JP6158501B2 - Method for manufacturing crystal piece - Google Patents

Description

  The present invention relates to a method for manufacturing a crystal piece used in a crystal 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 wet-etching an AT-cut crystal wafer. An AT-cut quartz wafer is a plate material provided by cutting an artificial quartz crystal, and of the X-axis, Y-axis, and Z-axis that are crystal axes of the crystal, a surface facing the Y-axis side is a predetermined axis around the X-axis. It is obtained by cutting so as to form surfaces that are rotated at an angle and face newly set X axis, Y ′ axis, and Z ′ axis.
The cut quartz wafer has a surface polished to a predetermined thickness.
As shown in FIGS. 5A to 5G, such a crystal wafer W is provided with masks M1, M2 having a predetermined pattern corresponding to the shape of the crystal piece 10 on both main surfaces. A position other than the position of the outer peripheral frame and the outer frame is opened.
By performing wet etching in this state, a plurality of crystal pieces 10 can be manufactured from the crystal wafer W (see, for example, Patent Document 1).

JP-A-1-179513

However, when the AT-cut quartz crystal wafer W is wet-etched, as shown in FIGS. 5H to 5I, the stripe 11 is formed on the side surface formed so as to be parallel to the X axis of the quartz crystal piece 10. was there.
This is presumed to occur because the masks M1 and M2 provided on the crystal wafer W are not parallel to the X axis.
For example, in the pattern of the masks M1 and M2, in the portion parallel to the X axis of the crystal piece 10, the portion parallel to the X axis is rotated at a predetermined angle with respect to the X axis, and the crystal wafer W May be in a state of being provided.
When wet etching is performed in this state, a substantially V-shaped streak is generated on the side surface that should be parallel to the X axis of the manufactured crystal piece.
Such a crystal piece tends to deteriorate the CI (crystal impedance) value.

  Accordingly, the present invention aims to solve the above-described problems and to provide a method for manufacturing a crystal piece that prevents the occurrence of a substantially V-shaped stripe 11 on the side face of the crystal piece and prevents the CI value from deteriorating. .

In order to solve the above-mentioned problems, the present invention is set by rotating a surface facing the Y-axis side from a crystal having X-axis, Y-axis, and Z-axis crystal axes at a predetermined angle around the X-axis. After forming a patterned anti- corrosion film and a mask made of photoresist on the main surface of an AT-cut quartz wafer on which the surfaces facing the X-axis, Y'-axis, and Z'-axis are formed, wet etching is performed to form a plate A method of manufacturing a crystal piece for forming a crystal piece of
The orientation of the mask, the X axis about the Y 'axis, 0 ° <θ <+ 0.5 ° or, -0.5 ° <θ <to be in the range of 0 °, the X-axis and the Z A plurality of crystal pieces are formed by performing wet etching in this state on both main surfaces of a crystal wafer parallel to the 'axis.

  In such a method for manufacturing a crystal piece, the orientation of the mask corresponding to the shape of the crystal piece is 0 ° <θ <+ 0.5 ° or −0.5 ° <θ <0 ° with respect to the X axis. Since the crystal wafers are provided on both main surfaces of the crystal wafer so as to satisfy the above range, substantially V-shaped streaks do not occur on the side surfaces parallel to the X axis of the crystal piece, and the deterioration of the CI value due to the streaks can be prevented. .

It is a conceptual diagram which shows an example of the state of the crystal piece which concerns on embodiment of this invention. It is a graph which shows the relationship between the temperature and CI value in the crystal piece manufactured with the manufacturing method of the crystal piece of this invention. It is a graph which shows the relationship between the temperature of a crystal piece manufactured with the manufacturing method of the conventional crystal piece, and CI value. It is a conceptual diagram which shows the other example of the state of the crystal piece which concerns on embodiment of this invention. It is a conceptual diagram which shows the manufacturing method of the conventional quartz 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.

(First embodiment)
The method for manufacturing a crystal piece according to the first embodiment of the present invention is a method for manufacturing a crystal piece by performing wet etching from an AT-cut crystal wafer.

First, a quartz wafer will be described.
As described above, an AT-cut quartz wafer is a plate material provided by cutting artificial quartz. For example, an AT-cut crystal wafer is newly set by rotating a surface facing the Y-axis side at a predetermined angle around the X-axis on the X-axis, Y-axis, and Z-axis that are crystal axes of the crystal. , Obtained by cutting so as to form a surface facing the Y ′ axis and the Z ′ axis. The cut quartz wafer has a surface polished to a predetermined thickness. Hereinafter, an AT-cut quartz wafer is simply referred to as a “quartz wafer”.
A plane parallel to the X axis and the Z ′ axis is a main surface.

Next, the crystal piece will be described.
For example, as shown in FIG. 1, the crystal piece is formed to be a rectangular flat plate in plan view. Further, this crystal piece is formed, for example, such that the short side faces the X-axis side and the long side faces the Z′-axis side.

Here, the manufacturing method of a crystal piece is demonstrated.
First, a corrosion resistant film is provided on both main surfaces of the quartz wafer, and then a photoresist is provided on the corrosion resistant film.
The photoresist is exposed so that a pattern corresponding to the outer shape of the crystal piece is formed, development is performed to remove unnecessary photoresist, and patterning is performed to remove the corrosion-resistant film. This patterning is performed, for example, by wet etching using an etchant that does not dissolve the photoresist and the quartz wafer.
A state in which the anti-corrosion film is patterned in this manner and a photoresist is provided on the anti-corrosion film is referred to as a “mask”.
The portion of the pattern formed by removing the corrosion-resistant film is in a state where the surface of the crystal wafer is exposed (see, for example, FIGS. 5A to 5E).

At this time, in the pattern formed by removing the corrosion-resistant film, the side surface facing the Z′-axis side is provided by being rotated by an angle θ satisfying 0 ° <θ <+ 0.5 ° with respect to the X-axis. (See FIG. 1).
In this state of patterning, wet etching is performed using an etchant that melts crystal.
Thereby, the several crystal piece 10 can be manufactured from a crystal wafer.

  Here, when the angle is 0 °, it means that the mask is manufactured in a state where the mask is provided on the crystal wafer W as designed.

When the angle θ is 0.5 ° or more, a substantially V-shaped streak is generated on the side surface in the longitudinal direction of the crystal piece 10. This is because when the angle θ is θ ≧ + 0.5 °, a large number of crystal planes that are not parallel to the X axis are generated on the side surface on the long side of the crystal piece, and stripe-like patterns appear on the side surface. is there.
However, when the angle θ is 0 ° <θ <+ 0.5 °, a substantially V-shaped streak that has conventionally occurred on the side surface in the longitudinal direction of the crystal piece 10 can be prevented.
This is because when the angle θ is 0 ° <θ <+ 0.5 °, a stripe-like pattern does not appear because a crystal plane parallel to the X axis appears on the side surface on the long side.

  Here, when comparing the relationship between the temperature and CI value of the crystal piece manufactured by the conventional manufacturing method and the crystal piece manufactured by the manufacturing method of the present invention in a graph, first, as shown in FIG. The crystal piece manufactured by the manufacturing method has a CI value within a temperature range of −40 ° C. to 100 ° C., and the CI value is within 40Ω to 60Ω, and has a small variation in the temperature range. It was confirmed that the crystal piece manufactured by the method changed in a similar temperature range, particularly in the range of 40 ° C. to 100 ° C., and the CI value was deteriorated.

  Therefore, since the method for manufacturing a crystal piece according to the present invention is configured as described above, a substantially V-shaped streak does not occur on the side surface facing the Z′-axis direction of the crystal piece, and the CI value can be prevented from deteriorating. .

(Second embodiment)
A method for manufacturing a crystal piece according to the second embodiment of the present invention will be described.
In the method for manufacturing a crystal piece according to the second embodiment of the present invention, in the pattern formed by removing the corrosion-resistant film, the side surface facing the Z-axis side is −0.5 ° <θ <with respect to the X-axis. It differs from the first embodiment in that it is provided by being rotated by an angle θ that becomes 0 °.

A method for manufacturing a crystal piece according to the second embodiment of the present invention will be described.
First, a corrosion resistant film is provided on both main surfaces of the quartz wafer, and then a photoresist is provided on the corrosion resistant film.
The photoresist is exposed so that a pattern corresponding to the outer shape of the crystal piece is formed, development is performed to remove unnecessary photoresist, and patterning is performed to remove the corrosion-resistant film. This patterning is performed, for example, by wet etching using an etchant that does not dissolve the photoresist and the quartz wafer.
A state in which the anti-corrosion film is patterned in this manner and a photoresist is provided on the anti-corrosion film is referred to as a “mask”.
The portion of the pattern formed by removing the corrosion-resistant film is in a state where the surface of the crystal wafer is exposed.

At this time, in the pattern formed by removing the corrosion-resistant film, the side surface facing the Z′-axis is rotated by an angle θ that satisfies −0.5 ° <θ <0 ° with respect to the X-axis. (See FIG. 4).
In this state of patterning, wet etching is performed using an etchant that melts crystal.
Thereby, the several crystal piece 10 can be manufactured from a crystal wafer.

Here, when the angle is 0 °, it means that the mask is manufactured with the mask provided on the crystal wafer as designed.
When the angle θ increases from −0.5 ° to a negative value, a substantially V-shaped streak is generated on the side surface in the longitudinal direction of the crystal piece. This is because when the angle θ is increased from −0.5 ° to a negative value, a large number of crystal planes that are not parallel to the X axis are formed on the long side surface of the crystal piece, and streaks appear on the side surface. Because it will end up.
However, when the angle θ is −0.5 ° <θ <0 °, the substantially V-shaped streak that has conventionally occurred on the side surface in the longitudinal direction of the crystal piece can be eliminated.
This is because, as in the first embodiment, a streak-like pattern does not appear when a crystal plane parallel to the X axis appears on the side surface on the long side.

  Thus, even if it comprises the manufacturing method of the crystal piece which concerns on 2nd embodiment of this invention, there exists the same effect as 1st embodiment.

  10 Crystal fragment

Claims (1)

The X-axis, Y′-axis, and Z′-axis are set by rotating a surface facing the Y-axis side from a crystal having crystal axes of the X-axis, Y-axis, and Z-axis at a predetermined angle around the X-axis. A crystal piece manufacturing method for forming a plate-like crystal piece by performing wet etching after forming a patterned anti-corrosion film and a mask made of a photoresist on the main surface of an AT-cut crystal wafer having a surface facing the surface Because
The orientation of the mask with respect to the X axis about the Y ′ axis,
0 ° <θ <+ 0.5 ° or -0.5 ° <θ <0 °
The quartz crystal is provided on both main surfaces of the quartz wafer parallel to the X-axis and the Z′-axis so as to be in the range, and a plurality of quartz pieces are formed by performing wet etching in this state. Method for forming the piece.

Images