JP2013182930A - Laminated composite electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated composite electronic component which can integrally laminate a ceramic PTC thermistor and a ceramic capacitor without requiring a complicated manufacturing process and can achieve both countermeasures against overcurrent and removal of a high-frequency noise for a power supply line simultaneously.SOLUTION: A laminated composite electronic component includes: an element body in which a PTC thermistor part that has a semiconductor ceramic layer mainly composed of BaTiOand an internal electrode layer alternately laminated and a capacitor part that has an insulator layer mainly composed of BaTiOand the internal electrode layer alternately laminated are mutually laminated; signal external terminal electrodes 8a and 8b which are electrically connected to one end of an internal electrode layer 3 of the PTC thermistor part 4 and provided on both end parts of the element body 11; and a ground external terminal electrode 8c which is electrically connected to one end of an internal electrode layer 6 of the capacitor part 7 and formed over the bottom surface and side surface of the laminated capacitor part in the element body 11.

Description

  The present invention relates to a protective element that protects an electronic device or the like from overcurrent, noise, and the like. More specifically, the present invention relates to a multilayer composite electronic component in which a multilayer PTC thermistor and a multilayer capacitor are integrated.

As a thermistor, a PTC (Positive Temperature Coefficient) thermistor having a positive resistance temperature characteristic is known. This PTC thermistor increases in resistance to an increase in temperature. This PTC thermistor is used as a self-control heating element, an overcurrent protection element, a temperature sensor, and the like. Conventionally, as such a PTC thermistor, a semiconductor ceramic layer which is made conductive by adding a trace amount of rare earth elements to barium titanate (BaTiO ₃ ) as a main component, and a pair of external terminal electrodes sandwiching the semiconductor ceramic layer, A single plate type PTC thermistor provided with has been used.

  In recent years, especially for PTC thermistors used for overcurrent protection of power supply circuits, in order to reduce power consumption, it is strongly desired that the resistance at room temperature during non-operation (hereinafter referred to as “room temperature resistance” for convenience) be sufficiently small. It is rare. Since the room temperature resistance of the PTC thermistor is inversely proportional to the electrode area, the room temperature resistance can be reduced as the electrode area increases.

  In view of this, a multilayer PTC thermistor in which a plurality of semiconductor ceramic layers and a plurality of internal electrode layers are alternately stacked has been proposed as an alternative to the conventional single-plate PTC thermistor. In the stacked PTC thermistor, the electrode area can be greatly increased by stacking a plurality of internal electrode layers, so that the room temperature resistance can be reduced.

  Also, in a power supply circuit, if the voltage fluctuation in the power supply line becomes large due to the impedance existing in the power supply line or ground, the operation of the driving circuit becomes unstable or interference occurs between the circuits via the power supply circuit. Sometimes. Therefore, usually, a decoupling capacitor is connected between the power supply line and the ground.

In recent years, in communication devices such as mobile phones and information processing devices such as personal computers, the speed of signals has been increased in order to process a large amount of information, and the clock frequency of ICs used has been increased.
For this reason, noise containing a large amount of high frequency components is likely to occur, and in an IC power supply circuit, high frequency noise is usually absorbed using a multilayer ceramic capacitor having a high decoupling effect.

  As described above, the power supply line needs various countermeasures such as overcurrent protection and noise countermeasures, and requires separate countermeasure parts for each function.

  In the following Patent Document 1, a multilayer ceramic capacitor is provided with an overcurrent / overheat protection function by electrically connecting elements having PTC characteristics in series to one of a pair of external terminal electrodes provided on opposite side surfaces of the multilayer ceramic capacitor. A ceramic capacitor is disclosed.

  However, as a result of studies by the present inventors, in the multilayer composite element as shown in Patent Document 1 of the prior art, the PTC element surely generates heat during overcurrent or overheating due to a short circuit or the like, and the resistance increases. Although the multilayer ceramic capacitor can be protected, since the PTC element is connected in series to one of the external terminals of the multilayer ceramic capacitor and covered with the metal terminal, there is a problem that the manufacturing process becomes complicated and costs increase. In addition, with this structure, it is difficult to connect the multilayer ceramic capacitor and the PTC element to a configuration other than the series connection. Therefore, the multilayer ceramic capacitor absorbs high-frequency noise in the signal line or the power line, and the PTC element does A circuit configuration such as current protection cannot be realized.

Japanese Patent Laid-Open No. 11-176695

  The present invention has been made in view of such a situation, and an object thereof is to integrally laminate a multilayer PTC thermistor and a multilayer capacitor without requiring a complicated and expensive manufacturing process, and to prevent electronic devices and the like from overcurrent and noise. An object of the present invention is to provide a laminated composite electronic component that protects.

In order to achieve the above object, a multilayer composite electronic component according to the present invention includes a multilayer PTC thermistor portion in which a semiconductor ceramic layer mainly composed of BaTiO ₃ and internal electrode layers are alternately laminated, and BaTiO ₃ . One of the element main body in which the multilayer capacitor part in which the insulator layers as main components and the internal electrode layers are alternately laminated, and the internal electrode layer of the multilayer PTC thermistor part are opposite end faces of the element main body. And the other of the internal electrode layers of the laminated PTC thermistor portion is electrically connected to the other of the external terminal electrodes formed on the opposing end surface of the element body. One of the internal electrode layers of the multilayer capacitor portion is electrically connected to any one of the external electronic electrodes formed on the opposing end surfaces of the element body, and the multilayer capacitor A multilayer composite electronic component comprising: the other internal electrode layer electrically connected to an external terminal electrode formed on at least a bottom surface in a direction orthogonal to an opposing end surface of the element body. provide.

  In the multilayer composite electronic component according to the present invention, the other of the internal electrode layers of the multilayer capacitor portion is electrically connected to the external terminal electrode formed so as to straddle the bottom surface and the side surface in the direction orthogonal to the opposing end surface of the element body. May be connected.

  Furthermore, in the multilayer composite electronic component according to the present invention, the external terminal electrode formed on the opposing end surface of the element body may be a signal external terminal electrode.

  Furthermore, in the multilayer composite electronic component according to the present invention, the external terminal electrode formed on at least the bottom surface in the direction orthogonal to the opposing end surface of the element body may be a grounding external terminal electrode.

  In order to secure insulation between the laminated PTC thermistor portion and the ground, the grounding external terminal electrode needs to be formed so as not to contact the side surface of the semiconductor ceramic layer.

  The multilayer composite electronic component according to the present invention has the above-described structure, so that the multilayer PTC thermistor and the multilayer capacitor are juxtaposed and electrically connected in an L shape, and the multilayer is formed with respect to the power line. Since the PTC thermistor is arranged in series and the multilayer capacitor can be arranged between the power supply line and the ground, it is possible to reduce high frequency noise while protecting the electronic device and the like from overcurrent. In addition, since the multilayer composite electronic component according to the present invention has a three-terminal structure, an overcurrent flows into the element at the time of abnormality, and heat generated when the element generates heat can be efficiently released to the mounting board. As a result, the withstand voltage of the multilayer composite electronic component is improved.

It is explanatory drawing of the multilayer composite electronic component which concerns on one Embodiment of this invention, (a) is a perspective view, (b) is L1 sectional drawing, (c) is W1 sectional drawing. 1 is an electric circuit diagram of a multilayer composite electronic component according to an embodiment of the present invention. It is a disassembled perspective view which shows the structure of the lamination | stacking PTC thermistor part of the lamination | stacking type | mold composite electronic component which concerns on one Embodiment of this invention. It is a disassembled perspective view which shows the structure of the multilayer capacitor part of the multilayer composite electronic component which concerns on one Embodiment of this invention. (A) is the surface side perspective view of the multilayer composite electronic component which concerns on one Embodiment of this invention, (B) is the back surface (back surface) side perspective view of the multilayer composite electronic component shown to (A). It is explanatory drawing of the single laminated PTC thermistor which concerns on the comparative example of this invention, (a) is a perspective view, (b) is L2 sectional drawing, (c) is W2 sectional drawing. (A) is a voltage waveform when the multilayer composite electronic component according to one embodiment of the present invention is connected to the power supply line, and (B) is a voltage waveform when a single PTC thermistor is connected to the power supply line.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

As shown in FIG. 1, a multilayer composite electronic component 1 according to one embodiment of the present invention includes a semiconductor ceramic layer 2 mainly composed of BaTiO ₃ and a first internal electrode layer 3 (FIG. 1B, FIG. 1 (c)) alternately laminated PTC thermistor portions 4 (FIG. 1 (b), FIG. 1 (c)), and BaTiO ₃ as a main component, and a porosity equivalent to that of the semiconductor ceramic layer. Multilayer capacitor portion in which insulator layers 5 (FIGS. 1B and 1C) and second internal electrode layers 6 (FIGS. 1B and 1C) are alternately stacked 7 (FIG. 1 (b), FIG. 1 (c)) and a pair of signal external terminal electrodes 8a, 8b provided on both end surfaces of the element body 11 (FIG. 1 (1)). a), FIG. 1 (b)), and an external terminal for grounding formed over the bottom surface and side surface of the multilayer capacitor section 7 Electrode 8c (FIG. 1 (a), to FIG. 1 (b)) is a structure with. FIG. 1B is a cross-sectional view in the longitudinal direction of the multilayer composite electronic component, and FIG. 1C is a cross-sectional view in the short direction of the multilayer composite electronic component.
The multilayer PTC thermistor section 4 and the multilayer capacitor section 7 form an electric circuit as shown in FIG. 2, and the signal external terminal electrodes 8a as shown in FIGS. 5 (A) and 5 (B), 8b, and a three-terminal structure including an external terminal electrode 8c for grounding.

The semiconductor ceramic layer 2 and the insulator layer 5 are made of a material mainly composed of BaTiO ₃ . The first internal electrode layer 3 of the multilayer PTC thermistor portion 4 and the second internal electrode layer 6 of the multilayer capacitor portion 7 are made of, for example, nickel, palladium, an alloy containing at least one of these metals, or the like.

  Although the thickness of the semiconductor ceramic layer 2 is not specifically limited, For example, about 5-200 micrometers and the thickness of the 1st internal electrode layer 3 are not specifically limited, For example, what is necessary is just about 1-5 micrometers.

  The thickness of the insulator layer 5 is not particularly limited, but is about 5 to 200 μm, for example, and the thickness of the second internal electrode layer 6 is not particularly limited, but is about 1 to 5 μm, for example.

  External end electrodes 8a and 8b for signals are formed on the end faces of the element body 11 that face each other. In the laminated PTC thermistor section, the first internal electrode layers 3 that are alternately drawn out are respectively connected to the signal external terminals. It is connected to the terminal electrodes 8a and 8b. Furthermore, either one of the signal external terminal electrodes 8 a and 8 b is connected to one of the second internal electrodes 6 of the multilayer capacitor unit 7. On the other hand, the grounding external terminal electrode 8 c extends across the bottom surface and the side surface of the multilayer capacitor portion 7 of the element body 11 and is connected to the other of the second internal electrodes 6 of the multilayer capacitor portion 7. The signal external terminal electrodes 8a and 8b and the ground external terminal electrode 8c are made of, for example, Ag, Pd, Cu, Ni, Zn, Al, Sn, an alloy containing at least one of these metals, and the thickness thereof. Although it does not specifically limit, For example, it is about 5-30 micrometers. The signal external terminal electrodes 8a and 8b and the ground external terminal electrode 8c may be a single layer or may be a laminated film of a plurality of layers.

Next, a method for manufacturing the multilayer composite electronic component 1 will be described.
First, the slurry for semiconductor ceramic layer formation containing the raw material of the semiconductor ceramic layer 2 shown in FIG. 1 is prepared. Next, a slurry for forming a semiconductor ceramic layer is applied onto a PET (PET) film by a doctor blade method or the like and dried to produce a green sheet.

  Similarly, a slurry for forming an insulator layer containing a raw material for the insulator layer 5 shown in FIG. 1 is prepared. Next, the insulator layer forming slurry is applied onto a pet film by a doctor blade method or the like and dried to prepare a green sheet.

  The first internal electrode layer 3 of the multilayer PTC thermistor section 4 shown in FIG. 1 is formed on the surface of the semiconductor ceramic layer green sheet, and the second of the multilayer capacitor section 7 shown in FIG. The internal electrode paste for forming the internal electrode layer 6 is printed by screen printing or the like. Next, as shown in FIG. 3, the required number of semiconductor ceramic layer green sheets printed with the first internal electrode paste are laminated, and the internal electrode paste is printed on the upper and lower surfaces of the laminate. The laminated PTC thermistor portion 4 is formed by stacking the first cover sheets 9 each including a plurality of non-conducting ceramic ceramic green sheets.

  Similarly, as shown in FIG. 4, the required number of insulating layer green sheets printed with the second internal electrode paste are laminated, and the internal electrode paste is printed on the upper and lower surfaces of the laminate. The multilayer capacitor portion 7 is formed by stacking the second cover sheets 10 each including a plurality of non-insulator layer green sheets.

  Next, the laminated PTC thermistor part 4 and the laminated capacitor part 7 are laminated and the integrated laminated body is pressed and pressure-bonded in the laminating direction with a press to obtain a pressure-bonded body. The pressure-bonded body is cut with a cutter or the like to obtain a laminated chip having a size corresponding to the element body 11 shown in FIG.

Next, the laminated chip was heated and held in the atmosphere at 250 to 400 ° C. for 1 to 10 hours to remove the binder, and then laminated in an H ₂ / N ₂ atmosphere at 1150 to 1250 ° C. for 0.5 to 4 hours. The chip is sintered to obtain an element body (sintered body) 11.

  Subsequently, the element body 11 obtained is re-oxidized by heating and holding at 500 to 800 ° C. for 0.5 to 6 hours in the air. The PTC characteristic of the semiconductor ceramic layer 2 is expressed by the reoxidation treatment.

Subsequently, in order to form the signal external terminal electrodes 8a and 8b on both end faces of the obtained element body 11, an external terminal electrode paste is formed by dipping. Further, in order to form the grounding external terminal electrode 8c, an external terminal electrode paste is formed by screen printing on the bottom and side surfaces of the capacitor portion.

  Subsequently, the element body 11 on which the external terminal electrode paste is formed is baked at 500 to 700 ° C. in the atmosphere, and then solder plating is performed to obtain the multilayer composite electronic component 1 as shown in FIG.

  The signal external terminal electrodes 8a and 8b and the ground external terminal electrode 8c may be formed by a film forming method such as sputtering.

  The multilayer composite electronic component 1 of the present embodiment can integrally laminate a multilayer PTC thermistor and a multilayer capacitor without requiring a complicated and expensive manufacturing process. In addition, the multilayer composite electronic component 1 includes a multilayer PTC thermistor and a multilayer capacitor connected in parallel and electrically connected in an L shape to form a three-terminal structure. Since a multilayer capacitor can be placed between the power supply line and ground at the same time, high frequency noise can be reduced while protecting electronic equipment from overcurrent, resulting in the number of electrical circuit components. Reduction, space saving, and cost reduction. Furthermore, when an overcurrent flows into this multilayer composite electronic component and the multilayer PTC thermistor element generates heat, the heat can be efficiently released to the mounting board, so that it is more heated than when using a single PTC thermistor. As a result, the withstand voltage of the multilayer composite electronic component is improved.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

In the laminated PTC thermistor part, BaCO ₃ , TiO ₂ , Gd ₂ O ₃ and SiO ₂ were weighed so that the barium titanate compound obtained by sintering had the composition of the following formula (A), The mixture was placed in a nylon pot together with water and grinding balls, mixed for 6 hours, and dried to obtain a mixed powder.
(Ba _0.997 Gd _0.003 ) _1.02 TiO ₃ + 0.05SiO ₂ (A)

  The obtained mixed powder was temporarily molded, and this was held in the atmosphere at 1150 ° C. for 4 hours and calcined to obtain a calcined body. Next, the calcined powder obtained by pulverizing the calcined body is put into a nylon pot together with a solvent and a grinding ball, and a binder and a plasticizer are added thereto and mixed in a ball mill for 20 hours. A forming slurry was obtained.

  The obtained slurry for forming a semiconductor ceramic layer was applied onto a pet film by a doctor blade method and dried to prepare a green sheet. A Ni internal electrode was formed by printing the first internal electrode layer Ni paste on the surface of the green sheet by screen printing.

On the other hand, in the multilayer capacitor part, BaCO ₃ , TiO ₂ and SiO ₂ were weighed so that the barium titanate compound obtained by sintering had the composition of the following formula (B), and then purified water and pulverized The mixture was put in a nylon pot together with the balls, mixed for 6 hours, and dried to obtain a mixed powder.
Ba _1.02 TiO ₃ + 0.05SiO ₂ (B)

  The obtained mixed powder was temporarily molded, and this was held in the atmosphere at 1150 ° C. for 4 hours and calcined to obtain a calcined body. Next, the calcined powder obtained by pulverizing this calcined body is put into a nylon pot together with a solvent and a grinding ball, and a binder and a plasticizer are added thereto and mixed in a ball mill for 20 hours. A forming slurry was obtained.

  The obtained insulator layer forming slurry was applied onto a pet film by a doctor blade method and dried to prepare a green sheet. A second internal electrode Ni paste was printed on the surface of the green sheet by screen printing to form a Ni internal electrode.

  In the laminated PTC thermistor portion, as shown in FIG. 3, the green sheets are alternately exposed such that one end face of the alternately laminated first internal electrode layers is exposed at the left end portion of the semiconductor ceramic layer and the other is at the right end portion. Were laminated. On the other hand, in the multilayer capacitor portion, as shown in FIG. 4, one end surface of the second internal electrode layer is alternately exposed to the left end portion of the insulator layer, and the other is exposed to the side surface portion orthogonal thereto. Were laminated. Furthermore, the laminated PTC thermistor part and the laminated capacitor part were laminated, and this was pressed and pressure-bonded in the laminating direction with a press. The pressure-bonded body was cut with a cutter to obtain a 2.0 mm × 1.2 mm × 1.2 mm composite laminated chip.

The laminated body was heated and held at 300 ° C. for 8 hours in the air to remove the binder, and then the laminated body was sintered at 1200 ° C. for 2 hours in an H ₂ / N ₂ atmosphere to obtain the element body (sintered body). Obtained. Subsequently, the obtained device main body was heated and maintained at 700 ° C. for 2 hours in the atmosphere to perform reoxidation treatment.

Subsequently, an Ag paste is applied across the both end faces of the element body, the bottom face of the capacitor portion, and the side face perpendicular to the both end faces, and then baked at 600 ° C. in the atmosphere to external terminal electrodes (signal external terminal electrodes and grounding terminals). External terminal electrode) was formed. About the multilayer composite electronic component 1 having the structure shown in FIG. 1 thus obtained, a resistance value at 25 ° C. (R25 ° C., unit: Ω) and a resistance value at 200 ° C. (R200 ° C., unit: Ω) Each was measured with a digital multimeter. Furthermore, PTC jump {[log 10 (R200 ° C / R25 ° C)], unit: digit} was determined from the measured values of the resistance value at 25 ° C (R25 ° C) and the resistance value at 200 ° C (R200 ° C). Also, the multilayer composite electronic component 1 soldered on the printed circuit board is placed in a thermostatic chamber at 25 ° C., a DC power supply is connected between the signal external terminal electrodes on both end faces, and the applied voltage is gradually increased from 0V. The voltage was increased until the multilayer composite electronic component 1 was destroyed, and the voltage immediately before the destruction was determined as the withstand voltage. In addition, the number of samples used for the measurement is 20 each, and Table 1 shows an average value of the measurement results.

By the method shown in the comparative example, a laminated PTC thermistor was produced by itself as shown in FIG. 5, and the same evaluation was performed. The external terminal has a two-terminal structure having only signal external electric terminal electrodes on both end faces. 5A is a perspective view of a single laminated PTC thermistor, FIG. 5B is a longitudinal sectional view of the single laminated PTC thermistor, and FIG. 5C is a short sectional view of the single laminated PTC thermistor. is there.

  As is clear from the measurement results shown in Table 1, the R25 ° C. and the PTC jump of both are the same value, but the multilayer composite electronic component shown in the example is more single unit shown in the comparative example. The withstand voltage was higher than that of the laminated PTC thermistor. This is presumably because the laminated composite electronic component was able to efficiently release Joule heat generated by voltage application to the mounting substrate and to increase the voltage leading to thermal runaway.

  Further, when the laminated composite electronic component shown in the example and the single laminated PTC thermistor shown in the comparative example were connected to the power supply line and energized and the electric signal was observed with an oscilloscope, the laminated composite electronic component shown in FIG. The signal waveform of the type composite electronic component shows that the spike noise is reduced as compared with the case where a single PTC thermistor is connected to the power supply line.

DESCRIPTION OF SYMBOLS 1 Laminated composite electronic component 2 Semiconductor ceramic layer 3 1st internal electrode 4 Laminated PTC thermistor part 5 Insulator layer 6 2nd internal electrode 7 Laminated capacitor part 8a, 8b Signal external terminal electrode 8c Grounding external terminal electrode 9 First cover sheet 10 Second cover sheet 11 Element body 12 Single layered PTC thermistor

Claims (4)

A laminated PTC thermistor portion in which semiconductor ceramic layers mainly composed of BaTiO ₃ and internal electrode layers are alternately laminated, and an insulator layer and internal electrode layers mainly composed of BaTiO ₃ are alternately laminated. One of the element body in which the multilayer capacitor part is laminated and one of the internal electrode layers of the multilayer PTC thermistor part is electrically connected to one of the external terminal electrodes formed on the opposing end surfaces of the element body, and the laminated PTC The other of the internal electrode layers of the thermistor part is electrically connected to the other of the external terminal electrodes formed on the opposing end face of the element body, and one of the internal electrode layers of the multilayer capacitor part faces the element body. One of the external terminal electrodes formed on the end face is electrically connected, and the other of the internal electrode layers of the multilayer capacitor section is orthogonal to the opposing end face of the element body At least the multilayer composite electronic component, which is a bottom surface formed external terminal electrodes electrically connected to each of the direction.   The other of the internal electrode layers of the multilayer capacitor portion is electrically connected to an external terminal electrode formed so as to straddle a bottom surface and a side surface in a direction orthogonal to the opposing end surface of the element body. The multilayer composite electronic component according to claim 1.   2. The multilayer composite electronic component according to claim 1, wherein the external terminal electrodes formed on opposing end faces of the element body are signal external terminal electrodes. 3.   2. The multilayer composite electronic component according to claim 1, wherein the external terminal electrode formed on at least the bottom surface in a direction orthogonal to the opposing end surface of the element body is a grounding external terminal electrode.

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