JPH044604A - Sealing base for electric component - Google Patents

Abstract

PURPOSE:To improve the mechanical strength and machinability and to enhance the protection effect of the component by making a sealing base sealing the component with a ceramic baked at a low temperature. CONSTITUTION:Sealing bases 5a, 5b located on both sides of a piezoelectric resonator 1 are made of a ceramic baked at a low temperature. Moreover, space forming recessed parts 6a,6b are formed to a position of the sealing bases 5a, 5b corresponding to the vibration region of the piezoelectric resonator 1 respectively. Then the piezoelectric resonator 1 and the sealing bases 5a, 5b are bonded by adhesives 7a, 7b applied to the circumference. Thus, the space forming recessed parts 6a, 6b are easily formed, and excellent chamferring, end face polishment and cutting performance arc attained. Thus, the manufacture cost of the sealing bases 5a, 5b is reduced and excellent mass-productivity is attained. Furthermore, since less transparency and excellent sealing performance are attained, the piezoelectric resonator 1 is protected with the sealing bases 5a, 5b while securing the space.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sealing substrate for electronic components that has excellent workability.

[Prior Art and Problems to be Solved by the Invention] Hitherto, electronic components having a structure in which an element is sealed with a sealing substrate, such as a chip-type piezoelectric component, have been known. This chip type piezoelectric component is
Usually, there is a piezoelectric resonator in which a counter electrode part and an extraction electrode part are formed on a piezoelectric substrate, a sealing substrate bonded to both sides of the piezoelectric resonator with an adhesive, etc., and a space formed in the sealing substrate. It has a recess for use. This sealing substrate is required to have high mechanical strength in order to protect the piezoelectric resonator.

Therefore, a ceramic plate made of alumina or the like has conventionally been used as a sealing substrate.

However, such a sealing substrate has high strength and high density, and also has high hardness and lacks toughness, so it lacks workability and mass productivity.

Furthermore, the strength of the piezoelectric resonator is lower than that of a high-strength, high-hardness sealing substrate. Therefore, in the manufacturing process, when sealing substrates are laminated and bonded on both sides of a piezoelectric resonator and the resulting laminate is cut using a blade suitable for the sealing substrate to produce chip pieces, The piezoelectric resonator is easily damaged, the yield is reduced, and the cost of the chip-type piezoelectric component is increased.

On the other hand, in order to improve processability and mass productivity, it is also possible to use a sealing substrate made of a soft material. However, since the sealed IF substrate made of a soft material has low mechanical strength, it is difficult to protect the piezoelectric resonator while securing space.

As described above, with conventional sealing substrates, it is difficult to achieve both mechanical strength and workability.

Therefore, an object of the present invention is to provide a encapsulation substrate for electronic components that has excellent mechanical strength and workability, and has an excellent element protection effect.

[Means and Effects for Solving the Problems] The present invention solves the above-mentioned problems by using a sealing substrate for electronic components in which the sealing substrate for sealing elements is made of ceramic fired at a low temperature.

Since this sealing substrate is made of ceramics fired at a low temperature, it can be easily processed mechanically. Furthermore, since the ceramic raw material is sintered by low-temperature firing, the sealing substrate is integrated.

[Example] The present invention will be explained in more detail below based on the accompanying drawings.

FIG. 1 is an exploded perspective view showing an electronic component according to an embodiment of the present invention, and FIG. 2 is a sectional view of the electronic component shown in FIG. 1.

In this example, a chip-type piezoelectric component is shown as the electronic component.

The piezoelectric resonator (1) of the chip-type piezoelectric component has a piezoelectric substrate (2
), counter electrode parts (3a) (3b) formed opposite to both sides of the piezoelectric substrate (2), and the counter electrode part (3a)
It is comprised of an input extraction electrode part (4a) and an output extraction electrode part (4b) extending in opposite directions from (3b), respectively.

Sealing substrates (5a) (5b) on both sides of the piezoelectric resonator (1)
) is made of low-temperature fired ceramic. Also, among the sealing substrates (5a) and (5b), the piezoelectric resonator (1)
Space-forming recesses (6a) and (6b) are formed at locations corresponding to the vibration regions, respectively.

Furthermore, as shown in FIG.
(7b) is joined and sealed.

Furthermore, the input extraction electrode part (4a) and the output extraction electrode part (4b) are formed at corresponding locations on the piezoelectric resonator (1) and the sealing substrate (5a) (5b), respectively. The electrode part (8a) and the output external electrode part (8b) are electrically connected.

In a chip-type piezoelectric component having such a structure, a sealing substrate (5
a) Since (5b) is made of ceramic fired at a low temperature, the space-forming recesses (6a) and (6b) can be easily formed, and it is excellent in surface raising, end face polishing, and cutting performance. Therefore, it is excellent in mass production, and the sealing substrate (5a) (
5b), and thus the manufacturing cost of chip-type piezoelectric components can be reduced. Furthermore, since the sealing substrates (5a) and (5b) are made of ceramic sintered by firing, they not only have the mechanical strength necessary to protect the piezoelectric resonator (1), but also have low transparency. , and has excellent sealing properties. Therefore,
The piezoelectric resonator (1) can be protected by the sealing substrates (5a) and (5b) while maintaining space.

Furthermore, since the low-temperature fired ceramics constituting the sealing substrates (5a) (5b) are more porous than the high-temperature fired ceramics, the following effects can be achieved.

(a) Since the thermal conductivity is low, the heat insulation property is high, and it is possible to suppress external thermal shock from acting on the piezoelectric resonator. (b
) External electrode (8a) formed on the outer surface of the sealing substrate (5a> (5b) by a film forming method such as vapor deposition or sputtering)
(8b) and the sealing substrate (5a) (5b).
a) Maintains conductivity with (8b) over a long period of time. Therefore, in combination with the effect (a), the reliability of resonance characteristics is improved.

(C) Even if the outer surface of a chip-type piezoelectric component is marked, the marking film can be prevented from falling off, and the marking effect can be maintained for a long period of time.

Note that the sealing substrate is obtained by firing the ceramic raw material at a temperature lower than a normal firing temperature and at a temperature at which they can be sintered together. The firing temperature can be selected depending on the type of ceramic raw material, but it is 50 to 30 degrees higher than the normal firing temperature.
It is carried out at a temperature as low as 0°C. More specifically, taking the case of a commonly used alumina substrate as an example, the conventional high-strength, high-hardness alumina sealing substrate has the following characteristics:
Usually, it is manufactured by firing alumina at about 1500°C. The alumina sealing substrate obtained by such high-temperature firing has a strength of 4500 r/cn.
The density is about 3.82 g/cnf.

On the other hand, a sealing substrate made of ceramic fired at a low temperature is produced by heating alumina at a temperature below 1500°C, e.g.
It is obtained by firing at about 00 to 1450°C, preferably about 1400°C.

The alumina sealing substrate obtained by low-temperature firing has a strength of about 2000 kg/ctA and a density of 3.60.
It is about g/-.

In addition, when we compared the workability of an alumina sealing substrate fired at a high temperature of 1500°C and an alumina sealing board fired at a low temperature of about 1400°C, we found that the alumina sealing substrate fired at a low temperature was superior to that fired at a high temperature. 6 than the alumina sealing substrate.
Surface processing at twice the speed (lap machine manufactured by Hamai Co., Ltd., 5B
It can also cut at a speed of 20 mm/min. Although the alumina sealing substrate fired at a low temperature has a slightly lower strength than the alumina sealing substrate fired at a high temperature, it still has the strength necessary to protect the piezoelectric resonator. Furthermore, the alumina sealing substrate fired at a low temperature exhibits sealing properties between paths and the like compared to the alumina sealing substrate fired at a high temperature, and is highly reliable.

Furthermore, the alumina sealing substrate obtained by low-temperature firing is
Since the dielectric constant is usually about 7 to 8, there is no deterioration in the characteristics of the piezoelectric component.

Note that if it is necessary to form a recess or the like in the sealing substrate, the recess may be formed simultaneously with the molding of the ceramic raw material or by molding after firing.

Further, the recessed portion of the sealing substrate is not necessarily required.

That is, the space between the sealing substrate and the piezoelectric resonator is filled with the adhesive (7a) that functions as a spacer, without depending on the recess.
(7b) It may be ensured by the thickness of the layer.

Furthermore, the sealing substrate with excellent workability is not limited to the above-mentioned recess, but may also include, for example, an accommodation recess having a mounting step on which a piezoelectric resonator can be placed and accommodated.

The electrode structure of the piezoelectric resonator is not particularly limited as long as at least one pair of opposing electrode portions is formed on the piezoelectric substrate.

For example, a piezoelectric resonator includes at least one pair of opposing electrode sections facing each other on one surface of a piezoelectric substrate, an extraction electrode section extending from the opposing electrode section, and the above-mentioned opposing electrode section on the other surface of the piezoelectric substrate. It may be configured by a common electrode part formed at a corresponding location and a grounding lead electrode part extending from the common electrode part.

The present invention is not limited to piezoelectric components, but can also be applied to various electronic components in which elements are required to be sealed.

[Effects of the Invention] As described above, according to the present invention, since the sealing substrate for sealing the element is made of ceramic fired at a low temperature, it has excellent mechanical strength and workability, and has an excellent protection effect for the element. There is.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing an electronic component according to an embodiment of the present invention, and FIG. 2 is a sectional view of the electronic component shown in FIG. 1. (1) Piezoelectric resonator, (5a) (5b) Sealing substrate Applicant Murata Manufacturing Co., Ltd.

Claims (1)

[Claims] A sealing substrate for electronic components, characterized in that the sealing substrate for sealing an element is made of ceramic fired at a low temperature.