JP6171500B2 - fuse - Google Patents

Description

  The present invention relates to a fuse.

  Conventionally, an attempt has been made to connect a fuse to an electronic component to protect the electronic component from an overcurrent. For example, in Patent Document 1, as an example of a fuse, first and second electrode portions disposed on an insulating substrate, a metal wiring portion that connects the first electrode portion and the second electrode portion, and A fuse including a low melting point metal part disposed on a part of a metal wiring part is described.

JP 2012-18777 A

  However, the fuse described in Patent Document 1 has a problem that the metal wiring part is hardly melted, that is, the overcurrent cannot be reliably interrupted.

  The objective of this invention is providing the fuse which can interrupt | block an overcurrent reliably.

  The fuse according to the present invention includes an insulating substrate, wiring, and a low melting point metal part. The wiring is arranged on one main surface of the insulating substrate. The low melting point metal part is provided on the wiring. The low melting point metal part has a melting point lower than that of the wiring, and dissolves the wiring when it becomes a melt. The surface on which the low melting point metal part is provided has a bank portion which is located outside the part on which the low melting point metal part is provided and protrudes from the lowest part among the parts on which the low melting point metal part is provided.

  In another specific aspect of the fuse according to the present invention, the bank portion is provided across the wiring outside the portion where the low melting point metal portion is provided.

  In another specific aspect of the fuse according to the present invention, the entire low melting point metal portion is provided inside the bank portion.

  In still another specific aspect of the fuse according to the present invention, the fuse further includes an insulating layer for constituting the bank portion. The insulating layer is provided between the insulating substrate and the wiring. The surface of the part located under the low melting point metal part of the wiring is located at a position lower than the surface of the part where the bank part of the wiring is provided.

  In still another specific aspect of the fuse according to the present invention, the fuse further includes an insulating layer for constituting the bank portion. The insulating layer is provided on the wiring.

  In another specific aspect of the fuse according to the present invention, the insulating layer repels a melt of a low melting point metal.

  In another specific aspect of the fuse according to the present invention, when the low melting point metal portion is melted and a melt of the low melting point metal is generated in the portion located in the region where at least the wiring of the insulating layer is provided, It is provided so as not to disappear due to the melt of the low melting point metal.

  In still another specific aspect of the fuse according to the present invention, at least a portion of the insulating layer located in a region where the wiring is provided is provided so as not to contact the melt of the low melting point metal.

  In still another specific aspect of the fuse according to the present invention, the fuse further includes a heating element for heating the low melting point metal part.

  In still another specific aspect of the fuse according to the present invention, the low-melting point metal portion contains Sn as a main component.

  ADVANTAGE OF THE INVENTION According to this invention, the fuse which can interrupt | block an overcurrent reliably can be provided.

1 is a schematic plan view of a fuse in an embodiment of the present invention. 1 is a schematic back view of a fuse in an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG. 1. FIG. 5 is a schematic cross-sectional view taken along line VV in FIG. 1. It is a schematic plan view for demonstrating the shape of the 1st electrode layer and heat generating body in one Embodiment of this invention. It is a schematic plan view for demonstrating the manufacturing process of the fuse in one Embodiment of this invention. It is a schematic plan view for demonstrating the manufacturing process of the fuse in one Embodiment of this invention. It is a schematic plan view for demonstrating the manufacturing process of the fuse in one Embodiment of this invention. It is a schematic plan view for demonstrating the manufacturing process of the fuse in one Embodiment of this invention. 1 is a schematic circuit diagram of a fuse in an embodiment of the present invention.

  Hereinafter, an example of the preferable form which implemented this invention is demonstrated. However, the following embodiment is merely an example. The present invention is not limited to the following embodiments.

  Moreover, in each drawing referred in embodiment etc., the member which has a substantially the same function shall be referred with the same code | symbol. The drawings referred to in the embodiments and the like are schematically described. A ratio of dimensions of an object drawn in a drawing may be different from a ratio of dimensions of an actual object. The dimensional ratio of the object may be different between the drawings. The specific dimensional ratio of the object should be determined in consideration of the following description.

  FIG. 1 is a schematic plan view of a fuse in the present embodiment. FIG. 2 is a schematic rear view of the fuse in the present embodiment. 3 is a schematic cross-sectional view taken along line III-III in FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a schematic cross-sectional view taken along line VV in FIG. 6 to 10 are schematic plan views for explaining the manufacturing process of the fuse of this embodiment. 6 to 10, the laminated structure is completed, and the fuse of this embodiment is obtained. FIG. 11 is a schematic circuit diagram of the fuse in the present embodiment.

  As shown in FIG. 11, the fuse 1 has a wiring 13 connected between the first terminal 11 and the second terminal 12. In the wiring 13, fuse electrode portions 13a and 13b are connected in series. Here, the fuse electrode portions 13a and 13b are blown when an overcurrent flows through the fuse 1 or when a signal for causing the fuse function to be developed is input to the fuse 1, and the first terminal 11 and the second terminal 12 is an insulating part. For example, when an overcurrent flows between the first terminal 11 and the second terminal 12, at least one of the fuse electrode portions 13a and 13b is melted. Thereby, the 1st terminal 11 and the 2nd terminal 12 are insulated. Therefore, the fuse 1 functions as a passive element that detects an overcurrent and automatically disconnects the wiring 13.

  A connection point 13 c between the fuse electrode portion 13 a and the fuse electrode portion 13 b is connected to the fourth terminal 16. A heating element 15 made of a resistor is provided between the third terminal 14 and the connection point 13c. The heating element 15 generates heat when electric power is applied between the third terminal 14 and at least one of the first and second terminals 11 and 12. Thereby, at least one of the fuse electrode portion 13a and the fuse electrode portion 13b is melted, and the first terminal 11 and the second terminal 12 are insulated. Therefore, the fuse 1 also functions as an active element that detects an overcurrent and actively cuts the wiring 13. The fuse according to the present invention may function only as a passive element or may function only as an active element.

  Next, a specific configuration of the fuse 1 will be described in detail with reference to FIGS.

  As shown in FIGS. 1 to 5, the fuse 1 includes an insulating substrate 20. The insulating substrate 20 can be configured by a ceramic substrate such as an alumina substrate, a resin substrate, or the like, for example. The insulating substrate 20 may be a multilayer substrate having wiring inside.

  The insulating substrate 20 has a first main surface 20a and a second main surface 20b. As shown in FIG. 2, first to fourth terminals 11, 12, 14, and 16 are disposed on the second main surface 20 b. The fourth terminal 16 is connected to a connection point between the heating element 15 and the connection point 13c shown in FIG. The first to fourth terminals 11, 12, 14, and 16 can be made of an appropriate conductive material such as Ag, AgPt, AgPd, or Cu. The thickness of the first to fourth terminals 11, 12, 14, and 16 can be, for example, about 10 μm to 20 μm.

  As shown in FIGS. 1 and 6, electrodes 21 to 24 are provided on the first main surface 20 a. The electrode 21 is connected to the first terminal 11 by a side electrode 25 and a via hole electrode 26 (see FIG. 2). The electrode 22 is connected to the second terminal 12 by a side electrode 27 and a via hole electrode 28. The electrode 23 is connected to the third terminal 14 by a side electrode 29. The electrode 24 is connected to the fourth terminal 16 by a side electrode 30. Each of the electrodes 21 to 24 can be made of an appropriate conductive material such as Ag, AgPt, AgPd, or Cu.

As shown in FIG. 6, the heating element 15 connected between the electrode 23 and the electrode 24 is provided on the main surface 20a. The electrode 23 and the heating element 15 are connected by a wiring 31. The electrode 24 and the heating element 15 are connected by a wiring 32. The heating element 15 is supported by the insulating substrate 20. Incidentally, the heating element 15, for _example, can be constituted by a resistive heating element consisting of RuO 2, AgPd, or the like.

  An electrode layer 35 (see FIGS. 3 to 5) is provided on the electrodes 23 and 24, the heating element 15, and the wirings 31 and 32. An insulating layer 36 is disposed between the electrode layer 35 and the electrodes 23 and 24 and the wirings 31 and 32. As shown in FIGS. 4, 5, and 7, in this embodiment, the insulating layer 36 is provided over the entire portion where the wirings 31 and 32 and the low melting point metal parts 41 and 42 overlap. However, in the present invention, for example, an opening or the like is formed in the insulating layer, and the wiring and the low melting point metal part may be connected to such an extent that the electrical resistance of the wiring does not decrease too much as a whole. As shown in FIGS. 3, 5, and 7, the insulating layer 36 is provided with a through hole 36 a. The through hole 36a is connected to each of the heating element 15 and the wiring 13 (specifically, the connection point 13c). The through hole 36a may be provided with a substantially constant diameter in the direction in which the central axis extends, or may be provided in a tapered shape. The through hole 36a may be provided in a tapered shape that tapers toward the insulating substrate 20 side, for example. In addition, the thickness of the insulating layer 36 can be about 15 micrometers-30 micrometers, for example.

  As shown in FIGS. 5 and 10, the electrode layer 35 includes a wiring 13 that connects the electrode 21 and the electrode 22. The wiring 13 includes a fuse electrode portion 13a and a fuse electrode portion 13b. A connection point 13c between the fuse electrode portion 13a and the fuse electrode portion 13b and the electrode 24 are connected by an electrode 37 shown in FIGS. The connection point 13c is connected to the heating element 15 through a high thermal conductor 38 disposed in the through hole 36a. The thermal conductivity of the high thermal conductor 38 is higher than the thermal conductivity of the insulating layer 36. The high thermal conductor 38 can be made of, for example, a metal. In the present embodiment, the high thermal conductor 38 and the wiring 13 are integrally provided. In this case, the high thermal conductor 38 can be easily provided.

  In addition, the thickness of the electrode layer 35 can be about 5 micrometers-20 micrometers, for example.

  As shown in FIGS. 4 and 5, low melting point metal parts 41 and 42 are provided on the fuse electrode parts 13 a and 13 b of the wiring 13. The low melting point metal parts 41 and 42 are made of a low melting point metal that has a melting point lower than that of the wiring 13 and that melts the wiring 13 when it becomes a melt. The low melting point metal may be composed mainly of Sn, for example. Specific examples of such low melting point metals include Sn alloys such as SnSb, SnCu, SnAg, SnAgCu, SnCuNi. The thickness of the low melting point metal parts 41 and 42 can be set to, for example, about 0.1 mm to 0.5 mm.

  Note that a protective film such as a flux layer or an antioxidant film may be provided on the low melting point metal parts 41 and 42 so as to cover at least a part of the low melting point metal parts 41 and 42.

  As shown in FIGS. 4 and 5, in the fuse 1, insulating layers 51 and 52 are arranged between the wiring 13 and the low melting point metal parts 41 and 42. The melting points of the insulating layers 51 and 52 are higher than the melting points of the low melting point metal parts 41 and 42. The melting points of the insulating layers 51 and 52 are preferably 180 ° C. to 350 ° C., and more preferably 220 ° C. to 320 ° C. The insulating layers 51 and 52 can be made of an appropriate insulating material, but are preferably made of, for example, a thermoplastic resin. Examples of the thermoplastic resin preferably used for forming the insulating layers 51 and 52 include polyester resins such as polyethylene terephthalate (PET, melting point 264 ° C.), polybutylene terephthalate (PBT, melting point 232 ° C.), and polyvinyl chloride. (Melting point 180 ° C.) vinyl resin, polystyrene (melting point 230 ° C.) polystyrene resin, nylon 6 (registered trademark, melting point 225 ° C.) and nylon 66 (registered trademark, melting point 267 ° C.) polyamide resin, Examples thereof include polycarbonate resins such as polycarbonate (melting point 250 ° C.), and fluorine resins such as polyvinylidene fluoride (melting point 210 ° C.) and ethylene trifluoride chloride (melting point 220 ° C.). The thickness of the insulating layers 51 and 52 can be, for example, about 10 μm to 200 μm, preferably about 20 to 150 μm.

  As shown in FIGS. 8 to 10, metal films 61 to 64 are disposed on the insulating substrate 20 outside the insulating layers 51 and 52. The metal films 61 to 64 are preferably made of a metal or alloy having high wettability with respect to the melt of the low melting point metal parts 41 and 42 such as Ag, AgPt, AgPd, and Cu. Furthermore, the metal films 61 to 64 are preferably not easily dissolved in the melt of the low melting point metal parts 41 and 42, and are preferably composed of AgPt, AgPd, or the like.

  The metal films 61 to 64 are provided on both sides of the insulating layers 51 and 52 in the width direction of the wiring 13. In the present embodiment, specifically, the metal films 61 and 62 are provided on both sides of the insulating layer 51 in the width direction of the wiring 13. In the width direction of the wiring 13, the metal films 61 and 62 are provided so as to sandwich the fuse electrode portion 13a. The low melting point metal part 41 is provided in contact with the metal films 61 and 62. Specifically, the low melting point metal portion 41 is provided so as to straddle the insulating layer 51 and the metal film 62 from the top of the metal film 61.

  Metal films 63 and 64 are provided on both sides of the insulating layer 52 in the width direction of the wiring 13. In the width direction of the wiring 13, the metal films 63 and 64 are provided so as to sandwich the fuse electrode portion 13b. The low melting point metal part 42 is provided in contact with the metal films 63 and 64. Specifically, the low melting point metal part 42 is provided so as to straddle the insulating layer 52 and the metal film 64 from the metal film 63.

  In addition, the metal films 61 to 64 may be configured by a stacked body of a plurality of metal films. The plurality of metal films constituting the metal films 61 to 64 may include a plurality of types of metal films having different melting points. The metal films 61 to 64 are provided on the first metal film and the first metal film, and may include a second metal film having a melting point lower than that of the first metal film. In that case, the second metal film may reach the insulating layers 51 and 52.

  The thickness of the metal films 61 to 64 can be set to, for example, about 20 μm to 40 μm.

  As shown in FIG. 1, a protective layer 70 surrounding each of the region where the low melting point metal part 41 is provided and the region where the low melting point metal part 42 is provided is provided. By providing this protective layer 70, it is possible to effectively suppress the low melting point metal melt from spreading in an unintended direction. The thickness of the protective layer 70 can be about 10 μm to 20 μm, for example.

  Next, the activation of the fuse function in the fuse 1 will be described.

  For example, when an overcurrent flows between the first terminal 11 and the second terminal 12, the narrowly provided fuse electrode portions 13a and 13b generate heat. Due to this heat generation, the low melting point metal parts 41 and 42 are heated and melted. Further, the insulating layers 51 and 52 are also melted, and the low melting point metal melt comes into contact with the fuse electrode portions 13a and 13b. As a result, the fuse electrode portions 13a and 13b are dissolved in the melt of the low melting point metal, and the wiring 13 is melted. As a result, a fuse function appears.

  In the fuse 1, insulating layers 51 and 52 are provided between the wiring 13 and the low melting point metal parts 41 and 42. The insulating layer 51, 52 electrically insulates the wiring 13 from the low melting point metal parts 41, 42. For this reason, unlike the case where the low melting point metal portion and the wiring are electrically connected, the specific resistance of the wiring 13 is large. Therefore, the wiring 13 tends to generate heat when an overcurrent flows between the first terminal 11 and the second terminal 12. Therefore, in the fuse 1, when an overcurrent flows between the first terminal 11 and the second terminal 12, the fuse function appears with high certainty.

  In the fuse 1, the melting points of the insulating layers 51 and 52 are higher than the melting points of the low melting point metal parts 41 and 42. For this reason, it is suppressed effectively that the specific resistance of the wiring 13 falls because the low melting-point metal parts 41 and 42 and the wiring 13 contact until the insulating layers 51 and 52 melt | dissolve. Therefore, the fuse function is expressed with higher certainty.

  From the viewpoint of expressing the fuse function with higher certainty, the melting points of the insulating layers 51 and 52 are preferably higher by 10 ° C. than the melting points of the low melting point metal parts 41 and, and more preferably higher by 20 ° C. However, if the melting points of the insulating layers 51 and 52 are too high relative to the melting points of the low melting point metal parts 41 and 42, the insulating layers 51 and 52 are difficult to melt, and the low melting point metal melt and the wiring 13 are difficult to contact. On the contrary, the fuse function may be difficult to develop. Therefore, the melting points of the insulating layers 51 and 52 are preferably not higher than the melting point of the low melting point metal portions 41 and 42 + 50 ° C., more preferably not higher than the melting point of the low melting point metal portions 41 and 42 + 30 ° C. Specifically, the melting points of the insulating layers 51 and 52 are preferably in the range of 180 ° C. to 350 ° C., more preferably in the range of 220 ° C. to 320 ° C., and in the range of 260 ° C. to 280 ° C. More preferably, it is within.

  By the way, in order to surely melt the wiring 13 with the melt of the low melting point metal, it is important to keep the melt of the low melting point metal in a region where the melt can be in contact with the wiring 13. Here, in this embodiment, the surface on which the low melting point metal parts 41 and 42 are provided is located outside the part on which the low melting point metal parts 41 and 42 are provided, and the low melting point metal parts 41 and 42 are provided. It has the bank part 90 which protruded upwards rather than the lowest part among the formed parts. The bank 90 suppresses the low-melting-point metal melt from spreading toward the bank 90, and the low-melting-point metal melt tends to stay on the 13a and 13b. Therefore, in the fuse 1, the fuse function can be expressed with high certainty.

  From the viewpoint of more effectively suppressing wetting and spreading of the low melting point metal melt in an unintended direction, the bank portion 90 straddles the wiring 13 outside the portion where the low melting point metal portions 41 and 42 are provided. It is preferable to be provided. It is preferable that the entire low melting point metal parts 41 and 42 are provided inside the bank part 90. But in this invention, a part of low melting metal part may be distribute | arranged on the bank part or the outer side of a bank part.

  In the present embodiment, as shown in FIG. 5, the bank portion 90 is configured by an insulating layer 91 provided between the insulating substrate 20 and the wiring 13. For this reason, the surface of the part located under the low melting-point metal parts 41 and 42 of the wiring 13 is located in the position lower than the surface of the part in which the bank part 90 of the wiring 13 was provided. Therefore, the low melting point metal melt is more effectively suppressed from spreading in an unintended direction, so that the fuse function can be expressed with higher certainty.

  A portion of the insulating layer 91 located in the region where the wiring 13 is provided is covered with the wiring 13 and further covered with the insulating layers 51 and 52. Therefore, at least a portion of the insulating layer 91 located in the region where the wiring 13 is provided is provided so as not to come into contact with the melt of the low melting point metal. Therefore, at least a portion of the insulating layer 91 located in the region where the wiring 13 is provided does not disappear when the low melting point metal melt is melted or melted in the low melting point metal melt. Therefore, the low melting point metal melt is further effectively prevented from spreading in an unintended direction, so that the fuse function can be expressed with higher reliability.

  In the present embodiment, insulating layers 51 and 52 having low wettability of the low melting point metal melt are provided below the low melting point metal parts 41 and 42. For this reason, the melt of a low melting metal tends to be displaced. Therefore, in the fuse 1, metal films 61 to 64 are arranged on the insulating substrate 20 outside the insulating layers 51 and 52. When the melt of the low melting point metal contacts the metal films 61 to 64, the melt of the low melting point metal is captured by the metal films 61 to 64. Therefore, in the fuse 1, it is possible to reliably keep the melt of the low melting point metal in a region where it can come into contact with the wiring 13. Therefore, in the fuse 1, the fuse function can be expressed with higher certainty.

  From the viewpoint of ensuring that the low-melting-point metal melt is captured by the metal films 61 to 64, the low-melting-point metal portions 41 and 42 are preferably provided so as to be in contact with the metal films 61 to 64. . In the width direction of the wiring 13, the metal films 61 to 64 are preferably provided on both sides of the insulating layers 51 and 52. In the width direction of the wiring 13, the metal films 61 to 64 are preferably provided on both sides of the fuse electrode portions 13 a and 13 b. The low melting point metal parts 41 and 42 are preferably provided across the metal film 61 and the metal film 62, and the metal film 63 and the metal film 64 provided on both sides of the wiring 13.

  In the fuse 1, even when no overcurrent flows through the first terminal 11 and the second terminal 12, the fuse function can be exhibited by causing the heating element 15 to generate heat. Specifically, the heating element 15 is caused to generate heat by applying electric power between the third terminal 14 and the terminals 11, 12 or 16. Due to the heat from the heating element 15, the low melting point metal parts 41 and 42 are melted and the fuse electrode parts 13 a and 13 b of the wiring 13 are melted.

  In the fuse 1, the heating element 15 and the wiring 13 are connected by a high thermal conductor 38 that is provided in the through hole 36 a and has a higher thermal conductivity than the insulating layer 36. For this reason, the heat of the heating element 15 is easily transmitted to the low melting point metal parts 41 and 42 via the wiring 13. Therefore, in the fuse 1, the fuse function is expressed with high certainty even when the heating element 15 is heated to actively develop the fuse function.

  From the viewpoint of expressing the fuse function with higher certainty, it is preferable that the through hole 36a is provided so as not to overlap the low melting point metal parts 41 and 42 in a plan view. When the low melting point metal parts 41 and 42 are located on the through hole 36a, the high thermal conductor 38 is conductive in order to melt the wiring 13 and insulate the first terminal 11 and the second terminal 12 from each other. In the case where it has the property, it is necessary to blow up to the high thermal conductor 38 together with the wiring 13. On the other hand, in the plan view, when the through hole 36a is provided so as not to overlap the low melting point metal parts 41 and 42, the first terminal 11 and the second terminal 12 are insulated if only the wiring 13 is melted. Is done. Accordingly, the fuse function is more easily exhibited.

DESCRIPTION OF SYMBOLS 1,1a, 1b ... fuse 11 ... 1st terminal 12 ... 2nd terminal 13 ... wiring 13a, 13b ... fuse electrode part 13c ... connection point 14 ... 3rd terminal 15 ... heating element 16 ... 4th terminal 20 ... Insulating substrate 20a ... first main surface 20b ... second main surfaces 21-24 ... electrodes 25, 27, 29, 30 ... side electrodes 26, 28 ... via hole electrodes 31, 32 ... wiring 35 ... electrode layer 36 ... Insulating layer 36a ... through hole 37 ... electrode 38 ... high thermal conductor 41, 42 ... low melting point metal part 43 ... high melting point metal part 51, 52 ... insulating layers 61-64 ... metal film 70 ... protective layer 90 ... bank part 91 ... Insulation layer

Claims (7)

An insulating substrate;
Wiring disposed on one main surface of the insulating substrate;
A low melting point metal part which is provided on the wiring and has a melting point lower than that of the wiring and which dissolves the wiring when it becomes a melt;
With
The surface on which the low melting point metal part is provided is located outside the part on which the low melting point metal part is provided, and the bank part protruding from the lowest part among the parts on which the low melting point metal part is provided have a, the bank portion is that provided straddling the wiring outside than the low melting point metal portion is provided partially fuse. The fuse according to claim 1, wherein the entire low melting point metal part is provided inside the bank part. Provided between the insulating substrate and the wiring, further comprising an insulating layer for constituting the bank portion;
The fuse according to claim 1 or 2 , wherein a surface of a portion of the wiring located under the low melting point metal portion is located at a position lower than a surface of a portion of the wiring where the bank portion is provided. . At least a portion of the insulating layer located in the region where the wiring is provided is not lost by the low melting point metal melt when the low melting point metal portion melts and a low melting point metal melt is generated. The fuse according to claim 3 , wherein the fuse is provided. 5. The fuse according to claim 4 , wherein at least a portion of the insulating layer located in a region where the wiring is provided is provided so as not to contact the melt of the low melting point metal. Wherein comprising further a heating element for heating the low melting point metal portion, the fuse according to any one of claims 1-5. The fuse according to any one of claims 1 to 6 , wherein the low-melting-point metal part contains Sn as a main component.

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