JP2008251611A - Thin composite element and manufacturing process of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a thin and small-sized composite element that is resistive to ESD by forming a thermistor and a varistor in the form of a thin-film single chip. <P>SOLUTION: The thin composite element 10 is provided with: a thin-film varistor 12 formed on an insulated substrate 11; a pair of interdigitized electrodes 13, 14 provided in opposition with each other and formed of a conductive layer formed on the thin-film varistor; a thin-film thermistor 16 covering the thin-film varistor and electrodes 13, 14 to expose each substrate of these electrodes bridging over a pair of interdigitized electrodes; first and a second leadout electrodes 17, 18 formed on the insulated substrate on which the thin-film varistor is not formed, for electrical connection with an exposed base portion of one of the pair of interdigitized electrodes; and a protection film 19 covering all elements 12, 13, 14, 16 on the substrate, except for the pads 17c, 18c for connection of the lead wires of the electrodes 17, 18. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thin composite element having a thin film thermistor and a thin film varistor, and a method for manufacturing the same.

  Conventionally, in a negative thermistor, when an ESD (Electro Static Discharge) exceeding 15 kV is applied to a human body model (discharge from 100 pF through a series resistance of 1.5 kΩ), the resistance value fluctuates by several to several tens of percent. May occur, and the reliability is not always sufficient. In order to improve this point, there is provided a multilayer composite element in which a negative characteristic thermistor element made of semiconductor ceramic having negative characteristics and a varistor element made of semiconductor ceramics having varistor characteristics are laminated and integrated through an internal electrode. In addition, a negative characteristic thermistor device is disclosed in which an external electrode is disposed in a multilayer composite element so that a negative characteristic thermistor element and a varistor element are electrically connected in parallel (see, for example, Patent Document 1).

The laminated composite element of this negative characteristic thermistor device is a predetermined number of green sheets for forming a negative characteristic thermistor element obtained by forming a semiconductor ceramic material having negative characteristics into a sheet shape, and an internal electrode pattern is arranged on the predetermined one. A predetermined number of green sheets for forming a varistor element in which a semiconductor ceramic having varistor characteristics is formed into a sheet shape, and a predetermined green sheet having an internal electrode pattern disposed thereon are integrated. After the laminate is formed, the laminate is fired, and the negative temperature coefficient thermistor element and the varistor element are laminated and integrated through the internal electrodes. According to this negative characteristic thermistor device, it is possible to cope with the downsizing of the portable device without increasing the manufacturing cost, and it is strong against ESD, small in size, and high in reliability.
JP 2002-252103 (Claim 1, [0004], summary)

  Since the negative characteristic thermistor device shown in Patent Document 1 has a bulk structure in which a laminate of ceramic green sheets is integrally sintered, the thermistor element has a large heat capacity and a low thermal response. Although this device is downsized, it has a bulk structure, so the degree of downsizing is not sufficient.

  An object of the present invention is to provide a thin composite element that is strong against ESD, is thin, small, and has high-speed thermal response, and a method of manufacturing the same, by forming a thermistor and a varistor into a single chip by forming each thermistor and varistor into one chip. .

  As shown in FIGS. 1 and 2, the invention according to claim 1 of the present application is a pair of opposed thin film varistors 12 formed on an insulating substrate 11 and conductive layers formed on the thin film varistor 12. A comb-shaped electrode 13, 14 and a thin-film thermistor 16 covering the thin-film varistor 12 and the electrodes 13, 14 so as to straddle the pair of comb-shaped electrodes 13, 14 and expose the bases of the pair of comb-shaped electrodes; A first extraction electrode 17 formed on the insulating substrate 11 on which the thin film varistor 12 is not formed so as to be electrically connected to one exposed base of the pair of comb-shaped electrodes 13 and 14; A second extraction electrode 18 formed on the insulating substrate 11 where the thin film varistor 12 is not formed so as to be electrically connected to the other exposed base of the comb electrodes 13 and 14; 2 drawing electricity Pad portion 17c for connecting the lead wire of 17, a thin composite element 10 having a protective film 19 which covers all the elements 12,13,14,16 in the substrate except for 18c.

  As shown in FIG. 4, the invention according to claim 5 of the present application is a pair of opposing comb electrodes comprising a thin film thermistor 22 formed on an insulating substrate 21 and a conductive layer formed on the thin film thermistor 22. 23, 24, and the thin film varistor 26 covering the thin film thermistor 22 and the electrodes 23, 24 so as to straddle the pair of comb electrodes 23, 24 and expose the bases of the pair of comb electrodes. A third lead electrode 27 formed on the insulating substrate 21 where the thin film thermistor 22 is not formed so as to be electrically connected to one exposed base of the comb electrodes 23, 24, and a pair of comb electrodes A fourth extraction electrode 28 formed on the insulating substrate 21 on which the thin film thermistor 22 is not formed so as to be electrically connected to the other exposed bases 23 and 24, and the third and fourth extraction powers. Pad portion 27c for connecting the lead wire of 27, a thin composite element 20 having a protective film 29 which covers all the elements 22,23,24,26 in the substrate except for 28c.

  In the invention according to claim 9 of the present application, as shown in FIGS. 1 and 2, a process of forming a thin film varistor 12 with a predetermined pattern on an insulating substrate 11 and a conductive layer on the thin film varistor 12 are opposed to each other. The step of forming the pair of comb-shaped electrodes 13 and 14 and the thin film varistor 12 and the electrodes 13 and 14 so as to straddle the pair of comb-shaped electrodes 13 and 14 and expose the bases of the pair of comb-shaped electrodes. The step of covering with the thin film thermistor 16 and the first extraction electrode on the insulating substrate 11 on which the thin film varistor 12 is not formed so as to be electrically connected to one exposed base of the pair of comb electrodes 13 and 14 17 and a second extraction electrode 18 on the insulating substrate 11 where the thin film varistor 12 is not formed so as to be electrically connected to the other exposed base of the pair of comb electrodes 13 and 14. The protective film 19 includes all the elements 12, 13, 14, and 16 on the substrate except the pad portions 17c and 18c for connecting the lead lines in the first and second lead electrodes 17 and 18 and the process of forming the lead wires. And manufacturing the thin composite element 10.

  As shown in FIG. 4, the invention according to claim 13 of the present invention is a process of forming a thin film thermistor 22 in a predetermined pattern on an insulating substrate 21, and a pair of opposing combs made of conductive layers on the thin film thermistor 22. The thin film thermistor 22 and the electrodes 23 and 24 are formed into a thin film varistor 26 so as to straddle the pair of comb electrodes 23 and 24 and to expose the bases of the pair of comb electrodes. And a third extraction electrode 27 is formed on the insulating substrate 21 on which the thin film thermistor 22 is not formed so as to be electrically connected to one exposed base portion of the pair of comb-shaped electrodes 23 and 24. And a fourth extraction electrode 28 on the insulating substrate 21 where the thin film thermistor 22 is not formed so as to be electrically connected to the other exposed base of the pair of comb-shaped electrodes 23, 24. A protective film 29 is formed on all the elements 22, 23, 24, 26 on the substrate except for the step of forming and the pad portions 27c, 28c for connecting the lead lines in the third and fourth lead electrodes 27, 28. And manufacturing the thin composite element 20.

  The invention according to claim 3 or 7 of the present application is the invention according to claim 1 or 5, wherein the insulating substrates 11 and 21 are silicon substrates 11 a and 21 a having insulating films 11 b and 21 b on the upper surface of the substrate. Alternatively, the thin composite elements 10 and 20 are formed in which the cavities or recesses 11c and 21c of the silicon substrates 11a and 21a are formed with the insulating films 11b and 21b left below the thin film thermistor 22.

  The invention according to claim 11 or 15 of the present application is the invention according to claim 9 or 13, wherein the insulating substrates 11 and 21 are silicon substrates 11a and 21a having insulating films 11b and 21b on the upper surface of the substrate, respectively, and a thin film varistor. 12 or the thin film thermistor 22 is a method for manufacturing the thin composite elements 10 and 20 in which the cavities or recesses 11c and 21c of the silicon substrates 11a and 21a are formed by etching using the insulating films 11b and 21b as etching stoppers.

  In the thin composite element according to claim 1 or 5, the thermistor and the varistor are each a thin film, and the thin film thermistor and the thin film varistor commonly use a pair of comb-shaped electrodes. In addition, since the thin film thermistor and the thin film varistor share the comb-shaped electrode and are connected in parallel, the thin composite element is resistant to ESD and has high speed thermal response. Further, since the comb electrode is sandwiched between the thin film thermistor and the thin film varistor, the bonding property between the electrodes of both thin films is improved. Further, since all the elements on the substrate except for the pad portion for connecting the leader line are covered with the protective film, the thermistor does not directly touch the external atmosphere. Thereby, it is hard to be influenced by the humidity of the atmosphere in which the composite element is used, and is excellent in moisture resistance.

  According to the method for manufacturing a thin composite element according to claim 9 or 13 of the present application, it is possible to manufacture a thin composite element having the above features.

  In addition, the thin composite element according to claim 3 or 7 of the present application forms a cavity or recess in the silicon substrate leaving an insulating film below the thin film varistor or thin film thermistor. Is even higher.

  Furthermore, in the method for manufacturing a thin composite element according to claim 11 or 15 of the present application, a cavity or a recess can be easily formed in the silicon substrate by etching using the insulating film on the silicon substrate as an etching stopper.

  The best mode of the present invention will be described below.

<First Embodiment>
As shown in FIG. 1, the thin composite element 10 according to the first embodiment of the present invention includes a thin film varistor 12, a pair of comb electrodes 13, 14, a thin film thermistor 16, a first extraction electrode 17, and a first electrode on an insulating substrate 11. Two extraction electrodes 18 and a protective film 19 are provided. Examples of the insulating substrate 11 include those having a silicon substrate 11a and an insulating film 11b formed on the upper surface of the substrate. The silicon substrate 11 with an insulating film is preferable because a cavity or a recess (see FIGS. 5 and 6) described later can be easily formed by etching under the insulating film. Examples of other insulating substrates include glass substrates and ceramic substrates. The substrate is determined from a thickness range of 0.1 to 0.5 mm. The silicon substrate with an insulating film is formed so as to have a SiO ₂ film having a thickness of 100 to 1000 nm on the substrate surface by thermally oxidizing the silicon substrate and by chemical vapor deposition on the silicon substrate surface.

  A thin film varistor 12 formed on an insulating substrate 11 is a complex metal oxide film containing ZnO as a main component and containing Bi or Pr, and further adding Co, Sb, Mn, Ni, Cr, Ti, Al, or the like. It has a wurtzite crystal structure. The additive content of Bi, Pr, Co, Sb, Mn, Ni, Cr, Ti, Al, etc. with respect to ZnO is determined according to desired varistor characteristics. The thin film varistor 12 is formed by sputtering at the center of the upper surface of the insulating substrate 11. The thickness of the thin film varistor 12 is determined from a range of 100 to 1000 nm according to desired characteristics. On the thin film varistor 12, a pair of comb-shaped electrodes 13 and 14 which are smaller in area than the thin film varistor and are made of conductive layers such as Au and Pt are formed.

A thin film thermistor 16 is formed on the thin film varistor 12 and the pair of comb electrodes 13 and 14. The thin film thermistor 16 has a smaller area than the thin film varistor 12 and covers the thin film varistor 12 and the electrodes 13 and 14 so as to straddle the pair of comb electrodes 13 and 14 and to expose the bases of the pair of comb electrodes. . The thin film thermistor is at least one selected from the group consisting of Mn—Co based composite metal oxide (Mn _x Co _1-x ) ₃ O ₄ or Mn—Co based composite metal oxide comprising Ni, Fe, Cu and Al. A composite metal oxide containing a seed (for example, a composite metal oxide made of (Mn _x Co _y Ni _1-xy ) ₃ O _4. This composite metal oxide has a spinel crystal structure, and has a thickness direction. It has an extended columnar crystal structure, and the composition ratio of Mn, Co, Ni, Fe, Cu, Al, etc. is determined according to the desired characteristics of the thermistor. Depending on the range of 100 to 1000 nm.

One end of each of the first and second lead electrodes 17 and 18 is electrically connected to the bases of the comb electrodes 13 and 14 and the thin film varistor 12 which are not covered with the thin film thermistor. The other ends of the extraction electrodes 17 and 18 are formed on the insulating substrate 11 on which the thin film varistor 12 is not formed. The first and second lead electrodes 17 and 18 are formed of Cr, Ti, and other bonding layers 17a and 18a formed on an insulating substrate, and Au formed on the bonding layer in the same shape and size as the bonding layer. , Pt or the like and the conductive layers 17b and 18b. The bonding layer has a function of increasing the degree of bonding of the conductive layer to the comb electrode or the like as a base electrode of the conductive layer. Further, all elements on the substrate except the pad portions 17c and 18c for connecting lead wires (not shown) such as lead wires in the first and second lead electrodes 17 and 18, that is, the thin film varistor 12, The comb electrodes 13 and 14 and the thin film thermistor 16 are covered with a protective film 19 such as silicon dioxide (SiO ₂ ) or silicon nitride (Si ₃ N ₄ ). As a result, a thin composite element 10 having a total thickness of 0.1 to 0.5 mm and a length of 0.4 to 1 mm and a width of 0.2 to 0.5 mm is obtained.

<Second Embodiment>
As shown in FIG. 4, the thin composite element 20 of the second embodiment of the present invention includes a thin film thermistor 22, a pair of comb-shaped electrodes 23 and 24, a thin film varistor 26, a third extraction electrode 27, and a first electrode on an insulating substrate 21. Four extraction electrodes 28 and a protective film 29 are provided. Examples of the insulating substrate 21 include those having a silicon substrate 21a and an insulating film 21b formed on the upper surface of the substrate. The silicon substrate 21 with an insulating film is preferable because a cavity or a recess (see FIGS. 5 and 6) described later can be easily formed by etching under the insulating film. The thickness and type of the insulating substrate and the method for manufacturing the silicon substrate with the insulating film are the same as those in the first embodiment.

  The composition of the thin film thermistor 22 formed on the insulating substrate 21 is the same as the composition of the thin film thermistor 16 of the first embodiment, and the shape, size, and arrangement of the thin film thermistor 22 are the same as those of the thin film of the first embodiment. The shape, size, and arrangement of the varistor 12 are the same. Similarly, the composition, shape, size and arrangement of the pair of comb electrodes 23 and 24 are the same as the composition, shape, size and arrangement of the pair of comb electrodes 13 and 14. The composition of the thin film varistor 26 is the same as that of the thin film varistor 12 of the first embodiment, and the shape, size, and arrangement of the thin film varistor 26 are the same as those of the thin film thermistor 16 of the first embodiment. Same as placement. The composition, shape, size, and arrangement of the third and fourth extraction electrodes 27, 28 are the same as the shape, size, and arrangement of the first and second extraction electrodes 17, 18 of the first embodiment. Furthermore, the composition, shape, size, and arrangement of the protective film 29 are the same as the shape, size, and arrangement of the protective film 19 of the first embodiment. As a result, a thin composite element 20 having a total thickness of 0.1 to 0.5 mm and a length of 0.4 to 1 mm and a width of 0.2 to 0.5 mm is obtained.

<Third Embodiment>
As shown in FIG. 5, the thin composite element 10 of the third embodiment of the present invention has a recess 11c in the silicon substrate 11a, leaving an insulating film 11b below the thin film varistor 12 of the thin composite element 10 of the first embodiment. Is formed. Although not shown, a cavity may be used instead of the recess 11c.

<Fourth embodiment>
As shown in FIG. 6, the thin composite element 20 of the fourth embodiment of the present invention has a recess 21c of the silicon substrate 21a, leaving an insulating film 21b below the thin film thermistor 22 of the thin composite element 20 of the second embodiment. Is formed. Although not shown, a cavity may be used instead of the recess 21c.

  Next, examples of the present invention will be described.

<Example 1>
A method for manufacturing the thin composite element shown in FIGS. 1 and 2 will be described. First, as shown in FIG. 3A, an SiO ₂ layer 11b having a layer thickness of 500 nm is formed on a silicon substrate 11a having a thickness of 0.25 mm by a thermal oxidation method. ZnO on the entire upper surface of the SiO ₂ layer _{11b: 98.6mol%, Bi 2 O} 3: 0.2mol%, Sb 2 O 5: 0.1mol%, CoO: 0.5mol%, MnO 2: 0.2mol% A thin film containing Cr ₂ O ₃ : 0.2 mol% and NiO: 0.2 mol% is formed by a sputtering method so as to have a film thickness of 500 nm. A photosensitive resin is formed on the entire surface of the thin film, exposed using a predetermined photomask, developed, and patterned. Using the photosensitive resin as a mask, the thin film is patterned into a desired shape by a lift-off method. By heat-treating this substrate at 900 ° C. for 2 hours, as shown in FIG. 3B, a highly reliable thin film varistor 12 having a stable varistor voltage is obtained.

Next, an Au thin film for forming electrodes on the entire surface of the thin film varistor 12 and the SiO ₂ layer 11b is formed by sputtering so that the film thickness becomes 200 nm. A photosensitive resin is formed on the entire surface of the Au thin film, exposed using a predetermined photomask, developed, and patterned. Using the photosensitive resin as a mask, the Au thin film is patterned by wet etching using a potassium iodide iodide solution. As shown in FIG. 3C, a desired pair of comb-shaped electrodes 13 and 14 made of a conductive film are formed. obtain.

Next, a thin film having a spinel structure of (Mn _0.4 Co _0.6 ) ₃ O ₄ is formed on the entire upper surface of the substrate on which the comb-shaped electrode is formed by sputtering. A photosensitive resin is formed on the entire surface of the thin film, exposed using a predetermined photomask, developed, and patterned. Using the photosensitive resin as a mask, the thin film is patterned into a desired shape by wet etching using a diluted hydrochloric acid solution. The substrate is heat-treated at 600 ° C. for 1 hour to obtain a thin film thermistor 16 having a high resistance value and high B constant reliability, as shown in FIG.

Next, a Cr thin film for forming a base electrode serving as a bonding layer is formed on the entire surface of the thin film thermistor 16 and the SiO ₂ layer 11b by sputtering so that the film thickness becomes 100 nm. Subsequently, an Au thin film serving as a conductive layer is formed on the entire surface of the Cr thin film by a sputtering method so as to have a film thickness of 200 nm. A photosensitive resin is formed on the entire surface of the Au thin film, exposed using a predetermined photomask, developed, and patterned. Using the photosensitive resin as a mask, the Au thin film is patterned by wet etching using a potassium iodide iodide solution to obtain a conductive layer having a desired shape. Subsequently, by wet etching using a cerium ammonium nitrate solution, a Cr thin film serving as a base electrode is patterned into the same structure as the Au thin film, and a pair of comb-shaped elements is formed on the thin film varistor as shown in FIG. Lead electrodes 17 and 18 electrically connected to the bases of the electrodes 13 and 14 are obtained.

Further, a SiO ₂ thin film is formed on the entire surface of the substrate by sputtering so that the film thickness becomes 600 nm. A photosensitive resin is formed on the entire surface of the SiO ₂ thin film, exposed using a predetermined photomask, developed, and patterned. Using the photosensitive resin as a mask, the SiO ₂ thin film is patterned by wet etching using hydrofluoric acid, and as shown in FIG. 3 (f), only the pad portions 17c and 18c for connecting lead wires such as lead wires are exposed. Let As a result, a thin composite element 10 having a total thickness of 0.25 mm and a length of 1.0 mm and a width of 0.5 mm is obtained.

  The manufacturing method of a single composite element has been described above. When a composite element is mass-produced, a number of thin film thermistors with varistor functions are formed on a single silicon substrate, and the substrate is cut to have individual varistor functions. A thin composite element of a thin film thermistor is obtained.

<Example 2>
A method of manufacturing the thin composite element shown in FIG. 5 will be described. After turning over the composite element shown in FIG. 3F, a rectangular window 31 is formed by removing the SiO ₂ layer 11d at the center of the substrate as shown in FIG. 7A. The silicon substrate 11a has an SiO ₂ layer 11b formed on the upper surface and an SiO ₂ layer 11d formed on the lower surface. The window 31 is formed by masking the SiO ₂ layer 11d other than the window portion with a photosensitive resin and patterning the SiO ₂ layer 11d by wet etching using hydrofluoric acid. Subsequently, using the photosensitive resin as a mask, a part of the silicon substrate 11a corresponding to the lower part (upper part in FIG. 7) of the thin film varistor is etched by wet etching using a tetramethylammonium hydroxide aqueous solution (TMAH). A thin composite element of a thin film thermistor with a varistor function having a membrane structure as shown in 7 (b) is obtained.

It is the sectional view on the AA line of FIG.3 (f) of the thin composite element of 1st Embodiment of this invention. It is a disassembled perspective view of the thin composite element of 1st Embodiment of this invention. It is a perspective view which shows the manufacturing process of the thin composite element of 1st Embodiment of this invention. It is sectional drawing of the thin composite element corresponding to FIG. 1 of 2nd Embodiment of this invention. It is sectional drawing of the thin composite element corresponding to FIG. 1 of 3rd Embodiment of this invention. It is sectional drawing of the thin composite element corresponding to FIG. 1 of 4th Embodiment of this invention. It is a perspective view which shows the manufacturing process of the thin composite element of 3rd Embodiment of this invention.

Explanation of symbols

10: Thin composite element 11: Insulating substrate 12: Thin film varistor 13, 14: Pair of comb electrodes 16: Thin film thermistor 17: First extraction electrode 17a: Bonding layer 17b: Conductive layer 17c: Pad part 18: Second extraction electrode 18a: bonding layer 18b: conductive layer 18c: pad portion 19: protective film 20: thin composite element 21: insulating substrate 22: thin film thermistor 23, 24: pair of comb electrodes 26: thin film varistor 27: third extraction electrode 27a: Bonding layer 27b: Conductive layer 27c: Pad portion 28: Fourth extraction electrode 28a: Bonding layer 28b: Conductive layer 28c: Pad portion 29: Protective film

Claims (16)

A thin film varistor formed on an insulating substrate;
A pair of opposing comb electrodes made of a conductive layer formed on the thin film varistor;
A thin film thermistor that covers the thin film varistor and the electrode so that the bases of the pair of comb electrodes are exposed across the pair of comb electrodes;
A first extraction electrode formed on the insulating substrate on which the thin film varistor is not formed so as to be electrically connected to one exposed base of the pair of comb electrodes;
A second extraction electrode formed on the insulating substrate on which the thin film varistor is not formed so as to be electrically connected to the other exposed base of the pair of comb electrodes;
A thin composite element comprising: a protective film covering all elements on the substrate excluding a pad portion for connecting a lead line in the first and second lead electrodes.   2. The thin composite element according to claim 1, wherein the insulating substrate is a ceramic substrate, a glass substrate, or a silicon substrate having an insulating film on the upper surface of the substrate.   3. The thin composite element according to claim 1, wherein the insulating substrate is a silicon substrate having an insulating film on the upper surface of the substrate, and the cavity or recess of the silicon substrate is formed leaving the insulating film below the thin film varistor.   The first and second lead electrodes are constituted by a bonding layer formed on an insulating substrate and a conductive layer formed on the bonding layer in the same shape and size as the bonding layer. The thin composite element according to any one of the above. A thin film thermistor formed on an insulating substrate;
A pair of opposing comb electrodes made of a conductive layer formed on the thin film thermistor;
A thin film varistor that covers the thin film thermistor and the electrode so as to straddle the pair of comb electrodes and expose each base of the pair of comb electrodes;
A third extraction electrode formed on the insulating substrate on which the thin film thermistor is not formed so as to be electrically connected to one exposed base of the pair of comb electrodes;
A fourth extraction electrode formed on the insulating substrate on which the thin film thermistor is not formed so as to be electrically connected to the other exposed base of the pair of comb electrodes;
A thin composite element comprising: a protective film covering all elements on the substrate except for a pad portion for connecting a lead line in the third and fourth lead electrodes.   6. The thin composite element according to claim 5, wherein the insulating substrate is a ceramic substrate, a glass substrate, or a silicon substrate having an insulating film on the upper surface of the substrate.   The thin composite element according to claim 5 or 6, wherein the insulating substrate is a silicon substrate having an insulating film on the upper surface of the substrate, and the cavity or recess of the silicon substrate is formed leaving the insulating film below the thin film thermistor.   The third and fourth extraction electrodes are constituted by a bonding layer formed on an insulating substrate and a conductive layer formed on the bonding layer in the same shape and size as the bonding layer. The thin composite element according to any one of the above. Forming a thin film varistor with a predetermined pattern on an insulating substrate;
Forming a pair of opposing comb electrodes made of a conductive layer on the thin film varistor;
Covering the thin film varistor and the electrode with a thin film thermistor so as to straddle the pair of comb electrodes and expose each base of the pair of comb electrodes;
Forming a first extraction electrode on the insulating substrate on which the thin film varistor is not formed so as to be electrically connected to one exposed base of the pair of comb electrodes;
Forming a second extraction electrode on the insulating substrate on which the thin film varistor is not formed so as to be electrically connected to the other exposed base of the pair of comb electrodes;
A method of manufacturing a thin composite element, comprising: covering all elements on the substrate except for a pad portion for connecting lead lines in the first and second lead electrodes with a protective film.   The method for manufacturing a thin composite element according to claim 9, wherein the insulating substrate is a ceramic substrate, a glass substrate, or a silicon substrate having an insulating film on an upper surface of the substrate.   The thin composite element according to claim 9 or 10, wherein the insulating substrate is a silicon substrate having an insulating film on an upper surface of the substrate, and a cavity or a recess of the silicon substrate is formed by etching using the insulating film as an etching stopper below the thin film varistor. Manufacturing method.   The first and second extraction electrodes are formed by forming a bonding layer on an insulating substrate and then forming a conductive layer on the bonding layer in the same shape and size as the bonding layer. 11. A method for manufacturing a thin composite element according to any one of 11 above. Forming a thin film thermistor in a predetermined pattern on an insulating substrate;
Forming a pair of opposing comb electrodes made of a conductive layer on the thin film thermistor;
Covering the thin film thermistor and the electrode with a thin film varistor so as to straddle the pair of comb electrodes and expose each base of the pair of comb electrodes;
Forming a third extraction electrode on the insulating substrate on which the thin film thermistor is not formed so as to be electrically connected to one exposed base of the pair of comb electrodes;
Forming a fourth extraction electrode on the insulating substrate on which the thin film thermistor is not formed so as to be electrically connected to the other exposed base of the pair of comb electrodes;
A method of manufacturing a thin composite element including a step of covering all elements on the substrate except a pad portion for connecting lead lines in the third and fourth lead electrodes with a protective film.   The method for producing a thin composite element according to claim 13, wherein the insulating substrate is a ceramic substrate, a glass substrate, or a silicon substrate having an insulating film on an upper surface of the substrate.   15. The thin composite element according to claim 13, wherein the insulating substrate is a silicon substrate having an insulating film on the upper surface of the substrate, and a cavity or a recess of the silicon substrate is formed by etching using the insulating film as an etching stopper below the thin film thermistor. Manufacturing method.   The third and fourth extraction electrodes are formed by forming a bonding layer on the insulating substrate and then forming a conductive layer on the bonding layer in the same shape and size as the bonding layer. 15. A method for producing a thin composite element according to any one of 15 items.

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