JP2009246761A - Method of manufacturing piezoelectric vibration chip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a piezoelectric vibration chip, for forming a piezoelectric vibration chip with high accuracy and suppressing generation of foreign substances during manufacturing steps. <P>SOLUTION: In a method of manufacturing a grooved piezoelectric vibration chip, a resist pattern for forming an outer shape of the piezoelectric vibration chip and a resist pattern for forming a groove part 3 are formed as one resist pattern 33a through one-time exposure and development, and prior to forming the resist pattern 33a, a protecting layer 31 is formed in advance which protects a region with a pattern (opening) corresponding to the groove part 3 in the resist pattern 33a formed therein. By forming the protecting layer 31 prior to forming the resist pattern 33a, the protecting layer 31 can be accurately patterned without being affected by ruggedness in the microscopically three-dimensional resist pattern 33a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a piezoelectric vibrating piece.

  2. Description of the Related Art Conventionally, a so-called grooved piezoelectric vibrating piece in which a thick portion is provided with a groove for improving vibration characteristics is known as one of piezoelectric vibrating pieces made of a piezoelectric material such as quartz.

  2A and 2B are diagrams showing a grooved piezoelectric vibrating piece, which are (a) a plan view and (b) a cross-sectional view taken along line AA in (a). The grooved piezoelectric vibrating piece shown here is made of a piezoelectric material made of crystal, and is fixed to an external mounting substrate (package substrate) or the like, and extends from the base 1 along its main surface. Two branch portions 2 and rectangular groove portions 3 provided on both main surfaces of the two branch portions 2.

  3A, 3B, and 3C are cross-sectional views taken along line AA showing a conventional method for manufacturing the piezoelectric vibrating piece shown in FIG. When the grooved piezoelectric vibrating piece shown in FIG. 2 is manufactured, first, on both main surfaces of a flat plate-like quartz substrate (quartz wafer) 11 as shown in FIG. -1 (b), a first metal layer 12 made of Cr (chromium) and a second metal layer 13 made of Au (gold) are sequentially formed, and then FIG. 3-1 (c) As shown in FIG. 2, a negative photoresist layer 14 is formed by uniformly applying a negative photoresist material to the entire surface of the second metal layer 13.

  Thereafter, as shown in FIG. 3D, the region where the negative resist layer 14 is formed is exposed at a time within the outer region of the piezoelectric vibrating piece and excluding the region where the groove 3 is to be formed. Then, by removing the negative resist layer 14 in the unexposed area with a developer, a negative resist pattern 14a having an opening corresponding to a region outside the outer region of the piezoelectric vibrating piece and a region where the groove 3 is to be formed is formed. .

  Thereafter, as shown in FIG. 3E, the positive photoresist material is uniformly applied to the entire surface of the second metal layer 13 including the surface of the negative resist pattern 14a exposed to the outside at this time. To form a positive resist layer 15.

  After that, as shown in FIG. 3-2 (f), the region except for the periphery of the region where the groove 3 is to be formed is exposed in the region where the positive resist layer 15 is formed, and the positive resist in the exposed region is exposed. By removing the layer 15 with a developing solution, a positive resist pattern (protective layer) 15a covering the periphery of the region where the groove 3 is to be formed is formed.

  After that, as shown in FIG. 3-2 (g), the second metal layer 13 in the exposed region is removed by wet etching using the negative resist pattern 14a and the positive resist pattern 15a as an etching mask, and subsequently exposed thereby. The first metal layer 12 is removed by wet etching.

  Thereafter, as shown in FIG. 3-2 (h), the positive resist pattern 15a covering the periphery of the region where the groove 3 is to be formed is removed with a stripping solution, and then shown in FIG. 3-2 (i). Thus, the external shape of the piezoelectric vibrating piece is formed by removing the exposed quartz substrate 11 by wet etching using the negative resist pattern 14a and the second metal layer 13 as an etching mask.

  Thereafter, as shown in FIG. 3-2 (j), the second metal layer 13 in the exposed region is removed by wet etching using the negative resist pattern 14a as an etching mask, and then the first metal exposed thereby is exposed. By removing the layer 12 by wet etching, the crystal substrate 11 is exposed from the region where the groove 3 is to be formed.

  After that, as shown in FIG. 3-3 (k), the negative resist pattern 14a is removed with a stripping solution, and then the quartz substrate exposed from the formation region of the groove 3 as shown in FIG. 3-3 (l). 11 is removed by a certain amount in the depth direction by wet etching to form the groove 3.

Thereafter, as shown in FIG. 3-3 (m), the first metal layer 12 and the second metal layer 13 remaining at this time are all removed by wet etching to complete the grooved piezoelectric vibrating piece. To do. (For example, see Patent Document 1)
JP 2007-295330 A

  In the conventional manufacturing method of the piezoelectric vibrating piece described above, as shown in FIG. 3D, the resist pattern for forming the outer shape of the piezoelectric vibrating piece and the resist pattern for forming the groove portion are: Since one resist pattern (negative resist pattern 14a) is simultaneously formed by the same exposure and development process, compared with the case where they are formed as two resist patterns by separate exposure and development processes, The positional deviation, that is, the positional deviation of the groove 3 with respect to the outer shape of the piezoelectric vibrating piece when the piezoelectric vibrating piece is completed is prevented, and the shape of the piezoelectric vibrating piece is formed with high accuracy.

  On the other hand, when two resist patterns are simultaneously formed as one resist pattern as described above, the first metal layer exposed from the region where the groove 3 is to be formed in the step shown in FIG. 3-2 (g). 12 and the second metal layer 13 should be protected by a layer (protective layer) resistant to etching at the stage before etching, in order to avoid the removal of the metal layer 13 and the second metal layer 13 by etching. In view of this point, in the conventional manufacturing method, after forming the negative resist pattern 14a for forming the outer shape of the piezoelectric vibrating piece and the groove 3 on the surface of the second metal layer 12 in the step shown in FIG. At this time, a positive resist pattern 15a is formed as a protective layer so as to cover the surface of the second metal layer 12 exposed from the region where the groove 3 is to be formed.

  However, the positive resist pattern 15a for protecting the region where the groove 3 is to be formed is shown in FIG. 3-2 (e) after the outer shape of the piezoelectric vibrating piece and the negative resist pattern 14a for forming the groove 3 are formed. As shown in FIG. 3-2 (f), the photoresist material is coated by applying a positive photoresist material so as to cover the entire surface, and then patterned by exposure and development. Depending on the thickness of the resist pattern 14a, in the process, a photo is formed in a concave corner portion constituted by the side surface of the negative resist pattern 14a, which is a three-dimensional structure, and the surface of the second metal layer 13 below the microscopic three-dimensional structure. Etching of the metal layers (first metal layer 12 and second metal layer 13) shown in FIG. 3-2 (g) in which a residue of the resist material (positive type) remains, and the residue continues. There is a risk that the outer shape of the metal layer will change and the shape of the piezoelectric vibrating piece will eventually change, or the residue will be released during the manufacturing process and prevent other manufacturing processes from being performed normally or completed. There is a possibility of adhering to the piezoelectric vibrating piece in the state as a foreign substance. In particular, since the outer shape of the piezoelectric vibrating piece is an important parameter that determines the vibration characteristics (frequency) and impedance characteristics of the piezoelectric vibrating piece, the outer shape accuracy is very important.

  FIG. 4 is a diagram schematically showing a state in which a residue remains around the resist pattern. When the residue 16 remains on the side surface of the negative resist pattern 14a and the corner of the second metal layer 13, FIG. Etching of the first metal layer 12 and the second metal layer 13 is hindered, and the outer shapes of the first metal layer 12 and the second metal layer 13 may change as shown in the figure.

  In particular, the outer shape of the piezoelectric vibrating piece, the resist pattern (negative resist pattern 14a) for forming the groove 3 and the protective layer (positive resist pattern 15a) for protecting the region where the groove is to be formed have different properties (positive type or If it is composed of negative-type photosensitive materials, these mutually opposite components permeate each other and change in quality, and the above-mentioned problems are more likely to occur due to a decrease in peelability with respect to the stripping solution. There is a risk of becoming.

  In addition, since a negative photoresist material is a so-called photocrosslinking type photoresist material in which a polymer (photosensitive agent) in the material is cross-linked by exposure, generally a line width of several μm level is stably provided. It is said that it is difficult to obtain, and at the level of several μm, the obtained pattern is rattling as if it hits a wave, and a linear outline line cannot be obtained.

  The present invention has been made in view of the above problems, and is a piezoelectric vibrating piece capable of forming the shape of the piezoelectric vibrating piece with high accuracy and suppressing the generation of foreign matters during the manufacturing process. It aims at providing the manufacturing method of.

  A method of manufacturing a piezoelectric vibrating piece provided with a groove, comprising at least a metal layer forming step of forming a metal layer on a surface of a substrate, and at least a surface of the metal layer within an outer region of the piezoelectric vibrating piece. A protective layer forming step of forming a protective layer covering a region where the groove is to be formed; a photoresist layer forming step of forming a photoresist layer on the surface of the metal layer including the surface of the protective layer; and the photoresist layer. A resist pattern forming step of exposing and developing to form a resist pattern in which an opening outside the outer region of the piezoelectric vibrating piece and an opening corresponding to a region where the groove is to be formed are formed simultaneously; and the resist pattern and the resist pattern A first etching process for removing the metal layer in the exposed region by etching using the protective layer exposed from the opening of the etching mask as an etching mask And removing the substrate exposed by the first etching step by etching to form an outer shape of the piezoelectric vibrating piece, and removing the protective layer from the first etching step to the second A protective layer removing step for removing at an arbitrary timing until after the etching step, a third etching step for removing the metal layer exposed by the protective layer removing step by etching, and the third etching step. And removing the substrate exposed by etching through a fourth etching step to form the groove.

  The method may be a method of manufacturing a piezoelectric vibrating piece in which the protective layer is removed together with the metal layer by the first etching step.

  The method may be a method for manufacturing a piezoelectric vibrating piece in which the protective layer is removed together with the substrate by the second etching step.

  The protective layer forming step includes a step of forming a protective material layer on the surface of the metal layer formed by the metal layer forming step, a step of forming a photoresist layer on the surface of the protective material layer, and the photoresist. Exposing and developing the layer, forming a resist pattern covering at least the region where the groove is to be formed in the outer region of the piezoelectric vibrating piece, and etching the protective material layer in the exposed region using the resist pattern as an etching mask The step of removing may be a method for manufacturing a piezoelectric vibrating piece.

  The metal layer forming step includes a first metal layer forming step for forming a first metal layer on the surface of the substrate, and a second metal for forming a second metal layer on the surface of the first metal layer. The first etching step includes a second metal layer etching step for removing the second metal layer by etching, and the first metal layer etching step exposed by the second metal layer etching step. And a first metal layer etching step of removing one metal layer by etching.

  The second metal layer may be made of a metal material having a smaller ionization tendency than the first metal layer, and the protective layer may be a method for manufacturing a piezoelectric vibrating piece made of a non-metal material.

The first metal layer is made of Cr, the second metal layer is made of Au, and the protective layer is made of Si, SiO ₂ , or Al ₂ O ₃ Can be a method.

  The second metal layer is composed of a metal material having a smaller ionization tendency than the first metal layer, and the protective layer is a piezoelectric composed of a metal material having a greater ionization tendency than the second metal layer. It can be set as the manufacturing method of a vibration piece.

  The protective layer may be a method for manufacturing a piezoelectric vibrating piece made of a metal material having the same or higher ionization tendency as the first metal layer.

  The first metal layer is made of Cr, the second metal layer is made of Au, and the third metal layer is made of a piezoelectric vibrating piece made of Cr or Ti. obtain.

  According to the present invention, the protective layer covering the region where the groove is to be formed is formed before the resist pattern for forming the outer shape of the piezoelectric vibrating piece and the groove is formed. It is possible to improve the external accuracy of the resonator element, and in addition, it is possible to suppress the generation of residues when forming the protective layer.

  1-1, FIG. 1-2, and FIG. 1-3 are AA cross-sectional views showing the manufacturing method of the present invention for the piezoelectric vibrating piece shown in FIG. When the grooved piezoelectric vibrating piece shown in FIG. 2 is manufactured using the manufacturing method of the present invention, first, on both main surfaces of the plate-like crystal substrate 11 as shown in FIG. Further, as shown in FIG. 1-1 (b), the first metal layer 12 made of Cr (chromium), the second metal layer 13 made of Au (gold), and Si (silicon) using a sputtering method or the like. A protective layer 31 is sequentially formed.

  Thereafter, as shown in FIG. 1-1C, a negative photoresist material is uniformly applied to the entire surface of the protective layer 31 to form a photoresist layer 32. Subsequently, as shown in FIG. As shown in FIG. 5B, the region where the groove 3 is to be formed is exposed using a photomask among the regions where the photoresist layer 32 is formed, and the photoresist layer 32 in the unexposed region is removed with a developer. Thus, a resist pattern 32a is formed to cover the region where the groove 3 is to be formed. There are two types of photoresist materials, positive type and negative type, which can be properly used according to the manufacturing process.

  The resist pattern 32a formed here only needs to cover at least the entire region where the groove 3 is to be formed as long as it falls within the outer region of the piezoelectric vibrating piece to be formed, and does not protrude outside the outer region of the piezoelectric vibrating piece. As long as there is not, the pattern which covers the range wider than the formation area of the groove part 3 may be sufficient. Note that if the resist pattern 32a protrudes outside the outer region of the piezoelectric vibrating piece at this time, the exposed region is protected when the first metal layer 12 and the second metal layer 13 are etched in a later process. There is a possibility that the layer 31 prevents the progress of etching, thereby changing the outer shapes of the first metal layer 12 and the second metal layer 13 and finally changing the outer shape of the piezoelectric vibrating piece.

  Thereafter, as shown in FIG. 1-1E, wet etching using the resist pattern 32a as an etching mask and the protective layer 31 in the exposed region using hydrofluoric acid or buffered hydrofluoric acid that is a mixture of hydrofluoric acid and ammonium fluoride. The protective layer 31 is patterned into a shape that covers only the region where the groove 3 is to be formed. In the step shown in FIG. 1-1D, when the resist pattern 32a for patterning the protective layer 31 is formed in a pattern covering a wider area than the region where the groove 3 is to be formed. Thus, the protective layer 31 is patterned into a pattern larger than the region where the groove is to be formed.

  As described above, since the protective layer 31 is formed after depositing the layer material (Si) on the flat surface of the second metal layer 13, other resist patterns, etc., as in the conventional manufacturing method. Compared with the case where the layer material is deposited on the three-dimensional structure, the layer material has a relatively small thickness, such as a concave corner formed between the side surface of the three-dimensional structure and its lower layer. Since there is no recessed portion that is difficult to remove and part of which tends to remain as a residue, patterning of the layer material can be performed accurately. Further, since no residue of the layer material is generated, the residue is not released during the subsequent process, preventing the manufacturing process from being normally performed, and does not adhere as a foreign matter to the completed piezoelectric vibrating piece.

  Thereafter, as shown in FIG. 1-2 (f), the resist pattern 32a after use is removed with a resist stripping solution, and then the surface including the surface of the protective layer 31 is removed as shown in FIG. 1-2 (g). A positive photoresist material is uniformly applied to the entire surface of the second metal layer 13 to form a photoresist layer 33. Subsequently, as shown in FIG. 1-2 (h), the photoresist layer 33 is formed. Of the exposed region, all the regions outside the outer shape region of the piezoelectric vibrating reed to be formed and the region where the groove 3 is to be formed are exposed at once using a single photomask, and the exposed region of the photoresist layer By removing 33 with a developing solution, a resist pattern 33a is formed that covers the region outside the outer region of the piezoelectric vibrating piece except the region where the groove 3 is to be formed.

  In the resist pattern 33a formed here, since a single photomask is used when exposing the photoresist layer 33, a pattern corresponding to the outer shape of the piezoelectric vibrating piece and a pattern corresponding to the outer shape of the groove portion 3 are used. And a high pattern accuracy equivalent to that of the conventional manufacturing method is ensured. Furthermore, since the resist pattern 33a is made of a positive photoresist material, the pattern outline line is smaller than that of a conventional resist pattern (negative resist pattern 14a) made of a negative photoresist material. It is formed with high accuracy.

  When the protective layer 31 is formed in a pattern larger than the region where the groove 3 is to be formed in the process shown in FIG. 1-1E, the outer peripheral portion of the protective layer 31 is the resist pattern 33a at this point. It becomes a state embedded in.

Thereafter, as shown in FIG. 1-2 (i), an etching solution (iodine-based etching solution) containing iodine as a main component of the second metal layer 13 in the exposed region using the resist pattern 33 a and the protective layer 31 as an etching mask. Then, the first metal layer 12 exposed by the wet etching used is removed from the first metal layer 12, as shown in FIG. 1-2 (j). Then, the quartz substrate 11 exposed by wet etching using a second cerium ammonium-based etching solution) is exposed to hydrofluoric acid or hydrofluoric acid and ammonium fluoride as shown in FIG. The outer shape of the piezoelectric vibrating piece is formed by removing by wet etching using buffered hydrofluoric acid which is a mixture of the above. At this time, the protective layer covering the forming region of the groove 3 (Si) 31 is quartz substrate (SiO ₂₎ quartz substrates from not resistant against 11 etchant for etching the (SiO ₂₎ 11 In addition, the second metal layer (Au) 13 underneath serves as an etching mask from the middle of etching.

  Thereafter, as shown in FIG. 1-3 (l), the second metal layer 13 exposed from the region where the groove 3 is to be formed is removed by wet etching using an iodine-based etchant, and subsequently exposed thereby. The first metal layer 12 is removed by wet etching using a ceric ammonium nitrate based etchant as shown in FIG. 1-3 (m), and the quartz substrate 11 exposed thereby is removed. As shown in FIG. 1-3 (n), the groove 3 is formed by removing a certain amount in the depth direction by wet etching using hydrofluoric acid or buffered hydrofluoric acid which is a mixture of hydrofluoric acid and ammonium fluoride. To do.

  Thereafter, as shown in FIG. 1-3 (o), after the resist pattern 33a after use is removed with a stripping solution, as shown in FIG. 1-3 (p), the remaining first metal layer 12 and The second metal layer 13 is removed by wet etching using a ceric ammonium nitrate etching solution and an iodine etching solution, respectively, thereby completing a grooved piezoelectric vibrating piece.

In the embodiment described above, the material of the protective layer 31 for protecting the region where the groove 3 is to be formed is not limited to Si, but an insulating material such as SiO ₂ (silicon dioxide) or Al ₂ O ₃ (alumina). Alternatively, a metal material such as Cr (chromium) or Ti (titanium) can be appropriately selected. Among them, SiO ₂ , Al ₂ O ₃ , and Ti are not resistant to an etching solution for etching the quartz substrate 11 like Si, and therefore, the material of the protective layer 31 is simply Si in the manufacturing process. Is simply replaced by SiO ₂ , Al ₂ O ₃ , and Ti. On the other hand, Cr is resistant to an etching solution when the quartz substrate 11 is etched. Therefore, Cr is not removed when the quartz substrate 11 is etched. In the process shown, the first metal layer (Cr) 12 outside the outer diameter region of the piezoelectric vibrating piece is removed by etching.

  The protective layer 31 is formed in a region where the groove 3 is to be formed when the second metal layer (Au) 13 existing outside the outer region of the piezoelectric vibrating piece is etched as shown in FIG. Since it plays a role of protecting the existing second metal layer (Au) 13 from being removed together, it is not necessary after fulfilling that role. FIG. 1-2 (i) After the second metal layer 13 is etched in the step shown, the protective film 31 may be removed at an arbitrary timing before the step shown in FIG. .

  Here, in the manufacturing method in the present embodiment described above, a laminate of the first metal layer (Cr) 12 and the second metal layer (Au) 13 which are different metals (dissimilar metals) is used. Therefore, when the first metal layer (Cr) 12 is etched as shown in FIG. 1-3 (j), the etching is unnecessary if the region where the groove 3 is to be formed is not protected by the protective layer 31. There is a possibility that a phenomenon called a so-called electric contact effect that the first metal layer (Cr) 12 is etched more than necessary is promoted.

  The electric contact effect is that a potential difference (electromotive force) is generated between different types of metals immersed in the electrolyte solution according to the principle of the battery, and a current is generated from a metal material with a lower ionization tendency to a higher metal material among the different types of metals. In the above manufacturing process, particularly when the first metal layer 12 is etched as shown in FIG. 1-3 (j), the etching solution is an electrolyte solution, and the first metal layer (Cr) 12 is used. Is a negative battery, and the second metal layer (Au) 13 is a positive battery, and the first metal layer (Au) 13 having a relatively low ionization tendency is used for the first higher than that. Current is generated toward the metal layer (Cr) 12, which accelerates ion exchange in the etching solution, thereby speeding up the etching of the first metal layer (Cr) 12. Note that it is difficult to control the etching in consideration of such an electric contact effect.

The electric contact effect can be effectively suppressed by covering the region where the groove 3 is to be formed with a protective layer 31 made of a non-metallic material such as Si, SiO ₂ , or Al ₂ O _3. In the case where a metal material is used as the material of the protective layer 31, the electric contact effect is large between the first metal layer (Cr) 12 and the protective layer 31 across the second metal layer (Au) 13. May occur.

  Therefore, in the case where a metal material is used as the material of the protective layer 31, the first metal layer is considered in view of the fact that the magnitude of the electric contact effect (potential difference) is mainly determined by the magnitude of the difference in ionization tendency between different metals. It is preferable to select a metal material that reduces the difference in ionization tendency between the (Cr) 12 and the protective layer 31.

  From this point of view, the metal material constituting the protective layer 31 is preferably a metal material having a higher ionization tendency than the second metal layer (Au) 13, and the first metal layer (Cr) 12 and It can be said that a metal material having the same or higher order of ionization tendency is more preferable. In order to make this easy to understand, when the relationship of the above ionization tendency is expressed by a mathematical expression, the order of the ionization tendency of the first metal layer (Cr) 12, the second metal layer (Au) 13, and the protective layer 31 is expressed as follows. When A, B, and C are set, C ≧ A> B.

  In addition, as a metal material satisfying the above relational expression among the metal materials exemplified in this specification, the same metal as the first metal layer (Cr) 12 and naturally having the same ionization tendency rank, This corresponds to Ti having a higher ionization tendency than the single metal layer (Cr) 12.

  Moreover, if the metal material which comprises the protective layer 31 is a metal material (Cr, Ti, etc.) with which an oxide is easy to be formed on the surface, the oxide will become an insulating layer and generation | occurrence | production of an electrolysis effect will be more effective. Can be suppressed.

  In this embodiment, the contact effect generated when the first metal layer (Cr) 12 is etched is that the ionization tendency of the second metal layer (Au) 13 is in the order of the first metal layer (Cr). Therefore, the second metal layer (Au) 13 is made of a metal material having the same ionization tendency as the first metal layer (Cr) 12 but higher than that of the first metal layer (Cr) 12. In theory, the electric contact effect does not occur. However, in reality, the original role of the second metal layer 13 as a corrosion-resistant layer, compatibility with the first metal layer 12, and cost (material) In consideration of the cost), it is necessary to select a material that satisfies all of these conditions within an allowable range, and the materials that can be used are extremely limited.

  Further, the manufacturing method of the present invention is not effective only when the metal layer is composed of two layers of the first metal layer and the second metal layer as in the embodiment described above. It is also effective when it is composed of only one layer or when it is composed of three or more layers.

  In addition, the piezoelectric vibrating reed that is a target of the manufacturing method of the present invention is not limited to a so-called tuning fork type piezoelectric vibrating reed having a branch portion, and may be a piezoelectric resonating reed having a rectangular shape in plan view.

AA sectional view showing the manufacturing method of the present invention of a piezoelectric vibrating piece AA sectional view showing the manufacturing method of the present invention of a piezoelectric vibrating piece AA sectional view showing the manufacturing method of the present invention of a piezoelectric vibrating piece It is a figure which shows a piezoelectric vibration piece with a groove | channel, (a) Top view, (b) AA sectional drawing of (a) AA sectional view showing a conventional method of manufacturing a piezoelectric vibrating piece AA sectional view showing a conventional method of manufacturing a piezoelectric vibrating piece AA sectional view showing a conventional method of manufacturing a piezoelectric vibrating piece Schematic diagram showing the state of residue remaining on the outer periphery of the resist pattern

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base part 2 Branch part 3 Groove part 11 Crystal substrate 12 1st metal layer 13 2nd metal layer 14 Negative resist layer 14a Negative resist pattern 15 Positive resist layer 15a Positive resist pattern 16 Residue 31 Protective layer 32 Photoresist layer 32a Resist pattern 33 Photoresist layer 33a Resist pattern

Claims (10)

A method of manufacturing a piezoelectric vibrating piece provided with a groove,
at least,
A metal layer forming step of forming a metal layer on the surface of the substrate;
A protective layer forming step of forming a protective layer on the surface of the metal layer and covering at least a region where the groove is to be formed in the outer region of the piezoelectric vibrating piece;
A photoresist layer forming step of forming a photoresist layer on the surface of the metal layer including the surface of the protective layer;
A resist pattern forming step of exposing and developing the photoresist layer to form a resist pattern in which an opening corresponding to a region outside the outer region of the piezoelectric vibrating piece and a region where the groove is to be formed is formed simultaneously;
A first etching step of removing the metal layer in the exposed region by etching using the resist pattern and the protective layer exposed from the opening of the resist pattern as an etching mask;
Removing the substrate exposed by the first etching step by etching to form an outer shape of the piezoelectric vibrating piece; and
A protective layer removing step of removing the protective layer at an arbitrary timing between the first etching step and after the second etching step;
A third etching step for removing the metal layer exposed by the protective layer removing step by etching;
Removing the substrate exposed by the third etching step by etching to form the groove, and a fourth etching step;
A method for manufacturing a piezoelectric vibrating piece, comprising:   The method for manufacturing a piezoelectric vibrating piece according to claim 1, wherein the protective layer is removed together with the metal layer by the first etching step.   The method for manufacturing a piezoelectric vibrating piece according to claim 1, wherein the protective layer is removed together with the substrate by the second etching step. The protective layer forming step includes
Forming a protective material layer on the surface of the metal layer formed by the metal layer forming step;
Forming a photoresist layer on the surface of the protective material layer;
Exposing and developing the photoresist layer, and forming a resist pattern covering at least the region where the groove is to be formed in the outer region of the piezoelectric vibrating piece;
Removing the protective material layer in the exposed region by etching using the resist pattern as an etching mask;
The method of manufacturing a piezoelectric vibrating piece according to claim 1, wherein The metal layer forming step includes
A first metal layer forming step of forming a first metal layer on the surface of the substrate;
A second metal layer forming step of forming a second metal layer on the surface of the first metal layer,
The first etching step includes
A second metal layer etching step of removing the second metal layer by etching;
A first metal layer etching step for removing the first metal layer exposed by the second metal layer etching step by etching;
The method of manufacturing a piezoelectric vibrating piece according to claim 1, wherein The second metal layer is made of a metal material having a smaller ionization tendency than the first metal layer,
The method for manufacturing a piezoelectric vibrating piece according to claim 5, wherein the protective layer is made of a non-metallic material. The first metal layer is made of Cr,
The second metal layer is made of Au,
The method for manufacturing a piezoelectric vibrating piece according to claim 6, wherein the protective layer is made of Si, SiO ₂ , or Al ₂ O ₃ . The second metal layer is made of a metal material having a smaller ionization tendency than the first metal layer,
The method for manufacturing a piezoelectric vibrating piece according to claim 5, wherein the protective layer is made of a metal material having a larger ionization tendency than the second metal layer.   9. The method of manufacturing a piezoelectric vibrating piece according to claim 8, wherein the protective layer is made of a metal material having an ionization tendency equal to or greater than that of the first metal layer. The first metal layer is made of Cr,
The second metal layer is made of Au,
The method for manufacturing a piezoelectric vibrating piece according to claim 9, wherein the third metal layer is made of Cr or Ti.

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