JP2009088753A - Method of manufacturing piezoelectric vibrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a piezoelectric vibrator having good characteristics, which can perform patterning of a photoresist layer precisely. <P>SOLUTION: Since patterning of a photoresist layer is performed in separate steps for the front surface side and the back surface side of a crystal substrate, and a photoresist layer formed on the other side of the crystal substrate is heat-treated before a photoresist layer formed on one side is developed, the photoresist layer formed on the other side is not eroded with developing solution for developing the photoresist layer on one side and a piezoelectric vibrator having good characteristics can be obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a piezoelectric vibrator made of a vibrating piece such as quartz.

  In recent years, vibrators that are used as time standards for electronic devices are required to have a small vibrator size and a small CI value as the electronic equipment in which they are used is downsized. For example, in the case of a tuning-fork type crystal resonator, there has been conventionally known a structure configured as shown in FIGS. 9A and 9B (for example, Patent Document 1).

  Here, FIG. 9A is a top view of the tuning fork type crystal resonator, and FIG. 9B is a cross-sectional view taken along line AA of FIG. 9A. The tuning fork type crystal resonator 11 has two legs 12, and groove portions 13 each having a long groove are formed on the front and back surfaces of each leg 12. As shown in FIG. The cross-sectional shape is substantially H-shaped. Here, since the tuning fork type crystal resonator having a substantially H-shaped cross section can increase the electromechanical conversion coefficient even if the size of the resonator is smaller than the conventional size, the CI value (crystal impedance or Equivalent series resistance) can be kept low.

  As a manufacturing method of a crystal resonator in which a groove is formed like the substantially H-shaped tuning fork crystal resonator, for example, a manufacturing method of Patent Document 1 is proposed. In Patent Document 1, an inverted mesa AT-cut quartz crystal resonator element is used as an embodiment, but here, a manufacturing method in the case where it is applied to a tuning fork crystal resonator will be described.

  10 to 12 are views showing a conventional manufacturing method of a tuning fork type crystal resonator in which the cross section of the vibration leg portion is substantially H-shaped. In FIG. 10, first, a quartz substrate 101 is prepared (FIG. 10A). Next, a metal film composed of a Cr film 102 and an Au film 103 is formed on both the front and back surfaces of the quartz substrate 101 by vapor deposition or sputtering (FIG. 10B). Next, a photoresist is applied to the surface of the metal film to form a photoresist layer 104 (FIG. 10C). Next, the outer shape of the tuning fork crystal resonator is exposed and developed using a photomask, and patterned so that the photoresist layer 104 remains inside the outer shape of the tuning fork crystal resonator, thereby exposing the outer metal film ( FIG. 10 (d)). Next, the exposed metal film is removed by etching in the order of the Au film 103 and the Cr film 102 (FIG. 11A). Subsequently, the remaining photoresist layer 104 is exposed and developed again with a photomask using a photomask to expose the metal film in the groove (FIG. 11B). Next, the exposed quartz substrate 101 is etched with an etching solution for crystal etching. As a result of the etching, the outer shape of the tuning fork type crystal resonator is formed (FIG. 11C). Subsequently, the metal film is etched using the remaining photoresist layer 104 as a mask, and the metal film exposed in the groove is removed in the order of the Au film 103 and the Cr film 102 (FIG. 11D). Next, the quartz substrate 101 exposed corresponding to the groove is etched by a predetermined depth with an etching solution for crystal etching to form the groove 105 (FIG. 12A). The remaining photoresist layer 104 and the metal film are removed to complete the shape of a substantially H-shaped tuning fork crystal resonator (FIG. 12B). Thereafter, a drive electrode is formed on the surface of the tuning fork type crystal resonator, thereby completing a substantially H type tuning fork type crystal resonator.

In the above manufacturing method, when the photoresist layer is exposed to the etching solution for the metal film, the surface of the photoresist layer is altered and the exposure sensitivity is lowered, resulting in a surface altered layer that is not dissolved by normal exposure and development. For this reason, when exposing the groove portion, the exposure time is lengthened, the surface altered layer is removed with an alkaline solution such as a developer before the groove portion is exposed, and before or after the exposure of the groove portion. Patent Document 1 proposes that the surface-affected layer is removed by dry etching using oxygen plasma before the development.
Further, Patent Document 2 proposes a manufacturing method of a substantially H-type quartz crystal resonator in which the same photoresist layer is patterned a plurality of times without generating the above-mentioned surface altered layer.

JP 2002-261557 A JP 2006-86925 A

In the conventional crystal resonator manufacturing method disclosed in Patent Document 1 and Patent Document 2, a photoresist layer formed on a crystal substrate is exposed to both the front and back surfaces of the crystal substrate at the same time. And a manufacturing method for patterning a groove. In general, a projection exposure apparatus is used for patterning the photoresist layer, and this pattern is transferred to the photoresist layer through a projection lens provided in the projection exposure apparatus. As in the above conventional example, when transferring patterns to both sides of the photoresist layer on both sides of the quartz substrate at the same time, the projection lens of the projection exposure apparatus uses two projection lenses corresponding to the front and back sides of the quartz substrate. However, each projection lens has individual differences, and if the front and back surfaces of the quartz substrate are patterned simultaneously, they are transferred to the photoresist layer on the front and back surfaces due to individual differences between the projection lens for the front surface and the projection lens for the back surface. There arises a problem that a shift of a micron unit occurs in a pattern to be generated.
If the crystal resonator is manufactured in such a state where there is a pattern shift, the crystal resonator cannot be manufactured with high accuracy, and the electrical characteristics of the finished crystal resonator deteriorate.

  In addition, as the exposure process in the case of patterning on both sides of the substrate, the double-sided exposure in which the front and back surfaces of the substrate are simultaneously exposed and patterned as in the conventional technique described above, and the other side after exposing and patterning one side of the substrate Two methods of exposing and patterning the surface of the substrate and performing single-sided exposure on the front and back surfaces of the substrate are widely used. The problem like this occurs. When single-sided exposure is performed for each of the front and back surfaces, the crystal oscillator outline and groove pattern are formed on the photoresist layer formed on one surface, and then the crystal oscillator outline and groove pattern are formed on the other surface. However, during the development of the pattern on the other surface, the already patterned photoresist layer formed on one surface is exposed to the developer. Even if the photoresist layer is not exposed to light, it may be eroded by the developer when exposed to the developer multiple times. It was difficult. The present invention is to solve such problems, and to provide a method for manufacturing a piezoelectric vibrator that can perform patterning of a photoresist layer with high accuracy and has good characteristics.

In the method of manufacturing a piezoelectric vibrator made of a piezoelectric material and having a groove,
Forming a first metal film comprising a base layer and a surface layer on both surfaces of a piezoelectric substrate made of a piezoelectric material;
Applying a photoresist on one surface layer of the first metal film to form a first photoresist layer;
Applying a photoresist on the other surface layer of the first metal film to form a second photoresist layer;
Exposing and developing the first photoresist layer and patterning the outer shape of the piezoelectric vibrator to form a first resist pattern;
Removing the surface layer of the first metal film by etching using the first resist pattern as an etching mask;
Exposing and developing the first resist pattern and patterning the outer shape of the groove of the piezoelectric vibrator to form a second resist pattern;
Exposing and developing the second photoresist layer and patterning the outer shape of the piezoelectric vibrator to form a third resist pattern;
Removing the surface layer of the second metal film by etching using the third resist pattern as an etching mask;
Exposing and developing the third resist pattern and patterning the outer shape of the groove of the piezoelectric vibrator to form a fourth resist pattern;
Using the second resist pattern and the fourth resist pattern, the surface layer of the first metal film and the surface layer of the second metal film as an etching mask, the first metal film and the second metal film Removing the base layer of the metal film by etching, exposing the surface of the piezoelectric substrate other than the position corresponding to the outer shape of the piezoelectric vibrator; and
Removing the piezoelectric substrate exposed up to the previous step by etching;
Using the second resist pattern and the fourth resist pattern as an etching mask, the first metal film and the second metal film are removed by etching, and the piezoelectric substrate at a position corresponding to the groove portion of the piezoelectric vibrator A step of exposing
A step of removing a certain amount of the piezoelectric substrate corresponding to the groove portion of the piezoelectric substrate by etching to form a groove portion,
A method of manufacturing a piezoelectric vibrator comprising a step of heat-treating the second resist pattern after the step of forming the second resist pattern and before development in the step of forming the third resist pattern And

In the method of manufacturing a piezoelectric vibrator made of a piezoelectric material and having a groove,
Forming a first metal film comprising a base layer and a surface layer on one surface of a piezoelectric substrate made of a piezoelectric material;
Applying a photoresist on the surface layer of the first metal film to form a first photoresist layer;
Exposing and developing the first photoresist layer and patterning the outer shape of the piezoelectric vibrator to form a first resist pattern;
Removing the surface layer of the first metal film by etching using the first resist pattern as an etching mask;
Exposing and developing the first resist pattern and patterning the outer shape of the groove of the piezoelectric vibrator to form a second resist pattern;
Forming a second metal film comprising a base layer and a surface layer on the other surface of the piezoelectric substrate;
Applying a photoresist on the surface layer of the second metal film to form a second photoresist layer;
Exposing and developing the second photoresist layer and patterning the outer shape of the piezoelectric vibrator to form a third resist pattern;
Removing the surface layer of the second metal film by etching using the third resist pattern as an etching mask;
Exposing and developing the third resist pattern and patterning the outer shape of the groove of the piezoelectric vibrator to form a fourth resist pattern;
Using the second resist pattern and the fourth resist pattern, the surface layer of the first metal film and the surface layer of the second metal film as an etching mask, the first metal film and the second metal film Removing the base layer of the metal film by etching, exposing the surface of the piezoelectric substrate other than the position corresponding to the outer shape of the piezoelectric vibrator; and
Removing the piezoelectric substrate exposed up to the previous step by etching;
Using the second resist pattern and the fourth resist pattern as an etching mask, the first metal film and the second metal film are removed by etching, and the piezoelectric substrate at a position corresponding to the groove portion of the piezoelectric vibrator A step of exposing
A step of removing a certain amount of the piezoelectric substrate corresponding to the groove portion of the piezoelectric substrate by etching to form a groove portion,
A method of manufacturing a piezoelectric vibrator comprising a step of heat-treating the second resist pattern after the step of forming the second resist pattern and before development in the step of forming the third resist pattern And

  A method of manufacturing a piezoelectric vibrator in which the surface layer of the metal film is gold and the base layer is chromium.

  By patterning the photoresist layer formed on the quartz substrate in separate steps on the front and back sides, it becomes possible to pattern the external shape of the crystal resonator and the shape of the groove with high precision, and have a groove. In the piezoelectric vibrator manufacturing method, when patterning the outer shape of the piezoelectric vibrator and the shape of the groove is performed with the same photoresist layer, and patterning on the front side and the back side is performed in separate steps, Before developing the photoresist layer, the photoresist layer formed on the other surface is heat-treated so that the photoresist layer formed on the other surface develops the photoresist layer on one surface. The piezoelectric vibrator can be manufactured with high accuracy without being eroded by the developer, and a piezoelectric vibrator with good characteristics can be obtained.

  The best mode for carrying out the present invention will be described below with reference to the drawings. 1-5 is a figure which shows the manufacturing method of the piezoelectric vibrator of this invention. The piezoelectric vibrator manufacturing method of this embodiment will be described as an example of manufacturing the tuning fork type crystal vibrator shown in FIG.

  First, a Cr film 2 or 5 is deposited as a base metal film on the surfaces of both sides of the quartz substrate 1 processed into a plate shape by vapor deposition or sputtering to a thickness of about 250 mm, followed by Au as a surface metal film. The films 3 and 6 are stacked to form a film of about 1200 mm (FIG. 1A). The Cr films 2 and 5 act as an intermediate layer that improves the adhesion between the Au films 3 and 6 and the quartz substrate 1. The Au films 3 and 6 function as a corrosion-resistant film against a mixed solution of hydrofluoric acid and an ammonium fluoride solution used when the crystal is etched later.

Next, a photoresist is applied to the surfaces of the Au films 3 and 6 and dried to form photoresist layers 4 and 7 (FIG. 1B). As the photoresist, for example, S1800 (registered trademark) manufactured by Rohm and Haas Electronic Materials Co., Ltd., which is a positive photoresist, is used. Next, the photoresist layer 4 is exposed using a photomask for forming the outer shape of the tuning fork type crystal resonator (FIG. 1C). This is performed using a proximity exposure apparatus having a back surface alignment function. Then, the exposed photoresist layer 4 is developed so that the photoresist layer 4 remains only inside the outer shape of the tuning fork crystal unit (FIG. 1D).
Next, the Au film 3 is removed by etching (FIG. 2A). For etching the Au film 3, for example, an etching solution in which iodine is dissolved in a potassium iodide solution is used. Subsequently, the groove portion is exposed to the remaining photoresist layer 4 (FIG. 2B) and developed to remove the portion of the photoresist layer 4 corresponding to the groove portion (FIG. 2C). ).

  Next, the photoresist layer 7 is exposed using a photomask for forming the outer shape of the tuning fork crystal unit (FIG. 2D). Subsequently, the photoresist film 4 is heat-treated (not shown) without developing the photoresist layer 7 on the back side. The heat treatment is performed at 90 ° C. or more for 10 minutes or more by placing the quartz substrate 1 in a drying furnace. This heat treatment removes the developer, rinse solution, and moisture remaining in the photoresist 4 and improves the adhesion between the resist film 4 and the Au film 3, and resistance to the developer in the development of the resist film 7 performed in the next step. The purpose is to improve. Therefore, this process may be performed after the outer shape of the vibrator and the groove pattern are formed on the photoresist layer 4 on the front surface side and before the development of the photoresist layer 7 formed on the back surface side. In the embodiment, the process may be performed after the process of FIG. 2C and before the process of FIG.

  Next, the photoresist layer 7 is developed so that the photoresist layer 7 remains only inside the outer shape of the tuning fork crystal unit (FIG. 3A). Next, the Au film 6 is removed by etching (FIG. 3B). For etching the Au film 6, for example, an etching solution in which iodine is dissolved in a potassium iodide solution is used. Next, the groove portion is exposed to the remaining back surface side photoresist layer 7 (FIG. 3C), developed, and the photoresist layer 7 corresponding to the groove portion is removed (FIG. 3). (D)). Next, the Cr films 2 and 5 on the front surface side and the back surface side are etched and removed (FIG. 4A). For the etching, for example, an etching solution containing cerium ammonium nitrate is used.

  Next, the exposed quartz substrate 1 is etched using a mixed solution of hydrofluoric acid and ammonium fluoride to form the outer shape of the tuning fork type crystal resonator (FIG. 4B). Subsequently, the Au films 3 and 6 and the Cr films 2 and 5 exposed in the groove are removed by etching (FIG. 4C). Thereafter, using a mixed solution of hydrofluoric acid and ammonium fluoride, the exposed quartz substrate 1 corresponding to the groove is etched to process grooves (recesses) having a predetermined depth on both upper and lower surfaces (FIG. 5A). ). Finally, the photoresist layers 4 and 7, the Au films 3 and 6, and the Cr films 2 and 5 are removed to obtain the outer shape of a tuning fork type crystal resonator having a substantially H-shaped cross section (FIG. 5B). Although the example in which the photoresist layers 4 and 7 are removed after the groove etching process (FIG. 5A) is shown here, the photoresist layers 4 and 7 may be removed before the groove etching process. . Through the above steps, a substantially H-shaped tuning fork type crystal resonator as shown in FIG. 9 is completed. In addition, as a process of forming the drive electrode on such a tuning fork type crystal resonator, a conventional technique as disclosed in, for example, Patent Document 2 may be used.

As described above, by performing patterning on the photoresist layer formed on the quartz substrate using the proximity exposure apparatus having the back surface alignment function in separate steps on the front surface side and the back surface side, Patterning can be performed with the same optical system. Therefore, it is possible to pattern the outer shape of the crystal resonator and the shape of the groove with high accuracy without considering the optical system variation of the exposure apparatus.
Further, like the substantially H-shaped tuning fork type crystal resonator of the embodiment of the present invention, the patterning of the outer shape and the groove shape is performed with the same photoresist layer, and the patterning on the front side and the back side is performed in different steps. If the photoresist layer formed on the other surface is heat-treated before developing the photoresist layer on one surface, the photoresist layer formed on the other surface is The quartz crystal unit can be manufactured with high accuracy without being eroded by the developer for developing the photoresist layer.

  Next, another embodiment of the present invention will be described. 6 to 8 are views showing a method for manufacturing a piezoelectric vibrator of the present invention. The method for manufacturing the piezoelectric vibrator of this embodiment will be described as an example of manufacturing the tuning fork type crystal vibrator shown in FIG. The same members as those in the first embodiment will be described using the same reference numerals.

  First, a Cr film 2 having a thickness of about 250 mm is formed on one surface of the crystal substrate 1 processed into a plate shape (hereinafter, this surface is referred to as the surface side of the crystal substrate 1) as a metal film of an underlayer by vapor deposition or sputtering. Subsequently, an Au film 3 is laminated on the surface layer as a metal film of about 1200 mm to form a film (FIG. 6A). The Cr film 2 acts as an intermediate layer that improves the adhesion between the Au film 3 and the quartz substrate 1. The Au film 3 functions as a corrosion resistant film against a mixed solution of hydrofluoric acid and an ammonium fluoride solution used when etching the crystal later.

Next, a photoresist is applied to the surface of the Au film 3 and dried to form a photoresist layer 4 (FIG. 6B). As the photoresist, for example, S1800 (registered trademark) manufactured by Rohm and Haas Electronic Materials Co., Ltd., which is a positive photoresist, is used. Next, the photoresist layer 4 is exposed using a photomask for forming the outer shape of the tuning fork crystal unit (FIG. 6C). Then, the exposed photoresist layer 4 is developed so that the photoresist layer 4 remains only inside the outer shape of the tuning fork crystal unit (FIG. 6D).
Next, the Au film 3 is removed by etching (FIG. 7A). For etching the Au film 3, for example, an etching solution in which iodine is dissolved in a potassium iodide solution is used. Subsequently, the groove portion is exposed to the remaining photoresist layer 4 (FIG. 7B) and developed to remove the portion of the photoresist layer 4 corresponding to the groove portion (FIG. 7C). ).

  Next, an underlayer is formed by vapor deposition or sputtering on the other surface of the quartz substrate 1 on which the photoresist layer 4, the Cr film 2, and the Au film 3 are not formed (hereinafter, this surface is referred to as the back side of the quartz substrate 1). A Cr film 5 is formed as a metal film of about 250 mm, and then an Au film 6 is stacked as a surface metal film on the surface of about 1200 mm (FIG. 7D).

Next, a photoresist is applied to the surface of the Au film 6 and dried to form a photoresist layer 7 (FIG. 8A). As the photoresist, for example, S1800 (registered trademark) manufactured by Rohm and Haas Electronic Materials Co., Ltd., which is a positive photoresist, is used. Subsequently, the photoresist layer 7 is exposed using a photomask for forming the outer shape of the tuning fork crystal resonator (FIG. 8B). Then, the photoresist film 4 is heat-treated without developing the photoresist layer 7 on the back side (not shown). The heat treatment is performed at 90 ° C. or more for 10 minutes or more by placing the quartz substrate 1 in a drying furnace. The purpose of this heat treatment is the same as the heat treatment described in the first embodiment, and removes the developer, rinse solution and moisture remaining in the photoresist 4 and improves the adhesion between the resist film 4 and the Au film 3. The resist film 7 is developed in the next step for the purpose of improving the resistance to the developer. Therefore, this process may be performed after the outer shape of the vibrator and the groove pattern are formed on the photoresist layer 4 on the front surface side and before the development of the photoresist layer 7 formed on the back surface side. In the embodiment, the process may be performed after the step of FIG. 7C to the step of developing the photoresist layer 7 performed after the step of FIG. 8B.
The steps after heat-treating the photoresist layer 4 are the same as those after the step of FIG.

  As described above, in the embodiments of the present invention, the description has been given of the substantially H-type tuning fork type crystal resonator. However, the material of the piezoelectric material is not limited to quartz, and the present invention is appropriately applied even when other piezoelectric materials are used. be able to. Further, the shape of the piezoelectric vibrator is not limited to the substantially H-shaped tuning fork type, and it is apparent that the piezoelectric vibrator can be applied to, for example, an inverted mesa vibrator of an AT plate crystal.

FIG. 3 is a diagram illustrating a manufacturing process of a piezoelectric vibrator of the present invention (Example 1). FIG. 3 is a diagram illustrating a manufacturing process of a piezoelectric vibrator of the present invention (Example 1). FIG. 3 is a diagram illustrating a manufacturing process of a piezoelectric vibrator of the present invention (Example 1). FIG. 3 is a diagram illustrating a manufacturing process of a piezoelectric vibrator of the present invention (Example 1). FIG. 3 is a diagram illustrating a manufacturing process of a piezoelectric vibrator of the present invention (Example 1). FIG. 6 is a diagram showing a manufacturing process of a piezoelectric vibrator of the present invention (Example 2). FIG. 6 is a diagram showing a manufacturing process of a piezoelectric vibrator of the present invention (Example 2). FIG. 4 is a diagram showing a manufacturing process of the piezoelectric vibrator of the present invention (Example 2). It is a figure of the tuning fork type crystal resonator concerning this invention, (a) is a top view, (b) is AA sectional drawing. The figure which shows the conventional manufacturing method of a tuning fork type crystal resonator. The figure which shows the conventional manufacturing method of a tuning fork type crystal resonator. The figure which shows the conventional manufacturing method of a tuning fork type crystal resonator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Quartz substrate 2 Cr film 3 Au film 4 Photoresist layer 5 Cr film 6 Au film 7 Photoresist layer 11 Tuning fork type crystal vibrator 12 Leg 13 Groove 101 Crystal substrate 102 Cr film 103 Ag film 104 Photoresist layer 105 Groove

Claims (3)

In the method of manufacturing a piezoelectric vibrator made of a piezoelectric material and having a groove,
Forming a first metal film comprising a base layer and a surface layer on both surfaces of a piezoelectric substrate made of a piezoelectric material;
Applying a photoresist on one surface layer of the first metal film to form a first photoresist layer;
Applying a photoresist on the other surface layer of the first metal film to form a second photoresist layer;
Exposing and developing the first photoresist layer and patterning the outer shape of the piezoelectric vibrator to form a first resist pattern;
Removing the surface layer of the first metal film by etching using the first resist pattern as an etching mask;
Exposing and developing the first resist pattern and patterning the outer shape of the groove of the piezoelectric vibrator to form a second resist pattern;
Exposing and developing the second photoresist layer and patterning the outer shape of the piezoelectric vibrator to form a third resist pattern;
Removing the surface layer of the second metal film by etching using the third resist pattern as an etching mask;
Exposing and developing the third resist pattern and patterning the outer shape of the groove of the piezoelectric vibrator to form a fourth resist pattern;
Using the second resist pattern and the fourth resist pattern, the surface layer of the first metal film and the surface layer of the second metal film as an etching mask, the first metal film and the second metal film Removing the base layer of the metal film by etching, exposing the surface of the piezoelectric substrate other than the position corresponding to the outer shape of the piezoelectric vibrator; and
Removing the piezoelectric substrate exposed up to the previous step by etching;
Using the second resist pattern and the fourth resist pattern as an etching mask, the first metal film and the second metal film are removed by etching, and the piezoelectric substrate at a position corresponding to the groove portion of the piezoelectric vibrator A step of exposing
A step of removing a certain amount of the piezoelectric substrate corresponding to the groove portion of the piezoelectric substrate by etching to form a groove portion,
A piezoelectric process comprising a step of heat-treating the second resist pattern after the step of forming the second resist pattern and before development in the step of forming the third resist pattern. A method for manufacturing a vibrator. In the method of manufacturing a piezoelectric vibrator made of a piezoelectric material and having a groove,
Forming a first metal film comprising a base layer and a surface layer on one surface of a piezoelectric substrate made of a piezoelectric material;
Applying a photoresist on the surface layer of the first metal film to form a first photoresist layer;
Exposing and developing the first photoresist layer and patterning the outer shape of the piezoelectric vibrator to form a first resist pattern;
Removing the surface layer of the first metal film by etching using the first resist pattern as an etching mask;
Exposing and developing the first resist pattern and patterning the outer shape of the groove of the piezoelectric vibrator to form a second resist pattern;
Forming a second metal film comprising a base layer and a surface layer on the other surface of the piezoelectric substrate;
Applying a photoresist on the surface layer of the second metal film to form a second photoresist layer;
Exposing and developing the second photoresist layer and patterning the outer shape of the piezoelectric vibrator to form a third resist pattern;
Removing the surface layer of the second metal film by etching using the third resist pattern as an etching mask;
Exposing and developing the third resist pattern and patterning the outer shape of the groove of the piezoelectric vibrator to form a fourth resist pattern;
Using the second resist pattern and the fourth resist pattern, the surface layer of the first metal film and the surface layer of the second metal film as an etching mask, the first metal film and the second metal film Removing the base layer of the metal film by etching, exposing the surface of the piezoelectric substrate other than the position corresponding to the outer shape of the piezoelectric vibrator; and
Removing the piezoelectric substrate exposed up to the previous step by etching;
Using the second resist pattern and the fourth resist pattern as an etching mask, the first metal film and the second metal film are removed by etching, and the piezoelectric substrate at a position corresponding to the groove portion of the piezoelectric vibrator A step of exposing
A step of removing a certain amount of the piezoelectric substrate corresponding to the groove portion of the piezoelectric substrate by etching to form a groove portion,
A piezoelectric process comprising a step of heat-treating the second resist pattern after the step of forming the second resist pattern and before development in the step of forming the third resist pattern. A method for manufacturing a vibrator.   The method for manufacturing a piezoelectric vibrator according to claim 1, wherein the surface layer of the metal film is gold and the base layer is chromium.

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