Element substrate and liquid discharge head

Abstract

To provide an element substrate for a liquid discharge head which suppresses deterioration in energy generation efficiency.SOLUTION: An element substrate 1 for a liquid discharge head which discharges liquid includes: a heating resistance element 2 which generates energy for discharging liquid by heat generation; wiring layers 7 for supplying an electric power to the heating resistance element 2; and a connection member 8 which has a first connection part 8At connected to the heating resistance element 2 and a second connection part 8Ab connected to the wiring layers 7, and electrically connects the heating resistance element 2 and the wiring layers 7. The connection member 8 extends such that a tip on the wiring layer 7 side is branched, and is connected with the wiring layer 7 at a plurality of the second connection parts 8Ab.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an element substrate for a liquid ejection head.

Background Art

[0002] As an apparatus provided with a liquid ejection head for ejecting a liquid, a recording apparatus that ejects ink onto a recording medium to perform recording is known. As one of the liquid ejection methods in such a recording apparatus, a thermal method is known. In the thermal method, for example, a thermal energy generated by a heating resistance element provided on an element substrate of the liquid ejection head induces a foaming phenomenon of the liquid, and this is used for liquid ejection.

[0003] As an element substrate of the liquid ejection head, a configuration including, in addition to a heating resistance element, a wiring layer for supplying current to the heating resistance element and a connection member for electrically connecting the heating resistance element and the wiring layer is known. Patent Document 1 discloses a configuration using a plug formed of tungsten or the like as the connection member.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the above-described configuration, since a plurality of connection members are positioned at intervals from each other, the current density in the vicinity of the connection member in the heating resistance element becomes sparse, and there is a possibility that the energy generation efficiency may decrease.

[0006] In view of the above problems, an object of the present invention is to provide an element substrate for a liquid ejection head that suppresses a decrease in energy generation efficiency.

Means for Solving the Problems

[0007] To achieve the above object, the element substrate of the present invention is an element substrate for a liquid ejection head that ejects a liquid, a heating resistance element that generates energy for ejecting the liquid by heating, a wiring layer for supplying power to the heating resistance element, a first connection part connected to the heating resistance element and a second connection part connected to the wiring layer, and a connection member that electrically connects the heating resistance element and the wiring layer, and is provided with the tip part on the wiring layer side of the connection member branches and extends, and is connected to the wiring layer at a plurality of the second connection parts. Also, to achieve the above object, the element substrate of the present invention is an element substrate for a liquid ejection head that ejects a liquid, a heating resistance element that generates energy for ejecting the liquid by heating, a wiring layer for supplying power to the heating resistance element, a first connection part connected to the heating resistance element and a second connection part connected to the wiring layer, and a connection member that electrically connects the heating resistance element and the wiring layer, and is provided with the area of the first connection part is larger than the area of the second connection part.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide an element substrate for a liquid ejection head that suppresses a decrease in energy generation efficiency.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Best Mode for Carrying Out the Invention

[0010] Hereinafter, with reference to the drawings, the embodiments for carrying out the present invention will be exemplarily and specifically described based on examples. Note that the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. That is, the scope of the present invention is not intended to be limited to the following embodiments.

[0011] In this specification, "recording" (sometimes referred to as "printing") refers not only to the case of forming significant information such as characters and figures, but also regardless of whether it is significant or not. Further, it also represents the case of forming an image, pattern, pattern, etc. on a recording medium widely or performing processing on the medium, regardless of whether it is manifested so that a human can perceive it visually.

[0012] Hereinafter, as an embodiment of the present invention, a configuration in which the present invention is applied to an inkjet recording apparatus that performs a recording operation by discharging ink as a liquid onto a recording medium will be described. However, the recording apparatus to which the present invention is applicable is not limited to an inkjet recording apparatus, and any recording apparatus that uses a liquid discharge head having a heating resistor element and performs a recording operation using a liquid discharge head that discharges a liquid may be used. For example, the recording apparatus may be a thermal transfer type recording apparatus such as a melting type or a sublimation type. Further, the recording apparatus may be, for example, a manufacturing apparatus for manufacturing a color filter, an electronic device, an optical device, a micro structure, etc. by a predetermined recording method. Further, the recording apparatus may be a device that forms a three-dimensional image from 3D data.

[0013] <Recording apparatus> First, the basic configuration of a recording apparatus 30 according to an embodiment of the present invention will be described. FIG. 1 is an external perspective view of the recording apparatus 30 according to the embodiment. The recording apparatus 30 is an inkjet recording apparatus that discharges ink to perform recording on a recording medium P.

[0014] The recording apparatus 30 includes an ink tank 31 as an ink storage unit for holding ink inside, and a recording head 32. The ink tank 31 and the recording head 32 are configured as one unit, and the unit is mounted on a carriage 34. The recording head 32 is a liquid discharge head that discharges the ink stored in the ink tank 31 onto the recording medium P to perform recording. The carriage 34 can reciprocate in a direction orthogonal to the conveyance direction of the recording medium P (the direction of the arrow in FIG. 1) by a drive unit 35.

[0015] The drive unit 35 includes a lead screw 35a and a guide shaft 35b extending in the moving direction of the carriage 34. The lead screw 35a is a screw hole of the carriage 34 (not shown) engages therewith, and the rotation thereof causes the carriage 34 to move. The drive unit 35 includes a motor 35c and a gear train 35d as a rotation mechanism of the lead screw 35a. The guide shaft 35b guides the movement of the carriage 34. At one end of the movement range of the carriage 34, an optical sensor 34b for detecting the detected piece 34a of the carriage 34 is arranged, and the detection result is used for the movement control of the carriage 34.

[0016] The conveyance unit 33 conveys the recording medium P in the conveyance direction. The conveyance unit 33 includes a motor (not shown) as a drive source and a conveyance roller (not shown) that rotates by the driving force of the motor, and the recording medium P is conveyed by the rotation of the conveyance roller. In the recording apparatus 30, the conveyance direction of the recording medium P is substantially orthogonal to the movement direction of the carriage 34 (recording head 32).

[0017] The recording apparatus 30 includes an internal power source 36 that supplies the power consumed by the recording apparatus 30, and a control circuit 37 that controls the recording apparatus 30. The control circuit 37 causes the movement of the recording head 32 due to the movement of the carriage 34 and the ejection of ink, and the conveyance of the recording medium P to be performed alternately to record an image on the recording medium P.

[0018] Figs. 2(a) and (b) are explanatory views of the recording head 32. Fig. 2(a) is a perspective view of the ink tank 31 and the recording head 32 configured as one unit. The ink tank 31 and the recording head 32 are separable at the position of the broken line. The recording head 32 is a liquid ejection head having a plurality of ink ejection ports 32a for ejecting ink. Fig. 2(b) is a sectional view of the recording head 32 showing the structure around the ink ejection port 32a.

[0019] The recording head 32 has a flow path forming member 32b and an element substrate 1 which is a substrate for a liquid ejection head. The flow path forming member 32b is provided on the element substrate 1 and forms ink ejection ports 32a, flow paths 32c for supplying ink to the respective ink ejection ports 32a, and a common liquid chamber 32d.

[0020] A plurality of heating resistance elements 2 corresponding to each ink ejection port 32a are provided on the element substrate 1. The heating resistance element 2 of the present embodiment is an element that generates energy for discharging a liquid (ink) by supplying power, and in particular, is an electrothermal conversion element. The electrothermal conversion element is heated by energization to foam the ink, and discharges the ink from the ink ejection port 32a with the foaming energy. The liquid discharge method of the recording head 32 is a thermal method that utilizes the thermal energy generated by the heating resistance element 2.

[0021] <Element substrate> Next, the basic configuration of the element substrate 1 will be described. FIG. 3 is a plan view and a partial enlarged view of the element substrate 1. The element substrate 1 is rectangular in plan view, and pad rows formed by a plurality of electrode pads 3 are formed at both ends in the longitudinal direction thereof. Note that the plan view of the element substrate 1 refers to the case where the element substrate 1 is viewed in a direction orthogonal to the surface on which the pad rows of the element substrate 1 are formed. The electrode pad 3 is an electrical contact with an external device (such as a control circuit).

[0022] An arrangement region 4 of the heating resistance elements 2 corresponding to the rows of the plurality of ink ejection ports 32a is formed at the center in the short direction orthogonal to the longitudinal direction of the element substrate 1. In FIG. 3, a plurality of arrangement regions 4 are indicated by a two-dot chain line. Further, FIG. 3 shows an enlarged view showing the periphery of the three heating resistance elements 2 arranged in one arrangement region 4. A region including one heating resistance element 2 can be called a pressure generation portion in terms of generating pressure for discharging ink, and it can also be said that three pressure generation portions are shown in FIG. 3. The arrangement region 4 can be called a pressure generation region in that such pressure generation portions are formed in a row in the longitudinal direction of the element substrate 1.

[0023] The element substrate 1 includes a wiring layer 7, a plug 8, and a conductive layer 10. The lower part of FIG. 3 In the partial enlarged view, the area where the wiring layer 7 is formed is indicated by a dotted line. In a plan view of the element substrate 1, on one end side of the heating resistance element 2 in the first direction D1, it is arranged at a position where the wiring layer 7 and a plurality of plugs 8 overlap, and on the other end side of the heating resistance element 2 in the first direction D1, it is also arranged at a position where the wiring layer 7 and a plurality of plugs 8 overlap. At both end sides of the heating resistance element 2 in the first direction D1, the plurality of plugs 8 are arranged side by side in the second direction D2 that intersects the first direction D1. In the present embodiment, the first direction D1 is parallel to the short side direction of the element substrate 1, and the second direction D2 is parallel to the long side direction of the element substrate 1. Also, the stacking direction of each layer of the element substrate 1 is a direction orthogonal to the first direction D1 and the second direction D2. Hereinafter, the wiring layer 7 and the plug 8 arranged on one end side of the heating resistance element 2 are referred to as the wiring layer 7A and the plug 8A, and the wiring layer 7 and the plug 8 arranged on the other end side of the heating resistance element 2 are referred to as the wiring layer 7B and the plug 8B, and will be described separately as necessary.

[0024] Referring to FIGS. 4(a) and 4(b), the configuration of the element substrate 1 will be described in more detail. Although details will be described later, FIG. 4(a) is a view showing the periphery of one heating resistance element 2 in a comparative example, and FIG. 4(b) is a cross-sectional view taken along line A-A of FIG. 4(a). The element substrate 1 is a laminate composed of a plurality of functional layers such as a substrate 5, an intermediate layer 6, an insulating layer 9, and a conductive layer 10 in order from the lower layer. Also, a heating resistance element 2 and plugs 8 are provided on the element substrate 1. In the following description, regarding the stacking direction of the laminate, for convenience, the substrate 5 side is referred to as the lower layer and the conductive layer 10 side is referred to as the upper layer, but this does not indicate the posture of the element substrate 1 during use.

[0025] The substrate 5 is, for example, a plate-shaped member made of Si (silicon). On the substrate 5, a circuit (not shown) for selectively driving each heating resistance element 2 is formed. The circuit includes a driving element composed of a semiconductor element such as a switching transistor.

[0026] The intermediate layer 6 has a wiring layer 7 and is formed on the substrate 5. The material of the wiring layer 7 is, for example, a material mainly composed of aluminum, and more specifically, for example, AlCu (copper aluminum). The thickness of the wiring layer 7 is about 0.2 μm to 1.0 μm, for example. The intermediate layer 6 constitutes a heat storage layer formed mainly of, for example, SiO. The upper surface of the intermediate layer 6 is a flat surface. Note that the element substrate 1 may have a plurality of heat storage layers in which wiring layers are embedded. The thickness of the portion of the intermediate layer 6 above the wiring layer 7 is about 0.5 μm to 2.0 μm, for example. Note that the intermediate layer 6 may have a configuration in which a plurality of heat storage layers in which wiring layers are embedded are provided.

[0027] The layer above the intermediate layer 6 includes a heating resistance element 2, an insulating layer 9, and a conductive layer 10. The heating resistance element 2 is, for example, a film having a thickness of about 10 to 100 nm and contains, for example, tantalum silicon nitride (TaSiN) as a main component. The heating resistance element 2 is disposed on the upper surface (surface) of the planarized intermediate layer 6.

[0028] Also, the heating resistance element 2 and the wiring layer 7 are connected by a plurality of plugs 8. The plug 8 is a connecting member formed to penetrate from the upper surface of the intermediate layer 6 to the wiring layer 7. The plug 8 includes, for example, a contact metal film in contact with the corresponding wiring layer 7, a barrier metal film, and a plug film which is a main component. The contact metal film can be formed of, for example, titanium (Ti) having a thickness of about 10 to 50 nm. The barrier metal film can be formed of, for example, titanium nitride (TiN) having a thickness of about 50 to 100 nm. Also, the plug film can be formed of a material such as tungsten (W), for example. The plug film is formed to have a film thickness sufficient to fill a hole opened in the intermediate layer 6 by etching.

[0029] The wiring layer 7A is disposed at a position overlapping with the first end portion of the heating resistance element 2 in the first direction D1, and the wiring layer 7B is disposed at a position overlapping with the second end portion opposite to the first end portion of the heating resistance element 2. The wiring layer 7A is connected to the heating resistance element 2 via the plug 8A, and the wiring layer 7B is connected to the heating resistance element 2 via the plug 8B. The supply of power to the heating resistance element 2 is performed, for example, by passing a current through the wiring layer 7A → plug 8A → heating resistance element 2 → plug 8B → wiring layer 7B. By flowing the current in this way, the heating resistance element 2 generates heat, and the ink supplied from the common liquid chamber 32d serving as the supply port foams, and the ink is discharged from the ink discharge port 32a.

[0030] The insulating layer 9 is covered over the entire arrangement region 4. The insulating layer 9 has a thickness of, for example, about 100 to 350 nm and is a film mainly composed of silicon nitride (SiN). In the thermal method, in order to suppress power consumption, it is required to efficiently transmit the energy for discharging the liquid to the liquid. For this purpose, it is preferable to form the insulating layer 9 to be thin.

[0031] The conductive layer 10 is an anti-cavitation layer formed on the insulating layer 9 so as to cover the heating resistance element 2. The conductive layer 10 has a thickness of, for example, about 100 to 300 nm and is a film mainly composed of tantalum (Ta), iridium (Ir), or the like. In the present embodiment, the conductive layer 10 is arranged in a strip shape.

[0032] Hereinafter, a plurality of configuration examples of the element substrate 1 in the recording apparatus 30 and the recording head 32 configured as described above will be described. First, the configurations of Comparative Example 1 and Comparative Example 2 will be described, and then the configurations of Example 1, Example 2, and Example 3, which are examples of the present invention, will be described.

[0033] <Comparative Example 1> First, the configuration of the element substrate 1 according to Comparative Example 1 will be described. FIGS. 4(a) to 4(d) are diagrams showing the configuration of the element substrate 1 according to Comparative Example 1. FIG. 4(a) is a diagram showing the periphery of one heating resistance element 2 in Comparative Example 1. FIG. 4(b) is a cross-sectional view taken along line A-A in FIG. 4(a), which is a cross-sectional view seen in a cross-section parallel to the first direction D1. FIG. 4(c) is a cross-sectional view taken along line B-B in FIG. 4(a), which is a cross-sectional view seen in a cross-section parallel to the second direction D2. FIG. 4(d) is an explanatory diagram of the current distribution of the heating resistance element 2.

[0034] In Comparative Example 1, the plug 8 as a connection member is in a hole shape, and nine plugs are provided at each of the first end portion and the second end portion of one heating resistance element 2 in the first direction D1. Each plug 8 is independent of each other. Therefore, there are nine connection portions between the plug 8 and the heating resistance element 2 at each of the first end portion and the second end portion of the heating resistance element 2, and there are nine connection portions between the plug 8 and the wiring layer 7. Further, the plug 8 is formed to extend in substantially the same shape in the stacking direction, and the area of the connection portion of the plug 8 with the heating resistance element 2 is the same as the area of the connection portion with the wiring layer 7. Here, the area of the connection portion of the plug 8 refers to the area of the portion where the plug 8 is connected to other members, and in this example, it refers to the area of the portion where the plug 8 is connected to the heating resistance element 2 or the wiring layer 7 when the element substrate 1 is viewed in a plan view. For this reason, as shown in FIG. 4(d), a region where the current distribution of the heating resistance element 2 becomes sparse is generated between each plug - plug in the plug arrangement area where there are nine plugs on each side, and the heat energy generation efficiency decreases.

[0035] On the other hand, in the configuration of Comparative Example 1, each plug 8 is independent of each other, and current concentrates on each plug 8. Therefore, when the heating resistance element 2 accidentally fails and an excessive current flows through the heating resistance element 2, the plug 8 blows off. At that time, since the surrounding film including the film also melts and disappears, it functions as a fuse to avoid applying a potential to other films such as the conductive layer 10. If the plug 8 functions as a fuse, it is possible to prevent the spread of a failure to other heating resistance elements 2 when the heating resistance element 2 accidentally fails.

[0036] <Comparative Example 2> Next, the configuration of the element substrate 1 according to Comparative Example 2 will be described. FIGS. 5(a) to 5(d) are diagrams showing the configuration of the element substrate 1 according to Comparative Example 2. FIG. 5(a) is a diagram showing the periphery of one heat-generating resistance element 2 in Comparative Example 2. FIG. 5(b) is a cross-sectional view taken along line A-A of FIG. 5(a) and is a cross-sectional view as seen in a cross-section parallel to the first direction D1. FIG. 5(c) is a cross-sectional view taken along line B-B of FIG. 5(a) and is a cross-sectional view as seen in a cross-section parallel to the second direction D2. FIG. 5(d) is an explanatory diagram of the current distribution of the heat-generating resistance element 2.

[0037] In Comparative Example 2, the plug 8, which is a connection member, is slit-shaped and is provided one by one at each of the first end portion and the second end portion of one heat-generating resistance element 2 in the first direction D1. Therefore, at each of the first end portion and the second end portion of the heat-generating resistance element 2, there is one connection portion between the plug 8 and the heat-generating resistance element 2, and there is one connection portion between the plug 8 and the wiring layer 7. For this reason, according to the configuration of Comparative Example 2, as compared with the configuration of Comparative Example 1, a region where the current distribution of the heat-generating resistance element 2 becomes sparse does not occur, and the current distribution as shown in FIG. 5(d) is obtained, so the heat energy generation efficiency is high.

[0038] On the other hand, in the configuration of Comparative Example 2, since both the connection portion between the plug 8 and the wiring layer 7 and the connection portion between the plug 8 and the heat-generating resistance element 2 are formed thick, the plug 8 is difficult to be blown off, and the surrounding film is likely to remain incomplete, so the possibility of being electrically connected to other films such as the conductive layer 10 is increased. For example, if the dissolved plug 8 is electrically connected to the conductive layer 10, an unnecessary potential is applied to the conductive layer 10, which may cause a failure of other heat-generating resistance elements 2. Therefore, in Comparative Example 2, the functionality of the plug 8 as a fuse is low.

[0039] <Example 1> Next, the configuration of the element substrate 1 according to Example 1 which is an example of the present invention will be described. FIGS. 6(a) to 6(c) are diagrams showing the configuration of the element substrate 1 according to Example 1. FIG. 6(a) is a diagram showing the periphery of one heating resistance element 2 in Example 1. FIG. 6(b) is a cross-sectional view taken along line A-A in FIG. 6(a), and is a cross-sectional view seen in a cross-section parallel to the first direction D1. FIG. 6(c) is a cross-sectional view taken along line B-B in FIG. 6(a), and is a cross-sectional view seen in a cross-section parallel to the second direction D2.

[0040] In FIGS. 6(a) to 6(c), a first connection portion 8At which is a connection portion of the plug 8A on the first end side with the heating resistance element 2 and a second connection portion 8Ab which is a connection portion with the wiring layer 7 are shown. Similarly, in FIGS. 6(a) to 6(c), a first connection portion 8Bt which is a connection portion of the plug 8B on the second end side with the heating resistance element 2 and a second connection portion 8Bb which is a connection portion with the wiring layer 7 are shown. In FIG. 6(a), the first connection portions 8At and 8Bt and the second connection portions 8Ab and 8Bb are each shown by dotted lines. Hereinafter, the configuration of the plug 8 will be described by focusing on the first connection portion 8At and the second connection portion 8Ab. Since the first connection portion 8Bt and the second connection portion 8Bb are configured in the same manner as the first connection portion 8At and the second connection portion 8Ab, detailed description thereof will be omitted.

[0041] In Example 1, one plug 8 is provided at each of the first end and the second end of the heating resistance element 2 in the first direction D1. The plug 8 on the first end side of the heating resistance element 2 in the first direction D1 has one first connection portion 8At for connecting to the heating resistance element 2 and nine second connection portions 8Ab for connecting to the wiring layer 7. Similarly, the plug 8 on the second end side of the heating resistance element 2 in the first direction D1 has one first connection portion 8Bt for connecting to the heating resistance element 2 and nine second connection portions 8Bb for connecting to the wiring layer 7. That is, the number of the second connection portions 8Ab of the plug 8 provided at the first end of the heating resistance element 2 is larger than the number of the first connection portions 8At.

[0042] 6(a), the second connection portions 8Ab are formed so that their entire areas overlap with the first connection portions 8At in the stacking direction. In the first embodiment, when viewed in the stacking direction, the area of ​​the first connection portion 8At is larger than the sum of the areas of the second connection portions 8Ab. The second connection portions 8Ab are disposed at equal intervals in the second direction D2.

[0043] The plugs 8 in Comparative Examples 1 and 2 extended from the wiring layer 7 to the heating resistor element 2 in substantially the same shape. On the other hand, as shown in FIGS. 6(b) and 6(c), the plug 8 in Example 1 was The plug 8 has a tapered shape in which the cross-sectional area gradually increases from the second connection portion 8Ab toward the heating resistance element 2. The plug 8 is formed integrally in the vicinity of the heating resistance element 2. That is, the multiple second connection portions 8Ab connect to each other as they approach the heating resistance element 2 to form one first connection portion 8At. In other words, the tip portion of the plug 8 on the wiring layer 7 side branches (separates) and extends, and is connected to the wiring layer 7 by the multiple second connection portions 8Ab.

[0044] In the configuration of Example 1, the multiple second connection parts 8Ab in contact with the wiring layer 7 of the plug 8 are branched from each other and are formed so that the diameter and contact area are small. Therefore, when an excessive current flows due to an accidental failure, the second connection parts 8Ab or their vicinity are blown away as the starting point, so that the plug 8 functions as a fuse as in Comparative Example 1. In addition, the first connection parts 8At in contact with the heating resistor element 2 of the plug 8 are integrally formed so that the contact area with the heating resistor element 2 is large, so that the current path flowing through the heating resistor element 2 is the same as in Comparative Example 2, and the energy generation efficiency can be improved compared to Comparative Example 1. Furthermore, according to the configuration of Example 1, it is possible to obtain high thermal energy generation efficiency while suppressing the occurrence of failures in the element substrate 1 and maintaining the reliability of the element substrate 1 at a high level.

[0045] <Example 2> Next, the configuration of the element substrate 1 according to Example 2 which is an example of the present invention will be described. FIGS. 7(a) to 7(c) are diagrams showing the configuration of the element substrate 1 according to Example 2. FIG. 7(a) is a diagram showing the periphery of one heat generating resistance element 2 in Example 2. FIG. 7(b) is a cross-sectional view taken along line A-A of FIG. 7(a) and viewed in a cross-section parallel to the first direction D1. FIG. 7(c) is a cross-sectional view taken along line B-B of FIG. 7(a) and viewed in a cross-section parallel to the second direction D2. In FIG. 7(a), the first connection portions 8At and 8Bt and the second connection portions 8Ab and 8Bb are each illustrated by dotted lines. Hereinafter, the configuration of the plug 8 will be described by focusing on the first connection portion 8At and the second connection portion 8Ab. Since the first connection portion 8Bt and the second connection portion 8Bb are configured in the same manner as the first connection portion 8At and the second connection portion 8Ab, detailed description thereof will be omitted.

[0046] In Example 2, three plugs 8 are provided side by side in the second direction D2 at the first end portion and the second end portion of the heat generating resistance element 2 in the first direction D1. The tip portions of the plug 8 on one end side and the other end side in the second direction D2 branch and extend, and have one first connection portion 8At for connecting to the heat generating resistance element 2 and four second connection portions 8Ab for connecting to the wiring layer 7. On the other hand, the plug 8 in the center in the second direction D2 does not have a branched portion, has one first connection portion 8At for connecting to the heat generating resistance element 2, and has one second connection portion 8Ab for connecting to the wiring layer 7. That is, at the first end portion of the heat generating resistance element 2 in the first direction D1, three first connection portions 8At between the plug 8 and the heat generating resistance element 2 and nine second connection portions 8Ab between the plug 8 and the wiring layer 7 are formed. Similarly, at the second end portion of the heat generating resistance element 2 in the first direction D1, three first connection portions 8Bt between the plug 8 and the heat generating resistance element 2 and nine second connection portions 8Bb between the plug 8 and the wiring layer 7 are formed. That is, the total number of the second connection portions 8Ab of the three plugs 8 provided at the first end portion of the heat generating resistance element 2 is larger than the total number of the first connection portions 8At.

[0047] As shown in Fig. 7(a), the three first connection parts 8At are arranged side by side in the second direction D2, and the nine second connection parts 8Ab are also arranged side by side in the second direction D2. In the second embodiment, the arrangement pitch of the plurality of second connection parts 8Ab in the second direction D2 is not equally spaced. Only the second connection part 8Ab at the center in the second direction D2 has a larger interval from the other second connection parts 8Ab, and the plurality of second connection parts 8Ab are arranged accordingly.

[0048] In the plug 8 on one end side in the second direction D2, the four second connection parts 8Ab are formed such that their entire areas overlap with the first connection part 8At in the stacking direction. Similarly, in the plug 8 on the other end side in the second direction D2, the four second connection parts 8Ab are formed such that their entire areas overlap with the first connection part 8At in the stacking direction. In each of the plugs 8 on one end side and the other end side in the second direction D2, when viewed in the stacking direction, the area of the first connection part 8At is larger than the sum of the areas of the four second connection parts 8Ab. Also, in the single plug 8 at the center in the second direction D2, the second connection part 8Ab is formed such that its entire area overlaps with the first connection part 8At in the stacking direction. And in the single plug 8 at the center, when viewed in the stacking direction, the area of the first connection part 8At is larger than the area of the second connection part 8Ab. That is, the sum of the areas of the first connection parts 8At of each of the plurality of plugs 8 arranged side by side at the first end of the heating resistance element 2 is larger than the sum of the areas of the second connection parts 8Ab.

[0049] As shown in FIGS. 7(b) and 7(c), the plug 8 of Example 2 is formed to extend in a tapered shape while gradually thickening from the second connection portion 8Ab on the wiring layer 7 side toward the first connection portion 8At on the heating resistance element 2 side. Among the second connection portions 8Ab, the four second connection portions 8Ab on both end sides in the second direction D2 are connected to each other as they approach the heating resistance element 2, and each forms one first connection portion 8At. On the other hand, among the second connection portions 8Ab, one second connection portion 8Ab on the central side in the second direction D2 extends to one first connection portion 8At without being connected to the other second connection portions 8Ab. In other words, two of the three first connection portions 8At are branched into four second connection portions 8Ab and connected to the wiring layer 7, and one is connected to the wiring layer 7 without branching.

[0050] In the configuration of Example 2, compared with Example 1, the central second connection portion 8Ab is arranged away from the other second connection portions 8Ab. And the plug 8 having the central second connection portion 8Ab is separated from the other plugs 8 and independent. Therefore, in the event of an accidental failure of the heating resistance element 2, current can be concentrated on the central plug 8, so the central plug 8 is more likely to be blown off and functions as a fuse that is more likely to be a starting point. That is, according to the configuration of Example 2, high heat energy generation efficiency can be obtained, and the reliability of the element substrate 1 can be further improved compared with the configuration of Example 1.

[0051] <Example 3> Next, the configuration of the element substrate 1 according to Example 3, which is an example of the present invention, will be described. FIGS. 8(a) to 8(c) are diagrams showing the configuration of the element substrate 1 according to Example 3. FIG. 8(a) is a diagram showing the periphery of one heat-generating resistance element 2 in Example 3. FIG. 8(b) is a cross-sectional view taken along line A-A in FIG. 8(a), showing a cross-section parallel to the first direction D1. FIG. 8(c) is a cross-sectional view taken along line B-B in FIG. 8(a), showing a cross-section parallel to the second direction D2. In FIG. 8(a), the first connection portions 8At and 8Bt and the second connection portions 8Ab and 8Bb are each shown by dotted lines. Hereinafter, the configuration of the plug 8 will be described by focusing on the first connection portion 8At and the second connection portion 8Ab. Since the first connection portion 8Bt and the second connection portion 8Bb are configured in the same manner as the first connection portion 8At and the second connection portion 8Ab, detailed description thereof will be omitted.

[0052] In Example 3, seven plugs 8 are provided side by side in the second direction D2 at the first end portion and the second end portion of the heat-generating resistance element 2 in the first direction D1. The tip portions of the plugs 8 on one end side and the other end side in the second direction D2 branch and extend, and have one first connection portion 8At connected to the heat-generating resistance element 2 and two second connection portions 8Ab connected to the wiring layer 7. On the other hand, the five plugs 8 on the central side in the second direction D2 do not have a branched portion, have one first connection portion 8At connected to the heat-generating resistance element 2, and have one second connection portion 8Ab connected to the wiring layer 7. That is, at the first end portion of the heat-generating resistance element 2 in the first direction D1, seven first connection portions 8At between the plugs 8 and the heat-generating resistance element 2 and nine second connection portions 8Ab between the plugs 8 and the wiring layer 7 are formed. Similarly, at the second end portion of the heat-generating resistance element 2 in the first direction D1, seven first connection portions 8Bt between the plugs 8 and the heat-generating resistance element 2 and nine second connection portions 8Bb between the plugs 8 and the wiring layer 7 are formed. That is, the total number of the second connection portions 8Ab of the three plugs 8 provided at the first end portion of the heat-generating resistance element 2 is larger than the total number of the first connection portions 8At.

[0053] As shown in FIG. 8(a), the seven first connection portions 8At are arranged side by side in the second direction D2, and the nine second connection portions 8Ab are also arranged side by side in the second direction D2. In the third embodiment, the arrangement pitch of the plurality of second connection portions 8Ab in the second direction D2 is not equally spaced. The plurality of second connection portions 8Ab are arranged such that the interval between the first and second second connection portions 8Ab arranged from one end in the second direction D2 and the interval between the eighth and ninth second connection portions 8Ab are smaller than the intervals between the other second connection portions 8Ab.

[0054] In the plug 8 on one end side in the second direction D2, the two second connection portions 8Ab are formed such that their entire regions overlap with the first connection portion 8At in the stacking direction. Similarly, in the plug 8 on the other end side in the second direction D2, the two second connection portions 8Ab are formed such that their entire regions overlap with the first connection portion 8At in the stacking direction. In each of the plugs 8 on one end side and the other end side in the second direction D2, when viewed in the stacking direction, the area of the first connection portion 8At is larger than the sum of the areas of the two second connection portions 8Ab. Also, in each of the five plugs 8 on the central side in the second direction D2, the second connection portion 8Ab is formed such that its entire region overlaps with the first connection portion 8At in the stacking direction. And in each of the plugs 8 on the central side, when viewed in the stacking direction, the area of the first connection portion 8At is larger than the area of the second connection portion 8Ab.

[0055] As shown in FIGS. 8(b) and 8(c), the plug 8 of the third embodiment is formed to extend in a tapered shape while gradually becoming thicker from the second connection portion 8Ab on the wiring layer 7 side toward the first connection portion 8At on the heat generating resistor element 2 side. And among the second connection portions 8Ab, the two second connection portions 8Ab on both end sides in the second direction D2 are connected to each other as they approach the heat generating resistor element 2, and each forms one first connection portion 8At. On the other hand, among the second connection portions 8Ab, the five second connection portions 8Ab on the central side in the second direction D2 are not connected to the other second connection portions 8Ab and extend to different first connection portions 8At respectively. In other words, two of the seven first connection portions 8At are branched to two second connection portions 8Ab and connected to the wiring layer 7, and five are connected to the wiring layer 7 without branching.

[0056] In the configuration of Example 3, compared with the four second connection portions 8Ab provided on both end sides in the second direction D2, the other five second connection portions 8Ab are arranged apart from each other. And the plug 8 having the five central second connection portions 8Ab arranged apart from each other is separated from the other plugs 8 and is independent. Therefore, when an accidental failure occurs in the heating resistance element 2, the five central plugs 8 are more likely to be blown off and function as fuses that are likely to be the starting points. That is, according to the configuration of Example 3, high heat energy generation efficiency can be obtained, and the number of plugs 8 functioning as fuses can be increased as compared with the configuration of Example 2, so that the reliability of the element substrate 1 can be further enhanced.

[0057] <Plug manufacturing method> Next, a method for manufacturing the plug 8 according to the above-described embodiment will be described. FIGS. 9(a) and 9(b) are explanatory views of the method for manufacturing the plug 8. FIG. 9(a) shows a case where a plurality of second connection portions 8b are not connected, and FIG. 9(b) shows a state where a plurality of second connection portions 8b are connected to form a common first connection portion 8t. In FIGS. 9(a) and 9(b), for simplicity, illustration of some layers such as the intermediate layer 6 is omitted. Note that the manufacturing method shown below is merely an example and is not limited thereto. Hereinafter, the first connection portion 8At and the first connection portion 8Bt will be collectively referred to as the first connection portion 8t, and the second connection portion 8Ab and the second connection portion 8Bb will be collectively referred to as the second connection portion 8b for description.

[0058] Let the distance between the wiring layer 7 and the heating resistance element 2 in the stacking direction be d, the distance (space) in the second direction D2 between the second connection portions 8b of adjacent plugs 8 be s, and the inclination angle (plug angle) of the plug 8 be θ. Note that the inclination angle of the plug 8 is the angle formed by the upper surface of the wiring layer 7 (connection surface with the plug 8) when the element substrate 1 is viewed in the first direction D1 and the side portion of the plug 8 (portion extending from the first connection portion 8t to the second connection portion 8b). That is, it is the angle formed by the upper surface of the wiring layer 7 (connection surface with the plug 8) when the element substrate 1 is viewed in the first direction D1 and the side portion of the plug 8 (portion extending from the first connection portion 8t to the second connection portion 8b).

[0059] When the plurality of plugs 8 are not connected to each other on the side of the heating resistance element 2 and independent plugs 8 are formed, as shown in Fig. 9(a), the plug angle θ satisfies the relationship of tanθ > d / (s / 2). On the other hand, when the plugs 8 are connected on the side of the heating resistance element 2 and plugs 8 having a plurality of second connection portions 8b are formed, as shown in Fig. 9(b), the plug angle θ satisfies the relationship of tanθ < d / (s / 2). Since the shape of the plug 8 is determined by the shape of the hole formed in the intermediate layer 6 by etching or the like, by adjusting the etching conditions or the like, the plug 8 can be formed in a tapered shape and connected on the side of the heating resistance element 2 as necessary.

[0060] As described above, according to the configuration of the foregoing embodiment, it is possible to provide a highly reliable liquid discharge head substrate that enhances the thermal energy generation efficiency of the heating resistor. It should be noted that the present invention is not limited to the configuration of the foregoing embodiment, and various changes and modifications are possible without departing from the spirit and scope of the invention. For example, in the second embodiment and the third embodiment, the plug 8 disposed on the central side in the second direction D2 is configured to function as a fuse, but the plug 8 disposed on the end side in the second direction D2 may be configured to function as a fuse. Further, for example, in the configuration of the second embodiment, the first connection portions 8At of the three plugs 8 provided on the first end side in the first direction D1 of the element substrate 1 may be connected to each other to form one plug 8.

[0061] The disclosure of the present embodiment includes the following configurations. (Configuration 1) An element substrate for a liquid discharge head that discharges a liquid, A heating resistance element that generates energy for discharging the liquid by heating, A wiring layer for supplying power to the heating resistance element, A connection member having a first connection portion connected to the heating resistance element and a second connection portion connected to the wiring layer, and electrically connecting the heating resistance element and the wiring layer, Comprising, The connecting member is characterized in that the tip on the wiring layer side branches and extends, and is connected to the wiring layer at a plurality of the second connection parts. An element substrate. (Configuration 2) The number of the second connection parts of the connecting member is larger than the number of the first connection parts. The element substrate according to Configuration 1. (Configuration 3) The connecting member has a tapered shape in which the cross-sectional area gradually increases from each of the plurality of the second connection parts toward the heating resistance element. The element substrate according to Configuration 1 or 2. (Configuration 4) The area of the first connection part is larger than the area of the second connection part. The element substrate according to any one of Configurations 1 to 3. (Configuration 5) The area of the first connection part is larger than the sum of the areas of the plurality of the second connection parts. The element substrate according to any one of Configurations 1 to 4. (Configuration 6) The second connection part is arranged at a position where the entire area overlaps with the first connection part in a plan view of the element substrate. The element substrate according to any one of Configurations 1 to 5. (Configuration 7) The connecting member is provided at a first end part and a second end part in a first direction of the heating resistance element in a plan view of the element substrate, respectively, at each of the first end part and the second end part, a plurality of the second connection parts are arranged side by side in a second direction intersecting the first direction. The element substrate according to any one of Configurations 1 to 6. (Configuration 8) At each of the first end part and the second end part, a plurality of the connecting members are provided side by side in the second direction. The element substrate according to Configuration 7. (Configuration 9) The total number of the second connection parts of the plurality of the connecting members provided side by side in the second direction is larger than the total number of the first connection parts. The element substrate according to Configuration 8. (Configuration 10) In the plurality of the connection members provided side by side in the second direction, the sum of the areas of the respective first connection portions is larger than the sum of the areas of the respective second connection portions, the element substrate according to Configuration 8. (Configuration 11) The element substrate is a laminate in which a plurality of functional layers are laminated in a stacking direction, With the distance in the stacking direction between the heating resistance element and the wiring layer being d, the distance between the second connection portions adjacent to each other in the second direction being s, and the angle formed between the connection surface of the wiring layer with the connection member and the side portion extending from the first connection portion to the second connection portion of the connection member being θ, the connection member satisfies tanθ < d / (s / 2), the element substrate according to any one of Configurations 8 to 10. (Configuration 12) The connection member includes a film formed of tungsten, the element substrate according to any one of Configurations 1 to 11. (Configuration 13) The heating resistance element includes a tantalum silicon nitride material, the element substrate according to any one of Configurations 1 to 12. (Configuration 14) The element substrate is a laminate composed of a plurality of functional layers, a substrate, an intermediate layer laminated on the substrate, having the wiring layer formed therein and the heating resistance element formed on the upper surface, an insulating layer covering the heating resistance element, a conductive layer laminated on the insulating layer, and comprising, the element substrate according to any one of Configurations 1 to 13. (Configuration 15) The conductive layer includes iridium, the element substrate according to Configuration 14. (Configuration 16) An element substrate for a liquid ejection head that ejects a liquid, a heating resistance element that generates energy for ejecting the liquid by heating, a wiring layer for supplying power to the heating resistance element, A connecting member having a first connection portion connected to the heating resistance element and a second connection portion connected to the wiring layer, for electrically connecting the heating resistance element and the wiring layer, comprising: An element substrate, wherein the area of the first connection portion is larger than the area of the second connection portion. (Configuration 17) The connecting member has a tip portion on the wiring layer side separated therefrom, and is connected to the wiring layer by a plurality of the second connection portions, The element substrate according to Configuration 16, wherein the area of the first connection portion is larger than the sum of the areas of the plurality of second connection portions. (Configuration 18) In a plan view of the element substrate, the connecting member is provided at a first end portion and a second end portion in a first direction of the heating resistance element, respectively, The element substrate according to Configuration 16 or 17, wherein at each of the first end portion and the second end portion, a plurality of the connecting members are arranged side by side in a second direction intersecting the first direction. (Configuration 19) The element substrate is a laminate in which a plurality of functional layers are laminated in a stacking direction, Let the distance in the stacking direction between the heating resistance element and the wiring layer be d, the distance between the second connection portions adjacent to each other in the second direction be s, and the angle formed between the connection surface of the wiring layer with the connecting member and the side portion of the connecting member extending from the first connection portion to the second connection portion be θ. The connecting member satisfies tanθ < d / (s / 2). The element substrate according to Configuration 18. (Configuration 20) A liquid ejection head, comprising the element substrate according to any one of Configurations 1 to 19.

Explanation of Reference Numerals

[0062] 1... Element substrate, 2... Heating resistance element, 7... Wiring layer, 8... Plug (connecting member), 8At (8Bt)... First connection portion, 8Ab (8Bb)... Second connection portion, 32... Recording head (liquid ejection head)​

Claims

1. An element substrate for a liquid ejection head that ejects a liquid, comprising: a heating resistor element that generates energy for ejecting the liquid by heating; a wiring layer for supplying power to the heating resistor element; a first connection portion connected to the heating resistor element and a second connection portion connected to the wiring layer, and a connection member that electrically connects the heating resistor element and the wiring layer; wherein the connection member has a tip portion on the wiring layer side that branches and extends, and is connected to the wiring layer at a plurality of the second connection portions.

2. The element substrate according to claim 1, wherein the number of the second connection portions of the connection member is larger than the number of the first connection portions.

3. The element substrate according to claim 1, wherein the connection member has a tapered shape in which the cross-sectional area gradually increases as it approaches the heating resistor element from each of the plurality of second connection portions.

4. The element substrate according to claim 1, wherein the area of the first connection portion is larger than the area of the second connection portion.

5. The element substrate according to claim 1, wherein the area of the first connection portion is larger than the sum of the areas of the plurality of second connection portions.

6. The element substrate according to claim 1, wherein the second connection portion is disposed at a position where the entire area thereof overlaps with the first connection portion in a plan view of the element substrate.

7. In a plan view of the element substrate, the connection member is provided at a first end portion and a second end portion in a first direction of the heating resistor element, respectively, and at each of the first end portion and the second end portion, the plurality of second connection portions are arranged side by side in a second direction intersecting the first direction.

8. The element substrate according to claim 7, wherein at each of the first end portion and the second end portion, a plurality of the connection members are provided side by side in the second direction.

9. The element substrate according to claim 8, wherein the total number of the second connection portions of the plurality of connection members provided side by side in the second direction is larger than the total number of the first connection portions.

10. The element substrate according to claim 8, wherein in the plurality of connection members provided side by side in the second direction, the sum of the areas of the respective first connection portions is larger than the sum of the areas of the respective second connection portions.

11. The element substrate is a laminate in which a plurality of functional layers are laminated in the stacking direction. With the distance in the stacking direction between the heating resistance element and the wiring layer being d, the distance between the second connection portions adjacent to each other in the second direction being s, and the angle formed between the connection surface of the wiring layer with the connection member and the side portion of the connection member extending from the first connection portion to the second connection portion being θ, the connection member satisfies tan θ < d / (s / 2), and the element substrate according to claim 8 is characterized thereby.

12. The element substrate according to claim 1, wherein the connection member includes a film formed of tungsten.

13. The element substrate according to claim 1, wherein the heating resistance element includes a tantalum silicon nitride material.

14. The element substrate is a laminate composed of a plurality of functional layers. A base body; An intermediate layer laminated on the base body, with the wiring layer formed inside and the heating resistance element formed on the upper surface; An insulating layer covering the heating resistance element; A conductive layer laminated on the insulating layer; The element substrate according to claim 1, characterized by comprising the above.

15. The element substrate according to claim 14, wherein the conductive layer contains iridium.

16. An element substrate for a liquid ejection head that ejects a liquid, A heating resistance element that generates energy for ejecting the liquid by heating; A wiring layer for supplying power to the heating resistance element; A connection member having a first connection portion connected to the heating resistance element and a second connection portion connected to the wiring layer, and electrically connecting the heating resistance element and the wiring layer; Comprising; The area of the first connection portion is larger than the area of the second connection portion, and the element substrate is characterized thereby.

17. The tip portion on the wiring layer side of the connection member is separated, and the connection member is connected to the wiring layer at a plurality of the second connection portions. The area of the first connection portion is larger than the sum of the areas of the plurality of the second connection portions, and the element substrate according to claim 16 is characterized thereby.

18. In a plan view of the element substrate, the connection member is provided at a first end portion and a second end portion of the heating resistance element in a first direction, respectively. At each of the first end portion and the second end portion, a plurality of the connection members are provided side by side in a second direction intersecting the first direction, and the element substrate according to claim 16 is characterized thereby.

19. The element substrate is a laminate formed by laminating a plurality of functional layers in the stacking direction. With the distance in the stacking direction between the heating resistance element and the wiring layer being d, the distance between the second connection portions adjacent to each other in the second direction being s, and the angle formed between the connection surface of the wiring layer with the connection member and the side portion of the connection member extending from the first connection portion to the second connection portion being θ, the connection member satisfies tan θ < d / (s / 2), and the element substrate according to claim 18 is characterized by this.

20. A liquid ejection head comprising the element substrate according to any one of claims 1 to 19.

Images