Liquid discharge head

Abstract

To provide a liquid discharge head capable of suppressing a failure caused by bubbles inside a joint layer.SOLUTION: The liquid discharge head comprises: a first flow path substrate 1 having a first surface 1a and a second surface 1b; a second flow path substrate 2 having a third surface 2a and a fourth surface 2b, and including an energy generation element 18 provided in the fourth surface 2b, and a connection terminal 13 provided in the fourth surface 2b; an element substrate 100 including a joint layer 17 that connects the second and third surfaces 1b and 2a; a wiring substrate having an external terminal electrically connected to the connection terminal 13; an electric connection part 22 for electrically connecting the connection terminal 13 and the external terminal; and a sealing resin 23 fixed so as to cover ends of the electric connection part 22 and the fourth surface 2b of the joint layer 17. A step 20 protruding from at least one of the second surface 1b and the third surface 2a is provided between the second surface 1b and the third surface 2a, the step 20 being disposed at a position overlapping the connection terminal 13 when seen in a first direction D1.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head. [Background technology]

[0002] Liquid ejection devices such as inkjet printers are provided with a liquid ejection head that ejects liquid such as ink from a plurality of ejection ports. A conventionally known liquid ejection head includes a flow path forming substrate that forms the ejection ports and the flow paths through which the ejected liquid passes. The flow path forming substrate is formed by bonding multiple substrates together, and since the bonding condition affects the function of the liquid ejection head, various proposals have been made for controlling the bonding condition.

[0003] Patent document 1 discloses a liquid ejection head that includes a first substrate provided with a vibration plate, a first step portion, and a second step portion for the purpose of preventing the adhesive that bonds the substrates from flowing out, and a second substrate that is bonded to the first substrate with adhesive. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6303285 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, in a configuration in which multiple substrates are bonded together with an adhesive, air bubbles may be generated inside the bonding layer that bonds the substrates together during the manufacturing of the flow path forming substrate. Such air bubbles may cause problems, such as reducing the bonding strength in wire bonding.

[0006] The present invention has been made in light of the above technical background, and has an object to provide a liquid ejection head that can suppress defects caused by air bubbles inside the bonding layer. [Means for solving the problem]

[0007] In order to achieve the above object, the liquid ejection head of the present invention comprises: a first flow path substrate having a first surface on which a discharge port for discharging a liquid is formed and a second surface opposite to the first surface; a second flow path substrate having a third surface joined to the second surface of the first flow path substrate and a fourth surface opposite to the third surface, the second flow path substrate including a flow path for supplying the liquid to be ejected from the ejection port to the first flow path substrate, an energy generating element that generates energy for ejecting the liquid, and a connection terminal provided on the fourth surface for supplying electricity to the energy generating element; a bonding layer between the second surface and the third surface, the bonding layer bonding the second surface and the third surface; an element substrate comprising: a wiring board having external terminals electrically connected to the connection terminals; an electrical connection portion that electrically connects the connection terminal and the external terminal; a sealing resin fixed so as to cover the electrical connection portion and an end portion of the fourth surface of the bonding layer; Equipped with Between the second surface and the third surface, there is provided a step that protrudes from at least one of the second surface and the third surface and is positioned so as to overlap with the connection terminal when viewed in a first direction perpendicular to the fourth surface. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a liquid ejection head that can suppress defects caused by air bubbles inside the bonding layer. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is an exploded perspective view of the element substrate according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the element substrate according to the first embodiment. [Figure 3] FIG. 10 is a cross-sectional view of an element substrate according to a comparative example. [Figure 4] FIG. 10 is a diagram showing how air bubbles are released into the sealing resin in the comparative example. [Figure 5] 5A to 5C are explanatory diagrams illustrating an example of a method for manufacturing the liquid ejection head according to the first embodiment. [Figure 6] FIG. 4 is a cross-sectional view showing a state in which bubbles are generated in the bonding layer according to the first embodiment. [Figure 7] FIG. 2 is a transparent plan view of the element substrate according to the first embodiment. [Figure 8] FIG. 10 is a cross-sectional view of an element substrate according to a second embodiment. [Figure 9] FIG. 10 is a cross-sectional view showing the details of a step portion according to the second embodiment. [Figure 10] FIG. 10 is an explanatory diagram illustrating how bubbles are released into the sealing resin. [Figure 11] FIG. 10 is a transparent plan view showing a PAD and a step according to another embodiment. [Figure 12] FIG. 1 is a perspective view of a liquid ejection head according to a first embodiment. [Figure 13] FIG. 2 is a perspective view showing a detailed configuration of the liquid ejection unit according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes in detail exemplary embodiments of the present invention with reference to the drawings. The dimensions, materials, shapes, and relative positions of the components described in the embodiments may be changed as appropriate depending on the configuration and various conditions of the device to which the invention is applied. In other words, the scope of the present invention is not limited to the following embodiments.

[0011] The present invention is particularly suitable for a liquid ejection device that ejects ink as a recording liquid onto a recording medium such as paper to record an image, and for a liquid ejection head provided in the liquid ejection device. Below, an embodiment in which the present invention is applied to an inkjet head that ejects ink onto a recording medium by driving an actuator provided on an element substrate to record an image on the recording medium will be described. However, the present invention can also be applied to inkjet heads that eject liquids other than ink, and other liquid ejection heads and other devices.

[0012] First Embodiment FIG. 12 is a perspective view showing a liquid ejection head 50 according to this embodiment.

[0013] As shown in FIG. 12, the head portion of the liquid ejection head 50 includes a liquid ejection unit 502 having a mechanism for ejecting liquid, and a common support member 503 that supports a plurality of liquid ejection units 502 .

[0014] In this embodiment, four liquid ejection units 502 are arranged in a staggered pattern on a common support member 503. Each liquid ejection unit 502 has approximately 1000 ejection ports 16 formed therein, and the liquid ejection unit 502 ejects liquid from the ejection ports 16, enabling recording at 1200 dpi.

[0015] Fig. 13 is a perspective view showing a detailed configuration of the liquid ejection unit 502 shown in Fig. 12. As shown in Fig. 13, the liquid ejection unit 502 includes an element substrate 100 including ejection ports 16 for ejecting liquid, liquid flow paths communicating with the ejection ports, energy generating elements, etc., and a and a wiring board 70 electrically connected to the wiring board 70. Examples of the wiring board 70 include FPC (Flexible Printed Circuits) and TAB (Tape Backing Board). Automated Bonding, etc.

[0016] The liquid ejection unit 202 includes a support member 505 for reinforcing the element substrate 100. The support member 505 is bonded to the ejection surface side of the element substrate 100. The wiring substrate 70 is provided with a drive circuit board 504 for driving an energy generating element (not shown) that generates energy for ejecting the liquid. In this embodiment, a piezoelectric element is used as the energy generating element.

[0017] The wiring board 70 is a flexible wiring board that is connected to the element substrate 100 and the liquid ejection device and transmits power from the liquid ejection device to the element substrate 100. The wiring board 70 is provided with contacts that are electrically connected to the liquid ejection device and external terminals that are electrically connected to the element substrate 100.

[0018] The inkjet head may be configured as a separate unit from the ink tank, as described above, and ink may be supplied via a tube or the like. Alternatively, the inkjet head may be integrated with the ink tank. For example, the ink tank may be detachably attached, so that when the ink in the ink tank runs out, it can be removed and a new ink tank can be installed. Furthermore, the inkjet head may be applied to a serial recording system as described above, or may be applied to a line printer, having nozzles across the entire width of the recording medium.

[0019] (Element substrate 100) The configuration of the element substrate 100 will be described. FIG. 1 is an exploded perspective view of the element substrate 100. As shown in FIG. 1, the element substrate 100 is configured by stacking three substrates: a first flow path substrate 1, a second flow path substrate 2, and a third flow path substrate 3. Note that the basic configuration of the element substrate 100 described below is merely an example, and the configuration of a liquid ejection head to which the present invention can be applied is not limited to this. Furthermore, in each figure, the components of the element substrate 100 are shown in a simplified manner, and only representative components are shown, with some components being omitted.

[0020] Hereinafter, the stacking direction of the first flow path substrate 1, the second flow path substrate 2, and the third flow path substrate 3, which is perpendicular to the bonding surfaces of the substrates, will be referred to as the first direction D1. The direction along one side of the first flow path substrate 1 will be referred to as the second direction D2, and the direction that intersects with the second direction D2 and follows another side of the first flow path substrate 1 will be referred to as the third direction D3. In the first embodiment, the first direction D1, the second direction D2, and the third direction D3 are perpendicular to one another. The first direction D1 is a direction that is approximately parallel to the liquid ejection direction of the liquid ejection head 50.

[0021] The first flow path substrate 1, the second flow path substrate 2, and the third flow path substrate 3 are each a plate-shaped flow path forming member in which a flow path through which ink passes is formed. In the first embodiment, the element substrate 100 is configured by stacking the first flow path substrate 1, the second flow path substrate 2, and the third flow path substrate 3 in this order.

[0022] The first flow path substrate 1 has a first surface 1a on which ejection ports 16 through which ink is ejected are formed, and a second surface 1b on which flow paths 15 communicating with the ejection ports 16 are opened. The first surface 1a and the second surface 1b are surfaces facing in opposite directions and perpendicular to the first direction D1. The second surface 1b is a bonding surface that is bonded to the second flow path substrate 2.

[0023] The first flow path substrate 1 is provided with ejection port rows, each of which has a plurality of ejection ports 16 aligned in the second direction D2, at one end and the other end in the third direction D3. A flow path 15 is formed corresponding to each of the ejection ports 16.

[0024] The second surface 1b of the first flow path substrate 1 is provided with a step portion 21 constituted by a plurality of steps 20 protruding from the second surface 1b toward the second flow path substrate 2. In the first embodiment, a plurality of step rows are provided, each of which has a plurality of steps 20 arranged side by side in the second direction D2. FIG. 1 shows a state in which step portions 21 constituted by three step rows are provided at each of one end and the other end of the first flow path substrate 1 in the third direction, but the configuration of the step portions 21 is not limited to that shown. The steps 20 are arranged at positions that overlap with PADs 13 provided on the second flow path substrate 2 when viewed in the first direction D1.

[0025] The second flow path substrate 2 has a third surface 2a bonded to the second surface 1b of the first flow path substrate 1, and a fourth surface 2b on which a plurality of energy generating elements 18 and a plurality of PADs 13 are provided. The third surface 2a and the fourth surface 2b face in opposite directions and are perpendicular to the first direction D1. The fourth surface 2b is a bonding surface bonded to the third flow path substrate 3. The PADs 13 are connection terminals (electrode pads) for supplying electricity to the energy generating elements 18. The second flow path substrate 2 also has a plurality of pressure chambers 14 formed on the third surface 2a. The pressure chambers 14 function as flow paths for ink flowing from the third flow path substrate 3 to the first flow path substrate 1.

[0026] The third flow path substrate 3 has a fifth surface 3a joined to the third surface 2a of the second flow path substrate 2, and a sixth surface 3b on which a plurality of inlets 11 for ink to flow in are formed. The fifth surface 3a and the sixth surface 3b face in opposite directions and are perpendicular to the first direction D1. A flow path formed inside the third flow path substrate 3 and having the inlet 11 at one end opens to the fifth surface 3a. The third flow path substrate 3 also has a plurality of housing portions 12 formed therein, each having an energy generating element 18 disposed therein. The energy generating element 18 generates energy for ejecting ink from the ejection port 16.

[0027] In the element substrate 100, ink flows in through an inlet 11 in the third flow path substrate 3, passes through a pressure chamber 14 in the second flow path substrate 2 and a flow path 15 in the first flow path substrate 1, and is ejected from an ejection port 16. That is, inside the element substrate 100, a continuous through-hole with one end serving as the inlet 11 and the other end serving as the ejection port 16 is formed as a flow path. The flow path may be formed so as to connect one inlet 11 to one ejection port 16, or may be formed so as to connect one inlet 11 to multiple ejection ports 16.

[0028] 2 is a cross-sectional view of the element substrate 100 when viewed in the second direction D2, and shows the internal configuration of the element substrate 100. The second surface 1b of the first flow path substrate 1 and the third surface 2a of the second flow path substrate 2 are joined to each other, for example, by an adhesive, to form a joining layer (joint portion) 17. Furthermore, the fourth surface 2b of the second flow path substrate 2 and the fifth surface 3a of the third flow path substrate 3 are joined to each other, for example, by an adhesive, to form a joining layer (joint portion) 19.

[0029] For example, a piezoelectric element can be used as the energy generating element 18 provided inside the housing 12. A vibration plate can be provided to cover the opening on the fifth surface 3a of the housing 12, and a piezoelectric element can be provided on the vibration plate, so that the piezoelectric element functions as the energy generating element 18 that generates energy to eject ink from the ejection ports 16. Alternatively, for example, a heating element such as a heater that generates thermal energy for ejecting ink can be used as the energy generating element 18. The energy generating element 18 is electrically connected to the PAD 13 by wiring.

[0030] The PAD 13 provided on the fourth surface 2b of the second flow path substrate 2 is provided with an element substrate 100 and a wiring substrate. One end of the wire 22, which is a connecting member for electrically connecting the plates 70, is connected to the pad 13. The other end of the wire 22 is connected to an external terminal provided on the wiring substrate 70. In the first embodiment, the external terminal is located on the third direction D3 side with respect to the element substrate 100. Therefore, the wire 22 is arranged from on the pad 13 to on the wiring substrate 70 so as to straddle the side 2b1 extending in the second direction D2 of the fourth surface 2b of the second flow path substrate 2 in the third direction D3. Note that the end of the second flow path substrate 2 opposite to the end in the third direction D3 shown in FIG. 2 is similarly configured.

[0031] To protect the wires 22 serving as electrical connections electrically connecting the PAD 13 to the external terminals, the wires 22 are covered with a sealing resin 23. The sealing resin 23 is further provided to cover the connection portions between the PAD 13 and the wires 22, the end faces of the element substrate 100 in the third direction D3, and the connection portions between the external terminals of the wiring substrate 70 and the wires 22. The sealing resin 23 is provided to cover at least the end faces of the second flow path substrate 2 on the side of side 2b1 across which the wires 22 straddle, and the end portions of the bonding layer 17 on the side closer to side 2b1. Note that the electrical connection portions to which the present invention is applicable are not limited to wires; for example, the electrical connection portions electrically connecting the PAD 13 to the external terminals may be inner leads of the wiring substrate 70.

[0032] Each of the components of the first flow path substrate 1, the second flow path substrate 2, and the third flow path substrate 3 is formed by processing a single crystal substrate of silicon (Si) using semiconductor manufacturing techniques such as etching.

[0033] (Comparative Example) In the first embodiment, the step portion 21 is provided on the second surface 1b of the first flow path substrate 1. The step portion 21 is provided to suppress defects caused by air bubbles when the air bubbles are generated inside the bonding layer 17. Therefore, first, using a comparative example in which the step portion 21 is not provided, defects that may be caused by the air bubbles generated in the bonding layer 17 will be described.

[0034] 3 is a cross-sectional view of the element substrate 200 according to the comparative example when viewed in the second direction D2, and shows the internal configuration of the element substrate 200. The element substrate 200 differs from the element substrate 100 of the first embodiment in that it does not have a step portion 21. Hereinafter, in the configuration of the comparative example, the same components as those of the first embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0035] In the comparative example, the second surface 1b of the first flow path substrate 1 and the third surface 2a of the second flow path substrate 2 are both flat, and the first flow path substrate 1 and the second flow path substrate 2 are bonded together at their flat surfaces. When the first flow path substrate 1 and the second flow path substrate 2 are bonded together, air bubbles may be generated inside the bonding layer 17. Fig. 3 shows an example in which air bubbles 30 are generated at the end of the bonding layer 17 in the third direction D3 when the wire 22 is connected to the element substrate 200 and is not yet covered with the sealing resin 23.

[0036] 3, when sealing resin 23 is applied (filled) so as to cover the ends of wires 22 and bonding layer 17, air bubbles in bonding layer 17 may be released into sealing resin 23. Fig. 4 shows a state in which air bubbles 30 are released into sealing resin 23 in element substrate 200 according to the comparative example.

[0037] In the comparative example, bubbles 30 larger than the size of the wire mounting area are generated directly below the PAD 13 in the bonding layer 17, which may impair ultrasonic conduction during pressure bonding of the wires 22, resulting in a risk of reduced bonding strength. Furthermore, when the bubbles 30 are released into the sealing resin 23, the bubbles 30 may come into contact with the wires 22, reducing bonding strength, or may form spaces between adjacent wires 22, impairing electrical insulation and causing short circuits. In this way, bubbles in the bonding layer 17 cause various problems, such as manufacturing defects and breakdowns of the element substrate, and are a major cause of problems. It can have an impact.

[0038] (Method of manufacturing a liquid ejection head) In order to prevent defects caused by bubbles generated in the bonding layer 17, in the first embodiment, a step portion 21 is provided between the second surface 1b and the third surface 2a. Here, a method for manufacturing the liquid ejection head 50 including the step portion 21 will be described. Figures 5(a) to 5(i) are explanatory diagrams of an example of a method for manufacturing the liquid ejection head 50 according to the first embodiment, and mainly show the manufacturing process of the element substrate 100 and the process of connecting the element substrate 100 and the wiring substrate 70.

[0039] 5(a) shows a third flow path substrate 3 on which a flow path including an inlet 11 and a housing part 12 are formed. The inlet 11 is formed on the sixth surface 3b, and the flow path is formed so as to penetrate from the sixth surface 3b to the fifth surface 3a of the third flow path substrate 3. The housing part 12 is formed on the fifth surface 3a side.

[0040] 5(b) shows a state in which the adhesive has been transferred to the fifth surface 3a of the third flow path substrate 3. An adhesive 190 for bonding to the second flow path substrate 2 is applied all over the fifth surface 3a.

[0041] 5(c) shows a state in which the second flow path substrate 2 and the third flow path substrate 3 are bonded together. The fourth surface 2b of the second flow path substrate 2 and the fifth surface 3a of the third flow path substrate 3 are bonded together via an adhesive 190, and a bonding layer 19 is formed between the second flow path substrate 2 and the third flow path substrate 3. At this time, both substrates are bonded together so that the energy generating elements 18 provided on the fourth surface 2b of the second flow path substrate 2 are housed inside the housing portion 12 formed on the third flow path substrate 3.

[0042] The bonding is performed by bringing the second flow path substrate 2 into close contact with the adhesive layer transferred to the third flow path substrate 3, and applying a pressure of 5 kN to the adhesive layer while thermally curing the adhesive 190. At this time, by applying pressure and heat uniformly to the surface, minute irregularities that occur when the adhesive is transferred can be crushed, and a bonding layer 19 with few air bubbles can be obtained.

[0043] 5(d) shows a state in which pressure chambers 14 opening to the third surface 2a of the second flow path substrate 2 have been formed, and adhesive 170 has been transferred to the third surface 2a. The pressure chambers 14 can be formed by dry etching or the like. The pressure chambers 14 are formed so as to communicate with the flow paths formed in the third flow path substrate 3. The adhesive 170 is transferred after the pressure chambers 14 have been formed.

[0044] 5(e) shows a state in which the first flow path substrate 1 and the second flow path substrate 2 are bonded together. The second surface 1b of the first flow path substrate 1 and the third surface 2a of the second flow path substrate 2 are bonded together via an adhesive 170, and a bonding layer 17 is formed between the first flow path substrate 1 and the second flow path substrate 2. The bonding is performed in the same manner as the bonding of the second flow path substrate 2 and the third flow path substrate 3. By bonding the first flow path substrate 1 and the second flow path substrate 2, the element substrate 100 is completed.

[0045] In the second flow path substrate 2, a portion of the third flow path substrate 3 is hollowed out corresponding to the PAD 13 to expose the PAD 13 to which the wire 22 will be connected in a later wire bonding process. That is, when viewed in the first direction D1, there is a portion of the PAD 13 that does not overlap with the third flow path substrate 3. In this configuration, in the bonding process of the first flow path substrate 1 and the second flow path substrate 2, pressure may be applied while supporting the first surface 1a of the first flow path substrate 1 and the sixth surface 3b of the third flow path substrate 3. Then, when the first flow path substrate 1 is brought into close contact with the second flow path substrate 2 and pressure is applied, pressure is not easily applied to the portion where the third flow path substrate 3 is not present and that overlaps with the PAD 13 in the first direction D1. Therefore, in the portion of the bonding layer 17 where the third flow path substrate 3 is not located directly below and above the PAD 13, the unevenness of the transferred adhesive 170 cannot be completely crushed, and air bubbles are relatively likely to form.

[0046] However, in the first embodiment, a step portion 21 including a plurality of steps 20 is provided between the second surface 1b and the third surface 2a, that is, in the portion of the bonding layer 17 where the third flow path substrate 3 is not located directly below or directly above the PAD 13. This step portion 21 prevents large bubbles from being generated and prevents the bubbles from migrating inside the sealing resin 23 in a later process. The effect of the step portion 21 in suppressing the size of bubbles and preventing their migration will be described in detail later.

[0047] 5(f) shows the element substrate 100 and the wiring substrate 70 placed on the jig 90. After the element substrate 100 is completed, the element substrate 100 is electrically connected to the wiring substrate 70 via the PAD 13. The element substrate 100 and the wiring substrate 70 are connected in a state where the wiring substrate 70 is placed on the jig 90.

[0048] 5(g) shows a state in which the wire 22 is connected to the element substrate 100 and the wiring substrate 70, and the element substrate 100 and the wiring substrate 70 are electrically connected to each other. By wire bonding, one end of the wire 22 is connected to the PAD 13 of the element substrate 100, and the other end is connected to an external terminal provided on the wiring substrate 70.

[0049] 5(h) shows the wires 22 covered with the sealing resin 23. The sealing resin 23 is hardened by being heated for a certain period of time. The sealing resin 23 is provided to cover the exposed portion of the PAD 13 and the external terminals of the wiring substrate 70 in order to protect not only the wires 22 but also the PAD 13 and the wiring substrate 70. Furthermore, the sealing resin 23 is provided to cover at least the end face of the second flow path substrate 2 and the end of the bonding layer 17 among the end faces of the element substrate 100 on the wiring substrate 70 side in the third direction D3.

[0050] When heat is transferred to the element substrate 100 during hardening of the sealing resin 23, if there are air bubbles communicating with the end of the bonding layer 17 of the element substrate 100, the internal pressure of the air bubbles may increase and the air bubbles may be released into the sealing resin 23. However, in the first embodiment, the step 20 is provided along the end face of the element substrate 100 facing the wiring substrate 70, and therefore it is possible to prevent air bubbles from being generated at positions that may come into contact with the sealing resin 23 and moving into the sealing resin 23.

[0051] 5(i) shows the state after the jig 90 has been removed. After the sealing resin 23 has hardened, the jig 90 is removed from the wiring board 70. After that, the wiring board 70 is fixed to the housing 60, ink is injected into the housing 60, and so on, and the liquid ejection head 50 is completed.

[0052] (Stepped part) Next, a detailed description will be given of the configuration and effects of the step portion 21 in the first embodiment. Fig. 6 is a cross-sectional view showing a state in which a bubble 30 is generated in the bonding layer 17 of the element substrate 100 according to the first embodiment.

[0053] First, the dimension of the step 20 in the height direction will be described by way of example. In the first embodiment, the thickness of the bonding layer 17, i.e., the distance between the second surface 1b of the first flow path substrate 1 and the third surface 2a of the second flow path substrate 2, is set to 5 μm or more and 6 μm or less. The height of the step 20 is set to approximately 5 μm so that the distance from the step 20 to the third surface 2a is 0.1 μm or more and 0.3 μm or less. In this way, the height of the step 20 is set so that the distance between the step 20 and the third surface 2a is extremely smaller (for example, 1 / 10 or less) than the distance between the second surface 1b and the third surface 2a.

[0054] During the process of joining the first flow path substrate 1 and the second flow path substrate 2, heat is applied to the adhesive 170 for hardening, and the viscosity of the adhesive decreases. In the first embodiment, the flow resistance of the adhesive 170 is higher in the portion where the step 20 is provided than in the portion where the step 20 is not provided. This is because the distance between the step 20 and the third surface 2a is narrower than the distance between the second surface 1b and the third surface 2a. Therefore, if bubbles 30 are generated during the bonding process, the bubbles 30 will not move between the step 20 and the third surface 2a, but will remain in the thicker portion of the bonding layer 17 where the step 20 between the second surface 1b and the third surface 2a is not provided and where the flow resistance is lower.

[0055] In the first embodiment, three rows of steps each including a plurality of steps 20 aligned in the second direction D2 are provided at positions overlapping the PAD 13 at the end of the first flow path substrate 1 in the first direction D1. Therefore, bubbles 30 generated in the bonding process are trapped between the steps 20 in the second direction D2 and the third direction D3. That is, in the first embodiment, even if bubbles 30 are generated, the bubbles 30 are separated by the steps 20, and therefore, the generation of bubbles 30 having a size equal to or larger than the distance between adjacent steps 20 is suppressed.

[0056] In this way, the step 20 is disposed inside the bonding layer 17 at a position overlapping in the third direction D3 with the PAD 13 disposed on the fourth surface 2b of the second flow path substrate 2, so that voids are not generated in the portion communicating with the chip end, and air bubbles are not released into the sealant near the wires to be bonded during mounting in the next process, thereby reducing the impact of air bubbles on the bonding surface on the next process.

[0057] In the first embodiment, the distance from the step 20 to the third surface 2a was 0.1 μm or more and 0.3 μm or less, and the height of the step 20 was approximately 5 μm. However, application of the present invention is not limited to such a configuration. In this structure, the thickness of the bonding layer 17 after the bonding process, particularly the thickness of the bonding layer 17 at the location of the step 20, depends on the height of the step 20. Furthermore, the thickness of the adhesive 170 transferred to the bonding surface varies depending on the type of adhesive and the condition of the bonding surface, and can be set within a range of 0.5 μm or more and 10 μm or less. For example, if the thickness of the adhesive 170 is significantly smaller than the distance between the second surface 1b and the third surface 2a, and the distance between the step 20 and the third surface 2a is small, the adhesive may not sufficiently spread between the second surface 1b and the third surface 2a. This may actually induce the formation of air bubbles 30, reducing the bonding strength of the bonding surface. Therefore, the height of the step 20 should be set appropriately taking into consideration the distance between the bonding surfaces, the thickness of the adhesive, etc. Specifically, it is desirable that the height of the step 20 be set between 0.1 μm and 5 μm.

[0058] Next, the dimensions of the gaps between the steps 20 will be described by way of example. Figures 7(a) and 7(b) are transparent plan views of the element substrate 100 when viewed in a direction perpendicular to the second surface 1b, showing only the main components such as the step portion 21. Two configuration examples of the step portion 21 will be described below in order with reference to Figures 7(a) and 7(b).

[0059] 7(a) shows an example in which the step portion 21 provided on the first flow path substrate 1 is configured with two step rows. Of the steps 20 that make up the step portion 21, the steps will be referred to as step 20a and step 20b in order of proximity to the end face (scribe line) of the first flow path substrate 1 in the third direction D3. That is, the first flow path substrate 1 is provided with a first step row in which the steps 20a are arranged at equal intervals in the second direction D2, and a second step row in which the steps 20b are arranged at equal intervals in the second direction D2, lined up side by side in the third direction D3.

[0060] The thickness of the bonding layer 17 between the steps 20 and the third surface 2a, which is the bonding surface, is thin, and bubbles 30 are unlikely to exist therein. Therefore, if bubbles 30 are generated, they move to areas where there are no steps 20. In other words, since bubbles 30 are located in spaces surrounded by multiple steps 20, the size of the bubbles 30 contributes to the size of the spaces between the steps 20. In this way, by providing a step portion 21 made up of multiple steps 20, the size of the generated bubbles 30 can be controlled to be equal to or smaller than the spaces between the steps 20.

[0061] 7(a), the PADs 13 are rectangular with the longitudinal direction in the third direction D3 and have a size of 50 μm × 500 μm. The PADs 13 are arranged at equal intervals in the second direction D2, and the distance L1 between the PADs 13 in the second direction D2 is 30 μm.

[0062] The diameter of the wires 22 connected to each PAD 13 is 20 μm. The wires 22 are arranged approximately at the center of the PAD 13 in the second direction D2, and the distance L2 between the wires 22 in the second direction D2 is approximately 60 μm, which is greater than the distance L1.

[0063] When viewed in the first direction D1, the step 20 has a rectangular shape with its longitudinal direction aligned in the third direction D3 and measures 70 μm x 200 μm. The center line of the step 20a in the second direction D2 is aligned with the center line of the PAD 13. Therefore, the distance L3 between the steps 20a in the second direction D2 is 10 μm. The distance between the steps 20b in the second direction D2 is also L3.

[0064] The distance in the third direction D3 between the steps 20a and 20b may be set appropriately taking into consideration the size of the bubbles 30 and the fluidity of the adhesive 170. For example, if the adhesive 170 sufficiently spreads over the entire bonding surface, the distance may be set to zero, and the steps 20a and 20b may be formed so as to be connected in the third direction D3.

[0065] 7(a) shows a state in which a bubble 30a is formed in a space surrounded by two steps 20a and one step 20b, and a bubble 30b is formed in a space surrounded by one step 20a and two steps 20b. The bubble 30a faces the end face of the first flow path substrate 1, and the bubble 30b is located inside the first flow path substrate 1 with respect to the steps 20a.

[0066] In this configuration example, the size of the air bubbles 30a is limited to approximately 10 μm × 200 μm at most. When the height of the step 20 is 5 μm, the size of the air bubbles 30 released into the sealing resin 23 is approximately 27 μm at most. Because the distance between adjacent wires 22 is approximately 60 μm, even if the air bubbles 30 come into contact with the wires 22, the wires 22 will not be broken or shorted, and defects caused by the air bubbles 30 can be suppressed.

[0067] Furthermore, in this configuration example, the step 20a and the center line of the wire 22 in the second direction D2 substantially coincide with each other, so the bubble 30a is formed and released in the center between adjacent wires 22. This reduces the chance that the bubble 30a will come into contact with the wire 22 in the first place. In other words, according to this configuration example, by making the size of the bubble 30a smaller than the space between the wires 22 and controlling it so that it is generated in a place where there is no wire 22, it is possible to avoid problems caused by the bubble 30 coming into contact with the wire 22.

[0068] In this way, it is desirable to set the distance L3 in the second direction D2 between the steps 20 so that the bubbles 30 are small enough not to cause any problems. Specifically, it is preferable to set the distance L3 smaller than the distance L1 in the second direction D2 between the pads 13 and the distance L2 in the second direction D2 between the wires 22.

[0069] 7(a), the steps 20a and 20b are staggered so that they are alternately arranged in the second direction D2. This configuration prevents the bubbles 30 from growing larger in the third direction D3. Furthermore, since the adhesive 170 is filled between the steps 20, the adhesive strength required for bonding the substrates is maintained sufficiently, ensuring reliable bonding of the substrates. Furthermore, this configuration reduces ultrasonic wave conduction loss and prevents a decrease in bonding strength when ultrasonic waves are applied to bond the wire 22 to the PAD 13 in a process subsequent to the bonding process.

[0070] The bubble 30b formed inside the step 20a faces the end surface of the first flow path substrate 1. Therefore, the bubbles 30 do not move into the sealing resin 23. By providing the step 20 at the end of the first flow path substrate 1 in this way, it is possible to obtain the effect of preventing the movement of the bubbles 30 itself.

[0071] FIG. 7(b) shows an example in which the step portion 21 provided on the first flow path substrate 1 is configured as a single row of steps. In this configuration example, the distance L1 between the PADs 13, the distance L2 between the wires 22, and the distance L3 between the steps 20 are all the same as those in the configuration example shown in FIG. 7(a). Even with this configuration, it is possible to suppress the size of the bubbles 30 and their migration into the sealing resin 23, compared to a configuration in which the step portion 21 is not provided. Therefore, for example, if the distance from the energy generating element 18 to the end face of the element substrate 100 is short and it is difficult to arrange multiple step rows side by side, the step portion 21 configured as a single row of steps may be provided to suppress defects caused by the bubbles 30. Furthermore, if sufficient bonding strength can be obtained, the step portion 21 may be configured as a single step that is long in the second direction D2, such that multiple steps 20 are connected in the second direction D2, to prevent the bubbles 30 from being released into the sealing resin 23.

[0072] Second Embodiment Next, a second embodiment of the present invention will be described. The second embodiment differs from the first embodiment in the configuration of the step portion. Only the differences between the second embodiment and the first embodiment will be described below. Components in the second embodiment that are similar to those in the first embodiment will be assigned the same reference numerals and will not be described again.

[0073] 8 is a cross-sectional view of the element substrate 120 according to the second embodiment when viewed in the second direction D2, and shows the internal configuration of the element substrate 120. In the first embodiment, the step portion 21 is formed by a plurality of steps 20 provided on the second surface 1b of the first flow path substrate 1, but the step portion 25 according to the second embodiment is formed by a plurality of steps 24 provided on the third surface 2a of the second flow path substrate 2.

[0074] The step portion 25 is provided at an end portion of the second flow path substrate 2 on the side 2b1 closer to the wiring substrate 70, and includes a plurality of step rows each formed by arranging a plurality of steps 24 in the second direction D2. The end face on the side 2b1 side of the step 24 of the step row provided at the position closest to the side 2b1 is formed on the same plane as the end face of the second flow path substrate 2 on the side 2b1 side.

[0075] The step 24 can be formed, for example, by etching the second flow path substrate 2. In this case, the third surface 2a of the second flow path substrate 2 becomes a recessed surface that is recessed by etching. The step 24 is formed so as to protrude from the third surface 2a toward the second surface 1b of the first flow path substrate 1. In the second embodiment, the pressure chamber 14 is formed at a position deeper than the third surface 2a of the second flow path substrate 2, i.e., on the side closer to the third flow path substrate 3.

[0076] In the bonding process, adhesive 170 is filled on third surface 2a, i.e., in recesses formed by steps 24, and the second surface 1b of first flow path substrate 1 and the third surface 2a of second flow path substrate 2 are bonded together. At this time, both substrates may be bonded together so that step 24 abuts against second surface 1b of first flow path substrate 1, or both substrates may be bonded together so that step 24 faces second surface 1b and is spaced apart from second surface 1b. In either case, bonding layer 17 is formed so that the distance between second surface 1b of first flow path substrate 1 and third surface 2a of second flow path substrate 2 is greater than the distance between second surface 1b and step 24.

[0077] 9 is a cross-sectional view showing the details of the step portion 25 according to the second embodiment. The third surface 2a of the second flow path substrate 2 is formed inside the scribed end of the second flow path substrate 2 so as not to overlap the scribed region. In this way, the step 24 can be formed with a sufficient height, When air bubbles are generated in the recessed portion between the steps 24, it is possible to prevent the air bubbles from moving between the steps 24 where the thickness of the bonding layer 17 is thin and the second surface 1b of the first flow path substrate 1. Therefore, it is possible to prevent the air bubbles from being released into the sealing resin 23 from the end portion of the bonding layer 17.

[0078] 10(a) to 10(c) are explanatory diagrams illustrating how bubbles 30 are released into the sealing resin 23. FIG. 10(a) shows a state in which bubbles 30 that communicate with the scribe region are generated at the end of the bonding layer 17. FIG. 10(b) shows how the sealing resin 23 is filled in a comparative example in which the distance between the second surface 1b and the third surface 2a is increased compared to the second embodiment. FIG. 10(c) shows how the sealing resin 23 is filled in the second embodiment.

[0079] When the sealing resin 23 is filled so as to cover the end of the bonding layer 17, the heated air bubbles 30 expand when the sealing resin 23 hardens, and some of them are released into the sealing resin 23. At this time, the sealing resin 23 in an amount equivalent to the accumulation of the released air bubbles 30 enters the bonding layer 17 in place of the air bubbles 30. As shown in FIG. 10(b), if large-sized air bubbles 30 are released into the sealing resin 23, there is a high possibility that a malfunction will occur.

[0080] On the other hand, in the second embodiment, the adhesive 170 is compressed so that the distance between at least the step 24 and the second surface 1b is 0.3 μm or less, thereby forming the bonding layer 17. With this configuration, the rate at which the air bubbles 30 released into the sealing resin 23 are replaced by the sealing resin 23 that enters between the step 24 and the second surface 1b decreases. When the viscosity of the sealing agent increases due to thermal curing of the sealing resin 23, the air bubbles 30 in the bonding layer 17 are no longer replaced by the sealing resin 23, and the release of the air bubbles 30 into the sealing resin 23 is suppressed. In this way, in the second embodiment, the distance between the step 24 and the second surface 1b is set to a degree that can suppress the volume of the air bubbles 30 released into the sealing resin 23.

[0081] In the second embodiment, the end face (first end face) of the step 24 is formed flush with the end face (second end face) of the second flow path substrate 2 at the end on the side covered with the sealing resin 23, but this configuration is not limited to this. For example, even if the third surface 2a of the second flow path substrate 2 is formed at a position overlapping the scribe line and the end face of the step 24 is formed inside the end face of the second flow path substrate 2, the size of the bubble 30 depends on the distance in the third direction D3 between the end face of the step 24 and the end face of the second flow path substrate 2. Therefore, the element substrate 200 may be configured by setting the distance from the end face of the step 24 to the end face of the second flow path substrate 2 so that the size of the bubble 30 can be reduced to a level that does not affect the wire bonding strength.

[0082] For example, if the strength standard for wire bonding is 100mN, the volume is 5 to 10mm. 3 If bubbles of this size or larger come into contact, they may be broken by the buoyancy of the bubbles in the sealing resin. If the accumulation of bubbles is 1 / 1000 or less, it can be said that there is almost no damage due to contact. Therefore, the volume of bubbles in the sealing resin is set to 0.005 mm 3If the contact load can be kept below this value, it can be said that there is almost no effect from the contact load. For example, consider a case where a semicircular bubble with a radius equal to the distance from the end face of the step 24 to the end face of the second flow path substrate 2 is formed at the end of the bonding layer 17 on the side covered with the sealing resin 23. In this case, if the thickness of the bonding layer 17 is 5 μm, it is desirable that the distance in the third direction D3 from the end face (first end face) of the step 24 to the end face (second end face) of the second flow path substrate 2 be 200 μm or less.

[0083] Also in the configuration of the second embodiment, the size of bubbles generated in the bonding layer 17 can be reduced and the bubbles can be prevented from migrating into the sealing resin 23, thereby reducing the occurrence of defects caused by the bubbles. That is, the step portion provided to prevent defects from occurring may be provided in at least one of the first flow path substrate 1 and the second flow path substrate 2. Alternatively, for example, the step portion disposed in the bonding layer 17 may be configured by providing a step in both the first flow path substrate 1 and the second flow path substrate 2.

[0084] <Other embodiments> Next, as another embodiment of the present invention, a configuration in which the arrangement positions of the step portion, PAD, and wire are changed will be described. Hereinafter, only the differences between the configuration of the other embodiment and the configuration of the first embodiment will be described. In the configuration of the other embodiment, the same components as those in the first embodiment will be assigned the same reference numerals, and the description will be omitted.

[0085] In the first embodiment, the step portions 21 were provided at both ends of the first flow path substrate 1 in the third direction D3. The step portions 21 were configured so that the steps 20 overlapped all of the PADs 13 provided on the second flow path substrate 2 in the first direction D1. However, application of the present invention is not limited to this configuration; for example, the same effect can be achieved by partially arranging steps in areas where connection wiring is densely packed. Therefore, with reference to FIGS. 11(a) to 11(e), examples of the arrangement of the PADs 13 and the steps 20 in other embodiments will be described. FIGS. 11(a) to 11(e) are transparent plan views showing the positional relationship between the PADs 13 and the steps 20 in other embodiments.

[0086] 11(a) shows an example in which a plurality of PADs 13 are provided along one of the long sides of an element substrate 140 that has a rectangular shape when viewed in the first direction D1, and across substantially the entire longitudinal area of ​​the element substrate 140. In this example, wires 22 connected to each PAD 13 are arranged across the long side from the inside to the outside of the element substrate 140, and the arrangement direction of the PADs 13 and the extension direction of the wires 22 are substantially perpendicular to each other.

[0087] 11(a), in a configuration in which the PADs 13 are arranged in a row and the wires 22 connected to the PADs 13 extend in a direction intersecting (perpendicular to) the arrangement direction of the PADs 13, it is preferable to provide a step 20 corresponding to each PAD 13. This is because it is possible to effectively prevent air bubbles from moving near the wires 22 and prevent large-sized air bubbles from being generated. Therefore, in this example, two rows of steps are provided along the arrangement direction of the PADs 13 (long sides of the element substrate 140) so that each PAD 13 and at least one step 20 overlap in the first direction D1. In other words, the steps 20 are arranged over substantially the entire area of ​​the element substrate 140 in the longitudinal direction.

[0088] 11(b) shows an example in which a plurality of PADs 13 are provided along two short sides of the element substrate 140, over substantially the entire area in the short direction perpendicular to the longitudinal direction of the element substrate 140. In this example, the wires 22 connected to each PAD 13 are arranged across the short sides from the inside to the outside of the element substrate 140, and the arrangement direction of the PADs 13 and the extension direction of the wires 22 are substantially perpendicular to each other.

[0089] In this example as well, it is preferable to provide a step 20 corresponding to each PAD 13 in order to suppress the size of air bubbles and prevent air bubbles from coming into contact with the wires 22. Therefore, in this example, two rows of steps are provided along the arrangement direction of the PADs 13 (the short side of the element substrate 140) so that each PAD 13 and at least one step 20 overlap in the first direction D1. In other words, the steps 20 are arranged over substantially the entire area of ​​the element substrate 140 in the short direction.

[0090] 11(c) shows an example in which a plurality of PADs 13 are provided along one of the long sides of the element substrate 140 in a part of the longitudinal direction of the element substrate 140. In this example, the wires 22 connected to each PAD 13 are arranged across the short side from the inside to the outside of the element substrate 140, and the arrangement direction of the PADs 13 and the extension direction of the wires 22 are approximately perpendicular to each other.

[0091] In this example, it is also preferable to provide a step 20 corresponding to each PAD 13 in order to suppress the size of the air bubbles and to prevent the air bubbles from contacting the wire 22. Two rows of steps are provided along the arrangement direction of the PADs 13 (short sides of the element substrate 140) so that the PADs 13 and at least one step 20 overlap in the first direction D1. On the other hand, in this configuration, it is not necessary to form the step portion 21 over the entire area of ​​the element substrate 140 in the longitudinal direction, and it is sufficient that the steps 20 are arranged corresponding to the PADs 13.

[0092] 11(a) to 11(c), the arrangement direction of the PADs 13 and the extension direction of the wires 22 intersect, and the sides along which the PADs 13 are arranged coincide with the sides straddled by the wires 22. In such a configuration, by providing steps 20 at positions overlapping with the first direction D1 for each PAD 13, it is possible to suitably prevent problems caused by air bubbles even when the wires 22 are covered with the sealing resin 23.

[0093] Figures 11(a), (b), and (c) show a state in which a step is placed at a position opposite the PAD, and Figures 11(d) and (e) show a state in which a step is placed only at a part of the position opposite the PAD.

[0094] 11(d) shows an example in which a plurality of PADs 13 are provided along one of the long sides of the element substrate 140 in a part of the longitudinal direction of the element substrate 140. In this example, the wires 22 connected to each PAD 13 are arranged from the inside to the outside of the element substrate 140, straddling the short side adjacent to the long side, and the arrangement direction of the PADs 13 and the extension direction of the wires 22 are approximately parallel.

[0095] In this example, in order to reduce the size of bubbles and prevent bubbles from contacting the wire 22, it is preferable that the step portion 21 be provided along the short side across which the wire 22 spans. This is because, in order to prevent defects, it is more important to prevent bubbles from being released toward the short side across which the wire 22 spans than to prevent bubbles from being released toward the long side across which the wire 22 does not span. Therefore, in this example, the step portion 21 is configured so that the step 20 overlaps with the first direction D1 only for some of the PADs 13. More specifically, the multiple step portions 20 overlap with the first direction D1 for the PAD 13 that is located closest to the side across which the wire 22 spans among the multiple PADs 13. In this way, the arrangement direction of the step 20 can be configured to intersect with the arrangement direction of the PADs 13 depending on the arrangement direction of the PADs 13 and the extension direction of the wire 22.

[0096] 11(e) shows an example in which a plurality of PADs 13 are provided along one of the long sides of the element substrate 140 in a part of the longitudinal direction of the element substrate 140. In this example, the wires 22 connected to each PAD 13 are arranged across the long side from the inside to the outside of the element substrate 140, and the arrangement direction of the PADs 13 and the extension direction of the wires 22 are approximately perpendicular to each other.

[0097] Depending on the configuration and size of the element substrate, there may be a bias in the locations where bubbles are likely to occur or where bubbles are likely to grow larger. In such a configuration, it may be possible to arrange the step portion 21 only in some locations in order to suppress the occurrence and size of bubbles. This is because excessive increase in the step 20 may reduce the bonding strength between the substrates. For example, in a configuration in which bubbles are likely to occur near the center of the long side of the element substrate 140, the step portion 21 may be provided only in the center of the long side, as shown in FIG. 11( e). Even in such a case, the step portion 21 may be configured so that the step 20 overlaps only some of the pads 13 in the first direction D1.

[0098] It is desirable that the distance between the step and the substrate facing the step be 0.1 μm or more from the viewpoint of adhesive strength between the substrates. This is because if the adhesive layer between the step and the substrate is extremely thin, the adhesive strength will decrease. Furthermore, to ensure sufficient adhesive strength between the substrates when bonded, it is desirable that the area of ​​the adhesive surface without the step be larger than the area of ​​the step.

[0099] In the above-described embodiment, all of the steps constituting the step portion are formed on a rectangular parallelepiped, but this is not limited to this configuration. For example, the steps may be circular or square when viewed in the protruding direction (first direction D1). Furthermore, all of the steps constituting the step portion do not need to have the same shape, and the spacing between the steps does not need to be constant; the shape and spacing can be changed as appropriate.

[0100] The disclosure of this embodiment includes the following configuration. (Configuration 1) a first flow path substrate having a first surface on which a discharge port for discharging a liquid is formed and a second surface opposite to the first surface; a second flow path substrate having a third surface joined to the second surface of the first flow path substrate and a fourth surface opposite to the third surface, the second flow path substrate including a flow path for supplying the liquid to be ejected from the ejection port to the first flow path substrate, an energy generating element that generates energy for ejecting the liquid, and a connection terminal provided on the fourth surface for supplying electricity to the energy generating element; a bonding layer between the second surface and the third surface, the bonding layer bonding the second surface and the third surface; an element substrate comprising: a wiring board having external terminals electrically connected to the connection terminals; an electrical connection portion that electrically connects the connection terminal and the external terminal; a sealing resin fixed so as to cover the electrical connection portion and an end portion of the fourth surface of the bonding layer; Equipped with A liquid ejection head characterized in that a step is provided between the second surface and the third surface, protruding from at least one of the second surface and the third surface, and positioned so as to overlap with the connection terminal when viewed in a first direction perpendicular to the fourth surface. (Configuration 2) a plurality of the connection terminals and a plurality of the steps are arranged side by side in a second direction along a side of the end of the fourth surface, 2. The liquid ejection head according to configuration 1, wherein, when viewed in the first direction, at least one of the steps overlaps each of the plurality of connection terminals. (Configuration 3) the plurality of connection terminals and the plurality of steps are respectively arranged at equal intervals in the second direction; The liquid ejection head according to configuration 2, wherein the distance between adjacent steps in the second direction is smaller than the distance between adjacent connection terminals. (Configuration 4) The liquid ejection head according to any one of configurations 1 to 3, wherein the electrical connection portion is a wire arranged across a side of the fourth surface of the second flow path substrate. (Configuration 5) The plurality of steps are arranged at equal intervals in the second direction, the electrical connection portions are arranged at equal intervals in the second direction so as to be connected to the respective connection terminals; The liquid ejection head according to configuration 2 or 3, wherein the distance between adjacent steps in the second direction is smaller than the distance between adjacent electrical connection portions. (Configuration 6) The plurality of steps are arranged side by side in a second direction along the edge of the end of the fourth surface, the plurality of connection terminals are arranged side by side in a third direction along a side adjacent to the side of the fourth surface, A liquid ejection head as described in configuration 1, characterized in that, when viewed in the first direction, the multiple steps overlap the connection terminal among the multiple connection terminals that is located closest to the edge of the end of the fourth surface. (Configuration 7) a plurality of the connection terminals and a plurality of the steps are arranged side by side in a second direction along a side of the end of the fourth surface, 2. The liquid ejection head according to configuration 1, wherein, when viewed in the first direction, the step overlaps only some of the plurality of connection terminals. (Configuration 8) a plurality of the connection terminals are arranged side by side in a second direction along the edge of the end of the fourth surface, 2. The liquid ejection head according to configuration 1, wherein the step overlaps with a plurality of the connection terminals when viewed in the first direction. (Configuration 9) a first step row in which the plurality of steps are aligned in a second direction along the side of the fourth surface; and a second step row in which the plurality of steps are aligned in the second direction and which is disposed adjacent to the first step row; Equipped with The liquid ejection head according to configuration 1, wherein the steps of the first step row and the steps of the second step row are alternately arranged in the second direction. (Configuration 10) 10. The liquid ejection head according to any one of configurations 1 to 9, wherein the height of the step in the first direction is 5 μm or less. (Configuration 11) 11. The liquid ejection head according to configuration 10, wherein the distance between the step and the surface facing the step is 0.1 μm or more and 0.3 μm or less. (Configuration 12) A liquid ejection head described in any one of configurations 1 to 5, characterized in that a first end face on the end side of the fourth surface of the step is formed on the same plane as a second end face on the end side of the fourth surface of the second flow path substrate. (Configuration 13) a first end face of the step on the end side of the fourth surface is located more inward of the second flow path substrate than a second end face of the step on the end side of the fourth surface of the second flow path substrate, 6. The liquid ejection head according to any one of configurations 1 to 5, wherein the distance from the first end face to the second end face is 200 μm or less. (Configuration 14) A liquid ejection head described in any one of configurations 1 to 13, characterized in that on the second surface and the third surface on which the step is provided, the area of ​​the region where the step is not provided is smaller than the area of ​​the region where the step is provided. (Configuration 15) 15. The liquid ejection head according to any one of configurations 1 to 14, wherein the energy generating element is a heat generating element. (Configuration 16) 15. The liquid ejection head according to any one of configurations 1 to 14, wherein the energy generating element is a piezoelectric element. (Configuration 17) 15. The liquid ejection head according to any one of configurations 1 to 14, wherein the energy generating element is provided on the fourth surface. [Explanation of symbols]

[0101] 1...first flow path substrate, 1a...first surface, 1b...second surface, 2...second flow path substrate, 2a...third surface, 2b...fourth surface, 13...PAD (connection terminal), 16...discharge port, 17...bonding layer, 18...energy generating element, 20...step, 22...wire (electrical connection portion), 23...sealing resin, 50...liquid discharge head, 70...wiring substrate, 100...element substrate

Claims

1. a first flow path substrate having a first surface on which a discharge port for discharging a liquid is formed and a second surface opposite to the first surface; a second flow path substrate having a third surface joined to the second surface of the first flow path substrate and a fourth surface opposite to the third surface, the second flow path substrate including a flow path for supplying the liquid to be ejected from the ejection port to the first flow path substrate, an energy generating element that generates energy for ejecting the liquid, and a connection terminal provided on the fourth surface for supplying electricity to the energy generating element; a bonding layer between the second surface and the third surface, the bonding layer bonding the second surface and the third surface; an element substrate comprising: a wiring board having external terminals electrically connected to the connection terminals; an electrical connection portion that electrically connects the connection terminal and the external terminal; a sealing resin fixed so as to cover the electrical connection portion and an end portion of the fourth surface of the bonding layer; Equipped with A liquid ejection head characterized in that a step is provided between the second surface and the third surface, protruding from at least one of the second surface and the third surface, and positioned so as to overlap with the connection terminal when viewed in a first direction perpendicular to the fourth surface.

2. the plurality of connection terminals and the plurality of steps are arranged side by side in a second direction along a side of the end of the fourth surface, 2. The liquid ejection head according to claim 1, wherein at least one of the steps overlaps each of the plurality of connection terminals when viewed in the first direction.

3. the plurality of connection terminals and the plurality of steps are respectively arranged at equal intervals in the second direction; 3. The liquid ejection head according to claim 2, wherein the distance between adjacent steps in the second direction is smaller than the distance between adjacent connection terminals.

4. The liquid ejection head according to claim 1 , wherein the electrical connection portion is a wire disposed across a side of the fourth surface of the second flow path substrate.

5. The plurality of steps are arranged at equal intervals in the second direction, the electrical connection portions are arranged at equal intervals in the second direction so as to be connected to the respective connection terminals; 3. The liquid ejection head according to claim 2, wherein the distance between adjacent steps in the second direction is smaller than the distance between adjacent electrical connection portions.

6. The plurality of steps are arranged side by side in a second direction along the edge of the end of the fourth surface, the plurality of connection terminals are arranged side by side in a third direction along a side adjacent to the side of the fourth surface, A liquid ejection head as described in claim 1, characterized in that, when viewed in the first direction, the multiple steps overlap the connection terminal among the multiple connection terminals that is located closest to the side of the end of the fourth surface.

7. the plurality of connection terminals and the plurality of steps are arranged side by side in a second direction along a side of the end of the fourth surface, 2. The liquid ejection head according to claim 1, wherein, when viewed in the first direction, the step overlaps only some of the plurality of connection terminals.

8. the plurality of connection terminals are arranged side by side in a second direction along the edge of the end of the fourth surface, The liquid ejection head according to claim 1 , wherein the step overlaps with a plurality of the connection terminals when viewed in the first direction.

9. a first step row in which the plurality of steps are aligned in a second direction along the side of the fourth surface; and a second step row in which the plurality of steps are aligned in the second direction and which is disposed adjacent to the first step row; Equipped with The liquid ejection head according to claim 1 , wherein the steps of the first step row and the steps of the second step row are alternately arranged in the second direction.

10. 2. The liquid ejection head according to claim 1, wherein the height of the step in the first direction is 5 [mu]m or less.

11. 11. The liquid ejection head according to claim 10, wherein the distance between the step and the surface facing the step is 0.1 [mu]m or more and 0.3 [mu]m or less.

12. 2. The liquid ejection head according to claim 1, wherein a first end surface of the step on the end side of the fourth surface is formed on the same plane as a second end surface of the second flow path substrate on the end side of the fourth surface.

13. a first end surface of the step on the end side of the fourth surface is located more inward of the second flow path substrate than a second end surface of the step on the end side of the fourth surface of the second flow path substrate, 2. The liquid ejection head according to claim 1, wherein the distance from the first end face to the second end face is 200 [mu]m or less.

14. 2. A liquid ejection head according to claim 1, wherein the area of ​​the region where the step is not provided on one of the second surface and the third surface is smaller than the area of ​​the region where the step is provided.

15. 2. The liquid ejection head according to claim 1, wherein the energy generating element is a heating element.

16. 2. The liquid ejection head according to claim 1, wherein the energy generating element is a piezoelectric element.

17. The liquid ejection head according to claim 1 , wherein the energy generating element is provided on the fourth surface.

Images