JP2014151561A - Liquid discharge head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge head which inhibits a lead for connecting a recording element substrate with an electric wiring board from contacting with the recording element substrate in an area other than an electric connection part.SOLUTION: A liquid discharge head 20 of the invention includes: a recording element substrate 17 which discharges an ink from a discharge port 4; and an electric wiring board 10 which is disposed so as to enclose the recording element substrate 17 and is electrically connected with the recording element substrate 17. At least one electric connection part 19 is provided at the recording element substrate 17. An insulation protrusion 5 made of an insulation material is provided between an edge of the recording element substrate 17 and the electric connection part 19. A lead 9 which electrically connects the electric connection part 19 with the electric wiring board 10 is provided so as to pass on the insulation protrusion 5.

Description

  The present invention relates to a liquid discharge head, and more particularly to a liquid discharge head that performs recording on a recording medium by discharging ink by an inkjet method.

  The ink jet recording apparatus is a so-called non-impact recording type recording apparatus. An ink jet recording apparatus is capable of performing high speed recording and recording on various recording media, and is widely employed as an apparatus that bears a recording mechanism such as a printer, a word processor, a facsimile machine, and a copying machine. As a typical recording method in an ink jet recording apparatus, there is known a method in which ink is heated by an electrothermal conversion element, ink is discharged from a minute discharge port by the action of film boiling, and recording is performed on a recording medium. ing. In order to perform such a recording method, an ink jet type liquid discharge head, a so-called ink jet recording head is used. The ink jet recording head is provided with a nozzle that forms droplets, a pressurizing chamber that communicates with the nozzle and pressurizes ink, and an electrothermal conversion element provided in the pressurizing chamber. Then, by applying an electrical pulse as a recording signal to the electrothermal conversion element, thermal energy is applied to the ink adjacent to the electrothermal conversion element, and ink is ejected to the recording medium through the ejection port at the nozzle tip by foaming. .

  In recent years, the need for high speed and high image quality is increasing day by day for ink jet recording apparatuses, and the density and length of ink jet recording heads are increasing. In order to achieve high image quality, it is necessary to reduce the interval between the ejection port from which ink is ejected and the recording medium in order to stably reach the recording medium with small droplets of ink. The ink jet recording head includes a recording element substrate and a flexible film wiring substrate (electric wiring substrate). Then, an electrical connection portion composed of an Au bonding pad of the recording element substrate, a bump thereon, and a flexible film wiring substrate disposed so as to surround the recording element substrate are connected by leads. For this reason, when the interval between the recording element substrate and the recording medium is reduced, an external force (for example, contact with the recording medium) or the like may be applied directly or indirectly to the lead, and the lead may be bent. In this case, there arises a problem that the lead comes into contact with the end portion of the recording element substrate to cause a short circuit.

  An example of a method for suppressing the contact between the lead and the end portion of the recording element substrate, which occurs when the lead is bent by an external force or the like, is disclosed in Patent Document 1. In this method, the contact between the end portion of the recording element substrate and the lead is suppressed by chamfering the end portion of the recording element substrate with a dicing blade.

  In addition, in the method disclosed in Patent Document 2, by forming a resin film in a boundary region for separating and cutting recording element substrates (semiconductor chips) formed on a semiconductor wafer, after cutting the semiconductor wafer, A resin film is formed on the end of the recording element substrate. Since this resin film becomes a protective film, even when the lead is bent due to an external force or the like, the lead is prevented from coming into direct contact with the end of the recording element substrate.

JP 2004-237528 A JP 2002-43356 A

  In the method disclosed in Patent Document 1, when the lead is bent by an external force by chamfering the end of the recording element substrate, the lead contacts the end of the recording element substrate as compared to the recording element substrate that is not chamfered. It becomes difficult to do. However, when the surface of the flexible film wiring substrate is positioned below the surface of the recording element substrate that has been chamfered, if the lead is bent by an external force, the recording element substrate that has been chamfered even if the lead is chamfered It becomes easy to contact the end of the wire, and there is a concern of short circuit.

  Further, in the method disclosed in Patent Document 2, when a resin film as a protective film is formed in a boundary region where the recording element substrate is separated and cut, it is possible to suppress a short circuit even when the lead is bent by an external force. However, when the semiconductor wafer is cut by dicing, fine resin generated from the resin film in the dicing street area adheres to the recording element substrate, the resin film in the dicing street area peels off, the blade is clogged, etc. Concerned.

  Accordingly, the present invention has been made in view of the above-described problems, and can prevent a lead connecting a recording element substrate and an electric wiring substrate from coming into contact with the recording element substrate other than an electrical connection portion. The object is to provide a head.

  The liquid ejection head of the present invention includes a recording element substrate that ejects ink from an ejection port, and an electric wiring substrate that is disposed so as to surround the recording element substrate and is electrically connected to the recording element substrate. The recording element substrate is provided with at least one electrical connection portion, and an insulating protrusion made of an insulating material is provided between the edge of the recording element substrate and the electrical connection portion. A lead for electrically connecting the two is provided so as to pass over the insulating protrusion.

  According to the present invention, the contact between the lead and the recording element substrate other than the electrical connection portion can be suppressed by the insulating protrusion formed on the recording element substrate. Accordingly, the interval between the liquid discharge head and the recording medium can be reduced, so that high-quality recording can be obtained, and a highly reliable liquid discharge head can be provided.

1 is a perspective view of a liquid discharge head according to a first embodiment of the present invention. It is the schematic of the AA 'cross section of FIG. It is the expansion schematic of the X section of FIG. 2, (a) is sectional drawing, (b) is a top view. FIG. 6 is a cross-sectional view of the vicinity of an end portion in a longitudinal direction of a recording element substrate of a conventional liquid discharge head. It is sectional drawing which shows the manufacturing process of the liquid discharge head by Embodiment 1 of this invention. FIG. 6 is a cross-sectional view of the vicinity of an end in a longitudinal direction of a recording element substrate of a liquid ejection head according to Embodiment 2 of the present invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the same number is attached | subjected to the structure which has the same function in an accompanying drawing, and the description may be abbreviate | omitted.

(Embodiment 1)
FIG. 1 is a perspective view of Embodiment 1 of the liquid discharge head of the present invention, and is a view seen through a lead sealing material 12 for explaining an electrical connection portion. FIG. 2 is a schematic view of a cross section AA ′ of the liquid discharge head shown in FIG. 3A and 3B are enlarged schematic views of a portion X in FIG. 2, in which FIG. 3A is a cross-sectional view and FIG. 3B is a plan view. FIG. 4 is a cross-sectional view of the vicinity of an end portion in the longitudinal direction of a recording element substrate of a conventional liquid discharge head. 3 and 4 omit the support substrate sealing material and the lead sealing material in order to explain the electrical connection between the recording element substrate and the flexible film wiring substrate.

  The liquid discharge head 20 of the present invention is, for example, an ink jet recording head. The ink is heated by an electrothermal conversion element in accordance with an electric signal, and the ink is discharged from a minute discharge port by the action of film boiling to form a recording medium. It is for recording. The liquid discharge head 20 includes a recording element substrate 17, a base plate 13, and a flexible film wiring substrate (electric wiring substrate) 10. The recording element substrate 17 includes a support substrate 1 and an orifice plate 3 disposed on the support substrate 1. An ink supply port 7 that supplies ink from an ink tank (not shown) to the ejection port 4 is formed in the support substrate 1 along the longitudinal direction. In the orifice plate 3, ejection ports 4 for ejecting ink are formed at a predetermined pitch along the ink supply ports 7 in the longitudinal direction.

  On the support substrate 1, ejection energy generating elements (electrothermal conversion elements (not shown)) that generate ejection energy (thermal energy) for ejecting ink are arranged so as to correspond to the ejection ports 4. A wiring (not shown) for supplying electric power to the electrothermal transducer is disposed on the support substrate 1, and a plurality of electrode pads below the Au bonding pads 6 at both ends in the longitudinal direction of the support substrate 1. (Not shown).

  An adhesion improving layer 2 is interposed between the orifice plate 3 and the support substrate 1. Further, at least the longitudinal edge 21 of the support substrate 1 is chamfered or stepped. In this embodiment, a case where chamfering is performed will be described. An insulating protrusion 5 made of an insulating material such as resin is formed between the longitudinal edge 21 of the support substrate 1 and the Au bonding pad 6. The insulating protrusion 5 is located at least immediately below the bump 9 formed on the Au bonding pad 6 and the lead 9 that is electrically bonded to the flexible film wiring substrate 10 described later. Therefore, the electrical connection portion 19 is formed by the Au bonding pad 6 and the bump 8. The insulating protrusions 5 may be provided so as to correspond to the respective electrical connection portions 19, and may extend in a strip shape along the aligned electrical connection portions 19, that is, along the edge of the support substrate 1. Good. In each figure, the insulation protrusion 5 extended in strip shape is shown.

  A recess is formed in the base plate 13, and a recording element substrate 17 is disposed in the recess. An ink supply port 14 is also provided in the base plate 13 so as to communicate with the ink supply port 7 of the support substrate 1. The base plate 13 and the recording element substrate 17 are bonded with an adhesive. On the base plate 13, the flexible film wiring substrate 10 is disposed in a portion that is not a recess so as to surround the recording element substrate 17. As described above, the flexible film wiring substrate 10 and the bumps 8 on the support substrate 1 are coupled by the leads 9.

  As shown in FIG. 4, conventionally, an Au bonding pad 6 and bumps 8 are formed on electrode pads (not shown) at both ends in the longitudinal direction of the support substrate 1. By connecting the bumps 8 and the flexible film wiring substrate 10 with the leads 9, the ink can be heated by the electrothermal conversion element in accordance with the electric signal, and the ink can be discharged from the discharge port 4. However, when the lead 9 is bent by an external force or the like as shown by a broken line in FIG. 4, the lead 9 comes into contact with the end portion (end portion of the support substrate 1) of the recording element substrate 17 and short-circuits.

  In the case of the present invention, since the insulating protrusion 5 is provided immediately below the lead 9, the contact between the lead 9 and the support substrate 1 can be suppressed. As shown in FIG. 3, the height h1 of the orifice plate 3 and The relationship of the height h2 of the insulating protrusion 5 from the surface of the support substrate 1 is h1 ≧ h2. That is, the height of the orifice plate 3 is the same as the height of the insulating protrusion 5 or higher than the height of the insulating protrusion 5. By satisfying such a relationship, the lead 9 does not protrude to the opposite side of the support substrate 1 from the orifice plate 3, and it is possible to suppress the external force from the recording medium or the like.

  The ink splashed from the ejection port 4 or the ink rebounded from the recording medium at the time of ink ejection is applied to the wiring on the support substrate 1, the electrical connection portion 19, the electrode pad (not shown), or the joint portion between the lead 9 and the flexible film wiring substrate 10. There is a possibility of adhesion. This adhesion of ink can corrode them. Therefore, for example, a resin material is applied using a dispenser and cured by heat to form the support substrate sealing material 11, the Au bonding pad 6, the bump 8, and the lead 9 so as to cover the lead 9. To do.

  In the liquid discharge head 20 configured as described above, the insulating projection 5 having insulating properties is provided between the lead 9 and the end of the recording element substrate 17 (end of the support substrate 1). The lead 9 does not come into contact with the end portion of the support substrate 1. Conventionally, in order to avoid contact between the end of the recording element substrate and the lead, there is a limit to reducing the distance from the bottom surface of the concave portion of the base plate to the flexible film wiring substrate. However, in the present invention, the contact between the lead 9 and the end of the recording element substrate 17 can be avoided by the insulating protrusion 5, so that the distance from the bottom surface of the recess of the base plate 13 to the flexible film wiring substrate 10 can be reduced. As a result, the distance between the bottom surface of the recess of the base plate 13 and the surface of the lead sealing material 12 can also be reduced.

  For these reasons, even if the distance between the liquid discharge head 20 and the recording medium is reduced, the lead 9 is difficult to receive external force and is difficult to contact the support substrate 1. Can be made smaller.

  The insulating protrusion 5 is preferably formed of the same insulating material as that of the orifice plate 3. Therefore, the insulating protrusion 5 and the orifice plate 3 can be formed simultaneously by photolithography, which is advantageous in terms of cost and manufacturing tact. Note that the same insulating material means that, for example, the insulating protrusion 5 and the orifice plate 3 are both formed of SiN. The molecular weight does not necessarily have to be exactly the same.

  Further, since the edge 21 in the longitudinal direction of the support substrate 1 is chamfered, it is difficult to contact the support substrate 1 even if the lead 9 is deformed. The insulating protrusion 5 may or may not overlap with the chamfered portion.

  From the above, in the recording apparatus equipped with the liquid ejection head 20 of the present invention, the reliability is high, the interval between the ejection port 4 from which ink is ejected and the recording medium can be reduced, and high-quality recording is possible. Become.

  Next, a method for manufacturing the recording element substrate 17 in the liquid discharge head 20 of the present invention will be described with reference to FIG. Since the recording element substrate 17 of the present invention can be implemented by a general method for manufacturing an ink jet recording head, only typical manufacturing steps will be described.

  First, as shown in FIG. 5A, a positive photosensitive cyclized rubber 15 is formed as an etching protective film on a support substrate 1 provided with an electrothermal conversion element and an electrode pad (not shown) at predetermined positions. Apply by spin coating. The film thickness of the positive photosensitive cyclized rubber 15 is not particularly limited as long as it is a film thickness remaining on the support substrate 1 after etching. Next, as shown in FIG. 5B, exposure and development are selectively performed on the portion of the completed recording element substrate 17 that becomes the edge 21 in the longitudinal direction of the support substrate 1.

  Then, as shown in FIG. 5 (c), V-grooves are formed by crystal anisotropic etching in the portions exposed and developed in FIG. 5 (b), and the support substrate 1 is shown in FIG. 5 (d). The positive type photosensitive cyclized rubber 15 is removed. At the time of etching, the V groove is opened at an angle of, for example, 54.7 °.

  Next, as shown in FIG. 5E, an Au bonding pad 6 is formed on the electrode pad at the end in the longitudinal direction of the support substrate 1.

  Next, as shown in FIG. 5 (f), the adhesion improving layer 2 is applied on the support substrate 1 by spin coating, and then, as shown in FIG. 5 (g), a positive photosensitive resist 16 is used as an etching protective film. Is applied by spin coating, and selectively exposed and developed as shown in FIG. The film thickness of the positive photosensitive resist 16 as an etching protective film may be 5 μm or more. For example, IP5700 (manufactured by Tokyo Ohka Co., Ltd.) can be used.

  Next, as shown in FIG. 5 (i), the adhesion improving layer 2 in the portion where the positive photosensitive resist 16 is selectively exposed and developed is etched by dry etching, as shown in FIG. 5 (j). The positive photosensitive resist 16 on the support substrate 1 is removed.

  Next, as shown in FIG. 5 (k), a negative photosensitive resist 18 is applied by a spin coating method, and the portion excluding the portion that becomes the orifice plate 3 and the insulating protrusion 5 as shown in FIG. 5 (l). Then, exposure and development are performed on a portion to be the discharge port 4 (not shown in FIG. 5L). Next, as shown in FIG. 5 (m), the recording element substrate 17 is cut along dicing streets to form a chip. In addition, since the space between the insulating protrusions 5 formed in the step shown in FIG. 5L is made larger than the dicing street width through which the dicing blade passes, the dicing blade does not touch the insulating protrusion 5 at the time of cutting. .

  By manufacturing the liquid discharge head 20 so as to include the steps described above, the liquid discharge head 20 of the present invention can be obtained.

(Embodiment 2)
A liquid discharge head according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a cross-sectional view of the vicinity of the end in the longitudinal direction of the recording element substrate 17 of the liquid ejection head in the present embodiment. Note that the support substrate sealing material 11 and the lead sealing material 12 are omitted.

  In the present embodiment, at least the edge 21 in the longitudinal direction of the support substrate 1 has a stepped shape. This stepped step can be formed by laser or etching. In addition, the stepped portion and the insulating protrusion 5 may or may not overlap.

  Also in this embodiment, when the lead 9 is bent by an external force or the like, the insulating protrusion 5 suppresses the contact between the support substrate 1 and the lead, and the edge 21 in the longitudinal direction of the support substrate 1 is stepped. The lead 9 and the support substrate 1 are more difficult to contact.

DESCRIPTION OF SYMBOLS 1 Support substrate 3 Orifice plate 4 Discharge port 5 Insulation protrusion 9 Lead 10 Flexible film wiring board (electric wiring board)
17 Recording element substrate 19 Electrical connection 20 Liquid discharge head 21 Edge

Claims (7)

A liquid ejection head comprising: a recording element substrate that ejects ink from an ejection port; and an electric wiring substrate that is disposed so as to surround the recording element substrate and is electrically connected to the recording element substrate,
The recording element substrate is provided with at least one electrical connection,
Between the edge of the recording element substrate and the electrical connection portion, an insulating protrusion made of an insulating material is provided,
A liquid discharge head, wherein a lead for electrically connecting the electrical connection portion and the electrical wiring board is provided so as to pass over the insulating protrusion. The recording element substrate includes a support substrate provided with an ejection energy generating element that generates ejection energy for ejecting the ink by electricity supplied via the electrical wiring substrate, the lead, and the electrical connection portion; An orifice plate disposed so as not to overlap with the electrical connection portion and formed with the discharge port,
The liquid ejection head according to claim 1, wherein a height of the orifice plate is equal to or higher than a height of the insulating protrusion.   The liquid ejection head according to claim 2, wherein the orifice plate and the insulating protrusion are made of the same insulating material.   4. The liquid ejection head according to claim 1, wherein a plurality of the electrical connection portions are arranged along the edge, and the insulating protrusion extends in a band shape. 5.   5. The liquid ejection head according to claim 1, wherein the edge of the recording element substrate is chamfered or stepped. 6.   The liquid ejection head according to claim 5, wherein the chamfering angle is 54.7 °.   The liquid ejection head according to claim 5, wherein the chamfering or the stepped shape is formed by etching.

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