Piezoelectric vibrating piece, piezoelectric vibrator, and method for manufacturing piezoelectric vibrating piece and piezoelectric vibrator

Abstract

The purpose of the present invention is to suppress vibration from becoming unstable due to the followability of vibration (amplitude). The piezoelectric vibrating piece is removed by non-thermal working instead of melting and removing the whole (total thickness) of a predetermined region of a weight film (75) provided at the tip of a vibrating arm section (7). When the counterweight film (75) is removed by non-thermal processing, the inclined portion (B) is formed so as to be gradually thinned in the longitudinal direction. An end portion of the inclined portion (B) on the opposite side from the first thickness portion (C) is continuous with a second thickness portion (A) removed to be thinner than the first thickness portion (C) by non-thermal processing. The weight film (75) is not removed by melting, but is removed by non-thermal working by directly irradiating the weight film (75) with a non-thermal working laser (Lf). Here, the non-hot working laser light (Lf) uses a laser light having a pulse width of picosecond (2 bits or less) to femtosecond, such as a femtosecond laser light, which enables non-hot working of the weight film (75).

Description

Technical Field

[0001] The present invention relates to a piezoelectric vibrating piece, a piezoelectric vibrator, a method for manufacturing a piezoelectric vibrating piece, and a method for manufacturing a piezoelectric vibrator, and more particularly, relates to a technology using tuning fork-type quartz. Background Art

[0002] For example, in electronic devices such as mobile phones and portable information terminals, piezoelectric vibrators using tuning-fork-shaped piezoelectric vibrating pieces are used as time sources, timing sources such as control signals, and reference signal sources.

[0003] In such tuning-fork-type piezoelectric resonators, a metal weight film is formed at the tip of the resonating arm, and frequency adjustment is achieved by trimming this film (e.g., Patent Document 1). Specifically, the piezoelectric resonator, mounted in a package, is oscillated, the frequency is measured, and simultaneously, laser light with a pulse width of approximately nanoseconds is irradiated to melt and remove the weight film, thereby trimming and reducing its mass, thereby achieving frequency adjustment (Patent Document 1).

[0004] When trimming with laser light, the melted weight film is placed face downward, and the weight film removed by melting by irradiating the piezoelectric vibrating piece with laser light from the upper surface side (opposite side to the weight film) is received by a recessed portion provided on the bottom surface of the package.

[0005] Figure 8 This is a diagram showing the state of the tip of the vibrating arm portion after the conventional weight film is melted and removed by laser.

[0006] like Figure 8 As shown, in the previous trimming, since the entire counterweight film in the area irradiated with laser is removed, a steep step difference is generated between the counterweight film part that is not removed and the removed part, resulting in a problem of poor tracking of vibration (amplitude) and unstable vibration.

[0007] Furthermore, in conventional frequency adjustment using laser light, the entire weight film 750 in the region irradiated with the laser light Ln is melted and removed, and therefore the frequency adjustment accuracy cannot be further improved.

[0008] In particular, in the case of a small piezoelectric vibrating piece of 3 mm×2 mm or less, since the area of ​​the weight film to be trimmed becomes smaller, finer and more accurate trimming is required for frequency adjustment.

[0009] In addition, in the previous frequency adjustment, such as Figure 8 As shown, since the weight film 750 is melted and removed by the laser light Ln, 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.

[0010] For example, if the spot diameter of the laser light Ln is 20 μm, the width w1 of the debris generated is substantially the same as the deviation width w1 = 20 μm, which is large, thus causing the left-right balance with respect to the center line P in the longitudinal direction to be disrupted. Figure 8 In the example shown in (b), the amount of debris generated on the left side relative to the center line P in the longitudinal direction is greater than that on the right side.

[0011] The debris 751 and 752 is generated not only to the left and right of the center line P of the vibration arm, but also in different amounts in the two vibration arms. This causes a problem in that the balance of the vibration arm is disrupted, leading to adverse effects due to vibration leakage.

[0012] Furthermore, since the weight film 750 is melted in the downward state, Figure 8 As shown in (a), the debris 751 formed on the main surface is in a rolled-up state and may be peeled off due to vibration. If the debris falls due to vibration, the left and right balance of the vibration arm may be disrupted, and the frequency may be affected by the change in weight.

[0013] Typically, as the piezoelectric vibrating reed becomes smaller, the weight film 750 needs to be thicker to ensure weight. Consequently, when the weight film 750 is removed by laser Ln melting, debris 751 is more likely to form. Therefore, the smaller the piezoelectric vibrating reed, the greater the problem of left-right balance loss or vibration leakage caused by debris.

[0014] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Laid-Open No. 2003-133879. Summary of the Invention

[0015] Problems to be solved by the invention An object of the present invention is to suppress the instability of vibration caused by the followability of vibration (amplitude) in a tuning-fork type piezoelectric vibration piece.

[0016] Solutions for solving problems (1) In the invention described in technical solution 1, there is provided a piezoelectric vibrating piece formed of quartz into a tuning fork shape and mounted in a package having a mounting portion on the inner side, characterized in that it comprises: a base; a pair of vibrating arm portions extending in parallel from the aforementioned base; two systems of electrodes formed on the aforementioned pair of vibrating arm portions; and a weight film for frequency adjustment, which has a first thickness portion formed of metal at the front end portion of the aforementioned vibrating arm portion, and an inclined portion, the inclined portion having an inclined surface formed continuously with the aforementioned first thickness portion on at least one side of the aforementioned base portion side and the front end side, the thickness of which gradually becomes thinner than that of the aforementioned first thickness portion.

[0017] (2) In the invention described in claim 2, there is provided a piezoelectric vibrating piece according to claim 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 a direction inclined relative to the longitudinal direction.

[0018] (3) In the invention described in Technical Solution 3, a piezoelectric vibrating piece according to Technical Solution 1 or Technical Solution 2 is provided, characterized in that the counterweight film has a second thickness portion formed thinner than the first thickness portion, and one side of the inclined portion is continuous with the first thickness portion, and the other side is continuous with the second thickness portion.

[0019] (4) In the invention described in claim 4, there is provided a piezoelectric vibrating piece according to claim 1 or claim 2, characterized in that, in the inclined portion of the weight film, one side in the longitudinal direction of the vibrating arm portion is continuous with the first thickness portion, and the other side is in contact with the main surface of the vibrating arm portion.

[0020] (5) In the invention described in claim 5, there is provided a piezoelectric vibrating piece according to any one of claims 1 to 4, characterized in that the inclined portion includes one or more inclined step portions between the one side and the other side in the longitudinal direction.

[0021] (6) In the invention described in claim 6, there is provided a piezoelectric vibrating piece according to any one of claims 1 to 4, characterized in that the length of the inclined portion in the direction of the inclined surface is at least half the spot diameter of the laser beam that forms the inclined portion.

[0022] (7) In the invention described in claim 7, there is provided a piezoelectric vibrating piece according to any one of claims 1 to 6, characterized in that the weight film is formed on at least one main surface of the front end portion of the vibrating arm portion.

[0023] (8) In the invention described in claim 8, there is provided a piezoelectric vibrating piece according to any one of claims 1 to 7, characterized in that the inclined portion of the weight film is formed on the front end side.

[0024] (9) In the invention described in Technical Solution 9, a piezoelectric vibrating piece according to any one of Technical Solutions 1 to Technical Solution 8 is provided, characterized in that it is a side arm type in which a support arm portion formed by extending from the base toward the outside of the vibrating arm portion is mounted on the mounting portion, a center arm type in which a support single arm portion formed by extending from the base to between the vibrating arm portions is mounted on the mounting portion, or a cantilever type in which the base portion is mounted on the mounting portion.

[0025] (10) In the invention described in claim 10, a piezoelectric vibrator is provided, characterized in that it comprises: a package having a mounting portion on the inside; a piezoelectric vibrating piece according to any one of claims 1 to 9 mounted on the mounting portion; and an external electrode portion formed from the mounting portion to the outside of the package.

[0026] (11) In the invention described in technical solution 11, a method for manufacturing a piezoelectric vibration piece is provided, which is characterized in that it comprises: an outer shape forming step of forming the outer shape of a tuning fork-type piezoelectric vibration piece, the tuning fork-type piezoelectric vibration piece having at least a base and a pair of vibration arm portions extending in parallel from the aforementioned base; an electrode forming step of forming two systems of electrodes on the aforementioned vibration arm portions; a weight film forming step of forming a weight film for frequency adjustment on the main surface of the front end side of the aforementioned vibration arm portion; and a frequency adjustment step of removing the aforementioned weight film to form an inclined portion having an inclined surface with a thickness gradually becoming thinner in at least a portion, thereby adjusting the frequency.

[0027] (12) In the invention described in claim 12, there is provided a method for manufacturing a piezoelectric vibrating piece according to claim 11, characterized in that the frequency adjustment step removes a portion of the weight film by non-thermal processing.

[0028] (13) In the invention described in claim 13, there is provided a method for manufacturing a piezoelectric vibrating piece according to claim 12, characterized in that the frequency adjustment step directly irradiates a non-thermal laser having a pulse width that allows removal of the weight film to be non-thermal.

[0029] (14) In the invention described in claim 14, there is provided a method for manufacturing a piezoelectric vibrating piece according to claim 13, characterized in that the non-thermal processing laser is a picosecond laser or a femtosecond laser having a pulse width of 2 bits or less.

[0030] (15) In the invention described in Technical Solution 15, a method for manufacturing a piezoelectric vibration piece according to any one of Technical Solutions 11 to 14 is provided, characterized in that, in the aforementioned frequency adjustment step, a coarse adjustment is performed on a first region on the front end side of the aforementioned vibration arm portion, and then a fine adjustment is performed on a second region closer to the aforementioned base portion side than the aforementioned first region.

[0031] (16) In the invention described in Technical Solution 16, a method for manufacturing a piezoelectric vibrator is provided, characterized in that it comprises: a process of manufacturing a piezoelectric vibrating piece through the processes of any one of Technical Solutions 11 to Technical Solution 15; a mounting process of mounting the aforementioned piezoelectric vibrating piece on a mounting portion formed in a package; and a sealing process of sealing the aforementioned package.

[0032] (17) In the invention described in claim 17, a method for manufacturing a piezoelectric vibrator according to claim 16 is provided, characterized in that it includes a final frequency adjustment step of performing ion trimming on the weight film of the mounted piezoelectric vibrating piece between the mounting step and the sealing step.

[0033] Effects of the Invention According to the present invention, the weight film formed at the front end of the vibration arm portion has an inclined portion formed continuously with the first thickness portion on at least one of the base side and the front end side, thereby reducing the presence of a steep step and further stabilizing the vibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is an explanatory diagram showing the shape of a weight film formed at the tip of a vibration arm portion of a piezoelectric vibration piece.

[0035] Figure 2 It is an explanatory diagram regarding a method of removing a weight film using the non-thermal processing laser Lf.

[0036] Figure 3 This is an explanatory diagram showing a state where a portion of the weight film is removed by the non-thermal processing laser light Lf.

[0037] Figure 4 It is an explanatory diagram showing a modified example of the shape of the weight film formed at the tip of the vibration arm portion.

[0038] Figure 5 It is an explanatory diagram showing the shape of the weight film in the second embodiment.

[0039] Figure 6 This is an exploded perspective view of a piezoelectric vibrator housing a piezoelectric vibrating reed.

[0040] Figure 7These are diagrams for explaining other shapes of piezoelectric vibrating reeds.

[0041] Figure 8 This is an explanatory diagram showing the state of the distal end of the vibrating arm portion after the weight film is melted and removed by laser in the related art. DETAILED DESCRIPTION

[0042] Below, refer to Figures 1 to 7 Preferred embodiments of the present invention will be described in detail.

[0043] (1) Overview of Implementation The piezoelectric vibrating reed of this embodiment is not removed by melting the entire predetermined region (total thickness) of the weight film 75 provided at the tip end portion of the vibrating arm portion 7 ( 7 a , 7 b ), but is removed by non-thermal processing.

[0044] When the weight film 75 is removed by non-thermal processing, the removed end portion (the longitudinal end portion of the vibrating arm portion 7) is formed so as to gradually become thinner along the longitudinal direction. In other words, an inclined portion B is formed that is continuous with the original thickness portion (first thickness portion C) and gradually becomes thinner.

[0045] The end portion of the inclined portion B on the opposite side 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 is removed by non-thermal working to be thinner than the first thickness portion C.

[0046] Thus, the weight film 75 is formed with thicknesses and inclined surfaces that differ depending on the region, and is formed into a shape having an inclined step.

[0047] The weight film 75 is not removed by melting, but by non-thermal processing by directly irradiating the weight film 75 with the non-thermal processing laser light Lf. Here, the non-thermal processing laser light Lf uses a laser having a pulse width capable of non-thermal processing of the weight film 75, that is, a laser having a pulse width of picoseconds (less than 2 digits, for example, 15 picoseconds) to femtoseconds, such as a femtosecond laser.

[0048] Using this non-thermal processing laser Lf, the upper surface side is removed while retaining a thickness of nμm (n<N) relative to the thickness Nμm of the counterweight film 75 before processing, thereby forming a second thickness portion A, and an inclined portion B with a gradually thinning thickness is formed between the first thickness portion C (thickness Nμm) which is the unprocessed portion and the second thickness portion A.

[0049] In the second thickness portion A, the removed thickness is adjusted by the number of times and / or the pulse width of scanning the region with the non-thermal processing laser light Lf.

[0050] On the other hand, the inclined portion B is formed by decreasing the number of scans, decreasing the pulse width, or decreasing the output energy from the second thickness portion A side toward the first thickness portion C side.

[0051] In this manner, athermal processing using the athermal processing laser Lf forms an inclined portion B continuous with the first thickness portion C in the frequency adjustment weight film 75, thereby reducing the presence of a steep step. In other words, by forming the cross-sectional shape of the weight film 75 with an inclined step, vibration can be further stabilized.

[0052] Furthermore, the formation of the second thickness portion A enables high-precision frequency adjustment, thereby improving the frequency accuracy of the piezoelectric vibrating piece 6 .

[0053] Furthermore, since the athermal processing is performed using the athermal laser Lf, the generation of debris caused by melting and removal can be eliminated. This allows frequency adjustment to be performed to achieve a balance not only for each vibration arm portion 7 but also between the two vibration arms 7a and 7b, thereby suppressing vibration leakage.

[0054] Furthermore, since there is no debris on the weight film 75 after the frequency adjustment, it is possible to prevent the debris from falling off due to vibration and causing the frequency to change.

[0055] (2) Details of the First Embodiment The first embodiment is a tuning fork type piezoelectric vibrating piece 6 using quartz. Figure 6 As will be described later, a pair of vibration arm portions 7 ( 7 a , 7 b ) extend from the base portion 8 , and support arm portions 9 ( 9 a , 9 b ) are formed for supporting the piezoelectric vibration piece 6 in the package 2 .

[0056] Grooves 72 of a certain width are formed along the longitudinal direction of the principal surfaces (rear surfaces) of the pair of vibrating arm portions 7. Two different systems of excitation electrodes 91 and 92, functioning as first and second excitation electrodes, are formed on the side surfaces and principal surfaces constituting the outer circumference of the vibrating arm portions 7, and within the grooves 72.

[0057] In addition, including each modified example described later, the groove portion 72 may not be formed in the vibrating arm portion 7 . However, in the case where the groove portion 72 is not formed, the first and second excitation electrodes are formed on the main surface.

[0058] Furthermore, a weight film 75 for frequency adjustment is formed at a front end portion in the longitudinal direction of the vibration arm portion 7 (on the front end side of the groove portion 72 ).

[0059] Figure 1 : is a diagram showing the shape of the tip of the vibration arm portion 7 in the piezoelectric vibration piece of this embodiment. Figures 1 to 5In FIG, the front end portion of one of the pair of vibrating arm portions 7 is shown. In addition, in each figure, the filled portion is Figure 5 The weighted membrane 75 is shown outside. Figure 5 The cross section of the weight film 75 is shown in FIG.

[0060] like Figure 1 As shown, at the tip of the vibration arm portion 7, a frequency adjustment weight film 75 is formed on the entire main surface. This weight film 75 is formed using a metal material such as Au or Ag by various methods such as vacuum evaporation to a predetermined thickness of Nμm. In this embodiment, the weight film 75 is formed to a predetermined thickness of Nμm = 3μm. However, the thickness Nμm can be appropriately selected based on various conditions, such as the size of the piezoelectric vibration piece to be manufactured, various forms such as the center arm type described later, and whether the tip of the vibration arm portion 7 is laterally widened (the size of the area where the weight film 75 is formed).

[0061] In addition, in the present embodiment, the weight film 75 is formed only on one main surface. However, since the weight film 75 is directly irradiated with the non-thermal processing laser beam Lf, it can also be formed on both surfaces or side surfaces.

[0062] The weight film 75 at the front end of the vibration arm portion 7 of this embodiment is as follows. Figure 1 As shown in (a) and (b), from the front end side in the longitudinal direction toward the base 8 side (left side of the picture, Figure 6 ) is formed with a second thickness portion A, an inclined portion B, and a first thickness portion C.

[0063] like Figure 1 As shown in (b), the first thickness portion C is a region that has not been processed by the non-thermal processing laser light Lf and has the original film thickness of N μm.

[0064] On the other hand, the inclined portion B and the second thickness portion A are portions of the weight film 75 that have been partially removed by processing with the non-thermal processing laser Lf. By using the non-thermal processing laser Lf, the entire thickness of the weight film 75 can be removed in the thickness direction, or only a portion of the thickness can be removed. In this embodiment, only a portion is removed.

[0065] The second thickness portion A is a portion removed parallel to the main surface of the vibrating arm portion 7, leaving only a thickness of n μm (n < N). This second thickness portion A is located on the front end side of the vibrating arm portion 7 and, as will be described later, is the portion where a portion of the weight film 75 is removed during frequency adjustment.

[0066] The inclined portion B is continuous with the first thickness portion C on the base 8 side and continuous with the second thickness portion A on the front end side, thereby forming an inclined surface whose thickness gradually decreases from the base 8 side toward the front end side.

[0067] The inclined portion B is a portion for adjusting the frequency by removing a portion of the weight film 75 and eliminating a steep step generated between the first thickness portion C and the second thickness portion A, thereby stabilizing the vibration of the vibrating arm portion 7 .

[0068] like Figure 1 As shown in (c), the inclination angle θ of the inclined portion B is within a range of greater than 0 degrees and less than 90 degrees (0°<θ<90°).

[0069] 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 practice, since the thickness (Nn) at the time of forming the inclined portion B is a predetermined value, the inclination angle θ is determined by the length.

[0070] The longitudinal length of the inclined portion B may be less than 1 / 2 of the spot diameter p1 of the non-thermal processing laser Lf, but is preferably not less than p / 2, and more preferably within a range of 1 to 2 times the spot diameter p1. The length of the inclined portion B is preferably a predetermined value selected to have a constant width and not change depending on the frequency adjustment amount (i.e., the weight removed is also a predetermined weight).

[0071] 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 amplitude. Specifically, the length of the second thickness portion A is determined by subtracting the predetermined weight removed from the inclined portion B from the weight of the weight film 75 removed, which is determined by the frequency adjustment amount. The length of the first thickness portion C is the length after removing the second thickness portion A and the inclined portion B.

[0072] The piezoelectric vibrator is formed in various sizes, but the effect of this embodiment can be more effectively achieved when the piezoelectric vibrator housing the piezoelectric vibrating reed is particularly small, such as 2.0×1.2 mm, 1.6 mm×1.0 mm, or 1.2 mm×1.00 mm.

[0073] The piezoelectric vibrating piece is formed according to the size of the piezoelectric vibrator. For example, in the case of a piezoelectric vibrator having a size of 1.6 mm×1.0 mm, the piezoelectric vibrating piece is formed to have a length of approximately 1 mm×a width of approximately 0.5 mm and a thickness of approximately 0.1 mm.

[0074] On the other hand, at the front end portion of the vibration arm portion 7, before the frequency adjustment based on the non-thermal processing laser Lf, the counterweight film 75 is formed to have a thickness N = 3 μm of the first thickness portion C, and the area and thickness of the counterweight film 75 to be removed are determined according to the required frequency adjustment amount for each area.

[0075] The frequency sensitivity of the tuning-fork type piezoelectric vibration piece increases from the base side toward the tip side of the vibration arm portion 7 .

[0076] Therefore, in frequency adjustment, it is effective to perform rough adjustment on the area on the front end side of the weight film 75 and perform fine adjustment on the area on the base portion 8 side.

[0077] In this embodiment, if Figure 1 As shown in (b), the frequency adjustment is completed by removing the second thickness portion A and the inclined portion B.

[0078] However, when further fine-tuning the frequency is performed after the frequency adjustment based on the removal of the second thickness portion A and the inclined portion B, this can be performed by removing the base 8 side of the first thickness portion C. In this case, only the inclined portion (inclined opposite to the inclined portion B) can be formed on the base 8 side, or a third thickness portion with a thickness of n2 μm (n2 < N) and the inclined portion can be formed.

[0079] Alternatively, the frequency can be roughly adjusted by further removing the front end of the weight film 75 until the main surface of the vibrating arm portion 7 is exposed, and fine-tuning can be performed on the front side thereof using the second thickness portion A and the inclined portion B. In this case, an inclined portion can be formed between the front end of the second thickness portion A and the main surface of the vibrating arm portion 7, thereby further reducing the steep step.

[0080] The following description targets Figure 1 Details of various variations of the illustrated embodiment.

[0081] 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.

[0082] Figure 2 This is an explanatory diagram of a method for removing the weight film 75 using the non-thermal processing laser Lf. Figure 2 (a) is a top view, and (b) to (d) are cross-sectional views in the longitudinal direction.

[0083] like Figure 2 As shown in (a), a weight film 75 having a predetermined thickness N (=3 μm) is formed at the front end of the vibration arm portion 7. Figure 2 The weight film 75 of the present embodiment shown is formed on one main surface of the vibration arm portion 7 , but may be formed on both surfaces or on the entire circumference including the side surfaces.

[0084] Make the weight film 75 face upward, as shown in FIG. Figure 2 As shown in (b), the weight film 75 is irradiated directly (without passing through the vibration arm portion 7) with the athermal laser light Lf, thereby removing the weight film 75 by a predetermined thickness (Nn) μm by athermal processing.

[0085] 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. By scanning the non-thermal processing laser Lf in the width direction, the reciprocating direction, and the longitudinal direction at a moving pitch p2 (for example, p2 = p1 / 2 = 5 μm), a predetermined area of ​​the weight film 75 is removed. Figure 2 In (a), the circle at the tip of the weight film 75 represents the spot diameter p1 of the non-thermal processing laser light Lf, and shows the state of the weight film 75 being moved in the width direction by a movement pitch p2 so that the spot diameter p1 partially overlaps. The weight film 75 is then removed from a predetermined area by moving in the width direction at the movement pitch p2 while also moving in the length direction.

[0086] During this trimming process, the non-thermal machining laser Lf is scanned in region A where the second thickness portion A is formed, removing a thickness of (Nn) μm from the weight film 75, based on the thickness N μm. This allows for frequency adjustment. By repeatedly measuring the deviation from the target frequency based on frequency measurement and removing the area (weight) corresponding to the deviation, the target frequency is gradually approached. Furthermore, in this embodiment, weight is removed from region A to account for the weight of the inclined portion B formed after the second thickness portion A is formed.

[0087] If the deviation from the desired frequency (target frequency) is large, this is addressed by expanding the area A of the second thickness portion A and reducing its thickness. For even greater deviations, the front-most portion of the weight film 75, where the frequency adjustment effect is greater, is completely removed all the way to the main surface of the vibrating arm portion 7. The front side of the removed portion is then partially removed to form the second thickness portion A and the inclined portion B, allowing for finer adjustments. If further fine-tuning is required, the frequency can be fine-tuned by removing the base portion 8 of the weight film 75.

[0088] After the second thickness portion A is removed, Figure 2 As shown in (c), an inclined portion B having an inclined surface is formed between the second thickness portion A and the first thickness portion C.

[0089] Figure 2 (d) is an enlarged view showing a state where the inclined portion B is formed.

[0090] like Figure 2 As shown in (d), the actual inclined portion B is not a flat plane state, but is formed by steps caused by a small step difference (at least two steps between the first thickness portion C and the second thickness portion A) and an inclined surface.

[0091] The continuous small steps in the inclined portion B are formed by machining the side surface with the non-thermal machining laser Lf and changing the number of scans.

[0092] exist Figure 2 In (d), after the non-thermal processing laser Lf, the numbers shown in parentheses illustrate the number of reciprocal scans for one line. For example, Lf(3) indicates that the line is reciprocated three times.

[0093] If the Figure 2 As shown in (d), for example, the second thickness portion A is formed by reciprocating the non-thermal processing laser Lf(3) three times on each line. Then, the non-thermal processing laser Lf(2) is reciprocated twice on the line moved by a predetermined movement pitch p3, and the non-thermal processing laser Lf(1) is reciprocated once on the line moved by the movement pitch p3.

[0094] As a result, a small step difference based on two reciprocating scans and one reciprocating scan is formed between the second thickness portion A based on three reciprocating scans and the unprocessed first thickness portion C, thereby suppressing a sudden thickness change.

[0095] Furthermore, the slightly curved inclined surfaces at both the upper and lower sides of each step further suppress a sharp change in thickness caused by the small step.

[0096] For example, in the processing based on the non-thermal processing laser Lf, such as Figure 2 As shown in the cross section (d), the processed end is not at a right angle to the processed surface (the irradiated surface), but rather forms a slightly inclined surface (curved surface) due to the energy distribution. This inclined surface is convex on the upper side of the processed end and concave on the lower side (on the vibrating arm portion 7 side). These upper and lower curved surfaces form a portion of the inclined portion B.

[0097] However, in Figure 2 In (d), the inclined surface outside the spot diameter is exaggerated for conceptual explanation.

[0098] In addition, although Figure 2 In the example shown in (d), the number of movements of the non-thermal processing laser Lf (2) and the non-thermal processing laser Lf (1) in the longitudinal direction (the number of movements based on the movement pitch p3) is set to 1 each, but by increasing the number of movements, it is possible to Figure 1 The tilt angle θ shown in (c) is adjusted to be smaller. Alternatively, the tilt angle θ can be adjusted to be larger by narrowing the movement pitch p3 based on the non-thermal processing laser Lf or omitting either the non-thermal processing laser Lf(2) or the non-thermal processing laser Lf(1).

[0099] Figure 3The diagram shows a state where a portion of the weight film 75 is removed by the non-thermal processing laser light Lf. (a) is a diagram showing a side cross section, and (b) is a diagram showing the top surface.

[0100] In conventional laser Ln with a pulse width of nanoseconds to picoseconds (3 digits), the weight film in the irradiated area is melted and removed entirely by heat, so that Figure 8 As shown, debris is generated at the boundary surface of the irradiated area, making it difficult to adjust the frequency of a further miniaturized piezoelectric vibrating piece. Furthermore, the debris may disrupt the balance between the vibrating arms and cause vibration leakage.

[0101] In contrast, the athermal laser Lf of this embodiment irradiates the surface of the weight film 75 with a pulsed laser of femtosecond units, thereby converting solid constituent materials into atoms, molecules, or plasma states and explosively releasing (ablating) them, thereby removing them by athermal processing.

[0102] Therefore, if Figure 3 As shown in (a), a portion of the weight film 75 in the thickness direction can be removed in the irradiation area of ​​the athermal laser Lf to form the second thickness portion A and the inclined portion B. As a result, high-precision frequency adjustment can be performed even on a more compact piezoelectric vibrating piece.

[0103] In addition, if Figure 3 As shown in (b), no debris is generated at the boundary of the irradiation area of ​​the non-thermal processing laser Lf, and thus the roughness of the boundary surface in the width direction at the boundary between the second thickness portion A and the inclined portion B, and at the boundary between the inclined portion B and the first thickness portion C (the deviation amplitude of the processing end caused by the irradiation of the non-thermal processing laser Lf relative to the imaginary straight line in the width direction orthogonal to the center line P) is suppressed to approximately 1 / 2 of the spot diameter of the non-thermal processing laser Lf.

[0104] In this embodiment, since the non-thermal processing laser Lf having a spot diameter of 10 μm is used as described above, the actual deviation width is suppressed to about w2=5 μm. Figure 8 Compared with the conventional width w1 = 20 μm shown, this is greatly suppressed.

[0105] As described above, according to the present embodiment, it is possible to eliminate the generation of debris and to achieve left-right balance with respect to the center line P of the vibrating arm portion 7 and balance between the two vibrating arm portions 7 .

[0106] By using this piezoelectric vibrating reed, a piezoelectric vibrator with even smaller vibration leakage can be formed.

[0107] The deviation width of the boundary surface depends on the spot diameter of the non-thermal processing laser Lf and the movement pitch p2. However, from the perspective of improving the balance accuracy of the vibration arm portion 7 and suppressing vibration leakage, the deviation width w2 is 10 μm or less, preferably 5 μm or less.

[0108] Next, a modification of the weight film 75 of this embodiment will be described.

[0109] exist Figure 1 In the embodiment described in , the formation surface of the weight film 75 of a predetermined thickness N formed on the main surface of the front end portion of the vibrating arm portion 7 is irradiated with a non-thermal processing laser Lf from an orthogonal direction (above), thereby forming a second thickness portion A, an inclined portion B, and a first thickness portion C.

[0110] In contrast, the following modifications (1) to (5) and various modifications based on combinations thereof are possible.

[0111] Deformation (1): The inclined surface of the inclined portion B is not directed toward the front end side, but toward the base 8 (refer to Figure 6 )side.

[0112] Deformation (2): The lower end of the inclined portion B is formed so as to contact the quartz. That is, the weight film 75 closer to the tip / base 8 than the lower end of the inclined portion B is completely removed until reaching the main surface of the vibrating arm portion 7 .

[0113] Deformation (3): Multiple inclined portions B are formed.

[0114] Modification (4): The thickness of the portion of the weight film 75 other than the inclined portion B is formed into three or more different thicknesses. In this case, a plurality of inclined portions B are inevitably formed.

[0115] Modification (5): The weight film 75 is formed on both surfaces, and an inclined portion B is formed on at least one of the surfaces.

[0116] Figure 4 1 and 2 are diagrams showing the shape of the weight film 75 based on a modification example adopting any one or more of the above-mentioned modifications (1) to (5).

[0117] Figure 4 (a) is when the above-mentioned variation (2) is adopted, by Figure 1 The weight film 75 shown is formed by removing all of the second thickness portion A formed on the front end without retaining it. Figure 2 In the scanning of the front end side described in (d), the number of reciprocating times of the femtosecond laser Lf is 3 to 4 times or more (in Figure 2 In the case of (d), four times), all of the weight film 75 in the region A is removed.

[0118] Figure 4 (b) is the case where the above-mentioned variation (1) is adopted.

[0119] In this Figure 4 In the example (b), the weight film 75 is scanned from the base 8 side toward the front end side, and the second thickness portion A is formed on the base 8 side, and then the inclined portion B toward the base 8 side is formed.

[0120] In addition, including Figure 2 The embodiment and all the variations described in the above are described for the case where the thinner portion (e.g., the second thickness portion A) is first locked and then the inclined portion B is formed toward the thicker portion (e.g., the first thickness portion C), but the opposite is also possible. Figure 2 In the example of (d), it is also possible to form an inclined portion B from the first thickness portion C side of the thicker portion in the order of non-thermal processing laser Lf(1) and non-thermal processing laser Lf(2) from the upper side to the lower side, and then form the second thickness portion A.

[0121] Figure 4 (c) is a case where the above-mentioned variations (3) and (1) are adopted.

[0122] In this Figure 4 In the example (c), second thickness portions A are formed at two locations on both sides of the front end side and the base 8 side, and inclined portions B1 and B2 facing in opposite directions are formed from the two second thickness portions A toward the central first thickness portion C.

[0123] exist Figure 4 In the example (c), the non-thermal machining laser Lf is moved from the tip side toward the base 8 side, thereby skipping the second thickness portion A, the inclined portion B1, and the first thickness portion C on the tip side and forming the inclined portion B2 and the second thickness portion A. Alternatively, after the second thickness portion A and the inclined portion B1 on the tip side are formed in this order, the non-thermal machining laser Lf may be positioned and moved in a different direction to form the second thickness portion A and the inclined portion B2 on the base 8 side.

[0124] In addition, Figure 4 In the modification shown in (c), modification (2) may also be applied so that at least a portion of the second thickness portion A on the front end side and the second thickness portion A on the base 8 side are completely removed.

[0125] Figure 4 (d) is the case where the above-mentioned deformation (3) and deformation (1) are adopted.

[0126] Figure 4(d) is a modification example opposite to (c), in which a second thickness portion A is formed at a central location, and opposite inclined portions B1 and B2 are formed on both sides thereof in a facing manner, and a first thickness portion C is formed at two locations further outward (front end side and base 8 side).

[0127] Figure 4 (e) is the case where the above-mentioned deformation (3), deformation (1), and deformation (4) are adopted.

[0128] Figure 4 (e) Similar to the modified example of (c), inclined portions B1 and B2 are formed on the front end and base 8 sides of the first thickness portion C formed in the center. However, unlike (c), a second thickness portion A2 is formed on the base 8 side, and a second thickness portion A1 (third thickness portion) thicker than second thickness portion A2 is formed on the front end. Alternatively, second thickness portion A1 may be formed on the base 8 side and on the front end.

[0129] Figure 4 (f) is the case where the above-mentioned deformation (1), deformation (3) and deformation (4) are adopted.

[0130] Figure 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 order from the front end toward the base 8. As shown in the figure, in this modification, the two inclined portions B1 and B2 are formed in the same direction (toward the base 8).

[0131] In addition, you can also use Figure 4 The formation order of the first thickness portion C to the second thickness portion A2 shown in (f) is 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 are formed in sequence from the front end side toward the base 8.

[0132] Figure 4 (g) is the case where the above-mentioned variations (1) and (5) are adopted.

[0133] Figure 4 In the modification example (g), from the front end side of the vibration arm portion 7 toward the base portion 8 side, a first thickness portion C1, an inclined portion B1, and a second thickness portion A1 are formed on the main surface on one side, and a first thickness portion C2, an inclined portion B2, and a second thickness portion A2 are formed on the main surface on the other side.

[0134] Furthermore, although the second thickness portion A1 on one side and the second thickness portion A2 on the other side have the same thickness, the thickness of one side may be formed thicker than the other side.

[0135] Alternatively, the order of forming the second thickness portion A, the inclined portion B, and the first thickness portion C may be reversed, and the first thickness portion C may be formed on the base portion 8 side.

[0136] Next, a second embodiment of the shape of the weight film 75 will be described.

[0137] In the first embodiment, the inclined surface of the inclined portion B is oriented toward the longitudinal direction of the vibrating arm portion 7 (see Figure 2 ) is explained.

[0138] In contrast, 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 with respect to the longitudinal direction.

[0139] Figure 5 It is an explanatory diagram showing the shape of the weight film 75 in the second embodiment. Figure 5 (a) shows the plane of the tip of the vibrating arm portion 7 with the weight film 75 formed thereon, (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 (b) to (d), the cross sections of the weight film 75 are partially filled in.

[0140] like Figure 5 As shown, at the front end side where the coarse adjustment of the frequency is performed, the counterweight film 75 is removed throughout the entire width direction by irradiation with the non-thermal processing laser Lf until the main surface A0 of the vibration arm portion 7 is exposed. In the middle area where the fine adjustment is performed from the middle, the two end sides in the width direction are retained and the central part is removed.

[0141] In the middle area where this fine adjustment is made, as Figure 5 As shown in (a), as the scanning position of the non-thermal machining laser light Lf moves toward the base portion 8, the scanning width gradually narrows, and a portion of the inclined portion B is formed into a V-shaped recess.

[0142] like Figure 5 As shown, the V-shaped recessed portion is formed symmetrically in the width direction of the vibration arm portion 7 , thereby suppressing a change in the balance of vibration.

[0143] like Figure 5 As shown in (a) and (b), the inclined portion B of the second embodiment has inclined surfaces B1 facing the longitudinal direction on both left and right (width direction) sides of the front end side in the longitudinal direction and in the central part of the base 8 side in the longitudinal direction.

[0144] On the other hand, in the V-shaped concave portion, as shown in FIG. Figure 5As shown in (c) and (d), the inclined portion B has an inclined surface B2 and an inclined surface B3 that are inclined with respect to the longitudinal direction.

[0145] Furthermore, the inclination angles of the inclined surfaces B2 and B3 oriented in the direction inclined with respect to the longitudinal direction are more gradual than that of the inclined surface B1 oriented in the longitudinal direction.

[0146] Therefore, according to this 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 gradual slope than in the first embodiment, thereby further stabilizing the vibration of the vibrating arm portion 7 .

[0147] In the second embodiment described above, the case where the inclined portion B is formed by the inclined surface B1 facing the longitudinal direction and the inclined surfaces B2 and B3 facing the direction inclined relative to the longitudinal direction is described. In contrast, the inclined surface B may be formed only in the direction inclined relative to the longitudinal direction. In this case, the inclined surface may be formed so as to face the two vibrating arm portions 7a and 7b (see FIG. Figure 6 ) is formed toward the outside, or is formed toward the outside of either side (same direction).

[0148] The inclined surface of the inclined portion B is formed in a V-shape in a plan view, that is, a shape in which the center in the width direction of the vibrating arm portion 7 is concave, but may be formed in a convex shape (inverted V shape) in contrast.

[0149] In addition, the second embodiment describes a case where the end portion of the inclined portion B opposite the first thickness portion C abuts the main surface A0 of the vibrating arm portion 7. Specifically, rather than leaving a portion of the weight film 75 to form the second thickness portion A, the entire thickness direction is removed to expose the main surface A0. Alternatively, the second thickness portion A can be formed in the leading end region for coarse adjustment and the intermediate region for fine adjustment. In this case, by forming a V-shape when viewed from above, inclined surfaces (portions B2 and B3) that are inclined relative to the longitudinal direction are formed between the first thickness portion C and the second thickness portion A.

[0150] Furthermore, if Figure 4 As described in , the above (1) to (5) in the first embodiment and various modifications based on their combinations are also applicable to the second embodiment and its modifications.

[0151] The shape and formation of the weight film 75 formed at the front end of the piezoelectric vibrating piece in the first and second embodiments and the modified example have been described above.

[0152] Next, the piezoelectric vibrating reed formed in this manner and the piezoelectric vibrator housing the piezoelectric vibrating reed will be described.

[0153] Figure 6 This is an exploded perspective view of a piezoelectric vibrator housing a piezoelectric vibrating reed.

[0154] like Figure 6 As shown, the piezoelectric vibrator 1 of this embodiment is a surface-mount vibrator of a ceramic package type, and includes a package 2 having an airtightly sealed cavity C therein, and a piezoelectric vibrating reed 6 housed in the cavity C.

[0155] The piezoelectric vibrator 1 of this embodiment has a bilaterally symmetrical structure. Therefore, two symmetrically arranged parts, such as the vibrating arm portion 7a and the vibrating arm portion 7b, are denoted by the same reference numerals. To distinguish the two parts, one is denoted by distinguishing symbols a and A, and the other is denoted by distinguishing symbols b and B. However, although distinguishing symbols are omitted as appropriate in the description, in this case, the respective parts are referred to.

[0156] The piezoelectric vibrating reed 6 is a so-called tuning-fork type vibrating reed formed from a piezoelectric material such as quartz, lithium tantalate, or lithium niobate. It vibrates when a predetermined voltage is applied. In this embodiment, a so-called side-arm type piezoelectric vibrating reed 6 formed from quartz as the piezoelectric material is used as an example.

[0157] The piezoelectric vibrating piece 6 includes vibrating arms 7 a and 7 b extending in parallel from the base 8 and supporting arms 9 a and 9 b extending from the base 8 in the same direction outside the vibrating arms 7 a and 7 b . The piezoelectric vibrating piece 6 is held in the cavity C by the supporting arms 9 a and 9 b .

[0158] The pair of vibrating arm portions 7 a and 7 b are arranged parallel to each other, and vibrate with the end portion on the base portion 8 side serving as a fixed end and the front end serving as a free end.

[0159] The pair of vibrating arms 7a and 7b have widened portions 71a and 71b at their distal ends, extending toward the sides relative to the approximate center of their overall length. These widened portions 71a and 71b increase the weight of the vibrating arms 7a and 7b and their moment of inertia during vibration. This facilitates vibration of the vibrating arms 7a and 7b, shortening their length and miniaturizing them.

[0160] Furthermore, on the main surfaces of the widened portions 71a and 71b, there are formed Figure 1 The weight film 75 with different thicknesses as described in .

[0161] In addition, although 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 difference is formed on the widened portions 71a and 71b, a piezoelectric vibrating piece without the widened portions 71a and 71b can also be used, in which the width of the front end portion of the vibrating arm portion 7 is formed to be approximately the same as the width of the central portion.

[0162] Grooves 72a and 72b extending from the base 8 to the front of the widened portions 71a and 71b are formed on both main surfaces of the vibrating arm portions 7a and 7b. As a result, the cross-sectional shape of the vibrating arm portions 7a and 7b becomes H-shaped.

[0163] On the outer surface (outer peripheral surface) of a pair of vibration arm portions 7a and 7b, a pair (two systems) of excitation electrodes (not shown) are formed, which are composed of a first system formed by the two side surfaces on the outer side of the vibration arm portion 7a and the groove portion 72b of the vibration arm portion 7b, and a second system formed by the two side surfaces on the outer side of the vibration arm portion 7b and the groove portion 72a of the vibration arm portion 7a.

[0164] In addition, although not shown in the figure, the first mounting 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 the second mounting 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.

[0165] The excitation electrode and the mount electrode are laminated films composed of a first chromium (Cr) layer and a second gold (Au) layer, and are formed by electrode sputtering or the like.

[0166] The package 2 is formed in a substantially rectangular parallelepiped shape and includes a package body 3 and a sealing plate 4 bonded to the package body 3 and forming a cavity C between the package body 3 and the sealing plate 4 .

[0167] The package body 3 includes a first base substrate 10 and a second base substrate 11 that are bonded to each other in a superposed state, and a seal ring 12 bonded to the second base substrate 11 .

[0168] The upper surface of the first base substrate 10 corresponds to the bottom surface of the cavity C.

[0169] The second base substrate 11 overlaps with 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 and the first base substrate 10 are integrated.

[0170] Furthermore, a connection electrode (not shown) is formed between the first base substrate 10 and the second base substrate 11 in a state of being sandwiched between the two base substrates 10 and 11 .

[0171] A through portion 11 a constituting a portion of the side wall of the cavity C is formed in the second base substrate 11 .

[0172] Mounting portions 14A and 14B that protrude inward are provided on inner side surfaces of both sides of the through portion 11 a that face each other in the short-side direction.

[0173] A pair of electrode pads (electrode portions) 20A and 20B are formed on the upper surfaces of the mounting portions 14A and 14B as connection electrodes for the piezoelectric vibrating reed 6. Furthermore, a pair of external electrodes 21A and 21B are formed on the lower surface of the first base substrate 10, spaced apart in the longitudinal direction of the package 2. The electrode pads 20A and 20B and the external electrodes 21A and 21B are formed as single-layer films of a single metal, or as laminated films of different metals, formed by, for example, vapor deposition or sputtering.

[0174] The electrode pads 20A, 20B and the external electrodes 21A, 21B are respectively connected to each other via the second through electrodes (not shown) formed on the mounting portions 14A, 14B of the second base substrate 11, the connecting electrodes (not shown) formed between the first base substrate 10 and the second base substrate 11, and the first through electrodes (not shown) formed on the first base substrate 10.

[0175] On the other hand, a conductive adhesive 51 is applied to the electrode pads 20A and 20B, and they are bonded to the mount electrodes of the support arm portions 9a and 9b.

[0176] The sealing ring 12 is a conductive frame-shaped member that is slightly smaller than the outer dimensions of the first and second base substrates 10 and 11, and is bonded to the upper surface of the second base substrate 11. Specifically, the sealing ring 12 is bonded by, for example, welding a metal bonding layer to the second base substrate 11 using a solder such as silver solder or a tin solder, or by forming the metal bonding layer on the second base substrate 11 (for example, by evaporation, sputtering, or the like, in addition to electrolytic or electroless plating).

[0177] The sealing plate 4 is a conductive substrate superimposed on the sealing ring 12 and is airtightly bonded to the package body 3 by bonding to the sealing ring 12. Furthermore, the space defined by the sealing plate 4, the sealing ring 12, the through portion 11a of the second base substrate 11, and the upper surface of the first base substrate 10 functions as an airtightly sealed cavity C.

[0178] Figure 6 The piezoelectric vibrator 1 shown is formed through the following steps.

[0179] (1) Production of Piezoelectric Vibrating Reed (a) In the outer shape forming step, the outer shape of a tuning-fork type piezoelectric vibrating reed having a vibrating arm portion is formed using quartz.

[0180] (b) In the electrode forming step, two systems of excitation electrodes and mounting electrodes are formed.

[0181] (c) In the weight film 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 before or after the electrode forming step, or simultaneously.

[0182] (d) In the frequency adjustment step, the non-thermal processing laser light Lf is directly irradiated onto the weight film 75 to remove an area and thickness corresponding to the frequency adjustment range, thereby forming the second thickness portion A and the inclined portion B. In the frequency adjustment step, rough adjustment is performed by removing the tip side and fine adjustment is performed by removing the base 8 side.

[0183] (2) Manufacturing of the Piezoelectric Vibrator 1 (e) In the piezoelectric vibrating piece manufacturing process, the piezoelectric vibrating piece 6 is manufactured through the steps of (1).

[0184] (f) In the mounting step, the support arm portion 9 is bonded to the electrode pad 20 formed on the mounting portion 14 of the package body 3 using a conductive adhesive 51 , thereby mounting the manufactured piezoelectric vibrating reed 6 .

[0185] (g) In the sealing step, the package body 3 on which the piezoelectric vibrating reed 6 is mounted is sealed by the sealing plate 4 .

[0186] Furthermore, when manufacturing the piezoelectric vibrator 1 , a final frequency adjustment step may be performed between the mounting step and the sealing step.

[0187] (f-2) In the final frequency adjustment, the weight film 75 of the mounted piezoelectric vibrating piece 6 is ion trimmed.

[0188] Specifically, the frequency of the mounted piezoelectric vibrating piece 6 is measured, and the entire surface of the weight film 75 (first thickness portion C, inclined portion B, second thickness portion A) is ion trimmed to achieve a desired frequency, thereby performing final frequency adjustment.

[0189] In ion trimming, the portion other than the weight film 75 is masked, and unfocused argon ions accelerated to several thousand V are irradiated to grind (thin) the surface of the weight film 75 by sputtering.

[0190] In this embodiment, the weight film 75 formed on the main surface is not entirely melted and removed in the thickness direction. Instead, it is irradiated with the non-thermal processing laser Lf to thin a portion of the weight film in the thickness direction, thereby forming the second thickness portion A and the inclined portion B. That is, although the thickness of the weight film 75 formed on the main surface in the weight film forming step (c) decreases depending on the area, the area on the main surface remains the same.

[0191] Therefore, since the target area of ​​the ion trimming is large (maintaining the initial formed area), the weight film 75 of a predetermined weight can be removed by ion trimming in a short time.

[0192] The structures of the side-arm type piezoelectric vibrating piece 6 and the piezoelectric vibrator 1 using the same have been described above. However, the weight film 75 having an inclined step can be formed on other types of piezoelectric vibrating pieces as long as they are tuning fork type.

[0193] Figure 7 Regarding other types of piezoelectric vibrating reeds, (a) is an explanatory diagram showing a cantilever-type piezoelectric vibrating reed 61 , and (b) is an explanatory diagram showing a center-arm-type piezoelectric vibrating reed 62 .

[0194] Figure 7 The piezoelectric vibrating piece 61 shown in (a) is formed with vibrating arm portions 7a and 7b extending in parallel from the base portion 8 in the longitudinal direction, and does not have a supporting arm portion. Figure 7 The piezoelectric vibrating piece 62 shown in (b) has a supporting single arm portion 9 c formed between the vibrating arm portions 7 a and 7 b extending parallel to the longitudinal direction from the base portion 8 .

[0195] The two main surfaces of the pair of vibration arm portions 7a and 7b in the two piezoelectric vibration pieces 61 and 62 are Figure 6 The piezoelectric vibrating piece 6 described above is similarly formed with the grooves 72 a and 72 b.

[0196] Furthermore, first-system excitation electrodes 92 are formed on both outer side surfaces of the vibration arm portion 7a and the groove portion 72b of the vibration arm portion 7b, and second-system excitation electrodes 91 are formed on both outer side surfaces of the vibration arm portion 7b and the groove portion 72a of the vibration arm portion 7a.

[0197] Furthermore, the cantilever type piezoelectric vibrating piece 61 is as shown in FIG. Figure 7 As shown in (a), the base portion 8 is provided with first mount electrodes 92 m connected to the first system excitation electrodes 92 and second mount electrodes 91 m connected to the second system excitation electrodes 91 .

[0198] On the other hand, the center arm type piezoelectric vibrating piece 62 is as shown in FIG. Figure 7 As shown in (b), the first mounting electrode 92m connected to the first system excitation electrode 92 is formed from the base 8 to the front end of the supporting arm portion 9c, and the second mounting electrode 91m connected to the second system excitation electrode 91 is formed from the base 8 to the center of the supporting arm portion 9c.

[0199] The piezoelectric vibrating pieces 61 and 62 are both Figure 6 The piezoelectric vibrating reed 6 described above is similarly housed in the package 2 to constitute a piezoelectric vibrator.

[0200] In the package 2 in this case, a portion corresponding to the base portion 8 is formed at the position of the piezoelectric vibrating piece 61 and at the position of the supporting arm portion 9c at the position of the piezoelectric vibrating piece 62. Figure 6 The mounting portions corresponding to the mounting portions 14A and 14B described above are bonded and fixed to two systems of electrode pads formed on the mounting portions using a conductive adhesive.

[0201] Moreover, in Figure 7 In the cantilever-type piezoelectric vibrating piece 61 of (a), there is no widened portion 71 at the front end of the vibrating arm portion 7, while in the center-arm-type piezoelectric vibrating piece 62 of (b), a widened portion 71 is formed at the front end of the vibrating arm portion 7. In both piezoelectric vibrating pieces 61 and 62, a weight film 75 is formed at the front end of the vibrating arm portion 7. The cross section along the longitudinal direction thereof is as follows: Figure 1 As described in , the frequency is adjusted by irradiation with the non-thermal processing laser light Lf. Thus, the weight film 75 is formed with a thickness and an inclined surface that differ depending on the region, and is formed into a shape having an inclined step.

[0202] Explanation of symbols 1 Piezoelectric vibrator 2 Packaging 3 Package body 4 Sealing plate 6 Piezoelectric vibrating piece 7, 7a, 7b vibration arm 8 base 9, 9a, 9b support arm 9c Supporting one arm 10 first bottom substrate 11. Second bottom substrate 14, 14A, 14B installation part 20, 20A, 20A electrode pads 21, 21A, 21B external electrodes 51 Conductive adhesive 61, 62 Piezoelectric vibrating piece 72 groove 75 weighted membrane 91, 92 excitation electrodes 91m, 92m assembly electrodes C cavity

Claims

1. A piezoelectric vibrating piece made of quartz and formed into a tuning fork shape and mounted in a package having a mounting portion therein, characterized in that: have: base; a pair of vibrating arms extending in parallel from the base; Two systems of electrodes formed on the pair of vibrating arm portions; and The front end portion of the vibration arm portion is formed of a metal weight film for frequency adjustment. The weighted membrane has: a first thickness portion; a planar first inclined surface formed on at least one of the base side and the front end side of the first thickness portion and having a thickness gradually becoming thinner than that of the first thickness portion; as well as A first curved surface that is curved in a convex shape and continuously connects the first thickness portion and the first inclined surface.

2. The piezoelectric vibrating piece according to claim 1, wherein The first inclined surface is formed so that an end portion thereof on the opposite side to the first thickness portion comes into contact with the quartz surface of the vibrating arm portion.

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

4. The piezoelectric vibrating piece according to claim 3, wherein 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.

5. The piezoelectric vibrating piece according to claim 3 or claim 4, wherein: The weighted membrane has: a planar second inclined surface, which is opposed to the first inclined surface and is formed on a side of the second thickness portion opposite to the first inclined surface; as well as A third thickness portion is formed on the second inclined surface on the opposite side of the second thickness portion, and the third thickness portion is thinner than the first thickness portion and thicker than the second thickness portion.

6. The piezoelectric vibrating piece according to any one of claims 1 to 5, wherein: The weight film is formed on both surfaces of the vibration 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.

7. The piezoelectric vibrating piece according to any one of claims 1 to 6, wherein: The piezoelectric vibrating piece is a side arm type in which a supporting arm portion extending from the base toward the outside of the vibrating arm portion is mounted on the mounting portion, a center arm type in which a supporting single arm portion extending from the base to between the vibrating arm portions is mounted on the mounting portion, or a cantilever type in which the base is mounted on the mounting portion.

8. A piezoelectric vibrator, characterized in that: have: A package having a mounting portion on the inner side; The piezoelectric vibrating piece according to any one of claims 1 to 7 mounted on the mounting portion; and An external electrode portion is formed extending from the mounting portion to the outside of the package.

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