JPH11142430A - Electronic part and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic part that is capable of maintaining a predetermined degree of vacuum and a predetermined purity of decompressed inert filler gas, and an electronic part manufacturing method that is capable of sealing a vent hole with a filler in a sealing atmosphere of a vacuum tank without causing the intrusion of the gas produced out of the melted filler into the cavity. SOLUTION: A support substrate 14c is mounted thereon with a sensing part 25, and a sealing substrate 10 is formed with a concavity 13, a vent hole 11b through part of the concavity 13, and a depression 11c partly overlapping with the vent hole 11b in the surface. The obtained support substrate 20 and the sealing substrate 10 are subjected to anodic or direct welding in a vacuum or a decompressed inert gas to form a cavity 13a enclosing the sensing part 25, and the depression 11c is filled with a filler, which is melted to seal the vent hole 11b and thus seal the cavity 13a hermetically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component, such as an acceleration sensor or a gyro sensor, in which an object to be sealed such as a sensing unit must be kept under reduced pressure, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A conventional electronic component such as a gyro sensor and a method of manufacturing the same are disclosed in Japanese Patent Laid-Open No. 7-1 as means for sealing a cavity in which a sensing part is housed.
There is an invention disclosed in Japanese Patent Publication No. 06890. According to the present invention, as shown in FIG. 13, a gas vent hole 22 is formed in a sealing substrate 21, a heat-meltable spherical sealing material 23 is inserted into the gas vent hole 22, and the sealing material 23 is heated. The cavity was sealed by melting and closing the gas vent hole 22.

[0003]

However, in the conventional method for manufacturing an electronic component, when the gas vent hole 22 is sealed in a vacuum chamber, a gas such as a solvent generated when the sealing material 23 is melted, As indicated by the arrow, the electronic component manufactured by this conventional manufacturing method after entering the cavity could not obtain a sufficient degree of vacuum. In addition, even when an inert gas is sealed in the cavity and sealed, the electronic components manufactured by this conventional manufacturing method reduce the purity of the inert gas under reduced pressure due to the gas generated from the sealing material. I was

Accordingly, the present invention is directed to an electronic component that maintains a predetermined degree of vacuum and a predetermined purity of an inert gas filled under reduced pressure, and a gas generated from a molten sealing material when the gas vent hole is sealed with the sealing material. An object of the present invention is to provide an electronic component capable of sealing a gas vent hole in a sealing atmosphere of a vacuum chamber without gas entering a cavity, and a method of manufacturing the electronic component.

[0005]

According to a first aspect of the present invention, there is provided an electronic component, wherein a first substrate and a second substrate are joined to form a cavity therebetween, and the cavity is sealed. A stationary material is accommodated, a gas vent hole communicating with the cavity is formed in one of the first substrate and the second substrate, and a dent that partially overlaps the gas vent hole is formed on the surface of the substrate, The gas vent hole is sealed with a sealing material straddling the gas vent hole and the depression.

According to the present invention, a gas vent hole formed in either the first substrate or the second substrate straddles a dent formed partially overlapping the gas vent hole, and is sealed with a sealing material. The cavity is closed with the same pressure as in the sealing atmosphere. As a result, the degree of vacuum in the cavity or the purity of the gas under reduced pressure is improved, and vibration of the object to be sealed is not suppressed.

According to a second aspect of the present invention, a support substrate having a sensing portion and a sealing substrate having a concave portion are joined to form a cavity for accommodating the sensing portion. A gas vent hole leading to the concave portion is formed, and a dent is formed on the outer surface of the sealing substrate so as to partially overlap the gas vent hole, and a sealing material is filled in the gas vent hole and the dent. The gas vent hole is sealed and the cavity is sealed.

According to the present invention, the cavity formed between the supporting substrate and the sealing substrate is formed by using the concave portion of the sealing substrate. The gas vent hole penetrates the sealing substrate and communicates with the recess. The gas vent hole formed in the sealing substrate straddles the depression formed partially overlapping the gas vent hole, and is sealed with the sealing material, and the cavity is sealed with the pressure in the sealing atmosphere. . As a result, the degree of vacuum in the cavity or the purity of the reduced-pressure sealing gas is improved, and the vibration of the sensing unit is not suppressed, and the sensitivity is excellent.

According to a third aspect of the present invention, there is provided an electronic component manufacturing method, wherein an object to be sealed is disposed on at least one of a first substrate and a second substrate. Forming a gas vent hole penetrating the substrate in one of the substrates, forming a depression partially overlapping the gas vent hole in the surface of the substrate, and forming the first substrate and the second substrate in a vacuum or in a reduced pressure inert gas. The second substrate is joined to form a cavity communicating with the gas vent hole, and the cavity is accommodated with the object to be sealed, and a sealing material is loaded into the recess, and the sealing material is The gas vent hole is sealed with a sealing material that has melted and has flowed out of the depression.

According to the present invention, the first substrate and the second substrate are anodic-bonded or directly bonded in a vacuum or a reduced-pressure inert gas. In this joining, gas is generated from the joining surface and flows into the cavity. The gas that has flowed in is discharged into the vacuum chamber through a gas vent hole that communicates with the cavity.

Further, the first substrate and the second substrate which are bonded are sealed with a gas vent hole in a vacuum chamber or in a reduced pressure inert gas. This sealing is performed by heating and melting the heat-meltable sealing material placed in the depression, and flowing the molten sealing material to the gas vent hole to be cured. When the sealing material is melted, the solvent contained in the sealing material is vaporized to generate gas. Most of the generated gas diffuses directly into the vacuum chamber, and also diffuses into the vacuum chamber through a gap between the molten sealing material and the vent hole.

As described above, the sealing material melted in the depression stays in the depression for a moment, and during this time the gas is diffused into the vacuum chamber as described above, so that the gas entering the cavity is reduced. Become. Therefore, it is possible to prevent a decrease in the degree of vacuum in the cavity and a decrease in the purity of the reduced-pressure sealed inert gas.

According to a fourth aspect of the present invention, there is provided an electronic component manufacturing method, wherein a sensing portion is formed in a support substrate, a concave portion is formed in a sealing substrate, and a gas vent hole communicating with the concave portion is formed in the sealing substrate. Then, a dent that partially overlaps the gas vent hole is formed on the surface of the sealing substrate, and in a vacuum or a reduced-pressure inert gas, the support substrate and the sealing substrate are joined to form a cavity by the concave portion. Forming and accommodating the sensing portion in the cavity, loading a sealing material in the recess, sealing the gas vent hole with the sealing material that melts the sealing material and flows out of the recess. Is what you do.

According to a third aspect of the present invention, in the third aspect, the first substrate is a sealing substrate having a concave portion for providing a cavity, and the second substrate is a sensing portion as an object to be sealed. Although the present embodiment is different from the third aspect in that the supporting substrate is provided, the operation is substantially the same as that of the third aspect.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing an angular velocity sensor will be described as one embodiment of a method for manufacturing an electronic component according to the present invention.

First, a method for manufacturing the sealing substrate 10 will be described with reference to FIGS. In FIG. 1, a photoresist 12a is formed on the entire surface of a rectangular Pyrex glass substrate 11 by photolithography, and a frame-shaped photoresist 12b is formed on four sides of the back surface.

In FIG. 2, photoresists 12a, 1
Using the 2b as a mask, a concave portion 13 capable of accommodating a sensing portion described later is formed in the Pyrex glass substrate 11 by wet etching using hydrofluoric acid. Thereafter, the photoresists 12a and 12b are peeled.

In FIG. 3, a Pyrex glass substrate 1
A part of one corner of the top surface 11a of the concave portion 13 has, for example, C
The gas vent hole 1 penetrates the substrate 11 using an O ₂ laser.
Open 1b. As shown in FIG. 9, the diameter of the gas vent hole 11b on the concave portion 13 side of the Pyrex glass substrate 11 is smaller than the hole diameter on the front surface side.

In FIGS. 4 and 5, similarly, a CO ₂ laser is used to form a depression 11c on the surface of the Pyrex glass substrate 11, that is, the surface on which the recess 13 is not formed, which partially overlaps the gas vent hole 11b. . Thereby, the sealing substrate 10 as the first substrate is completed.

Incidentally, these gas vent holes 11b and recesses 1
1c may be formed by using a photo-etching technique.

Next, referring to FIG. 6 and FIG.
0 will be described. First, in FIG.
SOI having a three-layer structure of upper silicon substrate 14a, middle silicon oxide film 14b, and lower silicon substrate 14c
(Silicon On Insulator) A substrate 14 is prepared. Using a photolithography technique, a photoresist 14d is patterned on the SOI substrate 14 in a planar shape (sensor structure) of the sensing unit 25 of the angular velocity sensor shown in FIG. Then, using RIE (Reactive Ion Etching), sulfur hexafluoride (SF ₆ ) as an etching gas, and a photoresist 14 d as a mask, anisotropically with respect to the silicon substrate 14 a until the middle silicon oxide film 14 b is seen. Vertical processing is performed by applying a reactive etching. afterwards,
The photoresist 14d is stripped.

In FIG. 7, this FIG.
FIG. 14 shows a line cross section and a second substrate, that is, a lower silicon substrate 14c. A photoresist is patterned on a fixed portion (white portion in FIG. 12), and BHF (buffa hydrofluoric acid) is Using an etchant, the silicon oxide film (sacrifice layer) 14b under the movable portion (the point gathering portion in FIG. 12) is removed by etching, and then a space 15 is formed. This space 15 allows the movable part to freely vibrate. Thereafter, the photoresist is removed, and after washing and drying, the sensing unit 25 as an object to be sealed shown in FIG. 12 is completed.

Next, the structure of the sensing unit 25 shown in FIG. 12 will be described.

The sensing section 25 detects an angular velocity by detecting a Coriolis force. Reference numeral 1 denotes a rectangular plate-shaped vibrating body, and movable handles 2a and 3a extend at right angles and in both directions from both ends in the longitudinal direction. This movable pattern 2
One ends of the U-shaped support beams 6a and 7a are connected to the tips of a and 3a, and the other ends are connected to the fixing portions 6 and 7.

On the outer surfaces of the movable handles 2a, 3a, a plurality of parallel movable comb electrodes 2b, 3b (point set portions) are formed at right angles. Also, a plurality of fixed comb-teeth electrodes 2c, 3c facing the movable comb-teeth electrodes 2b, 3b to form a capacitor,
Fixed electrodes 2d and 3d (white background portions) that are perpendicularly coupled to c and 3c are formed. The movable comb electrode 2b and the fixed comb electrode 2c on the left side of the vibrator 1 and the movable comb electrode 3b and the fixed comb electrode 3c on the right side form the drive electrode units 2 and 3, respectively.

The movable comb electrodes 2b, 3 of the drive electrode sections 2, 3
Since b and the vibrating body 1 are integrally formed by the silicon substrate 14a, their vibration displacements are the same.

A plurality of movable handles 4a, 5a extend in a direction perpendicular to each side from both sides of the vibrator 1, and movable comb electrodes 4b, 5b are formed on both sides thereof.
Also, fixed comb electrodes 4c, 5c facing the movable comb electrodes 4b, 5b to form a capacitor, fixed handles 4d, 5d connected thereto, and fixed electrodes 4e connected to these, 5e and their extraction electrodes 4f, 5f
Are formed. The upper movable comb electrode 4b and the fixed comb electrode 4c on the upper side of the vibrating body 1 and the lower movable comb electrode 5b and the fixed comb electrode 5c on the lower side are connected to the detection electrode portions 4, 5 respectively.
Is configured. In addition, the movable part shown by the point set part, that is, the vibrating body 1, the movable handles 2a, 3a, 4a, 5a, the U-shaped support beams 6a, 7a, and the movable comb electrodes 2b, 3b, 4b, 5b,
The sacrificial layer portion of the lower silicon oxide film 14b is removed, and the silicon oxide film 14b floats away from the silicon substrate 14c (see FIG. 8), and can freely vibrate.

Next, the operation of the sensing unit 25 shown in FIG. 12 will be described. The movable comb electrode 2 of the drive electrode unit 2
b and the fixed comb electrode 2c, and between the movable comb electrode 3b and the fixed comb electrode 3c of the drive electrode unit 3, for example,
An alternating voltage having a peak value of 0 V and 5 V is applied alternately. Then, the movable comb electrodes 2b and 3b are alternately attracted to the fixed electrodes 2d and 3d so as to enlarge the area facing the fixed comb electrodes 2c and 3c by the electrostatic force, and the vibrating body 1 is moved by X.
Vibrates in the axial direction.

As described above, if the sensing unit 25 rotates around the Z axis while the vibrating body 1 is vibrating in the X axis direction, vibration due to Coriolis force appears in the Y axis direction,
The vibrating body 1 also vibrates in the Y-axis direction. Then
One of the capacitances of the detection electrode units 4 and 5 on both sides of the vibrating body 1 increases, and the other decreases. By subjecting the increased / decreased capacitance to voltage conversion and differential amplification, the vibration component in the X-axis direction is removed, the vibration component due to the Coriolis force in the Y-axis direction is extracted, and the rotational angular velocity and its integration are integrated. The angle can be determined.

Next, sealing of the gas vent hole 11b will be described. The following steps are performed in a vacuum chamber.
8, the sealing substrate 10 shown in FIG. 4 is superimposed on the support substrate 20 shown in FIG.
The anodic bonding is performed with V, and the supporting substrate 20 and the sealing substrate 10 are bonded. Then, the cavity 13 a for accommodating the sensing unit 25 is formed by the concave portion 13 of the sealing substrate 10.

At the time of this anodic bonding, oxygen gas generated from the bonding surface flows into the cavity 13a, and the flowed gas is discharged from the gas vent hole 11b to the vacuum chamber.

Next, in FIG. 9, a spherical sealing material 16 made of a solder alloy is loaded into the depression 11c, and heated by, for example, an infrared furnace to melt the sealing material 16. The melted sealing material 16 momentarily stays in the depression 11c, and gas such as a solvent contained therein is directly diffused into the vacuum chamber, and the molten sealing material 16 and the gas vent hole 11b Dissipate into the external vacuum chamber through the gap between Then, the molten sealing material 16 is changed in shape, and thereafter, FIG. 10 and FIG.
As shown in FIG. 1, a part of the gas flows into the gas vent hole 11b, and is hardened in the gas vent hole 11b.
(A point set portion), and the gas vent hole 11b is sealed.

As described above, the molten sealing material 16 stays in the depression for a moment, and during this period, most of the gas diffuses into the external vacuum tank and hardly enters the cavity 13a. Therefore, it is possible to prevent a decrease in the degree of vacuum in the cavity and a decrease in the purity of the reduced-pressure sealed inert gas.

In the above embodiment, the sensing part of the angular velocity sensor is shown as the object to be sealed. However, the present invention can be applied to the object to be sealed of the sensing part such as an acceleration sensor, a pressure gauge, and a variable capacitor. It is.

In the above embodiment, the manufacturing process of the sealing substrate 10 is described first, but this is for convenience, and the manufacturing process of the support substrate 20 may be performed first.

[0036]

According to the first and second aspects of the present invention, an object to be sealed such as a sensing portion is sealed by sealing a gas vent hole over a depression with a sealing material. Since the cavity to be housed is sealed at a predetermined degree of vacuum or under a reduced pressure with an inert gas, vibration of the object to be sealed such as the sensing unit is not suppressed, and the sensitivity is excellent.

According to the third and fourth aspects of the present invention, when the gas vent hole is sealed, the sealing material is formed by a recess provided partially overlapping the gas vent hole. Since the gas is melted and the built-in gas is diffused, the gas generated from the sealing material does not enter the cavity, and the cavity can be sealed at the same pressure and state as the sealing atmosphere.

[Brief description of the drawings]

FIG. 1 shows a method for manufacturing an angular velocity sensor as one embodiment of a method for manufacturing an electronic component of the present invention, in which a photoresist for forming a concave portion is formed on a Pyrex glass substrate as a material of a sealing substrate. Process chart

FIG. 2 is a process diagram of forming a recess by etching a Pyrex glass substrate using the photoresist shown in FIG. 1 as a mask.

3 is a process diagram of forming a gas vent hole in a part of the top surface of the recess formed by the process of FIG. 2;

FIG. 4 Similarly, on the surface of a Pyrex glass substrate,
FIG. 3 is a process diagram of forming a sealing substrate by providing a dent that partially overlaps the gas vent hole formed by the process of FIG. 3.

5 is a partially enlarged plan view of a portion surrounded by a broken line in FIG.

FIG. 6 is a process diagram of forming a photoresist in a planar shape of a sensing unit on an SOI substrate serving as a material of a support substrate.

FIG. 7 is also a process chart for forming a support substrate having a sensing unit by etching a silicon substrate and a sacrificial layer.

8 is a process diagram in which the sealing substrate shown in FIG. 4 is superimposed on the support substrate shown in FIG. 7 and anodic bonding is performed.

FIG. 9 is a process diagram of loading a sealing material into a recess formed in a sealing substrate.

FIG. 10 is a process diagram for sealing the vent hole by heating and melting the sealing material shown in FIG. 9;

FIG. 11 is a plan view of FIG. 10;

FIG. 12 is a plan view of the sensing unit shown in FIG. 7;

FIG. 13 is a partial cross-sectional view showing a conventional electronic component sealing structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oscillator 2, 3 Drive electrode part 2a, 3a, 4a, 5a Movable handle 2b, 3b, 4b, 5b Movable comb electrode 2c, 3c, 4c, 5c Fixed comb electrode 2d, 3d, 4e, 5e Fixed electrode 4 5, detection electrode section 4a, 5a movable pattern 4d, 5d fixed pattern 4f, 5f extraction electrode 6, 7, fixing section 6a, 7a U-shaped support beam 10 sealing substrate 11 Pyrex glass substrate 11a top surface 11b gas vent hole 11c depression Reference Signs List 13 recess 13a cavity 14 SOI substrate 14a upper silicon substrate 14b middle silicon oxide film 14c lower silicon substrate 14d photoresist 15 space 16 sealing material 16a sealing plug 20 support substrate 25 sensing part

Claims (4)

[Claims] 1. A first substrate and a second substrate are bonded to each other to form a cavity between the first substrate and the second substrate. A gas vent hole communicating with the cavity is formed in any one of the substrates, a dent that partially overlaps the gas vent hole is formed on the surface of the substrate, and the sealing material straddles the gas vent hole and the dent. An electronic component in which a vent hole is sealed. 2. A supporting substrate having a sensing portion and a sealing substrate having a recess are joined to form a cavity for accommodating the sensing portion, and a gas vent hole connected to the recess is formed in the sealing substrate. In addition, a dent is formed on the outer surface of the sealing substrate so as to partially overlap with the gas vent hole, and a sealing material is filled in the gas vent hole and the cavity to seal the gas vent hole, An electronic component in which the cavity is sealed. 3. An object to be sealed is disposed on at least one of the first substrate and the second substrate, and a gas vent hole penetrating the substrate is provided in one of the first substrate and the second substrate. Forming a dent that partially overlaps with the gas vent hole on the surface of the substrate, and joining the first substrate and the second substrate in a vacuum or in a reduced pressure inert gas to form the gas vent hole. Forming a communicating cavity, and accommodating the object to be sealed in the cavity, loading a sealing material into the recess, melting the sealing material, and flowing the sealing material out of the recess by the sealing material. A method for manufacturing an electronic component for sealing a gas vent hole. 4. A sensing part is formed in the support substrate, a concave part is formed in the sealing substrate, and a gas vent hole communicating with the concave part is formed in the sealing substrate.
Forming a dent that partially overlaps the gas vent hole on the surface of the sealing substrate, joining the support substrate and the sealing substrate in a vacuum or in a reduced pressure inert gas to form a cavity by the concave portion; And an electron for accommodating the sensing portion in the cavity, loading a sealing material into the depression, melting the sealing material, and sealing the gas vent hole with the sealing material flowing out of the depression. The method of manufacturing the part.