JP6183601B2 - Piezoelectric element, liquid ejecting head, liquid ejecting apparatus, ultrasonic device, filter and sensor, and method for manufacturing piezoelectric element - Google Patents

Description

  The present invention relates to a liquid ejecting head that ejects liquid from a nozzle opening, a liquid ejecting apparatus that includes the liquid ejecting head, a piezoelectric element mounted on the liquid ejecting head, and the like, and a method for manufacturing the same.

  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 diaphragm, and the first electrode and the second electrode are connected to a wiring connected to a driving IC or the like. For example, Patent Documents 1 to 3 may be used.

JP 2008-114370 A JP 2009-172878 A JP 2009-196329 A

  As the wiring layer, copper or a copper alloy is used for the purpose of cost reduction. However, since copper is easily oxidized and easily migrated, an electroless plating layer by electroless plating is usually provided on the wiring layer as a protective layer via a metal catalyst. However, even if such a protective layer is provided, the migration of copper cannot be suppressed, and the potential of the metal catalyst moves to the vicinity of the electrode together with the potential of copper, and the region other than the region to be electrolessly plated through this metal catalyst. There is a problem that an electroless plating layer is deposited. Such deposition of the electroless plating layer causes a decrease in the displacement of the piezoelectric element.

  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. Further, the present invention is not limited to the piezoelectric element mounted on the liquid ejecting head, and similarly exists in the piezoelectric element mounted on other devices.

  In view of such circumstances, the present invention prevents a deposition of an electroless plating layer in a region other than an electroless plating region and suppresses a decrease in displacement, a liquid ejecting head, a liquid ejecting apparatus, a piezoelectric element, and a production thereof It aims to provide a method.

An aspect of the present invention for solving the above-described problems is provided on the second electrode, the first electrode, the second electrode, the piezoelectric layer disposed between the first electrode and the second electrode, and the second electrode. A piezoelectric element comprising a wiring layer containing copper and an electroless plating layer provided on the wiring layer via a catalyst layer, wherein the piezoelectric element is on the end side of the wiring layer on the second electrode. The piezoelectric element is characterized in that an electroless plating layer is not provided.
In such an embodiment, the region other than the region to be electrolessly plated, specifically, the end side of the wiring layer on the second electrode, the region on the piezoelectric layer where the wiring layer is not provided, and the region on the second electrode. Thus, a piezoelectric element that prevents the electroless plating layer from being deposited and suppresses a decrease in the displacement amount is realized.

  Here, the catalyst layer is preferably palladium formed from a catalyst solution containing palladium ions. According to this, the electroless plating layer can be reliably and selectively formed on the wiring layer containing copper.

Here, it is preferable that the electroless plating layer includes a nickel layer containing nickel formed by electroless plating and a gold layer containing gold formed by electroless plating above the nickel layer.
According to this, the electrical resistance value can be lowered by the nickel layer, and the mounting strength when the external wiring is mounted on the wiring layer by the gold layer can be ensured.

Here, it is preferable that a palladium layer formed by electroless plating is further provided between the nickel layer and the gold layer.
According to this, the diffusion of nickel in the nickel layer and gold in the gold layer is prevented.

Here, it is preferable that an adhesion layer including at least one of titanium and tungsten is provided on the second electrode side of the wiring layer.
According to this, since the adhesion layer contains at least one of titanium and tungsten, it is possible to suppress the occurrence of electrolytic corrosion on the electrode by the etching solution when the adhesion layer is wet etched. Peeling can be suppressed. In addition, since an etching solution other than an acid can be used when etching the adhesion layer, the piezoelectric layer can be prevented from being damaged by the etching solution.

Here, the first electrode constitutes an individual electrode provided for each active part serving as a substantial driving part of the piezoelectric element, and the second electrode is a common electrode common to the plurality of active parts. It is preferable to configure.
According to this, the first electrode can be covered with the piezoelectric layer, and the protective film for suppressing the leakage current due to the close proximity of the first electrode and the second electrode becomes unnecessary, and the protective film is made of the piezoelectric element. A liquid ejecting head including a piezoelectric element having excellent displacement characteristics can be realized without hindering displacement.

Further, according to another aspect of the present invention, there is provided a flow path forming substrate having a pressure generation chamber communicating with a nozzle opening for ejecting liquid, and any one of the above aspects provided on one surface side of the flow path forming substrate. And a piezoelectric element as described above.
In this aspect, a liquid ejecting head that prevents deposition of the electroless plating layer in a region other than the region where electroless plating is performed and suppresses a decrease in displacement is realized.
According to another aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head according to any one of the above aspects.
In this aspect, a liquid ejecting apparatus that prevents the electroless plating layer from being deposited in a region other than the region where electroless plating is performed and suppresses a decrease in the amount of displacement is realized.

Furthermore, another aspect of the present invention resides in an ultrasonic device, filter or sensor comprising the piezoelectric element according to any one of the above aspects. In such an embodiment, generation of cracks is suppressed, and an ultrasonic device, filter, or sensor having a piezoelectric layer having excellent crystallinity and piezoelectric characteristics can be obtained.
In such an embodiment, an ultrasonic device, filter, or sensor that prevents the electroless plating layer from being deposited in a region other than the region to be electrolessly plated and suppresses a decrease in the amount of displacement is realized.

Yet another embodiment of the present invention includes a first electrode, a second electrode, a piezoelectric layer provided between the second electrode and the first electrode, provided on the second electrode A method of manufacturing a piezoelectric element comprising a wiring layer containing copper and an electroless plating layer provided on the wiring layer via a catalyst layer, wherein a conductive layer containing copper is formed on the second electrode Forming a wiring layer by patterning the conductive layer by etching, providing a resist layer above the piezoelectric layer and the second electrode, and patterning the region to be electrolessly plated. A step of exposing, a step of forming a catalyst layer made of palladium using a catalyst solution containing palladium ions on the exposed electroless plating region, and nickel containing nickel by electroless plating on the catalyst layer Worker to form a layer If, in the manufacturing method of the piezoelectric element characterized by comprising a step of forming a gold layer containing gold by electroless plating over the nickel layer, removing the resist, a.
In such an embodiment, a piezoelectric element is produced in which the electroless plating layer is prevented from being deposited in a region other than the region where electroless plating is performed, and the decrease in displacement is suppressed.

Here, it is preferable that the method further includes a step of forming a palladium layer on the nickel layer by electroless plating after the step of forming the nickel layer.
According to this, the diffusion of nickel in the nickel layer and gold in the gold layer is prevented.

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. 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. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first 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 corresponding to the line AA ′ in FIG. 2 and an enlarged cross-sectional view, FIG. 4 is a cross-sectional view corresponding to the line BB ′ in FIG. 2, and FIG. It is sectional drawing according to a 'line.

  As shown in the drawing, a pressure generating chamber 12 is formed in a flow path forming substrate 10 provided in an ink jet recording head I which is an example of a liquid ejecting head of the present 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.

  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. The second electrode 80, which will be described in detail with reference to FIGS. 3 and 4, is a lead electrode 90 that is a wiring layer provided on the second electrode, and a catalyst layer 193 on the lead electrode 90 (wiring layer). A piezoelectric element 300 composed of an electroless plating layer including a nickel layer 194, a palladium layer 195, and a gold layer 196 is provided. The piezoelectric element 300 that is deformably provided on the substrate (the flow path forming substrate 10) is the piezoelectric actuator of the present embodiment.

Hereinafter, the piezoelectric element 300 that is a piezoelectric actuator will be described in more detail with reference to FIGS. 3 and 4.
As shown in the figure, the first electrode 60 constituting the piezoelectric element 300 is divided for each pressure generating chamber 12 and constitutes an individual electrode that is independent for each active portion described later. 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. 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 must be a material that does not oxidize when the piezoelectric layer 70 described later is formed and can maintain conductivity. For example, platinum (Pt), iridium (Ir) ) Or 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 oxide, or the like can be used in addition to titanium. 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 13 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. 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 lithium niobate ((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”), bismuth sodium titanate ((Bi _1/2 Na _1/2 ) TiO ₃ , approximately “BNT )), Bismuth manganate (BiMnO ₃ , approximately “BM”), bismuth, potassium, titanium and iron, and a composite oxide having a perovskite structure (x [(B _{i 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 ], substantially “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)).

  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 such a piezoelectric layer 70, recesses 71 corresponding to the respective partition walls 11 are formed. The width of the recess 71 in the first direction X is substantially the same as or wider than the width of each partition 11 in the first direction. As a result, the rigidity of the portion of the vibration plate 50 that opposes the end portion of the pressure generation chamber 12 in the second direction Y (the arm portion of the vibration plate 50) is suppressed, so that the piezoelectric element 300 can be favorably displaced. it can.

  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 capable of satisfactorily forming an interface with the piezoelectric layer 70 and exhibiting piezoelectric characteristics, such as iridium (Ir), platinum (Pt), palladium (Pd), gold (Au), titanium ( A metal material such as Ti) and a conductive oxide represented by lanthanum nickel oxide (LNO) are preferably used. The first layer 81 may be a stacked layer of a plurality of materials. In this embodiment, a laminate of iridium and titanium (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), gold (Au), titanium (Ti) or the like. Materials can be used. 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 laminate of iridium and titanium (iridium is in contact with the first layer 81) 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. 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.

  The 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, as shown in FIG. 5, 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. Incidentally, even if the first electrode 60 and the second electrode 80 are exposed, current leakage does not occur unless the distance is short.
The individual lead electrode 91 and the common lead electrode 92 which are the wiring layers of the present embodiment are connected to the first electrode 60 and the second electrode 80 of the piezoelectric element 300.

  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 flow path forming substrate 10 side and a conductive layer 192 provided on the adhesion layer 191.

The adhesion layer 191 is for improving the adhesion between the second electrode 80, the first electrode 60, the diaphragm 50, and the conductive layer 192, and includes at least one of titanium (Ti) and tungsten (W). Made of material. In this embodiment, titanium tungsten (TiW) is used as the adhesion layer 191.
The conductive layer 192 is provided over the adhesion layer 191 and is formed of a material containing copper (Cu). In this embodiment, copper (Cu) is used as the conductive layer 192.
Here, the individual lead electrode 91 is drawn from the first electrode 60 provided outside the piezoelectric layer 70 to the diaphragm 50.

As shown in FIG. 4, the common lead electrode 92 is drawn in the second direction Y from the second electrode 80 to the diaphragm 50 at both ends in the first direction X.
In addition, the common lead electrode 92 extends in the second direction Y on the wall surface of the pressure generating chamber 12, that is, the extended portion 93 (see FIG. 5) provided across the boundary portion between the flexible portion and the non-flexible portion. 2). 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.
As will be described in detail later, such a lead electrode 90 is formed by patterning into a predetermined shape after being formed over the entire one surface of the flow path forming substrate 10.

  At this time, since the adhesion layer 191 of this embodiment is formed of titanium tungsten (TiW), not an acid but an alkali such as hydrogen peroxide and ammonia as an etchant for etching the adhesion layer 191. An etchant containing components can be used. Therefore, it is possible to suppress the occurrence of electrolytic corrosion due to the electrodes (the first electrode 60, the second electrode 80, etc.) by the etching solution for etching the adhesion layer 191, and to suppress the peeling of the electrode, the lead electrode 90, and the like. be able to.

  Incidentally, when nickel (Ni), chromium (Cr) or nickel chromium (NiCr) is used as the adhesion layer 191, it is necessary to use an acid such as cerium ammonium nitrate as an etchant. When it comes into contact with the electrode, there is a possibility that electrolytic corrosion occurs on the electrode, and peeling of the electrode and the lead electrode 90 occurs.

  In this embodiment, by using titanium tungsten (TiW) as the adhesion layer 191, it is possible to suppress the occurrence of electrolytic corrosion on the electrode by the etching solution when the adhesion layer 191 is wet-etched. Peeling can be suppressed. In this embodiment, titanium tungsten (TiW) is used as the adhesion layer 191, but the present invention is not particularly limited thereto. For example, even if titanium or tungsten is used alone as the adhesion layer 191, etching is performed. Since a material other than an acid can be used as the liquid, it is possible to suppress the occurrence of electrolytic corrosion on the electrode.

  Further, when an acid is used as an etching solution for wet etching the adhesion layer 191, the etching solution adheres to the piezoelectric layer 70 and damages the piezoelectric layer 70. In this embodiment, the adhesion layer By using titanium tungsten (TiW) as 191, an etching solution containing hydrogen peroxide water and an alkaline component such as ammonia can be used instead of an acid as an etching solution for etching the adhesion layer 191. Damage to the body layer 70 can be reduced. Therefore, it is possible to suppress the acid from damaging the crystallinity and the like of the piezoelectric layer 70 and to suppress problems such as a decrease in piezoelectric characteristics and a decrease in durability due to the damage of the piezoelectric layer 70.

  Furthermore, in this embodiment, since copper (Cu) is used as the conductive layer 192, the conductive layer 192 can be formed at a lower cost than when gold (Au) is used. Note that copper (Cu) has a lower electrical resistance than gold (Au). Therefore, the conductive layer 192 made of copper can be formed thinner than when gold (Au) is used. Thus, the piezoelectric layer 70 can be formed thinner than the gold conductive layer, and the individual lead electrodes 91 (lead electrodes 90) can be arranged at a high density.

  Further, at least a terminal portion of such a lead electrode 90 (wiring layer) is an electroless plating comprising a catalyst layer 193, a nickel layer 194 formed by electroless plating, a palladium layer 195, and a gold layer 196. Layers are stacked.

Here, the catalyst layer 193 functions as a catalyst (activator) for subsequent electroless plating. Such a catalyst layer 193 is obtained by forming a metal nucleus (catalyst layer 193) necessary for subsequent electroless plating deposition using a catalyst solution containing an ionized metal. In this embodiment, a palladium nucleus is formed using a catalyst solution containing palladium ions (Pd ²⁺ ) to form a catalyst layer 193 made of palladium.

  Examples of the method for forming the catalyst layer 193 made of palladium include a dip type and a spray type (spin type). The dip method is a method of immersing a substrate in a chemical bath, and examples thereof include a sensitizer-activator method, a catalyzer-accelerator method, and a catalyzing-reducing method.

In the sensitizer-activator method, for example, a substrate is immersed in a sensitizer solution that is a hydrochloric acid solution of tin chloride, and then immersed in an activator solution that is a hydrochloric acid solution of palladium chloride to form a palladium nucleus. In the catalyzer-accelerator method, the substrate is dipped in a catalyzer solution (a colloid solution containing Sn ²⁺ and Pd ²⁺ ) and then dipped in a hydrochloric acid solution to form palladium nuclei. In the catalytic-reduction method, the palladium complex is adsorbed by being immersed in a catalyst solution (ionic palladium complex), washed with water, and then immersed in a reducing solution to form palladium nuclei by reduction. Incidentally, the spray method is a method of spraying a chemical solution from a nozzle onto a substrate. As other methods, there is an ink jet method in which a chemical solution is ejected onto a substrate using an ink jet recording head. In this embodiment, the catalyst layer 193 containing palladium is formed by a dip-type sensitizer-activator method. In addition, since the formation of the catalyst layer 193 by the dip method can be batch-processed, there is an effect that the efficiency of the production process is high.

The nickel layer 194 is formed by electroless plating on the opposite side of the catalyst layer 193 from the lead electrode 90, and contains nickel (Ni) as a main component.
The palladium layer 195 is formed by electroless plating on the surface of the nickel layer 194 opposite to the catalyst layer 193, and contains palladium (Pd) as a main component. By providing the palladium layer 195, diffusion of Ni in the nickel layer 194 and Au in the gold layer 196 described later is prevented.
The gold layer 196 is formed on the opposite side of the palladium layer 195 from the nickel layer 194 by electroless plating, and contains gold (Au) as a main component.

  In the present embodiment, the electroless plating layer composed of the nickel layer 194, the palladium layer 195, and the gold layer 196 is not deposited in a region other than the region to be electrolessly plated. Here, the region other than the region where electroless plating is performed is a region where the electroless plating layer is not originally formed. Specifically, the wiring layer on the second electrode as shown in FIG. It refers to the region of the end side 90a, the upper surface 70a of the piezoelectric layer where no wiring layer is provided, and the upper surface 80a of the second electrode.

  Although details will be described later in this embodiment, a catalyst layer is provided over the lead electrode 90 (wiring layer) with a resist layer provided in advance in a region other than the region where electroless plating is performed and the resist layer is provided. 193 and an electroless plating layer composed of a nickel layer 194, a palladium layer 195, and a gold layer 196 are formed by electroless plating. During the electroless plating, regions other than the region to be electrolessly plated are completely covered with the resist layer 200, so that the electroless plating layer is prevented from being deposited in these regions, and the decrease in the displacement amount of the piezoelectric element 300 is suppressed. Is done.

  The electroless plating layer composed of the catalyst layer 193 and the nickel layer 194, the palladium layer 195, and the gold layer 196 is connected to at least the terminal portion to which the connection wiring 121 is connected, that is, the piezoelectric element 300 of the lead electrode 90. In this embodiment, the lead electrode 90 is formed over the entire surface as long as it is formed at the end opposite to the end. Thereby, it is not necessary to remove the electroless plating layer composed of the catalyst layer 193 other than the terminal portion and the nickel layer 194, the palladium layer 195, and the gold layer 196 by patterning, thereby reducing the patterning process and reducing the cost. can do.

  Further, by providing the gold layer 196 at least on the uppermost layer of the terminal portion of the lead electrode 90, when the connection wiring 121 is mounted on the lead electrode 90, the connection strength is improved and the separation of the connection wiring 121 is suppressed. Can do. That is, even if the connection wiring 121 is directly mounted on the copper (Cu) conductive layer 192, the adhesion force is weak and the connection wiring 121 may be peeled off. By providing the gold layer 196 as an upper layer, the connection strength between the gold layer 196 and the connection wiring 121 can be improved. The connection between the gold layer 196 and the connection wiring 121 is not limited to the wire bonding method, and for example, soldering or the like may be used.

  In addition, since the gold layer 196 can be formed relatively thin and can be selectively formed on the lead electrode 90 by electroless plating, the recovery rate of gold (Au) in the plating solution is improved. Cost can be reduced.

  As shown in FIGS. 1 and 3, 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 (individual lead electrode 91 and common lead electrode 92) connected to the first electrode 60 of each active part 310 is provided so as to be exposed in the through hole 33.

  A driving circuit 120 that functions as a signal processing unit is fixed on the protective substrate 30. As the drive circuit 120, for example, a circuit board, a semiconductor integrated circuit (IC), or the like can be used. The drive circuit 120 and the lead electrode 90 are electrically connected via a connection wiring 121 (external wiring in the present embodiment) made of a conductive wire such as a bonding wire having the through-hole 33 inserted therethrough. The external wiring is not limited to the connection wiring 121 made of a conductive wire. For example, a flexible printed circuit board (FPC) such as a chip on film (COF) or a tape carrier package (TCP) is connected to the lead electrode 90. It may be.

  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. 6 to 12 are cross-sectional views showing a method for manufacturing the ink jet recording head.

  First, as shown in FIG. 6A, 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 material of the elastic film 51 is not limited to silicon dioxide, and may be a silicon nitride film, a polysilicon film, an organic film (such as polyimide or parylene), or the like. The formation method of the elastic film 51 is not limited to thermal oxidation, and may be formed by a sputtering method, a CVD method, a spin coating method, or the like.

Next, as shown in FIG. 6B, an insulator film 52 made of zirconium oxide is formed on the elastic film 51. Of course, the insulator film 52 is not limited to zirconium oxide, and titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), magnesium oxide (MgO), lanthanum aluminate (LaAlO _3). ) Etc. may be used. Examples of a method for forming the insulator film 52 include a sputtering method, a CVD method, and a vapor deposition method. In the present embodiment, the diaphragm 50 is formed by the elastic film 51 and the insulator film 52, but only one of the elastic film 51 and the insulator film 52 may be provided as the diaphragm 50. Further, an adhesion layer for improving the adhesion of the first electrode 60 to the base may be provided on the vibration plate 50.

  Next, as shown in FIG. 6C, 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. Moreover, the 1st electrode 60 can be formed by sputtering method, PVD method (physical vapor deposition method), etc., for example.

Next, as shown in FIG. 7A, a crystal seed layer 61 made of titanium (Ti) is formed on the first electrode 60. By providing the crystal seed layer 61 on the first electrode 60 in this way, the piezoelectric layer 70 is formed when the piezoelectric layer 70 is formed on the first electrode 60 via the crystal seed layer 61 in a later step. Can be controlled to the (100) plane, and a piezoelectric layer 70 suitable as an electromechanical transducer can be obtained. The crystal seed layer 61 functions as a seed that promotes crystallization when the piezoelectric layer 70 is crystallized, and diffuses into the piezoelectric layer 70 after the piezoelectric layer 70 is fired. In the present embodiment, titanium (Ti) is used as the crystal seed layer 61. However, the crystal seed layer 61 is a crystal of the piezoelectric layer 70 when the piezoelectric layer 70 is formed in a later step. For example, titanium oxide (TiO ₂ ) may be used as the crystal seed layer 61, and materials other than titanium and titanium oxide, such as lanthanum nickel oxide, may be used. A thing (LNO) etc. can also be used. Of course, the crystal seed layer 61 may remain between the first electrode 60 and the piezoelectric layer 70. The crystal seed layer 61 may be a layer or an island.

  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. 7B, a piezoelectric precursor film 73 that is a PZT precursor film is formed on the crystal seed layer 61. 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 (crystal seed layer 61) is formed (application step). Next, the piezoelectric precursor film 73 is heated to a predetermined temperature and dried for a predetermined time (drying step). For example, in this embodiment, the piezoelectric precursor film 73 can be dried by holding at 170 to 180 ° C. for 3 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 3 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, as shown in FIG. 7C, the piezoelectric precursor film 73 is crystallized by being heated to a predetermined temperature and held for a predetermined time to form a 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.

  The crystal seed layer 61 formed on the first electrode 60 diffuses into the piezoelectric film 74. Of course, the crystal seed layer 61 may remain as titanium between the first electrode 60 and the piezoelectric film 74, or may remain as titanium oxide.

  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, as shown in FIG. 7D, 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 their side surfaces. Are simultaneously patterned so as to be inclined. The patterning of the first electrode 60 and the first piezoelectric film 74 can be performed by dry etching such as 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. .

  Next, as shown in FIG. 8A, after patterning the first piezoelectric film 74 and the first electrode 60, the side surface of the first electrode 60 and the first layer on the insulator film 52 are formed. An intermediate crystal seed layer 62 is formed across the side surface of the piezoelectric film 74 and the piezoelectric film 74. As in the crystal seed layer 61, the intermediate crystal seed layer 62 can be made of titanium, lanthanum nickel oxide, or the like. Further, like the crystal seed layer 61, the intermediate crystal seed layer 62 may be layered or island-shaped.

  Next, as shown in FIG. 8B, a piezoelectric body comprising a plurality of layers of piezoelectric films 74 by repeating the piezoelectric film forming process including the coating process, the drying process, the degreasing process and the firing process described above a plurality of times. Layer 70 is formed.

  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. Since the intermediate crystal seed layer 62 is formed in the region where the second and subsequent piezoelectric films 74 are formed, the intermediate crystal seed layer 62 allows the second and subsequent piezoelectric films 74 to be preferentially oriented. It can be controlled to the (100) plane and can be formed with a fine particle size. The intermediate crystal seed layer 62 functions as a seed that promotes crystallization when the piezoelectric layer 70 is crystallized. Even if the piezoelectric layer 70 is baked, all of the intermediate crystal seed layer 62 diffuses into the piezoelectric layer 70. Moreover, a part may remain as it is or as an oxide.

  Next, as shown in FIG. 8C, the first layer 81 of 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.

  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.

  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 A second layer 82 made of, for example, iridium (Ir) is formed and patterned on the patterned side surface of the layer 70, the insulator film 52, the first electrode 60, and the like to form the second electrode 80. Form. In the patterning of the second layer 82, a part of the first layer 81 is simultaneously patterned to form the removal portion 83. As a result, the active portion 310 of the piezoelectric element 300 is defined, and the individual lead electrode 91 and the common lead electrode 92 are formed.

  Next, as shown in FIG. 9 (c), 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 second electrode 80, the piezoelectric material For example, an adhesion layer 191 made of titanium tungsten (TiW) and a conductive layer 192 made of copper (Cu) are formed on the patterned side surface of the layer 70, the insulator film 52, the first electrode 60, and the like. By forming the stacked layers, lead electrodes 90 that are wiring layers are formed. Note that a method for forming the adhesion layer 191 and the conductive layer 192 is not particularly limited, and examples thereof include a sputtering method and an electroless plating method. However, when the adhesion layer 191 and the conductive layer 192 are formed by the electroless plating method, it takes time until the desired thickness is reached. Therefore, it is necessary to form by a sputtering method that can be formed relatively thick in a short time. preferable.

  Next, as shown in FIG. 9D, the conductive layer 192 is patterned into a predetermined shape. That is, a mask having a predetermined shape is formed on the conductive layer 192 (not shown), and the conductive layer 192 is etched through the mask for patterning. Note that the conductive layer 192 may be etched by wet etching or dry etching.

  Next, as shown in FIG. 9E, the adhesion layer 191 is patterned by wet etching. In this embodiment, using the conductive layer 192 as a mask, the adhesion layer 191 is wet-etched with an etchant containing hydrogen peroxide and an alkali component. Thereby, the individual lead electrode 91 and the common lead electrode 92 are formed, and the piezoelectric layer 70 and a part of the second electrode 80 are exposed.

  At this time, since the etching solution for etching the adhesion layer 191 is a solution containing hydrogen peroxide, ammonia overwater, and an alkali component, electrolytic corrosion occurs in the electrodes (the first electrode 60 and the second electrode 80). Can be suppressed.

  In the present embodiment, since titanium tungsten (TiW) is used as the adhesion layer 191, etching is performed using an etching solution containing hydrogen peroxide, ammonia overwater, and an alkali component without using an acid as the etching solution. It is possible to suppress the occurrence of electrolytic corrosion on the electrode and to suppress the peeling of the electrode and the lead electrode 90.

  Further, since copper (Cu) is used for the conductive layer 192, the conductive layer 192 can be formed at a lower cost than in the case where gold (Au) is used. Note that copper (Cu) has a lower electrical resistance than gold (Au). Therefore, the conductive layer 192 made of copper can be formed thinner than when gold (Au) is used. Since the conductive layer 192 can be thinly formed as described above, the displacement characteristic of the piezoelectric element 300 can be improved by suppressing the conductive layer 192 from inhibiting the displacement of the piezoelectric element 300 (active portion 310). At the same time, the piezoelectric layer 70 can be formed thinner than the gold conductive layer, and the active portions 310 can be arranged at a high density.

  Next, as shown in FIG. 10A, a resist layer 200 is formed on a part of the piezoelectric layer 70 and the second electrode 80 exposed by patterning the adhesion layer 191, and electroless plating is performed. The area to be exposed is exposed. Here, the region to be electrolessly plated is a region where an electroless plating layer is formed by electroless plating on the patterned lead electrode 90 (wiring layer) via the catalyst layer 193, that is, a nickel layer 194, This refers to a region where the palladium layer 195 and the gold layer 196 are formed. A catalyst layer 193 made of palladium is formed on the electroless plating region using a catalyst solution containing palladium ions.

Next, as shown in FIG. 10B, a nickel layer 194 made of nickel (Ni) is formed on the catalyst layer 193. The nickel layer 194 can be selectively formed only on the conductive layer 192 by electroless plating using palladium ions (Pd ²⁺ ) in the catalyst layer 193 as a catalyst.

  Next, as shown in FIG. 10C, a palladium layer 195 made of palladium (Pd) is formed on the nickel layer 194. The palladium layer 195 can be selectively formed only on the nickel layer 194 by electroless plating.

  Next, as shown in FIG. 11A, a gold layer 196 made of gold (Au) is formed on the palladium layer 195. The gold layer 196 can be selectively formed only on the palladium layer 195 by electroless plating.

  Finally, as shown in FIG. 11B, the resist layer 200 is removed. As a result, an electroless plating layer composed of the catalyst layer 193 and the nickel layer 194, the palladium layer 195, and the gold layer 196 is formed on the lead electrode 90, which is a wiring layer.

  In the present embodiment, such an electroless plating layer is formed by providing a region other than the region to be electrolessly plated, that is, the end portion 90a of the wiring layer exposed by patterning of the adhesion layer 191 and the wiring layer. This is performed by providing the resist layer 200 in advance in the regions of the upper surface 70a of the piezoelectric layer not formed and the upper surface 80a of the second electrode. More specifically, the electroless plating layer first uses a catalyst solution containing palladium ions over the lead electrode 90 (wiring layer) while the resist layer 200 is provided in a region other than the region to be electrolessly plated. The catalyst layer 193 is formed, and then the nickel layer 194, the palladium layer 195, and the gold layer 196 are sequentially laminated by electroless plating, and finally the resist layer 200 is removed.

  Here, the palladium ion contained in the catalyst solution is a metal ion that originally adheres only to copper because of the relationship with the potential of copper contained in the conductive layer 192. However, since copper tends to cause migration, the copper migration moves the copper potential to the second electrode 80 and the palladium ion potential also moves to the second electrode 80. As a result, a palladium nucleus (catalyst layer 193) is deposited in a region other than the region to be electrolessly plated, and an electroless plating layer originally formed for the purpose of protecting the lead electrode 90 (wiring layer) is formed on the palladium nucleus. Precipitate. Such deposition of the electroless plating layer inhibits the deflection of the piezoelectric layer 70 and reduces the displacement of the piezoelectric element 300. In this embodiment, in order to prevent deposition of the electroless plating layer, the region other than the region to be electroless plated is completely covered with the resist layer 200 during the electroless plating. Thereby, the deposition of the electroless plating layer in a region other than the region where electroless plating is performed is prevented, and a decrease in the displacement of the piezoelectric element 300 is suppressed.

  Note that by selectively forming the gold layer 196 or the like on the lead electrode 90, only the necessary gold layer 196 is formed on the lead electrode 90, so that the cost can be reduced. That is, for example, when gold (Au) is formed over the entire surface of one surface of the flow path forming substrate wafer 110 and then patterned by etching, the recovery rate of gold removed by etching is poor and the cost is high. End up. On the other hand, when the gold layer 196 is formed by electroless plating, the gold layer 196 can be selectively formed only on the lead electrode 90, so there is no need to recover the gold removed by etching. The gold recovery rate can be improved because gold can be recovered from the electroless plating solution. Therefore, the cost can be reduced by forming the gold layer 196 by electroless plating.

  After that, 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 disposed 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.

  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.

(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 each of the embodiments described above, the catalyst layer 193 and the electroless plating layer including the nickel layer 194, the palladium layer 195, and the gold layer 196 are provided on the lead electrode 90. However, the present invention is not particularly limited thereto. For example, the palladium layer 195 may not be provided. That is, the catalyst layer 193, the nickel layer 194 and the gold layer 196 may be laminated on the lead electrode 90. That is, the gold layer 196 is provided above the nickel layer 194. Even when the gold layer 196 is provided immediately above the nickel layer 194, another member, for example, a palladium layer 195 is interposed therebetween. It also includes the state.

  In the above-described first embodiment, the configuration in which the piezoelectric layers 70 of the respective active units 310 are continuously provided has been illustrated, but of course, the piezoelectric layers 70 are provided independently for each active unit 310. May be.

  Furthermore, for example, in each of the above-described embodiments, the piezoelectric precursor film 73 is applied, dried and degreased, and then baked to form the piezoelectric film 74. However, the present invention is not particularly limited thereto. The step of applying, drying, and degreasing the piezoelectric precursor film 73 may be repeated a plurality of times, for example, twice, and then baked to form the piezoelectric film 74.

  The ink jet recording head I is mounted on an ink jet recording apparatus II as shown in FIG. 13, for example. 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. A carriage 3 on which the recording head units 1A and 1B are mounted is attached to the apparatus main body 4. The carriage shaft 5 is attached 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.

  The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and 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 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 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 embodiments, the ink jet recording head has been described as an example of the liquid ejecting head. However, the present invention is widely applied to all liquid ejecting heads, and ejects liquid other than ink. Of course, it can also be applied to the head. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

  Further, the piezoelectric element according to the present invention is not limited to the piezoelectric element used in the liquid ejecting head, and can be used in other devices. Other devices include, for example, an ultrasonic device such as an ultrasonic transmitter, an ultrasonic motor, a temperature-electric converter, a pressure-electric converter, a ferroelectric transistor, a piezoelectric transformer, and a filter for blocking harmful rays such as infrared rays. And filters such as an optical filter using a photonic crystal effect by quantum dot formation, an optical filter using optical interference of a thin film, and the like. The present invention can also be applied to a piezoelectric element used as a sensor and a piezoelectric element used as a ferroelectric memory. Examples of the sensor using the piezoelectric element include an infrared sensor, an ultrasonic sensor, a thermal sensor, a pressure sensor, a pyroelectric sensor, and a gyro sensor (angular velocity sensor).

  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 Recess, 80 Second electrode, 90 Lead electrode (wiring layer), 100 Manifold, 191 Adhesion layer, 192 Conductive layer, 193 Catalyst layer, 194 nickel layer, 195 palladium layer, 196 gold layer, 300 piezoelectric element, 310 active part

Claims (13)

A first electrode; a second electrode; a piezoelectric layer disposed between the first electrode and the second electrode; a wiring layer including copper provided on the second electrode; and the wiring layer A piezoelectric element provided with an electroless plating layer provided thereon via a catalyst layer,
The piezoelectric element, wherein the electroless plating layer is not provided on an end portion side of the wiring layer on the second electrode.   The piezoelectric element according to claim 1, wherein the catalyst layer is made of palladium formed from a catalyst solution containing palladium ions.   The electroless plating layer includes a nickel layer containing nickel formed by electroless plating and a gold layer containing gold formed by electroless plating above the nickel layer. 3. The piezoelectric element according to 1 or 2. The piezoelectric element according to claim 3 , further comprising a palladium layer formed by electroless plating between the nickel layer and the gold layer.   5. The piezoelectric element according to claim 1, wherein an adhesion layer containing at least one of titanium and tungsten is provided on the second electrode side of the wiring layer. The first electrode constitutes an individual electrode provided for each active part that is a substantial driving part of the piezoelectric element,
The piezoelectric element according to claim 1, wherein the second electrode constitutes a common electrode common to the plurality of active portions. A flow path forming substrate having a pressure generating chamber communicating with a nozzle opening for ejecting liquid;
The piezoelectric element according to any one of claims 1 to 6, provided on one side of the flow path forming substrate,
A liquid ejecting head comprising:   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 7.   An ultrasonic device comprising the piezoelectric element according to claim 1.   A filter comprising the piezoelectric element according to claim 1.   A sensor comprising the piezoelectric element according to claim 1. A first electrode; a second electrode; a piezoelectric layer provided between the first electrode and the second electrode; a wiring layer including copper provided on the second electrode; and the wiring layer A method of manufacturing a piezoelectric element comprising an electroless plating layer provided on a catalyst layer on the top,
Forming a conductive layer containing copper on the second electrode;
Patterning the conductive layer by etching to form the wiring layer;
A step of exposing a region to be electrolessly plated by providing a resist layer above the piezoelectric layer and the second electrode, and patterning;
Forming a catalyst layer made of palladium on the exposed electroless plating region using a catalyst solution containing palladium ions;
Forming a nickel layer containing nickel by electroless plating on the catalyst layer;
Forming a gold layer containing gold by electroless plating above the nickel layer;
And a step of removing the resist layer .   The method for manufacturing a piezoelectric element according to claim 12, further comprising a step of forming a palladium layer on the nickel layer by electroless plating after the step of forming the nickel layer.

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