JPH09181546A - Manufacture of crystal resonator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacturing method for a crystal resonator by which the dispersion of the frequency which can be finally obtained can be reduced even when an adjustment vapor deposition is performed in a wafer state and the dispersion of the adjusting amount within the wafer is large. SOLUTION: When a crystal resonator is obtained via a succeeding processing such as an annealing after an electrode 13 for adjustment is formed on the base electrode 6b for every resonator element piece of wafer state crystal substrates in which plural resonator element pieces including the vibration part 4 forming the base electrode 6b on the both surfaces are arrayed longitudinally and latitudinally, the correction value based on the approximate expression by a prescribed function is determined from the relative value of the initial frequency value for every resonator element piece and a target frequency value at the time of forming an electrode 13 for adjustment. Then, the electrode 13 for adjustment of the adjustment vapor deposition amount set by adding this correction value to the relative value is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal oscillator manufacturing method.

[0002]

2. Description of the Related Art A crystal unit is a crystal plate, which is a piezoelectric body, sliced into a predetermined thickness and size, and a base electrode is formed on both sides of the crystal plate as excitation and input / output electrodes. Can be taken out. Since the frequency value at this time depends on the thickness of the crystal plate and the film thickness of the base electrode, in order to compensate for the variations in the thickness of the crystal plate and the film thickness of the base electrode, the frequency around the area where the base electrode is formed is about 1
By forming the frequency adjustment electrode in a region as small as about 100 micrometers, the adjustment vapor deposition step of subtly adjusting the frequency to a desired value has been introduced.

At this time, in order to easily adjust the frequency, a crystal plate having a frequency adjustment amount of about 1000 ppm and having a certain degree of uniformity is selected and mounted on a substrate using solder, a conductive adhesive or the like, and then adjusted. An electrode for forming was formed.

The frequency of the crystal resonator slightly changes after the adjustment deposition, such as annealing.
FIG. 8 shows how the frequency changes before and after the adjustment vapor deposition, which is conventionally performed to correct this. Final target value 21
In order to adjust to, the amount 23 of shift after the adjustment vapor deposition is estimated in advance, and the frequency adjustment vapor deposition is performed by setting the actually adjusted vapor deposition amount 22 to a value shifted from the difference 24 between the initial value 20 and the target value 21. It was

[0005]

However, in the conventional method, since each crystal plate is mounted on a substrate or the like one by one, it takes a lot of time to mount it, and further, the solder used in mounting is used. However, contaminants are generated from the adhesive and the adhesive, which contaminates the surface of the crystal plate during adjustment vapor deposition, resulting in a lack of reliability. Therefore, it is considered effective to arrange a plurality of vibrator elements including a vibrating part having base electrodes formed on both surfaces in a vertical and horizontal direction on a quartz substrate in a wafer state and perform adjusted vapor deposition in a wafer state. In the state of the wafer, the thickness of the vibrating part and the film thickness of the base electrode will inevitably vary within the wafer, so it is not possible to select only the vibrator element with the same frequency. Among them, a large difference will occur depending on the vibrator element. FIG. 9 shows an example of a vibrator element whose initial value 25 is higher than that of FIG. 8. However, such a vibrator element is actually adjusted so as to have the same adjustment frequency 29 as that of the vibrator element of FIG. When the adjusted vapor deposition amount 26 to be performed is set, if a process such as annealing is performed in a post-process after the adjustment, the value becomes 27 which is larger than the shift amount 23 after the adjusted vapor deposition in FIG. Therefore, there is a problem that a vibrator element that cannot obtain the frequency of the target value 21 is generated.

FIG. 10 shows the relationship between the amount of frequency adjustment and the amount of shift of the finished frequency performed on each oscillator element in one wafer. The oscillator element with a large amount of frequency adjustment is shown in FIG. The piece is largely shifted at the time of completion, and the finished frequency has a width of about 10 ppm due to each oscillator element in the wafer, resulting in a large variation in the finished frequency. Further, when a large amount of adjustment exists in the same wafer, this variation width is widened. This is because a large amount of adjustment vapor deposition causes more adjustment electrodes to be formed, so that the amount of change in a subsequent annealing step is large.

According to the present invention, even if the adjustment vapor deposition is performed in a wafer state and the variation in the adjustment amount within the wafer is large,
It is an object of the present invention to provide a method of manufacturing a crystal oscillator in which the amount of shift in each post of each oscillator element is determined in advance and variations in the finally obtained frequency can be reduced.

[0008]

In order to solve the above-mentioned problems, a method of manufacturing a crystal resonator according to the present invention is arranged such that a plurality of vibrator elements including a vibrator having base electrodes formed on both surfaces are arranged vertically and horizontally. When forming the adjustment electrode on the base electrode of each oscillator element of the wafer-shaped crystal substrate, based on the approximation formula by the predetermined function from the relative value of the initial frequency value and the target frequency value of each oscillator element It is characterized in that a correction amount is obtained, and the correction electrode is formed by adding the correction value to the relative value to set the adjusted deposition amount.

According to the present invention, it is possible to obtain a crystal resonator having a small variation in the frequency finally obtained even if the variation in the adjusted deposition amount in the wafer-shaped quartz substrate is large.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a vibrator element of a wafer-shaped crystal substrate in which a plurality of vibrator elements including a vibrating part having base electrodes formed on both sides are arranged in a matrix. After forming the adjustment electrode on each piece of the base electrode, the first and second case bodies are attached to both surfaces through post-processes such as annealing, and then the wafer-like crystal substrate and the first and second Is a method for manufacturing a crystal unit by dividing the case body into the crystal units to obtain a crystal unit, wherein an initial frequency value and a target frequency value for each unit are formed when the adjustment electrode is formed. A quartz oscillator characterized in that a correction value based on an approximate expression based on a predetermined function is obtained from a relative value of and the adjustment electrode is formed by adding the correction value to the relative value to set an adjusted deposition amount. Method for each oscillator element in a wafer-shaped quartz substrate Since the amount of shift that is actually adjusted is corrected by anticipating the amount that will be shifted after adjustment vapor deposition, the amount of variation in the amount of vapor deposition that is adjusted within the quartz crystal substrate in the wafer state is large and the amount that changes in the subsequent process is different for each transducer element. Even if it changes every time, the finally obtained frequency value does not depend on the adjustment vapor deposition amount performed for each vibrator element, and it varies for all vibrator elements in the wafer-shaped crystal substrate. It has an effect of obtaining a small number of crystal oscillators.

The invention according to claim 2 of the present invention is the method of manufacturing a crystal resonator, wherein the approximate expression is any one of a logarithmic function, a higher-order function, an exponential function, or a combination thereof. , When determining the adjustment deposition amount to be performed for each oscillator element on the wafer-shaped crystal substrate, determine the amount to be shifted after the adjustment deposition for each oscillator element in advance, and On the other hand, it has the effect of being able to configure a mechanism for correcting the actually adjusted deposition amount.

According to a third aspect of the present invention, a correction value based on an approximate expression by a predetermined function is obtained from a relative value between an initial frequency value and a target frequency value for each vibrator element of a quartz substrate,
After performing the step of adding the correction value to the relative value and setting the adjusted vapor deposition amount for all the crystal elements of the crystal substrate, adjustment is made for each crystal element of the crystal substrate based on those set values. A method for manufacturing a crystal resonator, which is characterized by forming electrodes for use, in which first, after obtaining a corrected adjusted deposition amount for each crystal resonator element of a wafer-shaped crystal substrate, Since the adjustment electrode is continuously formed on the basis of the corrected adjusted deposition amount, the adjusted deposition process can be efficiently performed.

(Embodiment 1) FIG. 1 shows a crystal resonator used in a first embodiment of the present invention. In FIG. 1, reference numeral 1 is a crystal plate, and a vibrating portion 4 is provided by punching out a groove portion 5 by a method such as sandblasting, and a vibrating portion 4 is provided on both sides of this vibrating portion 4 as electrodes for excitation. Base electrodes 6a and 6b are provided. Reference numerals 2 and 3 denote cases bonded to the crystal plate 1, respectively, and the case 3 is provided with through holes 8 and 9 for taking out electrodes for taking out electrodes to the outside. Extraction electrodes are drawn out from the base electrodes 6a and 6b, and the electrodes drawn out from the base electrode 6b side are drawn out through the through holes 7 to the base electrode 6a side so as to correspond to the through holes 8 provided in the case 3. ing. An adjusting electrode 13 for adjusting the frequency is provided on the side of the base electrode 6b.

Here, the base electrodes 6a and 6b are provided on both surfaces.
A crystal unit having a resonator element including a vibrating section 4 is provided with a first and second case bodies 10 and 12 made of a wafer-shaped crystal substrate 11 shown in FIG. It is configured by dividing the quartz crystal vibrating body. The wafer-shaped crystal substrate 11 is formed by vertically and horizontally arranging a plurality of vibrator elements including a vibrating portion having base electrodes formed on both surfaces.
An adjustment electrode is provided on one of the base electrodes. The first and second case bodies 10, 12 are the quartz substrate 11
A through hole for taking out the electrode to the outside is provided in the vicinity of each of the spot facing portions. The wafer-shaped crystal substrate 11
Is attached to the first and second case bodies 10 and 12 before being combined with each other, an adjusting electrode is provided for the base electrode of each vibrator element to set the target frequency, and thereafter,
A post process such as annealing is performed.

FIG. 10 shows that when the adjustment electrode is adjusted and vapor-deposited so as to have a desired frequency with respect to the base electrode of each vibrator element of the wafer-shaped crystal substrate 11, The relationship between the frequency adjustment deposition amount 22 actually performed and the shift amount of the finished frequency value (the shift amount 23 after the adjustment deposition) is obtained by an experiment. It can be seen that the frequency is more shifted in the case where the adjusted deposition amount is large. From FIG. 10, the correlation between the frequency adjustment vapor deposition amount and the adjusted shift amount can be seen. From this correlation, an approximate expression by a logarithmic function can be obtained as shown in FIG. In FIG. 3, Y
₁ is a logarithmic function, and Y ₁ = a + b · logX ₁ (1) The approximate expression Y ₁₁ is Y ₁₁ = 2.49562−2.3850 · logX ₁₁ (2). At this time, the actual adjustment amount 22 is X ₁₁ ,
Let Y _{11 be} the shift amount of the finished frequency value. Further, at this time, the method of replacing with the expression (1) uses approximate expression replacement by a least square method or the like. Further, when the adjustment vapor deposition is performed, the mask 14 is set so that the adjustment electrode does not protrude above the base electrode 6b as shown in FIG. 5, but the mask area 15 for forming the adjustment electrode causes an experimental value. Since the tendency of changes, it is desirable to perform an experiment each time and obtain an approximate expression.

6 and 7 show the flow of the frequency adjustment process performed in this embodiment. The flow will be described in detail below.

First, as an initial measurement step 30, an initial value 37 of the crystal oscillator before adjustment vapor deposition is measured. Next, as a target relative value calculation step 31, a relative value 39 between the initial value 37 and the finally desired target value 38 is calculated, and as a correction value calculation step 32, the relative value 39 is substituted into X ₁₁ of the equation (2). Then, the value obtained as Y ₁₁ is set as the correction value 40. next,
Correction value 4 obtained in the adjustment vapor deposition amount setting step 33
0 is added to the target relative value 39 (the correction value can be positive or negative, which is added), and this is set as the adjusted vapor deposition amount 41. The above steps are individually performed for each transducer element in the wafer, and the adjusted deposition amount 41 corrected by each transducer element is 41.
Accordingly, in the adjustment vapor deposition step 34, adjustment electrodes are formed on each vibrator element.

With the above-described flow, the adjustment value 42 is determined for each transducer element, so that even if the amount of shift in the post-adjustment step changes for each transducer element, it will eventually A crystal oscillator having a frequency having the target value 38 is obtained for all the oscillator pieces.

At this time, after performing the pre-measurement and adjustment vapor deposition amount setting process for all the pieces of the quartz substrate, the data based on the execution are used for each of the transducer pieces. If the adjustment electrodes are formed continuously, there is no need to make corrections when forming the adjustment electrodes, so there is an advantage that an efficient frequency adjustment step can be performed.

The post-process after the adjustment vapor deposition can be applied to anything that may change the frequency, such as cleaning, other than annealing, etc.

Although the logarithmic function is used in the above embodiment, a linear function as shown in FIG. 4 may be used as another function for the approximation. In this case, Y ₂ is a linear function, and Y ₂ = a + bX ₂ (3) The approximate expression Y ₂₂ is Y ₂₂ = −9.2348-0.0049X ₂₂ (4), which is shown in FIG. 6 and FIG. Relative value 39 indicated by value 39
Is substituted for X ₂₂ in the equation (4), and the value obtained as Y ₂₂ may be used as the correction value 40. Other functions are quadratic functions, 3
A higher-order function such as a quadratic function, an exponential function, and a combination thereof may be used as long as they accurately represent the experimental tendency.

In the above embodiment, the method of performing the adjustment vapor deposition amount setting process on all the wafer-shaped crystal unit pieces and then performing the adjustment vapor deposition is described. After the pre-measurement and setting of the adjusted deposition amount,
An adjustment electrode may be formed.

[0023]

As described above, according to the present invention, when the adjustment vapor deposition is performed on the crystal resonator element in the wafer-shaped crystal substrate, the adjustment amount greatly varies in the wafer and the shift is performed after the adjustment. Even if the amount to be adjusted varies depending on the adjustment deposition amount actually performed, the finally obtained frequency value does not depend on the adjustment deposition amount actually performed, and a desired value is obtained. A crystal oscillator with less variation can be obtained.

[Brief description of the drawings]

FIG. 1 is an assembled perspective view showing a crystal unit to which a first embodiment of the present invention is applied.

FIG. 2 is an assembly perspective view when a plurality of the crystal units are formed on a wafer-shaped crystal substrate.

FIG. 3 is a correlation diagram showing the correlation between the frequency adjustment amount of the crystal unit and the shift amount of the finished frequency value by a logarithmic function approximation.

FIG. 4 is a correlation diagram similarly represented by a linear function approximation.

FIG. 5 is a cross-sectional view in which a mask is set when adjusting and depositing the crystal unit.

FIG. 6 is a flowchart showing a flow of steps for frequency adjustment of the crystal unit.

FIG. 7 is a flowchart showing how the frequency changes in the flow of the frequency adjustment process of the crystal unit.

FIG. 8 is a flow chart showing a state of frequency fluctuation in a process flow of a conventional crystal unit.

FIG. 9 is a flow chart showing how the frequency changes in the process flow of the crystal unit.

FIG. 10 is a correlation diagram obtained from an experiment of the adjusted deposition amount and the shift amount of the finished frequency value with the same crystal unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crystal plate 2 1st case 3 2nd case 4 Vibrating part 5 Groove part 6a Base electrode 6b Base electrode 7 Through hole 8 Electrode extraction through hole 9 Electrode extraction through hole 10 First case body 11 Crystal substrate 12th Second case body 13 Adjustment electrode 14 Mask 15 Mask area 20 Initial value 21 Target value 22 Actually adjusted evaporation amount 23 Shift amount after adjustment 24 Difference between initial value and target value 25 Initial value 26 Actually adjusted evaporation amount 27 Amount to shift after adjustment 28 Difference between initial value and target value 29 Adjustment frequency 30 Initial measurement step 31 Target relative value calculation step 32 Correction value calculation step 33 Adjustment evaporation amount setting step 34 Adjustment evaporation step 35 Post-adjustment process 36 Finished 37 Initial Value 38 Target value 39 Target relative value 40 Correction value 41 Adjustment evaporation amount 42 Adjustment value

Claims (3)

[Claims] 1. An adjustment electrode is formed on a base electrode of each vibrator element of a wafer-shaped crystal substrate in which a plurality of vibrator elements including a vibrating part having base electrodes formed on both surfaces are arranged in a matrix. After the subsequent steps such as annealing, the first and second case bodies are adhered to both surfaces, and then the wafer-like crystal substrate and the first and second case bodies are divided into the oscillator pieces. A method of manufacturing a crystal unit for obtaining a crystal unit, comprising: a correction value based on an approximate expression based on a predetermined function from a relative value between an initial frequency value and a target frequency value for each unit when forming the adjustment electrode. Is obtained, and the correction value is added to the relative value to form an adjustment electrode having an adjusted deposition amount, which is set. 2. The method for manufacturing a crystal unit according to claim 1, wherein the approximate expression is any one of a logarithmic function, a higher-order function, an exponential function, or a combination thereof. 3. A correction value based on an approximate expression by a predetermined function is calculated from a relative value between an initial frequency value and a target frequency value for each crystal element of a quartz substrate, and the correction value is added to the relative value for adjustment. After performing the step of setting the vapor deposition amount for all the vibrator elements of the crystal substrate, the adjustment electrode is formed for each vibrator element of the crystal substrate based on the set values. 1. The method for manufacturing a crystal unit according to 1.