JP2008087271A - Method for manufacturing liquid jet head - Google Patents

Abstract

Discharge failure such as clogging due to foreign matter can be reliably prevented, yield and reliability are improved, and cost is reduced.
A step of forming an insulating film 53 so as to seal a penetrating portion 51, a piezoelectric element is formed on a flow path forming substrate, a separation layer 190 is formed on the insulating film 53, and a protrusion 191 is formed. Forming the pressure forming chamber and the communication portion 13 and exposing the insulating film 53 by wet-etching the flow path forming substrate. The step of exposing the protruding portion 191, the step of removing the insulating film 53 exposed to the communication portion 13 side, the pressure generating chamber of the flow path forming substrate, the inner surface of the communication portion 13, and the isolation layer 190 are liquid-resistant. A step of forming the protective film 16 made of a material having a property, a step of peeling off and removing the protective film 16 on the isolation layer 190, and the reservoir portion 31 and the communication portion 13 by removing the isolation layer 190. Communicate Comprising a step.
[Selection] Figure 9

Description

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

  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, 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.

  Further, as the isolation layer, when the pressure generating chamber and the communication portion are formed by wet etching the flow path forming substrate, it is necessary to use a material having excellent etching resistance, which results in high cost. There is a problem.

  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, it is an object of the present invention to provide a method of manufacturing a liquid ejecting head that can reliably prevent ejection defects such as clogging due to foreign matter, improve yield and reliability, and reduce costs. Let it be an issue.

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. Forming a diaphragm on one surface side of the flow path forming substrate provided with a communication part constituting a part, forming a through part opening in a region opposite to the communication part of the diaphragm, and A step of forming a recess in a region facing the penetrating portion of the flow path forming substrate, and an insulating film having etching resistance when wet etching the flow path forming substrate is provided on the one surface of the flow path forming substrate. Forming the penetrating part on the side to seal,
By forming a piezoelectric element comprising a lower electrode, a piezoelectric layer and an upper electrode in a region corresponding to the pressure generating chamber on the diaphragm of the flow path forming substrate, and forming an isolation layer on the insulating film A step of forming a protruding portion in which the insulating film and the isolation layer protrude toward the communication portion in a region where the communication portion is formed; and a reservoir portion that communicates with the communication portion and forms a part of the reservoir Forming the pressure generating chamber and the communication portion by joining the reservoir forming substrate formed with the one side to the one surface side of the flow path forming substrate and wet-etching the flow path forming substrate from the other surface side. And exposing the insulating film to expose the protruding portion, removing the insulating film exposed to the communicating portion side to form the protruding portion with the isolation layer, and the flow The path forming substrate Forming a protective film made of a liquid-resistant material on the force generation chamber, the inner surface of the communication portion, and the isolation layer; removing the protective film on the isolation layer; and 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 first aspect, when the flow path forming substrate is wet-etched, the through portion is sealed with the insulating film having the etching resistance and the isolation layer, so that the etching solution is stored in the reservoir through the through portion. It is possible to reliably prevent the flow to the forming substrate side, and when the reservoir portion and the communication portion communicate with each other, foreign matter such as machining residue is not generated. Can be prevented. In particular, since the protective film having a region bent along the protruding portion is peeled off, the protective film can be easily and surely broken in the bent region, and the residue protruding in a hook shape on the crack or the penetrating portion side Can be prevented, and clogging of the nozzle opening due to peeling of the residue can be prevented.
In addition, since the insulating film has etching resistance, it is not necessary to use a material having excellent etching resistance as the isolation layer, and the cost can be reduced. Furthermore, since the isolation layer has a role of reinforcing the insulating film, the insulating film can be reliably prevented from being broken by the etching solution.

According to a second aspect of the present invention, the flow path forming substrate is formed of a silicon single crystal substrate, and in the step of forming the diaphragm, the flow path forming substrate is thermally oxidized to the flow path forming substrate side. In the step of forming the diaphragm having an elastic film made of silicon dioxide and forming the insulating film, the flow path forming substrate is thermally oxidized to form the diaphragm made of silicon dioxide provided integrally with the elastic film. In the method of manufacturing a liquid jet head according to the first aspect, an insulating film is formed.
In the second aspect, the diaphragm having the elastic film can be easily formed with high accuracy, and the insulating film can be easily formed.

According to a third aspect of the present invention, in the step of forming the protective film, the protective film is formed on the protruding portion, so that the protective film is formed on the diaphragm in the vicinity of the peripheral portion of the penetrating portion. In the step of forming the first bent portion bent to the communication portion side and the second bent portion bent to the center side of the penetrating portion, and peeling and removing the protective film on the isolation layer, In the method of manufacturing a liquid jet head according to the first or second aspect, the protective film is broken at the first bent portion or the second bent portion.
In the third aspect, the protective film can be broken at the first bent portion or the second bent portion, and generation of a residue can be reliably prevented.

According to a fourth aspect of the present invention, in any of the first to third aspects, in the step of forming the concave portion, the concave portion is formed over a region facing the through portion of the flow path forming substrate. The method of manufacturing a liquid jet head according to any of the above aspects.
In the fourth aspect, a protrusion having a desired shape is formed on the isolation layer, and a region bent in the protective film can be formed, and the protective film can be easily and reliably broken in the bent region. it can.

According to a fifth aspect of the present invention, in the step of forming the recess, the flow path forming substrate is formed by anisotropic etching using the diaphragm having the through portion as a mask. The method of manufacturing a liquid jet head according to any one of aspects 1 to 4.
In the fifth aspect, the recess can be formed easily and with high accuracy, and the manufacturing process can be simplified and the cost can be reduced.

According to a sixth aspect of the present invention, in the method of manufacturing a liquid jet head according to any one of the first to fifth aspects, an oxide or a nitride is used as a material for 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 liquid jet head manufacturing method according to the seventh or eighth aspect, titanium tungsten is used as a material of 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.

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. FIG. 3 is an enlarged cross-sectional view of a main part of FIG.

  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. Here, the ink resistance refers to an etching resistance property with respect to an alkaline ink.

The material of such a protective film 16 is not limited to tantalum oxide, and depending on the pH value of the ink (liquid) used, for example, zirconium oxide (ZrO ₂ ), nickel (Ni), chromium (Cr), etc. May be used. However, when an acidic liquid is used, an acid-resistant protective film is of course used.

  In the present embodiment, the elastic film 50 constituting the diaphragm is provided with a through portion 51 that communicates the communication portion 13 and a reservoir portion 31 of the reservoir forming substrate 30 described later in detail. As shown in FIG. 3, the protective film 16 provided on the elastic film 50 is broken near the opening of the penetrating part 51 of the elastic film 50, and the protective film 16 is broken. The cross section 16a is provided facing the communication portion 13 side. As described above, since the fracture surface 16a of the protective film 16 faces the communication portion 13, even when the protective film 16 is broken, even if the protective film 16 remains on the fracture surface 16a so as to protrude, the reservoir portion 31. The remaining protective film 16 does not peel off due to the flow of ink from the nozzles, and clogging of the nozzle openings 21 can be prevented.

  The inner surface of the penetrating part 51 is formed as an inclined surface so that the angle between the inner surface of the penetrating part 51 and the surface of the elastic film 50 on the flow path forming substrate 10 side is an acute angle. The inclined surface of the penetrating portion 51 is provided so as to be inclined in a direction in which the flow path forming substrate 10 side protrudes into the penetrating portion 51 and becomes sharp. In this way, the inner surface of the penetrating portion 51 is formed into an inclined surface that is inclined so that the communicating portion 13 side protrudes from the reservoir portion 31 side to the penetrating portion 51, so that the protection on the isolation layer is performed in detail by a manufacturing method described later. The film 16 can be removed well and reliably together with the release layer.

  As shown in FIGS. 1 and 2, a nozzle opening 21 communicating with the vicinity of the end portion of each pressure generating chamber 12 opposite to the ink supply path 14 is formed on the opening surface side of the flow path forming substrate 10. The provided nozzle plate 20 is fixed by an adhesive, a heat welding 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, an elastic film 50 made of silicon dioxide and having a thickness of, for example, about 1.0 μm is formed on the side opposite to the opening surface of the flow path forming substrate 10. The insulating film 55 made of zirconium oxide (ZrO ₂ ) or the like and having a thickness of, for example, about 0.4 μm is laminated. On the insulator film 55, the 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 are formed. For example, the piezoelectric layer 300 is formed by laminating 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 by a process described later. 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, the insulator film 55, and the lower electrode film 60 function as a diaphragm. However, without providing the insulator film 55, the elastic film 50 and the lower electrode film 60 are used as the diaphragm. Also good.

  In addition, a lead electrode 90 composed of an isolation layer 190 composed of 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.

  Further, as will be described in detail later, an isolation layer 190 discontinuous from the lead electrode 90 and the lower electrode film 60 also exists on the diaphragm in the region corresponding to the peripheral edge of the opening of the communication portion 13, that is, on the elastic film 50. is doing.

  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. 4 to 10 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. 4A, a flow path forming substrate wafer 110, which is a silicon wafer, is thermally oxidized in a diffusion furnace at about 1100 ° C. to form a silicon dioxide film 57 constituting the elastic film 50 on the surface thereof. To do. 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. 4B, the through-hole 51 is formed in a region of the elastic film 50 (silicon dioxide film 57) opposite to the region where the communication portion 13 of the flow path forming substrate wafer 110 is formed. After that, a recess 52 is formed in a region exposed by the through portion 51 of the flow path forming substrate wafer 110.

  The through portion 51 can be formed by wet etching or dry etching of the elastic film 50. In the present embodiment, the penetrating portion 51 is formed by ion milling the silicon dioxide film 57. The through portion 51 formed by such a method is formed with an inclined surface whose inner surface is inclined with respect to the surface of the flow path forming substrate wafer 110.

  In this embodiment, the recess 52 can be formed by performing wet etching or dry etching on the flow path forming substrate wafer 110 using the elastic film 50 provided with the penetrating portion 51 as a mask. In this embodiment, the recess 52 is formed by ion milling the flow path forming substrate wafer 110 using the elastic film 50 as a mask. That is, in this embodiment, the penetration part 51 and the recessed part 52 of the elastic membrane 50 were formed simultaneously by ion milling. The inner surface of the recess 52 formed in this way is formed continuously with the inclined inner surface of the penetrating portion 51 in a planar shape.

  In this embodiment, the recess 52 is formed by ion milling. However, the present invention is not particularly limited thereto. For example, the recess 52 may be formed by wet etching the flow path forming substrate wafer 110. Then, the recess 52 may be formed by performing other dry etching such as reactive dry etching (RIE) on the flow path forming substrate wafer 110. In the case where the penetration part 51 is formed by reactive ion etching (RIE) of the elastic film 50, the recess 52 is formed by reactive ion etching of the flow path forming substrate wafer 110 by changing the gas. can do. Of course, the penetrating part 51 and the recessed part 52 can be formed by combining any of the etching methods described above.

  Next, as shown in FIG. 4C, the insulating film 53 is formed on the surface of the recess 52 by thermally oxidizing the flow path forming substrate wafer 110 and the elastic film 50. The insulating film 53 thus formed by thermal oxidation is a relatively thin film and is formed integrally with the elastic film 50. Further, since the insulating film 53 is formed over the surface of the flow path forming substrate wafer 110 exposed by the penetrating part 51, the communication part 13 is formed over the surface of the recess 52 in the insulating film 53. Protruding into the region.

  Next, as illustrated in FIG. 4D, the isolation layer 190 is formed on the insulating film 53. As a result, a protruding portion 191 that protrudes toward the communication portion 13 is formed in a region where the communication portion 13 is formed between the insulating film 53 and the isolation layer 190. Although the isolation layer 190 will be described in detail later, when the communication portion 13 is formed by wet-etching the flow path forming substrate wafer 110, the etching solution passes through the through portion 51 to the reservoir forming substrate wafer 130 side. This is to reinforce the insulating film 53 that prevents it from flowing out. For this reason, the material of the isolation layer 190 is not particularly limited. For example, platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium (Os), gold ( Examples thereof include noble metals such as Au) and silver (Ag), metal materials such as nickel (Ni), chromium (Cr), and nickel chromium (NiCr), and resin materials. Note that, as the isolation layer 190, a metal material having excellent etching resistance such as noble metal, nickel, chromium, nickel chrome, etc. is used, so that the etchant for wet etching the flow path forming substrate wafer 110 is used for the reservoir forming substrate. It is possible to more reliably prevent the wafer 130 from flowing out.

Next, as shown in FIG. 4E, an insulator film 55 made of zirconium oxide is formed on the elastic film 50 (silicon dioxide film 57), and the insulator film 55 is patterned into a predetermined shape. Specifically, after a zirconium (Zr) layer is formed on the elastic film 50 (silicon dioxide film 57) by, for example, a sputtering method, the zirconium layer is thermally oxidized in a diffusion furnace at 500 to 1200 ° C., for example. Thus, the insulator film 55 made of zirconium oxide (ZrO ₂ ) is formed. In addition, by performing wet etching or dry etching on the insulator film 55, an opening 56 having an opening area larger than that of the through part 51 is formed in a region where the through part 51 of the elastic film 50 is formed.

  Next, as shown in FIG. 5A, for example, platinum and iridium are stacked on the flow path forming substrate wafer 110 (including the insulator film 55, the elastic film 50, and the insulating film 53). After forming the lower electrode film 60, the lower electrode film 60 is patterned into a predetermined shape. Next, as shown in FIG. 5B, a piezoelectric layer 70 made of, for example, lead zirconate titanate (PZT) or the like, and an upper electrode film 80 made of, for example, iridium, are connected 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 material is dissolved and dispersed in a solvent 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. 5C, lead electrodes 90 are 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 isolation 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 isolation layer 190, and the metal layer 92 and the adhesion layer 91 are patterned for each piezoelectric element 300 through the mask pattern. 90 is formed.

  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. 6A, 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 several hundred μm, and the rigidity of the flow path forming substrate wafer 110 is significantly improved by bonding the reservoir forming substrate wafer 130. It will be.

  Next, as shown in FIG. 6B, the flow path forming substrate wafer 110 is thinned to a predetermined thickness. Next, as shown in FIG. 6C, a mask film 54 is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, as shown in FIG. 7A, 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 flow path forming substrate wafer 110 is etched with an etchant such as an aqueous solution of potassium hydroxide (KOH) until the elastic film 50 is exposed, whereby the pressure generating chamber 12, the communication portion 13, the ink The supply path 14 and the communication path 15 are formed simultaneously. In the present embodiment, the communication portion 13 is formed such that the opening edge on the diaphragm (elastic film 50) side is located outside the opening edge of the penetrating portion 51. That is, the communication part 13 is formed such that the opening on the diaphragm side is larger than the through part 51.

  Further, when the liquid flow path such as the pressure generation chamber 12 is formed in this way, the through portion 51 is sealed with the insulating film 53 and the isolation layer 190, so that the reservoir forming substrate wafer is interposed through the through portion 51. Etching liquid does not flow into the 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.

  Furthermore, in this embodiment, since the penetrating portion 51 is sealed with the insulating film 53 having excellent etching resistance and the isolation layer 190, the insulating layer 190 is insulated even if a material having low etching resistance is used. The film 53 can reliably prevent the etching solution from flowing into the reservoir forming substrate wafer 130 side. For this reason, the material of the isolation layer 190 is not limited, and a low-cost material can be used, so that the manufacturing cost can be reduced. In addition, the isolation layer 190 has a role of reinforcing the insulating film 53 formed of a thin film, and can reliably prevent the insulating film 53 having excellent etching resistance from being broken by the pressure of the etching solution.

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 liquid flow path such as the pressure generation chamber 12 is formed on the flow path forming substrate wafer 110 in this way, the protruding portion 191 that protrudes toward the communicating portion 13 side of the insulating layer 53 and the isolation layer 190 is exposed.

  Next, as shown in FIGS. 7B and 9A, the insulating film 53 exposed in the communicating portion 13 is removed. That is, by removing the insulating film 53 of the protrusion 191, the protrusion 191 is formed only by the isolation layer 190. A method for removing the insulating film 53 is not particularly limited, and examples thereof include wet etching and dry etching. In this embodiment, the insulating film 53 is removed by dry etching.

  Next, the mask film 54 on the surface of the flow path forming substrate wafer 110 is removed, and as shown in FIG. 8A, for example, from a material having liquid resistance (ink resistance) such as oxide or nitride. A protective film 16 is formed by a CVD method or the like.

  At this time, as shown in FIG. 9B, since the protruding portion 191 of the isolation layer 190 is exposed at the communicating portion 13, the protective film 16 is provided on one side of the elastic film 50 on the pressure generating chamber 12 side. To the exposed protruding portion 191 of the isolation layer 190. As a result, the protective film 16 formed on the surface of the elastic film 50 on the side of the communicating portion 13 is formed along the protruding portion 191 of the isolation layer 190 from the in-plane direction of the elastic film 50 on the peripheral edge side of the penetrating portion 51. A first bent portion 192 bent toward the communication portion 13 side and a second bent portion 193 where the protective film 16 toward the communication portion 13 side is bent toward the center side of the through portion 51 are provided.

  When the protective film 16 is formed in this way, since the through portion 51 is sealed by the isolation layer 190, the protective film 16 is formed on the outer surface of the reservoir forming substrate wafer 130 through the through portion 51. There is nothing. Accordingly, the protective circuit 16 is not formed on the surface of the reservoir forming substrate wafer 130 on which the connection wiring or the like is formed (the surface opposite to the surface bonded to the flow path forming substrate wafer 110), and the driving circuit 200 is formed. In addition, it is possible to prevent the occurrence of poor connection and the like, and it is not necessary to remove the extra protective film 16, thereby simplifying the manufacturing process and reducing the manufacturing cost.

  Next, as shown in FIG. 8B, 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 having a greater adhesion with the protective film 16 than with the adhesion between the protective film 16 and the isolation 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 isolation layer 190 starts to peel off due to the stress of the release layer 17. . Then, as shown in FIG. 10A, the peeling layer 17 is removed by wet etching, so that the protective film 16 on the isolation layer 190 is completely removed together with the peeling layer 17. In the present embodiment, a protrusion 191 is provided on the isolation layer 190, and the protective film 16 is formed over the protrusion 191, so that the protective film 16 is provided within the surface of the elastic film 50 in the vicinity of the peripheral edge of the penetrating part 51. The first bent portion 192 that is bent toward the communicating portion 13 from the direction and the second bent portion 193 that is bent toward the center of the penetrating portion 51 are provided for the protection film 16 toward the communicating portion 13 side. When the protective film 16 on the layer 190 is removed together with the release layer 17, the protective film 16 can be broken at the bent region, that is, the first bent portion 192 in the present embodiment.

  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 the occurrence of residue or cracks protruding like a bowl, and the eyes of the nozzle opening 21 due to the residue that has peeled off. Clogging or the like can be prevented, yield can be improved, and reliability can be improved.

  Further, by breaking the protective film 16 in the bent region in this way, the fracture surface 16a is formed facing the communication portion 13 side. For this reason, even if a small residue like a ridge is generated, the residue protrudes toward the communicating portion 13 side, and thus it is difficult to peel off when the ink flows in, and the nozzle opening 21 can be more reliably prevented from being clogged. it can.

  Furthermore, in this embodiment, since the insulating film 53 on the protruding portion 191 is removed before the protective film 16 is formed, the protective film 16 formed on the isolation layer 190 can be easily removed. .

  In the present invention, the communication portion 13 is formed such that the opening edge on the diaphragm (elastic film 50) side is outside the opening edge of the through portion 51. And the opening edge part by the side of the flow-path formation board | substrate wafer 110 of the penetration part 51 is comprised only with a diaphragm (elastic film | membrane 50), ie, an oxide. In this embodiment, the opening edge part of the communication part 13 is comprised only by the elastic film 50 substantially. For this reason, when the protective film 16 formed on the inner surface of the communication portion 13 or the like is peeled off together with the release layer 17, the protective film 16 is well separated along the opening edge of the communication portion 13, and the isolation layer 190. Only the upper protective film 16 is securely peeled and removed. Therefore, almost no so-called peeling residue is generated, and occurrence of nozzle clogging or the like due to this peeling residue can be reliably prevented.

  Further, in order to peel off the protective film 16 on the isolation layer 190 in this way, the angle between the inner surface of the penetrating part 51 (the end surface of the elastic film 50) and the surface of the diaphragm (the surface of the elastic film 50) is An acute angle of about 10 to 90 ° is preferable (see FIG. 9A). Furthermore, it is preferable that the penetration part 51 is formed in the opening shape that a corner | angular part does not exist along the peripheral part. For example, when the penetrating portion 51 is formed in a substantially rectangular opening shape, it is preferable that all four corners have an R shape. As a result, the protective film 16 on the isolation layer 190 can be peeled off together with the peeling layer 17 in a better and reliable manner.

  In the present embodiment, an example in which the protective film 16 is broken at the first bent portion 192 when the protective film 16 on the isolation layer 190 is removed together with the peeling layer 17 is shown. However, the protective film 16 is peeled off. Depending on the removal conditions of the layer 17, the second bent portion 193 may be broken.

  After removing the protective film 16 on the isolation layer 190 in this way, as shown in FIG. 10B, the isolation layer 190 is removed by wet etching from the communication portion 13 side to open the through portion 51. . At this time, since the protective film 16 is not formed on the isolation layer 190, the protective film 16 does not interfere with the wet etching of the isolation layer 190.

  Therefore, the through layer 51 can be opened by removing the isolation layer 190 easily and reliably by wet etching. 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 side of the isolation layer 190, the isolation layer 190 can be etched well and the isolation layer 190 can be reliably removed.

  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.

(Other embodiments)
The first embodiment of the present invention has been described above, but the basic configuration of the present invention is not limited to the above-described embodiment. For example, in Embodiment 1 described above, a metal material or a resin material is exemplified as the isolation layer 190, but the invention is not particularly limited thereto. For example, the adhesion layer 91 and the metal layer 92 that constitute the lead electrode 90 as the isolation layer 190 are used. It is also possible to use a layer that is the same layer as that of the lead electrode 90 and is discontinuous. In such a case, the process of separately forming the isolation layer 190 can be simplified. When the same adhesion layer 91 and metal layer 92 as the lead electrode 90 are used as the isolation layer 190, a part of the adhesion layer 91 on the side of the communication portion 13 is light-etched before the protective film 16 is formed. It is preferable to do this. Thereby, the protective film 16 can be easily peeled from the isolation layer 190.

  In Embodiment 1 described above, the insulating film 55 and the piezoelectric element 300 are formed after the isolation layer 190 is formed. However, the isolation layer 190 uses the reservoir forming substrate wafer 130 for the flow path forming substrate. As long as it is before bonding to the wafer 110, it may be formed at any timing.

  Furthermore, in the first embodiment described above, one recess 52 is formed across the through-hole 51 on the surface exposed by the through-hole 51 of the flow path forming substrate wafer 110. However, the present invention is particularly limited to this. For example, the concave portion may be provided in the penetrating portion 51 in, for example, a V shape. Further, the shape of the recess is not limited to the first embodiment described above, and the inner surface of the recess may be formed perpendicular to the surface of the flow path forming substrate wafer 110.

  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 manufacturing color filters such as liquid crystal displays, organic EL displays, and FED (field emission light emitting displays). ) And the like, electrode material ejection heads used for electrode formation, bio-organic matter ejection heads used for biochip production, and the like.

FIG. 2 is an exploded perspective view of a recording head according to Embodiment 1 of the invention. 2A and 2B are a plan view and a cross-sectional view of the recording head according to Embodiment 1 of the invention. FIG. 3 is an enlarged cross-sectional view of a main part of the recording head according to Embodiment 1 of the invention. FIG. 6 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment of the invention. FIG. 6 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment of the invention. FIG. 6 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment of the invention. FIG. 6 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment of the invention. FIG. 6 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment of the invention. FIG. 5 is an enlarged cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment of the invention. FIG. 5 is an enlarged cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment of the invention.

Explanation of symbols

  10 flow path forming substrate, 12 pressure generating chamber, 16 protective film, 16a fracture surface, 20 nozzle plate, 21 nozzle opening, 30 reservoir forming substrate, 31 reservoir portion, 32 piezoelectric element holding portion, 35 adhesive, 40 compliance substrate, 50 elastic film, 51 penetrating part, 52 recessed part, 53 insulating film, 55 insulating film, 60 lower electrode film, 70 piezoelectric layer, 80 upper electrode film, 90 lead electrode, 91 adhesion layer, 92 metal layer, 100 reservoir, DESCRIPTION OF SYMBOLS 110 Flow path formation substrate wafer, 130 Reservoir formation substrate wafer, 190 Isolation layer, 191 Protrusion part, 192 1st bending part, 193 2nd bending part, 200 Drive circuit, 210 Connection wiring, 300 Piezoelectric element

Claims (9)

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 is formed on one side of the substrate, a through-hole is formed in a region facing the communication portion of the diaphragm, and a region facing the through-portion of the flow path forming substrate is formed. Forming a recess;
Forming an insulating film having etching resistance when wet etching the flow path forming substrate so as to seal the penetrating portion on the one surface side of the flow path forming substrate;
By forming a piezoelectric element comprising a lower electrode, a piezoelectric layer and an upper electrode in a region corresponding to the pressure generating chamber on the diaphragm of the flow path forming substrate, and forming an isolation layer on the insulating film Forming a projecting portion in which the insulating film and the isolation layer project to the communicating portion side in a region where the communicating portion is formed;
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;
Forming the pressure generating chamber and the communicating portion by wet etching the flow path forming substrate from the other surface side, exposing the insulating film and exposing the protruding portion;
Removing the insulating film exposed on the side of the communicating portion and forming the protruding portion with the isolation layer;
Forming a protective film made of a liquid-resistant material on the pressure generating chamber of the flow path forming substrate, the inner surface of the communication portion, and the isolation layer;
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. The flow path forming substrate is made of a silicon single crystal substrate, and in the step of forming the diaphragm, the flow path forming substrate is thermally oxidized to have an elastic film made of silicon dioxide on the flow path forming substrate side. In the step of forming a diaphragm and forming the insulating film, the insulating film made of silicon dioxide provided integrally with the elastic film is formed by thermally oxidizing the flow path forming substrate. The method of manufacturing a liquid jet head according to claim 1. In the step of forming the protective film, by forming the protective film on the protruding portion, the protective film is bent in the vicinity of the peripheral portion of the penetrating portion from the diaphragm to the communicating portion side. In the step of forming the bent portion and the second bent portion bent toward the center side of the penetrating portion and peeling and removing the protective film on the isolation layer, the first bent portion of the protective film The method of manufacturing a liquid ejecting head according to claim 1, wherein the liquid ejecting head is broken at the portion or the second bent portion. The liquid ejecting head according to claim 1, wherein in the step of forming the concave portion, the concave portion is formed across a region facing the through portion of the flow path forming substrate. Production method. 5. The step of forming the concave portion is formed by anisotropically etching the flow path forming substrate using the diaphragm having the penetrating portion as a mask. 6. Manufacturing method of liquid jet head of 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. 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. 9. The method of manufacturing a liquid jet head according to claim 7, wherein titanium tungsten is used as a material of the release layer.

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