JPH02180417A - Piezoelectric component - Google Patents

Abstract

PURPOSE:To evade the adverse effect of a resin coating on an oscillating part by providing a cavity layer and a sealing layer respectively on a front cover and a rear cover, arranging the aperture part of the cavity part at a separate position from the front electrode and rear electrode of the oscillating part, and making the sealing layer adhere onto the cavity layer. CONSTITUTION:A cavity layer 171 and a sealing layer 172 are provided on a front cover 17, and a cavity layer 181 and a sealing layer 182 are provided on a rear cover 18 in the same way. Cavity parts 13, 14, 15 and 16 are provided at parts corresponding to oscillating parts 8 and 9 on the cavity layers 171 and 181, and they are made to adhere to a piezoelectric substrate 1. Aperture parts 23 and 24 are provided at the position shifted from front electrodes 81 and 82 and rear electrodes 83 and 93 of the oscillating parts 8 and 9 in the cavity parts 13, 14, 15 and 16. Consequently even when the sealing layer is formed by a resin coating printing means, the practical adverse effect of the insulating resin coating on the oscillating part can be evaded, and the piezoelectric component at high reliability and high productivity can be formed.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a piezoelectric component used, for example, as a filter, a resonator, or an oscillator. The covers are laminated, each of the front cover and the back cover is composed of a cavity layer and a sealing layer, and the cavity layer has a cavity in a portion corresponding to the vibrating part and is brought into close contact with the piezoelectric substrate, The opening of the cavity is provided at a position away from the front electrode and the back electrode of the vibrating part, and the sealing layer is placed tightly on the cavity layer so as to close the opening, thereby sealing the opening of the cavity. We provide piezoelectric components that can easily form a sealing layer and avoid adverse effects on the vibrating part even if the resin paint for forming the sealing layer enters the cavity through the opening. It has been made possible.

<Prior art> FIG. 9 is an exploded perspective view of a conventional piezoelectric component, FIG. 10 is a plan view thereof, FIG. 11 is a front view thereof, and FIG. It is an enlarged sectional view.

In the figure, 1 is a piezoelectric substrate, 2 and 3 are adhesive layers, 4 and 5 are front and back covers, and 6 and 7 are terminals.

A plurality of vibrating parts 8.9 are formed on the piezoelectric substrate 1 at intervals. Each of the vibrating parts 8.9 includes front electrodes (81, 82) and (91, 92) formed on the surface of the piezoelectric substrate 1.
And, on the back side, the obverse Fi (81, 82), (91,
92), and a back electrode 8 provided to face each of the
3.93. Further, capacitive electrodes 10 and 11 are formed on the piezoelectric substrate 1.

The front electrodes (81, 82) and (91, 92) have a gap g
This is a divided electrode divided by ttg2. Front electrode 8
1.91 are respectively connected to extraction electrodes 811 and 911 provided at both corners of one edge of the piezoelectric substrate 1, and the front electrode 82 and the front electrode 92 are connected to the extraction electrode 821, the capacitor electrode 1o, and the extraction electrode 921. are connected to each other through.

The back electrodes 83 and 93 and the capacitive electrode 11 are commonly connected to a ground electrode 12 provided on the back surface of the piezoelectric substrate 1.

The adhesive layer 2.3 is made of thermosetting resin such as epoxy resin. These adhesive layers 2.3 have holes (201, 202) and (301, 302) in the part corresponding to the vibrating part 8.9.
), and when the cover 4.5 is laminated and bonded to both sides of the piezoelectric substrate 1 in the thickness direction via the adhesive layer 2.3, the hole is formed around the vibrating part of the vibrating part 8.9. (201
, 202), (301, 302) hollow part (13,
14) and (15, 16) (see FIG. 12), an energy trapping type piezoelectric component is obtained.

At both corners of the adhesive layer 2, there are cutout portions 2 that expose extraction electrodes 811 and 911 provided at both corners of the piezoelectric substrate 1 during lamination.
03.204 is established. Further, one edge of the adhesive layer 3 is provided with a cutout 303 that exposes the ground electrode 12 provided on the back surface of the piezoelectric substrate 1.

The front cover 4 and the back cover 5 are made of glass, epoxy resin plates, etc., and are bonded together by an adhesive layer 2.3. At both corners of the front cover 4, there are extracted electrodes 811, 911 of the piezoelectric substrate 1 and missing parts 203, 20 of the adhesive layer 2.
Missing portions 401 and 402 corresponding to 4 are provided.

At one end edge of the back cover 5, there is a cutout 3 provided in the adhesive layer 3.
03, a missing portion 51 is provided, and a lead-out voltage 8i52 is provided continuously from the inner surface of this missing portion 51 to the back side.

In the stacked state, the lead electrodes 8 provided at both corners of the piezoelectric substrate 1
11.911 are exposed through the missing parts 203.204 of the adhesive layer 2 and the missing parts 401.402 of the front cover 4, so a conductive layer is applied to the end face including the extraction electrode 811.911 and the terminal 6.7 is exposed. form. As a result, the surface electrode 8
1 extraction electrode 811 and surface electrode 91 extraction electrode 911
is conductively connected to terminal 6.7. Terminal 6.7 is usually
It is formed as a laminated film of vapor deposition and plating.

Further, the surface of the ground electrode 12 is exposed through the cutout part 303 of the adhesive layer 3 into the plane of the cutout part 51 of the back cover 5, and the extraction electrode 52 formed on the inner surface of the ground electrode 12 and the cutout part 51 is exposed.
Connect and fix with solder etc.

The piezoelectric component described above is manufactured through the manufacturing process shown in FIG. For example, if we focus on the vibrating part 8 made up of electrodes 81 to 83, first, as shown in FIG. An adhesive layer 2A made of an epoxy resin adhesive or the like is attached to the electrode 81 so as to surround the electrode Vi81.82.
．． Print so that the thickness is greater than the thickness of 82.

On the other hand, as shown in FIG. 13(b), an adhesive layer 2B made of epoxy adhesive is printed on one side of the cover 4 made of glass, epoxy plate, etc. in the same pattern as the adhesive layer 2A described above. I'll keep it. Then, as shown in FIG. 13(C),
The cover 4 is laminated on one side of the piezoelectric substrate 1 so that the adhesive layer 2A and the adhesive layer 2B completely overlap each other, and are hardened and bonded by means such as thermocompression bonding. The above process is performed on the piezoelectric substrate 1.
By repeating this process on the back side, a piezoelectric component having a cavity 13.15 surrounding the electrodes 81, 82 and 83 is obtained, as shown in FIG. 13(d). 3A is an adhesive layer printed and coated on the piezoelectric substrate 1, and 3B is a next adhesive layer printed and coated on the cover 5. Also on the vibrating part 9 side,
Cavities 14.16 are formed in a similar manner.

<Problems to be Solved by the Invention> The conventional piezoelectric components shown in FIGS. 9 to 12 can be manufactured through the manufacturing process shown in FIG. 13, and thus are relatively easy to manufacture. However, there are the following problems.

(a) In order to reduce the thickness and improve mass productivity, the sealing cover 4.
5 is preferably formed by printing an insulating paint. However, the cavities (13, 14) and (15, 16) are not connected to the electrode (8).
1, 82, 83), (91, 92, 93), so if you try to form the sealing cover 4.5 by resin paint printing, the resin paint will cover the electrodes (81, 82, 93).
83) and (91, 92, 93) and adhere to them. In order to avoid this, as a sealing cover 4.5,
It is necessary to use plate materials such as glass, epoxy resin plates, etc., and to take measures such as gluing them together, resulting in a decrease in mass productivity and an increase in thickness.

(b) When forming the cavities (13, 14) and (15, 16), use adhesive layers (2A, 2B) and (3A, 3B) made of thermosetting adhesive such as epoxy adhesive Since a step of thermocompression-bonding the cover 4.5 onto the substrate 1 is necessary, the hollow portions (13, 14) and (1) are removed in the heat treatment step.
5, 16) may expand, making it impossible to obtain sufficient sealing properties, or the adhesive layer (2A, 2B), (3A, 3
B) vibrating part 8 which must not lose its shape and adhere to it.
This may cause problems such as entering 9.

Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional piezoelectric components, to easily form a sealing layer that seals the opening of a cavity, and to make it possible to easily form a sealing layer that seals the opening of a cavity. To provide a piezoelectric component that can avoid adverse effects on a vibrating part even when paint flows in through an opening.

Means for Solving the Problems> In order to solve the above problems, the present invention provides a flat piezoelectric substrate having a plurality of vibrating parts, a front cover and a back cover laminated on the front and back surfaces of the piezoelectric substrate. , a piezoelectric component having a terminal electrically connected to an electrode of the vibrating part, wherein each vibrating part provided on the piezoelectric substrate has a front electrode and a terminal formed opposite to each other on the front and back surfaces of the piezoelectric substrate. a back electrode is provided, the front electrode is guided to the end of the piezoelectric substrate by a lead electrode formed on the surface of the piezoelectric substrate, and is electrically connected to the terminal; each of the front cover and the back cover includes a cavity layer and a sealing layer, the cavity layer has a cavity in a portion corresponding to the vibrating part and is brought into close contact with the piezoelectric substrate, and the cavity has a surface electrode of the vibrating part. and an opening at a position away from the back electrode, and the sealing layer is made of resin and is tightly adhered onto the cavity layer so as to close the opening.

Each of the front cover and the back cover laminated on the front and back surfaces of the piezoelectric substrate includes a cavity layer and a sealing layer, and the cavity layer has a cavity in a portion corresponding to the vibrating part, and the piezoelectric It is brought into close contact with the substrate, and the cavity has an opening at a position away from the front and back electrodes of the vibrating section. That is, the opening of the cavity is not placed above the front electrode and the back electrode of the vibrating section, but at a distance from them. The sealing layer is brought into close contact with the cavity layer so as to close the above-mentioned opening. With such a structure, even if the sealing layer is formed by resin paint printing, the resin paint can penetrate into the cavity through the opening and furthermore, a certain distance can be secured until it reaches the electrode of the vibrating part.
Substantial adverse effects of the resin paint on the vibrating part can be avoided.

Moreover, since the opening is located away from the front and back electrodes of the vibrating section, it is not limited by the shape of the cavity, making sealing easier.

<Example> FIG. 1 is an exploded perspective view of a piezoelectric component according to the present invention, FIG. 2 is a plan view, FIG. 3 is a front view, FIG. 4 is an enlarged front cross-section, and FIG. It is a sectional view taken along the A1 AI edge line in the figure. In the figure, the same reference numerals as in FIGS. 9 to 12 indicate the same components. 17 is a front cover 18 is a back cover, 19 is an adhesive layer, 20 is a reinforcing layer, and 21 and 22 are metal terminals.

The piezoelectric substrate 1 has a structure similar to that of the conventional example shown in FIG. That is, it has a plurality of vibrating parts 8.9, and each vibrating part 8.9
includes front electrodes (81, 82), (91, 92) and back electrodes (83, 93) formed on the front and back surfaces of the piezoelectric substrate 1 to face each other. Front electrode 81.91
are lead electrodes 811 . formed on the surface of the piezoelectric substrate 1 .
911 to the ends of both corners of the piezoelectric substrate 1, and are also connected to each other via an extraction electrode 821, a capacitor electrode 10, and an extraction electrode 921. Back electrode 83.93
are commonly connected to the ground electrode 12. Ground electrode 12
In this case, the capacitor electrodes 11 provided on both sides of the piezoelectric substrate 1 are also made conductive.

The front cover 17 includes a cavity layer 171 and a sealing layer 172, and the back cover 18 similarly includes a cavity layer 181 and a sealing layer 182.
Contains.

The cavity layer 171.181 has cavity parts (13, 14) and (15, 16) in a portion corresponding to the vibrating part 8.9, and is brought into close contact with the piezoelectric substrate 1.

The hollow parts (13, 14) and (15, 16) are the vibrating part 8.
Openings 23 and 24 are provided at positions away from the front electrodes (81, 82) and back electrodes (83, 93) of No. 9. In the example, the cavities (13, 14), (15, 16) are connected to the front electrodes (81, 82), (91, 92) and the back electrode (83).
, 93), and a part of it is formed into a circular shape so as to surround the narrow passages (131, 141), (151, 161).
) through which it communicates with the openings 23,24.

The edges of the cavity layer 181 and the sealing layer 182 of the back cover 18 are provided with cutout portions 26 and 27 that expose the ground electrode 12 provided on the back surface of the piezoelectric substrate 1. 25 is front cover 17
This is a missing part provided on the edge of one.

The sealing layers 172 and 182 are made of insulating resin, and the openings 23
．． 24, and are brought into close contact with the cavity layers 171 and 181 so as to close the cavity layers 171 and 181. It is desirable that the sealing layers 172 and 182 be formed of ultraviolet curing resin.

Cavity layer 171 and sealing layer 172 that constitute front cover 17
is a lead electrode 8 provided at a corner of the surface of the piezoelectric substrate 1.
11. The part corresponding to the end of 911 is the notch part 28-3
1, and the terminals 21 and 22 are connected to these notches 2.
It is electrically connected to lead electrodes 811 and 911 through terminals 8 to 31.

The terminals 21 , 22 are formed using a thin metal plate having spring properties, and have electrode contact parts 211 , 221 that contact the lead electrodes 811 , 911 through the notches 28 to 31 , and front contacts that contact the front cover 17 . Cover contact part 212.22
It has 2.

213 and 223 are contact portions that contact the reinforcing layer 20 on the back side.

The electrode contact portions 211.221 are connected to the front cover contact portions 212.221.
222 are spring pieces separated by slits 214, 224. The front cover 17 has a lead electrode 8
11.911, and a step corresponding to the thickness of the front cover 17 is formed between the lead electrode 811.911 and the surface of the front cover 17.

The height of the electrode contact portions 211.221 is the same as the lead electrode 811.221.
911, and the front cover contact part 2
12.222 is at a height that makes contact with the surface of the front cover 17. Therefore, the above-mentioned level difference can be absorbed.

The reinforcing layer 20 is made of glass, epoxy resin, etc., and the adhesive layer 1
9 is bonded to the surface of the sealing layer 182 constituting the back cover 18 . The reinforcing layer 20 is provided only on the back cover 18 side and not on the front cover 17 side. Therefore, it becomes thin. A hollow layer 171 of the front cover 17 and a hollow layer 18 of the back cover 18 are provided at one end edge of the reinforcing layer 20.
1 and the cutout portion 26.2 provided at the edge of the sealing layer 182
7, a missing portion 32 is provided, and this missing portion 3
An extraction electrode 33 is provided continuously from the inner surface to the back surface of 2.

The piezoelectric component described above can be manufactured, for example, by the manufacturing process shown in FIG. First, as shown in FIG. 8(a), a resist 34 is printed on the surfaces of the front electrodes (81, 82) and (91, 92) according to the required thickness and area of the cavity.
dry.

Next, as shown in FIG. 8(b), a resin paint is printed on the surface of the piezoelectric substrate 1 so as to cover the resist 34, thereby forming a cavity layer 171. The cavity layer 171 has surface electrodes (81,
82), (91, 92) are removed from the opening 23.2.
The pattern is such that 4 occurs.

Next, after drying the cavity layer 171, the resist 34 inside is extracted through the openings 23 and 24, as shown in the eighth section (C). This forms cavities 13.14. When the cavity layer 171 is formed of an ultraviolet curable resin, it can be rapidly cured by ultraviolet irradiation.

Next, as shown in FIG. 8(d), on the cavity layer 171,
A similar resin paint is applied thinly to form a sealing layer 172. Here, from the opening 23, the electrode (81
, 82) and (91, 92), it is possible to prevent the insulating resin paint from flowing into and adhering to the vibrating portion 8.9. Moreover, at the stage of applying the sealing layer 172, the cavity layer 171 has already been hardened, and the cavity 13.
Further, when the sealing layer 172 is formed of an ultraviolet curable resin, the heat treatment process can be omitted and air expansion within the cavity 13 and 14 can be avoided.

The above-mentioned process is repeated on the back side of the piezoelectric substrate 1 to form a back cover 18 having the same structure, and then, as shown in FIG. 8(e), the back cover 18 is reinforced with adhesive IW19. This is completed by gluing layer 20.

The manufacturing process described above is not performed for each individual piezoelectric component, but is performed as a process for simultaneously forming a large number of piezoelectric components on a wafer.

Sealing layers 172 and 182 of front cover 17 and back cover 18
When the opening 23. is formed by printing resin paint, the opening 23.
As a means to more reliably prevent the resin paint that has flowed into the cavities 13 to 16 from the openings 23 and 24 from entering the vibrating part 8.9, as shown in FIGS. It is effective to provide barrier parts 35 to 38 to prevent resin inflow in the middle of the path leading to the electrodes 81 to 83 and 91 to 93 in the part 8.9. Such barrier parts 35 to 38
can be easily formed by providing an uncoated portion in a part of the resist pattern (FIG. 8, 34). Further, the barrier portions 35 to 38 may have any pattern that prevents resin inflow, and are not limited to the illustrated shape, and may be a convex portion or a concave portion instead of a columnar shape.

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

(A) Each of the front cover and back cover laminated on the front and back surfaces of the piezoelectric substrate includes a cavity layer and a sealing layer, and the cavity layer has a cavity in a portion corresponding to the vibrating part and is piezoelectric. Since the cavity is in close contact with the substrate and has an opening at a position away from the front and back electrodes of the vibrating part, even if the sealing layer is formed by resin paint printing means, the vibrating part It is possible to provide a piezoelectric component that is highly reliable and can be mass-produced by avoiding the substantial adverse effects of the insulating resin paint on the material.

(B) Since the opening is formed at a position away from the front and back electrodes of the vibrating section, it is not limited by the shape of the cavity and is suitable for extracting resist and preventing resin inflow during the manufacturing process. It is possible to provide a piezoelectric component that can be set at a suitable position and whose cavity can be easily formed and sealed.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a piezoelectric component according to the present invention, FIG. 2 is a plan view, FIG. 3 is the same (front view, FIG. 4 is an enlarged front cross-section, and FIG. - A cross-sectional view on the Al line, FIG. 6 is an enlarged front cross-section of yet another embodiment of the piezoelectric component according to the present invention, and FIG. 7 is an A2 of FIG. 6.
FIG. 8 is a cross-sectional view taken along line A2, FIG. 8 is a diagram showing an example of a manufacturing method for manufacturing a piezoelectric component according to the present invention, FIG. 9 is an exploded perspective view of a conventional piezoelectric component, and FIG. 10 is a plan view thereof, and FIG. Figure 11 is the same front view, and Figure 12 is Figure 10 B+B.
An enlarged cross-sectional view on +JJl, FIG. 13, is a diagram also showing the manufacturing method. 1... Piezoelectric substrate 8.9... Vibrating part 81.8
2.91.92...Front electrode 83.93...Back electrode 17...Front cover 171...Cavity layer 172.
... Sealing layer 18 ... Back cover 181 ... Cavity layer 182 ...
...Sealing layer 21.22...Terminal 23.24...Opening 27 Fig. 3 Fig. 4 Fig. 8 +5 (+6) Fig. 10 Atsushi Fig. 12 +5 (+6)

Claims (4)

[Claims] (1) A piezoelectric component having a flat piezoelectric substrate having a plurality of vibrating parts, a front cover and a back cover laminated on the front and back surfaces of the piezoelectric substrate, and a terminal electrically connected to an electrode of the vibrating part. Each vibrating section provided on the piezoelectric substrate includes a front electrode and a back electrode formed to face each other on the front and back surfaces of the piezoelectric substrate, and the front electrode is arranged on the front surface of the piezoelectric substrate. lead electrodes formed on the piezoelectric substrate are guided to the ends of the piezoelectric substrate and electrically connected to the terminals; each of the front cover and the back cover includes a cavity layer and a sealing layer; A hollow portion is provided in a portion corresponding to the vibrating portion and is brought into close contact with the piezoelectric substrate, and the hollow portion has an opening portion at a position away from the front electrode and the back electrode of the vibrating portion. A piezoelectric component characterized in that the sealing layer is made of resin and is brought into close contact with the cavity layer so as to close the opening. (2) The front cover has a notch in a portion corresponding to the end of the lead electrode, and the terminal is electrically connected to the lead electrode through the notch. A piezoelectric component according to scope 1. (3) The terminal is a metal member having an electrode contact part that contacts the lead electrode through the notch, and a front cover contact part and a back cover contact part that contact the front cover and the back cover, and 3. The piezoelectric component according to claim 2, wherein the electrode contact portion is a spring piece separated from the front cover contact portion by a slit. (4) According to claim 1, 2, or 3, the cavity has a barrier part in the middle of a path from the opening to the electrode of the vibrating part. Piezoelectric components listed.