JP4719970B2 - Artificial quartz growth control plate, method for producing artificial quartz using the control plate, and artificial quartz produced by the production method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing an artificial quartz used as a crystal resonator, an optical element, and the like, and an artificial quartz obtained by the manufacturing method, and more particularly to a manufacturing method for selectively growing a growth surface having a specific orientation.
[0002]
[Prior art]
In the artificial crystal growth by the hydrothermal synthesis method, a raw material for growth (raw material crystal) is placed on the lower side and a seed crystal on the upper side, with a convection control plate sandwiched in an artificial crystal growth furnace (autoclave). Further, the growth furnace is filled with a growth solution (alkali solution), and the growth furnace is sealed and heated. Then, a temperature gradient is applied so that the temperature lower than the upper side of the growth furnace is higher, and the growth solution is convected in the growth furnace. Thereby, the raw material for growth melt | dissolved in the lower part in a growth furnace reaches the upper part in a growth furnace, and at that time, it will be cooled and will be in a supersaturated state and will precipitate and grow on a seed crystal. By performing this operation continuously for a predetermined period, an artificial quartz crystal having a predetermined size can be obtained.
[0003]
In recent years, the use of artificial quartz as an optical component in addition to quartz resonators or as a surface acoustic wave element is increasing. When used as an optical component, it is required to reduce impurities in the crystal as much as possible, and when used as a surface acoustic wave device, it is required to provide a specific growth region with a large wafer from the viewpoint of manufacturing efficiency. It was. In order to meet such a demand, a manufacturing method in which a specific orientation is mainly grown as disclosed in Japanese Patent Publication No. 57-49520 was invented. Japanese Examined Patent Publication No. 57-49520 is a manufacturing method in which the upper basic growth surface of the seed crystal is cut off by a plate (control plate) made of a material different from the crystal, thereby generating crystals on the lower basic growth surface. Among them, an L-shaped control plate having a vertical side wall that suppresses growth in the + X-axis direction with respect to the control plate main body is disclosed, thereby controlling the growth in two directions and ensuring a wide practical area. It is shown.
[0004]
However, when such an L-shaped control plate with a right angle of bending is used, the crystal grows up to the corner of the L-shape, and when the artificial crystal growth is completed, the L-shaped control plate and the grown artificial crystal firmly adhere to each other. There was a case. In such a case, it is difficult to separate the crystal, and the work may cause a crack in the artificial quartz, and the usable area that can be used as a crystal resonator element is reduced, resulting in a decrease in manufacturing yield.
[0005]
[Problems to be solved by the invention]
The present invention has been made to solve the above-described problems, has a large practical area, is easy to separate the grown artificial crystal from the control plate, and has a good quality with little damage to the artificial quartz. It is an object of the present invention to provide a control plate for crystal growth, a method for manufacturing an artificial crystal using the control plate, and an artificial crystal by the manufacturing method.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present inventor conducted a study of a control plate that does not firmly adhere to a crystal to be grown with respect to a control plate that regulates the growth of artificial quartz in a plurality of directions. The present invention has been found to solve the above problems by adjusting the angle formed between the control plate body and the side wall to an acute angle, and by forming a protrusion or a ridge protruding inward on the side wall. It is characterized by.
[0007]
That is, as shown in claim 1, when manufacturing an artificial quartz crystal by hydrothermal synthesis using thermal convection, the control plate is brought into close contact with the main surface of the seed crystal and suppresses growth in a specific direction, The control plate has a side wall that suppresses growth of at least one side surface of the seed crystal, and an angle formed by the control plate main body and the side wall is 70 to 88 degrees .
[0008]
According to the first aspect, the seed crystal mainly grows in the direction opposite to the direction in which the control plate is arranged. For example, the main growth surface of the Z plate crystal (XY plane) is the thickness direction (Z-axis direction), but when only one Z growth surface side is grown, the control plate is brought into close contact with the other Z growth surface, By proceeding with the growth in this state, a crystal grows mainly on one Z growth surface side.
[0009]
Moreover, although the side wall which suppresses the growth of the side surface of a seed crystal is provided, since the angle of the corner | angular part of a control board main body and a side wall is an acute angle, the alkaline solution supplied to the said corner | angular part is restrict | limited. For this reason, as shown in FIG. 4, the growth region 6a indicated by hatching reaches the side wall first, and this makes it difficult to supply a new alkaline solution to the corners. Therefore, it is considered that the growth of the artificial quartz in the corner portion is extremely slowed down. 4 is a view of the control plate as viewed from the + X-axis direction (side wall), 6 is a seed crystal, 61 is a grown artificial crystal, 7 is a control plate, and 71 is a side wall.
[0010]
The angle needs to be less than 90 degrees. However, if the angle is too small, the supply of the alkaline solution is drastically reduced from the beginning, so that the growth of the practical area is hindered. FIG. 5 is a diagram schematically showing the angle of the corner and the growth of artificial quartz. In each figure, 6 is a seed crystal, 61 is a grown artificial crystal, 7 is a control plate, and 71 is a side wall. FIG. 5A shows a case where the side wall is erected at 90 degrees with respect to the main surface of the control plate main body. In this case, although depending on the state of thermal convection, in many cases, the artificial crystal grows up to the corner C. FIG. 5B shows a state in which the angle of the side wall is tilted to 82 degrees. The tip of the side wall is not configured to cover the end of the seed crystal 6. In this case, the artificial quartz crystal does not grow up to the area of the corner C regardless of the number of days for cultivation. FIG. 5 (c) shows a state in which the side wall angle is about 65 degrees and the inside wall is tilted considerably. The tip of the side wall covers the end of the seed crystal 6, that is, when the perpendicular is drawn from the tip of the side wall to the control plate main body, it intersects the seed crystal. In this case, the artificial quartz crystal does not grow up to the region of the corner C regardless of the number of growing days, but the tip portion of the side wall inhibits the growth of the seed crystal in the Z direction, that is, the growth of the practical region.
[0011]
Although the angle also depends on the side wall dimensions, it was experimentally possible to perform good artificial quartz crystal growth in the range of 70 to 88 degrees. When the perpendicular is drawn from the front end portion of the side wall to the control plate main body, the angle may be an angle that does not cover the end portion of the seed crystal 6. The angle is preferably 72 degrees to 85 degrees in consideration of the artificial crystal growing environment and variations in the installation state (tilt and the like) of the control plate in the autoclave.
[0012]
Further, as shown in claim 2, in manufacturing an artificial crystal by a hydrothermal synthesis method using thermal convection, an artificial crystal growing control board that suppresses growth in a specific direction in close contact with the main surface of the seed crystal. The control plate has a side wall that suppresses growth of at least one side surface of the seed crystal, and an angle formed between the control plate main body and the side wall is 70 to 88 degrees, and protrudes inward from the side wall. The structure in which the protrusion or protrusion which performs is formed may be sufficient.
[0013]
According to claim 2, it is possible to obtain the same effect as when the above-mentioned angle is set to an acute angle. That is, since the protrusion or protrusion protruding inward is formed on the side wall, the alkaline solution supplied to the corner portion is particularly limited by the protrusion or protrusion. For this reason, it is considered that the growth region reaches the protrusion or the ridge portion first, and thereby the growth of the artificial quartz in the corner portion is extremely slowed down. Therefore, the growth of artificial quartz does not proceed to the corners.
[0014]
As shown in claim 3, the control plate according to claim 1 or 2 may be made of metal.
[0015]
According to the third aspect, since the control plate is made of metal, plastic processing such as bending or providing protrusions and protrusions is easy, and the control plate main body and the side wall can be adjusted in angle or at any position on the side wall. Work such as providing protrusions can be freely performed.
[0016]
Furthermore, as shown in claim 4, in claim 1 or claim 2, the control plate may be made of a metal plate having a quartz film formed on the surface thereof.
[0017]
According to claim 4, in addition to the above effects, the crystal growth generated on the surface of the metal plate and the grown artificial quartz are not firmly fixed, and the Z growth in which the control plate after the completion of the growth is arranged The surface is almost flat as a seed crystal. Therefore, peeling from the control plate is very easy, and the artificial quartz grown during the peeling operation is not damaged. In addition, since the flat state of the seed crystal is maintained, an extremely smooth surface with a fixed cutting orientation can be obtained, and therefore it can be used as a reference surface in various subsequent cutting processes.
[0018]
A fifth aspect of the present invention relates to a method for manufacturing an artificial quartz crystal using each of the control plates, wherein the control plate according to any one of the first to fourth aspects is provided on the upper surface of the seed crystal having a predetermined cutting orientation, and thermal convection is used. Discloses a method for producing an artificial quartz crystal using a hydrothermal synthesis method.
[0019]
According to the fifth aspect of the present invention, crystal growth at the corner is suppressed by making the angle between the control plate main body and the side wall an acute angle. In the growth furnace, the growth solution is convectively heated, but impurities are also convected together with the growth solution. According to the above configuration, since the control plate is arranged above the seed crystal to be grown (in many cases, upstream of the thermal convection), it prevents the deposition of impurities in the seed crystal and the artificial crystal in which crystal growth has progressed. To do. Therefore, an artificial quartz with few impurities can be obtained. In addition, since the grown crystal has a structure in which the seed crystal is located on the end face, by excising the seed crystal part at the end, an artificial crystal of good and uniform quality that does not hinder the optical characteristics of the crystal is obtained. Obtainable.
[0020]
Further, when the control plate according to the fourth aspect is used, peeling from the control plate is very easy, and the artificial quartz grown during the peeling operation is not damaged. In addition, since the flat state of the seed crystal is maintained, it is possible to obtain a very smooth surface with a fixed cutting orientation.
A sixth aspect of the present invention relates to a method for manufacturing an artificial quartz crystal in the case where a specific configuration of the seed crystal is shown. The seed crystal is an XY plane crystal plate, and the crystal is mainly grown in one Z-axis direction, and the + X axis By using the control plate according to any one of claims 1 to 4 in which a side wall is formed on the side, growth in the + X-axis direction is suppressed.
[0022]
The main growth surface of the XY plane crystal (Z plate crystal) is the thickness direction (Z-axis direction), but when only one Z growth surface side is grown, the control plate is brought into close contact with the other Z growth surface, By proceeding with the growth in this state, a crystal grows mainly on one Z growth surface side. According to the sixth aspect, in addition to the effect of the fifth aspect, it is possible to obtain an artificial quartz crystal extending in the Z-axis direction with good and uniform quality.
[0023]
The artificial quartz produced by the production method according to claim 5 or claim 6 is extremely easy to peel off from the control plate, does not cause damage to the artificial quartz grown by the peeling work, and has a cutting orientation. An extremely smooth surface can be obtained. Further, the content of impurities can be extremely reduced.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0025]
-Explanation of the structure of the artificial crystal growth furnace-
First, the configuration of an artificial crystal growth furnace (hereinafter simply referred to as a growth furnace) for growing an artificial crystal using the artificial crystal growth solution (hereinafter simply referred to as a growth solution) according to the present invention will be described. To do.
[0026]
FIG. 1 is a cross-sectional view showing the internal configuration of the growth furnace 1 according to the present embodiment. As shown in FIG. 1, in the growth furnace 1, an electric furnace (not shown) is disposed around the outer periphery of the furnace body 2, and the furnace body 2 is heated by the electric furnace 3. The furnace body 2 has a bottomed cylindrical shape with an open top, and a lid 22 for sealing the internal space 4 of the furnace body 2 is attached to the upper end opening 21. A pressure gauge for measuring the internal pressure of the furnace body 2 is attached to the lid body 22. Furthermore, a convection control plate 23 is disposed at an intermediate position in the vertical direction of the internal space 4 of the furnace body 2. By this convection control plate 23, the internal space 4 of the furnace body 2 is partitioned into a lower raw material chamber 41 and an upper growth chamber 42.
[0027]
The raw material chamber 41 contains a natural crystal (Lasca) 5 as a raw material for growth. On the other hand, a plurality of seed crystals 6, 6,... Supported by the crystal growth shelf F are accommodated in the growth chamber.
[0028]
Further, the interior space 4 of the furnace body 2 is filled with a growth solution (alkali solution) which is a feature of this embodiment.
[0029]
-Explanation of artificial crystal growth operation-
The artificial crystal growing operation by the growth furnace 1 containing the natural crystal 5 and the seed crystal 6 as described above and filled with the growing solution will be described below.
[0030]
In this growing operation, the furnace body 2 is heated by the electric furnace 3. This heating state is set so that the raw material chamber 41 is hotter than the growing chamber 42, and due to this temperature difference, the culturing solution is heated between the raw material chamber 41 and the growing chamber 42 under high temperature and pressure. Let In this embodiment, for example, the temperature of the growth chamber 42 is set to 320 ° C., and the temperature of the raw material chamber 41 is set to 360 ° C. That is, heat convection is performed by setting the temperature difference between the two chambers 41 and 42 to 40 ° C. The temperature and temperature difference between the two chambers 41 and 42 are not limited to this.
[0031]
As a result, the natural crystal 5 dissolved in the raw material chamber 41 reaches the growing chamber 42, and at that time, it is cooled and becomes supersaturated and precipitates and grows on the seed crystal 6. By performing this operation continuously for a predetermined period, an artificial quartz crystal having a predetermined size can be obtained.
[0032]
FIG. 2 is an exploded perspective view showing a configuration for attaching a seed crystal. In the figure, crystal axis directions (X, Y, Z) of quartz are shown, and the subsequent drawings are also shown in the same manner. 3 is a cross-sectional view in the lateral direction in the assembled state in FIG. 2, and FIG. 4 is a side view in the longitudinal direction.
[0033]
The seed crystal 6 is a rectangular Z-plate crystal, and is supported in large numbers so as to be positioned at right angles to the vertical direction of the growth furnace. More specifically, a large number of support tools F1, F1 are arranged at a predetermined interval on the crystal growing shelf F, and the seed crystal 6 is supported in an erected state between the support tools F1, F1. . Each support is formed with positioning steps F2, F2, and a control plate 7 is placed in close contact with the seed crystal on the upper surface side of the seed crystal. The control plate 7 uses an iron plate (metal plate) with a crystal coating 7b formed on the surface, and has a side wall 71 that regulates growth in the X-axis direction.
[0034]
As a method for generating a quartz film on an iron plate, for example, it is formed by hydrothermal synthesis for a short time in a growth furnace as shown in FIG. In other words, the raw material chamber of the growth furnace accommodates Lasca, and the iron plate constituting the base material 7a of the control plate is suspended at a predetermined interval in the growth chamber, and is placed in an environment similar to crystal growth for several days. As a result, a thin crystallized crystal is deposited on the surface of the iron plate, and the control plate 7 having a crystal film (crystallized film) 7b formed on the surface can be obtained. Such a method can of course be applied to a metal plate having a plurality of side walls as shown in FIG.
[0035]
The angle between the control plate main body 70 and the side wall 71 is set to an acute angle of about 82 degrees. After the seed crystal is installed on the supports F1 and F1, the upper surface of the seed crystal is covered with a control plate, and the control plate is fixed to the supports F1 and F1 with a locking tool (not shown).
[0036]
As crystal growth proceeds, the seed crystal grows mainly in the Z-axis direction without the control plate and also in the X-axis direction as indicated by the dotted line in FIGS. At this time, the side wall 71 is formed on the + X axis side, and the side wall 71 is inclined inward at an acute angle, so the alkaline solution supplied to the corner C is limited. For this reason, as shown in FIG. 4, the region 6 a indicated by hatching reaches the side wall 71 first, and the growth of the artificial quartz does not proceed to the corner C. This facilitates the work of removing the artificial quartz after completion of the growth and the control plate in the subsequent process, and can minimize damage to the artificial quartz.
[0037]
Another structure of the support will be described with reference to the drawings. 6 is an exploded perspective view, FIG. 7 is a longitudinal sectional view when FIG. 6 is assembled, and FIG. 8 is a sectional view in the short direction. In this configuration, the configuration of the control plate is different from the above embodiment. That is, the control plate 8 uses an iron plate (metal plate) and has side walls 81 and 82 for regulating growth in the X-axis direction. The angle between the control plate body and the side wall is both 88 degrees. Since this is a configuration in which side walls are formed in both the X-axis directions, the supply of the alkaline solution to the seed crystal portion is slightly reduced. Therefore, by setting an open structure as compared with the case of the above embodiment, the supply of the alkaline solution is promoted to aim at efficient crystal growth.
[0038]
As shown in FIG. 6, a large number of a pair of supporting tools F1, F1 are arranged at a predetermined interval on the crystal growing shelf F, and the seed crystal 6 is installed between the supporting tools F1, F1. It is supported. A control plate 8 is installed in close contact with the seed crystal on the upper surface side of the seed crystal. The control plate 8 is fixed to the supports F1 and F1 by a locking tool or the like.
[0039]
According to such a configuration, it is possible to obtain an artificial quartz crystal in which the growth of one of the Z planes, the −X plane, and the + X plane is regulated, and each regulated growth plane can be in a flat state. it can.
[0040]
Next, a configuration in which protrusions are formed on the side walls of the control plate will be described with reference to the drawings. 9 is a cross-sectional view in the short direction of the control plate showing a state in which the artificial quartz is grown. In this configuration, the configuration of the control plate is different from the above embodiment. That is, the control plate 9 uses an iron plate (metal plate) and has a side wall 91 that regulates growth in the X-axis direction. A projection 91a is formed on the side wall so as to protrude toward the seed crystal installation side. It is preferable to form a plurality of projections, and the growth shape of the artificial quartz crystal can be controlled by predicting the state in which the grown artificial quartz contacts the side wall and forming the projections in necessary portions. It is also possible to control the growth shape of the artificial quartz with higher accuracy by changing the size of the protrusions.
[0041]
FIG. 10 shows an example in which a plurality of protrusions are formed on the control plate 9 having the side wall 91. In addition, FIG. 10 is the figure which looked at the side surface toward the -X direction from + X side, and 6 has shown the seed crystal. The protrusions protrude in the −X direction and change in size, and the protrusions 91c and 91d and the sizes thereof are set larger toward the end from the protrusion 91b in the central portion. Thereby, the growth shape of the artificial quartz is controlled.
[0042]
FIG. 11 shows an example in which a strip 91 e extending in a strip shape is formed on the control plate 9 having the side wall 91. In addition, FIG. 11 is also the figure which looked at the side surface toward the -X direction from + X side, and 6 has shown the seed crystal. The growth shape of the artificial quartz is controlled by the protrusion.
[0043]
In addition, it is possible to control the supply of an alkaline solution (growing solution) efficiently by combining protrusions and protrusions, or by adopting the above-described adjustment of the side wall angle and the combination of protrusions or protrusions.
[0044]
【The invention's effect】
According to the first aspect, since the angle between the corners of the control plate main body and the side wall is an acute angle, the crystal growth in specific plural directions is suppressed, and the artificial quartz is prevented from growing to the corners. be able to. Therefore, the artificial crystal growth control plate having a large practical area, easy separation of the grown artificial crystal and the control plate, and less damage to the artificial crystal, and a method for manufacturing the artificial crystal using the control plate and An artificial quartz crystal produced by the manufacturing method can be obtained.
[0045]
According to the second aspect of the present invention, since the protrusions or ridges projecting inward are formed on the side wall, the crystal growth in a specific plurality of directions is suppressed, and the artificial quartz does not grow to the corners. Can be. Therefore, the artificial crystal growth control plate having a large practical area, easy separation of the grown artificial crystal and the control plate, and less damage to the artificial crystal, and a method for manufacturing the artificial crystal using the control plate and An artificial quartz crystal produced by the manufacturing method can be obtained.
[0046]
Further, according to the third aspect, since the control plate is made of metal, the bending process is easy, and the angle adjustment between the control plate main body and the side wall can be freely performed.
[0047]
According to claim 4, in addition to the above effects, the crystal growth generated on the surface of the metal plate and the grown artificial quartz are not firmly fixed, and the Z growth in which the control plate after the completion of the growth is arranged The surface is almost flat as a seed crystal. Therefore, peeling from the control plate is very easy, and the artificial quartz grown during the peeling operation is not damaged. In addition, since the flat state of the seed crystal is maintained, an extremely smooth surface with a fixed cutting orientation can be obtained, and therefore it can be used as a reference surface in various subsequent cutting processes.
[0048]
According to the fifth aspect of the present invention, crystal growth at the corner is suppressed by making the angle between the control plate main body and the side wall an acute angle. In the growth furnace, the growth solution is convectively heated, but impurities are also convected together with the growth solution. According to the above configuration, since the control plate is arranged above the seed crystal to be grown (in many cases, upstream of the thermal convection), it prevents the deposition of impurities in the seed crystal and the artificial crystal in which crystal growth has progressed. To do. Therefore, an artificial quartz with few impurities can be obtained.
[0049]
According to the sixth aspect, in addition to the function and effect of the fifth aspect, the grown crystal is an artificial crystal grown in the Z-axis direction where the seed crystal is located on the end face, and thus does not hinder the optical characteristics of the crystal. Suitable for optical components.
[Brief description of the drawings]
1 is a cross-sectional view showing an internal configuration of a growth furnace; FIG. 2 is an exploded perspective view showing a support; FIG. 3 is a longitudinal cross-sectional view in a state where growth is performed according to FIG. Fig. 5 is a cross-sectional view in a short direction in a state of being performed. Fig. 5 is a diagram schematically showing the angle of a corner and the growth of artificial quartz. Fig. 6 is an exploded perspective view showing another configuration example of a support. FIG. 8 is a cross-sectional view in the longitudinal direction in the state grown according to FIG. 6. FIG. 8 is a cross-sectional view in the short direction in the state grown from FIG. FIG. 11 is a side view showing another configuration example of the plate. FIG. 11 is a side view showing another configuration example of the control plate.
DESCRIPTION OF SYMBOLS 1 Artificial crystal growth furnace 2 Furnace main body 4 Internal space 5 Natural crystal 6 Seed crystal 7, 8, 9 Control board 71, 81, 82, 91 Side wall 91a, 91b, 91c, 91d Projection 91e Projection F1 Support tool

Claims (6)

In producing an artificial quartz crystal by hydrothermal synthesis using thermal convection, a control board that suppresses growth in a specific direction in close contact with the main surface of the seed crystal,
The control plate has a side wall that suppresses growth of at least one side surface of the seed crystal, and an angle formed by the control plate main body and the side wall is 70 degrees to 88 degrees. . In producing an artificial quartz crystal by hydrothermal synthesis using thermal convection, a control board that suppresses growth in a specific direction in close contact with the main surface of the seed crystal,
The control plate has a side wall that suppresses the growth of at least one side surface of the seed crystal, and an angle formed between the control plate main body and the side wall is 70 degrees to 88 degrees. A control board for artificial quartz crystal growth characterized in that a protrusion is formed.   3. The artificial quartz crystal growth control plate according to claim 1, wherein the control plate is made of metal.   3. The artificial quartz crystal growth control plate according to claim 1, wherein the control plate is made of a metal plate having a quartz film formed on a surface thereof.   A method for producing an artificial crystal by hydrothermal synthesis using thermal convection, wherein the control plate according to claim 1, claim 2, claim 3, or claim 4 is provided on an upper surface of a seed crystal having a predetermined cutting orientation.   The seed crystal is an XY flat crystal plate, and the growth in the + X-axis direction is suppressed by growing the crystal mainly in one Z-axis direction and using a control plate with a side wall on the + X-axis side. The method for producing an artificial quartz crystal according to claim 5.

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