JP2007173690A - Method of manufacturing stacked electrode, actuator device and manufacturing method thereof, and liquid jetting head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a stacked electrode having excellent adhesion performance, an actuator device and manufacturing method thereof, and a liquid jetting head. <P>SOLUTION: The manufacturing method has a process in which an adhesion layer 61 made of an adhesive metal is formed on a substrate 110, an elastic film 50 and an insulation film 55 and a conductor layer 62 is formed on the adhesive layer 61 to form a lower electrode 60 consisting of a stacked electrode, and a piezoelectric layer 70 and an upper electrode 80 are stacked on the lower electrode 60 to form a piezoelectric element 300; and a process in which a predetermined functional film is formed on the substrate by a film forming process for executing pattern formation by wet etching in a state where a surface including an end surface of the adhesive layer is exposed. In this method, prior to the process of forming the functional film, insulation processing is applied to the surface including an end surface of the exposed adhesive layer to form an insulation processing film 63. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a laminated electrode formed on a substrate, an actuator device having a piezoelectric element to which the laminated electrode is applied as an electrode of a piezoelectric element, a method for manufacturing the actuator device, and a liquid ejecting head including the actuator device as a liquid ejecting means. About.

  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 droplets. As such a liquid ejecting head, for example, a piezoelectric element including a lower electrode, a piezoelectric layer, and an upper electrode is provided via a vibration plate on a flow path forming substrate provided with a pressure generation chamber communicating with a nozzle opening. There is also known an ink jet recording head in which a diaphragm is deformed by a piezoelectric element to pressurize ink in a pressure generating chamber and eject ink droplets from nozzle openings.

An ink jet recording head provided with a piezoelectric element includes an adhesion layer formed of an alloy containing a diffusion preventing metal on a zirconium oxide (ZrO ₂ ) layer, a lower electrode formed on the adhesion layer, There has been proposed a head including an electromechanical change element having a piezoelectric layer formed on an electrode and an upper electrode formed on the piezoelectric layer (see, for example, Patent Document 1).

  In such an ink jet recording head, for example, when a metal wiring or an insulating film is formed by a film forming process in which a pattern is formed by wet etching on a piezoelectric element, the end surfaces of the adhesion layer and the lower electrode are exposed. If so, there is a problem that electrolytic corrosion occurs between the adhesion layer and the lower electrode, and the adhesion of the lower electrode is reduced by electrolytic corrosion. Further, if the lower electrode is peeled off from the base, it may cause a head failure or the like, which is not preferable.

  Such a problem exists not only in a piezoelectric element mounted on an ink jet recording head but also in an actuator device having a piezoelectric element, electrode formation of various electronic devices, and the like.

Japanese Patent No. 3517876 (FIG. 9)

  In view of such circumstances, it is an object of the present invention to provide a method for manufacturing a laminated electrode having excellent adhesion, an actuator device, a method for manufacturing the same, and a liquid jet head.

The first aspect of the present invention that solves the above-described problems includes a step of forming an adhesion layer made of an adhesive metal on a substrate and laminating a conductor layer on the adhesion layer to form a laminated electrode, and the adhesion layer Forming a predetermined functional film on the substrate by a film forming process in which pattern formation is performed by wet etching in a state where the surface including the end face is exposed, and before the step of forming the functional film, In the method for manufacturing a laminated electrode, the insulating surface is subjected to an insulating process including the exposed end face of the adhesion layer.
In this first aspect, since the surface including the end face of the exposed adhesion layer is preliminarily insulated before the step of forming the functional film, the gap between the adhesion layer and the conductor layer is formed in the film formation process. Thus, it is possible to reliably prevent the occurrence of electrolytic corrosion, and it is possible to manufacture a laminated electrode having excellent adhesion.

According to a second aspect of the present invention, an adhesive layer made of an adhesive metal is formed on a substrate, a conductor layer is laminated on the adhesive layer to form a lower electrode made of a laminated electrode, and a piezoelectric layer is formed on the lower electrode. A predetermined functional film is formed on the substrate by a step of forming a piezoelectric element by laminating a body layer and an upper electrode, and a film forming process in which a pattern is formed by wet etching with the surface including the end face of the adhesion layer exposed. And a step of insulating the exposed surface including the end face of the adhesion layer before the step of forming the functional film.
In the second aspect, since the surface including the end face of the exposed adhesion layer is preliminarily insulated before the step of forming the functional film, the gap between the adhesion layer and the conductor layer is formed in the film formation process. Thus, it is possible to reliably prevent the occurrence of electrolytic corrosion, and it is possible to manufacture an actuator device having a lower electrode with excellent adhesion.

According to a third aspect of the present invention, in the method for manufacturing an actuator device according to the second aspect, the surface including the end face of the adhesion layer is subjected to an oxidation treatment as an insulation treatment.
In the third aspect, the surface including the end face of the adhesion layer can be satisfactorily insulated by oxidation treatment.

In a fourth aspect of the present invention, the oxidation treatment to the surface including the end face of the adhesion layer is thermal oxidation, the oxidation treatment is performed after the formation of the piezoelectric element, and the surface including the end face of the adhesion layer is thermally oxidized. In the method for manufacturing an actuator device according to the second or third aspect, the heating temperature at the time is set to be equal to or lower than a firing temperature at the time of forming the piezoelectric layer.
In the fourth aspect, the piezoelectric layer can be reliably prevented from being destroyed by the oxidation treatment.

According to a fifth aspect of the present invention, the piezoelectric element having a predetermined shape is formed by patterning the piezoelectric layer formed on the lower electrode and the upper electrode by dry etching. The method of manufacturing an actuator device according to any one of the aspects -4.
In the fifth aspect, since the insulating process is performed in advance on the surface including the end face of the adhesion layer exposed by patterning of the piezoelectric element, electrolytic corrosion occurs between the adhesion layer and the conductor layer in the film forming process. Can be reliably prevented.

In a sixth aspect of the present invention, the functional film is formed of an insulating film made of an inorganic insulating material and covering the piezoelectric element, or a lead electrode made of a metal material and drawn from the piezoelectric element. The method of manufacturing the actuator device according to the fifth aspect.
In the sixth aspect, it is possible to reliably prevent the occurrence of electrolytic corrosion between the adhesion layer and the conductor layer when forming the insulating film or the lead electrode.

According to a seventh aspect of the present invention, in the actuator device according to any one of the second to sixth aspects, the adhesion layer is formed of a material that is difficult to diffuse into the conductor layer during firing to form the piezoelectric layer. It is in the manufacturing method.
In the seventh aspect, the metal component of the adhesion layer is difficult to diffuse into the conductor layer, and the adhesion of the lower electrode can be sufficiently ensured.

According to an eighth aspect of the present invention, the adhesion layer is formed of at least one material selected from the group consisting of Ta, Zr, W, Ni, Hf, Nb, Mo, and Co. It exists in the manufacturing method of the actuator apparatus of any aspect of -7.
In the eighth aspect, a lower electrode having excellent adhesion can be formed.

According to a ninth aspect of the present invention, there is provided a piezoelectric element comprising a lower electrode, a piezoelectric layer, and an upper electrode provided on a substrate, wherein the lower electrode is an adhesive made of an adhesive metal provided on the substrate. And a predetermined functional film formed by a film forming process in which a pattern is formed by wet etching on the substrate. The actuator device is characterized in that an insulating treatment film is provided on a surface including an end face of the adhesion layer exposed in a state before the functional film is formed.
In the ninth aspect, since the lower electrode has excellent adhesion, an actuator device having high reliability can be provided.

According to a tenth aspect of the present invention, there is provided a liquid ejecting head including the actuator device according to the ninth aspect as a liquid ejecting unit that ejects a liquid from a nozzle opening.
In the tenth aspect, a liquid jet head having high reliability can be provided.

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 according to Embodiment 1 of the present invention, FIG. 2 is a plan view of FIG. 1 and a sectional view taken along line AA ′, and FIG. FIG. 3 is an enlarged cross-sectional view of a main part of BB ′ in FIG. As shown in the drawing, the flow path forming substrate 10 is made of a silicon single crystal substrate having a plane orientation (110) in this embodiment, and one surface thereof is made of silicon dioxide previously formed by thermal oxidation. An elastic film 50 of 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. In addition, a communication portion 13 is formed in a region outside the longitudinal direction of the pressure generation chamber 12 of the flow path forming substrate 10, and the communication portion 13 and each pressure generation chamber 12 are provided for each pressure generation chamber 12. Communication is made via a supply path 14. The communication part 13 constitutes a part of a reservoir that communicates with a reservoir part of a protective substrate, which will be described later, and serves as a common ink chamber for the pressure generating chambers 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.

Further, 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 on the opening surface side of the flow path forming substrate 10 will be described later. The mask film 52 is fixed by an adhesive, 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 ) or the like and having a thickness of, for example, about 0.4 μm is laminated. Further, on the insulator film 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, For example, a piezoelectric element 300 including an upper electrode film 80 of about 0.05 μm is formed.

  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, 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. 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, a piezoelectric active part is formed for each pressure generating chamber 12. In the above-described example, the elastic film 50, the insulator film 55, and the lower electrode film 60 function as a diaphragm. However, the present invention is not limited to this, and for example, the elastic film 50 and the insulator film 55 are provided. Instead, only the lower electrode film 60 may act as a diaphragm.

  Further, in the present embodiment, a lead electrode 90 made of, for example, gold (Au) or the like is provided on the upper electrode film 80 of each piezoelectric element 300 as described above. Specifically, a lead electrode 90 is connected to each piezoelectric element 300, and a voltage is selectively applied to each piezoelectric element 300 via each lead electrode 90. As will be described in detail later, the lead electrode 90 is a functional film that is patterned in a predetermined shape by wet etching using an etching solution that is an electrolytic solution and functions as a wiring.

  Furthermore, in this embodiment, the lower electrode film 60 is provided over the parallel arrangement direction of the plurality of piezoelectric elements 300, and the end portion in the longitudinal direction of the pressure generation chamber 12 of the lower electrode film 60 is opposed to the pressure generation chamber 12. It was provided so that it would be a position to do. In addition, the piezoelectric layer 70 extends so as to cover the end of the lower electrode film 60 in the longitudinal direction of the pressure generating chamber 12 and reach the insulator film 55.

  As shown in FIG. 3, the lower electrode film 60 of the piezoelectric element 300 includes an adhesive layer 61 made of an adhesive metal formed on an insulator film 55 made of zirconium oxide, and an adhesive layer 61 on the adhesive layer 61. 2 is a laminated electrode having a two-layer structure composed of a conductor layer 62 formed on the entire surface.

  Here, the adhesive metal that forms the adhesive layer 61 is a refractory metal material that is difficult to diffuse into the conductor layer 62 at the firing temperature when the piezoelectric layer 70 is formed, and a temperature equal to or lower than the firing temperature of the piezoelectric layer 70. It is preferable that the material be thermally oxidized. Specifically, for example, it is preferable to use at least one material selected from the group consisting of Ta, Zr, W, Ni, Hf, Nb, Mo, and Co. As a result, the metal component of the adhesion layer 61 is prevented from diffusing into the conductor layer 62, and sufficient adhesion of the lower electrode film 60 can be ensured. On the other hand, examples of the metal material forming the conductor layer 62 include platinum groups such as platinum (Pt), iridium (Ir), osmium (Os), rhenium (Re), rhodium (Rh), and palladium (Pd). It is done. In the present embodiment, the adhesion layer 61 is made of Zr, and the conductor layer 62 is made of Pt. Of course, the material for forming the adhesion layer 61 and the conductor layer 62 in the present invention is not limited to the materials described above.

  In this embodiment, the lead is formed by a film formation process in which a pattern is formed by film formation and wet etching before the lead electrode 90 having a predetermined shape is formed, that is, after the piezoelectric element 300 is formed for each pressure generation chamber 12. Prior to the step of forming the electrode 90, a predetermined insulating process is performed on the surface (exposed surface) 61a including the end face of the adhesion layer 61 that is exposed at that time, and the insulating process film 63 is provided. .

  More specifically, in the present embodiment, as described above, the lower electrode film 60 is provided over the parallel arrangement direction of the plurality of piezoelectric elements 300, and the piezoelectric layer 70 is formed in the pressure generation chamber 12 of the lower electrode film 60. It extends so as to cover the end in the longitudinal direction and reach the insulator film 55. In such a structure, a part of the end face of the close contact layer 61 (the end face of the region not covered with the piezoelectric layer 70) and the upper surface of the close contact layer 61 corresponding to the region between the adjacent piezoelectric elements 300 are exposed. is doing. In this embodiment, the exposed surface 61a of the adhesion layer 61 thus exposed is subjected to a thermal oxidation treatment as an insulation treatment, and an insulation treatment film 63 made of Zr oxide is provided.

  As described above, in this embodiment, since the insulating treatment film 63 is provided on the surface 61a of the adhesion layer 61 exposed in a state before the lead electrode 90 is formed, the lead electrode 90 will be described in detail later. The etching solution, which is an electrolytic solution used for forming, does not come into direct contact with the conductive adhesion layer 61. For this reason, electrolytic corrosion does not occur between the adhesion layer 61 and the conductor layer 62. Thereby, sufficient adhesion between the insulator film 55 and the lower electrode film 60 can be ensured, head failure can be prevented, and the reliability of the head can be improved.

  The insulating treatment film 63 is preferably a film that is exposed to an etching solution that is an electrolytic solution and does not cause a film thickness reduction in the thickness direction. The insulating treatment film 63 may be formed with such a thickness that the adhesive layer 61 having the property is not exposed to the etching solution.

Examples of the material of the piezoelectric layer 70 formed on the lower electrode film 60 include a ferroelectric piezoelectric material such as lead zirconate titanate (PZT), niobium, nickel, magnesium, bismuth, or yttrium. A relaxor ferroelectric material to which a metal such as the above is added may be used. The composition may be appropriately selected in consideration of the characteristics and application of the piezoelectric element. 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 1/3 Ta 2/3) O ₃ -PbTiO ₃ (PST-PT), Pb (Sc _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PSN-PT), BiScO ₃ -PbTiO ₃ (BS-PT), BiYbO ₃ -PbTiO ₃ ( BY-PT Etc. The. The manufacturing method of the piezoelectric layer 70 is not limited to the sol-gel method, and for example, a MOD (Metal-Organic Decomposition) method may be used.

  Further, on the flow path forming substrate 10 on which the piezoelectric element 300 is formed, that is, on the lower electrode film 60, the insulator film 55, the elastic film 50, and the lead electrode 90, the piezoelectric element is disposed in a region facing the piezoelectric element 300. A protective substrate 30 having a piezoelectric element holding portion 31 having a space that does not hinder the movement of 300 is bonded via an adhesive layer 35. Note that the piezoelectric element holding portion 31 only needs to have a space that does not hinder the movement of the piezoelectric element 300, and the space may be sealed or not sealed.

  Further, the protective substrate 30 is provided with a reservoir portion 32 in a region facing the communication portion 13, and the reservoir portion 32 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 31 and the reservoir portion 32 of the protective substrate 30, and the lower electrode film 60 is provided in the through hole 33. A part of the lead electrode 90 and the leading end of the lead electrode 90 are exposed, and one end of a connection wiring extending from the drive IC is connected to the lower electrode film 60 and the lead electrode 90, although not shown.

  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, a ceramic material, etc. In this embodiment, a single silicon of the same material as the flow path forming substrate 10 is used. 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). The sealing film 41 seals one surface of the reservoir portion 32. 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 sectional views of the pressure generating chamber 12 in the longitudinal direction. 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 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.

  Next, as shown in FIG. 4C, an adhesion layer 61 made of, for example, zirconium (Zr) is formed on the front surface of the insulator film 55, and a conductor layer made of platinum (Pt) is formed on the adhesion layer 61. 62 was formed.

  Next, a piezoelectric layer 70 made of lead zirconate titanate is formed on the lower electrode film 60 in the present embodiment. In this embodiment, a so-called sol-gel method is obtained in which a so-called sol in which a metal organic material is dissolved and dispersed in a catalyst is applied, dried, gelled, and further fired at a high temperature to obtain a piezoelectric layer 70 made of a metal oxide. Was used to form the piezoelectric layer 70. The method for manufacturing the piezoelectric layer 70 is not limited to the sol-gel method, and for example, a MOD (Metal-Organic Decomposition) method or the like may be used.

As an example of a procedure for forming the piezoelectric layer 70, first, as shown in FIG. 5A, a piezoelectric precursor film 71 which is a PZT precursor film is formed on the lower electrode film 60. That is, a sol (solution) containing a metal organic compound is applied onto the flow path forming substrate wafer 110. Next, the piezoelectric precursor film 71 is heated to a predetermined temperature and dried for a predetermined time, and the sol solvent is evaporated to dry the piezoelectric precursor film 71. Further, the piezoelectric precursor film 71 is degreased at a constant temperature for a predetermined time in an air atmosphere. Here, degreasing refers, the organic components of the sol film, for _example, is to be detached as _{NO 2, CO 2, H 2} O or the like.

  Then, as shown in FIG. 5B, the piezoelectric precursor film 71 is crystallized by heat treatment with a diffusion furnace or an RTP (Rapid Thermal Processing) apparatus or the like to form a piezoelectric film 72. That is, by firing the piezoelectric precursor film 71, crystals grow and the piezoelectric film 72 is formed. The firing temperature is preferably 650 to 850 ° C. For example, the piezoelectric precursor film 71 is fired at about 700 ° C. for 30 minutes to form the piezoelectric film 72. The crystal of the piezoelectric film 72 thus formed is preferentially oriented in the (100) plane. Thereafter, the piezoelectric film 72 formed in this way and the lower electrode film 60 as the base are patterned into a predetermined shape.

  Further, by repeating the above-described coating, drying, degreasing, and firing steps a plurality of times, for example, as shown in FIG. 5C, a five-layer piezoelectric film 72 is formed, and a piezoelectric body having a predetermined thickness is formed. Layer 70 is formed. In the case where the piezoelectric layer 70 is formed by firing a plurality of times as described above, the total firing (heating) time is preferably set within 0.5 to 3 hours.

  Next, after the piezoelectric layer 70 is formed in this way, as shown in FIG. 6A, for example, an upper electrode film 80 made of iridium (Ir) is formed on the entire surface of the wafer 110 for flow path formation substrate. To do. Next, as shown in FIG. 6B, the piezoelectric layer 70 and the upper electrode film 80 stacked on the flow path forming substrate wafer 110 are subjected to dry etching such as ion milling or reactive ion etching, for example. Then, the piezoelectric element 300 is formed corresponding to each of the regions to be the pressure generation chambers 12 by patterning the regions to be the pressure generation chambers 12.

  Thus, in the state after patterning the piezoelectric element 300, the end surface of the adhesion layer 61 that is not covered with the piezoelectric element 300 and the upper surface of the adhesion layer 61 corresponding to the region between the adjacent piezoelectric elements 300 are exposed. It becomes a state.

  Next, as shown in FIG. 6C, an insulating process is performed on the surface 61 a including the end face of the adhesion layer 61. Specifically, the insulating treatment film 63 is formed on the surface 61a including the end surface of the adhesion layer 61 exposed after forming the piezoelectric element 300 having a predetermined shape by patterning by dry etching. For example, in this embodiment, the surface 61a including the end face of the adhesion layer 61 is thermally oxidized by heating at about 650 ° C. for 5 minutes in an oxygen atmosphere to form the insulating treatment film 63 made of Zr oxide. Since the upper electrode film 80 is made of Ir, it is hardly oxidized by the heat treatment here. That is, according to the above thermal oxidation conditions, only the exposed surface 61a of the adhesion layer 61 can be selectively thermally oxidized.

  Here, the condition for thermally oxidizing the surface 61a of the adhesion layer 61 is preferably set to a firing temperature or lower, specifically about 850 ° C. or lower when the piezoelectric layer 70 is formed. In this embodiment, since the firing temperature at the time of forming the piezoelectric layer 70 is 700 ° C., it is set to 700 ° C. or lower. This is to prevent the piezoelectric layer 70 from being destroyed by heat when the insulating treatment film 63 is formed. In this embodiment, the surface 61a of the adhesion layer 61 is thermally oxidized to form the insulating treatment film 63. However, the present invention is of course not limited to this, and an insulating treatment film such as anodization is formed. May be. The insulating treatment film 63 is a film having an insulating property that can reliably block conduction between the adhesion layer 61 and the conductor layer 62 even when exposed to an etching solution (electrolytic solution) in a film forming process described later. Is formed.

  Next, the lead electrode 90 is formed. Specifically, as shown in FIG. 7A, a metal layer 91 made of, for example, gold (Au) or the like is formed over the entire surface of the flow path forming substrate wafer 110. Thereafter, a mask pattern (not shown) made of, for example, a resist is formed on the metal layer 91, and the metal layer 91 is wet-etched with an etching solution made of a predetermined electrolytic solution through this mask pattern to form each piezoelectric layer. Patterning is performed for each element 300. Thereafter, the lead electrode 90 is formed by removing the mask pattern. The lead electrode 90 may be a laminated electrode having a two-layer structure including an adhesion layer and a conductor layer formed on the adhesion layer.

  Here, in this embodiment, since the insulating treatment film 63 is formed on the surface of the adhesion layer 61 in advance, the etching solution that is an electrolytic solution used when forming the lead electrode 90 is used as the insulation treatment film of the adhesion layer 61. 63, but does not contact the conductive adhesion layer 61. For this reason, it is possible to reliably prevent electrolytic corrosion between the adhesion layer 61 and the conductor layer 62. Thereby, sufficient adhesion between the insulator film 55 and the lower electrode film 60 can be secured, and the lower electrode film 60 is not peeled off after the lead electrode 90 is formed. Therefore, the lower electrode film 60 and the piezoelectric element 300 having excellent adhesion can be formed, the head failure can be prevented, and the reliability of the head can be improved.

  Next, as shown in FIG. 7B, a protective substrate wafer that is a silicon wafer and serves as a plurality of protective substrates 30 via an adhesive layer 35 on the piezoelectric element 300 side of the flow path forming substrate wafer 110. 130 is joined. 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.

  Next, as shown in FIG. 7C, after the flow path forming substrate wafer 110 is polished to a certain thickness, the flow path forming substrate wafer 110 is further etched to a predetermined thickness by wet etching with hydrofluoric acid. To. For example, in this embodiment, the flow path forming substrate wafer 110 is etched so as to have a thickness of about 70 μm.

  Next, as shown in FIG. 8A, a mask film 52 made of, for example, silicon nitride (SiN) is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, the flow path forming substrate wafer 110 is anisotropically etched through the mask film 52, whereby, as shown in FIG. 13 and the ink supply path 14 are formed.

  After that, 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 the flow path forming substrate 10 and the like of one chip size as shown in FIG. 1, the ink jet recording head of this embodiment is obtained.

(Other embodiments)
As mentioned above, although this invention was demonstrated based on one Embodiment, this invention is not limited to one Embodiment mentioned above. For example, in the above-described embodiment, the head structure in which the lower electrode film 60 is continuously provided in the parallel arrangement direction of the piezoelectric elements 300 has been described. However, the present invention is not limited to this, and for example, as shown in FIG. In addition, a piezoelectric element 300A in which a lower electrode film 60A, a piezoelectric layer 70, and an upper electrode film 80 are laminated is provided in a region facing each pressure generating chamber 12, and a piezoelectric element is provided in a region facing each pressure generating chamber 12. The present invention can also be applied to a head structure in which the lower electrode film 60A is discontinuous in the parallel arrangement direction of 300A. In this case, before the lead electrode 90 having a predetermined shape is formed, that is, after the piezoelectric element 300A is formed for each pressure generation chamber 12, the lead electrode 90 is formed by a film formation process in which a pattern is formed by film formation and wet etching. Before the step of forming the insulating film 63A, an insulating treatment film 63A is provided on the end face of the adhesion layer 61A of the lower electrode film 60A exposed on both sides of the piezoelectric element 300A in the width direction. As a result, as in the above-described embodiment, since the electrolytic corrosion does not occur between the adhesion layer 61A and the conductor layer 62A when the lead electrode 90 is formed, the adhesion between the lower electrode film 60A and the piezoelectric element 300A. Can be secured sufficiently. FIG. 9 is an enlarged cross-sectional view of a main part in the width direction of a piezoelectric element according to another embodiment of the present invention.

  In the above-described embodiment, the lower electrode film 60 is taken as an example of a laminated electrode and the lead electrode 90 is exemplified as a functional film. However, the present invention is not limited to this, and the present invention is not limited to this. The present invention can also be applied to the case where a protective film made of alumina or the like is formed by patterning by wet etching of an electrolytic solution after forming a lead electrode made of a layer. In addition, when forming a protective film made of alumina or the like so as to cover the piezoelectric element after forming the piezoelectric element and before forming the lead electrode, it is exposed before forming the protective film. Insulating treatment may be performed on the surface including the end face of the adhesion layer. In such a case, the protective film basically covers each layer constituting the piezoelectric element, but a contact hole is formed in the protective film in a region facing one end portion of the piezoelectric element. The lead electrode and the piezoelectric element (upper electrode film) are electrically connected through this contact hole.

  In the above-described embodiment, the insulating treatment film 63 is formed by oxidation treatment. However, the present invention is of course not limited to this. For example, after the piezoelectric element is formed and before the predetermined film formation process is performed, the insulating film 63 is adhered. An insulating material may be selectively supplied to the end face of the layer to form an insulating treatment film.

  In the above-described embodiment, the conductor layer 62 is provided on the entire surface of the adhesion layer 61. However, for example, the pattern shape of the adhesion layer may be larger than the pattern shape of the conductor layer, or may be smaller. Also good.

  In the above-described embodiment, the ink jet recording head has been described as an example of the liquid ejecting head. However, the present invention is widely applied to all liquid ejecting heads, and 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 (surface emitting 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 can be applied not only to an actuator device mounted as liquid ejecting means on such a liquid jet head (inkjet recording head) but also to an actuator device mounted on any device. For example, the actuator device can be applied to a sensor or the like in addition to the head described above.

  Furthermore, the present invention is applicable to a method for manufacturing a piezoelectric element used for a liquid ejecting head, and is mounted not only on the piezoelectric element of the head but also on, for example, a microphone, a sounding body, various vibrators, an oscillator, and the like. Is also applicable.

  In any case, the present invention is not limited to the above-described one, and prior to the film forming process of forming a pattern by wet etching of the electrolytic solution, so as not to cause electrolytic corrosion between the adhesion layer and the conductor layer. By positively insulating the surface including the end face of the exposed adhesion layer, the unique effect of sufficiently ensuring the adhesion between the laminated electrode composed of the adhesion layer and the conductor layer and the underlying layer can be obtained. Play.

  Therefore, in the present invention, after forming a laminated electrode by laminating an adhesion layer and a conductor layer on a substrate, pattern formation is performed by wet etching using an electrolytic solution in a state where the surface including the end face of the adhesion layer is exposed. Before forming a predetermined functional film on a substrate by a film forming process, it can be widely applied as a method of manufacturing a laminated electrode having a step of performing an insulation treatment on the surface including the end face of the adhesion layer exposed in that state. .

1 is an exploded perspective view showing a schematic configuration of a recording head according to an embodiment of the present invention. 2A and 2B are a plan view and a cross-sectional view of a recording head according to an embodiment of the invention. FIG. 3 is an enlarged cross-sectional view of a main part of a recording head according to an embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating a recording head manufacturing method according to an embodiment of the invention. FIG. 6 is a cross-sectional view illustrating a recording head manufacturing method according to an embodiment of the invention. FIG. 6 is a cross-sectional view illustrating a recording head manufacturing method according to an embodiment of the invention. FIG. 6 is a cross-sectional view illustrating a recording head manufacturing method according to an embodiment of the invention. FIG. 6 is a cross-sectional view illustrating a recording head manufacturing method according to an embodiment of the invention. FIG. 5 is an enlarged cross-sectional view of a main part of a recording head according to another embodiment of the present invention.

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 Piezoelectric element holding part, 32 Reservoir part, 40 Compliance board, 60 Lower electrode film , 61 Adhesion layer, 62 Conductor layer, 63 Insulation treatment film, 70 Piezoelectric layer, 80 Upper electrode film, 90 Lead electrode, 100 Reservoir, 300 Piezoelectric element

Claims (10)

Forming an adhesion layer made of an adhesion metal on the substrate and laminating a conductor layer on the adhesion layer to form a laminated electrode, and a pattern by wet etching with the surface including the end face of the adhesion layer exposed Forming a predetermined functional film on the substrate by a film forming process for forming, and before the step of forming the functional film, an insulating process is performed on the exposed surface including the end face of the adhesion layer The manufacturing method of the laminated electrode characterized by performing these. An adhesion layer made of an adhesive metal is formed on the substrate, a conductor layer is laminated on the adhesion layer to form a lower electrode made of a laminated electrode, and a piezoelectric layer and an upper electrode are laminated on the lower electrode. A step of forming a piezoelectric element, and a step of forming a predetermined functional film on the substrate by a film forming process of performing pattern formation by wet etching in a state where a surface including an end face of the adhesion layer is exposed, Before the step of forming the functional film, an insulating process is performed on the exposed surface including the end face of the adhesion layer. The method for manufacturing an actuator device according to claim 2, wherein an oxidation treatment is performed as an insulation treatment on a surface including an end face of the adhesion layer. The oxidation treatment to the surface including the end face of the adhesion layer is thermal oxidation, the heating treatment is performed after the formation of the piezoelectric element and the surface including the end face of the adhesion layer is thermally oxidized. The method for manufacturing an actuator device according to claim 2, wherein the temperature is equal to or lower than a firing temperature at the time of formation of the actuator device. 5. The piezoelectric element having a predetermined shape is formed by patterning the piezoelectric layer formed on the lower electrode and the upper electrode by dry etching. 6. Manufacturing method of actuator device. 6. The method of manufacturing an actuator device according to claim 5, wherein an insulating film made of an inorganic insulating material and covering the piezoelectric element is formed as the functional film, or a lead electrode made of a metal material and drawn from the piezoelectric element is formed. . The method for manufacturing an actuator device according to claim 2, wherein the adhesion layer is formed of a material that is difficult to diffuse into the conductor layer during firing to form the piezoelectric layer. The adhesion layer is formed of at least one material selected from the group consisting of Ta, Zr, W, Ni, Hf, Nb, Mo, and Co. Manufacturing method of actuator device. A piezoelectric element comprising a lower electrode, a piezoelectric layer, and an upper electrode provided on a substrate is provided, and the lower electrode is provided on an adhesion layer made of an adhesive metal provided on the substrate and the adhesion layer. A predetermined functional film formed by a film forming process for forming a pattern by wet etching is provided on the substrate, and is formed on the substrate before the functional film is formed. An actuator device characterized in that an insulating treatment film is provided on a surface including an end face of the adhesion layer exposed in the state of (1). A liquid ejecting head comprising the actuator device according to claim 9 as liquid ejecting means for ejecting liquid from a nozzle opening.

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