Method for manufacturing liquid discharge head, liquid discharge head, and apparatus for discharging liquid

Abstract

To provide a liquid discharge head in which a piezoelectric element containing a piezoelectric material with a high piezoelectric constant and a drive circuit are formed on the same substrate.SOLUTION: A method for manufacturing a liquid discharge head 1 for discharging liquid in a pressure chamber 4 from a nozzle 2 by controlling, by a drive circuit 101, a drive voltage to be applied to a piezoelectric element 5 provided in a nozzle forming wall 110 of the pressure chamber communicating with the nozzle that discharges the liquid. The method includes: a drive circuit fabrication step of fabricating the drive circuit 101 on a first substrate; a piezoelectric element fabrication step of fabricating the piezoelectric element 5 on a second substrate 100 through a treatment step including a heat treatment at 450°C or higher; and a transfer step of transferring the drive circuit onto the second substrate on which the piezoelectric element has been fabricated. The piezoelectric element and the drive circuit are formed on the second substrate.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a liquid ejection head, a liquid ejection head, and an apparatus for ejecting liquid.

[0002] Conventionally, a liquid ejection head is known in which a drive circuit controls a drive voltage applied to a piezoelectric element provided in a nozzle forming wall of a pressure chamber communicating with a nozzle that ejects liquid, thereby ejecting the liquid in the pressure chamber from the nozzle.

[0003] Patent Document 1 discloses a liquid ejection head in which a drive voltage applied to a piezoelectric actuator (piezoelectric element) provided in a nozzle-forming wall of a fluid chamber (pressure chamber) communicating with a nozzle is controlled by a CMOS drive circuit to eject liquid in the fluid chamber from the nozzle. In order to form a CMOS drive circuit on a substrate on which the piezoelectric actuator is formed, this liquid ejection head employs a piezoelectric actuator including a piezoelectric element (aluminum nitride) made of a piezoelectric material that can be fabricated at temperatures lower than 450°C, a temperature that significantly deteriorates the CMOS drive circuit. Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the past, there was a problem in that it was not possible to form piezoelectric elements containing piezoelectric materials with high piezoelectric constants, such as PZT and KNN, which are manufactured through processing steps including heat treatment at 450°C or higher, and drive circuits on the same substrate. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention provides a method for manufacturing a liquid ejection head in which a drive voltage applied to a piezoelectric element provided in a nozzle forming wall of a pressure chamber communicating with a nozzle that ejects liquid is controlled by a drive circuit to eject the liquid in the pressure chamber from the nozzle, the method comprising: a drive circuit fabrication step of fabricating a drive circuit on a first substrate; a piezoelectric element fabrication step of fabricating piezoelectric elements on a second substrate via a treatment step including a heat treatment at 450°C or higher; and a transfer step of transferring the drive circuit onto the second substrate on which the piezoelectric elements have been fabricated, wherein the piezoelectric elements and the drive circuit are formed on the second substrate. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a liquid ejection head in which a piezoelectric element containing a piezoelectric material with a high piezoelectric constant and a drive circuit are formed on the same substrate. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view schematically showing a nozzle plate vibration type liquid ejection head according to an embodiment. [Figure 2] FIG. 2 is a perspective view schematically showing a nozzle surface of the liquid ejection head. [Figure 3] 2 is an enlarged cross-sectional view of a portion surrounded by a dashed line indicated by the symbol X in FIG. 1. [Figure 4] FIG. 3 is an explanatory diagram showing a wiring portion that connects a drive circuit and a piezoelectric element of the liquid ejection head. [Figure 5] FIG. 3 is an enlarged explanatory view showing a wiring portion connecting a drive circuit and a piezoelectric element of the liquid ejection head. [Figure 6] 5(a) to 5(d) are explanatory views for explaining a drive circuit fabrication step for fabricating a drive circuit on a first substrate in an embodiment. [Figure 7] FIG. 2 is an explanatory diagram for explaining the configuration of the driving circuit. [Figure 8]10(a) to 10(e) are explanatory diagrams for explaining a piezoelectric element fabrication step of fabricating piezoelectric elements on a second substrate, and a transfer step of transferring the drive circuit fabricated in the drive circuit fabrication step onto the second substrate on which the piezoelectric elements have been fabricated, in an embodiment. [Figure 9] 10(a) to 10(e) are explanatory views for explaining a piezoelectric element fabrication step for fabricating a piezoelectric element on a second substrate in a modified example. [Figure 10] 10(a) to 10(d) are explanatory views for explaining a transfer step in which the piezoelectric element fabricated in the piezoelectric element fabrication step is transferred onto a first substrate on which a drive circuit is fabricated in a modified example. [Figure 11] FIG. 1 is a schematic diagram illustrating a printing apparatus according to an embodiment. [Figure 12] FIG. 2 is an explanatory plan view of an example of a head unit of the printing apparatus. [Figure 13] FIG. 10 is an explanatory plan view of the main parts of another printing device. [Figure 14] FIG. 2 is a side view illustrating the main parts of the printing apparatus of the present embodiment. [Figure 15] FIG. 2 is a plan view illustrating a main part of the liquid ejection unit according to the embodiment. [Figure 16] FIG. 2 is a front view illustrating the liquid ejection unit of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment in which the present invention is applied to a liquid ejection head provided in an apparatus for ejecting liquid will be described below. The present invention is not limited to the embodiments shown below, but may be modified, added, modified, deleted, or otherwise altered within the scope of what a person skilled in the art can conceive, and any embodiment is within the scope of the present invention as long as it achieves the functions and effects of the present invention.

[0009] The liquid ejection head in this embodiment is a nozzle plate vibration type liquid ejection head that ejects liquid in a pressure chamber from the nozzle by varying the pressure in the pressure chamber using an actuator provided in a nozzle plate having nozzles. The nozzle plate vibration type has the advantage that droplets can be ejected with less force than a typical unimorph type piezo head (which ejects liquid by vibrating the surface facing a wall portion (nozzle communication wall) having a communication port that communicates with the nozzle of the pressure chamber), and this can reduce the power consumption of the actuator.

[0010] Increasing nozzle density limits the space available for wiring for voltage application, making wiring construction on the substrate surface difficult. By constructing wiring and drive circuits within the substrate, wiring can be laid out even with high nozzle densities (e.g., 1200 npi). Lead zirconate titanate (PZT) is commonly used as the piezoelectric material for actuators due to its high piezoelectric properties. However, when forming a piezoelectric film on a substrate with wiring and drive circuits, the PZT film formation and crystallization temperature must be at least 450°C. Therefore, using PZT as the piezoelectric material would prevent the drive circuits and their wiring within the substrate from withstanding high temperatures. Therefore, in configurations where wiring and drive circuits are constructed within the substrate, a piezoelectric material with a lower film formation temperature than PZT is required, forcing the selection of a material with lower piezoelectric properties than PZT.

[0011] However, in this embodiment, by adopting the manufacturing method described below, even if a high-piezoelectric-constant piezoelectric material such as PZT, potassium sodium niobate (KNN), or a material primarily composed of any of these is used, which is manufactured through a process including a heat treatment at 450°C or higher, it is possible to form a drive circuit and wiring on the same substrate. This allows wiring and drive circuits to be formed on the substrate on which piezoelectric elements made of a high-piezoelectric-constant piezoelectric material are manufactured, enabling high density (e.g., 1200 npi or higher) in a liquid ejection head using a nozzle plate vibration method. Furthermore, the nozzle plate vibration method allows the volume of the pressure chamber to be reduced, thereby enabling further miniaturization of the head.

[0012] FIG. 1 is a cross-sectional view that schematically shows a nozzle plate vibration type liquid ejection head according to this embodiment. FIG. 2 is a perspective view schematically showing the nozzle surface of the liquid ejection head of this embodiment. The liquid ejection head 1 comprises a nozzle plate 110, a pressure chamber substrate 100, and a common liquid chamber substrate 120. In addition, the liquid ejection head 1 also comprises a frame portion 140 and the like, as will be described later.

[0013] The nozzle plate 110 is thin-film shaped and has a plurality of nozzles 2 that eject liquid, and piezoelectric elements 5 that function as electromechanical conversion elements that are annular actuators arranged around the nozzles 2. The pressure chamber substrate 100 has a plurality of pressure chambers (also called individual liquid chambers or pressurized liquid chambers) 4 that communicate with the plurality of nozzles 2. The nozzles 2 (vibration membranes 103) are located on one side of each pressure chamber 4, and openings 4a of the pressure chambers are located on the side opposite this side. The common liquid chamber substrate 120 has a common liquid chamber 3 that communicates with the plurality of pressure chambers 4.

[0014] FIG. 3 is an enlarged cross-sectional view of a portion surrounded by a broken line indicated by the symbol X in FIG. The pressure chamber substrate 100 is an SOI (Silicon on Insulator) substrate, and has a drive circuit 101 and a wiring section 102 on the side where the vibration membrane 103 is formed. The drive circuit 101 is a CMOS circuit including transistors, resistors, etc. The wiring section 102 includes wiring for applying a drive voltage (drive waveform) from the drive circuit 101 to the second electrode 53 (also referred to as an upper electrode).

[0015] The nozzle plate 110 has a nozzle forming section (film) 111 formed with a plurality of nozzles 2 and covering the piezoelectric elements 5, and a liquid-repellent film 112 is formed on the nozzle surface of this nozzle forming section 111. When liquid is continuously ejected, mist generated simultaneously with the ejection adheres to the nozzle surface. If a large amount of this mist adheres to the nozzle surface, the liquid ejected from the nozzles 2 may be affected by the liquid adhering to the nozzle surface and may deviate from the desired landing position. By forming the liquid-repellent film 112 on the nozzle surface, it is possible to prevent the liquid from adhering to the nozzle surface, and it is also possible to prevent the liquid ejected from the nozzles 2 from being affected by the liquid adhering to the nozzle surface.

[0016] The piezoelectric element 5 of the nozzle plate 110 has a first electrode 51 (also referred to as a lower electrode), a piezoelectric film 52, and a second electrode 53 (also referred to as an upper electrode). The piezoelectric element 5 is covered with a first insulating film 8a. The first insulating film 8a has formed therein a hole-shaped fourth contact 7d for electrical connection to the first electrode 51 and a hole-shaped fifth contact 7e for electrical connection to the second electrode 53.

[0017] In addition, the first insulating film 8a is formed with a first lead-out wiring 9a that electrically connects the first electrode 51 of the piezoelectric element 5 and the wiring portion 102 of the pressure chamber substrate 100, and a second lead-out wiring 9b that electrically connects the second electrode 53 of the piezoelectric element 5 and the wiring portion 102 of the pressure chamber substrate 100.

[0018] The first extraction wiring 9a is electrically connected to the first electrode 51 via the fourth contact 7d, and is electrically connected to the wiring portion 102 via the first contact 7a. The second extraction wiring 9b is electrically connected to the second electrode 53 via the fifth contact 7e, and is electrically connected to the wiring portion 102 via the second contact 7b. The first extraction wiring 9a and the second extraction wiring 9b are covered with a second insulating film 8b. In this embodiment, the second insulating film 8b also covers the piezoelectric element 5 and has the function of preventing moisture that has entered the nozzle forming portion 111 made of resin from entering the piezoelectric element 5, thereby protecting the piezoelectric element 5.

[0019] It is also possible to provide lead wiring portions for the first electrode 51 and the second electrode 53, respectively, and to electrically connect them directly to the wiring portion 102 via contacts opened in the vibration membrane. Also, an adhesion improving film for ensuring adhesion with the nozzle forming portion 111 may be formed on the second insulating film 8b.

[0020] The liquid filled in the liquid ejection head 1 flows into the nozzle 2 and forms a meniscus inside the nozzle. When a predetermined drive voltage is applied from the drive circuit 101 to each of the electrodes 51, 53 of the piezoelectric element 5, the piezoelectric film 52 is displaced (vibrated), and the vibrating film 103 vibrates in the vertical direction in FIG. 3 so that the wall of the pressure chamber substrate 100 that separates the pressure chambers 4 acts as a fixed end. The vibration of the vibrating film 103 causes a pressure change in the liquid inside the pressure chamber, and the liquid is ejected from the nozzle 2.

[0021] Furthermore, in the liquid ejection head 1 of this embodiment, a protective film 11 is formed on the inner circumferential surfaces of the nozzles 2, the inner circumferential surfaces of the pressure chambers 4, and the bottom surface of the common liquid chamber 3 as a surface layer that is lyophilic to the liquid ejected by the liquid ejection head 1 and prevents erosion of the liquid. In this embodiment, the liquid ejected by the liquid ejection head 1 is alkaline, and the pressure chamber substrate 100 and vibration membrane 103 that form the pressure chambers 4 are made of single crystal silicon and silicon oxide. These materials are vulnerable to alkaline liquids and are eluted and eroded by alkaline solutions. To prevent this, a liquid-resistant protective film 11 that prevents erosion of the liquid is formed, thereby protecting the pressure chamber substrate 100 and vibration membrane 103 from the liquid.

[0022] Furthermore, the pressure chambers 4 and nozzles 2 are formed by dry etching. Because the dry etching gas contains fluorine, a fluorine-containing surface film is formed on the inner wall surfaces of the pressure chambers 4 and the inner circumferential surface of the nozzle 2 after etching, making the inner wall surfaces of the pressure chambers 4 and the inner circumferential surface of the nozzle 2 liquid-repellent. If the inner circumferential surface of the pressure chamber 4 is liquid-repellent, the liquid will not wet and spread over the inner circumferential surface of the pressure chamber 4 when filling it, which may prevent the pressure chamber 4 from being filled properly with liquid and may result in air bubbles forming in the corners of the pressure chamber 4, etc.

[0023] In this embodiment, the protective film 11 having lyophilic properties is formed on the inner peripheral surface of the pressure chamber 4 and the inner peripheral surface of the nozzle 2, thereby improving the wettability of the liquid to the inner peripheral surfaces of the pressure chamber 4 and the nozzle 2. The protective film 11 only needs to have a higher lyophilicity to the liquid than the film formation surface (the surface below the protective film 11) of the pressure chamber 4 or the nozzle 2 on which the protective film 11 is formed. If the solvent of the liquid is aqueous, a highly hydrophilic protective film is used, and if the solvent of the liquid is oil-based, a highly lyophilic protective film is used, thereby forming a highly lyophilic protective film.

[0024] In this way, by forming the protective film 11, which has lyophilicity to the liquid filling the pressure chamber 4, on the inner circumferential surfaces of the nozzle 2 and the pressure chamber 4, the liquid easily spreads over the inner circumferential surfaces of the pressure chamber 4 and the nozzle 2 when filling the pressure chamber 4. As a result, the liquid filling property can be improved, and the pressure chamber 4 and the nozzle 2 can be filled with the liquid well without applying pressure or suction when filling the liquid. Therefore, it is possible to prevent cracks from occurring in the vibration membrane 103 when filling the liquid.

[0025] Because the solvent for the liquid in this embodiment is aqueous, forming a protective film 11 that does not contain at least fluorine on the inner circumferential surfaces of the pressure chamber 4 and the nozzle 2 improves lyophilicity compared to a fluorine-containing surface film formed by dry etching. Furthermore, because this film comes into direct contact with various liquids, it is desirable to use a liquid-resistant material, such as a metal oxide that forms a passivation state. To further improve lyophilicity, a material in which silicon dioxide (SOI2) is mixed with the passivation metal oxide at the molecular level can be used. The SOI2 of the protective film 11 has hydrophilic OH groups substituted for the O on its surface, thereby imparting further hydrophilicity to the protective film 11. Examples of metals that can be used in the above metal oxides include tantalum (Ta), niobium (Nb), titanium (Ti), zirconium (Zr), hafnium (Hf), and tungsten (W), which have high oxidation state compatibility. Zr and Hf, which have valences similar to those of SOI2, and Ta, which has a valence close to or slightly different from those, are particularly desirable.

[0026] Furthermore, for example, the protective film 11 may have a two-layer structure of a liquid-resistant film and a liquid-philic film. In this case, after a liquid-resistant film is formed on the inner circumferential surfaces of the nozzle 2 and the pressure chamber 4, a liquid-philic film is formed on the liquid-resistant film.

[0027] In this embodiment, a lyophilic protective film 11 is also formed on the surface of the pressure chamber substrate 100 opposite the film-forming surface of the vibration membrane 103, which constitutes the bottom surface of the common liquid chamber 3. However, the protective film 11 on this surface may be liquid-resistant only. However, the process of forming the protective film 11 on the bottom surface of the common liquid chamber 3 must be performed separately from the process of forming the lyophilic protective film on the inner circumferential surface of the nozzle and the wall surfaces of the pressure chamber, which may increase the number of manufacturing steps. Furthermore, by forming the protective film 11 on the bottom surface of the common liquid chamber 3, the liquid can more easily wet and spread across the bottom surface of the common liquid chamber 3, thereby improving the liquid filling performance. For this reason, it is preferable to form a lyophilic protective film 11 on the surface of the pressure chamber substrate 100 opposite the film-forming surface of the vibration membrane 103, which constitutes the bottom surface of the common liquid chamber 3.

[0028] The material of the vibrating membrane 103 may be any material that is at least insulating, such as SOI2, SiN, metal oxide, resin, etc. However, to increase the displacement, a material with a low Young's modulus is desirable, and considering the difference in linear expansion coefficient with the pressure chamber substrate 100, SOI2 (silicon dioxide) is the most desirable material for the vibrating membrane 103, as this difference is relatively small.

[0029] For example, a platinum film can be suitably used for the first electrode layer 151 and the second electrode layer 153. As described above, the piezoelectric material constituting the piezoelectric layer 152 is a piezoelectric material manufactured through a process including heat treatment at 450°C or higher. Specifically, for example, PZT, KNN, or a piezoelectric material containing either of these as a main component is used. Such a piezoelectric material generally has a higher piezoelectric constant than piezoelectric materials (such as AlN and ScAlN) manufactured through a process in which heat treatment is performed at less than 450°C.

[0030] FIG. 4 is an explanatory diagram showing the wiring portion 102 that connects the drive circuit 101 and the piezoelectric element 5 of the liquid ejection head 1 in this embodiment. FIG. 5 is an enlarged explanatory diagram showing the wiring portion 102 that connects the drive circuit 101 and the piezoelectric element 5 of the liquid ejection head 1 in this embodiment. 4, one drive circuit 101 is connected to each of the second electrodes 53 (upper electrodes) of the five piezoelectric elements 5. In more detail, ten nozzle rows extending in the left-right direction in the figure are wired in such a way that five nozzle rows are assigned to each of the top and bottom in the figure.

[0031] In this embodiment, the nozzle pitch in the left-right direction in the figure (nozzle pitch within the same nozzle row) is 212 [μm], and the nozzle pitch in the up-down direction in the figure (nozzle pitch between adjacent nozzle rows) is 191 [μm], and a high nozzle density of 1200 [npi] is achieved by a liquid ejection head consisting of 10 nozzle rows arranged so that the nozzle positions in the left-right direction in the figure are shifted by 21.2 [μm] between adjacent nozzle rows.

[0032] Next, a method for manufacturing the liquid ejection head 1 of this embodiment will be described. Generally, piezoelectric materials that can be fabricated at temperatures below 450°C (such as AlN (aluminum nitride)) have a low piezoelectric constant, which is disadvantageous in terms of the need for high drive voltages, high costs, and low reliability. Therefore, it is desirable to use high-piezoelectric-constant piezoelectric materials such as PZT and KNN, which are fabricated through processing steps that include heat treatment at 450°C or higher. However, when attempting to form a drive circuit on a substrate on which piezoelectric elements containing such high-piezoelectric-constant piezoelectric materials are fabricated, a problem arises in that the drive circuit deteriorates due to heat above 450°C.

[0033] When using piezoelectric elements made of such a high-piezoelectric-constant piezoelectric material, it is conceivable to fabricate a drive circuit on a substrate separate from the one on which the piezoelectric elements are fabricated, and then wire the piezoelectric elements and drive circuit on each substrate using wire bonding or the like. However, such a two-substrate configuration has drawbacks, such as a large wiring area, low manufacturing efficiency, and high cost. Therefore, a new manufacturing method is desired in which piezoelectric elements containing a high-piezoelectric-constant piezoelectric material and drive circuits are formed on the same substrate.

[0034] The manufacturing method of this embodiment first performs a drive circuit fabrication process in which drive circuit 101 is fabricated on a first substrate such as an SOI substrate, and then performs a piezoelectric element fabrication process in which piezoelectric element 5 is fabricated on a second substrate such as a Si substrate through a process including a heat treatment at 450°C or higher. These fabrication processes are performed on separate substrates, the first substrate and the second substrate. Therefore, even if piezoelectric element 5 with a high piezoelectric constant is fabricated on the second substrate through a process including a heat treatment at 450°C or higher, heat degradation of drive circuit 101 fabricated on the first substrate can be avoided.

[0035] Thereafter, in the manufacturing method of this embodiment, a transfer step is carried out in which the drive circuit 101 after being fabricated on the first substrate is transferred onto the second substrate on which the piezoelectric elements 5 are fabricated. As a result, the piezoelectric elements 5 including a piezoelectric material with a high piezoelectric constant such as PZT or KNN fabricated through a processing step including a heat treatment at 450°C or higher and the drive circuit 101 can be formed on the same substrate (pressure chamber substrate 100) that is the second substrate.

[0036] 6(a) to 6(d) are explanatory diagrams for explaining the drive circuit fabrication step for fabricating the drive circuit 101 on the first substrate. The drive circuit 101 is configured by a CMOS circuit and is fabricated on an SOI substrate 200, which serves as a first substrate, as shown in Fig. 6(a). This SOI substrate 200 is a substrate in which a 40-μm-thick p-type active layer 203 made of Si is formed on a 625-μm-thick Si substrate 201 made of a 6-inch wafer, via an oxide film 202 made of a 600-nm-thick BOX layer.

[0037] In this embodiment, a CMOS element consisting of a p-type MOS transistor and an n-type MOS transistor is fabricated on this SOI substrate 200 by a well-known method, as shown in FIG.

[0038] Specifically, a silicon nitride film is first deposited on an SOI substrate 200 and patterned. Then, a field oxide film is formed by steam oxidation at 1050°C, forming element isolation regions 204 for transistors to be fabricated in later processes. Next, a gate oxide film is formed, followed by deposition of a polysilicon film, doping with impurities to provide conductivity, and patterning to form gate electrodes G. Next, ion implantation is performed to dope the n-type with phosphorus and the p-type with boron to form source S and drain D regions, respectively. An interlayer insulating film 205 made of an SOI film is then deposited by LP-CVD and planarized by CMP. Finally, wiring 207 for circuit operation is formed from Al-0.5% Cu, after which a protective film 206 is deposited and planarized.

[0039] After the drive circuit 101 consisting of a CMOS circuit is fabricated on the SOI substrate 200 in this manner as shown in Fig. 6(b), a circuit-side support substrate 210 is then bonded to the side of the SOI substrate 200 on which the drive circuit 101 is fabricated. At this time, in this embodiment, as shown in Fig. 6(c), an intermediate film 220 made of an organic material is formed between the SOI substrate 200 on which the drive circuit 101 is fabricated and the circuit-side support substrate 210. As the intermediate film 220, for example, a polyparaxylylene CVD film is suitable because it can be formed at room temperature and has no film stress.

[0040] Next, a release step is performed as a separation step for separating the drive circuit 101 formed on the SOI substrate 200, which is the first substrate, from the SOI substrate 200. In the release step of this embodiment, the Si substrate 201 of the SOI substrate 200 is polished to make it thinner, and then etched to remove the Si substrate 201 from the SOI substrate 200, as shown in FIG. 6(d). Thereafter, for portions other than the drive circuit 101 (portions corresponding to the piezoelectric elements 5 on the second substrate (MEMS substrate) side, which will be described later), layers (such as the active layer 203 and the interlayer insulating film 205) present on the intermediate film 220 are removed, as shown in FIG. 6(e).

[0041] 8(a) to 8(e) are explanatory diagrams for explaining the piezoelectric element manufacturing process for manufacturing the piezoelectric element 5 on the second substrate, and the transfer process for transferring the drive circuit 101 manufactured in the drive circuit manufacturing process onto the second substrate on which the piezoelectric element 5 is manufactured. In this embodiment, the piezoelectric element 5 is fabricated on a Si substrate 300, which is a silicon wafer, by a well-known method.

[0042] To give a specific example, first, an SOI2 film 301 (vibration film 103) is deposited on a Si substrate 300 by CVD. Then, a Pt film that will become the first electrode 51, which is the lower electrode, is deposited by sputtering. At this time, an adhesive film may be disposed as a base, or a sacrificial layer may be formed for the peel-and-transfer method described below. This sacrificial layer may be the adhesive film described above.

[0043] Next, a piezoelectric film made of PZT is formed by sputtering on the first electrode 51, which is the lower electrode, and a Pt film, which will become the second electrode 53, which is the upper electrode, is formed on top of that. After that, a resist film of a desired shape is formed by photolithography, and the Pt film, which will become the second electrode 53, is patterned by dry etching. Thereafter, the piezoelectric film is patterned in the same manner, and the Pt film, which will become the first electrode 51, is patterned in the same manner. As a result, as shown in FIG. 8(b), a piezoelectric element 5 is formed on the SOI2 film 301 (vibration film 103) of the Si substrate 300.

[0044] Next, as shown in FIG. 8(c), a transfer process is performed to transfer the drive circuit 101 held on the circuit-side support substrate 210 to the Si substrate 300 (hereinafter also referred to as the "MEMS substrate") on which the piezoelectric element 5 is fabricated. In this transfer process, to strengthen the new interface formed by the transfer, the interface (bonding surface) is activated by Ar ion irradiation, followed by the addition of water for hydrophilization. The hydrophilized surfaces are pressed against each other and heated, resulting in interatomic bonding. The heating temperature (heat treatment temperature) is 100°C or higher, preferably 150°C or higher, for a treatment time of approximately 60 minutes. However, to prevent degradation of the drive circuit, it must be below 450°C. A metal acetylacetonate, such as zirconium acetylacetonate, may be added to promote the reaction caused by the SOI2 dissolving and then precipitation, resulting in the disappearance (diffusion) of both interfaces.

[0045] 8(d), the transfer process is completed by removing the circuit-side support substrate 210 and the intermediate film 220. As a result, the drive circuit 101 is integrally formed on the MEMS substrate (Si substrate 300) on which the piezoelectric element 5 is fabricated.

[0046] After the transfer process, wiring section 102 is formed, which opens wiring holes (electrode pads) on the drive circuit 101 side, opens various contacts 7a, 7d, 7e, etc. which are wiring holes for piezoelectric element 5, and forms metal wiring to connect these. In addition, processes necessary for fabricating the head are performed, such as forming a protective film, forming nozzle holes in vibration membrane 103, and forming pressure chambers 4 in Si substrate 300. As a result, as shown in Figure 8(e), a liquid ejection head 1 is formed in which piezoelectric element 5 including PZT and drive circuit 101 are formed on the same substrate.

[0047] [Modification] Next, a modified example of the manufacturing method of the above-described embodiment will be described. In the manufacturing method according to this modification, first, as in the above-described embodiment, a drive circuit fabrication step is carried out in which drive circuit 101 is fabricated on a first substrate such as an SOI substrate, and a piezoelectric element fabrication step is carried out in which piezoelectric element 5 is fabricated on a second substrate such as a Si substrate through a processing step including a heat treatment at 450° C. or higher. In this modification, these fabrication steps are also carried out on separate substrates, the first substrate and the second substrate, so that even if high-piezoelectric-constant piezoelectric element 5 fabricated through a processing step including a heat treatment at 450° C. or higher is fabricated on the second substrate, it is possible to avoid heat degradation of drive circuit 101 fabricated on the first substrate.

[0048] Thereafter, in the manufacturing method of this modified example, a transfer step is carried out in which the piezoelectric elements 5 formed on the second substrate are transferred onto the first substrate on which the drive circuit 101 is formed. As a result, also in this modified example, the piezoelectric elements 5, which are made through a process including a heat treatment at 450°C or higher and include a piezoelectric material with a high piezoelectric constant such as PZT or KNN, and the drive circuit 101 can be formed on the same substrate, the first substrate (pressure chamber substrate 100).

[0049] 9(a) to 9(e) are explanatory diagrams for explaining the piezoelectric element fabrication step of fabricating the piezoelectric element 5 on the second substrate in this modified example. First, a 600-nm-thick oxide film 302 is formed on a Si substrate 300 (second substrate), followed by a 200-nm-thick zinc oxide film 303 formed by sputtering. A 150-nm-thick platinum film, which will become the first electrode 51 (lower electrode), is then formed on top of this by sputtering. The zinc oxide film 303 acts as an adhesive film between the underlying thermal oxide film and the platinum film. The zinc oxide film 303 also effectively improves the crystallinity of the platinum film. The high crystallinity of the platinum film determines the performance of the PZT piezoelectric film, so the zinc oxide film 303 is effective. In addition to zinc oxide, other intermediate films that exhibit this effect include oxides of divalent metal elements such as magnesium oxide, barium oxide, and strontium oxide.

[0050] Next, a 1 μm-thick piezoelectric film made of PZT is formed by sputtering on the platinum film that will become the first electrode 51 (the lower electrode). A 150 nm-thick platinum film that will become the second electrode 53 (the upper electrode) is then formed by sputtering on top of that. A thin film of a conductive oxide material may be inserted at this time to improve the adhesion of the platinum film. A resist film of the desired shape is then formed by photolithography, and the platinum film that will become the second electrode 53 is patterned by dry etching. The piezoelectric film is then patterned in the same manner, and the platinum film that will become the first electrode 51 is also patterned in the same manner. As a result, as shown in FIG. 9(b), a piezoelectric element 5 is formed on the oxide film 302 and zinc oxide film 303 of the Si substrate 300.

[0051] Then, a 50 nm thick aluminum oxide film is deposited by ALD as a protective film 330 for the piezoelectric element 5, followed by a 1.2 μm thick silicon oxide film by CVD, followed by planarization. After the planarization, an intermediate film made of an organic material is placed, and the MEMS-side support substrate 310 is bonded (FIG. 9(c)).

[0052] Next, a release step is carried out as a separation step for separating the piezoelectric elements 5 formed on the Si substrate 300, which is the second substrate, from the Si substrate 300. In the release step of this modification, the Si substrate 300 is polished to make it thinner, and then etched to remove the Si substrate 300 and the oxide film 302, as shown in FIG. 9(d). As a result, in this modification, the zinc oxide film 303, which is disposed as an adhesive layer for the platinum film and serves as a bonding surface with the first substrate (described later), is exposed. Thereafter, the zinc oxide film 303 and the protective film 330 are removed from the portion of the drive circuit 101 on the first substrate (described later), as shown in FIG. 9(e).

[0053] 10(a) to 10(d) are explanatory diagrams for explaining the transfer step of transferring the piezoelectric element 5 produced in the piezoelectric element production step onto the first substrate on which the drive circuit 101 is produced. In this modification, a drive circuit 101 is fabricated on an SOI substrate 200 by a known method, with the formation of an interlayer insulating film 205 completed. In this modification, an active layer 203 of the SOI substrate 200, which is the first substrate on which the drive circuit 101 is fabricated, is used as the vibrating membrane 103.

[0054] In this transfer process, a 100-nm-thick zinc oxide film is deposited by sputtering on the bonding surfaces of both the SOI substrate 200 on which the drive circuit 101 (including the interlayer insulating film 205) has been fabricated and the piezoelectric element 5 fabricated in the piezoelectric element fabrication process, completing the bonding process as shown in Figure 10(b). Bonding can also be achieved by placing a small amount of water on the surface of the zinc oxide film or by exposing it to acetic acid vapor. This utilizes the natural phenomenon whereby crystalline zinc oxide dissolves in water and reprecipitates along the grain boundaries, promoting grain growth, eliminating the bonding interface, and creating a strong bond. A similar phenomenon occurs with metal oxides such as chromium oxide, iron oxide, and magnesium oxide. However, selecting the same material as used to form the platinum bottom electrode is advantageous in terms of process simplification and other production advantages.

[0055] 10(c), the transfer process is completed by removing the MEMS-side support substrate 310. As a result, the piezoelectric element 5 is integrally formed on the first substrate (SOI substrate 200) on which the drive circuit 101 is fabricated.

[0056] After the transfer process, similar to the above-described embodiment, processes required for fabricating the head are performed, such as forming nozzle holes and forming pressure chambers 4 in the Si substrate 201 of the SOI substrate 200. As a result, as shown in Fig. 10(d), a liquid ejection head 1 is formed in which a piezoelectric element 5 including PZT and a drive circuit 101 are formed on the same substrate.

[0057] Next, we will explain PZT-derived ceramics as piezoelectric materials whose main component is PZT. PZT piezoelectric ceramics are materials that have the piezoelectric effect (applying stress generates an electric charge (positive piezoelectric effect), and applying an electric field generates distortion (inverse piezoelectric effect)). Lead zirconate titanate ceramics (PZT) is a well-known material with excellent piezoelectric properties. PZT is a solid solution of lead titanate (PbTiO3) and lead zirconate (PbZrO3), and when lead zirconate is dissolved in lead titanate with a substitution amount x, the chemical formula is Pb(Zr x ,Ti 1-x )O3, and there is a significant improvement in piezoelectricity when x is near 0.5. When the ionic radius of each constituent element is large enough, a solid solution becomes possible if the condition for electrical neutrality is met, and PZT ceramics designed in this way are sometimes called PZT-derived (piezoelectric) ceramics. Specifically, there are PBZT and PLZT in which part of the Pb is replaced with Bi or La, and there are also solid solutions in which tetravalent metal elements (Ti or Zr) are solid-solved with divalent Mg, Ni, Zn and pentavalent Nb or Ta in a ratio that satisfies the condition for electrical neutrality. For example, if the ratio of Mg (divalent) is 1 / 3 and Nb (pentavalent) is 2 / 3, then the result is 2 x 1 / 3 + 5 x 2 / 3 = tetravalent. In this case, the chemical formula is Pb(Mg 1 / 3 ,Nb 2 / 3 )O3 and is commonly abbreviated as PMN. 1 / 3 ,Nb 2 / 3 )O3 is commonly abbreviated as PZN and has the chemical formula: Pb(Ni 1 / 3 ,Nb 2 / 3 )O3 is generally abbreviated as PNN. It also includes ternary piezoelectric ceramics such as PNN-PZ-PT.

[0058] Next, an example of a liquid ejection device according to the present invention will be described with reference to FIGS. FIG. 11 is a schematic explanatory diagram of a printing apparatus that is an inkjet recording apparatus, which is an image forming apparatus serving as a device that ejects liquid in this embodiment. FIG. 12 is an explanatory plan view of an example of a head unit of the printing apparatus of this embodiment.

[0059] A printing apparatus 500, which is an apparatus for ejecting this liquid, includes a carry-in means 501 that carries in a continuum 510, and a guide / conveyance means 503 that guides and conveys the continuum 510 carried in from the carry-in means 501 to a printing means 505. The printing apparatus 500 also includes a printing means 505 that ejects a liquid onto the continuum 510 to form an image, a drying means 507 that dries the continuum 510, and an ejection means 509 that ejects the continuum 510.

[0060] The continuous web 510 is sent out from a main winding roller 511 of the carry-in means 501, guided and conveyed by the rollers of the carry-in means 501, the guide and conveying means 503, the drying means 507, and the conveying means 509, and wound up by a winding roller 591 of the conveying means 509. In the printing means 505, the continuous web 510 is conveyed on a conveying guide member 559 opposite the head unit 550, and an image is printed by liquid ejected from the head unit 550.

[0061] In the printing device 500 of this embodiment, the head unit 550 includes the two head modules 100A and 100B according to this embodiment described above, mounted on a common base member 552.

[0062] When the direction in which the liquid ejection heads 1 of the head modules 100A and 100B are lined up in a direction perpendicular to the transport direction is defined as the head arrangement direction, the head arrays 1A1 and 1A2 of the head module 100A eject liquid of the same color. Similarly, the head arrays 1B1 and 1B2 of the head module 100A are paired, the head arrays 1C1 and 1C2 of the head module 100B are paired, and the head arrays 1D1 and 1D2 are paired, and each ejects liquid of the required color.

[0063] Next, another example of a printing apparatus as a liquid ejecting apparatus according to the present invention will be described with reference to FIGS. FIG. 13 is an explanatory plan view of the main parts of the printing apparatus of this embodiment. FIG. 14 is an explanatory side view of the main part of the printing apparatus of this example.

[0064] The printing apparatus 500 of this example is a serial type apparatus, and a carriage 403 is moved back and forth in the main scanning direction by a main scanning movement mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, etc. The guide member 401 is hung between left and right side plates 491A and 491B to movably hold the carriage 403. The main scanning motor 405 then moves the carriage 403 back and forth in the main scanning direction via a timing belt 408 hung between a drive pulley 406 and a driven pulley 407.

[0065] This carriage 403 is equipped with a liquid ejection unit 440 that integrates the liquid ejection head 1 according to the present invention and a head tank 441. The liquid ejection head 1 ejects liquid of each color, for example, yellow (Y), cyan (C), magenta (M), and black (K). The liquid ejection head 1 is mounted with a nozzle row consisting of multiple nozzles arranged in a sub-scanning direction perpendicular to the main scanning direction, and the ejection direction facing downward. The liquid ejection head 1 is connected to a liquid circulation device, which circulates and supplies liquid of the required color.

[0066] The printing apparatus 500 is equipped with a transport mechanism 495 for transporting 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 ejection head 1. The transport belt 412 is an endless belt that is stretched between a transport roller 413 and a tension roller 414. The attraction can be achieved by electrostatic attraction or air suction. The transport belt 412 moves in a circular motion in the sub-scanning direction as the transport roller 413 is rotationally driven by the sub-scanning motor 416 via a timing belt 417 and a timing pulley 418.

[0067] Furthermore, a maintenance and recovery mechanism 420 that maintains and recovers the liquid ejection head 1 is disposed on one side of the carriage 403 in the main scanning direction, beside the conveyor belt 412. The maintenance and recovery mechanism 420 is composed of, for example, a cap member 421 that caps the nozzle surface of the liquid ejection head 1, a wiper member 422 that wipes the nozzle surface, and the like. The main scanning movement mechanism 493, the maintenance and recovery mechanism 420, and the conveyor mechanism 495 are attached to a housing that includes side plates 491A and 491B and a back plate 491C.

[0068] In the printing device 500 configured in this manner, the paper 410 is fed onto the conveyor belt 412 and adsorbed thereon, and the paper 410 is conveyed in the sub-scanning direction by the circular movement of the conveyor belt 412. Then, by driving the liquid ejection head 1 in accordance with an image signal while moving the carriage 403 in the main scanning direction, liquid is ejected onto the stationary paper 410 to form an image.

[0069] Next, another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 15 is a plan view illustrating the main parts of the liquid discharge unit of this embodiment.

[0070] This liquid ejection unit 440 is composed of the components that make up the device for ejecting the liquid, including a housing portion consisting of side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid ejection head 1.

[0071] It is also possible to configure a liquid discharge unit in which the above-described maintenance and recovery mechanism 420 is further attached to, for example, the side plate 491B of this liquid discharge unit 440.

[0072] Next, still another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 16 is an explanatory front view of the liquid discharge unit of this embodiment.

[0073] This liquid discharge unit 440 is composed of a liquid discharge head 1 to which a flow path part 444 is attached, and a tube 456 connected to the flow path part 444 .

[0074] The flow path part 444 is disposed inside the cover 442. A head tank 441 may be included instead of the flow path part 444. A connector 443 for electrically connecting the flow path part 444 to the liquid ejection head 1 is provided on the upper part of the flow path part 444.

[0075] In the present application, the liquid to be ejected may have a viscosity and surface tension that allows it to be ejected from the head, and is not particularly limited. However, it is preferable that the viscosity of the liquid be 30 mPa·s or less at room temperature and normal pressure, or upon heating or cooling. More specifically, the liquid may be a solution, suspension, emulsion, or the like containing a solvent such as water or an organic solvent, a colorant such as a dye or a pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, or an edible material such as a natural colorant. These liquids can be used, for example, in inkjet inks, surface treatment solutions, liquids for forming components of electronic devices or light-emitting elements, liquids for forming electronic circuit resist patterns, and material liquids for 3D modeling.

[0076] The liquid to be ejected may be a metal material such as solder or a material that is fixed at room temperature, such as wax ink, that is heated and melted before being ejected from the nozzle. Alternatively, the liquid to be ejected may be a liquid that has a high viscosity at room temperature, such as UV ink, that is heated to reduce its viscosity before being ejected from the nozzle. In this case, by providing a heating means such as a heater in the nozzle plate 110, the ejection material in the pressure chamber 4 can be melted or reduced in viscosity, allowing the liquid to be ejected smoothly from the nozzle.

[0077] A "liquid ejection unit" is a liquid ejection head integrated with functional parts and mechanisms, and includes a collection of parts related to ejecting liquid. For example, a "liquid ejection unit" includes a liquid ejection head combined with at least one of the following components: a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, a main scanning movement mechanism, and a liquid circulation device.

[0078] Here, "integrated" includes, for example, a liquid ejection head and a functional part or mechanism that are fixed to each other by fastening, bonding, engaging, etc., or one that is held movably relative to the other. The liquid ejection head, functional part, or mechanism may also be configured to be detachable from each other.

[0079] For example, some liquid ejection units have a liquid ejection head and a head tank integrated together, while others have a liquid ejection head and a head tank integrated together by being connected to each other by a tube, etc. Here, a unit including a filter can be added between the head tank and the liquid ejection head of these liquid ejection units.

[0080] Furthermore, there is a liquid ejection unit in which the liquid ejection head and the carriage are integrated.

[0081] In some liquid ejection units, the liquid ejection head is movably held by a guide member that constitutes part of the scanning movement mechanism, and the liquid ejection head and the scanning movement mechanism are integrated together. In other liquid ejection units, the liquid ejection head, the carriage, and the main scanning movement mechanism are integrated together.

[0082] Furthermore, there is a liquid ejection unit in which a cap member, which is part of the maintenance and recovery mechanism, is fixed to a carriage on which a liquid ejection head is attached, thereby integrating the liquid ejection head, carriage, and maintenance and recovery mechanism.

[0083] In some liquid ejection units, a tube is connected to a liquid ejection head equipped with a head tank or flow path components, integrating the liquid ejection head with a supply mechanism. Liquid is supplied from a liquid storage source to the liquid ejection head via this tube.

[0084] The main scanning movement mechanism includes the guide member alone, and the supply mechanism includes the tube alone and the loading unit alone.

[0085] Here, the "liquid ejection unit" is described in combination with a liquid ejection head, but the "liquid ejection unit" also includes a head module or head unit that includes the liquid ejection head described above, and that integrates the functional components and mechanisms described above.

[0086] "Liquid ejection devices" include devices that are equipped with a liquid ejection head, a liquid ejection unit, a head module, a head unit, etc., and that eject liquid by driving the liquid ejection head. Liquid ejection devices include not only devices that can eject liquid onto objects to which the liquid can adhere, but also devices that eject liquid into air or liquid.

[0087] This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0088] For example, examples of "liquid ejecting devices" include image forming devices that eject ink to form images on paper, and three-dimensional modeling devices (three-dimensional modeling devices) that eject modeling liquid onto a powder layer formed from layers of powder in order to create a three-dimensional object (a three-dimensional model).

[0089] Furthermore, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves, and devices that create three-dimensional images.

[0090] The above-mentioned "object onto which a liquid can adhere" means an object onto which a liquid can adhere at least temporarily, an object onto which the liquid can adhere and stick, an object onto which the liquid can penetrate, etc. Specific examples include media such as paper, recording paper, film, cloth, electronic substrates, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, all objects onto which a liquid can adhere are included.

[0091] The material of the "substance to which a liquid can adhere" may be any material to which a liquid can adhere, even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, or ceramics.

[0092] Furthermore, the "liquid ejection device" may be a device in which a liquid ejection head and an object onto which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which a liquid ejection head moves, and a line type device in which a liquid ejection head does not move.

[0093] Other examples of "liquid ejecting devices" include treatment liquid application devices that eject treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and spray granulation devices that spray a composition liquid in which raw materials are dispersed through a nozzle to granulate the raw material particles.

[0094] In the present application, the terms image formation, recording, printing, copying, printing, modeling, etc. are all synonymous.

[0095] The above description is merely an example, and each of the following aspects provides unique effects. [First aspect] The first aspect is a manufacturing method for a liquid ejection head 1 in which a drive voltage applied to a piezoelectric element 5 provided in a nozzle forming wall (e.g., a nozzle plate 110) of a pressure chamber 4 communicating with a nozzle 2 that ejects liquid is controlled by a drive circuit 101 to eject the liquid in the pressure chamber from the nozzle, and the method includes a drive circuit fabrication step of fabricating the drive circuit 101 on a first substrate (e.g., an SOI substrate 200), a piezoelectric element fabrication step of fabricating a piezoelectric element 5 on a second substrate (e.g., an Si substrate 300) through a processing step including a heat treatment at 450°C or higher, and a transfer step of transferring the drive circuit onto the second substrate on which the piezoelectric element has been fabricated, and is characterized in that the piezoelectric element and the drive circuit are formed on the second substrate. Generally, piezoelectric materials (such as aluminum nitride) that can be fabricated at temperatures below 450°C have low piezoelectric constants, resulting in disadvantages such as high drive voltages, high costs, and low reliability. Therefore, the use of high-piezoelectric-constant piezoelectric materials such as PZT and KNN, which are fabricated through processes including heat treatment at 450°C or higher, is desirable. However, forming a drive circuit on a substrate on which piezoelectric elements containing such high-piezoelectric-constant piezoelectric materials are fabricated presents the problem of deterioration of the drive circuit due to heat above 450°C. Therefore, when using piezoelectric elements made from such high-piezoelectric-constant piezoelectric materials, a possible configuration is to fabricate the drive circuit on a separate substrate from the substrate on which the piezoelectric elements are fabricated, and then wire the piezoelectric elements and the drive circuit on each substrate using wire bonding or other methods. However, such a two-substrate configuration has drawbacks such as a large wiring area, low manufacturing efficiency, and high cost. Therefore, a configuration in which piezoelectric elements containing high-piezoelectric-constant piezoelectric materials and the drive circuit are fabricated on the same substrate is desirable, but this configuration has not been realized until now. In this embodiment, first, a drive circuit is fabricated on a first substrate in a drive circuit fabrication process, and then a piezoelectric element is fabricated on a second substrate through a process including a heat treatment at 450°C or higher in a piezoelectric element fabrication process. These fabrication processes are performed on separate substrates, the first substrate and the second substrate. Therefore, even if a high-piezoelectric-constant piezoelectric element fabricated through a process including a heat treatment at 450°C or higher is fabricated on the second substrate, it is possible to avoid heat degradation of the drive circuit fabricated on the first substrate. In this embodiment, in the transfer step, the drive circuit formed on the first substrate is transferred to the second substrate on which the piezoelectric elements are formed, thereby forming the drive circuit and the piezoelectric elements, which include a piezoelectric material with a high piezoelectric constant such as PZT or KNN and are formed through a process including a heat treatment at 450°C or higher, on the same substrate, the second substrate.

[0096] [Second mode] The second aspect is characterized in that in the first aspect, a separation step (e.g., a peeling step) for separating the driving circuit 101 formed on the first substrate from the first substrate is carried out before the transfer step. According to this method, the unnecessary first substrate is removed before the transfer step of the driving circuit 101 is carried out, so that the driving circuit 101 can be fabricated on the first substrate using an existing manufacturing method.

[0097] [Third aspect] The third aspect is characterized in that in the second aspect, a support substrate bonding process is carried out before the separation process, in which a support substrate (e.g., circuit-side support substrate 210) is bonded to the drive circuit 101 created on the first substrate via an organic intermediate film 220, and in the transfer process, the drive circuit bonded to the support substrate is transferred onto the second substrate. This makes it easier to handle the drive circuit 101 separated from the first substrate in the transfer process.

[0098] [Fourth aspect] The fourth aspect is a manufacturing method for a liquid ejection head 1 in which a drive voltage applied to a piezoelectric element 5 provided in a nozzle forming wall (e.g., a nozzle plate 110) of a pressure chamber 4 communicating with a nozzle 2 that ejects liquid is controlled by a drive circuit 101 to eject the liquid in the pressure chamber from the nozzle, and the method includes a drive circuit fabrication step of fabricating the drive circuit 101 on a first substrate (e.g., an SOI substrate 200), a piezoelectric element fabrication step of fabricating a piezoelectric element 5 on a second substrate (a Si substrate 300) through a processing step including a heat treatment at 450°C or higher, and a transfer step of transferring the piezoelectric element onto the first substrate, and is characterized in that the piezoelectric element and the drive circuit are formed on the first substrate. In this embodiment, as in the first embodiment described above, even if a high-piezoelectric-constant piezoelectric element fabricated through a process including a heat treatment at 450°C or higher is fabricated on a second substrate, it is possible to avoid thermal degradation of the drive circuit fabricated on the first substrate. In this embodiment, the piezoelectric element fabricated on the second substrate is transferred to the first substrate on which the drive circuit is fabricated in the transfer process. This allows the piezoelectric element, which includes a high-piezoelectric-constant piezoelectric material such as PZT or KNN fabricated through a process including a heat treatment at 450°C or higher, and the drive circuit to be formed on the same substrate, the second substrate.

[0099] [Fifth mode] A fifth aspect is characterized in that in the fourth aspect, a separation step of separating the piezoelectric element formed on the second substrate from the second substrate is carried out before the transfer step. According to this method, the unnecessary second substrate is removed before the transfer step of the piezoelectric element 5 is carried out, so that the piezoelectric element 5 can be fabricated on the second substrate using an existing manufacturing method.

[0100] [Sixth aspect] The sixth aspect is the fourth or fifth aspect, characterized in that in the piezoelectric element manufacturing step, the piezoelectric element 5 is manufactured on the second substrate via a zinc oxide intermediate film (zinc oxide film 303), and in the transfer step, the piezoelectric element is transferred onto the first substrate via the zinc oxide intermediate film. This makes it possible to fabricate a piezoelectric element with a higher piezoelectric constant.

[0101] [Seventh aspect] The seventh aspect is characterized in that in any of the first to sixth aspects, the piezoelectric element is made of PZT, KNN, or a material containing either of these as a main component (for example, PZT-derived ceramics). This makes it possible to provide a liquid ejection head using a piezoelectric element containing a piezoelectric material with a high piezoelectric constant.

[0102] [Eighth aspect] The eighth aspect is a liquid ejection head 1 in which a drive voltage applied to a piezoelectric element 5 provided in a nozzle forming wall (e.g., a nozzle plate 110) of a pressure chamber 4 communicating with a nozzle 2 that ejects liquid is controlled by a drive circuit 101 to eject the liquid in the pressure chamber from the nozzle, and the piezoelectric element includes a piezoelectric material made of PZT, KNN, or a material containing either of these as a main component, and the piezoelectric element and the drive circuit are formed on the same substrate. According to this aspect, it is possible to achieve high density nozzles (for example, 1200 npi or more) by using piezoelectric elements containing a piezoelectric material with a high piezoelectric constant.

[0103] [Ninth aspect] A ninth aspect is the eighth aspect, characterized in that the same substrate is a pressure chamber substrate 100 in which the pressure chambers are formed. According to this aspect, it is possible to form the piezoelectric element including the piezoelectric material with a high piezoelectric constant and the drive circuit on the pressure chamber substrate.

[0104] [Tenth aspect] A tenth aspect is a device for ejecting liquid, characterized in that it comprises the liquid ejection head of the eighth or ninth aspect. According to this aspect, it is possible to obtain a device for ejecting liquid with high nozzle density (for example, 1200 npi or more) using piezoelectric elements containing a piezoelectric material with a high piezoelectric constant. [Explanation of symbols]

[0105] 1: Liquid ejection head 2: Nozzle 3: Common liquid chamber 4: Pressure chamber 4a: Opening 5: Piezoelectric element 51:First electrode 52: Piezoelectric film 53:Second electrode 100: Pressure chamber substrate 101: Drive circuit 102:Wiring section 103: Vibration membrane 110: Nozzle plate 111: Nozzle forming section 112: Liquid repellent film 120: Common liquid chamber substrate 140: Frame section 151: First electrode layer 152: Piezoelectric layer 153:Second electrode layer 200: SOI substrate 201: Si substrate 202: Oxide film 203:Active layer 204: Element isolation region 205: Interlayer insulating film 206:Protective film 207: Wiring 210: Circuit side support board 220: Interlayer 300: Si substrate 301 :SOI2 membrane 302: Oxide film 303: Zinc oxide film 310: MEMS side support substrate 330:Protective film 440: Liquid dispensing unit 500:Printing device 550: Head unit [Prior art documents] [Patent documents]

[0106]

Patent Document 1

Claims

1. A method for manufacturing a liquid ejection head in which a drive voltage applied to a piezoelectric element provided in a nozzle forming wall of a pressure chamber communicating with a nozzle that ejects liquid is controlled by a drive circuit to eject liquid in the pressure chamber from the nozzle, the method comprising: a drive circuit fabrication step of fabricating a drive circuit on the first substrate; a piezoelectric element fabrication step of fabricating a piezoelectric element on the second substrate through a treatment step including a heat treatment at 450°C or higher; a transfer step of transferring the drive circuit onto the second substrate on which the piezoelectric element is formed, A method for manufacturing a liquid ejection head, wherein the piezoelectric element and the drive circuit are formed on the second substrate.

2. 2. The method for manufacturing a liquid ejection head according to claim 1, A method for manufacturing a liquid ejection head, comprising the steps of: separating a drive circuit formed on the first substrate from the first substrate;

3. 3. The method for manufacturing a liquid ejection head according to claim 2, a support substrate bonding step of bonding a support substrate to the drive circuit formed on the first substrate via an organic intermediate film is carried out before the separation step; The method for manufacturing a liquid ejection head, wherein the transfer step includes transferring a drive circuit bonded to the support substrate onto the second substrate.

4. A method for manufacturing a liquid ejection head in which a drive voltage applied to a piezoelectric element provided in a nozzle forming wall of a pressure chamber communicating with a nozzle that ejects liquid is controlled by a drive circuit to eject liquid in the pressure chamber from the nozzle, the method comprising: a drive circuit fabrication step of fabricating a drive circuit on the first substrate; a piezoelectric element fabrication step of fabricating a piezoelectric element on the second substrate through a treatment step including a heat treatment at 450°C or higher; a transfer step of transferring the piezoelectric element onto the first substrate, A method for manufacturing a liquid ejection head, comprising forming the piezoelectric element and the drive circuit on the first substrate.

5. 5. The method for manufacturing a liquid ejection head according to claim 4, A method for manufacturing a liquid ejection head, characterized in that a separation step of separating the piezoelectric element formed on the second substrate from the second substrate is carried out before the transfer step.

6. 5. The method for manufacturing a liquid ejection head according to claim 4, In the piezoelectric element fabrication step, a piezoelectric element is fabricated on the second substrate via a zinc oxide intermediate film, The method for manufacturing a liquid ejection head, wherein the transferring step transfers the piezoelectric element onto the first substrate via the zinc oxide intermediate film.

7. 7. The method for manufacturing a liquid ejection head according to claim 1, A method for manufacturing a liquid ejection head, wherein the piezoelectric element is made of PZT, KNN, or a material containing either of these as a main component.

8. A liquid ejection head in which a drive voltage applied to a piezoelectric element provided in a nozzle forming wall of a pressure chamber communicating with a nozzle that ejects liquid is controlled by a drive circuit to eject liquid from the pressure chamber, the piezoelectric element includes a piezoelectric material made of PZT, KNN, or a material containing any of these as a main component; A liquid ejection head, wherein the piezoelectric element and the drive circuit are formed on the same substrate.

9. 9. The liquid ejection head according to claim 8, The liquid ejection head is characterized in that the same substrate is a pressure chamber substrate in which the pressure chambers are formed.

10. A liquid ejection device comprising the liquid ejection head according to claim 8 or 9.

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