JPS58170210A - Manufacturing method of crystal resonator - Google Patents

Abstract

PURPOSE:To obtain a highly stable crystal oscillator, by providing a sputtering mechanism for electrode film forming possible for minute adjustment in a package containing a crystal oscillator. CONSTITUTION:An electrode film made of gold is formed on both sides of a thickness slip oscillator 11 processed for spherical surface for one side, and the oscillator is contained into a package after being supported with a flexible supporting plate 15 made of phosphor bronze and external leads 16. The package consists of a metallic cap 13 and a base 14 made of an insulating material, the ridge is sealed with soldering for a seal construction. The leads 16 are sealed and fixed with a low melting point glass 17. A DC high voltage is impressed between two electrodes, an anode (the leads 16 via the plate 15) and a cathode (target electrode 18) of the crystal oscillator 11. The package is reduced into vacuum and replaced into gaseous argon. Accurate adjustement is preformed by allowing to collide argon ions from the anode accelerated with a negative DC bias voltage produced on a target 19 with the cathode, exciting target atoms and depositing sputter film (Au) on the oscillator 11.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a highly stable crystal resonator that is installed in satellite communications, submarine repeaters, etc. and requires high accuracy.

(b) Background of the technology Usually, the crystal piece used in a highly stable crystal resonator uses a thickness-shear vibration mode in which one side of a round or rectangular plate is processed into a spherical surface.

Even under harsh environmental conditions such as satellite communications and submarine repeaters, permanent long-term frequency stability as well as short-term frequency stability is required, and a crystal oscillator with fast rise characteristics is required.

As such a four-high stability crystal resonator, a two-rotation Y plate type crystal piece, such as an AT cut or an IT cut, which is formed by rotating the cutting direction from the crystal crystal axis around the optical axis, is used. Furthermore, it is used housed in a thermostatic chamber that can cope with temperature changes in the outside world, and requires stability and high performance as a vibration source.

(C) Prior Art and Problems In order to obtain a resonator with excellent electrical characteristics, a large crystal piece is required.On the other hand, as devices become more multiplexed and smaller, crystal resonators are also required to be made smaller. In this nine-thickness resonator, which is advantageous for miniaturization, the vibration displacement distribution is determined by the parameters of the crystal plate thickness (T) and the equivalent radius of curvature (R) of the spherical surface, so the circumferential Be band or harmonic vibration ( It is refined by polishing and forming a crystal piece that is excited by an overtone.

Electrode films are deposited on both sides of the formed crystal piece.

Usually, gold or silver is used for the electrode film. The final stage of adjusting the frequency of the vibrator is done by changing the thickness of the electrode film while measuring the frequency.
Figure b) shows a thickness-shear oscillator with one side spherical, figure (a) is a top view, and figure (b) is a side view.

FIG. 2 is a diagram showing the configuration of a conventional crystal resonator.

In the figure, 1 is a crystal piece, 2 is an electrode film, 3 is a metal middle layer, 4r
i-Pace, 5 is a support plate, 6 is a lead, and 7Fi glass fusion part, respectively.

Electrode films are formed on both sides of the crystal blank 1 by vapor deposition, and when a predetermined frequency adjustment is completed, the crystal blank 1 is housed in a container as a crystal resonator. The container consists of a metal cap 3 and a base 14, and has a sealed structure with a seal.

A crystal resonator (crystal piece 1) is bonded and supported by a flexible support plate 5 made of nickel silver, phosphor bronze, etc. using bonding or adhesive, connected to an external lead 6, and fused and sealed with low melting point glass. Stop. When the inside is to be evacuated, an exhaust pipe is provided on the base 4, and after the exhaust is evacuated, it is closed by pressure melting.

However, with this structure, it is impossible to adjust the characteristics after assembly.

Furthermore, since the resonator is used in an oscillation circuit system that forms a thermostatic chamber, frequency characteristic tests and adjustments are performed in the atmosphere or at room temperature using a corresponding quantitative conversion table, but this may lack reliability. Ta. It is also able to cope with changes in frequency characteristics over time caused by the elastic modulus of the electrode film, which is seen in aging characteristics.

(d) Object of the Invention The present invention addresses the above points and provides a substrate for forming an electrode film that can be finely adjusted within a container housing a crystal resonator.

The purpose is to provide a crystal oscillator with high stability.

The crystal oscillator is housed in a sealed container, set to the same conditions as the operating conditions, and precisely adjusted in a 900 million temperature bath; This is achieved by applying a voltage between the anode that holds the material and the target cathode that forms the electrode film, thereby stacking the sputtered electrode films.

(f) Embodiment of the invention FIG. 3 is a diagram showing the structure of a crystal resonator which is an embodiment of the invention. Thickness shear vibrator 11 with one side spherically processed
An electrode film made of gold (Au) is formed on both sides of the
Support plate 15 made of highly flexible phosphor bronze, etc. and external lead 1
It is supported and fixed at step 6 and placed in a container.

The container includes a metal cap 13 and a base 1 made of an insulating material.
4, and the periphery is sealed with brazing etc. to create a hermetically sealed structure.

Further, the lead terminal 16 is sealed and fixed with a low melting point glass 17 as shown in the figure.

-Target electrode 18 targeting livestock shed (Au)
It also includes a pulp control system 21 that performs gas inflow control for sealing argon gas into an exhaust port 20 that reduces the pressure inside the container to vacuum, and performs exhaust pressure reduction control.

The nine-quartz crystal resonator assembled in this way is precisely adjusted in a constant temperature bath set under the same operating conditions. Precise adjustment is performed by sputtering, which further laminates a gold (Au) film on one side of the electrode film so as to obtain a predetermined frequency characteristic.

The crystal resonator 11 is used as an anode via the lead terminal 16 and the support plate 15, and a DC high voltage is applied between the two poles of the target electrode 18 that serves as the cathode. The inside of the container is reduced to vacuum and replaced with argon gas, and the argon ions (Ar4) from the anode are accelerated by the negative DC bias voltage generated at Targetera (19) and collide with the cathode, killing the target atoms.
Precise adjustment is performed by laminating a sputtered film (Au) on the exposed vibrator 11.

In this way, by repeating sputtering in an airtight chamber and allowing image adjustment without being affected by external conditions, it is possible to obtain a highly stable crystal resonator with υ highly accurate frequency characteristics.

FIG. 4 is a block diagram showing a pulp control system according to an embodiment of the present invention.

A valve v provided in the argon gas (Ar) sealed pipe 22
6 is closed, and the crystal resonator mounting chamber 23 is evacuated. After roughing with pulp vl, use diffusion pump 24 to apply V2, V
Valve 3 is opened, pulp 1 is closed, and the rotary pump 25 is evacuated to high vacuum.

At this time, the pulp 4 is open. Pulp V3 after exhausting to constant pressure
t- Squeeze appropriately, open the argon gas flow rate adjusting pulp V@, and introduce argon gas.

A sputtered film is generated using the pulp control system configured as described above, and after the adjustment is completed, the argon gas is exhausted, the pressure is reduced to a constant pressure, and the exhaust port (see Fig. 3, 20) is sealed by dissolving it in an airtight manner. Obtaining a quartz crystal resonator 0 The applied voltage is 500 VDC, 5 mA, and sputtering is repeated for several seconds to adjust to the desired frequency. Adjustment range is approximately 15-20
ppm, and since the inside of the container is evacuated and baked to a high vacuum without being exposed to the atmosphere, the accuracy is 1 ppm.
Target electrode that can be adjusted below m (see Fig. 3, 18)
Although it was sealed with a thermoplastic resin, there was no shadow due to its characteristics, and a stability of Fi5X 10 pprrB/decade was obtained.

(2)) Effects of the Invention As has been explained in detail above, the crystal resonator of the present invention provides highly stable characteristics compared to conventional ones, and moreover, the conditions of use are approximately the same.
Since image adjustment is performed in a constant temperature bath set at

[Brief explanation of the drawing]

Figures (A) and (B) in Figure 1 show a 9-thickness resonator with one side spherical, (A) is a top view, (B) is a side view, and Figure 2 is a conventional Diagram showing the crystal oscillator configuration of w
Figure J3 is a diagram showing the configuration of a crystal oscillator according to an embodiment of the present invention, and Figure 4 is a diagram showing a valve control system pipe according to an embodiment of the present invention. In the figure, 11 is a crystal oscillator, 1
3 is a metal cap, 14 is a pace, 15 is a support plate, 16
1 is a lead terminal, 17 is a low melting point glass, 18 is a target electrode, 19 is a target, 20 is an exhaust port, 21 is a pulp control system, 22 is an argon gas filled pipe, 23 is a chamber, 24 is a diffusion pump, 25 is a rotary pump , V engineering ~
Indicates v6 pulv. Sub-4 Patent Attorney Hiroshi Matsuoka! Ko, I, )ff/Figure 1゜. 2 figures, 7 figures, 4/ Figure 4

Claims (2)

[Claims] (1) An AT-cut thickness sliding crystal resonator with one or both sides forming a spherical surface, the coarsely adjusted crystal resonator is housed in a sealed container and kept at a constant temperature set to the same conditions as the operating conditions. A method for manufacturing a crystal resonator, characterized in that the crystal resonator is precisely adjusted in a bath. (2) The container with the above-mentioned sealed structure is equipped with a vacuum exhaust system that shares an argon gas filling port, and a voltage is applied between the anode that holds the crystal resonator and the target cathode that forms the electrode film to sputter the electrode film. A method for manufacturing a crystal resonator according to claim 1, characterized in that the crystal resonator is laminated.