JPS63175512A - Piezoelectric component and its manufacture - Google Patents

Abstract

PURPOSE:To attain simple and sure adhesion with high accuracy by using an adhesives including an optical curing group and a thermosetting group and having a pattern of a part of which corresponding to a cavity is removed and adhering a cover to both sides of a piezoelectric substrate. CONSTITUTION:Since adhesives 12, 13 include the optical curing group and the thermosetting group, the optical curing reaction of the optical curing group is utilized and the pattern of cavities 8, 9 is formed by photo etching, the thermosetting reaction of the thermosetting group is utilized to adhere and fix the covers 6, 7. Thus, the pattern accuracy of the cavities 8, 9 is high and the adhesion of the adhesives to the cavities 8, 9 and the electrodes 2, 3 is eliminated and the piezoelectric component adhering the covers 6, 7 simply and surely is offered.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an energy trapping type piezoelectric component, in which vibration cavities are created around electrodes provided on both sides of the piezoelectric substrate. By bonding the cover using an adhesive containing a photocurable group and a thermosetting group, the pattern of the cavity, which is important in this type of piezoelectric component, can be created using a photo-developing method. It can be formed with high precision, and the cover can be easily and reliably bonded by means such as thermocompression bonding.

In conventional energy trapping type piezoelectric components, only the electrode section provided in the center of the piezoelectric substrate vibrates, so it is necessary to form a vibration cavity around the electrode section so as not to inhibit this vibration. be. Known documents for this purpose include, for example, Japanese Unexamined Patent Publication No. 110217/1983. FIG. 4 shows this conventional technique, in which a circular vibration electrode 2.3 is formed approximately at the center of both sides of the piezoelectric substrate 1 in the thickness direction, and both sides of the piezoelectric substrate 1 are coated with epoxy resin or the like. It has a structure in which an insulating cover 6.7 is bonded using a thermosetting adhesive 4.5. The adhesive 4.5 is thicker than the electrode 2.3 and separates from the electrode 2.3 so that a vibration cavity 8.9 is created around the electrode 2.3. The insulating cover 6.7 is laminated on the thus applied adhesive 4.5, and is bonded under heat and pressure. Reference numeral 21.31 is an extraction electrode of the electrode 2, and 10.11 is an end electrode that conducts the extraction electrode 8i21.31.

Problems to be Solved by the Invention However, the above-mentioned conventional piezoelectric components have the following problems.

(B) When applying the thermosetting adhesive 4.5, the space in which the cavity 8.9 is to be formed may be affected by misalignment of the printing position or the fluidity of the adhesive (based on the base). Adhesive 4.
In the worst case, the adhesive 4.5 will adhere to the electrode 2.3.
In some cases, the adhesive 4.5 adheres to the adhesive 4.5, or the cavity 8.9 is filled with the adhesive 4.5, making it impossible to obtain the desired characteristics.

(b) In the hot press process for heat-pressing the cover 6.7, the cavity 8.5 is created by fluidization of the adhesive 4.5.
It is difficult to select the adhesive 4.5, control the heating temperature pattern, and control the applied pressure.

(c) Since it is necessary to avoid soaking of the cavity 8.9,
Pot press pressure cannot be increased. For this reason, it is difficult to form the cavity 8.9 with high airtightness.

Means for Solving the Problems In order to solve the above-mentioned conventional problems, a piezoelectric component according to the present invention is provided with electrodes facing each other on both sides of a piezoelectric substrate, and electrodes arranged around the electrodes on both sides of the piezoelectric substrate. In a piezoelectric component having a cover adhered so as to form a vibration cavity in the piezoelectric component, the cover is bonded with an adhesive having a pattern including a photocurable group and a thermosetting group and in which a portion corresponding to the cavity is removed. It is characterized in that it is bonded to both sides of the piezoelectric substrate.

Further, in the method for manufacturing a piezoelectric component according to the present invention, after applying an adhesive containing a photocuring group and a thermosetting group to substantially the entire surface of a piezoelectric substrate on which vibration electrodes are formed at opposite positions on both sides, a photocuring agent is applied. forming an adhesive pattern in which the adhesive on the electrode is removed in an area larger than the area of the electrode by etching;
Then, on the adhesive left on both sides of the piezoelectric substrate,
The feature is that the covers are laminated and bonded by thermocompression.

When the cover is bonded using an adhesive containing a photocuring group and a thermosetting group, the pattern of the cavity, which is important in this type of piezoelectric component, can be created by photo-development using the photocuring group contained in the adhesive. It can be formed with high precision using the method. Furthermore, the cover can be easily and reliably bonded to the adhesive patterned with high precision in this manner by thermocompression bonding or the like by utilizing its thermosetting group.

In addition, in the method for manufacturing a piezoelectric component according to the present invention, after applying an adhesive containing a photocuring group and a thermosetting group to substantially the entire surface of the piezoelectric substrate, the photocuring reaction of the photocuring group is utilized by photoetching. Then, the cavity pattern is fixed, and then a cover is laminated thereon and bonded by thermocompression using the thermosetting group of the adhesive that has been temporarily cured by a photocuring reaction.

Therefore, with the manufacturing method according to the present invention, there is no possibility of problems such as adhesive adhering to the vibration cavity or the electrodes. Furthermore, since the cover is heat-pressed to the adhesive which has been temporarily cured by a photo-curing reaction, collapse of the cavity is less likely to occur during hot pressing. Therefore, it becomes easy to manage the heating temperature pattern and the applied pressure. Furthermore, since the cavity is less likely to collapse, the hot press pressure can be increased to form a cavity with high airtightness.

Embodiment FIG. 1 is a partially cutaway view of a piezoelectric component according to the present invention, and FIG. 2 is a front cross-sectional view of the piezoelectric component according to the present invention. While forming a circular vibration electric field fi2.3, a piezoelectric substrate 1
Adhesive 12.1 containing a photocurable group and a thermosetting group on both sides of the
It has a structure in which the insulating covers 6 and 7 are adhered using 3. The adhesive 12.13 is thicker than the electrode 2.3 and formed at a distance from the electrode 2.3 so as to create a vibration cavity 8.9 around the electrode 2.3. be. 2
1.31 is an extraction electrode of the electrode 2, and 10.11 is an end electrode that conducts the extraction electrode 21.31.

Since the adhesive 12.13 contains a photocuring group and a thermosetting group,
After the pattern of the cavity 8.9 is formed by photoetching using the photocuring reaction of the photocuring group, the cover 6.7 can be adhesively fixed using the thermosetting reaction of the thermosetting group. Therefore, it is possible to provide a piezoelectric component in which the pattern accuracy of the cavity 8.9 is high, there is no adhesive adhesion to the cavity 8.9 and the electrode 2.3, and the cover 6.7 can be easily and reliably adhered. .

FIG. 3 is a diagram showing a method of manufacturing a piezoelectric component according to the present invention using a photodevelopment method. First, as shown in Figure 3(a),
Electrodes 2.3 and their lead-out electrodes 21.31 are formed in opposing positions on both sides of the piezoelectric substrate 1 formed into a flat plate shape.

Next, as shown in FIG. 3(b), adhesives 12 and 13 containing a photocuring group and a thermosetting group are applied to substantially the entire surface of the piezoelectric substrate 1. Examples of adhesives 12.13 include:

CH2-CH~CH2-〇-〇-CI2~CD-1:H
2 As shown in the chemical formula above, the adhesive used in the present invention has an acrylic group CH2-CI+ that acts as a photocurable group at one end group, and an epoxy group cH- that acts as a thermosetting group at the other end group. Like co2, both end groups are different. This composition contains an ultraviolet curing agent and an epoxy group C.
A curing agent that opens H-co2 (for example, imidazole, acid anhydride, aromatic amine, etc.) is used in combination.

Next, as shown in FIG. 3C, a photomask 14.15 is applied onto the adhesive 12.13 on the electrode 2.3 in an area larger than the area of the electrode 2.3.

Next, it is irradiated with ultraviolet light. Adhesive 12.1 in the area (a) without photomask 14.15 is removed by ultraviolet irradiation.
The acrylic group CH2-CH contained in No. 3 is cured to become a temporarily cured product that is insoluble in organic solvents and dilute alkaline solutions.

The central portion (b) of the photomask 14 and 15 does not undergo photocuring and is therefore soluble in organic solvents and dilute alkaline solutions.

Next, the photomask 14.15 is removed, and the adhesive 12.13 in the central portion (b) below the photomask 14.15 is removed using an etching solution. As the treatment liquid, an organic solvent or a dilute alkaline solution can be used. The adhesive 12.13 in the center area (b) where the photomask 14.15 was located is soluble in the above-mentioned processing solution, but the adhesive 12.13 in the area (a) where the photomask 14.15 was not.
Since the adhesive does not melt, a piezoelectric component having an adhesive pattern with a fixed cavity pattern can be obtained as shown in FIG. 3(d).

Next, as shown in FIG. 3(e), the cover 6.7 is laminated and bonded under heat and pressure using a pot press to achieve adhesion and complete curing by the residual epoxy group CH-CH2. Cover 6.7 is fixed with adhesive. Since the adhesive 12.13 to which the cover 6.7 is heat-pressed is temporarily cured by a photocuring reaction, the cavity 8.9 is less likely to collapse during hot pressing. Therefore, it becomes easy to manage the heating temperature pattern and the applied pressure.

Furthermore, since the cavity 8.9 is less likely to collapse, the hot press pressure can be increased to form the cavity 8.9 with high airtightness.

Thereafter, by applying end electrodes, the electronic component according to the invention can be obtained.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(a) The pattern of the cavity can be formed with high precision by photo-developing, and the cover can be easily and reliably bonded by means such as thermocompression bonding.

(b) There is no possibility of problems such as adhesion of adhesive to cavities or electrodes, and an energy trapping type piezoelectric component with stable characteristics can be easily obtained.

(e) The cavity is less likely to collapse when the cover is hot-pressed, making it easier to manage the heating temperature pattern and the applied pressure.

(d) Since the cavity is less likely to collapse, the hot press pressure can be increased to form a cavity with high airtightness.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway view of a piezoelectric component according to the present invention, FIG. 2 is a front cross-sectional view, FIGS. The figure is a cross-sectional view of a conventional piezoelectric component. 1... Piezoelectric substrate 2.3... Electrode 6.7...
・Cover 8.9...Cavity part 12.13...Adhesive Figure 1 Figure 2 Figure 3

Claims (3)

[Claims] (1) A piezoelectric component in which electrodes facing each other are provided on both sides of a piezoelectric substrate, and covers are bonded to both sides of the piezoelectric substrate so that a vibration cavity is created around the electrodes,
The piezoelectric component is characterized in that the cover is adhered to both sides of the piezoelectric substrate with an adhesive having a pattern including a photocurable group and a thermosetting group and in which a portion corresponding to the cavity is removed. (2) The piezoelectric component according to claim 1, wherein the piezoelectric substrate has end electrodes that are electrically connected to the electrodes at opposite ends thereof. (3) After applying an adhesive containing a photocurable group and a thermosetting group to almost the entire surface of a piezoelectric substrate on which vibration electrodes are formed at opposing positions on both sides, the adhesive on the electrodes is removed by photoetching. A piezoelectric component characterized in that a removed adhesive pattern is formed in an area larger than the area of the electrode, and then a cover is laminated on the adhesive left on both sides of the piezoelectric substrate and bonded by thermocompression. manufacturing method.