JP2005191289A - Piezoelectric actuator and method for manufacturing liquid spray head using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for steadily obtaining a piezoelectric actuator, having a piezoelectric film high in the degree of 100-plane orientation. <P>SOLUTION: The method comprises a step of forming a lower electrode 33 on a substrate 10, a step of forming a titanium seed layer on the lower electrode 33 by sputtering method, a step of forming a piezoelectric film 43 on the titanium seed layer, and a step of forming an upper electrode 44 on the piezoelectric film 43. The sputtering time, in the titanium seed layer forming step, is ≥2% and ≤20% of the sputtering time that the same sputtering apparatus requires, when it forms a continuous film of titanium used in the sputtering method. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a piezoelectric actuator having an electromechanical conversion function, a liquid ejecting head using the same, and a liquid ejecting apparatus.

  Conventionally, there is an ink jet recording head as an example of a liquid ejecting head. This ink jet recording head uses a piezoelectric actuator as a drive source for ink ejection of a printer. The piezoelectric actuator generally includes a pressure generation chamber that communicates with a nozzle opening (discharge port) that discharges ink droplets, a vibration plate that defines one surface of the pressure generation chamber, a lower electrode formed on the vibration plate, And a piezoelectric element having a piezoelectric film and an upper electrode. In such an ink jet recording head, various improvements have been made for the purpose of obtaining stable droplet discharge characteristics and improving reliability.

For example, in Japanese Patent Laid-Open No. 2001-88294, a titanium layer having a thickness of 2 nm to 10 nm is laminated on a lower electrode containing iridium, and an amorphous film containing a metal element and an oxygen element constituting a ferroelectric is formed thereon. It is disclosed to form a ferroelectric thin film crystallized with a (100) plane preferred orientation by forming and heat-treating the amorphous film.
JP 2001-88294 A

  However, even in the conventional film forming method, the degree of orientation in the 100 plane may vary depending on various conditions, and it is necessary to obtain the desired orientation more stably. In particular, it is necessary to stably obtain a piezoelectric film having a high degree of orientation in the 100 plane.

  SUMMARY An advantage of some aspects of the invention is to provide a manufacturing method capable of stably obtaining a piezoelectric actuator including a piezoelectric film having a high degree of orientation in 100 plane, and a liquid ejecting head and a liquid ejecting apparatus using the same.

  In order to achieve this object, the present invention includes a step of forming a lower electrode on a substrate, a step of forming a seed titanium layer on the lower electrode by a sputtering method, and a piezoelectric film formed on the seed titanium layer. And a step of forming an upper electrode on the piezoelectric film, wherein the sputtering time in the step of forming the seed titanium layer is determined by the sputtering apparatus used for the sputtering method. 2% to 20% of the required sputtering time for forming the continuous film.

  Thereby, the seed titanium layer can be formed in a good island shape, and the degree of orientation of the 100 plane of the piezoelectric film formed thereafter can be stably increased.

  In the manufacturing method, the pressure in the sputtering apparatus in the step of forming the seed titanium layer is preferably 2 Pa or more and 5 Pa or less. Thereby, the sputtered Ti particles can be moderately decelerated to reach the lower electrode, and can be deposited in a good island shape.

  In the above manufacturing method, the sputtering power in the step of forming the seed titanium layer is preferably 50 W or more and 100 W or less. Thereby, even if the pressure in the apparatus is increased, the Ti element can be sputtered satisfactorily. Also, the seed titanium layer can be deposited efficiently even if the sputtering time is shortened.

  In the manufacturing method described above, the sputtering time in the step of forming the seed titanium layer is desirably 1 second or longer and 12 seconds or shorter. Thereby, a seed titanium layer can be made into a more favorable island shape, and the 100-plane orientation degree of a piezoelectric material film can be made high stably.

  In the manufacturing method, in the step of forming the seed titanium layer, it is preferable that the seed titanium layer is formed to an average thickness of 0.1 nm to 1 nm. Thereby, a seed titanium layer can be made into a more favorable island shape, and the 100-plane orientation degree of a piezoelectric material film can be made high stably.

  In the above manufacturing method, the piezoelectric film is preferably made of PZT or a solid solution containing this as a main component. PZT or a solid solution containing this as a main component is particularly excellent in piezoelectric characteristics and contains titanium, so that the crystal growth can be favorably performed using the seed titanium layer as a nucleus.

  The method of manufacturing a liquid jet head according to the present invention includes a step of forming a piezoelectric actuator by the above-described manufacturing method, a step of forming a pressure generating chamber whose internal volume changes due to mechanical displacement of the piezoelectric actuator, and the pressure generating chamber And a step of forming a discharge port that discharges the liquid droplets in communication therewith. As a result, the piezoelectric film, which is a constituent element of the piezoelectric actuator, has a high degree of orientation in the 100 plane and has good piezoelectric characteristics, so that a liquid jet head having high performance and high reliability can be obtained.

  The piezoelectric actuator of the present invention is manufactured by the above manufacturing method. Since this piezoelectric actuator includes a piezoelectric film having a high degree of orientation on the 100 plane and good piezoelectric characteristics, it has high performance and high reliability.

  The present invention also includes the piezoelectric actuator according to the present invention described above, a pressure generation chamber whose internal volume changes due to mechanical displacement of the actuator, a discharge port that communicates with the pressure generation chamber and discharges droplets. A liquid ejecting head including the above is provided.

  The liquid ejecting head having this configuration has high performance and high reliability because the piezoelectric film, which is a component of the piezoelectric actuator, has a high degree of orientation in the 100 plane and can obtain good piezoelectric characteristics. Yes.

  Furthermore, the present invention provides a liquid ejecting apparatus including the above-described liquid ejecting head according to the present invention and a driving device that drives the liquid ejecting head.

  The liquid ejecting apparatus having this configuration has high performance and high reliability because a piezoelectric actuator, which is a constituent element of the liquid ejecting head, can obtain good piezoelectric characteristics with a high degree of orientation of the piezoelectric film in the 100 plane. have.

  Next, a piezoelectric actuator according to a preferred embodiment of the present invention, a liquid jet head using the piezoelectric actuator, and a manufacturing method thereof will be described with reference to the drawings.

  Note that in this embodiment, an ink jet recording head that ejects ink droplets as a liquid ejecting head and a printer that includes an ink jet recording head as a liquid ejecting apparatus will be described as an example. The embodiments described below are examples for explaining the present invention, and the present invention is not limited only to these embodiments. Therefore, the present invention can be implemented in various forms without departing from the gist thereof.

  1 is a perspective view showing a printer according to the present embodiment, FIG. 2 is an exploded perspective view of an ink jet recording head used in the printer shown in FIG. 1, and FIG. 3 is an ink jet recording head shown in FIG. FIG. 4 is a cross-sectional view taken along line ii shown in FIG. 3, FIG. 5 is a cross-sectional view taken along line ii-ii shown in FIG. 3, and FIGS. FIG. 7 is a process diagram illustrating a method for manufacturing the piezoelectric actuator and the ink jet recording head according to the present embodiment.

  As shown in FIG. 1, the printer 1 according to this embodiment includes a head unit 200 having a plurality of ink jet recording heads 220 (see FIG. 2), and the head unit 200 constitutes an ink supply unit. Cartridges 1A and 1B are detachably provided. In the present embodiment, the cartridge 1A has one chamber and contains a black ink composition. The cartridge 1B is partitioned into, for example, three rooms, and each room contains a cyan ink composition, a magenta ink composition, and a yellow ink composition. A head unit 200 on which these cartridges 1A and 1B are detachably mounted is mounted on a carriage 3. The carriage 3 is provided on a carriage shaft 5 attached to a printer body 4 so as to be movable in the axial direction. Yes.

  The printer body 4 is provided with a drive motor 6 for driving the carriage 3, and the driving force of the drive motor 6 is transmitted to the carriage 3 through a plurality of gears and a timing belt 7 (not shown). Thus, the carriage 3 on which the head unit 200 is mounted is moved along the carriage shaft 5.

  Further, the printer body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S that is a recording medium such as paper fed by a paper feed roller (not shown) is conveyed on the platen 8. It has become so. A desired ink composition is ejected from the head unit 200 onto the recording sheet S at a desired timing, so that characters, images, and the like are printed.

  As shown in FIGS. 2 to 5, the ink jet recording head 220 according to the present embodiment includes a flow path forming substrate 10 in which a pressure generating chamber 12 communicating with the nozzle openings 21 is formed, and one of the flow path forming substrates 10. The piezoelectric element 300 is provided on the direction side with a diaphragm 50 interposed therebetween. The diaphragm 50 and the piezoelectric element 300 constitute a piezoelectric actuator as a drive source for increasing the pressure in the pressure generating chamber 12 and ejecting ink droplets from the nozzle openings 21.

The flow path forming substrate 10 is composed of a silicon single crystal substrate, and a vibration plate 50 formed on one side of the flow path forming substrate 10 is formed by previously oxidizing the flow path forming substrate 10 by thermal oxidation. It is composed of an oxide film 51 made of silicon (SiO ₂ ) and a diffusion prevention film 52 formed on the oxide film 51. (See FIGS. 4 and 5). In this embodiment, the diffusion prevention film 52 is composed of a zirconium oxide (ZrO ₂ ) film, and lead (Pb) contained in a piezoelectric film 43 described later is diffused into the oxide film 51. It has a function to prevent this.

  The flow path forming substrate 10 is formed with a plurality of pressure generating chambers 12 partitioned by a plurality of partition walls 22 by anisotropic etching from the other side. On the outer side in the longitudinal direction of each pressure generating chamber 12, a communicating portion 13 is formed which communicates with a reservoir portion 31 provided on a reservoir forming substrate 30 to be described later and constitutes a reservoir 100 serving as a common ink chamber for each pressure generating chamber 12. Has been. The communication portion 13 is in communication with one end portion in the longitudinal direction of each pressure generating chamber 12 through the ink supply path 14.

  On the opening surface side of the flow path forming substrate 10, a nozzle plate 20 having a nozzle opening 21 communicating with the side opposite to the ink supply path 14 of each pressure generating chamber 12 is provided via an adhesive, a heat welding film, or the like. It is fixed. That is, in the present embodiment, two rows of nozzle rows 21 </ b> A in which the nozzle openings 21 are arranged in parallel are provided in one ink jet recording head 220.

  A piezoelectric element 300 including a lower electrode 33 patterned in a predetermined shape, a piezoelectric film 43 made of lead zirconate titanate (PZT), and an upper electrode 44 is formed on the diaphragm 50. ing. In this piezoelectric element 300, since the lower electrode 33 is patterned, an adhesion region 53 in which the piezoelectric film 43 and the diffusion prevention film 52 are in close contact (contact) is formed.

  A reservoir forming substrate 30 having a reservoir portion 31 constituting at least a part of the reservoir 100 is joined on the flow path forming substrate 10 on which such a piezoelectric element 300 is formed. In the present embodiment, the reservoir portion 31 is formed across the reservoir forming substrate 30 in the thickness direction and across the width direction of the pressure generating chamber 12. A reservoir 100 that is in communication with the unit 13 and serves as an ink chamber common to the pressure generation chambers 12 is configured.

  Examples of the reservoir forming substrate 30 include glass, ceramic, metal, plastic, and the like. However, it is preferable to use a material that is substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10. Then, the silicon single crystal substrate made of the same material as the flow path forming substrate 10 was used.

  Furthermore, a drive IC 110 for driving each piezoelectric element 300 is provided on the reservoir forming substrate 30. Each terminal of the drive IC 110 is connected to a lead wiring drawn from an individual electrode of each piezoelectric element 300 via a bonding wire or the like (not shown). Each terminal of the driving IC 110 is connected to the outside via an external wiring 111 such as a flexible printed cable (FPC), and receives various signals such as a print signal from the outside via the external wiring 111. .

  A compliance substrate 40 is bonded on the reservoir forming substrate 30. In the region of the compliance substrate 40 facing the reservoir 100, an ink introduction port 45 for supplying ink to the reservoir 100 is formed by penetrating in the thickness direction. Further, the region other than the ink inlet 45 in the region facing the reservoir 100 of the compliance substrate 40 is a flexible portion 46 formed thin in the thickness direction, and the reservoir 100 is sealed by the flexible portion 46. Has been. The flexible portion 46 provides compliance within the reservoir 100.

  As described above, the ink jet recording head 220 according to the present embodiment includes the four substrates of the nozzle plate 20, the flow path forming substrate 10, the reservoir forming substrate 30, and the compliance substrate 40. On the compliance substrate 40 of the ink jet recording head 220, the ink introduction port 45 communicates with an ink communication path of a cartridge case (not shown), and ink from the cartridge case is supplied to the ink introduction port 45. A head case 230 is provided in which an ink supply communication path 231 is provided. The head case 230 is provided with a recess (not shown) in a region facing the flexible portion 46 so that the flexible portion 46 is flexibly deformed. The head case 230 is provided with a drive IC holding part 233 penetrating in the thickness direction in a region facing the drive IC 110 provided on the reservoir forming substrate 30, and the external wiring 111 is connected to the drive IC holding part. The drive IC 110 is connected through the H.233.

  Such an ink jet recording head 220 takes in ink supplied from the ink cartridge from the ink introduction port 45, fills the interior from the reservoir 100 to the nozzle opening 21, and then in accordance with a recording signal from the drive IC 110, A voltage is applied to each piezoelectric element 300 corresponding to the pressure generating chamber 12 to cause the diaphragm 50 to bend and deform, thereby increasing the pressure in each pressure generating chamber 12 and ejecting ink droplets from the nozzle openings 21.

  Next, a method for manufacturing the ink jet recording head 220 according to the present embodiment will be described with reference to FIGS.

(Diaphragm forming step: S1)
A flow path forming substrate 10 made of a silicon single crystal substrate (for example, a thickness of about 200 μm) is treated at a high temperature in an oxidizing atmosphere containing oxygen or water vapor, and an oxide film 51 made of a silicon dioxide film is formed on the flow path forming substrate 10. (For example, a thickness of about 1 μm) is formed. In this step, the CVD method can be used in addition to the thermal oxidation method that is usually used.

  Next, a diffusion prevention film 52 (for example, a thickness of about 200 nm to 400 nm) made of a zirconium oxide film is formed on the oxide film 51. The diffusion prevention film 52 is obtained by forming a zirconium layer by, for example, a sputtering method or a vacuum deposition method and performing a high temperature treatment in an oxygen atmosphere. Alternatively, zirconium oxide may be directly formed by performing RF sputtering using a zirconium oxide target. In this way, the diaphragm 50 composed of the oxide film 51 and the diffusion preventing film 52 is formed.

(Process for forming lower electrode forming film: S2)
Next, on the diffusion prevention film 52, a lower electrode forming film 33a for forming the lower electrode 33 is formed by patterning in a step described later. In the present embodiment, the lower electrode forming film 33a includes, for example, a step of forming a layer containing iridium (Ir) by sputtering or the like, and platinum (Pt) by sputtering or the like on the Ir layer. It was formed by performing a step of forming a layer and a step of forming a layer containing iridium on the Pt layer by sputtering or the like. Note that an adhesion layer (not shown) made of titanium may be formed on the diffusion preventing film 52 by sputtering or vacuum deposition prior to the formation of the lower electrode forming film 33a.

  After forming the lower electrode forming film 33a, a titanium (Ti) layer (not shown) is formed on the lower electrode forming film 33a continuously. This titanium layer has a function as a nucleus for crystallizing the piezoelectric precursor film 43a to be formed later. By crystallizing the piezoelectric precursor film 43a using the titanium crystal as a nucleus, Growth occurs from the lower electrode forming film 33a side, and a dense columnar crystal can be obtained. This titanium layer is preferably formed by, for example, sputtering.

  The titanium layer is preferably formed in an island shape in which the film is not continuously formed on the lower electrode forming film 33a but is partially present. In particular, it is preferable to form a film with a sputtering time of 2% or more and 20% or less with respect to a required sputtering time in which a continuous film of titanium can be formed by the sputtering apparatus. By setting the sputtering time, an optimum island-shaped titanium layer can be formed. For example, when the required sputtering time for forming a continuous film of titanium is 1 minute and the film thickness at that time is 5 nm, the film thickness is set to 1 to 12 seconds under the same conditions. Can form an island-shaped titanium layer having an average of 0.1 nm to 1 nm. Accordingly, a sputtering time and an average film thickness within this range are preferable.

  The atmosphere in the sputtering apparatus for forming the titanium layer is an inert gas atmosphere such as argon, and the pressure is preferably 2 Pa or more and 5 Pa or less, and more preferably 3 Pa or more and 4 Pa or less. Increasing the pressure in the atmosphere as described above is considered to contribute to forming an appropriate island-shaped titanium layer by appropriately decelerating the sputtered titanium particles to reach the lower electrode. Moreover, it is preferable that the sputtering power is set high and is 50 W or more and 100 W or less. Thereby, even if the pressure in the apparatus is increased, titanium particles can be blown onto the lower electrode, and the seed titanium layer can be deposited efficiently even in a short sputtering time.

(First piezoelectric film forming step: S3 and S4)
Next, the piezoelectric precursor film 43a is formed on the lower electrode forming film 33a with a thickness not more than a desired thickness of the piezoelectric film 43 to be finally formed, preferably not more than half of the desired thickness. Form. For example, when the entire piezoelectric film 43 having a film thickness of 1.5 μm is composed of seven layers, in this first step, the piezoelectric precursor film 43a having a thickness of 0.1 μm to 0.2 μm consisting of at least one layer is formed. (See S3).

  Specifically, a sol made of an organometallic alkoxide solution is applied onto the lower electrode forming film 33a by a sol-gel method by a coating method such as spin coating. Then, it is dried at a constant temperature for a certain time, and the solvent is evaporated. After drying, the product is further degreased at a predetermined high temperature for a certain period of time in an air atmosphere to thermally decompose the organic ligand coordinated to the metal to obtain a metal oxide. The piezoelectric precursor film 43a is laminated by repeating the coating, drying, and degreasing steps a predetermined number of times, for example, twice. By these drying and degreasing treatments, the metal alkoxide and acetate in the solution form a metal, oxygen, and metal network through thermal decomposition of the ligand.

  Next, the piezoelectric precursor film 43a is fired and crystallized. By this firing, the piezoelectric precursor film 43a changes from an amorphous state to a rhombohedral crystal structure and changes to a film exhibiting an electromechanical conversion action. By performing the steps of forming and firing the piezoelectric precursor film 43a as described above, a first piezoelectric film 43b consisting of one layer is formed. (See S4).

  The thus formed first piezoelectric film 43b is influenced by the composition of the lower electrode forming film 33a and the titanium layer, and the (100) plane orientation degree measured by the X-ray diffraction wide angle method is 90% or more. . The (110) plane orientation degree is 5% or less, and the (111) plane orientation degree is the balance. Here, the (100) plane orientation degree indicates the ratio of the diffraction intensity of the (100) plane when the sum of the diffraction intensities of the (100) plane, the (110) plane, and the (111) plane is 100. . In addition, with the firing, the lower electrode forming film 33a is also partially oxidized, and the film thickness is increased by partially diffusing the components of the piezoelectric film. Here, in the method of forming the piezoelectric film after patterning the lower electrode formation film, the increase in the film thickness in the vicinity of the patterning boundary of the lower electrode formation film is smaller than in the other portions, resulting in non-uniform film thickness. However, according to the method of the present embodiment, since the first piezoelectric film 43b is formed before the lower electrode forming film 33a is patterned, the film thickness of the lower electrode forming film 33a increases as a whole. It will not be uneven.

(Patterning process of lower electrode forming film and first piezoelectric film: S5)
Next, a mask having a desired shape is formed on the first piezoelectric film 43b, and the first piezoelectric film 43b and the lower electrode forming film 33a are patterned by etching the portions other than the mask region, so that the lower electrode 33 and wiring electrode 33b are formed. Specifically, first, a resist material having a uniform thickness is applied on the first piezoelectric film 43b by a spinner method, a spray method, or the like (not shown), and then the resist material is patterned into a predetermined shape. Then, exposure and development are performed to form a resist pattern (not shown), and using this as a mask, the first piezoelectric film 43b and the lower electrode forming film 33a are etched away by a commonly used ion milling or dry etching method or the like. Then, the diffusion prevention film 52 is exposed.

(Second piezoelectric film forming step: S6)
Next, on the first piezoelectric film 43b and the exposed diffusion preventing film 52, the same process as the first piezoelectric film forming process is repeated, for example, six times to form a second piezoelectric film. A piezoelectric film 43 having a total thickness of 1.5 μm is formed. In the second piezoelectric film forming step, a piezoelectric precursor film is formed and fired and crystallized in the same manner as in the first piezoelectric film forming step. Before forming the second piezoelectric film, an ultrathin seed titanium layer of 1 nm or less may be formed on the first piezoelectric film 43b and the exposed diffusion prevention film 52 by sputtering or the like. good.

  At the time of firing the second piezoelectric film, lead contained in the piezoelectric precursor film on the diffusion preventing film 52 tries to diffuse into the diffusion preventing film 52. Lead does not reach the oxide film 51. This diffusion prevention film 52 can exhibit a sufficient diffusion prevention function even if its film thickness is as thin as, for example, about 200 nm to 400 nm.

  Since the lower electrode 33 has already been oxidized and diffused by firing in the first piezoelectric film forming step and the film thickness has increased overall, the thickness of the lower electrode 33 is further increased in the second piezoelectric film forming step. There is no increase. Accordingly, the film thickness of the lower electrode 33 does not become uneven, and the piezoelectric film 43 existing near the patterning boundary of the lower electrode 33 is cracked due to a change in the film thickness of the lower electrode 33 or the crystal is film surface. There is no discontinuity in the direction. Furthermore, a crystal structure is formed between the first piezoelectric film 43b obtained in the first piezoelectric film forming process and the second piezoelectric film obtained in the second piezoelectric film forming process. Since it is continuous in the film thickness direction and delamination hardly occurs, a highly reliable piezoelectric film 43 can be obtained.

FIG. 8 is a diagram showing the result of measuring the X-ray diffraction pattern of the piezoelectric film formed by changing the average film thickness of the seed titanium layer formed on the lower electrode. 8A shows the case where the seed titanium layer has an average thickness of 0.5 nm, FIG. 8B shows the case where the seed titanium layer has an average thickness of 1 nm, and FIG. 8C shows the case where the seed titanium layer has an average thickness of 2 nm. FIG. 8D shows the case where the seed titanium layer has an average thickness of 3 nm. The pressure in the sputtering apparatus was 4.0 Pa, the sputtering power was 50 W, and the substrate temperature was 100 ° C. The seed titanium layer formed here has a required sputtering time T in which a continuous film can be formed by the sputtering apparatus used and a sputtering time for forming a desired seed titanium layer thickness Lx based on the film thickness L at that time. Tx Tx = T × Lx / L
Thus, the sputtering time is determined and formed.

  As shown in FIGS. 8C and 8D, when the thickness of the seed titanium layer is 2 nm or more, the 100-plane orientation degree of PZT is not high, and a peak of 111 plane is also observed. On the other hand, as shown in FIGS. 8A and 8B, when the average thickness of the seed titanium layer is 1 nm or less, the degree of orientation in the 100 plane is extremely high, and PZT having the degree of orientation in the 100 plane of almost 100% is obtained. I was able to.

In this embodiment, since the thickness of the seed titanium layer is as extremely thin as 0.1 μm to 1 μm, the Ti element from the seed titanium layer is included in the composition of the piezoelectric film when the piezoelectric film is formed on the seed titanium layer. Even if it gets in, there is very little. Therefore, the raw material composition at the time of forming the piezoelectric film may be matched with the composition of the target piezoelectric film, and it is not necessary to consider the amount of Ti element that enters the piezoelectric film from the seed titanium layer. For example, when PZT of Pb (Zr _0.56 Ti _0.44 ) O ₃ is formed as a piezoelectric film by the sol-gel method, the Zr / Ti ratio of the sol to be adjusted may be 56/44. It is not necessary to lower the ratio of this.

(Upper electrode forming film forming step: S7)
Next, an upper electrode forming film 44a is formed on the piezoelectric film 43 by electron beam evaporation or sputtering. The upper electrode forming film 44a is formed with a film thickness of about 50 nm using platinum, iridium, or other metal.

(Piezoelectric film and upper electrode forming step: S8)
Next, the piezoelectric film 43 and the upper electrode forming film 44a are patterned into a predetermined shape of the piezoelectric element 300 to be formed. Specifically, after a resist material is spin-coated on the upper electrode formation film 44a, patterning is performed in accordance with a position where the pressure generation chamber 12 is to be formed. The upper electrode formation film 44a and the piezoelectric film 43 are etched by ion milling or the like using the remaining resist material as a mask. The piezoelectric element 300 is formed by the above process.

(Strip electrode forming step: S9)
Next, a narrow band electrode 55 that conducts the upper electrode 44 and the wiring electrode 33b is formed. The material of the thin strip electrode 55 is preferably made of gold having low rigidity and low electrical resistance, but aluminum, copper, etc. are also suitable. The thin strip electrode 55 is formed with a film thickness of about 0.2 μm, and then patterned so that the conductive portion between each upper electrode 44 and the wiring electrode 33b remains.

(Pressure generation chamber forming step: S10)
Next, anisotropic etching using an active gas such as anisotropic etching or parallel plate type reactive ion etching is performed on the other surface of the flow path forming substrate 10 on which the piezoelectric element 300 is formed to generate pressure. A chamber 12 is formed. A portion left without being etched becomes a partition wall 22 (see FIG. 5).

(Nozzle plate bonding step: S11)
Finally, the nozzle plate 20 is bonded to the channel forming substrate 10 after etching with an adhesive. At the time of bonding, the nozzle openings 21 are aligned so as to be arranged in the respective spaces of the pressure generating chambers 12. The flow path forming substrate 10 to which the nozzle plate 20 is bonded is attached to the head case 230 to complete the ink jet recording head 220.

  In the present embodiment, the case where the diffusion prevention film 52 is made of a zirconium oxide film has been described. Further, it may be composed of other materials such as titanium oxide, and an additive or the like may be added if desired.

In the present embodiment, the case where the piezoelectric film 43 is formed of lead zirconate titanate (PZT) has been described. However, the present invention is not limited to this, and the piezoelectric film 43 is a crystal of piezoelectric ceramics. In addition to a ferroelectric piezoelectric material such as lead zirconate titanate (PZT), a metal oxide such as niobium oxide, nickel oxide or magnesium oxide may be added thereto. In addition, the composition of the piezoelectric film 43 is appropriately selected in consideration of the characteristics, application, etc. of the piezoelectric element. Specifically, lead titanate (PbTiO ₃ ), lead zirconate titanate (Pb (Zr, Ti) O ₃ ), lead lanthanum titanate ((Pb, La), TiO ₃ ), lead lanthanum zirconate titanate ((Pb, La) (Zr, Ti) O ₃ ) or magnesium zirconium niobate lead zirconate titanate (Pb (Zr, Ti) (Mg, Nb) O ₃ ) is preferably used. In addition, a film having excellent piezoelectric characteristics can be obtained by appropriately adding niobium (Nb) to lead titanate or lead zirconate.

  In the present embodiment, an ink jet recording head that discharges ink droplets as a liquid ejecting head has been described as an example of a printer that includes an ink jet recording head as a liquid ejecting apparatus. The present invention is intended for all liquid ejecting apparatuses having a wide liquid ejecting head. Examples of the liquid ejecting head include a recording head used in an image recording apparatus such as a printer, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an organic EL display, and an electrode formation such as an FED (surface emitting display). Electrode material ejecting heads used in manufacturing, bioorganic matter ejecting heads used in biochip production, and the like.

1 is a perspective view showing a printer according to an embodiment. FIG. 2 is an exploded perspective view of an ink jet recording head used in the printer shown in FIG. 1. FIG. 3 is an enlarged plan view of the vicinity of a piezoelectric actuator of the ink jet recording head shown in FIG. 2. It is sectional drawing along the ii line shown in FIG. It is sectional drawing along the ii-ii line | wire shown in FIG. It is process drawing which shows the manufacturing method of the piezoelectric actuator and inkjet recording head concerning this Embodiment. It is process drawing which shows the manufacturing method of the piezoelectric actuator and inkjet recording head concerning this Embodiment. It is a figure which shows the result of having changed the average film thickness of the seed titanium layer formed on a lower electrode into various films, and having measured the X-ray-diffraction pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Printer, 10 ... Channel formation board | substrate, 12 ... Pressure generation chamber, 33 ... Lower electrode, 43 ... Piezoelectric film, 44 ... Upper electrode, 50 ... Vibration Plate: 51 ... Oxide film, 52 ... Diffusion prevention film, 53 ... Adhesion region, 220 ... Inkjet recording head, 300 ... Piezoelectric element

Claims (10)

A step of forming a lower electrode on the substrate, a step of forming a seed titanium layer on the lower electrode by a sputtering method, a step of forming a piezoelectric film on the seed titanium layer, and an upper portion on the piezoelectric film A method of manufacturing a piezoelectric actuator comprising a step of forming an electrode,
The method for manufacturing a piezoelectric actuator, wherein a sputtering time in the step of forming the seed titanium layer is 2% or more and 20% or less of a required sputtering time for forming a continuous titanium film by a sputtering apparatus used in the sputtering method. In claim 1,
The method for manufacturing a piezoelectric actuator, wherein the pressure in the sputtering apparatus in the step of forming the seed titanium layer is 2 Pa or more and 5 Pa or less. In claim 1 or claim 2,
The method for manufacturing a piezoelectric actuator, wherein sputtering power in the step of forming the seed titanium layer is 50 W or more and 100 W or less. In any one of Claims 1 thru | or 3,
The method for manufacturing a piezoelectric actuator, wherein a sputtering time in the step of forming the seed titanium layer is not less than 1 second and not more than 12 seconds. In any one of Claims 1 thru | or 4,
A method for manufacturing a piezoelectric actuator, wherein, in the step of forming the seed titanium layer, the seed titanium layer is formed to an average thickness of 0.1 nm to 1 nm. In any one of Claims 1 to 5,
The method for manufacturing a piezoelectric actuator, wherein the piezoelectric film is made of PZT or a solid solution mainly composed of PZT. Forming a piezoelectric actuator by the manufacturing method according to any one of claims 1 to 6;
Forming a pressure generating chamber whose internal volume changes due to mechanical displacement of the piezoelectric actuator;
Forming a discharge port that discharges droplets in communication with the pressure generation chamber.   The piezoelectric actuator manufactured by the manufacturing method as described in any one of Claims 1 thru | or 6.   A liquid ejecting apparatus comprising: the piezoelectric actuator according to claim 8; a pressure generating chamber whose internal volume changes due to mechanical displacement of the piezoelectric actuator; and a discharge port that communicates with the pressure generating chamber and discharges droplets. head. A liquid ejecting apparatus comprising: the liquid ejecting head according to claim 9; and a driving device that drives the liquid ejecting head.

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