JP5024518B2 - Actuator device, liquid jet head, and image recording apparatus - Google Patents

Description

  The present invention relates to an actuator device having a piezoelectric element composed of a lower electrode, a piezoelectric layer made of a piezoelectric material, and an upper electrode on a vibration plate, and a liquid ejecting head.

  The piezoelectric element used in the actuator device is configured by sandwiching a piezoelectric layer made of a piezoelectric material exhibiting an electromechanical conversion function, for example, crystallized piezoelectric ceramics, between two electrodes, a lower electrode and an upper electrode. There is something. Such an actuator device is generally called a flexural vibration mode actuator device, and is used by being mounted on, for example, a liquid ejecting head or the like. As a typical example of the liquid ejecting head, for example, a part of the pressure generating chamber communicating with the nozzle opening for ejecting ink droplets is configured by a diaphragm, and the diaphragm is deformed by a piezoelectric element to There are ink jet recording heads that pressurize ink and eject ink droplets from nozzle openings. As an actuator device mounted on an ink jet recording head, for example, a piezoelectric film and an upper electrode film are formed over the entire surface by a film forming technique on a substrate provided with a lower electrode. In some cases, the upper electrode film is cut into a shape corresponding to the pressure generation chamber by a lithography method and a piezoelectric element is formed so as to be independent for each pressure generation chamber.

  Platinum (Pt) and iridium (Ir) are generally used as the electrode material of the lower electrode of such an actuator device, but Pt and Ir have a high Young's modulus and are hard, but have a high density and are heavy. Since the lower electrode also functions as a diaphragm, there is a problem that vibration responsiveness is lowered when Pt or Ir having a high density and heavy are used as the electrode material of the lower electrode.

  Here, a piezoelectric element including an upper layer containing a large amount of platinum and a lower electrode having a lower layer made of an alloy of titanium (Ti) and platinum is disclosed (see Patent Document 1). Since the lower electrode described in this document uses titanium and becomes lighter than the lower electrode made of platinum alone, it can be expected that the vibration response is improved.

JP 2000-252544 A (claims, paragraph [0018], etc.)

  However, since titanium is soft, there arises a problem that the rigidity of the lower electrode is lowered and the durability is lowered. Of course, such a problem exists not only in an actuator device mounted on a liquid ejecting head such as an ink jet recording head but also in an actuator device mounted on another device.

  In view of such circumstances, it is an object of the present invention to provide an actuator device and a liquid jet head that are excellent in vibration response and durability.

A first aspect of the present invention for solving the aforementioned problems is, a lower electrode provided on one surface of the substrate, a piezoelectric layer provided on the lower electrode, on which is provided on the piezoelectric layer comprising a piezoelectric element having electrodes, the two-the lower electrode, have a density elastic adjustment layer made of an alloy of Pt and _{TiO X (0.1 ≦ x ≦ 2} ), the lower electrode in the thickness direction When measured by a secondary ion mass spectrometer (SIMS), the portion where the Pt ions are detected weakest in the density elastic adjustment layer is closer to the piezoelectric layer side than the center in the thickness direction of the density elastic adjustment layer. The intensity Z _{1 of} Pt ions detected at the substrate-side boundary of the density elastic adjustment layer and the intensity Z ₂ of Pt ions at the portion where the Pt ions are detected weakest in the density elasticity adjustment layer. The ratio Z ₂ / Z ₁ is 0.05 to 0.3, and the density elasticity adjusting layer The ratio Z ₄ / Z ₃ between the Ti ion intensity Z ₃ detected at the substrate-side boundary and the Ti ion intensity Z ₄ at the portion where the Pt ion is detected weakest in the density elasticity adjusting layer is 0. 6 to 1.0, O ion intensity Z ₅ detected at the substrate-side boundary of the density elastic adjustment layer and O ion intensity at the portion where the Pt ion is detected weakest in the density elastic adjustment layer in an actuator device, wherein the ratio _Z 6 / _{Z 5} and Z ₆ is 1.5 to 4.0, in the range of.
In the first aspect, since the density elastic adjustment layer is made of an alloy with the density elastic adjustment material having a lower density and a higher Young's modulus than the electrode material, the vibration is higher than that of the actuator device having the lower electrode made only of the electrode material. Responsiveness and durability are reliably improved. In addition, since the intensity ratio of each ion at the boundary where the Pt ions are detected weakest when the density elastic adjustment layer is measured by SIMS is within the predetermined range, the density elastic adjustment layer has a piezoelectric layer side. Since TiO _X increases and the amount of Pt decreases, the rigidity of the lower electrode film increases and the durability of the diaphragm improves.

According to a second aspect of the present invention, in the actuator device according to the first aspect, the density elasticity adjusting layer has a higher Young's modulus on the piezoelectric layer side than on the substrate side.
In the second aspect, since the Young's modulus on the piezoelectric layer side is high, the rigidity of the lower electrode is increased and the durability is further improved.

According to a third aspect of the present invention, the lower electrode includes, in order from the substrate side, a Pt—Ti layer made of an alloy of Pt and Ti, a density elastic adjustment layer made of an alloy of TiO _X and Pt, and Pt a Pt layer consisting in an actuator device of the first or second aspect, characterized by comprising the Ir layer made of Ir, a.
In the third aspect, the Pt—Ti layer, the density elastic adjustment layer made of an alloy of TiO _X and Pt, the lower electrode having a structure in which the Pt layer and the Ir layer are laminated, and the response of the diaphragm In addition, the actuator device is excellent in durability.

According to a fourth aspect of the present invention, there is provided a liquid ejecting head including the actuator device according to any one of the first to third aspects.
In the fourth aspect, a liquid ejecting head having excellent piezoelectric characteristics and durability can be realized.
According to a fifth aspect of the present invention, there is provided an image recording apparatus comprising the liquid jet head according to the fourth aspect.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
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 having an actuator device according to Embodiment 1 of the present invention. FIG. 2 is a plan view of a main part of the ink jet recording head. FIG. 3 is a cross-sectional view taken along the line AA ′ of FIG. 2 and an enlarged cross-sectional view thereof.

  As shown in the figure, the flow path forming substrate 10 is made of a silicon single crystal substrate in the present embodiment, and one surface thereof is made of silicon dioxide previously formed by thermal oxidation, and is an elastic film having a thickness of 0.5 to 2 μm. 50 is formed. In the flow path forming substrate 10, a plurality of pressure generating chambers 12 partitioned by a partition wall 11 are arranged in parallel in the width direction (short direction). In addition, an ink supply path 14 and a communication path 15 are partitioned by a partition wall 11 on one end side in the longitudinal direction of the pressure generating chamber 12 of the flow path forming substrate 10. In addition, a communication portion 13 constituting a part of the reservoir 100 serving as an ink chamber (liquid chamber) common to the pressure generation chambers 12 is formed at one end of the communication passage 15. That is, the flow path forming substrate 10 is provided with a liquid flow path including a pressure generation chamber 12, a communication portion 13, an ink supply path 14, and a communication path 15.

  The ink supply path 14 communicates with one end side in the longitudinal direction of the pressure generation chamber 12 and has a smaller cross-sectional area than the pressure generation chamber 12. For example, in the present embodiment, the ink supply path 14 has a width smaller than the width of the pressure generation chamber 12 by narrowing the flow path on the pressure generation chamber 12 side between the reservoir 100 and each pressure generation chamber 12 in the width direction. It is formed with. As described above, 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. Further, each communication path 15 communicates with the side of the ink supply path 14 opposite to the pressure generation chamber 12 and has a larger cross-sectional area than the width direction (short direction) of the ink supply path 14. In the present embodiment, the communication passage 15 is formed with the same cross-sectional area as the pressure generation chamber 12.

  In other words, the flow path forming substrate 10 is connected to the pressure generation chamber 12, the ink supply path 14 having a smaller cross-sectional area in the short direction of the pressure generation chamber 12, the ink supply path 14, and the ink supply. A communication passage 15 having a cross-sectional area larger than the cross-sectional area in the short direction of the passage 14 and having the same cross-sectional area as the pressure generation chamber 12 is provided by being partitioned by a plurality of partition walls 11.

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 portion of each pressure generating chamber 12 on the side opposite to the ink supply path 14 is provided with an adhesive or It is fixed by a heat welding film or the like. The nozzle plate 20 has a thickness of, for example, 0.01 to 1 mm, a linear expansion coefficient of 300 ° C. or less, for example, 2.5 to 4.5 [× 10 ⁻⁶ / ° C.], glass ceramics, silicon It consists of a single crystal substrate or stainless steel.

On the other hand, an elastic film 50 made of silicon dioxide and having a thickness of, for example, about 1.0 μm is formed on the side opposite to the opening surface of the flow path forming substrate 10. For example, an insulator film 55 made of zirconium oxide (ZrO ₂ ) and having a thickness of, for example, about 0.3 to 0.4 μm is laminated. In the present embodiment, the elastic film 50 made of silicon dioxide (SiO ₂ ) and the insulator film 55 made of zirconium oxide (ZrO ₂ ) are provided on the flow path forming substrate 10. The type of film to be provided is not particularly limited. For example, SiO ₂ layer, ZrO ₂ layer, or Zr _1-X M _X O _Y (0.01 ≦ X ≦ 0.15, Y = 2.0 ± α, α is chemical A stoichiometrically acceptable value, M is a group IIA element, group IIIA element, or group IIIB element of the periodic table, and preferably M is at least one selected from Y and Ca). A layer may be sufficient and what laminated these layers may be sufficient. When a ZrO ₂ layer is provided as the insulator film 55, it is preferable that the (−111) plane is preferentially oriented in a columnar crystal having an average crystal grain size of 20 to 100 nm. The quality of the ZrO ₂ layer is good, the surface of the ZrO ₂ layer is smooth, and the adhesion with the lower layer and the upper layer of the ZrO ₂ layer is improved. Actuator device. When the surface of the ZrO ₂ layer is smoother than the rough surface, the adhesion with the layer in contact with the surface can be improved. In this specification, the average crystal grain size is the crystal grain size of the columnar crystal in the plane direction parallel to the electrode film, and is a value obtained by image processing of an image obtained by SEM or AFM. is there.

  On the insulator film 55, the lower electrode film 60 having a thickness of, for example, about 0.1 to 0.3 μm and lead zirconate titanate (PZT) having a thickness of, for example, about 0.5 to 5 μm are formed. A piezoelectric element 300 including the piezoelectric layer 70 and the upper electrode film 80 having a thickness of, for example, about 10 to 200 nm is formed.

  Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 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 this case, a portion that is configured by any one of the patterned electrodes and the piezoelectric layer 70 and in which piezoelectric distortion is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion 320. In the present embodiment, the lower electrode film 60 is used as a common electrode of the piezoelectric element 300 and the upper electrode film 80 is used as an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for convenience of a drive circuit and wiring. In any case, the piezoelectric active part 320 is formed for each pressure generating chamber 12. In the present embodiment, the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80 are patterned so that the width on the upper electrode film 80 side becomes narrow as shown in FIG. Has an inclined surface. In addition, here, the piezoelectric element 300 and the diaphragm that is displaced by driving the piezoelectric element 300 are collectively referred to as an actuator device. In the above-described example, the elastic film 50, the insulator film 55, and the lower electrode film 60 function as a diaphragm, but of course not limited to this. For example, the elastic film 50 and the insulator film 55 are not provided. Only the lower electrode film 60 may act as a diaphragm.

As shown in FIG. 3B, the lower electrode film 60 includes, in order from the insulator film 55 side, a Pt—Ti layer 500 made of an alloy of Pt and Ti, and TiO _X (0.1 ≦ x ≦ 2). In this structure, a TiO _X -Pt layer (density elasticity adjusting layer) 501 made of an alloy of Pt and Pt, a Pt layer 502 made of Pt, and an Ir layer 503 made of iridium (Ir) are laminated. In the present embodiment, the lower electrode film 60 has an electrode material of the lower electrode film 60, that is, TiO _X (0.1 ≦ x ≦ 2) having Pt as a main component of the lower electrode and having a lower density than Pt and Pt. ), The density is lower and lighter than the lower electrode film 60 made only of Pt, so that the vibration responsiveness is improved and the displacement characteristics of the actuator device are improved. improves. Further, since the density elastic adjustment layer 501 made of an alloy with TiO _X having a Young's modulus higher than that of Pt is provided, the average Young's modulus becomes higher and harder than the lower electrode film 60 made only of Pt. The actuator device is excellent in durability of the film 60.

Furthermore, when the lower electrode film 60 is measured in the thickness direction by a secondary ion mass spectrometer (SIMS), Pt ions, Ti ions, and O ions are detected as shown in FIG. The boundary of the layer 501 on the insulator film 55 side (vertical line portion indicated by the arrow (1) in FIG. 9) and the portion where the Pt ion is detected weakest in the density elastic adjustment layer 501 (in FIG. 9, The intensity ratio of each of these ions at the vertical line portion indicated by arrow (2) is within a predetermined range. Specifically, the strength Z _{1 of} Pt ions detected at the boundary of the density elastic adjustment layer 501 on the insulator film 55 side and the Pt ion in the portion where the density elastic adjustment layer 501 detects the weakest Pt ion. The ratio Z ₂ / Z ₁ to the strength Z ₂ is 0.05 to 0.3, and the Ti ion strength Z ₃ detected at the boundary of the density elastic adjustment layer 501 on the insulator film 55 side and the density elastic adjustment layer 501 The ratio Z ₄ / Z ₃ to the Ti ion intensity Z ₄ at the portion where Pt ions are detected most weakly is 0.6 to 1.0, and is detected at the boundary of the density elastic adjustment layer 501 on the insulator film 55 side. The ratio Z ₆ / Z ₅ of the intensity Z ₅ of the O ion to the intensity Z ₆ of the O ion in the portion where the Pt ion is detected weakest in the density elasticity adjusting layer 501 is 1.5 to 4.0 Within range. The portion where the Pt ions are detected weakest in the density elastic adjustment layer 501 is closer to the piezoelectric layer 70 than the center of the density elastic adjustment layer 501 in the thickness direction, and Ir ions begin to be substantially detected. . Further, the boundary of the density elastic adjustment layer 501 on the insulator film 55 side, that is, the boundary between the Pt—Ti layer 500 and the TiO _X —Pt layer (density elastic adjustment layer 501) in this embodiment was obtained by SIMS measurement. It can be judged from the chart, and Ti, O, and Pt ions have inflection points at this boundary portion.

If each value is within the above range, TiO _X is contained more on the piezoelectric layer 70 side than the insulator film 55 side, and Pt is contained more on the insulator film 55 side than the piezoelectric layer 70 side. Thus, since the TiO _X on the piezoelectric layer 70 side of the density elasticity adjusting layer 501 increases and the amount of Pt decreases, the rigidity of the lower electrode film 60 increases and the durability of the lower electrode film 60 improves. In addition, the ratio of the thickness which this density elasticity adjustment layer 501 occupies for the lower electrode film 60 is about 60 to 70%, and the thickness is about 130 to 180 nm, for example.

  Further, since lead (Pb) does not diffuse from the piezoelectric layer 70 into the lower electrode film 60 of the present embodiment, the lower electrode film 60 does not substantially contain Pb. For example, the lower electrode film 60 contains Pb. When the amount is measured, it is 0.1% by mass or less. Since Pb, which is a relatively high and heavy element, does not substantially contain Pb, the lower electrode film 60 has better vibration response than an actuator device containing Pb. Since the lower electrode film 60 does not substantially contain lead, there is no electrical insulating layer containing lead, for example, a layer made of titanium oxide and lead oxide, and the conductivity of the lower electrode film 60 is excellent. .

In the present embodiment, lead zirconate titanate (PZT) is used as the material (piezoelectric material) of the piezoelectric layer 70 constituting the piezoelectric element 300, but is not limited to PZT, and other ferroelectric piezoelectric properties. A material, or a relaxor ferroelectric material to which a metal such as niobium, nickel, magnesium, bismuth, or yttrium is added is used. As the composition, for example, PbTiO ₃ (PT), PbZrO ₃ (PZ), Pb (Zr _x Ti _1-x ) O ₃ (PZT), Pb (Mg _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PMN-PT), Pb (Zn _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PZN-PT), Pb (Ni _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PNN-PT), _{Pb (In 1/2 Nb 1/2) O} 3 -PbTiO 3 (PIN-PT), Pb (Sc 1/2 Ta 1/2) O 3 -PbTiO 3 (PST-PT), Pb (Sc 1/2 _{nb 1/2) O 3 -PbTiO 3 (} PSN-PT), biScO 3 -PbTiO 3 (BS-PT), BiYbO 3 -PbTiO 3 (BY-PT) and the like.

  Further, as the upper electrode film 80, an Ir layer is provided. Note that the upper electrode film 80 is not limited to Ir, and may be any of various metals such as Ir, Pt, W, Ta, and Mo, and alloys thereof and metal oxides such as iridium oxide.

  Each upper electrode film 80 which is an individual electrode of the piezoelectric element 300 is drawn from the vicinity of the end on the ink supply path 14 side and extended to the insulator film 55, for example, gold (Au) or the like. The lead electrode 90 which consists of is connected.

  Furthermore, on the flow path forming substrate 10 on which the piezoelectric element 300 is formed, the protective substrate 30 having the 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. Are joined by an adhesive 35. 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, the protective substrate 30 is provided with a reservoir portion 31 in a region facing the communication portion 13, and the reservoir portion 31 is communicated with the communication portion 13 of the flow path forming substrate 10 as described above. A reservoir 100 serving as an ink chamber common to the pressure generation chamber 12 is configured. 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 reservoir 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.

  In addition, a drive circuit (not shown) for driving the piezoelectric element 300 is fixed on the protective substrate 30, and the drive circuit and the lead electrode 90 are electrically connected via a connection wiring made of a conductive wire such as a bonding wire. Connected.

  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.

  On the protective substrate 30, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded. 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 reservoir portion 31. It has been stopped. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SUS) having a thickness of 30 μm). 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, the pressure is applied according to the recording signal from the drive circuit. By applying a voltage between each of the lower electrode film 60 and the upper electrode film 80 corresponding to the generation chamber 12, the elastic film 50, the insulator film 55, the lower electrode film 60, and the piezoelectric layer 70 are bent and deformed. The pressure in each pressure generating chamber 12 is increased, and ink droplets are ejected from the nozzle openings 21.

  Here, a method of manufacturing the ink jet recording head will be described with reference to FIGS. 4 to 8 are cross-sectional views in the longitudinal direction of the pressure generating chamber. First, as shown in FIG. 4A, a channel forming substrate wafer 110, which is a silicon wafer, is thermally oxidized in a diffusion furnace at about 1100 ° C. to form a silicon dioxide film 51 constituting an elastic film 50 on the surface thereof. To do. In this embodiment, a silicon wafer having a relatively thick film thickness of about 625 μm and a high rigidity is used as the flow path forming substrate wafer 110.

Next, as shown in FIG. 4B, an insulator film 55 made of zirconium oxide is formed on the elastic film 50 (silicon dioxide film 51). Specifically, after a zirconium (Zr) layer is formed on the elastic film 50 (silicon dioxide film 51) by, for example, sputtering, this 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.

  Next, as shown in FIG. 5A, a lower electrode film 60 composed of a Ti film 61, a Pt film 62, and an Ir film 63 is formed by a DC magnetron sputtering method or the like. Specifically, first, a Ti film 61 made of Ti is formed on the insulator film 55, and then a Pt film 62 made of Pt is formed on the Ti film 61. Then, an Ir film 63 made of Ir is formed on the Pt film 62. By providing the Ir film 63, the Ti of the Ti film 61 is prevented from diffusing into the piezoelectric layer 70 when the piezoelectric layer 70 is baked and crystallized in a later step, and the piezoelectric layer 70 is piezoelectric. The components of the body layer 70 can be prevented from diffusing toward the elastic film 50 side. Instead of the Ir film 63, a film containing at least one element selected from the group consisting of palladium (Pd), rhodium (Rh), ruthenium (Ru), and osmium (Os) as a main component may be provided. The density elasticity adjusting layer 501 having a SIMS measurement strength ratio within a predetermined range can be formed by appropriately adjusting the type and ratio of the metal film for forming the lower electrode film 60 and the heating conditions described later. it can.

  Next, on the lower electrode film 60, titanium (Ti) is applied by a sputtering method, for example, a DC sputtering method at least once, in this embodiment, twice, in this embodiment, a seed titanium layer (not shown) having a predetermined thickness. Form. This seed titanium layer serves as an orientation control layer that controls the orientation of the piezoelectric film that is formed on the seed titanium layer and becomes the piezoelectric layer 70. As described above, when the orientation control layer such as seed titanium is provided, the crystal of the piezoelectric film 72 grows with the titanium crystal as a nucleus, so that the crystallinity such as the orientation degree of the piezoelectric film 72 is greatly improved. Note that this orientation control layer may not be provided if there is no particular problem with the crystallinity of the piezoelectric layer 70. When the orientation control layer is provided, a layer containing a substance constituting the orientation control layer may remain between the lower electrode film 60 and the piezoelectric layer 70 of the manufactured actuator device. For example, when a seed titanium layer is provided on the lower electrode film 60 as an orientation control layer, a layer made of titanium oxide remains slightly.

  Next, a piezoelectric layer 70 made of lead zirconate titanate (PZT) is formed on the seed titanium layer thus formed. Here, in this embodiment, a so-called sol in which a metal organic material is dissolved and dispersed in a solvent is applied, dried, and gelled to form a piezoelectric precursor film 71, which is further baked at a high temperature, thereby forming a piezoelectric film made of a metal oxide. The piezoelectric layer 70 is formed using a so-called sol-gel method for obtaining the body layer 70. Moreover, it is not limited to the sol-gel method, For example, you may use the MOD (Metal-Organic Decomposition) method, sputtering method, etc. The method for manufacturing the piezoelectric layer 70 is not limited as long as it is a method of firing and crystallizing a thin film piezoelectric precursor film.

As a specific procedure for forming the piezoelectric layer 70, first, as shown in FIG. 5B, a piezoelectric precursor film 71 that is a PZT precursor film is formed on the lower electrode film 60. That is, a sol (solution) containing a metal organic compound (lead zirconate titanate) is applied onto the flow path forming substrate 10 on which the lower electrode film 60 is formed, and a piezoelectric precursor having a film thickness of about 0.1 μm, for example. A film 71 is formed (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). The degreasing referred to here is to release the organic component contained in the piezoelectric precursor film 71 as, for example, NO ₂ , CO ₂ , H ₂ O or the like.

  Next, as shown in FIG. 5C, the piezoelectric precursor film 71 is crystallized by being heated to a predetermined temperature and held for a predetermined time to form a piezoelectric film 72 (firing step). Examples of the heating apparatus used in the drying process, the degreasing process, and the baking process include an RTA (Rapid Thermal Annealing) apparatus and a hot plate that are heated by irradiation with an infrared lamp.

  Next, as illustrated in FIG. 6A, a resist 400 having a predetermined shape is formed on the piezoelectric film 72. Next, as shown in FIG. 6B, the first layer of the lower electrode film 60 and the piezoelectric film 72 is simultaneously patterned using the resist 400 as a mask so that the side surfaces thereof are inclined.

  Next, after the resist 400 is peeled off, the piezoelectric film forming process including the coating process, the drying process, the degreasing process, and the baking process described above is repeated a plurality of times to form the piezoelectric layer 70 including the plurality of piezoelectric films 72. Then, as shown in FIG. 6C, a piezoelectric layer 70 having a predetermined thickness composed of a plurality of layers of piezoelectric films 72 is formed. For example, when the film thickness per sol is about 0.1 μm, the entire film thickness of the piezoelectric layer 70 composed of ten piezoelectric films 72 is about 1.1 μm, for example. In the present embodiment, the piezoelectric film 72 is provided by being laminated, but only one layer may be provided.

In this way, in the process of forming the piezoelectric layer 70, the Ti film 61, the Pt film 62, and the Ir film 63 are also heated, and the alloyed lower electrode film 60 is formed. A density elasticity adjusting layer 501 made of an alloy of TiO _X and Pt is formed in the lower electrode film 60, and the structure of the lower electrode film 60 is made of an alloy of Pt and Ti in order from the insulator film 55 side. A Pt—Ti layer 500, a density elastic adjustment layer 501 made of an alloy of TiO _X and Pt, a Pt layer 502 made of Pt, and an Ir layer 503 made of Ir. The lower electrode film 60 obtained by this manufacturing method does not substantially contain Pb. This is because Pb derived from the piezoelectric material (PZT) of the piezoelectric layer 70 does not diffuse into the lower electrode film 60.

  After the piezoelectric layer 70 is formed in this way, as shown in FIG. 7A, an upper electrode film 80 made of iridium (Ir) is formed over the entire surface of the piezoelectric layer 70 by a sputtering method or the like. Then, patterning is performed in a region facing each pressure generation chamber 12 to form the piezoelectric element 300 including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. The patterning of the piezoelectric layer 70 and the upper electrode film 80 can be performed collectively by dry etching via a resist (not shown) formed in a predetermined shape. In such dry etching, when the side surfaces of the resist are inclined in advance, the piezoelectric layer 70 and the upper electrode film 80 are patterned so that the width on the upper electrode film 80 side is narrow, and the side surfaces are inclined. It becomes a surface.

  Next, as shown in FIG. 7B, a 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 a mask pattern made of, for example, a resist or the like. Patterning is performed for each piezoelectric element 300 via (not shown).

  Next, as shown in FIG. 7C, a protective substrate wafer 130 that is a silicon wafer and serves as a plurality of protective substrates 30 is placed on the flow path forming substrate wafer 110 on the piezoelectric element 300 side via an adhesive 35. Join. Since the protective substrate wafer 130 has a thickness of, for example, about 400 μm, the rigidity of the flow path forming substrate wafer 110 is remarkably improved by bonding the protective substrate wafer 130. Here, after the protective substrate wafer 130 is bonded to the flow path forming substrate wafer 110, the flow path forming substrate wafer 110 is thinned to a predetermined thickness.

  Next, as shown in FIG. 8A, the flow path forming substrate wafer 110 is thinned to a certain thickness. Further, 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. 8B, anisotropic etching (wet etching) using an alkali solution such as KOH is performed on the flow path forming substrate wafer 110 through the mask film 52, whereby the piezoelectric element 300 is formed. 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. Then, after removing the silicon dioxide film 51 on the surface of the flow path forming substrate wafer 110 opposite to the protective substrate wafer 130, the nozzle plate 20 having the nozzle openings 21 formed therein is bonded, and the protective substrate wafer is also formed. The compliance substrate 40 is bonded to 130, and the flow path forming substrate wafer 110 and the like are divided into a single chip size flow path forming substrate 10 as shown in FIG. To do.

Hereinafter, it demonstrates further in detail based on an Example and a comparative example.
Example 1
Based on the above embodiment, an actuator device was manufactured. Specifically, as shown in the structure before film formation in PZT in Table 1, a SiO ₂ film having a thickness of 1 μm and a ZrO ₂ film having a thickness of 400 nm are sequentially provided on a silicon substrate having a thickness of 625 μm. A 70 nm thick Ti film, a 80 nm thick Pt film, and a 10 nm thick Ir film were formed by sputtering. Thereafter, using a sol having a PZT composition of Pb / (Zr + Ti) = 1.18 and Zr / (Zr + Ti) = 0.517, a piezoelectric layer made of PZT was formed on the lower electrode film via an orientation control layer. . For the piezoelectric layer, the first piezoelectric precursor film formed using the sol is fired, and then the firing process is performed three times each time three piezoelectric precursor films are formed on the piezoelectric precursor film. Thus, a piezoelectric layer having a thickness of 1.1 μm was prepared. The firing conditions at this time were set to 700 ° C. for 5 minutes for all four times. Thereafter, an upper electrode made of Ir having a thickness of 50 nm was provided on the piezoelectric layer to manufacture an actuator device. Table 1 shows the structure of the manufactured actuator device.

(Example 2)
The actuator device was manufactured by setting the thickness of the Ti film to 50 nm.

(Comparative Example 1)
The actuator device was manufactured by setting the thickness of the Ti film to 20 nm.

(Test Example 1)
An actuator apparatus that is peeled off the piezoelectric layer and the ZrO ₂ film from the actuator device prepared in Examples 1-2 and Comparative Example 1 were measured by a secondary ion mass spectrometer over the thickness direction (SIMS) . The results are shown in FIG. 9 for Example 1, FIG. 10 for Example 2, and FIG. 11 for Comparative Example 1. In each figure, the left side is the insulator film (ZrO ₂ ) 55 side, and the right side is the piezoelectric layer 70 side. In the figure, vertical lines other than the shortest vertical line (the vertical line indicated by the arrow (2)) in FIGS. 9 and 10 represent the boundaries of the layers constituting the lower electrode film 60.

As shown in FIGS. 9 and 10, in Example 1 and Example 2, the lower electrode film 60 includes, in order from the ZrO ₂ film side, a Pt—Ti layer 500 made of an alloy of Pt and Ti, TiO _X (X = 0.1 to 2) and a TiO _x -Pt layer (density elastic adjustment layer) 501 made of an alloy of Pt, a Pt layer 502 made of Pt, and an Ir layer 503 made of Ir. Since it has the density elastic adjustment layer 501 made of Pt, which is an electrode material, and TiO _X, which is a material having a lower density and higher Young's modulus than Pt, the density is lower and lighter than the lower electrode film 60 made only of Pt. In addition, since the average Young's modulus becomes high and hard, the actuator device was excellent in vibration response and durability.

On the other hand, in Comparative Example 1, as shown in FIG. 11, in order from the ZrO ₂ film side, a Pt—Ti layer made of an alloy of Pt and Ti, Pt, TiO _X (X = 0.1-2), and Ir Pt—TiO _X —Ir—PbO _X layer made of an alloy with PbO _X (X = 0.1-2), TiO _X (X = 0.1-2) and PbO _X (X = 0.1-2) TiO _X -PbO _X layer made of an alloy with Ir, and Ir-PbO _X layer made of an alloy of Ir and PbO _X (X = 0.1-2). Thus, Pb was diffused into the lower electrode film, and an electrical insulating layer (TiO _X -PbO _X layer) was formed.

(Test Example 2)
For Example 1 and Example 2, from FIGS. 9 and 10, the intensity of Pt ions detected at the boundary (the vertical line portion indicated by arrow (1)) of the density elastic adjustment layer 501 on the insulator film 55 side. the ratio _Z 2 / _{Z 1} between the intensity _{Z 2} of Pt ions in Z ₁ and part density elastic adjustment layer 501 Pt ions in is weakest detected (arrow (indicated vertical line part 2)), The Ti ion intensity Z ₃ detected at the boundary of the density elastic adjustment layer 501 on the insulator film 55 side and the Ti ion intensity Z ₄ at the portion where the Pt ion is detected weakest in the density elastic adjustment layer 501 The ratio Z ₄ / Z ₃ , the intensity Z _{5 of} O ions detected at the boundary of the density elastic adjustment layer 501 on the insulator film 55 side, and the portion where Pt ions are detected weakest in the density elastic adjustment layer 501 A ratio Z ₆ / Z ₅ with the intensity Z _{6 of} O ions was determined. The results are shown in Table 1.

As a result, in Example 1 and Example 2, since the TiO _X on the piezoelectric layer 70 side of the density elastic adjustment layer 501 increases and the Pt amount decreases, the rigidity of the lower electrode film 60 increases, and the lower electrode An actuator device having excellent durability of the film 60 was obtained.

It should be noted that the silicon substrate, the SiO ₂ film, the ZrO ₂ film, the Ti film, the Pt film, the Ir film, the orientation control layer, the thickness of the piezoelectric layer, the PZT composition, etc. These are merely examples, and it is added that the structure of the claims is not limited to the first and second embodiments.

(Other embodiments)
Although one embodiment of the present invention has been described above, the basic configuration of the present invention is not limited to the above-described first embodiment. For example, in the first embodiment, in order to lower electrode film 60 from the insulating layer 55 side, and Pt-Ti layer 500 made of an alloy of Pt and Ti, _TiO X -Synthesis of Pt layer of an alloy of TiO _X and Pt ( The density elastic adjustment layer 501), the Pt layer 502 made of Pt, and the Ir layer 503 made of iridium are stacked. However, the lower electrode film 60 includes the density elastic adjustment layer 501, and the density elastic adjustment layer 501. As long as the ratio of each ion detected when SIMS is measured is within a predetermined range, the position of the density elastic adjustment layer 501 and the composition of other layers are not particularly limited.

  In the first embodiment described above, the ink jet recording head has been described as an example of the liquid ejecting head. However, the present invention is widely intended for all liquid ejecting heads, and is a liquid ejecting liquid other than ink. Of course, the present invention can also be applied to an ejection 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. Needless to say, the present invention can be applied not only to an actuator device mounted on a liquid jet head (such as an ink jet recording head) but also to an actuator device mounted on any device.

FIG. 2 is an exploded perspective view illustrating a schematic configuration of the recording head according to the first embodiment. FIG. 3 is a plan view of a main part 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. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. FIG. 4 is a diagram showing the SIMS measurement result of the lower electrode film in Example 1. FIG. 6 is a diagram showing the SIMS measurement result of the lower electrode film in Example 2. 6 is a diagram showing SIMS measurement results of a lower electrode film in Comparative Example 1. FIG.

Explanation of symbols

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 Reservoir part, 32 Piezoelectric element holding part, 40 Compliance board, 60 Lower electrode film 70 Piezoelectric layer, 71 Piezoelectric precursor film, 72 Piezoelectric film, 80 Upper electrode film, 90 Lead electrode, 100 Reservoir, 300 Piezoelectric element, 320 Piezoelectric active part, 500 Pt-Ti layer, 501 TiO _X − Pt layer (density elastic adjustment layer), 502 Pt layer, 503 Ir layer

Claims (5)

Comprising a lower electrode provided on one surface of the substrate, and the lower piezoelectric body provided on the electrode layer, the piezoelectric element having an electrode on which is provided on the piezoelectric layer,
The lower electrode, have a density elastic adjustment layer made of an alloy of Pt and _{TiO X (0.1 ≦ x ≦ 2} ),
When the lower electrode is measured by a secondary ion mass spectrometer (SIMS) in the thickness direction, the portion where the Pt ion is detected weakest in the density elastic adjustment layer is the thickness direction of the density elastic adjustment layer. It is on the piezoelectric layer side from the center,
A ratio Z between the intensity Z _{1 of} Pt ions detected at the boundary of the density elastic adjustment layer on the substrate side and the intensity Z ₂ of Pt ions in the portion where the Pt ions are detected weakest in the density elastic adjustment layer ₂ / _{Z 1} is 0.05 to 0.3,
Ratio Z of Ti ion intensity Z ₃ detected at the substrate-side boundary of the density elastic adjustment layer and Ti ion intensity Z ₄ at a portion where Pt ions are detected weakest in the density elastic adjustment layer Z ₄ / _{Z 3} is 0.6 to 1.0,
The ratio Z between the O ion intensity Z ₅ detected at the substrate-side boundary of the density elastic adjustment layer and the O ion intensity Z ₆ at the portion where the Pt ion is detected weakest in the density elastic adjustment layer ₆ / Z ₅ is in the range of 1.5 to 4.0.   2. The actuator device according to claim 1, wherein the density elasticity adjusting layer has a Young's modulus on the piezoelectric layer side higher than that on the substrate side. The lower electrode is made of, in order from the substrate side, a Pt—Ti layer made of an alloy of Pt and Ti, a density elastic adjustment layer made of an alloy of TiO _X and Pt, a Pt layer made of Pt, and Ir. the actuator device according to claim 1 or 2, characterized by comprising the Ir layer. Liquid jet head characterized by including the actuator device according to any one of claims 1-3. An image recording apparatus comprising the liquid jet head according to claim 4 .

Images