Liquid ejection head

Abstract

Provided are an element substrate, a liquid ejection head, and a recording device that can suppress the progression of corrosion of a wiring portion connected to a heat generating resistor element. [Solution] The recording element disclosed herein is a multilayer element substrate including a heater layer, a first wiring layer on which wiring connected to the multiple heaters having a stacked structure of three or more layers stacked sequentially along the current flow direction is formed, and a second wiring layer on which common wiring for supplying voltage from the outside to the multiple heaters is formed, wherein the multiple heaters are connected to the common wiring via the first wiring layer, the first wiring layer has a stacked structure of three or more layers, and the stacked structure has a corrosion-resistant conductive layer, a first conductive layer, and a second conductive layer.

Description

[Technical Field]

[0001] The present disclosure relates to an element substrate, a liquid ejection head, and a recording apparatus including the head, and more particularly to a recording apparatus that uses a liquid ejection head incorporating an element substrate that is suppressed from dissolving in ink as a recording head for inkjet recording. [Background technology]

[0002] Liquid ejection devices, such as inkjet recording devices, are being required to achieve ever higher image quality and faster speeds. In general, inkjet recording methods that use a thermal method involve locally heating a liquid, such as ink, through a nozzle to generate bubbles within the nozzle, which then eject the ink from the bubbles and land it on the print target. In print heads using this method, heat-generating resistor elements that heat the liquid are formed on a semiconductor substrate along with logic circuits for driving the heat-generating resistor elements. This allows the print head to meet the aforementioned demands for higher image quality and faster speeds by arranging the heat-generating resistor elements at a high density and achieving high-speed operation.

[0003] In such printheads, accidental disconnections of the heating resistor elements on the element substrate can occur. Because the area around the heating resistor elements on the element substrate is exposed to ink, disconnection of a heating resistor element can potentially lead to the ink dissolving and corrosion of the plugs and electrical wiring layers electrically connected to the heating resistor. Furthermore, if wiring corrosion starting from a certain heating resistor element progresses significantly and reaches the wiring connected to surrounding heating resistor elements, the operation of not only the heating resistor element where the corrosion originated but also the surrounding heating resistor elements can become unstable and potentially prevent normal operation. In recent years, technology has been introduced to detect disconnected heating resistor elements and replace them with other functioning heating resistor elements. However, if a group of heating resistor elements stops functioning, it becomes difficult to replace them with other functioning heater elements, leading to a deterioration in image quality.

[0004] Patent Document 1 describes a configuration in which one end of a heating resistor element is connected to a VH common wiring via a through-hole with a small aspect ratio (the ratio of the through-hole height to the through-hole diameter) that has good coverage with a barrier metal layer. With this configuration, even if the heating resistor element is broken, the progress of corrosion can be suppressed by the barrier metal layer with good coverage.

[0005] However, when elements are further miniaturized, the diameter of the through-holes becomes smaller and the aspect ratio of the through-holes becomes larger as connecting members such as plugs become smaller along with the miniaturization of wiring. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-179527 Summary of the Invention [Problem to be solved by the invention]

[0007] Normally, a barrier metal layer with high corrosion resistance to ink is formed on the sidewalls and bottom of the through-hole where the plug is formed, so the corrosion of the wiring portion described in the background art stops at the plug. However, as the aspect ratio of the through-hole increases due to the miniaturization of elements, the coverage of the barrier metal layer deteriorates. In this case, ink may penetrate the wiring portion through areas with insufficient coverage, such as around the corners of the plug bottom, and corrosion of the wiring may progress. It is desirable to take measures to suppress or prevent the progression of this corrosion.

[0008] In response to the above-described problem, an object of the present disclosure is to provide an element substrate, a liquid ejection head, and a recording apparatus that are capable of suppressing the progression of corrosion of wiring portions connected to heat-generating resistor elements. [Means for solving the problem]

[0009] The element substrate of the present disclosure for solving the above-mentioned problems is an element substrate with a multilayer structure including: a heater layer in which a plurality of heaters for discharging liquid are formed; a first wiring layer having, at least in a part thereof, a laminated structure portion of three or more layers sequentially laminated along a current-carrying direction; a first metal plug in contact with the laminated structure portion and filling a first through-hole extending toward the heater layer side; a second metal plug in contact with the laminated structure portion and filling a second through-hole extending toward the opposite side from the heater layer side; and a second wiring layer in which a common wiring for supplying a voltage from an external source to the plurality of heaters is formed; the first metal plug is in contact with the first conductive layer, and the second metal plug is in contact with the second conductive layer; the first wiring layer is electrically connected to the heater layer through the first metal plug and is electrically connected to the common wiring through the second metal plug; and the corrosion-resistant conductive layer is formed of a material that is highly resistant to corrosion by ink. [Effects of the Invention]

[0010] According to the present disclosure, even if ink penetrates into a portion of the through-hole where the coverage of the barrier metal layer is poor, the progression of wiring corrosion can be suppressed by the wiring having a corrosion-resistant conductive layer. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view showing a schematic configuration of a printing apparatus including a print head according to a typical embodiment of the present disclosure. [Figure 2] FIG. 2 is a block diagram showing a control configuration of the recording apparatus shown in FIG. [Figure 3] FIG. 2 is a diagram showing the layout configuration of an element substrate (head substrate) mounted on a printhead. [Figure 4]4 is an enlarged view of the X portion of the element substrate shown in FIG. 3. [Figure 5] FIG. 10 is a diagram showing an equivalent circuit of a drive circuit that drives one heater. [Figure 6] FIG. 10 is a cross-sectional view showing a multilayer structure of an element substrate as a comparative example. [Figure 7] 10(a) is a cross-sectional view showing the structure of a through-hole 340, FIG. 10(b) is a cross-sectional view showing the structure of a through-hole 330, and FIG. 10(c) is a cross-sectional view showing the structure of a through-hole 320. FIG. [Figure 8] 10 is a cross-sectional view showing a case where corrosion of a wiring portion of an element substrate has progressed. FIG. [Figure 9] FIG. 2 is a cross-sectional view showing a multilayer structure of an element substrate according to the first embodiment. [Figure 10] 10 is an enlarged view of a Y portion of the element substrate shown in FIG. [Figure 11] (a) is a cross-sectional view of two-layer structure A. (b) is a cross-sectional view of two-layer structure B. [Figure 12] 10 is a diagram schematically showing a state in which a plug is melted due to disconnection of a heater of the element substrate shown in FIG. 9. FIG. [Figure 13] FIG. 10 is a cross-sectional view showing a multilayer structure of an element substrate according to a second embodiment. [Figure 14] FIG. 10 is a cross-sectional view showing a multilayer structure of an element substrate according to a third embodiment. [Figure 15] 15 is an enlarged view of the XV portion of the element substrate shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Preferred embodiments of the present disclosure will be described more specifically and in detail below with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention. Furthermore, multiple features may be combined in any desired manner.

[0013] In this specification, "recording" (sometimes called "printing") refers not only to the formation of meaningful information such as characters and figures, but also to the formation of images, designs, patterns, etc. on a recording medium, or the processing of a medium, regardless of whether they are visible to humans or not.

[0014] Furthermore, "recording medium" refers not only to paper used in general recording devices, but also broadly to anything that can accept ink, such as cloth, plastic film, metal plate, glass, ceramics, wood, leather, etc.

[0015] Furthermore, "ink" (sometimes called "liquid") should be interpreted broadly, similar to the definition of "recording (printing)" above. Therefore, it refers to a liquid that can be applied to a recording medium to form an image, design, pattern, etc., or to process the recording medium, or to process the ink (for example, to solidify or insolubilize the coloring material in the ink applied to the recording medium). Therefore, a recording head can also generally be called an "ink ejection head" or a "liquid ejection head."

[0016] Furthermore, unless otherwise specified, the term "nozzle" collectively refers to the ejection opening, the liquid path communicating with it, and the element that generates the energy used to eject ink.

[0017] The element substrate (head substrate) for a printhead used below does not simply refer to a substrate made of silicon semiconductor, but refers to a configuration on which elements, wiring, etc. are provided.

[0018] Furthermore, "on the substrate" does not simply refer to the top of the element substrate, but also refers to the surface of the element substrate and the interior of the element substrate near the surface. Furthermore, "built-in" as used in this disclosure does not simply refer to the arrangement of separate elements as separate elements on the surface of a substrate, but refers to the formation and manufacture of each element integrally on an element substrate by a semiconductor circuit manufacturing process or the like.

[0019] (Outline of the recording device) FIG. 1 is a perspective view showing an outline of the configuration of a printing apparatus that performs printing using an inkjet print head (hereinafter, print head) according to a typical embodiment of the present disclosure.

[0020] As shown in Figure 1, an inkjet recording device (hereinafter referred to as recording device) 1 has a recording head 3 mounted on a carriage 2, which performs recording by ejecting ink according to the inkjet method. Recording is performed by moving the carriage 2 back and forth in the direction of arrow A. A recording medium P, such as recording paper, is fed via a paper feed mechanism 5 and transported to a recording position, where ink is ejected from the recording head 3 onto the recording medium P to perform recording.

[0021] The carriage 2 of the recording apparatus 1 not only carries the recording head 3 but also has an ink tank 6 that stores ink to be supplied to the recording head 3. The ink tank 6 is detachable from the carriage 2.

[0022] The recording device 1 shown in Figure 1 is capable of color recording, and for that purpose, four ink cartridges containing magenta (M), cyan (C), yellow (Y), and black (K) ink are mounted on the carriage 2. Each of these four ink cartridges is independent and removable.

[0023] The print head 3 of this embodiment employs an inkjet system that uses thermal energy to eject ink, and is therefore equipped with electrothermal conversion elements (heaters). These electrothermal conversion elements are provided corresponding to each ejection port, and ink is ejected from the corresponding ejection port by applying a pulse voltage to the corresponding electrothermal conversion element in response to a print signal. The printing apparatus 1 is not limited to the serial type printing apparatus described above, but can also be applied to a so-called full-line type printing apparatus in which a print head (line head) with ejection ports arranged in the width direction of the print medium is arranged in the print medium transport direction.

[0024] FIG. 2 is a block diagram showing the control configuration of the printing apparatus shown in FIG. 1. As shown in FIG. 2, the controller 600 is composed of an MPU 601, a ROM 602, an application-specific integrated circuit (ASIC) 603, a RAM 604, a system bus 605, an A / D converter 606, and other components. The ROM 602 stores programs corresponding to the control sequences described below, necessary tables, and other fixed data. The ASIC 603 generates control signals for controlling the carriage motor M1, the transport motor M2, and the printhead 3. The RAM 604 is used as an area for storing image data and as a work area for executing programs. The system bus 605 interconnects the MPU 601, the ASIC 603, and the RAM 604 to exchange data. The A / D converter 606 receives analog signals from sensors (described below), A / D converts them, and supplies the digital signals to the MPU 601.

[0025] 2, reference numeral 610 denotes a host device corresponding to a host or MFP that serves as a supply source of image data. Image data, commands, status, etc. are transmitted and received by packet communication between the host device 610 and the recording device 1 via an interface (I / F) 611.

[0026] Furthermore, reference numeral 620 denotes a group of switches, which are composed of a power switch 621, a print switch 622, a recovery switch 623, and the like.

[0027] Numeral 630 denotes a group of sensors for detecting the state of the device, and is made up of a position sensor 631, a temperature sensor 632, etc. In this embodiment, a photosensor for detecting the remaining amount of ink is also provided.

[0028] Furthermore, 640 denotes a carriage motor driver that drives a carriage motor M1 for causing the carriage 2 to scan back and forth in the direction of arrow A, and 642 denotes a transport motor driver that drives a transport motor M2 for transporting the recording medium P.

[0029] During print scanning by the print head 3, the ASIC 603 directly accesses the storage area of ​​the RAM 604 and transfers data for driving the electrothermal conversion elements to the print head. In addition, this printing device is equipped with a display unit consisting of an LCD and LED as a user interface.

[0030] Fig. 3 is a plan view showing the layout configuration of an element substrate 700 mounted on the printhead 3. The plane of the element substrate 700 shown in Fig. 3 is rectangular, and a plurality of pads 450 are provided along the long sides of the rectangular plane of the element substrate 700, and data and drive voltage are supplied from the outside (the main body of the printing apparatus) via these pads. A plurality of heaters 350, a plurality of ink supply ports 550, and a plurality of switching elements 510 are arranged in the direction of the long sides of the element substrate 700.

[0031] 3, there are provided four rows of heaters (350), four rows of ejection ports (420), eight rows of ink supply ports (550), and four rows of switching elements (510). Ink supply port rows are formed on both sides of the four rows of heaters, and magenta (M), cyan (C), yellow (Y), and black (K) inks are supplied to these four rows of ink supply ports, respectively.

[0032] Fig. 4 is an enlarged view of the X portion shown in Fig. 3. As shown in Fig. 4, ejection ports 420 that eject ink droplets are provided corresponding to each heater 350. Ink supply ports 550 that drive each heater are provided on both sides of the ejection port array.

[0033] 5 is a diagram showing an equivalent circuit of a drive circuit that drives one heater. As shown in FIG. 5, a connection portion 341 on one side of the heater (heat generating resistor) 350 is electrically connected to a VH common wiring 131 for supplying voltage. Furthermore, a connection portion 342 on the other side of the heater 350 is electrically connected to the GND common wiring 141 via a switching element 510 (driver) that switches the driving of the heater 350 on and off. In this embodiment, the switching element 510 is a MOSFET, and an external driving voltage is applied to the gate of the MOSFET to switch on and off, thereby driving the heater 350.

[0034] Next, an example of an element substrate mounted on the printhead of the printing apparatus having the above configuration will be described. First, an element substrate having a conventional configuration will be described as a comparative example.

[0035] <Comparative examples and their issues> Fig. 6 is a cross-sectional view showing the multilayer structure of an element substrate as a comparative example. Fig. 6 is a cross-sectional view taken along the line BB' shown in Fig. 4. As shown in Fig. 6, a Poly-Si layer 100, wiring layers 110, 120, 130, 140, a heater 350, and a cavitation-resistant layer 360 are formed on a Si substrate 530. The Poly-Si layer, the wiring layers, and the heater are insulated from bottom to top by insulating layers 200, 210, 220, 230, 240, and 250. In addition, through-holes 300, 310, 320, 330, and 340 are formed through the insulating layers to electrically connect the wiring.

[0036] The connection portion 341 of the heater 350 is connected to a through-hole 340a, a wire 142 formed in the wiring layer 140, a through-hole 330a, a wire 132 formed in the wiring layer 130, a through-hole 320a, and a wire 121 formed in the wiring layer 120. The wire 121 is further connected to a VH common wire 131 formed in the wiring layer 130 via a through-hole 320b. Unlike the VH common wire 131, the wire 132 is provided separately for each heater. For this reason, the wire 132 is also called an individual wire. The VH common wire 131 is electrically connected to a part of a pad 450 on the element substrate 700, and a voltage is supplied from the outside. On the other hand, the GND common wire 141 is formed in a wiring layer 140 different from the VH common wire 131.

[0037] Therefore, in order to connect the VH common wiring 131 as shown in FIG. 5 to one end of the heater 350, further connect the other end of the heater 350 to the switching element 510, and connect the switching element to the GND common wiring, each element between different layers is connected via a through hole.

[0038] In the element substrate 700, a plurality of heaters 350 are formed in the same layer, and the layer on which the plurality of heaters are formed is sometimes called a heater layer.

[0039] The other connection portion 342 of the heater 350 is connected to a through hole 340b, a wire 143 formed in the wiring layer 140, a through hole 330b, and a wire 133 formed in the wiring layer 130. Then, the heater 350 is connected to one side (510a) of the switching element via a through hole 320c, a wire 123 formed in the wiring layer 120, a through hole 310a, a wire 111 formed in the wiring layer 110, and a through hole 300a.

[0040] Furthermore, the other side (510b) of the switching element is connected to a through-hole 300b and a wiring 112 formed in the wiring layer 110. Then, it is connected to a GND common wiring 141 formed in the wiring layer 140 via a through-hole 310b, a wiring 124 formed in the wiring layer 120, a through-hole 320d, a wiring 134 formed in the wiring layer 130, and a through-hole 330c.

[0041] An ink chamber 410 is provided above the heater 350, and when a switching element 510 is turned on by data supplied from the outside, a current flows through the heater 350, and as the heater generates heat, ink bubbles and is discharged from an ejection port 420 formed in the top plate 400 of the element substrate.

[0042] The wiring layers 110, 120, 130, and 140 are formed of aluminum or an alloy containing aluminum (such as AlSi or AlCu). The wiring layers 110 and 120 are wiring layers that constitute signal wiring mainly used for data transfer. The wiring layer 130 is a wiring layer that constitutes a VH common wiring 131, and the wiring layer 140 is a wiring layer that constitutes a GND common wiring 141. Since the wiring layers 110 and 120 are used for data transfer, the current that flows through them is small and they are not easily affected by wiring resistance, so they are formed to have a relatively thin film thickness. On the other hand, since the wiring layers 130 and 140 are used to pass current through heaters, the current that flows through them is large and they are easily affected by wiring resistance, so they are formed to have a relatively thick film thickness. Therefore, the insulating layers 210 and 220 that cover the wiring layers 110 and 120 are formed to have a relatively thin film thickness, and the insulating layers 230 and 240 that cover the wiring layers 130 and 140 are formed to have a relatively thick film thickness.

[0043] FIG. 7 is a cross-sectional view showing the detailed structure of the three through holes.

[0044] The three through holes shown in FIG. 7 are the three through holes 340, 330, and 320 shown in FIG. 6, with (a) showing the structure of through hole 340, (b) showing through hole 330, and (c) showing through hole 320, respectively.

[0045] 7(a) is formed through the insulating layer 240 on the wiring layer 140. A barrier metal layer 346 is formed around a metal plug 345 that fills the inside of the through hole 340. That is, the barrier metal layer is formed on the bottom and side surfaces of the space within the through hole 340, and the metal plug 345 is formed in the space within the through hole 340 where the barrier metal layer 346 is not provided. The metal plug 345 is generally formed of tungsten, and the barrier metal layer 346 is formed of, for example, titanium (Ti) or a material containing Ti (TiN, etc.). 347 is a corner of the metal plug 345.

[0046] The through-hole 330 shown in FIG. 7(b) is formed by penetrating the insulating layer 230 on the wiring layer 130. A barrier metal layer 336 is formed around a metal plug 335 that fills the inside of the through-hole 330. That is, the barrier metal layer is formed on the bottom and side surfaces of the space within the through-hole 330, and the metal plug 335 is formed in the space within the through-hole 330 where the barrier metal layer 336 is not provided. The metal plug 335 is generally formed of tungsten, and the barrier metal layer 336 is formed of, for example, titanium (Ti) or a material containing Ti (TiN, etc.). 337 denotes a corner of the metal plug 335.

[0047] The through-hole 320 shown in FIG. 7(c) is formed by penetrating the insulating layer 220 on the wiring layer 120. A barrier metal layer 326 is formed around a metal plug 325 that fills the inside of the through-hole 320. That is, the barrier metal layer is formed on the bottom and side surfaces of the space within the through-hole 320, and the metal plug 325 is formed in the space within the through-hole 320 where the barrier metal layer 326 is not provided. The metal plug 325 is generally formed of tungsten, and the barrier metal layer 326 is formed of, for example, titanium (Ti) or a material containing Ti (TiN, etc.). 327 denotes a corner of the metal plug 325.

[0048] In the element substrate 700, accidental disconnection of the heater 350 may occur. When disconnection occurs, part of the ink-resistant cavitation-resistant layer 360 in the heater 350 is lost, and the metal plug 345 made of tungsten is exposed to ink. Even when no potential is applied to tungsten, metal dissolution by ink progresses. Furthermore, because the connection portion 341 is actually electrically connected to the VH common wiring 131 (high potential), there is a risk that dissolution of the metal plug 345 will progress further.

[0049] Here, the barrier metal layer is less soluble in ink than tungsten, so the progress of dissolution should be suppressed by the barrier metal layer. However, as the aspect ratio of the through-hole increases, the film-forming material that makes up the barrier metal layer has difficulty reaching the corners of the through-hole (corner 347 in Figure 7(a)). As a result, the thickness of the barrier metal layer tends to be thin at the corners of the through-hole, and in some cases, the thickness of the barrier metal layer is insufficient, causing dissolution by the ink. A similar situation can occur in through-hole 330.

[0050] Fig. 8 is a cross-sectional view taken along the line BB' shown in Fig. 4 when corrosion of the wiring layer of the element substrate has progressed. In Fig. 8, the same components as those already explained with reference to Fig. 6 are given the same reference numerals, and their explanation will be omitted.

[0051] As shown by the arrows in Figure 8, dissolution progresses from the corner of through-hole 340 (corner 347 in Figure 7(a)) through the barrier metal layer (barrier metal layer 346 in Figure 7(a)). The ink that has penetrated the barrier metal layer dissolves wiring 142, and dissolution similarly progresses in through-hole 330.

[0052] Comparing through hole 320 and through hole 330, through hole 330 has a large aspect ratio, and the thickness of barrier metal layer 336 tends to be thin at corners 337, resulting in relatively poor coverage. Note that through hole 340, like through hole 330, also has a larger aspect ratio than through hole 320, and the coverage of barrier metal layer 346 is relatively poor. On the other hand, through hole 320 has a small aspect ratio, and the coverage of barrier metal layer 326 is good even at corners 327. Therefore, in through hole 320, ink is less likely to penetrate into wiring layer 120 from corners 327, thereby suppressing the progress of dissolution.

[0053] However, as elements become smaller, the diameter of through-holes becomes smaller and the aspect ratio of through-holes increases due to the miniaturization of wiring and connecting members such as plugs. This means that the coverage of the barrier metal layer at the corners of the through-holes becomes poor, and ink may penetrate through the areas with insufficient coverage, causing the dissolution of the wiring.

[0054] <Structure of element substrate according to first embodiment> Fig. 9 is a cross-sectional view showing the multi-layer structure of the element substrate according to the first embodiment. In Fig. 9, the same components as those already explained with reference to Fig. 6 and Fig. 8 are given the same reference numerals, and their explanation will be omitted.

[0055] As shown in FIG. 9, the connection portion 341 of the heater 350 is connected to the through-hole 340a, the laminated structure portion 144 formed separately from the wiring layer 140, the through-hole 330a, and the wiring 132 formed in the wiring layer .

[0056] Fig. 10 is an enlarged view of the X portion of the element substrate shown in Fig. 9. In Fig. 10, the same components as those already explained with reference to Figs. 6, 7, 8, and 9 are given the same reference numerals, and their explanation will be omitted.

[0057] As shown in FIG. 10, the laminated structure 144 has a laminated structure of, from the top, a conductive layer 144a, a corrosion-resistant conductive layer 144b, and a conductive layer 144c. The conductive layers 144a and 144c are formed of aluminum or an aluminum alloy (such as AlSi or AlCu). Examples of conductive materials that can be used for the corrosion-resistant conductive layer 144b include metal nitrides such as titanium nitride (TiN) and tantalum nitride (TaN), which are commonly used as barrier metals in semiconductor manufacturing processes. Therefore, they are particularly suitable for application as conductive films that are easy to incorporate into the manufacturing process of the device substrate and have high corrosion resistance. Other examples include nitride films made of zirconium nitride, niobium nitride, vanadium nitride, tungsten nitride, or alloys such as TaSiN, TiSiN, and WSiN. Metals that are resistant to ink dissolution even when a voltage is applied, such as titanium and tantalum, can also be used.

[0058] 10, the corrosion-resistant conductive layer 144b is formed on a flat surface on the conductive layer 144c, providing better coverage than a barrier metal layer formed in a through-hole. The thickness of the corrosion-resistant conductive layer 144b is preferably 20 nm or more to prevent the wiring from being dissolved by ink. On the other hand, a thickness of 70 nm or less is preferable to prevent an increase in wiring resistance.

[0059] According to the configuration of the embodiment described above, the connection portion 341 of the heater 350 is electrically connected to the VH common wiring 131 via the laminated structure 144 including the corrosion-resistant conductive layer 144b. In this embodiment, the laminated structure including the corrosion-resistant conductive layer is formed in the wiring layer 140, but it may be formed in any wiring layer between the heater and the VH common wiring. Providing the laminated structure in a wiring layer close to the heater can suppress the progress of dissolution at an early stage.

[0060] 10 shows a three-layer wiring configuration in which corrosion-resistant conductive layer 144b is placed between conductive layer 144a and conductive layer 144c. However, it is believed that the progression of wiring dissolution can also be suppressed by using a two-layer wiring configuration consisting of a corrosion-resistant conductive layer and a conductive layer. Possible two-layer configurations include a configuration in which a corrosion-resistant conductive layer is placed on the top layer and a conductive layer is placed on the bottom layer (hereinafter referred to as two-layer configuration A), and a configuration in which a conductive layer is placed on the top layer and a corrosion-resistant conductive layer is placed on the bottom layer (hereinafter referred to as two-layer configuration B).

[0061] Figure 11 shows cross-sectional views of two-layer structure A and two-layer structure B. In Figure 11, the same components as those already explained with reference to Figures 6, 7, 8, 9, and 10 are given the same reference numerals, and their explanation will be omitted.

[0062] First, in the two-layer structure A shown in FIG. 11(a), the corrosion-resistant conductive layer is also etched when forming the through-holes (part G in FIG. 11(a)). As a result, the coverage of the corrosion-resistant conductive layer is reduced, and there is a possibility that sufficient effectiveness in suppressing wiring dissolution cannot be achieved. By increasing the thickness of the corrosion-resistant conductive layer, it is possible to ensure coverage even if etching occurs when forming the through-holes, but there is also a concern that the increase in thickness of the corrosion-resistant conductive layer will increase the wiring resistance. On the other hand, in the three-layer structure shown in FIG. 9, there is no risk of the coverage of the corrosion-resistant conductive layer 144b being reduced by etching.

[0063] In addition, in the two-layer structure B shown in FIG. 11(b), through-holes are located below the corrosion-resistant conductive layer. Seams may occur when forming the metal filling the through-holes (part H in FIG. 11(b)). The seams may reduce the flatness of the surface on which the corrosion-resistant conductive layer is formed, potentially reducing the coverage of the corrosion-resistant conductive layer. As with the two-layer structure A, coverage can be ensured by increasing the thickness of the corrosion-resistant conductive layer, but there is also a concern that increasing the thickness of the corrosion-resistant conductive layer may increase the wiring resistance. On the other hand, in the three-layer structure shown in FIG. 9, the corrosion-resistant conductive layer 144b is formed on a relatively flat conductive layer 144c, so there is no impact from seams.

[0064] FIG. 12 is a diagram showing a state in which the plug melts due to disconnection of the heater of the element substrate shown in FIG.

[0065] As shown by the arrow in Figure 12, even if the heater breaks and ink penetrates the corner 347 of the through-hole 340a shown in Figure 10, causing dissolution to reach the laminated structure 144, the corrosion-resistant conductive layer 144b, which has good coating properties, can suppress the progress of dissolution.

[0066] <Structure of element substrate according to second embodiment> Figure 13 is a cross-sectional view showing the multi-layer structure of an element substrate according to the second embodiment. In Figure 13, the same components as those already explained with reference to Figures 6, 8, 9, and 10 are given the same reference numerals, and their explanation will be omitted. Here, the characteristic configuration of the second embodiment will be explained.

[0067] In this second embodiment, a multilayer structure 150 is formed with the same structure as the multilayer structure 144 shown in Fig. 10. That is, a multilayer structure 150 including conductive layers 150a-c is formed in the same layer structure as the conductive layer 144a, corrosion-resistant conductive layer 144b, and conductive layer 144c shown in Fig. 10. Note that the Z portion shown in Fig. 13 has exactly the same structure as in Fig. 10 except for the reference numerals, and therefore is not shown in the figure.

[0068] In the first embodiment, the wirings 141 and 143 and the laminated structure 144 are formed separately, whereas in the second embodiment, the laminated structure 150 is formed all at once, thereby reducing the number of manufacturing steps compared to Example 1.

[0069] In the above configuration, similarly to the first embodiment, even if the heater breaks and ink penetrates the corner 347 of the through-hole 340a shown in Fig. 13, causing dissolution to reach the multilayer structure 150, the corrosion-resistant conductive layer 150b with good coverage can suppress the progress of dissolution. Furthermore, even if a break occurs between the heater layer and the switching element, and between the switching element and the GND common wiring, causing dissolution to progress, the corrosion-resistant conductive layer 150b of the multilayer structure 150 can suppress the progress of dissolution.

[0070] <Structure of element substrate according to the third embodiment> Figure 14 is a cross-sectional view showing the multi-layer structure of an element substrate according to the third embodiment. In Figure 14, the same components as those already explained with reference to Figures 6, 8, 9, 10, and 13 are given the same reference numerals, and their explanation will be omitted. Here, the characteristic configuration of the third embodiment will be explained.

[0071] In the third embodiment, a laminated structure 152 is formed separately from the wiring layer 140 .

[0072] Fig. 15 is an enlarged view of the XV portion of the element substrate shown in Fig. 14. In Fig. 15, the same components as those already explained with reference to Figs. 6, 7, 8, 9, 10, and 13 are designated by the same reference numerals, and explanations thereof will be omitted.

[0073] In the third embodiment, as shown in FIG. 15 , the laminated structure 152 has a laminated structure of a conductive layer 152a, a corrosion-resistant conductive layer 152b, and a conductive layer 152c, with the corrosion-resistant conductive layer 152b also formed on the side of the conductive layer 152c. The conductive layers 152a and 152c are formed of aluminum or an aluminum alloy (e.g., AlSi or AlCu). Examples of conductive materials that can be used for the corrosion-resistant conductive layer 152b include metal nitrides such as titanium nitride (TiN) and tantalum nitride (TaN), which are commonly used as barrier metals in semiconductor manufacturing processes. Therefore, these materials are particularly suitable for application as conductive films that are easily incorporated into the device substrate manufacturing process and have high corrosion resistance. Other examples include nitride films made of zirconium nitride, niobium nitride, vanadium nitride, tungsten nitride, or alloys such as TaSiN, TiSiN, and WSiN. Metals that are resistant to ink dissolution even when a voltage is applied, such as titanium and tantalum, can also be used.

[0074] In the stacked structure shown in FIG. 15 , the corrosion-resistant conductive layer 152b is formed on a flat surface on the conductive layer 152c, providing better coverage than a barrier metal layer formed in a through-hole. Furthermore, in this embodiment, unlike the element substrates of the first and second embodiments, the corrosion-resistant conductive layer covers the side surfaces of the conductive layer below the corrosion-resistant conductive layer. This prevents the corrosion-resistant conductive layer from wrapping around the side surfaces and causing dissolution. Therefore, the element substrate is more resistant to dissolution than the element substrates of the first and second embodiments. In the embodiment shown in FIG. 15 , the corrosion-resistant conductive layer is also formed on the side surfaces of the conductive layer 152c. However, the corrosion-resistant conductive layer may be formed on the side surfaces of the conductive layer 152a, or on either the side surfaces of the conductive layer 152a or the conductive layer 152c.

[0075] In the above-described embodiment, an element substrate used in a print head that ejects ink in a printing apparatus has been described as an example, but the present disclosure is not limited thereto. The present disclosure is applicable to devices such as printers, copiers, facsimiles with communication systems, word processors with printer units, and industrial printing devices combined with various processing devices. The element substrate of the present disclosure can also be used in printing devices used for applications such as biochip production, electronic circuit printing, and color filter manufacturing.

[0076] The present disclosure is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention.

[0077] <<Other embodiments>> The present disclosure includes configurations typified by the following examples of a recording apparatus and a control method for a recording apparatus. <Configuration 1> a heater layer in which a plurality of heaters for ejecting liquid are formed; At least a part of the laminated structure has three or more layers stacked in sequence along the current-carrying direction. a first wiring layer; a first metal plug that contacts the laminated structure and fills the inside of a first through hole that extends toward the heater layer; a second metal plug that contacts the laminated structure and fills the inside of a second through hole that extends toward the opposite side from the heater layer; a second wiring layer in which a common wiring for supplying a voltage to the plurality of heaters from an external source is formed, the plurality of heaters are connected to the common wiring via the first wiring layer; the laminated structure includes a corrosion-resistant conductive layer, a first conductive layer, and a second conductive layer; a surface of the corrosion-resistant conductive layer on the heater layer side contacts the first conductive layer; a surface of the corrosion-resistant conductive layer opposite to the heater layer contacts the second conductive layer; the first metal plug contacts the first conductive layer; the second metal plug contacts the second conductive layer; the first wiring layer is electrically connected to the heater layer through the first metal plug and is electrically connected to the common wiring through the second metal plug; The element substrate, wherein the corrosion-resistant conductive layer is formed from a material that is highly resistant to corrosion by ink. <Configuration 2> The element substrate according to configuration 1, wherein the corrosion-resistant conductive layer is also formed on a surface facing in a direction different from the stacking direction of the first conductive layer and / or the second conductive layer. <Configuration 3> 3. The element substrate according to claim 1, wherein the first conductive layer and the second conductive layer contain aluminum. <Configuration 4> 4. The element substrate according to any one of configurations 1 to 3, wherein the corrosion-resistant conductive layer is made of any one of TiN, TiW, TaN, TaSiN, TiSiN, WSiN, Ti, and Ta. <Configuration 5> 5. The element substrate according to any one of configurations 1 to 4, comprising the corrosion-resistant conductive layer having a thickness of 20 nm or more in the lamination direction. <Configuration 6> 6. The element substrate according to any one of configurations 1 to 5, comprising the corrosion-resistant conductive layer having a thickness of 70 nm or less in the lamination direction. <Configuration 7> 7. The element substrate according to any one of configurations 1 to 6, further comprising a switching element electrically connected to the heater layer, and further including the laminated structure between the heater layer and the switching element. <Configuration 8> The element substrate according to any one of structures 1 to 7, further comprising a third wiring layer having a GND common wiring electrically connected to the heater layer, and further including the laminated structure portion between the heater layer and the GND common wiring. [Explanation of symbols]

[0078] 110, 120, 130, 140 wiring layers 144, 150, 152 Laminated structure section 131 VH common wiring 141 GND common wiring 200, 210, 220, 230, 240, 250 Insulation layer 310, 320, 330, 340 through hole 325, 335, 345 plugs 326, 336, 346 Barrier metal layer 350 heater 360 Cavitation-resistant layer 510 Switching element 530 Si substrate 700 element substrate

Claims

1. a heater layer in which a plurality of heaters for ejecting liquid are formed; At least a part of the laminated structure has three or more layers stacked in sequence along the current-carrying direction. a first wiring layer; a first metal plug that contacts the laminated structure and fills the inside of a first through hole that extends toward the heater layer; a second metal plug that contacts the laminated structure and fills the inside of a second through hole that extends toward the opposite side from the heater layer; a second wiring layer in which a common wiring for supplying a voltage from an external source to the plurality of heaters is formed, the plurality of heaters are connected to the common wiring via the first wiring layer; the laminated structure includes a corrosion-resistant conductive layer, a first conductive layer, and a second conductive layer; a surface of the corrosion-resistant conductive layer on the heater layer side contacts the first conductive layer; a surface of the corrosion-resistant conductive layer opposite to the heater layer side contacts the second conductive layer; the first metal plug contacts the first conductive layer; the second metal plug contacts the second conductive layer; the first wiring layer is electrically connected to the heater layer through the first metal plug and is electrically connected to the common wiring through the second metal plug; The element substrate, wherein the corrosion-resistant conductive layer is formed from a material that is highly resistant to corrosion by ink.

2. 2. The element substrate according to claim 1, wherein the corrosion-resistant conductive layer is also formed on a surface facing in a direction different from the stacking direction of the first conductive layer and / or the second conductive layer.

3. 2. The element substrate according to claim 1, wherein the first conductive layer and the second conductive layer contain aluminum.

4. 2. The element substrate according to claim 1, wherein the corrosion-resistant conductive layer is made of any one of TiN, TiW, TaN, TaSiN, TiSiN, WSiN, Ti, and Ta.

5. 2. The element substrate according to claim 1, wherein the corrosion-resistant conductive layer has a thickness of 20 nm or more in the lamination direction.

6. 2. The element substrate according to claim 1, wherein the corrosion-resistant conductive layer has a thickness of 70 nm or less in the lamination direction.

7. The element substrate according to claim 1 , further comprising a switching element electrically connected to the heater layer, and further including the laminated structure between the heater layer and the switching element.

8. 2. The element substrate according to claim 1, further comprising a third wiring layer having a GND common wiring electrically connected to said heater layer, and further comprising said laminated structure portion between said heater layer and said GND common wiring.

Images