JP2005210475A - Electronic component and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface acoustic wave device which is superior in yield and stability over time while made small-sized, and a manufacturing method therefor. <P>SOLUTION: Each of IDTs is formed on a piezoelectric substrate 10. Wiring patterns 3c, 3d, and 3e for electrically connecting the IDTs and the outside are formed on the piezoelectric substrate 10. On the wiring pattern 3d among the wiring patterns 3c, 3d, and 3e, an inter-layer resin layer 5 is formed to make the wiring pattern 3e with a different potential cross the wiring pattern 3d. A tapered part 5a is provided at an end of the inter-layer resin layer 5 along the lengthwise direction of the wiring pattern 3e formed on the inter-layer resin layer 5. The tapered part 5a has two slope parts 5b and 5c. The tapered part 5a has a taper angle of ≤65°. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electronic component such as a surface acoustic wave device that can be miniaturized and has excellent yield and stability over time, and a method for manufacturing the same.

  Conventionally, in a small communication device such as a mobile phone, a bandpass filter having a passband frequency in the range of several tens of MHz to several GHz is often used. An example of the bandpass filter is a surface acoustic wave device that can be miniaturized.

  As shown in FIG. 11, the surface acoustic wave device 500 includes a reflector (reflector) 510, a comb-like electrode portion 501, a comb-like electrode portion 502, and a comb-like shape along the surface wave propagation direction of the piezoelectric substrate 100. The filter element 504 is formed by arranging the electrode portion 503 and the reflector 511. Here, each of the comb-like electrode portions 501 to 503 is an electric signal-surface wave coupling converter (Inter Digital Transducer, hereinafter referred to as IDT) having interdigital electrodes that are interleaved with each other.

  On the piezoelectric substrate 100, input pads 520, output pads 521, and ground pads 522, 523, and 524 are formed, and the IDTs 501 to 503 and the pads 520 to 524 are electrically connected. Respective wiring patterns 525 to 530 are formed for electrical connection.

  Here, the IDTs 501 to 503, the reflectors 510 and 511, the pads 520 to 524, and the wiring patterns 525 to 530 are all conductive thin film patterns formed on the piezoelectric substrate 100.

  When an electric signal is applied to the input pad 520 of the surface acoustic wave device 500, the surface wave is excited by the IDT 501 and the IDT 503, and the surface is formed in a region including the IDT 501, IDT 502, and IDT 503 sandwiched between the reflector 510 and the reflector 511. A standing wave of waves is generated, and the IDT 502 converts the energy of the standing wave into an electric signal, whereby an output potential is generated at the output pad 521. Since the conversion characteristics when each IDT 501 to 503 converts an electrical signal and a surface wave has a frequency characteristic, the surface acoustic wave device 500 exhibits a bandpass characteristic.

  The surface acoustic wave device 500 shown in FIG. 11 has a longitudinal coupling in which the input IDTs 501 and 503 and the output IDT 502 are acoustically cascaded in an acoustic track sandwiched between the reflectors 510 and 511. This is a resonator type surface acoustic wave filter. However, as the surface acoustic wave device, besides the longitudinally coupled resonator type, there are various types such as a laterally coupled resonator type, a transversal type, a ladder type, and a lattice type.

  Both types of surface acoustic wave devices are formed by forming an IDT and a wiring pattern as a conductive thin film pattern on a piezoelectric substrate, and that the electrical signal-surface wave conversion of IDT has frequency characteristics. Band pass characteristics are obtained by using it.

Further, in order to reduce the size of the surface acoustic wave device, it is disclosed that an insulator such as SiO ₂ is sandwiched between at least a part of each wiring pattern so as to cross three-dimensionally (see Patent Documents 1 to 3). 5).

In sandwiched therebetween above conventional surface acoustic wave device with three-dimensionally cross between an insulator such as SiO _2, since it difficult to increase the thickness of the insulator such as SiO _2, is formed on a piezoelectric substrate each The filter characteristics are deteriorated due to the parasitic capacitance formed between the wiring patterns, particularly at the three-dimensional intersection.

  In particular, in a surface acoustic wave device using a large number of IDTs, the wiring patterns connecting the IDTs increase, the number of three-dimensional intersections increases, the parasitic capacitance increases, and the filter characteristics further deteriorate. .

  Therefore, the inventors of the present application considered that the insulator sandwiched between the three-dimensional intersections is an interlayer resin layer capable of increasing the thickness, but the bent portion of the wiring pattern straddling the interlayer resin layer (that is, the interlayer resin layer) The inconvenience that the wiring pattern is disconnected at the end portion in the width direction).

  In order to eliminate this inconvenience, it has been considered that the end in the width direction of the interlayer resin layer is tapered. As a prior art for forming such an interlayer resin layer in a tapered shape, Patent Document 6 using a photosensitive resin is cited. Patent Document 6 describes a mask for ultraviolet exposure for forming a via hole with a positive taper in a photosensitive resin film on a substrate. In the mask, a light-shielding pattern is drawn on a portion corresponding to the bottom of the via hole, and a light-shielding pattern of a thin line below the resolution limit of the photosensitive resin film is formed on a portion corresponding to the inclined portion of the via hole on the periphery, A mask pattern is used that is drawn close to the bottom of the via hole at a narrow interval, and gradually increases between the bottom and top edge of the via hole due to a wide interval near the top edge of the via hole. Yes.

As described in paragraph (0018) of Patent Document 6, when the light shielding pattern line is dense, the photosensitive resin film is not hardened, so that it is easily removed by development. Is formed.
JP-A-5-167387 (release date: July 2, 1993) JP-A-5-235684 (publication date: September 10, 1993) JP 7-30362 A (publication date: January 31, 1995) JP 2000-49567 A (publication date: February 18, 2000) JP 2000-138553 A (publication date: May 16, 2000) JP 5-190545 A (publication date: July 30, 1993)

  However, even when the end portion of the interlayer resin layer is tapered, there is a problem that the wiring pattern straddling the interlayer resin layer is broken. That is, as a result of investigating the cause, since the thermal expansion coefficient of the interlayer resin layer and the metal film of the wiring pattern and the piezoelectric substrate are different from each other, residual stress due to heat at the time of film formation occurs in the wiring pattern on the interlayer resin layer, It was found that the disconnection occurred due to the concentration of the stress on the convex portion moving from the flat portion (top portion) of the interlayer resin layer to the tapered portion.

  Normally, when an interlayer resin layer is formed by patterning a photosensitive resin using photolithography technology, exposure is performed in an exposure region with a small variation in exposure amount-film thickness dependency, and an exposure margin is increased in terms of film thickness variation. It is spreading. When the photosensitive resin is trapezoidal using photolithography technology, as described above, a method of forming a fine pattern below the resolution limit of the photosensitive resin film on the photomask portion corresponding to the edge portion of the interlayer resin film Also known is a method of partially changing the transmittance by changing the photomask material.

  Furthermore, when patterning of a photosensitive resin is performed using an exposure region having a small variation in exposure dose film thickness on a substrate having a high light transmittance and a large back surface roughness Ra, the exposure light is converted into a light transmittance. Is high, the light passes through the back surface of the substrate, and the back surface roughness Ra is large, so that it is reflected by the unevenness of the back surface of the substrate.

  The reflected light reaches the substrate surface and further to the photosensitive resin. The reflected light that reaches the photosensitive resin is exposed to the photosensitive resin region of the light-shielding portion of the photomask, causing a problem of pattern formation failure.

  However, if the photomask is used in a resin with a γ value of 1 or less and the exposure amount is limited, the exposure amount is limited, so that a pattern corresponding to a fine pattern portion below the resolution limit can be formed. It does not become trapezoidal.

  In addition, the method of changing the material of the photomask has a problem that the cost for manufacturing the photomask is high.

  In order to solve the above problems, an electronic component of the present invention includes a substrate, an electronic function unit and a pad formed on the substrate, a wiring pattern for connecting the electronic function unit and the pad, and the wiring. An electronic component having another wiring pattern having a different potential from the pattern and an interlayer insulating pattern for crossing the other wiring pattern on the wiring pattern, wherein the interlayer insulating pattern is the other wiring pattern It has a taper part formed in the edge part in the longitudinal direction of a wiring pattern, The taper part is provided with two or more inclined parts, and the angle of the taper part is 65 degrees or less.

  According to the above configuration, by providing two or more inclined portions in the tapered portion, setting the convex portions formed in the tapered portion to two or more, and setting the angle of the tapered portion to 65 degrees or less, In another wiring pattern formed on the interlayer insulating pattern, the stress applied to each part corresponding to each convex part can be reduced by dispersion and obtuse angle by making the convex parts plural. From this, the said structure can suppress generation | occurrence | production of the disconnection in another wiring pattern resulting from the said stress.

  Therefore, in the above configuration, another wiring pattern formed on the interlayer insulating pattern can be surely formed, so that another wiring pattern having a different potential is crossed on a part of the wiring patterns and the small size is obtained. It is possible to improve the yield and the stability over time while achieving the above.

  In the electronic component, the interlayer insulating pattern is preferably made of a photosensitive resin. In the electronic component, the photosensitive resin may be polyimide. According to the said structure, it becomes possible to make formation of a taper part easy because an interlayer insulation pattern consists of photosensitive resin.

  In the electronic component, the substrate preferably has a light transmittance of 50% to 80% and a back surface roughness Ra of 0.1 μm or more. According to the above configuration, it is possible to remove unnecessary waves from the back surface of the substrate and to ensure the formation of the tapered portion, which is particularly effective in a SAW filter as an electronic component.

In the electronic component, the electronic function unit may include a plurality of comb-shaped electrode portions on the substrate so as to have a filter function. In the electronic component, the substrate may be quartz, LiNbO ₃ , or LiTaO ₃ .

  In order to solve the above problems, an electronic component manufacturing method of the present invention is an electronic component in which an interlayer insulating pattern is formed on a substrate using a photosensitive resin, and a wiring pattern is formed so as to straddle the interlayer insulating pattern. In the manufacturing method, a photo-resist having a taper part including a tapered part light-transmitting part and a tapered part light-shielding part each having a size larger than the resolution limit and close to the resolution limit using a photosensitive resin having a γ value of 1 or less A photosensitive resin is exposed with the photomask using a mask, and a tapered portion is formed at the edge portion of the interlayer insulating pattern.

  According to the above method, the taper portion including the tapered portion light-transmitting portion and the tapered portion light-shielding portion each having a size larger than the resolution limit and close to the resolution limit using a photosensitive resin having a γ value of 1 or less. When the negative type is used for the photosensitive resin, the tapered portion can be reliably formed by using the photomask having the photomask.

  Therefore, in the above method, when the wiring pattern is formed so as to straddle the interlayer insulating pattern provided with the tapered portion at the edge portion, occurrence of disconnection in the wiring pattern can be prevented by the tapered portion.

  In addition, since the above method only requires that the photomask has a taper portion including a tapered portion light-transmitting portion and a tapered portion light-shielding portion each having a size larger than the resolution limit and close to the resolution limit. Therefore, the tapered portion can be reliably formed by the photomask while avoiding cost increase.

  In the said manufacturing method, when exposing photosensitive resin with the said photomask, it is preferable to restrict | limit an exposure amount to the exposure area | region different from the stable area | region with a small fluctuation | variation of exposure amount film thickness dependence.

  According to the above method, since the inclined portion of the taper portion formed in the interlayer insulating pattern can be more reliably formed by exposing with a limited exposure amount, disconnection occurs in the wiring pattern formed on the interlayer insulating pattern. Can be avoided more reliably.

  In the above manufacturing method, the photomask includes a tapered portion light-transmitting portion and a tapered portion light-shielding portion in a checkered pattern so that the tapered portion has two or more inclined portions and a taper angle of 65 ° or less. It is desirable.

  According to the above method, by forming the tapered portion light transmitting portion and the tapered portion light shielding portion in a checkered pattern, two or more inclined portions and a tapered portion having a taper angle of 65 ° or less can be more reliably formed.

  As described above, the electronic component of the present invention has another wiring pattern formed on the interlayer insulating pattern so as to intersect the wiring pattern, and the end of the interlayer insulating pattern in the longitudinal direction of the other wiring pattern. And the tapered portion includes two or more inclined portions, and the angle of the tapered portion is 65 degrees or less.

  Therefore, the above-described configuration can improve the yield and stability over time while crossing the two or more inclined portions and the angle of the tapered portion of 65 degrees or less to reduce the size. There is an effect.

  As described above, the method for manufacturing an electronic component of the present invention uses a photosensitive resin having a γ value of 1 or less, and has a tapered portion light-transmitting portion and a tapered portion each having a size larger than the resolution limit and close to the resolution limit. In this method, a photomask having a taper portion including a partial light shielding portion is used, and a photosensitive resin is exposed by the photomask to form a taper portion at an edge portion of the interlayer insulating pattern.

  Therefore, the above method uses a photosensitive resin having a γ value of 1 or less, and by using the photomask, the tapered portion can be reliably formed, and the occurrence of disconnection in the wiring pattern can be prevented by the tapered portion. Yield and stability over time can be improved.

  In addition, since the above method can form the photomask with the same effort as a conventional photomask, it is possible to avoid an increase in cost and to suppress an increase in cost while improving yield and stability over time. Play.

  Each embodiment of the present invention will be described with reference to FIGS. 1 to 10 as follows.

In the surface acoustic wave device as the electronic component of the present invention, as shown in FIG. 2, the IDTs (electronic function units) 1a to 1e that vibrate the surface acoustic waves on the surface of the piezoelectric substrate 10 are a set. It is formed along the propagation direction of the surface acoustic wave. In the present embodiment, an example in which a set of IDTs 1a to 1e is formed on the piezoelectric substrate 10 for the sake of explanation and drawing convenience is given, but a plurality of sets are usually formed as necessary. Yes. Moreover, as a formation density of each IDT, 4-8 pieces are mentioned in 1 mm < ² >.

The piezoelectric substrate 10 is a piezoelectric substrate such as LiTaO ₃ , LiNbO ₃ , or quartz, and has a light transmittance of 70% -80% or more at a wavelength of 300 nm or more and a back surface lap roughness Ra of 0.10 μm or more. Can be used. In this embodiment, a LiTaO ₃ substrate having a transmittance of 75% and a back surface wrap (Ra) roughness of 0.15 μm was used. The said back surface is a surface opposite to the formation surface of each IDT 1a-1e in the piezoelectric substrate 10. FIG.

  Further, on the piezoelectric substrate 10, the connection pads 2a and 2b for establishing electrical continuity with an external wiring board (not shown), the IDTs 1a to 1e, and the connection pads 2a and 2b are respectively provided. Wiring patterns 3a to 3d for routing to be connected are formed.

  The IDTs 1a to 1e, the connection pads 2a and 2b, and the wiring patterns 3a to 3d are formed by a multi-layer structure wiring mainly composed of aluminum (Al) and titanium (Ti) by a vacuum deposition method, a sputtering method, or a plating method. Has been. In the present embodiment, as the multilayer wiring, a Ti layer (thickness: 100 nm) is disposed on the piezoelectric substrate 10 side, and an Al layer (thickness: 1000 nm) is disposed on the Ti layer. Such multi-layered wiring can reduce wiring resistance.

  Further, a protective film (not shown) of a silicon oxide film or a nitride film is formed by sputtering so as to cover the IDTs 1a to 1e and the wiring patterns 3a to 3d that connect the IDTs 1a to 1e and the connection pads 2a and 2b. ) Is formed.

  In addition, each of the wiring patterns 3a to 3d is provided with intersections 4a to 4d in order to reduce the size. In such an intersection 4d (shown as a representative, the other intersections are also the same), which is one of the intersections 4a to 4d, as shown in FIGS. 1 and 3, the wiring pattern 3d is covered. An interlayer resin layer (interlayer insulating pattern) 5 is formed of polyimide having a thickness of 3 μm, for example.

  Further, the wiring pattern 3e that electrically connects the connection pad 2a and the wiring pattern 3c having a signal potential different from the ground potential extends over the interlayer resin layer 5 from above and sandwiches the interlayer resin layer 5 therebetween. The multilayer wiring is provided so as to intersect the pattern 3d.

  The interlayer resin layer 5 electrically insulates the wiring pattern 3d having the ground potential from the connection pad 2a and the wiring pattern 3c having the signal potential different from the ground potential. In addition, the routing distance of the wiring pattern 3e can be shortened and the size can be reduced.

In addition, since the interlayer resin layer 5 can have a lower dielectric constant (less than 4) and a thickness of 3 μm as compared with a conventional interlayer insulating film such as SiO ₂ , each wiring pattern 3d at the intersection can be formed. 3e can be reduced, and the filter characteristics in the obtained surface acoustic wave device, that is, the frequency characteristics in the pass band and the cutoff band can be improved.

  Then, as shown in FIG. 4, the interlayer resin layer 5 has an extension direction of the wiring pattern 3e straddling the interlayer resin layer 5 (the longitudinal direction of the wiring pattern 3e, in other words, the wiring pattern 3d included in the interlayer resin layer 5). At both end portions in the width direction), tapered portions 5a are formed which are directed toward the end portions and whose height decreases as a whole. Furthermore, the taper part 5a is formed with a plurality of, for example, two inclined parts 5b and 5c sequentially along the direction toward the end part. The top part 5e of the inclined part 5c on the end part side is lower than the height of the flat part (top part) 5f of the interlayer resin layer 5 corresponding to the top part of the inclined part 5b on the base part side.

  Such a surface acoustic wave device is used by being attached to a package or a wiring board of a communication device by flip chip bonding or wire bonding using the connection pads 2a and 2b.

  Next, the manufacturing method of the interlayer resin layer 5 provided with the taper part 5a used as the characteristic part in the manufacturing method of the surface acoustic wave device will be described.

  First, the IDTs 1a to 1e, the connection pads 2a and 2b, and the wiring patterns 3a to 3d are formed on the piezoelectric substrate 10 by the method described above. Subsequently, a photosensitive resin having a γ value of about 0.03 (in this embodiment, a resin made of a polyimide precursor) is spin-coated on the piezoelectric substrate 10 so as to have a thickness of about 5.5 μm, A photosensitive resin film is formed by baking for 100 seconds on a 115 ° C. hot plate. Here, the γ value is defined by the following equation when there is a remaining film rate curve with respect to the exposure amount as shown in FIG. The definition of the remaining film ratio is “film thickness after development / film thickness before development”.

γ = (D _g ⁰ −D _g ¹ ) ⁻¹
Here, D _g ⁰ represents the common logarithm of the exposure amount (log ₁₀ ) when the remaining film ratio is 1.0, and D _g ¹ represents the common logarithm of the exposure amount when the remaining film ratio is 0. . A remaining film ratio of 1.0 is a state in which the film thickness does not change even when development is performed. On the other hand, when the residual film ratio is 0, the polyimide is completely removed and removed (development is performed) when development is performed.

Thereafter, a photomask 7 shown in FIG. 7 is set on the piezoelectric substrate 10 on the photosensitive resin film, and ultraviolet rays are exposed on the photosensitive resin film through the photomask 7 with an exposure amount of 33 mJ / cm ^2. Projection irradiation. The exposure amount is an exposure amount at which the residual film ratio becomes 80%, and is a region having a large dependency on the exposure amount / line width. The photosensitive polyimide used in the present embodiment is a negative photosensitive resin. Therefore, the portion where the photosensitive resin film made of photosensitive polyimide is not exposed is developed, and the film does not exist during the rinsing process.

  The photomask 7 is made of glass, and a substantially square light-transmitting portion 7a corresponding to the interlayer insulating film 5 portion is disposed at the center in the longitudinal direction. Further, at both ends of the light transmitting portion 7a (positions corresponding to the respective tapered portions 5a), taper portion light transmitting portions 7b having 5 μm square and taper portion light shielding portions 7c having 5 μm square are alternately adjacent to each other. Are arranged in a lattice pattern (checkered pattern). Thus, the taper portion patterns 7d for forming the respective taper portions 5a at the end (edge) portion of the interlayer resin layer 5 are formed.

  The tapered portion pattern 7d includes the tapered portion light transmitting portion 7b and the tapered portion light shielding portion 7c, and the pattern rows 7e and 7f along the width direction of the light transmitting portion 7a are inclined with respect to the tapered portion 5a. According to the number of the parts 5c and 5b, it is preferable that they are formed adjacent to each other along the longitudinal direction of the light transmitting part 7a.

  Furthermore, the pattern row 7e on the end side is set so that the ratio of the tapered portion light transmitting portion 7b to the total of the tapered portion light transmitting portion 7b and the tapered portion light shielding portion 7c is larger than that of the pattern row 7f. It is desirable. By such setting, the inclined portions 5c and 5b can be formed so as to become lower toward the end portion.

  Next, the photosensitive resin film exposed through the photomask 7 is developed with cyclopentanone and rinsed with 1-methoxy-2-acetoxypropane. Although the piezoelectric substrate 10 transmits the exposure light, the amount of exposure is limited. Therefore, the influence of the reflected light from the back surface of the piezoelectric substrate 10 is small, resulting in a pattern defect in which the light shielding portion of the photomask 7 is exposed. I will not let you.

  Subsequently, the developed and rinsed piezoelectric substrate 10 is spin-dried. Thereafter, curing is performed at 305 ° C. for 1 hour in a nitrogen atmosphere having an oxygen concentration of 20 ppm or less, and the remaining photosensitive resin film is thermally polymerized to obtain polyimide. As a result, the photosensitive resin film is cured, and an interlayer resin layer 5 having a thickness of about 3.0 μm is formed with each tapered portion 5a. Since the interlayer resin layer 5 limits the exposure amount, the cross-sectional shape of the edge portion is not a rectangular shape, but can be a tapered portion 5a having a slope.

  Further, since the photomask 7 is used and the exposure is performed with an exposure amount such that the remaining film ratio is 80%, the edge region of the interlayer resin layer 5 is 2 as shown in FIG. A continuous pattern having two inclined portions 5b and 5c is formed. As shown in FIG. 5, the top (convex portion) 5 e formed by the inclined portion 5 c outside (end portion side) the edge region of the interlayer resin layer 5 has a height of 1.5 μm. On the other hand, the recess 5d formed by the inner (base side) inclined portion 5b has a height of 1.0 μm. The angles of the inclined surfaces of the inclined portions 5c and 5b are 37 ° and 38 ° from the outside (the angles are positive on the interlayer resin layer 5 side from the surface of the piezoelectric substrate 10).

  Thereafter, different metals were stacked on the interlayer resin layer 5 so as to reduce the wiring resistance in the routed wiring pattern by the vacuum deposition method, the sputtering method or the plating method across the interlayer resin layer 5. A wiring pattern 3e which is a multilayer structure wiring is formed.

  As a result, the wiring pattern 3e can be formed on the interlayer resin layer 5 while preventing the disconnection. For example, a surface acoustic wave device in which the wiring pattern 3c and the connection pad 2a are securely connected by the wiring pattern 3e is obtained. be able to.

  Next, a surface acoustic wave device of a comparative example will be described. In the comparative example, as shown in the cross-sectional photograph of the wiring pattern 13 in FIG. 8, a multilayer wiring pattern 13 is formed on the interlayer resin layer 15 without forming a tapered portion in the interlayer resin layer 15 on the piezoelectric substrate 10. Has been. As can be seen from FIG. 8, in the wiring pattern 13, the disconnection 13 a occurs in the edge region of the interlayer resin layer 15.

  On the other hand, in the surface acoustic wave device of the present invention, as shown in FIG. 9, in the wiring pattern 3e formed on the interlayer resin layer 5, the inclination of the interlayer resin layer 5 end is relaxed by the formation of the tapered portion 5a. Therefore, it turns out that generation | occurrence | production of a disconnection is prevented.

  Next, it is shown that a preferable effect is obtained when the inclination angle of the tapered portion 5a is 65 degrees or less. First, when the film thickness of the interlayer resin layer 5 is changed using the same photomask 7 used in the present embodiment, a taper occurs when the interlayer resin layer 5 is thick as shown in FIG. When the taper angle indicating the overall inclination of the portion 5a increases and the taper angle exceeds 65 °, for example, reaches 75 °, as shown in FIG. 10C, the flat portion of the interlayer resin layer 5 It can be seen that disconnection of the wiring pattern formed on the interlayer resin layer 5 occurs in the convex portion that moves to the taper portion 5a. As shown in FIGS. 10A and 10B, it can be seen that the wiring pattern is not disconnected when the taper angle is 65 degrees or less.

  The present invention is not limited to the above embodiment, and the edge region of the interlayer resin layer 5 is subject to various applications and modifications within the scope of the invention with respect to the number of inclinations and inclination angles. Is possible.

  In the above embodiment, photosensitive polyimide is used for the interlayer resin layer 5, but other photosensitive resins are also possible. Besides polyimide, photosensitive epoxy resin, benzocyclobutene resin, bismaleimide triazine resin, An acrylic resin and a cyclic olefin resin can be used. As the photosensitive resin, a negative type using an organic solvent as a developer is preferable. A positive type photosensitive resin is not preferable because an alkali is used for the developer and the aluminum electrode dissolves. Furthermore, it is possible even when a resin other than the photosensitive resin is used for the interlayer resin layer 5.

  As described above, the surface acoustic wave device and the manufacturing method thereof according to the present invention can avoid the influence of reflected light from the back surface of the piezoelectric substrate 10 by limiting the appropriate exposure amount at the time of patterning the photosensitive resin film. As a result, the interlayer resin layer 5 can be formed without causing a pattern defect in which the photosensitive resin film corresponding to the light shielding portion of the photomask 7 is exposed.

  Further, a photomask 7 is formed so that a continuous pattern having at least two inclined portions 5b and 5c can be formed on the tapered portion 5a of the interlayer resin layer 5 and a pattern having an angle of 65 ° or less can be formed. A multilayer wiring formed by stacking another wiring pattern on the routing wiring pattern for reducing the wiring resistance in the routing wiring pattern by using the wiring pattern is formed on the interlayer resin layer 5 without disconnection. Can do.

  In the above-described embodiment, an example in which an Al / Ti multilayer structure wiring is used as the wiring pattern has been described. However, other metals may be used, for example, Cu, Au, Ag, Al, Ni, A metal material containing at least one selected from the group consisting of Ti, Cr, NiCr, Nv, V, Ta, W, Pt and Mo, or a multilayered material thereof may be used.

  Moreover, in the said embodiment, although the 5 micrometers square (□) thing was used for the taper part light transmission part 7b and the taper part light-shielding part 7c of the photomask 7, it is not limited to 5 micrometers. The sizes of the tapered portion light-transmitting portion 7b and the tapered portion light-shielding portion 7c vary depending on the resin used and the resolution limit determined by the photolithography conditions, and are larger than the resolution limit and different from the resolution limit. As long as it has a size closer to the resolution limit than the translucent portion 7a.

  Furthermore, in the manufacturing method described in the above embodiment, the example in which the tapered portion 5a is formed by using the photomask 7 is given. However, if only the shape of the tapered portion 5a is obtained, it is described in the background art column. It is also possible to use the described tapered method. However, the surface acoustic wave device can be manufactured at a lower cost by using the photomask 7.

  Next, functions and effects of the taper portion pattern 7d of the photomask 7 will be described. The purpose of the taper portion pattern 7d is to obtain a taper portion 5a having a small remaining film ratio, that is, an inclined surface as a whole, as compared with the large rectangular translucent portion 7a.

  The estimation mechanism by which the tapered portion 5a having the two inclined portions 5b and 5c is obtained with the photomask 7 is as follows.

  The size of the tapered light-shielding part 7c and the tapered light-transmitting part 7b is large unlike the resolution limit, such as 5 μm, but by setting a value close to the resolution limit, An inclined portion 5b having the first inclination is obtained between the portion 5a and the pattern row 7f in which the 5 μm square tapered portion light-shielding portion 7c and the 5 μm square tapered portion light-transmitting portions 7b are alternately arranged in a grid pattern.

  Further, by setting the same dimensions, an inclined portion 5c that is a second inclination is obtained between the lattice pattern pattern row 7e and a frame portion that is a large light-shielding portion around it. Between each pattern row 7f and 7e, the recessed part 5d located between two each inclination part 5b and 5c is obtained.

  Furthermore, depending on the resin used and the photolithographic conditions, the concave portion 5d may not be formed, and an inclined portion having a gentle angle may be formed. Even in this case, similarly to the case where the concave portion 5d is formed, the stress is dispersed and the occurrence of disconnection or cracking is prevented.

  The present invention can reduce the size by crossing the wiring patterns, and can improve the connection stability at the crossing portion. Therefore, the electronic component having the electronic function portion and the wiring pattern formed on the substrate is required to be downsized. And can be suitably used in the field of manufacturing methods thereof.

It is principal part sectional drawing of the surface acoustic wave apparatus of this invention. It is a schematic block diagram of the said surface acoustic wave apparatus. It is a schematic plan view of the surface acoustic wave device. It is principal part sectional drawing which shows the taper part in the interlayer resin layer of the said surface acoustic wave apparatus. It is principal part sectional drawing which shows the taper part and its inclination part in the interlayer resin layer of the said surface acoustic wave apparatus including those angles. It is a graph which shows the remaining film ratio with respect to the exposure amount used for the manufacturing method of the said surface acoustic wave apparatus. It is a top view of the photomask used for the manufacturing method of the said surface acoustic wave apparatus. It is principal part sectional drawing by the microscope picture in the surface acoustic wave apparatus of a comparative example. It is principal part sectional drawing by the microscope picture in the surface acoustic wave apparatus of this invention. The relationship between the taper angle of the taper portion and the wiring pattern formed on the interlayer resin layer is shown. (A) is a wiring pattern that is not broken when the taper angle is 54 ° (deg). (B) shows a good wiring pattern when the taper angle is 64 ° and not broken, and (c) shows a bad wiring pattern when the taper angle is 76 ° and broken. (D) shows a graph of the above relationship. It is a schematic block diagram of the conventional surface acoustic wave apparatus.

Explanation of symbols

2a, 2b: Connection pads (pads)
3c, 3d, 3e: wiring pattern 5: interlayer resin layer (interlayer insulation pattern)
5a: Tapered portion 5b, 5c: Inclined portion 10: Piezoelectric substrate (substrate)

Claims (9)

A substrate,
An electronic function unit and a pad formed on the substrate;
A wiring pattern for connecting the electronic function unit and the pad;
Another wiring pattern having a different potential from the wiring pattern;
An electronic component having an interlayer insulating pattern for crossing the another wiring pattern on the wiring pattern,
The interlayer insulating pattern has a tapered portion formed at an end in the longitudinal direction of the another wiring pattern,
The tapered portion includes two or more inclined portions;
An angle of the taper portion is 65 degrees or less.   The electronic component according to claim 1, wherein the interlayer insulating pattern is made of a photosensitive resin.   The electronic component according to claim 2, wherein the photosensitive resin is polyimide.   4. The electronic component according to claim 2, wherein the substrate has a light transmittance of 50% to 80% and a back surface roughness Ra of 0.1 [mu] m or more.   5. The electronic component according to claim 1, wherein the electronic function part includes a plurality of comb-like electrode parts on the substrate so as to have a filter function. 6. The electronic component according to claim 5, wherein the substrate is made of quartz, LiNbO ₃ , or LiTaO ₃ . In the manufacturing method of the electronic component in any one of Claims 1 thru | or 6,
Using a photosensitive resin having a γ value of 1 or less,
Using a photomask having a taper portion translucent portion and a taper portion light shielding portion each having a size larger than the resolution limit and close to the resolution limit,
A method of manufacturing an electronic component, comprising: exposing a photosensitive resin with the photomask to form a tapered portion at an edge portion of an interlayer insulating pattern.   8. The method of manufacturing an electronic component according to claim 7, wherein when the photosensitive resin is exposed by the photomask, the exposure amount is limited to an exposure region different from a stable region having a small variation in exposure amount film thickness dependency. The photomask includes a tapered portion light-transmitting portion and a tapered portion light-shielding portion in a checkered pattern so that the tapered portion has two or more inclined portions and a taper angle of 65 ° or less. The manufacturing method of the electronic component of Claim 7 or 8.

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