JP4821982B2 - Method for manufacturing liquid jet head - Google Patents

Description

The present invention relates to the production how a liquid ejecting head that ejects liquid, in particular, relates to the production how the ink jet recording head that discharges 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).

  Further, 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 doped layer (wiring layer of the present invention) on one surface of the flow path forming substrate. After that, after forming the pressure generating chamber and the communication part by anisotropic etching from the other side of the flow path forming substrate, the reservoir part is formed by communicating the reservoir part and the communication part through the boron dope layer. (For example, refer to Patent Document 3). 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 formation substrate is prevented from flowing out to the side and being etched.

  In addition, there is an ink jet recording head 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 generation chamber (for example, see Patent Document 2).

  However, when the protective film of Patent Document 3 is provided using the method of manufacturing an ink jet recording head of Patent Document 2, the protective film is formed after passing through the communication portion of the flow path forming substrate and the reservoir portion of the reservoir forming substrate. In this case, a protective film is also formed on the upper surface side of the reservoir forming substrate, and the protective film covers the wiring of the driving circuit provided on the reservoir forming substrate, resulting in poor connection between the driving circuit and the wiring. And a process for removing the protective film is required, resulting in an increase in manufacturing cost.

  Therefore, when the protective film is formed in a state where the wiring layer separates the communication portion of the flow path forming substrate and the reservoir portion of the reservoir forming substrate, the wiring layer that isolates the communication portion and the reservoir portion before penetrating the wiring layer It is necessary to peel off the upper protective film. At this time, if the distance between the end of the partition wall defining the pressure generating chamber and the end of the reservoir is large, the diaphragm is deformed and the protective film on the wiring layer cannot be peeled off. There is a problem that a residue in which the protective film protrudes like a bowl is generated between the reservoir portion and the communication portion. Such a protective film residue is easily peeled off, and the clogged protective film residue may cause nozzle clogging.

  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.

Japanese Patent Laying-Open No. 2005-186527 (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)

The present invention has been made in view of such circumstances, and an object thereof is to provide a foreign matter production how the liquid jet head capable of reliably preventing the discharge failure such as nozzle clogging due.

According to a first aspect of the present invention for solving the above-described problems, a liquid flow path having a pressure generation chamber that communicates with a nozzle opening for ejecting liquid and is partitioned by a plurality of partition walls, and communicates with the liquid flow path. having a lower electrode, a piezoelectric layer and an upper electrode via a communicating portion constituting a part of a reservoir serving as a common liquid chamber of the pressure generating chamber, a diaphragm on one side of the passage-forming substrate to be formed A step of forming a piezoelectric element and removing the diaphragm in the region serving as the communication portion to form a penetrating portion; and forming a lead electrode drawn from the piezoelectric element and comprising the same layer as the lead electrode. A step of sealing the through-portion with a wiring layer discontinuous from the lead electrode, and a reservoir forming substrate in which a reservoir portion that communicates with the communicating portion and forms a part of the reservoir is formed as the flow path forming substrate To the one side of the A step, and the liquid flow passages divided by a plurality of partition walls and wet etching to the diaphragm and the wiring layer using the flow path forming substrate from the other side is exposed, and the communicating portion, the said partition wall A step of forming the flow path formation so that a distance between the end of the reservoir and the end of the surface where the partition wall is in contact with the diaphragm is 5 to 200 μm; A protective film made of a material having liquid resistance is formed on the inner surface of the liquid flow path and the communication portion formed on the substrate, and peeling is made of a material having etching selectivity with respect to the protective film on the protective film. Forming a layer; removing the release layer by wet etching; and simultaneously removing the protective film on the wiring layer; and wet etching from the side of the communicating portion. In the method of manufacturing a liquid jet head characterized by including the step of removing the wire layer communicates with said communicating portion and the reservoir portion to form said reservoir, a.
In the first aspect, the distance between the end of the partition wall on the reservoir side and the end of the surface where the partition wall is in contact with the diaphragm is 200 μm or less, so that the diaphragm vibrates. The amount of deformation can be reduced by restraining the plate, and it is possible to prevent the residue of the protective film from being generated when the protective film is removed. In addition, the flow path forming substrate and the reservoir forming substrate are formed by setting the distance between the end portion of the partition wall on the reservoir portion side and the end portion of the surface where the partition wall is in contact with the diaphragm to 5 μm or more. It is possible to prevent the partition wall from projecting toward the reservoir due to the positioning error when joining the two, and to prevent the protective film residue from being generated when the protective film is removed. Furthermore, a space between the liquid flow path and the communication portion (reservoir), specifically, a space formed only by the flow path forming substrate and extending in the width direction of the pressure generation chamber can be partitioned and reduced by the partition wall, and the liquid Since the opening on the reservoir side of the flow path can be brought close to the reservoir portion of the reservoir forming substrate, the outflow of liquid from the liquid flow path can be diffused, and interference between liquids flowing out from the adjacent liquid flow paths can be reduced. The occurrence of crosstalk can be prevented.

According to a second aspect of the present invention, in the step of forming the liquid flow path, the pressure generating chamber and a liquid having a cross-sectional area smaller than a cross-sectional area in the width direction of the pressure generating chamber communicated with the pressure generating chamber. The liquid flow path comprising a supply path and a communication path communicating with the liquid supply path and having a cross-sectional area larger than the cross-sectional area in the width direction of the liquid supply path is partitioned and provided by the plurality of partition walls. The method of manufacturing a liquid jet head according to claim 1.
In the second aspect, the distance between the reservoir portion side end of the partition wall and the reservoir portion can be set to a desired distance without changing the dimensions of the pressure generation chamber, the liquid supply path, and the communication portion. It is possible to prevent the liquid discharge characteristics from deteriorating.

According to a third aspect of the present invention, in the method of manufacturing a liquid jet head according to the first or second aspect, an oxide or a nitride is used as a material for the protective film.
In the third aspect, it is possible to reliably prevent the flow path forming substrate from being eroded by the liquid and to form the protective film with a desired thickness and high accuracy.

According to a fourth aspect of the present invention, there is provided the liquid jet head manufacturing method according to the third aspect, wherein tantalum oxide is used as the material of the protective film.
In the fourth aspect, it is possible to reliably prevent the flow path forming substrate from being eroded by the liquid and to form the protective film with a desired thickness with high accuracy.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the adhesive force between the release layer and the protective film is greater than the adhesive force between the protective film and the wiring layer. The method is for manufacturing a liquid jet head.
In the fifth aspect, since the release layer and the protective film are in good contact with each other, the protective film on the wiring layer can be further easily and reliably removed together with the release layer.

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, the internal stress of the release layer is a compressive stress.
In the sixth aspect, since the protective film on the wiring layer is substantially peeled by the internal stress of the peeling layer, the protective layer can be selectively removed more reliably when the peeling layer is removed.

According to a seventh aspect of the present invention, in the method for manufacturing a liquid jet head according to any one of the first to sixth aspects, titanium tungsten is used as a material for the release layer.
In the seventh aspect, the protective film on the wiring layer is more reliably peeled by using the peeling layer having a predetermined stress.

According to an eighth aspect of the present invention, the method further includes the step of removing a portion of the wiring 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 eighth aspect, since the adhesion between the wiring layer and the protective film is weakened, the protective film on the wiring layer can be removed more reliably and reliably.

According to a ninth aspect of the present invention, the wiring layer comprises an adhesion layer and a metal layer formed on the adhesion layer, and the surface of the wiring 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 eighth aspect is provided.
In the ninth aspect, the adhesive force between the wiring layer and the protective film is more reliably weakened by light etching the wiring layer to remove a part of the metal layer in which the adhesion layer has diffused together with the adhesion layer. Further, the protective film on the wiring layer can be removed more satisfactorily and surely.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
1 is an exploded perspective view showing an ink jet recording head manufactured by a manufacturing method according to Embodiment 1 of the present invention, and FIG. 2 is a plan view and a cross-sectional view of FIG. As shown in the figure, the flow path forming substrate 10 is formed of a silicon single crystal substrate having a plane orientation (110) in this embodiment, and one surface thereof is previously formed of silicon dioxide by thermal oxidation to a thickness of 0.5 to 2 μm. The elastic film 50 is formed.

  In the flow path forming substrate 10, pressure generation chambers 12 partitioned by a plurality of partition walls 11 are arranged in parallel in the width direction by anisotropic etching from the other surface side. In addition, an ink supply path 14 and a communication path 15 that form a liquid flow path together with the pressure generation chamber 12 are partitioned by a partition wall 11 on one end side in the longitudinal direction of the pressure generation 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.

  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. It is formed with. 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 passage 15 is formed by extending the partition walls 11 on both sides in the width direction of the pressure generating chamber 12 to the communication portion 13 side to partition the space between the ink supply path 14 and the communication portion 13. Yes. That is, the flow path forming substrate 10 has an ink supply path 14 having a cross-sectional area smaller than the cross-sectional area of the pressure generating chamber 12 in the width direction, and communicates with the ink supply path 14 and disconnects the ink supply path 14 in the width direction. A liquid flow path including a communication passage 15 having a smaller cross-sectional area than the area is provided by being partitioned by a plurality of partition walls 11. The liquid flow path of the flow path forming substrate 10 will be described later in detail.

Here, a material having ink resistance, for example, pentoxide, is provided on the inner wall surface of the liquid flow path including the pressure generation chamber 12, the ink supply path 14, and the communication path 15 of the flow path forming substrate 10 and the communication portion 13. A protective film 16 made of tantalum oxide such as tantalum (Ta ₂ O ₅ ) is provided with a thickness of about 50 nm. The ink resistance referred to here is etching resistance against alkaline ink. In the present embodiment, the protective film 16 is also provided on the surface of the flow path forming substrate 10 on the side where the pressure generating chambers 12 and the like are open, that is, the bonding surface to which the nozzle plate 20 is bonded. Of course, since the ink is not substantially in contact with such a region, the protective film 16 may not be provided.

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.

  On the surface side of the flow path forming substrate 10 on which the protective film 16 is formed, a nozzle plate 20 in which nozzle openings 21 communicating with the vicinity of the end of each pressure generating chamber 12 on the side opposite to the ink supply path 14 are formed. However, it is fixed by an adhesive or a heat welding film. 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, as described above, the elastic film 50 having a thickness of, for example, about 1.0 μm is formed on the surface of the flow path forming substrate 10 opposite to the nozzle plate 20, and the elastic film 50 is formed on the elastic film 50. The insulator film 51 having a thickness of, for example, about 0.4 μm is formed. Further, on the insulator film 51, a lower electrode film 60 having a thickness of, for example, about 0.2 μm, a piezoelectric layer 70 having a thickness of, for example, about 1.0 μm, and a thickness of, for example, about 0 The upper electrode film 80 having a thickness of 0.05 μm is 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 the present embodiment, the lower electrode film 60 is used as a common electrode of the piezoelectric element 300 and the upper electrode film 80 is used as an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for convenience of a drive circuit and wiring.

  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. In addition, as will be described in detail later, the vibration electrode in the region corresponding to the peripheral edge of the opening of the communication portion 13, that is, the elastic film 50 and the insulator film 51 is also formed of the adhesion layer 91 and the metal layer 92, but the lead electrode 90. There is a discontinuous wiring layer 190.

  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 the present embodiment, the reservoir forming substrate 30 and the flow path forming substrate 10 are joined by an adhesive 35. The reservoir portion 31 of the reservoir forming substrate 30 communicates with the communication portion 13 through the elastic film 50 and the through portion 52 provided in the insulator film 51, and the reservoir 100 is formed by the reservoir portion 31 and the communication portion 13. Yes.

  Here, in the flow path forming substrate 10 provided with the communication portion 13, a liquid flow path including a pressure generation chamber 12 communicating with the communication portion 13, an ink supply path 14, and a communication path 15 is defined by the partition wall 11. Has been. That is, the liquid flow path including the pressure generation chamber 12, the ink supply path 14, and the communication path 15 is provided independently for each pressure generation chamber 12, and an individual flow between each pressure generation chamber 12 and the reservoir 100. Constitutes the road.

  Specifically, the partition wall 11 that defines the liquid flow path including the pressure generation chamber 12, the ink supply path 14, and the communication path 15 of the flow path forming substrate 10 is a portion of the joint portion of the flow path forming substrate 10 with the reservoir forming substrate 30. It extends to the vicinity of the end on the reservoir 31 side. By providing the communication path 15 in this way, when ink is ejected, ink flowing out from the adjacent ink supply path 14 toward the reservoir 100 does not interfere with each other, and the occurrence of crosstalk can be prevented. Therefore, stable ink ejection characteristics can be obtained regardless of whether or not ink droplets are ejected from the adjacent nozzle openings 21. In addition, the ink supply path 14 can be shortened without causing crosstalk, and the high-speed driving of the head can be realized by substantially improving the attenuation characteristic of the meniscus.

  Further, the end of the partition wall 11 that defines the liquid flow path on the reservoir section 31 side, and the end on the surface side where the partition wall 11 is in contact with the elastic film 50 that constitutes the vibration plate is the flow path forming substrate 10. And the reservoir forming substrate 30 are arranged in a region facing a joining portion where the reservoir forming substrate 30 is joined, that is, inside a through portion 52 that communicates the communicating portion 13 and the reservoir portion 31. For example, when the end of the partition wall 11 on the surface side in contact with the elastic film 50 on the reservoir portion 31 side protrudes to the reservoir 100 side, the communication portion 13 and the reservoir portion 31 are isolated from each other in the manufacturing process described later. This is because when the protective film 16 on the wiring layer is peeled off, a residue in which the protective film 16 remains in a bowl shape between the communication portion 13 and the reservoir portion 31 is generated. That is, when the end of the partition wall 11 in contact with the elastic film 50 is provided so as to protrude toward the reservoir section 31, the partition wall 11 restrains the wiring layer that separates the communication section 13 and the reservoir section 31. For this reason, when the protective film 16 on the wiring layer is peeled, deformation of the wiring layer is hindered, and the protective film 16 on the wiring layer cannot be completely peeled off.

  Further, when positioning and joining the flow path forming substrate 10 and the reservoir forming substrate 30 in the manufacturing process described in detail later, the positioning of the flow path forming substrate 10 and the reservoir forming substrate 30 has an error of about ± 3 μm. Therefore, when the distance S between the end of the flow path forming substrate 10 on the surface side of the partition wall 11 in contact with the elastic film 50 on the reservoir unit 31 side and the reservoir unit 31 is set to zero, the partition wall 11 becomes the reservoir. There is a risk of protruding to the portion 31 side. Therefore, the distance S between the end of the partition wall 11 of the flow path forming substrate 10 on the surface side in contact with the elastic film 50 on the reservoir portion 31 side and the reservoir portion 31 (through portion 52) is 5 μm or more. It is preferable to do this.

  Furthermore, the distance S between the end of the partition wall 11 defining the liquid flow path on the reservoir portion 31 side and the reservoir portion 31 is formed to be 200 μm or less. For example, if the distance S between the end of the partition wall 11 on the surface side in contact with the elastic film 50 on the reservoir portion 31 side and the reservoir portion 31 is too large, the communication portion will be described in detail in the manufacturing process described later. When the protective film 16 on the wiring layer separating the 13 and the reservoir portion 31 is peeled off, the restraint of the wiring layer by the partition wall 11 is reduced, so that the deformation amount of the wiring layer increases, and the protective film 16 on the wiring layer is increased. It is because it becomes impossible to peel completely.

  That is, the distance S between the end of the partition wall 11 that defines the liquid flow path and the end of the surface in contact with the elastic membrane 50 on the reservoir 31 side and the reservoir 31 is set to 5 μm to 200 μm. Generation of residues of the protective film 16 can be reduced during the process. And the residue of such a protective film 16 peels off, and discharge failure, such as clogging of the nozzle opening 21 by the residue of the protective film 16 which peeled off, can be prevented.

  In addition, ink is supplied by setting the distance between the end of the partition wall 11 defining the liquid flow path 11 on the surface side in contact with the elastic film 50 on the reservoir 31 side and the reservoir 31 to 5 μm to 200 μm. A space between the path 14 and the communication portion 13 (reservoir 100), specifically, a space configured only by the flow path forming substrate 10 and extending in the width direction of the pressure generating chamber 12 can be partitioned and reduced by the partition wall 11, In addition, since the opening on the reservoir 100 side of the partition wall 11, that is, the opening on the reservoir 100 side of the communication path 15 can be brought close to the reservoir portion 31 of the reservoir forming substrate 30, the outflow of ink from the communication path 15 is diffused, Interference between inks flowing out from adjacent communication paths 15 can be reduced, and occurrence of crosstalk can be prevented.

  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, a silicon single crystal substrate which is the same material as the flow path forming substrate 10 is used.

  A connection wiring 200 formed in a predetermined pattern is provided on the reservoir forming substrate 30, and a drive circuit 210 for driving the piezoelectric element 300 is mounted on the connection wiring 200. As the drive circuit 210, for example, a circuit board, a semiconductor integrated circuit (IC), or the like can be used. Then, the leading end portion of each lead electrode 90 drawn from each piezoelectric element 300 to the outside of the piezoelectric element holding portion 32 and the drive circuit 210 are electrically connected via the drive wiring 220.

  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 about several μm), and the sealing film 41 seals one surface of the reservoir unit 31. Has been. The fixing plate 42 is formed of a hard material such as metal (for example, stainless steel (SUS) having a thickness of about several tens of 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, after taking ink from an external ink supply means (not shown) and filling the interior from the reservoir 100 to the nozzle opening 21, according to the recording signal from the drive circuit 210, 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.

  First, as shown in FIG. 3A, a channel forming substrate wafer 110 which is a silicon wafer is thermally oxidized in a diffusion furnace at about 1100 ° C., and a silicon dioxide film 53 constituting an elastic film 50 is formed 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. 3B, an insulator film 51 made of zirconium oxide is formed on the elastic film 50 (silicon dioxide film 53). Specifically, after forming a zirconium (Zr) layer on the elastic film 50 (silicon dioxide film 53) by, for example, sputtering, the zirconium layer is thermally oxidized in a diffusion furnace at 500 to 1200 ° C., for example. Thus, the insulator film 51 made of zirconium oxide (ZrO ₂ ) is formed.

  Next, as shown in FIG. 3C, for example, after the lower electrode film 60 is formed by laminating platinum (Pt) and iridium (Ir) on the insulator film 51, the lower electrode film 60 is Pattern into a predetermined shape. Next, as shown in FIG. 3 (d), a piezoelectric layer 70 made of, for example, lead zirconate titanate (PZT) and an upper electrode film 80 made of, for example, iridium are connected to a 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. Further, after the piezoelectric element 300 is formed, the insulator film 51 and the elastic film 50 are patterned, and the insulator film 51 and the elastic film 50 are elastically formed in a region where a communication portion (not shown) of the flow path forming substrate wafer 110 is formed. A penetrating portion 52 that penetrates the film 50 and exposes the surface of the flow path forming substrate wafer 110 is formed.

As a material of the piezoelectric layer 70 constituting the piezoelectric element 300, for example, a ferroelectric piezoelectric material such as lead zirconate titanate (PZT), niobium, nickel, magnesium, bismuth, yttrium, or the like is used. 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 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.

  Next, as shown in FIG. 4A, a 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 52, and the through portion 52 is sealed by the wiring layer 190.

  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), aluminum (Al), and copper (Cu). In this case, 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 shown in FIG. 4B, the reservoir forming substrate wafer 130 is bonded onto the flow path forming substrate wafer 110 with an adhesive 35. Here, the reservoir forming substrate wafer 130 is preliminarily formed with a reservoir portion 31, a piezoelectric element holding portion 32, and the like, and the above-described connection wiring 200 is formed in advance on the reservoir forming substrate wafer 130. Yes. The reservoir forming substrate wafer 130 is a silicon wafer having a thickness of about 400 μm, for example.

  Next, as shown in FIG. 4C, 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. 5A, a mask film 54 made of, for example, silicon nitride (SiN) is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, as shown in FIG. 5B, the flow path forming substrate wafer 110 is anisotropically etched (wet etching) through the mask film 54, and the pressure generating chamber 12 is applied to the flow path forming substrate wafer 110. The liquid flow path including the ink supply path 14 and the communication path 15 and the communication portion 13 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 and the adhesion layer 91 are exposed, whereby the pressure generating chamber 12, the ink The liquid flow path including the supply path 14 and the communication path 15 and the communication portion 13 are formed simultaneously.

  At this time, the end of the partition wall 11 defining the liquid flow path of the flow path forming substrate wafer 110 on the surface side in contact with the elastic film 50 on the reservoir section 31 side is formed between the flow path forming substrate wafer 110 and the reservoir. It is formed so as to be in the region facing the bonding portion where the substrate wafer 130 is bonded, that is, inside the through portion 52 that connects the communication portion 13 and the reservoir portion 31. This is because, for example, when the end of the partition wall 11 on the surface side in contact with the elastic film 50 on the reservoir portion 31 protrudes toward the reservoir 100, the wiring that separates the communication portion 13 and the reservoir portion 31 in a later step. This is because when the protective film 16 on the layer 190 is peeled off, a residue in which the protective film 16 remains in a bowl shape between the communication portion 13 and the reservoir portion 31 is generated. That is, when the end of the partition wall 11 on the surface side in contact with the elastic film 50 on the reservoir section 31 side is provided so as to protrude toward the reservoir section 31, the partition wall 11 isolates the communication section 13 and the reservoir section 31. Since the wiring layer 190 is constrained, when the protective film 16 on the wiring layer 190 is peeled, the deformation of the wiring layer 190 is inhibited, and the protective film 16 on the wiring layer 190 cannot be completely peeled off. It is.

  Further, when the flow path forming substrate wafer 110 and the reservoir forming substrate wafer 130 are positioned and bonded, the positioning of the flow path forming substrate wafer 110 and the reservoir forming substrate wafer 130 has an error of about ± 3 μm. Therefore, when the distance S between the end of the flow path forming substrate wafer 110 on the surface side of the partition wall 11 in contact with the elastic film 50 on the reservoir unit 31 side and the reservoir unit 31 is set to zero, the partition wall 11 May protrude to the reservoir 31 side. For this reason, the distance S between the end of the surface of the flow path forming substrate wafer 110 in contact with the elastic film 50 on the reservoir portion 31 side of the partition wall 11 and the reservoir portion 31 (through portion 52) is 5 μm. The above is preferable.

  Further, the partition wall 11 that defines the liquid flow path is formed so that the distance S between the end portion on the surface side in contact with the elastic film 50 on the reservoir portion 31 side and the reservoir portion 31 is 200 μm or less. This will be described in detail later. For example, if the distance S between the end of the partition wall 11 on the surface side in contact with the elastic film 50 on the reservoir portion 31 side and the reservoir portion 31 is too far apart, When the protective film 16 on the wiring layer 190 that separates the communication part 13 and the reservoir part 31 is peeled off, the restraint of the diaphragm (elastic film 50) by the partition wall 11 decreases, so that the deformation amount of the diaphragm increases. This is because the protective film 16 on the wiring layer 190 cannot be completely removed. That is, by setting the distance S between the end of the partition wall 11 defining the liquid flow path 11 on the surface side in contact with the elastic film 50 on the reservoir portion 31 side and the reservoir portion 31 to 5 μm to 200 μm, In this process, when the protective film 16 on the wiring layer 190 is peeled off, the diaphragm (elastic film 50) is restrained by the partition wall 11, and the deformation amount of the diaphragm is suppressed, and a residue of the protective film 16 is generated. Can be reduced. And the residue of such a protective film 16 peels off, and discharge failure, such as clogging of the nozzle opening 21 by the residue of the protective film 16 which peeled off, can be prevented.

  Further, the distance S between the end of the partition wall 11 that defines the liquid flow path and the end of the surface in contact with the elastic film 50 on the reservoir 31 side, and the reservoir 31 is set to 5 μm to 200 μm. A space between the supply path 14 and the communication portion 13 (reservoir 100), specifically, a space constituted only by the flow path forming substrate wafer 110 and extending in the width direction of the pressure generating chamber 12 is partitioned by the partition wall 11. Since the opening on the reservoir 100 side of the partition wall 11, that is, the opening on the reservoir 100 side of the communication path 15 can be made closer to the reservoir portion 31 of the reservoir forming substrate wafer 130, the ink flows out from the communication path 15. And the interference between the inks flowing out from the adjacent communication passages 15 can be reduced, and the occurrence of crosstalk can be prevented.

  When forming the liquid flow path on the flow path forming substrate wafer 110, the surface of the reservoir forming substrate wafer 130 opposite to the flow path forming substrate wafer 110 side is made of a material having alkali resistance, such as PPS. It may be further sealed with a sealing film made of (polyphenylene sulfide), PPTA (polyparaphenylene terephthalamide) or the like. Thereby, defects such as disconnection of wiring provided on the surface of the reservoir forming substrate wafer 130 can be more reliably prevented.

  Next, as shown in FIG. 6A, a part of the wiring layer 190 in the penetrating part 52 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. 6B, in the liquid flow path and in the communication portion 13, that is, the pressure generation chamber 12 and the ink supply path 14. The protective film 16 is formed on the inner surface of the liquid flow path including the communication passage 15 and the communication portion 13. As described above, the protective film 16 is made of, for example, a material having liquid resistance (ink resistance) such as oxide or nitride, and in the present embodiment, is made of tantalum pentoxide. Moreover, the formation method of the protective film 16 is not particularly limited, but can be formed by, for example, a CVD method.

  At this time, since the penetrating portion 52 is sealed by the wiring layer 190, the protective film 16 is not formed on the outer surface or the like of the reservoir forming substrate wafer 130 via the penetrating portion 52. Therefore, the protective film 16 is formed on the surface of the reservoir forming substrate wafer 130 on which the connection wiring 200 and the like are formed, and it is possible to prevent the connection failure of the drive circuit 210 and the like from occurring. At the same time, the process of removing the extra protective film 16 is not required, and the manufacturing process can be simplified and the manufacturing cost can be reduced.

  Next, as shown in FIG. 6C, a release layer 17 made of a material having etching selectivity with respect to the protective film 16 is formed on the protective film 16 by, for example, a CVD method or the like. Here, the protective film 16 is a material having etching selectivity, which means that the protective film 16 is hardly etched by an etchant for wet etching the material and is not substantially etched. Moreover, it is preferable that the internal stress of the peeling layer 17 is a compressive stress, and it is particularly preferable that the release layer 17 has a compressive stress of 80 MPa or more. Further, it is preferable that the release layer 17 is 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. For example, in this embodiment, a titanium tungsten compound (TiW) that satisfies the above conditions is used as the material of the release layer 17.

Next, as shown in FIG. 7A, the peeling layer 17 is completely removed by wet etching, and at the same time, the protective film 16 on the wiring layer 190 is selectively removed. Here, the adhesive force between the protective film 16 and the metal layer 92 made of gold (Au) is weaker than the adhesive force between the protective film 16 and the elastic film 50 made of silicon dioxide (SiO ₂ ). Since the stress is a compressive stress, by forming the release layer 17 on the protection film 16, the protection film 16 is peeled from the wiring layer 190 to some extent by the internal stress of the release layer 17. Then, by removing the release layer 17 by wet etching, the protective film 16 on the wiring layer 190 is also selectively removed at the same time.

  At this time, as described above, the distance S between the end of the partition wall 11 that defines the liquid flow path and the end of the side in contact with the elastic film 50 on the reservoir 31 side and the reservoir 31 is 5 to 200 μm. Therefore, the elastic film 50, the insulator film 55, and the lower electrode film 60, which are vibration plates, are appropriately displaced, and only the protective film 16 on the wiring layer 190 can be selectively removed. Thereby, it is possible to prevent a residue in which the protective film 16 remains in a bowl shape, and to prevent the residue from peeling off and causing an ink discharge defect due to clogging of the nozzle opening 21.

  That is, as shown in FIGS. 8A and 9A, the distance S between the end portion of the partition wall 11 on the surface side in contact with the elastic film 50 on the reservoir portion 31 side and the reservoir portion 31 is increased. When the protective film 16 on the wiring layer 190 is peeled off, the restraint of the wiring layer 190 by the partition wall 11 is reduced, so that the deformation amount of the diaphragm (elastic film 50) increases, and the protection on the wiring layer 190 is increased. The film 16 cannot be completely peeled off, and a large residue 16a in which the protective film 16 remains in a bowl shape is generated between the communication portion 13 and the reservoir portion 31. Such a residue 16a of the protective film 16 is peeled off, thereby causing a discharge failure such as clogging of the nozzle opening 21.

  On the other hand, in the case where the distance S between the end of the partition wall 11 that defines the liquid flow path and the end of the surface in contact with the elastic membrane 50 on the reservoir 31 side and the reservoir 31 is 5 to 200 μm. As shown in FIGS. 8B and 9B, since the partition wall 11 restrains the diaphragm (elastic film 50), a large residue 16a is generated in the protective film 16 while suppressing the deformation amount of the diaphragm. Can be prevented. Then, it is possible to prevent ejection defects such as clogging of the nozzle openings 21 due to the large residue 16a of the protective film 16 as shown in FIGS. 8A and 9A.

  FIG. 8 is an enlarged cross-sectional view when the distance S is changed, and FIG. 9 is an image when the distance S is changed.

  After removing the protective film 16 on the wiring layer 190 in this way, as shown in FIG. 7B, the wiring layer 190 (metal layer 92) is removed by wet etching from the communication portion 13 side and penetrated. The part 52 is opened. 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 52.

  Further, when the reservoir 100 is formed by such a method, the protective film 16 is not formed on the surface of the wiring layer 190 exposed in the reservoir 100. For this reason, although there is a possibility that the wiring layer 190 is eroded by the ink, the amount is very small, and there is no problem at all as the life of the head. Although not shown, since the silicon dioxide film is formed on the inner surface of the reservoir portion 31 by thermally oxidizing the reservoir forming substrate wafer 130, the protective film 16 may not be provided.

  Thereafter, the drive circuit 210 is mounted on the connection wiring 200 formed on the reservoir forming substrate wafer 130, and the drive circuit 210 and the lead electrode 90 are connected by the drive wiring 220 (see FIG. 2). Then, unnecessary portions of the outer peripheral edge 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.

Example 1
According to the manufacturing method similar to that of the first embodiment described above, two rows of pressure generating chambers and piezoelectric elements are provided on the flow path forming substrate, and a communication passage communicating with each row of pressure generating chambers is provided on one side of the row of pressure generating chambers. Two ink jet recording heads were provided. Further, in Example 1, the distance S between the end of the partition wall defining the liquid flow path of each ink jet recording head and the side of the reservoir in contact with the elastic film on the side of the reservoir is set to 33 μm. I made it.

(Example 2)
Similar to the first embodiment, two ink jet recording heads each having two rows of pressure generating chambers and piezoelectric elements are formed, and the elasticity of the partition wall 31 side of the partition wall defining the liquid flow path of each ink jet recording head. The distance S between the end of the surface in contact with the membrane and the reservoir was set to 192 μm.

(Comparative Example 1)
For comparison, two rows of pressure generating chambers and piezoelectric elements are provided on the flow path forming substrate by the same manufacturing method as in Embodiment 1 described above, and communicated with each row of pressure generating chambers on one side of the row of pressure generating chambers. Two ink jet recording heads provided with a communicating path were formed. In the first comparative example, the distance S between the end of the partition wall that defines the liquid flow path of each ink jet recording head and the surface of the partition that is in contact with the elastic film on the reservoir side is 242 μm. I made it.

(Comparative Example 2)
For comparison, two rows of pressure generating chambers and piezoelectric elements are provided on the flow path forming substrate by the same manufacturing method as in Embodiment 1 described above, and communicated with each row of pressure generating chambers on one side of the row of pressure generating chambers. Two ink jet recording heads provided with a communicating path were formed. Further, in Comparative Example 2, the distance S between the end of the partition wall defining the liquid flow path of each ink jet recording head and the surface of the partition in contact with the elastic film on the reservoir side is 271 μm. I made it.

(Test example)
The number of residues generated in the protective film of each of the two ink jet recording heads of Examples 1 and 2 and Comparative Examples 1 and 2 was measured. These results are shown in FIG. FIG. 10 is a graph showing the distance S and the number of protective film residues generated. Moreover, the A row | line | column and B row | line | column of the graph shown in FIG. 10 show the row | line | column of the pressure generation chamber arranged in parallel.

  From the results shown in FIG. 10, when the distance S between Examples 1 and 2 is set to 5 to 200 μm, in Comparative Examples 1 and 2 in which the distance S is increased compared to the case where no protective film residue is generated, It turns out that the residue of a protective film has generate | occur | produced. Moreover, it turned out that the generation | occurrence | production number of residue is increasing, so that the distance S leaves | separates from FIG.

  From the above results, the protective film can be formed by setting the distance S between the end of the partition wall defining the liquid flow path and the end of the surface in contact with the elastic membrane on the reservoir side to the reservoir portion to 5 to 200 μm. The occurrence of such residue can be reduced, and ink discharge defects such as clogging of the nozzle opening due to the residue peeling off can be prevented.

(Other embodiments)
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to embodiment mentioned above of course. For example, in the above-described embodiment, the wiring layer composed of the adhesion layer and the metal layer is illustrated, but the layer structure of the wiring layer is not particularly limited, and the wiring layer is formed only of the metal layer, for example. It may be formed of three or more layers.

  In Embodiment 1 described above, the pressure generation chamber 12, the ink supply path 14, and the communication path 15 are provided as the liquid flow paths. However, the liquid flow paths may be connected depending on the relationship between pressure and volume, crosstalk, and the like. Even when the passage 15 is not provided, the distance S between the end of the partition wall 11 on the surface side in contact with the elastic membrane 50 on the reservoir 31 side and the reservoir 31 is preferably 5 to 200 μm. .

  Furthermore, in the above-described embodiment, the ink jet recording head has been described as an example of the liquid ejecting head. However, the present invention is widely intended for 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. It is an expanded sectional view at the time of changing the distance S. It is an image when the distance S is changed. It is a graph which shows the result of a test example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 13 Communication part, 14 Ink supply path, 15 Communication path, 16 Protective film, 16a Residue, 20 Nozzle plate, 21 Nozzle opening, 30 Reservoir formation board, 31 Reservoir part, 40 Compliance Substrate, 50 elastic film, 51 insulator film, 52 penetrating 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 connection wiring, 210 drive circuit, 220 drive wiring, 300 piezoelectric element

Claims (9)

A liquid flow path having a pressure generation chamber that communicates with a nozzle opening that ejects liquid and is partitioned by a plurality of partition walls, and a part of a reservoir that communicates with the liquid flow path and serves as a common liquid chamber of the pressure generation chamber Forming a piezoelectric element having a lower electrode, a piezoelectric layer, and an upper electrode through a diaphragm on one surface side of the flow path forming substrate on which the communication portion is formed, and in the region serving as the communication portion Removing the diaphragm and forming a through portion;
Forming a lead electrode drawn out from the piezoelectric element and comprising the same layer as the lead electrode, but sealing the penetrating portion with a discontinuous wiring layer from the lead electrode;
Bonding a reservoir forming substrate formed with a reservoir portion that constitutes a part of the reservoir in communication with the communicating portion to the one surface side of the flow path forming substrate;
The liquid flow path partitioned by a plurality of partition walls by wet-etching the flow path forming substrate from the other surface side until the vibration plate and the wiring layer are exposed, and the communication section. Forming the distance between the reservoir portion and the end portion of the surface that is the side end portion of the partition wall in contact with the diaphragm; and
A protective film made of a material having liquid resistance is formed on the inner surface of the liquid flow path and the communication portion formed on the flow path forming substrate, and has an etching selectivity with respect to the protective film on the protective film. Forming a release layer made of a material;
Removing the release layer by wet etching and simultaneously removing the protective film on the wiring layer;
And a step of removing the wiring layer by wet etching from the side of the communication part to form the reservoir by connecting the reservoir part and the communication part. Method.   In the step of forming the liquid flow path, the pressure generation chamber, a liquid supply path communicating with the pressure generation chamber and having a cross-sectional area smaller than a cross-sectional area in the width direction of the pressure generation chamber, and the liquid supply path 2. The liquid jet according to claim 1, wherein the liquid flow path including a communication path that communicates and has a cross-sectional area larger than a cross-sectional area in the width direction of the liquid supply path is defined by a plurality of the partition walls. Manufacturing method of the head.   The method of manufacturing a liquid jet head according to claim 1, wherein an oxide or a nitride is used as a material of the protective film.   The method of manufacturing a liquid jet head according to claim 3, wherein tantalum oxide is used as a material of the protective film.   5. The method of manufacturing a liquid jet head according to claim 1, wherein an adhesion force between the peeling layer and the protective film is greater than an adhesion force between the protective film and the wiring layer.   The method for manufacturing a liquid jet head according to claim 1, wherein the internal stress of the release layer is a compressive stress.   The method for manufacturing a liquid jet head according to claim 1, wherein titanium tungsten is used as a material of the release layer.   8. The method according to claim 1, further comprising a step of removing a portion of the wiring layer exposed in the communication portion in a thickness direction before the step of forming the protective film. A method for manufacturing a liquid jet head.   The wiring 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 wiring layer is light-etched to at least remove the adhesion layer. The method of manufacturing a liquid jet head according to claim 8.

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