WO2012144432A1 - Anti-fuse circuit and light emitting circuit - Google Patents

Anti-fuse circuit and light emitting circuit Download PDF

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Publication number
WO2012144432A1
WO2012144432A1 PCT/JP2012/060108 JP2012060108W WO2012144432A1 WO 2012144432 A1 WO2012144432 A1 WO 2012144432A1 JP 2012060108 W JP2012060108 W JP 2012060108W WO 2012144432 A1 WO2012144432 A1 WO 2012144432A1
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Prior art keywords
circuit
antifuse
light emitting
electrode layer
layer
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PCT/JP2012/060108
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French (fr)
Japanese (ja)
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晋輔 谷
竹島　裕
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株式会社村田製作所
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Priority to JP2013510973A priority Critical patent/JP5435174B2/en
Publication of WO2012144432A1 publication Critical patent/WO2012144432A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/52—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames
    • H01L23/522—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body
    • H01L23/525—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body with adaptable interconnections
    • H01L23/5252—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body with adaptable interconnections comprising anti-fuses, i.e. connections having their state changed from non-conductive to conductive
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
    • H01L25/16—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof the devices being of types provided for in two or more different main groups of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. forming hybrid circuits
    • H01L25/167—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof the devices being of types provided for in two or more different main groups of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. forming hybrid circuits comprising optoelectronic devices, e.g. LED, photodiodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/62—Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Definitions

  • the present invention relates to an antifuse circuit, and more particularly, to an antifuse circuit with a small calorific value, a small size, and a low cost.
  • the present invention also relates to a light emitting circuit using the antifuse circuit.
  • a method of connecting an antifuse circuit that functions when an LED element has an open failure in parallel with each of a plurality of LED elements connected in series can be considered. That is, when an LED element has an open failure, the current is diverted to an antifuse circuit connected in parallel with the LED element, and the light emission of other LED elements connected in series is maintained.
  • the antifuse circuit includes, for example, an anti-semiconductor device (FPGA: FieldFProgrammable Gate Array) as disclosed in Patent Document 1 (Patent No. 3895099) and Patent Document 2 (Patent No. 3256603). It is conceivable to use a fuse element. This anti-fuse element irreversibly decreases its resistance when an overvoltage is applied, and functions as a bypass circuit.
  • FPGA FieldFProgrammable Gate Array
  • this antifuse element cannot stably supply a current of several tens of mA or more, and cannot be used in an antifuse circuit for an LED element having a current amount of several tens to several hundred mA. .
  • Patent Document 3 Japanese Patent Application Laid-Open No. 2008-131007
  • a detection circuit that detects an open failure of the LED element and a bypass circuit that bypasses the current in the case of an open failure of the LED element.
  • An antifuse circuit is configured, and the antifuse circuit is connected in parallel with each LED element.
  • FIG. 4 shows a light emitting circuit 300 disclosed in Patent Document 3.
  • a plurality of LED elements 101 are connected in series, and an antifuse circuit 102 is connected in parallel with each LED element 101.
  • the antifuse circuit 102 includes a detection circuit 103 and a bypass circuit 104 connected in parallel to each other.
  • the detection circuit 103 includes a series circuit of a resistor 103R 1 and the resistor 103R 2, one end to the connection point of the resistors 103R 1 and the resistor 103R 2 is constituted by a resistor 103R 3 connected.
  • the bypass circuit 104 includes a thyristor 104T as a control rectifier. The other end of the resistor 103R 3 of the detection circuit 103 is connected to the gate of the thyristor 104T of the bypass circuit 104.
  • Zener diode may be used instead of the resistor 103R 1 .
  • a PNP transistor and an NPN transistor can be combined to have the same function as the thyristor.
  • a bidirectional thyristor may be used instead of the thyristor 104T.
  • the resistor 103R 3 is for preventing the thyristor 104T from being destroyed.
  • the thyristor 104T is turned on to energize between the anode and the cathode.
  • the thyristor 104T maintains an on state even when the gate current becomes zero, and can continue to supply a large current until the voltage between the anode and the cathode becomes zero voltage or reverse voltage. Therefore, after the thyristor 104T is turned on, a large current can continue to flow at a voltage lower than the forward voltage of the LED element 101.
  • the conventional light emitting circuit 300 described above has the following problems.
  • the thyristor 104T used in the bypass circuit 104 of the antifuse circuit 102 has a large shape and a high cost
  • the light emitting circuit 300 is large in the bypass circuit 104, the antifuse circuit 102, and eventually the light emitting circuit 300.
  • the cost becomes high.
  • the thyristor 104T is equivalent to a composite circuit in which a PNP transistor and an NPN transistor are combined, and is generally larger in shape and more expensive than a transistor. Since the same number of thyristors 104T as the LED elements 101 are used in the light emitting circuit 300, the entire light emitting circuit 300 is increased in size and cost.
  • the detection circuit 103 detects it as an overvoltage, and the thyristor 104T is turned on, causing a malfunction. There was a problem of doing.
  • the thyristor 104T maintains the ON state even when the gate current becomes zero, and energizes between the anode and the cathode.
  • the LED element 101 connected in parallel with the thyristor 104T cannot obtain a rated voltage, and there is a serious problem that the LED element 101 is turned off despite no open failure.
  • the transistor As described above, the transistor is small in shape and inexpensive compared to the thyristor 104T.
  • a transistor is an element in which the resistance value between the collector and the emitter is freely changed when the base current is changed. When a minute current is supplied from the base, the transistor is several hundred times larger between the collector and the emitter. Current is generated. Therefore, when static electricity or the like is applied, even if it is turned on at that moment, it is immediately turned off, so that the LED element 101 that does not have an open failure cannot obtain the rated voltage and is not turned off. .
  • the transistor is an element in which the resistance between the collector and the emitter changes according to the base current. Therefore, in order to keep the current flowing between the collector and the emitter, the transistor is always turned on. It is necessary to continue to maintain (a state where a voltage higher than the rated voltage of the LED element 101 is applied to the detection circuit 103). In this case, since it becomes an antifuse circuit which maintains an energized state by continuing to apply a voltage higher than the forward voltage of the LED element 101, the amount of heat generated is larger than the amount of heat generated by one LED element. A new problem arises.
  • the antifuse circuit of the present invention includes a detection circuit and a bypass circuit connected in parallel to each other, and the detection circuit includes an antifuse element and a resistance element connected in series to the antifuse element.
  • the bypass circuit includes a transistor having a base connected to a connection point between the antifuse element and the resistance element.
  • the antifuse element includes an insulator thin film layer, and a lower electrode layer and an upper electrode layer respectively formed on both surfaces of the insulator thin film layer, and the insulator thin film is generated by heat generated when an overvoltage is applied.
  • the insulation of the layers is broken, the lower electrode layer and the upper electrode layer are melted, and the molten lower electrode layer and the upper electrode layer are fused and electrically connected. In this case, malfunction due to static electricity or the like can be avoided.
  • a light-emitting circuit can be configured using the antifuse circuit of the present invention.
  • the light emitting circuit has the advantages of the antifuse circuit of the present invention.
  • the antifuse circuit of the present invention having the above-described configuration uses a transistor instead of a thyristor in the bypass circuit, so that the shape is small and the cost is low.
  • the anti-fuse element used in the detection circuit is irreversible once the resistance is lowered. After detecting an open failure of a light-emitting element (such as an LED) and operating it, it remains constant even below the rated voltage of the light-emitting element.
  • the base current can be supplied to the transistor to keep the current between the collector and the emitter. That is, the antifuse circuit of the present invention can be designed to keep the transistor on at a voltage lower than the rated voltage of the light emitting element, and the amount of heat generated during operation is kept smaller than the amount of heat generated by the light emitting element. be able to.
  • FIG. 1 is a circuit diagram showing a light emitting circuit 100 according to a first embodiment of the present invention. 1 shows an example of an antifuse element used in the light emitting circuit according to the first embodiment of the present invention shown in FIG. 1, FIG. 2A is a plan view, and FIG. 2B is an arrow X in FIG. It is sectional drawing of -X part. It is a circuit diagram which shows the light emitting circuit 200 concerning 2nd Embodiment of this invention.
  • FIG. 6 is a circuit diagram showing a conventional light emitting circuit 300.
  • FIG. 1 shows a circuit diagram of a light emitting circuit 100 according to the first embodiment of the present invention.
  • a plurality of LED elements 1 are connected in series, and an antifuse circuit 2 is connected in parallel with each LED element 1.
  • the antifuse circuit 2 includes a detection circuit 3 and a bypass circuit 4 connected in parallel to each other. Then, the detection circuit 3, and a anti-fuse element 3AF a series circuit of a resistor 3R 1, a resistor 3R 2 having one end connected to a connection point of the anti-fuse element 3AF and resistor 3R 1.
  • the bypass circuit 4 includes a transistor 4Tr as a control rectifier. The other end of the resistor 3R 2 of the detection circuit 3 is connected to the base of the transistor 4Tr of the bypass circuit 4.
  • the transistor 4Tr generates a current several hundred times as large as the current input from the base through the antifuse element 3AF between the collector and the emitter.
  • the resistor 3R 1 divides the voltage applied to both ends of the LED element 1 with the antifuse element 3AF, thereby stably operating the antifuse element 3AF. After the antifuse element 3AF is activated, the antifuse element 3AF is energized. It has a function of suppressing current.
  • the resistor 3R 2 has a function of preventing the transistor 4Tr from being destroyed.
  • a 1 A constant current power source (the upper limit of the voltage is 20 V or more) is used as a power source (not shown).
  • a resistance element of 330 ⁇ was used for the resistor 3R 1, and a resistance element of 10 ⁇ was used for the resistor 3R 2 .
  • a transistor 4Tr having a base-emitter voltage of 0.6 V and a current of 1 mA flowing between the base and emitter was used.
  • the antifuse circuit 2 of the light emitting circuit 100 of the present embodiment operates as follows.
  • the LED element 1 when the LED element 1 is operating normally, for example, if the VF value of the LED element 1 is 3V, a voltage of 3V is divided by the antifuse element 3AF (several M ⁇ ) and the resistor 3R 1 (330 ⁇ ). Almost all voltages are applied to the antifuse element 3AF side. At this time, although a slight leak current is generated in the anti-fuse element 3AF, the base of the transistor 4Tr - because people as compared with the resistance between the emitter of the resistor resistance 3R 1 is low, the leakage current through the resistor 3R 1 side Flowing. Therefore, the transistor 4Tr is not turned on and almost no current flows between the collector and the emitter.
  • the antifuse element 3AF operates when a voltage of 20 V or more is applied, and irreversibly lowers the resistance (several ⁇ ).
  • the voltage applied between the base and the emitter of the transistor 4Tr increases and the transistor 4Tr is turned on, so that a collector-emitter current is generated according to the amount of current supplied to the base, and the base current And the collector-emitter current are adjusted so that the sum of the current between the collector and the emitter becomes 1 A (maximum current amount of the power supply).
  • the amount of current flowing through the antifuse element 3AF is about 8.6 mA
  • the collector-emitter current is about 990 mA
  • the voltage across the LED element 1 is 1.18V.
  • an antifuse element 13AF having a structure shown in FIGS. 2A and 2B can be used.
  • FIG. 2A is a plan view showing the antifuse element 13AF
  • FIG. 2B is a cross-sectional view taken along the line XX in FIG. (In FIGS. 2A and 2B, for the sake of convenience, the reference numeral indicating the antifuse element is “13AF”.)
  • the antifuse element 13AF has an insulating thin film layer 21, and a lower electrode layer 22 and an upper electrode layer 23 formed on both surfaces thereof as basic elements.
  • the insulation of the insulator thin film layer 21 is broken due to heat generation, the lower electrode layer 22 and the upper electrode layer 23 are melted, and the lower electrode layer 22 and the upper electrode layer 23 are It is fused and electrically connected to irreversibly reduce the resistance.
  • the antifuse element 13AF will be described.
  • the antifuse element 13AF includes a substrate 24.
  • a substrate 24 for example, a Si single crystal substrate is used.
  • An oxide layer 25 is formed on the surface of the substrate 24 to ensure insulation.
  • SiO 2 is used for the oxide layer 25.
  • an adhesion layer 26 is formed on the oxide layer 25.
  • the adhesion layer 26 is for ensuring adhesion between the oxide layer 25 and the lower electrode layer 22 to be described next.
  • the same material as the insulator thin film layer 21 to be described next is used.
  • a lower electrode layer 22, an insulator thin film layer 21, and an upper electrode layer 23 are formed in this order on the adhesion layer 26.
  • PtAu is used for the lower electrode layer 22 and the upper electrode layer 23.
  • the thicknesses of the lower electrode layer 22 and the upper electrode layer 23 are, for example, about 100 to 500 nm.
  • the insulator thin film layer 21 for example, (Ba, Sr) TiO 3 (hereinafter referred to as “BST”), SrTiO 3 , BaTiO 3 , Pb (Zr, Ti) O 3 , SrBi 4 Ti 4 O 15 or the like is used. It is done.
  • the thickness of the insulating thin film layer 21 is, for example, about 50 to 200 nm.
  • An upper insulating layer 27 is formed on the upper electrode layer 23 as necessary.
  • the upper insulating layer 27 is for reducing leakage current from the upper electrode layer 23 and the like, and the same material as that of the insulating thin film layer 21 is used here, for example.
  • the inorganic protective layer 28 and the organic protective layer 29 are further formed on these.
  • the inorganic protective layer 28 and the organic protective layer 29 are both formed to prevent moisture from entering the inside, and the inorganic protective layer 28 includes, for example, SiN x , SiO 2 , Al 2.
  • polyimide resin or epoxy resin is used for the organic protective layer 29, such as O 3 and TiO 2 .
  • the lower electrode layer 22 is extracted to the external electrode 33a via the via hole 31a and the extraction electrode 32a, and the upper electrode layer 23 is extracted to the external electrode 33b via the via hole 31b and the extraction electrode 32b.
  • the extraction electrodes 32a and 32b are formed on the organic protective layer 29, and the external electrodes 33a and 33b are formed on the extraction electrodes 32a and 32b.
  • the second organic protective layer 30 is also made of, for example, polyimide resin or epoxy resin.
  • the antifuse element 13AF having such a structure is manufactured, for example, by the following method.
  • the materials and materials used for each element are examples.
  • an adhesion layer 26 made of BST is formed on the oxide layer 25 by chemical solution deposition (CSD). Specifically, a dielectric material solution containing BST is applied by spin coating, dried, and heat-treated.
  • the lower electrode layer 22 made of Pt is formed on the adhesion layer 26 by sputtering.
  • the insulator thin film layer 21 made of BST is formed on the lower electrode layer 22 by the same method as the adhesion layer 26.
  • the upper electrode layer 23 made of Pt is formed on the insulator thin film layer 21 in the same manner as the lower electrode layer 22.
  • the upper insulating layer 27 made of BST is formed on the upper electrode layer 23 by the same method as the adhesion layer 26 and the insulating thin film layer 21.
  • the upper insulating layer 27 and the upper electrode layer 23 are etched to have a predetermined shape, and then the insulating thin film layer 21, the lower electrode layer 22, and the adhesion layer 26 are etched to have a predetermined shape. At this time, the upper insulating layer 27 and the upper electrode layer 23 are provided with openings for passing the via holes 31a.
  • an inorganic protective layer 28 made of SiO x is formed on these laminated structures by plasma enhanced chemical vapor deposition (PECVD).
  • PECVD plasma enhanced chemical vapor deposition
  • an organic protective layer 29 made of polyimide resin is formed on the inorganic protective layer 28. Specifically, it is formed by spin-coating photosensitive polyimide, exposing, developing, and curing.
  • the inorganic protective layer 28 is patterned using CHF 3 gas. At this time, an opening is formed and the lower electrode layer 22 and the upper electrode layer 23 are exposed.
  • via holes 31 a and 31 b are formed in the openings formed in the inorganic protective layer 28 and the organic protective layer 29, and extraction electrodes 32 a and 32 b are formed on the organic protective layer 29.
  • a Ti layer and a Cu layer are continuously formed by using magnetron sputtering, the via holes 31a and 31b are formed by filling the openings, and a metal film is formed on the entire surface of the organic protective layer 29.
  • extraction electrodes 32a and 32b are formed in a predetermined pattern using ion milling with the resist pattern formed by resist application, exposure and development as a mask.
  • the second organic protective layer 30 is formed by partially exposing the extraction electrodes 32a and 32b through the openings. Specifically, a photosensitive resin material is applied by spin coating, exposed, developed, and cured to obtain an epoxy resin layer.
  • an Ni layer and an Au layer are sequentially formed on the extraction electrodes 32a and 32b exposed from the opening of the second organic protective layer 30 by, for example, electroplating, and external electrodes 33a and 33b are formed. Element 13AF is completed.
  • the antifuse element 13AF having the above-described structure and capable of being manufactured by the above-described method has a large capacitance of about 1 to 100 nF, and does not operate because it can temporarily store charges even when static electricity is applied. . Therefore, if this antifuse element 13AF is used as the antifuse element 3AF of the light emitting circuit 100 according to the present embodiment, it operates even when static electricity is applied while the LED element 1 is energized (in a state where no open failure occurs). There is nothing. That is, it does not malfunction due to static electricity.
  • the light emitting circuit 100 has been described above.
  • the present invention is not limited to the above contents, and design changes can be made in accordance with the gist of the invention.
  • the resistance 3R 1 , the resistance value of the resistance 3R 1 , the characteristics of the transistor 4Tr, and the like are not limited to the above, and can be changed.
  • the antifuse element to be used is not limited to the structure shown by reference numeral 13AF, and other structures can be used as long as the resistance is irreversibly lowered by overvoltage.
  • FIG. 3 shows a circuit diagram of a light emitting circuit 200 according to the second embodiment of the present invention.
  • two LED elements 1A and 1B constitute one LED element group, and an antifuse circuit 2 is connected in parallel with each of the LED element groups.
  • the antifuse circuit 2 is the same as that used in the light emitting circuit 100 according to the first embodiment described above.
  • the number of antifuse circuits 2 to be used can be halved with respect to the total number of LED elements. However, even if any one of the LED elements 1A and 1B has an open failure, both the LED elements 1A and 1B are turned off as the LED element group. Of course, even in this case, the lighting of the other LED element groups can be maintained.
  • LED element 2 Antifuse circuit 3: Detection circuit (part of the antifuse circuit) 3AF, 13AF: anti-fuse element 3R 1, 3R 2: resistors 4: bypass circuit (part of the anti-fuse circuit) 4Tr: transistor 21: insulator thin film layer 22: lower electrode layer 23: upper electrode layer 24: substrate 25: oxide layer 26: adhesion layer 27: upper insulating layer 28: inorganic protective layer 29: organic protective layer 30: second Organic protective layers 31a, 31b: via holes 32a, 32b: extraction electrodes 33a, 33b: external electrodes

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Abstract

Provided is an anti-fuse circuit that is small and low cost and generates a small amount of heat. This anti-fuse circuit is provided with a detection circuit and a bypass circuit connected to each other in parallel. The detection circuit comprises an anti-fuse element that becomes irreversibly low resistance because of excessive voltage and a circuit with a resistor element in series. The bypass circuit is constituted by including a transistor that conducts electricity according to the voltage at the contact point of the anti-fuse element and the resistor element.

Description

アンチヒューズ回路および発光回路Antifuse circuit and light emitting circuit
　本発明は、アンチヒューズ回路に関し、さらに詳しくは、発熱量が小さく、小型で、低コストのアンチヒューズ回路に関する。 The present invention relates to an antifuse circuit, and more particularly, to an antifuse circuit with a small calorific value, a small size, and a low cost.
　また本発明は、上記アンチヒューズ回路を用いた発光回路に関する。 The present invention also relates to a light emitting circuit using the antifuse circuit.
　近時、大電流（数百ｍＡ以上）を流せるＬＥＤ素子が開発され、これを用いた非常に明るい発光回路が実用化されている。そして、この発光回路において、電力を効率的に利用するためには、複数のＬＥＤ素子を直列に接続することが有効である。 Recently, an LED element capable of flowing a large current (several hundred mA or more) has been developed, and a very bright light emitting circuit using the LED element has been put into practical use. And in this light emitting circuit, in order to utilize electric power efficiently, it is effective to connect a some LED element in series.
　しかしながら、複数のＬＥＤ素子を直列に接続した発光回路においては、複数のＬＥＤ素子のうちの１つのＬＥＤ素子がオープン故障となった場合においても、全てのＬＥＤ素子が消灯してしまうという問題があった。 However, in a light emitting circuit in which a plurality of LED elements are connected in series, even when one of the plurality of LED elements has an open failure, all the LED elements are turned off. It was.
　この問題を解決する方法として、直列に接続された複数のＬＥＤ素子のそれぞれと並列に、ＬＥＤ素子がオープン故障となった場合に機能するアンチヒューズ回路を接続する方法が考えられる。すなわち、ＬＥＤ素子がオープン故障となった場合、そのＬＥＤ素子と並列に接続されたアンチヒューズ回路に電流を迂回させ、直列に接続された他のＬＥＤ素子の発光を維持するものである。 As a method of solving this problem, a method of connecting an antifuse circuit that functions when an LED element has an open failure in parallel with each of a plurality of LED elements connected in series can be considered. That is, when an LED element has an open failure, the current is diverted to an antifuse circuit connected in parallel with the LED element, and the light emission of other LED elements connected in series is maintained.
　そして、そのアンチヒューズ回路に、たとえば、特許文献１（特許第３８９５０９９号公報）や特許文献２（特許第３２５６６０３号公報）に開示されるような、半導体デバイス（ＦＰＧＡ；Field Programmable Gate Array）用アンチヒューズ素子を用いることが考えられる。このアンチヒューズ素子は、過電圧が印加されると不可逆に低抵抗化し、バイパス回路として機能する。 The antifuse circuit includes, for example, an anti-semiconductor device (FPGA: FieldＦProgrammable Gate Array) as disclosed in Patent Document 1 (Patent No. 3895099) and Patent Document 2 (Patent No. 3256603). It is conceivable to use a fuse element. This anti-fuse element irreversibly decreases its resistance when an overvoltage is applied, and functions as a bypass circuit.
　しかしながら、このアンチヒューズ素子は、数十ｍＡ以上の電流を安定的に通電することができず、数十～数百ｍＡ以上の電流量のＬＥＤ素子に対するアンチヒューズ回路には用いることができなかった。 However, this antifuse element cannot stably supply a current of several tens of mA or more, and cannot be used in an antifuse circuit for an LED element having a current amount of several tens to several hundred mA. .
　そこで、特許文献３（特開２００８－１３１００７号公報）に開示された発光回路では、ＬＥＤ素子のオープン故障を検出する検出回路と、ＬＥＤ素子のオープン故障の場合に電流を迂回させるバイパス回路とでアンチヒューズ回路を構成し、そのアンチヒューズ回路を各ＬＥＤ素子と並列に接続するようにしている。 Therefore, in the light emitting circuit disclosed in Patent Document 3 (Japanese Patent Application Laid-Open No. 2008-131007), a detection circuit that detects an open failure of the LED element and a bypass circuit that bypasses the current in the case of an open failure of the LED element. An antifuse circuit is configured, and the antifuse circuit is connected in parallel with each LED element.
　図４に、特許文献３に開示された発光回路３００を示す。 FIG. 4 shows a light emitting circuit 300 disclosed in Patent Document 3.
　発光回路３００は、複数のＬＥＤ素子１０１が直列に接続され、各ＬＥＤ素子１０１それぞれと並列に、アンチヒューズ回路１０２が接続されている。 In the light emitting circuit 300, a plurality of LED elements 101 are connected in series, and an antifuse circuit 102 is connected in parallel with each LED element 101.
　アンチヒューズ回路１０２は、相互に並列に接続された、検出回路１０３とバイパス回路１０４とで構成されている。そして、検出回路１０３は、抵抗１０３Ｒ1と抵抗１０３Ｒ2との直列回路と、抵抗１０３Ｒ1と抵抗１０３Ｒ2との接続点に一端が接続された抵抗１０３Ｒ3とで構成されている。また、バイパス回路１０４は、制御整流素子としてのサイリスタ１０４Ｔで構成されている。そして、検出回路１０３の抵抗１０３Ｒ3の他端が、バイパス回路１０４のサイリスタ１０４Ｔのゲートに接続されている。 The antifuse circuit 102 includes a detection circuit 103 and a bypass circuit 104 connected in parallel to each other. The detection circuit 103 includes a series circuit of a resistor 103R 1 and the resistor 103R 2, one end to the connection point of the resistors 103R 1 and the resistor 103R 2 is constituted by a resistor 103R 3 connected. The bypass circuit 104 includes a thyristor 104T as a control rectifier. The other end of the resistor 103R 3 of the detection circuit 103 is connected to the gate of the thyristor 104T of the bypass circuit 104.
　なお、抵抗１０３Ｒ1に代えて、ツェナダイオードを用いることもできる。また、サイリスタ１０４Ｔに代えて、ＰＮＰトランジスタとＮＰＮトランジスタとを組合せて、サイリスタと同様の機能をもたせることもできる。また、サイリスタ１０４Ｔに代えて、双方向サイリスタを用いても良い。なお、抵抗１０３Ｒ3は、サイリスタ１０４Ｔの破壊を防止するためのものである。 Note that a Zener diode may be used instead of the resistor 103R 1 . Further, instead of the thyristor 104T, a PNP transistor and an NPN transistor can be combined to have the same function as the thyristor. Further, a bidirectional thyristor may be used instead of the thyristor 104T. The resistor 103R 3 is for preventing the thyristor 104T from being destroyed.
　発光回路３００において、ＬＥＤ素子１０１がオープン故障を起こすと、そのＬＥＤ素子１０１と並列に接続された検出回路１０３の抵抗１０３Ｒ1と抵抗１０３Ｒ2との接続点における電圧が上昇し、バイパス回路１０４のサイリスタ１０４Ｔのゲートに電流が流入する。この結果、サイリスタ１０４Ｔはオンし、アノードとカソードとの間を通電させる。 In the light emitting circuit 300, when the LED element 101 causes an open fault, the voltage at the connection point between the resistance 103R 1 detection circuit 103 connected in parallel with the LED element 101 and the resistor 103R 2 increases, the bypass circuit 104 A current flows into the gate of the thyristor 104T. As a result, the thyristor 104T is turned on to energize between the anode and the cathode.
　サイリスタ１０４Ｔは、ゲート電流がゼロになってもオン状態を維持し、アノードとカソードとの間がゼロ電圧または逆電圧になるまで、大電流を通電し続けることができる。したがって、サイリスタ１０４Ｔがオンした後は、ＬＥＤ素子１０１の順方向電圧よりも低い電圧で大電流を流し続けることができる。 The thyristor 104T maintains an on state even when the gate current becomes zero, and can continue to supply a large current until the voltage between the anode and the cathode becomes zero voltage or reverse voltage. Therefore, after the thyristor 104T is turned on, a large current can continue to flow at a voltage lower than the forward voltage of the LED element 101.
特許第３８９５０９９号公報Japanese Patent No. 3895099 特許第３２５６６０３号公報Japanese Patent No. 3256603 特開２００８－１３１００７号公報JP 2008-131007 A
　しかしながら、上述した従来の発光回路３００には、次のような問題があった。 However, the conventional light emitting circuit 300 described above has the following problems.
　まず、発光回路３００には、アンチヒューズ回路１０２のバイパス回路１０４に使用される、サイリスタ１０４Ｔの形状が大きく、かつ高コストであるため、バイパス回路１０４、アンチヒューズ回路１０２、ひいては発光回路３００が大きく、かつ高コストになってしまうという問題があった。 First, since the thyristor 104T used in the bypass circuit 104 of the antifuse circuit 102 has a large shape and a high cost, the light emitting circuit 300 is large in the bypass circuit 104, the antifuse circuit 102, and eventually the light emitting circuit 300. In addition, there is a problem that the cost becomes high.
　すなわち、サイリスタ１０４Ｔは、ＰＮＰトランジスタとＮＰＮトランジスタとを組合せた複合回路と等価であり、一般に、トランジスタと比較して形状が大きく高価である。発光回路３００においては、ＬＥＤ素子１０１と同数のサイリスタ１０４Ｔが使用されているため、発光回路３００全体として大型化、高コスト化をまねく原因となっていた。 That is, the thyristor 104T is equivalent to a composite circuit in which a PNP transistor and an NPN transistor are combined, and is generally larger in shape and more expensive than a transistor. Since the same number of thyristors 104T as the LED elements 101 are used in the light emitting circuit 300, the entire light emitting circuit 300 is increased in size and cost.
　また、発光回路３００には、ＬＥＤ素子１０１の通電中（オープン故障していない状態）に静電気などが印加されると、検出回路１０３が過電圧として検出してしまい、サイリスタ１０４Ｔがオンし、誤作動してしまうという問題があった。 In addition, if static electricity or the like is applied to the light emitting circuit 300 while the LED element 101 is energized (a state in which no open failure occurs), the detection circuit 103 detects it as an overvoltage, and the thyristor 104T is turned on, causing a malfunction. There was a problem of doing.
　上述のとおり、サイリスタ１０４Ｔは、ゲート電流がゼロになってもオン状態を維持し、アノードとカソードとの間を通電させる。この結果、サイリスタ１０４Ｔと並列に接続されたＬＥＤ素子１０１は、定格電圧を得ることができなくなり、オープン故障していないにもかかわらず消灯してしまうという、深刻な問題が生じていた。 As described above, the thyristor 104T maintains the ON state even when the gate current becomes zero, and energizes between the anode and the cathode. As a result, the LED element 101 connected in parallel with the thyristor 104T cannot obtain a rated voltage, and there is a serious problem that the LED element 101 is turned off despite no open failure.
　これらの問題を解決する方法として、発光回路３００のサイリスタ１０４Ｔを、トランジスタに置き換えることが考えられる。上述のとおり、トランジスタは、サイリスタ１０４Ｔに比較して、形状が小さく安価である。また、トランジスタは、ベース電流を変化させると、コレクタとエミッタとの間の抵抗値が自在に変化する素子であり、ベースから微小電流を投入すると、コレクタとエミッタとの間に、その数百倍の電流が発生するものである。したがって、静電気などが印加された場合、その瞬間にオンすることがあっても、すぐにターンオフするため、オープン故障していないＬＥＤ素子１０１が定格電圧を得られなくなり、消灯してしまうことがない。 As a method for solving these problems, it is conceivable to replace the thyristor 104T of the light emitting circuit 300 with a transistor. As described above, the transistor is small in shape and inexpensive compared to the thyristor 104T. A transistor is an element in which the resistance value between the collector and the emitter is freely changed when the base current is changed. When a minute current is supplied from the base, the transistor is several hundred times larger between the collector and the emitter. Current is generated. Therefore, when static electricity or the like is applied, even if it is turned on at that moment, it is immediately turned off, so that the LED element 101 that does not have an open failure cannot obtain the rated voltage and is not turned off. .
　しかしながら、サイリスタ１０４Ｔをトランジスタに置き換えると、発熱量が大きくなるという別の問題が発生する。上述のとおり、トランジスタは、ベース電流に応じてコレクタとエミッタとの間の抵抗が変化する素子であることから、コレクタとエミッタとの間に電流を流し続けるためには、常にトランジスタをオンした状態（検出回路１０３にＬＥＤ素子１０１の定格電圧以上の電圧がかかった状態）を維持し続ける必要がある。この場合、ＬＥＤ素子１０１の順方向電圧よりも高い電圧を印加し続けることで通電状態を維持するアンチヒューズ回路となるため、その発熱量が１個のＬＥＤ素子の発熱量よりも大きくなってしまうという、新たな問題が発生するのである。 However, when the thyristor 104T is replaced with a transistor, another problem that the amount of generated heat increases. As described above, the transistor is an element in which the resistance between the collector and the emitter changes according to the base current. Therefore, in order to keep the current flowing between the collector and the emitter, the transistor is always turned on. It is necessary to continue to maintain (a state where a voltage higher than the rated voltage of the LED element 101 is applied to the detection circuit 103). In this case, since it becomes an antifuse circuit which maintains an energized state by continuing to apply a voltage higher than the forward voltage of the LED element 101, the amount of heat generated is larger than the amount of heat generated by one LED element. A new problem arises.
　本発明は、上述した、従来技術の有する問題点を解決するためになされたものである。その手段として、本発明のアンチヒューズ回路は、相互に並列に接続された、検出回路とバイパス回路とを備え、検出回路は、アンチヒューズ素子と、そのアンチヒューズ素子に直列に接続された抵抗素子を含み、バイパス回路は、前記アンチヒューズ素子と前記抵抗素子との接続点に、ベースが接続されたトランジスタを含む構成とした。この結果、本発明のアンチヒューズ回路は、形状が小さく、低コストで、作動した場合の発熱量を小さく抑えることができる。 The present invention has been made to solve the above-described problems of the prior art. As its means, the antifuse circuit of the present invention includes a detection circuit and a bypass circuit connected in parallel to each other, and the detection circuit includes an antifuse element and a resistance element connected in series to the antifuse element. The bypass circuit includes a transistor having a base connected to a connection point between the antifuse element and the resistance element. As a result, the antifuse circuit of the present invention has a small shape and low cost, and can suppress a heat generation amount when operated.
　なお、アンチヒューズ素子は、絶縁体薄膜層と、当該絶縁体薄膜層の両面にそれぞれ形成された下部電極層および上部電極層とを備え、過電圧が印加された場合に生じる発熱により、絶縁体薄膜層の絶縁が破壊されるとともに、下部電極層と上部電極層とが溶融し、溶融した下部電極層と上部電極層とが融着して電気的に接続される構造とすることができる。この場合には、静電気などによる誤作動を回避することができる。 The antifuse element includes an insulator thin film layer, and a lower electrode layer and an upper electrode layer respectively formed on both surfaces of the insulator thin film layer, and the insulator thin film is generated by heat generated when an overvoltage is applied. The insulation of the layers is broken, the lower electrode layer and the upper electrode layer are melted, and the molten lower electrode layer and the upper electrode layer are fused and electrically connected. In this case, malfunction due to static electricity or the like can be avoided.
　また、本発明のアンチヒューズ回路を用いて、発光回路を構成することができる。この場合には、本発明のアンチヒューズ回路の利点を備えた発光回路となる。 Further, a light-emitting circuit can be configured using the antifuse circuit of the present invention. In this case, the light emitting circuit has the advantages of the antifuse circuit of the present invention.
　上記構成からなる本発明のアンチヒューズ回路は、バイパス回路に、サイリスタに替えてトランジスタを使用しているため、形状が小さく、低コストである。 The antifuse circuit of the present invention having the above-described configuration uses a transistor instead of a thyristor in the bypass circuit, so that the shape is small and the cost is low.
　また、検出回路に使用されるアンチヒューズ素子は、一度低抵抗化すると不可逆なものであり、発光素子（ＬＥＤなど）のオープン故障を検出し、作動した後は、発光素子の定格電圧以下でも一定の電流を通電し、トランジスタにコレクタ‐エミッタ間の電流を維持し続けるためのベース電流を供給することができる。すなわち、本発明のアンチヒューズ回路は、発光素子の定格電圧以下でトランジスタのオン状態を維持するように設計することが可能であり、作動時の発熱量を、発光素子の発熱量よりも小さく抑えることができる。 The anti-fuse element used in the detection circuit is irreversible once the resistance is lowered. After detecting an open failure of a light-emitting element (such as an LED) and operating it, it remains constant even below the rated voltage of the light-emitting element. The base current can be supplied to the transistor to keep the current between the collector and the emitter. That is, the antifuse circuit of the present invention can be designed to keep the transistor on at a voltage lower than the rated voltage of the light emitting element, and the amount of heat generated during operation is kept smaller than the amount of heat generated by the light emitting element. be able to.
本発明の第１実施形態にかかる発光回路１００を示す回路図である。1 is a circuit diagram showing a light emitting circuit 100 according to a first embodiment of the present invention. 図１に示す本発明の第１実施形態にかかる発光回路に使用されるアンチヒューズ素子の一例を示し、図２（Ａ）は平面図、図２（Ｂ）は図２（Ａ）の矢印Ｘ‐Ｘ部分の断面図である。1 shows an example of an antifuse element used in the light emitting circuit according to the first embodiment of the present invention shown in FIG. 1, FIG. 2A is a plan view, and FIG. 2B is an arrow X in FIG. It is sectional drawing of -X part. 本発明の第２実施形態にかかる発光回路２００を示す回路図である。It is a circuit diagram which shows the light emitting circuit 200 concerning 2nd Embodiment of this invention. 従来の発光回路３００を示す回路図である。FIG. 6 is a circuit diagram showing a conventional light emitting circuit 300.
　以下、本発明を実施するための形態について、図面を用いて説明する。 Hereinafter, modes for carrying out the present invention will be described with reference to the drawings.
　（第１実施形態）
　図１に、本発明の第１実施形態にかかる発光回路１００の回路図を示す。 (First embodiment)
FIG. 1 shows a circuit diagram of a light emitting circuit 100 according to the first embodiment of the present invention.
　発光回路１００は、複数のＬＥＤ素子１が直列に接続され、各ＬＥＤ素子１それぞれと並列に、アンチヒューズ回路２が接続されている。 In the light emitting circuit 100, a plurality of LED elements 1 are connected in series, and an antifuse circuit 2 is connected in parallel with each LED element 1.
　アンチヒューズ回路２は、相互に並列に接続された、検出回路３とバイパス回路４とで構成されている。そして、検出回路３は、アンチヒューズ素子３ＡＦと抵抗３Ｒ1との直列回路と、アンチヒューズ素子３ＡＦと抵抗３Ｒ1との接続点に一端が接続された抵抗３Ｒ2とで構成されている。また、バイパス回路４は、制御整流素子としてのトランジスタ４Ｔｒで構成されている。そして、検出回路３の抵抗３Ｒ2の他端が、バイパス回路４のトランジスタ４Ｔｒのベースに接続されている。 The antifuse circuit 2 includes a detection circuit 3 and a bypass circuit 4 connected in parallel to each other. Then, the detection circuit 3, and a anti-fuse element 3AF a series circuit of a resistor 3R 1, a resistor 3R 2 having one end connected to a connection point of the anti-fuse element 3AF and resistor 3R 1. The bypass circuit 4 includes a transistor 4Tr as a control rectifier. The other end of the resistor 3R 2 of the detection circuit 3 is connected to the base of the transistor 4Tr of the bypass circuit 4.
　トランジスタ４Ｔｒは、アンチヒューズ素子３ＡＦを通じてベースから投入される電流の数百倍の電流を、コレクタ‐エミッタ間に発生させる。 The transistor 4Tr generates a current several hundred times as large as the current input from the base through the antifuse element 3AF between the collector and the emitter.
　抵抗３Ｒ1は、ＬＥＤ素子１両端にかかる電圧を、アンチヒューズ素子３ＡＦと分圧することで、アンチヒューズ素子３ＡＦを安定して作動させ、アンチヒューズ素子３ＡＦの作動後には、アンチヒューズ素子３ＡＦの通電電流を抑制する機能を有する。 The resistor 3R 1 divides the voltage applied to both ends of the LED element 1 with the antifuse element 3AF, thereby stably operating the antifuse element 3AF. After the antifuse element 3AF is activated, the antifuse element 3AF is energized. It has a function of suppressing current.
　抵抗３Ｒ2は、トランジスタ４Ｔｒの破壊を防止する機能を有する。 The resistor 3R 2 has a function of preventing the transistor 4Tr from being destroyed.
　本実施形態においては、電源（図示せず）に、１Ａの定電流電源（電圧の上限は２０Ｖ以上）を用いた。また、抵抗３Ｒ1に３３０Ωの抵抗素子を、抵抗３Ｒ2に１０Ωの抵抗素子をそれぞれ用いた。さらに、トランジスタ４Ｔｒに、ベース‐エミッタ間の電圧が０．６Ｖで、１ｍＡの電流がベース‐エミッタ間に流れるものを用いた。 In the present embodiment, a 1 A constant current power source (the upper limit of the voltage is 20 V or more) is used as a power source (not shown). A resistance element of 330Ω was used for the resistor 3R 1, and a resistance element of 10Ω was used for the resistor 3R 2 . Further, a transistor 4Tr having a base-emitter voltage of 0.6 V and a current of 1 mA flowing between the base and emitter was used.
　本実施形態の発光回路１００のアンチヒューズ回路２は、次のように作動する。 The antifuse circuit 2 of the light emitting circuit 100 of the present embodiment operates as follows.
　まず、ＬＥＤ素子１が正常に作動している場合には、たとえばＬＥＤ素子１のＶＦ値を３Ｖとすると、アンチヒューズ素子３ＡＦ（数ＭΩ）と抵抗３Ｒ1（３３０Ω）とで３Ｖの電圧が分圧されるが、ほぼ全ての電圧がアンチヒューズ素子３ＡＦ側に印加される。この時、アンチヒューズ素子３ＡＦにはわずかにリーク電流が発生するが、トランジスタ４Ｔｒのベース‐エミッタ間の抵抗と比べると抵抗３Ｒ1の抵抗の方が低いので、このリーク電流は抵抗３Ｒ1側に流れる。そのため、トランジスタ４Ｔｒはオン状態にはならず、コレクタ‐エミッタ間に電流はほとんど流れない。 First, when the LED element 1 is operating normally, for example, if the VF value of the LED element 1 is 3V, a voltage of 3V is divided by the antifuse element 3AF (several MΩ) and the resistor 3R 1 (330Ω). Almost all voltages are applied to the antifuse element 3AF side. At this time, although a slight leak current is generated in the anti-fuse element 3AF, the base of the transistor 4Tr - because people as compared with the resistance between the emitter of the resistor resistance 3R 1 is low, the leakage current through the resistor 3R 1 side Flowing. Therefore, the transistor 4Tr is not turned on and almost no current flows between the collector and the emitter.
　一方、ＬＥＤ素子１がオープン故障となり、このＬＥＤ素子１の両端に２０Ｖ以上の電圧が印加された場合、アンチヒューズ素子３ＡＦにもほぼ同等の２０Ｖ以上の電圧が印加される。アンチヒューズ素子３ＡＦは、２０Ｖ以上の電圧が印加されると作動し、不可逆に低抵抗化（数Ω）する。その結果、トランジスタ４Ｔｒのベース‐エミッタ間に印加される電圧が増大し、トランジスタ４Ｔｒがオン状態になるので、ベースに投入された電流量に応じて、コレクタ‐エミッタ間電流が発生し、ベース電流とコレクタ‐エミッタ間電流の和が１Ａ（電源の最大電流量）となるように、両者の電流量が調整される。本実施形態においては、アンチヒューズ素子３ＡＦに通電する電流量が約８．６ｍＡ、コレクタ‐エミッタ間電流が約９９０ｍＡであり、ＬＥＤ素子１の両端電圧は１．１８Ｖであった。 On the other hand, when the LED element 1 becomes an open failure and a voltage of 20 V or more is applied to both ends of the LED element 1, a substantially equivalent voltage of 20 V or more is also applied to the antifuse element 3AF. The anti-fuse element 3AF operates when a voltage of 20 V or more is applied, and irreversibly lowers the resistance (several Ω). As a result, the voltage applied between the base and the emitter of the transistor 4Tr increases and the transistor 4Tr is turned on, so that a collector-emitter current is generated according to the amount of current supplied to the base, and the base current And the collector-emitter current are adjusted so that the sum of the current between the collector and the emitter becomes 1 A (maximum current amount of the power supply). In the present embodiment, the amount of current flowing through the antifuse element 3AF is about 8.6 mA, the collector-emitter current is about 990 mA, and the voltage across the LED element 1 is 1.18V.
　アンチヒューズ素子３ＡＦには、たとえば、図２（Ａ）、（Ｂ）に示す構造からなるアンチヒューズ素子１３ＡＦを用いることができる。ただし、図２（Ａ）は、アンチヒューズ素子１３ＡＦを示す平面図、図２（Ｂ）は図２（Ａ）の矢印Ｘ‐Ｘ部分の断面図である。（図２（Ａ）、（Ｂ）においては、便宜上、アンチヒューズ素子を示す符号を「１３ＡＦ」とした。）
　アンチヒューズ素子１３ＡＦは、絶縁体薄膜層２１と、その両面に形成された下部電極層２２および上部電極層２３とを基本要素とする。そして、過電圧が印加されると、発熱により、絶縁体薄膜層２１の絶縁が破壊されるとともに、下部電極層２２および上部電極層２３とが溶融し、下部電極層２２および上部電極層２３とが融着して電気的に接続され、不可逆に低抵抗化するものである。以下、アンチヒューズ素子１３ＡＦの、より具体的な構造について説明する。 As the antifuse element 3AF, for example, an antifuse element 13AF having a structure shown in FIGS. 2A and 2B can be used. However, FIG. 2A is a plan view showing the antifuse element 13AF, and FIG. 2B is a cross-sectional view taken along the line XX in FIG. (In FIGS. 2A and 2B, for the sake of convenience, the reference numeral indicating the antifuse element is “13AF”.)
The antifuse element 13AF has an insulating thin film layer 21, and a lower electrode layer 22 and an upper electrode layer 23 formed on both surfaces thereof as basic elements. When an overvoltage is applied, the insulation of the insulator thin film layer 21 is broken due to heat generation, the lower electrode layer 22 and the upper electrode layer 23 are melted, and the lower electrode layer 22 and the upper electrode layer 23 are It is fused and electrically connected to irreversibly reduce the resistance. Hereinafter, a more specific structure of the antifuse element 13AF will be described.
　アンチヒューズ素子１３ＡＦは、基板２４を備える。基板２４には、たとえばＳｉ単結晶基板が用いられる。基板２４の表面には、絶縁性を確保するため、酸化物層２５が形成されている。酸化物層２５には、たとえばＳｉＯ2が用いられる。さらに、酸化物層２５上には、密着層２６が形成されている。密着層２６は、酸化物層２５と、次に説明する下部電極層２２との密着性を確保するためのものであり、たとえば次に説明する絶縁体薄膜層２１と同じ材質が用いられる。 The antifuse element 13AF includes a substrate 24. For the substrate 24, for example, a Si single crystal substrate is used. An oxide layer 25 is formed on the surface of the substrate 24 to ensure insulation. For example, SiO 2 is used for the oxide layer 25. Further, an adhesion layer 26 is formed on the oxide layer 25. The adhesion layer 26 is for ensuring adhesion between the oxide layer 25 and the lower electrode layer 22 to be described next. For example, the same material as the insulator thin film layer 21 to be described next is used.
　そして、密着層２６上に、下部電極層２２、絶縁体薄膜層２１、上部電極層２３が順に形成されている。下部電極層２２、上部電極層２３には、たとえばＰｔＡｕなどが用いられる。下部電極層２２、上部電極層２３の厚みは、たとえば１００～５００ｎｍ程度である。また、絶縁体薄膜層２１には、たとえば（Ｂａ、Ｓｒ）ＴｉＯ3（以下「ＢＳＴ」という）、ＳｒＴｉＯ3、ＢａＴｉＯ3、Ｐｂ（Ｚｒ，Ｔｉ）Ｏ3、ＳｒＢｉ4Ｔｉ4Ｏ15などが用いられる。絶縁体薄膜層２１の厚みは、たとえば５０～２００ｎｍ程度である。 A lower electrode layer 22, an insulator thin film layer 21, and an upper electrode layer 23 are formed in this order on the adhesion layer 26. For example, PtAu is used for the lower electrode layer 22 and the upper electrode layer 23. The thicknesses of the lower electrode layer 22 and the upper electrode layer 23 are, for example, about 100 to 500 nm. For the insulator thin film layer 21, for example, (Ba, Sr) TiO 3 (hereinafter referred to as “BST”), SrTiO 3 , BaTiO 3 , Pb (Zr, Ti) O 3 , SrBi 4 Ti 4 O 15 or the like is used. It is done. The thickness of the insulating thin film layer 21 is, for example, about 50 to 200 nm.
　そして、上部電極層２３上には、必要に応じて、上部絶縁層２７が形成されている。上部絶縁層２７は、上部電極層２３などからのリーク電流を低減するためのものであり、ここにも、たとえば絶縁体薄膜層２１と同じ材質が用いられる。 An upper insulating layer 27 is formed on the upper electrode layer 23 as necessary. The upper insulating layer 27 is for reducing leakage current from the upper electrode layer 23 and the like, and the same material as that of the insulating thin film layer 21 is used here, for example.
　そして、これらの上に、さらに、無機保護層２８、有機保護層２９が形成されている。無機保護層２８、有機保護層２９は、両者で、内部に水分が侵入するのを防ぐなどのために形成されたものであり、無機保護層２８には、たとえばＳｉＮX、ＳｉＯ2、Ａｌ2Ｏ3、ＴｉＯ2などが、有機保護層２９には、たとえばポリイミド樹脂、エポキシ樹脂などが用いられる。 And the inorganic protective layer 28 and the organic protective layer 29 are further formed on these. The inorganic protective layer 28 and the organic protective layer 29 are both formed to prevent moisture from entering the inside, and the inorganic protective layer 28 includes, for example, SiN x , SiO 2 , Al 2. For example, polyimide resin or epoxy resin is used for the organic protective layer 29, such as O 3 and TiO 2 .
　そして、下部電極層２２は、ビアホール３１ａ、引出電極３２ａを経由して外部電極３３ａに、上部電極層２３は、ビアホール３１ｂ、引出電極３２ｂを経由して外部電極３３ｂに引出されている。なお、引出電極３２ａ、３２ｂは有機保護層２９上に形成され、外部電極３３ａ、３３ｂは引出電極３２ａ、３２ｂ上に形成されている。 The lower electrode layer 22 is extracted to the external electrode 33a via the via hole 31a and the extraction electrode 32a, and the upper electrode layer 23 is extracted to the external electrode 33b via the via hole 31b and the extraction electrode 32b. The extraction electrodes 32a and 32b are formed on the organic protective layer 29, and the external electrodes 33a and 33b are formed on the extraction electrodes 32a and 32b.
　そして、外部電極３３ａ、３３ｂを外部に露出させて、全体に第２の有機保護層３０が形成されて、アンチヒューズ素子１３ＡＦは構成されている。第２の有機保護層３０にも、たとえばポリイミド樹脂、エポキシ樹脂などが用いられる。 Then, the external electrodes 33a and 33b are exposed to the outside, and the second organic protective layer 30 is formed on the whole to constitute the antifuse element 13AF. The second organic protective layer 30 is also made of, for example, polyimide resin or epoxy resin.
　かかる構造からなるアンチヒューズ素子１３ＡＦは、たとえば次の方法で製造される。なお、以下の説明において、各要素に用いる材質や材料は一例である。 The antifuse element 13AF having such a structure is manufactured, for example, by the following method. In the following description, the materials and materials used for each element are examples.
　まず、たとえば、表面にＳｉＯ2からなる酸化物層２５が形成された、ＳｉＯ2からなる基板２４を用意する。 First, for example, an oxide layer 25 made of SiO 2 formed on its surface, a substrate 24 made of SiO 2.
　次に、酸化物層２５上に、化学溶液堆積法（ＣＳＤ：Chemical　Solution　Deposition）で、ＢＳＴからなる密着層２６を形成する。具体的には、ＢＳＴを含む誘電体原料溶液をスピンコートにより塗布し、乾燥させ、加熱処理して形成する。 Next, an adhesion layer 26 made of BST is formed on the oxide layer 25 by chemical solution deposition (CSD). Specifically, a dielectric material solution containing BST is applied by spin coating, dried, and heat-treated.
　次に、密着層２６上に、スパッタリング法により、Ｐｔからなる下部電極層２２を形成する。 Next, the lower electrode layer 22 made of Pt is formed on the adhesion layer 26 by sputtering.
　次に、下部電極層２２上に、密着層２６と同様の方法で、ＢＳＴからなる絶縁体薄膜層２１を形成する。 Next, the insulator thin film layer 21 made of BST is formed on the lower electrode layer 22 by the same method as the adhesion layer 26.
　次に、絶縁体薄膜層２１上に、下部電極層２２と同様の方法で、Ｐｔからなる上部電極層２３を形成する。 Next, the upper electrode layer 23 made of Pt is formed on the insulator thin film layer 21 in the same manner as the lower electrode layer 22.
　次に、上部電極層２３上に、密着層２６や絶縁体薄膜層２１と同様の方法で、ＢＳＴからなる上部絶縁層２７を形成する。 Next, the upper insulating layer 27 made of BST is formed on the upper electrode layer 23 by the same method as the adhesion layer 26 and the insulating thin film layer 21.
　次に、上部絶縁層２７、上部電極層２３をエッチングして所定の形状とし、続いて絶縁体薄膜層２１、下部電極層２２、密着層２６をエッチングして所定の形状とする。なお、このとき、上部絶縁層２７、上部電極層２３には、ビアホール３１ａを通すための開口を設けておく。 Next, the upper insulating layer 27 and the upper electrode layer 23 are etched to have a predetermined shape, and then the insulating thin film layer 21, the lower electrode layer 22, and the adhesion layer 26 are etched to have a predetermined shape. At this time, the upper insulating layer 27 and the upper electrode layer 23 are provided with openings for passing the via holes 31a.
　次に、これらの積層構造に熱処理をおこなう。 Next, heat treatment is performed on these laminated structures.
　次に、これらの積層構造上に、プラズマ化学気相成長法（ＰＥＣＶＤ：Plasma　Enhanced　Chemical　Vapor Deposition）で、ＳｉＯXからなる無機保護層２８を形成する。 Next, an inorganic protective layer 28 made of SiO x is formed on these laminated structures by plasma enhanced chemical vapor deposition (PECVD).
　次に、無機保護層２８上に、ポリイミド樹脂からなる有機保護層２９を形成する。具体的には感光性ポリイミドをスピンコートし、露光、現像、キュアすることにより形成する。 Next, an organic protective layer 29 made of polyimide resin is formed on the inorganic protective layer 28. Specifically, it is formed by spin-coating photosensitive polyimide, exposing, developing, and curing.
　次に、有機保護層２９をマスクパターンとして利用し、ＣＨＦ3ガスを用いて無機保護層２８をパターニングする。このとき、開口を形成し、下側電極層２２および上側電極層２３をそれぞれ露出させておく。 Next, using the organic protective layer 29 as a mask pattern, the inorganic protective layer 28 is patterned using CHF 3 gas. At this time, an opening is formed and the lower electrode layer 22 and the upper electrode layer 23 are exposed.
　次に、無機保護層２８、有機保護層２９に形成された開口にビアホール３１ａ、３１ｂ、有機保護層２９上に引出電極３２ａ、３２ｂを形成する。具体的には、たとえば、マグネトロンスパッタを用いて、Ｔｉ層、Ｃｕ層を連続的に形成し、開口を埋めてビアホール３１ａ、３１ｂを形成するとともに、有機保護層２９上全面に金属膜を形成する。そして、その金属膜を、レジスト塗布、露光、現像によって形成したレジストパターンをマスクにして、イオンミリングを用いて所定のパターンにして引出電極３２ａ、３２ｂを形成する。 Next, via holes 31 a and 31 b are formed in the openings formed in the inorganic protective layer 28 and the organic protective layer 29, and extraction electrodes 32 a and 32 b are formed on the organic protective layer 29. Specifically, for example, a Ti layer and a Cu layer are continuously formed by using magnetron sputtering, the via holes 31a and 31b are formed by filling the openings, and a metal film is formed on the entire surface of the organic protective layer 29. . Then, extraction electrodes 32a and 32b are formed in a predetermined pattern using ion milling with the resist pattern formed by resist application, exposure and development as a mask.
　次に、開口により、引出電極３２ａ、３２ｂをそれぞれ部分的に露出させて、第２の有機保護層３０を形成する。具体的には、感光性樹脂材料をスピンコートで塗布し、露光、現像、キュアすることにより、エポキシ樹脂層を得る。 Next, the second organic protective layer 30 is formed by partially exposing the extraction electrodes 32a and 32b through the openings. Specifically, a photosensitive resin material is applied by spin coating, exposed, developed, and cured to obtain an epoxy resin layer.
　最後に、第２の有機保護層３０の開口から露出した引出電極３２ａ、３２ｂ上に、たとえば電解めっきにより、Ｎｉ層、Ａｕ層を順に形成し、外部電極３３ａ、３３ｂを形成して、アンチヒューズ素子１３ＡＦを完成させる。 Finally, an Ni layer and an Au layer are sequentially formed on the extraction electrodes 32a and 32b exposed from the opening of the second organic protective layer 30 by, for example, electroplating, and external electrodes 33a and 33b are formed. Element 13AF is completed.
　上述した構造からなり、上述した方法で製造し得るアンチヒューズ素子１３ＡＦは、１～１００ｎＦ程度と静電容量が大きく、静電気が印加されても、一時的に電荷を蓄えることができるため、作動しない。したがって、このアンチヒューズ素子１３ＡＦを、本実施形態にかかる発光回路１００のアンチヒューズ素子３ＡＦとして用いれば、ＬＥＤ素子１通電中（オープン故障となっていない状態）に静電気が印加されても、作動することがない。すなわち、静電気により誤作動することがない。 The antifuse element 13AF having the above-described structure and capable of being manufactured by the above-described method has a large capacitance of about 1 to 100 nF, and does not operate because it can temporarily store charges even when static electricity is applied. . Therefore, if this antifuse element 13AF is used as the antifuse element 3AF of the light emitting circuit 100 according to the present embodiment, it operates even when static electricity is applied while the LED element 1 is energized (in a state where no open failure occurs). There is nothing. That is, it does not malfunction due to static electricity.
　以上、第１実施形態にかかる発光回路１００について説明した。しかしながら、本発明が上記の内容に限定されることはなく、発明の主旨に沿って設計変更をなすことができる。たとえば、抵抗３Ｒ1、抵抗３Ｒ1の抵抗値、トランジスタ４Ｔｒの特性などは上記には限定されず、変更をなすことができる。また、使用するアンチヒューズ素子も、符号１３ＡＦとして示した構造のものには限定されず、過電圧により不可逆に低抵抗化するものであれば、他の構造のものも使用することができる。 The light emitting circuit 100 according to the first embodiment has been described above. However, the present invention is not limited to the above contents, and design changes can be made in accordance with the gist of the invention. For example, the resistance 3R 1 , the resistance value of the resistance 3R 1 , the characteristics of the transistor 4Tr, and the like are not limited to the above, and can be changed. Further, the antifuse element to be used is not limited to the structure shown by reference numeral 13AF, and other structures can be used as long as the resistance is irreversibly lowered by overvoltage.
　（第２実施形態）
　図３に、本発明の第２実施形態にかかる発光回路２００の回路図を示す。 (Second Embodiment)
FIG. 3 shows a circuit diagram of a light emitting circuit 200 according to the second embodiment of the present invention.
　発光回路２００では、２つのＬＥＤ素子１Ａと１Ｂとで１つのＬＥＤ素子群が構成され、このＬＥＤ素子群のそれぞれと並列に、アンチヒューズ回路２が接続されている。なお、アンチヒューズ回路２は、上述した第１実施形態にかかる発光回路１００で使用したものと同じものである。 In the light emitting circuit 200, two LED elements 1A and 1B constitute one LED element group, and an antifuse circuit 2 is connected in parallel with each of the LED element groups. The antifuse circuit 2 is the same as that used in the light emitting circuit 100 according to the first embodiment described above.
　発光回路２００においては、ＬＥＤ素子の総数に対して、使用するアンチヒューズ回路２の個数を１／２にすることができる。ただし、ＬＥＤ素子１Ａ、１Ｂのいずれか一方がオープン故障となった場合であっても、ＬＥＤ素子群として、ＬＥＤ素子１Ａ、１Ｂの両方が消灯する。もちろん、この場合においても、他のＬＥＤ素子群の点灯は維持できる。 In the light emitting circuit 200, the number of antifuse circuits 2 to be used can be halved with respect to the total number of LED elements. However, even if any one of the LED elements 1A and 1B has an open failure, both the LED elements 1A and 1B are turned off as the LED element group. Of course, even in this case, the lighting of the other LED element groups can be maintained.
１：ＬＥＤ素子
２：アンチヒューズ回路
３：検出回路（アンチヒューズ回路の一部）
３ＡＦ、１３ＡＦ：アンチヒューズ素子
３Ｒ1、３Ｒ2：抵抗
４：バイパス回路（アンチヒューズ回路の一部）
４Ｔｒ：トランジスタ
２１：絶縁体薄膜層
２２：下部電極層
２３：上部電極層
２４：基板
２５：酸化物層
２６：密着層
２７：上部絶縁層
２８：無機保護層
２９：有機保護層
３０：第２の有機保護層
３１ａ、３１ｂ：ビアホール
３２ａ、３２ｂ：引出電極
３３ａ、３３ｂ：外部電極 1: LED element 2: Antifuse circuit 3: Detection circuit (part of the antifuse circuit)
3AF, 13AF: anti-fuse element 3R 1, 3R 2: resistors 4: bypass circuit (part of the anti-fuse circuit)
4Tr: transistor 21: insulator thin film layer 22: lower electrode layer 23: upper electrode layer 24: substrate 25: oxide layer 26: adhesion layer 27: upper insulating layer 28: inorganic protective layer 29: organic protective layer 30: second Organic protective layers 31a, 31b: via holes 32a, 32b: extraction electrodes 33a, 33b: external electrodes

Claims (5)

  1. 　相互に並列に接続された、検出回路とバイパス回路とを備えたアンチヒューズ回路であって、
    　前記検出回路は、アンチヒューズ素子と、当該アンチヒューズ素子に直列に接続された抵抗素子を含み、
    　前記バイパス回路は、前記アンチヒューズ素子と前記抵抗素子との接続点に、ベースが接続されたトランジスタを含む、アンチヒューズ回路。     An antifuse circuit including a detection circuit and a bypass circuit connected in parallel to each other,
    The detection circuit includes an anti-fuse element and a resistance element connected in series to the anti-fuse element,
    The bypass circuit is an antifuse circuit including a transistor having a base connected to a connection point between the antifuse element and the resistance element.
  2. 　前記アンチヒューズ素子が、絶縁体薄膜層と、当該絶縁体薄膜層の両面にそれぞれ形成された下部電極層および上部電極層とを備え、過電圧が印加された場合に、前記絶縁体薄膜層の絶縁が破壊されるとともに、前記下部電極層と前記上部電極層とが溶融し、当該溶融した下部電極層と上部電極層とが融着して電気的に接続される、請求項１に記載されたアンチヒューズ回路。 The antifuse element includes an insulator thin film layer, and a lower electrode layer and an upper electrode layer formed on both surfaces of the insulator thin film layer, respectively, and insulates the insulator thin film layer when an overvoltage is applied. The lower electrode layer and the upper electrode layer are melted and the molten lower electrode layer and the upper electrode layer are fused and electrically connected to each other. Antifuse circuit.
  3. 　直列に接続された複数の発光素子を備えた発光回路であって、
    　前記発光素子のそれぞれと並列に、請求項１または２に記載されたアンチヒューズ回路が接続され、
    　前記アンチヒューズ回路の検出回路は、並列に接続された前記発光素子がオープン故障となった場合に、当該オープン故障を検出し、
    　前記発光素子がオープン故障となった状態を、前記検出回路が検出した場合に、前記アンチヒューズ回路のバイパス回路の前記トランジスタが導通する、発光回路。     A light-emitting circuit including a plurality of light-emitting elements connected in series,
    The antifuse circuit according to claim 1 or 2 is connected in parallel with each of the light emitting elements,
    The detection circuit of the antifuse circuit detects the open failure when the light emitting element connected in parallel has an open failure,
    A light emitting circuit in which the transistor of the bypass circuit of the antifuse circuit is turned on when the detection circuit detects a state in which the light emitting element has an open failure.
  4. 　直列に接続された複数の発光素子を備えた発光回路であって、
    　前記複数の発光素子は複数の発光素子群に区分され、
    　前記発光素子群のそれぞれと並列に、請求項１または２に記載されたアンチヒューズ回路が接続され、
    　前記アンチヒューズ回路の検出回路は、並列に接続された前記発光素子群の中の少なくとも１つの発光素子がオープン故障となった場合に、当該オープン故障を検出し、
    　前記発光素子がオープン故障となった状態を、前記検出回路が検出した場合に、前記アンチヒューズ回路のバイパス回路の前記トランジスタが導通する、発光回路。     A light-emitting circuit including a plurality of light-emitting elements connected in series,
    The plurality of light emitting elements are divided into a plurality of light emitting element groups,
    The antifuse circuit according to claim 1 or 2 is connected in parallel with each of the light emitting element groups,
    The detection circuit of the antifuse circuit detects the open failure when at least one light emitting element in the light emitting element group connected in parallel has an open failure,
    A light emitting circuit in which the transistor of the bypass circuit of the antifuse circuit is turned on when the detection circuit detects a state in which the light emitting element has an open failure.
  5. 　前記発光素子がＬＥＤ素子である、請求項３または４に記載された発光回路。 The light-emitting circuit according to claim 3 or 4, wherein the light-emitting element is an LED element.
PCT/JP2012/060108 2011-04-19 2012-04-13 Anti-fuse circuit and light emitting circuit WO2012144432A1 (en)

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