Structure and its manufacturing method

Abstract

To prevent sectional reduction or blockage of a hole caused by crawling-up of an adhesive.SOLUTION: A structure 10 comprises: a first member 1 that has a first joint surface S1; a second member 2 that has a second joint surface S2; and a first adhesive B1 that bonds the first and second members 1 and 2. The first member 1 has a first hole 11 extending from the first joint surface S1. The first hole 11 has a center 12 that extends in a first direction Z, and at least one first groove 13 that extends on the side surface 12A of the center 12 in a peripheral direction. The first adhesive B1 is interposed between the first joint surface S1 and the second joint surface S2, and buries at least a part of the first groove 13. In the first direction Z, at least a part of a bottom 15 of the first groove 13 is at a position different from that of an opening 16 of the first groove 13.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a structure and a method for manufacturing the same.

Background Art

[0002] In a liquid ejection head used in an inkjet printer or the like, in order to form a liquid ejection flow path, a plurality of substrates with holes formed therein may be joined. At this time, due to the pressure bonding during joining, an excess adhesive protrudes into the holes, and a phenomenon of creeping up along the side surfaces of the holes is known. This phenomenon may cause a reduction in the cross-sectional area or blockage of the liquid flow path. Patent Document 1 discloses a liquid ejection head provided with a hole diameter expansion portion in the vicinity of the joining surface. The diameter expansion portion accommodates the creeping-up adhesive and reduces the possibility of reduction in the cross-sectional area or blockage of the liquid flow path.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the configuration disclosed in Patent Document 1, since the opening area of the hole in the joining surface increases, miniaturization of the liquid ejection head may be restricted. This problem is not limited to the substrate of the liquid ejection head, and generally, it may occur when manufacturing a structure by joining a member with a hole to another member using an adhesive. An object of the present invention is to provide a structure in which reduction in the cross-sectional area or blockage of the hole due to creeping of the adhesive hardly occurs.

Means for Solving the Problems

[0005] The structure of the present invention comprises a first member having a first joining surface, a second member having a second joining surface, and a first adhesive for bonding the first member and the second member. The first member has a first hole extending from the first joining surface, and the first hole has a central portion extending in a first direction and a side surface of the central portion extending in a circumferential direction. , 2 adjacent to each other in the first direction The first joint has two first grooves. The first adhesive is interposed between the first joint surface and the second joint surface and fills at least a portion of at least one of the first grooves. The first groove includes a first side wall extending from the opening of the first groove and a second side wall extending from the opening of the first groove and connecting with the first side wall at the bottom of the first groove. The angle between the first side wall and the second side wall is acute. In the first direction, at least a portion of the bottom of the first groove is located at a different position from the opening of the first groove. In the first direction, at least a portion of the bottom of one of the first grooves is in the same position as the opening of the other first groove. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a structure that is less prone to reduction in the cross-sectional area of ​​holes or blockage due to the adhesive spreading up. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram of a structure relating to one embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view of a hole created using the conventional Bosch process. [Figure 3] This is a schematic cross-sectional view showing various shapes of the first groove. [Figure 4] This is a schematic cross-sectional view showing the process flow for forming the first groove. [Figure 5] This is a schematic cross-sectional view showing the process flow of Example 1. [Figure 6] This is a schematic cross-sectional view showing the process flow of Example 2. [Figure 7] This is a schematic cross-sectional view showing the process flow of Example 3. [Modes for carrying out the invention]

[0008] A structure according to one embodiment of the present invention and a method for manufacturing the same will be described below with reference to the drawings. The embodiments described below are technically preferred examples, and the present invention is not limited to these embodiments. In the following description, the first direction Z is the direction in which the first hole (or its center line C) extends and is perpendicular to the first joining surface S1 of the first member 1.

[0009] Figure 1 shows a conceptual diagram of structure 1. Figure 1(a) is a plan view of structure 1, Figure 1(b) is a longitudinal cross-sectional view of structure 1 along the line 1b-1b in Figure 1(a), and Figure 1(c) is an enlarged view of part A in Figure 1(b). Structure 10 includes a first member 1 having a first joining surface S1, a second member 2 having a second joining surface S2, and a first adhesive B1 that bonds the first member 1 and the second member 2. The first adhesive B1 is interposed between the first joining surface S1 and the second joining surface S2, joining the first member 1 and the second member 2. The first joining surface S1 and the second joining surface S2 are planes parallel to each other. The first member 1 and the second member 2 are silicon substrates formed from silicon single crystals. The first adhesive B1 is made of epoxy resin.

[0010] The first member 1 has a first hole 11 extending from a first joint surface S1. The first hole 11 extends along a first direction Z perpendicular to the first joint surface S1. The cross-sectional shape of the first hole 11 parallel to the first joint surface S1 is square, but it may be rectangular or circular with two adjacent sides of different lengths. The corners of the first hole 11 are rounded, but may not be rounded. The first hole 11 has a central portion 12 extending in the first direction Z, and at least one first groove 13 extending circumferentially along the side surface 12A of the central portion 12. Numerous first grooves 13 are formed along the first direction Z. The central portion 12 is a roughly rectangular prism-shaped space extending in the first direction Z. The first groove 13 is a frame-shaped groove concentric with the central portion 12. As will be described later, the first groove 13 is formed by a modified Bosch process.

[0011] When the first joint surface S1 and the second joint surface S2 are pressure-bonded, the first adhesive B1 that has squeezed out from the gap between the first joint surface S1 and the second joint surface S2 may leak into the first hole 11. In this case, the first adhesive is captured and held in the first groove 13. Therefore, it is less likely that the cross-sectional reduction or blockage of the first hole 11 will occur due to the first adhesive B1 entering the first hole 11. The first adhesive B1 is filled sequentially starting from the first groove 13 closest to the first joint surface S1, but it is not necessary for all of the first grooves 13 to be filled with the first adhesive B1. Nor is it necessary for the entire circumference of the first groove 13 to be filled with the first adhesive B1. The first adhesive B1 only needs to fill at least a portion of at least one of the first grooves 13. Two adjacent first grooves 13 are provided without gaps in the first direction Z. As a result, when the first adhesive B1 fills one of the first grooves 13, any adhesive B1 that does not fit into that groove 13 easily enters the adjacent groove 13, thereby enhancing the effect of the first groove 13 in capturing and holding the first adhesive B1.

[0012] The first groove 13 extends in a direction inclined with respect to a plane perpendicular to the first direction Z as a whole. The first groove 13 has two sides 14A and 14B facing each other in the first direction Z, and the two sides 14A and 14B form an acute angle θ at the bottom 15 of the first groove 13. In a cross section parallel to the first direction, the two sides 14A and 14B extend in a straight line. For manufacturing reasons, the two sides 14A and 14B may be formed in a gently curved shape, but macroscopically they are generally straight. Figure 2 shows a longitudinal cross section of the first hole 111 formed by a normal Bosch process. In a normal Bosch process, a rounded, bowl-shaped scallop 112 (the uneven shape of the side wall formed by the Bosch process) is formed on the side of the first hole 111. Such scallops 112 have a low ability to capture and hold the first adhesive B1, making it easier for the first adhesive B1 to penetrate into the central part 12 of the first hole 11. In contrast, in this embodiment, the first groove 13 has an elongated shape and is sufficiently inclined with respect to a plane perpendicular to the first direction Z, thereby improving its ability to capture and hold the first adhesive B1. Since the first groove 13 is not exposed to the first joining surface S1, the ratio of the area of ​​the first hole 11 to the first joining surface S1 does not increase. Therefore, it is possible to suppress an increase in the size of the first member 1.

[0013] In the first direction Z, the bottom 15 of the first groove 13 is in a different position from the opening 16 of the first groove 13. That is, in a cross section parallel to the first direction Z, the perpendicular line drawn from the bottom 15 of the first groove 13 in a direction perpendicular to the first direction Z does not coincide with the opening 16 of the first groove 13. In other words, the two sides 14A and 14B of the first groove 13 that face each other in the first direction Z are on the same side with respect to a plane 17 that passes through the bottom 15 of the first groove 13 and is perpendicular to the first direction Z. The bottom 15 of the first groove 13 is the part furthest from the center line C in a cross section parallel to the first direction Z, and in this embodiment it is a point. In the first direction Z, it is preferable that the bottom 15 of the first groove 13 coincides with the opening 16 of the first groove 13 adjacent to the first groove 13. In other words, it is preferable that at least a portion of the bottom 15 of one of the two first grooves 13 adjacent to each other in the first direction Z is in the same position as the opening 16 of the other first groove 13. By inclining the first grooves 13 in this way, the ability to capture and hold the first adhesive B1 is further enhanced.

[0014] Preferably, the first groove 13 extends in a direction away from the first joining surface S1. In this case, in the first direction Z, at least a portion of the bottom 15 of the first groove 13 is on the opposite side of the first joining surface S1 with respect to the opening 16 of the first groove 13. By adjusting the orientation of the first groove 13 in this way, it becomes easier to capture the first adhesive B1 flowing into the first hole 11. In addition, the first adhesive B1 that has entered the first groove 13 is pushed into the first groove 13 by the first adhesive B1 that flows in later, so the ability to capture and hold the first adhesive B1 is further enhanced. The first groove 13 may also extend in a direction toward the first joining surface S1.

[0015] The shape of the first groove 13 is not limited to the example of FIG. 1, and the first groove 13 can take various shapes. Various shapes of the first groove 13 are shown in FIG. 3. As shown in FIG. 3(a), a gap G may be formed between two adjacent first grooves 13. As shown in FIG. 3(b), the vicinity of the bottom 15 may be rounded. As shown in FIG. 3(c), the side surfaces 14A, 14B of the first groove 13 may be curved surfaces. As shown in FIG. 3(d), the first groove 13 may include a large number of vertices. In the illustrated example, the bottom 15 has a width in the first direction Z. In this case, at least a part of the bottom 15 may be at a position different from the opening 16 of the first groove 13, and preferably the entire bottom 15 is at a position different from the opening 16 of the first groove 13. Although illustration is omitted, the side surfaces 14A, 14B of the first groove 13 may be composed of straight lines and curves.

[0016] Next, a method for forming the structure 10 described above, particularly the first hole 11 provided with the first groove 13, will be described. The structure 10 is formed by sequentially performing the following steps. - A step of forming a first hole 11 extending from the first joint surface S1 in a first member 1 having the first joint surface S1 - A step of bonding the first member 1 in which the first hole 11 is formed and a second member 2 having a second joint surface S2 with a first adhesive B1 As described above, the first adhesive B1 is interposed between the first joint surface S1 and the second joint surface S2 and fills at least a part of at least one first groove 13. In the present embodiment, the first hole 11 is formed by a Bosch process of dry etching. The Bosch process is an etching process that repeats etching and side wall protection, and in the present embodiment, a conventional Bosch process is partially modified and applied. Hereinafter, a method for forming the first hole 11 will be described.

[0017] Figure 4 schematically shows the process of forming the first groove 13. Figure 4 shows, in chronological order, the steps of forming one first groove 13 with a first hole 11. The Bosch process includes a recess forming step of forming a recess 18 with a scallop 19 recessed in a curved shape on the side surface of the first member 1, and a groove forming step of forming the first groove 13 from the scallop 19. By performing the recess forming step and the groove forming step, a part of the first hole 11 including only one first groove 13 is formed. Figure 4 shows only a part of this first hole 11. By repeatedly performing the steps having the recess forming step and the groove forming step, the first hole 11 is formed. The first hole 11 is formed from the first joint surface S1 toward the opposite surface.

[0018] The recess forming step is not particularly different from the conventional Bosch process, and a recess 18 as shown in Fig. 4(a) is formed under the same etching conditions as in the conventional process. An etching mask 41 for preventing the etching of the first member 1 is formed around the portion where the first hole 11 is formed on the first joint surface S1 of the first member 1 (see Figs. 5(b), 6(b), and 7(b)). Next, the groove forming step is performed. The groove forming step consists of the following sub-steps. - A protective film forming step of forming a protective film 20 on the surface of the scallop 19 (Fig. 4(b)) - A protective film etching step of removing the protective film 20 formed on the side of the scallop 19 away from the first joint surface S1 by etching with ions 51 (Fig. 4(c)) - A member etching step of removing the first member 1 by etching with radicals 52 from the portion removed by etching (Fig. 4(d)) In the recess forming step, these three steps are repeated.

[0019] The three substeps can be performed by adjusting the pressure of the introduction gas into the chamber and the execution time of each step. Etching conditions can also be changed by changing the coil power, bias, and flow rate of the introduction gas. Specific examples will be explained in the examples, but in summary, the etching conditions are controlled as follows. - The pressure of the introduced gas in the protective film formation step is made greater than the pressure of the introduced gas in the recess formation step. - The pressure of the gas introduced during the component etching step is made greater than the pressure of the gas introduced during the recess formation step. - The execution time of the protective film formation step is made longer than the execution time of the protective film formation step in the recess formation step.

[0020] The Bosch process exhibits etching anisotropy due to ion pull in the direction of its progression. Therefore, in the protective film etching step, the protective film 20 on the side of a scallop 19 furthest from the opening 18A of the recessed portion 18 (see Figure 5(d)) is more easily removed. In other words, the protective film 20 on the downstream side of the Bosch process within a scallop 19 is more easily removed. In a typical Bosch process, the etching conditions in the protective film formation step and the protective film etching step are adjusted so that the entire protective film 20 within a single scallop 19 remains intact. In contrast, in this embodiment, the etching conditions in the protective film formation step and the protective film etching step are adjusted so that the protective film 20 furthest from the opening 18A is selectively removed. The thickness of the protective film 20 may be thinner than in a typical Bosch process, or the amount of etching may be increased to increase the thickness of the protective film 20 that can be removed compared to a typical Bosch process.

[0021] In the component etching step, the areas of the first component 1 where the protective film 20 was selectively removed in the protective film etching step are etched by radicals 52. This causes the groove to grow in the direction of the Bosch process. Also, since the protective film 20 at the bottom of the recessed portion 18 was removed in the protective film etching step, the area directly below the recessed portion 18 is also etched, increasing the depth of the recessed portion 18. The protective film formation step (Figure 4(e)), protective film etching step (Figure 4(f)), and component etching step (Figure 4(g)) are performed again, and these steps are repeated (Figures 4(h) to (j)). Although not shown in the illustration, in Figures 4(e) to (g), a new groove is formed on the lower side (in the direction of the Bosch process), and in Figures 4(h) to (j), a new groove is formed even further down. In other words, the first groove 13 shown in Figure 4 is formed in stages as the recessed portion 18 is excavated below it.

[0022] In the second protective film etching step shown in Figure 4(f), the scallop 19 bulges downward, casting a shadow on the deeper part of the groove to the ions 51, making it less susceptible to etching by the ions 51. In the third protective film etching step shown in Figure 4(i), the groove has grown further, making it even less susceptible to etching by the ions 51. Therefore, the growth of the groove stops when it has reached a certain depth. The first groove 13 formed in the shallow part of the first hole 11 then undergoes repeated protective film etching steps to form the deeper part of the first hole 11, but once a certain stage is reached, the protective film 20 is no longer removed. This forms the first groove 13 as shown in Figure 4(k).

[0023] (Example 1) As examples of applications of the present invention, several embodiments will be described. All embodiments described below are flow path members for a liquid discharge head. Figure 5 is a schematic cross-sectional view showing the process of creating a liquid discharge flow path by joining a first member 1 and a second member 2. Both the first member 1 and the second member 2 are silicon substrates. The first hole 11 is an ink flow path. First, as shown in Figure 5(a), a first member 1 with a thickness of 625 μm was prepared. Next, as shown in Figure 5(b), a photoresist 41 was applied to the first joining surface S1 of the first member 1 to a thickness of 17.5 μm. Next, as shown in Figure 5(c), an etching mask 42 having an opening was fabricated by irradiating the photoresist 41 with ultraviolet light and developing it. The opening of the etching mask 42 was a square shape with a vertical dimension of 45 μm and a horizontal dimension of 45 μm when viewed from the surface of the etching mask 42. Next, as shown in Figure 5(d), a modified Bosch process was performed, repeating the recess formation step and the groove formation step. From the first bonding surface S1 side, silicon etching using SF6 was performed via an etching mask 42 to form a first hole 11 with a depth of 80 μm and a first groove 13 with a depth of 2 μm. Only the portion of the scallop 19 furthest from the first bonding surface S1 was selectively etched, forming a long, slender, inclined first groove 13 as shown in Figure 5(d). Note that Figure 5(d) is a schematic diagram, and the actual number of first grooves 13 is greater.

[0024] In this embodiment, the etching conditions were modified as follows from the etching conditions for creating a typical scallop 112 shown in Figure 2 (hereinafter referred to as the reference example; the etching rate of the reference example is 4 μm / min). First, the pressure of the introduced gas in the protective film etching step was set to 150% of that of the reference example. This is to improve the removal capability of the protective film 20 and to selectively remove the protective film 20. The pressure of the introduced gas in the component etching step was set to 300% of that of the reference example. This is to promote isotropic etching for forming the first groove 13. The execution time of the protective film formation step was changed to 150% of that of the reference example (the pressure of the introduced gas was kept the same as that of the reference example). This is to prevent abnormalities such as rupture of the protective film 20 caused by changes in other etching conditions.

[0025] Finally, as shown in Figure 5(e), the etching mask 42 was removed, and as shown in Figure 5(f), a second member 2 was prepared, and the first bonding surface S1 and the second bonding surface S2 were heat-pressurized and bonded with a first adhesive B1 made of epoxy resin. As a result, the first hole 11 became a liquid chamber through which ink flowed. The first adhesive B1 crawled up the side of the first hole 11 toward the back of the first hole 11, but was held in place by the elongated first groove 13, which suppressed its crawling. In this way, a liquid chamber for the liquid ejection head was obtained while suppressing the crawling of the first adhesive B1 into the first hole 11 by the first groove 13. (Example 2)

[0026] Figure 6 is a schematic cross-sectional view showing the process of creating a liquid discharge channel by joining a first member 1 and a second member 2. Both the first member 1 and the second member 2 are silicon substrates. The first member 1 has a first hole 11, and the second member 2 has a second hole 12 that communicates with the first hole 11. The first hole 11 and the second hole 12 are ink channels. Unlike Example 1, the first hole 11 penetrates the first member 1. The steps in Figures 6(a) to (c) and (e) to (f) are the same as in Example 1, so their explanation is omitted. The material and dimensions of the first member, the size of the opening of the etching mask 42, etc., are also the same as in Example 1. In this example as well, the execution time of the protective film formation step was set to 150% of the reference example, the pressure of the introduced gas in the protective film etching step was set to 150% of the reference example, and the pressure of the introduced gas in the member etching step was set to 300% of the reference example.

[0027] In this embodiment, the process of forming the recessed portion 18 was not terminated midway, but continued until the recessed portion 18 reached the back surface. As a result, a first hole 11 in the shape of a through hole was obtained, as shown in Figure 6(d). The etching conditions of the first member 1 were kept the same until the recessed portion 18 reached the back surface, but no elongated, inclined grooves like the first groove 13 were formed in the later-formed portion of the first hole 11. In other words, with respect to at least one first groove 13, at least one second groove 23 with a different shape from the first groove 13 was formed on the opposite side of the first joining surface S1. The second groove 23 extends circumferentially along the side surface 12A of the central portion 12, similar to the first groove 13. The first groove 13 is provided in part of the total length of the first hole 11, and the second groove 23 is provided in the remaining part of the total length of the first hole 11. This is because, as the depth of the recessed portion 18 increases, the aspect ratio of the recessed portion 18 (depth of recessed portion 18 / area of ​​the opening 16 of recessed portion 18) increases, making the protective film 20 less susceptible to etching. As a result, in the deeper parts of the recessed portion 18, a second groove 23 with a scallop shape similar to that formed in a normal Bosch process is formed. That is, in the first direction Z, at least a portion of the bottom 15 of the second groove 23 is in the same position as the opening 16 of the second groove 23. As described above, the first groove 13 suppresses the crawling of the first adhesive B1 into the first hole 11 while providing a liquid discharge path for the liquid discharge head. Note that in Figures 6(d) to (f), the first groove 13 and the second groove 23 are all shown with the same shape, but as can be understood from the above explanation, the shape of the grooves changes in stages. As the depth at which the groove is formed increases, the bottom 15 of the groove comes into contact with the opening 16 of the groove in the first direction Z, and the groove transitions from the first groove 13 to the second groove 23.

[0028] (Example 3) Figure 7 is a schematic cross-sectional view showing the process of creating a liquid discharge channel by joining the first to third members 1, 2, and 3. The first member 1 has a first hole 11, the second member 2 has a second hole 12 communicating with the first hole 11, and the third member 3 has a third hole 31 communicating with the first hole 11. The first to third holes 11, 21, and 31 are ink channels. The structure 10 of this embodiment includes a first member 1 having a first joining surface S1, a second member 2 having a second joining surface S2, and a third member 3 having a third joining surface S3. The first to third members 1, 2, and 3 are silicon substrates. The structure 10 includes a first adhesive B1 for bonding the first member 1 and the second member 2, and a second adhesive B2 for bonding the first member 1 and the third member 3. The first member 1 has a fourth joining surface S4 which is the back surface of the first joining surface S1. The second adhesive B2 is made of epoxy resin, similar to the first adhesive B1.

[0029] Similar to Example 2, the first hole 11 extends to the fourth bonding surface S4 and penetrates the first member 1. The steps in Figures 7(a) to (e) are the same as in Example 1, so their explanation is omitted. The material and dimensions of the first member 1, and the size of the opening of the etching mask 42 are also the same as in Example 1. In this example as well, similar to Example 1, the execution time of the protective film formation step was set to 150% of the reference example, the pressure of the introduced gas in the protective film etching step was set to 150% of the reference example, and the pressure of the introduced gas in the member etching step was set to 300% of the reference example.

[0030] Next, the first member 1 was flipped upside down, and as shown in Figures 7(f) to (i), a recess 18A was created from the fourth bonding surface S4. The specific method is the same as in Example 1, so the explanation is omitted. The etching time was set so that the target depth of the dry etching was 320 μm or more, so that the recess 18A created later would merge with the recess 18 created first within the first member 1 to form a single first hole 11. Through the above process, at least one first groove 13 was formed on the first bonding surface S1 side of the first hole 11, and at least one third groove 33 was formed on the fourth bonding surface S4 side of the first hole 11. Since the first groove 13 and the third groove 33 were formed under the same etching conditions, they have substantially the same shape.

[0031] Next, a second member 2 having a second hole 12 measuring 30 μm × 30 μm, and a third member 3 having a third hole 31 measuring 30 μm × 30 μm were prepared and joined to both sides of the first member 1 (the first joining surface S1 and the fourth joining surface S4) as shown in Figure 7(j). Specifically, the first joining surface S1 of the first member 1 and the second joining surface S2 of the second member 2 were heat-pressurized and joined using a first adhesive B1, which is an epoxy resin. Subsequently, the fourth joining surface S4 of the first member 1 and the third joining surface S3 of the third member 3 were heat-pressurized and joined using a second adhesive B2, which is an epoxy resin. The first adhesive B1 is interposed between the first joining surface S1 and the second joining surface S2 and fills at least a portion of at least one of the first grooves 13. The second adhesive B2 is interposed between the third joining surface S3 and the fourth joining surface S4, and fills at least a portion of at least one of the third grooves 33. As described above, the first groove 13 and the third groove 33 suppress the crawling of the first and second adhesives B1 and B2 into the first hole 11, while a liquid discharge path for the liquid discharge head is obtained.

[0032] In this embodiment, as shown in Figure 7(i), at least one second groove 23, different from the first groove 13 and the third groove 33, is formed in the central part 12 of the first hole 11, that is, between the first groove 13 and the third groove 33. The second groove 23 is a groove that extends circumferentially along the side surface 12A of the central part 12 of the first hole 11. The first groove 13 and the third groove 33 are elongated and inclined grooves. In the first direction Z, at least a portion of the bottom 15 of the first groove 13 is in a different position from the opening 16 of the first groove 13, and at least a portion of the bottom 15 of the third groove 33 is in a different position from the opening 16 of the third groove 33. In contrast, the second groove 23 was a groove having a scallop 19 with a shape similar to that formed in a normal Bosch process. In other words, in the first direction Z, at least a portion of the bottom 15 of the second groove 23 is in the same position as the opening 16 of the second groove 23. Such grooves are formed for the same reasons as the second groove 23 in Embodiment 2. Depending on the aspect ratio of the first hole 11, the second groove 23 may not be formed. In this case, the first groove 13 is provided in a portion of the total length of the first hole 11, and the third groove 33 is provided in the remaining portion of the total length of the first hole 11. Also, in this embodiment, since recessed portions 18, 18A are created from the first joining surface S1 and the fourth joining surface S4, the first groove 13 faces the direction of the third groove 33, and the third groove 33 faces the direction of the first groove 13. Therefore, the first adhesive B1 and the second adhesive are well captured and held in the first groove 13 and the third groove 33, respectively. [Explanation of symbols]

[0033] 1. First member 2. Second member 11 The first hole 12 Central part 13 The first trench B1 First adhesive S1 First joint surface S2 Second bonding surface

Claims

1. It comprises a first member having a first joining surface, a second member having a second joining surface, and a first adhesive for bonding the first member and the second member together. The first member has a first hole extending from the first joining surface, The first hole has a central portion extending in a first direction, and two first grooves extending circumferentially from the side surface of the central portion and adjacent to each other in the first direction, The first adhesive is interposed between the first joining surface and the second joining surface and fills at least a portion of the at least one first groove. The first groove includes a first side wall extending from the opening of the first groove, and a second side wall extending from the opening of the first groove and connecting with the first side wall at the bottom of the first groove. The angle between the first side wall and the second side wall is acute. In the first direction, at least a portion of the bottom of the first groove is in a position different from the opening of the first groove. A structure wherein, in the first direction, at least a portion of the bottom of one of the first grooves is in the same position as the opening of the other first groove.

2. The structure according to claim 1, wherein, in the first direction, the entire bottom of the first groove is located at a different position from the opening of the first groove.

3. The structure according to claim 1 or 2, wherein, in the first direction, at least a portion of the bottom of the first groove is on the opposite side of the first joint surface with respect to the opening of the first groove.

4. The structure according to claim 1, wherein in a cross-section parallel to the first direction, the first side wall and the second side wall extend in a straight line.

5. The structure according to claim 1, wherein the two first grooves are provided without gaps in the first direction.

6. A first member having a first joining surface, a second member having a second joining surface, and a first adhesive for bonding the first member and the second member, The first member has a first hole extending from the first joining surface, The first hole has a central portion extending in a first direction and at least one first groove extending circumferentially along the side surface of the central portion. The first adhesive is interposed between the first joining surface and the second joining surface and fills at least a portion of the at least one first groove. The first groove includes a first side wall extending from the opening of the first groove, and a second side wall extending from the opening of the first groove and connecting with the first side wall at the bottom of the first groove. The angle between the first side wall and the second side wall is acute. In the first direction, at least a portion of the bottom of the first groove is in a position different from the opening of the first groove. A structure having at least one second groove located on the opposite side of the first joint surface with respect to the at least one first groove, wherein the at least one second groove extends circumferentially along the side surface of the central portion, and in the first direction, at least a portion of the bottom of the second groove is in the same position as the opening of the second groove.

7. The structure according to claim 6, wherein the first groove is provided in a portion of the total length of the first hole, and the second groove is provided in the remaining portion of the total length of the first hole.

8. A first member having a first joining surface, a second member having a second joining surface, and a first adhesive for bonding the first member and the second member, The first member has a first hole extending from the first joining surface, The first hole has a central portion extending in a first direction and at least one first groove extending circumferentially along the side surface of the central portion. The first adhesive is interposed between the first joining surface and the second joining surface and fills at least a portion of the at least one first groove. The first groove includes a first side wall extending from the opening of the first groove, and a second side wall extending from the opening of the first groove and connecting with the first side wall at the bottom of the first groove. The angle between the first side wall and the second side wall is acute. In the first direction, at least a portion of the bottom of the first groove is in a position different from the opening of the first groove. It comprises a third member having a third joining surface, and a second adhesive for bonding the first member and the third member, The first member has a fourth joining surface which is the back surface of the first joining surface, The first hole extends to the fourth joining surface, The first hole has at least one third groove extending circumferentially along the side surface of the central portion, The at least one first groove is located on the side of the first joint surface, and the at least one third groove is located on the side of the fourth joint surface. The second adhesive is interposed between the third joint surface and the fourth joint surface and fills at least a portion of the at least one third groove. The third groove includes a third side wall extending from the opening of the third groove, and a fourth side wall extending from the opening of the third groove and connecting with the third side wall at the bottom of the third groove. The angle between the third side wall and the fourth side wall is acute. A structure wherein, in the first direction, at least a portion of the bottom of the third groove is located at a different position from the opening of the third groove.

9. The structure according to claim 8, wherein the first groove faces the direction of the third groove, and the third groove faces the direction of the first groove.

10. The first groove extends in a direction away from the first joint surface, The structure according to claim 8, wherein the third groove extends in a direction away from the fourth joint surface.

11. The structure according to claim 8 or 9, wherein the first groove is provided in a portion of the total length of the first hole, and the third groove is provided in the remaining portion of the total length of the first hole.

12. The structure according to claim 8 or 9, wherein the structure is located between the at least one first groove and the at least third groove, and has at least one second groove extending in the circumferential direction on the side surface of the central portion, and in the first direction, at least a portion of the bottom of the second groove is in the same position as the opening of the second groove.

13. The first member and the second member are flow path members of the liquid discharge head. The second member has a second hole that communicates with the first hole of the first member. The structure according to any one of claims 1 to 12, wherein the first hole and the second hole are ink channels.

14. A first member, which is a silicon substrate having a first bonding surface, has a first hole extending from the first bonding surface. The first member having the first hole formed therein and the second member having the second joining surface are bonded together with the first adhesive, The first hole has a central portion extending in a first direction and at least one first groove extending circumferentially along the side surface of the central portion. The first adhesive is interposed between the first joining surface and the second joining surface and fills at least a portion of the at least one first groove. The first groove includes a first side wall extending from the opening of the first groove, and a second side wall extending from the opening of the first groove and connecting with the first side wall at the bottom of the first groove. The angle between the first side wall and the second side wall is acute. In the first direction, at least a portion of the bottom of the first groove is in a position different from the opening of the first groove. The first hole is formed by a dry etching Bosch process. The Bosch process includes a recessing step of forming recesses in the first member, in which curved, recessed scallops are formed on the side surface, and a groove forming step of forming a first groove from the scallops. A method for manufacturing a structure, wherein the groove forming step is repeatedly performed: a protective film forming step of forming a protective film on the scallops; a protective film etching step of removing the protective film formed on the side of each scallop away from the first bonding surface by etching; and a member etching step of removing the first member from the portion removed by etching.

15. A method for manufacturing a structure according to claim 14, comprising repeating the steps of forming the recessed portion and forming the groove.

16. A method for manufacturing a structure according to claim 14 or 15, wherein the pressure of the introduced gas in the protective film formation step is greater than the pressure of the introduced gas in the recess formation step, the pressure of the introduced gas in the member etching step is greater than the pressure of the introduced gas in the recess formation step, and the time of the protective film formation step is longer than the time of the protective film formation step in the recess formation step.

17. A method for manufacturing a liquid ejection head, comprising a method for manufacturing a structure according to any one of claims 14 to 16, wherein the first member and the second member are flow path members of a liquid ejection head, the second member has a second hole communicating with the first hole of the first member, and the first hole and the second hole are ink flow paths.

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