JP2015208882A - Liquid discharge device, image formation apparatus and manufacturing method of liquid discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge device which can suppress deterioration in the displacement characteristics of a piezoelectric element due to damage in a function of a protective film of preventing the piezoelectric element from contacting moisture in the air.SOLUTION: A liquid discharge device comprises: a nozzle plate having a nozzle hole for discharging liquid such as ink; a compression liquid chamber 202 which communicates with the nozzle hole; a diaphragm 203 which constitutes a part of the compression liquid chamber; a piezoelectric element 201 which is coated with a protective film 204 and generates pressure change in the compression liquid chamber by applying vibration to the diaphragm; and a signal wiring 205 which transmits a drive signal from an external drive circuit to a prescribed site of the piezoelectric element. The protective film 204 coating the piezoelectric element includes: a moisture resistance layer 204a; and a protective layer 204b for moisture resistance layer which is formed on the upper layer than the moisture resistance layer and protects the moisture resistance layer against damage in a process of removing from the protective film the unnecessary portion of an insulator film 213 insulating the space between the signal wiring and a portion other than the prescribed site of the piezoelectric element.

Description

  The present invention relates to a liquid ejection apparatus, an image forming apparatus, and a method for manufacturing the liquid ejection apparatus.

  In this type of liquid ejection device, a piezoelectric element that applies vibration to a diaphragm is driven by a drive signal transmitted from a signal wiring to generate a pressure change in the pressurized liquid chamber, and the liquid in the pressurized liquid chamber is What is discharged from a hole is known.

  Patent Document 1 discloses an ink jet head (liquid ejecting apparatus) in which a protective film that covers a piezoelectric element is formed for the purpose of preventing deterioration of characteristics of the piezoelectric element due to moisture. In Patent Document 1, a highly flexible resin layer is used for a protective film portion that covers the upper surface of the piezoelectric element in order to suppress a decrease in ejection performance due to the displacement of the piezoelectric element being restricted by the protective film. It is described.

  In a method for manufacturing a liquid ejection device, generally, a piezoelectric element including a lower electrode layer, a piezoelectric layer, and an upper electrode layer is formed on a vibration plate, and then a protective film is formed so as to cover the piezoelectric element. This protective film is for preventing the displacement characteristics from deteriorating when the piezoelectric element comes into contact with moisture in the air. After forming this protective film, an insulating film is formed on the protective film, and then a predetermined portion of the protective film and the insulating film is removed to form a contact hole to expose the upper electrode layer of the piezoelectric element. Then, a signal wiring for transmitting a drive signal to the upper electrode layer of the piezoelectric element through the contact hole is formed on the insulating film. Thereby, a drive signal can be applied to a predetermined portion of the upper electrode layer of the piezoelectric element.

  The insulating film formed in this way is for ensuring insulation between the signal wiring and the upper electrode layer of the piezoelectric element at a place other than the contact hole. The portion that does not contribute to the insulation between the layers is unnecessary. In addition, if the insulating film is present over a large area on the piezoelectric element, it causes a harmful effect of inhibiting the displacement of the piezoelectric element. For this reason, this insulating film is usually subjected to an insulating film removing process such as a dry etching process so that a portion not contributing to the insulation between the signal wiring and the upper electrode layer of the piezoelectric element is removed from the region on the piezoelectric element. The

  However, the protective film of the piezoelectric element may be peeled off or lost due to a process damage caused by a medium such as an etching gas used in the insulating film removing process or a phenomenon such as discharge generated in the process. For example, when the insulating film is removed by dry etching, pinhole defects may occur in the protective film due to the influence of discharge or the like during dry etching. When the protective film is damaged in this way, the function of the protective film for preventing the piezoelectric element from coming into contact with moisture in the air is impaired, and the displacement characteristic of the piezoelectric element is likely to deteriorate.

  In order to solve the above-described problems, the present invention provides a nozzle plate having a nozzle hole for discharging a liquid, a pressurized liquid chamber communicating with the nozzle hole, and a vibration plate constituting a part of the pressurized liquid chamber. And a piezoelectric element that is covered with a protective film and applies vibration to the diaphragm to generate a pressure change in the pressurized liquid chamber, and is formed on the protective film of the piezoelectric element, and is formed at a predetermined position of the piezoelectric element. In a liquid ejection apparatus including a signal wiring that transmits a driving signal from an external driving circuit, a protective film that covers the piezoelectric element is formed in a moisture resistant layer and an upper layer than the moisture resistant layer, and the signal wiring A protective layer for a moisture-resistant layer that protects the moisture-resistant layer from being damaged during the step of removing unnecessary portions of the insulating film that insulates the piezoelectric element from portions other than the predetermined portion from the protective film. It is characterized by including.

  According to the present invention, it is difficult to impair the function of the protective film that prevents the piezoelectric element from coming into contact with moisture in the air, and an excellent effect is obtained that the displacement characteristics of the piezoelectric element are not easily deteriorated.

FIG. 3 is a partial cross-sectional view of the actuator substrate constituting the droplet discharge head in the embodiment when cut along the A-A ′ cut surface in FIG. 2. FIG. 3 is an exploded perspective view showing a main configuration of the droplet discharge head. It is sectional drawing of the silicon substrate used as the base of an actuator substrate. It is explanatory drawing of the formation process of a diaphragm. It is explanatory drawing of the formation process of an electrode layer and a PZT film | membrane. It is explanatory drawing of the patterning process of an electrode layer and a PZT film | membrane. It is explanatory drawing of the formation process of an interlayer insulation film. It is explanatory drawing of the formation process of a contact hole. It is explanatory drawing of the formation process of a contact hole. It is explanatory drawing of the formation process of extraction wiring. It is explanatory drawing of the formation process of extraction wiring. It is explanatory drawing of the formation process of a passivation protective film. It is explanatory drawing of the formation process of a passivation protective film. It is explanatory drawing of the grinding | polishing process for liquid chamber formation. It is explanatory drawing of the formation process of a liquid chamber. It is explanatory drawing of the formation process of a liquid chamber. It is sectional drawing of the completed actuator board | substrate. 1 is a side view illustrating an example of the overall configuration of an image forming apparatus according to an exemplary embodiment. FIG. 2 is a plan view showing a main configuration of the image forming apparatus.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 2 is an exploded perspective view showing a main configuration of a droplet discharge head as a liquid discharge apparatus according to the present embodiment.
FIG. 1 is a partial cross-sectional view of the actuator substrate that constitutes the droplet discharge head in the present embodiment, taken along the line AA ′ in FIG.
As shown in FIG. 2, the droplet discharge head according to this embodiment is formed by joining a subframe substrate 100, an actuator substrate 200, and a nozzle substrate 300 with an adhesive or the like.

  The subframe substrate 100 is provided with a protective cavity 191 that forms a protective space for protecting the piezoelectric element and a subframe bonding surface 192 on the actuator substrate 200 side. Although not shown, the subframe substrate 100 includes a liquid supply hole for supplying a liquid such as ink from the outside, an opening for routing the signal wiring to the outside, an alignment mark with the actuator substrate 200, and the like. Is formed.

The actuator substrate 200 has a piezoelectric element 201 that is an actuator element as an electromechanical conversion element formed on one surface (upper surface in the drawing). The piezoelectric element 201 has a configuration in which a lower electrode layer 208 as a lower electrode, a piezoelectric layer 209 made of PZT (lead zirconate titanate), and an upper electrode layer 210 as an upper electrode are laminated. The lower electrode layer 208 is formed of three layers of a TiO ₂ film (not shown), a Pt film 208b, and an SRO (strontium ruthenate, SrRuO ₃ ) film 208c. The piezoelectric layer 209 is formed into a thin film by a sol-gel method. The upper electrode layer 210 is formed of an SRO film 210a and a Pt film 210b.

A protective film 204 for the piezoelectric element 201 is formed on the upper electrode layer 210. As will be described in detail later, the protective film 204 of the present embodiment includes an alumina layer (Al ₂ O ₃ layer) 204a as a moisture resistant layer and a polysilicon layer (polycrystalline silicon layer) 204b as a moisture resistant protective layer. It has a multi-layer structure. On this protective film 204, a silicon oxide insulating film 213 made of a silicon oxide film is formed as an insulating film for insulating between the lead-out wiring 205 and the piezoelectric element 201. However, in the region where the piezoelectric element 201 is deformed / displaced, the silicon oxide insulating film 213 is removed as an unnecessary portion.

  In addition, a lead-out wiring 205 made of a conductive material for transmitting a drive signal from the external drive circuit is in contact with the upper electrode layer 210 through a contact hole 211 as a connection through hole. Further, a passivation protective film 206 for protecting the lead wiring 205 is also formed.

  A pressurized liquid chamber 202 and a partition wall 207 are formed on the other surface (lower surface in the drawing) side of the actuator substrate 200 via a vibration plate 203.

  In the nozzle substrate 300, nozzles 301 as droplet discharge holes formed by press working or Ni electroforming method are arranged and bonded to the surface of the actuator substrate 200 on the pressurized liquid chamber side by an adhesive or the like. ing.

  In the droplet discharge head configured as described above, a drive signal (electric signal) input from an external drive circuit (not shown) is transmitted from the lead-out wiring 205 to the piezoelectric element 201 through the contact hole 211 and applied. The piezoelectric element 201 is deformed by this drive signal, thereby causing displacement on the surface of the diaphragm 203 and generating pressure in the liquid in the pressurized liquid chamber 202. A desired droplet can be ejected from the nozzle 301 by the pressure generated in the liquid in the pressurized liquid chamber 202.

Next, an example of a method for producing the actuator substrate 200 constituting the droplet discharge head of the present embodiment will be described with reference to FIGS.
First, as shown in FIGS. 3 and 4, the vibration plate 203 is formed on the silicon substrate 200 ′ serving as the base of the actuator substrate 200. The diaphragm 203 is a laminate of a thermal oxide film, a polysilicon film (polycrystalline silicon) by LPCVD (Low Pressure Chemical Vapor Deposition), a silicon nitride film, and a silicon oxide film, and has a thickness of 2.2 [ μm].

Next, as shown in FIG. 5, as the lower electrode layer 208, a TiO ₂ film 208a, a Pt film 208b, and an SRO film 208c are sequentially stacked on the diaphragm 203 by a sputtering method. Next, the piezoelectric layer 209 is formed by repeating spin coating by sol-gel method and thermal baking. Further, as the upper electrode layer 210, an SRO film 210a and a Pt film 210b are sequentially formed.

  Next, as shown in FIG. 6, the upper electrode layer 210, the piezoelectric layer 209, and the lower electrode layer 208 formed by lamination are formed into a desired pattern by a photolithography method and an etching method using a resist pattern 212. To do. In this embodiment, the piezoelectric elements 201 are formed at a pitch of about 85 [μm] in order to create a 300 dpi droplet discharge head.

  Next, as shown in FIG. 7, a protective film 204 is formed on the desired patterned piezoelectric element 201. The protective film 204 in the present embodiment has a two-layer structure in which an alumina layer 204a as a moisture resistant layer and a polysilicon layer 204b as a moisture resistant protective layer are laminated, but has another function. Layers may be added. In the present embodiment, the alumina layer 204a has a thickness of 50 [nm] and the polysilicon layer 204b has a thickness of 50 [nm], but these thicknesses are appropriately set. However, if the layer thicknesses of these layers 204a and 204b are too thick, the displacement of the piezoelectric element 201 is hindered and an appropriate displacement characteristic cannot be obtained. It is not possible to secure sufficient roles and functions. Therefore, it is desirable to determine the layer thickness of the alumina layer 204a and the polysilicon layer 204b in consideration of these.

The alumina layer 204a is a protective layer for preventing the displacement characteristics from deteriorating when the piezoelectric element 201 is exposed to moisture in the air. If the layer is excellent in water resistance and permeation resistance, Al ₂ O _{3 is used.} The layer is not limited to this, and may be a layer made of another material.

  The polysilicon layer 204b protects the alumina layer 204a from being damaged during the process of removing unnecessary portions of the silicon oxide insulating film 213 that insulates between the lead-out wiring 205 and the piezoelectric element 201 from the protective film 204. It is a protective layer. In this embodiment, as will be described later, since the unnecessary portion of the silicon oxide insulating film 213 is removed by dry etching, the polysilicon layer 204b functions as a stop layer in the dry etching process. Therefore, a material having a high etching selectivity with respect to the silicon oxide insulating film 213 is suitable for the moisture resistant protective layer. In the present embodiment, the polysilicon layer 204b is used as the moisture resistant protective layer, but other materials such as an amorphous silicon layer can also be used.

  By providing such a polysilicon layer 204b, it is possible to suppress the occurrence of damage such as the occurrence of pinhole defects in the alumina layer 204a due to process damage (discharge damage) during the dry etching process.

  When the protective film 204 is formed on the piezoelectric element 201 as described above, the silicon oxide insulating film 213 is formed on the protective film 204. This silicon oxide insulating film 213 is an insulating film for ensuring insulation between the electrode layer of the piezoelectric element 201 and the lead-out wiring 205, and in this embodiment, a silicon oxide film having a thickness of 1.0 [μm]. However, an insulating film made of another material may be used.

  Next, as shown in FIGS. 8 and 9, a contact hole 211 is formed as a connection through hole for contacting the upper electrode layer 210 and the lower electrode layer 208 with the lead-out wiring 205. In FIG. 9, contact holes for the lower electrode layer 208 are not shown.

  Next, as shown in FIGS. 10 and 11, a lead-out wiring 205 having a predetermined pattern is formed using the resist pattern 212. The lead wiring 205 is formed of, for example, an Al film having a thickness of 4 [μm]. A part of the lead-out wiring 205 is joined to the subframe joining surface 192 of the subframe substrate 100 together with the electrical connection with the piezoelectric element 201 to form a partition wall.

  Next, as shown in FIGS. 12 and 13, a passivation protection film 206 is formed on the lead-out wiring 205 using the resist pattern 212. As the passivation protection film 206, a silicon nitride film is formed by a CVD method. The thickness of the passivation protective film 206 is set to 800 [nm], for example.

  Further, the passivation protection film 206 and the silicon oxide insulating film 213 on the piezoelectric element 201 are removed by a photolithography method and a dry etching method in order to inhibit the displacement of the piezoelectric element 201. At this time, the surface of the protective film 204 of the piezoelectric element 201 is exposed by etching the silicon oxide insulating film 213 by dry etching. At this time, when the protective film 204 is composed of only a moisture resistant layer (alumina layer 204a) as in the prior art, the moisture resistant layer is subject to process damage due to the dry etching process. For example, pinhole defects may occur in the moisture-resistant layer due to discharge generated during the dry etching process. Therefore, there is a possibility that the function of the moisture-resistant layer that prevents the displacement characteristics from deteriorating when the piezoelectric element comes into contact with moisture in the air cannot be obtained appropriately.

  In the present embodiment, the protective film 204 of the piezoelectric element 201 has a two-layer configuration in which a polysilicon layer 204b as a moisture resistant layer protective layer is provided on an alumina layer 204a that is a moisture resistant layer. Therefore, the process damage that the alumina layer 204a receives during the dry etching process is reduced, and the function of the alumina layer 204a as the moisture resistant layer is not hindered.

  Next, as shown in FIG. 14, in order to form a pressurized liquid chamber 202 on the opposite surface of the piezoelectric element 201, an unnecessary substrate portion 200 '' in the drawing is polished by polishing to remove the substrate 200 ′. Process to desired thickness. In the illustrated example, the substrate 200 ′ having a thickness of 75 [μm] is left as the height of the pressurized liquid chamber 202.

Next, as shown in FIGS. 15 and 16, a resist pattern 212 for forming the pressurizing liquid chamber 202 is formed, and the pressurizing liquid chamber 202 is formed by dry etching.
Through the above steps, the actuator substrate 200 is formed as shown in FIG.

  Note that the liquid droplet ejection head according to the present embodiment requires a liquid supply hole for introducing liquid from the outside, and the description thereof is omitted.

Next, an example of an image forming apparatus including the droplet discharge head according to the present embodiment will be described.
FIG. 18 is a side view showing an example of the overall configuration of the image forming apparatus according to the present embodiment. FIG. 19 is a plan view showing the main configuration of the image forming apparatus.
In the image forming apparatus of this embodiment, a carriage 103 is slidably held in a main scanning direction by a guide rod 101 and a guide rail 102 which are guide members horizontally mounted on left and right side plates (not shown). The carriage 103 is moved and scanned in the direction indicated by the arrow (main scanning direction) via the timing belt 105 by the main scanning motor 104.

  For example, four droplet ejection heads 107 that eject droplets for image formation of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) are mounted on the carriage 103. Yes. The droplet discharge head 107 is mounted such that a plurality of nozzles as droplet discharge ports are arranged in a direction crossing the main scanning direction and the droplet discharge direction is directed downward. As the droplet discharge head 107, one using an actuator element such as the aforementioned piezoelectric element is used.

  The carriage 103 is equipped with a sub-tank 108 for each color for supplying each color liquid to the droplet discharge head 107. The sub tank 108 is replenished and supplied with liquid from a main tank (liquid cartridge) via a liquid supply tube (not shown). Note that the liquid cartridge may be mounted without using the sub tank.

  In addition, the image forming apparatus according to the present exemplary embodiment includes a paper feeding unit for feeding paper 112 as a recording medium stacked on a paper stacking unit (pressure plate) 111 such as a paper feeding cassette 110. The paper feed unit includes a half-moon roller (paper feed roller) 113 that separates and feeds paper 112 from the paper stacking unit 111 one by one, and a separation pad 114 that is opposed to the paper feed roller 113 and made of a material having a large friction coefficient. ing. The separation pad 114 is urged toward the paper feed roller 113 side.

  In addition, a transport unit for transporting the paper 112 fed from the paper feed unit below the droplet discharge head 107 is provided. The transport unit includes a transport belt 121 for electrostatically attracting and transporting the paper 112 and a counter roller for transporting the paper 112 fed from the paper feed unit via the guide 115 with the transport belt 121 interposed therebetween. 122. Further, the transport unit is biased toward the transport belt 121 by a transport guide 123 for changing the direction of the sheet 112 sent substantially vertically upward by approximately 90 ° and following the transport belt 121 and the pressing member 124. A tip pressurizing roller 125. Further, the transport unit includes a charging roller 126 that is a charging unit for charging the surface of the transport belt 121.

  The conveyor belt 121 is an endless belt and is stretched between the conveyor roller 127 and the tension roller 128. Further, the conveyance belt 121 is configured to circulate in the belt conveyance direction (sub-scanning direction) in FIG. 19 by rotating the conveyance roller 127 from the sub-scanning motor 131 via the timing belt 132 and the timing roller 133. ing. Note that a guide member 129 is disposed on the back side of the transport belt 121 corresponding to the image forming area formed by the droplet discharge head 107.

  As shown in FIG. 19, a slit disk 134 is attached to the shaft of the transport roller 127. Further, a sensor 135 for detecting the slit of the slit disk 134 is provided. These slit disk 134 and sensor 135 constitute an encoder 136.

  The charging roller 126 is disposed so as to contact the surface layer of the conveyor belt 121 and rotate following the rotation of the conveyor belt 121, and applies 2.5 [N] to both ends of the shaft as a pressing force.

  Further, an encoder scale 142 having slits is provided on the front side of the carriage 103 as shown in FIG. On the front surface side of the carriage 103, an encoder sensor 143 including a transmission type photosensor that detects a slit of the encoder scale 142 is provided. These components constitute an encoder 144 for detecting the position of the carriage 103 in the main scanning direction (position relative to the home position).

  Further, the image forming apparatus according to the present embodiment includes a paper discharge unit for discharging the paper 112 on which an image is formed by the droplet discharge head 107. The paper discharge unit includes a separation unit for separating the paper 112 from the transport belt 121, a paper discharge roller 152 and a paper discharge roller 153, and a paper discharge tray 154 that stocks the paper 112 to be discharged.

  A double-sided paper feeding unit 161 is detachably attached to the back of the image forming apparatus. The double-sided paper feeding unit 161 takes in the paper 112 returned by the reverse rotation of the transport belt 121, reverses it, and feeds it again between the counter roller 122 and the transport belt 121.

  In the image forming apparatus having the above configuration, the sheets 112 are separated and fed one by one from the sheet feeding unit, and the sheet 112 fed substantially vertically upward is guided by the guide 115, and the conveyance belt 121 and the counter roller 122 It is sandwiched and conveyed. Further, the leading end of the paper 112 is guided by the transport guide 123 and pressed against the transport belt 121 by the front end pressure roller 125, and the transport direction is changed by approximately 90 °.

  At this time, a positive voltage and a negative output are alternately applied to the charging roller 126 from a high voltage power source by a control circuit (not shown), that is, an alternating voltage is applied. As a result, the charging voltage pattern in which the conveyor belt 121 alternates, that is, plus and minus are alternately charged in a band shape with a predetermined width in the sub-scanning direction that is the circumferential direction. When the paper 112 is fed onto the conveyance belt 121 charged alternately with plus and minus, the paper 112 is attracted to the conveyance belt 121 by electrostatic force, and the paper 112 is conveyed in the sub-scanning direction by the circular movement of the conveyance belt 121. Is done.

  Therefore, the droplet discharge head 107 is driven according to the image signal while moving the carriage 103. Thereby, droplets are ejected onto the stopped paper 112 to form an image for one line, and after the paper 112 is conveyed by a predetermined amount, an image for the next line is formed. Upon receiving a recording end signal or a signal that the rear end of the paper 112 has reached the image forming area, the image forming operation is finished, and the paper 112 is discharged onto the paper discharge tray 154.

  In the case of duplex printing, when the image formation on the front surface (the surface on which an image is first formed) is completed, the conveyance belt 121 is reversely rotated. As a result, the image-formed paper 112 is fed into the double-sided paper feeding unit 161, and the paper 112 is reversed (with the back surface being the image-forming surface) and fed again between the counter roller 122 and the conveying belt 121. Make paper. Then, timing control is performed, and the sheet is conveyed onto the conveyance belt 121 in the same manner as described above to form an image on the back surface, and then discharged onto the discharge tray 154.

  Note that the image forming apparatus according to the present invention can also be applied to a printer, a facsimile machine, a copying machine, a multi-function machine thereof, and the like. The present invention also relates to a droplet discharge head that discharges a liquid other than an image-forming liquid (ink), such as a DNA sample, a resist, or a pattern material, and a droplet discharge device that includes the droplet discharge head. Can also be applied.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A nozzle plate such as a nozzle substrate 300 having nozzle holes such as a nozzle 301 for discharging a liquid such as ink, a pressurized liquid chamber 202 communicating with the nozzle holes, and a vibration plate constituting a part of the pressurized liquid chamber 203, a piezoelectric element 201 that is covered with a protective film 204, applies vibration to the diaphragm and generates a pressure change in the pressurized liquid chamber, and a drive signal from an external drive circuit at a predetermined position of the piezoelectric element. In a liquid discharge apparatus such as a droplet discharge head provided with a signal wiring such as a lead-out wiring 205 for transmission, the protective film 204 covering the piezoelectric element includes a moisture resistant layer such as an alumina layer 204a and a layer higher than the moisture resistant layer. And a dry etching process for removing unnecessary portions of the insulating film such as a silicon oxide insulating film 213 that is formed on the protective film and insulates between the signal wiring and a portion other than the predetermined portion of the piezoelectric element. Characterized in that it comprises resistant stratification during the process, such as a ring is a moisture layer for the protective layer of the polysilicon layer 204b or the like to protect from being damaged.
According to this, the moisture-resistant layer protective layer prevents the moisture-resistant layer of the piezoelectric element from being damaged during the process of removing unnecessary portions of the insulating film from the protective film. Therefore, the function of the moisture-resistant layer that prevents the piezoelectric element from coming into contact with moisture in the air is less likely to be impaired, and the displacement characteristic of the piezoelectric element is hardly deteriorated.

(Aspect B)
In the aspect A, the moisture resistant layer protective layer protects the moisture resistant layer from being damaged by a discharge generated in a dry etching process for removing unnecessary portions of the insulating film.
According to this, even when the unnecessary portion of the insulating film is removed by the dry etching process, it is possible to suppress the moisture-resistant layer from being damaged by the discharge generated during the dry etching process.

(Aspect C)
In the aspect B, the moisture-resistant layer protective layer is a conductive layer.
According to this, it is possible to stably protect the moisture resistant layer from electric discharge generated during the dry etching process.

(Aspect D)
In the aspect B or C, the moisture-resistant layer protective layer is a polycrystalline silicon layer or an amorphous silicon layer.
According to this, it is possible to easily and stably protect the moisture resistant layer from electric discharge generated during the dry etching process.

(Aspect E)
In any one of the aspects A to D, the thickness of the moisture resistant layer is 40 [nm] or more and 70 [nm] or less, and the thickness of the moisture resistant layer protective layer is 20 [nm] or more and 100 [nm] or less. It is characterized by being.
According to this, it is easy to ensure the functions of the moisture-resistant layer and the moisture-resistant layer protective layer as long as the displacement characteristics of the piezoelectric element 201 are not impaired.

(Aspect F)
In any one of the aspects A to E, the moisture-resistant layer is an oxide layer.
This is advantageous for the insulation resistance of the piezoelectric element.

In an image forming apparatus that forms an image on a recording material by ejecting liquid onto the recording material from the liquid ejecting apparatus, the liquid ejecting apparatus according to any one of the aspects A to F is used as the liquid ejecting apparatus. It is characterized by that.
According to this, since the displacement characteristics of the piezoelectric element are not easily deteriorated, the liquid ejection characteristics can be stably maintained.

A nozzle plate having a nozzle hole for discharging liquid, a pressurized liquid chamber communicating with the nozzle hole, a vibrating plate constituting a part of the pressurized liquid chamber, and a protective film, and vibrating on the vibrating plate In a method for manufacturing a liquid ejection device, comprising: a piezoelectric element that generates a pressure change in the pressurized liquid chamber, and a signal wiring that transmits a drive signal from an external drive circuit to a predetermined location of the piezoelectric element. A protective film forming step for forming a protective film including a moisture resistant layer on the piezoelectric element, and an insulating film for insulating between the signal wiring and a portion other than the predetermined portion of the piezoelectric element are formed on the protective film. An insulating film forming step, a signal wiring forming step for forming the signal wiring for the piezoelectric element on which the insulating film is formed, and an insulating film removal for removing unnecessary portions of the insulating film after forming the signal wiring And forming the protective film Degree, the moisture layer protective layer for protecting the the moisture layer is damaged during the insulation film removing step, thereby forming in an upper layer than resistant Shimeso.
According to this, the moisture resistant layer of the piezoelectric element is prevented from being damaged by the protective layer for the moisture resistant layer during the insulating film removing step. Therefore, the function of the moisture-resistant layer that prevents the piezoelectric element from coming into contact with moisture in the air is less likely to be impaired, and the displacement characteristic of the piezoelectric element is hardly deteriorated.

100 Subframe substrate 103 Carriage 107 Droplet ejection head 200 Actuator substrate 201 Piezoelectric element 202 Pressurizing fluid chamber 203 Vibration plate 204 Protective film 204a Alumina layer 204b Polysilicon layer 205 Lead-out wiring 206 Passivation protective film 208 Lower electrode layer 209 Piezoelectric layer 210 Upper electrode layer 211 Contact hole 212 Resist pattern 213 Silicon oxide insulating film 300 Nozzle substrate 301 Nozzle

Japanese Patent Application Laid-Open No. 11-077999

Claims (8)

A nozzle plate having nozzle holes for discharging liquid;
A pressurized liquid chamber communicating with the nozzle hole;
A diaphragm constituting a part of the pressurized liquid chamber;
A piezoelectric element that is covered with a protective film, applies vibration to the diaphragm, and generates a pressure change in the pressurized liquid chamber;
In a liquid ejection apparatus provided on a protective film of the piezoelectric element and including a signal wiring that transmits a drive signal from an external drive circuit to a predetermined portion of the piezoelectric element,
The protective film that covers the piezoelectric element is formed of a moisture-resistant layer and an insulating film that is formed above the moisture-resistant layer and that insulates between the signal wiring and a portion other than the predetermined portion of the piezoelectric element. A liquid ejection apparatus comprising: a protective layer for a moisture resistant layer that protects the moisture resistant layer from being damaged during the step of removing the portion from the protective film. The liquid ejection apparatus according to claim 1,
The liquid ejection apparatus according to claim 1, wherein the protective layer for the moisture resistant layer protects the moisture resistant layer from being damaged by a discharge generated in a dry etching process for removing an unnecessary portion of the insulating film. The liquid ejection apparatus according to claim 2, wherein
The liquid ejection apparatus, wherein the moisture resistant protective layer is a conductive layer. The liquid ejection device according to claim 2 or 3,
The liquid ejection apparatus, wherein the moisture-resistant protective layer is a polycrystalline silicon layer or an amorphous silicon layer. The liquid ejection apparatus according to any one of claims 1 to 4,
The moisture-resistant layer has a thickness of 40 [nm] or more and 70 [nm] or less,
The liquid ejection apparatus according to claim 1, wherein the moisture resistant protective layer has a thickness of 20 nm to 100 nm. The liquid ejection apparatus according to any one of claims 1 to 5,
The liquid ejection apparatus, wherein the moisture resistant layer is an oxide layer. In an image forming apparatus for forming an image on a recording material by discharging liquid from the liquid discharging device to the recording material,
An image forming apparatus using the liquid discharge apparatus according to claim 1 as the liquid discharge apparatus. A nozzle plate having a nozzle hole for discharging liquid, a pressurized liquid chamber communicating with the nozzle hole, a diaphragm constituting a part of the pressurized liquid chamber, and applying vibration to the diaphragm to add the pressure In a method for manufacturing a liquid ejection apparatus, comprising: a piezoelectric element that generates a pressure change in a pressure fluid chamber; and a signal wiring that transmits a drive signal from an external drive circuit to a predetermined location of the piezoelectric element.
A protective film forming step of forming a protective film including a moisture resistant layer on the piezoelectric element;
An insulating film forming step of forming an insulating film on the protective film for insulating between the signal wiring and a portion other than the predetermined portion of the piezoelectric element;
A signal wiring forming step of forming the signal wiring with respect to the piezoelectric element on which the insulating film is formed;
An insulating film removing step of removing an unnecessary portion of the insulating film after forming the signal wiring,
In the protective film forming step, a protective layer for a moisture resistant layer that protects the moisture resistant layer from being damaged during the insulating film removing step is formed in a layer above the moisture resistant layer. Method.