JP6075082B2 - Quartz crystal resonator and its manufacturing method - Google Patents

Description

  The present invention relates to a mesa-type crystal unit in which crystal pieces having excitation electrodes formed on both front and back main surfaces are accommodated in a cantilevered state in a package, and more specifically, a crystal piece in a package. It relates to improving the characteristics depending on the support direction.

  The crystal resonator is one in which vibration is excited in the crystal by the piezoelectric inverse effect of the crystal when a voltage is applied to the excitation electrode, and is widely used in electronic components such as an oscillator as a reference source of frequency and time.

  The mesa-type crystal resonator includes an AT-cut crystal piece having a central thick portion, a peripheral thin portion on the outer peripheral side thereof, and excitation electrodes formed on both front and back main surfaces of the central thick portion. Including.

  In general, such a crystal resonator has excitation electrodes formed on both front and back surfaces of an AT-cut crystal piece. In the package, the excitation electrode is drawn out to either one of both ends in the X-axis direction of the crystal piece. The end is cantilevered (see, for example, Patent Document 1).

JP 2002-141765 A

  When such a conventional crystal unit is miniaturized and mass-produced, there are the following problems. For example, on the graph where the horizontal axis is the electrical constant of the crystal unit and the vertical axis is the frequency (the number of manufactured crystal units belonging to each electrical constant on the horizontal axis), If expressed by a frequency distribution showing the variation of the crystal, the crystal resonator may be mass-produced with two mountain-shaped frequency distributions.

  In this way, when the crystal constants are mass-produced with the electric constants varied, the crystal oscillators having an undesired electric constant are simultaneously produced in order to mass-produce the crystal oscillators having the desired electric constant. Will be mass-produced. In such mass production, the manufacturing yield of crystal resonators deteriorates.

  The present inventor found that the cause of mass production in this way is the characteristics of the crystal resonator depending on which end of the crystal piece is supported, that is, which end of the X-axis direction is the cantilever support side of the crystal piece. As a result, the present invention can be completed by repeating researches on a quartz crystal unit that cantilever-support a quartz crystal piece at both ends in the X-axis direction to provide desired characteristics. It came to.

  That is, an object of the present invention is to provide a crystal resonator that can be mass-produced with one desired frequency distribution of electrical constant frequency distribution and excellent in manufacturing yield, and a manufacturing method thereof.

(1) The crystal resonator according to the present invention includes at least an AT-cut crystal piece and excitation electrodes provided on both main surfaces of the crystal piece, and the crystal piece has at least a central portion in the X-axis direction in the thickness direction. A mesa-shaped part having a central thick part projecting thick and a peripheral thin part thinner than the central thick part on both sides in the X-axis direction of the central thick part, one end of the X-axis direction end portions of the crystal piece is a supported by a quartz oscillator cantilevered, the central thick portion is, unlike the X-axis direction on both sides of the edge shapes phase, the central thick The portion protrudes in a single step shape on one side in the thickness direction, and protrudes in a plurality of steps on the other side in the thickness direction so as to be thick .
The crystal resonator according to the present invention includes at least an AT-cut crystal piece and excitation electrodes provided on both front and back main surfaces of the crystal piece, and the crystal piece has at least a central portion in the X-axis direction in the thickness direction. The mesa-type having a thick central portion protruding and a thin peripheral portion thinner than the central thick portion on both sides in the X-axis direction of the central thick portion. A quartz crystal resonator in which one end portion of both ends of the X-axis direction is cantilevered, and the central thick portion has different end surface shapes on both sides in the X-axis direction. The center thick portion is provided on both the front and back main surfaces, and the center in the X-axis direction is deviated in the + X-axis direction or the -X-axis direction with respect to the center in the X-axis direction of the quartz crystal piece. A part of the + X-axis direction or the -X-axis direction Are formed to the edge the thin portion, the crystal blank, the + end of the other of the direction of the X-axis direction or the -X-axis direction is a fixed end, it is characterized.

  The present invention includes both a mesa type in which the central thick part protrudes on both sides in the thickness direction, a so-called bimesa type, a mesa type in which the central thick part protrudes in one direction in the thickness direction, and a so-called plano mesa type.

  In the present invention, the surface shape of the central thick part includes both a flat shape and a convex shape.

  In the present invention, it is preferable that the central thick portion protrudes in a single step shape on one side or both sides in the thickness direction and is thick.

  The central thick part preferably protrudes in a plurality of steps on one side or both sides in the thickness direction and is thick.

  It is preferable that the central thick part protrudes in a single step shape on one side in the thickness direction and protrudes in a plurality of steps on the other side in the thickness direction.

  The excitation electrode is provided on both the front and back main surfaces of the central thick portion, and the center in the X-axis direction is deviated in the + X-axis direction or the -X-axis direction with respect to the X-axis direction center of the crystal piece. Is preferred.

  Further, it is preferable that a part of the excitation electrode is formed up to the peripheral thin portion.

  Further, in the central thick part and the peripheral thin part, an angle formed by an end surface in the + X axis direction and a first reference plane (a plane parallel to the horizontal plane with the X axis direction as a horizontal plane) is a first angle α, It is preferable that an angle formed by an end surface in the −X-axis direction with a second reference surface parallel to the first reference surface is a second angle β and the relationship of α> β is satisfied.

  The first angle α is preferably 48 to 66 degrees, and the second angle β is preferably 20 to 42 degrees.

  Further, it is preferable that the crystal piece has a rectangular shape in a plan view having a long side in the X-axis direction.

(2) A method of manufacturing a crystal resonator according to the present invention includes a first step of preparing an AT-cut crystal piece, and forming a central thick part and a peripheral thin part at the periphery of the crystal piece. A second step of making the crystal piece a mesa type, a third step of chemically etching the crystal piece to form both end portions in the X-axis direction of the central thick portion on end faces having different shapes, and an excitation electrode Are formed on the front and back main surfaces of the central thick part, and a part thereof is formed up to the peripheral thin part in either the + X-axis direction or the -X-axis direction of the crystal piece. 4 steps, and a fifth step of joining the end of either the + X axis direction or the −X axis direction of the crystal piece as a fixed end. In the fourth step, the excitation electrode is The X-axis direction center is + X-axis direction with respect to the X-axis direction center of the crystal piece. It is formed so as to shift in the -X-axis direction, and wherein the.

  According to the present invention, since the end face shapes on both sides in the X-axis direction are different in the central thick part of the crystal piece, the end that can provide the desired characteristics of the crystal piece among the both ends based on the different shapes. Can be cantilevered on the side.

  As a result, in the present invention, the crystal resonators can be mass-produced so that the frequency distribution of the electrical characteristics is distributed in one mountain shape. Accordingly, the present invention can provide a crystal resonator that can be mass-produced with a high manufacturing yield.

  More specifically, according to the present invention, for example, there is a specification requirement for manufacturing a crystal resonator having a large electrical constant such as a C1 value (equivalent series capacitance value, the same applies hereinafter), or an electrical constant such as a C1 value. According to the specification requirement to manufacture a small crystal unit, it is easy to determine which end of a crystal piece should be cantilevered as a fixed end by identifying the difference in the chamfered shape. The manufacturing yield of the vibrator can be greatly improved.

FIG. 1 is a plan view of a crystal resonator according to a first embodiment of the present invention. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a plan view of a crystal resonator according to a second embodiment of the present invention. 4 is a cross-sectional view taken along line BB in FIG. FIG. 5 is a sectional view of a crystal resonator according to a third embodiment of the present invention. FIG. 6 is a sectional view of a crystal resonator according to a fourth embodiment of the present invention. FIG. 7 is a cross-sectional view of a crystal resonator according to a fifth embodiment of the present invention. FIG. 8 is a sectional view of a crystal resonator according to a sixth embodiment of the present invention. FIG. 9 is a sectional view of a crystal resonator according to a seventh embodiment of the present invention. FIG. 10 is a cross-sectional view of a crystal resonator according to an eighth embodiment of the present invention. FIG. 11 is a sectional view of a crystal piece of a crystal resonator according to a ninth embodiment of the present invention. FIG. 12 is a diagram showing a step of preparing a crystal piece in the method for manufacturing a crystal resonator according to the present invention. 13 is a cross-sectional view taken along the line CC of the crystal piece of FIG. FIG. 14 is a diagram showing a step of depositing a gold film on the entire peripheral surface of the crystal piece. FIG. 15 is a diagram showing a step of forming a photosensitive agent resist film on the gold film surface. FIG. 16 is a diagram showing a development process after exposure by selectively exposing the surface of the photosensitive resist film through an exposure mask. FIG. 17 is a diagram showing a process of removing the photosensitive resist film and the gold film on the region which becomes the peripheral thin wall portion, in which the photosensitive resist film on the region which becomes the central thick portion remains. FIG. 18 is a diagram illustrating a chemical etching process. FIG. 19 is a diagram showing a step of removing the gold film and the photosensitive resist film after chemical etching. FIG. 20 is a diagram illustrating a process of forming excitation electrodes on a crystal piece. FIG. 21 is a plan view of a crystal piece having an orientation flat.

  Hereinafter, a crystal resonator and a method for manufacturing the same according to an embodiment of the present invention will be described with reference to the accompanying drawings.

(Crystal oscillator)
With reference to FIGS. 1 and 2, the crystal resonator according to the first embodiment will be described.

  FIG. 1 is a plan view of the crystal resonator according to the first embodiment, and FIG. 2 is a cross-sectional view taken along line AA of FIG. As an example of the quartz crystal device, the quartz resonator 1 includes a quartz piece 2 that is AT-cut in a rectangular shape in plan view, and excitation electrodes 3a and 3b that are formed in a substantially rectangular shape in plan view on the front and back surfaces of the quartz piece 2. including.

  In the crystal piece 2, the X-axis direction is the long side direction of the crystal vibrating piece 2, the Z-axis direction is the short-side direction, and the Y-axis direction is the thickness direction. The X axis, the Z axis, and the Y axis are crystal axes of the AT cut crystal. Since the AT cut is well known, its details are omitted.

  The crystal piece 2 has a central thick portion 2a having a central portion protruding in the X-axis direction on both sides in the thickness direction and having a flat and thick surface, both sides in the X-axis direction of the central thick portion 2a, and A peripheral thin-walled portion 2b that protrudes in the ± X-axis direction from the center in the thickness direction and is thinner than the central thick-walled portion 2a. . The thicknesses of the central thick part 2a and the peripheral thin part 2b are shown for convenience of illustration, and therefore the thickness ratios are not limited to those shown in the drawings. Moreover, although the center thick part 2a shows equally the protrusion ratio which protrudes in thickness both directions with respect to the peripheral thin part 2b, the protrusion ratio is not limited equally.

  The central thick portion 2a has an end surface 2a1 chamfered at its + X-axis direction end and an end surface 2a2 chamfered at its −X-axis direction end. Although the illustrated chamfered shape is linear, it may be curvilinear. The chamfered shapes of these end faces 2a1 and 2a2 are different from each other to be discernable.

  Excitation electrodes 3a and 3b are formed uniformly on both the front and back main surfaces of the central thick portion 2a. The electrode thickness is exaggerated for convenience of illustration. The ends in the −X-axis direction of the excitation electrodes 3a and 3b are formed up to the peripheral thin portion 2b. The excitation electrodes 3a and 3b are formed such that the X-axis direction center C2 is shifted from the X-axis direction center C1 of the crystal piece 2 by a predetermined distance in the −X-axis direction. The predetermined distance is not particularly limited.

  The excitation electrodes 3a and 3b are drawn out by the extraction electrodes 4a and 4b to the end of the crystal piece 2 in the + X-axis direction.

  The crystal piece 2 is cantilevered at the end in the + X-axis direction by joining the support members 5a and 5b on the inner bottom surface of the package (not shown) with the joining materials 6a and 6b. In the crystal piece 2 in the cantilever support state, the end in the + X axis direction is a fixed end, and the end in the −X axis direction is a free end.

  The end surfaces 2a1 and 2a2 of the central thick portion 2a have an angle between the first reference surface S1 on the + X-axis direction side (a surface parallel to the horizontal plane with the X-axis direction as a horizontal plane) and the end surface 2a1, α and −X-axis directions. If the angle between the second reference surface S2 on the side (the surface parallel to the horizontal plane with the X-axis direction as the horizontal plane) and the end surface 2a2 is β, the relationship α> β is satisfied. Due to this relationship, as described above, the shapes of the end faces 2a1, 2a2 are different. The angle α is preferably 48 to 66 degrees, and the angle β is preferably 20 to 42 degrees. The relationship and numerical range of these angles α and β are the same in the following embodiments. The angles α and β are defined not only at the central thick portion 2a but also at the ridge portion of the peripheral thin portion 2b. The definition of the angles α and β is the same in the following embodiments.

  Depending on the magnitude relationship between the angles α and β of the end surfaces 2a1 and 2a2 of the central thick part 2a, it is identified which of the X-axis direction ends of the crystal piece 2 is in the + X-axis direction or the −X-axis direction. be able to.

  According to the crystal resonator 1, the shape of the end faces 2a1 and 2a2 of the central thick part 2a identifies which of the both ends of the crystal piece 2 is in the + X axis direction or the −X axis direction. Thus, the crystal piece 2 can be accommodated in the package with the end portion in the + X-axis direction being cantilevered as described above.

  Since the crystal unit 1 has the above-described structure, the crystal piece 2 can be manufactured by always supporting the crystal piece 2 with its end in the + X-axis direction being cantilevered as described above. Mass production is possible so that the frequency distribution of the predetermined electrical characteristics corresponding to the cantilever support at the end becomes one mountain. As a result, the crystal resonator 1 having the predetermined electrical constant can be mass-produced with a high manufacturing yield.

  A crystal resonator according to a second embodiment of the present invention will be described with reference to FIGS. 3 is a plan view of the crystal resonator, and FIG. 4 is a cross-sectional view taken along the line BB of FIG. 3 and 4, the same reference numerals are given to the portions corresponding to those in FIGS. 1 and 2.

  The crystal resonator 7 includes a crystal piece 2 and excitation electrodes 3a and 3b formed on the front and back main surfaces of the crystal piece 2 in a substantially rectangular shape in plan view.

  The crystal piece 2 has a central thick portion 2a whose center portion in the X-axis protrudes in a single step shape on both sides in the thickness direction and whose surface is flat and thick, and on both sides in the X-axis direction of the central thick portion 2a. And a thin peripheral portion 2b that protrudes from the central position in the thickness direction in the ± X-axis direction and is thinner than the central thick portion, and has a bimesa shape with the center being thicker than the peripheral portion. . The thicknesses of the central thick part 2a and the peripheral thin part 2b are shown for convenience of illustration, and therefore the thickness ratios are not limited to those shown in the drawings. Moreover, although the center thick part 2a shows equally the protrusion ratio which protrudes in thickness both directions with respect to the peripheral thin part 2b, the protrusion ratio is not limited equally.

  The central thick portion 2a has an end surface 2a1 chamfered at its + X-axis direction end portion and an end surface 2a2 chamfered at its −X-axis direction end portion. Although the illustrated chamfered shape is linear, it may be curvilinear. The chamfered shapes of these end faces 2a1 and 2a2 are different from each other to be discernable.

  Excitation electrodes 3a and 3b are formed on both main surfaces of the central thick part 2a. The ends in the + X-axis direction of the excitation electrodes 3a and 3b are formed up to the peripheral thin portion 2b. The excitation electrodes 3a and 3b are formed such that the X-axis direction center C2 is shifted from the X-axis direction center C1 of the crystal piece 2 by a predetermined distance in the + X-axis direction. The predetermined distance is not particularly limited. The excitation electrodes 3a and 3b are drawn out by the extraction electrodes 4a and 4b to the end of the crystal piece 2 in the −X-axis direction.

  The crystal piece 2 is cantilevered at the end in the −X-axis direction by joining the supporting members 5a and 5b on the inner bottom surface of the package (not shown) with the joining materials 6a and 6b. In the crystal piece 2 in the cantilever support state, an end in the −X axis direction is a fixed end, and an end in the + X axis direction is a free end.

  For the end surfaces 2a1 and 2a2 of the central thick portion 2a, the angle between the reference surface S1 and the end surface 2a1 on the + X axis direction side is α, and the angle between the reference surface S2 and the end surface 2a2 on the −X axis direction side is β. , Α> β is satisfied.

  The shape of the end surface 2a1 and the shape of the end surface 2a2 in the + X-axis direction differ depending on the magnitude relationship between the angles α and β of the end surfaces 2a1 and 2a2 of the central thick portion 2a. Can be identified as being in the + X-axis direction or the −X-axis direction.

  The crystal piece 2 is stored in a crystal piece storage portion of a package (not shown), and the end of the crystal piece 2 in the −X-axis direction is bonded to the support members 5a and 5b in the package by the bonding materials 6a and 6b. And cantilevered. The support member 5b and the bonding material 6b are illustrated because they appear on one side in the Z-axis direction, but the support member 5a and the bonding material 6a are not illustrated because they appear on the other side in the Z-axis direction. The same applies to the following embodiments.

  According to the crystal resonator 7, the crystal piece 2 can be identified from the shape of the end faces 2a1 and 2a2 of the crystal piece 2 by identifying which one of the both ends is in the + X-axis direction or the −X-axis direction. Can be stored in a package with the end portion in the −X-axis direction being cantilevered. Thereby, the crystal unit 7 can be mass-produced so that the frequency distribution of the predetermined electrical characteristics corresponding to the cantilever support at the end portion in the −X-axis direction becomes one peak, and as a result, the predetermined The quartz crystal resonator 7 having the electrical constant can be mass-produced with a high manufacturing yield.

  In the crystal resonators 1 and 6 of FIGS. 1 to 4, the peak of the frequency distribution of the C1 value is shifted. For example, the peak of the frequency distribution of the crystal resonator 1 is the first peak, and the frequency of the crystal resonator 6 is Assuming that the peak of the distribution is the second peak, in the experiment by the present inventor, the first peak of the frequency distribution of the crystal unit 1 has a large C1 value distribution and the second peak of the frequency distribution of the crystal unit 6. The mountains were distributed with a small overall C1 value. Therefore, for the specification requirement to manufacture a crystal resonator having a single C1 value frequency distribution and one large C1 value, the shapes of the end faces 2a1, 2a2 at both ends of the crystal piece 2 are identified, As shown in FIGS. 1 and 2, the crystal unit 1 can be manufactured by supporting the crystal piece 2 in a cantilever manner with the + X-axis direction end portion as a fixed end, and the C1 value frequency distribution is a single mountain shape. In addition, in response to a specification request to manufacture a crystal resonator having a small C1 value as a whole, the shape of the end faces 2a1, 2a2 at both ends of the crystal piece 2 is identified, and as shown in FIGS. The quartz resonator 7 can be manufactured by cantilevering the end portion of −2 in the −X-axis direction as a fixed end. As a result, the quartz crystal of the embodiment is compared with a conventional crystal resonator in which a C1 value frequency distribution is mass-produced in two mountain shapes and a crystal resonator having a large C1 value or a crystal resonator having a small C1 value is manufactured. In the vibrator, the manufacturing yield (production efficiency) can be greatly improved.

  In each of the following embodiments, similarly, the shape of the end faces 2a1 and 2a2 of the crystal piece 2 is identified, and a crystal resonator in which the peak of the C1 value frequency distribution is on the side with the larger C1 value is manufactured. Depending on whether the crystal resonator on the side with a smaller C1 value is to be manufactured, it is possible to determine which one of both ends of the crystal piece 2 is cantilevered and to manufacture the crystal resonator with a high manufacturing yield.

  A crystal resonator according to a third embodiment will be described with reference to FIG.

  The crystal resonator 8 includes an AT-cut crystal piece 2 having a rectangular shape in plan view, and excitation electrodes 3 a and 3 b formed in a substantially rectangular shape in plan view on the front and back surfaces of the crystal piece 2. In FIG. 5, the plan view of the crystal unit 8 is omitted. The same applies to the following embodiments.

  The crystal piece 2 has one main surface (lower surface side in the figure) as a flat surface, and the center of the other main surface (upper surface side in the figure) is formed in a single step on the one side in the thickness direction (Y-axis direction). The plano-mesa type has a central thick part 2a that protrudes and has a flat surface shape, and a peripheral thin part 2b that is thinner than the central thick part 2a on both sides in the X-axis direction of the central thick part 2a.

  The central thick portion 2a has an end surface 2a1 chamfered at its + X-axis direction end portion and an end surface 2a2 chamfered at its −X-axis direction end portion. The shapes of these end faces 2a1 and 2a2 are different to the extent that they can be identified. Excitation electrodes 3a and 3b are formed on the upper and lower surfaces of the central thick portion 2a. The ends in the −X-axis direction of the excitation electrodes 3a and 3b are formed up to the peripheral thin portion 2b. The excitation electrodes 3a and 3b are formed such that the X-axis direction center C2 is shifted from the X-axis direction center C1 of the crystal piece 2 by a predetermined distance in the −X-axis direction. The excitation electrodes 3a and 3b are drawn out to the end of the crystal piece 2 in the + X-axis direction by extraction electrodes 4a and 4b (the extraction electrode 4a is not shown). The extraction electrode 4b is illustrated because it appears on one side in the Z-axis direction, but the extraction electrode 4a is not illustrated because it appears on the other side in the Z-axis direction. The same applies to the following embodiments.

  The crystal piece 2 is cantilevered at the end in the + X-axis direction by joining the support members 5a and 5b on the inner bottom surface of the package (not shown) with the joining materials 6a and 6b. The support member 5b and the bonding material 6b are illustrated because they appear in one side in the Z-axis direction (through direction in the drawing), but the support member 5a and the bonding material 6a are not illustrated because they appear in the other side in the Z-axis direction. The crystal piece 2 has an end in the −X axis direction as a free end and an end in the + X axis direction as a fixed end.

  The end surfaces 2a1 and 2a2 have α> β, where α is the angle between the reference surface S1 on the + X-axis direction side and the end surface 2a1, and β is the angle between the reference surface S2 on the −X-axis direction side and the end surface 2a2. Satisfy the relationship.

  Depending on the magnitude relationship between the angles α and β of the end surfaces 2a1 and 2a2 of the central thick part 2a, it is identified which of the X-axis direction ends of the crystal piece 2 is in the + X-axis direction or the −X-axis direction. be able to.

  The crystal piece 2 is housed in a crystal piece housing portion of a package (not shown), and the end of the crystal piece 2 in the + X-axis direction is joined to the support members 5a and 5b in the package by the joining materials 6a and 6b. Can be cantilevered.

  According to the crystal unit 8, the crystal piece 2 is identified based on the shape of the end surfaces 2a1 and 2a2 of the crystal piece 2 by identifying which of the both ends is in the + X-axis direction or the −X-axis direction. 2 can be stored in a package with the + X-axis direction end being cantilevered. As a result, the crystal resonator 8 can be mass-produced so that the frequency distribution of the electrical characteristics becomes one peak, and can be provided as a crystal resonator with a high manufacturing yield.

  A crystal resonator according to a fourth embodiment of the present invention will be described with reference to FIG.

  The crystal resonator 9 includes a crystal piece 2 and excitation electrodes 3 a and 3 b formed on the front and back surfaces of the crystal piece 2 in a substantially rectangular shape in plan view.

  The crystal piece 2 has one main surface (lower surface side in the figure) as a flat surface, the center of the other main surface (upper surface side in the figure) projects in a single step shape on one side in the thickness direction, and the surface shape is flat. The center thick portion 2a is a planomesa type having both the central thick portion 2a and the peripheral thin portion 2b thinner on both sides in the X-axis direction than the central thick portion 2a.

  The central thick portion 2a has an end surface 2a1 chamfered at its + X-axis direction end portion and an end surface 2a2 chamfered at its −X-axis direction end portion. The shapes of these end faces 2a1 and 2a2 are different to the extent that they can be identified. Excitation electrodes 3a and 3b are formed on both main surfaces of the central thick part 2a. The ends in the + X-axis direction of the excitation electrodes 3a and 3b are formed up to the peripheral thin portion 2b. The excitation electrodes 3a and 3b are formed such that the X-axis direction center C2 is shifted from the X-axis direction center C1 of the crystal piece 2 by a predetermined distance in the + X-axis direction. The excitation electrodes 3a and 3b are drawn out by the extraction electrodes 4a and 4b to the end of the crystal piece 2 in the −X-axis direction. The crystal piece 2 is cantilevered at the end in the −X-axis direction by joining the supporting members 5a and 5b on the inner bottom surface of the package (not shown) with the joining materials 6a and 6b. The crystal piece 2 has an end in the −X axis direction as a fixed end and an end in the + X axis direction as a free end.

  The end surfaces 2a1 and 2a2 of the central thick part 2a have an angle between the reference surface S1 and the end surface 2a1 on the + X-axis direction side as α, an angle between the reference surface S2 on the −X-axis direction side and the end surface 2a2 as β, and Then, the relationship of α> β is satisfied.

  Identify which end of the crystal piece 2 in the X-axis direction is the + X-axis direction or the -X-axis direction by the magnitude relationship of the end-face angles α and β of the end faces 2a1 and 2a2 of the central thick part 2a can do.

  The crystal piece 2 is stored in a crystal piece storage portion of a package (not shown), and the end of the crystal piece 2 in the −X-axis direction is bonded to the support members 5a and 5b in the package by the bonding materials 6a and 6b. And cantilevered.

  According to the crystal unit 9, the crystal piece 2 is identified based on the shape of the end faces 2a1 and 2a2 of the crystal piece 2 by identifying which of the both ends is in the + X-axis direction or the −X-axis direction. 2 can be accommodated in a package with its end in the -X-axis direction being cantilevered. Thereby, the crystal unit 9 becomes. A crystal resonator that can be mass-produced so that the frequency distribution of electrical characteristics is one peak and has a high manufacturing yield can be provided.

  A crystal resonator according to a fifth embodiment will be described with reference to FIG.

  The crystal unit 10 includes an AT-cut crystal piece 2 having a rectangular shape in plan view, and excitation electrodes 3a and 3b formed on the front and back surfaces of the crystal piece 2 in a substantially rectangular shape in plan view.

  The crystal piece 2 has a central thick portion 2a that protrudes in a single step shape on both sides in the thickness direction and has a thick convex surface (convex lens shape), and a central thickness on both sides in the X-axis direction of the central thick portion 2a. It is a bimesa type having a thin peripheral portion 2b that is thinner than the meat portion 2a and has a curved surface.

  The central thick portion 2a has an end surface 2a1 at its + X-axis direction end and an end surface 2a2 at its −X-axis direction end. The shapes of these end faces 2a1, 2a2 are different. Excitation electrodes 3a and 3b are formed on both main surfaces of the central thick part 2a. The ends in the −X-axis direction of the excitation electrodes 3a and 3b are formed up to the peripheral thin portion 2b. The excitation electrodes 3 a and 3 b are formed such that the X-axis direction center C <b> 2 is shifted in the −X-axis direction with respect to the X-axis direction center C <b> 1 of the crystal piece 2. The excitation electrodes 3a and 3b are drawn out to the end of the crystal piece 2 in the + X-axis direction by the extraction electrodes 4a and 4b (the extraction electrode 4b is not shown).

  The crystal piece 2 is cantilevered at the end in the + X-axis direction by joining the support members 5a and 5b on the inner bottom surface of the package (not shown) with the joining materials 6a and 6b. The crystal piece 2 has an end in the + X-axis direction as a fixed end and an end in the −X-axis direction as a free end.

  The end surfaces 2a1 and 2a2 have α> β, where α is the angle between the reference surface S1 on the + X-axis direction side and the end surface 2a1, and β is the angle between the reference surface S2 on the −X-axis direction side and the end surface 2a2. Satisfy the relationship.

  Identify which end of the crystal piece 2 in the X-axis direction is the + X-axis direction or the -X-axis direction by the magnitude relationship of the end-face angles α and β of the end faces 2a1 and 2a2 of the central thick part 2a can do.

  The crystal piece 2 is housed in a crystal piece housing portion of a package (not shown), and the end of the crystal piece 2 in the + X-axis direction is joined to the support members 5a and 5b in the package by the joining materials 6a and 6b. Can be cantilevered.

  According to the crystal resonator 10, the shape of the end faces 2a1 and 2a2 of the crystal piece 2 is observed, and by identifying which one of the both ends is in the + X-axis direction or the −X-axis direction, The piece 2 can be accommodated by cantilevering the + X-axis direction end in the package. As a result, the crystal resonator 10 can be mass-produced so that the frequency distribution of the electrical characteristics becomes one peak, and can be provided as a crystal resonator with a high manufacturing yield.

  A crystal unit according to a sixth embodiment of the present invention will be described with reference to FIG.

  The crystal unit 11 includes a crystal piece 2 and excitation electrodes 3 a and 3 b formed on the front and back surfaces of the crystal piece 2 in a substantially rectangular shape in plan view.

  The crystal piece 2 includes a central thick portion 2a that protrudes in a single step shape on both sides in the thickness direction and has a thick surface having a convex shape, and a central thick portion 2a on both sides in the X-axis direction of the central thick portion 2a. Also, it is a bi-mesa type having a thin peripheral portion 2b with both main surfaces curved.

  The central thick portion 2a has an end surface 2a1 at its + X-axis direction end and an end surface 2a2 at its −X-axis direction end. The shapes of these end faces 2a1, 2a2 are different. Excitation electrodes 3a and 3b are formed on both main surfaces of the central thick part 2a. The ends in the + X-axis direction of the excitation electrodes 3a and 3b are formed up to the peripheral thin portion 2b. The excitation electrodes 3a and 3b are formed such that the X-axis direction center C2 is shifted in the + X-axis direction with respect to the X-axis direction center C1 of the crystal piece 2. The excitation electrodes 3a and 3b are drawn out by the extraction electrodes 4a and 4b to the end of the crystal piece 2 in the −X-axis direction. The crystal piece 2 is cantilevered at the end in the −X-axis direction by joining the supporting members 5a and 5b on the inner bottom surface of the package (not shown) with the joining materials 6a and 6b. The crystal piece 2 has an end in the + X-axis direction as a free end and an end in the −X-axis direction as a fixed end.

  The end surfaces 2a1 and 2a2 of the central thick part 2a have an angle between the reference surface S1 and the end surface 2a1 on the + X-axis direction side as α, an angle between the reference surface S2 on the −X-axis direction side and the end surface 2a2 as β, and Then, the relationship of α> β is satisfied.

  Identify which end of the crystal piece 2 in the X-axis direction is the + X-axis direction or the -X-axis direction by the magnitude relationship of the end-face angles α and β of the end faces 2a1 and 2a2 of the central thick part 2a can do.

  The crystal piece 2 is stored in a crystal piece storage portion of a package (not shown), and the end of the crystal piece 2 in the −X-axis direction is bonded to the support members 5a and 5b in the package by the bonding materials 6a and 6b. And cantilevered.

  According to the crystal unit 11, the shape of the end faces 2a1 and 2a2 of the crystal piece 2 is seen, and by identifying which one of the both ends is in the + X-axis direction or the −X-axis direction, The piece 2 can be accommodated by cantilevering the end in the −X-axis direction in the package. As a result, the crystal unit 11 can be mass-produced so that the frequency distribution of the electrical characteristics becomes one peak, and can be provided as a crystal unit with a high manufacturing yield.

  A crystal resonator according to a seventh embodiment will be described with reference to FIG.

  The crystal unit 12 includes an AT-cut crystal piece 2 having a rectangular shape in plan view, and excitation electrodes 3a and 3b formed on the front and back surfaces of the crystal piece 2 in a substantially rectangular shape in plan view. The crystal piece 2 has one main surface (lower surface side in the figure) as a flat surface, and the center of the other main surface (upper surface side in the figure) is formed in a single step on the one side in the thickness direction (Y-axis direction). A central thick part 2a having a convex surface shape with a convex shape, and a peripheral peripheral thin part 2b whose both sides in the X-axis direction of the central thick part 2a are thinner than the central thick part 2a and have a curved shape. It has a planomesa type.

  The central thick portion 2a has an end surface 2a1 that is chamfered in a curved shape at its + X-axis direction end portion, and an end surface 2a2 that is chamfered in a curved shape at its −X-axis direction end portion. The shapes of these end faces 2a1 and 2a2 are different to the extent that they can be identified. Excitation electrodes 3a and 3b are formed on the upper and lower surfaces of the central thick portion 2a. The ends in the −X-axis direction of the excitation electrodes 3a and 3b are formed up to the peripheral thin portion 2b. The excitation electrodes 3 a and 3 b are formed such that the X-axis direction center C <b> 2 is shifted in the −X-axis direction with respect to the X-axis direction center C <b> 1 of the crystal piece 2. The excitation electrodes 3a and 3b are drawn out by the extraction electrodes 4a and 4b to the end of the crystal piece 2 in the + X-axis direction.

  The crystal piece 2 is cantilevered at the end in the + X-axis direction by joining the support members 5a and 5b on the inner bottom surface of the package (not shown) with the joining materials 6a and 6b. The crystal piece 2 has an end in the −X axis direction as a free end and an end in the + X axis direction as a fixed end.

  The end surfaces 2a1 and 2a2 have α> β, where α is the angle between the reference surface S1 on the + X-axis direction side and the end surface 2a1, and β is the angle between the reference surface S2 on the −X-axis direction side and the end surface 2a2. Satisfy the relationship.

  Identify which end of the crystal piece 2 in the X-axis direction is the + X-axis direction or the -X-axis direction by the magnitude relationship of the end-face angles α and β of the end faces 2a1 and 2a2 of the central thick part 2a can do.

  The crystal piece 2 is housed in a crystal piece housing portion of a package (not shown), and the end of the crystal piece 2 in the + X-axis direction is joined to the support members 5a and 5b in the package by the joining materials 6a and 6b. Can be cantilevered.

  According to the crystal unit 12, the shape of the end faces 2a1 and 2a2 of the crystal piece 2 is seen, and by identifying which one of the both ends is in the + X axis direction or the −X axis direction, The piece 2 can be accommodated by cantilevering the + X-axis direction end in the package. As a result, the crystal unit 12 can be mass-produced so that the frequency distribution of the electrical characteristics becomes one peak, and can be provided as a crystal unit with a high manufacturing yield.

  A crystal resonator according to an eighth embodiment of the present invention will be described with reference to FIG.

  The crystal resonator 13 includes a crystal piece 2 and excitation electrodes 3 a and 3 b formed on the front and back surfaces of the crystal piece 2 in a substantially rectangular shape in plan view.

  The crystal piece 2 has a flat surface on one main surface (the lower surface side in the drawing), the center of the other main surface (the upper surface side in the drawing) protrudes in a single step on one side in the thickness direction, and the surface shape is convex. It is a planomesa type having a thick central portion 2a having a shape, and a thin peripheral portion 2b having a curved surface that is thinner than the central thick portion 2a on both sides in the X-axis direction of the central thick portion 2a. Yes.

  The central thick portion 2a has an end surface 2a1 that is chamfered in a curved shape at its + X-axis direction end portion, and an end surface 2a2 that is chamfered in a curved shape at its −X-axis direction end portion. The shapes of these end faces 2a1 and 2a2 are different to the extent that they can be identified.

  Excitation electrodes 3a and 3b are formed on both main surfaces of the central thick part 2a. The ends in the + X-axis direction of the excitation electrodes 3a and 3b are formed up to the peripheral thin portion 2b. The excitation electrodes 3a and 3b are formed such that the X-axis direction center C2 is shifted in the + X-axis direction with respect to the X-axis direction center C1 of the crystal piece 2. The excitation electrodes 3a and 3b are drawn out by the extraction electrodes 4a and 4b to the end of the crystal piece 2 in the −X-axis direction. The crystal piece 2 is cantilevered at the end in the −X-axis direction by joining the supporting members 5a and 5b on the inner bottom surface of the package (not shown) with the joining materials 6a and 6b. The crystal piece 2 has an end in the + X-axis direction as a free end and an end in the −X-axis direction as a fixed end.

  The end surfaces 2a1 and 2a2 of the central thick part 2a have an angle between the reference surface S1 and the end surface 2a1 on the + X-axis direction side as α, an angle between the reference surface S2 on the −X-axis direction side and the end surface 2a2 as β, and Then, the relationship of α> β is satisfied. The reference planes S1 and S2 are planes parallel to the horizontal plane when the X-axis direction is a horizontal plane.

  Identify which end of the crystal piece 2 in the X-axis direction is the + X-axis direction or the -X-axis direction by the magnitude relationship of the end-face angles α and β of the end faces 2a1 and 2a2 of the central thick part 2a can do.

  The crystal piece 2 is stored in a crystal piece storage portion of a package (not shown), and the end of the crystal piece 2 in the −X-axis direction is bonded to the support members 5a and 5b in the package by the bonding materials 6a and 6b. And cantilevered.

  According to the crystal resonator 13, based on the difference in shape of the end faces 2 a 1 and 2 a 2 of the crystal piece 2, it is possible to identify which of the both ends is in the + X axis direction or the −X axis direction. The crystal piece 2 can be accommodated in the package with the end portion in the −X-axis direction being cantilevered. As a result, the crystal resonator 13 can be mass-produced so that the frequency distribution of the electrical characteristics becomes one peak, and can be provided as a crystal resonator with a high manufacturing yield.

  FIG. 11 illustrates a crystal resonator according to a ninth embodiment of the present invention. In FIG. 11, the excitation electrodes 3a and 3b, the bonding materials 5a and 5b, and the support members 6a and 6b are not shown.

  The crystal resonator 14 includes a crystal piece 2. The crystal piece 2 has one main surface (the lower surface side in the drawing) is a flat surface, and the center of the other main surface (the upper surface side in the drawing) protrudes in one step in the thickness direction in a stepped shape. A thick thick central portion 2a and a planomesa type having both the central thick portion 2a in the X-axis direction and a thin peripheral portion 2b having a curved shape and thinner than the central thick portion 2a. The excitation electrode is not shown. In addition, in FIG. 11, although the center thick part 2a protrudes in two steps, you may make it protrude in multiple steps | paragraphs of three steps or more although not shown in figure. In FIG. 11, the central thick part 2a protrudes on one side in the thickness direction, but although not shown, it may be protruded in two or more steps on both sides in the thickness direction. Furthermore, in FIG. 11, the central thick part 2 a protrudes in two steps on one side in the thickness direction, although not shown, it is a single step on the one side in the thickness direction and two or more steps on the other side in the thickness direction. You may make it project.

  The central thick portion 2a has an end surface 2a1 that is chamfered in a curved shape at its + X-axis direction end portion, and an end surface 2a2 that is chamfered in a curved shape at its −X-axis direction end portion. The shapes of these end faces 2a1 and 2a2 are different to the extent that they can be identified. The end faces 2a1 and 2a2 have a plurality of steps. One end surface 2a1 has two end surfaces 2a11 and 2a12. The other end face 2a2 is two end faces 2a21, 2a22. Excitation electrodes are formed on both main surfaces of the central thick portion 2a as shown in FIGS.

  The angle between the end surface 2a11 on the + X-axis direction side and the reference surface S11 is α1, the angle between the end surface 2a12 and the reference surface S12 is α2, and the angle between the end surface 2a21 on the −X-axis direction side and the reference surface S21. When β1 is β2 and the angle between the end surface 2a22 and the reference surface S22 is β2, the relationship of α1> β1 and α2> β2 is satisfied.

  Based on the magnitude relationship of the angles, it is possible to identify which of the ends of the crystal piece 2 in the X-axis direction is the + X-axis direction or the −X-axis direction.

(Quartz crystal manufacturing method)
A method for manufacturing the crystal unit 8 shown in FIG. 5 will be described with reference to FIGS.

  First, as shown in FIG. 13, which is a plan view of FIG. 12 and a cross-sectional view taken along the line CC of FIG. 12, a crystal piece 2 that is AT-cut in a rectangular shape in plan view with a uniform thickness is prepared. The crystal piece 2 has a rectangular shape in plan view in which the X-axis direction is the long side and the Z-axis direction is the short side.

  Next, as shown in FIG. 14, a gold film 10 is uniformly deposited on the entire peripheral surface of the crystal piece 2 by a known deposition technique. Next, as shown in FIG. 15, a photosensitive resist film 11 is uniformly formed on the surface of the gold film 10. The thickness of the crystal piece 2 and the thickness of the gold film 10 and the photosensitive agent resist film 11 with respect to the crystal piece 2 are shown for convenience of illustration.

  Next, as shown in FIG. 16, the surface of the photosensitive resist film 11 is selectively exposed through an exposure mask (not shown). In this selection, the region to be the central thick portion 2a is shielded from light, and the region to be the peripheral thin portion 2b on both sides in the X-axis direction of the central thick portion 2a is exposed.

  When developed after this exposure, as shown in FIG. 17, the photosensitive resist film 11 on the region that becomes the central thick portion 2a remains, and the photosensitive resist film 11 and the gold film 10 on the region that becomes the peripheral thin portion 2b. Is removed.

  Next, chemical etching is performed as shown in FIG. 18, and then, as shown in FIG. 19, when the gold film 10 and the photosensitive resist film 11 are removed, the central thick part 2a and the central thick part 2a in the X-axis direction A planomesa type crystal piece 2 composed of the peripheral thin wall portions 2b on both sides is obtained. The chemical etching is performed by immersing the crystal piece 2 in an etching solution of ammonium acid fluoride. In this embodiment, the chemical etching is performed so as to be about 2 to 30% thinner than the thickness of the crystal piece before etching.

  As shown in FIG. 19, in this crystal piece 2, end faces 2a1 and 2a2 chamfered on both sides in the X-axis direction of the central thick part 2a are formed by chemical etching.

  By this chemical etching, the crystal piece 2 is flat at the lower surface side in the figure, and becomes a central thick part 2a in which the center of the upper surface side protrudes in the figure, and both sides of the central thick part 2a in the X-axis direction are thick at the center. It becomes a planomesa type having a thinner peripheral portion 2b that is thinner than the portion 2a.

  The central thick portion 2a is formed with an end surface 2a1 at the + X-axis direction end portion and an end surface 2a2 at the −X-axis direction end portion. As described in FIG. 5, the end surfaces 2a1 and 2a2 have an angle between the end surface 2a1 on the + X-axis direction side and the reference surface S1, α, an angle between the end surface 2a2 on the −X-axis direction side and the reference surface S2, and β. Then, the relationship of α> β is satisfied.

  Then, as shown in FIG. 20, excitation electrodes 3 a and 3 b are formed on the upper and lower surfaces of the central thick part 2 a of the crystal piece 2. The ends of the excitation electrodes 3a and 3b in the −X-axis direction are formed up to the peripheral thin portion 2b. The excitation electrodes 3a and 3b are formed such that the X-axis direction center C2 of the crystal piece 2 is shifted in the -X-axis direction with respect to the X-axis direction center C1. The excitation electrodes 3a and 3b are drawn out by the extraction electrodes 4a and 4b to the + X-axis direction end of the crystal piece 2. Next, the end of the crystal piece 2 in the + X-axis direction is cantilevered by joining the support members 5a and 5b with the joining materials 6a and 6b.

  Thereby, the crystal resonator shown in FIG. 5 can be obtained. In this manufacturing method, a planomesa type crystal resonator is manufactured, but a bimesa type can also be manufactured in the same manner.

  In the manufactured quartz resonator, either one of both ends of the crystal piece 2 in the X-axis direction is dependent on the magnitude relationship between the angles α and β sandwiched between the end surfaces 2a1 and 2a2 of the central thick part 2a and the reference surfaces S1 and S2. , + X-axis direction or −X-axis direction can be identified. The production of other crystal units is the same.

  When the crystal piece has a circular chip configuration in plan view, as shown in FIG. 21, if the crystal piece 2 is manufactured using the crystal piece 2 in which the orientation flat 21 is formed on a part of the outer periphery thereof, the orientation flat 21 Can be used to identify whether the X-axis direction end of the crystal piece 2 is in the + X-axis direction or the −X-axis direction. Note that the orientation flat is generally a straight line portion on the periphery of the circular tip, but is not limited to this, and includes a partially cutout or the like.

DESCRIPTION OF SYMBOLS 1 Crystal oscillator 2 Crystal piece 2a Center thick part 2a1 + X-axis direction end surface 2a2 -X-axis direction end surface 2b Peripheral thin part 3a, 3b Excitation electrode 4a, 4b Extraction electrode 5a, 5b Support member 6a, 6b Joining material

Claims (8)

The crystal piece includes at least an AT-cut crystal piece and excitation electrodes provided on both front and back main surfaces of the crystal piece, and the crystal piece has a central thick wall with at least a central portion in the X-axis direction protruding in the thickness direction. And a peripheral thin portion that is thinner than the central thick portion on both sides in the X-axis direction of the central thick portion, and is a mesa type, and one of both ends in the X-axis direction of the crystal piece A quartz crystal whose end is cantilevered,
The central thick portion is, unlike the X-axis direction on both sides of the edge shapes phases,
The center thick part protrudes in a single step shape on one side in the thickness direction and protrudes in a plurality of steps on the other side in the thickness direction so as to be thick . The crystal piece includes at least an AT-cut crystal piece and excitation electrodes provided on both front and back main surfaces of the crystal piece, and the crystal piece has a central thick wall with at least a central portion in the X-axis direction protruding in the thickness direction. And a peripheral thin portion that is thinner than the central thick portion on both sides in the X-axis direction of the central thick portion, and is a mesa type, and one of both ends in the X-axis direction of the crystal piece A quartz crystal whose end is cantilevered,
The central thick part has different end face shapes on both sides in the X-axis direction,
The excitation electrode is provided on both the front and back main surfaces of the central thick part, and its X-axis direction center is shifted in the + X-axis direction or the -X-axis direction with respect to the X-axis direction center of the crystal piece,
A part of the excitation electrode is formed up to the peripheral thin portion in either the + X-axis direction or the −X-axis direction,
The quartz crystal resonator is characterized in that an end of either the + X-axis direction or the -X-axis direction is a fixed end . The quartz resonator according to claim 2 , wherein the central thick portion protrudes in a single step shape on one side or both sides in the thickness direction and is thick. The quartz resonator according to claim 2 , wherein the central thick portion protrudes in a plurality of steps on one side or both sides in the thickness direction and is thick. A first angle α sandwiched between an end face in the + X axis direction and a first reference plane (a plane parallel to the horizontal plane with the X axis direction as a horizontal plane) and the −X axis direction in the central thick portion and the peripheral thin portion 5. The crystal resonator according to claim 1 , wherein a second angle β sandwiched between an end surface of the first reference surface and a second reference surface parallel to the first reference surface satisfies a relationship of α> β . The crystal unit according to claim 5, wherein the first angle α is 48 to 66 degrees, and the second angle β is 20 to 42 degrees . The crystal unit according to claim 1 , wherein the crystal piece has a rectangular shape in a plan view having a long side in the X-axis direction . A first step of preparing an AT-cut crystal piece;
Forming a central thick part and a peripheral thin part on the periphery of the crystal piece, and making the crystal piece a mesa shape;
A third step of chemically etching the quartz piece to form both end portions in the X-axis direction of the central thick portion on end surfaces having different shapes;
Excitation electrodes are formed on the front and back main surfaces of the central thick part, and part of the excitation electrode is formed up to the peripheral thin part in either the + X axis direction or the −X axis direction of the crystal piece. And a fourth step to
A fifth step of joining, as a fixed end, an end of the crystal piece in either the + X-axis direction or the −X-axis direction.
In the fourth step, the excitation electrode is formed such that the center in the X-axis direction is shifted in the + X-axis direction or the −X-axis direction with respect to the X-axis direction center of the crystal piece.
A method of manufacturing a crystal resonator.

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