JP4492044B2 - Method for forming resist in photolithography process and method for manufacturing piezoelectric vibrating piece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming method of a resist in a photolithography process by which a fine resist pattern can precisely be formed on the electrode film of a substrate irrespective of the area of a part of the substrate where the electrode film is formed by using the photolithography process; and to provide a manufacturing method of a piezoelectric oscillating piece, the piezoelectric oscillating piece, a piezoelectric device, an electronic apparatus, and a portable telephone unit. <P>SOLUTION: When an electrode film 22 is charged, an adjusting conductive film 22c is formed for adjusting the charge distribution of an electrode film 22a in a part whose area is wide in the piezoelectric oscillating piece 32 and the charge distribution of an electrode film 22b in a part whose area is narrow in the piezoelectric oscillating piece 32, so that it follows the electrode film 22b of the part whose area is narrow in the piezoelectric oscillating piece 32. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a resist in a photolithography process in which a resist particle is formed by electrostatically coating resist particles charged to a different polarity from the electrode film on a substrate charged with the electrode film. The present invention relates to a method for manufacturing a piezoelectric vibrating piece, a piezoelectric vibrating piece, a piezoelectric device, an electronic apparatus, and a mobile phone device.
[0002]
[Prior art]
2. Description of the Related Art In recent years, miniaturization and thinning of devices have been remarkable in small information devices such as HDDs (hard disk drives), mobile computers, and IC cards, and mobile communication devices such as portable telephone devices, automobile phones, and paging systems. The piezoelectric devices used for these are also required to be small and thin. In order to reduce the size and thickness of the piezoelectric device, it is required to reduce the size of the built-in piezoelectric vibrating piece, and accordingly, the electrode film of the piezoelectric vibrating piece is required to be finely patterned.
Conventionally, as a method of forming an electrode film on a piezoelectric vibrating piece, for example, a resist particle is electrostatically applied to a substrate coated with an electrode film made of Cr or Au and charged with a resist having a polarity different from that of the electrode film. A forming method is known (see, for example, Patent Document 1).
[0003]
FIG. 18 is a plan view showing an example of a procedure of a conventional method of manufacturing a piezoelectric vibrating piece 132 using resist electrostatic coating, and FIG. 19 is an example of a state in which a positive charge is charged on the electrode film. FIG. In FIG. 19, the electrode film is not shown.
In the conventional method of manufacturing the piezoelectric vibrating piece 132, for example, an ultrafine particle generator (not shown) is used to apply a resist used when forming an electrode film on the piezoelectric vibrating piece 132. This ultrafine particle generator generates resist particles containing a solvent of a photoresist in a fine particle generator, and mixes the resist particles with a carrier gas and sends it to a nozzle of a coating chamber.
[0004]
The fine particle generator is configured to electrostatically apply resist particles to the piezoelectric vibrating piece 132 disposed in the coating chamber by a high voltage applied to the nozzle, thereby forming a resist on the piezoelectric vibrating piece 132. It has become. It is assumed that the resist particles are negatively charged, for example, and the piezoelectric vibrating piece 132 is positively charged, for example.
[0005]
When electrostatically applying resist particles to the piezoelectric vibrating piece 132 shown in FIG. 18, positive charges are charged in the piezoelectric vibrating piece 132 and densely charged in the vibrating arms 134 and 135 as shown in FIG. It is known that the base 151 and the like are sparsely charged.
[0006]
20 and 21 are cross-sectional views showing an example in which a procedure for forming a resist by electrostatic coating of resist particles and forming an electrode film 122 in a predetermined pattern is simplified. 20 and 21, the left side shows the cross-sectional configuration of the base 151, and the right side shows the cross-sectional configuration of the vibrating arm 134 of FIG. 18. Note that the vibrating arm 135 has substantially the same configuration as the vibrating arm 134, and thus description thereof is omitted. In FIG. 20 and FIG. 21, the thickness is exaggerated in consideration of ease of visual recognition.
[0007]
First, the piezoelectric vibrating piece 132 is formed on, for example, a quartz wafer, and the surfaces of the vibrating arm 134, the base 151, and the like are covered with the metal electrode film 122 as described above. As shown in FIG. 20A, the ultrafine particle generator has a resist fine particle in which the electrode film 122 formed on the base 151 and the vibrating arm 134 has a positive charge, and has a negative charge, for example, as described above. It has a function of applying 132b using an electrostatic application method as shown in FIG.
[0008]
The resist fine particles 132b having a predetermined thickness applied to the base 151 and the vibrating arm 134 constitute a resist 1137 as shown in FIG. Next, a mask MSK configured corresponding to a predetermined electrode pattern is disposed on the resist 1137 as shown in FIG. 20D, and on the base 151 and the vibrating arm 134 as shown in FIG. A resist 1137 corresponding to a predetermined electrode pattern is formed.
Next, an electrode film 122 is formed in a predetermined pattern using a resist 1137 as shown in FIG. 21A, and the resist 1137 is removed as shown in FIG. An electrode 122 a having a predetermined pattern is formed on 134.
[0009]
[Patent Document 1]
JP 2002-290181 A
[0010]
[Problems to be solved by the invention]
However, in such a resist forming method in the photolithography process, as shown in FIG. 20B, the charge density charged on the electrode film 122 differs depending on the area of the resist to be formed. Specifically, for example, the positive charge 132c tends to be sparsely charged on the wide electrode film 122 on the base 151 side, and the positive charge 132c tends to be densely charged on the narrow electrode film 122 on the vibrating arm 134 side.
[0011]
When the positive charges 132b are charged in the electrode film 122 in this way, the amount of the resist fine particles 132b applied on the electrode film 122 per unit area differs between the base 151 side and the vibrating arm 134, and as a result, FIG. As shown in (C), there is a problem that the thickness of the resist 1137 is different as d1 and d2. That is, when the resist 1137 is applied by the electrostatic application method, the resist 1137 is thick on the electrode film 122 having a narrow pattern such as the vibrating arm 134 and has an area such as the base 151 as shown in FIG. The electrode film 122 having a wide pattern is thinly formed.
[0012]
In a portion where a large amount of resist particles 132b are applied, for example, on the vibrating arm 134 side, the particles gather and dissolve to become a wet state, and further, the resist particles 132b gather in the central portion to further increase the coating thickness. On the other hand, in a portion where the resist particles 132b are applied in a small amount, for example, the base 151, the resist particles 132b are not dissolved and are in a dry state.
[0013]
When exposure / development is performed in such a state as shown in FIG. 21 (A), the application thickness d2 is thick and wet in the vibrating arm 134. As shown, a resist residue 1137a is generated. On the other hand, since the coating thickness d1 is thin on the base 151 side and is in a dry state, development after exposure proceeds too quickly, and there is a possibility that the resist pattern may be cut off on the electrode film 122. Therefore, conventionally, there has been a problem that a fine pattern of electrodes cannot be accurately formed on a substrate such as the piezoelectric vibrating piece 132 using a photolithography process.
[0014]
Accordingly, an object of the present invention is to eliminate the above-mentioned problems and form a fine resist pattern on the electrode film of the substrate with high accuracy by using a photolithography process regardless of the area of the portion of the substrate on which the electrode film is formed. A method of forming a resist in a photolithography process, a method of manufacturing a piezoelectric vibrating piece, a piezoelectric vibrating piece, a piezoelectric device, an electronic apparatus, and a mobile phone device are provided.
[0015]
[Means for Solving the Problems]
The first object is to form a resist by electrostatically applying resist particles charged to a different polarity from the electrode film on a substrate charged with the electrode film and coated with the electrode film. A method of forming a resist in a photolithography process, wherein when the electrode film is charged, the charge distribution of the electrode film in a large area of the substrate and the charge distribution of the electrode film in a small area of the substrate An adjustment conductive film forming step for forming an adjustment conductive film so as to be adjacent to an electrode film having a small area in the substrate, an electrode film having a large area in the substrate, and the electrode film A resist forming step of electrostatically applying the resist particles to the electrode film having a small area on the substrate and dissolving the applied resist particles to form the resist; And a resist pattern forming step of forming the resist pattern on the electrode film of the substrate by performing exposure using a mask corresponding to a resist pattern corresponding to an adjustment conductive film and an electrode to be formed. This is achieved by a method for forming a resist in a lithography process.
[0016]
According to the said structure, the electrically conductive film for adjustment is formed so that it may adjoin along the part which should form an area narrowly. The conductive film for adjustment is for adjusting the charge distribution of the electrode film in the large area of the substrate and the charge distribution of the electrode film in the small area of the substrate at the time of electrostatic coating. is there. When such an adjustment conductive film is provided, the potential difference between the electrode film having a large area and the electrode film having a small area becomes small in electrostatic coating of resist particles. The amount of resist particles applied is approximately equal.
Accordingly, the thickness of the resist pattern formed on the electrode film having a large area is substantially equal to the thickness of the resist pattern formed on the electrode film having a small area. In this way, a resist pattern having a uniform thickness is formed on the electrode film. For this reason, in the photolithography process, an electrode with a fine pattern can be accurately formed on the substrate regardless of the area of the electrode film.
[0017]
According to a second invention, in the configuration of the first invention, the substrate is a base material of a piezoelectric vibrating piece.
According to the above configuration, in the photolithography process, a fine resist pattern is accurately formed on the electrode film of the piezoelectric vibrating piece regardless of the area of the base portion of the piezoelectric vibrating piece on which the electrode film is formed. be able to. For this reason, the electrode of a fine pattern can be accurately formed in the piezoelectric vibrating piece, and the piezoelectric vibrating piece can be miniaturized.
[0018]
According to a third aspect of the present invention, in the configuration of the second aspect of the invention, the piezoelectric vibrating piece base member is separated from the piezoelectric vibrating piece in which the resist pattern is formed on the electrode film. And a dummy frame integrally formed on the piezoelectric vibrating piece through a support portion, and the adjustment conductive film is formed on the dummy frame.
According to the above configuration, since the dummy frame is integrally formed with the piezoelectric vibrating piece via the support portion so as to be separated from the piezoelectric vibrating piece, the formation process of forming the adjustment conductive film on the dummy frame It can process collectively in the manufacturing process of a vibration piece.
[0019]
According to the fourth aspect of the present invention, there is provided an outer shape forming step of etching the substrate to form an outer shape of the piezoelectric vibrating piece from the substrate, and the piezoelectric vibrating piece coated with the electrode film and charged to the electrode film. On the other hand, a piezoelectric process comprising: a photolithography process for forming a resist by electrostatically applying resist particles charged to a different polarity from the electrode film; and an electrode forming step for forming an electrode on the piezoelectric vibrating piece using the resist. In the method of manufacturing a vibrating piece, the photolithography process includes charging the electrode film with a large area in the piezoelectric vibrating piece and charging the electrode film with a small area in the piezoelectric vibrating piece. An adjustment conductive film forming step for forming an adjustment conductive film for adjusting the charge distribution of the electrode film so as to be adjacent to the electrode film having a small area in the piezoelectric vibrating piece; The resist particles are electrostatically applied to the electrode film having a large area in the piezoelectric vibrating piece and the electrode film having a small area in the piezoelectric vibrating piece, and the applied resist particles are dissolved to dissolve the resist. Forming a resist pattern on the electrode film of the piezoelectric vibrating piece by exposing using a mask corresponding to the resist pattern corresponding to the conductive film for adjustment and the electrode to be formed This is achieved by a method of manufacturing a piezoelectric vibrating piece including a forming step.
According to the said structure, the electrically conductive film for adjustment is formed so that it may adjoin along the part which should form an area narrowly. The conductive film for adjustment is adjusted so that the charge distribution of the electrode film in the large area of the piezoelectric vibrating piece and the charge distribution of the electrode film in the small area of the piezoelectric vibrating piece are substantially equal during electrostatic application. Is for. When such an adjustment conductive film is provided, the potential difference between the electrode film having a large area and the electrode film having a small area becomes small in electrostatic coating of resist particles. The amount of resist particles applied is approximately equal.
Accordingly, the thickness of the resist pattern formed on the electrode film having a large area is substantially equal to the thickness of the resist pattern formed on the electrode film having a small area. In this way, a resist pattern having a uniform thickness is formed on the electrode film. For this reason, in the photolithography process included in the method of manufacturing a piezoelectric vibrating piece, an electrode with a fine pattern can be accurately formed on the piezoelectric vibrating piece regardless of the area of the electrode film.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.
FIG. 1 is a plan view illustrating a configuration example of a piezoelectric device 30 on which a piezoelectric vibrating piece 32 is mounted, and FIG. 2 is a cross-sectional view taken along a line CC in FIG.
In these drawings, the piezoelectric device 30 shows an example in which a piezoelectric vibrator is configured. The piezoelectric device 30 houses a piezoelectric vibrating piece 32 in a package 36. The package 36 is, for example, a substrate such as an aluminum oxide sintered body obtained by laminating and sintering ceramic green sheets, and is formed in a shallow box shape. Each laminated substrate (not shown) is configured so as to form a predetermined internal space S on the inner side when it is laminated by forming a predetermined hole inside thereof.
[0025]
In the inner space S of the package 36, in the vicinity of the left end portion, electrode portions 31 and 31 plated with Au and Ni are provided on the base substrate that is exposed to the inner space S and forms the bottom. ing. The electrode portions 31 are connected to the outside to supply a driving voltage. Conductive adhesives 43, 43 are applied on the electrode portions 31, 31, and the base 51 of the piezoelectric vibrating piece 32 is placed on the conductive adhesives 43, 43. 43 are hardened.
An extraction electrode (not shown) for transmitting a driving voltage is formed on a portion of the base 51 of the piezoelectric vibrating piece 32 that is in contact with the conductive adhesives 43 and 43. Thereby, the drive electrode of the piezoelectric vibrating piece 32 is electrically connected to the electrode portions 31 and 31 on the package 36 side via the conductive adhesives 43 and 43.
[0026]
The piezoelectric vibrating piece 32 is formed of, for example, quartz, and a piezoelectric material such as lithium tantalate or lithium niobate can be used in addition to quartz. The piezoelectric vibrating piece 32 includes a package 36 side and a fixed base 51. The piezoelectric vibrating piece 32 includes a pair of vibrating arms 34 and 35 that extend in parallel with a base 51 as a base end, and is a so-called tuning fork type piezoelectric vibrating piece that is shaped like a tuning fork as a whole. Is configured.
[0027]
Further, as shown in FIG. 1, long grooves 45 and 46 are formed in the pair of vibrating arms 34 and 35 of the piezoelectric vibrating piece 32 along the length direction thereof. In the piezoelectric vibrating piece 32, the details of the piezoelectric vibrating piece 32 and the piezoelectric device 30 can be reduced by forming the electrodes 22a and 22b having a fine electrode pattern using a photolithography process characteristic in the present embodiment. Can be achieved. In addition to the vibrating arms 34 and 35, electrodes 22a and 22b are formed on the base 51 and the like. The upper end of the package 36 is sealed by bonding a lid 39 via a brazing material 33 such as low melting point glass.
[0028]
FIG. 3 is a plan view showing a configuration example of the electrodes 22a and 22b as an example of an electrode film to be formed on the piezoelectric vibrating piece 32 shown in FIG.
For example, an electrode 22 a and an electrode 22 b are formed on the surface of the piezoelectric vibrating piece 32. Here, in the present embodiment, the electrode 22a is illustrated as an electrode formed on the base 51 as an example of a portion having a large area in the piezoelectric vibrating piece 32, and for example, as an example of a portion having a small area in the piezoelectric vibrating piece 32 The electrode 22b is illustrated as an electrode formed on the vibrating arm 34. Since the vibrating arms 34 and 35 have substantially the same configuration, the following description will mainly illustrate the vibrating arm 34.
[0029]
In addition, the electrode 22a formed on the base 51 as an example of a large area portion in the piezoelectric vibrating piece 32 is referred to as a wide portion electrode 22a, and vibration as an example of a narrow area portion in the piezoelectric vibrating piece 32. The electrode 22b formed on the arm 34 is referred to as a narrow portion of the electrode 22b. Further, a thin electrode having a large area in the piezoelectric vibrating piece 32 like the base 51 is referred to as a thin electrode 22d having a wide area.
[0030]
The details of the wide portion electrode 22a, the narrow portion 22b, and the wide portion thin electrode 22d will be described later. On the electrode film formed on the base material of the piezoelectric vibrating piece 32, for example, by an electrostatic coating method. The resist is formed using a photolithography process using a resist formed by applying resist particles. In the case of using this photolithography process, it is necessary to pay attention so that the pattern of the fine electrode 22b is not thick, and furthermore, the thin electrode 22d in a wide part does not cause the pattern to be cut off. Therefore, the piezoelectric vibrating piece 32 is manufactured by adopting a resist formation method in a photolithography process, which will be described later, which is characteristic in the present embodiment.
[0031]
FIG. 4 is a schematic cross-sectional view showing a configuration example of an ultrafine particle generator 130 that forms a resist by applying resist particles to the base 51 and the vibrating arms 34 and 35 using an electrostatic coating method.
The ultrafine particle generator 130 includes a fine particle generator 131, a high voltage power source 138, and a coating chamber 133.
[0032]
The fine particle generator 131 generates submicron resist fine particles 132a containing a solvent for the photoresist 132 used in the photolithography process. The generated resist fine particles 132a are carried to the nozzle part 134 of the coating chamber 133 by an inert gas carrier gas such as air or nitrogen. A high voltage power supply 138 is connected to the coating chamber 133.
[0033]
The high-voltage power supply 138 has a function of applying a negative high voltage of about 30 kV to 100 kV to the nozzle part 134 of the coating chamber 133 to negatively charge the resist fine particles 132b to generate resist fine particles 132b. The coating chamber 133 includes a positive electrode 136 in addition to the nozzle part 134. The positive electrode 136 is grounded, and a conductive member disposed on the positive electrode 136 is configured to be grounded. The nozzle unit 134 has a function of applying the resist fine particles 132b carried by the carrier gas to the vibrating arm 34 or the like disposed on the positive electrode 136 in the coating chamber 133 by an electrostatic coating method.
[0034]
An electrode film is formed in advance on the entire surface of the vibrating arm 34 and the like disposed on the positive electrode 136, and a resist 137 is formed on the electrode film 22 by applying resist fine particles 132b. The resist 137 is for forming an electrode film previously formed on the vibrating arm 34 and the like into a predetermined pattern through a photolithography process.
As described above, the fine particle generator 130 can adjust the film thickness of the resist 137 formed on the vibrating arm 34 and the like in accordance with the voltage applied by the high voltage power source 138.
[0035]
An outline of a method of forming the resist 137 on the vibrating arm 34 and the like by the fine particle generator 130 will be further described. In the following description, the resist 137 is formed on the electrode film 22 formed on the vibrating arm 34 as an example. In the present embodiment, the electrode film 22 is an electrode film formed on one surface of the target member, and the electrodes formed on the piezoelectric vibrating piece 32 through the photolithography process are referred to as electrodes 22a, 22b, and 22d. It is out.
[0036]
FIGS. 5A to 5C are cross-sectional views illustrating an example of a procedure for forming a resist 137 on the electrode film 22 on the vibrating arm 34.
As shown in FIG. 4, a negative high voltage is applied to the nozzle part 134, and the electrode film 22 of the vibrating arm 34 is grounded. Accordingly, a positive charge is charged on the electrode film 22 on the vibrating arm 34 corresponding to the negative high voltage of the nozzle portion 134 shown in FIG.
[0037]
Then, the nozzle portion 134 that moves relative to the vibrating arm 34 applies the resist fine particles 132b to the electrode film 22 on the vibrating arm 34, and the resist fine particles 132b vibrate as shown in FIG. The electrode film 22 on the arm 34 is attracted by the electric charge of the electrode film 22 and applied to the electrode film 22 on the vibrating arm 34. Then, as shown in FIG. 5C, a resist 137 made of the resist fine particles 132b is formed on the electrode film 22 on the vibrating arm.
[0038]
The piezoelectric vibrating piece 32 is configured as described above. Next, an example of a procedure of a method for manufacturing the piezoelectric vibrating piece 32 including a resist forming method in a photolithography process will be described with reference to FIGS.
FIGS. 6 to 10 and FIGS. 11 to 14 are a plan view and a cross-sectional view showing an example of how the resist 137 is formed by applying the resist fine particles 132b, respectively. 11 and 12 show an example in which a resist 137 is formed on the electrode film 22 on the base 51, and FIGS. 13 and 14 show that the resist 137 is formed on the electrode film 22 on the vibrating arms 34 and 35. An example is shown.
[0039]
First, as shown in FIG. 6, the crystal wafer etched according to the outer shape of the piezoelectric vibrating piece 32 is formed by arranging the outer shapes of the piezoelectric vibrating pieces 32. 22 is formed on the entire surface. A penetrating portion 21 is formed around the piezoelectric vibrating piece 32 by the outer shape etching. In addition, in FIG. 6, the penetration part 21 is illustrated by hatching.
[0040]
<Adjusting conductive film forming step>
Here, what is characteristic in the embodiment of the present invention is that, when the resist fine particles 132b are electrostatically coated, as shown in FIG. 6 and a charge distribution of the vibrating arm 34 as an example of a portion having a small area in the quartz wafer, a dummy electrode film 22c as an adjustment conductive film is formed on the quartz wafer as shown in FIG. The area is formed so as to be adjacent to the electrode film 22 on the vibrating arm 34 as an example of a portion that cannot be pushed.
[0041]
Further, the crystal wafer as an example of the base material of the piezoelectric vibrating piece 32 is separated from the piezoelectric vibrating piece 32 in which a resist pattern is formed on the electrode film 22 formed in advance as described later, and the piezoelectric vibrating piece 32. Thus, a dummy frame DF integrally formed with the piezoelectric vibrating piece 32 via the support portion 49 is provided. The dummy electrode film 22c as the adjustment conductive film is formed on the dummy frame DF. Therefore, the dummy electrode film 22c is formed so as to be adjacent to the electrode film 22 of the vibrating arm 34 as an example of a portion having a small area of the crystal wafer.
[0042]
As shown in FIG. 4, when the resist fine particles 132a are electrostatically applied to the electrode film 22 on the base and the electrode film 22 on the vibrating arm 34, the ultrafine particle generator 130 first converts the crystal wafer into the positive electrode 136. To charge. As shown in FIG. 7, the positive charge 132c is charged to the electrode film 22 on the quartz wafer. In this electrode film 22, due to the presence of the dummy frame DF, the charge distribution of the electrode film 22 on the base 51 and the charge distribution of the electrode film 22 of the vibrating arm 34 become substantially equal, and the electrode film 22 on the base 51 and the vibrating arm The potential difference between the 34 electrode films 22 is reduced. This is because the presence of the dummy frame DF causes, for example, the positive charge 132c charged on the dummy electrode film 22c of the dummy frame DF to repel and disperse with the positive charge 132c charged on the electrode film 22 on the vibrating arm 34, This is because the amount of charge charged in each electrode film 22 is adjusted to be equal.
[0043]
<Resist formation step>
Next, as shown in FIG. 11A, on the electrode film 22a on the base 51, as shown in FIG. 11B, the resist fine particles 132b from the nozzle part 134 have a uniform coating thickness on the electrode film 22a. Thinly applied. On the other hand, as shown in FIG. 13A, the electrode film 22b on the vibrating arm 34 is similarly coated with the resist fine particles 132b from the nozzle portion 134 as shown in FIG. Apply uniformly and thinly.
[0044]
FIG. 8 shows a state where the resist fine particles 132b are formed on one surface of the electrode film 22 on the piezoelectric vibrating piece 32 or the dummy frame DF. FIG. 8 shows an example of a state in which the resist fine particles 132b are uniformly applied to the entire surface of the crystal wafer other than the through portion 21. In the present embodiment, the film thickness of the electrode film 22a on the base 51 and the electrode film 22b on the vibrating arm 34 are substantially uniform as shown in FIGS. 11B and 13B.
[0045]
The resist fine particles 132b are uniformly applied in this way because the bias of the charge distribution in the electrode film 22b on the vibrating arm 34 side is compared to the charge distribution in the electrode film 22a on the base 51 as shown in FIG. This is because it is improved over the prior art. That is, as shown in FIG. 13B, the charge distribution charged on the electrode film 22b on the vibrating arm 34 is adjusted by the charge distribution charged on the dummy electrode film 22c on the dummy frame DF. In this way, the potential difference between the electrode film 22b on the vibrating arm 34 side and the electrode film 22a on the base 51 side is adjusted.
[0046]
The applied resist fine particles 132b are not dissolved, wetted and fluidized as shown in FIGS. 11C and 13C, and the electrodes 22a on the base 51 and the electrodes on the vibrating arm 34 are not fluidized. A resist 137 having a substantially uniform film thickness can be formed on 22b.
[0047]
<Resist pattern formation step>
Next, masks 71 shown in FIGS. 11 (D) and 13 (D) respectively corresponding to the wide portion electrode 22a, the narrow portion electrode 22b (and the wide portion thin electrode 22d) shown in FIG. The resist 137 is exposed. Then, as shown in FIG. 11D, the electrode film 22a on the base 51 has a small area on the resist pattern 137a and the electrode film 22b on the vibrating arm 34 has a small area as shown in FIG. A partial resist pattern 137b is formed. These resist patterns 137a and 137b have substantially the same coating thickness because the amount of resist fine particles to be applied is adjusted.
[0048]
For example, a pattern for removing the resist 137 formed on the dummy electrode film 22c is preferably formed on the mask 71. With such a structure, a mask 71 is arranged as shown in FIG. 13D, and a resist pattern 137b having a small area is formed on the electrode film 22 on the vibrating arm 34 as shown in FIG. When formed, the resist pattern 137b can be automatically left on the dummy electrode film 22c on the dummy frame DF.
[0049]
When the resist patterns 137a and 137b are formed, the structure shown in FIG. 9 is obtained. In this state where the resist patterns 137a and 137b are formed, the resist 137 is removed from the dummy frame DF. That is, when exposure is performed with the mask 71 disposed, desired resist patterns 137a and 137b are left on the base 51, the vibrating arm 34, and the like, but at the same time, no resist pattern is left on the dummy frame DF. be able to.
[0050]
Next, when the electrode film 22a is etched according to the wide resist pattern 137a shown in FIG. 11E and the electrode film 22b is etched according to the narrow resist pattern 137b shown in FIG. The electrode 22a having a large area can be formed on the base 51 shown in FIG. 12A, and the electrode 22b having a small area can be formed on the vibrating arm 34 shown in FIG. Then, the resist pattern 137a on the wide portion electrode 22a and the resist pattern 137b on the narrow portion electrode 22b are peeled off.
Therefore, as shown in the drawing, the piezoelectric vibrating piece 32 does not have the resist patterns 137a and 137b as shown in FIGS. 12B and 14B, and has a desired pattern as shown in FIG. A wide portion electrode 22a and a narrow portion electrode 22b are formed with high accuracy.
[0051]
In the above embodiment, the electrode 22a having a large area is formed on the base 51, and the electrode having a small area and the electrode 22b are formed on the vibrating arm 34. However, the present invention is not limited thereto. Specifically, in the present embodiment, not only the case where the wide portion electrode 22a is formed on the base 51 as an example of the wide portion, but also the thin electrode 22d is formed on the base 51 using a photolithography process. It can also be applied to. This is because the charge distribution of the entire electrode film on the piezoelectric vibrating piece 32 is similarly adjusted by the presence of the dummy electrode film 22c on the dummy frame DF as shown in FIG. That is, the present embodiment can be applied to the case where the fine electrode 22d having a fine pattern is accurately formed on the base 51 as an example of the wide area portion. Cutting can also be prevented.
[0052]
Next, from the piezoelectric vibrating piece 32 on which the electrodes 22a and the like are formed, the dummy frame DF and the like are removed, and individual piezoelectric vibrating pieces 32 as shown in FIG. 3 are completed. Next, in the piezoelectric vibrating piece 32, a base 51 is disposed on the conductive adhesives 43 and 43 in the package 36 configured as shown in FIG. 1 and FIG. Cured. An extraction electrode (corresponding to the electrode 22 a having a large area) for transmitting a driving voltage is formed on a portion of the base 51 of the piezoelectric vibrating piece 32 that comes into contact with the conductive adhesive 43. As a result, in the piezoelectric vibrating piece 32, the driving electrode is electrically connected to the electrode portions 31 and 31 on the package 36 side via the conductive adhesives 43 and 43.
[0053]
Next, the upper end of the package 36 containing the piezoelectric vibrating piece 32 is sealed by bonding a lid 39 via a brazing material 33 such as low melting point glass. Next, the frequency of the piezoelectric vibrating piece 32 is adjusted by evaporating a part of the electrode film on the surface thereof, and the piezoelectric device 30 is completed.
[0054]
FIG. 15 is a diagram illustrating an example of the coating thickness of the resist 137 formed on the electrode film 22 on the piezoelectric vibrating piece 32. Note that the coating thickness d of the resist 137 when there is a dummy frame DF corresponds to the coating thickness d shown in FIGS. 12A and 14A, and the resist coating thickness when there is no dummy frame DF is This corresponds to the coating thicknesses d1 and d2 shown in FIG.
In FIG. 15, when the resist 137 is formed by providing the dummy frame DF (the left side in the figure), the coating thickness of the resist 137 and when the resist 137 is formed without providing the dummy frame DF (the right side in the figure) Comparison of coating thickness.
[0055]
First, the coating thickness d of the resist pattern 137a formed on the electrode film 22a on the base 51 is about 2.0 μm in the same manner when the dummy frame DF is not provided or when the dummy frame DF is provided. Therefore, as shown in FIG. 11E, when the resist pattern 137a having a large area is formed on the electrode film 22a on the base 51, there is little influence whether or not the dummy frame DF is provided. I understand.
[0056]
On the other hand, the coating thickness d of the resist 137b formed on the electrode film 22b on the vibrating arm 34 is about 4.5 μm when the dummy frame DF is not provided, but is 3 when the dummy frame DF is provided. About 5 μm. Accordingly, when the resist pattern 137a having a small area is formed on the electrode film 22a on the base 51 as shown in FIG. 11E, and the electrode film 22b on the vibrating arm 34 as shown in FIG. In the case where the resist pattern 137b having a small area is formed thereon, the coating thickness d can be made thin and uniform by providing the dummy frame DF.
[0057]
Further, characteristics of the coating thicknesses d, d1, d2 of the resist pattern 137b formed on the electrode 22b on the vibrating arm 34 with respect to the coating thicknesses d, d1, d2 of the resist pattern 137a formed on the electrode 22a on the base 51 ( The following can be understood by referring to the “arm / base” shown in the figure, and hereinafter referred to as “coating thickness ratio”. In FIG. 15, the coating thickness d, d1, d2 [μm] is shown as the vertical axis, but the unit of the vertical axis of the characteristics of the coating thickness ratio is the coating thickness d, d1, d2 [ It is shown without using [μm].
[0058]
The coating thickness ratio decreases such that the numerical value approaches 1 as the coating thickness d of the resist pattern 137b formed on the electrode film 22b on the vibrating arm 34 decreases. Here, since the coating amount is constant, the lower coating thickness ratio indicates that the film thickness of the resist 137 is uniformly applied to the entire electrode film 22 of the piezoelectric vibrating piece 32.
[0059]
Specifically, the coating thickness ratio is lower so that the coating thickness ratio is closer to 1 when the dummy frame DF is provided than when the dummy frame DF is not provided. Therefore, it can be seen that the resist 137 can be uniformly formed on the electrode film 22 of the piezoelectric vibrating piece 32 by providing the dummy frame DF and forming the resist 137.
[0060]
According to the embodiment of the present invention, when the dummy electrode film 22c is provided as described above, a portion of the electrode film 22a having a large area in the piezoelectric vibrating piece of the resist 137 when the resist fine particles 132b are electrostatically applied, and The charge density of the resist 137 with the portion of the electrode film 22b having a small area in the piezoelectric vibrating piece of the resist 137 can be made substantially equal, and the potential difference between the two can be reduced. As described above, in the electrode film 22 in the wide portion and the electrode film 22b in the narrow portion, the amount of the resist fine particles 132b applied per unit area when the resist fine particles 132b are electrostatically applied is substantially equal. Therefore, according to the present embodiment, the photolithography process is used to form a fine pattern on the electrode film 22 of the piezoelectric vibrating piece 32 regardless of the area of the piezoelectric vibrating piece 32 as an example of the substrate on which the electrode film 22 is formed. Resist patterns 137a and 137b can be formed with high accuracy.
[0061]
Therefore, the coating thickness d of the resist pattern 137a formed on the electrode film 22a having a large area is substantially equal to the coating thickness d of the resist pattern 137b formed on the electrode film 22b having a small area. Therefore, according to the present embodiment, the electrode film 22 having a fine pattern can be accurately formed through the photolithography process regardless of the area. Therefore, according to the present embodiment, for example, the electrode 22 having various widths is not cut in the pattern using the photolithography process on the ultra-small piezoelectric vibrating piece 32 that has been conventionally limited by the photolithography process. Can be formed.
[0062]
In the above embodiment, the electrode 22a having a large area and the electrode 22b having a small area are formed on the tuning fork type piezoelectric vibrating piece 32. However, the present invention is not limited to this. For example, when forming an electrode of a gyro sensor. Needless to say, the present invention may be applied to the case where a resist is formed using a photolithography process. Hereinafter, a configuration example of the gyro sensor will be briefly described.
[0063]
FIG. 16 is a schematic plan view showing a schematic configuration of a gyro sensor as an example of a piezoelectric device. In FIG. 16, the X direction indicates the electrical axis of the crystal, the Y direction indicates the mechanical axis of the crystal, and the Z direction indicates the optical axis (growth axis) of the crystal.
The gyro sensor 80 includes a sensor main body 81 accommodated in a package 98 using a piezoelectric material or the like. The package 98 accommodates the sensor main body 81 in substantially the same manner as described in the first embodiment. It is formed in a box-like form, and includes a drive means such as an excitation circuit for exciting the sensor body 81, a circuit for detecting vibration from the sensor body 81, and the like (not shown).
[0064]
The sensor body 81 is formed by etching a crystal. In FIG. 16, the substantially square base 82 of the sensor body 81 is fixed to the package 98. A thick electrode and a thin electrode are formed on the base portion 82 as an example of a wide area portion, and support portions 83, 83 formed integrally with the base portion 82 extend in the left and right directions from the base portion 82. ing. The support portions 83 and 83 are a part of the base portion 82.
At the end of each support portion 83, 83, a vibrating arm for excitation extended in both directions starting from the end of each support portion 83, 83 in a direction orthogonal to the extending direction of each support portion 83, 83. 84, 84 are provided. That is, the vibrating arms 84 and 84 for excitation extend in parallel to each other from the base portion 82 through the support portions 83 and 83 which are parts of the base portion 82. Each of the vibrating vibrating arms 84 and 84, which is an example of a portion having a small area, is provided with long grooves 94 and 94 arranged in the length direction, and an electrode such as an excitation electrode is formed.
[0065]
Further, in FIG. 16, two detection vibrating arms 85, 85 are formed at a substantially central portion of the upper and lower pieces of the fixing portion 82 in a direction orthogonal to the extending direction of the support portions 83, 83. One detection vibrating arm 85 extends upward in FIG. 16, and the other detection vibrating arm 85 extends downward in FIG. 16, and the detection vibrating arms 85, 85 and each support portion 83, The vibration arms 84 and 84 for excitation provided at the end of 83 are parallel to each other. The detection vibrating arm 85 corresponds to, for example, a portion having a small area in the above-described embodiment, and an electrode having a narrow portion in the above-described embodiment is formed.
[0066]
In FIG. 16, the excitation vibrating arms 84 and 84 of the gyro sensor 80 are applied with a driving voltage from an excitation circuit (not shown) as a driving means, so that their tip portions are separated from each other as indicated by arrows E and E. Vibrate as they approach and separate. At this time, as shown in FIG. 16, when the rotational angular velocity ω acts around the center O of the fixed portion 82 in the plane of the paper, the Coriolis force acts in the directions of F and F in FIG. This vibration is transmitted to the detection vibrating arms 85 and 85 via the support portions 83 and 83 and the fixed portion 82. In other words, the excitation vibrating arms 84 and 84 receive the Coriolis force Fc acting in the direction of the vector product of the direction of vibration in the X-axis direction and the rotational angular velocity ω, and along the Y-axis (plus Y direction and minus It vibrates (alternately in the Y direction) (walk vibration). This vibration is transmitted to the detection vibrating arms 85 and 85 via the support portions 83 and 83.
[0067]
<Application example>
FIG. 17 is a diagram illustrating a schematic configuration of a digital mobile phone device 300 as an example of an electronic apparatus using the piezoelectric device manufactured by the manufacturing method according to the above-described embodiment of the present invention.
In the figure, a microphone 308 for receiving the voice of the sender and a speaker 309 for outputting the received content as a voice output are provided, and further, an integrated circuit or the like as a control unit connected to the modulation and demodulation unit of the transmission / reception signal. The CPU 301 is provided.
[0068]
In addition to modulation and demodulation of transmission / reception signals, the CPU 301 includes an information input / output unit 302 such as an LCD as an image display unit and operation keys for inputting information, and a memory 303 as information storage means such as a RAM and a ROM. Control is to be performed. For this reason, for example, the piezoelectric device 30 is attached to the CPU 301, and the output frequency is used as a clock signal suitable for the control contents by a predetermined frequency dividing circuit (not shown) built in the CPU 301 or the like. Has been.
[0069]
The CPU 301 as a controller is further connected to a temperature compensated crystal oscillator (TCXO) 305, and the temperature compensated crystal oscillator 305 is connected to the transmission unit 307 and the reception unit 306. Thus, even if the basic clock from the CPU 301 fluctuates when the environmental temperature changes, it is corrected by the temperature compensated crystal oscillator 305 and supplied to the transmission unit 307 and the reception unit 306.
As described above, by using the piezoelectric device 30 or the gyro sensor 80 according to the above-described embodiment in an electronic apparatus such as the digital cellular phone device 300 including the control unit, the size can be reduced.
[0070]
The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the claims. For example, a part of each configuration of the above embodiment can be omitted, or can be arbitrarily combined so as to be different from the above.
Moreover, although the said embodiment is applied when forming a resist, it is not restricted to this, It can apply also when forming various films other than a resist material.
[Brief description of the drawings]
FIG. 1 is a plan view illustrating a configuration example of a piezoelectric device on which a piezoelectric vibrating piece is mounted.
FIG. 2 is a cross-sectional view of the piezoelectric device CC shown in FIG.
FIG. 3 is a plan view illustrating a configuration example of an electrode.
FIG. 4 is a schematic cross-sectional view showing a configuration example of an ultrafine particle generator.
FIG. 5 is a cross-sectional view showing an example of a procedure for forming a resist on an electrode film of a vibrating arm.
FIG. 6 is a plan view showing an example of how a resist is formed.
FIG. 7 is a plan view showing an example of how a resist is formed.
FIG. 8 is a plan view showing an example of how a resist is formed.
FIG. 9 is a plan view showing an example of how a resist is formed.
FIG. 10 is a plan view showing an example of how a resist is formed.
FIG. 11 is a cross-sectional view showing an example of how a resist is formed.
FIG. 12 is a cross-sectional view showing an example of how a resist is formed.
FIG. 13 is a cross-sectional view showing an example of how a resist is formed.
FIG. 14 is a cross-sectional view showing an example of how a resist is formed.
FIG. 15 is a diagram showing an example of a resist coating thickness.
FIG. 16 is a schematic plan view showing a configuration example of a piezoelectric device.
FIG. 17 is a diagram showing a schematic configuration of a digital cellular phone device.
FIG. 18 is a plan view showing an example of a procedure of a conventional method for manufacturing a piezoelectric vibrating piece.
FIG. 19 is a plan view showing an example of a procedure of a conventional method of manufacturing a piezoelectric vibrating piece.
FIG. 20 is a cross-sectional view showing an example of a procedure for forming an electrode film in a predetermined pattern.
FIG. 21 is a cross-sectional view showing an example of a procedure for forming an electrode film in a predetermined pattern.
[Explanation of symbols]
22... Electrode film, 22 a... Wide portion electrode (electrode film having a large area in the piezoelectric vibrating piece) 22 b... Narrow portion electrode (electrode film having a small area in the piezoelectric vibrating piece) 22c ... dummy electrode film (adjusting conductive film), 30 ... piezoelectric device, 32 ... piezoelectric vibrating piece, 34, 35 ... vibrating arm (wide area of substrate, piezoelectric vibrating piece) Wide area), 43... Support part, 51... Base part (Wide area on the substrate, Wide area on the piezoelectric vibrating piece), 71... Mask, 132 a, 132 c. (Resist particles), 132c... Positive charge, 137... Resist, 137a... Electrode film resist pattern in a large area of the piezoelectric vibrating piece, 137b. Resist pattern had portions of the electrode film, 300 ... digital portable telephone apparatus (electronic apparatus, cellular phone device), DF.. Dummy Frame

Claims (4)

This is a resist forming method in a photolithography process in which a resist particle is formed by electrostatically applying resist particles charged to a different polarity from the electrode film on a substrate charged with the electrode film. And
When the electrode film is charged, an adjustment conductive film for adjusting the charge distribution of the electrode film having a large area in the substrate and the charge distribution of the electrode film having a small area in the substrate is provided on the substrate. An adjustment conductive film forming step that is formed so as to be adjacent along the electrode film of the narrow area in
A resist that forms the resist by electrostatically applying the resist particles to the electrode film having a large area on the substrate and the electrode film having a small area on the substrate, and dissolving the applied resist particles. Forming step;
A resist pattern forming step of performing exposure using a mask corresponding to a resist pattern corresponding to the adjustment conductive film and an electrode to be formed, and forming the resist pattern on the electrode film of the substrate. A method for forming a resist in a photolithography process.   The method for forming a resist in a photolithography process according to claim 1, wherein the substrate is a base material of a piezoelectric vibrating piece. The substrate of the piezoelectric vibrating piece is
The piezoelectric vibrating reed on which the resist pattern is formed on the electrode film;
A dummy frame integrally formed with the piezoelectric vibrating piece through a support portion so as to be separated from the piezoelectric vibrating piece;
3. The method for forming a resist in a photolithography process according to claim 2, wherein the adjustment conductive film is formed on the dummy frame. An outer shape forming step of etching the substrate and forming the outer shape of the piezoelectric vibrating piece from the substrate;
A photolithography process for forming a resist by electrostatically applying resist particles charged to a different polarity from the electrode film to the piezoelectric vibrating piece charged on the electrode film and charged to the electrode film;
An electrode forming step of forming an electrode on the piezoelectric vibrating piece using the resist, comprising:
The photolithography process includes:
A conductive film for adjustment for adjusting the charge distribution of the electrode film having a large area in the piezoelectric vibrating piece and the charge distribution of the electrode film having a small area in the piezoelectric vibrating piece during charging of the electrode film Forming a conductive film for adjustment, which is formed so as to be adjacent along an electrode film of a narrow area in the piezoelectric vibrating piece;
The resist particles are electrostatically applied to the electrode film having a large area in the piezoelectric vibrating piece and the electrode film having a small area in the piezoelectric vibrating piece, and the applied resist particles are dissolved to dissolve the resist. Forming a resist; and
A resist pattern forming step of performing exposure using a mask corresponding to a resist pattern corresponding to the conductive film for adjustment and the electrode to be formed, and forming the resist pattern on the electrode film of the piezoelectric vibrating piece. A method for manufacturing a piezoelectric vibrating piece.

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