JP4305173B2 - Electronic component and electronic device using the electronic component - Google Patents

Description

  The present invention relates to an electronic component and an electronic apparatus using the electronic component.

  Hereinafter, conventional electronic components will be described.

  In the conventional technique, a surface acoustic wave device (hereinafter referred to as “SAW device”) will be described as an example of an electronic component.

In recent years, small and light SAW devices are often used in electronic devices such as various mobile communication terminal devices. In particular, in a wireless circuit portion of a mobile phone system in the 800 MHz to 2 GHz band, a cutting angle of a lithium tantalate (hereinafter referred to as “LT”) substrate has a rotation angle of 36 ° around the X axis in the Z axis direction. A SAW filter produced using a so-called 36 ° Y-cut X-propagating LT substrate (hereinafter referred to as “36 ° YLT”) cut out from the Y plate is widely used. However, depending on the location of the filter used in the cellular phone system and its radio circuit, there is a need for a filter with a further low insertion loss in the passband, a steep filter skirt characteristic, and a high degree of suppression in the stopband. Yes. In order to satisfy such a requirement, the LT substrate is cut out from a Y plate whose rotation angle in the Z-axis direction around the X axis is 42 °. Patent Document 1 discloses a method for realizing a SAW filter having a lower loss and a sharper filter skirt characteristic than using a conventional 36 ° YLT substrate by using a substrate. Has been.
JP-A-9-167936

However, the 42 ° YLT substrate, like the conventional 36 ° YLT substrate, has a large coefficient of thermal expansion in the direction of propagation of the surface acoustic wave, and the elastic constant itself changes with temperature, so the frequency characteristics of the filter also change with temperature. However, there was a problem in the temperature characteristics, that is, a large shift of about -35 ppm / ^° K. For example, in the case of an American PCS transmission filter, a filter having a center frequency of 1.88 GHz at room temperature fluctuates by about ± 3.3 MHz, that is, about 6.6 MHz at room temperature ± 50 ° C. In the case of PCS, the interval between the transmission band and the reception band is only 20 MHz, and considering the frequency variation in manufacturing, the transmission / reception interval for the filter is substantially only about 10 MHz. For this reason, for example, when it is attempted to secure the transmission band at all temperatures (normal temperature ± 50 ° C.), there is a problem that the attenuation on the receiving side cannot be sufficiently obtained.

  The present invention solves the above-described conventional problems, and an object of the present invention is to obtain an electronic component having excellent temperature characteristics and electrical characteristics by forming a protective film on an electrode.

In order to achieve the above object, the first aspect of the present invention is an electronic component, and the protective film having a concavo-convex shape on the top surface provided on the electronic component is protected from the surface of the substrate in contact with the protective film. The height from the top of the convex part of the protective film to the top of the convex part of the protective film is t1, the height from the surface of the substrate in contact with the protective film to the bottom of the concave part of the protective film is t1. The height (t-t1) to the bottom of the concave portion is t2, the pitch width per pitch of the concave-convex shape of the protective film is L, and the width of the convex portion of the concave-convex portion per pitch of the concave-convex shape of the protective film is L1, the width of the recess L2, the pitch width per pitch of the comb-shaped electrode p, the width per electrode finger constituting the comb-shaped electrode p1, the width between the electrode fingers p2, the comb-shaped When the film thickness of the electrode is h,
t2 ≦ h
(However, the relation of L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, L2 ≧ p2 is satisfied), and the influence of the shape of the protective film on the electrode is reduced and unnecessary. By suppressing the occurrence of SAW reflection, as a result, even when the protective film is formed so as to cover the electrode and there is an uneven state on its surface, it is possible to obtain an electronic component with good characteristics. .

The second aspect of the present invention is an electronic component, and the protective film having a concavo-convex shape on the top surface provided on the electronic component is formed on the surface of the substrate in contact with the protective film from the surface of the convex portion of the protective film. The height to the top is t, the height from the surface of the substrate in contact with the protective film to the bottom of the concave portion of the protective film is t1, and the height from the top of the convex portion of the protective film to the bottom of the concave portion of the protective film The height (t-t1) is t2, the pitch width per pitch of the concavo-convex shape of the protective film is L, the width of the concavo-convex convex portion per pitch of the concavo-convex shape of the protective film is L1, and the width of the concave portion L2, the pitch width per pitch of the comb electrode, p, the width per electrode finger constituting the comb electrode p1, the width between the electrode fingers p2, the film thickness of the comb electrode h
h ≦ t2
(However, the relation of L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, L2 ≧ p2 is satisfied), and even when the protective film is formed so as to cover the electrode, By providing a difference in mass on the substrate between the electrode portion and the electrode finger, it is possible to suppress or improve the decrease in the reflection coefficient of the SAW at the electrode end, and as a result, a small and good-characteristic electron. It has the effect that parts can be obtained.

The third aspect of the present invention is an electronic component, and the protective film having a substantially flat top surface provided on the electronic component has a height from the substrate surface in contact with the protective film to the upper surface of the protective film. t, where the pitch width per pitch of the comb-shaped electrode is p, the substrate is a lithium tantalate substrate, and the cutting angle of the lithium tantalate substrate is in the Z-axis direction around the X-axis. When the angle of rotation is D °,
38 ° ≦ D °
Cut out from the Y plate, and
13% ≦ t / (2 × p) ≦ 35%
As a result, it is possible to obtain an electronic component with little change in temperature characteristics and good characteristics.

  As described above, according to the present invention, the protective film is formed so as to cover the electrode formed on the substrate, and the shape and thickness of the protective film are set within a specific range, whereby the temperature characteristics and electrical characteristics are set. An electronic component having excellent characteristics can be obtained.

  Hereinafter, electronic components according to embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a SAW device will be described as an example of an electronic component.

(Embodiment 1)
FIG. 1A is a top view of a SAW device as an electronic component according to Embodiment 1 of the present invention, and FIG.

  As shown in the figure, the SAW device of the first embodiment includes a comb-shaped electrode 2 on the upper surface of a substrate 1 and reflectors 3 on both sides of the comb-shaped electrode 2. A protective film 4 covering the vessel 3 is provided. Further, the comb-shaped electrode 2 has a pad 5 for taking out an electric signal electrically connected to the comb-shaped electrode 2, and constitutes a SAW device.

  The substrate 1 is made of lithium tantalate (hereinafter referred to as “LT”) cut from a Y plate rotated several degrees around the X axis in the Z axis direction, and the rotation angle is 36 °. It is a YLT substrate.

  The comb electrode 2 is made of aluminum (hereinafter referred to as “Al”) or an Al alloy.

The protective film 4 is preferably made of silicon dioxide (hereinafter referred to as “SiO ₂ ”), and has a concavo-convex shape on its top surface as shown in FIG. The convex portion 4 a of the protective film 4 is provided above the portion having the comb-shaped electrode 2 on the upper surface of the substrate 1. Further, the concave portion 4 b of the protective film 4 is provided in a portion where the comb-shaped electrode 2 between the convex portions 4 a does not exist on the upper surface of the substrate 1 and its vicinity.

  Here, the height from the surface of the substrate 1 that is in contact with the protective film 4 to the top of the convex portion 4a of the protective film 4 is t, and the surface of the substrate 1 that is in contact with the protective film 4 is The height from the bottom of the concave portion 4b of the protective film 4 to the top of the convex portion 4a (t-t1) is defined as t2.

  The height h of the comb-shaped electrode 2 is defined from the surface of the substrate 1 in contact with the protective film 4 to the top of the electrode finger 2a.

  Further, each of the convex portion 4a and the concave portion 4b of the protective film 4 is set to one pitch, the pitch width per pitch is L, the width of the convex portion 4a of the protective film 4 is L1, and the concave portion of the protective film 4 is provided. The width of 4b is assumed to be L2 (L = L1 + L2 holds). Similarly to the one pitch of the protective film 4, the portion between the electrode finger 2 a of one comb-shaped electrode 2 and the electrode finger 2 a adjacent to one side is defined as one pitch width p of the comb-shaped electrode 2.

  In addition, the width per electrode finger 2a is p1, and the width between adjacent electrode fingers is p2 (p = p1 + p2 holds).

  Further, the ratio L1 / L between the pitch width L of the protective film 4 and the width L1 of the convex portion 4a of the protective film 4 is η ′, and the one pitch width p of the comb-shaped electrode 2 and the width p1 per electrode finger Let the ratio p1 / p be η.

  A manufacturing method of the SAW device configured as described above will be described below with reference to the drawings.

  FIG. 2 is a diagram for explaining a method for manufacturing a SAW device according to Embodiment 1 of the present invention.

  First, as shown in FIG. 2A, an electrode film 22 to be a comb electrode or / and a reflector is formed on the upper surface of the LT substrate 21 by a method such as vapor deposition or sputtering of Al or an Al alloy.

  Next, as illustrated in FIG. 2B, a resist film 23 is formed on the upper surface of the electrode film 22.

  Next, as shown in FIG. 2C, the resist film 23 is processed using an exposure / development technique or the like so as to obtain a desired shape.

  Next, as shown in FIG. 2D, the electrode film 22 is processed into a desired shape such as a comb electrode or a reflector by using a dry etching technique or the like, and then the resist film 23 is removed.

Next, as shown in FIG. 2E, a protective film 24 is formed by a method such as vapor deposition or sputtering of SiO ₂ so as to cover the electrode film 22.

  Next, as shown in FIG. 2F, a resist film 25 is formed on the surface of the protective film 24.

  Next, as shown in FIG. 2G, the resist film 25 is processed into a desired shape using exposure, development techniques, and the like.

  Next, as shown in FIG. 2 (h), by using a dry etching technique or the like, a portion of the protective film that does not require the protective film 24, such as the pad 26 for extracting an electric signal, is removed, and then the resist film 25 is removed. To do.

  Finally, each was divided by dicing, and then mounted on a ceramic package by die bonding or the like. After wire bonding, the lid was welded and hermetically sealed.

In Embodiment 1 of the present invention,
t2 ≦ h
(However, the relationship of L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, L2 ≧ p2 is satisfied).

As a method for obtaining a shape satisfying this relationship, a so-called Bias sputtering method was used in which a film was formed by sputtering while applying a bias to the substrate side in forming the SiO ₂ film in FIG. At that time, the shape of the SiO ₂ film was controlled by changing the ratio of the bias applied to the substrate and the sputtering power.

In the first embodiment, the protective film is formed by changing the relationship between the height t2 from the top of the convex portion of the protective film to the bottom of the concave portion of the protective film and the film thickness h of the electrode. In order to show whether good characteristics can be obtained even in the case, as Example 1 and Comparative Example 2, t2 ≦ h (where L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, L2 SAW device satisfying the relationship of ≧ p2 and Comparative Example 1 satisfying the relationship of h <t2 (where L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, L2 ≧ p2) ) SAW device was prepared and its electrical characteristics were measured. However, the normalized film thickness (h / 2 × p) of the electrode film of Example 1 and Comparative Example 1 is 7%, and the normalized film thickness (h / 2 × p) of the electrode film of Comparative Example 2 is 4%. The SiO ₂ film thickness t1 was 20% in both Example 1 and Comparative Examples 1 and 2. Further, the created SAW device includes the ladder-type SAW shown in FIG. 3 formed by connecting the SAW resonator shown in FIG. 1A and the SAW resonator having the structure shown in FIG. It is a filter. In FIG. 3, 31 is an LT substrate, 32 is a SiO ₂ film, 34 is an electrode pad, 33s is a SAW resonator disposed on a series arm, and 33p is a SAW resonator disposed on a parallel arm.

  FIG. 4A shows the electrical characteristics of the SAW resonator of Example 1 according to the embodiment of the present invention, and FIG. 4B shows the electrical characteristics of the SAW filter. FIG. 5A shows the electrical characteristics of the SAW resonator of Comparative Example 1, FIG. 5B shows the electrical characteristics of the SAW filter of Comparative Example 1, and FIG. 6 shows the electrical characteristics of the SAW resonator of Comparative Example 2. FIG. 6 (b) shows the electrical characteristics of the SAW filter of Comparative Example 2 (a). However, as for the electrical characteristics, in order to consider the frequency deviation between the devices and to easily understand the difference in characteristics between the devices, the resonator characteristics are anti-resonant frequencies, and the SAW filter is the high-frequency attenuation pole. Standardized at a frequency of Further, Table 1 shows structural parameters of each example and comparative example.

  From the characteristics of the SAW resonator shown in FIGS. 4A to 6A, t2 ≦ h (where L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, It can be seen that the SAW resonators of Example 1 and Comparative Example 2 satisfying the relationship of L2 ≧ p2 have large attenuation and steep characteristics. Further, in the SAW resonators of Example 1 and Comparative Example 1 in which the normalized film thickness of the electrode is 7%, spurious generated on the high frequency side of the antiresonance frequency is far from the antiresonance frequency, whereas the electrode standard In the SAW resonator of Comparative Example 2 having a chemical film thickness of 4%, this spurious exists more near the antiresonance frequency. Similarly, when comparing the characteristics of the SAW filter, Example 1 in which t2 ≦ h (where L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, and L2 ≧ p2) is satisfied. The SAW filter of Comparative Example 2 shows a steep skirt characteristic. However, in the SAW filter in which the normalized film thickness of the electrode of Comparative Example 2 shown in FIG. 6B is 4%, ripples due to the ripple of the resonator are generated in the band. On the other hand, in the SAW filters of Example 1 and Comparative Example 1 having an electrode thickness of 7%, ripples are present outside the band, and no unnecessary ripples are observed within the band.

Therefore, in a filter in which a SAW resonator is connected to a multi-stage ladder type, unless a ripple generated on the higher frequency side than the anti-resonance frequency of the SAW resonator constituting the filter appears as a ripple in the filter band, In order to achieve a steep filter skirt characteristic and obtain high suppression with low loss, the shape of the SiO ₂ of the SAW resonator constituting the filter is t2 ≦ h (where L≈p, p1 + p2 = The inventors have found that it is preferable that the relationship of p, L1 + L2 = L, L1 ≦ p1, and L2 ≧ p2 is satisfied.

From these examples and comparative examples, the frequency difference between the anti-resonance frequency and the frequency at which the ripple generated in the SAW resonator on the higher frequency side than the anti-resonance frequency is equal to the film thickness of the electrode and the structure of the SiO ₂ film. It is thought that it depends on. Therefore, the inventors further satisfy the case where the structure of SiO ₂ satisfies t2 ≦ h (where L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, L2 ≧ p2). In addition, in order to investigate the preferred electrode film thickness, the electrode normalized film thickness h / (2 × p) is 3, 5, 7, 10%, and the SiO ₂ normalized film thickness t1 / (2 × p) is SAW resonators were created for the cases of 10, 15, and 20%, and the relationship with the ripple generation frequency was examined. The result is shown in FIG. However, as the structure of SiO _2, a structure of t≈t 1 in which the ripple of the resonator seems to be closest to the anti-resonance frequency was prepared.

  Here, the relationship between the frequency of occurrence of the ripple of the resonator and the characteristics of the filter will be considered using the simplest inverted L-type ladder filter shown in FIG. In FIG. 8, reference numeral 80 denotes a filter configuration, 81 is a filter characteristic, 82 is a SAW resonator arranged in a parallel arm, 83 is a SAW resonator arranged in a series arm, and 82a is arranged in a parallel arm. An admittance characteristic 83a of the SAW resonator formed is an admittance characteristic of the SAW resonator arranged in the series arm. An area 86 indicates the pass band of the filter. In the ladder-type SAW filter, the parallel resonance frequency of the series arm resonator and the resonance frequency of the series arm are set approximately at the center of the band, and the characteristic of the series arm resonator 83 is set on the high frequency side of the band on the low frequency side of the band. Then, the characteristic of the parallel arm 82 becomes dominant. Therefore, in order to prevent the ripple generated on the high frequency side from the anti-resonance frequency of the SAW resonator from affecting the pass band of the filter, the ripple generated in the resonator of the series arm does not enter the filter band. It is necessary to. Therefore, in this case, among the SAW resonators constituting the filter, regarding the ripple generation frequency in the SAW resonator of the series arm, (ripple generation frequency−anti-resonance frequency) is not less than (pass band of the filter / 2). It will be a guide. Considering that the pass band required for a filter for a normal mobile communication is about 0.3 to 0.4 in a specific band, the value of the reference (ripple generation frequency-antiresonance frequency) is 0. Therefore, it can be seen from FIG. 7 that the normalized film thickness of the electrode is preferably 5% or more.

As described above, in a filter in which SAW resonators are connected in a multi-stage ladder type, a ripple generated on the higher frequency side than the antiresonant frequency of the SAW resonator constituting the filter appears as a ripple in the band of the filter. Unless otherwise, to achieve a steep filter skirt characteristic and obtain high suppression with low loss, the shape of the SiO ₂ of the SAW resonator constituting the filter is t2 ≦ h (where L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, L2 ≧ p2 is satisfied), and the normalized film thickness h / (2 × p) of the electrode is 0.05 or more. The inventors have found that it is preferable.

In the first embodiment, the SiO ₂ film is used as the protective film. However, the protective film is not limited to this, and the shape of the protective film can be obtained even when other dielectric films such as SiN, SiON, Ta ₂ O ₅ are used. Needless to say, if the above condition is satisfied, the same effect can be obtained. In Embodiment 1, 36 ° YLT is used as the substrate. However, the substrate is not limited to this, and LT cut out at other angles, such as LiNbO ₃ , LiB ₂ O ₃ , When a protective film is formed on the surface of a SAW device using another piezoelectric substrate such as KNbO ₃ or an electrode formed on the piezoelectric film, the same effect can be obtained if the shape satisfies the above conditions. Needless to say, you can get

  Further, although bias sputtering is used in the first embodiment as a shape forming method, this is not limited to this method.

(Embodiment 2)
Hereinafter, a SAW device according to Embodiment 2 of the present invention will be described with reference to the drawings.

  In the second embodiment, the SAW device similar to the first embodiment is used as the SAW device. FIG. 9 is a cross-sectional view of the SAW device according to the second embodiment of the present invention. In this figure, the same components as those in FIG. 1B used in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

The protective film 4 is preferably made of SiO ₂ , and its top surface has an uneven shape as shown in FIG. The convex portion 94 a of the protective film 4 is provided above the portion having the comb-shaped electrode 2 on the upper surface of the substrate 1. Further, the concave portion 94b of the protective film 4 is provided in a portion where the comb-shaped electrode 2 between the convex portions 94a does not exist on the upper surface of the substrate 1 and its vicinity.

  Here, the height from the surface of the substrate 1 that is in contact with the protective film 4 to the top of the convex portion 94a of the protective film 4 is t, and the surface of the substrate 1 that is in contact with the protective film 4 is The height to the bottom of the concave portion 94b is t1, and the height t-t1 from the bottom of the concave portion 94b of the protective film 4 to the top of the convex portion 94a is t2.

  Further, each of the convex portion 94a and the concave portion 94b of the protective film 4 is set to one pitch, the pitch width per pitch is L, the width of the convex portion 94a of the protective film 4 is L1, and the concave portion of the protective film 4 is provided. The width of 94b is L2 (L = L1 + L2 holds).

  1B of the first embodiment is different from the bottom of the concave portion 4b of the protective film 4 of FIG. 1B of the first embodiment to the top of the convex portion 4a. 9 is equal to or less than the height h of the comb-shaped electrode 2, whereas in FIG. 9 of the second embodiment of the present invention, the height from the bottom of the concave portion 94 b of the protective film 4 to the top of the convex portion 94 a The difference is that t2 is not less than the height h of the comb-shaped electrode 2.

In Embodiment 2 of the present invention,
h ≦ t2
(However, the relationship of L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, L2 ≧ p2 is satisfied).

  As a method for obtaining a shape satisfying this relationship, the manufacturing method will be described below with reference to the drawings. In this figure, the same reference numerals are used for the same materials and configurations as those in FIG. 2 used in Embodiment 1, and the description thereof is omitted.

  FIG. 10 is a diagram for explaining a method for manufacturing a SAW device according to the second embodiment of the present invention.

  First, as shown in FIG. 10A, an electrode film 22 to be a comb-shaped electrode or / and a reflector is formed on the upper surface of the LT substrate 21 by a method such as vapor deposition or sputtering of Al or an Al alloy.

Next, as shown in FIG. 10 (b), forming part 24a of the protective film 24 by a method such as vapor deposition or sputtering SiO _2.

  Next, as shown in FIG. 10C, a resist film 23 is formed on the upper surface of the electrode film 24a.

  Next, as shown in FIG. 10D, the resist film 23 is processed using an exposure / development technique or the like so as to have a desired shape.

Next, as shown in FIG. 10E, the electrode film 22 and the protective film 24a are processed into a desired shape such as a comb-shaped electrode or a reflector by using a dry etching technique or the like, and then the resist film 23 is removed. . At this time, the etching of SiO _{2 and} the etching of the electrode film were performed by changing the etching gas from a fluorine-based gas to a chlorine-based gas on the way.

Next, as shown in FIG. 10F, a protective film 24 is formed by a method such as vapor deposition or sputtering of SiO ₂ so as to cover the electrode film 22 and the protective film 24a. At this time, the protective film 24 a becomes a part of the protective film 24.

  Next, as shown in FIG. 10G, a resist film 25 is formed on the surface of the protective film 24.

  Next, as shown in FIG. 10H, the resist film 25 is processed into a desired shape by using exposure, development technology, or the like.

  Next, as shown in FIG. 10 (i), using a dry etching technique or the like, a portion of the protective film that does not require the protective film 24, such as the pad 26 for extracting an electric signal, is removed, and then the resist film 25 is removed. To do.

  Finally, each was divided by dicing, and then mounted on a ceramic package by die bonding or the like. After wire bonding, the lid was welded and hermetically sealed.

In the second embodiment, the SiO _{2 in} FIG. 10 (f) is formed so that the shape satisfies the relations L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, L2 ≧ p2. For film formation, a SiO ₂ film was formed using a so-called Bias-sputtering method in which film formation was performed while applying an RF bias to the substrate side.

In the second embodiment, the protective film is formed by changing the relationship between the height t2 from the top of the convex portion of the protective film to the bottom of the concave portion of the protective film and the film thickness h of the electrode. In addition to Example 2 created by the manufacturing method shown in FIG. 10 in order to show whether good characteristics can be obtained in some cases, Comparative Example 3 in which no SiO ₂ film is formed and the manufacturing method shown in FIG. And the electrical characteristic was investigated about three types of SAW devices of the comparative example 4 produced using Bias-sputtering in FIG.2 (e).

However, in the second embodiment, the normalized film thickness h / (2 × p) of the electrodes of each SAW device is 4%, and the normalized film thickness of the SiO ₂ normalized film thickness t1 / (2 × p) is 20 %.

  FIG. 11A shows the electrical characteristics of the SAW resonator of the second example according to the embodiment of the present invention, and FIG. 11B shows the electrical characteristics of the SAW filter of the second example. 12A shows the electrical characteristics of the SAW resonator of Comparative Example 3, FIG. 12B shows the electrical characteristics of the SAW filter of Comparative Example 3, and FIG. 13A shows the SAW resonator of Comparative Example 4. FIG. 13B shows the electrical characteristics of the SAW filter of Comparative Example 4. The SAW resonator used in the second embodiment is a SAW resonator having the same configuration as that shown in FIG. 1A, and the SAW filter has the configuration shown in FIG. In FIG. 11 to FIG. 13, the electrical characteristics are considered to be the anti-resonance frequency with respect to the resonator characteristics and the SAW filter in order to take account of the frequency shift between the devices and to easily understand the difference in characteristics between the devices. Is normalized by the frequency of the attenuation pole on the high frequency side. Furthermore, the structural parameters of these examples and comparative examples are shown in Table 2.

As can be seen from FIG. 12 (a), the SAW device used in the second embodiment has a normalized film thickness of 4%, which is smaller than the antiresonance frequency even in the absence of SiO _2. Ripple generated on the high frequency side is generated relatively close to the anti-resonance frequency. Further, comparing the characteristics of the SAW resonator of Comparative Example 3 in FIG. 12 and Comparative Example 4 in FIG. 13, the ripple generated on the higher frequency side than the antiresonance frequency is more due to the formation of the SiO ₂ film. You can see that it is closer to the side. Therefore, in the characteristics of the SAW filter configured using the resonator of the comparative example 3 in which the SiO ₂ film is not formed as shown in FIG. 12B, the ripple that is barely present outside the passband is compared. In Example 4, as shown in FIG. 13B, it can be seen that it occurs in the passband. On the other hand, in Example 2, it can be seen from FIG. 11A that the ripple is shifted to the high frequency side. This is considered to be because by setting h ≦ t2, the thickness of the electrode apparently increased due to SiO ₂ formed on the electrode. As a result, no ripple is generated in the passband in the SAW filter shown in FIG. 11B and configured using the SAW resonator of FIG.

As described above, in a filter in which SAW resonators are connected in a multi-stage ladder type, a ripple generated on the higher frequency side than the anti-resonance frequency of the SAW resonator constituting the filter does not appear as a ripple in the filter band. As a technique for this, the shape of SiO ₂ of the SAW resonator constituting the filter is expressed as h ≦ t2 (where L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, L2 ≧ p2) The inventors have found that it is sufficient to satisfy. In particular, since the reflection coefficient greatly affects the film thickness of the electrode, when the electrode film thickness is thin, especially when using a resonator having an electrode film thickness of 5% or less from the consideration of FIG. 7 in the first embodiment. It is valid.

(Embodiment 3)
FIG. 14 is a cross-sectional view of a SAW device as an electronic component according to Embodiment 3 of the present invention. The top view is the same as FIG.

  As shown in FIG. 1A and FIG. 14, the SAW device according to the third embodiment includes a comb-shaped electrode 2 on the upper surface of a substrate 1 and reflectors 3 on both sides of the comb-shaped electrode 2. A protective film 4 covering the comb-shaped electrode 2 and the reflector 3 is provided. Further, the comb-shaped electrode 2 has a pad 5 for taking out an electric signal electrically connected to the comb-shaped electrode 2, and constitutes a SAW device.

  The substrate 1 is made of lithium tantalate cut out from a Y plate rotated several degrees around the X axis in the Z axis direction, and is a 36 ° YLT substrate whose rotation angle is 36 °.

  The comb electrode 2 is made of aluminum (hereinafter referred to as “Al”) or an Al alloy.

The protective film 4 is preferably made of silicon dioxide (hereinafter referred to as “SiO ₂ ”), and its upper surface has an uneven shape as shown in FIG. The convex portion 4 a of the protective film 4 is provided above the portion having the comb-shaped electrode 2 on the upper surface of the substrate 1. Further, the concave portion 4 b of the protective film 4 is provided in a portion where the comb-shaped electrode 2 between the convex portions 4 a does not exist on the upper surface of the substrate 1 and its vicinity.

  Here, each of the convex portion 4a and the concave portion 4b of the protective film 4 is one pitch, the pitch width per pitch is L, the width of the convex portion 4a of the protective film 4 is L1, and the protective film 4 The width of the concave portion 4b is L2 (L = L1 + L2 is established). Similarly to the one pitch of the protective film 4, the portion between the electrode finger 2 a of one comb-shaped electrode 2 and the electrode finger 2 a adjacent to one side is defined as one pitch width p of the comb-shaped electrode 2. Furthermore, the width per electrode finger 2a is p1, and the width between adjacent electrode fingers is p2 (p = p1 + p2 holds). Furthermore, a ratio L1 / L between the pitch width L of the protective film per pitch and the width L1 of the convex / concave portion of the concave / convex shape of the protective film is η ′, and the comb electrode per pitch Let η be the ratio p1 / p between the pitch width p and the width p1 per electrode finger constituting the comb electrode.

  The height from the surface of the substrate 1 in contact with the protective film 4 to the concave portion 4b of the protective film 4 is t, and the thickness of the comb electrode 2 (from the surface of the substrate 1 to the top surface of the comb electrode 2) H).

  The SAW device manufacturing method according to Embodiment 3 of the present invention is the same as that shown in FIG.

In Embodiment 3 of the present invention, the shape of the electrode and the SiO ₂ film is as follows:
L1 ≦ p1 and L2 ≧ p2
(However, the relationship of L≈p, p1 + p2 = p, and L1 + L2 = L is satisfied).

As a method for obtaining a shape satisfying this relationship, a so-called Bias sputtering method was used in which a film was formed by sputtering while applying a bias to the substrate side in forming the SiO ₂ film in FIG. At that time, the shape of the SiO ₂ film was controlled by changing the ratio of the bias applied to the substrate and the sputtering power.

In the third embodiment, the following six types of SAW devices (Examples) are shown in order to show how the shape of the SiO ₂ film can provide good characteristics even when a protective film is formed. 3-5 and Comparative Examples 5-7) were prepared. Comparative Example 5 is a normal SAW device not provided with an SiO ₂ film, Comparative Example 6 is a SAW device using normal sputtering in which SiO ₂ film is formed (Bias is not applied to the substrate side), and Comparative Example 7 is an SiO ₂ film. Bias sputtering was used to form the film, but the ratio of the bias applied to the substrate and the sputtering power was changed, and the SiO ₂ film was formed so that L1 ≧ p1 and L2 ≦ p2. However, in the third embodiment, the normalized film thickness h / (2 × p) of the electrodes in all Examples and Comparative Examples is 4%, and the normalized film thickness t / (2 × p) of the SiO ₂ film. ) Was 20%. FIG. 15 shows the cross-sectional shapes of Examples 3 to 5 and Comparative Examples 6 and 7, and FIG. 16 shows the electrical characteristics. In addition, the frequency difference between the resonance frequency and the anti-resonance frequency, which is an index of the minimum insertion loss and the attenuation amount (maximum attenuation amount) at the anti-resonance point, the steepness, of each of the examples and comparative examples shown in FIG. FIG. 16 shows a list of ratios η ′ / η of η and η ′ measured from the cross-sections of the respective SAW devices shown in FIG.

At this time, the cross-sectional shape of the SAW device is specified from the result of cutting the electrode in the SAW propagation direction by FIB (Focused Ion Beam) after coating the surface of the SAW device with metal and observing it with an electron microscope. did. However, as in the cross-sectional shape of the electrode shown in FIG. 26A, for example, the top part 141 of the convex portion of the SiO ₂ is substantially point-like and rounded in a curved shape from the top part to the bottom part of the convex part. When the boundary between L1 and L2 is unclear, as shown in FIG. 26 (b), the bottom-to-top edge is approximated by a curve 142 in the vicinity of the top of the convex portion, and the convexity of the curve a tangent 143 at the top 141 of the parts, defining L1 and L2 using the intersection 145 between a line 144 connecting the bottom of the next fit SiO _2. Further, when the convexity is small and L1 and L2 cannot be defined by this definition, or when the distance between L1 and L2 is longer than the electrode width p1, the shape of the SiO ₂ film is determined to be substantially flat.

16 and Table 3, the shape of the SiO ₂ film satisfies the relationship of “L1 ≦ p1 and L2 ≧ p2 (where L≈p, p1 + p2 = p, and L1 + L2 = L are satisfied)”. In Comparative Examples 6 and 7, the anti-resonance frequency attenuation is about -20 dB, and it can be seen from the comparison with the attenuation of Comparative Example 5 that SiO ₂ is greatly deteriorated. On the other hand, in Examples 3, 4 and 5 in which the shape of the SiO ₂ film satisfies the above relationship, the amount of attenuation at the antiresonance frequency is approximately −25 dB or more, which is substantially equivalent to that of Comparative Example 5. In particular, when Examples 3, 4 and 5 are compared, the amount of attenuation increases sharply in the order of Examples 3, 4 and 5, and in Examples 4 and 5, the attenuation is -26 dB or more before the SiO ₂ film is formed. It is shown that it is almost equivalent.

FIG. 17 is a graph showing the relationship between the maximum attenuation and η ′ / η. From this graph, it can be seen that the attenuation is improved as η ′ / η decreases. Especially 0.86 or less, has a 90% attenuation of the case of not forming the SiO _2, even after the formation of the SiO ₂ film, it is possible to obtain approximately the same performance as the previous SiO ₂ film formed it can.

As described above, the inventors set the shape of the SiO ₂ film as “L1 ≦ p1 and L2 ≧ p2 (where L≈p, p1 + p2 = p, L1 + L2 = L are satisfied)” It was found that good characteristics can be obtained even when a protective film is formed by forming the film so as to satisfy the above. In particular, it has been found that by setting η ′ / η ≦ 0.86, an attenuation amount equivalent to that when the protective film is not formed is realized.

In the third embodiment, the SiO ₂ film is used as the protective film. However, the protective film is not limited to this, and the shape can be obtained even when other dielectric films such as SiN, SiON, Ta ₂ O ₅ are used. Needless to say, if the above condition is satisfied, the same effect can be obtained. In Embodiment 3, 36 ° YLT is used as the substrate. However, the substrate is not limited to this, and LT cut out at other angles, such as LiNbO ₃ , LiB ₂ O ₃ , When a protective film is formed on the surface of a SAW device using another piezoelectric substrate such as KNbO ₃ or an electrode formed on the piezoelectric film, the same effect can be obtained if the shape satisfies the above conditions. Needless to say, you can get

  Further, although bias sputtering is used in the third embodiment as a shape forming method, this is not limited to this method.

(Embodiment 4)
Hereinafter, a SAW device according to Embodiment 4 of the present invention will be described with reference to the drawings.

  The SAW device in the fourth embodiment is the same SAW device as the SAW device used in the third embodiment although the number of electrodes and reflectors and the pitch p are different. Therefore, the structure and the creation method are the same as those shown in FIGS. 1A, 14 and 2, and the description thereof is omitted. The SAW device according to the fourth embodiment also satisfies the relationship “L1 ≦ p1 and L2 ≧ p2 (where L≈p, p1 + p2 = p, and L1 + L2 = L are satisfied)”.

  In the fourth embodiment, a protective film having the shape shown in the third embodiment and the positional relationship between the convex-concave convex center Lc of the protective film and the electrode pc center pc of the comb electrode is formed. In order to show the relationship with the electrical characteristics of the SAW device, as Example 6, a SAW device in which the convexity center Lc of the unevenness of the protective film and the center pc of the electrode finger of the comb electrode are substantially in a straight line As a comparative example 8, a SAW device in which the convex / concave convex center Lc of the protective film and the center pc of the electrode fingers of the comb-shaped electrode are shifted is produced. 18A shows the cross-sectional shape of the device of Example 6, FIG. 19A shows the cross-sectional shape of the device of Comparative Example 7, FIG. 18B shows the device of Example 6, and FIG. 19B shows the device of Comparative Example 8. The electrical characteristics of are shown. However, in FIGS. 18 (b) and 19 (b), in order to take into account the frequency shift between devices and to make it easy to understand the difference in characteristics between the devices, the SAW devices are normalized with the anti-resonance frequency. The dependence is shown using the normalized frequency.

  It can be seen that the insertion loss and the attenuation amount are deteriorated by the deviation of the convex-concave convex center Lc of the protective film from the center pc of the electrode finger of the comb-shaped electrode. Furthermore, it can be seen that the ripple generated near the normalized frequency of 1.02 is greatly generated in FIG. 19B, and the frequency difference between the antiresonance point and this ripple is narrow. When constructing a ladder-type SAW filter using this SAW device, if this ripple is large, the filter characteristics deteriorate, and if this ripple exists near the anti-resonance point, It appears as a big ripple.

Therefore, from the above results, the inventors set the shape of the SiO ₂ film to “L1 ≦ p1 and L2 ≧ p2 (where L≈p, p1 + p2 = p, L1 + L2 = L are satisfied)” In order to obtain good electrical characteristics in a device manufactured so as to satisfy the above relationship, the center of the width L1 of the convex portion 4a of the protective film 4 is Lc, and below and in the vicinity of the convex portion 4a of the protective film 4 When the center of the width p1 per one electrode finger 2 is defined as pc, Lc and pc are substantially on the same straight line when viewed from the upper surface of the substrate 1, that is, on the same line in plan view. It was found that this is preferable.

(Embodiment 5)
Hereinafter, a SAW device according to Embodiment 5 of the present invention will be described with reference to the drawings.

  The SAW device in the fifth embodiment is the same SAW device as the SAW device used in the third embodiment, although the number of electrodes and reflectors and the pitch p are different. Therefore, the structure and the creation method are the same as those shown in FIGS. 1A, 14 and 2, and the description thereof is omitted. The SAW device according to the fifth embodiment also satisfies the relationship “L1 ≦ p1 and L2 ≧ p2 (where L≈p, p1 + p2 = p, and L1 + L2 = L are satisfied)”.

  In the fifth embodiment, in order to show the relationship between the cut-out angle of the substrate 1 and the electrical characteristics of the SAW device on which the protective film having the shape shown in the third embodiment is formed, a comparison with different cut-off angles is performed. SAW devices were prepared using a total of five types of substrates of Examples 9, 10 and Examples 7, 8, and 9. Table 4 shows a list of cut-out angles of the LT substrate used for each SAW device.

  FIG. 20 shows the electrical characteristics of each SAW device. However, in FIG. 20, in order to consider the frequency deviation between the devices and to easily understand the difference in characteristics between the devices, the dependence using the normalized frequency normalized by the anti-resonance frequency of each SAW device is used. Is shown.

FIG. 20 shows that the amount of attenuation and steepness are greatly improved as the cut-out angle of the substrate 1 is increased from 34 ° to the higher angle side. In particular, in order to ensure an attenuation of −20 dB or more in the SAW device used in the fifth embodiment, it is sufficient that the substrate cutting angle is about 38 ° or more. Therefore, from the above results, the inventors have determined that the rotation angle D ° is LT as a substrate cut out from the Y plate rotated D ° around the X axis in the Z axis direction.
38 ° ≦ D °
It was confirmed that good temperature characteristics and electrical characteristics were obtained when the D ° YLT substrate was used.

(Embodiment 6)
Hereinafter, a SAW device according to a sixth embodiment of the present invention will be described with reference to the drawings.

  The SAW device in the sixth embodiment is the same SAW device as the SAW device used in the third embodiment although the number of electrodes and reflectors and the pitch p are different. Therefore, the structure and the creation method are the same as those shown in FIGS. 1A, 14 and 2, and the description thereof is omitted. The SAW device according to the sixth embodiment also satisfies the relationship “L1 ≦ p1 and L2 ≧ p2 (where L≈p, p1 + p2 = p, and L1 + L2 = L are satisfied)”. However, the normalized film thickness h / (2 × p) of the electrode was 5%.

In the sixth embodiment, in order to show the relationship between the film thickness of the SiO ₂ film, temperature characteristics, and electrical characteristics, the SAW devices having different SiO ₂ film thicknesses t are compared with three types as Examples 10, 11, and 12. As Example 11, a SAW device in which SiO ₂ was not formed was prepared. FIG. 21 shows the electrical characteristics of each device, and FIG. 22 shows the relationship between the electromechanical coupling coefficient (K2) calculated from the electrical characteristics shown in FIG. 21 and the SiO ₂ film thickness. However, with regard to the frequency dependence of the electrical characteristics in FIG. 21, the normalized frequency normalized with the resonance frequency of each SAW device in order to consider the frequency deviation between the devices and to easily understand the difference in characteristics between the devices. The dependence was shown using. Further, FIG. 23 shows temperature characteristics measured at the antiresonance frequency of each SAW device. Table 5 shows a list of normalized film thickness t / (2 × p), electromechanical coupling coefficient, and temperature characteristics of the SiO ₂ film of each device.

FIG. 23 shows that the temperature characteristic is improved as the thickness of the SiO ₂ film increases. In particular, when the normalized film thickness of the SiO ₂ film is about 0.13 or more, the temperature characteristic is −30 ppm / ° K or less, and further, the temperature coefficient is zero at about 30%. However, at the same time, FIG. 22 shows that the electromechanical coupling coefficient K2 decreases. As the electromechanical coupling coefficient K2 decreases, the steepness increases. At the same time, when a ladder-type SAW filter is configured using this SAW device, the bandwidth is narrowed. A coupling coefficient of about 6% or more is preferable in order to secure the filter bandwidth required in the currently popular mobile phone systems. A coupling coefficient of 6% is obtained from FIG. 22 when the normalized film thickness of SiO ₂ is about 20% or less. When the film thickness of the SiO ₂ film is about 35% or more, the coupling coefficient is 5% or less. It becomes very difficult to secure the band of the filter. Therefore, from the above results, the inventors use SiO ₂ as the protective film, and the thickness t of the protective film defined by the height from the substrate surface to the concave portion of the protective film is
13% ≦ t / (2 × p) ≦ 35%
It was confirmed that good temperature characteristics and electrical characteristics can be obtained when the above conditions are satisfied.

(Embodiment 7)
The electronic device according to Embodiment 7 of the present invention will be described below with reference to the drawings.

  In the present embodiment, a mobile phone will be described as an example of an electronic device.

  FIG. 24 (a) is a schematic view of a mobile phone according to Embodiment 7 of the present invention, and FIG. 24 (b) is an electric circuit diagram of the main part inside the same.

  As shown in the figure, the cellular phone of the seventh embodiment has an antenna 121 and an antenna duplexer 122 connected to the antenna 121. The antenna duplexer 122 includes a transmission SAW filter 122a, a reception SAW filter 122b, and a phase shift circuit 122c.

  The transmission SAW filter 122a and the reception SAW filter 122b in the seventh embodiment use the SAW device described in the third embodiment.

  FIG. 25A shows the electrical characteristics of the transmission SAW filter 122a measured at temperatures of -35 ° C., 25 ° C., and + 85 ° C.

For comparison, FIG. 25 (b) shows the electrical characteristics measured at temperatures of −35 ° C., 25 ° C., and + 85 ° C. for a SAW filter in which the SiO ₂ film having the same frequency band as that of the transmitting SAW filter 122a is not formed. Shown in In FIG. 25, the transmission band 131 and the reception band 132 in the cellular phone system taken as an example of the seventh embodiment are shown by hatching. In this cellular phone system, in the temperature range of −35 ° C. to + 85 ° C., in the case of a transmission filter, suppression of an insertion loss of −3.5 dB or less in the transmission band and −42 dB or more in the reception band is required.

When comparing (a) and (b) of FIG. 25, the filter having the characteristics of FIG. 25 (a) using the SAW device described in the third embodiment has a steep filter characteristic and a frequency due to temperature change. Since there is little drift, the insertion loss of -3.5 dB or less is achieved in the transmission band and -42 dB or more is achieved in the reception band in the temperature range of -30 ° C to + 85 ° C, which is the required performance of this cellular phone system. On the other hand, the filter without the SiO ₂ film having the characteristics shown in FIG. 25A cannot realize the steep characteristics, does not satisfy the requirements even at room temperature, and has a large frequency drift due to temperature. The characteristics cannot be satisfied in the range of 30 ° C to + 85 ° C.

  In contrast to the cellular phone using the SAW device described in Embodiment 1 for the transmitting SAW filter 122a and the receiving SAW filter 122b, the inventors have the same sensitivity in an environment of −30 ° C. to + 85 ° C. As a result, it was confirmed that there was little change in sensitivity with respect to temperature change.

  As described above, according to the present invention, the protective film is formed so as to cover the electrode formed on the substrate, and the shape and thickness of the protective film are set within a specific range, whereby the temperature characteristics and electrical characteristics are set. An electronic component having excellent characteristics can be obtained.

(A) Top view showing the configuration of the electronic component in Embodiment 1 of the present invention, (b) Cross-sectional view of the electronic component in Embodiment 1 of the present invention The figure explaining the manufacturing method of the electronic component in Embodiment 1 of this invention Overview of SAW filter in Embodiment 1 of the present invention (A) The figure which shows the electrical property of the SAW resonator in Embodiment 1 of this invention, (b) The figure which shows the electrical property of the SAW filter in Embodiment 1 of this invention (A) The figure which shows the electrical property of the SAW resonator in Embodiment 1 of this invention, (b) The figure which shows the electrical property of the SAW filter in Embodiment 1 of this invention (A) The figure which shows the electrical property of the SAW resonator in Embodiment 1 of this invention, (b) The figure which shows the electrical property of the SAW filter in Embodiment 1 of this invention The figure which showed the relationship between the normalization film thickness of the electrode in this Embodiment 1, and the ripple generation frequency The figure which showed the composition of the ladder type SAW filter Sectional drawing of the electronic component in Embodiment 2 of this invention The figure which showed the manufacturing method of the electronic component in Embodiment 2 of this invention (A) The figure which shows the electrical property of the SAW resonator in Embodiment 2 of this invention, (b) The figure which shows the electrical property of the SAW filter in Embodiment 2 of this invention (A) The figure which shows the electrical property of the SAW resonator in Embodiment 2 of this invention, (b) The figure which shows the electrical property of the SAW filter in Embodiment 2 of this invention (A) The figure which shows the electrical property of the SAW resonator in Embodiment 2 of this invention, (b) The figure which shows the electrical property of the SAW filter in Embodiment 2 of this invention Sectional drawing of the electronic component in Embodiment 3 of this invention Sectional drawing of the electronic component in Embodiment 3 of this invention The figure which shows the electrical property of the electronic component in Embodiment 3 of this invention The figure which shows the relationship between the structure of an electronic component in Embodiment 3 of this invention, and an electrical property (A) Sectional view of electronic component in Embodiment 4 of the present invention, (b) Diagram showing electrical characteristics of the electronic component in Embodiment 4 of the present invention (A) Sectional view of electronic component in Embodiment 4 of the present invention, (b) Diagram showing electrical characteristics of the electronic component in Embodiment 4 of the present invention The figure which shows the electrical property of the electronic component in Embodiment 5 of this invention The figure which shows the electrical property of the electronic component in Embodiment 6 of this invention The figure which shows the structure of the electronic component in Embodiment 6 of this invention, and the relationship of an electrical property The figure which shows the structure of the electronic component in Embodiment 6 of this invention, and the relationship of a temperature characteristic (A) Overview of electronic device according to the seventh embodiment of the present invention, (b) Electrical circuit diagram of essential parts inside the electronic device according to the seventh embodiment of the present invention (A) The figure which shows the electrical property of the electronic component in Embodiment 7 of this invention, (b) The figure which shows the electrical property of the electronic component in Embodiment 7 of this invention (A) The figure which shows the example of sectional drawing of the electronic component in embodiment of this invention, (b) The figure which shows the definition of the structure of the cross section of the electronic component in embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Comb electrode 2a Electrode finger 3 Reflector 4 Protective film 4a Convex part of protective film 4b Concave part of protective film 5 Pad 21 Substrate 22 Electrode film 23 Resist film 24 Protective film 25 Resist film 26 Pad 31 Substrate 32 SiO ₂ Membrane 33s SAW resonator in series arm 33p SAW resonator in parallel arm 34 Pad 94a Protective film convex portion 94b Protective film concave portion 121 Antenna 122 Antenna duplexer 122a Transmission SAW filter 122b Reception SAW filter 122c Phase shift line 131 Transmission band 132 Reception band 141 Top part of convex part of protective film 142 Curve that approximates the shape of the vicinity of the convex part of the protective film 143 Tangent line at the top part of the convex part of the curve that approximates the shape of the convex part of the protective film 144 A straight line connecting the bottom surfaces of the concave portions of the protective film 145 The shape near the top of the convex portion of the protective film Intersection of a straight line connecting the tangent line at the top of the convex part of the approximate curve and the bottom of the concave part of the protective film

Claims (12)

A substrate, a comb-shaped electrode provided on the upper surface of the substrate, and a protective film that covers the comb-shaped electrode and has a concavo-convex shape on the top surface. The surface of the substrate in contact with the protective film protrudes from the surface of the substrate. T is the height from the top of the substrate in contact with the protective film to the bottom of the concave portion of the protective film, and the bottom of the concave portion of the protective film is from the top of the convex portion of the protective film. The height (t-t1) of the protective film is t2, the pitch width per pitch of the concavo-convex shape of the protective film is L, the width of the concavo-convex convex portion per pitch of the concavo-convex shape of the protective film is L1, and the concave portion The width of the comb electrode is p2, the pitch width per pitch of the comb electrode is p, the width per electrode finger constituting the comb electrode is p1, the width between the electrode fingers is p2, the film of the comb electrode When the thickness is h,
t2 ≦ h
(However, the electronic components satisfy the relations of L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, L2 ≧ p2). In the comb electrode provided on the substrate, the relationship between the film thickness h of the comb electrode and the pitch width p per pitch of the comb electrode is:
0.05 ≦ h / (2 × p)
The electronic component according to claim 1, wherein A substrate, a comb-shaped electrode provided on the upper surface of the substrate, and a protective film that covers the comb-shaped electrode and has a concavo-convex shape on the top surface. The surface of the substrate in contact with the protective film protrudes from the surface of the substrate. T is the height from the top of the substrate in contact with the protective film to the bottom of the concave portion of the protective film, and the bottom of the concave portion of the protective film is from the top of the convex portion of the protective film. The height (t-t1) of the protective film is t2, the pitch width per pitch of the concavo-convex shape of the protective film is L, the width of the concavo-convex convex portion per pitch of the concavo-convex shape of the protective film is L1, the concave portion The width of the comb electrode is p2, the pitch width per pitch of the comb electrode is p, the width per electrode finger constituting the comb electrode is p1, the width between the electrode fingers is p2, the film of the comb electrode When the thickness is h,
h ≦ t2
(However, the electronic components satisfy the relations of L≈p, p1 + p2 = p, L1 + L2 = L, L1 ≦ p1, L2 ≧ p2). In the comb electrode provided on the substrate, the relationship between the film thickness h of the comb electrode and the pitch width p per pitch of the comb electrode is:
h / (2 × p) ≦ 0.05
The electronic component according to claim 3, wherein The ratio L1 / L between the pitch width L of the protective film per pitch and the width L1 of the concave and convex portions per pitch of the concave and convex shape of the protective film is η ′, and the pitch of the comb electrodes per pitch When the ratio p1 / p between the width p and the width p1 per electrode finger constituting the comb electrode is η, the relationship between η and η ′ is
η ′ / η ≦ 0.86
4. The electronic component according to claim 1, wherein L≈p, p1 + p2 = p, and L1 + L2 = L are satisfied. 5. The center of the width L1 of the convex part of the unevenness of the protective film per pitch is Lc, and the center of the width p1 of the electrode finger of the comb-shaped electrode located under the convex part of the protective film per pitch is pc. 4. The electronic component according to claim 1, wherein Lc and pc are on substantially the same straight line in plan view. When the substrate is a lithium tantalate substrate and the cutting angle of the lithium tantalate substrate is D ° as the rotation angle in the Z-axis direction around the X-axis,
38 ° ≦ D °
The electronic component according to claim 1, wherein the electronic component is cut from a Y plate. The comb-shaped electrode provided on the upper surface of the substrate and the protective film covering the comb-shaped electrode and having an uneven shape on the top surface are the height from the surface of the substrate in contact with the protective film to the bottom of the concave portion of the protective film. The relationship between t1 and the pitch width p per pitch of the comb electrode is
13% ≦ t1 / (2 × p) ≦ 35%
The electronic component according to any one of claims 1 and 3. The electronic component according to claim 1, wherein the protective film is silicon dioxide. A substrate, a comb-shaped electrode provided on the upper surface of the substrate, and a protective film provided so as to cover the comb-shaped electrode, and the top surface of the protective film is substantially flat, and is in contact with the protective film When the height from the surface of the substrate to the upper surface of the protective film is t, and the pitch width per pitch of the comb electrodes is p, the substrate is a lithium tantalate substrate, and the lithium tantalate When the cutting angle of the substrate is D ° as the rotation angle in the Z-axis direction around the X-axis,
38 ° ≦ D °
Cut out from the Y plate, and
13% ≦ t / (2 × p) ≦ 35%
Is an electronic component. In the comb electrode provided on the substrate, the relationship between the film thickness h of the comb electrode and the pitch width p per pitch of the comb electrode is:
0.05 ≦ h / (2 × p)
The electronic component according to claim 10, wherein An electronic apparatus having at least one antenna and an electric circuit electrically connected to the antenna, wherein the electric circuit includes a plurality of electronic components, and at least one of the plurality of electronic components is defined in claim 1. Thru / or 11 is an electronic device according to any one of the above.

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