METHOD FOR MANUFACTURING LIQUID DISCHARGE HEAD, LIQUID DISCHARGE HEAD, AND METHOD FOR MANUFACTURING LIQUID DISCHARGE HEAD SUBSTRATE

Abstract

There is provided a method for manufacturing a liquid discharge head including a liquid discharge head substrate and a flow path forming member, the liquid discharge head substrate having a base, a pressure generation portion provided at a front surface of the base to generate pressure for discharging a liquid, and a supply port for supplying the liquid to the pressure generation portion, and the flow path forming member forming a flow path for feeding the liquid supplied from the supply port to the pressure generation portion. The method includes removing a sacrificial layer by etching the base from a back surface of the base, in a state in which an end covering portion of a cover layer for covering the sacrificial layer is covered with the resin layer. The method suppresses formation of a crack in the end covering portion that covers the end portion of the sacrificial layer.

Claims

1. A liquid discharge head comprising: a liquid discharge head substrate having a base, a pressure generation portion provided at a side of a front surface of the base to generate pressure for discharging a liquid, a cover layer provided at the side of the front surface of the base, and a supply port passing through the base and the cover layer to supply the liquid to the pressure generation portion; a flow path forming member provided at the side of the front surface of the base to form a flow path for feeding the liquid supplied from the supply port to the pressure generation portion; and a resin layer provided on a front surface of the cover layer facing the flow path forming member and provided over an opening edge portion of the supply port provided on the front surface of the cover layer, wherein the resin layer includes a part contacting the front surface of the cover layer, and a step portion located at inside of the supply port as viewed from a direction orthogonal to the front surface of the base and the step portion includes a step coming closer to the flow path forming member than the part contacting the front surface of the cover layer.

2. The liquid discharge head according to claim 1, further comprising an intermediate layer formed between the liquid discharge head substrate and the flow path forming member, using a same material as a material of the resin layer.

3. The liquid discharge head according to claim 2, wherein the resin layer and the intermediate layer are connected.

4. The liquid discharge head according to claim 3, wherein the liquid discharge head substrate includes the pressure generation portions adjacent to each other, the liquid discharge head comprises the pressure chambers each including the pressure generation portion, the flow paths communicating with the respective pressure chambers, and a common liquid chamber allowing the flow paths and the supply port to communicate with each other, the intermediate layer is not provided in an area of a surface of the liquid discharge head substrate facing the flow path forming member across the pressure chambers, the flow paths, and a part of the common liquid chamber, and the intermediate layer is connected to the resin layer through the common liquid chamber from between a partition of the flow path forming member to separate the pressure chambers adjacent to each other and the flow paths adjacent to each other and the liquid discharge head substrate.

5. The liquid discharge head according to claim 1, wherein the resin layer is made of polyether amide.

6. The liquid discharge head according to claim 1, wherein the resin layer is thicker than the cover layer.

7. The liquid discharge head according to claim 1, wherein an opening, which has an opening area smaller than an opening area of the supply port of the cover layer viewed from the direction, is provided on the resin layer.

8. The liquid discharge head according to claim 1, wherein the cover layer includes a silicon compound.

9. The liquid discharge head according to claim 1, wherein the liquid discharge head substrate has a pressure generation element to form the pressure generation portion, and the cover layer includes a layer for covering the pressure generation element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIGS. 1A, 1B, and 1C are diagrams illustrating a liquid discharge head according to a first exemplary embodiment.

[0014] FIGS. 2A to 2D are diagrams illustrating a method for manufacturing the liquid discharge head.

[0015] FIGS. 3A to 3D are diagrams illustrating the method for manufacturing the liquid discharge head.

[0016] FIGS. 4A to 4D are diagrams illustrating the method for manufacturing the liquid discharge head.

[0017] FIGS. 5A to 5D are diagrams illustrating the method for manufacturing the liquid discharge head.

[0018] FIGS. 6A to 6D are diagrams illustrating the method for manufacturing the liquid discharge head.

[0019] FIGS. 7A to 7D are diagrams illustrating the method for manufacturing the liquid discharge head.

[0020] FIGS. 8A to 8D are diagrams illustrating the method for manufacturing the liquid discharge head.

[0021] FIGS. 9A and 9B are diagrams illustrating a liquid discharge head according to a second exemplary embodiment.

[0022] FIGS. 10A and 10B are diagrams illustrating a liquid discharge head according to a third exemplary embodiment.

[0023] FIG. 11 is a perspective diagram illustrating a liquid discharge apparatus.

[0024] FIG. 12 is a perspective diagram illustrating a liquid discharge head unit.

[0025] FIG. 13 is a perspective diagram illustrating a liquid discharge head.

DESCRIPTION OF THE EMBODIMENTS

[0026] FIG. 11 is a perspective diagram schematically illustrating a liquid discharge apparatus 1 (an inkjet recording apparatus) on which a liquid discharge head unit 2 is mounted, according to an exemplary embodiment. FIG. 12 is a perspective diagram illustrating an example of the liquid discharge head unit 2 to be mounted on the liquid discharge apparatus 1. The liquid discharge head unit 2 has a head housing 15, an electrical connection printed board 16, a flexible board 13, and a liquid discharge head 14. The liquid discharge head unit 2 is electrically connected to a main body of the liquid discharge apparatus 1 via the electrical connection printed board 16. The electrical connection printed board 16 and the liquid discharge head 14 are electrically connected via the flexible board 13. The head housing 15 contains a tank (not illustrated) for containing a liquid such as ink. The head housing 15 guides the liquid from the tank into the liquid discharge head 14.

[0027] FIG. 13 is a perspective diagram illustrating an example of the liquid discharge head 14 (an inkjet recording head) partially cut away. The liquid discharge head 14 has a liquid discharge head substrate 10 and a flow path forming member 20. The liquid discharge head 14 has a heat application portion 12 (a pressure generation portion) and a discharge port 21. The heat application portion 12 corresponds to a heater serving as a pressure generation element formed on the liquid discharge head substrate 10. The heat application portion 12 is in contact with the liquid. The discharge port 21 is formed in the flow path forming member 20. The discharge port 21 is formed at a position which corresponds to the heat application portion 12, on a surface of the flow path forming member 20. This surface faces a record medium. One or more discharge ports 21 are arranged at a predetermined pitch to form an array. Similarly, one or more heat application portions 12 are arranged at a predetermined pitch to form an array.

[0028] The liquid discharge head substrate 10 has a supply port 11 provided to pass through the liquid discharge head substrate 10. The supply port 11 is provided to supply the liquid to the heat application portion 12. Further, a bubble generation chamber 22 serving as a pressure chamber is provided to communicate with the discharge port 21 and to surround the heat application portion 12. The bubble generation chamber 22 is formed by the flow path forming member 20. The supply port 11 has an opening edge portion 11a shaped like a rectangle and extended in a direction of the array of the bubble generation chambers 22 and the array of the discharge ports 21.

[0029] The flow path forming member 20 and the liquid discharge head substrate 10 are bonded together to form a flow path 23 and a common liquid chamber 24 (see FIGS. 1A and 1B). The flow path 23 communicates with each of the discharge ports 21. The common liquid chamber 24 retains the liquid supplied from the supply port 11, and distributes the liquid to the flow path 23. The liquid supplied through the supply port 11 is supplied to the bubble generation chamber 22 through the common liquid chamber 24 and the flow path 23.

[0030] Thermal energy generated by the heater is applied, via the heat application portion 12, to the liquid supplied into the bubble generation chamber 22. This causes film boiling, thereby generating bubbles in the bubble generation chamber 22. Bubbling pressure of these bubbles increases pressure in the bubble generation chamber 22. This applies kinetic energy to the liquid, so that a droplet is discharged from the discharge port 21. In this process, power and a drive signal are supplied from the main body of the liquid discharge apparatus 1 to the heater via a connection pad 17 provided on the liquid discharge head substrate 10, so that the heater is driven to generate the thermal energy. A dot is formed on a record medium P by discharge of a droplet from the discharge port 21 of the liquid discharge head 14 to the record medium P, so that an image is recorded on the record medium P.

[0031] A configuration of the liquid discharge head 14 according to a first exemplary embodiment will be described. FIGS. 1A to 1C are diagrams illustrating the liquid discharge head 14 according to the first exemplary embodiment. FIG. 1A is an enlarged top view of a region A illustrated in FIG. 13. FIG. 1B is a diagram illustrating only a section taken along a B-B line illustrated in FIG. 1A. FIG. 1C is an enlarged view of a part near the supply port 11 on the front surface of the liquid discharge head substrate 10 illustrated in FIG. 1B.

[0032] A silicon base is used as a base 10a of the liquid discharge head substrate 10. A heat accumulation layer 210 made of a material such as silicon oxide is formed on the front surface of the base 10a. Elements including a heater 220 made of tantalum nitride, a switching element for driving the heater 220, and a selection circuit (not illustrated) are provided on the front surface of the heat accumulation layer 210. The heater 220 is connected to a heater electrode (not illustrated). Further, a protective layer 230 for protecting the heater 220 is formed on the front surface of the heat accumulation layer 210 and the heater 220. The protective layer 230 is made of a material such as silicon nitride. The flow path forming member 20 is formed at the front surface of the liquid discharge head substrate 10, i.e., at the front surface of the protective layer 230. The flow path forming member 20 is made of, for example, an epoxy-based resin material.

[0033] Further, an intermediate layer 101 is formed between the protective layer 230 of the liquid discharge head substrate 10 and the flow path forming member 20. The intermediate layer 101 is made of a material having more strength of adhesion to (strength of bonding with) the protective layer 230 than that of the flow path forming member 20. This can suppress peeling of the flow path forming member 20 off the liquid discharge head substrate 10 (the protective layer 230). The intermediate layer 101 may be formed of a material having the above-described characteristic. Examples of this material include resin materials such as HIMAL (produced by Hitachi Chemical Co., Ltd.) and SU-8 (produced by Kayaku MicroChem Corporation).

[0034] Furthermore, a resin layer 102 is provided over the opening edge portion 11a of the supply port 11 formed on the front surface of the liquid discharge head substrate 10, as illustrated in FIG. 1A. In other words, the resin layer 102 extends above a region inside the supply port 11, when viewed from the front surface of the liquid discharge head substrate 10 (the surface, on which the flow path forming member 20 is provided, of the liquid discharge head substrate 10).

[0035] The resin layer 102 has a part contacting the front surface of the liquid discharge head substrate 10 (the front surface of the protective layer 230), and a part extending above the region inside the supply port 11 along this front surface, as illustrated in FIG. 1B. Moreover, the resin layer 102 has a step portion 103, which is closer to the flow path forming member 20 than the part contacting the front surface of the protective layer 230. The step portion 103 is formed together with an end covering portion that covers an end of a sacrificial layer 310 to be described below.

[0036] The resin layer 102 has a width of, for example, 8 m to 12 m. The resin layer 102 is provided to surround the opening edge portion 11a of the supply port 11. Specifically, the resin layer 102 has an opening having an area smaller than an opening area of the supply port 11. From the viewpoint of supplying the liquid, a width W1 of a part which is located inside the supply port 11, of the resin layer 102 is desirably about 1/30 to 1/200 of an opening width W2 of the supply port 11.

[0037] Next, a method for manufacturing the liquid discharge head 14 will be described with reference to FIGS. 2A to 2D through FIGS. 8A to 8D. FIGS. 2A, 3A, 4A, 5A, 6A, 7A, and 8A are diagrams each illustrating the region A illustrated in FIG. 13, when viewed from the front surface side of the liquid discharge head 14. The region A is partially transparent. FIGS. 2B, 3B, 4B, 5B, 6B, 7B, and 8B are diagrams each illustrating the liquid discharge head 14 when viewed from the back surface side of the liquid discharge head substrate 10. FIGS. 2C, 3C, 4C, 5C, 6C, 7C, and 8C are diagrams each illustrating only a section taken along a C-C line in the corresponding FIGS. 2A, 3A, 4A, 5A, 6A, 7A, and 8A. FIGS. 2D, 3D, 4D, 5D, 6D, 7D, and 8D are diagrams each illustrating an enlarged view of a part near the supply port 11 of the liquid discharge head substrate 10 in corresponding FIGS. 2C, 3C, 4C, 5C, 6C, 7C, and 8C.

[0038] First, as illustrated in FIGS. 2A to 2D, the sacrificial layer 310 made of, for example, aluminum is formed by sputtering, on the front surface of the base 10a made of silicon. The sacrificial layer 310 is configured to form the supply port 11 with high dimensional accuracy. The sacrificial layer 310 is provided at a position on the inner side of an opening region of the supply port 11 formed in a later process. Next, as illustrated in FIGS. 3A to 3D, the heat accumulation layer 210 (that has desirably a thickness of 0.5 m to 2 m) made of, for example, silicon oxide is formed to cover the sacrificial layer 310, by a high density plasma CVD (HDP-CVD) method. Further, the heater 220 made of, for example, tantalum nitride is formed on the front surface of the heat accumulation layer 210 by sputtering. Furthermore, the protective layer 230 (that has desirably a thickness of 0.1 m to 0.5 m) made of, for example, silicon nitride is formed on the front surface of the heat accumulation layer 210 and the heater 220, by a plasma CVD method.

[0039] A portion 211 of the heat accumulation layer 210 and a portion 231 of the protective layer 230 cover the end of the sacrificial layer 310 (FIG. 3D). Since the portion 211 and the portion 231 cover a step formed by the sacrificial layer 310, they have a film thickness less than a part formed on a flat surface of the liquid discharge head substrate 10. The heat accumulation layer 210 and the protective layer 230 each may also be referred to as a cover layer that covers the sacrificial layer 310. In addition, the portion 211 of the heat accumulation layer 210 and the portion 231 of the protective layer 230 may also be referred to as the end covering portion that covers the end of the sacrificial layer 310. The cover layer is formed of a material including a silicon compound.

[0040] Further, the intermediate layer 101 (which has desirably a thickness of 1 m to 4 m) made of a polyether-amide-based resin material is formed by spin coating on the front surface of the protective layer 230 located near the heater 220. Furthermore, the resin layer 102 is formed to provide the step portion 103 that covers the portion 211 of the heat accumulation layer 210 and the portion 231 of the protective layer 230. The intermediate layer 101 and the resin layer 102 are formed as one layer by using the same material in the same process. However, the intermediate layer 101 and the resin layer 102 may be formed using different materials. In this process, an opening 104 is desirably provided in the resin layer 102. In this way, it becomes unnecessary to add a process of forming the opening 104 through which the liquid flows from the supply port 11. Since the opening 104 is provided, the front surface of a part, which covers the sacrificial layer 310, of the protective layer 230 is exposed from the opening 104. The opening 104 has an area smaller than the opening area of the supply port 11, and smaller than the area of the sacrificial layer 310 viewed from a direction orthogonal to the front surface of the liquid discharge head substrate 10.

[0041] Next, a flow path mold member 320 made of a resist material is formed by spin coating, on the front surface of the protective layer 230, the intermediate layer 101, and the resin layer 102, as illustrated in FIGS. 4A to 4D. Further, the flow path forming member 20 made of an epoxy-based resin material, for example, is formed by spin coating, on the front surface of the protective layer 230 and the front surface of the flow path mold member 320. The flow path forming member 20 can be formed using a resist material having photosensitivity. Furthermore, the discharge port 21 is formed in the flow path forming member 20 through photolithography.

[0042] Next, a front surface protective layer 330 made of a resist material is formed by spin coating, on the front surface of the flow path forming member 20 and the flow path mold member 320, as illustrated in FIGS. 5A to 5D. Further, a supply port forming mask layer 340 made of a resist material is formed by spin coating, on the back surface of the liquid discharge head substrate 10.

[0043] Next, silicon anisotropic wet etching is performed using tetramethylammonium hydroxide (TMAH) from the back surface side of the base 10a, by using the supply port forming mask layer 340 as a mask, as illustrated in FIGS. 6A to 6D. This process forms the supply port 11 in the base 10a. The sacrificial layer 310 is immediately etched and thereby removed, when TMAH reaches the sacrificial layer 310 provided at the front surface of the liquid discharge head substrate 10. This is because an etching rate of the sacrificial layer 310 made of aluminum is faster than that of the base 10a that is a silicon base. In this process, the heat accumulation layer 210 also functions as an etching-resistant layer for stopping the progress of the etching in regard to TMAH.

[0044] Next, a portion located in the region inside the supply port 11 of the heat accumulation layer 210 is removed by wet etching using buffered hydrogen fluoride (BHF), as illustrated in FIGS. 7A to 7D. Further, a portion located in the region inside the supply port 11 of the protective layer 230 is removed by dry etching. In this way, the supply port 11 passing through the front surface and the back surface of the liquid discharge head substrate 10 is formed.

[0045] Next, the front surface protective layer 330 and the supply port forming mask layer 340 are removed by asking and rinsing, as illustrated in FIGS. 8A to 8D. Further, the flow path mold member 320 is removed by wet etching. In this way, the liquid discharge head 14 is formed.

[0046] Here, when the base 10a is etched in the process of forming the supply port 11 illustrated in FIGS. 6A to 6D, warpage may occur in the base 10a because of internal stress of, for example, the heat accumulation layer 210, the protective layer 230, and the flow path forming member 20. In the portion 211 of the heat accumulation layer 210 and the portion 231 of the protective layer 230 which cover the end of the sacrificial layer 310 formed in the process illustrated in FIGS. 3A to 3D, a film thickness is less than a part formed on a flat surface. Therefore, in a configuration in which the resin layer 102 is not provided, a crack may be formed in the portion 211 of the heat accumulation layer 210 or the portion 231 of the protective layer 230 having relatively low rigidity when the base 10a is etched from the back surface. In particular, such an issue is more likely to arise if the heat accumulation layer 210 is formed using the HDP-CVD method to miniaturize a circuit, because the portion 211 of the heat accumulation layer 210 is formed further thinner than the part formed on the flat surface.

[0047] Therefore, as described above, the base 10a is etched to form the supply port 11, in a state in which the front surface side of the portion 211 of the heat accumulation layer 210 and the portion 231 of the protective layer 230 is covered by the resin layer 102, as illustrated in FIGS. 6A to 6D. The portion 211 of the heat accumulation layer 210 and the portion 231 of the protective layer 230 each serving as the end covering portion are therefore reinforced by the resin layer 102 during the etching of the base 10a. This can suppress formation of a crack. The adhering (bonding) strength of the resin layer 102 to the protective layer 230 (the cover layer) is higher than the adhering strength of the flow path mold member 320 to the protective layer 230 (the cover layer). This can provide stronger reinforcement because the resin layer 102 is brought into tight contact with the protective layer 230, as compared with a configuration of providing the flow path mold member 320 on the front surface of the protective layer 230 with no resin layer 102. The formation of a crack can be therefore suppressed.

[0048] The resin layer 102 is desirably formed in the same process as the process of forming the intermediate layer 101 disposed between the flow path forming member 20 and the liquid discharge head substrate 10. This can suppress the formation of a crack without adding more process. Further, the heat accumulation layer 210 and the protective layer 230 can be used as an etching-resistant layer during silicon anisotropic etching, by disposing the heat accumulation layer 210 and the protective layer 230 in the region inside the supply port 11.

[0049] The resin layer 102 can be formed thicker than the cover layer such as the heat accumulation layer 210 and the protective layer 230. In this way, the end covering portion of the heat accumulation layer 210 and the protective layer 230 can be more firmly reinforced by using the resin layer 102.

[0050] As for Japanese Patent Application Laid-Open No. 2007-160624, in which the protective layer is not provided inside the opening region of the supply port, it may become difficult in a manufacturing process to implement the configuration discussed therein. This is because, in a case where the protective layer is formed of a material containing a silicon compound such as silicon nitride, it may become difficult to ensure a difference in etching rate between the protective layer and the base 10a made of silicon, and thus process control may become difficult. In contrast, the heat accumulation layer 210 and the protective layer 230 are provided inside a region that becomes the supply port 11, before the supply port 11 is formed. It is therefore possible to suppress the formation of the above-described crack in the cover layer while adopting a simple manufacturing method.

[0051] FIGS. 9A and 9B are diagrams illustrating a liquid discharge head according to a second exemplary embodiment. FIG. 9A is an enlarged top view of the region A illustrated in FIG. 13. FIG. 9B is a diagram illustrating only a section taken along a D-D line illustrated in FIG. 9A.

[0052] The second exemplary embodiment assumes a configuration in which an intermediate layer and a resin layer are formed as one layer while using the same material. Therefore, the intermediate layer and the resin layer in the first exemplary embodiment are combined and may be referred to as an intermediate layer 401. The intermediate layer 401 includes a part provided between the flow path forming member 20 and the liquid discharge head substrate 10 (the protective layer 230), a part facing the common liquid chamber 24 (a part of the intermediate layer 401), and a part extending to the region inside the supply port 11. In addition, these parts of the intermediate layer 401 are connected to each other. The intermediate layer 401 is not provided inside the bubble generation chamber 22.

[0053] The intermediate layer 401 has a step portion 402 which comes close to the flow path forming member 20 in the region inside the supply port 11. The step portion 402 reinforces the portion 211 of the heat accumulation layer 210 and the portion 231 of the protective layer 230 in a process of forming the supply port 11. It is therefore possible to suppress the formation of a crack in these parts.

[0054] The supply port 11 may be formed to be a large port because of variations in a manufacturing process. This may locate the resin layer 102 surrounding the opening edge portion 11a of the supply port 11 according to the first exemplary embodiment, in the region inside the supply port 11 of the base 10a. In this case, the resin layer 102 may be formed to be sunk to the supply port 11, if the intermediate layer 101 and the resin layer 102 are separated, i.e., not connected to each other, as in the first exemplary embodiment.

[0055] In contrast, the intermediate layer 401 has a part formed between the flow path forming member 20 and the protective layer 230, and a part located in the region inside the supply port 11 which includes the step portion 402. These parts are formed to be connected to each other. This prevents such a situation that the entire intermediate layer 401 is located in the region inside the supply port 11 even if the supply port 11 is formed as a large port. It is therefore possible to suppress sinking of the intermediate layer 401 to the supply port 11 due to variations in manufacturing the supply port 11.

[0056] FIGS. 10A and 10B are diagrams illustrating a liquid discharge head according to a third exemplary embodiment. FIG. 10A is an enlarged top view of the region A illustrated in FIG. 13. FIG. 10B is a diagram illustrating only a section taken along an E-E line illustrated in FIG. 10A.

[0057] The third exemplary embodiment assumes a configuration in which an intermediate layer and a resin layer are formed as one layer using the same material. Therefore, the intermediate layer and the resin layer in the first exemplary embodiment are combined and referred to as an intermediate layer 601. The intermediate layer 601 has a step portion 602 which comes close to the flow path forming member 20 in the region inside the supply port 11. The step portion 602 reinforces the portion 211 of the heat accumulation layer 210 and the portion 231 of the protective layer 230 in a process of forming the supply port 11. It is therefore possible to suppress the formation of a crack in these parts.

[0058] Further, as with the second exemplary embodiment, the intermediate layer 601 has a part provided between the flow path forming member 20 and the liquid discharge head substrate 10 (the protective layer 230), a part facing the common liquid chamber 24, and a part extending to the region inside the supply port 11. In addition, these parts of the intermediate layer 601 are connected to each other. It is therefore possible to suppress sinking of the intermediate layer 601 to the supply port 11 due to variations in manufacturing the supply port 11.

[0059] Here, a part of the intermediate layer 601 formed between the flow path forming member 20 and the protective layer 230 is referred to as a first part 611. Further, a part of the intermediate layer 601 including the step portion 602 and provided over the opening edge portion 11a of the supply port 11 is referred to as a second part 612. Furthermore, a part of the intermediate layer 601 provided at a position facing the common liquid chamber 24 and connecting the first part 611 and the second part 612 is referred to as a third part 613. The intermediate layer 601 is not provided in the bubble generation chamber 22 and the flow path 23.

[0060] Further, the flow path forming member 20 has a wall 25 formed between the adjacent bubble generation chambers 22, and between the adjacent flow paths 23. The first part 611 is located between the wall 25 and the liquid discharge head substrate 10. The third part 613 connects the first part 611 and the second part 612 along an extending direction of the wall 25, as illustrated in FIG. 10A. The extending direction of the wall 25 is also a direction along the front surface of the liquid discharge head substrate 10 and intersecting with the array direction of the heat application portions 12. In other words, the intermediate layer 601 is not provided in a part 24a of the common liquid chamber 24 that communicates with the flow path 23.

[0061] In this way, in addition to the configuration of the second exemplary embodiment, a configuration is adopted which does not provide the intermediate layer 601 in the part 24a that communicates with the flow path 23 of the common liquid chamber 24. This can suppress an increase in resistance to the flow from the supply port 11 to the bubble generation chamber 22. Therefore, it is possible to ensure supply of the liquid to the bubble generation chamber 22, while suppressing the sinking of the intermediate layer 601 to the supply port 11.

[0062] In order to further suppress the increase in resistance to the flow, a width W3 (a length in the array direction of the heat application portions 12) of the third part 613 is desirably shorter than each of a width W4 and a width W5 of the first part 611 located between the wall 25 and the liquid discharge head substrate 10.

[0063] While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.