JP2014110490A - Method for manufacturing crystal wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture a crystal piece with two types of thickness.SOLUTION: A method for manufacturing a crystal wafer 10 is provided, in which a crystal piece 1 having an oscillation part 2 and a support part 3 is formed on a planar crystal plate 4. The method comprises: a first mask step of superposing a first mask 20 having an outline pattern 21 corresponding to a part to be a crystal piece on one chief surface of a crystal plate where a photoresist is applied; a second mask step of superposing a second mask 30 having an oscillation part pattern 31 corresponding to an oscillation part of the crystal piece on the other chief surface of the crystal plate where a photoresist R is applied; an exposure step of exposing the crystal plate while the first mask and the second mask are superposed; a pattern forming step of forming the oscillation part pattern on the other chief surface of the crystal plate while forming the outline pattern on one chief surface of the crystal plate; and a wet etching step of wet etching the crystal plate on which the outline pattern and the oscillation part pattern are formed.

Description

  The present invention relates to a method of manufacturing a quartz wafer provided with a quartz piece used for a quartz device.

Conventionally, a quartz crystal element in which a quartz film is provided with a metal film is used for a quartz crystal device.
This crystal piece can be formed by etching an AT-cut crystal wafer.
An AT-cut quartz wafer is a plate material obtained by cutting an artificial quartz crystal. Of the X-axis, Y-axis, and Z-axis that are crystal axes of the quartz, the surface facing the Y-axis side is θ ° around the X-axis. Of the X-axis, Y′-axis, and Z′-axis that are newly set by rotation, the surface that faces the Y-axis is cut in a state that faces the Y′-axis.
The cut quartz wafer has a surface polished and finished to a predetermined thickness T.
In the case of providing a plurality of crystal pieces on such a crystal wafer, a method of manufacturing a crystal piece that uses a photolithography technique and an etching technique so that the thickness of the crystal piece becomes thinner than the thickness of the edge part of the crystal wafer. Has been proposed (see, for example, Patent Document 1). Thereby, damage to the crystal wafer can be reduced.
In addition, a quartz wafer is manufactured by forming a groove having a predetermined width while polishing the quartz wafer with a lapping bar to provide a vibrating part and a supporting part. A method for producing a crystal piece including a vibrating part and a support part by cutting the part is disclosed (for example, see Patent Document 2).

JP 2011-078118 A JP 2001-144578 A

However, a conventionally proposed method for manufacturing a quartz wafer is configured such that a quartz wafer having a support portion that is thicker than a portion that becomes a vibrating portion is formed on the quartz wafer. There is a possibility that a photoresist pool will be generated at the boundary between the crystal part and the part that becomes the crystal piece, and the exposure for forming the element shape may be incomplete.
Further, when a crystal piece including a vibrating portion and a support portion having a thickness larger than that is formed using the crystal wafer proposed in Patent Document 1, the edge portion of the crystal wafer is further formed than the support portion of the crystal piece. Due to the thickness, there is a concern that the space between the vibrating part of the crystal piece and the mask is widened and it becomes difficult to form a fine pattern.
In addition, since the quartz wafer proposed in Patent Document 2 forms a vibrating portion using polishing, there is a possibility that the portion that becomes the vibrating portion of the crystal piece is damaged during polishing.

  Therefore, an object of the present invention is to provide a crystal wafer that solves the above-described problems, prevents damage to the crystal piece, and can easily manufacture the crystal piece.

  In order to solve the above-mentioned problems, the present invention is a method for manufacturing a crystal wafer in which a crystal piece having a vibration part and a support part thicker than the vibration part is formed on a plate-like crystal plate having a predetermined thickness. A first mask step of superimposing a first mask formed with an external pattern corresponding to a portion to be the crystal piece on one main surface of the crystal plate provided with a photoresist on the corrosion-resistant film; A second mask step of superposing a second mask on which a vibration part pattern corresponding to a part to be a vibration part of the crystal piece is formed on the other main surface of the crystal plate on which a photoresist is provided on a film; An exposure step of exposing the photoresist in a state where the first mask and the second mask are superimposed on the quartz plate, and the quartz plate while forming an external pattern so that one main surface of the quartz plate is exposed. The other lord of A pattern forming step of forming a vibration part pattern so as to be exposed, and a wet etching step of wet etching the crystal plate in a state where the outer shape pattern and the vibration part pattern are formed. And

  Further, the present invention is a method for manufacturing a quartz wafer in which a quartz piece including a vibrating portion and a support portion having a thickness larger than the vibrating portion is formed on a plate-like quartz plate having a predetermined thickness, Corresponding to the portion that becomes the crystal piece on one main surface of the crystal plate on which the photoresist is provided on the corrosion-resistant film so that the vibration part of the crystal piece is arranged adjacent to the crystal wafer A first mask step of overlaying a first mask on which an outer shape pattern is formed, and a portion serving as a vibrating portion of the crystal piece on the other main surface of the crystal plate provided with a photoresist on a corrosion-resistant film. A second mask step of superimposing a second mask on which a vibration part pattern is formed; and the vibration part pattern is formed so as to expose the vibration parts adjacent to each other, and the first mask and the second mask are formed on the crystal plate. And overlaid And an exposure step of exposing the photoresist, and forming a vibration part pattern so that the other principal surface of the quartz plate is exposed while forming an outer shape pattern so that one principal surface of the quartz plate is exposed. It is characterized by including a pattern formation process and a wet etching process in which the crystal plate is wet-etched in a state where the outer shape pattern and the vibration part pattern are formed.

  According to such a method for manufacturing a quartz wafer, an outer pattern corresponding to a portion to be the quartz piece is formed on one main surface of the quartz plate provided with a photoresist on a corrosion-resistant film. A first mask step of overlaying a mask, and a vibration part pattern corresponding to a part to be a vibration part of the crystal piece on the other main surface of the crystal plate on which the photoresist is provided on the corrosion-resistant film. A pattern forming step of forming an oscillating portion pattern on the other main surface of the crystal plate while performing an exposure step and forming an external pattern on one main surface of the crystal plate. By performing the wet etching process after the process, the crystal shape and the vibration part can be formed at the same time, and the crystal piece is connected to the crystal wafer, so the crystal piece is highly productive. , It is possible to reduce the risk of damage.

  Further, according to such a method of manufacturing a quartz wafer, the vibrating portions of the plurality of quartz pieces are adjacent to each other in the quartz wafer on one main surface of the quartz plate in which a photoresist is provided on the corrosion-resistant film. A first mask step of overlaying a first mask formed with an outer shape pattern corresponding to a portion to be the crystal piece so as to be disposed, and the other of the crystal plate provided with a photoresist on a corrosion-resistant film Performing a second mask step of overlaying a second mask on which a vibrating portion pattern corresponding to a portion to be a vibrating portion of the quartz crystal piece is exposed so that the vibrating portion is exposed on the main surface, and performing an exposure step And performing a wet etching process after performing a pattern forming process for forming a vibration part pattern on the other main surface of the crystal plate while forming an outer shape pattern on one main surface of the crystal plate. Shape and the can at the same time forming the vibrating portion, and because the crystal piece is formed while connected to the crystal wafer, it is possible productivity of crystal blank well, to reduce the risk of damage.

(A) is a fragmentary sectional view which shows an example of the state which provided the corrosion-resistant film | membrane and the photoresist in the quartz plate, (b) is a fragmentary sectional view which shows the state which accumulated the 1st mask, (c) is the 1st. It is the fragmentary sectional view which shows the state which piled up two masks, (d) is a fragmentary sectional view which shows an example of the state which developed the photoresist, (e) shows an example of the state which carried out the wet etching of the corrosion-resistant film | membrane. It is a fragmentary sectional view, (f) is a fragmentary sectional view which shows the state where the 1st mask and the 2nd mask were removed, and (g) is a fragmentary sectional view which shows an example in the state where the quartz plate was wet-etched (H) is a fragmentary sectional view which shows an example of the quartz wafer from which the photoresist and the corrosion-resistant film were removed. (A) is a partial top view which shows an example of a 1st mask, (b) is a partial top view which shows an example of a 2nd mask. It is a fragmentary perspective view which shows an example of a quartz wafer. It is a perspective view which shows an example of a crystal piece.

  Next, the best mode for carrying out the present invention (hereinafter referred to as “embodiment”) will be described in detail with reference to the drawings as appropriate. Note that each component is exaggerated for easy understanding of the state.

(Crystal wafer)
First, a quartz wafer will be described.
As shown in FIG. 3, the crystal wafer 10 is formed from, for example, an AT-cut plate-like crystal plate 4 having a predetermined thickness, and the outer shape in plan view is a square shape or a circular shape. In the present embodiment, a rectangular crystal plate will be described. The crystal wafer 10 is provided with a plurality of crystal pieces 1. As shown in FIG. 4, the crystal piece 1 includes a vibrating portion 2 and a support portion 3 having a thickness greater than that of the vibrating portion 2. The plurality of crystal pieces 1 configured as described above are formed such that the vibrating portions 2 are arranged adjacent to each other in the crystal wafer 10, and the support portion 3 and the crystal plate 4 are connected. .

(Quartz wafer manufacturing method)
Next, a method for manufacturing a quartz wafer will be described.
The crystal wafer manufacturing method according to the embodiment of the present invention includes a first mask process, a second mask process, an exposure process, a pattern formation process, and a wet etching process.

First, a crystal plate formed in a plate shape is formed to a predetermined thickness.
As shown in FIG. 1A, the quartz plate 4 is provided with a corrosion resistant film T. The corrosion resistant film T can be provided on the quartz plate 4 by using, for example, a vapor deposition technique or a sputtering technique.
A photoresist R is provided on the corrosion resistant film T. The photoresist R can be provided on the corrosion-resistant film T provided on the quartz plate 4 by using, for example, a spin coater.

In the first mask process, as shown in FIG. 1B, an external pattern corresponding to a portion that becomes the crystal piece 1 on one main surface of the crystal plate 4 provided with the photoresist R on the corrosion-resistant film T. This is a step of superposing the first mask 20 on which 21 (see FIG. 2A) is formed.
In the first mask process, first, the first mask 20 is superposed on one main surface of the crystal plate 4 with the photoresist R provided on the crystal plate 4. The first mask 20 has a portion penetrating in correspondence with the outer shape of the plurality of crystal pieces 1 formed on the crystal wafer 10. This penetration part becomes the outer shape pattern 21. For example, the first mask 20 is formed in a state in which the connection portion between the crystal piece 4 and the crystal wafer 10 is blocked, and the portion between the adjacent crystal pieces 1 and the portion not connected to the crystal plate 4 penetrates. Yes.

As shown in FIG. 1C, the second mask process corresponds to a portion that becomes the vibrating portion 2 of the crystal piece 1 on the other main surface of the crystal plate 4 on which the photoresist R is provided on the corrosion-resistant film T. In this step, the second mask 30 on which the vibration part pattern 31 is formed is overlapped.
In the second mask process, the second mask 30 is superimposed on the other main surface of the crystal plate 4 with the photoresist R provided on the crystal plate 4. As shown in FIG. 2B, the second mask 30 has a portion that penetrates in correspondence with a portion that becomes the vibrating portion 2 of the crystal piece 1. This penetrating part is the vibration part pattern 31. For example, the second mask 30 is formed in a state where a portion to be the vibrating portion 2 of the crystal piece 1 is penetrated. Further, the second mask 30 is formed with a penetrating portion so as to expose the adjacent vibrating portions 2 together. In addition, in the part which becomes the support part 3, the linear penetration part 32 is formed so that the groove | channel for making a cleaving easily may be formed in the boundary of the part which becomes the adjacent support part 3 at the time of individual change. Also good.

The exposure step is a step of exposing the photoresist R with the first mask and the second mask superimposed on the quartz plate 4.
In the exposure step, the photoresist R is exposed in a state where the first mask and the second mask are superimposed on the quartz plate 4 to change, for example, the exposed portion of the photoresist.
For the exposure, for example, an exposure apparatus capable of double-sided exposure may be used. When an exposure apparatus capable of single-sided exposure is used, the quartz plate 4 may be exposed separately for each side.

In the pattern forming step, as shown in FIGS. 1D and 1E, the external pattern 21 is formed so that one main surface of the crystal plate 4 is exposed, and the other main surface of the crystal plate 4 is formed. This is a step of forming the vibration part pattern 31 so as to be exposed.
In the pattern forming process, first, for example, development is performed on the photoresist R exposed in the exposure process to expose the corrosion-resistant film T provided on the quartz plate 4 (see FIG. 1D), and then the exposed corrosion-resistant film is formed. The film T is removed by wet etching to expose the surface of the crystal plate 4 (see FIG. 1E).
Thereby, the surface of the crystal plate 4 is exposed with the outer shape pattern 21 corresponding to the outer shape of the crystal piece 1, and the surface of the crystal plate 4 is exposed including the vibrating portion pattern 31 corresponding to the portion to be the vibrating portion 2. It becomes.
Here, the vibration part pattern 31 is formed so as to expose the surface of the quartz crystal plate 4 at the part that becomes the adjacent vibration part 3 in a lump.

  As shown in FIG. 1 (f), the first mask and the second mask superimposed on the crystal plate 4 are removed, and the crystal plate 4 provided with the outer shape pattern 21 and the vibration part pattern 31 is obtained.

As shown in FIG. 1G, the wet etching step is a step of wet etching the crystal plate 4 in a state where the outer shape pattern 21 and the vibration part pattern 31 are formed.
In the wet etching process, wet etching is performed on the crystal plate 4 on which the outer shape pattern 21 and the vibration portion pattern 31 are formed, and the formation of the outer shape of the crystal piece 1 and the vibration portion 2 and the support portion 3 are simultaneously performed. Form.
Thereby, the crystal plate 1 having the vibration part 2 and the support part 3 is provided on the crystal plate 4.

  As shown in FIG. 1 (h), after the wet etching process is performed, the photoresist R is peeled off and provided on the crystal plate 4 in a state where the crystal pieces 1 are formed on the crystal plate 4. The photoresist R is peeled off to expose the corrosion-resistant film T, and the exposed corrosion-resistant film T is subjected to wet etching to remove the corrosion-resistant film T provided on the crystal plate 4.

  Thereby, it is possible to manufacture a crystal wafer 10 on which a plurality of crystal pieces 1 each including the vibration part 2 and the support part 3 having a thickness larger than the vibration part 2 are formed.

  Therefore, in the method for manufacturing a crystal wafer according to the embodiment of the present invention, the vibrating portions 2 of the plurality of crystal pieces 1 are formed on the crystal plate 4 on one main surface of the crystal plate 4 on which the photoresist R is provided on the corrosion-resistant film T. 4, a first mask step of overlaying a first mask 20 formed with an outer shape pattern 21 corresponding to a portion to be the crystal piece 1 so as to be arranged adjacent to each other in the crystal piece 1, and a photoresist R on the corrosion resistant film T A second mask 30 on which a vibration part pattern 31 corresponding to a part to be the vibration part 2 of the crystal piece 1 is formed so as to expose the vibration part 2 collectively on the other main surface of the provided crystal plate 4 is provided. A pattern forming step of forming an oscillating portion pattern 31 on the other main surface of the crystal plate 4 while performing an exposure step and forming an external pattern 21 on one main surface of the crystal plate 4 After wet By performing the chucking process, the outer shape of the crystal piece 1 and the vibration part 2 can be formed simultaneously, and since the crystal piece 1 is formed in a state of being connected to the crystal plate 4, the productivity of the crystal piece 1 is good. The risk of damage can be reduced.

In addition, the manufacturing method of the crystal wafer of this invention is not limited to this embodiment, It can change suitably. For example, it goes without saying that either positive or negative photoresist is used.
Moreover, you may form a vibration part pattern corresponding to each shape of the part used as the vibration part of a crystal piece.
Moreover, it is good also as a structure which provided the penetration part separately between the vibration part 2 and the support part 3 of the crystal piece 1. In this case, the penetrating portion can be formed by forming a penetrating portion having a shape corresponding to the penetrating portion in the first mask and the second mask.

DESCRIPTION OF SYMBOLS 10 Quartz wafer 1 Quartz piece 2 Vibrating part 3 Supporting part 4 Quartz plate 20 First mask 21 External pattern 30 Second mask 31 Vibrating part pattern T Corrosion-resistant film R Photoresist

Claims (2)

A method for producing a crystal wafer in which a crystal piece comprising a vibration part and a support part having a thickness greater than the vibration part is formed on a plate-like crystal plate having a predetermined thickness,
A first mask step of superimposing a first mask on which an external pattern corresponding to a portion to be the crystal piece is formed on one main surface of the crystal plate provided with a photoresist on a corrosion-resistant film;
A second mask step of superimposing a second mask on which a vibration part pattern corresponding to a part to be a vibration part of the crystal piece is formed on the other main surface of the crystal plate on which a photoresist is provided on a corrosion-resistant film; ,
An exposure step of exposing the photoresist with the first mask and the second mask overlaid on the quartz plate;
A pattern forming step of forming a vibrating portion pattern so that the other main surface of the crystal plate is exposed while forming an outer shape pattern so that one main surface of the crystal plate is exposed;
A method for manufacturing a crystal wafer, comprising: a wet etching step of performing wet etching on the crystal plate in a state where the outer shape pattern and the vibration part pattern are formed. A method for producing a crystal wafer in which a crystal piece comprising a vibration part and a support part having a thickness greater than the vibration part is formed on a plate-like crystal plate having a predetermined thickness,
In such a manner that the vibrating portions of the plurality of crystal pieces are arranged adjacent to each other in a crystal wafer,
A first mask step of superimposing a first mask on which an external pattern corresponding to a portion to be the crystal piece is formed on one main surface of the crystal plate provided with a photoresist on a corrosion-resistant film;
A second mask step of superimposing a second mask on which a vibration part pattern corresponding to a part to be a vibration part of the crystal piece is formed on the other main surface of the crystal plate on which a photoresist is provided on a corrosion-resistant film; ,
The vibration part pattern is formed so as to expose the vibration parts adjacent to each other,
An exposure step of exposing the photoresist with the first mask and the second mask overlaid on the quartz plate;
A pattern forming step of forming a vibrating portion pattern so that the other main surface of the crystal plate is exposed while forming an outer shape pattern so that one main surface of the crystal plate is exposed;
A method for manufacturing a crystal wafer, comprising: a wet etching step of performing wet etching on the crystal plate in a state where the outer shape pattern and the vibration part pattern are formed.

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