JP6502666B2 - Piezoelectric device and method of manufacturing the same - Google Patents

Description

  The present invention relates to a piezoelectric device used, for example, in an electronic device and a method of manufacturing the same.

  The piezoelectric device generates thickness-shear vibration such that both sides of the piezoelectric base plate are displaced from each other by using the piezoelectric effect of the piezoelectric element, and generates a specific frequency. There has been proposed a piezoelectric device provided with a piezoelectric element mounted on an electrode pad provided on a substrate via a conductive adhesive (see, for example, Patent Document 1 below). The piezoelectric element has excitation electrodes on both main surfaces of the piezoelectric base plate, one end of the piezoelectric element being a fixed end connected to the upper surface of the substrate, and the other end being a free end spaced apart from the upper surface of the substrate Become a cantilevered support structure.

  In the method of manufacturing a piezoelectric device, a conductive adhesive is applied on an electrode pad provided on the upper surface of a package, a step of mounting a piezoelectric element on the conductive adhesive, and heat curing of the conductive adhesive. There is known a manufacturing method including a step of conductively fixing an electrode pad and a piezoelectric element, and a step of bonding a lid and a package (see, for example, Patent Document 2).

Japanese Patent Application Laid-Open No. 2002-111435 Unexamined-Japanese-Patent No. 2007-235340

  The piezoelectric device described above has a lower surface of the lead-out electrode when bonding between the lead-out electrode provided adjacent along one side of the piezoelectric element and the electrode pad provided on the upper surface of the substrate with a conductive adhesive. However, part of the conductive adhesive provided on the upper surface of the electrode pad protrudes from the electrode pad and adheres to the excitation electrode, which may change the resonant frequency of the piezoelectric element.

  Further, in the method of manufacturing the piezoelectric device described above, when the piezoelectric element is placed on the conductive adhesive, the position of the conductive adhesive is hidden by the lead-out electrode of the piezoelectric element, and thus the coated diameter of the conductive adhesive Of the piezoelectric element may come into contact with the upper surface of the substrate.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a piezoelectric device capable of reducing fluctuation of the oscillation frequency of a piezoelectric element and a method of manufacturing the same.

A piezoelectric device according to one aspect of the present invention comprises a substrate, an electrode pad provided on the upper surface of the substrate, a conductive adhesive provided on the electrode pad, a rectangular piezoelectric element plate, and a piezoelectric element plate. The piezoelectric element plate is exposed on the upper surfaces of a pair of lead-out electrodes provided along the one side of the piezoelectric base plate with an excitation electrode provided on the upper and lower surfaces and a gap between the excitation electrodes. Mounted on the electrode pad through the conductive adhesive, and the first concave portion provided in the second and the second concave portion provided so that the piezoelectric base plate is exposed on the lower surface of the pair of lead electrodes A piezoelectric element and a lid provided for airtightly sealing the piezoelectric element, the first concave portion and the second concave portion being provided at a position overlapping in plan view, outside the conductive adhesive periphery, in plan view, is provided in the second recess, the opening area of the second recess, the It is larger than an opening area of the recess.

In the method of manufacturing a piezoelectric device according to one aspect of the present invention, a rectangular piezoelectric base plate, excitation electrodes provided on upper and lower surfaces of the piezoelectric base plate, and one side of the piezoelectric base plate with the excitation electrodes spaced apart So as to expose the piezoelectric element plate on the lower surface of the pair of lead-out electrodes, the first recess provided so that the piezoelectric element plate is exposed on the upper surface of the pair of lead-out electrodes, A piezoelectric element forming step of forming a piezoelectric element having a second concave portion provided and the opening area of the second concave portion being larger than the opening area of the first concave portion ; and an electrode pad provided on the package The piezoelectric element is placed on the conductive adhesive so that the conductive adhesive applying step of applying the conductive adhesive to the surface and the outer peripheral edge of the conductive adhesive are positioned in the second recess in plan view. Heat curing the conductive adhesive, and A piezoelectric element adhering step of conducting fixing the electrode pad and the piezoelectric element, so as to hermetically seal the piezoelectric element includes a lid bonding process for bonding the lid to the package.

A piezoelectric device according to one aspect of the present invention comprises a substrate, an electrode pad provided on the upper surface of the substrate, a conductive adhesive provided on the electrode pad, a rectangular piezoelectric element plate, and a piezoelectric element plate. The piezoelectric element plate is exposed on the upper surfaces of a pair of lead-out electrodes provided along the one side of the piezoelectric base plate with an excitation electrode provided on the upper and lower surfaces and a gap between the excitation electrodes. Mounted on the electrode pad through the conductive adhesive, and the first concave portion provided in the second and the second concave portion provided so that the piezoelectric base plate is exposed on the lower surface of the pair of lead electrodes A piezoelectric element and a lid provided for airtightly sealing the piezoelectric element, the first concave portion and the second concave portion being provided at a position overlapping in plan view, outside the conductive adhesive periphery, in plan view, is provided in the second recess, the opening area of the second recess, the It is larger than an opening area of the recess. By doing this, the conductive adhesive is adhered onto the electrode pad in such a manner that the conductive adhesive penetrates into the second recess provided on the lower surface of the lead-out electrode. Can be suppressed, and adhesion of the conductive adhesive to the excitation electrode can be reduced. Therefore, such a piezoelectric device can suppress the fluctuation of the oscillation frequency of the piezoelectric element caused by the adhesion of the conductive adhesive to the excitation electrode.

In the method of manufacturing a piezoelectric device according to one aspect of the present invention, a rectangular piezoelectric base plate, excitation electrodes provided on upper and lower surfaces of the piezoelectric base plate, and one side of the piezoelectric base plate with the excitation electrodes spaced apart So as to expose the piezoelectric element plate on the lower surface of the pair of lead-out electrodes, the first recess provided so that the piezoelectric element plate is exposed on the upper surface of the pair of lead-out electrodes, A piezoelectric element forming step of forming a piezoelectric element having a second concave portion provided and the opening area of the second concave portion being larger than the opening area of the first concave portion ; and an electrode pad provided on the package The piezoelectric element is placed on the conductive adhesive so that the conductive adhesive applying step of applying the conductive adhesive to the surface and the outer peripheral edge of the conductive adhesive are positioned in the second recess in plan view. Heat curing the conductive adhesive, and A piezoelectric element adhering step of conducting fixing the electrode pad and the piezoelectric element, so as to hermetically seal the piezoelectric element includes a lid bonding process for bonding the lid to the package. By doing this, it is possible to determine whether the piezoelectric element is pressed too much against the conductive adhesive, so that the free end of the piezoelectric element is in contact with the upper surface of the substrate or the conductive adhesive serves as the excitation electrode. Productivity can be improved because the adhered one can be sorted before measuring the characteristics of the piezoelectric device.

It is an exploded perspective view showing a piezoelectric device in this embodiment. (A) It is sectional drawing in AA of the piezoelectric device shown by FIG. 1, (b) It is the elements on larger scale of X1 location of Fig.2 (a). It is a top view which shows the state which removed the cover body of the piezoelectric device in this embodiment. It is a see-through | perspective top view which shows the piezoelectric element which comprises the piezoelectric device in this embodiment. It is a perspective view which shows the piezoelectric element mounting apparatus used with the manufacturing method of the piezoelectric device of this embodiment. (A) It is sectional drawing which shows the state which has recognized the electrode pad in the 1st camera part in the electroconductive adhesive application process which is a manufacturing method of the piezoelectric device of this embodiment, (b) The piezoelectric device of this embodiment FIG. 6C is a cross-sectional view showing a state in which the conductive adhesive is applied by the first nozzle in the conductive adhesive applying step which is the method of manufacturing the piezoelectric device, and (c) It is sectional drawing which shows the state which has recognized the electroconductive adhesive in a 2nd camera part in a mounting process. (A) It is sectional drawing which shows the state which has mounted the piezoelectric element on the said conductive adhesive by the 2nd nozzle in the piezoelectric element mounting process which is a manufacturing method of the piezoelectric device of this embodiment, b) It is sectional drawing which shows the piezoelectric element adhering process which is a manufacturing method of the piezoelectric device of this embodiment, (c) It is sectional drawing which shows the cover joining process which is a manufacturing method of the piezoelectric device of this embodiment.

(Piezoelectric device)
The piezoelectric device in the present embodiment includes a package 110 and a piezoelectric element 120 joined to the package 110 as shown in FIGS. 1 and 2. In the package 110, a housing space K surrounded by the upper surface of the substrate 110a and the inner surface of the frame 110b is formed. Such a piezoelectric device is used to output a reference signal used in an electronic device or the like.

  The substrate 110 a has a rectangular shape and functions as a mounting member for mounting the piezoelectric element 120 mounted on the upper surface. A pair of electrode pads 111 for mounting the piezoelectric element 120 is provided on the top surface of the substrate 110 a.

  In addition, external terminals 112 are provided at the four corners of the lower surface of the substrate 110a. Also, two of the four external terminals 112 are electrically connected to the piezoelectric element 120. Further, a pair of external terminals 112 electrically connected to the piezoelectric element 120 are provided to be located diagonally on the lower surface of the substrate 110a.

  The substrate 110a is made of an insulating layer which is a ceramic material such as alumina ceramics or glass-ceramics. The substrate 110a may be formed by using a single insulating layer or by stacking a plurality of insulating layers. A wiring pattern (not shown) for electrically connecting the electrode pad 111 provided on the upper surface of the frame 110b and the external terminal 112 provided on the lower surface of the substrate 110a on the surface and inside of the substrate 110a. And via conductors (not shown).

  The frame 110 b is disposed on the upper surface of the substrate 110 a and is for forming the accommodation space K on the upper surface of the substrate 110 a. The frame 110 b is made of, for example, a ceramic material such as alumina ceramic or glass-ceramics, and is integrally formed with the substrate 110 a.

  The electrode pad 111 is for mounting the piezoelectric element 120. The electrode pads 111 are provided in a pair on the upper surface of the substrate 110a, and are provided adjacent along one side of the inner peripheral edge of the substrate 110a inside the frame 110b.

  The external terminals 112 are used to bond to mounting pads (not shown) on an external mounting substrate of an electric device or the like. The external terminals 112 are provided at the four corners of the lower surface of the substrate 110a. At least one of the external terminals 112 is electrically connected to the sealing conductor pattern 113 via a via conductor (not shown). In addition, at least one of the external terminals 112 is connected to a mounting pad connected to a ground potential which is a reference potential on a mounting substrate of an electronic device or the like. Thereby, the lid 130 joined to the sealing conductor pattern 113 is connected to the external terminal 112 which is at the ground potential. Therefore, the shielding property in the accommodation space K by the lid 130 is improved.

  The sealing conductor pattern 113 plays a role of improving the wettability of the bonding member 131 when bonding with the lid 130 via the bonding member 131. The sealing conductor pattern 113 is electrically connected to at least one of the external terminals 112 via a via conductor (not shown). The sealing conductor pattern 113 is formed to have a thickness of, for example, 10 to 25 μm by applying nickel plating and gold plating sequentially on the surface of a conductor pattern made of, for example, tungsten or molybdenum in the form of annularly surrounding the upper surface of the frame 110b. It is done.

  Here, a method for manufacturing the substrate 110a and the frame 110b will be described. When the substrate 110a and the frame 110b are made of alumina ceramic, first, a plurality of ceramic green sheets obtained by adding and mixing an appropriate organic solvent or the like to a predetermined ceramic material powder are prepared. Further, a predetermined conductive paste is applied by screen printing or the like known in the prior art in the surface of the ceramic green sheet or in the through holes which are punched in advance by punching or the like. Furthermore, these green sheets are stacked and press-formed, and fired at a high temperature. Finally, nickel plating, gold plating, silver palladium, or the like is performed on a predetermined portion of the conductor pattern, specifically, a portion to be the electrode pad 111, the external terminal 112, and the sealing conductor pattern 113. The conductor paste is made of, for example, a sintered body of metal powder such as tungsten, molybdenum, copper, silver or silver palladium.

  The piezoelectric element 120 is bonded onto the electrode pad 111 via a conductive adhesive 140, as shown in FIGS. 1 and 2. The piezoelectric element 120 plays a role of oscillating a reference signal of an electronic device or the like by stable mechanical vibration and piezoelectric effect.

  Further, as shown in FIGS. 1 and 2, the piezoelectric element 120 has a structure in which the excitation electrode 122 and the lead-out electrode 123 are attached to the upper surface and the lower surface of the piezoelectric base plate 121 made of quartz. doing. The excitation electrode 122 is formed by depositing and forming a metal on each of the upper surface and the lower surface of the piezoelectric element plate 121 in a predetermined pattern. The excitation electrode 122 includes a first excitation electrode 122 a on the upper surface and a second excitation electrode 122 b on the lower surface.

  The lead-out electrodes 123 extend from the excitation electrode 122 toward one side of the piezoelectric base plate 121. The extraction electrode 123 includes a first extraction electrode 123a on the upper surface and a second extraction electrode 123b on the lower surface. The first lead-out electrode 123 a is drawn out from the first excitation electrode 122 a and provided so as to extend toward one side of the piezoelectric base plate 121. The second lead-out electrode 123 b is drawn out from the second excitation electrode 122 b and provided so as to extend toward one side of the piezoelectric base plate 121. That is, the lead-out electrode 123 is provided in a shape along the long side or the short side of the piezoelectric base plate 121. Further, in the present embodiment, one end of the piezoelectric element 120 connected to the first electrode pad 111a and the second electrode pad 111b is a fixed end connected to the upper surface of the substrate 110a, and the other end is between the upper surface of the substrate 110a The piezoelectric element 120 is fixed on the substrate 110 a by a cantilevered support structure with free ends.

  Further, the first concave portion 124 is provided so that the piezoelectric element plate 121 is exposed to the upper surfaces of the first lead electrode 123a and the second lead electrode 123b. The second concave portion 125 is provided so that the piezoelectric base plate 121 is exposed to the lower surface of the first lead electrode 123a and the second lead electrode 123b. The quartz crystal element 120 is mounted on the electrode pad 111 such that the second concave portion 125 accommodates a part of the conductive adhesive 140 provided on the electrode pad 111. As described above, since the conductive adhesive 140 is bonded onto the electrode pad 111 so that the conductive adhesive 140 enters the second recess 125 provided on the lower surface of the pair of lead electrodes 123, the inside of the second recess 125 is obtained. The protrusion of the conductive adhesive 140 can be suppressed, and the adhesion of the conductive adhesive 140 to the excitation electrode 122 can be reduced. Therefore, such a piezoelectric device can suppress the fluctuation of the oscillation frequency of the piezoelectric element 120 caused by the adhesion of the conductive adhesive 140 to the excitation electrode 122.

  Further, by providing the first recess 124 on the upper surface of the lead electrode 123, even if the conductive adhesive 140 goes around to the upper surface of the lead electrode 123, it is easy to stay in the first recess 124. It is possible to reduce the adhesion of the conductive adhesive 140 to the first excitation electrode 122 a provided on the upper surface of the piezoelectric base plate 121.

  The groove portion 126 is for connecting the first concave portion 124 and the second concave portion 125 at the side surface of the piezoelectric base plate 121. It is provided so as to be connected via the groove portion 126 on the fixed end side of the first concave portion 124 and the second concave portion 125. The conductive adhesive 140 also intrudes into the groove 126 to increase the contact area between the conductive adhesive 140 and the lead-out electrode 123 of the quartz crystal element 120, and the conductive adhesive 140 and the quartz crystal element 120 are pulled out. The connection strength with the electrode 123 can be improved. In addition, a fillet in which the thickness in the vertical direction gradually increases from the electrode pad 111 to the groove 126 between the electrode pad 111 and the groove 126 by the conductive adhesive 140 also penetrating into the groove 126. Is formed. The curing of the conductive adhesive 140 makes it possible to secure the cantilever support structure more reliably by the residual stress acting to lift the free end side of the quartz crystal element 120.

  The opening area of the second recess 125 is set to be larger than the opening area of the first recess 124, as shown in FIG. By doing so, the conductive adhesive 140 remains in the second recess 125, and it is possible to prevent the conductive adhesive 140 from being further scooped on the upper surface of the lead electrode 125. It is possible to further suppress adhesion to the electrode 122a.

  Here, the operation of the piezoelectric element 120 will be described. In the piezoelectric element 120, when an alternating voltage from the outside is applied to the piezoelectric base plate 121 from the extraction electrode 123 via the excitation electrode 122, the piezoelectric base plate 121 causes excitation in a predetermined vibration mode and frequency. ing.

  The lid 130 is made of, for example, an Fe-Ni alloy (42 alloy) or an Fe-Ni-Co alloy (Kovar). Such a lid 130 hermetically seals the storage space K in a nitrogen gas atmosphere, a vacuum atmosphere, or the like. Specifically, the lid 130 is placed on the frame 110 b of the package 110 in a nitrogen atmosphere or a vacuum atmosphere, and the surface and lid of the sealing conductor pattern 113 provided on the top surface of the frame 110 b It joins to the frame 110b by applying a predetermined electric current and performing seam welding so that the joining member 131 of the body 130 may be melted.

  The conductive adhesive 140 contains a conductive powder as a conductive filler in a binder such as silicone resin, and as the conductive powder, aluminum, molybdenum, tungsten, platinum, palladium, silver, titanium, Those containing either nickel or nickel-iron or combinations thereof are used. Moreover, as a binder, a silicone resin, an epoxy resin, a polyimide resin, or bis maleimide resin is used, for example.

  The outer peripheral edge of the conductive adhesive 140 is provided so as to be located in the second recess 125 in plan view. When the conductive adhesive 140 is applied on the electrode pad 111 by using the adhesive having a viscosity of 35 to 45 Pa · s, the conductive adhesive 140 exceeds the bump electrode pad 111 and the substrate 110 a. It does not flow upward, stays on the electrode pad 111, and the thickness of the conductive adhesive 140 in the vertical direction is maintained. In addition, the conductive adhesive 140 can stay in the second recess 122 without flowing over the second recess 124 toward the second excitation electrode 122 b.

  The lid 130 has a rectangular shape, and is for airtightly sealing the accommodation space K in a vacuum state or the accommodation space K filled with nitrogen gas or the like. Specifically, the lid 130 is placed on the top surface of the sealing conductor pattern 113 provided on the frame 110 b in a predetermined atmosphere. Heat is applied to the bonding member 131 provided on the lower surface of the lid 130, whereby the sealing conductor pattern 113 is melted and bonded. Also, the lid 130 is made of, for example, an alloy containing at least one of iron, nickel or cobalt.

  The bonding member 131 is provided from the upper surface of the sealing conductor pattern 113 of the frame 110 b to the lower surface of the lid 130. The bonding member 131 is, for example, a glass that melts at 300 ° C. to 400 ° C. in the case of glass, and is made of, for example, low-melting glass or lead oxide glass containing vanadium. The glass is in the form of a paste in which a binder and a solvent are added, and after being melted and solidified, it bonds to other members. The bonding member 131 is provided, for example, by applying and drying a glass frit paste by a screen printing method. Further, when printing on the upper surface of the frame 110b, the bonding members 131 are printed so that the bonding members 131 overlap the four corners of the frame 110b. Therefore, the thickness of the bonding member 131 at the four corners is set to be thicker than the thickness of the other portion where the bonding member 131 is provided. The composition of this lead oxide glass is composed of lead oxide, lead fluoride, titanium dioxide, niobium oxide, bismuth oxide, boron oxide, zinc oxide, ferric oxide, copper oxide and calcium oxide.

  For example, in the case of the insulating resin, the bonding member 131 is made of an epoxy resin or a polyimide resin. The thickness of the bonding member 131 provided between the frame 110 b and the lid 130 is 30 to 100 μm.

  The bonding member 131 is, for example, in the case of gold-tin, the thickness of the layer of the bonding member 131 is 10 to 40 μm, for example, 70 to 80% of gold and 20 to 30% of tin. You may use In the case of silver solder, for example, the thickness of the layer of the bonding member 131 is 10 to 40 μm. For example, the component ratio is 70 to 80% of silver and 20 to 30% of copper. You may use the one of

  The piezoelectric device in this embodiment includes a substrate 110, an electrode pad 111 provided on the upper surface of the substrate 110, a conductive adhesive 140 provided on the electrode pad 111, a rectangular piezoelectric element plate 121, and piezoelectricity. The excitation electrodes 122 provided on the upper and lower surfaces of the base plate 121, a pair of lead electrodes 123 provided along one side of the piezoelectric base plate 121 with a gap between the excitation electrodes 122, and a pair of lead electrodes 123 A first recess 124 provided on the upper surface so that the piezoelectric base plate 121 is exposed, and a second recess 125 provided such that the piezoelectric base plate 121 is exposed on the lower surface of the pair of lead electrodes 123; A piezoelectric element 120 mounted on the electrode pad 111 via the conductive adhesive 140; and a lid 130 provided for hermetically sealing the piezoelectric element 120; Second indentation 125 and is provided to overlap in plan view, the outer peripheral edge of the conductive adhesive 140, in plan view, is provided in the second recess 125. By doing this, the conductive adhesive 140 is inserted into the second recess 125 provided on the lower surface of the lead-out electrode 123, and the piezoelectric element 120 is adhered on the electrode pad 111. The conductive adhesive 140 can be prevented from coming out of the two concave portions 125, and adhesion of the conductive adhesive 140 to the excitation electrode 122 can be reduced. Such a piezoelectric device can suppress the fluctuation of the oscillation frequency of the piezoelectric element 120 caused by the adhesion of the conductive adhesive 140 to the excitation electrode 122.

  Further, in the piezoelectric device according to the present embodiment, the first concave portion 124 is provided on the upper surface of the lead-out electrode 123 so that the conductive concave portion 140 is wound around the upper surface of the lead-out electrode 123. Since it is easy to stay inside, adhesion of the conductive adhesive 140 to the first excitation electrode 122 a provided on the upper surface of the piezoelectric base plate 121 can be reduced.

  Further, in the piezoelectric device in the present embodiment, the first recess 124 and the second recess 125 are connected at the side surface of the piezoelectric element plate 121. By doing this, the conductive adhesive 140 also intrudes into the side portion of the connected piezoelectric base plate 121, thereby increasing the contact area between the conductive adhesive 140 and the lead-out electrode 123 of the crystal element 120. Thus, the connection strength between the conductive adhesive 140 and the extraction electrode 123 of the crystal element 120 can be improved. In addition, a fillet in which the thickness in the vertical direction gradually increases from the electrode pad 111 to the groove 126 between the electrode pad 111 and the groove 126 by the conductive adhesive 140 also penetrating into the groove 126. Is formed. The curing of the conductive adhesive 140 makes it possible to secure the cantilever support structure more reliably by the residual stress acting to lift the free end side of the quartz crystal element 120.

  Further, the piezoelectric device in the present embodiment is provided such that the opening area of the second recess 125 is larger than the opening area of the first recess 124. By doing so, the conductive adhesive 140 remains in the second recess 125, and it is possible to suppress further creeping up on the upper surface of the lead electrode 125. It is possible to further suppress adhesion to 122.

(Piezoelectric element mounting device)
The piezoelectric element mounting apparatus, as shown in FIG. 5, includes a first nozzle NZ1 for applying the conductive adhesive 140 and a first camera unit CA1 for recognizing the position of the electrode pad 111. And a second nozzle NZ2 for adsorbing the piezoelectric element 120 and placing it on the conductive adhesive 140, and a second camera portion CA2 for recognizing the position of the electrode pad 111 or the conductive adhesive 140. The positional deviation width of the electrode pad relative to the package 110 is determined by the mounting means JS and the image data obtained from the first camera unit CA1, and the application position of the conductive adhesive 140 is corrected with respect to this positional deviation. The positional deviation width of the conductive adhesive 140 with respect to the electrode pad 111 is determined from the image data obtained from the camera unit CA2, and the mounting of the piezoelectric element 120 is performed for the positional deviation. Comprises a control unit SS for controlling the implementation means JS for correcting the location, the.

  Further, as shown in FIG. 5, the piezoelectric element mounting apparatus is provided with a first guide rail R1, and the first guide rail R1 is provided with a coating unit TS and a mounting unit JS. Further, the second guide rail is connected to the first guide rail R1 via the support PL. In this piezoelectric element mounting apparatus, the direction parallel to the second guide rail R2 is Y direction, the direction parallel to the first guide rail R1 is X direction, and the direction orthogonal to both the X direction and Y direction is Z direction I assume. Further, the direction of the angle formed by the intersection of the axis in the X direction and the axis in the Y direction is taken as the θ direction.

  The coating means TS is provided on the first guide rail R1. The coating unit TS includes a first nozzle NZ1, a first camera unit CA1, a first placement unit HB1, and a first movable unit. Further, the first movable portion is configured of an X-direction movable portion KB11, a Y-direction movable portion KB12, and a Z-direction movable portion KB13. Also, the coating unit TS is configured to recognize the positions of the first nozzle NZ1 and the electrode pad 111 for applying the conductive adhesive 140 to the electrode pad 111 of the package 110 arranged in the package arrangement jig PJ. And one camera unit CA1. The first nozzle NZ1 and the first camera unit CA1 are arranged in parallel to the first placement unit HB1 of the coating means TS.

  These coating means TS are movable back and forth in the Z direction, and move in the Z direction when the conductive adhesive 140 is applied to the package 110 of the package arrangement jig PJ. Also, when moving to the package 110, it moves in the X direction.

  The first camera unit CA1 plays a role in capturing image data indicating the state of the electrode pad 111 of the package 110. Image data captured by the first camera unit CA1 is stored in the storage unit ME. The storage unit ME plays a role of storing image data indicating the position of the electrode pad 111 of the package 110 obtained from the first camera unit CA1.

  The mounting means JS is provided in the first guide rail R1. The mounting means JS includes a second nozzle NZ2, a second camera unit CA2, a second arrangement unit HB2, and a second movable unit. The second nozzle NZ2 and the second camera unit CA2 are disposed at the tip of the second arrangement unit HB2. The second movable portion is configured by an X-direction movable portion KB21, a Y-direction movable portion KB22, and a Z-direction movable portion KB23. Further, the mounting means JS adsorbs the piezoelectric elements 120 arranged in the element arranging jig XJ, and the conduction of the electrode pads 111 provided in the accommodation space K of the package 110 arranged in the package arranging jig PJ. And the second camera part CA2 for recognizing the positions of the electrode pad 111 and the conductive adhesive 140. As shown in FIG. Further, the second nozzle NZ2 is connected to a vacuum pump (not shown), and air is sucked from suction holes (not shown) provided in the second nozzle NZ2 by operating the vacuum pump. . Thus, the piezoelectric elements 120 arranged in the element arrangement jig XJ are attracted to the second nozzle NZ2.

  These mounting means JS are movable back and forth in the Z direction, and move in the Z direction when the piezoelectric element 120 is adsorbed from the element arrangement jig XJ and mounted on the package 110. Also, when moving to the package 110 and when the piezoelectric element 120 is newly attracted, it moves in the X direction.

  The second nozzle NZ2 is disposed at the tip of the second arrangement portion HB2 so as to face the piezoelectric elements 120 arranged in the element arrangement jig XJ. In addition, the second nozzle NZ2 includes an X-direction movable portion KB21, a Y-direction movable portion KB22, a Z-direction movable portion KB23, and a pivoting portion (not shown). It is possible to operate in the direction.

  The second camera unit CA1 plays a role in capturing image data indicating the state of the electrode pad 111 of the package 110 and the conductive adhesive 140 applied on the electrode pad 111. Image data captured by the second camera unit CA2 is stored in the storage unit ME. The storage unit ME serves to store image data indicating the position of the electrode pad 111 and the position of the conductive adhesive 140 obtained from the second camera unit CA2.

  The control means SS is constituted by a computer, and is connected to the coating means TS, the suction means JS, and the storage unit ME. The control means SS controls the entire piezoelectric element mounting apparatus. That is, the control unit SS obtains numerical data of the distance between the provided electrode pad 111 and the frame 110b from the image data obtained from the first camera unit CA1, and based on the numerical data, the control unit SS It controls to correct the position of the first nozzle NZ1. Further, the control means SS obtains numerical data of the distance between the conductive adhesive provided and the frame 110b from the image data obtained from the second camera part CA2, and based on the numerical data, the mounting means JS Plays a role of controlling to correct the position of the second nozzle NZ2.

(Method of manufacturing piezoelectric device)
Hereinafter, a method of manufacturing the above-described piezoelectric device will be described. In the method of manufacturing the piezoelectric device, as shown in FIGS. 6 and 7, the rectangular piezoelectric element plate 121, the excitation electrode 122 provided on the upper and lower surfaces of the piezoelectric element plate 121, and the excitation electrode 122 are provided. A pair of lead-out electrodes 123 provided along one side of the piezoelectric base plate 121, and a first recess 124 provided so that the piezoelectric base plate is exposed on the upper surface of the pair of lead-out electrodes 123, and a pair of lead-out electrodes A piezoelectric element forming step of forming a piezoelectric element 120 having a second concave portion 125 provided on the lower surface of the piezoelectric element plate 121 so as to expose the piezoelectric element plate 121; and conducting the conductive adhesive 140 on the electrode pad 111 And the piezoelectric element 120 is placed on the conductive adhesive 140 so that the outer peripheral edge of the conductive adhesive 140 is positioned in the second recess 125 in plan view. Placement process, In order to bond the lid 130 and the substrate 110 a so as to hermetically seal the piezoelectric element 120 and the piezoelectric element fixing step of heating and curing the conductive adhesive 140 to electrically fix the electrode pad 111 and the piezoelectric element 120. And a lid bonding step.

(Piezoelectric element formation process)
In the piezoelectric element forming step, a rectangular piezoelectric base plate 121, an excitation electrode 122 provided on the upper and lower surfaces of the piezoelectric base plate 121, and an excitation electrode 122 are provided along one side of the piezoelectric base plate 121. The pair of lead-out electrodes 123 provided, the first recess 124 provided so that the piezoelectric base plate 121 is exposed on the upper surface of the pair of lead-out electrodes 123, and the piezoelectric base plate 121 exposed on the lower surface of the pair of lead-out electrodes 123 Forming a piezoelectric element 120 having a second recess 125 provided to

  A flat quartz wafer (not shown) is formed having crystal axes orthogonal to one another and composed of an X axis, a Y axis and a Z axis. As a quartz wafer, an artificial lens is used which has crystal axes orthogonal to one another, consisting of an X axis, a Y axis and a Z axis. The main surface of the quartz wafer is, for example, a plane parallel to the X axis and the Z axis, a predetermined angle counterclockwise as viewed in the negative direction of the X axis about the X axis, for example, about 37 It is parallel to the rotated plane. In addition, after the quartz wafer is cut from the artificial lens at a predetermined cut angle, both main surfaces are polished, and the thickness in the vertical direction becomes a predetermined thickness.

  Here, the quartz wafer is, for example, a flat plate having a substantially rectangular shape, and the dimension of a predetermined side in a plan view is 10.0 to 101.6 mm and is connected to the predetermined side. The size of one side is 10.0 to 101.6 mm. At this time, the thickness in the vertical direction of the crystal wafer is 0.020 to 0.070 mm. Although the case where the quartz wafer is a flat plate having a substantially rectangular shape is described, it may be a flat plate having a circular shape or an elliptical shape, and the size in plan view has a diameter of 10 It has become 0. 101.6 mm.

  The piezoelectric base plate 121 is fixed to a predetermined position of the quartz wafer at a predetermined side of the main surface of the portion to be the piezoelectric base plate 121 by photolithography technology and etching technology, and A portion to be the quartz crystal raw plate 121 in which the m-plane is formed on a part of the side surface is formed. First, a metal film is deposited on the entire surface of both main surfaces of a quartz wafer using a conventionally known photolithographic technique, a resist is applied on the metal film, and exposure and development are performed in a predetermined pattern. Thereafter, etching is performed by immersing the quartz wafer in a predetermined etching solution using a conventionally known etching technique. At this time, an m-plane parallel to the Z-axis can be easily formed on a part of the side surface of the portion to be the piezoelectric base plate 121 by utilizing the fact that the way of etching differs depending on the axial direction of the crystal axis.

  A metal film is deposited on the upper and lower surfaces of the piezoelectric base plate 121 to form an excitation electrode 122 and a lead-out electrode 123. When forming the excitation electrode 122 and the extraction electrode 123, the quartz wafer is deposited by evaporation or sputtering with the quartz wafer placed between a pair of masks in which through holes of a predetermined pattern are formed. A metal film is deposited at a predetermined position of a portion to be the piezoelectric element plate 121 of the quartz wafer in the space formed by the main surface and the surface facing the inside of the through hole. At this time, the first recess 124 is formed on the upper surface of the extraction electrode 123 by using a mask in which a part of the extraction electrode 123 is removed or the metal film is not deposited, and the lower surface of the extraction electrode 123 is formed. The second recess 125 is formed.

  Further, the opening area of the second recess 125 may be formed to be larger than the opening area of the first recess 124. In this way, even when the first recess 124 is formed, the area of the second recess 125 is larger than the area of the first recess 124 even if a slight positional deviation occurs. It can suppress that the two recessed parts 125 become non-overlapping. Therefore, it can be easily determined whether the outer peripheral edge of the conductive adhesive 140 is located in the second recess 125. Also, the opening of the first recess 124 or the second recess 125 is rectangular or circular.

  Further, the groove 126 is formed in the lead electrode 123 by removing a part of the lead electrode 123 or using a mask in which a metal film is not deposited on the side surface of the piezoelectric base plate 121. By forming the groove portion 126 in this manner, the first concave portion 124 and the second concave portion 125 are formed to be connected. By mounting the piezoelectric element 120 on the conductive adhesive 140 so that the position of the groove portion 126 and the position of the conductive adhesive 140 are aligned, the mounting accuracy of the piezoelectric element 120 can be further improved.

  Finally, a predetermined one side of the main surface of the portion to be the piezoelectric base plate 121 is broken or cut, and the portion to be the piezoelectric base plate 121 is singulated. In the crystal wafer 160, a portion to be the piezoelectric element plate 121 on which the excitation electrode 122 and the lead-out electrode 123 are formed is fixed on a predetermined side of the main surface of the portion to be the piezoelectric element plate 121. The piezoelectric element 120 is formed by breaking or cutting the fixed portion.

(Conductive adhesive application process)
The conductive adhesive applying step is a step of applying a conductive adhesive 140 on the electrode pad 111 provided on the package 110, as shown in FIG. 6 (b). The conductive adhesive 140 is applied to the upper surface of the electrode pad 111 by the first nozzle NZ1.

  First, as shown in FIG. 6A, the position of the electrode pad 111 in the accommodation space K of the package 110 is photographed by the first camera unit CA1 of the application means TS, and the image data is stored in the storage unit ME. When the electrode pad 111 is photographed by the first camera unit CA1 of the coating unit TS, the package 110 and the electrode pad 111 are not provided with the same material, so the position of the electrode pad 111 can be determined. Next, as shown in FIG. 6B, the first nozzle NZ1 of the coating unit TS is moved according to the position of the electrode pad 111, and the conductive adhesive 140 is applied. In addition, the first nozzle NZ1 can eject the conductive adhesive 140 by applying pressure and apply the conductive adhesive 140.

  The conductive adhesive 140 contains a conductive powder as a conductive filler in a binder such as silicone resin, and as the conductive powder, for example, aluminum (Al), molybdenum (Mo), tungsten ( W) platinum (Pt), palladium (Pd), silver (Ag), titanium (Ti), nickel (Ni), nickel iron (NiFe), or any combination thereof is used There is. The inner diameter of the first nozzle NZ1 appropriately corresponds to the particle size of the conductive powder.

(Piezoelectric element placement process)
In the piezoelectric element mounting step, as shown in FIG. 7A, the piezoelectric element 120 is conductively bonded such that the outer peripheral edge of the conductive adhesive 140 is positioned in the second recess 125 in plan view. It is a process of placing on the agent 140. First, as shown in FIG. 6C, the position of the conductive adhesive 140 formed on the electrode pad 111 is photographed by the second camera unit CA2 of the mounting means JS, and the image data is stored in the storage unit ME. When the conductive adhesive 140 is photographed by the second camera unit CA2 of the piezoelectric element mounting apparatus, the electrode pad 111 and the conductive adhesive 140 are not provided with the same material, so the position of the conductive adhesive 140 is Can be determined. The second nozzle NZ2 holding the piezoelectric element 120 is moved according to the position of the conductive adhesive 140, and the outer peripheral edge of the conductive adhesive 140 applied to the electrode pad 111 is the extraction electrode 123 of the piezoelectric element 120. The piezoelectric element 120 is placed on the conductive adhesive 140 so as to be located in the second recess 125 provided in

  After the piezoelectric element 120 is mounted, the second camera portion CA2 is photographed from the first concave portion 124 side, and the piezoelectric element 120 is formed of quartz crystal so that it is transmitted. It can be determined whether the outer peripheral edge is located in the second recess 125. By doing this, it is possible to determine whether the piezoelectric element 120 is pressed against the conductive adhesive 140 too much, so that the free end of the piezoelectric element 120 is in contact with the upper surface of the substrate 110 or the conductive adhesive 140 Since it is possible to sort the ones attached to the excitation electrode 122 before measuring the characteristics of the piezoelectric device, productivity can be improved.

(Piezoelectric element fixing process)
The piezoelectric element fixing step is a piezoelectric element fixing step of disposing the piezoelectric element 120 on the conductive adhesive 140 and curing the conductive adhesive 140, as shown in FIG. 7B. In the piezoelectric element fixing step, the piezoelectric element 120 is mounted on the conductive adhesive 140 so that the lead-out electrode 123 of the piezoelectric element 120 and the conductive adhesive 140 applied on the electrode pad 111 of the package 110 face each other. Place. Next, in a state where the package 110 is accommodated in the internal space of the curing annealing furnace in the air atmosphere or in the nitrogen atmosphere, the conductive adhesive 140 is heat-cured to electrically fix the electrode pad 111 and the piezoelectric element 120 together.

  The hardening annealing furnace (not shown) is comprised by the furnace main body, a heating part, a supply part, and a control part. The furnace body has an internal space and serves to store the package 110. The heating unit plays a role of heating the internal space to a predetermined temperature. For example, a halogen lamp, a xenon lamp or the like is used as the heating unit. The supply unit plays a role of supplying gas to the internal space. For example, nitrogen or the like is used as the gas. The control unit controls the temperature and oxygen concentration of the internal space of the furnace body, the temperature rising rate of the heating unit, and the gas supply amount of the supply unit.

(Lid joining process)
The lid bonding step is a step of bonding the lid 130 to the package 110 so as to hermetically seal the piezoelectric element 120, as shown in FIG. 7C. The lid 130 is made of, for example, an Fe-Ni alloy (42 alloy) or an Fe-Ni-Co alloy (Kovar), and is used when hermetically sealing the piezoelectric element 120 in a nitrogen gas atmosphere or a vacuum atmosphere. Be

  Specifically, when the bonding member 131 is glass, insulating resin or gold-tin, the lid 130 is provided on the surface of the frame 110 b of the package 110 in a nitrogen gas atmosphere or in a vacuum atmosphere. It is placed on the conductor pattern 113, and a heat source such as a halogen lamp is irradiated from the upper surface of the lid 130 to melt the bonding member 131, thereby bonding to the frame 110 b via the sealing conductor pattern 113.

  When the bonding member 131 is silver solder, the lid 130 is placed on the frame 110 b of the package 110 in a nitrogen gas atmosphere or a vacuum atmosphere, and the lid 130 is provided on the surface of the frame 110 b A roller electrode (not shown) of a seam welder (not shown) is brought into contact with the lid 130 so that the metal of the stopper conductor pattern 113 and the joining member 131 of the lid 130 are melted, and the roller electrode It is joined to the frame 110b by moving along the outer edge of the lid 130 while supplying power.

  In the method of manufacturing a piezoelectric device according to the present invention, a rectangular piezoelectric element plate 121, an excitation electrode 122 provided on the upper and lower surfaces of the piezoelectric element plate 121, and an excitation electrode 122 are provided. A pair of lead-out electrodes 123 provided along one side, a first recess 124 provided so that the piezoelectric base plate 121 is exposed on the upper surface of the pair of lead-out electrodes 123, and a piezoelectric element on the lower surface of the pair of lead-out electrodes 123 A piezoelectric element forming step of forming a piezoelectric element 120 having a second concave portion 125 provided so that the plate 121 is exposed, and conducting the conductive adhesive 140 applied on the electrode pad 111 provided on the package 110 And the piezoelectric element 120 is placed on the conductive adhesive 140 so that the outer peripheral edge of the conductive adhesive 140 is located in the second recess 125 in plan view. The package 110 and the lid are formed so as to hermetically seal the piezoelectric element 120 by sealing the piezoelectric element 120 by heat-curing the conductive adhesive 140 and thermally bonding the electrode pad 111 and the piezoelectric element 120. And a lid bonding step for bonding with 130. By doing this, it is possible to determine whether or not the piezoelectric element 1200 is pressed against the conductive adhesive 140 too much, so that the tip of the piezoelectric element 120 is in contact with the upper surface of the substrate 110 a or the conductive adhesive 140 is Since it is possible to sort out the one attached to the excitation electrode 122 before measuring the characteristics of the piezoelectric device, productivity can be improved.

  Further, in the method of manufacturing a piezoelectric device according to the present invention, the first recess 124 and the second recess 125 are formed so as to be connected at the side surface of the piezoelectric element plate 121 in the piezoelectric element forming step. Thus, the mounting accuracy of the piezoelectric element 120 is further improved by mounting the piezoelectric element 120 on the conductive adhesive 140 so that the position of the groove portion 126 and the position of the conductive adhesive 140 are aligned. be able to.

  In the piezoelectric device manufacturing method of the present invention, the opening area of the second recess 125 is formed to be larger than the opening area of the first recess 124 in the piezoelectric element forming step. In this way, even when the first recess 124 is formed, the area of the second recess 125 is larger than the area of the first recess 124 even if a slight positional deviation occurs. It can suppress that the two recessed parts 125 are arrange | positioned in the position which does not overlap. Therefore, it can be easily determined whether the outer peripheral edge of the conductive adhesive 140 is located in the second recess 125.

  The present invention is not limited to the present embodiment, and various changes, improvements, and the like can be made without departing from the scope of the present invention. Although the case where frame 110b was integrally formed with a ceramic material like substrate 110a was explained by the above-mentioned embodiment, frame 110b may be metal. In this case, the frame is joined to the conductor film of the substrate through a brazing material such as silver-copper. Moreover, although the case where the conductor pattern 113 for sealing was formed in the upper surface of the frame 110b was demonstrated in this embodiment, when the joining member 131 is glass or insulating resin, the conductor pattern for sealing is demonstrated. You may join to the frame 110b, without providing 113. FIG.

  In the above embodiment, the case where the frame 110b is provided on the upper surface of the substrate 110a has been described, but after the piezoelectric element is mounted on the substrate, the lid having the sealing frame provided on the lower surface of the sealing base is used. The structure may be such that the piezoelectric element is hermetically sealed by using it. The lid includes a rectangular sealing base and a sealing frame provided along the outer periphery of the lower surface of the sealing base, and the lower surface of the sealing base and the inner side of the sealing frame A housing space is formed by the side surface. The sealing frame portion is for forming an accommodation space on the lower surface of the sealing base. The sealing frame is provided along the outer edge of the lower surface of the sealing base.

  In the above embodiment, although the case where the piezoelectric element for AT was used was described, a tuning fork type having a quartz crystal base and two flat plate type quartz crystal vibrating portions extending in the same direction from the side surface of the quartz crystal base A bent piezoelectric element may be used. The piezoelectric element is composed of a piezoelectric element plate, an excitation electrode provided on the surface of the piezoelectric element plate, a lead-out electrode, and a metal film for frequency adjustment. The piezoelectric base plate comprises a quartz crystal base and a quartz oscillator, and the quartz oscillator comprises a first quartz oscillator and a second quartz oscillator. The quartz crystal base is an orthogonal coordinate system in which the electrical axis is X axis, the mechanical axis is Y axis, and the optical axis is Z axis as the crystal axis direction, within the range of -5 ° to + 5 ° around the X axis It is a flat plate having a substantially rectangular shape in plan view, in which the direction of the rotated Z 'axis is the thickness direction. The first quartz-crystal vibrating portion and the second quartz-crystal vibrating portion extend from one side of the quartz crystal base in parallel to the direction of the Y ′ axis. Such a piezoelectric element plate has a crystal base and crystal vibrating portions integrally formed into a tuning fork shape, and is manufactured by photolithography technology and chemical etching technology.

DESCRIPTION OF SYMBOLS 110 ... Package 110a ... Substrate 110b ... Frame 111 ... Electrode pad 112 ... External terminal 113 ... Conducting pattern 120 for sealing ... Piezoelectric element 121 ... Piezoelectric base plate 122: Excitation electrode 123: Extraction electrode 124: First concave portion 125: Second concave portion 130: Lid body 131: Bonding member 140: Conductive adhesive K · · ·・ Accommodation space

Claims (4)

A substrate,
An electrode pad provided on the upper surface of the substrate;
A conductive adhesive provided on the electrode pad;
A rectangular piezoelectric base plate, excitation electrodes provided on upper and lower surfaces of the piezoelectric base plate, and a pair of lead-out electrodes provided along one side of the piezoelectric base plate with a space between the excitation electrodes A first recess provided so as to expose the piezoelectric base plate on the upper surface of the pair of lead-out electrodes, and a second recess provided so that the piezoelectric base plate is exposed on the lower surface of the pair of lead-out electrodes And a piezoelectric element mounted on the electrode pad via the conductive adhesive,
A lid provided to hermetically seal the piezoelectric element;
The first concave portion and the second concave portion are provided at a position overlapping in plan view,
An outer peripheral edge of the conductive adhesive is provided in the second recess in plan view ,
The piezoelectric device wherein the opening area of the second recess is larger than the opening area of the first recess . The piezoelectric device according to claim 1, wherein
A piezoelectric device, wherein the first concave portion and the second concave portion are connected at a side surface of the piezoelectric base plate. A rectangular piezoelectric base plate, excitation electrodes provided on upper and lower surfaces of the piezoelectric base plate, and a pair of lead-out electrodes provided along one side of the piezoelectric base plate with a space between the excitation electrodes A first recess provided so as to expose the piezoelectric base plate on the upper surface of the pair of lead-out electrodes, and a second recess provided so that the piezoelectric base plate is exposed on the lower surface of the pair of lead-out electrodes Forming a piezoelectric element such that the opening area of the second recess is larger than the opening area of the first recess;
A conductive adhesive applying step of applying a conductive adhesive on an electrode pad provided on the package;
A piezoelectric element mounting step of mounting the piezoelectric element on the conductive adhesive such that the outer peripheral edge of the conductive adhesive is located in the second recess in plan view;
A piezoelectric element fixing step of heating and curing the conductive adhesive to electrically fix the electrode pad and the piezoelectric element;
A lid bonding step of bonding a lid to the package so as to hermetically seal the piezoelectric element. A method of manufacturing a piezoelectric device according to claim 3, wherein
In the piezoelectric element forming step,
A method of manufacturing a piezoelectric device, wherein the first concave portion and the second concave portion are formed to be connected with the side surface of the piezoelectric base plate.

Images