JP2010010955A - Method for manufacturing piezoelectric vibrator, and piezoelectric vibrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a piezoelectric vibrator which ensures high oscillation precision, and to provide the piezoelectric vibrator manufactured by the method of manufacturing. <P>SOLUTION: The piezoelectric vibrator is manufactured so as to include steps of: etching a first piezoelectric substrate to form a through-hole; forming an etching mask constituting the shape of a convex lens on one surface of a second piezoelectric substrate; etching one surface of the second piezoelectric substrate on which the etching mask is formed to form a vibration part in the shape of the convex lens corresponding to the etching mask; joining a first substrate to the second piezoelectric substrate so that the vibration part is settled in a projection region of the through-hole to the second piezoelectric substrate; and segmenting a piezoelectric piece from the first piezoelectric substrate and the second piezoelectric substrate joined along the outer shape of a holding part for surrounding around the vibration part to hold the vibration part, wherein an etching amount for forming the vibration part is suppressed, and surface roughness of the vibration part is suppressed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a piezoelectric vibrator manufacturing method and a piezoelectric vibrator manufactured by the manufacturing method.

  An electronic component including a piezoelectric vibrator such as a quartz vibrator is used as an oscillation source of a reference frequency or a clock source of an electronic device. In recent years, with the advancement of optical communication technology and digital processing technology, the high density and high speed of information communication have been remarkably advanced, and for this reason, the resonance frequency of the crystal unit has been increased and the accuracy of oscillation has been increased. .

  Since the resonance frequency of the crystal resonator is inversely proportional to the thickness of the crystal piece constituting the crystal resonator, the thinning of the crystal piece is being promoted in order to increase the frequency. For example, a quartz resonator that emits a fundamental wave of 622 MHz has been announced at present, but the quartz piece of this quartz resonator has a thickness of only 2 μm. In addition, in order to increase the accuracy of oscillation, the outer shape of the crystal piece may be processed so that the surface (vibration surface) of the vibrating portion of the crystal piece is a curved surface having a convex lens shape. When such processing is performed, the vibration of the vibration part is stabilized and the occurrence of spurious is suppressed.

  In order to process the vibration surface of the crystal piece into a convex lens shape as described above, for example, a mask material is formed on a crystal wafer, the mask material is shaped into a convex lens shape, and then the crystal wafer is dried on the crystal wafer. In some cases, processing of a convex lens shape at the wafer level is performed, such as etching. In this case, the surface of the crystal wafer below the mask material is etched, the shape of the surface of the mask material is transferred to the surface of the crystal wafer, and then the crystal wafer is cut to manufacture a crystal resonator.

  However, according to this manufacturing method, the outer peripheral part of the vibration part formed in the convex lens shape is thinner than the vibration part. As described above, since the thinning of the crystal piece is progressing in order to obtain a high frequency in the crystal unit, the thickness of the outer peripheral portion becomes very small and the mechanical strength is reduced by performing such processing. There was a risk of problems.

  Therefore, in the invention of Patent Document 1, as a method of manufacturing a crystal resonator in which spurious vibration is suppressed even at a high frequency, a recess is formed on the surface of the crystal substrate by wet etching, and the back surface of the crystal substrate is further ion-etched. , Reduce its thickness. Then, polishing is performed while applying pressure on the top and bottom of the quartz substrate, and the back surface of the concave portion is shaped into a convex lens shape to form a vibrating portion. By such a forming method, the outer peripheral region of the vibration part is configured as a holding part thicker than the vibration part.

  However, in this method, since one crystal substrate is etched, it is necessary to perform wet etching and ion etching to a depth of several tens to several hundreds of μm or more from the surface of the substrate in order to form a vibration surface. Thus, when the etching depth by wet etching or ion etching is large, the surface of the vibration part formed by the etching becomes rough, and as a result, the oscillation accuracy of the vibration part may be lowered. In Patent Document 1, it is described that the surface roughened by the ion etching can be removed by performing the polishing, but the surface side of the concave portion where the step is formed by the holding portion in the quartz substrate is Since such polishing cannot be performed, the roughness caused by wet etching cannot be removed, and the oscillation accuracy may not be sufficiently improved.

JP 2002-368572 (paragraph 0014 to paragraph 0019)

  An object of the present invention is to provide a method for manufacturing a piezoelectric vibrator capable of obtaining high oscillation accuracy and a piezoelectric vibrator manufactured by the method.

The method for manufacturing a piezoelectric vibrator of the present invention includes a step of etching the first piezoelectric substrate to form a through hole;
Forming an etching mask having a convex lens shape on one surface of the second piezoelectric substrate, the thickness of the central portion of which is larger than that of the peripheral portion;
One surface of the second piezoelectric substrate on which the etching mask is formed is etched to form a convex lens shape corresponding to the etching mask, and a vibrating portion is provided on each of the one surface side and the other surface side, each having an excitation electrode. Process,
Bonding the first substrate and the second piezoelectric substrate so that the vibrating portion is accommodated in the projection region of the through hole with respect to the second piezoelectric substrate;
Forming the excitation electrode on the vibrating portion;
Cutting the piezoelectric piece from the first piezoelectric substrate and the second piezoelectric substrate that are joined along the outer shape of the holding unit that surrounds the vibration unit and holds the vibration unit;
It is characterized by including.
For example, the second piezoelectric substrate is thinner than the first piezoelectric substrate, and the first piezoelectric substrate and the second piezoelectric substrate are, for example, quartz.

  The piezoelectric vibrator of the present invention is manufactured by the above-described manufacturing method.

  According to the present invention, an etching mask having a convex lens shape having a thicker central portion than its peripheral portion is formed on one surface of the second piezoelectric substrate, and the convex lens shape corresponding to the etching mask is formed. After forming the vibrating portion, the first piezoelectric substrate in which the through hole is formed is bonded to the second piezoelectric substrate to form a holding portion that holds the vibrating portion. Therefore, compared with a technique in which a concave portion whose outer periphery forms the holding portion is formed on one substrate by etching, and the vibration portion is formed by processing the front or back surface of the concave portion into a convex lens shape. Since the etching amount for forming the film can be suppressed, the surface roughness of the vibration part can be suppressed. Therefore, a decrease in oscillation accuracy of the piezoelectric vibrator can be suppressed.

  An example of a crystal resonator that is a piezoelectric resonator obtained by the manufacturing method of the present invention is shown in FIG. FIG. 1A shows the surface of the crystal unit 1. This crystal resonator 1 is composed of a crystal piece 1A, which is a square ring-shaped piezoelectric piece, and a plate-like crystal piece 1B, and the crystal piece 1B is bonded up and down so as to close the hole of the ring of the crystal piece 1A. It has a configuration with a rectangular recess 11 on its surface, and in FIGS. 1 (b) and 1 (c), a longitudinal section indicated by AA ′ of the crystal unit 1 in FIG. 1 (a), B Each of the longitudinal sections indicated by -B 'is shown. FIG. 1D shows the back surface of the crystal unit 1.

  An annular recess 12 is formed in the flat portion in the recess 11. The outer side wall and the inner side wall of the annular recess 12 are formed as curved surfaces with a narrower width on the lower side of the annular recess 12. Since the region surrounded by the annular recess 12 is the vibration portion 13 and the side wall of the annular recess 12 is formed as described above, the thickness of the vibration portion 13 on the center side is larger than the thickness on the peripheral side. And a large convex lens shape. Moreover, the roughness of the surface of the vibration part 13 of the crystal piece 1B in the recessed part 11 is 1 nm-1000 nm, for example.

  Further, the outer region of the annular recess 12 is configured as a holding portion 14 that is thicker than the vibrating portion 13 by bonding the crystal pieces 1A and 1B as described above. The holding unit 14 holds the vibrating unit 13 and improves the mechanical strength of the crystal unit 1 when the crystal unit 1 is handled, for example, when the crystal unit 1 is mounted in a package as will be described later. Formed to prevent its breakage. The thickness H1 of the crystal piece 1A is, for example, 100 μm to 500 μm, the thickness H2 of the center portion of the vibrating portion 13 of the crystal piece 1B is, for example, 10 μm to 100 μm, and the thickness H3 of the annular recess 12 is, for example, 0.5 μm to 10 μm.

  A pair of opposing excitation electrodes 15A and 15B for exciting the vibration part 13 are formed on the front and back surfaces of the vibration part 13, and the excitation electrodes 15A and 15B are substantially rectangular with their corners dropped. Is formed. Further, one corner of the excitation electrode 15A is drawn to the surface of the holding unit 14 through the side wall of the holding unit 14, and is further drawn to the outside of the crystal unit 1 on the surface. A portion extracted from the excitation electrode 15A is configured as an extraction electrode 16A that is electrically connected to an electrode formed in the package.

  One corner is also drawn from the excitation electrode 15B, and the lead portion is configured as a lead electrode 16B. The lead electrodes 16A and 16B are integrally formed with the excitation electrodes 15A and 15B, respectively. In this example, the excitation electrode 15B and the extraction electrode 16B are configured to have a shape in which the excitation electrode 15A and the extraction electrode 16A are turned upside down in plan view as shown in FIG.

  FIG. 2A shows the surface of a wafer W1 made of quartz that has been AT-cut from artificial quartz, for example. The wafer W1 is a first piezoelectric substrate (holding substrate), and the crystal piece 1A is formed from the wafer W1. The regions surrounded by dotted lines in the figure indicate the regions 21A to 24A where the crystal pieces 1A are respectively formed, and each region is a quadrangle surrounded by line segments parallel to the X axis and the Z ′ axis which are crystal axes of the wafer W. It is set as the area. The right side of the wafer W viewed from the front side with respect to the Z ′ axis is called the + Z direction, and the left side is called the −Z direction. When wet etching with hydrofluoric acid is performed, the + Z side is −Z side due to the anisotropy of quartz. Compared to the etching rate is slower.

  Actually, the crystal piece 1A is not limited to four regions 21A to 24A, but is set over the entire device formation region 25A surrounded by a chain line in the figure. A number of formation regions having the same size as these are set along the arrangement direction. Each process to be described later on the wafer W1 is performed on the entire device formation region 25A.

  FIG. 2B shows the surface of the wafer W2 made of quartz crystal that has been AT-cut from artificial quartz as in the case of the wafer W1. The wafer W2 is a second piezoelectric substrate (vibration substrate), and the crystal piece 1B is formed from the wafer W2. A region surrounded by a chain line in the figure is a device formation region 25B corresponding to the device formation region 25A. In the figure, regions 21B to 21 where crystal pieces 1B are formed corresponding to the crystal piece formation regions 21A to 24A of the wafer W1, respectively. Although 24B is illustrated by a dotted line, a large number of crystal piece 1B formation regions such as 21B to 24B are set over the entire device formation region 25B as in the device formation region 25A of the wafer W1, and will be described later. These processes are performed on the entire device formation region 25B. The quartz wafer W2 is thinner than the quartz wafer W1, for example, the quartz wafer W1 has a thickness of 100 μm to 500 μm, and the quartz wafer W2 has a thickness of 10 μm to 100 μm. The quartz wafers W1 and W2 are each cut out from the artificial quartz so as to have a thickness corresponding to the thickness of the holding part 14 and the vibrating part 13 to be formed.

  Next, a procedure for manufacturing the crystal unit 1 from the wafers W1 and W2 will be described. First, a process for processing the wafer W1 will be described. FIG. 3 shows a longitudinal section of the crystal piece 1A forming regions 21A and 22A along CC ′ in FIG. 2A, but these crystal piece forming regions 21A also in other crystal piece forming regions. , 22A, the process proceeds. First, a photoresist (hereinafter referred to as a resist) 31 as a mask material is formed on the surface of the wafer W1, and the resist film 31 is exposed along the shape of the holding portion 14 of the crystal resonator 1 (FIG. 3). (A), FIG.3 (b)). Thereafter, the resist film 31 is developed, and an opening 32 corresponding to the shape of the holding portion 14 is formed in the resist film 31 (FIG. 3C). FIG. 4A shows the surface of the wafer W1 when the opening 32 is formed. 4A, FIG. 4B, FIG. 6A, and FIG. 6B, which will be described later, show the resist film formed on the wafer with hatching for convenience of illustration. In the figure, the oblique line does not indicate a cross section.

  After the opening 32 is formed, a solution containing, for example, hydrofluoric acid is supplied to the surface of the wafer W, the wafer W is wet etched along the opening 32 using the resist film 31 as a mask, and the shape of the holding portion 14 is formed on the wafer W. A through-hole 33 corresponding to is formed (FIG. 3D). As described above, since the etching rate of the wafer W proceeds faster on the −Z side than on the + Z side, the side wall of the −Z side (left side in the figure) in the through hole 33 as shown in FIG. The verticality is lower than the verticality of the side wall on the + Z side (right side in the figure). FIG. 4B shows the surface of the wafer W1 when etching is performed in this way. After the etching is completed, the resist film 31 is removed (FIG. 3E).

  Next, a process for processing the wafer W2 will be described. FIG. 5 shows a longitudinal section of the formation region 21B, 22B of the crystal piece 1B along the line DD 'in FIG. 2B, but these crystal piece formation regions 21B, 22B also in other formation regions. The process proceeds in the same way. First, a resist film 41 is formed on the surface of the wafer W2 (FIGS. 5A and 5B), and the resist film 41 is exposed so as to substantially follow the outer periphery of the vibrating portion 14 of the crystal unit 1. Thereafter, the exposed resist film 41 is developed to form, for example, a square ring-shaped opening 42 in which the surface of the wafer W2 is exposed in the resist film 41 (FIG. 5C). FIG. 6A shows the surface of the wafer W2 in which the opening 42 is formed.

  Subsequently, the wafer W having the opening 42 formed in the resist film 41 is heated to dissolve the resist film 41, so that the surface of the wafer W is wetted and spread, and the concave portion 12 of the crystal resonator 1 is caused by the surface tension. And it shapes into the shape according to the vibration part 13 (FIG.5 (d)). That is, the side wall of the opening 42 is shaped into a curved surface so that the width of the opening 42 decreases toward the lower side, and the corner of the opening 42 is viewed from above as shown in FIG. Shaped to be round. Since the side wall of the opening 42 is shaped as described above, the region 43 for forming the holding portion 14 surrounded by the opening 42 has a convex portion with a thicker central portion than the peripheral portion. It becomes a mold lens shape.

  After the heated wafer W2 is cooled, the resist film 41 and the surface of the wafer W2 are etched by dry etching. As the resist film 41 and the wafer W2 are etched downward, the shape of the resist film 41 shaped as described above is transferred to the surface of the wafer W2, and the annular recess 12 and vibration described above are transferred to the wafer W2. A portion 13 is formed (FIG. 5E).

  Subsequently, as shown in FIG. 7, the back surface of the wafer W <b> 1 and the front surface of the wafer W <b> 2 are bonded so that the corresponding crystal piece forming regions overlap each other and the annular recess 12 and the vibrating portion 13 are included in the through hole 33. The recess 11 is formed and heated at a predetermined temperature. Then, by this heating, a siloxane bond (Si—O—Si) is formed between the wafer W1 and the wafer W2, and the wafer W1 and the wafer W2 are bonded to form a plywood W3 (FIG. 5F).

  Next, the processing steps performed in the plywood W3 will be described with reference to FIGS. In the figure, reference numerals 21 and 22 denote formation regions of the crystal unit 1, the formation region 21 includes the above-described crystal piece formation regions 21 </ b> A and 21 </ b> B, and the formation region 22 includes the above-described crystal piece formation regions 22 </ b> A and 22 </ b> B. It is a region formed by overlapping each other. FIGS. 8 and 9 show only these crystal resonator formation regions 21 and 22, but the subsequent processing is performed on the entire region formed by overlapping the device formation regions 25A and 25B on the plywood W3. .

  First, metal films 51 and 52 for forming the electrodes of the crystal unit 1 made of, for example, metal Cr (chromium) and Au (gold) are formed on the front and back surfaces of the wafer W by sputtering or vapor deposition, respectively. (FIGS. 8A and 8B). Although 51 and 52 are shown as a single metal film for convenience of illustration, Au is actually laminated on Cr. After the formation of the metal films 51 and 52, as shown in FIG. 8C, after the resist films 53 and 54 are formed on the metal films 51 and 52, respectively, the resist films 53 and 54 are respectively applied to the excitation electrode 15A. , 15B and the extraction electrodes 16A, 16B are exposed along the shape. Thereafter, the resist films 53 and 54 are developed, and openings 55 and 56 corresponding to the shapes of the excitation electrodes 15A and 15B and the extraction electrodes 16A and 16B are formed in the resist films 53 and 54 (FIG. 8). (D)).

  Subsequently, the metal films 51 and 52 are etched using the resist films 53 and 54 as a mask, respectively, so that the electrodes 15A and 16A are formed from the metal film 51, and the electrodes 15B and 16B are formed from the metal film 52, respectively (FIG. 8E). . Thereafter, the resist films 53 and 54 are removed (FIG. 9A), the plywood W3 is cut along the outer shape of each crystal resonator 1 by dicing or the like, and the crystal resonator 1 described above is cut from the plywood 3. Are formed in large numbers (FIG. 9B). The crystal resonator 1 may be cut out from the plywood W3 by etching.

  For example, the crystal unit 1 is shipped in a state of being mounted in a package 61 as shown in FIG. Lead electrodes 16A and 16B are connected to electrodes 62 and 63 in the package 61 through a conductive adhesive 65, respectively. The electrodes 62 and 63 are electrically connected to electrodes 66 and 67 provided on the lower surface of the package 61, and the electrodes 66 and 67 are electrically connected to an electronic component on which the crystal resonator 1 is mounted. The In the figure, reference numeral 68 denotes an adjustment member that is formed at the same height as the electrodes 66 and 67 and adjusts the height of the package 61.

  In such a manufacturing method of the crystal unit 1, the etching amount of the wafer W2 on which the holding unit 14 is formed can be suppressed by separately processing and bonding the wafer W1 and the wafer W2. Therefore, the etching amount required for forming the vibrating portion can be reduced as compared with a method in which a concave portion is formed by etching one substrate and the planar portion of the concave portion is configured as a vibrating portion. As a result, since the surface roughness of the vibration part 13 is suppressed, the oscillation accuracy of the vibration part 13 is increased and the occurrence of spurious is suppressed.

  It is preferable to cut out the wafer W2 from the artificial quartz so as to have a thickness corresponding to the thickness of the desired vibration portion in order to suppress surface roughness, but the wafer W2 is within the range not departing from the object of the present invention. The thickness of the vibrating portion 13 is controlled so as to obtain a desired resonance frequency by etching the surface and the back surface of the plywood W3 before forming the metal films 51 and 52. May be.

  As the excitation electrode 15A and the extraction electrode 16A that are upper electrodes formed on the surface side of the crystal unit 1, Ni (nickel), Au, Mo (molybdenum), and Al (aluminum) are used in addition to the above Cr and Au. , Ti (titanium), Pt (platinum), Cu (copper), Cr, or the like. Further, the excitation electrode 15B and the extraction electrode 16B, which are the lower electrodes, can be made of each metal that can be used as the upper electrode.

  In the above example, the wafers W made of AT-cut quartz are bonded together to form a crystal resonator that is a piezoelectric vibrator. However, the bonded quartz wafers are not limited to those that are AT-cut. In addition, the piezoelectric vibrator may be formed using a substrate made of ZnO (zinc oxide) or PZT (lead zirconate titanate) as a piezoelectric substrate instead of the quartz wafer. However, if the thermal expansion coefficients of the substrates to be bonded are different from each other, the piezoelectric vibrators formed due to the difference in thermal expansion coefficients may be distorted and affect the oscillation. Therefore, it is preferable to bond substrates made of the same material.

  In forming the through holes 33 in the wafer W1, dry etching may be performed instead of wet etching. Further, the extraction electrode 16A may be formed so as to be extracted in any direction of the crystal unit 1, but the lower the verticality of the side wall, the higher the metal coverage by sputtering or vapor deposition on the side wall. As in the example, forming the extraction electrode 16A so as to be extracted to the surface of the holding portion 14 through the side wall of the holding portion 14 on the side formed with low verticality increases the electric resistance of the extraction electrode 16A. It is preferable in order to prevent disconnection.

  Next, FIG. 11 shows a manufacturing example of another crystal resonator. A resist film 41 is formed on the back surface of the wafer W2 on which the annular recess 12 is formed as in the above-described embodiment, and the opening 42 is formed by performing the same patterning process as the process performed on the front surface. Then, the resist film 41 is shaped by heating (FIG. 11A), and etching is performed to form an annular recess 17 having the same shape as the annular recess 12 on the back surface (FIG. 11B). The recesses 12 and 17 are formed so that the cross sections thereof are vertically symmetrical. Accordingly, the vibrating portion 18 surrounded by the recesses 12 and 17 is formed in a convex lens shape whose thickness is higher at the center than at the peripheral edge thereof. . After the vibration part 18 is formed, the wafers W1 and W2 are bonded together as in the above embodiment (FIGS. 11C and 11D), and electrodes are formed on the front and back of the plywood W3 (FIG. 11E). The shape of the electrode is the same as that in the above-described embodiment. After the electrode formation, the plywood W3 is cut to divide each crystal resonator 1. Such a crystal resonator 1 also has an effect similar to that of the above-described embodiment because the etching amount of the vibrating portion 18 is suppressed.

  Moreover, as a vibration part of the crystal oscillator 1, it is good also as a structure as shown to Fig.12 (a) in which only the lower surface side swelled. When manufacturing such a crystal unit 1, the vibration unit 19 is formed by performing a series of steps from resist film formation to formation of the annular recess 17 by etching only on the lower surface side of the wafer W 2 as described above. . The vibration part 19 has a shape in which the vibration part 13 is turned upside down. Thereafter, the wafer W2 and the wafer W1 are bonded together so that the vibration part 19 is within the projection area of the through hole 33 onto the wafer W2. After the bonding, electrodes are formed in the same manner as in the above embodiment, and divided for each crystal resonator.

  Further, when the crystal unit 1 having the vibrating part 19 having the swelled back side is formed as described above, the periphery of the portion formed in the convex lens shape is the periphery of the recess 11 as shown in FIG. In this case, the region 70 that forms the bottom surface in the recess 11 surrounded by the chain line is formed by the excitation electrode formed in the same manner as in each of the above embodiments. Excited as

  Further, a resist mask is formed only on the region corresponding to the holding unit 13 on the wafer W2. That is, in the above-described embodiment, a resist film is formed only in the region 43 surrounded by the concave portion 12, heated, and shaped into a shape corresponding to the holding portion 43 as described above (FIG. 13A), and then etched. Then, the crystal unit 1 may be formed in the same manner as in the above embodiment (FIG. 13C). As described above, the height of the central portion of the vibration part may be higher than the height of the bonding surface between the substrates.

  In each of the above embodiments, the so-called thermal reflow method is used in which the resist is heated and shaped to form the vibrating portion 13 whose longitudinal section has a convex lens shape. I can't. For example, after the resist film 41 is formed on the wafer W2, as shown in FIG. 14A, exposure is performed through a mask 71 in which the transmittance is controlled according to the shape of the vibrating portion 13, and the resist film 41 is applied to the resist film 41. A so-called gray scale mask method is performed in which exposure is performed with different exposure amounts in the plane. Then, by performing development, the resist film 41 may be shaped so as to correspond to the vibrating portion 13 and the opening 42 corresponding to the annular recess 12 may be formed as shown in FIG. Further, when forming a resist mask having a convex lens shape on the wafer W2 in this way, a small amount of resist is discharged to a predetermined position by using, for example, an ink jet printer head, and the resist is applied to the wafer W2 by its surface tension. A so-called inkjet method in which a film is formed in a convex lens shape may be used.

1 is a configuration diagram of a crystal resonator according to the present invention. It is a surface view of each wafer for forming the crystal resonator. It is process drawing in which the crystal piece which comprises the said crystal oscillator from a wafer is manufactured. It is a surface view of the wafer in the said process. It is process drawing in which the crystal piece which comprises the said crystal oscillator from a wafer is manufactured. It is a surface view of the wafer in the said process. It is a perspective view of each wafer bonded together. It is process drawing which manufactures the said crystal oscillator from the plywood with which the wafer was bonded together. It is process drawing which manufactures the said crystal oscillator from the plywood with which the wafer was bonded together. It is a vertical side view of the crystal resonator enclosed in a package. It is process drawing which shows the manufacturing process of another crystal oscillator. It is the vertical side view which showed the structural example of the other crystal oscillator. It is the vertical side view which showed the structural example of the other crystal oscillator. It is process drawing which showed the other structure method of the holding | maintenance part.

Explanation of symbols

W1, W2 Substrate W3 Plywood 1 Crystal resonator 1A, 1B Crystal piece 13 Vibrating portion 14 Holding portion 15A, 15B Excitation electrode 16A, 16B Extraction electrode 21A-24A, 21B-24B Crystal piece forming region 25A, 25B Device forming region 41 Resist film

Claims (4)

Etching the first piezoelectric substrate to form a through hole;
Forming an etching mask having a convex lens shape on one surface of the second piezoelectric substrate, the thickness of the central portion of which is larger than that of the peripheral portion;
One surface of the second piezoelectric substrate on which the etching mask is formed is etched to form a convex lens shape corresponding to the etching mask, and a vibrating portion is provided on each of the one surface side and the other surface side, each having an excitation electrode. Process,
Bonding the first substrate and the second piezoelectric substrate so that the vibrating portion is accommodated in the projection region of the through hole with respect to the second piezoelectric substrate;
Forming the excitation electrode on the vibrating portion;
Cutting the piezoelectric piece from the first piezoelectric substrate and the second piezoelectric substrate that are joined along the outer shape of the holding unit that surrounds the vibration unit and holds the vibration unit;
A method for manufacturing a piezoelectric vibrator, comprising:   The method for manufacturing a piezoelectric vibrator according to claim 1, wherein the second piezoelectric substrate is thinner than the first piezoelectric substrate.   3. The method of manufacturing a piezoelectric vibrator according to claim 1, wherein the first piezoelectric substrate and the second piezoelectric substrate are quartz.   A piezoelectric vibrator manufactured by the manufacturing method according to claim 1.

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