JP2001156584A - Piezoelectric element and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric element where the occurrence of a short- circuit or a disconnection due to a defective shape of electrodes at a side end face can be prevented resulting from inaccurate formation of a resist mask 93 caused by defective exposure in the case of forming the resist mask 93 to continuously form electrodes 73 and 74 on upper and lower sides to the side end face of a piezoelectric element chip 62. SOLUTION: In the case of etching a crystal wafer to form a piezoelectric element chip 62, powder beam etching is executed thereby configuring the side end face of the piezoelectric element chip 62 with a slope whose middle part in the perpendicular direction is projected outward over the entire circumference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric element and a method of manufacturing the same, and more particularly, to a piezoelectric element used as a quartz oscillator or the like and a method of manufacturing the same.

[0002]

2. Description of the Related Art As shown in FIG. 1, a tuning fork type crystal oscillator among various piezoelectric elements is provided with a pair of arms 6 from a base 63.
Reference numerals 4 and 65 each include a piezoelectric element piece 62 having a tuning-fork type planar shape extending in parallel in the same direction. The piezoelectric element piece 62 is made of a quartz wafer. A plug 66 having two internal terminals 67 connected to the base 63 of the piezoelectric element piece 62 and a piezoelectric element piece 6
2 is housed in the case 6
8 and the plug 66 keep the inside at a low pressure. The plug 66 has an external terminal 69 extending on the opposite side.

As shown in FIG. 12, electrodes 73 and 74 are formed on the upper and lower surfaces of a piezoelectric element piece 62 of such a tuning-fork type crystal resonator, respectively, with a predetermined gap 75 therebetween. By applying an AC voltage to the electrodes 73 and 74 from the external terminals 69 of the plug 66 shown in FIG. 1, the pair of arms 64 and 65 of the piezoelectric element piece 62 vibrate at a predetermined frequency. As shown in FIG. 14E, the electrodes 73 and 74 have a two-layer structure of a base metal layer 91 made of chromium and an upper electrode layer 92 made of gold.

Here, in order to connect the electrode films 73 and 74 respectively formed on the upper and lower surfaces of the piezoelectric element piece 62, the electrodes 73 and 74 are also provided on the side end faces of the piezoelectric element piece 62.
74 are formed continuously. However, since it is necessary to insulate and separate the electrodes 73 and 74 also on the side end surfaces, a gap 77 is formed on the side end surface of the cross section 76 sandwiched between the base portions of the arms 64 and 65 on both sides.

[0005] Further, as shown in FIG.
The base 63 is formed with a mount 78 for connecting the internal terminals 67 by soldering. As shown in FIG. 13, an electrode film for connecting the electrodes 73 and 74 between the upper surface and the lower surface of the piezoelectric element piece 62 is also formed on the side end surface 81 on the base end side with respect to the base 63. In addition, on the side end face 81, the electrode film is divided by a gap 82 at the center in order to insulate and separate the electrodes 73 and 74.

A piezoelectric element constituting such a crystal resonator is manufactured by a manufacturing method shown in FIG. First, Figure 1
After the crystal wafer 85 cut out as shown in FIG. 4A is polished and washed, a light shielding layer 86 is formed as shown in FIG. 14B. Here, the chromium layer is formed by a sputtering method.

After a photoresist is applied on the light-shielding layer 86, the photoresist is exposed and developed into the shape of the piezoelectric element piece 62, that is, a tuning fork-shaped pattern, thereby forming a tuning fork-shaped resist mask 87. I do.
Thereafter, the portion of the light shielding layer 86 is formed into the same tuning fork shape as the resist mask by etching.

Next, the quartz wafer 85 is put into a mixed solution of hydrofluoric acid and ammonium fluoride using the light shielding layer 86 as a mask, and wet etching is performed. As a result, the quartz wafer is formed into a tuning fork shape as shown in FIG. 14D. This crystal piece becomes the piezoelectric element piece 62.

Next, the light shielding layer 86 on the piezoelectric element piece 62 is removed, and a chromium layer 91 and a gold layer 92 for forming the electrodes 73 and 74 are successively formed by sputtering in FIG.
It is formed as shown in FIG. Thereafter, a photoresist is applied to the surface of the gold layer 92 for forming the electrode films 73 and 74 by a spray method. And after this Figure 14
As shown in E, the photoresist is exposed and developed in the pattern of the electrodes 73 and 74 to form a resist mask 93 having the outer shape of the electrode films 73 and 74.

Thereafter, as shown in FIG. 14F, the gold layer 92 and the chromium layer 91 are etched through a resist mask 93, and the pattern of the two-layer electrode films 73 and 74 composed of the gold layer 92 and the chromium layer 91 is formed. Shape. Thus, the electrodes 73 and 74 composed of the base metal composed of the chromium film 91 and the gold electrode layer 92 are formed.

[0011]

In the process of manufacturing such a piezoelectric element, in particular, the chromium layer 91 and the gold layer 9 for forming the electrodes 73 and 74 in the metal film forming step.
In the mask forming step after the formation of 2, the photoresist is applied to the entire surface of the piezoelectric element piece 62 by a spray method. Then, after the assembly of the piezoelectric element pieces 62 is aligned with the glass mask, exposure and development are performed to form a resist mask 93.

However, according to the conventional method of processing a piezoelectric element by wet etching, one of the side end faces 84 of the arms 64 and 65 is easily melted due to the directionality of the crystal of the quartz wafer 85. Therefore, as shown in FIG. Become perpendicular to the end face. On the other hand, the other side end face 8
Reference numeral 3 denotes a tapered end surface inclined about 5 degrees with respect to the vertical direction.

Further, as shown in FIG. 16, a serrated portion 100 of the semiconductor element piece 62 has a serrated projection 100 at the center of the thickness of the piezoelectric element piece 62. For this reason, an oblique exposure technique is used for the photoresist applied to the side end surface of the portion 76 and the side end surface 81 of the base 63 (see FIG. 13) sandwiched between the base portions of the arms 64 and 65. However, there is a problem that the exposure accuracy is not sufficient and the gaps 77 and 82 having a sufficient width cannot be accurately formed. That is, as shown in FIG. 16, the illuminance of the ultraviolet light 101 may be insufficient in the portion 76, and the photoresist may not be removed by development. For this reason, there is a possibility that a short circuit occurs between the electrodes on such a side end surface, resulting in a defective product.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and more particularly, a piezoelectric element and a method of manufacturing the same, which more reliably prevent the occurrence of defective products due to defective photoresist formation on side end surfaces. The method and aims to provide.

[0015]

According to one aspect of the present invention, two electrode films are separately formed on the upper and lower surfaces of a piezoelectric element piece with a predetermined gap therebetween, and side end surfaces are formed over the entire circumference. The present invention relates to a piezoelectric element comprising one or a plurality of inclined surfaces protruding in the direction.

Here, the angle of the inclined surface of the side end surface may be 5 to 20 degrees with respect to the vertical direction of the upper surface or the lower surface.
Further, two inclined surfaces that intersect so as to protrude outward may be provided on the side end surface, and the intersection of the inclined surfaces may be an intermediate position in the thickness direction of the piezoelectric element piece.

The invention relating to a manufacturing method includes a mask forming step of forming a resist mask in a predetermined shape on a wafer made of a piezoelectric material, a piezoelectric element piece processing step of processing into a predetermined piezoelectric element piece shape using the resist mask. A metal film forming step of forming a metal film on the surface of the piezoelectric element piece, a mask forming step of forming an electrode resist mask on the surface of the metal film, and etching the metal film using the electrode resist mask. An electrode film forming step of forming two or more electrode films divided on the surface of the piezoelectric element piece so as to be separated by a predetermined gap. The solid-gas two-phase flow dispersed therein is jetted from a nozzle to reduce the thickness of the piezoelectric element wafer to 55-8.
The present invention relates to a method for manufacturing a piezoelectric element, characterized in that processing is performed to reach 0%, and then, a piezoelectric element wafer is inverted and a solid-gas two-phase flow in which an abrasive is dispersed in high-pressure air is jetted from a nozzle. .

The injection port of the nozzle for injecting the solid-gas two-phase flow has a rectangular shape whose long side is at least five times longer than the short side, and whose length in the axial direction is short side. The outlet of the acceleration chamber having a length of 20 times or more may be the injection port. In addition, a nozzle having a rectangular injection port may sequentially repeat scanning in the length direction of the piezoelectric element piece and pitch feeding in a direction perpendicular to the length direction of the piezoelectric element piece. The mask for processing the piezoelectric element piece may be made of a photosensitive polyurethane resin, and the post-baking temperature of the resist mask may be 80 to 180 ° C. Also, the piezoelectric material wafer on which the resist mask is formed is foamed by heat and attached to the foamed surface of the foamed peeling sheet having zero adhesive strength, and the foamed peeling sheet is fixed to a substrate such as glass to process the piezoelectric element pieces. You may do it. After the processing by jetting the solid-gas two-phase flow from the nozzle, the processing distortion of the piezoelectric element piece may be removed by wet etching.

[0019]

According to the invention relating to the manufacturing method, the processing step of the piezoelectric element piece is performed by injecting a solid-gas two-phase flow in which an abrasive is dispersed in high-pressure air from a nozzle to obtain 55 to 55 mm of the thickness of the piezoelectric element wafer.
Since the processing is performed until the pressure reaches 80%, the piezoelectric element wafer is turned over, and a solid-gas two-phase flow in which an abrasive is dispersed in high-pressure air is ejected from a nozzle. Has a plurality of inclined surfaces that intersect so as to protrude outward, and the position where such inclined surfaces intersect is an intermediate position in the thickness direction of the piezoelectric element piece.

Therefore, when a photoresist is applied to the entire outer surface of such a piezoelectric element piece and then exposed to form a resist at a predetermined position, the exposure accuracy is improved. Can be formed. Therefore, it is possible to accurately form the gap between the electrodes and the electrodes on the side end faces respectively connected to the electrodes on the upper and lower faces, thereby preventing the electrodes on the side end faces from being short-circuited and becoming defective.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION
A step of forming a piezoelectric element piece by injecting a solid-gas two-phase flow in which a fine abrasive is dispersed in high-pressure air, thereby forming a piezoelectric element piece; and forming a metal for forming an electrode film on the surface of such a piezoelectric element piece. A metal film forming step of forming a film, a mask forming step of forming a resist mask on the surface of such a metal film,
Patterning the metal film using the resist mask formed here, and forming two or more electrode films divided on the surface of the piezoelectric element piece with a predetermined gap therebetween. In the piezoelectric element piece forming step, a resist mask is formed on both sides of a quartz wafer, and a solid-gas two-phase flow in which a fine abrasive is dispersed in high-pressure air is sprayed from a nozzle onto the quartz wafer. Injection is performed on the surface to form a piezoelectric element piece.

In the method of manufacturing a piezoelectric element piece according to such a method, a powder beam processing method of injecting a solid-gas two-phase flow is employed when processing an outer shape into a predetermined shape of a piezoelectric element piece. In addition, it becomes possible to process the shape of the side end surface of the piezoelectric element into a tapered shape having an inclined surface that protrudes outward over the entire circumference. Further, since the powder beam processing method is a grinding process using an abrasive, unlike the etching using an etching solution such as hydrofluoric acid, maintenance of the processing conditions is simple and an exhaust gas treatment device is not required. Furthermore, the abrasive is harmless, and for dry processing,
Disposal or regeneration of used abrasives is facilitated.

Since the shape of the side end face of the processed piezoelectric element has a tapered shape that protrudes outward over the entire circumference, light is easily hit by the ultraviolet exposure of the resist forming the electrode. As a result, the electrode pattern on the side end face, particularly in the case of a tuning fork type quartz crystal resonator, can be surely patterned at the portion between the arms.

Since the quartz crystal wafer forming the piezoelectric element piece is bonded to the glass substrate with a foamed release sheet and then subjected to powder beam processing by a solid-gas two-phase flow, the quartz wafer is not damaged during the processing. In addition, it can be peeled off in about 20 seconds just by placing it on a heated hot plate, which brings about an advantage that replacement is easy.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. This embodiment shows a piezoelectric element composed of a tuning-fork type quartz resonator and a method of manufacturing the same. In describing the contents of this embodiment, parts common to the related art will be denoted by common reference numerals. FIG. 1 is common to the related art, so that the description will be made with common use.

FIG. 1 shows the overall structure of the piezoelectric element of the present embodiment.
2 is provided. The piezoelectric element piece 62 extends from the base 63 so that the first and second arms 64 and 65 extend in the same direction in parallel with each other, and has a tuning-fork type planar shape. That is, the piezoelectric element piece 62 made of a thin plate-like crystal piece is used. The base 6 of such a piezoelectric element piece 62
Two internal terminals 67 extend from the plug 66 and are connected to 3. And such a piezoelectric element piece 6
2 and a plug 66 are covered by a case 68,
The inside of the case 68 is maintained in a low pressure state by the case 68 and the plug 66.

As shown in FIG. 2, electrodes 73 and 7 are provided on the upper and lower surfaces of the piezoelectric element piece 62, respectively.
4 are formed. These electrodes 73 and 74 are divided from each other by a gap 75, and these electrodes 7
When an AC voltage is applied to the terminals 3 and 74 via the external terminal 69, the plug 66 and the internal terminal 67, respectively,
4, 65 vibrate at a predetermined frequency. Here, the electrodes 73 and 74 have a two-layer structure of a base metal made of a chromium film and a gold electrode layer as described later.

In the piezoelectric element piece 62, the electrodes 73, 74 also extend to the side end faces to connect the electrodes 73, 74 between the upper surface and the lower surface. Here, since it is necessary to insulate and separate the electrodes 73 and 74 at predetermined positions also on the side end surfaces, for example, a gap 77 is formed on the side end surface inside the side portion 76 sandwiched between the base portions of the arms 64 and 65. Is formed.

Here, as shown in FIGS. 2 and 3, each side end surface of the piezoelectric element piece 62 has an inclined surface having an inclination of 5 to 20 degrees with respect to a direction perpendicular to the upper or lower surface. It is formed so as to protrude outward so as to intersect with each other at the center in the thickness direction from the upper surface and the lower surface. For this reason, when forming a resist for forming the electrodes 73 and 74, the ultraviolet light 101 is irradiated directly above or at an angle of 0 to 30 degrees as shown in FIG. Can be reliably exposed.

For this reason, the gap 7 is also formed in the portion 76.
The resist does not remain over the entire width of 7, thereby making it possible to form the electrode patterns 73 and 74 with high accuracy. From this, the electrodes 73 and 74 can be accurately formed on the side end faces, particularly also on the portion 76,
The occurrence of a short circuit between the electrodes 73 and 74 is eliminated, and the product is not defective.

Here, if the angle of the inclined surface of the side end face of the piezoelectric element piece 62 is 5 degrees or less, the resist on the side end face is exposed to ultraviolet light 1.
01 cannot be reliably exposed. On the other hand, when the angle of the inclined surface is 20 degrees or more, reproducibility of the angle becomes difficult, and characteristics such as an equivalent resistance value deteriorate.

Next, a method of manufacturing the piezoelectric element piece 62 shown in FIG. 2 will be described with reference to FIG. Although this manufacturing process has some parts in common with the semiconductor manufacturing process, unlike the semiconductor manufacturing process, in the case of a quartz oscillator, it is necessary to perform each process on a piezoelectric element that is a three-dimensional member, Moreover, there is a special circumstance in which the same pattern is formed on both side surfaces of the crystal wafer 85. In FIG. 4,
A portion corresponding to the two arms 64 and 65 of the piezoelectric element piece 62 is shown in cross section.

First, as shown in FIG. 4A, a quartz wafer 85 cut out is polished and washed, and
A light shielding layer 86 is formed as shown in FIG. Note that, here, a chromium layer is formed by sputtering in order to serve also as formation of an electrode described later.

Next, after a sheet-like resist material is laminated on the surface of the light-shielding layer 86, the sheet resist is exposed to a pattern of the piezoelectric element, followed by development and drying. In order to further increase durability and adhesion, 80-1
Baking is performed at 80 ° C., thereby forming a resist mask 87 having a piezoelectric element outer shape on the quartz wafer 85 as shown in FIG. 4B.

Thereafter, as shown in FIG. 6, a quartz wafer 85 having a resist mask 87 having an outer shape of the piezoelectric element piece 62 formed on both sides is attached to the surface of the foam release sheet 96. In addition, the adhesive surface of the foam release sheet 96 is attached to a substrate 97 made of soda glass in advance.

Then, a solid-gas two-phase flow in which abrasives of GC # 600-3000 are dispersed in high-pressure air is jetted to the quartz wafer 85 by the nozzle 12. Here, since the crystal wafer 85 is a very brittle material,
The impact force during processing must be as small as possible. For this reason, the shape of the injection port of the nozzle 12 is such that the short side t of the injection port 57 is 0.3 mm as shown in FIGS.
And the long side w is at least 5 times the
The rectangular nozzle 12 has a length of 0 to 50 mm, and the length h of the abrasive processing chamber 56 in the axial direction is 20 times or more the short side.

As shown in FIG. 6, the rectangular nozzle 12 scans the quartz wafer 85 in parallel with the length direction of the piezoelectric element, and then performs further scanning after pitch feeding.
This is sequentially repeated, whereby the entire surface of the quartz wafer 85 is processed. Processing depth is crystal wafer 85
The processing is completed at 55 to 85% of the thickness of.

When the processing depth of the quartz wafer by the scanning of the nozzle 12 is 55% or less, the penetrating processing is not realized, or a disturbed shape at the initial stage of the penetrating remains, whereby a stable shape is obtained. May not be available. If the processing depth is 80% or more, the material penetrates in the first processing, and the impact at this time causes large chipping, which causes deterioration of the characteristics of the piezoelectric element.

When the nozzle 12 is scanned while the gas-solid two-phase flow is being jetted to polish one surface of the quartz wafer 85, the processing is thereafter stopped, and the front and back of the quartz wafer 85 are turned over to form a foam release sheet. 96, and the opposite surface is processed the same number of times or for the same time. If the number of scans is different on both sides of the quartz wafer 85, FIG.
The position in the thickness direction of the apex where the inclined surfaces of the side end surfaces intersect with each other is not constant, which causes variation in the piezoelectric characteristics.

Next, an example of processing by such a solid-gas two-phase flow will be described below.

Abrasive material: GC # 1000 Air flow rate: 400 Nl / min Scan speed: 400 mm / sec The processed quartz wafer 85 is placed on a heated hot plate and peeled off from the foam release sheet 96. Next, such a crystal wafer 85 is placed in an etching solution such as hydrofluoric acid, thereby removing processing distortion. In this way, a piezoelectric element piece made of quartz as shown in FIG. 4C is obtained.

Next, the resist mask 87 and the light shielding layer 86 remaining on the piezoelectric element piece 62 are all removed, and FIG.
As shown in D, a chromium layer 91 and a gold layer 92 for forming an electrode film are formed. Although not shown, the weight portion for frequency adjustment is connected to the arm 6 of the piezoelectric element piece 62.
4, 65 are formed as gold films on the tip side.

Next, a photoresist is applied to the surface of the gold layer 92 by a spray method, and then, as shown in FIG. 4D, a photoresist 93 is exposed and developed in a pattern of each of the electrodes 73 and 74. A resist mask 93 corresponding to the shape of 74 is formed.

Thereafter, as shown in FIG. 4E, the gold layer 92 and the chromium layer 9 are formed using this resist mask 93.
1 is etched. Then, the gold layer 92 and the chrome layer 9
One gap portion is removed by etching, and a pattern of the electrodes 73 and 74 is formed. Thus, it is possible to form the electrodes 73 and 74 composed of the base metal layer 91 composed of the chromium layer and the gold electrode layer 92. Thereafter, the resist mask 93 is removed.

Next, referring to FIG. 5, the overall structure of a powder and particle jet processing apparatus for forming such a piezoelectric element piece 62 by etching from a quartz wafer 85 by powder beam processing will be described. The nozzle 12 used at this time will be described with reference to FIGS.

FIG. 5 shows the overall configuration of a powder and particle blast processing apparatus suitable for performing the processing according to this embodiment.
This apparatus has a processing chamber 10. A work 11 is held in the processing chamber 10 via a work holder 50, and the nozzle 12 is opposed to the work holder 50.
Is arranged. The nozzle 12 is scanned by an actuator 14 via an arm 13. The wall of the processing chamber 10 through which the arm 13 passes is sealed by the bellows 15.

The bottom of the processing chamber 10 is connected to a separation device 20 via a pipe 19. The separation device 20 includes a filter 21, and the filter 21 separates air and powder. The air separated by the filter 21 is discharged to the upper part, and the collected powders are stored and used repeatedly.

An opening / closing valve 24 is provided at a lower portion of the separation device 20, and is connected to the intermediate tank 25 via the opening / closing valve 24. The intermediate tank 25 is provided with a screw conveyor 26 at the bottom thereof, and pushes the powder particles accumulated at the bottom of the intermediate tank 25 rightward in FIG.

The bottom of the intermediate tank 25 is connected to a supply tank 32 via a connection tube 30. A conical valve 31 is provided at the bottom of the connecting cylinder 30 and at a portion connected to the supply tank 32, and the supply of the granular material from the intermediate tank 25 to the supply tank 32 is controlled by the conical valve 31. I have to.

In the supply tank 32, a stirring rod 33 and a screw conveyor 34 are vertically arranged. The stirring rod 33 and the screw conveyor 34 are respectively connected to the motor 3
5 and 36 are driven to rotate.

The apparatus further comprises an air pressure source 40, to which a dry unit 41, a flow sensor 42, a flow controller 43, and a branch unit 44 are connected in series. One branch pipe of the branch unit 44 is connected to the mixing pipe 45. And this mixing tube 4
5 is connected to the ejector 46. The ejector 46 sucks the air flow containing the powdery material from the mixing pipe 45 and supplies the air flow to the nozzle 12 in the processing chamber 10.

Next, the outline of the operation of such a granular material jet processing apparatus will be described. The high-pressure air supplied from the air pressure source 40 is supplied to a lower portion of the mixing pipe 45 through a dry unit 41, a flow sensor 42, a flow control unit 43, and a branch unit 44. The high-pressure air flowing through the mixing pipe 45 sucks the powder and the granular material extruded from the supply hole 47 at the bottom of the supply tank 32 and supplies the powder to the ejector 46. In the ejector 46, the granular material is mixed into the high-pressure air supplied from the branch unit 44, whereby a solid-gas two-phase flow is generated. Such a solid-gas two-phase flow is supplied to the nozzle 12 in the processing chamber 10.

The nozzle 12 has a slit-shaped injection port on the tip side, and the nozzle 1 has a work 1 on the work holder 50.
Arm 1 by actuator 14 along the surface of
The surface of the work 11 is processed while scanning through the work 3. That is, a solid-gas two-phase flow of high-pressure air and granular material is vigorously blown from the injection port of the nozzle 12 onto the surface of the work 11, thereby performing the granular material injection processing.

The processed mixture of the granular material and air is led to the separation device 20 through the pipe 19. The air and the powder are separated by the filter 21 in the separation device 20, and the air is discharged from the upper portion of the separation device 20 to the outside. A part of the air is supplied into the processing chamber 10, the air is rectified in the processing chamber 10, and the flow of the solid-gas two-phase flow of the granular material and the air from the nozzle 12 is rectified. ing. Further, some air is stored in the intermediate tank 25.
And the pressure in the intermediate tank 25 is increased.

The granular material separated by the separating device 20 falls into the intermediate tank 25 as the on-off valve 24 opens. When the screw conveyor 26 is driven, the intermediate tank 2
5 accumulates in the supply tank 32 in synchronization with the opening of the conical valve 31 of the connection cylinder 30. The granular material in the supply tank 32 is stirred by the stirring rod 33. When the screw conveyor 34 is driven by the motor 36 below the stirring rod 33, the powder particles accumulated at the bottom of the supply tank 32 are sequentially supplied from the supply holes 47 to the mixing pipe 45. In this way, the granules are repeatedly used many times.

Next, the nozzle 12 used in such a processing apparatus will be described with reference to FIGS. The nozzle 12 includes an abrasive dispersion chamber 54 in which a powder or a granular material supplied by high-pressure air is supplied from an abrasive inlet 53, an abrasive collection chamber 55 for collecting the abrasive, and polishing for accelerating the abrasive. A material accelerating chamber 56 is provided, and an injection port 57 on the tip side of the acceleration chamber 56 is provided. The injection port 57 is used to jet the abrasive.

Therefore, the nozzle 1 carried by the high pressure air
The abrasive supplied into the nozzle 2 through the abrasive inlet 53 is spread over the entire internal space of the nozzle 12 by the abrasive dispersion chamber 54, is then collected linearly by the focusing chamber 55, and then accelerates downstream. It is supplied to the chamber 56. In the acceleration chamber 56, the flow rate of the solid-gas two-phase flow is maximized, and the direction of the abrasive is aligned parallel to the axial direction of the acceleration chamber 56 simultaneously with acceleration. That is, the abrasive is ejected from the ejection port 57 of the nozzle 12 as a straight parallel flow.

When the crystal wafer 85 is processed by the apparatus shown in FIG. 5 using the nozzles 12 shown in FIGS. 7 to 9, the portion where the resist mask 87 is not formed is shown in FIG.
It is removed as shown in FIG. At this time, the nozzle 12
Of the solid-gas two-layer jet flow injected from the injection port 57 of this embodiment forms a concave portion having an arc-shaped cross section. At this time, the abrasive that comes out of the nozzle 12 and hits the bottom of the concave portion polishes this portion and rebounds, and flows along the length direction of the concave portion. On the other hand, the abrasive material that hits the side surface of the concave portion polishes this portion and bounces off. As a result, the amount of grinding at the central portion of the concave portion increases, whereas the amount of grinding at the both end portions decreases. Therefore, when such processing is performed,
The side end surface of the piezoelectric element piece 62 formed by the quartz wafer 85 is an inclined surface.

For this reason, as shown in FIG. 11, after the crystal wafer 85 has been processed to 55 to 80% of the thickness direction, and this quartz wafer 85 is turned upside down and sprayed again by the nozzle 12, the side end surface becomes A shape having two inclined surfaces protruding to the outer peripheral side at a substantially central portion in a thickness direction thereof is obtained, whereby a piezoelectric element piece 62 as shown in FIG. 2 is obtained.

Since such a piezoelectric element piece 62 has a shape in which all side end surfaces have two inclined surfaces such that a substantially central portion in the thickness direction projects outward. When the electrodes 73 and 74 are formed by applying a resist mask for forming the electrodes 73 and 74 and then performing exposure, it is possible to form an accurate pattern even on the side end surfaces. Therefore, accurate electrode patterns 73 and 74 are formed also on the side end faces, and inconveniences such as short-circuiting especially at the side end faces do not occur, thereby greatly reducing defective products.

[0061]

As described above, according to one aspect of the present invention, two electrode films are formed separately on the upper and lower surfaces of the piezoelectric element piece with a predetermined gap therebetween, and the side end surfaces are formed over the entire circumference. It comprises one or a plurality of inclined surfaces protruding in the direction.

Therefore, according to such a piezoelectric element, its side end surface is constituted by one or a plurality of inclined surfaces which protrude outward over the entire circumference. In addition, it is possible to accurately form an electrode pattern on the side end face, and short-circuiting and disconnection due to electrode failure at the side end face portion are prevented, thereby preventing occurrence of defective products.

The invention relating to the manufacturing method includes a mask forming step of forming a resist mask in a predetermined shape on a piezoelectric material wafer, a piezoelectric element piece processing step of processing the piezoelectric element piece into a predetermined shape using the resist mask, A metal film forming step of forming a metal film on the surface of the piezoelectric element piece, and a mask forming step of forming an electrode resist mask on the surface of the metal film,
An electrode film forming step of etching the metal film using an electrode resist mask to form two or more electrode films divided on the surface of the piezoelectric element piece with a predetermined gap therebetween;
And a piezoelectric element piece processing step, in which a solid-gas two-phase flow in which an abrasive is dispersed in high-pressure air is jetted from a nozzle to process 55 to 80% of the thickness of the piezoelectric element wafer,
Next, the piezoelectric element wafer is inverted, and a solid-gas two-phase flow in which an abrasive is dispersed in high-pressure air is ejected from a nozzle.

Therefore, according to such a manufacturing method, it is possible to efficiently manufacture a piezoelectric element having one or a plurality of inclined surfaces whose side end surfaces protrude outward over the entire circumference. .

[Brief description of the drawings]

FIG. 1 is a partially broken perspective view showing the entire configuration of a tuning fork type crystal resonator.

FIG. 2 is an external perspective view of a piezoelectric element piece of the crystal unit.

FIG. 3 is an enlarged perspective view of the main part.

FIG. 4 is a longitudinal sectional view illustrating a manufacturing process of the piezoelectric element piece.

FIG. 5 is a block diagram showing the overall configuration of the injection processing apparatus.

FIG. 6 is a perspective view of a main part showing injection processing by a nozzle.

FIG. 7 is a perspective view of a nozzle.

FIG. 8 is a longitudinal sectional view of a nozzle.

9 is a longitudinal sectional view of the nozzle in a direction different from that of FIG. 8 by 90 degrees.

FIG. 10 is a longitudinal sectional view showing an etching process of a quartz wafer by a solid-gas two-phase flow.

FIG. 11 is a longitudinal sectional view showing an etching process of a quartz wafer by a solid-gas two-phase flow.

FIG. 12 is an external perspective view of a conventional piezoelectric element piece.

FIG. 13 is a front view of a side end surface of the piezoelectric element piece.

FIG. 14 is a longitudinal sectional view illustrating a manufacturing process of the piezoelectric element piece.

FIG. 15 is an external perspective view showing a state where a resist mask is formed on a piezoelectric element piece.

FIG. 16 is an enlarged perspective view of the main part.

[Explanation of symbols]

10 mm processing room, 11 mm workpiece (workpiece), 12 mm
{Nozzle, 13} Arm, 14} Actuator,
15 ‥‥ bellows, 19 ‥‥ conduit, 20 ‥‥ separator, 21
‥‥ Filter, 24 ‥‥ open / close valve, 25 ‥‥ intermediate tank,
26 ‥‥ screw conveyor, 30 ‥‥ connection cylinder, 31 ‥‥
Conical valve, 32 ‥‥ supply tank, 33 ‥‥ stirring rod, 34 ‥
‥ Screw conveyor, 35, 36 ‥‥ Motor, 40 ‥‥
Air pressure source, 41 ‥‥ dry unit, 42 ‥‥ flow sensor, 43 ‥‥ flow control unit, 44 ‥‥ branch unit, 45
{Mixing tube, 46} Ejector, 47} Supply hole, 51
{Housing, 52} Nozzle tip, 53} Abrasive inlet, 54 {Abrasive dispersion chamber, 55} Abrasive concentrating chamber, 56 {Abrasive accelerating chamber, 57} Injector, 58}
O-ring, 62 ‥‥ piezoelectric element piece, 63 ‥‥ base, 64,
65mm arm, 66mm plug, 67mm internal terminal,
68 ‥‥ case, 69 ‥‥ external terminal, 73, 74 ‥‥ electrode, 75 ‥‥ gap, 76 ‥‥ cross section, 77 ‥‥ gap, 78 ‥‥ mount part, 79 ‥‥ end face, 81 ‥‥ side end face , 82 ° gap, 83, 84 ° side end face, 85 °
{Quartz wafer, 86} Chromium layer (light shielding layer), 87}
{Resist mask (photosensitive urethane), 91} Chrome layer, 92} Gold layer, 93} Resist mask, 96}
Foam release sheet, 97 ‥‥ soda glass substrate, 100 ‥
{Jagged protrusion, 101} Ultraviolet light

Claims (9)

[Claims] An electrode film is divided and formed on upper and lower surfaces of a piezoelectric element piece with a predetermined gap therebetween.
The piezoelectric element is characterized in that the side end surface is constituted by one or a plurality of inclined surfaces protruding outward over the entire circumference. 2. The piezoelectric element according to claim 1, wherein the angle of the inclined surface of the side end surface is 5 to 20 degrees with respect to the vertical direction of the upper surface or the lower surface. 3. A side end face having two inclined surfaces intersecting so as to protrude outward, and a position where the inclined surfaces intersect is an intermediate position in a thickness direction of the piezoelectric element piece. The piezoelectric element according to claim 1, wherein: 4. A mask forming step of forming a resist mask in a predetermined shape on a wafer made of piezoelectric material, a piezoelectric element piece processing step of processing into a predetermined shape of a piezoelectric element piece using the resist mask, Forming a metal film on the surface of the metal film, forming a resist mask for the electrode on the surface of the metal film, etching the metal film using the resist mask for the electrode, the piezoelectric element An electrode film forming step of forming two or more electrode films divided so as to separate a predetermined gap on the surface of the piece, wherein the piezoelectric element piece processing step disperses the abrasive in high-pressure air. The solid-gas two-phase flow was jetted from a nozzle to process until the thickness of the piezoelectric element wafer reached 55 to 80%, and then the piezoelectric element wafer was inverted to disperse the abrasive in high-pressure air. Method for manufacturing a piezoelectric element characterized by injecting the gas two-phase flow from the nozzle. 5. An injection port of a nozzle for injecting a solid-gas two-phase flow,
The outlet of the acceleration chamber having a rectangular shape whose long side is at least 5 times longer than the short side and whose axial length is at least 20 times longer than the short side is the injection port. The method for manufacturing a piezoelectric element according to claim 4, wherein 6. A nozzle having a rectangular injection port sequentially repeats scanning in the length direction of the piezoelectric element piece and pitch feeding in a direction perpendicular to the length direction of the piezoelectric element piece. Item 5. The method for manufacturing a piezoelectric element according to Item 4. 7. The piezoelectric element according to claim 4, wherein the mask for processing the piezoelectric element piece is made of a photosensitive polyurethane resin, and the resist mask has a post-baking temperature of 80 to 180 ° C. Production method. 8. A piezoelectric element, wherein a wafer of a piezoelectric material on which a resist mask is formed is foamed by heat and adhered to a foamed surface of a foamed peeling sheet having an adhesive strength of zero, and the foamed peeling sheet is fixed to a substrate such as glass to form a piezoelectric element. The method for manufacturing a piezoelectric element according to claim 4, wherein the piece is processed. 9. The method for manufacturing a piezoelectric element according to claim 4, wherein the processing distortion of the piezoelectric element piece is removed by wet etching after processing by jetting a solid-gas two-phase flow from a nozzle.