JP2014192436A - Liquid ejection head, liquid ejection device, piezoelectric element, and actuator device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejection head, a liquid ejection device, a piezoelectric element, and an actuator device in which unevenness of a crystal grain of a piezoelectric body layer near a boundary between an electrode and a diaphragm is eliminated, abnormal growth of a crystal in the piezoelectric body layer is prevented, and destruction of the diaphragm and the piezoelectric element near a boundary between a piezoelectric body active part and a piezoelectric body nonactive part is prevented.SOLUTION: A liquid ejection head, which includes a piezoelectric element 300 including a piezoelectric body layer 70 and an electrode provided for the piezoelectric body layer, includes: a first electrode 60 including a first conductor layer 61 and a second conductor layer 62 provided on the first conductor layer, made of lanthanum nickel oxide, and serving also as an orientation control layer; a piezoelectric body layer provided on the first electrode; and a second electrode 80 provided on the piezoelectric body layer. The piezoelectric element includes: a first piezoelectric body active part 310 sandwiched between (i) the first conductor layer and the second conductor layer and (ii) the second electrode; and a second piezoelectric body active part 320 sandwiched between the second conductor layer and the second electrode.

Description

  The present invention relates to a piezoelectric element in which a piezoelectric layer and electrodes are provided on both sides thereof, an actuator device having the piezoelectric element, a liquid ejecting head having the actuator device, and a liquid ejecting apparatus.

  In a piezoelectric element used for an ink jet recording head known as a representative example of a liquid ejecting head, a technique for forming a piezoelectric layer on a titanium layer is known in order to improve the crystallinity of the piezoelectric layer. . For example, in Patent Document 1, a first piezoelectric layer is formed on a lower electrode via a titanium layer, and then the lower electrode is patterned together with the first piezoelectric layer to form a first piezoelectric layer. A method of manufacturing a piezoelectric element is disclosed in which a titanium layer is further formed on the layer and the diaphragm, and then the remaining piezoelectric layer is formed. Patent Document 2 discloses a piezoelectric element in which a lower electrode is patterned, a titanium layer is provided on the whole, and a piezoelectric layer is provided thereon.

However, when the orientation control of the piezoelectric layer is performed with such a titanium layer, in either case of Patent Documents 1 and 2, the crystal grains of the piezoelectric layer formed on the diaphragm are piezoelectric on the lower electrode. There is a problem that the crystal grains are likely to be larger than the crystal grains of the body layer, the crystal grains are non-uniform, and abnormal growth such as small holes occurs at the patterning boundary of the lower electrode, both of which cause cracks. In the method of manufacturing a piezoelectric element disclosed in Patent Document 1, the crystal of the piezoelectric layer is divided between the first layer and the second layer by the titanium layer formed on the first piezoelectric layer. It may be discontinuous and may affect the crystallinity of the piezoelectric layer.
A technique using lanthanum nickel oxide (LNO) instead of a titanium layer as an orientation control layer is also known (for example, Patent Documents 3 and 4).

  However, in Patent Documents 3 and 4, LNO as an orientation control layer is provided on the upper layer of the metal layer, and both are patterned together, and the crystal grains of the piezoelectric layer on the electrode and on the diaphragm are not uniform. There is a problem of becoming.

JP 2002-83937 A Japanese Patent Laid-Open No. 2003-282843 Japanese Patent Laid-Open No. 2004-066600 JP 2009-234022 A

In any case, the techniques of Patent Documents 1 to 4 do not solve the problem caused by the nonuniformity of crystal grains of the piezoelectric layer on the electrode and the diaphragm.
On the other hand, in the vicinity of the end of the pressure generating chamber, there is a boundary between a region where the displacement of the vibration plate is large and a region where the vibration plate is small. There is also a problem of where the boundary between the piezoelectric active part to which the voltage is applied and the piezoelectric inactive part to which no electric field is applied is arranged.

  Such a problem exists not only in the ink jet recording head, but of course in other liquid ejecting heads that eject droplets other than ink as well. The same applies to piezoelectric actuators.

  In view of such circumstances, the present invention eliminates the crystal grain non-uniformity and abnormal crystal growth in the vicinity of the boundary between the electrode and the diaphragm, and the piezoelectric active part and the piezoelectric non-active part. An object of the present invention is to provide a liquid ejecting head, a liquid ejecting apparatus, a piezoelectric element, and an actuator device that prevent the diaphragm and the piezoelectric element near the boundary of the substrate from being destroyed.

According to an embodiment of the present invention for solving the above-described problem, there is provided a liquid ejecting head including a piezoelectric element including a piezoelectric layer and an electrode provided on the piezoelectric layer, the first conductive layer and the first conductive layer. A first electrode comprising a second conductor layer made of lanthanum nickel oxide and also serving as an orientation control layer; a piezoelectric layer provided on the first electrode; and the piezoelectric layer A first electrode active portion sandwiched between the first conductor layer, the second conductor layer, and the second electrode; and a second electrode provided on the second electrode; The liquid ejecting head includes a second piezoelectric active part sandwiched between two conductor layers and the second electrode.
In this aspect, the crystal layer non-uniformity and abnormal crystal growth in the vicinity of the boundary between the first electrode and the vibration plate are eliminated, and the vicinity of the boundary between the piezoelectric active portion and the piezoelectric inactive portion is eliminated. Breakage of the diaphragm and the piezoelectric element can be prevented.

  Here, it is preferable that the patterning shape of the piezoelectric layer substantially matches the patterning shape of the second conductor layer. Thereby, there is no portion where the second conductor layer is exposed.

  In addition, the plurality of piezoelectric elements are provided for each pressure generation chamber on one surface side of a flow path forming substrate in which a plurality of pressure generation chambers communicating with a nozzle opening for ejecting a liquid are arranged in parallel, and the first conductor layer Is provided so as not to cover the region facing the end of the pressure generating chamber in the second direction continuously across the first direction, which is the parallel direction of the pressure generating chambers, and in the second direction intersecting the first direction. The second conductor layer and the piezoelectric layer are provided for each pressure generating chamber individually and so as to cover a region facing the end portion of the pressure generating chamber in the second direction. preferable. As a result, at the second direction end portion of the pressure generating chamber, the second piezoelectric active portion continuous to the outside of the first piezoelectric active portion extends to the outside of the pressure generating chamber, and the vibration plate and the piezoelectric element are destroyed. Is prevented.

  The piezoelectric layer is preferably made of lead zirconate titanate, does not contain orientation controlling titanium, and has a crystal structure in which crystals are not divided in the thickness direction. Thus, by eliminating titanium such as seed titanium and intermediate titanium, it has a crystal structure in which crystals are not divided in the thickness direction.

Another aspect is a liquid ejecting apparatus including the liquid ejecting head according to the above aspect.
In this aspect, the crystal layer non-uniformity and abnormal crystal growth in the vicinity of the boundary between the first electrode and the vibration plate are eliminated, and the vicinity of the boundary between the piezoelectric active portion and the piezoelectric inactive portion is eliminated. A liquid ejecting apparatus that prevents the vibration plate and the piezoelectric element from being destroyed can be realized.

In another aspect, the first electrode includes a first conductor layer, a second electrode provided on the conductor layer and made of lanthanum nickel oxide and serving as an orientation control layer, and the second electrode. A piezoelectric layer provided on the common electrode; and a second electrode provided on the piezoelectric layer, wherein the piezoelectric element includes the first conductor layer, the second conductor layer, and the second electrode. A piezoelectric element comprising: a first piezoelectric active part sandwiched between electrodes; and a second piezoelectric active part sandwiched between the second conductor layer and the second electrode.
In this aspect, the crystal layer non-uniformity and abnormal crystal growth in the vicinity of the boundary between the first electrode and the vibration plate are eliminated, and the vicinity of the boundary between the piezoelectric active portion and the piezoelectric inactive portion is eliminated. A piezoelectric element that prevents the diaphragm and the piezoelectric element from being destroyed can be realized.

According to another aspect, there is provided an actuator device comprising the above-described piezoelectric element that can be displaced.
In this aspect, the crystal layer non-uniformity and abnormal crystal growth in the vicinity of the boundary between the first electrode and the vibration plate are eliminated, and the vicinity of the boundary between the piezoelectric active portion and the piezoelectric inactive portion is eliminated. An actuator device that prevents the vibration plate and the piezoelectric element from being destroyed can be realized.

FIG. 2 is an exploded perspective view illustrating a schematic configuration of the recording head according to the first embodiment. 2A and 2B are a plan view and a cross-sectional view of the recording head according to the first embodiment. FIG. 3 is an enlarged cross-sectional view of a main part of the recording head according to the first embodiment. FIG. 3 is an enlarged plan view of a main part of the recording head according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. 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. 1 is a diagram illustrating a schematic configuration of a recording apparatus according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail based on embodiments.
FIG. 1 is an exploded perspective view showing a schematic configuration of an ink jet recording head which is an example of a liquid ejecting head according to Embodiment 1 of the present invention. FIG. 2 is a plan view of a flow path forming substrate and the ink jet recording head. 3 is a sectional view in the longitudinal direction of the pressure generating chamber of FIG. 3. FIG. 3 is an enlarged view of a main part of the cross section taken along the line AA 'of FIG. 2, and FIG.

As shown in the figure, the flow path forming substrate 10 of the present embodiment is made of a silicon single crystal substrate, and an elastic film 50 made of silicon dioxide is formed on one surface thereof.
On the flow path forming substrate 10, a plurality of pressure generating chambers 12 are arranged side by side in a first direction which is the short direction. A communication portion 13 is formed in the longitudinal direction of the pressure generation chamber 12 of the flow path forming substrate 10, that is, in a region outside the second direction orthogonal to the first direction, and the communication portion 13 and each pressure generation chamber 12 Are communicated via an ink supply path 14 and a communication path 15 provided for each pressure generating chamber 12. The communication part 13 communicates with a manifold part 31 of a protective substrate, which will be described later, and constitutes a part of a manifold that becomes a common ink chamber for each pressure generating chamber 12. The ink supply path 14 is formed with a narrower width than the pressure generation chamber 12, and maintains a constant flow path resistance of ink flowing into the pressure generation chamber 12 from the communication portion 13. In this embodiment, the ink supply path 14 is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path. In the present embodiment, the flow path forming substrate 10 is provided with a liquid flow path including the pressure generation chamber 12, the communication portion 13, the ink supply path 14, and the communication path 15.

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

  On the other hand, the elastic film 50 is formed on the side opposite to the opening surface of the flow path forming substrate 10 as described above. On the elastic film 50, for example, zirconium oxide having a thickness of about 400 nm or the like. An insulator film 55 made of is formed. On the insulator film 55, an adhesion layer 56 made of an oxide such as titanium or zirconium is provided for improving the adhesion between the first electrode 60 such as the elastic film 50 and the like.

  Further, on the adhesion layer 56, a first electrode 60, a piezoelectric layer 70 which is a thin film having a thickness of 3 μm or less, preferably 0.3 to 1.5 μm, and a second electrode 80 are laminated. Thus, a piezoelectric element 300 is configured as pressure generating means for causing a pressure change in the pressure generating chamber 12. Here, the piezoelectric element 300 refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In addition, here, the piezoelectric element 300 that is displaceably provided on the substrate (the flow path forming substrate 10) is referred to as an actuator device. In the above-described example, the elastic film 50, the insulator film 55, the adhesion layer 56, and the first electrode 60 function as a vibration plate. However, the present invention is not limited to this. For example, the elastic film 50 or the insulator The film 55 and the adhesion layer 56 may not be provided. Further, the piezoelectric element 300 itself may substantially serve as a diaphragm.

  The first electrode 60 includes a first conductor layer 61 made of a conductive material, for example, platinum, iridium, iridium oxide or a laminated structure thereof, or a conductive oxide such as lanthanum nickel oxide, The second conductor layer 62 also serves as an orientation control layer made of lanthanum nickel oxide (LNO) and having a perovskite structure.

The second conductor layer 62 has a crystal orientation plane that is preferentially oriented to the (100) plane in a pseudo-cubic display, and is an orientation control layer that preferentially orients the piezoelectric layer 70 laminated thereon to (100). Function. In the present invention, “crystals are preferentially oriented in the (100) plane” means that all crystals are oriented in the (100) plane and most crystals (for example, 90% or more) are ( 100) plane is preferentially oriented. Moreover, since the 2nd conductor layer 62 comprises electroconductivity, it is preferable to set it as the thickness of 4 nm or more, Preferably it is 10 nm or more. Moreover, it is preferable to set it as thickness of 20 nm or less from the surface of ensuring the displacement of a piezoelectric element.
Further, since the second conductor layer 62 has a lead diffusion function when the piezoelectric layer 70 contains lead, it is not necessary to use platinum having the lead diffusion function in the first conductor layer 61 as well.

The piezoelectric layer 70 is made of a piezoelectric material of the oxide having a polarization structure formed on the first electrode 60, for example, may consist of a perovskite oxide represented by the general formula ABO _3, A is Pb B can contain at least one of zirconium and titanium. The B may further contain niobium, for example. Specifically, as the piezoelectric layer 70, for example, lead zirconate titanate (Pb (Zr, Ti) O ₃ : PZT), lead zirconate titanate niobate containing silicon (Pb (Zr, Ti, Nb) ) O ₃ : PZTNS) or the like can be used.

Further, the piezoelectric layer 70 is a lead-free piezoelectric material that does not contain lead, for example, a composite oxide having a perovskite structure containing bismuth ferrate or bismuth ferrate manganate, barium titanate or potassium bismuth titanate, or the like. It is good.
The second electrode 80 may be any material that exhibits metal conduction, and may be made of, for example, platinum, iridium, iridium oxide, or a laminated structure thereof.

  Here, as shown in FIG. 4 in which the main part of FIG. 2A is enlarged, the first conductor layer 61 and the second conductor layer 62 of the first electrode 60 have different patterning shapes. The first conductor layer 61 is continuously provided across the juxtaposed direction (first direction) of the pressure generating chambers 12, but at the end in the second direction orthogonal to the juxtaposed direction of the pressure generating chambers 12. It is not provided in the opposing region. On the other hand, the second conductor layer 62 has basically the same patterning shape as the second electrode 80 and the piezoelectric layer 70, and the pressure generating chamber 12 is arranged in the direction in which the pressure generating chambers 12 are arranged side by side (first direction). Is patterned with a dimension slightly smaller than the short dimension (dimension in the first direction) of the pressure generation chamber 12 in the region facing the first and second ends of the first conductor layer 61 in the second direction (longitudinal direction) of the pressure generation chamber 12. It extends beyond the portion to a region facing the outside of the pressure generation chamber 12. Accordingly, the piezoelectric element 300 includes a first piezoelectric active part including the first conductor layer 61, the second conductor layer 62, the piezoelectric layer 70, and the second electrode 80 in the center region in the second direction of the pressure generation chamber 12. 310 and a second piezoelectric active part 320 including a second conductor layer 62, a piezoelectric layer 70, and a second electrode 80, extending outward in the second direction of the first piezoelectric active part 310. It has.

  Here, the first piezoelectric active part 310 includes the first electrode 60 composed of the first conductor layer 61 and the second conductor layer 62, whereas the second piezoelectric active part 320 has the first conductive part 320. Since the first electrode 60 including only the second conductor layer 62 without the body layer 61 is provided, the electric field applied is relatively smaller than that of the first piezoelectric active part 310, and the piezoelectric strain is reduced. Becomes smaller. That is, in the region facing the vicinity of the end of the pressure generation chamber 12, the first conductor layer 61 does not exist, and thus the diaphragm is easily displaced, but the piezoelectric distortion is relatively greater than that of the first piezoelectric active portion 310. Since the small second piezoelectric active part 320 is provided and the second piezoelectric active part 320 extends to a region facing the outside of the pressure generating chamber 12, the vibration plate and the piezoelectric element 300 are secured while ensuring displacement. There is an effect that can prevent the destruction of. Incidentally, if the first piezoelectric active part 310 is extended to a region facing the outside of the pressure generating chamber 12, the stress at the boundary between the first piezoelectric active part 310 and the outer piezoelectric inactive part is increased. The diaphragm is not opened due to deformation of the diaphragm, and there is a possibility that destruction such as burnout or cracks due to stress concentration occurs at this boundary. In this embodiment, since the second piezoelectric active part 320 having a small piezoelectric strain is provided in the non-flexible part near the boundary where the diaphragm is difficult to deform, the stress concentration at the boundary with the non-piezoelectric active part is reduced. And the destruction can be suppressed.

  The piezoelectric element 300 is covered with a protective film 200 made of an insulating material having moisture resistance. In the present embodiment, the protective film 200 covers the side surface of the piezoelectric layer 70, the side surface of the second electrode 80, and the peripheral edge of the upper surface, and is continuously provided across the plurality of piezoelectric elements 300. That is, the main part, which is a substantially central region on the upper surface of the second electrode 80, is not provided with the protective film 200, but is provided with the opening 201 that opens the main part of the upper surface of the second electrode 80.

  The opening 201 penetrates the protective film 200 in the thickness direction and opens in a rectangular shape along the longitudinal direction of the piezoelectric element 300. For example, the protective film 200 extends over the entire surface of the flow path forming substrate 10. After forming the film, it can be formed by selective patterning.

By covering the piezoelectric element 300 with the protective film 200 in this way, it is possible to prevent damage due to leakage on the side surface of the piezoelectric element 300 due to moisture in the atmosphere. Here, the material of the protective film 200 may be any material having moisture resistance. For example, inorganic insulation such as silicon oxide (SiOx), tantalum oxide (TaO _x ), and aluminum oxide (AlO _x ) is used. A material or an organic insulating material such as polyimide (PI) can be used.

In addition, by providing the opening 201 in the protective film 200, it is possible to satisfactorily maintain the ink ejection characteristics without hindering the displacement of the piezoelectric element 300 (piezoelectric active portion).
The protective film 200 may be provided so as to cover at least the surface of the piezoelectric layer 70 of the piezoelectric element 300. A protective film is provided for each piezoelectric element 300 and is discontinuous across the plurality of piezoelectric elements 300. You may do it.

  On the protective film 200, for example, a lead electrode 90 made of gold (Au) or the like is provided. The lead electrode 90 has one end connected to the upper electrode film 80 through a communication hole 202 provided in the protective film 200 and the other end extended to the ink supply path 14 side of the flow path forming substrate 10. The extended tip portion is connected to a drive circuit 120 that drives a piezoelectric element 300 described later via a connection wiring 121.

  Further, on the flow path forming substrate 10 on which the piezoelectric element 300 is formed, a protective substrate 30 provided with a manifold portion 31 in a region facing the communication portion 13 is bonded via an adhesive 35. As described above, the manifold portion 31 communicates with the communication portion 13 of the flow path forming substrate 10 and constitutes the reservoir 100 serving as a common liquid chamber for the pressure generation chambers 12.

  Further, the protective substrate 30 is provided with a piezoelectric element holding portion 32 having a space that does not hinder the movement of the piezoelectric element 300 in a region facing the piezoelectric element 300. In addition, the piezoelectric element holding part 32 should just have a space of the grade which does not inhibit the motion of the piezoelectric element 300, and the said space may be sealed or may not be sealed.

  Further, a through hole 33 that penetrates the protective substrate 30 in the thickness direction is provided in a region between the piezoelectric element holding portion 32 and the manifold portion 31 of the protective substrate 30, and the lower electrode film 60 is provided in the through hole 33. And the tip of the lead electrode 90 are exposed.

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

  As the protective substrate 30, it is preferable to use a material substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10, for example, glass or ceramic material. It formed using the crystal substrate.

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

  In such an ink jet recording head of this embodiment, after taking ink from an external ink supply means (not shown) and filling the interior from the reservoir 100 to the nozzle opening 21, according to the recording signal from the drive circuit 120, Applying a voltage between each of the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generation chamber 12 to bend and deform the elastic film 50, the insulator film 55, the lower electrode film 60, and the piezoelectric layer 70. As a result, the pressure in each pressure generating chamber 12 increases and ink droplets are ejected from the nozzle openings 21.

  Hereinafter, a method for manufacturing such an ink jet recording head will be described with reference to FIGS. 5 to 7, 9, and 10 are cross-sectional views in the longitudinal direction of the pressure generating chamber showing the method of manufacturing the ink jet recording head that is an example of the liquid ejecting head according to the first embodiment of the invention. FIG. 8 is a cross-sectional view in the lateral direction.

First, as shown in FIG. 5A, a flow path forming substrate wafer 110, which is a silicon wafer on which a plurality of flow path forming substrates 10 are integrally formed, is thermally oxidized in a diffusion furnace at about 1100 ° C. A silicon dioxide film 51 constituting the elastic film 50 is formed on the surface. Of course, the material of the elastic film 50 is not limited to silicon dioxide, but may be a silicon nitride film, a polysilicon film, an organic film (such as polyimide or parylene), or the like. The method for forming the elastic film 50 is not limited to thermal oxidation, and may be formed by sputtering, CVD, spin coating, or the like.
Next, as shown in FIG. 5B, an insulator film 55 made of zirconium oxide is formed on the elastic film 50 (silicon dioxide film 51). Specifically, after forming a zirconium (Zr) layer on the elastic film 50 (silicon dioxide film 51) by, for example, sputtering, the zirconium layer is thermally oxidized in a diffusion furnace at 500 to 1200 ° C., for example. Thus, the insulator film 55 made of zirconium oxide (ZrO ₂ ) is formed. Note that the insulator film 55 is not limited to zirconium oxide, and is titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), magnesium oxide (MgO), lanthanum aluminate (LaAlO _3). ) Etc. may be used. Examples of the method for forming the insulator film 55 include a sputtering method, a CVD method, and a vapor deposition method.

  Next, as shown in FIG. 5C, a non-illustrated adhesion layer such as titanium or zirconium and a first conductor layer 61 made of, for example, platinum or iridium are laminated on the insulator film 55, Pattern into a shape (see FIG. 4).

  Next, as shown in FIG. 6 (a), the second conductor made of lanthanum nickel oxide (LNO) as shown in FIG. 6 (b) so as to cover the patterned first conductor layer 61. The layer 62 is laminated on the entire surface. The second conductor layer 62 can be formed by a sputtering method or a liquid phase method.

  Subsequently, as shown in FIG. 6C, the piezoelectric layer 70 is laminated on the second conductor layer 62. The method for manufacturing the piezoelectric layer 70 is not particularly limited. For example, a solution obtained by dissolving and dispersing an organometallic compound in a solvent is applied and dried, and further fired at a high temperature to obtain the piezoelectric layer 70 made of a metal oxide. The piezoelectric layer 70 can be formed using a chemical solution method such as a MOD (Metal-Organic Decomposition) method or a sol-gel method. The manufacturing method of the piezoelectric layer 70 is not limited to the MOD method or the sol-gel method. For example, the laser ablation method, the sputtering method, the pulse laser deposition method (PLD method), the CVD method, the aerosol deposition method. Etc.

  A specific procedure for forming the piezoelectric layer 70 will be described by taking the case of PZT as an example. That is, as shown in FIG. 6C, a sol (solution) containing titanium (Ti), zirconium (Zr) and lead (Pb) on the flow path forming substrate 10 on which the second conductor layer 62 is formed on the entire surface. ) Is applied (application process). Next, the piezoelectric precursor film 71 is heated to a predetermined temperature and dried for a predetermined time (drying step).

Next, the dried piezoelectric precursor film 71 is degreased by heating it to a predetermined temperature and holding it for a predetermined time (degreasing step). In addition, degreasing said here is separating the organic component contained in the piezoelectric precursor film 71 as, for example, NO ₂ , CO ₂ , H ₂ O or the like. Next, the piezoelectric precursor film 71 is crystallized by being heated to a predetermined temperature and held for a predetermined time, thereby forming the piezoelectric film 72 (firing step).

  A piezoelectric film 70 having a predetermined film thickness is formed by repeating the piezoelectric film forming process including the coating process, the drying process, the degreasing process, and the baking process a plurality of times. Here, the step of firing the piezoelectric precursor film 71 may be performed simultaneously for every two to four layers of the piezoelectric precursor film 71.

  As described above, the piezoelectric layer 70 of the present embodiment excludes seed titanium for orientation control based on the prior art, so-called intermediate titanium, and the like, and the LNO provided on the entire surface after the first conductor layer 61 is patterned. The second conductor layer 62 is continuously provided from the first layer to the uppermost layer, is preferentially oriented in the (100) plane, has no crystal division in the thickness direction, and has crystal grains. The crystal structure has no non-uniformity or abnormal growth.

Next, as shown in FIGS. 7A and 8A, the second electrode 80 made of, for example, iridium (Ir) is formed over the entire piezoelectric layer 70.
Next, as shown in FIGS. 7B and 8B, the piezoelectric layer 300 and the second electrode 80 are patterned in regions facing the pressure generation chambers 12 to form the piezoelectric element 300. Examples of the patterning of the piezoelectric layer 70 and the upper electrode film 80 include dry etching such as reactive ion etching and ion milling, or wet etching. In the case of dry etching, the second conductor layer 62 made of LNO functions as an etching stop layer.

Next, as shown in FIGS. 7C and 8C, the second conductor layer 62 in the region where the piezoelectric layer 70 second electrode 80 does not exist is removed by wet etching.
Next, as shown in FIGS. 7D and 8D, a protective film 200 is formed over the entire surface of the flow path forming substrate wafer 110, and then the protective film 200 is patterned into a predetermined shape. The opening 201 and the communication hole 202 are formed.

  Next, as shown in FIG. 9A, lead electrodes 90 are formed. Specifically, the lead electrode 90 made of, for example, gold (Au) or the like is formed over the entire surface of the flow path forming substrate wafer 110, and then, for example, is passed through a mask pattern (not shown) made of a resist or the like. Each piezoelectric element 300 is formed by patterning.

Next, as shown in FIG. 9B, a protective substrate wafer 130 that is a silicon wafer and serves as a plurality of protective substrates 30 is bonded to the piezoelectric element 300 side of the flow path forming substrate wafer 110.
Next, as shown in FIG. 9C, the flow path forming substrate wafer 110 is thinned to a predetermined thickness.

  Next, as shown in FIG. 10A, a mask film 52 is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, as shown in FIG. 10B, the flow path forming substrate wafer 110 is anisotropically etched (wet etching) using an alkaline solution such as KOH through the mask film 52, thereby forming the piezoelectric element 300. Corresponding pressure generating chambers 12, communication portions 13, ink supply passages 14, communication passages 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.

Example 1
An ink jet recording head having the same structure as described above and having a second conductor layer 62 made of LNO and having a thickness of 4 nm was manufactured.
With respect to such a piezoelectric element, the crystal structure of the piezoelectric layer at the patterning boundary of the first conductor layer 61 in the longitudinal section is observed with a scanning electron microscope (SEM), and the second conductor without the first conductor layer 61 being present. The crystal particles of the piezoelectric layer 70 formed on the layer 62 are compared with the crystal particles of the piezoelectric layer 70 in the region where the first conductor layer 61 and the second conductor layer 62 exist. It was observed whether large grains were present in the region where the body layer 61 was not present. In addition, the presence or absence of abnormal crystal growth such as small holes in the piezoelectric layer 70 at the patterning end of the first conductor layer 61 was also observed.

  Furthermore, the rate of occurrence of cracks when driven at 60 V for 25 minutes and the amount of displacement when driven at 25 V were measured. Further, X-ray diffraction measurement (XRD) (2θ / θ) with an X-ray diffractometer was performed to obtain the (100) plane orientation ratio of the piezoelectric layer.

The crack occurrence rate was determined by measuring the electric capacity and leakage current value of the piezoelectric element, and calculating the number of abnormal elements / total number of measured elements.
The amount of displacement was measured using a heterodyne laser displacement meter.

Moreover, the orientation rate was calculated | required with the following formula | equation.
(100) plane orientation ratio (%) = [diffraction peak intensity of (100) plane] / [sum of all diffraction peak intensities caused by crystals] × 100
The results are shown in Table 1.

(Example 2)
An ink jet recording head was produced in the same manner as in Example 1 except that the thickness of the second conductor layer 62 made of LNO was set to 12 nm, and the same test was performed.

(Example 3)
An ink jet recording head was produced in the same manner as in Example 1 except that the thickness of the second conductor layer 62 made of LNO was 20 nm, and the same test was performed.

Example 4
An ink jet recording head was produced in the same manner as in Example 1 except that the thickness of the second conductor layer 62 made of LNO was changed to 30 nm, and the same test was performed.

(Comparative Example 1)
An ink jet recording head was produced in the same manner as in Example 1 except that the thickness of the second conductor layer 62 made of LNO was 2 nm, and the same test was performed. Note that 2 nm of LNO diffused when the piezoelectric layer 70 was formed, and did not exist as a conductor layer.

(Comparative Example 2)
An ink jet recording head was prepared in the same manner as in Example 1 except that a titanium layer having a thickness of 4 nm was used instead of the second conductor layer 62 made of LNO, and the same test was performed. The 4 nm titanium layer diffused when the piezoelectric layer 70 was formed, and did not exist as a conductor layer.

(Comparative Example 3)
After forming the first layer of the piezoelectric layer on the first electrode via the titanium layer having a thickness of 4 nm as described in Patent Document 1, without providing the second conductor layer 62 made of LNO, The first electrode is patterned together with the first piezoelectric layer, a titanium layer having a thickness of 4 nm is further formed on the first piezoelectric layer and the vibration plate, and then the remaining piezoelectric layers are formed. An ink jet head similar to that in Example 1 was prepared and tested in the same manner.

(Comparative Example 4)
An ink jet recording head was produced in the same manner as in Comparative Example 3 except that LNO having a thickness of 2 nm was used instead of the titanium layer on the first electrode in Comparative Example 3, and the same test was performed.

  From the results shown in Table 1, in Examples 1 to 4, no large particles were observed in the piezoelectric layer 70 formed on the second conductor layer 62 without the first conductor layer 61, No abnormal growth of crystals such as small holes was observed in the piezoelectric layer 70 at the patterning end of the one conductor layer 61. Further, based on this result, and as described above, the first conductor layer 61 does not exist at the longitudinal end portion of the pressure generating chamber 12, and the second piezoelectric active portion 320 extends outside the first conductor layer 61. Therefore, the crack generation rate was remarkably low and the displacement amount was large.

On the other hand, even when LNO is used in the same manner as in Examples 1 to 4, in Comparative Example 1 where the thickness is small and does not exist as the second conductor layer 62, large grains and small holes are observed. Since the two piezoelectric active portions 320 were not formed, the crack generation rate was high.
In Comparative Example 2 in which a titanium layer was used instead of LNO, large particles were not observed, but small holes were observed and the crack generation rate was high.

Further, in Comparative Example 3 having a structure described in Patent Document 1, large grains are not observed, but a heterogeneous phase in which crystals are divided at the boundary with the first layer of the piezoelectric layer 70 is observed, and cracks are observed. The incidence was high.
Furthermore, in Comparative Example 4 using LNO instead of titanium of Patent Document 1, large grains and small holes were observed, and the occurrence rate of cracks was high.

(Other embodiments)
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this Embodiment, In the range which does not deviate from the main point of invention, it can change suitably.
The ink jet recording head described above constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and is mounted on the ink jet recording apparatus. FIG. 11 is a schematic view showing an example of the ink jet recording apparatus.

  In the ink jet recording apparatus shown in FIG. 11, the recording head units 1A and 1B having the ink jet recording head are provided with cartridges 2A and 2B constituting the ink supply means in a detachable manner, and the recording head units 1A and 1B are mounted. The carriage 3 is provided on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.

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

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

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

  DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 13 Communication part, 14 Ink supply path, 20 Nozzle plate, 21 Nozzle opening, 30 Protection board, 31 Manifold part, 32 Piezoelectric element holding part, 40 Compliance board, 60 1st electrode 61 First conductor layer, 62 Second conductor layer, 70 Piezoelectric layer, 71 Piezoelectric precursor film, 72 Piezoelectric film, 80 Second electrode, 90 Lead electrode, 100 Reservoir, 120 Drive circuit, 121 Connection Wiring, 300 piezoelectric element, 310 first piezoelectric active part, 320 second piezoelectric active part

Claims (7)

A liquid ejecting head including a piezoelectric element including a piezoelectric layer and an electrode provided on the piezoelectric layer,
A first electrode comprising a first conductor layer, a second conductor layer provided on the first conductor layer and made of lanthanum nickel oxide and serving also as an orientation control layer; and provided on the first electrode. A piezoelectric layer, and a second electrode provided on the piezoelectric layer,
The piezoelectric element is sandwiched between the first conductor layer, the second conductor layer, and the second electrode, the first piezoelectric active part sandwiched between the second electrode, and the second conductor layer and the second electrode. And a second piezoelectric active part.   The liquid jet head according to claim 1, wherein a patterning shape of the piezoelectric layer substantially matches a patterning shape of the second conductor layer.   A plurality of the piezoelectric elements are provided for each pressure generating chamber on one side of a flow path forming substrate in which a plurality of pressure generating chambers communicating with a nozzle opening for ejecting a liquid are arranged, and the first conductor layer is A region facing the end of the pressure generating chamber in the second direction continuously across the first direction, which is the parallel direction of the pressure generating chambers, and in the second direction intersecting with the first direction is provided so as not to cover, The second conductor layer and the piezoelectric layer are provided individually for each pressure generating chamber and so as to cover a region facing the end portion in the second direction of the pressure generating chamber. The liquid jet head according to claim 1.   The piezoelectric body layer is made of lead zirconate titanate, does not contain orientation controlling titanium, and has a crystal structure in which crystals are not divided in the thickness direction. The liquid jet head according to one item.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1. A first electrode comprising a first conductor layer and a second conductor layer provided on the conductor layer and made of lanthanum nickel oxide and serving also as an orientation control layer; and provided on the second common electrode. Comprising a piezoelectric layer and a second electrode provided on the piezoelectric layer;
The piezoelectric element is sandwiched between the first conductor layer, the second conductor layer, and the second electrode, the first piezoelectric active part sandwiched between the second electrode, and the second conductor layer and the second electrode. And a second piezoelectric active part.   An actuator device comprising the piezoelectric element according to claim 6 so as to be displaceable.

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