JP2010245704A - Substrate for surface acoustic wave device and surface acoustic wave device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface acoustic wave device excellent in airtightness. <P>SOLUTION: The surface acoustic wave device 100 includes: a mounting substrate 102; a surface acoustic wave element 150 arranged oppositely over the top surface of the mounting substrate 102; pads 118 provided on the top surface of the mounting substrate 102; a solder layer 122 covering the pads 118; and a dam material 134 provided on the top surface of the mounting substrate 102 and surrounding the pads 118. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a surface acoustic wave element substrate and a surface acoustic wave device.

In the surface acoustic wave device, as a technique for mounting the surface acoustic wave element, a technique of sealing in a state where a space is secured on a functional surface of the surface acoustic wave element with a photosensitive resin is known. For example, Patent Document 1 describes a mounting structure of a surface acoustic wave element (SAW element). According to the same document, this mounting structure has a mounting board having a connection pad, and a connection pad provided on the functional surface in a state where the functional surface is opposed to the mounting board by Au bumps on the connection pad. A SAW element connected and mounted on the mounting board, and a photosensitive resin filled between the SAW element and the mounting board in the peripheral portion of the SAW element are provided, and the functional surface of the SAW element is provided by the photosensitive resin. It is described that the structure is sealed in a state where a space facing the configured vibration propagation portion is secured.
This photosensitive resin cannot be bonded to the SAW element. Therefore, in the mounting structure described in Patent Document 1, the photosensitive resin and the SAW element are bonded via a protective layer (SiO ₂ film).

Japanese Patent Laid-Open No. 11-67830

The SAW element mounting substrate described in Patent Document 1 has room for improvement in terms of airtightness.
When a photosensitive resin is provided between the SAW element and the mounting substrate without using a protective layer (SiO ₂ film), the photosensitive resin cannot be bonded to the SAW element as described above. It becomes difficult to maintain the sex.

  An object of the present invention is to provide a surface acoustic wave device having excellent airtightness.

According to the present invention,
A mounting board;
A pad provided on the upper surface of the mounting substrate;
A solder layer covering the pad;
A dam material which is provided on the upper surface of the mounting substrate and surrounds the pad in a plan view of the mounting substrate;
A surface acoustic wave device substrate is provided.

According to the present invention,
A mounting board;
A surface acoustic wave element disposed opposite to the upper surface of the mounting substrate;
A pad provided on the upper surface of the mounting substrate;
A solder layer covering the pad;
A dam material provided on the upper surface of the mounting substrate and surrounding the pad in a plan view of the mounting substrate;
The surface acoustic wave element substrate is composed of the mounting substrate, the pad, the solder layer, and the dam material,
The dam material is provided between the mounting substrate and the surface acoustic wave element,
There is provided a surface acoustic wave device in which the pad and the solder layer connect the mounting substrate and the surface acoustic wave element.

  The dam material has adhesiveness to the surface acoustic wave element. For this reason, the surface acoustic wave element and the mounting substrate can be bonded via the dam material. Thereby, the airtightness inside the surface acoustic wave apparatus which consists of a mounting substrate, a surface acoustic wave element, and a dam material can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the surface acoustic wave apparatus excellent in airtightness is provided.

1 is a cross-sectional view schematically showing a surface acoustic wave device according to an embodiment of the present invention. 1 is a cross-sectional view schematically showing a surface acoustic wave element substrate according to an embodiment of the present invention. It is process sectional drawing which shows the procedure which manufactures the surface acoustic wave apparatus which concerns on embodiment of this invention. It is process sectional drawing which shows the procedure which manufactures the surface acoustic wave apparatus which concerns on embodiment of this invention. It is process sectional drawing which shows the procedure which manufactures the surface acoustic wave apparatus which concerns on embodiment of this invention. It is process sectional drawing which shows the procedure which manufactures the surface acoustic wave apparatus which concerns on embodiment of this invention. It is a figure which shows the modification of the surface acoustic wave apparatus of this invention. It is sectional drawing which showed typically the modification of the board | substrate for surface acoustic wave elements which concerns on embodiment of this invention. FIG. 9 is a process cross-sectional view illustrating a procedure for manufacturing the surface acoustic wave element substrate illustrated in FIG. 8. FIG. 9 is a process cross-sectional view illustrating a procedure for manufacturing the surface acoustic wave element substrate illustrated in FIG. 8. FIG. 9 is a process cross-sectional view illustrating a procedure for manufacturing the surface acoustic wave element substrate illustrated in FIG. 8.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

A surface acoustic wave device 100 according to the present embodiment will be described with reference to FIG.
The surface acoustic wave device 100 according to the present embodiment includes a mounting substrate 102, a surface acoustic wave element 150 disposed opposite to the upper surface of the mounting substrate 102, a pad 118 provided on the upper surface of the mounting substrate 102, and a pad 118. A solder layer 122 to be covered, and a dam material 134 provided on the upper surface of the mounting substrate 102 and surrounding the pad 118 in a plan view of the mounting substrate 102 are provided.

  The frame-shaped dam material 134 is provided between the mounting substrate 102 and the surface acoustic wave element 150. Further, the pad 118 and the solder layer 122 connect the mounting substrate 102 and the surface acoustic wave element 150. The surface acoustic wave device 100 includes a filled via 114, a barrier film (first metal layer 120), a first circuit 126, a photosensitive insulating resin layer 128, a Ni film 130, an Au film 132, a pad 144, and the like shown in FIG. A mold resin 160 is further provided.

Next, a method for manufacturing the surface acoustic wave device 100 will be described with reference to FIGS.
FIG. 2 is a schematic view showing a part of a substrate 200 for a surface acoustic wave element having a filled via structure according to the present embodiment. 3 to 6 are process cross-sectional views illustrating a manufacturing procedure of the surface acoustic wave device 100 according to the present embodiment. In each step, a part of the entire mounting substrate 102 is shown.
The outline of the manufacturing process of the surface acoustic wave device 100 is as follows. First, a plurality of frame-shaped dam materials 134 are formed on the mounting substrate 102 to manufacture a sheet of the surface acoustic wave element substrate 200. The surface acoustic wave element 150 is mounted on each dam material 134 on the sheet and separated into individual pieces to obtain a plurality of surface acoustic wave devices 100 at a time.

As a premise of the manufacturing process of the surface acoustic wave device 100, a manufacturing process of the surface acoustic wave element substrate 200 will be described below.
First, a mounting substrate 102 is prepared, and a first metal foil 104 (first copper foil) and a second metal foil 106 (second copper foil) are formed on both surfaces of the mounting substrate 102 (FIG. 3). (a)). At this time, a through hole (not shown) for alignment marks may be formed at the end of the mounting substrate 102. Subsequently, an opening is formed in the second metal foil 106. A blind via 110 (FIG. 3B) is formed on the mounting substrate 102 (FIG. 3A) in the opening by using a UV laser or the like. Further, a desmear process is performed to remove smear (FIG. 3B) generated during via formation. For this desmear treatment, a wet method using a permanganic acid solution or a dry method using plasma is often used. Then, after the electroless plating 111 (FIG. 3B), filled via plating 112 (copper plating) (FIG. 3C) is performed. The filled via plating 112 at this time may use electroless plating or may fill the blind via 110 using another conductive material.

Next, as shown in FIG. 4A, the upper surface of the mounting substrate 102 is exposed by a photolithography method to form a pad 118 (circuit) on the filled via 114. Further, a solder layer 122 is formed on the pad 118 using a plating method, a paste printing method, or the like. In this case, the solder layer 122 is a solder metal made of at least one metal selected from tin, lead, silver, copper, zinc, nickel, bismuth, antimony, indium, and gold. For example, there are tin, tin-lead, tin-silver, tin-zinc, tin-bismuth, tin-antimony, tin-silver-bismuth, tin-copper, etc. The composition is not limited, and an optimal composition may be selected. The thickness of the solder layer 122 is not particularly limited, but is preferably 3 to 30 μm, more preferably 10 to 20 μm (hereinafter, “to” includes an upper limit value and a lower limit value unless otherwise specified). Represents).
At this time, marks (not shown) for determining the dicing position are formed on the outer peripheral portion of the mounting substrate 102. As this mark, for example, a conductor is used. As this conductor, copper, tin, silver, gold, nickel and alloys thereof are used.

  Further, at the time of soldering, the first metal layer 120 (barrier layer) such as nickel is used as a base layer for the purpose of preventing connection deterioration due to metal diffusion between the solder layer 122 and the pad 118 (copper foil layer). It may be formed between 122 and the pad 118. At this time, the film thickness of the 1st metal layer 120 shall be 1-6 micrometers, for example.

  Subsequently, a protective sheet 124 that protects the bumps is attached so as to cover the mounting substrate 102 and the solder layer 122 (bumps) (FIG. 4B). Further, a desired first circuit 126 is formed by, for example, etching the second metal film 116 on the lower surface of the mounting substrate 102 (FIG. 4C).

  Subsequently, a photosensitive resin is formed on the lower surface of the mounting substrate 102, and subjected to solder resist printing, exposure, and development processing, thereby forming a photosensitive insulating resin layer 128 (FIG. 5A). Further, an Ni film 130 and an Au film 132 are formed in this order on the first circuit 126 by using an electroless plating method (FIG. 5A). Thereafter, the protective sheet 124 is peeled off (FIG. 5B).

Next, an electron beam curable sheet-like adhesive film (not shown) is attached so as to cover the lower surface of the mounting substrate 102 (the surface on which the solder layer 122 is provided). Subsequently, using a photomask, the sheet-like adhesive film is selectively irradiated with an electron beam (for example, ultraviolet rays). Thereby, the part irradiated with light among the sheet-like adhesive films is photocured. When the sheet-like adhesive film after exposure is developed with a developer (for example, an alkaline aqueous solution, an organic solvent, etc.), the light-irradiated portion remains without being dissolved in the developer, thereby forming a frame-shaped dam material 134. Is done. At this time, a plurality of frame-shaped dam materials 134 are formed in regions other than the respective pads 118 on the mounting substrate 102 so as to surround the pads 118 in a plan view of the mounting substrate 102 (FIG. 5C). At this time, the position of the outer peripheral surface of each dam material 134 is determined according to the mark.
As described above, the surface acoustic wave element substrate 200 of the present embodiment (FIGS. 2 and 5C) can be obtained.

Next, a manufacturing process of the surface acoustic wave device 100 using the surface acoustic wave element substrate 200 will be described.
First, the surface acoustic wave element substrate 200 obtained in the above-described process is prepared, and the surface acoustic wave element 150 is placed on each dam member 134 (FIG. 6A). The mounting substrate 102 and the surface acoustic wave element 150 are heated and pressed by the dam material 134 and temporarily bonded (FIG. 6A). The heating and pressing conditions at this time are 140 ° C. to 260 ° C. and 20 kPa to 30 kPa.
At this time, the surface acoustic wave element 150 is mounted on the mounting substrate 102 via the solder bump (solder layer 122). Further, when viewed from the direction perpendicular to the mounting substrate 102, the outer peripheral portion of the dam material 134 protrudes from the outer peripheral portion of the surface acoustic wave element 150.

  A wiring (pad 144) is patterned on the lower surface of the surface acoustic wave element 150. Subsequently, the mounting substrate 102 and the surface acoustic wave element 150 are subjected to reflow processing, whereby the pad 144 and the pad 118 of the mounting substrate 102 are subjected to reflow processing. Are electrically connected through the solder layer 122 (FIG. 6B). The reflow treatment conditions at this time are 200 ° C. to 260 ° C. At this time, the mounting substrate 102 and the surface acoustic wave element 150 are sufficiently bonded via the dam material 134.

  Next, a mold resin 160 (sealing material) is formed on the surface acoustic wave element 150 (FIG. 6C). At this time, the molding resin 160 is transfer molded using a mold.

  Thereafter, a cutting is made in a broken line portion in FIG. 6C by a dicing saw from the surface acoustic wave element 150 side, and the mounting substrate 102 and the surface acoustic wave element 150 are divided according to the surface acoustic wave device 100 unit ( FIG. 6 (c)). At this time, the mold resin 160 is formed only on the surface acoustic wave element 150. That is, by controlling the dicing position, dicing can be performed at the side surface portion of the dam material 134. The position of the side surface of the dam material 134 can be grasped by the above-mentioned mark. Thereby, the side surface of the dam material 134 is exposed without being covered with the mold resin 160. The mold resin 160 is formed only on the upper surface of the surface acoustic wave element 150. Note that the formation of the mold resin 160 may be omitted. A plurality of filled vias 114 and pads 118 in each surface acoustic wave element substrate 200 may be provided according to the number of pads 144 of the surface acoustic wave element 150.

  Through the above steps, the surface acoustic wave device 100 (FIG. 1) in which the side surface of the dam material 134 is exposed is obtained.

  Next, the dam material 134 according to the present embodiment will be described in detail.

  The dam material 134 is formed by curing an electron beam curable resin composition for a dam material. Here, the electron beam is a concept including radiation having a wavelength of 150 nm to 700 nm, and includes, for example, near ultraviolet rays and ultraviolet rays.

  This resin composition for dam materials preferably contains a thermosetting resin. Thereby, the dam material 134 has adhesiveness to the surface acoustic wave element 150. Further, even after the dam material 134 is exposed, developed, and patterned, it can have adhesiveness. That is, the mounting substrate 102 and the surface acoustic wave element 150 are bonded by thermocompression bonding after arranging the adhesive component at a predetermined position by bonding the dam material 134 and performing exposure, development, and patterning. Can do.

  Examples of thermosetting resins include phenol novolac resins, cresol novolac resins, novolac phenol resins such as bisphenol A novolac resins, phenol resins such as resol phenol resins, bisphenol epoxy resins such as bisphenol A epoxy resins and bisphenol F epoxy resins. , Novolac epoxy resins, cresol novolac epoxy resins, novolac epoxy resins, biphenyl type epoxy resins, stilbene type epoxy resins, triphenolmethane type epoxy resins, alkyl-modified triphenolmethane type epoxy resins, triazine nucleus-containing epoxy resins, dicyclo Epoxy resins such as pentadiene-modified phenolic epoxy resins, urea (urea) resins, resins having a triazine ring such as melamine resins, unsaturated poly Ester resins, bismaleimide resins, polyurethane resins, diallyl phthalate resins, silicone resins, resins having a benzoxazine ring, cyanate ester resins, epoxy-modified siloxane, etc. These may be used singly or in admixture. Among these, an epoxy resin is particularly preferable. Thereby, heat resistance and adhesiveness can be improved more.

  Moreover, it is preferable to use together an epoxy resin (especially bisphenol type epoxy resin) solid at room temperature and an epoxy resin (especially silicone modified epoxy resin) liquid at room temperature as an epoxy resin. Thereby, it can be set as the dam material 134 which is excellent in both flexibility and resolution, maintaining heat resistance.

  Although content of a thermosetting resin is not specifically limited, 10 to 40 weight% of the whole resin composition for dam materials which comprises the dam material 134 is preferable, and 15 to 35 weight% is especially preferable. If the content is less than the lower limit, the effect of improving the heat resistance may be reduced, and if the content exceeds the upper limit, the effect of improving the toughness of the dam material 134 may be reduced.

  The thermosetting resin can further include a phenol novolac resin. The developability can be improved by adding a phenol novolac resin. Moreover, by including both an epoxy resin and a phenol novolac resin, the thermosetting property of the epoxy resin can be improved, and the strength of the dam material 134 can be further improved.

  Moreover, the resin composition for dam materials contains alkali-soluble resin, photopolymerizable resin, and 9 weight% or less of inorganic fillers. The photopolymerizable resin contains an acrylic polyfunctional monomer.

  Examples of the alkali-soluble resin include (meth) acryl-modified novolak resin such as (meth) acryl-modified bis A novolak resin, acrylic resin, copolymer of styrene and acrylic acid, polymer of hydroxystyrene, polyvinylphenol, poly Examples include α-methylvinylphenol, among which acrylic-modified novolak resins are preferable, and (meth) acryl-modified novolak resins are particularly preferable. Thereby, not only an organic solvent but an alkaline aqueous solution with a small environmental load can be applied to the developer, and heat resistance can be maintained.

  Although content of alkali-soluble resin is not specifically limited, 50 to 95 weight% of the whole resin composition for dam materials which comprises the dam material 134 is preferable. If the content is less than the lower limit, the effect of improving the compatibility may be reduced, and if the content exceeds the upper limit, the developability or resolution may be reduced.

  An acrylic polyfunctional monomer is used as the photopolymerizable resin. A polyfunctional monomer refers to a monomer having three or more functions, and in the present embodiment, a trifunctional or tetrafunctional acrylate compound can be suitably used. A bifunctional or lower monomer is not preferable because the strength of the dam material 134 becomes weak and the shape of the surface acoustic wave device 100 cannot be maintained.

  Specifically, as an acrylic polyfunctional monomer, trifunctional (meth) acrylates such as trimethylolpropane tri (meth) acrylate and pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and ditrimethylolpropane There are tetrafunctional (meth) acrylates such as tetra (meth) acrylate and hexafunctional (meth) acrylates such as dipentaerythritol hexa (meth) acrylate. Among these, trifunctional (meth) acrylate or tetrafunctional (meth) acrylate is preferable. By using trifunctional (meth) acrylate or tetrafunctional (meth) acrylate, the strength of the dam material 134 after exposure can be increased, and the shape retention property when the mounting substrate 102 and the surface acoustic wave element 150 are bonded together can be improved. Can be improved.

  Although content of an acryl-type polyfunctional monomer is not specifically limited, 1 to 50 weight% of the whole resin composition for dam materials which comprises the dam material 134 is preferable, and 5 to 25 weight% is especially preferable. If it is less than the lower limit value, the strength of the dam material 134 when the mounting substrate 102 and the surface acoustic wave element 150 are attached is lowered. When the above upper limit is exceeded, the adhesiveness between the mounting substrate 102 and the surface acoustic wave element 150 may deteriorate.

  The photopolymerizable resin may contain an epoxy vinyl ester resin. Thereby, since it radical-polymerizes with a polyfunctional monomer at the time of exposure, the intensity | strength of the dam material 134 can be raised. On the other hand, during development, the solubility in an alkaline developer is improved, so that residues after development can be reduced.

  Epoxy vinyl ester resins include 2-hydroxy-3-phenoxypropyl acrylate, Epolite 40E methacrylic adduct, Epolite 70P acrylic acid adduct, Epolite 200P acrylic acid adduct, Epolite 80MF acrylic acid adduct, Epolite 3002 methacrylic acid adduct. Epolite 3002 acrylic acid adduct, Epolite 1600 acrylic acid adduct, bisphenol A diglycidyl ether methacrylic acid adduct, bisphenol A diglycidyl ether acrylic acid adduct, Epolite 200E acrylic acid adduct, Epolite 400E acrylic acid adduct, etc. There is.

  Although content of epoxy vinyl ester resin is not specifically limited, 3 to 30 weight% of the whole resin composition for dam materials which comprises the dam material 134 is preferable. If the above upper limit is exceeded, the water absorption characteristics of the dam material 134 will deteriorate, and condensation will easily occur. If it is less than the said lower limit, the solubility with respect to the alkaline developing solution of the dam material 134 may be insufficient, and a residue may generate | occur | produce after image development. In particular, it is preferable to be in the range of 5 to 15% by weight. By doing so, it is possible to further reduce foreign matters remaining on the surfaces of the mounting substrate 102 and the surface acoustic wave element 150 after being attached.

  Moreover, it is preferable that the dam material 134 contains a photoinitiator. Thereby, the dam material 134 can be efficiently patterned by photopolymerization.

  Examples of the photopolymerization initiator include benzophenone, acetophenone, benzoin, benzoin isobutyl ether, methyl benzoin benzoate, benzoin benzoic acid, benzoin methyl ether, benzylfinyl sulfide, benzyl, dibenzyl, diacetyl and the like.

  Although content of a photoinitiator is not specifically limited, 0.5 to 5.0 weight% of the whole resin composition for dam materials is preferable, and 0.8 to 3.0 weight% is especially preferable. If the content is less than the lower limit, the effect of initiating photopolymerization may be reduced, and if the content exceeds the upper limit, the reactivity may be too high and storage stability and resolution may be reduced.

  In addition, although the dam material 134 may contain an inorganic filler, it is 9 weight% or less of the whole dam material resin composition which comprises the dam material 134. As shown in FIG. Exceeding this upper limit is not preferable because foreign matter due to the inorganic filler adheres to the substrate or undercut occurs. In this embodiment, the inorganic filler may not be included.

  By setting the inorganic filler to 9% by weight or less of the resin composition, the light transmittance of the dam material 134 can be improved. At this time, as a method for measuring the transmittance of the dam material 134, for example, a dam material 134 having a thickness of 25 μm is prepared and measured using a UV-visible spectrometer (model number: UV-160A, manufactured by Shimadzu Corporation). Wavelength: A method in which the transmittance is measured at 200 to 1000 nm and the transmittance at a wavelength of 365 nm is used as a measured value is used.

  Examples of inorganic fillers include fibrous fillers such as alumina fibers and glass fibers, acicular fillers such as potassium titanate, wollastonite, aluminum borate, acicular magnesium hydroxide, and whiskers, talc, mica, and sericite. , Glass flakes, flake graphite, plate-like fillers such as plate-like calcium carbonate, spherical fillers such as calcium carbonate, silica, fused silica, fired clay and unfired clay, porous fillings such as zeolite and silica gel Materials and the like. These may be used alone or in combination of two or more. Among these, a porous filler is preferable.

  Although the average particle diameter of an inorganic filler is not specifically limited, 0.01-90 micrometers is preferable and especially 0.1-40 micrometers is preferable. If the average particle diameter exceeds the above upper limit value, the film may have an abnormal appearance or poor resolution, and if it is less than the lower limit value, it may result in poor adhesion at the time of heat pasting. The average particle diameter can be evaluated using, for example, a laser diffraction particle size distribution analyzer SALD-7000 (manufactured by Shimadzu Corporation).

  A porous filler may be used as the inorganic filler. When a porous filler is used as the inorganic filler, the average pore diameter of the porous filler is preferably 0.1 to 5 nm, particularly preferably 0.3 to 1 nm. If the average pore diameter exceeds the above upper limit, a part of the resin component may enter the pores and the reaction may be hindered. If the average pore diameter is less than the lower limit, the water absorption capacity is reduced. The rate may decrease.

  In addition to the curable resin and filler described above, the resin composition for the dam material constituting the dam material 134 includes addition of a plastic resin, a leveling agent, an antifoaming agent, a coupling agent and the like as long as the object of the present invention is not impaired. An agent can be contained.

  The dam material 134 obtained by curing the resin composition for a dam material described above has a characteristic that the elastic modulus is low. The low stress property of the dam material 134 can suppress solder cracks and improve reliability.

As a method for measuring the elastic modulus of the dam material 134, for example, first, the dam material 134 obtained from the resin composition for the dam material is irradiated with 700 mJ / cm ² of light having a wavelength of 365 nm, and then the dam material 134 is exposed. The storage elastic modulus G ′ of the material 134 is measured with a dynamic viscoelasticity measuring device Rheo Stress RS150 (manufactured by HAAKE, measurement frequency: 1 Hz, gap interval: 100 μm, measurement temperature range: 25 to 200 ° C., heating rate 10 ° C./min). Is used to determine the elastic modulus at a predetermined temperature. The predetermined temperature is, for example, 80 ° C., but is not limited thereto, and various temperatures can be adopted.

When the elastic modulus at 80 ° C. of the dam material 134 is measured, the dam material 134 exposes light of all wavelengths with a mercury lamp, and the accumulated exposure amount becomes 700 mJ / cm ² with i-line (365 nm) light. Thus, it is preferable that the elasticity modulus in 80 degreeC after exposure is 100 Pa or more, and 500-30000 Pa is especially preferable. If it is less than the above lower limit, the shape retention property when the mounting substrate 102 and the surface acoustic wave element 150 are attached is lowered. When the upper limit is exceeded, it becomes difficult to attach the mounting substrate 102 and the surface acoustic wave element 150 after patterning.

Further, the dam material 134 preferably has a moisture permeability measured by the JIS Z0208 B method of 12 [g / m ² · 24 h] or more, particularly preferably 14 to 100 [g / m ² · 24 h]. If it is less than the above lower limit value, the condensation of the surface acoustic wave element 150 and the like of the surface acoustic wave device 100 may not be sufficiently prevented. When the upper limit is exceeded, the moisture absorption reflow reliability of the dam material 134 may be lowered.

As a method for measuring the moisture permeability, for example, a dam material is bonded using a laminator set at 60 ° C. to produce a dam material 134 having a film thickness of 100 μm, and an exposure amount is 700 mJ / cm using an exposure machine. ² After irradiating with light (wavelength 365 nm), thermosetting at 180 ° C./2 hours. The obtained cured dam material 134 is evaluated in an environment of 40 ° C./90% according to a moisture permeable cup method (JIS Z0208 B method), and a method for obtaining a moisture permeability is used. According to this moisture permeable cup method, the moisture permeability of the dam material 134 itself can be evaluated.

  In the present invention, since the dam material 134 itself has excellent moisture permeability, moisture in the space 190 (FIG. 1) inside the surface acoustic wave device 100 composed of the mounting substrate 102, the surface acoustic wave element 150, and the dam material 134 is removed from the outside. In addition, it is possible to prevent moisture from entering from the outside. With this characteristic, it is considered that the dam material 134 can contribute to the improvement of the airtightness of the space 190 of the surface acoustic wave device 100.

  On the other hand, as a method for evaluating the airtightness of the surface acoustic wave device 100, for example, a constant temperature and humidity bias test (HHBT) can be used. This HHBT measures resistance value for about 1000 hours using conditions: 85 ° C., 85%, 1 to 20 V, apparatus: constant temperature and humidity chamber. If the hollow portion (space 190) is hermetically sealed, moisture does not enter the inside, so the resistance value does not decrease. As the constant temperature and humidity chamber, for example, PH-K series (manufactured by ESPEC Corporation) can be used. According to the HHBT, the airtightness of the surface acoustic wave device 100 can be confirmed. According to this method, the airtightness of the surface acoustic wave device 100 according to the present invention is excellent. As described above, this is a result of the contribution of the airtightness improvement of the hollow portion (space 190) by the dam material 134 also having adhesiveness to the surface acoustic wave element 150 and the moisture permeability property of the dam material 134 itself. It is guessed. That is, it is considered that the airtightness of the surface acoustic wave device 100 is improved if the adhesiveness of the dam material 134 to the mounting substrate 102 and the surface acoustic wave element 150 and the moisture permeability of the dam material 134 are excellent.

Next, the mounting substrate 102 according to the present embodiment will be described in detail.
The mounting substrate 102 according to the present invention is formed by molding at least one prepreg formed by impregnating a fiber base material with a base material resin composition.
A resin composition for a substrate according to the present invention is a resin composition used to form a sheet-like prepreg by impregnating a fiber substrate, and is substantially halogenated with a cyanate resin and / or a prepolymer thereof. An epoxy resin containing no atom, an imidazole compound, and an inorganic filler, the epoxy resin comprising: a first epoxy resin; and a second epoxy resin having a weight average molecular weight higher than that of the first epoxy resin. The first epoxy resin is an arylalkylene type epoxy resin, and the weight average molecular weight of the second epoxy resin is 5000 or more. The prepreg of the present invention is obtained by impregnating a fiber base material with the above-described resin composition for base material.

  In the linear expansion coefficient (α1) of the cured product of the resin composition for a substrate according to the present invention (hereinafter sometimes simply referred to as “cured product”), the cured product has a temperature of 25 ° C. or higher and a glass transition temperature (Tg) or lower. In this region, the linear expansion coefficient (α1) in the xy plane direction is 18 ppm / ° C. or less, and more preferably 11 ppm / ° C. or less. Further, the lower limit value of the linear expansion coefficient (α1) in the xy plane direction is not particularly limited, but can be set to, for example, 5 ppm / ° C. or more. Thereby, when the cured product is used for the surface acoustic wave device 100 or the surface acoustic wave element substrate 200, peeling of the conductor circuit layer and generation of cracks can be suppressed in a thermal shock test such as a thermal cycle test. Moreover, the curvature of the board | substrate at the time of press molding or solder reflow can also be suppressed.

  Moreover, in the linear expansion coefficient ((alpha) 1) of the hardened | cured material of the resin composition for base materials which concerns on this invention, the linear expansion coefficient of the z plane direction in the area | region of 25 degreeC or more and a glass transition temperature (Tg) or less of hardened | cured material. (Α1) is 55 ppm / ° C. or less, more preferably 16 ppm / ° C. or less. Further, the lower limit value of the linear expansion coefficient (α1) in the z-plane direction is not particularly limited, but may be, for example, 5 ppm / ° C. or more. Thereby, when the cured product is used for the surface acoustic wave device 100 or the surface acoustic wave element substrate 200, peeling of the conductor circuit layer and generation of cracks can be suppressed in a thermal shock test such as a thermal cycle test. Moreover, the curvature of the board | substrate at the time of press molding or solder reflow can also be suppressed. In addition, since the difference in thermal expansion coefficient between the mounting substrate 102 and the dam material 134 can be reduced, warpage of the mounting substrate 102 can be reduced, and damage to the mounting substrate 102 can be suppressed. Furthermore, since the difference in thermal expansion coefficient between the surface acoustic wave element 150 and the mounting substrate 102 can be reduced, the generation of cracks due to warpage can be suppressed, and the highly reliable surface acoustic wave device 100 can be manufactured with high yield. .

  Here, as a method of measuring the linear expansion coefficient (α1), a method of measuring the linear expansion coefficient in the thickness direction of the substrate and in the substrate plane using TMA (manufactured by TA Instruments) is used.

  The glass transition temperature (Tg) of the cured product of the resin composition for a substrate according to the present invention is 160 ° C. or higher, more preferably 220 ° C. or higher, when measured using TMA (TA Instruments). It is. Further, this glass transition temperature (Tg) is 180 ° C. or higher, more preferably 260 ° C. or higher, when measured using DMA (manufactured by TA Instruments). Thereby, in the mounting board | substrate 102, since a low thermal expansion coefficient can be maintained in a wide temperature range, generation | occurrence | production of curvature can be suppressed suitably. Furthermore, the adhesion of the bonding surface between the mounting substrate 102 and the dam material 134 can be improved in a wide temperature range.

  If the linear expansion coefficient exceeds the above upper limit value, this also causes a mismatch of the linear expansion with the conductor circuit, causing warpage of the substrate during press molding or solder reflow, and peeling of the conductor circuit layer in thermal shock tests such as a thermal cycle test. There is a possibility that the generation of cracks cannot be suppressed.

  In addition, the linear expansion coefficient of the hardened | cured material of the resin composition for base materials depends on the kind of resin, resin content, the kind of filler, and the quantity of filler. In the present invention, the linear expansion coefficient can be arbitrarily set by adjusting the selection of the resin, the content of the selected resin and the content of the imidazole compound or the selected inorganic filler. However, as the content of the inorganic filler increases, the moldability at the time of producing the substrate deteriorates and the yield decreases, so the lower limit of the linear expansion coefficient is substantially limited to the above range.

  Although the hardened | cured material of the resin composition for base materials of this invention is not specifically limited, The weight decreasing rate in 300 degreeC is 15% or less. Thereby, when a hardened | cured material is used for a laminated board or a semiconductor device, the solder heat resistance after moisture absorption can be improved. The weight reduction rate is preferably 10% or less. Thereby, the said effect | action can be expressed effectively. The weight reduction rate was determined by raising the temperature of the sample from 30 ° C. to 500 ° C. at 10 ° C./min by TG-DTA (differential thermogravimetric simultaneous measurement), and tracking the weight change of the sample ((30 It was set as the value calculated | required by the sample weight of (degreeC)-(sample weight of 300 degreeC) / (sample weight of 30 degreeC) x100.

Hereinafter, the resin composition for a substrate will be further described.
The base resin composition of the present invention contains a cyanate resin and / or a prepolymer thereof. Thereby, a flame retardance can be improved.
The cyanate resin and / or prepolymer thereof can be obtained, for example, by reacting a cyanogen halide with a phenol and prepolymerizing it by a method such as heating as necessary. Specific examples include bisphenol type cyanate resins such as novolac type cyanate resin, bisphenol A type cyanate resin, bisphenol E type cyanate resin, and tetramethylbisphenol F type cyanate resin. Among these, novolac type cyanate resin is preferable. Thereby, the heat resistance improvement by a crosslinking density increase and the flame retardance of the resin composition for base materials etc. can be improved. This is probably because the novolac cyanate resin has a high proportion of benzene rings due to its structure and is easily carbonized.

  As the novolak type cyanate resin, for example, those represented by the formula (I) can be used.

  The weight average molecular weight of the novolak cyanate resin represented by the above formula (I) is not particularly limited, but is preferably 500 to 4,500, and particularly preferably 600 to 3,000. When the weight average molecular weight of the novolak-type cyanate resin is less than the above lower limit value, the mechanical strength may be reduced, and when the upper limit value is exceeded, the curing rate of the resin composition for the base material is high, resulting in a decrease in storage stability. There is. The novolak-type cyanate resin can be obtained, for example, by reacting an arbitrary novolak resin with a compound such as cyanogen chloride or cyanogen bromide.

  Although content of the said cyanate resin is not specifically limited, 5 to 60 weight% of the whole resin composition is preferable, and 15 to 35 weight% is especially preferable. If the content of the cyanate resin is less than the lower limit, the effect of increasing the heat resistance and lowering the thermal expansion may be reduced, and if the upper limit is exceeded, the crosslinking density increases and the free volume increases, resulting in moisture resistance. May decrease.

In the resin composition for a substrate according to the present invention, an epoxy resin substantially free of halogen atoms is used. Thereby, a water absorption rate can be reduced. Examples of the epoxy resin include a phenol novolac type epoxy resin, a bisphenol type epoxy resin, a naphthalene type epoxy resin, and an arylalkylene type epoxy resin. Among these, aryl alkylene type epoxy resins are preferable. Thereby, a flame retardance can be improved.
The phrase “substantially free of halogen atoms” means that the content of halogen atoms in the epoxy resin is, for example, 1% by weight or less.

  Although content of the said epoxy resin is not specifically limited, 5 to 60 weight% of the whole resin composition for base materials is preferable, and 15 to 40 weight% is especially preferable. If the content is less than the lower limit, the effect of improving the adhesion and film-forming property may be reduced, and if the content exceeds the upper limit, the low thermal expansion characteristic of the present invention may be reduced.

  Moreover, although the said epoxy resin is not specifically limited, It is preferable that it is a mixture of the 1st epoxy resin and the 2nd epoxy resin whose weight average molecular weight is higher than the said 1st epoxy resin. Thereby, it is possible to achieve both circuit embedding and flow control during press molding.

  Examples of the first epoxy resin include phenol novolac type epoxy resins, bisphenol type epoxy resins, naphthalene type epoxy resins, arylalkylene type epoxy resins and the like. Among these, aryl alkylene type epoxy resins are preferable. Thereby, a flame retardance and moisture absorption solder heat resistance can be improved.

  Here, the aryl alkylene type epoxy resin refers to an epoxy resin having one or more aryl alkylene groups in a repeating unit. For example, a xylylene type epoxy resin, a biphenyl dimethylene type epoxy resin, etc. are mentioned. Among these, a biphenyl dimethylene type epoxy resin is preferable. The biphenyl dimethylene type epoxy resin can be represented by, for example, the formula (II).

  Although n of the biphenyl dimethylene type | mold epoxy resin shown by the said Formula (II) is not specifically limited, 1-10 are preferable and 2-5 are especially preferable. If the amount is less than this, the biphenyldimethylene type epoxy resin is easily crystallized, and the solubility in a general-purpose solvent is relatively lowered, which may make handling difficult. Moreover, when more than this, the fluidity | liquidity of resin will fall and it may become a cause of a molding defect.

  The weight average molecular weight of the first epoxy resin is not particularly limited, but is preferably 4,000 or less, particularly preferably 500 to 4,000, and most preferably 800 to 3,000. If the weight average molecular weight is less than the above lower limit value, tack may occur on the mounting substrate 102 with metal foil, and if it exceeds the above upper limit value, solder heat resistance may be reduced.

  Although content of the said 1st epoxy resin is not specifically limited, 3 to 30 weight% of the whole resin composition for base materials is preferable, and 5 to 20 weight% is especially preferable. When the content is within the above range, the moisture-absorbing solder heat resistance can be particularly improved.

  Examples of the second epoxy resin include phenol novolac type epoxy resins, bisphenol type epoxy resins, naphthalene type epoxy resins, arylalkylene type epoxy resins, and the like. Among these, bisphenol type epoxy resins are preferable. Thereby, adhesiveness with copper foil etc. can be improved.

  The weight average molecular weight of the second epoxy resin is not particularly limited, but is preferably 5,000 or more, particularly preferably 5,000 to 100,000, and most preferably 8,000 to 80,000. If the weight average molecular weight is less than the lower limit, the effect of improving the film forming property of the mounting substrate 102 with metal foil may be reduced, and if the upper limit is exceeded, the solubility of the epoxy resin may be reduced.

  Although content of the said 2nd epoxy resin is not specifically limited, 3 to 30 weight% of the whole resin composition for base materials is preferable, and 5 to 20 weight% is especially preferable. When the content is within the above range, it is possible to improve the film forming property particularly when the metal foil-mounted mounting substrate 102 is produced and the inner layer circuit adhesion property when producing the multilayer printed wiring board.

The resin composition of the present invention contains an imidazole compound. Thereby, reaction of the said cyanate resin can be accelerated | stimulated, without reducing the insulation of the resin composition for base materials.
Examples of the imidazole compound include 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2,4-diamino-6- [2'-Methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- (2'-undecylimidazolyl) -ethyl-s-triazine, 2,4-diamino-6 Mention may be made of [2'-ethyl-4-methylimidazolyl- (1 ')]-ethyl-s-triazine. Among these, imidazole compounds having two or more functional groups selected from an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a hydroxyalkyl group, and a cyanoalkyl group are preferable, and 2-phenyl-4,5 is particularly preferable. -Dihydroxymethylimidazole is preferred. Thereby, the heat resistance of the resin composition for base materials and the thermal expansion of the obtained insulating layer can be reduced, and the water absorption can be reduced.

  Although content of the said imidazole compound is not specifically limited, 0.05 to 5 weight% of the resin composition for base materials is preferable, and 0.2 to 2 weight% is especially preferable. When the content is within the above range, the heat resistance can be particularly improved.

The base material resin composition according to the present invention contains an inorganic filler. Thereby, low thermal expansion and improvement in flame retardance can be achieved.
Further, the elastic modulus can be improved by a combination of the cyanate resin and / or its prepolymer (particularly a novolac-type cyanate resin) and an inorganic filler.

  Examples of the inorganic filler include talc, alumina, glass, silica, mica and the like. Among these, silica is preferable, and fused silica is preferable in that it has excellent low expansibility. The shape is crushed and spherical, but in order to reduce the melt viscosity of the resin composition for the base material in order to ensure the impregnation property to the glass base material, there is a usage method that suits the purpose, such as using spherical silica. Adopted.

  The average particle size of the inorganic filler is not particularly limited, but is preferably 0.01 to 5 μm, particularly preferably 0.2 to 2 μm. If the particle size of the inorganic filler is less than the lower limit, the viscosity of the varnish becomes high, which may affect the workability when manufacturing the mounting substrate 102 with a metal foil. Moreover, when the said upper limit is exceeded, phenomena, such as sedimentation of an inorganic filler, may occur in a varnish. Further, spherical fused silica having an average particle size of 5 μm or less is preferable, and spherical fused silica having an average particle size of 0.01 to 2 μm is particularly preferable. Thereby, the filling property of an inorganic filler can be improved.

  The content of the inorganic filler is preferably from 30 to 70% by weight, particularly preferably from 40 to 60% by weight, based on the entire base resin composition. If the content is less than the above lower limit value, the effect of low thermal expansion and low water absorption may be reduced, and if it exceeds the upper limit value, moldability may be reduced due to a decrease in fluidity.

  Although it does not specifically limit in the resin composition for base materials which concerns on this invention, It is preferable to contain a coupling agent further. The coupling agent improves the wettability of the interface between the resin and the inorganic filler, thereby uniformly fixing the resin and the filler to the base material (mounting substrate 102), heat resistance, particularly solder after moisture absorption Blended to improve heat resistance.

  As the coupling agent, any of those usually used can be used, and among these, one kind selected from an epoxy silane coupling agent, a titanate coupling agent, an aminosilane coupling agent, and a silicone oil type coupling agent. It is preferable to use the above coupling agent. Thereby, wettability with the interface of an inorganic filler can be made high, and heat resistance can be improved more.

  Although content of the said coupling agent is not specifically limited, 0.05-3 weight part is preferable with respect to 100 weight part of inorganic fillers. If the content is less than the above lower limit value, the inorganic filler cannot be sufficiently coated and the effect of improving the heat resistance may be reduced. If the content exceeds the above upper limit value, the bending strength of the mounting substrate 102 with metal foil is reduced. There is a case.

  The resin composition for base materials according to the present invention can be added with additives other than the above components as necessary within a range that does not impair the characteristics. Examples of the additive include an antifoaming material and a leveling material.

Next, the prepreg will be described.
The prepreg according to the present invention is obtained by impregnating a fiber substrate with the above-described resin composition for a substrate. Thereby, it is possible to obtain a prepreg suitable for manufacturing a printed wiring board excellent in various characteristics such as dielectric characteristics, mechanical and electrical connection reliability under high temperature and high humidity.

As the fiber base material used in the present invention, glass fiber base materials such as glass woven fabric and glass nonwoven fabric, polyamide resin fibers, aromatic polyamide resin fibers, polyamide resin fibers such as wholly aromatic polyamide resin fibers, polyester resin fibers, Synthetic fiber substrate, kraft paper, cotton linter composed of woven or non-woven fabric mainly composed of aromatic polyester resin fiber, polyester resin fiber such as wholly aromatic polyester resin fiber, polyimide resin fiber, fluororesin fiber, etc. Examples thereof include organic fiber base materials such as paper base materials mainly composed of paper, mixed paper of linter and kraft pulp, and the like. Among these, a glass fiber base material is preferable. Thereby, the intensity | strength of a prepreg can go up and water absorption can be made low. In addition, the linear expansion coefficient of the prepreg can be reduced.

  In the method of impregnating the fiber base material with the resin composition for base material obtained in the present invention, for example, a resin varnish is prepared using the resin composition for base material of the present invention, and the fiber base material is immersed in the resin varnish. For example, a coating method using various coaters, and a spraying method. Among these, the method of immersing the fiber base material in the resin varnish is preferable. Thereby, the impregnation property of the resin composition for base materials with respect to a fiber base material can be improved. In addition, when a fiber base material is immersed in a resin varnish, a normal impregnation coating equipment can be used.

  The solvent used in the resin varnish desirably exhibits good solubility with respect to the resin component in the resin composition for a substrate, but a poor solvent may be used within a range that does not adversely affect the resin varnish. Examples of the solvent exhibiting good solubility include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve and carbitol.

  The nonvolatile content concentration in the resin varnish is not particularly limited, but is preferably 40 to 80% by weight, and particularly preferably 50 to 65% by weight. Thereby, the viscosity of a resin varnish can be adjusted to a suitable range, and the impregnation property to a fiber base material can be improved further. A prepreg can be obtained by impregnating a fiber substrate with a resin composition for a substrate and drying at a predetermined temperature, for example, 80 to 200 ° C.

Next, the mounting substrate 102 (laminated plate) will be described.
The mounting substrate 102 according to the present invention is formed by molding at least one prepreg described above. As a result, it is possible to obtain the mounting substrate 102 having excellent dielectric characteristics and mechanical and electrical connection reliability under high temperature and high humidity.

  In the case of a single prepreg, a metal foil or film is stacked on both upper and lower surfaces or one surface. Two or more prepregs can be laminated. When two or more prepregs are laminated, a metal foil or film is laminated on the outermost upper and lower surfaces or one surface of the laminated prepregs. Next, the mounting substrate 102 with a metal foil can be obtained by heating and pressurizing a laminate of a prepreg and a metal foil or the like. The heating temperature is not particularly limited, but is preferably 120 to 220 ° C, particularly preferably 150 to 200 ° C. Moreover, the pressure to pressurize is not particularly limited, but is preferably 2 to 5 MPa, and particularly preferably 2.5 to 4 MPa.

Examples of the metal constituting the metal foil include copper and copper alloys, aluminum and aluminum alloys, silver and silver alloys, gold and gold alloys, zinc and zinc alloys, nickel and nickel alloys, tin and tin. Alloy, iron, iron alloy and the like.
Examples of the film include polyethylene, polypropylene, polyethylene terephthalate, polyimide, and fluorine resin.

Next, a multilayer printed wiring board will be described.
A multilayer printed wiring board can be used as the mounting substrate 102 according to the present invention. This multilayer printed wiring board is a multilayer printed wiring board in which the mounting board 102 with metal foil is superposed on one or both sides of the inner layer circuit board and heated and pressed. A mounting board 102 with metal foil is superposed on one or both sides of the inner layer circuit board and heated and pressed to obtain a multilayer printed wiring board. Although the temperature to heat is not specifically limited, 140-240 degreeC is preferable. Although the pressure to pressurize is not specifically limited, 10-40 kg / cm < ² > is preferable.
Examples of the inner layer circuit board include a circuit formed on both sides of a copper-clad laminate and blackened.
Moreover, the multilayer printed wiring board which concerns on this invention has an insulating layer formed from the resin composition for base materials which concerns on the said invention.

Next, the effect of this embodiment is demonstrated.
In the surface acoustic wave device 100 of the present embodiment, the mounting substrate 102 and the surface acoustic wave element 150 are provided to face each other with the dam material 134 interposed therebetween. Since the dam material 134 has adhesiveness to the surface acoustic wave element 150, the surface acoustic wave element 150 and the mounting substrate 102 can be brought into close contact with each other. Thereby, the airtightness of the space 190 inside the surface acoustic wave device 100 including the mounting substrate 102, the surface acoustic wave element 150, and the dam material 134 can be improved. The airtight structure by the dam material 134 can prevent the intrusion of the external atmosphere and the infiltration of the sealing material.

  In particular, in the surface acoustic wave device 100 in which the side surface of the dam material 134 is exposed, the side surface of the dam material 134 having high moisture permeability is exposed. Accordingly, moisture trapped in the internal space 190 when the mounting substrate 102 and the surface acoustic wave element 150 are attached can be released to the outside, and the moisture enters the inside through the dam material 134 after being attached. Can be prevented. Therefore, the dam material 134 can suppress the occurrence of condensation and can maintain the airtightness of the space 190. In the surface acoustic wave device 100, the dielectric characteristics are maintained.

  Moreover, in the dam material 134 which concerns on this invention, the light transmittance of the dam material 134 can be improved by making an inorganic filler into 9 weight% or less of a resin composition. Thereby, the developability of the dam material 134 is improved and the crosslinking density of the acrylic polyfunctional monomer of the photopolymerizable resin is improved. Due to the improvement in developability, it is possible to prevent the developer from seeping into the dam material 134 during development, and to prevent occurrence of undercut. Thereby, the surface acoustic wave device 100 can be manufactured with a high yield. On the other hand, the shape retention of the dam material 134 can be maintained by improving the crosslinking density. For this reason, the functional surface hollow of the surface acoustic wave element 150 including the space 190 can be secured, and the reliability of the surface acoustic wave device 100 can be improved.

  On the other hand, in the mounting substrate 102 according to the present invention, since a low thermal expansion coefficient can be maintained in a wide temperature range, occurrence of warpage can be suitably suppressed. Since the dam material 134 having low stress is provided on the rigid mounting substrate 102, solder ball cracks can be suppressed. Therefore, in the surface acoustic wave device 100, connection reliability can be improved.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

The structure of the surface acoustic wave device 100 according to the present invention is not limited to the structure shown in FIG.
For example, other examples of the structure of the surface acoustic wave device 100 are shown in FIGS.
In the surface acoustic wave device 100 shown in FIG. 7A, the side surface of the dam material 134 can be covered with the mold resin 160. Thereby, since the dam material 134 which is a junction part of the mounting substrate 102 and the surface acoustic wave element 150 can be sealed, the airtightness of the space 190 can be further improved. At this time, as described above, the sealing material (mold resin 160) can be prevented from entering due to the airtight structure of the dam material 134.

  In the manufacturing process of the surface acoustic wave element substrate 200 used in the surface acoustic wave device 100 shown in FIG. 7A, a plurality of frame-shaped dam materials 134 are formed, and a mold resin 160 is provided between the dam materials 134. And is cut at the mold resin 160 portion. At this time, the area of the outer peripheral portion of the dam material 134 may be the same as or larger than the area of the surface acoustic wave element 150. Moreover, each dam material 134 does not need to be connected as a sheet. This cutting position can be determined by the mark.

  On the other hand, the surface acoustic wave device 100 shown in FIG. 7B can have a structure in which the side surface of the dam material 134 is exposed. In the manufacturing process of the surface acoustic wave device substrate 200 used in the surface acoustic wave device 100 shown in FIG. 7B, the dam material 134 is formed in a lattice shape connected as one sheet. Thereby, in the molding resin 160 formation process, since the molding resin 160 is not formed between the dam materials 134, the side surfaces of the dam materials 134 can be easily exposed when the dam materials 134 are separated. At this time, the dam material 134 is diced.

The structure of the surface acoustic wave element substrate 200 according to the present embodiment is not limited to the filled via structure shown in FIG. 2, and various structures can be taken.
For example, another example of the structure of the surface acoustic wave element substrate is shown in FIG.
A surface acoustic wave element substrate 210 shown in FIG. 8 has a bump plating structure. Hereinafter, the manufacturing process of the substrate 210 for a surface acoustic wave element having a bump plating structure will be described with reference to FIGS. However, only the steps different from the filled via structure shown in FIG. 2 will be described, and the same steps will be omitted as appropriate.

First, copper foils (first metal foil 104 and second metal foil 106) are formed on both surfaces of the mounting substrate 102 (FIG. 9A). Subsequently, a blind via 110 is formed on the upper surface of the mounting substrate 102 with a UV laser or the like (FIG. 9B). Bump plating is performed to form vias 136 (FIG. 10A). At this time, a barrier film (Ni plating 138) and a solder layer 140 are formed on the via 136. Next, a protective sheet 124 is attached (FIG. 10B). Then, a desired second circuit 142 is formed by, for example, etching the first metal foil 104 on the lower surface of the mounting substrate 102 (FIG. 10C). Further, the photosensitive insulating resin layer 128, the Ni film 130, and the Au film 132 are formed (FIG. 11A), and the protective sheet 124 is peeled off (FIG. 11B). Thereafter, a dam material 134 is formed on the mounting substrate 102 (FIG. 11C).
Through the steps described above, a surface acoustic wave element substrate 210 having a bump plating structure is obtained (FIG. 8).

  Moreover, when using the dam material 134 which has the adhesiveness based on this invention, as a material which comprises the said mounting substrate 102, a resin film base material etc. may be sufficient, for example. Examples of the resin film substrate include polyimide resin films such as polyimide resin films, polyetherimide resin films, polyamideimide resin films, polyamide resin films such as polyamide resin films, and polyester resin films such as polyester resin films. Can be mentioned. Of these, a polyimide resin film is particularly preferably used from the viewpoint of improving the elastic modulus and heat resistance.

  The material of the photosensitive insulating resin layer 128 is not particularly limited, and the same material as the dam material 134 may be used.

Example 1
(Fabrication of FR-5 equivalent substrate)
The FR-5 equivalent substrate is obtained by the following steps (1) to (3). Each step will be described below.
(1) Preparation of resin varnish 14.0 parts by weight of biphenylaralkyl type novolak epoxy resin (Nippon Kayaku Co., Ltd., NC-3000) as an epoxy resin, biphenyldimethylene type phenolic resin (manufactured by Nippon Kayaku Co., Ltd.) 10.8 parts by weight of GPH-103) and 24.6 parts by weight of a novolak cyanate resin (manufactured by Lonza Japan, Primaset PT-30) were dissolved and dispersed in methyl ethyl ketone. Furthermore, 49.8 parts by weight of spherical fused silica (manufactured by Admatechs, “SO-25R”, average particle size 0.5 μm) as an inorganic filler, and silane coupling agent (manufactured by Nippon Unicar Co., A187) as a coupling agent 0.2 part by weight, 0.6 part by weight of a dye containing an anthraquinone compound as a colorant (manufactured by Nippon Kayaku Co., Ltd., Kayase Black A-N) is added and stirred for 10 minutes using a high-speed stirrer, A resin varnish having a solid content of 50% by weight was prepared.
(2) Manufacture of prepreg The above-mentioned resin varnish was impregnated into a glass woven fabric (thickness 42 μm, manufactured by Nitto Boseki Co., Ltd., WEA-1078) and dried in a heating furnace at 150 ° C. for 2 minutes. About 60% by weight of prepreg was obtained.
(3) Manufacture of laminated board The above-mentioned prepreg was laminated with 12 μm copper foil on both sides, and heat-pressed at a pressure of 4 MPa and a temperature of 200 ° C. for 2 hours to obtain a double-sided copper-clad FR-5 equivalent substrate. .

(Production of dam materials with adhesive function)
The dam material with an adhesive function is obtained by the following steps (1) to (3). Each step will be described below.
(1) Synthesis of alkali-soluble resin ((meth) acrylic modified bis A novolak resin) 60% solid MEK (methyl ethyl ketone) solution of novolac bisphenol A resin (Phenolite LF-4871, manufactured by Dainippon Ink & Chemicals, Inc.) 500 g was put into a 2 L flask, and 1.5 g of tributylamine as a catalyst and 0.15 g of hydroquinone as a polymerization inhibitor were added thereto, and the mixture was heated to 100 ° C. The glycidyl methacrylate 180.9g was dripped in 30 minutes in it, and it was made to react with stirring at 100 degreeC for 5 hours, and methacryloyl modified novolak-type bisphenol A resin MPN001 (methacryloyl modification rate 50%, "methacryl modification") of solid content 74%. Bis A novolac resin ") was obtained.
(2) Production of resin composition varnish for dam material 44.5% by mass of the synthesized methacryloyl-modified novolac bisphenol A resin MPN001 as an alkali-soluble resin and an epoxy resin as a thermosetting resin, bisphenol A Type epoxy resin (made by Japan Epoxy Resin, trade name: Epicoat 1001) 26 mass%, silicone modified epoxy resin (made by Toray Dow Corning Silicone Co., Ltd., trade name: BY16-115) 5.3 mass%, As a photopolymerizable resin, 18.7% by mass of triethylene glycol dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK Ester 3G) is a thermosetting resin and also acts as a curing agent for epoxy resin. Phenolic resin (manufactured by Sumitomo Bakelite Co., Ltd., trade name: PR-HF-6) 3.5 quality 2% dimethoxy-1,2-diphenylethane-1-one (manufactured by Ciba Specialty Chemicals Co., Ltd., trade name: Irgacure 651) as a photopolymerization initiator, (Methyl ethyl ketone, manufactured by Daishin Chemical Co., Ltd.) was dissolved in a photosensitive adhesive resin composition varnish having a solid content of 71%. The content of the methacryloyl-modified novolak bisphenol A resin MPN001 in the photosensitive adhesive resin composition varnish is a value in terms of solid content.
(3) Production of dam material A resin varnish is applied to a PET film (MRX50, thickness 50 μm) as a supporting substrate with a comma coater and dried at 80 ° C. for 20 minutes to form a dam material having a thickness of 20 μm. Obtained.

(Production of surface acoustic wave device)
First, the double-sided copper-clad FR-5 equivalent substrate (substrate thickness: 60 μm, each copper foil thickness: 12 μm) is prepared. Subsequently, half-etching was performed to increase the variation accuracy when forming the conformal mask, and the copper foil was etched to a thickness of 7 μm on both sides. Subsequently, a dry film resist (Tokyo Ohka Kogyo Co., Ltd .: AR-320, film thickness 20 μm) was laminated at 105 ° C. and 0.4 MPa. Subsequently, a conformal mask pattern (diameter: 45 μm) was exposed and developed at 40 mJ / cm ² , the copper foil was etched by 7 μm, and the dry film resist was peeled off to form a conformal mask.

Next, laser processing was performed on the conformally processed portion using a carbon dioxide gas laser processing machine (manufactured by Mitsubishi Electric, 605GTXIII), and a via hole having a diameter of 50 μm was formed. Subsequently, in order to remove the resin residue generated by this laser processing, it is immersed in a swelling solution (Atotech Japan Co., Ltd., Swelling Dip Securigant P) at 80 ° C. for 5 minutes, and further an aqueous potassium permanganate solution (Atotech Japan). (Concentrate Compact CP, manufactured by the company) After immersion at 80 ° C. for 5 minutes, the resin residue was removed (desmear) by immersion in a neutralization solution at 40 ° C. for 5 minutes.
Subsequently, the pre-dip solution (manufactured by Atotech Japan Co., Ltd., 25 ° C.) was applied for 5 minutes in a 50 ° C. cleaner liquid (Atotech Japan Co., Ltd., Cleaner Securigant 902). Dip Neo Gantt B) for 90 seconds, 35 ° C activator solution (Atotech Japan Co., Activator Neo Gantt B) for 5 minutes, 30 ° C reducer solution (Atotech Japan Co., Reducer Neo Gantt WA) for 5 minutes, 35 Electroless plating solution at 20 ° C. (Atotech Japan, MSK-DK) for 20 minutes).
Next, heat treatment was performed at 150 ° C. for 30 minutes. Subsequently, filled via plating (manufactured by Okuno Pharmaceutical Co., Ltd., Top Lucina NSV) was carried out as electrolytic plating to form a film having a thickness of 40 μm. Subsequently, in order to increase the variation accuracy during the formation of the surface circuit pattern, half etching was performed, and the copper foil was etched to a thickness of 7 μm on both sides. Further, a dry film resist (manufactured by Tokyo Ohka Kogyo Co., Ltd .: AR-320, film thickness 20 μm) is laminated on the substrate surface at 105 ° C. and 0.4 MPa, the circuit pattern is exposed at 40 mJ / cm ² and etched by 7 μm. A circuit pattern was formed on the substrate surface.
Subsequently, using the via hole connection, Ni plating and SnAg plating were performed on the via land on the substrate surface (Ni plating film thickness: 4 μm, SnAg plating film thickness: 15 μm). At this time, an electrode was taken from the back surface of the substrate, and a mask was applied so that plating did not adhere to the back surface, and plating was performed only on the substrate surface.
Next, using a vacuum pressure laminator (MVLP-500 / 600IIA manufactured by Meiki Seisakusho Co., Ltd.) to protect the bump surface, a back sheet (Somar Corporation, PS-503WA) is pasted on the substrate surface at 0.4 MPa. It was. A dry film resist (manufactured by Tokyo Ohka Kogyo Co., Ltd .: AR-320, film thickness 20 μm) is laminated on the back surface of the substrate at 105 ° C. and 0.4 MPa, the circuit pattern is exposed at 40 mJ / cm ² , and etched by 7 μm. A circuit pattern on the back surface was formed. Furthermore, a photosensitive cover lay (manufactured by Hitachi Chemical Co., Ltd .: FR5625, film thickness 25 μm) is laminated on the back surface of the substrate at 0.4 MPa using a vacuum pressure laminator (manufactured by Meiki Seisakusho, MVLP-500 / 600IIA). The pattern was exposed and developed at 250 mJ / cm ² . Subsequently, post UV was exposed at 100 mJ / cm ² and post cure was performed at 160 ° C. for 60 minutes to form a surface coating. Furthermore, for Cu plating coating, electroless Ni plating (film thickness: 4 μm) was performed, and electroless Au plating (film thickness: 0.05 μm) was performed. Then, the back sheet (Somar Corporation, PS-503WA) on the substrate surface was peeled off.

Next, the above-mentioned dam material with an adhesive function (film thickness: 20 μm) is laminated on the substrate surface at 60 ° C. and 0.4 MPa using a vacuum pressurization type laminator (MVLP-500 / 600IIA, manufactured by Meiki Seisakusho) Heat treatment was performed at 60 ° C. for 3 minutes. Subsequently, the pattern was exposed at 200 mJ / cm ² , and heat treatment was performed at 60 ° C. for 5 minutes within 30 minutes in order to stop the reaction after exposure. Thereafter, development was performed to form a dam material (adhesive film) on the substrate surface. Through the above steps, a surface acoustic wave device substrate was obtained.

  Next, using a flip chip bonder (manufactured by Panasonic Corporation, FCB3), an oxide single crystal (LT) chip was temporarily pressure-bonded at 200 ° C. on the surface of the substrate manufactured by the above process. Furthermore, a reflow process (peak temperature: 260 ° C.) was performed to join SnAg. Thereafter, an epoxy resin (mold resin) was applied by transfer molding, and dicing was performed to obtain a surface acoustic wave device. At this time, the side surface of the dam material of the surface acoustic wave device was exposed.

(Example 2)
In Example 1, it carried out similarly to Example 1 except dicing so that the side surface of the dam material of a surface acoustic wave apparatus might be covered with an epoxy resin.

Example 3
(Fabrication of FR-4 equivalent substrate)
(1) Preparation of resin varnish: 46.8 parts by weight of a dimethylformamide solvent, 4.1 parts by weight of dicyandiamide as a curing agent, and a high molecular weight naphthalene type epoxy resin as an epoxy resin (EXA-9900, manufactured by Dainippon Ink Industries, Ltd.) 0 parts by weight, 20.0 parts by weight of a low molecular weight naphthalene type epoxy resin (manufactured by Dainippon Ink and Chemicals, HP-4770), 5.0 parts by weight of triphenylphosphine oxide as a curing accelerator, and stirred for 60 minutes, A resin varnish was obtained.
(2) Manufacture of prepreg Using the above-mentioned resin varnish, 100 parts by weight of a 42 μm thick glass fabric (# 1078, manufactured by Nitto Boseki Co., Ltd.) was impregnated with 80 parts by weight of the resin varnish in a solid content. A prepreg having a resin content of 55.2% by weight was produced by drying in a drying furnace at 5 ° C. for 5 minutes.
(3) Manufacture of a laminated board The above-mentioned prepreg was laminated with 12 μm copper foil on both sides and subjected to heat and pressure molding at a pressure of 4 MPa and a temperature of 220 ° C. for 180 minutes to obtain a double-sided copper-clad FR-4 equivalent substrate.
(Production of surface acoustic wave device)
Instead of the double-sided copper-clad FR-5 equivalent substrate of Example 1, a double-sided copper-clad FR-4 equivalent substrate (substrate thickness: 60 μm, each copper foil thickness: 12 μm) was used in the same manner as Example 1. .

Example 4
Example 3 was the same as Example 3 except that dicing was performed so that the side surface of the dam material of the surface acoustic wave device was covered with epoxy resin.

(Comparative Example 1)
In Example 1, instead of a dam material with an adhesive function, as a dam material that does not include a thermosetting resin and does not have an adhesive function, a photosensitive coverlay (manufactured by Hitachi Chemical Co., Ltd .: FR5625 (polyester layer, The photosensitive layer and the polyolefin layer consisted of a three-layer sandwich structure, and the components of the photosensitive layer were made of a mixture such as an acrylic resin.), Except that a film thickness of 25 μm) was used. At this time, in the step of forming the photosensitive cover lay, the photosensitive cover lay is applied to the substrate surface at 80 ° C., 0.4 MPa using a vacuum pressurizing laminator (MVLP-500 / 600IIA, manufactured by Meiki Seisakusho). in laminated, followed by exposure of the pattern 250 mJ / cm ^2, after development, exposing the post UV at 100 mJ / cm ^2, was performed 60 minutes post-cured at 160 ° C., a photosensitive coverlay on the substrate surface Formed.

(Comparative Example 2)
Comparative Example 1 was the same as Comparative Example 1 except that the side surface of the dam material of the surface acoustic wave device was diced so as to be covered with an epoxy resin.

(Comparative Example 3)
Instead of the double-sided copper-clad FR-5 equivalent substrate of Comparative Example 1, a double-sided copper-clad FR-4 equivalent substrate (substrate thickness: 60 μm, each copper foil thickness: 12 μm) was used in the same manner as Comparative Example 1. .

(Comparative Example 4)
Comparative Example 3 was the same as Comparative Example 3 except that the side surface of the dam material of the surface acoustic wave device was diced so as to be covered with an epoxy resin.

  The surface acoustic wave devices obtained in the examples and comparative examples were evaluated as follows. The results are shown in Table 1.

The physical properties of the substrate, dam material and photosensitive coverlay are shown below.
(1) FR-5 equivalent substrate Glass transition temperature (Tg) using DMA: 265 ° C.
Glass transition temperature (Tg) using TMA: 220 ° C
Linear expansion coefficient (CTE) (α1) in the xy plane direction: 11 ppm / ° C.
Linear expansion coefficient (CTE) (α1) in the z direction: 16 ppm / ° C.
(2) FR-4 equivalent substrate Glass transition temperature (Tg) using DMA: 190 ° C.
Glass transition temperature (Tg) using TMA: 175 ° C
Linear expansion coefficient (CTE) (α1) in the xy plane direction: 15 ppm / ° C.
Linear expansion coefficient (CTE) (α1) in the z direction: 45 ppm / ° C.
(3) Dam material (dam material with adhesive function)
Moisture ^{permeability: 16 [g / m 2 ·} 24h]
Elastic modulus at 80 ° C. after exposure: 320 Pa
(4) Photosensitive coverlay (Hitachi Chemical Industry: FR5625)
Elastic modulus at 80 ° C. after exposure: 10000000 Pa

(Elastic modulus)
The dam materials with adhesive function and the photosensitive coverlay obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were exposed to light having a wavelength of 365 nm by irradiation with 700 mJ / cm ² . Next, a dynamic viscoelasticity measuring device Rheo Stress RS150 (manufactured by HAAKE, measurement frequency: 1 Hz, gap interval: 100 μm, measurement temperature range: 25 to 200 ° C., temperature increase rate of 10 ° C./min for the dam material and the photosensitive coverlay ) To measure the storage elastic modulus G ′ and determine the elastic modulus at 80 ° C.

(Glass-transition temperature)
Insulating sheet with copper foil (FR-5 equivalent substrate and FR-4 equivalent substrate) Two resin surfaces are laminated inside, and then heat-pressed for 2 hours at a pressure of 2MPa and a temperature of 200 ° C by vacuum press, The foil was entirely etched to obtain a cured insulating resin. A test piece of 10 mm × 30 mm was cut out from the obtained cured cured resin, heated to 5 ° C./min using DMA (TA Instruments) or TMA (TA Instruments), and tan δ The peak position was defined as the glass transition temperature.

(Linear expansion coefficient)
Insulating sheet with copper foil (FR-5 equivalent substrate and FR-4 equivalent substrate) Two resin surfaces are laminated inside, and then heat-pressed for 1 hour at a pressure of 2 MPa and a temperature of 220 ° C. by vacuum press. The foil was entirely etched to obtain a cured insulating resin. A test piece of 4 mm × 20 mm was cut out from the obtained cured cured resin, and the glass transition temperature, the thickness direction of the substrate, and the linear expansion coefficient in the substrate plane were set to 10 ° C./TMA using TMA (TA Instruments). Measured in minutes.

(TC test method)
In the TC test, 1000 cycles were performed five times using a temperature cycle tester under the conditions of a temperature cycle (−60 ° C. to 150 ° C.), a holding time (10 minutes), and a temperature change time (20 minutes). For example, TSA-71H (Espec Corp.) was used as the temperature cycle tester.
Each code | symbol in Table 1 is as follows.
A: 5 out of 5 passes.
○: 3 times out of 5 passes.
Significant results were shown with the FR-5 equivalent substrates of Examples 1 and 2. This is presumably because solder bump cracks are suppressed and the CTE gap between the FR-5 equivalent substrate and the chip (surface acoustic wave element) is reduced.

(Mold resin penetration observation method)
As the mold resin penetration observation method, an observation method using X-rays using an X-ray apparatus was used.
Each code | symbol in Table 1 is as follows.
○: Yield is 80% or more.
X: The yield is less than 80%.
Significant results were shown with the dam materials of Examples 1 and 3. This is considered that the yield was improved by the dam material being in close contact with the chip.

(PCT test method)
The PCT test method was performed using a PCT chamber under the conditions of 121 ° C. and 100%. this. As the PCT chamber, for example, an EHS-411 series, an EHS-211 series (Espec Corp.), or the like can be used. In this example, the EHS-411 series was used. Further, after 200 hours, the sample was observed with a conventional cross-sectional analysis or a scanning ultrasonic flaw detector (SAT).
Each code | symbol in Table 1 is as follows.
A: 5 out of 5 times, 200h pass.
○: 2 times out of 5 times, 200h pass, 5 times out of 5 times, 50h pass.
X: Total separation at 200h, total separation at 50h.
Significant results were shown with the dam materials of Examples 1-4. This is considered that the airtightness was improved by the dam material being in close contact with the chip.
(Moisture permeability of dam materials)
Using a laminator set at 60 ° C., a dam material was bonded, a film with a film thickness of 100 μm was produced, and an exposure device was used to irradiate light with an exposure amount of 700 mJ / cm ² (wavelength 365 nm). Heat-cured at 180 ° C./2 hours. The obtained cured film was evaluated in an environment of 40 ° C./90% in accordance with a moisture permeable cup method (JIS Z0208) to obtain a moisture permeability.
Each code | symbol in Table 1 is as follows.
○: Moisture permeability is 12 [g / m ² · 24 h] or more.
Significant results were shown with the dam materials of Examples 1-4.

  Examples 1 to 4 showed excellent results in TC test, mold resin penetration, PCT test and moisture permeability.

100 surface acoustic wave device 102 mounting substrate 104 first metal foil 106 second metal foil 110 blind via 111 electroless plating 112 filled via plating 114 filled via 116 second metal film 118 pad 120 first metal layer 122 solder layer 124 Protective sheet 126 First circuit 128 Photosensitive insulating resin layer 130 Ni film 132 Au film 134 Dam material 136 Via 138 Ni plating 140 Solder layer 142 Second circuit 144 Pad 150 Surface acoustic wave element 160 Mold resin 190 Space 200 Elastic surface Substrate for wave element 210 Substrate for surface acoustic wave element

Claims (28)

A mounting board;
A pad provided on the upper surface of the mounting substrate;
A solder layer covering the pad;
A dam material which is provided on the upper surface of the mounting substrate and surrounds the pad in a plan view of the mounting substrate;
A surface acoustic wave device substrate comprising: The dam material is formed by curing an electron beam curable resin composition for a dam material,
The resin composition for dam materials is
The surface acoustic wave element substrate according to claim 1, comprising a thermosetting resin. The resin composition for dam materials is
An alkali-soluble resin;
A photopolymerizable resin;
And further containing 9% by weight or less of an inorganic filler,
The surface acoustic wave device substrate according to claim 2, wherein the photopolymerizable resin includes an acrylic polyfunctional monomer.   4. The surface acoustic wave element substrate according to claim 2, wherein a content of the thermosetting resin is 10% by weight or more and 40% by weight or less of the entire resin composition for a dam material. 5.   The surface acoustic wave device substrate according to claim 3, wherein the photopolymerizable resin includes an epoxy vinyl ester resin.   6. The surface acoustic wave element substrate according to claim 5, wherein a content of the epoxy vinyl ester resin is 3% by weight or more and 30% by weight or less of the entire resin composition for a dam material.   The surface acoustic wave element substrate according to claim 3, wherein the acrylic polyfunctional monomer is a (meth) acrylic acid ester compound.   The surface acoustic wave device substrate according to claim 3, wherein the acrylic polyfunctional monomer is a trifunctional (meth) acrylate compound or a tetrafunctional (meth) acrylate compound.   The substrate for a surface acoustic wave device according to any one of claims 3 to 8, wherein the acrylic polyfunctional monomer is trimethylolpropane tri (meth) acrylate.   The surface acoustic wave device substrate according to any one of claims 3 to 9, wherein the content of the acrylic polyfunctional monomer is 1% by weight or more and 50% by weight or less of the entire resin composition for a dam material.   The surface acoustic wave device substrate according to any one of claims 3 to 10, wherein the alkali-soluble resin is a (meth) acryl-modified novolak resin.   The surface acoustic wave device substrate according to any one of claims 3 to 11, wherein the content of the alkali-soluble resin is 50 wt% or more and 95 wt% or less of the entire resin composition for a dam material. The surface acoustic wave element substrate according to any one of claims 1 to 12, wherein a moisture permeability of the dam material measured by JIS Z0208 B method is 12 [g / m ² · 24h] or more. After exposing all wavelengths of light with a mercury lamp and exposing the accumulated exposure amount to 700 mJ / cm ² with i-line (365 nm) light, the elastic modulus at 80 ° C. of the dam material is 100 Pa or more. The substrate for a surface acoustic wave element according to claim 1, wherein   The elasticity according to any one of claims 1 to 14, wherein the mounting substrate has a linear expansion coefficient (α1) in the xy plane direction of 18 ppm / ° C or less in a region of 25 ° C or more and a glass transition temperature (Tg) or less. Surface wave element substrate.   16. The elasticity according to claim 1, wherein the mounting substrate has a linear expansion coefficient (α1) in the xy plane direction of 11 ppm / ° C. or less in a region of 25 ° C. or more and a glass transition temperature (Tg) or less. Surface wave element substrate.   The elastic surface according to any one of claims 1 to 16, wherein the mounting substrate has a linear expansion coefficient (α1) in the z direction of 55 ppm / ° C or less in a region of 25 ° C or more and a glass transition temperature (Tg) or less. Wave element substrate.   18. The elastic surface according to claim 1, wherein the mounting substrate has a linear expansion coefficient (α1) in the z direction of 16 ppm / ° C. or less in a region of 25 ° C. or more and a glass transition temperature (Tg) or less. Wave element substrate.   The surface acoustic wave device substrate according to claim 1, wherein the glass transition temperature (Tg) of the mounting substrate is 160 ° C. or higher.   The surface acoustic wave device substrate according to any one of claims 1 to 19, wherein the mounting substrate is formed by molding at least one prepreg formed by impregnating a fiber base material with a base resin composition. The base resin composition is
A cyanate resin and / or a prepolymer thereof,
An epoxy resin substantially free of halogen atoms;
An imidazole compound,
An inorganic filler,
The epoxy resin is a mixture of a first epoxy resin and a second epoxy resin having a weight average molecular weight higher than that of the first epoxy resin,
The surface acoustic wave device substrate according to claim 20, wherein the first epoxy resin is an aryl alkylene type epoxy resin, and the weight average molecular weight of the second epoxy resin is 5000 or more.   The surface acoustic wave device substrate according to claim 21, wherein the cyanate resin is a novolac-type cyanate resin.   23. The surface acoustic wave element substrate according to claim 21, wherein the content of the epoxy resin is 5% by weight or more and 60% by weight or less of the whole resin composition for base material.   24. The imidazole compound according to any one of claims 21 to 23, wherein the imidazole compound is an imidazole compound having two or more functional groups selected from an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a hydroxyalkyl group. Surface acoustic wave element substrate.   The surface acoustic wave element substrate according to any one of claims 21 to 24, wherein the content of the inorganic filler is 30 wt% or more and 70 wt% or less of the entire resin composition for a base material. A mounting board;
A surface acoustic wave element disposed opposite to the upper surface of the mounting substrate;
A pad provided on the upper surface of the mounting substrate;
A solder layer covering the pad;
A dam material provided on the upper surface of the mounting substrate and surrounding the pad in a plan view of the mounting substrate;
The surface acoustic wave device substrate according to claim 1, comprising the mounting substrate, the pad, the solder layer, and the dam material.
The dam material is provided between the mounting substrate and the surface acoustic wave element,
The surface acoustic wave device in which the pad and the solder layer connect the mounting substrate and the surface acoustic wave element.   27. The surface acoustic wave device according to claim 26, wherein a sealing material is formed on at least an upper surface of the surface acoustic wave element.   The surface acoustic wave device according to claim 26 or 27, wherein a side surface of the dam material is exposed.

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