JP2009054657A - Method of manufacturing dielectric film, method of manufacturing piezoelectric element, and method of manufacturing liquid jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a dielectric film, by which the dielectric film having superior crystallinity can be formed, and to provide a method of manufacturing a piezoelectric element and a method of manufacturing a liquid jet head. <P>SOLUTION: The method of manufacturing the dielectric film is characterized by including a step of forming a dielectric precursor film 71 being a PZT precursor film on one surface side of a substrate 110 made of a silicon single-crystal substrate. A dielectric film 72 is formed by irradiating the substrate 110 with light having a wavelength spectrum peak in a 8 to 12 μm band and by heating and firing the dielectric precursor film 71 for crystallization, using: a chamber 201 in which a wafer 110 for flow passage forming substrate is mounted; and an irradiation means 202 provided outside the chamber 201 in an area opposed to a surface of the wafer 110 for flow passage forming substrate on the opposite side from a surface where the dielectric precursor film 71 is provided to irradiate the substrate with infrared rays. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a dielectric film manufacturing method for manufacturing a dielectric film on a substrate made of a silicon single crystal substrate, a piezoelectric element manufacturing method, and a liquid ejecting head manufacturing method for ejecting liquid from nozzle openings.

  A piezoelectric element used as a pressure generating unit in a liquid ejecting head or the like is an element in which a dielectric film made of a piezoelectric material exhibiting an electromechanical conversion function is sandwiched between two electrodes. The dielectric film is, for example, a crystallized piezoelectric element. It is made of a functional ceramic.

  As a liquid ejecting head using such a piezoelectric element, for example, a part of a pressure generating chamber communicating with a nozzle opening for ejecting ink droplets is constituted by a vibration plate, and the vibration plate is deformed by the piezoelectric element and pressure is applied. There is an ink jet recording head that pressurizes ink in a generation chamber and ejects ink droplets from nozzle openings. Examples of the ink jet recording head include those using a piezoelectric actuator in a flexural vibration mode that flexes and deforms a piezoelectric element. As the one using the flexural vibration mode, for example, a piezoelectric layer made of a uniform dielectric film is formed over the entire surface of the diaphragm by a film forming technique, and this piezoelectric layer is formed into a pressure generating chamber by a lithography method. A device in which a piezoelectric element is formed so as to be independent for each pressure generating chamber by cutting into corresponding shapes is known.

  A so-called sol-gel method is known as a method for producing a piezoelectric layer (dielectric film) constituting a piezoelectric element. That is, a step of forming a precursor film of a piezoelectric layer by applying an organic metal compound sol on a substrate on which a lower electrode is formed and drying and gelling (degreasing) is performed at least once. And crystallize by heat treatment (firing). A piezoelectric layer (dielectric film) having a predetermined thickness is manufactured by repeating these steps a plurality of times.

  A so-called MOD (Metal-Organic Decomposition) method is known as a method for manufacturing a piezoelectric layer (dielectric film) constituting a piezoelectric element. That is, generally, a colloidal solution obtained by dissolving an organometallic compound such as a metal alkoxide in alcohol and adding a hydrolysis inhibitor or the like to this is applied onto the object, and then dried and fired. Thus, a piezoelectric layer (dielectric film) can be manufactured.

  In the dielectric film manufacturing method using the sol-gel method, the MOD method, or the like, the dielectric precursor film is heated by irradiating infrared rays when the dielectric precursor film is heated and fired for crystallization. Infrared heating devices have been used.

JP 2003-115619 A (Claims, page 5, FIG. 6)

  However, when the dielectric film is heated and baked using an infrared heating device, most of the infrared light is absorbed by the dielectric precursor film and directly heats the dielectric precursor film. For this reason, the starting point of the crystallization of the dielectric precursor film is in the surface of the dielectric precursor film (on the side opposite to the base substrate side) or in the film of the dielectric precursor film. Grows independently without inheriting crystallinity such as orientation on the substrate side, crystal grain size, etc., while a columnar crystal is standing, large crystals with independent crystal grains are formed, and the piezoelectric layer There is a problem in that a dielectric film having poor crystallinity that affects the piezoelectric characteristics such as the displacement characteristics is formed.

  In addition, when a sol is heated and degreased, a method of manufacturing a piezoelectric element that irradiates infrared rays including a wavelength of 3 to 5 μm from the substrate side has been proposed (see, for example, Patent Document 1). Then, only infrared light having a wavelength that is easily absorbed by the sol is used, and only the infrared wavelength used in the degreasing process of the sol is defined. Therefore, in the manufacturing method of Patent Document 1, nothing is mentioned about the wavelength of the baking step of crystallizing the dielectric film by heating and baking, and the dielectric film having poor crystallinity is formed for the reasons described above. There is a problem of end.

  If a dielectric film having poor crystallinity is formed, the liquid ejecting characteristics of a liquid ejecting head represented by an ink jet recording head using the dielectric film are deteriorated, and excellent liquid ejecting characteristics can be obtained. There is a problem that you can not.

  In view of such circumstances, an object of the present invention is to provide a dielectric film manufacturing method, a piezoelectric element manufacturing method, and a liquid jet head manufacturing method capable of forming a dielectric film having excellent crystallinity. To do.

An aspect of the present invention that solves the above problems includes a step of forming a dielectric precursor film on one side of a substrate made of a silicon single crystal substrate, and irradiating the substrate with light having a wavelength spectrum peak in the 8 to 12 μm band. The dielectric precursor film may be crystallized by heating and baking the dielectric precursor film.
In such an aspect, the dielectric precursor film itself is directly irradiated by irradiating light in a wavelength region with a high absorption rate of the substrate made of a silicon single crystal substrate and with a low absorption rate of the dielectric precursor film. Without heating, the substrate serving as the base of the dielectric precursor film can be heated. This allows the dielectric precursor film to grow from the base side without crystal growth starting from the inside of the dielectric precursor film, and crystals such as orientation and crystal grain size from the base side. Therefore, the dielectric film can be formed with good crystallinity.

  Here, it is preferable to irradiate the substrate with light from at least the other side of the substrate opposite to the one side where the dielectric precursor film is provided. According to this, the substrate can be efficiently heated without directly heating the dielectric precursor film itself.

  Moreover, it is preferable to irradiate the said board | substrate with light from the one surface side in which the said dielectric precursor film | membrane of the said board | substrate was provided, and the other surface side on the opposite side to the said one surface side. According to this, the dielectric precursor film can be heated at a high temperature rising rate, and an excellent crystalline dielectric film can be formed.

  In addition, when irradiating the substrate with light, it is preferable to irradiate the substrate with light excluding a predetermined wavelength region. According to this, since light in a predetermined wavelength region, for example, a wavelength region that is easily absorbed by the dielectric precursor film is excluded and the silicon single crystal substrate is irradiated with light, In addition, the substrate serving as the base of the dielectric film can be reliably heated without crystal growth starting from the surface.

Furthermore, another aspect of the present invention includes a step of forming a lower electrode on the substrate, a step of forming a piezoelectric layer on the lower electrode, and a step of forming an upper electrode on the piezoelectric layer. And the step of forming the piezoelectric layer is a method of manufacturing the dielectric film of the above aspect.
In this aspect, a piezoelectric element having excellent piezoelectric characteristics can be manufactured.

According to another aspect of the present invention, after the piezoelectric element is formed on the substrate by the method for manufacturing a piezoelectric element according to the above aspect, the substrate is anisotropically etched to communicate with a nozzle opening that ejects liquid. In the method of manufacturing a liquid jet head, the pressure generating chamber is formed.
In this aspect, a liquid ejecting head having excellent liquid ejecting characteristics can be manufactured.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view showing a schematic configuration of an ink jet recording head which is an example of a liquid ejecting head according to Embodiment 1 of the present invention. FIG. 2 is a plan view of FIG. FIG.

  As shown in the figure, the flow path forming substrate 10 is composed of a silicon single crystal substrate whose crystal plane orientation is preferentially oriented to the (110) plane, and one surface thereof is previously formed of silicon dioxide with a thickness of 0.5 by thermal oxidation. An elastic film 50 of ˜2 μm is formed.

  In the flow path forming substrate 10, pressure generating chambers 12 partitioned by a plurality of partition walls 11 are arranged in parallel in the width direction (short direction) by anisotropic etching from the other surface side. In addition, an ink supply path 14 and a communication path 15 are partitioned by a partition wall 11 on one end side in the longitudinal direction of the pressure generating chamber 12 of the flow path forming substrate 10. In addition, a communication portion 13 constituting a part of the reservoir 100 serving as an ink chamber (liquid chamber) common to the pressure generation chambers 12 is formed at one end of the communication passage 15. That is, the flow path forming substrate 10 is provided with a liquid flow path including a pressure generation chamber 12, a communication portion 13, an ink supply path 14, and a communication path 15.

  The ink supply path 14 communicates with one end side in the longitudinal direction of the pressure generation chamber 12 and has a smaller cross-sectional area than the pressure generation chamber 12. For example, in the present embodiment, the ink supply path 14 has a width smaller than the width of the pressure generation chamber 12 by narrowing the flow path on the pressure generation chamber 12 side between the reservoir 100 and each pressure generation chamber 12 in the width direction. It is formed with. As described above, in this embodiment, the ink supply path 14 is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path. Further, each communication path 15 communicates with the side of the ink supply path 14 opposite to the pressure generation chamber 12 and has a larger cross-sectional area than the width direction (short direction) of the ink supply path 14. In the present embodiment, the communication passage 15 is formed with the same cross-sectional area as the pressure generation chamber 12.

  In other words, the flow path forming substrate 10 is connected to the pressure generation chamber 12, the ink supply path 14 having a smaller cross-sectional area in the short direction of the pressure generation chamber 12, the ink supply path 14, and the ink supply. A communication passage 15 having a cross-sectional area larger than the cross-sectional area in the short direction of the path 14 is provided by being partitioned by a plurality of partition walls 11.

  Further, on the opening surface side of the flow path forming substrate 10, a nozzle plate 20 having a nozzle opening 21 communicating with the vicinity of the end of each pressure generating chamber 12 on the side opposite to the ink supply path 14 is provided with an adhesive. Or a heat-welded film or the like. The nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, stainless steel, or the like.

On the other hand, an elastic film 50 made of silicon dioxide and having a thickness of, for example, about 1.0 μm is formed on the side opposite to the opening surface of the flow path forming substrate 10. An insulator film 55 made of zirconium oxide (ZrO ₂ ) or the like and having a thickness of, for example, about 0.4 μm is laminated. On the insulator film 55, the lower electrode film 60 having a thickness of about 0.1 to 0.5 μm and lead zirconate titanate (PZT) which is an example of a dielectric film are formed. For example, a piezoelectric layer 70 having a thickness of about 1.1 μm and an upper electrode film 80 made of gold, platinum, iridium, or the like and having a thickness of, for example, about 0.05 μm are laminated and formed by a process described later, so that the piezoelectric element 300 is formed. Is configured. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In addition, here, a portion that is configured by any one of the patterned electrodes and the piezoelectric layer 70 and in which piezoelectric distortion is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion 320. In this embodiment, the lower electrode film 60 is a common electrode of the piezoelectric element 300, and the upper electrode film 80 is an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for the convenience of the drive circuit and wiring. In any case, the piezoelectric active part 320 is formed for each pressure generating chamber 12. In addition, here, the piezoelectric element 300 and the diaphragm that is displaced by driving the piezoelectric element 300 are collectively referred to as an actuator device. In the above-described example, the elastic film 50, the insulator film 55, and the lower electrode film 60 function as a diaphragm. However, the present invention is not limited to this, and for example, the elastic film 50 and the insulator film 55 are provided. Instead, only the lower electrode film 60 may act as a diaphragm. Further, the piezoelectric element 300 itself may substantially serve as a diaphragm.

In addition, as the piezoelectric layer 70 of the present embodiment, a perovskite structure crystal film made of a ferroelectric ceramic material having an electromechanical conversion effect and formed on the lower electrode film 60 can be cited. As a material of the piezoelectric layer 70, for example, a ferroelectric piezoelectric material such as lead zirconate titanate (PZT), or a material obtained by adding a metal oxide such as niobium oxide, nickel oxide, or magnesium oxide to the piezoelectric material is suitable. It is. Specifically, lead titanate (PbTiO ₃ ), lead zirconate titanate (Pb (Zr, Ti) O ₃ ), lead zirconate (PbZrO ₃ ), lead lanthanum titanate ((Pb, La), TiO ₃ ) ), Lead lanthanum zirconate titanate ((Pb, La) (Zr, Ti) O ₃ ) or lead magnesium titanate zirconate titanate (Pb (Zr, Ti) (Mg, Nb) O ₃ ), etc. Can do. In the present embodiment, lead zirconate titanate (PZT) is used as the piezoelectric layer 70.

  Further, each upper electrode film 80 that is an individual electrode of the piezoelectric element 300 is drawn from the vicinity of the end on the ink supply path 14 side and extended to the insulator film 55, for example, from gold (Au) or the like. Lead electrode 90 is connected.

  On the flow path forming substrate 10 on which such a piezoelectric element 300 is formed, a protective substrate 30 having a reservoir portion 31 constituting at least a part of the reservoir 100 is bonded via an adhesive 35. In this embodiment, the reservoir portion 31 is formed across the protective substrate 30 in the thickness direction and across the width direction of the pressure generating chamber 12, and as described above, the reservoir portion 31 is connected to the communication portion 13 of the flow path forming substrate 10. A reservoir 100 is formed which communicates with each other and serves as a common liquid chamber for the pressure generating chambers 12.

  A piezoelectric element holding portion 32 having a space that does not hinder the movement of the piezoelectric element 300 is provided in a region of the protective substrate 30 that faces the piezoelectric element 300. The protective substrate 30 only needs to have a space that does not hinder the movement of the piezoelectric element 300, and the space may be sealed or unsealed.

  As such a protective substrate 30, it is preferable to use substantially the same material as the coefficient of thermal expansion of the flow path forming substrate 10, for example, glass, ceramic material, etc. In this embodiment, the same material as the flow path forming substrate 10 is used. The silicon single crystal substrate was used.

  The protective substrate 30 is provided with a through hole 33 that penetrates the protective substrate 30 in the thickness direction. The vicinity of the end portion of the lead electrode 90 drawn from each piezoelectric element 300 is provided so as to be exposed in the through hole 33.

  Further, a drive circuit 120 for driving the piezoelectric elements 300 arranged in parallel is fixed on the protective substrate 30. For example, a circuit board or a semiconductor integrated circuit (IC) can be used as the drive circuit 120. The drive circuit 120 and the lead electrode 90 are electrically connected via a connection wiring 121 made of a conductive wire such as a bonding wire.

  In addition, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto the protective substrate 30. Here, the sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm), and the sealing film 41 seals one surface of the reservoir portion 31. It has been stopped. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SUS) having a thickness of 30 μm). Since the region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with a flexible sealing film 41. Has been.

  In such an ink jet recording head 1 of the present embodiment, ink is taken in from an external ink supply means (not shown), filled with ink from the reservoir 100 to the nozzle opening 21, and then in accordance with a recording signal from the drive circuit 120. Then, a voltage is applied between each of the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generation chamber 12 to bend and deform the elastic film 50, the insulator film 55, the lower electrode film 60, and the piezoelectric layer 70. As a result, the pressure in each pressure generating chamber 12 increases and ink droplets are ejected from the nozzle openings 21.

  Hereinafter, a method for manufacturing such an ink jet recording head 1 will be described with reference to FIGS. 3 to 4 and FIGS. 6 to 9 are cross-sectional views showing a method for manufacturing an ink jet recording head, and FIG. 5 is a graph showing the relationship between wavelength and emissivity (absorption rate).

First, as shown in FIG. 3A, a silicon dioxide film 51 to be the elastic film 50 is formed on the surface of the flow path forming substrate wafer 110 by thermal oxidation. Next, as shown in FIG. 3B, a zirconium (Zr) layer is formed on the elastic film 50 (silicon dioxide film 51), and then thermally oxidized to form an insulator film 55 made of zirconium oxide (ZrO ₂ ). Form.

  Next, as shown in FIG. 3C, a lower electrode film 60 made of, for example, platinum or iridium is formed over the entire surface of the insulator film 55. The lower electrode film 60 can be formed by, for example, a sputtering method.

  Next, a piezoelectric layer 70 made of lead zirconate titanate (PZT) is formed. Here, in the present embodiment, a so-called sol-gel in which a so-called sol obtained by dissolving and dispersing a metal organic substance in a solvent is applied, dried, gelled, and further fired at a high temperature to obtain a piezoelectric layer 70 made of a metal oxide. The piezoelectric layer 70 is formed using the method. The material of the piezoelectric layer 70 is not limited to lead zirconate titanate, and other piezoelectric materials described above may be used.

  As a specific forming procedure of the piezoelectric layer 70, first, as shown in FIG. 4A, a dielectric precursor film 71 which is a PZT precursor film is formed on the lower electrode film 60. That is, a sol (solution) containing a metal organic compound is applied onto the flow path forming substrate 10 on which the lower electrode film 60 is formed (application process). Next, the dielectric precursor film 71 is heated to a predetermined temperature and dried for a predetermined time (drying step). For example, in the present embodiment, the dielectric precursor film 71 can be dried by holding at 150 to 200 ° C. for 5 to 15 minutes.

Next, the dried dielectric precursor film 71 is degreased by heating it to a predetermined temperature and holding it for a certain time (degreasing step). For example, in this embodiment, the dielectric precursor film 71 is degreased by heating to a temperature of about 300 to 400 ° C. and holding it for about 5 to 10 minutes. The degreasing referred to here is to release the organic component contained in the dielectric precursor film 71 as, for example, NO ₂ , CO ₂ , H ₂ O or the like.

  Next, as shown in FIG. 4B, the dielectric precursor film 71 is crystallized by being heated to a predetermined temperature and held for a predetermined time to form a dielectric film 72 (firing process).

  Specifically, the flow path forming substrate wafer 110 is irradiated with light having a wavelength spectrum peak in the 8 to 12 μm band, and the flow path forming substrate wafer 110 that is the base of the dielectric precursor film 71 is heated. The dielectric precursor film 71 is heated from the base side and baked to form the dielectric film 72.

  Here, the relationship between the wavelength and the absorptance (emissivity) of the flow path forming substrate wafer 110 made of a silicon single crystal substrate and the dielectric precursor film 71 will be described. 5A is a graph showing the relationship between the wavelength of silicon and the emissivity (absorption rate), and FIG. 5B shows the relationship between the wavelength and emissivity of the dielectric precursor film made of PZT. It is a graph which shows a relationship.

  As shown in FIG. 5 (a), silicon has a light absorption rate (emissivity) of 0.2 or more for light having a wavelength spectrum peak in the 8 to 12 μm band. Therefore, the flow path forming substrate wafer 110 made of a silicon single crystal substrate can be efficiently heated in a short time by light having a wavelength spectrum peak in the 8 to 12 μm band.

  On the other hand, as shown in FIG. 5B, the dielectric precursor film of the above-described material has the slightest difference between materials, but it absorbs light most at the wavelength spectrum peak in the 13 to 15 μm band, particularly the 14 μm band. In other regions, that is, light having a wavelength spectrum peak in the 8 to 12 μm band with good silicon absorption shown in FIG. 5A, the light absorption is low.

  Therefore, when the dielectric precursor film 71 is heated by irradiating the light having a wavelength spectrum peak in the 8 to 12 μm band to the flow path forming substrate wafer 110, the dielectric precursor film 71 has a wavelength region other than the wavelength region having a high absorption rate. The substrate of the dielectric precursor film 71, that is, the flow path forming substrate wafer 110 can be heated without directly heating the dielectric precursor film 71 with light in the wavelength region, and the dielectric precursor film 71 can be heated. The crystal growth of the dielectric precursor film 71 can be started from the base side without crystal growth starting from the film. As a result, the dielectric film 72 can be formed with good crystallinity by taking over crystallinity such as orientation and crystal grain size from the base side. That is, the dielectric film 72 having a desired film thickness can be formed with a relatively small grain size and a uniform crystal without prescribing the film thickness of the dielectric film 72, thereby substantially forming a large crystal. Can be prevented. Thereby, the piezoelectric element 300 having the dielectric film 72 having excellent crystallinity can be formed, and the displacement characteristics of the piezoelectric element 300 can be improved.

  The graph shown in FIG. 5A is described in “Establishment of Spectroscopy” (Ohm) by Keiei Kudo, and the graph shown in FIG. 5B is measured by experiment. It is the result. Further, the dielectric precursor film 71 heated by the light having the spectral peak in the above-described wavelength band is the one before crystallization to form the dielectric film 72, that is, the dielectric precursor film 71 after the degreasing step. That's it.

  Moreover, the irradiation of light having such a predetermined wavelength spectrum peak can be performed by the heating means 200 shown in FIG. Specifically, the heating unit 200 includes a chamber 201 in which the flow path forming substrate wafer 110 is placed inside, and a dielectric precursor film 71 of the flow path forming substrate wafer 110 provided outside the chamber 201. And an irradiating means 202 for irradiating infrared rays, provided in a region opposite to the surface opposite to the provided surface.

  The chamber 201 is used for heating the dielectric precursor film 71 in an oxygen atmosphere, with the flow path forming substrate wafer 110 placed therein.

  The irradiating means 202 is provided so as to irradiate the surface opposite to the surface on which the dielectric precursor film 71 of the flow path forming substrate wafer 110 placed in the chamber 201 is provided.

  Examples of such irradiation means 202 include a glow lamp obtained by sintering silicon carbide (SiC) into a rod shape, an arc lamp using carbon C as a radiation material, a lamp using stainless steel as a radiation material, and a lamp using ceramics as a radiation material. Etc. can be used. In addition, the radiation wavelength irradiated from a global lamp is 1-50 micrometers, and the radiation wavelength irradiated from an arc lamp is 2-25 micrometers. Moreover, the radiation wavelength irradiated from the lamp | ramp which uses stainless steel as a radiation raw material is 4-10 micrometers.

  Then, the light irradiated from the irradiation unit 202 is irradiated to the flow path forming substrate wafer 110 as light having a wavelength spectrum peak in the 8 to 12 μm band described above using, for example, a filter that cuts off a predetermined wavelength. You can do it.

  In this embodiment, the chamber 201 is formed of calcium fluoride so that a wavelength of 9 μm or more is not transmitted through the chamber 201. Incidentally, if the chamber is formed of quartz that is generally used, the chamber made of quartz cannot transmit light having a wavelength of 5 μm or more. In this embodiment, by using the chamber 201 made of calcium fluoride, the wavelength of 9 μm or more of the light irradiated from the irradiation means 202 by the chamber 201 is blocked, and only the wavelength smaller than 9 μm is transmitted into the chamber 201. ing. Of course, by appropriately selecting the material of the chamber 201, it is possible to prevent light having a wavelength of 12 μm or more from being transmitted. For this reason, the chamber 201 can block light having a wavelength spectrum peak in the 13 to 15 μm band, which has a high absorption rate of the dielectric precursor film 71, and prevents the dielectric precursor film 71 from being directly heated. be able to. Incidentally, in order to cut off a wavelength smaller than 8 μm, a filter that absorbs a predetermined wavelength region may be provided between the chamber 201 and the irradiation means 202 as described above. An absorption film that absorbs a wavelength region smaller than 8 μm may be formed so that the chamber 201 itself functions as a filter.

  By heating the dielectric precursor film 71 (channel-forming substrate wafer 110) using such a heating means 200, light in a wavelength region that is easily absorbed by the dielectric precursor film 71 can be blocked. Therefore, even if the light irradiated from the irradiation unit 202 includes many wavelengths that are easily absorbed by the dielectric precursor film 71, the dielectric precursor film 71 is not substantially heated directly.

  In such a firing step of the dielectric film 72, it is preferable to heat the dielectric precursor film 71 to 600 to 750 ° C. In this embodiment, the heating means 200 described above heats at 700 ° C. for 5 minutes. The dielectric precursor film 71 was baked to form a dielectric film 72. In the firing step, the rate of temperature rise is preferably 50 ° C./sec or more, and preferably 100 ° C./sec or more. In this way, by setting the temperature rising rate during firing of the dielectric film 72 to 50 ° C./sec or more, the dielectric film 72 can be performed in a shorter time as compared with the case where the temperature rising rate is low for a long time, and the dielectric film. 72 can be formed of uniform crystals having a relatively small grain size, and the formation of large crystals can be substantially prevented.

  In addition, also in the drying process and the degreasing process described above, by using the heating means 200 used in the firing process, it is possible to reduce the manufacturing cost by reducing the type of apparatus to be used. An apparatus different from the heating means 200, for example, a hot plate may be used.

  Then, as shown in FIG. 6A, when the first layer of the dielectric film 72 is formed on the lower electrode film 60, the lower electrode film 60 and the first dielectric film 72 are patterned simultaneously. The patterning of the lower electrode film 60 and the dielectric film 72 can be performed by dry etching such as ion milling, for example.

  After the patterning, the dielectric film forming process including the coating process, the drying process, the degreasing process, and the baking process described above is repeated a plurality of times, thereby forming a plurality of dielectric films 72 as shown in FIG. 6B. A piezoelectric layer 70 having a predetermined thickness is formed. For example, when the film thickness per sol is about 0.1 μm, for example, the entire film thickness of the piezoelectric layer 70 composed of the ten dielectric films 72 is about 1.1 μm.

  After the piezoelectric layer 70 is formed, as shown in FIG. 7A, for example, an upper electrode film 80 made of iridium is formed on the entire surface of the flow path forming substrate wafer 110, and then, FIG. ), The piezoelectric layer 300 and the upper electrode film 80 are patterned in a region facing each pressure generating chamber 12 to form the piezoelectric element 300.

  Next, the lead electrode 90 is formed. Specifically, as shown in FIG. 7C, after the lead electrode 90 is formed over the entire surface of the flow path forming substrate wafer 110, for example, each through a mask pattern (not shown) made of a resist or the like. Each piezoelectric element 300 is formed by patterning.

  Next, as shown in FIG. 8A, a protective substrate wafer 130 holding a plurality of patterned piezoelectric elements 300 is bonded onto the flow path forming substrate wafer 110 by, for example, an adhesive 35. The protective substrate wafer 130 is preliminarily formed with a reservoir portion 31, a piezoelectric element holding portion 32, and the like. The protective substrate wafer 130 is made of a silicon single crystal substrate, and the rigidity of the flow path forming substrate wafer 110 is remarkably improved by bonding the protective substrate wafer 130.

  Next, as shown in FIG. 8B, the flow path forming substrate wafer 110 is polished to a certain thickness. Next, as shown in FIG. 8C, for example, a mask film 52 is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, as shown in FIG. 9, the pressure generating chamber 12, the communication portion are formed by anisotropically etching (wet etching) the flow path forming substrate wafer 110 using an alkaline solution such as KOH through the mask film 52. 13, an ink supply path 14 and a communication path 15 are formed.

  Thereafter, the mask film 52 on the surface side where the pressure generating chamber 12 of the flow path forming substrate wafer 110 is opened is removed, and unnecessary portions of the peripheral portions of the flow path forming substrate wafer 110 and the protective substrate wafer 130 are, for example, It is removed by cutting by dicing or the like. The nozzle plate 20 having the nozzle openings 21 formed on the surface of the flow path forming substrate wafer 110 opposite to the protective substrate wafer 130 is bonded, and the compliance substrate 40 is bonded to the protective substrate wafer 130. The ink jet recording head 1 having the above-described structure is manufactured by dividing the flow path forming substrate wafer 110 and the like into a single chip size flow path forming substrate 10 as shown in FIG.

  The ink jet recording head 1 manufactured in this way is provided with the piezoelectric element 300 having the piezoelectric layer 70 on which the dielectric film 72 having excellent crystallinity is laminated. Ink jet recording heads having excellent piezoelectric characteristics such as the above and excellent ink discharge characteristics can be obtained.

(Other embodiments)
Although one embodiment of the present invention has been described above, the basic configuration of the ink jet recording head is not limited to that described above. For example, in Embodiment 1 described above, the lower electrode film 60 made of platinum or iridium is illustrated, but the present invention is not particularly limited thereto. For example, before the dielectric precursor film 71 is formed, the lower electrode film 60 is formed on the lower electrode film 60. You may make it provide seed titanium etc. which become the nucleus at the time of crystal growth of dielectric film 72.

  In the first embodiment described above, the sol-gel method is exemplified as a method for forming the dielectric film 72 constituting the piezoelectric layer 70. However, the present invention is not particularly limited thereto, and for example, the dielectric precursor film 71 is formed. The dielectric film 72 is formed by using PVD (Physical Vapor Deposition) method such as MOD (Metal-Organic Decomposition) method, sputtering method or laser ablation method, and then the dielectric precursor film 71 is heated and fired to be crystallized. May be formed.

  In Embodiment 1 described above, the silicon single crystal substrate having a crystal plane orientation of (110) is exemplified as the flow path forming substrate 10 and the flow path forming substrate wafer 110. However, the present invention is not particularly limited thereto. A silicon single crystal substrate having a (100) crystal plane orientation may be used, or an SOI substrate or the like may be used.

  Furthermore, in the first embodiment described above, the irradiation means 202 is positioned opposite to the other surface of the flow path forming substrate wafer 110 opposite to the one surface on which the dielectric precursor film 71 is provided, that is, the flow direction. Although the other surface of the path forming substrate wafer 110 is provided to irradiate light, the present invention is not particularly limited thereto. For example, the irradiation means 202 is provided with the dielectric precursor film 71 of the channel forming substrate wafer 110. Alternatively, it may be provided so as to irradiate light on one surface side, or may be provided so as to irradiate both one surface and the other surface of the flow path forming substrate wafer 110.

  In the first embodiment described above, the ink jet recording head 1 has been described as an example of the liquid ejecting head. However, the present invention broadly targets all liquid ejecting heads and ejects liquids other than ink. Of course, the present invention can also be applied to a method of manufacturing a liquid jet head. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

  Further, the present invention is not limited to a method for manufacturing a liquid jet head having a piezoelectric element. That is, it goes without saying that the present invention is not limited to a method for manufacturing a piezoelectric layer made of a dielectric film, but can be applied to a method for manufacturing a dielectric film made of any dielectric material.

FIG. 2 is an exploded perspective view illustrating a schematic configuration of the recording head according to the first embodiment. 2A and 2B are a plan view and a cross-sectional view of the recording head according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. 3 is a graph showing a relationship between a wavelength and an absorptance according to Embodiment 1. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Inkjet recording head (liquid jet head), 10 Flow path formation board | substrate, 12 Pressure generation chamber, 13 Communication part, 14 Ink supply path, 20 Nozzle plate, 21 Nozzle opening, 30 Protection board, 31 Reservoir part, 32 Piezoelectric element Holder, 40 compliance substrate, 60 lower electrode film, 70 piezoelectric layer, 71 dielectric precursor film, 72 dielectric film, 80 upper electrode film, 90 lead electrode, 100 reservoir, 110 wafer for flow path forming substrate, 120 Drive circuit, 121 connection wiring, 130 protective substrate wafer, 200 heating means, 201 chamber, 202 irradiation means, 300 piezoelectric element

Claims (6)

  A step of forming a dielectric precursor film on one side of a substrate made of a silicon single crystal substrate; and heating the dielectric precursor film by irradiating the substrate with light having a wavelength spectrum peak in the 8-12 μm band A method for producing a dielectric film, characterized by firing and crystallizing.   2. The dielectric film according to claim 1, wherein the light irradiation to the substrate is performed at least from the other surface side opposite to the one surface side of the substrate on which the dielectric precursor film is provided. Production method.   The light irradiation to the substrate is performed from one surface side of the substrate on which the dielectric precursor film is provided and from the other surface side opposite to the one surface side. 3. A method for producing a dielectric film according to 1 or 2.   4. The method of manufacturing a dielectric film according to claim 1, wherein, when the substrate is irradiated with light, the substrate is irradiated with light excluding a predetermined wavelength region. 5.   Forming a piezoelectric layer, comprising: forming a lower electrode on the substrate; forming a piezoelectric layer on the lower electrode; and forming an upper electrode on the piezoelectric layer. A method for manufacturing a piezoelectric element, wherein the step is a method for manufacturing the dielectric film according to claim 1.   6. The method of manufacturing a piezoelectric element according to claim 5, wherein after the piezoelectric element is formed on the substrate, the substrate is anisotropically etched to form a pressure generating chamber that communicates with a nozzle opening that ejects liquid. A method of manufacturing a liquid ejecting head.

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