JP2008087469A - Liquid discharge head and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent short circuit generated between upper and lower electrodes and prevent damage to a piezoelectric film. <P>SOLUTION: In a piezoelectric thin film 107, the region corresponding to the part between a plurality of individual liquid chambers 102 has a film thickness smaller than that of the regions corresponding to the individual liquid chambers 102 and covers the entire lower electrode 106 which is provided at least in the region corresponding to the part between the plurality of individual liquid chambers 102. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid discharge head that includes a liquid chamber that communicates with a discharge port that discharges liquid as droplets and uses a piezoelectric body provided corresponding to the liquid chamber, and a method for manufacturing the liquid discharge head.

  The ink jet recording apparatus has advantages that it can be easily colored, has high recording quality, and can perform high speed recording. Furthermore, the ink jet recording apparatus can be recorded on plain paper and the like, and has many excellent advantages such as easy miniaturization of the apparatus, so that it is used as an image recording apparatus such as a printer or a facsimile. .

  One example of an ink jet recording apparatus uses an ink jet head having an orifice plate for discharging a liquid. The orifice plate penetrates the second surface of the flow path substrate from the individual liquid chamber provided on the first surface of the flow path substrate, the individual liquid chamber provided on the first surface of the flow path substrate. A through path and a discharge port bonded to the second surface of the flow path substrate and communicating with the through path are provided.

  In order to discharge ink droplets, it is necessary to pressurize the individual liquid chambers. As the pressure generating means, there is a bubble type device in which a liquid is foamed by a heating element installed in an individual liquid chamber to discharge a droplet. Other pressure generating means include a piezo type that forms droplets by deforming a diaphragm that forms a part of an individual liquid chamber with a piezoelectric element, and deforms the diaphragm by electrostatic force. In general, an electrostatic type that discharges droplets is used.

  In such an ink jet head, with the recent demand for higher definition of image formation, high integration is achieved by arranging a large number of pressure generating sources such as individual liquid chambers of a flow path substrate and piezoelectric elements. Yes.

  In order to meet these demands, in the above-described piezo-type inkjet head, for example, electrodes and piezoelectric bodies are formed on the entire surface of the diaphragm by a film formation technique, and electrodes and piezoelectric bodies corresponding to individual liquid chambers are formed using a photolithography technique. The one which processes is proposed. A high-density ink jet head is realized by using a film forming technique and a photolithography technique. Further, by using a Si substrate or a metal member for the flow path substrate or the orifice plate, the flow path or the discharge port can be formed with high accuracy.

Generally, the piezoelectric body is provided at a position corresponding to each individual liquid chamber, and is processed to have a width narrower than the width of the individual liquid chamber. The piezoelectric material in the region not corresponding to the individual liquid chamber is completely removed by the film thickness. Also, in recent years, dry etching technology using chlorine-based gas or the like has been introduced for processing these piezoelectric bodies. Compared with the wet etching method using hydrofluoric acid or an acid-based solution, the dry etching method can easily control the etching rate and the etching shape, and enables high-precision processing. Patent Document 1 discloses a technique for processing a layer structure of a piezoelectric element having a Pt electrode by dry etching.
JP 2000-357826 A

  However, when the piezoelectric body is processed by the dry etching method, in the case where the lower electrode is not patterned as in Patent Document 1, the lower electrode functions as an etching stop layer that stops the progress of etching. When the piezoelectric body is processed with such a configuration, the lower electrode is slightly etched, although the displacement performance and mechanical characteristics of the piezoelectric body are hardly affected. In particular, when a Pt electrode is used as the lower electrode, the surface of the Pt electrode is struck with chlorine gas used for processing the piezoelectric body, and the component of the Pt electrode may adhere to the end face of the processed piezoelectric body. is there. Thus, when metal adheres to the end face of the piezoelectric body, there is a problem that causes a short circuit between the upper and lower electrodes and a breakdown of the piezoelectric thin film.

  In addition, if the lower electrode in the vicinity of the piezoelectric thin film serving as the drive unit is exposed, there is a problem that causes a short circuit between the upper and lower electrodes during driving or causes the electrode or the piezoelectric thin film to be destroyed. is there.

  Therefore, an object of the present invention is to provide a liquid discharge head that can prevent a short circuit between upper and lower electrodes and prevent damage to a piezoelectric film, and a method for manufacturing the liquid discharge head.

  In order to achieve the above-mentioned object, a liquid discharge head according to the present invention is provided corresponding to each of a plurality of liquid chambers for communicating with a discharge port for discharging a liquid and pressurizing the liquid, and for each of the plurality of liquid chambers. A plurality of piezoelectric elements having a lower electrode, a piezoelectric film, and an upper electrode stacked in order from the liquid chamber side, and extending to the region corresponding to the plurality of liquid chambers. The piezoelectric film is configured such that a region corresponding to the plurality of liquid chambers has a smaller film thickness than a region corresponding to the liquid chamber, and at least the plurality of liquid chambers. All of the lower electrodes provided in the corresponding regions between them are covered.

  Further, the method for manufacturing a liquid discharge head according to the present invention includes a plurality of liquid chambers for pressurizing the liquid in communication with the discharge ports for discharging the liquid, and corresponding to each of the plurality of liquid chambers, A plurality of piezoelectric elements having a lower electrode, a piezoelectric film, and an upper electrode stacked in order from the liquid chamber side, and the lower electrode is provided to a corresponding region between the plurality of liquid chambers. A method of manufacturing a liquid discharge head in which the piezoelectric film covers all of the lower electrode provided at least in the region, the step of forming a material film of the piezoelectric film on the lower electrode, and the piezoelectric The plurality of liquids of the material film of the piezoelectric film so that a region corresponding to the space between the plurality of liquid chambers of the body film is smaller than a region corresponding to the liquid chamber. Etching a corresponding region between the chambers. To.

  As described above, according to the present invention, when a part of the piezoelectric film exists on the lower electrode, the lower electrode is etched by the etching process, and the component of the lower electrode adheres to the end face of the piezoelectric film. Can be prevented. Further, according to the present invention, since the lower electrode is covered with a part of the piezoelectric film, a short circuit between the upper and lower electrodes and the destruction of the piezoelectric film can be prevented.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  The liquid discharge head according to the present invention is applied to, for example, an ink jet recording head that prints on paper, cloth, leather, nonwoven fabric, an OHP sheet, or a patterning device or a coating device that attaches liquid to a solid material such as a substrate or a plate. Is possible. A typical ink jet recording head will be described below.

(First embodiment)
As shown in FIG. 1, the ink jet head of this embodiment includes an orifice plate 111 having an ejection port for ejecting ink, and a Si substrate 101 bonded to the orifice plate 111. The Si substrate 101 has a plurality of individual liquid chambers 102 that communicate with the ejection ports and pressurize ink, and a partition wall 109 that separates the individual liquid chambers 102.

  The ink jet head also includes a diaphragm 105 formed on the individual liquid chamber 102 and a piezoelectric element as pressure generating means for displacing the diaphragm 105. The piezoelectric element is provided on the diaphragm 105. The lower electrode 106 and the piezoelectric film (hereinafter also referred to as “piezoelectric thin film” for convenience) stacked on the diaphragm 105 in order. 107), and the upper electrode 108 is formed.

  The piezoelectric thin film 107 has a region corresponding to the center of the individual liquid chamber 102 and a region corresponding to the partition 109, and the film thickness of the region corresponding to the partition 109 corresponds to the center of the individual liquid chamber 102. It is smaller than the film thickness of the region to be processed. In other words, the film thickness of the piezoelectric thin film 107 is smaller in the region corresponding to the space between the plurality of individual liquid chambers 102 (between the liquid chambers) than in the region corresponding to the individual liquid chambers 102. In addition, the piezoelectric thin film 107 covers all the lower electrodes 108 provided in a corresponding region between at least the plurality of individual liquid chambers 102.

  The ink jet head of the present embodiment causes the ink in the individual liquid chamber 102 to fly from the ejection port with high accuracy by integrally deforming the diaphragm 105 by deformation of the piezoelectric thin film 107.

  A method of manufacturing the ink jet head configured as described above will be described.

  As shown in FIG. 2, a flow path such as the individual liquid chamber 102 is formed using a Si substrate 101 having a thickness of 200 μm. Using an oxide film having a thickness of 1 μm as an etching mask, an ICP (Inductively Coupled Plasma) etching apparatus known as a Si deep-drilling technique is used.

  First, after forming an etching mask for the individual liquid chamber 102 on the surface of the Si substrate 101, an individual liquid chamber 102 having a depth of 100 μm is formed by ICP etching. The length of the individual liquid chamber 102 in the longitudinal direction is 3 mm.

  Next, pattern etching masks for the nozzle communication port 103 and the common liquid chamber 104 are respectively formed on the back surface of the Si substrate 101, and the nozzle communication port 103 and the common liquid chamber 104 having a depth of 100 μm are formed using an ICP etching apparatus. Form each one.

  After processing the Si substrate 101, a vibration plate 105 is formed on the surface of the Si substrate 101 so as to cover the individual liquid chamber 102. In this embodiment, SD2 glass (HOYA: registered trademark) is anodically bonded as the diaphragm 105, and then the diaphragm 105 having a thickness of about 5 μm is formed by polishing or wet etching.

  Next, after forming a Pt film having a thickness of 300 nm as the lower electrode 106 on the vibration plate 105 by a film forming method, a material film forming the piezoelectric thin film 107 is formed. As the piezoelectric thin film 107, a Pb (Zr, Ti) O3 perovskite oxide (hereinafter referred to as PZT) film made of lead, titanium, and zirconium is formed to a thickness of about 3 μm by sputtering. After the Si substrate 101 on which the piezoelectric thin film 107 is formed is taken out from the sputtering apparatus, baking is performed at 700 ° C. in an oxygen atmosphere to crystallize the PZT film. At this time, the composition of the PZT film is set to Pb (Zr; 0.52, Ti; 0.48) O3 so as to obtain good piezoelectricity. The composition of the PZT film is not necessarily limited to the above-described composition, and other compositions may be used. Further, the thickness of the PZT film is not limited to 3 μm.

  Next, a Pt film is formed on the piezoelectric thin film 107 as a Pt electrode having a thickness of 300 nm to be the upper electrode 108. Thereafter, the piezoelectric thin film 107 and the upper electrode 108 are processed by etching so as to correspond to the individual liquid chambers 102. The details will be described with reference to FIG. 3 showing the individual liquid chamber 102 from the cross-sectional direction.

  First, a photoresist is applied and patterned on the upper electrode 108, and a Pt film in a region not corresponding to the individual liquid chamber 102 is removed by dry etching with a gas such as BCl 3 (FIG. 3A). In addition to dry etching using BCl 3, the upper electrode 108 may be processed by Ar ion milling. In the present embodiment, the length of the upper electrode 108 in the longitudinal direction is 3 mm, but it is not always necessary to have this size.

  Next, patterning is performed again with a resist width slightly larger than the width of the upper electrode 108 so as to cover the upper electrode 108, and a part of the piezoelectric thin film 107 is removed by etching using a chlorine-based gas (FIG. 3 ( b)). In this embodiment, dry etching is performed using a mixed gas of Cl 2 and CF 4. The etching rate of the PZT film which is the piezoelectric thin film 107 is relatively stable, and the etching amount of the piezoelectric thin film 107 can be controlled by managing the etching time. In the present embodiment, the etching is performed so that the piezoelectric thin film 107 at least in a region corresponding to the partition wall 109 has a thickness of about 0.5 μm. Further, in order to further reduce the difference in etching rate due to the difference in pattern shape in the in-plane direction of the piezoelectric thin film 107, an extra dummy resist pattern is provided beside the elements at both ends used for actual driving. May be.

  The piezoelectric thin film 107 is not entirely removed in the film thickness direction by etching, and the piezoelectric thin film 107b having a thickness of about 0.5 μm remains on the lower electrode 106. That is, in this embodiment, the lower electrode 106 is not exposed and the lower electrode 106 is not etched. Therefore, according to the present embodiment, components such as the lower electrode 106 do not adhere to the end face of the piezoelectric thin film 107a, and leakage and destruction can be prevented. Furthermore, the lower electrode 106 in the vicinity of the individual liquid chamber 102 is covered with the piezoelectric thin film 107b, so that the occurrence of leakage between the upper electrode 108 and the lower electrode 106 and the destruction of the piezoelectric element are greatly suppressed. Can do.

  Of the piezoelectric thin film 107, the region of the piezoelectric thin film 107a having a thickness of 3 μm that remains without being etched is considered to be a region that actually contributes to driving. The piezoelectric thin film 107b having a thickness of about 0.5 μm exists above the partition wall 109, which is considered to be a factor that hinders the displacement of the piezoelectric thin film 107 as a whole. However, in the case of the present embodiment, the amount of displacement changes only by about 5% compared to the configuration in which the piezoelectric thin film 107b corresponding to the upper part of the partition wall 109 does not exist, that is, when all the film thickness of 3 μm is removed by etching. There wasn't. Therefore, if the thickness of the piezoelectric thin film 107b corresponding to the upper portion of the partition wall 109 is about 0.5 μm, the displacement is hardly affected and a sufficient amount of displacement is obtained.

  Furthermore, investigations were repeated on the reduction of the displacement with respect to the film thickness of the piezoelectric thin film 107b above the partition wall 109. As a result, even if the film thickness of the piezoelectric thin film 107a is 3 μm and the film thickness of the piezoelectric thin film 107b is 1 μm, that is, the piezoelectric thin film 107 is removed by etching by a film thickness of 2 μm and only 1 μm is left. The amount decreased only about 15%. From the viewpoint of variation in etching speed in the surface of the piezoelectric thin film 107 and a reduction in displacement, the film thickness of the piezoelectric thin film 107b that remains without being removed by etching is preferably about 1 μm or less.

  In the case of the configuration of the present embodiment, the lower electrode 106 is taken out by etching and removing the piezoelectric thin film 107 by a thickness of 3 μm at a position away from the individual liquid chamber 102. The part is formed.

  Finally, on the back surface of the Si substrate 101, an orifice plate 111 formed by processing a Si wafer by ICP, or an orifice plate 111 formed by punching on a SUS plate or the like is bonded. Thereby, as shown in FIG. 1, an ink jet head using the piezoelectric thin film 107 is manufactured.

  As described above, according to the present embodiment, since a part of the piezoelectric thin film 107 exists on the lower electrode 106, a part of the lower electrode 106 is removed by etching, and the component of the lower electrode 106 is piezoelectric. Adhering to the end surface of the body thin film 107 can be prevented. Further, in the ink jet head of this embodiment, the lower electrode 106 is covered with a part of the piezoelectric thin film 107 which is an insulator, so that the short circuit between the upper and lower electrodes 108 and 106 and the destruction of the piezoelectric thin film 107 are prevented. Can be prevented.

  Further, according to the present embodiment, the piezoelectric thin film 107 can be processed into a desired shape with high accuracy by removing a part of the piezoelectric thin film 107 in the film thickness direction by dry etching.

  In this embodiment, Si is used for the constituent member of the individual liquid chamber 102 and the orifice plate 111, and glass is used as the material of the diaphragm 105. However, the present invention is not limited to this, and other materials and Also, other production methods may be used.

(Second Embodiment)
Next, an ink jet head according to a second embodiment will be described.

  As shown in FIG. 4, the ink jet head of this embodiment includes an orifice plate 211 having an ejection port for ejecting ink, and an SOI wafer 201 joined to the orifice plate 211. The SOI wafer 201 has a plurality of individual liquid chambers that communicate with the ejection ports and pressurize the ink, and a partition that separates the individual liquid chambers.

  The SOI wafer 201 is provided with a piezoelectric element as pressure generating means. This piezoelectric element is formed by a lower electrode 202, a piezoelectric thin film 203, and an upper electrode 204 that are sequentially stacked on an SOI wafer 201. In the present embodiment, the piezoelectric thin film 203 has a laminated piezoelectric thin film upper portion 203b and a piezoelectric thin film lower portion 203a.

  The piezoelectric thin film 203 has a region corresponding to the center of the individual liquid chamber and a region corresponding to the partition wall, and the film thickness of the piezoelectric thin film lower portion 203b located in the region corresponding to the partition wall is such that the individual liquid chamber has a film thickness. It is made smaller than the film thickness of the piezoelectric thin film upper part 203a located in the area | region corresponding to the center of this.

  A method of manufacturing the ink jet head configured as described above will be described.

  As shown in FIG. 5A, an adhesion layer of Ti having a thickness of 10 nm and a Pt film of 200 nm are formed as a lower electrode 202 on an SOI wafer 201 having a thickness of 200 μm. Subsequently, a piezoelectric thin film 203 is formed on the lower electrode 202. Therefore, the piezoelectric thin film 203 is formed of a two-layered material film in which the piezoelectric thin film lower portion 203a and the piezoelectric thin film upper portion 203b are stacked with different etching rates in the film thickness direction.

  In the step of forming the piezoelectric thin film lower portion 203a, first, as shown in FIG. 5B, a Pb (Zr, Ti) O3 perovskite oxide (hereinafter referred to as “Pb (Zr, Ti) O3” composed of lead, titanium, and zirconium is formed on the lower electrode 202. A film (referred to as PZT) is formed to a thickness of 0.2 μm by sputtering. After the SOI wafer 201 having the PZT film formed on the lower electrode 202 is taken out of the sputtering apparatus, it is baked at 700 ° C. in an oxygen atmosphere to form a crystallized polycrystalline PZT film. At this time, in order to obtain good piezoelectricity, the composition of the PZT film is set to Pb (Zr; 0.52, Ti; 0.48) O3. The composition of the PZT film is not necessarily limited to the above-described composition, and other compositions may be used. Thereafter, as shown in FIG. 5C, a PZT film is formed again by a sputtering method with a thickness of 2.8 μm, and this PZT film is used as the piezoelectric thin film upper portion 203b.

  Next, as shown in FIG. 5D, a Pt film having a thickness of 200 nm is formed as a Pt electrode to be the upper electrode 204 on the piezoelectric thin film upper portion 203b. Further, as the upper electrode 204, a Pt / Ti film may be formed. Ti serves as an adhesion layer between the Pt film and the piezoelectric thin film upper portion 203b.

  Thereafter, the upper electrode 204 and the piezoelectric thin film 203 are processed by etching. Details thereof will be described with reference to FIG.

  First, as shown in FIG. 6A, a photoresist is applied and patterned on the upper electrode 204, and the Pt portion is dry-etched with a gas such as BCl 3. In addition to dry etching using BCl 3, the upper electrode 204 may be processed by Ar ion milling.

  Next, as shown in FIG. 6B, the piezoelectric thin film upper portion 203b is etched with a chlorine-based gas. In this embodiment, etching is performed using the photomask used in the upper electrode 204 so that the width of the piezoelectric thin film upper portion 203b and the width of the upper electrode 204 are the same. Note that a photomask for etching the piezoelectric thin film upper portion 203b may be newly patterned with a resist so as to cover the upper electrode 204 and used as a photomask.

  The etching rate of the piezoelectric thin film upper portion 203b is relatively stable, and the etching amount can be adjusted by adjusting the etching time. Further, in the material film forming the piezoelectric thin film 203, the etching rate of the crystallized piezoelectric thin film lower part 203a is slower than the etching rate of the uncrystallized piezoelectric thin film upper part 203b. Therefore, the piezoelectric thin film lower portion 203a located on the individual liquid chamber 206 side (liquid chamber side) serves as an etching stop layer, and can accurately etch the piezoelectric thin film upper portion 203b.

  Subsequently, baking is performed again at 700 ° C. in an oxygen atmosphere, and the PZT film on the uncrystallized piezoelectric thin film 203b is crystallized to obtain a polycrystalline PZT film. In order to obtain good piezoelectricity, the composition of the PZT film is made to be Pb (Zr; 0.52, Ti; 0.48) O3. Note that the composition of the PZT film is not necessarily limited to the above-described composition, and other compositions may be used.

  The piezoelectric thin film 203 is not removed by etching all in the film thickness direction, and a piezoelectric thin film lower portion 203 a having a thickness of about 0.2 μm exists on the lower electrode 202. That is, in this embodiment, the lower electrode 202 is not exposed and the lower electrode 202 is not etched. Therefore, the component of the lower electrode 202 adheres to the end face of the piezoelectric thin film 203 during the etching of the piezoelectric thin film 203, and this does not cause a short circuit between the upper and lower electrodes 204 and 202. Further, since the lower electrode 202 in the vicinity of the individual liquid chamber 206 is covered with the piezoelectric thin film 203, it is possible to suppress the occurrence or breakage of leakage between the upper electrode 204 and the lower electrode 202. Further, since the adhesion area between the piezoelectric thin film 203 and the lower electrode 202 is wide, the piezoelectric thin film 203 is difficult to peel off.

  In this embodiment, an uncrystallized PZT film is used as the piezoelectric thin film upper portion 203b before processing, and a crystallized PZT film is used as the piezoelectric thin film lower portion 203a. However, this configuration is not necessarily required. For example, the piezoelectric thin film upper portion 203b is a polycrystalline PZT film, the piezoelectric thin film lower portion 203a is a single crystal PZT film, and vice versa, or both the piezoelectric thin film upper portion 203b and the piezoelectric thin film lower portion 203a are monocrystalline PZT. It may be a film. Furthermore, the piezoelectric thin film 203 is not limited to a PZT film, and may be barium titanate, zinc oxide, or the like.

  Thereafter, as shown in FIG. 6C, etching is performed from the back surface side of the SOI wafer 201 using the oxide film 205 of the SOI wafer 201 as an etching stop layer to form individual liquid chambers 206. For the etching, an ICP etching apparatus known as a Si deep trench technique is used. Note that the Si single crystal portion of the SOI wafer 201 functions as the vibration plate 207.

  Finally, an inkjet head using a piezoelectric thin film 203 is manufactured as shown in FIG. 4 by bonding an orifice plate 211 formed by processing a Si substrate by ICP to the back surface of the SOI wafer 201. .

  As described above, in the present embodiment, the piezoelectric thin film 203 is formed by stacking the piezoelectric thin film upper portion 203b and the piezoelectric thin film lower portion 203a having different etching rates in the film thickness direction. With this configuration, when the piezoelectric thin film 203 is etched, the progress of etching can be smoothly stopped without etching all of the film thickness direction.

  In the present embodiment, the piezoelectric thin film 203 is etched at a part of the piezoelectric thin film upper portion 203b using the piezoelectric thin film lower portion 203a as an etching stop layer. Accordingly, the piezoelectric thin film upper portion 203b can be etched with high accuracy by utilizing the fact that the etching rate of the piezoelectric thin film upper portion 203b and the piezoelectric thin film lower portion 203a are different.

  In the present embodiment, before the piezoelectric thin film 203 is etched, the piezoelectric thin film upper portion 203b is in an uncrystallized state and the piezoelectric thin film lower portion 203a is in a crystallized state. As a result, a portion where the etching rate in the film thickness direction of the piezoelectric thin film 203 is relatively high and a portion where the etching is relatively slow are easily formed.

  In addition, according to the present embodiment, the piezoelectric thin film 203 having desired piezoelectric characteristics can be formed by crystallizing the piezoelectric thin film upper portion 203b after the etching process of the piezoelectric thin film 203.

  In this embodiment, an SOI wafer is used as a member for forming the individual liquid chamber 206 and the vibration plate 207, and a Si substrate is used as the orifice plate 211. However, the present invention is not limited to this configuration. Wafers and other manufacturing methods may be used.

It is a perspective view which shows the structure of the inkjet head of 1st Embodiment. In the inkjet head of 1st Embodiment, it is a longitudinal cross-sectional view which shows the piezoelectric material thin film formed into the Si substrate. FIG. 3 is a cross-sectional view for explaining a state in which a piezoelectric thin film is etched in the ink jet head of the first embodiment. It is a perspective view which shows the structure of the inkjet head of 2nd Embodiment. 6 is a cross-sectional view showing a piezoelectric thin film formed on a vibration plate in an ink jet head according to a second embodiment. FIG. It is a cross-sectional view for demonstrating the state in which the piezoelectric thin film is etched in the inkjet head of 2nd Embodiment.

Explanation of symbols

101 Si substrate 102 Individual liquid chamber 103 Nozzle communication port 104 Common liquid chamber 105 Vibration plate 106 Lower electrode 107 Piezoelectric thin film 108 Upper electrode 109 Bulkhead 111 Orifice plate

Claims (7)

A plurality of liquid chambers communicating with discharge ports for discharging the liquid and pressurizing the liquid; a lower electrode provided corresponding to each of the plurality of liquid chambers and stacked in order from the liquid chamber side; and a piezoelectric body A plurality of piezoelectric elements having a film and an upper electrode, and a liquid ejection head in which the lower electrode is provided in a corresponding region between the plurality of liquid chambers,
The piezoelectric film is provided in a region corresponding to the space between the plurality of liquid chambers, and a region corresponding to the space between the plurality of liquid chambers is smaller in thickness than a region corresponding to the liquid chamber. A liquid discharge head characterized by covering all of the lower electrode.   The liquid ejection head according to claim 1, wherein the piezoelectric film is formed by laminating a plurality of piezoelectric films having different etching rates in the film thickness direction. A plurality of liquid chambers communicating with discharge ports for discharging the liquid and pressurizing the liquid; a lower electrode provided corresponding to each of the plurality of liquid chambers and stacked in order from the liquid chamber side; and a piezoelectric body A plurality of piezoelectric elements each having a film and an upper electrode, wherein the lower electrode is provided up to a corresponding region between the liquid chambers, and at least the lower electrode provided in the region is A method of manufacturing a liquid discharge head that is entirely covered by a body film,
Forming a material film of the piezoelectric film on the lower electrode;
The material film of the piezoelectric film is formed such that a region corresponding to the space between the plurality of liquid chambers of the material film of the piezoelectric film is smaller than a region corresponding to the liquid chamber. Etching a corresponding region between a plurality of liquid chambers;
A method of manufacturing a liquid discharge head, comprising:   The method of manufacturing a liquid ejection head according to claim 3, wherein the etching is dry etching, and the lower electrode contains Pt.   In the forming step, the material film is formed by laminating a plurality of piezoelectric films having different etching rates in the film thickness direction, and in the etching step, the piezoelectric film on the liquid chamber side in the material film The method of manufacturing a liquid discharge head according to claim 3, wherein etching is performed using as an etching stop layer.   6. The method of manufacturing a liquid ejection head according to claim 5, wherein the piezoelectric film to be etched is in an uncrystallized state in the material film, and the piezoelectric film to be the etching stop layer is in a crystallized state.   The method of manufacturing a liquid discharge head according to claim 3, further comprising a step of crystallizing the piezoelectric film in the non-crystallized state after the forming step.

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