Piezoelectric vibrating piece and piezoelectric vibrator

Abstract

To prevent vibration from becoming unstable due to followability of vibration (amplitude).SOLUTION: A piezoelectric vibrating piece is removed by non-thermal processing rather than by melting and removing the entire predetermined region (total thickness) of a weight film 75 provided at the tip of a vibrating arm 7. When the weight film 75 is removed by non-thermal processing, an inclined portion B is formed so as to be become gradually thinner along the longitudinal direction. The end of the inclined portion B on the opposite side from a first thickness portion C is continuous with a second thickness portion A, which is removed so as to be thinner than the first thickness portion C by non-thermal processing. The weight film 75 is removed not by melting but by non-thermal processing by directly irradiating the weight film 75 with a non-thermal processing laser Lf. Here, as the non-thermal processing laser Lf, a laser having a pulse width capable of non-thermal processing of the weight film 75, that is, a pulse width of picoseconds (within two digits) to femtoseconds, for example, a femtosecond laser is used.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a piezoelectric vibrating piece and a piezoelectric vibrator, and more particularly to a technique using a tuning fork type crystal. [Background technology]

[0002] For example, in electronic devices such as mobile phones and personal digital assistants, piezoelectric vibrators using a piezoelectric vibrating piece formed into a tuning fork shape are used as devices used as a time source, a timing source for control signals, a reference signal source, etc. In such tuning fork-type piezoelectric vibrating pieces, a metal weight film is formed at the tip of the vibrating arm, and the frequency is adjusted by trimming this film (for example, Patent Document 1). That is, the piezoelectric vibrating piece mounted on a package is oscillated, and while the frequency is being measured, a laser with a pulse width of about nanoseconds is irradiated to melt and remove the weight film, thereby trimming it to reduce its mass, thereby adjusting the frequency (Patent Document 1). When trimming with this laser, the surface of the weight film to be melted is placed downward, and the laser is applied to the top side of the piezoelectric vibrating piece (the side opposite the weight film) so that the melted and removed weight film is received in a recessed area on the bottom of the package.

[0003] FIG. 8 shows the state of the tip of the vibrating arm after the weight film has been melted and removed using a conventional laser. As shown in Figure 8, in conventional trimming, the entire weight film in the area irradiated with the laser is removed, which results in a steep step between the remaining weight film part and the removed part, resulting in poor vibration (amplitude) tracking and unstable vibration. Furthermore, in the conventional frequency adjustment using a laser, the weight film 750 in the area irradiated with the laser Ln is entirely melted and removed, so that it is not possible to further improve the frequency adjustment accuracy. In particular, in the case of small piezoelectric vibrating pieces of 3 mm x 2 mm or less, the area of ​​the weight film to be trimmed is small, so finer and more accurate trimming is required for frequency adjustment.

[0004] Furthermore, in conventional frequency adjustment, as shown in FIG. 8, the weight film 750 is melted and removed by the laser Ln, and debris 751, 752 is generated on the main surface and side surfaces around the weight film 750 remaining after the melting and removal. For example, if the spot diameter of the laser Ln is 20 μm, the width w1 of debris generation is approximately the same, i.e., 20 μm, which is large, causing imbalance between the left and right sides of the longitudinal center line P. In the example shown in FIG. 8(b), the amount of debris generated on the left side of the longitudinal center line P is greater than that on the right side. The debris 751, 752 is generated not only on the left and right of the center line P of the vibrating arm, but also in different amounts on both vibrating arms, which causes the balance of the vibrating arms to be lost, resulting in a problem of adverse effects due to vibration leakage.

[0005] Furthermore, since the weight film 750 melts in a downward position, the debris 751 formed on the main surface is turned up as shown in FIG. 8(a), and the debris 751 is then dislodged by vibration. teeth If the debris falls due to vibration, it could upset the balance between the left and right vibrating arms and affect the frequency due to changes in weight. In general, the smaller the piezoelectric vibrating piece, the thicker the weight film 750 must be to ensure the weight, and this makes it easier for debris 751 to be generated when the weight film 750 is melted and removed by the laser Ln. For this reason, the smaller the piezoelectric vibrating piece, the greater the issues such as imbalance of the left and right sides due to debris and vibration leakage. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2003-133879 A Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to suppress instability in vibration due to vibration (amplitude) tracking in a tuning-fork type piezoelectric vibrating piece. [Means for solving the problem]

[0008] (1) The invention described in claim 1 is a piezoelectric vibrating piece formed in a tuning fork shape from quartz crystal, which is mounted in a package having a mounting portion on the inside, and includes a base, a pair of vibrating arms extending from the base in parallel, two systems of electrodes formed on the pair of vibrating arms, and a metal formed at the tip of the vibrating arms. Around A weight film for adjusting wave number; The weight membrane has a first thickness portion, a planar first inclined surface formed on at least one of the base side and the tip side of the first thickness portion and having a thickness gradually thinner than that of the first thickness portion, and a first curved surface curved in a convex shape that continuously connects the first thickness portion and the first inclined surface. The present invention provides a piezoelectric vibrating piece having the following features. (2) In the invention described in claim 2, The piezoelectric vibrating piece according to claim 1, characterized in that the first inclined surface is formed so that an end portion opposite the first thick portion abuts against a quartz crystal surface of the vibrating arm portion. (3) In the invention described in claim 3, The present invention provides a piezoelectric vibrating piece as described in claim 1, characterized in that the weight film has a second thickness portion formed thinner than the first thickness portion, and the first inclined surface is continuous with the second thickness portion on the side opposite to the first thickness portion. (4) In the invention described in claim 4, 4. The piezoelectric vibrating piece according to claim 3, wherein a second curved surface that is curved in a concave shape is formed at a connection portion between the first inclined surface and the second thick portion. (5) In the invention described in claim 5, The present invention provides a piezoelectric vibrating piece as described in claim 3 or claim 4, characterized in that the weight membrane has a planar second inclined surface facing the first inclined surface and formed on the side of the second thickness portion opposite the first inclined surface, and a third thickness portion formed on the side of the second inclined surface opposite the second thickness portion and thinner than the first thickness portion and thicker than the second thickness portion. (6) In the invention described in claim 6, The present invention provides a piezoelectric vibrating piece as described in any one of claims 1 to 5, characterized in that the weight film is formed on both sides of the vibrating arm portion, and the first thickness portion, the first inclined surface, and the first curved surface are formed on at least one of the surfaces. (7) The invention described in claim 7 is characterized in that the piezoelectric element is a side arm type mounted on the mounting part by a supporting arm portion formed by extending from the base to the outside of the vibrating arm portion, a center arm type mounted on the mounting part by a single supporting arm portion formed by extending from the base to between the vibrating arms, or a cantilever type mounted on the mounting part by the base. 6 The present invention provides a piezoelectric vibrating piece according to any one of claims 1 to 5. (8) The invention described in claim 8 includes a package having a mounting portion on the inside, and a semiconductor device mounted on the mounting portion. 7 The present invention provides a piezoelectric vibrator comprising: a piezoelectric vibrating piece according to any one of claims 1 to 5; and an external electrode portion formed from the mounting portion to the outside of the package. Effect of the Invention

[0009] According to the present invention, a weight film is formed at the tip of the vibrating arm. but, The first thickness portion and The first inclined surface has a flat shape, the thickness of which gradually becomes thinner than that of the first thick portion, and a first curved surface that is curved in a convex shape and continuously connects the first thick portion and the first inclined surface. This leads to a steep Thickness change Since the vibration is reduced, the vibration can be more stabilized. [Brief description of the drawings]

[0010] [Figure 1] 4 is an explanatory diagram showing the shape of a weight film formed at the tip of a vibrating arm of a piezoelectric vibrating piece. FIG. [Diagram 2] 13 is an explanatory diagram of a method for removing a weight film using a non-thermal processing laser Lf. FIG. [Diagram 3] 13 is an explanatory diagram showing the state in which a part of the weight film has been removed by the non-thermal processing laser Lf. FIG. [Figure 4] 13A and 13B are explanatory diagrams showing modified shapes of weight films formed at the tips of the vibrating arms. [Diagram 5] FIG. 11 is an explanatory diagram showing the shape of a weight membrane in the second embodiment. [Figure 6] FIG. 2 is an exploded perspective view of a piezoelectric vibrator housing a piezoelectric vibrating piece. [Figure 7] 11A to 11C are explanatory diagrams of other shapes of the piezoelectric vibrating reed. [Figure 8] 11 is an explanatory diagram showing the state of the tip of the vibrating arm after the weight film has been melted and removed by a conventional laser. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to FIGS. (1) Overview of the embodiment In the piezoelectric vibrating piece of the present embodiment, the weight film 75 provided at the tip of the vibrating arm portion 7 (7a, 7b) is removed by non-thermal processing, rather than by melting and removing the entire predetermined area (total thickness). When the weight film 75 is removed by non-thermal processing, the removed end (the end in the longitudinal direction of the vibrating arm 7) is formed so as to gradually become thinner along the longitudinal direction. That is, a sloped portion B is formed in which the thickness gradually becomes thinner in continuation with the original thickness portion (first thick portion C). The end of the inclined portion B on the side opposite to the first thickness portion C is in contact with the vibrating arm portion 7 or is continuous with the second thickness portion A that has been removed to be thinner than the first thickness portion C by non-thermal processing. As a result, the weight film 75 has different thicknesses and inclined surfaces formed in different regions, and is formed into a shape with inclined steps. The weight film 75 is removed by non-thermal processing by directly irradiating the weight film 75 with a non-thermal processing laser Lf instead of melting and removing. Here, as the non-thermal processing laser Lf, a laser having a pulse width capable of non-thermal processing of the weight film 75, that is, a laser with a pulse width in picoseconds (two digits or less, for example, 15 picoseconds) to femtoseconds, for example, a femtosecond laser is used.

[0012] By using this non-thermal processing laser Lf, the upper surface side is removed while leaving a thickness of nμm (n < N) with respect to the thickness Nμm of the weight film 75 before processing to form the second thickness portion A, and an inclined portion B with a gradually decreasing thickness is formed between the first thickness portion C (thickness Nμm), which is the unprocessed portion, and the second thickness portion A. In the second thickness portion A, the thickness to be removed is adjusted by the number of times the region is scanned with the non-thermal processing laser Lf and / or the pulse width. On the other hand, in the inclined portion B, it is formed by reducing the number of scans, reducing the pulse width, or reducing the output energy as going from the second thickness portion A side to the first thickness portion C side.

[0013] In this way, by non-thermal processing using the non-thermal processing laser Lf, an inclined portion B continuous with the first thickness portion C is formed on the weight film 75 for frequency adjustment, so that the presence of steep steps is reduced. That is, by making the cross-sectional shape of the weight film 75 into a shape with inclined steps, the vibration can be more stabilized. In addition, the formation of the second thickness portion A enables highly accurate frequency adjustment and can increase the frequency accuracy of the piezoelectric vibrating piece 6. In addition, since the non-thermal processing is performed by the non-thermal processing laser Lf, it is possible to prevent the generation of debris due to melting and removal. This allows the frequency adjustment to be balanced not only for each vibrating arm 7 but also between both vibrating arms 7a and 7b, and suppresses vibration leakage. Furthermore, since there is no debris on the weight film 75 after the frequency adjustment, it is possible to prevent the frequency from changing due to debris being dislodged by vibration.

[0014] (2) Details of the First Embodiment The first embodiment is a tuning-fork-type piezoelectric vibrating piece 6 that uses quartz crystal, the details of which will be described later in FIG. 6. A pair of vibrating arms 7 (7a, 7b) extend from a base 8, and supporting arms 9 (9a, 9b) are formed to support the piezoelectric vibrating piece 6 within a package 2. A groove 72 of a certain width is formed on the main surface (rear surface) of the pair of vibrating arms 7 in the longitudinal direction. Two different excitation electrodes 91, 92 functioning as a first excitation electrode and a second excitation electrode are formed on the side surface and main surface constituting the outer circumferential surface of the vibrating arm 7, and in the groove 72. Incidentally, it is possible not to form the grooves 72 in the vibrating arm portion 7, including in each of the modified examples described later, but in the case where the grooves 72 are not formed, the first and second excitation electrodes are formed on the main surface. A weight film 75 for adjusting frequency is formed at the tip of the vibrating arm 7 in the longitudinal direction (on the tip side beyond the groove 72).

[0015] Fig. 1 shows the shape of the tip of a vibrating arm 7 in a piezoelectric vibrating piece according to this embodiment. Note that Figs. 1 to 5 show one tip of a pair of vibrating arms 7. The filled-in parts in each figure represent the weight film 75 except for Fig. 5, and represent the cross section of the weight film 75 in Fig. 5. As shown in FIG. 1, a weight film 75 for frequency adjustment is formed over the entire main surface at the tip of the vibrating arm portion 7. This weight film 75 is made of a metal material such as Au or Ag, and is formed to a predetermined thickness of N μm by various methods such as vacuum deposition. In the present embodiment, the weight film 75 is formed to a predetermined thickness of N μm = 3 μm. However, the thickness N μm is appropriately selected according to various conditions such as the size of the piezoelectric vibrating piece to be manufactured, various forms such as the center arm type described later, and whether the tip of the vibrating arm portion 7 is widened in the lateral direction (the size of the formation region of the weight film 75). In the present embodiment, the weight film 75 is formed only on one main surface. However, since the non-thermal processing laser Lf is directly irradiated onto the weight film 75, it is also possible to form it on both surfaces or side surfaces.

[0016] As shown in FIGS. 1(a) and 1(b), the weight film 75 at the tip of the vibrating arm portion 7 according to the present embodiment is formed with a second thickness portion A, an inclined portion B, and a first thickness portion C from the tip side in the longitudinal direction toward the base portion 8 side (the left side in the drawing, see FIG. 6). As shown in FIG. 1(b), the first thickness portion C is a region where the film has not been processed by the non-thermal processing laser Lf and remains at the initial thickness of N μm. On the other hand, the inclined portion B and the second thickness portion A are portions where a part of the weight film 75 has been removed by the processing of the non-thermal processing laser Lf. By using the non-thermal processing laser Lf, it is possible to remove the entire thickness or only a part of the thickness in the thickness direction of the weight film 75. In the present embodiment, only a part is removed. The second thickness portion A is a portion that has been removed in parallel with the main surface of the vibrating arm portion 7, leaving a thickness of n μm (n < N). Since this second thickness portion A is located on the tip side of the vibrating arm portion 7, it is a portion where a part of the weight film 75 has been removed during frequency adjustment as described later.

[0017] The inclined portion B is formed with an inclined surface whose thickness gradually decreases from the base portion 8 side toward the tip side by being continuous with the first thickness portion C on the base portion 8 side and continuous with the second thickness portion A on the tip side. This inclined portion B is a portion for adjusting the frequency by removing part of the weight film 75, and for stabilizing the vibration by the vibrating arm portion 7 by eliminating the steep step that occurs between the first thickness portion C and the second thickness portion A.

[0018] As shown in FIG. 1(c), the inclination angle θ of the inclined portion B is in the range greater than 0 degrees and smaller than 90 degrees (0°<θ<90°). This inclination angle θ is determined by the value (Nn) obtained by subtracting the thickness n of the second thick portion A from the thickness N of the first thick portion C, and the length in the longitudinal direction of the inclined portion B. In reality, the thickness (Nn) at the time of forming the inclined portion B is a specified value, so the inclination angle θ is determined by the length. The length of the inclined portion B in the longitudinal direction may be narrower than 1 / 2 the spot diameter p1 of the laser light by the non-thermal processing laser Lf, but is preferably p / 2 or more, and more preferably in the range of 1 to 2 times the spot diameter p1. The length of the inclined portion B is preferably a fixed width selected and a preset value that does not change depending on the amount of frequency adjustment (i.e., the removal weight is also a specified weight).

[0019] On the other hand, the longitudinal lengths of the second thick portion A and the first thick portion C each change depending on the frequency adjustment amount. That is, the length of the second thick portion A is determined by subtracting the specified weight to be subsequently removed in the inclined portion B from the weight of the weight film 75 to be removed, which is determined according to the frequency adjustment amount. The length of the first thick portion C is the length after the second thick portion A and the inclined portion B are removed.

[0020] Piezoelectric vibrators are formed in various sizes, but the effect of this embodiment is particularly pronounced in smaller piezoelectric vibrators housing piezoelectric vibrating pieces, such as 2.0 mm×1.2 mm, 1.6 mm×1.0 mm, and 1.2 mm×1.0 mm. The piezoelectric vibrating piece is formed according to the size of the piezoelectric vibrator. For example, in the case of a piezoelectric vibrator of 1.6 mm×1.0 mm size, the piezoelectric vibrating piece is formed to have a length of approximately 1 mm, a width of 0.5 mm, and a thickness of 0.1 mm. On one hand, at the tip of the vibrating arm portion 7, in the state before frequency adjustment by the non-thermal processing laser Lf, the weight film 75 is formed to have a thickness of N = 3 μm which is the thickness of the first thickness portion C, and the area and thickness of the weight film 75 to be scraped off are determined according to the adjustment amount of the required frequency for each region.

[0021] For the tuning fork type piezoelectric vibrating piece, the frequency sensitivity increases from the base side to the tip side of the vibrating arm portion 7. Therefore, in frequency adjustment, it is efficient to perform coarse adjustment on the region on the tip side of the weight film 75 and fine adjustment on the region on the base 8 side. In the present embodiment, as shown in FIG. 1(b), the frequency adjustment is completed by deleting the second thickness portion A and the inclined portion B. However, when further fine adjustment of the frequency is performed after the frequency adjustment by deleting the second thickness portion A and the inclined portion B, it is performed by deleting the base 8 side of the first thickness portion C. In this case, only an inclined portion (an inclination opposite to the inclined portion B) may be formed on the base 8 side, or a third thickness portion having a thickness of n2 μm (n2 < N) and an inclined portion may be formed. Also, the frequency can be coarsely adjusted by further deleting the tip of the weight film 75 until the main surface of the vibrating arm portion 7 is exposed, and fine adjustment can be performed by the second thickness portion A and the inclined portion B before that. In this case, it is also possible to form an inclined portion between the tip side of the second thickness portion A and the main surface of the vibrating arm portion 7, thereby further reducing the steep step. Details of various modifications to the embodiment shown in FIG. 1 will be described later.

[0022] Next, a processing method of the weight film 75 formed at the tip of the vibrating arm portion 7 according to the present embodiment will be described. FIG. 2 is an explanatory diagram of a method for deleting the weight film 75 by the non-thermal processing laser Lf, where FIG. 2(a) is a plan view, and FIGS. 2(b) to 2(d) are cross-sectional views in the longitudinal direction. As shown in Fig. 2(a), a weight film 75 having a predetermined thickness N (=3 μm) is formed on the tip of the vibrating arm 7. The weight film 75 of the present embodiment shown in Fig. 2 is formed on one of the main surfaces of the vibrating arm 7, but it may be formed on both sides or on the entire periphery including the side surfaces. This weight film 75 is faced upward, and as shown in FIG. 2(b), a non-thermal processing laser Lf is irradiated directly onto the weight film 75 (without passing through the vibrating arm portion 7), thereby removing a predetermined thickness (Nn) μm of the weight film 75 by non-thermal processing. The non-thermal processing laser Lf used in this embodiment is, for example, a femtosecond laser with a wavelength of 515 nm, a spot diameter p1 = 10 μm, and a pulse width of 100 fs. This non-thermal processing laser Lf is scanned back and forth in the width direction and in the length direction at a movement pitch p2 (for example, p2 = p1 / 2 = 5 μm) to remove a predetermined area of ​​the weight film 75. In FIG. 2(a), the circle shown at the tip of the weight film 75 represents the spot diameter p1 of the non-thermal processing laser Lf, and shows a state in which the weight film 75 is moving in the width direction at the movement pitch p2 so that a part of the spot of p1 overlaps. Then, the weight film 75 in a predetermined area is removed by moving in the length direction while moving in the width direction at the movement pitch p2.

[0023] In this trimming process, the non-thermal processing laser Lf is scanned in the area A where the second thickness portion A is to be formed, and the frequency is adjusted by removing a thickness (Nn) μm from the thickness N μm of the weight film 75. At this time, the frequency is gradually driven to the target frequency by repeatedly measuring the deviation from the target frequency by frequency measurement and removing the area (weight) according to the deviation. In this embodiment, the weight is removed in the area A taking into account the weight of the inclined portion B to be formed following the formation of the second thickness portion A. If the deviation from the desired frequency (target frequency) is large, this can be dealt with by widening area A of second thickness portion A and making the thickness thinner. If the deviation is even larger, the weight film 75 at the most distal end, which has a greater effect on frequency adjustment, is completely removed up to the main surface of the vibrating arm 7, and a portion of the front side of the completely removed portion is removed to form the second thickness portion A and the inclined portion B, allowing for finer adjustment. If even finer adjustment is required, the frequency can be fine-tuned by removing the weight film 75 on the base 8 side.

[0024] After the removal of the second thick portion A is completed, as shown in FIG. 2(c), a sloped portion B having a sloped surface is formed between the second thick portion A and the first thick portion C. FIG. 2(d) is an enlarged view showing the state in which the inclined portion B is formed. As shown in FIG. 2(d), the actual inclined portion B is not a flat plane, but is formed by small steps (at least two or more steps between the first thick portion C and the second thick portion A) and slopes. The continuous small steps in this inclined portion B are formed by using the upper processing side surface with the non-thermal processing laser Lf and by changing the number of scans. R do.

[0025] In FIG. 2(d), the number in parentheses after the non-thermal processing laser Lf indicates the number of round trips required to scan one line. For example, Lf(3) indicates that the line is scanned three times. 2(d), for example, the non-thermal processing laser Lf(3) is scanned three times back and forth on each line to form the second thickness portion A. After that, on a line moved by a predetermined movement pitch p3, the non-thermal processing laser Lf(2) is scanned two times back and forth, and the line moved by a further movement pitch p3 is scanned one time back and forth with the non-thermal processing laser Lf(1). As a result, a small step is formed between the second thickness portion A formed by three reciprocating scans and the unprocessed first thickness portion C by two reciprocating scans and one reciprocating scan, suppressing abrupt thickness changes.

[0026] Furthermore, the upper and lower portions of each step have slightly curved inclined surfaces, which further suppress abrupt thickness changes caused by small steps. For example, in processing using the non-thermal processing laser Lf, as shown in the cross section of Figure 2(d), the processing end is not perpendicular to the processing surface (the surface on the irradiated side), but a slightly inclined surface (curved surface) is formed due to the energy distribution. This inclined surface is convexly curved on the upper side of the processing end and concavely curved on the lower side (the vibrating arm 7 side). Part of the inclined part B is formed by using the upper and lower curved surfaces. However, in FIG. 2(d), the inclined surface outside the spot diameter is exaggerated in order to conceptually explain it.

[0027] In the example shown in Fig. 2(d), the number of longitudinal movements (number of movements at the movement pitch p3) by the non-thermal processing laser Lf(2) and the non-thermal processing laser Lf(1) is one each, but by increasing the number of movements, it is possible to adjust the inclination angle θ shown in Fig. 1(c) to be smaller. Also, by narrowing the movement pitch p3 by the non-thermal processing laser Lf or omitting either the non-thermal processing laser Lf(2) or the non-thermal processing laser Lf(1), it is possible to adjust the inclination angle θ to be larger.

[0028] FIG. 3(a) shows a side cross section and (b) shows a top view of the state in which a part of the weight film 75 has been removed by the non-thermal processing laser Lf. Conventional lasers Ln with pulse widths of nanoseconds to picoseconds (three digits) melt and remove the entire weight film in the irradiated area using heat, which generates debris at the boundary surface of the irradiated area, as shown in Figure 8. This makes it difficult to adjust the frequency of the smaller piezoelectric vibrating reed and can cause the balance between the vibrating arms to be lost, resulting in vibration leakage. In contrast, the non-thermal processing laser Lf of this embodiment irradiates the surface of the weight film 75 with a femtosecond pulse laser, causing the solid constituent materials to become atoms, molecules, or plasma and be explosively released (ablation), removing them through non-thermal processing. 3(a), it is possible to remove a part of the thickness direction of the weight film 75 in the irradiation area of ​​the non-thermal processing laser Lf to form the second thickness part A and the inclined part B. As a result, it is possible to perform high-precision frequency adjustment even for a smaller piezoelectric vibrating piece.

[0029] Furthermore, as shown in FIG. 3(b), since no debris is generated at the boundaries of the irradiation area of ​​the non-thermal processing laser Lf, the roughness of the widthwise boundary surface at the boundary between the second thickness portion A and the inclined portion B and the boundary between the inclined portion B and the first thickness portion C (the variation width of the processed edge due to irradiation with the non-thermal processing laser Lf with respect to a virtual straight line in the widthwise direction perpendicular to the center line P) is suppressed to approximately half the spot diameter of the non-thermal processing laser Lf. In this embodiment, as described above, a non-thermal processing laser Lf with a spot diameter of 10 μm is used, so the actual variation width w2 is suppressed to approximately 5 μm, which is significantly suppressed compared to the conventional width w1 = 20 μm shown in Figure 8. In this way, according to this embodiment, it is possible to prevent the generation of debris, and also to achieve left-right balance with respect to the center line P of the vibrating arm 7, and balance between both vibrating arms 7. By using this piezoelectric vibrating piece, a piezoelectric vibrator with less vibration leakage can be formed. The variation width of the boundary surface depends on the spot diameter and movement pitch p2 of the non-thermal processing laser Lf, but from the viewpoint of improving the balance accuracy of the vibrating arm portion 7 and suppressing vibration leakage, the variation width w2 is set to 10 μm or less, preferably 5 μm or less.

[0030] Next, a modification of the weight membrane 75 of this embodiment will be described. In the embodiment described in Figure 1, the second thickness portion A, the inclined portion B, and the first thickness portion C are formed by irradiating a non-thermal processing laser Lf from a direction perpendicular to (above) the formation surface of a weight film 75 of a predetermined thickness N formed on the main surface of the tip of the vibrating arm portion 7. In response to this, the following modifications (a) to (e) and various other modifications that combine these are possible. Modification (a) The inclined surface of the inclined portion B is formed so as to face the base portion 8 (see FIG. 6) side, not the tip side. Modification (b) The lower end of the inclined portion B is formed to abut against the crystal. In other words, the weight film 75 on the tip side / base portion 8 side of the lower end of the inclined portion B is completely removed up to the main surface of the vibrating arm portion 7. Deformation (c) A plurality of inclined portions B are formed. The deformation (ii) weight film 75 is formed so that there are three or more different thicknesses excluding the inclined portion B. In this case, a plurality of inclined portions B are necessarily formed. A deformation (e) weight film 75 is formed on both sides, and an inclined portion B is formed on at least one of the sides.

[0031] FIG. 4 shows the shape of a weight membrane 75 according to a modification that employs one or more of the above modifications (a) to (e). Fig. 4(a) shows a case where the above-mentioned modification (ii) is adopted, which is formed by completely removing the second thickness portion A formed on the tip side of the weight film 75 shown in Fig. 1. For example, in the tip side scan described in Fig. 2(d), the number of round trips of the femtosecond laser Lf is increased from three to four or more (four in the case of Fig. 2(d)), thereby completely removing the weight film 75 in the region A.

[0032] FIG. 4(b) shows the case where the above modification (i) is adopted. In the example of Figure 4(b), the scan is moved from the base 8 side of the weight membrane 75 toward the tip side, and a second thick portion A is formed on the base 8 side, and then an inclined portion B facing the base 8 side is formed. 2, including all modified examples, a case has been described in which the thinner portion (e.g., second thickness portion A) is first engaged and then the inclined portion B is formed toward the thicker portion (e.g., first thickness portion C), but the reverse is also possible. That is, in the example of FIG. 2(d), the inclined portion B may be formed from the top to bottom starting from the first thickness portion C side of the thicker portion using the non-thermal processing laser Lf(1) and then the non-thermal processing laser Lf(2), and then the second thickness portion A may be formed.

[0033] FIG. 4(c) shows a case where the above-mentioned modification (iii) and modification (a) are adopted. In the example of Figure 4(c), second thickness portions A are formed in two locations on both sides, the tip side and the base 8 side, and inclined portions B1 and B2 facing in opposite directions are formed from both second thickness portions A toward the central first thickness portion C. In the example of Fig. 4(c), the non-thermal processing laser Lf is moved from the tip side to the base 8 side, thereby skipping the second thickness portion A, inclined portion B1, and first thickness portion C on the tip side, and forming the inclined portion B2 and the second thickness portion A. Alternatively, after forming the second thickness portion A and inclined portion B1 on the tip side in that order, the position and moving direction of the non-thermal processing laser Lf may be changed to form the second thickness portion A and inclined portion B2 on the base 8 side. In addition, in the modified example shown in Figure 4 (c), by applying modification (ii), it is possible to completely remove at least one of the second thick portion A on the tip side and the second thick portion A on the base 8 side.

[0034] FIG. 4(d) shows a case where the above-mentioned modification (iii) and modification (a) are adopted. Figure 4(d) is the opposite of the modified example (c), in that a second thick portion A is formed in one central location, and oppositely oriented inclined portions B1 and B2 are formed on either side of it, and a first thick portion C is formed in two locations on the outside (the tip side and the base 8 side).

[0035] FIG. 4(e) shows a case where the above-mentioned modifications (c), (a), and (d) are adopted. In FIG. 4(e), like the modified example in (c), an inclined portion B1 and an inclined portion B2 are formed on the tip side and the base 8 side of the first thick portion C formed in the center, but the difference from (c) is that a second thick portion A2 is formed on the base 8 side, and a second thick portion A1 (third thick portion) that is thicker than the second thick portion A2 is formed. destination The second thick portion A1 may be formed on the base 8 side and the second thick portion A1 may be formed on the tip side.

[0036] FIG. 4(f) shows the case where the above-mentioned modifications (a), (c), and (d) are adopted. 4(f), a first thick portion C, an inclined portion B1, a second thick portion A1, an inclined portion B2, and a second thick portion A2 are formed in this order from the tip side toward the base portion 8. As shown in the figure, in this modified example, the inclined portion B1 and the inclined portion B2 are formed in two places in the same direction (toward the base portion 8). In addition, the order of forming the first thick portion C to the second thick portion A2 shown in Figure 4 (f) may be reversed, and the second thick portion A2, the inclined portion B2, the second thick portion A1, the inclined portion B1, and the first thick portion C may be formed in that order from the tip side toward the base portion 8.

[0037] FIG. 4(g) shows the case where the above-mentioned modifications (a) and (e) are adopted. In the modified example of Figure 4(g), a first thick portion C1, an inclined portion B1, and a second thick portion A1 are formed on one main surface from the tip side of the vibrating arm portion 7 toward the base portion 8, and a first thick portion C2, an inclined portion B2, and a second thick portion A2 are formed on the other main surface. Although the second thick portion A1 on one side and the second thick portion A2 on the other side have the same thickness, one of them may be formed to be thicker than the other. Also, the order of forming the second thick portion A, the inclined portion B, and the first thick portion C may be reversed, so that the first thick portion C is formed on the base portion 8 side.

[0038] Next, a second embodiment of the shape of the weight membrane 75 will be described. In the first embodiment, a case has been described in which the inclined surface of the inclined portion B faces the longitudinal direction of the vibrating arm portion 7 (see FIG. 2). In contrast to this, in the second embodiment, the inclined surface of the inclined portion B is formed by an inclined surface in the longitudinal direction of the vibrating arm portion 7 and an inclined surface in a direction inclined relative to the longitudinal direction. 5 is an explanatory diagram showing the shape of the weight film 75 in the second embodiment. Fig. 5(a) shows the plane of the tip of the vibrating arm 7 on which the weight film 75 is formed, (b) shows the P1-P1 step surface along the longitudinal direction, (c) shows the P2-P2 step surface along the longitudinal direction, and (d) shows the P3-P3 step surface along the width direction. In the cross sections of (b) to (d), the cross-sectional portions of the weight film 75 are shown filled in.

[0039] As shown in Figure 5, at the tip side where rough frequency adjustment is performed, the weight film 75 is removed across the entire width until the main surface A0 of the vibrating arm 7 is exposed by irradiating it with a non-thermal processing laser Lf, and in the intermediate region where fine adjustment is performed halfway through, the central part is removed while leaving both ends in the width direction. In the intermediate region where this fine adjustment is performed, as shown in Figure 5(a), as the scanning position of the non-thermal processing laser Lf moves toward the base 8, the scanning width is gradually narrowed, so that part of the inclined portion B is formed into a V-shaped recess. As shown in FIG. 5, the V-shaped recesses are formed symmetrically in the width direction of the vibrating arm 7, thereby preventing the vibration balance from being changed.

[0040] As shown in Figures 5(a) and (b), the inclined portion B of the second embodiment has inclined surfaces B1 facing the longitudinal direction formed on both the left and right (width direction) sides of the longitudinal tip side and in the central portion on the longitudinal base 8 side. On the other hand, in the V-shaped recess, as shown in Figures 5(c) and (d), which show the longitudinal and width cross sections, the inclined portion B is formed with inclined surfaces B2 and B3 that are inclined relative to the longitudinal direction. The inclination angles of the inclined surfaces B2 and B3 which are inclined with respect to the longitudinal direction are gentler than the inclined surface B1 which is inclined in the longitudinal direction. Therefore, according to this embodiment, compared to the first embodiment, the step between the first thickness portion C and the main surface A0 (or the second thickness portion A described later) can be formed with a more gentle slope, thereby making it possible to further stabilize the vibration by the vibrating arm portion 7.

[0041] In the second embodiment described above, the inclined portion B is formed by the inclined surface B1 facing the longitudinal direction and the inclined surfaces B2 and B3 facing in a direction inclined with respect to the longitudinal direction. In contrast, it is also possible to form the inclined surface B only in a direction inclined with respect to the longitudinal direction. In this case, the inclined surface may be formed so as to face the center of both vibrating arms 7a and 7b (see FIG. 6), so as to face outward, or so as to face one of the outward sides (the same direction). Furthermore, the inclined surface of the inclined portion B is V-shaped in plan view, that is, the center of the width direction of the vibrating arm 7 is recessed, but it may be formed in the opposite manner to this, that is, in a convex shape (inverted V shape).

[0042] In addition, the inclined portion B of the second embodiment has been described as having an end portion opposite to the first thick portion C in contact with the main surface A0 of the vibrating arm portion 7. That is, the main surface A0 is exposed by removing the entire thickness direction without forming the second thick portion A except for a part of the thickness of the weight film 75. In contrast, the second thick portion A may be formed in the tip region for coarse adjustment and the intermediate region for fine adjustment. In this case, by forming it in a V shape in a plan view, an inclined surface (B2, B3 portions) inclined to the longitudinal direction is formed between the first thick portion C and the second thick portion A. Furthermore, as explained in FIG. 4, the above (i) to (e) in the first embodiment and various modifications resulting from combinations of these can also be applied to the second embodiment and the modified examples of the second embodiment.

[0043] The shape and formation of the weight film 75 formed on the tip of the piezoelectric vibrating piece in the first and second embodiments and the modified examples have been described above. Next, a piezoelectric vibrating piece formed in this manner and a piezoelectric vibrator housing the piezoelectric vibrating piece will be described. FIG. 6 is an exploded perspective view of a piezoelectric vibrator that houses a piezoelectric vibrating piece. As shown in Figure 6, the piezoelectric vibrator 1 of this embodiment is a ceramic package type surface mount type vibrator that includes a package 2 having an airtight sealed cavity C therein, and a piezoelectric vibrating piece 6 housed in the cavity C. In addition, since the piezoelectric vibrator 1 of this embodiment has a bilaterally symmetrical structure, both symmetrically arranged parts, such as the vibrating arm part 7a and the vibrating arm part 7b, are represented by the same numerals, and in order to distinguish between the two parts, one part is given the distinguishing symbols a and A, and the other part is given the distinguishing symbols b and B. However, the distinguishing symbols will be omitted as appropriate in the explanation, in which case they are taken to refer to each part.

[0044] The piezoelectric vibrating piece 6 is a so-called tuning fork type vibrating piece formed from a piezoelectric material such as quartz, lithium tantalate, or lithium niobate, and vibrates when a predetermined voltage is applied. In this embodiment, a so-called side arm type piezoelectric vibrating piece 6 is taken as an example and described among the piezoelectric vibrating pieces formed using quartz as the piezoelectric material. The piezoelectric vibrating reed 6 has vibrating arms 7a, 7b extending in parallel from a base 8, and supporting arms 9a, 9b extending from the base 8 in the same direction outside the vibrating arms 7a, 7b, and is held within the cavity C by the supporting arms 9a, 9b.

[0045] The pair of vibrating arms 7a, 7b are arranged parallel to each other, with the end on the base 8 side being a fixed end and the tip being a free end that vibrates. The pair of vibrating arms 7a, 7b are provided at their tips with widened portions 71a, 71b that are wider on both sides than the center of the entire length. The widened portions 71a, 71b formed on the vibrating arms 7a, 7b have the function of increasing the weight of the vibrating arms 7a, 7b and the moment of inertia during vibration. This makes it easier for the vibrating arms 7a, 7b to vibrate, and the length of the vibrating arms 7a, 7b can be shortened, resulting in a compact design. Weight films 75 having different thicknesses as described with reference to FIG. 1 are formed on the main surfaces of the widened portions 71a and 71b. In addition, in the piezoelectric vibrating piece 6 of this embodiment, widened portions 71a, 71b are formed in the vibrating arms 7a, 7b, and a weight film 75 with an inclined step is formed in these widened portions 71a, 71b. However, it is also possible to use a piezoelectric vibrating piece that does not have the widened portions 71a, 71b, in which the width of the tip of the vibrating arm 7 is formed to be approximately the same as that of the central portion.

[0046] Grooves 72a, 72b are formed on both main surfaces of the vibrating arms 7a, 7b, extending from the base 8 side to just before the widened portions 71a, 71b. As a result, the cross-sectional shape of the vibrating arms 7a, 7b is H-shaped. A pair of (two systems) of excitation electrodes (not shown) are formed on the outer surfaces (outer peripheral surfaces) of the pair of vibrating arms 7a, 7b, comprising a first system formed on both outer side surfaces of the vibrating arm 7a and in the groove portion 72b of the vibrating arm 7b, and a second system formed on both outer side surfaces of the vibrating arm 7b and in the groove portion 72a of the vibrating arm 7a. Although not shown, a first mount electrode connected to the excitation electrode of the first system is formed from the base 8 to the outer surface (outer peripheral surface) of the support arm 9a, and a second mount electrode connected to the excitation electrode of the second system is formed from the base 8 to the outer surface (outer peripheral surface) of the support arm 9b. The excitation electrode and the mount electrode are laminated films consisting of a first chromium (Cr) layer and a second gold (Au) layer, and are formed by electrode sputtering or the like.

[0047] The package 2 is formed in a roughly rectangular parallelepiped shape and includes a package body 3 and a sealing plate 4 that is joined to the package body 3 and forms a cavity C between the package body 3 and the sealing plate 4. The package body 3 includes a first base substrate 10 and a second base substrate 11 that are bonded together in a stacked state, and a seal ring 12 that is bonded onto the second base substrate 11.

[0048] The upper surface of the first base substrate 10 corresponds to the bottom surface of the cavity C. The second base substrate 11 is placed on the first base substrate 10 and is bonded to the first base substrate 10 by sintering or the like. That is, the second base substrate 11 is integrated with the first base substrate 10. Between the first base substrate 10 and the second base substrate 11, a connection electrode (not shown) is formed in a state where it is sandwiched between both the base substrates 10 and 11.

[0049] In the second base substrate 11, a through portion 11a that constitutes a part of the side wall of the cavity C is formed. Mounting portions 14A and 14B protruding inward are provided on both inner surfaces of the through portion 11a that face each other in the short direction. A pair of electrode pads (electrode portions) 20A, 20B, which are connection electrodes with the piezoelectric vibrating reed 6, are formed on the upper surfaces of the mounting portions 14A, 14B. In addition, a pair of external electrodes 21A, 21B are formed on the lower surface of the first base substrate 10 with a gap therebetween in the longitudinal direction of the package 2. The electrode pads 20A, 20B and the external electrodes 21A, 21B are single-layer films made of a single metal formed by, for example, vapor deposition or sputtering, or laminated films in which different metals are laminated. The electrode pads 20A, 20B and the external electrodes 21A, 21B are each electrically connected to each other via a second through electrode (not shown) formed in the mounting portions 14A, 14B of the second base substrate 11, a connection electrode (not shown) formed between the first base substrate 10 and the second base substrate 11, and a first through electrode (not shown) formed in the first base substrate 10. On the other hand, a conductive adhesive 51 is applied onto the electrode pads 20A and 20B, and these are joined to the mount electrodes of the supporting arms 9a and 9b.

[0050] The seal ring 12 is a conductive frame-shaped member that is slightly smaller than the outer shapes of the first base substrate 10 and the second base substrate 11, and is joined to the upper surface of the second base substrate 11. Specifically, the seal ring 12 is joined to the second base substrate 11 by baking with a brazing material such as silver brazing or a solder material, or by welding to a metal bonding layer formed on the second base substrate 11 (for example, by electrolytic plating, electroless plating, vapor deposition, sputtering, or the like).

[0051] The sealing plate 4 is a conductive substrate overlaid on the seal ring 12, and is hermetically joined to the package body 3 by being bonded to the seal ring 12. The space defined by the sealing plate 4, the seal ring 12, the through portion 11a of the second base substrate 11, and the upper surface of the first base substrate 10 functions as a cavity C that is hermetically sealed.

[0052] The piezoelectric vibrator 1 shown in FIG. 6 is formed through the following steps. (1) Manufacturing of the piezoelectric vibrating piece 6 (a) In the outer shape forming step, quartz crystal is used to form the outer shape of a tuning fork-type piezoelectric vibrating piece having vibrating arms. (b) In the electrode formation process, two systems of excitation electrodes and a mount electrode are formed. (c) Weight Membrane shape In the forming step, a weight film 75 having a thickness of N μm is formed on the main surface on the tip side of the vibrating arm portion 7. This weight film forming step may be performed either before or after the electrode forming step, or simultaneously with the electrode forming step. (d) In the frequency adjustment process, the non-thermal processing laser Lf is directly irradiated onto the weight film 75, and an area and thickness corresponding to the frequency adjustment width are removed to form the second thickness portion A and the inclined portion B. In the frequency adjustment process, rough adjustment is performed to remove the tip side, and fine adjustment is performed to remove the base portion 8 side.

[0053] (2) Manufacturing of Piezoelectric Vibrator 1 (e) In the piezoelectric vibrating piece manufacturing process, the piezoelectric vibrating piece 6 is manufactured by each step of (1). (f) In the mounting step, the manufactured piezoelectric vibrating piece 6 is mounted on the electrode pads 20 of the mounting portion 14 formed on the package body 3 by adhering the supporting arm portions 9 with a conductive adhesive 51 . (g) In the sealing step, the package body 3 on which the piezoelectric vibrating piece 6 is mounted is sealed with the sealing plate 4.

[0054] When manufacturing the piezoelectric vibrator 1, a final frequency adjustment process may be performed between the mounting process and the sealing process. (f-2) In the final frequency adjustment, ion trimming is performed on the weight film 75 of the mounted piezoelectric vibrating reed 6. That is, the frequency of the piezoelectric vibrating piece 6 after mounting is measured, and final adjustment of the frequency is performed by ion trimming the surface of the entire weight film 75 (first thickness portion C, inclined portion B, second thickness portion A) to achieve the desired frequency. In ion trimming, the surface of the weight film 75 is polished (removed thinly) by irradiating unconverged argon ions accelerated to several KV while masking the areas other than the weight film 75, and utilizing the sputtering phenomenon.

[0055] In this embodiment, the weight film 75 formed on the main surface is not melted and removed entirely in the thickness direction, but is irradiated with a non-thermal processing laser Lf to thinly remove a portion in the thickness direction to form the second thickness portion A and the inclined portion B. That is, the weight film 75 formed on the main surface in the (c) weight film forming process has a thinner thickness depending on the region, but the area on the main surface is the same. Therefore, since the area to be polished by ion trimming is large (the area formed at the present location remains the same), it is possible to remove a predetermined weight of the weight film 75 by ion trimming for a short period of time.

[0056] The above describes the side arm type piezoelectric vibrating piece 6 and the configuration of the piezoelectric vibrator 1 using this piezoelectric vibrating piece 6, but it is also possible to form a weight film 75 with an inclined step on other types of piezoelectric vibrating pieces as long as they are tuning fork type. FIG. 7 is an explanatory diagram showing other types of piezoelectric vibrating pieces, in which (a) is a cantilever type piezoelectric vibrating piece 61 and (b) is a center arm type piezoelectric vibrating piece 62. A piezoelectric vibrating piece 61 shown in Fig. 7(a) has vibrating arms 7a and 7b extending parallel to the longitudinal direction from a base 8, and has no supporting arms. On the other hand, a piezoelectric vibrating piece 62 shown in Fig. 7(b) has a supporting arm 9c formed between the vibrating arms 7a and 7b extending parallel to the longitudinal direction from a base 8.

[0057] In both piezoelectric vibrating pieces 61 and 62, grooves 72a and 72b are formed on both main surfaces of a pair of vibrating arms 7a and 7b, similar to the piezoelectric vibrating piece 6 described with reference to FIG. In addition, a first system excitation electrode 92 is formed on both outer side surfaces of the vibrating arm 7a and in the groove portion 72b of the vibrating arm 7b, and a second system excitation electrode 91 is formed on both outer side surfaces of the vibrating arm 7b and in the groove portion 72a of the vibrating arm 7a.

[0058] As shown in Figure 7(a), the cantilever-type piezoelectric vibrating piece 61 has a first mount electrode 92m connected to the excitation electrode 92 of the first system and a second mount electrode 91m connected to the excitation electrode 91 of the second system formed on the base 8. On the other hand, as shown in Figure 7(b), in the center arm type piezoelectric vibrating piece 62, a first mount electrode 92m connected to the excitation electrode 92 of the first system is formed from the base 8 to the tip of the supporting single arm portion 9c, and a second mount electrode 91m connected to the excitation electrode 91 of the second system is formed from the base 8 to the center of the supporting single arm portion 9c.

[0059] Both the piezoelectric vibrating pieces 61 and 62 are housed in the package 2 in the same manner as the piezoelectric vibrating piece 6 described with reference to FIG. 6, thereby forming a piezoelectric vibrator. In this case, the package 2 has mounting portions corresponding to the mounting portions 14A and 14B described in FIG. 6 formed at the position of the base 8 in the case of the piezoelectric vibrating piece 61, and at the position of the supporting arm portion 9c in the case of the piezoelectric vibrating piece 62, and are bonded and fixed to the two systems of electrode pads formed on these mounting portions with a conductive adhesive.

[0060] In the cantilever type piezoelectric vibrating piece 61 of Fig. 7(a), there is no widened portion 71 at the tip of the vibrating arm 7, while in the center arm type piezoelectric vibrating piece 62 of (b), the widened portion 71 is formed at the tip of the vibrating arm 7. In both piezoelectric vibrating pieces 61 and 62, a weight film 75 is formed at the tip of the vibrating arm 7, and the cross section along the longitudinal direction is frequency-adjusted by irradiating the non-thermal processing laser Lf as described in Fig. 1. As a result, the weight film 75 has different thicknesses and inclined surfaces depending on the region, and is formed into a shape with inclined steps. It should be noted that this embodiment can be configured as follows. (1) In configuration 1, a piezoelectric vibrating piece formed in a tuning fork shape from quartz crystal is mounted in a package with an internal mounting portion, and is characterized in that it comprises a base, a pair of vibrating arms extending in parallel from the base, two systems of electrodes formed on the pair of vibrating arms, and a weight film for frequency adjustment having a first thickness portion formed of metal at the tip of the vibrating arms, and a sloped portion continuous with the first thickness portion and having an inclined surface formed on at least one of the base side and tip side, the thickness of which gradually becomes thinner than the first thickness portion. (2) Configuration 2 provides a piezoelectric vibrating reed as described in configuration 1, characterized in that the inclined portion is composed of at least one of an inclined surface facing the longitudinal direction of the vibrating arm portion and an inclined surface facing in a direction inclined with respect to the longitudinal direction. (3) In configuration 3, there is provided a piezoelectric vibrating piece as described in configuration 1 or 2, characterized in that the weight membrane has a second thickness portion formed thinner than the first thickness portion, and the inclined portion is continuous with the first thickness portion on one side and with the second thickness portion on the other side. (4) In configuration 4, there is provided a piezoelectric vibrating piece as described in configuration 1 or 2, characterized in that the inclined portion of the weight film is continuous with the first thickness portion on one side in the longitudinal direction of the vibrating arm, and abuts the main surface of the vibrating arm on the other side. (5) Configuration 5 provides a piezoelectric vibrating piece according to any one of configurations 1 to 4, characterized in that the inclined portion has one or more inclined step portions between the one side and the other side in the longitudinal direction. (6) Configuration 6 provides a piezoelectric vibrating piece according to any one of configurations 1 to 4, characterized in that the length of the inclined portion in the inclined surface direction is equal to or greater than half the spot diameter of the laser light forming the inclined portion. (7) In configuration 7, there is provided a piezoelectric vibrating piece according to any one of configurations 1 to 6, characterized in that the weight film is formed on at least one of the main surfaces of the tip of the vibrating arm portion. (8) In configuration 8, there is provided a piezoelectric vibrating piece according to any one of configurations 1 to 7, characterized in that the inclined portion of the weight film is formed on the tip side. (9) Configuration 9 provides a piezoelectric vibrating piece according to any one of configurations 1 to 8, characterized in that the piezoelectric vibrating piece is a side arm type mounted on the mounting portion by a support arm formed extending from the base to the outside of the vibrating arms, a center arm type mounted on the mounting portion by a single support arm formed extending from the base between the vibrating arms, or a cantilever type in which the base is mounted on the mounting portion. (10) In configuration 10, a piezoelectric vibrator is provided, comprising: a package having a mounting portion on the inside; a piezoelectric vibrating piece described in any one of configurations 1 to 9 mounted on the mounting portion; and an external electrode portion formed from the mounting portion to the outside of the package. (11) In configuration 11, there is provided a method for manufacturing a piezoelectric vibrating reed, comprising: an outer shape forming process for forming an outer shape of a tuning-fork-type piezoelectric vibrating reed having at least a base and a pair of vibrating arms extending in parallel from the base; an electrode forming process for forming two systems of electrodes on the vibrating arms; a weight film forming process for forming a weight film for adjusting the frequency on a main surface on the tip side of the vibrating arms; and a frequency adjusting process for adjusting the frequency by removing the weight film and forming an inclined portion having an inclined surface whose thickness gradually decreases in at least a portion of the weight film. (12) In a twelfth aspect, there is provided the method for producing a piezoelectric vibrating piece according to the eleventh aspect, wherein the frequency adjustment step removes a part of the weight film by a non-thermal process. (13) In configuration 13, there is provided a method for manufacturing a piezoelectric vibrating piece according to configuration 12, characterized in that the frequency adjustment process directly irradiates a non-thermal processing laser having a pulse width such that removal of the weight film is a non-thermal process. (14) In a fourteenth aspect, there is provided the method for manufacturing a piezoelectric vibrating piece according to the thirteenth aspect, wherein the non-thermal processing laser is a picosecond laser or a femtosecond laser having a pulse width of two digits or less. (15) Configuration 15 provides a method for manufacturing a piezoelectric vibrating piece according to any one of configurations 11 to 14, characterized in that the frequency adjustment process includes performing coarse adjustment in a first region on the tip side of the vibrating arm, and then performing fine adjustment in a second region on the base side of the first region. (16) Configuration 16 provides a method for manufacturing a piezoelectric vibrator, comprising the steps of manufacturing a piezoelectric vibrating piece by any one of the steps of configurations 11 to 15, a mounting step of mounting the piezoelectric vibrating piece to a mounting portion formed in a package, and a sealing step of sealing the package. (17) Configuration 17 provides a method for manufacturing a piezoelectric vibrator according to configuration 16, characterized in that a final frequency adjustment process is performed between the mounting process and the sealing process, in which ion trimming is performed on the weight film of the mounted piezoelectric vibrating piece. (21) In configuration 21, there is provided a piezoelectric vibrating reed formed in a tuning fork shape from quartz crystal and mounted in a package having an internal mounting portion, the piezoelectric vibrating reed comprising: a base; a pair of vibrating arms extending in parallel from the base; two systems of electrodes formed on the pair of vibrating arms; and a weight film for adjusting a frequency having a first thickness portion formed of metal at the tip of the vibrating arms; and an inclined portion continuous with the first thickness portion and having an inclined surface formed on at least one of the base side and the tip side and having a thickness that gradually becomes thinner than that of the first thickness portion, the inclined portion being composed of a first inclined surface formed of a plurality of step portions and facing the longitudinal direction of the vibrating arms, and a second inclined surface facing a direction inclined with respect to the longitudinal direction and width direction of the vibrating arms, the second inclined surface being formed into a slope that is gentler than that of the first inclined surface, and the step portion having an upper end in the thickness direction formed into a convex curved surface and a lower end formed into a concave curved surface. (22) Configuration 22 provides the piezoelectric vibrating piece according to configuration 21, characterized in that the second inclined surfaces are formed symmetrically on both sides of the first inclined surface in the width direction of the vibrating arm portion. (23) Configuration 23 provides the piezoelectric vibrating piece according to configuration 22, characterized in that the inclined portion is formed into a concave shape by the first inclined surface and second inclined surfaces formed on both sides. (24) In configuration 24, there is provided a piezoelectric vibrating piece according to any one of configurations 21 to 23, characterized in that the weight film is formed on at least one of the main surfaces of the tip of the vibrating arm portion. (25) In configuration 25, there is provided a piezoelectric vibrating piece according to any one of configurations 21 to 24, characterized in that the inclined portion of the weight film is formed on the tip side. (26) Configuration 26 provides a piezoelectric vibrating piece according to any one of configurations 21 to 25, characterized in that the piezoelectric vibrating piece is a side arm type mounted on the mounting portion by a support arm formed extending from the base to the outside of the vibrating arms, a center arm type mounted on the mounting portion by a single support arm formed extending from the base between the vibrating arms, or a cantilever type in which the base is mounted on the mounting portion. (27) Configuration 27 provides a piezoelectric vibrator comprising: a package having a mounting portion on the inside; a piezoelectric vibrating piece described in any one of configurations 21 to 26 mounted on the mounting portion; and an external electrode portion formed from the mounting portion to the outside of the package. [Explanation of symbols]

[0061] 1 Piezoelectric vibrator 2 Package 3 Package body 4 Sealing plate 6 Piezoelectric vibrating piece 7, 7a, 7b Vibrating arm 8 Base 9, 9a, 9b Support arm 9c Support single arm 10 First base substrate 11 Second base substrate 14, 14A, 14B mounting section 20, 20A, 20B Electrode pads 21, 21A, 21B external electrode 51 Conductive adhesive 61, 62, Piezoelectric vibrating piece 72 Groove 75 Weight Membrane 91, 92 Excitation electrode 91m, 92m Mount electrode C Cavity

Claims

1. A piezoelectric vibrating piece formed in a tuning fork shape using quartz crystal, the tuning fork being mounted in a package having a mounting portion on the inside, A base and A pair of vibrating arms extending from the base portion side by side; Two systems of electrodes formed on the pair of vibrating arms; A weight film for adjusting a frequency formed of a metal at a tip of the vibrating arm is provided. The weight membrane is A first thickness portion; a first inclined surface formed on at least one of the base side and the tip side of the first thickness portion, the first inclined surface being flat and having a thickness that is gradually thinner than that of the first thickness portion; a first curved surface that is curved in a convex shape and that continuously connects the first thickness portion and the first inclined surface; A piezoelectric vibrating piece comprising:

2. The first inclined surface is formed so that an end portion opposite to the first thickness portion abuts against a quartz crystal surface of the vibrating arm portion. The piezoelectric vibrating piece according to claim 1 .

3. The weight membrane has a second thickness portion formed thinner than the first thickness portion, The first inclined surface is continuous with the second thickness portion on the side opposite to the first thickness portion. The piezoelectric vibrating piece according to claim 1 .

4. A second curved surface curved in a concave shape is formed at the connection portion between the first inclined surface and the second thickness portion. The piezoelectric vibrating piece according to claim 3 .

5. The weight membrane is a planar second inclined surface that faces the first inclined surface and is formed on a side of the second thickness portion opposite to the first inclined surface; a third thickness portion formed on the second inclined surface opposite to the second thickness portion, the third thickness portion being thinner than the first thickness portion and thicker than the second thickness portion; 5. The piezoelectric vibrating piece according to claim 3, further comprising:

6. The weight film is formed on both sides of the vibrating arm portion, and the first thickness portion, the first inclined surface, and the first curved surface are formed on at least one of the sides.

6. The piezoelectric vibrating piece according to claim 1, wherein the piezoelectric vibrating piece is a piezoelectric vibrating piece having a thickness of 100 nm or less.

7. a side arm type mounted on the mounting portion by a support arm portion formed by extending from the base to the outside of the vibrating arm portion; A center arm type in which a single support arm portion is formed extending from the base between the vibrating arms and mounted on the mounting portion, or a cantilever type in which the base is mounted on the mounting portion; 7. The piezoelectric vibrating piece according to claim 1, wherein:

8. A package having a mounting portion therein; The piezoelectric vibrating piece according to any one of claims 1 to 7, which is mounted on the mounting portion; an external electrode portion formed from the mounting portion to the outside of the package; A piezoelectric vibrator comprising:

Images