JP2006100814A - Piezoelectric/electrostrictive element structure, method of manufacturing piezoelectric/electrostrictive element structure, and method of manufacturing liquid jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an element which allows microfabrication generally used in a semiconductor process and area enlargement and is excellent in durability and ferroelectric properties, and a manufacturing method thereof; a piezoelectric element structure which is excellent in durability and piezoelectric property that is one of the ferroelectric properties; and a liquid jet head which has a long, high-density liquid jet nozzle and is stable and highly reliable, and a manufacturing method thereof. <P>SOLUTION: A piezoelectric/electrostrictive element structure comprises a buffer layer which is formed by being oriented-grown on a monocrystal substrate; a lower electrode layer which is formed by being oriented-grown on the buffer layer; a piezoelectric/electrostrictive layer which is formed by being oriented-grown on the lower electrode layer; and an upper electrode layer which is formed on the piezoelectric/electrostrictive layer. The buffer layer is patterned, and the piezoelectric/electrostrictive layer is patterned according to the pattern of the buffer layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor storage device such as a nonvolatile memory using a thin film having material characteristics such as piezoelectricity, pyroelectricity, and ferroelectricity, a piezoelectric element, an ultrasonic application element, an electro-optic element, a pyroelectric element, The present invention relates to a piezoelectric / electrostrictive element structure that can be applied to a dielectric element or the like and a manufacturing method thereof, and more particularly to a manufacturing method of a liquid jet head using a piezoelectric / electrostrictive material.

  Piezoelectric / electrical materials using piezoelectric, pyroelectric or ferroelectric materials such as semiconductor memory devices such as non-volatile memory, surface acoustic wave elements, bulk ultrasonic elements, acceleration sensors, piezoelectric actuators or pyroelectric infrared sensing elements The strained element structure has been conventionally produced by pasting a machined single crystal substrate or polycrystalline sintered body on a substrate. In recent years, attempts have been made to use single crystal materials to reduce the size, increase the density, reduce the weight, and increase the functionality of devices. Many researches and developments have been made to form films of these single crystal materials on top of them and make them into devices. For example, thin film piezoelectric elements such as thin film vibrators and piezoelectric actuators used as key components in information communication equipment and televisions are composed of a piezoelectric body and a plurality of electrodes provided on the piezoelectric body. It is a device that converts this electrical energy into mechanical energy when applied. In the mobile communication market, surface acoustic wave (SAW) devices, thin film bulk acoustic resonators (FBAR), and the like are used as RF and IF filters.

  In recent years, printers using a liquid jet recording apparatus as an output device such as a personal computer have become widespread for reasons such as good printing performance, easy handling and low cost. In this liquid jet recording apparatus, bubbles are generated in a liquid such as ink by thermal energy, droplets are ejected by pressure waves caused by the bubbles, droplets are sucked and ejected by electrostatic force, piezoelectric / electrostrictive There are various methods such as those using pressure waves generated by vibrators such as elements.

  In general, a liquid ejecting apparatus using a piezoelectric / electrostrictive element (hereinafter referred to as a liquid ejecting head) includes, for example, a pressure chamber that communicates with a liquid supply chamber and a liquid discharge port that communicates with the pressure chamber. A vibration plate to which a piezoelectric / electrostrictive element is bonded is provided. By applying a predetermined voltage to the piezoelectric / electrostrictive element and expanding / contracting the piezoelectric / electrostrictive element, the vibration is caused to bend and the liquid in the pressure chamber is compressed and a droplet is discharged from the liquid discharge port. Let

  In recent years, there has been a demand for improved printing performance, especially higher resolution and higher speed printing, and longer liquid jet heads. High resolution and high speed printing have been realized using a multi-nozzle head structure with a finer liquid jet head. It has been tried to do. In order to miniaturize the liquid ejecting head, it is necessary to reduce the size, density, and performance of the piezoelectric / electrostrictive element for ejecting the liquid. For example, to increase the length, the liquid ejecting head It is necessary to increase the area of the substrate for manufacturing the substrate.

  In the actuator and liquid ejecting head that are the piezoelectric / electrostrictive element structure as described above, in order to reduce the size and increase the density of the element, a high piezoelectric that does not decrease the effective driving ability even if the element is reduced in size. / It needs to have electrostrictive characteristics. One way to do this is to increase the crystallinity of the piezoelectric / electrostrictive thin film. These include single-oriented thin films oriented in the same direction and single-crystal thin films aligned in-plane. . In order to fabricate such a single-orientation or single-crystal piezoelectric / electrostrictive thin film, the layer immediately below the piezoelectric / electrostrictive thin film is a single crystal, and the piezoelectric / electrostrictive thin film The lattice matching with the layer needs to be good.

  The definition of such a single alignment film means a crystallized film in which target crystal planes are aligned in parallel with the substrate surface as described in Japanese Patent Application Laid-Open No. 2000-332569. For example, a (001) single orientation film means a film having a (001) plane almost parallel to the film surface. Specifically, when measurement is performed by X-ray diffraction, A film having a reflection peak intensity of 10% or less, preferably 5% or less of the maximum peak intensity of the target surface.

  Further, in this specification, the single crystal film includes a single-oriented epitaxial film, which is a single-oriented film, and the inside of the film is an XY plane, and the film thickness direction is a Z-axis. In this case, the crystals are aligned along the X-axis, Y-axis, and Z-axis directions. Specifically, when measurement is performed by X-ray diffraction, the peak intensity of reflection from objects other than the target surface needs to be 10% or less, preferably 5% or less of the maximum peak intensity of the target surface. . In the present invention, a crystal having high orientation means a crystal having a specific orientation of a specific crystal structure of 50% or more by X-ray diffraction, and further 80% or more, more preferably 99% or more. It is.

For example, as a material having a good lattice matching between the PZT piezoelectric thin film and the layer immediately below, a buffer layer including ZrO2, a stabilized zirconia thin film, a rare earth element oxide thin film (YSZ) described in JP 2000-332569 A, etc. There are proposals and proposals using SRO, which can also be used as an electrode material, as a buffer layer, as described in JP-A-6-280023.
JP 2000-332569 A JP-A-6-280023

  When a YSZ as a buffer layer, Pt as a lower electrode, and a PZT film as an upper piezoelectric / electrostrictive layer are oriented and stacked on a large-area Si single crystal substrate such as a 6-inch wafer, each layer including the substrate A great amount of stress is applied to the interface of the substrate, and there may occur a problem that the substrate including the laminated film is warped, and further peeled off from any interface of the laminated film. The stress at the interface between the laminated films tends to increase as the crystallinity of the PZT alignment film improves, and it can be said that the improvement in film performance by increasing the area and improving the crystallinity has a trade-off. It will also hinder the transformation.

  Furthermore, when the oriented piezoelectric / electrostrictive film or single crystal piezoelectric / electrostrictive film formed in this way is structured by etching for device formation, the above laminated structure has a polycrystalline structure. There is a problem that the etching rate is lower than the piezoelectric / electrostrictive film and the workability is sometimes poor. This problem also causes secondary adverse effects such as shape changes and film performance deterioration during device processing, and leaves further problems for microfabrication. Furthermore, when such a highly crystalline piezoelectric / electrostrictive film is processed and driven as an actuator such as a liquid jet head, it is peeled off from any interface of the piezoelectric / electrostrictive film, electrode, buffer material, and substrate. There is a problem in the stability of discharge and durability as an apparatus. As described above, these are considered to be generated based on the stress accumulated during the formation of each of the laminated films.

  An object of the present invention is to provide a single-crystal layer on a single-crystal substrate in a single-crystal oxide layer on a single-crystal substrate applied to a piezoelectric / electrostrictive element structure such as a semiconductor device or a piezoelectric actuator. To solve the problem that the layer configuration cannot be simplified due to the influence of stress or the like at the interface with a crystal substrate, etc., and to provide a method for manufacturing a structure such as a device on a single crystal substrate with a simple configuration .

  A further object of the present invention has been made in view of the above-mentioned unsolved problems, and is capable of microfabrication and large area generally used in semiconductor processes, and has improved durability and piezoelectric / electrostrictive characteristics. An object of the present invention is to provide an excellent device and a manufacturing method thereof.

  A further object of the present invention is to have a piezoelectric / electrostrictive element structure excellent in piezoelectric properties, which is one of durability and ferroelectric properties, and a long and high-density liquid discharge port, An object of the present invention is to provide a method for manufacturing a liquid jet head that is stable and highly reliable.

A first aspect of the method for manufacturing a piezoelectric / electrostrictive element structure according to the present invention is a piezoelectric / electrostrictive having a piezoelectric / electrostrictive film, a lower electrode and an upper electrode sandwiching the piezoelectric / electrostrictive film. A method for manufacturing a body element structure,
Forming a buffer layer oriented and grown in a pattern on a single crystal substrate;
Aligning and growing the lower electrode layer on the buffer layer;
A step of orientationally growing the piezoelectric / electrostrictive film so as to cover the buffer layer and the lower electrode layer;
Removing a portion of the piezoelectric / electrostrictive film other than the portion grown by orientation following the pattern of the buffer layer by an etching process;
A method for manufacturing a piezoelectric / electrostrictive element structure, comprising:

  A first aspect of the piezoelectric / electrostrictive element structure of the present invention is a piezoelectric / electrostrictive element structure manufactured by the first aspect of the method for manufacturing a piezoelectric / electrostrictive element structure described above. .

According to a second aspect of the method for manufacturing a piezoelectric / electrostrictive element structure of the present invention, a piezoelectric / electrostrictive film having a piezoelectric / electrostrictive film, a lower electrode and an upper electrode sandwiching the piezoelectric / electrostrictive film is provided. A method for manufacturing a body element structure,
Forming a buffer layer oriented and grown on a single crystal substrate;
Forming the lower electrode layer oriented and grown in a pattern on the buffer layer;
A step of orientationally growing the piezoelectric / electrostrictive film so as to cover the buffer layer and the lower electrode layer;
Removing a portion of the piezoelectric / electrostrictive film other than the portion grown by orientation following the pattern of the lower electrode layer by an etching process;
A method for manufacturing a piezoelectric / electrostrictive element structure, comprising:

  A second aspect of the piezoelectric / electrostrictive element structure according to the present invention is a piezoelectric / electrostrictive element structure manufactured by the second aspect of the method for manufacturing a piezoelectric / electrostrictive element structure described above. .

According to a first aspect of the method of manufacturing a liquid jet recording head of the present invention, a liquid chamber communicating with a discharge port for discharging a liquid, a piezoelectric / electrostrictive film and the piezoelectric / electrostrictive film provided corresponding to the liquid chamber are provided. A piezoelectric / electrostrictive element structure having a lower electrode and an upper electrode sandwiching an electrostrictive film, and a method of manufacturing a liquid jet head comprising:
Forming a buffer layer oriented and grown in a pattern on a single crystal substrate;
Aligning and growing the lower electrode layer on the buffer layer;
A step of orientationally growing the piezoelectric / electrostrictive film so as to cover the buffer layer and the lower electrode layer;
Removing a portion of the piezoelectric / electrostrictive film other than the portion grown by orientation following the pattern of the buffer layer by an etching process;
A method for manufacturing a liquid jet head, comprising:

The second aspect of the liquid jet recording head of the present invention is:
A piezoelectric / electrostrictive film provided in correspondence with the liquid chamber, the piezoelectric / electrostrictive film, and a lower electrode and an upper electrode sandwiching the piezoelectric / electrostrictive film; An electrostrictive element structure, and a manufacturing method of a liquid jet head comprising:
Forming a buffer layer oriented and grown on a single crystal substrate;
Forming the lower electrode layer oriented and grown in a pattern on the buffer layer;
A step of orientationally growing the piezoelectric / electrostrictive film so as to cover the buffer layer and the lower electrode layer;
Removing a portion of the piezoelectric / electrostrictive film other than the portion grown by orientation following the pattern of the lower electrode layer by an etching process;
A method for manufacturing a liquid jet head, comprising:

According to the present invention, the following effects can be obtained.
(1) Since the stress can be dispersed more than when the buffer layer, the lower electrode layer and the piezoelectric / electrostrictive layer are formed only by epitaxial film formation or orientation film formation on a large-area single crystal substrate, the substrate warp or film peeling occurs. Can be prevented.
(2) The etching rate of the piezoelectric / electrostrictive thin film can be increased, and the processing shape and the like of the etched portion can be equalized and fine processing can be performed.

  In this specification, “epitaxial growth” means crystal growth that is oriented not only with respect to the uniaxial direction but also with respect to the plane direction.

  In order to form a piezoelectric / electrostrictive thin film such as PZT oriented or epitaxially grown on a 6-inch Si single crystal substrate having a large area, for example, the present inventors, As a material having good lattice matching, a conventionally known buffer material, electrode material, and the like have been repeatedly studied, but a complete solution for the above-mentioned problem has not been found. Therefore, in order to solve the problem of peeling at the interface of the laminated film accompanying the increase in area, a pattern of 100 μm □ as shown in FIG. 5A is formed on the (111) single crystal Si substrate in the sputtering apparatus. After contacting the metal mask, the substrate temperature was set to 800 ° C., and (111) -oriented 100 nm-thickness YSZ was used as a buffer layer for orientation film formation. Subsequently, the metal mask was removed, and then the substrate temperature was set to 600 ° C., and a (100) -oriented 100-nm-thick Pt electrode was continuously formed on the patterned buffer layer. Subsequently, when the substrate temperature was set to 650 ° C. and PZT was grown to a thickness of (100) with a thickness of 3000 nm, a film was formed on a large area without peeling as expected. When these crystallinity evaluations were performed by XRD (ATX-G: manufactured by Rigaku Corporation) in-plane measurement and out-of-plane measurement, the Pt electrode and the PZT film on the portion where the buffer layer was patterned were respectively A (100), (001) orientation degree is a crystal with high orientation of 90%, and a Pt electrode and a PZT film directly formed on a Si substrate without a buffer layer are (100), The (001) orientation degree was 50% or less. Since the Pt electrode and PZT film formed directly on the Si substrate on which the buffer layer is not formed have low orientation, the stress at the interface with each of the Si substrate, Pt electrode and PZT film is reduced, and the entire substrate In other words, it is considered that the stress was dispersed, and as a result, film formation on a large area became possible. In order to disperse stress due to the formation of a thin film on such a large-area substrate, it is more preferable that the buffer layer portion to be patterned is uniformly dispersed with respect to the substrate.

  Next, the metal mask described above was again brought into contact with the formed PZT film, and an electrode on Pt having a thickness of 100 nm was formed so as to face the patterned buffer layer. As a PZT etchant, water: concentrated nitric acid was used to evaluate the highly oriented PZT (X-ray diffraction (001) degree of orientation 90%) formed on the buffer layer of the laminated film thus obtained. : Wet etching was performed on a portion having low crystallinity using a mixed solution of concentrated hydrochloric acid = 2: 2: 1 (volume ratio), and it was found that etching was possible at an etching rate of 6 to 7 nm / min.

  During the study by the present inventors, the etching rate of highly oriented PZT formed on the buffer layer is as low as 3 to 4 nm / min, and at least the buffer layer is patterned with a PZT film having different crystallinity on the substrate. This makes it possible to dramatically improve the etching rate of the parts that are not necessary when forming the structure, greatly shorten the etching time, and the shape of the structure after etching is perpendicular to the substrate surface. It was possible to be close to.

  From this, stress relaxation at the interface of the above-mentioned laminated film can be achieved by simply creating a pattern with different crystallinity of piezoelectric / electrostrictive body such as PZT formed by orientation on the buffer layer. It became clear that it is an effective means to greatly increase the area and efficiency with respect to the structure as well as the effect.

  Here, the larger the difference in the degree of orientation between the portion with high crystallinity formed on the buffer layer and the portion with low crystallinity removed by etching without being used as a structure, the more preferable for etching. Similarly, in order to solve the problem of peeling at the interface of the laminated film due to the increase in area, a pattern of 100 μm □ as shown in FIG. 5B is formed on the (111) single crystal Si substrate in the sputtering apparatus. After forming the mask pattern, a Ti layer having a thickness of 50 nm was formed as an orientation blocking layer at room temperature. Subsequently, after removing the mask, the substrate temperature is set to 800 ° C., and a 100 nm thick YSZ film is formed as a buffer layer so as to cover the patterned Ti layer. At this time, a (111) -oriented YSZ layer is formed on the surface of the Si substrate without the Ti layer. Next, a substrate temperature was set to 600 ° C., and a 100 nm-thick Pt electrode having a (100) orientation was continuously formed on the buffer layer. Subsequently, when the substrate temperature was set to 650 ° C. and PZT was grown to a thickness of (001) with a thickness of 3000 nm, a film was formed on a large area without peeling as expected. When the crystallinity was evaluated by the above-described method, the degree of orientation of (100) and (001) was 50% or less on the Pt electrode and the PZT film, respectively, on the Ti layer patterned as the orientation blocking layer. In other places, the buffer layer, the Pt electrode, and the PZT film were highly oriented crystals. As a result, the buffer layer, the Pt electrode, and the PZT film on the portion where the alignment blocking layer is formed have low crystallinity, so that the stress at the interface with each of the Si substrate, the buffer layer, the Pt electrode, and the PZT film is reduced, and the entire substrate In other words, it is considered that the stress was dispersed, and as a result, film formation on a large area became possible. In order to disperse stress due to the formation of a thin film on such a large-area substrate, it is more preferable that the alignment blocking layer portion to be patterned is uniformly dispersed with respect to the substrate.

  Next, the above-described metal mask was brought into contact with the formed PZT film, and an upper Pt electrode having a thickness of 100 nm was formed so as to face a portion without the patterned alignment blocking layer. In order to evaluate a single PZT film having a high orientation of the laminated film thus obtained (X-ray diffraction has a (001) degree of orientation of 90%) as a PZT etching solution, water: concentrated nitric acid: concentrated hydrochloric acid = 2: When a portion having low crystallinity of PZT was wet-etched using a 2: 1 (volume ratio) mixed solution, it was found that etching was possible at an etching rate of 8 to 9 nm / min. During the study by the present inventors, the etching rate of PZT with high orientation formed on the buffer layer (90 degree of (001) orientation by X-ray diffraction) is as low as 3-4 nm / min. In addition, by forming PZT films with different crystallinity by patterning at least the orientation-blocking layer, the etching rate of the portions that are not necessary for the structure can be greatly improved, and the etching time can be greatly shortened. Also, the shape of the structure after the etching could be almost perpendicular to the substrate surface.

  As a result, the stress relaxation effect at the interface of the laminated film described above can be easily made by easily creating a pattern with different crystallinity of a piezoelectric / electrostrictive body such as PZT formed by orientation on the orientation blocking layer. At the same time, it has been found that this is an effective means for significantly increasing the area and efficiency of the structure. Next, in order to solve the problem of peeling at the laminated film interface due to the increase in area, the substrate temperature of the (111) single crystal Si substrate is set to 800 ° C. in the sputtering apparatus, and (111) oriented 100 nm thick YSZ is formed. An alignment film was formed as a buffer layer. Subsequently, a metal mask having a 100 μm square pattern as shown in FIG. 5A was contacted, and a substrate temperature was set to 600 ° C. to form a (100) -oriented 100 nm-thick Pt electrode pattern. Subsequently, after removing the metal mask, when the substrate temperature was set to 650 ° C. and PZT was formed thereon with a thickness of 3000 nm, peeling of the film was observed. When the crystallinity was evaluated as described above, the PZT film on the patterned Pt electrode layer was directly formed on the buffer layer in which the (001) orientation degree was 90% and the Pt electrode layer was not formed. The (001) orientation degree of the PZT film was worse than 92%. This is presumably because the lattice matching between the YSZ buffer layer and the PZT layer is better than the lattice matching between the Pt layer and the PZT layer oriented on the YSZ buffer layer. For this reason, both the PZT film directly formed on the buffer layer and the PZT film on the Pt electrode layer have high crystallinity, the stress at each interface becomes high, and the stress does not disperse even in the whole substrate, and the film peels off. It is thought that it occurred. Further, the above-described metal mask was brought into contact with the formed PZT film again, and the Pt upper electrode was formed with a thickness of 100 nm so as to face the patterned Pt electrode layer. In order to evaluate the oriented PZT film formed on the Pt electrode layer of the laminated film thus obtained and the PZT film directly oriented on the buffer layer, water: concentrated nitric acid: concentrated hydrochloric acid = 2: 2 as an etching solution for PZT. When a portion of PZT formed on the buffer layer was wet-etched using a mixed solution of 1 (volume ratio), it was found that etching could be performed at an etching rate of 3 to 4 nm / min.

  According to the study by the present inventors, the etching rate of PZT formed on the Pt electrode layer is 3 to 4 nm / min, which is the same as that on the buffer layer, and there is no difference in the etching rate. Therefore, in the sputtering apparatus, the substrate temperature of the (111) single crystal Si substrate was set to 800 ° C., and (111) oriented 100 nm thick YSZ was used as the buffer layer for orientation film formation. Subsequently, after contacting a metal mask having a 100 μm square pattern as shown in FIG. 5A, the substrate temperature was set to 600 ° C., and the (100) -oriented 100 nm-thick perovskite oxide conductive material SRO electrode. After forming the pattern and removing the metal mask as described above, the substrate temperature was set to 650 ° C., and PZT was formed thereon to a thickness of 3000 nm. When the Pt electrode as described above was used, film peeling occurred. I was able to reduce it. When the crystallinity was evaluated, the orientation of the PZT film on the portion where the SRO electrode layer was patterned was found to be (001) with a degree of orientation of 94% directly on the buffer layer where the SRO electrode layer was not formed. The (001) orientation degree of the deposited PZT film was better than 92%. In these, the lattice matching between the YSZ buffer layer and the PZT layer is further improved by interposing the SRO layer, and the SRO layer relaxes the stress at the interface with the PZT film and disperses the stress when viewed from the entire substrate. This is probably because the film peeling was reduced. In order to disperse stress due to the formation of a thin film on such a large-area substrate, the electrode layer portion made of a perovskite oxide conductive material such as SRO to be patterned is uniformly dispersed over a wide area. More preferably, it is arranged. Next, the above-described metal mask was again brought into contact with the formed PZT film, and an upper Pt electrode having a thickness of 100 nm was formed so as to face the patterned SRO electrode layer. In order to evaluate the single PZT film formed on the SRO electrode layer of the laminated film thus completed, a mixed solution of water: concentrated nitric acid: concentrated hydrochloric acid = 2: 2: 1 (capacity ratio) was used as an etching solution for PZT. When the portion having low crystallinity was wet-etched using the etching method, it was etched at an etching rate of 3 to 4 nm / min, which was almost the same as the etching rate of PZT formed on the SRO electrode layer. However, since PZT films with different crystallinity are formed on the substrate, the side surface of the structure after etching (laminated structure of SRO / PZT / Pt) can be close to a right angle to the substrate surface. It was.

  From this, by easily making patterns with different crystallinity of piezoelectric / electrostrictive bodies such as PZT formed by orientation on the SRO electrode layer etc. which are oriented perovskite type oxide conductors, It has been found that this is an effective means for increasing the area and improving the workability with respect to the structure, together with the stress relaxation effect at the laminated film interface described above.

Examples of the single crystal substrate used in the present invention include Si, MgO, sapphire, diamond, gallium arsenide, and the like. Was effective. It is also effective in a laminated substrate having a single crystal surface such as SOI (Si on Insulator). For example, in a Si single crystal substrate that has a proven track record as a mass-produced product, all types of substrate orientations such as substrate orientations (100), (111), and (110) can be used. Here, SiO ₂ may exist at the Si substrate surface or at the interface between the buffer layer and the Si substrate, but there is no problem if the thickness is 20 nm or less, but 10 nm or less is preferable.

  Examples of the constituent material of the buffer layer used in the present invention include the above-mentioned stabilized zirconia such as YSZ, fluorite oxide, perovskite oxide conductive material, metal material, and the like.

The fluorite type oxide, for _{example, AmO 2, CeO 2, CmO} 2, K 2 O, Li 2 O, Na 2 O, NpO 2, PaO 2, PuO 2, RbO 2, TbO 2, ThO 2, UO ₂ and ZrO ₂ , preferably CeO ₂ and ZrO ₂ . Examples of the metal material include Ni, Pt, Pb, Ir, Cu, Al, Ag, γ-Fe, Ir ₂ O ₃ , MgO, MgAl ₂ O ₄ , and preferably Pt and Ir. Perovskite oxide conductive materials include (Sr _x , Ca _y , Ba _z ) RuO ₃ (where x + y + z = 1) oxide, STO doped with La, etc., strontium titanate, CNiO ₃ oxide (C is La, Pr, Nd, at least one element selected from Sm and Eu) LaMoO _{3 in, LaCoO 3, LaCrO 3, LaAlO} 3, LaSrCoO 3, LaCuO 3, LaSrMnO 3, CaLaMnO 3, LaCaRhO ₃ , LaSrRhO ₃ , LaBaRhO _{3 and the} like. Their film thickness is 5 nm to 300 nm, preferably 20 nm to 200 nm. These buffer layers can be appropriately selected from (100), (111), (110) and other orientations according to the substrate orientation and manufacturing method described above, and by forming a plurality of layers, the substrate, electrode layer, piezoelectric / electrostrictive Lattice matching with each of the body layers can also be performed.For example, by using the above-described single crystal oxide conductor having a perovskite structure, it is possible to share the lower electrode and to shorten the process of device fabrication. Become. Such single-crystal oxide conductors have a conductivity of 1 × 10 ^-1 to 1 × 10 ^-5 W · cm as measured by the four-point needle method of Loresta-GP (MCP-600) (Mitsubishi Chemical). It was preferable to be an oxide exhibiting properties.

  The upper and lower electrode materials used in the present invention are mainly composed of at least one of Pt, Ir, Pd, Rh, Au, Ag, Ru, and the single crystal oxide conductor having the above-described perovskite structure. Preferably, these metals may be composed of a simple substance or an alloy containing them, and a plurality of layers may be used. The film thickness is 5 nm to 300 nm, preferably 20 nm to 200 nm. Examples of the orientation blocking layer material used in the present invention include metals such as Ti, Pd, Rh, Au, Ag, Ru, and Si, metal oxides containing these, and metal nitrides such as a silicon nitride film. Alternatively, a layer formed by surface modification of a single crystal substrate by electron beam drawing, ion implantation (implantation), or the like may be used. As the ion species used for implantation, many elements of the periodic table can be used, and those that change the crystallinity of the ion implantation portion of the single crystal substrate to be used can be selected as appropriate. The film thickness or layer thickness (implantation depth) of the alignment blocking layer is 100 nm or less, preferably 30 nm or less, as long as it functions as an alignment blocking layer.

As patterning means for buffer layer, orientation blocking layer, and electrode on single crystal substrate,
(1) A method in which a metal mask having a desired pattern is brought into contact with a single crystal substrate, and a buffer layer is formed by orientation or epitaxial growth by a film forming means such as a sputtering method,
(2) After a buffer layer is oriented or epitaxially formed on almost the entire surface of the single crystal substrate, a resist layer having a desired pattern is formed by photolithography, and then dry etching such as ICP, Liga process, Bosch process, ion milling or the like A method of forming a pattern by wet etching with acid or alkali such as hydrofluoric acid solution or potassium hydroxide solution, and finally removing the resist layer,
(3) Surface modification of a single crystal substrate by electron beam drawing, ion implantation, or the like.

  The buffer layer, the orientation blocking layer, and the electrode layer on the single crystal substrate of the present invention may be patterned in multiple layers.

For example, when forming a patterned lower electrode on a patterned buffer layer,
(A) A method similar to (1) above,
(B) A method similar to (2) above,
(C) After orienting or epitaxially forming a buffer layer on almost the entire surface of the single crystal substrate, a lower electrode pattern is formed by the same method as in (1) above, and this lower electrode pattern is used as a mask by a method such as wet or dry etching. A patterning method in which the pattern of the buffer layer and the lower electrode is substantially the same pattern,
Etc. can be used.

  Here, as for the relationship between the pattern of the buffer layer and the lower electrode, it is desirable that the width of at least one direction is such that the buffer layer ≧ the lower electrode in the portion excluding the lead portion of the lower electrode. That is, it is preferable to obtain a state in which these are stacked so that the end of the lower electrode does not overhang and protrude beyond the end of the buffer layer. This is because the crystallinity of the piezoelectric / electrostrictive layer formed on the lower electrode stacked out of the buffer layer is the crystal of the piezoelectric / electrostrictive layer formed on the lower electrode stacked on the buffer layer. Therefore, when etching the buffer layer and the piezoelectric / electrostrictive layer using the lower electrode layer as a mask, the piezoelectric / electrostrictive layer that protrudes from the buffer layer in the etching direction and is located below the stacked lower electrode is used. The strained body layer is easily over-etched, the piezoelectric / electrostrictive body layer is thinner than the electrode size, and the electrode protrudes in an eaves shape, which causes a short circuit when a voltage is applied (see FIG. 8B). Further, when the etching is finished before over-etching, the piezoelectric / electrostrictive layer having poor crystallinity remains in the fringe portion of the electrode, so that the characteristics as an element are deteriorated.

As the piezoelectric / electrostrictive material used in the present invention, for example, the following can be selected.
PZT [Pb (Zr _x Ti _1-x ) O ₃ ],
PMN [Pb (Mg _x Nb _1-x ) O ₃ ],
PNN [Pb (Nb _x Ni _1-x ) O ₃ ],
PSN [Pb (Sc _x Nb _1-x ) O ₃ ],
PZN [Pb (Zn _x Nb _1-x ) O ₃ ],
PMN-PT [(1-y) [Pb (Mg _x Nb _1-x ) O ₃ ] -y [PbTiO ₃ ]],
PSN-PT [(1-y) [Pb (Sc _x Nb _1-x ) O ₃ ] -y [PbTiO ₃ ]], and
PZN-PT [(1-y) [Pb (Zn _x Nb _1-x ) O ₃ ] -y [PbTiO ₃ ]]
Here, x and y are numbers of 1 or less and 0 or more. For example, in the case of PMN, x is 0.2 to 0.5, and in PSN, x is preferably 0.4 to 0.7, y of PMN-PT is 0.2 to 0.4, y of PSN-PT is 0.35 to 0.5, and y of PZN-PT is 0.03 to 0.35 is preferred.

  These piezoelectric / electrostrictive layers may have a single composition or a combination of two or more materials. Moreover, the composition which doped the trace amount element to the said main component may be sufficient. The piezoelectric / electrostrictive material to which the present invention can be applied is not limited to the above-described perovskite type piezoelectric / electrostrictive material, but is also effective for conventionally known piezoelectric / electrostrictive materials.

Next, examples of specific layer configurations of the actuator unit in the liquid jet head to which the present invention is applied will be listed. The display of the layer structure is upper electrode // (piezoelectric / electrostrictive body) thin film // lower electrode // buffer layer // substrate (vibration plate). (//: Epitaxial growth relationship, /: Epitaxial growth relationship) That is, the (piezoelectric / electrostrictive body) thin film // lower electrode is epitaxial growth.
Example 1 Pt / Ti / PZT (001) // SrRuO ₃ (100) // Si (110)
Example 2 Pt / Ti / PZT (001) // La-SrTiO ₃ (100) // Si (110)
Example 3 Pt / Ti / PZT (001) // Nb-SrTiO ₃ (100) // Si (110)
Example 4 Pt / Ti / PZT (001) // SrRuO ₃ (100) // LaNiO ₃ (100) // CeO ₂ (100) // YSZ (100) // Si (100)
Example 5 Pt / Ti / PZT (001) // SrRuO ₃ (100) / SiO ₂ / Si (110)
Example 6 Pt / Ti / PZT (001) // La-SrTiO ₃ (100) / SiO ₂ / Si (110)
Example 7 Pt / Ti / PZT (001) // Nb-SrTiO ₃ (100) / SiO ₂ / Si (110)
Example 8 Pt / Ti / PMN (001) // SrRuO ₃ (100) // Si (110)
Example 9 Pt / Ti / PMN (001) // La-SrTiO ₃ (100) // Si (110)
Example 10 Pt / Ti / PMN (001) // Nb-SrTiO ₃ (100) // Si (110)
Example 11 Pt / Ti / PMN (001) // SrRuO ₃ (100) / SiO ₂ / Si (110)
Example 12 Pt / Ti / PMN (001) // La-SrTiO ₃ (100) / SiO ₂ / Si (110)
Example 13 Pt / Ti / PMN (001) // Nb-SrTiO ₃ (100) / SiO ₂ / Si (110)
Example 14 Pt / Ti / PZT (001) / Pt (100) / YSZ (111) // Si (111)
As the above specific examples, the piezoelectric / electrostrictive thin film is exemplified by PZT and PMN, but these may have a layer configuration appropriately changed to the aforementioned PZN, PSN, PNN, PMN-PT, PSN-PT, PZN-PT. Further, a composition obtained by doping the main component with a trace element such as La such as La-doped PZT: PLZT [(Pb, La) (Z, Ti,) O ₃ ] may be used. The film thickness of the piezoelectric / electrostrictive thin film used here is preferably 300 nm to 10000 nm, more preferably 500 nm to 5000 nm as a drivable film thickness.

  In the present invention, the formation of a buffer layer on a single crystal substrate, the formation of a lower electrode on the buffer layer, the formation of a piezoelectric / electrostrictive body, and the formation of an upper electrode include sputtering, MOCVD, Sol-Gel method, MBE method, hydrothermal synthesis method, vapor deposition method, etc. are used.

  The patterning of the upper electrode on the piezoelectric / electrostrictive layer performed as necessary can be performed by the same method as that of the lower electrode described above, but the upper electrode layer is not necessarily oriented or epitaxially grown like the lower electrode. There is no need. However, as described below, when the upper electrode functions as a mask in patterning of the piezoelectric / electrostrictive layer, the upper electrode is located at a position facing the pattern of the lower electrode through the piezoelectric / electrostrictive layer. It is necessary to arrange in a shape corresponding to the lower electrode.

  As a patterning method of the piezoelectric / electrostrictive body layer of the present invention, a method using dry etching such as ICP, Liga process, Bosch process, ion milling or the like using a pattern of the upper electrode or the lower electrode as a mask, or a conventionally known resist pattern is used. A method by wet etching with an acid or alkali such as a hydrofluoric acid solution or a potassium hydroxide solution can be used after formation or with the pattern of the upper electrode or lower electrode as a direct mask. Here, the present invention uses the difference in etching rate due to the difference in crystallinity between the portion where the pattern in the same buffer layer is formed and the portion to be removed as described above, and thus is particularly effective in wet etching. It is. However, the patterning method of each layer mentioned above is not limited to this.

  As described above, by using the present invention, it is possible to provide elements that can be finely processed and have a large area and are excellent in durability and piezoelectric / electrostrictive characteristics, and manufacturing methods thereof, which are generally used in semiconductor processes. be able to. Furthermore, it has a piezoelectric / electrostrictive element structure that is excellent in durability and piezoelectric / electrostrictive characteristics, and a liquid ejection head that is long and densely formed, and has a stable and high reliability. A manufacturing method can be provided.

  Hereinafter, a liquid ejecting head (hereinafter referred to as a printer head) using a piezoelectric / electrostrictive element structure according to the present invention will be described in detail with reference to the drawings.

(Example 1)
FIG. 1A is an enlarged cross-sectional view of the printer head using the piezoelectric / electrostrictive element structure according to the present embodiment in the longitudinal direction of the diaphragm 116 and in a plane that is straight with respect to the diaphragm 116. FIG. 1B is a partially enlarged view of the printer head as viewed from above. In this printer head, a base 101 made of a silicon substrate having a thickness of 200 μm is dry-etched from above and below to provide a plurality of concave portions including the discharge ports 103 at an arrangement pitch of the discharge ports 103 of 200 dpi, which will be described later. The individual liquid chamber 102 is formed by covering the base plate 101 and the diaphragm 116 by covering with the diaphragm 116 formed on the piezoelectric / electrostrictive element structure. The individual liquid chamber 102 is formed with a width of 65 μm, a length of 3000 μm, and a depth of 100 μm. The front and rear ends in the longitudinal direction are narrowed, and the common liquid chamber 104 communicates with the rear end side. A discharge port 103 having a diameter of 15 μm is formed on the surface of the individual liquid chamber 102 facing the surface covered with the diaphragm 116. The diaphragm 116 is a portion that forms at least one surface of the individual liquid chamber 102 and is bent by deformation of the piezoelectric / electrostrictive element. A portion that is directly joined to the base 101 is not called the diaphragm 116.

  Next, the manufacturing process of the piezoelectric / electrostrictive element structure of the present invention described above will be described in detail with reference to FIGS. 2 to 4 are diagrams for explaining mainly the method for manufacturing the piezoelectric / electrostrictive element structure of the present invention in the printer head manufacturing process, when viewed from the direction perpendicular to the arrangement pitch of the discharge ports 103. FIG. FIG. First, as shown in FIG. 2A, a buffer layer metal mask having a pattern formed on the 6-inch (111) single crystal Si substrate 111 so as to correspond to the plurality of individual liquid chambers 102 in FIG. The YSZ, which is a single crystal oxide material, is epitaxially grown as the buffer layer 112 by sputtering while heating the single crystal Si substrate 111 at 800 ° C. while patterning the (111) -oriented YSZ thin film having a thickness of 100 nm. .

  Next, after removing the metal mask for the buffer layer, on the patterned YSZ buffer layer 112, a lower electrode in which an electrode drawing pattern (not shown) is added to the same size as the buffer layer pattern. The metal mask for contact is brought into contact, and the single crystal Si substrate 111 is heated to 600 ° C., and an epitaxially grown SRO lower electrode 113 as shown in FIG.

Next, after removing the metal mask for the lower electrode, a piezoelectric / electrostrictive layer PZT was formed thereon at a substrate temperature of 650 ° C. by sputtering as shown in FIG. Epitaxial growth occurred at the position where the buffer layer 112 and the lower electrode 113 were patterned, and a (001) PZT film 114 having a thickness of 3000 nm could be formed. Further, a polycrystalline film was formed in a region where the buffer layer 112 and the lower electrode 113 were not provided. Next, as shown in FIG. 3A, a Pt upper electrode 115 having Ti (4 nm) as a base layer was formed on the PZT film 114 by sputtering to a thickness of 150 nm. In this embodiment, the upper electrode 115 is used as a common electrode. This is because the upper electrode 115 is also provided with a function as an etching stop layer to be described later. For example, SiO ₂ needs to be formed.

Next, as shown in FIG. 3B, SiO ₂ is formed as a vibration plate material at a thickness of 3000 nm by sputtering to form the vibration plate 116, and an Au—Au bond with the base 101 is formed thereon. An Au layer 117 (100 nm) is provided. Examples of the material of the diaphragm 116 include a ceramic material that can be elastically deformed by the electrostriction of the piezoelectric / electrostrictive film 114, or a metal material, a metal oxide material, or a nitrogen oxide material such as zirconia, silicon, chromium, It is desirable to be composed of a thin layer of 1-30 μm, preferably 1-15 μm, such as stainless steel, silicon oxide, silicon nitride. As shown in FIG. 4A, the piezoelectric / electrostrictive element structure manufactured in this way is aligned with a substrate 101 on which an individual liquid chamber 102, a discharge port 103, a common liquid chamber (not shown), etc. are separately formed. And Au-Au bonded. Here, the base 101 and the diaphragm 116 may be joined by anodic bonding, eutectic bonding, adhesive bonding, or the like in addition to the Au-Au bonding of this embodiment.

  Next, after a resist is formed at a desired location in order to protect the portion to be left such as the base 101, predetermined portions of the single crystal substrate 111 and the piezoelectric / electrostrictive layer 114 are wet-etched with a hydrofluoric acid solution. Then, the resist was peeled off to complete the printer head. In this wet etching process, the etching rate of the piezoelectric / electrostrictive layer 114 was 120 nm / min, and the shape of the etched piezoelectric / electrostrictive layer 114 was as close to a right angle as possible with respect to the substrate surface.

  Next, a discharge experiment of the printer head having the above configuration was performed. The discharge principle of this printer head will be described with reference to FIG. When ink is supplied from an ink cartridge (not shown) from the common liquid chamber 104 to the individual liquid chamber 102 through the diaphragm 105, and a signal is applied to the upper and lower electrodes 113 and 115 from an arbitrary driving power source S, the diaphragm 116 bends. The volume of the liquid chamber 102 is changed, the ink filled in the individual liquid chamber 102 is pressurized, and the ink droplet D is ejected from the ejection port 103 by this pressure. In the printer head of this embodiment, a discharge amount of 9 pl and a discharge speed of 9 m / sec can be obtained by applying a 20 V, 10 kHz sine wave, and there is no problem in durability, and the printer head is excellent.

(Comparative Example 1)
6 to 8 are views for explaining mainly the method for manufacturing the piezoelectric / electrostrictive element structure of the present invention in the printer head manufacturing process, when viewed from the direction perpendicular to the arrangement pitch of the discharge ports 103. FIG. FIG. Here, the configuration of the printer head is the same as that of the first embodiment.

  First, as shown in FIG. 6 (a), a 6-inch size (111) single crystal Si substrate 211 is heated to 850 ° C., and YSZ, which is a single crystal oxide material, is epitaxially grown as a buffer layer 212 by sputtering. A (111) -oriented YSZ thin film having a thickness is formed. Next, as shown in FIG. 6B, a lower electrode metal mask is brought into contact with the YSZ buffer layer 212, and Pt is epitaxially grown as the lower electrode 213 by sputtering while heating at 600 ° C. The (100) -oriented Pt lower electrode 213 having a thickness is patterned. Next, after removing the metal mask for the lower electrode, as shown in FIG. 6C, a piezoelectric / electrostrictive PZT film was formed thereon at a substrate temperature of 650 ° C. by sputtering. Epitaxial growth occurred on the buffer layer 212, and a (001) PZT film 214 having a thickness of 3000 nm could be formed. However, the substrate 211 including the laminated film was warped.

Next, as shown in FIG. 7A, a Pt upper electrode 215 having Ti (4 nm) as a base layer was formed on the PZT film 214 by sputtering to a thickness of 150 nm. Next, as shown in FIG. 7B, SiO ₂ is formed into a film at 3000 nm by a sputtering method as a vibration plate material to form a vibration plate 216, on which an Au—Au bonding with the base 201 is performed. An Au layer 217 (layer thickness: 100 nm) is provided. As shown in FIG. 8A, the piezoelectric / electrostrictive element structure manufactured in this way is aligned with a base 201 on which an individual liquid chamber 202, a discharge port 203, a common liquid chamber (not shown), and the like are formed. Although Au-Au bonding was performed, bonding was not possible due to warpage of the substrate. Therefore, the substrate was heated in order to correct the warp, and after correction, the substrate 201 was bonded to the substrate 201 with an adhesive.

  Next, after forming a resist at a desired location to protect the base 201 and the like, the single crystal substrate 211, the buffer layer 213 and the piezoelectric / electrostrictive layer 214 are removed by wet etching with a hydrofluoric acid solution. Further, the resist was removed to complete the printer head. In this wet etching process, the etching rate of the piezoelectric / electrostrictive layer 214 was 70 nm / min, and the shape of the piezoelectric / electrostrictive layer 214 after etching was partially deformed due to overetching, and did not become the intended one. .

  Next, a discharge experiment of the printer head having the above configuration was performed. As in Example 1, there was a part where a discharge amount of 10 pl and a discharge speed of 9 m / sec were obtained by applying a sine wave of 20 V and 10 kHz, but there was a part where no discharge was observed. In addition, as the durability test was continued, there was a portion where the discharge was not possible.

(Example 2)
FIGS. 9 to 10 are views for explaining mainly the manufacturing method of the second piezoelectric / electrostrictive element structure according to the present invention in the printer head manufacturing process, as viewed from the direction perpendicular to the arrangement pitch of the discharge ports 103. FIGS. FIG. Here, the configuration of the printer head is substantially the same as that of the first embodiment. This printer head was manufactured using SOI-Epi wafer / ELTRAN (manufactured by Canon Inc.) 320 having a thickness of about 500 μm. In this ELTRAN, a SiO ₂ layer 322 and a single crystal Si layer 323 are formed on a Si layer 321. The Si layer 321 serves as a substrate for forming an individual liquid chamber, and the SiO ₂ layer 322 is an etching stop layer / vibration plate. The single crystal Si layer 323 serves as a single crystal substrate for manufacturing the piezoelectric / electrostrictive structure. The ELTRAN in this embodiment has a three-layer structure in which the Si layer 321 is 500 μm, the SiO ₂ layer 322 is 3 μm, and the (111) single crystal Si layer 323 is 0.3 μm.

  First, as shown in FIG. 9A, a buffer layer metal mask formed with a pattern corresponding to the plurality of individual liquid chambers 102 in FIG. Then, while heating the substrate to 850 ° C., YSZ, which is a single crystal oxide material, is epitaxially grown as a buffer layer 312 by sputtering, and a (111) -oriented YSZ thin film having a thickness of 100 nm is patterned. Next, after removing the metal mask for the buffer layer, as shown in FIG. 9B, Pt is formed on the patterned YSZ buffer layer 312 as the lower electrode 313 by sputtering while heating the substrate to 600 ° C. Epitaxial growth is performed to form a (100) -oriented Pt lower electrode 313 having a thickness of 100 nm. Next, as shown in FIG. 9C, a piezoelectric / electrostrictive PZT film was formed thereon by sputtering while heating the substrate to 650.degree. Here, the PZT layer was epitaxially grown at a position on the buffer layer 312, and a (001) PZT film 314 having a thickness of 3000 nm could be formed. In the region where the buffer layer 312 is not provided, it is a polycrystalline film. Subsequently, a Pt upper electrode 315 having Ti (4 nm) as a base layer was formed by patterning at a position corresponding to the individual liquid chamber on the PZT film 314 with a thickness of 150 nm.

Next, as shown in FIG. 10A, unnecessary portions of the PZT layer 314 are removed by wet etching with a hydrofluoric acid solution. At this time, the Pt lower electrode 313 becomes an etching stop layer. Subsequently, as shown in FIG. 10B, the ELTRAN Si layer is wet-etched with a hydrofluoric acid solution to form individual liquid chambers and common liquid chambers. In this step, the SiO ₂ layer 322 serves as an etching stop layer and further serves as a diaphragm. Finally, a nozzle plate having a plurality of discharge ports formed on the SUS substrate was joined with an adhesive to complete the printer head of the present invention.

  In this wet etching process, the etching rate was 120 nm / min, and the shape of the etched PZT layer 314 was also as intended to be close to a right angle to the substrate surface.

  Next, a discharge experiment of the printer head having the above configuration was performed. In the printer head of this embodiment, a discharge amount of 10 pl and a discharge speed of 9 m / sec can be obtained by applying a sine wave of 20 V and 10 kHz, and there is no problem in durability, and the printer head is excellent.

(Example 3)
FIGS. 11 to 12 are diagrams for explaining mainly the method of manufacturing the third piezoelectric / electrostrictive element structure according to the present invention in the printer head manufacturing process, as viewed from the direction perpendicular to the arrangement pitch of the discharge ports. FIG. Here, the configuration of the printer head is substantially the same as that of the first embodiment. This printer head was manufactured using SOI-Epi wafer / ELTRAN (manufactured by Canon Inc.) 420 having a thickness of about 500 μm. In this ELTRAN, a SiO ₂ layer 422 and a single crystal Si layer 423 are formed on a Si layer 421, and the Si layer 421 serves as a substrate for forming an individual liquid chamber, and the SiO ₂ layer 422 is an etching stop layer / vibration plate, The single crystal Si layer 423 serves as a single crystal substrate for manufacturing the piezoelectric / electric element structure. The ELTRAN in this embodiment has a three-layer structure in which the Si layer 421 is 500 μm, the SiO ₂ layer 422 is 3 μm, and the (111) single crystal Si layer 423 is 0.3 μm. First, as shown in FIG. 11A, a metal mask having a pattern formed so as to substantially hide the plurality of individual liquid chambers 102 shown in FIG. 1B is abutted on the 6-inch ELTRAN substrate 420 described above. Then, Ti is deposited to a thickness of 50 nm as the orientation blocking layer 416. Next, while heating the substrate to 850 ° C., as shown in FIG. 11B, YSZ, which is a single crystal oxide material, is formed as the buffer layer 412 by sputtering so as to cover the above-described patterned orientation blocking layer 416. Subsequently, a Pt film having a thickness of 100 nm is formed as the lower electrode 413 on the YSZ buffer layer 412 by sputtering while heating the substrate to 600 ° C. At this time, YSZ and Pt are epitaxially grown at (111) and (100) at portions other than the patterned alignment blocking layer 416, and YSZ and Pt formed on the alignment blocking layer 416 are not epitaxially grown. Next, as shown in FIG. 11C, a piezoelectric / electrostrictive PZT film was formed thereon by sputtering while heating the substrate to 650.degree. Here, the PZT layer was epitaxially grown on the epitaxially grown Pt, and a (001) PZT film 414 having a thickness of 3000 nm could be formed. Similarly, PZT is not epitaxially grown in a region where Pt is not epitaxially grown. Subsequently, a Pt upper electrode 415 having a Ti (4 nm) layer as a base layer was formed by patterning at a position corresponding to the individual liquid chamber on the PZT film 414 with a thickness of 150 nm.

Next, as shown in FIG. 12A, unnecessary PZT layer 414 is removed by wet etching with a hydrofluoric acid solution. At this time, the lower electrode layer 413 becomes an etching stop layer. Subsequently, as shown in FIG. 12B, the ELTRAN Si layer is wet-etched with a hydrofluoric acid solution to form individual liquid chambers and a common liquid chamber. In this step, the SiO ₂ layer 422 serves as an etching stop layer and further serves as a diaphragm. Finally, the nozzle plate 424 having a plurality of discharge ports formed on the SUS substrate was joined with an adhesive to complete the printer head of the present invention.

  In this wet etching step, the etching rate was 150 nm / min, and the shape of the etched PZT layer 414 was also as intended to be close to a right angle to the substrate surface.

  Next, a discharge experiment of the printer head having the above configuration was performed. In the printer head of this embodiment, a discharge amount of 10 pl and a discharge speed of 9 m / sec can be obtained by applying a sine wave of 20 V and 10 kHz, and there is no problem in durability, and the printer head is excellent.

Example 4
FIGS. 13 to 14 are views for explaining mainly the fourth piezoelectric / electrostrictive element structure manufacturing method of the present invention in the printer head manufacturing process, as viewed from the direction perpendicular to the arrangement pitch of the discharge ports. FIG. Here, the configuration of the printer head is substantially the same as that of the first embodiment. This printer head was manufactured using SOI-Epi wafer / ELTRAN (manufactured by Canon Inc.) 520 having a thickness of about 500 μm. In this ELTRAN, a SiO ₂ layer 522 and a single crystal Si layer 523 are formed on a Si layer 521, and the Si layer 521 serves as a substrate for forming an individual liquid chamber. The SiO ₂ layer 522 is an etching stop layer / vibration plate, The single crystal Si layer 523 serves as a single crystal substrate for manufacturing the piezoelectric / electric element structure. The ELTRAN in this example has a three-layer structure in which the Si layer 521 is 500 μm, the SiO ₂ layer 522 is 3 μm, and the (100) single crystal Si layer 523 is 0.3 μm. First, as shown in FIG. 13A, a single crystal oxide material YSZ and CeO ₂ are continuously formed as a buffer layer by a sputtering method while heating the substrate to the above-described 6 inch size ELTRAN substrate 520 at 850 ° C. Epitaxial growth is performed to form a (100) -oriented YSZ layer 531 and a CeO ₂ layer 532 having a thickness of 100 nm and 5 nm, respectively. Next, a lower electrode metal mask having a pattern corresponding to the plurality of individual liquid chambers 102 in FIG. 1B is brought into contact with the perovskite type single crystal oxide conductor as shown in FIG. 13B. LaNiO ₃ and SrRuO ₃ as the lower electrode layers are continuously formed by heating the substrate at 600 ° C., and patterned (100) LaNiO ₃ layer 533 and (100) SrRuO ₃ layer 534 are formed. Next, as shown in FIG. 13 (c), a PZT film 535, which is a piezoelectric / electrostrictive body, was formed thereon with a thickness of 3000 nm by sputtering while heating the substrate to 650 ° C. On the (100) LaNiO ₃ layer 533 and the (100) SrRuO ₃ layer 534 patterned here, the PZT layer 535 is epitaxially grown. Further, the crystallinity is lower in the region other than the electrode region as compared with the electrode region. Subsequently, a Pt upper electrode 536 having Ti (4 nm) as a base layer was formed by patterning at a position corresponding to the individual liquid chamber on the PZT layer 535 with a thickness of 150 nm.

Next, as shown in FIG. 14A, the PZT layer 535 is removed by wet etching with a hydrofluoric acid solution. At this time, the YSZ layer 531 and the CeO ₂ layer 532 serving as a buffer layer serve as an etching stop layer. Subsequently, as shown in FIG. 14B, the ELTRAN Si layer is wet-etched with a hydrofluoric acid solution to form individual liquid chambers and common liquid chambers. In this step, the SiO ₂ layer 522 serves as an etching stop layer and further serves as a diaphragm. Finally, as shown in FIG. 14C, a nozzle plate 524 having a plurality of discharge ports formed on a SUS substrate was joined with an adhesive to complete the printer head of the present invention.

  In this wet etching process, the etching rate was 90 nm / min, and the shape of the etched PZT layer 535 was also as intended to be close to a right angle to the substrate surface.

  Next, a discharge experiment of the printer head having the above configuration was performed. In the printer head of this embodiment, a discharge amount of 10 pl and a discharge speed of 9 m / sec can be obtained by applying a sine wave of 20 V and 10 kHz, and there is no problem in durability, and the printer head is excellent.

FIG. 2 is an enlarged cross-sectional view (a) of the printer head according to the first embodiment of the present invention and a partially enlarged view (b) when viewed from above. It is sectional drawing of the arrangement direction of the ejection opening which shows the manufacturing process of the printer head which concerns on Example 1 of this invention. It is sectional drawing of the arrangement direction of the ejection opening which shows the manufacturing process of the printer head which concerns on Example 1 of this invention. It is sectional drawing of the arrangement direction of the ejection opening which shows the manufacturing process of the printer head which concerns on Example 1 of this invention. It is a figure which shows an example of the mask pattern used in order to solve a subject. It is sectional drawing of the arrangement direction of the discharge outlet which shows the manufacturing process of a comparative example. It is sectional drawing of the arrangement direction of the discharge outlet which shows the manufacturing process of a comparative example. It is sectional drawing of the arrangement direction of the discharge outlet which shows the manufacturing process of a comparative example. It is sectional drawing of the arrangement direction of the ejection opening which shows the manufacturing process of the printer head which concerns on Example 2 of this invention. It is sectional drawing of the arrangement direction of the ejection opening which shows the manufacturing process of the printer head which concerns on Example 2 of this invention. It is sectional drawing of the arrangement direction of the ejection opening which shows the manufacturing process of the printer head which concerns on Example 3 of this invention. It is sectional drawing of the arrangement direction of the ejection opening which shows the manufacturing process of the printer head which concerns on Example 3 of this invention. It is sectional drawing of the arrangement direction of the ejection opening which shows the manufacturing process of the printer head which concerns on Example 4 of this invention. It is sectional drawing of the arrangement direction of the ejection opening which shows the manufacturing process of the printer head which concerns on Example 4 of this invention.

Explanation of symbols

101 Substrate 102 Individual liquid chamber 103 Discharge port 111 Single crystal substrate 112 Buffer layer 113 Lower electrode 114 Piezoelectric / electrostrictive film 115 Upper electrode 116 Diaphragm 117 Au film

Claims (18)

A method for manufacturing a piezoelectric / electrostrictive element structure having a piezoelectric / electrostrictive film, a lower electrode and an upper electrode sandwiching the piezoelectric / electrostrictive film,
Forming a buffer layer oriented and grown in a pattern on a single crystal substrate;
Aligning and growing the lower electrode layer on the buffer layer;
A step of orientationally growing the piezoelectric / electrostrictive film so as to cover the buffer layer and the lower electrode layer;
Removing a portion of the piezoelectric / electrostrictive film other than the portion grown by orientation following the pattern of the buffer layer by an etching process;
A method for manufacturing a piezoelectric / electrostrictive element structure, comprising:   The method for manufacturing a piezoelectric / electrostrictive element structure according to claim 1, wherein the orientation growth is epitaxial growth.   The method further comprises the step of forming the upper electrode layer on the piezoelectric / electrostrictive film between the step of orientation-growing the piezoelectric / electrostrictive film and the step of removing by the etching process. A method for manufacturing a piezoelectric / electrostrictive element structure according to claim 1 or 2.   The method for manufacturing a piezoelectric / electrostrictive element structure according to claim 1, wherein the etching treatment is wet etching.   4. The method for manufacturing a piezoelectric / electrostrictive element structure according to claim 1, wherein the etching process is dry etching.   A patterned orientation blocking layer is formed on the single crystal substrate, and the buffer layer is oriented and grown on a portion of the single crystal substrate other than the portion where the orientation blocking layer is formed, thereby forming the patterned shape. A method for producing a piezoelectric / electrostrictive element structure according to claim 1, wherein a buffer layer oriented and grown is formed.   7. The method for manufacturing a piezoelectric / electrostrictive element structure according to claim 1, wherein the lower electrode is made of a perovskite oxide conductive material. The lower _{electrode, (Sr x, Ca y,} Ba z) RuO 3 ( where x + y + z = 1) based piezoelectric / electrostrictive element structure according to claim 7, characterized in that an oxide Body manufacturing method. 2. The piezoelectric / electrostrictive according to claim 1, wherein the lower electrode is made of a CNiO ₃ -based oxide, and C is at least one element selected from La, Pr, Nd, Sm, and Eu. Manufacturing method of body element structure.   A piezoelectric / electrostrictive element structure manufactured by the method for manufacturing a piezoelectric / electrostrictive element structure according to claim 1. A method for manufacturing a piezoelectric / electrostrictive element structure having a piezoelectric / electrostrictive film, a lower electrode and an upper electrode sandwiching the piezoelectric / electrostrictive film,
Forming a buffer layer oriented and grown on a single crystal substrate;
Forming the lower electrode layer oriented and grown in a pattern on the buffer layer;
A step of orientationally growing the piezoelectric / electrostrictive film so as to cover the buffer layer and the lower electrode layer;
Removing a portion of the piezoelectric / electrostrictive film other than the portion grown by orientation following the pattern of the lower electrode layer by an etching process;
A method for manufacturing a piezoelectric / electrostrictive element structure, comprising:   12. The method for manufacturing a piezoelectric / electrostrictive element structure according to claim 11, wherein the orientation growth is epitaxial growth.   The method further comprises the step of forming the upper electrode layer on the piezoelectric / electrostrictive film between the step of orientation-growing the piezoelectric / electrostrictive film and the step of removing by the etching process. A method for manufacturing a piezoelectric / electrostrictive element structure according to claim 11 or 12.   The method for manufacturing a piezoelectric / electrostrictive element structure according to claim 11, wherein the etching treatment is wet etching.   The method for manufacturing a piezoelectric / electrostrictive element structure according to claim 11, wherein the etching treatment is dry etching.   A piezoelectric / electrostrictive element structure manufactured by the method for manufacturing a piezoelectric / electrostrictive element structure according to claim 11. A piezoelectric / electrostrictive film provided in correspondence with the liquid chamber, the piezoelectric / electrostrictive film, and a lower electrode and an upper electrode sandwiching the piezoelectric / electrostrictive film; An electrostrictive element structure, and a manufacturing method of a liquid jet head comprising:
Forming a buffer layer oriented and grown in a pattern on a single crystal substrate;
Aligning and growing the lower electrode layer on the buffer layer;
A step of orientationally growing the piezoelectric / electrostrictive film so as to cover the buffer layer and the lower electrode layer;
Removing a portion of the piezoelectric / electrostrictive film other than the portion grown by orientation following the pattern of the buffer layer by an etching process;
A method for manufacturing a liquid jet head, comprising: A piezoelectric / electrostrictive film provided in correspondence with the liquid chamber, the piezoelectric / electrostrictive film, and a lower electrode and an upper electrode sandwiching the piezoelectric / electrostrictive film; An electrostrictive element structure, and a manufacturing method of a liquid jet head comprising:
Forming a buffer layer oriented and grown on a single crystal substrate;
Forming the lower electrode layer oriented and grown in a pattern on the buffer layer;
A step of orientationally growing the piezoelectric / electrostrictive film so as to cover the buffer layer and the lower electrode layer;
Removing a portion of the piezoelectric / electrostrictive film other than the portion grown by orientation following the pattern of the lower electrode layer by an etching process;
A method for manufacturing a liquid jet head, comprising:

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