Liquid ejection head and manufacturing method thereof

Abstract

To restrain reduction in yield, reduction in productivity and an increase in manufacturing cost by appropriately sealing an electric connection part of an element base board and a wiring base board.SOLUTION: A liquid discharge head includes an element base board 1 having a plurality of energy generating elements and a plurality of electrodes 7 and a wiring base board 3 having a plurality of electrode terminals 9 connected to the plurality of electrodes 7. The plurality of electrodes 7 and the plurality of electrode terminals 9 are both positioned side by side so as to form a row. The element base board 1 and the wiring base board 3 are overlaid on each other with the electrodes 7 facing the electrode terminals 9. A connection part where the plurality of electrodes 7 are connected with the plurality of electrode terminals 9 is enclosed by a resin layer 10. The resin layer 10 is covered with a sealing resin 11. The resin layer 10 is divided in a plurality of parts by a clearance 12 formed in a part between opposite ends of the electrode terminals 9 in the arrangement direction. The sealing resin 11 is filled in the inside of the clearance 12 of the resin layer 10.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a liquid ejection head and a manufacturing method thereof. [Background technology]

[0002] A liquid ejection head that ejects liquid to perform recording or the like generally has an element substrate that includes energy generating elements that generate ejection energy and electrodes that are electrically connected to the energy generating elements. A wiring substrate that includes electrode terminals that are connected to the electrodes of the element substrate and transmits electrical signals to be supplied to the energy generating elements is joined to the element substrate. The electrodes of the wiring substrate and the electrode terminals of the element substrate are connected using an anisotropic conductive film (ACF) or gold bumps formed on the electrodes. The connection portions via the bumps are protected by a non-conductive film (NCF) or a non-conductive paste (NCP). However, although ACF, NCF, and NCP protect the connection portions from moisture such as humidity, they have low resistance to liquid ink. Therefore, it is necessary to cover the periphery of the connection portions with a sealing resin that is ink-resistant. The gap between the wiring substrate and the element substrate is about 30 μm in the case of bonding using ACF, and about 60 μm in the case of bonding using bumps. As a sealing resin for filling this gap, an underfill material is generally used.

[0003] Patent Document 1 discloses a configuration in which the electrode terminals of the wiring board are disposed at positions set back from the ends of the wiring board by 0.05 mm to 1.0 mm. With this configuration, the gaps generated between the wiring board and the element board on the end side of the electrode terminals can be filled with sealing resin by utilizing capillary force to seal the connection parts. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-138520 A Summary of the Invention [Problem to be solved by the invention]

[0005] Usually, the end face of the wiring board connected to the element board of the liquid ejection head is located near the ejection port for ejecting the liquid, and it is difficult to apply the underfill material directly from the end face. Therefore, the underfill material is applied to the surface opposite to the connection part near the end of the wiring board, and the underfill material is made to go through the end of the wiring board and wrap around the gap between the element board and the wiring board by capillary force. However, as the liquid ejection head becomes larger and higher definition is achieved, the connection part becomes larger, and the underfill material that goes around through the end of the wiring board may not sufficiently fill the entire gap between the element board and the wiring board. In addition, the underfill material may enter the gap while taking in air bubbles. If these problems occur, it will lead to a decrease in yield and productivity, and will be a factor that will lead to an increase in manufacturing costs.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a liquid ejection head capable of satisfactorily sealing the electrical connection between an element substrate and a wiring substrate, and a method for manufacturing the same. [Means for solving the problem]

[0007] The liquid ejection head of the present invention comprises an element substrate having a plurality of energy generating elements that generate energy for ejecting liquid and a plurality of electrodes connected to the plurality of energy generating elements, and a wiring substrate having a plurality of electrode terminals connected to the plurality of electrodes, the plurality of electrodes and the plurality of electrode terminals are all arranged in a row, the element substrate and the wiring substrate are superimposed on each other with the electrodes and the electrode terminals facing each other, the connection portions where the plurality of electrodes and the plurality of electrode terminals are connected are surrounded by a resin layer, and the resin layer is covered with a sealing resin, the resin layer is divided into a plurality of portions by gaps provided in portions between both ends in the arrangement direction of the electrode terminals, and the gaps in the resin layer are filled with a sealing resin. The resin layer is non-conductive. It is characterized by: Effect of the Invention

[0008] According to the present invention, the electrical connection portion between the element substrate and the wiring substrate can be sealed satisfactorily. [Brief description of the drawings]

[0009] [Figure 1] 1A and 1B are a perspective view and a cross-sectional view taken along line AA of a liquid ejection head according to an embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view of a main part of the liquid ejection head shown in FIG. 1 taken along line BB. [Diagram 3] 2A is a plan view, a cross-sectional view taken along line AA, and a cross-sectional view taken along line BB of a joint portion between an element substrate and a wiring substrate of the liquid ejection head shown in FIG. 1, seen through the wiring substrate. [Figure 4] 2 is a perspective view showing a state in which an element substrate and an ejection port forming member are joined together in the manufacturing method of the liquid ejection head shown in FIG. [Diagram 5] 2 is a perspective view showing a wiring substrate forming step in the method for manufacturing the liquid ejection head shown in FIG. [Figure 6] 2A and 2B are a perspective view and a cross-sectional view taken along line AA, illustrating a bonding step between an element substrate and a wiring substrate in the manufacturing method of the liquid ejection head shown in FIG. [Figure 7] 2A to 2C are a plan view, a cross-sectional view along line AA, and a cross-sectional view along line BB, showing a bonding portion between an element substrate and a wiring substrate in a manufacturing method of the liquid ejection head shown in FIG. [Figure 8] 2A and 2B are a perspective view and a cross-sectional view taken along line AA, showing a sealing resin application step in the method for manufacturing the liquid ejection head shown in FIG. [Figure 9] 5A and 5B are a plan view and a cross-sectional view taken along line BB, showing a joint between an element substrate and a wiring substrate in a liquid ejection head according to a comparative example, seen through the wiring substrate. [Figure 10] 10A and 10B are a plan view and a cross-sectional view taken along line BB, showing a state in which a sealing resin has been applied to the liquid ejection head shown in FIG. 9, with a wiring board seen through. [Figure 11] 5A and 5B are a plan view and a cross-sectional view taken along line BB, showing a joint portion between an element substrate and a wiring substrate in a liquid ejection head according to a second embodiment of the present invention, with the wiring substrate seen through. [Figure 12] 11A and 11B are a plan view and a cross-sectional view taken along line BB, showing a joint between an element substrate and a wiring substrate in a liquid ejection head according to a third embodiment of the present invention, with the wiring substrate seen through. [Figure 13] 11A and 11B are a plan view, a cross-sectional view along line AA, and a cross-sectional view along line BB, showing a joint portion between an element substrate and a wiring substrate in a liquid ejection head according to a fourth embodiment of the present invention, with the wiring substrate seen through. [Figure 14] 14 is a plan view, a cross-sectional view taken along line AA, and a cross-sectional view taken along line BB, showing a state in which a sealing resin is applied to the liquid ejection head shown in FIG. 13, with a wiring board seen through. [Figure 15] 11A and 11B are a plan view and a cross-sectional view taken along line BB, showing a joint between an element substrate and a wiring substrate in a liquid ejection head according to a fifth embodiment of the present invention, with the wiring substrate seen through. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described. FIG. 1(a) is a perspective view of a liquid ejection head according to an embodiment of the present invention, and FIG. 1(b) is a cross-sectional view taken along line AA. FIG. 2 is a cross-sectional view taken along line BB, showing an enlarged view of the vicinity of the ejection ports of the liquid ejection head. In each drawing, line AA indicates a cutting line along the longitudinal direction of the wiring board, and line BB indicates a cutting line along the width direction of the wiring board. In the liquid ejection head according to this embodiment, an ejection port forming member 2 is laminated on one surface 1a of an element substrate 1, and one side of a wiring substrate 3 is fixed. The ejection port forming member 2 and the wiring substrate 3 are arranged at an interval. As shown in FIG. 2, a plurality of pressure chambers 4 are formed between the ejection port forming member 2 and the element substrate 1. On one surface 1a of the element substrate 1, energy generating elements 5 located in the respective pressure chambers 4 and wiring (not shown) electrically connected to the energy generating elements 5 are formed. Examples of the energy generating elements 5 include heating resistors and piezoelectric elements. The ejection port forming member 2 has ejection ports 6 that open from the pressure chambers 4 to the outside.

[0011] In this liquid ejection head, liquid is supplied to pressure chambers 4 from a flow path (not shown). When an electrical signal is supplied from wiring board 3 to energy generating elements 5 via wiring on element substrate 1, energy generating elements 5 are driven to generate energy for ejecting liquid. For example, if energy generating elements 5 are heating resistors, they generate thermal energy, which is applied to the liquid in pressure chambers 4 to heat and foam it. The liquid is ejected from ejection ports 6 to the outside by the foaming pressure.

[0012] The connection portion between the element substrate 1 and the wiring substrate 3 of this liquid ejection head will be described. FIG. 3(a) is a plan view showing the joint portion between the element substrate 1 and the wiring substrate 3, seen through the wiring substrate 3 shown by the two-dot chain line, FIG. 3(b) is a cross-sectional view along the line AA, and FIG. 3(c) is a cross-sectional view along the line BB. On one surface 1a of the element substrate 1, a plurality of electrodes 7 are arranged in a row near the outer periphery and at a position where they do not overlap with the ejection port forming member 2. The plurality of electrodes 7 are connected to the energy generating element 5 (see FIG. 2) via wiring (not shown). In the illustrated example, a gold bump 8 is provided on the electrode 7. On the other hand, a plurality of electrode terminals 9 are provided on the opposing surface 3a of the wiring substrate 3, which faces the one surface 1a of the element substrate 1. The plurality of electrode terminals 9 are arranged in a row, and are located at positions where they can face the plurality of electrodes 7 of the element substrate 1, respectively. The opposing surface 3a of the wiring board 3 is placed on one surface 1a of the element substrate 1, and each of the bumps 8 on the electrode 7 contacts each of the electrode terminals 9. The connection parts between the electrodes 7 and the bumps 8 and the electrode terminals 9 are surrounded by a resin layer 10. The outside of the resin layer 10 is further sealed by a sealing resin 11. The resin layer 10 surrounding the connection parts between the electrodes 7 and the bumps 8 and the electrode terminals 9 is made of, for example, NCF. The sealing resin 11 is made of an underfill material, for example, mainly composed of epoxy resin. The resin layer 10 is divided into a plurality of portions 10a, 10b by gaps 12. In other words, the entire connection parts between the electrodes 7 and the bumps 8 and the electrode terminals 9 are not surrounded by a continuous, integrated resin layer, but the connection parts are surrounded by the plurality of portions 10a, 10b of the resin layer 10, and gaps 12 are provided between adjacent portions of the resin layer 10. The sealing resin 11 that is positioned outside the resin layer 10 and seals it also penetrates into the gap 12 .

[0013] According to this configuration, the connection parts between the electrodes 7 and bumps 8 and the electrode terminals 9 are surrounded by the resin layer 10 and are protected from contact with moisture such as humidity. Furthermore, the resin layer 10 is sealed with the sealing resin 11 and is protected from contact with the liquid to be ejected (e.g., liquid ink). The sealing resin 11 is filled sufficiently to protect the connection parts and the resin layer 10, and good sealing is achieved without causing insufficient filling or the occurrence of internal voids. In this way, since there is no insufficient filling or voids, the manufacturing yield is high and the manufacturing cost can be kept low. Furthermore, good liquid ejection can be performed by the high-precision liquid ejection head, so that recording with high recording quality and high reliability can be performed.

[0014] A method for manufacturing a liquid ejection head according to this embodiment will be described. Fig. 4 shows an element substrate 1 and an ejection port forming member 2 before the wiring substrate is bonded. Fig. 5 shows a wiring substrate 3 before being bonded to the element substrate 1. Figs. 6 and 7 show a state in which the element substrate 1 and the ejection port forming member 2 are bonded to the wiring substrate 3. First, on one surface 1a of the element substrate 1 made of a silicon wafer, energy generating elements 5 (see FIG. 2) such as heating resistors and wiring (not shown) are patterned by photolithography. On one surface 1a of the element substrate 1 on which the energy generating elements 5 and wiring are patterned, a discharge port forming member 2 is formed by photosensitive resin. In the discharge port forming member 2, recesses or partitions for forming pressure chambers 4 and flow paths are formed. Furthermore, a discharge port 6 communicating with the pressure chamber 4 is formed in the discharge port forming member 2. Then, a liquid supply port (not shown) is formed on the other surface 1b of the element substrate by anisotropic etching or the like. Furthermore, as shown in FIG. 4(a), a plurality of electrodes 7 are formed by patterning plating near one side of one surface 1a of the element substrate 1 in plan view. The plurality of electrodes 7 are arranged so as to be parallel to the side surface of the element substrate 1. Thereafter, as shown in FIG. 4(b), a gold bump (stud bump) 8 is formed on the electrode 7 by wire bonding. In this embodiment, the height of the bumps 8 is in the range of 0.02 mm to 0.05 mm.

[0015] On the other hand, as shown in Figs. 5(a) and 5(b), a wiring board 3 for supplying an electric signal to the element substrate 1 is prepared. A plurality of electrode terminals 9 are formed near one side of the wiring board 3 in plan view. The electrode terminals 9 are provided in the same number as the electrodes 7 of the element substrate 1, and are arranged so that each of the electrode terminals 9 faces each of the electrodes 7. Therefore, the electrode terminals 9 have a planar shape and size similar to those of the electrodes 7, and are arranged at approximately the same pitch. As shown in Fig. 7(a), the electrode terminals 9 are arranged at a position retreated by a distance l from the end of the wiring board 3 in plan view. In this embodiment, the distance l is in the range of 0.05 mm to 1.0 mm. Next, as shown in Fig. 5(b), an NCF, which is a resin layer 10, is temporarily pressure-bonded to the position of the wiring board 3 where the electrode terminals 9 are provided. The resin layer 10 is composed of a plurality of portions 10a and 10b (two in the illustrated example) separated by a gap 12.

[0016] The electrodes 7 and the electrode terminals 9 are aligned so as to face each other via the bumps 8 and the NCF 10, and the wiring board 3 is placed on one surface 1a of the element substrate 1, as shown in Figs. 6(a) to 6(c). Then, the element substrate 1 and the wiring substrate 3 are pressed and bonded together. The electrode terminals 9 are set back from the end of the wiring substrate 3 by a distance l = 0.05 mm to 1.0 mm. Therefore, even if the resin layer 10 spreads during the thermocompression bonding between the element substrate 1 and the wiring substrate 3 as shown in Figs. 6(c), 7(a) to 7(c), it is prevented from protruding out from the end of the wiring substrate 3. In the case of bonding by NCF via the bumps 8 as in this embodiment, a gap of about 60 μm can be secured between the wiring substrate 3 and the element substrate 1.

[0017] In this way, after the wiring board 3 is bonded onto one surface 1a of the element substrate 1, as shown in FIG. 8, the sealing resin 11 is applied. FIG. 8(a) is a perspective view of the state in which the sealing resin is applied, and FIG. 8(b) is a cross-sectional view taken along line AA. Specifically, the laminate of the element substrate 1, the discharge port forming member 2, and the wiring substrate 3 is arranged so that the element substrate 1 is on top, and the needle 13 of the liquid constant quantity application device is arranged so that the tip portion is located on the wiring substrate 3 and in the vicinity of the side wall of the element substrate 1. While moving the needle 13 in the direction of the arrow in FIG. 8(a), a constant amount of the sealing resin 11 is continuously discharged from the opening at the tip of the needle 13, and applied so as to cover the resin layer 10. The sealing resin 11 spreads to cover the resin layer 10 and enters the gaps 12 (see FIG. 7(a)) of the resin layer 10. After entering the gap 12, the sealing resin 11 spreads left and right from the inside to the outside in the arrangement direction of the electrode terminals 9 (the same direction as the arrangement direction of the electrodes 7) after passing through the gap, covering the respective portions 10a and 10b of the resin layer 10. In this way, the liquid ejection head shown in FIG. 1 is formed.

[0018] In this embodiment, the sealing resin 11 sufficiently covers the entire resin layer 10 surrounding the connection between the electrode 7 of the element substrate 1 and the electrode terminal 9 of the wiring substrate 3, suppressing the occurrence of uncovered portions and the occurrence of voids due to the incorporation of air bubbles. For this purpose, in this embodiment, a gap 12 is provided in the intermediate portion (portion) between both ends of the resin layer 10 surrounding the connection in the arrangement direction of the electrode terminals 9, dividing the resin layer 10 into a plurality of portions 10a, 10b. The width of this gap is preferably 0.05 mm to 0.5 mm, and is large enough so that the gap 12 is not crushed and disappears even when the resin layer 10 is pressed and expanded when the element substrate 1 and the wiring substrate 3 are joined. The gap 12 has a function of promoting the inflow of the sealing resin 11. That is, the sealing resin 11 not only wraps around and fills from both sides of the wiring substrate by capillary action, but also advances from the intermediate portion in the arrangement direction of the electrode terminals 9 toward both sides by capillary action. Therefore, the sealing resin 11 is filled so as to cover the entire connecting portion and the resin layer 10. A sufficient amount of the sealing resin 11 is filled smoothly, so that the sealing resin 11 is prevented from trapping air bubbles. The width of the gap 12 is determined according to the viscosity of the sealing resin 11 and the size of the gap between the element substrate 1 and the wiring substrate 3. If the viscosity of the sealing resin 11 is 10 Pa·sec or less, the width of the gap 12 can be sufficiently filled with the sealing resin 11 if it is 0.03 mm or more.

[0019] The sealing resin 11 is preferably one with high fluidity, such as a flip chip underfill material used for bare chip mounting. For example, when a flip chip underfill material mainly composed of epoxy resin is applied to a predetermined position near the connection between the wiring board 3 and the element board 1, and then heated to, for example, 40°C to 90°C and left for about 3 to 10 minutes, the connection and the entire resin layer 10 are filled with the underfill material. As a result, a fillet 11a shown in FIG. 1(a) is formed on the outer periphery. Thereafter, the material is heated to 120°C to 150°C to be cured, whereby good sealing with the sealing resin 11 can be achieved in a short time. In addition, in this embodiment, the sealing resin 11 is filled within the lower side (opposing surface 3a) of the wiring board 3, so that no protrusions due to the sealing resin 11 are generated on the upper side of the wiring board 3. As a result, when this liquid ejection head is mounted on a recording device, the distance between the liquid ejection head and the recording medium can be set small, and recording accuracy can be improved. Also, since there are few protrusions and recesses on the ejection port side of the liquid ejection head, cleaning using a wiping blade can be performed well.

[0020] In the above description, as shown in Fig. 4, the ejection port forming member 2 is bonded to each element substrate 1, and the electrodes 7 and bumps 8 are formed. However, the ejection port forming member 2 may be bonded to multiple locations on a large-area silicon wafer, and the electrodes 7 and bumps 8 may be formed thereon, and the silicon wafer may then be cut by a dicing device or the like to separate the individual element substrates 1.

[0021] In the above example, gold bumps (ball electrodes) 8 are formed on the electrodes 7 of the element substrate 1, and are brought into contact with the electrode terminals 9 of the wiring substrate 3, and are surrounded and bonded with a resin layer 10 made of NCF or the like, but the present invention is not limited to this configuration. For example, instead of forming the bumps 8, ACF, which is the resin layer 10, can be temporarily bonded to the portions of the wiring substrate 3 where the electrode terminals 9 are formed. In this case, the element substrate 1 and the wiring substrate 3 can be fixed by placing the resin layer 10 made of ACF opposite the element substrate 1, aligning the positions of the electrodes 7 and the electrode terminals 9, bringing them into direct contact with each other, and heating and bonding them under pressure. The resin layer 10 is not limited to NCF, and NCP applied to the portions of the wiring substrate 3 where the electrode terminals 9 are formed can also be used as the resin layer 10. In this case, the element substrate 1 and the wiring substrate 3 can be fixed by placing the resin layer 10 made of NCP opposite the element substrate 1, aligning the positions of the electrodes 7 and the electrode terminals 9, and heating and bonding them under pressure. In this embodiment, the electrode terminals 9 are located at a position retreated from the end of the wiring board 3 by a distance l = 0.05 mm to 1.0 mm, so that the resin layer 10, which spreads due to the thermocompression bonding of the element substrate 1 and the wiring board 3, is prevented from protruding out from the end of the wiring board 3. In the case of bonding by NCF or NCP via the bumps 8, a gap of about 60 μm can be secured between the wiring board 3 and the element substrate 1. In addition, in the case of bonding by ACF without providing the bumps 8, a gap of about 30 μm can be secured between the wiring board 3 and the element substrate 1. EXAMPLES

[0022] Hereinafter, more specific examples of the liquid ejection head of the present invention will be described in comparison with comparative examples. Some of the descriptions of the same parts as those in the above-described embodiment of the present invention will be omitted. (Comparative Example) FIG. 9(a) shows a plan view of the joint between the element substrate 1 and the wiring substrate 3 of a comparative liquid ejection head having the same configuration as the conventional liquid ejection head, in which the wiring substrate 3 is seen through as shown by the two-dot chain line. FIG. 9(b) is a cross-sectional view taken along line BB. FIG. 10(a) is a plan view of the wiring substrate in which the sealing resin is applied to the liquid ejection head shown in FIG. 9, and FIG. 10(b) is a cross-sectional view taken along line BB. In the liquid ejection head of this comparative example, 70 electrode terminals 9 are provided on the wiring substrate 3 having a width of 15 mm. The electrode terminals 9 are arranged in a row at a position 0.2 mm back from the end of the wiring substrate 3. In this comparative example, no gap 12 is provided in the resin layer 10. The sealing resin 11 covering the resin layer 10 only wraps around both ends of the wiring substrate 3, so there is a possibility that it is not sufficiently supplied to the middle of the arrangement direction of the electrode terminals 9. Even if the sealing resin 11 is an underfill material CV5350AS (product name) manufactured by Panasonic Corporation with a viscosity of 4 Pa·sec, and is heated to 40°C to 90°C after application to temporarily increase the fluidity, it is difficult for the sealing resin 11 to wrap around the entire resin layer 10. There is a risk that the sealing resin 11 starts hardening while flowing, resulting in a region 14 where the resin does not wrap around, or a gap 15 due to the incorporation of air bubbles. In contrast, if an attempt is made to deal with this by increasing the amount of sealing resin 11 applied, the resin will excessively collect at both ends of the wiring board 3, and will flow to the discharge port forming member 2 before wrapping around the periphery of the resin layer 10, causing problems such as blocking the discharge port 6. Ultimately, in this comparative example, there is a possibility that the resin layer 10 cannot be easily and reliably and satisfactorily covered with the sealing resin 11.

[0023] Example 1 Example 1 of the present invention based on the above-mentioned embodiment will be described with reference to Figs. 1 and 7. In this example, a wiring board 3 having a width of 15 mm and 70 electrode terminals 9 arranged at a position 0.2 mm back from the end is used. The resin layer 10 of the wiring board 3 is made of NCF and is divided into two parts 10a and 10b by a gap 12 having a width of 0.05 mm at the middle part in the arrangement direction of the electrode terminals 9. Even after the resin layer 10 spreads due to the thermocompression bonding of the element board 1 and the wiring board 3, the gap 12 is secured and its width is 0.03 mm or more. The electrodes 7 of the element board 1 are arranged so as to overlap the electrode terminals 9 of the wiring board 3. In this example, an underfill material CV5350AS (product name) manufactured by Panasonic Corporation having a viscosity of 4 Pa·sec is used as the sealing resin 11. As in the above-described embodiment, the element substrate 1 and the wiring substrate 3 were bonded by thermocompression bonding, and then the sealing resin 11 was applied and left for 10 minutes while heated to 60° C., so that the sealing resin 11 spread over the entire connecting portion and the resin layer 10. Thereafter, the sealing resin 11 was cured by heating to 150° C. and left for 30 minutes, and the liquid ejection head shown in FIG. The sealing resin 11 is applied near the connection of the bonding surface between the wiring board 3 and the element substrate 1, as indicated by the arrow in FIG. 7(b). Then, as indicated by the arrow in FIG. 7(a), the sealing resin 11 flows around both ends of the wiring board 3 in the arrangement direction of the electrode terminals 9, and flows toward both ends from the gap 12 in the middle for promoting the flow of the sealing resin. The sealing resin 11 flows through the gap between the wiring board 3 and the element substrate 1 by capillary action, and is filled so as to surround the entire area of ​​the resin layer 10. According to this embodiment, even if the connection between the electrodes 7 and the electrode terminals 9 is provided over a wide area, the sealing resin 11 can be filled uniformly in a short time while suppressing the occurrence of unfilled portions and the inclusion of air bubbles.

[0024] Example 2 FIG. 11(a) shows a plan view of the joint between the element substrate 1 and the wiring substrate 3 of the liquid ejection head of the second embodiment of the present invention, with the wiring substrate 3 shown in the two-dot chain line seen through. FIG. 11(b) is a cross-sectional view taken along the line BB. In the liquid ejection head of this embodiment, at least one electrode terminal 9 (two electrode terminals in the example shown in FIG. 11) on each end of the wiring substrate 3 in the arrangement direction is located further back from the end of the wiring substrate 3 than the other electrode terminals 9. The end of the wiring substrate 3 referred to here is the end of the wiring substrate 3 that is close to the ejection port forming member 2 in the longitudinal direction (direction of line AA in FIG. 3). As an example, the recession distance of the electrode terminal 9 in the middle from the end of the wiring substrate 3 is 0.2 mm, while the recession distance of the electrode terminal 9 further back from the end is larger, 0.3 mm. In this embodiment as well, the electrodes 7 of the element substrate 1 are arranged at positions facing the electrode terminals 9 of the wiring substrate 3. In this way, the electrode terminals 9 on both ends of the wiring board 3 in the arrangement direction of the electrode terminals 9 are located further back than the other electrode terminals 9, so that the capillary force acting on the sealing resin 11 from both ends to the middle of the wiring board 3 becomes stronger. This, combined with the effect of promoting the inflow of the sealing resin by the gaps 12 provided in the resin layer 10 as described above, further shortens the filling time of the sealing resin 11. Furthermore, by moving some of the electrode terminals 9 back from the other electrode terminals 9, there is an effect that alignment with the electrodes 7 of the element substrate 1 is made easier. It is more preferable that, among the electrode terminals 9 of the wiring board 3, five or more electrode terminals 9 on both ends of the arrangement direction are located further back from the ends of the wiring board 3 than the other electrode terminals 9.

[0025] Example 3 FIG. 12(a) shows a plan view of the joint between the element substrate 1 and the wiring substrate 3 of the liquid ejection head of the third embodiment of the present invention, with the wiring substrate 3 shown in the two-dot chain line seen through. FIG. 12(b) is a cross-sectional view taken along the line BB. In the liquid ejection head of this embodiment, the electrode terminals 9 are located at positions further back from the end of the wiring substrate 3 than the other electrode terminals 9 at both ends and the middle part in the arrangement direction of the electrode terminals 9 of the wiring substrate 3. The end of the wiring substrate 3 referred to here is the end on the side close to the ejection port forming member 2 in the longitudinal direction (direction of line AA in FIG. 3) of the wiring substrate 3. That is, as in the second embodiment, at least one electrode terminal 9 on each end of the arrangement direction, preferably five or more (two each in the example shown in FIG. 12) are further back from the end of the wiring substrate 3. In addition, at least one electrode terminal 9 on each side of the gap 12 of the resin layer 10 at the middle part, preferably five or more (two each in the example shown in FIG. 12) are also further back from the end of the wiring substrate 3. The other electrode terminals 9 are set back by a distance of 0.2 mm from their ends, whereas the further setback electrode terminal 9 is set back by a distance of 0.3 mm from its end. Even in this configuration, the electrodes 7 of the element substrate 1 are disposed at positions facing the electrode terminals 9 of the wiring substrate 3, respectively. The same effect as in Example 2 is obtained. Furthermore, since the electrode terminals 9 located on both sides of the gap 12 in the resin layer 10 are set back further, the sealing resin 11 easily flows from the gap 12 toward both end sides, and the effect of promoting the inflow of the sealing resin is enhanced.

[0026] Example 4 FIG. 13(a) shows a plan view of the wiring board 3 shown by the two-dot chain line before the sealing resin is applied to the joint portion between the element substrate 1 and the wiring board 3 of the liquid ejection head of the fourth embodiment of the present invention. FIG. 13(b) shows a cross-sectional view along the line AA, and FIG. 13(c) shows a cross-sectional view along the line BB. FIG. 14(a) shows a plan view of the wiring board 3 shown by the two-dot chain line after the sealing resin is applied to the joint portion between the element substrate 1 and the wiring board 3 of the liquid ejection head of FIG. 13. FIG. 14(b) shows a cross-sectional view along the line AA, and FIG. 14(c) shows a cross-sectional view along the line BB. In the liquid ejection head of this embodiment, as in the third embodiment, there are electrode terminals 9 that are further back from the end of the wiring board 3 than the other electrode terminals 9 on both ends in the arrangement direction and on both sides of the gap 12 of the resin layer 10. The end of the wiring board 3 referred to here is the end on the side close to the ejection port forming member 2 in the longitudinal direction (direction of the line AA in FIG. 3) of the wiring board 3. The respective setback distances are 0.2 mm and 0.3 mm. The electrode terminals 9 of the wiring board 3 and the electrodes 7 of the element substrate 1 are connected using ACF as the resin layer 10. Before bonding the wiring board 3 and the element substrate 1, AFC is temporarily pressure-bonded to the positions where the electrode terminals 9 of the wiring board 3 are formed. At this time, the ACF can be attached with high precision using the electrode terminals 9 that are further setback at both ends in the arrangement direction and on both sides of the gap 12 as guides for alignment. This ensures that the gap 12 is secured. Thereafter, the electrode terminals 9 of the wiring board 3 and the electrodes 7 of the element substrate 1 are aligned, and heat and pressure bonding are performed to complete the bonding of the two substrates 1 and 3. As shown in FIG. 13(c), in the bonding using ACF, the electrodes 7 and the electrode terminals 9 come into direct contact with each other, and the gap between the element substrate 1 and the wiring board 3 after bonding is narrower than that in the bonding using the bumps 8 and NCF or NCP, and is about 30 μm. However, the ACF can be accurately aligned using the recessed electrode terminals 9, which has the great effect of easily and reliably securing a flow path for the sealing resin 11. In this embodiment as well, the sealing resin 11 flows smoothly from both ends in the arrangement direction and from the gap 12 in the middle, resulting in an effect of further shortening the filling time for the sealing resin 11.

[0027] Example 5 FIG. 15(a) shows a plan view of the wiring board 3 shown by the two-dot chain line before the sealing resin is applied to the joint portion between the element substrate 1 and the wiring board 3 of the liquid ejection head of the fifth embodiment of the present invention. FIG. 15(b) is a cross-sectional view taken along the line BB. In the liquid ejection head of this embodiment, as in the third embodiment, there are electrode terminals 9 on both ends in the arrangement direction and on both sides of the gap 12 in the resin layer 10, which are further back from the end of the wiring board 3 than the other electrode terminals 9. The end of the wiring board 3 here refers to the end on the side close to the ejection port forming member 2 in the longitudinal direction (the direction of line AA in FIG. 3) of the wiring board 3. In this embodiment, the electrode terminals 9 located on both sides of the gap 12 in the resin layer 10 are positioned at a large interval along the arrangement direction. In the third embodiment, the pitch of the multiple electrode terminals 9 in the row is not changed, including the gap 12 in the resin layer 10 and the position facing the periphery thereof. However, in this embodiment, the electrode terminals 9 are arranged at a pitch (for example, 0.2 mm) twice as long as the other positions at the position opposite the gap 12. In this embodiment, the NCF, which is the resin layer 10 divided into two parts 10a and 10b by the gap, is temporarily pressure-bonded to the wiring board 3, and then the electrodes 7 of the element board 1 and the electrode terminals 9 of the wiring board 3 are aligned and heated and pressed to bond the two boards 1 and 3. Since a wide gap is secured at the position opposite the gap 12 of the resin layer 10 in this embodiment, a sealing resin 11 having a relatively high viscosity can be used even in the bonding using the ACF, which has a narrow gap between the element board 1 and the wiring board 3, as the resin layer 10. For example, in this embodiment, the width of the gap 12 of the resin layer 10 after the heat and pressure bonding is secured to be 0.1 mm. In this configuration, the sealing resin (CV5420AR (product name) manufactured by Panasonic Corporation) having a viscosity of 30 Pa·sec can be filled well.

[0028] (Combination of Examples) As in each of the embodiments of the present invention described above, by combining the position of the electrode terminals 9 of the wiring board 3 with the type and position of the resin layer 10 used for bonding (NCF, NCP or ACF), it is possible to select and use the sealing resin 11 that is optimal for each configuration. In the present invention, the resin layer 10 may be divided into three or more parts. In that case, two or more gaps 12 are provided in the resin layer 10. [Explanation of symbols]

[0029] 1. Element substrate 3. Wiring board 7 electrodes 9 Electrode terminal 10 Resin layer 11 Sealing resin 12 Gap

Claims

1. an element substrate having a plurality of energy generating elements that generate energy for ejecting liquid and a plurality of electrodes connected to the plurality of energy generating elements; and a wiring substrate having a plurality of electrode terminals connected to the plurality of electrodes; The plurality of electrodes and the plurality of electrode terminals are arranged in a row, the element substrate and the wiring substrate are superimposed on each other with the electrodes and the electrode terminals facing each other, connection portions at which the electrodes and the electrode terminals are connected are surrounded by a resin layer, and the resin layer is covered with a sealing resin, the resin layer is divided into a plurality of parts by gaps provided between both ends of the resin layer in an arrangement direction of the electrode terminals, the gap in the resin layer is filled with the sealing resin, The liquid ejection head according to claim 1, wherein the resin layer is non-conductive.

2. 2. The liquid ejection head according to claim 1, further comprising an ejection port forming member disposed on the element substrate at a position not overlapping with the wiring substrate, the ejection port having an ejection port through which liquid is ejected when energy is applied from the energy generating element.

3. 3. The liquid ejection head according to claim 1, wherein some of the plurality of electrode terminals are set back from the end of the wiring substrate by a greater distance than the other electrode terminals.

4. 4. The liquid ejection head according to claim 3, wherein at least one electrode terminal located at each of both ends in the arrangement direction of the electrode terminals is an electrode terminal that is set back a large distance from an end of the wiring substrate.

5. 5. The liquid ejection head according to claim 3, wherein at least one electrode terminal located on each of both sides of the gap in the arrangement direction of the electrode terminals is an electrode terminal that is set back a large distance from an end of the wiring board.

6. The liquid ejection head according to claim 1 , wherein the pitch between adjacent electrode terminals sandwiching a position facing the gap among the plurality of electrode terminals is larger than the pitch between the other electrode terminals.

7. 7. The liquid ejection head according to claim 1, wherein the electrode and the electrode terminal face each other via a bump, and the resin layer is a non-conductive resin film or a non-conductive resin paste.

8. 8. The liquid ejection head according to claim 1, wherein the size of the gap in the direction in which the plurality of electrodes are arranged is 0.05 mm to 0.5 mm.

9. a step of bonding an element substrate having a plurality of energy generating elements that generate energy for ejecting liquid and a plurality of electrodes connected to the energy generating elements, and a wiring substrate having a plurality of electrode terminals connected to the electrodes, the step of surrounding a connection portion where the electrodes and the electrode terminals are connected with a resin layer in a state where the electrodes arranged in a row on the element substrate and the electrode terminals arranged in a row on the wiring substrate face each other, and bonding the element substrate and the wiring substrate; covering the resin layer with a sealing resin; the resin layer is divided into a plurality of parts by gaps provided between both ends of the resin layer in an arrangement direction of the electrode terminals, A method for manufacturing a liquid ejection head, characterized in that in the process of covering the resin layer with a sealing resin, the sealing resin is caused to wrap around the resin layer from both sides in the arrangement direction of the electrode terminals of the wiring board, pass through the gap between the both ends in the arrangement direction of the electrode terminals, and then flow toward the both ends, and then harden.

10. The method for manufacturing a liquid ejection head according to claim 9 , further comprising bonding the wiring substrate to which the resin layer has been temporarily pressure-bonded, to the element substrate.

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