JP2016036928A - Piezoelectric device, liquid ejecting head, liquid ejecting apparatus, and method of manufacturing piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezo-electric device having a piezo-electric element, a liquid spray head and a liquid spray device having a high displacement efficiency and to provide a manufacturing method of the piezo-electric device.SOLUTION: A piezo-electric device includes: a substrate 10 in which a plurality of recessed parts 12 are partitioned by barrier walls 11; a vibration plate 50 provided on one side surface side; piezo-electric elements 300 which is provided on the surface side opposite to the substrate and allows a first electrode 60, a piezo-electric material layer 70 and a second electrode 80 to be laminated from the vibration plate side. Therein, each piezo-electric element is provided on a region corresponding to a recessed part and has an active part 310 as a substantial driving part, the first electrode constitutes an individual electrode of the active part, the second electrode 80 constitutes a common electrode of a plurality of active parts, a stress applying film 200 which is extended to an upper surface of the side opposite to the piezo-electric material layer of the second electrode and allows an internal stress to become a tensile stress is provided on a region opposite to a barrier wall between the active parts adjacent to each other, and an opening part 201 is provided on a region corresponding to the center part of the upper surface of the piezoelectric element at every active part.SELECTED DRAWING: Figure 4

Description

  The present invention includes a piezoelectric device including a piezoelectric element having a first electrode, a piezoelectric layer, and a second electrode provided on a substrate via a vibration plate, a liquid ejecting head including the piezoelectric device, and a liquid ejecting head. The present invention relates to a liquid ejecting apparatus and a piezoelectric device manufacturing method.

  A liquid ejecting head that ejects liquid droplets from a nozzle opening communicating with a pressure generating chamber by deforming a piezoelectric element to cause a pressure fluctuation in the liquid in the pressure generating chamber is known. A typical example of the liquid ejecting head is an ink jet recording head that ejects ink droplets as droplets.

  An ink jet recording head includes, for example, a piezoelectric element on one side of a flow path forming substrate provided with a pressure generating chamber communicating with a nozzle opening, and deforms a diaphragm by driving the piezoelectric element, thereby The ink is caused to change in pressure, and ink droplets are ejected from the nozzle openings.

  Here, the piezoelectric element includes a first electrode, a piezoelectric layer, and a second electrode provided on the substrate. The first electrode provided on the substrate side is used as a common electrode for a plurality of active parts that serve as a substantial driving part, the second electrode is used as an individual electrode for each active part, and a protective film is provided on the piezoelectric element, thereby providing two The thing which suppressed the destruction by the leakage current between electrodes is proposed (for example, refer patent document 1 and 2).

  Also, a protective film is provided by covering the first electrode with a piezoelectric layer, with the first electrode provided on the substrate side as an individual electrode of each active part, the second electrode as a common electrode of a plurality of active parts, There is also proposed a device that suppresses breakage due to leakage current between two electrodes (see, for example, Patent Document 3).

JP 2000-141644 A JP 2000-94688 A JP 2009-196329 A

  In recent years, a so-called high displacement efficiency piezoelectric element that can obtain a large displacement with a low driving voltage is desired, but when the piezoelectric element is largely bent toward the substrate in the initial state, a voltage is applied to the piezoelectric element. If it is attempted to be deformed to the substrate side, the displacement amount of the piezoelectric element is small and the displacement efficiency is lowered.

  Such a problem is not limited to a piezoelectric element used in a liquid ejecting head such as an ink jet recording head, and similarly exists in piezoelectric elements used in other devices.

  In view of such circumstances, it is an object of the present invention to provide a piezoelectric device having a piezoelectric element with high displacement efficiency, a liquid ejecting head, a liquid ejecting apparatus, and a method for manufacturing the piezoelectric device.

An aspect of the present invention that solves the above-described problems includes a substrate in which a plurality of recesses are partitioned by a partition, a diaphragm provided on one surface side of the substrate, and a surface of the diaphragm opposite to the substrate. And a piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode laminated from the diaphragm side, wherein the piezoelectric element is provided in a region corresponding to the recess. An active part that is a substantial driving part, wherein the first electrode constitutes an individual electrode provided individually in the active part, and the second electrode is provided in common to the plurality of active parts In the region facing the partition between the active parts adjacent to each other, the common electrode is extended to the upper surface of the second electrode opposite to the piezoelectric layer, and internal stress is There is a stress-imparting film that becomes a tensile stress. In the piezoelectric device, wherein the opening in a region corresponding to the central portion of the upper surface of the piezoelectric element is provided.
In this aspect, by providing a stress applying film in which the internal stress becomes tensile stress, the piezoelectric element facing the recess is given a stress to be pulled up to the side opposite to the recess, thereby reducing the stress of the piezoelectric element being deformed to the recess side. Can be made. Therefore, the amount of deformation when the piezoelectric element is deformed to the concave side can be improved. Further, since the stress applying film is provided up to the upper surface of the piezoelectric element, the stress moment applied to the piezoelectric element can be increased, and the lifting effect of the piezoelectric element can be improved. Moreover, by providing the opening in the stress applying film, it is possible to suppress the stress applying film from inhibiting the deformation of the piezoelectric element, and to obtain a piezoelectric element having a higher displacement.

  Here, it is preferable that the stress applying film is higher in height from the diaphragm than the piezoelectric element. According to this, the stress applying film can be reliably provided up to the upper surface of the piezoelectric element, and the lifting effect of the piezoelectric element can be improved.

  Moreover, it is preferable that the internal stress of the second electrode is a compressive stress. According to this, the lifting effect of the piezoelectric element can be further improved by the second electrode.

  Moreover, it is preferable to have the compression film | membrane in which the internal stress turns into a compression stress in the said opening part of the said stress provision film | membrane. According to this, the pulling effect of the piezoelectric element can be further improved by the compression film.

  Moreover, it is preferable that a wiring having an internal stress serving as a tensile stress is provided on a surface of the stress applying film opposite to the piezoelectric element. According to this, the lifting effect of the piezoelectric element can be further improved by the wiring.

  Further, the stress applying film may be configured by laminating a plurality of layers. As a result, a relatively thick stress applying film can be easily formed.

  The stress applying film is preferably a photosensitive resin. According to this, since the stress imparting film can be exposed and developed to be formed into a predetermined shape, the influence on other films due to over-etching can be suppressed.

Furthermore, another aspect of the present invention includes the piezoelectric device according to the above aspect, wherein the concave portion is a pressure generation chamber, and has a nozzle opening communicating with the pressure generation chamber and ejecting a liquid. Located in the liquid jet head.
In this aspect, a liquid ejecting head having a piezoelectric element with improved displacement efficiency can be realized.

According to another aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head according to the above aspect.
In this aspect, a liquid ejecting apparatus having a piezoelectric element with improved displacement efficiency can be realized.

According to another aspect of the present invention, a substrate in which a plurality of recesses are partitioned by a partition, a diaphragm provided on one surface side of the substrate, and a surface of the diaphragm opposite to the substrate are provided. A piezoelectric element in which a first electrode, a piezoelectric layer, and a second electrode are laminated from the diaphragm side, and the piezoelectric element is provided in a region corresponding to the recess, The first electrode constitutes an individual electrode provided individually in the active part, and the second electrode constitutes a common electrode provided commonly in the plurality of active parts. A stress applying film extending to the upper surface on the opposite side of the piezoelectric layer of the second electrode in a region facing the partition between the active parts adjacent to each other, and the internal stress becomes a tensile stress. And an opening is provided in a region corresponding to the center of the upper surface of the piezoelectric element. In the manufacturing method of the piezoelectric device according to claim Rukoto.
In this aspect, by providing a stress applying film in which the internal stress becomes tensile stress, the piezoelectric element facing the recess is given a stress to be pulled up to the side opposite to the recess, thereby reducing the stress of the piezoelectric element being deformed to the recess side. Can be made. Therefore, the amount of deformation when the piezoelectric element is deformed to the concave side can be improved. Further, since the stress applying film is provided up to the upper surface of the piezoelectric element, the stress moment applied to the piezoelectric element can be increased, and the lifting effect of the piezoelectric element can be improved. Moreover, by providing the opening in the stress applying film, it is possible to suppress the stress applying film from inhibiting the deformation of the piezoelectric element, and to obtain a piezoelectric element having a higher displacement.

  Here, the stress applying film is preferably formed by a liquid phase method. According to this, it is possible to easily form a stress applying film whose internal stress is tensile stress.

  The second electrode is preferably formed by a vapor phase method so that the internal stress is a compressive stress. According to this, the 2nd electrode whose internal stress is compressive stress can be formed easily.

FIG. 2 is an exploded perspective view of a recording head according to Embodiment 1 of the invention. FIG. 3 is a plan view of a flow path forming substrate of the recording head according to the first embodiment of the invention. 2A and 2B are a cross-sectional view and an enlarged cross-sectional view of a recording head according to Embodiment 1 of the invention. FIG. 2 is an enlarged cross-sectional view of a main part of the recording head according to Embodiment 1 of the invention. FIG. 2 is an enlarged cross-sectional view of a main part of the recording head according to Embodiment 1 of the invention. It is sectional drawing to which the principal part of the recording head concerning the comparative example of this invention was expanded. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. FIG. 6 is an enlarged cross-sectional view of a main part of a recording head according to Embodiment 2 of the present invention. FIG. 5 is an enlarged cross-sectional view of a main part of a recording head according to Embodiment 3 of the present invention. FIG. 9 is a cross-sectional view illustrating a recording head manufacturing method according to Embodiment 3 of the invention. FIG. 9 is a cross-sectional view illustrating a recording head manufacturing method according to Embodiment 3 of the invention. FIG. 10 is a cross-sectional view illustrating a modification of the recording head according to the third embodiment of the invention. 1 is a schematic diagram illustrating a liquid ejecting apparatus according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
1 is a perspective view of an ink jet recording head that is an example of a liquid jet head according to Embodiment 1 of the present invention, and FIG. 2 is a plan view of a flow path forming substrate of the ink jet recording head. FIG. 4 is a cross-sectional view and an enlarged cross-sectional view corresponding to the line AA ′ in FIG. 2, and FIG. 4 is a cross-sectional view corresponding to the line BB ′ in FIG.

  As shown in the drawing, a pressure generating chamber 12 is formed as a recess in a flow path forming substrate 10 which is a substrate of this embodiment provided in an ink jet recording head I which is an example of a liquid jet head of this embodiment. The pressure generating chambers 12 partitioned by the plurality of partition walls 11 are arranged in parallel along the direction in which the plurality of nozzle openings 21 for discharging the same color ink are arranged in parallel. Hereinafter, this direction is referred to as a direction in which the pressure generating chambers 12 are arranged side by side or a first direction X. Further, the direction orthogonal to the first direction X is hereinafter referred to as a second direction Y. Furthermore, a direction orthogonal to both the first direction X and the second direction Y is hereinafter referred to as a third direction Z.

  An ink supply path 13 and a communication path 14 are provided on one end side in the longitudinal direction of the pressure generating chamber 12 of the flow path forming substrate 10, that is, on one end side in the second direction Y orthogonal to the first direction X. Is partitioned by a plurality of partition walls 11. On the outside of the communication passage 14 (on the side opposite to the pressure generation chamber 12 in the second direction Y), a communication portion that constitutes a part of the manifold 100 serving as a common ink chamber (liquid chamber) of each pressure generation chamber 12. 15 is formed. That is, the flow path forming substrate 10 is provided with a liquid flow path including a pressure generation chamber 12, an ink supply path 13, a communication path 14, and a communication portion 15.

  On one side of the flow path forming substrate 10, that is, the surface where the liquid flow path such as the pressure generation chamber 12 opens, a nozzle plate 20 having a nozzle opening 21 communicating with each pressure generation chamber 12 is provided with an adhesive. Or a heat-welded film or the like. In other words, the nozzle openings 21 are arranged in the nozzle plate 20 in the first direction X.

  A diaphragm 50 is formed on the other surface side of the flow path forming substrate 10. The diaphragm 50 according to the present embodiment includes an elastic film 51 formed on the flow path forming substrate 10 and an insulator film 52 formed on the elastic film 51. The liquid flow path such as the pressure generation chamber 12 is formed by anisotropically etching the flow path forming substrate 10 from one surface, and the other surface of the liquid flow path such as the pressure generation chamber 12 is a diaphragm. 50 (elastic film 51).

  On the insulator film 52, a first electrode 60 having a thickness of, for example, about 0.2 μm, a piezoelectric layer 70 having a thickness of, for example, about 1.0 μm, and a thickness of, for example, about 0.05 μm. A piezoelectric element 300 composed of the second electrode 80 is formed. In the present embodiment, the flow path forming substrate 10 in which the pressure generating chamber 12 is formed, the vibration plate 50, and the piezoelectric element 300 form an actuator device that is an example of a piezoelectric device.

  Hereinafter, the piezoelectric element 300 constituting the actuator device will be described in more detail with reference to FIGS. 5 is an enlarged cross-sectional view of the main part of the recording head according to Embodiment 1 of the present invention, and FIG. 6 is an enlarged cross-sectional view of the main part of the recording head as a comparative example.

  As shown in the drawing, 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 active unit 310 described later. The first electrode 60 is formed with a width narrower than the width of the pressure generation chamber 12 in the second direction Y of the pressure generation chamber. That is, in the first direction X of the pressure generation chamber 12, the end portion of the first electrode 60 is located inside the region facing the pressure generation chamber 12. In the second direction Y, both end portions of the first electrode 60 are extended to the outside of the pressure generation chamber 12. The material of the first electrode 60 is preferably a material that does not oxidize when the piezoelectric layer 70 described later is formed and can maintain conductivity. For example, a noble metal such as platinum (Pt) or iridium (Ir), Alternatively, a conductive oxide typified by lanthanum nickel oxide (LNO) is preferably used.

  Further, as the first electrode 60, an adhesion layer for securing an adhesion force may be used between the above-described conductive material and the diaphragm 50. In this embodiment, although not particularly shown, titanium is used as the adhesion layer. As the adhesion layer, zirconium, titanium, titanium oxide, or the like can be used. That is, in the present embodiment, the first electrode 60 is formed of an adhesion layer made of titanium and at least one type of conductive layer selected from the above-described conductive materials.

  The piezoelectric layer 70 is continuously provided in the first direction X so that the second direction Y has a predetermined width. The width of the piezoelectric layer 70 in the second direction Y is wider than the length of the pressure generation chamber 12 in the second direction Y. Therefore, in the second direction Y of the pressure generation chamber 12, the piezoelectric layer 70 is provided to the outside of the pressure generation chamber 12.

  In the second direction Y of the pressure generating chamber 12, the end of the piezoelectric layer 70 on the ink supply path side is located outside the end of the first electrode 60. That is, the end portion of the first electrode 60 is covered with the piezoelectric layer 70. The end of the piezoelectric layer 70 on the nozzle opening 21 side is located on the inner side (pressure generation chamber 12 side) of the end of the first electrode 60, and the end of the first electrode 60 on the nozzle opening 21 side. The portion is not covered with the piezoelectric layer 70.

  The piezoelectric layer 70 is a crystal film (perovskite crystal) having a perovskite structure made of a ferroelectric ceramic material having an electromechanical conversion effect and formed on the first electrode 60. 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 used. be able to. The material of the piezoelectric layer 70 is not limited to a lead-based piezoelectric material including lead, and a lead-free piezoelectric material not including lead can also be used.

  As will be described in detail later, the piezoelectric layer 70 is a liquid phase method such as a sol-gel method or a MOD (Metal-Organic Decomposition) method, or a PVD (Physical Vapor Deposition) method such as a sputtering method or a laser ablation method. Phase method).

  In the piezoelectric layer 70, a first opening 71 having a concave shape that opens to the opposite side of the flow path forming substrate 10 is formed corresponding to each partition wall 11. The first opening 71 is provided so as to penetrate the piezoelectric layer 70 in the third direction Z that is the thickness direction. The width of the first opening 71 in the first direction X is wider than the width of each partition 11 in the first direction. As a result, the rigidity of the portion (the so-called arm portion of the diaphragm 50) facing the end portion of the pressure generation chamber 12 of the diaphragm 50 in the first direction X is suppressed, and thus the piezoelectric element 300 can be displaced favorably. it can. That is, basically, the piezoelectric layer 70 is not formed on each partition wall 11. Incidentally, the piezoelectric layer 70 may be formed on the partition wall 11 at the end of the partition wall 11 in the second direction Y. That is, the length of the first opening 71 in the second direction Y is longer than the pressure generation chamber 12 and may extend to the outside of the end portion of the pressure generation chamber 12. It may be short and provided inside the end of the pressure generation chamber 12.

  The second electrode 80 is provided on the opposite surface side of the piezoelectric layer 70 from the first electrode 60 and constitutes a common electrode common to the plurality of active portions 310. In the present embodiment, the second electrode 80 includes a first layer 81 provided on the piezoelectric layer 70 side and a second layer 82 provided on the opposite side of the first layer 81 from the piezoelectric layer 70. It has.

  The first layer 81 is preferably made of a material that can satisfactorily form an interface with the piezoelectric layer 70, and that can exhibit insulating properties and piezoelectric characteristics. A conductive oxide represented by noble metal materials such as lanthanum nickel oxide (LNO) is preferably used. The first layer 81 may be a stacked layer of a plurality of materials. In this embodiment, a laminated electrode of iridium (Ir) and titanium (Ti) (iridium is in contact with the piezoelectric layer 70) is used. The first layer 81 is formed by a liquid phase method such as a PVD (Physical Vapor Deposition) method (vapor phase method) such as a sputtering method or a laser ablation method, a sol-gel method, a MOD (Metal-Organic Decomposition) method, or a plating method. Can be formed. In addition, the characteristics of the piezoelectric layer 70 can be improved by performing a heat treatment after the formation of the first layer 81. Such a first layer 81 is formed only on the piezoelectric layer 70, that is, only on the surface of the piezoelectric layer 70 opposite to the flow path forming substrate 10.

  The second layer 82 constituting the second electrode 80 is made of a conductive material such as iridium (Ir), platinum (Pt), palladium (Pd), or gold (Au). it can. Of course, the second layer 82 may be a single material of the metal material or a plurality of materials in which a plurality of materials are mixed. Further, titanium or the like may be provided between the first layer 81 and the second layer 82. In the present embodiment, a laminated electrode of iridium (Ir) and titanium (Ti) is used as the second layer 82.

  In the present embodiment, such a second layer 82 is continuous over the first layer 81, the side surface of the piezoelectric layer 70 where the first layer 81 is not provided, and the first electrode 60. Is provided. That is, the second layer 82 includes the side surface exposed by the first opening 71 of the piezoelectric layer 70, the diaphragm 50 that is the bottom surface of the first opening 71, that is, the inner surface of the first opening 71. Are provided. The second layer 82 is formed thicker than the first layer 81 in order to reduce the electrical resistance. And since internal stress (residual stress) is compressive stress in iridium, and internal stress is substantially 0 (zero) in titanium, the second electrode 80 of this embodiment has internal stress as compressive stress. It has become. Of course, the internal stress (residual stress) of the second electrode 80 may be set as a tensile stress by changing the material or manufacturing method of the second electrode 80, but the second electrode 80 is compressed as described in detail later. By using the stress, the displacement amount of the active part 310 can be improved. In other words, the internal stress of the second electrode 80 is a compressive stress. When a plurality of layers of the second electrode 80 are stacked, even if some of the layers are tensile stress, It only has to be. Incidentally, the second layer 82 on the first layer 81 and the second layer 82 on the first electrode 60 are electrically disconnected via the removing unit 83. That is, the second layer 82 on the first layer 81 and the second layer 82 on the first electrode 60 are formed of the same layer but are electrically discontinuous. Here, the removing portion 83 is provided on the nozzle opening 21 side on the piezoelectric layer 70, and the second electrode 80, that is, the first layer 81 and the second layer 82 are arranged in the thickness direction (first layer 81). And the second layer 82 in the stacking direction) and electrically cut. Such a removal portion 83 is provided so as to penetrate the second electrode 80 in the thickness direction continuously in the first direction X.

  Such a piezoelectric element 300 including the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is displaced by applying a voltage between the first electrode 60 and the second electrode 80. That is, by applying a voltage between both electrodes, a piezoelectric strain is generated in the piezoelectric layer 70 sandwiched between the first electrode 60 and the second electrode 80. A portion where piezoelectric distortion occurs in the piezoelectric layer 70 when a voltage is applied to both electrodes is referred to as an active portion 310. On the other hand, a portion where no piezoelectric distortion occurs in the piezoelectric layer 70 is referred to as an inactive portion. Further, in the active part 310 in which piezoelectric distortion occurs in the piezoelectric layer 70, a part facing the pressure generation chamber 12 is referred to as a flexible part, and a part outside the pressure generation chamber 12 is referred to as a non-flexible part.

  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 in the second direction Y. That is, the active part 310 is continuously provided to the outside of the pressure generation chamber 12. Therefore, a portion of the active portion 310 that faces the pressure generation chamber 12 of the piezoelectric element 300 is a flexible portion, and a portion outside the pressure generation chamber 12 is a non-flexible portion.

  That is, in the present embodiment, as shown in FIG. 3, the end of the active part 310 in the second direction Y is defined by the second electrode 80 (removal part 83).

  Further, the end of the active part 310 in the first direction X is defined by the first electrode 60. The end portion of the first electrode 60 in the first direction X is provided in a region facing the pressure generation chamber 12. Therefore, the end portion of the active portion 310 in the first direction X is provided in the flexible portion, and in the first direction X, the stress at the boundary between the active portion 310 and the inactive portion is caused by the diaphragm. It is released by deformation. For this reason, destruction such as burnout and cracks due to stress concentration at the end portion of the active portion 310 in the first direction X can be suppressed.

  In such a piezoelectric element 300, since the second electrode 80 covers the piezoelectric layer 70, current does not leak between the first electrode 60 and the second electrode 80, and the piezoelectric element 300 is destroyed. Can be suppressed. Incidentally, if the first electrode 60 and the second electrode 80 are exposed in the proximity of each other, current leaks from the surface of the piezoelectric layer 70 and the piezoelectric layer 70 is destroyed. Further, even if the first electrode 60 and the second electrode 80 are exposed, current leakage does not occur unless the distance is short.

  Further, as shown in FIG. 4, a stress applying film 200 is provided on the diaphragm 50 in the first opening 71 of such an actuator device.

  The stress applying film 200 is provided in the first opening 71 as an inner surface of the first opening 71 in the second direction Y, that is, as an inner surface of the first opening 71 of the piezoelectric element 300 in the second direction Y. It is provided in contact with the exposed second layer 82. The stress applying film 200 extends to the upper surface of the piezoelectric element 300, that is, the surface opposite to the flow path forming substrate 10 in the third direction Z, and the center of the second electrode 80 of the active portion 310. A second opening 201 is provided in a region corresponding to the portion. That is, the second opening 201 is provided in a region corresponding to the central portion of the upper surface of the piezoelectric element 300 for each active portion 310, and in the present embodiment, the second electrode 80 is exposed by the second opening 201. ing.

  Such stress applying films 200 are provided on both sides of each active portion 310 in the first direction X, and a first opening between two active portions 310 adjacent to each other in the first direction X is provided. The unit 71 is provided continuously. Of course, the stress applying film 200 is not limited to this, and the stress applying film 200 is provided on both sides of each active part 310 in the first direction X and provided between the active parts 310 adjacent to each other in the first direction X. The film 200 may be provided independently without being continuous on the partition wall 11. Further, the stress applying films 200 provided on both sides in the first direction X of each active part 310 are provided on the outside of the active part 310 in the second direction Y, or may be provided separately. It may be. This is because the piezoelectric elements 300 on both sides of the first opening 71 in the second direction Y do not contribute to the deformation of the active portion 310.

  As such a stress imparting film 200, internal stress (residual stress) has tensile stress, and imparts tensile stress to the piezoelectric element 300. The stress applying film 200 may be an insulating material or a conductive material, and may be an inorganic material or an organic material. In addition, since the stress applying film 200 is provided in a region that covers the side surface of the piezoelectric element 300 and faces the pressure generation chamber 12 of the diaphragm 50, it is preferable to use a material having a relatively low Young's modulus. As a result, it is possible to suppress the stress applying film 200 from inhibiting the deformation of the piezoelectric element 300 and the diaphragm 50 and reducing the amount of displacement. As described above, it is preferable to use an organic material as a material having a low Young's modulus. The stress applying film 200 is preferably made of a material that does not affect other layers, for example, the vibration plate 50 and the second electrode 80 when the stress applying film 200 is formed and patterned. A photosensitive resin such as polyimide can be preferably used. As described above, by using a photosensitive resin as the stress applying film 200, it is not necessary to perform patterning using dry etching or the like, and a part of the diaphragm 50, the piezoelectric element 300, or the like is removed by overetching by dry etching. Can be suppressed. The stress applying film 200 may be configured by stacking a plurality of layers. Thereby, a relatively thick stress applying film 200 can be easily formed. Incidentally, even if the internal stress of a part of the layers constituting the stress imparting film 200 is a compressive stress, it may be a tensile stress as a whole.

  Furthermore, the stress applying film 200 is preferably higher than the height in the third direction Z from the diaphragm 50 of the piezoelectric element 300. That is, the thickness in the third direction Z of the stress applying film 200 is preferably formed to be thicker than the thickness in the third direction Z of the piezoelectric element 300. Thereby, the stress applying film 200 can be reliably provided up to the upper surface of the piezoelectric element 300, that is, the surface opposite to the flow path forming substrate 10 in the third direction Z. In addition, the lifting effect of the piezoelectric element 300 can be improved. In the present embodiment, the stress applying film 200 is made thicker than the thickness of the piezoelectric element 300 in the third direction Z by using photosensitive polyimide as the stress applying film 200.

  By providing the stress applying film 200 in this manner, a stress is applied to pull up the piezoelectric element 300 in the third direction Z toward the side opposite to the pressure generating chamber 12. That is, as illustrated in FIG. 5, the diaphragm 50 and the active portion 310 of the piezoelectric element 300 reduce the amount of protrusion of the flow path forming substrate 10 into the pressure generation chamber 12 in a state where no electric field is applied. . In particular, in the present embodiment, since the stress applying film 200 is provided up to the upper surface of the piezoelectric element 300, the stress moment for pulling the piezoelectric element 300 in the first direction X and pulling up in the third direction Z on the upper surface. The pulling effect of the piezoelectric element 300 can be improved. That is, if the stress applying film 200 is provided only to contact the side surface without extending to the upper surface of the piezoelectric element 300, the pulling effect of the piezoelectric element 300 is reduced.

  On the other hand, as shown in FIG. 6, when the stress applying film 200 is not provided, the piezoelectric element 300 faces the inside of the pressure generating chamber 12 of the flow path forming substrate 10 in a state where no electric field is applied. It will be deformed so as to be largely convex.

  For this reason, when an electric field is applied to the piezoelectric element 300 and displaced so as to be convex in the pressure generating chamber 12, the displacement d2 of the piezoelectric element 300 when the stress applying film 200 shown in FIG. As shown in FIG. 5, the piezoelectric element 300 provided with the stress applying film 200 can obtain a larger displacement d1 (d1> d2). That is, when the stress applying film 200 is provided, it is possible to obtain a piezoelectric element 300 that can obtain a large amount of displacement at a low voltage and has a high displacement efficiency. In the present embodiment, by providing the stress applying film 200, the amount of protrusion deformed into a convex shape in the pressure generating chamber 12 can be reduced. However, the diaphragm 50, the piezoelectric element 300, and the stress applying film 200 Depending on the film thickness, material, and the like, by providing the stress applying film 200, the piezoelectric element 300 may be deformed so as to protrude to the opposite side to the pressure generating chamber 12 in the state where no electric field is applied.

  In the present embodiment, the stress applying film 200 is provided with the second opening 201 that exposes the upper surface of the piezoelectric element 300, that is, the main part of the second electrode 80. For this reason, compared with the case where the 2nd opening part 201 is not provided in the stress provision film | membrane 200, the stress provision film | membrane 200 can suppress that the displacement amount of the piezoelectric element 300 falls. That is, the stress applying film 200 can be applied to the piezoelectric element 300 by providing the stress applying film 200 continuously on the second electrode 80 without providing the second opening 201, If the second opening 201 is not provided, deformation of the piezoelectric element 300 is hindered by the stress applying film 200 and the pulling effect due to internal stress of the stress applying film 200 is also reduced.

  In the present embodiment, in addition to providing the stress applying film 200, the second electrode 80 whose internal stress is a compressive stress is provided, so that the stress that pulls the active portion 310 to the side opposite to the pressure generation chamber 12 is increased. The piezoelectric element 300 having higher displacement efficiency can be provided.

  As shown in FIGS. 3 and 4, the first electrode 60 and the second electrode 80 of the piezoelectric element 300 have an individual lead electrode 91 that is a wiring layer of the present embodiment, and a common lead electrode 92 ( (See FIG. 2).

  In this embodiment, the individual lead electrode 91 and the common lead electrode 92 (hereinafter collectively referred to as the lead electrode 90) are made of the same layer but are electrically discontinuous. Specifically, the lead electrode 90 includes an adhesion layer 191 provided on the electrode (second layer 82 of the second electrode 80) side and a conductive layer 192 provided on the adhesion layer 191.

  The adhesion layer 191 is for improving the adhesion between the second layer 82, the diaphragm 50 and the conductive layer 192. Examples of the material include nickel (Ni), chromium (Cr), and nickel chromium. (NiCr), titanium (Ti), titanium tungsten (TiW), or the like can be used. Of course, the adhesion layer 191 may be one using the above-described material as a single material, or may be a plurality of materials in which a plurality of materials are mixed, and further, a plurality of layers of different materials are laminated. It may be a thing. In the present embodiment, nickel chrome (NiCr) is used as the adhesion layer 191.

  The conductive layer 192 is not particularly limited as long as it is a material having relatively high conductivity. For example, gold (Au), platinum (Pt), aluminum (Al), copper (Cu), or the like can be used. In this embodiment, gold (Au) is used as the conductive layer 192.

  Here, the individual lead electrode 91 is provided on the first electrode 60 provided outside the piezoelectric layer 70. Incidentally, on the first electrode 60, as described above, an electrode layer which is the same layer as the second layer 82 of the second electrode 80 but is discontinuous with the second layer 82 is provided. Therefore, the first electrode 60 and the individual lead electrode 91 are electrically connected to each other through the electrode layer that is the same layer as the second layer 82 and is discontinuous with the second layer 82.

  The common lead electrode 92 is provided on the second electrode 80 (on the second electrode 80 of the piezoelectric layer 70). As shown in FIGS. 1 and 2, the common lead electrode 92 is drawn out on the diaphragm 50 continuously in the second direction Y at both ends in the first direction X of the flow path forming substrate 10. It is.

  Further, the common lead electrode 92 has an extending portion 93 provided on the wall surface of the pressure generating chamber 12 in the second direction Y, that is, across the boundary portion between the flexible portion and the non-flexible portion. . The extending portion 93 is provided continuously in the first direction X of the plurality of active portions 310, and continues to the common lead electrode 92 at both end portions in the first direction X. That is, the common lead electrode 92 having the extending portion 93 is continuously disposed so as to surround the active portion 310 when viewed in plan from the protective substrate 30 side. In this manner, by providing the extending portion 93, it is possible to suppress the breakage of the piezoelectric layer 70 due to stress concentration at the boundary between the flexible portion and the non-flexible portion. Further, since the common lead electrode 92 is not substantially formed on the flexible portion, it is possible to suppress a decrease in displacement of the active portion 310.

  On the flow path forming substrate 10 on which such a piezoelectric element 300 is formed, as shown in FIG. 3, a protective substrate 30 that protects the piezoelectric element 300 is bonded by an adhesive 35. The protective substrate 30 is provided with a piezoelectric element holding portion 31 that is a recess that defines a space for accommodating the piezoelectric element 300. The protective substrate 30 is provided with a manifold portion 32 that constitutes a part of the manifold 100. The manifold portion 32 penetrates the protective substrate 30 in the thickness direction and is formed across the width direction of the pressure generating chamber 12 and communicates with the communication portion 15 of the flow path forming substrate 10 as described above. The protective substrate 30 is provided with a through hole 33 that penetrates the protective substrate 30 in the thickness direction. The lead electrode 90 connected to the first electrode 60 of each active part 310 is exposed in the through hole 33, and one end of a connection wiring connected to a drive circuit (not shown) is lead in the through hole 33. It is connected to the electrode 90.

  On the protective substrate 30, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded. The sealing film 41 is made of a material having low rigidity and flexibility, and one surface of the manifold portion 32 is sealed by the sealing film 41. The fixing plate 42 is made of a hard material such as metal. Since the area of the fixing plate 42 facing the manifold 100 is an opening 43 that is completely removed in the thickness direction, one surface of the manifold 100 is sealed only with a flexible sealing film 41. Has been.

  In such an ink jet recording head I of this embodiment, after taking ink from an ink introduction port connected to an external ink supply means (not shown) and filling the interior from the manifold 100 to the nozzle opening 21, the drive circuit A voltage is applied between each of the first electrode 60 and the second electrode 80 corresponding to the pressure generating chamber 12 in accordance with the recording signal from. 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.

  Here, a method for manufacturing the ink jet recording head of the present embodiment will be described. 7 to 12 are cross-sectional views showing a method for manufacturing an ink jet recording head.

  First, as shown in FIG. 7A, the diaphragm 50 is formed on the surface of a flow path forming substrate wafer 110, which is a silicon wafer on which a plurality of flow path forming substrates 10 are integrally formed. In this embodiment, silicon dioxide (elastic film 51) formed by thermally oxidizing the flow path forming substrate wafer 110 and zirconium oxide (insulator film 52) formed by thermal oxidation after film formation by sputtering. ) Was formed.

  Next, as shown in FIG. 7B, a first electrode 60 is formed on the entire surface of the insulator film 52. The material of the first electrode 60 is not particularly limited. For example, metals such as platinum and iridium that do not lose their conductivity even at high-temperature oxidation treatment, conductive oxides such as iridium oxide and lanthanum nickel oxide, and these A laminated material is preferably used. The first electrode 60 can be formed by, for example, vapor phase film formation such as sputtering, PVD (physical vapor deposition), or laser ablation, or liquid phase film formation such as spin coating. Further, an adhesion layer for ensuring adhesion can be used between the conductive material described above and the diaphragm 50. In this embodiment, although not particularly shown, titanium is used as the adhesion layer. As the adhesion layer, zirconium, titanium, titanium oxide, or the like can be used. In addition, a control layer for controlling crystal growth of the piezoelectric layer 70 may be formed on the electrode surface (film formation side of the piezoelectric layer 70). In this embodiment, titanium is used for crystal control of the piezoelectric layer 70 (PZT). Since titanium is taken into the piezoelectric layer 70 when the piezoelectric layer 70 is formed, it does not exist as a film after the piezoelectric layer 70 is formed. As the crystal control layer, a conductive oxide having a perovskite crystal structure such as lanthanum nickel oxide may be used.

  Next, in this embodiment, the piezoelectric layer 70 made of lead zirconate titanate (PZT) is formed. Here, in this embodiment, a so-called sol-gel in which a so-called sol in which a metal complex is dissolved / dispersed 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 method for manufacturing the piezoelectric layer 70 is not limited to the sol-gel method, and for example, using a MOD (Metal-Organic Decomposition) method, a PVD (Physical Vapor Deposition) method such as a sputtering method or a laser ablation method. Also good. That is, the piezoelectric layer 70 may be formed by either a liquid phase method or a gas phase method. In the present embodiment, the piezoelectric layer 70 is formed by laminating a plurality of piezoelectric films 74.

  Specifically, as shown in FIG. 8A, when the first piezoelectric film 74 is formed on the first electrode 60, the first electrode 60 and the first piezoelectric film 74 are formed on the first electrode 60 and the first piezoelectric film 74, respectively. At the same time, patterning is performed so that the side surfaces of the film are inclined. The patterning of the first electrode 60 and the first piezoelectric film 74 can be performed by dry etching such as reactive ion etching (RIE) or ion milling, for example.

  Here, for example, when the first piezoelectric film 74 is formed after patterning the first electrode 60, the first electrode 60 is patterned because the first electrode 60 is patterned by a photo process, ion milling, and ashing. The surface and a crystal seed layer such as titanium (not shown) provided on the surface are denatured. Then, even if the piezoelectric film 74 is formed on the altered surface, the crystallinity of the piezoelectric film 74 is not good, and the second and subsequent piezoelectric films 74 are also crystals of the first piezoelectric film 74. Since the crystal growth is influenced by the state, the piezoelectric layer 70 having good crystallinity cannot be formed.

  In contrast, if the first piezoelectric film 74 is formed and then patterned at the same time as the first electrode 60, the first piezoelectric film 74 is the second and subsequent piezoelectric films compared to the crystal species such as titanium. The seed 74 has a strong property as a seed (crystal seed) for satisfactorily growing a crystal, and even if an extremely thin altered layer is formed on the surface layer by patterning, the crystal growth of the second and subsequent piezoelectric films 74 is not greatly affected. .

  The second and subsequent piezoelectric films 74 are formed on the diaphragm 50 (in this embodiment, the insulator film 52 made of zirconium oxide) exposed before the second piezoelectric film 74 is formed. When forming the film, a crystal control layer (intermediate crystal control layer) may be used. In this embodiment, titanium is used as the intermediate crystal control layer. The intermediate crystal control layer made of titanium is taken into the piezoelectric film 74 when the piezoelectric film 74 is formed, similarly to the titanium of the crystal control layer formed on the first electrode 60. Incidentally, if the intermediate crystal control layer becomes a dielectric of an intermediate electrode or a capacitor connected in series, it causes a decrease in piezoelectric characteristics. Therefore, it is desirable that the intermediate crystal control layer is taken into the piezoelectric film 74 (piezoelectric layer 70) and does not remain as a film after the piezoelectric layer 70 is formed.

  Next, as shown in FIG. 8B, a piezoelectric layer 70 composed of a plurality of layers of piezoelectric films 74 is formed by laminating the second and subsequent layers of piezoelectric films 74.

  Incidentally, the second and subsequent piezoelectric films 74 are continuous over the insulator film 52, on the side surfaces of the first electrode 60 and the first piezoelectric film 74, and on the first piezoelectric film 74. Formed.

  Next, as shown in FIG. 8C, the first layer 81 constituting the second electrode 80 is formed on the piezoelectric layer 70. Although not particularly shown in the present embodiment, first, an iridium layer having iridium on the piezoelectric layer 70 and a titanium layer having titanium on the iridium layer are laminated. Note that the iridium layer and the titanium layer can be formed by a sputtering method, a CVD method, or the like. Thereafter, the piezoelectric layer 70 on which the iridium layer and the titanium layer are formed is further reheated (post-annealed). By performing the reheating treatment in this way, even if damage is caused when an iridium layer or the like is formed on the second electrode 80 side of the piezoelectric layer 70, the reheating treatment can be performed to damage the piezoelectric layer 70. Thus, the piezoelectric characteristics of the piezoelectric layer 70 can be improved. Moreover, the post-annealing can improve the piezoelectric characteristics of the piezoelectric layer 70 and make the piezoelectric characteristics uniform.

  Next, as shown in FIG. 9A, the first layer 81 and the piezoelectric layer 70 are patterned corresponding to each pressure generating chamber 12. In the present embodiment, a mask (not shown) formed in a predetermined shape is provided on the first layer 81, and the first layer 81 and the piezoelectric layer 70 are etched through the mask, and patterning is performed by so-called photolithography. Examples of the patterning of the piezoelectric layer 70 include dry etching such as reactive ion etching and ion milling. As a result, the piezoelectric layer 70 is patterned to form the first opening 71 (see FIG. 2) and the like.

  Next, as shown in FIG. 9B, over one surface side of the flow path forming substrate wafer 110 (the surface side on which the piezoelectric layer 70 is formed), that is, on the first layer 81, the piezoelectric material The second electrode 80 is formed by forming the second layer 82 over the side surface on which the layer 70 is patterned, the insulator film 52, the first electrode 60, and the like.

  Next, as shown in FIG. 9C, the second electrode 80 is patterned into a predetermined shape. Thereby, the removal portion 83 and the like are formed.

  Next, the stress applying film 200 is formed. First, as shown in FIG. 10A, the stress applying film 200 is formed over one surface of the flow path forming substrate wafer 110. The material of the stress imparting film 200 is not particularly limited as long as the internal stress becomes a tensile stress, and an inorganic material or an organic material can be used. The stress applying film 200 of an inorganic material can be formed by vapor phase film formation such as MOD method, sol-gel method, sputtering method, and CVD method, for example. Further, the stress applying film 200 made of an organic material can be formed by liquid phase film formation which is a solution coating method such as a spin coating method, a spray method, or a slit coating method. In this embodiment, as the stress applying film 200, photosensitive polyimide is formed thicker than the piezoelectric element 300 by spin coating.

  Next, as shown in FIG. 10B, the stress applying film 200 is patterned into a predetermined shape to form second openings 201 and the like. In this embodiment, the stress-imparting film 200 having a predetermined shape is formed by exposing and developing photosensitive polyimide. Thus, by using a photosensitive resin as the stress applying film 200, the stress applying film 200 is patterned without using dry etching or the like, so that the diaphragm 50, the second electrode 80, the piezoelectric layer 70, and the like are dry etched. It is possible to suppress removal of a part by over-etching due to.

  When an insulating film is used for the stress applying film 200, the stress applying film 200 may be formed also on the removal portion 83. In this case, the stress applying film 200 can be a protective film that protects the piezoelectric layer 70 exposed at the removing portion 83.

  Next, as shown in FIG. 11A, the lead electrode 90 is formed over the entire one surface of the flow path forming substrate wafer 110. In the present embodiment, the lead electrode 90 is formed by laminating the adhesion layer 191 and the conductive layer 192.

  Next, as shown in FIG. 11B, the lead electrode 90 is patterned into a predetermined shape. In patterning the lead electrode 90, after the conductive layer 192 is first patterned by wet etching or the like, the adhesion layer 191 may be patterned by wet etching.

  Next, as shown in FIG. 12A, a protective substrate wafer 130 that is a silicon wafer and serves as a plurality of protective substrates 30 is placed on the piezoelectric element 300 side of the flow path forming substrate wafer 110 via an adhesive 35. After bonding, the flow path forming substrate wafer 110 is thinned to a predetermined thickness.

  Next, as shown in FIG. 12B, a mask film 53 is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, as shown in FIG. 12C, the flow path forming substrate wafer 110 is anisotropically etched (wet etching) using an alkaline solution such as KOH through the mask film 53, thereby forming the piezoelectric element 300. Corresponding pressure generating chambers 12, ink supply passages 13, communication passages 14, communication portions 15 and the like are formed. Thereby, the restriction of the flow path forming substrate wafer 110 (the vibration plate 50) is released, and the piezoelectric element 300 is deformed as shown in FIG. 6 due to the influence of internal stress.

  Thereafter, unnecessary portions of the outer peripheral edge portions of the flow path forming substrate wafer 110 and the protective substrate wafer 130 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 40 is bonded to the protective substrate wafer 130. By dividing the flow path forming substrate wafer 110 and the like into a single chip size flow path forming substrate 10 and the like as shown in FIG. 1, the ink jet recording head of this embodiment is obtained.

(Embodiment 2)
FIG. 13 is an enlarged cross-sectional view of a main part of an ink jet recording head which is an example of a liquid jet head according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member similar to Embodiment 1 mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in the figure, the stress applying film 200 having the second opening 201 is provided in the piezoelectric element 300 as in the first embodiment.

  The second opening 201 is provided with a compression film 210 whose internal stress is a compressive stress. The compressed film 210 extends from the second electrode 80 exposed in the second opening 201 to the opening edge of the second opening 201 of the stress applying film 200. By providing the compression film 210 on the second electrode 80 in this manner, it is possible to apply a stress that raises the piezoelectric element 300 further to the side opposite to the pressure generation chamber 12 and improve the lifting effect.

  Such a compression film 210 may be formed by forming and patterning the stress applying film 200 and forming the second opening 201 and then patterning it.

(Embodiment 3)
FIG. 14 is an enlarged cross-sectional view of a main part of an ink jet recording head which is an example of a liquid jet head according to Embodiment 3 of the present invention. In addition, the same code | symbol is attached | subjected to the member similar to embodiment mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 14, the piezoelectric element 300 provided on the flow path forming substrate 10 via the vibration plate 50 includes a first electrode 60, a piezoelectric layer 70, and a second electrode 80.

  The second electrode 80 includes a first layer 81 and a second layer 82A that is a wiring provided on the first layer 81. The piezoelectric element 300 is provided with a stress applying film 200. The second layer 82A of the second electrode 80 is provided on the stress applying film 200 in the present embodiment. That is, the second electrode 80 is configured by the first layer 81 provided on the upper surface of the piezoelectric layer 70 and the second layer 82A provided on the stress applying film 200. The second layer 82A extends to the first layer 81 in the second opening 201 of the stress applying film 200, and is electrically connected to the first layer 81 in the second opening 201. ing. The second layer 82 </ b> A has a third opening 84 in a region corresponding to the center of the first layer 81 in the second opening 201. That is, the second layer 82 exposes the central portion of the upper surface of the first layer 81 through the third opening 84.

  Such a second layer 82 has a tensile stress as an internal stress. The second layer 82 whose internal stress becomes tensile stress can be formed by a liquid phase method such as a plating method or a spin coating method. Of course, the second layer 82A may be formed by stacking a plurality of layers. The second layer 82A may be a tensile stress as a whole even if the internal stress of some of the stacked layers is a compressive stress. In the present embodiment, the second layer 82A is formed by laminating two layers of a catalyst layer 85 and a plating layer 86 by a manufacturing method described in detail later.

  Thus, by providing the second layer 82A in which the internal stress becomes tensile stress on the stress applying film 200, the lifting effect of the piezoelectric element 300 can be improved by the second layer 82A, and the displacement characteristics can be improved. That is, the second layer 82A is provided on the stress applying film 200 as compared with the case where the second layer 82 is provided along the side surface of the piezoelectric layer 70 as in the first embodiment described above. The stress moment for pulling up the piezoelectric element 300 by the layer 82A can be improved, and the pulling effect of the piezoelectric element 300 can be improved. Further, by providing the second layer 82A as the second electrode 80 without providing only the first layer 81, the electrical resistance value of the second electrode 80 can be reduced, and electric crosstalk can be suppressed.

  In the present embodiment, the second layer 82A is provided on the stress applying film 200 in place of the second layer 82 in the first embodiment described above. However, the present invention is not particularly limited thereto. Both the first second layer 82 and the second layer 82A of the present embodiment may be provided. Thereby, the pulling effect of the piezoelectric element 300 can be further improved, and the electric resistance value of the second electrode 80 can be further reduced to further suppress the electric crosstalk.

  Here, the manufacturing method of the ink jet recording head of this embodiment will be described with reference to FIGS. In addition, description is abbreviate | omitted about the process which overlaps with Embodiment 1 mentioned above.

  As shown in FIG. 15A, the diaphragm 50, the first electrode 60, the piezoelectric layer 70, and the first layer 81 are formed in a predetermined shape on one surface of the flow path forming substrate wafer 110 as in the first embodiment. Then, the stress applying film 200 having the second opening 201 is formed. The manufacturing method of each film is the same as that of the first embodiment.

  Next, as shown in FIG. 15B, a resist 220 is formed over the stress applying film 200 and the first layer 81 and only the central portion of the first layer 81, that is, the third opening 84 is formed. Patterning is performed so that the resist 220 remains only in the region to be formed.

  Next, as shown in FIG. 15C, a catalyst layer 85 is formed on the stress applying film 200, the first layer 81, and the resist 220. The catalyst layer 85 functions as a catalyst (activator) for later electroless plating, and contains palladium (Pd) as a main component. As a method of forming the catalyst layer 85, there are generally a dip type and a spray type (spin type), and the dip type is a method of immersing an object in a chemical bath. As a dip type, for example, after immersing an object in a sensitizer solution which is a hydrochloric acid solution of tin chloride, and then immersing it in an activator solution consisting of a hydrochloric acid solution of palladium chloride, a method of applying a catalyst made of palladium ( Sensitizer-activator method). Incidentally, the spray method is a method of spraying a chemical solution from a nozzle onto an object. In addition, there is an ink jet method in which a chemical solution is ejected onto an object using an ink jet recording head. In the present embodiment, the catalyst layer 85 is formed by a dip method. By forming the catalyst layer 85 by the dip method in this way, batch (collective) processing can be performed, so that the efficiency of the production process can be improved.

  Next, as shown in FIG. 16A, the resist 220 is removed (lift-off). Thereby, only the catalyst layer 85 formed on the resist 220 is removed simultaneously.

  Next, as shown in FIG. 16B, a plating layer 86 is formed on the catalyst layer 85 by electroless plating. In the present embodiment, the plating layer 86 includes nickel (Ni) as a main component. Thus, by forming the plating layer 86 by electroless plating, the plating layer 86 can be selectively formed only in the region where the catalyst layer 85 is formed as a catalyst. Thereby, the second layer 82A in which the catalyst layer 85 having the third opening 84 and the plating layer 86 are laminated is formed. Further, by forming the plating layer 86 by electroless plating, the internal stress of the plating layer 86 can be used as tensile stress, and the internal stress of the entire second layer 82 can be used as tensile stress.

  Thereafter, similarly to the first embodiment described above, the second electrode 80 is patterned into a predetermined shape to form the piezoelectric element 300, and then the lead electrode 90 is formed. Then, the protective substrate wafer 130 is bonded to the flow path forming substrate wafer 110 to form a flow path such as the pressure generating chamber 12 in the flow path forming substrate wafer 110. Thereafter, the nozzle plate 20, the compliance substrate 40, and the like are joined, and the flow path forming substrate wafer 110 and the protective substrate wafer 130 are divided to obtain the ink jet recording head I of this embodiment.

  In the present embodiment, the second layer 82A has a laminated structure of the catalyst layer 85 and the plating layer 86. However, the second layer 82A is not particularly limited to this, and is formed on the plating layer 86 by a catalyst layer or electroless plating. A plated layer of gold or the like may be provided. The second layer 82A may be a single layer as long as the internal stress is a tensile stress, or may be formed by a method other than electroless plating.

  Further, the compression film 210 of the second embodiment may be further provided on the piezoelectric element 300 of the present embodiment. Such an example is shown in FIG. FIG. 17 is a cross-sectional view showing a modification of the recording head according to Embodiment 3 of the invention.

  As shown in FIG. 17, a compression film 210 having an internal stress of compressive stress is provided in the third opening 84 of the second layer 82A. In the third direction Z, the compression film 210 extends to a region facing the opening edge of the second opening 201 of the stress applying film 200. Thus, by further providing the compression film 210 on the piezoelectric element 300 of the present embodiment, the effect of pulling the piezoelectric element 300 to the side opposite to the pressure generating chamber 12 is further improved, and the displacement characteristics of the piezoelectric element 300 are improved. be able to.

(Other embodiments)
As mentioned above, although each embodiment of this invention was described, the fundamental structure of this invention is not limited to what was mentioned above.

  For example, in the first to third embodiments described above, the configuration in which the piezoelectric layer 70 of each active part 310 is continuously provided has been illustrated, but of course, the piezoelectric layer 70 is provided independently for each active part 310. It may be done. That is, the first opening 71 may be provided in the second direction Y, and the piezoelectric layer 70 may be completely cut for each active part 310.

  In Embodiment 1 described above, the second electrode 80 is formed by laminating the first layer 81 and the second layer 82. However, the present invention is not particularly limited to this, and the second electrode 80 may be a single layer. It may be a laminate of three or more layers. That is, in the first embodiment, the second electrode 80 may be configured by only the first layer 81.

  Moreover, although Embodiment 1-3 mentioned above illustrated the structure by which the pressure generation chamber 12 which is a recessed part was penetrated and provided in the 3rd direction Z which is a thickness direction in the flow-path formation board | substrate 10 which is a board | substrate. For example, the pressure generation chamber 12 may not be provided so as to penetrate the flow path forming substrate 10 in the third direction Z. That is, the pressure generation chamber 12 may be provided to be opened on the diaphragm 50 side, and the pressure generation chamber 12 and the nozzle opening 21 may communicate with each other via a nozzle communication path or the like. Further, the pressure generation chamber 12 is provided so as to open to the nozzle opening 21 side, and a part of the flow path forming substrate 10 on the piezoelectric element 300 side is left and the remaining part is used as a part of the diaphragm. Good. That is, the concave portion includes one that penetrates the substrate such as the flow path forming substrate 10 in the thickness direction and one that opens only on one of the surfaces.

  The ink jet recording head I is mounted on an ink jet recording apparatus II, for example, as shown in FIG.

  As shown in FIG. 18, the recording head units 1A and 1B having the ink jet recording head I are detachably provided with cartridges 2A and 2B constituting ink supply means, and a carriage on which the recording head units 1A and 1B are mounted. 3 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 units 1A and 1B eject, for example, a black ink composition and a color ink composition.

  Then, 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 units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus main body 4 is provided with a conveyance roller 8 as a conveyance means, and a recording sheet S which is a recording medium such as paper is conveyed by the conveyance roller 8. Note that the conveyance means for conveying the recording sheet S is not limited to the conveyance roller, and may be a belt, a drum, or the like.

  In the above-described example, the ink jet recording apparatus II has been exemplified in which the ink jet recording head I is mounted on the carriage 3 and moves in the main scanning direction, but the configuration is not particularly limited. The ink jet recording apparatus II may be, for example, a so-called line recording apparatus that performs printing by fixing the ink jet recording head I and moving a recording sheet S such as paper in the sub-scanning direction.

  In the above-described example, the ink jet recording apparatus II has a configuration in which the cartridges 2A and 2B, which are liquid storage means, are mounted on the carriage 3. The means may be fixed to the apparatus main body 4, and the liquid storage means and the ink jet recording head I may be connected via a supply pipe such as a tube. Further, the liquid storage means may not be mounted on the ink jet recording apparatus.

  In the above embodiment, an ink jet recording head has been described as an example of a liquid ejecting head, and an ink jet recording apparatus has been described as an example of a liquid ejecting apparatus. The present invention is intended for the entire apparatus, and can of course be applied to a liquid ejecting head and a liquid ejecting apparatus that eject liquid other than ink. 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 FED (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bio-organic matter ejection head used for biochip production, and the like, and can also be applied to a liquid ejection apparatus including such a liquid ejection head.

  The present invention is not limited to a piezoelectric actuator mounted on a liquid jet head typified by an ink jet recording head, but may be an ultrasonic device such as an ultrasonic transmitter, an ultrasonic motor, a pressure sensor, a pyroelectric sensor, or the like. It can also be applied to piezoelectric devices.

  I ink jet recording head (liquid ejecting head), II ink jet recording apparatus (liquid ejecting apparatus), 10 flow path forming substrate (substrate), 11 partition, 12 pressure generating chamber, 13 ink supply path, 14 communication path, 15 communication Part, 20 nozzle plate, 21 nozzle opening, 30 protective substrate, 31 piezoelectric element holding part, 32 manifold part, 33 through hole, 35 adhesive, 40 compliance board, 41 sealing film, 42 fixing plate, 43 opening part, 50 Diaphragm, 51 Elastic film, 52 Insulator film, 60 First electrode, 70 Piezoelectric layer, 71 First opening, 80 Second electrode, 81 First layer, 82, 82A Second layer, 84 Third opening 85 catalyst layer, 86 plating layer, 90 lead electrode, 100 manifold, 200 Force applying film, 201 second opening (opening), 210 compressive film, 220 resist, 300 piezoelectric elements, 310 active portion

Claims (12)

A substrate in which a plurality of recesses are partitioned by a partition;
A diaphragm provided on one side of the substrate;
A piezoelectric device provided on the surface of the diaphragm opposite to the substrate, the piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode laminated from the diaphragm side;
The piezoelectric element has an active portion that is provided in a region corresponding to the concave portion and serves as a substantial driving portion,
The first electrode constitutes an individual electrode provided individually in the active part,
The second electrode constitutes a common electrode provided in common to the plurality of active portions;
A stress applying film that extends to the upper surface of the second electrode opposite to the piezoelectric layer in a region facing the partition between the active parts adjacent to each other, and the internal stress becomes a tensile stress. Is provided,
A piezoelectric device characterized in that an opening is provided in a region corresponding to the central portion of the upper surface of the piezoelectric element for each active portion.   The piezoelectric device according to claim 1, wherein the stress applying film has a height from the diaphragm higher than that of the piezoelectric element.   The piezoelectric device according to claim 1 or 2, wherein the second electrode has a compressive stress as an internal stress.   The piezoelectric device according to any one of claims 1 to 3, wherein a compression film in which an internal stress becomes a compression stress is provided in the opening of the stress applying film.   5. The piezoelectric device according to claim 1, wherein a wiring having an internal stress serving as a tensile stress is provided on a surface opposite to the piezoelectric element of the stress applying film. .   The piezoelectric device according to claim 1, wherein the stress applying film is configured by laminating a plurality of layers.   The piezoelectric device according to claim 1, wherein the stress applying film is a photosensitive resin.   The piezoelectric device according to claim 1, wherein the concave portion is a pressure generation chamber, and has a nozzle opening communicating with the pressure generation chamber and ejecting a liquid. Liquid jet head.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 8. A substrate in which a plurality of recesses are partitioned by a partition;
A diaphragm provided on one side of the substrate;
A piezoelectric element that is provided on the surface of the diaphragm opposite to the substrate and in which the first electrode, the piezoelectric layer, and the second electrode are stacked from the diaphragm side;
The piezoelectric element has an active portion that is provided in a region corresponding to the concave portion and serves as a substantial driving portion,
The first electrode constitutes an individual electrode provided individually in the active part,
The second electrode constitutes a common electrode provided in common to the plurality of active portions;
In a region facing the partition between the active parts adjacent to each other, a stress applying film is provided which extends to the upper surface of the second electrode opposite to the piezoelectric layer and whose internal stress becomes tensile stress. And a method of manufacturing a piezoelectric device, wherein an opening is provided in a region corresponding to a central portion of the upper surface of the piezoelectric element.   The method of manufacturing a piezoelectric device according to claim 10, wherein the stress applying film is formed by a liquid phase method.   12. The method of manufacturing a piezoelectric device according to claim 10, wherein the second electrode is formed by a vapor phase method so that an internal stress is a compressive stress.

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