JP2007141884A - Electronic component and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component in which occurrence of mutual diffusion can be controlled, while realizing miniaturization as compared with prior art, and to provide its manufacturing method. <P>SOLUTION: The electronic component E1 comprises an insulator 10 and a varistor element 20. The varistor element 20 has a varistor layer that expresses voltage nonlinearity, and a pair of varistor electrodes 22 and 24 located to sandwich the varistor layer. The insulator 10 is bonded to the varistor element 20 and is provided with first and second internal conductors 12 and 14. The sintering temperature of a material constituting the insulator 10 is set lower than that of a material constituting the varistor layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic component for protecting an electronic device from a high voltage due to static electricity or the like, and a manufacturing method thereof.

As this type of electronic component, an electronic component in which an inductor and a varistor are formed inside a ceramic sintered body is known (for example, see Patent Document 1). Such a conventional electronic component is manufactured by laminating a plurality of ceramic layers each formed with a conductor pattern and a varistor electrode pattern, followed by pressure bonding and firing. That is, in the conventional electronic component, the inductor portion including the inductor and the varistor portion including the varistor are formed by simultaneous firing.
JP 2004-311877 A

  By the way, in order to reduce the capacitance component due to the inductor itself and prevent high-speed signal deterioration, it is generally preferable that the dielectric constant of the inductor portion including the inductor is lower than the dielectric constant of the varistor portion including the varistor. .

  However, when the characteristics of the inductor part and the varistor part are not approximate, if the inductor part and the varistor part are simultaneously fired as described above, mutual diffusion occurs near the interface between the inductor part and the varistor part. End up. In such a region where mutual diffusion occurs, the composition changes and the dielectric constant becomes high, so that the inductor cannot be disposed in that region. Therefore, the conventional electronic component has a problem that it is difficult to reduce the size because it is necessary to form the inductor portion thicker in the vicinity of the interface between the inductor portion and the varistor portion in consideration of mutual diffusion.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an electronic component that can suppress the occurrence of mutual diffusion and can be made smaller than before and a method for manufacturing the same.

  An electronic component according to the present invention includes a varistor element including a varistor layer including a varistor layer that expresses voltage nonlinearity and a pair of varistor electrodes positioned so as to sandwich the varistor layer, and the varistor element is fixed to the varistor element. And an insulator provided with an inductor, wherein a sintering temperature of a material constituting the insulator is lower than a sintering temperature of a material constituting the varistor layer.

  In the electronic component according to the present invention, the sintering temperature of the material constituting the insulator is lower than the sintering temperature of the material constituting the varistor layer. Therefore, by forming the varistor element body and subsequently firing the material constituting the insulator at a temperature lower than the sintering temperature of the material constituting the varistor element body, the vicinity of the interface between the insulator and the varistor element body Almost no interdiffusion occurs. As a result, since it is not necessary to form a thick insulator in consideration of mutual diffusion, it is possible to reduce the size of the electronic component as compared with the related art.

  Further, the device further includes a first terminal electrode, a second terminal electrode, and a third terminal electrode respectively formed on the side surfaces of the insulator and the varistor element body, and the insulators are coupled to each other by polarity inversion, Having a first inner conductor and a second inner conductor, one end of the first inner conductor is connected to the first terminal electrode, and one end of the second inner conductor is connected to the second terminal electrode The other end of the first inner conductor and the other end of the second inner conductor are connected, and one of the pair of varistor electrodes is connected to a connection point between the first inner conductor and the second inner conductor, The other of the pair of varistor electrodes is preferably connected to the third terminal electrode. In this way, it is possible to cancel the influence of the stray capacitance component by appropriately setting the induction coefficient of the inductor with respect to the stray capacitance component of the varistor. As a result, an input impedance with a flat frequency characteristic can be realized over a wide band.

  The insulator is preferably made of a material having a lower dielectric constant than the material constituting the varistor layer. In this way, the dielectric constant around the inductor can be lowered, and the capacitance component by the inductor itself can be reduced, so that the characteristics of the inductor can be improved.

  Further, it is preferable that the insulator includes glass as a main component and the inductor includes silver as a main component. In this case, since the insulator contains glass as a main component, the dielectric constant of the insulator can be made extremely low, and the varistor element adheres well to the varistor element during sintering. Interdiffusion can be extremely suppressed. In addition, since the inductor contains silver as a main component, the direct current resistance can be reduced, and transmission characteristics can be improved.

  The insulator and the varistor layer preferably each contain ZnO. In this case, since the characteristics of the insulator and the varistor element body are approximated, mutual diffusion is less likely to occur near the interface between the insulator and the varistor element body.

  On the other hand, in the method for manufacturing an electronic component according to the present invention, a pair of electrode patterns serving as varistor electrodes are arranged so as to sandwich a varistor green sheet serving as a varistor layer that exhibits voltage nonlinearity, and the varistor green sheet and the electrode pattern are arranged. Are laminated together and fired to produce a varistor element body having a varistor, a step of alternately printing and laminating an insulator green layer and a conductor pattern serving as an inductor on the varistor element body, insulation Firing the body green layer and the conductor pattern at a temperature lower than the sintering temperature of the material constituting the varistor green sheet to produce an insulator having an inductor.

  In the method for manufacturing an electronic component according to the present invention, an insulator green layer and a conductor pattern are alternately printed and laminated on a varistor element body produced by sintering a varistor green sheet. Then, the insulator green layer and the conductor pattern are baked at a temperature lower than the sintering temperature of the material constituting the varistor green sheet to generate an insulator. Therefore, since the insulator and the varistor element body are separately fired, mutual diffusion hardly occurs in the vicinity of the interface between the insulator and the varistor element body. As a result, it is not necessary to print an extra insulating layer in consideration of mutual diffusion, and the electronic component can be made smaller than before.

  The insulator green layer is preferably made of a material having a lower dielectric constant than the material constituting the varistor green sheet. In this way, the dielectric constant around the inductor can be lowered, and the capacitance component by the inductor itself can be reduced, so that the characteristics of the inductor can be improved.

  Moreover, it is preferable that an insulator green layer contains a glass component as a main component, and a conductor pattern contains silver as a main component. In this way, since the insulator green sheet contains a glass component, the dielectric constant of the insulator formed by sintering the insulator green layer can be lowered, and the insulator green layer is sintered. In this case, the insulator and the varistor element body are sufficiently fixed by being familiar with the varistor element. Moreover, since the conductor pattern contains silver as a main component, the direct current resistance of the inductor can be reduced, and the transmission characteristics can be improved.

  The insulator green layer and the varistor green sheet preferably each contain ZnO. In this case, since the characteristics of the insulator formed by sintering the insulator green layer and the varistor element body generated by sintering the varistor green sheet approximate, the insulator and varistor element Interdiffusion is less likely to occur in the vicinity of the interface.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to suppress generation | occurrence | production of mutual diffusion, the electronic component which can aim at size reduction compared with the past, and its manufacturing method can be provided.

  Preferred embodiments of the present invention will be described with reference to the drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and a duplicate description is omitted.

(First embodiment)
With reference to FIGS. 1-3, the structure of the electronic component E1 which concerns on 1st Embodiment is demonstrated. FIG. 1 is a perspective view showing the inside of the electronic component according to the first embodiment. FIG. 2 is an exploded perspective view for explaining the configuration of the varistor element body included in the electronic component according to the first embodiment.

  The electronic component E1 is for protecting the electronic device from a high voltage due to static electricity or the like. The electronic component E1 includes an insulator 10, a varistor element body 20, a first terminal electrode 30, a second terminal electrode 32, a third terminal electrode 34, and an external conductor 36, and the insulator 10 and the varistor element body. 20 is produced by firing separately (details will be described later).

  The insulator 10 is made of glass, and is formed by a printing lamination method in which glass paste is screen-printed and sequentially laminated as will be described later. For this reason, the insulator 10 exhibits the characteristics of having a low dielectric constant and electrical insulation.

  The insulator 10 has a first inner conductor 12 and a second inner conductor 14 that are coupled to each other with the polarity reversed. The first and second inner conductors 12 and 14 are covered with the insulator 10 and are electrically insulated from each other, and each constitutes an inductor. One end of the first inner conductor 12 is drawn out to one end face of the insulator 10 (an end face on which the first terminal electrode 30 is formed), and is connected to the first terminal electrode 30. One end of the second inner conductor 14 is drawn out to the other end surface of the insulator 10 (the end surface on which the second terminal electrode 32 is formed), and is connected to the second terminal electrode 32. The other ends of the first and second terminal electrodes 12 and 14 are both drawn out to the same side surface (side surface on which the external conductor 36 is formed) of the insulator 10 and connected to the external conductor 36, respectively. That is, the first terminal electrode 12 and the second terminal electrode 14 are electrically connected via the external conductor 36.

  The first inner conductor 12 and the second inner conductor 14 include regions 12 a and 14 a that overlap each other when viewed from the stacking direction of the insulator 10. The first inner conductor 12 and the second inner conductor 14 are capacitively coupled in the regions 12a and 14a. The first and second inner conductors 12 and 14 are sintered at a temperature substantially equal to a sintering temperature (about 800 ° C. to 900 ° C.) when the insulator 10 made of glass is generated and has a resistivity. Ag is preferably used as the main component.

  As shown in FIG. 2, the varistor element body 20 includes a plurality (four in the first embodiment) of varistor green sheets A2 and A3 each having a first varistor electrode 22 and a second varistor electrode 24 formed thereon. The varistor green sheets A1 to A4 are laminated. The actual varistor element body 20 is integrated to such an extent that the boundaries between the varistor green sheets A1 to A4 cannot be visually recognized. The varistor green sheets A1 to A4 function as a varistor layer that develops voltage nonlinearity when fired.

  The varistor green sheets A1 to A4 are made of a ceramic material mainly composed of ZnO. This ceramic material further contains, as an additive, at least one element selected from the group consisting of rare earths and Bi, Co. Here, since the varistor green sheets A1 to A4 contain Co in addition to the rare earth, the varistor green sheets A1 to A4 have excellent voltage nonlinear characteristics, that is, varistor characteristics, and also have a high dielectric constant. The ceramic material constituting the varistor green sheets A1 to A4 may further contain Al as an additive. When Al is included, the varistor green sheets A1 to A4 have low resistance. The rare earth contained as an additive is preferably Pr.

  These metal elements can exist in the form of simple metals or oxides in the varistor green sheets A1 to A4. The varistor green sheets A1 to A4 may further include metal elements other than those described above as additives (for example, Cr, Ca, Si, K, etc.) for the purpose of further improving the characteristics. Good.

  A first varistor electrode 22 is formed on the surface of the varistor green sheet A2. The first varistor electrode 22 has a straight line type pattern and extends along the short direction of the varistor green sheet A2. One end of the first varistor electrode 22 is drawn out to one side of the varistor green sheet A2 so as to be exposed on the side surface of the element body 1 (side surface on which the external conductor 36 is formed). The other end of the first varistor electrode 22 is not exposed on the side surface (the side surface on which the third terminal electrode 34 is formed) of the varistor element body 20 and is in a position drawn from the side surface. One end of the first varistor electrode 22 is connected to an external conductor 36 formed on the side surface of the varistor element body 20. Therefore, the other end of the first inner conductor 12, the other end of the second inner conductor 14, and one end of the first varistor electrode 22 are electrically connected via the outer conductor 36.

  A second varistor electrode 24 is formed on the surface of the varistor green sheet A3. The second varistor electrode 24 has a straight line pattern and extends along the short direction of the varistor green sheet A3. One end of the second varistor electrode 24 is drawn out to one side of the varistor green sheet A3 so as to be exposed on the side surface of the varistor element body 20 (the side surface on which the third terminal electrode 34 is formed). The other end of the second varistor electrode 24 is not exposed to the side surface (side surface on which the external conductor 36 is formed) of the varistor element body 20 and is in a position drawn from the side surface. One end of the second varistor electrode 24 is connected to a third terminal electrode 34 formed on the side surface of the varistor element body 20.

  The first varistor electrode 22 and the second varistor electrode 24 include regions 22a and 24a that overlap each other when viewed from the stacking direction of the varistor green sheets A1 to A4. Therefore, the region 22a of the first varistor electrode 22, the region 24a of the second varistor electrode 24, and the region where the region 22a of the first varistor electrode 22 and the region 24a of the second varistor electrode 24 overlap in the varistor green sheet A2. One varistor 62 is formed. The first varistor electrode 22 and the second varistor electrode 24 are preferably made of Pd or an Ag—Pd alloy.

  The first terminal electrode 30, the second terminal electrode 32, the third terminal electrode 34, and the outer conductor 36 are arranged such that the first and second inner conductors 12 and 14 made of Ag are not melted. It is preferable that the metal material be formed at a temperature lower than the melting point of the two inner conductors 12 and 14. This metal material has good electrical connectivity with metals such as Ag and Pd constituting the first and second inner conductors 12 and 14 and the first and second varistor electrodes 22 and 24. Moreover, Ag having good adhesion to the end surfaces of the insulator 10 and the varistor element body 20 is preferable. The first terminal electrode 30 functions as an input terminal electrode of the electronic component E1, the second terminal electrode 32 functions as an output terminal electrode of the electronic component E1, and the third terminal electrode 34 is a ground of the electronic component E1. Functions as a terminal electrode.

  On the surfaces of the first terminal electrode 30, the second terminal electrode 32, the third terminal electrode 34, and the outer conductor 36, a Ni plating layer (not shown), a Sn plating layer (not shown), and the like are sequentially formed. Yes. These plating layers are formed mainly for the purpose of improving solder heat resistance and solder wettability when the electronic component E1 is mounted on a substrate or the like by solder reflow.

  Next, based on FIG.3 and FIG.4, the circuit structure of the electronic component E1 which has the structure mentioned above is demonstrated. FIG. 3 is a diagram for explaining a circuit configuration of the electronic component according to the first embodiment. FIG. 4 is a diagram showing an equivalent circuit of the circuit configuration shown in FIG.

  As described above, the first and second inner conductors 12 and 14 include regions 12a and 14a that overlap each other when viewed from the stacking direction of the insulator 10, and are capacitively coupled in the regions 12a and 14a. Yes. Therefore, the electronic component E1 has a capacitive component 60 formed by the first inner conductor 12 and the second inner conductor 14, as shown in FIG. The capacitive component 60 is connected between the first terminal electrode 30 and the second terminal electrode 32.

  Here, “polarity reversal coupling” means that the winding start of the inductance component corresponding to the first inner conductor 12 is the first terminal electrode 30 side, as shown in FIG. When the start of winding of the corresponding inductance component is on the side connected to the first inner conductor 12 (in the first embodiment, on the outer conductor 36 side), the first inner conductor 12 and the second inner conductor 14 are connected. This means that the bond with is positive. That is, the “polarity reversal coupling” means that a current flows into the first inner conductor 12 from the first terminal electrode 30 side and the second inner conductor 14 is connected to the first inner conductor 12 (this embodiment). In FIG. 5, current flows from the outer conductor 36 side), and the magnetic flux generated in the first inner conductor 12 and the magnetic flux generated in the second inner conductor 14 are strengthened.

  In the electronic component E1, the first varistor electrode 22, the second varistor electrode 24, and the portion sandwiched between the regions 22a and 24a of the first and second varistor electrodes 22 and 24 in the varistor green sheet A2 A varistor 62 is formed. As shown in FIG. 3, the varistor 62 is connected between a connection point (outer conductor 36) between the first inner conductor 12 and the second inner conductor 14 and the third terminal electrode 34.

  The first and second inner conductors 12 and 14 that are coupled to each other with the polarity reversed are converted into a first inductance component 64, a second inductance component 66, and a third inductance component 68, as shown in FIG. can do. The first inductance component 64 and the second inductance component 66 are connected in series between the first terminal electrode 30 and the second terminal electrode 32. The third inductance component 68 is connected between a connection point between the first inductance component 64 and the second inductance component 66 connected in series and the varistor 62. When the induction coefficient of the first and second inner conductors 12 and 14 is Lz, and the coupling coefficient between the first and second inner conductors 12 and 14 is Kz, the first inductance component 64 and the second inductance component. The induction coefficient of 66 is (1 + Kz) Lz, and the induction coefficient of the third inductance component 68 is -KzLz.

  As shown in FIG. 4, the varistor 62 can be converted into a variable resistor 70 and a stray capacitance component 72 that are connected in parallel between the third inductance component 68 and the third terminal electrode 36. The variable resistor 70 normally has a large resistance value, and the resistance value decreases when a high voltage surge is applied. In the varistor 62, a high-speed signal with a small amplitude can be approximated only by the stray capacitance component 72.

The input impedance Zin of the electronic component E1 shown in FIG. 4 is expressed by the following equation (1). Here, the capacitance of the capacitance component 60 is Cs, and the capacitance of the stray capacitance component 72 of the varistor 62 is Cz.

上記（２）式及び（３）式からも分かるように、第１及び第２の内部導体１２，１４間の結合係数Ｋｚを任意に選べるため、柔軟性の高い回路設計が可能となる。 In the equation (1), if the capacitance Cs of the capacitance component 60 is set so as to satisfy the following equation (2), the input impedance Zin does not depend on the frequency characteristics. When the capacitance Cs of the capacitive component 60 is set to the following formula (2) and the induction coefficient Lz of each internal conductor is set as shown in the following formula (3), the input impedance Zin is matched with the characteristic impedance Zo. Can do.

As can be seen from the above equations (2) and (3), the coupling coefficient Kz between the first and second inner conductors 12 and 14 can be arbitrarily selected, so that a highly flexible circuit design is possible.

  Therefore, according to the present embodiment, it is possible to provide an electronic component E1 that is excellent in impedance matching even for high-speed signals while protecting a semiconductor device or the like from high-voltage static electricity.

  Incidentally, the varistor 62 also includes a stray inductance component 74 as shown in FIG. Normally, the resistance value of the variable resistor 70 is large, and the resistance value decreases when a high voltage surge is applied. However, the stray capacitance component 72 and the stray inductance component 74 exist. For this reason, if the electronic component E1 is added to the input side of a semiconductor device that handles a high-speed signal as an input signal, it causes deterioration of the high-speed signal. In order to apply the electronic component E1 to a circuit that handles high-speed signals, it is preferable to reduce not only the stray capacitance component 72 but also the stray inductance component 74.

ただし、ＫｚＬｚ≧Ｌｅである。このように設計すると、電子部品Ｅ１に浮遊容量成分７２と浮遊インダクタンス成分７４が含まれていても、入力インピーダンスＺｉｎを特性インピーダンスＺｏに整合させることができる。 As can be seen from the equivalent circuit shown in FIG. 4, the floating inductance component 74 of the varistor 62 can be canceled by using the third inductance component 68 having a negative induction coefficient. However, since it appears to be the same as the state where the coupling is small, the coupling coefficient Kz and the induction coefficient Lz are left as they are, and the capacitance Cs of the capacitive component 60 is expressed by the following equation (4). Here, the induction coefficient of the floating inductance component 74 is Le.

However, KzLz ≧ Le. With this design, the input impedance Zin can be matched to the characteristic impedance Zo even if the electronic component E1 includes the stray capacitance component 72 and the stray inductance component 74.

  Next, a method for manufacturing the electronic component E1 according to the first embodiment will be described with reference to FIGS. FIG. 6 is a flowchart for explaining a process of manufacturing the electronic component according to the first embodiment. 7 to 12 are perspective views showing one process of the manufacturing process of the electronic component according to the first embodiment. In the flowchart shown in FIG. 6, step is abbreviated as S.

  First, in Step 1, a paste containing a ceramic material as a raw material for the insulator 10 and the varistor element body 20, a conductor paste for forming the first and second inner conductors 12 and 14, and the first and second varistor electrodes 22. , 24 is produced. Specifically, the paste for forming the insulating layer 10 can be obtained by adding a small amount of ZnO to a borosilicate glass powder, adding a binder or the like to the powder, and kneading. The paste for forming the varistor element body 20 is based on ZnO as the main component, and as an additive, at least one element selected from the group consisting of rare earths (for example, Pr) and Bi, Co, and optionally Al. , Cr, Ca, Si, K, and the like are added so as to have a desired content after firing, and a binder or the like is added thereto and kneaded. The metal element in this case can be added as an oxide, for example. A conductor paste containing Ag as a main component and an electrode paste containing Pd or a Pd—Ag alloy as a main component are prepared.

  Subsequently, in Step 2, the paste for forming the varistor element body 20 is applied on a plastic film or the like by a doctor blade method or the like and then dried to form varistor green sheets A1 to A4. When forming these varistor green sheets A1 to A4, the plastic film or the like may be peeled off from each varistor green sheet A1 to A4 immediately after applying and drying the paste. -A4 may be peeled off.

  Subsequently, in step 3, the electrode paste for forming the first and second varistor electrodes 22 and 24 is formed on the varistor green sheets A2 and A3 so that each sheet has a desired electrode pattern. Screen print. In step 4, the varistor green sheets A1 to A4 including the varistor green sheets A2 and A3 on which the electrode patterns corresponding to the first and second varistor electrodes 22 and 24 are formed are sequentially applied in the order shown in FIG. Laminate and apply pressure in the laminating direction and pressure-bond so that no gap is generated between the varistor green sheets A1 to A4.

  Subsequently, in Step 5, the varistor green sheets A1 to A4 that have been press-bonded are cut into chips, and then baked at a predetermined temperature (for example, about 1000 ° C. to 1400 ° C.) to generate the varistor element body 20 (FIG. 7). The varistor element body 20 has, for example, a length in the longitudinal direction after firing of about 1.4 mm, a width of about 1.0 mm, and a height of about 0.4 mm.

  Subsequently, in step 6, glass paste is applied so as to cover the surface of each varistor element body 20 cut in chip units (side surfaces on which the first to third terminal electrodes 30, 32, 34 and the external conductor 36 are not formed). Is screen-printed in a sheet form to form a glass green sheet B1 (see FIG. 8). Then, the conductor paste is screen-printed on the surface of the glass green sheet B1 so that one end is drawn to one short side of the glass green sheet B1 and the other end is drawn to one long side of the glass green sheet B1. Thus, a conductor pattern C1 to be the second inner conductor 14 is formed (see FIG. 9). Further, the glass paste is screen-printed in a sheet shape so as to cover the surfaces of the glass green sheet B1 and the conductor pattern C1, thereby forming the glass green sheet B2 (see FIG. 10). At this time, in order to ensure the connection between the conductor pattern C1 and the second terminal electrode 32 and the external conductor 36 formed in a later step, as shown in FIG. 10, each end of the conductor pattern C1 is exposed. Preferably, the glass green sheet B2 is formed. Then, the conductive paste is applied to the surfaces of the glass green sheet B2 and the conductor pattern C1 so that one end is drawn to one short side of the glass green sheet B2 and the other end is drawn to one long side of the glass green sheet B2. A conductor pattern C2 to be the first inner conductor 12 is formed by screen printing (see FIG. 11). Further, the glass paste is screen-printed in a sheet shape so as to cover the surfaces of the glass green sheet B2 and the conductor pattern C2, thereby forming the glass green sheet B3 (see FIG. 12). Also at this time, in order to ensure the connection between the conductor pattern C2 and the first terminal electrode 30 and the external conductor 36 formed in a later step, as shown in FIG. It is preferable to form the glass green sheet B2 so as to be exposed. In addition, each glass green sheet B1-B3 is each printed by the thickness of about 10 micrometers, for example.

  Subsequently, in Step 7, after the binder removal process, the glass green sheets B1 to B3 are fired together with the conductor patterns C1 and C2 at a predetermined temperature (for example, about 800 ° C. to 900 ° C.) to generate the insulator 10. The insulator 10 has, for example, a length in the longitudinal direction after firing of about 1.3 mm, a width of about 0.9 mm, and a height of about 0.1 mm. The glass green sheets B1 to B3 function as an insulating layer that exhibits insulating properties when fired.

  In step 8, the paste containing Ag as a main component is transferred so as to be connected to the end portions of the inner conductors 12, 14 and the varistor electrodes 22, 24, and then a predetermined temperature (for example, 800 ° C. to 900 ° C.). The first to third terminal electrodes 30, 32, 34 and the external conductor 36 are formed by baking at a temperature of about 0 ° C. and further by electroplating. For example, Cu and Ni and Sn, Ni and Sn, Ni and Au, Ni and Pd and Au, Ni and Pd and Ag, or Ni and Ag can be used for plating.

  By the way, when manufacturing an electronic component having an inductor and a varistor, conventionally, an inductor portion including the inductor and a varistor portion including the varistor are simultaneously fired. Here, the inductor portion preferably has a low dielectric constant in order to reduce the capacitance component due to the inductor itself. The varistor portion is preferably composed mainly of ZnO in order to obtain a varistor that exhibits excellent voltage nonlinearity. However, when materials having different physical properties are simultaneously fired in the inductor portion and the varistor portion, mutual diffusion occurs in the vicinity of the interface between the inductor portion and the varistor portion. Since the composition changes in a region where mutual diffusion occurs in this way, an inductor cannot be disposed in that region. Therefore, in the conventional electronic component, it is necessary to form a thicker inductor portion in consideration of mutual diffusion, and there is a problem that it is difficult to reduce the size of the electronic component. In addition, when the physical properties of the inductor part and the varistor part are different as described above, the shrinkage is different and the difference in volume change is large. Etc. would occur. On the other hand, when materials having physical properties approximate to the inductor portion and the varistor portion are used, there is a problem in that the capacitance component due to the inductor itself increases and good inductor characteristics cannot be obtained.

  Further, when an electronic component is manufactured by simultaneous firing as in the prior art, the material constituting the inductor is also fired at the sintering temperature (about 1000 ° C. to 1400 ° C.) when the varistor portion is generated. For this reason, a material having a higher melting point and higher resistance than the sintering temperature (for example, Pd) has to be used. Therefore, the conventional electronic component attenuates the signal, and is not suitable for high-speed transmission.

  However, in the first embodiment, the varistor green sheets A1 to A4 including the varistor green sheets A2 and A3 on which the electrode pastes corresponding to the first and second varistor electrodes 22 and 24 are formed are laminated and fired. Thus, the varistor element body 20 is generated. Then, the glass green sheet and the conductor pattern are alternately printed and laminated on the varistor element body 20, and then fired to generate the insulator 10. Therefore, since the insulator 10 and the varistor element body 20 are separately fired and generated, mutual diffusion hardly occurs in the vicinity of the interface between the insulator 10 and the varistor element body 20. As a result, there is almost no region in which the inductor cannot be arranged due to the change in the characteristics of the insulator 10 due to the mutual diffusion, and it is not necessary to print an extra glass green sheet in consideration of the mutual diffusion. In addition, the electronic component E1 can be downsized.

  In the first embodiment, since the insulator 10 and the varistor element body 20 are separately fired and produced, the electronic component E1 can be used even if the insulator 10 and the varistor element body 20 have different physical properties. Strain and stress are less likely to occur.

  In the first embodiment, the insulator 10 is formed by alternately printing and laminating glass green sheets and conductor patterns. Therefore, the conductor pattern is not crushed and disconnected, and the shape of the conductor pattern is kept printed. As a result, the first and second inner conductors 12 and 14 can be formed with high density, and the electronic component E1 can be further downsized.

  Further, in the first embodiment, the insulator 10 has the first and second inner conductors 12 and 14 that are coupled to each other with the polarity reversed. Therefore, it is possible to cancel the influence of the stray capacitance component 72 by using the third inductance component 68 of the first and second inner conductors 12 and 14 with respect to the stray capacitance component 72 of the varistor 62. Become. As a result, an input impedance with a flat frequency characteristic can be realized over a wide band.

  Further, in the first embodiment, the insulator 10 is made of glass, and the sintering temperature of the material constituting the insulator 10 is lower than the sintering temperature of the material constituting the varistor element body 20. Yes. Therefore, the first and second inner conductors 12 and 14 can be formed of Ag having a relatively low melting point of about 960 ° C. and low resistance, and transmission characteristics can be improved. Further, as the glass green sheets B1 to B3 are sintered, the glass green sheet B1 conforms to the varistor element body 20, so that the insulator 10 and the varistor element body 20 are sufficiently fixed.

(Second Embodiment)
Next, the configuration of the electronic component E2 according to the second embodiment will be described with reference to FIGS. FIG. 13 is a perspective view showing the inside of the electronic component according to the second embodiment. FIG. 14 is an exploded perspective view for explaining the configuration of the varistor element body included in the electronic component according to the second embodiment. The electronic component E2 according to the second embodiment includes a first inner conductor 12, a second inner conductor 14, a first varistor electrode 22, a second varistor electrode 24, a first terminal electrode 30, and a second terminal electrode 32. The numbers of the third terminal electrodes 34 and the external conductors 36 are different from those of the electronic component E1 according to the first embodiment.

  The electronic component E <b> 2 includes an insulator 10 and a varistor element body 20. Further, the electronic component E2 includes a plurality (two in the second embodiment) of the first terminal electrode 30, the second terminal electrode 32, the third terminal electrode 34, and the external conductor 36, respectively. The first terminal electrode 30, the second terminal electrode 32, and the third terminal electrode 34 are formed on the side surfaces of the insulator 10 and the varistor element body 20 so as to face each other. The outer conductors 36 are formed at the ends of the insulator 10 and the varistor element body 20 in the longitudinal direction.

  As shown in FIG. 13, the insulator 10 has a plurality of first inner conductors 12 and a plurality of second inner conductors 14 (two in the present embodiment) that are coupled to each other with the polarity reversed. The first inner conductors 12 and the second inner electrodes 14 have a predetermined interval inside the insulator 10 so as to be electrically insulated from each other.

  As shown in FIG. 14, the varistor element body 20 includes varistor green sheets A2 and A3 on which a plurality (two in the second embodiment) of first varistors 22 and second varistors 24 are formed. It is configured by laminating a plurality (four in the second embodiment) of varistor green sheets A1 to A4.

  A first varistor electrode 22 is formed on the surface of the varistor green sheet A2 so as to have a predetermined interval so as to be electrically insulated from each other. Each first varistor electrode 22 includes a first electrode portion 22a and a second electrode portion 22b. The first electrode portion 22a overlaps the first electrode portion 24a of the second varistor electrode 24 described later, as viewed from the stacking direction of the varistor green sheets A1 to A4. The first electrode portion 22a has a substantially rectangular shape. The second electrode portion 22b is drawn out from the first electrode portion 22a so as to be exposed on the side surface (side surface on which the external conductor 36 is formed) of the varistor element body 20, and functions as a lead conductor. Each first electrode portion 22a is electrically connected to the outer conductor 36 through the second electrode portion 22b. The second electrode portion 22b is formed integrally with the first electrode portion 22a.

  A second varistor electrode 24 is formed on the surface of the varistor green sheet A3. The second varistor electrode 24 includes a first electrode portion 24a and a second electrode portion 24b. The first electrode portion 24a overlaps the first electrode portion 22a of the first varistor electrode 22 when viewed from the stacking direction of the varistor green sheets A1 to A4. Each of the first electrode portions 24a has a substantially rectangular shape. The second electrode portions 24b are drawn out from the first electrode portions 24a so as to be exposed on both side surfaces of the varistor element body 20 (both side surfaces on which the third terminal electrodes 34 are formed). Function as. Each first electrode portion 24a is electrically connected to the third terminal electrode 34 through the second electrode portion 24b. The second electrode portion 24b is formed integrally with the first electrode portion 24a.

  In the varistor element 20, each first electrode portion 22a, each first electrode portion 24a, and each region in the varistor green sheet A2 where the first electrode portion 22a and the second electrode portion 24a overlap each other are 2 Each varistor will be configured.

  As described above, also in the second embodiment, similarly to the first embodiment, the occurrence of interdiffusion can be suppressed, and an array-shaped electronic component E2 that can be reduced in size compared to the conventional one. Can be realized.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments. For example, in the first and second embodiments, the first and second inner conductors 12 and 14 are provided, but only one of them may be provided. In the first and second embodiments, the conductor pattern is formed so that the first and second inner conductors 12 and 14 function as inductors. However, the first and second inner conductors 12 and 14 serve as resistors. A conductor pattern may be formed to function. Furthermore, the conductor pattern may be formed so that the first and second inner conductors 12 and 14 are a combination of an inductor and a resistor.

  In the first and second embodiments, the insulator 10 is made of glass. However, the present invention is not limited to this, and any material lower than the sintering temperature of the material constituting the varistor element body 20 may be used. In the first and second embodiments, the first and second inner conductors 12 and 14 are formed of Ag. However, the present invention is not limited to this, and an alloy mainly composed of Ag or a material that is sintered together with the insulating layer. Can be used.

  Further, when the insulator 10 contains ZnO, the characteristics of the insulator 10 and the varistor element body 20 are approximated, and mutual diffusion occurs extremely near the interface between the insulator 10 and the varistor element body 20. Since it becomes difficult, it is preferable.

It is a schematic perspective view for demonstrating the connection state of each internal conductor, each terminal electrode, and external conductor in the electronic component which concerns on 1st Embodiment. It is a disassembled perspective view for demonstrating the structure of the varistor element | base_body with which the electronic component which concerns on 1st Embodiment is provided. It is a figure for demonstrating the circuit structure of the electronic component which concerns on 1st Embodiment. It is a figure which shows the equivalent circuit of the circuit structure shown by FIG. It is a figure which shows the equivalent circuit of a varistor. It is a flowchart for demonstrating the process of manufacturing the electronic component which concerns on 1st Embodiment. It is a perspective view which shows 1 process of the manufacturing process of the multilayer inductor which concerns on 1st Embodiment. FIG. 8 is a perspective view showing a step subsequent to FIG. 7. FIG. 9 is a perspective view showing a step subsequent to FIG. 8. FIG. 10 is a perspective view showing a step subsequent to FIG. 9. FIG. 11 is a perspective view showing a step subsequent to FIG. 10. FIG. 12 is a perspective view showing a step subsequent to FIG. 11. It is a schematic perspective view for demonstrating the connection state of each internal conductor, each terminal electrode, and external conductor in the electronic component which concerns on 2nd Embodiment. It is a disassembled perspective view for demonstrating the structure of the varistor element | base_body with which the electronic component which concerns on 2nd Embodiment is provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Insulator, 12 ... 1st internal conductor, 14 ... 2nd internal conductor, 20 ... Varistor element | base_body,
DESCRIPTION OF SYMBOLS 22 ... 1st varistor electrode, 24 ... 2nd varistor electrode, 30 ... 1st terminal electrode, 32 ... 2nd terminal electrode, 34 ... 3rd terminal electrode, 36 ... External conductor, 62 ... Varistor, A1-A4 ... varistor green sheets, B1 to B3 ... glass green sheets, C1, C2 ... conductor patterns, E1, E2 ... electronic components.

Claims (9)

A varistor element body having a varistor including a varistor layer expressing voltage nonlinearity and a pair of varistor electrodes positioned so as to sandwich the varistor layer;
An insulator provided with an inductor, fixed to the varistor element body;
An electronic component, wherein a sintering temperature of a material constituting the insulator is lower than a sintering temperature of a material constituting the varistor layer. A first terminal electrode, a second terminal electrode, and a third terminal electrode formed on side surfaces of the insulator and the varistor element body, respectively.
The insulator has a first inner conductor and a second inner conductor that are coupled to each other in the opposite polarity and each function as the inductor;
One end of the first inner conductor is connected to the first terminal electrode, one end of the second inner conductor is connected to the second terminal electrode, and the other end of the first inner conductor and the first 2 is connected to the other end of the inner conductor,
One of the pair of varistor electrodes is connected to a connection point between the first inner conductor and the second inner conductor, and the other of the pair of varistor electrodes is connected to the third terminal electrode. The electronic component according to claim 1, wherein the electronic component is an electronic component.   The electronic component according to claim 1, wherein the insulator is made of a material having a dielectric constant lower than that of the material constituting the varistor layer.   The electronic component according to claim 3, wherein the insulator includes glass as a main component, and the inductor includes silver as a main component.   The electronic component according to claim 1, wherein the insulator and the varistor layer each contain ZnO. By arranging a pair of electrode patterns to be varistor electrodes so as to sandwich a varistor green sheet to be a varistor layer that expresses voltage nonlinearity, and laminating and firing the varistor green sheet and the electrode pattern together, Producing a varistor element body having varistors;
A step of alternately printing and laminating an insulator green layer and a conductor pattern to be an inductor on the varistor element body;
Firing the insulator green layer and the conductor pattern at a temperature lower than the sintering temperature of the material constituting the varistor green sheet to produce an insulator having the inductor. Manufacturing method of electronic components.   The method of manufacturing an electronic component according to claim 6, wherein the insulator green layer is made of a material having a dielectric constant lower than that of the material constituting the varistor green sheet.   The method of manufacturing an electronic component according to claim 7, wherein the insulator green layer includes a glass component as a main component, and the conductor pattern includes silver as a main component.   The method of manufacturing an electronic component according to any one of claims 6 to 8, wherein the insulator green layer and the varistor green sheet each contain ZnO.

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