JP7347021B2 - Thin film LC filter and its manufacturing method - Google Patents

Description

The present invention relates to a thin film LC filter and a method for manufacturing the same, and in particular includes a capacitor insulating film made of an inorganic insulating material located between an upper capacitor electrode and a lower capacitor electrode, and an insulating resin layer embedding the upper capacitor electrode and the lower capacitor electrode. The present invention relates to a thin film LC filter and a method for manufacturing the same.

As a thin film LC filter including a capacitive insulating film made of an inorganic insulating material and an insulating resin layer in which a lower capacitive electrode is embedded, a thin film LC filter described in Patent Document 1 is known. In the thin film LC filter described in Patent Document 1, a lower electrode portion and an inorganic dielectric film are formed on a base substrate and a flattening film made of ceramic such as alumina, and an upper electrode portion is formed on the inorganic dielectric film. It has a similar structure. The unevenness formed by the lower electrode portion and the inorganic dielectric film is flattened by the organic insulating layer.

Japanese Patent Application Publication No. 2008-34626

However, in the LC filter described in Patent Document 1, since the lower electrode portion having irregularities is covered with a thin inorganic dielectric film, the stress applied to the inorganic dielectric film is concentrated at the corners, and in some cases, the stress applied to the inorganic dielectric film is concentrated at the corners. Cracks may occur.

Therefore, an object of the present invention is to prevent damage to the capacitive insulating film due to unevenness in a thin film LC filter including a capacitive insulating film made of an inorganic insulating material and a method for manufacturing the same.

A thin film LC filter according to the present invention has a first insulating resin layer having a first surface, a second insulating resin layer having a second surface, third and fourth surfaces, and a third insulating resin layer having a first surface. a flat capacitive insulation made of an inorganic insulating material disposed between a first insulating resin layer and a second insulating resin layer such that a surface is in contact with the first surface and a fourth surface is in contact with the second surface; a lower capacitor electrode embedded in the first insulating resin layer and in contact with a third surface of the capacitive insulating film; and an upper capacitor embedded in the second insulating resin layer and in contact with a fourth surface of the capacitive insulating film. It is characterized by comprising an electrode and an inductor pattern provided on the second insulating resin layer and connected to the lower capacitor electrode and the upper capacitor electrode.

According to the present invention, since the capacitive insulating film made of an inorganic insulating material is flat, it is possible to prevent the capacitive insulating film from being damaged due to unevenness.

In the present invention, the first insulating resin layer and the second insulating resin layer may be made of the same material. According to this, it is possible to prevent the occurrence of warpage due to a difference in thermal expansion coefficients.

In the present invention, the surface of the lower capacitor electrode in contact with the first insulating resin layer may be roughened. According to this, the adhesion between the lower capacitor electrode and the first insulating resin layer is improved. Alternatively, a protective insulating layer made of the same inorganic insulating material as the capacitive insulating film may be provided between the lower capacitive electrode and the first insulating resin layer. According to this, since almost the entire surface of the lower capacitor electrode is covered with the inorganic insulating material, the lower capacitor electrode is protected.

In the present invention, the surface of the upper capacitor electrode in contact with the second insulating resin layer may be roughened. According to this, the adhesion between the upper capacitor electrode and the second insulating resin layer is improved.

The thin film LC filter according to the present invention includes a third insulating resin layer in which an inductor pattern is embedded, a fifth surface of the first insulating resin layer located on the opposite side to the first surface, and a lower capacitor electrode. The device may further include a connected back terminal electrode and a top terminal electrode provided on the sixth surface of the third insulating resin layer located on the opposite side to the fifth surface and connected to the inductor pattern. I do not care. According to this, it is possible to obtain a terminal structure suitable for embedding in a circuit board.

In the present invention, the inductor pattern includes a coil pattern, and the upper capacitor electrode and the lower capacitor electrode may be provided at positions that do not overlap with the inner diameter portion of the coil pattern. According to this, the magnetic field generated by the coil pattern is less likely to interfere with the upper capacitor electrode and the lower capacitor electrode.

In the present invention, the upper capacitor electrode may be thicker than the lower capacitor electrode. According to this, when the upper capacitor electrode is used as it is as a part of the inductor pattern, it is possible to reduce the resistance value of the inductor pattern.

The method for manufacturing a thin film LC filter according to the present invention involves preparing a laminate having a structure in which both sides of a capacitive insulating film made of an inorganic insulating material are covered with a conductive film, and patterning one of the conductive films to form a lower capacitive electrode. After preparing the first insulating resin layer and laminating the laminate on the first insulating resin layer so that the lower capacitor electrode is embedded in the first insulating resin layer, the other conductor is formed. a second step of forming an upper capacitor electrode by patterning the film; a third step of forming a second insulating resin layer on the capacitor insulating film so that the upper capacitor electrode is embedded; The method is characterized by comprising a fourth step of forming an inductor pattern connected to the lower capacitor electrode and the upper capacitor electrode on the resin layer.

According to the present invention, since a capacitive insulating film whose both surfaces are covered with a conductive film is used, there is no need to form a capacitive insulating film on the uneven surface. This makes it possible to prevent damage to the capacitor insulating film due to unevenness. Moreover, after forming the lower capacitor electrode, the laminate is laminated on the first insulating resin layer so that the lower capacitor electrode is embedded in the first insulating resin layer. The supporting substrate used does not remain in the final product.

The method for manufacturing a thin film LC filter according to the present invention may further include a step of roughening the surface of the lower capacitor electrode after performing the first step and before performing the second step. According to this, the adhesion between the lower capacitor electrode and the first insulating resin layer is improved. Alternatively, after performing the first step and before performing the second step, the method may further include a step of covering the lower capacitor electrode with a protective insulating layer made of the same inorganic insulating material as the capacitor insulating film. According to this, since almost the entire surface of the lower capacitor electrode is covered with the inorganic insulating material, the lower capacitor electrode is protected.

The method for manufacturing a thin film LC filter according to the present invention may further include a step of roughening the surface of the upper capacitor electrode after performing the second step and before performing the third step. According to this, the adhesion between the upper capacitor electrode and the second insulating resin layer is improved.

The method for manufacturing a thin film LC filter according to the present invention includes the steps of forming a via that penetrates the first insulating resin layer and exposing the lower capacitor electrode, and forming a back terminal electrode connected to the lower capacitor electrode via the via. It may further include a step of forming. According to this, it is possible to obtain a terminal structure suitable for embedding in a circuit board.

The method for manufacturing a thin film LC filter according to the present invention further includes, before patterning one conductor film, forming a via conductor that penetrates the capacitive insulating film and connects one conductor film to the other conductor film. I don't mind. According to this, after the laminate is laminated on the first insulating resin layer, the step of forming vias in the capacitive insulating film is not necessary.

As described above, according to the present invention, in a thin film LC filter including a capacitive insulating film made of an inorganic insulating material and a method for manufacturing the same, it is possible to prevent damage to the capacitive insulating film due to unevenness.

FIG. 1 is a schematic cross-sectional view for explaining the structure of a thin film LC filter 1 according to a first embodiment of the present invention. FIG. 2 is a process diagram for explaining the method for manufacturing the thin film LC filter 1. As shown in FIG. FIG. 3 is a process diagram for explaining the method for manufacturing the thin film LC filter 1. As shown in FIG. FIG. 4 is a process diagram for explaining the method for manufacturing the thin film LC filter 1. As shown in FIG. FIG. 5 is a process diagram for explaining the method for manufacturing the thin film LC filter 1. As shown in FIG. FIG. 6 is a process diagram for explaining the method for manufacturing the thin film LC filter 1. As shown in FIG. FIG. 7 is a process diagram for explaining the method for manufacturing the thin film LC filter 1. As shown in FIG. FIG. 8 is a process diagram for explaining the method for manufacturing the thin film LC filter 1. As shown in FIG. FIG. 9 is a process diagram for explaining the method for manufacturing the thin film LC filter 1. As shown in FIG. FIG. 10 is a process diagram for explaining the method for manufacturing the thin film LC filter 1. As shown in FIG. FIG. 11 is a process diagram for explaining the method for manufacturing the thin film LC filter 1. As shown in FIG. FIG. 12 is a schematic cross-sectional view for explaining the structure of a thin film LC filter 2 according to the second embodiment of the present invention. FIG. 13 is a process diagram for explaining the method for manufacturing the thin film LC filter 2. As shown in FIG. FIG. 14 is a schematic cross-sectional view for explaining the structure of a thin film LC filter 3 according to the third embodiment of the present invention. FIG. 15 is a process diagram for explaining the method for manufacturing the thin film LC filter 3. As shown in FIG. FIG. 16 is a schematic cross-sectional view for explaining the structure of a thin film LC filter 4 according to the fourth embodiment of the present invention. FIG. 17 is a process diagram for explaining the method for manufacturing the thin film LC filter 4. As shown in FIG. FIG. 18 is a process diagram for explaining the method for manufacturing the thin film LC filter 4. As shown in FIG. FIG. 19 is a process diagram for explaining the method for manufacturing the thin film LC filter 4. As shown in FIG. FIG. 20 is a schematic cross-sectional view for explaining the structure of a thin film LC filter 5 according to the fifth embodiment of the present invention. FIG. 21 is a process diagram for explaining the method for manufacturing the thin film LC filter 5. As shown in FIG. FIG. 22 is a process diagram for explaining the method for manufacturing the thin film LC filter 5. As shown in FIG. FIG. 23 is a process diagram for explaining the method for manufacturing the thin film LC filter 5. As shown in FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<First embodiment>
FIG. 1 is a schematic cross-sectional view for explaining the structure of a thin film LC filter 1 according to a first embodiment of the present invention.

As shown in FIG. 1, the thin film LC filter 1 according to the first embodiment has a flat capacitor made of insulating resin layers 11 to 13 and an inorganic insulating material disposed between the insulating resin layer 11 and the insulating resin layer 12. It includes an insulating film D and wiring layers M1 to M5 and MM. The insulating resin layers 11 to 13 are made of a material in which a filler is added to a resin, and may be made of the same material or different materials. By using the same material as the materials constituting the insulating resin layers 11 to 13, it is possible to prevent warpage caused by differences in thermal expansion coefficients. The insulating resin layer 13 has a three-layer structure consisting of insulating resin layers 13a to 13c.

The capacitive insulating film D has a surface S3 and a surface S4 located on the opposite side thereof, and both of these surfaces S3 and S4 are flat. The capacitive insulating film D is arranged between the insulating resin layer 11 and the insulating resin layer 12 such that the surface S3 is in contact with the surface S1 of the insulating resin layer 11 and the surface S4 is in contact with the surface S2 of the insulating resin layer 12. be done. The capacitive insulating film D is a continuous film that is not patterned except for the portion through which the via conductor 30 penetrates. The inorganic insulating material constituting the capacitive insulating film D is selected from the group consisting of alumina, aluminum nitride, silica, silicon nitride, tantalum oxide, niobium oxide, titanium oxide, strontium titanate, barium strontium titanate, and lead zirconate titanate. It is preferable that at least one selected dielectric material is included.

On the surface S3 of the capacitive insulating film D, a lower capacitive electrode 20 belonging to the wiring layer M1 is formed. The lower capacitor electrode 20 is embedded in the insulating resin layer 11. Further, on the surface S4 of the capacitive insulating film D, an upper capacitive electrode 21 belonging to the wiring layer MM is formed. The upper capacitor electrode 21 is embedded in the insulating resin layer 12. The lower capacitor electrode 20 and the upper capacitor electrode 21 face each other with the capacitor insulating film D interposed therebetween, and this portion functions as a capacitor C. The thicknesses of the lower capacitor electrode 20 and the upper capacitor electrode 21 may be the same, but if the thickness of the upper capacitor electrode 21 is made larger than that of the lower capacitor electrode 20, the upper capacitor electrode 21 can be used as is. When used as part of an inductor pattern, it is possible to reduce the resistance value of the inductor pattern.

The wiring layers M2 to M5 are wiring layers located on the surfaces of the insulating resin layers 12, 13a, 13b, and 13c, respectively. Conductor patterns 22 to 25 are formed in the wiring layers M2 to M5, respectively. The conductor pattern 22 is connected to the lower capacitive electrode 20 via a via conductor 30 provided through the insulating resin layer 12 and the capacitive insulating film D, and is also connected to the via conductor 30 provided through the insulating resin layer 12. It is connected to the upper capacitor electrode 21 via a conductor 31. Further, the conductor pattern 23 is connected to the conductor pattern 22 through a via conductor 32 provided through the insulating resin layer 13a, and the conductor pattern 24 is connected through a via conductor 33 provided through the insulating resin layer 13b. The conductor pattern 25 is connected to the conductor pattern 24 through a via conductor 34 provided through the insulating resin layer 13c. The conductor patterns 22 to 25 constitute an inductor pattern, and this portion functions as an inductor L.

The inductor pattern includes a helically wound coil pattern, and the inner diameter portion A and the capacitor C are arranged at positions that do not overlap each other in a plan view. This reduces interference between the magnetic field generated by the current flowing through the coil pattern and the upper capacitor electrode 21 and the lower capacitor electrode 20, making it possible to suppress a decrease in inductance.

The conductor pattern 25 is exposed from the surface S6 of the insulating resin layer 13c, and is used as a terminal electrode of the thin film LC filter 1 according to this embodiment. Therefore, by turning the thin film LC filter 1 shown in FIG. 1 upside down, it becomes possible to surface-mount it on a circuit board using solder or the like.

In this way, in the thin film LC filter 1 according to this embodiment, the capacitive insulating film D made of an inorganic insulating material is flat. Therefore, unlike a general thin film LC filter in which a capacitive insulating film is formed on an uneven surface, strong stress is not applied to a specific location of the capacitive insulating film D, and cracks are less likely to occur in the capacitive insulating film D. Furthermore, since the capacitive insulating film D is a continuous film, the amount of patterning of the capacitive insulating film D can also be minimized.

Next, a method for manufacturing the thin film LC filter 1 according to this embodiment will be described.

2 to 11 are process diagrams for explaining the method for manufacturing the thin film LC filter 1. FIG.

First, as shown in FIG. 2, a capacitive insulating film D having conductive films formed on both surfaces is prepared. One of the conductor films is a wiring layer M1, and the other is a wiring layer MM. As a method for producing such a laminate, for example, a copper foil or a nickel foil constituting the wiring layer M1 is prepared, a capacitive insulating film D is formed on the surface thereof using a CVD method, and then a capacitive insulating film D is formed. A method of forming the wiring layer MM on the surface of the insulating film D using a plating method or the like can be mentioned. The laminate thus produced is mounted on the surface of the support substrate 41. At this time, the laminate is mounted on the surface of the support substrate 41 so that the wiring layer MM faces the support substrate 41 and the wiring layer M1 is exposed.

In this state, as shown in FIG. 3, the lower capacitor electrode 20 is formed by patterning the wiring layer M1. In the portion where the wiring layer M1 is removed, the surface S3 of the capacitive insulating film D is exposed. Thereafter, the surface of the lower capacitor electrode 20 is roughened using acid or the like.

Next, as shown in FIG. 4, the insulating resin layer 11 formed on the surface of the support substrate 42 is prepared, and the wiring layer M1, A stacked body consisting of a capacitive insulating film D and a wiring layer MM is stacked upside down. After that, the support substrate 41 is peeled off. As a result, as shown in FIG. 5, the surface S1 of the insulating resin layer 11 and the surface S3 of the capacitive insulating film D form the same flat plane, and the lower capacitive electrode 20 is embedded in the insulating resin layer 11. Become.

In this state, as shown in FIG. 6, the upper capacitor electrode 21 is formed by patterning the wiring layer MM. In the portion where the wiring layer MM is removed, the surface S4 of the capacitive insulating film D is exposed. Thereafter, the surface of the upper capacitor electrode 21 is roughened using acid or the like.

Next, as shown in FIG. 7, an insulating resin layer 12 is prepared, and the insulating resin layer 12 is laminated so that the surface S2 of the insulating resin layer 12 and the surface S4 of the capacitive insulating film D are in contact with each other. As a result, the surface S2 of the insulating resin layer 12 and the surface S4 of the capacitive insulating film D form the same flat plane, and the upper capacitive electrode 21 is embedded in the insulating resin layer 12. Thereafter, vias 30a and 31a are formed using a known method such as laser processing or blasting. The via 30a penetrates the insulating resin layer 12 and the capacitor insulating film D, and the lower capacitor electrode 20 is exposed on the bottom surface. Further, the via 31a penetrates the insulating resin layer 12, and the upper capacitor electrode 21 is exposed on the bottom surface.

Next, as shown in FIG. 8, a conductive material made of copper or the like is formed inside the vias 30a, 31a and on the surface S6 of the insulating resin layer 12 by performing electroless plating and electrolytic plating in this order. As a result, via conductors 30 and 31 are formed inside the vias 30a and 31a, respectively, and a wiring layer M2 is formed on the surface S7 of the insulating resin layer 12. Then, the conductor pattern 22 is formed by patterning the wiring layer M2.

Next, as shown in FIG. 9, the via conductor 32 and the wiring layer M3 are formed by laminating the insulating resin layer 13a, forming vias, and forming a conductive material by electroless plating and electrolytic plating. A conductive pattern 23 is formed by patterning. Similarly, as shown in FIG. 10, a via conductor 33 and a wiring layer M4 are formed by laminating an insulating resin layer 13b, forming a via, and forming a conductive material by electroless plating and electrolytic plating. A conductive pattern 24 is formed by patterning M4. Furthermore, as shown in FIG. 11, via conductors 34 and wiring layer M5 are formed by laminating an insulating resin layer 13c, forming vias, and forming a conductive material by electroless plating and electrolytic plating. A conductor pattern 25 is formed by patterning.

After peeling off the support substrate 42, the substrate is divided along dicing lines 43 shown in FIG. 11, thereby completing the thin film LC filter 1 shown in FIG.

As described above, in this embodiment, a capacitive insulating film D having conductive films formed on both sides is prepared, and after forming the lower capacitive electrode 20 by patterning, an insulating resin layer formed on another support substrate 42 is prepared. Since the capacitive insulating film D is laminated on 11, it is possible to eliminate the step of forming the capacitive insulating film on the uneven surface. Moreover, in the process shown in FIG. 4, since the laminate is turned upside down and laminated on the insulating resin layer 11, the support substrate 41 used when forming the lower capacitor electrode 20, etc. may remain in the final product. do not have. Furthermore, since the lower capacitor electrode 20 and the upper capacitor electrode 21 have roughened surfaces, the adhesion between the lower capacitor electrode 20 and the insulating resin layer 11 and the adhesion between the upper capacitor electrode 21 and the insulating resin layer 12 can also be improved. .

<Second embodiment>
FIG. 12 is a schematic cross-sectional view for explaining the structure of a thin film LC filter 2 according to the second embodiment of the present invention.

As shown in FIG. 12, in the thin film LC filter 2 according to the second embodiment, a protective insulating layer 14 made of the same inorganic insulating material as the capacitive insulating film D is provided between the lower capacitive electrode 20 and the insulating resin layer 11. This is different from the thin film LC filter 1 according to the first embodiment shown in FIG. Other basic configurations are the same as the thin film LC filter 1 according to the first embodiment, so the same elements are given the same reference numerals and redundant explanations will be omitted.

In the thin film LC filter 2 according to this embodiment, almost the entire surface of the lower capacitive electrode 20 is covered with an inorganic insulating material, so that the lower capacitive electrode 20 is more reliably protected. Here, although the protective insulating layer 14 is formed to have an uneven surface, even if a crack occurs in the protective insulating layer 14, the characteristics of the capacitor C are not affected.

When manufacturing the thin film LC filter 2 according to this embodiment, after performing the steps explained using FIGS. 2 and 3, as shown in FIG. The insulating layer 14 may be formed. Thereafter, by sequentially performing the steps explained using FIGS. 4 to 11, the thin film LC filter 2 according to this embodiment is completed.

<Third embodiment>
FIG. 14 is a schematic cross-sectional view for explaining the structure of a thin film LC filter 3 according to the third embodiment of the present invention.

As shown in FIG. 14, the thin film LC filter 3 according to the third embodiment includes a via conductor 35 provided through the insulating resin layer 11, and a back surface connected to the lower capacitor electrode 20 via the via conductor 35. This differs from the thin film LC filter 1 according to the first embodiment shown in FIG. 1 in that a terminal electrode 26 is provided. Other basic configurations are the same as the thin film LC filter 1 according to the first embodiment, so the same elements are given the same reference numerals and redundant explanations will be omitted.

The thin film LC filter 3 according to the present embodiment is provided with a back terminal electrode 26 in addition to the conductive pattern 25 constituting the top terminal electrode, so even when embedded in a circuit board, connections can be made from both sides. It is possible to take it.

When manufacturing the thin film LC filter 3 according to this embodiment, after performing the steps explained using FIGS. 2 to 11, as shown in FIG. Vias 35a are formed in the resin layer 11. The via 35a penetrates the insulating resin layer 11, and the lower capacitor electrode 20 is exposed on the bottom surface. Thereafter, by performing electroless plating and electrolytic plating in this order, a via conductor 35 is formed inside the via 35a, and a conductive material made of copper or the like is formed on the surface S5 of the insulating resin layer 11, and then patterning is performed. By doing this, the back terminal electrode 26 is formed. Thereby, the thin film LC filter 3 according to this embodiment is completed.

<Fourth embodiment>
FIG. 16 is a schematic cross-sectional view for explaining the structure of a thin film LC filter 4 according to the fourth embodiment of the present invention.

As shown in FIG. 16, in the thin film LC filter 4 according to the fourth embodiment, a conductor pattern 21a is provided in the wiring layer MM, and the conductor pattern 21a connects to the lower capacitor electrode 20 and the conductor pattern through via conductors 36 and 37, respectively. The thin film LC filter 1 is different from the thin film LC filter 1 according to the first embodiment shown in FIG. Other basic configurations are the same as the thin film LC filter 1 according to the first embodiment, so the same elements are given the same reference numerals and redundant explanations will be omitted.

In the thin film LC filter 4 according to this embodiment, the lower capacitive electrode 20 is connected to a conductor pattern 21a located in the wiring layer MM. Therefore, the step of forming vias in the capacitive insulating film D after inverting the stacked body and stacking it on the insulating resin layer 11 becomes unnecessary.

When manufacturing the thin film LC filter 4 according to this embodiment, as shown in FIG. 17, a capacitive insulating film D is formed on the surface of the wiring layer MM, and then the capacitive insulating film D is patterned to form vias 36a. When the wiring layer M1 is formed on the surface S3 of the capacitive insulating film D by performing plating in this state, the via 36a is filled with the via conductor 36, and the wiring layer M1 is formed through the via conductor 36, as shown in FIG. and wiring layer MM are short-circuited. Then, as shown in FIG. 19, a laminate including the wiring layer M1, the capacitive insulating film D, and the wiring layer MM is mounted on the surface of the support substrate 41. At this time, the laminate is mounted on the surface of the support substrate 41 so that the wiring layer MM faces the support substrate 41 and the wiring layer M1 is exposed.

After that, the thin film LC filter 4 according to this embodiment is completed by performing the steps explained using FIGS. 4 to 11.

<Fifth embodiment>
FIG. 20 is a schematic cross-sectional view for explaining the structure of a thin film LC filter 5 according to the fifth embodiment of the present invention.

As shown in FIG. 20, in the thin film LC filter 5 according to the fifth embodiment, the end portions of the capacitive insulating film D are removed, so that the insulating resin layer 11 and the insulating resin layer 12 are in contact with each other at the end portions. This is different from the thin film LC filter 1 according to the first embodiment shown in FIG. Other basic configurations are the same as the thin film LC filter 1 according to the first embodiment, so the same elements are given the same reference numerals and redundant explanations will be omitted.

In the thin film LC filter 5 according to this embodiment, since the capacitive insulating film D is not exposed to the outside, damage and deterioration of the capacitive insulating film D can be prevented.

When manufacturing the thin film LC filter 5 according to this embodiment, after performing the steps described using FIGS. 2 and 3, the end portions of the capacitive insulating film D are removed by patterning as shown in FIG. As shown in 22, the laminate consisting of the wiring layer M1, the capacitive insulating film D, and the wiring layer MM is stacked upside down so that the surface S1 of the insulating resin layer 11 and the surface S3 of the capacitive insulating film D are in contact with each other. Thereafter, as shown in FIG. 23, the support substrate 41 is peeled off. Thereafter, by sequentially performing the steps explained using FIGS. 6 to 11, the thin film LC filter 5 according to this embodiment is completed.

Further, if the thin film LC filter 5 according to this embodiment is manufactured and then cut along the broken line B shown in FIG. 20, the same structure as the thin film LC filter 1 shown in FIG. 1 can be obtained.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention. Needless to say, it is included within the scope.

1-5 Thin film LC filters 11-13, 13a, 13b, 13c Insulating resin layer 14 Protective insulating layer 20 Lower capacitor electrode 21 Upper capacitor electrode 21a, 22-25 Conductor pattern 26 Back terminal electrode 30-37 Via conductor 30a, 31a, 35a, 36a Via 41, 42 Support substrate 43 Dicing line A Inner diameter portion C Capacitor D Capacitive insulation film L Inductor M1 to M5, MM Wiring layer S1 to S7 Surface

Claims (10)

a first insulating resin layer having a first surface;
a second insulating resin layer having a second surface;
the first insulating resin layer and the first insulating resin layer have third and fourth surfaces, the third surface is in contact with the first surface, and the fourth surface is in contact with the second surface; a flat capacitive insulating film made of an inorganic insulating material disposed between the two insulating resin layers;
a lower capacitive electrode embedded in the first insulating resin layer and in contact with the third surface of the capacitive insulating film;
an upper capacitive electrode embedded in the second insulating resin layer and in contact with the fourth surface of the capacitive insulating film;
an inductor pattern provided on the second insulating resin layer and connected to the lower capacitor electrode and the upper capacitor electrode ,
A thin film LC filter characterized in that a protective insulating layer made of the same inorganic insulating material as the capacitive insulating film is provided between the lower capacitive electrode and the first insulating resin layer. The LC filter according to claim 1, wherein the first insulating resin layer and the second insulating resin layer are made of the same material. 3. The LC filter according to claim 1, wherein a surface of the upper capacitor electrode in contact with the second insulating resin layer is roughened. a third insulating resin layer embedding the inductor pattern;
a back terminal electrode provided on a fifth surface of the first insulating resin layer opposite to the first surface and connected to the lower capacitor electrode;
Claim further comprising: an upper surface terminal electrode provided on a sixth surface of the third insulating resin layer located on a side opposite to the fifth surface and connected to the inductor pattern. 4. The LC filter according to any one of 1 to 3 . the inductor pattern includes a coil pattern,
5. The LC filter according to claim 1, wherein the upper capacitor electrode and the lower capacitor electrode are provided at positions that do not overlap with an inner diameter portion of the coil pattern. 6. The LC filter according to claim 1 , wherein the upper capacitor electrode has a larger thickness than the lower capacitor electrode. A first step of preparing a laminate having a structure in which both sides of a capacitive insulating film made of an inorganic insulating material are covered with conductive films, and forming a lower capacitive electrode by patterning one of the conductive films;
After preparing a first insulating resin layer and laminating the laminate on the first insulating resin layer so that the lower capacitor electrode is embedded in the first insulating resin layer, the other conductive film is patterned. a second step of forming an upper capacitor electrode by
a third step of forming a second insulating resin layer on the capacitive insulating film so that the upper capacitive electrode is embedded;
a fourth step of forming an inductor pattern connected to the lower capacitor electrode and the upper capacitor electrode on the second insulating resin layer ,
After performing the first step and before performing the second step, the method further comprises the step of covering the lower capacitive electrode with a protective insulating layer made of the same inorganic insulating material as the capacitive insulating film. A method for manufacturing a thin film LC filter. 8. Manufacturing the LC filter according to claim 7 , further comprising the step of roughening the surface of the upper capacitor electrode after performing the second step and before performing the third step. Method. forming a via that penetrates the first insulating resin layer and exposes the lower capacitor electrode;
9. The method of manufacturing an LC filter according to claim 7 , further comprising the step of forming a back terminal electrode connected to the lower capacitor electrode via the via. 7. The method further comprises, before patterning the one conductor film, forming a via conductor that penetrates the capacitive insulating film and connects the one conductor film and the other conductor film. 10. The method for manufacturing an LC filter according to any one of 9 to 9 .

Images