JPS589416A - Production of container for quartz oscillator - Google Patents

Abstract

PURPOSE:To realize a large-quantity and simultaneously vacuum sealing process, by using the glass for a case material. CONSTITUTION:The tin oxide of about 100Angstrom -1mu is formed on at least a single side of the glass by a CVD process. Then the unnecessary area of the tin oxide film 10 is removed by a photoetching process, etc. The remaining film 10 is used as a mask to etch the glass, and a recessed part is formed to the glass. The unnecessary area of the film 10 is removed again by a photoetching process, etc., and an electrode is formed so as to leave the film 10 only at the areas shown by the oblique lines. In such way, the cost of the materials is reduced and the large- quantity and simultaneous process is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a glass case for a thin crystal resonator.

Conventionally, a crystal resonator is manufactured by brazing a crystal tuning fork 1 to a lead terminal 3 of a hermetic seal called a plug 2, and press-fitting a metal case 4 in a vacuum, as shown in FIG. Although most crystal resonators are manufactured in this manner, some crystal resonators are manufactured as shown in FIGS. 2 and 3 due to the demand for thinner crystal resonators. Figure 2 α shows a crystal vibration in which a crystal tuning fork 5 with a frame as shown in Figure 2 is sandwiched between an upper case 6 and a lower case 7 made of crystal etched into a box shape and sealed using a brazing material. It is a child. FIG. 3 shows a crystal resonator in which a crystal tuning fork 1 is mounted on a drawn ceramic case 8, and the glass plate 9 and the ceramic case 8 are sealed with a brazing material. ``The crystal resonator shown in Figure 1 has a tall plug and case, and is cylindrical, so there is a limit to how thin it can be made, which is the width of a crystal tuning fork. In order to improve this, the crystal resonators shown in Figures 2 and 3 were devised, but the former uses expensive crystal for the case material, so although it was successful in making it thinner, it was extremely expensive. It is. The latter has the disadvantage that it is inferior to a cylindrical crystal resonator in practical terms due to the low reliability of ceramics in vacuum, the difficulty of ceramic molding, and the difficulty of fixing (hereinafter referred to as mounting) the crystal tuning fork. Ta.

The present invention improves the above-mentioned drawbacks and provides a method for manufacturing an inexpensive and thin crystal resonator.
As a result of examining the reason why the crystal resonator of 2005 was unable to achieve the goal of reducing costs, we came to the following conclusion.

About the crystal oscillator shown in Figure 2 ■ An expensive crystal was used for the case. When using a framed crystal tuning fork, it is necessary to match the thermal expansion coefficients of the case and tuning fork.

■The case was etched using chrome and gold vapor deposition film as a mask. Since crystals are etched with a highly concentrated fluoride solution, the etching mask must be made of chromium or gold.

■Using framed crystal. When removing a crystal tuning fork from a piece of crystal, the frame is also processed at the same time, which makes the number of tuning forks that can be removed small and expensive.

■Crystal with etching anisotropy is used for the case. Although the etching speed of crystal is different in the X, Y, and Z axis directions, the two thickness directions of the case are particularly susceptible to etching, and if there is a defect in the crystal, the front and back of the case will be etched through, making it impossible to maintain a vacuum.

Regarding the crystal oscillator shown in Figure 3: - Ceramic has low airtight reliability. Since ceramic is a sintered body of fine particles, airtightness cannot be maintained unless it is thicker than a certain level.

■Mounting work is difficult because the mount part is inside the ceramic case.

■Poor ceramic flatness. Since ceramics are fired after printing and drawing, the finished product has poor flatness. For this reason, it is not possible to seal many ceramic cases in sheet form at once, so each product must be processed individually.

In order to improve the above-mentioned drawbacks, the present inventor manufactured a crystal resonator with the following configuration.

(1) Use glass for the case.

(2) The case is etched using tin oxide as a mask.

(8) Multiple cases are manufactured simultaneously from flat glass.

(4) The case is box-shaped and does not have double steps like the cellar-built case 8 in Figure 3.

(5) The tin oxide film used as the glass etching mask is used as a lead wire to lead the electrode of the crystal tuning fork to the outside.

Next, the present invention will be described in detail according to examples.Example Thickness [L3m, 50 cryo angle D263 glass (trade name: Nijiyoto Co., Ltd., components: all by weight ratio, f910.68
%, Na107%s people 1103 4%, 106
%, Ba0a8%, B,0.9%, ZnO4%) were sufficiently washed and dried, and then tin oxide (SnO,)1
0 was formed to a thickness of 1000×. A photoresist 11 is applied on top of this and exposed.

It was developed to form a pattern as shown in FIG.

The shaded area is the remaining part of the resist, and FIG. 4(α) is the pattern for the upper case, and FIG. 4(h) is the pattern for the lower case. Next, a solution containing 200 f/l of citric acid, 50 t/l of hydrochloric acid, and 109/ml of metallic chromium was heated to 60°C, and the above glass was immersed in this solution for 10 seconds to form the diagonal lines in Figure 4. The remaining tin oxide was removed. Next, this glass was 49%H
Etching was performed at 60° C. for 50 minutes with an etching solution containing 800 Q/l of Fs solution and 500°/Z of glycerin. A cross section of the glass after etching is shown in FIG. The etching depth of the glass was 110μ. Note that since the tin oxide 10 was formed only on one side, the other surfaces were uniformly etched, and the thickness of the glass was 19 mm at the unetched area.
It was 0μ. After etching, the surface of the tin oxide and the surface of the etched glass were observed, and it was found that the tin oxide was hardly etched, while the etched surface of the glass was very smooth and the etching depth was uniform. It can be seen that the ratio of etching rates between tin oxide and alkali zinc borosilicate is more than 1000 times. Other experiments have confirmed that soda glass, which is more easily etched, is 5000 times more effective. The thickness of tin oxide as a glass etching mask is 100 to 1 μm, preferably 300 to 300×. If the thickness of tin oxide is less than 1 oo'j-, there will be too many pinholes and it cannot be used as an etching mask, and depending on the glass material, it may not be possible to obtain a sufficient etching rate selectivity. On the other hand, if the thickness exceeds 1 μm, fine cracks are likely to occur in tin oxide, and the amount of side etching during patterning of tin oxide is large, making it difficult to use. When the thickness is between 300 and 3000X, tin oxide is dense with almost no pinholes or cracks.

After etching the glass, the lower case shown in FIG. 4(h) is patterned using a photo-etching method, and
As shown in Figure (α), the electrode is formed so that the tin oxide film remains only in the shaded area. Next, a low melting point glass frit 12 was printed on the convex portion of the lower case glass as shown in FIG. 6Cb'), and then baked at 400° C. for 20 minutes. As the low melting point glass paste, I, A200A (trade name: manufactured by Yoshikawa Kako) was used. It has a softening point of 385°C. Next, nickel plating 13 was selectively and closely adhered to the tin oxide 10 only on the tin oxide 10 using a commercially available pretreatment solution and an electroless nickel plating solution on the lower case to which the low melting point glass was attached. The sensitizer is Shipley 44 (trade name) and the accelerator is Shipley 19.
(Product name), electroless nickel plating solution is Schumer 86
510 (trade name: manufactured by Nippon Kanigen) was used. In order to improve the mountability of the crystal tuning fork and the solderability of external terminals, gold plating 14 was applied on the nickel using an electroless gold plating solution Atomex (product name 8 manufactured by Nippon Engelhardt). A cross section of the lower case is shown in FIG. Next, as shown in Fig. 8, after brazing the crystal tuning fork 1 plated with brazing material to the mount part, the upper case 15 from which the tin oxide has been peeled off is stacked in a vacuum as shown in the figure, and heated to 475°C for 30 minutes. The low melting point glass frit was melted and sealed by heating for a minute.

The thickness of the crystal resonator manufactured in this way is 1llL6
It was a struggle.

Next, the effects obtained by the present invention will be described.

(1) Materials are inexpensive.

Not only glass is used, but the glass material is hardly selected, so inexpensive glass can be used.(2) Large-scale simultaneous processing is possible.

When using crystal as a case, the number of processes is limited depending on the size of the raw crystal, and it also requires a polishing process that increases the cost considerably. Furthermore, since ceramic has poor flatness, it is impossible to process large sheets simultaneously in large quantities.

On the other hand, in the present invention, since glass is used as the case material, it is possible to easily obtain a large sheet with good flatness without polishing and at low cost.

(8) Glass etching masks are inexpensive.

When etching glass with high precision, vapor-deposited films of chromium and gold are generally used. Gold is used as the hydrofluoric acid-resistant metal, but since gold alone does not provide good adhesion to glass, chromium is used as the base. Increased man-hours due to the use of two-layer metal and the use of expensive gold;
Above all, applying the film in a vacuum is the cause of the high cost. In the present invention, a single layer of tin oxide can be used as an etching mask. Further, since tin oxide can be formed continuously and very easily by the OVD method, the glass etching mask can be formed at low cost.

(4) High airtight reliability.

When crystal is etched during case manufacturing, through-holes are likely to occur due to lattice defects, resulting in a low yield.

Additionally, ceramics inherently have poor airtight reliability. In the present invention, since glass is used as the material, airtightness is extremely high.

(5) Glass etching masks can also be used for electrodes.

Since the tin oxide used as a mask for glass etching in the present invention has electrical conductivity, it can be used as an electrode to guide the electrical signal extracted from the crystal tuning fork to the outside of the container. Tin oxide does not change its performance even if a low-melting glass frit that seals the glass is placed on top of it, but a similar transparent electrode material, indium oxide (N*OS), becomes conductive when heated with a low-melting glass frit. Lose. According to the present invention, tin oxide used as an etching mask can be used again as an electrode material, resulting in a cost reduction effect in which the process is shortened.

As described above, the method for manufacturing a container for a crystal resonator according to the present invention is extremely superior to the conventional method for manufacturing a cylindrical crystal resonator, since it uses inexpensive materials and enables simultaneous vacuum sealing in large quantities. This is a practical invention.

[Brief explanation of drawings]

Fig. 1 shows a conventional cylindrical crystal resonator, Fig. 2 shows a perspective view (' α) and a plan view of a crystal piece of a thin crystal resonator whose case material is crystal (Ch), and Fig. 3 shows a ceramic and glass crystal resonator. The thin crystal resonator used as the case material is shown. Figure 4 is the upper case pattern diagram (α) and lower case pattern diagram (b) according to the present invention, Figure 5 is the cross section after glass etching, and Figure 6 is the electrode wiring @ (α) and the low melting point. Figure 7 is a cross-sectional view after applying electroless nickel and gold on tin oxide, and Figure 8 is a diagram after the crystal tuning fork mount and upper case are vacuum sealed. . Applicant: Shikiwa Seikosha Co., Ltd. Agent, Patent Attorney: Mogami
Figure + i7 Figure 1,000 Figure 8

Claims (1)

[Claims] In a method for manufacturing a crystal resonator in which a crystal tuning fork is vacuum-sealed between two pieces of glass having a concave portion on one surface, tin oxide (S n Ox ) of 100X or more and 1μ or less is formed on at least one side of the glass, and then a photo After removing unnecessary parts of the tin oxide film using an etching method, etc., etching the glass using the remaining tin oxide film as a mask to form four parts that house the crystal tuning fork in the glass, and then oxidizing again using a photo etching method etc. A method for manufacturing a container for a crystal resonator, characterized by removing unnecessary portions of tin and using the remaining tin oxide film as a conductive electrode to the outside of the crystal tuning fork.