JPH102741A - Manufacture of piezoelectric transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the characteristics by promoting free vibration by forming a solder bump at the opening part of a piezoelectric element, wherein the opening of a solder resist is located, and coupling a supporting part, which is to become a supporting place at the node of the vibration of the piezoelectric element, to the supporting electrode of a supporting substrate. SOLUTION: A solder resist 3, which is formed on one main surface of an electrode 2 of a piezoelectric substrate 1, has an opening 3a at the supporting part of a divided each piezoelectric element 1a corresponding to the node of the bending vibration. A solder bump 4 is formed at the opening position of the electrode 2 located at the opening 3a. The piezoelectric substrate 1, wherein the solder bump 4 is formed, is cut and divided intol a plurality of the piezoelectric elements 1a. The node part of the piezoelectric element 1a is limitedly supported by the supporting body, which is formed by the fusion, solidification and deformation of the solder part bump 4. This supporting body imparts the strength for supporting the piezoelectric element 1a and the electric connection to a supporting electrode 5a. From the remaining electrode 2 of the piezoelectric element 1a, a lead wire is guided out at the node point of the vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a piezoelectric vibrator used for a vibrating gyroscope, an oscillator, a resonator, a filter, and the like.

[0002]

2. Description of the Related Art A conventional method for manufacturing a piezoelectric vibrator will be described with reference to FIGS. First, in FIG. 13, reference numeral 50 denotes a rectangular parallelepiped piezoelectric element, and electrodes 51 are formed on both opposing surfaces thereof. The piezoelectric element 50 has various vibration modes. Among them, the node 52 in the bending vibration mode is a portion indicated by a broken line. On the other hand, 53 is a support substrate. When attaching the piezoelectric element 50 to the support substrate 53, it is necessary to support the piezoelectric element 50 at the node 52 of the piezoelectric element 50 so as not to suppress the bending vibration of the piezoelectric element 50.

Conventionally, as a method of manufacturing the support, a conductive or solder paste 54 is applied to the node 52 of the piezoelectric element 50 by a dispenser or a printing machine, and the piezoelectric element 50 coated with the paste 54 is As shown in FIG. 14, the paste 54 is placed on the support substrate 53, and the paste 54 contacts the support electrodes 53 a formed on the support substrate 53. Then, an appropriate pressing force is applied to the piezoelectric element 50 to cure or melt-solidify the paste 54, thereby fixing the piezoelectric element 50 to the support substrate 53.

[0004]

However, in the conventional method for manufacturing a piezoelectric vibrator, since the paste 54 is applied by a dispenser or a printing machine, the viscosity change of the paste 54 or the work Due to a change in the environment, the application amount was varied, and the application area was changed. For this reason, the piezoelectric element 50 is not supported at an appropriate portion of the node 52, and the characteristics of the piezoelectric vibrator vary. Therefore, in order to keep the applied amount constant, it is necessary to control the work environment such as the viscosity and temperature of the paste 54 to a constant level, which has led to a reduction in work efficiency.

[0005] When the paste 55 is melted, as shown in FIG.
As shown in FIG. 5, the piezoelectric element 50 is
As shown in FIG. 16, it is fixed by being inclined in the longitudinal direction, or it is fixed by being inclined in the short direction as shown in FIG.
As shown in (1), there is a problem that it is rotated and fixed in the horizontal direction. In particular, in the case of a piezoelectric element 50 for a vibrating gyroscope, the fixing angle and inclination accuracy of the piezoelectric element 50 with respect to the support substrate 53 are important, and expensive equipment is required to accurately fix the piezoelectric element 50 to the support substrate 53. Was required.

Accordingly, the present invention provides a method for manufacturing a piezoelectric vibrator in which free vibration is promoted and characteristics are stabilized by locally and highly accurately supporting a piezoelectric element on a supporting substrate at a node of the vibration. The purpose is to do.

[0007]

The present invention is characterized by the following means for achieving the above object. That is, a first aspect of the present invention provides a step of forming a solder resist having an opening in a support portion of the piezoelectric element on one main surface of a piezoelectric element on which an electrode is formed, and positioning the solder resist in the opening of the solder resist. Forming a solder bump at the opening of the electrode, attaching the piezoelectric element to the support substrate by bonding the solder bump to the support electrode of the support substrate, and removing the solder resist. .

According to the present invention, a solder resist having an opening at a portion serving as a node of vibration of a piezoelectric element is formed, and a solder bump is formed at an opening portion of the piezoelectric element at which the opening of the solder resist is located, so that the vibration of the piezoelectric element Since the supporting portion serving as a supporting point at the node is coupled to the supporting electrode of the supporting substrate, when the solder pump is melted, the melting area is limited to the size of the opening, and does not expand further, and the piezoelectric element The piezoelectric element can be fixed to the support substrate in a limited manner at an appropriate portion of the vibration node.

Further, in the present invention, the solder resist is interposed between the support substrate and the piezoelectric element, the piezoelectric element is maintained substantially horizontal with respect to the support substrate, and the piezoelectric element is moved in the longitudinal direction or the transverse direction. It does not tilt or rotate horizontally. A second invention is a step of forming a solder resist having a plurality of openings arranged at equal intervals on one main surface of a piezoelectric substrate on which electrodes are formed, and forming the piezoelectric substrate on the one side of the solder resist. Dividing the solder resist into a plurality of piezoelectric elements having openings, forming solder bumps at the openings of the electrodes located at the openings of the solder resist in the piezoelectric elements, and forming the solder bumps on the support electrodes of the support substrate. And a step of attaching the piezoelectric element to the support substrate and a step of removing the solder resist.

The present invention provides, in addition to the function of the first invention, a method of forming a solder resist on a piezoelectric substrate at a time, and then dividing the piezoelectric substrate into individual piezoelectric elements.
Solder bumps can be formed for each individual piezoelectric element.

According to a third aspect of the present invention, a step of forming a solder resist having a plurality of openings on one main surface of a piezoelectric substrate on which electrodes are formed, and a step of forming a solder resist on the piezoelectric substrate at the openings of the solder resist. Forming a solder bump at an opening of the electrode located; dividing the piezoelectric substrate into a plurality of piezoelectric elements having the solder bump; and coupling the solder bump of the piezoelectric element to a support electrode of a support substrate. Accordingly, the method includes a step of attaching the piezoelectric element to the support substrate and a step of removing the solder resist.

The present invention provides, in addition to the function of the first invention, a method of forming a solder resist having a plurality of openings in a piezoelectric substrate, and forming solder bumps in the openings, and then forming the piezoelectric substrate. Since each piezoelectric element is divided, a solder resist and a solder bump can be collectively formed on the piezoelectric substrate.

According to a fourth aspect of the present invention, a step of forming a solder resist having at least one opening on one main surface of a support substrate on which electrodes are formed, and a step of forming a solder resist on the support substrate at the opening of the solder resist. Forming a solder bump in the opening of the electrode located, attaching the piezoelectric element to the support substrate by bonding a supporting portion of the piezoelectric element to the solder bump, and removing the solder resist. Become.

According to the present invention, contrary to the first invention, a solder resist having an opening is formed on a supporting substrate, a solder bump is formed in the opening, and a supporting portion for a node of a piezoelectric element is formed on the solder bump. Join. That is, the first invention forms a solder resist and a solder bump on a piezoelectric substrate, whereas the present invention forms a solder resist and a solder bump on a support substrate. However, even with this difference, it has substantially the same operation as the operation described in the first invention.

According to a fifth aspect of the present invention, a step of forming a solder resist having a plurality of openings on one main surface of a piezoelectric substrate on which electrodes are formed, and a step of forming a solder resist on the piezoelectric substrate at the openings of the solder resist. Forming a solder bump in an opening portion of the electrode located; and bonding the solder bump of the piezoelectric substrate to the supporting electrode of the insulating substrate on which a plurality of supporting electrodes are formed, thereby forming the insulating substrate on the piezoelectric substrate. Attaching to, and dividing the combined body of the piezoelectric substrate and the insulating substrate into a plurality of piezoelectric vibrators,
Removing the solder resist.

The present invention provides, in addition to the function of the first invention, in particular, after forming a solder resist and a solder bump on a piezoelectric substrate, without dividing the piezoelectric substrate into piezoelectric elements,
The piezoelectric substrate is directly bonded to the insulating substrate via solder bumps, and then divided into a plurality of piezoelectric vibrators. Therefore, the formation of the solder resist, the formation of the solder bumps, the bonding of the solder bumps, and the dicing to the chip (piezoelectric vibrator) can be collectively processed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a method for manufacturing a piezoelectric vibrator according to the present invention will be described below with reference to FIGS. First, in FIG. 1, reference numeral 1 denotes a piezoelectric substrate, which is made of, for example, a piezoelectric material such as piezoelectric ceramics, lithium niobate, lithium tantalate, and quartz. Electrodes 2 are formed on both surfaces of the piezoelectric substrate 1. And
The piezoelectric substrate 1 is divided into a plurality of piezoelectric elements 1a in a later step as shown by a broken line.

In FIG. 2, a solder resist 3 is formed on one main surface of the electrode 2 of the piezoelectric substrate 1. The solder resist 3 has an opening 3a at a support site corresponding to a node of bending vibration of each of the divided piezoelectric elements 1a. The opening 3a is formed by, for example, a resist mask or photo etching. The shape of the opening 3a may be any shape such as a circle, an ellipse, a rectangle, and a band. In the piezoelectric vibrator for a vibrating gyroscope according to the present embodiment, the diameter (width) is, for example, 0.1. ~
0.2 mm. And the diameter (width) of this opening 3a
Limits the range in which the solder bumps described later melt and spread.

In FIG. 3 and, more specifically, in FIG. 4, the opening 2 of the electrode 2 located at the opening 3a of the solder resist 3 is shown.
For example, a solder bump 4 having a height about twice the thickness of the solder resist 3 is formed on a. The solder bump 4 is formed slightly smaller and higher than the size of the opening 3 a of the solder resist 3. Specifically, the height of the solder bump is 100 μm with respect to the thickness of the solder resist of 20 to 50 μm. The solder bumps 4 are formed by a conventionally known means such as a wire bonding method, a solder ball method, a printing method, and a dipping method.
In this case, the volume of the solder bump 4 is formed to be equal to or slightly smaller than the volume of the opening 3a. As described above, the piezoelectric substrate 1 on which the solder bumps 4 are formed is cut and divided into a plurality of piezoelectric elements 1a by, for example, a dicing machine, as indicated by broken lines. In FIG. 5, the divided piezoelectric elements 1a are arranged with the solder bumps 4 facing the support substrate 5 (downward). The support substrate 5 is made of, for example, a multilayer substrate, and a support electrode 5a is provided on the surface thereof. Preferably, a solder wetting prevention film is provided on the surface of the multilayer substrate except for the support electrode 5a, and is flush with the support electrode. The support substrate 5 is prepared for each piezoelectric element 1a.

In FIG. 6, a piezoelectric element 1 is placed on a support substrate 5.
is placed, and the solder bumps 4 are brought into contact with the support electrodes 5 a provided on the support substrate 5 at positions corresponding to the positions of the solder bumps 4. Thereafter, the surface of the solder resist 3 is brought into contact with the surface of the support substrate 5 while melting the solder bumps 4 with an infrared furnace, an oven or the like. As a result, the solder bump 4 is deformed under the influence of the shape of the opening 3a of the solder resist 3, and is solidified as the support 4a. When the solder bumps 4 are melted and solidified, the piezoelectric elements 1a are automatically aligned and fixed at appropriate positions on the support substrate 5 by the alignment action. The supporting electrode 5a may have any shape and size as long as it is not extremely small with respect to the diameter of the solder bump 4.
The support electrode 5a also serves as an extraction electrode of the piezoelectric element 1a, and is connected to a wiring pattern provided on the support substrate 5.

In FIG. 7, the piezoelectric element 1a fixed to the support substrate 5 is immersed in a resist stripping solvent to strip the solder resist 3 and to be washed. The piezoelectric element 1a is
The node portion is limitedly supported by the support 4a in which the solder bump 4 is melted and solidified and deformed.
“a” provides strength for supporting the piezoelectric element 1 a and electrical connection to the support electrode 5 a of the support substrate 5. Then, a lead wire r is led out from the remaining electrode 2 of the piezoelectric element 1a at a node point of vibration, and a piezoelectric vibrator is manufactured.

Next, a second embodiment of the present invention will be described with reference to FIGS. This embodiment is different from the first embodiment in that the solder resist and the solder bump are formed on the piezoelectric substrate (piezoelectric element) side, whereas the insulating substrate (support substrate) is used.
The difference from the first embodiment lies in the formation on the side.

First, in FIG. 8, reference numeral 6 denotes an insulating substrate made of a resin substrate, a ceramic substrate, or the like. An electrode 7 is formed on the entire surface of one main surface of the insulating substrate 6. Then, the solder resist 3 is formed on the electrode 7. The solder resist 3 is divided into a plurality of support substrates 6a in a later step as indicated by broken lines in the insulating substrate 6, and two openings 3a are formed in the longitudinal direction of each of the divided support substrates 6a. Have. The properties such as the size of the opening 3a, the operation, the function, and the like are the same as those described in the first embodiment.

Next, in FIG. 9, the solder bumps 4 are formed on the openings 7a (corresponding to the openings 2a in FIG. 4) of the electrodes 7 located in the openings 3a of the solder resist 3.
Is formed. The properties, functions, functions, and the like of the solder bumps 4 are the same as those described in the first embodiment. As described above, the insulating substrate 6 on which the solder bumps 4 are formed is cut and divided into a plurality of support substrates 6a as indicated by broken lines.

In FIG. 10, the divided support substrate 6a
Are disposed with the solder bump 4 side facing upward, and a piezoelectric element 1 a having electrodes 2 formed on both surfaces thereof is disposed thereon such that a node n indicated by a broken line corresponds to the solder bump 4. FIG. 10 corresponds to FIG. 5 in the first embodiment. Each piezoelectric element 1a is formed by cutting the piezoelectric substrate 1 shown in FIG.

In FIG. 11, a piezoelectric element 1a is placed on a support substrate 6a, and a node n of the piezoelectric element 1a is brought into contact with the solder bump 4, and the solder bump 4 is melted and solidified to form a support 4a. I do. The piezoelectric element 1a has a first
As in the embodiment, the support 4a in which the solder bumps 4 have been melted and solidified and deformed supports the node portion of the vibration in a limited manner. FIG. 11 corresponds to FIG. 6 in the first embodiment. In this case, there is no self-alignment effect due to the melting of the solder bumps 4.

In FIG. 12, the support substrate 6a and the piezoelectric element 1a integrally fixed via the support 4a are immersed in a resist stripping solvent to strip the solder resist 3,
Washed. The remaining electrodes of the piezoelectric element 1a and the support substrate 6a
Each of the electrodes 7 is provided with a lead wire r to form a piezoelectric vibrator.

FIG. 7 manufactured in the first embodiment.
The piezoelectric vibrator shown in FIG. 12 and the piezoelectric vibrator shown in FIG. 12 manufactured in the second embodiment have a two-electrode structure. However, in a vibrating gyroscope or the like, the opposite side of the supporting substrate 6a shown in FIG. The electrode 2 is divided into a plurality of parts to be used as a driving electrode and an electrode for detecting Coriolis force vibration.

In the first embodiment, after the solder resist 3 and the solder bumps 4 are formed on the piezoelectric substrate 1, the piezoelectric substrate 1 is cut. However, after the solder resist 3 is formed on the piezoelectric substrate 1, the piezoelectric element 1a is cut. Cut, then
The solder bump 4 may be formed on the piezoelectric element 1a.

In the second embodiment, the insulating substrate 6
After the solder resist 3 and the solder bumps 4 were formed on the substrate, the insulating substrate 6 was cut.
Is cut into the supporting substrate 6a,
The solder bumps 4 may be formed on the support substrate 6a.

In each of the above embodiments, the piezoelectric substrate 1 and the piezoelectric element 1a have a single plate structure, but may have a bimorph structure or a multilayer structure.

In each of the above embodiments, the solder bump 4
The piezoelectric substrate 1 or the insulating substrate 6 on which the
a or the supporting substrate 5a, respectively, and the piezoelectric element 1a and the supporting substrate 5a were joined by the solder bumps 4. May be bonded via the solder bumps 4 and then the combined body of the piezoelectric substrate 1 and the insulating substrate 6 may be diced into chips (piezoelectric vibrators), and the solder resist 3 may be removed for each chip.

In the above embodiment, the piezoelectric vibrator having a doubly supported structure having two nodes and supporting each of the two nodes has been described, but the present invention relates to a cantilever supporting one node. It can be applied to a piezoelectric vibrator having a structure.

[0034]

According to the present invention, a solder resist having an opening in a piezoelectric element (piezoelectric substrate) or a supporting substrate (insulating substrate) is formed. A solder bump is formed through this opening,
The piezoelectric element is fixed to the support substrate by the support formed by melting and curing the solder bump. Since the shape and size of the support depend on the shape and size of the opening, a support having an arbitrary shape is formed at an appropriate position of the vibration node with high precision and limited, and free vibration is not suppressed. A piezoelectric vibrator having uniform characteristics can be manufactured.

Further, the solder resist has a function of maintaining the piezoelectric vibrator in a horizontal direction with respect to the supporting substrate when the solder bump is melted. The vibrator is properly fixed without tilting.

[Brief description of the drawings]

FIG. 1 is a process diagram of forming electrodes on a piezoelectric substrate in a first embodiment of a method for manufacturing a piezoelectric vibrator according to the present invention.

FIG. 2 is a process diagram of forming a solder resist having a plurality of openings in a piezoelectric substrate.

FIG. 3 is a process diagram of forming solder bumps on a piezoelectric substrate through openings in a solder resist.

FIG. 4 is an enlarged sectional view of an opening of the solder resist shown in FIG. 3;

FIG. 5 is a process diagram of disposing a piezoelectric element on a support substrate.

FIG. 6 is a process diagram of bonding and fixing the supporting substrate and the piezoelectric element by solder bumps.

FIG. 7 is a process chart for removing a solder resist.

FIG. 8 is a process diagram of forming a solder resist having a plurality of openings in an insulating substrate in a second embodiment of the method of manufacturing a piezoelectric vibrator according to the present invention.

FIG. 9 is a process diagram of forming solder bumps on an insulating substrate through openings in a solder resist.

FIG. 10 is a process diagram of disposing a piezoelectric element on a support substrate.

FIG. 11 is a process diagram of bonding and fixing the supporting substrate and the piezoelectric element by solder bumps.

FIG. 12 is a process chart for removing a solder resist.

FIG. 13 is a process diagram of disposing a piezoelectric element on which a solder paste is applied as a support to a support substrate in a conventional method of manufacturing a piezoelectric vibrator.

FIG. 14 is a process diagram of bonding and fixing a support substrate and a piezoelectric element with a solder paste in a conventional method of manufacturing a piezoelectric vibrator.

FIG. 15 is a diagram showing a tilt in a longitudinal direction of a piezoelectric vibrator manufactured by a conventional manufacturing method.

FIG. 16 is a diagram showing a lateral inclination of a piezoelectric vibrator manufactured by a conventional manufacturing method.

FIG. 17 is a diagram showing rotation of a piezoelectric vibrator manufactured by a conventional manufacturing method in a plane direction.

[Explanation of symbols]

 Reference Signs List 1 piezoelectric substrate 1a piezoelectric element 2, 7 electrode 2a, 7a opening portion 3 solder resist 3a opening 4 solder bump 4a support 5 support substrate 5a support electrode 6 insulating substrate 6a support substrate r lead wire

Claims (5)

[Claims] A step of forming a solder resist having an opening in a supporting portion of the piezoelectric element on one main surface of the piezoelectric element on which an electrode is formed; and a step of forming a solder resist having the opening in the solder resist. Forming a solder bump at an opening of the electrode, attaching the piezoelectric element to the support substrate by bonding the solder bump to a support electrode of a support substrate, and removing the solder resist. A method for manufacturing a piezoelectric vibrator. 2. A step of forming a solder resist having a plurality of openings arranged at equal intervals on one main surface of a piezoelectric substrate on which electrodes are formed; Dividing the solder resist into a plurality of piezoelectric elements having a portion, forming solder bumps at the openings of the electrodes located at the openings of the solder resist in the piezoelectric element, and applying the solder bumps to the support electrodes of the support substrate. A method for manufacturing a piezoelectric vibrator, comprising: a step of attaching the piezoelectric element to the support substrate by bonding; and a step of removing the solder resist. 3. A step of forming a solder resist having a plurality of openings arranged at equal intervals on one main surface of a piezoelectric substrate on which electrodes are formed, and the opening of the solder resist in the piezoelectric substrate. Forming a solder bump at an opening of the electrode located at the portion; dividing the piezoelectric substrate into a plurality of piezoelectric elements having the solder bump; coupling the solder bump of the piezoelectric element to a support electrode of a support substrate. A step of attaching the piezoelectric element to the support substrate, and a step of removing the solder resist. 4. A step of forming a solder resist having at least one opening on one main surface of a support substrate on which an electrode is formed; and forming the electrode on the support substrate at the opening of the solder resist on the support substrate. Forming a solder bump at the opening of the piezoelectric element; attaching the piezoelectric element to the support substrate by coupling a supporting portion of the piezoelectric element to the solder bump; and removing the solder resist. Child manufacturing method. 5. A step of forming a solder resist having a plurality of openings on one main surface of a piezoelectric substrate on which electrodes are formed, and said electrode located at said opening of said solder resist on said piezoelectric substrate. Forming a solder bump at the opening of the piezoelectric substrate, and attaching the piezoelectric substrate to the insulating substrate by coupling the solder bump of the piezoelectric substrate to the supporting electrode of the insulating substrate on which a plurality of supporting electrodes are formed. A method of dividing the combined body of the piezoelectric substrate and the insulating substrate into a plurality of piezoelectric vibrators; and a step of removing the solder resist.