Substrate joined body, liquid discharge head and method for manufacturing the same

Abstract

To provide a substrate joined body that can grasp a joint gap during and after joining substrates in a non-destructive manner, and to provide a liquid discharge head and a method for manufacturing the same.SOLUTION: A substrate joined body 1 includes at least a pair of substrates 11, 12 laminated via an adhesive material layer 2. The adhesive material layer 2 is provided with a plurality of opening parts 3 penetrating the adhesive material layer 2 in a lamination direction of the pair of substrates 11, 12. At least two of the opening parts 3 are arranged while being arrayed in parallel with any one side of an outer shape of at least one of the pair of substrates 11, 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a substrate assembly, a liquid ejection head, and a method for manufacturing the same. [Background technology]

[0002] In recent years, substrate assemblies having a complex three-dimensional structure formed by bonding multiple substrates such as Si wafers have been used to improve the functionality and integration of functional devices such as MEMS (Micro Electro Mechanical Systems) devices. One example of a method for bonding multiple substrates such as Si wafers to form such a substrate assembly is a method of stacking the substrates together via an adhesive. Patent Document 1 describes a method in which a pair of wafers stacked via an adhesive are sandwiched and pressed between a pair of press plates having main surfaces larger than the wafers, thereby reducing the surface accuracy of the bonding surfaces of the wafers and bonding the pair of wafers to each other while making the main surfaces of the pair of wafers parallel to each other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-48141 A Summary of the Invention [Problem to be solved by the invention]

[0004] When pressing a substrate using a press plate, the bonding gap (the distance between substrates) may vary due to abnormalities in the manufacturing equipment, such as deterioration of the surface accuracy of the press plate or adhesion of foreign matter to the press plate, or adhesion of foreign matter to the bonding surfaces of the substrates, resulting in variation in the bonding state between the substrates. When such a substrate bond is incorporated into a device, the performance of the device may vary, leading to a decrease in yield and a decrease in quality. However, the method described in Patent Document 1 and the like cannot easily and nondestructively grasp the variation in the bonding gap during and after bonding of the substrates, and therefore cannot prevent the variation in device performance.

[0005] An object of the present invention is to provide a substrate bonded assembly and a liquid ejection head that are capable of non-destructively determining the bonding gap during and after bonding of substrates, and a method for manufacturing the same. [Means for solving the problem]

[0006] The substrate assembly of the present invention comprises at least a pair of substrates stacked together via an adhesive layer, the adhesive layer being provided with a plurality of openings penetrating the adhesive layer in the stacking direction of the pair of substrates, and at least two of the plurality of openings being arranged in parallel to one side of the outer shape of at least one of the pair of substrates. Effect of the Invention

[0007] According to the present invention, it is possible to obtain a bonded substrate assembly and a liquid ejection head that make it possible to non-destructively grasp the bonding gap during and after bonding of the substrates. [Brief description of the drawings]

[0008] [Figure 1] 1A and 1B are a schematic perspective view and a schematic cross-sectional view of a substrate assembly according to a first embodiment of the present invention. [Diagram 2] 2 is an exploded perspective view of the substrate assembly shown in FIG. 1. [Diagram 3] 2A to 2C are cross-sectional views and plan views showing in sequence the steps of joining substrates in the substrate assembly shown in FIG. [Figure 4] 10A and 10B are plan views showing preferred examples of the arrangement of a plurality of openings in an adhesive layer. [Diagram 5] 10A and 10B are plan views showing preferred examples of the arrangement of a plurality of openings in an adhesive layer. [Figure 6] 13 is a plan view showing another example of a plurality of openings in the adhesive layer. FIG. [Figure 7] FIG. 2 is a perspective view of a wafer-shaped substrate bonded body. [Figure 8] 5A to 5C are cross-sectional views and plan views sequentially illustrating steps of joining substrates in a substrate assembly according to a second embodiment of the present invention. [Figure 9] 13A to 13C are cross-sectional views and plan views sequentially illustrating steps of joining substrates in a substrate assembly according to a third embodiment of the present invention. [Figure 10] 13A to 13C are cross-sectional views and plan views sequentially illustrating steps of joining substrates in a substrate assembly according to a fourth embodiment of the present invention. [Figure 11] 1A and 1B are schematic perspective and cross-sectional views of a liquid ejection head including a substrate assembly according to first and second embodiments of the present invention. [Figure 12] 12A to 12C are cross-sectional views sequentially illustrating some steps of a method for manufacturing the liquid ejection head shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the specific configuration of the embodiment described below. [First embodiment] FIG. 1(A) is a schematic perspective view of a substrate assembly 1 according to a first embodiment of the present invention, and FIG. 1(B) is a cross-sectional view taken along line AA in FIG. 1(A). FIG. 2 is an exploded perspective view of the substrate assembly 1. FIGS. 3(A1), 3(B1), and 3(C1) are cross-sectional views showing the bonding process of substrates 11 and 12 in sequence, and FIGS. 3(A2), 3(B2), and 3(C2) are plan views showing the bonding process in sequence. The substrate assembly 1 has at least a pair of substrates 11 and 12 stacked on top of each other, and an adhesive layer 2 interposed between the substrates 11 and 12. The adhesive layer 2 has an opening 3. The substrates 11 and 12 are stacked with the adhesive layer 2 interposed therebetween, and the bonding surfaces of both substrates 11 and 12 are bonded to each other in contact with the adhesive layer 2. The substrates 11 and 12 constituting the substrate assembly 1 are formed of materials such as Si, glass, ceramics, semiconductors, and resins. Although not shown, the substrates 11 and 12 may be processed substrates having grooves or through holes formed therein or having integrated circuits or functional devices mounted thereon, or may be bare substrates that have not been subjected to such processing. Note that the substrates 11 and 12 may be further stacked with one or more other substrates (not shown) so that the substrate assembly 1 has three or more substrates.

[0010] The adhesive layer 2 is made of a material having adhesiveness to the substrates 11 and 12, such as a thermoplastic resin, a metal, or an oxide film. In the manufacturing method of the substrate assembly 1, the adhesive layer 2 is formed as follows. First, the adhesive layer 2 is formed on the bonding surface (the surface of the substrates 11 and 12 facing each other) of one substrate (substrate 11 in the example shown in Figs. 3(A1) and 3(A2)) of the pair of substrates 11 and 12 before bonding, as shown in Figs. 3(B1) and 3(B2). In the following description, the adhesive layer 2 is formed on the substrate 11, but this is not limited thereto, and the adhesive layer 2 may be applied to the substrate 12. As shown in Figs. 3(C1) and 3(C2), the bonding surfaces of the substrates 11 and 12 are placed face to face with each other, overlapped with the adhesive layer 2 interposed therebetween, and pressed using a press plate or the like (not shown). In Fig. 3(C2), the upper substrate 12 is omitted. In order to reliably bond the substrates 11 and 12 together, it is necessary to prevent the occurrence of voids in the adhesive layer 2 due to the inclusion of air bubbles during bonding or the influence of foreign matter. For this reason, it is preferable to form the adhesive layer 2 as thick as possible on the bonding surface of the substrate 11. However, depending on the material of the adhesive layer 2, if the film thickness is too thick, there is a risk that excess adhesive will protrude outside the substrates 11 and 12 during pressing. If the adhesive that protrudes in this way covers the edges or internal active regions of the substrates 11 and 12, it may adversely affect the performance of the device in which the substrate bonded body 1 is incorporated. Therefore, the thickness of the adhesive layer 2 needs to be set precisely. When using the substrates 11 and 12 made of Si and the adhesive layer 2 made of a thermoplastic resin, it is preferable to form the adhesive layer 2 to a thickness of about 0.1 μm to 10 μm, and thin the adhesive layer 2 to 1 μm or less (submicron units) after pressing the substrates 11 and 12 together.

[0011] In this embodiment, an opening 3 is formed in the adhesive layer 2. The opening 3 functions as a means for easily and non-destructively grasping the bonding gap G (the gap between the substrates 11 and 12, see FIG. 1(B)) during and after bonding, that is, the thickness of the adhesive layer 2. Specifically, as shown in FIGS. 3(B1) and 3(B2), an area (opening 3) where no adhesive is present is formed in advance inside the formed adhesive layer 2. The opening 3 is formed to a preset height and area. Therefore, the area and height of the planar shape of the opening 3 are known in advance. When the substrates 11 and 12 are bonded to each other, the adhesive layer 2 is sandwiched between the substrates 11 and 12 positioned above and below and is pressurized, so that the planar shape expands. As a result, as shown in FIGS. 3(C1) and 3(C2), the opening 3 is deformed so that the planar shape becomes smaller. The bonding gap G can be obtained by measuring the area of ​​the planar shape of the opening 3. The opening 3 of the adhesive layer 2 after the substrates 11 and 12 are bonded is optically observed using visible light (when at least one of the substrates 11 and 12 is made of a light-transmitting material such as glass) or infrared light (when the substrates 11 and 12 are made of a light-opaque material), and the area is determined by image processing. The area of ​​the planar shape of the opening 3 of the adhesive layer 2 after the substrates 11 and 12 are bonded thus obtained is compared with the area of ​​the planar shape of the opening 3 of the adhesive layer 2 before the substrates 11 and 12 are bonded, which is known in advance, to determine the bonding gap G at the position of the opening 3. In other words, the bonding gap G can be calculated based on the premise that the change in thickness of the adhesive layer 2 before and after the bonding of the substrates 11 and 12 and the change in the area of ​​the planar shape of the opening 3 ideally occur at the same rate. Specifically, the bond gap G is calculated by the formula: [bond gap G after bonding of substrates 11, 12 (thickness of adhesive layer 2 after bonding)] = [area of ​​planar shape of opening 3 after bonding ÷ area of ​​planar shape of opening 3 before bonding] × [thickness of adhesive layer 2 before bonding]. Similarly, by measuring the area of ​​the planar shape of opening 3 midway through the bonding process of substrates 11, 12, the bond gap G at that time point can be obtained.That is, the bonding gap G is calculated by the formula: [bonding gap G at the time of area measurement (thickness of adhesive layer 2 at the time of area measurement)] = [area of ​​the planar shape of opening 3 at the time of area measurement ÷ area of ​​the planar shape of opening 3 before bonding of substrates 11, 12] × [thickness of adhesive layer 2 before bonding]. If the area of ​​the planar shape of opening 3 provided in adhesive layer 2 is too large, it leads to a decrease in adhesive strength, and if it is too small, it becomes difficult to measure the area of ​​the planar shape of opening 3 after bonding of substrates 11, 12, and also difficult to stably form opening 3. In consideration of these circumstances, the area of ​​the planar shape of opening 3 provided in adhesive layer 2 is set to about 100 μm. 2 More than 100000μm 2 It is preferable to set it to about the following value.

[0012] The adhesive layer 2 of this embodiment is provided with a plurality of openings 3. This allows the variation in the bonding gap G inside the substrate assembly 1 to be grasped. That is, by obtaining the respective bonding gaps at the positions of the plurality of openings 3, the local variation in the bonding gap of the substrate assembly 1 and the tendency of the variation in the bonding gap in a plane parallel to the main surfaces of the substrates 11 and 12 can be grasped. Understanding the variation in the bonding gap G after the substrates 11 and 12 are bonded is useful for understanding the variation in the bonding strength. Based on this, feedback can be provided so as to appropriately adjust the driving conditions of a device in which the substrate assembly 1 is incorporated and the mounting conditions when the substrate assembly 1 is attached to another member. In addition, by grasping the variation in the bonding gap G during the bonding process of the substrates 11 and 12, the bonding process (for example, the pressure conditions of the substrates 11 and 12) can be managed so that the variation in the bonding gap G after the substrates 11 and 12 are reduced.

[0013] By arranging many openings 3, the bonding state of the substrates 11 and 12 can be grasped in detail. This point will be explained. Although not shown in the drawing, there are cases where the bonding gap G differs depending on the location in a plane parallel to the main surface of the substrates 11 and 12 (there is variation in the bonding gap G). In such a case, the average value of the bonding gap calculated from the area of ​​the planar shape of each of the openings 3 in the adhesive layer 2 is regarded as the bonding gap of the substrate assembly 1. By determining each bonding gap at many locations, the average bonding gap of the entire substrates 11 and 12 can be determined with high accuracy, and further, the tendency of the variation in the bonding gap G of the substrates 11 and 12 can be known, and the variation in the bonding state can be known. In such cases, in order to improve accuracy, it is preferable to provide many openings 3 in the adhesive layer 2 at equal intervals. However, if the number of openings 3 is large, there is a risk of the bonding strength decreasing.

[0014] Therefore, it is preferable to precisely and efficiently obtain the variation in the bonding gap G while keeping the number of openings 3 small by devising the arrangement of the openings 3. Specifically, as shown in Figs. 1 to 3, it is preferable to arrange the openings 3 so that a straight line L connecting the openings 3 (more specifically, the center points of the planar shapes of the openings 3) is parallel to any side of the outer shape of the substrate assembly 1. That is, it is preferable that at least two of the openings 3 are arranged parallel to any side of the outer shape of the substrate assembly 1. As will be described later, it is also preferable to arrange the openings 3 so that a straight line connecting the openings 3 (more specifically, the center points of the planar shapes of the openings 3) passes through a central position 4 (see Figs. 4 and 5) of the planar shape of the substrate assembly 1. That is, it is also preferable that at least two of the openings 3 are arranged on a single straight line passing through the central position 4 of the planar shape of the substrate assembly 1. By arranging the openings 3 in this way, the average joint gap G of the entire substrates 11 and 12 can be obtained with high accuracy, and the tendency of the change in the joint gap G inside the substrate assembly 1, i.e., the tendency of the variation in the joint state of the substrates 11 and 12 can be efficiently grasped. When the openings 3 are arranged so that the straight line L connecting the multiple openings 3 extends parallel to any side of the substrate assembly 1 and each joint gap is obtained based on the area of ​​the openings 3, the distribution of the joint gap along the side of the substrate assembly 1 can be obtained. When the openings 3 are arranged so that the straight line connecting the multiple openings 3 passes through the center position 4 of the planar shape of the substrate assembly 1 and each joint gap is obtained based on the area of ​​the openings 3, the distribution of the joint gap along the straight line passing through the center position 4 of the substrate assembly 1 can be obtained. By knowing the distribution of the joint gap along these straight lines, the variation of the entire joint gap G of the substrates 11 and 12 can be estimated. In particular, by determining the distribution of the bonding gap along a line passing through the center of the substrate assembly 1 or a line parallel to an edge of the substrate assembly 1, the distribution of the bonding gap, and therefore the variation in the bonding state of the substrates 11, 12, can be intuitively understood and efficiently grasped. However, the openings 3 may be provided at positions deviating from the line passing through the center of the substrate assembly 1 or the line parallel to an edge of the substrate assembly 1.

[0015] 4 and 5 show schematic examples of preferred arrangements of the openings 3 in the adhesive layer 2. FIGS. 4(A) to 4(F) show an example in which the openings 3 are arranged such that the straight lines L, L1, and L2 connecting the openings 3 are parallel to any side of the outer shape of the substrate assembly 1, similar to the configurations shown in FIGS. 1 to 3. In the example shown in FIG. 4(A), one opening 3 is removed from the configurations shown in FIGS. 1 to 3, and three openings 3 are provided. The three openings 3 are arranged to form a straight line L1 parallel to one side of the substrate assembly and another straight line L2 parallel to the other side of the substrate assembly. The three openings 3 include an opening 3 located at the intersection of the straight line L1 and the other straight line L2. By arranging the three openings 3 in this way and determining the bonding gaps at three locations, it is possible to grasp the tendency of variation in the bonding state of the substrates 11 and 12 to a minimum. Therefore, it is preferable to provide at least three openings 3 in the adhesive layer 2. However, the present invention is not limited to this configuration, and the openings 3 may be arranged such that the straight line L connecting the multiple openings 3 is parallel to the long side of the planar shape of the substrate assembly 1, as shown in Fig. 4(B). Alternatively, the openings 3 may be arranged such that the straight line L connecting the multiple openings 3 is parallel to the short side of the planar shape of the substrate assembly 1, as shown in Fig. 4(C). A configuration in which the multiple openings 3 are arranged in a line along any one side of the planar shape of the substrate assembly 1 in this manner is effective in understanding the variation in the bonding gap G and, ultimately, the variation in the bonding state of the substrates 11, 12.

[0016] It is also preferable to arrange the openings 3 so that the straight line connecting the openings 3 passes through the center position 4 of the planar shape of the substrate assembly 1. In the example shown in FIG. 4(D), similarly to the examples shown in FIGS. 1 to 4(A), the straight line L1 connecting the openings 3 is parallel to the long side of the planar shape of the substrate assembly 1, and the straight line L2 connecting the other openings 3 is parallel to the short side of the planar shape of the substrate assembly 1. Furthermore, these two straight lines L1 and L2 pass through the center position 4 of the planar shape of the substrate assembly 1, and cross each other at right angles to each other. In the example shown in FIG. 4(E), the straight line L connecting the openings 3 is parallel to the long side of the planar shape of the substrate assembly 1 and passes through the center position 4 of the planar shape of the substrate assembly 1. In the example shown in FIG. 4(F), the straight line L connecting the openings 3 is parallel to the short side of the planar shape of the substrate assembly 1 and passes through the center position 4 of the planar shape of the substrate assembly 1. 4(D) to 4(F), it is easy to grasp the variation in the bonding gap G and, in turn, the variation in the bonded state of the substrates 11 and 12. In particular, as shown in Fig. 4(D), in a configuration in which the multiple openings 3 form two straight lines L1 and L2 in a cross shape and both straight lines L pass through the center position 4 of the planar shape of the bonded substrate body 1, it is easy to grasp the variation in the bonding gap G and, in turn, the variation in the bonded state of the substrates 11 and 12.

[0017] As shown in Figs. 5(A) to 5(D), it is also preferable to arrange the openings 3 so that the straight lines connecting the openings 3 are not parallel to each side of the substrate assembly 1 but pass through the center position 4 of the planar shape of the substrate assembly 1. In the example shown in Fig. 5(A), the openings 3 are arranged so that the straight lines L1 and L2 connecting the openings 3 are two diagonal lines passing through the center position 4 of the planar shape of the substrate assembly 1. In the example shown in Fig. 5(B), the openings 3 are arranged so that the straight line L connecting the openings 3 is one of two diagonal lines passing through the center position of the substrate assembly 1. In these configurations, the variation in the bonding gap G can be known along the diagonal lines of the planar shape of the substrate assembly 1, and the bonding state of the substrates 11 and 12 can be easily understood. However, as shown in Figs. 5(C) and 5(D), even if the straight lines L, L1, and L2 connecting the openings 3 are not diagonal lines but are straight lines passing through the center position 4 of the planar shape of the substrate assembly 1, it is effective for understanding the bonding state of the substrates 11 and 12. Furthermore, as shown in Figs. 5(E) and 5(F), even if the straight line L connecting the multiple openings 3 is not a diagonal line and does not pass through the center position 4 of the planar shape of the substrate assembly 1, the bonding state of the substrates 11 and 12 can be grasped. In this case, a configuration in which at least three openings 3 (more specifically, the center points of the planar shapes of the openings 3) of the multiple openings are arranged on a straight line, as shown in Fig. 5(E) and the like, is preferable. Also, a configuration in which a straight line L1 connecting some openings 3 (more specifically, the center points of the planar shapes of the openings 3) and a straight line L2 connecting other openings 3 (more specifically, the center points of the planar shapes of the openings 3) are perpendicular to each other, as shown in Fig. 5(F) and the like, is preferable. That is, a configuration in which some sets of openings 3 of the multiple openings 3 are arranged on a straight line, and other sets including other openings 3 of the multiple openings 3 are arranged on other straight lines perpendicular to the straight line is also preferable. With these configurations, the bonding state of the substrates 11 and 12 can be grasped accurately and efficiently.

[0018] A method for manufacturing the substrate assembly 1, which uses the openings 3 to control the bonding gap G during the bonding process of the substrates 11 and 12, will be described. A pair of substrates 11 and 12 is prepared, and an adhesive layer 2 is formed on one substrate 11 as described above, and patterned so that an adhesive-free region (openings 3) is provided in the adhesive layer 2 (see Figs. 3(A1) to 3(B2)). The materials of the substrates 11 and 12 and the adhesive layer 2, and the thickness of the adhesive layer 2, may be the same as those in the above-mentioned example. The adhesive layer 2 can be patterned by a photolithography method, such as a method of applying a photosensitive adhesive, exposing it to light, and developing it, or a method of partially removing it by etching using a resist mask after film formation. Alternatively, the adhesive layer 2 having the openings 3 can be formed by an on-demand film formation method, such as a screen printing method or a dispensing method of a viscoelastic adhesive. The preferred number and arrangement of the openings 3 are as described above. When the adhesive layer 2 is sandwiched between the substrates 11 and 12 in a later process, the adhesive layer 2 is crushed, and the opening 3 is deformed so that the planar shape of the opening 3 becomes smaller. This tendency is greater as the adhesive layer 2 becomes thicker. Therefore, the thickness of the adhesive layer 2 and the size of the opening 3 are set in consideration of the bonding conditions and the like so that the opening 3 remains after the substrates 11 and 12 are bonded, without disappearing. The area and height (thickness of the adhesive layer 2) of the planar shape of the opening 3 before the substrates 11 and 12 are bonded are obtained in advance. Then, as shown in Figs. 3(C1) and 3(C2), the pair of substrates 11 and 12 are aligned, and the adhesive layer 2 formed on one substrate 11 is overlapped with the other substrate 12, so that the pair of substrates 11 and 12 are laminated with the adhesive layer 2 interposed therebetween. Then, the pair of substrates 11 and 12 overlapping with the adhesive layer 2 are pressurized while correcting the position as necessary, and the pair of substrates 11 and 12 are bonded to each other with the adhesive layer 2. In this manner, a substrate assembly 1 including an adhesive layer 2 having an opening 3 is produced.

[0019] In this way, by observing the planar shape of the opening 3 during the bonding of the substrates 11 and 12, it is possible to control the bonding so as to realize a good bonding state. For example, by monitoring the area of ​​a plurality of openings 3 during bonding of the substrates 11 and 12, it is possible to obtain the bonding gap (i.e., the thickness of the adhesive layer 2) at the position of each opening 3 at that time. Then, the pressure conditions of the substrates 11 and 12 can be controlled so that the substrates 11 and 12 are brought closer to each other at positions where the bonding gap is large, and the substrates 11 and 12 are brought not so close to each other at positions where the bonding gap is small. By controlling in this way, it is possible to suppress excessive pressure so as to reduce the overflow of excess adhesive, and to minimize the variation in the bonding gap when localized pressure failure occurs due to foreign matter, thereby realizing a good bonding state. Such control is performed, for example, by using an automatic system equipped with a camera (e.g., an infrared camera) that captures the planar shape of the opening 3, software that determines the area from the image captured by the camera, and a bonding device that controls the bonding conditions based on the analysis results by the software. Then, by gradually applying pressure to the adhesive layer 2 using the substrates 11 and 12 and terminating the application of pressure when the planar shape of the opening 3 reaches a preset area, it is possible to manufacture a substrate assembly 1 in which the bonding gap G is appropriately controlled.

[0020] In the examples shown in Figs. 1 to 5, the planar shape of the opening 3 is circular, but is not limited thereto. As shown in Fig. 6(A), a configuration may be made in which a plurality of openings 3 having a rectangular planar shape are provided in the adhesive layer 2. As shown in Fig. 6(B), a configuration may be made in which a plurality of openings 3 having an oval planar shape are provided in the adhesive layer 2. As shown in Fig. 6(C), a configuration may be made in which a plurality of openings 3 having a triangular planar shape are provided in the adhesive layer 2. In addition, although not shown, a configuration may be made in which a plurality of openings 3 having a pentagonal or higher polygonal planar shape are provided in the adhesive layer 2. However, in consideration of the ease of measuring the area, openings 3 having a simple planar shape with good visibility, such as a circle or a square, are preferable. Furthermore, in order to maintain a high bonding strength, a circular opening 3 is particularly preferable because it allows one bonding gap to be obtained in a small area compared to a polygon. Furthermore, opening 3 having a circular planar shape is preferable because it is less likely to cause anisotropy in the bonding strength in a plane parallel to the main surfaces of substrates 11 and 12, and therefore the effect of providing opening 3 on the bonding strength can be kept small.

[0021] The number and arrangement of the openings 3 are not limited, even if the planar shape of the openings 3 is circular as shown in Figs. 1 to 5, or if the planar shape of the openings 3 is other than circular as shown in Fig. 6. However, it is more preferable to arrange the multiple openings 3 as described above. That is, it is more preferable to arrange at least two of the multiple openings 3 in parallel to one side of the outer shape of the substrate assembly 1 as shown in Figs. 1 to 4. It is also preferable to arrange at least two of the multiple openings 3 on a straight line passing through the center position 4 of the planar shape of the substrate assembly 1 as shown in Figs. 4(D) to 5(D). It is also preferable to arrange at least three openings 3 on a straight line as shown in Figs. 4(B), 4(C), 4(E), 4(F), 5(B), 5(C), and 5(E). The configurations shown in Figs. 1 to 4(A), 4(D), and 5(F) are also preferable. In this configuration, a set of some openings among the multiple openings 3 is arranged on a straight line L1, and another set including the other openings among the multiple openings is arranged on another straight line L2 perpendicular to the above-mentioned straight line L1. In these configurations, the variation in the bonding gap G and the bonding state can be intuitively and efficiently grasped, and therefore it is easy to control the pressure conditions during bonding of the substrates 11 and 12, and the mounting conditions and device operating conditions after bonding. From the viewpoint of obtaining the variation in the bonding gap with high precision, the more the number of openings 3, the better, but in order to maintain high bonding strength, it is preferable that the number of openings is three or less.

[0022] The substrate assembly 1 shown in Figures 1 to 5 may be in the form of a chip to be incorporated into a device such as a liquid ejection head, or may be in the form of a large-area wafer to be cut into a plurality of chips after manufacture, as shown in Figure 7. In Figure 7, a plurality of openings 3 provided in the adhesive layer 2 and a cutting line C along which the adhesive layer 2 is cut into a plurality of chips are indicated by dashed lines. For ease of viewing, each opening 3 is illustrated larger than it actually is. In the example shown in Figure 7, the openings 3 are provided at positions that avoid the portions that will be cut into chips.

[0023] In each of the above-mentioned examples, the planar shapes of the substrates 11 and 12 are the same, so that the outer shape of the substrate assembly 1 is the same as that of each of the substrates 11 and 12. However, although not shown, the substrate assembly 1 may be formed by combining the substrates 11 and 12 having different planar shapes. That is, the substrates 11 and 12 bonded via the adhesive layer 2 may have different dimensions and shapes. In that case, it is preferable that the multiple openings 3 are arranged parallel to one side of the outer shape of at least one of the pair of substrates 11 and 12. It is also preferable that the multiple openings 3 are arranged on a straight line passing through the center position 4 of the planar shape of at least one of the pair of substrates 11 and 12.

[0024] [Second embodiment] Next, a second embodiment of the present invention will be described. Figures 8(A1), 8(B1), and 8(C1) are cross-sectional views showing the bonding process of the substrates 11 and 12 in this embodiment in order, and Figures 8(A2), 8(B2), and 8(C2) are plan views showing the bonding process in order. In this embodiment, as shown in Figures 8(C1) and 8(C2), the bonding gap (thickness of the adhesive layer 2) is larger in the region 6 including the opening 3 than in other parts. In this embodiment, as shown in Figures 8(A1) and 8(A2), a recess 5 is formed in one of the substrates (substrate 11 in the example shown in Figure 8) at a position facing the opening 3 after the adhesive layer 2 is formed. Then, as shown in Figures 8(B1) and 8(B2), the adhesive layer 2 is formed on the substrate 11 in the same manner as in the first embodiment, and the opening 3 is formed in the adhesive layer 2. In a plan view, the opening 3 is provided in a portion facing the recess 5 of the adhesive layer 2. The recess 5 of the substrate 11 and the opening 3 of the adhesive layer 2 have the same planar shape, are arranged at positions where they completely overlap, and the recess 5 and the opening 3 are connected to form one long hollow tube. Then, as shown in Figs. 8(C1) and 8(C2), another substrate 12 is placed on the adhesive layer 2 on the substrate 11, and the adhesive layer 2 is sandwiched between the pair of substrates 11 and 12 and pressurized. At this time, a part of the pressurized adhesive flows toward the inside of the opening 3 and enters the recess so as to fill the recess 5. As a result, the opening 3 in the adhesive layer 2 shown in Figs. 8(C1) and 8(C2) has a smaller diameter than that of the adhesive layer 2 at the time of film formation shown in Figs. 8(B1) and 8(B2), and is longer than that of the opening 3 in the first embodiment. The area of ​​the planar shape of this opening 3 is measured to determine the bonding gap. Since the depth of recess 5 in substrate 11 is known in advance, the junction gap in region 6 including opening 3 and the junction gap in positions other than region 6 can both be easily determined.

[0025] When forming the opening 3 in the adhesive layer 2, it is necessary to pattern the adhesive formed on the substrate 11. In this embodiment, since the substrate 11 is provided with the recess 5, the adhesive can be selectively patterned by contact transfer such as roll transfer or film transfer without attaching the adhesive to the bottom surface of the recess 5. That is, the adhesive can be easily patterned without using a photolithography process. However, if the recess 5 of the substrate 11 is too deep, the adhesive may not reach the bottom surface of the recess 5 when the substrates 11 and 12 are joined, and the area of ​​the planar shape of the opening 3 may not correspond to the joining gap. In that case, the opening 3 does not function sufficiently as a means for determining the joining gap. Therefore, it is preferable to suppress the depth of the recess 5 of the substrate 11 to about twice or less the thickness of the adhesive layer 2 formed on the substrate 11. Note that, except for the matters described above, the substrate assembly 1 of this embodiment and its manufacturing method are the same as those of the first embodiment, and therefore illustrations and descriptions are omitted.

[0026] [Third embodiment] Next, a third embodiment of the present invention will be described. Figures 9(A1), 9(B1), and 9(C1) are cross-sectional views showing the bonding process of substrates 11 and 12 of this embodiment in sequence, and Figures 9(A2), 9(B2), and 9(C2) are plan views showing the bonding process in sequence. Figure 9 shows an example of a configuration in which an opening 3 having a circular planar shape and an opening 3 having a rectangular planar shape are present in an adhesive layer 2, but the configuration is not limited to this, and the planar shape of the opening 3 can be set arbitrarily.

[0027] The bonding strength of the substrates 11 and 12 in the substrate assembly 1 decreases at the position of the opening 3. Therefore, it is preferable to reduce the area of ​​the opening 3 to prevent the bonding strength from decreasing too much. Therefore, in this embodiment, an isolated adhesive layer 7 that is discontinuous with the adhesive layer 2 outside the opening 3 is provided in the opening to increase the bonding area and suppress the decrease in bonding strength. In this embodiment, the bonding gap G can be obtained by measuring the volume and area of ​​the isolated adhesive layer 7. Specifically, the bonding gap G is calculated by the following formula: [bonding gap G after bonding of the substrates 11 and 12 (film thickness of the adhesive layer 2 after bonding)] = [volume of the isolated adhesive layer 7 before bonding] ÷ [area of ​​the planar shape of the isolated adhesive layer 7 after bonding]. Similarly, the bonding gap G at that time can be obtained by measuring the area of ​​the planar shape of the isolated adhesive layer 7 during the bonding process of the substrates 11 and 12. That is, the bonding gap G is calculated by the formula: [bonding gap G at the time of area measurement (thickness of the adhesive layer 2 at the time of area measurement)] = [volume of the isolated adhesive layer 7 before bonding the pair of substrates] ÷ [area of ​​the planar shape of the isolated adhesive layer 7 at the time of area measurement]. From the viewpoint of the bonding area and bonding strength, it is preferable that the planar shape of the isolated adhesive layer 7 is similar to the opening 3 and is a reduced shape of the opening 3 at the same time. For example, if the planar shape of the opening 3 is a square and the planar shape of the isolated adhesive layer 7 is a square smaller than the opening 3, the loss of the bonding area due to the opening 3 can be reduced, and the decrease in bonding strength can be suppressed to a small extent. In reality, since the adhesive layer 2 is crushed when the substrates 11 and 12 are bonded, the planar shape of the opening 3 is somewhat distorted from the patterned shape of the adhesive, so it is difficult to make the isolated adhesive layer 7 a completely reduced shape of the opening 3, and the reduction ratio may vary by about ± several tens of percent. In this embodiment, it is also possible to obtain the bonding gap by measuring the area inside the opening 3 as if the isolated adhesive layer 7 does not exist, as in the first and second embodiments. Even in this case, by providing the isolated adhesive layer 7, it is possible to minimize the decrease in bonding strength at the position of the opening 3. Note that, apart from the points described above, the substrate assembly 1 of this embodiment and the manufacturing method thereof are similar to those of the first embodiment, and therefore illustrations and descriptions thereof will be omitted.

[0028] [Fourth embodiment] Next, a fourth embodiment of the present invention will be described. Figures 10(A1), 10(B1), and 10(C1) are cross-sectional views showing the bonding process of the substrates 11 and 12 of this embodiment in sequence, and Figures 10(A2), 10(B2), and 10(C2) are plan views showing the bonding process in sequence. In Figure 10, a configuration is illustrated in which an opening 3 having a circular planar shape and an opening 3 having a rectangular planar shape are present in the adhesive layer 2, but the configuration is not limited to such a configuration, and the planar shape of the opening 3 can be set arbitrarily. In this embodiment, an isolated adhesive layer 7 is provided in the opening 3 as in the third embodiment, and a recess 5 is provided in the lower substrate 11 as in the second embodiment, and a support portion 8 supporting the isolated adhesive layer 7 is provided inside the recess 5. This recess 5 functions as an adhesive reservoir (container) so that the adhesive pushing from around the isolated adhesive layer 7 does not come into contact with the isolated adhesive layer 7 when the substrates 11 and 12 are bonded. Thereby, the independence of the isolated adhesive layer 7 can be maintained, and the accuracy of measuring the area of ​​the planar shape to obtain the bonding gap G can be kept high, and the loss of the bonding area can be reduced to suppress the decrease in bonding strength. The recesses 5 may be formed continuously so as to surround the isolated adhesive layer 7, or a plurality of discontinuous recesses 5 may be provided around one isolated adhesive layer 7 as illustrated on the right side of each of Figs. 10(A1) to 10(C2). When a plurality of discontinuous recesses 5 are provided around one isolated adhesive layer 7, the portion surrounded by the plurality of recesses 5 becomes the support portion 8 that supports the isolated adhesive layer 7. Such a plurality of discontinuous recesses 5 also function as a reservoir of adhesive. Note that, other than the matters described above, the substrate assembly 1 of this embodiment and the manufacturing method thereof are the same as those of the first embodiment, and therefore illustration and description are omitted. EXAMPLES

[0029] [Example 1] Fig. 11(A) is a schematic perspective view showing a main part of a liquid discharge head including a substrate assembly 1 according to a first embodiment of the present invention, Fig. 11(B) is a cross-sectional view taken along line BB in Fig. 11(A), and Fig. 11(C) is a cross-sectional view taken along line CC in Fig. 11(A). Fig. 12 is a diagram showing some steps of a method for manufacturing a liquid discharge head in order. Figs. 12(A1), 12(B1), 12(C1), and 12(D1) are cross-sectional views taken along line BB in Fig. 11(A), and Figs. 12(A2), 12(B2), 12(C2), and 12(D2) are cross-sectional views taken along line CC in Fig. 11(A). The liquid discharge head shown in Fig. 11 has a substrate assembly 1, and a liquid storage section 17 and an electric wiring member 18, which are shown in a schematic manner. The first substrate 11 of the substrate assembly 1 of this embodiment is a Si substrate having a thickness of 600 μm and a plurality of supply paths 13 and energy generating elements 14 (e.g., pressure generating elements or heat generating elements). The second substrate 12 is a Si substrate having a plurality of discharge ports 15. These substrates 11, 12 are laminated via an adhesive layer 2, and are bonded by applying pressure so that the thickness of the adhesive layer 2 after bonding is about 0.5 μm. The substrate 12 and the adhesive layer 2 are formed with a flow path including a pressure chamber 16 that communicates the supply path 13 and the discharge port 15 in the bonded state of the substrates 11, 12. In addition, openings 3a, 3b, and 3c, which are through holes having a circular planar shape, are provided near three corners of the adhesive layer 2, and isolated adhesive layers 7a, 7b, and 7c having a circular planar shape are provided inside each of the openings 3a, 3b, and 3c. The liquid storage portion 17 is connected to the supply path 13, and the electric wiring member 18 is connected to the energy generating element 14.

[0030] The planar shape of the isolated adhesive layers 7a, 7b, and 7c before bonding the substrates 11 and 12 was a circle with a diameter of 50 μm, and the thickness (height) of the isolated adhesive layer 7 before bonding was 1 μm. After bonding the substrates 11 and 12 to manufacture the substrate assembly 1, the planar areas of the three isolated adhesive layers 7a, 7b, and 7c were observed with an infrared microscope to determine the areas. As a result, the planar areas of the two isolated adhesive layers 7a and 7b were approximately 15,700 μm 2 On the other hand, the planar area of ​​one isolated adhesive layer 7c was 8700 μm 2From the volume of the isolated adhesive layer 7 before bonding the substrates 11 and 12 and the area of ​​the planar shape of the isolated adhesive layer 7 after bonding the substrates 11 and 12 (after manufacturing the substrate assembly 1), the bonding gaps (the distance between the substrates 11 and 12) at the positions of the openings 3a, 3b, and 3c were calculated. As a result, the bonding gap at the positions of the two openings 3a and 3b was calculated to be about 0.5 μm, and the bonding gap at the position of the opening 3c was calculated to be about 0.9 μm. Then, when the substrate assembly 1 was inspected in detail, it was found that a foreign object was sandwiched around the opening 3c and the isolated adhesive layer 7c, which caused the bonding gap to become large. In this way, the bonding gap of the substrate assembly 1 could be grasped by using the openings 3a, 3b, and 3c and the isolated adhesive layers 7a, 7b, and 7c. A liquid storage portion 17, an electric wiring member 18, and the like were connected to the substrate assembly 1 to configure a liquid ejection head (see FIG. 11). When a liquid ejection test was performed on this liquid ejection head under certain driving conditions, it was confirmed that the print density from the ejection ports 15 around the opening 3c and the isolated adhesive layer 7c was high and the ejection amount was larger than that of the other ejection ports 15. From this test, it is assumed that the variation in the joint gap led to the variation in the ejection amount. Therefore, the driving conditions of the energy generating element 14 were set so as to reduce the print impact amount of the ejection ports 15 around the opening 3c and the isolated adhesive layer 7c, where the printing was confirmed to be high, and the liquid ejection test was performed again, and the difference in the print density was mitigated. That is, in this embodiment, the variation in the joint gap was obtained using the openings 3a, 3b, and 3c and the isolated adhesive layers 7a, 7b, and 7c, and the driving conditions of the energy generating element 14 were appropriately controlled based on the obtained variation. It was found that the effect of the variation in the joint gap on the print quality of the liquid ejection head was suppressed to a small value, and relatively good print quality could be maintained.

[0031] [Example 2] In Example 2, a liquid ejection head (see FIG. 11) having a similar configuration to Example 1 was manufactured, and the variation in the bonding gap was obtained during the bonding process of the substrates 11 and 12 using the openings 3a, 3b, and 3c and the isolated adhesive layers 7a, 7b, and 7c. Specifically, as shown in FIGS. 12(A1) and 12(A2), a first substrate 11 was manufactured by forming a supply path 13, which is a through hole, by dry etching on a Si substrate having an energy generating element 14 and a driving circuit (not shown). In addition, as shown in FIGS. 12(B1) and 12(B2), a recessed portion that becomes a part of a flow path including a pressure chamber 16 was formed by dry etching on another Si substrate, and a discharge port 15, which is a through hole communicating with the recessed portion, was formed to manufacture a second substrate 12. Then, as shown in FIGS. 12(C1) and 12(C2), an adhesive containing a solvent made of an organic resin was applied to the second substrate 12 by screen printing to form an adhesive layer 2. A plurality of openings (areas where no adhesive exists) 3a, 3b, 3c are formed in the adhesive layer 2, and isolated adhesive layers 7a, 7b, 7c are provided inside each of the openings 3a, 3b, 3c. Each of the openings 3a, 3b, 3c has a circular shape with a diameter of 600 μm in plan view, and is a through hole penetrating the adhesive layer 2. Each of the isolated adhesive layers 7a, 7b, 7c has a circular shape with a diameter of 50 μm in plan view, and is a cylindrical shape with a height (thickness) of 1 μm. Then, as shown in FIG. 12(D1) and 12(D2), the first substrate 11 is superimposed on the adhesive layer 2 formed on the second substrate 12. At this time, the laminate of the substrates 11, 12 and the adhesive layer 2 is pressed along the stacking direction while the area of ​​each of the isolated adhesive layers 7a, 7b, 7c is measured by imaging the area of ​​the planar shape by an infrared camera. In the design, it was assumed that a pressure of 2 kN would be applied to set the bonding gap G between the substrates 11 and 12 to about 0.6 μm. In contrast, the planar area of ​​the isolated adhesive layers 7a, 7b, and 7c actually measured in this embodiment was 11214 μm. 2 The pressure was about 1000 psi, and the joint gap G was estimated to be about 0.7 μm. This was thought to be because it was difficult to apply sufficient pressure due to the presence of foreign matter. Therefore, the pressure was gradually increased to reduce the joint gap to 0.6 μm. When the pressure reached about 3 kN, the planar area of ​​the isolated adhesive layers 7a, 7b, and 7c was 13083 μm. 2Since it was estimated that the bonding gap G reached the desired level of approximately 0.6 μm, the application of pressure was stopped and the bonding of the substrates 11 and 12 was completed. In this manner, in the course of the bonding process of the substrates 11 and 12, pressure was applied while monitoring the bonding gap using the openings 3a, 3b, and 3c and the isolated adhesive layers 7a, 7b, and 7c, so that the substrate bonded body 1 having the desired bonding gap and bonding strength could be easily manufactured.

[0032] Disclosure of embodiments and examples of the present invention includes the following configurations and methods. (Configuration 1) A substrate assembly comprising at least a pair of substrates stacked together via an adhesive layer, the adhesive layer having a plurality of openings penetrating the adhesive layer in the stacking direction of the pair of substrates, and at least two of the plurality of openings being arranged parallel to one side of the outer shape of at least one of the pair of substrates. (Configuration 2) A substrate assembly comprising at least a pair of substrates stacked together via an adhesive layer, the adhesive layer having a plurality of openings penetrating the adhesive layer in the stacking direction of the pair of substrates, at least two of the plurality of openings being arranged side by side on a straight line passing through a center position of the planar shape of at least one of the pair of substrates. (Configuration 3) A substrate assembly comprising at least a pair of substrates stacked together via an adhesive layer, the adhesive layer having a plurality of openings penetrating the adhesive layer in the stacking direction of the pair of substrates, and at least three of the plurality of openings being arranged side by side on a straight line. (Configuration 4) The substrate assembly according to configuration 3, wherein the straight line on which the at least three openings are arranged passes through a center position of a planar shape of at least one of the pair of substrates. (Configuration 5) 5. The substrate assembly of any one of configurations 2 to 4, wherein the straight line on which the openings are arranged is parallel to any one side of an outer shape of at least one of the pair of substrates. (Configuration 6) A substrate assembly comprising at least a pair of substrates laminated together via an adhesive layer, the adhesive layer having a plurality of openings penetrating the adhesive layer in the stacking direction of the pair of substrates, a set of some of the plurality of openings being arranged side by side on a straight line, and another set including other openings of the plurality of openings being arranged side by side on another straight line perpendicular to the straight line. (Configuration 7) The substrate assembly according to configuration 6, wherein the plurality of openings includes an opening located at an intersection of the straight line and the other straight line. (Configuration 8) 8. The substrate assembly according to claim 6 or 7, wherein at least one of the straight line and the other straight line is parallel to any one side of an outer shape of at least one of the pair of substrates. (Configuration 9) 9. The substrate assembly of any one of configurations 6 to 8, wherein at least one of the straight line and the other straight line passes through a center position of a planar shape of at least one of the pair of substrates. (Configuration 10) The planar area of ​​the opening is 100 μm 2 More than 100000μm 2 10. The substrate assembly according to any one of claims 1 to 9, wherein: (Configuration 11) 11. The substrate assembly of any one of configurations 1 to 10, wherein the number of the openings is three or less. (Configuration 12) 12. The substrate assembly according to any one of configurations 1 to 11, wherein the opening has a circular planar shape. (Configuration 13) 13. The substrate assembly according to any one of configurations 1 to 12, wherein an isolated adhesive layer is provided within the opening and is discontinuous with the adhesive layer located outside the opening. (Configuration 14) 14. The substrate assembly according to claim 13, wherein the planar shape of the isolated adhesive layer is a reduced shape of the planar shape of the opening. (Configuration 15) 13. The substrate assembly of claim 1, wherein a recess is formed on a surface of one of the pair of substrates facing the other substrate, a portion of the adhesive layer extends into the recess, and the opening is provided in a portion of the adhesive layer facing the recess when viewed from a direction perpendicular to the main surfaces of the pair of substrates. (Configuration 16) 16. The substrate assembly of claim 15, wherein an isolated adhesive layer is provided within the opening and is discontinuous with the adhesive layer located outside the opening. (Configuration 17) 17. The substrate assembly of claim 16, wherein the one substrate has a support portion within the recess that supports the isolated adhesive layer. (Configuration 18) A liquid ejection head comprising: a substrate assembly according to any one of configurations 1 to 17, in which a supply path, a pressure chamber, an energy generating element, and an ejection port are provided in the pair of substrates; and a liquid storage section and an electrical wiring member connected to the substrate assembly. (Method 1) A method for manufacturing a substrate bonded body in which a pair of substrates are bonded via an adhesive layer, comprising the steps of: forming an adhesive layer on one of the pair of substrates; overlapping the other substrate on the adhesive layer formed on the one substrate; and applying pressure to the pair of substrates overlapping with each other via the adhesive layer to bond the pair of substrates to each other with the adhesive layer; In the step of forming the adhesive layer, a plurality of openings are provided in the adhesive layer, the openings penetrating the adhesive layer in a stacking direction of the pair of substrates; A method for producing a substrate bonded body, comprising the step of: thinning the adhesive layer in the step of bonding the pair of substrates to each other. (Method 2) A method for manufacturing a substrate bonded body according to method 1, in which the distance between the pair of substrates is determined based on a planar area of ​​the opening in the adhesive layer before the step of bonding the pair of substrates to each other, which is known in advance, and an area of ​​the planar shape of the opening determined after the step of bonding the pair of substrates to each other. (Method 3) The method for manufacturing a substrate bonded body according to Method 2, wherein the distance between the pair of substrates is calculated from the formula: [area of ​​the planar shape of the opening after bonding of the pair of substrates ÷ area of ​​the planar shape of the opening before bonding] × [thickness of the adhesive layer before bonding]. (Method 4) determining an area of ​​a planar shape of the opening of the adhesive layer during the step of bonding the pair of substrates to each other; The method for manufacturing a substrate bonded body described in Method 1, further comprising determining a distance between the pair of substrates based on a planar area of ​​the opening in the adhesive layer before the step of bonding the pair of substrates to each other, which is known in advance, and a planar area of ​​the opening determined during the step of bonding the pair of substrates to each other, and controlling conditions for pressing the pair of substrates based on the distance. (Method 5) The method for manufacturing a substrate bonded body according to Method 4, wherein the distance between the pair of substrates is calculated from the formula: [area of ​​the planar shape of the opening at the time of area measurement ÷ area of ​​the planar shape of the opening before bonding of the pair of substrates] × [thickness of the adhesive layer at the time of area measurement]. (Method 6) providing an isolated adhesive layer within the opening, the isolated adhesive layer being discontinuous with the adhesive layer located outside the opening; A method for manufacturing a substrate bonded body according to method 1, in which the distance between the pair of substrates is calculated based on a volume of the isolated adhesive layer before the step of bonding the pair of substrates to each other, which is known in advance, and an area of ​​the planar shape of the isolated adhesive layer calculated after the step of bonding the pair of substrates to each other. (Method 7) The method for manufacturing a substrate bonded body according to Method 6, wherein the distance between the pair of substrates is calculated from the formula: [volume of the isolated adhesive layer before bonding of the pair of substrates]÷[area of ​​the planar shape of the isolated adhesive layer after bonding]. (Method 8) providing an isolated adhesive layer within the opening, the isolated adhesive layer being discontinuous with the adhesive layer located outside the opening; determining an area of ​​a planar shape of the isolated adhesive layer during the step of bonding the pair of substrates to each other; A method for manufacturing a substrate bonded body according to method 1, comprising determining a distance between the pair of substrates based on a volume of the isolated adhesive layer before the step of bonding the pair of substrates to each other, which is known in advance, and an area of ​​a planar shape of the isolated adhesive layer determined during the step of bonding the pair of substrates to each other, and controlling conditions for pressing the pair of substrates based on the distance. (Method 9) The method for manufacturing a substrate bonded body according to Method 8, wherein the distance between the pair of substrates is calculated from the formula: [volume of the isolated adhesive layer before bonding the pair of substrates]÷[area of ​​the planar shape of the isolated adhesive layer at the time of area measurement]. (Method 10) The method for manufacturing a substrate assembly according to any one of Methods 1 to 9, wherein at least two of the plurality of openings are arranged side by side along any one edge of an outer shape of at least one of the pair of substrates. (Method 11) 11. The method for manufacturing a substrate assembly according to any one of Methods 1 to 10, wherein at least two of the plurality of openings are arranged side by side on a straight line passing through a center position of a planar shape of at least one of the pair of substrates. (Method 12) 12. The method for producing a substrate assembly according to any one of methods 1 to 11, wherein at least three openings of the plurality of openings are arranged in a line. (Method 13) 13. The method for manufacturing a substrate bonded body according to any one of Methods 1 to 12, wherein some sets of the plurality of openings are arranged side by side on a straight line, and other sets including other openings of the plurality of openings are arranged side by side on another straight line perpendicular to the straight line. (Method 14) A method for manufacturing a liquid ejection head, comprising: each step of the method for manufacturing a substrate assembly according to any one of methods 1 to 13; and a step of connecting a liquid storage section and an electrical wiring member to the substrate assembly. [Explanation of symbols]

[0033] 1 Substrate assembly 2 Adhesive layer 3 Opening 11,12 Circuit Board

Claims

1. A substrate assembly comprising at least a pair of substrates stacked together via an adhesive layer, the adhesive layer having a plurality of openings penetrating the adhesive layer in the stacking direction of the pair of substrates, and at least two of the plurality of openings being arranged parallel to one side of the outer shape of at least one of the pair of substrates.

2. A substrate assembly comprising at least a pair of substrates stacked together via an adhesive layer, the adhesive layer having a plurality of openings penetrating the adhesive layer in the stacking direction of the pair of substrates, and at least two of the plurality of openings being arranged side by side on a straight line passing through the center position of the planar shape of at least one of the pair of substrates.

3. A substrate assembly comprising at least a pair of substrates stacked together via an adhesive layer, the adhesive layer having a plurality of openings penetrating the adhesive layer in the stacking direction of the pair of substrates, and at least three of the plurality of openings being arranged side by side in a straight line.

4. The substrate assembly according to claim 3 , wherein the straight line on which the at least three openings are arranged passes through a center position of a planar shape of at least one of the pair of substrates.

5. 4. The substrate assembly according to claim 2, wherein the straight line on which the openings are arranged is parallel to any one side of an outer shape of at least one of the pair of substrates.

6. A substrate assembly comprising at least a pair of substrates stacked together via an adhesive layer, the adhesive layer having a plurality of openings penetrating the adhesive layer in the stacking direction of the pair of substrates, a set of some of the plurality of openings being arranged side by side on a straight line, and another set of the plurality of openings including other openings being arranged side by side on another straight line perpendicular to the straight line.

7. The substrate assembly according to claim 6 , wherein the plurality of openings includes an opening located at an intersection of the straight line and the other straight line.

8. 8. The substrate assembly according to claim 6, wherein at least one of the straight line and the other straight line is parallel to any one side of an outer shape of at least one of the pair of substrates.

9. 8. The substrate assembly according to claim 6, wherein at least one of the straight line and the other straight line passes through a center position of a planar shape of at least one of the pair of substrates.

10. The planar area of ​​the opening is 100 μm 2 More than 100000μm 2 7. The substrate assembly according to claim 1, wherein:

11. 7. The substrate assembly according to claim 1, wherein the number of the openings is three or less.

12. 7. The substrate assembly according to claim 1, wherein the opening has a circular planar shape.

13. 7. The substrate assembly according to claim 1, wherein an isolated adhesive layer is provided within the opening, the isolated adhesive layer being discontinuous with the adhesive layer located outside the opening.

14. The substrate assembly according to claim 13 , wherein the planar shape of the isolated adhesive layer is a reduced shape of the planar shape of the opening.

15. 7. The substrate assembly according to claim 1, wherein a recess is formed on a surface of one of the pair of substrates facing the other substrate, a portion of the adhesive layer extends into the recess, and the opening is provided in a portion of the adhesive layer facing the recess when viewed from a direction perpendicular to the main surfaces of the pair of substrates.

16. 16. The substrate assembly according to claim 15, wherein an isolated adhesive layer is provided within the opening and is discontinuous with the adhesive layer located outside the opening.

17. 17. The substrate assembly according to claim 16, wherein the one substrate has a support portion in the recess that supports the isolated adhesive layer.

18. 10. A liquid ejection head comprising: a substrate assembly according to claim 1, wherein a supply path, a pressure chamber, an energy generating element, and an ejection port are provided on the pair of substrates; and a liquid storage section and an electrical wiring member connected to the substrate assembly.

19. A method for manufacturing a substrate assembly in which a pair of substrates are bonded together via an adhesive layer, comprising the steps of: forming an adhesive layer on one of the pair of substrates; overlaying the other substrate on the adhesive layer formed on the one of the pair of substrates; and pressing the pair of substrates overlapping each other via the adhesive layer to bond the pair of substrates to each other by the adhesive layer; In the step of forming the adhesive layer, a plurality of openings are provided in the adhesive layer in a stacking direction of the pair of substrates, the openings penetrating the adhesive layer; In the step of bonding the pair of substrates together, the adhesive layer is thinned, A method for manufacturing a substrate assembly, characterized in that the distance between the pair of substrates is determined based on a previously known area of ​​the planar shape of the opening in the adhesive layer before the step of bonding the pair of substrates to each other, and an area of ​​the planar shape of the opening determined after the step of bonding the pair of substrates to each other.

20. 20. The method for manufacturing a substrate assembly according to claim 19, wherein the distance between the pair of substrates is calculated from the formula: [area of ​​the planar shape of the opening after bonding the pair of substrates ÷ area of ​​the planar shape of the opening before bonding] × [thickness of the adhesive layer before bonding].

21. determining an area of ​​a planar shape of the opening in the adhesive layer during the step of bonding the pair of substrates to each other; 20. The method for manufacturing a substrate assembly according to claim 19, wherein the distance between the pair of substrates is determined based on a previously known area of ​​a planar shape of the opening in the adhesive layer before the step of bonding the pair of substrates to each other and an area of ​​a planar shape of the opening determined during the step of bonding the pair of substrates to each other, and the conditions for pressing the pair of substrates are controlled based on the distance.

22. 22. The method for manufacturing a substrate assembly according to claim 21, wherein the distance between the pair of substrates is calculated from the formula: [area of ​​the planar shape of the opening at the time of area measurement ÷ area of ​​the planar shape of the opening before bonding the pair of substrates] × [thickness of the adhesive layer at the time of area measurement].

23. providing an isolated adhesive layer within the opening that is discontinuous with the adhesive layer located outside the opening; 20. The method for manufacturing a substrate assembly according to claim 19, wherein the distance between the pair of substrates is calculated based on a volume of the isolated adhesive layer that is known in advance before the step of bonding the pair of substrates to each other and an area of ​​a planar shape of the isolated adhesive layer that is calculated after the step of bonding the pair of substrates to each other.

24. 24. The method for manufacturing a substrate assembly according to claim 23, wherein the distance between the pair of substrates is calculated from the formula: [volume of the isolated adhesive layer before bonding the pair of substrates]÷[area of ​​the planar shape of the isolated adhesive layer after bonding].

25. providing an isolated adhesive layer within the opening that is discontinuous with the adhesive layer located outside the opening; During the step of bonding the pair of substrates to each other, an area of ​​a planar shape of the isolated adhesive layer is determined; 20. The method for manufacturing a substrate bonded body according to claim 19, wherein a distance between the pair of substrates is calculated based on a volume of the isolated adhesive layer before the step of bonding the pair of substrates together, which is known in advance, and an area of ​​a planar shape of the isolated adhesive layer calculated during the step of bonding the pair of substrates together, and conditions for pressing the pair of substrates are controlled based on the distance.

26. 26. The method for manufacturing a substrate assembly according to claim 25, wherein the distance between the pair of substrates is calculated from the formula: [volume of the isolated adhesive layer before bonding the pair of substrates]÷[area of ​​the planar shape of the isolated adhesive layer at the time of area measurement].

27. 27. The method for manufacturing a substrate assembly according to claim 19, wherein at least two of the plurality of openings are arranged side by side along any one side of an outer shape of at least one of the pair of substrates.

28. 27. The method for manufacturing a substrate assembly according to claim 19, wherein at least two of the plurality of openings are arranged side by side on a straight line passing through a center position of a planar shape of at least one of the pair of substrates.

29. The method for manufacturing a substrate assembly according to claim 19 , wherein at least three openings out of the plurality of openings are arranged side by side on a single straight line.

30. 27. The method for manufacturing a substrate assembly according to claim 19, wherein some sets of the plurality of openings are arranged side by side on one straight line, and other sets of the plurality of openings including other openings are arranged side by side on another straight line perpendicular to the straight line.

31. 27. A method for manufacturing a liquid ejection head, comprising: the steps of the method for manufacturing a substrate assembly according to claim 19; and a step of connecting a liquid storage portion and an electric wiring member to the substrate assembly.

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