Substrate joint body and liquid discharge head

Abstract

To provide a substrate joint body and a liquid discharge head that restrict occurrences of air gaps in an adhesive material, while suppressing squeeze-out of the adhesive material into openings of a substrate.SOLUTION: In a substrate joint body, a first substrate 1 and a second substrate 2 are joined via an adhesive material 3. In the substrate joint body: protrusions 4 protruding toward the second substrate 2 are formed on a surface of the first substrate 1 on a side where the adhesive material 3 is caused to adhere; further, the protrusions 4 are arranged so as to surround openings 5; grooves 6 are formed in an upper surface of the protrusion 4; and the grooves 6 extend to an end of the protrusion 4.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present embodiment relates to a substrate assembly and a liquid ejection head. [Background technology]

[0002] A substrate assembly formed by bonding two substrates is used in various electronic devices. For example, it is a liquid ejection head mounted on an inkjet printer or the like. In order to form a liquid flow path having a complex three-dimensional structure, a liquid ejection head may have a substrate assembly in which a substrate having a liquid ejection energy generating element and a liquid flow path structure is bonded to another substrate facing the substrate. When bonding substrates via an adhesive, a method for stably forming the adhesive at the bonding interface is required. For example, Patent Document 1 proposes a flow path member in which a plurality of substrates in which holes constituting the flow path are arranged are laminated via an adhesive layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-190498 A Summary of the Invention [Problem to be solved by the invention]

[0004] A simplified version of Patent Document 1 is shown in Fig. 15. In the flow path member of Patent Document 1, an opening 5 constituting a flow path and a groove 20 not constituting the flow path are arranged on a substrate 1, and a protrusion 4 protruding from the main surface of the substrate on which the groove 20 is arranged is arranged on the edge of the groove 20. The presence of the groove 20 serves the effect of storing excess adhesive and suppressing the adhesive from overflowing into the opening 5. At the same time, the protrusion 4 also serves to define the distance between the substrates (the distance between the substrates) when the substrates are bonded together.

[0005] However, while the structure is expected to have the effect of adhesive overflowing in areas where the adhesive is thicker than necessary, there is a concern that voids will occur in areas where the adhesive is relatively thin because the convex parts 4, which are designed to be higher than the average height of the adhesive, define the intervals. For this reason, there is a concern that these voids 19 will cause leakage of ink flowing through the liquid flow path.

[0006] Next, the factors that promote the adhesive overflow and the occurrence of voids include the film thickness distribution after the adhesive is transferred. The transfer method and the reason for the occurrence of the film thickness distribution will be explained. Figure 8 shows the state of the adhesive transferred onto the second substrate. The second substrate has an opening 5, and the thickness of the adhesive around the opening is uneven. When the film thickness was measured at four points on the four corners of the opening 5 and four points on the sides of the opening, the film thickness was thinner at the four corners than at the sides. This is because a thin film is formed at the four corners where the adhesive moves significantly, while a thick film is formed at the four sides where the adhesive moves less because the adhesive remains in place. Therefore, as the state of the substrates after bonding, there is a concern that voids will occur at the four corners and that the adhesive will overflow into the opening 5 at the sides. Incidentally, the direction of the arrow 10 indicates the transfer direction of the adhesive, and the distribution of the film thickness can be predicted from the transfer direction. Therefore, in order to reliably bond the substrates to each other, it is necessary to avoid the inclusion of air bubbles during bonding and the intrusion of the adhesive into the opening 5, and for this purpose, it is necessary to control the thickness of the adhesive film.

[0007] In view of the above-mentioned problems, the present embodiment has an object to provide a substrate bond and a liquid ejection head that can suppress the adhesive from spilling out into openings in the substrates while also suppressing the occurrence of voids in the adhesive. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a substrate bonded body in which a first substrate and a second substrate are bonded with an adhesive, the first substrate having a protruding portion protruding toward the second substrate on a surface on which the adhesive is applied, the second substrate having an opening, and the protruding portion disposed so as to surround the opening; A groove is formed on the upper surface of the protruding portion, and the groove extends to an end of the protruding portion. Effect of the Invention

[0009] According to the present embodiment, it is possible to provide a substrate bond and a liquid ejection head that can prevent the adhesive from spilling out into the openings in the substrates and also prevent the occurrence of voids in the adhesive. [Brief description of the drawings]

[0010] [Figure 1] 3A and 3B are a perspective view and a cross-sectional view showing a substrate assembly. [Diagram 2] Enlarged view of Figure 1. [Diagram 3] FIG. [Figure 4] FIG. 4 is a cross-sectional view of a protruding portion of a first substrate. [Diagram 5] FIG. 4 is a plan view of a protruding portion of a first substrate. [Figure 6] 3A and 3B are a plan view and a cross-sectional view of a substrate assembly. [Figure 7] FIG. 2 is a perspective view of a first substrate and a second substrate. [Figure 8] 4A and 4B are a plan view and a cross-sectional view of the adhesive transferred onto a second substrate. [Figure 9] 3A and 3B are a plan view and a cross-sectional view showing steps of a method for manufacturing a substrate bonded body. [Figure 10] 3A and 3B are a perspective view and a cross-sectional view of a liquid ejection head, and a cross-sectional view of a protruding portion of a first substrate. [Figure 11] 4A and 4B are a plan view and a cross-sectional view of a protruding portion of a first substrate. [Figure 12] 4A and 4B are a plan view and a cross-sectional view of a protruding portion of a first substrate. [Figure 13] 3A and 3B are perspective views of a first substrate and a second substrate, and a perspective view of a protruding portion of the first substrate. [Figure 14] 1A and 1B are a plan view and a cross-sectional view of the adhesive transferred onto a second substrate. [Figure 15] FIG. 1 is a cross-sectional view of a substrate assembly shown in Patent Document 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The embodiment of this invention will be described in detail below.

[0012] (First embodiment) The substrate assembly according to this embodiment will be described with reference to Figs. 1 to 8 and Figs. 11 to 15. Fig. 1 shows a perspective view and a cross-sectional view of a substrate assembly 12 according to this embodiment. Fig. 2 shows an enlarged view of Fig. 1. The substrate assembly 12 is formed by bonding a second substrate 2 having an opening 5 and a first substrate 1 having a protruding portion 4 that defines the distance to the second substrate 2 with an adhesive 3 on the second substrate 2. The protruding portion 4 is positioned so as to surround the opening 5, and plays a role in defining the distance to the opposing second substrate 2 when the substrates are bonded. The protruding portion 4 has a groove 6 on the surface that contacts the adhesive 3. The groove 6 is connected to the end of the protruding portion 4. The groove is formed up to the end.

[0013] The first substrate 1 and the second substrate 2 may be processed substrates such as substrates with openings such as grooves and through holes, and substrates with integrated circuits and functional devices. The substrate assembly 12 is formed by combining these. The substrate assembly 12 may be applied in the form of individualized chips or wafers before being individualized. The materials of the first substrate 1 and the second substrate 2 may be, for example, Si, glass, ceramics, semiconductors, resins, etc. The first substrate 1 and the second substrate 2 are bonded via an adhesive 3, and the adhesive 3 remains there even after bonding. The adhesive 3 is made of a material that can bond to the surface of the second substrate 2 to be bonded, and may be, for example, a thermosetting resin. The adhesive 3 is formed in advance on the bonding surface of the second substrate 2 before bonding, and the adhesive 3 is pressed during bonding, and then the adhesive 3 is heated and cured to harden the adhesive 3, forming the substrate assembly 12.

[0014] FIG. 3 shows the process of bonding the first substrate 1 and the second substrate 2 via the adhesive 3 in the BB cross section of FIG. 2. In FIG. 3, the adhesive 3 has already been formed on the second substrate 2, as in FIG. 15. The process of bonding the first substrate 1 and the second substrate 2 is shown in chronological order as (a), (b), and (c). (a) shows the state before bonding, (b) shows the intermediate state of bonding, and (c) shows the flow of the adhesive when bonding is completed. In FIG. 15, in the bonding process, after the upper surface of the protrusion 4 faces the adhesive, bonding is continued until it comes into contact with the surface of the second substrate 2, so that some of the adhesive 3 has nowhere to go and overflows into the opening 5. On the other hand, in this case, a groove 6 is provided on the bonding surface of the protrusion 4, so the adhesive 3 is stored inside the groove 6 before overflowing into the opening 5. Therefore, it is possible to suppress the adhesive from overflowing into the opening 5. In addition, the adhesive 3 stored inside the groove 6 is connected to the area around the protruding portion 4 where the thickness of the adhesive 3 is thin, so that the excess adhesive is guided to the area where the thickness is thin. At this time, since the width of the groove is very narrow, for example, about 5 to 20 um, the adhesive with low viscosity is guided to fill the inside of the groove by the action of capillary action. Specifically, it enables the adhesive to be guided from the thick adhesive film portion 8 corresponding to the sides around the opening 5 in FIG. 8 to the thin adhesive film portion 7 corresponding to the four corners. Therefore, the unevenness of the adhesive film thickness around the opening is reduced, and the occurrence of voids caused by the thin film thickness of the adhesive 3 is suppressed. In addition, since the four sides of the opening 5 pass near the opening during the transfer process, the adhesive stagnates and acts to remain in place due to the influence of the surface tension around the opening. Therefore, it can be said that the adhesive formed at the four corners is relatively less affected by the surface tension, and therefore the thickness becomes thin. In addition, even in an adhesive with a relatively high viscosity at room temperature, when the viscosity of the adhesive decreases due to heating during bonding, the adhesive is guided by the action of capillary action.

[0015] The protruding portion 4 is not formed by processing the first substrate 1, but is formed by processing a separate member formed on the first substrate 1. For example, the protruding portion 4 may be formed of a part of the wiring layer, or may be formed of a material other than the wiring layer, such as an insulating material. In order to prevent the adhesive from overflowing into the opening 5, the groove 6 disposed in the protruding portion 4 is preferably shaped so as not to communicate the inside and outside of the protruding portion 4, as shown in FIG. 2(a).

[0016] When the adhesive 3 is transferred to the second substrate 2, there is a distribution in the thickness of the adhesive around the opening 5, and the thick and thin portions are determined by the transfer direction of the adhesive and the shape of the opening. Therefore, when the shape of the opening is circular, the distribution of the adhesive thickness is as shown in FIG. 14. By forming a groove in the protruding portion so that the thin portion 7 and the thick portion 8 communicate with each other, it is possible to guide the adhesive from the thick portion to the thin portion when the first substrate and the second substrate are bonded together. This makes it possible for the substrate assembly 12 to suppress the adhesive from overflowing into the opening and the occurrence of voids.

[0017] 2(a) shows the protrusion before the substrates are bonded together, and an adhesive has already been applied to the second substrate. The first substrate 1 and the second substrate 2 bonded together with the adhesive 3 form a substrate assembly 12 as shown in (b).

[0018] As shown in FIG. 2, the inner dimensions of the protrusion 4 are formed based on the shape of the opening 5 of the second substrate 2. For example, for a rectangular opening as shown in FIG. 2, it is preferable that the inner dimensions of the protrusion 4 are a rectangle that is one size larger than the opening. This is because the distance between the adhesive 3 and the opening 5 is constant when the substrates are bonded. As a result, the adhesive 3 formed on the second substrate comes into contact with the protrusion 4 of the first substrate, making it possible to suppress the adhesive from overflowing after the substrates are bonded. In addition, the adhesive 3 moves from the thick film portion of the adhesive to the thin film portion due to the groove 6 as shown in FIG. 3 during bonding, so that the occurrence of voids, which is a concern in the thin film portion, can be reduced at the same time.

[0019] 7, grooves 6 on the top surface of protrusion 4 connect the sides and corners of the protrusion, thereby enabling the movement of adhesive located at the sides and corners around opening 5 of the second substrate opposite the top surface of the protrusion. This allows the adhesive to be guided from thick adhesive film portions 8 located on the four sides around opening 5 to thin adhesive film portions 7 at the four corners, thereby preventing adhesive from spilling out into opening 5 and the generation of voids around the opening, which are concerns when joining substrates.

[0020] As shown in Fig. 13(a), the protrusion 4 may have a groove 6 on at least one of the four sides of the surface that contacts the adhesive 3. As shown in Fig. 13(b), by arranging a protrusion with a groove at a position facing the adhesive formed between adjacent openings, it is possible to prevent the adhesive from spilling out and to prevent the occurrence of voids. Fig. 13(c) shows an enlarged view of the protrusion 4.

[0021] The protrusion 4 may have grooves 6 on the surfaces of two of the four sides (opposite sides) that come into contact with the adhesive. It is also effective for any opening shape if the transfer direction 10 shown in FIG. 7 is perpendicular to the extension direction of the grooves 6. This can reduce the generation of voids in the thin film portion 7 around the opening 5 and the amount of adhesive 3 that protrudes into the opening 5 in the thick film portion 8. The grooves 6 may be disposed on any two or more sides, or may be disposed on all sides of the upper surface of the protrusion.

[0022] FIG. 4 shows a cross-sectional view of the protrusion 4 according to this embodiment. (a) and (b) are examples of shapes that satisfy the following conditions. When the cross-sectional area of ​​the groove on the side of the protrusion 4 corresponding to the FF cross section in the plan view of the protrusion 4 shown in FIG. 5 is SF, and the cross-sectional area of ​​the groove on the corner of the protrusion corresponding to the GG cross section is SG, the relationship is SF>SG. If the relationship between the depth D and width W of the groove is applied to this, then DF×WF>DG×WG. As a result, the cross-sectional area of ​​the groove 6 becomes smaller toward the four corners of the protrusion, and as a characteristic of the capillary phenomenon, the fluid moves from the larger cross-sectional area to the smaller cross-sectional area. As a result, the adhesive is filled up to the end of the groove, and the occurrence of voids due to the thin film portion of the adhesive 3 can be reduced.

[0023] Fig. 5 shows a plan view of the protruding portion 4 showing an example of the first embodiment of the present embodiment. When the width of the groove on the side of the protruding portion is W1 and the width of the groove 6 at the corner of the protruding portion is W2, the relationship is W1 > W2. When bonding the substrates as shown in Fig. 7, since the adhesive 3 needs to move a lot from the opening side portion 8 to the thin film portions 7 at the four corners of the opening, W1 is made larger than W2. This has the effect of reducing the amount of adhesive oozing out. Also, by making W2 smaller than W1, the thick film portion of the adhesive is filled in the groove 6 with a wide width W2. Further, in the process of bonding the substrates together, due to the capillary action that actively moves the fluid from the wide portion W2 of the groove 6 at the corner of the protruding portion 4 to the narrow portion W1 of the groove 6 at the corner of the protruding portion 4, the adhesive 3 is guided to the corners. As a result, the adhesive is sufficiently supplied to the corners around the opening where the generation of voids after bonding is a concern.

[0024] Fig. 6 shows a plan view and a cross-sectional view of the protruding portion 4 showing an example of the first embodiment of the present embodiment. When the depth of the groove at the side portion of the protruding portion is D1 and the depth of the groove at the corner of the protruding portion is D2, the relationship is D1 < D2. As shown in Fig. 7, the side portions around the opening have a thicker adhesive than the four corners. Therefore, when bonding the substrates, the adhesive contacts the side portion of the protruding portion 4 facing the adhesive and is accommodated inside the groove 6. In order to guide the accommodated adhesive to the thin film portions 7 at the four corners around the opening 5, an inclination may be provided in the groove. As a result, when bonding the substrates together, the side portion where the adhesive becomes a thick film and the side portion with the shallowest groove depth come into contact first, and by utilizing the inclination of the groove to actively extrude the adhesive to the corner of the groove, it becomes possible to guide it to the thin film portion at the corner. Thereby, the generation of voids due to the film thickness distribution of the adhesive and the oozing out to the opening 5 can be suppressed. Also, since the relationship of the groove depth is D1 < D2, as the function of capillary action, it is assumed that the adhesive is guided to the side portion with a small depth. However, since the groove has a sufficient width, in order to guide the adhesive in the region where the capillary action does not function, the adhesive is guided from the side portion to the corner portion.

[0025] FIG. 9 shows a plan view (a) and cross-sectional views (b) to (d) of the substrate assembly according to this embodiment. FIG. 9(d) shows a substrate assembly 12 constituting a part of the liquid ejection head 18 of FIG. 10. When providing the piezoelectric element 13 on the first substrate 1, for example, the convex shape of the wiring may be used as the protrusion 4. It is preferable to form an insulating film on the surface of the wiring. For example, Al may be used as the wiring material, or other wiring materials may be used. By using the wiring as the protrusion 4 and forming a groove in the protrusion 4 as shown in FIG. 9(c), it is possible to reduce the overflow of the adhesive 3 into the opening 5 and reduce the occurrence of voids. It is possible to form the protrusion 4 and the groove 6 by, for example, dry etching in the process of forming the wiring. The groove 6 of the protrusion 4 can be processed at the same time as the protrusion is formed, so that it is easy to introduce it since no new process is required.

[0026] As described above, according to this embodiment, it is possible to provide a substrate assembly in which the adhesive is reduced from spilling out into the openings, thereby reducing the occurrence of voids.

[0027] Second embodiment The method for producing a substrate bonded body according to this embodiment will be described with reference to FIGS.

[0028] 10 shows (a) a perspective view, (b) a cross-sectional view, and (c) an enlarged cross-sectional view of a protruding portion of a liquid ejection head 18. The liquid ejection head 18 is formed by bonding the substrate assembly 12 and a third substrate 16 having an ejection port 17 using the adhesive 3.

[0029] Figure 9 shows a method for manufacturing a substrate assembly 12. A first substrate 1 is prepared on which a piezoelectric element 13, which serves as the energy source for discharging liquid, and Al wiring are formed. A larger recessed hole 14 is formed in the second substrate 2 at a position facing the piezoelectric element 13 of the first substrate 1, as shown in Figure 9(b). At the same time, an opening 5 is formed to serve as a liquid flow path. Next, a protrusion 4 having a shape that surrounds the outer periphery of the opening 5 is formed at a position facing the opening 5 by etching the Al wiring of the first substrate 1.

[0030] Next, as shown in FIG. 9(c), the adhesive is spread on the support so that the film thickness is uniform, and then the second substrate and the adhesive-coated surface of the support are arranged so that they face each other. The adhesive 3 is transferred from above the support to the surface of the second substrate having the piezoelectric element vibration section using a roller 15. At this time, a part of the adhesive is transferred only to the part that comes into contact with the adhesive, so that the adhesive does not enter the piezoelectric element vibration space 14 and the opening 5. Then, the processed first substrate surface and the adhesive-coated second substrate surface are bonded together so that they face each other. At this time, pressure is applied to the position where the upper surface of the protrusion 4 formed on the first substrate 1 comes into contact with the surface of the second substrate bonding surface, thereby reducing the variation in the distance between the substrates. Then, the substrate is heated at a temperature at which the adhesive hardens to form a substrate bonded body 12.

[0031] FIG. 9(d) shows the positional relationship when the substrates are bonded together. The substrates are bonded together so that the extension direction of the groove 6 is perpendicular to the direction in which the adhesive is transferred. As a result, even in any opening shape, including a circle, shown in FIG. 14, the groove is positioned so that the thin film portion and the thick film portion of the adhesive are connected, so that the adhesive is guided during the substrate bonding process, and the overflow of the adhesive and the occurrence of voids can be suppressed. In addition, since the groove 6 is connected to the end of the protrusion 4, the adhesive is guided from the thick adhesive portion to the thin adhesive portion, so the occurrence of voids can be reduced.

[0032] Furthermore, when there are multiple openings 5 ​​on the second substrate 2, by forming the adhesive in the direction in which the openings are more densely arranged, the thin film of adhesive formed around the openings overlaps with the thin film of the adjacent openings. As a result, one groove is required for every two openings to guide the adhesive when bonding the substrates together. This is shown in Figure 13(c).

[0033] FIG. 9(d) shows the relationship between the extending direction 11 of the groove 6 and the direction 10 of transferring the adhesive when bonding the substrates. The adhesive is formed by transferring from a direction rotated by 90° with respect to the longitudinal direction of the piezoelectric element vibration space 14. If the adhesive is transferred parallel to the longitudinal direction of the piezoelectric element vibration space 14, there is a concern that the adhesive 3 may get into the upper part of the piezoelectric element vibration space 14 where no adhesive is actually required. In addition, the first substrate and the second substrate are bonded together so that the groove 6 extends in a direction perpendicular to the transfer direction of the adhesive 3. Therefore, the groove extends so as to be approximately parallel to the longitudinal direction of the piezoelectric element vibration space on the surface of the second substrate. Therefore, even if the adhesive 3 has a film thickness distribution as shown in FIG. 7, the adhesive is guided from the thick film portion to the thin film portion by the groove 6, and the occurrence of voids, which is a concern in the thin film portion, can be reduced at the same time.

[0034] Therefore, according to this embodiment, it is possible to provide a method for manufacturing a substrate bonded body in which the adhesive is reduced from spilling out into the openings, thereby reducing the occurrence of voids. EXAMPLES

[0035] The substrate bonded body 12 implemented was formed by using silicon for the first substrate 1, silicon for the second substrate 2, and Al wiring for the protruding portion 4. The second substrate 2 had an opening 5 of K×J=96×88 um, as shown in FIG. 11(a). The protruding portion 4 needed to be positioned so as to surround the outer periphery of the opening 5 of the second substrate 2, and in consideration of the misalignment of the substrates during bonding, the inner diameter of the protruding portion 4 was set to L1×M1=100×92 um, which is 2 um larger than the dimensions of the opening 5 in FIG. 11(a). In addition, the outer diameter of the protruding portion 4 was set to L2×M2=160×152 um, which is 3 um smaller than the adjacent wiring, in order to avoid interference with the adjacent Al wiring.

[0036] The height of the protrusion is set to 4 um to define the distance between the substrates after bonding. When the surface facing the second substrate 2 is the upper surface of the protrusion when bonding the substrates, a groove 6 with a width W=20 um and a depth D2=1 to 4 um is formed on this surface so as to be parallel to the four sides of the protrusion 4. The groove 6 is shallowest at the center of the side and becomes deeper toward the corners of the protrusion 4, so that a shape with a stepped height is formed by repeating patterning and dry etching multiple times. In addition, the depth of the groove at the corners of the protrusion 4 is etched to 4 um, which is the same as the height of the protrusion. The first substrate 1 having the protrusion 4 with the groove 6 formed therein and the second substrate 2 having the adhesive 3 are bonded together. The substrate bonded body 12 after bonding was observed with an IR camera to confirm that the adhesive did not overflow into the opening 5 and that no voids were generated around the protrusion 4. This enabled the verification of the adhesive induction effect by the groove 6. EXAMPLES

[0037] The manufacturing method of the protrusion will be described. FIG. 12 shows protrusions with different groove widths. The outer dimensions of the opening 5 and protrusion 4 on the second substrate 2 are 96×88 um for the opening 5 and 160×152 um for the protrusion, as in FIG. 11. Unlike Example 1, the overall depth of the groove 6 to be formed is the same as the height of the Al protrusion, 4 um, so processing was performed by one patterning and etching. The dimensions of the groove are 20 um for the center part W1 of the side and 5 um for the corner part W2, and the width is gradually narrowed from the center part of the side to the corner part. As in Example 1, after bonding the first substrate 1 having the protrusion 4 with the groove 6 processed therein and the second substrate 2 having the opening 5 with the adhesive 3, the overflow of the adhesive and the presence or absence of voids around the opening were evaluated using an IR camera. As a result, it was confirmed that the amount of overflow of the adhesive was reduced and no voids were generated.

[0038] (composition) [Configuration 1] In a substrate assembly in which a first substrate and a second substrate are bonded with an adhesive, a protrusion protruding toward the second substrate is formed on a surface of the first substrate to which the adhesive is attached; The second substrate has an opening formed therein, The protruding portion is arranged to surround the opening, A groove is formed on the upper surface of the protruding portion, The groove extends to the end of the protruding portion. A substrate bonding body characterized by this.

[0039] [Configuration 2] The substrate bonding body according to Configuration 1, wherein at least one groove is formed.

[0040] [Configuration 3] The substrate bonding body according to Configuration 1 or 2, wherein the groove does not communicate with the inner wall of the protruding portion.

[0041] [Configuration 4] When the cross-sectional area of the groove on the side of the protruding portion is S1 and the cross-sectional area of the groove at the corner of the protruding portion is S2, the substrate bonding body according to any one of Configurations 1 to 3, having a relationship of S1 > S2.

[0042] [Configuration 5] When the width of the groove on the side of the protruding portion is W1 and the width of the groove at the corner of the protruding portion is W2, the substrate bonding body according to any one of Configurations 1 to 4, having a relationship of W1 > W2.

[0043] [Configuration 6] When the depth of the groove on the side of the protruding portion is D1 and the depth of the groove at the corner of the protruding portion is D2, the substrate bonding body according to any one of Configurations 1 to 5, having a relationship of D1 < D2.

[0044] [Configuration 7] A liquid ejection head having the substrate bonding body, wherein the protruding portion is a part of a wiring structure of the liquid ejection head. A liquid ejection head characterized by this.

[0045] [Configuration 8] A step of preparing a second substrate having at least one opening, A protruding portion forming step of forming a protruding portion having a shape surrounding the opening on a first substrate, a groove forming step of forming a groove on an upper surface of the protruding portion; an adhesive transfer step of transferring an adhesive to a surface of the second substrate having an opening; a substrate bonding step of bonding the first substrate and the second substrate to each other via the adhesive so that the opening and the protruding portion face each other coaxially, The method for producing a substrate assembly, wherein the bonding step bonds the substrates together such that the extension direction of the grooves is perpendicular to the transfer direction of the adhesive.

[0046] [Configuration 9] The adhesive transfer step transfers the adhesive in the same direction as the direction in which the openings are densely arranged, 9. The method for producing a substrate assembly according to configuration 8, wherein the bonding step bonds the substrates together so that the extending direction of the grooves is perpendicular to the densely arranged direction of the openings.

[0047] [Configuration 10] A method for manufacturing a liquid ejection head that ejects liquid using a piezoelectric element provided on a first substrate, comprising the steps of: A method for manufacturing a liquid ejection head in which a second substrate having a piezoelectric element vibration space and a liquid supply port, a first substrate having the protrusion positioned so as to surround the liquid supply port, and a third substrate facing the first substrate and having the liquid ejection port are bonded together via an adhesive, the method comprising: an adhesive transfer step of transferring an adhesive to a surface of the second substrate having an opening; a substrate bonding step of bonding the first substrate and the second substrate together via the adhesive so that the liquid supply port and the protruding portion are coaxially opposed to each other; A method for manufacturing a liquid ejection head, comprising a third substrate bonding step of bonding the first substrate and the third substrate together via the adhesive, A method for manufacturing a liquid ejection head, wherein the adhesive transfer step transfers the adhesive so as to be perpendicular to a longitudinal direction of a piezoelectric element vibration space formed on the second substrate. [Explanation of symbols]

[0048] 1 First Substrate 2 Second Board 3. Glue 4 Protrusion 5 aperture 6 grooves

Claims

1. In a substrate assembly in which a first substrate and a second substrate are bonded with an adhesive, a protrusion protruding toward the second substrate is formed on a surface of the first substrate to which the adhesive is attached, The second substrate has an opening formed therein; The protrusion is disposed so as to surround the opening, A groove is formed on the upper surface of the protrusion, The substrate assembly, wherein the groove extends to an end of the protrusion.

2. 2. The substrate assembly according to claim 1, wherein at least one groove is formed.

3. The substrate assembly according to claim 1 , wherein the groove does not communicate with an inner wall of the protrusion.

4. 2. The substrate assembly according to claim 1, wherein when a cross-sectional area of ​​the groove on the side of said protrusion is S1 and a cross-sectional area of ​​the groove on the corner of said protrusion is S2, the relationship S1>S2 is satisfied.

5. 2. The substrate assembly according to claim 1, wherein the relationship W1>W2 is satisfied, where W1 is the width of the groove on the side of the protrusion, and W2 is the width of the groove on the corner of the protrusion.

6. 2. The substrate assembly according to claim 1, wherein the depth of the groove on the side of the protrusion is D1 and the depth of the groove on the corner of the protrusion is D2, and the relationship D1<D2 is satisfied.

7. 2. A liquid ejection head having the substrate assembly according to claim 1, wherein the protrusion is a part of a wiring structure of the liquid ejection head.

8. Providing a second substrate having at least one opening; a protrusion forming step of forming a protrusion having a shape surrounding the opening on the first substrate; a groove forming step of forming a groove on an upper surface of the protruding portion; an adhesive transfer step of transferring an adhesive to a surface of the second substrate having an opening; a substrate bonding step of bonding the first substrate and the second substrate to each other via the adhesive so that the opening and the protruding portion face each other coaxially, The method for producing a substrate assembly, wherein the bonding step bonds the substrates together such that the extension direction of the grooves is perpendicular to the transfer direction of the adhesive.

9. The adhesive transfer step transfers the adhesive in the same direction as the direction in which the openings are densely arranged, 9. The method for manufacturing a substrate assembly according to claim 8, wherein the bonding step bonds the substrates together such that a direction in which the grooves extend and a direction in which the openings are densely arranged are perpendicular to each other.

10. A method for manufacturing a liquid ejection head that ejects liquid using a piezoelectric element provided on a first substrate, comprising the steps of: A method for manufacturing a liquid ejection head in which a second substrate having a piezoelectric element vibration space and a liquid supply port, a first substrate having a protrusion positioned so as to surround the liquid supply port, and a third substrate facing the first substrate and having a liquid ejection port are bonded together via an adhesive, the method comprising: an adhesive transfer step of transferring an adhesive to a surface of the second substrate having an opening; a substrate bonding process of bonding the first substrate and the second substrate together via the adhesive so that the liquid supply port and the protruding portion face each other coaxially; a third substrate bonding step of bonding the first substrate and the third substrate together via the adhesive, A method for manufacturing a liquid ejection head, wherein the adhesive transfer step transfers the adhesive so as to be perpendicular to a longitudinal direction of a piezoelectric element vibration space formed on the second substrate.

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