JP2006060564A - Surface acoustic wave device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive surface acoustic wave device with excellent productivity that can surely prevent a sealing resin part from intruding into an interdigital electrode. <P>SOLUTION: Since an air gap is formed by forming a recessed part 1b to an insulation substrate 2 at a position opposed to an interdigital electrode 7 provided to a piezoelectric substrate 6 in the surface acoustic wave device and a one-side (lower side) of the piezoelectric substrate 6 is brought into contact with an upper side of the insulation substrate 2 located near the entire outer circumferential part of the recessed part 1b, the inside of the recessed part 1b can be sealed with the one-side of the piezoelectric substrate 6 and the upper side of the insulation substrate 6 with high accuracy, the intrusion of the sealing resin part 9 to the interdigital electrode 7 can surely be prevented, and application of resin to form a dam part having been required for prior arts is not needed, and the surface acoustic wave device with excellent productivity and of a low cost can be obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface acoustic wave device suitable for use in a wireless device such as a mobile phone.

  FIG. 4 is a cross-sectional view showing the configuration of a conventional surface acoustic wave device. Next, the configuration of the conventional surface acoustic wave device will be described with reference to FIG. A wiring pattern 52 provided over the lower surface and an annular dam portion 53 made of polyimide resin provided in the central portion of the insulating substrate 51 are provided.

  A comb-teeth electrode 55 is provided on the lower surface of the piezoelectric substrate 54 as a lead conductor 55a. The piezoelectric substrate 54 is located outside the dam portion 9 with the comb-teeth electrode 55 located in the annular dam portion 53. The lead portion 55 a is connected to the wiring pattern 52 by conductive bumps 56.

  The bump 56 provides a gap between the comb electrode 55 and the insulating substrate 51 and a sealing resin portion 57 such as an epoxy resin in order to seal the gap where the comb electrode 55 is located from the outside. Is provided between the insulating substrate 51 and the piezoelectric substrate 54, and the dam portion 53 prevents the sealing resin portion 57 from entering the gap. (For example, see Patent Document 1)

  However, in the conventional surface acoustic wave device, it is necessary to provide the dam portion 53 on the insulating substrate 51 in order to prevent the sealing resin portion 57 from entering, which is cumbersome, poor in productivity, and high in cost. In addition, since the dam portion 53 is formed by applying polyimide resin, the height varies, and a gap is formed between the lower surface of the piezoelectric substrate 54 and the top portion of the dam portion 57, and sealing is performed from this gap. A situation occurs in which the stop resin portion 57 reaches the comb electrode 55.

JP-A-5-55303

  In the conventional surface acoustic wave device, it is necessary to provide the dam portion 53 on the insulating substrate 51 in order to prevent the sealing resin portion 57 from entering, which is cumbersome, poor in productivity, and high in cost. Alternatively, since the dam portion 53 is formed by applying a polyimide resin, the height varies, and a gap is formed between the lower surface of the piezoelectric substrate 54 and the top portion of the dam portion 57, and the sealing resin is formed from the gap. There is a problem that a situation occurs in which the portion 57 reaches the comb electrode 55.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a surface acoustic wave device that has good productivity, is inexpensive, and reliably prevents the sealing resin portion from entering the comb-tooth electrode.

  As a first means for solving the above problems, a piezoelectric substrate, a comb electrode having an extraction conductor provided on one surface side of the piezoelectric substrate, and a land portion connected to the extraction conductor are provided on the upper surface. An insulating substrate and a sealing resin portion provided between the piezoelectric substrate and the insulating substrate to seal the comb electrode from the outside, and the comb electrode is disposed on the insulating substrate. The insulating substrate is provided with a concave portion at a position facing the comb electrode, and a gap is formed between the comb electrode and the insulating substrate. The one surface side of the piezoelectric substrate provided with an electrode is in contact with the upper surface of the insulating substrate located near the entire outer peripheral portion of the recess.

  Further, as a second solution, a laminated substrate in which a plurality of the insulating substrates are laminated is provided on at least one of the insulating substrates facing the one surface side of the piezoelectric substrate. The recess is formed by a hole.

  As a third solution, the piezoelectric substrate is provided with a first recess at the edge on the one surface side, and the lead conductor is provided on the inner surface of the first recess, The lead conductor is connected to the land portion at the position of the first recess.

As a fourth solution, the insulating base is provided with a second recessed portion at a position facing the outer peripheral edge of the piezoelectric substrate, and the land portion is formed on the inner surface of the second recessed portion. And the lead conductor is connected to the land at the position of the second recess.
As a fifth solution, a terminal is provided on the lower surface of the insulating substrate, and the land portion and the terminal are connected by a connection conductor provided in the insulating substrate.

A surface acoustic wave device according to the present invention includes a piezoelectric substrate, a comb electrode having an extraction conductor provided on one surface side of the piezoelectric substrate, an insulating substrate having a land portion connected to the extraction conductor on an upper surface, a comb In order to seal the tooth electrode from the outside, it is provided with a sealing resin portion provided between the piezoelectric substrate and the insulating substrate, and the comb electrode is disposed facing the insulating substrate, Is provided with a recess at a position facing the comb electrode, a gap is formed between the comb electrode and the insulating substrate, and one side of the piezoelectric substrate on which the comb electrode is provided is near the entire outer periphery of the recess. It was set as the structure contact | abutted on the surface of the insulating substrate located in this.
That is, at the position facing the comb electrode, a concave portion is provided in the insulating substrate to form a gap portion, and the upper surface of the insulating substrate in which one surface side (lower surface side) of the piezoelectric substrate is located near the entire outer peripheral portion of the concave portion. Since the inside of the recess can be accurately sealed with one surface of the piezoelectric substrate and the upper surface of the insulating substrate, it is possible to reliably prevent the sealing resin portion from entering the comb-teeth electrode, and the conventional resin can be used. The work of applying and forming the dam portion is unnecessary, and a product with good productivity and low cost can be obtained.

  In addition, there is a laminated substrate in which a plurality of insulating substrates are laminated, and a concave portion is formed in this laminated substrate by a hole provided in at least one insulating substrate facing one surface side of the piezoelectric substrate. Can be obtained with good productivity.

  In addition, the piezoelectric substrate is provided with a first recess at the edge on the one surface side, and a lead conductor is provided on the inner surface of the first recess, and the lead conductor is located at the position of the first recess. Since it is connected to the land portion, a connection body made of conductive bumps or the like for connecting the lead conductor and the land portion is located in the first recess, and the connection between the lead conductor and the land portion is ensured by the connection body. It is possible to connect and to obtain a connector without peeling off.

In addition, the insulating base is provided with a second recessed portion at a position facing the outer peripheral edge of the piezoelectric substrate, a land portion is provided on the inner surface of the second recessed portion, and the lead conductor is the second recessed portion. Since the connection body made of conductive bumps or the like for connecting the lead conductor and the land portion is located in the second recess, the connection body is connected between the lead conductor and the land portion. As a result, it is possible to reliably connect and to obtain a connector without peeling off.
Further, in the case where the piezoelectric substrate is provided with the first dent portion, the first dent portion can be formed shallowly, and a decrease in strength of the piezoelectric substrate can be suppressed.

  In addition, since the terminals are provided on the lower surface of the insulating substrate, and the land portion and the terminal are connected by the connection conductor provided in the insulating substrate, the routing between the land portion and the terminal can be reduced, and the size is small and the performance is good. Can be obtained.

  Referring to the drawings of the surface acoustic wave device of the present invention, FIG. 1 is a cross-sectional view of an essential part of a first embodiment of the surface acoustic wave device of the present invention, and FIG. 3 is a plan view showing a state in which the piezoelectric substrate is attached to the multilayer substrate, and FIG. 3 is a cross-sectional view of a principal part according to the second embodiment of the surface acoustic wave device of the invention.

Next, the structure of the first embodiment of the surface acoustic wave device according to the present invention will be described with reference to FIGS. 1 and 2. A laminated substrate 1 is formed by laminating a plurality of insulating substrates 2 made of an alumina substrate or the like. And has a quadrangular recess 1b provided in the center of the upper surface 1a.
The recess 1a is formed by a hole 2a provided in at least one insulating substrate 2 located on the upper surface 1a side, and the bottom of the recess 1a is closed by a second insulating substrate 2 having no hole. It has become.

  In addition, the multilayer substrate 1 includes a plurality of land portions 3 provided on the upper surface 1a so as to surround the recess 1a, a plurality of terminals 4 provided on the lower surface 1c in a state of facing the land portions 3, and a land A connection conductor 5 is provided in the stack so as to connect the portion 3 and the terminal 4.

  The plate-like piezoelectric substrate 6 has a larger area on one surface side (lower surface side) than the recessed portion 1b and a plurality of first recessed portions 6a formed by recessed portions provided on the edge portion on the one surface side. A plurality of comb-teeth electrodes 7 are provided on one surface side of the piezoelectric substrate 6, and an extraction conductor 7 a of the comb-teeth electrode 7 is provided across the inner surface of the first recess 6 a from one surface side. Yes.

Then, when the piezoelectric substrate 6 is placed on the upper surface 1a of the laminated substrate 1 with the comb electrode 7 facing the recess 1b, the one surface side of the piezoelectric substrate 6 is close to the entire outer peripheral portion of the recess 1b. It contacts the upper surface 1a of the laminated substrate 1 positioned.
Then, the comb-shaped electrode 7 is formed with a gap between the concave portion 1 b and the laminated substrate 1, and the concave portion 1 b where the comb-shaped electrode 7 is located is sealed by the contact between the laminated substrate 1 and the piezoelectric substrate 6. It will be in the state.

  When the piezoelectric substrate 6 is placed on the multilayer substrate 1, the first dent portion 6 a is in a state of facing the land portion 3, and the conductive bump located in the first dent portion 6 a. The land portion 3 and the lead conductor 7 a are connected by the connection body 8 made of the like, and the comb-tooth electrode 7 is led out to the terminal 4 through the lead conductor 7 a, the land portion 3, and the connection conductor 5.

  Furthermore, in order to seal dry air or inert gas in the recess 1b and seal the recess 1b in which the comb electrode 7 is located from the outside, a sealing resin portion 9 made of an epoxy resin or the like is formed on the laminated substrate 1. The surface acoustic wave device of the present invention is formed between the piezoelectric substrate 6 and the piezoelectric substrate 6.

  In the above embodiment, the laminated substrate 1 is used. However, the insulating substrate 2 may be used.

  FIG. 3 shows a second embodiment of the surface acoustic wave device according to the present invention. The second embodiment will be described. In the laminated substrate 1, the piezoelectric substrate 6 is opposed to the first recess 6a. The first insulating substrate 2 located on the upper surface 1a side is provided with a hole 2b to form a second recessed portion 1d, and a land portion 3 is provided on the bottom surface of the second recessed portion 1d to provide first and first The land portion 3 and the lead conductor 7a are connected by the connecting body 8 at the positions of the two recessed portions 1d and 6a.

  Other configurations are the same as those of the first embodiment, and the same parts are denoted by the same reference numerals, and the description thereof is omitted here.

  In the second embodiment, the piezoelectric substrate 6 is provided with the first recess 6a. However, the first recess 6a may be eliminated.

The principal part sectional drawing which concerns on 1st Example of the surface acoustic wave apparatus of this invention. The top view which concerns on 1st Example of the surface acoustic wave apparatus of this invention, and shows the state which attached the piezoelectric substrate to the laminated substrate. Sectional drawing of the principal part which concerns on 2nd Example of the surface acoustic wave apparatus of this invention. Sectional drawing which shows the structure of the conventional surface acoustic wave apparatus.

Explanation of symbols

1: Laminated substrate 1a: Upper surface 1b: Recessed portion 1c: Lower surface 1d: Second recessed portion 2: Insulating substrate 2a, 2b: Hole 3: Land portion 4: Terminal 5: Connection conductor 6: Piezoelectric substrate 6a: First recessed portion Part 7: Comb electrode 7a: Lead conductor 8: Connection body 9: Sealing resin part

Claims (5)

A piezoelectric substrate, a comb electrode having an extraction conductor provided on one surface side of the piezoelectric substrate, an insulating substrate having a land portion connected to the extraction conductor on an upper surface, and the comb electrode sealed from the outside In order to do this, it is provided with a sealing resin portion provided between the piezoelectric substrate and the insulating substrate, and the comb electrode is disposed to face the insulating substrate, and the insulating substrate includes: A recess is provided at a position facing the comb electrode, a gap is formed between the comb electrode and the insulating substrate, and the one surface side of the piezoelectric substrate on which the comb electrode is provided is the recess. A surface acoustic wave device, wherein the surface acoustic wave device is in contact with the upper surface of the insulating substrate located in the vicinity of the entire outer peripheral portion. The insulating substrate has a laminated substrate in which a plurality of the insulating substrates are laminated, and the concave portion is formed in the laminated substrate by a hole provided in at least one of the insulating substrates facing the one surface side of the piezoelectric substrate. The surface acoustic wave device according to claim 1. The piezoelectric substrate is provided with a first recess at the edge on the one surface side, and the lead conductor is provided on the inner surface of the first recess, and the lead conductor is the first recess. The surface acoustic wave device according to claim 1, wherein the surface acoustic wave device is connected to the land portion at a position of the portion. The insulating base is provided with a second recess at a position facing the outer peripheral edge of the piezoelectric substrate, the land is provided on the inner surface of the second recess, and the lead conductor is the first conductor. 4. The surface acoustic wave device according to claim 1, wherein the surface acoustic wave device is connected to the land portion at a position of the two recessed portions. 5. 5. The surface according to claim 1, wherein a terminal is provided on a lower surface of the insulating substrate, and the land portion and the terminal are connected by a connection conductor provided in the insulating substrate. Elastic wave device.

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