JP2013065634A - Manufacturing method of electromechanical conversion film, electric conversion film manufactured by the same, electromechanical conversion element, droplet discharge head, and droplet discharging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the quality of an electromechanical conversion film by suppressing heat diffusion of a bottom electrode to increase heating efficiency of a film of a sol gel liquid.SOLUTION: An insulator film 202, disposed between a Si substrate 201 and a bottom electrode film 203, prevents heat of the bottom electrode film 203 generated by being heated by laser beam irradiation from conducting to the Si substrate 201. Almost all the heat of the bottom electrode film 203 conducts only to a PZT precursor film 204 coated on the bottom electrode film 203. Thus, the PZT precursor film 204 can be heated to a desired temperature.

Description

  The present invention relates to a method for manufacturing an electromechanical conversion film, an electromechanical conversion film manufactured by the manufacturing method, an electromechanical conversion element, a droplet discharge head, and a droplet discharge apparatus.

  Conventionally, an electromechanical conversion element configured such that an electromechanical conversion film is sandwiched between electrodes includes, for example, a liquid discharge head that discharges ink droplets, and forms an image by adhering ink droplets to a sheet while conveying a medium. Used in an ink jet recording apparatus. The medium here is also referred to as “paper”, but the material is not limited, and a recording medium, a recording medium, a transfer material, a recording paper, and the like are also used synonymously. The image forming apparatus means an apparatus for forming an image by discharging a liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics. The image formation is not only giving an image having a meaning such as a character or a figure to the medium but also giving an image having no meaning such as a pattern to the medium (simply ejecting a droplet). Also means. The ink is not limited to so-called ink, and is not particularly limited as long as it becomes liquid when ejected. For example, the ink is a generic term for liquids including DNA samples, resists, pattern materials, and the like. Use.

  The ink jet recording apparatus mainly includes a nozzle that discharges ink droplets, a discharge chamber that communicates with the nozzle, a liquid chamber called a pressurized liquid chamber, a pressure chamber, and an ink flow path chamber, and ink in the liquid chamber. And pressure generating means for discharging. As this pressure generating means, there is known a piezo-type pressure generating means for discharging ink droplets by deforming and displacing a vibration plate forming the wall surface of the discharge chamber using an electromechanical conversion element such as a piezoelectric element. . The electromechanical conversion element used for this piezoelectric type pressure generating means is formed by laminating a lower electrode, an electromechanical conversion layer, and an upper electrode. Individual electromechanical conversion elements are arranged to generate ink discharge pressure in each pressure chamber. The electromechanical conversion layer is formed by performing the process of forming the electromechanical conversion film a plurality of times. For example, lead zirconate titanate (PZT) is used as the electromechanical conversion film, and these are generally referred to as metal composite oxides because they contain a plurality of metal oxides as main components.

  The electromechanical conversion film manufacturing method includes a sputtering method, a sol-gel method, a CVD method, a laser ablation method, and the like. The method is excellent in controllability of the crystal state. As a method for producing an electromechanical conversion film using this sol-gel method, the one described in Patent Document 1 is known. In the manufacturing method of Patent Document 1, platinum (Pt) serving as a lower electrode has high wettability, and the surface of the lower electrode becomes a lyophilic surface having lyophilic properties. Then, a platinum film is formed on the Si substrate, and a solution containing the PZT component is applied to the surface of the platinum. The surface on which the PZT solution is applied has poor wettability and becomes a lyophobic surface having lyophobic properties. Then, a photoresist formed in a predetermined pattern by photolithography is placed on the applied PZT solution film, and etching according to the predetermined pattern of the photoresist is performed. Specifically, the PZT solution film that has been exposed without being covered with the photoresist by oxygen plasma irradiation or UV light irradiation is removed, and the PZT solution film that has been coated with the photoresist remains. . Thereafter, the photoresist used for the processing is removed, and the patterning of the PZT solution film covered with the photoresist is completed. By performing the above steps, surface modification is performed so that the surface other than the predetermined portion to which the PZT liquid on the lower electrode is applied is made lyophobic.

  Next, a droplet of a sol-gel liquid containing a raw material for forming an electromechanical conversion film is dropped from a nozzle of a droplet discharge head onto a predetermined portion on the lower electrode from which the PZT solution film has been removed by the etching. A coating process is performed. Then, a heat treatment process by laser light irradiation is performed in which only the sol-gel liquid film dropped on the predetermined portion is scanned while being irradiated with laser light to perform heat treatment at a predetermined temperature. Specifically, the base substrate on which the sol-gel liquid film is formed is fixed, and the laser beam is irradiated so that the spot outer ring portion of the laser light is along the film end of the sol-gel liquid formed on a predetermined portion. Scan while. Alternatively, by placing the base substrate on the XY axis moving stage and moving the XY axis moving stage in the X axis direction-Y axis direction, the predetermined portion on the lower electrode is relatively moved to the fixed laser beam irradiation position. Irradiate with scanning. In this heat treatment step by laser light irradiation, when a predetermined portion of the sol-gel liquid film is irradiated with laser light, a part of the laser light is irradiated to the lower electrode through the sol-gel liquid film. Thereby, the film of the sol-gel solution is heated by heating by laser light irradiation and heat conduction from the lower electrode. The sol-gel solution film is dried, pyrolyzed and crystallized to form an electromechanical conversion film having a laminated structure. The heat treatment step by laser light irradiation here includes a step of drying the sol-gel solution, a step of thermally decomposing the dried sol-gel solution film, and a step of crystallizing the pyrolyzed sol-gel solution film. It is out.

  However, in the method of manufacturing the electromechanical conversion film of Patent Document 1, since the lower electrode is heated by irradiating a part of the laser light to the lower electrode, the heat of the heated lower electrode is the film of the sol-gel solution. In addition to the heat transfer, it also diffuses into the Si substrate immediately below the lower electrode. For this reason, the temperature of the lower electrode cannot be raised to a desired temperature, the heating of the sol-gel solution film becomes insufficient, and the Si substrate may be damaged by the heat transfer of the lower electrode. Therefore, there is a problem that the quality of the electromechanical conversion film is deteriorated.

  The present invention has been made in view of the above problems, and its purpose is to improve the quality of the electromechanical conversion film by suppressing the heat diffusion of the lower electrode and increasing the heating efficiency of the sol-gel liquid film. An electromechanical conversion film manufacturing method, an electroconversion film manufactured by the manufacturing method, an electromechanical conversion element, a droplet discharge head, and a droplet discharge device are provided.

  In order to achieve the above object, the invention of claim 1 includes a film forming step of forming a metal film to be a lower electrode on a substrate, and a sol-gel solution containing a component of an electromechanical conversion film on the metal film. In the method of manufacturing an electromechanical conversion film, which includes: a coating process for coating; and a heat treatment process for heating the metal film with a laser beam irradiated from a laser light source to perform a heat treatment on the film of the sol-gel solution. An insulating film having a lower thermal conductivity than the metal film is formed on the substrate, and the metal film is formed on the insulating film.

  In the present invention, the insulating film provided between the substrate and the metal film prevents the heat of the metal film due to being heated by laser light irradiation from being transmitted to the substrate. For this reason, the heat of the metal film is transmitted only to the sol-gel liquid film coated on the metal film. Thereby, the film | membrane of a sol-gel liquid can be heated to desired temperature. Therefore, the film of the sol-gel solution can be sufficiently heated and the quality of the electromechanical conversion film can be improved by preventing damage to the substrate.

  According to the present invention, it is possible to improve the quality of the electromechanical conversion film by suppressing the heat diffusion of the lower electrode and increasing the heating efficiency of the electromechanical conversion film.

It is a schematic block diagram which shows the example of 1 structure of the droplet discharge apparatus of embodiment of this invention. It is a schematic perspective view of the droplet discharge device of the present embodiment. It is process sectional drawing which shows the manufacturing process of the electromechanical conversion element accompanying formation of the electromechanical conversion film which concerns on this embodiment. It is a characteristic view which shows the hysteresis curve of P (polarization) -E (electric field strength). It is a schematic block diagram which shows one structural example of the droplet discharge head comprised using the electromechanical conversion element manufactured with the manufacturing method. FIG. 6 is a schematic configuration diagram illustrating a configuration example in which a plurality of liquid ejection heads of FIG. 5 are arranged. It is process sectional drawing which shows the manufacturing process of the electromechanical conversion film of this embodiment. It is process sectional drawing which shows another manufacturing process of the electromechanical conversion film of this embodiment. 1 is a perspective view showing a configuration of a droplet discharge coating apparatus equipped with a droplet discharge head according to an embodiment. It is the schematic which shows the outline | summary which performs laser irradiation of the area | region equivalent to a pattern shape. It is sectional drawing which shows the modification of the electromechanical conversion film of this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing a configuration example of a droplet discharge apparatus according to an embodiment of the present invention. FIG. 2 is a schematic perspective view of the droplet discharge device of this embodiment. An ink jet recording apparatus 100 as an example of the droplet discharge apparatus of the present invention shown in both figures mainly includes a carriage 101 that can move in the main scanning direction inside the recording apparatus main body, and the present invention mounted on the carriage 101. The printing mechanism unit 104 is configured to include a recording head 102 including an inkjet head, which is an example of a liquid droplet ejection head manufactured as described above, and an ink cartridge 103 that supplies ink to the recording head 102. In addition, a sheet feeding cassette 106 capable of stacking a large number of sheets 105 can be detachably attached to the lower part of the apparatus main body from the front side, and a manual feed tray 107 for manually feeding sheets 105 is provided. The paper 105 fed from the paper feed cassette 106 or the manual feed tray 107 can be taken in, and a required image is recorded by the printing mechanism 104, and then discharged to a paper discharge tray 108 mounted on the rear side. Make paper.

  The printing mechanism unit 104 holds a carriage 101 slidably in the main scanning direction by a main guide rod 109 and a sub guide rod 110 which are guide members horizontally mounted on left and right side plates (not shown). (Y), cyan (C), magenta (M), and black (Bk) ink droplets are ejected from a recording head 102, which is an example of a droplet ejection head according to the present invention that ejects ink droplets of each color. Outlets (nozzles) are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet ejection direction facing downward. In addition, each ink cartridge 103 for supplying ink of each color to the recording head 102 is replaceably mounted on the carriage 101. The ink cartridge 103 has an air port that communicates with the atmosphere upward, a supply port that supplies ink to the recording head 102 below, and a porous body filled with ink inside. The ink supplied to the recording head 102 by the force is maintained at a slight negative pressure.

  Further, although the heads of the respective colors are used here as the recording heads 102, a single head having nozzles for ejecting ink droplets of the respective colors may be used. Here, the carriage 101 is slidably fitted to the main guide rod 109 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the sub guide rod 110 on the front side (upstream side in the paper conveyance direction). doing. In order to move and scan the carriage 101 in the main scanning direction, a timing belt 114 is stretched between a driving pulley 112 and a driven pulley 113 that are rotationally driven by a main scanning motor 111, and the timing belt 104 is moved to the carriage 101. The carriage 101 is reciprocally driven by forward and reverse rotations of the main scanning motor 111.

  On the other hand, in order to convey the paper 105 set in the paper feed cassette 106 to the lower side of the recording head 102, the paper feed roller 115 and the friction pad 116 for separating and feeding the paper 105 from the paper feed cassette 106 and the paper 105 are guided. A guide member 117 that rotates, a conveyance roller 118 that reverses and conveys the fed paper 105, a conveyance roller 119 that is pressed against the peripheral surface of the conveyance roller 118, and a feeding angle of the sheet 105 from the conveyance roller 118. A tip roller 120 is provided. The transport roller 118 is rotationally driven by a sub-scanning motor 121 through a gear train. A printing receiving member 122 is provided as a paper guide member that guides the paper 105 fed from the transport roller 118 on the lower side of the recording head 102 corresponding to the movement range of the carriage 101 in the main scanning direction. A conveyance roller 123 and a spur 124 that are rotationally driven to send the paper 105 in the paper discharge direction are provided on the downstream side of the printing receiving member 122 in the paper conveyance direction, and the paper 105 is further delivered to the paper discharge tray 108. A roller 125 and a spur 126, and guide members 127 and 128 that form a paper discharge path are disposed.

  At the time of recording, the recording head 102 is driven in accordance with the image signal while moving the carriage 101, thereby ejecting ink onto the stopped paper 105 to record one line. Record the line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 105 has reached the recording area, the recording operation is terminated and the paper 105 is discharged.

  Further, a recovery device 129 for recovering the ejection failure of the recording head 102 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 101. The recovery device 129 includes a cap unit, a suction unit, and a cleaning unit. The carriage 101 is moved to the recovery device 129 side during printing standby, and the recording head 102 is capped by the capping means, and the ejection port portion is kept in a wet state to prevent ejection failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and stable ejection performance is maintained.

  As described above, since the ink jet recording apparatus is equipped with the ink jet head of the present embodiment, there is no ink droplet ejection failure due to vibration plate drive failure, stable ink droplet ejection characteristics are obtained, and image quality is improved. .

  Next, the manufacturing process of the electromechanical conversion film according to the embodiment of the present invention will be described. In this embodiment, an electromechanical conversion element having a transverse vibration (bend mode) type electromechanical conversion film using deformation of the piezoelectric constant d31 will be described as an example. The present invention is an electromechanical conversion film of this type. It is applicable without being limited to.

  When the electromechanical conversion film is a PZT film, a PZT precursor solution synthesized using lead acetate trihydrate, isopropoxide titanium, and normal butoxide zirconium as starting materials can be used. The crystal water of lead acetate is dissolved in methoxyethanol and then dehydrated. The lead amount is 10 [mol%] excess with respect to the stoichiometric composition. This is to prevent crystallinity deterioration due to so-called lead loss during heat treatment. It is possible to synthesize PZT precursor solution by dissolving isopropoxide titanium and normal butoxide zirconium in methoxyethanol, proceeding with alcohol exchange reaction and esterification reaction, and uniformly mixing with methoxyethanol solution in which lead acetate is dissolved. it can. The PZT concentration of this PZT precursor solution is, for example, 0.1 [mol / l].

  The PZT precursor solution in the case where the electromechanical conversion film is a PZT film is prepared by dissolving lead acetate, zirconium alkoxide, and titanium alkoxide compounds described in Non-Patent Document 1 as starting materials and dissolving them in methoxyethanol as a common solvent. Alternatively, a uniform solution may be obtained. The PZT precursor solution is also called “sol-gel solution”.

PZT is a solid solution of lead zirconate (PbZrO ₃ ) and lead titanate (PbTiO ₃ ), and the characteristics differ depending on the ratio. In general, the composition exhibiting excellent piezoelectric characteristics has a ratio of PbZrO ₃ and PbTiO ₃ of 53:47. When expressed by a chemical formula, Pb (Zr0.53, Ti0.47) O ₃ , generally PZT (53/47) It is indicated. The starting materials for lead acetate, zirconium alkoxide and titanium alkoxide compounds are weighed according to this chemical formula. Since the metal alkoxide compound is easily hydrolyzed by moisture in the atmosphere, an appropriate amount of a stabilizer such as acetylacetone, acetic acid or diethanolamine may be added to the precursor solution as a stabilizer.

  Examples of composite oxides other than PZT include barium titanate. In this case, it is also possible to prepare a barium titanate precursor solution by dissolving barium alkoxide and a titanium alkoxide compound in a common solvent. is there.

  Further, when obtaining a patterned PZT film as an electromechanical conversion film on the surface of the first electrode on the base substrate, a coating film is formed by applying the above solution as a coating liquid by a droplet discharge method. A patterned PZT film can be obtained by performing heat treatments of solvent drying, thermal decomposition, and crystallization. Since transformation from the coating film to the crystallized film involves volume shrinkage, it is preferable to obtain a film thickness of 100 [nm] or less in one step in order to obtain a crack-free film. And it is preferable to adjust so that a precursor density | concentration may be optimized from the relationship between the film-forming area of an electromechanical conversion film, and the application quantity of a PZT precursor solution. Further, when used as an electromechanical conversion element of a droplet discharge device, the thickness of the PZT film is required to be 1 [μm] to 2 [μm]. In order to obtain this film thickness, the process is repeated ten times or more.

  Further, in the case of forming a patterned electromechanical conversion layer by the sol-gel method, the PZT precursor solution in which the wettability of the base substrate is controlled is separately applied. This utilizes the phenomenon of alkanethiol self-arranged on a specific metal shown in Non-Patent Document 2, and first, a SAM (Self assembled monolayer) film of thiol on the surface of the platinum group metal of the substrate. Form. Since the alkyl group is arranged on the SAM film, it becomes lyophobic. This SAM film can be patterned using a photoresist by, for example, well-known photolithography etching. Since the patterned SAM film remains even after the resist is peeled off, this portion is lyophobic. On the other hand, the portion from which the SAM film has been removed is lyophilic because the platinum surface is exposed. Using this surface energy contrast, the PZT precursor solution can be applied separately. In the present embodiment, after the SAM film is selectively formed in a region where the PZT precursor solution is not applied, as shown below, the droplet discharge method can reduce the consumption of the PZT precursor solution. The PZT precursor solution is selectively applied by coating (inkjet coating).

FIG. 3 is a process cross-sectional view illustrating a manufacturing process of an electromechanical conversion element accompanied with formation of an electromechanical conversion film according to an embodiment of the present invention. A platinum electrode made of a platinum group metal (not shown) as a first electrode excellent in reactivity with thiol is formed on the surface (upper surface) of the substrate 11 shown in FIG. Yes. A SAM film 12 is formed on the surface of the platinum electrode of the substrate 11 as shown in FIG. The SAM film 12 can be obtained by dipping the substrate 11 in an alkanethiol solution and making it self-align. In this example, an alkanethiol solution obtained by dissolving alkanethiol molecules of CH ₃ (CH ₂ ) —SH in a general organic solvent (alcohol, acetone, toluene, etc.) at a predetermined concentration (for example, several [mol / l]). Was used. After immersing the substrate 11 in this alkanethiol solution and taking it out after a predetermined time, the SAM film 12 can be formed on the surface of the platinum electrode by replacing and washing excess molecules with a solvent and drying. Next, as shown in (c) of the figure, a photoresist 13 is patterned by photolithography, and dry etching (for example, oxygen plasma irradiation or UV light irradiation) is performed as shown in (d) of the figure. Then, the SAM film 12 is removed, and the photoresist 13 used for processing is removed, and the patterning of the SAM film 12 is completed. The SAM film 12 formed in this manner has a contact angle with respect to pure water of, for example, 92 degrees and exhibits lyophobic properties. On the other hand, the surface of the platinum electrode of the substrate 11 exposed by removing the SAM film 12 has a contact angle with pure water of, for example, 54 degrees and exhibits lyophilicity.

  Next, after performing the steps shown in FIGS. 3A to 3D, a droplet discharge method in which the droplets of the PZT precursor solution are discharged from the nozzles, specifically, the PZT precursor by the droplet discharge head 14 is used. The body solution 15 is applied (see (e) of FIG. 3). The application of the PZT precursor solution 15 is performed such that the PZT film 16 is not formed on the SAM film that is a lyophobic part, and the PZT film is formed only on the lyophilic part from which the SAM film has been removed. Finally, the electromechanical conversion film 17 is obtained by performing heat treatments such as solvent drying, thermal decomposition, and crystallization (see (f) of FIG. 3).

  In the method of FIG. 3, the heat treatments of PZT precursor solution application, solvent drying, thermal decomposition, and crystallization are performed once by (a) to (d) of FIG. As shown in the case of obtaining an electromechanical conversion film having a film thickness, (a) to (d) of FIG. 3 above, (e) of FIG. 3 of application of the PZT precursor solution by the droplet discharge method, and solvent drying, 3 (f) of the thermal decomposition and crystallization heat treatments are repeatedly performed a predetermined number of times (two or more times) to form thin electro-mechanical conversion films in multiple layers, and the electric film having a predetermined thickness is formed. A mechanical conversion film may be obtained. In this case, generation of cracks in the electromechanical conversion film can be prevented more reliably.

  Further, in the method of FIG. 3 described above, the surface modification other than the predetermined portion on which the PZT precursor solution on the first electrode is applied is made a lyophobic surface by the SAM film. When the surface is a lyophobic surface, surface modification may be performed so that the surface of a predetermined portion to which the PZT precursor solution on the first electrode is applied becomes a lyophilic surface.

The manufacturing process described above was repeated 15 times to obtain a film of 500 [nm]. No defects such as cracks occurred in the film produced at this time. Further, selective application of the PZT precursor and laser irradiation were performed 15 times to perform crystallization treatment. Defects such as cracks did not occur in the film. The film thickness reached 1000 [nm]. An upper electrode (platinum) was formed on this patterned film, and electrical characteristics and electromechanical conversion ability (piezoelectric constant) were evaluated. As a result, a hysteresis curve of P (polarization) -E (electric field strength) in FIG. 4 was obtained. The relative dielectric constant of the film is 1220, the dielectric loss is 0.02, the remanent polarization is 19.3 [μC / cm ² ], and the coercive electric field is 36.5 [kV / cm], which is equivalent to a normal ceramic sintered body It was found that it has the characteristics of In addition, the electromechanical conversion ability was calculated by measuring the amount of deformation by applying an electric field with a laser Doppler vibrometer and fitting it by simulation. The piezoelectric constant d31 was 120 [pm / V], which was also the same value as the ceramic sintered body. This value is a characteristic value that can be sufficiently designed as a piezoelectric element for use in a liquid discharge head. As an electrode film, an electrode film can be formed in the same manner as the piezoelectric layer by dissolving an oxide such as platinum, SrRuO _3, or LaNiO ₃ in a solvent, applying the ink by an inkjet method, and irradiating with a laser.

  FIG. 5 is a schematic configuration diagram showing a configuration example of a droplet discharge head configured using the electromechanical conversion element manufactured by the manufacturing method. In the illustrated example, a diaphragm 30, an adhesion layer 41, and a lower electrode (first electrode) 42 are stacked on a silicon substrate 20 serving as a liquid chamber substrate, and a predetermined on the lower electrode (first electrode) 42 is formed. The electromechanical conversion element (PZT element) 43 and the upper electrode 44 having the same performance as that of bulk ceramics can be patterned and formed on the portion by the simple manufacturing method described above. Thereafter, the liquid chamber 22a is formed from the back surface (the lower surface in the drawing) of the silicon substrate 20 by an etching removal process, and the nozzle plate 22 having the nozzle holes 21 is joined, whereby the droplet discharge head 50 can be manufactured. . In the figure, descriptions of the liquid supply means, the flow path, and the fluid resistance are omitted. Further, a plurality of the droplet discharge heads 50 shown in FIG. 5 can be arranged as shown in FIG.

A method for manufacturing an electromechanical conversion film by the sol-gel method according to this embodiment will be described.
FIG. 7 is a process cross-sectional view illustrating the manufacturing process of the electromechanical conversion film of this embodiment. As shown in FIG. 2A, first, an insulating film 202 such as SiO ₂ and a platinum (Pt) -based lower electrode film 203 are sequentially formed on a Si substrate 201 by sputtering. Then, as shown in FIG. 4B, the lower electrode film 203 on the outer peripheral portion for patterning the electromechanical conversion film is partially removed in the thickness direction by photolithography etching. Next, as shown in FIG. 3C, a sol-gel solution of a PZT precursor is applied by spin coating and dried at 120 ° C. to form a PZT precursor film 204. As shown in (d) of the same figure, the laser beam 205 is irradiated to the irradiation range which is a part which forms an electromechanical conversion film. As a result, the sol-gel film absorbs and heats the light, and the bottom Pt lower electrode film 203 is heated, and the PZT precursor film 204 is crystallized. Thereafter, as shown in FIG. 5E, when the PZT precursor film 204 that has not been crystallized with dilute hydrochloric acid is etched, only the crystallized portion remains and an electromechanical conversion film 206 is formed. By repeating this, an electromechanical conversion film having a film thickness of 5 [μm] can be obtained. If the wavelength of the laser beam used is 400 [nm] or more, and the shape of the electromechanical conversion film is a rectangular parallelepiped, it is preferable that the spot diameter is substantially equal to any width of the planar shape. Since the laser irradiation region is insulated from the non-laser irradiation region, the lower electrode film 203 is efficiently heated, and the heat from the lower electrode film 203 is thermally conducted to dry, thermally decompose, and crystallize the PZT precursor. can do.

FIG. 8 is a process cross-sectional view showing another manufacturing process of the electromechanical conversion film of this embodiment. The manufacturing process shown in the figure is an electromechanical conversion film manufacturing process according to the present embodiment including a substrate surface modification process. The same reference numerals as those in FIG. 7 denote the same components. As shown in FIG. 2A, first, an insulating film 202 such as SiO ₂ and a platinum (Pt) -based lower electrode film 203 are sequentially formed on a Si substrate 201 by sputtering. Then, as shown in FIG. 5B, the lower electrode film 203 on the outer peripheral portion for patterning the electromechanical conversion film is partially removed by photolithography etching. Next, as shown in FIG. 5C, the SAM film 207 is obtained by dipping the lower electrode film 203 in an alkanethiol solution and self-aligning. This was used _CH 3 _(CH 2) -SH. Since alkanethiol is self-aligned only on the metal, it is not formed in the portion where SiO ₂ is exposed. As shown in FIG. 4D, the portion of the SAM film 207 where the PZT is to be formed is removed, and the photoresist 208 is patterned by photolithography in order to protect the necessary portion of the SAM film 207. Then, as shown in (e) of the figure, for example, by irradiating the substrate surface with oxygen plasma 209, the SAM film 107 for forming the PZT is removed as shown in (f) of the figure. Thereafter, the photoresist 208 is peeled off. As shown in (g) and (h) of the figure, a PZT precursor sol-gel solution is applied and dried at 120 ° C. to form a PZT precursor film 204. As shown to (i) of the figure, the laser beam 205 is irradiated to the irradiation range which is a part which forms an electromechanical conversion film. As a result, the sol-gel film absorbs and heats the light, and the bottom Pt lower electrode film 203 is heated, and the PZT precursor film 204 is crystallized. Thereafter, an electromechanical conversion film 206 is formed as shown in FIG. The contact angle of the SAM film 207 formed by this process with respect to pure water is 92.2 degrees, indicating lyophobic properties, and the contact angle of Pt on the substrate from which the SAM film 207 has been removed is 5.4 degrees, which is lyophilic. It becomes. In this embodiment, the example in which the SAM film 207 is removed by the oxygen plasma 209 has been described, but laser irradiation such as ultraviolet rays may be performed.

FIG. 9 is a perspective view showing the configuration of a droplet discharge coating apparatus equipped with the droplet discharge head of this embodiment. According to the droplet discharge coating apparatus 60 shown in FIG. 9 equipped with the droplet discharge head of this embodiment, the Y-axis drive means 62 is installed on the gantry 61, and the substrate 63 is mounted thereon. The stage 64 is installed so that it can be driven in the Y-axis direction. The stage 64 is provided with suction means such as vacuum and static electricity (not shown), and the substrate 63 is fixed. An X-axis driving means 66 is attached to the X-axis support member 65, and a head base 68 mounted on the Z-axis driving means 67 is attached to the X-axis support member 65, so that it can move in the X-axis direction. ing. A liquid droplet ejection head 69 for ejecting liquid is mounted on the head base 68. Liquid (PZT precursor solution) is supplied to the droplet discharge head 69 from a liquid tank (not shown) through a supply pipe 70. Further, a laser head (not shown) is disposed adjacent to the droplet discharge head 69, and performs driving synchronized with the droplet discharge head 69 by sharing the X-axis drive means. As shown in FIG. 7H, when the PZT precursor solution is applied by the droplet discharge head 69 of FIG. 9, the PZT pattern reaches the region of the insulating film 202 such as SiO ₂ where the SAM film 207 is not formed. After spreading, drying and crystallization are performed by the laser beam 205. The laser irradiation area at this time has a diameter of 30 microns, and the entire surface of the pattern was irradiated by scanning. Region heated by the laser beam 205 is an insulating film 202 such as SiO ₂ serves as a heat insulating layer is efficiently heated becomes coated area under the island-like Pt region. Further, the SAM film 207 formed other than the PZT pattern portion is damaged at 200 ° C. or higher, but is not damaged because the heating region is only the PZT pattern portion. Therefore, it is possible to form an electromechanical conversion film having a predetermined film thickness in a predetermined region only by repeating application of the PZT precursor solution and laser irradiation.

The insulating film used in this embodiment is SiO ₂ , but the material is not limited. However, the greater the difference in thermal conductivity with Pt, the better the efficiency, and SiO ₂ was 7 [W / M · ° C.] and 1/10 of Pt 70 [W / M · ° C.]. The film thickness at that time was 1 [μm] for SiO _{2 and} 0.2 [μm] for Pt. The solution used was lead acetate trihydrate, isopropoxide titanium, and normal butoxide zirconium as starting materials. Crystal water of lead acetate was dissolved in methoxyethanol and then dehydrated. The lead amount is 10 [mol%] excess with respect to the stoichiometric composition. This is to prevent crystallinity deterioration due to so-called lead loss during heat treatment. PZT precursor solution was synthesized by dissolving isopropoxide titanium and normal butoxide zirconium in methoxyethanol, proceeding with alcohol exchange reaction and esterification reaction, and mixing with methoxyethanol solution in which lead acetate was dissolved. The PZT concentration was 0.1 [mol / l]. The film thickness obtained by one film formation is preferably 100 [nm], and the precursor concentration is optimized from the relationship between the film formation area and the amount of applied precursor. Due to the contact angle contrast, the precursor solution spreads only in the hydrophilic part and forms a pattern. This was treated as a first heating (solvent drying) at 120 ° C., and then the organic substance was thermally decomposed to obtain a film thickness of 90 [nm]. This heating step is performed by laser irradiation. Here, the spot diameter of the semiconductor laser having a wavelength of 980 [nm] is wider than the width for forming the PZT. Subsequently, the PZT precursor is applied by an inkjet coating apparatus. The film thickness at this time was 180 [nm]. The LaNiO ₃ is heated by laser irradiation to indirectly dry the PZT precursor. Here, the light absorption rate of LaNiO ₃ with respect to the wavelength of 980 [nm] is about 60%, and the light absorption rate of Pt is about 20%. The water film is not removed. The film thickness of the PZT precursor after drying was 90 [nm]. These steps were repeated 6 times to obtain a film having a thickness of 540 [nm], followed by thermal decomposition treatment. Defects such as cracks did not occur in the film. Furthermore, selective application and drying of the PZT precursor 6 times were performed, and crystallization treatment was performed by laser irradiation. Defects such as cracks did not occur in the film. The film thickness reached 1000 [nm]. In the heating process using these lasers, the SAM film was not removed, and the contact angle with water was maintained at 90 ° or more until the end. Then, the SAM film was removed by hot plate heating, and an upper electrode (platinum) was formed on the PZT patterned film, and electrical characteristics and electro-mechanical conversion ability (piezoelectric constant) were evaluated.

  In addition, by setting the laser irradiation region for crystallization of the PZT film to the same shape as the PZT pattern formation region, the rate of temperature rise during heating of the PZT is increased, and the film quality can be improved. FIG. 10 shows a schematic diagram for performing laser irradiation in an area equivalent to the pattern shape. In this embodiment, the optical system of the laser light source 300 is designed so as to be an irradiation area equivalent to a 0.05 × 1 [mm] PZT pattern, and the pattern portion is formed by opening and closing the shutter while moving in the pattern arrangement direction. Only a portion of the PZT precursor film 204 was irradiated with laser light, and high-speed processing was realized. The laser beam may be scanned without opening and closing the shutter. Further, as shown in FIG. 11 as a modification of the present embodiment, a conductive film 210 is formed on the substrate 201 as a connection method of the lower electrode 203, and the conductive film 210 and the lower electrode 203 are formed as through holes. The connection part 211 is electrically connected. As a result, the lower electrodes 203 are electrically connected in common. In this case, if the connection area of the connection portion with the lower electrode 203 is made as small as possible, it is possible to minimize the heat of the lower electrode 203 from being transmitted to the conductive film 210 via the connection portion 211.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
In the film forming step, an insulating film having a lower thermal conductivity than the metal film is formed on the substrate, and the metal film is formed on the insulating film. According to this, as described in the above embodiment, the insulating film 202 provided between the Si substrate 201 and the lower electrode film 203 receives heat from the lower electrode film 203 due to heating by laser light irradiation. Transmission to the Si substrate 201 is prevented. Then, almost all the heat of the lower electrode film 203 is transmitted only to the PZT precursor film 204 applied on the lower electrode film 203. Thereby, the PZT precursor film 204 can be heated to a desired temperature. Therefore, the quality of the electromechanical conversion film can be improved by sufficiently heating the electromechanical conversion film.
(Aspect B)
In (Aspect A), a portion of the metal film corresponding to the outer peripheral portion of the sol-gel solution is etched in the thickness direction, and the insulating film is exposed from the etched portion. According to this, as described in the above embodiment, the heat of the lower electrode film 203 due to the heating is transmitted to the PZT precursor film 204 also through the outer peripheral portion of the lower electrode film 203. Thereby, the PZT precursor film 204 can be efficiently heated to a desired temperature. Therefore, the quality of the electromechanical conversion film can be improved by sufficiently heating the electromechanical conversion film.
(Aspect C)
(Aspect A) or (Aspect B) includes a step of selectively forming a liquid repellent film on the metal film, and in the coating step, a sol-gel liquid is selectively discharged onto the metal film by a droplet discharge head. According to this, as described in the above embodiment, the component solution of the electromechanical conversion film can be applied to a predetermined portion.
(Aspect D)
In any one of (Aspect A) to (Aspect C), the coating process and the heat treatment process are repeated to produce an electromechanical conversion film having a desired film thickness. According to this, as described in the above embodiment, the quality of the multi-layer electromechanical conversion film can be improved by improving the quality of the electromechanical conversion film in one layer, and the electric film having a reliable and desired film thickness can be improved. A mechanical conversion film can be provided.
(Aspect E)
In (Aspect A), the thermal conductivity of the insulating film is 1/10 or less of the thermal conductivity of the metal film. According to this, as described in the above embodiment, it is possible to prevent the heat of the lower electrode film 203 from being heated by the laser light irradiation from being transmitted to the Si substrate 201.
(Aspect F)
In (Aspect B), the irradiation diameter of the laser light emitted from the laser light source is substantially the same as the width of the exposed portion of the insulating film. According to this, as described in the above embodiment, it is only necessary to simply irradiate laser light, and a highly accurate laser light source and scanning device are not required, and the manufacturing cost can be kept low.
(Aspect G)
Using the method for producing an electromechanical conversion film according to any one of (Aspect A) to (Aspect F), an insulating film and a metal film are sequentially formed on a substrate, and the components of the electromechanical conversion film are formed on the metal film. The sol-gel liquid contained was applied, and the metal film was heated by laser light irradiated from a laser light source to heat-treat the sol-gel liquid. According to this, as explained about the above-mentioned embodiment, a high quality electromechanical transducer can be manufactured.
(Aspect H)
Another metal film serving as an upper electrode is disposed so as to sandwich the electromechanical conversion film of (Aspect G). According to this, as explained about the above-mentioned embodiment, a high quality electromechanical transducer can be manufactured.
(Aspect I)
The electromechanical transducer of (Aspect H) is provided. According to this, as described in the above embodiment, a high-quality liquid droplet ejection head can be manufactured.
(Aspect J)
The droplet discharge head of (Aspect I) is provided. According to this, as described in the above embodiment, it is possible to provide a droplet discharge device capable of performing stable discharge performance.

50 Liquid droplet ejection head 60 Liquid droplet ejection coating apparatus 100 Inkjet recording apparatus 201 Si substrate 202 Insulating film 203 Lower electrode film 204 PZT precursor film 205 Laser light 206 Electromechanical conversion film 207 SAM film 208 Photoresist 209 Oxygen plasma 210 Conductivity Membrane 211 Connection 300 Laser light source

JP 2008-187302 A JP 2006-309995 A

K. D. Budd, S.M. K. Day and D.D. A. Payne, Proc. Brit. Ceram. Soc. 36, 107 (1985) A. Kumar and G.K. M.M. Whitesides, Appl. Phys. Lett. 63, 2002 (1993)

Claims (10)

A film forming process for forming a metal film serving as a lower electrode on the substrate, a coating process for applying a sol-gel liquid containing a component of an electromechanical conversion film on the metal film, and laser light emitted from a laser light source In a method for producing an electromechanical conversion film, comprising a heat treatment step of heating a metal film to heat-treat the sol-gel solution film,
In the film forming step, an insulating film having a lower thermal conductivity than the metal film is formed on the substrate, and the metal film is formed on the insulating film. Method. In the manufacturing method of the electromechanical conversion film according to claim 1,
A method of manufacturing an electromechanical conversion film, comprising etching the metal film at a portion corresponding to an outer peripheral portion of the sol-gel liquid in a thickness direction to expose the insulating film from the etched portion. In the manufacturing method of the electromechanical conversion film according to claim 1 or 2,
An electromechanical conversion comprising: a step of selectively forming a liquid repellent film on the metal film, wherein the sol-gel liquid is selectively discharged onto the metal film by a droplet discharge head in the application step. A method for producing a membrane. In the manufacturing method of the electromechanical conversion film according to any one of claims 1 to 3,
An electromechanical conversion film manufacturing method comprising manufacturing the electromechanical conversion film having a desired film thickness by repeating the coating step and the heat treatment step. In the manufacturing method of the electromechanical conversion film according to claim 1,
The method of manufacturing an electromechanical conversion film, wherein the thermal conductivity of the insulating film is 1/10 or less of the thermal conductivity of the metal film. In the manufacturing method of the electromechanical conversion film according to claim 2,
A method for producing an electromechanical conversion film, wherein an irradiation diameter of laser light emitted from the laser light source is substantially the same as a width of an exposed portion of the insulating film.   Using the method for manufacturing a thin film manufacturing apparatus according to claim 1, the insulating film and the metal film are sequentially formed on a substrate, and an electromechanical conversion film component is contained on the metal film. An electromechanical conversion film produced by applying a sol-gel liquid to be applied, heating the metal film with a laser beam irradiated from a laser light source, and subjecting the sol-gel liquid to a heat treatment.   An electromechanical conversion element, wherein another metal film serving as an upper electrode is disposed so as to sandwich the electromechanical conversion film according to claim 7.   A droplet discharge head comprising the electromechanical conversion element according to claim 8.   A droplet discharge apparatus comprising the droplet discharge head according to claim 9.

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