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 crystal. [Background technology]

[0002] For example, in electronic devices such as mobile phones and personal digital assistants, piezoelectric vibrators using piezoelectric vibrating pieces formed in a tuning fork shape are used as devices used as time sources, timing sources for control signals, reference signal sources, etc. In such tuning fork-type piezoelectric vibrating reeds, 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 reed mounted on a package is oscillated, and while the frequency is 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 from 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 creates 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 it is not possible to further improve the frequency adjustment accuracy. In particular, in the case of small piezoelectric vibrating pieces, such as those 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 and 752 are generated on the main surface and side surfaces around the weight film 750 that remains 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 roughly the same, i.e., 20 μm, which is large and causes imbalance between the left and right sides of the longitudinal center line P. In the example shown in Figure 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 and 752 are generated not only on the left and right sides 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 disrupted, resulting in 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 removed by vibration. teeth If the debris falls due to vibration, it could cause imbalance between the left and right vibrating arms, and the change in weight could affect the frequency. Generally, the smaller the piezoelectric vibrating reed, the thicker the weight film 750 must be to ensure the weight, which makes it more likely that debris 751 will be generated when the weight film 750 is melted and removed with the laser Ln. For this reason, the smaller the piezoelectric vibrating reed, 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] Japanese Patent Application Laid-Open No. 2003-133879 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to prevent 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 of quartz in a tuning fork shape and mounted in a package with a mounting portion inside, the piezoelectric vibrating piece comprising: a base portion; a pair of vibrating arms extending side by side from the base portion; two systems of electrodes formed on the pair of vibrating arms; and a weight film for frequency adjustment formed of metal on the tip portion of the vibrating arms, the weight film comprising: a first thickness portion; a first inclined surface formed on at least one of the base side and tip side of the first thickness portion, the first inclined surface having a thickness that is gradually thinner than 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. a second thickness portion formed thinner than the first thickness portion; a second inclined surface facing the first inclined surface and formed on the second thickness portion on the side opposite to the first inclined surface; and a third thickness portion formed on the second inclined surface on the side opposite to the second thickness portion, the third thickness portion being thinner than the first thickness portion and thicker than the second thickness portion, and the first inclined surface is continuous with the second thickness portion on the side opposite to the first thickness portion, The present invention provides a piezoelectric vibrating piece characterized by the above features. (2) Claim 2 In the invention described in the item (1), a second curved surface curved in a concave shape is formed at a connection portion between the first inclined surface and the second thickness portion. 1 The present invention provides a piezoelectric vibrating piece according to the present invention. (3) Claim 3 In the invention described in the item (1), 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 surface of the weight film. 1 or claim 2 The present invention provides a piezoelectric vibrating piece according to any one of claims 1 to 4. (4) Claim 4 In the invention described in claim 1, the piezoelectric element is a side arm type mounted on the mounting part by a support arm formed extending from the base to the outside of the vibrating arm, a center arm type mounted on the mounting part by a single support arm formed extending from the base between the vibrating arms, or a cantilever type mounted on the mounting part by the base. 3 The present invention provides a piezoelectric vibrating piece according to any one of claims 1 to 4. (5)Claim 5 The invention described in claim 1 includes a package having a mounting portion inside, and a semiconductor device mounted on the mounting portion. 4 The present invention provides a piezoelectric vibrator comprising: a piezoelectric vibrating piece according to any one of claims 1 to 4; and an external electrode portion formed from the mounting portion to the outside of the package. [Effects of the Invention]

[0009] According to the present invention, the weight film formed at the tip of the vibrating arm portion includes a first thickness portion, a first inclined surface whose thickness is 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. a second thickness portion formed thinner than the first thickness portion; a second inclined surface facing the first inclined surface and formed on the second thickness portion on the side opposite to the first inclined surface; and a third thickness portion formed on the second inclined surface on the side opposite to the second thickness portion, the third thickness portion being thinner than the first thickness portion and thicker than the second thickness portion, and the first inclined surface is continuous with the second thickness portion on the side opposite to the first thickness portion. This reduces abrupt thickness changes, making it possible to further stabilize vibration. [Brief explanation of the drawings]

[0010] [Figure 1] 10A and 10B are explanatory diagrams showing the shape of weight films formed at the tips of vibrating arms of a piezoelectric vibrating piece. [Figure 2] 10 is an explanatory diagram of a method for removing a weight film using a non-thermal processing laser Lf. FIG. [Figure 3] 10 is an explanatory diagram showing a state in which a part of the weight film has been removed by a non-thermal processing laser Lf. FIG. [Figure 4] 10A and 10B are explanatory diagrams showing modified shapes of weight films formed at the tips of the vibrating arms. [Figure 5] FIG. 10 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 that houses a piezoelectric vibrating piece. [Figure 7] 10A and 10B are explanatory diagrams of other shapes of the piezoelectric vibrating reed. [Figure 8] 10 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 INVENTION

[0011] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 7. (1) Outline of the embodiment In the piezoelectric vibrating piece of the present embodiment, instead of melting and removing the entire predetermined region (the entire thickness) of the weight film 75 provided at the tip of the vibrating arm portion 7 (7a, 7b), it is removed by non-thermal processing. When removing the weight film 75 by non-thermal processing, the removed end portion (the end portion in the longitudinal direction of the vibrating arm portion 7) is formed so as to gradually become thinner along the longitudinal direction. That is, an inclined portion B is formed that is continuous with the original thickness portion (the first thickness portion C) and gradually becomes thinner. The end portion 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 so as 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 it. Here, the non-thermal processing laser Lf uses a laser with 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.

[0012] By this non-thermal processing laser Lf, with respect to the thickness N μm of the weight film 75 before processing, the upper surface side is removed leaving a thickness of n μm (n < N) 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 N μm), 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 scans and / or the pulse width of scanning the region with the non-thermal processing laser Lf. 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 it goes 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, the presence of steep steps is reduced by forming the inclined portion B that is continuous with the first thickness portion C in the frequency adjustment weight film 75. In other words, by making the cross-sectional shape of the weight film 75 into a shape with an inclined step, it is possible to further stabilize the vibration. Furthermore, by forming the second thickness portion A, highly accurate frequency adjustment becomes possible, and the frequency accuracy of the piezoelectric vibrating reed 6 can be increased. In addition, since non-thermal processing is performed using the non-thermal processing laser Lf, it is possible to eliminate the generation of debris due to melting and removal. This allows frequency adjustment to be performed with a balance not only between each vibrating arm 7 but also between both vibrating arms 7a and 7b, thereby suppressing 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 removed by vibration.

[0014] (2) Details of the First Embodiment The first embodiment is a tuning-fork type piezoelectric vibrating piece 6 using quartz crystal, the details of which will be described later in Figure 6. A pair of vibrating arms 7 (7a, 7b) extend from a base 8, and support arms 9 (9a, 9b) are formed to support the piezoelectric vibrating piece 6 within the package 2. Grooves 72 of a certain width are formed in the main surfaces (rear surfaces) of the pair of vibrating arms 7 in the longitudinal direction. Two different systems of excitation electrodes 91 and 92 that function as first and second excitation electrodes are formed on the side surfaces and main surfaces that form the outer peripheral surfaces of the vibrating arms 7, and within the grooves 72. It is possible not to form the grooves 72 in the vibrating arm 7, including in each of the modified examples described later, but in the case where they 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 end of the vibrating arm 7 in the longitudinal direction (on the tip side of the groove 72).

[0015] FIG. 1 shows the tip shape of the vibrating arm portion 7 in the piezoelectric vibrating piece of the present embodiment. In FIGS. 1 to 5, only one tip portion of one pair of vibrating arm portions 7 is shown. In each figure, the shaded portion represents the weight film 75 except in FIG. 5, and represents 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 N μm by various methods such as vacuum evaporation. In the present embodiment, the weight film 75 is formed to a predetermined thickness N μm = 3 μm, but the thickness N μm is appropriately selected according to various conditions such as the size of the piezoelectric vibrating piece to be manufactured, various types such as the center arm type described later, and whether the tip of the vibrating arm portion 7 expands 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, but since the non-thermal processing laser Lf is directly irradiated on the weight film 75, it can also be formed 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 of the drawing, see FIG. 6). As shown in FIG. 1(b), the first thickness portion C is a region where the film thickness remains the initial N μm without being processed by the non-thermal processing laser Lf. 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 parallel to the main surface of the vibrating arm portion 7 and remains with 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 continuous with the first thick portion C on the base 8 side and with the second thick portion A on the tip side, thereby forming an inclined surface whose thickness gradually decreases from the base 8 side toward the tip side. This inclined portion B is a portion for adjusting the frequency by removing a portion of the weight film 75, and for stabilizing the vibration of 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 of greater than 0 degrees and less 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 thickness portion A from the thickness N of the first thickness 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 longitudinal length of the inclined portion B may be narrower than 1 / 2 of the spot diameter p1 of the laser light from 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 this inclined portion B is preferably selected to have a constant width and is a predetermined 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 thickness portion A and the first thickness portion C vary depending on the frequency adjustment range. That is, the length of the second thickness 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, which is determined according to the frequency adjustment range. The length of the first thickness portion C is the length after the second thickness portion A and the inclined portion B have been removed.

[0020] Piezoelectric vibrators are formed in various sizes, but the effect of this embodiment is particularly pronounced when the piezoelectric vibrator housing the piezoelectric vibrating piece is small, such as 2.0 mm x 1.2 mm, 1.6 mm x 1.0 mm, or 1.2 mm x 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 with a size of 1.6 mm × 1.0 mm, the piezoelectric vibrating piece is formed with a approximate length of 1 mm, width of 0.5 mm, and thickness of 0.1 m. On the other 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 required frequency adjustment amount for each region.

[0021] For the tuning fork-shaped 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 with a thickness of n2 μm (n2 < N) and an inclined portion may be formed. Alternatively, coarse adjustment of the frequency may be performed 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 may 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, whereby the steep step can be further reduced. Details of various modifications to the embodiment shown in Fig. 1 will be described later.

[0022] Next, a method for processing 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. 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 at the tip of the vibrating arm 7. The weight film 75 of the present embodiment shown in Fig. 2 is formed on one main surface of the vibrating arm 7, but it may be formed on both surfaces or on the entire periphery including the side surfaces. This weight film 75 is turned upward, and as shown in Figure 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 length direction at a movement pitch p2 (e.g., p2 = p1 / 2 = 5 μm) to remove a predetermined area of ​​the weight film 75. In FIG. 2(a), the circle at the tip of the weight film 75 represents the spot diameter p1 of the non-thermal processing laser Lf, and shows the state in which it is moving in the width direction at a movement pitch p2 so that part of the spot of p1 overlaps. Then, a predetermined area of ​​the weight film 75 is removed by moving in the length direction while moving in the width direction at the movement pitch p2.

[0023] In this trimming process, a non-thermal processing laser Lf is scanned in the region A where the second thickness portion A is to be formed, and a thickness of (Nn) μm is removed from the weight film 75 with a thickness of N μm, thereby adjusting the frequency. During this process, the frequency is measured to measure the deviation from the target frequency, and an area (weight) is removed according to the deviation, thereby gradually approaching the target frequency. In this embodiment, a weight is removed from the region A taking into account the weight of the inclined portion B, which will 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 addressed by widening region 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 portion 7, and a portion of the front side of the completely removed portion is removed to form second thickness portion A and 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, an inclined portion B having an inclined surface is formed between the second thick portion A and the first thick portion C, as shown in FIG. 2(c). FIG. 2(d) is an enlarged view showing the state in which the inclined portion B is formed. As shown in Figure 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 thickness portion C and the second thickness 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. Re do.

[0025] In Figure 2(d), the number in parentheses after the non-thermal processing laser Lf indicates the number of times it makes a round trip 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 along each line to form the second thickness portion A. After that, the non-thermal processing laser Lf(2) is scanned two times along a line moved by a predetermined movement pitch p3, and the non-thermal processing laser Lf(1) is scanned one time along a line moved by a further movement pitch p3. 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, slight curved inclined surfaces on both the upper and lower sides of each step further suppress abrupt thickness changes due to small steps. For example, when processing with the non-thermal processing laser Lf, as shown in the cross section of Figure 2(d), the processing edge 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 edge and concavely curved on the lower side (toward the vibrating arm 7). Part of the inclined portion B is formed by using these upper and lower curved surfaces. However, in FIG. 2(d), the inclined surface outside the spot diameter is exaggerated for conceptual explanation.

[0027] In the example shown in Fig. 2(d), the number of longitudinal movements (number of movements at 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 tilt 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 tilt angle θ to be larger.

[0028] FIG. 3(a) shows a side cross section and FIG. 3(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. With conventional lasers Ln with pulse widths of nanoseconds to picoseconds (three digits), the entire weight film in the irradiated area is melted and removed by heat, which generates debris at the boundary of the irradiated area, as shown in Figure 8. This makes it difficult to adjust the frequency of the smaller piezoelectric vibrating reed, and the debris can cause imbalance between the vibrating arms, potentially 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 explode into atoms, molecules, and plasma states (ablation), and remove 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 portion A and the inclined portion B. As a result, it is possible to perform high-precision frequency adjustment even for a more miniaturized piezoelectric vibrating piece.

[0029] Furthermore, as shown in Figure 3(b), since no debris is generated at the boundary 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 relative to a virtual 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. As described above, according to this embodiment, it is possible to prevent the generation of debris, and also to achieve balance between the left and right sides of 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 contrast to this, the following modifications (a) to (e) and various other modifications by combining 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 / base 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 (2) weight film 75 is formed so that there are three or more different thicknesses of the portion 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 the weight membrane 75 according to a modified example 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, in which the second thickness portion A formed on the tip side of the weight film 75 shown in Fig. 1 is completely removed. 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 times (four times 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 (A) 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, forming a second thickness portion A on the base 8 side, and then forming an inclined portion B facing the base 8 side. 2, including all of the modified examples, the 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 the case where the above-mentioned modifications (c) and (a) are adopted. In the example of Figure 4(c), second thickness portions A are formed in two locations on both 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. 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, the second thickness portion A and inclined portion B1 may be formed in this order on the tip side, and then the position and movement 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 thickness portion A on the tip side and the second thickness portion A on the base 8 side.

[0034] FIG. 4(d) shows the case where the above-mentioned modifications (c) and (a) are adopted. Figure 4(d) shows a modified example in which, unlike the modified example (c), 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 first thick portions C are formed in two locations on the outside (the tip side and the base 8 side).

[0035] FIG. 4(e) shows the case where the above-mentioned modifications (c), (a), and (d) are adopted. In FIG. 4(e), as in the modified example of (c), an inclined portion B1 and an inclined portion B2 are formed on the tip side and the base 8 side of the first thickness portion C formed in the center, but the difference from (c) is that a second thickness portion A2 is formed on the base 8 side, and a second thickness portion A1 (third thickness portion) that is thicker than the second thickness 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 thickness portion C, an inclined portion B1, a second thickness portion A1, an inclined portion B2, and a second thickness 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 locations in the same direction (toward the base portion 8). In addition, the order of forming the first thickness portion C to the second thickness portion A2 shown in Figure 4(f) may be reversed, and the second thickness portion A2, the inclined portion B2, the second thickness portion A1, the inclined portion B1, and the first thickness 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 thickness portion C1, an inclined portion B1, and a second thickness 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 thickness portion C2, an inclined portion B2, and a second thickness portion A2 are formed on the other main surface. The thickness of the second thick portion A1 on one side and the thickness of the second thick portion A2 on the other side are the same, but one may be formed to be thicker than the other. Furthermore, the order of forming the second thickness portion A, the inclined portion B, and the first thickness portion C may be reversed, so that the first thickness 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, the case where the inclined surface of the inclined portion B faces the longitudinal direction of the vibrating arm portion 7 (see FIG. 2) has been described. 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 solid.

[0039] As shown in Figure 5, at the tip end 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 middle region where fine adjustment is performed halfway through, the center 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, and 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 tip side in the longitudinal direction and in the central part on the base portion 8 side in the longitudinal direction. 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 oriented in a direction inclined relative to the longitudinal direction. The inclination angles of the inclined surfaces B2 and B3 that are inclined relative to the longitudinal direction are gentler than the inclined surface B1 that 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 gently sloping surface, 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 relative to the longitudinal direction. However, it is also possible to form the inclined surface B only in a direction inclined relative 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 has a V-shape in plan view, that is, a shape in which the center in the width direction of the vibrating arm portion 7 is recessed, but it may be formed in the opposite way to a convex shape (inverted V shape).

[0042] In the second embodiment, the inclined portion B has been described as having an end portion opposite to the first thickness portion C that abuts against the main surface A0 of the vibrating arm portion 7. That is, the main surface A0 is exposed by removing the entire thickness of the weight film 75 without forming the second thickness portion A, leaving only a portion of the thickness of the weight film 75. Alternatively, the second thickness portion A may be formed in the tip region for coarse adjustment and the intermediate region for fine adjustment. In this case, by forming the second thickness portion A in a V-shape in plan view, an inclined surface (portions B2 and B3) inclined relative to the longitudinal direction is formed between the first thickness portion C and the second thickness 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 reed 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 that houses 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 vibrator that includes a package 2 having an airtightly sealed cavity C inside, and a piezoelectric vibrating piece 6 housed in the cavity C. Since the piezoelectric vibrator 1 of this embodiment has a bilaterally symmetrical structure, both symmetrically arranged parts, such as vibrating arm part 7a and vibrating arm part 7b, are represented by the same numerals, and in order to distinguish between the two parts, one will be given the distinguishing symbols a and A, and the other will be given the distinguishing symbols b and B. However, the distinguishing symbols will be omitted as appropriate in the explanation, in which case they will 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 will be described as an example of a piezoelectric vibrating piece formed using quartz as the piezoelectric material. The piezoelectric vibrating piece 6 has vibrating arms 7a, 7b extending parallel to the base 8, and support 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 support 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 end being a free end that vibrates. The pair of vibrating arms 7a, 7b are provided at their tip ends with widened portions 71a, 71b that are wider on both sides than the center of their overall 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 the vibrating arms 7a, 7b more easily vibrate, allowing the length of the vibrating arms 7a, 7b to be shortened, resulting in a more compact design. The 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, the piezoelectric vibrating piece 6 of this embodiment has widened portions 71a and 71b formed on the vibrating arm portions 7a and 7b, and a weight film 75 with an inclined step is formed on these widened portions 71a and 71b, but it is also possible to use a piezoelectric vibrating piece that does not have the widened portions 71a and 71b, in which the width of the tip of the vibrating arm portion 7 is formed to be approximately the same as the width of the central portion.

[0046] Grooves 72a and 72b are formed on both main surfaces of the vibrating arms 7a and 7b, extending from the base 8 side to just before the widened portions 71a and 71b. As a result, the cross-sectional shape of the vibrating arms 7a and 7b is H-shaped. A pair of (two systems) excitation electrodes (not shown) are formed on the outer surfaces (outer peripheral surfaces) of the pair of vibrating arms 7a, 7b, consisting of 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 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 itself and the package body 3. 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 sandwiched between both base substrates 10 and 11.

[0049] The second base substrate 11 has a through portion 11a that constitutes a part of the side wall of the cavity C formed therein. Mounting portions 14A and 14B that protrude inward are provided on the inner surfaces of both sides 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 at an interval in the longitudinal direction of the package 2. The electrode pads 20A, 20B and the external electrodes 21A, 21B are either 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 electrically connected to each other via second through electrodes (not shown) formed in the mounting portions 14A, 14B of the second base substrate 11, connection electrodes (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 they are joined to the mount electrodes of the support 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 joining 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 placed 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 hermetically sealed cavity C.

[0052] The piezoelectric vibrator 1 shown in FIG. 6 is formed by the following steps. (1) Manufacturing of the piezoelectric vibrating piece 6 (a) In the outer shape forming step, the outer shape of a tuning fork-type piezoelectric vibrating piece having vibrating arms is formed using quartz crystal. (b) In the electrode formation process, two systems of excitation electrodes and mount electrodes 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 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, coarse 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 by adhering the supporting arm portions 9 to the electrode pads 20 of the mounting portion 14 formed on the package body 3 with a conductive adhesive 51 . In the sealing step (g), 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 step may be performed between the mounting step and the sealing step. (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 it with 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, thereby forming 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 step is thinner depending on the region, but the area on the main surface is the same. Therefore, since the area to be polished by ion rimming is large (the area formed at the time remains the same), it is possible to remove a predetermined weight of the weight film 75 by ion rimming for a short time.

[0056] The above describes the configuration of the side arm type piezoelectric vibrating piece 6 and 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. 7A and 7B are explanatory diagrams showing other types of piezoelectric vibrating reeds, in which (a) is a cantilever type piezoelectric vibrating reed 61 and (b) is a center arm type piezoelectric vibrating reed 62. 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, the piezoelectric vibrating reed 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 the base 8.

[0057] In both piezoelectric vibrating reeds 61 and 62, grooves 72a and 72b are formed on both main surfaces of the pair of vibrating arms 7a and 7b, similar to the piezoelectric vibrating reed 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 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 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 support 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 support single arm portion 9c.

[0059] The piezoelectric vibrating pieces 61 and 62 are both housed in the package 2, similar to the piezoelectric vibrating piece 6 described with reference to FIG. 6, to form a piezoelectric vibrator. In this case, the package 2 has mounting portions corresponding to the mounting portions 14A and 14B described in Figure 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 these are bonded and fixed to the two systems of electrode pads formed on these mounting portions with a conductive adhesive.

[0060] 7(a), the cantilever-type piezoelectric vibrating piece 61 does not have an enlarged portion 71 at the tip of the vibrating arm 7, while the center-arm-type piezoelectric vibrating piece 62 in (b) has an enlarged portion 71 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 it with a 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, forming a shape with inclined steps. This embodiment can be configured as follows. (1) In configuration 1, a piezoelectric vibrating piece is provided that is formed in a tuning fork shape from quartz and is mounted in a package with a mounting portion inside, and is characterized by comprising: a base, a pair of vibrating arms extending side by side from the base, two systems of electrodes formed on the pair of vibrating arms, and a weight film for frequency adjustment that is formed of a metal at the tip of the vibrating arms and has a first thickness portion and an inclined portion that is continuous with the first thickness portion and has an inclined surface formed on at least one of the base side and the tip side, and whose thickness is gradually thinner than that of the first thickness portion. (2) In configuration 2, there is provided a piezoelectric vibrating piece according to configuration 1, characterized in that the inclined portion is composed of at least one inclined surface facing the longitudinal direction of the vibrating arm portion and one inclined surface facing in a direction inclined relative to the longitudinal direction. (3) In configuration 3, there is provided a piezoelectric vibrating piece according to configuration 1 or 2, characterized in that the weight film 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 according to 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 portion, and abuts against the main surface of the vibrating arm portion on the other side. (5) In configuration 5, there is provided 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) In configuration 6, there is provided a piezoelectric vibrating piece according to any one of configurations 1 to 4, characterized in that the length of the inclined portion in the direction of the inclined surface 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 main surface 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 arm, a center arm type mounted on the mounting portion by a 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, characterized by having a package having a mounting portion 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, a method for manufacturing a piezoelectric vibrating piece is provided, which includes an outer shape forming process for forming the outer shape of a tuning fork-type piezoelectric vibrating piece having at least a base and a pair of vibrating arms extending side by side 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 frequency adjustment on the 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 thereof. (12) In a twelfth aspect, there is provided the method for manufacturing a piezoelectric vibrating piece according to the eleventh aspect, wherein the frequency adjusting step removes a part of the weight film by non-thermal processing. (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 non-thermal processing. (14) In a configuration 14, there is provided the method for manufacturing a piezoelectric vibrating piece according to the configuration 13, characterized in that the non-thermal processing laser is a picosecond laser or a femtosecond laser having a pulse width of two digits or less. (15) In configuration 15, there is provided a method for manufacturing a piezoelectric vibrating piece according to any one of configurations 11 to 14, characterized in that the frequency adjustment process involves performing a coarse adjustment in a first region on the tip side of the vibrating arm, and then performing a fine adjustment in a second region on the base side of the first region. (16) In configuration 16, a method for manufacturing a piezoelectric vibrator is provided, characterized by including a step of manufacturing a piezoelectric vibrating piece by each step of any one 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) In configuration 17, there is provided 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, a piezoelectric vibrating piece is provided that is formed in a tuning fork shape from quartz and is mounted in a package with a mounting portion inside, and that includes: a base; a pair of vibrating arms extending side by side from the base; two systems of electrodes formed on the pair of vibrating arms; and a weight film for frequency adjustment that is formed of metal at the tip of the vibrating arms and has a first thickness portion and an inclined portion that is continuous with the first thickness portion and has an inclined surface formed on at least one of the base side and the tip side, and whose thickness is gradually thinner than that of the first thickness portion, wherein the inclined portion is formed of a first inclined surface facing the longitudinal direction of the vibrating arms and a second inclined surface facing in a direction inclined with respect to the longitudinal direction and width direction of the vibrating arms, and the second inclined surface is formed into a slope that is gentler than the first inclined surface, and the step portion has an upper end in the thickness direction formed into a convex curved surface and a lower end formed into a concave curved surface. (22) In configuration 22, there is provided a piezoelectric vibrating piece according to configuration 21, characterized in that the second inclined surfaces are formed symmetrically on both sides of the first inclined surfaces in the width direction of the vibrating arm portion. (23) In configuration 23, there is provided a 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 main surface 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) In configuration 26, there is provided 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 arm, 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) In configuration 27, a piezoelectric vibrator is provided, characterized by having a package having a mounting portion 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 packages 3 Package body 4 Sealing plate 6 Piezoelectric vibrating strip 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 Mounted electrodes C cavity

Claims

1. 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, A base and a pair of vibrating arms extending side by side from the base; Two systems of electrodes formed on the pair of vibrating arms; a weight film for adjusting a frequency formed of metal at the tip of the vibrating arm, 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 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 continuously connects the first thickness portion and the first inclined surface; a second thickness portion formed thinner than the first thickness portion; a second inclined surface that faces the first inclined surface and is formed on the second thickness portion on the opposite side 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, The first inclined surface is continuous with the second thickness portion on the side opposite to the first thickness portion side. A piezoelectric vibrating piece characterized by:

2. 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 thickness portion; The piezoelectric vibrating piece according to claim 1 .

3. 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 surface of the weight film; 3. The piezoelectric vibrating piece according to claim 1, wherein the piezoelectric vibrating piece is made of a material having a thickness of 1000 nm or less.

4. 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 formed extending from the base between the vibrating arms is mounted on the mounting portion, or a cantilever type in which the base is mounted on the mounting portion; 4. The piezoelectric vibrating piece according to claim 1, wherein:

5. a package having a mounting portion therein; The piezoelectric vibrating piece according to any one of claims 1 to 4, 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:

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