JP5024564B2 - Actuator device and liquid jet head - Google Patents

Description

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

  An actuator device including a piezoelectric element that is displaced by applying a voltage is mounted on, for example, a liquid ejecting head that ejects liquid droplets. As such a liquid ejecting head, for example, pressure generation that communicates with a nozzle opening is performed. There is known an ink jet recording head in which a part of a chamber is constituted by a diaphragm, and the diaphragm is deformed by a piezoelectric element to pressurize ink in a pressure generating chamber and eject ink droplets from a nozzle opening. Two types of inkjet recording heads have been put into practical use: those equipped with a piezoelectric actuator device in a longitudinal vibration mode that extends and contracts in the axial direction of the piezoelectric element, and those equipped with a piezoelectric actuator device in a flexural vibration mode. Yes.

  The former can change the volume of the pressure generation chamber by bringing the end face of the piezoelectric element into contact with the vibration plate, and it is possible to manufacture a head suitable for high-density printing, while the piezoelectric element is arranged in an array of nozzle openings. There is a problem that the manufacturing process is complicated because a difficult process of matching the pitch into a comb-like shape and an operation of positioning and fixing the cut piezoelectric element in the pressure generating chamber are necessary. On the other hand, the latter can flexibly vibrate, although a piezoelectric element can be built on the diaphragm by a relatively simple process of sticking a green sheet of piezoelectric material according to the shape of the pressure generation chamber and firing it. There is a problem that a certain amount of area is required for the use of, and high-density arrangement is difficult. In addition, in order to eliminate the inconvenience of the latter, a uniform piezoelectric material layer is formed by a film forming technique over the entire surface of the diaphragm, and this piezoelectric material layer is cut into a shape corresponding to the pressure generating chamber by a lithography method. Some have piezoelectric elements formed so as to be independent for each pressure generating chamber.

For example, lead zirconate titanate (PZT) is used as the material of the piezoelectric material layer constituting such a piezoelectric element. In this case, when the piezoelectric material layer is fired, the lead component of the piezoelectric material layer is diffused into the silicon oxide (SiO ₂ ) film that is provided on the surface of the flow path forming substrate made of silicon (Si) and forms the diaphragm. Resulting in. The diffusion of the lead component causes the melting point of silicon oxide to drop, and there is a problem that it is melted by the heat at the time of firing the piezoelectric material layer. In order to solve such a problem, for example, a zirconium oxide (ZrO ₂ ) layer constituting a diaphragm is provided on the silicon oxide film, thereby preventing diffusion of a lead component from the piezoelectric material layer to the silicon oxide film. There is something. (For example, refer to Patent Document 1).

Japanese Patent Application Laid-Open No. 11-204849 (FIGS. 1, 2, and 5)

  However, in the actuator device having such a structure, the adhesion force between the zirconium oxide layer and the lower electrode provided thereon, and the adhesion force between the silicon oxide film and the zirconium oxide layer, which are the bases of the zirconium oxide layer, are not sufficient. However, when the actuator device is driven to bend and vibrate, there is a problem that the lower electrode and the base may be peeled off from the zirconium oxide layer. 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, an object of the present invention is to provide an actuator device and a liquid jet head that are excellent in adhesion between a lower electrode and a zirconium oxide layer.

A first aspect of the present invention that solves the above problems includes a SiO ₂ layer formed on a substrate, a ZrO ₂ layer formed on the SiO ₂ layer, and a lower electrode formed on the ZrO ₂ layer. And a piezoelectric layer formed on the lower electrode, and an upper electrode formed on the piezoelectric layer, and the ZrO ₂ layer has a protrusion on the surface on the lower electrode side, The protrusion has a height of 16.0 to 40.6 nm and a plan view size of 0.3 to 0.5 μm in diameter, and is 1.11 × 10 ^{7 to} 1.25 × 10 on the ZrO ₂ layer. It exists in the actuator apparatus characterized by existing with the density of ⁷ piece / cm < ² > .
In the first aspect, the ZrO ₂ layer has a protrusion Jo Tokoro, an excellent actuator device to the adhesion between the lower electrode and the ZrO ₂ layer.

According to a second aspect of the present invention, the lower electrode has a protrusion protruding from the protrusion of the ZrO ₂ layer on the surface of the piezoelectric layer side, and the protrusion has a height of 16. a diameter 0.3~0.5μm size in plan view in 0～40.6Nm, present at a density of 1.11 × ^{10 7} ~1.25 × ¹⁰ 7 cells / cm ² on the lower electrode The actuator device according to the first aspect is characterized in that.
In the second aspect, the lower electrode has a convex portion on the projecting portion of the ZrO ₂ layer, an excellent actuator device to the adhesion between the lower electrode and the ZrO ₂ layer.

  In a third aspect of the present invention, the ZrO ₂ In the actuator device according to the first or second aspect, the layer is a columnar crystal and has a (−111) plane preferential orientation.
  In a fourth aspect of the present invention, the ZrO ₂ The layer is formed by oxidizing the Zr layer, and the protrusion is formed by crystal growth of Zr, has a height of 16.0 to 40.6 nm, and has a diameter in plan view of 0 mm. 1.11 × 10 protruding at 3 to 0.5 μm ⁷ ~ 1.25 × 10 ⁷ Piece / cm ² In the actuator device according to any one of the first to third aspects, the special crystal region having a density of 1 is formed by oxidation.
  In the fourth aspect, ZrO formed by oxidizing a Zr layer formed to have a predetermined special crystal region on the surface on the lower electrode side. ₂ The layer has a predetermined protrusion corresponding to the special crystal region, and is a base SiO 2 ₂ Layer and lower electrode and ZrO ₂ The actuator device has excellent adhesion to the layer.

According to a fifth aspect of the present invention, there is provided a liquid ejecting head including the actuator device according to any one of the first to fourth aspects as liquid ejecting means for ejecting liquid.
In the fifth aspect, since the use of superior actuator device to the adhesion between the lower electrode and the like and the ZrO ₂ layer, the peeling of the lower electrode or the like and the ZrO ₂ layer by the driving of the actuator device is prevented, the durability A liquid jet head with excellent performance can be realized.

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. FIG. 3 is an enlarged cross-sectional view of a main part of the recording head according to the first embodiment. It is a principal part expanded sectional view of a Zr layer. It is a principal part enlarged plan view of a Zr layer. 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.

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. 3 is a cross-sectional view taken along the line AA ′ of FIG. 2, FIG. 4 is an enlarged view of a main part of FIG. 3, and FIG. 5 is a diagram of a zirconium (Zr) layer that is a precursor of a zirconium oxide (ZrO ₂ ) layer. FIG. 6 is an enlarged plan view of a main part of a Zr layer that is a precursor of a ZrO ₂ layer.

As shown in the figure, the flow path forming substrate 10 is composed of a silicon single crystal substrate having a plane orientation (110) in the present embodiment, and one surface thereof is composed of silicon dioxide (SiO ₂ ) previously formed by thermal oxidation. An elastic film 50 having a thickness of 0.5 to 2 μm 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. Further, at one end of the communication passage 15, a communication portion 13 is formed that constitutes a part of the reservoir 100 that serves as a common ink chamber (liquid chamber) for each pressure generating chamber 12. 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 this 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. A ZrO ₂ layer 55 made of zirconium oxide (ZrO ₂ ) and having a thickness of, for example, about 0.3 to 0.4 μm is laminated.

On the ZrO ₂ layer 55, a lower electrode film 60 having a thickness of, for example, about 0.1 to 0.2 μm, a piezoelectric layer 70 having a thickness of, for example, about 0.5 to 5 μm, and a thickness of, for example, A piezoelectric element 300 composed of the upper electrode film 80 of 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 narrower as shown in FIG. It has become. Also, 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 example described above, the elastic film 50, ZrO ₂ layer 55 and the lower electrode film 60 function as a vibration plate, not of course limited thereto, without providing the elastic film 50, ZrO ₂ layer 55 and the lower The electrode film 60 may act as a diaphragm.

In the present invention, the ZrO ₂ layer 55 is formed by oxidizing the Zr layer 401 made of zirconium (Zr) provided on the elastic film 50 on the flow path forming substrate 10. The Zr layer 401 is formed by growing a Zr crystal as shown in the enlarged cross-sectional view of the main part in FIG. 5 and the enlarged plan view of the main part in FIG. The special crystal region 402 is formed so as to protrude to the surface, that is, the side on which the lower electrode film 60 is provided. The special crystal region 402 protrudes with a height of 10 to 100 nm and a plan view size of 0.1 to 1 μm in diameter, and 1.0 × 10 ^{6 to} 1.0 × 10 ⁸ pieces / cm on the surface of the Zr layer 401. ² and preferably projecting with a height of 16.0 to 40.6 nm and a plan view size of 0.3 to 0.5 μm in diameter, and 1.11 × 10 ^{7 to} 1.25 on the surface of the Zr layer 401. It is formed at a density of × 10 ⁷ pieces / cm ² . When the Zr layer 401 is formed by growing a Zr crystal from the elastic film 50 side, the special crystal region 402 is higher in the thickness direction of the Zr layer 401 than the Zr crystal in other regions. It is comprised by the crystal | crystallization of this. Therefore, by forming a flat Zr layer and then forming a protruding region by partially laminating Zr crystals on the Zr layer, or by patterning the surface after forming a flat Zr layer It is different from what formed the protruding region. In the present embodiment, the special crystal region 402 is composed of a Zr crystal group having a columnar crystal with a grain size of about 20 to 100 nm in plan view and a (002) plane orientation degree of 70% or more. Here, “degree of orientation” refers to a ratio of diffraction intensities generated when the Zr layer is measured by the X-ray diffraction wide angle method. Specifically, when the Zr layer is measured by the X-ray diffraction wide angle method, peaks of diffraction intensity corresponding to the (100) plane, the (002) plane, and the (101) plane are generated. "Means the ratio of the peak intensity corresponding to the (002) plane to the sum of the peak intensity corresponding to each of these planes.

When having such a ZrO ₂ layer 55, the adhesion between the elastic membrane 50 and the ZrO ₂ layer 55 made of SiO ₂ as a base of ZrO ₂ layer 55 is excellent. Further, adhesion between the lower electrode film 60 and the ZrO ₂ layer 55 provided on the ZrO ₂ layer 55 is excellent. Therefore, peeling of the elastic film 50 and the lower electrode film 60 from the ZrO ₂ layer 55 when the actuator device is driven can be prevented.

Since the ZrO ₂ layer 55 is formed by oxidizing the Zr layer 401 having the special crystal region 402 protruding from the surface, the lower electrode film 60 is formed on the ZrO ₂ layer 55 as shown in FIG. On the surface on the side, a protrusion 403 is formed by oxidizing the special crystal region 402. The protrusion 403 of the ZrO ₂ layer 55 has a height of 10 to 100 nm and a size in a plan view of 0.1 to 1 μm in diameter, and is 1.0 × 10 ⁶ to 1.0 × on the ZrO ₂ layer 55. 10 ⁸ pieces / cm ² , preferably 16.0 to 40.6 nm in height and 0.3 to 0.5 μm in diameter in plan view, and 1.11 × on the ZrO ₂ layer 55. 10 ⁷ to 1.25 is present at a density of × 10 ⁷ cells / cm ^2. In the present embodiment, the ZrO ₂ layer 55 is a columnar crystal having a particle size of about 20 to 100 nm, and the (−111) plane is preferentially oriented.

Then, the lower electrode film 60 because it was provided on the ZrO ₂ layer 55 having a projecting portion 403, as shown in FIG. 4, the surface of the piezoelectric layer 70 side, the protruding portions of the ZrO ₂ layer 55 It has a convex portion 404 protruding by 403. The convex portion 404 of the lower electrode film 60 has a height of 10 to 100 nm and a size in plan view of a diameter of 0.1 to 1 μm, and is 1.0 × 10 ⁶ to 1.0 × on the lower electrode film 60. The density is 10 ⁸ pieces / cm ² , and the height is preferably 16.0 to 40.6 nm and the size in plan view is 0.3 to 0.5 μm in diameter, and 1.11 × on the lower electrode film 60. 10 ⁷ to 1.25 is present at a density of × 10 ⁷ cells / cm ^2.

Examples of the lower electrode film 60 in this embodiment include various metals such as iridium (Ir), platinum (Pt), titanium (Ti), and tungsten (W), and alloys thereof. In the present embodiment, as a material (piezoelectric material) of the piezoelectric layer 70 constituting the piezoelectric element 300, for example, a ferroelectric piezoelectric material such as lead zirconate titanate (PZT), niobium, nickel, A relaxor ferroelectric or the like to which a metal such as 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, the upper electrode film 80 may be any of various metals such as Ir, Pt, tungsten (W), tantalum (Ta), and molybdenum (Mo), and alloys thereof and metal oxides such as iridium oxide. Is mentioned.

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 ZrO ₂ layer 55, for example, gold (Au) or the like. The lead electrode 90 which consists of is connected. A voltage is selectively applied to each piezoelectric element 300 via the lead electrode 90.

  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. In addition, 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 the 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 the lower electrode film 60 and the upper electrode film 80 corresponding to the generation chamber 12, the elastic film 50, the ZrO ₂ layer 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. In the present embodiment, because of the high adhesion between the lower electrode film 60 and the elastic film 50 and the ZrO ₂ layer 55, the lower electrode film 60 and the elastic film 50 be deformed deflection by driving the actuator device ZrO ₂ layer 55 Since it does not peel off, it has excellent durability.

  Here, a method of manufacturing the ink jet recording head will be described with reference to FIGS. 7 to 11 are cross-sectional views in the longitudinal direction of the pressure generating chamber. First, as shown in FIG. 7A, a flow path forming substrate wafer 110, which is a silicon wafer, is thermally oxidized in a diffusion furnace at about 1100 ° C., and a silicon dioxide film 51 constituting an elastic film 50 is formed on the surface thereof. To do. In the present 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. 7B, a Zr layer 401 is formed on the elastic film 50 (silicon dioxide film 51). The Zr layer 401 is formed by crystal growth of Zr, and protrudes with a height of 10 to 100 nm and a plan view size of 0.1 to 1 μm in diameter on the surface on which the lower electrode film 60 is formed. The special crystal region 402 has a density of 1.0 × 10 ^{6 to} 1.0 × 10 ⁸ / cm ² , and preferably has a height of 16.0 to 40.6 nm and a size in plan view of a diameter of 0. The film is formed so that the special crystal region 402 protruding at 3 to 0.5 μm is formed at a density of 1.11 × 10 ^{7 to} 1.25 × 10 ⁷ pieces / cm ² . When the Zr layer 401 is formed by growing a Zr crystal from the elastic film 50 side, for example, the special crystal region 402 is preferentially formed in the thickness direction of the Zr layer 401 over the normal Zr crystal. The film can be formed so that a region where crystals grow is generated, and can be composed of a Zr crystal group grown higher than a normal Zr crystal.

Specifically, using a DC sputtering method, film formation temperature: room temperature (23 ° C.) to 300 ° C., Ar pressure during film formation: 1 Pa or less, output power density: 3 to 30 kW / m ² , target (Zr) The Zr layer 401 in which the special crystal region 402 is formed can be formed by adjusting the balance of the respective conditions within the range of the distance between the elastic film 50 and the elastic film 50: 60 to 180 mm. For example, although depending on other conditions, the higher the film formation temperature, the easier it is to obtain the special crystal region 402 having a larger size in plan view, and the lower the Ar pressure, the easier it is to form the special crystal region 402. Further, although depending on other conditions, the higher the (002) plane orientation degree of the Zr layer 401 is, for example, 70% or more, the special crystal region 402 is more likely to be formed.

After the Zr layer 401 is formed, the Zr layer 401 is oxidized to form a ZrO ₂ layer 55 as shown in FIG. 7C. In the present embodiment, the ZrO ₂ layer 55 is formed by thermally oxidizing the Zr layer 401 in a diffusion furnace at 500 to 1200 ° C., for example. In this embodiment, the Zr layer 401 is oxidized by dry oxidation, but the Zr layer 401 may be oxidized by wet oxidation. In the ZrO ₂ layer 55 formed in this way, the protrusion 403 as shown in FIG. 4 is formed by oxidizing the special crystal region 402 of the Zr layer 401. The height, size, and density of the protrusions 403 of the ZrO ₂ layer 55 correspond to the special crystal region 402 of the Zr layer 401, the height is 10 to 100 nm, and the size in plan view is 0. 1 to 1 μm and formed on the surface of the ZrO ₂ layer 55 at a density of 1.0 × 10 ^{6 to} 1.0 × 10 ⁸ pieces / cm ² .

Thereafter, for example, titanium (Ti), platinum (Pt), and iridium (Ir) are stacked on the ZrO ₂ layer 55 by sputtering or the like, so that the lower electrode film 60 is formed as shown in FIG. Form. In the lower electrode film 60 formed in this way, as shown in FIG. 4, convex portions 404 are formed on the protruding portions 403 of the ZrO ₂ layer 55. The height, size, and density of the convex portions 404 of the lower electrode film 60 depend on the film forming conditions of the lower electrode film 60 and the protruding portions 403 of the ZrO ₂ layer 55. For example, the DC sputtering method When the lower electrode film 60 is formed at a film forming temperature of 23 to 100 ° C., an Ar pressure during film formation: 0.3 to 1 Pa, and an output power density of 3 to 30 kW / m ² , The height is 10 to 100 nm and the size in plan view is 0.1 to 1 μm in diameter, and is formed on the lower electrode film 60 at a density of 1.0 × 10 ^{6 to} 1.0 × 10 ⁸ pieces / cm ^2. The

  Next, a piezoelectric layer 70 made of lead zirconate titanate (PZT) or the like is formed on the lower electrode film 60. Here, in the present embodiment, a so-called sol-gel in which a so-called sol obtained by dissolving and dispersing a metal organic substance in a solvent is applied, dried, gelled, and further fired at a high temperature to obtain a piezoelectric layer 70 made of a metal oxide. The piezoelectric layer 70 is formed using the method. Moreover, it is not limited to a sol-gel method, For example, you may use the MOD (Metal-Organic Decomposition) method etc. Further, other sputtering methods may be used.

As a specific procedure for forming the piezoelectric layer 70, first, as shown in FIG. 8B, a piezoelectric precursor film 71 that is a PZT precursor film is formed on the lower electrode film 60. That is, the piezoelectric precursor film 71 is formed by applying a sol (solution) containing a metal organic compound (lead zirconate titanate) on the flow path forming substrate 10 on which the lower electrode film 60 is formed by spin coating or the like. (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. 8C, the piezoelectric precursor film 71 is crystallized by being heated to a predetermined temperature and held for a predetermined time, thereby forming 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. 9A, a resist 400 having a predetermined shape is formed on the piezoelectric film 72. Next, as shown in FIG. 9B, the lower electrode film 60 and the first piezoelectric film 72 are 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. 9C, a piezoelectric layer 70 having a predetermined thickness composed of a plurality of layers of piezoelectric films 72 is formed. For example, the film thickness per one time of the sol is made very thin, and the film thickness of the entire piezoelectric layer 70 composed of a plurality of layers of piezoelectric films is set to about 1 to 3 μm. In the present embodiment, the piezoelectric film 72 is provided by being laminated. However, the film thickness of one layer of the piezoelectric film 72 may be increased to constitute only one layer. The piezoelectric layer 70 thus obtained is smooth and has no protruding region.

  After the piezoelectric layer 70 is formed, as shown in FIG. 10A, an upper electrode film 80 made of Ir is formed over the entire surface of the piezoelectric layer 70 by a sputtering method or the like, and each pressure generating chamber 12 is formed. The piezoelectric element 300 composed of the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80 is formed by patterning in a region opposite to the substrate. 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. 10B, after forming the lead electrode 90 made of, for example, gold (Au) over the entire surface of the flow path forming substrate wafer 110, for example, a mask pattern made of a resist or the like. Patterning is performed for each piezoelectric element 300 via (not shown).

  Next, as shown in FIG. 10C, a protective substrate wafer 130 that is a silicon wafer and serves as a plurality of protective substrates 30 is disposed on the piezoelectric element 300 side of the flow path forming substrate wafer 110 via an adhesive 35. Join. Since the protective substrate wafer 130 has a thickness of, for example, about several hundred μm, the rigidity of the flow path forming substrate wafer 110 is remarkably improved by bonding the protective substrate wafer 130.

  Next, as shown in FIG. 11A, the flow path forming substrate wafer 110 is thinned to a certain thickness. Further, for example, 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. 11B, the flow path forming substrate wafer 110 is anisotropically etched (wet etching) using an alkaline solution such as KOH through the mask film 52 to thereby form 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. Then, after removing the silicon dioxide film 51 on the surface opposite to the protective substrate wafer 130 of the flow path forming substrate wafer 110, 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 or the like is divided into the flow path forming substrate 10 or the like having a single chip size 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. More specifically, a SiO ₂ film having a thickness of 1 μm was provided on a silicon substrate. On this SiO ₂ film, Ar pressure at the time of film formation: 0.5 Pa, output power density: 15 kW / m ² , film formation temperature: room temperature (23 ° C., “RT” in the table). ), A Zr layer having a thickness of 270 nm was formed under the condition of the distance (T / S) between the target (Zr) and the SiO ₂ film: 65 mm. The obtained Zr layer had a special crystal region on the surface opposite to the silicon substrate, and was a dense crystal film. Table 1 shows the height of the special crystal region, the size (diameter) and density in plan view, and the (002) plane orientation of the Zr layer.

Thereafter, the Zr layer was thermally oxidized in a diffusion furnace at 900 ° C. to form a ZrO ₂ layer. This ZrO ₂ layer had protrusions having the same height, size and density as the special crystal region of the Zr layer on the surface opposite to the silicon substrate, and was a dense crystal film.

Next, on the ZrO ₂ layer, a Ti film having a thickness of 20 nm, an Ir film having a thickness of 20 nm, a Pt film having a thickness of 60 nm, and an Ir film having a thickness of 20 nm are sequentially formed by sputtering to form the lower electrode film 60. did. The sputtering conditions for each metal film were as follows: Ar pressure at the time of film formation, output power density, and film formation temperature in the order of 0.4 Pa, 9 kW / m ² , room temperature, and 0 for the Ir film on the Ti film. 4 Pa, 30 kW / m ² , room temperature, Pt film was 0.4 Pa, 30 kW / m ² , room temperature, and the Ir film on the Pt film was 0.4 Pa, 30 kW / m ² , room temperature. The obtained lower electrode film had a convex part on the surface opposite to the silicon substrate. Table 3 shows the height and the like of the convex portion of the lower electrode film. As shown in Table 3, even when the special crystal region of the Zr layer was the same, the size of the convex portion of the lower electrode film was different depending on the film formation conditions of the lower electrode film.

  Then, an actuator device was manufactured by providing a 1.1 μm thick piezoelectric layer made of PZT and an upper electrode film 80 made of Ir having a thickness of 50 nm.

(Examples 2 to 6)
About Examples 2-4, except having made the film-forming conditions of each metal film at the time of forming a lower electrode film into the conditions shown in Table 2, and about Examples 5 and 6, An actuator device was produced in the same manner as in Example 1 except that the film formation conditions for forming the Zr layer were the conditions shown in Table 1. The obtained Zr layers of Examples 2 to 6 had a special crystal region on the surface opposite to the silicon substrate, and were dense films. Table 1 shows the height of the special crystal region and the (002) plane orientation degree of the Zr layer. In addition, the ZrO ₂ layer of each of Examples 2 to 6 has a protrusion having the same height, size, and density as the special crystal region of the Zr layer of each of Examples 2 to 6 on the surface opposite to the silicon substrate. In addition, the film was a dense film. And the lower electrode film of each Example 2-6 had a convex part in the surface on the opposite side to a silicon substrate. Table 1 shows the height and the like of the convex portion of the lower electrode film.

(Comparative Examples 1-3)
An actuator device was manufactured in the same manner as in Example 1 except that the film formation conditions for forming the Zr layer were the conditions shown in Table 1. The surface of the obtained Zr film was flat, there was no special crystal region, and the ZrO ₂ layer and the lower electrode film were flat.

(Test Example) Measurement of Adhesion Strength The actuator devices of Examples 1 to 6 and Comparative Examples 1 to 3 were subjected to a scratch test with a scratch apparatus to measure the adhesion force between the SiO ₂ and ZrO ₂ layers. The results are shown in Table 1.

As a result, in Examples 1 to 6 having the ZrO ₂ layer obtained by oxidizing the Zr layer having the special crystal region, the adhesion between the SiO ₂ and the ZrO ₂ layer was good. On the other hand, in Comparative Examples 1 to 3 having a ZrO ₂ layer obtained by oxidizing a Zr layer having no special crystal region, the adhesive strength was remarkably low as compared with Examples 1 to 6. Moreover, since the lower electrode film of Examples 1-6 did not peel from the ZrO ₂ layer during the scratch test, the adhesion between the ZrO ₂ layer of Examples 1-6 and the lower electrode film was good. Was also confirmed.

(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 Embodiment 1 described above, the SiO ₂ layer and the Zr layer are sequentially provided on the substrate. However, a substrate made of a metal oxide may be used, and the Zr layer may be directly provided on the substrate. Examples of the metal of the metal oxide include Mg. With such a configuration, the actuator device is excellent in adhesion between the lower electrode film or substrate and the ZrO ₂ layer. In addition, the board | substrate with which a Zr layer is provided should just be a board | substrate which consists of a metal oxide, for example, you may use the board | substrate with which the metal oxide film is provided in the side by which the Zr layer of a substrate body is provided.

  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.

  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, 80 upper electrode film, 90 lead electrode, 100 reservoir, 300 piezoelectric element, 320 piezoelectric active part, 401 Zr layer, 402 special crystal region, 403 protruding part, 404 convex part

Claims (5)

  SiO formed on the substrate ₂ Layer and said SiO ₂ ZrO formed on the layer ₂ A layer and the ZrO ₂ A lower electrode formed on the layer; a piezoelectric layer formed on the lower electrode; and an upper electrode formed on the piezoelectric layer;
  ZrO ₂ The layer has a protrusion on the surface on the lower electrode side, and the protrusion has a height of 16.0 to 40.6 nm and a size in plan view of 0.3 to 0.5 μm in diameter. ZrO ₂ 1.11 × 10 on the layer ⁷ ~ 1.25 × 10 ⁷ Piece / cm ² Actuator device characterized in that it exists at a density of. The lower electrode has a protrusion protruding from the protrusion of the ZrO ₂ layer on the surface of the piezoelectric layer, and the protrusion has a height of 16.0 to 40.6 nm in plan view. a diameter 0.3~0.5μm size, to claim 1, characterized in that present in a density of the 1.11 × ^{10 7} ~1.25 × ¹⁰ 7 cells on the lower electrode / cm ² The actuator device described.   ZrO ₂ The actuator device according to claim 1, wherein the layer is a columnar crystal and is preferentially oriented in a (−111) plane.   ZrO ₂ The layer is formed by oxidizing the Zr layer, and the protrusion is formed by crystal growth of Zr, has a height of 16.0 to 40.6 nm, and has a diameter in plan view of 0 mm. 1.11 × 10 protruding at 3 to 0.5 μm ⁷ ~ 1.25 × 10 ⁷ Piece / cm ² 4. The actuator device according to claim 1, wherein the special crystal region having a density of 1 is formed by being oxidized. 5. Liquid jet head characterized by including the actuator device according to any one of claims 1 to 4 as a liquid ejection means for ejecting the liquid.