JP6538379B2 - Piezoelectric device and method of manufacturing the same - Google Patents

Description

  The present invention relates to a piezoelectric device, and more particularly to a piezoelectric device such as a surface acoustic wave (SAW) device or an oscillator suitable for high-density mounting equipment such as a cellular phone and a method of manufacturing the same.

  The structure of this type of piezoelectric device will be described by taking a SAW device as an example. In the SAW device, it is necessary to secure in the package an operation space (also referred to as a hollow portion or a cavity) in which the electrode vibrates by the piezoelectric effect. In the SAW device, it is essential to secure a predetermined cavity around the comb electrode portion (IDT electrode portion). In addition, it is necessary to secure the working space of the crystal piece similarly for a piezoelectric device such as a vibrator or an oscillator using the crystal piece or the like. In the following, although a SAW device is described as an example, the present invention can be applied to other piezoelectric devices such as a quartz oscillator and a MEMS resonator.

  Conventional SAW devices are flip chip bonded (face-down bonding) to the wiring substrate using gold (Au) bumps or solder bumps to make the size and height of the SAW device smaller, and resin, etc. The entire SAW element chip is sealed to constitute a small package device of the SAW device.

  Furthermore, in the SAW device, a predetermined hollow portion is formed around the comb-tooth electrode portion which is a main operation portion, and while holding the hollow portion, a collective piezoelectric substrate on the comb-tooth electrode side (a wafer on which a plurality of chips are formed) A microminiaturized chip-sized package SAW device is proposed in which the whole is sealed with a resin and an external connection electrode is formed and then divided into individual SAW devices by dicing.

  For example, in the SAW device described in Patent Document 1, a void (hollow portion) forming layer (outer wall) made of photosensitive resin is formed on the upper surface of a SAW chip (piezoelectric substrate) on which a comb electrode is formed. A sealing layer (ceiling part) is laminated and sealed on the void forming layer, and a void (hollow part) is formed around the comb electrode.

  Further, in the SAW device described in Patent Document 2, a cover having a through electrode facing the SAW chip (piezoelectric substrate) on which a comb electrode is formed is joined and sealed via a metal bonding portion. And a hollow portion for accommodating the comb electrode between the SAW chip and the cover.

  Furthermore, in the SAW device described in Patent Document 3, a SAW element which is a main operation layer portion provided on the surface of a piezoelectric substrate, a first resin portion having a hollow portion on the SAW element, and the first resin A second resin part is provided on the second part, and a silica filler is added to the second resin part to increase the elastic modulus of the second resin part (ceiling part), thereby making it difficult to bend and improve the mechanical strength. . Moreover, in patent document 4, the resin board which mixed mica which is an inorganic material as a filler is used for the ceiling layer which seals the hollow part which accommodated the SAW element.

  FIG. 35 is a cross-sectional view for explaining a structural example of a wafer level chip scale (size) package type SAW device. FIG. 36 is an explanatory view of a state in which the SAW device shown in FIG. 35 is surface mounted on a mounting substrate. A comb electrode 2 is formed on the main surface of the piezoelectric substrate 1, and an outer wall layer 6 made of a resin is surrounded around the comb electrode 2 to form a hollow portion (chamber). The opening of the hollow portion is covered and sealed by a ceiling plate 7.

  The outer wall layer 6 is provided with a plurality of openings, and electrode posts 4 are formed in the openings by plating. The roots of the electrode columns 4 are electrically connected to the lead wires 3 of the comb electrode 2. A mounting terminal (solder ball or solder bump or the like) 5 is formed on the top of the electrode column 4. The mounting terminals 5 are provided such that the tops thereof are higher than the ceiling plate 7 forming the hollow portion.

The mounting terminals 5 are formed by printing solder bumps on the electrode columns 4 formed by electrolytic plating of Cu and electroless plating of Au / Ni. The mounting of the SAW device on the mounting substrate shown in FIG. 35 is carried out using the mounting terminals 5 as shown in FIG. The mounting terminal 5 is connected to the terminal pad of the wiring pattern provided on the mounting substrate 8 for mounting. Thus, formation of the mounting terminal 5 requires a plurality of steps.

  FIG. 37 is a plan view of relevant parts for explaining problems in the ceiling plate for sealing the hollow portion for housing the comb-tooth electrode. FIG. 37 (a) shows a state in which a heat resistant resin plate 7 'is attached to cover a quartz wafer on which a plurality of SAW devices are formed. Reference numeral 26 denotes a cut line for separating into pieces in the final step. FIG. 37 (b) is an enlarged view of one SAW device corresponding to FIG. 37 (a). A photosensitive binder is mixed in the heat resistant resin plate 7 '. As the heat-resistant resin plate 7 ', a polyimide-based thermosetting resin plate having low gas property is suitable, but a heat-resistant resin material having other similar characteristics can also be used.

  In the heat-resistant resin plate material 7 'of FIG. 37 (a), light-transmissive mica is suitably used as a filler in order to improve the mechanical strength for holding the hollow portion accommodating the comb teeth with little deflection. The amount of is mixed. An exposure mask is placed on the top of the heat-resistant resin plate material 7 ′ attached to cover the wafer, and a technique using a photolithographic process of irradiating with actinic radiation suitable for ultraviolet light and developing is performed, as shown in FIG. As shown, an opening 4 'for providing an electrode post 4 (see FIG. 36) is formed.

  However, in the photolithography process described above, unevenness in the light transmission amount occurs due to the uneven shape and uneven distribution of the filler mixed in the resin plate, the opening pattern of the exposure mask is not accurately transferred, and the filler from the opening wall The residue of H may protrude to form an opening having an irregular edge as shown in FIG. 24 (b). In such a case, the electrode pillars and the plating pattern can not be formed correctly.

  FIG. 38 is a process diagram for explaining an example of a manufacturing process of a substrate built-in component for mounting an electronic component in a substrate. In response to the demand for downsizing and thinning of electronic devices such as portable terminals, a method has been developed in which electronic components are embedded and integrated in a mounting substrate. In FIG. 38, a recessed portion for embedding is formed in the component embedded substrate 20 in which the electronic component is embedded and mounted (a). The electronic component 21 is accommodated in the recess with the component terminal 22 directed to the open end of the recess (FIG. B). Then, the resin 23 is poured into the recess to embed the electronic component 21 (c). An opening 24 reaching the component terminal 22 is opened at the position of the component terminal 22 (d). Electrodes 25 are formed by applying electric Cu plating to the openings 24 (e).

  In this method, the connection with the mounting terminal of the component is made by Cu electroplating, but since the compatibility with the solder is poor, the solder bump can not be used. In addition, since it is difficult to change the arrangement of the mounting terminals in the current structure, it is not suitable for use as a component built-in component.

Unexamined-Japanese-Patent No. 2006-108993 Unexamined-Japanese-Patent No. 2006-197554 JP 2007-142770 A JP, 2011-147098, A

  As described above, the mounting terminal having the structure described with reference to FIG. Further, as described in FIG. 37, in the case of using the resin plate containing the filler mixed as the ceiling plate and forming the opening for the component terminal in the photolithography process, the opening is not accurately patterned, as shown in FIG. In such a terminal structure, it is difficult to change the position of the component terminal. Therefore, it may not meet the customer's request.

  When a piezoelectric component of this type is mounted on a mounting substrate or the like by a transfer mold or the like at a customer and used in a module or the like, a pressure of 5 MPa to 15 MPa is usually applied to the piezoelectric component. When the void (hollow portion) forming layer and the sealing layer of the SAW device described in the above are made of only an organic material, the resin layer constituting the ceiling plate must be thickened or made of a hard material When resin sealing is performed by transfer molding or the like, there is a possibility that the hollow portion for housing the comb-like electrode is crushed and the electrical characteristics of the comb-like electrode are impaired. Therefore, as described in FIG. 37, the resin is mixed with an inorganic filler (inorganic filler) such as mica to increase the mechanical strength.

  In the SAW device as described in Patent Document 2, the formation of the through electrode on the cover, and the bonding and bonding of the SAW chip (piezoelectric substrate on which the comb electrode is formed) and the cover (terminal side piezoelectric substrate, ceiling plate) For this purpose, an electrode is separately required, and at the time of bonding of the substrates, "warpage" occurs in the substrate, and the airtightness of the hollow portion (chamber) accommodating the comb electrode may be reduced. Furthermore, since substrates (wafers) made of the same material (piezoelectric substrate) are bonded to each other, the manufacturing cost of the piezoelectric component may be increased. Furthermore, although thinning of the substrate (wafer) is indispensable in order to realize a reduction in height of the piezoelectric component, its realization has been extremely difficult.

Furthermore, in the SAW device described in Patent Document 3, the filler of silica is added to the photosensitive resin constituting the second resin portion (the ceiling portion) to improve the elastic modulus. However, since the average size of the filler to be added is as large as 0.01 μm to 8 μm, a sufficient mold pressure resistance effect can not be obtained. In the SAW device disclosed in Patent Document 4 using mica as the filler, when the photolithography process is used, there is a possibility that patterning may be inaccurate due to uneven exposure due to the filler of mica mixed .

  The present invention is to provide a novel structure of a piezoelectric device and a method of manufacturing the same for solving various problems including the problems described above. The representative configuration is described as follows. In order to facilitate understanding of the invention, reference numerals of corresponding embodiments are appended.

(1) The piezoelectric device according to the present invention is connected to the piezoelectric substrate 1, the comb electrode 2 formed on the main surface of the piezoelectric substrate, and the comb electrode and extended to the outer edge of the piezoelectric substrate 1 An outer wall layer 6 disposed around the outer periphery of the piezoelectric substrate including the lead wire 3 and the lead wire to form a hollow portion serving as an operation space of the comb electrode; and a bridge to the outer wall layer And a ceiling plate 7 which is entangled to seal the hollow portion,
The ceiling plate 7 is made of a heat-resistant resin whose mechanical strength is improved by mixing a filler of an inorganic material,
The lead-out wires 3 are respectively formed on a pair of opposing side surfaces of the outer wall layer,
The piezoelectric substrate connected to an upper surface connected to a pair of opposite side surfaces of the outer wall layer and a pair of opposite side surfaces of the outer wall layer of the ceiling plate and a pair of opposite side surfaces of the outer wall layer of the piezoelectric substrate A metal plating layer 10 'insulated in a plurality of sections across the outer edge of the
The metal plating layer 10 ′ is electrically connected to the lead-out wiring 3 at the outer edge of the piezoelectric substrate 1;
The upper surface of the ceiling plate of the metal plating layer is a mounting terminal 11, and the side surface of the outer wall layer of the metal plating layer is a side wiring 10 connecting the lead wiring and the mounting terminal ,
An inclined surface which curves gradually gradually from the ceiling plate to the outer wall layer 6 on the side surfaces connected to the pair of opposite side surfaces of the outer wall layer 6 and the pair of opposite side surfaces of the outer wall layer of the ceiling plate wherein the chromatic allowed.

(2) Further, the piezoelectric device according to the present invention is connected to the piezoelectric substrate 1, the comb electrode 2 formed on the main surface of the piezoelectric substrate, and the comb electrode and extends to the outer edge of the piezoelectric substrate 1. An outer wall layer 6 provided around the outer periphery of the piezoelectric substrate including the lead wire 3 and including the lead wire to form a hollow portion serving as an operation space of the comb electrode; and the outer wall layer And a ceiling plate 7 for sealing the hollow portion by bridging the
The ceiling plate 7 is made of a heat-resistant resin whose mechanical strength is improved by mixing a filler of an inorganic material,
The lead-out wires 3 are respectively formed on a pair of opposing side surfaces of the outer wall layer,
The piezoelectric substrate connected to an upper surface connected to a pair of opposite side surfaces of the outer wall layer and a pair of opposite side surfaces of the outer wall layer of the ceiling plate and a pair of opposite side surfaces of the outer wall layer of the piezoelectric substrate A metal plating layer 10 'insulated in a plurality of sections across the outer edge of the
The metal plating layer 10 ′ is electrically connected to the lead-out wiring 3 at the outer edge of the piezoelectric substrate 1;
The upper surface of the ceiling plate of the metal plating layer is a mounting terminal 11, and the side surface of the outer wall layer of the metal plating layer is a side wiring 10 connecting the lead wiring and the mounting terminal ,
A solder flow prevention layer 31 is provided on the side surface extending to the metal plating layer 10 ′ provided on the outer edge of the piezoelectric substrate 1 including the periphery of the mounting terminal 11 provided on the ceiling plate 7 .

( 3 ) Further, in the present invention, the solder flow preventing layer 31 described in the above (2) is provided on the entire surface of the ceiling plate 7 and the side surface except the barrier metal which is a part of the mounting terminal 11 or the terminal window. It is characterized by

( 4 ) Further, the present invention is characterized in that the solder flow prevention layer 31 described in the above ( 2 ) is provided independently for each of the mounting terminals 11.

(5) Further, the present invention is characterized in that allowed have a barrier metal layer on the mounting terminal 11 according to (2).

( 6 ) In the method of manufacturing a piezoelectric device according to the present invention, the main surface of the piezoelectric wafer constituting the piezoelectric substrate 1 is connected to the comb electrode 2 and the comb electrode and extended to the outer edge of the piezoelectric substrate. An electrode forming step of forming the wiring 3 on a pair of opposing side surfaces of the piezoelectric substrate 1;
An operation space forming step of setting an outer wall layer 6 for forming a hollow portion to be an operation space of the comb electrode, around the outer periphery of the piezoelectric substrate including the lead-out wiring;
A ceiling plate setting step of sealing the hollow portion by bridging the periphery of a ceiling plate made of a heat-resistant resin plate mixed with an inorganic filler to the outer wall layer 6;
A ceiling plate patterning step of separating the ceiling plate 7 into patterns of individual SAW devices;
The piezoelectric substrate connected to an upper surface connected to a pair of opposite side surfaces of the outer wall layer and a pair of opposite side surfaces of the outer wall layer of the ceiling plate and a pair of opposite side surfaces of the outer wall layer of the piezoelectric substrate Forming a metal plating layer 10 'in a plurality of sections across the outer edge of
A singulation step of dividing the bonded piezoelectric wafer and the ceiling plate into individual SAW devices after each of the above steps;
Including
The upper surface of the ceiling plate of the metal plating layer is used as the mounting terminal 11, and the outer surface of the metal plating layer is electrically connected to the lead wiring 3 at the outer edge of the piezoelectric substrate 1 by the metal plating layer 10 '. The side surface of the enclosure layer is a side wiring 10 connecting the lead wiring and the mounting terminal ,
As the ceiling plate patterning process, a cutting method using a dicing blade with a tapered angle is used .

( 7 ) Further , in the method of manufacturing a piezoelectric device according to the present invention, the comb electrode 2 and the comb electrode are connected to the main surface of the piezoelectric wafer constituting the piezoelectric substrate 1 and extended to the outer edge of the piezoelectric substrate. An electrode forming step of forming a lead wire 3 to be formed on a pair of opposing side surfaces of the piezoelectric substrate 1;
An operation space forming step of setting an outer wall layer 6 for forming a hollow portion to be an operation space of the comb electrode, around the outer periphery of the piezoelectric substrate including the lead-out wiring;
A ceiling plate setting step of sealing the hollow portion by bridging the periphery of a ceiling plate made of a heat-resistant resin plate mixed with an inorganic filler to the outer wall layer 6;
A ceiling plate patterning step of separating the ceiling plate 7 into patterns of individual SAW devices;
The piezoelectric substrate connected to an upper surface connected to a pair of opposite side surfaces of the outer wall layer and a pair of opposite side surfaces of the outer wall layer of the ceiling plate and a pair of opposite side surfaces of the outer wall layer of the piezoelectric substrate Forming a metal plating layer 10 'in a plurality of sections across the outer edge of
A singulation step of dividing the bonded piezoelectric wafer and the ceiling plate into individual SAW devices after each of the above steps;
Including
The upper surface of the ceiling plate of the metal plating layer is used as the mounting terminal 11, and the outer surface of the metal plating layer is electrically connected to the lead wiring 3 at the outer edge of the piezoelectric substrate 1 by the metal plating layer 10 '. The side surface of the enclosure layer is a side wiring 10 connecting the lead wiring and the mounting terminal ,
After the metal plating layer forming step of forming the metal plating layer 10 ′, it is provided on the upper surface of the ceiling plate 7 avoiding the barrier metal or terminal window which is a part of the mounting terminal 11 and the outer edge of the piezoelectric substrate 1 A solder flow preventing layer forming step of forming a solder flow preventing layer 31 on the side surface leading to the metal plating layer 10 ′ is characterized.

( 8 ) Further, in the method of manufacturing a piezoelectric device according to the present invention, the ceiling plate 7 excluding the solder metal or the terminal window which is a part of the mounting terminal 11 is the solder flow prevention layer 31 described in the above ( 7 ). And it provided in the whole surface of the said side, It is characterized by the above-mentioned.

( 9 ) Further, the method of manufacturing a piezoelectric device according to the present invention is characterized in that the solder flow prevention layer 31 described in the above ( 7 ) is provided independently for each of the mounting terminals 11.

( 10 ) Further, the method of manufacturing a piezoelectric device according to the present invention is characterized by including a barrier metal layer forming step of forming a barrier metal layer on the mounting terminal 11 described in ( 7 ).

( 11 ) The present invention is not limited to the above configuration, and various modifications can be made without departing from the technical concept of the present invention.

  According to the above-described piezoelectric device and the method of manufacturing the same of the present invention, mounting terminals (component terminals of the present device) can be formed at desired positions in a simple process, and a substrate with electrode columns, solder balls or bumps as in the prior art. Since there is no need to set the surface height, the piezoelectric device can be obtained at low cost.

  Further, when using as a component with a built-in substrate as described in FIG. 38, since the mounting terminal does not require a solder ball or a solder bump, connection by Cu plating becomes possible.

  Furthermore, since the mounting terminals are formed on the resin portion that constitutes the ceiling layer having a large area, the positions of the mounting terminals can be arbitrarily selected, so the mounting terminals can be arranged at the places desired by the customer.

  Furthermore, by forming a wire (side wire) connecting the comb electrode portion and the mounting terminal to the side wall portion of the piezoelectric device, the sealing structure of the joint portion between the outer wall layer and the ceiling layer is surely strengthened. Therefore, the airtightness of the hollow portion is improved.

  And since the patterning process which forms the opening for mounting electrode formation in a ceiling layer is not required, the manufacturing process can be greatly simplified. In addition, mechanical processing using a dicing blade or the like can also be used to process the ceiling layer. By employing mechanical processing, it is possible to avoid the occurrence of an irregular opening shape due to the filler residue as described in FIG.

  Then, by providing a solder flow prevention layer, the mounting terminals and terminal pads are caused by the wraparound of the solder to the side wiring portion when mounting faces down on the terminal pads provided on the surface of the mounting substrate using solder balls or the like. It is possible to prevent a reduction in the amount of solder interposed therebetween, and to prevent defective soldering and destabilization of the gap with the mounting substrate.

  Further, by providing a crushing prevention layer on the upper surface of the ceiling plate, crushing of the hollow portion accommodating the comb-shaped electrode is prevented by pressurization in the manufacturing process of the piezoelectric device and pressurization in the mounting process on the substrate. . Furthermore, the improvement of mold resistance at the time of modularizing a piezoelectric device can also be expected.

  As described above, according to the present invention, a piezoelectric device extremely excellent in mold pressure resistance, reduced in height and reduced in size can be freely arranged in mounting terminals without increasing the thickness of parts. Can be manufactured at low cost. As described above, the present invention is not limited to the SAW device, and can be applied to a piezoelectric device such as a quartz oscillator, and a similar piezoelectric device such as a MEMS resonator.

It is sectional drawing explaining the structure of Example 1 which applied the piezoelectric device concerning this invention to a SAW device. It is a top view of Example 1 which applied the piezoelectric device concerning the present invention shown by the sectional view of Drawing 1 to a SAW device. FIG. 7 is a main process chart illustrating the method for manufacturing the SAW device in Example 1 to which the piezoelectric device of the present invention is applied. It is a flowchart following FIG. 3 explaining the manufacturing method of Example 1 of the SAW device to which the piezoelectric device of this invention is applied. FIG. 5 is a process diagram following FIG. 4 for explaining the method of manufacturing the SAW device in Example 1 to which the piezoelectric device of the present invention is applied. It is process drawing following FIG. 5 explaining the manufacturing method of Example 1 of the SAW device to which the piezoelectric device of this invention is applied. FIG. 7 is a process diagram following FIG. 6 for explaining the method of manufacturing the SAW device in Example 1 to which the piezoelectric device of the present invention is applied. It is a flowchart following FIG. 7 explaining the manufacturing method of Example 1 of the SAW device to which the piezoelectric device of this invention is applied. It is a flowchart following FIG. 8 explaining the manufacturing method of Example 1 of the SAW device to which the piezoelectric device of this invention is applied. FIG. 10 is a process diagram following FIG. 9 for explaining the method for manufacturing the SAW device in Example 1 to which the piezoelectric device of the present invention is applied. It is sectional drawing explaining the structure of Example 2 which applied the piezoelectric device concerning this invention to a SAW device. FIG. 12 is a top view of Example 2 in which the piezoelectric device according to the present invention shown in the cross-sectional view of FIG. 11 is applied to a SAW device. It is a main process drawing explaining the manufacturing method of the SAW device concerning Example 2 of the present invention. It is a flowchart following FIG. 13 explaining the manufacturing method of Example 2 of the SAW device to which the piezoelectric device of this invention is applied. It is a flowchart following FIG. 14 explaining the manufacturing method of Example 2 of the SAW device to which the piezoelectric device of this invention is applied. It is a flowchart following FIG. 15 explaining the manufacturing method of Example 2 of the SAW device to which the piezoelectric device of this invention is applied. FIG. 17 is a process diagram following FIG. 16 for explaining the method for manufacturing the SAW device in Example 2 to which the piezoelectric device of the present invention is applied. FIG. 18 is a process diagram following FIG. 17 for explaining the method for manufacturing the SAW device in Example 2 to which the piezoelectric device of the present invention is applied. FIG. 19 is a process diagram following FIG. 18 for explaining the method for manufacturing the SAW device in Example 2 to which the piezoelectric device of the present invention is applied. FIG. 20 is a process diagram following FIG. 19 for explaining the method for manufacturing the SAW device in Example 2 to which the piezoelectric device of the present invention is applied. FIG. 21 is a process diagram following FIG. 20 for explaining the method for manufacturing the SAW device in Example 2 to which the piezoelectric device of the present invention is applied. FIG. 12 is an explanatory view of a state in which the SAW device shown in FIG. 11 is mounted on terminal pads of a mounting substrate by soldering. It is an explanatory view of a state where solder between mounting terminal and terminal pad got wet to side wiring by solder flow. FIG. 26 is a cross-sectional view along line XX in FIG. 25 for explaining a third example of the SAW device to which the piezoelectric device of the present invention is applied. It is a top view explaining Example 3 of a SAW device to which a piezoelectric device of the present invention is applied. FIG. 28 is a cross-sectional view taken along the line X-X of FIG. 27 for explaining a state in which the solder balls of Example 3 of the SAW device to which the piezoelectric device of the present invention is applied is provided. It is a top view explaining Example 3 of a SAW device to which a piezoelectric device of the present invention is applied. FIG. 30 is a cross-sectional view along line XX in FIG. 29 for explaining a SAW device according to a fourth embodiment to which the piezoelectric device of the present invention is applied. It is a top view explaining Example 4 of the SAW device to which the piezoelectric device of the present invention is applied. It is process drawing explaining the principal part of the manufacturing method of the SAW device to which Example 3 of the SAW device to which the piezoelectric device of the present invention is applied is applied. FIG. 33 is a cross-sectional view along the line XX in FIG. 32 for explaining the main part of a fifth example of the SAW device to which the piezoelectric device of the present invention is applied. It is a top view explaining an important section of Example 5 of a SAW device to which a piezoelectric device of the present invention is applied. It is sectional drawing in alignment with XX of FIG. 34 explaining Example 5 of the SAW device to which the piezoelectric device of this invention is applied. It is a top view explaining Example 5 of the SAW device to which the piezoelectric device of the present invention is applied. It is sectional drawing explaining the constructional example of a wafer level chip scale (size) package type SAW device. FIG. 36 is an explanatory view of a state in which the SAW device shown in FIG. 35 is surface mounted on a mounting substrate. It is a principal part top view explaining the problem of the ceiling board which seals the hollow part which accommodates a comb-tooth electrode. It is a process drawing explaining an example of a manufacturing process of a substrate built-in part which mounts electronic parts in a substrate.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the attached drawings.

  FIG. 1 is a cross-sectional view for explaining the structure of Example 1 in which a piezoelectric device according to the present invention is applied to a SAW device. FIG. 2 is a top view of Example 1 in which the piezoelectric device according to the present invention shown in the cross-sectional view of FIG. 1 is applied to a SAW device. The SAW device according to the first embodiment uses lithium tantalate as the piezoelectric substrate 1 and is connected to the comb electrode (IDT) 2 and the comb electrode 2 on the main surface of the piezoelectric substrate 1 and the outer edge of the piezoelectric substrate And an extension wire 3 extended to the Although a quartz plate or lithium niobate can also be used for the piezoelectric substrate 1, it will be described here that lithium tantalate is used. An outer wall layer 6 is formed around the outer periphery of the piezoelectric substrate including the lead-out wiring 3 to form a hollow portion to be an operation space of the comb electrode 2. The ceiling plate 7 is fixed by bridging the end periphery to the outer wall layer 6 to seal the hollow portion (chamber) which is to be the operation space of the comb electrode 2. The ceiling plate 7 is made of a heat-resistant resin in which a mechanical strength is improved by mixing a filler of an inorganic material. In this example, white mica was used as a filler.

  As shown in FIGS. 1 and 2, in the SAW device of this embodiment, the lead-out wiring 3 of the comb-tooth electrode 2 is a pair of opposing side surfaces of the outer wall layer 6 (right and left in FIG. 3) are formed on each side. As shown in FIG. 1, in the SAW device of the present embodiment, the ceiling plate 7 is provided on the side surface connected to the pair of opposite side surfaces of the outer wall layer 6 and the pair of opposite side surfaces of the outer wall layer 6 of the ceiling plate 7. And the outer wall layer 6 gradually slopes. Then, an upper surface connected to the pair of side surfaces facing the left and right of the outer wall layer 6 and a pair of opposite side surfaces of the outer wall layer 6 of the ceiling plate 7 and a pair of opposite side surfaces facing the outer wall layer 6 of the piezoelectric substrate 1 A metal plating layer formed to be insulated in a plurality of sections is formed over the outer edge of the piezoelectric substrate 1 connected to.

  The metal plating layer is electrically connected to the lead wiring 3 at the outer edge of the piezoelectric substrate 1, the upper surface of the ceiling plate 7 of the metal plating layer is the mounting terminal 11, and the side surface of the outer wall layer of the metal plating layer is lead wiring 3 And the side terminals 10 for connecting the mounting terminals 11. With this structure, it is not necessary to set the height with respect to the substrate surface with the electrode column, the solder ball or the solder bump as shown in FIG. 35 for the mounting terminal 11, so that the SAW device can be obtained at low cost. Further, since solder balls and solder bumps are not used for the mounting terminals, connection by Cu plating becomes possible when used as a component with a built-in substrate as described in FIG.

  Further, according to the present embodiment, since the mounting terminals are formed on the resin portion constituting the ceiling layer 7 having a large area, the positions of the mounting terminals can be arbitrarily selected. Therefore, the mounting terminals are arranged at the places desired by the customers. be able to.

  Further, according to the present embodiment, by forming the wiring (side wiring) 10 connecting the comb electrode portion and the mounting terminal to the side wall portion of the SAW device, sealing of the joint portion of the outer wall layer 6 and the ceiling layer 7 The structure is reliable, and the airtightness of the hollow portion can be improved.

  As described above, according to the present embodiment, the SAW device extremely excellent in mold pressure resistance and reduced in height and size can be used for arranging the mounting terminals without increasing the thickness of parts. SAW devices with a degree of freedom can be manufactured at low cost.

  Next, a method of manufacturing the SAW device of the first embodiment will be described with reference to FIGS. 3 to 10. A comb electrode (IDT electrode) 2 on the main surface of a lithium tantalate wafer (piezoelectric wafer) 1 which is a piezoelectric substrate, and a pair of lead wires 3 connected to the comb electrode 2 and extended to the outer edge of the piezoelectric wafer Are formed on the opposite side surfaces of the envelope layer 6 respectively. The comb-tooth electrode 2 and the lead-out wiring 3 contain any one of Al, Cu, Au, Cr, Ru, Ni, Mg, Ti, W, V, Ta, Mo, Ag, In, and Sn as a main component. These materials, or compounds of these materials with oxygen, nitrogen, silicon, or alloys of these materials, or intermetallic compounds, are formed by patterning of thin films formed by laminating these in multiple layers.

  Next, the outer wall layer 6 is formed around the outer periphery of the piezoelectric substrate 1 including the extended portion of the lead-out wiring 3 to form a hollow portion to be an operation space of the comb electrode 2. The outer wall layer 6 is formed by application of a photosensitive heat-resistant resin, which is preferably made of polyimide or epoxy resin, and a photolithographic process using an exposure mask. It is desirable to mix an inorganic filler suitable for white mica into the resin constituting the outer wall layer 6 to improve the elastic modulus and to increase the mechanical strength.

  A heat-resistant resin plate suitable for covering the outer wall layer 6 and using a polyimide or an epoxy resin mixed with the same inorganic filler as described above is fixed to be a component of the ceiling plate 7. The constituent material of the ceiling plate 7 seals the hollow portion that bridges the periphery to the outer wall layer 6 surrounding each of the comb-like electrodes 2 to secure the working space of the comb-like electrodes 2. ... Figure 3

  Next, the components of the ceiling plate 7 are separated into patterns for each individual SAW device. In this embodiment, a cutting method using a dicing blade 12 with a tapered angle of curved surface as shown in FIG. 4 is used to separate the pieces. By using the dicing blade 12 having such a taper angle, in the state of being separated into individual ceiling boards 7 in a piece-by-piece manner, the outer enclosure walls of the pair of opposing side walls of the enclosure wall layer 6 and the ceiling board 7 On the side surface connected to the pair of opposing side surfaces of the layer 6, a gradually curved inclined surface is formed from the ceiling plate 7 to the outer wall layer 6. ... Figure 4

  After separating the components of the ceiling plate 7 into patterns of individual SAW devices, a drawing between the gradually curved inclined surface from the ceiling plate 7 to the outer wall layer 6 and the adjacent SAW devices A metal film is deposited to cover the line 3. This metal film becomes a seed layer 15 for formation of side wiring and mounting terminals using electrolytic plating in a later step.

  The type of the seed layer 15 is not particularly limited as long as it is a metal to which plating is attached, such as Cu or Au. In this example, Cu was formed to a thickness of 4000 Å on a 200 Å-thick film of Ti. When a resin such as polyimide is used as the ceiling layer 7, adhesion to metal is poor. Therefore, by performing plasma treatment or blasting on the resin surface as pretreatment, adhesion is improved by performing surface roughening treatment. It can be improved. According to experiments, it has been confirmed that when a polyimide resin is roughened to a surface roughness Ra of 0.3 to 0.5 μm by blasting, a metal film with good adhesion can be obtained. ... Figure 5

  Note that in FIG. 5 and thereafter, only the portions of two adjacent SAW devices are enlarged and displayed, and the left and right portions of the figure are simplified. A photosensitive resist is applied on the seed layer 15 shown in FIG. 5, and the seed layer 15 in the portion to be plated with the side wiring and the mounting terminal is exposed in a photolithography process using an exposure mask. A resist 16 is left in the portion where plating is unnecessary. ... Figure 6

  Exposed in a plurality of sections (see FIG. 2) across the outer edge of the piezoelectric substrate 1 connected to the pair of opposing side surfaces of the outer wall layer 6 and the opposite surface of the outer wall layer 6 of the ceiling plate 7 using a resist pattern. On the seed layer 15, the metal plating layer 10 'is grown. As the metal to be plated, Ni, Au, Cu or the like is used. In this embodiment, Cu was formed to a thickness of about 10 μm by copper sulfate plating. If necessary, a solder bump may be formed on the portion to be the mounting terminal of the plated layer 10 ′ using a method such as printing. ... FIG. 7

  Although the process described in FIGS. 5 to 7 is a method of forming the plated layer 10 'to be the mounting terminals 11 and the side wiring 10 using electrolytic plating, the plated layer 10' is formed by electroless plating. It can also be done. In the case of employing the electroless plating, for example, at the time of film formation of the seed layer by sputtering, sputtering film formation may be selectively performed on a portion where the plating layer 10 'is formed using a metal mask.

  After the plating layer 10 'is formed, the resist 16 is dissolved and removed with a solution such as acetone. The seed layer 15 is exposed in the portion where the resist is removed. ... Figure 8

  The etching solution is used to etch and remove the seed layer 15 exposed on the surface of the top plate 7, the envelope layer 6, and the surface of the piezoelectric substrate 1. ... Figure 9

  After each process described above, the piezoelectric substrate 1 is cut by dicing at the boundaries of the individual SAW devices to be separated into individual SAW devices. The separated individual SAW devices are as shown in FIG. 1 and FIG. ... FIG. 10

  Then, the upper surface of the ceiling plate 7 of the metal plating layer electrically connected to the lead wiring 3 at the outer edge of the piezoelectric substrate 1 by the metal plating layer 10 ′ is taken as a mounting terminal (component terminal) 11. Since the lead-out wiring 3 and the mounting terminal 11 are connected by the side wiring 10 passing through the side surface of the outer wall layer 6, opening processing of the outer wall layer and opening processing of the ceiling plate are required as described in the prior art. Therefore, the SAW device can be manufactured at low cost.

  As described above, in the SAW device manufactured by the manufacturing method according to the present embodiment, since the mounting terminal is formed on the resin portion forming the ceiling layer having a large area, the position of the mounting terminal can be arbitrarily selected, and the customer desires The mounting terminals can be arranged in places. In addition, by forming a wire (side wire) connecting the comb electrode portion and the mounting terminal on the side wall portion of the SAW device, the sealing structure of the bonding portion between the outer wall layer and the ceiling layer becomes reliable, and the hollow portion is airtight. Improve.

  FIG. 11 is a cross-sectional view for explaining the structure of Example 2 in which the piezoelectric device according to the present invention is applied to a SAW device. FIG. 12 is a top view of Example 2 in which the piezoelectric device according to the present invention shown in the cross-sectional view of FIG. 11 is applied to a SAW device. FIG. 11 corresponds to a cross section taken along line X-X of FIG. In the SAW device according to the second embodiment, as in the first embodiment, lithium tantalate is used as the piezoelectric substrate 1, and the comb electrode 2 and the comb electrode 2 are connected to the main surface of the piezoelectric substrate 1. It has a lead wire 3 extended to the outer edge of the piezoelectric substrate. Although a quartz plate or lithium niobate can also be used for the piezoelectric substrate 1, it will be described here that lithium tantalate is used. An outer wall layer 6 is formed around the outer periphery of the piezoelectric substrate including the lead-out wiring 3 to form a hollow portion to be an operation space of the comb electrode 2. The ceiling plate 7 is fixed by bridging the end periphery to the outer wall layer 6 to seal the hollow portion serving as the working space of the comb electrode 2. The ceiling plate 7 is made of a heat-resistant resin in which a mechanical strength is improved by mixing a filler of an inorganic material. In this example, white mica was used as a filler.

  As shown in FIGS. 11 and 12, in the SAW device of the present embodiment, the lead-out wiring 3 of the comb-tooth electrode is a pair of opposing side surfaces of the outer wall layer 6 (left and right sides in FIG. 3) are formed in each. As shown in FIG. 11, in the SAW device of the present embodiment, the ceiling plate 7 is provided on the side surface connected to the pair of opposite side surfaces of the outer wall layer 6 and the pair of opposite side surfaces of the outer wall layer 6 of the ceiling plate 7. The step surface which becomes a step from the side surface of the outer wall layer 6 to the outer wall layer 6 is provided. Then, an upper surface connected to the pair of side surfaces facing the left and right of the outer wall layer 6 and a pair of opposite side surfaces of the outer wall layer 6 of the ceiling plate 7 and a pair of opposite side surfaces facing the outer wall layer 6 of the piezoelectric substrate 1 A metal plating layer formed to be insulated in a plurality of sections is formed over the outer edge of the piezoelectric substrate 1 connected to.

  The metal plating layer is electrically connected to the lead wiring 3 at the outer edge of the piezoelectric substrate 1, the upper surface of the ceiling plate 7 of the metal plating layer is the mounting terminal 11, and the side surface of the outer wall layer of the metal plating layer is lead wiring 3 And the side terminals 10 for connecting the mounting terminals 11. With this structure, it is not necessary to set the height with respect to the substrate surface with the electrode column, the solder ball or the solder bump as shown in FIG. 35 for the mounting terminal 11, so that the SAW device can be obtained at low cost. Further, since solder balls and solder bumps are not used for the mounting terminals, connection by Cu plating becomes possible when used as a component with a built-in substrate as described in FIG.

  Further, according to the present embodiment, since the mounting terminals are formed on the resin portion constituting the ceiling layer having a large area, the positions of the mounting terminals can be arbitrarily selected. Therefore, the mounting terminals should be arranged at the places desired by the customer. Can.

  Further, according to the present embodiment, by forming the wiring (side wiring) connecting the comb electrode portion and the mounting terminal to the side wall portion of the SAW device, the sealing structure of the joint portion of the outer wall layer and the ceiling layer is assured. Thus, the airtightness of the hollow portion can be improved.

  As described above, according to the present embodiment, the SAW device extremely excellent in mold pressure resistance and reduced in height and size can be used for arranging the mounting terminals without increasing the thickness of parts. SAW devices with a degree of freedom can be manufactured at low cost.

  Next, a method of manufacturing the SAW device of Example 1 will be described with reference to FIGS. 13 to 21. FIG. As in the first embodiment, the comb electrode (IDT electrode) 2 and the comb electrode 2 are connected to the main surface of a lithium tantalate wafer (piezoelectric wafer) 1 which is a piezoelectric substrate and extended to the outer edge of the piezoelectric wafer. A pair of lead wires 3 to be provided is formed on each of the facing side surfaces of the outer wall layer 6. The comb-tooth electrode 2 and the lead-out wiring 3 contain any one of Al, Cu, Au, Cr, Ru, Ni, Mg, Ti, W, V, Ta, Mo, Ag, In, and Sn as a main component. These materials, or compounds of these materials with oxygen, nitrogen, silicon, or alloys of these materials, or intermetallic compounds, are formed by patterning of thin films formed by laminating these in multiple layers.

  Next, the outer wall layer 6 is formed around the outer periphery of the piezoelectric substrate 1 including the extended portion of the lead-out wiring 3 to form a hollow portion to be an operation space of the comb electrode 2. The outer wall layer 6 is formed by application of a photosensitive heat-resistant resin, which is preferably made of polyimide or epoxy resin, and a photolithographic process using an exposure mask. It is desirable to mix an inorganic filler suitable for white mica into the resin constituting the outer wall layer 6 to improve the elastic modulus and to increase the mechanical strength.

  A photosensitive and heat-resistant resin plate material is suitably fixed which covers the outer wall layer 6 and is preferably made of polyimide or epoxy resin mixed with the same inorganic filler as described above, and is used as a component of the ceiling plate 7. The resin plate material of the ceiling plate 7 seals a hollow portion which bridges the periphery to the outer wall layer 6 surrounding each of the comb-like electrodes 2 to secure an operation space of the comb-like electrodes 2. ... FIG.

  Next, the components of the ceiling plate 7 are separated into patterns for each individual SAW device. In the individual piece separation, the photosensitive mask material is used for the photosensitive heat-resistant resin plate material to be the ceiling plate 7, and the heat-resistant resin plate material in the individual piece separation part is removed in a photolithographic process of exposing to ultraviolet light and developing. ... FIG.

  In a state in which the individual ceiling plates 7 are separated in a piece-by-piece manner by processing using the photolithography process, the pair of opposing side surfaces of the outer wall layer 6 and the pair of opposing outer wall layers 6 of the ceiling plate 7 are separated. A step-like stepped surface is formed on the side surface connected to the side surface from the ceiling plate 7 to the outer wall layer 6. ... FIG.

  After the components of the ceiling plate 7 are separated into patterns of individual SAW devices, a drawing is performed between the stepped surface which is stepped from the ceiling plate 7 to the outer wall layer 6 and the adjacent SAW devices. A metal film is deposited to cover the line 3. This metal film becomes a seed layer 15 for formation of side wiring and mounting terminals using electrolytic plating in a later step. ... FIG.

  The type of the seed layer 15 is not particularly limited as long as it is a metal to which plating is attached, such as Cu or Au. In this example, Cu was formed to a thickness of 4000 Å on a 200 Å-thick film of Ti. When a resin such as polyimide is used as the ceiling layer, adhesion to metal is poor. Therefore, by performing plasma treatment or blasting on the resin surface as pretreatment, adhesion is improved by performing surface roughening treatment. can do. According to experiments, it has been confirmed that when a polyimide resin is roughened to a surface roughness Ra of 0.3 to 0.5 μm by blasting, a metal film having good adhesion can be obtained.

  Note that, in FIG. 15 and thereafter, only the portions of two adjacent SAW devices are enlarged and displayed, and the left and right portions of the figure are simplified and shown. A photosensitive resist is applied on the seed layer 15 shown in FIG. 16, and the seed layer 15 in the portion to be plated with the side wiring and the mounting terminal is exposed in a photolithography process using an exposure mask. A resist 16 is left in the portion where plating is unnecessary. ... FIG.

  Exposed in a plurality of sections (see FIG. 12) across the outer edge of the piezoelectric substrate 1 connected to the pair of opposite side surfaces of the outer wall layer 6 and the opposite surface of the outer wall layer 6 of the ceiling plate 7 using a resist pattern. On the seed layer 15, the metal plating layer 10 'is grown. As the metal to be plated, Ni, Au, Cu or the like is used. In this embodiment, Cu was formed to a thickness of about 10 μm by copper sulfate plating. If necessary, a solder bump may be formed on the portion to be the mounting terminal of the plated layer 10 ′ using a method such as printing. ... FIG. 18

  The process described in FIGS. 16 to 18 is a method of forming a plated layer 10 'to be the mounting terminals 11 and the side wiring 10 using electrolytic plating, but forming the plated layer 10' by electroless plating. It can also be done. In the case of employing the electroless plating, for example, at the time of film formation of the seed layer by sputtering, sputtering film formation may be selectively performed on a portion where the plating layer 10 'is formed using a metal mask.

  After the plating layer 10 'is formed, the resist 16 is peeled off with a peeling agent, or dissolved and removed with a solution such as acetone. The seed layer 15 is exposed in the portion where the resist is removed. ... FIG.

  The etching solution is used to etch away the seed layer 15 exposed on the surface of the top plate 7, the envelope layer 6, and the surface of the piezoelectric substrate 1 by etching. ... FIG. 20

  After each process described above, the piezoelectric substrate 1 is cut by dicing at the boundaries of the individual SAW devices to be separated into individual SAW devices. The separated individual SAW devices are as shown in FIG. 1 and FIG. ... Fig. 21

  Then, the upper surface of the ceiling plate 7 of the metal plating layer electrically connected to the lead wiring 3 at the outer edge of the piezoelectric substrate 1 by the metal plating layer 10 ′ is used as the mounting terminal 11. Since the lead-out wiring 3 and the mounting terminal 11 are connected by the side wiring 10 passing through the side surface of the outer wall layer 6, opening processing of the outer wall layer and opening processing of the ceiling plate are required as described in the prior art. Therefore, the SAW device can be manufactured at low cost.

  As described above, in the SAW device manufactured by the manufacturing method according to the present embodiment, since the mounting terminals are formed on the resin portion constituting the ceiling layer having a large area, the positions of the mounting terminals can be arbitrarily selected, and the customer desires The mounting terminals can be arranged in places. In addition, by forming a wire (side wire) connecting the comb electrode portion and the mounting terminal on the side wall portion of the SAW device, the sealing structure of the bonding portion between the outer wall layer and the ceiling layer becomes reliable, and the hollow portion is airtight. Improve.

  In each of the embodiments described above, on the upper surface of the side wiring 10 and the ceiling plate 7 which electrically connect the lead wire 3 drawn to the peripheral edge of the piezoelectric substrate 1 from the side surface of the ceiling plate 7 through the side surface of the outer wall layer 6 The plated layer for forming the mounting terminals (component terminals) 11 is referred to as "gradiently curved inclined surface" in the first embodiment, and is referred to as "step surface curved in a step-like manner" in the second embodiment. The present invention is not limited to this. “The side surface of the ceiling plate 7 may be flush with the side surface of the outer wall layer 6, and the side wiring 10 may be formed on the vertical side surface.

  The above-mentioned processing to make the same vertical vertical pattern the outer wall layer 6 from the ceiling plate 7 by the selection of the blade shape of the dicing blade described in the first embodiment or by the photolithography process described in the second embodiment. It can form by doing.

  By the way, for example, when mounting the SAW device according to the second embodiment of the present invention shown in FIG. 11 on a mounting substrate, solder balls are provided on the terminals (component terminals) of the device to solder weld on the terminal pads of the mounting substrate. Think about the case. In the SAW device shown in FIG. 11, the mounting terminals (component terminals) 11 can be arranged on the mounting terminals 11 formed of a metal layer on the ceiling plate 7 without using plated pillars or solder bumps. That is, on the ceiling plate 7, the plating pillars and the solder bumps are not formed at the fixed positions.

  FIG. 22 is an explanatory view of the state where the SAW device shown in FIG. 11 is mounted on the terminal pads of the mounting substrate by soldering. First, the solder ball 5 is attached to the mounting terminal 11 of the SAW device. The solder balls 5 can be disposed on the mounting terminals 11 using a solder ball distribution device.

  When mounting the SAW device to which the solder ball 5 is mounted on the mounting substrate 8, as shown in FIG. 22, the solder ball 5 is positioned on the terminal pad 9 formed on the mounting terminal 11 using a mounting machine Pass through. While passing through the reflow furnace, the solder balls 5 melt and weld the mounting terminals 11 to the terminal pads 9. However, at this time, a molten solder may cause the solder flow to wet the side wiring 10 and a phenomenon may occur in which the required amount of solder can not be secured between the mounting terminal 11 and the terminal pad 9. FIG. 23 is an explanatory view of a state in which the solder between the mounting terminal 11 and the terminal pad 9 gets wet to the side wiring due to the solder flow. As a result of the reduction in the amount of solder between the mounting terminal 11 and the terminal pad 9, there is a possibility that a conduction failure or an uneven interval between the two will occur. The present embodiment is configured to prevent the occurrence of such solder flow.

  FIG. 24 is a cross-sectional view taken along the line XX in FIG. 25 for explaining a SAW device to which the third embodiment of the piezoelectric device of the present invention provided with a solder flow prevention layer is applied. FIG. 25 is a plan view of a SAW device to which the third embodiment of the piezoelectric device of the present invention provided with a solder flow prevention layer is applied. In FIG. 24 and FIG. 25, the same functional parts as in the drawings of each of the embodiments are given the same reference numerals. Reference numeral 31 denotes a solder flow prevention layer, and 32 denotes a barrier metal.

  The solder flow prevention layer 31 is formed in a region extending to the outer periphery of the upper surface of the piezoelectric substrate 1 through the ceiling plate 7 and the side surface and the outer wall layer 6 except for the portion forming the barrier metal 32. In order to indicate that the solder flow prevention layer 31 is positioned on the ceiling plate, the peripheral position of the solder flow prevention layer 31 is illustrated as being retracted from the edge of the ceiling plate 7. It is illustrated similarly in the following similar drawings.

The SAW device according to the third embodiment includes the periphery of the mounting terminal 11 provided on the ceiling plate 7 and includes the side surface extending to the metal plating layer 10 ′ on the outer edge of the piezoelectric substrate 1 (the outer periphery of the upper surface of the piezoelectric substrate 1). A solder flow prevention layer 31 is provided on the entire surface. The solder flow prevention layer 31 is formed by applying a solution of thermosetting resin such as polyimide or liquid glass by spray coating or spin coating and baking it. Alternatively, it can be formed by sputtering silica (SiO ₂ ).

  The solder flow prevention layer 31 in the portion of the mounting terminal 11 shown in FIG. 24 is removed using a photolithographic method, and is opened as shown in FIG. If the mounting terminal 11 is plated with copper (Cu), nickel (Ni) plating is applied to the portion constituting the mounting terminal 11 exposed to the opening, and then gold (Au) plating is applied as an anti-oxidation film to form a barrier. Form a layer of metal 32. Gold (Au) plating is not essential. Solder balls are provided on the barrier metal 32 and are welded and mounted on the terminal pads of the mounting substrate. Alternatively, solder balls or solder bumps may be provided directly on the terminal window 33 without forming the barrier metal 32. Although the barrier metal 32 is not an essential component, it is desirable to provide it in consideration of mounting on the mounting substrate terminal using solder.

  FIG. 26 illustrates a state in which solder balls are provided on the mounting terminals (component terminals) of the SAW device to which the piezoelectric device according to the third embodiment of the present invention provided with the solder flow prevention layer is applied FIG. FIG. 27 is a plan view of a SAW device to which Example 3 of the piezoelectric device of the present invention provided with a solder flow prevention layer is applied.

  In FIG. 26 and FIG. 27, the solder balls 5 are provided on the byria metal 32 formed on the mounting terminals 11 provided on the ceiling plate 7. The solder balls 5 are arranged using a solder ball distribution device. As described above, when the SAW device provided with the solder balls 5 is mounted on the mounting substrate 8 as described in 22 above, the solder balls 5 of the terminal pads 9 of the mounting substrate 8 are placed and the terminals are passed through a reflow furnace. Solder weld on the pad 9.

  According to the present embodiment, the solder flow prevention layer 31 is provided, so that solder wraps around the side wiring portion when mounting facedown on the terminal pad 9 provided on the surface of the mounting substrate 8 using solder balls or the like. The reduction of the amount of solder interposed between the mounting terminal 11 (barrier metal 32) and the terminal pad 9 is avoided, and the defective soldering and the instability of the gap between the mounting substrate and the mounting substrate are prevented.

  FIG. 28 is a cross-sectional view taken along the line XX in FIG. 29 for explaining a SAW device to which Example 4 of the piezoelectric device of the present invention is applied. FIG. 29 is a plan view of a SAW device to which Example 4 of the piezoelectric device of the present invention is applied, and FIG. 28 corresponds to a cross section taken along the line XX of FIG. In the present embodiment, the solder flow prevention layer 31 is provided independently for each of the mounting terminals 11 (barrier metal 32). As shown in FIGS. 28 and 29, the solder flow prevention layer 31 of the present embodiment is formed separately around the side wiring 10 and the mounting terminal 11, and portions such as the ceiling plate 7 and the outer wall layer 6 etc. Not formed. The barrier metal 32 and other configurations are the same as in the third embodiment.

  Also according to the present embodiment, the solder flow prevention layer 31 is provided, which results from wraparound of the solder in the side wiring portion when mounting facedown to the terminal pad 9 provided on the surface of the mounting substrate 8 using solder balls or the like. Thus, the reduction of the amount of solder interposed between the mounting terminals 11 (barrier metal 32) and the terminal pads 9 is avoided, and the defective soldering and the instability of the gap between the mounting substrate and the mounting substrate are prevented.

  FIG. 30 is a process diagram for explaining the main parts of the method for manufacturing the SAW device described in the third embodiment of the present invention provided with a solder flow prevention layer. FIG. 30A shows a SAW device in a state where the steps described in FIGS. 13 to 20 have been performed. The plated terminals 10 'constituting the mounting terminals 11 from the ceiling plate 7 to the lead wiring and the side wiring 10 are made of copper (Cu) or nickel (Ni) or their alloys.

FIG. 30 (b) shows a state in which a polyimide solution is spray applied, which is fired and cured to form a solder flow prevention layer 31. In addition to spin coating, spin coating or printing may be used to apply the polyimide solution. Further, not limited to the polyimide solution, other thermosetting resin, or a coated film of glass, or a sputtered film of silica (SiO ₂ ) can also be used.

  FIG. 30C shows a state in which a window (terminal window 33) is formed in the mounting terminal formation portion. A photoresist is applied to the solder flow prevention layer 31 of polyimide, and the terminal window 33 is formed by a photolithographic process including exposure to ultraviolet light through an exposure mask provided with a predetermined opening and a development process.

  In FIG. 30D, nickel (Ni) is plated on the terminal window 33 provided in the mounting terminal formation portion, and then gold (Au) is plated to form a barrier metal 32. Solder balls are provided on the barrier metal 32 in the same manner as described with reference to FIG. 26, and welded and mounted on the terminal pads of the mounting substrate. Alternatively, solder balls or solder bumps may be provided directly on the terminal window 33 without forming a barrier metal.

  Also according to the present embodiment, as in the third embodiment, by providing the solder flow prevention layer 31, the side surface wiring portion in the case of face-down mounting on the terminal pad 9 provided on the surface of the mounting substrate 8 using solder balls etc. Reduction of the amount of solder interposed between the mounting terminal 11 (barrier metal 32) and the terminal pad 9 due to the wraparound of solder is prevented, and defective soldering and instability of the gap between the mounting substrate are prevented. Ru.

  31 is a cross-sectional view taken along the line X-X in FIG. 32 for explaining the main part of a SAW device to which the fifth embodiment of the piezoelectric device of the present invention is applied. FIG. 32 is a plan view for explaining the main part of a SAW device to which the fifth embodiment of the piezoelectric device of the present invention is applied. In the fifth embodiment, the ceiling plate constituting the device and the device are provided with a crushing prevention layer. Crushing occurs in the working space (the chamber accommodating the IDT portion, the hollow portion) in response to pressure application in the step of bonding the ceiling plate 7 described in FIG. 3 or FIG. 13 and the step of mounting on the mounting substrate. Can be further prevented. Furthermore, the improvement of mold resistance at the time of modularizing a piezoelectric device can also be expected.

  In the SAW device of this embodiment, a plurality of electrically separated side wirings 10 and mounting terminals (component terminals) 11 are formed across the side surface of the device and the upper surface of the ceiling plate 7 and the above-mentioned side wiring A crushing prevention layer 34 is provided in a portion other than the mounting terminals 10 and the mounting terminals (component terminals) 11. The anti-crush layer 34 is formed using metal or resin. In the case of metal, it is formed, for example, by plating with copper (Cu), nickel (Ni) or the like, or by vapor deposition or sputtering. The crushing prevention layer 34 can be formed simultaneously with the side wiring 10 and the mounting terminal (component terminal) 11.

  Further, a layer of thermosetting resin such as polyimide resin, polyester resin, epoxy resin can be used as the crushing prevention layer 34. These resin solutions are applied by spray or spin, and a collapse prevention layer 34 is formed in a region as shown in FIG.

  In the present embodiment, the solder flow prevention layer 31 is provided on the above-described crushing prevention layer 34, and thereafter, the solder flow prevention layer 31 similar to the third embodiment described in FIG. 24 is formed. FIG. 33 is a cross-sectional view taken along the line X-X in FIG. 34 for explaining a SAW device in which the solder flow prevention layer 31 is provided on the anti-crush layer 34. FIG. 34 is a plan view of a SAW device in which a solder flow prevention layer is provided on a crushing prevention layer. As shown in FIGS. 33 and 34, an opening for a mounting terminal is formed in the solder flow prevention layer 31, and a barrier metal 32 is provided in this opening as necessary. The solder flow prevention layer 31 may be the same as that of the fourth embodiment.

  According to the present embodiment, it is possible to further prevent crushing of the working space (the chamber accommodating the IDT portion, the hollow portion) due to the pressure application in the bonding process of the ceiling plate material and the mounting process on the mounting substrate. Then, the solder flow prevention layer 31 similar to that of the above embodiment is provided on the anti-crush layer, so that the side surface of the mounting pad 8 is mounted on the surface of the mounting substrate 8 by using a solder ball or the like. A reduction in the amount of solder interposed between the mounting terminal 11 (barrier metal 32) and the terminal pad 9 due to the wraparound of the solder into the wiring portion is avoided, and a defect with soldering or a destabilization of the gap between the mounting substrate Is prevented.

  The present invention is not limited to the SAW device in the above embodiment, and needless to say, can be applied to a quartz oscillator, a MEMS resonator, and other electronic devices having similar problems.

1 Piezoelectric substrate 2 Comb electrode (IDT electrode)
Reference Signs List 3 lead wiring 4 electrode pillar 5 mounting terminal 6 outer wall layer 7 ceiling plate 8 mounting board 9 terminal pad 10 side wiring 10 ′ plated layer 11 mounting terminal (component terminal)
12 dicing blade 13 photomask 14 ultraviolet ray 15 seed layer 16 resist 20 component embedded substrate 21 electronic component 22 component terminal 23 resin 24 opening 25 electrode column 26 cut line 31 solder flow prevention layer 32 barrier metal 32 terminal window 32 crushing prevention layer

Claims (10)

A piezoelectric substrate, a comb-tooth electrode formed on the main surface of the piezoelectric substrate, a lead-out wire connected to the comb-tooth electrode and extended to an outer edge of the piezoelectric substrate, and the piezoelectric substrate including the lead-out wire And an outer wall layer which is installed around the outer circumference to form a hollow portion which becomes an operation space of the comb electrode, and a ceiling plate which bridges the outer wall layer to seal the hollow portion. ,
The ceiling plate is made of a heat-resistant resin whose mechanical strength is improved by mixing an inorganic filler.
The lead-out wires are respectively formed on a pair of opposing side surfaces of the outer wall layer,
The piezoelectric substrate connected to an upper surface connected to a pair of opposite side surfaces of the outer wall layer and a pair of opposite side surfaces of the outer wall layer of the ceiling plate and a pair of opposite side surfaces of the outer wall layer of the piezoelectric substrate A metal plating layer insulated in a plurality of sections across the outer edge of the
The metal plating layer is electrically connected to the lead-out line at the outer edge of the piezoelectric substrate,
The upper surface of the ceiling plate of the metal plating layer is a mounting terminal, and the side surface of the outer wall layer of the metal plating layer is a side wiring connecting the lead wiring and the mounting terminal ,
The side surface connected to the pair of opposing side surfaces of the outer wall layer and the pair of opposite side surfaces of the outer wall layer of the ceiling plate has an inclined surface which gradually curves from the ceiling plate to the outer wall layer. A piezoelectric device characterized by A piezoelectric substrate, a comb-tooth electrode formed on the main surface of the piezoelectric substrate, a lead-out wire connected to the comb-tooth electrode and extended to an outer edge of the piezoelectric substrate, and the piezoelectric substrate including the lead-out wire And an outer wall layer which is installed around the outer circumference to form a hollow portion which becomes an operation space of the comb electrode, and a ceiling plate which bridges the outer wall layer to seal the hollow portion. ,
The ceiling plate is made of a heat-resistant resin whose mechanical strength is improved by mixing an inorganic filler.
The lead-out wires are respectively formed on a pair of opposing side surfaces of the outer wall layer,
The piezoelectric substrate connected to an upper surface connected to a pair of opposite side surfaces of the outer wall layer and a pair of opposite side surfaces of the outer wall layer of the ceiling plate and a pair of opposite side surfaces of the outer wall layer of the piezoelectric substrate A metal plating layer insulated in a plurality of sections across the outer edge of the
The metal plating layer is electrically connected to the lead-out line at the outer edge of the piezoelectric substrate,
The upper surface of the ceiling plate of the metal plating layer is a mounting terminal, and the side surface of the outer wall layer of the metal plating layer is a side wiring connecting the lead wiring and the mounting terminal ,
A piezoelectric device characterized in that a solder flow prevention layer is provided on the side surface extending to the metal plating layer provided on the outer edge of the piezoelectric substrate including the periphery of the mounting terminal provided on the ceiling plate . In claim 2 ,
A piezoelectric device, wherein the solder flow prevention layer is provided on the entire surface of the ceiling plate and the side surface except a barrier metal or a terminal window which is a part of the mounting terminal. In claim 2 ,
A piezoelectric device, wherein the solder flow prevention layer is provided independently for each of the mounting terminals. In claim 2 ,
The piezoelectric device is characterized in that allowed have a barrier metal layer over the mounting terminal. A comb-tooth electrode is formed on the main surface of a piezoelectric wafer constituting the piezoelectric substrate, and a lead-out wire connected to the comb-tooth electrode and extended to the outer edge of the piezoelectric substrate is formed on the pair of opposing side surfaces of the piezoelectric substrate. An electrode forming step;
An operation space forming step of setting an outer wall layer for forming a hollow portion to be an operation space of the comb electrode, around the outer periphery of the piezoelectric substrate including the lead-out wiring;
A ceiling plate setting step of sealing the hollow portion by bridging the periphery of a ceiling plate made of a heat-resistant resin plate mixed with an inorganic filler to the outer wall layer;
A ceiling plate patterning step of separating the ceiling plate into patterns of individual SAW devices;
The piezoelectric substrate connected to an upper surface connected to a pair of opposite side surfaces of the outer wall layer and a pair of opposite side surfaces of the outer wall layer of the ceiling plate and a pair of opposite side surfaces of the outer wall layer of the piezoelectric substrate Forming a metal plating layer in a plurality of sections across the outer edge of
A singulation step of dividing the bonded piezoelectric wafer and the ceiling plate into individual SAW devices after each of the above steps;
Including
The metal plating layer is electrically connected to the lead-out wiring at the outer edge of the piezoelectric substrate, the upper surface of the ceiling plate of the metal plating layer is used as a mounting terminal, and the side surface of the outer wall layer of the metal plating layer is Side wiring connecting the lead-out wiring and the mounting terminal ,
A method of manufacturing a piezoelectric device, wherein a cutting method using a dicing blade with a tapered angle is used as the ceiling plate patterning step . A comb-tooth electrode is formed on the main surface of a piezoelectric wafer constituting the piezoelectric substrate, and a lead-out wire connected to the comb-tooth electrode and extended to the outer edge of the piezoelectric substrate is formed on the pair of opposing side surfaces of the piezoelectric substrate. An electrode forming step;
An operation space forming step of setting an outer wall layer for forming a hollow portion to be an operation space of the comb electrode, around the outer periphery of the piezoelectric substrate including the lead-out wiring;
A ceiling plate setting step of sealing the hollow portion by bridging the periphery of a ceiling plate made of a heat-resistant resin plate mixed with an inorganic filler to the outer wall layer;
A ceiling plate patterning step of separating the ceiling plate into patterns of individual SAW devices;
The piezoelectric substrate connected to an upper surface connected to a pair of opposite side surfaces of the outer wall layer and a pair of opposite side surfaces of the outer wall layer of the ceiling plate and a pair of opposite side surfaces of the outer wall layer of the piezoelectric substrate Forming a metal plating layer in a plurality of sections across the outer edge of
A singulation step of dividing the bonded piezoelectric wafer and the ceiling plate into individual SAW devices after each of the above steps;
Including
The metal plating layer is electrically connected to the lead-out wiring at the outer edge of the piezoelectric substrate, the upper surface of the ceiling plate of the metal plating layer is used as a mounting terminal, and the side surface of the outer wall layer of the metal plating layer is Side wiring connecting the lead-out wiring and the mounting terminal ,
After the metal plating layer forming step of forming the metal plating layer, on the upper surface of the ceiling plate avoiding the barrier metal or terminal window which is a part of the mounting terminal and the metal plating layer on the outer edge of the piezoelectric substrate A method of manufacturing a piezoelectric device, comprising a solder flow prevention layer forming step of forming a solder flow prevention layer on the side surface . In claim 7 ,
A method of manufacturing a piezoelectric device, wherein the solder flow preventing layer is provided on the entire surface of the ceiling plate and the side surface excluding a barrier metal or a terminal window which is a part of the mounting terminal. In claim 7 ,
A method of manufacturing a piezoelectric device, wherein the solder flow prevention layer is provided independently for each of the mounting terminals. In claim 7 ,
A method of manufacturing a piezoelectric device, comprising a barrier metal layer forming step of forming a barrier metal layer on the mounting terminal.