray capacitance improves the high-frequency characteristics of the circuit board.

[0045] The present invention is not limited to the embodiments described above, and can be implemented in various forms as long as they fall within the technical scope of the present invention. [Explanation of Symbols]

[0046] 1 resistor 2 resistors 3, 4 electrodes 5. Insulating board 6 AlN substrate 7 wires 10 Circuit boards 11 Termination resistor 12 resistance layer 12a 1st page 12b Side 2 13 First electrode layer 14 Second electrode layer 16 AlN substrate 17 wires 18 through holes 19 Conductors A. Implementation area L element height E1 First element E2 Second element Cf stray capacity

Claims

1. A terminating resistor set to a specific resistance value R between 10 and 200 Ω, A resistive layer having a first surface and a second surface on the opposite side of the first surface, A first electrode layer laminated on the first surface of the resistive layer, The resistive layer comprises a second electrode layer laminated on the second surface of the resistive layer, The terminating resistor is characterized in that the resistive layer is made of a resistive material having a resistivity ρ of 0.5 to 4.0 Ωcm.

2. The terminating resistor according to claim 1, characterized in that the resistive material is made of SiC.

3. The element thickness L of the termination resistor is 0.2 mm or less, and the mounting area A is 0.01 mm. ２ The terminating resistor according to claim 2, characterized in that it is as described above.

4. The aforementioned mounting area A is 0.01 to 0.18 mm ２ The terminating resistor according to claim 3, characterized in that it is the same as the present invention.

5. The terminating resistor according to claim 4, characterized in that the resistance value R of the terminating resistor is 50Ω.

6. The termination resistor according to claim 5, characterized in that the thickness of the first electrode layer and the second electrode layer is 10 μm or less.

7. A circuit board comprising an AlN substrate and a terminating resistor according to any one of claims 1 to 6 mounted on the AlN substrate.

8. The circuit board further comprises a first element and a second element, The circuit board according to claim 7, characterized in that the first electrode layer of the terminating resistor is wire-bonded to the first element, and the second electrode layer is electrically connected to a second element installed on a through-hole or conductor of the AlN substrate.

9. The circuit board further comprises a first element and a second element, The circuit board according to claim 7, characterized in that the first electrode layer of the terminating resistor is wire-bonded to the first element, and the second electrode layer is electrically connected to the second element via through-holes or conductors formed in the AlN substrate.

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