CN103337588A - Piezoelectric exciter with single-sided lead wire structure, and fabrication method of piezoelectric exciter - Google Patents

Abstract

The invention discloses a piezoelectric actuator with a single-sided lead wire structure, which includes a piezoelectric sheet, electrodes attached to the upper and lower surfaces of the piezoelectric actuator, and electrode leads. The original upper electrode is divided into two asymmetric electrodes, the larger of which is One of them forms the working upper electrode, and the smaller one is connected with the original lower electrode through the silver paste to form the lower electrode of the lead wire. The piezoelectric actuator is located on the lower surface of the vibrating film. The manufacturing method of the piezoelectric actuator disclosed in the present invention uses wet etching to divide the upper electrode into two asymmetric electrodes, bonds the piezoelectric sheet and the silicon sheet together, and thins the piezoelectric sheet by chemical mechanical method. The lower electrode is deposited on the lower surface of the piezoelectric sheet by low-pressure chemical vapor deposition, and the small electrode separated from the upper electrode is connected with the original lower electrode by using silver paste to form the lower electrode of the lead wire, and the lead wire is welded on the upper and lower electrodes. Since the lead wires of the upper and lower electrodes are on the same fixed plane, the electrode short circuit and the lead wire falling off during the periodical vibration of the membrane are avoided, and the reliability of the piezoelectric synthetic jet device is improved.

Description

A piezoelectric actuator with a single-sided lead structure and its manufacturing method

technical field

The invention relates to a piezoelectric actuator with a single-sided lead structure, and also relates to a manufacturing method of the piezoelectric actuator.

Background technique

Piezoelectric excitation is a common driving method in MEMS. Some piezoelectric actuators that appear at present attach the upper and lower electrodes to the upper and lower surfaces of the piezoelectric sheet respectively, and then weld the lead wires to the upper and lower electrodes respectively. The piezoelectric actuator is bonded to the elastic diaphragm, and the periodic voltage signal is applied to the upper electrode and the lower electrode through the lead wire, and the piezoelectric sheet produces periodic longitudinal deformation, which drives the diaphragm to vibrate and completes the drive. However, due to the characteristics of the MEMS processing technology and the device, the lead wire of the lower electrode will contact the upper electrode due to the periodic vibration of the diaphragm, and the upper and lower electrodes will be short-circuited, or the suspended lower electrode lead will fall off due to the periodic vibration of the diaphragm.

Refer to Figure 3. The document "Chinese Patent Piezoelectric Synthetic Jet and Its Manufacturing Method with Patent No. 200710018045.1" discloses a synthetic jet that uses piezoelectric excitation. The synthetic jet uses MEMS etching technology to process a synthetic jet on a silicon substrate. The cavity 7 and the nozzle 1 structure of the device, and then the silicon-based cover plate 2 and the silicon base 3 are assembled by bonding to complete the device processing. This technology has obtained micro-fluidizers in the order of millimeters, but since the lead wires of the piezoelectric actuator are respectively welded to the upper and lower electrodes, when the synthetic jet device is working, the lead wires of the lower electrodes are easily in contact with the upper electrode during the vibration process, resulting in a short circuit. Or the suspended lower electrode leads fall off due to the periodic vibration of the diaphragm.

Contents of the invention

In order to overcome the shortcomings of the existing piezoelectric actuators that the upper and lower electrodes are easily short-circuited and the lead wires of the lower electrodes are easy to fall off, the present invention provides a piezoelectric actuator with a single-sided lead structure and a manufacturing method thereof.

The technical solution adopted in the present invention: a piezoelectric actuator with a single-sided lead structure, which sequentially includes an upper electrode, a piezoelectric sheet 6 and a lower electrode 8; the upper electrode is bonded to the object to be driven, and the upper electrode is divided by the isolation groove It is an independent working upper electrode 4 and a lead lower electrode 10; the lead lower electrode 10 and the lower electrode 8 are conducted through the coated silver paste 11; the upper electrode lead 5 welded on the working upper electrode 4 is the working upper electrode 4 Apply voltage, and apply voltage to the lower electrode 10 through the lower electrode lead 9 welded on the lead lower electrode 10 .

In order to avoid damage to the object to be driven by silver paste coating, ensure that the isolation groove is sealed by the piezoelectric sheet 6 to prevent silver paste from entering.

In order to etch the upper electrode and prevent the lower electrode 8 from contacting the upper electrode when the area of the lower electrode 8 is the same as that of the piezoelectric sheet 6 and cause a short circuit, the outline of the piezoelectric sheet 6 is designed to be included in the upper electrode, and the lower electrode 8 The outline is included in the piezoelectric sheet 6 .

The horizontal section shape of the piezoelectric actuator is square, rectangular or circular.

The material of the upper and lower electrodes is silver, and may also be platinum or other metals.

The electrode lead material is aluminum, and gold, copper or other metals can also be used.

A preparation method of a piezoelectric actuator with a single-sided lead structure, comprising the steps of:

Step 1: Etching an isolation groove on the upper electrode of the piezoelectric sheet 6, and dividing the upper electrode into mutually independent working upper electrodes 4 and lead lower electrodes 10;

Step 2: bonding the upper electrode to the object containing the structure to be driven;

Step 3; Thinning the piezoelectric sheet 6;

Step 4; Deposit the lower electrode 8 on the lower surface of the piezoelectric sheet;

Step 5; patterning the lower electrode 8 and the piezoelectric sheet 6;

Step 6: Connecting the lead lower electrode 10 and the lower electrode 8 through the coated silver paste 11;

Step 7: dividing the repeating unit on the overall device obtained after bonding into small pieces;

Step 8: Weld the upper electrode lead 5 to the working upper electrode 4 , and weld the lower electrode lead 9 to the lead lower electrode 10 .

The beneficial effects of the present invention are: the original upper electrode is divided into independent working upper electrode 4 and lead lower electrode 10 through the isolation groove, wherein the working upper electrode 4 forms a new upper electrode, and the smaller lead lower electrode 10 is formed into a new upper electrode. The silver paste 11 is connected to the lower electrode 8 to form a new lower electrode. Apply voltage to the upper and lower electrodes respectively through the working upper electrode 4 and the lead lower electrode 10, because the working upper electrode 4 and the lead lower electrode 10 are directly attached to the object containing the structure to be driven, so that the lead wires of the upper and lower electrodes are welded on the On the same fixed plane, the lower electrode lead wire is prevented from being directly welded on the suspended lower electrode 8, which solves the problem that the lower electrode lead wire contacts the upper electrode during the periodical vibration of the diaphragm and causes the electrode to short circuit, and at the same time avoids The case where the suspended lower electrode lead comes off due to the periodic vibration of the diaphragm.

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Description of drawings

Fig. 1 is a structural schematic diagram of a piezoelectric actuator with a single-side lead structure installed on a synthetic jet in an embodiment.

FIG. 2 is a top view of FIG. 1 .

Fig. 3 is a structural schematic diagram of a piezoelectric synthetic jet device in the prior art.

In the figure, 1-nozzle, 2-silicon-based cover plate, 3-silicon substrate, 4-working upper electrode, 5-upper electrode lead, 6-piezoelectric sheet, 7-cavity, 8-lower electrode, 9-lower Electrode leads, 10-lead lower electrode, 11-silver paste.

Detailed ways

This embodiment is a synthetic jet whose driving device is a piezoelectric actuator with a single-sided lead structure.

Synthetic jet is one of the important devices in the field of flow control. It adopts piezoelectric, electrostatic or electromagnetic driving methods to make its elastic diaphragm vibrate in suspension, thereby causing periodic changes in the volume of the cavity, thereby dispelling the external gas The cavity is continuously inhaled and discharged through the nozzle, and a synthetic jet is generated without an additional air source to achieve active control of the flow field. Piezoelectric-driven synthetic jet has the characteristics of simple structure, wide operating frequency range, and fast response. It is currently the most researched and most widely used synthetic jet.

Refer to Figure 1 and Figure 2. In this embodiment, the driving device is a synthetic jet device with a piezoelectric actuator with a single-sided lead structure. A cavity 7 is etched on the silicon substrate 3. The upper surface of the silicon substrate 3 is bonded to the silicon-based cover plate 2, and the silicon-based The cover plate 2 has a spout 1 so that the cavity 7 communicates with the outside world; the part of the cavity 7 on the silicon substrate 3 that does not pass through forms a piezoelectric actuator with a single-sided lead structure located below the diaphragm; the piezoelectric actuator with a single-sided lead structure The electric actuator includes an upper electrode, a piezoelectric sheet and a lower electrode in turn; the upper electrode is divided into independent working upper electrodes 4 and lead lower electrodes 10 by the isolation groove, and the upper electrode is bonded to the vibrating diaphragm; the lead lower electrode 10 It conducts with the lower electrode 8 through the coated silver paste 11; the upper electrode lead 5 welded on the upper working electrode 4 is used to apply voltage to the upper working electrode 4, and the lower electrode lead 9 welded on the lower electrode 10 of the lead wire is used as the lead wire The lower electrode 10 is loaded with voltage; the isolation groove is sealed by the piezoelectric sheet 6 to prevent the silver paste from entering.

In this embodiment, a manufacturing method of a piezoelectric actuator with a single-sided lead structure is as follows:

Step 1: Form a mask by photolithography on the upper electrode of the piezoelectric sheet 6, wet-etch an isolation groove, and divide the upper electrode into mutually independent working upper electrodes 4 and lead lower electrodes 10;

Step 2: Bond the upper electrode and the diaphragm of the synthetic jet;

Step 3: Thinning the piezoelectric sheet 6 by chemical mechanical method;

Step 4; Deposit the lower electrode 8 on the lower surface of the piezoelectric sheet;

Step 5: patterning the lower electrode 8 and the piezoelectric sheet 6 by wet etching;

Step 6: Connecting the lead lower electrode 10 and the lower electrode 8 through the coated silver paste 11;

Step 7: Scribing the bonded piezoelectric sheet and silicon sheet to obtain a repeating unit device;

Step 8: Weld the upper electrode lead 5 to the working upper electrode 4 , and weld the lower electrode lead 9 to the lead lower electrode 10 .

Claims (7)

1. the piezoelectric actuator with single face pin configuration comprises top electrode, piezoelectric patches (6) and bottom electrode (8) successively; Top electrode and adhering object to be driven is characterized in that: described top electrode is divided into separate work top electrode (4) and lead-in wire bottom electrode (10) by isolation channel; Lead-in wire bottom electrode (10) and bottom electrode (8) silver slurry (11) conducting by coating; Be work top electrode (4) on-load voltage by the top electrode lead-in wire (5) that is welded on the work top electrode (4), be bottom electrode (10) on-load voltage by the bottom electrode lead-in wire (9) that is welded on the lead-in wire bottom electrode (10).

2. piezoelectric actuator with single face pin configuration as claimed in claim 1, it is characterized in that: the isolation channel on the described top electrode is sealed by piezoelectric patches (6).

3. piezoelectric actuator with single face pin configuration as claimed in claim 1, it is characterized in that: the appearance profile of described piezoelectric patches (6) is contained within the top electrode, and the appearance profile of bottom electrode (8) is contained within the piezoelectric patches (6).

4. piezoelectric actuator with single face pin configuration as claimed in claim 1 is characterized in that: described piezoelectric actuator horizontal cross sectional geometry is square, rectangle or circle.

5. piezoelectric actuator with single face pin configuration as claimed in claim 1 is characterized in that: described upper and lower electrode material is silver, platinum or other metal.

6. piezoelectric actuator with single face pin configuration as claimed in claim 1, it is characterized in that: described contact conductor material is aluminium, gold, copper or other metal.

7. the preparation method as the piezoelectric actuator with single face pin configuration of one of claim 1-6 comprises the steps:

Step 1: the top electrode at piezoelectric patches (6) etches isolation channel, and top electrode is divided into separate work top electrode (4) and lead-in wire bottom electrode (10);

Step 2: with top electrode and the adhering object that comprises structure to be driven together;

Step 3; Attenuate piezoelectric patches (6);

Step 4; Lower surface deposition bottom electrode (8) at piezoelectric patches;

Step 5; Graphical bottom electrode (8) and piezoelectric patches (6);

Step 6; Silver slurry (11) conducting by coating of bottom electrode (10) and bottom electrode 8 will go between;

Step 7; Repetitive on the integral device that obtains after bonding is divided into small pieces;

Step 8: top electrode lead-in wire (5) is welded on the work top electrode (4), bottom electrode lead-in wire (9) is welded on the lead-in wire bottom electrode (10).

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