JP4677952B2 - Thin film capacitor - Google Patents

Description

  The present invention relates to a thin film capacitor used in an electronic circuit or the like.

In an electronic circuit or the like, a polyimide insulating layer is formed on a metal frame, and a thin film capacitor is formed by laminating a lower electrode film, a dielectric film, and an upper electrode film in this order on the polyimide insulating layer. It has been proposed. And, for the wrinkle resistance in the dielectric film of the thin film capacitor, it has been proposed to set the linear expansion coefficient of the metal frame to be about 10 to 40 ppm / ° C. smaller than the linear expansion coefficient of the dielectric film (patent). Reference 1).
Japanese Patent Laid-Open No. 10-150274 (paragraph [0012])

  By the way, in order to efficiently mass-produce thin film capacitors, it is necessary to form them by a roll-to-roll method. That is, a polyimide insulating layer, a lower electrode film, a dielectric film, and an upper portion are continuously formed on a metal substrate while the metal substrate is drawn out from a roll body formed by winding a belt-like metal substrate in a roll shape. The electrode films are laminated in this order. Thereby, a thin film capacitor is continuously formed. Then, the thin film capacitor forming portion is cut by punching or the like to obtain individual thin film capacitor pieces, and the remaining unnecessary portions are wound into a roll.

  However, the strip-shaped metal substrate has a larger dimensional change due to a temperature change during the thin film capacitor forming process than a small piece metal substrate used in the batch method. Further, in the roll-to-roll method, since the thickness of the band-shaped metal substrate has to be reduced (for example, 100 μm or less), warpage is likely to occur during the formation of the thin film capacitor. For this reason, when continuously forming a thin film capacitor using a strip-like long metal substrate, there is a problem that wrinkles and cracks are likely to occur in the lower electrode film and the dielectric film thin film. When such wrinkles and cracks occur, there arises a problem that electrical characteristics as a capacitor are not sufficiently exhibited.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a thin film capacitor in which wrinkles and cracks are unlikely to occur even when the thin metal capacitor is formed using a long metal substrate.

  In order to achieve the above object, the thin film capacitor of the present invention is a thin film in which a lower electrode film, a dielectric film, and an upper electrode film are laminated in this order on a polyimide insulating layer formed on a long metal substrate. The capacitor, wherein the lower electrode film is composed of a plurality of laminated metal thin films or a single layer of metal thin film, and the linear expansion coefficient of the thickest metal thin film among the plurality of metal thin films constituting the lower electrode film Alternatively, the difference between the linear expansion coefficient of the single metal thin film and the linear expansion coefficient of the long metal substrate is 3 ppm / ° C. or less.

  In order to obtain a thin film capacitor in which wrinkles and cracks are less likely to occur even when using a long metal substrate, the present inventors have focused on the linear expansion coefficient and conducted extensive research. As a result of the research, when the lower electrode film is composed of a plurality of metal thin films, the coefficient of linear expansion of the entire lower electrode film is the thickest metal thin film among the plurality of metal thin films constituting the lower electrode film. If the difference between the coefficient of linear expansion of the thickest metal thin film and the coefficient of linear expansion of the long metal substrate is within 3 ppm / ° C., the thin film capacitor is formed using the long metal substrate. It was found that wrinkles and cracks are less likely to occur even when fabricated. Further, when the lower electrode film is made of one layer of metal thin film, the linear expansion coefficient of the entire lower electrode film is the linear expansion coefficient of the one layer of metal thin film, and the linear expansion coefficient of the one layer of metal thin film. And when the difference between the linear expansion coefficient of the long metal substrate is 3 ppm / ° C. or less, even if a thin film capacitor is produced using the long metal substrate, it is found that wrinkles and cracks are less likely to occur. Reached.

  The reason why wrinkles and cracks are less likely to occur in such a thin film capacitor is not clear, but if the difference in coefficient of linear expansion is set as described above, the lower electrode film and length due to temperature changes during the thin film capacitor formation process It is presumed that the polyimide insulating layer between them can be deformed following the dimensional change of the scale metal substrate, and the stress applied to the lower electrode film is relieved.

  In the present invention, the “long metal substrate” means a band-shaped metal substrate having a ratio of the length in the longitudinal direction to the length in the width direction (longitudinal direction / width direction) of 20 or more.

  In the thin film capacitor of the present invention, as described above, the difference between the linear expansion coefficient of the specific metal thin film constituting the lower electrode film and the linear expansion coefficient of the long metal substrate is set within 3 ppm / ° C. Even when a long metal substrate is used, the polyimide insulating layer between the long metal substrate and the lower electrode film relieves stress applied to the lower electrode film, and wrinkles and cracks are less likely to occur.

  In particular, when the difference between the linear expansion coefficient of the polyimide insulating layer and the linear expansion coefficient of the long metal substrate is within 10 ppm / ° C., wrinkles and cracks are less likely to occur.

  Further, when the difference between the linear expansion coefficient of the polyimide insulating layer and the specific metal thin film constituting the lower electrode film is within 10 ppm / ° C., wrinkles and cracks are less likely to occur.

  Furthermore, when the long metal substrate is an alloy of iron and nickel, since the linear expansion coefficient of the long metal substrate is small, the dimensional change of the long metal substrate due to the temperature change during the thin film capacitor forming process is small. Thus, wrinkles and cracks are less likely to occur.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to this.

  FIG. 1 shows an embodiment of the thin film capacitor of the present invention. The structure of the thin film capacitor includes a long metal substrate 1, a polyimide insulating layer 2 formed on the long metal substrate 1, a lower electrode film 3 laminated on a part of the polyimide insulating layer 2, The dielectric film 4 is laminated on a part of the lower electrode film 3 (left side in FIG. 1), and the upper electrode film 5 is laminated on the dielectric film 4. The lower electrode film 3 is formed by laminating a plurality of metal thin films (not shown). Among the metal thin films, the linear expansion coefficient of the thickest metal thin film and the long metal substrate 1 are formed. The difference from the linear expansion coefficient is within 3 ppm / ° C. In FIG. 1, reference numerals 6 and 7 are the other parts of the lower electrode film 3 (right side in FIG. 1) and external electrodes connected to the upper electrode film 5, respectively, and reference numeral 8 is an insulating layer.

  More specifically, the linear expansion coefficient of the long metal substrate 1 is preferably set in the range of 1 to 15 ppm / ° C, more preferably in the range of 1 to 8 ppm / ° C. Examples of such a metal material for the long metal substrate 1 include iron and nickel alloys, ferritic stainless steel, titanium, and titanium alloys. Among these, from the viewpoint of a low linear expansion coefficient, an alloy of iron and nickel is preferable. For example, 42 alloy (linear expansion coefficient 4.5 ppm / ° C.), 36 alloy (linear expansion coefficient 1.5 ppm / ° C.), Invar type alloy (Linear expansion coefficient 1.5 ppm / ° C.), Enliver type alloy (linear expansion coefficient 1.5 ppm / ° C.) and the like. Moreover, it is preferable to set the thickness of the elongate metal substrate 1 in the range of 10-100 micrometers, More preferably, it exists in the range of 10-50 micrometers.

  The linear expansion coefficient of the polyimide insulating layer 2 is preferably set in the range of −2 to 18 ppm / ° C., more preferably in the range of 3 to 9 ppm / ° C. This linear expansion coefficient can be set by adjusting the types of the following components constituting the polyimide insulating layer 2 and the blending ratio thereof. The linear expansion coefficient is at least a difference between the linear expansion coefficient of the long metal substrate 1 and a difference between the linear expansion coefficient of the thickest metal thin film among the plurality of metal thin films constituting the lower electrode film 3. One of them is preferably within 10 ppm / ° C. from the viewpoint of making the thin film capacitor less likely to be wrinkled or cracked. Moreover, it is preferable to set the thickness of the polyimide insulating layer 2 in the range of 5-50 micrometers, More preferably, it exists in the range of 10-30 micrometers. The polyimide insulating layer 2 can be formed, for example, by applying a polyamic acid solution on the long metal substrate 1 and drying it, followed by imidization by heating.

  The polyamic acid solution can be obtained by reacting acid dianhydride and diamine in a substantially equimolar ratio in an appropriate organic solvent. Examples of the organic solvent include N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylpyrrolidinone and the like.

  Examples of the acid dianhydride include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, and 3,3 ′. , 4,4'-benzophenone tetracarboxylic dianhydride, 2,2 ', 3,3'-benzophenone tetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride (ODPA), 2,2- Bis (2,3-dicarboxyphenyl) hexafluoropropane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA), bis (2,3-dicarboxyphenyl) ) Methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis (2,3-dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxypheny) ) Sulfone dianhydride, pyromellitic dianhydride, ethylene glycol bis trimellitic dianhydride and the like. These may be used alone or in combination of two or more.

  Examples of the diamine include 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether (34DDE), 3,3′-diaminodiphenyl ether, m-phenylenediamine, p-phenylenediamine, and 4,4′-diamino. Diphenylpropane, 3,3'-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4 ' -Diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m-toluylenediamine, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3- Bis (3-aminophenoxy) ben (APB), 1,3-bis (4-aminophenoxy) -2,2-dimethylpropane, hexamethylenediamine, 1,8-diaminooctane, 1,12-diaminododecane, 4,4'-diaminobenzophenone, etc. Can be given. These may be used alone or in combination of two or more.

  The lower electrode film 3 is usually composed of one thick metal thin film (thickest metal thin film) and one or more thin metal thin films formed on at least one side (one side or both sides) thereof. From the viewpoint of improving the adhesion between the polyimide insulating layer 2 and the dielectric film 4, it is preferable that one or more thin metal thin films are formed on both surfaces of the thickest metal thin film. That is, the number of metal thin films constituting the lower electrode film 3 is preferably in the range of 2 to 6 layers, more preferably in the range of 2 to 4 layers. The thickness of the thickest metal thin film is preferably set in the range of 0.4 to 1.2 μm, more preferably in the range of 0.6 to 1.0 μm. Is preferably set in the range of 2 to 50% of the thickness of the thickest metal thin film, more preferably in the range of 5 to 35%. And it is preferable to set the thickness of the whole lower electrode film 3 in the range of 0.4-1.5 micrometers, More preferably, it exists in the range of 0.8-1.2 micrometers.

  Further, the linear expansion coefficient of the entire lower electrode film 3 depends on the linear expansion coefficient of the thickest metal thin film among the plurality of metal thin films constituting the lower electrode film 3. Therefore, in this embodiment, the difference between the linear expansion coefficient of the thickest metal thin film and the linear expansion coefficient of the metal substrate is set within 3 ppm / ° C. And as a linear expansion coefficient of each metal thin film, it is preferable to set in the range of 3-15 ppm / degreeC, More preferably, it exists in the range of 4-10 ppm / degreeC. Examples of the metal material for such a metal thin film include titanium, tantalum, chromium, molybdenum, tungsten, platinum, ruthenium, osmium, rhodium, rhenium, iridium and the like. Among these, molybdenum (linear expansion coefficient 5.1 ppm / ° C.) and tungsten (linear expansion coefficient 4.5 ppm / ° C.) and tungsten (linear expansion coefficient 4.5 ppm / ° C.) are preferable from the viewpoint of relatively high hardness. It is preferable to use a thin metal material. In addition, each metal thin film which comprises the said lower electrode film 3 can be formed by sputtering method.

  Examples of the material for forming the dielectric film 4 include strontium titanate, barium titanate, magnesium titanate, zinc titanate, lanthanum titanate, neodymium titanate, lead titanate, barium zirconate titanate, and barium zirconate. , Calcium zirconate, lead zirconate, lead zirconate titanate, barium strontium titanate, titanium oxide, barium stannate, calcium stannate, magnesium silicate, alumina and the like. Moreover, it is preferable to set the thickness of the dielectric film 4 in the range of 0.1-0.5 micrometer, More preferably, it exists in the range of 0.15-0.4 micrometer. The dielectric film 4 can be formed by a sputtering method.

  Examples of the material for forming the upper electrode film 5 include platinum, palladium, ruthenium, ruthenium oxide, titanium, titanium nitride, rhodium, and aluminum. Further, the thickness of the upper electrode film 5 is preferably set in a range of 0.05 to 0.3 μm, and more preferably in a range of 0.05 to 0.2 μm. The upper electrode film 5 may be a single layer or a plurality of layers, and can be formed by a sputtering method.

  The material for forming the external electrodes 6 and 7 is not particularly limited, but usually copper is used and formed by electrolytic copper plating.

  Examples of the insulating material for the insulating layer 8 include polyimide, epoxy resin, cardo resin, and the like. The insulating layer 8 can be formed by applying the insulating material and curing it.

  Such a thin film capacitor can be manufactured as follows, for example.

  First, a roll body is prepared by winding the long metal substrate 1 formed in a strip shape into a roll shape. Although the dimension of the strip | belt-shaped elongate metal substrate 1 is not specifically limited, For example, it sets in the range of 50-350 mm in width, and the range of 50-300 m in length. Then, as shown in FIG. 2, the polyamic acid solution is applied onto the long metal substrate 1 by a casting method or the like while the long metal substrate 1 is fed out from the roll body in a strip shape, and then dried. Subsequently, the polyimide insulating layer 2 is formed by heating it to imidize.

  Next, as shown in FIG. 3, a metal thin film is sequentially laminated on the polyimide insulating layer 2 by a sputtering method to form a plurality of layers of metal thin films. Then, after a photoresist having a predetermined pattern is formed on the uppermost metal thin film, the metal thin film other than the photoresist is removed by etching. Thereafter, the photoresist is removed. Thereby, the lower electrode film 3 made of a plurality of layers of metal thin films formed in a predetermined pattern is formed.

  Next, as shown in FIG. 4, a material for forming the dielectric film 4 is laminated on the lower electrode film 3 by sputtering. Then, after a photoresist having a predetermined pattern is formed thereon, the material for forming the dielectric film 4 other than the photoresist is removed by etching. Thereafter, the photoresist is removed. Thereby, the dielectric film 4 formed in a predetermined pattern is formed.

  Next, as shown in FIG. 5, a material for forming the upper electrode film 5 is laminated on the dielectric film 4 by sputtering. Then, after a photoresist having a predetermined pattern is formed thereon, the material for forming the upper electrode film 5 in portions other than the photoresist is removed by etching. Thereafter, the photoresist is removed. Thereby, the upper electrode film 5 formed in a predetermined pattern is formed.

  Further, as shown in FIG. 6, after the insulating material is applied to the entire exposed surfaces of the polyimide insulating layer 2, the lower electrode film 3, the dielectric film 4 and the upper electrode film 5 by a spray coating method, a casting method or the like. Then, the insulating layer 8 is formed by curing. Then, through holes 8a and 8b are formed by etching or the like in portions of the insulating layer 8 corresponding to the lower electrode film 3 and the upper electrode film 5, and the surface of the lower electrode film 3 and the surface of the upper electrode film 5 are formed. Expose part.

  Next, it is immersed in a copper sulfate plating bath, and electrolytic copper plating is performed to form external electrodes 6 and 7 (see FIG. 1) made of copper plating in the through holes 8a and 8b, respectively. Then, the thin film capacitor forming portion is cut by punching or the like to obtain individual thin film capacitor pieces, and the remaining unnecessary portions are wound into a roll.

  Thus, in the thin film capacitor of the above embodiment, the lower electrode film 3 is formed by laminating a plurality of metal thin films, and among these metal thin films, the linear expansion coefficient of the thickest metal thin film and the length Since the difference from the linear expansion coefficient of the long metal substrate 1 is within 3 ppm / ° C., wrinkles and cracks are hardly generated even when the long metal substrate 1 is used. As a result, each thin film capacitor piece has good electrical characteristics.

  In the above embodiment, the lower electrode film 3 is formed by laminating a plurality of metal thin films, but may be formed of a single metal thin film. In this case, the difference between the linear expansion coefficient of the one-layer metal thin film and the linear expansion coefficient of the long metal substrate 1 is set within 3 ppm / ° C. In this case, the thickness of the one-layer metal thin film (the thickness of the entire lower electrode film 3) is preferably set in the range of 0.4 to 1.5 μm, more preferably 0.5 to 1. It is in the range of 0 μm. The linear expansion coefficient of the one-layer metal thin film is preferably set in the range of 3 to 12 ppm / ° C, more preferably in the range of 4 to 10 ppm / ° C.

  In the above embodiment, after forming the thin film capacitor, the long metal substrate 1 may be etched into a predetermined pattern as necessary.

  Next, examples will be described together with comparative examples.

  A thin film capacitor was formed in the same manner as in the above embodiment. In this formation, the materials and methods were as follows.

[Long metal substrate]
A roll body was prepared by winding a long metal substrate made of a band-shaped 42 alloy having a thickness of 50 μm, a width of 100 mm, and a length of 100 m into a roll shape. Then, a long metal substrate was drawn out from the roll body into a strip shape. The linear metal expansion coefficient of the long metal substrate made of the 42 alloy is 4.5 ppm / ° C.

[Polyimide insulation layer]
A polyamic acid solution was obtained by reacting 100 mol of pyromellitic dianhydride, 65 mol of m-toluylenediamine and 35 mol of 4,4'-diaminodiphenyl ether in N-methylpyrrolidinone (solvent). And this polyamic acid solution is apply | coated by the casting method on the long metal board | substrate which consists of the said 42 alloy extended | drawn out in the said strip | belt shape, and after drying at 80 degreeC x 30 minutes, it heats at 420 degreeC and imidizes. Thus, a polyimide insulating layer was formed. The linear expansion coefficient of this polyimide insulating layer was 6.8 ppm / ° C., and the measurement was performed using a thermomechanical analyzer (manufactured by Rigaku Corporation, TMA8310). The same).

[Lower electrode film]
Titanium (thickness 50 nm), molybdenum (thickness 1 μm), titanium (thickness 50 nm), and ruthenium (thickness 100 nm) were laminated in this order on the polyimide insulating layer by sputtering. And the lower electrode film of a predetermined pattern was formed by etching these laminated metal thin films. Of the metal thin films, the thickest molybdenum has a linear expansion coefficient of 5.1 ppm / ° C.

[Dielectric film]
With the lower electrode film heated to 300 ° C., strontium titanate (thickness 0.3 μm) was laminated on the lower electrode film by sputtering. Then, a dielectric film having a predetermined pattern was formed by etching it.

[Upper electrode film]
Titanium nitride (thickness: 0.1 μm) was laminated on the dielectric film by sputtering. And the upper electrode film of the predetermined pattern was formed by etching it.

[Insulating layer]
By applying a polyimide precursor (insulating material) to the entire exposed surface of the polyimide insulating layer, lower electrode film, dielectric film and upper electrode film by spray coating, and then imidizing by heating at 260 ° C. Cured to form an insulating layer. Then, through holes were formed in the insulating layer by etching to expose the surface of the lower electrode film and the surface of the upper electrode film.

[External electrode]
Electrolytic copper plating was performed in a copper sulfate plating bath, and external electrodes each made of copper plating were formed in the through holes.

  Then, the thin film capacitor forming portion was cut by punching to obtain individual thin film capacitor pieces, and the remaining unnecessary portions were wound into a roll.

  In the said Example 1, the polyamic acid solution which is a forming material of a polyimide insulating layer was as follows. The linear insulation coefficient of the formed polyimide insulating layer was 10.3 ppm / ° C. Other than that was the same as Example 1 above.

[Polyamic acid solution]
100 moles of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 100 moles of p-phenylenediamine were reacted in N-methylpyrrolidinone (solvent) to obtain a polyamic acid solution. Then, a polyimide insulating layer was formed in the same manner as in Example 1.

  In Example 1, the long metal substrate is made of 36 alloy (linear expansion coefficient 1.5 ppm / ° C.), and the metal material of the thickest metal thin film among the metal thin films constituting the lower electrode film part is tungsten. (Linear expansion coefficient 4.5 ppm / ° C.), and the difference between the two linear expansion coefficients was 3.0 ppm / ° C. Other than that was the same as Example 1 above.

  In the said Example 1, the polyamic acid solution which is a forming material of a polyimide insulating layer was as follows. The linear expansion coefficient of the formed polyimide insulating layer was 13.8 ppm / ° C. (the difference from the linear expansion coefficient of the long metal substrate was 9.3 ppm / ° C.). Other than that was the same as Example 1 above.

[Polyamic acid solution]
100 mol of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 85 mol of p-phenylenediamine and 15 mol of 4,4'-diaminodiphenyl ether were reacted in N-methylpyrrolidinone (solvent) to form a polyamic An acid solution was obtained. Then, a polyimide insulating layer was formed in the same manner as in Example 1.

  In the said Example 1, the polyamic acid solution which is a forming material of a polyimide insulating layer was as follows. The linear expansion coefficient of the formed polyimide insulating layer was 14.9 ppm / ° C. [The linear expansion coefficient (5.1 ppm / ° C.) of the thickest metal thin film (molybdenum) among the metal thin films constituting the lower electrode film And 9.8 ppm / ° C.]. Other than that was the same as Example 1 above.

[Polyamic acid solution]
A polyamic acid is prepared by reacting 100 mol of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 80 mol of p-phenylenediamine and 20 mol of 4,4'-diphenyl ether in N-methylpyrrolidinone (solvent). A solution was obtained. Then, a polyimide insulating layer was formed in the same manner as in Example 1.

[Comparative Example 1]
In Example 1, the long metal substrate is made of 36 alloy (linear expansion coefficient 1.5 ppm / ° C.), and the metal material of the thickest metal thin film among the metal thin films constituting the lower electrode film part is molybdenum. (Linear expansion coefficient 5.1 ppm / ° C.), and the difference between the two linear expansion coefficients was 3.6 ppm / ° C. Other than that was the same as Example 1 above.

[Wrinkles, cracks]
In Examples 1 to 5 and Comparative Example 1, when the lower electrode film and the dielectric film are observed with a microscope after the dielectric film is formed, in Examples 1 to 5, the lower electrode film and the dielectric film are wrinkled. There were no cracks. In contrast, in Comparative Example 1, wrinkles and cracks were generated. Further, the same results as described above were obtained when the lower electrode film and the dielectric film were observed with a microscope after the thin film capacitor forming portion was cut by punching. The results are also shown in Table 1 below.

[Electrical characteristics]
With respect to the individual thin film capacitor pieces (100 pieces each) obtained in Examples 1 to 5 and Comparative Example 1, the capacitance (F) and loss tan δ at a frequency of 10 kHz were measured. When the deviation of the capacitance from the design value is within ± 5% and the loss tan δ is 0.01 or less, it is judged as a non-defective product, and when the non-defective product rate is 95% or more, ◎, 85% or more and less than 95% The case of was evaluated as ◯, and the case of less than 85% was evaluated as ×, and was also shown in Table 1 below.

  From the results of Table 1 above, it can be seen that the thin film capacitors of Examples 1 to 5 are prevented from wrinkling and cracking, and thus have excellent electrical characteristics. In particular, in Examples 1 and 2, since the difference in linear expansion coefficient is small, the electrical characteristics are extremely excellent. In Example 3, since the difference in coefficient of linear expansion between the long metal substrate and the metal thin film having the thickest bottom electrode film part is a little as large as 3.0 ppm / ° C., the electrical characteristics are excellent. Less than 1 or 2. Also in Example 4, since the difference in coefficient of linear expansion between the long metal substrate and the polyimide insulating layer is a little as large as 10.0 ppm / ° C., the electrical characteristics are excellent, but it is as long as that of Examples 1 and 2. Absent. Also in Example 5, although the difference in linear expansion coefficient between the metal thin film having the largest thickness of the lower electrode film part and the polyimide insulating layer is a little large as 10.0 ppm / ° C., the electrical characteristics are excellent. It does not extend to Examples 1 and 2.

It is sectional drawing which shows one Embodiment of the thin film capacitor of this invention. It is explanatory drawing which shows the manufacturing method of the said thin film capacitor. It is explanatory drawing which shows the manufacturing method of the said thin film capacitor. It is explanatory drawing which shows the manufacturing method of the said thin film capacitor. It is explanatory drawing which shows the manufacturing method of the said thin film capacitor. It is explanatory drawing which shows the manufacturing method of the said thin film capacitor.

Explanation of symbols

1 Long metal substrate 2 Polyimide insulating layer 3 Lower electrode film 4 Dielectric film 5 Upper electrode film

Claims (4)

  A thin film capacitor in which a lower electrode film, a dielectric film, and an upper electrode film are laminated in this order on a polyimide insulating layer formed on a long metal substrate, wherein the lower electrode film is a plurality of laminated Of the metal thin film or a single metal thin film, and the linear expansion coefficient of the thickest metal thin film among the plurality of metal thin films constituting the lower electrode film or the linear expansion coefficient of the single metal thin film, and the length A thin film capacitor characterized in that a difference from a linear expansion coefficient of a long metal substrate is within 3 ppm / ° C.   The thin film capacitor according to claim 1, wherein a difference between a linear expansion coefficient of the polyimide insulating layer and a linear expansion coefficient of the long metal substrate is within 10 ppm / ° C.   The difference between the linear expansion coefficient of the polyimide insulating layer and the linear expansion coefficient of the thickest metal thin film among the plurality of metal thin films constituting the lower electrode film or the linear expansion coefficient of the one-layer metal thin film is 10 ppm / The thin film capacitor according to claim 1 or 2 which is within ° C.   The thin metal capacitor according to any one of claims 1 to 3, wherein the long metal substrate is an alloy of iron and nickel.

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