JP2014159115A - Liquid jet head and liquid jet device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid jet head and a liquid jet device having excellent liquid discharge characteristics.SOLUTION: A liquid jet head includes: a channel forming substrate 10 having a plurality of pressure generation chamber 12; a diaphragm 50 provided on a channel forming substrate 10; and piezoelectric devices 300 each having a first electrode 60 provided on the diaphragm 50, a piezoelectric layer 70 provided on the first electrode 60, and a second electrode 80 provided on the piezoelectric layer 70. The first electrode 60 configures an individual electrode that is independent for each of the piezoelectric devices 300. The second electrode 80 configures a common electrode that is common to the piezoelectric devices 300. The second electrode 80 forms a space part 301 between the second electrode 80 and a side surface of the piezoelectric layer 70 individually formed for each of the piezoelectric devices 300.

Description

  The present invention relates to a liquid ejecting head and a liquid ejecting apparatus, and more particularly to an ink jet recording head and an ink jet recording apparatus that eject ink as a liquid.

  2. Description of the Related Art Conventionally, a liquid ejecting head that ejects liquid droplets from a nozzle that communicates with a pressure generating chamber by deforming a piezoelectric element to cause pressure fluctuation in the liquid in the pressure generating chamber is known. A typical example is an ink jet recording head that ejects ink droplets as droplets.

  The ink jet recording head includes, for example, a piezoelectric element on one surface side of a flow path forming substrate provided with a pressure generating chamber communicating with a nozzle opening, and the diaphragm is deformed by driving the piezoelectric element so as to enter the pressure generating chamber. By causing a pressure change, an ink droplet is ejected from the nozzle.

  Such a piezoelectric element includes a first electrode, a piezoelectric layer, and a second electrode provided on the diaphragm (see, for example, Patent Document 1). The first electrode constitutes an independent individual electrode for each of the plurality of piezoelectric elements, and the second electrode constitutes a common electrode common to the plurality of piezoelectric elements.

JP 2009-172878 A

  However, the second electrode is formed in close contact with each piezoelectric layer, and deformation of the piezoelectric element is restricted. As the deformation of the piezoelectric element is constrained in this way, the amount of displacement of the diaphragm is lowered, and there is a possibility that the ink ejection characteristics are also lowered.

  Such a problem exists not only in an ink jet recording head but also in a liquid ejecting head that ejects liquid other than ink.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting head and a liquid ejecting apparatus having high liquid ejection characteristics.

An aspect of the present invention that solves the above problems includes a flow path forming substrate including a plurality of pressure generation chambers that communicate with a nozzle opening that discharges a liquid, a vibration plate provided on the flow path formation substrate, and the vibration plate A piezoelectric element having a first electrode provided on the piezoelectric element, a piezoelectric layer provided on the first electrode, and a second electrode provided on the piezoelectric layer, wherein the first electrode is the piezoelectric element. The individual electrode that is independent for each element, the second electrode is a common electrode common to the plurality of piezoelectric elements, and the second electrode is the piezoelectric layer formed individually for each piezoelectric element The liquid ejecting head is characterized in that a space is formed between the side surfaces of the liquid ejecting head.
In such an aspect, the piezoelectric element has a space formed between the second electrode and the piezoelectric layer. That is, the portion where the second electrode is bonded to the piezoelectric layer is limited to the upper surface of the piezoelectric layer necessary for constituting the active portion of the piezoelectric element. For this reason, the restraining force that the second electrode inhibits the deformation of the piezoelectric element is reduced as compared with the piezoelectric element having the conventional configuration in which the second electrode is in close contact with the entire surface of the piezoelectric layer.
Therefore, the piezoelectric element having the space portion has an improved displacement amount of the piezoelectric element as compared with the piezoelectric element of the conventional configuration, and by providing the piezoelectric element with the improved displacement amount, the liquid ejecting head discharges the liquid. Characteristics can be improved.

  Here, the second electrode includes a first layer formed on the piezoelectric layer and a second layer formed on the first layer, and the first layer is provided for each of the piezoelectric elements. Projecting laterally from above the piezoelectric layer and forming the space between the piezoelectric layer and the side surface of the piezoelectric layer to contact the diaphragm, and the second layer is formed for each piezoelectric element It is preferable that the first layer is formed in common. According to this, it is possible to prevent the space portion from being crushed.

  The diaphragm includes an arm portion facing an end portion in the width direction of the pressure generation chamber, and the second electrode includes the space portion between a side surface of the piezoelectric layer and the arm portion. It is preferable to form. According to this, it is possible to prevent the displacement of the region facing the pressure generation chamber of the diaphragm from being inhibited by the second electrode. Thereby, the displacement of the diaphragm is further improved, and the ejection characteristics of the liquid jet head are further improved.

Furthermore, another aspect of the invention resides in a liquid ejecting apparatus including the liquid ejecting head described in the above aspect.
In this aspect, a liquid ejecting apparatus having high liquid ejection characteristics is provided.

1 is a perspective view of an ink jet recording head according to Embodiment 1. FIG. 2A and 2B are a plan view and a cross-sectional view of the ink jet recording head according to Embodiment 1. 2 is an enlarged cross-sectional view of a main part of the piezoelectric element according to Embodiment 1. FIG. 2 is an enlarged cross-sectional view of a main part of the piezoelectric element according to Embodiment 1. FIG. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. 6 is a cross-sectional view of a piezoelectric element according to Embodiment 2. FIG. 1 is a schematic view of an ink jet recording apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<Embodiment 1>
FIG. 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 and a cross-sectional view of the ink jet recording head.

  As shown in the figure, the ink jet recording head I according to this embodiment includes a flow path forming substrate 10. A pressure generating chamber 12 partitioned by a plurality of partition walls 11 is formed in the flow path forming substrate 10. The pressure generation chambers 12 are arranged side by side along a direction in which a plurality of nozzle openings 21 that eject 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, a direction orthogonal to the first direction X is defined as a second direction Y in the plane of the flow path forming substrate 10. Furthermore, a direction orthogonal to the first direction X and the second direction Y is defined as a third direction Z. Although one row of the pressure generation chambers 12 arranged in parallel in the first direction X is shown in the drawing, a plurality of rows of the pressure generation chambers 12 may be arranged in the second direction Y. .

  An ink supply path 13 and a communication path 14 are partitioned by a plurality of partition walls 11 on one end side in the second direction Y of the pressure generating chamber 12 of the flow path forming substrate 10. 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. Further, a part of the flow path forming substrate 10 can be processed thinly and used as an elastic film of the diaphragm. 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 piezoelectric element 300 including the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is formed. In this embodiment, the piezoelectric element 300 provided on the flow path forming substrate 10 functions as an actuator device.

  Hereinafter, the piezoelectric element 300 constituting the actuator device will be described in detail. FIG. 3A is an enlarged cross-sectional view of the main part of the piezoelectric element according to Embodiment 1 of the present invention, and FIG. 3B is a cross-sectional view taken along the line BB ′ of FIG. .

  As shown in FIG. 3, the first electrode 60 constituting the piezoelectric element 300 is separated 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 generation chamber 12 in the first direction X of the pressure generation chamber 12. 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 of the pressure generation chamber 12, 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 not particularly limited as long as it is a metal material. For example, metals such as Ti, Pt, Ta, Ir, Sr, In, Sn, Au, Al, Fe, Cr, Ni, and Cu are used. Alternatively, only one of these materials, or a mixture or stack of two or more of these materials may be used as the first electrode 60.

  The piezoelectric layer 70 is continuously provided over 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 addition, the piezoelectric layer 70 is formed with a recess 71 that faces each partition wall 11. The piezoelectric layer 70 is continuously formed across the pressure generation chambers 12 along the first direction X, and a portion facing the partition walls 11 is removed to form a recess 71. The concave portion 71 suppresses the rigidity of the portion (the arm portion 54 of the vibration plate 50) facing the width direction end of the pressure generation chamber 12 of the vibration plate 50, so that the piezoelectric element 300 can be favorably displaced.

  The end portion of the piezoelectric layer 70 on one end side in the second direction Y of the pressure generation chamber 12 (in the present embodiment, on the ink supply path 13 side) is located outside the end portion of the first electrode 60. Yes. That is, the end portion of the first electrode 60 is covered with the piezoelectric layer 70. The end portion of the piezoelectric layer 70 on the other end side in the second direction Y of the pressure generation chamber 12 is located on the inner side (the pressure generation chamber 12 side) than the end portion of the first electrode 60.

  Note that a lead electrode 90 (see FIGS. 1 and 2) made of, for example, gold (Au) or the like is connected to the first electrode 60 extended to the outside 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.

Examples of the piezoelectric layer 70 include a perovskite structure crystal film (perovskite crystal) 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. Specifically, lead titanate (PbTiO ₃ ), lead zirconate titanate (Pb (Zr, Ti) O ₃ ), lead zirconate (PbZrO ₃ ), lead lanthanum titanate ((Pb, La), TiO ₃ ) ), Lead lanthanum zirconate titanate ((Pb, La) (Zr, Ti) O ₃ ), lead magnesium titanate zirconate titanate (Pb (Zr, Ti) (Mg, Nb) O ₃ ), etc. Can do. In the present embodiment, lead zirconate titanate (PZT) is used as the piezoelectric layer 70.

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. Examples of lead-free piezoelectric materials include bismuth ferrate ((BiFeO ₃ ), approximately “BFO”), barium titanate ((BaTiO ₃ ), approximately “BT”), and sodium potassium niobate ((K, Na). ) (NbO ₃ ), approximately “KNN”), potassium sodium niobate lithium ((K, Na, Li) (NbO ₃ )), potassium sodium tantalate niobate ((K, Na, Li) (Nb, Ta) ) O ₃ ), potassium bismuth titanate ((Bi _1/2 K _1/2 ) TiO ₃ , approximately “BKT”), sodium bismuth titanate ((Bi _1/2 Na _1/2 ) TiO ₃ , approximately “BNT” "), bismuth manganate (BiMnO _3, substantially" BM "), bismuth, potassium, composite oxides having a perovskite structure that contains titanium and iron _{(x [(Bi x K 1} -x) TiO 3] - (1 x) [BiFeO _3], approximately "BKT-BF"), bismuth, iron, composite oxide having a perovskite structure containing barium and titanium ((1-x) [BiFeO 3] -x [BaTiO 3], approximately " BFO-BT ”) or a metal added with manganese, cobalt, chromium or the like ((1-x) [Bi (Fe _1-y M _y ) O ₃ ] -x [BaTiO ₃ ] (M is Mn, Co or Cr)).

  The second electrode 80 is continuously provided on the piezoelectric layer 70 in the first direction X of the pressure generating chamber 12 and constitutes a common electrode common to the plurality of piezoelectric elements 300. The material of the 2nd electrode 80 will not be specifically limited if it is a metal material, For example, the material similar to the 1st electrode 60 can be used.

  The end portion of the second electrode 80 on one end side in the second direction Y of the pressure generating chamber 12 is located outside the end portion of the piezoelectric layer 70. That is, the end portion of the piezoelectric layer 70 is covered with the second electrode 80. Further, the end portion of the second electrode 80 on the other end side in the second direction Y of the pressure generation chamber 12 is located on the inner side (pressure generation chamber 12 side) than the end portion of the piezoelectric layer 70.

  The piezoelectric element 300 having such a configuration 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 320. On the other hand, a portion where no piezoelectric distortion occurs in the piezoelectric layer 70 is referred to as an inactive portion. In the active part 320 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 of the pressure generation chamber 12. That is, the active part 320 is continuously provided to the outside of the pressure generating chamber 12. For this reason, a portion of the active portion 320 facing 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.

  Here, the space 301 formed by the second electrode 80 and the second electrode 80 will be described in detail with reference to FIGS. 3 and 4. FIG. 4 is an enlarged cross-sectional view of the main part of the piezoelectric element.

  A space 301 is formed between the second electrode 80 and the side surface of the piezoelectric layer 70. That is, the second electrode 80 has a diaphragm 50 (a region facing the partition wall 11) that appears as a bottom of the recess 71 without being in close contact with the side surface of the piezoelectric layer 70 from the upper surface of the piezoelectric layer 70 constituting the active part 320. ) Is formed over.

  As described above, the second electrode 80 is formed on the piezoelectric layer 70 and the vibration plate 50 without being in close contact with the side surface of the piezoelectric layer 70, so that a space is formed between the second electrode 80 and the piezoelectric layer 70. A portion 301 is formed.

  The second electrode 80 according to the present embodiment includes a first layer 81 formed on the piezoelectric layer 70 and a second layer 82 formed on the first layer 81. The first layer 81 and the second layer 82 are each formed of an electrode material that can be applied to the second electrode 80 described above. The electrode material of the first layer 81 and the second layer 82 may be the same or different.

  The first layer 81 protrudes laterally (first direction X) from the upper surface of the piezoelectric layer 70, and the tip thereof is in contact with the diaphragm 50. That is, in the first direction X, the first layer 81 is not continuous with other adjacent piezoelectric elements 300 and is formed independently for each piezoelectric element 300.

  The second layer 82 is formed in common on the first layer 81 formed for each piezoelectric element 300, and is formed so as to cover the diaphragm 50 that appears in the recess 71. That is, the second layer 82 is formed continuously with each piezoelectric element 300 in the first direction X.

  The piezoelectric element 300 configured as described above has a space 301 between the second electrode 80 and the piezoelectric layer 70. That is, the second electrode 80 is not in close contact with the entire surface of the piezoelectric layer 70.

  Thus, the portion where the second electrode 80 is bonded to the piezoelectric layer 70 is limited to the upper surface of the piezoelectric layer 70 necessary for configuring the active part 320. For this reason, the restraining force that the second electrode 80 inhibits the deformation of the piezoelectric element 300 is reduced as compared with the piezoelectric element of the conventional configuration in which the second electrode 80 is in close contact with the entire surface of the piezoelectric layer 70.

  Therefore, the piezoelectric element 300 having the space portion 301 has an improved displacement amount of the piezoelectric element 300 as compared with the piezoelectric element having the conventional configuration. By including the piezoelectric element 300 having an improved displacement in this manner, the ink ejection characteristics of the ink jet recording head I can be improved.

  Note that the second electrode 80 is provided only on the upper surface of the piezoelectric layer 70 and the second electrode 80 is not provided on the side surface of the piezoelectric layer 70, that is, a space between the second electrode 80 and the side surface of the piezoelectric layer 70. A configuration in which the part 301 is not provided is also conceivable.

  In the case of this configuration, although the restraining force by the second electrode 80 can be reduced, the electrical resistance increases as the area of the second electrode 80 decreases. The piezoelectric element 300 according to the present embodiment can reduce the restraining force by the second electrode 80 without increasing the electrical resistance as such.

  In the piezoelectric element 300 according to the present embodiment, the second electrode 80 includes the first layer 81 and the second layer 82. The portion of the first layer 81 forming the space 301 has an arch shape that is convex upward. On the other hand, the movement of the front end portion of the first layer 81 in contact with the diaphragm 50 is restricted by the second layer 82. That is, since the first layer 81 is maintained in an arch shape, the space portion 301 formed by the second electrode 80 can be prevented from being crushed.

  Further, the portion where the second electrode 80 contacts the diaphragm 50 is a region facing the partition wall 11 of the diaphragm 50. That is, the arm portion 54 of the diaphragm 50 is not in contact with the second electrode 80 (first layer 81), the side surface of the piezoelectric layer 70, and the arm portion 54, thereby forming a space portion 301. Thereby, the displacement of the diaphragm 50 including the arm portion 54 can be prevented from being inhibited by the second electrode 80, and the displacement of the diaphragm 50 can be further improved.

  As shown in FIGS. 1 and 2, a protective substrate 30 that protects the piezoelectric element 300 is bonded to the flow path forming substrate 10 on which the piezoelectric element 300 is formed 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 piezoelectric element 300 is exposed in the through hole 33. One end of a connection wiring connected to a drive circuit (not shown) is connected to the lead electrode 90 connected to the first electrode 60 of each piezoelectric element 300 in the through hole 33.

  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, ink is taken in from an ink inlet connected to an external ink supply means (not shown), and the interior of the liquid flow path is filled with ink from the manifold 100 to the nozzle opening 21. Thereafter, 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 a recording signal from the drive circuit. 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 according to the present embodiment will be described. 5 to 8 are cross-sectional views in the first direction X showing the method of manufacturing the ink jet recording head.

  First, as shown in FIG. 5A, an elastic film 51 is formed on the surface of a flow path forming substrate wafer 110 that is a silicon wafer. In the present embodiment, the elastic film 51 made of silicon dioxide is formed by thermally oxidizing the flow path forming substrate wafer 110. Of course, the method of forming the elastic film 51 is not limited to thermal oxidation, and may be formed by sputtering, CVD, or the like.

  Next, as shown in FIG. 5B, an insulator film 52 made of zirconium oxide is formed on the elastic film 51. The insulator film 52 may be formed by thermally oxidizing zirconium after being formed by sputtering or the like, or zirconium oxide may be formed by reactive sputtering. A diaphragm 50 is formed by the elastic film 51 and the insulator film 52.

  Next, as shown in FIG. 5C, the 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, 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 this reason, platinum, iridium, etc. are used suitably as a material of the 1st electrode 60. FIG. The first electrode 60 can be formed by, for example, a sputtering method, a PVD method (physical vapor deposition method), an electroless plating method, or the like.

  Next, as shown in FIG. 6A, the first electrode 60 is patterned. The patterning can be performed by dry etching such as ion milling, for example.

Although not particularly shown, a crystal seed layer made of titanium (Ti) may be formed on the first electrode 60. By providing the crystal seed layer on the first electrode 60, when the piezoelectric layer 70 is formed on the first electrode 60 via the crystal seed layer, the preferred orientation direction of the piezoelectric layer 70 is set to (100). The piezoelectric layer 70 that can be controlled and is suitable as an electromechanical conversion element can be obtained. As the crystal seed layer, titanium (Ti) or titanium oxide (TiO ₂ ) may be used, and materials other than titanium and titanium oxide, 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.

  As a specific procedure for forming the piezoelectric layer 70, first, as shown in FIG. 6B, a piezoelectric precursor film 73 which is a PZT precursor film is formed on the first electrode and the insulator film 52. To do. That is, a sol (solution) containing a metal complex is applied onto the flow path forming substrate wafer 110 on which the first electrode 60 is formed (application step). 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 73 is heated to a predetermined temperature and dried for a predetermined time (drying step). For example, in the present embodiment, the piezoelectric precursor film 73 can be dried by holding at 170 to 180 ° C. for 8 to 30 minutes.

Next, the dried piezoelectric precursor film 73 is degreased by heating to a predetermined temperature and holding for a certain time (degreasing step). For example, in this embodiment, the piezoelectric precursor film 73 is degreased by heating to a temperature of about 300 to 400 ° C. and holding for about 10 to 30 minutes. Note that the degreasing here, the organic components contained in the piezoelectric precursor film 73, for _example, is to be detached as _{NO 2, CO 2, H 2} O or the like.

  Next, the piezoelectric precursor film 73 is crystallized by being heated to a predetermined temperature and held for a predetermined time, thereby forming the piezoelectric film 74 (firing process). In this firing step, the piezoelectric precursor film 73 is preferably heated to 700 ° C. or higher. In the firing step, it is preferable that the temperature rising rate is 50 ° C./sec or more. Thereby, the piezoelectric film 74 having excellent characteristics can be obtained.

  As shown in FIG. 6C, the piezoelectric layer 70 composed of a plurality of layers of piezoelectric films 74 is formed by repeating the piezoelectric film forming process including the coating process, the drying process, the degreasing process, and the baking process described above a plurality of times. Form. The piezoelectric film 74 may be formed one layer at a time, or a plurality of layers may be formed by repeating a coating process, a drying process, and a degreasing process to form a plurality of piezoelectric precursor films 73 and performing a baking process on them. Alternatively, the piezoelectric film 74 may be formed.

  In addition, as a heating apparatus used in such a drying process, a degreasing process, and a baking process, for example, a hot plate, an RTP (Rapid Thermal Processing) apparatus that heats by irradiation with an infrared lamp, or the like can be used.

  Next, although not particularly shown, a first layer 81 constituting the second electrode 80 is formed on the entire surface of the piezoelectric layer 70. The first layer 81 can be formed in the same manner as the first electrode 60.

  Next, a resist film 78 is formed on the first layer 81 in each region where the piezoelectric elements 300 of the piezoelectric layer 70 are formed by photolithography.

  Specifically, first, a resist film 78 is formed on the entire surface of the first layer 81, and an opening 79 is formed so that the first layer 81 is exposed in a region where the recess 71 (see FIGS. 1 to 4) is formed. To do. Then, the first layer 81 exposed in the opening 79 is etched by dry etching to expose the piezoelectric layer 70.

  Next, as shown in FIG. 7A, the piezoelectric layer 70 is patterned into regions facing the pressure generation chambers 12 by wet etching. A known method can be used for wet etching. For example, a BHF 20% solution, a mixed solution of nitric acid and hydrochloric acid can be used. In addition, a two-step process in which wet etching is performed only with a BHF 20% solution and a residue is removed with nitric acid can be used.

  The wet etching of the piezoelectric layer 70 proceeds in the thickness direction (third direction Z) of the piezoelectric layer 70 from the opening 79 of the resist film 78, and in the width direction (first direction X). Also proceeds (side etching). Thereby, the piezoelectric layer 70 is patterned into a substantially trapezoidal shape. At this time, the surface of the first layer 81 opposite to the resist film 78 is exposed. That is, the first layer 81 is in a state where the entire one surface is in contact with the resist film 78 and the other surface is partially in contact with the upper surface of the piezoelectric layer 70.

  The patterning of the piezoelectric layer 70 is not limited to wet etching, and may be performed by dry etching.

  Next, as shown in FIG. 7B, the resist film 78 is removed. As a result, both ends of the first layer 81 in the first direction X are unconstrained and contact the diaphragm 50. The first layer 81 has an arch shape that protrudes upward, and a space 301 is formed between the first layer 81 and the side surface of the piezoelectric layer 70. Although not particularly illustrated, the arch-shaped first layer 81 is similarly formed in the second direction Y in the recess 71.

  Next, as shown in FIG. 7C, the second electrode 80 is formed by forming the second layer 82 on the first layer 81 and the diaphragm 50. The second layer 82 can be formed in the same manner as the first electrode 60.

  In this way, the second electrode 80 common to the piezoelectric layers 70 is formed, and a plurality of piezoelectric elements 300 having the space 301 are formed.

  Next, the lead electrode 90 is formed. Although not specifically shown, after the lead electrode 90 made of, for example, gold (Au) is formed over the entire surface of the flow path forming substrate wafer 110, the piezoelectric film is formed via a mask pattern (not shown) made of, for example, a resist. Each element 300 is formed by patterning.

  Next, as shown in FIG. 8A, a protective substrate wafer 130 which is a silicon wafer and serves as a plurality of protective substrates 30 is attached to the piezoelectric element 300 side of the flow path forming substrate wafer 110 with an adhesive 35 (FIG. 2). After joining via (b), the flow path forming substrate wafer 110 is thinned to a predetermined thickness.

  Next, as shown in FIG. 8B, 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. 8C, 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.

  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>
In the method for manufacturing the ink jet recording head I, another aspect of the step of patterning the piezoelectric layer 70 and forming the second electrode 80 (first layer 81) will be described.

  FIG. 9 is a cross-sectional view in the first direction X of the piezoelectric element according to the present embodiment. In addition, the same code | symbol is attached | subjected to the same thing as Embodiment 1, and the overlapping description is abbreviate | omitted.

  First, the first electrode 60 is formed on the vibration plate 50, and the piezoelectric layer 70 is formed (see FIGS. 5 to 6B).

  Next, as shown in FIG. 9A, the piezoelectric layer 70 is patterned. This patterning is performed by dry etching or wet etching.

  Next, as shown in FIG. 9B, the recesses 71 between the piezoelectric layers 70 are filled with the sacrificial layer 72, and the first layer 81 and the resist film 78 constituting the second electrode 80 are formed.

  Specifically, a sacrificial layer 72 made of an etchable material is formed in the recess 71 so that the sacrificial layer 72 is substantially flush with the piezoelectric layer 70. Next, the first layer 81 constituting the second electrode 80 is formed on the entire surface of the upper surface of the piezoelectric layer 70 and the upper surface of the sacrificial layer 72. Then, as in the first embodiment, a resist film 78 is formed on the first layer 81, and an opening 79 is formed in a region facing the recess 71. Further, the first layer 81 appearing in the opening 79 is removed to expose the sacrificial layer 72.

  Next, as shown in FIG. 9C, the sacrificial layer 72 is removed by wet etching or the like. As a result, the piezoelectric layer 70 patterned in a substantially trapezoidal shape appears, and the surface of the first layer 81 opposite to the resist film 78 is exposed. That is, the first layer 81 is in a state where the entire one surface is in contact with the resist film 78 and the other surface is partially in contact with the upper surface of the piezoelectric layer 70.

  Although not shown in particular, by removing the resist film 78, the first layer 81 is bent toward the diaphragm 50, and the second layer 82 is formed on the first layer 81 to form the second electrode 80. (Same as in FIGS. 7B to 7C).

  As described above, the space 301 is formed between the first layer 81 and the piezoelectric layer 70 by first patterning the piezoelectric layer 70 and then forming and removing the sacrificial layer 72. be able to.

<Other embodiments>
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.

  The second electrode 80 forms the space 301 without being in close contact with the entire side surface of the piezoelectric layer 70, but is not limited to such a mode. For example, the second electrode 80 may be in close contact with a part of the side surface of the piezoelectric layer 70 and may not be in close contact with the remaining part to form the space.

  Further, the second electrode 80 is not limited to the one composed of the first layer 81 and the second layer 82. For example, the second layer 80 may be formed by forming only the first layer 81 without forming the second layer 82. In this case, as shown in FIG. 3, the second electrode 80 is not continuous in the region facing the pressure generation chamber 12 and the partition wall 11. However, since the second electrode 80 is continuous in a region facing the ink supply path 13 and the communication path 14 and a region in the vicinity of the lead electrode 90 (see FIGS. 1 and 2), the function as a common electrode is ensured. be able to.

  The ink jet recording head I is mounted on an ink jet recording apparatus II, for example, as shown in FIG. The ink jet recording apparatus II includes an apparatus main body 4, and a carriage shaft 5 is attached to the apparatus main body 4. A carriage 3 is provided on the carriage shaft 5 so as to be movable in the axial direction. A cartridge 2 constituting an ink supply means is detachably provided on the carriage 3 and an ink jet recording head I is attached thereto.

  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 ink jet recording head I is mounted is moved along the carriage shaft 5. . On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S that is a recording medium such as paper fed by a paper feed roller (not shown) is wound around the platen 8. It is designed to be transported.

  In the present invention, as described above, since the ink jet recording head I is excellent in ink ejection characteristics, an ink jet recording apparatus II with improved print quality can be realized.

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

  Furthermore, the present invention can be applied not only to such a liquid jet head (inkjet recording head) but also to an actuator device mounted on any device. The actuator device of the present invention can be applied to various sensors, for example.

  I ink jet recording head (liquid ejecting head), II ink jet recording apparatus (liquid ejecting apparatus), 10 flow path forming substrate, 12 pressure generating chamber, 20 nozzle plate, 21 nozzle opening, 50 vibration plate, 54 arm part, 60 First electrode, 70 piezoelectric layer, 71 concave portion, 73 piezoelectric precursor film, 74 piezoelectric film, 80 second electrode, 81 first layer, 82 second layer, 300 piezoelectric element, 301 space portion, 320 active portion

Claims (4)

A flow path forming substrate comprising a plurality of pressure generating chambers communicating with nozzle openings for discharging liquid;
A diaphragm provided on the flow path forming substrate;
A first electrode provided on the diaphragm, a piezoelectric layer provided on the first electrode, and a piezoelectric element having a second electrode provided on the piezoelectric layer,
The first electrode constitutes an individual electrode independent for each piezoelectric element;
The second electrode constitutes a common electrode common to the plurality of piezoelectric elements;
The liquid ejecting head, wherein the second electrode forms a space portion with a side surface of the piezoelectric layer formed individually for each of the piezoelectric elements. The liquid ejecting head according to claim 1,
The second electrode includes a first layer formed on the piezoelectric layer, and a second layer formed on the first layer,
For each of the piezoelectric elements, the first layer protrudes laterally from above the piezoelectric layer and forms a space between the piezoelectric layer and a side surface of the piezoelectric layer, and contacts the diaphragm.
The liquid ejecting head, wherein the second layer is formed in common on the first layer formed for each of the piezoelectric elements. The liquid ejecting head according to claim 1 or 2,
The diaphragm has an arm portion facing an end in the width direction of the pressure generating chamber,
The liquid ejecting head, wherein the second electrode forms the space portion between a side surface of the piezoelectric layer and the arm portion.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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