JP2015118990A - Actuator substrate manufacturing method, actuator substrate, liquid cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an actuator substrate capable of manufacturing a reliable actuator substrate, preventing peeling and rising of a base material electrode of a connection hole bottom part that have occurred at the time of resist removable during a connection hole formation step.SOLUTION: An actuator substrate is manufactured which includes a piezoelectric body that is sandwiched between an upper electrode and a lower electrode 10, and a wiring connected to the upper electrode through a connection hole 30. In a method of forming the connection hole 30 by removing a resist pattern 46, an insulation film 47 that prevents exposure of the upper electrode is temporarily left out.

Description

  The present invention relates to a method for manufacturing an actuator substrate.

  A piezoelectric element using PZT is formed on an actuator substrate employed in a thin film PZT head, and Pt having a high melting point and a stable melting point is used as an electrode. The electrode layer is formed with a metal oxide film (for example, SRO, LNO) between the Pt electrode and the PZT layer for the purpose of preventing the PZT characteristic deterioration. Pt is a chemically stable substance, but is known for its large catalytic action. In the process of forming the actuator substrate, a contact hole is formed in the interlayer insulating film on the upper electrode or on the lower electrode, which is a common electrode, in order to apply a driving pulse to the upper electrode from the outside, and the lead wiring pattern and the contact hole are formed. Through electrical contact. This contact hole is formed by etching the resist pattern as a mask. After the etching is completed, Pt having a large catalytic action is exposed at the bottom of the contact hole.

  In “Patent Document 1”, the adhesion between the adhesion layer and the upper layer deteriorates due to the corrosion caused by the contact between different metals between the adhesion layer and the upper layer at the time of patterning the upper layer made of Au, and the upper layer peels off. In order to prevent the problem of facilitating, the lead-out wiring is composed of an adhesion layer made of titanium / tungsten alloy and an upper layer made of Au, so that when the upper layer of the lead-out wiring is patterned by wet etching, the adhesion layer and the upper layer A technique for improving the adhesion of the lead-out wiring without causing corrosion is disclosed.

  As a method of removing the resist pattern after the etching is completed, a method of decomposing (carbonizing) the resist by oxygen plasma treatment or UV irradiation is generally known. However, in such a method, hydrogen (atom, radical, ion) is generated in the plasma. This hydrogen is activated by the catalytic action of Pt exposed at the bottom of the contact hole, passes through Pt, reduces the underlying metal oxide film or PZT, and causes a reaction to extract the oxygen. As a result, when the metal oxide film is reduced, peeling occurs at the interface between Pt and the metal oxide film, and the PZT is deteriorated by reducing PZT. Therefore, such an actuator substrate cannot sufficiently obtain its characteristics, has poor quality and has a problem in driving durability, and thus cannot provide sufficient characteristics. Therefore, the actuator provided with this piezoelectric element does not provide sufficient driving durability, and the droplet discharge head provided with this actuator does not stabilize the desired droplet discharge characteristics, and can ensure higher reliability. There is a problem that it is not possible.

  Further, the technique disclosed in “Patent Document 1” has a problem in that the device characteristics are sacrificed because the material selection of the electrode layer is restricted and the device characteristics cannot be prioritized.

  The present invention solves the above-mentioned problems, prevents the base electrode from peeling off and floating at the bottom of the connection hole, which has occurred at the time of removing the resist in the connection hole forming step, and provides a highly reliable actuator substrate that can be manufactured. The purpose is to provide a manufacturing method.

  The invention according to claim 1 is a method of manufacturing an actuator substrate having a piezoelectric body sandwiched between an upper electrode and a lower electrode, and wiring connected to the upper electrode through a connection hole, An insulating film that prevents the upper electrode from being exposed is temporarily left when the connection hole is formed by removing the insulating film.

  According to the present invention, it is possible to prevent the occurrence of film floating or film peeling of the upper electrode layer or the lower electrode layer at the bottom of the connection hole, which has conventionally occurred, and form an actuator substrate with high reliability and high yield. be able to.

It is the schematic explaining one Embodiment of this invention. It is a schematic sectional drawing of the droplet discharge head to which the 1st Embodiment of this invention is applied. It is the schematic explaining the manufacturing process of the droplet discharge head to which the 1st Embodiment of this invention is applied. It is the schematic explaining the manufacturing process of the droplet discharge head to which the 1st Embodiment of this invention is applied. It is the schematic explaining the manufacturing process of the droplet discharge head to which the 1st Embodiment of this invention is applied. It is the schematic explaining the manufacturing process of the droplet discharge head to which the 1st Embodiment of this invention is applied. It is the schematic explaining the manufacturing process of the droplet discharge head to which the 1st Embodiment of this invention is applied. It is the schematic explaining the manufacturing process of the droplet discharge head to which the 1st Embodiment of this invention is applied. It is the schematic explaining the manufacturing process of the droplet discharge head to which the 1st Embodiment of this invention is applied. It is the schematic explaining the manufacturing process of the droplet discharge head to which the 2nd Embodiment of this invention is applied. It is the schematic explaining the manufacturing process of the droplet discharge head to which the 2nd Embodiment of this invention is applied. It is the schematic explaining the manufacturing process of the droplet discharge head to which the 2nd Embodiment of this invention is applied. It is the schematic explaining the manufacturing process of the droplet discharge head to which the 2nd Embodiment of this invention is applied. It is a schematic perspective view of the ink cartridge used for the 3rd Embodiment of this invention. It is a schematic perspective view of the inkjet recording device used for the 4th Embodiment of this invention. It is a schematic front view of the inkjet recording device used for the 4th Embodiment of this invention.

  FIG. 1 is a perspective view of a droplet discharge head having a piezoelectric actuator used in the first embodiment of the present invention, and FIG. 2 is a sectional view in the longitudinal direction of the liquid chamber in FIG. In the figure, a droplet discharge head 1 is of a side shooter type that discharges droplets from nozzle holes provided on one surface of a substrate. The droplet discharge head 1 includes a piezoelectric liquid element 2 that generates liquid droplet discharge energy, a pressurized liquid chamber partition wall 4 that includes a vibration plate 3, and a plurality of pressure liquid chamber partition walls 4 partitioned on the first substrate 100. The pressurized liquid chamber 5, the fluid resistance portion 7, and the common liquid chamber 8 are formed.

  The first substrate 100 is provided with a diaphragm 3 that constitutes a partial wall surface of the pressurized liquid chamber 5 and is a plate that vibrates when the piezoelectric element 2 is driven. A piezoelectric element 2 is provided at a portion facing the liquid chamber 5. A common flow path 9 is formed in the common liquid chamber 8, and ink that is liquid droplets can be supplied from the outside through the common flow path 9. The piezoelectric element 2 includes a common electrode 10 that is a lower electrode, an individual electrode 11 that is an upper electrode, and a piezoelectric body 12, and the piezoelectric body 12 is sandwiched between the common electrode 10 and the individual electrode 11.

  The second substrate 200 disposed above the first substrate 100 allows the supply port 66 for supplying droplets from the outside, the common flow path 9 that is a liquid flow path, and the bending of the diaphragm 3. A recess 67 is formed. In addition, nozzle holes 6 are formed at positions corresponding to the individual pressurized liquid chambers 5 in the nozzle substrate 300 disposed below the first substrate 100. An interlayer insulating film 45 is formed above the common electrode 10, a wiring 40 is formed above the common electrode 10, and a passivation film 50 is formed above the common electrode 10 for the purpose of protecting the wiring 40.

  In the above configuration, the droplet discharge head 1 is configured by bonding the actuator substrate 20, the second substrate 200, and the nozzle substrate 300. The actuator substrate 20 is configured by the first substrate 100, the piezoelectric element 2, the diaphragm 3, the common electrode 10, the interlayer insulating film 45, and the wiring 40. In addition, the wiring 40 and the individual electrode 11 are connected to each other through a connection hole 30 formed in the interlayer insulating film 45.

  In the droplet discharge head 1 configured as described above, image data is sent from a control unit (not shown) in a state where each pressurizing liquid chamber 5 is filled with a recording liquid such as an ink. Then, based on the sent image data, the individual electrodes 11 corresponding to the nozzle holes 6 on which the recording liquid is to be discharged are connected via the connection holes 30 formed in the wiring 40 and the interlayer insulating film 45 by the oscillation circuit. For example, a pulse voltage of 20V is applied. By applying the pulse voltage, the piezoelectric body 12 itself contracts in a direction parallel to the diaphragm 3 due to electrostriction, and the diaphragm 3 bends in the direction of the pressurized liquid chamber 5. As a result, the pressure in the pressurizing liquid chamber 5 rapidly increases, and the recording liquid is discharged from the nozzle hole 6 communicating with the pressurizing liquid chamber 5.

  After applying the pulse voltage, since the contracted piezoelectric body 12 is restored, the deflected diaphragm 3 returns to its original position, so that the pressurized liquid chamber 5 has a negative pressure compared to the common liquid chamber 8. . As a result, the ink supplied from the outside through the supply port 66 is supplied from the common flow path 9 and the common liquid chamber 8 to the pressurized liquid chamber 5 through the fluid resistance portion 7. By repeating this, the droplets can be ejected continuously, and an image can be formed on a recording medium (for example, paper) disposed facing the droplet ejection head 1.

  Next, the manufacturing process of the droplet discharge head 1 according to the first embodiment of the present invention will be sequentially described. First, as shown in FIG. 3, the diaphragm 3 is formed as a first substrate 100 on a silicon single crystal substrate having a surface orientation <110> (for example, a plate thickness of 400 μm). The diaphragm 3 may be a single layer film or a laminated film as long as the function as the diaphragm and subsequent process consistency are ensured. For example, as a material of the diaphragm 3, a silicon oxide film, a polysilicon film, an amorphous silicon film, or a silicon nitride film is formed in a laminated structure so as to have a desired diaphragm rigidity by LP-CVD. In view of process consistency, diaphragm rigidity, and overall stress of diaphragm 3, the number of stacked layers is preferably about 3 to 7 layers. Further, in order to ensure adhesion with the later common electrode 10, the uppermost layer of the diaphragm 3 is a silicon oxide film formed by the LP-CDV method.

Next, as shown in FIG. 4, a common electrode 10 made of TiO ₂ and Pt is formed by sputtering to a thickness of 50 nm and 100 nm, respectively. Next, PZT is formed as the piezoelectric body 12 on the common electrode 10 in a plurality of times, for example, by spin coating, and is finally formed to a thickness of 2 μm. Next, the individual electrode 11 on Pt is formed with a thickness of, for example, 100 nm by sputtering. Here, the film forming method of the piezoelectric body 12 is not limited to the spin coating method, and may be formed by, for example, a sputtering method, an ion plating method, an air sol method, a sol gel method, an ink jet method, or the like. Then, the individual electrode 11 and the piezoelectric body 12 are patterned by the litho-etching method in order to form the piezoelectric element 2 at a position corresponding to the pressurized liquid chamber 5 to be formed later. Thereafter, the common electrode 10 is patterned by a lithographic etching method. At this time, the layer of the common electrode 10 at a location that will later become the common flow path 9 is also patterned.

Next, as shown in FIG. 5, an interlayer insulating film 45 is formed to insulate the common electrode 10, the piezoelectric body 12, and the wiring 40 to be formed later. As the interlayer insulating film 45, a SiO ₂ film is formed by, for example, a plasma CVD method. The interlayer insulating film 45 is not limited to the SiO ₂ film formed by the plasma CVD method as long as it has an insulating property without affecting the piezoelectric body 12 and the electrode material.

  Next, as shown in FIG. 6, a resist pattern 46 is formed in order to form the connection hole 30 for connecting the individual electrode 11 and the wiring 40 by a lithographic etching method. Although not shown here, when the common electrode 10 is also connected to the wiring 40, a connection hole is similarly formed. Next, as shown in FIG. 7, the interlayer insulating film 45 in the connection hole 30 is removed by etching using the resist pattern 46 as a mask. At this time, the interlayer insulating film 45 is thin so that the individual electrode 11 is not exposed. An insulating film 47 is formed, and this is left, for example, about 50 nm. Next, as shown in FIG. 8, the resist pattern 46 is completely removed by an oxygen plasma method, and thereafter, the thin insulating film 47 left in the connection hole 30 is completely removed as shown in FIG. Examples of means for removing the insulating film 47 include an Ar sputtering method and a CF4 plasma method.

  Through the above-described steps, it is possible to prevent the occurrence of film floating or film peeling of the individual electrode 11 layer or the common electrode 10 layer at the bottom of the connection hole 30 which has been generated conventionally, and the actuator substrate 20 has high reliability and high yield. Can be formed. The droplet discharge head 1 using the actuator substrate 20 can obtain stable characteristics and has high reliability. Furthermore, the present invention can also be applied to a liquid cartridge in which the droplet discharge head 1 is integrated or an image forming apparatus equipped with the droplet discharge head 1. This example will be described later.

  Next, a manufacturing process of the droplet discharge head 1 according to the second embodiment of the present invention will be described. In the second embodiment, a film-like member 48 having an etching rate slower than that of the interlayer insulating film 45 is formed in the lower layer of the interlayer insulating film 45 in the etching when the connection hole 30 is formed, and the individual electrode 11 is etched when the connection hole 30 is etched. Is configured not to be exposed. Although described below with reference to the drawings, the processes up to the step of patterning the individual electrode 11, the piezoelectric body 12, and the common electrode 10 by the lithoetch method are the same as those in the first embodiment.

First, as shown in FIG. 10, after patterning the individual electrode 11, the piezoelectric body 12, and the common electrode 10, a film-like member 48 whose etching rate is slower than that of the interlayer insulating film 45 in the etching at the time of forming the connection hole 30 is 50 nm thick, for example. About a film is formed. Here, the film-like member 48 is preferably an Al ₂ O ₃ film, a Ta ₂ O ₃ film, a TiN film, a TiO ₂ film, or the like formed by an atomic layer deposition method (ALD method). Then, an interlayer insulating film 45 is formed in the same manner as in the first embodiment, and a resist pattern 46 is formed in order to form the connection hole 30 that connects the wiring 40 and the individual electrode 11 by a lithographic etching method. Although not shown here, when the common electrode 10 is also connected to the wiring 40, a connection hole is similarly formed.

  Next, as shown in FIG. 11, the interlayer insulating film 45 in the connection hole 30 is removed by the etching method using the resist pattern 46 as a mask. At this time, the film member 48 is not etched so that the individual electrode 11 is not exposed. To leave. Due to the presence of the film-like member 48 having a slow etching rate, the individual electrode 11 at the bottom of the connection hole 30 can be reliably prevented from being exposed as compared with the first embodiment.

  Next, as shown in FIG. 12, the resist pattern 46 is completely removed by the oxygen plasma method, and then the film-like member 48 left in the connection hole 30 is completely removed as shown in FIG. Examples of the method for removing the film member 48 include an Ar sputtering method and an etching method suitable for the material.

Through the above-described steps, it is possible to more reliably prevent the occurrence of film floating or film peeling of the individual electrode 11 layer or the common electrode 10 layer at the bottom of the connection hole 30 as compared with the first embodiment, and the yield is high. High actuator substrate 20 can be formed. Further, since the film-like member 48 is formed by the atomic layer deposition method, it is possible to prevent exposure of the individual electrode 11 layer when forming the connection hole 30 with high precision and uniformity, and to realize a stable manufacturing process. be able to. Further, by using an Al ₂ O ₃ film, a Ta ₂ O ₃ film, a TiN film, or a TiO ₂ film as the film member 48, the etching rate can be reduced by 10 times or more with respect to the interlayer insulating film 45. As a result, a film thickness of about 50 nm is sufficient for the film-like member 48, the process cost can be reduced, and a highly reliable construction method can be constructed. Therefore, it is possible to provide a highly reliable actuator substrate with a high yield. .

Next, a liquid cartridge in which the above-described droplet discharge head 1 is integrated will be described as a third embodiment of the present invention.
An ink cartridge 80 as a liquid cartridge shown in FIG. 14 is obtained by integrating a droplet discharge head 1 having nozzle holes 6 and the like, and an ink tank 82 that supplies ink to the droplet discharge head 1. In such an ink cartridge 80 having the ink tank 82 and the droplet discharge head 1 integrally, the yield and reliability can be improved by increasing the accuracy, density and reliability of the actuator unit 68. it can. Thereby, cost reduction of the ink cartridge 80 can also be realized.

Next, as a fourth embodiment of the present invention, an ink jet recording apparatus as an image forming apparatus equipped with the above-described droplet discharge head 1 will be described with reference to FIGS.
An ink jet recording apparatus 90 as an image forming apparatus has a carriage 98 that is movable in the main scanning direction and in which the droplet discharge head 1 is mounted. Further, inside the apparatus main body, there are housed a droplet discharge head 1 and a printing mechanism 91 including an ink cartridge 99 that supplies ink to the droplet discharge head 1 and the like. A paper feed cassette (or a paper feed tray) 93 on which a large number of sheets 92 can be stacked from the front side is detachably attached to the lower part of the apparatus main body. Further, the apparatus main body is provided with a manual feed tray 94 that is opened when the paper 92 is manually fed. The ink jet recording apparatus 90 takes in the paper 92 fed from the paper feed cassette 93 or the manual feed tray 94, records a desired image by the printing mechanism 91, and then arranges the paper 92 after image formation on the rear side. The paper is discharged to the paper discharge tray 95.

  The printing mechanism 91 holds a main guide rod 96, a secondary guide rod 97, and a carriage 98, which are guide members spanned between left and right side plates (not shown), so as to be slidable in the main scanning direction. The carriage 98 is provided with a droplet discharge head 1 that discharges ink droplets of yellow (Y), cyan (C), magenta (M), and black (Bk). The droplet discharge head 1 is mounted with the plurality of nozzles arranged in a direction intersecting the main scanning direction with the ink droplet discharge direction facing downward.

  In addition, each ink cartridge 99 that supplies each color ink to the droplet discharge head 1 is replaceably mounted on the carriage 98. The ink cartridge 99 has an air port that communicates with the air at the top and a supply port that supplies ink to the droplet discharge head 1 at the bottom. A porous body filled with ink is provided inside the ink cartridge 99, and the ink supplied to the droplet discharge head 1 is maintained at a slight negative pressure by the capillary force of the porous body. Further, although the individual droplet discharge heads 1 are used for the respective colors, a single droplet discharge head having nozzles for discharging the ink droplets of the respective colors may be used.

  The carriage 98 is slidably fitted to the main guide rod 96 on the downstream side in the paper conveyance direction, and is slidably mounted on the secondary guide rod 97 on the upstream side in the paper conveyance direction, which is the front side. Yes. In order to move and scan the carriage 98 in the main scanning direction, a timing belt 104 is stretched between a driving pulley 102 and a driven pulley 103 that are rotationally driven by the main scanning motor 101, and the timing belt 104 is fixed to the carriage 98. . With this configuration, the carriage 98 is reciprocated by forward and reverse rotation of the main scanning motor 101.

  On the other hand, in order to convey the paper 92 set in the paper feed cassette 93 to the lower side of the droplet discharge head 1, a paper feed roller 105 and a friction pad 106 for separating and feeding the paper 92 from the paper feed cassette 93 are provided. ing. A guide member 107 that guides the paper 92 and a transport roller 108 that reverses and transports the fed paper 92 are provided. Further, a conveyance roller 109 that is pressed against the peripheral surface of the conveyance roller 108 and a leading roller 110 that defines a feeding angle of the sheet 92 from the conveyance roller 108 are provided. The transport roller 108 is rotationally driven via a gear train by a sub scanning motor (not shown).

  Corresponding to the range of movement of the carriage 98 in the main scanning direction, a printing receiving member 111 as a paper guide member is provided to guide the paper 92 sent out from the transport roller 108 at a position below the droplet discharge head 1. ing. A transport roller 112 and a spur 113 that are rotationally driven to send the paper 92 in the paper discharge direction are provided on the downstream side of the printing receiving member 111 in the paper transport direction. Further, a paper discharge roller 114 and a spur 115 for sending the paper 92 to the paper discharge tray 95, and guide members 116 and 117 for forming a paper discharge path are provided.

  In the ink jet recording apparatus 90 described above, the droplet discharge head 1 is driven according to the image signal while moving the carriage 98 during recording. Thus, ink is ejected onto the stopped sheet 92 to record one line, and then the sheet 92 is conveyed by a predetermined amount, and then the next line is recorded. Upon receiving a recording end signal or a signal that the trailing edge of the paper 92 has reached the recording area, the ink jet recording apparatus 90 ends the recording operation and discharges the paper 92.

  A recovery device 118 for recovering defective ejection of the droplet ejection head 1 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 98. The recovery device 118 includes a cap unit, a suction unit, and a cleaning unit. The carriage 98 is moved to the recovery device 118 side during printing standby, and the droplet discharge head 1 is capped by the capping unit to keep the nozzle in a wet state, thereby preventing the occurrence of ejection failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the nozzles is made constant and a stable ejection state is maintained.

  When a discharge failure occurs, the nozzle of the droplet discharge head 1 is sealed with a capping unit, and bubbles and the like are sucked out from the nozzle through the tube with a suction unit. Then, ink or dust adhered to the nozzle surface is removed by the cleaning means, and thereby the ejection failure is recovered. The sucked ink is discharged into a waste ink reservoir (not shown) provided at the lower part of the main body, and is absorbed and held by an ink absorber provided inside the waste ink reservoir.

  Since the above-described ink jet recording apparatus 90 is equipped with the droplet discharge head 1 of the present invention, stable ink discharge characteristics can be obtained and image quality can be improved. In the above description, the liquid droplet ejection head 1 ejects ink. However, the liquid droplets to which the present invention can be applied are not limited to ink. For example, the liquid droplet ejection head is used in an apparatus for ejecting a liquid resist for patterning. 1 may be applied. Further, the droplet discharge head 1 may be applied to an apparatus for discharging a gene analysis sample. The image forming apparatus to which the present invention can be applied is not limited to a printer, and the present invention can also be applied to a facsimile machine, a copying apparatus, a plotter, and a complex machine such as these.

1 Droplet ejection head 10 Lower electrode (common electrode)
11 Upper electrode (individual electrode)
12 Piezoelectric body 20 Actuator substrate 30 Connection hole 40 Wiring 45 Interlayer insulation film 46 Resist pattern 47 Insulation film 48 Film-like member 80 Liquid cartridge (ink cartridge)
90 Image forming apparatus (inkjet recording apparatus)

JP 2004-42357 A

Claims (9)

A method of manufacturing an actuator substrate having a piezoelectric body sandwiched between an upper electrode and a lower electrode, and wiring connected to the upper electrode through a connection hole,
An actuator substrate manufacturing method characterized by temporarily leaving an insulating film for preventing the upper electrode from being exposed when the resist pattern is removed to form the connection hole. In the manufacturing method of the actuator substrate according to claim 1,
The method of manufacturing an actuator substrate, wherein the insulating film is formed by an interlayer insulating film provided between the upper electrode and the resist pattern, and the insulating film is removed after removing the resist pattern. In the manufacturing method of the actuator substrate according to claim 1,
An interlayer insulating film is provided between the upper electrode and the resist pattern, and the insulating film is provided between the interlayer insulating film and the upper electrode, and the etching rate is lower than that of the interlayer insulating film. A method of manufacturing an actuator substrate, wherein the insulating film is removed after the resist pattern is formed. In the manufacturing method of the actuator substrate according to claim 3,
The method for manufacturing an actuator substrate, wherein the film-like member is formed by an atomic layer deposition method. In the manufacturing method of the actuator substrate according to claim 4,
The method for manufacturing an actuator substrate, wherein the film-like member is Al ₂ O ₃ , Ta ₂ O ₃ , TiN, or TiO ₂ .   An actuator substrate manufactured by the manufacturing method according to claim 1. In a liquid cartridge in which a droplet discharge head that discharges droplets and an ink tank that supplies a recording liquid to the droplet discharge head are integrated,
A liquid cartridge comprising the actuator substrate according to claim 6. In an image forming apparatus equipped with a droplet discharge head for discharging droplets,
An image forming apparatus, wherein the droplet discharge head includes the actuator substrate according to claim 6. In an image forming apparatus equipped with a droplet discharge head for discharging droplets,
An image forming apparatus comprising the liquid cartridge according to claim 7.

Images