JP2013251673A - Crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal device in which a small crystal element can be mounted.SOLUTION: The crystal device includes a rectangular substrate 110a having a mounting region R1 in center and peripheral regions R2 on both sides of the mounting region R1, a conductive adhesive agent DS provided in one peripheral region R2 of the substrate 110a, as a polygonal recess 113 in plan view, and having a width along one side of the substrate 110a corresponding to one peripheral region R2 that decreases from one peripheral region R2 toward the mounting region R1 and having a top on the central side, and a crystal element 120 connected onto the conductive adhesive agent DS so as to be superimposed from the top across the mounting region R1.

Description

  The present invention relates to a crystal device used in, for example, an electronic apparatus.

  A conventional quartz device uses a piezoelectric effect of a quartz element to cause a thickness-shear vibration so that both surfaces of a quartz base plate are displaced from each other, thereby generating a specific frequency. At present, a quartz crystal device including a quartz crystal element mounted on an electrode pad provided on a substrate has been proposed (for example, see Patent Document 1 below). The crystal element has excitation electrodes on both main surfaces of the crystal base plate, one end of the crystal element is a fixed end connected to the upper surface of the substrate, and the other end is a free end spaced from the upper surface of the substrate. This is a piece holding structure.

JP 2002-111435 A

  The above-described quartz device is remarkably miniaturized, but the quartz element mounted on the package is also downsized. When a crystal element is bonded with a size of a conventional conductive adhesive applied diameter, the bonding area between the crystal element and the conductive adhesive increases, so that the excitation electrode and the conductive adhesive may come into contact with each other. .

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a crystal device capable of mounting a small crystal element.

  A quartz crystal device according to an aspect of the present invention has a rectangular shape, has a mounting area in the center, has a peripheral area on both sides of the mounting area, and is provided on one of the peripheral areas of the substrate, and is viewed in plan view. A conductive adhesive having a polygonal shape, the width in the direction along one side of the substrate corresponding to one of the peripheral regions is small from one of the peripheral regions toward the mounting region, and a top portion on the central side. And a crystal element connected on the conductive adhesive so as to overlap from the top to the mounting region.

A quartz crystal device according to one aspect of the present invention includes a quartz crystal element connected so as to overlap from the top of a polygonal conductive adhesive to a mounting region, thereby allowing a contact area between the quartz crystal element and the conductive adhesive. This makes it possible to mount a small crystal element.

It is a disassembled perspective view which shows the crystal device in 1st embodiment. It is sectional drawing in AA of the quartz crystal device shown by FIG. (A) It is a top view which shows the state which removed the cover of the crystal device in 1st embodiment, (b) The top view which shows the state which removed the cover and crystal element of the crystal device in 1st embodiment. . (A) It is a top view which shows the state which removed the cover of the crystal device in the modification of 1st embodiment, (b) The state which removed the cover and crystal element of the crystal device in the modification of 1st embodiment FIG. (A) It is a top view which shows the state which removed the cover of the crystal device in 2nd embodiment, (b) It is a top view which shows the state which removed the cover and crystal element of the crystal device in 2nd embodiment. . (A) It is a top view which shows the state which removed the cover of the crystal device in 3rd embodiment, (b) It is a top view which shows the state which removed the cover and crystal element of the crystal device in 3rd embodiment. .

(First embodiment)
As shown in FIGS. 1 and 2, the crystal device in the first embodiment includes a package 110 and a crystal element 120 bonded to a substrate 110 a of the package 110. The package 110 has an accommodation space K surrounded by the upper surface of the substrate 110a and the inner surface of the frame 110b.

The substrate 110a has a rectangular shape and functions as a support member for supporting the crystal element 120 mounted on the upper surface.
The substrate 110a has a mounting region R1 in the center and peripheral regions R2 on both sides of the mounting region R1. A pair of electrode pads 111 for bonding the crystal element 120 are provided on the upper surface of the substrate 110a. In addition, external connection electrode terminals G are provided at the four corners of the lower surface of the substrate 110a.

  The substrate 110a is made of an insulating layer made of a ceramic material such as alumina ceramic or glass-ceramic. The substrate 110a may be one using one insulating layer or may be a laminate of a plurality of insulating layers. A wiring pattern (not shown) and a via conductor (not shown) for electrically connecting the pair of electrode pads 111 on the upper surface of the substrate 110a and the external connection electrode terminals G on the lower surface are provided on and inside the substrate 110a. Z).

  The frame 110b is for forming the accommodation space K on the substrate 110a. The frame 110b is made of a ceramic material such as alumina ceramics or glass-ceramics, and is formed integrally with the substrate 110a. A sealing conductor pattern 112 is provided on the upper surface of the frame 110b.

  The sealing conductor pattern 112 plays a role of improving the wettability of the sealing member 131 when it is bonded to the lid 130 via the sealing member 131. The sealing conductor pattern 112 is connected to at least one external connection electrode terminal G by a via conductor (not shown) and a wiring pattern (not shown) formed in the substrate 110a. The at least one external connection electrode terminal G serves as a ground terminal by being connected to a mounting pad connected to the ground on the external mounting substrate. Therefore, the lid 130 joined to the sealing conductor pattern 112 is connected to the ground, and the shielding performance in the recess K1 by the lid 130 is improved. The sealing conductor pattern 112 is formed to have a thickness of, for example, 10 μm to 25 μm by sequentially applying nickel plating and gold plating to the surface of the conductor pattern made of tungsten, molybdenum, or the like in a manner surrounding the upper surface of the frame 110b in an annular shape. Has been.

  The recess 113 is provided in the pair of electrode pads 111 as shown in FIG. 1 and FIG. Moreover, the shape of the recessed part 113 when planarly viewed is a polygonal shape, and an example thereof is a triangular shape as shown in FIG. The conductive adhesive DS is provided in a triangular shape along each wall surface in the recess 113. Moreover, each top part of the conductive adhesive DS is provided with roundness due to surface tension. The conductive adhesive DS is provided so as to rise from the opening surface of the recess 113. The conductive adhesive DS at the top portion facing the mounting region R1 is raised about 30 to 50 μm from the opening surface, and the conductive adhesive DS at the two top portions facing the peripheral region R2 side is opened. About 10 to 25 μm is raised from the surface.

  Here, the size of the recess 113 will be described by taking as an example a case where the vertical dimension when the package 110 is viewed in plan is 1.6 mm and the horizontal dimension when viewed in plan is 1.2 mm. The base of the triangle of the opening surface of the recess 113 is parallel to the short side of the substrate 110a. The length of the triangular base of the opening surface of the recess 113 shown in FIG. 3B is about 150 to 200 μm, and the height of the triangle that is the opening surface of the recess 113 is about 150 to 200 μm. It is. The length of the concave portion 113 in the vertical direction is about 10 to 40 μm.

  The recess 113 is formed by forming a resist mask on the electrode pad 111, removing a part of the electrode pad 111 by etching, and removing the resist mask.

  In addition, an R shape is provided at each top of the recess 113. By providing the R shape at the top as described above, the stress applied to each top can be dispersed, and peeling of the electrode pad 111 can be reduced. By reducing the peeling of the electrode pad 111, the crystal element 120 can stably output an oscillation frequency.

  The conductive adhesive DS is provided on one side of the peripheral region R2 of the substrate 110a and has a polygonal shape in plan view. An example of the shape of the conductive adhesive DS is a triangular shape as shown in FIG. In addition, the triangular conductive adhesive DS has a width in the direction along one side of the substrate 110a corresponding to one of the peripheral regions R2 that decreases from one of the peripheral regions R2 toward the mounting region R1, and is closer to the center side. It has a top.

  Further, since the conductive adhesive DS spreads toward the two top portions provided toward the peripheral region R2 of the recess 113, it is possible to reduce spreading between the crystal element 120 and the electrode pad 111. .

  Here, a method for manufacturing the package 110 will be described. When the substrate 110a and the frame 110b are made of alumina ceramics, 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 is prepared. In addition, a predetermined conductor paste is applied to the surface of the ceramic green sheet or a through-hole previously punched by punching the ceramic green sheet by screen printing or the like. Further, these green sheets are laminated and press-molded and fired at a high temperature. Finally, it is produced by applying nickel plating or gold plating to a predetermined portion of the conductor pattern, specifically, a portion to be the pair of electrode pads 111 or the external connection electrode terminal G. Moreover, the conductor paste is comprised from the sintered compact etc. of metal powders, such as tungsten, molybdenum, copper, silver, or silver palladium, for example.

  As shown in FIG. 2, the crystal element 120 is bonded onto the electrode pad 111 on the substrate 110a via the conductive adhesive DS. The crystal element 120 plays a role of oscillating a reference signal of an electronic device or the like by stable mechanical vibration and a piezoelectric effect.

  As shown in FIG. 2, the crystal element 120 has a structure in which the excitation electrode 122, the connection electrode 123, and the extraction electrode 124 are attached to the upper surface and the lower surface of the crystal base plate 121, respectively. . The excitation electrode 122 is formed by depositing and forming a metal in a predetermined pattern on each of the upper surface and the lower surface of the quartz base plate 121. The extraction electrode 124 extends from the excitation electrode 122 toward the short side of the crystal base plate 121. The connection electrode 123 is connected to the lead electrode 124 and is provided in a shape along the long side or the short side of the crystal base plate 121.

  The crystal element 120 is provided on the conductive adhesive DS so as to overlap the mounting region R1 from the top portion facing the mounting region R1 of the substrate 110a. In the present embodiment, the one-side holding structure in which one end of the crystal element 120 connected to the electrode pad 111 is a fixed end connected to the upper surface of the substrate 110 and the other end is a free end spaced from the upper surface of the substrate 110. The quartz crystal element 120 is fixed on the substrate 110a.

  As shown in FIG. 3A, the outer peripheral edge of the quartz base plate 121 is provided so as to pass through the center of gravity P of the triangular recess 113 and to be parallel to the short side of the substrate 110a. It is provided so as to be positioned on the top side with respect to the line segment CL. The conductive adhesive DS at the top portion facing the mounting region R1 is in contact with the connection electrode 123 of the crystal element 120, and the conductive adhesives at the two top portions facing the peripheral region R2 side. The distance between the DS and the outer peripheral edge on the fixed end side of the crystal element is about 5 to 45 μm. By doing so, the contact area between the crystal element 120 and the conductive adhesive DS can be reduced, and the crystal impedance value of the crystal element 120 can be reduced.

  Here, the operation of the crystal element 120 will be described. When an alternating voltage from the outside is applied to the crystal element plate 121 from the connection electrode 123 via the extraction electrode 124 and the excitation electrode 122, the crystal element 120 is excited in a predetermined vibration mode and frequency. Is supposed to wake up.

  Here, a manufacturing method of the crystal element 120 will be described. First, the crystal element 120 is cut from the artificial crystalline lens at a predetermined cut angle to reduce the thickness of the outer periphery of the crystal base plate 121, and the central portion of the crystal base plate 121 is thicker than the outer peripheral portion of the crystal base plate 121. The bevel processing provided is performed. Then, the quartz crystal element 120 has the excitation electrode 122, the connection electrode 123, and the extraction electrode 124 formed by depositing a metal film on both main surfaces of the quartz base plate 121 by a photolithography technique, a vapor deposition technique, or a sputtering technique. It is produced by forming.

  A method for bonding the crystal element 120 to the substrate 110 will be described. First, the conductive adhesive DS is applied into the triangular recess 113 of the pair of electrode pads 111 by, for example, a dispenser. At this time, since the conductive adhesive DS spreads along the wall of the triangular recess 113, it has a triangular outer shape. The conductive adhesive DS is provided so as to rise from the opening surface of the triangular recess 113. Then, the crystal element 120 is conveyed onto the top of the triangular conductive adhesive DS. Further, the crystal element 120 has an outer peripheral edge on the fixed end side of the crystal element plate 121 with respect to a line segment that passes through the center of gravity P of the triangular recess 113 and is parallel to the short side of the substrate 110a. The conductive adhesive DS is placed on the triangular top so as to be located on the top side. The crystal element 120 is bonded to the pair of electrode pads 111 by heating and curing the conductive adhesive DS.

  The conductive adhesive DS contains a conductive powder as a conductive filler in a binder such as a silicone resin. Examples of the conductive powder include aluminum, molybdenum, tungsten, platinum, palladium, silver, titanium, One containing either nickel or nickel iron, or a combination thereof is used. Moreover, as a binder, a silicone resin, an epoxy resin, a polyimide resin, or a bismaleimide resin is used, for example.

  The lid 130 is made of an alloy containing at least one of iron, nickel, and cobalt, for example. Such a lid 130 is for hermetically 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 frame 110b of the package 110 in a predetermined atmosphere, and the sealing conductor pattern 112 of the frame 110b and the sealing member 131 of the lid 130 are welded. As described above, by applying a predetermined current and performing seam welding, the frame body 110b is joined.

  The sealing member 131 is provided at a position of the lid 130 facing the sealing conductor pattern 112 provided on the upper surface of the frame 110 b of the package 110. The sealing member 131 is provided by, for example, silver solder or gold tin.

  The crystal device in the first embodiment includes the crystal element 120 and the conductive adhesive DS that are connected to the conductive adhesive DS so as to overlap the mounting region 115 from the top. The contact area between the conductive adhesive DS and the excitation electrode 122 is reduced, so that the small crystal element 120 can be mounted.

(Modification)
Hereinafter, a crystal device according to a modification of the first embodiment will be described. Note that, in the quartz crystal device according to the first embodiment, portions similar to those of the quartz crystal device described above are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  As shown in FIG. 4, the recess 113 is provided in the pair of electrode pads 111. In addition, the shape of the recess 113 when viewed from above is a right triangle. The conductive adhesive DS is provided in a right triangle shape along each wall surface in the recess 113. Moreover, each top part in the recessed part 113 of right-angled triangle shape is provided with roundness for the surface tension of the electroconductive adhesive DS. The conductive adhesive DS is provided so as to rise from the opening surface of the recess 113.

  In the quartz crystal device according to the first embodiment, two conductive adhesives DS are provided on one side of the peripheral region R2, and the pair of conductive adhesives DS has a right triangle shape in plan view, and the pair of conductive adhesives Since the tops of the adhesives DS are arranged close to each other, the contact area between the crystal element 120 and the conductive adhesive DS is reduced, and the crystal impedance value of the crystal element 120 can be reduced. In addition, since the conductive adhesive DS does not overflow from the recess 113 in the quartz device, it is possible to reduce the short circuit between adjacent conductive adhesives. In addition, since the interval between the conductive adhesives DS can be shortened in the quartz device, a further small quartz element 120 can be mounted.

(Second embodiment)
Hereinafter, the crystal device according to the second embodiment will be described. In addition, about the quartz crystal device in 2nd embodiment, about the part similar to the crystal device mentioned above, the same code | symbol is attached | subjected and description is abbreviate | omitted suitably.

  As shown in FIG. 5, the quartz crystal device according to the second embodiment is different from the first embodiment in that a trapezoidal conductive adhesive DS is provided.

  The recess 213 is provided in the pair of electrode pads 211 as shown in FIG. Moreover, the shape of the recessed part 213 when the package 210 which comprises the piezoelectric device in this embodiment is planarly viewed has a trapezoidal shape as shown in FIG.5 (b). Since the conductive adhesive DS is formed along each wall surface in the recess 213, the conductive adhesive DS is provided in a trapezoidal shape. The conductive adhesive DS at the two top portions facing the mounting region R1 is raised about 30 to 50 μm from the opening surface, and the conductive adhesive DS at the two top portions facing the peripheral region R2 side. Is raised from the opening surface by about 10 to 25 μm.

  Here, the size of the recess 213 will be described by taking as an example a case where the vertical dimension of the package 210 in plan view is 1.6 mm and the horizontal dimension in plan view is 1.2 mm. The trapezoidal upper and lower bases of the opening surface of the recess 213 are parallel to the short side of the substrate 210a. The length of the upper base of the trapezoid of the opening surface of the recessed part 213 shown in FIG. 5 is about 10-50 micrometers, and the length of the lower base of the trapezoid of the opening surface of the recessed part 213 is about 150-200 micrometers. Moreover, the height of the trapezoid which is the opening surface of the recessed part 213 is about 150-200 micrometers. Moreover, the length of the up-down direction of the recessed part 213 is about 10-40 micrometers.

  The crystal element 120 is provided on the conductive adhesive DS so as to overlap the mounting region R1 from the two tops facing the mounting region R1 of the substrate 210a. The crystal element 120 is bonded to the electrode pad 211 via the two tops of the conductive adhesive DS.

  In the crystal device according to the second embodiment, the conductive adhesive DS has a trapezoidal shape, and since the two top portions facing the mounting region R1 and the crystal element 120 are connected, the conductive adhesive DS is heated. Is applied, the thermal stress is distributed to the two tops, so that the connection strength between the conductive adhesive DS and the crystal element 120 is improved. Therefore, the oscillation frequency of the crystal element 120 can be output stably.

(Third embodiment)
Hereinafter, the crystal device according to the third embodiment will be described. Note that, in the quartz crystal device according to the third embodiment, portions similar to those of the quartz crystal device described above are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  In the crystal device according to the third embodiment, as shown in FIG. 6, one conductive adhesive DS is provided in each of the peripheral regions R2, and the top of the pair of conductive adhesives DS is provided. They differ from the first embodiment in that they are arranged on the mounting region R1 side.

  The package 310 includes a substrate 310a and a frame 310b. As shown in FIG. 6B, the substrate 310a has a mounting region R1 at the center and peripheral regions R2 on both sides of the mounting region R1.

  The first electrode pad 311a is provided along one side of the peripheral region R2, and the second electrode pad 311b is provided along one side of the opposing peripheral region R2.

  As shown in FIG. 6, the recess 313 is provided in the first electrode pad 311a and the second electrode pad 311b. The shape of the recess 313 when viewed in plan is a triangular shape. The conductive adhesive DS is provided in a triangular shape along each wall surface in the recess 313. In addition, one corner of the triangular recess 313 is provided while being rounded due to the surface tension of the conductive adhesive DS.

  As shown in FIG. 6B, the crystal element 220 has a structure in which the excitation electrode 222, the connection electrode 223, and the extraction electrode 224 are attached to the upper and lower surfaces of the crystal base plate 221, respectively. doing. The excitation electrode 222 is formed by depositing and forming a metal in a predetermined pattern on each of the upper and lower surfaces of the quartz base plate 221. The extraction electrode 224 extends from the excitation electrode 222 toward each short side of the crystal base plate 221. The connection electrodes 223 are connected to the extraction electrodes 224 and are provided one by one in a shape along the short side of the crystal base plate 221.

  The crystal element 220 is connected to a pair of top portions facing the mounting region R1 of the substrate 310a on the conductive adhesive DS. The quartz crystal element 120 is joined to the electrode pad 311 through the tops of the conductive adhesives DS that are respectively provided in both of the peripheral regions R2.

  As shown in FIG. 6A, one outer peripheral edge of the quartz base plate 221 is a line provided so as to pass through the center of gravity P of the triangular recess 213 and to be parallel to the short side of the substrate 310a. It is provided so as to be located on the top side with respect to the minute CL1. Similarly, the other outer peripheral edge of the quartz base plate 221 is positioned on the apex side with respect to the line segment CL2 provided so as to pass through the center of gravity P of the triangular recess 313 and to be parallel to the short side of the substrate 310a. It is provided to do.

  In the third embodiment, the crystal element 220 is fixed on the substrate 310a by a holding structure in which both ends of the crystal element 220 connected to the electrode pad 311 are fixed to the upper surface of the substrate 310a.

  The quartz crystal device according to the third embodiment has the conductive adhesive D that is provided on each of the peripheral regions R2, and the tops of the pair of conductive adhesives DS are on the mounting region R1 side. By being arranged, the quartz base plate 221 can be held at both ends. Therefore, when a drop test or the like is performed, the stress applied to the crystal element 220 is equally applied to both ends of the crystal base plate 221, so that the crystal element 220 can be prevented from being peeled off from the electrode pad 311.

  The quartz crystal device according to the modification of the third embodiment is provided so that the tops of the pair of conductive adhesives DS face each other on a diagonal line. The crystal element 220 and the electrode pad 311 can be electrically connected if the crystal element 220 overlaps at least the tops of the pair of conductive adhesives DS in plan view. Thus, by arranging the tops of the pair of conductive adhesives DS so as to be close to the center of the substrate, the crystal element 220 that can be connected to the pair of conductive adhesives DS can be further downsized. By doing so, the quartz crystal device can mount the smaller quartz crystal element 220 on the substrate 310a of the package 310.

  In addition, it is not limited to this embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention. In the modification of the first embodiment described above, the case where the frame 110b is integrally formed of a ceramic material like the substrate 110a has been described. However, the frame 110b may be made of metal. In this case, the frame is joined to the conductor film of the substrate via a brazing material such as silver-copper.

  In the above embodiment, the case where an AT crystal element is used as the crystal element has been described. However, a tuning fork-type bent crystal having a base and two flat plate-shaped vibrating arms extending in the same direction from the side surface of the base. An element may be used.

  In the above embodiment, the case where the bevel processing is used for the crystal element has been described. However, the thickness of the outer periphery of the crystal element plate 121 is reduced, and the center of the crystal element plate 121 is compared with the outer periphery of the crystal element plate 121. You may use the bevel process provided so that a part may become thick. A bevel processing method for the crystal element 120 will be described. A polishing material provided with media and abrasive grains having a predetermined particle size and a quartz base plate 121 having a predetermined size are prepared. The abrasive prepared in the cylindrical body and the quartz base plate 121 are placed, and the open end of the cylindrical body is closed with a cover. The quartz base plate 121 that rotates the cylindrical body containing the abrasive and the quartz base plate 121 with the central axis of the cylindrical body as the rotation axis is polished with the abrasive and beveled.

110, 210, 310 ... Package 110a, 210a, 310a ... Substrate 110b, 210b, 310b ... Frame 111, 211, 311 ... Electrode pad 112 ... Sealing conductor pattern 113, 213 313: Recessed portion 120, 220 ... Quartz element 121, 221 ... Crystal base plate 122, 222 ... Excitation electrode 123, 223 ... Connection electrode 124, 224 ... Lead electrode 130 ... Lid 131 ... Sealing member K ... Storage space DS ... Conductive adhesive G ... External connection terminal R1 ... Mounting area R2 ... Peripheral area

Claims (4)

A substrate having a rectangular shape and having a mounting region in the center, and peripheral regions on both sides of the mounting region;
Provided in one of the peripheral regions of the substrate and having a polygonal shape in plan view, the width in a direction along one side of the substrate corresponding to one of the peripheral regions is from one of the peripheral regions to the mounting A conductive adhesive that is small toward the region and has a top on the center side;
A quartz crystal device comprising: a quartz crystal element connected on the conductive adhesive so as to overlap from the top to the mounting region. The crystal device according to claim 1,
A quartz crystal device, wherein the conductive adhesive has a triangular shape in plan view. The crystal device according to claim 2,
Two conductive adhesives are provided on one of the peripheral areas;
A pair of said conductive adhesives are right-angled triangle shape by planar view, Comprising: Each top part of a pair of said conductive adhesives is arrange | positioned adjacently, The quartz crystal device characterized by the above-mentioned. The crystal device according to claim 2,
Each of the conductive adhesives is provided on each of the peripheral regions,
The tops of the pair of conductive adhesives are arranged on the mounting region side, respectively.

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