Recording element unit and method for manufacturing the recording element unit

Abstract

To provide a recording element unit of low cost and high electrical reliability.SOLUTION: A recording element unit comprises a recording element substrate 10, an electric wiring member 20, a first electrode pad 11, and a second electrode pad 21, and a wire 30 for connecting the first electrode pad 11 with the second electrode pad 21 and is characterized in that the wire 30 has a plurality of flexure points bending in a wire drawing direction between a first junction B1 and a second junction B2, which are a first flexure point 301 in which the height from the first junction B1 is 100 μm or more and 200 μm or less, a second flexure point 302 in which the distance from the first flexure point 301 is 100 μm or more and 270 μm or less in a horizontal direction, and a third flexure point 303 in which the distance is located within 150 μm from the intermediate point between the first electrode pad 11 and the second electrode pad 21 in a horizontal direction.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a recording element unit and a method for manufacturing the recording element unit.

Background Art

[0002] An inkjet printer is an output device that forms characters and images by ejecting minute ink from an inkjet recording head, and is used in a wide range of applications such as home use, office use, and industrial use. The inkjet recording head is formed by accurately adhering a recording element unit to a support member connected to an ink supply means. The recording element unit includes a recording element substrate formed with a plurality of ejection energy generation portions, an ink flow path, and ink ejection ports on a silicon substrate, and a wiring substrate having an ejection signal output portion such as a drive IC, and transmits an electrical signal from the printer main body to the recording element substrate. A configuration including is known.

[0003] Conventionally, wire bonding has been used as an electrical mounting technique for electrically connecting a recording element substrate and a wiring substrate. Since there is a possibility of causing problems such as insulation failure when the bonding wire contacts a peripheral member or an adjacent bonding wire and causes a short circuit, it is important to appropriately form the shape of the bonding wire in wire bonding. Patent Document 1 discloses a technique for forming a supporting wire loop and maintaining a desirable wire loop height in order to improve the electrical reliability of the device.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, inkjet recording heads have seen progress in shrinking the recording element substrate to reduce product costs and miniaturizing components to improve functionality, requiring even higher density in electrical mounting methods. However, in small devices, due to space limitations for support members, methods such as providing wire loops to support wires, as described above, cannot be adopted. Furthermore, methods that include support members increase manufacturing costs.

[0006] This invention has been made in view of the above problems, and aims to provide a low-cost, electrically reliable recording element unit. [Means for solving the problem]

[0007] To achieve the above objective, the recording element unit used in the liquid ejection head of the present invention is A recording element substrate having an energy discharge unit, a flow path, and a discharge port, An electrical wiring member having a semiconductor integrated circuit that generates an electrical signal for discharging liquid from the discharge port, A first electrode pad provided on either the recording element substrate or the electrical wiring member, and a second electrode pad provided on the other, A wire having one end connected to the first electrode pad at a first connection point and the other end connected to the second electrode pad at a second connection point, electrically connecting the first electrode pad and the second electrode pad, Equipped with, The wire has a plurality of bending points between the first connection point and the second connection point, where the extension direction of the wire bends, and in order from the first connection point, at least the first bending point and , including a second inflection point and a third inflection point, When H1 is the height of the first inflection point from the first connection point, L2 is the distance in the horizontal direction from the first inflection point to the second inflection point, and W3 is the distance in the horizontal direction from the midpoint between the first electrode pad and the second electrode pad to the third inflection point, the following relationships are satisfied: (1) 100 μm ≤ H1 ≤ 200 μm, (2) 100 μm ≤ L2 ≤ 270 μm, (3) W3 ≤ 150 μm. It is characterized by the following: Furthermore, the method for manufacturing the recording element unit used in the liquid ejection head of the present invention is as follows: A recording element substrate having an energy discharge portion, a flow path, and an outlet, An electrical wiring member having a semiconductor integrated circuit that generates an electrical signal for discharging liquid from the discharge port, A first electrode pad provided on either the recording element substrate or the electrical wiring member, and a second electrode pad provided on the other, A wire having multiple bending points, one end connected to a first connection point of the first electrode pad, and the other end connected to a second connection point of the second electrode pad, electrically connecting the first electrode pad and the second electrode pad, Equipped with, The wire has a plurality of bending points that bend in a direction toward the second connection point from the first connection point, A method for manufacturing a recording element unit, wherein the plurality of bending points include, in order of proximity to the first connection point in the extension direction of the wire, a first bending point having a height of 100 μm or more and 200 μm or less from the first connection point, a second bending point having a horizontal distance of 100 μm or more and 270 μm or less from the first bending point, and a third bending point located lower than the first bending point and within 150 μm in the horizontal direction from the midpoint between the first electrode pad and the second electrode pad, A step of connecting one end of the wire to the first connection point, A step of sequentially forming the first bend point, the second bend point, and the third bend point on the wire by capillary action, The steps include connecting the other end of the wire to the second connection point, It is characterized by containing [Effects of the Invention]

[0008] As described above, the present invention makes it possible to provide a recording element unit with low cost and electrical reliability. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of the recording element unit according to Example 1. [Figure 2] This is a schematic cross-sectional view showing a wire bonding method related to a comparative example. [Figure 3] This figure shows the electrical connection configuration using wires according to Example 1. [Figure 4] This figure shows the capillary operation of wire bonding according to Example 1. [Figure 5] This figure shows the electrical connection configuration using wires according to Example 2. [Figure 6] This is a diagram of the recording element unit according to Example 3. [Figure 7] This figure shows an electrical connection configuration using wires related to a modified example. [Modes for carrying out the invention]

[0010] The following describes, with reference to the drawings, exemplary embodiments for carrying out this disclosure. However, the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments should be appropriately modified depending on the configuration and various conditions of the apparatus to which the disclosure applies. In other words, the scope of this disclosure is not intended to be limited to the following embodiments.

[0011] The present invention relates to a recording element unit provided in a liquid ejection head that ejects a liquid onto a recording medium to perform recording or the like. The present invention can be preferably applied to, for example, a recording element unit of an inkjet head provided in an inkjet printer that performs recording by foaming a liquid such as ink using thermal energy. However, the recording element unit of the present invention is not limited to this, and can be applied to recording element units of various liquid ejection heads that eject a liquid using thermal energy.

[0012] (Example 1) <Schematic configuration of the recording element unit> The configuration of the recording element unit 1 according to Example 1 will be described using FIGS. 1(a) and (b). FIG. 1(a) is a perspective view of the recording element unit 1 according to Example 1. FIG. 1(b) is a split perspective view of the recording element unit 1.

[0013] The recording element unit 1 of the present embodiment includes a recording element substrate 10 for ejecting ink, an electrical wiring member 20 connected to the recording element substrate 10 and the printer main body, and a discharge port surface cover 40 adhered to the ink discharge port (not shown) side of the recording element substrate 10. In the present embodiment, the electrical wiring members 20 are provided side by side on each of both sides of the recording element substrate 10, and the recording element substrate 10 and the electrical wiring member 20 are placed on the discharge port surface cover 40. The recording element unit 1 is connected to a container for storing ink, and the inkjet recording head ejects ink when the ink supplied by the ink supply means is ejected from the ink discharge port (not shown) of the recording element unit. In the following description, the direction in which the recording element substrate 10 and the electrical wiring member 20 are placed on the discharge port surface cover 40 is defined as the height direction, and the direction parallel to the arrangement direction of the recording element substrate 10 and the electrical wiring member 20 or the placement surface of the discharge port surface cover 40 is defined as the horizontal direction. This is a term used for convenience on the premise of the manufacturing process, defining height and horizontal, and is by no means the same scale as the direction when the liquid ejection head or the recording element head is actually used.

[0014] The recording element substrate 10 has a plurality of electrode pads (hereinafter referred to as PADs) 11 as connection terminals, an ejection energy generation section (not shown) through which the PADs 11 are electrically connected, a plurality of ink ejection ports, and an ink flow path 12 communicating with the ink ejection ports. The ink ejection ports and the ink flow path 12 are arranged to form a plurality of rows on the flow path forming member 13. Furthermore, the PADs 11 are also arranged in the same direction as the ink flow path 12, and rows of PADs are formed adjacent to the flow path forming member 13. In this embodiment, with respect to the flow path forming member 13, one row of PADs is formed on each side of the side on which the electrical wiring member 20 is provided.

[0015] The recording element substrate 10 is manufactured using silicon processing technology. The recording element substrate 10 is formed by joining a wafer on which an ejection energy generation section and an electrode PAD 11 are formed with a wafer on which an ink ejection port and an ink flow path 12 are formed, and then dicing the wafer into individual pieces.

[0016] The electrical wiring member 20 includes a plurality of PADs 21 as connection terminals, a drive IC (semiconductor integrated circuit) 22 on which the PADs 21 are provided and which generates and outputs an electrical signal for ink ejection, and a heat insulating member 23 that supports the drive IC 22. The drive IC 22 is placed on the heat insulating member 23 to prevent the heat generated when the drive IC 22 generates heat from being transmitted to the recording element substrate 10 or the ink.

[0017] Multiple PADs 21 corresponding to multiple PADs 11 are arranged on the drive IC 22 electrically mounted on the electrical wiring member 20 connected to the printer body, forming a row of PADs arranged in the same direction and at the same intervals as the PAD row of PADs 11. In this embodiment, the electrical wiring member 20 uses a flexible wiring board with polyimide for the base film and cover film. Note that the electrical wiring member is not limited to the above configuration and can be appropriately selected to include printed circuit boards, etc.

[0018] In this embodiment, PAD21 is positioned higher than PAD11, and PAD11 and PAD21 are electrically connected by bonding wires (hereinafter referred to as wires) 30 formed by wire bonding. As described above, PAD11 and PAD21 each form a PAD row, and one PAD21 is connected to one PAD11. That is, the recording element unit 1 has multiple wires 30 connecting PAD11 and PAD21, arranged adjacent to each other in the direction of the PAD row arrangement. Since contact between adjacent wires 30 and short-circuiting would cause insulation failure, etc., the wires 30 are provided with a certain interval between them, similar to PAD11 and PAD21. In this embodiment, a φ18μm gold wire is used for the wire 30. However, the wire diameter and material are not limited to these and can be changed as appropriate considering strength, the positional relationship of each component, etc.

[0019] The recording element substrate 10 and the driver IC 22 are electrically connected by connecting PAD 11 and PAD 12 with wire 30. After the wire 30 is formed by wire bonding, the electrically connected PAD 11, 12 and wire 30 are covered and protected with a sealing material (not shown) to form the recording element unit 1.

[0020] The discharge port cover 40 is a plate-shaped member connected to the recording element substrate 10 and the electrical wiring member 20. The discharge port cover 40 is bonded to the surface of the recording element substrate 10 where the ink discharge port is provided, and is open to match the ink discharge port. In other words, the position of the electrical wiring member 20 relative to the recording element substrate 10 is fixed by the discharge port cover 40. In this embodiment, alumina is used as the material for the discharge port cover 40. However, the material and shape of the cover are not limited to these, and can be changed to other metal members as appropriate.

[0021] <Wire bonding> Before describing the shape of the wire 30 in this embodiment and its effects, a wire bonding method will be explained using a comparative example. Since the comparative example has the same configuration as in Example 1 except for the method of forming the wire 30 and its shape, the same reference numerals will be used for the same components as in Example 1, and their explanation will be omitted.

[0022] Figures 2(a) to 2(d) are schematic front views showing a wire bonding method according to a comparative example. The wire bonding process includes the steps of connecting one end of the wire to one PAD, imparting a bend to the wire, and connecting the other end of the wire to the other PAD. Figure 2(a) shows the state after wire bonding is completed and PAD11 and PAD21 are connected by the wire 30. Figure 2(b) shows the state after one end of the wire 30 is connected to PAD21 by the capillary 31 and the wire 30 has been given a bend. Figure 2(c) shows the state as the capillary 31 is driven down toward PAD11. Figure 2(d) shows the state just before the wire 30 is connected to PAD11.

[0023] As shown in Figure 2(a), the PAD21 and the drive IC22 are mounted on the heat insulating member 23, and a step is created between the PAD21 and the PAD11. In this configuration, a loop shape is formed on the wire 30 to prevent it from coming into contact with surrounding members such as the drive IC22 or adjacent wires 30. This loop shape is formed by the movement of the capillary 31, which imparts a bending tendency to the wire 30. The method of forming the wire 30 using the capillary 31 in a comparative example will be described in detail below.

[0024] In the formation of the wire 30, first, a ball bond, which will be one end of the wire 30, is formed on the PAD 21, which is the first electrode pad located on the upper side. Next, the capillary 31 moves and bends the wire 30, forming a loop shape. Figure 2(b) shows the wire with one end connected to the PAD 21 and the other end connected to the wire 30 to form a loop shape. Ya30 is shown.

[0025] Next, in order to connect the other end of the loop-shaped wire 30 to the second electrode pad PAD11 located on the lower side, the capillary 31 moves downward towards PAD11 as shown in Figure 2(c). Then, as shown in Figure 2(d), the capillary 31 moves even closer to PAD11, and when a second bond is formed on PAD11, PAD11 and PAD21 are electrically connected by the wire 30. During the downward driving process of the capillary 31 shown in Figures 2(c) and (d), the position of the wire 30 changes. At this time, the loop shape of the wire 30 may change due to the weight of the wire 30 and the movement of the capillary 31. If the bend in the wire 30 deforms and the loop shape collapses, the wire 30 may bend or tilt in an unintended direction, raising concerns about short circuits between wires 30 or contact between wires 30 and other components. However, since the degree of deformation of the loop shape varies depending on the positional relationship between PAD11 and PAD21, it is extremely difficult to precisely predict how much it will deform. To avoid contact between the wire 30 and other components, it is conceivable to create large gaps between the wire 30 and other components, and between adjacent wires 30, in advance to allow for large deformation of the loop shape. However, this is undesirable for miniaturizing the unit.

[0026] <Electrical connection configuration> Next, the electrical connection configuration of the recording element unit 1 using wires 30 according to this embodiment will be described using Figures 3(a) and 3(b). Figure 3(a) is a detailed front view showing part A of Figure 1(a), and shows the loop shape of the wires 30 connecting the recording element substrate 10 and the drive IC 22. Figure 3(b) is a schematic top view of the recording element unit 1, showing the mounted PAD row.

[0027] In this embodiment, the first connection point B1 between wire 30 and PAD 21 is located higher than the second connection point B2 between wire 30 and PAD 11. The horizontal distance L0 between the first connection point B1 and the second connection point B2 is 1000 μm, and the height difference H0 is 900 μm. In the horizontal direction perpendicular to the arrangement direction of the PAD row, the distance L1 from the end of the drive IC 22 to the end of PAD 21 is 100 μm. It is preferable that PAD 21 be positioned as close as possible to the end of the drive IC 22, taking into account manufacturing tolerances and other factors to prevent wire 30 from contacting the drive IC 22.

[0028] The wire 30 in this embodiment is formed in a loop shape having three bending points. As a result of diligent study, the inventors of the present invention have found that by imparting a bending tendency so that at least three bending points are formed at appropriate positions, the deformation resistance of the wire connecting the PADs is greatly improved. Here, a bending point is the base point of a bent portion into which the wire 30 is bent by the capillary action of wire bonding so that it becomes steeper from PAD 21 toward PAD 11. In the direction of extension of the wire 30, the wire 30 has a first bending point 301, a second bending point 302, and a third bending point 303 in order from the PAD 21 which is at a higher position.

[0029] The wire 30 first extends in a substantially vertical direction from the first connection point B1 to the first bending point 301. Then, the wire 30 extends in a substantially horizontal direction from the first bending point 301 to the second bending point 302, approaching the second connection point B2. Furthermore, the wire 30 extends in a downward inclination from the second bending point 302 through the third bending point 303 to the second connection point B2, with the angle relative to the horizontal direction becoming steeper at the third bending point 303.

[0030] The first bending point 301 is formed approximately directly above the first connection point B1, and the height H1 of the first bending point 301 from the first connection point B1 is 120 μm. A lower height H1 of the first bending point 301 results in less deformation after bending and also contributes to space saving of the recording element unit 1. However, if the height H1 of the first bending point 301 is too low, the wire 30 is more likely to come into contact with the edge of the drive IC 22, etc. Therefore, setting the height H1 to satisfy the relationship 100 μm ≤ H1 ≤ 200 μm is particularly effective in improving the deformation resistance of the wire 30 and saving space.

[0031] The second bending point 302 is at approximately the same height as the first bending point 301, and is located horizontally closer to the second connection point B2 than the first bending point 301. The horizontal distance L2 between the second bending point 302 and the first bending point 301 is 150 μm. A larger horizontal distance L2 makes it easier to prevent the wire 30 from contacting the edge of the drive IC 22, etc. However, if the horizontal distance L2 is too large, the deformation of the wire tends to increase. Therefore, setting the horizontal distance L2 to satisfy the relationship 100 μm ≤ L2 ≤ 270 μm is particularly effective in improving the deformation resistance of the wire 30.

[0032] By providing a first bending point 301 near the first connection point B1, and a second bending point 302 near the first bending point 301, the amount of deformation of the wire 30 during the capillary 31 driving process could be reduced. In particular, by appropriately forming bending points in the portion of the wire 30 where the distance between the wire 30 and the drive IC 22 tends to be small, deformation of the wire 30 can be suppressed and contact between the wire 30 and other components can be prevented.

[0033] The third bending point 303 is located between the second bending point 302 and the second connection point B2. The wire 30 extends downward from the second bending point 302 toward the second connection point B2, and the third bending point 303 is located below the first bending point 301 and the second bending point 302. In the horizontal direction, the third bending point 303 is located midway between the first connection point B1 and the second connection point B2, and the horizontal distance L3 between the third bending point 303 and the first connection point B1 or the second connection point B2 is 500 μm. For example, if the third bending point 303 is extremely close to the second connection point B2 than to the first connection point B1, the distance from the third bending point 303 to the first connection point B1 becomes longer, and therefore the amount of deformation of the wire 30 increases. Conversely, if the third bending point 303 is located extremely close to the first connection point B1 than to the second connection point B2, the distance from the third bending point 303 to the second connection point B2 becomes longer, resulting in a larger deformation of the wire 30. Therefore, it is desirable that the third bending point 303 be located near the midpoint between the first connection point B1 and the second connection point B2. Setting the horizontal distance W3 from the midpoint between the first connection point B1 and the second connection point B2 to the third bending point 303 to satisfy the relationship W3 ≤ 150 μm is particularly effective in improving the deformation resistance of the wire 30.

[0034] By providing a third bending point 303 near the horizontal midpoint between PAD11 and PAD21, deformation of the wire 30 between the second connection point B2 and the second bending point 302 can be particularly suppressed. Suppressing the deformation of the wire 30 in this section is effective in preventing contact between adjacent wires 30.

[0035] As described above, by providing multiple bending points in the wire, deformation of parts of the wire other than the bending points can be suppressed even when the wire bends during capillary firing, thus preventing the wire from losing its bending characteristics. In other words, even when there is a difference in height between the pads, it is possible to form a wire with a loop shape close to the design value without the need for jigs or other fixtures.

[0036] Furthermore, if the height difference H0 is extremely large relative to the horizontal distance L0, the wire bending during capillary firing will be excessive, leading to significant deformation of the wire's curvature and deformation of the wire at points other than the bending point. On the other hand, if PAD11 and PAD21 are configured to satisfy the relationship between the horizontal distance L0 and the height difference H0, 0 ≤ H0 / L0 ≤ 1.3, then arranging the bending points to satisfy the above relationship is effective in suppressing wire deformation. Here, H0 / L0 = 0 means that there is no height difference between the first connection point B1 and the second connection point B2, and that each connection point is at the same height. It means to place.

[0037] Furthermore, it is effective in suppressing wire deformation when the horizontal distance L0 between the first connection point B1 and the second connection point B2 is within the range of 900 μm ≤ L0 ≤ 1500 μm, and the height difference H0 is within the range of 200 μm ≤ H0 ≤ 1100 μm. This is because if the horizontal distance L0 or the height difference H0 is too large, the distance between the first connection point B1 and the second connection point B2 is too great, and even if a bend is provided, it may not be possible to completely suppress wire deformation.

[0038] As mentioned above, PAD11 and PAD21 are arranged at equal intervals, forming PAD row L1 as the first pad row and PAD row L2 as the second pad row. As shown in Figure 3(b), the width D1 in the arrangement direction of PAD11 is 57 μm, and the arrangement pitch P1 of PAD11 in PAD row L1 is 75 μm. The width of PAD21 in the arrangement direction is the same as that of PAD11, and the arrangement pitch of PAD row L2 is the same as that of PAD row L1. In other words, the wires 30 connecting PAD11 and PAD21 are also arranged at equal intervals in the arrangement direction, and the adjacent pitch of continuously adjacent wires 30 in the arrangement direction is 75 μm.

[0039] As in this embodiment, forming multiple bending points in a wire to avoid short circuits between adjacent wires and improve deformation resistance is particularly effective when the adjacent wire pitch is small. More specifically, it is effective when the pitch of the PADs in the alignment direction is 80 μm or less, or when the adjacent wire pitch is 80 μm or less. Furthermore, it is effective when using narrow PADs with a width of 60 μm or less in the alignment direction and arranging PADs and wires at high density.

[0040] Figure 4 shows the operation of the capillary 31 in wire bonding to form the wire 30 of this embodiment. In Figure 4, the trajectory C of the movement of the capillary 31 is shown by a dotted line. In wire bonding, first, one end of the wire 30 is connected to the PAD 21 to form a ball bond. After that, the capillary 31 operates to impart a bend to the wire 30. When imparting the bend, the capillary 31 moves downward and horizontally away from the PAD 11. In the bending process of this embodiment, this capillary operation is performed three times, and the first bending point 301, the second bending point 302, and the third bending point 303 are formed in order. After these bending processes are performed, the capillary 31 is driven down to the PAD 11, and the other end of the wire 30 is connected to the PAD 11.

[0041] Based on the above, according to this embodiment, even in small recording element units where it is difficult to provide wire support members, the deformation resistance of the wires can be improved and unintended deformation of the wires can be suppressed. As a result, even when wires are arranged at high density, contact between wires and contact between wires and other components can be prevented, and an electrically reliable recording element unit can be provided. Furthermore, since there is no need to provide support members or the like to restrict wire deformation, it leads to a reduction in manufacturing costs.

[0042] It should be noted that the arrangement of each component, the position of the bending points, and the manufacturing method are not necessarily limited to the above-described embodiment and can be changed as appropriate. For example, even when the height difference between the PADs is small or there is no height difference, forming the first and second bending points on the wire near the ball bond makes it possible to form the desired loop shape without disrupting the wire's natural curvature. Furthermore, by changing the position of the second bending point according to the distance between the end of the drive IC and the electrode PAD, edge contact of the bonding wire can be avoided. In addition, increasing the wire diameter can suppress wire deformation that occurs during capillary firing, while decreasing the wire diameter can increase the tolerance for wire bending after bonding. Moreover, a configuration in which a bending point different from the third bending point is provided between the second bending point and the second connection point is also possible.

[0043] (Example 2) Next, Example 2 of the present invention will be described. Example 2 differs from Example 1 in the arrangement configuration of PAD11 and PAD21. Components in Example 2 that are the same as those in Example 1 are denoted by the same reference numerals and their description is omitted. The characteristic configuration of Example 2 of the present invention will be described below using Figures 5(a) and (b).

[0044] In Embodiment 1, the PAD row L1 on the recording element substrate had PAD11 arranged in a single row, but in this embodiment, the PAD row L3 has PAD11 arranged in two rows and is taller. In this embodiment, the PAD11 are arranged in a staggered pattern so that they are alternating in the direction of arrangement. Furthermore, the PAD row L4 on the electrical wiring member is configured with PAD21 arranged in two rows so that they are alternating in the direction of arrangement, and the PAD21 are arranged in a staggered pattern. In describing the PAD11 below, the one closer to PAD21 will be referred to as PAD11a, and the one further from PAD21 as PAD11b, and the denominations a and b will be added to the end of the denominations as needed. Similarly, in describing the PAD21, the one closer to PAD11 will be referred to as PAD21a, and the one further from PAD11 as PAD21b, and the denominations a and b will be added to the end of the denominations as needed. PAD11a is electrically connected to PAD21a by wire 30a, and PAD11b is electrically connected to PAD21b by wire 30b.

[0045] Figure 5(a) is a detailed front view of the recording element unit according to this embodiment, showing the loop shape of the wire 30 connecting the recording element substrate 10 and the drive IC 22. Figure 5(b) is a detailed top view of the recording element unit according to this embodiment, showing the mounted PAD row.

[0046] The positional relationship between PAD11a and PAD21a and the positional relationship of wire 30a in this embodiment is the same as in Embodiment 1. That is, the horizontal distance L0a between the first connection point B1a of wire 30a and PAD21a and the second connection point B2a of wire 30a and PAD11a is 1000 μm, and the vertical distance (height difference) H0a is 900 μm. Also, in the horizontal direction perpendicular to the arrangement direction of the PAD row, the distance L1a from the end of drive IC22 to the end of PAD21a is 100 μm.

[0047] The wire 30a in this embodiment has a first bending point 301a, a second bending point 302a, and a third bending point 303a. The first bending point 301a is formed approximately directly above the first connection point B1a, and the height H1a of the first bending point 301a from the first connection point B1a is 120 μm. The second bending point 302a is located at approximately the same height as the first bending point 301a, and the horizontal distance L2a between the second bending point 302a and the first bending point 301a is 150 μm. In the horizontal direction, the third bending point 303a is located midway between the first connection point B1a and the second connection point B2a, and the horizontal distance L3a between the third bending point 303a and the first connection point B1a or the second connection point B2a is 500 μm.

[0048] Next, the electrical connection configuration using wire 30b connecting PAD11b and PAD21b will be described. The horizontal distance L0b between the first connection point B1b and the second connection point B2b is 1250 μm, and the vertical distance (height difference) H0b is 900 μm. In the horizontal direction perpendicular to the arrangement direction of the PAD row, the distance L1b from the end of the drive IC22 to the end of PAD21b is 225 μm.

[0049] Wire 30b is also formed in a loop shape with three bending points, similar to wire 30a, and has a first bending point 301b, a second bending point 302b, and a third bending point 303b. The first bending point 301b is formed approximately directly above the first connection point B1b, and the height H1b of the first bending point 301b from the first connection point B1b is 180 μm. That is, the height H1b is in the range of 100 μm or more and 200 μm or less, satisfying the relational expression shown in Example 1. The second bending point 302b is located at approximately the same height as the first bending point 301b, and the horizontal distance L2b between the second bending point 302b and the first bending point 301b is 270 μm. That is, the horizontal distance L2b is between 100 μm and 270 μm, satisfying the relationship shown in Example 1. In the horizontal direction, the third bending point 303b is located midway between the first connection point B1b and the second connection point B2b, and the horizontal distance L3b between the third bending point 303b and the first connection point B1b or the second connection point B2b is 625 μm. That is, in the horizontal direction, the third bending point 303b is within 150 μm of the midpoint between the first connection point B1b or the second connection point B2b. By forming a bend at the above position, the deformation resistance of the wire 30b can be improved in the same way as the wire 30a.

[0050] By forming wires 30a and 30b so that multiple bending points are appropriately positioned, deformation during capillary firing can be suppressed, making it difficult for adjacent wires 30a and 30b to come into contact. Furthermore, when viewed from a direction perpendicular to the alignment direction, wire 30b is positioned above wire 30a. In other words, even if adjacent wires 30a and 30b in the alignment direction shift in the adjacent direction, contact is unlikely.

[0051] As mentioned above, PAD11a and PAD11b are arranged alternately at equal intervals, forming a two-row staggered PAD row L3. Similarly, PAD21a and PAD21b are arranged alternately at equal intervals, forming a two-row staggered PAD row L4. As shown in Figure 5(b), the width D1 in the arrangement direction of PAD11a and PAD11b is 57 μm. When viewed individually, the arrangement pitch P1 of PAD11a is 75 μm. On the other hand, the arrangement pitch P2 of PAD row L3, which is the interval between PAD11a and PAD11b, is half the arrangement pitch P1, which is 37.5 μm. In this way, by providing two types of wires with different loop shapes, the PAD rows can be arranged in a staggered pattern, allowing for higher density electrical connections. As a result, components can be made smaller.

[0052] (Example 3) Next, Embodiment 3 of the present invention will be described. Embodiment 3 differs from Embodiment 1 in that PAD 11 is located at a higher position than PAD 21. Components of Embodiment 3 that are the same as those in Embodiment 1 are denoted by the same reference numerals and their descriptions are omitted. Hereinafter, the characteristic configuration of Embodiment 3 of the present invention will be described using Figures 6(a) and (b). Figure 6(a) is a perspective view of the recording element unit 3 according to this embodiment. Figure 6(b) is a detailed front view showing part B of Figure 6(a).

[0053] In this embodiment, the electrical wiring member 20 is electrically connected to the recording element substrate 10, and the PAD 11 on the recording element substrate 10 is positioned higher than the PAD 21 on the electrical wiring member 20. That is, when forming the wire 60, one end is first connected to the PAD 11 as the first electrode pad, then a bending point is formed by capillary action, and the other end is connected to the PAD 21 as the second electrode pad. The driver IC is mounted in the electrical wiring that connects the electrical wiring member to the printer body.

[0054] In this embodiment, the wire 60 has a first bending point 601, a second bending point 602, and a third bending point 603, in order of proximity to the PAD 11, which is located at a higher position. In this embodiment, the first contact point B1 is formed on the PAD 11, and the second connection point B2 is formed on the PAD 2. In this way, even when the PAD 11 on the recording element substrate 10 is at a higher position than the PAD 21 on the electrical wiring member 20, deformation of the wire 60 can be suppressed by providing multiple bending points at appropriate positions. In particular, the effect of suppressing wire deformation can be further improved by determining the positions of each connection point and each bending point so as to satisfy the relational equations shown in the description of Embodiment 1.

[0055] As described above, this embodiment provides the same effects as in Embodiment 1, and because stitch bonds are not formed on the electrode pads on the silicon substrate, wire bonding can be performed without damaging the electrode pads or electrical wiring formed on the silicon substrate. The present invention is applicable in both cases: when the electrode pads on the recording element unit are at a higher position, and when the electrode pads on the drive IC (semiconductor integrated circuit) are at a higher position. It is also applicable when the two electrode pads are at the same height, as shown in the modified example in Figure 7. [Explanation of Symbols]

[0056] 10…Recording element substrate, 11…PAD (first electrode pad), 20…Electrical wiring component, 21…PAD (second electrode pad), 22…Drive IC (semiconductor integrated circuit), 30…Wire, 301…First bending point, 302…Second bending point, 303…Third bending point, B1…First connection point, B2…Second connection point

Claims

1. In a recording element unit used in a liquid ejection head, A recording element substrate having an energy discharge unit, a flow path, and a discharge port, An electrical wiring member having a semiconductor integrated circuit that generates an electrical signal for discharging liquid from the discharge port, A first electrode pad provided on either the recording element substrate or the electrical wiring member, and a second electrode pad provided on the other, A wire having one end connected to the first electrode pad at a first connection point and the other end connected to the second electrode pad at a second connection point, electrically connecting the first electrode pad and the second electrode pad, Equipped with, The wire has a plurality of bending points between the first connection point and the second connection point, the bending points of the wire's extension direction being bent, and in order from the first connection point, include at least a first bending point, a second bending point, and a third bending point. When H1 is the height of the first inflection point from the first connection point, L2 is the distance in the horizontal direction from the first inflection point to the second inflection point, and W3 is the distance in the horizontal direction from the midpoint between the first electrode pad and the second electrode pad to the third inflection point, the following relational equations (1), (2), and (3) are satisfied: A recording element unit characterized by the following features. 100 μm ≤ H1 ≤ 200 μm …(1) 100 μm ≤ L2 ≤ 270 μm …(2) W3 ≤ 150 μm … (3)

2. The aforementioned wire is It extends substantially in the height direction from the first connection point to the first bending point, It extends substantially horizontally from the first bending point to the second bending point, approaching the second connection point. The recording element unit according to claim 1, characterized in that it extends downward inclined from the second bending point through the third bending point to the second connection point, and the angle with respect to the horizontal direction changes more steeply at the third bending point.

3. The recording element unit according to claim 1 or 2, characterized in that the plurality of bending points are formed in the wire by capillary action.

4. The recording element unit according to any one of claims 1 to 3, characterized in that when the height difference between the first electrode pad and the second electrode pad is H0, and the horizontal distance from the first electrode pad to the second electrode pad is L0, the following relational expression (4) is satisfied. 0 ≤ H0 / L0 ≤ 1.3 …(4)

5. The first electrode pad is provided at a higher position than the second electrode pad. The above-mentioned height difference H0 satisfies the following relation (5): The recording element unit according to feature 4. 200 μm ≤ H0 ≤ 1000 μm …(5)

6. The recording element unit according to claim 5, characterized in that the horizontal distance L0 satisfies the following relational expression (6). 900 μm ≤ L0 ≤ 1500 μm …(6)

7. The electrical wiring member further includes a heat insulating member that supports the semiconductor integrated circuit from below. The first electrode pad is provided on the semiconductor integrated circuit, The second electrode pad is provided on the recording element substrate, A recording element unit according to any one of claims 1 to 6.

8. A first pad row formed by arranging a plurality of the first electrode pads at equal intervals in the arrangement direction, A second pad row is formed by arranging a plurality of the second electrode pads at equal intervals in the arrangement direction, with the same spacing as the first electrode pads. A recording element unit according to any one of claims 1 to 7, further comprising:

9. The first pad row is composed of the first electrode pads arranged in two rows so as to be alternating in the direction of the arrangement, The second row of pads is composed of the second electrode pads arranged in two rows so as to be alternating in the direction of the arrangement. The recording element unit according to feature 8.

10. The recording element unit according to claim 8 or 9, characterized in that the pitch of the first electrode pads in the first pad row in the arrangement direction is 80 μm or less.

11. The recording element unit according to any one of claims 8 to 10, characterized in that the width of the first electrode pad and the second electrode pad in the direction of arrangement is 60 μm or less.

12. The recording element unit according to any one of claims 8 to 11, characterized in that the adjacent pitch of adjacent wires in the arrangement direction is 80 μm or less.

13. In a method for manufacturing a recording element unit used in a liquid ejection head, A recording element substrate having an energy discharge unit, a flow path, and a discharge port, An electrical wiring member having a semiconductor integrated circuit that generates an electrical signal for discharging liquid from the discharge port, A first electrode pad provided on either the recording element substrate or the electrical wiring member, and a second electrode pad provided on the other, A wire having multiple bending points, one end connected to a first connection point of the first electrode pad, and the other end connected to a second connection point of the second electrode pad, electrically connecting the first electrode pad and the second electrode pad, Equipped with, A method for manufacturing a recording element unit, wherein the wire includes, in the extension direction of the wire, a first bending point located in order of proximity to the first connection point, with a height of 100 μm or more and 200 μm or less from the first connection point; a second bending point located at a horizontal distance of 100 μm or more and 270 μm or less from the first bending point; and a third bending point located at a lower position than the first bending point and at a distance of 150 μm or less from the midpoint between the first electrode pad and the second electrode pad in the horizontal direction. A step of connecting one end of the wire to the first connection point, A step of sequentially forming the first bend point, the second bend point, and the third bend point on the wire by capillary action, The steps include connecting the other end of the wire to the second connection point, A method for manufacturing a recording element unit, characterized by including the following:

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