JP2014225837A - Crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal resonator which inhibits a gas occurring from a joint member from adhering to a crystal element to thereby reduce fluctuations of the oscillatory frequency of the crystal element.SOLUTION: A crystal resonator includes: a substrate 110; a crystal element 120 mounted on the substrate 110; and a sealing lid body 130 which is provided on the substrate 110, has an outer edge formed into a rectangular shape when planarly viewed, and covers the crystal element 120 in a sealing manner. In the sealing lid body 130, a recessed part 131 cut out from an outer side surface to a lower surface is formed. The lower surface of the sealing lid body 130 contacts with an upper surface of the substrate 110, and a joint member 150 is provided at an area ranging from the recessed part 131 onto the substrate 110.

Description

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

  The crystal device generates a specific frequency by using the piezoelectric effect of the crystal element. For example, a crystal resonator including a crystal element mounted on an electrode pad provided on an upper surface of a substrate, and a lid that is bonded to the upper surface of the substrate via a bonding member and hermetically seals the crystal element. Has been proposed (see, for example, Patent Document 1 below). Glass is used for the bonding member, and by applying heat, the lower surface of the lid and the upper surface of the substrate can be bonded.

JP 2009-141234 A

  In the crystal device described above, the lid and the substrate are bonded via the bonding member, so that the gas generated from the bonding member adheres to the crystal element. When the gas adheres to the crystal element, the thickness-shear vibration of the crystal element is hindered and the oscillation frequency of the crystal element may fluctuate.

  The present invention has been made in view of the above problems, and provides a crystal device capable of suppressing the gas generated from the bonding member from adhering to the crystal element and reducing the fluctuation of the oscillation frequency of the crystal element. The purpose is to do.

  A quartz crystal device according to one aspect of the present invention includes a substrate, a quartz crystal element mounted on the substrate, a quartz element provided on the substrate, and having a rectangular outer edge when viewed in plan so that the quartz crystal element is sealed. A sealing lid body, and the sealing lid body has a recess formed by cutting from the outer surface to the lower surface in the recess, and the lower surface of the sealing lid body is in contact with the upper surface of the substrate A bonding member is provided from the inside of the recess to the top of the substrate.

  In the quartz crystal device according to one aspect of the present invention, the sealing lid has a recess formed by cutting from the outer surface to the lower surface, and the lower surface of the sealing lid contacts the upper surface of the substrate and from within the recess. A joining member is provided over the substrate. By doing in this way, since the gas generated from the joining member is blocked by the inner peripheral side surface of the concave portion of the lid, it is difficult to adhere to the crystal element. Therefore, the quartz crystal device suppresses the gas from adhering to the quartz crystal element, and the thickness-shear vibration of the quartz crystal element is not hindered, so that the fluctuation of the oscillation frequency of the quartz crystal element can be reduced.

It is a disassembled perspective view which shows the crystal device in this embodiment. It is sectional drawing in AA of the quartz crystal device shown by FIG. It is sectional drawing of the quartz crystal device in the 1st modification of this embodiment. It is a disassembled perspective view which shows the quartz crystal device in the 2nd modification of this embodiment. It is sectional drawing in BB of the crystal device shown by FIG.

  As shown in FIGS. 1 and 2, the crystal device according to the present embodiment includes a substrate 110, a crystal element 120 bonded to the upper surface of the substrate 110, and a seal for hermetically sealing the crystal element 120. A lid 130. Such a crystal resonator is used to output a reference signal used in an electronic device or the like.

  The substrate 110 has a rectangular shape and functions as a mounting member for mounting the crystal element 120 mounted on the upper surface. Electrode pads 111 for bonding the crystal element 120 are provided on the upper surface of the substrate 110, and external terminals G are provided at the four corners of the lower surface of the substrate 110.

  The substrate 110 is made of an insulating layer made of a ceramic material such as alumina ceramic or glass-ceramic. The substrate 110 may be one using an insulating layer or may be a laminate of a plurality of insulating layers. On the surface and inside of the substrate 110, wiring patterns and via conductors for electrically connecting the electrode pads 111 provided on the upper surface and the external terminals G on the lower surface are provided.

  The electrode pad 111 is for mounting the crystal element 120. A pair of electrode pads 111 are provided on the upper surface of the substrate 110, and are provided adjacent to each other along one side of the substrate 110. The electrode pad 111 is electrically connected to one of the external terminals G provided on the lower surface of the substrate 110 via a wiring pattern and a via conductor provided on the substrate 110. The external terminals G are provided at the four corners of the lower surface of the substrate 110 along the outer peripheral edge of the substrate 110. The external terminal G is used for bonding via solder when mounted on the mother board.

  Here, a method for manufacturing the substrate 110 is described. When the substrate 110 is 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 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 manufactured by applying nickel plating, gold plating, or the like to a predetermined portion of the conductor pattern, specifically, a portion to be the pair of electrode pads 111 or the external 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 via a conductive adhesive 140. 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 FIGS. 1 and 2, the crystal element 120 has a structure in which an excitation electrode 122, a connection electrode 123, and an extraction electrode 124 are attached to the upper and lower surfaces of a crystal base plate 121, respectively. doing. 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.

  In the present embodiment, 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 cantilever support having a free end spaced from the upper surface of the substrate 110. The crystal element 120 is fixed on the substrate 110 by the structure. 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 140 is applied onto the electrode pad 111 by, for example, a dispenser. The crystal element 120 is transported onto the conductive adhesive 140 and placed on the conductive adhesive 140. The conductive adhesive 140 is cured and contracted by being heated and cured. The crystal element 120 is bonded to the pair of electrode pads 111.

  The conductive adhesive 140 contains conductive powder as a conductive filler in a binder such as silicone resin, and the conductive powder includes 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 sealing lid 130 includes a rectangular sealing base portion 130a and a sealing frame portion 130b, and an accommodation space K is formed by the lower surface of the sealing base portion 130a and the inner side surface of the sealing frame portion 130b. Has been. The sealing frame part 130b is for forming the accommodation space K on the lower surface of the sealing base part 130a. The sealing frame part 130b is provided along the outer edge of the lower surface of the sealing base part 130a.

  The sealing base portion 130a and the sealing frame portion 130b are made of, for example, an alloy containing at least one of iron, nickel, and cobalt, and are integrally formed. Such a sealing lid 130 is for hermetically sealing the housing space K in a vacuum state or the housing space K filled with nitrogen gas or the like. Specifically, the sealing lid 130 is placed on the upper surface of the substrate 110 in a predetermined atmosphere, and the upper surface of the substrate 110 and the bonding member 150 provided in the recess 131 of the sealing lid 130 are heated. By being applied, fusion bonding is performed.

  The recess 131 is provided so as to be cut out from the outer surface to the lower surface of the sealing frame portion 130 b of the sealing lid 130. By doing so, the gas generated from the joining member 150 is blocked by the inner side surface of the recess 131 of the sealing lid 130, so that it enters the accommodation space K of the sealing lid 130. Can be reduced. Therefore, the hermetic sealability in the accommodation space K can be improved. In addition, the gas generated from the bonding member 150 is less likely to adhere to the crystal element 120 mounted in the accommodation space K. Therefore, since the thickness shear vibration of the crystal element 120 is not hindered, it is possible to reduce fluctuations in the oscillation frequency of the crystal element 120.

  Further, the recess 131 is formed continuously along the outer edge of the sealing lid 130. By doing in this way, the inside of the recessed part 131 of the sealing lid body 130 and the upper surface of the board | substrate 110 can be reliably joined by the joining member 150 so that the inside of the storage space K may be enclosed. Therefore, the hermetic sealing performance in the accommodation space K of the sealing lid 130 can be further improved.

  Here, the dimension of one side when the sealing lid 130 is viewed in plan is 1.0 to 3.0 mm, the dimension in the thickness direction of the sealing lid 130 is 0.2 to 0.4 mm, The magnitude | size of the recessed part 131 is demonstrated to the case where the space | interval of the inner surface of the sealing frame part 130b and an outer surface is 0.15-0.30 mm as an example. The distance between the outer edge of the recess 131 and the inner surface of the recess 131 is 0.015 to 0.270 mm. The length of the recess 131 in the depth direction is 0.05 to 0.20 mm.

  The joining member 150 is provided from the inside of the recess 131 to the substrate 110. For example, in the case of glass, the bonding member 150 is made of low-melting glass containing, for example, vanadium, which is a lead-free glass that melts at 350 ° C. to 400 ° C. Lead-free glass is in the form of a paste with a binder and a solvent added, and after being melted and solidified, it adheres to other members. The joining member 150 is provided, for example, by applying a glass frit paste by a screen printing method and drying it.

  For example, in the case of an insulating resin, the bonding member 150 is made of an epoxy resin or a polyimide resin. The thickness of the joining member 150 provided in the recess 131 is 40 μm to 125 μm, and the thickness of the joining member 150 provided between the frame 110 b and the lid 130 is 30 to 100 μm. Yes.

  For example, when the joining member 150 is gold tin, the thickness of the layer of the joining member 150 is 10 to 40 μm. For example, the component ratio is 70 to 80% for gold and 20 to 30% for tin. May be used. For example, when the joining member 150 is silver brazing, the thickness of the layer of the joining member 150 is 10 to 40 μm. For example, the component ratio is 70 to 80% for silver and 20 to 30% for copper. May be used.

  The notch 132 is provided so as to penetrate vertically in at least one of the four corners of the sealing lid 130 in plan view. Moreover, the length of the notch part 132 in the vertical direction is 0.2 to 0.4 mm. The notch 132 is provided so as to penetrate in at least one of the four corners of the sealing base 130 a and the sealing frame 130 b in a plan view, and is provided so as to be connected to the recess 131. Therefore, when the sealing lid 130 and the substrate 110 are joined by the joining member 150, the melted joining member 150 is joined so as to scoop up the outer surface of the notch 132. The bonding strength between the sealing lid body 130 and the sealing lid body 130 can be improved.

  In addition, the notch 132 allows the gas generated from the molten joining member 150 to escape upward when the sealing lid 130 and the substrate 110 are joined by the joining member 150. It is possible to further reduce the adhesion of gas generated from the bonding member 150 to the crystal element 120. Therefore, since the thickness shear vibration of the crystal element 120 is not hindered, it is possible to further reduce the fluctuation of the oscillation frequency of the crystal element 120.

  In the quartz crystal device according to the present embodiment, a recess 131 is formed in the sealing lid 130 from the outer surface to the lower surface. The lower surface of the sealing lid 130 contacts the upper surface of the substrate 110 and the recess 131. A joining member 150 is provided from the inside to the substrate 110. By doing in this way, since the gas generated from the joining member 150 is blocked by the inner side surface of the recess 131 of the sealing lid body 130, the generated gas enters the housing space K of the sealing lid body 130. Can be reduced. Therefore, the gas generated from the bonding member 150 is less likely to adhere to the crystal element 120 mounted in the accommodation space K. Such a crystal device suppresses the gas generated from the bonding member 150 from adhering to the crystal element 120, and the thickness-shear vibration of the crystal element 120 is not hindered, thereby reducing fluctuations in the oscillation frequency of the crystal element 120. It becomes possible to do.

(First modification)
Hereinafter, the crystal device according to the first modification of the present embodiment will be described. Note that, in the quartz crystal device according to the first modification of the present embodiment, the same portions as those of the quartz crystal device described above are denoted by the same reference numerals, and description thereof will be omitted as appropriate. As shown in FIG. 3, the quartz crystal device according to the first modification of the present embodiment is different from the present embodiment in that the inner surface of the recess 131 is formed in an arc shape when viewed in cross section.

  The inner surface of the recess 131 is provided in an arc shape when viewed in cross section. Here, the dimension of one side when the sealing lid 130 is viewed in plan is 1.0 to 3.0 mm, the dimension in the thickness direction of the sealing lid 130 is 0.2 to 0.4 mm, The interval between the inner side surface and the outer side surface of the sealing frame portion 130b is 0.15 to 0.30 mm as an example, and the curvature radius of the recess 131 when viewed in cross section is 0.015 to 0.270 mm. It has become. Thus, even if the joining member 150 thermally expands by making the inner surface of the concave portion 131 arc, stress is evenly applied to the inner surface of the concave portion 131. Therefore, such a sealing lid 130 can relieve stress due to thermal expansion of the bonding member 150.

  The quartz crystal device according to the first modification of the present embodiment is provided so as to have an arc shape when the inner surface of the recess 131 of the sealing lid 130 is viewed in cross section. When heat is applied to the bonding member 150 and the bonding member 150 is thermally expanded, the inner surface of the recess 131 is arcuate when viewed in cross section, and therefore the bonding member 150 is evenly applied to the inner surface of the recess 131. Stress will be applied. Therefore, peeling of the sealing lid 130 from the substrate 110 can be further reduced.

(Second modification)
Hereinafter, the quartz crystal device according to the second modification of the present embodiment will be described. Of the quartz crystal device according to the second modification of the present embodiment, the same portions as 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 FIGS. 4 and 5, the quartz crystal device according to the second modification of the present embodiment is provided with a frame 210 b on the upper surface of the substrate 210 a and a plate-shaped sealing lid 230. This embodiment is different from the present embodiment in that a concave portion 231 is provided on the outer edge.

  As shown in FIGS. 1 and 2, the quartz crystal device according to the second modification of the present embodiment hermetically seals the package 210, the quartz crystal element 120 bonded to the upper surface of the package 210, and the quartz crystal element 120. The sealing lid body 230 to be included is included. The package 210 has an accommodation space K surrounded by the upper surface of the substrate 210a and the inner surface of the frame body 210b.

  The frame body 210b is disposed on the upper surface of the substrate 210a, and is for forming the accommodation space K on the upper surface of the substrate 210a. The frame 210b is made of a ceramic material such as alumina ceramics or glass-ceramics, and is formed integrally with the substrate 210a.

  The sealing lid 230 has a rectangular shape and is for hermetically sealing the housing space K in a vacuum state or the housing space K filled with nitrogen gas or the like. Specifically, the sealing lid 230 is placed on the frame 210b of the package 210 in a predetermined atmosphere. The upper surface of the frame body 210b and the bonding member 150 provided in the concave portion 231 of the sealing lid body 230 are melt bonded by applying heat.

  The recess 231 is provided so as to be cut out from the outer surface to the lower surface of the sealing lid 230. The recess 231 is continuously formed along the outer edge of the sealing lid 230. By doing so, the lower surface of the sealing lid 230 and the upper surface of the frame body 210b can be joined so as to surround the interior of the accommodation space K, so that the hermetic sealing performance in the accommodation space K is improved. Can do.

  The notch 232 is provided so as to penetrate vertically in at least one of the four corners of the sealing lid 230 in plan view. Further, the length of the notch 232 in the vertical direction is 0.2 to 0.4 mm. The notch 232 is provided so as to penetrate vertically in at least one of the four corners of the sealing lid 230 in plan view, and is provided so as to be connected to the recess 231. Therefore, when the sealing lid body 230 and the frame body 210b are joined by the joining member 150, the molten joining member 150 is joined so as to scoop up the outer surface of the notch 232. The bonding strength between 150 and the sealing lid 230 can be improved.

  In the crystal device according to the second modification of the present embodiment, a recess 231 is formed in the sealing lid 230 from the outer surface to the lower surface, and the lower surface of the sealing lid 230 is in contact with the upper surface of the frame 210b. In addition, the joining member 150 is provided from the inside of the recess 231 to the frame body 210b. By doing so, the gas generated from the bonding member 150 is blocked by the inner side surface of the concave portion 231 of the sealing lid 230, so that it is difficult to adhere to the crystal element 120. Therefore, the crystal resonator suppresses the gas from adhering to the crystal element 120, and the thickness shear vibration of the crystal element 120 is not hindered, so that the fluctuation of the oscillation frequency of the crystal element 120 can be reduced. .

  The notch 232 allows the gas generated from the molten joining member 150 to escape upward when the sealing lid 230 and the frame 210b are joined by the joining member 150. Further, the adhesion of the gas generated in the crystal element 120 can be further reduced. Therefore, since the thickness shear vibration of the crystal element 120 is not hindered, it is possible to further reduce the fluctuation of the oscillation frequency of the crystal element 120.

  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 second modification of the above embodiment, the case where the frame body 210b is integrally formed of a ceramic material in the same manner as the substrate 210a has been described. However, the frame body 210b 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 the frame is provided on the upper surface of the substrate has been described. However, after the crystal element is mounted on the substrate, the crystal element is hermetically sealed using the lid having the wall portion provided on the lower surface. It may be a structure that stops. In the above embodiment, the case where the crystal element for AT is used as the crystal element has been described. An element may be used.

  In addition, the crystal element 120 may be beveled so that the thickness of the outer periphery of the crystal element plate 121 is thin and the central part of the crystal element plate 121 is thicker than the outer periphery of the crystal element plate 121. . 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.

  In this embodiment, the case where the upper surface of the substrate 110 has no sealing conductor pattern has been described. However, the sealing conductor pattern may be provided on the upper surface of the substrate 110. The conductive pattern for sealing plays a role of improving the wettability of the bonding member 150 when bonded to the sealing lid 130 via the bonding member 150.

  In addition, when the conductive member is used as the bonding member 150, the sealing conductor pattern is formed by at least one external conductor by a via conductor (not shown) and a wiring pattern (not shown) formed in the substrate 110. Connected to terminal G. At least one external terminal G serves as a ground terminal by being connected to a mounting pad connected to a ground on an external mounting substrate. Therefore, the sealing lid 130 joined to the sealing conductor pattern is connected to the ground, and the shielding property in the accommodation space K by the sealing lid 130 is improved. The sealing conductor pattern is formed to have a thickness of, for example, 10 μm to 25 μm by sequentially applying nickel plating and gold plating on the surface of the conductor pattern made of tungsten, molybdenum, or the like, in a form surrounding the outer periphery of the upper surface of the substrate 110 in an annular shape Is formed.

110, 210a ... substrate 210b ... frame 210 ... package 111, 211 ... electrode pad 120 ... crystal element 121 ... crystal base plate 122 ... excitation electrode 123 ... Connection electrode 124 ... Lead electrode 130, 230 ... Sealing lid 131, 231 ... Recess 132, 232 ... Notch 140 ... Conductive adhesive 150 ... Joining member K ... Container space G ... External terminal

Claims (8)

A substrate,
A crystal element mounted on the substrate;
A sealing lid that is provided on the substrate and has a rectangular outer edge when viewed in plan, and covers the crystal element so as to seal it,
The sealing lid is formed with a recess cut out from the outer surface to the lower surface, the lower surface of the sealing lid contacts the upper surface of the substrate, and a bonding member extends from inside the recess to the substrate. A crystal device characterized by being provided. The crystal device according to claim 1,
The concave portion is formed continuously along the outer edge of the sealing lid. The crystal device according to claim 1,
The quartz crystal device, wherein an inner surface of the recess is formed in an arc shape when viewed in cross section. The crystal device according to claim 1,
A crystal device, wherein a cutout portion penetrating in a vertical direction is provided in at least one of the four corners of the sealing lid body in plan view. A substrate,
A frame provided on the substrate;
A crystal element mounted on the substrate and in the frame;
A sealing lid that is provided on the frame body and has an outer edge that is rectangular when viewed in plan, and covers the crystal element so as to seal,
The sealing lid has a recess formed by cutting from an outer surface to a lower surface, and the lower surface of the sealing lid contacts the upper surface of the frame and is joined from the inside of the recess to the frame. A quartz crystal device comprising a member. The crystal device according to claim 5,
The concave portion is formed continuously along the outer edge of the sealing lid. The crystal device according to claim 5,
The quartz crystal device, wherein an inner surface of the recess is formed in an arc shape when viewed in cross section. The crystal device according to claim 5,
A crystal device characterized in that a cutout portion penetrating in the vertical direction is provided in at least one of the four corners of the sealing lid in plan view.

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