JP2008062451A - Method for manufacturing liquid jetting head, liquid jetting head and liquid jetting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a liquid jetting head prevented from being clogged with foreign substances and improves yield and reliability, a liquid jetting head and a liquid jetting apparatus. <P>SOLUTION: The method for manufacturing the liquid jetting head comprises a process wherein the end face of a penetrating part 51 side of a vibrating plate 50 is formed so as to make the section a round shape, and one face of a region opposing to a communicating part 13 of a flow path forming substrate 10 becomes between the depth direction of the penetrating part of the vibrating plate, a process for forming a piezoelectric element 300 on the vibrating plate, a process for forming a lead electrode 90 and for sealing the penetrating part with a wiring layer 190, a process for connecting a reserver forming substrate 30 on one face side of the flow path forming substrate, a process for forming a pressure generating room 12 and a communicating part on the flow path forming substrate and exposing a part of the communicating part side of the penetrating part, a process for forming a protective film 16 on the inner face of the flow path forming substrate and the inner face of the penetrating part, a process for removing the protective film on a wiring layer, and a process for communicating the reserver part 31 with the communicating part by removing the wiring layer to form a reserver 100. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a liquid ejecting head that ejects liquid from a nozzle opening, a liquid ejecting head, and a liquid ejecting apparatus, and more particularly to a method for manufacturing an ink jet recording head that ejects ink as liquid, an ink jet recording head, and ink jet recording. Relates to the device.

  As an ink jet recording head that is a liquid ejecting head, for example, a pressure generating chamber that communicates with a nozzle opening and is partitioned by a partition, and an ink supply path and ink that communicate with a pressure generating chamber partitioned by an extended partition A flow path forming substrate having a communication path communicating with the supply path, a communication portion communicating with the communication path and communicating with the plurality of pressure generating chambers, and a piezoelectric element formed on one side of the flow path forming substrate There is a device including an element and a reservoir forming substrate having a reservoir portion which is joined to a surface of the flow path forming substrate on the piezoelectric element side and forms a part of the reservoir together with a communication portion (see, for example, Patent Document 1).

  In addition, as a method for manufacturing an ink jet recording head, a reservoir forming substrate having a reservoir portion on one side of the flow path forming substrate after forming a boron dope layer (an isolation layer of the present invention) on one surface of the flow path forming substrate. After that, the pressure generating chamber and the communication portion are formed by anisotropically etching the flow path forming substrate from the other surface side, and then the reservoir portion and the communication portion are communicated with each other through the boron dope layer. Has been proposed (see, for example, Patent Document 2). By forming the ink jet recording head by such a manufacturing method, when the pressure generating chamber and the communication portion are formed on the flow path forming substrate, the etching solution is supplied by the isolation layer via the communication portion and the reservoir portion. The reservoir forming substrate is prevented from being etched.

  Furthermore, an ink jet recording head has been proposed in which a liquid-resistant protective film made of tantalum oxide is provided on the inner surface of a flow path forming substrate such as a pressure generating chamber (see, for example, Patent Document 3).

JP 2004-186527 A (FIGS. 2-4, pages 6-7) Japanese Patent Laying-Open No. 2005-219243 (FIGS. 3-5, pages 6-8) JP 2004-262225 A (FIG. 2, pages 12-13)

  However, when the protective film is formed after penetrating the communication portion and the reservoir portion when the protective film of Patent Literature 3 is provided using the method of manufacturing the ink jet recording head of Patent Literature 2, A protective film is also formed on the upper surface side, and the protective film covers the wiring of the driving circuit provided on the reservoir formation substrate, which may cause a problem of poor connection between the driving circuit and the wiring. There is a problem that a process for removing the film is necessary and the manufacturing cost increases.

  For this reason, when the protective film is formed in a state where the communication portion of the flow path forming substrate and the reservoir portion of the reservoir forming substrate are separated by the isolation layer, the protective film on the wiring layer needs to be peeled off before penetrating the wiring layer. is there.

  However, since the protective film formed on the isolation layer is provided so as to extend in the surface direction from the pressure generating chamber side, the protective film is provided in the through portion of the diaphragm that communicates the communication portion and the reservoir portion. There is a problem that it is difficult to break at the boundary, and a residue in which a part of the protective film protrudes like a bowl in the penetrating portion is generated, or a crack or the like is generated in the protective film due to a failure to break.

  Further, such a protective film residue is easily peeled off, and the clogging of the nozzle opening occurs due to the peeled off protective film residue, resulting in a problem that yield and reliability are lowered.

  Such a problem exists not only in a method for manufacturing an ink jet recording head that discharges ink, but also in a method for manufacturing another liquid ejecting head that discharges liquid other than ink.

  In view of such circumstances, the present invention provides a method of manufacturing a liquid ejecting head, a liquid ejecting head, and a liquid ejecting apparatus that can reliably prevent ejection defects such as clogging due to foreign matters and improve yield and reliability. The task is to do.

According to a first aspect of the present invention for solving the above problems, there is provided a pressure generating chamber that communicates with a nozzle opening that ejects liquid, and a reservoir that communicates with a plurality of pressure generating chambers and serves as a common liquid chamber of the pressure generating chamber. A diaphragm having a penetrating portion opened in a region facing the communicating portion is formed on one surface side of the flow path forming substrate provided with a communicating portion constituting a part, and the penetrating portion of the diaphragm The end face on the side is formed so that the cross section thereof is circular, and one surface of the region facing the communication part of the flow path forming substrate is between the depth direction of the through part of the diaphragm. Forming the piezoelectric element including a lower electrode, a piezoelectric layer, and an upper electrode on the diaphragm, and sealing the penetrating portion on the one surface side of the flow path forming substrate. A step of forming an isolation layer; and A step of joining a reservoir forming substrate having a reservoir portion that forms a part to the one surface side of the flow path forming substrate, and until the diaphragm and the isolation layer are exposed from the other surface side of the flow path forming substrate. Forming the pressure generating chamber and the communicating portion by wet etching, exposing a part of the penetrating portion on the communicating portion side, the pressure generating chamber of the flow path forming substrate, the communicating portion, and A step of forming a protective film made of a liquid-resistant material on the exposed inner surface of the penetrating part, a step of peeling off and removing the protective film on the isolation layer, and removing the isolation layer And a step of forming the reservoir by communicating the reservoir portion and the communicating portion.
In the first aspect, since foreign matter such as machining residue is not generated when the reservoir portion and the communication portion are communicated with each other, defective discharge such as nozzle clogging due to foreign matter such as machining residue can be prevented. . In particular, the contact with the inner surface of the penetrating portion of the protective film is improved, and the protective film can be bent at the boundary between the inner surface of the penetrating portion and the separating layer, so that the protective film is provided in a planar shape. Only the protective film can be easily removed. Then, when the protective film is removed, it is possible to prevent the residue protruding in a bowl shape from being generated, and the residue is peeled off at the time of liquid inflow and the nozzle opening is clogged by the peeled residue. Can be prevented.

According to a second aspect of the present invention, in the step of forming the isolation layer, a lead electrode drawn from the piezoelectric element is formed on the one surface side of the flow path forming substrate, and from the same layer as the lead electrode. However, the lead electrode is provided with a step of forming the isolation layer composed of a discontinuous wiring layer. In the liquid jet head manufacturing method according to the first aspect, the lead electrode is provided.
In the second aspect, since the lead electrode and the isolation layer made of the wiring layer can be formed simultaneously, the manufacturing process can be simplified and the cost can be reduced.

According to a third aspect of the present invention, in the step of forming the protective film, the protective film is formed by bending at the boundary between the inner surface of the penetrating portion and the isolation layer, and the protective film is removed. In the method of manufacturing a liquid jet head according to the first or second aspect, the protective film is broken at a bent boundary.
In the third aspect, only the protective film provided in a planar shape on the isolation layer can be easily removed.

According to a fourth aspect of the present invention, the flow path forming substrate is made of a silicon single crystal substrate, and in the step of forming the diaphragm, a silicon nitride film is formed in a region where the through portion of the flow path forming substrate is provided. In the method of manufacturing a liquid jet head according to any one of the first to third aspects, the diaphragm is made of silicon oxide by forming and thermally oxidizing the flow path forming substrate.
In the fourth aspect, the end surface of the diaphragm on the penetrating portion side can be easily and reliably formed so that the cross section is circular.

According to a fifth aspect of the present invention, in the method of manufacturing a liquid jet head according to any one of the first to fourth aspects, an oxide or a nitride is used as a material for the protective film.
In the fifth aspect, it is possible to reliably prevent the inner surfaces of the pressure generation chamber, the communication portion, and the like from being eroded by the supplied liquid.

According to a sixth aspect of the present invention, in the method for manufacturing a liquid jet head according to the fifth aspect, tantalum oxide is used as the material of the protective film.
In the sixth aspect, it is possible to reliably prevent the inner surfaces of the pressure generation chamber, the communication portion, and the like from being eroded by the supplied liquid.

According to a seventh aspect of the present invention, in the step of peeling off the protective film, after forming a peeling layer whose internal stress is compressive stress on the protective film, the peeling layer is peeled off together with the peeling layer. In the method of manufacturing a liquid jet head according to any one of the first to sixth aspects, the protective film on the isolation layer is peeled off.
In the seventh aspect, the protective film on the isolation layer can be more easily and reliably removed by the release layer.

According to an eighth aspect of the present invention, in the liquid jet head according to the seventh aspect, the adhesion force between the release layer and the protective film is greater than the adhesion force between the protective film and the isolation layer. Is in the way.
In the eighth aspect, since the release layer and the protective film are in good contact, the protective film on the isolation layer can be more easily and reliably removed together with the release layer.

According to a ninth aspect of the present invention, in the method of manufacturing a liquid jet head according to any one of the sixth to eighth aspects, the titanium tungsten is used as a material for the release layer.
In the ninth aspect, by forming the release layer with a predetermined material, the protective film on the isolation layer can be more easily and reliably removed together with the release layer.

According to a tenth aspect of the present invention, the method further includes the step of removing a part of the isolation layer exposed in the communication portion in the thickness direction before the step of forming the protective film. The method of manufacturing a liquid jet head according to any one of?
In the tenth aspect, since the adhesion between the isolation layer and the protective film is weakened, the protective film on the isolation layer can be removed more satisfactorily and reliably.

In an eleventh aspect of the present invention, the isolation layer comprises an adhesion layer and a metal layer formed on the adhesion layer, and the surface of the isolation layer is light-etched before the step of forming the protective film. Then, at least the adhesive layer is removed, and the liquid jet head manufacturing method according to the tenth aspect is provided.
In the eleventh aspect, the light-etching of the isolation layer removes a part of the metal layer in which the adhesion layer has diffused together with the adhesion layer, thereby more reliably weakening the adhesion between the isolation layer and the protective film. Therefore, the protective film on the isolation layer can be removed more satisfactorily and reliably.

According to a twelfth aspect of the present invention, there is provided a flow path forming substrate provided with a pressure generation chamber communicating with a nozzle opening for ejecting liquid, and a communication portion serving as a common liquid chamber of the plurality of pressure generation chambers, A diaphragm provided on one side of the path forming substrate, a piezoelectric element comprising a lower electrode, a piezoelectric layer and an upper electrode provided on the diaphragm, and bonded to the piezoelectric element side of the flow path forming substrate And a reservoir forming substrate provided with a reservoir portion that communicates with the communicating portion and forms a part of a common liquid chamber, and the diaphragm and the reservoir portion communicate with each other. The liquid ejecting head is characterized in that a penetrating portion is provided and a cross section of an end face of the diaphragm on the penetrating portion side is circular.
In the twelfth aspect, it is possible to improve the contact of the protective film to the inner surface of the penetrating portion, and it is possible to prevent the protective film from generating a residue that protrudes like a bowl. It is possible to prevent the residue from peeling off and clogging of the nozzle opening due to the peeled residue.

In a thirteenth aspect of the present invention, a protective film having liquid resistance is provided on the inner surface of the pressure generating chamber and the communication portion of the flow path forming substrate, and the protective film is provided with the vibration. The liquid jet head according to a twelfth aspect is characterized in that the plate is continuously provided from a surface of the plate on the pressure generating chamber side to a part of the inner surface of the penetrating portion on the side of the communicating portion.
In the thirteenth aspect, the boundary portion between the flow path forming substrate and the diaphragm can be covered with the protective film, and the boundary portion can be reliably prevented from being eroded by the liquid.

According to a fourteenth aspect of the present invention, there is provided a liquid ejecting apparatus including the liquid ejecting head according to the twelfth or thirteenth aspect.
In the fourteenth aspect, a liquid ejecting apparatus with improved reliability can be realized.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view showing a schematic configuration of an ink jet recording head which is an example of a liquid jet head according to Embodiment 1 of the present invention. FIG. 2 is a plan view of FIG. It is a figure and an important section expanded sectional view.

  As shown in the drawing, the flow path forming substrate 10 is made of a silicon single crystal substrate having a crystal plane orientation of (110) in this embodiment, and one surface thereof has a thickness of 0. An elastic film 50 of 5 to 2 μm is formed.

  In the flow path forming substrate 10, pressure generating chambers 12 partitioned by a plurality of partition walls 11 are arranged in parallel in the width direction (short direction) by anisotropic etching from the other surface side. In addition, an ink supply path 14 and a communication path 15 are partitioned by a partition wall 11 on one end side in the longitudinal direction of the pressure generating chamber 12 of the flow path forming substrate 10. In addition, a communication portion 13 constituting a part of the reservoir 100 serving as an ink chamber (liquid chamber) common to the pressure generation chambers 12 is formed at one end of the communication passage 15. That is, the flow path forming substrate 10 is provided with a liquid flow path including a pressure generation chamber 12, a communication portion 13, an ink supply path 14, and a communication path 15.

  The ink supply path 14 communicates with one end side in the longitudinal direction of the pressure generation chamber 12 and has a smaller cross-sectional area than the pressure generation chamber 12. For example, in the present embodiment, the ink supply path 14 has a width smaller than the width of the pressure generation chamber 12 by narrowing the flow path on the pressure generation chamber 12 side between the reservoir 100 and each pressure generation chamber 12 in the width direction. The flow path resistance of the ink flowing into the pressure generating chamber 12 from the communication portion 13 is kept constant. As described above, in this embodiment, the ink supply path 14 is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path. Further, each communication path 15 communicates with the side of the ink supply path 14 opposite to the pressure generation chamber 12 and has a larger cross-sectional area than the width direction (short direction) of the ink supply path 14. In this embodiment, the communication passage 15 is formed with the same cross-sectional area as the pressure generation chamber 12.

  In other words, the flow path forming substrate 10 is connected to the pressure generation chamber 12, the ink supply path 14 having a smaller cross-sectional area in the short direction of the pressure generation chamber 12, the ink supply path 14, and the ink supply. A communication passage 15 having a cross-sectional area larger than the cross-sectional area in the short direction of the path 14 is provided by being partitioned by a plurality of partition walls 11.

Here, a material having ink resistance, for example, tantalum pentoxide (Ta ₂ O ₅ ) is formed on the inner wall surfaces of the pressure generation chamber 12, the communication portion 13, the ink supply path 14, and the communication path 15 of the flow path forming substrate 10. A protective film 16 made of tantalum oxide or the like is provided with a thickness of about 50 nm. The ink resistance referred to here is etching resistance against alkaline ink.

The material of the protective film 16 is not limited to tantalum oxide, and depending on the pH value of the ink used, for example, zirconium oxide (ZrO ₂ ), nickel (Ni), chromium (Cr) or the like is used. Also good.

  Further, in the present embodiment, the elastic film 50 that is a diaphragm is provided with a penetrating portion 51 that communicates the communicating portion 13 and a reservoir portion 31 of a reservoir forming substrate 30 described later in detail. The end face of the elastic film 50 on the penetrating part 51 side is provided with a circular cross section, and the protective film 16 is provided on the inner surface of the penetrating part 51 on the communication part 13 side. That is, the protective film 16 is continuously provided from one surface of the elastic film 50 on the pressure generating chamber 12 side to the inner surface of the penetrating part 51 on the communication part 13 side. As described above, the protective film 16 is provided on the inner surface of the penetrating part 51 of the elastic film 50, but the end face of the elastic film 50 on the penetrating part 51 side is provided with a circular cross section. It is possible to prevent the protective film 16 from peeling off. Further, since the protective film 16 is provided so as to cover the boundary between the flow path forming substrate 10 and the elastic film 50, the ink contacts the boundary portion and the flow path forming substrate 10 is eroded by the ink. Can be reliably prevented.

  Further, on the opening surface side of the flow path forming substrate 10, a nozzle plate 20 having a nozzle opening 21 communicating with the vicinity of the end of each pressure generating chamber 12 on the side opposite to the ink supply path 14 is provided with an adhesive. Or a heat-welded film or the like. The nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, stainless steel, or the like.

  On the other hand, the elastic film 50 made of silicon dioxide and having a thickness of, for example, about 1.0 μm is formed on the side opposite to the opening surface of the flow path forming substrate 10 as described above. Further, the elastic film 50 is made of a lower electrode film 60 having a thickness of about 0.1 to 0.5 μm and lead zirconate titanate (PZT) which is an example of a piezoelectric film. A piezoelectric layer 70 having a thickness of about 1.1 μm and an upper electrode film 80 having a thickness of, for example, about 0.05 μm are laminated by a process described later to constitute the piezoelectric element 300. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In this case, a portion that is configured by any one of the patterned electrodes and the piezoelectric layer 70 and in which piezoelectric distortion is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion 320. In this embodiment, the lower electrode film 60 is a common electrode of the piezoelectric element 300, and the upper electrode film 80 is an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for the convenience of the drive circuit and wiring. In any case, the piezoelectric active part 320 is formed for each pressure generating chamber 12. In addition, here, the piezoelectric element 300 and the diaphragm that is displaced by driving the piezoelectric element 300 are collectively referred to as an actuator device. In the above-described example, the elastic film 50 acts as a diaphragm, but another film, for example, an insulator film made of zirconium oxide or the like is provided on the elastic film 50, and the elastic film 50 and the insulator film are connected to each other. It is good also as a diaphragm.

  In addition, a lead electrode 90 composed of a wiring layer 190 including an adhesion layer 91 and a metal layer 92 is connected to the upper electrode film 80 of each piezoelectric element 300, and each piezoelectric element is connected via the lead electrode 90. A voltage is selectively applied to the element 300.

  As will be described in detail later, the diaphragm in the region corresponding to the peripheral edge of the opening of the communication portion 13, that is, the elastic film 50, also includes the adhesion layer 91 and the metal layer 92, but is discontinuous with the lead electrode 90. A wiring layer 190 is present.

  Further, a reservoir forming substrate 30 having a reservoir portion 31 constituting at least a part of the reservoir 100 is joined to the surface of the flow path forming substrate 10 on the piezoelectric element 300 side. In this embodiment, the flow path forming substrate 10 and the reservoir forming substrate 30 are bonded using the adhesive 35. The reservoir portion 31 of the reservoir forming substrate 30 communicates with the communication portion 13 through a through portion 51 provided in the elastic film 50, and the reservoir 100 is formed by the reservoir portion 31 and the communication portion 13.

  In addition, a piezoelectric element holding portion 32 is provided in a region facing the piezoelectric element 300 of the reservoir forming substrate 30. Since the piezoelectric element 300 is formed in the piezoelectric element holding portion 32, the piezoelectric element 300 is protected in a state hardly affected by the external environment. In addition, the piezoelectric element holding | maintenance part 32 may be sealed and does not need to be sealed. Examples of the material of the reservoir forming substrate 30 include glass, ceramic material, metal, resin, and the like, but it is preferable that the reservoir forming substrate 30 be formed of a material substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10. In this embodiment, the silicon single crystal substrate made of the same material as the flow path forming substrate 10 is used.

  A drive circuit 200 for driving the side-by-side piezoelectric elements 300 is fixed on the reservoir forming substrate 30. For example, a circuit board or a semiconductor integrated circuit (IC) can be used as the drive circuit 200. The drive circuit 200 and the lead electrode 90 are electrically connected via a connection wiring 210 made of a conductive wire such as a bonding wire.

  Furthermore, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto a region corresponding to the reservoir portion 31 of the reservoir forming substrate 30. The sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm). The sealing film 41 seals one surface of the reservoir unit 31. Yes. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SUS) having a thickness of 30 μm). Since the region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with a flexible sealing film 41. Has been.

  In such an ink jet recording head of this embodiment, ink is taken in from an external ink supply unit (not shown), filled with ink from the reservoir 100 to the nozzle opening 21, and then in accordance with a recording signal from the drive circuit 200. By applying a voltage between each of the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generation chambers 12 to bend and deform the piezoelectric element 300 and the diaphragm, the pressure in each pressure generation chamber 12 increases. Ink is ejected from the nozzle openings 21.

  Hereinafter, a method for manufacturing such an ink jet recording head will be described with reference to FIGS. 3 to 7 are cross-sectional views in the longitudinal direction of the pressure generating chamber showing the method of manufacturing the ink jet recording head.

First, as shown in FIG. 3A, a silicon nitride film 52 made of, for example, silicon nitride (Si _x N _y ) is formed in a region where the through portion 51 of the flow path forming substrate wafer 110 that is a silicon wafer is formed. Form. In the present embodiment, the silicon nitride film 52 is formed by forming silicon nitride over the entire surface of the flow path forming substrate wafer 110 and then patterning the silicon nitride film 52 into a predetermined shape. However, the present invention is not particularly limited thereto. A mask that opens to a desired region may be provided on the surface of the formation substrate wafer 110, and only the region exposed by the opening of the mask may be thermally nitrided.

  Next, as shown in FIG. 3 (b), the flow path forming substrate wafer 110 is thermally oxidized in a diffusion furnace at about 1100 ° C., and silicon dioxide constituting the elastic film 50 on the surface of the flow path forming substrate wafer 110. A film 53 is formed. At this time, since a part of the surface of the flow path forming substrate wafer 110 is covered with the silicon nitride film 52, the elastic film 50 is formed in a region other than the silicon nitride film 52. Thereafter, as shown in FIG. 3C, the silicon nitride film 52 is removed, thereby forming an elastic film 50 (silicon dioxide film 53) in which the penetrating portion 51 is formed. That is, in this embodiment, the elastic film 50 is formed by LOCOS (Local Oxidation of Silicon).

  The elastic film 50 thus formed has a circular cross section at the end face on the penetrating part 51 side, and the surface of the flow path forming substrate wafer 110 is between the thickness direction of the elastic film 50 (the penetrating part). 51 in the depth direction). That is, the penetration part 51 is formed in a state in which the inner surface is exposed partway in the depth direction on the opening side.

  In the present embodiment, a silicon wafer having a relatively thick and high rigidity of about 625 μm is used as the flow path forming substrate wafer 110.

  Next, as shown in FIG. 4A, for example, after the lower electrode film 60 is formed by laminating platinum and iridium on the elastic film 50, the lower electrode film 60 is patterned into a predetermined shape. Next, as shown in FIG. 4B, for example, a piezoelectric layer 70 made of lead zirconate titanate (PZT) or the like and an upper electrode film 80 made of, for example, iridium are bonded to the wafer 110 for flow path forming substrate. The piezoelectric element 300 is formed by patterning the piezoelectric layer 70 and the upper electrode film 80 in regions facing the pressure generation chambers 12.

The material of the piezoelectric layer 70 constituting the piezoelectric element 300 is, for example, a ferroelectric piezoelectric material such as lead zirconate titanate (PZT), or niobium, nickel, magnesium, bismuth, yttrium, or the like. A relaxor ferroelectric or the like to which a metal is added is used. The composition may be appropriately selected in consideration of the characteristics, application, etc. of the piezoelectric element 300. For example, PbTiO ₃ (PT), PbZrO ₃ (PZ), Pb (Zr _x Ti _1-x ) O ₃ (PZT) ), Pb (Mg _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PMN-PT), Pb (Zn _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PZN-PT), Pb (Ni ₁ ) _{/ 3 Nb 2/3) O 3 -PbTiO} 3 (PNN-PT), Pb (In 1/2 Nb 1/2) O 3 -PbTiO 3 (PIN-PT), Pb (Sc 1/2 Ta 1/2 _{) O 3 -PbTiO 3 (PST-} PT), Pb (Sc 1/2 Nb 1/2) O 3 -PbTiO 3 (PSN-PT), BiScO 3 -PbTiO 3 (BS-PT), BiYbO 3 -PbTiO 3 (BY PT), and the like.

  The method for forming the piezoelectric layer 70 is not particularly limited. For example, in this embodiment, a so-called sol in which a metal organic substance is dissolved and dispersed in a catalyst is applied, dried, gelled, and further fired at a high temperature. The piezoelectric layer 70 was formed by using a so-called sol-gel method for obtaining a piezoelectric layer 70 made of an oxide. The method for manufacturing the piezoelectric layer 70 is not limited to the sol-gel method, and for example, a MOD (Metal-Organic Decomposition) method or a sputtering method may be used.

  Next, as shown in FIG. 4C, the lead electrode 90 is formed. Specifically, first, the metal layer 92 is formed over the entire surface of the flow path forming substrate wafer 110 via the adhesion layer 91, and the wiring layer 190 including the adhesion layer 91 and the metal layer 92 is formed. Then, a mask pattern (not shown) made of, for example, a resist or the like is formed on the wiring layer 190, and the metal layer 92 and the adhesion layer 91 are patterned for each piezoelectric element 300 through the mask pattern, thereby leading to the lead electrode. 90 is formed. At this time, a wiring layer 190 discontinuous with the lead electrode 90 is left in a region facing the through portion 51, and the through portion 51 is sealed by the wiring layer 190. That is, in the present embodiment, an isolation layer that separates the reservoir portion 31 and the communication portion 13 is formed of the same layer as the lead electrode 90, but an independent wiring layer 190 that is discontinuous with the lead electrode 90 is formed. Thereby, the wiring layer 190 which is an isolation layer can be formed simultaneously with the lead electrode 90, and the manufacturing process can be simplified and the cost can be reduced. The isolation layer is not particularly limited to this, and for example, after the lead electrode 90 is formed, an isolation layer such as a metal material or a resin material may be separately formed.

  When the wiring layer 190 as an isolation layer is formed in this way, the wiring layer 190 is formed on the one surface side of the elastic film 50, the exposed inner surface of the through portion 51, and the flow path forming substrate wafer 110 in the through portion 51. Are provided continuously on one side of the. That is, the wiring layer 190 is provided only halfway in the depth direction of the through portion 51, and as will be described in detail later, when the communication portion 13 is formed on the flow path forming substrate wafer 110, the through portion 51 is provided. A part of the communication part 13 side is exposed.

  Here, the main material of the metal layer 92 is not particularly limited as long as it is a material having relatively high conductivity, and examples thereof include gold (Au), platinum (Pt), aluminum (Al), and copper (Cu). In this embodiment, gold (Au) is used. The material of the adhesion layer 91 may be any material that can ensure the adhesion of the metal layer 92. Specifically, titanium (Ti), titanium tungsten compound (TiW), nickel (Ni), chromium (Cr ) Or a nickel chromium compound (NiCr), etc., and in this embodiment, a titanium tungsten compound (TiW) is used.

  Next, as illustrated in FIG. 5A, the reservoir forming substrate wafer 130 is bonded onto the flow path forming substrate wafer 110 with an adhesive 35. Here, a reservoir section 31, a piezoelectric element holding section 32, and the like are formed in advance on the reservoir forming substrate wafer 130. The reservoir forming substrate wafer 130 is, for example, a silicon wafer having a thickness of about 400 μm, and the rigidity of the flow path forming substrate wafer 110 is significantly improved by bonding the reservoir forming substrate wafer 130. Become.

Next, as shown in FIG. 5B, after the flow path forming substrate wafer 110 is polished to a certain thickness, the flow path forming substrate wafer 110 is further etched to a predetermined thickness by wet etching with hydrofluoric acid. To. For example, in this embodiment, the flow path forming substrate wafer 110 is processed to have a thickness of about 70 μm by polishing and wet etching. Next, as shown in FIG. 5C, a mask film 54 made of, for example, silicon nitride (Si _x N _y ) is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, as shown in FIG. 6A, the flow path forming substrate wafer 110 is anisotropically etched (wet etching) through the mask film 54, so that the flow path forming substrate wafer 110 has a liquid flow path, In the present embodiment, the pressure generation chamber 12, the communication part 13, the ink supply path 14, the communication path 15 and the like are formed. Specifically, the pressure is obtained by etching the flow path forming substrate wafer 110 with an etching solution such as an aqueous potassium hydroxide (KOH) solution until the elastic film 50 and the adhesion layer 91 (metal layer 92) are exposed. The generation chamber 12, the communication part 13, the ink supply path 14, and the communication path 15 are formed simultaneously.

  Further, when the liquid flow path such as the pressure generation chamber 12 is formed in this way, the through portion 51 is sealed by the wiring layer 190 including the adhesion layer 91 and the metal layer 92, and thus the through portion 51 is interposed therebetween. The etching solution does not flow into the reservoir forming substrate wafer 130 side. As a result, the etching solution does not adhere to the connection wiring (not shown) provided on the surface of the reservoir forming substrate wafer 130, and the occurrence of defects such as disconnection can be prevented. Further, there is no possibility that the etchant enters the reservoir portion 31 and the reservoir forming substrate wafer 130 is etched.

When forming such a pressure generating chamber 12 or the like, the surface of the reservoir forming substrate wafer 130 opposite to the flow path forming substrate wafer 110 is formed on an anti-alkali material such as PPS (polyphenylene sulfide). ), PPTA (polyparaphenylene terephthalamide) or the like may be further sealed. Thereby, defects such as disconnection of wiring provided on the surface of the reservoir forming substrate wafer 130 can be more reliably prevented.

  When the pressure generating chamber 12 or the like is formed on the flow path forming substrate wafer 110 as described above, the wiring layer 190 that seals the through portion 51 is provided only halfway in the depth direction of the through portion 51 as described above. Therefore, a part of the penetrating part 51 on the communication part 13 side is exposed on the elastic film 50 side of the flow path forming substrate wafer 110. The exposed inner surface of the penetrating part 51 has a circular cross section.

  Next, as shown in FIG. 6B, a part of the wiring layer 190 in the penetrating part 51 is removed by wet etching (light etching) from the communicating part 13 side. That is, the adhesion layer 91 exposed to the communication portion 13 side and a part of the metal layer 92 where the adhesion layer 91 is diffused are removed by etching. As will be described in detail later, the adhesion between the protective film 16 formed on the wiring layer 190 and the wiring layer 190 in a later step is weakened, and the protective film 16 on the wiring layer 190 is easily peeled off.

  Next, the mask film 54 on the surface of the flow path forming substrate wafer 110 is removed, and as shown in FIG. 6C, for example, a material having liquid resistance (ink resistance) such as oxide or nitride, In the present embodiment, the protective film 16 made of tantalum pentoxide is formed by a CVD method or the like.

  At this time, since a part of the penetration part 51 in the depth direction is exposed on the elastic film 50 side of the communication part 13, the protective film 16 is formed from one surface of the elastic film 50 on the pressure generation chamber 12 side. The exposed inner surface of the penetrating part 51 and the wiring layer 190 are continuously provided. As a result, the protective film 16 is bent at the boundary between one surface of the elastic film 50 on the pressure generating chamber 12 side and the inner surface of the penetrating portion 51, and is bent at the boundary between the inner surface of the penetrating portion 51 and the wiring layer 190. Provided.

  Moreover, since the cross section of the exposed inner surface of the penetrating portion 51 is provided in a circular shape, the contact of the protective film 16 is improved.

  When the protective film 16 is formed in this way, since the through portion 51 is sealed by the wiring layer 190, the protective film 16 is formed on the outer surface of the reservoir forming substrate wafer 130 via the through portion 51. There is nothing. Therefore, the protective film 16 is not formed on the surface of the reservoir forming substrate wafer 130 on which the connection wiring and the like are formed, so that it is possible to prevent the occurrence of poor connection of the drive circuit 200 and the like, and an extra protective film The process of removing 16 is unnecessary, and the manufacturing process can be simplified and the manufacturing cost can be reduced.

  Next, as shown in FIG. 7, a release layer 17 made of a high stress material is formed on the protective film 16 by, for example, a CVD method. The release layer 17 preferably has a compressive stress as an internal stress, and particularly preferably a compressive stress of 80 MPa or more. In addition, the release layer 17 is preferably made of a material that has a greater adhesive force with the protective film 16 than an adhesive force between the protective film 16 and the wiring layer 190. In this embodiment, a titanium tungsten compound (TiW) is used as the material of the release layer 17.

  When the release layer 17 made of a high-stress material and having high adhesion to the protective film 16 is formed on the protective film 16, the protective film 16 formed on the wiring layer 190 starts to peel off due to the stress of the release layer 17. . Then, as shown in FIG. 8A, the peeling layer 17 is removed by wet etching, so that the protective film 16 on the wiring layer 190 is completely removed together with the peeling layer 17.

  At this time, the protective film 16 has good contact with the inner surface where the cross section of the penetrating portion 51 is provided in a circular shape, and the protective film 16 is a region provided in a planar shape on the inner surface of the penetrating portion 51 and the wiring layer 190. Therefore, the protective film 16 is broken at the bent region, and only the protective film 16 on the wiring layer 190 can be removed reliably.

  That is, if an attempt is made to break a region where the protective film 16 is provided in a planar shape and is not bent, the protective film 16 is cracked or a residue protruding like a bowl is generated. The residue protruding in a bowl shape of the protective film 16 in this way is easily peeled off particularly when the ink flows in, and the clogging of the nozzle opening 21 occurs due to the peeled residue. However, as in the present invention, by breaking the protective film 16 in the bent region, it is possible to prevent residue and cracks protruding in a bowl shape from occurring, and to prevent clogging of the nozzle opening 21 and the like. Thus, the yield can be improved and the reliability can be improved.

  In the present embodiment, a part of the wiring layer 190 provided in the penetrating part 51 on the side of the communication part 13 side, that is, the adhesion layer 91 and the metal layer 92 in which the adhesion layer 91 is diffused are removed in the above-described process. Therefore, the adhesion between the wiring layer 190 and the protective film 16 is weak, and the protective film 16 can be more easily peeled from the wiring layer 190.

  After removing the protective film 16 on the wiring layer 190 in this way, as shown in FIG. 8B, the wiring layer 190 is removed by wet etching from the communicating portion 13 side, and the through portion 51 is removed. Open. At this time, since the protective film 16 is not formed on the wiring layer 190, the protective film 16 does not interfere with the wet etching of the wiring layer 190.

  Therefore, the wiring layer 190 can be easily and reliably removed by wet etching to open the through portion 51. That is, according to the manufacturing method of the present invention, unlike the conventional mechanical processing, foreign matter such as processing residue does not occur. Accordingly, it is possible to reliably prevent the machining residue from remaining in the ink flow paths such as the pressure generation chamber 12 and the communication portion 13 and the occurrence of defective discharge such as nozzle clogging due to the remaining machining residue. Further, since the protective film 16 can be prevented from protruding and remaining in the shape of a bowl on the wiring layer 190 side, the wiring layer 190 can be reliably removed by etching the wiring layer 190 satisfactorily.

  Thereafter, unnecessary portions of the flow path forming substrate wafer 110 and the reservoir forming substrate wafer 130 are removed by cutting, for example, by dicing. The nozzle plate 20 having the nozzle openings 21 is bonded to the surface of the flow path forming substrate wafer 110 opposite to the reservoir forming substrate wafer 130, and the compliance substrate 40 is attached to the reservoir forming substrate wafer 130. The ink jet recording head having the above-described structure is manufactured by bonding and dividing the flow path forming substrate wafer 110 and the like into a single chip size flow path forming substrate 10 as shown in FIG.

  As described above, according to the manufacturing method of the present embodiment, the end surface of the elastic film 50 on the penetrating part 51 side is formed in a circular shape in cross section so that the protective film 16 is attached to the inner surface of the penetrating part 51. When the unnecessary protective film 16 on the wiring layer 190 that seals the through portion 51 is removed by forming a bent region in the protective film 16, the bent region of the protective film 16 is formed. Can be broken, and cracks and residues of the protective film 16 can be prevented. Accordingly, it is possible to surely prevent the occurrence of ejection failure such as clogging of the nozzle openings 21 due to the residue being peeled off when the ink flows in, and the yield can be improved and the reliability can be improved. Can do.

(Other embodiments)
As mentioned above, although Embodiment 1 of this invention was demonstrated, this invention is not limited to embodiment mentioned above. For example, in the first embodiment described above, the piezoelectric element 300 including the elastic film 50, the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80 is formed on one surface side of the flow path forming substrate 10. Although it was made to function as a diaphragm, it is not limited to this in particular, For example, an insulator film made of zirconium oxide (ZrO ₂ ) or the like is formed on the elastic film 50 with a thickness of, for example, about 0.4 μm, The elastic film 50 and the insulator film may function as a diaphragm. Such an insulator film only needs to be provided with a communicating hole penetrating in the thickness direction communicating with the penetrating portion 51, and the end face shape of the communicating hole of the insulator film is not particularly limited.

  For example, in Embodiment 1 described above, the wiring layer 190 including the adhesion layer 91 and the metal layer 92 is illustrated, but the configuration of the wiring layer 190 is not limited to this, and for example, the wiring layer may be only a metal layer. You may make it comprise by. In the above-described embodiment, the protective film 16 on the wiring layer 190 formed in the through-hole 51 is removed by the release layer 17 of the high-stress material, but the method for removing the protective film 16 on the wiring layer 190 is also described. Is not particularly limited. Any removal method can improve the contact of the protective film 16 to the inner surface of the penetrating portion 51 and can be provided with the protective film 16 bent, so that the protective film 16 is broken in the bent region. Thus, cracks and residues can be prevented.

  Further, the ink jet recording head of the first embodiment described above constitutes a part of a recording head unit including an ink flow path communicating with an ink cartridge or the like, and is mounted on the ink jet recording apparatus. FIG. 9 is a schematic view showing an example of the ink jet recording apparatus.

  As shown in FIG. 9, in the recording head units 1A and 1B having the ink jet recording head, cartridges 2A and 2B constituting ink supply means are detachably provided, and a carriage 3 on which the recording head units 1A and 1B are mounted. Is provided on a carriage shaft 5 attached to the apparatus body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.

  The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S which is a recording medium such as paper fed by a paper feed roller (not shown) is wound around the platen 8. It is designed to be transported.

  In the above-described embodiments, the ink jet recording head has been described as an example of the liquid ejecting head. However, the present invention broadly applies to all liquid ejecting heads and ejects liquids other than ink. Of course, the present invention can also be applied to a method of manufacturing a liquid jet head. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (surface emitting displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

FIG. 3 is an exploded perspective view of the recording head according to the first embodiment. 2A and 2B are a plan view and a cross-sectional view of the recording head according to the first embodiment. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. FIG. 5 is an enlarged cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment. 1 is a schematic diagram illustrating an example of an ink jet recording apparatus according to an embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 16 Protective film, 20 Nozzle plate, 21 Nozzle opening, 30 Reservoir formation board | substrate, 31 Reservoir part, 32 Piezoelectric element holding part, 35 Adhesive agent, 40 Compliance board | substrate, 50 Elastic film, 51 Penetration part, 60 Lower electrode film, 70 Piezoelectric layer, 80 Upper electrode film, 90 Lead electrode, 91 Adhesion layer, 92 Metal layer, 100 Reservoir, 110 Flow path forming substrate wafer, 130 Reservoir forming substrate wafer, 190 Wiring layer, 200 driving circuit, 210 driving wiring, 300 piezoelectric element

Claims (14)

Forming a flow path provided with a pressure generating chamber that communicates with a nozzle opening for ejecting liquid and a communication portion that communicates with a plurality of pressure generating chambers and forms a part of a reservoir serving as a common liquid chamber for the pressure generating chambers A diaphragm having a penetrating portion that opens in a region opposite to the communication portion is formed on one surface side of the substrate, and an end surface of the diaphragm on the penetrating portion side is formed to have a circular cross section. And forming one surface of the region facing the communication portion of the flow path forming substrate so as to be between the depth directions of the through portion of the diaphragm;
Forming a piezoelectric element comprising a lower electrode, a piezoelectric layer and an upper electrode on the diaphragm;
Forming an isolation layer for sealing the through portion on the one surface side of the flow path forming substrate;
Bonding a reservoir forming substrate formed with a reservoir portion composing a part of the reservoir in communication with the communicating portion to the one surface side of the flow path forming substrate;
The pressure generating chamber and the communication part are formed by wet etching the flow path forming substrate from the other surface side until the diaphragm and the isolation layer are exposed, and a part of the through part on the communication part side A step of exposing
Forming a protective film made of a material having liquid resistance on the inner surface of the pressure generating chamber, the communicating portion and the exposed through portion of the flow path forming substrate;
Peeling and removing the protective film on the isolation layer;
And a step of forming the reservoir by making the reservoir and the communication portion communicate with each other by removing the isolation layer. In the step of forming the isolation layer, a lead electrode drawn out from the piezoelectric element is formed on the one surface side of the flow path forming substrate, and the lead electrode is made of the same layer as the lead electrode but is discontinuous with the lead electrode. The method of manufacturing a liquid jet head according to claim 1, further comprising: forming the isolation layer made of the wiring layer. In the step of forming the protective film, the protective film is bent at the boundary between the inner surface of the penetrating portion and the isolation layer, and in the step of removing the protective film, at the bent boundary of the protective film. The method of manufacturing a liquid jet head according to claim 1, wherein the liquid jet head is broken. The flow path forming substrate is made of a silicon single crystal substrate, and in the step of forming the diaphragm, a silicon nitride film is formed in a region where the through portion of the flow path forming substrate is provided, and the flow path forming substrate is The method of manufacturing a liquid jet head according to claim 1, wherein the diaphragm made of silicon oxide is formed by thermal oxidation. The method of manufacturing a liquid jet head according to claim 1, wherein an oxide or a nitride is used as a material for the protective film. 6. The method of manufacturing a liquid jet head according to claim 5, wherein tantalum oxide is used as a material for the protective film. In the step of peeling off the protective film, after forming a peeling layer whose internal stress is compressive stress on the protective film, the peeling layer is peeled off to peel off the protective film on the isolation layer together with the peeling layer. The method of manufacturing a liquid jet head according to claim 1, wherein: The method of manufacturing a liquid jet head according to claim 7, wherein an adhesion force between the release layer and the protective film is greater than an adhesion force between the protective film and the isolation layer. The method of manufacturing a liquid jet head according to claim 6, wherein titanium tungsten is used as a material of the release layer. 10. The method according to claim 1, further comprising a step of removing a part in a thickness direction of the isolation layer exposed in the communication portion before the step of forming the protective film. A method for manufacturing a liquid jet head. The isolation layer includes an adhesion layer and a metal layer formed on the adhesion layer, and before the step of forming the protective film, the surface of the isolation layer is light-etched to at least remove the adhesion layer. The method of manufacturing a liquid jet head according to claim 10. A flow path forming substrate provided with a pressure generating chamber communicating with a nozzle opening for ejecting liquid and a communication portion serving as a common liquid chamber of the plurality of pressure generating chambers, and provided on one surface side of the flow path forming substrate And a piezoelectric element comprising a lower electrode, a piezoelectric layer, and an upper electrode provided on the diaphragm, and joined to the piezoelectric element side of the flow path forming substrate to communicate with the communication portion. A reservoir forming substrate provided with a reservoir portion constituting a part of the common liquid chamber,
The diaphragm is provided with a penetrating portion that communicates the communication portion and the reservoir portion, and a cross section of an end surface of the diaphragm on the penetrating portion side is circular. Liquid jet head. A liquid-resistant protective film is provided on the pressure generation chamber of the flow path forming substrate and the inner wall surface of the communication portion, and the protective film is a surface of the diaphragm on the pressure generation chamber side. The liquid ejecting head according to claim 12, wherein the liquid ejecting head is continuously provided from a part of the inner surface of the penetrating part to a part of the communicating part side. A liquid ejecting apparatus comprising the liquid ejecting head according to claim 12.

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