Substrate for liquid ejection head, liquid ejection head, and recording device

Abstract

The present invention provides a recording element substrate for a liquid ejection head that prevents ink dissolution from progressing even if the heater element is disconnected and ink enters, without relying on the barrier metal layer in the through-hole section. [Solution] The recording element substrate for a liquid ejection head of the present disclosure includes a heater layer on which a plurality of heaters are formed, a wiring layer on which common wiring electrically connected to the plurality of heaters is formed, and a cavitation-resistant layer laminated in a first direction relative to the heater layer, wherein the substrate comprises a first common wiring which is a common wiring for supplying voltage from the outside, and a first plug which extends from the heater layer in the opposite direction to the first direction and supplies voltage to the heater by filling the inside of a through-hole directly connected to the heater with a conductive material, and the first common wiring and the first plug are electrically connected via wiring formed of the same material as the cavitation-resistant layer.

Description

Technical Field

[0001] The present disclosure relates to a substrate for a liquid ejection head, a liquid ejection head, and a recording apparatus for ejecting ink by a liquid ejection method to perform recording on a recording medium.

Background Art

[0002] Inkjet recording heads (hereinafter referred to as recording heads) are known to form ink droplets ejected by various methods. Among them, a recording head using a method that utilizes heat from a heater for ink ejection can relatively easily achieve high-density multi-nozzle formation and enables high-speed recording with high resolution and high image quality.

[0003] When a plurality of heaters are simultaneously driven for recording, the voltage drop due to wiring varies depending on the number of heaters driven simultaneously, and it is known that the energy supplied to the heaters fluctuates depending on the number of simultaneous drives, resulting in a decrease in ejection stability. To solve this problem, an inkjet recording head uses a common wiring in which the wiring layer connected to the heater is thickened and the width is made as wide as possible for the purpose of reducing the resistance of the wiring that causes the voltage drop.

[0004] In an inkjet recording head, an overcurrent may flow through the heater element due to the generation of abnormal pulses such as noise, resulting in an unexpected disconnection of the heater element on the recording element substrate. Since the periphery of the heater element is exposed to ink, when the heater element is disconnected, the wiring connected to the heater is exposed to the ink. On the other hand, in order to drive other normal heater elements, a voltage is supplied to the common wiring, and melting of the wiring starting from the disconnected heater element occurs. If this state continues, the melting of the wiring reaches the wiring of adjacent heater elements, and the heater elements stop functioning collectively starting from the disconnected heater element. In recent years, a technique for detecting a disconnected heater element and complementing it with other normal heater elements has been introduced, but when the heater elements stop functioning collectively, it becomes difficult to complement them with other normal heater elements, leading to a decrease in image quality.

[0005] To prevent the spread of wire breakage due to the melting of such wiring, Patent Document 1 proposes an inkjet recording head in which the wires pass through through-holes with a low aspect ratio (through-hole height / through-hole diameter) where the barrier metal is sufficiently covered. With this configuration, individual wires connected to the heater element pass through through-holes with good coverage of the barrier metal layer before being connected to the power supply wiring. Therefore, even if a wire breaks and the tungsten melts due to the ink, the barrier metal layer can suppress the progression of the melting. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-179527 [Overview of the project] [Problems that the invention aims to solve]

[0007] As semiconductor technology becomes more densely densified, through-hole diameters are also becoming smaller along with the miniaturization of wiring. Furthermore, to reduce wiring resistance and thus voltage drop, it is preferable to increase the thickness of the wiring film. However, as the wiring layer becomes thicker, the thickness of the interlayer insulating film also increases, and the height of the through-holes also increases. Against this backdrop, the aspect ratio of through-holes tends to increase, and the coverage of the barrier metal layer at the bottom of the plug tends to deteriorate. Prior art document 1 discloses a configuration in which the barrier metal layer of the plug prevents the wiring from dissolving. However, as the aspect ratio increases further, the barrier metal layer may not adequately cover the wiring, and ink may penetrate through the insufficiently covered areas, potentially leading to the dissolution of the wiring. In other words, the configuration in prior art document 1 cannot be applied to semiconductor manufacturing processes that do not have a sufficiently low through-hole aspect ratio to prevent ink dissolution. [Means for solving the problem]

[0008] To solve the above problems, a recording element substrate for a liquid ejection head according to one embodiment of the present disclosure is A recording element substrate for a liquid ejection head includes a heater layer on which a plurality of heaters are formed, a wiring layer on which common wiring electrically connected to the plurality of heaters is formed, and a cavitation-resistant layer laminated in a first direction relative to the heater layer, wherein the common wiring is a first common wiring for supplying voltage from the outside, and a first plug extends from the heater layer in the opposite direction to the first direction and supplies voltage to the heater by filling the inside of a through-hole directly connected to the heater with a conductive material, and the first common wiring and the first plug are electrically connected via wiring formed of the same material as the cavitation-resistant layer. [Effects of the Invention]

[0009] The heating element has excellent ink resistance, and the wiring layer, which forms a common wiring that electrically connects to multiple heaters, is electrically connected to the heating element layer, which has a sufficiently coated cavitation-resistant layer. This prevents the progression of ink dissolution and prevents the spread of wire breakage to adjacent heaters in the event of a break. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing a schematic configuration of a recording device equipped with a recording head, which is a typical embodiment of the present disclosure. [Figure 2] This block diagram shows the control configuration of the recording device shown in Figure 1. [Figure 3] This diagram shows the layout configuration of the element substrate (head substrate) mounted on the recording head. [Figure 4] Figure 3 is a magnified view of the X portion of the element substrate shown in Figure 3. [Figure 5] This diagram shows the equivalent circuit of a drive circuit that drives a single heater. [Figure 6] This is a cross-sectional view showing the multilayer structure of an element substrate according to the first embodiment. [Figure 7] This is a partial top view of the element substrate when the cavitation-resistant wiring 361 is individual wiring. [Figure 8] This is a partial top view of the element substrate when the cavitation-resistant wiring 361 is a common wiring. [Figure 9] This is a cross-sectional view showing the multilayer structure of an element substrate according to the second embodiment. [Figure 10] (a) This diagram shows the coverage of the barrier metal layer when the aspect ratio of the through-hole is large. (b) This diagram shows the coverage of the barrier metal layer when the aspect ratio of the through-hole is small. [Figure 11] This is a schematic cross-sectional view illustrating the dissolution process when the aspect ratio of the through-hole is high. [Figure 12] (a) A schematic top view showing the initial melting process of the device substrate when the through-hole aspect ratio is high. (b) A schematic top view showing the device substrate after melting has progressed when the through-hole aspect ratio is high. [Figure 13] This is a cross-sectional view showing the multilayer structure of a conventional device substrate. [Figure 14] This diagram schematically shows how the plug melted due to a break in the wiring of the element substrate in the first embodiment. [Modes for carrying out the invention]

[0011] Preferred embodiments of this disclosure will be described in more specific and detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0012] In this specification, "record" (sometimes referred to as "print") refers not only to cases where meaningful information such as text and figures is formed, but also to cases where images, patterns, etc. are formed on a recording medium, or where the medium is processed, regardless of whether it is meaningful or not.

[0013] In addition, the “recording medium” shall represent not only paper used in general recording devices, but also, broadly, materials such as cloth, plastic film, metal plates, glass, ceramics, wood, leather, etc. that can receive ink.

[0014] Furthermore, “ink” (sometimes referred to as “liquid”) shall be interpreted as broadly as the above definition of “recording (printing)”. Therefore, it represents a liquid that can be used for forming images, patterns, etc. on a recording medium, or processing the recording medium, or processing the ink (for example, coagulating or insolubilizing the colorant in the ink applied to the recording medium) by being applied onto the recording medium.

[0015] Moreover, “nozzle” shall generally refer to a discharge port, a liquid passage communicating therewith, and an element that generates energy used for ink discharge, unless otherwise specified.

[0016] The element substrate (head substrate) for a recording head used hereinafter does not simply refer to a mere substrate made of silicon semiconductor, but indicates a configuration provided with various elements, wirings, etc.

[0017] Furthermore, “on the substrate” not only simply indicates above the element substrate, but also indicates the surface of the element substrate and the inner side of the element substrate near the surface. Also, “built-in” as used in the present disclosure does not refer to simply arranging each separate element as a separate entity on the substrate surface, but indicates integrally forming and manufacturing each element on the element board by a semiconductor circuit manufacturing process or the like.

[0018] <Overview of the recording device> FIG. 1 is an external perspective view showing an overview of the configuration of a recording device that performs recording using an inkjet recording head (hereinafter referred to as the recording head), which is a representative embodiment of the present disclosure.

[0019] As shown in Figure 1, the inkjet recording device (hereinafter referred to as the recording device) 1 has an inkjet recording head (hereinafter referred to as the recording head) 3 mounted on a carriage 2, which ejects ink according to the inkjet method to perform recording. The carriage 2 is then moved back and forth in the direction of arrow A to perform recording. A recording medium P, such as recording paper, is fed via a paper feeding mechanism 5, transported to the recording position, and at that recording position, ink is ejected from the recording head 3 onto the recording medium P to perform recording.

[0020] The carriage 2 of the recording device 1 not only mounts a recording head 3, but also has an ink tank 6 attached to it for storing the ink supplied to the recording head 3. The ink tank 6 is detachable from the carriage 2.

[0021] The recording device 1 shown in Figure 1 is capable of color recording, and for this purpose, the carriage 2 is equipped with four ink cartridges, each containing magenta (M), cyan (C), yellow (Y), and black (K) inks. These four ink cartridges can be attached and detached independently.

[0022] The recording head 3 in this embodiment employs an inkjet method that uses thermal energy to eject ink. For this purpose, it is equipped with an electrothermal conversion element (heater). Each of these electrothermal conversion elements is provided corresponding to one of the ejection ports, and by applying a pulse voltage to the corresponding electrothermal conversion element in accordance with the recording signal, ink is ejected from the corresponding ejection port. Note that the recording device 1 is not limited to the serial type recording device described above, but can also be applied to a so-called full-line type recording device in which a recording head (line head) with ejection ports arranged in the width direction of the recording medium is positioned in the transport direction of the recording medium.

[0023] Figure 2 is a block diagram showing the control configuration of the recording device shown in Figure 1. As shown in Figure 2, the controller 600 consists of an MPU 601, a ROM 602, a special-purpose integrated circuit (ASIC) 603, a RAM 604, a system bus 605, an A / D converter 606, and the like. Here, the ROM 602 stores a program corresponding to the control sequence described later, required tables, and other fixed data. The ASIC 603 generates control signals for controlling the carriage motor M1, the transport motor M2, and the recording head 3. The RAM 604 is used as an area for expanding image data and a working area for program execution. The system bus 605 connects the MPU 601, ASIC 603, and RAM 604 to exchange data. The A / D converter 606 receives analog signals from the sensor group described below, performs A / D conversion, and supplies the digital signal to the MPU 601.

[0024] In Figure 2, 610 is a host device corresponding to a host or MFP that serves as the source of image data. Image data, commands, status, etc. are transmitted and received between the host device 610 and the recording device 1 via packet communication through interface (I / F) 611. Furthermore, a USB interface may be provided as interface 611 in addition to the network interface, allowing for the reception of bit data and raster data transmitted serially from the host.

[0025] Furthermore, 620 is a group of switches, consisting of a power switch 621, a print switch 622, a recovery switch 623, and so on.

[0026] 630 is a group of sensors for detecting the device status, and consists of a position sensor 631, a temperature sensor 632, etc. In this embodiment, a photosensor for detecting the ink level is also provided.

[0027] Furthermore, 640 is a carriage motor driver that drives the carriage motor M1 for scanning the carriage 2 back and forth in the direction of arrow A, and 642 is a transport motor driver that drives the transport motor M2 for transporting the recording medium P.

[0028] During recording scanning by the recording head 3, the ASIC 603 directly accesses the memory area of ​​the RAM 604 and transfers data to the recording head to drive the heating element (ink ejection heater). In addition, this recording device is equipped with a display unit consisting of an LCD and LEDs as a user interface.

[0029] Figure 3 is a plan view showing the layout configuration of the element substrate 700 mounted on the recording head 3. The element substrate 700 shown in Figure 3 has a rectangular shape, and multiple pads 450 are provided along the long side of the rectangular plane of the element substrate 700, through which data and drive voltage are supplied from the outside (the main body of the recording device). Multiple heaters 350, multiple ink supply ports 550, and multiple switching elements 510 are arranged along the long side of the element substrate 700.

[0030] In the example shown in Figure 3, four sets of heater rows (350), ink supply port rows (550), and switching element rows (510) are provided. Each of these sets is used for recording using magenta (M), cyan (C), yellow (Y), and black (K) inks, respectively.

[0031] Figure 4 is an enlarged view of section X shown in Figure 3. As shown in Figure 4, each heater 350 is provided with an ink ejection port 420 from which ink droplets are ejected. Ink supply ports 550, associated with each heater, are provided on both sides of the row of ejection ports.

[0032] Figure 5 shows an equivalent circuit of a drive circuit that drives one heater. As shown in Figure 5, one connection 341 of the heater (heating resistor) 350 is electrically connected to the VH common wiring 131 for supplying voltage. Furthermore, the other connection 342 of the heater 350 is electrically connected to the GND common wiring 141 via a switching element 510 (driver) for switching the drive of the heater 350 on and off. In this embodiment, the switching element 510 is a MOSFET, and the heater 350 is driven by switching it on and off by applying an external drive voltage to the gate of the MOSFET.

[0033] Next, we will describe an example of an element substrate mounted on the recording head of the recording device with the above configuration. Here, we will first describe a conventional element substrate configuration as a comparative example, and then describe the characteristics of the element substrate according to this example.

[0034] <Explanation of the manufacturing method of recording element substrates and its challenges> Figure 13 is a cross-sectional view showing the multilayer structure of a conventional element substrate as a comparative example. This cross-sectional view is the B-B' cross-sectional view shown in Figure 4. As shown in Figure 13, a Poly-Si layer 100, wiring layers 110, 120, 130, 140, a heater 350, and a cavitation-resistant layer 360 are deposited on a Si substrate 530 along a first direction. In Figure 13, the Si substrate 530 side is the lower side in the first direction, and the discharge port 420 side is the upper side in the first direction. Each wiring layer is insulated from each other by insulating layers 200, 210, 220, 230, 240, and 250. In addition, through-holes 300, 310, 320, 330, and 340 are formed extending in the first direction and penetrating the insulating layers in order to electrically connect each wiring.

[0035] Next, we will explain the differences depending on the aspect ratio of the through-hole when ink penetrates the wiring and through-holes during a wire break. Figure 10 shows the coverage of the barrier metal layer depending on the aspect ratio of the through-holes for the plug. Plugs are generally made of tungsten (W) (721, 711), and the barrier metal layer (722, 712) is made of a material containing titanium (Ti), for example, TiN, with a thickness of 10 nm to 30 nm. TiN is a material that is widely used in semiconductor device substrates as a diffusion prevention film and adhesion film, and it also has high corrosion resistance. Therefore, even if ink penetrates into the inside of the device substrate and the aluminum alloy wiring material or the tungsten plug dissolves and corrodes in the ink, the titanium nitride film remains uncorroded.

[0036] Thus, the titanium nitride film is formed to surround the metal plug as a barrier metal layer. However, when depositing titanium nitride using the sputtering method, the titanium nitride film is not always uniformly deposited at the bottom of the through-hole formed by penetrating the insulating layer. As a result, there may be areas where the barrier metal layer does not adequately cover the metal plug. In particular, the larger the aspect ratio of the through-hole (through-hole height / through-hole diameter), the more difficult it becomes for the film-depositing material to reach the bottom of the through-hole, making it difficult to obtain adequate coverage.

[0037] For example, if a through-hole is formed with a height of 0.6 μm and a diameter of 0.4 μm, the aspect ratio will be 0.6 / 0.4 = 1.5. An aspect ratio of 1.5 indicates good barrier metal coverage. On the other hand, if a through-hole is formed with a height of 1.4 μm and a diameter of 0.6 μm, the aspect ratio will be 1.4 / 0.6 = 2.333. When the aspect ratio is greater than 2, it becomes difficult to obtain sufficient coverage of the barrier metal layer at the corners of the through-hole.

[0038] On the other hand, when heater element circuits and other components are arranged at high density, the wiring is miniaturized, and the through-hole diameter is also miniaturized. Furthermore, to reduce wiring resistance in order to reduce voltage drop, it is preferable to increase the thickness of the wiring layer. However, as the thickness of the wiring layer increases, the thickness of the interlayer insulating film also increases, and the height of the through-hole also increases. Due to these factors, the aspect ratio of the through-hole tends to increase, and the coverage of the barrier metal layer tends to deteriorate at the corners 723 at the bottom of the through-hole. In Figure 10(a), the through-hole height is greater than in (b), and the barrier metal layer 722 tends to become thinner towards the bottom. In general sputter deposition methods, if the deposition time is extended, the barrier metal layer becomes thicker in flat areas, but it is difficult to significantly improve the film thickness in areas where the deposition material is difficult to reach, such as the bottom of the through-hole.

[0039] Therefore, when a wire breaks, melting progresses from the area where the barrier metal layer at the corner of the through-hole has poor coverage, as shown in Figure 11. If this melting progresses to the power supply wiring of the adjacent heater element, as shown in Figure 12(b), the adjacent heater element will also cease to function.

[0040] Next, an embodiment of the element substrate mounted on the recording head of the recording device of this disclosure will be described.

[0041] (First Embodiment) Figure 6 is a cross-sectional view of the heater element portion of the first embodiment. A Poly-Si layer 100, wiring layers 110, 120, 130, 140, a heater layer 350, a wiring layer 150 formed on the heater layer, and a cavitation-resistant layer 360 are deposited on the substrate 530 along a first direction. The vertical direction of the first direction is the same as in Figure 13. Each wiring is insulated from the others by insulating layers 200, 210, 220, 230, 240, 250. In addition, through-holes 300, 310, 320, 330, 340 are formed extending in the first direction and penetrating the insulating layers in order to electrically connect each wiring.

[0042] The connection portion 341 of the heater element 350 is connected to the wiring layer 140a via a through-hole 340a. Furthermore, it is connected to the wiring 361, which is made of the same material as the cavitation-resistant layer 360, via a through-hole 340b, heater layer 350b, and wiring layer 150a, and then to the wiring layer 150b. Next, it is connected to the VH common wiring 130a formed in the wiring layer 130 via heater layer 350c, through-hole 340c, wiring layer 140b, and through-hole 330a. Here, unlike the VH common wiring 130d described later, wiring 140b is provided separately for each heater element. The VH common wiring 130a is connected to a part of the pad 450 of the recording element substrate and is supplied with voltage from an external source.

[0043] The other connection point 342 of the heater element is connected to the wiring layer 140c via a through-hole 340d, and then to a through-hole 330b, a wiring layer 130b, a through-hole 320a, and a wiring layer 120a. Furthermore, it is connected to the wiring layer 110a via a through-hole 310a, and to one side (510a) of the switching element 510 via a through-hole 300a.

[0044] Furthermore, the other side of the switching element (510b) is connected to the common GND wiring 141 via through-hole 300b, wiring layer 110b, through-hole 310b, wiring layer 120b, through-hole 320b, wiring layer 130c, and through-hole 330c in that order. The common GND wiring 141 is formed by wiring layer 140. An ink chamber 410 is provided above the heater element, and when the switching element 510 is activated by external data, current flows to the heater element, causing it to foam as it heats up and eject ink from the ejection port 420.

[0045] Here, the heater layer 350 is preferably formed with high resistance from the viewpoint of energy saving, and a high resistance value can be obtained by increasing the resistivity of the material while keeping the film thickness thin. The heater layer can be formed, for example, with TaSiN to a thickness of about 10 nm to 50 nm.

[0046] The wiring layers 110, 120, 130, and 140 can be formed from aluminum or aluminum-containing alloys (such as AlSi or AlCu). For example, since wiring layers 130 and 140 are used to carry current to the heater, the current flowing through them is large and they are susceptible to the effects of wiring resistance. Therefore, they are formed with relatively thick films, typically 600 nm or more.

[0047] The insulating layers 200, 210, 220, 230, and 240 need to adequately cover the wiring to electrically insulate it from the wiring, and their thickness varies depending on the thickness of the underlying wiring layer. For example, if the wiring layer 130 is formed at 600 nm, the insulating layer 230 above it is generally formed at a thickness of 600 nm or more. On the other hand, if the wiring layer 130 is formed at 1000 nm, the insulating layer 230 above it is formed at a thickness of 1000 nm or more.

[0048] On the other hand, the insulating layer 250 can be made thin because it covers a thin heater. Also, from an energy-saving standpoint, it is preferable to make the film even thinner in order to efficiently transfer the heat generated by the heater element to the ink. The insulating layer 250 can be formed with a thickness of approximately 150 nm to 300 nm.

[0049] The plug is generally made of tungsten, and the barrier metal layer is formed from a material containing titanium (e.g., TiN) with a thickness of 10 nm to 30 nm.

[0050] Next, the wiring 361 can be formed from materials such as Ta, Ti, TaN, or TiN. These materials are resistant to dissolution even when a voltage is applied while in contact with ink. In this embodiment, the wiring 361 is formed from the same material as the cavitation-resistant layer 360, for example, with a thickness of 200 nm to 300 nm. For example, if it is formed using the same process as the cavitation-resistant layer 360 on the heater element, process costs can be reduced. Since the cavitation-resistant layer is originally configured to come into contact with ink, a material with high ink resistance is used from a functional standpoint. The wiring 361 is formed by making an opening in the insulating layer 250 and connecting the wiring layer 150a and the wiring layer 150b. At this time, the insulating layer 250 is formed with a thin film thickness as described above. The film thickness of the insulating layer 250 is less than the depth of the through-hole 340.

[0051] For example, even if an insulating layer opening with a width of 0.4 μm is formed in an insulating layer 250 with a film thickness of 0.2 μm, the aspect ratio can be reduced to 0.2 / 0.4 = 0.5. In practice, the width of the insulating layer opening can be made even larger, so the aspect ratio can be made even smaller. Also, for example, if a wiring 361 with a thickness of 200 nm is formed in an opening formed in an insulating layer with a thickness of 200 nm, sufficient film thickness can be ensured even at the bottom of the opening. As a result, the connection between the wiring 361 and the wiring layer 150 can be formed in a state where it is sufficiently covered with a cavitation-resistant layer with excellent ink resistance.

[0052] In this manner, a portion of the wiring that electrically connects the heater element 350 and the VH common wiring 130a is provided with wiring (cavitation-resistant wiring) 361 made of the same material as the cavitation-resistant layer 360. The cavitation-resistant wiring 361 can function as a buffer to prevent damage from disconnections in each heater section. When a heater section disconnects, the connection portion 341 of the heater element 350 may be damaged, but the buffer portion acts to prevent the effects of the heater section disconnection from affecting the VH common wiring 130a.

[0053] Figure 14 schematically shows how the plug melts due to a break in the wiring of the element substrate shown in Figure 6. As shown in Figure 14, the plug 340a melts due to the break, and the melting extends to the wiring 140a, plug 340b, and wiring layer 150a. However, the melting is stopped at the wiring layer 361. As a result, the melting does not reach the VH common wiring 130a and does not progress to the wiring of the adjacent heater.

[0054] Figure 7 is a top view showing the wiring of two heaters mounted on the element substrate shown in Figure 6, when the cavitation-resistant wiring 361 is individual wiring. Note that the cavitation-resistant layer 360 on the heater is omitted in this figure. The cavitation-resistant wiring 361 may be formed for each heater element as shown in Figure 7, and may electrically connect the common wiring 130a to each of the multiple heater elements.

[0055] Figure 8 is a top view showing the wiring of two heaters mounted on the element substrate shown in Figure 6 when the cavitation-resistant wiring 361 is a common wiring. The cavitation-resistant wiring 361 may electrically connect the common wiring 130a to at least two of the multiple heater elements, as shown in Figure 8. Even in this case, the cavitation-resistant wiring 361 can function as a buffer when the heater section is disconnected, preventing the effects of the disconnection from affecting the VH common wiring 130a.

[0056] The cavitation-resistant wiring 361 is preferably thick in order to reduce wiring resistance. However, since increasing the film thickness increases the stress on the entire element substrate, it is preferable to thicken only the cavitation-resistant wiring 361 portion. For example, the cavitation-resistant wiring 361 portion can be thickened by depositing the film twice. Alternatively, the same material as the cavitation-resistant layer may be used, but deposited using a different process. Furthermore, the cavitation-resistant wiring 361 and the cavitation-resistant layer 360 on the heater may be formed using the same process, and only the cavitation-resistant layer on the heater may be etched to make it thinner. The cavitation-resistant wiring 361 and the cavitation-resistant layer 360 may be provided on the same wiring layer, or they may be provided on separate wiring layers.

[0057] The cavitation-resistant layer may be formed from multiple layers. For example, it can be formed from multiple layers consisting of Ta in the lower layer and Ir in the upper layer. Ta functions as a film to stop the melting of the wiring, and Ir functions as a film with higher cavitation resistance in the heater section.

[0058] The cavitation-resistant wiring 361 may be covered on top by the nozzle material 400. Alternatively, an insulating layer (not shown) may be formed between the cavitation-resistant wiring 361 and the nozzle material. The insulating layer can be made of SiO, SiC, SiOC, SiON, SiOCN, etc. The insulating layer is also expected to improve the adhesion between the cavitation-resistant layer 360 and the nozzle material 400. By ensuring adhesion with the insulating layer, the material of the cavitation-resistant wiring 361 can be formed as a film with excellent dissolution resistance.

[0059] According to the embodiments described above, even when the aspect ratio of the through-hole is large, the ink resistance is excellent, and the sufficiently coated cavitation-resistant layer prevents the progression of ink dissolution, thus preventing transmission to adjacent heaters in the event of a wire break.

[0060] (Second embodiment) Figure 9 is a cross-sectional view of the heater element portion of the second embodiment. On the substrate 530, a Poly-Si layer 100, wiring layers 110, 120, 130, 140, a heater layer 350, a wiring layer 150 formed on the heater layer, and a cavitation-resistant layer 360 are deposited along a first direction. The vertical direction of the first direction is the same as in Figure 13. Each wiring is insulated from the others by insulating layers 200, 210, 220, 230, 240, 250. In addition, through-holes 300, 310, 320, 330, 340 are formed extending in the first direction and penetrating the insulating layers in order to electrically connect each wiring. The connection portion 341 of the heater element 350a is connected to the through-hole 340a and the wiring layer 140a. Furthermore, the wiring is connected to the cavitation-resistant wiring 361 via the through-hole 340b, the heater layer 350b, and the wiring layer 150a formed on the heater layer 350b, and then connected to the VH common wiring 150b formed by the wiring layer 150. At this time, since the wiring layer 150 has a lower resistance than the heater layer 350, most of the current flows through the wiring layer 150. Therefore, in the parts where the wiring layer 150 is located above the heater layer, almost no current flows through the heater layer, and thus almost no heat is generated.

[0061] At the connection portion 342 of the heater element 350, the heater element is connected to one side (510a) of the switching element via a through-hole 340d, similar to Figure 6. Then, similar to Figure 6, the other side (510b) of the switching element is electrically connected to the common GND wiring 141. An ink chamber 410 is provided above the heater element, and when the switching element 510 is turned on by external data, current flows to the heater element, causing it to heat up, foam, and eject ink from the ejection port 420.

[0062] <<Other Embodiments>> This disclosure includes configurations represented by the following examples of recording devices and control methods for recording devices. <Configuration 1> A heater layer in which multiple heaters are formed A wiring layer on which common wiring electrically connected to the plurality of heaters is formed A cavitation-resistant layer is laminated in a first direction relative to the heater layer. A recording element substrate for a liquid ejection head, including, The aforementioned common wiring includes a first common wiring for supplying voltage from an external source, The system comprises a first plug that extends from the heater layer in the direction opposite to the first direction and fills the inside of a through-hole directly connected to the heater with a conductive material to supply voltage to the heater, A recording element substrate for a liquid ejection head, characterized in that the first common wiring and the first plug are electrically connected via wiring formed of the same material as the cavitation-resistant layer. <Configuration 2> The recording element substrate for a liquid ejection head according to configuration 1, characterized in that it has an insulating layer disposed between the heater layer and the cavitation-resistant layer. <Structure 3> The recording element substrate for a liquid ejection head according to configuration 2, wherein the thickness of the insulating layer is less than the depth of the through-hole. <Structure 4> A recording element substrate for a liquid ejection head according to any one of configurations 1 to 3, characterized in that the first common wiring is located above the heater layer. <Composition 5> A recording element substrate for a liquid ejection head according to any one of configurations 1 to 4, characterized in that the wiring formed from the same material as the cavitation-resistant layer is individually electrically connected to each of the plurality of heaters. <Composition 6> A recording element substrate for a liquid ejection head according to any one of configurations 1 to 5, characterized in that the wiring formed from the same material as the cavitation-resistant layer is formed by the same process as the cavitation-resistant layer. <Composition 7> A recording element substrate for a liquid ejection head according to any one of configurations 1 to 6, characterized in that a portion of the wiring formed from the same material as the cavitation-resistant layer is formed from one of Ta, Ti, TaN, or TiN. <Structure 8> A recording element substrate for a liquid ejection head according to any one of configurations 1 to 7, characterized in that the thickness of the wiring formed from the same material as the cavitation-resistant layer is thicker than the thickness of the cavitation-resistant layer. <Composition 9> A recording element substrate for a liquid ejection head according to any one of configurations 1 to 8, characterized in that the wiring, formed from the same material as the cavitation-resistant layer, is formed from multiple layers. <Composition 10> The recording element substrate for a liquid ejection head according to configuration 9, characterized in that the wiring, formed from the same material as the cavitation-resistant layer, has a first layer in contact with the wiring on the heater wiring layer side made of one of Ta, Ti, TaN, or TiN, and a second layer in contact with the first layer on the side opposite to the wiring on the heater layer side is made of at least Ir. <Composition 11> A recording element substrate for a liquid ejection head according to any one of configurations 1 to 10, characterized in that the wiring formed from the same material as the cavitation-resistant layer has an insulating material layer further laminated in the first direction. <Composition 12> The recording element substrate for a liquid ejection head according to configuration 11, characterized in that the insulating material layer is formed of any of SiC, SiCN, SiOC, SiO, or SiCN. <Composition 13> The recording element substrate for a liquid ejection head according to configuration 11 or 12, characterized in that the insulating material layer forms a liquid ejection port. <Composition 14> The recording element substrate for a liquid ejection head according to any one of configurations 1 to 13, characterized in that the recording element substrate for the liquid ejection head includes a liquid chamber, and the wiring formed from the same material as the cavitation-resistant layer is arranged outside the liquid chamber. <Composition 15> A liquid ejection head using a recording element substrate for a liquid ejection head as described in any one of configurations 1 to 14, characterized in that it has a plurality of ejection ports for ejecting liquid. <Composition 16> A recording device that uses the liquid ejection head described in configuration 15 as an ink, with the liquid being ink, as a recording head that ejects the ink, and records on a recording medium, A recording device characterized in that the plurality of heaters are in contact with the ink, and the plurality of heaters are driven to eject ink from the ejection port. [Explanation of symbols]

[0063] 110, 120, 130, 140 wiring layers, 131 VH common wiring, 151 VH common wiring 141 Common GND wiring, 200, 210, 220, 230, 240, 250 Insulation layer, 310, 320, 330, 340 through-hole, 325, 335, 345 plug, 326, 336, 346 barrier metal layer, 350 heater, 360 cavitation-resistant layer, 361 cavitation-resistant wiring, 510 Switching element, 530 Si substrate, 700 element substrate

Claims

1. A heater layer in which multiple heaters are formed A wiring layer on which common wiring electrically connected to the plurality of heaters is formed A cavitation-resistant layer is laminated in a first direction relative to the heater layer. A recording element substrate for a liquid ejection head, including, The aforementioned common wiring includes a first common wiring for supplying voltage from an external source, The system comprises a first plug that extends from the heater layer in the direction opposite to the first direction and fills the inside of a through-hole directly connected to the heater with a conductive material to supply voltage to the heater, A recording element substrate for a liquid ejection head, characterized in that the first common wiring and the first plug are electrically connected via wiring formed of the same material as the cavitation-resistant layer.

2. The recording element substrate for a liquid ejection head according to claim 1, characterized in that it has an insulating layer disposed between the heater layer and the cavitation-resistant layer.

3. The recording element substrate for a liquid ejection head according to claim 2, wherein the thickness of the insulating layer is less than the depth of the through-hole.

4. The recording element substrate for a liquid ejection head according to claim 1, characterized in that the first common wiring is located above the heater layer.

5. The recording element substrate for a liquid ejection head according to claim 1, characterized in that the wiring formed from the same material as the cavitation-resistant layer is individually electrically connected to each of the plurality of heaters.

6. The recording element substrate for a liquid ejection head according to claim 1, characterized in that the wiring formed from the same material as the cavitation-resistant layer is formed by the same process as the cavitation-resistant layer.

7. The recording element substrate for a liquid ejection head according to claim 1, characterized in that a portion of the wiring formed from the same material as the cavitation-resistant layer is formed from one of Ta, Ti, TaN, or TiN.

8. The recording element substrate for a liquid ejection head according to claim 2, characterized in that the thickness of the wiring formed from the same material as the cavitation-resistant layer is thicker than the thickness of the cavitation-resistant layer.

9. The recording element substrate for a liquid ejection head according to claim 1, characterized in that the wiring, formed from the same material as the cavitation-resistant layer, is formed from multiple layers.

10. The recording element substrate for a liquid ejection head according to claim 9, characterized in that the wiring, formed from the same material as the cavitation-resistant layer, has a first layer in contact with the wiring on the heater layer side made of one of Ta, Ti, TaN, or TiN, and a second layer in contact with the first layer on the side opposite to the wiring on the heater layer side made of at least Ir.

11. The recording element substrate for a liquid ejection head according to claim 1, characterized in that the wiring formed from the same material as the cavitation-resistant layer has an insulating material layer further laminated in the first direction.

12. The recording element substrate for a liquid ejection head according to claim 11, characterized in that the insulating material layer is formed of any of SiC, SiCN, SiOC, SiO, or SiOCN.

13. The recording element substrate for a liquid ejection head according to claim 11, characterized in that the insulating material layer forms a liquid ejection port.

14. The recording element substrate for a liquid ejection head according to claim 1, wherein the recording element substrate for the liquid ejection head includes a liquid chamber, and the wiring formed from the same material as the cavitation-resistant layer is arranged outside the liquid chamber.

15. A liquid discharge head using a recording element substrate for a liquid discharge head according to any one of claims 1 to 14, characterized in that it has a plurality of discharge ports for discharging liquid.

16. A recording device that uses the liquid ejection head described in claim 15 as an ink, with the liquid being ink, as a recording head for ejecting the ink, and records on a recording medium, A recording device characterized in that the plurality of heaters are in contact with the ink, and the plurality of heaters are driven to eject ink from the ejection port.

Images