JPH0141050B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a mounting method for a glass-sealed crystal resonator that can withstand glass-sealing temperatures. An object of the present invention is to provide a method for manufacturing a crystal resonator of higher quality. Another object of the present invention is to provide an inexpensive method of manufacturing a crystal resonator. An example of a conventional method for manufacturing a crystal resonator will be explained with reference to FIG. 1 is a stem, and two lead wires 2 and 6 made of Kovar or the like are positioned and set in a metal ring 3 made of Kovar or the like.
Sealed with glass 4 whose coefficient of thermal expansion is equal to or close to metal such as Kovar (hermetic seal)
It is what was done. The crystal oscillation piece 5 has an outer shape formed by photolithography or machining, and has electrodes formed by vapor deposition, sputtering, etc. on its surface (not shown).
The crystal oscillator piece 5 and the inner lead wires 2', 6' can be joined by brazing with a relatively low melting point material such as solder, gold-tin (Au-Sn) eutectic, silver paste, adhesive, etc. This is done by adhesion. The joint serves both to hold the oscillating piece and to provide external continuity. After bonding, a thin film for frequency adjustment is formed on the tips 7, 7' of the crystal oscillator pieces, and the mass of the thin film is removed by laser trimming, or gold or silver is applied to the tips 7, 7' of the crystal oscillator pieces. Frequency adjustment is accomplished by adding mass by depositing metal, such as by adding mass. Next, in order to improve the vibration characteristics, the case 8, the stem 1, and the crystal oscillation piece 5 are each heated in a vacuum to sufficiently remove gas components adhering to the surfaces. The case 8 thus degassed is press-fitted into the metal ring 3 of the stem described above in a vacuum to maintain the vacuum and protect the vibrator. This is called encapsulation. The case 8 is generally formed by plating nickel silver with a soft metal such as solder, and this soft metal is used as a sealing material for vacuum maintenance. Further, since it is press-fitted, the relationship between the case inner diameter and the stem outer diameter is that the case inner diameter is small and has an interference. Here, the drawbacks of the above conventional method are shown below. (1) Parts unit price is high. The stem and case were extremely expensive and accounted for a large proportion of the unit cost of the crystal unit. This is because the stem uses Kovar for the metal outer ring and lead wire, which results in high material costs.Also, when manufacturing the stem, the metal ring must be molded with high precision because it is press-fitted into the case later.
Furthermore, a process of press-molding the glass powder, positioning the three parts, melting the glass and sealing it, and plating the metal surface of the metal ring and lead wire with Ni etc. to improve the contact resistance. However, the processing cost was very high. On the other hand, the case also has a two-step process in which metal such as nickel silver is pressure-formed and then metal such as solder is plated on the surface of the case to facilitate press-fitting.
Processing costs were extremely high. (2) There are the following quality issues. Poor aging characteristics. In the conventional method, in the degassing process by heating in a vacuum, the case is plated with soft metal such as solder, so it cannot be heated above the melting point, and the solder plating is porous and absorbs a large amount of gas. Because of this, degassing is insufficient, and residual gas is generated from the case surface after being sealed, resulting in a change in the oscillation frequency of the vibrator, which has the drawback of poor aging characteristics. There is a vacuum leak during sealing. In the conventional manufacturing method of crystal resonators, the case is plated with soft metal such as solder and then press-fitted into the metal ring of the stem. This has the disadvantage that sometimes the case and stem are not brought into sufficient contact with each other, and the degree of vacuum within the crystal resonator cannot be maintained. Expansion of frequency distribution during encapsulation. In the conventional manufacturing method of a crystal resonator, since a metal case is used, the only way to adjust the frequency of the crystal resonator is to adjust the frequency of the crystal resonator before encapsulating the crystal resonator. However, according to the conventional manufacturing method, by press-fitting the case into the stem at the time of encapsulation, the minute vibrations occurring in the stem are suppressed, resulting in the frequency after encapsulation being different from the frequency immediately after frequency adjustment. . Furthermore, as the amount of change differs depending on the individual product in mass production, the frequencies of the same lot at the time of completion have spread widely. Therefore, when it is necessary to select and manufacture a certain narrow frequency range, this becomes a factor that greatly reduces the yield. Therefore, in order to eliminate the above-mentioned drawbacks, the present applicant has previously invented and filed a patent application for a crystal resonator using a glass stem and a glass case, and a method for manufacturing the same, so this is presented as a prior example. The number of such a prior example is JP-A-57-115012. However, this manufacturing method also has problems that will be described later. The present invention has been made to solve this problem. In order to facilitate understanding of the advantages of the present invention, a crystal resonator and its manufacturing method, which are a precedent example of the present application, will be described here. The prior art method overcomes the above-mentioned drawbacks of such conventional methods and provides a crystal resonator of excellent quality at low cost. A method of manufacturing a crystal resonator according to a prior art example will be explained below with reference to FIGS. 2a and 2b. A shows a state diagram in which a dumet wire is attached to glass, and b shows a state diagram in which a crystal vibrating piece is attached to it. 9 is a glass stem, and 2 such as a dumet wire
The lead wires 10 and 12 of the book are sealed with a glass 11 having a coefficient of thermal expansion equal to or close to that of the metal of the dumet wire. (The main difference from the conventionally used stem is that there is no metal ring.) Reference numeral 5 denotes a crystal oscillation piece, which may be manufactured by a conventional method, that is, a photolithography method or a machining method. The base of the crystal oscillation piece 5 and the inner lead wires 12, 12' are bonded using a bonding material having heat resistance of 200° C. or more. The joining of the prior art example described above is configured to satisfy the following conditions. That is, the bonded parts must withstand the temperature during glass sealing described below. Therefore, the melting point within the mount material is
The temperature must be 200℃ or higher. Conventional sealing methods require a mounting material with a melting point that is approximately 150°C lower than the glass softening point.

[Table] *Based on Nippon Electric Glass glass characteristics table.
For example, LG-16 (Nippon Electric Glass KK) in Table 1
When using glass for the case and stem, the softening temperature must be 425°C or higher, which is 150°C lower than the glass's softening point of 575°C. However, it has been found that it is possible to lower the melting point of the mount material to 200°C by applying local heating during sealing, or by sealing while cooling the lead wire from below. As the joining method, the following implementation method can be mentioned. (1) Brazing Gold-tin alloy, gold-silicon alloy, silver brazing,
Melting point of aluminum wax, magnesium wax, etc.
Brazing with brazing metal at 200℃ or higher. (2) Crimp inner lead wires 12, 12' of glass stem 9
Gold plating (silver plating is also acceptable) is applied to the lead wire, and the lead wire is placed on top of the metal thin film of the crystal oscillator piece, and pressure bonded by diffusion bonding while heating. Furthermore, even if the lead wires are not plated, crimping is possible if the copper on the surface of the lead wires is not oxidized. (3) Welding lead wire 1 of glass stem to crystal oscillator piece 5
2, 12', and irradiate the lead wires 12, 12' with a laser.
are heated and melted to join. Alternatively, set the lead wires 12, 12' of the glass stem on the crystal oscillator piece 5, and while applying pressure, instantaneously apply a large current between the lead wires 12, 12' and the metal thin film of the crystal oscillator piece 5, heating and melting the contact portion. and join. (4) Caulking Form the tip of the lead wire into a “U” or “U” shape that can hold the base of the crystal resonator.
Caulk. After the crystal oscillation piece is bonded to the lead wire by any of the bonding methods described above, the glass stem is degassed in vacuum at a temperature below its heat resistant temperature. On the other hand, the glass case is also degassed by heating it to 500°C in a vacuum. Thereafter, the glass case 13 is attached to the glass stem 9, and the contact portion between the glass stem 9 and the glass case 13 is heated in a vacuum to seal them. The inner diameter of this glass case 13 is made slightly larger than the outer diameter of the glass stem 9. The above-mentioned sealing method differs depending on the mounting material, but in general, as shown in Fig. 3, the stem 9 with the crystal oscillator piece 5 mounted on the graphite jig 14 and the glass case 13 are set, and the graph is placed in a vacuum. 600~ by energizing the eye jig
The glass is melted by heating to 850° C., and the glass stem 9 and the glass case 13 are sealed. Another method of sealing is to irradiate the contact area between the glass stem 9 and the glass case 13 with a carbon dioxide laser that can heat the glass to melt and seal the glasses of the glass stem 9 and the glass case 13. . The sealing temperature is set to be higher than the lower of the softening points of the glass stem and the glass case.
If at least one of them is softened, mutual diffusion will proceed rapidly and sealing will be easily achieved. If the sealing temperature is too high, the glass stem and glass case may be deformed or the crystal oscillator piece may be transformed, which is not preferable. After sealing, in order to remove thermal distortion remaining in the glass stem and glass case, it is desirable to keep the entire structure at a temperature below the lowest of the melting point of the mounting material, the softening point of the glass, and the transformation point of the crystal. This increases the strength of the finished crystal resonator. Frequency adjustment can be done by either a weighting method before sealing or a weighting method after sealing. Here, we will show the conditions required for the glass stem and glass case used in the previous example. The first condition is that the softening point must be 850°C or lower.
There are two reasons for this. The first reason is to prevent the temperature from rising above 573° C., which is the transformation point of the crystal oscillator piece, when the glass is sealed. Quartz has a transformation point at 573°C, and if it is heated above this temperature it will generate twins, which will remain even if the temperature is lowered. This gives a decisive factor of deterioration to the frequency temperature characteristics and Q value. Therefore, it is necessary to avoid heating the crystal oscillator piece above 573°C. The second reason is to avoid problems such as peeling off by applying excess heat to the mount. Therefore, setting the softening point to 850°C or lower means that the crystal oscillator piece will heat up to 573°C when the glass is sealed.
It can be seen that this is the limit temperature that does not rise above the transformation point of . During glass sealing, there is a temperature difference of approximately 150°C or more between the crystal tuning fork body and the glass sealing temperature, so the permissible softening point of the glass is 850°C or less. However, when implementing the preceding example, it is desirable to use a material with a softening point as low as possible. In addition, the second condition required for the glass is that the lead wires must be made of the same material with the same coefficient of thermal expansion, or the difference in coefficient of thermal expansion must be ±, in order to alleviate thermal distortion during sealing.
It must be within 10×10 ^-7 /℃, preferably ±5×10 ^-7 /℃ or less. Table 1 shows examples of glass materials that satisfy these conditions. The method for manufacturing a crystal resonator according to the prior example has the following advantages, which will be explained in comparison with the conventional example. (1) It will be cheaper. The stem and case that make up a conventional crystal resonator are very expensive, and the component unit cost of the crystal resonator is large. This is because the stem uses Kovar for the metal outer ring and lead wire, which results in high material costs, and when manufacturing the stem, the metal ring must be molded with high precision because it is later press-fitted into the case. Furthermore, there is a process of press-molding the glass powder, positioning the three parts, sealing the glass, and plating the metal surface of the metal ring and lead wire with Ni to improve the contact resistance. Therefore, processing costs were extremely high. On the other hand, the case also requires two steps: pressure-forming a metal such as nickel silver, and then plating the surface of the case with a metal such as solder to facilitate press-fitting, resulting in extremely high processing costs. The glass stem and glass case used in the previous example have a simple structure in which two dumet wires are fixed with glass, so the dumet wire itself is cheaper than Kovar, and furthermore, it does not use a metal ring. Since there is no need for plating or plating, the material cost is extremely low, and since there are fewer steps in the processing process, the processing cost is significantly lower. On the other hand, in the case of a glass case, the material cost is low because only a glass tube is formed, and the processing cost is also low because solder plating and the like are not necessary. Therefore, the price of the glass stem and glass case of the prior application is approximately 4:1 compared to the price of the conventional stem and case. (2) Quality improves. According to previous examples, the following quality improvements can be made. Improved aging characteristics In conventional manufacturing methods, during the degassing process by heating in vacuum, the case cannot be heated above its melting point because it is plated with soft metal such as solder, and the solder plating is porous and extremely difficult to heat. Because a large amount of gas is adsorbed in the vacuum case, degassing becomes insufficient, and residual gas is generated from the case surface after filling, the degree of vacuum inside the vacuum case changes, and the oscillation frequency of the resonator changes, that is, aging characteristics. has deteriorated. In the manufacturing method according to the previous example, since the case is made of glass, it is possible to release gas at a higher temperature in a vacuum, and since glass itself inherently generates less gas, the degree of vacuum changes due to residual gas after sealing. is reduced, and the aging characteristics are greatly improved. Furthermore, the glass stem to which the crystal oscillation piece is bonded uses a bonding method that can withstand higher temperatures than conventional ones, so the temperature during degassing can be raised, resulting in a better degassing effect and even better aging characteristics. improves. Vacuum leakage during sealing is reduced. In the conventional manufacturing method of crystal resonators, the case is plated with soft metal such as solder and then press-fitted into the metal ring of the stem. The problem was that the stem and stem were not in sufficient contact with each other, and the degree of vacuum within the crystal resonator could not be maintained. However, according to the prior art, the stem and the glass case are completely fused together by heat fusion, so no vacuum leakage occurs, and the yield and reliability during encapsulation are greatly improved. Reducing the frequency distribution when completed In the conventional manufacturing method, a metal case was used, so the only way to adjust the frequency of the crystal oscillator was to adjust the frequency before encapsulating it. However, according to the conventional manufacturing method, the minute vibrations occurring in the stem are suppressed by press-fitting the case into the stem at the time of enclosing, so that the frequency after enclosing is different from the frequency immediately after frequency adjustment. Furthermore, as the amount of change differs depending on the individual product in mass production, the frequencies of the same lot at the time of completion have spread over a wide range. Therefore, when it is necessary to select and manufacture a certain narrow frequency range, this becomes a factor that greatly reduces the yield. In the previous method of manufacturing a crystal resonator, the case is transparent because it is made of glass.
After encapsulation, the electrode film at the tip of the crystal tuning fork can be trimmed to adjust the frequency using a laser beam such as a YAG laser that passes through glass. Therefore, the frequency can be adjusted after the frequency has changed due to encapsulation, and adjustment can be performed in a very narrow frequency range with good yield. In addition, this allows the frequency adjustment to be performed just before shipping to absorb aging shifts in inventory, or the frequency adjustment to be performed after being assembled into the watch body to absorb frequency shifts due to assembly, and the trimmer codenser Accurate adjustment can be made without the need for frequency adjustment parts such as As described above, the crystal resonator and its manufacturing method according to the previous example are far superior to the conventional method, but in order to obtain a high-quality glass-sealed resonator at an even lower price, the following problems must be addressed. have. In order to fuse the glass stem and the glass case, it is necessary to heat the glass to a temperature above the softening point of either glass, which with current technology is over 350°C. In the prior patent, it is stated that the temperature of the mount part can be lowered to 200℃ by local heating or by sealing the lead wire while cooling it, but due to the characteristics of glass. There is a drawback that when local heating or cooling occurs, microcracks occur, reducing airtightness and strength. Therefore, in effect, heating the sealed part to 350°C will result in a glass case.
Glass stems and lead wires are heated to over 300℃, so conventional solder (melting point around 180℃), gold-tin amorphous alloy (melting point 280℃), silver paste, etc. cannot be used as mounting materials. .
As a countermeasure to this problem, it is possible to mount with a brazing material with a melting point of 300°C or higher, or to mount by thermocompression bonding. However, in the former case, there is no brazing material that can be formed using an inexpensive plating method, so it is possible to mount by supplying a brazing material from outside. Moreover, the latter has the disadvantage that sufficient mounting strength cannot be obtained because the mounting area cannot be large. The present invention provides a mounting method that can improve the above-mentioned drawbacks and fully bring out the advantages of the glass-sealed crystal resonator described above. More specifically, the metal coating formed on the mounting portion of the crystal oscillator and the metal coating formed on the lead wire are overlapped, and the latter metal is melted and mounted. Since quartz has an irreversible transformation point at 573℃,
It cannot be heated above this temperature. On the other hand, the mount part has at least 300
℃ heat is added. That is, the mounting conditions are as follows. (1) Mount temperature is below 573℃. (2) The heat resistance of the mount part during sealing is 300℃ or higher. The only single metals that meet this condition are cadmium and thallium. In addition, there are many eutectic alloys with safe melting points that meet the above conditions, including silver-antimony, but most of them are difficult to obtain as an alloy plating film and are difficult to obtain when mounting the crystal oscillator and lead wires. The above-mentioned eutectic alloy filler metal must be supplied from In the present invention, a low melting point metal is formed on the lead wire by plating or the like, and a high melting point metal (573
300°C or higher) are melted and stacked on top of each other, and the former low melting point metal is melted and diffused with the latter metal.
It is characterized by forming and mounting an alloy or intermetallic compound having a melting point higher than ℃. Next, the mounting method according to the present invention will be explained in detail. 1. A metal coating with a thickness of 1 to 10 μm and a melting point of 573° C. or higher is formed on the mount portion of the crystal oscillator. At this time,
As shown in FIG. 5, the weight 15 for F tuning by laser and the mounting metal 16 can be formed at the same time. This metal coating is made of gold, silver, copper, nickel, etc., and is formed by electroplating or electroless plating. 2 The inner lead wire 2 of the glass stem has a thickness of 1~
Forms a metal film with a diameter of 30μ and a melting point of 573℃ or less.
This metal coating includes tin, cadmium, indium, zinc, lead, and their alloys.
Formed by electroplating or electroless plating. Note that the metal coating may be formed on the outer lead wire at the same time as the inner lead wire to soften the crystal resonator to a circuit or the like. 3. Layer the metal coatings formed in 1 and 2 above and heat to a temperature above the melting point of the metal coating 2 and below 573°C. As a result, the metal coating of the lead wire melts and spreads over the metal coating of the crystal oscillator, forming an alloy or intermetallic compound having a melting point higher than the melting point of the former metal coating. The melting point at this time is
Both metals are selected so that the temperature will exceed 300℃. Examples of metal combinations are shown in Table 2. Needless to say, the invention is not limited to the examples in Table 2.

[Table] In particular, even if the metal formed on the lead wire is an alloy such as solder, it may exhibit an effect equal to or better than that of a single metal. Next, the reason for limiting the melting point and thickness of each metal coating will be described below. The metal coating formed on the crystal oscillator must have a melting point higher than the crystal transformation temperature of 573°C for operational reasons. If the thickness is less than 1 μm, mounting strength cannot be obtained, and if it is more than 10 μm, there will be too much mounting material and the characteristics of the crystal oscillator will also be significantly degraded. The metal coating formed on the lead wire must be below the crystal transformation temperature of 573°C in order to be mounted. If the thickness is less than 1 μm, sufficient mounting strength cannot be obtained, and if it is more than 30 μm, there will be too much mounting material and the characteristics of the crystal oscillator will be significantly degraded, and the number of man-hours required for plating will be too high, making it impractical. The melting point of the alloy or intermetallic compound formed in the mount must withstand the temperature during glass sealing, so the melting point of the current practical low melting point glass and the external solderability of the crystal resonator requires a temperature of 300°C or higher. Limited. After mounting in this manner, the glass stem and glass case are covered with a glass case as shown in Figure 3, and the joint between the glass stem and glass case is heated and melted in a vacuum to seal the glass stem and glass case as shown in Figure 4. Although it is desirable that the materials used be the same, even if they are different, the difference in thermal expansion coefficient must be within ±5×10 ⁻⁷ /°C. The glass used is low melting point glass whose main component is lead oxide. In addition to lead oxide, lead fluoride,
Glasses with various thermal expansion coefficients and softening points are made by blending boric acid, zinc oxide, silicon dioxide, aluminum oxide, tellurium oxide, thallium oxide, sodium oxide, potassium oxide, vanadium oxide, zinc fluoride, antimony oxide, etc. can be manufactured. Therefore, a glass with a thermal expansion coefficient equal to that of the lead wire and a softening point of 350 to 650°C is selected from the viewpoint of strength and workability. When sealing the glass stem and glass case, the mount part is heated to near the sealing temperature, so the heat-resistant temperature of the mount material must be at least 300℃, even considering the temperature difference between the sealing part and the mount part. It is. In the present invention, for example, if the crystal oscillator is made of silver and the lead wire is made of tin, the melting point of tin is 232°C.
If mounted at a slightly higher temperature, a high melting point (approximately 480°C) alloy of silver and tin will be formed between the crystal oscillator and the lead wire by thermal diffusion, and the glass will be fixed with the heat-resistant mounting material. can withstand temperatures of That is, the present invention has provided a mounting method that operates at as low a temperature as possible during mounting and withstands this temperature during sealing. After mounting and sealing, the frequency is adjusted by trimming the weight formed at the tip of the crystal oscillator using a YAG laser. The weight can be made of the same metal material at the same time as the metal coating is formed on the mount portion of the crystal oscillator. Of course, the object of the present invention is not departed from the object of the present invention even if the metal coating of the mount portion and the weight for laser trimming are formed separately. Next, examples of the present invention will be described below. Example 1 The mount part and frequency adjustment part of the crystal oscillator were plated with gold to a thickness of 3μ by electrolytic plating. On the other hand, the lead wire made of the aluminum wire was plated with 10 μm of zinc. Glass case and glass stem are lead glass L-29F (manufactured by Nippon Electric Glass, equivalent products from other companies also available)
Manufactured by. The outer diameter of the case is 2mmφ, the inner diameter is 1.6
mmφ and height 6mm, the lead wire of the glass stem was 0.2mmφ, and the outer diameter of the stem was 1.5mmφ. The inner lead wire of the glass stem was set over the mount of the crystal oscillator, and the mount was passed through a belt furnace in an inert gas atmosphere at 430°C to complete the mounting. Next, as shown in Figure 1, set the glass stem and glass case in the heating jig 7, and heat the joint of the glass case and glass stem to 630°C for 10 minutes while maintaining a vacuum of 1 x 10 ^-5 or more. and sealed it. At this time, the mount was heated to approximately 550°C, but the mount did not melt and the crystal oscillator was held by the lead wire. Next, the frequency was adjusted by trimming the weight at the tip of the crystal oscillator using a YAG laser that passes through the glass. When we checked the quality of the crystal resonator manufactured in this way, we found that it had characteristics equal to or better than those of conventional metal-sealed crystal resonators. In particular, the high-temperature storage characteristics at 80℃ x 240 hours have a frequency shift of approximately ±
An extremely excellent result of ±0.3ppm, less than half of 0.7ppm, was obtained. This is because the temperature during glass sealing is higher than the conventional baking temperature of 100-odd degrees.
This is thought to be because a sufficient baking effect was obtained and there were fewer substances that easily adsorbed gas. Example 2 As in Example 1, the lead wires of the crystal oscillator and glass stem were plated with 5μ of silver and 10μ of tin, respectively. The glass material of the stem and case is lead oxide 77.5
%, zinc oxide 10%, boric acid 10%, silicon dioxide
2.5% and a softening point of 366°C was used. After mounting in an inert atmosphere furnace at 300°C, the glass stem and glass case were sealed at 430°C. As for the characteristics as a crystal resonator, almost the same results as in Example 1 were obtained. Example 3 Using the same glass case and glass stem as in Example 1, the crystal oscillator was plated with 5μ silver and the lead wire was plated with 8μ cadmium.
Mounted at 350°C and sealed at 630°C. The characteristics as a crystal resonator were almost the same as in Example 1. Next, the effects of the present invention will be explained by analyzing Example 1. The zinc coating formed on the lead wire is melted by heating during mounting and flows onto the gold coating formed on the crystal oscillator. When heated for a suitable period of time, zinc and gold will diffuse into each other, forming an alloy with a higher melting point than zinc between the crystal oscillator and the lead wire. When this was analyzed using an X-ray microanalyzer and X-ray diffraction, it was found that an intermetallic compound called AuZn ₃ was produced. Further, the alloy formed between the crystal oscillator and the lead wire had a melting point of about 610° C. according to differential thermal analysis. After sealing the glass stem and the glass case, we similarly analyzed the alloy between the crystal oscillator and the lead wire, and found that intermetallic compounds such as AuZn were formed in addition to AuZn ₃ , indicating that the mount part It was confirmed that the strength of The combinations of metal coatings represented in Table 1 are expected to have the same effects as above from a metallurgical perspective. Next, the effects obtained by the present invention will be described. (1) Mounting materials are easy to manage. In conventional crystal oscillators, the mount material was formed using alloy plating of brazing material, which was troublesome to manage, but according to the present invention, the crystal oscillator and lead wires are made of metal that is easy to plate. Since the metal on the lead wire side is melted and bonded, it is extremely easy to manage the mounting material. (2) It is possible to attach a weight for frequency adjustment on the crystal oscillator and form a metal coating on the mount at the same time. A metal coating having a thickness of 1 to 10 μm is formed on the mount portion of the crystal oscillator by a plating method. On the other hand, a metal weight is formed on the tip of the crystal oscillator, and this is trimmed with a laser to adjust the frequency. The metal of the weight for frequency adjustment is generally gold,
Since silver is used, it can be made of the same material as the metal of the mount. That is, the shapes of the mount portion and the weight portion are formed by photoetching, and gold or silver is plated thereon to form the metal coating of the weight and the metal coating of the mount portion at the same time. (3) Q value is improved. Since the alloy formed in the mount has a high melting point and a phase with high strength, the mechanical strength of the mount is increased. This allows the crystal oscillator to be more firmly fixed, thereby improving the Q value. (4) Improved aging properties. As mentioned above, glass-sealed crystal resonators have good aging characteristics because they generate less gas. The mounting method according to the present invention melts the metal on the lead wire side and alloys it with the metal on the crystal oscillator side.
The other side of the lead wire opposite the crystal oscillator has almost the same metal composition as when it was plated even after mounting. That is, the melting point is relatively low. Therefore, after mounting, a portion of the metal coating on the lead wire on the opposite side of the mount portion is melted again due to the heat generated when the glass case and the glass stem are sealed together. This molten metal acts as a getter material that adsorbs gas remaining in the glass case and improves the degree of vacuum. This further improves the aging properties of the crystal resonator according to the present invention. As described above, the present invention exhibits remarkable effects and is extremely useful in practice.

[Brief explanation of drawings]

Figure 1 is a structural diagram of a conventional crystal resonator. 2a and 2b, FIG. 3, FIG. 4, and FIG. 5 are state diagrams showing a method of manufacturing a glass-sealed crystal resonator according to the present invention. 1... Stem, 2, 2'... Lead wire, 3...
Metal ring, 4... Glass for sealing, 5... Crystal oscillation piece, 6, 6'... Inner lead wire, 7, 7'... Thin film electrode for frequency adjustment, 8... Metal case, 10, 1
0'...Lead wire, 11...Glass, 12,1
2'...Inner lead wire, 13...Glass case,
14... Graphite jig, 15... Metal coating for frequency adjustment, 16... Metal coating for mounting.

Claims (1)

[Claims] 1. In a mounting method for a glass-sealed crystal resonator in which a stem consisting of two lead wires is sealed with glass in a glass case with one end closed, the mounting part of the crystal resonator piece has a melting point of 573°C.
A first metal coating with a thickness of 1 to 10 μm is formed as described above, and a second metal coating with a thickness of 1 to 30 μm with a melting point of 573° C. or less is formed on at least the inner lead wire of the stem, which is sealed with the glass and consists of two lead wires. , said first
The metal coating and the second metal coating are heated and welded at a temperature between the melting point of the second metal coating and 573°C, and the melting point of the melted and solidified portion between the mount part and the lead wire is the lowest glass sealing temperature after mounting. A method for mounting a glass-sealed crystal resonator that is characterized by a temperature higher than 300℃.