JP2014004725A - Method for manufacturing liquid discharge head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a double actuator type liquid discharge head by simpler machining and in a shorter manufacturing time.SOLUTION: A plurality of first grooves 14 are formed and second grooves 19 are formed in a first piezoelectric substrate 12. A plurality of third grooves 34 are formed in a second piezoelectric substrate 32. First electrodes 20 are formed on side faces and a bottom face of each of the first grooves 14. Second electrodes 21 are formed on side faces of the second grooves 19. A third electrode 25 is formed on a face 23 of the first piezoelectric substrate 12. A fourth electrode 39 is formed on a bottom face of each of the third grooves 34. A fifth electrode 41 is formed on a face 40 of the second piezoelectric substrate 32. Polarization of side walls and polarization of a bottom wall are performed in each of the first grooves 14, and polarization of a bottom wall of each of the third grooves 34 is performed. The second electrodes 21 and the third electrodes 25 are separated into at least two electrodes while the fourth electrode 39 is separated into at least two electrodes. The second piezoelectric substrate 32 is joined to the first piezoelectric substrate 12.

Description

  The present invention relates to a method for manufacturing a liquid discharge head that discharges liquid.

  2. Description of the Related Art Generally, a liquid discharge head that discharges liquid is mounted on an ink jet recording apparatus that records an image on a recording medium by discharging a liquid such as ink.

  As a mechanism for discharging a liquid by a liquid discharge head, a mechanism is known that includes a pressure chamber whose volume can be expanded and contracted, and applies a discharge force to the liquid in the pressure chamber by expanding and contracting the volume of the pressure chamber. The pressure chamber communicates with the discharge port, and the liquid to which the discharge force is applied is discharged from the discharge port.

  As one of liquid discharge heads having such a mechanism, a liquid discharge head called a Gould type has been proposed in which a pressure chamber is formed of a piezoelectric member having a cylindrical shape with a circular or rectangular cross section. In the Gould type liquid discharge head, the volume of the pressure chamber is expanded and contracted by uniformly deforming the wall of the pressure chamber containing the piezoelectric material in the radial direction of the pressure chamber. Since all the walls forming the pressure chamber are deformed to expand and contract the volume of the pressure chamber, the volume of the pressure chamber is relatively large, and a relatively large discharge force can be applied to the liquid.

  In order to obtain a higher resolution in the Gould type liquid discharge head, it is necessary to provide a plurality of discharge ports and pressure chambers corresponding to each discharge port at a higher density. A method for manufacturing a liquid discharge head capable of providing pressure chambers with higher density is disclosed in Patent Document 1.

  The manufacturing method disclosed in Patent Document 1 will be described.

  First, a plurality of grooves extending in the same direction are formed in each of the plurality of piezoelectric plates. Thereafter, a plurality of piezoelectric plates are stacked with the direction in which the grooves extend aligned. At this time, the opening of the groove is closed by the adjacent piezoelectric plate, and a pressure chamber is formed. The stacked piezoelectric plates are cut in a direction orthogonal to the direction in which the grooves extend to form a piezoelectric member. The pressure chamber penetrates the piezoelectric member, and the liquid flows in the pressure chamber from one opening of the pressure chamber toward the other opening.

  Thereafter, a groove is formed on one surface of the outer surface of the piezoelectric member having the opening of the pressure chamber. The groove is formed between adjacent pressure chambers, and each pressure chamber can be expanded and contracted independently. Then, the printed wiring board and the nozzle plate are joined to one surface of the piezoelectric member, and the supply path plate and the ink pool plate are joined to the other surface of the piezoelectric member, thereby completing the liquid ejection head.

  According to the manufacturing method disclosed in Patent Document 1, since the pressure chambers can be arranged in a matrix, the pressure chambers can be arranged at a relatively high density. Also, since it is easier to form grooves in the piezoelectric plate than in the case of forming holes in the piezoelectric member having a plate shape, it is said that the pressure chamber can be formed with relatively high accuracy according to this manufacturing method. Yes.

  Incidentally, in recent years, in order to reduce deformation of paper curl and cockling due to moisture contained in the ink, it has been required to further reduce the moisture content of the ink and to record characters and images using ink having a higher viscosity. It has been. Then, a liquid discharge head capable of applying a larger discharge force to the liquid so that ink having higher clay can be discharged has been studied.

  Patent Document 2 discloses a liquid discharge head (double actuator type liquid discharge head) including two piezoelectric elements arranged in a flow direction (hereinafter, simply referred to as a flow direction) of a liquid flowing in a pressure chamber.

  Specifically, the first piezoelectric element is a single-layer piezoelectric element in which electrodes are provided on both surfaces of one piezoelectric plate, and the first pressure located on the discharge port side in the pressure chamber. The wall of the chamber part is formed. The second piezoelectric element is a stacked piezoelectric element in which a plurality of piezoelectric plates and electrodes are alternately stacked, and has a through-hole penetrating in the stacking direction of the piezoelectric plates. The through hole forms a second pressure chamber portion located on the opposite side of the pressure chamber from the discharge port.

  In the double actuator type liquid discharge head, the first piezoelectric element is deformed while the second pressure chamber portion is contracted by the second piezoelectric element. By contracting the second pressure chamber portion, the liquid in the pressure chamber is unlikely to flow backward through the second pressure chamber portion. That is, the force applied to the liquid in the first pressure chamber portion due to the expansion / contraction of the volume of the first pressure chamber portion acts in a direction toward the discharge port. As a result, a larger discharge force is applied to the liquid.

  Further, the liquid is easily supplied to the pressure chamber by enlarging the second pressure chamber portion with the second piezoelectric element. As a result, the refill property is improved.

JP 2007-168319 A JP 2008-155537 A

  However, the manufacturing method disclosed in Patent Document 1 cannot manufacture a double actuator type liquid discharge head for the following reason.

  That is, in the double actuator type liquid discharge head, two piezoelectric elements are required in the flow direction. When the manufacturing method disclosed in Patent Document 1 is used, one opening side portion of the pressure chamber wall is a first piezoelectric element, and the other opening side portion is a second piezoelectric element. A double actuator type liquid discharge head is manufactured. Therefore, the dimensions of the pressure chamber in the flow direction must be relatively large.

  However, in the manufacturing method disclosed in Patent Document 1, in order to increase the dimension of the pressure chamber in the flow direction, the thickness of the piezoelectric member is increased to increase the groove formed on the surface having the opening of the pressure chamber. The depth must be deeper. When the depth of the groove is increased, the rigidity of the wall of the pressure chamber is lowered, and the wall of the pressure chamber is easily broken when the groove is formed.

  For this reason, the manufacturing method disclosed in Patent Document 1 cannot increase the size of the pressure chamber in the flow direction, and it is difficult to manufacture a double actuator type ejection head.

  Moreover, in the manufacturing method disclosed in Patent Document 2, a plurality of piezoelectric plates having through holes are stacked to produce a second piezoelectric element. That is, through holes must be formed in a plurality of piezoelectric plates, and relatively complicated processing has to be performed.

  Furthermore, in the manufacturing method disclosed in Patent Document 2, the multilayer piezoelectric element is manufactured after the process of manufacturing the single-layer piezoelectric element. For this reason, the manufacturing time required to complete the liquid discharge head is long.

  Therefore, an object of the present invention is to provide a method for manufacturing a double actuator type liquid discharge head with simpler processing and in a shorter manufacturing time.

  In order to achieve the above object, the present invention provides a plurality of individual liquid chambers that are partitioned by a wall of piezoelectric material and communicate with a discharge port for discharging liquid, and adjacent individual liquid chambers that are arranged around the individual liquid chambers. A liquid discharge device comprising: a recess that separates the walls of the individual liquid chamber; an inner electrode disposed on an inner surface of the individual liquid chamber; and a plurality of outer electrodes disposed on the outer surface of the individual liquid chamber and arranged in the depth direction of the individual liquid chamber. The present invention relates to a method for manufacturing a head. In this aspect, a preparation process for preparing the first and second piezoelectric substrates, a groove formation process, an electrode formation process, a polarization process, an electrode separation process, and a lamination process are included. In the groove forming step, a plurality of first grooves extending in parallel with each other are formed on the first surface A1 of the first piezoelectric substrate, and the second grooves extending in parallel with the first grooves are adjacent to each other. A plurality of third grooves formed between the first grooves and extending in parallel with each other are formed on the first surface B1 of the second piezoelectric substrate. In the electrode forming step, the first electrode is formed on the side surface and the bottom surface of the first groove, the second electrode is formed on the side surface of the second groove, and the first surface A1 of the first piezoelectric substrate Forms a third electrode on the second surface A2 on the opposite side, forms a fourth electrode on the bottom surface of the third groove, and is on the opposite side of the second piezoelectric substrate from the first surface B1. A fifth electrode is formed on the second surface B2. In the polarization step, a voltage is applied between the first electrode and the second and third electrodes to polarize the side wall of the first groove and the bottom wall, and the fourth electrode and the fifth electrode A voltage is applied between and the bottom wall of the third groove is polarized. In the electrode separation step, the plurality of second and third electrodes are separated into at least two in the direction in which the first groove extends, and the fourth electrode is separated into at least two in the direction in which the third groove extends. To do. In the stacking step, the first surface A1 of the first piezoelectric substrate, the second surface B2 of the second piezoelectric substrate, with the position of the first groove and the position of the third groove being matched, Join. The first groove is an individual liquid chamber, the second and third grooves are recesses, the first and fifth electrodes are inner electrodes, and the second, third, and fourth electrodes are outer electrodes. .

  According to the present invention, a double actuator type liquid discharge head can be manufactured with simpler processing and in a shorter manufacturing time.

FIG. 2 is a perspective view of a liquid discharge head unit manufactured using the first embodiment of the present invention. FIG. 2 is an exploded perspective view of the liquid discharge head unit shown in FIG. 1. The flowchart figure of the manufacturing method which concerns on the 1st Embodiment of this invention. The top view which shows an example of the 1st piezoelectric substrate in which the some groove | channel was formed. The perspective view for demonstrating the method of forming the 1st piezoelectric substrate shown by FIG. Sectional drawing for demonstrating the method to form the 1st, 2nd and 3rd electrode in a 1st piezoelectric substrate. The top view which shows an example of the 2nd piezoelectric substrate in which the some groove | channel was formed. The perspective view for demonstrating the method of forming the 2nd piezoelectric substrate shown by FIG. Sectional drawing for demonstrating the method of forming a 4th electrode in a 2nd piezoelectric substrate. FIG. 6 is a perspective view showing another example of the fourth piezoelectric substrate shown in FIG. 2. The perspective view for demonstrating the process of laminating | stacking a 1st, 2nd, 3rd and 4th piezoelectric substrate. FIG. 4 is a perspective view of a liquid discharge head in which lead-out wiring is formed. Sectional drawing for demonstrating the electrode patterning of a 1st end surface. E-E 'sectional drawing in FIG. FIG. 6 is a perspective view and a cross-sectional view of a liquid discharge head in which a lead wiring is formed. FIG. 4 is a perspective view and an enlarged front view of a liquid discharge head in which lead-out wiring from a first electrode is formed. H-H 'sectional drawing in FIG. FIG. 3 is an exploded perspective view showing a positional relationship between a wiring board and a liquid discharge head. I-I 'sectional drawing in FIG. The top view and sectional side view of the location corresponding to an individual liquid chamber of a back aperture plate. FIG. 3 is an exploded perspective view showing a positional relationship among a rear diaphragm plate, a liquid discharge head, and an orifice plate. The top view and side sectional drawing of the location corresponding to an individual liquid chamber of an orifice plate. The perspective view of the liquid discharge head to which the 1st, 2nd and 3rd flexible substrate was crimped | bonded. The cross-sectional enlarged view of the area | region J shown by FIG.11 (b). FIG. 3 is a perspective view illustrating an appearance of a liquid discharge head manufactured using the manufacturing method according to the embodiment. K-K 'sectional drawing in FIG.

  An example of a method for manufacturing a liquid discharge head according to the present invention and a liquid discharge head manufactured using the manufacturing method will be described with reference to the drawings.

(First embodiment)
First, a first embodiment of the present invention will be described. FIG. 1 is a perspective view of a liquid discharge head unit manufactured using the manufacturing method according to the present embodiment. FIG. 2 is an exploded perspective view of the liquid discharge head unit shown in FIG.

  As shown in FIGS. 1 and 2, the liquid discharge head unit 1 includes an orifice plate 2, a liquid discharge head 3, a rear throttle plate 4, and a common liquid chamber 5 that are stacked in this order.

  The liquid discharge head 3 includes an individual liquid chamber 6 and a recess 7 (also referred to as an air chamber 7) formed around the individual liquid chamber. The common liquid chamber 5 communicates with the individual liquid chamber 6 of the liquid discharge head 3 via the rear throttle plate 4. In the orifice plate 2, discharge ports 8 that discharge the pressurized ink as droplets are formed corresponding to the individual liquid chambers 6.

  Further, the liquid discharge head unit 1 includes first, second, and third flexible substrates (FPCs) 9 drawn out from the end face of the liquid discharge head 3 as wiring from the liquid discharge head 3 to the outside, 10 and 11.

  A method for manufacturing the liquid discharge head of this embodiment will be described below. An outline of the manufacturing method is shown in the flowchart of FIG. Here, a method of manufacturing the liquid discharge head unit 1 in which the discharge ports 8 are arranged in 5 rows and 5 columns will be described. However, the number of discharge ports 8 varies depending on the number of grooves and the number of stacked piezoelectric substrates. A discharge head unit can be manufactured.

(Processing of the first piezoelectric substrate)
FIG. 4 is a plan view showing an example of a first piezoelectric substrate in which a plurality of grooves are formed. In the example shown in FIG. 4, five sets of groove groups corresponding to five individual liquid chambers 6 and six air chambers 7 (see FIG. 2) are formed in the first piezoelectric substrate 12. Examples of the first piezoelectric substrate 12 include a 19 mm × 70 mm × 0.24 mm PZT (lead zirconate titanate) substrate.

  In the following description, only one set of the five sets formed on the first piezoelectric substrate 12 is illustrated.

(Groove processing)
First, a method for forming the first piezoelectric substrate 12 shown in FIG. 4 will be described with reference to FIG. FIG. 5 is a perspective view for explaining a method of forming the first piezoelectric substrate 12 shown in FIG.

  As shown in FIG. 5A, a plate-shaped first piezoelectric substrate 12 made of a piezoelectric material and having a desired size and shape is prepared. Then, a first exposure alignment groove 13 (see FIG. 4) is formed in the first piezoelectric substrate 12 by grinding with a superabrasive wheel.

  The first exposure alignment groove 13 is positioned by the distance from the end of the first piezoelectric substrate 12. Prior to this step, a metal pattern or the like to be a mark may be formed on the first piezoelectric substrate 12 by photolithography, and the position of the first exposure alignment groove 13 may be determined based on the metal pattern.

  Next, as shown in FIG. 5B, a plurality of first grooves 14 extending in parallel with each other are formed on one surface of the first piezoelectric substrate 12. In the present embodiment, the plurality of first grooves 14 extend along the first direction X.

  The first groove 14 is positioned with reference to the first exposure alignment groove 13 (see FIG. 4). A part of the first groove 14 functions as the individual liquid chamber 6 (see FIG. 2). Of the surfaces of the first piezoelectric substrate 12, the surface on which the first groove 14 is formed is referred to as a groove forming surface 15 or a first surface A1.

  The first groove 14 is formed, for example, by grinding using a superabrasive wheel. In the present embodiment, the superabrasive wheel (not shown) is a side opposite to the first side surface 16 from the first side surface 16 facing the first direction X in the surface of the first piezoelectric substrate 12. The first piezoelectric substrate 12 is moved away from the first piezoelectric substrate 12 before reaching the second side surface 17. Therefore, the first groove 14 extends along the first direction X from the first side surface 16 to the front of the second side surface 17.

  The size and pitch of the first grooves 14 are determined from the size of the individual liquid chambers 6 (see FIG. 2) and the arrangement density of the individual liquid chambers 6. For example, the plurality of first grooves 14 can be formed with a groove width of 0.12 mm, a groove depth of 0.12 mm, and a groove pitch of 0.706 mm (equivalent to 36 npi).

  The groove width refers to the dimension of the groove in the direction in which the groove extends and the direction that intersects the depth direction of the groove. Further, the pitch of the grooves refers to an interval in the second direction between a plurality of adjacent grooves in the second direction.

  Furthermore, in addition to the first groove 14 serving as the individual liquid chamber 6 (see FIG. 2), grooves (not shown) are formed on both outer sides thereof, so that it can function as an adhesive escape groove in a subsequent joining step. it can. Further, as shown in FIG. 4, a first bonding alignment groove 18 is formed as a mark for alignment in a later chip stacking step.

  Subsequently, as shown in FIG. 5C, a plurality of second grooves 19 extending in parallel with the first groove 14 are formed on both sides of the groove forming surface 15 on the first groove 14. The second groove 19 is positioned with reference to the first exposure alignment groove 13 (see FIG. 4).

  A part of the second groove 19 functions as the air chamber 7 (see FIGS. 1 and 2). In contrast to the first groove 14, the second groove 19 extends from the second side surface 17 to the front of the first side surface 16 along the first direction X.

  The size of the second groove 19 is determined from the size of the air chamber 7 (see FIG. 2). For example, the wall width between the first groove 14 and the second groove 19 can be 0.12 mm, the groove width of the second groove 19 can be 0.346 mm, and the groove depth can be 0.14 mm.

(Electrode formation)
When the first and second grooves 14 and 19 are formed, the first electrode (SIG) 20 is formed on the inner surface of the first groove 14 as shown in FIG. A second electrode (GND) 21 is formed on at least one of the inner side surfaces of 19. The second electrode (GND) 21 may be formed on all inner surfaces of the second groove 19. A metal film is formed on the first and second side surfaces 16 and 17.

  The patterns of the first electrode (SIG) 20 and the second electrode (GND) 21 are formed by lift-off, laser, polishing, or the like. In the description of this document, forming a pattern may be referred to as patterning.

  As an example, an electrode patterning method by lift-off will be described with reference to FIGS. 6A to 6D are cross-sectional views taken along the line A-A ′ of FIG.

  Since the first and second grooves 14 and 19 are formed on the groove forming surface 15, it is difficult to form a uniform resist film by an ordinary spin coater coating method. Therefore, film resist laminating and application by a spray coater are suitable. Since it is difficult to uniformly expose the inside of the groove, it is preferable to use a negative type resist that only needs to expose the outside of the groove.

  First, as shown in FIG. 6A, a film resist 22 is laminated on the groove forming surface 15 of the first piezoelectric substrate 12 to close the openings of the first and second grooves 14 and 19. Since the first piezoelectric substrate 12 is a sintered body, voids of about 10 μm are scattered. Therefore, if the film resist 22 is too thin, pattern defects will occur in the film resist 22 above the void. Therefore, it is preferable to use a film resist 22 having a sufficient thickness, for example, 40 μm or more.

  Next, as shown in FIG. 6B, the film resist 22 is patterned by exposure and development. In the lift-off, a resist pattern is formed by photolithography so that the film resist 22 remains in a portion where the electrode pattern is not desired to be left. At this time, it is preferable to make the pattern width of the film resist 22 smaller than the width of the groove side wall so that the metal film is formed on the entire side wall of the groove in the subsequent step. For example, when the width of the groove sidewall is 0.12 mm, the resist pattern width is 0.06 mm.

  Subsequently, as shown in FIG. 6C, a metal film to be an electrode is formed on the groove forming surface 15 and the inner surfaces of the first and second grooves 14 and 19 by sputtering or vapor deposition. Sputtering is excellent in film formation on the trench sidewall, and vapor deposition is excellent in patterning at lift-off. At this time, in the region of the groove forming surface 15 where the film resist 22 remains, the metal film is not formed on the groove forming surface 15 but formed on the film resist 22.

  Then, as shown in FIG. 6D, by removing the film resist 22 remaining on the first piezoelectric substrate 12, the metal film formed on the film resist 22 is peeled off together with the film resist 22, A desired metal film pattern can be obtained. The metal film remaining on the inner surface of the first groove 14 becomes the first electrode (SIG) 20, and the metal film remaining on the inner surface of the second groove 19 becomes the second electrode (GND) 21. .

  As a method of forming the metal film, for example, a method of forming Cr as a film with a thickness of approximately 20 nm as an underlayer and further depositing Au as a film with a thickness of approximately 1000 nm as an electrode layer can be cited. Alternatively, Cr is deposited to a thickness of approximately 20 nm as the underlayer, Pd is deposited to a thickness of approximately 50 nm on the Cr film, Ni plating is performed to a thickness of approximately 1000 nm using the Pd film as a seed layer, and only the surface of the Ni film is replaced with Au. Also, the metal film can be formed. The metal film forming method mentioned in the latter is thin because the film thickness at the time of lift-off is small, so that burrs are less likely to remain and the patterning property is improved. In addition, Au is used only on the surface, so that the cost is low.

  Further, a metal film pattern can be formed by laser irradiation or polishing.

  In the method by laser irradiation or polishing, a metal film is first formed on the entire surface by sputtering, vapor deposition, electroless plating, or the like. At this time, a metal film is also formed on the first and second side surfaces 16 and 17. A desired electrode pattern is obtained by removing unnecessary portions of the formed metal film, that is, the metal film formed between the first and second grooves 14 and 19 by laser or polishing.

  When the first electrode (SIG) 20 and the second electrode (GND) 21 are formed by the method shown in FIGS. 6A to 6D, as shown in FIG. A common wiring 24 and a third electrode (GND) 25 are formed on the substrate 12. The common wiring 24 and the third electrode (GND) 25 are formed on the surface 23 of the surface of the first piezoelectric substrate 12 opposite to the groove forming surface 15. The surface 23 may also be referred to as the second surface A2.

  The common wiring 24 and the third electrode (GND) 25 extend along the second direction Y that intersects the first direction X and extends along the surface 23, and are electrically insulated from each other. The common wiring 24 and the third electrode (GND) 25 are patterned by a method such as lift-off or etching using photolithography of a photoresist, or a method of removing unnecessary portions by laser, dicing, milling, or the like.

  In particular, unlike the case where the first electrode (SIG) 20 and the second electrode (GND) 21 shown in FIG. 5 (d) are formed, the surface 23 has no irregularities, so even with resist application by normal spin coating. A uniform resist film can be formed.

  A method for patterning the common wiring 24 and the third electrode (GND) 25 using a lift-off method by photolithography will be described with reference to FIGS. 6E to 6H are B-B ′ cross-sections of FIG.

  As shown in FIG. 6E, a resist 26 is formed on the surface 23. Then, as shown in FIG. 6F, the resist 26 is patterned. Thereafter, a metal film is formed on the surface 23 as shown in FIG. At this time, in the region of the surface 23 where the resist 26 remains, the metal film is not formed on the surface 23 but formed on the resist 26. Since the metal film is formed by the same method as the method for forming the first and second electrodes, the description of the method for forming the metal film is omitted here.

  When the metal film is formed on the surface 23, the resist 26 is removed as shown in FIG. As a result, the metal film formed on the resist 26 is peeled off together with the resist 26, and a desired metal film pattern is obtained. The metal film remaining in the region on the first side surface 16 side of the surface 23 becomes the common wiring 24, and the metal film remaining in the region on the second side surface 17 side of the surface 23 is connected to the third electrode (GND) 25. Become.

  The common wiring 24 is electrically connected to the first electrode (SIG) 20 through a metal film formed on the first side surface 16. On the other hand, the third electrode (GND) 25 is electrically connected to the second electrode (GND) 21 through a metal film formed on the second side surface 17.

(polarization)
When the common wiring 24 and the third electrode (GND) 25 are formed, the first piezoelectric substrate 12 is subjected to polarization as shown in FIG. By the polarization process of the first piezoelectric substrate 12, the walls (side walls and bottom wall) forming the first groove 14 are polarized in three different directions.

  In the polarization treatment, a voltage that becomes a high electric field of about 1 to 2 kV / mm is applied to the first electrode (SIG) 20, the second and third electrodes in a state where the first piezoelectric substrate 12 is heated to about 100 to 150 ° C. The electrodes (GND) 21 and 25 are applied for a predetermined time. At this time, the first electrode (SIG) 20 is set to a positive potential, and the second electrode (GND) 21 and the third electrode (GND) 25 are set to a GND potential.

  Since the common wiring 24 and the third electrode (GND) 25 are relatively large, the power supply device 27 that generates a high electric field can be obtained by using the common wiring 24 and the third electrode (GND) 25 as an electrode pad. The piezoelectric substrate 12 can be connected relatively easily.

  The distance between the first electrode (SIG) 20 and the second and third electrodes (GND) 21 and 25 is as narrow as 0.06 mm, and it is in the air when a high electric field of 1 to 2 kV / mm is applied in air. There is a high possibility of causing discharge and creeping discharge. In order to prevent air discharge and creeping discharge, it is desirable to perform polarization treatment in highly insulating oil such as silicone oil (dielectric breakdown voltage: 10 kV / mm or more). Silicone oil can be removed after polarization by a hydrocarbon solvent such as xylene, benzene or toluene, or a chlorinated hydrocarbon solvent such as methylene chloride, 1.1.1-trichloroethane or chlorobenzene.

  After the polarization process, an aging process is performed as necessary. The aging process is a process for stabilizing the piezoelectric characteristics of the first piezoelectric substrate 12 that has been subjected to the polarization process, by holding the first piezoelectric substrate 12 in a heated state for a certain period of time. For example, the aging process is completed by leaving the first piezoelectric substrate 12 subjected to the polarization process in an oven at 100 ° C. for 10 hours.

(Electrode separation)
When the polarization process is completed, the second electrode (GND) 21 and the third electrode (GND) 25 are separated into two, as shown in FIGS. 5 (g) and 6 (i). Specifically, the intermediate portion of the second electrode (GND) 21 and the third electrode (GND) 25 in the first direction X is peeled off from the first piezoelectric substrate 12. As a result, the second electrode (GND) 21 becomes two second electrode portions 21a and 21b arranged in the first direction X, and the third electrode (GND) 25 has two two electrodes arranged in the first direction X. The third electrode portions 25a and 25b are formed.

  The separation position 28a for separating the second electrode portions 21a and 21b is the first and second chip separation positions 29 and 29 at the time of chip separation (see FIGS. 5 (h) and (i)) as the next step. What is necessary is just to set it as the arbitrary positions between 30. The separation position 28b that separates the third electrode portions 25a and 25b may be any position between the first and second chip separation positions 29 and 30.

  For example, in the present embodiment, in the chip separation step, the first piezoelectric substrate 12 having a size of 19 mm × 70 mm × 0.24 mm is separated into 10 mm × 10 mm × 0.24 mm chips. In such a case, the positions advanced 8 mm from the second chip separation position 30 toward the first chip separation position 29 can be set as the separation positions 28a and 28b.

  The third electrode (GND) 25 is separated by dicing processing of the first piezoelectric substrate 12. Since the surface 23 is flat, the third electrode (GND) 25 may be diced using a dicing blade 31 to a depth greater than the thickness of the third electrode (GND) 25.

  Of course, the third electrode (GND) 25 is separated not only by dicing but also by a method of removing unnecessary portions by lift-off using a photolithography of a photoresist, etching, laser, milling, or the like.

  Since the second electrode 21 is formed on the inner surface of the second groove 19, separation by dicing is difficult. Therefore, when the second electrode 21 is separated, it is preferable to use a method of removing unnecessary portions by lift-off, etching, laser processing, or the like using photoresist photolithography.

(Chip separation)
When the second electrode (GND) 21 and the third electrode (GND) 25 are separated from each other, as shown in FIG. 5 (h), from the first chip separation position 29 in the first piezoelectric substrate 12. The portion on the second side surface 17 side is removed. The first chip separation position 29 crosses the plurality of first grooves 14 in the second direction Y. Therefore, the first groove 14 of the first piezoelectric substrate 12 after removing the portion passes through the groove forming surface 15 of the first piezoelectric substrate 12.

  In this step, the metal film on the second side surface 17 is also removed. Therefore, the second electrode portions 21a and 21b in each second groove 19 and the third electrode portions 25a and 25b on the surface 23 are electrically separated from each other.

  Examples of the method for removing the portion of the first piezoelectric substrate 12 include dicing, polishing, and laser ablation.

  Subsequently, as shown in FIG. 5I, the portion of the first piezoelectric substrate 12 on the first side face 16 side from the second chip separation position 30 is removed. The first chip separation position 30 crosses the plurality of second grooves 19 in the second direction Y. Therefore, the second groove 19 of the first piezoelectric substrate 12 after removing the portion of the first piezoelectric substrate 12 on the first side face 16 side from the second chip separation position 30 is not It passes through the groove forming surface 15 of the piezoelectric substrate 12.

  In this step, the metal film on the first side surface 16 is also removed. Therefore, the first electrode (SIG) 20 in each first groove 14 and the common wiring 24 on the surface 23 are electrically separated from each other.

  By setting the second chip separation position 30 so as not to cross the plurality of second grooves 19, the second groove 19 does not pass over the groove forming surface 15 of the first piezoelectric substrate 12. Therefore, when the second groove 19 becomes the air chamber 7 (see FIG. 2), the air chamber 7 does not penetrate the liquid ejection head 3 (see FIGS. 1 and 2).

  A portion of the first piezoelectric substrate 12 on the second side surface 17 side from the first chip separation position 29 and a portion on the first side surface 16 side from the second chip separation position 30 are removed. The first piezoelectric substrate 12 on which 5 sets of groove groups shown in 4 are formed is separated for each set. Accordingly, the first piezoelectric substrate 12 is cut into five small chips having a size of 10 mm × 10 mm × 0.24 mm.

(Processing of the second piezoelectric substrate)
FIG. 7 is a plan view showing an example of a second piezoelectric substrate in which a plurality of grooves are formed. In the example shown in FIG. 7, five sets of groove groups corresponding to five air chambers 7 are formed in the second piezoelectric substrate 32. An example of the second piezoelectric substrate 32 is a PZT substrate of 15 mm × 70 mm × 0.43 mm.

  In the following description, only one set of the five sets of groove groups formed on the second piezoelectric substrate 32 is illustrated.

(Groove processing)
A method of forming the second piezoelectric substrate 32 shown in FIG. 7 will be described with reference to FIG. FIG. 8 is a perspective view for explaining a method of forming the second piezoelectric substrate 12 shown in FIG.

  First, a flat plate-like second piezoelectric substrate 32 having a desired thickness and shape is prepared. Then, a second exposure alignment groove 33 (see FIG. 7) is formed on the second piezoelectric substrate 32 by grinding with a superabrasive wheel.

  The second exposure alignment groove 33 is positioned by the distance from the end of the second piezoelectric substrate 32. Prior to this step, a metal pattern or the like serving as a mark may be formed on the second piezoelectric substrate 32 by photolithography, and the position of the second exposure alignment groove 33 may be determined based on the metal pattern.

  As shown in FIG. 8A, a plurality of third grooves 34 extending in parallel with each other are formed in the second piezoelectric substrate 32. In the present embodiment, the plurality of third grooves 34 extend in the first direction X.

  The third groove 34 is positioned with reference to the second exposure alignment groove 33 (see FIG. 7). A part of the third groove 34 functions as an air chamber 7 (see FIG. 2) adjacent to the individual liquid chamber 6 (see FIG. 2). In addition, the surface in which the 3rd groove | channel 34 was formed among the 2nd piezoelectric substrates 32 is called the groove | channel formation surface 35 or 1st surface B1.

  The third groove 34 is formed, for example, by grinding using a superabrasive wheel. In the present embodiment, the superabrasive wheel (not shown) moves along the first direction X from the first side surface 36 of the second piezoelectric substrate 32 facing the first direction X, and the first Before reaching the second side surface 37 opposite to the side surface 36, it is separated from the second piezoelectric substrate 32. Accordingly, the third groove 34 extends from the first side surface 36 to the front of the second side surface 37 along the first direction X.

  The size and pitch of the third grooves 34 are determined from the size of the air chamber 7 (see FIG. 2) and the arrangement density of the air chambers 7. For example, the plurality of third grooves 34 can be formed with a groove width of 0.36 mm, a groove depth of 0.31 mm, and a groove pitch of 0.706 mm (equivalent to 36 npi).

  Furthermore, by forming grooves (not shown) on both outer sides in addition to the third groove 34 serving as the air chamber 7 (see FIG. 2), it can function as an adhesive escape groove in a subsequent joining step. . Further, as shown in FIG. 7, a second bonding alignment groove 38 is formed as a mark for alignment in a later chip stacking step.

(Electrode formation)
Subsequently, as shown in FIG. 8B, a fourth electrode (GND) 39 is formed on at least the bottom surface of the inner surface of the third groove 34. The fourth electrode (GND) 39 may be formed on all inner surfaces of the third groove 34.

  Further, the fourth electrode (GND) 39 may be formed on the groove forming surface 35, but the end surface when the second piezoelectric substrate 32 is made into a small chip and the fourth electrode (GND) 39 are not in contact with each other. Thus, it is preferable to pattern the fourth electrode (GND) 39 in which the groove forming surface 35 is formed. The pattern of the fourth electrode (GND) 39 is formed by lift-off, laser, polishing, or the like.

As an example, an electrode patterning method by lift-off will be described with reference to FIGS. FIGS. 9A to 9D are cross-sectional views taken along the line CC ′ of FIG. 8A. Since the third groove 34 is formed on the groove forming surface 35, in the coating method using a normal spin coater, It is difficult to form a uniform resist film. Therefore, film resist laminating and application by a spray coater are suitable. Since it is difficult to uniformly expose the inside of the groove, it is preferable to use a negative type resist that only needs to expose the outside of the groove.

  First, as shown in FIG. 9A, the film resist 22 is laminated on the groove forming surface 35 of the second piezoelectric substrate 32. Next, as shown in FIG. 9B, a resist pattern is formed by photolithography so that the film resist 22 remains in a portion where the electrode pattern is not desired to be left.

  Further, as shown in FIG. 9C, a metal film to be an electrode is formed on the inner surface of the groove forming surface 35 and the third groove 34 by sputtering or vapor deposition. At this time, in the region where the film resist 22 remains on the groove forming surface 35, the metal film is not directly formed on the groove forming surface 35 but formed on the film resist 22.

  Then, as shown in FIG. 9D, by removing the film resist 22 remaining on the second piezoelectric substrate 32, the metal film formed on the film resist 22 is peeled off together with the film resist 22, A desired metal film pattern can be obtained. The remaining metal film becomes the fourth electrode (GND) 39.

  As a method of forming the metal film, for example, a method of forming Cr as a film with a thickness of approximately 20 nm as an underlayer and further depositing Au as a film with a thickness of approximately 1000 nm as an electrode layer can be cited. Alternatively, Cr is deposited to a thickness of approximately 20 nm as the underlayer, Pd is deposited to a thickness of approximately 50 nm on the Cr film, Ni plating is performed to a thickness of approximately 1000 nm using the Pd film as a seed layer, and only the surface of the Ni film is replaced with Au. Also, the metal film can be formed. The metal film forming method mentioned in the latter is thin because the film thickness at the time of lift-off is small, so that burrs are less likely to remain and the patterning property is improved. In addition, Au is used only on the surface, so that the cost is low.

  Further, a metal film pattern can be formed by laser irradiation or polishing.

  In the method by laser irradiation or polishing, a metal film is first formed on the entire surface by sputtering, vapor deposition, electroless plating, or the like. Then, an unnecessary portion of the formed metal film, that is, the metal film formed on the groove forming surface 35 is removed by laser or polishing, thereby obtaining a desired electrode pattern.

  When the fourth electrode (GND) 39 is formed by the steps shown in FIGS. 9A to 9D, as shown in FIG. 8C, the groove forming surface 35 of the second piezoelectric substrate 32 and A plurality of fifth electrodes (SIG) 41 are formed on the opposite surface 40. Note that the surface 40 may be referred to as a second surface B2.

  The plurality of fifth electrodes (SIG) 41 are formed at positions corresponding to the third grooves 34 and extend along the first direction. Therefore, the fifth electrodes (SIG) 41 adjacent in the second direction Y are electrically insulated from each other.

  The fifth electrode (SIG) 41 is patterned by a method such as lift-off or etching using photolithography of a photoresist, or a method of removing unnecessary portions by laser, dicing, milling, or the like.

  In particular, unlike the case where the fourth electrode (GMD) 39 shown in FIG. 8B is formed, the surface 23 is not uneven. Therefore, a uniform resist film can be formed even by resist application by normal spin coating. As in the case of forming the fourth electrode (GND) 39, a resist is formed, and after patterning, a metal layer is formed and the resist is removed to form the fifth electrode (SIG) 41. . It is also possible to form a relatively thick electrode by depositing a Pd thin film and plating a metal using this as a seed layer.

  The width of the electrode pattern of the fifth electrode (SIG) 41 may be approximately the same as the groove width of the third groove 34. However, in consideration of alignment errors during stacking and exposure, for example, 0.18 mm It is preferable to set the degree.

(polarization)
When the fourth electrode (GND) 39 and the fifth electrode (SIG) 41 are formed, the second piezoelectric substrate 32 is subjected to polarization treatment. By the polarization treatment of the second piezoelectric substrate 32, the bottom wall of the third groove 34 is polarized in the depth direction of the third groove 34.

  In the polarization treatment, the second piezoelectric substrate 32 is heated to about 100 to 150 ° C., and about 1 to 2 kV / mm between the fifth electrode (SIG) 41 and the fourth electrode (GND) 39. This is done by applying a high electric field of a predetermined time. At this time, the fifth electrode (SIG) 41 is set to a positive potential, and the fourth electrode (GND) 39 is set to a GND potential.

  Note that the second piezoelectric substrate 32 may be subjected to polarization processing in a flat plate state before the groove processing. In the polarization treatment, electrodes are respectively formed on the groove forming surface 35 and the surface 40 of the flat plate-like second piezoelectric substrate 32 and heated to about 100 to 150 ° C., and about 1 to 2 kV / mm between the electrodes. Is completed by applying a high electric field of a predetermined time. By the polarization process, the second piezoelectric substrate 32 is uniformly polarized in a direction perpendicular to the main plane of the plate-shaped second piezoelectric substrate 32.

  The polarization treatment may be performed in insulating oil as in the first piezoelectric substrate 12, or may be performed in air. After the polarization treatment, the electrodes on the front and back surfaces of the second piezoelectric substrate 32 are removed. Removal is performed by etching or polishing.

(Electrode separation)
As shown in FIGS. 8D and 9E, the fourth electrode (GND) 39 is separated into two. Specifically, a separation groove 42 extending in the second direction Y and having a deeper groove depth than the third groove 34 is formed on the groove forming surface 35 of the second piezoelectric substrate 32. Due to the separation groove 42, the fourth electrode (GND) 39 becomes two fourth electrode portions 39 a and 39 b arranged along the first direction X.

  The position of the separation groove 42 is a position between the first and second chip separation positions 43 and 44 at the time of chip separation (see FIG. 8E) as the next step, and a plurality of third grooves. The groove 34 may be positioned so as to cross the second direction Y.

  For example, in the present embodiment, the second piezoelectric substrate 32 having a size of 15 mm × 70 mm × 0.43 mm is separated into 10 mm × 10 mm × 0.43 mm chips in the chip separation step. Therefore, the position advanced 8 mm from the second chip separation position 44 toward the first chip separation position 43 can be set as the position of the separation groove 42.

  The separation groove 42 having a deeper groove depth than the third groove 34 is formed by grinding. As a method of separating the fourth electrode (GND) 39, a method of removing unnecessary portions by lift-off using a photolithography of a photoresist, etching, laser processing, or the like may be used.

(Chip separation)
When the fourth electrode (GND) 39 is separated, as shown in FIG. 8E, a portion of the second piezoelectric substrate 32 on the second side surface 37 side from the first chip separation position 43 is removed. Remove.

  In the present embodiment, the first chip separation position 43 crosses the plurality of third grooves 34 in the second direction Y. Therefore, the third groove 34 of the second piezoelectric substrate 32 after removing the portion on the second side surface 37 side from the first chip separation position 43 is on the groove forming surface 35 of the second piezoelectric substrate 32. I'm going through.

  Further, the portion of the second piezoelectric substrate 32 on the first side surface 36 side is removed from the second chip separation position 44.

  Examples of the method for removing the portion include dicing, polishing, and laser ablation. Even if a metal film is formed on the first and second side surfaces 36 and 37, it is removed by this step. Therefore, even if the fifth electrode (SIG) 41 formed on the inner surface of each third groove 34 in the state shown in FIG. 8C is electrically connected through the metal film, respectively. Through this step, each fifth electrode (SIG) 41 is electrically insulated.

  When the portion of the second piezoelectric substrate 32 on the second side surface 37 side from the first chip separation position 43 and the portion on the first side surface 16 side from the first chip separation position 44 are removed, FIG. The second piezoelectric substrate 32 in which the groove groups for five sets shown in FIG. 7 are formed is separated for each set. Accordingly, the second piezoelectric substrate 32 is cut into five small chips having a size of 10 mm × 10 mm × 0.43 mm.

(Top plate processing)
Subsequently, the third and fourth piezoelectric substrates 45 and 46 (FIG. 2) are processed. The third and fourth piezoelectric substrates 45 and 46 are stacked on the uppermost and lowermost portions of the liquid discharge head 3 and correct the warpage of the stacked first and second piezoelectric substrates 12 and 32. Have The size of these substrates can be, for example, 10 mm × 10 mm × 3 mm.

  FIG. 10 is a perspective view showing another example of the fourth piezoelectric substrate 46. As shown in FIG. 10, a plurality of grooves may be formed in the fourth piezoelectric substrate 46. When the fourth piezoelectric substrate 46 shown in FIG. 10 is provided at the bottom of the liquid discharge head 3 (see FIG. 2), the second piezoelectric substrate 46 is interposed between the first piezoelectric substrate 12 and the fourth piezoelectric substrate 46. The piezoelectric substrate 32 may not be provided. Further, when the fourth piezoelectric substrate 46 is processed into the shape shown in FIG. 10, it is not necessary to form electrodes on the fourth piezoelectric substrate 46.

(Laminated)
Next, a laminating process for laminating the first, second, third and fourth piezoelectric substrates 12, 32, 45, 46 will be described with reference to FIG. FIG. 11A is a perspective view for explaining a process of laminating the first and second piezoelectric substrates 12 and 32. FIG. 11B is a perspective view for explaining a step of laminating the third and fourth piezoelectric substrates 45 and 46 on a laminate in which a plurality of first and second piezoelectric substrates 12 and 32 are laminated. is there. However, the electrode is omitted in FIG.

  Through the steps so far, the first piezoelectric substrate 12 is formed with the first groove 14 that becomes the individual liquid chamber 6 (see FIG. 2) and the second groove 19 that becomes the air chamber 7 (see FIG. 2). Has been. A first electrode (SIG) 20 is formed on the inner surface of the first groove 14, and a second electrode (GND) 21 is formed on the inner surface of the second groove 19 (FIG. 6). (See (i)). The second electrode (GND) 21 is separated into second electrode portions 21a and 21b. Further, a third electrode (GND) 25 separated into two third electrode portions 25a and 25b is formed on the surface 23 of the first piezoelectric substrate 12 (see FIG. 6 (i)).

  The second piezoelectric substrate 32 is formed with a third groove 34 that becomes the air chamber 7 (see FIG. 2). A fourth electrode (GND) 39 separated into two fourth electrode portions 39a and 39b is formed on the inner surface of the third groove 34 (see FIG. 9E). And the 5th electrode (SIG) 41 is formed in the position corresponding to the 3rd groove | channel 34 of the surface 40 of the 2nd piezoelectric substrate 32 (refer FIG.8 (c)).

  First, as shown in FIG. 11A, the first and third grooves 14 and 34 are aligned in the extending direction, and the first and third grooves 14 and 34 are aligned with each other. The groove forming surface 15 of the piezoelectric substrate 12 and the surface 40 of the second piezoelectric substrate 32 are joined. By joining the groove forming surface 15 with the surface 40, the openings of the first and second grooves 14 and 19 are covered with the surface 40. As a result, the first groove 14 becomes the individual liquid chamber 6, and the second groove 19 becomes the air chamber 7.

  For the bonding, for example, an epoxy adhesive can be used. When the adhesive is used, the first and second grooves 14 and 19 may be filled with the adhesive. In order to prevent such a situation, it is desirable to appropriately control the amount of the adhesive when applying the adhesive to the first and / or second piezoelectric substrates 12 and 32.

  As a method for applying the adhesive, a thin uniform adhesive layer is formed on a separately prepared flat substrate by spin coating or screen printing, and the first or second piezoelectric substrate 12, And a method of transferring the adhesive layer by pressing 32. According to this method, a thin and uniform adhesive layer can be formed on the first and / or second piezoelectric substrates 12 and 32.

  After applying the adhesive, the first and second piezoelectric substrates 12 and 32 are positioned in a state where there is a minute gap between the first and second piezoelectric substrates 12 and 32, and the first and second piezoelectric substrates are positioned. 12 and 32 are pressure bonded. As a measure of the thickness of the adhesive, it is appropriate that the thickness of the adhesive layer before bonding is about 4 μm and the thickness after bonding is about 2 μm.

  Further, in order to reduce the protrusion of the adhesive into the first and second grooves 14 and 19, grooves are formed outside the row of the first and second grooves 14 and 19, and the adhesive is released. It may be used as a groove for the purpose. The first bonding alignment groove 18 may be used as a groove for releasing the adhesive.

  The alignment at the time of stacking can be performed by abutting the end face of the piezoelectric substrate formed into a chip against a positioning pin, and in order to further improve the positioning accuracy, alignment by a camera may be performed. As a mark used for alignment by the camera, a chip edge, a groove, an alignment mark patterned at the time of electrode formation, or the like can be used.

  As shown in FIG. 11 (b), a plurality of units are joined with the unit in which the first and second piezoelectric substrates 12 and 32 are joined as one unit. At this time, the surface 23 of the first piezoelectric substrate 12 of one unit is joined to the groove forming surface 35 of the second piezoelectric substrate 32 of the other unit. As a result, the opening of the third groove 34 is covered by the surface 40, and the third groove 34 becomes the air chamber 7.

  Further, a laminated body in which a plurality of first and second piezoelectric substrates 12 and 32 are laminated is sandwiched between third and fourth piezoelectric substrates 45 and 46, and the laminated body and the third and fourth piezoelectric substrates 45 are sandwiched. , 46 are joined. The third and fourth piezoelectric substrates 45 and 46 are bonded to the surface 23 of the first piezoelectric substrate 12 and the groove forming surface 35 of the second piezoelectric substrate 32 located at the end of the laminate.

  The liquid ejection head 3 is completed by joining the third and fourth piezoelectric substrates 45 and 46 to a laminate formed by laminating a plurality of first and second piezoelectric substrates 12 and 32. The first and fifth electrodes (SIG) 20 and 41 (see FIGS. 5 and 8) serve as inner electrodes provided on the inner surface of the individual liquid chamber 6.

  The second, third and fourth electrodes (GND) 21, 25, 39 (see FIGS. 5 and 8) serve as outer electrodes provided on the outer surface of the individual liquid chamber 6. The outer electrode is separated into two in the direction in which the individual liquid chamber 6 passes through the laminate in which the plurality of first and second piezoelectric substrates 12 and 32 are laminated.

  The third and fourth piezoelectric substrates 45 and 46 are flat plates on which no electrode pattern is formed. The third and fourth piezoelectric substrates 45 and 46 do not have to be piezoelectric bodies. However, when heating is required at the time of bonding, the thermal expansion coefficient is the same as or close to that of the first and second piezoelectric substrates 12 and 32. It is desirable to be formed of a material having an expansion coefficient.

(Polishing)
Of the surface of the liquid discharge head 3 formed by the laminating process, the first and second end surfaces 47 and 48 in which the openings of the individual liquid chambers 6 are formed are flattened by polishing. Sprinkling can be used for polishing. For the subsequent electrode formation step, the surface roughness is preferably about Ra 0.4 μm. In order to attach the orifice plate 2 and the rear diaphragm plate 4 with high accuracy, the flatness of the first and second end faces 47 and 48 is within 10 μm, and the parallelism between the first and second end faces 47 and 48 is It is preferable to be within 30 μm.

(Formation of common electrode on first end face)
Next, second, third, and fourth electrode portions 21a, 25a, 39a provided on the inner surface of each air chamber 7 on the first end surface 47 of the liquid discharge head 3 (FIG. 6 (i), FIG. 9 (e)) is formed.

  FIG. 12 shows a perspective view of the liquid discharge head 3 in which the lead wiring 49a is formed. The lead wiring 49 a is routed from the first end face 47 of the liquid discharge head 3 to the upper end face 50 of the liquid discharge head 3. In a process described later, a portion of the lead wiring 49a formed on the upper end surface 50 is connected to the second flexible substrate 10 (see FIGS. 1 and 2).

  The electrode patterning of the first end face 47 will be described with reference to FIG. An electrode patterning method is shown in FIG. FIG. 13 is a D-D ′ cross section in FIG. 12.

  Openings such as the individual liquid chamber 6 and the air chamber 7 are formed in the first end surface 47, and the first end surface 47 has irregularities. Therefore, it is difficult to form a uniform resist film by an ordinary spin coater method. Therefore, a method of forming a resist film using a film resist laminate is suitable. A negative resist is used as the film resist.

  In the lift-off, a resist pattern is formed by photolithography so that the resist remains in a portion where the electrode pattern is not desired to remain. Then, a metal layer serving as an electrode is formed on the first end face 47 by sputtering or vapor deposition. At this time, the metal layer is not formed directly on the first end face 47 in the portion of the first end face 47 where the resist remains, but is formed on the resist. Then, by removing the resist, the metal film formed on the resist is peeled off together with the resist, and a desired metal film pattern is finally obtained.

  First, a film resist 51 is laminated on the first end face 47 as shown in FIG. Next, the opening and opening edge of the air chamber 7 are exposed by exposure and development (FIG. 13B). At this time, the opening and the opening edge of the individual liquid chamber 6 (see FIGS. 2 and 11) are covered with the film resist 51.

  Further, an electrode layer is formed as shown in FIG. The electrode layer becomes a part of the lead wiring 49a. The second, third and fourth electrode portions 21a, 25a and 39a (see FIGS. 6 (i) and 9 (e)) in the air chamber 7 are electrically connected to each other by the lead wiring 49a. At this time, a mask is also formed on the upper end surface 50 to form an electrode layer, so that a portion of the lead-out wiring 49a connected to the second flexible substrate 10 (see FIGS. 1 and 2) is formed. Is done.

  Next, as shown in FIG. 13D, the film resist 51 is removed. As a result, the electrode layer is lifted off, and the lead-out wiring 49a can be formed in a desired pattern.

  FIG. 14 shows an electrode pattern on the E-E ′ cross section in FIG. 12. The lead wiring 49 a is electrically connected to the second electrode portion 21 a in the air chamber 7, but is not electrically connected to the first electrode (SIG) 20 in the individual liquid chamber 6. .

  As a method for forming the lead-out wiring 49a, for example, a method of forming a Cr film with a thickness of about 20 nm as a base layer and a film of Au with a thickness of about 1000 nm as an electrode layer can be cited. Alternatively, Cr is deposited to a thickness of approximately 20 nm as the underlayer, Pd is deposited to a thickness of approximately 50 nm on the Cr film, Ni plating is performed to a thickness of approximately 1000 nm using the Pd film as a seed layer, and only the surface of the Ni film is replaced with Au. Also, the metal film can be formed.

  Note that the metal film forming method mentioned in the latter is thinner because the film thickness at the time of lift-off is small, so that burrs are less likely to remain, and the patterning property is improved.

  Between each of the piezoelectric substrates 12, 32, 45, and 46 (see FIG. 11), there is a gap of about 1 to 2 μm due to the adhesive layer, but if the lead wire 49a has a thickness of 1000 nm, the lead wire 49a It is not divided by the gap.

(Formation of common electrode on second end face)
Next, second, third and fourth electrode portions 21b, 25b, 39b provided on the inner surface of each air chamber 7 on the second end surface 48 of the liquid discharge head 3 (FIG. 6 (i), FIG. 9 (e)) is formed.

  FIG. 15A is a perspective view of the liquid discharge head 3 in which the lead wiring is formed. The lead wiring 49 b is routed from the second end face 48 of the liquid discharge head 3 to the upper end face 50 of the liquid discharge head 3. In a process described later, a portion of the lead wiring 49b formed on the upper end surface 50 is connected to the third flexible substrate 11 (see FIGS. 1 and 2).

  The electrode patterning of the second end face 48 can be formed by the same method as the electrode patterning of the first end face 47.

  FIG. 15B shows an electrode pattern on the F-F ′ cross section in FIG. The lead wiring 49b is electrically connected to the second electrode portion 21b in the air chamber 7, but is not connected to the first electrode (SIG) 20 in the individual liquid chamber 6.

  As a method of forming the lead-out wiring 49b, for example, a method of forming a Cr film with a thickness of about 20 nm as a base layer and a film of Au with a thickness of about 1000 nm as an electrode layer can be cited. Alternatively, Cr is deposited to a thickness of approximately 20 nm as the underlayer, Pd is deposited to a thickness of approximately 50 nm on the Cr film, Ni plating is performed to a thickness of approximately 1000 nm using the Pd film as a seed layer, and only the surface of the Ni film is replaced with Au. Also, the metal film can be formed.

  Note that the metal film forming method mentioned in the latter is thinner because the film thickness at the time of lift-off is small, so that burrs are less likely to remain, and the patterning property is improved.

  Between each piezoelectric substrate 12, 32, 45, and 46, there is a gap of about 1 to 2 μm due to the adhesive layer. However, if the lead wiring 49b has a thickness of 1000 nm, the lead wiring 49b is not divided by the gap.

(Formation of individual electrodes on the second end face)
Next, a lead-out wiring from the first electrode (SIG) 20 provided in each individual liquid chamber 6 is formed on the second end surface 48 of the liquid discharge head 3. FIG. 16A shows a perspective view of the liquid discharge head 3 in which the lead-out wiring 52 from the first electrode (SIG) 20 is formed, and FIG. 16B shows an enlargement of the G part in FIG. The figure is shown. The lead wiring 52 is formed on the second end surface 48 of the liquid ejection head 3.

  The electrode patterning of the second end face 48 can be formed by the same method as the electrode patterning of the first end face 47. In this embodiment, the lead-out wiring 52 is formed after the lead-out wiring 49b is formed on the second end face. However, the lead-out wiring 49b and the lead-out wiring 52 may be formed simultaneously.

  FIG. 17 shows an electrode pattern on the H-H ′ cross section in FIG. By forming the lead wiring 52 on the inner surface of the individual liquid chamber 6 and the opening edge of the individual liquid chamber 6, the first and fifth electrodes (SIG) 20, 41 in the individual liquid chamber 6 are electrically connected. The

(Wiring board adhesion and wiring connection)
Next, adhesion of the wiring board to the second end face 48 of the liquid discharge head 3 will be described with reference to FIGS. 18 is an exploded perspective view showing the positional relationship between the wiring board and the liquid ejection head 3, and FIG. 19 is a cross-sectional view taken along the line II ′ shown in FIG.

  As shown in FIGS. 18 and 19, the wiring board 53 has a through hole (through pole) 54 that penetrates the wiring board 53 at a position corresponding to each individual liquid chamber 6, and a mounting wiring 55. A Si substrate can be used as the wiring substrate 53. The through hole 54 is formed by etching, and the mounting wiring 55 is formed by photolithography and film formation.

  The opening of the through hole 54 is larger than the opening of the individual liquid chamber 6. For example, when the cross section of the individual liquid chamber 6 is a square of 120 μm × 120 μm, the diameter of the through hole 54 can be about 150 μm. The thickness of the wiring board 53 is, for example, about 200 μm.

  In addition, when the wiring substrate 53 is attached to the liquid ejection head 3, an insulating film is formed on the surface of the wiring substrate 53 by thermal oxidation or the like in order to prevent a short circuit of the wiring formed on the liquid ejection head 3. It is preferable.

  For the bonding, for example, an epoxy adhesive can be used. When using an adhesive, the through hole 54 and the individual liquid chamber 6 of the wiring board 53 may be filled with the adhesive. In order to prevent such a situation, it is desirable to appropriately control the amount of the adhesive when applying the adhesive to the wiring substrate 53 and the liquid ejection head 3.

  As a method for applying the adhesive, a thin uniform adhesive layer is formed on a separately prepared flat substrate by spin coating or screen printing, and the wiring substrate 53 is pressed against the adhesive layer to form the adhesive layer. A method of transferring to the wiring board 53 is exemplified. According to this method, a thin and uniform adhesive layer can be formed on the wiring board 53.

  After applying the adhesive, the wiring substrate 53 is positioned in a state where there is a minute gap between the wiring substrate 53 and the liquid ejection head 3, and the wiring 52 is pressure bonded to the liquid ejection head 3. As a measure of the thickness of the adhesive, it is appropriate that the thickness of the adhesive layer before bonding is about 4 μm and the thickness after bonding is about 2 μm.

  The first and second bonding alignment grooves 18 and 38 (see FIGS. 4 and 7) formed during the groove processing on the first and second piezoelectric substrates 12 and 32 are the second end face 48 of the liquid discharge head 3. It is confirmed from. The wiring board 53 is provided with a wiring board alignment hole 56 for confirming the first and second bonding alignment grooves 18 and 38. Therefore, when the wiring board 53 is bonded to the liquid ejection head 3, the wiring board 53 can be positioned using the first and second bonding alignments and the wiring board alignment hole 56.

  After joining the liquid ejection head 3 and the wiring board 53, the lead-out wiring 52 formed on the second end surface 48 of the liquid ejection head 3 and the mounting wiring 55 formed on the wiring board 53 are connected by the lead-out wiring 57. . The electrode patterning of the lead wiring 57 can be formed by the same method as the electrode patterning of the first end face 47.

  The lead wiring 52 is connected to the mounting wiring 55 through a lead wiring 57 formed on the inner surface of the through hole 54. The mounting wiring 55 is connected to a mounting wiring connecting portion (SIG) 58, and the lead wiring 52 is connected to the first flexible substrate 9 (see FIG. 2).

(Back diaphragm plate adhesion)
Next, the rear diaphragm plate 4 will be described with reference to FIGS. FIG. 20 is a top view and a side sectional view of a portion of the rear throttle plate 4 corresponding to the individual liquid chamber 6. The rear throttle plate 4 is provided with through holes (rear throttles) 59 at positions corresponding to the individual liquid chambers 6.

  The through hole (rear restrictor) 59 restricts the back flow of ink so that the ink flow generated by driving the wall of the individual liquid chamber 6 (see FIG. 2 and the like) is strongly generated on the ejection port 8 side. The rear aperture plate 4 can be formed by etching the Si substrate.

  The through hole 59 is smaller than the opening of the individual liquid chamber 6. For example, when the opening of the individual liquid chamber 6 is a square of 120 μm × 120 μm, the diameter of the through hole 59 can be about 50 μm. The thickness of the rear diaphragm plate 4 can be about 200 μm, for example.

  In addition, an insulating film is formed on the surface of the rear diaphragm plate 4 by thermal oxidation or the like in order to prevent a short circuit of the wiring formed on the liquid ejection head 3 when the rear diaphragm plate 4 is attached to the liquid ejection head 3. It is preferable to keep it.

  For the adhesion, for example, an epoxy adhesive can be used. When an adhesive is used, the through hole 59 of the rear diaphragm plate 4, the through hole 54 (see FIG. 18) of the wiring board 53, and the individual liquid chamber 6 (see FIG. 2) may be filled with the adhesive. In order to prevent such a situation, it is desirable to appropriately control the amount of the adhesive when applying the adhesive to the rear diaphragm plate 4 or the wiring board 53.

  As a method for applying the adhesive, a thin uniform adhesive layer is formed on a separately prepared flat substrate by spin coating or screen printing, and the rear diaphragm plate 4 is pressed against the adhesive layer to form an adhesive layer. Is transferred to the rear diaphragm plate 4. According to this method, a thin and uniform adhesive layer can be formed on the rear diaphragm plate 4.

  After applying the adhesive, the rear diaphragm plate 4 is positioned in a state where there is a minute gap between the rear diaphragm plate 4 and the wiring board 53, and the rear diaphragm plate 4 is pressure bonded to the wiring board 53. As a measure of the thickness of the adhesive, it is appropriate that the thickness of the adhesive layer before bonding is about 4 μm and the thickness after bonding is about 2 μm.

  Further, in order to reduce the protrusion of the adhesive to the through hole 54 of the wiring board 53 and the individual liquid chamber 6 and the air chamber 7, a groove 60 is formed outside the through hole 59 of the rear diaphragm plate 4 as shown in FIG. It is also effective to form and use as an adhesive relief groove.

  FIG. 21 is a diagram showing the positional relationship when the rear diaphragm plate 4 and the orifice plate 2 are joined to the liquid discharge head 3 to which the wiring board 53 is joined. As shown in FIG. 21, the rear diaphragm plate 4 is provided with a rear diaphragm plate alignment hole 61 for positioning with the alignment grooves 18 and 38 for bonding.

  The first and second bonding alignment grooves 18 and 38 (see FIGS. 4 and 7) formed when the grooves are formed in the first and second piezoelectric substrates 12 and 32 are formed in the wiring substrate alignment hole 56 of the wiring substrate 53. Appears in Therefore, when the rear diaphragm plate 4 is bonded to the liquid ejection head 3, the rear diaphragm plate 4 can be positioned using the first and second bonding alignments and the rear diaphragm plate alignment hole 61.

  Further, the rear diaphragm plate 4 is bonded to the wiring board 53 so that the mounting wiring connecting portion (SIG) 58 is exposed.

(Insulation treatment)
Next, first and fifth electrodes (SIG) 20, 41 formed on the inner surface of the individual liquid chamber 6, and second, third, and fourth electrodes (GRN) formed on the inner surface of the air chamber 7. ) An insulating film is formed on the surfaces of 21, 25, 39 and the electrode wiring. However, an insulating film is not formed on portions of the electrode wiring that are connected to the first, second, and third flexible substrates 9, 10, and 11. Therefore, a mask such as a tape is applied to the portion during film formation.

  The insulating film is, for example, a parylene thin film, and the insulating film is formed by a chemical vapor deposition (CVD) method. In particular, it is preferable to use parylene (N) having excellent throwing power in order to form an insulating film up to the inner wall of the liquid chamber. An appropriate thickness of the insulating film is about 5 μm.

  In order to improve the adhesion of parylene, UV ozone treatment is preferably performed at room temperature for about 5 minutes before film formation. Further, a coupling agent may be applied after the UV ozone treatment in order to improve the adhesion.

  In particular, when Au is used for the GND electrode of the first end face 47 of the liquid discharge head 3, the surface treatment with a triazine thiol-based coupling agent is effective because the adhesion to parylene is extremely low. . Further, when a Si substrate is used for the rear diaphragm plate 4 and an oxide film is formed on the surface, a silane coupling agent is effective. The coupling treatment can be performed by thinly applying a coupling agent diluted with IPA and then drying it in an oven.

(Orifice plate adhesion)
Next, the orifice plate 2 is bonded to the first end face 47 of the liquid ejection head 3. FIG. 22 shows a plan view and a side sectional view of a portion of the orifice plate 2 corresponding to each individual liquid chamber 6.

  The orifice plate 2 is a plate in which through holes (discharge ports 8) are formed at positions corresponding to the individual liquid chambers 6 of the liquid discharge head 3. As an example, the discharge port 8 is a circular hole having a diameter of 10 μm and a depth of 20 μm. A relief groove 62 is provided on the surface of the orifice plate 2 on the side to be joined to the liquid ejection head 3 so that the adhesive does not block the ejection port 8.

  The escape groove 62 is preferably smaller than the opening of the individual liquid chamber 6 in order to prevent bubbles from staying in the ink. For example, the escape groove 62 may be a hole having a diameter of 80 μm and a depth of 60 μm. In this case, the thickness of the orifice plate 2 is 80 μm.

  An example of a method for producing such an orifice plate 2 is Ni electroforming. Further, ink repellent treatment is performed on the surface of the orifice plate 2 that is not in contact with the first end surface 47. As the ink repellent material, there are silane-based and fluorine-based materials, which can be coated by vapor deposition or the like.

  The orifice plate 2 is joined to the liquid ejection head 3 using, for example, an adhesive. For the adhesion, for example, an epoxy adhesive can be used.

  When an adhesive is used, the discharge port 8 and the individual liquid chamber 6 of the orifice plate 2 may be filled with the adhesive. In order to prevent such a situation, it is desirable to appropriately control the amount of the adhesive when applying the adhesive to the orifice plate 2.

  As a method for applying the adhesive, a thin uniform adhesive layer is formed on a separately prepared flat substrate by spin coating or screen printing, and the orifice plate 2 is pressed against the adhesive layer to form the adhesive layer. A method of transferring to the orifice plate 2 is exemplified. According to this method, a thin and uniform adhesive layer can be formed on the orifice plate 2.

  After applying the adhesive, the orifice plate 2 is positioned in a state where there is a minute gap between the orifice plate 2 and the liquid discharge head 3, and the orifice plate 2 is pressure-bonded to the liquid discharge head 3. As a measure of the thickness of the adhesive, it is appropriate that the thickness of the adhesive layer before bonding is about 4 μm and the thickness after bonding is about 2 μm.

  The first and second bonding alignment grooves 18 and 38 (see FIGS. 4 and 7) formed when the grooves are formed in the first and second piezoelectric substrates 12 and 32 are formed on the first end face 47 of the liquid ejection head 3. It is appearing in. The orifice plate 2 is provided with an orifice plate alignment hole 63 for confirming the first and second bonding alignment grooves 18 and 38. Therefore, when the orifice plate 2 is bonded to the liquid ejection head 3, the orifice plate 2 can be positioned using the first and second bonding alignment grooves 18 and 38 and the wiring board alignment hole 56.

(Wiring mounting)
Next, the first, second, and third flexible substrates 9, 10, and 11 are pressure-bonded to the wiring electrodes. As shown in FIG. 23, the first, second, and third flexible substrates 9, 10, and 11 are pressure-bonded to the SIG electrode on the second end surface 48 and the GND wiring on the upper end surface 50. An anisotropic conductive film (ACF; anisotropic conductive film) is used for pressure bonding. As the pressure bonding conditions, 150 ° C., 3 MPa, and about 10 seconds are appropriate. After crimping, the vicinity of the joint with the FPC is reinforced with an adhesive.

(Common liquid chamber adhesion)
After that, as shown in FIGS. 1 and 2, the common liquid chamber 5 having the ink supply port 64 is prepared, and the common liquid chamber 5 is joined to the rear diaphragm plate 4. For example, the common liquid chamber 5 is formed by machining a SUS substrate and bonded to the rear diaphragm plate 4 using an adhesive.

  Finally, other necessary parts are further assembled to complete the liquid discharge head unit 1.

(Drive)
The operation of the liquid discharge head 3 will be described with reference to FIG. FIG. 24 is an enlarged cross-sectional view of a region J in FIG. As shown in FIG. 24A, the individual liquid chambers 6 are formed in a two-dimensional array. An air chamber 7 is formed between the adjacent individual liquid chambers 6. The partition walls defining the individual liquid chamber 6 are polarized in the outward direction 65 of the individual liquid chamber 6.

  The first and fifth electrodes (SIG) 20 and 41 formed on the inner surface of the individual liquid chamber 6 are individually connected to one electrode wiring. The second, third and fourth electrodes (GND) 21, 25, 39 formed on the outer surface of each individual liquid chamber 6 are respectively connected on the first end surface 47 side and the second end surface 48 side. Are connected to a common electrode wiring. By applying drive signals to the individually connected wires, the walls of the individual liquid chambers 6 operate independently at the first end surface 47 side portion and the second end surface 48 side portion, respectively. .

  FIG. 24B highlights the state of the liquid ejection head 3 when a driving voltage is applied. Second, third and fourth electrodes formed on the outer surface of the individual liquid chamber 6 with the first and fifth electrodes (SIG) 20 and 41 formed on the inner surface of the individual liquid chamber 6 at a positive potential. (GND) 20, 25, 39 are set to the GND potential, and a voltage is applied between the electrodes.

  Accordingly, the partition wall forming the individual liquid chamber 6 is deformed so as to contract the individual liquid chamber 6. By this deformation, the pressure of the ink filled in the individual liquid chamber 6 is increased, and droplets are ejected from the ejection port 8 (see FIGS. 1 and 2).

  On the other hand, when the first and fifth electrodes 20 and 41 are set to the GND potential and the second, third and fourth electrodes 21, 25 and 39 are set to the positive potential and the drive voltage is applied, the partition walls are expanded so that the individual liquid chambers expand. Is deformed (not shown).

  As shown in FIG. 11, in this embodiment, the individual liquid chamber 6 is formed by stacking the first piezoelectric substrate 12 in which the first groove 14 is formed and the second piezoelectric substrate 32. 6 is formed. Therefore, the individual liquid chamber 6 having a relatively high accuracy and a deeper depth can be formed as compared with the case where the through hole is formed in the piezoelectric member to form the individual liquid chamber 6.

  The air chamber 7 is formed by stacking the first piezoelectric substrate 12 in which the second groove 19 is formed and the second piezoelectric substrate 32 in which the third groove 34 is formed. The Therefore, compared with the case where the groove is formed in the depth direction of the individual liquid chamber 6 to form the air chamber 7, the rigidity of the wall of the individual liquid chamber 6 is less likely to decrease, and the depth direction of the wall of the individual liquid chamber 6 is related. The dimensions can be made larger. As a result, the double actuator type liquid discharge head 3 can be manufactured relatively easily.

  Furthermore, in this embodiment, as shown in FIGS. 5, 6, 8 and 9, a voltage is applied between the first electrode (SIG) 20 and the second and third electrodes (GND) 21 and 25. By applying the voltage, the first piezoelectric substrate 12 is polarized. The second piezoelectric substrate 12 is polarized by applying a voltage between the fifth electrode (SIG) 41 and the fourth electrode (GND) 39.

  Thereafter, by separating the second, third and fourth electrodes (GND) 21, 25, 39, a plurality of electrodes arranged in the depth direction of the individual liquid chamber 6 (see FIG. 11) are formed. That is, a plurality of piezoelectric elements arranged in the depth direction of the individual liquid chamber 6 can be manufactured in the same process, and the manufacturing period of the liquid discharge head 3 can be shortened.

  In addition, a plurality of piezoelectric elements arranged in the depth direction of the individual liquid chamber 6 (see FIG. 11) are provided with second, third and fourth electrodes (GND) 21 provided on the outer surface of the individual liquid chamber 6, 25, 39 are separated. That is, a plurality of piezoelectric elements arranged in the depth direction of the individual liquid chamber 6 can be formed as a single-layer piezoelectric element. Therefore, it is not necessary to form through holes necessary for manufacturing the multilayer piezoelectric element in the present embodiment, and the liquid discharge head 3 can be manufactured by simpler processing.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 25 is a perspective view showing the appearance of the liquid discharge head 3 manufactured by using the manufacturing method according to the present embodiment. 26 is a cross-sectional view taken along the line KK ′ in FIG.

  As shown in FIGS. 25 and 26, in this embodiment, a bumped wiring board 66 is used. The bumped wiring board 66 includes a bump electrode 67, a lead wiring 68, a through hole 69, and a mounting wiring 70.

  The through hole 69 is formed at a position corresponding to each individual liquid chamber 6 of the bumped wiring board 66. The bump electrode 67 is formed at the edge of one opening of the through hole 69. The lead-out wiring 68 is formed from the bump electrode 67 through the through hole 69 to the edge of the other opening of the through hole 69. The lead-out wiring 68 formed at the edge of the other opening of the through hole 69 is connected to the mounting wiring connecting portion (SIG) 71 via the mounting wiring 70.

  The lead wiring 52 and the bump electrode 67 are bump-bonded by a technique such as thermocompression bonding or ultrasonic bonding. As the material and shape of the bump, for example, a gold bump having a diameter of 40 μm and a height of 40 μm can be used.

  Sealing is performed with a sealant 72 so as not to leak between the bumped wiring board 66 and the liquid discharge head 3. For example, a silicone-based sealant can be used as the sealant 72. Processes before and after the bonding with the bump wiring are performed in the same manner as in the first embodiment.

  The opening of the through hole 69 is preferably smaller than the opening of the individual liquid chamber 6. For example, when the opening of the individual liquid chamber 6 is a square of 120 μm × 120 μm, it is preferable that the opening of the through hole 69 has a diameter of about 50 μm. The depth of the through hole 69 is preferably about 200 μm. The through hole 69 restricts the back flow of ink so that the ink flow generated by driving the liquid discharge head 3 is strongly generated on the discharge port 8 side.

  The wiring board 66 with bumps can be formed by etching the Si substrate, photolithography process, bump processing, and the like. Since the bumped wiring board 66 also serves as the rear diaphragm plate 4 (see FIGS. 1 and 2), the yield is improved.

(Third embodiment)
Next, a third embodiment of the present invention will be described. The present embodiment relates to a method for manufacturing a large number of liquid ejection heads 3 from a single piezoelectric substrate. The steps other than the electrode separation step and the chip separation step are the same as those in the first embodiment (not shown).

  For example, a case where three liquid ejection heads 3 are manufactured from the first and second piezoelectric substrates 12 and 32 shown in FIGS. 4 and 7 using the manufacturing method of the present embodiment will be described.

  In the electrode separation process, the second, third and fourth electrodes (GNS) 21, 25, 39 (starting from a position 2 mm from the second chip separation position 30, 44 (see FIGS. 5 and 8) at a pitch of 3 mm are provided. 6 and 9). Then, in the chip separation step, the chip size is set to 10 mm × 3 mm, and the first and second piezoelectric substrates 12 and 32 shown in FIGS. 4 and 7 are each separated into 15 chips.

  According to this embodiment, a large number of liquid ejection heads 3 can be easily obtained, and the manufacturing cost of the liquid ejection head 3 can be suppressed.

3 Liquid discharge head 6 Individual liquid chamber 7 Air chamber 8 Discharge port 12 First piezoelectric substrate 14 First groove 15 Groove forming surface 19 Second groove 20 First electrode (SIG)
21 Second electrode (GND)
23 Surface 25 Third electrode (GND)
32 Second piezoelectric substrate 34 Third groove 35 Groove forming surface 39 Fourth electrode (GND)
40 surface 41 5th electrode (SIG)

Claims (3)

A plurality of individual liquid chambers partitioned by a wall of piezoelectric material and communicating with a discharge port for discharging liquid; a recess disposed around the individual liquid chamber and separating the walls of the adjacent individual liquid chambers; and the individual liquid A liquid discharge head manufacturing method comprising: an inner electrode disposed on an inner surface of a chamber; and a plurality of outer electrodes disposed on an outer surface of the individual liquid chamber and arranged in a depth direction of the individual liquid chamber. ,
A preparation step of preparing the first and second piezoelectric substrates;
A plurality of first grooves extending in parallel with each other are formed on the first surface A1 of the first piezoelectric substrate, and the second grooves extending in parallel with the first grooves are adjacent to the first grooves. Forming a plurality of third grooves extending in parallel with each other on the first surface B1 of the second piezoelectric substrate; and
The first electrode is formed on the side surface and the bottom surface of the first groove, the second electrode is formed on the side surface of the second groove, and the first surface A1 of the first piezoelectric substrate is defined as A third electrode is formed on the second surface A2 on the opposite side, a fourth electrode is formed on the bottom surface of the third groove, and is opposite to the first surface B1 of the second piezoelectric substrate. An electrode forming step of forming a fifth electrode on the second surface B2 on the side;
A voltage is applied between the first electrode and the second and third electrodes to polarize a side wall and a bottom wall of the first groove, and the fourth electrode and the fifth electrode A polarization step of applying a voltage to the electrode to polarize the bottom wall of the third groove;
A plurality of the second and third electrodes are separated into at least two in the direction in which the first groove extends, and the fourth electrode is separated into at least two in the direction in which the third groove extends. An electrode separation step;
The first surface A1 of the first piezoelectric substrate and the second surface B2 of the second piezoelectric substrate in a state where the position of the first groove and the position of the third groove are matched. By joining, the first groove is the individual liquid chamber, the second and third grooves are the recesses, the first and fifth electrodes are the inner electrodes, and the second and third And a laminating step using the fourth electrode as the outer electrode. In the preparation step, further preparing a wiring board on which wiring is formed corresponding to the individual liquid chamber,
Forming a wiring connected to the inner electrode by bonding the wiring board to a surface of the laminate formed by laminating the first and second piezoelectric substrates and having an opening of the individual liquid chamber. The method of manufacturing a liquid ejection head according to claim 1, which is included after the step.   The method of manufacturing a liquid ejection head according to claim 2, wherein the wiring board has a bump electrode on a surface of the wiring board on a side bonded to the stacked body.

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