JPH11346136A - Manufacture of quartz oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a quartz oscillator which can stably produce an element which is superior in temperature characteristics and in productivity. SOLUTION: Metal films 21 and 22 for forming axial inversion part are formed on both sides of an electrode 2 on a surface of a quartz substrate 1 and, axial inversion parts 11 and 12 having an electric axis in the opposite direction to the electric axis of an excitation part 4 are formed in the quartz substrate 1, by executing heat treatment with a procedure such as laser beam irradiation, so that the parts out of the quartz substrate 1 which form the metal films 21 and 22 is heated to a temperatures higher than a α.βtransition temperature of quartz and parts, which do not form the metal films 21 and 22 have the temperatures lower than the α.β transition temperature of the quartz.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitably used for a clock generator of a computer, a local oscillator or a filter of a wireless communication device, and can obtain a stable resonance frequency and a filter frequency even when the ambient temperature fluctuates. The present invention relates to a method for manufacturing a crystal resonator.

[0002]

2. Description of the Related Art Conventionally, as a vibrator used in a resonance circuit of an oscillator for generating an electric signal of a constant frequency, there is a crystal vibrator capable of obtaining a stable resonance frequency with respect to a temperature change. FIG. 10 is a perspective view showing a conventional crystal unit. In the figure, reference numeral 1 denotes an AT-cut crystal substrate having an electric axis (X) and a temperature coefficient of frequency of 0, and reference numerals 2 and 3 denote crystal substrates. An excitation electrode 4 made of Al, Au, or the like formed on both surfaces of 1 is an excitation section which is a box-shaped area sandwiched between the electrodes 2 and 3. This crystal oscillator is configured to apply a high frequency voltage near the resonance frequency between the electrodes 2 and 3 to
It is possible to generate electric vibration of a specific frequency in the range of about kHz to 100 MHz.

The above-described resonance frequency of the crystal unit has a characteristic represented by a cubic curve when the ambient temperature is used as a parameter. Therefore, when the temperature fluctuation is small, the fluctuation of the resonance frequency does not matter. However, when used in an environment where the temperature fluctuates greatly, the fluctuation of the resonance frequency becomes large and cannot be ignored. Therefore, by combining with a temperature-sensing element that can obtain a temperature compensation voltage that cancels out this characteristic, for example, a temperature compensation circuit using a thermistor whose temperature characteristic is represented by an exponential function, the resonance frequency can be reduced to the ambient temperature. Is provided with a temperature-compensated crystal oscillator (TCXO) that is changed substantially linearly.

[0004] In general, if twins are present in a crystal for an electronic device, the characteristics of the device will be adversely affected. Also, it is considered that there is no twin crystal in the quartz substrate used as the oscillator in the quartz oscillator and the quartz oscillator.

[0005]

However, in the above-described crystal oscillator (TCXO), several electronic components are required in addition to the thermistor to constitute the temperature compensation circuit, and the number of electronic components used is small. There are various drawbacks, such as an increase in price and an increase in the adjustment of the circuit of the crystal oscillator. On the other hand, the resonance frequency-temperature characteristic of the quartz substrate represented by the cubic curve is considered to be a characteristic unique to the quartz substrate, and it has been considered that there is no room for improvement in the quartz substrate itself.

Therefore, the inventors of the present invention provided an electric shaft of the excitation unit 4 near the excitation unit 4 of the conventional crystal unit shown in FIG. 10 in order to provide the crystal unit with a temperature compensation function. We have proposed a crystal resonator with an axis reversal part having an electric axis in the opposite direction. In this crystal resonator, a part of the vibration energy generated in the excitation part is leaked to the axis reversal part by forming the axis reversal part having the electric axis in the direction opposite to the electric axis of the excitation part near the excitation part. To compensate the temperature of the crystal unit. For example, in the case of an AT-cut quartz substrate, at room temperature, the resonance frequency of the excitation unit has a negative temperature characteristic, whereas the resonance frequency of the axis inversion unit has a positive temperature characteristic. By leaking the tail portion of the distribution to the axis inversion portion, the positive temperature coefficient and the negative temperature coefficient are canceled out, and the temperature characteristics of the excitation unit are compensated by the action of the axis inversion portion. As a result, even when the ambient temperature fluctuates, a stable resonance frequency can be obtained without using a temperature compensation circuit or the like. In other words, this crystal resonator effectively utilizes the characteristics of the twin structure, which has been said to have an adverse effect.

In manufacturing this crystal resonator, when a crystal substrate having a metal thin film of Cr, NiCr, etc. formed on its surface is subjected to heat treatment, a stress generated by the metal thin film acts on a region immediately below the metal thin film in the crystal substrate. The electric axis of is reversed. Therefore, by using a metal thin film, a temperature lower than the α · β transition temperature (Tc = 573 ° C.) of quartz, for example, 540 to 55
The advantage is obtained that the axis can be inverted even at a temperature of about 0 ° C. By such a method, it is possible to form an axis reversal part having an electric axis in a direction opposite to the electric axis of the excitation part at a position different from the excitation part in the quartz substrate, and a twin crystal comprising the excitation part and the axis reversal part in the quartz substrate A structure can be formed.

However, when a quartz oscillator was actually manufactured by using the above-described method, an element having poor temperature characteristics was produced during the manufacture of a plurality of elements, and an element having excellent temperature characteristics became stable. Therefore, there is a problem that the yield is reduced. In particular, when the element is to be miniaturized, it is difficult to control the position where the axis reversal part is formed with respect to the excitation part, and there is a concern that the yield may be further reduced.

The present invention has been made in view of the above circumstances, and provides a method of manufacturing a crystal resonator which can stably manufacture an element having excellent temperature characteristics and can cope with miniaturization of the element. The purpose is to do.

[0010]

In order to achieve the above-mentioned object, a method of manufacturing a crystal resonator according to the present invention comprises forming a film for forming an axis reversal portion on one side, both sides, or the periphery of an electrode portion on the surface of a crystal substrate. Formed, and then, of the quartz substrate, the portion where the axis reversal portion forming film is formed has a temperature equal to or higher than the α / β transition temperature of quartz, and the portion where the axis reversal portion forming film is not formed is By heat-treating the substrate to a temperature lower than the α-β transition temperature of the crystal, an axis reversal portion having an electric axis in a direction opposite to the electric axis of the excitation portion is formed in the crystal substrate. It is. In the method for manufacturing a crystal resonator according to the present invention, a film for forming an axis reversal portion is formed in the vicinity of an electrode portion on the surface of a crystal substrate, and the portion where the film for forming an axis reversal portion is formed has an α · β transition temperature of quartz. Above temperature,
The substrate is heat-treated with a temperature difference so that the other parts have a temperature equal to or lower than the α-β transition temperature of the crystal, so that axis inversion occurs only in the area where the axis inversion portion forming film is formed,
A crystal oscillator having excellent temperature characteristics can be stably manufactured. In addition, according to this manufacturing method, it is difficult to receive the effect of the substrate manufacturing history and the edge effect of the substrate on miniaturization, and a high yield can be expected.

As the specific method of the heat treatment, there are two methods, that is, a method using infrared irradiation and a method using laser beam irradiation. In the case of using the infrared irradiation method, infrared rays are irradiated on the entire surface of the substrate. However, due to the difference in heat capacity between the crystal and the film for forming the axis reversal portion, the portion between the portion where the film for forming the axis reversal portion is formed and the portion where the film is not formed is formed. Causes a temperature difference. At this time, it is desirable that the temperature difference be 400 ° C. or less. This is because the portion where the axis reversal portion forming film is formed has a temperature equal to or higher than the α / β transition temperature of the crystal, the other portion has a temperature equal to or lower than the α / β transition temperature of the crystal, and the temperature difference is 400 ° C.
C. or more means that the temperature of the portion where the film for forming the axis reversal portion is formed becomes considerably higher than the α-β transition temperature of the crystal. %, Which leads to a decrease in yield. The inversion ratio is the ratio of the area of the portion where the axis inversion actually occurs to the area where the axis inversion portion forming film is formed (the area where the axis inversion portion is to be formed). When the reversal occurs, it becomes 100%.
When the axis reversal portion is formed so as to extend beyond the film formation region, the value is 100% or more. When the axis reversal portion for the film formation region is not formed, the value is 100% or less.

The material of the film for forming the axis reversal portion may be Cr, Ni, NiCr, Ti, Ta, Mo, W, C
Any of u, Al, Au, and Ag or an oxide thereof can be used. The film thickness may be 1 μm or less. Since these noble metals and oxides are chemically stable to quartz, they do not need to be peeled off even after they are used during heat treatment. Absent. Therefore, the step of removing the film can be omitted. In addition, the metal serving as the axis reversal portion forming film has a stable heat capacity necessary for axis reversal,
In addition, from the viewpoint of the deposition time when forming the film, the value of the film thickness that is not too thick is preferably 1 μm or less. When Cr was used, it was actually confirmed in the range of 500 ° to 1 μm.

On the other hand, when the laser beam irradiation method is used, only the portion where the axis reversal portion forming film is formed can be extremely locally heated by using the laser beam irradiation device. Therefore, in the laser beam irradiation method, for example, 1
It is possible to relatively easily form a pattern of a minute axis reversal portion having a size of not more than 00 μm or an axis reversal portion having a special shape, which is a method particularly suitable for development use.

Since local heating is possible in the laser beam irradiation method, if the laser beam is irradiated to the portion where the film for forming the axis reversal portion is formed, the temperature difference between the portion and the other portion is inevitably increased. Will be attached. The temperature difference is desirably 550 ° C. or less. This is because if the temperature difference is increased to 550 ° C. or more, cracks in the substrate occur due to thermal strain, and the yield decreases. The temperature of the portion where the axis reversal portion forming film is not formed may be room temperature.

Regarding the material of the film for forming the axis reversal portion, as in the case of the infrared irradiation method, Cr, Ni, NiCr, Ti,
Any metal of Ta, Mo, W, Cu, Al, Au, and Ag or an oxide thereof can be used. In the laser beam irradiation method capable of locally heating, the film thickness of the axis reversal portion forming film is 4000 ° or less. In the case of the laser beam irradiation method, the metal used as the film for forming the axis reversal portion has a stable heat capacity necessary for axis reversal, and the film thickness is not so thick from the viewpoint of the deposition time during film formation. 4000Å
The following is preferred.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a perspective view showing a crystal resonator according to an embodiment of the present invention. As shown in FIG. 1A, excitation electrodes 2 and 3 made of a metal such as Cr are provided on both surfaces of an AT-cut quartz substrate 1 having an electric axis (X).
Are formed. Reference numeral 4 denotes an excitation section which is a box-shaped area sandwiched between these electrodes. On both sides of the excitation unit 4 in the quartz substrate 1, axis reversing units 11, 12 having an electric axis (-X) in the opposite direction to the electric axis (X) of the excitation unit 4 are formed. Cr, Ni,
Metal thin films 21 and 22 made of NiCr or the like are formed.

In this crystal resonator, when a high-frequency voltage near the resonance frequency is applied between the electrodes 2 and 3, an amplitude distribution f of vibration displacement as shown in FIG. 1B is obtained. That is,
Due to the energy confinement effect based on the mass addition effect of the electrodes 2 and 3, most of the vibration energy concentrates on the excitation unit 4, but a part leaks to reach the axis reversing units 11 and 12, and as a result, the temperature characteristics are reduced. Be improved.

Hereinafter, a first manufacturing method of the crystal resonator having the above configuration will be described. This method is a method of performing heat treatment by infrared irradiation. First, the size is 10mm x 12m
2A, an AT-cut quartz substrate having a thickness of 0.08 mm is prepared, and as shown in FIG. 2A, the electron beam (E) is placed on the surface of the quartz substrate 1 at a position where the axis reversing portions 11 and 12 are to be formed.
B) Metal thin film 2 made of a transition metal such as Cr or Ni, or an alloy thereof such as NiCr by a vapor deposition method or the like.
1 and 22 (film for forming an axis reversal portion) are formed. At this time, the thickness of the metal thin films 21 and 22 is 3000 °.

Next, the quartz substrate 1 on which the metal thin films 21 and 22 are formed is heat-treated using an infrared irradiation device. FIG. 3 is a diagram showing a schematic configuration of the infrared irradiation device. Closed container 3
An infrared lamp 32 is provided on the upper part of the lamp 1, and the output of the infrared lamp 32 can be adjusted by a lamp controller 33. A susceptor 34 made of quartz glass is provided below the infrared lamp 32 in the closed container 31 and holds the quartz substrate 1 to be heated thereon. Further, a thermocouple 35 is provided in the susceptor 34.
Is built-in so that the heating temperature can be monitored.

In the infrared irradiation device, metal thin films 21, 2
The crystal substrate 1 on which the metal thin films 21 and 22 are formed is placed in an atmosphere of 1% H ₂ / N ₂ , and
Heat-treating the substrate so that the temperature is equal to or higher than the β transition temperature T _c (573 ° C.) and the temperature of the other portions is equal to or lower than T _c ;

Here, in order to grasp the temperature difference between the portion where the metal thin film is formed and the portion where the metal thin film is not formed, a quartz substrate on which a Cr film is formed and a quartz substrate on which no metal thin film is formed are prepared. These substrates were individually heat-treated by using the infrared irradiation apparatus shown in FIG. 3 to measure the temperature. FIG. 4 shows the results. In FIG. 4, the horizontal axis is the infrared irradiation time (minutes), and the left vertical axis is the thermocouple temperature (° C.) in the susceptor (in this case, the temperature was measured not by the measured temperature of the substrate but by the temperature of the susceptor in contact with the substrate). The vertical axis on the right side is the lamp output (%).

As shown in this figure, the lamp output is 1 kW
The output of the lamp is changed stepwise by the controller, and during 0 to 5 minutes, 30% of the maximum output, 5 to 10 minutes
The output was set to 50% of the maximum output during minutes, and 60% of the maximum output during 10 minutes to 30 minutes. Looking at the temperature transition on the quartz substrate on which the Cr film is formed (the curve connecting the circles) and the temperature transition on the quartz substrate without the Cr film formed thereon (the curve connecting the triangles), between 0 and 5 minutes ( (Output: 30%), there is almost no difference in temperature, but after 5 minutes, a difference starts to appear, and after 30 minutes, the temperature of the quartz substrate on which the Cr film is formed is about 25 ° C. higher. Therefore, it was confirmed that a temperature difference certainly occurred between the quartz substrate on which the metal thin film was formed and the quartz substrate on which the metal thin film was not formed by infrared irradiation.

Next, the relationship between the lamp output and the substrate temperature immediately below the metal thin film was investigated. Using the quartz substrate having the Cr film formed thereon, using a 1 kW lamp, 30% of the maximum output for 0 to 5 minutes, and 50% of the maximum output for 5 to 10 minutes.
%, 100% of the maximum output during 10 to 15 minutes, and the lamp output was changed stepwise, and the output was turned off in 15 minutes. Then, the temperature of the substrate immediately below the Cr film was measured immediately before the output was turned off. FIG. 5 shows the result of performing temperature measurement while changing the maximum output of the lamp. The horizontal axis in FIG. 5 is the maximum output (%) of the lamp, and the vertical axis is the measured temperature (° C.) of the quartz substrate immediately below the Cr film.
Is shown.

As shown in FIG.
When it was changed from 6% to 65%, the measured temperature of the crystal increased with the increase in the maximum output of the lamp, and the α · of the crystal increased to about 575 ° C at 60% of the maximum lamp output and about 595 ° C at 61%. It was found to exceed the β transition temperature T _c (573 ° C.). Also, from the results of FIG. 4, the temperature of the portion where the Cr film is formed is about 25 ° C. higher than the temperature of the portion where the Cr film is not formed.
If it is controlled within the range of ~ 61%, the portion where the Cr film is formed is higher than the α / β transition temperature _{Tc of the} quartz crystal (about 575 ° C to 595 ° C), and the other portions are at the temperature lower than _Tc (550 ° C).
(About 570 ° C. to about 570 ° C.).

By performing the infrared irradiation while controlling the lamp output in this manner, the portion where the metal thin films 21 and 22 are formed becomes higher than the α / β transition temperature T _{c of the} crystal, and the other portions are lower than T _c . Heat treatment is performed so as to reach a temperature. At this time, an electric axis at a position where the axis reversing portions 11 and 12 are to be formed in the quartz substrate 1 is reversed by a stress caused by the metal thin films 21 and 22. Thereby, as shown in FIG.
Inverted portions 11 and 12 having an electric axis (−X) opposite to the electric axis (X) of the excitation section 4 are formed inside the quartz substrate 1.

Here, an experiment was conducted to verify whether or not the axis reversal portion was normally formed by the method of manufacturing a crystal resonator according to the present embodiment. As a sample, as shown in FIG.
A Cr substrate 21 having Cr patterns 21 and 22 formed at two locations on the surface of an AT-cut quartz substrate 1 having a size of 3.0 mm × 4.8 mm was manufactured. The size of the Cr patterns 21 and 22 is 0.4 mm × 2.2 mm, and the interval between the patterns is 1.44.
mm. This sample was heat-treated with the above-mentioned infrared irradiation device at various lamp outputs, and the formation state of the axis reversal portion was investigated.

FIG. 7 is a diagram showing the lamp output dependence of the reversal rate. The horizontal axis in the figure is the lamp output (%), and the vertical axis is the reversal rate (%) with respect to the Cr film formation area. As shown in FIG. 7, when the lamp output is in the range of 60% to 61%, the reversal rate is stable at almost 100%. However, the lamp output is 6
As soon as it exceeds 1%, the reversal rate greatly varies in the range of 100% to 350%. This is because, when the lamp output exceeds 61%, as shown in FIG.
Although the temperature is higher than the α-β transition temperature T _c of the crystal in the region where the film is formed, the temperature is too high as a whole, and is higher than the α-β transition temperature T _{c of the} crystal even in the region where the Cr film is not formed. It is because. That is, under these experimental conditions, if the lamp output during infrared irradiation is controlled in the range of 60% to 61%, the axis reversal portion can be formed with good controllability only in the region of the quartz substrate on which the Cr film is formed. all right.

After the heat treatment, as shown in FIG. 2C, electrodes 2 and 3 are formed on both surfaces of the quartz substrate 1 by an electron beam (EB) evaporation method or the like. By the above steps, FIG.
A crystal resonator having the amplitude distribution f of the vibration displacement shown in (b) can be obtained.

As described above, in the method of manufacturing the crystal resonator according to the present embodiment, the metal thin films 21 and 22 are formed in the vicinity of the excitation section 4 of the crystal substrate 1 and the portions where the metal thin films 21 and 22 are formed are formed. Heat-treats the substrate so that the temperature is equal to or higher than the α-β transition temperature of the crystal and the portion where the metal thin films 21 and 22 are not formed is equal to or lower than the α-β transition temperature of the crystal. Only the portion where is formed is surely axis-reversed, and a crystal resonator having excellent temperature characteristics can be stably manufactured. According to this manufacturing method,
A high yield can be expected because the heat treatment conditions are set so that the substrate is hardly affected by the manufacturing history of the substrate and the edge effect of the substrate on miniaturization, and the reversal rate is almost 100%.

Hereinafter, a second method for manufacturing the crystal resonator having the above-described configuration will be described. This method is a method of performing heat treatment by laser beam irradiation. First, a quartz substrate similar to that of the above-described first manufacturing method is prepared, and as shown in FIG. 8A, EB vapor deposition or the like is provided on the surface of the quartz substrate 1 at a position where the axis reversing portions 11 and 12 are to be formed. Thus, metal thin films 21 and 22 having a thickness of 3000 ° made of a material such as Cr, Ni, and NiCr are formed.

Next, the quartz substrate 1 on which the metal thin films 21 and 22 are formed is heat-treated using a laser beam irradiation device. FIG.
Is the laser beam irradiation device actually used (Toshiba Seiki Co., Ltd.)
FIG. 1 is a diagram showing a schematic configuration of a YAG laser processing apparatus (LAY-803A type) manufactured by YAMAHA. A stage 42 is provided on a base 41, and the quartz substrate 1 is held on the stage 42 so that laser light is emitted. The laser light is emitted from a laser light source unit 44 set above the power supply unit 43, and irradiates the quartz substrate 1 via a lens unit 45. A stage controller 46 for controlling the operation of the stage 42 is provided.

In this laser beam irradiation device, a metal thin film 21 is provided.
8B, the laser light was applied to the metal thin film under the conditions of a set voltage: 190 V, a pulse width: 10 ms, a repetition rate: 8 pps, and a spot irradiation time: 15 sec, as shown in FIG. Irradiation is performed on the portions 21 and 22 so that the portion where the metal thin films 21 and 22 are formed has a temperature equal to or higher than the α / β transition temperature of the crystal, and the portion where the metal thin films 21 and 22 are not formed is equal to or lower than the α / β transition temperature of the crystal. The heat treatment is performed so as to reach the temperature.

The subsequent steps are the same as those in the first manufacturing method. As shown in FIG.
The electrodes 2 and 3 are formed by a vapor deposition method or the like, and a quartz oscillator can be obtained.

In the case of this method using laser light irradiation for the heat treatment, the same effect as that of the first method can be obtained in that a quartz oscillator having excellent temperature characteristics can be manufactured with a high yield. In addition, in the case of the present method, unlike the first method in which the entire substrate is irradiated with infrared rays, only the portions where the metal thin films 21 and 22 are formed can be extremely locally heated by laser light.
m, the pattern of the axis reversal part as fine as less than m or the axis reversal part having a special shape can be formed relatively easily. After being assembled into the package, the laser beam is irradiated from the glass window of the package top lid. This method is particularly suitable for development applications.

The technical scope of the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention. For example, the shapes and dimensions of the excitation unit and the axis reversing unit can be determined as appropriate. Also, various conditions for infrared irradiation and laser beam irradiation can be arbitrarily selected.

[0036]

As described above in detail, according to the method for manufacturing a crystal resonator of the present invention, a film for forming an axis reversal portion is formed near the electrode portion on the surface of the quartz substrate, and the axis reversal portion is formed. The axis-reversed portion is formed because the substrate is heat-treated so that the portion where the film is formed has a temperature equal to or higher than the α-β transition temperature of the crystal and the other portions have a temperature equal to or lower than the α-β transition temperature of the crystal. Only the portion where the film is formed is surely axis-reversed, and a crystal resonator having excellent temperature characteristics can be stably manufactured. In addition, according to this manufacturing method, it is difficult to receive the effect of the substrate manufacturing history and the edge effect of the substrate on miniaturization, and a high yield can be expected. Further, when heat treatment is performed by laser light irradiation, a fine axis inversion portion or a pattern of an axis inversion portion having a special shape can be formed relatively easily, which is a method particularly suitable for development use.

[Brief description of the drawings]

FIGS. 1A and 1B are views showing a crystal resonator according to an embodiment of the present invention, wherein FIG. 1A is a perspective view and FIG. 1B is a cross-sectional view taken along line II of FIG.

FIG. 2 is a process diagram showing a first method of manufacturing the crystal unit according to the embodiment.

FIG. 3 is a diagram showing a schematic configuration of an infrared irradiation device used at the time of heat treatment in a first manufacturing method.

FIG. 4 is a graph showing the relationship between infrared irradiation time and temperature for a quartz substrate on which a Cr film is formed and a quartz substrate on which a Cr film is not formed.

FIG. 5 is a graph showing the relationship between lamp output and temperature for a quartz substrate on which a Cr film is formed.

FIG. 6 is a diagram showing a sample in which the formation state of the axis reversal part is verified.

FIG. 7 is a diagram showing the lamp output dependence of the reversal rate of the sample.

FIG. 8 is a process chart showing a second method of manufacturing the crystal unit of the embodiment.

FIG. 9 is a view showing a schematic configuration of a laser beam irradiation apparatus used at the time of heat treatment in a second manufacturing method.

FIG. 10 is a perspective view showing a conventional crystal unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Quartz crystal substrate 2, 3 Electrode 4 Exciting part 11, 12 Axis reversal part 21, 22 Metal thin film (film for axis reversal part formation) f Amplitude distribution of vibration displacement in length direction X Electric axis -X Electric axis in opposite direction

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Eiji Kamiyama 1-297 Kitabukurocho, Omiya City, Saitama Prefecture Mitsubishi Materials Research Institute (72) Inventor Terumo Ito 1-297 Kitabukurocho, Omiya City, Saitama Mitsubishi Materials Research Institute

Claims (10)

[Claims] 1. A method of manufacturing a crystal unit, wherein excitation electrodes are formed on both surfaces of a crystal substrate, and a region sandwiched between the electrodes is used as an excitation unit. Forming a film for forming the axis reversal part on one or both sides or around, then, of the quartz substrate, the part where the film for forming the axis reversal part is formed has a temperature equal to or higher than the α-β transition temperature of the crystal, By performing heat treatment so that the portion where the axis reversal portion forming film is not formed has a temperature equal to or lower than the α / β transition temperature of the crystal, the electric axis in the direction opposite to the electric axis of the excitation unit in the crystal substrate. A method for manufacturing a crystal resonator, comprising: forming an axis reversal portion having: 2. The method according to claim 1, wherein the heat treatment is performed by irradiating infrared rays to the quartz substrate on which the axis reversing portion forming film is formed. 3. The method according to claim 1, wherein a temperature difference between a portion of the crystal substrate on which the axis reversal portion forming film is formed and a portion of the crystal substrate on which the axis reversal portion forming film is not formed is 400 ° C. or less. The method for manufacturing a quartz oscillator according to claim 2, wherein: 4. The film for forming an axis reversal part, wherein the film for forming the axis reversal part is
NiCr, Ti, Ta, Mo, W, Cu, Al, Au,
4. The method for manufacturing a quartz resonator according to claim 2, comprising a metal of Ag or an oxide thereof. 5. The method according to claim 4, wherein the thickness of the axis-reversing portion forming film is 1 μm or less. 6. The method according to claim 1, wherein the heat treatment is performed by irradiating the axis reversal portion forming film with a laser beam. 7. A temperature difference between a portion of the quartz substrate on which the axis reversal portion forming film is formed and a portion of the crystal substrate on which the axis reversal portion forming film is not formed during the heat treatment is 550 ° C. or less. A method for manufacturing a crystal resonator according to claim 6, wherein: 8. The method according to claim 7, wherein a temperature of a portion of the quartz substrate on which the axis reversal portion forming film is not formed is set to room temperature during the heat treatment. 9. The film for forming an axis reversal part, wherein the film is Cr, Ni,
NiCr, Ti, Ta, Mo, W, Cu, Al, Au,
9. The method of manufacturing a quartz resonator according to claim 6, wherein said method is made of any metal of Ag or an oxide thereof. 10. The film thickness of the axis reversal portion forming film is 400.
The method according to claim 9, wherein the angle is 0 ° or less.