JP2015070504A - Crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal device capable of inhibiting a joint member, which is provided between a sealing lid and a frame body, from adhering to a crystal element and thereby stably outputting the oscillatory frequency.SOLUTION: A crystal device includes: a substrate 110a; a frame body 110b provided along an outer peripheral edge on the substrate 110a; a crystal element 120 mounted on an area located on the substrate 110a and in the frame body 110b; a sealing lid 130 having a sealing base part 130a and a sealing frame part 130b provided on a lower surface of the sealing base part 130a; and a joint member 150 provided between an outer side surface of the frame body 110b and an inner side surface of the sealing frame part 130b.

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 package composed of a substrate and a frame, a crystal element mounted on an electrode pad provided on the upper surface of the substrate via a conductive adhesive, and a bonding member bonded to the upper surface of the frame A crystal resonator including a lid for hermetically sealing a crystal element has been proposed (see, for example, Patent Document 1 below). As the joining member, gold tin is used, and by applying heat to the joining member, the lid body and the upper surface of the frame body can be joined.

JP 2005-347851 A

  In the crystal device described above, since the lower surface of the lid and the upper surface of the frame of the package are bonded by the bonding member, when the bonding member melts, the bonding member enters the recess, and the bonding member is inserted into the crystal element. There is a risk of adhesion. Further, since the bonding member 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 an object of the present invention is to provide a crystal device capable of reducing the adhesion of a bonding member to a crystal element and stably outputting an oscillation frequency.

  A quartz crystal device according to an aspect of the present invention includes a substrate, a frame provided along an outer peripheral edge on the substrate, a crystal element mounted on the substrate in the frame, a sealing base, and a seal. A sealing lid having a sealing frame provided on the lower surface of the stop base, and a joining member provided between the outer surface of the frame and the inner surface of the sealing frame. It is characterized by that.

  A crystal device according to one aspect of the present invention includes a substrate, a frame provided along an outer peripheral edge on the substrate, a crystal element mounted on the substrate in the frame, a sealing base, A sealing lid having a sealing frame provided on the lower surface of the sealing base, and a bonding member provided between the outer surface of the frame and the inner surface of the sealing frame. I have. By doing in this way, when a joining member fuse | melts, it can reduce that the joined joining member fuse | melted to the quartz crystal element. In addition, such a quartz crystal device can stably output an oscillation frequency without inhibiting the thickness shear vibration of the quartz crystal element.

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 the perspective view which looked at the sealing lid which constitutes the crystal device in this embodiment from the lower surface. It is sectional drawing which shows the crystal device in the 1st modification of this embodiment. It is sectional drawing which shows the crystal device in the 2nd modification of this embodiment.

  As shown in FIGS. 1 and 2, the crystal device according to the present embodiment is bonded to the package 110, the crystal element 120 bonded to the upper surface of the package 110, and the outer surface of the frame 110 b of the package 110. The sealing lid body 130 is included. The package 110 has a first recess K1 surrounded by the upper surface of the substrate 110a and the inner surface of the frame 110b. Such a crystal 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 crystal element 120 bonded on the upper surface of the package 110. The substrate 110a is provided with an electrode pad 111 for bonding the crystal element 120 on the upper surface.

  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 an insulating layer or may be a laminate of a plurality of insulating layers. A wiring pattern and a via conductor for electrically connecting the electrode pad 111 provided on the upper surface and the external terminal 112 provided on the lower surface of the substrate 110a are provided on the surface or inside of the substrate 110a.

  The frame 110b is disposed on the upper surface of the substrate 110a, and is for forming the first recess K1 on the upper surface of 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.

  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 110a, and are provided adjacent to each other along one side of the substrate 110a. The electrode pad 111 is electrically connected to an external terminal 112 provided on the lower surface of the substrate 110a through a wiring pattern and a via conductor provided on the substrate 110a.

  The external terminal 112 is for mounting on a motherboard such as an electronic device. The external terminals are provided at the four corners of the lower surface of the substrate 110a. Two of the external terminals 112 are electrically connected to a pair of electrode pads 111 provided on the upper surface of the substrate 110a. The external terminals 112 that are electrically connected to the electrode pads 111 are provided so as to be located diagonally on the lower surface of the substrate 110a.

  Here, taking the case where the size of one side when the package 110 is viewed in plan is 0.8 to 3.0 mm and the vertical size of the package 110 is 0.7 to 1.5 mm, The size of one recess K1 will be described. The length of the long side of the first recess K1 is 0.7 to 2.5 mm, and the length of the short side is 0.5 to 2.0 mm. The vertical length of the first recess K1 is 0.2 to 0.5 mm.

  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 manufactured 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 terminals 112. 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 and an extraction electrode 123 are attached to the upper and lower surfaces of a 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 123 extends from the excitation electrode 122 toward the short side of the crystal base plate 121 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 110a, and the other end is a free end spaced from the upper surface of the substrate 110a. The crystal element 120 is fixed on the substrate 110a by the holding support structure.

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

  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 is manufactured by forming the excitation electrode 122 and the extraction electrode 123 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. Is done.

  A method for bonding the crystal element 120 to the substrate 110a 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 a pair of electrode pads 111 provided on the upper surface of the substrate 110a.

  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.

  As shown in FIGS. 2 and 3, the sealing lid 130 includes a rectangular sealing base portion 130a and a sealing frame portion 130b, and the lower surface of the sealing base portion 130a and the sealing frame portion 130b. A second concave portion K2 is formed with the inner side surface of the second concave portion K2. The sealing frame portion 130b is for forming the second recess K2 on the lower surface of the sealing base portion 130a. The sealing frame part 130b is provided along the outer edge of the lower surface of the sealing base part 130a. The second recess K2 is provided so as to accommodate the frame 110b of the package 110.

  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 first recess K1 in a vacuum state or the first recess K1 filled with nitrogen gas or the like. Specifically, the sealing lid 130 has a sealing base 130a placed on the upper surface of the frame 110b in a predetermined atmosphere, and the outer surface of the frame 110b and the sealing frame 130b of the sealing lid 130b. The joining member 150 provided between the inner surface and the inner surface is melt-joined by applying heat. Thus, when the sealing lid 130 is joined to the frame 110b, even if the molten joining member 150 overflows to the upper surface of the frame 110b, the joining member 150 is in the first recess K1. Intrusion can be reduced.

  Here, the magnitude | size of the 2nd recessed part K2 is demonstrated to the case where the dimension of one side when the sealing lid 130 is planarly viewed is 1.0-3.2 mm. The length of the long side of the second recess K2 is 1.4 to 3.0 mm, and the length of the short side is 0.8 to 2.3 mm. The vertical length of the second recess K2 is 0.2 to 0.5 mm. The size of the second recess K2 is provided to be larger than the outer dimension of the package 110, and the package 110 is joined so as to be accommodated in the second recess K2 of the sealing lid 130. become.

  As shown in FIG. 2, the joining member 150 is provided from the inner surface of the sealing frame portion 130b to the outer surface of the frame 110b. For example, in the case of glass, the joining member 150 is a glass that melts at 300 ° C. to 400 ° C., and is made of, for example, low-melting glass or lead oxide-based glass containing vanadium. Glass is pasty with a binder and a solvent added, and is melted and then solidified to adhere to other members. The joining member 150 is provided by, for example, applying glass frit paste to the inner side surface of the sealing frame part 130b or the outer side surface of the frame body 110b by screen printing and drying. The composition of the 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 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 between the outer surface of the frame 110b and the inner surface of the sealing frame portion 130b of the sealing lid 130 is 30 to 100 μm.

  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 crystal device according to the present embodiment includes a substrate 110a, a frame 110b provided along the outer peripheral edge on the substrate 110a, a crystal element 120 mounted on the substrate 110a and in the frame 110b, and a sealing device. Between the sealing lid 130 having a base portion 130a and a sealing frame portion 130b provided on the lower surface of the sealing base portion 130a, and between the outer side surface of the frame 110b and the inner side surface of the sealing frame portion 130b. And a joining member 150 provided in the housing. By doing so, the inner surface of the sealing frame portion 130 of the sealing lid 130 and the outer surface of the frame 110b are bonded together, so that the molten bonding member 150 overflows to the upper surface of the frame 110b. Moreover, it can reduce that the joining member 150 enters into the 1st recessed part K1. Therefore, it is possible to reduce the adhesion of the molten bonding member 150 to the crystal element 120. In addition, since the bonding member is prevented from adhering to the crystal element 120, the thickness-shear vibration of the crystal element 120 is not hindered, and the crystal device can stably output the oscillation frequency.

(First modification)
Hereinafter, the crystal device according to the first modification of the present embodiment will be described. Of the quartz crystal device according to the first modification of the present embodiment, the same parts as 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 first modification of the present embodiment, as shown in FIG. 4, the sealing lid 230 is arranged so that the upper surface of the frame 110b and the lower surface of the sealing base 230b are in contact with each other. It differs from the embodiment in that.

  As shown in FIG. 4, the sealing lid 230 is disposed such that the upper surface of the frame 110 b and the lower surface of the sealing base 230 b are in contact with each other, and the outer surface of the frame 110 b and the sealing lid 230. The sealing frame portion 230 b is joined to the inner side surface via the joining member 150. By doing in this way, the sealing lid 230 can be stably joined without causing a positional shift with the frame 110b of the package 110.

  The quartz crystal device according to the first modified example of the present embodiment is arranged so that the upper surface of the frame body 110b and the lower surface of the sealing base portion 230b of the sealing lid body 230 are in contact with each other. Positioning with the frame 110b of the package 110 can be facilitated, and stable bonding can be achieved. By doing in this way, the airtight sealing property in the 1st recessed part K1 of the package 110 can be maintained. Further, when the sealing lid 230 is joined to the frame 110b of the package 110, the upper surface of the frame 110b and the lower surface of the sealing base 230b of the sealing lid 230 even if the joining member 150 melts and scatters. , The contact of the joining member 150 into the first recess K1 can be further reduced. Therefore, the quartz crystal device can further reduce the adhesion of the bonding member 150 to the quartz crystal element 120 and stably output the oscillation frequency.

(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 parts 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 FIG. 5, the crystal device in the second modification of the present embodiment is electrically connected to one of the external terminals 212 provided on the lower surface of the substrate 210a. The conductor pad 213 is provided on the frame 210b, and is different from the embodiment in that the conductor pad 213, the sealing base 130a of the sealing lid 130, and the conductive bonding material 160 are joined.

  At least one conductor pad 213 is provided on the upper surface of the frame body 210b. The conductor pad 213 is electrically connected to one of the external terminals 212 provided on the lower surface of the substrate 210a via a via conductor and a wiring pattern provided inside the substrate 210a and the frame body 210b. The conductor pad 213 is mechanically and electrically bonded to the sealing base 130 a of the sealing lid 130 via the conductive bonding material 160. In addition, one of the external terminals 212 is connected to a mounting pad connected to a ground potential that is a reference potential on an external mounting substrate, whereby the sealing lid 130 is connected to the ground potential. It will be. By doing in this way, it can reduce that external electromagnetic noise is superimposed on the crystal element 120. Further, since the sealing lid 130 is connected to the ground potential, even if a metal plate or the like is close to the crystal device from above, stray capacitance is unlikely to occur between the adjacent metal plate and the crystal element 120. Thus, fluctuations in the oscillation frequency of the crystal element 120 can be reduced.

  For example, when the conductive bonding material 160 is gold tin, the thickness of the layer of the conductive bonding material 160 is 10 to 40 μm. For example, the component ratio is 70 to 80% for gold and 20 to 20 for tin. 30% may be used. Further, when the conductive bonding material 160 is, for example, silver solder, the thickness of the layer of the conductive bonding material 160 is 10 to 40 μm. For example, the component ratio is 70 to 80% for silver and copper is used. You may use a 20-30% thing.

  In the crystal device according to the second modification of the present embodiment, a conductor pad 213 electrically connected to one of the external terminals 213 provided on the lower surface of the substrate 210a is provided on the frame 210b, and the conductor pad is provided. 213, the sealing base 130 a of the sealing lid 130 and the conductive bonding material 160. By doing so, the sealing lid 130 is connected to the ground potential, and it is possible to reduce the external electromagnetic noise from being superimposed on the crystal element 120. Further, since the sealing lid 130 is connected to the ground potential, even if a metal plate or the like is close to the crystal device from above, stray capacitance is unlikely to occur between the adjacent metal plate and the crystal element 120. Thus, fluctuations in the oscillation frequency of the crystal element 120 can be reduced.

  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 first modification of the above-described embodiment, the case where the frame body 110b is integrally formed of a ceramic material similarly to the substrate 110a has been described. However, the frame body 110b may be made of metal. In this case, the frame 110b 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 crystal element for AT is used as the crystal element has been described. An element may be used. The tuning fork-type bent quartz crystal element includes a quartz piece, an excitation electrode provided on the surface of the quartz piece, a lead electrode, and a frequency adjusting metal film. The crystal piece includes a crystal base portion and a crystal vibration portion, and the crystal vibration portion includes a first crystal vibration portion and a second crystal vibration portion. The crystal base has an orthogonal coordinate system in which the electrical axis is the X axis, the mechanical axis is the Y axis, and the optical axis is the Z axis as the crystal axis direction, within a range of −5 ° to + 5 ° around the X axis. This is a flat plate having a substantially rectangular shape in a plan view in which the direction of the rotated Z ′ axis is the thickness direction. The first crystal vibrating part and the second crystal vibrating part are extended in parallel with the Y′-axis direction from one side of the crystal base part. Such a crystal piece has a tuning fork shape in which a crystal base and each crystal vibration part are integrated, and is manufactured by a photolithography technique and a chemical etching technique.

  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. By rotating the cylindrical body containing the abrasive and the quartz base plate 121 with the central axis of the cylindrical body as the rotation axis, the quartz base plate 121 is polished with the abrasive and beveled.

Moreover, in the said embodiment, although the joining member is melted and joined using a heating furnace, the method of carrying out airtight sealing by heating and melting a joining member by irradiating a laser etc. to a joining member may be sufficient. . As the type of this laser, for example, a carbon dioxide laser, a YAG laser, a YVO ₄ laser, a semiconductor laser, an excimer laser or the like is used.

110a, 211a ... substrate 110b, 210b ... frame 110, 210 ... package 111, 211 ... electrode pad 112, 212 ... external terminal 213 ... conductor pad 120 ... crystal element 121 ... crystal base plate 122 ... excitation electrode 123 ... extraction electrode 130, 230 ... sealing lid 130a, 230a ... sealing base 130b, 230b ... sealing frame 140 ... Conductive adhesive 150 ... Joint member 160 ... Conductive bonding material K1 ... First recess K2 ... Second recess

Claims (3)

A substrate,
A frame provided along an outer peripheral edge on the substrate;
A crystal element mounted on the substrate and in the frame;
A sealing lid having a sealing base and a sealing frame provided on the lower surface of the sealing base;
A crystal device, comprising: a joining member provided between an outer surface of the frame body and an inner surface of the sealing frame portion. The crystal device according to claim 1,
The crystal device according to claim 1, wherein the sealing lid is disposed so that an upper surface of the frame body and a lower surface of the sealing base are in contact with each other. The crystal device according to claim 1,
A conductive pad provided on the upper surface of the frame and electrically connected to one of the external terminals provided on the lower surface of the substrate;
The crystal device, wherein the conductor pad and the sealing base are joined.

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