Inkjet printhead and method of manufacturing same

Abstract

This inkjet print head comprises: a piezoelectric element including a lower electrode arranged on a movable film, a piezoelectric film formed on the lower electrode, and an upper electrode formed on the piezoelectric film; a hydrogen barrier film covering at least an entire region of lateral surfaces of the upper electrode, the piezoelectric film, and the lower electrode, at least a part of an upper surface of the upper electrode, and an upper surface of the lower electrode in a surface of the piezoelectric element; a first interlayer insulation film formed on a surface other than an end surface of the hydrogen barrier film; a second interlayer insulation film formed so as to cover the end surface of the hydrogen barrier film and the first interlayer insulation film; and wiring formed on the second interlayer insulation film and connected to the piezoelectric element.

Description

[Technical field]

[0001] The present disclosure relates to inkjet printheads and methods of manufacturing the same. [Background technology]

[0002] Patent Document 1 discloses an inkjet printhead. The inkjet printhead of Patent Document 1 includes an actuator substrate (substrate) having a pressure chamber (pressure generating chamber) as an ink flow path, a movable membrane (elastic membrane) formed on the actuator substrate, and a piezoelectric element provided on the movable membrane. The inkjet printhead of Patent Document 1 further includes a nozzle substrate (nozzle plate) bonded to the lower surface of the actuator substrate and having a nozzle opening (nozzle hole) communicating with the pressure chamber, and a protective substrate bonded to the upper surface of the actuator substrate and covering the piezoelectric element. The piezoelectric element is composed of a first electrode film (lower electrode) formed on the movable membrane, a second electrode film (upper electrode) arranged on the first electrode film, and a piezoelectric layer (piezoelectric film) sandwiched between them. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-91668 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide an inkjet printhead and a manufacturing method thereof in which wiring is less susceptible to deterioration even when a hydrogen barrier film is corroded by ink. [Means for solving the problem]

[0005] One embodiment of the present disclosure provides an inkjet printhead including an actuator substrate having an ink flow path including a pressure chamber; a movable film forming layer including a movable film disposed over the pressure chamber and defining a ceiling portion of the pressure chamber; a piezoelectric element including a lower electrode disposed on the movable film, a piezoelectric film formed on the lower electrode, and an upper electrode formed on the piezoelectric film; a hydrogen barrier film covering at least the entire side surfaces of the upper electrode, the piezoelectric film, and the lower electrode, at least a portion of the upper surface of the upper electrode, and the upper surface of the lower electrode, of the surface of the piezoelectric element; a first interlayer insulating film formed on a surface of the hydrogen barrier film excluding an end face; a second interlayer insulating film formed so as to cover the end face of the hydrogen barrier film and the first interlayer insulating film; and wiring formed on the second interlayer insulating film and connected to the piezoelectric element.

[0006] In this configuration, the end faces of the hydrogen barrier film do not come into contact with the wiring, so that even if the hydrogen barrier film is corroded by ink, the wiring is less likely to deteriorate.

[0007] One embodiment of the present disclosure provides a method for manufacturing an inkjet printhead, the method including the steps of: forming a first hydrogen barrier material film, a bottom electrode film, a piezoelectric material film, and an top electrode film on a substrate in this order; patterning the top electrode film and the piezoelectric material film into an top electrode pattern to form an top electrode and a piezoelectric film; patterning the bottom electrode film and the first hydrogen barrier material film into a bottom electrode pattern to form a bottom electrode and a first hydrogen barrier film; forming a second hydrogen barrier material film covering the entire surface of the substrate, and then forming a first interlayer insulating material film on the entire surface of the second hydrogen barrier material film; patterning the second hydrogen barrier material film and the first interlayer insulating material film into a predetermined second hydrogen barrier film pattern to form a second hydrogen barrier film and a first interlayer insulating film; forming a second interlayer insulating film covering the second hydrogen barrier film and the first interlayer insulating film on the substrate;

[0008] The above and other objects, features and advantages of the present invention will become apparent from the following detailed description of the embodiments with reference to the accompanying drawings. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic plan view for explaining the configuration of an inkjet printhead according to an embodiment of the first disclosure. [Diagram 2] FIG. 2 is a schematic plan view for explaining the configuration of an inkjet printhead according to an embodiment of the first present disclosure, in which a protection substrate is omitted. [Diagram 3] FIG. 3 is a schematic partially enlarged plan view showing a portion A in FIG. [Figure 4] FIG. 4 is a schematic partially enlarged plan view showing an enlarged A portion of FIG. 1, with the protection substrate omitted. [Diagram 5] FIG. 5 is a schematic cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is a schematic partially enlarged plan view showing a portion B in FIG. [Figure 7] FIG. 7 is a schematic enlarged partial sectional view showing a portion C in FIG. [Figure 8] FIG. 8 is a schematic cross-sectional view taken along line VIII-VIII in FIG. [Figure 9] FIG. 9 is a schematic cross-sectional view taken along line IX-IX in FIG. [Figure 10] FIG. 10 is a schematic plan view showing an example of a pattern of an interlayer insulating film of the inkjet print head. [Figure 11] FIG. 11 is a schematic plan view showing an example of a pattern of a passivation film of the inkjet print head. [Figure 12A] FIG. 11A is a cross-sectional view showing an example of a manufacturing process of the inkjet printhead. [Figure 12B] FIG. 12B is a cross-sectional view showing the next step of FIG. 12A. [Figure 12C] FIG. 12C is a cross-sectional view showing the next step of FIG. 12B. [Figure 12D] FIG. 12D is a cross-sectional view showing the next step of FIG. 12C. [Figure 12E] FIG. 12E is a cross-sectional view showing the next step of FIG. 12D. [Figure 12F] FIG. 12F is a cross-sectional view showing the step following that of FIG. 12E. [Figure 12G] FIG. 12G is a cross-sectional view showing the next step after FIG. 12F. [Figure 12H] FIG. 12H is a cross-sectional view showing the step following that of FIG. 12G. [Figure 12I] FIG. 12I is a cross-sectional view showing the step following that of FIG. 12H. [Figure 12J] FIG. 12J is a cross-sectional view showing the step following that of FIG. 12I. [Figure 12K] FIG. 12K is a cross-sectional view showing the step following that of FIG. 12J. [Figure 12L] FIG. 12L is a cross-sectional view showing the step following that of FIG. 12K. [Figure 12M] FIG. 12M is a cross-sectional view showing the next step of FIG. 12L. [Figure 12N] FIG. 12N is a cross-sectional view showing the next step of FIG. 12M. [Figure 12O] FIG. 12O is a cross-sectional view showing the step following that of FIG. 12N. [Figure 12P] FIG. 12P is a cross-sectional view showing the next step of FIG. 12O. [Figure 12Q] FIG. 12Q is a cross-sectional view showing the step following that of FIG. 12P. [Figure 12R] FIG. 12R is a cross-sectional view showing the step following that of FIG. 12Q. [Figure 12S] FIG. 12S is a cross-sectional view showing the step following that of FIG. 12R. [Figure 12T] FIG. 12T is a cross-sectional view showing the step following that of FIG. 12S. [Figure 12U] FIG. 12U is a cross-sectional view showing the step following that of FIG. 12T. [Figure 12V]FIG. 12V is a cross-sectional view showing the next step of FIG. 12U. [Figure 12W] FIG. 12W is a cross-sectional view showing the next step of FIG. 12V. [Fig. 12X] FIG. 12X is a cross-sectional view showing the next step of FIG. 12W. [Figure 12Y] FIG. 12Y is a cross-sectional view showing the next step of FIG. 12X. [Figure 12Z1] FIG. 12Z1 is a cross-sectional view showing the step following that of FIG. 12Y. [Figure 12Z2] FIG. 12Z2 is a cross-sectional view showing the step subsequent to that of FIG. 12Z1. [Figure 12Z3] FIG. 12Z3 is a cross-sectional view showing the step subsequent to that of FIG. 12Z2. [Figure 12Z4] FIG. 12Z4 is a cross-sectional view showing the next step of FIG. 12Z3. [Figure 12Z5] FIG. 12Z5 is a cross-sectional view showing the next step of FIG. 12Z4. [Figure 13] FIG. 13 is a plan view showing a semiconductor wafer as an original substrate for the actuator substrate. [Figure 14A] FIG. 14A is a cross-sectional view showing a part of a manufacturing process of a comparative example. [Figure 14B] FIG. 14B is a cross-sectional view showing the next step of FIG. 14A. [Figure 14C] FIG. 14C is a cross-sectional view showing the step subsequent to that of FIG. 14B. [Figure 14D] FIG. 14D is a cross-sectional view showing the next step of FIG. 14C. [Figure 15] FIG. 15 is a schematic enlarged partial cross-sectional view showing a portion D in FIG. 14D. [Figure 16] FIG. 16 is a schematic plan view for explaining the configuration of an inkjet printhead according to an embodiment of the fourth present disclosure. [Figure 17] FIG. 17 is a schematic partially enlarged plan view showing an enlarged A portion of FIG. 16, and is a plan view including a protection substrate. [Figure 18]FIG. 18 is a schematic partially enlarged plan view showing an enlarged portion A of FIG. 16, in which the protective substrate is omitted. [Figure 19] FIG. 19 is a schematic cross-sectional view taken along line XIX-XIX in FIG. [Figure 20] FIG. 20 is an enlarged cross-sectional view showing the nozzle hole of FIG. [Figure 21] FIG. 21 is a plan view taken along the line indicated by arrows XXI-XXI in FIG. [Figure 22] FIG. 22 is a schematic cross-sectional view taken along line XXII-XXII in FIG. [Figure 23] FIG. 23 is a schematic cross-sectional view taken along line XXIII-XXIII in FIG. [Figure 24] FIG. 24 is a schematic cross-sectional view taken along line XXIV-XXIV in FIG. [Diagram 25] FIG. 25 is a schematic plan view showing an example of a pattern of an insulating film of the ink-jet print head, and corresponds to FIG. [Figure 26] FIG. 26 is a schematic plan view showing an example of a pattern of a passivation film of the ink-jet print head, and corresponds to FIG. 17. In FIG. [Figure 27] FIG. 27 is a bottom view of the area of ​​the protection substrate shown in FIG. [Figure 28] FIG. 28 is a plan view of a semiconductor wafer serving as an original substrate for the actuator substrate. [Figure 29A] FIG. 29A is a cross-sectional view showing an example of a manufacturing process of the inkjet printhead. [Figure 29B] FIG. 29B is a cross-sectional view showing the next step of FIG. 29A. [Figure 29C] FIG. 29C is a cross-sectional view showing the next step of FIG. 29B. [Figure 29D] FIG. 29D is a cross-sectional view showing the next step of FIG. 29C. [Figure 29E] FIG. 29E is a cross-sectional view showing the next step of FIG. 29D. [Figure 29F]FIG. 29F is a cross-sectional view showing the step following that of FIG. 29E. [Figure 29G] FIG. 29G is a cross-sectional view showing the step following that of FIG. 29F. [Figure 29H] FIG. 29H is a cross-sectional view showing the step following that of FIG. 29G. [Figure 29I] FIG. 29I is a cross-sectional view showing the step following that of FIG. 29H. [Figure 29J] FIG. 29J is a cross-sectional view showing the step following that of FIG. 29I. [Figure 29K] FIG. 29K is a cross-sectional view showing the step following that of FIG. 29J. [Figure 29L] FIG. 29L is a cross-sectional view showing the step following that of FIG. 29K. [Figure 29M] FIG. 29M is a cross-sectional view showing the step following that of FIG. 29L. [Figure 30A] FIG. 30A is a cross-sectional view that typically shows a manufacturing process for a nozzle substrate assembly. [Figure 30B] FIG. 30B is a cross-sectional view showing the next step of FIG. 30A. [Figure 30C] FIG. 30C is a cross-sectional view showing the step subsequent to that of FIG. 30B. [Figure 30D] FIG. 30D is a cross-sectional view showing the step following that of FIG. 30C. [Figure 30E] FIG. 30E is a cross-sectional view showing the step following that of FIG. 30D. [Diagram 31] FIG. 31 is a cross-sectional view showing a modified example of the recess of the nozzle hole. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [1] First, About This Disclosure [Description of the First Embodiment of the Present Disclosure] A first embodiment of the present disclosure provides an inkjet printhead including an actuator substrate having an ink flow path including a pressure chamber; a movable film forming layer including a movable film arranged over the pressure chamber and defining a ceiling portion of the pressure chamber; a piezoelectric element including a lower electrode arranged on the movable film, a piezoelectric film formed on the lower electrode, and an upper electrode formed on the piezoelectric film; a hydrogen barrier film covering at least the entire side surfaces of the upper electrode, the piezoelectric film, and the lower electrode, at least a portion of the upper surface of the upper electrode, and the upper surface of the lower electrode, of the surface of the piezoelectric element; a first interlayer insulating film formed on a surface of the hydrogen barrier film excluding an end face; a second interlayer insulating film formed so as to cover the end face of the hydrogen barrier film and the first interlayer insulating film; and wiring formed on the second interlayer insulating film and connected to the piezoelectric element.

[0011] In this configuration, the end faces of the hydrogen barrier film do not come into contact with the wiring, so that even if the hydrogen barrier film is corroded by ink, the wiring is less likely to deteriorate.

[0012] In the first embodiment of the present disclosure, the lower electrode includes a main electrode portion in contact with the lower surface of the piezoelectric film, and an extension portion extending from the main electrode portion outwardly of the piezoelectric film.

[0013] In a first embodiment of the present disclosure, the wiring includes an upper wiring connected to the upper electrode and a lower wiring connected to the lower electrode.

[0014] In a first embodiment of the present disclosure, an upper contact hole exposing a portion of the upper surface of the upper electrode is formed in the hydrogen barrier film, the first interlayer insulating film, and the second interlayer insulating film formed on the upper surface of the upper electrode, one end of the upper wiring is connected to the upper electrode via the upper contact hole, a lower contact hole exposing a portion of the upper surface of the lower electrode is formed in the hydrogen barrier film, the first interlayer insulating film, and the second interlayer insulating film formed on the upper surface of the lower electrode, and one end of the lower wiring is connected to the lower electrode via the lower contact hole.

[0015] In the first embodiment of the present disclosure, the hydrogen barrier film is also formed on the lower surface of the lower electrode.

[0016] In one embodiment of the first disclosure, the semiconductor device further includes a passivation film formed on the second interlayer insulating film and covering the wiring.

[0017] In a first embodiment of the present disclosure, in a planar view seen from a direction normal to the main surface of the movable membrane, the top surface of the pressure chamber has a rectangular shape that is elongated in a predetermined first direction, and the upper electrode and the piezoelectric film have a rectangular shape that is elongated in the first direction and have a periphery that is recessed further inward into the pressure chamber than the movable membrane.

[0018] In a first embodiment of the present disclosure, the lower electrode has a rectangular shape that is long in the first direction when viewed in the plan view, the longitudinal length of the lower electrode is longer than the longitudinal length of the piezoelectric film and shorter than the longitudinal length of the movable film, both end edges of the lower electrode are arranged with a space inward from the corresponding end edges of the movable film, the lateral length of the lower electrode is longer than the lateral length of the piezoelectric film and longer than the lateral length of the movable film, and both side edges of the lower electrode are arranged with a space outward from the corresponding side edges of the movable film.

[0019] In a first embodiment of the present disclosure, a plurality of pressure chambers are provided, a piezoelectric element is provided for each pressure chamber, and the actuator substrate is formed with a plurality of pressure chamber rows spaced apart in the first direction, the pressure chambers being spaced apart in a second direction perpendicular to the first direction when viewed in the plan view.

[0020] A first embodiment of the present disclosure includes a nozzle substrate bonded to a surface of the actuator substrate opposite the surface on the movable membrane side, the nozzle substrate defining a bottom portion of the pressure chamber and having a nozzle hole communicating with the pressure chamber, and a protective substrate disposed on the opposite side of the actuator substrate from the nozzle substrate and bonded to the actuator substrate so as to cover the piezoelectric element, the protective substrate having an accommodating recess that opens toward the actuator substrate and accommodates the piezoelectric element, and an ink passage communicating with the ink flow path.

[0021] A first embodiment of the present disclosure provides a method for manufacturing an inkjet printhead, the method including the steps of: forming a first hydrogen barrier material film, a lower electrode film, a piezoelectric material film, and an upper electrode film on a substrate in this order; patterning the upper electrode film and the piezoelectric material film into an upper electrode pattern to form an upper electrode and a piezoelectric film; patterning the lower electrode film and the first hydrogen barrier material film into a lower electrode pattern to form a lower electrode and a first hydrogen barrier film; forming a second hydrogen barrier material film covering the entire surface of the substrate, and then forming a first interlayer insulating material film on the entire surface of the second hydrogen barrier material film; patterning the second hydrogen barrier material film and the first interlayer insulating material film into a predetermined second hydrogen barrier film pattern to form a second hydrogen barrier film and a first interlayer insulating film; forming a second interlayer insulating film covering the second hydrogen barrier film and the first interlayer insulating film on the substrate; and forming an upper wiring, one end of which is connected to the upper electrode, and a lower wiring, one end of which is connected to the lower electrode, on the second interlayer insulating film.

[0022] In a first embodiment of the present disclosure, the wiring formation process includes a process of forming an upper contact hole exposing a portion of the upper surface of the upper electrode and a lower contact hole exposing a portion of the upper surface of the lower electrode, which are contact holes that continuously penetrate the second interlayer insulating film, the first interlayer insulating film, and the second hydrogen barrier film, a process of forming a wiring film on the second interlayer insulating film including within the upper contact hole and the lower contact hole, and a process of forming the upper wiring and the lower wiring by patterning the wiring film.

[0023] In a first embodiment of the present disclosure, the method includes, after the wiring forming step, a step of forming a passivation film on a surface of the second interlayer insulating film to cover the upper wiring and the lower wiring. [Detailed Description of the First Embodiment of the Present Disclosure] The first embodiment of the present disclosure will be described in detail below with reference to FIGS.

[0024] Fig. 1 is a schematic plan view for explaining the configuration of an inkjet printhead according to an embodiment of the first present disclosure. Fig. 2 is a schematic plan view for explaining the configuration of an inkjet printhead according to an embodiment of the first present disclosure, where a protective substrate is omitted. Fig. 3 is a schematic partial enlarged plan view showing an enlargement of a portion A in Fig. 1. Fig. 4 is a schematic partial enlarged plan view showing an enlargement of a portion A in Fig. 1, where a protective substrate is omitted.

[0025] Fig. 5 is a schematic cross-sectional view taken along line VV in Fig. 3. Fig. 6 is a schematic partially enlarged plan view showing an enlargement of part B in Fig. 5. Fig. 7 is a schematic partially enlarged cross-sectional view showing an enlargement of part C in Fig. 6. Fig. 8 is a schematic cross-sectional view taken along line VIII-VIII in Fig. 1. Fig. 9 is a schematic cross-sectional view taken along line IX-IX in Fig. 3.

[0026] The configuration of the inkjet printhead 1 will be roughly described with reference to FIGS.

[0027] The inkjet printhead 1 comprises a substrate assembly SA including an actuator substrate 2 and a piezoelectric element 10 , a nozzle substrate 3 , and a protection substrate 4 .

[0028] The actuator substrate 2 is made of, for example, a silicon (Si) substrate. In this embodiment, the thickness of the actuator substrate 2 is about 70 μm. A movable film formation layer 5 is laminated on a surface 2a of the actuator substrate 2. An ink flow path 6 through which ink is circulated is formed in the actuator substrate 2. In this embodiment, the ink flow path 6 is formed penetrating the actuator substrate 2. The ink flow path 6 is formed to extend in an elongated manner along an ink flow direction 50 indicated by an arrow in FIG. 5.

[0029] The ink flow path 6 is composed of an ink inflow section 7, a pressure chamber 8, and an ink outflow section 9. The ink inflow section 7 is disposed at the upstream end (the left end in FIG. 5) of the ink flow direction 50, and the ink outflow section 9 is disposed at the downstream end (the right end in FIG. 5) of the ink flow direction 50. The pressure chamber 8 is disposed between the ink inflow section 7 and the ink outflow section 9, and is connected to the ink inflow section 7 and the ink outflow section 9. In FIG. 5, the boundary between the ink inflow section 7 and the pressure chamber 8 and the boundary between the pressure chamber 8 and the ink outflow section 9 are indicated by dashed dotted lines.

[0030] The nozzle substrate 3 is made of, for example, a silicon (Si) substrate. In this embodiment, the thickness of the nozzle substrate 3 is about 50 μm. The nozzle substrate 3 is attached to the rear surface 2b of the actuator substrate 2 via an adhesive layer 63. The nozzle substrate 3 defines an ink flow path 6 together with the actuator substrate 2 and the movable film formation layer 5. More specifically, the nozzle substrate 3 defines the bottom portion of the ink flow path 6.

[0031] The nozzle substrate 3 is formed with a nozzle hole 3a that communicates with the pressure chamber 8. The nozzle hole 3a penetrates the nozzle substrate 3 and has an ink ejection port 3b on the opposite side to the pressure chamber 8. When a change in the volume of the pressure chamber 8 occurs, the ink in the pressure chamber 8 passes through the nozzle hole 3a and is ejected from the ink ejection port 3b.

[0032] The ceiling wall of the ink flow path 6 in the movable film formation layer 5 constitutes the movable film 5A. The movable film 5A (movable film formation layer 5) is, for example, a silicon oxide (SiO 2 The movable film 5A (movable film formation layer 5) is made of, for example, a silicon (Si) film formed on the actuator substrate 2 and a silicon oxide (SiO 2 The movable film 5A may be a laminated film of a silicon oxide film and a silicon nitride (SiN) film formed on a silicon oxide film. In this specification, the movable film 5A means a ceiling wall portion of the movable film forming layer 5 that defines the ceiling portion of the pressure chamber 8. Therefore, the portion of the movable film forming layer 5 other than the ceiling wall portion of the pressure chamber 8 does not constitute the movable film 5A.

[0033] The thickness of the movable film 5A is, for example, about 0.4 μm to 2 μm. When the movable film 5A is made of a silicon oxide film, the thickness of the silicon oxide film may be about 1.5 μm. When the movable film 5A is made of a laminated film of a silicon oxide film and a silicon nitride film, the thickness of the silicon oxide film and the silicon nitride film may each be about 0.7 μm.

[0034] The pressure chamber 8 is defined by the movable film 5A, the actuator substrate 2, and the nozzle substrate 3, and in this embodiment, is formed in a substantially rectangular parallelepiped shape. The length of the pressure chamber 8 is, for example, about 700 μm, and its width is, for example, about 54 μm. The ink inflow section 7 communicates with one end of the pressure chamber 8 in the longitudinal direction, and the ink outflow section 9 communicates with the other end of the pressure chamber 8 in the longitudinal direction.

[0035] A first hydrogen barrier film 21 is formed on the surface of the movable film 5A. The first hydrogen barrier film 21 is made of, for example, Al 2 O 3(alumina). The first hydrogen barrier film 21 has a thickness of about 50 nm to 100 nm. In this embodiment, the first hydrogen barrier film 21 has a thickness of about 80 nm. On the surface of the first hydrogen barrier film 21, a piezoelectric element 10 is disposed above the movable film 5A. The piezoelectric element 10 includes a lower electrode 11 formed on the first hydrogen barrier film 21, a piezoelectric film 12 formed on the lower electrode 11, and an upper electrode 13 formed on the piezoelectric film 12. In other words, the piezoelectric element 10 is configured by sandwiching the piezoelectric film 12 between the upper electrode 13 and the lower electrode 11 from above and below. The piezoelectric element 10 has a rectangular shape that is elongated in the ink flow direction 50 in a plan view.

[0036] The upper electrode 13 is, for example, IrO 2 The upper electrode 13 has a two-layer structure in which an iridium oxide film and an Ir (iridium) film are laminated in this order from the piezoelectric film 12 side. The upper electrode 13 may be composed of a single film of platinum (Pt), for example. The thickness of the upper electrode 13 is, for example, about 80 nm.

[0037] The piezoelectric film 12 is, for example, a PZT (PbZr x Ti 1-x O 3 A lead zirconate titanate film can be applied. Such a piezoelectric film 12 is made of a sintered body of metal oxide crystal. The piezoelectric film 12 is formed in the same shape as the upper electrode 13 in a plan view. The thickness of the piezoelectric film 12 is, for example, about 2 μm.

[0038] The above-mentioned first hydrogen barrier film 21 prevents deterioration of the characteristics of the piezoelectric film 12 due to hydrogen reduction. Also, the first hydrogen barrier film 21 prevents metal elements (Pb, Zr, Ti when the piezoelectric film 12 is PZT) from escaping from the piezoelectric film 12, maintaining good piezoelectric characteristics of the piezoelectric film 12, and preventing metal from diffusing into the movable film 5A when the piezoelectric film 12 is formed.

[0039] The lower electrode 11 is, for example, TiO 2It has a two-layer structure in which a (titanium oxide) film and a Pt (platinum) film are laminated in this order from the first hydrogen barrier film 21 side. Alternatively, the lower electrode 11 can be formed of a single film such as an Au (gold) film, a Cr (chromium) layer, or a Ni (nickel) layer. The lower electrode 11 has a main electrode portion 11A in contact with the lower surface of the piezoelectric film 12, and an extension portion 11B extending to an area outside the piezoelectric film 12. The thickness of the lower electrode 11 is, for example, about 200 nm.

[0040] A second hydrogen barrier film 22 is formed on the first hydrogen barrier film 21 so as to cover the exposed surface of the piezoelectric element 10. The second hydrogen barrier film 22 is made of, for example, Al 2 O 3 (Alumina) The second hydrogen barrier film 22 has a thickness of, for example, about 50 nm to 100 nm In this embodiment, the second hydrogen barrier film 22 has a thickness of, for example, about 80 nm.

[0041] The second hydrogen barrier film 22 is provided to prevent deterioration of the characteristics of the piezoelectric film 12 due to hydrogen reduction. The first hydrogen barrier film 21 and the second hydrogen barrier film 22 constitute the hydrogen barrier film 22 that covers the entire piezoelectric element 10. However, as described later, the hydrogen barrier film 23 has an opening 35 and contact holes 41, 42, and 43 for exposing a part of the piezoelectric element 10 formed therein.

[0042] An interlayer insulating film 24 is formed on the movable film formation layer 5 so as to cover the exposed surface of the movable film formation layer 5 and the exposed surface of the hydrogen barrier film 23. The interlayer insulating film 24 is made up of a first interlayer insulating film 25 and a second interlayer insulating film 26.

[0043] The first interlayer insulating film 25 is formed on the upper surface of the hydrogen barrier film 23 (more specifically, on the upper surface of the second hydrogen barrier film 22). In other words, the first interlayer insulating film 25 is formed in the same pattern as the second hydrogen barrier film 22.

[0044] The second interlayer insulating film 26 is formed on the movable film formation layer 5 so as to cover the exposed surface of the movable film formation layer 5 and the exposed surface of the first interlayer insulating film 25. Therefore, in the region where the hydrogen barrier 23 does not exist, the first interlayer insulating film 25 is not formed, and only the second interlayer insulating film 26 in the interlayer insulating film 24 is formed.

[0045] The first interlayer insulating film 25 and the second interlayer insulating film 26 are, for example, SiO 2 films formed using TEOS (tetraethoxysilane) as a raw material. 2 The first interlayer insulating film 25 and the second interlayer insulating film 26 are made of, for example, SiO 2 The first interlayer insulating film 25 may be a silicon nitride film, a low hydrogen SiN film, or the like. The thickness of the first interlayer insulating film 25 is, for example, about 20 nm to 100 nm. In this embodiment, the thickness of the first interlayer insulating film 25 is, for example, about 50 nm. The thickness of the second interlayer insulating film 26 is, for example, about 100 nm to 200 nm. In this embodiment, the thickness of the second interlayer insulating film 26 is, for example, about 150 nm.

[0046] An upper wiring 27, a lower wiring 28, and a dummy wiring 29 (see FIGS. 2 and 8) are formed on the second interlayer insulating film 26. These wirings 27, 28, and 29 are made of, for example, a laminated film in which a TiN film and an Al film are laminated in this order from the interlayer insulating film 26 side. The thickness of these wirings 27, 28, and 29 is, for example, about 500 nm.

[0047] The upper wiring 27 includes a first upper contact portion 27A, a second upper contact portion 27B, an upper connection line portion 27C (see FIGS. 2 and 4), and an upper pad portion 27D (see also FIGS. 2 and 4). The first upper contact portion 27A is connected to one end portion (the upstream end portion in the ink flow direction 50) of the upper electrode 13. The second upper contact portion 27B is connected to the other end portion (the downstream end portion in the ink flow direction 50) of the upper electrode 13. The upper connection line portion 27C connects the first upper contact portion 27A and the second upper contact portion 27B to the upper pad portion 27D.

[0048] Between the first upper contact portion 27A and the upper electrode 13, a first upper contact hole 41 is formed, which continuously penetrates the interlayer insulating film 24 and the second hydrogen barrier film 22. One end of the first upper contact portion 27A enters the first upper contact hole 41 and is connected to the upper electrode 13 within the first upper contact hole 41. As shown in FIG. 4, the first upper contact portion 27A extends from above the upper electrode 13 along the longitudinal direction of the upper electrode 13 to the outside of one end of the upper electrode 13, and then extends in one direction along the lateral direction of the upper electrode 13 and is connected to the upper connection line portion 27C outside the pressure chamber 8.

[0049] Similarly, a second upper contact hole 42 is formed between the second upper contact portion 27B and the upper electrode 13, continuously penetrating the interlayer insulating film 24 and the second hydrogen barrier film 22. One end of the second upper contact portion 27B enters the second upper contact hole 42 and is connected to the upper electrode 13 in the second upper contact hole 42. The second upper contact portion 27B extends from above the upper electrode 13 to the outside of the other end of the upper electrode 13 along the longitudinal direction of the upper electrode 13, and then extends in one direction along the lateral direction of the upper electrode 13, and is connected to the upper connection line portion 27C outside the pressure chamber 8. The upper pad portion 27D is formed in an outer region of the pressure chamber 8. The upper connection line portion 27C is connected to the upper pad portion 27D.

[0050] Lower wiring 28 includes lower contact portion 28A, lower connection line portion 28B (see FIG. 2), and lower pad portion 28C (see FIGS. 2 and 8). Lower contact portion 28A is connected to one end (the upstream end in ink flow direction 60) of lower electrode 11. Lower connection line portion 28B connects lower contact portion 28A to lower pad portion 28C.

[0051] Between the lower contact portion 28A and the lower electrode 11 (specifically, the extension portion 11B), a pair of lower contact holes 43 are formed continuously penetrating the interlayer insulating film 24 and the second hydrogen barrier film 22. The pair of lower contact holes 43 are arranged at an interval in the short side direction of the lower electrode 11.

[0052] The lower contact portion 28A enters each of the pair of lower contact holes 43 and is connected to the lower electrode 11 within each lower contact hole 33. The lower contact portion 28A extends from above the lower electrode 11, across the outer edge of the pressure chamber 8, to the outside of the pressure chamber 8, and is connected to the lower connection line portion 28B. The lower pad portion 28C (see FIGS. 2 and 8) is formed in the outer region of the pressure chamber 8. The lower connection line portion 28B is connected to the lower pad portion 28C.

[0053] The dummy wiring 29 is a wiring that is not electrically connected to either the upper wiring 27 or the lower wiring 28. The dummy wiring 29 is formed in the same process as the process for forming the upper wiring 27 and the lower wiring 28.

[0054] A passivation film 30 is formed on the second interlayer insulating film 26 to cover the upper wiring 27, the lower wiring 28, the dummy wiring 29 and the second interlayer insulating film 26. The passivation film 30 is made of, for example, SiO 2 The passivation film 30 may be a SiN film. The thickness of the passivation film 30 may be, for example, about 500 nm.

[0055] An opening 35 that exposes the center of the upper electrode 13 is formed in the second hydrogen barrier film 22, the interlayer insulating film 24, and the passivation film 30. This opening 35 is formed in order to increase the displacement of the movable film 5A.

[0056] A pair of upper pad openings 44 exposing a portion of the upper pad portion 27D are formed in the passivation film 30. The pair of upper pad openings 44 are formed above the upper pad portion 27D and spaced apart in a direction along the ink flow direction 50. Upper electrode pads 51 covering the pair of upper pad openings 44 are formed on the passivation film 30. The upper electrode pads 51 enter the pair of upper pad openings 44, respectively, and are connected to the upper pad portion 27D within each upper pad opening 44.

[0057] 8, a pair of lower pad openings 45 that expose a portion of the lower pad portion 28C are formed in the passivation film 30. The pair of lower pad openings 45 are formed above the lower pad portion 28C and spaced apart in the direction along the ink flow direction 60. Lower electrode pads 52 that cover the pair of lower pad openings 45 are formed on the passivation film 30. The lower electrode pads 52 enter the pair of lower pad openings 45, respectively, and are connected to the lower pad portion 28C within each lower pad opening 45.

[0058] The upper electrode pad 51 and the lower electrode pad 52 are made of a laminated film in which, for example, a TiW film and an Au film are laminated in this order from the side (the pad portions 27D and 28C) of the passivation film 30. The thickness of the upper electrode pad 51 and the lower electrode pad 52 is, for example, about 0.6 μm.

[0059] A first liquid contact film (ink resistant film) 31 having ink resistance is formed on the surface of the passivation film 30 and the entire inner surface (side and bottom surfaces) of the opening 35, except for a predetermined region including the upper electrode pad 51 and a predetermined region including the lower electrode pad 52. Since the bottom surface of the opening 35 is the upper surface of the upper electrode 13, a part of the first liquid contact film 31 is formed in contact with the upper surface of the upper electrode 13 facing the opening 35. The first liquid contact film 31 is formed to protect the piezoelectric element 10 from ink. The first liquid contact film 31 is, for example, a SiTaO film. The first liquid contact film 31 may be a TaO film.

[0060] The thickness of the first liquid contact film 31 is preferably 5 nm to 100 nm, and more preferably 10 nm to 50 nm. If the thickness is less than 5 nm, the film may not function as a protective film, and if the thickness is more than 100 nm, the film may hinder the displacement of the movable film 5A. In this embodiment, the thickness of the first liquid contact film 31 is, for example, about 20 nm.

[0061] A first ink inflow passage 53 penetrating the first liquid contact film 31, the passivation film 30, the second interlayer insulating film 26 and the movable film formation layer 5 is formed at a position corresponding to the end of the ink flow path 6 on the ink inflow section 7 side. A first ink outflow passage 54 penetrating the first liquid contact film 31, the passivation film 30, the second interlayer insulating film 26 and the movable film formation layer 5 is formed at a position corresponding to the end of the ink flow path 6 on the ink outflow section 9 side.

[0062] An adhesion-reinforcing film 61 is formed on the first liquid-contact film 31. The adhesion-reinforcing film 61 is formed in order to enhance adhesion between the substrate assembly SA and the adhesive layer 62 when the protection substrate 4 is bonded to the substrate assembly SA by the adhesive layer 62.

[0063] The protective substrate 4 is made of, for example, a silicon substrate. In this embodiment, the thickness of the protective substrate 4 is about 400 μm. An oxide film 4a is formed on the entire surface of the protective substrate 4 except for the outer peripheral side surface. The protective substrate 4 is disposed on the substrate assembly SA so as to cover the piezoelectric element 10. The protective substrate 4 is bonded to the substrate assembly SA via an adhesion-strengthening film 61 and an adhesive layer 62.

[0064] The protective substrate 4 has an accommodating recess 72 on an opposing surface 71 facing the substrate assembly SA. The piezoelectric element 10 is accommodated in the accommodating recess 72. A second ink inflow passage 73 communicating with the first ink inflow passage 53 and a second ink outflow passage 74 communicating with the first ink outflow passage 54 are formed in the protective substrate 4, the adhesion strengthening film 61 and the adhesive layer 62. Furthermore, the protective substrate 4 is formed with a first opening 75 and a second opening 76 (see FIG. 1) for exposing the upper electrode pad 51 and the lower electrode pad 52, respectively.

[0065] The second ink inflow passage 73, the second ink outflow passage 74, the first opening 75, and the second opening 76 penetrate the protection substrate 4. An ink tank (not shown) that stores ink is disposed on the protection substrate 4.

[0066] A second liquid contact film 65 is formed on the inner surfaces of the second ink inflow passage 73, the first ink inflow passage 53, the ink flow path 6, the first ink outflow passage 54, the second ink outflow passage 74 and the nozzle holes 3a, 43, and on the surface (lower surface) of the nozzle substrate 3 opposite to the ink flow path 6 side. The second liquid contact film 65 is, for example, a SiTaO film. The second liquid contact film 65 may also be a TaO film. The film thickness of the second liquid contact film 65 is, for example, about 50 nm.

[0067] A water-repellent film 66 is formed on the entire surface of the second liquid-contacting film 65. The water-repellent film 66 is made of a film made of, for example, a compound containing a fluoroalkyl group. The thickness of the water-repellent film 66 is, for example, about 10 nm.

[0068] The piezoelectric element 10 is formed at a position facing the pressure chamber 8 across the movable film 5A and the first hydrogen barrier film 21. In other words, the piezoelectric element 10 is formed so as to contact the surface of the first hydrogen barrier film 21 opposite the pressure chamber 8. Ink is circulated from the ink tank through the second ink inflow passage 73, the first ink inflow passage 53, the ink flow path 6, the first ink outflow passage 54 and the second ink outflow passage 74. As a result, the pressure chamber 8 is always filled with ink.

[0069] The movable film 5A defines the top surface of the pressure chamber 8 and faces the pressure chamber 8. The movable film 5A is supported by a portion of the actuator substrate 2 surrounding the pressure chamber 8, and has flexibility that allows it to deform in a direction facing the pressure chamber 8 (in other words, in the thickness direction of the movable film 5A).

[0070] The lower wiring 28 and the upper wiring 27 are connected to a drive circuit (not shown). Specifically, the upper electrode pad 51 and the drive circuit are connected via a connection metal member (not shown). The lower electrode pad 52 (see FIGS. 2 and 8) and the drive circuit are connected via a connection metal member (not shown). When a drive voltage is applied from the drive circuit to the piezoelectric element 10, the piezoelectric film 12 deforms due to the inverse piezoelectric effect. As a result, the movable film 5A deforms together with the piezoelectric element 10, thereby causing a change in the volume of the pressure chamber 8 and pressurizing the ink in the pressure chamber 8. The pressurized ink passes through the nozzle hole 3a and is ejected as fine droplets from the ink ejection port 3b.

[0071] Note that the ink inflow portion 7 (ink inflow passages 53, 73) in FIG. 5 may be the ink outflow portion 9 (ink outflow passages 54, 74), and the ink outflow portion 9 (ink outflow passages 54, 74) in FIG. 5 may be the ink inflow portion 7 (ink inflow passages 53, 73). In other words, the ink circulation direction may be reversed.

[0072] With reference to FIGS. 1 to 9, the configuration of the inkjet print head 1 will be described in more detail. In the following description, the left side of FIG. 1 is referred to as "left", the right side of FIG. 1 is referred to as "right", the lower side of FIG. 1 is referred to as "front", and the upper side of FIG. 1 is referred to as "rear", respectively.

[0073] As shown in FIG. 1, the planar shape of the inkjet print head 1 is rectangular. In this embodiment, the planar shapes and sizes of the actuator substrate 2, the protective substrate 4, and the nozzle substrate 3 are substantially the same as the planar shape and size of the inkjet print head 1.

[0074] On the actuator substrate 2, in a plan view, a plurality of rows of piezoelectric elements 10 (hereinafter referred to as "piezoelectric element rows") arranged in a stripe pattern at intervals in the front-rear direction are provided in a plurality of rows at intervals in the left-right direction. In this embodiment, for the sake of convenience of explanation, it is assumed that two rows of piezoelectric element rows are provided.

[0075] 4, an ink flow path 6 (pressure chamber 8) is formed in the actuator substrate 2 for each piezoelectric element 10. Therefore, in a plan view, the actuator substrate 2 is provided with two ink flow path rows (pressure chamber rows) spaced apart in the left-right direction, each row being made up of a plurality of ink flow paths 6 (pressure chambers 8) arranged in stripes at intervals in the front-rear direction.

[0076] A first ink inflow passage 53 and a first ink outflow passage 54 are provided for each of the multiple ink flow paths 6 in each ink flow path row. The first ink inflow passage 53 is disposed on the ink inflow section 7. The first ink outflow passage 54 is disposed on the ink outflow section 9. In this embodiment, for one ink flow path 6, the first ink inflow passage 53 is disposed on the left end of the ink flow path 6, and the first ink outflow passage 54 is disposed on the right side of the ink flow path 6.

[0077] The first ink inflow passage 53 (ink inflow section 7) and the first ink outflow passage 54 (ink outflow section 9) may be arranged laterally opposite between the left ink flow path row and the right ink flow path row. In other words, the ink flow direction 50 may be opposite between the left ink flow path row and the right ink flow path row.

[0078] In each ink flow path row, the multiple ink flow paths 6 are formed at equal intervals in their width direction with small intervals (for example, about 30 μm to 350 μm) between them. Each ink flow path 6 extends in an elongated manner along the ink flow direction 50. The ink flow path 6 comprises an ink inflow section 7 communicating with a first ink inflow passage 53, an ink outflow section 9 communicating with a first ink outflow passage 54, and a pressure chamber 8 communicating with the ink inflow section 7 and the ink outflow section 9.

[0079] The pressure chamber 8 is a region between the first ink inflow passage 53 (ink inflow section 7) and the first ink outflow passage 54 (ink outflow section 9) of the ink flow passage 6 shown by the dashed line in Fig. 4. The pressure chamber 8 has an elongated rectangular shape extending along the ink flow direction 50 in a plan view. In other words, the top surface of the pressure chamber 8 has two side edges along the ink flow direction 50 and two end edges along a direction perpendicular to the ink flow direction 50. The pressure chamber 8 (ink flow passage 6) has a width slightly larger than the ink inflow section 7 and the ink outflow section 9 in a plan view.

[0080] In a plan view, the piezoelectric element 10 has a rectangular shape that is long in the longitudinal direction of the pressure chamber 8 (movable membrane 5A). The longitudinal length of the piezoelectric element 10 is shorter than the longitudinal length of the pressure chamber 8 (movable membrane 5A). Both end edges along the lateral direction of the piezoelectric element 10 are disposed inside the corresponding end edges of the movable membrane 5A with a predetermined interval therebetween. In addition, the lateral width of the piezoelectric element 10 is narrower than the lateral width of the movable membrane 5A. Both end edges along the lateral direction of the piezoelectric element 10 are disposed inside the corresponding end edges of the movable membrane 5A with a predetermined interval therebetween.

[0081] The lower electrode 11 has a rectangular shape long in the longitudinal direction of the pressure chamber 8 (movable membrane 5A) in plan view. The lower electrode 11 includes a main electrode portion 11A having a rectangular shape in plan view constituting the piezoelectric element 10, and an extension portion 11B having a rectangular ring shape in plan view drawn from the periphery of the main electrode portion 11A in a direction along the surface of the movable membrane forming layer 5. The longitudinal length of the main electrode portion 11A is shorter than the longitudinal length of the movable membrane 5A. Both end edges of the main electrode portion 11A are disposed inside the corresponding end edges of the movable membrane 5A with a predetermined interval therebetween. In addition, the lateral width of the main electrode portion 11A is narrower than the lateral width of the movable membrane 5A. Both side edges of the main electrode portion 11A are disposed inside the corresponding side edges of the movable membrane 5A with a predetermined interval therebetween.

[0082] Both end edges of extension 11B (both end edges of lower electrode 11) are disposed on the inside with a predetermined gap from the corresponding end edges of movable film 5A. Both side edges of extension 11B (both side edges of lower electrode 11) are disposed on the outside with a predetermined gap from the corresponding side edges of movable film 5A.

[0083] The upper electrode 13 is formed in a rectangular shape in the same pattern as the main electrode portion 11A of the lower electrode 11 in a plan view. That is, the longitudinal length of the upper electrode 13 is shorter than the longitudinal length of the movable film 5A. Both end edges of the upper electrode 13 are disposed inside the corresponding end edges of the movable film 5A with a predetermined interval therebetween. In addition, the lateral width of the upper electrode 13 is narrower than the lateral width of the movable film 5A. Both side edges of the upper electrode 13 are disposed inside the corresponding side edges of the movable film 5A with a predetermined interval therebetween.

[0084] The piezoelectric film 12 is formed in a rectangular shape in the same pattern as the upper electrode 13 in a plan view. That is, the length of the piezoelectric film 12 in the longitudinal direction is shorter than the length of the movable film 5A in the longitudinal direction. Both end edges of the piezoelectric film 12 are arranged on the inside with a predetermined interval from the corresponding end edges of the movable film 5A. In addition, the width of the piezoelectric film 12 in the lateral direction is narrower than the width of the movable film 5A in the lateral direction. Both side edges of the piezoelectric film 12 are arranged on the inside with a predetermined interval from the corresponding side edges of the movable film 5A. The lower surface of the piezoelectric film 12 is in contact with the upper surface of the main electrode portion 11A of the lower electrode 11, and the upper surface of the piezoelectric film 12 is in contact with the lower surface of the upper electrode 13.

[0085] 1 and 2, one upper electrode pad 51 and one lower electrode pad 52 are provided for each of two piezoelectric elements adjacent to each other on the left and right (hereinafter referred to as a "pair of left and right piezoelectric elements 10").

[0086] The upper electrode pad 51 is disposed to the right of the first ink outflow passage 54 on the right side of the pair of left and right piezoelectric elements 10. The upper electrode pad 51 is disposed within the first opening 75 of the protection substrate 4. Below the upper electrode pad 51, an upper pad portion 27D (upper wiring 27) electrically connected to the upper electrode pad 51 is disposed.

[0087] The lower electrode pad 52 is disposed to the left of the first ink inflow passage 53 on the left side of the pair of left and right piezoelectric elements 10. The lower electrode pad 52 is disposed within the second opening 76 of the protection substrate 4. Below the lower electrode pad 52, a lower pad portion 28C (lower wiring 28) electrically connected to the lower electrode pad 52 is disposed.

[0088] A plurality of upper electrode pads 51 corresponding to the plurality of pairs of left and right piezoelectric elements 10 are arranged in a line in the front-rear direction on the right side of the right-side piezoelectric element row in a plan view, as shown in Figures 1 and 2. A plurality of lower electrode pads 52 corresponding to the plurality of pairs of left and right piezoelectric elements 10 are arranged in a line in the front-rear direction on the left side of the left-side piezoelectric element row in a plan view, as shown in Figures 1 and 2.

[0089] In the right-side piezoelectric element 10 of the pair of left and right piezoelectric elements 10, the first upper contact portion 27A and the second upper contact portion 27B of the upper wiring 27 are connected to the upper pad portion 27D via an upper connection line portion 27C arranged on the front side of the pair of left and right piezoelectric elements 10. This upper connection line portion 27C extends rightward from the left end of the right-side piezoelectric element 10 on the front side of the pair of left and right piezoelectric elements 10 and is connected to the upper pad portion 27D.

[0090] In the right-side piezoelectric element 10 of the pair of left and right piezoelectric elements 10, the lower contact portion 28A of the lower wiring 28 is electrically connected to the left end portion of the lower electrode 11 of the right-side piezoelectric element 10. This lower contact portion 28A is connected to the lower pad portion 28C via a lower connection line portion 28B arranged on the front side of the pair of left and right piezoelectric elements 10. This lower connection line portion 28B extends leftward from the left end of the lower electrode 11 of the right-side piezoelectric element 10 on the front side of the pair of left and right piezoelectric elements 10, and is connected to the lower pad portion 28C.

[0091] In the left piezoelectric element 10 of the pair of left and right piezoelectric elements 10, the first upper contact portion 27A and the second upper contact portion 27B of the upper wiring 27 are connected to the upper pad portion 27D via an upper connection line portion 27C arranged on the rear side of the pair of left and right piezoelectric elements 10. This upper connection line portion 27C extends rightward from the left end of the left piezoelectric element 10 on the rear side of the pair of left and right piezoelectric elements 10 and is connected to the upper pad portion 27D.

[0092] In the left piezoelectric element 10 of the pair of left and right piezoelectric elements 10, the lower contact portion 28A of the lower wiring 28 is electrically connected to the left end portion of the lower electrode 11 of the left piezoelectric element 10. This lower contact portion 28A is connected to the lower pad portion 28C via a lower connection line portion 28B arranged on the rear side of the pair of left and right piezoelectric elements 10. This lower connection line portion 28B extends leftward from the left end of the lower electrode 11 of the left piezoelectric element 10 on the rear side of the pair of left and right piezoelectric elements 10, and is connected to the lower pad portion 28C.

[0093] An upper pad opening 44 (see FIG. 5) that exposes a part of the upper pad portion 27D of the upper wiring 27 is formed in the passivation film 30. An upper electrode pad 51 is provided on the passivation film 30 so as to cover the upper pad opening 44. The upper electrode pad 51 is connected to the upper wiring 27 within the upper pad opening 44.

[0094] A lower pad opening 45 (see FIG. 8) that exposes a part of the lower pad portion 28C of the lower wiring 28 is formed in the passivation film 30. A lower electrode pad 52 is provided on the passivation film 30 so as to cover the lower pad opening 45. The lower electrode pad 52 is connected to the lower wiring 28 within the lower pad opening 45.

[0095] 1, 3, 5 and 8, the protective substrate 4 is formed with a plurality of second ink inflow passages 73 communicating with the plurality of first ink inflow passages 53, and a plurality of second ink outflow passages 74 communicating with the plurality of first ink outflow passages 54. In each of the left-side piezoelectric element row and the right-side piezoelectric element row, the plurality of second ink inflow passages 73 are arranged in a row with intervals between them in the front-rear direction, and the plurality of second ink outflow passages 74 are arranged in a row with intervals between them in the front-rear direction.

[0096] The second ink inflow passage 73 has a rectangular shape in a plan view and is in the same pattern as the first ink inflow passage 53 on the actuator substrate 2 side. In each of the left-side piezoelectric element row and the right-side piezoelectric element row, the second ink inflow passage 73 is aligned with the first ink inflow passage 53 in a plan view. The second ink outflow passage 74 has a rectangular shape in a plan view and is in the same pattern as the first ink outflow passage 54 on the actuator substrate 2 side. In each of the left-side piezoelectric element row and the right-side piezoelectric element row, the second ink outflow passage 74 is aligned with the first ink outflow passage 54 in a plan view.

[0097] Further, a first opening 75 for exposing all of the upper electrode pads 51 and a second opening 76 for exposing all of the lower electrode pads 52 are formed in the protective substrate 4. These openings 75, 76 have a rectangular shape that is long in the front-rear direction in a plan view.

[0098] The dummy wirings 29 are arranged on both the left and right sides of the second ink inflow passage 73 (first ink inflow passage 53) and on both the left and right sides of the second ink outflow passage 74 (first ink outflow passage 54) in a plan view. The dummy wirings 29 support the protection substrate 4 and form a base that enhances adhesion to the opposing surface of the protection substrate 4.

[0099] Fig. 10 is a schematic plan view showing an example of a pattern of the interlayer insulating film 24 of the inkjet printhead 1. Fig. 11 is a schematic plan view showing an example of a pattern of the passivation film 30 of the inkjet printhead.

[0100] In this embodiment, the interlayer insulating film 24 and the passivation film 30 are formed on the actuator substrate 2 over almost the entire outer region of the accommodating recess 72 of the protection substrate 4 in a plan view. However, in this region, the interlayer insulating film 24 is formed with a first ink inflow passage 53, a first ink outflow passage 54, and a lower contact hole 43. The lower contact hole 43 is also formed in the second hydrogen barrier film 22. In this region, the passivation film 30 is formed with the first ink inflow passage 53, the first ink outflow passage 54, an upper pad opening 44, and a lower pad opening 45.

[0101] In the inner region of the accommodation recess 72 of the protective substrate 4, the interlayer insulating film 24 and the passivation film 30 are formed only on the periphery including both ends (upper wiring region) where the upper wiring 27 (upper contact portions 27A, 27B) are present. In this region, the second hydrogen barrier film 22 is also formed only on the periphery.

[0102] In this region, the passivation film 30 is formed so as to cover the upper surface and side surfaces of the upper wiring 27 on the interlayer insulating film 24. In other words, an opening 35 is formed in the second hydrogen barrier film 22, the interlayer insulating film 24 and the passivation film 30 in a region excluding a peripheral portion including the upper wiring region within the inner region of the accommodation recess 72 in a plan view. A first upper contact hole 41 and a second upper contact hole 42 are further formed in the second hydrogen barrier film 22 and the interlayer insulating film 24.

[0103] The second hydrogen barrier film 22 may be present in the opening 35. In other words, the second hydrogen barrier film 22 may be formed on the entire upper surface of the upper electrode 13. In this case, since the bottom surface of the opening 35 is the upper surface of the upper electrode 13, a part of the first liquid contact film 31 is formed in contact with the upper surface of the second hydrogen barrier film 22 facing the opening 35.

[0104] A method for manufacturing the inkjet printhead 1 will be outlined below.

[0105] FIG. 13 is a plan view of a semiconductor wafer as the original substrate of the actuator substrate, with a partial area shown enlarged.

[0106] A semiconductor wafer (actuator wafer) 100 serving as an original substrate of the actuator substrate 2 is made of, for example, a silicon wafer. A surface 100a of the actuator wafer 100 corresponds to a surface 2a of the actuator substrate. A plurality of functional element forming regions 101 are arranged in a matrix on the surface 100a of the actuator wafer 100. A scribe region (boundary region) 102 is provided between adjacent functional element forming regions 101. The scribe region 102 is a strip-shaped region having a substantially constant width, and is formed in a lattice shape extending in two perpendicular directions. Planned cutting lines 103 are set on the scribe region 102.

[0107] By carrying out necessary processes on the actuator wafer 100, a substrate assembly aggregate (SA aggregate) 110 (see FIG. 12T) is created in which the components of the substrate assemblies SA are formed on the functional element forming regions 101. However, the substrate assembly aggregate (SA aggregate) 110 does not have the ink flow paths 6, the second liquid contact film 65, and the water repellent film 66 formed thereon.

[0108] A protective substrate assembly 130 (see FIG. 12X) integrally including a plurality of protective substrates 4 corresponding to each functional element formation region 101 of the substrate assembly assembly 110 is prepared in advance. However, the second liquid contact film 65 and the water repellent film 66 are not formed on the protective substrate assembly 130. The protective substrate assembly 130 is produced by carrying out necessary processes on a semiconductor wafer (protective substrate wafer) as the original substrate of the protective substrate 4. The protective substrate wafer is made of, for example, a silicon wafer.

[0109] Also, a nozzle substrate assembly 150 (see FIG. 12Z3) integrally including a plurality of nozzle substrates 3 corresponding to each functional element forming region 101 of the substrate assembly assembly 110 is prepared in advance. However, the second liquid contact film 65 and the water repellent film 66 are not formed on the nozzle substrate assembly 150. The nozzle substrate assembly 150 is produced by carrying out necessary processes on a semiconductor wafer (nozzle wafer) as the original substrate of the nozzle substrate 3. The nozzle wafer is made of, for example, a silicon wafer.

[0110] Once the substrate assembly aggregate 110 is created, the protective substrate aggregate 130 is bonded to the substrate assembly aggregate 110. Next, an ink flow path 6 is formed in the substrate assembly aggregate 110. Next, the nozzle substrate aggregate 150 is bonded to the substrate assembly aggregate 110. As a result, an intermediate combined body (see FIG. 12Z3) is obtained in which the substrate assembly aggregate 110 having the ink flow path 6, the protective substrate aggregate 130, and the nozzle substrate aggregate 150 are bonded together.

[0111] Next, the second liquid-contacting film 65 and the water-repellent film 66 are formed on the intermediate assembly, thereby obtaining the inkjet print head assembly 170 (see FIG. 12Z5).

[0112] Thereafter, the inkjet printhead aggregate 170 is cut (diced) by a dicing blade along the planned cutting lines 103. This cuts out individual inkjet printheads (chips) 1, each including a functional element forming region 101. The inkjet printhead 1 has a scribe region 102 on its periphery, and the functional element forming region 101 in a central region surrounded by the scribe region 102.

[0113] A method for manufacturing the inkjet printhead 1 will now be described in detail.

[0114] 12A to 12Z5 are cross-sectional views showing the manufacturing process of the inkjet printhead 1, and correspond to the cross section of FIG.

[0115] First, as shown in FIG. 12A, an actuator wafer 100 is prepared. However, the actuator wafer 100 used is thicker than the final actuator substrate 2. Then, a movable film formation layer 5 is formed on the surface 100a of the actuator wafer 100. Specifically, a silicon oxide film (for example, 1.5 μm thick) is formed on the surface 100a of the actuator wafer 100. When the movable film formation layer 5 is composed of a laminated film of a silicon oxide film and a silicon nitride film, a silicon oxide film (for example, 0.7 μm thick) is formed on the surface 100a of the actuator wafer 100, and a silicon nitride film (for example, 0.7 μm thick) is formed on the silicon oxide film.

[0116] Next, as shown in FIG. 12B, a first hydrogen barrier film (first hydrogen barrier material film) 21 is formed on the movable film formation layer 5. The first hydrogen barrier film 21 is, for example, Al 2 O 3The first hydrogen barrier film 21 is made of a film (for example, 50 nm to 100 nm thick). The first hydrogen barrier film 21 prevents deterioration of the characteristics of the piezoelectric film 12 due to hydrogen reduction. The first hydrogen barrier film 21 also prevents metal atoms from escaping from the piezoelectric film 12 to be formed later. If metal electrons escape, the piezoelectric characteristics of the piezoelectric film 12 may deteriorate. If the escaped metal atoms are mixed into the silicon layer constituting the movable film formation layer 5 (movable film 5A), the durability of the movable film 5A may deteriorate.

[0117] 12C, a lower electrode film 81, which is a material layer of the lower electrode 11, is formed on the first hydrogen barrier film 21. The lower electrode film 81 is, for example, TiO 2 A Pt / TiO film (e.g., 10 nm to 40 nm thick) is used as the lower layer and a Pt film (e.g., 10 nm to 400 nm thick) is used as the upper layer. 2 The lower electrode film 81 may be formed by a sputtering method.

[0118] Next, a piezoelectric material film 82, which is the material of the piezoelectric film 12, is formed on the entire surface of the lower electrode film 81. Specifically, for example, the piezoelectric material film 82 is formed to a thickness of, for example, 1 μm to 3 μm by a sol-gel method. Such a piezoelectric material film 82 is made of a sintered body of metal oxide crystal grains.

[0119] Next, an upper electrode film 83, which is the material of the upper electrode 13, is formed on the entire surface of the piezoelectric material film 82. The upper electrode film 83 may be, for example, a single film of platinum (Pt). The upper electrode film 83 may be, for example, IrO 2 A thin Ir film (e.g., 40 nm to 160 nm thick) is used as the lower layer, and an Ir film (e.g., 40 nm to 160 nm thick) is used as the upper layer. 2 / Ir laminated film. Such an upper electrode film 83 may be formed by sputtering.

[0120] 12D to 14F, the upper electrode film 83, the piezoelectric material film 82, the lower electrode film 81, and the first hydrogen barrier film 21 are patterned. First, a resist mask (not shown) of the pattern of the upper electrode 13 is formed by photolithography. Then, as shown in FIGS. 12D and 12E, the upper electrode film 83 and the piezoelectric material film 82 are successively etched using this resist mask as a mask, thereby forming the upper electrode 13 and the piezoelectric film 12 of the upper electrode pattern.

[0121] Next, after the resist mask is peeled off, a resist mask (not shown) of the pattern of the lower electrode 11 is formed by photolithography. Then, as shown in Fig. 12F, the lower electrode film 81 and the first hydrogen barrier film 21 are successively etched using this resist mask as a mask, thereby forming the lower electrode 11 and the first hydrogen barrier film 21 of the lower electrode pattern. As a result, the lower electrode 11 consisting of the main electrode portion 11A and the extension portion 11B is formed. In this manner, the piezoelectric element 10 consisting of the main electrode portion 11A of the lower electrode 11, the piezoelectric film 12, and the upper electrode 13 is formed.

[0122] Next, as shown in FIG. 12G, after the resist mask is peeled off, a second hydrogen barrier film (second hydrogen barrier material film) 22 is formed to cover the entire surface. The second hydrogen barrier film 22 is made of Al 2 O 3 It may be a film, and the film thickness may be, for example, 50 nm to 100 nm.

[0123] 12H, a first interlayer insulating film (first interlayer insulating material film) 25 is formed on the entire surface of the second hydrogen barrier film 22. The first interlayer insulating film 25 is a SiO 2 It may be a film, and the film thickness is, for example, about 20 nm to 100 nm.

[0124] Next, a resist mask (not shown) of the pattern of the first interlayer insulating film 25 is formed by photolithography. Then, as shown in Fig. 12I, the first interlayer insulating film 25 and the second hydrogen barrier film 22 are successively etched using this resist mask, so that the first interlayer insulating film 25 and the second hydrogen barrier film 22 are patterned into a predetermined second hydrogen barrier film pattern. As a result, the piezoelectric element 10 is covered with the hydrogen barrier film 23 consisting of the first hydrogen barrier film 21 and the second hydrogen barrier film 22.

[0125] 12J, after the resist mask is peeled off, a second interlayer insulating film 26 is formed to cover the entire surface. The second interlayer insulating film 26 is a SiO 2 It may be a film, and the film thickness is, for example, about 100 nm to 200 nm.

[0126] Next, as shown in FIG. 12K, photolithography and etching are used to form a first upper contact hole 41, a second upper contact hole 42 and a lower contact hole 43 that continuously penetrate the second interlayer insulating film 26, the first interlayer insulating film 25 and the second hydrogen barrier film 22.

[0127] Next, as shown in FIG. 12L, a wiring film 84 constituting upper wiring 27, lower wiring 28 and dummy wiring 29 is formed on second interlayer insulating film 26 including inside contact holes 41, 42, and 43 by sputtering.

[0128] Next, as shown in FIG. 12M, the wiring film 84 is patterned by photolithography and etching, thereby simultaneously forming the upper wiring 27, the lower wiring 28, and the dummy wiring 29.

[0129] 12N, a passivation film 30 is formed on the surface of the second interlayer insulating film 26 to cover the wirings 27, 28, and 29. The passivation film 30 is made of, for example, SiO 2 The passivation film 30 is formed by, for example, plasma CVD.

[0130] Next, a resist mask (not shown) having openings corresponding to the upper pad opening 44 and the lower pad opening 45 is formed by photolithography, and the passivation film 30 is etched using this resist mask. As a result, pad openings 44, 45 are formed in the passivation film 30 as shown in FIG. 12O. After the resist mask is peeled off, a metal film 85 constituting the upper electrode pad 51 and the lower electrode pad 52 is formed on the passivation film 30 by a sputtering method. The metal film 85 is made of, for example, a laminated film made of a lower TiW film and an upper Au film.

[0131] Next, as shown in FIG. 12P, the pad metal film 85 is patterned by photolithography and etching to form an upper electrode pad 51 connected to the upper wiring 27 and a lower electrode pad 52 connected to the lower wiring 28 on the passivation film 30.

[0132] Next, after the resist mask is peeled off, a resist mask (not shown) having an opening corresponding to the opening 35 is formed by photolithography, and the passivation film 30, the interlayer insulating film 24, and the second hydrogen barrier film 22 are successively etched using this resist mask. As a result, as shown in FIG. 12Q, an opening 35 exposing the central portion of the upper surface of the upper electrode 13 is formed in the passivation film 30, the interlayer insulating film 24, and the second hydrogen barrier film 22.

[0133] Next, as shown in FIG. 12R, after the resist mask is peeled off, a first liquid contact film 31 is formed to cover the entire surface. The first liquid contact film 31 is formed by, for example, ALD (Atomic Layer Deposition) or MOCVD. The film formation temperature is, for example, about 80° C. to 350° C. The first liquid contact film 31 is, for example, a SiTaO film. The film thickness of the first liquid contact film 31 is, for example, about 5 nm to 100 nm.

[0134] Next, as shown in Fig. 12S, a resist mask 86 having openings corresponding to the first ink inflow passage 53 and the first ink outflow passage 54 is formed by photolithography. Using this resist mask 86 as a mask, the first liquid contact film 31, the passivation film 30, the second interlayer insulating film 26 and the movable film formation layer 5 are successively etched. As a result, as shown in Fig. 12T, the first ink inflow passage 53 and the first ink outflow passage 54 penetrating the first liquid contact film 31, the passivation film 30, the second interlayer insulating film 26 and the movable film formation layer 5 are formed. In this way, a substrate assembly aggregate 110 is produced.

[0135] Next, as shown in FIG. 12U, after the resist mask is peeled off, an adhesion enhancing agent is applied to the entire surface by spin coating. Then, a baking process is performed to bake the adhesion enhancing agent. As a result, an adhesion enhancing film 61 that covers the entire surface is formed. The adhesion enhancing agent is, for example, AP9000C (product name) manufactured by Dow Electronic Materials, and its film thickness is, for example, about 10 nm. The baking condition is preferably 140° C. or higher in an air atmosphere.

[0136] Next, as shown in FIG. 12V, an adhesive is applied to the entire surface of the adhesion-strengthening film 61 by spin coating. After that, a baking process is performed to bake the adhesive. As a result, an adhesive material layer 87 is formed on the entire surface of the adhesion-strengthening film 61. In this embodiment, a photosensitive adhesive is used as the adhesive. The photosensitive adhesive is, for example, CYCLOTENETM6505 (product name) manufactured by Dow Electronic Materials, and its film thickness is, for example, 1 μm to 7 μm. The baking conditions are preferably 90° C. or more and less than 150° C. in an air atmosphere. The reason why a temperature less than 150° C. is preferable is that the adhesive may be oxidized when baking at 150° C. or more in an air atmosphere.

[0137] 12W, the adhesive material layer 87 is exposed and developed to pattern the adhesive material layer 87. As a result, portions of the adhesive material layer 87 that correspond to the opening 35, the first ink inflow passage 53 and the first ink outflow passage 54 of the actuator substrate 2, and the first opening 75 and the second opening 76 of the protection substrate 4 are removed. As a result, the adhesive layer 62 is selectively formed on the adhesion strengthening film 61.

[0138] 12X, the protective substrate aggregate 130 is bonded to the substrate assembly aggregate 110 via the adhesive layer 62. At this time, the two are bonded such that the second ink inflow passage 73 and the second ink outflow passage 74 of the protective substrate aggregate 130 coincide with the corresponding first ink inflow passage 53 and the first ink outflow passage 54 of the substrate assembly aggregate 110.

[0139] 12Y, back grinding is performed to thin the actuator wafer 100. The actuator wafer 100 is polished from the back surface 100b, thereby thinning the actuator wafer 100. For example, the actuator wafer 100, which is initially about 625 μm thick, is thinned to about 70 μm thick.

[0140] Next, as shown in FIG. 12Z1, an adhesive layer 63 is formed on the entire back surface 100b of the actuator wafer 100. The adhesive layer 63 may be composed of, for example, an adhesion-strengthening film applied to the back surface 100b of the actuator wafer 100 and an adhesive layer applied on the adhesion-strengthening film. The adhesion-strengthening film is, for example, AP3000C (product name) manufactured by Dow Electronic Materials, and its film thickness is, for example, about 100 Å. In this case, a baking process is performed after the adhesion-strengthening film is applied. In addition, the adhesive is, for example, CYCLOTENETM3022 (product name) manufactured by Dow Electronic Materials, and its film thickness is, for example, about 1.2 μm. In this case, a baking process is performed after the adhesive is applied.

[0141] Next, a resist mask (not shown) having openings corresponding to the ink flow paths 6 is formed on the front surface (lower surface) of the adhesive layer 63 by photolithography. Then, using this resist mask as a mask, the actuator wafer 100 is etched from the rear surface 100b. As a result, as shown in FIG. 12Z2, the ink flow paths 6 (ink inflow portion 7, pressure chamber 8, and ink outflow portion 9) are formed in the actuator wafer 100. Furthermore, this etching also removes the adhesion-reinforcing film 61 on the side and bottom surface of the first ink inflow passage 53 and the adhesion-reinforcing film 61 on the side and bottom surface of the first ink outflow passage 54.

[0142] Next, as shown in Fig. 12Z3, the nozzle substrate aggregate 150 is bonded to the rear surface 100b of the actuator wafer 100. This bonds the substrate assembly aggregate 110 on which the laminated films 65, 66 of the second liquid contact film 65 and the water repellent film 66 are not formed, the protective substrate aggregate 130 on which the laminated films 65, 66 are not formed, and the nozzle substrate aggregate 150 on which the laminated films 65, 66 are not formed. This provides an intermediate bonded body.

[0143] Next, as shown in Fig. 12Z4, a second liquid contact film 65 is formed on the entire exposed surface of the intermediate assembly, including the inner surfaces of the second ink inflow passage 73, the first ink inflow passage 53, the ink flow path 6, the first ink outflow passage 54, the second ink outflow passage 74, and the nozzle hole 3a. The second liquid contact film 65 is, for example, a SiTaO film. The second liquid contact film 65 may also be a TaO film. The film thickness of the second liquid contact film 65 is about 50 nm.

[0144] Thereafter, a water-repellent film 66 is formed on the entire surface of the second liquid-contacting film 65. The water-repellent film 66 is made of a film made of, for example, a compound containing a fluoroalkyl group. The thickness of the water-repellent film 66 is about 10 nm.

[0145] 12Z5, the laminated films 65, 66 of the second liquid contact film 65 and the water repellent film 66 on the upper surface of the protective substrate assembly 130 and the laminated films 65, 66 facing the first opening 75 and the second opening 76 of the protective substrate assembly 130 are removed by photolithography and etching. Furthermore, the laminated films of the first liquid contact film 31 and the passivation film 30 in the first opening 75 and the second opening 76 of the protective substrate assembly 130 are removed by this etching. As a result, the upper surface of the upper electrode pad 51 is exposed to the first opening 75, and the upper surface of the lower electrode pad 52 is exposed to the second opening 76.

[0146] This provides an inkjet printhead aggregate 170 consisting of the substrate assembly aggregate 110, the protective substrate aggregate 130, and the nozzle substrate aggregate 150. After this, the inkjet printhead aggregate 170 is cut by a dicing blade along the planned cutting lines 103. In other words, a process for cutting out the inkjet printheads 1 individually is performed.

[0147] Upon completion of this process, the actuator wafer 100 in the substrate assembly aggregate 110 becomes the actuator substrate 2 of each inkjet printhead 1. Additionally, the protective substrate aggregate 130 becomes the protective substrate 4 of each inkjet printhead 1. Additionally, the nozzle substrate aggregate 150 becomes the nozzle substrate 3 of each inkjet printhead 1. In this manner, individual inkjet printheads 1 having the structure shown in FIGS. 1 to 9 are obtained.

[0148] In the method for manufacturing an inkjet printhead according to this embodiment, a nozzle substrate assembly 150 is bonded to a substrate assembly assembly 110 to which a protective substrate assembly 130 is fixed, thereby producing an inkjet printhead assembly 170. The inkjet printhead assembly 170 is then diced to cut out individual inkjet printheads 1. This allows the inkjet printhead 1 to be manufactured more efficiently than, for example, a case in which an inkjet printhead is manufactured by manufacturing individual substrate assemblies SA and then bonding nozzle substrates 3 to the individual substrate assemblies SA.

[0149] 14A to 14D are cross-sectional views showing a part of the manufacturing process of the comparative example.

[0150] The comparative example has a different configuration of the interlayer insulating film from the embodiment of Fig. 5. The interlayer insulating film of the comparative example is composed of a single interlayer insulating film 224 whose pattern in plan view is the same as the pattern of the first interlayer insulating film 25 of the embodiment. The thickness of the interlayer insulating film 224 of the comparative example is approximately equal to the sum of the thickness of the first interlayer insulating film 25 and the thickness of the second interlayer insulating film 26 of the embodiment.

[0151] Fig. 14A corresponds to Fig. 12H of the embodiment. That is, in Fig. 14A, an interlayer insulating film 224 is formed on the entire surface of a second hydrogen barrier film (second hydrogen barrier material film). The interlayer insulating film 224 is a SiO 2 It may be a film, the thickness of which is, for example, about 50 nm.

[0152] Next, a resist mask (not shown) of the pattern of the interlayer insulating film 224 is formed by photolithography. Then, as shown in Fig. 14B, the interlayer insulating film 224 and the second hydrogen barrier film 22 are successively etched using this resist mask as a mask, so that the interlayer insulating film 224 and the second hydrogen barrier film 22 are patterned into a predetermined second hydrogen barrier film pattern. As a result, the piezoelectric element 10 is covered with the hydrogen barrier film 23 consisting of the first hydrogen barrier film 21 and the second hydrogen barrier film 22.

[0153] Next, as shown in FIG. 14C, photolithography and etching are used to form a first upper contact hole 41, a second upper contact hole 42 and a lower contact hole 43 that continuously penetrate the second interlayer insulating film 26, the first interlayer insulating film 25 and the second hydrogen barrier film 22.

[0154] 14D, a wiring film 84 is formed by sputtering on the second interlayer insulating film 26 including the insides of the contact holes 41, 42, and 43. Thereafter, the wiring film 84 is patterned to form upper wirings 27, lower wirings 28, and dummy wirings 29 having the same patterns as those of the embodiment.

[0155] FIG. 15 is an enlarged cross-sectional view showing a portion D in FIG. 14D.

[0156] In the comparative example, the outer peripheral end surface 22a of the second hydrogen barrier film 22 is in contact with the wiring film 84. That is, in the comparative example, an upper contact portion for connecting the upper wiring 27 to the upper electrode 13 and a lower contact portion for connecting the lower wiring 28 to the lower electrode 11 are in contact with the second hydrogen barrier film 22, and the upper wiring 27 and the lower wiring 28 are in contact with the outer peripheral end surface 22a of the second hydrogen barrier film 22.

[0157] 6, 7, and 9, in this embodiment, the second interlayer insulating film 26 is present between the outer peripheral end surface 22a of the second hydrogen barrier film 22 and the wirings 27, 28, so that the outer peripheral end surface 22a of the second hydrogen barrier film 22 does not contact the wirings 27, 28. That is, in this embodiment, the second interlayer insulating film 26 keeps the wirings 27, 28 out of contact with the second hydrogen barrier film 22, except for the upper contact portions 27A, 27B and the lower contact portion 28A.

[0158] In other words, in this embodiment, it is possible to reduce the area where the wirings 27, 28 are in contact with the second hydrogen barrier film 22, as compared to the comparative example. As a result, even if the hydrogen barrier film 23 is corroded by ink that has infiltrated onto the surface of the substrate assembly SA from the joint between the protection substrate 4 and the substrate assembly SA, the wirings 27, 28 are less likely to deteriorate.

[0159] It is not necessary to form the first hydrogen barrier film 21. In this case, the outer peripheral end face of the second hydrogen barrier film 22 does not contact the wirings 27 and 28, and therefore the same effect can be obtained.

[0160] Furthermore, in this embodiment, an opening 35 for exposing the central portion of the upper electrode 13 is formed in the laminated film of the second hydrogen barrier film 22, the interlayer insulating film 24 and the passivation film 30, so that the displacement of the movable film 5A can be made larger than when the opening 35 is not formed.

[0161] In this embodiment, a first liquid contact film 31 is formed so as to cover the upper surface of the upper electrode 13. This makes it possible to suppress deterioration of the piezoelectric element 10 due to ink that has infiltrated onto the surface of the substrate assembly SA from the joint between the protection substrate 4 and the substrate assembly SA, etc.

[0162] In particular, in this embodiment, the opening 35 for exposing the center of the upper electrode 13 is formed in the laminated film of the second hydrogen barrier film 22, the interlayer insulating film 24, and the passivation film 30, so that ink is more likely to penetrate into the piezoelectric element 10 through the opening 35 than when the opening 35 is not formed. In this embodiment, the first liquid contact film 31 is formed on the entire inner surface (side surface and bottom surface) of the opening 35. This first liquid contact film 31 has the effect of preventing ink that has penetrated into the opening 35 from penetrating into the piezoelectric element 10. Therefore, even if ink penetrates into the opening 35 (more specifically, onto the surface of the first liquid contact film 31 formed on the inner surface of the opening 35), deterioration of the piezoelectric element 10 due to the ink can be effectively suppressed.

[0163] Incidentally, even when the second hydrogen barrier film 22 is formed in the center of the upper electrode 13 and the opening 35 is formed only in the interlayer insulating film 24 and the passivation film 30, the first liquid contact film 31 is formed over the entire inner surface (side surface and bottom surface) of the opening 35. Therefore, even if ink enters the opening 35, deterioration of the piezoelectric element 10 due to the ink can be effectively suppressed.

[0164] Furthermore, if no opening 35 is formed in the laminated film of the second hydrogen barrier film 22, the interlayer insulating film 24, and the passivation film 30, the first liquid contact film 31 will be formed on the surface of the passivation film 30 on the upper surface of the upper electrode 13. Even in this case, the first liquid contact film 31 can prevent the piezoelectric element 10 from being deteriorated by ink.

[0165] In this embodiment, the protective substrate 4 is bonded to the actuator substrate 2 (substrate assembly SA) by an adhesion-strengthening film 61 formed on the actuator substrate 2 (substrate assembly SA) side and a photosensitive adhesive layer 62 formed on the adhesion-strengthening film 61. Since a photosensitive adhesive is used as the adhesive, it is easy to pattern the adhesive layer 62. This makes it possible to simplify the process of bonding the protective substrate 4 to the actuator substrate 2.

[0166] In addition, since an adhesion-strengthening film 61 is formed on the actuator substrate 2 side, the adhesion between the protective substrate 4 and the actuator substrate 2 can be increased, and ink can be prevented from penetrating into the surface side of the substrate assembly SA from the joint between the protective substrate 4 and the actuator substrate 2.

[0167] In addition, since the adhesion enhancing agent is applied to the actuator substrate 2 side (surface of the substrate assembly SA) by spin coating, the surface of the adhesion enhancing film 61 can be formed into a flat surface with few irregularities. In addition, since the photosensitive adhesive is applied onto the adhesion enhancing layer 61 by spin coating, the surface of the adhesive layer 62 can be formed into a flat surface with few irregularities. This makes it less likely that air bubbles will be generated at the joint between the protective substrate 4 and the actuator substrate 2 compared to when the adhesive is applied by stamping. This makes it possible to effectively prevent ink from penetrating into the surface side of the substrate assembly SA from the joint between the protective substrate 4 and the actuator substrate 2.

[0168] Although the first embodiment of the present disclosure has been described above, the first disclosure can also be implemented in other embodiments.

[0169] Although two rows of piezoelectric elements (rows of pressure chambers) are provided on the actuator substrate 2, only one row of piezoelectric elements (rows of pressure chambers) may be provided, or three or more rows of piezoelectric elements (rows of pressure chambers) may be provided.

[0170] Furthermore, in the above embodiment, the first hydrogen barrier film 21 is formed between the movable film formation layer 5 and the lower electrode 11, but the first hydrogen barrier film 21 may be omitted.

[0171] In the above embodiment, PZT is used as an example of the material of the piezoelectric film. However, other materials such as lead titanate (PbPO 3 ), potassium niobate (KNbO 3 ), lithium niobate (LiNbO 3 ), lithium tantalate (LiTaO 3 Alternatively, a piezoelectric material made of a metal oxide such as SiO 2 may be used. [2] Regarding the Second Disclosure The second disclosure described below can be extracted from the description of the specification relating to the embodiment of the first disclosure described above and the descriptions of FIGS. 1 to 15. [2-1] Second Purpose of This Disclosure A second object of the present disclosure is to provide an inkjet printhead capable of suppressing deterioration of a piezoelectric element due to ink, and a method for manufacturing the same. [2-2] Second Configuration of the Disclosure A1. An actuator substrate having an ink flow path including a pressure chamber; a movable film forming layer including a movable film disposed above the pressure chamber and defining a top surface of the pressure chamber; a piezoelectric element including a lower electrode disposed on the movable film, a piezoelectric film formed on the lower electrode, and an upper electrode formed on the piezoelectric film; a hydrogen barrier film covering at least the entire side surface of the upper electrode and the piezoelectric film on the surface of the piezoelectric element; an interlayer insulating film formed on the movable film formation layer so as to cover the hydrogen barrier film; a wiring formed on the interlayer insulating film and connected to the piezoelectric element; a passivation film formed on the interlayer insulating film and covering the wiring; and a liquid-contacting membrane formed over an upper surface of the upper electrode.

[0172] In this configuration, since a liquid contact film is provided so as to cover the upper surface of the upper electrode, deterioration of the piezoelectric element due to ink can be suppressed.

[0173] A laminated film is formed on the upper surface of the upper electrode, the laminated film being made of the hydrogen barrier film, the interlayer insulating film, and the passivation film, and having an opening that exposes a part of the upper surface of the upper electrode; The inkjet printhead described in "A1.", wherein the liquid contact film is formed so as to be in contact with the upper surface of the laminate film and the entire inner surface of the opening.

[0174] A3. The hydrogen barrier film is formed on the upper surface of the upper electrode; a laminated film including the interlayer insulating film and the passivation film and having an opening exposing a part of the hydrogen barrier film is formed on the hydrogen barrier film on the upper surface of the upper electrode; The inkjet printhead described in "A1.", wherein the liquid contact film is formed so as to be in contact with the upper surface of the laminate film and the entire inner surface of the opening.

[0175] A4. An inkjet printhead according to "A2." or "A3.", wherein the liquid contact film is formed over the entire upper surface of the passivation film in an area other than above the upper surface of the upper electrode.

[0176] A5. The lower electrode includes a main electrode portion that contacts the lower surface of the piezoelectric film and an extension portion that extends from the main electrode portion to the outside of the piezoelectric film, An inkjet printhead described in any of "A1." to "A4.", wherein the hydrogen barrier film covers the entire side surfaces of the upper electrode, the piezoelectric film, and the lower electrode, a portion of the top surface of the upper electrode, and the entire top surface of the extension.

[0177] A6. An inkjet printhead according to "A5.", wherein the hydrogen barrier film is also formed over the entire lower surface of the lower electrode.

[0178] A7. An inkjet printhead according to any one of "A1." to "A6.", wherein the wiring includes an upper wiring connected to the upper electrode and a lower wiring connected to the lower electrode.

[0179] A8. An upper contact hole exposing a part of the upper surface of the upper electrode is formed in the hydrogen barrier film and the interlayer insulating film formed on the upper surface of the upper electrode, and one end of the upper wiring is connected to the upper electrode through the upper contact hole; An inkjet printhead described in "A7.", wherein a lower contact hole exposing a portion of the upper surface of the lower electrode is formed in the hydrogen barrier film and the interlayer insulating film formed on the upper surface of the lower electrode, and one end of the lower wiring is connected to the lower electrode via the lower contact hole.

[0180] A9. The inkjet printhead according to any one of "A1." to "A8.", wherein the liquid-contacting film is a SiTaO film or a TaO film.

[0181] A10. The inkjet print head according to "A9.", wherein the thickness of the liquid contact film is 5 nm or more and 100 nm or less.

[0182] A11. The inkjet print head according to "A9.", wherein the thickness of the liquid-contacting film is 10 nm or more and 50 nm or less.

[0183] A step of forming a piezoelectric element on a substrate, the piezoelectric element comprising a lower electrode, a piezoelectric film formed on the lower electrode, and an upper electrode formed on the piezoelectric film; forming a hydrogen barrier film on the substrate to cover the piezoelectric element; forming an interlayer insulating film on the substrate to cover the hydrogen barrier film; a wiring forming step of forming an upper wiring, one end of which is connected to the upper electrode, and a lower wiring, one end of which is connected to the lower electrode, on the interlayer insulating film; forming a passivation film on a surface of the interlayer insulating film to cover the upper wiring and the lower wiring; forming an opening in the hydrogen barrier film, the interlayer insulating film, and the passivation film on the upper electrode to expose a portion of an upper surface of the upper electrode; forming a liquid contact film on the entire inner surface of the opening and on an upper surface of the passivation film.

[0184] A step of forming a piezoelectric element on a substrate, the piezoelectric element comprising a lower electrode, a piezoelectric film formed on the lower electrode, and an upper electrode formed on the piezoelectric film; forming a hydrogen barrier film on the substrate to cover the piezoelectric element; forming an interlayer insulating film on the substrate to cover the hydrogen barrier film; a wiring forming step of forming an upper wiring, one end of which is connected to the upper electrode, and a lower wiring, one end of which is connected to the lower electrode, on the interlayer insulating film; forming a passivation film on a surface of the interlayer insulating film to cover the upper wiring and the lower wiring; forming an opening in the interlayer insulating film and the passivation film among the hydrogen barrier film, the interlayer insulating film, and the passivation film on the upper electrode, to expose a part of an upper surface of the upper electrode; forming a liquid contact film on the entire inner surface of the opening and on an upper surface of the passivation film.

[0185] A14. The wiring forming process is forming contact holes which continuously penetrate the interlayer insulating film and the hydrogen barrier film, the contact holes exposing a part of an upper surface of the upper electrode and a lower contact hole exposing a part of an upper surface of the lower electrode; forming a wiring film on the interlayer insulating film including inside the upper contact hole and the lower contact hole; The method for manufacturing an inkjet printhead according to "A12." or "A13." further comprises a step of forming the upper wiring and the lower wiring by patterning the wiring film. [3] Third Disclosure The third disclosure described below can be extracted from the description of the specification relating to the embodiment of the first disclosure described above and the descriptions of FIGS. 1 to 15. [3-1] 3. Purpose of this Disclosure An object of the third disclosure is to provide an inkjet print head and a method for manufacturing the same, which can simplify the bonding process of a protective substrate to an actuator substrate. [3-2] Configuration of the Third Disclosure B1. An actuator substrate having an ink flow path including a pressure chamber, A movable film forming layer including a movable film disposed on the pressure chamber and partitioning a top surface portion of the pressure chamber, A piezoelectric element disposed on the movable film, And a protective substrate bonded to the actuator substrate so as to cover the piezoelectric element, The protective substrate is bonded to the actuator substrate via an adhesive layer, The adhesive layer includes an adhesion strengthening layer formed on the actuator substrate side and a photosensitive adhesive layer formed on the adhesion strengthening layer, an inkjet print head.

[0186] In this configuration, it becomes possible to simplify the bonding process of the protective substrate to the actuator substrate.

[0187] B2. The inkjet print head according to "B1.", wherein the protective substrate has a housing recess that opens toward the actuator substrate and houses the piezoelectric element, and an ink passage communicating with the ink flow path.

[0188] B3. A hydrogen barrier film covering at least a part of the surface of the piezoelectric element, An interlayer insulating film formed on the movable film forming layer so as to cover the hydrogen barrier film, A wiring formed on the interlayer insulating film and connected to the piezoelectric element, And a coating insulating film formed on the interlayer insulating film and covering the wiring, The inkjet print head according to "B1." or "B2.", wherein the adhesion strengthening layer is formed on the coating insulating film.

[0189] B4. The coating insulating film is formed on the interlayer insulating film and includes a passivation film that coats the wiring, and a liquid contact film formed on the passivation film, the inkjet print head according to "B3.".

[0190] B5. The piezoelectric element includes a lower electrode disposed on the movable film, a piezoelectric film formed on the lower electrode, and an upper electrode formed on the piezoelectric film, the wiring includes an upper wiring connected to the upper electrode and a lower wiring connected to the lower electrode, the inkjet print head according to any one of "B1." to "B4.".

[0191] B6. An upper contact hole that exposes a part of the upper surface of the upper electrode is formed in the hydrogen barrier film formed on the upper surface of the upper electrode and the interlayer insulating film, and one end of the upper wiring is connected to the upper electrode through the upper contact hole, a lower contact hole that exposes a part of the upper surface of the lower electrode is formed in the hydrogen barrier film formed on the upper surface of the lower electrode and the interlayer insulating film, and one end of the lower wiring is connected to the lower electrode through the lower contact hole, the inkjet print head according to "B5.".

[0192] B7. The inkjet print head according to any one of "B1." to "B6.", including a nozzle substrate that is joined to the surface of the actuator substrate opposite to the surface on the movable film side, partitions the bottom surface of the pressure chamber, and has a nozzle hole communicating with the pressure chamber.

[0193] B8. A step of forming a piezoelectric element including a lower electrode, a piezoelectric film formed on the lower electrode, and an upper electrode formed on the piezoelectric film on the actuator substrate; a step of forming a hydrogen barrier film covering the piezoelectric element on the actuator substrate; a step of forming an interlayer insulating film covering the hydrogen barrier film on the actuator substrate; a wiring forming step of forming an upper wiring, one end of which is connected to the upper electrode, and a lower wiring, one end of which is connected to the lower electrode, on the interlayer insulating film; an insulating film forming step of forming a covering insulating film on a surface of the interlayer insulating film to cover the upper wiring and the lower wiring; a first coating step of coating an adhesion enhancing agent on the insulating coating film by a spin coating method; a second coating step of coating a photosensitive adhesive on the liquid contact film by a spin coating method; A step of patterning the photosensitive adhesive by exposing and developing the photosensitive adhesive; and bonding a protection substrate covering the piezoelectric elements to the actuator substrate via the photosensitive adhesive.

[0194] B9. A first baking step of baking the adhesion promoter after the first application step; The method for manufacturing an inkjet printhead described in "B8." further includes a second forming step of baking the photosensitive adhesive after the second applying step.

[0195] B10. The insulating film forming process forming a passivation film on a surface of the interlayer insulating film to cover the upper wiring and the lower wiring; forming a liquid-contacting film on an upper surface of the passivation film; The method for manufacturing an inkjet printhead described in "B8." or "B9.", wherein the covering insulating film includes a laminated film of the passivation film and the liquid contact film.

[0196] B11. The insulating film forming process forming a passivation film on a surface of the interlayer insulating film to cover the upper wiring and the lower wiring; forming an opening in the hydrogen barrier film, the interlayer insulating film, and the passivation film on the upper electrode to expose a portion of an upper surface of the upper electrode; forming a liquid-contacting film on the entire inner surface of the opening and on an upper surface of the passivation film; The method for manufacturing an inkjet printhead described in "B8." or "B9.", wherein the covering insulating film includes a laminated film of the passivation film and the liquid contact film.

[0197] B12. The wiring forming process includes: forming contact holes which continuously penetrate the interlayer insulating film and the hydrogen barrier film, the contact holes exposing a part of an upper surface of the upper electrode and a lower contact hole exposing a part of an upper surface of the lower electrode; forming a wiring film on the interlayer insulating film including inside the upper contact hole and the lower contact hole; The method for manufacturing an inkjet printhead according to any one of "B8." to "B11.", further comprising a step of forming the upper wiring and the lower wiring by patterning the wiring film.

[0198] B13. An inkjet printhead described in any of "B8." to "B12.", comprising a step of bonding a nozzle substrate that defines a bottom portion of the pressure chamber and has a nozzle hole communicating with the pressure chamber to a surface of the actuator substrate opposite to the surface on the movable membrane side.

[0199] In the above embodiment, the first liquid contact film 31 is formed on the passivation film 30, but the first liquid contact film 31 may be omitted. In that case, the passivation film 30 is an example of the "coating insulating film" of the third disclosure. [4] Regarding the fourth disclosure Hereinafter, the fourth disclosure will be described with reference to Fig. 16 to Fig. 31. The reference numerals in Fig. 16 to Fig. 31 are unrelated to the reference numerals in Fig. 1 to Fig. 15. [4-1] 4. Purpose of this Disclosure JP 2018-69685 A discloses an inkjet printhead. The inkjet printhead of JP 2018-69685 A includes an actuator substrate having a pressure chamber as an ink flow path, a movable film formed on the actuator substrate, and a piezoelectric element provided on the movable film. The inkjet printhead of JP 2018-69685 A further includes a nozzle substrate bonded to the lower surface of the actuator substrate and having a nozzle hole communicating with the pressure chamber, and a protective substrate bonded to the upper surface of the actuator substrate and covering the piezoelectric element. The piezoelectric element is composed of a lower electrode formed on the movable film, an upper electrode disposed on the lower electrode, and a piezoelectric film sandwiched therebetween.

[0200] The nozzle substrate described in JP 2018-69685 A includes a silicon substrate having a first surface and a second surface, a silicon oxide film formed on the second surface of the silicon substrate, and a water-repellent film formed on the surface of the silicon oxide film. The nozzle substrate has a nozzle hole penetrating the nozzle substrate in the thickness direction.

[0201] In an inkjet recording device equipped with this type of inkjet printhead, ink may adhere to the second surface of the nozzle substrate, so a wiping mechanism is provided that wipes the second surface with a wiping member such as a wiper.

[0202] However, when the second surface of the nozzle substrate is wiped by the wiping mechanism, the water-repellent film formed on the second surface may be damaged, leading to a risk of deterioration. When the water-repellent film deteriorates, the contact angle and contact circumference of the meniscus with the inner surface of the nozzle hole change, resulting in a problem of a change in the ink ejection performance.

[0203] A fourth object of the present disclosure is to provide a nozzle substrate and a manufacturing method thereof that can suppress changes in ink ejection performance.

[0204] A fourth object of the present disclosure is to provide an inkjet print head including a nozzle substrate capable of suppressing changes in ink ejection performance. [4-2] Fourth Configuration of the Disclosure C1. A main substrate having a first surface and a second surface and a nozzle hole penetrating in a thickness direction; an adhesion layer formed on a portion of the exposed surface of the main substrate; a water-repellent film formed on a surface of the adhesion layer opposite to the main substrate, the nozzle hole comprises a recess formed on the first surface of the main substrate, and an ink ejection passage formed on a bottom surface of the recess, penetrating a bottom wall of the recess, and having an ink ejection port on the second surface side of the main substrate; the adhesion layer has a main adhesion layer formed on the second surface, and an adhesion layer intrusion portion that enters the ink ejection passage from a peripheral portion of the ink ejection port in the main adhesion layer and is formed on an inner surface of an end portion of the ink ejection passage on the ink ejection port side, The water-repellent film has a main water-repellent film formed on the surface of the main adhesion layer, and a water-repellent film entry portion extending from the peripheral portion of the ink ejection port in the main water-repellent film along the surface of the adhesion layer entry portion, a portion of which enters into the ink ejection port.

[0205] In this configuration, the water-repellent film has a main water-repellent film formed on the surface of the main adhesion layer, and a water-repellent film entry portion that extends from the peripheral portion of the ink ejection orifice in the main water-repellent film along the surface of the adhesion layer entry portion, with a portion of it entering the ink ejection orifice, thereby suppressing changes in the ink ejection performance.

[0206] C2. The nozzle substrate according to "C1.", wherein the intrusion length of the portion of the water-repellent film intrusion portion that intrudes into the ink ejection passage is 0.1 μm or more and 3 μm or less.

[0207] C3. A nozzle substrate according to "C1." or "C2.", wherein the recess is cylindrical, and the ink ejection passage is cylindrical, concentric with the recess, and has a smaller cross section than the recess.

[0208] C4. A nozzle substrate described in "C1." or "C2.", wherein the recess is a truncated cone shape whose cross section gradually becomes smaller from the first surface side to the second surface side of the main substrate, and the ink ejection passage is cylindrical and concentric with the recess.

[0209] C5. A nozzle substrate according to any one of "C1." to "C4.", wherein the main substrate is a silicon substrate, the adhesion layer is a SiOC layer, and the water-repellent film is an FDTS film.

[0210] C6. The nozzle substrate according to "C5.", wherein the film thickness of the silicon substrate is 40 μm or more and 200 μm or less.

[0211] C7. The nozzle substrate according to "C6.", wherein the adhesion layer has a thickness of 100 Å or more and 200 Å or less.

[0212] C8. The nozzle substrate according to "C7.", wherein the water-repellent film has a thickness of 30 Å or more and 80 Å or less.

[0213] C9. The nozzle substrate according to "C7." or "C8.", wherein the thickness of the laminated film of the adhesion layer and the water-repellent film is 100 Å or more and 300 Å or less.

[0214] C10. An actuator substrate having an ink flow path including a pressure chamber; a movable film forming layer including a movable film disposed above the pressure chamber and defining a top surface of the pressure chamber; A piezoelectric element formed on the movable film; a nozzle substrate which is bonded to a surface of the actuator substrate opposite to the surface on the movable membrane side, which defines a bottom portion of the pressure chamber and has a nozzle hole communicating with the pressure chamber; The nozzle substrate is a nozzle substrate as described in any one of "C1." to "C9.", and the first surface of the main substrate is bonded to a surface of the actuator substrate opposite to the surface on the movable membrane side.

[0215] C11. Further includes a protection substrate bonded to the actuator substrate so as to cover the piezoelectric element; The inkjet printhead described in "C10.", wherein the protective substrate has an accommodating recess that opens toward the actuator substrate and accommodates the piezoelectric element, and an ink supply path that is formed outside one end of the accommodating recess in a planar view and communicates with one end of the ink flow path.

[0216] C12. A first step of forming a main substrate having a first surface and a second surface, the main substrate having a nozzle hole including a recess opening on the first surface and an ink ejection passage penetrating a bottom wall of the recess and having an ink ejection port on the second surface side; a second step of forming an adhesion layer and a water-repellent film in that order on the entire exposed surface of the main substrate, including the first surface, the second surface, and the inner surface of the nozzle hole; a third step of attaching a masking tape consisting of a base film and an adhesive formed on one side of the base film to an outer surface of the laminate film formed on the second surface of the main substrate so as to cover the laminate film consisting of the adhesion layer and the water-repellent film formed on the second surface of the main substrate and the ink ejection orifices in the ink ejection passages and so that the adhesive penetrates into an end of the ink ejection passage on the ink ejection orifice side; a fourth step of etching the laminated film using the masking tape as a mask to remove a portion of the laminated film other than a first portion formed on the second surface of the main substrate and a second portion formed on an inner surface of the ink discharge passage at an end portion on the ink discharge port side; and a fifth step of removing the masking tape.

[0217] C13. The method for manufacturing a nozzle substrate according to "C12.", wherein the intrusion length of the portion of the second portion that intrudes into the ink ejection passage is 0.1 μm or more and 3 μm or less.

[0218] C14. A method for manufacturing a nozzle substrate according to "C12." or "C13.", wherein the recess is cylindrical, and the ink ejection passage is cylindrical, concentric with the recess, and has a smaller cross section than the recess.

[0219] C15. A method for manufacturing a nozzle substrate described in "C12." or "C13.", wherein the recess is a truncated cone shape whose cross section gradually becomes smaller from the first surface side to the second surface side of the main substrate, and the ink ejection passage is cylindrical and concentric with the recess.

[0220] C16. The method for producing a nozzle substrate according to any one of "C12." to "C15.", wherein the main substrate is a silicon substrate, the adhesion layer is a SiOC layer, and the water-repellent film is an FDTS film. [4-3] Fourth embodiment of the present disclosure The fourth embodiment of the present disclosure will be described in detail below with reference to FIGS.

[0221] FIG. 16 is a schematic plan view for explaining the configuration of an inkjet printhead according to an embodiment of the present invention. FIG. 17 is a schematic partially enlarged plan view showing an enlargement of a portion A in FIG. 16, including a protective substrate. FIG. 18 is a schematic partially enlarged plan view showing an enlargement of a portion A in FIG. 16, omitting the protective substrate. FIG. 19 is a schematic cross-sectional view taken along line XIX-XIX in FIG. 17. FIG. 20 is an enlarged cross-sectional view showing an enlargement of a nozzle hole in FIG. 19. FIG. 21 is a plan view seen from the arrow XXI-XXI in FIG. 20. FIG. 22 is a schematic cross-sectional view taken along line XXII-XXII in FIG. 20. FIG. 23 is a schematic cross-sectional view taken along line XXIII-XXIII in FIG. 17. FIG. 24 is a schematic cross-sectional view taken along line XXIV-XXIV in FIG. 17.

[0222] The structure of the inkjet printhead 1 will now be briefly described with reference to FIG.

[0223] The inkjet printhead 1 comprises an actuator substrate assembly SA including an actuator substrate 2 and a piezoelectric element 9, a nozzle substrate 3, and a protection substrate 4. Hereinafter, the actuator substrate assembly SA will be referred to as the substrate assembly SA.

[0224] A movable film formation layer 10 is laminated on the surface 2a of the actuator substrate 2. An ink flow path (ink reservoir) 5 is formed in the actuator substrate 2. In this embodiment, the ink flow path 5 is formed penetrating the actuator substrate 2. The ink flow path 5 is formed to extend elongatedly along the ink flow direction 41 shown by the arrow in FIG. 19. The ink flow path 5 is composed of an ink inflow section 6 at the upstream end (the left end in FIG. 19) of the ink flow direction 41, and a pressure chamber 7 communicating with the ink inflow section 6. In FIG. 19, the boundary between the ink inflow section 6 and the pressure chamber 7 is indicated by a two-dot chain line.

[0225] As shown in Figs. 19 to 22, the nozzle substrate 3 includes a silicon substrate 30 having a first surface 30a on the pressure chamber 7 side, a second surface 30b on the opposite side to the pressure chamber 7 side, and a nozzle hole 20 penetrating in the thickness direction. The silicon substrate 30 is an example of a "main substrate" in the present invention. The nozzle substrate 3 further includes an adhesion layer 31 formed on a part of the exposed surface excluding the first surface 30a of the silicon substrate 30, and a water-repellent film 32 formed on the surface of the adhesion layer 31 on the opposite side to the silicon substrate 30. In Fig. 20, M indicates a meniscus which is the surface of the ink inside the nozzle hole 20.

[0226] The nozzle substrate 3 is attached to the back surface 2b of the actuator substrate 2 with the first surface 30a of the silicon substrate 30 facing the back surface 2b of the actuator substrate 2. The nozzle substrate 3 defines the ink flow path 5 together with the actuator substrate 2 and the movable film formation layer 10. More specifically, the nozzle substrate 3 defines the bottom portion of the ink flow path 5.

[0227] The nozzle hole 20 comprises a recess 20a facing the pressure chamber 7 and an ink ejection passage 20b formed in the bottom surface of the recess 20a. The recess 20a is formed in the first surface 30a of the silicon substrate 30. The ink ejection passage 20b is formed in the bottom surface of the recess 20a and penetrates the bottom wall of the recess 20a. The ink ejection passage 20b has an ink ejection port 20c on the second surface 30b side of the silicon substrate 30.

[0228] The recess 20a is cylindrical with a circular cross section. The ink ejection passage 20b is cylindrical with a circular cross section concentric with the recess 20a. The diameter of the cross section of the ink ejection passage 20b is smaller than the diameter of the cross section of the recess 20a. In other words, the area of ​​the cross section of the ink ejection passage 20b is smaller than the area of ​​the cross section of the recess 20a. The thickness of the silicon substrate 30 is, for example, 40 μm or more and 200 μm or less, and is about 50 μm in this embodiment. The depth of the recess 20a is about 40 μm, and the depth of the ink ejection passage 20b is about 10 μm. The diameter of the cross section of the recess 20a is about 92.2 μm, and the diameter of the cross section of the ink ejection passage 20b is about 28.9 μm.

[0229] The adhesion layer 31 is composed of a main adhesion layer 31a and an adhesion layer intrusion portion 31b. The main adhesion layer 31a is formed on the second surface 30b of the silicon substrate 30. The adhesion layer intrusion portion 31b enters the ink ejection passage 20b from the peripheral portion of the ink ejection port 20c in the main adhesion layer 31a, and is formed on the inner circumferential surface of the ink ejection port side end of the ink ejection passage 20b (in FIG. 20, the end of the silicon substrate 30 corresponding to the lowest end of the ejection passage 20b). The adhesion layer 31 covers the second surface 30b of the silicon substrate 30, the inner circumferential surface of the ink ejection port side end of the ink ejection passage 20b, and the corner (edge) where the inner circumferential surface of the ink ejection passage 20b and the second surface 30b of the silicon substrate 30 intersect.

[0230] The water-repellent film 32 is composed of a main water-repellent film 32a and a water-repellent film entry portion 32b. The main water-repellent film 32a is formed on the surface of the main adhesive layer 31a. The water-repellent film entry portion 32b extends from the peripheral portion of the ink ejection port 20c in the main water-repellent film 32a along the surface of the adhesive layer entry portion 31b, and a portion of it enters the ink ejection passage 20b. The water-repellent film 32 covers the surface of the adhesive layer 31 opposite to the silicon substrate 30.

[0231] The adhesion layer 31 is a layer provided to enhance adhesion of the water-repellent film 32 to the silicon substrate 30, and is made of an oxide film or the like. In this embodiment, the adhesion layer 31 is made of a silicon oxide film (SiOC film) containing carbon (C). The water-repellent film 32 is formed to maintain the mechanicus M in an appropriate state. In this embodiment, the water-repellent film 32 is made of an FDTS film (perfluorodecyltrichlorosilane film). The water-repellent film 32 may be a perfluorooctyltrichlorosilane film.

[0232] The thickness of the adhesion layer 31 is, for example, 100 Å (10 nm) to 200 Å (20 nm), and in this embodiment, approximately 150 Å (15 nm). The thickness of the water-repellent film 32 is, for example, 30 Å (3 nm) to 80 Å (8 nm), and in this embodiment, approximately 50 Å (5 nm). The thickness of the laminated film of the adhesion layer 31 and the water-repellent film 32 is, for example, 100 Å (10 nm) to 300 Å (30 nm). The penetration length L of the portion of the water-repellent film penetration part 32b penetrating the ink ejection passage 20b is preferably 0.1 μm to 3 μm.

[0233] When a change in the volume of the pressure chamber 7 occurs, the ink stored in the pressure chamber 7 passes through the ink discharge passage 20b and is discharged from the ink discharge port 20c.

[0234] 19, the ceiling wall portion of the pressure chamber 7 in the movable film formation layer 10 constitutes a movable film 10A. The movable film 10A (movable film formation layer 10) is made of, for example, silicon oxide (SiO 2In this specification, the movable film 10A refers to the top wall portion of the movable film formation layer 10 that defines the top surface of the pressure chamber 7. Therefore, the portion of the movable film formation layer 10 other than the top wall portion of the pressure chamber 7 does not constitute the movable film 10A.

[0235] The thickness of the movable film 10A is, for example, 0.4 μm to 2 μm. When the movable film 10A is made of a silicon oxide film, the thickness of the silicon oxide film may be about 1.2 μm.

[0236] The pressure chamber 7 is defined by the movable film 10A, the actuator substrate 2, and the nozzle substrate 3, and in this embodiment is formed in a substantially rectangular parallelepiped shape. The length of the pressure chamber 7 may be, for example, about 800 μm, and its width may be about 55 μm. The ink inlet portion 6 communicates with one end of the pressure chamber 7 in the longitudinal direction.

[0237] A metal barrier film 8 is formed on the surface of the movable film formation layer 10. The metal barrier film 8 is, for example, Al 2 O 3 (alumina). The metal barrier film 8 has a thickness of about 50 nm to 100 nm. The piezoelectric element 9 is disposed above the metal barrier film 8 and above the movable film 10A. The piezoelectric element 9 includes a lower electrode 11 formed on the metal barrier film 8, a piezoelectric film 12 formed on the lower electrode 11, and an upper electrode 13 formed on the piezoelectric film 12. In other words, the piezoelectric element 9 is configured by sandwiching the piezoelectric film 12 between the upper electrode 13 and the lower electrode 11 from above and below.

[0238] The upper electrode 13 may be a single film of platinum (Pt) or, for example, a conductive oxide film (e.g., IrO 2 The upper electrode 13 may have a laminated structure in which a metal film (for example, an Ir (iridium oxide) film) and a metal film (for example, an Ir (iridium) film) are laminated. The thickness of the upper electrode 13 may be, for example, about 0.2 μm.

[0239] The piezoelectric film 12 is, for example, a PZT (PbZrx Ti 1-x O 3 A lead zirconate titanate (PZT) film can be applied. Such a piezoelectric film 12 is made of a sintered body of metal oxide crystal. The piezoelectric film 12 is formed in the same shape as the upper electrode 13 in a plan view. The thickness of the piezoelectric film 12 is about 1 μm. It is preferable that the total thickness of the movable film 10A is about the same as the thickness of the piezoelectric film 12 or about 2 / 3 of the thickness of the piezoelectric film 12. The above-mentioned metal barrier film 8 mainly prevents metal elements (Pb, Zr, Ti when the piezoelectric film 12 is PZT) from escaping from the piezoelectric film 12, keeps the piezoelectric properties of the piezoelectric film 12 good, and prevents metal from diffusing into the movable film 10A when the piezoelectric film 12 is formed. The metal barrier film 8 also has a function of preventing the properties of the piezoelectric film 12 from deteriorating due to hydrogen reduction.

[0240] The lower electrode 11 has a two-layer structure in which, for example, a Ti (titanium) film and a Pt (platinum) film are laminated in this order from the metal barrier film 8 side. Alternatively, the lower electrode 11 can be formed of a single film such as an Au (gold) film, a Cr (chromium) layer, or a Ni (nickel) layer. The lower electrode 11 has a main electrode portion 11A in contact with the lower surface of the piezoelectric film 12, and an extension portion 11B extending to an area outside the piezoelectric film 12. The thickness of the lower electrode 11 may be, for example, about 0.2 μm.

[0241] A hydrogen barrier film 14 is formed on the piezoelectric element 9, the extension 11B of the lower electrode 11, and the metal barrier film 8. The hydrogen barrier film 14 is made of, for example, Al 2 O 3 The hydrogen barrier film 14 is made of alumina. The thickness of the hydrogen barrier film 14 is about 50 nm to 100 nm. The hydrogen barrier film 14 is provided to prevent the characteristics of the piezoelectric film 12 from deteriorating due to reduction by hydrogen.

[0242] An insulating film 15 is laminated on the hydrogen barrier film 14. The insulating film 15 is, for example, SiO 2, low hydrogen SiN, etc. The thickness of the insulating film 15 is about 500 nm. On the insulating film 15, an upper wiring 17 and a lower wiring 18 (see FIG. 17 and FIG. 24) are formed. These wirings may be made of a metal material containing Al (aluminum). The thickness of these wirings is, for example, about 1000 nm (1 μm).

[0243] One end of the upper wiring 17 is disposed above one end (the downstream end in the ink flow direction 41) of the upper electrode 13. A contact hole 33 is formed between the upper wiring 17 and the upper electrode 13, continuously penetrating the hydrogen barrier film 14 and the insulating film 15. One end of the upper wiring 17 enters the contact hole 33 and is connected to the upper electrode 13 within the contact hole 33. The upper wiring 17 extends from above the upper electrode 13 across the outer edge of the pressure chamber 7 to the outside of the pressure chamber 7. The lower wiring 18 will be described later.

[0244] A passivation film 21 is formed on the insulating film 15 to cover the upper wiring 17, the lower wiring 18, and the insulating film 15. The passivation film 21 is made of, for example, SiN (silicon nitride). The thickness of the passivation film 21 may be, for example, about 800 nm.

[0245] A pad opening 35 exposing a part of the upper wiring 17 is formed in the passivation film 21. The pad opening 35 is formed in an outer region of the pressure chamber 7, for example, at the tip of the upper wiring 17 (the end opposite to the contact portion to the upper electrode 13). An upper electrode pad 42 covering the pad opening 35 is formed on the passivation film 21. The upper electrode pad 42 enters the pad opening 35 and is connected to the upper wiring 17 within the pad opening 35. A lower electrode pad 43 (see FIGS. 17 and 24) is also provided for the lower wiring 18, but the lower electrode pad 43 will be described later.

[0246] An ink supply through hole 22 is formed at a position corresponding to the end of the ink flow path 5 on the ink inflow section 6 side, penetrating the passivation film 21, insulating film 15, hydrogen barrier film 14, lower electrode 11, metal barrier film 8 and movable film formation layer 10. A through hole 23 including the ink supply through hole 22 and larger than the ink supply through hole 22 is formed in the lower electrode 11. The hydrogen barrier film 14 fills the gap between the through hole 23 of the lower electrode 11 and the ink supply through hole 22. The ink supply through hole 22 communicates with the ink inflow section 6.

[0247] The protective substrate 4 is made of, for example, a silicon substrate. The protective substrate 4 is disposed on the substrate assembly SA so as to cover the piezoelectric element 9. The protective substrate 4 is bonded to the substrate assembly SA via an adhesive 50. The protective substrate 4 has an accommodating recess 52 on an opposing surface 51 that faces the substrate assembly SA. The piezoelectric element 9 is accommodated in the accommodating recess 52. Furthermore, the protective substrate 4 is formed with an ink supply path 53 that communicates with the ink supply through hole 22 and an opening 54 for exposing the pads 42, 43. The ink supply path 53 and the opening 54 penetrate the protective substrate 4. An ink tank (not shown) that stores ink is disposed on the protective substrate 4.

[0248] The piezoelectric element 9 is formed at a position facing the pressure chamber 7 across the movable film 10A and the metal barrier film 8. In other words, the piezoelectric element 9 is formed so as to contact the surface of the metal barrier film 8 on the opposite side to the pressure chamber 7. The pressure chamber 7 is filled with ink by being supplied with ink from the ink tank through the ink supply path 53, the ink supply through hole 22, and the ink inlet portion 6. The movable film 10A defines the top surface of the pressure chamber 7 and faces the pressure chamber 7. The movable film 10A is supported by the surrounding portion of the pressure chamber 7 in the actuator substrate 2, and has flexibility that allows it to deform in a direction facing the pressure chamber 7 (in other words, in the thickness direction of the movable film 10A).

[0249] The lower wiring 18 (see Figs. 17 and 24) and the upper wiring 17 are connected to a drive circuit (not shown). Specifically, the upper electrode pad 42 and the drive circuit are connected via a connecting metal member (not shown). The lower electrode pad 43 (see Figs. 17 and 24) and the drive circuit are connected via a connecting metal member (not shown). When a drive voltage is applied from the drive circuit to the piezoelectric element 9, the piezoelectric film 12 is deformed by the inverse piezoelectric effect. This causes the piezoelectric element 9 and the movable film 10A to deform, which changes the volume of the pressure chamber 7 and pressurizes the ink in the pressure chamber 7. The pressurized ink passes through the ink discharge passage 20b and is discharged as microdroplets from the ink discharge port 20c.

[0250] The configuration of the inkjet printhead 1 will be described in more detail with reference to Figures 16 to 24. In the following description, the left side of Figure 16 will be referred to as "left", the right side of Figure 16 will be referred to as "right", the lower side of Figure 16 will be referred to as "front", and the upper side of Figure 16 will be referred to as "rear".

[0251] 16, the inkjet printhead 1 has a rectangular shape that is long in the front-rear direction in a plan view. In this embodiment, the planar shapes and sizes of the actuator substrate 2, protection substrate 4 and nozzle substrate 3 are approximately the same as those of the inkjet printhead 1.

[0252] On the actuator substrate 2, a plurality of rows of piezoelectric elements 9 (hereinafter referred to as "piezoelectric element rows") are arranged in a stripe pattern at intervals in the front-rear direction in a plan view, and a plurality of rows are provided at intervals in the left-right direction on the actuator substrate 2. In this embodiment, for the sake of convenience of explanation, it is assumed that two rows of piezoelectric elements are provided.

[0253] 17 and 18, an ink flow path 5 (pressure chamber 7) is formed for each piezoelectric element 9 on the actuator substrate 2. Therefore, in plan view, the actuator substrate 2 is provided with two ink flow path rows (pressure chamber rows) spaced apart in the left-right direction, each row being made up of a plurality of ink flow paths 5 (pressure chambers 7) arranged in stripes at intervals in the front-rear direction.

[0254] The pattern of the ink flow path array corresponding to the piezoelectric element array on the left side of Fig. 16 and the pattern of the ink flow path array corresponding to the piezoelectric element array on the right side are symmetrical with respect to the line segment connecting the centers between those arrays. Therefore, in the ink flow paths 5 included in the ink flow path array on the left side, the ink inlet portion 6 is on the right side of the pressure chamber 7, whereas in the ink flow paths 5 included in the ink flow path array on the right side, the ink inlet portion 6 is on the left side of the pressure chamber 7. Therefore, the ink flow directions 41 are opposite to each other in the ink flow path array on the left side and the ink flow path array on the right side.

[0255] An ink supply through hole 22 is provided for each of the multiple ink flow paths 5 in each ink flow path row. The ink supply through hole 22 is disposed on the ink inflow section 6. Therefore, the ink supply through hole 22 for the ink flow path 5 included in the left ink flow path row is disposed on the right end of the ink flow path 5, and the ink supply through hole 22 for the ink flow path 5 included in the right ink flow path row is disposed on the left end of the ink flow path 5.

[0256] In each ink flow path row, the ink flow paths 5 are formed at equal intervals in the width direction with a small interval (for example, about 30 μm to 350 μm). Each ink flow path 5 extends in an elongated shape along the ink flow direction 41. The ink flow path 5 includes an ink inlet section 6 communicating with the ink supply through hole 22 and a pressure chamber 7 communicating with the ink inlet section 6. The pressure chamber 7 has an elongated rectangular shape extending along the ink flow direction 41 in a plan view. That is, the top surface of the pressure chamber 7 has two side edges along the ink flow direction 41 and two end edges along a direction perpendicular to the ink flow direction 41. The ink inlet section 6 has approximately the same width as the pressure chamber 7 in a plan view. The inner surface of the end of the ink inlet section 6 opposite to the pressure chamber 7 is formed in a semicircular shape in a plan view. The ink supply through hole 22 has a circular shape in a plan view (see FIG. 18 in particular).

[0257] In a plan view, the piezoelectric element 9 has a rectangular shape that is long in the longitudinal direction of the pressure chamber 7 (movable membrane 10A). The longitudinal length of the piezoelectric element 9 is shorter than the longitudinal length of the pressure chamber 7 (movable membrane 10A). As shown in FIG. 18, both end edges along the lateral direction of the piezoelectric element 9 are disposed inside the corresponding end edges of the movable membrane 10A with a predetermined interval therebetween. In addition, the width of the piezoelectric element 9 in the lateral direction is narrower than the width of the movable membrane 10A in the lateral direction. Both side edges along the longitudinal direction of the piezoelectric element 9 are disposed inside the corresponding side edges of the movable membrane 10A with a predetermined interval therebetween.

[0258] The lower electrode 11 is formed on almost the entire surface of the movable film formation layer 10 except for the peripheral portion of the surface of the movable film formation layer 10. The lower electrode 11 is a common electrode shared by a plurality of piezoelectric elements 9. The lower electrode 11 includes a main electrode portion 11A having a rectangular shape in a plan view that constitutes the piezoelectric element 9, and an extension portion 11B that is drawn out from the main electrode portion 11A in a direction along the surface of the movable film formation layer 10 and extends outward from the peripheral portion of the top surface of the pressure chamber 7.

[0259] The length of the main electrode portion 11A in the longitudinal direction is shorter than the length of the movable film 10A in the longitudinal direction. Both end edges of the main electrode portion 11A are disposed inwardly with a predetermined interval from the corresponding end edges of the movable film 10A. The width of the main electrode portion 11A in the lateral direction is narrower than the width of the movable film 10A in the lateral direction. Both side edges of the main electrode portion 11A are disposed inwardly with a predetermined interval from the corresponding side edges of the movable film 10A. The extension portion 11B is the entire area of ​​the lower electrode 11 excluding the main electrode portion 11A.

[0260] The upper electrode 13 is formed in a rectangular shape in the same pattern as the main electrode portion 11A of the lower electrode 11 in a plan view. That is, the longitudinal length of the upper electrode 13 is shorter than the longitudinal length of the movable film 10A. Both end edges of the upper electrode 13 are disposed inside the corresponding end edges of the movable film 10A with a predetermined gap therebetween. In addition, the lateral width of the upper electrode 13 is narrower than the lateral width of the movable film 10A. Both end edges of the upper electrode 13 are disposed inside the corresponding end edges of the movable film 10A with a predetermined gap therebetween.

[0261] The piezoelectric film 12 is formed in a rectangular shape in the same pattern as the upper electrode 13 in a plan view. That is, the length of the piezoelectric film 12 in the longitudinal direction is shorter than the length of the movable film 10A in the longitudinal direction. Both end edges of the piezoelectric film 12 are arranged on the inside with a predetermined interval from the corresponding end edges of the movable film 10A. In addition, the width of the piezoelectric film 12 in the lateral direction is narrower than the width of the movable film 10A in the lateral direction. Both side edges of the piezoelectric film 12 are arranged on the inside with a predetermined interval from the corresponding both side edges of the movable film 10A. The lower surface of the piezoelectric film 12 is in contact with the upper surface of the main electrode portion 11A of the lower electrode 11, and the upper surface of the piezoelectric film 12 is in contact with the lower surface of the upper electrode 13.

[0262] The upper wiring 17 extends from the upper surface of one end of the piezoelectric element 9 (the end on the downstream side in the ink flow direction 41) along the end face of the piezoelectric element 9 connected thereto, and further extends in the ink flow direction 41 along the surface of the extension part 11B of the lower electrode 11. The tip of the upper wiring 17 is disposed within the opening 54 of the protection substrate 4.

[0263] The passivation film 21 has an upper electrode pad opening 35 that exposes the center of the tip surface of the upper wiring 17. An upper electrode pad 42 is provided on the passivation film 21 so as to cover the upper electrode pad opening 35. The upper electrode pad 42 is connected to the upper wiring 17 within the upper electrode pad opening 35. The upper electrode pads 42 corresponding to the piezoelectric elements 9 in the left piezoelectric element row are arranged in a line in the front-rear direction on the left side of the left piezoelectric element row in a plan view, as shown in FIG. 16. The upper electrode pads 42 corresponding to the piezoelectric elements 9 in the right piezoelectric element row are arranged in a line in the front-rear direction on the right side of the right piezoelectric element row in a plan view.

[0264] 16, 17, 18 and 24, the lower wiring 18 is disposed at the rear of the left row of pads for the upper electrode and at the rear of the right row of pads for the upper electrode in a plan view. The lower wiring 18 has a rectangular shape in a plan view. An extension 11B of the lower electrode 11 exists below the lower wiring 18. A contact hole 34 is formed between the lower wiring 18 and the extension 11B of the lower electrode 11, continuously penetrating the hydrogen barrier film 14 and the insulating film 15. The lower wiring 18 enters the contact hole 34 and is connected to the extension 11B of the lower electrode 11 within the contact hole 34.

[0265] A pad opening 36 exposing the center of the surface of the lower wiring 18 is formed in the passivation film 21. A lower electrode pad 43 covering the pad opening 36 is formed on the passivation film 21. The lower electrode pad 43 enters the pad opening 36 and is connected to the lower wiring 18 within the pad opening 36.

[0266] As shown in FIG. 16, FIG. 17, and FIG. 19, the protective substrate 4 is formed with a plurality of ink supply paths 53 (hereinafter sometimes referred to as "first ink supply paths 53") communicating with a plurality of ink supply through holes 22 for the left ink flow path row, and a plurality of ink supply paths 53 (hereinafter sometimes referred to as "second ink supply paths 53") communicating with a plurality of ink supply through holes 22 for the right ink flow path row. The first ink supply paths 53 are arranged in a line at a position shifted to the left with respect to the center of the width of the protective substrate 4 in a plan view, with a gap therebetween in the front-rear direction. The second ink supply paths 53 are arranged in a line at a position shifted to the right with respect to the center of the width of the protective substrate 4 in a plan view, with a gap therebetween in the front-rear direction. The ink supply paths 53 are circular in a plan view, with the same pattern as the ink supply through holes 22 on the actuator substrate 2 side. The ink supply paths 53 are aligned with the ink supply through holes 22 in a plan view.

[0267] Moreover, openings 54 are formed in the protective substrate 4 for exposing all of the upper electrode pads 42 corresponding to the left-side piezoelectric element row and the left-side lower electrode pads 43. Moreover, openings 54 are formed in the protective substrate 4 for exposing all of the upper electrode pads 42 corresponding to the right-side piezoelectric element row and the right-side lower electrode pads 43. These openings 54 are rectangular in shape that is long in the front-rear direction in a plan view.

[0268] FIG. 27 is a bottom view of the area of ​​the protection substrate shown in FIG.

[0269] 19, 23 and 27, an accommodating recess 52 is formed on an opposing surface 51 of a protective substrate 4 at a position facing a piezoelectric element 9 in each piezoelectric element row. An ink supply path 53 is disposed on the upstream side of each accommodating recess 52 in the ink flow direction 41, and an opening 54 is disposed on the downstream side. Each accommodating recess 52 is formed in a rectangular shape slightly larger than the pattern of the upper electrode 13 of the corresponding piezoelectric element 9 in a plan view. A corresponding piezoelectric element 9 is accommodated in each accommodating recess 52.

[0270] FIG. 25 is a schematic plan view showing an example of a pattern of an insulating film of the inkjet print head. FIG. 26 is a schematic plan view showing an example of a pattern of a passivation film of the inkjet print head.

[0271] In this embodiment, the insulating film 15 and the passivation film 21 are formed on the actuator substrate 2 over substantially the entire outer region of the accommodation recess 52 of the protection substrate 4 in a plan view. However, in this region, the insulating film 15 is formed with an ink supply through hole 22 and a contact hole 34. In this region, the passivation film 21 is formed with an ink supply through hole 22 and pad openings 35, 36.

[0272] In the inner region of the accommodation recess 52 of the protection substrate 4, the insulating film 15 and the passivation film 21 are formed only at one end (upper wiring region) where the upper wiring 17 is present. In this region, the passivation film 21 is formed so as to cover the upper surface and the side surface of the upper wiring 17 on the insulating film 15. In other words, the insulating film 15 and the passivation film 21 are formed with an opening 37 in the region of the inner region of the accommodation recess 52 in a plan view excluding the upper wiring region. The insulating film 15 is further formed with a contact hole 33.

[0273] An outline of a method for manufacturing the inkjet print head 1 will be described.

[0274] FIG. 28 is a plan view of a semiconductor wafer as a base substrate of the actuator substrate, with a partial region enlarged and shown.

[0275] A semiconductor wafer (actuator wafer) 100 as an original substrate of the actuator substrate 2 is made of, for example, a silicon wafer. A surface 100a of the actuator wafer 100 corresponds to a surface 2a of the actuator substrate. A plurality of functional element forming regions 101 are arranged in a matrix on the surface 100a of the actuator wafer 100. A scribe region (boundary region) 102 is provided between adjacent functional element forming regions 101. The scribe region 102 is a strip-shaped region having a substantially constant width, and is formed in a lattice shape extending in two directions perpendicular to each other. A cutting line 103 is set in the scribe region 102. By performing necessary processes on the actuator wafer 100, a substrate assembly aggregate (SA aggregate) 110 (see FIG. 29J) is created in which the ink flow path 5 is not formed but the configuration of the substrate assembly SA is formed on each functional element forming region 101.

[0276] A protective substrate aggregate 130 (see FIG. 29K) integrally including a plurality of protective substrates 4 corresponding to each functional element formation region 101 of the substrate assembly aggregate 110 is prepared in advance. The protective substrate aggregate 130 is produced by carrying out necessary processes on a semiconductor wafer (protective substrate wafer) serving as an original substrate for the protective substrate 4. The protective substrate wafer is made of, for example, a silicon wafer.

[0277] Also, a nozzle substrate aggregate 150 (see FIG. 29M and FIG. 30E) integrally including a plurality of nozzle substrates 3 corresponding to each functional element formation region 101 of the substrate assembly aggregate 110 is prepared in advance. The nozzle substrate aggregate 150 is produced by carrying out necessary processes on a semiconductor wafer (nozzle wafer) as an original substrate of the nozzle substrate 3. The nozzle wafer is made of, for example, a silicon wafer. As shown in FIG. 29M and FIG. 30E, the nozzle substrate aggregate 150 is made of a nozzle wafer 140, an adhesion material film 141 which is a material film of the adhesion layer 31 formed on a part of the exposed surface of the nozzle wafer 140, and a water-repellent material film 142 which is a material film of the water-repellent film 32 formed on the surface of the adhesion material film 141.

[0278] After the substrate assembly aggregate 110 is created, the protective substrate aggregate 130 is bonded to the substrate assembly aggregate 110. Next, an ink flow path 5 is formed in the substrate assembly aggregate 110. Next, the nozzle substrate aggregate 150 is bonded to the substrate assembly aggregate 110. As a result, an inkjet printhead aggregate 170 (see FIG. 29M) consisting of the substrate assembly aggregate 110, the protective substrate aggregate 130, and the nozzle substrate aggregate 150 is obtained. After that, the inkjet printhead aggregate 170 is cut (diced) along the cutting lines 103 (see FIG. 28) by a dicing blade. As a result, individual inkjet printheads (chips) 1 including functional element forming regions 101 are cut out. The inkjet printhead 1 has a scribe region 102 on the periphery and has the functional element forming region 101 in the central region surrounded by the scribe region 102 (see FIG. 28).

[0279] A method for manufacturing the inkjet printhead 1 will now be described in detail.

[0280] 29A to 29M are cross-sectional views showing the manufacturing process of the inkjet printhead 1, and correspond to the cross section of FIG.

[0281] First, as shown in Fig. 29A, an actuator wafer 100 is prepared. However, the actuator wafer 100 used is thicker than the final actuator substrate 2. Then, a movable film formation layer 10 is formed on a surface 100a of the actuator wafer 100. Specifically, a silicon oxide film (for example, 1.2 µm thick) is formed on the surface 100a of the actuator wafer 100.

[0282] Next, a metal barrier film 8 is formed on the movable film formation layer 10. The metal barrier film 8 is, for example, Al 2 O 3The metal barrier film 8 is made of a film (for example, 50 nm to 100 nm thick). The metal barrier film 8 prevents metal atoms from escaping from the piezoelectric film 12 to be formed later. If metal electrons escape, the piezoelectric characteristics of the piezoelectric film 12 may deteriorate. Furthermore, if the escaped metal atoms get mixed into the silicon layer that constitutes the movable film 10A, the durability of the movable film 10A may deteriorate.

[0283] 29B, a lower electrode film 71, which is a material layer for the lower electrode 11, is formed on the metal barrier film 8. The lower electrode film 71 is, for example, a Pt / Ti laminated film having a Ti film (for example, 10 nm to 40 nm thick) as a lower layer and a Pt film (for example, 10 nm to 400 nm thick) as an upper layer. Such a lower electrode film 71 may be formed by a sputtering method.

[0284] Next, a piezoelectric material film 72, which is the material of the piezoelectric film 12, is formed on the entire surface of the lower electrode film 71. Specifically, for example, the piezoelectric material film 72 is formed to a thickness of 1 μm to 3 μm by a sol-gel method. Such a piezoelectric material film 72 is made of a sintered body of metal oxide crystal grains.

[0285] Next, an upper electrode film 73, which is the material of the upper electrode 13, is formed on the entire surface of the piezoelectric material film 72. The upper electrode film 73 may be, for example, a single film of platinum (Pt). The upper electrode film 73 may be, for example, IrO 2 A IrO film (for example, 40 nm to 160 nm thick) is used as the lower layer, and an Ir film (for example, 40 nm to 160 nm thick) is used as the upper layer. 2 / Ir laminated film. Such an upper electrode film 73 may be formed by sputtering.

[0286] Next, as shown in Figures 29C and 29D, the upper electrode film 73, the piezoelectric material film 72, and the lower electrode film 71 are patterned. First, a resist mask of the pattern of the upper electrode 13 is formed by photolithography. Then, as shown in Figure 29C, the upper electrode film 73 and the piezoelectric material film 72 are successively etched using this resist mask as a mask, thereby forming the upper electrode 13 and the piezoelectric film 12 in a predetermined pattern.

[0287] Next, after the resist mask is peeled off, a resist mask for the pattern of the lower electrode 11 is formed by photolithography. Then, as shown in FIG. 29D, with this resist mask as a mask, the lower electrode film 71 is etched to form the lower electrode 11 of a predetermined pattern. Thereby, the lower electrode 11 composed of the main electrode portion 11A and the extension portion 11B having the through hole 23 is formed. In this way, the piezoelectric element 9 composed of the main electrode portion 11A of the lower electrode 11, the piezoelectric film 12, and the upper electrode 13 is formed.

[0288] Next, as shown in FIG. 29E, after the resist mask is peeled off, a hydrogen barrier film 14 covering the entire surface is formed. The hydrogen barrier film 14 may be an Al 2 O 3 film, and the film thickness thereof may be 50 nm to 100 nm. Thereafter, an insulating film 15 is formed on the entire surface of the hydrogen barrier film 14. The insulating film 15 may be a SiO 2 film, and the film thickness thereof may be 200 nm to 300 nm. Subsequently, contact holes 33 and 34 are formed by continuously etching the insulating film 15 and the hydrogen barrier film 14. In FIG. 29E, the contact hole 34 is not shown because it is located in the depth direction of the drawing.

[0289] Next, as shown in FIG. 29F, a wiring film constituting the upper wiring 17 and the lower wiring 18 is formed on the insulating film 15 including the inside of the contact holes 33 and 34 by sputtering. Thereafter, the wiring film is patterned by photolithography and etching to simultaneously form the upper wiring 17 and the lower wiring 18. In FIG. 29F, the lower wiring 18 is not shown because it is located in the depth direction of the drawing.

[0290] Next, as shown in FIG. 29G, a passivation film 21 covering each of the wirings 17 and 18 is formed on the surface of the insulating film 15. The passivation film 21 is made of, for example, SiN. The passivation film 21 is formed by, for example, plasma CVD.

[0291] Next, a resist mask having openings corresponding to the pad openings 35, 36 is formed by photolithography, and the passivation film 21 is etched using this resist mask. As a result, the pad openings 35, 36 are formed in the passivation film 21, as shown in Fig. 29H. After the resist mask is peeled off, the upper electrode pad 42 and the lower electrode pad 43 are formed on the passivation film 21 through the pad openings 35, 36, respectively. In Fig. 29H, the pad opening 36 and the lower electrode pad 43 are not shown because they are located toward the back of the drawing.

[0292] Next, a resist mask having openings corresponding to the opening 37 and the ink supply through hole 22 is formed by photolithography, and the passivation film 21 and the insulating film 15 are successively etched using this resist mask. As a result, the opening 37 and the ink supply through hole 22 are formed in the passivation film 21 and the insulating film 15, as shown in FIG. 29I.

[0293] Next, the resist mask is peeled off. Then, a resist mask having an opening corresponding to the ink supply through hole 22 is formed by photolithography, and the hydrogen barrier film 14, the metal barrier film 8, and the movable film formation layer 10 are etched using this resist mask. As a result, as shown in FIG. 29J, the ink supply through hole 22 is formed in the hydrogen barrier film 14, the metal barrier film 8, and the movable film formation layer 10. In this way, the substrate assembly aggregate 110 is produced.

[0294] Next, as shown in FIG. 29K, adhesive 50 is applied to the opposing surface 51 of the protective substrate assembly 130, and the protective substrate assembly 130 is fixed to the substrate assembly assembly 110 so that the ink supply path 53 and the corresponding ink supply through hole 22 are aligned.

[0295] Next, as shown in FIG. 29L, back grinding is performed to thin the actuator wafer 100. The actuator wafer 100 is polished from the back surface 100b, thereby thinning the actuator wafer 100. For example, the actuator wafer 100, which is about 670 μm thick in the initial state, may be thinned to about 75 μm thick. After that, a resist mask having openings corresponding to the ink flow paths 5 (ink inlet portion 6 and pressure chambers 7) is formed on the back surface 100b side of the actuator wafer 100 by photolithography, and the actuator wafer 100 is etched from the back surface 100b using this resist mask. As a result, the ink flow paths 5 (ink inlet portion 6 and pressure chambers 7) are formed in the actuator wafer 100.

[0296] During this etching, the metal barrier film 8 formed on the surface of the movable film formation layer 10 prevents metal elements (Pb, Zr, Ti in the case of PZT) from escaping from the piezoelectric film 12, and maintains good piezoelectric characteristics of the piezoelectric film 12. As described above, the metal barrier film 8 also contributes to maintaining the durability of the silicon layer that forms the movable film 10A.

[0297] Thereafter, as shown in Fig. 29M, the nozzle substrate aggregate 150 is attached to the rear surface 100b of the actuator wafer 100. As a result, an inkjet printhead aggregate 170 is obtained, which is composed of the substrate assembly aggregate 110, the protective substrate aggregate 130, and the nozzle substrate aggregate 150. Thereafter, the inkjet printhead aggregate 170 is cut by a dicing blade along the planned cutting lines 103 (see Fig. 28). In other words, a process is performed to cut out the inkjet printheads 1 individually.

[0298] Upon completion of this process, the actuator wafer 100 in the substrate assembly aggregate 110 becomes the actuator substrate 2 of each inkjet printhead 1. Also, the protective substrate aggregate 130 becomes the protective substrate 4 of each inkjet printhead 1. Also, the nozzle wafer 140, the adhesion material film 141 and the water-repellent material film 142 in the nozzle substrate aggregate 150 become the silicon substrate 30, the adhesion layer 31 and the water-repellent film 32 in the nozzle substrate 3 of each inkjet printhead 1, respectively. In this manner, individual inkjet printheads 1 having the structure shown in FIGS. 16 to 24 are obtained.

[0299] In the inkjet printhead 1 obtained in this manner, the side surfaces of the actuator substrate 2 and the side surfaces of the nozzle substrate 3 are flush in all directions (flat all around) in a plan view. That is, in this embodiment, an inkjet printhead 1 is obtained in which there is no step between the actuator substrate 2 and the nozzle substrate 3. Also, in this embodiment, the side surfaces of the actuator substrate 2 and the side surfaces of the protective substrate 4 are also flush in all directions (flat all around) in a plan view. That is, in this embodiment, an inkjet printhead 1 is obtained in which there is no step between the actuator substrate 2 and the protective substrate 4.

[0300] In the method for manufacturing an inkjet printhead according to this embodiment, a nozzle substrate assembly 150 is bonded to a substrate assembly assembly 110 to which a protective substrate assembly 130 is fixed, thereby producing an inkjet printhead assembly 170. The inkjet printhead assembly 170 is then diced to cut out individual inkjet printheads 1. This allows the inkjet printhead 1 to be manufactured more efficiently than, for example, a case in which an inkjet printhead is manufactured by manufacturing individual substrate assemblies SA and then bonding nozzle substrates 3 to the individual substrate assemblies SA.

[0301] 30A to 30E are cross-sectional views that diagrammatically show the manufacturing process of the nozzle substrate assembly 150. As shown in FIG.

[0302] First, as shown in Fig. 30A, a semiconductor wafer (nozzle wafer) 140 is prepared as the original substrate of the nozzle substrate 3. The nozzle wafer 140 is made of a silicon wafer. The nozzle wafer 140 has a surface (first surface) 140a facing the back surface 2b of the actuator substrate 2, and a back surface (second surface) 140b on the opposite side.

[0303] A resist mask having an opening corresponding to the recess 20a is formed by photolithography, and the nozzle wafer 140 is etched using this resist mask to form the recess 20a on the first surface 140a of the nozzle wafer 140. After this, a cylindrical ink ejection passage 20b is formed by, for example, the Bosch process. The ink ejection passage 20b has an ink ejection port 20c on the second surface 140b side of the nozzle wafer 140. As a result, the nozzle hole 20 consisting of the recess 20a and the ink ejection passage 20b is formed in the nozzle wafer 140. Then, the resist mask is removed.

[0304] Next, as shown in FIG. 30B, an adhesion material film 141, which is a material film of the adhesion layer 31, and a water-repellent material film 142, which is a material film of the water-repellent film 32, are sequentially formed on the entire exposed surface of the nozzle wafer 140, including the first surface 140a and the second surface 140b of the nozzle wafer 140 and the inner surface of the nozzle hole 20. As a result, a laminated film 143 consisting of the adhesion material film 141 and the water-repellent material film 142 is formed on the entire exposed surface of the nozzle wafer 140. The adhesion material film 141 and the water-repellent material film 142 are formed, for example, by CVD (chemical vapor deposition). The adhesion material film 141 and the water-repellent material film 142 may be formed by MCV (Molecular Vapor Deposition) (registered trademark), which is a type of CVD method. In this embodiment, BTCSE (trichlorosilylethane) gas is used to form the adhesion material film 141, and FDTS (perfluorodecyltrichlorosilane) gas is used to form the water-repellent material film 142. The water-repellent material film 142 may be formed using perfluorooctyltrichlorosilane gas.

[0305] 30C, a masking tape 144 is attached to the laminated film 143 formed on the second surface 140b of the nozzle wafer 140 so as to cover the laminated film 143 formed on the second surface 140b of the nozzle wafer 140 and the ink ejection ports 20c. The masking tape 144 is a tape in which an adhesive 144b is applied to one side of a base film 144a. The thickness of the base film 144a is about 115 μm, and the thickness of the adhesive 144b is about 15 μm.

[0306] The step of attaching the masking tape 144 to the second surface 140b of the nozzle wafer 140 is performed by an operator. For example, the operator performs the following operations. First, the tape is pulled out from the roll. Next, the wafer and the tape are brought into close contact with each other. Next, the tape is pressed against the wafer with a roller. Next, the tape is cut into a circle.

[0307] The masking tape 144 is attached to the laminated film 143 so that the adhesive 144b of the masking tape 144 penetrates into the ink ejection port side end of the ink ejection passage 20b. As a result, the laminated film 143 formed on the inner surface of the ink ejection port side end of the ink ejection passage 20b is covered with the adhesive 144b.

[0308] Next, as shown in Fig. 30D, the laminated film 143 is etched by plasma etching using the masking tape 144 as a mask. This removes the laminated film 143 except for a first portion formed on the second surface 140b of the nozzle wafer 140 and a second portion formed on the inner surface of the ink ejection port side end of the ink ejection passage 20b. The first portion corresponds to the laminated film portion consisting of the main adhesive layer 41a and the main water-repellent film 42a in Fig. 20, and the second portion corresponds to the laminated film portion consisting of the adhesive layer inlet portion 41b and the water-repellent film inlet portion 42b in Fig. 20.

[0309] 30D, the portion of the adhesive material film 141 that corresponds to the main adhesive layer 41a is indicated by reference numeral 141a, and the portion that corresponds to the adhesive layer intrusion portion 41b is indicated by reference numeral 141b. Similarly, the portion of the water-repellent material film 142 that corresponds to the main water-repellent film 42a is indicated by reference numeral 142a, and the portion that corresponds to the water-repellent film intrusion portion 42b is indicated by reference numeral 142b.

[0310] Finally, as shown in Fig. 30E, the masking tape 144 is peeled off. This results in a nozzle substrate assembly 150 consisting of the nozzle wafer 140 having the nozzle holes 20, the adhesive material film 141 formed in a predetermined region of the exposed surface of the nozzle wafer 140, and the water-repellent material film 142 formed on the surface of the adhesive material film 141 opposite to the nozzle wafer 140.

[0311] The nozzle substrate aggregate 150 obtained in this manner is attached to the rear surface 100 b of the actuator wafer 100 of the substrate assembly aggregate 110 .

[0312] In this embodiment, the adhesion layer 31 has a main adhesion layer 31a formed on the second surface 30b of the silicon substrate 30, and an adhesion layer intrusion portion 31b that enters the ink ejection passage 20b from the peripheral portion of the ink ejection orifice 20c in the main adhesion layer 31 and is formed on the inner surface of the ink ejection orifice side end of the ink ejection passage 20b. The water-repellent film 32 has a main water-repellent film 32a formed on the surface of the main adhesion layer 31, and a water-repellent film intrusion portion 32b that extends from the peripheral portion of the ink ejection orifice 20c in the main water-repellent film 32a along the surface of the adhesion layer intrusion portion 31b and partially intrudes into the ink ejection passage 20b.

[0313] When the second surface 30b of the silicon substrate 30 is wiped by the wiping mechanism, the main water-repellent film 32a formed on the second surface 30b may deteriorate. However, even if the second surface 30b of the silicon substrate 30 is wiped by the wiping mechanism, the portion of the water-repellent film entry portion 32b that enters the ink ejection passage 20b is not wiped by the wiping mechanism, and therefore the portion is unlikely to deteriorate. Therefore, compared to the conventional example described in Patent Document 1, the contact angle and contact circumference of the meniscus with respect to the inner surface of the nozzle hole are unlikely to change. This makes it possible to suppress changes in the ink ejection performance.

[0314] As already mentioned, the penetration length L of the portion of the water-repellent film penetration part 32b that penetrates the ink ejection passage 20b is preferably 0.1 μm or more and 3 μm or less. If the penetration length L exceeds 3 μm, it is not preferable because it affects the volume of one droplet of ink that is ejected as a microdroplet from the ink ejection port 20c by pressure. If the penetration length L is less than 0.1 μm, it is not preferable because the water-repellent film penetration part 32b may be adversely affected by the wiping mechanism.

[0315] Although the embodiment of the fourth disclosure has been described above, the fourth disclosure can be embodied in other embodiments. In the above-described embodiment, the recess 20a is formed in a cylindrical shape, but as shown in Fig. 31, it may be formed in a truncated cone shape whose cross section gradually becomes smaller from the first surface 30a to the second surface 30b of the silicon substrate 30. The ink ejection passage 20b is cylindrical and concentric with the recess 20a. Note that Fig. 31 is a cross-sectional view corresponding to the cut surface of Fig. 20.

[0316] Furthermore, although two rows of piezoelectric elements (rows of pressure chambers) are provided on the actuator substrate 2, only one row of piezoelectric elements (rows of pressure chambers) may be provided, or three or more rows of piezoelectric elements (rows of pressure chambers) may be provided.

[0317] In the above embodiment, the insulating film 15 is formed on a portion of the surface of the hydrogen barrier film 14, but the insulating film 15 may be formed on the entire surface of the hydrogen barrier film 14.

[0318] In the above embodiment, the insulating film 15 is formed on part of the surface of the hydrogen barrier film 14, but the insulating film 15 may be omitted.

[0319] In the above embodiment, PZT is used as an example of the material of the piezoelectric film. However, other materials such as lead titanate (PbPO 3 ), potassium niobate (KNbO 3 ), lithium niobate (LiNbO 3 ), lithium tantalate (LiTaO 3 Alternatively, a piezoelectric material made of a metal oxide such as SiO 2 may be used.

[0320] Although the embodiments of the present disclosure have been described in detail, these are merely specific examples used to clarify the technical content of the present disclosure, and the present disclosure should not be interpreted as being limited to these specific examples, and the scope of the present disclosure is limited only by the appended claims.

[0321] This application corresponds to Patent Application Nos. 2020-120873, 2020-120871, and 2020-120872 filed with the Japan Patent Office on July 14, 2020, and Patent Application No. 2020-157862 filed with the Japan Patent Office on September 18, 2020, the entire disclosures of which are incorporated herein by reference. [Explanation of symbols]

[0322] 1 Inject print head 2 Actuator Board 2a surface 2b Back side 3 Nozzle Board 3a Nozzle hole 3b Ink outlet 4 Protection Board 4a Oxide film 5 Movable membrane forming layer 5A Movable membrane 6 Ink flow path 7 Ink inlet 8. Pressure Chamber 9 Ink Outlet 10 Piezoelectric element 11 Lower electrode 11A main electrode section 11B Extension 12 Piezoelectric film 13 Upper electrode 21 First hydrogen barrier film 22 Second hydrogen barrier film 22a Outer edge 23 Hydrogen Barrier Film 24 Interlayer insulating film 25 First interlayer insulating film 26 Second interlayer insulating film 27 Upper Wiring 27A 1st upper contact 27B Second upper contact part 27C Upper connection wire 27D Upper pad 28 Lower Wiring 28A Lower Contact 28B Lower connection wire 28C Lower pad 29 Dummy wiring 30 Passivation film 31 First wetted film 35 Aperture 41 First upper contact hole 42 Second upper contact hole 43 Lower contact hole 44 Upper pad opening 45 Lower pad opening 50 Ink flow direction 51 Upper electrode pad 52 Lower electrode pad 53 First ink inlet passage 54 First ink outlet passage 61 Adhesion-strengthening film 62 Adhesive layer 63 Adhesive layer 65 Second wetted membrane 66 Water-repellent film 71 Opposite Surface 72 Storage Recess 73 Second ink inlet passage 74 Second ink outlet passage 75 First opening 76 Second Opening 81 Lower electrode film 82 Piezoelectric material film 83 Upper electrode film 84 Wiring film 85 Metal Film 86 Resist Mask 87 Adhesive material layer 100 Actuator Wafer 100a Surface 100b back side 101 Functional element formation area 102 Scribe Area 103 Cutting line 110 Substrate assembly assembly 130 Protection board assembly 140 Nozzle Wafer 150 Nozzle substrate assembly 170 Inkjet printhead assembly SA Board Assembly

Claims

1. an actuator substrate having an ink flow path including a pressure chamber; a movable film forming layer including a movable film disposed above the pressure chamber and defining a top surface of the pressure chamber; a piezoelectric element including a lower electrode disposed on the movable film, a piezoelectric film formed on the lower electrode, and an upper electrode formed on the piezoelectric film; a hydrogen barrier film covering at least the entire side surfaces of the upper electrode, the piezoelectric film and the lower electrode, at least a portion of the upper surface of the upper electrode, and the upper surface of the lower electrode, among the surfaces of the piezoelectric element; a first interlayer insulating film formed on a surface of the hydrogen barrier film excluding an end surface; a second interlayer insulating film formed so as to cover an end surface of the hydrogen barrier film and the first interlayer insulating film; and a wiring formed on the second interlayer insulating film and connected to the piezoelectric element.

2. The ink-jet printhead of claim 1 , wherein the lower electrode includes a main electrode portion in contact with a lower surface of the piezoelectric film, and an extension portion extending outward from the main electrode portion to the outside of the piezoelectric film.

3. The inkjet printhead of claim 1 , wherein the wiring includes an upper wiring connected to the upper electrode and a lower wiring connected to the lower electrode.

4. an upper contact hole exposing a part of an upper surface of the upper electrode is formed in the hydrogen barrier film, the first interlayer insulating film, and the second interlayer insulating film formed on the upper surface of the upper electrode, and one end of the upper wiring is connected to the upper electrode through the upper contact hole; 4. The inkjet printhead of claim 3, wherein a lower contact hole exposing a portion of the upper surface of the lower electrode is formed in the hydrogen barrier film, the first interlayer insulating film, and the second interlayer insulating film formed on the upper surface of the lower electrode, and one end of the lower wiring is connected to the lower electrode via the lower contact hole.

5. 5. The inkjet printhead according to claim 1, wherein the hydrogen barrier film is also formed on a lower surface of the lower electrode.

6. 6. The inkjet printhead according to claim 1, further comprising a passivation film formed on the second interlayer insulating film and covering the wiring.

7. When viewed in a plan view from a direction normal to a main surface of the movable film, a top surface portion of the pressure chamber has a rectangular shape that is long in a predetermined first direction, An inkjet printhead as described in any one of claims 1 to 6, wherein the upper electrode and the piezoelectric film are rectangular in shape and elongated in the first direction, and have a peripheral edge that is recessed further inward into the pressure chamber than the movable film.

8. The lower electrode has a rectangular shape that is long in the first direction in the plan view, a longitudinal length of the lower electrode is longer than a longitudinal length of the piezoelectric film and shorter than a longitudinal length of the movable film; both end edges of the lower electrode are spaced apart from and inwardly spaced from the corresponding end edges of the movable film, the length of the lower electrode in the short-side direction is longer than the length of the piezoelectric film in the short-side direction and longer than the length of the movable film in the short-side direction; 8. The ink jet printhead of claim 7, wherein opposite side edges of the bottom electrode are spaced outwardly from corresponding side edges of the movable membrane.

9. A plurality of the pressure chambers are provided, The piezoelectric element is provided for each of the pressure chambers, 9. The inkjet printhead according to claim 7, wherein the actuator substrate has a plurality of pressure chamber rows, each row being spaced apart in a second direction perpendicular to the first direction when viewed in the plane, the pressure chamber rows being spaced apart in the first direction.

10. a nozzle substrate which is bonded to a surface of the actuator substrate opposite to the movable membrane side, which defines a bottom portion of the pressure chamber and has a nozzle hole communicating with the pressure chamber; a protection substrate disposed on the opposite side of the actuator substrate from the nozzle substrate and bonded to the actuator substrate so as to cover the piezoelectric element; 10. The inkjet printhead according to claim 1, wherein the protection substrate has an accommodating recess that opens toward the actuator substrate and accommodates the piezoelectric element, and an ink passage that communicates with the ink flow path.

11. forming a first hydrogen barrier material film, a lower electrode film, a piezoelectric material film, and an upper electrode film in this order on a substrate; a step of patterning the upper electrode film and the piezoelectric material film into an upper electrode pattern to form an upper electrode and a piezoelectric film; patterning the bottom electrode film and the first hydrogen barrier material film into a bottom electrode pattern to form a bottom electrode and a first hydrogen barrier film; forming a second hydrogen barrier material film covering the entire surface of the substrate, and then forming a first interlayer insulating material film on the entire surface of the second hydrogen barrier material film; patterning the second hydrogen barrier material film and the first interlayer insulating material film into a predetermined second hydrogen barrier film pattern to form a second hydrogen barrier film and a first interlayer insulating film; forming a second interlayer insulating film covering the second hydrogen barrier film and the first interlayer insulating film on the substrate; forming an upper wiring, one end of which is connected to the upper electrode, and a lower wiring, one end of which is connected to the lower electrode, on the second interlayer insulating film.

12. The wiring forming step includes: forming contact holes which continuously penetrate the second interlayer insulating film, the first interlayer insulating film, and the second hydrogen barrier film, the contact holes exposing a portion of an upper surface of the upper electrode and a lower contact hole exposing a portion of an upper surface of the lower electrode; forming a wiring film on the second interlayer insulating film including inside the upper contact hole and the lower contact hole; The method of claim 11, further comprising forming the upper wiring and the lower wiring by patterning the wiring film.

13. The method of claim 11 or 12, further comprising the step of forming a passivation film covering the upper wiring and the lower wiring on a surface of the second interlayer insulating film after the wiring forming step.

Images