JP2007142526A - Piezoelectric wafer and piezoelectric device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric wafer whereby piezoelectric substrates keep their shapes even when the piezoelectric substrates are formed by etching the piezoelectric wafer and the piezoelectric substrates can easily be folded off from a piezoelectric wafer main body, and to provide a piezoelectric device. <P>SOLUTION: The piezoelectric wafer 10 is formed with the piezoelectric substrates 20, support parts 40, and the piezoelectric wafer main body 12 through etching. Each piezoelectric substrate 20 is connected to the piezoelectric wafer main body 12 by the support parts 40. That is, the support parts 40 are connected to an end of a face (substrate end face) 22 provided to a side of a substrate end 26 of each piezoelectric substrate 20. Outer side faces 46 of the support parts 40 are consecutively provided along side faces 24 of each piezoelectric substrate 20. Further, inner side faces 42 of the support parts 40 are configured to include first grooves 44 along the substrate end face 22 of each piezoelectric substrate 20. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a piezoelectric wafer and a piezoelectric device, and more particularly to a piezoelectric wafer in which a piezoelectric substrate is favorably broken from a piezoelectric wafer body and a piezoelectric device using the same.

Conventionally, a piezoelectric substrate is obtained as follows. FIG. 5 is an enlarged explanatory view of a part of a piezoelectric wafer according to the prior art. Here, the upper diagram of FIG. 5 is an enlarged plan view of one piezoelectric substrate formed on the piezoelectric wafer. Further, the figure shown in the circle on the lower side of FIG. 5 is an enlarged perspective view of the portion shown in the circle in the plan view.

A plurality of piezoelectric substrates 102 are formed on one piezoelectric wafer 101 by etching. That is, a protective film corresponding to the shape of the piezoelectric substrate 102 or the like is formed on the upper surface and the lower surface of the piezoelectric wafer 101, and this is immersed in an etching solution to remove portions other than the portion where the piezoelectric substrate 102 or the like is formed. 102 is formed. Each piezoelectric substrate 102 has a base end 103.
The piezoelectric wafer main body 112 is connected by support portions 111 connected to both ends of a surface (base end surface) 104 provided on the side. A groove 105 along the base end face 104 of the piezoelectric substrate 102 is formed in the support portion 111 at a location where it is connected to the piezoelectric substrate 102. This groove 105
Does not penetrate from the upper surface to the lower surface of the piezoelectric wafer 101, but near the center in the thickness direction.
11 and the piezoelectric substrate 102 are connected. The groove 105 is a cut when the piezoelectric substrate 102 is folded from the piezoelectric wafer body 112. If the groove 105 is not provided, the piezoelectric substrate 102 cannot be beautifully folded from the piezoelectric wafer body 112. That is, it may be broken from the place where the support 111 and the piezoelectric wafer body 112 are connected, or the piezoelectric substrate 10
It breaks at the place inside the 2.

Patent Document 1 discloses a method of individually separating crystal pieces produced by photolithography by etching. In the invention disclosed in Patent Document 1, a groove for dynamically weakening at least a part of a quartz wafer is provided in the vicinity of the breakout edge of the quartz piece. By providing this groove, it can be cut cleanly when a bending force is applied to the crystal piece.
Japanese National Patent Publication No. 11-509052

FIG. 6 is an explanatory view of entering after etching. Here, FIG. 6A is a plan view of the piezoelectric substrate formed on the piezoelectric wafer, and FIG. 6B is a cross-sectional view taken along the line AA of FIG. When the piezoelectric wafer 101 is etched to form the piezoelectric substrate 102 shown in FIG. 5, the side surface 107 along the −X direction from the corner portion 106 of the base end 103 of the piezoelectric substrate 102 shown in FIG.
Will be etched. That is, the intrusion 108 is caused by etching toward the inside of the piezoelectric substrate 102. In FIG. 6 (A), the hatched portion indicates the entry 10.
8 is shown. Then, when AT-cut quartz is used for the piezoelectric substrate 102, the penetration 108 generated on the side surface 107a provided in the + ZZ ′ direction of the piezoelectric substrate 102 is
It is greatly generated by the lower surface 110 of 02. Further, the intrusion 108 generated on the side surface 107 b provided in the −ZZ ′ direction is greatly generated on the upper surface 109 of the piezoelectric substrate 102. Such an intrusion 108 occurs due to anisotropic etching due to the crystal axis of the piezoelectric substrate 102. If the piezoelectric vibrating piece is formed with the piezoelectric substrate 102 in which such an intrusion 108 has occurred, the vibration region of the piezoelectric vibrating piece cannot be secured to the maximum, and there is a problem that the vibration characteristics deteriorate.
In recent years, since the piezoelectric vibrating piece has been reduced in size, there is a problem that when the planar shape of the piezoelectric substrate 102 is reduced, the upper surface 109 and the lower surface 110 of the piezoelectric substrate 102 are almost filled with the entry 108.

Further, the vibration characteristics and the like of the piezoelectric vibrating piece depend on the shape of the piezoelectric substrate 102. That is, when the side surface 107 of the piezoelectric vibrating piece is formed perpendicular to the upper surface 109 (lower surface 110), the vibration characteristics and the like of the piezoelectric vibrating piece are improved. In order to obtain a piezoelectric vibrating piece having such a shape, the piezoelectric substrate 102
It is known that the etching time for forming the film may be increased. However, since the intrusion 108 is generated by etching, there is a problem that the amount of the intrusion 108 increases as the etching time is increased.
An object of the present invention is to provide a piezoelectric wafer and a piezoelectric device that maintain the shape of the piezoelectric substrate even when the piezoelectric wafer is etched to form the piezoelectric substrate, and that the piezoelectric substrate can be easily folded from the piezoelectric wafer body. To do.

The piezoelectric wafer according to the present invention is characterized in that support portions connected to the piezoelectric wafer main body are provided at both ends of the surface provided on the base end side of the piezoelectric substrate. The outer surface of the support portion is provided continuously along the side surface of the piezoelectric substrate. Further, the inner surface of the support portion is provided with a first groove along the surface provided on the base end side of the piezoelectric substrate. The side surface of the piezoelectric substrate intersects the surface provided on the base end side of the piezoelectric substrate.

Since the outer side surface of the support part and the side surface of the piezoelectric substrate are also continuous, there is no stagnation that causes penetration into the piezoelectric substrate by etching. Therefore, even if the piezoelectric wafer is immersed in the etching solution, the piezoelectric substrate does not enter and the shape of the piezoelectric substrate can be obtained as desired. Even if the etching time is extended or the shape of the piezoelectric substrate is reduced, the piezoelectric substrate does not enter, and the shape of the piezoelectric substrate is maintained even after etching. Can do. Further, since the support portion is provided with the first groove, the first groove becomes a base point when the piezoelectric substrate is separated from the support portion, and the piezoelectric substrate can be easily separated from the piezoelectric wafer body.

The piezoelectric wafer according to the present invention is characterized in that a second groove along the surface provided on the base end side of the piezoelectric substrate is provided on the outer surface of the support portion. In this case, the length of the second groove is shorter than the length of the first groove.

The second shorter than the first groove between the side surface of the piezoelectric substrate and the outer side surface of the support portion.
Therefore, the amount of intrusion generated in the piezoelectric substrate by etching can be made extremely small. For this reason, even if the etching time is increased in order to adjust the shape of the piezoelectric substrate, the shape does not deteriorate because the intrusion generated in the piezoelectric substrate is slight, and the shape of the piezoelectric substrate can be maintained. Further, even when the etching time is increased, the piezoelectric substrate does not enter, and the shape of the piezoelectric substrate can be maintained even when the etching is performed. Further, since the first groove and the second groove are provided in the support portion, the first groove and the second groove serve as a base point when the piezoelectric substrate is separated from the support portion, and the piezoelectric wafer main body is separated from the piezoelectric wafer body. The substrate can be easily separated.
The piezoelectric substrate is an AT cut crystal. Accordingly, the side surface along the X axis of the piezoelectric substrate does not enter and a piezoelectric substrate having a desired shape can be obtained.

The piezoelectric device according to the present invention is characterized in that an electrode pattern is provided on the piezoelectric substrate provided on the piezoelectric wafer having the characteristics described above, and the piezoelectric substrate is separated from the support portion. Since the side surface does not enter the inside of the piezoelectric substrate, if the piezoelectric device is formed using this piezoelectric substrate, the vibration region can be secured to the maximum. In such a piezoelectric device, various characteristics such as vibration characteristics can be improved and stabilization can be achieved.

The piezoelectric device according to the present invention is characterized in that the piezoelectric substrate provided with the electrode pattern is mounted on a package. As a result, the piezoelectric device can improve various characteristics such as vibration characteristics and can be stabilized.

The best embodiments of the piezoelectric wafer and the piezoelectric device according to the present invention will be described below. First, the first embodiment will be described. FIG. 1 is an enlarged plan view of a part of the piezoelectric wafer according to the first embodiment. FIG. 1 is an enlarged view of one piezoelectric substrate.
A plurality of piezoelectric substrates 20 are formed on the piezoelectric wafer 10 by etching. Each piezoelectric substrate 20 is connected to the piezoelectric wafer body 12 via a support portion 40. The piezoelectric substrate 20 is connected to the support portion 40 at both ends of the surface (base end surface) 22 provided on the base end 26 side. When an AT-cut crystal is used as the piezoelectric wafer 10, FIG.
As shown in FIG. 4, the side surface 24 of the piezoelectric substrate 20 is formed along the X axis.
4 is formed along the ZZ ′ axis. In FIG. 1, the direction from the base end 26 to the free end 28 of the piezoelectric substrate 20 is the −X direction, and the direction from the lower side to the upper side of the drawing is the + ZZ ′ direction.

Each support portion 40 has a first groove 44 in a surface (inner surface) 42 where the support portions 40 face each other.
Is provided. The first groove 44 is provided along the base end surface 22 of the piezoelectric substrate 20 and penetrates from the upper surface to the lower surface of the piezoelectric wafer 10. Further, the outer surface (outer surface) 46 of the support portion 40 is provided continuously to the side surface 24 of the piezoelectric substrate 20.

Next, a method for separating the piezoelectric substrate 20 and a method for manufacturing a piezoelectric vibrating piece (piezoelectric device) will be described. First, protective films (not shown) for the etching solution are formed on the upper and lower surfaces of the piezoelectric wafer 10. The protective film is formed on a portion where these are provided according to the shape of the piezoelectric substrate 20, the support portion 40, and the piezoelectric wafer body 12. Piezoelectric wafer 10 on which a protective film is formed
Is immersed in an etching solution, the portion not covered with the protective film is etched, and the upper and lower surfaces of the piezoelectric wafer 10 penetrate. Accordingly, the first groove 4 is formed on the inner surface 42 of the support portion 40.
4 is formed. Further, the outer surface 46 of the support portion 40 is formed continuously with the side surface 24 of the piezoelectric substrate 20. For this reason, the piezoelectric substrate 20 does not have an indentation caused by etching, so that no entry occurs from the corner of the base end 26.

Then, after an elapse of time for removing unnecessary portions of the piezoelectric wafer 10 and penetrating the upper and lower surfaces of the piezoelectric wafer 10, the piezoelectric wafer 10 is taken out of the etching solution. Etching time is
It is appropriately set according to the etching environment such as the concentration and temperature of the etching solution. Piezoelectric wafer 10
When removed from the etching solution, the protective film formed on the upper and lower surfaces is removed. As a result, the piezoelectric substrate 20 connected to the piezoelectric wafer body 12 via the support portion 40 is formed on the piezoelectric wafer 10.

Thereafter, electrode patterns are formed on the upper and lower surfaces of the piezoelectric substrate 20 formed on the piezoelectric wafer 10. FIG. 2 is a plan view of a piezoelectric substrate on which an electrode pattern is formed. In FIG. 2, the description of the support portion 40 connected to the piezoelectric substrate 20 is omitted. Each electrode pattern 30 includes an excitation electrode 32, a connection electrode 34, and a lead electrode 36. The electrode pattern 30 is formed, for example, by covering the piezoelectric wafer 10 with a jig having an opening corresponding to the shape of the electrode pattern 30 and forming a metal film on the piezoelectric substrate 20 exposed in the opening. It only has to be done. The electrode pattern 30 can also be formed using a photolithography technique. The excitation electrode 32 is provided at the center of the piezoelectric substrate 20. The connection electrodes 34 are provided at both ends of one side of the piezoelectric substrate 20. And the extraction electrode 3
6 connects the excitation electrode 32 and the connection electrode 34 on a one-to-one basis.

Thereafter, the piezoelectric substrate 20 is separated from the piezoelectric wafer 10. As a specific example of this separation method, the piezoelectric wafer 10 is first mounted on a fixing jig, and the piezoelectric wafer body 12 is held by the fixing jig. Then, a pin is pressed against the piezoelectric substrate 20 from above the piezoelectric substrate 20 to fold the piezoelectric substrate 20. At this time, the first groove 44 provided in the support portion 40 becomes a part of the folding, and the piezoelectric substrate 20 is folded from the portion where the first groove 44 is provided. In addition, since the first groove 44 is provided in the support portion 40 along the base end surface 22 of the piezoelectric substrate 20, even when the piezoelectric substrate 20 is folded, the broken cut surface is the same as that of the piezoelectric substrate 20. Along the base end face 22. Thereby, the piezoelectric substrate 20 is formed, and at the same time, the piezoelectric vibrating piece 38 is formed. Note that the electrode pattern 30 may be formed on the upper surface and the lower surface of the piezoelectric substrate 20 after the piezoelectric substrate 20 is broken from the piezoelectric wafer 10.

According to the piezoelectric wafer 10 and the piezoelectric vibrating piece 38 as described above, the side surface 24 along the X axis of the piezoelectric substrate 20 and the outer surface 46 of the support portion 40 are continuous. There is no. For this reason, even if the etching time is increased in order to adjust the shape of the piezoelectric substrate 20, the piezoelectric substrate 20 does not enter and the shape of the piezoelectric substrate 20 does not deteriorate. Therefore, the side surface shape of the piezoelectric substrate 20 can be uniformly finished on the outer periphery of the piezoelectric substrate 20.

Since the side surface does not enter the inside of the piezoelectric substrate 20, the vibration region can be secured to the maximum when the piezoelectric vibrating piece 38 is formed by the piezoelectric substrate 20. In such a piezoelectric vibrating piece 38,
Various characteristics such as vibration characteristics can be improved, and stabilization can be achieved.

Further, since the first groove 44 is provided in the support portion 40 connecting the piezoelectric substrate 20 and the piezoelectric wafer body 12, the piezoelectric substrate 20 can be easily folded from the piezoelectric wafer body 12. Further, the first groove 44 does not necessarily have to penetrate. The piezoelectric wafer 10 is made of A
Not only the T-cut quartz crystal but also other cut angles may be used.

Next, a second embodiment will be described. In the second embodiment, the same components as those of the piezoelectric wafer and the piezoelectric device described in the first embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted. FIG. 3 is an explanatory diagram enlarging a part of the piezoelectric wafer according to the second embodiment. 3A is an enlarged plan view of one piezoelectric substrate, and FIG. 3B is an enlarged plan view of a circled portion in FIG. 3A.

A plurality of piezoelectric substrates 20 are formed on the piezoelectric wafer 10 by etching, and both ends of the base end surface 22 of the piezoelectric substrate 20 and the piezoelectric wafer main body 12 are connected by a support unit 40. When AT-cut quartz is used as the piezoelectric wafer 10, the side surface 24 of the piezoelectric substrate 20 is formed along the X axis as shown in FIG. 3, and the surface intersecting the side surface 24 is ZZ. 'It is formed along the axis.

Each support portion 40 is provided with a first groove 44 on the inner side surface 42. The first groove 44 is provided along the base end surface 22 of the piezoelectric substrate 20 and penetrates from the upper surface to the lower surface of the piezoelectric wafer 10. Each support portion 40 is provided with a second groove 48 on the outer surface 46.
The second groove 48 is provided along the base end face 22 of the piezoelectric substrate 20, and the piezoelectric wafer 1
It penetrates from the upper surface to the lower surface of 0. The length a of the first groove 44 and the length b of the second groove 48 satisfy the relationship 0 <b <a.
A method for separating the piezoelectric substrate 20 and a method for manufacturing a piezoelectric vibrating piece (piezoelectric device) obtained from the piezoelectric substrate 20 may be the same as those described in the first embodiment.

According to the piezoelectric wafer 10 and the piezoelectric vibrating piece as described above, the second shorter than the first groove 44 between the side surface 24 along the X axis of the piezoelectric substrate 20 and the outer surface 46 of the support portion 40. Since the groove 48 is provided, the amount of intrusion generated by etching can be made extremely small. For this reason, even if the etching time is increased in order to adjust the shape of the piezoelectric substrate 20, the shape does not deteriorate because the penetration that occurs in the piezoelectric substrate 20 is slight. If a piezoelectric vibrating piece is formed with the piezoelectric substrate 20, the vibration region can be secured to the maximum. The piezoelectric substrate 20
The piezoelectric vibrating piece using can improve various characteristics such as vibration characteristics and can be further stabilized.
Further, since the first groove 44 and the second groove 48 are provided in the support portion 40 that connects the piezoelectric substrate 20 and the piezoelectric wafer body 12, the piezoelectric substrate 20 can be more easily folded from the piezoelectric wafer body 12. Can be taken.

The planar shape of the second groove 48 is rectangular in FIG. 3, but is not limited to this shape, and may be any shape such as a triangle or a semicircle. The first groove 44 and the second groove 48 do not necessarily have to penetrate. In addition, the piezoelectric wafer 10 may be not only AT-cut quartz but also one cut at another cut angle.

Next, a third embodiment will be described. In the third embodiment, a piezoelectric vibrator will be described. In the third embodiment, the same reference numerals are given to the same components as those described in the first and second embodiments. FIG. 4 is a cross-sectional view of the piezoelectric vibrator.
The piezoelectric vibrator 50 (piezoelectric device) has a configuration in which the piezoelectric vibrating piece 38 described in the first and second embodiments is mounted on a package 52. The package 52 includes a package base 54 and a lid 56. External terminals 58 are provided on the back surface of the package base 54.
Further, the package base 54 includes a recessed portion 60 that opens upward. This recess 60
A mount electrode 62 is provided on the bottom surface. The mount electrode 62 is electrically connected to the external terminal 58. On the mount electrode 62, the piezoelectric vibrating piece 3 is interposed via a conductive bonding material 64.
8 is installed. As a result, the mount electrode 62 and the connection electrode 34 of the piezoelectric vibrating piece 38 are electrically connected via the conductive bonding material 64. A lid 56 is bonded onto the package base 54 on which the piezoelectric vibrating piece 38 is mounted, and the recessed portion 60 is hermetically sealed.

In such a piezoelectric vibrator 50, since the piezoelectric substrate 20 which does not enter is used, it is possible to prevent various characteristics such as vibration characteristics from deteriorating. Further, even when the piezoelectric vibrator 50 having a reduced planar size is formed using the reduced piezoelectric vibrating piece 38,
Since no penetration occurs in the piezoelectric substrate 20, a vibration region can be secured and various characteristics such as vibration characteristics can be prevented from deteriorating.

The package 52 can also be equipped with a circuit that oscillates the piezoelectric vibrating piece 38.
The package 52 includes a circuit for oscillating the piezoelectric vibrating piece 38 and the piezoelectric vibrating piece 38.
It is also possible to mount a temperature compensation circuit that increases the frequency stability with respect to the temperature and a circuit that controls the output frequency of the piezoelectric vibrating piece 38 according to the set voltage.

It is the top view to which a part of piezoelectric wafer concerning a 1st embodiment was expanded. It is a top view of the piezoelectric substrate in which the electrode pattern was formed. It is explanatory drawing which expanded a part of piezoelectric wafer concerning 2nd Embodiment. It is sectional drawing of a piezoelectric vibrator. It is explanatory drawing which expanded a part of piezoelectric wafer which concerns on a prior art. It is explanatory drawing of the penetration after an etching.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ......... Piezoelectric wafer, 12 ......... Piezoelectric wafer main body, 20 ......... Piezoelectric substrate, 22 ......... Base end face, 26 ......... Base end, 30 ...... Electrode pattern, 38 ...... Piezoelectric vibrating piece , 40... Supporting part 42... Inner side surface 44... First groove 46... Outer surface 48 48 Second groove 50.

Claims (6)

A support portion connected to the piezoelectric wafer main body is provided at both ends of the surface provided on the base end side of the piezoelectric substrate,
The outer surface of the support portion is continuously provided along the side surface of the piezoelectric substrate,
A first groove along the surface provided on the base end side of the piezoelectric substrate is provided on the inner surface of the support portion.
A piezoelectric wafer characterized by that. 2. The piezoelectric wafer according to claim 1, wherein a second groove along the surface provided on the base end side of the piezoelectric substrate is provided on the outer surface of the support portion. The piezoelectric wafer according to claim 2, wherein a length of the second groove is shorter than a length of the first groove. 4. The piezoelectric wafer according to claim 1, wherein the piezoelectric substrate is an AT cut crystal. 5. A piezoelectric device comprising an electrode pattern provided on the piezoelectric substrate provided on the piezoelectric wafer according to claim 1, and the piezoelectric substrate being separated from the support portion. The piezoelectric device according to claim 5, wherein the piezoelectric substrate provided with the electrode pattern is mounted on a package.

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