JP6975394B2 - Electromechanical conversion member, liquid discharge head, liquid discharge unit, and device that discharges liquid - Google Patents

Description

The present invention relates to an electromechanical conversion member, a liquid discharge head, a liquid discharge unit, and a device for discharging a liquid.

The electromechanical conversion member of this type includes at least between the electromechanical conversion elements among the legs of the recesses of the adhesive target member having recesses in the portions facing the plurality of electromechanical conversion elements provided on the substrate. It is known that the member to be bonded is adhered to the substrate by adhering the positioned leg portion to the substrate with an adhesive.

For example, Patent Document 1 describes a piezoelectric element in which a piezoelectric element is formed on a vibrating plate forming a part of a side surface of the pressurized liquid chamber in order to pressurize the pressurized liquid chamber of the liquid discharge head of an inkjet recording device. A liquid discharge head using a substrate is disclosed. In this liquid discharge head, the leg portion of the recess of the reinforcing substrate (adhesion target member) having the recess in the portion facing each piezoelectric element (electromechanical conversion element) on the piezoelectric element substrate is placed on the piezoelectric element substrate. It is glued with an adhesive.

Generally, in an electromechanical conversion member in which a member to be bonded such as a reinforcing substrate is bonded onto a substrate provided with a plurality of electromechanical conversion elements, the leg portion of the recess facing the electromechanical conversion element and the substrate are used. It is important that the spaces are evenly bonded with an appropriate amount of adhesive. Therefore, it is required to confirm the adhesive state between the leg portion of the member to be adhered and the substrate (whether or not the adhesive is squeezed out, whether or not there is an adhesive deficiency, etc.). However, among the legs of the recesses of the member to be bonded, the bonding points between the legs located between the electromechanical conversion elements and the substrate cannot be visually recognized from the outside by the member to be bonded. There was a problem that the accuracy of checking the state was poor.

In order to solve the above-mentioned problems, the present invention presents at least the electromechanical conversion element among the legs of the recess of the adhesive target member having the recess in the portion facing the plurality of electromechanical conversion elements provided on the substrate. In an electromechanical conversion member in which a member to be bonded is adhered onto the substrate by adhering a leg portion located between them to the substrate with an adhesive, the leg portion of the recess is attached to the member to be bonded. Separately, the substrate has an adhesive state-confirming leg portion to be adhered by an adhesive, and the adhesive state-confirming leg portion has both ends in the arrangement direction of the plurality of electromechanical conversion elements in the adhesive target member. characterized in that it is a partition wall which partitions the interior of the provided that the through-hole outward.

According to the present invention, the accuracy of confirming the bonding state of the bonding portion between the leg portion of the recess of the bonding target member located between the electromechanical conversion elements and the substrate is improved, and the bonding target member is appropriately bonded to the substrate. The excellent effect of being able to realize a highly reliable electromechanical conversion member is achieved.

It is a partially broken perspective view which shows the internal structure of the liquid discharge head in an embodiment. It is a top view of the actuator board which constitutes the liquid discharge head. It is sectional drawing of the liquid discharge head in AA'in FIG. It is sectional drawing of the liquid discharge head in CC'in FIG. It is sectional drawing which shows the modification of the piezoelectric element which made the lower electrode an individual electrode layer and made the upper electrode a common electrode layer. (A) to (d) are cross-sectional views showing a cross section orthogonal to the arrangement direction of the nozzle holes in order to explain the pre-stage portion of the manufacturing process of the liquid discharge head. (A) to (c) are cross-sectional views showing a cross section orthogonal to the arrangement direction of the nozzle holes in order to explain the middle part of the manufacturing process of the liquid discharge head. (A) to (c) are cross-sectional views showing a cross section orthogonal to the arrangement direction of the nozzle holes in order to explain the latter part of the manufacturing process of the liquid discharge head. It is a top view of the holding board adhered to the actuator board. It is sectional drawing which shows the part (the array part of a piezoelectric element) which cut the liquid discharge head so that it passes through a piezoelectric element along the nozzle hole arrangement direction (piezoelectric element arrangement direction). It is sectional drawing which shows the other part (the part including the leg part for confirming an adhesive state) which cut the liquid discharge head so that it passes through a piezoelectric element along a nozzle hole arrangement direction (piezoelectric element arrangement direction). It is a top view of the holding substrate of the modification which provided the leg part for confirming an adhesive state in the peripheral area of the holding substrate. In the modified example, it is a cross-sectional view which cut the liquid discharge head so as to pass through the adhesive state confirmation leg along the nozzle hole arrangement direction (piezoelectric element arrangement direction). It is a top view which shows the state which the actuator substrate is formed on silicon wear. FIG. 2 is a cross-sectional view showing a part of the liquid discharge head cut so as to pass through the adhesive state confirmation legs arranged on the outer sides of both ends in the piezoelectric element arrangement direction in the second embodiment. FIG. 2 is a cross-sectional view showing a part of the liquid discharge head cut so as to pass through the adhesive state confirmation legs arranged at the four corners of the holding substrate in the second embodiment. It is sectional drawing which shows the state which removed the main body part except the leg part 200a, 200b of a holding board 200. It is a plane explanatory view of the main part which shows an example of the apparatus which discharges a liquid. It is a side side explanatory drawing of the main part which shows an example of a liquid discharge unit. It is a plane explanatory view of the main part which shows the other example of a liquid discharge unit. It is a front explanatory view which shows still another example of a liquid discharge unit.

Hereinafter, an embodiment in which the electromechanical conversion member according to the present invention is applied to a liquid discharge head of an inkjet recording device as an image forming device which is a device for discharging liquid will be described.

First, the configuration of the liquid discharge head will be described.
FIG. 1 is a partially cutaway perspective view showing the internal configuration of the liquid discharge head of the present embodiment.
FIG. 2 is a top view of an actuator board constituting the liquid discharge head.
FIG. 3 is a cross-sectional view of the liquid discharge head in AA'in FIG.
FIG. 4 is a cross-sectional view of the liquid discharge head in CC'in FIG.
In FIG. 2, for the sake of explanation, the holding substrate 200, which is a member to be adhered to be adhered to the actuator substrate, is in a state of being removed.

The liquid discharge head of the present embodiment is mainly composed of an actuator substrate 100, a holding substrate 200, and a nozzle substrate 300. The actuator substrate 100 includes a piezoelectric element 101 as an electromechanical conversion element that generates liquid discharge energy on an element mounting surface (upper surface in the drawing) of the diaphragm 102 as a displacement plate. In the piezoelectric element 101 of the present embodiment, as shown in FIG. 3, the piezoelectric layer 101-3 is sandwiched between the common electrode layer 101-1 which is a lower electrode and the individual electrode layer 101-2 which is an upper electrode. It has a structure like that. However, as shown in FIG. 5, a piezoelectric element may be used in which the lower electrode is the individual electrode layer 101-2 and the upper electrode is the common electrode layer 101-1.

Further, the actuator substrate 100 is provided with a partition wall portion 103 on a surface (lower surface in the drawing) opposite to the element mounting surface of the diaphragm 102. The space surrounded by the diaphragm 102, the partition wall portion 103, and the nozzle substrate 300 is the pressurized liquid chamber 104. Further, the actuator substrate 100 also forms the fluid resistance portion 105 and the common liquid chamber 106.

The holding substrate 200 includes an ink supply port for supplying ink from an ink cartridge, and by being adhered to the actuator substrate 100, the common ink flow path 202 and the diaphragm 102 of the actuator substrate 100 can be flexed and displaced. It forms a recess 203 that forms a space. The holding substrate 200 can be formed by silicon etching, a plastic molded product, or the like.

In the nozzle substrate 300, the nozzle holes 301 are formed at positions corresponding to the individual pressurized liquid chambers 104. As the nozzle substrate 300, for example, one formed by subjecting a plate made of SUS to punching, etching, silicon etching, nickel electroforming, resin laser processing, or the like can be used.

In the liquid discharge head of the present embodiment, each pressurized liquid chamber 104 is filled with ink, and a drive voltage signal is transmitted from the drive IC 120 to each individual electrode layer 101-2 under the control of a control unit (not shown). Apply. As this drive voltage signal, a pulse voltage of 20 [V] generated by the oscillation circuit can be used. By applying such a voltage pulse, the piezoelectric layer 101-3 itself contracts in the direction parallel to the diaphragm 102 due to the piezoelectric effect. As a result, the vibrating plate 102 bends so as to be convex toward the pressurized liquid chamber 104, and as a result, the pressure in the pressurized liquid chamber 104 rises sharply, and ink is ink from the nozzle hole 301 communicating with the pressurized liquid chamber 104. Is ejected.

After the pulse voltage is applied, the shrunken piezoelectric layer 101-3 returns to its original position, and the vibrating diaphragm 102 also returns to its original position. Therefore, the pressure inside the pressurized liquid chamber 104 becomes negative as compared with the inside of the common liquid chamber 106, and the ink supplied from the ink cartridge through the ink supply port has fluid resistance from the common ink flow path 202 and the common liquid chamber 106. It is supplied to the pressurized liquid chamber 104 via the section 105. By repeating this, droplets of ink can be continuously ejected, and an image is formed on a recording material arranged facing the liquid ejection head.

Next, a method of manufacturing the liquid discharge head according to the present embodiment will be described.
6 to 8 are cross-sectional views showing a cross section orthogonal to the arrangement direction of the nozzle holes in order to explain the manufacturing process of the liquid discharge head of the present embodiment.

As the substrate of the actuator substrate 100, it is preferable to use a silicon single crystal substrate, and it is usually preferable to have a thickness of 100 to 600 μm. There are three types of plane orientations, (100), (110), and (111), but (100) and (111) are generally widely used in the semiconductor industry, and in this embodiment, mainly ((111) is used. A single crystal substrate having a plane orientation of 100) is used. Further, at the stage of producing the pressurized liquid chamber 104, the silicon single crystal substrate is processed by using etching, and in this case, anisotropic etching is generally used as the etching method. Anisotropic etching utilizes the property that the etching rate differs with respect to the plane orientation of the crystal structure. For example, in anisotropic etching in which the surface is immersed in an alkaline solution such as KOH, the etching rate of the (111) surface is about 1/400 as compared to that of the (100) surface. Therefore, in the plane orientation (100), a structure having an inclination of about 54 ° can be produced, whereas in the plane orientation (110), a deep groove can be formed, and the arrangement density is increased while maintaining more rigidity. be able to. Therefore, it is also possible to use a single crystal substrate having the plane orientation of (110). However, in this case, SiO ₂ which is a mask material is also etched, so it is necessary to pay attention to this point.

First, as shown in FIG. 6A, a film to be a diaphragm 102 is formed on the silicon single crystal substrate. Since the diaphragm 102 is repeatedly deformed by receiving the force generated by the piezoelectric element 101, it is preferable that the diaphragm 102 has sufficient strength to withstand this force. Examples of the material include those produced by the CVD method of _{Si, SiO 2} , and Si ₃ N _4. Further, for the diaphragm 102, it is preferable to select a material having a coefficient of linear expansion close to that of the individual electrode layer 101-2 or the piezoelectric layer 101-3 bonded to the diaphragm 102. In particular, in the present embodiment, since PZT is used as the piezoelectric layer 101-3, the coefficient of ^{linear expansion close to the coefficient of linear expansion of 8 × 10 -6} [1 / K] is 5 × 10 ^-6. A material having a linear expansion coefficient of [1 / K] to 10 × 10 ^-6 [1 / K] is preferable, and further, 7 × 10 ^-6 [1 / K] to 9 × 10 ^-6 [1 / K]. A material having a coefficient of linear expansion of is more preferable. Specific materials include aluminum oxide, zirconium oxide, iridium oxide, ruthenium oxide, tantalum oxide, hafnium oxide, osmium oxide, rhenium oxide, rhodium oxide, palladium oxide and their compounds, and these are sputtered or used. It can be produced by a spin coater using the Sol-gel method. The film thickness is preferably 0.1 to 10 μm, more preferably 0.5 to 3 μm. If it is smaller than this range, it becomes difficult to process the pressurized liquid chamber 104, and if it is larger than this range, the diaphragm 102 is less likely to be deformed and displaced, and the ejection of ink droplets tends to be unstable.

Next, the common electrode layer 101-1 is formed on the diaphragm 102 thus formed. The common electrode layer 101-1 is preferably a single metal film layer or a plurality of layers composed of a metal film and an oxide film, and in either case, an adhesive layer is inserted between the diaphragm 102 and the metal film. It is preferable to suppress peeling and the like.

The adhesion layer, after the sputtering of Ti, with a RTA (rapid thermal annealing) apparatus, 650 to 800 ° C., 1 to 30 minutes, and thermally oxidizing the titanium film in an _{O 2} atmosphere, the titanium oxide film and a titanium film To. Reactive sputter may be used to form the titanium oxide film, but a thermal oxidation method using a high temperature of the titanium film is preferable. Fabrication by reactive sputtering requires a special sputtering chamber configuration because the silicon substrate needs to be heated at a high temperature. Further, the crystallinity of the titanium oxide film is better in the oxidation by the RTA device than in the oxidation by a general furnace. This is because, according to the oxidation by a normal heating furnace, the titanium film, which is easily oxidized, forms a number of crystal structures at a low temperature, and it is necessary to break them once. Therefore, oxidation by RTA, which has a high rate of temperature rise, is advantageous for forming good crystals. Further, as the material other than Ti, materials such as Ta, Ir, and Ru are also preferable. The film thickness is preferably 10 nm to 50 nm, more preferably 15 nm to 30 nm. In the case of less than this range, there is a concern about the adhesion, and if it exceeds this range, the quality of the crystal of the electrode film formed on it will be affected.

Further, as the metal film for forming the common electrode layer 101-1, platinum having high heat resistance and low reactivity has been conventionally used, but it is said that it has sufficient barrier property against lead. In some cases, platinum group elements such as iridium and platinum-rhodium, or alloy films thereof may be used. Further, when platinum is used _{, the adhesion to the substrate (particularly SiO 2} ) is poor, so it is preferable to laminate the above-mentioned adhesion layer first. As a manufacturing method, vacuum film formation such as a sputtering method or vacuum vapor deposition is generally used. The film thickness is preferably 80 to 200 nm, more preferably 100 to 150 nm. If it is thinner than this range, it will not be possible to supply a sufficient current as a common electrode, and problems will occur when ejecting ink. In addition, if it is thicker than this range, the cost will increase when an expensive material of platinum group element is used, and when platinum is used as a material, the surface roughness will be increased when the film thickness is increased. The problem is that the oxide electrode film or PZT produced on the oxide electrode film or PZT has a large surface roughness and crystal orientation, so that sufficient displacement cannot be obtained for ink ejection.

The metal oxide film for creating the common electrode layer 1011, as a material, it is preferable to use SrRuO _3. Other than _{this, Sr x A (1-x} ) Ru y materials as described in _{B (1-y)} may also be mentioned (A = Ba, Ca, B = Co, Ni, x, y = 0~0 .5). A sputtering method can be adopted as the film forming method. _{The film quality of the SrRuO 3} thin film changes depending on the sputtering conditions, but since the crystal orientation is particularly important and the SrRuO ₃ film is also oriented at (111) following the Pt (111) used for the metal film, the film formation temperature is It is preferable to heat the substrate at 500 ° C. or higher to form a film.

Regarding the crystallinity of the _{SrRuO 3} thin film formed on Pt (111), since the lattice constants of _{Pt and SrRuO 3 are close, the 2θ positions of SrRuO 3} (111) and Pt (111) in normal 2θ / θ measurement. Are overlapped, making it difficult to distinguish. For Pt, due to the extinction rule, the diffraction lines cancel each other out at the position where 2θ tilted by 35 ° in the Psi direction is about 32 °, and the diffraction intensity is not seen. Therefore, by tilting the Psi direction by about 35 ° and determining that 2θ has a peak intensity in the vicinity of about 32 °, _{it is possible to confirm whether SrRuO 3} is preferentially oriented to (111). When Psi was shaken at 2θ = 32 ° _{, almost no diffraction intensity was observed in SrRuO 3} (110) at Psi = 0 °, and diffraction intensity was observed near Psi = 35 °. _{It was confirmed that SrRuO 3} was oriented at (111) in the one prepared under the film forming conditions of the embodiment. Further, in the SrRuO _{3 film thus produced, the diffraction intensity of SrRuO 3} (110) can be seen when Psi = 0 °.

When it was estimated how much the displacement amount after constant driving deteriorated compared to the initial displacement amount when the piezoelectric element 101 was continuously displaced, the orientation of PZT had a great influence. Insufficient in suppressing displacement deterioration. Furthermore, _{when looking at the surface roughness of the SrRuO 3} film, the film formation temperature has an effect, and the surface roughness is very small at room temperature to 300 ° C. and becomes 2 nm or less. In this case, _{the surface roughness of the SrRuO 3} film is very flat, but the crystallinity is not sufficient, and the initial displacement amount and the displacement amount deterioration after continuous driving of the piezoelectric element 101 formed after that are not sufficient. Sufficient characteristics cannot be obtained. The surface roughness is preferably 4 nm to 15 nm, more preferably 6 nm to 10 nm. If it exceeds this range, the withstand voltage of the PZT formed thereafter is very poor, and leakage is likely to occur. Therefore, in order to obtain good crystallinity and surface roughness, it is preferable to carry out the film formation in the range of 500 ° C. to 700 ° C., preferably 520 ° C. to 600 ° C. The surface roughness is an index of the surface roughness (average roughness) measured by an atomic force microscope (AFM).

Regarding the composition ratio of Sr and Ru after the formation of the SrRuO ₃ film, it is preferable that Sr / Ru is 0.82 or more and 1.22 or less. If it deviates from this range, the specific resistance becomes large, and sufficient conductivity cannot be obtained as the common electrode layer 101-1. The _{film thickness of the SrRuO 3} film is preferably 40 nm to 150 nm, more preferably 50 nm to 80 nm. If it is thinner than this film thickness range, sufficient characteristics cannot be obtained for the initial displacement amount and the displacement amount deterioration after continuous driving, and it is difficult to obtain the function as a stop etching layer for suppressing PZT overetching. There is a problem with this point. On the other hand, if it is thicker than this film thickness range, the dielectric strength of the PZT formed thereafter is very poor, and leakage is likely to occur. Further, the specific resistance of _{the SrRuO 3} ^{film is preferably 5 × 10 -3} Ω · cm or less, and more preferably 1 × 10 ^-3 Ω · cm or less. If it becomes larger than this range, the contact resistance of the common electrode layer 101-1 at the interface with the electrode in contact with the common electrode layer 101-1 becomes large, and sufficient current cannot be supplied as the common electrode layer 101-1. There is a problem when doing this.

Next, as shown in FIG. 6B, the piezoelectric layer 101-3 is formed on the common electrode layer 101-1. In this embodiment, PZT is used as the material of the piezoelectric layer 101-3. PZT is a solid solution of lead zirconate (PbZrO ₃ ) and titanium acid (PbTIO ₃ ), and its characteristics differ depending on the ratio. Generally, a composition exhibiting excellent piezoelectric properties is _{shown as Pb (Zr 0.53} , Ti _0.47 ) O _{3 in a ratio of PbZrO 3} to PbTiO _{3 in} a ratio of 53:47, which is represented by a chemical formula. Examples of the composite oxide other than PZT include barium titanate. In this case, it is also possible to prepare a barium titanate precursor solution by using barium alkoxide or a titanium alkoxide compound as a starting material and dissolving it in a common solvent. Is. These materials are described by the general formula ABO ₃ , and correspond to composite oxides containing A = Pb, Ba, Sr, B = Ti, Zr, Sn, Ni, Zn, Mg, and Nb as main components, and specific examples thereof. The description is, for example, (Pb _1-x , Ba) (Zr, Ti) O ₃ and (Pb _1-x , Sr) (Zr, Ti) O ₃ . These mean the case where Pb of the A site is partially replaced with Ba or Sr. Such substitution is possible if it is a divalent element, and its effect is to reduce the deterioration of characteristics due to evaporation of lead during heat treatment.

As a method for producing the piezoelectric layer 101-3, a sputtering method or a Sol-gel method can be used to produce the piezoelectric layer 101-3 with a spin coater. In that case, patterning is required, so a desired pattern can be obtained by photolithography etching or the like. When PZT is prepared by the Sol-gel method, a PZT precursor solution can be prepared by using lead acetate, zirconium alkoxide, and a titanium alkoxide compound as starting materials and dissolving them in methoxyethanol as a common solvent to obtain a uniform solution. Since the metal alkoxide compound is easily hydrolyzed by the moisture in the atmosphere, an appropriate amount of a stabilizer such as acetylacetone, acetic acid, or diethanolamine may be added to the precursor solution as a stabilizer.

When a PZT film is obtained on the entire surface of the underlying substrate, it is obtained by forming a coating film by a solution coating method such as spin coating and performing heat treatments of solvent drying, thermal decomposition, and crystallization. Since the transformation from the coating film to the crystallized film is accompanied by volume shrinkage, it is necessary to adjust the precursor concentration so that a film thickness of 100 nm or less can be obtained in one step in order to obtain a crack-free film. The layer thickness of the piezoelectric layer 101-3 is preferably 0.5 to 5 μm, more preferably 1 μm to 2 μm. If it is smaller than this range, sufficient displacement cannot be generated, and if it is larger than this range, many layers are laminated, so that the number of steps increases and the process time becomes long.

The relative permittivity of the piezoelectric layer 101-3 is preferably 600 or more and 2000 or less, and more preferably 1200 or more and 1600 or less. If it is smaller than this range, it is difficult to obtain sufficient displacement characteristics, and if it is larger than this range, the polarization treatment is not sufficiently performed and it is difficult to obtain sufficient characteristics due to displacement deterioration after continuous driving.

After forming the piezoelectric layer 101-3, the individual electrode layer 101-2 is next formed. Like the common electrode layer 101-1, the individual electrode layer 101-2 is preferably a single metal film layer or a plurality of layers composed of a metal film and an oxide film. As the oxide film, the oxide film described in the common electrode layer 101-1 can be used. At this time, _{the film thickness of the SrRuO 3} film is preferably 20 nm to 80 nm, and more preferably 40 nm to 60 nm. Further, as the metal film, the metal film described in the common electrode layer 101-1 can be used. At this time, the film thickness is preferably 30 to 200 nm, more preferably 50 to 120 nm.

Next, as shown in FIG. 6C, an interlayer insulating film 110 is formed in order to insulate between the common electrode layer 101-1 and the piezoelectric element 101 and the lead-out wiring 108 to be formed later. Further, the interlayer insulating film 110 needs to be a dense inorganic material because it is necessary to prevent damage to the piezoelectric element 101 due to the steps of film formation and etching and to select a material in which moisture in the atmosphere does not easily permeate. be. Organic materials are not suitable because the film thickness needs to be increased in order to obtain sufficient protection performance. This is because if the interlayer insulating film 110 is a thick film, the deformation of the diaphragm 102 is hindered, resulting in an inkjet head having low ejection performance.

Oxides, nitrides, and carbides are preferably used for the interlayer insulating film 110 in order to obtain high protection performance in a thin film, but the electrode material, piezoelectric material, and diaphragm material that are the base of the interlayer insulating film 110 are used. It is necessary to select a material with high adhesion. Further, as for the film forming method, it is necessary to select a film forming method that does not damage the piezoelectric element 101. That is, the plasma CVD method in which the reactive gas is converted into plasma and deposited on the substrate, or the sputtering method in which the plasma is collided with the target material and blown to form a film is not preferable. Examples of the preferred film forming method include a vapor deposition method and an ALD method, but the ALD method, which has a wide choice of materials that can be used, is preferable. Preferred materials include, for example, oxide films used for ceramic materials such _{as Al 2} O ₃ , ZrO ₂ , Y ₂ O ₃ , Ta ₂ O ₃ , and TIO _2. In particular, by using the ALD method, a thin film having a very high film density can be produced and damage during the process can be suppressed.

The film thickness of the interlayer insulating film 110 needs to be a thin film sufficient to secure the protective performance of the piezoelectric element 101, and at the same time, it needs to be as thin as possible so as not to hinder the deformation of the diaphragm 102. Therefore, the preferable range of the film thickness of the interlayer insulating film 110 is 20 nm to 100 nm. If it is thicker than 100 nm, the amount of deformation of the diaphragm 102 is reduced, so that the inkjet head has low ejection efficiency. On the other hand, if it is thinner than 20 nm, the function of the piezoelectric element 101 as a protective layer is insufficient, and the performance of the piezoelectric element 101 deteriorates.

Further, the interlayer insulating film 110 may have a two-layer structure. In this case, as shown in FIG. 4, the second layer of the insulating protective film 110b is thickened, and the second layer of the insulating protective film is provided in the vicinity of overlapping with the piezoelectric element 101 so as not to hinder the deformation of the diaphragm 102. It may be configured to remove only the first layer of the insulating protective film 110a. At this time, as the insulating protective film 110b of the second layer, any oxide, nitride, carbide or a composite compound thereof can be used, but SiO ₂ generally used in semiconductor devices can be used. .. Any method can be used for film formation, and a CVD method and a sputtering method can be exemplified. Considering the step coating, it is preferable to use a CVD method capable of forming an isotropic film. The film thickness of the interlayer insulating film 110 needs to be such that the insulation is not broken down by the voltage applied between the common electrode layer 101-1 and the individual electrode layer 101-2. That is, it is necessary to set the electric field strength applied to the insulating protective film within a range that does not cause dielectric breakdown. Further, considering the surface property of the substrate of the interlayer insulating film 110, pinholes, and the like, the film thickness of the interlayer insulating film 110 is preferably 200 nm or more, and more preferably 500 nm or more.

After forming the interlayer insulating film 110, a connection hole 111 for connecting the individual electrode layer 101-2 and the lead-out wiring 108 is formed by a litho-etch method. Further, when the common electrode layer 101-1 is connected to another lead-out wiring, a connection hole is similarly formed in the interlayer insulating film 110. After that, as shown in FIG. 6D, the lead-out wiring 108 is formed.

The material of the lead-out wiring 108 is preferably a metal electrode material made of any one of Ag alloy, Cu, Al, Au, Pt, and Ir. As a manufacturing method, it is manufactured by a sputtering method or a spin coating method, and then a desired pattern is obtained by photolithography etching or the like. The film thickness of the lead-out wiring 108 is preferably 0.1 to 20 μm, more preferably 0.2 to 10 μm. If it is smaller than this range, the resistance becomes large and a sufficient current cannot flow through the individual electrode layer 101-2, and the head discharge becomes unstable. Also, if it is larger than this range, the process time will be long. The contact resistance of the connection hole 111 with the individual electrode layer 101-2 is preferably 1 Ω or less, more preferably 0.5 Ω or less. The contact resistance of the connection hole with the common electrode layer 101-1 is preferably 10 Ω or less, more preferably 5 Ω or less. If it exceeds these ranges, it will not be possible to supply a sufficient current, and problems will occur when ejecting ink.

Further, the lead-out wiring 108 is also interposed in the adhesive region of the holding substrate 200, as will be described later. Therefore, in the present embodiment, in order to ensure height uniformity in the adhesive region of the holding substrate 200, as shown in FIG. 4, the side opposite to the lead-out wiring 108 (common ink flow path 202) with the piezoelectric element 101 interposed therebetween. Even in the adhesive region 109 to which the holding substrate 200 is adhered on the side), the same layer structure as the adhesive region on the lead-out wiring 108 side is left, and the adhesive reliability of the holding substrate 200 is enhanced.

Next, as shown in FIG. 7A, a passivation film 112 that functions as a protective layer for the lead-out wiring 108 is formed. By providing such a passivation film 112, an inexpensive Al or an alloy material containing Al as a main component can be used as the material of the lead-out wiring 108. As a result, it is possible to obtain a low-cost and highly reliable inkjet head. As the material of the passivation membrane 112, any inorganic material or organic material can be used, but it is necessary to use a material having low moisture permeability. Examples of the inorganic material include oxides, nitrides and carbides, and examples of the organic material include polyimide, acrylic resin and urethane resin. However, in the case of an organic material, a thick film is required, so that it is not suitable for patterning described later. Therefore, it is preferable to use an inorganic material because it can exhibit a wiring protection function with a thin film. In particular, it is a technique that has a proven track record in semiconductor devices and is preferable to use the passivation film 112 of _{Si 3} N _{4 for} the lead-out wiring 108 of Al. The film thickness of the passivation film 112 is preferably 200 nm or more, more preferably 500 nm or more. If the film thickness is thin, the passivation function cannot be sufficiently exerted, so that the lead wiring 108 is broken due to corrosion, which lowers the reliability of the inkjet.

Further, it is preferable that the passivation film 112 removes the piezoelectric element 101 and the portion overlapping around the piezoelectric element 101 so as not to hinder the deformation of the diaphragm 102. This makes it possible to obtain an inkjet head with high efficiency and high reliability. Specifically, as shown in FIG. 7B, the end of the lead-out wiring 108 to be the individual electrode pad 107 connected to the drive IC 120 and the piezoelectric element 101 by using a photolithography method or a dry etching method. The passivation film 112 and the interlayer insulating film 110 at the portion of the upper surface and the common ink flow path 202 are removed. Then, as shown in FIG. 7 (c), the diaphragm 102 at the position where the common ink flow path 202 and the common liquid chamber 106 communicate with each other is removed by the litho etching method.

At the end of the lead-out wiring 108, an individual electrode pad 107 made of a bump electrode for connecting the drive IC 120 is formed. Examples of the method for forming the individual electrode pad 107 include an electrolytic plating method, an electroless plating method, and a stud bump method. Materials of the individual electrode pad 107 include Au, Ag, Cu, Ni, solder and the like. As a method of connecting the drive IC 120 to the individual electrode pad 107, for example, ACF (Anisotropic Conductive Film) bonding using FPC (Flexible Printed Circuits), solder bonding, wire bonding bonding, and flip-chip directly bonding to the output terminal of the drive IC 120 are performed. Chip bonding and the like can be selectively used. However, if FPC is used, the cost of FPC parts is high, so wire bonding or flip-chip bonding is more cost-effective. Further, wire bonding bonding has a slower tact than flip chip bonding, so that productivity is poor and it is disadvantageous for narrowing the pitch. Therefore, in the present embodiment, the drive IC 120 is connected to the individual electrode pad 107 by flip-chip bonding, and the drive IC 120 is mounted on the flip chip.

Next, as shown in FIG. 8A, the leg portion 200a of the holding substrate 200 having the recess 203 formed at the position corresponding to the diaphragm displacement region 113 and the adhesive region 109 on the actuator substrate 100 are bonded to each other. Adhere at 114. If the actuator substrate 100 has a thickness of about 20 to 100 μm for forming the pressurizing liquid chamber 104 or the like, sufficient rigidity cannot be secured. Therefore, the holding substrate 200 is adhered to secure the rigidity. Therefore, it is preferable that the holding substrate 200 is not a low-rigidity material such as resin but a high-rigidity material such as silicon. Further, in order to prevent the actuator substrate 100 from warping, it is necessary to select a material having a coefficient of thermal expansion close to that of the actuator substrate 100. Therefore, it is preferable to use a ceramic material such as glass, silicon, SiO ₂ , ZrO ₂ , Al ₂ O _{3 or the like.}

Further, a recess 203 is formed at a position corresponding to the diaphragm displacement region 113 facing the piezoelectric element 101 of the holding substrate 200. The recess 203 secures a space for the piezoelectric element 101 to be deformed. As shown in FIGS. 9 and 10, each recess 203 of the holding substrate 200 is partitioned by one piezoelectric element 101. As a result, sufficient rigidity can be ensured even with the actuator substrate 100 having a thin plate thickness, and mutual interference between adjacent pressurizing liquid chambers 104 when driving each piezoelectric element 101 can be reduced. .. Further, as shown in FIGS. 9 and 10, since the recess 203 of the holding substrate 200 is partitioned for each piezoelectric element 101, high processing accuracy is required for increasing the density of the piezoelectric element 101. For example, in the case of realizing a liquid discharge head capable of recording an image of 300 dpi, the width T1 of the partition wall that partitions the recess 203 of the holding substrate 200 is preferably 5 to 20 μm.

Next, as shown in FIG. 8B, the pressurized liquid chamber 104, the common liquid chamber 106, and the partition wall portion 103 other than the fluid resistance portion 105 are covered with a resist by the litho method, and then an alkaline solution (KOH solution or KOH solution or Aniometric wet etching is performed with TMHA solution) to form a pressurized liquid chamber 104, a common liquid chamber 106, and a fluid resistance portion 105. In addition to the heterogeneous etching with an alkaline solution, the pressurized liquid chamber 104, the common liquid chamber 106, and the fluid resistance portion 105 may be formed by, for example, dry etching using an ICP etcher. After that, as shown in FIG. 8C, the nozzle substrate 300 having the nozzle hole 301 opened is joined to the position corresponding to each pressurized liquid chamber 104.

The above description is an example of a method for manufacturing a liquid discharge head, and is not limited to this.

Next, the configuration of the adhesive region for adhering the holding substrate 200 to the actuator substrate 100 will be described.
The connection portion between the drive IC 120 and the individual electrode pad 107 formed at the end of the lead-out wiring 108 is likely to be disconnected from the drive IC 120 and the individual electrode pad 107 when an external force such as bending or impact is applied. In addition, the connection between the drive IC 120 and the individual electrode pad 107 may be disconnected due to thermal stress. Further, due to changes in temperature and humidity, moisture may adhere to the connection portion between the drive IC 120 and the individual electrode pad 107, and the connection portion may be corroded. Therefore, it is necessary to seal and reinforce the connection portion between the drive IC 120 and the individual electrode pad 107 with a sealant.

In the present embodiment, as shown in FIG. 9, the holding substrate 200 is formed with an IC accommodating portion 201 for accommodating the drive IC 120. As shown in FIG. 4, the sealant 130 is placed in the IC accommodating portion 201 of the holding substrate 200, and the connection portion between the drive IC 120 and the individual electrode pad 107 is covered with the sealant 130 and sealed. ..

In the present embodiment, it is important that the legs 200a of the recess 203 provided in the holding substrate 200 are evenly adhered to the adhesive region 109 on the actuator substrate 100 with an appropriate amount of the adhesive 114. Therefore, with respect to the adhesive 114 that adheres between the leg portion 200a of the holding substrate 200 and the adhesive region 109 of the actuator substrate 100, is there an excessive protrusion of the adhesive 114, or is there a shortage of the adhesive 114? It is required to confirm whether or not (adhesive state). The suitability of this bonded state can be determined, for example, by looking at the fillet shape of the adhesive 114 interposed at the bonded portion. However, among the leg portions 200a of the holding substrate 200, the holding substrate 200 exists at the bonding portion between the leg portion 200a located between the piezoelectric elements 101 and the adhesive region 109 on the actuator substrate 100 as shown in FIG. Therefore, it cannot be visually recognized from the outside.

As for the bonded state at the bonded portion that cannot be visually recognized, for example, a method of observing the bonded portion through the holding substrate 200 using an infrared microscope (IR microscope) can be mentioned. However, this method has a problem that the image observed by the IR microscope is unclear and the adhesive state (fillet shape of the adhesive 114, etc.) cannot be properly confirmed, and the confirmation accuracy is poor. Further, when a material that inhibits infrared rays is used for the holding substrate 200 or the like, there may be a problem that it is not possible to even confirm the bonded state of the bonded portion.

Further, for example, of the leg portion 200a of the holding substrate 200, the adhesive portion between the leg portion 200a visible from the outside and the adhesive region 109 on the actuator substrate 100 (for example, as shown in FIG. 4, through the common ink flow path 202). By confirming the adhesive state (the shape of the fillet of the adhesive 114, etc.) of the visible adhesive portion), the invisible adhesive portion (the adhesive portion between the leg portion 200a located between the piezoelectric elements 101 and the adhesive region 109) can be found. One method is to infer the adhesive state. However, since the structure is different between such a visible adhesive portion and an invisible adhesive portion, the premise of the adhesive state is different, such as a difference in the amount of adhesive 114 adhered to both adhesive portions. Therefore, there is a problem that the estimation accuracy in inferring the adhesive state of the invisible adhesive portion from the adhesive state of the visible adhesive portion is poor, and the accuracy of confirming the adhesive state of the invisible adhesive portion is poor.

Therefore, in the present embodiment, as shown in FIGS. 9 and 11, the adhesive state confirmation leg portion 200b is provided on the holding substrate 200, and the adhesive state confirmation leg portion 200b is placed on the actuator substrate 100 by the adhesive 114. It is glued. Since the leg portion 200b for confirming the adhesive state is provided separately from the leg portion 200a of the recess 203 provided in the holding substrate 200, its structure and the like function as the leg portion 200a of the recess 203 of the holding substrate 200. There are no restrictions. Therefore, the bonding portion between the leg portion 200b for confirming the bonding state and the actuator board 100 may be bonded under the same or the same conditions as the bonding location between the leg portion 200a located between the piezoelectric elements 101 and the actuator board 100, or externally. It is possible to configure it so that it is easy to see from.

In the present embodiment, as shown in FIGS. 9 and 11, a plurality of through holes 204 are formed in the holding substrate 200, and the partition wall portion partitioning the through holes 204 is a leg portion 200b for confirming the adhesive state. As a result, the bonding portion between the bonding state confirmation leg portion 200b and the actuator substrate 100 can be visually recognized from the outside through the through hole 204. Further, in the present embodiment, the surface layer on the actuator substrate 100 to which the adhesive state confirmation leg 200b is adhered is the adhesive region 109 on the actuator substrate 100 to which the leg 200a located between the piezoelectric elements 101 is adhered. It is the same layer as the surface layer. As a result, the adhesive portion between the adhesive state confirmation leg portion 200b and the actuator substrate 100 is formed by the adhesive 114 under the same or equivalent conditions as the adhesive portion between the leg portion 200a located between the piezoelectric elements 101 and the actuator substrate 100. Be glued.

As a result, according to the present embodiment, the piezoelectric element 101 is visually recognized from the through hole 204 the adhesive state (fillet shape of the adhesive 114, etc.) of the adhesive portion between the adhesive state confirmation leg portion 200b and the actuator substrate 100. It is possible to infer with high accuracy the bonding state of the bonding portion between the leg portion 200a located between the legs and the actuator substrate 100. Therefore, it is possible to improve the confirmation accuracy of the invisible adhesive portion (the adhesive portion between the leg portion 200a located between the piezoelectric elements 101 and the actuator substrate 100), and the holding substrate 200 is appropriately adhered to the actuator substrate 100. It is possible to realize a liquid discharge head with high performance.

In particular, in the present embodiment, as shown in FIG. 9, leg portions 200b for confirming the adhesive state are provided on the outer sides of both ends of the piezoelectric element 101 in the arrangement direction. As a result, even when the bonding state changes along the arrangement direction of the piezoelectric elements 101 (for example, when the amount of adhesive is biased along the arrangement direction of the piezoelectric elements 101), the bonding state is spread over the arrangement direction of the piezoelectric elements 101. It is possible to infer with high accuracy the bonding state of the bonding portion between the leg portion 200a located between the piezoelectric elements 101 and the actuator substrate 100.

In this embodiment, the adhesive state confirmation leg 200b is provided on both ends of the piezoelectric element 101 in the arrangement direction, but the position where the adhesive state confirmation leg 200b is provided is not limited to this. .. For example, as shown in FIGS. 12 and 13, the adhesive state confirmation leg may be provided in the peripheral region of the holding substrate 200 (four corners of the holding substrate 200 in the illustrated example). Also in this case, it is possible to infer with high accuracy the bonding state of the bonding portion between the leg portion 200a located between the piezoelectric elements 101 and the actuator substrate 100 over the arrangement direction of the piezoelectric elements 101. Further, even when the bonded state changes in the direction orthogonal to the arrangement direction of the piezoelectric elements 101, the bonded state of the bonded portion between the leg portion 200a located between the piezoelectric elements 101 and the actuator substrate 100 is estimated with high accuracy. It becomes possible to do.

Further, in the present embodiment, as shown in FIG. 9, the width T2 of the leg portion 200b for confirming the adhesive state is substantially the same as the width T1 of the leg portion 200a located between the piezoelectric elements 101, so that the adhesive state is formed. The condition of the adhesion portion between the confirmation leg portion 200b and the actuator substrate 100 is close to the condition of the adhesion portion between the leg portion 200a located between the piezoelectric elements 101 and the actuator substrate 100. Therefore, from the adhesive state of the adhesive portion between the leg portion 200b for confirming the adhesive state and the actuator substrate 100, the adhesive state of the adhesive portion between the leg portion 200a located between the piezoelectric elements 101 and the actuator substrate 100 is estimated with higher accuracy. be able to.

[Example 1]
Hereinafter, an embodiment of an electromechanical conversion member composed of the actuator substrate 100 and the holding substrate 200 of the above-described embodiment (hereinafter, this embodiment will be referred to as “Example 1”) will be described.
Regarding the actuator substrate 100, a thermal oxide film (thickness 1 μm) to be a diaphragm 102 is formed on a 6-inch silicon wafer, and then a common electrode layer 101-1 is formed (FIG. 6A). In the formation of the common electrode layer 101-1, first, a titanium film (thickness: 30 nm) was formed as an adhesion layer by a sputtering device, then thermally oxidized at 750 ° C. using RTA, and then platinum as a metal film. A film (thickness 100 nm) and an SrRuO ₃ film (thickness 60 nm) were sputtered and formed as an oxide film. The substrate heating temperature at the time of sputter film formation was 550 ° C.

Next, as the piezoelectric layer 101-3, a solution adjusted to Pb: Zr: Ti = 114: 53: 47 (PZT precursor solution) was prepared, and a piezoelectric film was formed to form a film by a spin coating method. bottom. As a specific PZT precursor solution, lead acetate trihydrate, isopropoxide titanium, and normal propoxide zirconium were used as starting materials. The water of crystallization of lead acetate was dissolved in methoxyethanol and then dehydrated. The amount of lead is excessive with respect to the stoichiometric composition. This is to prevent a decrease in crystallinity due to so-called lead loss during heat treatment. A PZT precursor solution was synthesized by dissolving isopropoxide titanium and normal poxide zirconium in methoxyethanol, proceeding with an alcohol exchange reaction and an esterification reaction, and mixing with the methoxyethanol solution in which lead acetate was dissolved. The PZT concentration of this PZT precursor solution was 0.5 mol / L. Using this PZT precursor solution, a film was formed by spin coating, dried at 120 ° C., and then thermally decomposed at 500 ° C. After the thermal decomposition treatment of the third layer, crystallization heat treatment (temperature 750 ° C.) was performed by RTA (rapid heat treatment). The film thickness at this time was 240 nm. This step was carried out a total of 8 times (24 layers), and finally, a piezoelectric layer 101-3 having a thickness of about 2 μm was obtained.

Next, the individual electrode layer 101-2 is formed. In the formation of the individual electrode layer 101-2, first, an SrRuO ₃ film (thickness 40 nm) was formed as an oxide film, and a Pt film (thickness 125 nm) was sputtered as a metal film. After that, a photoresist (TSMR8800) manufactured by Tokyo Ohka Co., Ltd. was formed by a spin coating method, a resist pattern was formed by a normal photolithography method, and then a Pt film and an oxide film were formed using an ICP etching apparatus (manufactured by Samco Co., Ltd.). After etching, a resist stripping device manufactured by Semitool Co., Ltd. was used to perform resist stripping treatment for 30 minutes using an amine-based stripping solution, and an asher manufactured by Canon Co., Ltd. was used to perform ashing treatment for 3 minutes. The patterning of No. 2 was performed (FIG. 6 (b)).

Similarly, after forming a resist pattern by a photolithography method, the piezoelectric layer 101-3 was etched, resist peeling treatment and ashing treatment were performed, and the piezoelectric layer 101-3 was patterned (FIG. 6 (b)). ..

In the first embodiment, a row of piezoelectric elements consisting of 300 piezoelectric elements 101 is regarded as one chip in a two-row set, and as shown in FIG. 14, 64 chips are manufactured from one silicon wafer.

Next, after forming the pattern of the common electrode layer 101-1 by the photolithography method (FIG. 6B), resist peeling treatment and ashing treatment are performed to pattern the common electrode layer 101-1, and then the two layers are formed. An interlayer insulating film 110 made of the same material is formed (FIG. 6 (c)). In forming the interlayer insulating film 110, first, an Al ₂ O ₃ film was formed at 50 nm _{using the ALD method, and then a SiO 2} film was formed at 1 μm using the CVD method. After the interlayer insulating film 110 was formed, a connection hole 111 for connecting the individual electrode layer 101-2 and the lead wiring 108 was formed by etching (FIG. 6 (c)).

Next, Al was sputter-deposited as the adhesive regions 109 and 109'(convex portions) to which the lead-out wiring 108, the wiring for the common electrode, and the legs 200a and 200b of the holding substrate 200 were adhered, and patterned by etching ( FIG. 6 (d)).

Next, the passivation film 112 is formed (FIG. 7 (a)). In the formation of the passivation film 112, Si ₃ N ₄ was formed into a film at 500 nm by a plasma CVD method, and the portion where the individual electrode pad 107 was formed was etched (FIG. 7 (b)). Next, the portion of the diaphragm 102 that becomes the common ink flow path 202 was removed by dry etching (FIG. 7 (c)). After that, an individual electrode pad 107 or the like for connection with a drive IC or the like is formed on the lead-out wiring 108 or the wiring for the common electrode by the stud bump 121 made of Au, and the holding substrate 200 is formed as shown in FIG. The actuator substrate 100 to be bonded was formed.

Next, the production of the holding substrate 200 will be described.
First, the Si wafer was polished to a thickness of 400 μm to form an oxide film on the actuator substrate 100 side of the holding substrate 200. Next, the oxide film at the portion serving as the recess 203, the IC accommodating portion 201, the common ink flow path 202, and the through hole 204 for forming the adhesive state confirmation leg portion 200b was removed by photolithography patterning. Then, a resist was formed on the patterned oxide film, and a resist for forming a through hole penetrating the holding substrate 200 such as the IC accommodating portion 201, the common ink flow path 202, and the through hole 204 was photolithographically patterned. Then, as shown in FIG. 9, through holes such as the IC accommodating portion 201, the common ink flow path 202, and the through holes 204 were formed by ICP etching. At this time, the thickness of the partition wall portion partitioning the through hole 204, that is, the width of the adhesive state confirmation leg portion 200b is set to 10 μm, which is the same as the leg portion 200a of the recess 203 of the holding substrate 200.

Subsequently, only the resist on the actuator substrate 100 side of the holding substrate 200 was removed, and the concave portion 203 was formed by half-etching the actuator substrate 100 side by ICP etching using the first patterned oxide film pattern as a mask. Finally, by removing the oxide film on the entire surface, the holding substrate 200 having the IC accommodating portion 201, the common ink flow path 202, the recess 203, and the through hole 204 was formed. In the first embodiment, a plurality of through holes 204 are provided at both ends of the piezoelectric element 101 in the arrangement direction and at the four corners of the holding substrate 200 so that the bonded state of the legs 200a over the entire holding substrate 200 can be easily grasped. Was formed, and the leg portion 200b for confirming the adhesive state was arranged.

The adhesive surface (the surface of the leg portion 200a) of the holding substrate 200 thus formed is coated with an epoxy adhesive 114 by a flexographic printing machine so that the film pressure of the adhesive is 2.0 μm. The holding substrate 200 was adhered to the actuator substrate 100 by applying the adhesive 114 to the adhesive region on the actuator substrate 100. After that, the drive IC 120 was flip-chip mounted on the individual electrode pads 107 of the actuator substrate 100, and the sealant 130 was injected into the IC housing section 201 from the gap between the IC housing section 201 and the drive IC 120 to cure the drive IC 120.

[Example 2]
Next, another embodiment of the electromechanical conversion member composed of the actuator substrate 100 and the holding substrate 200 of the above-described embodiment (hereinafter, this embodiment is referred to as “Example 2”) will be described.
In the second embodiment, as shown in FIGS. 15 and 16, the leg portion 200a of the recess 203 of the holding substrate 200 covers a region on the actuator substrate 100 to which the adhesive state checking leg portion 200b of the holding substrate 200 is adhered. An electromechanical conversion member similar to that of the first embodiment was formed except that the structure was the same as that of the bonded region 109 on the actuator substrate 100 to be bonded. Specifically, the leg portion 200a of the recess 203 of the holding substrate 200 is composed of a convex portion formed on the interlayer insulating film 110 (the same wiring layer as the lead wiring 108 and the convex portion formed by the passivation film 112). It is bonded onto the bonding area 109. In the second embodiment, the region on the actuator substrate 100 to which the adhesive state confirmation leg portion 200b of the holding substrate 200 is adhered is also configured to be a convex portion 109'with the same layer structure.

Since such a convex portion 109'can be formed by a manufacturing process together with the adhesive region 109 to which the leg portion 200a of the concave portion 203 of the holding substrate 200 is adhered, the number of manufacturing steps does not increase.

[Comparative example]
In addition, an electromechanical conversion member as a comparative example was also formed for the effect confirmation test described later.
In the comparative example, the electromechanical conversion member similar to that of the first embodiment was formed except that the holding substrate 200 was not provided with the adhesive state confirmation leg 200b.

[Effect confirmation test]
First, with respect to the electromechanical conversion member formed in Examples 1 and 2, the bonding portion between the bonding state confirmation leg portion 200b and the actuator substrate 100 is observed with an optical microscope through the through hole 204 of the holding substrate 200, and the bonding portion thereof is observed. The fillet shape of the adhesive 114 at the bonded portion was confirmed. On the other hand, for the electromechanical conversion member formed in the comparative example, the fillet shape of the adhesive 114 at the bonding portion between the leg portion 200a of the recess 203 and the actuator substrate 100 is measured from the common ink flow path 202 of the holding substrate 200 with an optical microscope. Observed by. Next, with respect to the electromechanical conversion members formed in Examples 1 and 2 and Comparative Example, as shown in FIG. 17, the main body portion excluding the legs 200a and 200b of the holding substrate 200 is removed, and between the piezoelectric elements 101. The positioned leg portion 200a was exposed, and the fillet shape of the adhesive 114 at the bonding portion between the leg portion 200a and the actuator substrate 100 was directly observed with an optical microscope.

In the electromechanical conversion members of Examples 1 and 2, the fillet shape of the bonding portion between the bonding state confirmation leg portion 200b and the actuator substrate 100 is the bonding location between the leg portion 200a located between the piezoelectric elements 101 and the actuator substrate 100. It was confirmed that the shape of the adhesive 114 was almost the same as that of the adhesive 114, and that there was a high correlation between the two. On the other hand, in the electromechanical conversion member of the comparative example, the fillet shape of the adhesive 114 at the bonding portion between the leg portion 200a of the recess 203 facing the common ink flow path 202 and the actuator substrate 100 is a leg located between the piezoelectric elements 101. It was confirmed that the shape was different from the fillet shape of the adhesive 114 at the bonding portion between the portion 200a and the actuator substrate 100, and the correlation between the two was low.

Next, an example of the device for discharging the liquid according to the present invention will be described with reference to FIGS. 18 and 19. FIG. 18 is an explanatory plan view of a main part of the device, and FIG. 19 is an explanatory view of a side surface of the main part of the device.

This device is a serial type device, and the carriage 403 is reciprocated in the main scanning direction by the main scanning moving mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, and the like. The guide member 401 is bridged over the left and right side plates 491A and 491B to movably hold the carriage 403. Then, the carriage 403 is reciprocated in the main scanning direction by the main scanning motor 405 via the timing belt 408 bridged between the drive pulley 406 and the driven pulley 407.

The carriage 403 is equipped with a liquid discharge unit 440 in which the liquid discharge head 404 and the head tank 441 according to the present invention are integrated. The liquid discharge head 404 of the liquid discharge unit 440 discharges, for example, liquids of each color of yellow (Y), cyan (C), magenta (M), and black (K). Further, the liquid discharge head 404 is mounted by arranging a nozzle row composed of a plurality of nozzles in a sub-scanning direction orthogonal to the main scanning direction and facing the discharge direction downward.

The liquid stored in the liquid cartridge 450 is supplied to the head tank 441 by the supply mechanism 494 for supplying the liquid stored outside the liquid discharge head 404 to the liquid discharge head 404.

The supply mechanism 494 includes a cartridge holder 451 which is a filling part for mounting the liquid cartridge 450, a tube 456, a liquid feeding unit 452 including a liquid feeding pump, and the like. The liquid cartridge 450 is detachably attached to the cartridge holder 451. Liquid is delivered from the liquid cartridge 450 to the head tank 441 by the liquid feeding unit 452 via the tube 456.

This device includes a transport mechanism 495 for transporting the paper 410. The transport mechanism 495 includes a transport belt 412, which is a transport means, and a sub-scanning motor 416 for driving the transport belt 412.

The transport belt 412 attracts the paper 410 and transports it at a position facing the liquid discharge head 404. The transport belt 412 is an endless belt, and is hung between the transport roller 413 and the tension roller 414. Adsorption can be performed by electrostatic adsorption, air suction, or the like.

Then, the transport belt 412 orbits in the sub-scanning direction by rotationally driving the transport roller 413 via the timing belt 417 and the timing pulley 418 by the sub-scanning motor 416.

Further, on one side of the carriage 403 in the main scanning direction, a maintenance / recovery mechanism 420 for maintaining / recovering the liquid discharge head 404 is arranged on the side of the transport belt 412.

The maintenance / recovery mechanism 420 includes, for example, a cap member 421 that caps the nozzle surface (the surface on which the nozzle is formed) of the liquid discharge head 404, a wiper member 422 that wipes the nozzle surface, and the like.

The main scanning movement mechanism 493, the supply mechanism 494, the maintenance / recovery mechanism 420, and the transport mechanism 495 are attached to a housing including the side plates 491A and 491B and the back plate 491C.

In this apparatus configured in this way, the paper 410 is fed onto the transport belt 412 and sucked, and the paper 410 is conveyed in the sub-scanning direction by the circumferential movement of the conveyor belt 412.

Therefore, by driving the liquid ejection head 404 in response to the image signal while moving the carriage 403 in the main scanning direction, the liquid is ejected onto the stopped paper 410 to form an image.

As described above, since this device includes the liquid discharge head according to the present invention, it is possible to stably form a high-quality image.

Next, another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 20 is an explanatory plan view of a main part of the unit.

This liquid discharge unit includes a housing portion composed of side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid among the members constituting the device for discharging the liquid. It is composed of a discharge head 404.

It should be noted that a liquid discharge unit may be configured in which at least one of the above-mentioned maintenance / recovery mechanism 420 and the supply mechanism 494 is further attached to, for example, the side plate 491B of the liquid discharge unit.

Next, still another example of the liquid discharge unit according to the present invention will be described with reference to FIG. 21. FIG. 21 is a front explanatory view of the unit.

This liquid discharge unit includes a liquid discharge head 404 to which the flow path component 444 is attached, and a tube 456 connected to the flow path component 444.

The flow path component 444 is arranged inside the cover 442. A head tank 441 may be included instead of the flow path component 444. Further, a connector 443 that electrically connects to the liquid discharge head 404 is provided on the upper part of the flow path component 444.

In the present application, the "device for discharging a liquid" is a device provided with a liquid discharge head or a liquid discharge unit and driving the liquid discharge head to discharge the liquid. The device for discharging a liquid includes not only a device capable of discharging a liquid to a device to which the liquid can adhere, but also a device for discharging the liquid into the air or into the liquid.

The "device for discharging the liquid" can also include means for feeding, transporting, and discharging paper to which the liquid can adhere, as well as a pretreatment device, a posttreatment device, and the like.

For example, as a "device that ejects a liquid", an image forming device that is a device that ejects ink to form an image on paper, and a three-dimensional object (three-dimensional object) are formed in layers in order to form a three-dimensional object. There is a three-dimensional modeling device (three-dimensional modeling device) that discharges the modeling liquid into the powder layer.

Further, the "device for discharging a liquid" is not limited to a device in which a significant image such as characters and figures is visualized by the discharged liquid. For example, those that form patterns that have no meaning in themselves and those that form a three-dimensional image are also included.

The above-mentioned "thing to which a liquid can adhere" means a material to which a liquid can adhere at least temporarily, such as a material to which the liquid adheres and adheres, and a material to which the liquid adheres and permeates. Specific examples include paper, recording paper, recording paper, film, recorded media such as cloth, electronic substrates, electronic components such as piezoelectric elements, powder layers (powder layers), organ models, and media such as inspection cells. Yes, and includes everything to which the liquid adheres, unless otherwise specified.

The material of the "material to which liquid can adhere" is temporary liquid such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and flooring, and textiles for clothing. But it is good if it can be attached.

The "liquid" also includes inks, treatment liquids, DNA samples, resists, pattern materials, binders, modeling liquids, or solutions and dispersions containing amino acids, proteins, and calcium.

Further, the "device for discharging the liquid" includes, but is not limited to, a device in which the liquid discharge head and the device to which the liquid can adhere move relatively. Specific examples include a serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like.

In addition, as a "device for ejecting liquid", a treatment liquid coating device for ejecting a treatment liquid to the paper in order to apply the treatment liquid to the surface of the paper for the purpose of modifying the surface of the paper, raw materials. There is an injection granulation device that granulates fine particles of raw materials by injecting a composition liquid dispersed in a solution through a nozzle.

The "liquid discharge unit" is a liquid discharge head integrated with functional parts and a mechanism, and is a collection of parts related to liquid discharge. For example, the "liquid discharge unit" includes a head tank, a carriage, a supply mechanism, a maintenance / recovery mechanism, a main scanning movement mechanism in which at least one of the configurations is combined with a liquid discharge head, and the like.

Here, the term "integration" means, for example, a liquid discharge head and a functional component, a mechanism in which the mechanism is fixed to each other by fastening, bonding, engagement, etc., or one in which one is movably held with respect to the other. include. Further, the liquid discharge head, the functional component, and the mechanism may be configured to be detachable from each other.

For example, as a liquid discharge unit, there is a liquid discharge head and a head tank integrated, such as the liquid discharge unit 440 shown in FIG. In some cases, the liquid discharge head and the head tank are integrated by being connected to each other by a tube or the like. Here, a unit including a filter can be added between the head tank of these liquid discharge units and the liquid discharge head.

Further, as a liquid discharge unit, there is a unit in which a liquid discharge head and a carriage are integrated.

Further, there is a liquid discharge unit in which the liquid discharge head and the scanning movement mechanism are integrated by holding the liquid discharge head movably by a guide member constituting a part of the scanning movement mechanism. Further, as shown in FIG. 20, there is a liquid discharge unit in which a liquid discharge head, a carriage, and a main scanning movement mechanism are integrated.

Further, as a liquid discharge unit, there is a carriage to which a liquid discharge head is attached, in which a cap member which is a part of the maintenance / recovery mechanism is fixed, and the liquid discharge head, the carriage, and the maintenance / recovery mechanism are integrated. ..

Further, as a liquid discharge unit, as shown in FIG. 21, a tube is connected to a head tank or a liquid discharge head to which a flow path component is attached, and the liquid discharge head and a supply mechanism are integrated. ..

The main scanning movement mechanism shall include a single guide member. Further, the supply mechanism includes a single tube and a single loading unit.

Further, the pressure generating means used for the "liquid discharge head" is not limited. For example, in addition to the piezoelectric actuator (which may use a laminated piezoelectric element) as described in the above embodiment, it is composed of a thermal actuator using an electric heat conversion element such as a heat generating resistor, a vibrating plate, and a counter electrode. An electrostatic actuator or the like may be used.

Further, in the terms of the present application, image formation, recording, printing, printing, printing, modeling, etc. are all synonymous.

The above description is an example, and the present invention exerts a peculiar effect in each of the following aspects.
(Aspect A)
Of the legs 200a of the recesses of the member to be bonded such as the holding substrate 200 having the recess 203 in the portion facing the electromechanical conversion element such as a plurality of piezoelectric elements 101 provided on the substrate such as the actuator substrate 100. In the electromechanical conversion member to which the adhesive target member is adhered to the substrate by adhering the leg portions 200a located at least between the electromechanical conversion elements to the substrate with an adhesive 114, the adhesive target member is attached to the adhesive target member. Is characterized in that, apart from the leg portion 200a of the recess 203, a leg portion 200b for confirming an adhesive state to be adhered by the adhesive 114 is provided on the substrate.
As a method of confirming the bonding state at the bonding point between the leg portion located between the electromechanical conversion elements and the substrate, for example, a method of observing the bonding point through the bonding target member using an infrared microscope (IR microscope). There is. However, this method has a problem that the image observed by the IR microscope is unclear and the adhesive state cannot be properly confirmed, and the confirmation accuracy is poor. Further, when a material that inhibits infrared rays is used for the member to be bonded or the like, there may be a problem that the bonding state itself cannot be confirmed.
Further, for example, by confirming the bonding state of the bonding portion between the leg and the substrate which can be visually recognized from the outside among the legs of the recess of the member to be bonded, the leg and the substrate located between the electromechanical conversion elements can be bonded to each other. There is also a method of inferring the bonded state of the bonded portion. However, the structure may be different between the adhesive portion between the leg portion and the substrate that can be visually recognized from the outside and the adhesive portion between the leg portion and the substrate located between the electromechanical conversion elements. In such a case, the premise of the bonding state is different, such as the amount of adhesive adhering at the bonding points of the two is different. The problem of poor (estimation accuracy) arises.
According to this aspect, a leg for confirming the adhesive state is provided on the member to be adhered, and the leg for confirming the adhesive state is adhered to the substrate with an adhesive. Since the leg for confirming the bonding state is provided separately from the leg of the recess of the member to be bonded, its structure and the like are not limited to the function as the leg of the recess of the member to be bonded. Therefore, the bonding points between the legs for checking the bonding state and the substrate are bonded under the same conditions as the bonding points between the legs and the substrate located between the electromechanical conversion elements, or are configured so that they can be easily seen from the outside. It is possible to do it. Therefore, it is possible to confirm the adhesive state of the adhesive portion between the leg for checking the adhesive state and the substrate and infer the adhesive state of the adhesive portion between the leg and the substrate located between the electromechanical conversion elements with high accuracy. It will be possible. As a result, it is possible to improve the accuracy of confirming the bonding state of the bonding portion between the leg portion of the recess of the bonding target member located between the electromechanical conversion elements and the substrate. Therefore, it is possible to realize a highly reliable electromechanical conversion member in which the member to be bonded is appropriately bonded to the substrate.

(Aspect B)
In the aspect A, the bonding state confirmation leg is characterized in that a bonding portion with the substrate is visibly provided from the outside of the bonding target member.
According to this, it is possible to directly observe the adhesive state of the adhesive portion between the adhesive state confirmation leg and the substrate.

(Aspect C)
In the aspect A or B, the partition wall for partitioning the inside of the through hole 204 formed in the adhesive target member is used as the adhesive state confirmation leg.
According to this, the leg portion for confirming the adhesive state can be easily formed. Moreover, it is also possible to directly observe the adhesion state of the adhesion portion between the adhesion state confirmation leg and the substrate through the through hole 204.

(Aspect D)
In any of the embodiments A to C, the width T2 of the bonding state confirmation leg is substantially the same as the width T1 of the recessed leg in the bonding target member.
According to this, it is possible to enhance the correlation between the adhesive state of the adhesive portion between the leg for confirming the adhesive state and the substrate and the adhesive state of the adhesive portion between the leg and the substrate located between the electromechanical conversion elements. .. Therefore, it is possible to improve the accuracy of confirming the bonding state of the bonding portion between the leg portion of the recess of the bonding target member located between the electromechanical conversion elements and the substrate.

(Aspect E)
In any of the embodiments A to D, the adhesive state confirmation leg is provided on the outer sides of both ends in the arrangement direction of the plurality of electromechanical conversion elements.
According to this, even when the adhesive state changes along the arrangement direction of the electromechanical conversion element (for example, when the amount of adhesive is biased along the arrangement direction of the electromechanical conversion element), the electromechanical conversion is performed. It is possible to infer with high accuracy the adhesion state of the adhesion portion between the leg portion located between the electromechanical conversion elements and the substrate over the arrangement direction of the elements.

(Aspect F)
In any of the embodiments A to E, the adhesive state confirmation leg is provided in the peripheral region of the adhesive target member.
According to this, it is easy to observe the adhesive state of the adhesive portion between the leg for confirming the adhesive state and the substrate.

(Aspect G)
In any of the embodiments A to F, the leg portion 200a of the concave portion 203 is adhered to the convex portion 109 provided on the substrate with an adhesive 114, and the adhesive state confirmation leg portion 200b is also formed. It is characterized in that it is adhered with an adhesive 114 on the convex portion 109'provided on the substrate.
According to this, even if the leg portion 200a of the concave portion 203 is adhered to the convex portion 109 provided on the substrate by the adhesive 114, the adhesive portion between the leg portion for confirming the adhesive state and the substrate is adhered. It is possible to enhance the correlation between the adhesive state of the above and the adhesive state of the adhesive portion between the leg portion located between the electromechanical conversion elements and the substrate. Therefore, it is possible to improve the accuracy of confirming the bonding state of the bonding portion between the leg portion of the recess of the bonding target member located between the electromechanical conversion elements and the substrate.

(Aspect H)
The liquid ejection head is characterized in that a liquid such as ink is ejected by deforming the electromechanical conversion element of the electromechanical conversion member according to any one of the embodiments A to G.
It is possible to realize a highly reliable liquid discharge head using a highly reliable electromechanical conversion member in which the member to be bonded is appropriately bonded to the substrate.

(Aspect I)
The liquid discharge unit is characterized by including the liquid discharge head according to the aspect H.
It is possible to realize a highly reliable liquid discharge unit using a highly reliable electromechanical conversion member in which the member to be bonded is appropriately bonded to the substrate.

(Aspect J)
In the aspect I, a head tank for storing the liquid to be supplied to the liquid discharge head, a carriage on which the liquid discharge head is mounted, a supply mechanism for supplying the liquid to the liquid discharge head, and maintenance for maintaining and recovering the liquid discharge head. It is characterized in that the recovery mechanism, at least one of the main scanning moving mechanisms for moving the liquid discharge head in the main scanning direction, and the liquid discharge head are integrated.
It is possible to realize a highly reliable liquid discharge unit using a highly reliable electromechanical conversion member in which the member to be bonded is appropriately bonded to the substrate.

(Aspect K)
A device for ejecting a liquid, such as an inkjet recording apparatus, is characterized by comprising a liquid ejection head according to the aspect H or a liquid ejection unit according to the aspect I or J.
It is possible to realize a placement in which a highly reliable liquid is discharged using a highly reliable electromechanical conversion member in which the member to be bonded is appropriately bonded to the substrate.

100 Piezoelectric board 101 Piezoelectric element 101-1 Common electrode layer 101-2 Individual electrode layer 101-3 Piezoelectric layer 102 Vibrating plate 103 Bulk partition 104 Pressurized liquid chamber 105 Fluid resistance part 106 Common liquid chamber 107 Individual electrode pad 108 Wiring 109 Adhesive area 110 Interlayer insulating film 111 Connection hole 112 Passion film 114 Piezoelectric 130 Sealant 200a Leg 200b Adhesive state confirmation leg 200 Holding substrate 201 IC accommodating portion 202 Common ink flow path 203 Recessed hole 204 Through hole 300 Nozzle substrate 301 Nozzle hole 403 Carriage 404 Liquid discharge head 440 Liquid discharge unit 441 Head tank 450 Liquid cartridge

Japanese Unexamined Patent Publication No. 2014-172281

Claims (10)

Of the legs of the recesses of the adhesive target member having recesses in the portions facing the plurality of electromechanical conversion elements provided on the substrate, at least the legs located between the electromechanical conversion elements are placed on the substrate. In the electromechanical conversion member in which the member to be adhered is adhered on the substrate by adhering with an adhesive.
The member to be adhered has, apart from the leg portion of the recess, a leg portion for confirming an adhesive state to be adhered on the substrate by an adhesive.
The bonding status confirmation legs, electromechanical converting member, characterized in that it is a partition wall for partitioning an interior of said plurality of array opposite ends outwardly provided that the through-hole of the electro-mechanical conversion element in the adherend member .. In the electromechanical conversion member according to claim 1,
The electromechanical conversion member, characterized in that the bonding state confirmation leg is provided in a peripheral region of the bonding target member. Of the legs of the recesses of the adhesive target member having recesses in the portions facing the plurality of electromechanical conversion elements provided on the substrate, at least the legs located between the electromechanical conversion elements are placed on the substrate. In the electromechanical conversion member in which the member to be adhered is adhered on the substrate by adhering with an adhesive.
The member to be adhered has, apart from the leg portion of the recess, a leg portion for confirming an adhesive state to be adhered on the substrate by an adhesive.
The bonding status confirmation legs, electromechanical converting member, characterized in that it is a partition wall which partitions the interior of the provided that the through hole in the peripheral region of the adherend member. In the electromechanical conversion member according to any one of claims 1 to 3.
The bonding state confirmation leg is an electromechanical conversion member characterized in that a bonding portion with the substrate is visibly provided from the outside of the bonding target member . In electromechanical conversion member according to any one of the請Motomeko 1乃Itaru 4,
An electromechanical conversion member characterized in that the width of the leg portion for confirming the bonding state is substantially the same as the width of the leg portion of the recess in the member to be bonded. In electromechanical conversion member according to any one of claims 1乃Itaru 5,
The legs of the concave portion are adhered to the convex portion provided on the substrate with an adhesive.
The electromechanical conversion member, wherein the leg portion for confirming the adhesive state is also adhered to the convex portion provided on the substrate with an adhesive. A liquid discharge head characterized by ejecting a liquid by deforming the electromechanical transducer of the electromechanical conversion element according to any one of claims 1乃optimum 6. A liquid discharge unit comprising the liquid discharge head according to claim 7. In the liquid discharge unit according to claim 8,
A head tank that stores the liquid to be supplied to the liquid discharge head, a carriage on which the liquid discharge head is mounted, a supply mechanism that supplies the liquid to the liquid discharge head, a maintenance / recovery mechanism that maintains and recovers the liquid discharge head, and the liquid. A liquid discharge unit characterized in that at least one of the main scanning movement mechanisms for moving the discharge head in the main scanning direction is integrated with the liquid discharge head. Liquid discharge head according to claim 7, or claim 8 Moshiku an apparatus for discharging a liquid, characterized in that it comprises a liquid discharge unit according to 9.

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