TW201830850A - Method of manufacturing piezoelectric vibration element capable of increasing alignment capability between the photoresist layer and the alignment mark - Google Patents

Abstract

The present invention relates to a method of manufacturing a piezoelectric vibration element, comprising: a step of preparing a piezoelectric substrate having a first main surface and a second main surface opposite thereto; a step of forming a first photoresist layer on the first main surface of the substrate and forming a second photoresist layer on the second main surface; a first exposure step of exposing the first photoresist layer using the first mask and transferring the first pattern and the first alignment mark on the first photoresist layer; a step of shooting images that takes a second alignment mark of the second mask and recording the captured image of the second alignment mark; a step of setting a relative position through adjusting substrate relative to the second mask based on the first alignment mark of the first photoresist layer and the captured image of the second alignment mark; a second exposure step of using the second mask and exposing the second photoresist layer and transferring the second pattern on the second photoresist layer; and a step of developing the first photoresist layer and the second photoresist layer.

Description

   Manufacturing method of piezoelectric vibration element   

The present invention relates to a method for manufacturing a piezoelectric vibration element.

As a signal source of a reference signal used in an oscillation device, a band-pass filter, and the like, a piezoelectric vibration element made of, for example, an artificial crystal is widely used. The piezoelectric vibration element includes mutually facing excitation electrodes on the principal surfaces of the piezoelectric substrate facing each other. In the manufacturing process of the piezoelectric vibration element, for example, when forming the external shape of the piezoelectric substrate, a photoresist layer is patterned on both surfaces of the substrate having piezoelectricity, and etching is performed from both surfaces of the substrate. When a single-sided exposure machine is used to form a pattern on both sides of a photoresist, a registration of the two-side pattern is required. For example, in Patent Document 1, it is disclosed that an alignment mark is formed on the substrate before the photoresist layer is formed, and the alignment mark of the photomask and the alignment mark of the photoresist layer are aligned to align the positions of the two-sided patterns. Methods.

Prior art literature

Patent literature

Patent Document 1: Japanese Patent Application Laid-Open No. 2004-45933

When the first photoresist on the first main surface side of the substrate transfers the first pattern and the first alignment mark, the first photoresist is developed, and the second photoresist on the second main surface side is developed. In the case where the second pattern and the second alignment mark are transferred, and the second photoresist is developed, the first alignment mark melts and flows out during the development process to change the external dimensions, so that there are the first alignment mark and the first alignment mark. There is a possibility that the alignment accuracy of the two alignment marks is reduced.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a piezoelectric vibration element capable of improving processing accuracy.

A method for manufacturing a piezoelectric vibration element according to an aspect of the present invention includes a step of preparing a piezoelectric substrate having a first main surface and a second main surface facing the first main surface, and a first main substrate on the substrate. In the step of forming a first photoresist layer on the surface side and forming a second photoresist layer on the second main surface side, the first photoresist layer is exposed using a first photomask, and the first photoresist layer is exposed on the first photoresist layer. A first exposure step of transferring the first pattern and the first alignment mark with the agent layer, a step of photographing the second alignment mark of the second mask, and recording a captured image of the second alignment mark, based on the first photoresist A step of adjusting the relative position of the first alignment mark and the second alignment mark on the substrate with respect to the second photomask, using the second photomask to expose the second photoresist layer, and A second exposure step of transferring two photoresist layers to a second pattern, and a step of developing the first photoresist layer and the second photoresist layer.

According to the above aspect, since the development step is not performed, the shape of the first alignment mark of the first photoresist layer is not changed, and the first alignment mark and the second photomask of the first photoresist layer can be improved. The alignment accuracy of the second alignment mark. Accordingly, it is possible to improve the processing accuracy of the etching step.

According to the present invention, it is possible to provide a method for manufacturing a piezoelectric vibration element capable of improving processing accuracy.

110‧‧‧ Piezoelectric substrate

111‧‧‧first main face

112‧‧‧Second main face

121‧‧‧ first metal layer

122‧‧‧Second metal layer

131‧‧‧first photoresist layer

132‧‧‧Second photoresist etchant layer

140‧‧‧Workbench

142‧‧‧Window

143‧‧‧Driver

144‧‧‧light source

145‧‧‧beam

151‧‧‧First photomask

MK1‧‧‧First alignment mark

PT1‧‧‧The first pattern

152‧‧‧Second photomask

MK2‧‧‧Second alignment mark

PT2‧‧‧Second Pattern

160‧‧‧Image processing device

161‧‧‧ Camera

162‧‧‧Monitor

163‧‧‧ Take an image

FIG. 1 is a flowchart showing etching of a substrate in a method of manufacturing a piezoelectric vibration element according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a substrate before being mounted on an exposure machine.

FIG. 3 is a diagram showing a substrate mounted on an exposure machine.

FIG. 4 is a diagram showing a step of exposing a first photoresist.

FIG. 5 is a diagram illustrating a procedure of photographing a second alignment mark of a second photomask.

FIG. 6 is a diagram showing a procedure for adjusting a position using an alignment mark.

FIG. 7 is a diagram showing a step of exposing a second photoresist.

FIG. 8 is a view showing a substrate after development.

FIG. 9 is an exploded perspective view of an example of a piezoelectric vibrator.

Fig. 10 is a sectional view taken along the line X-X of the piezoelectric vibrator shown in Fig. 9.

FIG. 11 is a perspective view of a piezoelectric vibration element according to a modification.

Hereinafter, embodiments of the present invention will be described. In the description of the following drawings, the same or similar constituent elements are indicated by the same or similar reference numerals. The drawings are for illustration, and the dimensions and shapes of the various parts are schematic, and should not be construed to limit the technical scope of the invention of the present application to this embodiment.

<Embodiment>

A method for manufacturing a piezoelectric vibration element according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8. Here, FIG. 1 is a flowchart showing etching of a substrate in a method of manufacturing a piezoelectric vibration element according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a substrate before being mounted on an exposure machine. FIG. 3 is a diagram showing a substrate mounted on an exposure machine. FIG. 4 is a diagram showing a step of exposing a first photoresist. FIG. 5 is a diagram illustrating a procedure of photographing a second alignment mark of a second photomask. Fig. 6 is a diagram showing a procedure of position adjustment using alignment marks. FIG. 7 is a diagram showing a step of exposing a second photoresist. FIG. 8 is a view showing a substrate after development.

An etching flow of a substrate 110 made of a piezoelectric material as a piezoelectric substrate using a single-sided exposure machine will be described with reference to FIG. 1. In the description of the following embodiments, for example, the piezoelectric vibration element is a Quartz Crystal Resonator, the piezoelectric substrate is a Quartz Crystal Blank, and the collective piezoelectric substrate is a Quartz Crystal. Wafer). However, embodiments of the present invention are not limited to these.

First, before starting the step, a substrate 110 made of a flat plate of artificial crystal as a piezoelectric material is prepared. At this time, the substrate 110 which is an artificial crystal is formed as a plane parallel to a plane specified by the X axis and the Z ′ axis (hereinafter referred to as “XZ ′ plane”. The same is also applied to the plane specified by the other axes). , Y ' axis is parallel to the normal direction of the principal surface. In addition, the Y ' axis and the Z ' axis are respectively the X axis, the Y axis, and the Z axis which are crystal axes of the artificial crystal. The Y axis and the Z axis are rotated by 35 degrees from the Y axis to the Z axis around the X axis 15 minutes ± 1 minute and 30 seconds of the axis.

Next, metal layers 121 and 122 are formed on the main surfaces 111 and 112 of the substrate 110 (S11). As shown in FIG. 2, the first metal layer 121 is formed on the first main surface 111 of the substrate 110, and the second metal layer 122 is formed on the second main surface 112 opposite to the first main surface 111. The first metal layer 121 and the second metal layer 122 function as an anti-corrosive film with respect to an etching solution (for example, ammonium fluoride or buffered hydrofluoric acid) used when etching a crystal. As the above-mentioned corrosion-resistant film, for example, a multilayer film composed of a chromium (Cr) layer and a gold (Au) layer is used. The metal layer is formed by a vapor deposition method or a sputtering method, and a Cr layer is provided on the first main surface 111 and the second main surface 112 of the substrate 110. The Au layer is provided in a layered manner on the Cr layer provided on the substrate 110. The Cr layer of the base layer improves the adhesion of the metal layer to the substrate 110, and the Au layer of the surface layer improves the corrosion resistance of the metal layer. In addition, in the case where the metal layer 121 or 122 is a multilayer film of three or more layers, as long as the Cr layer is located on the side closer to the substrate 110 than the Au layer, the Au layer is located on the side farther from the substrate 110 than the Cr layer. can.

Next, a first photoresist layer 131 is formed on the first metal layer 121 (S12). Next, a second photoresist layer 132 is formed on the second metal layer 122 (S13). The first photoresist layer 131 is formed by coating a photoresist solution containing a photoresist material on the metal layer 121 and evaporating the solvent by heating to form a film. The photoresist solution is applied by, for example, a spray method or a spin coating method. The second photoresist layer 132 is also formed in the same manner as the first photoresist layer 131. Through the above steps, as shown in FIG. 2, a substrate 110 having a photoresist layer on both sides of the first main surface 111 side and the second main surface 112 side is obtained. The photoresist layer is not particularly limited as long as it is a photosensitive resin, but from the viewpoint of processing accuracy of a pattern obtained by development, a positive-type photosensitive resin having high solubility in the exposed portion is used. .

Next, the first pattern PT1 of the first photomask 151 and the first alignment mark MK1 are transferred on the first photoresist layer 131 (S14). This step S14 is a first exposure step for exposing the first photoresist layer 131. Specifically, as shown in FIG. 3, first, the substrate 110 is mounted on a table 140 of a single-sided exposure machine. The stage 140 is provided with a protruding support portion 141, and the second photoresist etchant layer 132 is in contact with the support portion 141. In other words, the second photoresist layer 132 is located on the side of the table 140, and the first photoresist layer 131 is located on the side opposite to the table 140. The stage 140 includes a window portion 142 provided at a position facing the substrate 110. The window portion 142 is an opening portion penetrating the table 140, and the opposite side of the table 140 can be viewed. In other words, in the state shown in FIG. 3, the surface of the second photoresist layer 132 can be viewed through the window portion 142 of the table 140 from the side of the table 140 opposite to the side where the substrate 110 exists. In addition, a plurality of window portions 142 may be provided.

FIG. 4 is a view showing a step of exposing the first photoresist layer 131 using a cross-sectional view taken along a line IV-IV in FIG. 3. The stage 140 is driven by the driving unit 143 to adjust the position of the first photoresist layer 131 relative to the first photomask 151. After that, the first photoresist layer 131 is irradiated with the light beam 145 from the light source 144. A first pattern PT1 and a first alignment mark MK1 are drawn on the first mask 151. The first mask 151 allows the light beam 145 to pass therethrough or blocks the light beam 145 according to the first pattern PT1 and the first alignment mark MK1. That is, the first pattern PT1 and the first alignment mark MK1 are transferred to the first photoresist layer 131 by exposure using the first photomask 151. Physical properties such as the solubility of the transferred first pattern PT1 and the first alignment mark MK1 in the first photoresist layer 131 are different from those of the surroundings. In the subsequent development step, the difference in solubility is used, and by using The cleaning of the solvent removes a part of the first photoresist layer 131. The difference in physical properties also affects the optical characteristics, so that the first pattern PT1 and the first alignment mark MK1 in the first photoresist resist layer 131 may be optically recognized even if they are not developed. In addition, in order to improve the visibility of the first pattern PT1 and the first alignment mark MK1 in the first photoresist layer 131, the first photoresist layer 131 may also include a photoresist color changing material. Accordingly, the first photoresist layer 131 changes color according to the light beam 145 corresponding to the first pattern PT1 and the first alignment mark MK1.

Next, the second alignment mark MK2 of the second mask 152 is captured and the captured image 163 is recorded (S15). This step S15 will be described with reference to FIG. 5. First, in a state where the substrate 110 is not mounted, a second photomask 152 on which a second pattern PT2 and a second alignment mark MK2 are drawn is mounted. Next, the second mask 152 is irradiated with the light beam 145, and the second alignment mark MK2 is captured by the camera 161 of the image processing device 160. The camera 161 of the imaging device is located on the side of the table 140 opposite to the side where the second mask 152 exists, and photographs the second alignment mark MK2 of the second mask 152 through the window portion 142 of the table 140. Then, the image processing device 160 transmits the image of the second alignment mark MK2 captured by the camera 161 to the monitor 162 and records it as a captured image 163.

Next, position adjustment is performed so that the photographic image 163 and the photoresist of the alignment marks MK1 and MK2 on the first photoresist layer 131 can overlap (S16). This step S16 will be described with reference to FIG. 6. First, the substrate 110 is mounted on the table 140 so that the support portion 141 is in contact with the first photoresist layer 131, that is, the first photoresist layer 131 faces the camera 161 side. Next, the image processing device 160 acquires an image of the first alignment mark MK1 of the first photoresist layer 131 through the camera 161. Next, while maintaining the position of the second mask 152 relative to the light source 144 at the position in step S15, the table 140 is driven by the drive unit 143. Then, the positions of the substrate 110 (the first photoresist layer 131 and the second photoresist layer 132) are adjusted so that the first alignment mark MK1 of the first photoresist layer 131 for image acquisition is relative to The second alignment mark MK2 of the recorded captured image 163 is aligned.

Next, the second pattern PT2 of the second photomask 152 is transferred to the second photoresist layer 132 (S17). This step S17 is a second exposure step of exposing the second photoresist layer 132. As shown in FIG. 7, the exposure of the second photoresist layer 132 is the same as that of the first photoresist layer 131. Through this step S17, the second pattern PT2 and the second alignment mark MK2 are transferred to the second photoresist layer 132.

Next, the first photoresist layer 131 and the second photoresist layer 132 are developed (S18). Using the difference in solubility with respect to the developing solution caused by exposure, unnecessary portions of the first photoresist layer 131 and the second photoresist layer 132 are washed away by the developing solution. In the example shown in FIG. 8, the second photoresist resist layer 132 is a positive-type photosensitive resin, and the solubility is increased by exposure, so that the second pattern PT2 and the second alignment mark corresponding to the exposure are made. The second photoresist resist layer 132 of MK2 is removed. In addition, as shown in FIG. 8, a plurality of first alignment marks MK1 may be provided, and a plurality of second alignment marks MK2 may also be provided. In the case where a plurality of first alignment marks MK1 are provided, the separation of the plurality of first alignment marks MK1 from each other is beneficial to improve the alignment accuracy.

Next, etching is performed (S19). In this step S19, first, the first metal layer 121 corresponding to the first pattern PT1 and the second metal layer 122 corresponding to the second pattern PT2 are removed. Next, the substrate 110 corresponding to the first pattern PT1 and the second pattern is removed. The metal layer is removed, for example, by wet etching using an iodine-based etching solution. The crystal is removed by, for example, wet etching using a hydrofluoric acid-based etching solution.

As described above, the application example of the present embodiment of the step of forming a plurality of piezoelectric substrates on the substrate 110 has been described. That is, the first pattern PT1 and the second pattern PT2 are patterns for forming an outer shape of a plurality of piezoelectric substrates on the substrate 110. In this case, the first pattern PT1 of the first photoresist layer 131 is an outline pattern of the piezoelectric substrate when viewed from the normal direction of the first principal surface 111 of the substrate 110, and the second photoresist layer 132 The second pattern PT2 is an external shape pattern of the piezoelectric substrate when viewed from the normal direction of the second main surface 112 of the substrate 110 in a plan view. The first pattern PT1 of the first photoresist layer 131 preferably overlaps the second pattern PT2 of the second photoresist layer 132 with high accuracy in the normal direction of the first main surface 111.

However, the method for manufacturing a piezoelectric vibrating element of this embodiment can be applied to any step as long as a step of forming a pattern for each of the photoresist layers is required to form a photoresist layer on both sides. . For example, the substrate 110 may be an aggregate piezoelectric substrate having a plurality of piezoelectric substrates, and the first pattern PT1 and the second pattern PT2 may be patterns for changing the thickness of a part of the piezoelectric substrate. When the first pattern PT1 and the second pattern PT2 are patterns for forming a mesa structure, the first pattern PT1 of the first photoresist layer 131 and the second pattern of the second photoresist layer 132 are preferred. PT2 is a pattern formed so as to overlap the vibrating portion located in the center of the piezoelectric substrate, and overlaps each other with high accuracy in the normal direction of the first main surface 111. Then, in step S19 of etching, the substrate 110 is half-etched. In addition, for example, each of the first pattern PT1 and the second pattern PT2 may be a pattern for forming various electrodes on a piezoelectric substrate. In this case, the first pattern PT1 includes a pattern formed to overlap the vibration portion of the piezoelectric substrate in order to form the first excitation electrode, and the second pattern PT2 includes the pattern formed on the piezoelectric substrate to form the second excitation electrode. Pattern of overlapping vibrating parts. The portion of the first pattern PT1 of the first photoresist layer 131 corresponding to the first excitation electrode is preferably in the normal direction of the first main surface 111 and the second pattern PT2 of the second photoresist layer 132. The portion corresponding to the second excitation electrode overlaps with high accuracy. In the etching step S19, the first metal layer 121 and the second metal layer 122 are etched, and the substrate 110 is not etched.

In the manufacturing of the piezoelectric vibrating element, after the above-mentioned steps, a step of separating the piezoelectric substrate from the substrate 110 that becomes the aggregated piezoelectric substrate to form a small piece is performed. The piezoelectric substrate separated from the collective piezoelectric substrate is obtained as a piezoelectric vibration element including various electrodes.

As described above, according to the present embodiment, there is provided a method of manufacturing a piezoelectric vibration element including preparing a piezoelectric substrate having a first main surface 111 and a second main surface 112 opposed to the first main surface 111. Step 110, a step of forming a first photoresist layer 131 on the first main surface 111 side of the substrate 110, and a step of forming a second photoresist layer 132 on the second main surface 112 side. The first photoresist layer 131 is exposed to transfer the first pattern PT1 and the first alignment mark MK1 in the first photoresist layer 131, and the second alignment mark of the second photomask 152 is photographed. MK2 and recording the captured image 163 of the second alignment mark MK2, and the captured image 163 of the first alignment mark MK1 and the second alignment mark MK2 based on the first photoresist layer 131 is adjusted on the substrate 110 relative to the first A step of the relative positions of the two photomasks 152, a second exposure step of exposing the second photoresist layer 132 using the second photomask 152 to transfer the second pattern PT2 to the second photoresist layer 132, and Developed by the first photoresist layer and the second photoresist layer 131, 132 Sudden.

According to the above-mentioned embodiment, since the development step is not performed, the shape of the first alignment mark of the first photoresist layer is not changed, and the first alignment mark and the second light of the first photoresist layer can be improved. Alignment accuracy of the second alignment mark of the mask. Thereby, the processing accuracy of the etching step is improved, and the yield of the manufacturing step of the piezoelectric vibration element can be improved. Therefore, it is possible to provide a method for manufacturing a piezoelectric vibration element capable of reducing manufacturing costs.

The first photoresist layer 131 may also include a material capable of discoloring the first photoresist layer 131 corresponding to the first pattern PT1 and the first alignment mark MK1 in the first exposure step. For example, the first photoresist layer 131 includes a so-called photoresist color changing material that irradiates light to reversibly change color. According to this, the boundary portion of the first alignment mark in the captured image can be more clearly recognized, and thus the accuracy of alignment can be improved.

Before the steps of forming the first photoresist layer and the second photoresist layer 131 and 132, a first metal layer 121 is formed on the first main surface 111 of the substrate 110, and a first metal layer 121 is formed on the second main surface 112. Two metal layers 122, so that the steps of forming the first photoresist layer and the second photoresist layer 131, 132 may also include forming the first photoresist layer 131 on the first metal layer 121, A step of forming a second photoresist layer 132 on the two metal layers 122. This allows the first and second metal layers to function as an anti-corrosion film in the etching step of the piezoelectric substrate, so that the processing accuracy in the etching step can be improved. In addition, various electrodes can be processed in the first metal layer and the second metal layer.

The first pattern PT1 may be an electrode pattern including a pattern of a first excitation electrode, and the second pattern PT2 may be an electrode pattern including a pattern of a second excitation electrode that faces the first excitation electrode across the piezoelectric substrate. . This improves the accuracy of the relative positions of the first excitation electrode and the second excitation electrode, and can reduce the occurrence rate of defective products in the step of forming the excitation electrode.

The first pattern and the second patterns PT1 and PT2 may be outer shape patterns of the piezoelectric substrate when viewed from the normal direction of the first main surface 111. Applying the manufacturing method of the present embodiment to the formation of the external shape of the piezoelectric substrate can reduce the rate of defective products in the step of etching the substrate to form a collective piezoelectric substrate having a plurality of piezoelectric substrates.

The first pattern and the second patterns PT1 and PT2 may be patterns for changing the thickness of a part of the piezoelectric substrate. According to this, it is possible to reduce the generation rate of defective products in the step of processing the piezoelectric substrate from a flat plate to, for example, a mesa structure.

The first and second alignment marks MK1 and MK2 may be respectively provided at at least two positions. This makes it possible to improve the accuracy of the position adjustment of the entire surface of the substrate when the alignment marks are aligned with each other.

In addition, the method may include a step of forming the substrate 110 into a collective piezoelectric substrate having a plurality of piezoelectric substrates by etching, and a step of separating the piezoelectric substrate from the collective piezoelectric substrate to form a piezoelectric vibration element. The piezoelectric vibration element manufactured through the above steps can suppress the difference in frequency characteristics, and therefore can suppress the occurrence rate of defective products and reduce the manufacturing cost.

Next, a configuration example of a piezoelectric vibrator manufactured using the piezoelectric vibrating element of this embodiment will be described with reference to FIGS. 9 and 10. In the following description, a Quartz Crystal Resonator Unit using a quartz crystal blank as a piezoelectric substrate will be described as an example. Here, FIG. 9 is an exploded perspective view of an example of a piezoelectric vibrator. Fig. 10 is a sectional view taken along the line X-X in Fig. 9.

As shown in FIG. 9, the crystal resonator 1 includes a Quartz Crystal Resonator 10, a cover member 20, and a base member 30. The cover member 20 and the base member 30 are holders for accommodating the crystal resonator element 10. In the example shown in FIG. 9, the cover member 20 has a concave shape, and the base member 30 has a flat plate shape. Conversely, the cover member 20 may have a flat plate shape, and the base member 30 may have a concave shape.

The crystal vibrating element 10 includes an AT-cut quartz crystal blank (Quartz Crystal Blank) 11. The AT-cut quartz crystal 11 rotates the Y-axis and the Z-axis from the Y-axis and Z-axis directions by 35 degrees and 15 minutes among the X-axis, Y-axis, and Z-axis which are crystal axes of the artificial crystal. When the axes of 1 minute and 30 seconds are set to the Y ′ axis and the Z ′ axis, respectively, a plane parallel to a plane specified by the X axis and the Z ′ axis (hereinafter referred to as “XZ ′ plane”) is cut out as the main plane. ). Crystal element 11 'has a rectangular-shaped face having the longitudinal direction of the long sides extending in parallel to the X-axis direction, and Z' in the XZ short-side direction of the short side extends parallel to the axial direction and a thickness parallel to the Y 'axis direction The thickness direction of the extension. The quartz crystal 11 has a first main surface 12a, a second main surface 12b which are XZ ' planes facing each other, and an end surface 12c extending along the short side and connecting the two main surfaces.

A crystal vibrating element using an AT-cut quartz crystal has extremely high frequency stability over a wide temperature range. In addition, it has excellent time-varying characteristics and can be manufactured at low cost. In addition, the AT-cut crystal vibration element uses a Thickness Shear Mode as a main vibration mode. In addition, the cutting angle of the crystal wafer may be applied to a different cutting (for example, BT cutting) other than the AT cutting. In addition, the quartz crystal 11 has a rectangular shape on the XZ ′ plane, but is not limited to this, and may be comb-shaped.

The crystal resonator element 10 includes a first excitation electrode 14 a and a second excitation electrode 14 b constituting a pair of electrodes. The first excitation electrode 14a is provided at a center portion of the first main surface 12a. The second excitation electrode 14b is provided at the center of the second main surface 12b. The first excitation electrode 14 a and the second excitation electrode 14 b are provided so as to face each other via the crystal wafer 11. The first excitation electrode 14a and the second excitation electrode 14b are arranged so as to overlap each other substantially on the XZ ′ plane.

The crystal resonator element 10 includes a pair of extraction electrodes 15a and 15b and a pair of connection electrodes 16a and 16b. The connection electrode 16a is electrically connected to the first excitation electrode 14a via the lead-out electrode 15a. The connection electrode 16b is electrically connected to the second excitation electrode 14b via the lead-out electrode 15b. The connection electrodes 16 a and 16 b are terminals for electrically connecting the first excitation electrode 14 a and the second excitation electrode 14 b to the base member 30. On the first main surface 12a, the first excitation electrode 14a, the extraction electrode 15a, and the connection electrode 16a are continuously provided. In addition, the connection electrode 16a extends over the end surface 12c and the second main surface 12b. This is the same even on the second main surface 12b, and the second excitation electrode 14b, the extraction electrode 15b, and the connection electrode 16b are continuously provided. In addition, the connection electrode 16b extends over the end surface 12c and the first main surface 12a. In the configuration example shown in FIG. 7, the connecting electrodes 16a and 16b in the short side direction of the crystal piece 11 (Z 'axis direction). The connection electrodes 16 a and 16 b may be arranged along the longitudinal direction (X-axis direction) of the quartz crystal 11. In addition, the connection electrodes 16 a and 16 b may be disposed near the center of the long side or the short side of the crystal piece 11, or may be disposed on the other sides of the crystal piece 11.

The conductive holding members 36a and 36b are electrically connected to the connection electrodes 16a and 16b on a pair of electrode pads of the base member 30, respectively. The conductive holding members 36a and 36b are formed of a conductive adhesive such as an ultraviolet curable resin. The conductive holding member 36a is in contact with the connection electrode 16a of the second main surface 12b and the end surface 12c, for example. The same applies to the conductive holding member 36b. By increasing the contact area between the conductive holding member and the connection electrode, the conductivity of the electrode pad and the connection electrode can be improved.

The lid member 20 is joined to the base member 30, and thereby the crystal resonator element 10 is accommodated in the internal space 26. The cover member 20 has an inner surface 24 and an outer surface 25, and has a concave shape that opens toward the third main surface 32 a of the base member 30. The cover member 20 has a top surface portion 21 opposed to the third main surface 32 a of the base member 30, and a side wall portion 22 connected to an outer edge of the top surface portion 21 and extending in a direction crossing the main surface of the top surface portion 21. The cover member 20 has, at the concave opening edge (the end face of the side wall portion 22), an opposing surface 23 that opposes the third main surface 32a of the base member 30, and the opposing surface 23 extends in a frame shape so as to surround the crystal resonator element 10 around.

The base member 30 supports the crystal resonator element 10 so as to be able to excite. Specifically, the crystal resonator element 10 is held on the third main surface 32a of the base member 30 via the conductive holding members 36a and 36b so as to be able to be excited. The base member 30 includes a base 31. The base body 31 has a third main surface 32a and a fourth main surface 32b which are XZ ' planes facing each other. The base 31 is a sintered material such as an insulating ceramic (alumina).

The base member 30 includes electrode pads 33a and 33b provided on the third main surface 32a and external electrodes 35a, 35b, 35c, and 35d provided on the second main surface. The electrode pads 33 a and 33 b are terminals for electrically connecting the base member 30 and the crystal resonator element 10. The external electrodes 35a, 35b, 35c, and 35d are terminals for electrically connecting a mounting substrate (not shown) and the quartz crystal resonator 1. The electrode pad 33a is electrically connected to the external electrode 35a via a conductive electrode 34a extending in the Y ′ axis direction, and the electrode pad 33b is electrically connected to the external electrode 35b via a conductive electrode 34b extending in the Y ′ axis direction. The conductive electrodes 34 a and 34 b are formed in through holes that penetrate the base body 31 in the Y ′ axis direction.

The electrode pads 33 a and 33 b of the base member 30 are provided on the third main surface 32 a near the short side on the negative side of the X axis of the base member 30, and are spaced apart from the short side of the base member 30 and arranged along the short side direction. The electrode pad 33a is connected to the connection electrode 16a of the crystal resonator element 10 via a conductive holding member 36a, and the electrode pad 33b is connected to the connection electrode 16b of the crystal resonator element 10 via a conductive holding member 36b.

The plurality of external electrodes 35a, 35b, 35c, and 35d are provided near each corner of the fourth main surface 32b. For example, the external electrodes 35a and 35b are arranged immediately below the electrode pads 33a and 33b. Thus, the external electrodes 35a and 35b can be electrically connected to the electrode pads 33a and 33b by the conductive electrodes 34a and 34b extending in the Y ′ axis direction. Among the four external electrodes 35 a to 35 d, the external electrodes 35 a and 35 b arranged near the short side on the negative side of the X-axis of the base member 30 are input and output electrodes that supply input and output signals of the crystal resonator element 10. In addition, the external electrodes 35 c and 35 d disposed near the short side on the X-axis positive direction side of the base member 30 are virtual electrodes that do not supply input and output signals of the crystal resonator element 10. Input and output signals are not supplied to the above-mentioned virtual electrodes to other electronic components on a mounting substrate (not shown) on which the crystal oscillator 1 is mounted. Alternatively, the external electrodes 35c and 35d may be ground electrodes that supply a ground potential. When the cover member 20 is made of a conductive material, the cover member 20 is connected to the external electrodes 35 c and 35 d which are electrodes for grounding, thereby adding a cover function to the cover member 20.

A sealing frame 37 is provided on the third main surface 32 a of the base body 31. For example, the sealing frame 37 has a rectangular frame shape in plan view from the normal direction of the third main surface 32a. In addition, the electrode pads 33 a and 33 b are arranged inside the sealing frame 37, and the sealing frame 37 is provided so as to surround the crystal resonator element 10. The sealing frame 37 is made of a conductive material. The sealing member 37 is provided with a bonding member 40 described later, whereby the cover member 20 is bonded to the base member 30 via the bonding member 40 and the sealing frame 37. For example, the electrode pads 33a and 33b of the base member 30, the external electrodes 35a to 35d, and the sealing frame 37 are all made of a metal film. The metal film is configured, for example, from a side (lower layer) close to the substrate 31 to a separated side (upper layer), and a molybdenum (Mo) layer, a nickel (Ni) layer, and a gold (Au) layer are laminated in this order. The via electrodes 34 a and 34 b can be formed by filling a through hole of the base 31 with a metal material such as molybdenum (Mo).

Both the lid member 20 and the base member 30 are joined via the sealing frame 37 and the joint member 40, so that the crystal resonator element 10 is sealed in an internal space (cavity) 26 surrounded by the lid member 20 and the base member 30. In this case, it is preferable that the pressure of the internal space 26 is a vacuum state lower than the atmospheric pressure, so that the process of the frequency characteristics of the crystal oscillator 1 due to the oxidation of the first excitation electrode 14a and the second excitation electrode 14b can be reduced. Change over time.

The joining member 40 is provided all over the entire periphery of the cover member 20 and the base member 30. Specifically, the bonding member 40 is provided on the sealing frame 37. The sealing frame 37 and the joint member 40 are sandwiched between the facing surface 23 of the side wall portion 22 of the cover member 20 and the third main surface 32 a of the base member 30, whereby the crystal resonator element 10 is sealed by the cover member 20 and the base member 30. .

In the crystal resonator element 10 of this configuration example, one end (the end portion on the side where the conductive holding members 36a, 36b is disposed) of the quartz crystal 11 in the longitudinal direction is a fixed end, and the other end is a free end. In addition, the crystal resonator element 10, the cover member 20, and the base member 30 have rectangular shapes in the XZ ' plane, and the long-side direction and the short-side direction are the same as each other.

However, the position of the fixed end of the crystal resonator element 10 is not particularly limited, and may be fixed to the base member 30 at both ends in the longitudinal direction of the quartz crystal 11. In this case, the electrodes of the crystal resonator element 10 and the base member 30 may be formed so that the crystal resonator element 10 is fixed to both ends in the longitudinal direction of the quartz plate 11.

In the crystal oscillator 1 of this configuration example, an alternating current electric field is applied between the pair of excitation electrodes 14 a and 14 b of the crystal resonator element 10 via the external electrodes 35 a and 35 b of the base member 30. Thereby, the quartz crystal 11 is vibrated by a predetermined vibration mode such as a thickness-shear vibration mode, and a resonance characteristic accompanying the vibration is obtained.

In the case of manufacturing the above-mentioned crystal oscillator, by using the crystal vibration element to which the manufacturing method of the present embodiment is applied, it is possible to suppress the difference in performance of the crystal oscillator by improving the processing accuracy of the crystal vibration element.

Next, a modification of the piezoelectric vibrator will be described. In the following modification examples, descriptions of cases common to the above-mentioned embodiment are omitted, and only differences will be described. In particular, the same effects provided by the same configuration are not described in order.

<Modifications>

FIG. 11 is a perspective view of a piezoelectric vibration element according to a modification. The modification is different from the configuration example shown in FIG. 9 in that the shape of the piezoelectric vibration element 210 is a tuning fork type. Specifically, the piezoelectric substrate 211 has two tuning fork arm portions 219a and 219b arranged in parallel with each other. Tuning fork arm portions 219a, 219b extending in the X-axis direction, and side by side in the Z 'axis direction, and is connected to the end face 212c-side portion 219c connected to each other. In the tuning fork arm portion 219a, excitation electrodes 214a are respectively provided on a pair of main surfaces parallel to the XZ ' plane and facing each other, and a pair of side end surfaces that cross the pair of main surfaces and face each other are respectively provided Excitation electrode 214b. In the tuning fork arm portion 219b, an excitation electrode 214b is provided on each of a pair of main surfaces, and an excitation electrode 214a is provided on each of a pair of side end surfaces. In addition, the configuration of the piezoelectric vibration element 210 is not particularly limited, and the shape of the tuning fork arm portion, the arrangement of the excitation electrodes, and the like may be different.

Even in the above modification, the same effects as those described above can be obtained.

The embodiments described above are used to facilitate understanding of the present invention, and are not to be construed as limiting the present invention. The present invention can be changed / improved without departing from the gist thereof, and the present invention includes equivalents thereof. In other words, those skilled in the art can appropriately design changes to each of the embodiments as long as they have the features of the present invention, and are included in the scope of the present invention. For example, each element provided in each embodiment and its arrangement, material, conditions, shape, size, and the like are not limited to the illustrated examples, and can be appropriately changed. In addition, each element provided in each embodiment can be technically combined as much as possible, and a technical solution combining these elements is also included in the scope of the present invention as long as the features of the present invention are included.

Claims (9)

    A method for manufacturing a piezoelectric vibration element, comprising: preparing a substrate having a first main surface and a second main surface facing the first main surface and having piezoelectricity; and Forming a first photoresist layer on the first main surface side, and forming a second photoresist layer on the second main surface side; exposing the first photoresist layer using the first photomask, and A first exposure step of transferring a first pattern and a first alignment mark on the first photoresist resist layer; shooting a second alignment mark of a second photomask, and recording a photograph of the captured image of the second alignment mark. Step; a step of adjusting a relative position on the substrate with respect to the second photomask based on the captured image of the first alignment mark and the second alignment mark of the first photoresist layer; using the first Two photomasks, a second exposure step of exposing the second photoresist layer and transferring a second pattern on the second photoresist layer; and making the first photoresist layer and the second photoresist layer Resist layer development Step.         For example, the method for manufacturing a piezoelectric vibration element according to claim 1 in which the first photoresist layer includes the first photoresist layer corresponding to the first pattern and the first exposure step. The first alignment mark discolors the material.         For example, the method for manufacturing a piezoelectric vibration element according to item 2 of the application, wherein the first photoresist etchant layer includes a photoresistive color changing material.         The method for manufacturing a piezoelectric vibration element according to any one of claims 1 to 3, wherein before the step of forming the first photoresist layer and the second photoresist layer, the substrate is formed on the substrate. The step of forming a first metal layer on the first main surface, forming a second metal layer on the second main surface, and forming the first photoresist layer and the second photoresist layer includes the steps of Forming a first photoresist layer on a metal layer and forming the second photoresist layer on the second metal layer.         For example, the method of manufacturing a piezoelectric vibration element according to item 4 of the patent application, wherein the first pattern is an electrode pattern including a pattern of a first excitation electrode, and the second pattern is a pattern including the first pattern through a piezoelectric substrate and the first pattern. An electrode pattern of the pattern of the second excitation electrode facing the excitation electrode.         The method for manufacturing a piezoelectric vibration element according to any one of claims 1 to 3, wherein the first pattern and the second pattern are piezoelectric when viewed from above the normal direction of the first main surface. The outline pattern of the substrate.         According to the method for manufacturing a piezoelectric vibration element according to any one of claims 1 to 3, the first pattern and the second pattern are patterns for changing a thickness of a part of the piezoelectric substrate.         According to the method for manufacturing a piezoelectric vibration element according to any one of claims 1 to 3, the first alignment mark and the second alignment mark are respectively provided at at least two positions.         The method for manufacturing a piezoelectric vibration element according to any one of claims 1 to 3, further comprising: a step of forming the substrate into an aggregate piezoelectric substrate having a plurality of piezoelectric substrates by etching; and A step of separating the piezoelectric substrate from the collective piezoelectric substrate to form a piezoelectric vibration element.