Chip resistor and method for manufacturing chip resistor

Abstract

This chip resistor comprises a substrate, a first electrode and a second electrode, and a resistor. A first trimming groove and a second trimming groove are formed in the resistor. The first trimming groove has a first linear portion and a second linear portion. The first linear portion extends from a first end edge of the resistor toward a second end edge thereof along a second direction intersecting a first direction. The second linear portion extends from a distal-end portion of the first linear portion toward the second trimming groove. The second trimming groove has a third linear portion and a curved portion. The third linear portion extends from the first end edge of the resistor toward the second end edge thereof. The curved portion extends from a distal-end portion of the third linear portion toward the first trimming groove. The curved portion is convex in a direction from the first end edge toward the second end edge.

Description

Chip resistor and method for manufacturing chip resistor

[0001] The present disclosure generally relates to a chip resistor and a method for manufacturing the same, and more particularly to a chip resistor including a pair of electrodes and a resistive element, and a method for manufacturing the same.

[0002] Patent Document 1 discloses a chip resistor having a substrate, a resistor element having a trimming groove formed therein for adjusting the resistance value, and electrodes formed on both sides of the resistor element.

[0003] Patent Document 2 discloses a chip resistor having a resistive film (resistive element) formed on the upper surface of a chip substrate. The resistive film has a first recessed groove and a second recessed groove formed therein for adjusting the resistance value.

[0004] JP 2019-169598 A JP 2005-244060 A

[0005] In a chip resistor such as that described in Patent Document 1, there is a risk that the resistance value will change due to a rise in the temperature around the trimming groove when current is applied, resulting in a decrease in reliability.

[0006] In chip resistors such as those described in Patent Document 2, there is a demand for improving reliability while adjusting the resistance value of the resistor with high precision.

[0007] A chip resistor according to one aspect of the present disclosure includes a substrate, a first electrode and a second electrode provided at both ends of one surface of the substrate in a first direction, and a resistor provided on the one surface of the substrate between the first electrode and the second electrode. The resistor has a first trimming groove and a second trimming groove aligned in the first direction. The first trimming groove has a first linear portion and a second linear portion. The first linear portion extends along a second direction intersecting the first direction from a first edge of the resistor in the second direction to a tip portion toward a second edge of the resistor opposite the first edge in the second direction. The second linear portion extends from the tip portion of the first linear portion along the first direction toward the second trimming groove. The second trimming groove has a third linear portion and a curved portion. The third linear portion extends along the second direction from the first edge of the resistor toward the second edge to a tip portion. The curved portion extends from the tip end portion of the third linear portion toward the tip end portion of the first trimming groove, and has a curved shape that is convex in a direction from the first edge toward the second edge of the resistor.

[0008] A method for manufacturing a chip resistor according to one aspect of the present invention includes the steps of forming first and second electrodes at both ends in a first direction on one surface of a substrate, forming a resistor between the first and second electrodes on the one surface of the substrate, and forming first and second trimming grooves aligned in the first direction in the resistor. The first trimming groove has a first linear portion and a second linear portion. The first linear portion extends along a second direction intersecting the first direction from a first edge of the resistor in the second direction to a tip portion toward a second edge of the resistor opposite the first edge in the second direction. The second linear portion extends from the tip portion of the first linear portion along the first direction toward the second trimming groove. The second trimming groove has a third linear portion and a curved portion. The third linear portion extends along the second direction from the first edge of the resistor toward the second edge to a tip portion. The curved portion extends from the tip end portion of the third linear portion toward the first trimming groove and has a curved shape that is convex in a direction from the first edge toward the second edge of the resistor.

[0009] A chip resistor according to one aspect of the present disclosure includes a substrate, a first electrode and a second electrode provided at both ends of one surface of the substrate in a first direction, and a resistor provided between the first electrode and the second electrode on the one surface of the substrate. The resistor has a serpentine portion, a first rectangular portion, and a second rectangular portion. A first trimming groove, a second trimming groove, and a third trimming groove are formed in the resistor. The first rectangular portion is connected to the serpentine portion and the first electrode. The second rectangular portion is connected to the serpentine portion and the second electrode. The first trimming groove is formed in the first rectangular portion and extends along a second direction intersecting the first direction from a first edge of the resistor in the second direction to a second edge opposite the first edge of the resistor in the second direction. The second trimming groove is formed in the second rectangular portion and extends along the second direction from the second edge of the resistor toward the first edge. The third trimming groove is formed in the first rectangular portion between the first trimming groove and the meandering portion, and extends along the second direction from the first edge of the resistor toward the second edge to a tip thereof, the tip of the third trimming groove being located closer to the first edge than a reference line connecting an intersection of the boundary between the first rectangular portion and the meandering portion and the first edge.

[0010] A method for manufacturing a chip resistor according to one aspect of the present invention includes the steps of forming a first electrode and a second electrode on both ends of a surface of a substrate in a first direction, and forming a resistor between the first electrode and the second electrode on the surface of the substrate. The steps of forming the resistor include a first step, a second step, a third step, and a fourth step. In the first step, a serpentine portion, a first rectangular portion connected to the serpentine portion and the first electrode, and a second rectangular portion connected to the serpentine portion and the second electrode are formed on the surface of the substrate. In the second step, a first trimming groove is formed in the first rectangular portion along a second direction intersecting the first direction, the first trimming groove extending from a first edge of the resistor in the second direction toward a second edge opposite the first edge of the resistor in the second direction to a tip thereof. In the third step, a second trimming groove is formed in the second rectangular portion along the second direction, the second trimming groove extending from the second edge of the resistor toward the first edge. In the fourth step, a third trimming groove is formed in the first rectangular portion between the first trimming groove and the meandering portion, the third trimming groove extending along the second direction from the first edge of the resistor toward the second edge to a tip thereof, the tip of the third trimming groove being located closer to the first edge than a reference line connecting an intersection of the boundary between the first rectangular portion and the meandering portion and the first edge.

[0011] According to the present disclosure, it is possible to provide a chip resistor and a method for manufacturing a chip resistor that can adjust the resistance value of a resistor with high precision while improving reliability.

[0012] FIG. 1 is a top view of a chip resistor according to one aspect of embodiment 1. FIG. 2 is a cross-sectional view of the same chip resistor. FIG. 3A is a diagram showing a simulation result of current density distribution in a resistor of a comparative example. FIG. 3B is a diagram showing a simulation result of temperature distribution in the resistor of the same. FIG. 4A is a diagram showing a simulation result of current density distribution in a resistor included in a chip resistor according to one aspect of embodiment 1. FIG. 4B is a diagram showing a simulation result of temperature distribution in the resistor of the same. FIG. 5 is a top view of a chip resistor according to a modified example. FIG. 6 is a top view of a chip resistor according to one aspect of embodiment 2. FIG. 7 is a cross-sectional view of the same chip resistor. FIG. 8 is a diagram showing a temperature distribution of a resistor included in the chip resistor. FIG. 9 is a diagram showing a temperature distribution of a resistor of a comparative example. FIG. 10 is a diagram showing a temperature distribution of a resistor included in a chip resistor according to one aspect of embodiment 2. FIG. 11 is a diagram showing a temperature distribution of a resistor of a comparative example. FIG. 12 is a top view of a chip resistor according to modified example 101 of embodiment 2. FIG. 13 is a top view of a chip resistor according to a modified example 102 of the second embodiment.

[0013] The chip resistor 1 according to the first embodiment will be described below with reference to the drawings. The figures described in the following embodiments are schematic diagrams, and the ratios of the sizes and thicknesses of the components do not necessarily reflect the actual dimensional ratios. Furthermore, the configurations described in the following embodiments are merely examples of the present disclosure. The present disclosure is not limited to the following embodiments, and various modifications are possible depending on the design, etc., as long as the effects of the present disclosure can be achieved.

[0014] In the following description, the long side direction of the chip resistor 1 is referred to as the "X-axis direction," the short side direction of the chip resistor 1 as the "Y-axis direction," and the thickness direction of the chip resistor 1 as the "Z-axis direction." The X-axis, Y-axis, and Z-axis defining these directions are perpendicular to one another. Note that "perpendicular" in this disclosure is a concept that includes approximately perpendicular, and includes a range of 90°±10°. Furthermore, these directions are merely examples and are not intended to limit the directions in which the chip resistor 1 is used. Furthermore, the arrows indicating the "X-axis direction," "Y-axis direction," and "Z-axis direction" in the drawings are merely shown for the purpose of explanation and have no substance.

[0015] (1-1) Overview First, an overview of the chip resistor 1 according to this embodiment will be described.

[0016] As shown in Figures 1 and 2, the chip resistor 1 comprises a substrate 2, a first electrode (first upper surface electrode) 3 and a second electrode (second upper surface electrode) 4 respectively provided at both ends in a first direction (X-axis direction) of one surface (surface) 21 of the substrate 2, and a resistor 5 provided between the first electrode 3 and the second electrode 4 on one surface 21 of the substrate 2.

[0017] The resistor 5 has a first trimming groove 11 and a second trimming groove 12 aligned in a first direction.

[0018] The first trimming groove 11 has a first linear portion S1 and a second linear portion S2. The first linear portion S1 extends along a second direction (Y-axis direction) intersecting the first direction from a first edge 51 of the resistor 5 in the second direction toward a second edge 52 of the resistor 5 in the second direction to a tip portion E1. The second linear portion S2 extends from the tip portion E1 of the first linear portion S1 along the first direction toward the second trimming groove 12 to a tip portion E2.

[0019] The second trimming groove 12 has a third straight line portion S3 and a curved line portion C1. The third straight line portion S3 extends in the second direction from the first edge 51 toward the second edge 52 to a tip portion E3. The curved line portion C1 extends from the tip portion E3 of the third straight line portion S3 toward the first trimming groove 11 to a tip portion F1. The curved line portion C1 is curved and convex in the direction from the first edge 51 toward the second edge 52.

[0020] In this disclosure, the "tip portion" of each portion of the grooves (first trimming groove 11 and second trimming groove 12) refers to a portion having a certain range that includes the most distal end of each portion in the extension direction. As an example, the "tip portion" is a circular region whose diameter is the width dimension of the groove, and is a region that includes the most distal end of each portion in the extension direction on the outer periphery of the circular region.

[0021] It has been confirmed through simulation that when a predetermined DC voltage is applied to the resistor 5 of this embodiment, the current density tends to increase in the second direction toward the second edge 52 (see FIG. 4A ). Note that the phrase "applying a predetermined DC voltage" here refers to applying a predetermined DC voltage between the first electrode 3 and the second electrode 4 to which the resistor 5 is connected.

[0022] Because the first trimming grooves 11 are formed in portions of the resistor 5 where the current density is relatively low, the effect of forming the first trimming grooves 11 on the resistance value of the resistor 5 is small. Therefore, the resistance value of the resistor 5 can be adjusted with high precision by adjusting the length and shape of the first trimming grooves 11. Furthermore, the second trimming grooves 12 are formed to adjust the resistance value of the resistor 5 by changing the current path in the resistor 5. Because a portion of the second trimming grooves 12 is formed in portions of the resistor 5 where the current density is higher than that of the first trimming grooves 11, the effect of forming the second trimming grooves 12 on the resistance value of the resistor 5 is greater than that of the first trimming grooves 11.

[0023] According to the above configuration, because the curved portion C1 is curved in a convex shape extending from the first edge 51 to the second edge 52, electric field concentration is unlikely to occur and high-temperature areas (hot spots) are unlikely to occur even when the apex P1 of the curved portion C1 is formed in a region of high current density in the resistor 5. Therefore, according to the above configuration, the shape of the curved portion C1 of the second trimming groove 12 suppresses changes in the resistance value of the resistor 5 due to temperature increases, thereby improving the reliability of the chip resistor 1, while the resistance value of the resistor 5 can be adjusted with high precision by the first trimming groove 11.

[0024] (1-2) Details The chip resistor 1 according to this embodiment will be described in detail with reference to the drawings.

[0025] (1-2-1) Basic Configuration of Chip Resistor The chip resistor 1 is a chip resistor for surface mounting (SMT: Surface Mount Technology) that is mounted on the surface (mounting surface) of a printed circuit board using, for example, a surface mounter. In this embodiment, as an example, the chip resistor 1 is a thick-film chip resistor.

[0026] 1 and 2, the chip resistor 1 has a substrate 2, a first upper surface electrode 3, a second upper surface electrode 4, and a resistor 5. As shown in Fig. 2, the chip resistor 1 further has a first lower surface electrode 33, a second lower surface electrode 34, a first end surface electrode 35, a second end surface electrode 36, a pair of first plating layers 37, and a pair of second plating layers 38. The chip resistor 1 also has a glass protective film 41 and a resin protective film 42.

[0027] (1-2-2) Substrate The substrate 2 is an insulating substrate made of an insulating material. For example, the substrate 2 is made of Al ２ O ３ It is composed of alumina containing 96% of

[0028] As an example, the substrate 2 is formed in a rectangular shape with its longitudinal direction along the X-axis direction (first direction), its lateral direction along the Y-axis direction (second direction), and its thickness direction along the Z-axis direction.

[0029] (1-2-3) Top Surface Electrodes The first top surface electrode 3 and the second top surface electrode 4 are provided at opposite ends of the surface 21 of the substrate 2 in the X-axis direction. More specifically, the first top surface electrode 3 is provided at the end of the surface 21 facing the negative side of the X-axis. The second top surface electrode 4 is provided at the end of the surface 21 facing the positive side of the X-axis.

[0030] The first upper surface electrode 3 and the second upper surface electrode 4 are formed by printing a thick film material containing a metal such as silver as a main material on the surface 21 and then firing it.

[0031] 2, the first lower surface electrode 33 and the second lower surface electrode 34 are provided on opposite ends of the rear surface 22 of the substrate 2 in the X-axis direction. More specifically, the first lower surface electrode 33 is provided on the end of the rear surface 22 in the negative direction of the X-axis. The second lower surface electrode 34 is provided on the end of the rear surface 22 in the positive direction of the X-axis.

[0032] The first lower surface electrode 33 and the second lower surface electrode 34 are formed by printing a thick film material containing a metal such as silver as a main component on the rear surface 22 and then firing the printed material. The first lower surface electrode 33 and the second lower surface electrode 34 are provided at positions corresponding to the first upper surface electrode 3 and the second upper surface electrode 4, respectively, in the Z-axis direction.

[0033] 2, the first end surface electrode 35 and the second end surface electrode 36 are provided on a pair of side surfaces 23 opposite each other in the X-axis direction of the substrate 2. More specifically, the first end surface electrode 35 is provided on the side surface 23 in the negative direction of the X-axis. The second end surface electrode 36 is provided on the side surface 23 in the positive direction of the X-axis.

[0034] The first end surface electrode 35 electrically connects the first upper surface electrode 3 and the first lower surface electrode 33. The second end surface electrode 36 electrically connects the second upper surface electrode 4 and the second lower surface electrode 34.

[0035] The first end surface electrode 35 and the second end surface electrode 36 are formed (deposited) by printing a material made of silver and synthetic resin on the pair of side surfaces 23 .

[0036] (1-2-6) First Plating Layer The pair of first plating layers 37 is made of, for example, nickel plating. The pair of first plating layers 37 covers the first end surface electrode 35 and the second end surface electrode 36, respectively, at both ends of the substrate 2 in the X-axis direction.

[0037] (1-2-7) Second Plating Layer The pair of second plating layers 38 is made of, for example, tin plating. The pair of second plating layers 38 covers the pair of first plating layers 37 at both ends of the substrate 2 in the X-axis direction, respectively.

[0038] (1-2-8) Glass Protective Film The glass protective film 41 is a film for protecting the resistor 5. As shown in FIG. 1, the glass protective film 41 covers the entire resistor 5. The glass protective film 41 is made of, for example, lead oxide glass. The glass protective film 41 is formed (deposited) by, for example, screen printing. Note that the glass protective film 41 is not limited to lead oxide glass, and may be made of, for example, silicate glass.

[0039] (1-2-9) Resin Protective Film The resin protective film 42 is made of, for example, epoxy resin, and covers the entire glass protective film 41. The resin protective film 42 is formed (deposited) by, for example, applying epoxy resin by screen printing and then thermally curing the epoxy resin.

[0040] (1-2-10) Resistor The resistor 5 is provided on the front surface (one surface) 21 of the substrate 2 between the first upper surface electrode 3 and the second upper surface electrode 4. Both ends of the resistor 5 in the X-axis direction are connected to the first upper surface electrode 3 and the second upper surface electrode 4, respectively.

[0041] The resistor 5 is formed by printing a thick film material made of, for example, about 10 wt % lead ruthenate, about 53 wt % glass, and about 37 wt % solvent on the surface 21 of the substrate 2, followed by baking. The resistor 5 is generally rectangular and has a first edge 51 and a second edge 52 opposite each other in the Y-axis direction.

[0042] 1, the resistor 5 is formed with a first trimming groove 11 and a second trimming groove 12 aligned in the X-axis direction. More specifically, the first trimming groove 11 is formed on the negative side of the resistor 5 along the X-axis, and the second trimming groove 12 is formed on the positive side of the resistor 5 along the X-axis.

[0043] Because the first trimming grooves 11 are formed in portions of the resistor 5 where the current density is relatively low, the effect of forming the first trimming grooves 11 on the resistance value of the resistor 5 is small. Therefore, the resistance value of the resistor 5 can be adjusted with high precision by adjusting the length and shape of the first trimming grooves 11. The second trimming grooves 12 are formed to adjust the resistance value of the resistor 5 by changing the current path in the resistor 5. Because a portion of the second trimming grooves 12 is formed in portions of the resistor 5 where the current density is higher than that of the first trimming grooves 11, the effect of forming the second trimming grooves 12 on the resistance value of the resistor 5 is greater than that of the first trimming grooves 11.

[0044] As shown in FIG. 1, the first trimming groove 11 has a first linear portion S1 and a second linear portion S2.

[0045] The first linear portion S1 is a linear groove that extends along the Y-axis direction from the first edge 51 toward the second edge 52 to the tip portion E1.

[0046] The second linear portion S2 is a linear groove that extends from the tip portion E1 of the first linear portion S1 along the X-axis direction toward the second trimming groove 12 to the tip portion E2. In other words, the second linear portion S2 is a linear groove that extends from the tip portion E1 toward the positive direction of the X-axis to the tip portion E2. The distance between the tip portion E1 and the first edge 51 in the Y-axis direction is approximately equal to the distance between the tip portion E2 of the second linear portion S2 and the first edge 51 in the Y-axis direction. In other words, the second linear portion S2 is approximately parallel to the first edge 51. In other words, the first trimming groove 11 is a substantially L-shaped groove that is open on the side facing the first edge 51.

[0047] As shown in FIG. 1, the second trimming groove 12 has a third linear portion S3 and a curved portion C1.

[0048] The third linear portion S3 is a linear groove that extends along the Y-axis direction from the first edge 51 toward the second edge 52 to the tip portion E3.

[0049] The curved portion C1 is a groove that extends from the tip portion E3 of the third straight portion S3 to the tip portion F1 toward the first trimming groove 11. More specifically, the curved portion C1 is a curved groove that is convex in the direction from the first edge 51 toward the second edge 52. In this embodiment, the curved portion C1 is an arc that is convex in the direction from the first edge 51 toward the second edge 52. In other words, in this embodiment, the curvature of the curved portion C1 is constant.

[0050] Furthermore, when the curved portion C1 is arc-shaped, the central angle of the curved portion C1 is preferably 160° or more. In this embodiment, the central angle of the curved portion C1 is 180°. That is, in this embodiment, the curved portion C1 is semicircular.

[0051] The tip portion E2 of the second straight portion S2 of the first trimming groove 11 and the tip portion F1 of the curved portion C1 of the second trimming groove 12 face each other in the X-axis direction. In other words, the distance in the Y-axis direction between the tip portion F1 of the curved portion C1 and the first edge 51 is approximately equal to the distance in the Y-axis direction between the tip portion E2 and the first edge 51.

[0052] As described above, the curved portion C1 has an arc shape that is convex in the direction from the first edge 51 to the second edge 52. That is, the apex P1 of the curved portion C1 is located closer to the second edge 52 than the tip F1 of the curved portion C1, the tip E2 of the second straight portion S2, and the tip E1 of the first straight portion S1. In other words, the tip E1 of the first straight portion S1 is located closer to the first edge 51 than the apex P1 of the curved portion C1. Here, the apex P1 is, for example, a portion of the curved portion C1 that has a certain range and includes the point (nearest point) closest to the second edge 52. For example, the apex P1 is a circular region whose diameter is the width dimension of the groove and that includes the nearest point on the outer periphery of the circular region.

[0053] (1-2-11) Effects The effects of the chip resistor 1 of this embodiment will be described below.

[0054] 3A shows the results of a simulation of the current density distribution when a predetermined DC voltage is applied to resistor 50 of the comparative example. FIG. 3B shows the results of a simulation of the temperature distribution when a predetermined DC voltage is applied to resistor 50. Resistor 50 differs from resistor 5 in that it includes third trimming grooves 13 having fourth linear portions S4 and fifth linear portions S5, instead of second trimming grooves 12 in resistor 5. Other than the above, resistor 50 shares a common configuration with resistor 5. The phrase "applying a predetermined DC voltage" used here refers to applying a predetermined DC voltage between first electrode 3 and second electrode 4 to which resistor 5 is connected.

[0055] The fourth linear portion S4 is a linear groove that extends from the first edge 51 toward the second edge 52 along the Y-axis direction.

[0056] The fifth linear portion S5 is a linear groove that extends from the tip E4 of the fourth linear portion S4 along the X-axis direction toward the first trimming groove 11. In other words, the fifth linear portion S5 is a linear groove that extends from the tip E4 of the fourth linear portion S4 toward the negative direction of the X-axis. The distance between the tip E4 and the first edge 51 in the Y-axis direction is approximately equal to the distance between the tip E5 of the fifth linear portion S5 and the first edge 51 in the Y-axis direction. In other words, the fifth linear portion S5 is approximately parallel to the first edge 51. In other words, the third trimming groove 13 is a substantially L-shaped groove that is open on the side facing the first edge 51.

[0057] The length in the Y-axis direction of the fourth straight line portion S4 is longer than the length in the Y-axis direction of the first straight line portion S1 of the first trimming groove 11. In other words, the fifth straight line portion S5 extending from the tip end portion E4 of the fourth straight line portion S4 is located closer to the second edge 52 than the first trimming groove 11 in the Y-axis direction.

[0058] 4A shows the results of a simulation of the current density distribution when a predetermined DC voltage is applied to the resistor 5 included in the chip resistor 1 of this embodiment. Also, FIG. 4B shows the results of a simulation of the temperature distribution when a predetermined DC voltage is applied to the resistor 5.

[0059] As shown in FIG. 3A , when a predetermined DC voltage is applied to the resistor 50 of the comparative example, the current density in the resistor 50 tends to increase toward the second edge 52 in the Y-axis direction. As a result, a locally high current density region occurs around the third trimming groove 13, which is located closer to the second edge 52 than the first trimming groove 11. More specifically, locally high current density regions (first portion H10 and second portion H20) occur near the tip portions E4 and E5 of the third trimming groove 13, which have larger curvatures than the other portions. As a result, locally high temperature regions (hot spots H1 and H2) occur in the resistor 50 at positions corresponding to the first portion H10 and the second portion H20, as shown in FIG. 3B . Simulation results indicate that the maximum temperature at the hot spots H1 and H2 is approximately 300°C.

[0060] As shown in FIG. 4A , even when a predetermined DC voltage is applied to resistor 5 of this embodiment, the current density tends to increase in the Y-axis direction toward second edge 52. However, in resistor 5, there is no locally high current density around the curved portion C1 of second trimming groove 12, which is located closer to second edge 52 than first trimming groove 11. This is likely because the curvature of curved portion C1 is greater than the curvature of tip portion E4 of fourth linear portion S4 and tip portion E5 of fifth linear portion S5, making it difficult for electric field concentration to occur in curved portion C1. As shown in FIG. 4B , resistor 5 has a hot spot H3 near vertex P1 of curved portion C1. However, simulation results show that the maximum temperature at hot spot H3 is approximately 280°C, which is lower than the maximum temperatures of hot spots H1 and H2, which are approximately 300°C. Therefore, resistor 5 is able to suppress changes in resistance due to temperature increases.

[0061] The second trimming groove 12 in the resistor 5 is formed, for example, by laser processing. During the process of forming the second trimming groove 12, microcracks occur around the tip portion F1 of the curved portion C1. Here, in the resistor 5, the curved portion C1 has an arc shape that is convex in the direction from the first edge 51 toward the second edge 52, and the curved portion C1 is formed so that the tip portion F1 faces the tip portion E2 of the second linear portion S2 of the first trimming groove 11 in the X-axis direction. As a result, the tip portion F1 of the curved portion C1 is located in a region where the current density is lower on the first edge 51 side than the vertex portion P1. This reduces the effect of microcracks occurring around the tip portion F1 on the resistance value of the resistor 5.

[0062] (1-2-12) Method for Manufacturing Chip Resistor Hereinafter, a method for manufacturing the chip resistor 1 will be described. However, for the sake of simplicity, only the formation of the first upper surface electrode 3, the second upper surface electrode 4, and the resistor 5 will be described.

[0063] First, an electrode paste is screen-printed on both ends in the X-axis direction of the surface 21 of the substrate 2, and then fired at 850° C. to form the first upper surface electrode 3 and the second upper surface electrode 4.

[0064] Next, a resistive paste is screen-printed between the first upper surface electrode 3 and the second upper surface electrode 4, and then fired at 850° C. to form the resistor 5.

[0065] Finally, the first trimming groove 11 and the second trimming groove 12 aligned in the X-axis direction are formed in the resistor 5 by laser processing.

[0066] That is, the manufacturing method of the chip resistor 1 includes an electrode forming process, a resistor forming process, and a trimming groove forming process. In the electrode forming process, a first upper surface electrode 3 and a second upper surface electrode 4 are formed on both ends of the surface 21 of the substrate 2 in the X-axis direction. In the resistor forming process, a resistor 5 is formed on the surface 21 between the first upper surface electrode 3 and the second upper surface electrode 4. In the trimming groove forming process, a first trimming groove 11 and a second trimming groove 12 aligned in the X-axis direction are formed in the resistor 5. The first trimming groove 11 has a first linear portion S1 and a second linear portion S2. The first linear portion S1 extends along the Y-axis direction from a first edge 51 of the resistor 5 in the Y-axis direction toward a second edge 52 of the resistor 5 in the Y-axis direction. The second linear portion S2 extends along the X-axis direction from a tip portion E1 of the first linear portion S1 toward the second trimming groove 12. The second trimming groove 12 has a third straight line portion S3 and a curved line portion C1. The third straight line portion S3 extends along the Y-axis direction from the first edge 51 toward the second edge 52. The curved line portion C1 extends from a tip end portion E3 of the third straight line portion S3 toward the first trimming groove 11. The curved line portion C1 is curved and convex in the direction from the first edge 51 toward the second edge 52.

[0067] (1-3) Modifications Each of the above-described embodiments is merely one of various embodiments of the present disclosure. The above-described embodiments can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Modifications of the above-described embodiments are listed below. The modifications described below can be applied in appropriate combinations.

[0068] The curved portion C1 of the second trimming groove 12 is not limited to an arc shape, and may be a curved portion that is convex in the direction from the first edge 51 to the second edge 52. For example, the curved portion C1 may be an ellipse, as shown in FIG.

[0069] The chip resistor 1 may be a thin film chip resistor.

[0070] (1-4) Aspects The present specification discloses the following aspects.

[0071] A chip resistor (1) according to a first aspect includes a substrate (2), a first electrode (3) and a second electrode (4) provided at both ends of one surface (21) of the substrate (2) in a first direction (X), and a resistor (5) provided between the first electrode (3) and the second electrode (4) on the one surface (21) of the substrate (2). The resistor (5) has a first trimming groove (11) and a second trimming groove (12) aligned in the first direction (X). The first trimming groove (11) has a first linear portion (S1) and a second linear portion (S2). The first linear portion (S1) extends along a second direction (Y) intersecting the first direction (X) from a first edge (51) of the resistor (5) in the second direction (Y) toward a second edge (52) opposite the first edge (51) of the resistor (5) in the second direction (Y) to a tip portion (E1). The second linear portion (S2) extends from the tip portion (E1) of the first linear portion (S1) along the first direction (X) toward the second trimming groove (12). The second trimming groove (12) has a third linear portion (S3) and a curved portion (C1). The third linear portion (S3) extends along the second direction (Y) from the first edge (51) of the resistor (5) toward the second edge (52) to a tip portion (E3). The curved portion (C1) extends from the tip portion (E3) of the third linear portion (S3) toward the first trimming groove (11). The curved portion (C1) is curved and convex in a direction from the first edge (51) toward the second edge (52) of the resistor (5).

[0072] According to this aspect, since the curved portion (C1) is curved in a convex shape extending from the first edge (51) to the second edge (52), electric field concentration is unlikely to occur and high-temperature areas (hot spots) are unlikely to occur even when the apex (P1) of the curved portion (C1) is formed in a region of high current density in the resistor (5). Therefore, according to this aspect, the shape of the curved portion (C1) of the second trimming groove (12) suppresses changes in the resistance value of the resistor (5) due to temperature increases, thereby improving the reliability of the chip resistor (1), while the resistance value of the resistor (5) can be adjusted with high precision by the first trimming groove (11).

[0073] In the chip resistor (1) according to the second aspect, in the first aspect, the tip portion (E2) of the second straight portion (S2) of the first trimming groove (11) and the tip portion (F1) of the curved portion (C1) of the second trimming groove (12) face each other in the first direction (X).

[0074] According to this aspect, the tip portion (F1) of the curved portion (C1) can be positioned in an area where the current density is low on the first edge (51) side, thereby reducing the effect of microcracks occurring around the tip portion (F1) on the resistance value of the resistor (5).

[0075] In the chip resistor (1) according to the third aspect, in the first or second aspect, the curved portion (C1) of the second trimming groove (12) has a vertex (P1) that is closest to the second edge (52) of the resistor (5). The tip portion (E1) of the first linear portion (S1) of the first trimming groove (11) is located closer to the first edge (51) than the vertex (P1) of the curved portion (C1) of the second trimming groove (12).

[0076] According to this aspect, the tip portion (F1) of the curved portion (C1) can be positioned in an area where the current density is low on the first edge (51) side, thereby reducing the effect of microcracks occurring around the tip portion (F1) on the resistance value of the resistor (5).

[0077] In the chip resistor (1) according to the fourth aspect, in any of the first to third aspects, the curved portion (C1) of the second trimming groove (12) is an arc-shaped portion that is convex in the direction from the first edge (51) of the resistor (5) toward the second edge (52).

[0078] According to this embodiment, the curved portion (C1) can be easily formed.

[0079] In the chip resistor (1) according to the fifth aspect, in the fourth aspect, the central angle of the curved portion (C1) of the second trimming groove (12) is 160° or more.

[0080] According to this aspect, the tip portion (F1) of the curved portion (C1) can be positioned in an area where the current density is low on the first edge (51) side, thereby reducing the effect of microcracks occurring around the tip portion (F1) on the resistance value of the resistor (5).

[0081] A manufacturing method for a chip resistor (1) according to a sixth aspect includes an electrode forming process, a resistor forming process, and a trimming groove forming process. In the electrode forming process, a first electrode (3) and a second electrode (4) are formed at both ends in a first direction (X) of one surface (21) of a substrate (2). In the resistor forming process, a resistor (5) is formed between the first electrode (3) and the second electrode (4) on the one surface (21). In the trimming groove forming process, a first trimming groove (11) and a second trimming groove (12) aligned in the first direction (X) are formed in the resistor (5). The first trimming groove (11) has a first linear portion (S1) and a second linear portion (S2). The first linear portion (S1) extends along a second direction (Y) intersecting the first direction (X) from a first edge (51) of the resistor (5) in the second direction (Y) toward a second edge (52) opposite the first edge (51) of the resistor (5) in the second direction (Y) to a tip portion (E1). The second linear portion (S2) extends from the tip portion (E1) of the first linear portion (S1) along the first direction (X) toward the second trimming groove (12). The second trimming groove (12) has a third linear portion (S3) and a curved portion (C1). The third linear portion (S3) extends along the second direction (Y) from the first edge (51) toward the second edge (52) to a tip portion (E3). The curved portion (C1) of the second trimming groove (12) extends from the tip portion (E3) of the third linear portion (S3) toward the first trimming groove (11). The curved portion (C1) is curved and convex in a direction from the first edge (51) toward the second edge (52).

[0082] According to this aspect, since the curved portion (C1) is curved in a direction from the first edge (51) to the second edge (52), electric field concentration is unlikely to occur and high-temperature areas (hot spots) are unlikely to occur even when the apex (P1) of the curved portion (C1) is formed in a region of high current density in the resistor (5). Therefore, according to this aspect, the curved portion (C1) of the second trimming groove (12) suppresses changes in the resistance value of the resistor (5) due to temperature increases, thereby improving the reliability of the chip resistor (1), while the resistance value of the resistor (5) can be adjusted with high precision by the first trimming groove (11).

[0083] (Embodiment 2) A chip resistor 101 according to embodiment 2 will be described below with reference to the drawings. The figures described in the following embodiments are schematic diagrams, and the ratios of the sizes and thicknesses of the components do not necessarily reflect the actual dimensional ratios. Furthermore, the configurations described in the following embodiments are merely examples of the present disclosure. The present disclosure is not limited to the following embodiments, and various modifications are possible depending on the design, etc., as long as the effects of the present disclosure can be achieved.

[0084] In the following description, the long side direction of the chip resistor 101 is referred to as the "X-axis direction," the short side direction of the chip resistor 101 as the "Y-axis direction," and the thickness direction of the chip resistor 101 as the "Z-axis direction." The X-axis, Y-axis, and Z-axis defining these directions are perpendicular to one another. Note that "perpendicular" in this disclosure is a concept that includes approximately perpendicular, and includes a range of 90°±10°. Furthermore, these directions are merely examples and are not intended to limit the directions in which the chip resistor 101 is used. Furthermore, the arrows indicating the "X-axis direction," "Y-axis direction," and "Z-axis direction" in the drawings are merely shown for the purpose of explanation and have no substance.

[0085] (2-1) Overview First, an overview of the chip resistor 101 according to this embodiment will be described.

[0086] As shown in Figures 6 and 7, the chip resistor 101 comprises a substrate 102, a first electrode (first upper surface electrode) 103 and a second electrode (second upper surface electrode) 104 respectively provided at both ends in a first direction (X-axis direction) of one surface (surface) 121 of the substrate 102, and a resistor 105 provided between the first electrode 103 and the second electrode 104 on the one surface 121 of the substrate 102.

[0087] Resistor 105 includes a serpentine portion 106, a first rectangular portion 107, and a second rectangular portion 108. Resistor 105 is formed with a first trimming groove 111, a second trimming groove 112, and a third trimming groove 113.

[0088] The first rectangular portion 107 is connected to the meandering portion 106 and the first electrode 103 .

[0089] The second rectangular portion 108 is connected to the serpentine portion 106 and the second electrode 104 .

[0090] The first trimming groove 111 is formed in the first rectangular portion 107 and extends along a second direction (Y-axis direction) that intersects the first direction from a first edge 151 of the resistor 105 in the second direction toward a second edge 152 of the resistor 105 in the second direction to a tip E101.

[0091] The second trimming groove 112 is formed in the second rectangular portion 108 and extends in the second direction from the second edge 152 toward the first edge 151 to the tip E102.

[0092] The third trimming groove 113 is formed in the first rectangular portion 107 between the first trimming groove 111 and the serpentine portion 106, and extends in the second direction from the first edge 151 toward the second edge 152 to the tip E103.

[0093] A tip E103 of third trimming groove 113 is located closer to first edge 151 than reference line L101. Reference line L101 connects tip E101 of first trimming groove 111 to intersection point P101. Intersection point P101 is the intersection point between first edge 151 and boundary line L102 between first rectangular portion 107 and serpentine portion 106.

[0094] Here, first trimming groove 111 and second trimming groove 112 are formed to adjust the resistance value of resistor 105 by lengthening the current path through which current flows in resistor 105. In addition, third trimming groove 113 is formed to minutely change the cross-sectional area of ​​the current path to adjust the resistance value of resistor 105 with high precision.

[0095] Furthermore, in the region between the first trimming groove 111 and the serpentine portion 106 in the first rectangular portion 107, it has been confirmed through simulation that the current density in the region closer to the first edge 151 than the reference line L101 is lower than in other regions when a predetermined voltage is applied between the first electrode 103 and the second electrode 104.

[0096] According to the above configuration, by forming the third trimming groove 113 so that the tip E103 is located closer to the first edge 151 than the reference line L101, it is possible to suppress a temperature rise in the tip E103 when a current flows through the resistor 105. This makes it possible to suppress a change in the resistance value of the resistor 105 due to a temperature rise in the tip E103. In other words, according to the above configuration, it is possible to adjust the resistance value of the resistor 105 with high precision while improving the reliability of the chip resistor 101.

[0097] (2-2) Details The chip resistor 101 according to this embodiment will be described in detail with reference to the drawings.

[0098] (2-2-1) Basic Configuration of Chip Resistor The chip resistor 101 is a chip resistor for surface mounting (SMT: Surface Mount Technology) that is mounted on the surface (mounting surface) of a printed circuit board using, for example, a surface mounter. In this embodiment, as an example, the chip resistor 101 is a thick-film chip resistor.

[0099] 6 and 7, the chip resistor 101 has a substrate 102, a first upper surface electrode 103, a second upper surface electrode 104, and a resistor 105. Also, as shown in Fig. 7, the chip resistor 101 further has a first lower surface electrode 133, a second lower surface electrode 134, a first end surface electrode 135, a second end surface electrode 136, a pair of first plating layers 137, and a pair of second plating layers 138. Furthermore, the chip resistor 101 has a glass protective film 141 and a resin protective film 142.

[0100] (2-2-2) Substrate The substrate 102 is an insulating substrate made of an insulator. For example, the substrate 102 is made of Al ２ O ３ It is composed of alumina containing 96% of

[0101] As an example, the substrate 102 is formed in a rectangular shape with its longitudinal direction along the X-axis direction (first direction), its lateral direction along the Y-axis direction (second direction), and its thickness direction along the Z-axis direction.

[0102] (2-2-3) Top Surface Electrode The first top surface electrode 103 and the second top surface electrode 104 are provided at opposite ends of the surface 121 of the substrate 102 in the X-axis direction. More specifically, the first top surface electrode 103 is provided at the end of the surface 121 facing the negative direction of the X-axis. The second top surface electrode 104 is provided at the end of the surface 121 facing the positive direction of the X-axis.

[0103] The first upper surface electrode 103 and the second upper surface electrode 104 are formed by printing a thick film material containing a metal such as silver as a main material on the surface 121 and then firing it.

[0104] (2-2-4) Lower Surface Electrode The first lower surface electrode 133 and the second lower surface electrode 134 are provided on opposite ends of the rear surface 122 of the substrate 102 in the X-axis direction. More specifically, the first lower surface electrode 133 is provided on the end of the rear surface 122 facing in the negative direction of the X-axis. The second lower surface electrode 134 is provided on the end of the rear surface 122 facing in the positive direction of the X-axis.

[0105] The first lower surface electrode 133 and the second lower surface electrode 134 are formed by printing a thick film material containing a metal such as silver as a main component on the rear surface 122 and then firing the printed material. The first lower surface electrode 133 and the second lower surface electrode 134 are provided at positions corresponding to the first upper surface electrode 103 and the second upper surface electrode 104, respectively, in the Z-axis direction.

[0106] (2-2-5) Side Electrodes The first end electrode 135 and the second end electrode 136 are provided on a pair of side surfaces 123 opposite each other in the X-axis direction of the substrate 102. More specifically, the first end electrode 135 is provided on the side surface 123 in the negative direction of the X-axis. The second end electrode 136 is provided on the side surface 123 in the positive direction of the X-axis.

[0107] The first end surface electrode 135 electrically connects the first upper surface electrode 103 and the first lower surface electrode 133. The second end surface electrode 136 electrically connects the second upper surface electrode 104 and the second lower surface electrode 134.

[0108] The first end surface electrode 135 and the second end surface electrode 136 are formed (deposited) by printing a material made of silver and synthetic resin on the pair of side surfaces 123 .

[0109] (2-2-6) First Plating Layer The pair of first plating layers 137 is made of, for example, nickel plating. The pair of first plating layers 137 covers the first end surface electrode 135 and the second end surface electrode 136, respectively, at both ends of the substrate 102 in the X-axis direction.

[0110] (2-2-7) Second Plating Layer The pair of second plating layers 138 is made of, for example, tin plating. The pair of second plating layers 138 covers the pair of first plating layers 137 at both ends of the substrate 102 in the X-axis direction, respectively.

[0111] (2-2-8) Glass Protective Film The glass protective film 141 is a film for protecting the resistor 105. As shown in FIG. 6 , the glass protective film 141 covers the entire resistor 105. The glass protective film 141 is made of, for example, lead oxide glass. The glass protective film 141 is formed (deposited) by, for example, screen printing. Note that the glass protective film 141 is not limited to lead oxide glass, and may be made of, for example, silicate glass.

[0112] (2-2-9) Resin Protective Film The resin protective film 142 is made of, for example, epoxy resin, and covers the entire glass protective film 141. The resin protective film 142 is formed (deposited) by, for example, applying epoxy resin by screen printing and then thermally curing the epoxy resin.

[0113] (2-2-10) Resistor (2-2-10-1) Overview of Resistor The resistor 105 is provided between the first upper surface electrode 103 and the second upper surface electrode 104 on the surface 121 (one surface) of the substrate 102. Opposite ends of the resistor 105 in the X-axis direction are connected to the first upper surface electrode 103 and the second upper surface electrode 104, respectively.

[0114] The resistor 105 is formed by printing a thick film material, for example, consisting of about 10 wt % lead ruthenate, about 53 wt % glass, and about 37 wt % solvent, on the surface 121 of the substrate 102 and then firing it. The resistor 105 is generally rectangular and has a first edge 151 and a second edge 152 opposite each other in the Y-axis direction.

[0115] As shown in FIG. 6, the resistor 105 has a meandering portion 106, a first rectangular portion 107, and a second rectangular portion 108.

[0116] (2-2-10-2) Meandering Section The meandering section 106 is provided in the center in the X-axis direction of the resistor 105. The meandering section 106 has a first recess 109 and a second recess 110.

[0117] The first recess 109 is disposed on the first upper surface electrode 103 side in the X-axis direction. The first recess 109 is a cutout that is connected to the second edge 152 and is open on the second edge 152 side. The first recess 109 extends along the Y-axis direction from the second edge 152 toward the first edge 151 of the resistor 105.

[0118] The second recess 110 is disposed on the second upper surface electrode 104 side in the X-axis direction. The second recess 110 is a cutout that is connected to the first edge 151 and is open on the first edge 151 side. The second recess 110 extends along the Y-axis direction from the first edge 151 toward the second edge 152. This gives the serpentine portion 106 a serpentine shape (approximately S-shape).

[0119] (2-2-10-3) First Rectangular Portion The first rectangular portion 107 is provided between the meandering portion 106 and the first upper surface electrode 103. The first rectangular portion 107 is formed in a rectangular shape.

[0120] The first rectangular portion 107 has an end portion in the negative direction of the X axis electrically connected to the first upper surface electrode 103. The first rectangular portion 107 has an end portion in the positive direction of the X axis electrically connected to the serpentine portion 106. In this embodiment, the first rectangular portion 107 and the serpentine portion 106 are integrally formed.

[0121] The first rectangular portion 107 has a first trimming groove 111 and a third trimming groove 113 formed therein.

[0122] The first trimming groove 111 is a linear groove that extends along the Y-axis direction from the first edge 151 of the resistor 105 toward the second edge 152 of the resistor 105 to the tip E101. In other words, the first trimming groove 111 is a groove that is connected to the first edge 151 and is open on the first edge 151 side.

[0123] Forming the first trimming groove 111 makes it possible to lengthen the current path in the first rectangular portion 107. More specifically, forming the first trimming groove 111 forms a path in the first rectangular portion 107 that extends along the Y-axis direction, lengthening the current path. This makes it possible to adjust the resistance value in the first rectangular portion 107.

[0124] As shown in FIG. 6, the third trimming groove 113 is formed between the first trimming groove 111 and the serpentine portion 106 .

[0125] The third trimming groove 113 is a linear groove that extends along the Y-axis direction from the first edge 151 toward the second edge 152 to the tip E103. In other words, the third trimming groove 113 is a groove that is connected to the first edge 151 and is open on the first edge 151 side. In this embodiment, the first trimming groove 111 and the third trimming groove 113 are formed to be parallel to each other. Furthermore, the first trimming groove 111 and the third trimming groove 113 are formed with a predetermined gap between them in the X-axis direction.

[0126] By forming third trimming groove 113, the cross-sectional area of ​​the current path in first rectangular portion 107 can be minutely changed, and the resistance value in first rectangular portion 107 can be adjusted with high precision.

[0127] As shown in FIG. 6 , the third trimming groove 113 is formed such that a tip E103 of the third trimming groove 113 is located closer to the first edge 151 than the reference line L101. Here, the reference line L101 is an imaginary straight line connecting the tip E101 of the first trimming groove 113 to an intersection point P101. The intersection point P101 is the intersection point between the boundary line L102 between the first rectangular portion 107 and the serpentine portion 106 and the first edge 151. In this embodiment, the tip E103 of the third trimming groove 113 refers to the point in the third trimming groove 113 that is closest to the second edge 152. The tip E103 may be a portion of the third trimming groove 113 that includes a certain range that includes the point closest to the second edge 152. In this embodiment, the tip E101 of the first trimming groove 111 refers to the point in the first trimming groove 111 that is closest to the second edge 152. Note that the tip E101 may be a portion in the first trimming groove 111 that includes a certain range that includes the point that is closest to the second edge 152.

[0128] (2-2-10-4) Second Rectangular Portion The second rectangular portion 108 is provided between the meandering portion 106 and the second upper surface electrode 104. The second rectangular portion 108 is formed in a rectangular shape.

[0129] The second rectangular portion 108 has an end portion in the positive direction of the X axis electrically connected to the second upper surface electrode 104. In addition, the second rectangular portion 108 has an end portion in the negative direction of the X axis mechanically and electrically connected to the serpentine portion 106. In this embodiment, the second rectangular portion 108 and the serpentine portion 106 are integrally formed.

[0130] A second trimming groove 112 is formed in the second rectangular portion 108. The second trimming groove 112 is a linear groove that extends along the Y-axis direction from the second edge 152 toward the first edge 151 to the tip E102. In other words, the second trimming groove 112 is a groove that is connected to the second edge 152 and is open on the second edge 152 side.

[0131] Forming the second trimming groove 112 makes it possible to lengthen the current path in the second rectangular portion 108. More specifically, forming the second trimming groove 112 forms a path in the second rectangular portion 108 that extends along the Y-axis direction, lengthening the current path. This makes it possible to adjust the resistance value in the second rectangular portion 108.

[0132] In this embodiment, the first trimming groove 111 and the second trimming groove 112 are, for example, point-symmetric with each other, which allows the resistance value of the first rectangular portion 107 of the resistor 105 and the resistance value of the second rectangular portion 108 of the resistor 105 to be closer to each other.

[0133] (2-2-11) Effects The effects of the chip resistor 101 of this embodiment will be described below with reference to FIGS.

[0134] 8 shows the results of a simulation of the temperature distribution when a predetermined DC voltage is applied to the resistor 105 (105A) included in the chip resistor 101 of this embodiment. Note that "application of a predetermined DC voltage" here refers to application of a predetermined DC voltage between the first upper surface electrode 103 and the second upper surface electrode 104.

[0135] In resistor 105A, third trimming groove 113 is formed so that tip E103 is located closer to first edge 151 than reference line L101. Fig. 9 shows the results of a simulation of temperature distribution when a predetermined DC voltage is applied to resistor 105B, a comparative example. Resistor 105B differs from resistor 105A in that third trimming groove 113 is formed so that tip E103 is located closer to second edge 152 than reference line L101.

[0136] 8 and 9, the temperature rise at the tip E103 of the resistor 105A is suppressed compared to that at the resistor 105B. Specifically, a high-temperature portion (hot spot H101) appears around the tip E103 of the resistor 105B, whereas the hot spot H101 does not appear around the tip E103 of the resistor 105A. This makes it possible to suppress changes in the resistance value of the resistor 105A due to the occurrence of the hot spot H101.

[0137] FIG. 10 shows the results of a simulation of the temperature distribution when a predetermined DC voltage is applied to a resistor 105 (105C) having a third trimming groove 113 formed at a different position from that of the resistor 105A. In the resistor 105C, the third trimming groove 113 is formed further toward the positive side of the X axis than the resistor 105A. In the resistor 105C, the third trimming groove 113 is also formed so that the tip E103 is located closer to the first edge 151 than the reference line L101. FIG. 11 shows the results of a simulation of the temperature distribution when a predetermined DC voltage is applied to a comparative resistor 105D. The resistor 105D differs from the resistor 105C in that the third trimming groove 113 is formed so that the tip E103 is located closer to the second edge 152 than the reference line L101.

[0138] 10 and 11 , the temperature rise of the tip E103 of the resistor 105C is suppressed compared to that of the resistor 105D. Specifically, a hot spot H101 appears around the tip E103 of the resistor 105D, whereas a hot spot H101 does not appear around the tip E103 of the resistor 105C. This makes it possible to suppress a change in the resistance value of the resistor 105C due to the occurrence of the hot spot H101.

[0139] The third trimming groove 113 is formed by, for example, laser processing. During the process of forming the third trimming groove 113, microcracks occur at the tip E103 of the third trimming groove 113. Here, in the resistor 105 (105A, 105C), the third trimming groove 113 is formed so that the tip E103 is located closer to the first edge 151 than the reference line L101, so that the microcracks at the tip E103 are located in a portion with low current density. This makes it possible to suppress changes in the resistance value of the resistor 105 due to microcracks.

[0140] (2-2-12) Method for Manufacturing Chip Resistor Hereinafter, a method for manufacturing the chip resistor 101 will be described. However, for the sake of simplicity, only the formation of the first upper surface electrode 103, the second upper surface electrode 104, and the resistor 105 will be described.

[0141] First, an electrode paste is screen-printed on both ends in the X-axis direction of surface 121 of substrate 102, and then fired at 850° C. to form first upper surface electrode 103 and second upper surface electrode 104.

[0142] Next, a resistive paste is screen-printed between the first upper surface electrode 103 and the second upper surface electrode 104, and then fired at 850° C. to form the serpentine portion 106, the first rectangular portion 107, and the second rectangular portion 108.

[0143] Finally, first trimming groove 111 and third trimming groove 113 are formed in first rectangular portion 107, and second trimming groove 112 is formed in second rectangular portion 108 by laser processing.

[0144] That is, the manufacturing method of chip resistor 101 includes an electrode forming process of forming first upper surface electrode 103 and second upper surface electrode 104 on both ends in the X-axis direction of surface 121 of substrate 102, and a resistor forming process of forming resistor 105 between first upper surface electrode 103 and second upper surface electrode 104 on surface 121. The resistor forming process includes a first process, a second process, a third process, and a fourth process. In the first process, serpentine portion 106, a first rectangular portion 107 connected to serpentine portion 106 and first upper surface electrode 103, and a second rectangular portion 108 connected to serpentine portion 106 and second upper surface electrode 104 are formed on surface 121 of substrate 102. In a second step, a first trimming groove 111 is formed in the first rectangular portion 107 along the Y-axis direction, extending from a first edge 151 of the resistor 105 in the Y-axis direction toward a second edge 152 opposite the first edge 151 to the tip E101. In a third step, a second trimming groove 112 is formed in the second rectangular portion 108 along the Y-axis direction, extending from the second edge 152 toward the first edge 151 to the tip E102. The first trimming groove 111 and the second trimming groove 112 are formed so that the resistance value of the chip resistor 101 roughly approaches the desired resistance value. In a fourth step, a third trimming groove 113 is formed in the first rectangular portion 107 between the first trimming groove 111 and the serpentine portion 106, extending from the first edge 151 of the resistor 105 toward the second edge 152 to the tip E103 along the Y-axis direction. The third trimming groove 113 is formed so that the resistance value of the chip resistor 101 approaches the desired resistance value with high precision. As described above, the third trimming groove 113 is provided so that the tip E103 of the third trimming groove 113 is located closer to the first edge 151 than the reference line L101. Here, the reference line L101 is an imaginary straight line connecting the tip E101 of the first trimming groove 111 and an intersection point P101. The intersection point P101 is the intersection point between the boundary line L102 between the first rectangular portion 107 and the serpentine portion 106 and the first edge 151.

[0145] (2-3) Modifications Each of the above-described embodiments is merely one of various embodiments of the present disclosure. The above-described embodiments can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Modifications of the above-described embodiments are listed below. The modifications described below can be applied in appropriate combinations.

[0146] (2-3-1) Modification 101 The resistor 105 may further include a fourth trimming groove 114 as shown in FIG.

[0147] The fourth trimming groove 114 is formed in the second rectangular portion 108 between the second trimming groove 112 and the serpentine portion 106. The fourth trimming groove 114 extends along the Y-axis direction from the second edge 152 of the resistor 105 toward the first edge 151 to the tip E104.

[0148] The fourth trimming groove 114 is a groove that is connected to the second edge 152 and is open on the side of the second edge 152. The second trimming groove 112 and the fourth trimming groove 114 are formed to be parallel to each other.

[0149] By forming the fourth trimming groove 114, the cross-sectional area of ​​the current path in the second rectangular portion 108 can be minutely changed, and the resistance value in the second rectangular portion 108 can be adjusted with high precision.

[0150] The third trimming groove 113 and the fourth trimming groove 114 are, for example, point-symmetric with each other, which allows the resistance value of the first rectangular portion 107 of the resistor 105 and the resistance value of the second rectangular portion 108 of the resistor 105 to be closer to each other.

[0151] The tip E104 of the fourth trimming groove 114 is located closer to the second edge 152 than the reference line L110. The reference line L110 is a straight line connecting the tip E102 of the second trimming groove 112 to an intersection point P110. The intersection point P110 is the intersection point of the boundary line L120 between the second rectangular portion 108 and the serpentine portion 106 and the second edge 152. The tip E104 of the fourth trimming groove 114 indicates the point in the fourth trimming groove 114 that is closest to the first edge 151. The tip E104 may be a portion of the fourth trimming groove 114 that includes a certain range including the point closest to the first edge 151. In this embodiment, the tip E102 of the second trimming groove 112 indicates the point in the second trimming groove 112 that is closest to the first edge 151. The tip E102 may be a portion of the second trimming groove 112 that includes a certain range including the point closest to the first edge 151.

[0152] Furthermore, simulations have confirmed that in the region between the second trimming groove 112 and the serpentine portion 106 in the second rectangular portion 108, the current density is lower in the region closer to the second edge 152 than in other portions of the region closer to the reference line L110.

[0153] By forming the fourth trimming groove 114 so that the tip E104 is located closer to the second edge 152 than the reference line L110, it is possible to suppress a temperature rise at the tip E104 when a current flows through the resistor 105. This makes it possible to suppress a change in the resistance value of the resistor 105 due to a temperature rise at the tip E104.

[0154] Furthermore, the fourth trimming groove 114 is formed by, for example, laser processing. During the process of forming the fourth trimming groove 114, microcracks occur at the tip E104 of the fourth trimming groove 114. Here, by forming the fourth trimming groove 114 so that the tip E104 is located closer to the second edge 152 than the reference line L110, the microcracks at the tip E104 can be located in an area with low current density, and changes in the resistance value of the resistor 105 due to the microcracks can be suppressed.

[0155] (2-3-2) Modification 102 In the above embodiment, first trimming groove 111 and third trimming groove 113 are formed with a predetermined distance between them in the X-axis direction, but first trimming groove 111 and third trimming groove 113 may also be formed without any distance between them in the X-axis direction. That is, as shown in FIG. 13 , first trimming groove 111 and third trimming groove 113 may be formed so that at least a portion of them overlaps or connects with each other. This allows the cross-sectional area of ​​the current path in first rectangular portion 107 to be changed even more minutely, thereby enabling the resistance value in first rectangular portion 107 to be adjusted with even greater precision.

[0156] (2-3-3) Other Modifications The chip resistor 101 may be a thin film chip resistor.

[0157] In the resistor 105, a plurality of third trimming grooves 113 may be formed.

[0158] (2-4) Aspects The present specification discloses the following aspects.

[0159] A chip resistor (101) according to a seventh aspect includes a substrate (102), a first electrode (103) and a second electrode (104) provided at both ends of one surface (121) of the substrate (102) in a first direction (X), and a resistor (105) provided between the first electrode (103) and the second electrode (104) on the one surface (121) of the substrate (102). The resistor (105) includes a serpentine portion (106), a first rectangular portion (107), a second rectangular portion (108), a first trimming groove (111), a second trimming groove (112), and a third trimming groove (113). The first rectangular portion (107) is connected to the serpentine portion (106) and the first electrode (103). The second rectangular portion (108) is connected to the serpentine portion (106) and the second electrode (104). The first trimming groove (111) is formed in the first rectangular portion (107) and extends along a second direction (Y) intersecting the first direction (X) from a first edge (151) of the resistor (105) in the second direction (Y) to a second edge (152) of the resistor (105) in the second direction (Y). The second trimming groove (112) is formed in the second rectangular portion (108) and extends along the second direction (Y) from the second edge (152) to the first edge (151). The third trimming groove (113) is formed in the first rectangular portion (107) between the first trimming groove (111) and the serpentine portion (106) and extends from the first edge (151) to the second edge (152) along the second direction (Y). The tip (E103) of the third trimming groove (113) is located closer to the first edge (151) than the reference line (L101). The reference line (L101) connects the tip (E101) of the first trimming groove (111) to an intersection (P101). The intersection (P101) is the intersection point between the boundary line (L102) between the first rectangular portion (107) and the serpentine portion (106) and the first edge (151).

[0160] According to this aspect, it is possible to suppress the temperature rise of the tip (E103) when a current flows through the resistor (105). This makes it possible to suppress changes in the resistance value of the resistor (105) due to temperature rise of the tip (E103). Furthermore, it is possible to position microcracks in the tip (E103) in areas with low current density, thereby suppressing changes in the resistance value of the resistor (105) due to microcracks. In other words, according to this aspect, it is possible to adjust the resistance value of the resistor (105) with high precision while improving the reliability of the chip resistor (101).

[0161] In a chip resistor (101) according to an eighth aspect, in the seventh aspect, the resistor (105) further includes a fourth trimming groove (114). The fourth trimming groove (114) is formed in the second rectangular portion (108) between the second trimming groove (112) and the serpentine portion (106). The fourth trimming groove (114) extends along the second direction (Y) from the second edge (152) toward the first edge (151). The tip (E104) of the fourth trimming groove (114) is located closer to the second edge (152) than the reference line (L110). The reference line (L110) is a straight line connecting the tip (E102) of the second trimming groove (112) and the intersection point (P110). The intersection point (P110) is the intersection point between the boundary line (L120) between the second rectangular portion (108) and the serpentine portion (106) and the second edge (152).

[0162] According to this aspect, it is possible to suppress the temperature rise of the tip (E104) when a current flows through the resistor (105). This makes it possible to suppress changes in the resistance value of the resistor (105) due to temperature rise at the tip (E103). Furthermore, it is possible to position microcracks at the tip (E104) in areas with low current density, thereby suppressing changes in the resistance value of the resistor (105) due to microcracks. In other words, according to this aspect, it is possible to improve the reliability of the chip resistor (101) while adjusting the resistance value of the resistor (105) with high precision.

[0163] In the chip resistor (101) according to the ninth aspect, in the seventh or eighth aspect, the first trimming groove (111) and the third trimming groove (113) at least partially overlap each other.

[0164] According to this aspect, the cross-sectional area of ​​the current path in the first rectangular portion (107) can be changed more minutely, and the resistance value in the first rectangular portion (107) can be adjusted with even higher precision.

[0165] A manufacturing method for a chip resistor (101) according to a tenth aspect includes an electrode forming process for forming a first electrode (103) and a second electrode (104) at both ends in a first direction (X) of one surface (121) of a substrate (102), and a resistor forming process for forming a resistor (105) between the first electrode (103) and the second electrode (104) on the one surface (121). The resistor forming process includes a first process, a second process, a third process, and a fourth process. In the first process, a serpentine portion (106), a first rectangular portion (107) connected to the serpentine portion (106) and the first electrode (103), and a second rectangular portion (108) connected to the serpentine portion (106) and the second electrode (104) are formed. In a second step, a first trimming groove (111) is formed in the first rectangular portion (107) along a second direction (Y) intersecting the first direction (X), extending from a first edge (151) of the resistor (105) in the second direction (Y) toward a second edge (152) of the resistor (105) in the second direction (Y). In a third step, a second trimming groove (112) is formed in the second rectangular portion (108) along the second direction (Y) from the second edge (152) toward the first edge (151). In a fourth step, a third trimming groove (113) is formed in the first rectangular portion (107) between the first trimming groove (111) and the serpentine portion (106), extending from the first edge (151) toward the second edge (152) along the second direction (Y). The tip (E103) of the third trimming groove (113) is located closer to the first edge (151) than the reference line (L101). The reference line (L101) is an imaginary straight line connecting the tip (E101) of the first trimming groove (111) and the intersection point (P101). The intersection point (P101) is the intersection point between the boundary line (L102) between the first rectangular portion (107) and the serpentine portion (106) and the first edge (151).

[0166] According to this aspect, it is possible to suppress the temperature rise of the tip (E103) when a current flows through the resistor (105). This makes it possible to suppress changes in the resistance value of the resistor (105) due to temperature rise of the tip (E103). Furthermore, it is possible to position microcracks in the tip (E103) in areas with low current density, thereby suppressing changes in the resistance value of the resistor (105) due to microcracks. In other words, according to this aspect, it is possible to adjust the resistance value of the resistor (105) with high precision while improving the reliability of the chip resistor (101).

[0167] 1 Chip resistor 2 Substrate 3 First electrode 4 Second electrode 5 Resistor 11 First trimming groove 12 Second trimming groove 21 One surface 51 First edge 52 Second edge C1 Curved portion E1 Tip portion E2 Tip portion E3 Tip portion F1 Tip portion P1 Vertex portion S1 First straight portion S2 Second straight portion S3 Third straight portion 101 Chip resistor 102 Substrate 103 First electrode 104 Second electrode 105 Resistor 106 Serpentine portion 107 First rectangular portion 108 Second rectangular portion 111 First trimming groove 112 Second trimming groove 113 Third trimming groove 114 Fourth trimming groove 151 First edge 152 Second edge E101 Tip E102 Tip E103 Tip E104 Tip L101 Reference line L110 Reference line L102 Boundary line L120 Boundary line P101 Intersection P110 Intersection

Claims

1. A device comprising: a substrate; a first electrode and a second electrode provided at both ends in a first direction on one surface of the substrate; and a resistor provided between the first electrode and the second electrode on the one surface of the substrate, wherein the resistor has a first trimming groove and a second trimming groove formed in the first direction, the first trimming groove having: a first linear portion extending along a second direction intersecting the first direction from a first edge of the resistor in the second direction to a tip portion toward a second edge of the resistor opposite the first edge in the second direction; and a second linear portion extending from the tip portion of the first linear portion along the first direction toward the second trimming groove, and the second trimming groove having: a third linear portion extending along the second direction from the first edge of the resistor toward the second edge to a tip portion a curved portion extending from the tip portion of the third linear portion toward the tip portion of the first trimming groove and convex in a direction from the first edge toward the second edge of the resistor element.

2. The chip resistor according to claim 1, wherein the tip portion of the second straight portion of the first trimming groove and the tip portion of the curved portion of the second trimming groove face each other in the first direction.

3. A chip resistor as described in claim 1 or 2, wherein the curved portion of the second trimming groove has a vertex portion that is closest to the second edge of the resistor in the curved portion, and the tip portion of the first straight portion of the first trimming groove is located closer to the first edge than the vertex portion of the curved portion of the second trimming groove.

4. The chip resistor according to claim 1 or 2, wherein the curved portion of the second trimming groove is an arcuate shape that is convex in a direction from the first edge toward the second edge of the resistor element.

5. The chip resistor according to claim 4, wherein the central angle of the curved portion of the second trimming groove is 160° or greater.

6. A method for manufacturing a substrate, comprising the steps of: forming a first electrode and a second electrode at both ends in a first direction on one surface of the substrate; forming a resistor between the first electrode and the second electrode on the one surface of the substrate; and forming a first trimming groove and a second trimming groove aligned in the first direction in the resistor, wherein the first trimming groove has: a first linear portion extending along a second direction intersecting the first direction from a first edge of the resistor in the second direction to a tip portion toward a second edge opposite the first edge of the resistor in the second direction; and a second linear portion extending from the tip portion of the first linear portion along the first direction toward the second trimming groove; and a curved portion extending from the tip portion of the third straight portion toward the first trimming groove and convex in a direction from the first edge toward the second edge of the resistor element.

7. A device comprising: a substrate; a first electrode and a second electrode provided at both ends of one surface of the substrate in a first direction, respectively; and a resistor provided between the first electrode and the second electrode on the one surface of the substrate, wherein the resistor comprises: a serpentine portion; a first rectangular portion connected to the serpentine portion and the first electrode; and a second rectangular portion connected to the serpentine portion and the second electrode, wherein the first rectangular portion is formed with a first trimming groove extending along a second direction intersecting the first direction from a first edge of the resistor in the second direction to a tip thereof toward a second edge opposite to the first edge of the resistor in the second direction, and the second rectangular portion is formed with a second trimming groove extending along the second direction from the second edge of the resistor toward the first edge to a tip thereof, and a third trimming groove formed in the first rectangular portion between the first trimming groove and the serpentine portion of the resistor, and extending along the second direction from the first edge toward the second edge to a tip thereof, a tip end of the third trimming groove located closer to the first edge than a reference line connecting the tip end of the first trimming groove and an intersection of the boundary line between the first rectangular portion and the serpentine portion and the first edge.

8. The chip resistor described in claim 7, wherein the resistor further comprises a fourth trimming groove formed in the second rectangular portion between the second trimming groove and the serpentine portion and extending along the second direction from the second edge toward the first edge to a tip thereof, and the tip of the fourth trimming groove is located on the second edge side of a reference line connecting the intersection of the boundary line between the second rectangular portion and the serpentine portion of the resistor and the second edge to the tip of the second trimming groove.

9. The chip resistor according to claim 7 or 8, wherein the first trimming groove and the third trimming groove at least partially overlap each other.

10. A method for manufacturing a semiconductor device, comprising the steps of: forming a first electrode and a second electrode on both ends of one surface of a substrate in a first direction; and forming a resistor between the first electrode and the second electrode on the one surface of the substrate, wherein the step of forming the resistor comprises the steps of: forming a serpentine portion, a first rectangular portion connected to the serpentine portion and the first electrode, and a second rectangular portion connected to the serpentine portion and the second electrode on the one surface of the substrate; forming a first trimming groove in the first rectangular portion along a second direction intersecting the first direction, the first trimming groove extending from a first edge of the resistor in the second direction to a tip toward a second edge opposite the first edge of the resistor in the second direction; and forming a second trimming groove in the second rectangular portion along the second direction, the second trimming groove extending from the second edge toward the first edge to a tip. forming a third trimming groove in the first rectangular portion between the first trimming groove and the serpentine portion, the third trimming groove extending along the second direction from the first edge toward the second edge to a tip thereof, wherein the tip of the third trimming groove is located on the first edge side of a reference line connecting the tip of the first trimming groove and an intersection of the boundary line between the first rectangular portion and the serpentine portion and the first edge.

Images