JP2016147422A - Liquid jet head, manufacturing method of the same, and liquid jet device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit deterioration of a diaphragm from deteriorating performance of a liquid jet head.SOLUTION: A liquid jet head includes: a diaphragm 50; and a piezoelectric element 300 formed on a second vibration film 52 of the diaphragm 50. The piezoelectric element 300 includes: an active part 320 in which a first electrode 60, a piezoelectric layer 70 covering the first electrode 60, and a second electrode 80 covering the piezoelectric layer 70 are laminated; and a non-active part 330 in which at least one of the piezoelectric layer 70 and the second electrode 80 are disposed. The non-active part 330 has an opening part 53 which exposes the second vibration film 52. The opening part 53 is covered by a protection film 400.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a liquid ejecting head, a method for manufacturing the liquid ejecting head, and a liquid ejecting apparatus including the liquid ejecting head.

  Conventionally, an ink jet printer including a liquid ejecting head is known. The liquid ejecting head includes a flow path forming substrate provided with a pressure chamber, a vibration plate communicating with the pressure chamber, and a piezoelectric element formed on the vibration plate. In the liquid ejecting head, droplets such as ink are ejected (discharged) by vibrating the vibration plate to change the pressure in the pressure chamber. The piezoelectric element includes a portion (active portion) in which a first electrode, a piezoelectric layer, and a second electrode are sequentially stacked on a vibration plate, and a piezoelectric layer and a second electrode are sequentially stacked on the vibration plate. Part (inactive part). A plurality of first electrodes are formed in an island shape, and the piezoelectric layer and the second electrode are formed across the plurality of first electrodes. By applying a signal between the first electrode and the second electrode, the piezoelectric layer of the active part expands and the diaphragm vibrates.

  For example, a liquid ejecting head in which an opening is provided in a second electrode of an inactive portion has been proposed (Patent Document 1). Since the second electrode provided in the inactive part suppresses vibration of the diaphragm, if the opening is provided in the second electrode of the inactive part, the diaphragm is likely to vibrate. Therefore, in the liquid jet head described in Patent Document 1, the displacement amount of the diaphragm is increased, and the droplet discharge amount can be increased.

JP 2010-208138 A

  However, in the liquid ejecting head described in Patent Document 1, if the displacement amount of the diaphragm becomes too large, the diaphragm is cracked, the diaphragm is deteriorated, and the performance of the liquid ejecting head may be lowered.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A liquid jet head according to this application includes a diaphragm and a piezoelectric element formed on a first surface of the diaphragm, and the piezoelectric element includes a first conductive layer, the first conductive layer, and the first conductive layer. An active portion in which a piezoelectric layer covering one conductive layer and a second conductive layer covering the piezoelectric layer are sequentially stacked, and at least one of the piezoelectric layer and the second conductive layer is disposed. A non-active portion, wherein the non-active portion has an opening exposing the first surface, and the opening is covered with a protective film.

  According to this application example, since the diaphragm exposed at the opening is covered (protected) by the protective film, even if the diaphragm is greatly displaced (vibrated), the diaphragm is cracked. Is less likely to occur. In other words, the diaphragm exposed at the opening is protected by the protective film, so that the diaphragm is less likely to be deteriorated, the displacement amount efficiency of the diaphragm is increased, and a highly reliable liquid jet head can be provided.

  Application Example 2 In the liquid jet head according to the application example, it is preferable that the protective film is a resin.

  Since the resin has flexibility, even if the diaphragm is displaced, cracks are hardly generated, and deterioration of the protective film is suppressed.

  Application Example 3 In the liquid jet head according to the application example described above, the diaphragm is disposed on the opposite side of the first member constituting the first surface and the first conductive layer of the first member. It is preferable that the first member exposed at the opening is thinner than the first member not exposed at the opening.

  Displacement of the diaphragm can be increased by thinning the first member exposed at the opening and providing a thinned area on the diaphragm.

  Application Example 4 In the liquid jet head according to the application example described above, the second conductive layer includes a first portion that surrounds the opening and projects from the piezoelectric layer, and a second portion that covers the piezoelectric layer. It is preferable that the protective film is formed so as to cover at least a part of the first portion.

  Since the protective film does not cover the second portion of the second conductive layer, the displacement of the second portion of the second conductive layer is not suppressed.

  Application Example 5 In the liquid jet head according to the application example, the second conductive layer includes a first part that surrounds the opening and projects from the piezoelectric layer, and a second part that covers the piezoelectric layer. The protective film is preferably formed so as to cover at least a part of the first part and the second part.

  Since at least a part of the first portion of the second conductive layer and the second portion of the second conductive layer are covered with the protective film, the first portion of the second conductive layer and the second conductive layer Deterioration of the second part can be suppressed.

  Application Example 6 In the liquid jet head according to the application example described above, it is preferable that the Young's modulus of the protective film is smaller than the Young's modulus of the second conductive layer.

  Since the Young's modulus of the protective film is smaller than the Young's modulus of the second conductive layer, the protective film is more flexible than the second conductive layer and hardly deteriorates even when displaced greatly.

  Application Example 7 In the liquid jet head according to the application example described above, it is preferable that the Young's modulus of the protective film is 10 GPa or less.

  Since the Young's modulus of the protective film is as small as 10 GPa or less, the protective film is excellent in flexibility and hardly deteriorates even when displaced greatly.

  Application Example 8 In the liquid jet head according to the application example, it is preferable that the protective film is a film having a tensile stress.

  When the protective film has a tensile stress, the force for suppressing the displacement of the diaphragm is stronger than when the protective film has a compressive stress.

  Application Example 9 In the liquid jet head according to the application example described above, it is preferable that the protective film has conductivity.

  When the protective film has conductivity, the resistance of the wiring composed of the second conductive layer in the inactive portion can be reduced.

  Application Example 10 A liquid ejecting apparatus according to this application example includes the liquid ejecting head according to the application example.

  Since the liquid ejecting head described in the application example has high reliability, the liquid ejecting apparatus including the liquid ejecting head also has high reliability.

  Application Example 11 A liquid jet head manufacturing method according to this application example is a liquid jet head manufacturing method including a vibration plate and a piezoelectric element formed on a first surface of the vibration plate. The element includes an active portion in which a first conductive layer, a piezoelectric layer, and a second conductive layer are sequentially stacked, and an inactive portion in which at least one of the piezoelectric layer and the second conductive layer is stacked. A step of forming the first conductive layer on the first surface, a step of forming the piezoelectric layer, a step of forming a second conductive layer, and the first portion on the inactive portion. The method includes a step of forming an opening that exposes one surface and a step of forming a protective film that covers the opening with a photosensitive resin material.

  According to the manufacturing method of this application example, since the diaphragm exposed at the opening is covered (protected) by the protective film, even if the diaphragm is greatly displaced (vibrated), the diaphragm Cracks are less likely to occur. In other words, the diaphragm exposed at the opening is protected by the protective film, so that the diaphragm is less likely to be deteriorated, the displacement amount efficiency of the diaphragm is increased, and a highly reliable liquid jet head can be provided.

  Further, since the protective film is formed by a photolithography process using a photosensitive resin material, for example, the process of forming (film forming) the protective film and the process of etching (patterning) the protective film are simplified, and the protective film is formed. The process can be shortened and the productivity of the liquid jet head can be increased.

  Application Example 12 In the method of manufacturing a liquid jet head according to the application example described above, it is preferable that the step of forming the opening includes a step of etching the diaphragm and thinning the diaphragm.

  When the diaphragm is etched to provide a region where the diaphragm is thinned, the displacement of the diaphragm can be increased.

  Application Example 13 In the method of manufacturing a liquid jet head according to the application example described above, in the step of forming the protective film, the protective film is preferably formed across the active portion.

  When the protective film is formed across the active part, the diaphragm of the active part is protected, and it is difficult for the diaphragm of the active part to be deteriorated such as a crack.

FIG. 3 is an exploded perspective view of the liquid ejecting head according to the first embodiment. Sectional drawing of the part by which the flow-path formation board | substrate and the vibration board | substrate are arrange | positioned. 5 is a process flow illustrating a method for manufacturing a liquid jet head according to an embodiment. Sectional drawing which shows the state after passing through the main processes of the process flow shown in FIG. Sectional drawing which shows the state after passing through the main processes of the process flow shown in FIG. Sectional drawing which shows the state after passing through the main processes of the process flow shown in FIG. FIG. 3 is a schematic cross-sectional view of a piezoelectric element according to a second embodiment. FIG. 4 is a schematic cross-sectional view of a piezoelectric element according to a third embodiment. FIG. 6 is a schematic diagram illustrating a configuration of a liquid ejecting apparatus according to a fourth embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. Such an embodiment shows one aspect of the present invention and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. In each of the following drawings, the scale of each layer or each part is made different from the actual scale so that each layer or each part can be recognized on the drawing.

(Embodiment 1)
FIG. 1 is an exploded perspective view of the liquid jet head according to the first embodiment. FIG. 2 is a cross-sectional view of a portion along the line AA ′ in FIG. 1, that is, a portion where the flow path forming substrate and the vibration substrate are arranged.

  As shown in FIG. 1, in the liquid ejecting head 1000, the nozzle plate 20, the flow path forming substrate 10, the vibration substrate 350, and the protective substrate 30 are sequentially stacked.

The nozzle plate 20 has a plurality of nozzle openings 21 and is joined to the flow path forming substrate 10 by an adhesive, a heat welding film, or the like.
In the following description, the direction in which the nozzle openings 21 are arranged is the X direction, and the direction that intersects the X direction is the Y direction. Further, the direction from the nozzle plate 20 toward the protective substrate 30, that is, the thickness direction of the liquid jet head is defined as the Z direction.

The flow path forming substrate 10 includes a partition wall portion 11 and a pressure generation chamber 12. A diaphragm 50 that is a component of the vibration substrate 350 is formed in the Z direction of the pressure generation chamber 12. The vibration plate 50 includes a first vibration film 51 disposed on the upper side of the flow path forming substrate 10 and a second vibration film 52 disposed on the piezoelectric element 300 side. A portion surrounded by at least a part of the first electrode 60, the piezoelectric layer 70, the first vibration film 51, and the second vibration film 52 becomes the pressure generation chamber 12.
The first diaphragm 51 is an example of a “second member”, and the second diaphragm 52 is an example of a “first member”.

  The liquid flow path such as the pressure generating chamber 12 is formed by anisotropically etching the flow path forming substrate 10 from one surface, and the liquid flow path surface such as the pressure generating chamber 12 is vibrated with the flow path forming substrate 10. It is comprised with the board 50 (2nd vibration film 52).

  A vibration substrate 350 is formed in the Z direction of the flow path forming substrate 10. The vibration substrate 350 includes the vibration plate 50 and the piezoelectric element 300.

The diaphragm 50 includes a first diaphragm 51 and a second diaphragm 52. The first vibration film 51 is a film having an elasticity of 0.5 μm, for example. The second vibration film 52 is a film having an elastic insulating property with a thickness of 0.2 μm. A piezoelectric element 300 is formed on the surface of the second vibration film 52 opposite to the first vibration film 51 (the surface on the Z (+) direction side).
The surface of the second vibration film 52 on which the piezoelectric element 300 is formed is an example of a “first surface”.

  The piezoelectric element 300 includes a first electrode 60 having a thickness of approximately 0.2 μm, a piezoelectric layer 70 having a thickness of approximately 1.0 μm, and a thickness of approximately 0.05 μm in the Z direction of the second vibration film 52. The second electrode 80 is sequentially laminated. The first electrode 60 has a shape extending in the Y direction, and a plurality of first electrodes 60 are arranged along the X direction. The piezoelectric layer 70 is formed so as to cover at least a part of the upper surface of the first electrode 60. Like the first electrode 60, the piezoelectric layer 70 has a shape extending in the Y direction and is arranged in a plurality along the X direction. Has been. The second electrode 80 is formed so as to cover the piezoelectric layer 70.

Hereinafter, the piezoelectric element 300 of the vibration substrate 350 will be described in more detail.
As shown in FIG. 2, in the piezoelectric element 300, the portion where the first electrode 60, the piezoelectric layer 70, and the second electrode 80 overlap becomes the active portion 320 (P1), and the portion where the first electrode 60 is not formed. (A portion where at least one of the piezoelectric layer and the second electrode is disposed) becomes the inactive portion 330 (P2). The first electrode 60 constituting the piezoelectric element 300 is divided for each pressure generating chamber 12 and constitutes an individual electrode independent for each piezoelectric element 300. The first electrode 60 is formed with a width narrower than the width of the pressure generating chamber 12. The end of the first electrode 60 in the X direction is located inside the region facing the pressure generation chamber 12. The end portions of the first electrode 60 in the Y direction are extended to the outside of the pressure generation chamber 12, respectively. Although the material of the 1st electrode 60 will not be specifically limited if it is a metal material, For example, platinum (Pt), iridium (Ir), etc. are used suitably.

  Although not shown, the end of the piezoelectric layer 70 in the Y direction is located inside the end of the first electrode 60, and the end of the first electrode 60 in the X direction is formed by the piezoelectric layer 70. Covered. The end of the piezoelectric layer 70 at the end of the pressure generation chamber 12 in the X direction is located on the outer side (the pressure generation chamber 12 side) than the end of the first electrode 60.

  A lead electrode 90 made of, for example, gold (Au) or the like is connected to the first electrode 60 extending to the outside in the Y direction of the piezoelectric layer 70. Although not shown, the lead electrode 90 constitutes a terminal portion to which connection wiring connected to a drive circuit or the like is connected.

  The piezoelectric layer 70 is formed independently for each pressure generating chamber 12. Since the rigidity of the portion (so-called arm portion of the diaphragm 50) facing the X direction end of the pressure generating chamber 12 of the diaphragm 50 is suppressed, the piezoelectric element 300 can be displaced favorably.

  The piezoelectric layer 70 is formed from a crystal film (perovskite crystal) having a perovskite structure made of a ferroelectric ceramic material having an electromechanical conversion effect and formed in the Z direction of the first electrode 60. As the material of the piezoelectric layer 70, for example, a ferroelectric piezoelectric material such as lead zirconate titanate (PZT) or a material added with a metal oxide such as niobium oxide, nickel oxide, or magnesium oxide can be used. . In the present embodiment, lead zirconate titanate (PZT) is used as the piezoelectric layer 70.

  The second electrode 80 is provided continuously on the piezoelectric layer 70 and is configured as a common electrode common to the plurality of piezoelectric elements 300. In the X direction, the end of the second electrode 80 is located outside the end of the piezoelectric layer 70. That is, the end portion of the piezoelectric layer 70 is covered with the second electrode 80. Although the material of the 2nd electrode 80 will not be specifically limited if it is a metal material, For example, iridium (Ir) etc. are used suitably.

  The piezoelectric element 300 is displaced by applying a voltage between the first electrode 60 and the second electrode 80. By applying a voltage between the two electrodes, piezoelectric strain is generated in the piezoelectric layer 70 sandwiched between the first electrode 60 and the second electrode 80. When a voltage is applied to both electrodes, piezoelectric distortion occurs in the piezoelectric layer 70 in the active part 320 (P1), and piezoelectric distortion hardly occurs in the piezoelectric layer 70 in the inactive part 330 (P2).

  In the present embodiment, all of the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are continuously provided to the outside of the pressure generation chamber 12. The active part 320 is continuously provided to the outside of the pressure generation chamber 12.

The second portion 81 of the second electrode 80 disposed in the inactive portion 330 is provided with an opening 53 that exposes the second vibrating membrane 52. In other words, the opening 53 that exposes the surface of the second vibration film 52 on which the piezoelectric element 300 is formed is provided.
The position of the opening 53 may be in the second portion 81 of the second electrode 80 (the arm of the diaphragm 50), and is not particularly limited. The shape of the opening 53 is not particularly limited as long as at least a part of the upper surface of the second vibration film 52 can be exposed.

A portion where the second electrode 80 protrudes from the piezoelectric layer 70 between the opening 53 and the piezoelectric layer 70 becomes a second portion 81 of the second electrode 80. Hereinafter, the second portion 81 of the second electrode 80 is referred to as a second electrode protruding portion 81. The second vibrating membrane 52 exposed through the opening 53 is thinner than the portion of the second vibrating membrane 52 where the opening 53 is not provided.
The second portion 81 (second electrode projecting portion 81) of the second electrode 80 is an example of the “first portion” in the present invention. The portion of the second electrode 80 that covers the piezoelectric layer 70 is an example of a “second portion”.

  The protective film 400 is a resin made of an organic material. The protective film 400 includes at least one selected from, for example, an epoxy resin, a polyimide resin, a silicon resin, and a fluorine resin. In addition, the protective film 400 can be formed by liquid phase film-forming which is solution coating methods, such as a photolithography method, a spin coat method, and a spray method, for example.

  Specifically, the protective film 400 is a resin formed by photolithography using photosensitive polyimide (Young's modulus: about 10 GPa). The protective film 400 is formed so as to protect (cover) at least a part of the opening 53 and the second electrode projecting portion 81. In other words, the opening 53 that exposes the surface of the second vibration film 52 on which the piezoelectric element 300 is formed is covered with the protective film 400.

  The protective film 400 is formed across the second electrode projecting portion 81 and the opening 53, and the thickness of the protective film 400 is about 0.4 μm. By forming the protective film 400 so as to protect at least a part of the opening 53 and the second electrode projecting portion 81, for example, the displacement amount of the diaphragm 50 becomes too large, and the diaphragm 50 is cracked. The problem that 50 deteriorates can be suppressed. That is, providing the protective film 400 makes it difficult for cracks or the like to occur in the diaphragm 50.

Further, the protective film 400 may be a conductive resin (conductive organic material), for example. Examples of the conductive resin include a conductive resin (conductive polymer) including at least one selected from a polythiophene resin, a polyacetylene resin, a polyaniline resin, and a polypyrrole resin. The protective film 400 made of a conductive resin can be formed by, for example, liquid phase film formation that is a solution coating method such as an inkjet method.
Since the protective film 400 has conductivity, the resistance of the second electrode 80 can be reduced.

Further, the protective film 400 is an inorganic film (inorganic material) including at least one of silicon oxide (SiOx), zirconium oxide (ZrOx), tantalum oxide (TaOx), aluminum oxide (AlOx), and titanium oxide (TiOx), for example. There may be. When the protective film 400 is composed of an inorganic film, it is preferable to use, for example, aluminum oxide (AlOx) or alumina (Al ₂ O ₃ ), which is an inorganic amorphous material, as the constituent material of the protective film 400. The protective film 400 made of an inorganic film can be formed by vapor phase film formation such as MOD method, sol-gel method, sputtering method, and CVD method, for example.
When the protective film 400 is made of an inorganic material, the protective film 400 is less likely to deteriorate than when the protective film 400 is made of an organic material, and the reliability of the protective film 400 can be improved.

The protective film 400 is preferably made of a material having a Young's modulus smaller than that of the second electrode 80. That is, the protective film 400 is preferably made of a material having a Young's modulus smaller than about 200 GPa, which is the Young's modulus of the second electrode 80, for example. Specifically, the Young's modulus of the protective film 400 is preferably about 1 GPa or less.
By providing the protective film 400 having a Young's modulus smaller than that of the second electrode 80, the diaphragm 50 and the second electrode 80 of the active part 320 can be protected without hindering the displacement of the active part 320.

  The protective film 400 preferably has a tensile stress as an internal stress. By using the internal stress of the protective film 400 as a tensile stress, the active portion can be convex on the side opposite to the pressure generation chamber 12 to improve the displacement characteristics. Note that the protective film 400 whose internal stress is tensile stress can be formed by vapor phase film formation such as a CVD method, or liquid phase film formation such as a solution coating method such as a spin coating method or a photolithography method.

  The constituent material of the protective film 400 is preferably a material having toughness. If the protective film 400 has toughness, the diaphragm 53 is less likely to be cracked by covering the opening 53 with the protective film 400.

  Although not shown, the liquid ejecting head 1000 according to this embodiment takes in ink from an ink introduction port connected to an external ink supply unit, fills the inside with ink until reaching the nozzle opening 21, and then follows a recording signal from a drive circuit. A voltage is applied between the first electrode 60 and the second electrode 80 corresponding to the pressure generation chamber 12. As a result, the diaphragm 50 is bent and deformed together with the piezoelectric element 300 to increase the pressure in each pressure generating chamber 12, and an ink droplet is ejected from each nozzle opening 21.

FIG. 3 is a process flow showing the method of manufacturing the liquid jet head according to the present embodiment. 4 to 6 are views corresponding to FIG. 2 and are cross-sectional views showing a state after the main steps of the process flow shown in FIG. 3 are performed.
Hereinafter, with reference to FIGS. 3 to 6, a method of manufacturing the liquid jet head according to the present embodiment will be described.

As shown in FIG. 3, the method of manufacturing the liquid jet head according to the present embodiment includes a step of forming the first vibration film 51 (Step S <b> 1), a step of forming the second vibration film 52 (Step S <b> 2), A step of forming the first electrode 60 (step S3), a step of etching the first electrode 60 (step S4), a step of forming the piezoelectric layer 70 (piezoelectric film 74) (step S5), and a piezoelectric body. The step of etching the layer 70 (step S6), the step of forming the second electrode 80 (step S7), the step of etching the second electrode 80 (step S8), and the step of forming the protective film 400 (step S9). ) And.
Steps S3 and S4 are an example of “a step of forming the first conductive layer on the first surface”. Steps S5 and S6 are an example of “a step of forming a piezoelectric layer”. Step S7 is an example of a “step of forming the second conductive layer”. Step S8 is an example of a “step of forming an opening”. Step S9 is an example of a “step of forming a protective film”.

  As shown in FIG. 4A, in step S <b> 1, the first vibration film 51 is formed on the surface of the flow path forming substrate wafer 110. The flow path forming substrate wafer 110 is made of a silicon substrate, and the first vibration film 51 made of silicon dioxide is formed by thermally oxidizing the flow path forming substrate wafer 110 (silicon substrate).

  The constituent material of the first vibration film 51 is not limited to silicon dioxide, and may be a silicon nitride film, a polysilicon film, an organic film (such as polyimide or parylene), or the like. The first vibration film 51 may be formed by a sputtering method, a CVD method, a spin coating method, or the like.

As shown in FIG. 4B, in step S <b> 2, the second vibration film 52 made of zirconium oxide is formed on the first vibration film 51. The second vibration film 52 is not limited to zirconium oxide, but is titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), magnesium oxide (MgO), lanthanum aluminate (LaAlO ₃ ). Etc. may be used. Examples of the method for forming the second vibration film 52 include a sputtering method, a CVD method, and a vapor deposition method.

  As shown in FIG. 4C, in step S3, the first electrode 60 is formed on the entire surface of the second vibration film 52. The constituent material of the first electrode 60 is not particularly limited, but when lead zirconate titanate (PZT) is used as the piezoelectric layer 70, it is desirable that the material has little change in conductivity due to diffusion of lead oxide. For example, platinum, iridium, or the like can be used as a constituent material of the first electrode 60. The 1st electrode 60 can be formed by methods, such as sputtering method and PVD method (physical vapor deposition method), for example.

  As shown in FIG. 4D, in step S4, the first electrode 60 is patterned to have an inclined side surface (tapered side surface). The patterning of the first electrode 60 can be performed by dry etching such as ion milling, for example. Since the 1st electrode 60 functions as an individual electrode of each active part 320, the 1st electrode 60 is completely separated for every active part 320 by Step S4.

  In step S5, the coating process, the drying process, the degreasing process, and the firing process are repeated to form the piezoelectric layer 70 made of lead zirconate titanate (PZT). Specifically, a so-called sol-gel method is used, in which a so-called sol in which a metal complex is dissolved and dispersed in a solvent is applied, dried and gelled, and further fired at a high temperature to form a piezoelectric layer 70 made of a metal oxide. Thus, the piezoelectric layer 70 is formed. The manufacturing method of the piezoelectric layer 70 is not limited to the sol-gel method, and for example, a MOD (Metal Organic Decomposition) method, a PVD (Physical Vapor Deposition) method such as a sputtering method or a laser ablation method may be used. That is, the piezoelectric layer 70 may be formed by either a liquid phase method or a gas phase method.

As a specific procedure for forming the piezoelectric layer 70, a piezoelectric precursor film which is a PZT precursor film is formed.
First, a sol (solution) containing a metal complex is applied onto the flow path forming substrate wafer 110 on which the first electrode 60 (crystal seed layer) is formed. The process of applying this metal complex is an application process. The method for applying the sol is not particularly limited, and examples thereof include a spin coat method using a spin coater and a slit coat method using a slit coater.

  Next, the piezoelectric precursor film is heated to a predetermined temperature and dried for a predetermined time. The step of drying the piezoelectric precursor film is a drying step. In this embodiment, a process of holding the piezoelectric precursor film at 170 to 180 ° C. for 8 to 30 minutes is performed.

Next, the piezoelectric precursor film is degreased by heating to a predetermined temperature and holding for a certain period of time. Degreasing is to release organic components contained in the piezoelectric precursor film as, for example, NO ₂ , CO ₂ , H ₂ O, or the like. The process of degreasing the piezoelectric film 74 is a degreasing process. In this embodiment, the piezoelectric precursor film is heated to a temperature of about 300 to 400 ° C. and held for about 10 to 30 minutes.

  The piezoelectric precursor film is heated to a predetermined temperature, held for a predetermined time, and crystallized to form the piezoelectric film 74. The step of crystallizing the piezoelectric precursor film to form the piezoelectric film 74 is the crystallization step. In the crystallization step, it is preferable that the temperature rising rate is approximately 50 ° C./sec or more and the heat treatment temperature (crystallization temperature) is 650 ° C. or more.

  As a heating device used in the drying step, the degreasing step, and the baking step, for example, a hot plate, an RTP (Rapid Thermal Processing) device that heats by irradiation with an infrared lamp, or the like can be used.

  As shown in FIG. 5A, a piezoelectric film composed of a plurality of layers of piezoelectric films 74 is formed by repeating the process of forming the piezoelectric film 74, which includes the application process, the drying process, the degreasing process, and the baking process, a plurality of times. The body layer 70 is formed. The piezoelectric film 74 is continuously formed over the upper surface and the side surface of the first electrode 60 in the Z direction of the second vibration film 52.

  As shown in FIG. 5B, in step S <b> 6, the piezoelectric layer 70 is patterned in a region facing each pressure generation chamber 12. Specifically, a mask (not shown) formed in a predetermined shape is provided on the piezoelectric layer 70, and the piezoelectric layer 70 is etched through this mask. The piezoelectric layer 70 can be patterned by dry etching such as reactive ion etching or ion milling.

  In step S <b> 7, the second electrode 80 is formed over the piezoelectric layer 70 and the Z direction of the second vibration film 52. As the material of the second electrode 80, platinum (Pt), iridium (Ir), or the like is preferably used. The second electrode 80 can be formed by, for example, a sputtering method or a PVD method (physical vapor deposition method).

  As shown in FIG. 5C, in step S8, the second electrode 80 is patterned into a predetermined shape. Specifically, the second electrode 80 is patterned by dry etching such as reactive ion etching or ion milling, for example, and a second electrode projecting portion 81 projecting from the piezoelectric layer 70 and an opening exposing the second vibration film 52 are exposed. 53, the second electrode 80 is formed.

Further, after the opening 53 is formed, etching for thinning the second vibration film 52 is performed, and the second vibration film 52 exposed in the opening 53 is replaced with the second vibration film in a portion where the opening 53 is not provided. Thinner than 52.
That is, the step of etching the second electrode 80 in step S8 (the step of forming the opening 53) includes a step of etching the second vibration film 52 and thinning the second vibration film 52.

  That is, when patterning the second electrode 80, the second vibration film 52 is continuously etched, and the second vibration film 52 exposed at the opening 53 is thinned without increasing the number of manufacturing steps. The amount of displacement of the diaphragm 50 (piezoelectric element 300) can be increased by reducing the thickness of the second diaphragm 52 exposed at the opening 53.

As shown in FIG. 5D, in step S9, the protective film 400 is formed so as to cover the second electrode projecting portion 81 and the opening 53. That is, the protective film 400 is formed across the active part 320. In this embodiment, the protective film 400 made of an organic material such as photosensitive polyimide is formed by photolithography so as to cover the second electrode projecting portion 81 and the opening 53, and the second film exposed through the opening 53 is formed. The vibration film 52 is protected by the protective film 400.
Since the protective film 400 is formed only by the photolithography process using a photosensitive resin material such as photosensitive polyimide, for example, the film forming process of the protective film 400 and the etching process of the protective film 400 are simplified, and the protective film 400 is formed. Thus, the productivity of the liquid jet head 1000 can be increased.

  As shown in FIG. 6A, after the protective substrate 30 is bonded to the upper surface of the vibration substrate 350, the flow path forming substrate wafer 110 is thinned to a predetermined thickness.

  As shown in FIG. 6B, a mask film is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape.

  As shown in FIG. 6C, anisotropic etching (wet etching) using an alkaline solution such as KOH is performed on the flow path forming substrate wafer 110, so that the pressure generation chamber 12 facing the piezoelectric element 300 is formed. Form.

  Unnecessary portions on the outer peripheral edge of the flow path forming substrate wafer 110 are removed by cutting, for example, by dicing. 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 is bonded to the protective substrate wafer 130. The liquid ejecting head 1000 is formed by dividing the forming substrate wafer 110 and the like into one chip size channel forming substrate 10 and the like as shown in FIG.

According to the present embodiment, the vibration efficiency (displacement amount) of the vibration substrate 350 can be increased by reducing the thickness of the second vibration film 52 exposed at the opening 53. In addition, the diaphragm 50 of the inactive portion 330 can be protected by the protective film 400, and deterioration of the diaphragm 50 such as cracks can be prevented.
Therefore, the liquid jet head 1000 with higher quality and higher reliability can be obtained.

  Further, in the present embodiment, the piezoelectric layer 70 of each piezoelectric element 300 is continuously provided, but the piezoelectric layer 70 is provided independently for each piezoelectric element 300. There may be.

(Embodiment 2)
As mentioned above, although one Embodiment of this invention was described, the basic composition of this invention is not limited to what was mentioned above.

FIG. 7 is a diagram corresponding to FIG. 2 and a schematic cross-sectional view of the piezoelectric element according to the second embodiment.
In the liquid jet head of this embodiment, the shape of the protective film 400 is different from that of the liquid jet head 1000 of the first embodiment. This is the difference between the present embodiment and the first embodiment, and other configurations are the same between the present embodiment and the first embodiment.
Hereinafter, with reference to FIG. 7, the liquid ejecting head according to the present embodiment will be described focusing on differences from the liquid ejecting head 1000 according to the first embodiment. Moreover, about the same component as Embodiment 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

In the first embodiment, the protective film 400 is formed so as to cover (protect) the opening 53 and at least a part of the second electrode projecting portion 81, but is not limited thereto.
As shown in FIG. 7, the protective film 400 covers (protects) the opening 53, the second electrode projecting portion 81, and at least part of the portion of the second electrode 80 that covers the piezoelectric layer 70. To). Furthermore, the protective film 400 is not limited to the one made of an organic material, and the protective film 400 may be made of another material (for example, an inorganic material).

  As in the first embodiment, the opening 53, the second electrode projecting portion 81, and at least a part of the portion of the second electrode 80 that covers the piezoelectric layer 70 are covered (so as to be protected) by photolithography. ), A protective film 400 is formed. Further, the protective film 400 is thicker than the protective film 400 of the first embodiment (about 0.4 μm).

  Compared with the first embodiment, the protective film 400 is formed wider, and the protective film 400 is made thicker, whereby deterioration due to cracks or the like of the diaphragm 50 can be more strongly suppressed.

(Embodiment 3)
FIG. 8 corresponds to FIG. 2 and is a schematic cross-sectional view of the piezoelectric element according to the third embodiment.
In the liquid jet head of the present embodiment, the shape of the protective film 400 is different from the liquid jet head 1000 of the first embodiment and the liquid jet head of the second embodiment. This is the difference between the present embodiment and the first and second embodiments, and the other configurations are the same.

  Hereinafter, with reference to FIG. 8, the liquid ejecting head according to the present embodiment will be described focusing on differences from the liquid ejecting head 1000 according to the first embodiment. Moreover, about the same component as Embodiment 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  As shown in FIG. 8, the protective film 400 is formed so as to protect the entire piezoelectric element 300. That is, as in the first embodiment, the protective film 400 is formed only by the photolithography method, and the protective film 400 is formed so as to protect (cover) the upper surface of the piezoelectric element 300.

  In the present embodiment, the wider protective film 400 is formed as compared with the first and second embodiments, so that deterioration due to cracks or the like of the diaphragm 50 can be further suppressed.

(Embodiment 4)
FIG. 9 is a schematic diagram illustrating a configuration of the liquid ejecting apparatus according to the fourth embodiment.
As shown in FIG. 9, in the liquid ejecting apparatus 2000, the recording head unit 1 (1A, 1B) having the liquid ejecting head 1000 is detachably provided with the ink cartridge 2 (2A, 2B) constituting the ink supply means. ing. A carriage 3 on which the recording head unit 1 is mounted is provided on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. The recording head unit 1 ejects black ink and color ink, for example.

  The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the carriage 3 on which the recording head unit 1 is mounted is moved along the carriage shaft 5. The apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S, which is a recording medium such as paper fed by a not-shown paper feed roller, is wound around the platen 8 and conveyed. It has become so.

  The liquid ejecting apparatus 2000 forms an image on the recording sheet S by ejecting black ink and color ink by the recording head unit 1 and conveying the recording sheet S.

  In the liquid ejecting head 1000, the vibration efficiency (displacement amount) of the vibration substrate 350 is improved and the deterioration of the vibration plate 50 is suppressed, so that the quality and reliability of the liquid ejecting head 1000 are improved. Accordingly, the liquid ejecting apparatus 2000 on which the liquid ejecting head 1000 is mounted can also improve the quality and reliability of the liquid ejecting apparatus 2000. That is, the liquid ejecting apparatus 2000 with improved printing quality and improved durability can be realized.

  In the above-described example, as the liquid ejecting apparatus 2000, the liquid ejecting head 1000 mounted on the carriage 3 and moving in the main scanning direction is illustrated, but the configuration is not particularly limited. The liquid ejecting apparatus 2000 may be, for example, a so-called line type recording apparatus that performs printing by fixing the liquid ejecting head 1000 and moving a recording sheet S such as paper in the sub-scanning direction.

  In the above-described embodiment, the liquid ejecting apparatus 2000 has a configuration in which the ink cartridge 2 that is a liquid storage unit is mounted on the carriage 3. However, the liquid ejection device 2000 is not limited to this. May be fixed to the apparatus main body 4 and the storage means and the liquid jet head 1000 may be connected via a supply pipe such as a tube. Furthermore, the liquid storage means may not be mounted on the liquid ejecting apparatus 2000.

  In the above-described embodiment, the present invention has been described by taking the liquid ejecting head applicable to the liquid ejecting apparatus as an example, but the present invention is widely intended for the entire liquid ejecting head. Examples of the liquid ejecting head include various recording heads used in image recording apparatuses such as printers (liquid ejecting apparatuses), color material ejecting heads used in manufacturing color filters such as liquid crystal displays, organic EL displays, and FEDs. Examples thereof include an electrode material ejection head used for electrode formation such as (field emission display), a bioorganic matter ejection head used for biochip production, and the like.

  Furthermore, the present application is not limited to the piezoelectric element used for the liquid ejecting head, and can be used for other devices. Examples of other devices include an ultrasonic device such as an ultrasonic transmitter, an ultrasonic motor, and a piezoelectric transformer. The present invention can also be applied to a piezoelectric element used as a sensor. Examples of the sensor in which the piezoelectric element is used include an infrared sensor, an ultrasonic sensor, a thermal sensor, a pressure sensor, and a pyroelectric sensor.

  DESCRIPTION OF SYMBOLS 10 ... Channel formation board | substrate, 11 ... Partition, 12 ... Pressure generating chamber, 20 ... Nozzle plate, 21 ... Nozzle opening, 30 ... Protection board, 50 ... Vibrating plate, 51 ... 1st vibrating membrane, 52 ... 2nd vibrating membrane 53 ... Opening, 60 ... first electrode, 70 ... piezoelectric layer, 74 ... piezoelectric film, 80 ... second electrode, 81 ... second electrode overhanging portion, 90 ... lead electrode, 130 ... wafer for protective substrate, DESCRIPTION OF SYMBOLS 300 ... Piezoelectric element, 320 ... Active part, 330 ... Inactive part, 350 ... Vibrating substrate, 400 ... Protective film, 1000 ... Liquid ejecting head, 2000 ... Liquid ejecting apparatus.

Claims (13)

A diaphragm,
A piezoelectric element formed on the first surface of the diaphragm;
Including
The piezoelectric element is
An active portion in which a first conductive layer, a piezoelectric layer covering the first conductive layer, and a second conductive layer covering the piezoelectric layer are sequentially stacked;
An inactive portion in which at least one of the piezoelectric layer and the second conductive layer is disposed;
Have
The inactive portion has an opening that exposes the first surface;
The liquid jet head is characterized in that the opening is covered with a protective film.   The liquid ejecting head according to claim 1, wherein the protective film is a resin. The diaphragm includes a first member that constitutes the first surface, and a second member that is disposed on the opposite side of the first member to the first conductive layer,
The liquid ejecting head according to claim 1, wherein the first member exposed at the opening is thinner than the first member not exposed at the opening. The second conductive layer has a first portion that surrounds the opening and projects from the piezoelectric layer, and a second portion that covers the piezoelectric layer,
The liquid ejecting head according to claim 1, wherein the protective film is formed to cover at least a part of the first portion. The second conductive layer has a first portion that surrounds the opening and projects from the piezoelectric layer, and a second portion that covers the piezoelectric layer,
The liquid ejecting head according to claim 1, wherein the protective film is formed to cover at least a part of the first portion and the second portion.   The liquid ejecting head according to claim 1, wherein a Young's modulus of the protective film is smaller than a Young's modulus of the second conductive layer.   The liquid ejecting head according to claim 1, wherein a Young's modulus of the protective film is 10 GPa or less.   The liquid ejecting head according to claim 1, wherein the protective film is a film having tensile stress.   The liquid ejecting head according to claim 1, wherein the protective film has conductivity.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1. A method for manufacturing a liquid jet head, comprising: a diaphragm; and a piezoelectric element formed on the first surface of the diaphragm,
The piezoelectric element includes an active portion in which a first conductive layer, a piezoelectric layer, and a second conductive layer are sequentially stacked, and an inactive state in which at least one of the piezoelectric layer and the second conductive layer is stacked. And
Forming the first conductive layer on the first surface;
Forming the piezoelectric layer;
Forming the second conductive layer;
Forming an opening exposing the first surface in the inactive portion;
Forming a protective film covering the opening with a photosensitive resin material;
A method for manufacturing a liquid jet head, comprising:   The method of manufacturing a liquid jet head according to claim 11, wherein the step of forming the opening includes a step of etching the diaphragm and thinning the diaphragm.   The method of manufacturing a liquid jet head according to claim 11, wherein in the step of forming the protective film, the protective film is formed across the active portion.

Images