Device manufacturing method, head manufacturing method, piezoelectric device, liquid discharge head, liquid discharge apparatus

Abstract

A device manufacturing method for manufacturing a piezoelectric device includes: forming a CMOS element on a first surface of a substrate; forming a piezoelectric element on the first surface of the substrate on which the CMOS element is formed; when the CMOS element or the piezoelectric element is formed, a first insulating film is formed in a region where the piezoelectric element is formed; when forming the piezoelectric element, a lower electrode layer, a piezoelectric layer, an upper electrode layer, and a second insulating film are formed on the first insulating film; after a CMOS element and a piezoelectric element are formed on a substrate, a CMOS wiring layer of the CMOS element and a piezoelectric wiring layer of the piezoelectric element are formed.

Description

Technical Field

[0001] The present embodiment relates to a device manufacturing method, a head manufacturing method, a piezoelectric device, a liquid discharge head, and a liquid discharge apparatus. Background Art

[0002] Piezoelectric devices using vibrating thin films have been tried in various fields. Piezoelectric devices are used in medicine, industry, and the like, and are used in liquid discharge heads, for example.

[0003] As a liquid discharge apparatus using a liquid discharge head, liquid discharge apparatuses using a thermal system (or a bubble system) and a piezoelectric body system are known.

[0004] Thermal systems have small size, high density, and ultra-low cost as their main features (advantages), and are widely used in inkjet printers for offices, home offices (SOHO), and homes. The main reasons for the small size, high density, and ultra-low cost are the simple structure and complementary metal oxide semiconductor (MOS) (CMOS) on a chip (CMOS can be formed on the same substrate as the thermal element for droplet discharge). In contrast, thermal systems have the disadvantages of lower ink freedom and drive durability than piezoelectric systems, and are slightly behind in commercial and industrial printers.

[0005] The piezoelectric system has the main characteristics (advantages) of high driving force (high viscosity and large droplet discharge), high ink freedom, and high driving durability, and is widely used in inkjet printers for commercial and industrial use. Although this is also used in inkjet printers for offices, home offices, and homes, it is significantly inferior to the thermal system in terms of cost competitiveness.

[0006] In a piezoelectric liquid discharge device, a piezoelectric material of lead zirconate titanate (PZT) is generally used, which is generally formed at a high temperature of about 850° C. In an optical device or an ultrasonic device, a CMOS integrated piezoelectric element using PZT or other piezoelectric materials formed at a temperature lower than this temperature has been proposed.

[0007] For example, Patent Document 1 discloses a droplet ejector, which includes: a substrate having a nozzle surface, an electronic component integrated with the substrate, a nozzle forming layer formed on the nozzle surface of the substrate, and a piezoelectric actuator formed on the nozzle forming layer, wherein the electronic component is composed of a CMOS electronic component integrated with the substrate. Patent Document 1 aims to reduce acoustic crosstalk between piezoelectric droplet ejectors and realize a greater number of nozzles.

[0008] Patent document 1 discloses that a piezoelectric body is formed of one or more piezoelectric materials that can be processed at a temperature lower than 450° C. Patent document 1 points out that when the temperature exceeds 300° C. or 450° C., integrated electronic components (e.g., CMOS electronic components) deteriorate, and discloses that the use of a piezoelectric material that can be processed at a temperature lower than 450° C. enables processing of a piezoelectric actuator, as well as integration of electronic components. Summary of the invention

[0009] Technical issues

[0010] Although the piezoelectric system liquid discharge head needs to have excellent piezoelectric characteristics with a large driving force, the CMOS integrated piezoelectric element that can achieve this has not been put into practical use, and there is no example of it being put on the market. From the perspective of management of the manufacturing process, the perspective of ensuring various characteristics of the obtained liquid discharge device, etc., it is difficult to realize a liquid discharge head using a CMOS integrated piezoelectric element. For example, when the formation temperature of the piezoelectric element is lowered as in Patent Document 1, there is a disadvantage that the piezoelectric performance (driving force) of the piezoelectric element is significantly deteriorated or it does not function as a piezoelectric element. On the contrary, when the formation temperature of the piezoelectric element is increased, the disadvantage of CMOS element degradation occurs.

[0011] Furthermore, when the technology of driving the piezoelectric element in the liquid discharge head to vibrate is applied to other uses, it is expected to realize a CMOS integrated piezoelectric element. In this case, it is necessary to be able to perform CMOS operation and obtain excellent piezoelectric characteristics.

[0012] Therefore, an object of this embodiment is to provide a piezoelectric device including a CMOS element and a piezoelectric element on the same substrate, and realizing CMOS operation and excellent piezoelectric characteristics.

[0013] Solutions to the problem

[0014] In a device manufacturing method for manufacturing a piezoelectric device, the device manufacturing method includes: forming a CMOS element on a first surface of a substrate; forming a piezoelectric element on the first surface of the substrate on which the CMOS element is formed; when forming the CMOS element or the piezoelectric element, forming a first insulating film in a region where the piezoelectric element is formed; when forming the piezoelectric element, forming a lower electrode layer, a piezoelectric layer, an upper electrode layer, and a second insulating film on the first insulating film; after forming the CMOS element and the piezoelectric element on the substrate, forming a CMOS wiring layer of the CMOS element and a piezoelectric wiring layer of the piezoelectric element; and after forming the CMOS wiring layer and the piezoelectric wiring layer on the substrate, forming a gap in the substrate from a second surface of the substrate opposite to the first surface.

[0015] A piezoelectric device comprises: a substrate having a gap; a CMOS element on a first surface of the substrate; a first insulating film on the first surface of the substrate; a piezoelectric element on the first insulating film, the piezoelectric element comprising: a lower electrode layer having a first surface on the first insulating film; a piezoelectric layer having a first surface on a second surface of the lower electrode layer opposite to the first surface; and an upper electrode layer having a first surface on a second surface of the piezoelectric layer opposite to the first surface; and a second insulating film formed on the second surface of the upper electrode layer and having a thickness thicker than the first insulating film.

[0016] Effects of the Invention

[0017] According to the present embodiment, it is possible to provide a piezoelectric device that includes a CMOS element and a piezoelectric element on the same substrate and that achieves both CMOS operation and good piezoelectric characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] A more complete understanding of the embodiments of the present disclosure and many of its attendant advantages and features can be readily obtained and understood from the following detailed description with reference to the accompanying drawings.

[0019] [ Figure 1 ]

[0020] Figure 1 is a schematic diagram showing an example of a piezoelectric device according to the present embodiment.

[0021] [ Figure 2 ]

[0022] Figure 2 It is a schematic diagram showing an example of a piezoelectric element.

[0023] [ Figure 3A and 3B ]

[0024] Figure 3A and 3B is a schematic diagram for explaining an example of vibration;

[0025] [ Figure 4A and 4B ]

[0026] Figure 4A and 4B is a schematic diagram for explaining an example of vibration;

[0027] [ Figure 5A and 5B ]

[0028] Figure 5A and 5Bis a schematic diagram for explaining an example of vibration, wherein Figure 5A is an example of a case not included in the present embodiment, Figure 5B is an example of a case included in the present embodiment.

[0029] [ Fig. 6A and 6B ]

[0030] Fig. 6A is a schematic diagram for explaining the nozzle plate vibration system. Figure 6B is a schematic diagram for explaining a conventional exhaust system.

[0031] [ Figure 7 ]

[0032] Figure 7 is a schematic diagram showing an example of a liquid discharge head according to the present embodiment.

[0033] [ Figure 8 ]

[0034] Figure 8 is a schematic diagram showing another example of the liquid discharge head according to the present embodiment.

[0035] [ Fig. 9 ]

[0036] Fig. 9 This is a flowchart illustrating an example of a method for manufacturing a piezoelectric device.

[0037] [ Fig.10 ]

[0038] Fig.10 This is a flowchart illustrating an example of the difference between various characteristics.

[0039] [ Fig.11A and 11B ]

[0040] Fig.11A and 11B It is a schematic diagram for explaining an example of a CMOS element forming process.

[0041] [ Figures 11C to 11E ]

[0042] Figures 11C to 11E It is a schematic diagram for explaining an example of a CMOS element forming process.

[0043] [ Figures 11F to 11H ]

[0044] Figures 11F to 11H It is a schematic diagram for explaining an example of a CMOS element forming process.

[0045] [ Fig. 12A and12B ]

[0046] Fig. 12A and 12B This is a schematic diagram for explaining an example of a piezoelectric element forming process.

[0047] [ Fig. 12C and 12D ]

[0048] Fig. 12C and 12D This is a schematic diagram for explaining an example of a piezoelectric element forming process.

[0049] [ Fig.12E and 12F ]

[0050] Fig.12E is a schematic diagram illustrating an example of a piezoelectric element forming process, Fig.12F It is a schematic diagram for explaining an example of a cavity forming process.

[0051] [ Fig.13 ]

[0052] Fig.13 is a schematic diagram of an example of a liquid discharge device.

[0053] [ Fig.14 ]

[0054] Fig.14 is a schematic diagram of another example of the liquid discharge device.

[0055] [ Fig.15 ]

[0056] Fig.15 is a schematic diagram of an example of a liquid discharge apparatus according to an embodiment of the present disclosure.

[0057] [ Fig.16 ]

[0058] Fig.16 is a schematic diagram of a liquid discharge device according to another embodiment of the present disclosure.

[0059] The accompanying drawings are intended to describe embodiments of the present disclosure and should not be construed as limiting the scope thereof. Unless explicitly noted, the accompanying drawings should not be considered to be drawn to scale. Moreover, throughout the several views, the same or similar reference numerals represent the same or similar components. DETAILED DESCRIPTION

[0060] In describing the embodiments shown in the drawings, specific terms are used for clarity. However, the disclosure of this specification is not intended to be limited to the specific terms selected, and it should be understood that each specific component includes all technical equivalents having similar functions, operating in a similar manner and achieving similar results.

[0061] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0062] Hereinafter, a piezoelectric device, a liquid discharge head, a liquid discharge apparatus, a method for manufacturing a piezoelectric device, and a method for manufacturing a liquid discharge head according to the present embodiment will be described with reference to the accompanying drawings. The present embodiment is not limited to the following embodiments, and other embodiments, additions, changes, deletions, and other changes can be made within the scope that can be thought of by a person skilled in the art. As long as the functions and effects of the present embodiment can be achieved, any method is included in the scope of the present embodiment.

[0063] [Piezoelectric device]

[0064] When a CMOS element and a piezoelectric element are formed on the same substrate (e.g., a Si substrate), the piezoelectric element needs to be formed after the CMOS element is formed from the viewpoint of process management to prevent the semiconductor manufacturing line from being contaminated by heavy metals, alkalis, etc. In this case, in order to ensure (maintain) various characteristics of the previously formed CMOS, the piezoelectric element needs to be formed at a temperature lower than the formation temperature of the CMOS.

[0065] On the contrary, when the formation temperature of the piezoelectric element is lowered, the piezoelectric performance (driving force) of the piezoelectric element is significantly deteriorated, or the piezoelectric element does not function as a piezoelectric element. Therefore, it is difficult to realize a piezoelectric device using a CMOS-integrated piezoelectric element. That is, it has been difficult to realize a piezoelectric device in which a CMOS-integrated piezoelectric element is configured, in which the operation of the CMOS element is ensured, and the excellent piezoelectric characteristics of the piezoelectric element are ensured.

[0066] When a piezoelectric device is used as a liquid discharge head or a liquid discharge device, it is very difficult to realize a liquid discharge head or a liquid discharge device having a CMOS-integrated piezoelectric element that ensures the operation of the CMOS element and the liquid droplet discharge operation. A CMOS-integrated piezoelectric element refers to a structure in which a CMOS element and a piezoelectric element are arranged on the same substrate.

[0067] If the CMOS element can be manufactured on the same substrate as the piezoelectric element, the area of ​​electrode wiring and electrode mounting can be reduced, and the chip area of ​​the piezoelectric element can be significantly reduced. In this case, for example, the chip area of ​​the piezoelectric element is about 1 / 10. Since the number of components can also be reduced, a small, high-density, low-cost liquid discharge device can be provided by the piezoelectric method.

[0068] However, in order to obtain a piezoelectric element capable of discharging droplets with high driving force (high performance), a formation temperature of about 850°C is generally required, which destroys the previously formed CMOS element. Specifically, the destruction of CMOS elements refers to, for example, malfunction caused by threshold voltage shift of P-channel metal oxide semiconductor (PMOS) and N-channel metal oxide semiconductor (NMOS), dissolution of metal wiring, disconnection, cracking of the insulating layer, insulation breakdown, etc. On the contrary, when the formation temperature of the piezoelectric element is lower than the normal temperature, the piezoelectric element does not exhibit the desired piezoelectric performance (piezoelectric characteristics).

[0069] In order to form a CMOS element and a piezoelectric element on the same substrate, a suitable device is required, and the inventors have conducted in-depth research. When a piezoelectric element is formed after a CMOS element is formed, it is considered necessary to form the piezoelectric element at a formation temperature of, for example, 500°C or lower to avoid damage to the wiring (for example, metal wiring and interlayer insulating film) to the CMOS element. However, when a piezoelectric element is formed at such a formation temperature, the piezoelectric characteristics deteriorate.

[0070] Therefore, after forming the CMOS element, the piezoelectric element is formed at a formation temperature within a predetermined range before forming the CMOS wiring. When the manufacturing conditions are appropriately studied, a configuration is found that when the CMOS element and the piezoelectric element are formed on the same substrate, the desired CMOS action can be performed and excellent piezoelectric characteristics can be obtained.

[0071] In order to form CMOS elements and piezoelectric elements on the same substrate and realize better CMOS operation and excellent piezoelectric characteristics, it is necessary to design a manufacturing method. The details of the manufacturing method will be described later. In the manufacturing method of this embodiment, for example, measures such as changing the order of processes in the existing manufacturing method are taken. In the manufacturing method of this embodiment, after forming the CMOS element, the piezoelectric element is formed, and then the wiring to the CMOS element is formed. In this way, damage to the CMOS element and the wiring to the CMOS element can be avoided. In this manufacturing method, for example, the thickness of the insulating film produces a prescribed relationship.

[0072] The piezoelectric device of this embodiment is a piezoelectric device in which a CMOS element and a piezoelectric element are formed on the same substrate, the piezoelectric element has a lower electrode layer, a piezoelectric layer and an upper electrode layer, the substrate has a gap on the side opposite to the piezoelectric layer, sandwiching the lower electrode layer, the piezoelectric device has a first insulating film on the lower side of the lower electrode layer, and a second insulating film on the upper side of the upper electrode layer, and the first insulating film on the lower side of the piezoelectric layer is thinner than the second insulating film on the upper side of the piezoelectric layer.

[0073] According to this embodiment, a piezoelectric device having a CMOS element and a piezoelectric element on the same substrate and taking into account both CMOS operation and good piezoelectric characteristics can be provided. The piezoelectric device of this embodiment can ensure various characteristics of the CMOS element, and can obtain excellent piezoelectric characteristics with excellent driving force while maintaining the operation of the CMOS element.

[0074] Figure 1 This is a schematic diagram for explaining an example of the piezoelectric device according to the present embodiment.

[0075] In the piezoelectric device of this example, the CMOS element 120 and the piezoelectric element 160 are formed on the same silicon substrate 100. The silicon substrate 100 may be a P-type substrate or an N-type substrate. In this example, a P-type substrate is used.

[0076] The CMOS element 120 of this example includes an N well 111, a gate oxide film 113, a gate electrode 114, a source electrode 116a, a drain electrode 116b, and a substrate electrode 117. In this example, the CMOS element 120 and the wiring layer are distinguished, and a portion including the CMOS element 120 and a portion of the wiring layer is defined as a CMOS component 140.

[0077] The N-well 111 is a CMOS well. The CMOS well may be an N-well or a P-well. In this example, an N-well is used.

[0078] The field oxide film 112 is an element isolation insulating film. The CMOS element 120 may or may not include the field oxide film 112.

[0079] CMOS is formed by combining NMOS and PMOS. In the drawings of this embodiment, for the sake of convenience, only PMOS is shown, and parts related to NMOS are omitted.

[0080] The sidewall 115 is formed on the gate electrode 114. Figure 1 The side wall 115 is omitted. Fig.11E and 11F As shown in FIG11H, the gate electrode 114 is not subjected to impurity diffusion.

[0081] The source electrode 116a, the drain electrode 116b, and the substrate electrode 117 are formed, for example, by high-concentration impurity ion implantation, and may be referred to as an impurity diffusion layer, etc. In the drawings, the source electrode 116a and the drain electrode 116b may be reversed.

[0082] As the wiring layer, the figure shows a contact hole 132, a metal wiring 135, and an interlayer insulating film. The interlayer insulating film is formed between the metal wiring 135 and the metal wiring 135. The reference numeral of the interlayer insulating film is omitted here.

[0083] The wiring layer may have a multilayer structure, for example. For example, a contact hole, a first layer of metal wiring (metal 1), an interlayer insulating film (interlayer film 1), a through hole, a second layer of metal wiring (metal 2), ..., an interlayer insulating film (interlayer film n), a through hole, an nth layer of metal wiring (metal n), etc. may be sequentially formed to form a wiring layer. In this example, the metal wiring 135 includes two layers.

[0084] The contact hole 132 is provided for electrical contact with the gate electrode 114, the source electrode 116a, the drain electrode 116b, and the substrate electrode 117. The through hole is provided for electrical contact between metal wirings.

[0085] As the metal for wiring, for example, an aluminum-based material can be used. A copper-based material having low resistance and high temperature resistance can also be used. In this embodiment, there is no limitation, and other materials can also be used appropriately.

[0086] As the interlayer insulating film, a silicon oxide film by chemical vapor deposition (CVD) is generally used. A silicon nitride film having high moisture resistance is also often used as a substitute layer or an additional layer. In this embodiment, there is no particular limitation, and other films can be used as appropriate.

[0087] The piezoelectric element 160 of this example includes a lower electrode layer 161, a piezoelectric layer 162, and an upper electrode layer 163. The piezoelectric element 160 is connected to the CMOS element 120 via a metal wiring 135. In the drawings, the metal wiring 135 and the lower electrode layer 161 are connected to each other, but the metal wiring 135 and the upper electrode layer 163 may also be connected to each other.

[0088] In the figure, the displaceable portion 175 is indicated by a dotted line. The displaceable portion 175 is a region where the piezoelectric element 160 is not formed, and is a portion that is greatly deformed and displaced when a voltage is applied to the piezoelectric element 160. When the displaceable portion 175 is deformed, the vibration region 181 vibrates.

[0089] As the lower electrode layer 161 and the upper electrode layer 163, platinum (Pt) may be used, for example, but the present invention is not limited thereto, and a conductive metal material may be used. The lower electrode layer 161 and the upper electrode layer 163 may be made of the same material or different materials.

[0090] The lower electrode layer may be referred to as a first electrode, etc., and the upper electrode layer may be referred to as a second electrode, etc. The lower electrode layer may be a common electrode and the upper electrode layer may be a separate electrode, or the lower electrode layer may be a separate electrode and the upper electrode may be a separate electrode.

[0091] For example, lead zirconate titanate (PZT) or potassium sodium niobate (KNN) can be used for the piezoelectric layer 162. Preferably, PZT is used for the piezoelectric layer 162.

[0092] The method for forming the piezoelectric layer 162 is not particularly limited and can be appropriately selected. In the case of PZT, a sol-gel method or a sputtering method is generally used, and a chemical vapor deposition (CVD) method may also be used, but the method is not limited to these methods.

[0093] The silicon substrate 100 has a gap 190 on the side opposite to the piezoelectric layer 162 sandwiching the lower electrode layer 161. The provision of the gap 190 allows the vibration region 181 to vibrate. When the piezoelectric device is a liquid discharge head or a liquid discharge device, the gap 190 is a liquid chamber. The gap 190 is, for example, a cylindrical opening opened on the silicon substrate 100.

[0094] When a driving voltage is applied between lower electrode layer 161 and upper electrode layer 163, mechanical deformation occurs in piezoelectric layer 162. When a predetermined frequency of vibration is generated due to periodic changes in the driving voltage, vibration region 181 vibrates, generating ultrasonic waves or discharging liquid droplets in the case of a liquid discharge head.

[0095] The piezoelectric device of this embodiment may include a through hole penetrating the piezoelectric element 160 and communicating with the gap 190. In this case, the piezoelectric element 160 is formed around the through hole. When the piezoelectric device is a liquid discharge head, the through hole thus formed may be a nozzle hole for discharging liquid.

[0096] The piezoelectric device of this example includes a first insulating film 171 on the lower side of the lower electrode layer 161 and a second insulating film 172 on the upper side of the upper electrode layer 163. The first insulating film 171 below the piezoelectric layer 162 is thinner than the second insulating film 172 above the piezoelectric layer 162. The method of manufacturing the piezoelectric device will be described in detail later. In this embodiment, the CMOS element 120 and the piezoelectric element 160 are formed on the silicon substrate 100, and then the wiring layer is formed. By manufacturing in this order, the first insulating film 171 below the piezoelectric layer 162 becomes thinner than the second insulating film 172 above the piezoelectric layer 162. In order to clarify the position for comparing the thickness of the insulating film, it is defined as "below the piezoelectric layer" and "above the piezoelectric layer".

[0097] The manufacturing method of the piezoelectric device of the present embodiment is different from the existing manufacturing method of forming a piezoelectric element after forming a wiring layer for a CMOS element. In the manufacturing method of the piezoelectric element of the present embodiment, after forming the CMOS element, the piezoelectric element is formed, and then the wiring layer is formed. In the case of a manufacturing method such as the present embodiment, the reason why the second insulating film 172 (upper insulating film) is thicker than the first insulating film 171 (lower insulating film) is as follows. For example, the second insulating film 172 is manufactured to be several times thicker than the first insulating film 171.

[0098] When a CMOS element and a piezoelectric element are manufactured on the same substrate, and a wiring layer for the CMOS element is further formed after the piezoelectric element is formed, while an interlayer insulating film in the wiring layer for the CMOS element is formed, a layer for forming an interlayer insulating film is also formed on the piezoelectric element. Together with the protective insulating film of the piezoelectric element, the insulating film on the piezoelectric element becomes thicker. Therefore, in this embodiment, the second insulating film (upper insulating film) is thicker than the first insulating film (lower insulating film), in other words, the first insulating film is thinner than the second insulating film. This will be referred to later. Figures 3A to 5B To describe, when the vibration plate vibrates through the piezoelectric system, it is necessary to make one of the upper insulating film and the lower insulating film thicker (thinner). When they have the same thickness, vibration is impossible. Therefore, the first insulating film and the second insulating film have different thicknesses.

[0099] At this time, it is considered that vibration is possible by making the first insulating film thicker than the second insulating film. However, if the first insulating film is attempted to be thicker than the second insulating film, a layer for forming an interlayer insulating film is also formed on the piezoelectric element while forming an interlayer insulating film in the wiring layer for the CMOS element, so that the total thickness of the insulating film in the vibration area increases. Therefore, when the first insulating film is attempted to be thicker than the second insulating film, the total thickness of the insulating film in the vibration area increases, an excellent displacement amount cannot be ensured, and excellent piezoelectric characteristics cannot be obtained. In particular, in the case of a nozzle plate vibration system liquid discharge head, it is difficult to perform a good droplet discharge action.

[0100] The nozzle plate 251 (nozzle vibration plate) includes a first insulating film 171 (lower insulating film), a piezoelectric element 160, a second insulating film 172 (upper insulating film), and layers such as a resin layer on the second insulating film 172. In order to obtain desired vibration characteristics, it is preferable to precisely form the film thickness, rigidity, film stress, dimensions (for example, the width of the vibration plate, etc.) of each layer in advance, and perform design and manufacturing. In particular, the thickness of each layer is precisely controlled to obtain the desired vibration characteristics.

[0101] The first insulating film 171 and the second insulating film 172 can be appropriately selected, and for example, a silicon oxide film, a silicon nitride film, a stacked film of a silicon oxide film and a silicon nitride film, etc. can be used. As the first insulating film 171 and the second insulating film 172, for example, a silicon oxide film formed by a CVD method is generally used. A silicon nitride film having high moisture resistance is also often used as a substitute layer or an additional layer. In this embodiment, there is no particular limitation, and other films can be used appropriately.

[0102] The portion of the vibration region 181 including the first insulating film 171, the second insulating film 172, and the piezoelectric element 160 may be referred to as a vibration plate, etc. The vibration plate is a portion that affects the piezoelectric characteristics, and the piezoelectric characteristics are affected not only by the characteristics of the piezoelectric element 160 (piezoelectric characteristics, rigidity, various dimensions, etc.) but also by the film thickness and material of the first insulating film 171 and the second insulating film 172.

[0103] The piezoelectric device of this embodiment can be used not only for liquid discharge heads, but also for various purposes. Although this embodiment was obtained in the process of developing a liquid discharge device, the application scope of the technology of this embodiment is not limited to the liquid discharge device. The piezoelectric device of this embodiment can be made into a piezoelectric device with a higher driving force than that of a conventional piezoelectric device, and its application scope is not limited to the liquid discharge device. The piezoelectric device of this embodiment can be applied to various small devices, functional devices, and the like such as micro-infusion pumps that precisely transport small amounts of liquid, optical system (deflection) equipment such as projectors, ultrasonic (generation, detection, oscillation) system equipment, and hearing aids. In addition, for example, it can be applied to medical ultrasonic diagnostic equipment, etc.

[0104] Figure 2 FIG. 1 is a diagram showing another example of the piezoelectric element 160 in this embodiment.

[0105] In this example, the piezoelectric layer 162 is formed in a dome shape. In this example, the interlayer insulating layer 178 is provided on the upper side of the upper electrode layer 163. The second insulating film 172 also has a function of protecting the signal line 179. For example, the piezoelectric elements 160 are arranged in an array, and the individual piezoelectric elements 160 are electrically connected to each other through the signal line 179. In this example, the central axis of the piezoelectric element 160 is represented by O. The gap 190 is, for example, a cylindrical opening opened in the silicon substrate 100.

[0106] Thus, in this embodiment, the shape of the piezoelectric layer in the piezoelectric element can be appropriately changed. Figure 2 In the example shown, the first insulating film 171 is also thinner than the second insulating film 172 .

[0107] Figures 3A to 5B A diagram schematically showing vibration in a piezoelectric device.

[0108] First, we will describe Figure 3A and 3B In the drawings, a piezoelectric element 360 and a base layer 370 are schematically shown, and a vibration plate 380 includes the piezoelectric element 360 and the base layer 370, and the base layer 370 includes an insulating film. When a positive or negative voltage is applied between the upper electrode and the lower electrode of the piezoelectric element 360, compressive stress and tensile stress are generated in the piezoelectric element 360. In this way, the vibration plate 380 of the substrate is bent up and down by generating compressive stress and tensile stress.

[0109] Figure 3A The diagram schematically shows the situation in which compressive stress is generated, and the dotted line and arrow in the diagram schematically show the deformation direction of the vibration plate 380 . Figure 3B The situation in which tensile stress is generated is schematically shown. Figure 3A and 3B As shown, when the base layer 370 is located on the lower side of the piezoelectric element 360, when compressive stress is generated, the vibration plate 380 is deformed toward the upper side, and when tensile stress is generated, the vibration plate 380 is deformed toward the lower side.

[0110] Next, we will describe Figure 4A and 4B .exist Figure 4A and 4B In, with Figure 3A and 3B In contrast, the base layer 370 is disposed on the upper side of the piezoelectric element 360 . Figure 4A Schematic representation of the situation where compressive stress occurs, Figure 4B The situation in which tensile stress is generated is schematically shown. Figure 4A and 4B As shown, when the base layer 370 is located on the upper side of the piezoelectric element 360, when compressive stress is generated, the vibration plate 380 is deformed downward, and when tensile stress is generated, the vibration plate 380 is deformed upward.

[0111] Right now, Figure 3A and 3B And the vibration plates 380 in 4A and 4B are deformed in opposite directions. Figure 3A and 3B The vibration system shown in 4A and 4B is also called a vibration plate bending system, etc. The vibration plate bending system is a system in which a vibration plate (vibration area) is bent up and down by the displacement of the piezoelectric element included to be vibrated. In the present embodiment, such a vibration plate bending system is adopted. In the case of a vibration plate bending system as in the present embodiment, the direction of the vibration displacement changes according to the positional relationship between the base layer 370 of the vibration plate 380 and the piezoelectric element 360.

[0112] Next, we will describe Figure 5A and5B . Figure 5A and 5B Compare Figure 3A and 3B as well as Figure 4A and 4B The layer configuration of the piezoelectric element 160 is shown in more detail, showing the first insulating film 171 and the second insulating film 172. Figure 5A In the embodiment, the first insulating film 171 is thicker than the second insulating film 172, which is consistent with Figure 4A and 4B The situation where the middle substrate 370 is located on the lower side of the piezoelectric element 360 is similar. Figure 5B In the embodiment, the first insulating film 171 is thinner than the second insulating film 172, which is considered to be related to Figure 3A and 3B The case where the middle base layer 370 is located on the upper side of the piezoelectric element 360 is similar.

[0113] Figure 5A An example in which the first insulating film 171 is thicker than the second insulating film 172 is shown, but this example is not included in the present embodiment. Figure 5B This embodiment shows an example in which the first insulating film 171 included is thinner than the second insulating film 172 . Figure 5B The example shown corresponds to Figure 1 As described above, in the piezoelectric device according to the present embodiment, unlike the conventional manufacturing method, the second insulating film 172 (upper insulating film) is thicker than the first insulating film 171 (lower insulating film).

[0114] The displacement portion 175 shown by the dotted line in the figure is a portion that deforms more than other portions when driven (when bent). The configuration of the first insulating film 171, the piezoelectric element 160, the second insulating film 172 and the displacement portion 175 affects various vibration characteristics. A detailed description is omitted, and the design is performed taking into account the film thickness, stiffness, internal stress, various dimensions (width, length, shape, etc.) of the first insulating film 171, the piezoelectric element 160, the second insulating film 172 and the displacement portion 175. Studies have found that they significantly affect various vibration characteristics, and appropriate pre-design is required through simulation and short-circuit ring experiments.

[0115] When the vibration plate is vibrated by the piezoelectric system, one of the upper insulating film and the lower insulating film needs to be thickened (thinned). When they have the same thickness, vibration is impossible. Therefore, in Figures 3A to 5B In the process, one of the upper insulating film and the lower insulating film is made thicker (thinner).

[0116] [Liquid discharge head]

[0117] The piezoelectric device of this embodiment can be suitably applied to a liquid discharge head.

[0118] The liquid discharge head of this embodiment is provided with the piezoelectric device of this embodiment, and includes a through hole penetrating the piezoelectric element 160 and communicating with the space 190. The space 190 is supplied with liquid, and the through hole is a nozzle hole (nozzle) for discharging the liquid. The piezoelectric element 160 is formed around the nozzle hole.

[0119] According to this embodiment, a liquid discharge head can be obtained that includes a CMOS element and a piezoelectric element on the same substrate and realizes both CMOS action and droplet discharge action. The liquid discharge head of this embodiment can ensure various characteristics of the CMOS element and can obtain piezoelectric performance (driving force) that can discharge droplets while maintaining the action of the CMOS element.

[0120] Before describing an example of the liquid discharge head of the present embodiment, a discharge system in the liquid discharge head will be described. Fig. 6A and 6B This is a diagram for explaining the discharge principle of a piezoelectric system liquid discharge head. Fig. 6A is a schematic diagram for explaining the nozzle plate vibration system. Figure 6B is a schematic diagram for explaining a conventional exhaust system which is generally and widely used.

[0121] exist Fig. 6A In the example shown, the vibration plate 280 includes, for example, a piezoelectric element 260, a vibration plate base layer 270, and a nozzle 250. The piezoelectric element 260 is formed around the nozzle 250. Liquid (e.g., ink) flows into the individual liquid chambers 290 via the ink flow path 295. When the piezoelectric element 260 is driven, the vibration plate 280 moves as indicated by the arrows in the figure, and the ink in the individual liquid chambers 290 is discharged from the nozzle 250 as droplets.

[0122] Since the vibration plate 280 includes a nozzle, it can be called a nozzle plate or the like. Thus, since the vibration plate including the nozzle (nozzle plate) vibrates to discharge the liquid, Fig. 6A The discharge system in the example shown is called a nozzle plate vibration system or the like.

[0123] In contrast, Figure 6B In the conventional discharge system shown, the vibration plate 280 includes a vibration plate substrate 270 and a piezoelectric element 260 formed on the vibration plate substrate 270, but the nozzle 250 is not formed. The individual pressurized chamber 291 includes: a nozzle plate 251 (nozzle plate) formed with the nozzle 250; and the vibration plate 280 opposite to the nozzle plate 251. The ink is introduced into the individual pressurized chamber 291 through the fluid resistance 296.

[0124] In the conventional ejection system, as shown by the arrow in the figure, by applying a voltage (driving voltage) to the piezoelectric element 260 , the vibration plate 280 is vibrated to pressurize the ink in the individual pressurizing chambers 291 . As a result, the ink is ejected from the nozzles 250 .

[0125] In the existing discharge system, a large pressure is required to discharge the ink, and the piezoelectric element needs to have high piezoelectric performance (high driving force). Although bulk (solid) lead zirconate titanate (PZT) elements have been widely used for piezoelectric elements so far, in recent years, the piezoelectric performance of thin film PZT has been improved, and thin film PZT has been widely used. In recent years, it has been discovered that non-lead potassium sodium niobate (KNN) materials show very high piezoelectric properties and have begun to be used. Regarding the pressurization method of the ink, there are complex discharge mechanisms such as using pressure resonance, and their detailed description is omitted here.

[0126] in the past, Figure 6B The liquid discharge device of the conventional discharge system shown has been widely used, but Fig. 6A There are few examples of nozzle plate vibration systems that have been put into practical use and put on the market. The reason is unclear, but it is believed that there are many problems with the processability of bulk PZT, which is commonly used conventionally, and there are many problems with the electrode mounting when the piezoelectric element of PZT is located on the nozzle surface.

[0127] It is believed that the problem of PZT processability can be solved by the recent practical application of thin film PZT elements, and the problem of mounting electrodes can be solved by applying an improved method for mounting electrodes of a thermal head. It has been found that when thin film PZT elements and an improved method for mounting electrodes of a thermal head are applied Fig. 6A In the example shown, even if the Figure 6B In the example shown, a smaller driving force can also expel the droplets.

[0128] Specifically, for example, in Fig. 6A In the example shown, it has been confirmed that Figure 6B Compared with the example shown in the figure, even if the thickness of the vibration plate base layer 270 and the piezoelectric element 260 is thinned, the rigidity of the vibration plate 280 is greatly reduced, and the driving voltage applied to the piezoelectric element 260 is reduced to one tenth, the ink can be discharged. That is, compared with the conventional discharge method, even if the piezoelectric performance of the piezoelectric body is reduced to one tenth, the droplets can be ejected by the nozzle plate vibration method.

[0129] In the nozzle plate vibration system, since the nozzle plate including the nozzle directly vibrates, the inertial force of the fluid near the nozzle can be utilized, and therefore, it is considered that the ink can be discharged with a low driving force compared with the existing discharge system. The inventors of this embodiment confirmed through simulation and demonstration experiments that even when the driving force of the vibration plate in the nozzle plate vibration system is reduced to about one tenth of the driving force of the existing discharge system, droplets can be discharged. However, since there are still many unclear points in the discharge principle, a detailed description thereof is omitted here.

[0130] As described in the description of the piezoelectric device, it is necessary to appropriately try to form a CMOS element and a piezoelectric element on the same substrate, and the inventors of this embodiment have conducted in-depth research. The manufacturing method of the piezoelectric device of this embodiment is different from the existing manufacturing method of forming a piezoelectric element after forming a wiring layer for a CMOS element. In the method of manufacturing a piezoelectric device according to this embodiment, after forming a CMOS element, a piezoelectric element is formed, and then a wiring layer is formed. By doing so, a CMOS element and a piezoelectric element can be formed on the same substrate, CMOS action can be performed, and excellent piezoelectric characteristics can be obtained.

[0131] On the contrary, it was found that even when a piezoelectric device (a piezoelectric device capable of performing CMOS actions) in which a CMOS element and a piezoelectric element are formed on the same substrate is applied to a liquid discharge head, an excellent droplet discharge action cannot be performed by the existing discharge system. Therefore, an in-depth study was conducted, and it was found that the following conditions: forming a CMOS element, then, before forming the CMOS wiring, setting the formation temperature within a predetermined range, forming a piezoelectric element, and combining it with a nozzle plate vibration system can achieve the desired CMOS action and droplet discharge action. The specific content of the study is to use the formation temperature of the piezoelectric element as a parameter, and to study the relationship with the piezoelectric characteristics, and the relationship with the droplet discharge action in the nozzle plate vibration system. The results of this study will be described in the manufacturing method, embodiments, etc.

[0132] The liquid discharge head of the present embodiment includes a CMOS element and a piezoelectric element on the same substrate, and can achieve both a CMOS operation and an excellent liquid droplet discharge operation.

[0133] According to this embodiment, the advantages of the thermal system can be obtained while maintaining the advantages of the piezoelectric system. In the piezoelectric system, it is easy to obtain advantages such as high driving force (high viscosity, large droplets), high ink freedom, and high driving durability, but it was difficult to simultaneously obtain advantages of the thermal system such as small size, high density, and low cost. By realizing a liquid discharge head including a CMOS element and a piezoelectric element on the same substrate as in this embodiment, the above advantages can be obtained by further adopting a nozzle plate vibration system.

[0134] Figure 7 1 is a diagram showing an example of a liquid discharge head according to the present embodiment. Figure 1 The difference.

[0135] In this example, as shown in the figure, a through hole penetrating the piezoelectric element 160 and communicating with the space 190 is included, and the through hole is the nozzle hole 150 for discharging liquid. The space 190 supplied with liquid may be referred to as a liquid chamber, an individual liquid chamber, or the like.

[0136] The piezoelectric element 160 is formed around the nozzle hole 150. When the displacement portion 175 is deformed, the vibration region 181 vibrates. The portion of the vibration region 181 including the first insulating film 171, the second insulating film 172, and the piezoelectric element 160 may be referred to as a vibration plate or a nozzle plate. In this example, when the piezoelectric element 160 is driven, the nozzle plate vibrates, and liquid droplets are discharged from the nozzle hole 150. In this way, the liquid discharge head of this example discharges liquid droplets through the nozzle plate vibration system.

[0137] The vibration plate including the piezoelectric element 160 is a part that significantly affects the droplet discharge characteristics. The droplet discharge characteristics are affected not only by the characteristics of the piezoelectric element 160 (piezoelectric characteristics, rigidity, various dimensions, etc.), but also by the film thickness, material, etc. of the first insulating film 171 (lower insulating film) and the second insulating film 172 (upper insulating film).

[0138] Figure 8 FIG. 2 is a diagram showing another example of the liquid discharge head of the present embodiment. Figure 8 In the example shown, Figure 7 In the example shown, an ink contact film 176 (liquid contact film) and a nozzle water repellent film 177 (water repellent film) are provided. In this example, the silicon substrate 100 is provided with an ink contact film 176 at a portion in contact with liquid, and a nozzle water repellent film 177 is provided on the surface on the side where liquid is discharged.

[0139] The ink contact film 176 is provided at a location in contact with the liquid. The ink contact film 176 is provided, for example, in the flow path, for example, on the inner wall of the gap 190 (liquid chamber) or the inner wall of the nozzle hole 150. By providing the ink contact film 176, it is possible to prevent the dissolution of various materials caused by the contact of ink, the decrease in the adhesion between materials, and the like.

[0140] As the ink contact film 176, for example, a metal oxide film such as TaOx and HfOx having high liquid contact resistance (ink resistance) can be used. As the ink contact film 176, in addition to the above, a laminated film or a mixed film of the above metal oxide film and a silicon oxide film (SiOx) can also be used. In order to enable the ink to be smoothly introduced into the ink flow path, a material having a high lyophilic property (ink affinity, hydrophilicity) is more suitable, and the use of such a laminated film or a mixed film as the ink contact film 176 enables the ink to be smoothly introduced. Based on the above reasons, in the present embodiment, Ta is formed on the entire surface of the actuator by an atomic layer deposition (ALD) method. 2 O 5 and SiO 2 of mixed film.

[0141] In the case of the nozzle plate vibration method as in the present embodiment, the gap 190 does not need to be set as a closed space, and there is also an advantage of simplifying the device structure and method. Figure 6B As shown, in the conventional discharge system, in order to make the individual liquid chamber 291 (liquid chamber 291) a closed space, it is necessary to provide a fluid resistance 296 on the path between the individual liquid chamber 291 (liquid chamber). From this point of view, in the case of the nozzle plate vibration method as in the present embodiment, the device structure and method can be simplified.

[0142] In contrast, a closed space such as the conventional discharge method has the advantage of easily introducing ink by utilizing the capillary phenomenon. From this point of view, the nozzle plate vibration system may be disadvantageous in the introduction of ink in some cases. Considering this, it is preferable to use a lyophilic (ink-philic, hydrophilic) material as the ink contact film 176.

[0143] In this embodiment, a nozzle water-repellent film 177 (water-repellent film) is provided on the surface on the liquid discharge side. By using the nozzle water-repellent film 177, the water repellency of the surface on the liquid droplet discharge side of the nozzle plate can be enhanced, and the ink discharge capability can be improved. By using the nozzle water-repellent film 177, ink retention and ink adhesion on the nozzle plate surface can be prevented.

[0144] As the nozzle water-repellent film 177 , for example, a polymer material having high liquid repellency (ink repellency, water repellency) such as perfluorodecyltrichlorosilane (FDTS) or fluorotetrahydrooctyldimethylchlorosilane (FOTS) can be used.

[0145] In this example, FOTS is uniformly formed on the nozzle plate surface using the MVD method (molecular vapor deposition method). There are parts where this film is formed outside the nozzle plate surface (for example, inside the nozzle hole, inside the ink chamber), and sometimes measures are taken to remove this film, but a detailed description thereof is omitted here. Durability against mechanical stress during nozzle wiping (nozzle surface cleaning) is also required, so it is also important to obtain strong adhesion to the substrate.

[0146] As in this example, the liquid discharge head using the ink contact film 176 and the nozzle water-repellent film 177 has excellent ink filling properties (introducing ink into the ink flow path) and excellent ink contact durability. This also has stable and excellent ink discharge characteristics, keeps the nozzle plate surface clean and has high durability. In this example, a higher quality liquid discharge head can be obtained.

[0147] [Method of Manufacturing Piezoelectric Device and Method of Manufacturing Liquid Discharge Head]

[0148] Next, a method for manufacturing a piezoelectric device of the present embodiment and a method for manufacturing a liquid discharge head of the present embodiment will be described. The method for manufacturing a piezoelectric device of the present embodiment includes:

[0149] A CMOS element forming process is to form a CMOS element on a substrate;

[0150] A piezoelectric element forming step of forming a piezoelectric element on the substrate;

[0151] a wiring layer forming step of forming a wiring layer of the CMOS element and a wiring layer of the piezoelectric element; and

[0152] a cavity forming step of forming a cavity on the substrate,

[0153] The CMOS element and the piezoelectric element are formed on the same substrate.

[0154] In the CMOS element forming step or the piezoelectric element forming step, a first insulating film is formed in a region where the piezoelectric element is to be formed.

[0155] In the piezoelectric element forming step, a lower electrode layer, a piezoelectric layer, an upper electrode layer and a second insulating film are formed on the first insulating film.

[0156] In the cavity forming step, the cavity is formed on a side of the substrate opposite to the piezoelectric layer across the lower electrode layer.

[0157] The CMOS element forming step, the piezoelectric element forming step, the wiring layer forming step, and the gap forming step are performed in this order.

[0158] In the existing manufacturing method, when a CMOS element and a piezoelectric element are formed on the same substrate, when the piezoelectric element is formed, the wiring of the CMOS element (such as metal wiring and interlayer insulating film) is damaged, and the CMOS operation cannot be performed normally. When the piezoelectric element is formed after the CMOS element is formed, it is considered necessary to form the piezoelectric element at a formation temperature of, for example, 500°C or lower to avoid damaging the wiring of the CMOS element. However, when the piezoelectric element is formed at such a formation temperature, it is found that the piezoelectric characteristics are significantly deteriorated, and even the droplet discharge operation cannot be performed even by the nozzle plate vibration system.

[0159] In this embodiment, after forming a CMOS element on a substrate on which a nozzle hole for droplet discharge is formed, a piezoelectric element and wiring are formed in a suitable order under suitable conditions. As a result, a piezoelectric device including a CMOS element and a piezoelectric element on the same substrate and realizing both CMOS operation and excellent piezoelectric characteristics can be obtained.

[0160] According to this embodiment, a liquid discharge head can be provided that has the advantages of a piezoelectric system such as high output (high viscosity, large droplets), high ink freedom and high driving durability, and the advantages of a thermal system such as small size, high density and low cost.

[0161] Fig. 9 This is a flowchart for explaining an example of a method for manufacturing a piezoelectric device according to the present embodiment. In this example, a CMOS element forming step (S100), a piezoelectric element forming step (S110), a wiring layer forming step (S120), and a gap forming step (S130) are performed in this order. Other steps may also be performed as needed.

[0162] When forming a CMOS element and a piezoelectric element on the same substrate, it is necessary to consider the process management point of view to avoid contamination of the semiconductor production line by heavy metals, alkalis, etc. Therefore, it is necessary to form the CMOS element first and then form the piezoelectric element. Considering the above situation, the CMOS element forming process is performed first, and then the piezoelectric element forming process is performed.

[0163] When a piezoelectric element is formed on the same substrate as a CMOS element, it is necessary to form the piezoelectric element at a temperature lower than the formation temperature of the CMOS element in order to ensure the various characteristics of the CMOS element. Piezoelectric elements such as PZT thin film elements are usually formed at a temperature of about 850°C. When formed at a temperature lower than the formation temperature of the CMOS element (for example, 750°C), the piezoelectric characteristics (piezoelectric constant, piezoelectric displacement, and driving force) are significantly deteriorated.

[0164] Generally speaking, when manufacturing a CMOS integrated functional device, a part of the functional device is manufactured after forming the wiring to the CMOS element. However, usually, the wiring to the CMOS is mostly manufactured at a temperature of about 300°C to 400°C, and the highest temperature is about 500°C or less. Therefore, when the piezoelectric element is formed after the wiring to the CMOS element is formed, the wiring is damaged and the functional device cannot perform CMOS operation.

[0165] Although it varies depending on the material of the wiring to the CMOS element, the material of the interlayer insulating film, and the manufacturing method thereof, the wiring to the CMOS element is generally manufactured at about 350° C. in many cases. Therefore, when the piezoelectric element is formed after the wiring is formed, the piezoelectric element needs to be subjected to heat treatment with a light load of about 500° C. or less in order to prevent dissolution or disconnection of the wiring, cracking or insulation damage of the interlayer insulating film, etc. However, when the piezoelectric element is manufactured at a low temperature, excellent piezoelectric characteristics cannot be obtained.

[0166] Therefore, in this embodiment, by performing the wiring layer forming process after the piezoelectric element forming process, the forming temperature region of the piezoelectric body can be made higher than the forming temperature of the wiring layer forming process, and the process can be performed in a temperature region lower than the forming temperature of the CMOS element forming process. Therefore, the wiring layer forming process is performed after the piezoelectric element forming process.

[0167] In the manufacturing method of this embodiment, it is preferable to appropriately adjust the relationship between the formation temperature in the CMOS element formation step and the formation temperature in the piezoelectric element formation step.

[0168] The design rules and manufacturing processes of CMOS elements vary significantly depending on the requirements of the desired circuit. In the past, in CMOS operation, especially in the process of forming CMOS elements that affect the threshold voltage, the final high-temperature heating process (such as heat treatment for impurity diffusion) was mostly performed at 900°C for more than 30 minutes. After the CMOS element is formed, if the same or greater degree of heat treatment is applied, it will be difficult for the CMOS element to maintain various characteristics. For example, the threshold voltage of the CMOS element deviates significantly from the specification value, and the circuit no longer operates. Taking the above into consideration, the formation temperature of the piezoelectric element is also studied.

[0169] For example, in the piezoelectric element forming step, the piezoelectric element is preferably formed at a temperature lower than the temperature of the final high temperature heat treatment in the high temperature heat treatment for forming the CMOS element. This can prevent the degradation of the CMOS element.

[0170] In the high temperature heat treatment for forming the CMOS element, the final high temperature heat treatment can be appropriately selected, and for example, the final high temperature heat treatment that affects the CMOS characteristic value (threshold voltage, etc.), the final high temperature heat treatment that adjusts the CMOS characteristic value (threshold voltage, etc.), etc. In addition, in the high temperature heat treatment for forming the CMOS element, the final high temperature heat treatment includes a heat treatment for impurity diffusion when forming the source electrode and drain electrode of NMOS or PMOS in the CMOS element.

[0171] As the final high-temperature heat treatment in the high-temperature heat treatment for forming the CMOS element, for example, heat treatment for impurity diffusion when forming the source electrode and drain electrode of NMOS or PMOS in the CMOS element can be cited. Therefore, in the piezoelectric element forming step, it is preferable to form the piezoelectric element at a temperature lower than the impurity diffusion heat treatment temperature when forming the source electrode and drain electrode of NMOS or PMOS of the CMOS element. By setting it in this way, the degradation of the CMOS element can be prevented.

[0172] In the piezoelectric element forming process, it is more preferable to form the piezoelectric element at a temperature 100° C. or more lower than the temperature of the final high-temperature heat treatment (for example, heat treatment for impurity diffusion) performed in the CMOS element forming process. In this case, malfunction of the CMOS element can be more reliably prevented.

[0173] CMOS elements are usually formed at temperatures above 900°C. When a heat history of the same degree is applied after the CMOS is formed, the CMOS characteristics change (degrade). A particularly large impact is the change in threshold voltage. The results of the study found that when a piezoelectric element is formed at 750°C or lower after the CMOS element is formed, the threshold voltage remains almost unchanged. At a temperature about 100°C lower than the formation temperature of the CMOS element, for example 800°C, the threshold voltage changes slightly, but generally the operation is fine.

[0174] Therefore, as described above, it is more preferable to form the piezoelectric element at a temperature 100° C. or more lower than the temperature of the final high-temperature heat treatment (e.g., heat treatment for impurity diffusion) performed in the CMOS element formation process, more preferably at 750° C. or lower, and further preferably at 800° C. or lower. By doing so, it is possible to prevent CMOS operation from becoming defective.

[0175] In the piezoelectric element forming process, it is more preferred to form the piezoelectric element at a temperature of 500°C or higher. In this case, the piezoelectric characteristics can be prevented from being defective. In the piezoelectric element forming process, it is more preferred to form the piezoelectric element at a temperature of 500°C or higher and 800°C or lower. In this case, the CMOS operation can be prevented from being defective and the piezoelectric characteristics can be prevented from being defective.

[0176] Fig.10 This is an example of a flowchart for explaining that various characteristics vary depending on the conditions of the manufacturing method. In this flowchart, an example of the formation temperature of the piezoelectric element is described assuming the case of manufacturing a liquid discharge head.

[0177] First, a CMOS element forming step is performed (S100). As the next step, there is an option of forming a piezoelectric element before or after the wiring layer (S201). When the piezoelectric element is formed before the wiring layer, this is an example included in this embodiment.

[0178] When the piezoelectric element is formed before the wiring layer, the formation temperature of the piezoelectric element is appropriately adjusted. When the formation temperature of the piezoelectric element is 800°C or lower ("Yes" of S202) and 500°C or higher ("Yes" of S203), the liquid discharge head obtained by the piezoelectric element formation process A (S110a) and the wiring layer formation process (S120) can realize both CMOS action and droplet discharge action at a high level. This is a preferred example of (a).

[0179] When the formation temperature of the piezoelectric element is higher than 800°C ("No" of S202), the liquid discharge head obtained by the piezoelectric element formation step B (S110b) and the wiring layer formation step (S120) can realize both CMOS action and droplet discharge action, but the CMOS action is degraded. This is a poor example of (b). When the formation temperature of the piezoelectric element is higher than 800°C, it is considered that the CMOS element is affected.

[0180] When the formation temperature of the piezoelectric element is lower than 500°C ("No" in S203), the liquid discharge head obtained by the piezoelectric element formation process C (S110c) and the wiring layer formation process (S120) can realize both the CMOS action and the droplet discharge action, but the liquid discharge action is deteriorated. This is a poor example of (c). When the formation temperature of the piezoelectric element is lower than 500°C, it is considered that the piezoelectric element cannot be sufficiently heated, affecting the droplet discharge action.

[0181] In the case of "No" in S201, that is, when the wiring layer is formed before the piezoelectric element as in the prior art, this is a comparative example not included in the present embodiment. In this case, after the CMOS element is formed, the wiring to the CMOS element is formed (S210). Thereafter, the piezoelectric element is formed, and when the formation temperature of the piezoelectric element is 500°C or lower ("Yes" in S205), the droplet discharge action of the liquid discharge head obtained by the piezoelectric element formation process D (S110d) and the wiring layer formation process (S220) of the piezoelectric element becomes poor (d). This is because the formation temperature of the piezoelectric element is low, so that a piezoelectric element capable of obtaining an excellent droplet discharge action cannot be formed.

[0182] In the case of "No" in S201, when the formation temperature of the piezoelectric element is higher than 500°C (in the case of "No" in S205), the CMOS operation of the liquid discharge head obtained by the piezoelectric element formation step E (S110e) and the piezoelectric element wiring layer formation step (S220) becomes defective (e). This is because the formation temperature of the piezoelectric element is high, which deteriorates the CMOS element.

[0183] In the figure, the piezoelectric element forming steps A to E are different except for the forming temperature of the piezoelectric element.

[0184] The same process is performed. In the wiring layer forming step (S120) in the figure, wiring to the CMOS element and wiring to the piezoelectric element are formed.

[0185] In the manufacturing method of this embodiment, the first insulating film 171 is formed in the region where the piezoelectric body element 160 is formed, and the lower electrode layer 161, the piezoelectric body layer 162, the upper electrode layer 163, and the second insulating film 172 are formed on the first insulating film 171. As described above, since the CMOS element forming step, the piezoelectric body element forming step, the wiring layer forming step, and the gap forming step are performed in this order, the thickness of the first insulating film 171 (lower insulating film) below the piezoelectric body layer 162 is thinner than the thickness of the second insulating film 172 (upper insulating film) above the piezoelectric body layer 162.

[0186] The process of forming the first insulating film 171 may be included in the CMOS element forming process or the piezoelectric element forming process. In addition, the process of forming the first insulating film 171 may be used as another insulating film forming process, etc. Here, the process of forming the second insulating film 172 is set to be included in the piezoelectric element forming process, but it is not limited to this, and the process of forming the second insulating film 172 may be used as another insulating film forming process, etc.

[0187] In the piezoelectric element forming step, a method for forming the piezoelectric layer can be appropriately selected, and examples thereof include, for example, a sol-gel method, a sputtering method, and a chemical vapor deposition (CVD) method.

[0188] For example, when a PZT piezoelectric element is formed by a sol-gel method, it is generally formed by sintering at a temperature of about 850°C, but when formed at a temperature of 750°C or lower, the piezoelectric characteristics may deteriorate in some cases. However, in the case of a nozzle plate vibration system, sufficient droplet discharge characteristics can be obtained. Even in the case of formation by a sputtering method or a CVD method, when the formation temperature is lowered, deterioration of the piezoelectric characteristics is expected, however, in the case of a nozzle plate vibration system, sufficient droplet discharge characteristics can be obtained.

[0189] The method for manufacturing a piezoelectric device according to the present embodiment may include a process of forming a through hole that passes through the piezoelectric element 160 and communicates with the gap 190. The process of forming the through hole can be performed in the gap forming process, for example. When the piezoelectric device is applied to a liquid discharge head, the formed through hole can be set as the nozzle hole 150.

[0190] By forming the nozzle hole 150 penetrating the piezoelectric element 160, the piezoelectric element 160 is formed around the nozzle hole 150. As a result, a liquid discharge head of a nozzle plate vibration system can be obtained.

[0191] After the gap forming step, a liquid contact film and a water repellent film forming step may be performed to form a liquid contact film on a portion of the substrate that contacts the liquid and a water repellent film on a surface on the side where the liquid is discharged. Figure 8 By performing the steps of forming a liquid contact film and a water-repellent film, it is possible to prevent the dissolution of various materials and the deterioration of the adhesion between materials caused by ink contact, enhance the water repellency of the surface of the droplet discharge side of the nozzle plate, and obtain advantages such as improved ink discharge capability.

[0192] Examples of methods for manufacturing a piezoelectric device and a method for manufacturing a liquid discharge head

[0193] Below, we will refer to Figures 11A to 11H 12A to 12F describe examples of a method for manufacturing a piezoelectric device and a method for manufacturing a liquid discharge head.

[0194] Figures 11A to 11H 2 is a schematic diagram for explaining an example of a method for manufacturing a CMOS element. The example shown here is a general manufacturing method, and in this embodiment, a CMOS element can be formed using a general manufacturing method.

[0195] First, an active region in which a CMOS element is arranged is formed. Fig.11A and11B 1 shows a process of forming an N-well 111, a field oxide film 112, and a gate oxide film 113 on a silicon substrate 100. The field oxide film 112 is an element isolation oxide film. In some cases, a P-well may be formed instead of the N-well 111.

[0196] CMOS is formed by a combination of NMOS and PMOS, but for convenience only PMOS is shown in the figure, and CMOS related to NMOS is omitted. This process is not particularly limited, for example, it is performed at a thermal process of about 900°C or above, usually at 1000°C or above.

[0197] Fig. 11C 1 is a diagram for explaining the process of performing low-concentration impurity ion implantation for adjusting the threshold voltage of PMOS and NMOS. By performing low-concentration impurity ion implantation, a channel doping region 108 is formed. The arrows in the figure schematically represent the implantation of impurities. The channel doping region 108 is represented as a low-concentration impurity ion implantation region.

[0198] Fig.11D 2 shows a step of forming the gate electrode 104. The gate electrode 104 is formed by, for example, appropriately performing film formation, photolithography, etching, etc. Here, the detailed description of these steps is omitted.

[0199] Fig.11E 1 shows a step of forming the sidewall 115. The gate oxide film 113 is formed in a desired region.

[0200] Fig.11F 108b is a process for injecting high concentration impurity ions into the source region 106, the gate region 104a and the substrate electrode region 107. The arrows in the figure schematically indicate the injection of impurities. The source region 106, the gate electrode region 104a and the substrate electrode region 107 are indicated as impurity ion implantation regions. The channel doping region 108b is indicated as a low concentration impurity diffusion region.

[0201] Fig.11G Yes means to proceed Fig.11F 108c is a diagram showing the process of thermal diffusion and activation of high-concentration impurities implanted in the CMOS device (impurity diffusion heat treatment). This process is the final heat treatment process when forming a CMOS element. The channel doping region 108c is shown as a low-concentration impurity diffusion region.

[0202] Therefore, considering that until Fig.11G The thermal history of the process is used to design important CMOS characteristics (CMOS operation) such as threshold voltage, and to perform in accordance with process conditions. These processes require a thermal process of, for example, 800°C or above, and are mostly performed at around 900°C. Special attention should be paid to Fig.11GWhen forming a piezoelectric element after forming a CMOS element, it is preferable to form the piezoelectric element at a temperature lower than the temperature of the final heat treatment process so as not to affect various characteristics of the CMOS element. Fig.11G The temperature of the impurity diffusion heat treatment performed is performed at a low temperature.

[0203] Fig.11H This indicates a process of forming a layer used as an interlayer insulating film and a protective film after forming a CMOS element. This layer is the first insulating film 171. The process of forming the first insulating film 171 can be included in the CMOS element forming process or the piezoelectric element forming process. Fig. 12C Wiring to CMOS elements is performed.

[0204] As the first insulating film 171, a silicon oxide film by a CVD method is generally used. A silicon nitride film having high moisture resistance is also often used as a substitute layer or an additional layer. In this embodiment, there is no limitation, and other examples can be used appropriately.

[0205] The gate electrode 114 is shown as an active impurity diffusion region. The channel region 118 is set to a threshold voltage.

[0206] Fig. 12A It means execution Fig.11G A diagram of the state of Fig. 11B It means execution Fig.11H Here, it is described as a CMOS element 120, and the details of each part are the same as Figure 1 The contents shown are the same as above.

[0207] exist Fig. 12B , represents a first insulating film 171, which is also formed in a region where the piezoelectric element 160 is formed. The first insulating film 171 is a protective insulating film of the CMOS element and also serves as a lower insulating film of the piezoelectric element 160. Therefore, the first insulating film 171 is formed to have a film thickness and rigidity designed according to target vibration characteristics.

[0208] As the first insulating film 171, for example, a stacked film of a silicon oxide film and a silicon nitride film can be used. In this embodiment, since the structure of the insulating film can be appropriately selected, there is no limitation and it is shown in a simplified manner in the drawings.

[0209] Fig. 12C1 shows a process for forming the piezoelectric element 160 (piezoelectric forming process), and the figure shows a state where the piezoelectric element 160 is formed. In the piezoelectric element forming process, for example, the lower electrode layer 161, the piezoelectric layer 162, and the upper electrode layer 163 are formed in sequence, and then photolithography and patterning are performed in sequence. Since the detailed process of film formation and descent differs depending on the layout pattern of the piezoelectric element, the process concept, etc., it is not limited to this example.

[0210] Fig.12D 2 shows a step of forming the second insulating film 172. The second insulating film 172 serves as a protective insulating film for the piezoelectric element 160 and also serves as an interlayer insulating film on the CMOS element. Fig.12D In the illustrated state, the second insulating film 172 is the first interlayer insulating film on the CMOS element together with the previously formed first insulating film 171.

[0211] As the second insulating film 172, for example, a silicon oxide film can be used, but there is no limitation. The first insulating film 171 can be called a lower insulating film because it is provided on the lower side of the piezoelectric element 160, and the second insulating film 172 can be called an upper insulating film because it is provided on the upper side of the piezoelectric element 160.

[0212] Fig.12E 1 is a diagram showing the process of forming wiring (wiring layer forming process), and is a diagram showing the state of forming wiring. In this process, the processing of through holes, the film formation and processing of the first metal layer, the film formation of the interlayer insulating film layer, the processing of through holes, the film formation and processing of the second metal layer, and the film formation of the interlayer insulating film layer are performed in this order. For example, contact holes 132, first-layer metal wiring (metal 1), interlayer insulating film (interlayer film 1), through holes, second-layer metal wiring (metal 2), ..., interlayer insulating film (interlayer film n), through holes, n-th layer metal wiring (metal n), etc. are formed in sequence. Through the contact hole 132, electrical contact with the gate electrode 114, the source electrode 116a, the drain electrode 116b, and the substrate electrode 117 can be obtained, and through the through hole, electrical contact between metal wiring and metal wiring can be obtained.

[0213] In this example, the metal wiring 135 includes two layers, but the present embodiment is not limited thereto. According to the specifications of the required CMOS component, appropriate CMOS process design rules can be appropriately applied to the number and process of wiring layers. In this example, a stacked film of a silicon oxide film and a silicon nitride film is used as the uppermost interlayer insulating film.

[0214] As described above, the CMOS element and the piezoelectric element can be formed on the same substrate. Fig.12E In the illustrated state, a gap forming step is performed to form gap 190 , thereby manufacturing the piezoelectric device of this example.

[0215] The second insulating film 172 is an upper insulating film on the upper side of the piezoelectric element 160. The second insulating film 172 may have a stacked structure. For example, when the protective insulating film and the interlayer insulating film of the piezoelectric element are made of different materials, it can be said that the second insulating film 172 has a stacked structure. In this case, the second insulating film 172 includes the protective insulating film and the interlayer insulating film of the piezoelectric element.

[0216] The vibration plate (vibration region 181) is formed of, for example, the first insulating film 171, the piezoelectric element 160, and the second insulating film 172. In addition, a resin film (nozzle water repellent film, ink repellent film, etc.) may be further provided on the vibration plate. In order to obtain the desired vibration characteristics, it is preferred to precisely form the film thickness, rigidity, film stress, dimensions (for example, the width of the vibration plate, etc.) of each layer in advance, and perform design and manufacturing.

[0217] Fig.12F 1 is a diagram showing a state where the nozzle hole 150 and the gap 190 are formed. In this way, the liquid discharge head of this embodiment can be manufactured. This state is equivalent to the completion of the CMOS integrated piezoelectric element actuator. The liquid discharge device can be obtained by, for example, installing an ink introduction frame, an ink delivery system, etc.

[0218] [Liquid discharge device and liquid discharge apparatus]

[0219] Next, the liquid discharge device and the liquid discharge apparatus (liquid discharge apparatus) according to the present embodiment will be described. Fig.13 and 14 An example of the liquid discharge apparatus according to the present embodiment is described. Fig.13 It is a plan view of the main part of the liquid discharge device. Fig.14 It is a side view of the main part of the liquid discharge device.

[0220] The liquid discharge device is a serial type device, and the carriage 403 is reciprocated in the main scanning direction by the main scanning moving unit 493. The main scanning moving unit 493 includes a guide 401, a main scanning motor 405, a timing belt 408, etc. The guide 401 is bridged between the left side plate 491A and the right side plate 491B, and movably holds the carriage 403. The main scanning motor 405 reciprocates the carriage 403 in the main scanning direction through the timing belt 408 bridged between the driving pulley 406 and the driven pulley 407.

[0221] The liquid discharge device 440 is mounted on the carriage 403. The head 404 and the head tank 441 of the present embodiment integrally constitute the liquid discharge device 440. The head 404 of the liquid discharge device 440 discharges liquids of various colors, such as yellow (Y), cyan (C), magenta (M), and black (K). The head 404 includes a nozzle array including a plurality of nozzles 11 arranged in a row in a sub-scanning direction perpendicular to the main scanning direction. The head 404 is mounted on the carriage 403 so that ink droplets are discharged downward.

[0222] The liquid stored in the liquid box 450 is supplied to the head tank 441 through the supply unit 494 to supply the liquid stored outside the head 404 to the head 404 .

[0223] The supply unit 494 includes: a cartridge holder 451 serving as a filling portion to which the liquid cartridge 450 is mounted; a tube 456; a liquid supplier 452 including a liquid supply pump, etc. The liquid cartridge 450 is detachably connected to the cartridge holder 451. The liquid is supplied from the liquid cartridge 450 to the head tank 441 via the tube 456 by the liquid supplier 452.

[0224] The liquid discharge apparatus includes a conveyor 495 for conveying a sheet 410. The conveyor 495 includes a conveyor belt 412 as a conveyor and a sub-scanning motor 416 that drives the conveyor belt 412.

[0225] The conveyor belt 412 attracts the sheet 410 and conveys the sheet 410 to a position facing the head 404. The conveyor belt 412 is an endless belt stretched between a conveying roller 413 and a tension roller 414. The sheet 410 may be attracted to the conveyor belt 412 by electrostatic adsorption, air suction, or the like.

[0226] When the conveying roller 413 is rotationally driven by the sub-scanning motor 416 via the timing belt 417 and the timing pulley 418 , the conveying belt 412 rotationally moves in the sub-scanning direction.

[0227] On one side of the carriage 403 in the main scanning direction, a maintenance unit 420 for maintaining the head 404 in a good state is provided on the side of the conveying belt 412 .

[0228] The maintenance unit 420 includes, for example, a cap 421 for capping the nozzle face of the head 404 and a wiper 422 for wiping the nozzle face. The nozzle face is a surface of the head 404 on which a plurality of nozzles 11 are formed.

[0229] The main scanning moving unit 493, the supply unit 494, the maintenance unit 420, and the conveyor 495 are mounted to a housing including the side plate 491A, the side plate 491B, and the rear side plate 491C.

[0230] In the liquid discharge apparatus thus configured, the sheet 410 is fed onto the conveyor belt 412 , is sucked by the conveyor belt 412 , and is conveyed in the sub-scanning direction by the cyclic rotation of the conveyor belt 412 .

[0231] While the carriage 403 moves in the main scanning direction, the head 404 is driven in response to an image signal to discharge liquid toward the stopped sheet 410 , thereby forming an image on the sheet 410 .

[0232] In this manner, since the apparatus includes the liquid discharge head according to the present embodiment, a high-quality image can be stably formed.

[0233] Next, refer to Fig.15 Another example of the liquid discharge device 440 according to this embodiment will be described. Fig.15 This is a plan view of the main parts of another example of the liquid discharge device 440.

[0234] The liquid discharge device 440 includes, among the components of the liquid discharge apparatus, a housing, a main scanning moving portion 493, a carriage 403, and a head 404. The side plate 491A, the side plate 491B, and the rear side plate 491C constitute the housing.

[0235] In addition, the liquid discharge device 440 may be configured such that at least one of the maintenance unit 420 and the supply unit 494 is further mounted on, for example, the side plate 491B of the liquid discharge device 440 .

[0236] Next, refer to Fig.16 Another example of the liquid discharge device 440 according to this embodiment will be described. Fig.16 It is a front view of another example of the liquid discharge device 440.

[0237] The liquid discharge device 440 includes: a head 404, on which a flow path portion 444 is installed; and a tube 456, which is connected to the flow path portion 444.

[0238] The flow path portion 444 is disposed inside the cover 442. The liquid discharge device 440 may include a head tank 441 instead of the flow path portion 444. A connector 443 electrically connected to the head 404 is provided on the upper portion of the flow path portion 444.

[0239] The term "liquid discharge device" used herein also refers to a device including a liquid discharge head, a liquid discharge device, a head module, a head device, which discharges liquid by driving the head. The liquid discharge device can be, for example, a device capable of discharging liquid to a material to which the liquid can adhere, or a device capable of discharging liquid into a gas or a liquid.

[0240] The "liquid discharge device" may include a unit for supplying, conveying and spraying a material to which the liquid can adhere. The liquid discharge device may also include a pre-treatment device for applying the treatment liquid to the material, and a post-treatment device for applying the treatment liquid to the material, wherein the liquid has been discharged to the material.

[0241] The “liquid discharge device” may be, for example, an imaging device that forms an image on a sheet by discharging ink, or a three-dimensional modeling device that discharges modeling liquid into a powder layer in which a powder material is formed into multiple layers to form a three-dimensional modeled object.

[0242] The "liquid discharge device" is not limited to a device that discharges liquid to visualize a meaningful image such as letters or figures. For example, the liquid discharge device also includes a device for forming a pattern that itself has no meaning, or a device for making a three-dimensional image.

[0243] The above-mentioned "liquid-adhesive material" refers to a material to which liquid can at least temporarily adhere, and refers to a material to which liquid adheres and solidifies, a material to which liquid adheres and permeates, etc. Examples of the "liquid-adhesive material" include paper, recording paper, recording paper, film, cloth and other recording media, electronic substrates, piezoelectric elements and other electronic components, powder layers, organ models, inspection units and other media, and include all materials to which liquid adheres unless otherwise specified.

[0244] Examples of the above-mentioned "liquid-adhesive material" include paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, etc., including any material to which liquid can adhere even temporarily.

[0245] Examples of “liquid” include ink, processing liquid, DNA sample, resist, pattern material, adhesive, manufacturing liquid, and solution or dispersion containing amino acid, protein or calcium.

[0246] The "liquid discharge device" includes a device in which a liquid discharge head and a material to which liquid can be attached move relative to each other, but the liquid discharge device is not limited thereto. As specific examples, the liquid discharge device includes a serial type device that moves the liquid discharge head, a linear type device that does not move the liquid discharge head, and the like.

[0247] In addition, as "liquid discharge equipment", there are also processing liquid coating devices that coat the processing liquid on the surface of paper for the purpose of modifying the surface of the paper and discharge the processing liquid onto the paper, and jet granulation devices that granulate particles of the raw material by spraying a composite liquid obtained by dispersing the raw material in a solution through a nozzle, etc.

[0248] The "liquid discharge device" is an assembly of components related to liquid discharge. The "liquid discharge device" refers to a structure including a head and functional components or units coupled to the head to form a single unit. For example, the "liquid discharge device" includes a combination of a liquid discharge head and at least one of a head tank, a carriage, a supply unit, a maintenance unit, a main scanning moving unit, and a liquid circulation device.

[0249] Examples of a "single unit" include a combination in which a liquid discharge head and one or more functional parts and units are fixed to each other by, for example, fastening, bonding or joining, and a combination in which one of the liquid discharge head and the functional parts and units is movably held by the other. The liquid discharge head may be detachably connected to the functional part or unit.

[0250] For example, as the liquid discharge device 440, there are Fig.14 The head 404 and the head tank 441 are formed as one body of the liquid discharge device 440 shown in the figure. Alternatively, the head and the head tank connected by a tube or the like may be formed as one body of the liquid discharge device. A unit including a filter may be added between the head tank and the head of the liquid discharge device.

[0251] In another example, the head and carriage may form the liquid discharge device as a single unit.

[0252] In yet another example, the liquid discharge device includes a head movably held by a guide member forming a part of the main scanning moving unit, so that the head and the main scanning moving unit form a single unit. Fig.15 As in the liquid discharge device 440 shown in the figure, the head 404, the carriage 403, and the main scanning moving unit 493 are used as a unit to constitute the liquid discharge device 440.

[0253] In yet another example, a cover forming part of the maintenance unit may be secured to a carriage of the mounting head such that the head, carriage and maintenance unit form a single unit to form the liquid drainage arrangement.

[0254] and Fig.16 Similarly to the liquid discharge device 440 shown, the pipe 456 is connected to the head 404 or the flow path portion 444 to which the head tank 441 is attached, and the head 404 and the supply unit 494 (for example, the flow path portion 444 ) are integrated as the liquid discharge device 440 .

[0255] The main scanning moving unit may be only a guide. The supply unit may be only a tube or only a loading unit.

[0256] The pressure generator used in the "head" is not limited to a specific type of pressure generator. The pressure generator is not limited to the piezoelectric actuator (or stacked piezoelectric element) described in the above embodiment, and may be, for example, a thermal actuator using a thermoelectric conversion element such as a heating resistor, and an electrostatic actuator including a vibration plate and a relative electrode.

[0257] In the present disclosure, the terms “image formation”, “recording”, “printing”, “image printing”, “printing”, “modeling”, etc. are all synonyms.

[0258] [Example]

[0259] Hereinafter, the present embodiment will be described in more detail with reference to Examples, but the present embodiment is not limited to these Examples.

[0260] [Examples 1 to 9, Comparative Examples 1 to 15]

[0261] pass Figures 11A to 11C and Figures 12A to 12C The method shown is to manufacture Figure 7 The results are shown in Tables 1 and 2.

[0262] As the piezoelectric layer, PZT formed by the sol-gel method was used. The formation temperature of the CMOS element was set to 850°C and 900°C, and the formation temperature of PZT was used as a parameter for evaluation. The formation temperature of the CMOS element and the formation temperature of PZT are shown in Tables 1 and 2. Here, the formation temperature of the CMOS element is the temperature of the impurity diffusion heat treatment ( Fig.11G ) is the temperature of the final high-temperature heat treatment performed in the CMOS element formation process.

[0263] As shown in Tables 1 and 2, a nozzle plate vibration system ( Fig. 6A ) and the previous discharge system ( Figure 6B ) of the liquid discharge head.

[0264] [evaluate]

[0265] The operation of the CMOS element, the piezoelectric characteristics (displacement) of the piezoelectric element, the droplet ejection operation, and the compatibility between the CMOS operation and the ejection operation were evaluated.

[0266] [Operation of CMOS device]

[0267] The operation evaluation of the CMOS element is performed based on whether the CMOS circuit operates normally when both the CMOS circuit and the piezoelectric element are formed as in the present embodiment, similarly to the case where only the CMOS circuit is formed. Specific evaluation criteria are as follows.

[0268] Good: The threshold voltage deviation of each CMOS is within ±5%, and the specified CMOS circuit operates normally.

[0269] Acceptable: Although the threshold voltage of each CMOS shifts by ±5% or more, the specified CMOS circuit operates.

[0270] Bad: The specified CMOS circuit does not operate normally.

[0271] <Piezoelectric characteristics of piezoelectric elements (displacement)>

[0272] The piezoelectric characteristics of the piezoelectric element are evaluated based on whether the desired vibration plate displacement is obtained under a predetermined applied voltage. The evaluation criteria are as follows:

[0273] High: A displacement equal to or greater than the expected amount (significantly more than +20%) is achieved.

[0274] Middle: Obtain the desired displacement (±20%).

[0275] Low: The displacement is equal to or less than the expected displacement (less than -20%).

[0276] Low (Poor): The displacement is equal to or less than the expected displacement (significantly less than -20%).

[0277] <Droplet discharge operation>

[0278] The evaluation of the droplet discharge action is determined by whether a predetermined ink droplet (amount) can achieve a desired or higher ink discharge speed under a predetermined applied voltage. The evaluation criteria are as follows:

[0279] Good: Achieves expected or higher ink discharge rate (significantly more than +20%).

[0280] Acceptable: Achieve the desired ink discharge rate (±20%).

[0281] Poor: The ink discharge speed is equal to or lower than the expected ink discharge speed (significantly lower than -20%). Or no discharge.

[0282] <Compatibility of CMOS operation and ejection operation>

[0283] The evaluation criteria are as follows:

[0284] Good: Both CMOS element operation and droplet discharge operation are "good".

[0285] Acceptable: CMOS element action and droplet ejection action are "good" and "acceptable" respectively, or "acceptable" and "good" respectively.

[0286] Poor:Other (either one is "poor", or both are "poor")

[0287] [Table 1]

[0288]

[0289] [Table 2]

[0290]

[0291] Based on the above results, for example, it can be explained as follows.

[0292] Comparing Examples 1 to 4 with Comparative Examples 1 and 2, when the CMOS element formation temperature is 850°C, when the piezoelectric element formation temperature is in the range of 500°C to 750°C, the compatibility between the CMOS operation and the droplet discharge operation can be achieved by combining with the nozzle vibration plate system. As in Examples 2 and 3, when the piezoelectric element formation temperature is in the range of 600°C to 700°C, the compatibility between the CMOS operation and the droplet discharge operation is further improved.

[0293] Comparing Examples 5 to 9 with Comparative Example 3, when the CMOS element formation temperature is 900°C, when the piezoelectric element formation temperature is in the range of 500°C to 800°C, the compatibility between the CMOS operation and the droplet discharge operation can be achieved by combining with the nozzle vibration plate system. As in Examples 7 and 8, when the piezoelectric element formation temperature is in the range of 600°C to 750°C, the compatibility between the CMOS operation and the droplet discharge operation is further improved.

[0294] In Examples 4 and 9, the droplet discharge action was slow and a voltage higher than a predetermined voltage had to be applied, but since a stable compatible action was achieved, it was considered "acceptable".

[0295] The above-mentioned embodiments and comparative examples are examples of the results when verifying the liquid discharge head. As described in the above-mentioned embodiment, in the liquid discharge head of this embodiment, it is necessary that the formation temperature of the piezoelectric element meets the predetermined requirements and the piezoelectric element is a nozzle plate vibration system. In the liquid discharge heads obtained in comparative examples 1 to 5 and 10, the formation temperature of the piezoelectric element does not meet the prescribed conditions, and the liquid discharge heads obtained in other comparative examples use the conventional discharge method instead of the nozzle plate vibration method, so the compatibility between the CMOS operation and the discharge operation cannot be achieved.

[0296] When the piezoelectric device was verified, it was considered that the same tendency as the above-mentioned liquid discharge head could be obtained. When the piezoelectric device was manufactured under temperature conditions similar to those in the above-mentioned comparative examples 1 to 5 and 10, the examples included in this embodiment were obtained, and it was considered that both CMOS action and piezoelectric characteristics could be achieved. However, the CMOS action was at a barely acceptable level, which was worse than the other embodiments (for example, there was a non-acting part).

[0297] Aspects of this embodiment are, for example, as follows:

[0298] <1>

[0299] A piezoelectric device, comprising:

[0300] CMOS elements and piezoelectric elements formed on the same substrate;

[0301] The piezoelectric element includes a lower electrode layer, a piezoelectric layer and an upper electrode layer;

[0302] The substrate has a gap on a side opposite to the piezoelectric layer sandwiching the lower electrode layer;

[0303] The piezoelectric device includes a first insulating film on the lower side of the lower electrode layer and a second insulating film on the upper side of the upper electrode layer;

[0304] The first insulating film below the piezoelectric layer is thinner than the second insulating film above the piezoelectric layer.

[0305] <2>

[0306] The piezoelectric device according to <1>, wherein the piezoelectric element includes a piezoelectric layer, and the piezoelectric layer includes one or more selected from lead zirconate titanate (PZT) and potassium sodium niobate (KNN).

[0307] <3>

[0308] The piezoelectric device according to <1> or <2> comprises: a through hole that passes through the piezoelectric element and communicates with the gap, wherein the piezoelectric element is formed around the through hole.

[0309] <4>

[0310] A liquid discharge head includes the piezoelectric device according to <3>, wherein the gap is supplied with liquid, and the through hole is a nozzle hole for discharging the liquid.

[0311] <5>

[0312] The liquid discharge head according to <4>, wherein the substrate is provided with a liquid contact film at a portion in contact with the liquid, and a water repellent film is provided on a surface on a side on which the liquid is discharged.

[0313] <6>

[0314] A liquid discharge device, comprising: the liquid discharge head according to <4> or <5>.

[0315] <7>

[0316] A liquid discharge device according to <6>, wherein at least any one of a head tank for storing liquid supplied to the liquid discharge head, a slide for mounting the liquid discharge head, a supply unit for supplying the liquid to the liquid discharge head, a maintenance unit for maintaining the liquid discharge head in good condition, and a main scanning moving unit for moving the liquid discharge head in a main scanning direction is combined with the liquid discharge head to form a single unit.

[0317] <8>

[0318] A liquid discharge device, comprising: a liquid discharge head according to any one of <1> to <5> or a liquid discharge device according to <6> or <7>.

[0319] <9>

[0320] A method for manufacturing a piezoelectric device, the method comprising:

[0321] CMOS element forming process, forming a CMOS element on a substrate;

[0322] A piezoelectric element forming step of forming a piezoelectric element on the substrate;

[0323] A wiring layer forming step of forming a wiring layer of a CMOS element and a wiring layer of a piezoelectric element; and

[0324] a cavity forming step of forming a cavity in the substrate,

[0325] Among them, CMOS elements and piezoelectric elements are formed on the same substrate.

[0326] In a CMOS element forming step or a piezoelectric element forming step, a first insulating film is formed in a region where the piezoelectric element is to be formed.

[0327] In the piezoelectric element forming step, a lower electrode layer, a piezoelectric layer, an upper electrode layer, and a second insulating film are formed on the first insulating film.

[0328] In the cavity forming step, the cavity is formed on a side of the substrate opposite to the piezoelectric layer across the lower electrode layer.

[0329] The CMOS element forming step, the piezoelectric element forming step, the wiring layer forming step, and the gap forming step are performed in this order.

[0330] <10>

[0331] In the method for manufacturing a piezoelectric device according to <9>, the first insulating film below the piezoelectric layer is made thinner than the second insulating film above the piezoelectric layer.

[0332] <11>

[0333] A method for manufacturing a piezoelectric device according to <9> or <10>, wherein, in the piezoelectric element forming step, the piezoelectric element is formed at a temperature lower than the temperature of a heat treatment used for impurity diffusion when forming a source electrode and a drain electrode of an NMOS or PMOS in a CMOS element.

[0334] <12>

[0335] The method for manufacturing a piezoelectric device according to <11>, wherein in the piezoelectric element forming step, the piezoelectric element is formed at a temperature that is 100° C. or more lower than a temperature of a heat treatment for impurity diffusion.

[0336] <13>

[0337] The method for manufacturing a piezoelectric device according to <12>, wherein in the piezoelectric element forming step, the piezoelectric element is formed at a temperature of 800° C. or lower.

[0338] <14>

[0339] The method for manufacturing a piezoelectric device according to <12>, wherein in the piezoelectric element forming step, the piezoelectric element is formed at a temperature of 500° C. or higher.

[0340] <15>

[0341] The method for manufacturing a piezoelectric device according to any one of <9> to <14>, wherein in the piezoelectric element forming step, the piezoelectric layer is formed by a sol-gel method, a sputtering method, or a chemical vapor deposition (CVD) method.

[0342] <16>

[0343] In the method for manufacturing a piezoelectric device according to any one of <9> to <15>, in the cavity forming step, a through hole is formed that penetrates the piezoelectric element and communicates with the cavity.

[0344] <17>

[0345] A method for manufacturing a liquid discharge head, the method comprising: the method for manufacturing a piezoelectric device according to <16>, wherein the through hole is a nozzle hole for discharging liquid from the gap.

[0346] <18>

[0347] The method for manufacturing a liquid discharge head according to <17> further includes: after the gap forming process, forming a liquid contact film at the portion of the substrate in contact with the liquid, forming a water-repellent film on the surface of the side that discharges the liquid, and a liquid contact film and water-repellent film forming process.

[0348] [Aspect 1]

[0349] A method for manufacturing a piezoelectric device, the method comprising:

[0350] Forming a CMOS element on a first surface of the substrate;

[0351] A piezoelectric element is formed on the first surface of the substrate on which the CMOS element is formed;

[0352] When forming the CMOS element or the piezoelectric element, forming a first insulating film in a region where the piezoelectric element is to be formed;

[0353] When forming the piezoelectric element, a lower electrode layer, a piezoelectric layer, an upper electrode layer, and a second insulating film are formed on the first insulating film;

[0354] After forming the CMOS element and the piezoelectric element on the substrate, forming a CMOS wiring layer of the CMOS element and a piezoelectric wiring layer of the piezoelectric element; and

[0355] After the CMOS wiring layer and the piezoelectric wiring layer are formed on the substrate, a cavity is formed in the substrate from a second surface of the substrate opposite to the first surface.

[0356] [Aspect 2]

[0357] In the device manufacturing method according to aspect 1, the first insulating film is formed so that the first insulating film is thinner than the second insulating film and the first insulating film is closer to the first face of the substrate than the second insulating film.

[0358] [Aspect 3]

[0359] In the device manufacturing method according to aspect 1, further comprising:

[0360] performing heat treatment for impurity diffusion at a first temperature to form an NMOS source electrode and a drain electrode or a PMOS source electrode and a drain electrode in the CMOS element,

[0361] The piezoelectric element is formed at a second temperature lower than the first temperature of the heat treatment for impurity diffusion.

[0362] [Aspect 4]

[0363] In the device manufacturing method according to aspect 3, the second temperature is 100° C. or more lower than the first temperature.

[0364] [Aspect 5]

[0365] In the device manufacturing method according to aspect 4, the piezoelectric element is formed at the second temperature of 800° C. or lower.

[0366] [Aspect 6]

[0367] In the device manufacturing method according to aspect 5, the piezoelectric element is formed at the second temperature of 500° C. or higher and 800° C. or lower.

[0368] [Aspect 7]

[0369] In the device manufacturing method according to aspect 1, the piezoelectric element is formed using a sol-gel method, a sputtering method, or a chemical vapor deposition (CVD) method to form the piezoelectric layer.

[0370] [Aspect 8]

[0371] In the device manufacturing method according to aspect 1, it further includes: after forming the gap, a process of forming a through hole that penetrates the piezoelectric element and communicates with the gap.

[0372] [Aspect 9]

[0373] A head manufacturing method for manufacturing a liquid discharge head, the head manufacturing method comprising:

[0374] Execute the device manufacturing method according to aspect 8;

[0375] forming the gap on the substrate as a liquid chamber; and

[0376] The through hole serves as a nozzle hole, and the liquid in the liquid chamber is discharged from the nozzle hole.

[0377] [Aspect 10]

[0378] In the device manufacturing method according to aspect 9, further comprising:

[0379] forming a liquid contact film on the inner surface of the liquid chamber; and

[0380] A water-repellent film is formed on the nozzle surface where the nozzle hole is formed.

[0381] [Aspect 11]

[0382] A piezoelectric device, comprising:

[0383] A substrate having a void;

[0384] A CMOS element on a first surface of the substrate;

[0385] A first insulating film on the first surface of the substrate;

[0386] A piezoelectric element on the first insulating film, the piezoelectric element comprising:

[0387] A lower electrode layer having a first surface on the first insulating film;

[0388] A piezoelectric layer having a first surface on a second surface of the lower electrode layer opposite to the first surface; and

[0389] An upper electrode layer having a first surface on a second surface of the piezoelectric layer opposite to the first surface; and

[0390] A second insulating film is formed on the second surface of the upper electrode layer and has a thickness greater than that of the first insulating film.

[0391] [Aspect 12]

[0392] The piezoelectric device according to aspect 11 further comprises:

[0393] a through hole penetrating the piezoelectric element and communicating with the gap,

[0394] Wherein, the piezoelectric element surrounds the through hole.

[0395] [Aspect 13]

[0396] A liquid discharge head comprising:

[0397] The piezoelectric device according to claim 12,

[0398] wherein the gap has a liquid chamber for containing a liquid, and

[0399] The through hole has a nozzle hole from which the liquid in the liquid chamber is discharged.

[0400] [Aspect 14]

[0401] In the liquid discharge head according to aspect 13,

[0402] Wherein, the substrate comprises:

[0403] a liquid contact membrane on the inner surface of the liquid chamber, and

[0404] A water-repellent film on the nozzle face forming the nozzle hole.

[0405] [Aspect 15]

[0406] A liquid discharge device, comprising:

[0407] The liquid discharge head according to aspect 13; and

[0408] At least one of the following:

[0409] Head tank for supplying liquid to the liquid discharge head;

[0410] Mounting the liquid discharge head carriage;

[0411] A supply unit configured to supply the liquid to the liquid discharge head;

[0412] a maintenance unit configured to maintain the liquid discharge head; or

[0413] a main scanning moving unit configured to move the liquid discharge head in a main scanning direction,

[0414] Combined with the liquid discharge head to form a single unit.

[0415] The above embodiments are illustrative and do not limit the present invention. Therefore, many additional modifications and variations are possible based on the above teachings. For example, within the scope of the present invention, the components and / or features of the different illustrative embodiments may be combined with each other and / or replaced with each other. Any of the above operations may be performed in various other ways, such as in an order different from the above order.

[0416] This patent application is based on and claims the benefit of priority of Japanese Patent Application No. 2022-118758 filed with the Japan Patent Office on July 26, 2022, and the entire disclosure of which is incorporated herein by reference.

[0417] Reference numerals list

[0418] 100 Silicon substrate

[0419] 104 Gate electrode (no impurity diffusion)

[0420] 104a Impurity ion implantation region (gate electrode)

[0421] 106 Impurity ion implantation area (source electrode and drain electrode)

[0422] 107 Impurity ion implantation area (substrate electrode)

[0423] 108 channel doping region (low concentration impurity ion implantation region)

[0424] 108b channel doping region (low concentration impurity diffusion region)

[0425] 108c channel doping region (low concentration impurity diffusion region)

[0426] 110Main parts of CMOS components

[0427] Well 111

[0428] 112 Field Oxide Film

[0429] 113 Gate oxide film

[0430] 114 Gate electrode (impurity diffusion activation)

[0431] 115 side wall

[0432] 116a Source electrode

[0433] 116b Drain electrode

[0434] 117 substrate electrode

[0435] 118 Channel region (threshold voltage matching)

[0436] 120CMOS components

[0437] 132 through holes

[0438] 135 Metal wiring

[0439] 140CMOS components

[0440] 150 nozzle holes

[0441] 160 Piezoelectric element

[0442] 161 Lower electrode layer

[0443] 162 Piezoelectric layer

[0444] 163 Upper electrode layer

[0445] 171 first insulating film

[0446] 172 second insulating film

[0447] 175 Main displacement part of the vibration plate

[0448] 176 ink contact film

[0449] 177 Nozzle Water Repellent Film

[0450] 181 vibration area

[0451] 190 gap

[0452] 250 Nozzle

[0453] 251 Nozzle Plate

[0454] 260 Piezoelectric element (thin film piezoelectric element)

[0455] 270 vibration plate base

[0456] 280 vibration plate (all layers of vibration plate)

[0457] 290 Separation Chambers

[0458] 291 ink flow path (individual pressurized liquid chamber)

[0459] 295 ink flow path

[0460] 296 Ink flow path (fluid resistance)

[0461] 360 piezoelectric element layer (thin film piezoelectric element layer)

[0462] 370 vibration plate base

[0463] 380 vibration plate (all layers of vibration plate)

[0464] 385 Main displacement part of the vibration plate

[0465] Citation list

[0466] Patent Literature

[0467]

PTL1

Claims

1. A method for manufacturing a piezoelectric device, the method comprising: Forming a CMOS element on a first surface of the substrate; A piezoelectric element is formed on the first surface of the substrate on which the CMOS element is formed; When forming the CMOS element or the piezoelectric element, forming a first insulating film in a region where the piezoelectric element is to be formed; When forming the piezoelectric element, a lower electrode layer, a piezoelectric layer, an upper electrode layer, and a second insulating film are formed on the first insulating film; After forming the CMOS element and the piezoelectric element on the substrate, forming a CMOS wiring layer of the CMOS element and a piezoelectric wiring layer of the piezoelectric element; and After the CMOS wiring layer and the piezoelectric wiring layer are formed on the substrate, a cavity is formed in the substrate from a second surface of the substrate opposite to the first surface.

2. The method for manufacturing a device according to claim 1, in, forming the first insulating film so that the first insulating film is thinner than the second insulating film, and The first insulating film is closer to the first surface of the substrate than the second insulating film.

3. The method for manufacturing a device according to claim 1, further comprising: performing heat treatment for impurity diffusion at a first temperature to form an NMOS source electrode and a drain electrode or a PMOS source electrode and a drain electrode in the CMOS element, in, The piezoelectric element is formed at a second temperature lower than the first temperature of the heat treatment for impurity diffusion.

4. The method for manufacturing a device according to claim 3, in, The second temperature is 100° C. or more lower than the first temperature.

5. The method for manufacturing a device according to claim 4, in, The piezoelectric element is formed at the second temperature of 800° C. or less.

6. The method for manufacturing a device according to claim 5, in, The piezoelectric element is formed at the second temperature of 500° C. or higher and 800° C. or lower.

7. The method for manufacturing a device according to claim 1, in, The piezoelectric element is formed using a sol-gel method, a sputtering method, or a chemical vapor deposition (CVD) method to form a piezoelectric layer.

8. The method for manufacturing a device according to claim 1, further comprising: After forming the cavity, a step of forming a through hole that penetrates the piezoelectric element and communicates with the cavity.

9. A head manufacturing method for manufacturing a liquid discharge head, the head manufacturing method comprising: Execution of the device manufacturing method according to claim 8; forming the gap on the substrate as a liquid chamber; and The through hole serves as a nozzle hole, and the liquid in the liquid chamber is discharged from the nozzle hole.

10. The head manufacturing method according to claim 9, further comprising: forming a liquid contact film on the inner surface of the liquid chamber; and A water-repellent film is formed on the nozzle surface where the nozzle hole is formed.

11. A piezoelectric device comprising: A substrate having a void; A CMOS element on a first surface of the substrate; A first insulating film on the first surface of the substrate; A piezoelectric element on the first insulating film, the piezoelectric element comprising: A lower electrode layer having a first surface on the first insulating film; A piezoelectric layer having a first surface on a second surface of the lower electrode layer opposite to the first surface; and An upper electrode layer having a first surface on a second surface of the piezoelectric layer opposite to the first surface; and A second insulating film is formed on the second surface of the upper electrode layer and has a thickness greater than that of the first insulating film.

12. The piezoelectric device according to claim 11, further comprising: a through hole penetrating the piezoelectric element and communicating with the gap, in, The piezoelectric element surrounds the through hole.

13. A liquid discharge head comprising: The piezoelectric device according to claim 12, in, The void has a liquid chamber for containing a liquid, and The through hole has a nozzle hole from which the liquid in the liquid chamber is discharged.

14. The liquid discharge head according to claim 13, in, The substrate comprises: a liquid contact membrane on the inner surface of the liquid chamber, and A water-repellent film on the nozzle face forming the nozzle hole.

15. A liquid discharge device comprising: A liquid discharge head according to claim 13; and At least one of the following: Head tank for supplying liquid to the liquid discharge head; Mounting the liquid discharge head carriage; A supply unit configured to supply the liquid to the liquid discharge head; a maintenance unit configured to maintain the liquid discharge head; or a main scanning moving unit configured to move the liquid discharge head in a main scanning direction, Combined with the liquid discharge head to form a single unit.

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