JPS59178011A - Piezoelectric vibrator - Google Patents

Abstract

PURPOSE:To reduce the occupied area of an oscillator by constituting integrally a capacitance serving as a load capacitance in constituting a piezoelectric vibrator and the oscillator. CONSTITUTION:A lower electrode 22 formed by using paste of Ag or Ag.Pd, a dielectric film made of SiO2 or the like, an upper electrode 24 made of Ag or Ag.Pd paste, a bump 25 and a piezoelectric vibrator 26 are formed on an alumina substrate 21. The vibrator 26 is fixed on the bump 25 by applying a conductive adhesive thereto. Thus, the vibrator is fixed in the state being floated from the film 23 or the electrode 24.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a piezoelectric vibrating device integrally provided with a load capacity required for constructing an oscillator.

Prior Art and Problems Generally, for example, a clock pulse detector used in microcomputers, as shown in FIG. 1, is known.

In the figure, 1 is a piezoelectric vibrator using a vibrating plate made of LiTaO3, 2 is an amplifier, 3 is a feedback resistor, and 4 is a load capacitance.

In such an oscillator, each member is usually formed separately and connected to form a circuit.

However, since the oscillator with this configuration occupies a large area, it puts restrictions on the miniaturization of microcomputers, and as the frequency of the clock pulse increases, it is not desirable to route the circuit for too long. isn't it.

In addition, apart from the above, the piezoelectric vibrator is mounted on an alumina substrate. In this case, the vibration of the vibrating blank plate is suppressed and it does not function as a vibrator, so the vibrating blank plate is mounted with the parts other than both ends floating above the alumina substrate.

FIG. 2 is an exploded side view of essential parts for explaining the method of mounting the piezoelectric vibrator.

In the figure, 11 is an alumina substrate, 12 is Ag or A
13 is a vibration plate made of LiTaO3, 14 is Ag
Alternatively, an electrode on the vibrating element plate (hereinafter referred to as a clip) formed by a printing method using a paste of A g - P d, ○D indicates a piezoelectric vibrator consisting of a vibrating element plate 13 and a clip 14, respectively. .

In order to mount the illustrated piezoelectric vibrator ○D on the alumina substrate 11, the clip 14 of the vibrator ○D is connected to the substrate side electrode 12.
This is done by adding a capacitance to the oscillator plate 13.
is fixed to the alumina substrate 11 with a gap maintained therebetween.

However, efforts are currently being made to miniaturize the vibrator ○D, and for example, the size of the vibrating plate 13 is 0.5 (in) in the transverse direction (width) and 4.5 in (in) in the longitudinal direction. °
[mWI] has appeared.

By the way, as it becomes smaller like this, the vibrator ○D
The work of mounting the alumina substrate 11 on the alumina substrate 11 becomes a difficult work, and in particular, it becomes difficult to form the clip 14 on the vibrating blank plate 13.

Purpose of the Invention The present invention makes it possible to integrally configure a capacitor serving as a load capacitor when configuring a piezoelectric vibrator and an oscillator, thereby reducing the area occupied by the oscillator and the number of circuit wiring for the oscillator. Furthermore, it is also possible to facilitate the work of mounting the piezoelectric vibrator on the substrate and to reduce the number of steps.

Examples of the invention FIG. 3 is a cutaway side view of essential parts of an embodiment of the present invention.

In the figure, 21 is an alumina substrate, 22 is Ag or A
23 is a dielectric film made of, for example, 5i02, Si3N+, SiOxNy, or TlO2, and 24 is Ag or A.
The upper electrode is formed using g-Pd paste, 25 is a hump made of, for example, Ag or Ag-Pd paste, and 26 is a piezoelectric vibrator.

In this embodiment, the lower electrode 22 and the upper electrode 24 are formed by screen printing, dried, and then baked to complete the process. Further, the dielectric film 23 may be formed by, for example, chemical vapor deposition (CVD).
r depositionOn method) and photolithography technology. Furthermore, the hump 25 can be formed by applying a screen printing method. Incidentally, in the screen printing method, 312 pairs of humps 25 are printed at a time.
can be formed.

Needless to say, in the above structure, the lower electrode 22, the dielectric film 23, and the upper electrode 24 form two capacitors.

Now, in order to mount the vibrator 26, for example, by applying a conductive adhesive onto the bump 25 and fixing it, the vibrator 26 will be fixed in a raised state from the mounting surface, that is, the dielectric film 23 or the upper electrode 24. be done.

If the transducer 26 is not fitted with a lip as in the prior art, the manufacturing process is considerably shortened.

In the above configuration, if the lower electrode 22 is grounded, both ends of the vibrator 26 are grounded via the capacitance, and if an amplifier or feedback resistor is connected to this, the oscillator or Easily configured.

Effects of the Invention The piezoelectric vibrating device of the present invention has a structure in which a lower electrode, a dielectric film, an upper electrode, a bump, and a piezoelectric vibrator are sequentially formed on a substrate, and the piezoelectric vibrator does not need to be formed with a conventional clip. Since the transducer can be mounted with most of it floating using the hump, it can fully function as a vibrator, and since the clip is not formed,
Even when miniaturized, it is extremely easy to manufacture and handle. Furthermore, the capacitance formed by the lower electrode, dielectric film, and upper electrode can be used as a load capacitance when manufacturing an oscillator, and is therefore effective in making the oscillator compact.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of the main part of an oscillator, Fig. 2 is an exploded side view of the main part of a piezoelectric vibrating device to explain a conventional example equipped with a vibrator, and Fig. 3 is a main part g+! of an embodiment of the present invention! Cutting (side view) In the figure, 21 is an alumina substrate, 22 is Ag or A
The lower electrode 23 is made of g.Pd, 5102 or Si.
A dielectric film made of 3N4, S1OxN, or TiO2, 24 an upper electrode made of Ag or Ag-Pd, 25 a hump made of 8g or Ag-Pd paste, and 26 a vibrator. Patent Applicant Fujitsu Co., Ltd. Representative Patent Attorney Kugobe Tamamushi (3 others) Figure 1 Figure 2 0 Figure 3 7

Claims (1)

[Claims] A lower electrode formed on a substrate, a dielectric film formed on the electrode, an upper electrode formed on the dielectric film, a hump formed on the upper electrode, and a piezoelectric fixed on the hump. A piezoelectric vibrating device comprising a vibrator.