JP6972879B2 - Manufacturing method of electromechanical conversion element, liquid discharge head, liquid discharge unit, liquid discharge device, ultrasonic generator, and electromechanical conversion element - Google Patents

Description

The present invention relates to an electromechanical conversion element, a liquid discharge head, a liquid discharge unit, a device for discharging a liquid, an ultrasonic generator, and a method for manufacturing an electromechanical conversion element.

Piezoelectric elements are used as pressure generating means for droplet heads used in inkjet recording devices, ultrasonic generating elements for ultrasonic diagnostic devices, and electromechanical conversion elements in a wide range of applications. With regard to piezoelectric elements, recent advances in MEMS (Micro Electro Electro Mechanical Systems) technology, which performs microfabrication using lithography technology, have led to the development of piezoelectric elements using a thin film piezoelectric body formed on a substrate. As a result, the increase in the integration of piezoelectric elements has progressed, which has contributed to the miniaturization and higher definition of devices using the piezoelectric elements.

In the thin film piezoelectric element used in the MEMS technology, for example, a lower electrode (first electrode), a piezoelectric layer, and an upper electrode (second electrode) are each formed and laminated by using the thin film film forming technology. Many of them are composed of configurations. Of these, it is known that an oxide such as lead zirconate titantate (hereinafter referred to as PZT) or the like is used for the piezoelectric layer. The formation of such a piezoelectric layer includes a vapor deposition method, a sputtering method (hereinafter abbreviated as a sputtering method), a chemical vapor deposition method (hereinafter abbreviated as a CVD method), a vapor phase growth method represented by a chemical vapor deposition method, and a chemistry method. A liquid phase growth method typified by a solution deposition method (CSD method: Chemical Solution Deposition method), a hydrothermal synthesis method, or the like is used.

Among the liquid phase growth methods, the CSD method is widely adopted because the composition control is easy, the thin film can be easily produced with good reproducibility, the cost required for the production equipment is low, and mass production is possible. In the CSD method, a coating step of applying the precursor solution and a firing step of firing the coating film formed by the coating step are performed. When the piezoelectric layer is formed by the CSD method, the precursor solution for the piezoelectric layer is applied onto the lower electrode in the coating step, and the coating film using the precursor solution is dried in the firing step (drying step). After that, the organic matter contained in the coating film is thermally decomposed (thermal decomposition step), and the thermally decomposed coating film is crystallized by heating (crystallization step).

Further, in order to make the piezoelectric layer a layer patterned into a predetermined shape, a film forming method combining the above CSD method and the inkjet method has been proposed. In the film forming method combined with this inkjet, the piezoelectric film can be formed only on the portion to be the piezoelectric element, instead of forming the piezoelectric film on the entire surface of the substrate (see Patent Document 1). As a result, there is an advantage that etching of a piezoelectric material such as PZT, which is generally difficult to etch, can be omitted.

In order to form the upper electrode of the piezoelectric element, it is generally performed that the upper electrode is formed on the piezoelectric layer by sputtering or the like, and then patterned by photolithography or etching. In Patent Document 2, the upper electrode layer and the individual upper electrode layer are patterned by a photolithography technique. Patent Document 2 states that cracks are prevented by extending a piezoelectric layer or an electrode to a region where bending deformation is hindered.

Further, as the material of the upper electrode, the same material as that of the lower electrode is often used. For example, platinum, which can withstand a process temperature of several hundred degrees or more and has little diffusion into the piezoelectric layer, is used for both the upper electrode and the lower electrode. Further, in the etching, in order to minimize the variation in dimensions and the amount of scraping of the lower layer, it is generally performed to set the etching time for each wafer while detecting the end point of the etching for each wafer. .. For example, in the case of dry etching, it is generally performed to detect the end point of etching by monitoring the spectral change (change in light intensity of a specific wavelength) of plasma emission during etching.

At this time, in the method of combining the CSD method and the inkjet method, when the piezoelectric film is arranged only in the portion to be the piezoelectric element, if the same material is used for the upper electrode and the lower electrode, the following problems occur. .. Since the exposed areas of the upper electrode and the lower electrode, which are the same material, do not change much between the time when the upper electrode is etched and the time when the etching of the upper electrode is completed, the spectrum change of plasma emission during the dry etching is performed. It was difficult to detect the etching end point.

For such a problem, it is common to perform etching with a fixed etching time based on data acquired in advance.
However, in this case, the cost increases because the man-hours for acquiring the data in advance are required. Furthermore, since it is not possible to correct the thickness variation and etching rate variation of the layer to be etched for each wafer during data acquisition, the dimensional variation and the amount of scraping of the base layer are larger than when etching while detecting the end point for each wafer. The variation becomes large.

For the purpose of solving such a problem, for example, the configuration as in Patent Document 3 can be mentioned. In Patent Document 3, the patterning of the upper electrode is etched only in the vicinity of the outer periphery on the piezoelectric layer. With such a configuration, in the etching mask opening, only the piezoelectric layer is exposed after the etching of the upper electrode is completed, and it becomes easy to detect the end point of etching by the plasma emission monitor. Further, since the lower electrode is structurally not etched, it is possible to prevent the resistance variation of the lower electrode from becoming large even if the endpoint is not monitored.

On the other hand, in actual device fabrication, it is common to perform patterning by leaving only the necessary portion, instead of leaving the lower electrode on the entire surface of the substrate. Reasons for this include, for example, reduction of parasitic capacitance between the upper electrode lead-out wiring and the lower electrode, prevention of film peeling of the lower electrode, request for removal of the metal film on the dicing street, and device configuration necessity.

For these, for example, it is desirable to do the following.
Regarding the parasitic capacitance between the upper electrode lead-out wiring and the lower electrode, it is desirable to minimize the overlap area with the upper electrode wiring layer by minimizing the area of the lower electrode.
Regarding the peeling of the film of the lower electrode, platinum or the like, which is difficult to deteriorate even at a high temperature, is generally used for the lower electrode, but the disadvantage is that the adhesion to the underlying film is rather small. Therefore, for products, the probability of peeling due to improvement of the adhesion layer is kept sufficiently small, but there is a possibility that there is an inherent risk of film peeling due to fluctuations in the equipment state, so the electrode area should be kept to the minimum necessary. Is desirable.
Regarding the removal of the metal film on the dicing street, it is essential to remove the metal film that reflects the laser in the case of dicing using a laser, and even in the case of blade dicing, the metal is used to reduce clogging of the blade. It is desirable to remove the membrane.
Regarding the requirements for device configuration, in the case of a device type, for example, a droplet ejection head, a liquid flow path may be formed through a substrate on which a piezoelectric element is formed. In that case, it is necessary to etch the lower electrode as well, and it is desirable to remove the lower electrode at that location in advance.

Therefore, in consideration of the above, the patterning of the lower electrode is performed separately as an independent process separately from the process of manufacturing the upper electrode and the piezoelectric layer.
However, if the patterning of the lower electrode is performed separately as an independent process, the manufacturing cost increases with the increase in the number of processes and the damage to the piezoelectric element increases, and when the damage to the piezoelectric element increases, the characteristics of the piezoelectric element deteriorate. Is a concern.
On the other hand, if the patterning of the lower electrode is not performed as an independent process, it is difficult to make the lower electrode the desired area as described above, and for example, the parasitic capacitance between the upper electrode lead-out wiring and the lower electrode increases. There is a problem that characteristics such as high frequency characteristics and power consumption are deteriorated.

In view of the above problems, the present invention provides an electromechanical conversion element capable of suppressing wiring resistance of a common electrode, improving high frequency characteristics and suppressing power consumption, and suppressing manufacturing costs. The purpose.

In order to solve the above problems, the present invention presents the first electrode layer formed on the substrate, the electromechanical conversion film formed on the first electrode layer, and the first electrode layer and the like. An electromechanical conversion element having a second electrode layer formed on the electromechanical conversion film, wherein the first electrode layer is formed on a part of the substrate and the second electrode is formed. The layer is formed in contact with the first portion formed only on the electromechanical conversion film, on the first electrode layer and on the electromechanical conversion film, and is formed separately from the first portion. It is characterized in that the outer edge of the portion in contact with the first electrode layer and the second portion located outside the end portion of the substrate is the same.

According to the present invention, it is possible to suppress the wiring resistance of a common electrode, improve high frequency characteristics, suppress power consumption, and provide an electromechanical conversion element with reduced manufacturing cost.

It is a top view in an example of the ultrasonic wave generator using the electromechanical conversion element of this invention. It is an example of the cross-sectional view in the ultrasonic wave generator of FIG. It is a manufacturing process flow (a)-(d) for demonstrating an example of the manufacturing method of the electromechanical conversion element of this invention. It is a manufacturing process flow (e)-(h) for demonstrating an example of the manufacturing method of the electromechanical conversion element of this invention. It is a manufacturing process flow (i)-(k) for demonstrating an example of the manufacturing method of the electromechanical conversion element of this invention. It is a top view in the example of the liquid discharge head of this invention. It is an example of the cross-sectional view of the liquid discharge head of FIG. It is a manufacturing process flow (a)-(d) for demonstrating the manufacturing method of the liquid discharge head of FIG. It is a manufacturing process flow (e)-(f) for demonstrating the manufacturing method of the liquid discharge head of FIG. It is a top view in another example of the liquid discharge head of this invention. It is an example of the cross-sectional view of the liquid discharge head of FIG. It is another example of the cross-sectional view of the liquid discharge head of FIG. 8 is a manufacturing process flow (a) to (e) corresponding to FIG. 8 for explaining the manufacturing method of the liquid discharge head of FIG. 7. 8 is a manufacturing process flow (f) to (h) corresponding to FIG. 8 for explaining the manufacturing method of the liquid discharge head of FIG. 7. 9 is a manufacturing process flow (a) to (e) corresponding to FIG. 9 for explaining the manufacturing method of the liquid discharge head of FIG. 7. 9 is a manufacturing process flow (f) to (h) corresponding to FIG. 9 for explaining the manufacturing method of the liquid discharge head of FIG. 7. It is a schematic diagram which shows an example of the apparatus which discharges a liquid which concerns on this invention. It is a schematic diagram which shows the other example of the apparatus which discharges a liquid which concerns on this invention. It is a schematic diagram which shows an example of the liquid discharge unit which concerns on this invention. It is a schematic diagram which shows the other example of the liquid discharge unit which concerns on this invention.

Hereinafter, a method for manufacturing an electromechanical conversion element, a liquid discharge head, a liquid discharge unit, a device for discharging a liquid, an ultrasonic generator, and an electromechanical conversion element according to the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited to the embodiments shown below, and can be modified within the range conceivable by those skilled in the art, such as other embodiments, additions, modifications, and deletions. However, as long as the action and effect of the present invention are exhibited, it is included in the scope of the present invention.

The present invention is formed on a first electrode layer formed on a substrate, an electromechanical conversion film formed on the first electrode layer, and on the first electrode layer and the electromechanical conversion film. The electromechanical conversion element having the second electrode layer formed therein, wherein the second electrode layer has a first portion formed only on the electromechanical conversion film and the first electrode layer. The upper part and the second part formed in contact with the electromechanical conversion film and separated from the first part are formed, and the second part is formed on the electromechanical conversion film. It is characterized in that the outer edge of the portion in contact with the first electrode layer and the second portion is the same except for the portion.

The present invention provides a method for manufacturing an electromechanical conversion element, a liquid discharge head, a liquid discharge unit, a device for discharging a liquid, an ultrasonic generator, and an electromechanical conversion element. Further, the liquid discharge head, the liquid discharge unit, and the device for discharging the liquid can be used for a three-dimensional molding technique using an inkjet technique, and the ultrasonic generator can be used for an ultrasonic diagnostic device or the like.
Hereinafter, the electromechanical conversion element may be referred to as a piezoelectric element, and the electromechanical conversion film may be referred to as a piezoelectric body or a piezoelectric film.

(First Embodiment)
The schematic diagram of the electromechanical conversion element (piezoelectric element) of this embodiment is shown in FIGS. 1 and 2. 1 and 2 are examples of an ultrasonic wave generator using the electromechanical conversion element of the present embodiment. FIG. 1 is a plan layout view of a main part of the present embodiment, and FIG. 2 corresponds to a cross section taken along the line AA'in FIG. It should be noted that the figures are schematically shown, and the scale ratios in the figures and the scale ratios between the figures may differ from the actual ones.

In the present embodiment, as shown in FIG. 2, the substrate 10, the voids 11 formed in the substrate 10, the silicon oxide film 19, the vibrating plate 20, the first insulating film 21, the first electrode layer 22, and the first. The piezoelectric body 23 of 1, the second piezoelectric body 24, the second electrode layer 25, the second insulating film 26, the opening 27 in the second insulating film, the wiring 28, the protective film 29, and the electrode terminal 30 are illustrated. ing. Further, as the second electrode layer 25, the first portion 25a and the second portion 25b are shown.
Then, in FIG. 1, the first electrode layer 22, the first portion 25a, the second portion 25b, the first piezoelectric body 23, the second piezoelectric body 24, the opening 27, and the wiring in the second electrode layer 25. 28, the electrode terminal 30 is shown as a plan view.

In the present embodiment, the first electrode layer 22 is a lower electrode of the piezoelectric element, and the first portion 25a in the second electrode layer 25 is an upper electrode of the piezoelectric element. Further, the second portion 25b in the second electrode layer 25 is formed in contact with the first electrode layer 22 and the piezoelectric body (second piezoelectric body 24), and is formed together with the first electrode layer 22 as a common electrode. It has become.

In the present embodiment, a driving voltage is applied between the upper electrode and the lower electrode to generate a driving force in the piezoelectric body (the first piezoelectric body 23 and the second piezoelectric body 24) to vibrate the vibrating plate 20. This generates ultrasonic waves. The drive voltage is supplied from the outside via the electrode terminal 30 and the wiring 28. Multiple oscillator groups consisting of multiple individual oscillators (3 in FIG. 1) that are driven at the same time are arranged (5 groups in FIG. 1), the upper electrode is an individual electrode for each oscillator group, and the lower electrode is the entire element. It is a common electrode. It should be noted that the actual number of individual oscillators is usually much larger than that shown in the figure.

For the substrate 10, it is preferable to use a material having excellent heat resistance, sufficient rigidity and strength, and being easily etched, and a single crystal silicon substrate is preferably used. A recess is formed in the substrate 10, and a diaphragm 20 is provided on the recess, and the diaphragm 10 is joined at a portion other than the recess. The recess becomes a gap 11 surrounded by the substrate 10 and the diaphragm 20. The gap 11 is for not interfering with the operation of the piezoelectric element described later.

The diaphragm 20 can use single crystal silicon and can be formed by using a technique for manufacturing an SOI substrate. In the present embodiment, the substrate 10 which is a single crystal silicon substrate having a recess formed and another single crystal silicon substrate are directly bonded via a thermal oxide film (silicon oxide film 19), and then the required thickness is obtained by grinding and polishing. Processed into a diaphragm. Although it can be changed as appropriate, the gap 11 can be about Φ60 μm, the depth can be about 1 μm, and the thickness of the diaphragm 20 can be about 5 μm. Further, the thermal oxide film (silicon oxide film 19) between the single crystal silicon substrates can be about 0.5 μm.

A first insulating film 21 is formed on the diaphragm 20, and a piezoelectric element having the following configuration is formed on the first insulating film 21 as an electromechanical conversion element. The piezoelectric element of the present embodiment is formed from the first electrode layer 22, the first piezoelectric body 23, the second piezoelectric body 24, and the first portion 25a in the second electrode layer 25, which is the upper electrode. Become.

In the present embodiment, the first electrode layer 22 is formed on the diaphragm 20 via the first insulating film 21. For example, platinum (Pt) can be used as the first electrode layer 22, and an adhesive layer may be provided between the first electrode layer 22 and the first insulating film 21. As the adhesion layer, for example, TiO ₂ can be used.

In the present embodiment, the first piezoelectric body 23 is _{composed of a laminated film of lead titanate (PbTiO 3} ) and lead zirconate titanate (PZT). The lead titanate layer also functions as a seed layer for the lead zirconate titanate layer. The lead zirconate titanate layer also functions as a wettability control film when the precursor of the second piezoelectric body 24 is applied and as a seed layer when the second piezoelectric body 24 is crystallized.

The second piezoelectric body 24 of the present embodiment is lead zirconate titanate (PZT). The first piezoelectric body 23 and the second piezoelectric body 24 are shown separately for the convenience of manufacturing, but when used, they function and operate as an integral piezoelectric body. As appropriate, the first piezoelectric body 23 and the second piezoelectric body 24 may be collectively referred to as an electromechanical conversion film, a piezoelectric body, or a piezoelectric film.

Platinum (Pt) can be used for the second electrode layer 25 as in the first electrode layer 22. The second electrode layer 25 is separated into a first portion 25a and a second portion 25b. The first portion 25a of the second electrode is formed only on the electromechanical conversion film and serves as an upper electrode of the piezoelectric element. The second portion 25b of the second electrode is formed from the electromechanical conversion film to the portion where the electromechanical conversion film is not formed, and is formed on the first electrode layer 22 and the electromechanical conversion film (second piezoelectric). It is formed in contact with the body 24).

The second portion 25b of the second electrode is connected to the first electrode layer 22 and functions as a part of the common electrode of the piezoelectric element. As a result, the wiring resistance of the common electrode can be reduced as compared with the case where the second portion 25b is not arranged.

The details will be described in the process flow described later, but in the present embodiment, the separation groove 18 is formed in the electromechanical conversion membrane, and the first portion 25a and the second portion 25b are separated with the separation groove 18 as a boundary. Has been done.

The common electrode composed of the first electrode layer 22 and the second portion 25b in the second electrode layer is patterned on the outside of the plurality of piezoelectric element groups so that the two layers have substantially the same outer peripheral shape. Has been done. As a result, the outer edge of the portion where the first electrode layer 22 and the second portion 25b are in contact with each other is the same. That is, in the portion where the second portion 25b of the first electrode layer 22 and the second electrode layer 25 is directly laminated, their outer peripheral shapes are exactly the same and have an integral side surface shape. By doing so, the area where the common electrodes are arranged is not made wider than necessary.

Further, in the present embodiment, the separation groove 18 is formed in the electromechanical conversion film, and when viewed from the direction perpendicular to the surface direction of the electromechanical conversion element, the first electrode is removed except for the separation groove 18. The layer 22 and the second electrode layer 25 have the same area. As a result, the wiring resistance of the lower electrode as the common electrode can be further reduced, so that an electromechanical conversion element having higher high frequency characteristics can be obtained.

A second insulating film 26 is formed on the substrate on which the piezoelectric element is formed. The second insulating film 26 plays a role of ensuring the insulating property of the wiring 28 and the lower electrode layer, preventing moisture absorption of the piezoelectric element, and preventing damage in the subsequent process. As the second insulating film 26, for example, a silicon oxide film can be used, and the thickness can be about 1 μm.

An opening 27 is formed at a predetermined position of the second insulating film 26. Further, a wiring 28 is formed on the wiring 28, and is connected to the first portion 25a or the second portion 25b in the second electrode layer at the opening 27 of the insulating film.

Further, the wiring 28 has an electrode terminal 30 whose end is an electrical connection with the outside. As the wiring 28, for example, a titanium film having a thickness of about 50 nm on which copper-added aluminum having a thickness of about 1 μm is laminated can be used.

A protective film 29 is formed on the wiring 28 to protect the wiring 28 from corrosion and the like. As the protective film 29, for example, a silicon nitride film having a thickness of about 1 μm can be used. Further, the protective film 29 is opened at the electrode terminal 30 to enable electrical connection with the outside.

In the present embodiment, the arrangement region of the common electrode consisting of the first electrode layer and the second portion of the second electrode layer is defined as a region where the piezoelectric element is formed, a connection region with wiring, and necessary for processing. It is limited to the margin area so that it does not become wider than necessary. As a result, the parasitic capacitance between the upper electrode lead-out wiring and the common electrode (lower electrode) is reduced as compared with the case where the second portion of the first electrode layer and the second electrode layer is left on the entire surface without patterning. This makes it possible to improve the high frequency characteristics of the piezoelectric element and suppress power consumption.

Further, since the arrangement region of the common electrode is suppressed, the probability that the film peeling of the common electrode occurs can be reduced, and the yield can be improved. Further, although not shown in the present embodiment, the electrode material on the dicing street is removed, and it is possible to make a chip by laser dicing.

Next, the manufacturing method of the electromechanical conversion element of the present embodiment will be described with reference to the manufacturing process flow of FIGS. 3A to 3C.
In FIG. 3A (a), the first insulating film 21, the first electrode layer 22, and the first piezoelectric body 23 are formed on the substrate 10 on which the gap 11 and the diaphragm 20 are formed.
As described above, the substrate 10 on which the voids 11 and the diaphragm 20 are formed is manufactured by using the SOI substrate manufacturing technique and using the substrate 10 in which the recesses to be the voids 11 are formed in advance at that time. be. The first insulating film 21 can be formed by, for example, thermally oxidizing a diaphragm 20 made of silicon.

Regarding the first electrode layer 22, first, titanium dioxide (TiO ₂ ) having a thickness of about 100 nm is formed as an adhesion layer. In that method, for example, titanium (Ti) is formed into a film of about 60 nm by a sputtering method, and then RTA (Rapid Thermal Annealing) is performed in a state where oxygen is flowing to oxidize the titanium (Ti). A platinum (Pt) layer, which is the first electrode layer 22, is formed on the platinum (Pt) layer by a sputtering method to form a film having a thickness of about 200 nm.

The first piezoelectric body 23 formed on the first electrode layer 22 is, for example, a laminated film of lead titanate and lead zirconate titanate, and is formed on the entire surface of the substrate by the CSD method. Specifically, a precursor solution using lead acetate or a titanium alkoxide compound as a starting material is spin-coated on the first electrode layer 22 and then dried. Further, a precursor solution using lead acetate, a zirconium alkoxide compound, and a titanium alkoxide compound as starting materials is spin-coated, and then dried, thermally decomposed, and crystallized.

The layer thicknesses of lead titanate and lead zirconate titanate can be about 5 nm and about 75 nm, respectively. The lead titanate layer acts as a seed layer during crystallization of the laminated film and has a function of improving crystallinity. The lead zirconate titanate layer functions as a wettability control film when a part of the piezoelectric layer and the piezoelectric precursor are selectively applied in a later step.

In FIG. 3A (b), the first piezoelectric body 23 is patterned into a desired shape by photolithography and etching. Etching can be performed by wet etching using, for example, fluorine nitric acid.

In FIG. 3A (c), the water-repellent film 41 is selectively formed only on the first electrode layer 22 made of platinum. Specifically, for example, the procedure is as follows.
(1) Clean the surface by pretreatment (acid cleaning).
(2) Spin-coat a solution obtained by diluting alkanethiol with an organic solvent (alcohol, acetone, toluene, etc.). In addition, in order to strengthen the water repellency, it is preferable to use a liquid containing fluorine.
(3) Wash with an organic solvent (alcohol, acetone, toluene, etc.) to remove excess water-repellent membrane material.
According to this procedure, the water-repellent film 41 is not formed on the first piezoelectric body 23, and is maintained as a hydrophilic portion (parent CSD liquid portion).

In FIG. 3A (d), in the CSD liquid coating device equipped with the CSD liquid discharge head (precursor liquid discharge head 42), the precursor of the second piezoelectric body 24 is formed on the desired first piezoelectric body 23. Selectively apply the CSD solution. In the CSD liquid coating apparatus, while the CSD liquid discharge head moves on the substrate (or the substrate moves under the head), the CSD liquid is discharged only when the relative position between the head and the substrate is in a predetermined position. Thereby, the CSD solution can be selectively applied only to the desired portion.

At this time, if the wettability of the substrate surface is not controlled, the shape of the CSD liquid application pattern varies due to variations in the landing position of the CSD droplets and variations in the wett spread state. In order to prevent this, in the present embodiment, it is preferable that the surface of the portion forming the second piezoelectric body 24 is hydrophilic in advance and the outer peripheral surface thereof is water repellent. When CSD droplets are applied to a substrate in such a surface state, the CSD liquid is applied to the entire hydrophilic region and at the same time the CSD liquid is applied to the water-repellent region even if there is some variation in the landing position of the CSD liquid. Can be left unpainted.

Next, the partially applied CSD solution is dried, thermally decomposed, and crystallized. It is preferable to adjust the coating amount of the CSD solution so that the crystallized film has a size of about 100 nm. The thicker the film thickness formed at one time, the higher the productivity, but the thicker the film thickness, the more easily cracks are likely to occur in the formed film.

Then, the steps of water-repellent film formation, selective coating of CSD solution, drying, thermal decomposition, and crystallization are repeated until the second piezoelectric body 24 has a desired thickness. In the present embodiment, the above steps are repeated about 20 times to form a second piezoelectric body 24 having a thickness of about 2 μm.

In FIG. 3B (e), for example, a platinum film is formed as the second electrode layer 25 by a sputtering method. The thickness can be about 100 nm.

In FIG. 3B (f), a resist 40 is formed on the second electrode layer 25, and a predetermined resist pattern is formed by a photolithography.

In FIG. 3B (g), the second electrode layer 25 is etched using the resist 40 as a mask. Etching is performed by, for example, a dry etcher using ICP (Inductively Coupled Plasma) as a plasma source, and chlorine is used as the etchant.

In FIG. 3B (h), etching is continuously performed from the step of FIG. 3B (g), and the first electrode layer 22 is etched. As a result, the first electrode layer 22 in the portion outside the common electrode layer where the first electrode layer 22 is exposed is removed from the resist opening.

On the other hand, since the second piezoelectric body 24 is formed in the other resist openings, the second piezoelectric body 24 is only slightly etched, and there is no major structural change. However, it is preferable to design the resist mask in that way.

In the present embodiment, the electromechanical conversion film (second piezoelectric body 24) is slightly etched by the above etching to form the separation groove 18. Here, the first portion 25a and the second portion 25b are separated by a separation groove 18. The second electrode layer 25 may be separated into the first portion 25a and the second portion 25b, and the separation groove 18 may not be formed. When the separation groove 18 is formed, it can be said that the first portion 25a and the second portion 25b are surely separated.

Further, here, for convenience, FIGS. 3B (g) and 3B (h) are shown and described separately, but in reality, these are continuously performed as substantially the same process. That is, the second electrode layer 25 is etched using a mask, and the first electrode layer 22 is continuously etched using the same mask, so that the first electrode layer 22 and the second portion 25b are formed. The outer edges of the contacting parts are made the same.

Therefore, the number of steps is not increased and the time of the steps is slightly longer than that of the conventional configuration in which the common electrode layer is left on the entire surface. Therefore, the increase in manufacturing cost does not occur substantially. Further, as compared with the case where the common electrode layer is processed by a separate independent mask, the photolithography step can be reduced once, so that the manufacturing cost can be reduced.
Further, in the resist removing step, dry ashing is usually performed by oxygen plasma, but according to this embodiment, the photolithography step can be reduced, so that oxygen plasma or a piezoelectric material generated by ultraviolet rays generated at that time can be used. Process damage can be reduced.

In FIG. 3C (i), a second insulating film 26 is formed on the insulating film 26. In the present embodiment, for example, by a plasma CVD method, monosilane _(SiH 4), nitrous oxide _(N 2 O) gas to 1μm about deposition as a raw material.

In FIG. 3C (j), an opening 27 is formed in the second insulating film 26 by photolithography and etching, and then a wiring material is formed and patterned to form the wiring 28.
The etching of the second insulating film 26 is performed by, for example, dry etching (RIE, Reactive Ion Etching) using _{CF 4} and CHF _{3 as etchants.}

As the wiring 28, for example, titanium is formed to form a film of about 50 nm as an adhesion layer with platinum, and then aluminum to which copper is added is formed to form a film of about 1 μm as the main wiring material. Both can be formed by, for example, spattering. After that, the wiring material is patterned by photolithography and etching to form the wiring 28.
Etching of the wiring material is performed by, for example, dry etching using chlorine and boron trichloride as an etchant.

In FIG. 3C (k), the protective film 29 is formed and only the electrode terminal portion is opened. In the present embodiment, as the protective film 29, a silicon nitride film of about 1 μm is formed from _{monosilane (SiH 4} ) and nitrous oxide ammonia (NH _{3) gas as raw materials by, for example, a plasma CVD method.} Aperture is performed by photolithography and etching process, and etching is performed by dry etching (RIE) using _{CF 4} and CHF _{3 as etchants, for example.}

In this way, the electromechanical conversion element of the present embodiment and the ultrasonic wave generator having the electromechanical conversion element can be obtained.
As described above, according to the manufacturing method of the present embodiment, the upper electrode and the lower electrode can be patterned only by continuously etching the second electrode layer and the first electrode layer with the same mask pattern. Therefore, the process can be shortened and the manufacturing cost can be reduced as compared with the case where the upper electrode and the lower electrode are patterned with different masks. Further, by shortening the process, the process damage of the electromechanical conversion element is reduced, and the characteristics can be improved.

(Second embodiment)
Next, the schematic diagram of the liquid discharge head of this embodiment is shown in FIGS. 4 and 5. FIG. 4 is a plan layout view of a main part of the present embodiment, and FIG. 5 corresponds to a cross section taken along the line AA'in FIG. FIG. 5 is shown according to the top and bottom in the actual use state, but if it is turned upside down, it has basically the same layer structure as that of FIG. The same matters as in the above embodiment will be omitted.

In the present embodiment, as shown in FIG. 5, the substrate 10, the liquid chamber 12 formed in the substrate 10, the diaphragm 20, the nozzle hole 14 formed through the diaphragm 20, and the like, and the first insulating film are formed. 21, 1st electrode layer 22, 1st piezoelectric 23, 2nd piezoelectric 24, 2nd electrode layer 25, 2nd insulating film 26, opening 27 of 2nd insulating layer, wiring 28, The protective film 29 and the electrode terminal 30 are shown in the figure.
Then, in FIG. 4, the nozzle hole 14, the separation groove 18, the first electrode layer 22, the first portion 25a, the second portion 25b, the first piezoelectric body 23, and the second piezoelectric in the second electrode layer 25 are formed. The body 24, the opening 27, the wiring 28, and the electrode terminal 30 are shown as a plan view.

In the present embodiment, the first electrode layer 22 is a lower electrode of the piezoelectric element, and the first portion 25a in the second electrode layer 25 is an upper electrode of the piezoelectric element. Further, the second portion 25b in the second electrode layer 25 is formed in contact with the first electrode layer 22 and the piezoelectric body (second piezoelectric body 24), and is formed together with the first electrode layer 22 as a common electrode. It has become.
Here, the upper and lower parts of the electrode are defined not as the upper and lower parts in the used state but as the upper and lower parts when the element forming surface is turned down. Therefore, it is upside down in FIG.

In the present embodiment, a driving voltage is applied between the upper electrode and the lower electrode to generate a driving force in the piezoelectric body (the first piezoelectric body 23 and the second piezoelectric body 24). As a result, the liquid in the liquid chamber 12 is pressurized by vibrating the diaphragm 20, and the liquid is discharged from the nozzle hole 14. The drive voltage is supplied from the outside via the electrode terminal 30 and the wiring 28. The upper electrode is an individual electrode for each nozzle, and the lower electrode is a common electrode for the entire head so that the liquid can be discharged individually for each nozzle. The actual number of nozzles is usually much larger than that shown in the figure.

As the substrate 10, a single crystal silicon substrate is preferably used as in the first embodiment. Further, the diaphragm 20 can use single crystal silicon as in the first embodiment, and can be formed by using the SOI substrate manufacturing technique. Therefore, the SOI wafer can be used as in the first embodiment. However, in this embodiment, a normal SOI wafer is used instead of forming voids in the substrate 10 in advance.
Further, the liquid chamber 12 is formed by forming a piezoelectric element or the like and then etching a substrate 10 from a surface opposite to the element. The liquid is supplied to the liquid chamber 12 through the supply path.

In this embodiment, a substrate 10 having a thickness of about 400 μm can be used. The liquid chamber 12 can be about Φ1 mm, and the depth can be about 400 μm, which is the thickness of the substrate. The thickness of the diaphragm 20 can be about 20 μm. Further, the thermal oxide film (silicon oxide film 19) between the single crystal silicon layers can be about 0.5 μm.

The layer structure of the piezoelectric element on the diaphragm 20 is basically the same as that of the first embodiment.
Also in this embodiment, the second electrode layer 25 is in contact with the first portion 25a formed only on the electromechanical conversion film, on the first electrode layer 22 and on the electromechanical conversion film (piezoelectric body). It is composed of a first portion 25a and a second portion 25b formed separately from the first portion 25a.

The first portion 25a is formed only on the electromechanical conversion film (on the second piezoelectric body 24), and serves as an upper electrode (individual electrode) of the piezoelectric element. The second portion 25b is formed from the top of the piezoelectric body to the portion where the piezoelectric body is not formed, is connected to the first electrode layer 22, and functions as a part of the common electrode of the piezoelectric element. As a result, the wiring resistance of the common electrode can be reduced as compared with the case where the second portion 25b is not arranged.

As shown in FIG. 4, the piezoelectric body (first piezoelectric body 23, second piezoelectric body 24) and the first portion 25a in the second electrode layer 25 of the present embodiment are circular except for the central portion. It is formed as an annular shape formed in a shape. The common electrode composed of the first electrode layer 22 and the second portion 25b is patterned so that the two layers have substantially the same outer peripheral shape on the outside of the piezoelectric element and around the nozzle. That is, the outer edges of the portions where the first electrode layer 22 and the second portion 25b are in contact are the same, and the areas of the first electrode layer 22 and the second portion 25b inside the annular shape are the same.
Further, when viewed from the direction perpendicular to the plane direction, the first electrode layer 22 and the second electrode layer 25 have the same area except for the separation groove.

Also in the present embodiment, as in the first embodiment, the area where the piezoelectric element is formed and the wiring are defined in the area where the common electrode is arranged, which is the second portion of the first electrode layer and the second electrode layer. The area is limited to the connection area with and the margin area required for processing, so that the area is not wider than necessary. As a result, the parasitic capacitance between the upper electrode lead-out wiring and the common electrode (lower electrode) is reduced as compared with the case where the second part of the first electrode layer and the second electrode layer is left on the entire surface without patterning. This makes it possible to improve the high frequency characteristics of the piezoelectric element and suppress power consumption.

Further, since the arrangement region of the common electrode is suppressed, the probability that the film peeling of the common electrode occurs can be reduced, and the yield can be improved. Further, although not shown in the present embodiment, the electrode material on the dicing street is removed, and it is possible to make a chip by laser dicing.

In addition to the above, in the present embodiment, since the two layers are patterned (removed) so as to have substantially the same outer peripheral shape even around the nozzle (inside the annular shape), a common electrode is used when the nozzle is opened. The step of etching and removing the material becomes unnecessary.

Further, since the common electrode layer is patterned (removed) larger than the nozzle opening ((A) in FIG. 5) ((B) in FIG. 5), the discharged liquid can be discharged into the nozzle hole without adding a special process. The structure can be configured so as not to contact the common electrode on the side surface. Therefore, for example, even when a bias voltage is applied to the common electrode, it is possible to prevent the generation of a leak current to the discharge liquid side, the malfunction of the device due to it, the deterioration of the discharge liquid, etc. without adding a special process. Can be done.

Next, the manufacturing method of the electromechanical conversion element of the present embodiment will be described with reference to the manufacturing process flow of FIG.
In FIG. 6A (a), the first insulating film 21, the first electrode layer 22, and the first piezoelectric body 23 are formed on the substrate 10 on which the diaphragm 20 is formed, as in the first embodiment. do. Here, in this embodiment, an SOI substrate in which voids are not formed is used. After that, the first piezoelectric body 23 is patterned into a desired shape by photolithography and etching, the second piezoelectric body 24 is formed only at a desired position by using inkjet technology, and the second electrode layer 25 is formed on the second piezoelectric body 24. Is formed into a film. Next, a resist mask (resist 40) having a pattern that can separate the second electrode layer 25 into the first portion 25a and the second portion 25b and remove the electrode layer in the excess region is formed.

In FIG. 6A (b), the second electrode layer 25 is etched using the resist 40 as a mask. As a result, the second electrode layer 25 is separated into a first portion 25a and a second portion 25b.

In FIG. 6A (c), etching is continuously performed from FIG. 6A (b), and the first electrode layer 22 is etched. As a result, the first electrode layer 22 in the outer portion of the common electrode to which the first electrode layer 22 is exposed is removed from the resist opening. On the other hand, since the second piezoelectric body 24 is formed in the other resist openings, the second piezoelectric body 24 is only slightly etched, and there is no major structural change. However, it is preferable to design the resist mask in that way.
As in the first embodiment, the piezoelectric body (second piezoelectric body 24) is slightly etched to form the separation groove 18, but the separation groove 18 may not be present.

Further, here, for convenience, FIGS. 6A (b) and 6A (c) are shown and described separately, but in reality, these are continuously performed as substantially the same process. That is, the second electrode layer 25 is etched using a mask, and the first electrode layer 22 is continuously etched using the same mask, so that the first electrode layer 22 and the second portion 25b are formed. The outer edges of the contacting parts are made the same. Furthermore, the inside of the annular shape has the same shape.
Therefore, the number of steps is not increased and the time of the steps is slightly longer than that of the conventional configuration in which the common electrode layer is left on the entire surface. Therefore, the increase in manufacturing cost does not occur substantially.

In FIG. 6A (d), as in the first embodiment, after the second insulating film 26 is formed, the opening 27 is formed by photolithography and etching. Next, after forming the wiring 28 and forming the protective film 29, the electrode terminal 30 is opened by photolithography and etching.

In FIG. 6B (e), the protective film 29 at the portion where the nozzle hole 14 is opened by photolithography and etching, the second insulating film 26, the first insulating film 21, and the diaphragm 20 are patterned.
The resist mask is common, for example, the protective film 29 which is a silicon nitride film, for example, the second insulating film 26 which is a silicon oxide film, for example, the first insulating film 21 which is a silicon oxide film has the same etching apparatus and the same conditions. The etching is performed continuously with. Specifically, etching is performed by RIE using _{CF 4} and CHF _3. Further, for example, the diaphragm 20 made of silicon is etched with a silicon deep-drill etcher while the resist mask remains in the state after etching the laminated film.

In FIG. 6 (f), the liquid chamber 12 is formed by etching the substrate 10 from the surface opposite to the surface on which the element is formed. In this way, the liquid discharge head of the present embodiment is obtained.

(Third embodiment)
The schematic diagram of the liquid discharge head of this embodiment is shown in FIGS. 7 to 9. FIG. 7 is a plan layout view of a main part of the present embodiment, FIG. 8 corresponds to a cross section taken along the line AA'in FIG. 7, and FIG. 9 corresponds to a cross section taken along the line BB'in FIG. Although the pattern design of the piezoelectric element, wiring, and the like in this embodiment is different, the layer structure is basically the same as that in the above embodiment. Descriptions of the same items as in the above embodiment will be omitted.

In this embodiment, as shown in FIGS. 8 and 9, a substrate 10, a sealing substrate 15 on which a liquid supply path 16 (also referred to as a supply path, an ink supply path, etc.) is formed, and a nozzle hole 14 are formed. Is formed by joining the nozzle plate 13 on which the above is formed with the adhesives 43a and 43b.

Examples of the substrate on which the piezoelectric element is formed include a substrate 10, a liquid chamber 12 formed in the substrate 10, a vibrating plate 20, a liquid supply path 16 formed through the vibrating plate 20, and the first insulating film 21. , 1st electrode layer 22, 1st piezoelectric 23, 2nd piezoelectric 24, 2nd electrode layer 25, 2nd insulating film 26, opening 27 of 2nd insulating layer 26, wiring 28, The protective film 29 and the electrode terminal 30 are shown in the figure.

Then, in FIG. 7, the separation groove 18, the first electrode layer 22, the first portion 25a, the second portion 25b, the first piezoelectric body 23, the second piezoelectric body 24, and the opening in the second electrode layer 25 are opened. The portion 27, the wiring 28, and the electrode terminal 30 are shown as a plan view.

Also in this embodiment, the first electrode layer 22 is a lower electrode of the piezoelectric element, and the first portion 25a in the second electrode layer 25 is an upper electrode of the piezoelectric element. Further, the second portion 25b in the second electrode layer 25 is formed in contact with the first electrode layer 22 and the piezoelectric body (second piezoelectric body 24), and is formed together with the first electrode layer 22 as a common electrode. It has become.

In the present embodiment, a driving voltage is applied between the upper electrode and the lower electrode to generate a driving force in the piezoelectric body (the first piezoelectric body 23 and the second piezoelectric body 24). By vibrating the diaphragm 20 thereby, the liquid in the liquid chamber 12 is pressurized and the liquid is discharged from the nozzle hole 14. The drive voltage is supplied from the outside via the electrode terminal 30 and the wiring 28. The upper electrode is an individual electrode for each nozzle, and the lower electrode is a common electrode for the entire head so that the liquid can be discharged individually for each nozzle. The actual number of nozzles is usually much larger than that shown in the figure.

As the sealing substrate 15, for example, a silicon substrate can be used, and the liquid supply path 16 and the voids 17 are formed by etching.
As the nozzle plate 13, for example, a stainless steel substrate can be used, and the nozzle hole 14 is formed by machining.

As the substrate 10, a single crystal silicon substrate is preferably used as in the above embodiment. Further, the diaphragm 20 can use single crystal silicon as in the above embodiment, and can be formed by using the SOI substrate manufacturing technique. In the present embodiment, as in the second embodiment, a normal SOI wafer in which no voids are formed is used.

Similar to the second embodiment, the liquid chamber 12 is formed by forming a piezoelectric element or the like and then etching a substrate 10 from a surface opposite to the element. The liquid is supplied to the liquid chamber 12 from the upper surface direction of FIG. 8 through the liquid supply path 16 of the sealing substrate 15.

In the present embodiment, for example, a substrate 10 having a thickness of about 625 μm is used, and as will be described later, the thickness of the substrate 10 is reduced to about 75 μm before processing. The dimensions of the liquid chamber 12 can be about 60 μm × about 1000 μm, and the depth can be about 75 μm. Further, the thickness of the diaphragm 20 can be about 2 μm. Further, the thermal oxide film (silicon oxide film 19) between the single crystal silicon layers can be about 0.5 μm.

The layer structure of the piezoelectric element on the diaphragm 20 is basically the same as that of the above embodiment.
Also in the present embodiment, the second electrode layer 25 is formed in contact with the first portion 25a formed only on the electromechanical conversion film, the first electrode layer 22 and the electromechanical conversion film, and is the first. It is composed of a second portion 25b formed separately from the portion 25a of the above.

The first portion 25a in the second electrode layer 25 is formed only on the electromechanical conversion film (on the second piezoelectric body 24), and is an upper electrode (individual electrode) of the piezoelectric element. The second portion 25b is formed from the top of the piezoelectric body to the portion without the piezoelectric body, is connected to the first electrode layer 22, and functions as a part of the common electrode of the piezoelectric element.

However, this embodiment differs from the above embodiment in the following points.
In the above embodiment, the second portion 25b in the second electrode layer 25 is arranged so as to cover the entire outer circumference of the piezoelectric body (first piezoelectric body 23, second piezoelectric body 24).
On the other hand, in the present embodiment, as shown in FIGS. 7 and 8, the piezoelectric material is arranged so as to cover only a part of the outer periphery thereof. Specifically, the second portion 25b in the second electrode layer 25 is arranged so as to cover only the direction of the connection portion between the common electrode and the wiring 28 in the piezoelectric body.

As shown in the figure, where the second portion 25b in the second electrode layer 25 does not cover the outer periphery of the piezoelectric body (the first piezoelectric body 23 and the second piezoelectric body 24), the outer peripheral shape of the piezoelectric body. And the outer peripheral shape of the first electrode layer 22 have the same shape. Where the second portion 25b covers the outer periphery of the piezoelectric body (the first piezoelectric body 23 and the second piezoelectric body 24), the outer peripheral shape of the second portion 25b and the outer peripheral shape of the first electrode layer 22. Has the same shape.

That is, in the present embodiment, the outer peripheral shape of the first electrode layer 22 is the same outer edge as the second portion 25b with respect to the portion of the second electrode layer 25 in contact with the second portion 25b, and the second portion. The portion not in contact with 25b has the same outer edge as the electromechanical conversion film. Therefore, the outer edge of the portion where the first electrode layer 22 and the second portion 25b are in contact is the same except for the portion where the second portion 25b is formed on the piezoelectric body. As a result, the wiring resistance of the lower electrode as the common electrode can be further reduced, so that an electromechanical conversion element having higher high frequency characteristics can be obtained.

In this embodiment, the resistance tends to be larger than that of the above-described embodiment in terms of the wiring resistance of the lower electrode (common electrode). Therefore, when the drive frequency is high, the above embodiment is preferable to the configuration according to the present embodiment.

On the other hand, since the area (width) of the upper electrode can be increased (widened) and the portion that hinders the displacement of the lower electrode can be removed, the displacement of the piezoelectric element can be increased as compared with the above embodiment. Therefore, depending on the drive frequency, it may be advantageous to have a configuration like the present embodiment because the displacement becomes large. For this reason, the liquid discharge head in the present embodiment has such a configuration because the drive frequency is affected not by the electrical characteristics but by the configuration of the liquid discharge and the liquid supply. The liquid discharge head of the present embodiment is driven at, for example, about 40 kHz.

Also in the present embodiment, as in the above embodiment, the arrangement region of the common electrode composed of the first electrode layer and the second portion in the second electrode layer is divided into the region where the piezoelectric element is formed and the wiring. It is limited to the connection area and the margin area required for processing so that the area is not wider than necessary. As a result, the parasitic capacitance between the upper electrode lead-out wiring and the common electrode (lower electrode) is reduced as compared with the case where the second portion of the first electrode layer and the second electrode layer is left on the entire surface without patterning. This makes it possible to improve the high frequency characteristics of the piezoelectric element and suppress power consumption.

Further, since the arrangement region of the common electrode is suppressed, the probability that the film peeling of the common electrode occurs can be reduced, and the yield can be improved. Further, although not shown in the present embodiment, the electrode material on the dicing street is removed, and it is possible to make a chip by laser dicing.

Further, in the present embodiment, since the common electrode around the liquid supply path 16 is also removed, it is not necessary to remove the common electrode material by etching when opening the liquid supply path 16. Therefore, the manufacturing process can be suppressed and the manufacturing cost can be suppressed without increasing the manufacturing process.

Further, in the present embodiment, since the common electrode layer is patterned and removed larger than the opening width of the liquid supply path 16, the discharged liquid does not come into contact with the common electrode on the side surface of the liquid supply path without adding a special step. Can be structured. Therefore, for example, even when a bias voltage is applied to the common electrode, it is possible to prevent the generation of a leak current to the discharge liquid side, the malfunction of the device due to it, the deterioration of the discharge liquid, etc. without adding a special process. Can be done.

Next, the manufacturing method of the electromechanical conversion element of the present embodiment will be described with reference to the manufacturing process flow of FIGS. 10 and 11. FIG. 10 corresponds to the AA'cross section of FIG. 7, and FIG. 11 corresponds to the BB'cross section of FIG.

In FIGS. 10A and 11A, the first insulating film 21, the first electrode layer 22, and the first piezoelectric material are formed on the substrate 10 on which the diaphragm 20 is formed, as in the above embodiment. 23 is formed into a film. In this embodiment, as in the second embodiment, an SOI substrate in which voids are not formed is used.

After that, the first piezoelectric body 23 is patterned into a desired shape by photolithography and etching, the second piezoelectric body 24 is formed only at a desired position by using inkjet technology, and the second electrode layer 25 is formed on the second piezoelectric body 24. Is formed into a film. Next, a resist mask (resist 40) having a pattern that can separate the second electrode layer 25 into the first portion 25a and the second portion 25b and remove the electrode layer in the excess region is formed.

In FIGS. 10A (b) and 11A (b), the second electrode layer 25 is etched using the resist 40 as a mask. As a result, the second electrode layer 25 is separated into a first portion 25a and a second portion 25b.

In FIGS. 10A (c) and 11A (c), etching is continuously performed from FIGS. 10A (b) and 11A (b), and the first electrode layer 22 is etched.
As in the first embodiment, the piezoelectric body (second piezoelectric body 24) is slightly etched to form the separation groove 18, but the separation groove 18 may not be present.

In the resist forming portion and the forming portion of the piezoelectric body (first piezoelectric body 23, second piezoelectric body 24) in the resist opening, the first electrode layer 22 remains without being removed by etching, and the other portion is the first. The electrode layer 22 of 1 is removed by etching. Therefore, the lower electrode (common electrode) is connected to the connection portion with the wiring 28 without being separated (FIG. 10A (c)), but the lower electrode layer between the adjacent nozzles is removed (FIG. 11A). (C)). Since such a pattern is used, the width of the first portion 25a in the second electrode layer 25, which is the upper electrode, can be maximized while ensuring a processing margin.

Further, here, for convenience, FIGS. 10A (b) and 10A (c) are divided into FIGS. 11A (b) and 11A (c), which are shown and described separately. It is continuously performed as substantially the same process. That is, the second electrode layer 25 is etched using a mask, and the first electrode layer 22 is continuously etched using the same mask, so that the first electrode layer 22 and the second portion 25b are formed. The outer edges of the contacting parts are made the same.
Therefore, the number of steps is not increased and the time of the steps is slightly longer than that of the conventional configuration in which the common electrode layer is left on the entire surface. Therefore, the increase in manufacturing cost does not occur substantially.

In FIGS. 10A (d) and 11A (d), the opening 27 is formed by photolithography and etching after forming the second insulating film 26 in the same manner as in the above embodiment. Next, after forming the wiring 28 and forming the protective film 29, the electrode terminal 30 is opened by photolithography and etching.

In FIGS. 10A and 11A, the protective film 29 of the liquid supply path 16 portion, the second insulating film 26, the first insulating film 21, the diaphragm 20, and the silicon oxide film are subjected to photolithography and etching. 19 is patterned. In these processes, the resist mask is common, for example, the protective film 29 which is a silicon nitride film, for example, the second insulating film 26 which is a silicon oxide film, for example, the insulating film 21 which is a silicon oxide film is the same etching apparatus. Etching is performed continuously under the same conditions. Specifically, etching is performed by RIE using _{CF 4} and CHF _3.
Further, for example, the diaphragm 20 made of silicon is etched with a silicon deep-drill etcher while the resist mask remains in the state after etching the laminated film. Further, the silicon oxide film 19 is etched by RIE using _{CF 4} and CHF _3.

In FIGS. 10B (f) and 11B (f), the sealing substrate 15 in which the liquid supply path 16 and the void 17 (piezoelectric element vibration space) are formed, which are prepared in advance, is the substrate 10 on which the piezoelectric element is formed. Join with adhesive 43b on top.

In FIGS. 10B (g) and 11B (g), first, the substrate 10 is thinned from 625 μm to 75 μm in a state of being bonded to the sealed substrate 15 (not shown). Next, the liquid chamber 12 is formed by photolithography and etching. Etching is performed at Silicon Fukahori Etcher. Then, if necessary, a wetted film (liquid resistant protective film) is formed and chipped by laser dicing.

In FIGS. 10B (h) and 11B (h), the nozzle plate 13 having the nozzle hole 14 opened is joined with the adhesive 43a in advance. In this way, the liquid discharge head of the present embodiment is obtained.

(Liquid discharge unit, device that discharges liquid)
Next, an example of the device for discharging the liquid according to the present invention will be described with reference to FIGS. 12 and 13. FIG. 12 is an explanatory plan view of a main part of the device, and FIG. 13 is an explanatory view of a side surface of the main part of the device.

This device is a serial type device, and the carriage 403 is reciprocated in the main scanning direction by the main scanning moving mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, and the like. The guide member 401 is bridged over the left and right side plates 491A and 491B to movably hold the carriage 403. Then, the carriage 403 is reciprocated in the main scanning direction by the main scanning motor 405 via the timing belt 408 bridged between the drive pulley 406 and the driven pulley 407.

The carriage 403 is equipped with a liquid discharge unit 440 in which the liquid discharge head 404 and the head tank 441 according to the present invention are integrated. The liquid discharge head 404 of the liquid discharge unit 440 discharges, for example, liquids of each color of yellow (Y), cyan (C), magenta (M), and black (K). Further, the liquid discharge head 404 has a nozzle row composed of a plurality of nozzles 11 arranged in a sub-scanning direction orthogonal to the main scanning direction, and is mounted with the discharge direction facing downward.

The liquid stored in the liquid cartridge 450 is supplied to the head tank 441 by the supply mechanism 494 for supplying the liquid stored outside the liquid discharge head 404 to the liquid discharge head 404.

The supply mechanism 494 includes a cartridge holder 451 which is a filling part for mounting the liquid cartridge 450, a tube 456, a liquid feeding unit 452 including a liquid feeding pump, and the like. The liquid cartridge 450 is detachably attached to the cartridge holder 451. Liquid is delivered from the liquid cartridge 450 to the head tank 441 by the liquid feeding unit 452 via the tube 456.

This device includes a transport mechanism 495 for transporting the paper 410. The transport mechanism 495 includes a transport belt 412, which is a transport means, and a sub-scanning motor 416 for driving the transport belt 412.

The transport belt 412 attracts the paper 410 and transports it at a position facing the liquid discharge head 404. The transport belt 412 is an endless belt, and is hung between the transport roller 413 and the tension roller 414. Adsorption can be performed by electrostatic adsorption, air suction, or the like.

Then, the transport belt 412 orbits in the sub-scanning direction by rotationally driving the transport roller 413 via the timing belt 417 and the timing pulley 418 by the sub-scanning motor 416.

Further, on one side of the carriage 403 in the main scanning direction, a maintenance / recovery mechanism 420 for maintaining / recovering the liquid discharge head 404 is arranged on the side of the transport belt 412.

The maintenance / recovery mechanism 420 includes, for example, a cap member 421 that caps the nozzle surface (the surface on which the nozzle 11 is formed) of the liquid discharge head 404, a wiper member 422 that wipes the nozzle surface, and the like.

The main scanning movement mechanism 493, the supply mechanism 494, the maintenance / recovery mechanism 420, and the transport mechanism 495 are attached to a housing including the side plates 491A and 491B and the back plate 491C.

In this apparatus configured in this way, the paper 410 is fed onto the transport belt 412 and sucked, and the paper 410 is conveyed in the sub-scanning direction by the circumferential movement of the conveyor belt 412.

Therefore, by driving the liquid ejection head 404 in response to the image signal while moving the carriage 403 in the main scanning direction, the liquid is ejected onto the stopped paper 410 to form an image.

As described above, since this device includes the liquid discharge head according to the present invention, it is possible to stably form a high-quality image.

Next, another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 14 is an explanatory plan view of a main part of the unit.

This liquid discharge unit includes a housing portion composed of side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid among the members constituting the device for discharging the liquid. It is composed of a discharge head 404.

It should be noted that a liquid discharge unit may be configured in which at least one of the above-mentioned maintenance / recovery mechanism 420 and the supply mechanism 494 is further attached to, for example, the side plate 491B of the liquid discharge unit.

Next, still another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 15 is a front explanatory view of the unit.

This liquid discharge unit includes a liquid discharge head 404 to which the flow path component 444 is attached, and a tube 456 connected to the flow path component 444.

The flow path component 444 is arranged inside the cover 442. A head tank 441 may be included instead of the flow path component 444. Further, a connector 443 that electrically connects to the liquid discharge head 404 is provided on the upper part of the flow path component 444.

In the present application, the "device for discharging a liquid" is a device provided with a liquid discharge head or a liquid discharge unit and driving the liquid discharge head to discharge the liquid. The device for discharging a liquid includes not only a device capable of discharging a liquid to a device to which the liquid can adhere, but also a device for discharging the liquid into the air or into the liquid.

The "device for discharging the liquid" can also include means for feeding, transporting, and discharging paper to which the liquid can adhere, as well as a pretreatment device, a posttreatment device, and the like.

For example, as a "device that ejects a liquid", an image forming device that is a device that ejects ink to form an image on paper, and a three-dimensional object (three-dimensional object) are formed in layers in order to form a three-dimensional object. There is a three-dimensional modeling device (three-dimensional modeling device) that discharges the modeling liquid into the powder layer.

Further, the "device for discharging a liquid" is not limited to a device in which a significant image such as characters and figures is visualized by the discharged liquid. For example, those that form patterns that have no meaning in themselves and those that form a three-dimensional image are also included.

The above-mentioned "thing to which a liquid can adhere" means a material to which a liquid can adhere at least temporarily, such as a material to which the liquid adheres and adheres, and a material to which the liquid adheres and permeates. Specific examples include paper, recording paper, recording paper, film, recorded media such as cloth, electronic substrates, electronic components such as piezoelectric elements, powder layers (powder layers), organ models, and media such as inspection cells. Yes, and includes everything to which the liquid adheres, unless otherwise specified.

The above "materials to which liquid can adhere" are temporary liquids such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and flooring, and textiles for clothing. But it is good if it can be attached.

The "liquid" also includes inks, treatment liquids, DNA samples, resists, pattern materials, binders, modeling liquids, or solutions and dispersions containing amino acids, proteins, and calcium.

Further, the "device for discharging the liquid" includes, but is not limited to, a device in which the liquid discharge head and the device to which the liquid can adhere move relatively. Specific examples include a serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like.

In addition, as a "device for ejecting liquid", a treatment liquid coating device for ejecting a treatment liquid to the paper in order to apply the treatment liquid to the surface of the paper for the purpose of modifying the surface of the paper, raw materials. There is an injection granulation device that granulates fine particles of raw materials by injecting a composition liquid dispersed in a solution through a nozzle.

The "liquid discharge unit" is a liquid discharge head integrated with functional parts and a mechanism, and is a collection of parts related to liquid discharge. For example, the "liquid discharge unit" includes a head tank, a carriage, a supply mechanism, a maintenance / recovery mechanism, a main scanning movement mechanism in which at least one of the configurations is combined with a liquid discharge head, and the like.

Here, the term "integration" means, for example, a liquid discharge head and a functional component, a mechanism in which the mechanism is fixed to each other by fastening, bonding, engagement, etc., or one in which one is movably held with respect to the other. include. Further, the liquid discharge head, the functional component, and the mechanism may be configured to be detachable from each other.

For example, as a liquid discharge unit, there is a liquid discharge head and a head tank integrated, such as the liquid discharge unit 440 shown in FIG. In some cases, the liquid discharge head and the head tank are integrated by being connected to each other by a tube or the like. Here, a unit including a filter can be added between the head tank of these liquid discharge units and the liquid discharge head.

Further, as a liquid discharge unit, there is a unit in which a liquid discharge head and a carriage are integrated.

Further, there is a liquid discharge unit in which the liquid discharge head and the scanning movement mechanism are integrated by holding the liquid discharge head movably by a guide member constituting a part of the scanning movement mechanism. Further, as shown in FIG. 14, there is a liquid discharge unit in which a liquid discharge head, a carriage, and a main scanning movement mechanism are integrated.

Further, as a liquid discharge unit, there is a carriage to which a liquid discharge head is attached, in which a cap member which is a part of the maintenance / recovery mechanism is fixed, and the liquid discharge head, the carriage, and the maintenance / recovery mechanism are integrated. ..

Further, as a liquid discharge unit, as shown in FIG. 15, a tube is connected to a head tank or a liquid discharge head to which a flow path component is attached, and the liquid discharge head and a supply mechanism are integrated. ..

The main scanning movement mechanism shall include a single guide member. Further, the supply mechanism includes a single tube and a single loading unit.

Further, the pressure generating means used for the "liquid discharge head" is not limited. For example, in addition to the piezoelectric actuator (which may use a laminated piezoelectric element) as described in the above embodiment, it is composed of a thermal actuator using an electric heat conversion element such as a heat generating resistor, a vibrating plate, and a counter electrode. An electrostatic actuator or the like may be used.

Further, in the terms of the present application, image formation, recording, printing, printing, printing, modeling, etc. are all synonymous.

10 Substrate 11 Void 12 Liquid chamber 13 Nozzle plate 14 Nozzle hole 15 Sealed substrate 16 Liquid supply path 17 Void 18 Separation groove 19 Silicon oxide film 20 Vibration plate 21 First insulating film 22 First electrode layer 23 First piezoelectric Body 24 Second Piezoelectric Body 25 Second Electrode Layer 25a First Part 25b Second Part 26 Second Insulation Film 27 Opening 28 Wiring 29 Protective Film 30 Electrode Terminals 43a, 43b Adhesive 401 Guide Member 403 Carriage 404 Liquid discharge head 405 Main scanning motor 406 Drive pulley 407 Driven pulley 408 Timing belt 410 Paper 412 Conveying belt 413 Conveying roller 414 Tension roller 416 Sub-scanning motor 417 Timing belt 418 Timing pulley 420 Maintenance recovery mechanism 421 Cap member 422 Discharge unit 441 Head tank 442 Cover 443 Connector 444 Flow path parts 450 Liquid cartridge 451 Cartridge holder 452 Liquid transfer unit 456 Tube 491A, 491B Side plate 491C Back plate 493 Main scanning movement mechanism 494 Supply mechanism 495 Transport mechanism

Japanese Unexamined Patent Publication No. 2013-06670 Japanese Unexamined Patent Publication No. 2016-58715 Japanese Unexamined Patent Publication No. 2014-101356

Claims (10)

The first electrode layer formed on the substrate and
The electromechanical conversion film formed on the first electrode layer and
An electromechanical conversion element having a second electrode layer formed on the first electrode layer and the electromechanical conversion film.
The first electrode layer is formed on a part of the substrate and is formed.
The second electrode layer is formed in contact with a first portion formed only on the electromechanical conversion film and on the first electrode layer and the electromechanical conversion film, and the first portion is formed. It consists of a second part formed separately from
An electromechanical conversion element characterized in that the outer edge of a portion in contact with the first electrode layer and the second portion located outside the end portion of the substrate is the same. A separation groove is formed in the electromechanical conversion membrane, and the separation groove is formed.
The electromechanical conversion element according to claim 1, wherein the first portion and the second portion are separated by a separation groove as a boundary. A claim characterized in that the first electrode layer and the second electrode layer have the same area when viewed from a direction perpendicular to the surface direction of the electromechanical conversion element, except for the separation groove. Item 2. The electromechanical conversion element according to Item 2. When viewed from a direction perpendicular to the surface direction of the electromechanical conversion element, the electromechanical conversion film and the first portion are formed in an annular shape, and the first electrode layer and the said first portion inside the annular shape. The electromechanical conversion element according to any one of claims 1 to 3, wherein the area of the second portion is the same. The second portion is formed so as to cover a part of the outer periphery of the electromechanical conversion film.
The outer peripheral shape of the first electrode layer has the same outer edge as the second portion for the portion in contact with the second portion, and the same as the electromechanical conversion film for the portion not in contact with the second portion. The electromechanical conversion element according to claim 1 or 2, characterized in that it is an outer edge. A liquid discharge head comprising the electromechanical conversion element according to any one of claims 1 to 5. A liquid discharge unit comprising the liquid discharge head according to claim 6. A device for discharging a liquid, which comprises the liquid discharge head according to claim 6 or the liquid discharge unit according to claim 7. An ultrasonic wave generator comprising the electromechanical conversion element according to any one of claims 1 to 5. The process of forming the first electrode layer on the substrate and
The step of forming an electromechanical conversion film on the first electrode layer and
The step of forming the second electrode layer on the first electrode layer and the electromechanical conversion film, and
The second electrode layer is etched and formed in contact with the first portion formed only on the electromechanical conversion film and on the first electrode layer and the electromechanical conversion film. A method for manufacturing an electromechanical conversion element having a step of separating into two parts.
In the separation step, the second electrode layer is etched with a mask, and the first electrode layer is continuously etched with the same mask, and the second portion is the electric machine. A method for manufacturing an electromechanical conversion element, wherein the outer edge of a portion in contact with the first electrode layer and the second portion is the same except for a portion formed on the conversion film.

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