Substrate bonding method, substrate bonded body, and inkjet print head

Abstract

The present invention provides a substrate bonding method, a substrate bonded body, and an inkjet print head that do not create leak paths in the adhesive when joining components together. [Solution] The bonding method comprises the steps of: applying a first adhesive in a line to the bonding region of a first substrate to form a first adhesive layer; applying a second adhesive in a line and discontinuously at predetermined intervals to the line-shaped first adhesive layer in the bonding region of the first substrate to form a plurality of second adhesive layers having gaps due to the discontinuity; bonding the second substrate to the first substrate with the first adhesive layer and the plurality of second adhesive layers and pressing the second substrate to the first substrate; curing the plurality of second adhesive layers on the first and second substrates that are being pressed together; and curing the first adhesive layer after the plurality of second adhesive layers have cured.

Description

Technical Field

[0001] The present invention relates to a substrate bonding method, a substrate bonded body, and an inkjet print head, and more particularly to a technique for bonding substrates using temporary fixing with a thermosetting adhesive.

Background Art

[0002] Patent Document 1 describes a technique for bonding substrates using a thermosetting temporary adhesive in the same manner as a thermosetting main adhesive having a relatively strong adhesive force. Here, the temporary adhesive is spot-coated on the bonding surface of the substrates and cured in a process prior to the main adhesive to temporarily bond the substrates together. However, in the case of spot coating, for example, when bonding a substrate with low wettability such as a semiconductor substrate used for an inkjet head to another substrate, it is difficult to control the coating amount and the coating amount is not stable. In addition, even if it is coated, it is difficult to ensure the required adhesive force.

[0003] On the other hand, when applying the adhesive in a line shape, the coating amount can be stably controlled, and it is also possible to ensure the adhesive force of the adhesive.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when applying the linear main adhesive and the temporary adhesive in close proximity, air bubbles may be entrapped between these two adhesives. And these entrapped air bubbles expand when heating and curing the main adhesive, causing a leak path that penetrates the main adhesive, which may cause defects in products using the bonded substrates.

[0006] The purpose of this disclosure is to provide a substrate bonding method, a substrate bonded body, and an inkjet print head that do not create a leak path in the adhesive when joining components together. [Means for solving the problem]

[0007] This disclosure is characterized in that the bonding method comprises the steps of: applying a first adhesive in a line to the bonding region of a first substrate to form a first adhesive layer; applying a second adhesive in a line at predetermined intervals to the line-shaped first adhesive layer in the bonding region of the first substrate so that the line is intermittent to form a plurality of second adhesive layers having gaps due to the intermittence; bonding the second substrate to the first substrate with the first adhesive layer and the plurality of second adhesive layers to press the second substrate to the first substrate; curing the plurality of second adhesive layers on the first and second substrates that are being pressed together; and curing the first adhesive layer after the plurality of second adhesive layers have cured. [Effects of the Invention]

[0008] According to this disclosure, by continuously pressing together the first and second substrates to be joined, as the first adhesive layer formed by this adhesive approaches the second adhesive layer formed by the temporary adhesive, air between the first and second adhesive layers flows into the gap between the two adjacent second adhesive layers, preventing a leak path from forming in the first adhesive layer. [Brief explanation of the drawing]

[0009] [Figure 1] (a) to (e) Top view showing the state in which the temporary adhesive and the main adhesive have been applied to the bonding surface of the substrates to be joined, according to the comparative example. [Figure 2] (a) to (e) are cross-sectional views of Figure 1 along line AA, corresponding to Figures 1(a) to (e). [Figure 3] This is a plan view showing two substrates to be joined together, along with the joining region, according to one embodiment. [Figure 4] A flowchart showing the process of joining the first substrate and the second substrate according to this embodiment. [Figure 5] (a) A diagram illustrating the application of this adhesive to the first substrate in step 401 of Figure 4. (b) A magnified view of a part of the first substrate shown in Figure 5(a). [Figure 6] (a) A diagram illustrating the application of temporary adhesive to the first substrate in step 402 of Figure 4. (b) A magnified view of a portion of the first substrate shown in Figure 6(a). [Figure 7] This diagram illustrates the process of pressing the second substrate onto the first substrate in step 403. [Figure 8] (a) A diagram showing the process of joining the first substrate and the second substrate according to this embodiment. (b) to (e) Diagrams illustrating the changes in the form of the main adhesive and the temporary fixing adhesive during the process of joining the first substrate and the second substrate in Figure 4. [Figure 9] A diagram illustrating the application of adhesive according to another embodiment. [Figure 10] A diagram illustrating the application of adhesive according to another embodiment. [Figure 11] This figure shows a first substrate in a comparative example where no gaps are left when applying temporary adhesive before pressing. [Figure 12] This figure shows a first substrate in a comparative example where no gap is left when applying temporary adhesive during pressing. [Figure 13] This is an explanatory diagram showing an inkjet print head according to this embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below with reference to the drawings. Note that the dimensions, materials, shapes, and relative arrangements of the components described in the embodiments should be appropriately modified depending on the configuration of the device to which the invention is applied and various conditions, and the scope of this invention is not intended to be limited to the following embodiments.

[0011] First, before describing the embodiments of the present invention, the generation of leak paths when applying and bonding a linear temporary adhesive and the present adhesive in close proximity to each other will be described with reference to the comparative examples shown in FIGS. 1 and 2. FIGS. 1(a) to (e) are top views showing a state in which a temporary adhesive and the present adhesive are applied to the bonding surface of substrates to be joined according to the comparative example, and FIGS. 2(a) to (e) are cross-sectional views taken along line A-A of FIG. 1 corresponding to FIGS. 1(a) to (e), respectively.

[0012] In the application and bonding process, first, a linear present adhesive (also referred to as the first adhesive) 14 and a temporary adhesive (also referred to as the second adhesive) 12 are applied in parallel to the substrate 10 at a narrow interval (FIGS. 1(a) and 2(a)), and the substrate 10 to be joined and the substrate 20 are joined to each other (FIGS. 1(b) and 2(b)). In this state, the substrate 20 is pressed against the substrate 10 (FIGS. 1(c) and 2(c)). Then, the temporary adhesive 12 is thermocompression bonded to cure only the temporary adhesive 12, and the substrate 10 is temporarily fixed to the substrate 20 (FIGS. 1(c) and 2(c)). Next, the substrates 10 and 20 joined by temporary fixing are heated in an oven to cure the present adhesive (FIGS. 1(d) and 2(d)).

[0013] Here, when applying the linear present adhesive 14 and the temporary adhesive 12 to the substrate 10, the coating device moves along a line and applies the adhesive in a line. At this time, due to the influence of acceleration and deceleration of the application speed, the application amount at the start of the adhesive application and the application amount at the end of the adhesive application in the line shape may increase. In this case, at the time of pressure bonding shown in FIGS. 1(c) and 2(c), the temporary adhesive 12 and the present adhesive 14 are joined at their both ends, and the air between the temporary adhesive 12 and the present adhesive 14 is finally taken in as air bubbles 30 shown in FIGS. 1(d) and 2(d).

[0014] As a result, when heating the substrate 10 and the substrate 20 in an oven as shown in FIGS. 1(d) and 2(d), the entrapped bubbles 30 expand. However, since the temporary adhesive 12 has already cured and the main adhesive 14 is in the process of curing, the expanding bubbles 30 break through the softer main adhesive 14 to form a leak path (FIGS. 1(e) and 2(e)). Such a leak path is used, for example, for the purpose of separating the inside and the outside by applying the adhesive in a U-shape, such as in the bonding of a semiconductor substrate in an inkjet print head. In this example, ink reaches the outer temporary adhesive through the leak path. As a result, the relatively ink-resistant low temporary adhesive peels off or the like, causing defects in the product such as the ink reaching the electrical wiring portion arranged outside the U-shape and causing a short circuit.

[0015] An embodiment of the present disclosure prevents the formation of a leak path due to the entrapped bubbles described above.

[0016] FIGS. 3(a) and (b) are plan views showing two substrates to be joined together with a joining region according to an embodiment. On the surface of the first substrate 100 shown in FIG. 3(a), there is a joining region 110, and an adhesive can be applied to the joining region 110. Specifically, the joining region 110 is a region formed along the side 120 of the first substrate 100 on the surface of the first substrate 100. In the present embodiment, the first substrate 100 is a semiconductor substrate having external connection wiring terminals. On the other hand, the second substrate 200 shown in FIG. 3(b) has a rectangular opening 210. In the present embodiment, the second substrate 200 is a metal substrate having heat conductivity. The outer periphery 212 of the opening 210 corresponds to the inner periphery 112 of the joining region 110 of the first substrate 100, and when the adhesive is applied to the joining region 110, the inner periphery 112 of the joining region 110 of the first substrate 100 is aligned with the outer periphery 212 of the opening 210 of the second substrate 200 and bonded. Then, by curing the adhesive, the first substrate 100 is fixed to the second substrate 200.

[0017] Figure 4 is a flowchart illustrating the process of joining the first substrate 100 and the second substrate 200 according to this embodiment. First, in step 401, the adhesive 130 is applied to the joining region 110 of the first substrate 100. Figures 5(a) and 5(b) illustrate this application, with Figure 5(b) being an enlarged view of a part of the first substrate 100 shown in Figure 5(a). As shown in these figures, the adhesive 130 is applied in a line along the inner circumference 112 (inner boundary) of the joining region 110 on the substrate 100. In this embodiment, the adhesive 130 is a thermosetting adhesive that has relatively strong adhesive strength and a relatively long curing time.

[0018] Next, in step 402, temporary adhesive 140 is intermittently applied to the first substrate 100 in an area of ​​the bonding region 110 that is spaced apart from the main adhesive 130. Figures 6(a) and 6(b) illustrate this application, with Figure 6(b) being an enlarged view of a portion of the first substrate 100 shown in Figure 6(a). As shown in these figures, the temporary adhesive 140 is applied at predetermined narrow intervals outside the area of ​​the bonding region 110 on the first substrate 100 where the main adhesive 130 has been applied. The intermittent application of the temporary adhesive 140 creates gaps 150 between adjacent temporary adhesives 140. Since the application of the temporary adhesive 140 is carried out while moving the application device in a straight line (in the lateral direction in Figure 6), at least the ends of each adjacent temporary adhesive 140 are not affected by the acceleration and deceleration of the application device described above, and therefore the amount of adhesive applied at the ends does not increase.

[0019] In this embodiment, the temporary adhesive 140 is an adhesive that can cure in a short time. For example, the temporary adhesive 140 is a thermosetting adhesive having a shorter curing time and a lower curing temperature than the adhesive 130. In other embodiments, the temporary adhesive 140 may be an ultraviolet-curable adhesive having a short curing time.

[0020] As shown in Figure 6(a), in this embodiment, the temporary adhesive 140 is applied along two opposing short sides 121 of the first substrate 100 (i.e., the outer circumference of the bonding region 110). Here, the portion of the bonding region 110 adjacent to the short sides 121 of the first substrate 100 has a first length L1 to which both the main adhesive 130 and the temporary adhesive 140 are applied, and the portion of the bonding region 110 adjacent to the long side 122 of the first substrate has a second length L2 to which only the main adhesive 130 is applied. The second length L2 is shorter than the first length L1. As a result, the portion of the first substrate 100 to which neither the main adhesive 130 nor the temporary adhesive 140 is applied can be used efficiently. In this embodiment, the first length L1 is approximately 1 mm.

[0021] Referring again to Figure 4, in step 403, the second substrate 200 is pressed onto the first substrate 100. Figure 7 is a diagram illustrating this pressing operation. As shown in Figure 7, the pressing device 300 aligns the second substrate 200 with the first substrate 100, brings the first substrate 100 and the second substrate 200 close to each other, and the second substrate 200 is bonded to the first substrate 100 using the temporary adhesive 140 and the main adhesive 130 on the first substrate 100, thereby pressing the second substrate 200 onto the first substrate 100. More specifically, negative pressure is applied to the first substrate 100 and the second substrate 200 through the suction holes (not shown) of two opposing fingers 310 of the pressing device 300, causing the first substrate 100 and the second substrate 200 to be attracted to the corresponding fingers 310. In this process, the surface of the first substrate 100 to which the main adhesive 130 and the temporary adhesive 140 are applied is substantially parallel to the surface of the second substrate facing that surface. The crimping device 300 then aligns the bonding area 110 of the first substrate 100 with the second substrate 200, and the two fingers 310 of the crimping device 300 approach each other in a direction perpendicular to the surfaces of the first substrate 100 and the second substrate 200 (see Figure 8(b)).

[0022] Next, in step 404, with the first substrate 100 pressed against the second substrate 200, the application area of ​​the temporary adhesive 140 is heated to cure only the temporary adhesive 140. Specifically, when the pressing device 300 shown in Figure 7 bonds the second substrate 200 to the first substrate 100, a heater (not shown) installed on the finger 310 heats the second substrate 200, which is a metal substrate. As the temperature of the second substrate 200 rises, the temporary adhesive 140 is heated, and when the heating temperature reaches the curing temperature of the temporary adhesive 140, the temporary adhesive layer (also called the second adhesive layer) 140a formed by the temporary adhesive 140 is cured. At this time, the main adhesive 130 remains uncured because its curing temperature is higher. Note that the form of curing the temporary adhesive 140 is not limited to this example. For example, it is also possible to heat only the temporary adhesive 140. In this configuration, it is not necessary to set the curing temperature of the main adhesive 130 higher than that of the temporary adhesive 140.

[0023] Next, in step 405, the main adhesive 130 is cured. Specifically, the first and second substrates, which are joined with the temporary adhesive 140, are placed in an oven and the entire joined substrate is heated to the curing temperature of the main adhesive. This heating causes the main adhesive layer (also called the first adhesive layer) 130a formed by the main adhesive 130 to harden.

[0024] Figures 8(b) to 8(e) illustrate the changes in the morphology of the main adhesive 130 and the temporary adhesive 140 during the process of joining the first substrate 100 and the second substrate 200 as described in Figure 4. Figure 8(a) shows the process of joining the first substrate 100 and the second substrate 200 according to this embodiment, Figures 8(b) and (c) show the cross-section along line AA of Figure 8(a), and Figures 8(d) and (e) show the cross-section along line BB of Figure 8(a).

[0025] In the regions shown in Figures 8(b) and (c), when the main adhesive 130 and the temporary adhesive 140 are pressed together, they move closer to each other, narrowing the distance between them. At that time, the air between them moves along the space of the adhesives because the ends of the main adhesive 130 and the temporary adhesive 140 are not joined, and flows out through the gap 150 at the end of the temporary adhesive 140. On the other hand, in the regions shown in Figures 8(d) and (e), since the gap 150 exists, there is no room for air bubbles to be trapped, and as described above, it becomes an outlet for the air that moves along the space 101 of the adhesive.

[0026] In this embodiment, the two adjacent cured temporary adhesive layers 140a do not come into contact with each other, and the gap 150 communicates with the outside of the substrate bond, so that the air between the main adhesive layer 130a and the temporary adhesive layer 140a can be discharged to the outside through the gap 150. In another embodiment, if the air between the main adhesive layer 130a and the temporary adhesive layer 140a does not flow into the gap 150 and form air bubbles in the uncured main adhesive layer 130a, the two adjacent cured temporary adhesive layers 140a may come into contact with each other, and one end of the gap may be closed.

[0027] Figures 9(a) and (b) and 10(a) and (b) illustrate the application of the adhesive according to other embodiments of the present disclosure. Figures 9(a) and (b) show an increased number of intermittent application gaps 150, and Figures 10(a) and (b) show an increased length of the gaps 150. These configurations allow air to escape more easily between the main adhesive layer 130a and the temporary adhesive layer 140a, and enhance the effect of preventing air bubbles from being trapped between the main adhesive layer 130a and the temporary adhesive layer 140a. However, the adhesive force of the temporary adhesive layer 140a must ensure the necessary adhesive force to fix the first substrate 100 and the second substrate 200. Therefore, the total length of the temporary adhesive layer 140a must be longer than the length of the gaps 150. For example, if the length of the multiple temporary adhesive layers 140a is two-thirds or more of the length of the side edge 120 of the first substrate 100 adjacent to the multiple temporary adhesive layers 140a, that is, if the length of the gap 150 is one-third or less of the length of the side edge 120, then air can easily escape between the main adhesive layer 130a and the temporary adhesive layer 140a, which has the effect of preventing air bubbles from being trapped between the main adhesive layer 130a and the temporary adhesive layer 140a.

[0028] Next, the present invention will be described in more detail with reference to specific examples.

[0029] (Example 1) The first substrate 100 shown in Figure 3(a) is a semiconductor substrate obtained by stacking various wafers and then dicing them, and has dimensions of 1 mm thickness, 13 mm width, and 29 mm length. Furthermore, the second substrate 200 shown in Figure 3(b) is a Ti-based metal substrate, and has dimensions of 100 μm thickness, 22 mm width, and 39 mm length. The second substrate 200 has a rectangular opening 210, which has dimensions of 100 μm thickness, 11 mm width, and 27 mm length.

[0030] Then, as shown in Figures 5(a) and 6(a), the main adhesive 130 and the temporary adhesive 140 are applied to the first substrate 100.

[0031] Subsequently, using the crimping device 300 shown in Figure 7, the second substrate 200 was heat-pressed onto the first substrate 100, which had been coated with the main adhesive 130 and temporary adhesive 140, at a temperature of 100°C for a crimping time of 60 seconds. At this time, only the temporary adhesive 140 hardened.

[0032] Then, the adhesive 130 was cured by heating the second substrate 200 onto the first substrate 100, which was to be heated and pressed in an oven (not shown), at 150°C for 2 hours. After that, the substrate joint formed by the first substrate 100 and the second substrate 200 was removed from the oven and allowed to cool, completing the bonding of the first substrate 100 and the second substrate 200.

[0033] On the other hand, when the second substrate 200, which is a metal plate, was peeled off from the first substrate 100, which is a semiconductor substrate, and observed, no bubbles were observed between the main adhesive layer 130a and the temporary adhesive layer 140a. In this embodiment, the main adhesive 130 is an adhesive that hardens when heated at a temperature of 150°C for 1 hour, and the temporary adhesive 140 is an adhesive that hardens when heated at a temperature of 80°C for 40 seconds.

[0034] (Comparative example) A comparative example in which no gaps are left when applying the temporary fixing adhesive of the present invention will be specifically described. In the comparative example, the first substrate 100, which is a semiconductor substrate, and the second substrate 200, which is a metal plate, are the same as in Example 1. The adhesive 130 and the temporary fixing adhesive 140 are applied to the first substrate 100 in a continuous line, as shown in Figure 11. That is, unlike Example 1, the second adhesive layer 140a does not leave a gap on the first substrate 100.

[0035] Then, the first substrate 100 and the second substrate 200 were heated and pressed together in the same manner as in Example 1, and after heating in an oven, the second substrate 200 was peeled off the first substrate 100 and observed. As shown in Figure 12(b), bubbles 30 were formed between the main adhesive layer 130a and the temporary adhesive layer 140a, that is, bubbles were embedded in the main adhesive layer 130a. As a result, internal pressure applied during heating, etc., may cause problems such as damage to the first substrate 100 or changes in the shape of the main adhesive layer 130a, or insufficient adhesive strength of the main adhesive layer 130a.

[0036] On the other hand, in Example 1, by intermittently applying the temporary adhesive 140, the first substrate 100 can be pressed onto the second substrate 200 while allowing air to escape from the gaps 150 between the temporary adhesives 140. This allows the first substrate 100 to be joined and fixed to the second substrate 200 without creating a leak path due to air trapped between the main adhesive layer 130a and the temporary adhesive 140.

[0037] Figure 13 is an explanatory diagram showing an inkjet print head. As shown in Figure 13, the inkjet print head 1 includes an ejection tip 11 having an ejection nozzle 11a, a first substrate 100, and a second substrate 200 having an opening 210. The ejection tip 11 is placed on the first substrate 100 and covered by the second substrate 200, with the ejection nozzle 11a of the ejection tip 11 surrounded by the opening 210 of the second substrate 200 and exposed through the opening 210.

[0038] In detail, the first substrate 100 in this embodiment is similar to the first substrate 100 shown in Figure 3(a), and the second substrate 200 is similar to the second substrate 200 shown in Figure 3(b). That is, the ejection chip 11 in this embodiment is installed on the substrate assembly formed in steps 401 to 405 shown in Figure 4. As a result, the second substrate 200, which is a metal substrate, is installed outside the ejection chip 11, so that the second substrate 200 can protect the ejection chip 11, the ejection chip 11 can be electrically connected to the electrical wiring section of the inkjet print head 1 by the first substrate 100, which is a semiconductor substrate, and ink can be ejected from the opening 210 of the second substrate 200 by the ejection nozzle 11a. In this embodiment, the ejection chip 11 is a silicon chip.

[0039] In this embodiment, since there is no leak path in the highly ink-resistant main adhesive layer 130a between the first substrate 100 and the second substrate 200 to be joined, the ink ejected from the ejection chip 11 cannot reach the less ink-resistant temporary adhesive layer 140a. This avoids the problem of the temporary adhesive layer 140a being weakened by the ink and peeling off from the first substrate 100 and the second substrate 200, and also avoids the problem of the ink reaching the electrical wiring portion of the first substrate 100 located outside the temporary adhesive layer 140a and causing a short circuit in the electrical wiring portion due to the ink.

[0040] <<Other Embodiments>> This disclosure includes the following substrate bonding method, substrate bonded body, and configuration represented by an inkjet print head.

[0041] <Configuration 1> A step of applying a first adhesive in a line to the bonding region of the first substrate to form a first adhesive layer, In the bonding region of the first substrate, a step of applying a second adhesive in a line shape to the line-shaped first adhesive layer at predetermined intervals, such that the line is intermittent, thereby forming a plurality of second adhesive layers having gaps due to the intermittences, A step of bonding the second substrate to the first substrate using the first adhesive layer and the plurality of second adhesive layers, and pressing the second substrate to the first substrate, The process involves curing the plurality of second adhesive layers in the first and second substrates that are to be pressed together, After the plurality of second adhesive layers have hardened, a step is made to harden the first adhesive layer. A joining method characterized by having the following features.

[0042] <Configuration 2> The joining method according to configuration 1, characterized in that the length of each of the plurality of second adhesive layers is longer than the length of the gap.

[0043] <Structure 3> The bonding method according to configuration 1, characterized in that the plurality of second adhesive layers are installed along two opposing sides of the outer circumference of the bonding region.

[0044] <Structure 4> The bonding method according to configuration 1, characterized in that the first substrate is a semiconductor substrate and the second substrate is a metal substrate.

[0045] <Composition 5> The bonding method according to configuration 1, characterized in that the second substrate has an opening, and the inner circumference of the bonding region corresponds to the outer circumference of the opening.

[0046] <Composition 6> The bonding method according to configuration 1, characterized in that the length of the plurality of second adhesive layers is two-thirds or more of the length of the side edge of the first substrate adjacent to the plurality of second adhesive layers.

[0047] <Composition 7> The joining method according to configuration 1, characterized in that the first adhesive layer is composed of a thermosetting adhesive.

[0048] <Structure 8> The bonding method according to configuration 7, characterized in that the plurality of second adhesive layers are made of a material that hardens at a lower temperature than the first adhesive layer.

[0049] <Composition 9> The bonded first substrate and second substrate, A first adhesive layer formed in a line shape between the first substrate and the second substrate by a first adhesive, A plurality of second adhesive layers are formed by a second adhesive, adjacent to the aforementioned linear first adhesive layer, and are linear in shape with gaps between the lines. A joint characterized by comprising the following features.

[0050] <Composition 10> The bonded first substrate and second substrate, A first adhesive layer formed in a line shape between the first substrate and the second substrate by a first adhesive, Adjacent to the aforementioned linear first adhesive layer are a plurality of linear second adhesive layers formed by a second adhesive, which are linear in shape and have gaps between the lines, A discharge tip installed on the first substrate, covered by the second substrate, and having a discharge nozzle, wherein the discharge nozzle is surrounded by an opening in the second substrate and exposed from the opening, An inkjet printhead characterized by having the following features.

[0051] <Composition 11> The inkjet print head according to configuration 10, characterized in that the length of the plurality of second adhesive layers is longer than the length of the gap.

[0052] <Composition 12> The inkjet print head according to configuration 10 or 11, characterized in that the plurality of second adhesive layers are made of a material that cures at a lower temperature than the first adhesive layer.

[0053] <Composition 13> The inkjet print head according to configuration 10, characterized in that the plurality of second adhesive layers are installed along two opposing sides of the first substrate.

[0054] <Composition 14> The inkjet print head according to configuration 10, characterized in that the first substrate is a semiconductor substrate and the second substrate is a metal substrate.

[0055] <Composition 15> The inkjet print head according to configuration 10, characterized in that the length of the plurality of second adhesive layers is two-thirds or more of the length of the side edge of the first substrate adjacent to the plurality of second adhesive layers.

[0056] <Composition 16> The inkjet print head according to configuration 10, characterized in that the first adhesive layer is composed of a thermosetting adhesive.

Claims

1. A step of applying a first adhesive in a line to the bonding region of the first substrate to form a first adhesive layer, In the bonding region of the first substrate, a step of applying a second adhesive in a line shape to the line-shaped first adhesive layer at predetermined intervals, such that the line is intermittent, thereby forming a plurality of second adhesive layers having gaps due to the intermittences, A step of bonding the second substrate to the first substrate using the first adhesive layer and the plurality of second adhesive layers, and pressing the second substrate to the first substrate, The process involves curing the plurality of second adhesive layers on the first and second substrates to be pressed together, After the plurality of second adhesive layers have hardened, a step is made to harden the first adhesive layer. A joining method characterized by having the following features.

2. The joining method according to claim 1, characterized in that the length of each of the plurality of second adhesive layers is longer than the length of the gap.

3. The bonding method according to claim 1, characterized in that the plurality of second adhesive layers are installed along two opposing sides of the outer circumference of the bonding region.

4. The bonding method according to claim 1, characterized in that the first substrate is a semiconductor substrate and the second substrate is a metal substrate.

5. The bonding method according to claim 1, characterized in that the second substrate has an opening, and the inner circumference of the bonding region corresponds to the outer circumference of the opening.

6. The bonding method according to claim 1, characterized in that the length of the plurality of second adhesive layers is two-thirds or more of the length of the side edge of the first substrate adjacent to the plurality of second adhesive layers.

7. The bonding method according to claim 1, characterized in that the first adhesive layer is composed of a thermosetting adhesive.

8. The bonding method according to claim 7, characterized in that the plurality of second adhesive layers are made of a material that hardens at a lower temperature than the first adhesive layer.

9. The first substrate and the second substrate are joined together, A first adhesive layer formed in a line shape between the first substrate and the second substrate by a first adhesive, A plurality of second adhesive layers are formed by a second adhesive, adjacent to the aforementioned linear first adhesive layer, and are linear in shape with gaps between the lines. A joint characterized by having the following features.

10. The first substrate and the second substrate are joined together, A first adhesive layer formed in a line shape between the first substrate and the second substrate by a first adhesive, Adjacent to the aforementioned linear first adhesive layer are a plurality of linear second adhesive layers formed by a second adhesive, which are linear in shape and have gaps between them, A discharge tip installed on the first substrate, covered by the second substrate, and having a discharge nozzle, wherein the discharge nozzle is surrounded by an opening in the second substrate and exposed from the opening, An inkjet printhead characterized by having the following features.

11. The inkjet print head according to claim 10, characterized in that the length of the plurality of second adhesive layers is longer than the length of the gap.

12. The inkjet print head according to claim 10 or 11, characterized in that the plurality of second adhesive layers are made of a material that cures at a lower temperature than the first adhesive layer.

13. The inkjet print head according to claim 10, characterized in that the plurality of second adhesive layers are installed along two opposing sides of the first substrate.

14. The inkjet print head according to claim 10, characterized in that the first substrate is a semiconductor substrate and the second substrate is a metal substrate.

15. The inkjet print head according to claim 10, characterized in that the length of the plurality of second adhesive layers is two-thirds or more of the length of the side edge of the first substrate adjacent to the plurality of second adhesive layers.

16. The inkjet print head according to claim 10, characterized in that the first adhesive layer is composed of a thermosetting adhesive.

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