JP2006198884A - Substrate for inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording head capable of exerting maximum performance of a heating resistor as well as realizing the high density of the heating resistors, and a substrate for the head. <P>SOLUTION: An insulation film made of an insulation material, a plurality of bubble-generating heating resistor arrays for generating necessary heat for generating bubbles in ink, a plurality of auxiliary heating resistor arrays for aiding the heating of the bubble-generating heating resistors, and a plurality of ink channel arrays communicating with ejection nozzles for ejecting ink are provided on a substrate to form the substrate for the inkjet head. The bubble-generating heating resistors, the auxiliary heating resistors therebelow with the insulation layer therebetween and wiring patterns therebelow with the insulation layer therebetween to be electrically connected to the heating resistors are provided to the substrate. A region of the bubble-generating heating resistors is placed at the outside of a wall section of an ink channel in the arrangement direction on a plumb line of the substrate and a region of the auxiliary heating resistors is overlapped with the wall section of the ink channel in the arrangement direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording head that performs recording by discharging ink, the head substrate, a method for manufacturing the substrate, an ink jet recording apparatus, and an ink jet discharging head substrate.

  The inkjet recording method disclosed in Patent Document 1 or Patent Document 2 is capable of high-speed, high-density, high-precision, high-quality recording, and is suitable for colorization and compactness. A recording head that uses this ink jet recording method and foams ink using thermal energy to eject the ink onto a recording medium has the same heating resistor for foaming the ink and wiring that electrically connects to the heating resistor. In general, the ink jet recording head substrate is formed on the substrate, and nozzles for discharging ink are formed on the substrate.

Various ideas have been made to increase the thermal energy efficiency. In Patent Document 3, an auxiliary heating heater is provided in addition to the foaming heater to improve the ink ejection efficiency at low temperatures.
U.S. Pat. No. 4,723,129 U.S. Pat. No. 4,740,796 Japanese Patent Laid-Open No. 10-774

  In addition, recently, the demand for high-quality recording has further increased, and the size of ink droplets has been steadily becoming smaller dots. At the same time, in order not to reduce the recording speed, the nozzles for these small dots have been increased in density. The need to place it came out. As a result, new problems have arisen to achieve high density nozzle placement and small dot ink drops.

  That is, when the heater for foaming is made smaller, the actual foaming area becomes smaller with respect to the heater size due to the heat escape in the lateral direction, and the foaming becomes unstable. This makes it impossible to reduce the heater size, resulting in difficult high-density nozzle placement.

  For example, when the nozzles are arranged at a pitch of 1200 dpi on one side, the distance between the nozzles is about 21 μm, and considering the nozzle wall width of 8 μm and the nozzle wall / heater misalignment of 3 μm, the heater size can be secured only 10 μm. When the heater size is 10 μm wide with respect to the nozzle row direction, heat is diffused in the area of about 3 μm around the heater, so that the substantial foaming area becomes about 4 μm wide, making foaming unstable and necessary. Discharge energy is also insufficient. Here, if the heater width region of 10 μm can be foamed, the foaming stability can be ensured. Therefore, if both ends of the heater are positioned under the nozzle wall, the width will be sufficiently large. This causes a problem that the nozzle wall portion in contact with the heater portion is deformed.

  As described above, as the heater size is reduced, expanding the substantial foaming region is an important issue for high-density nozzle arrangement.

  An object of the present invention is to solve the conventional problems and to provide a substrate for an ink jet discharge head that can fill a gap between a heater size limited by a nozzle wall and a substantial foaming region.

  In the inkjet recording head substrate of the present invention, a foaming heating resistor and an auxiliary heating heating resistor for assisting heating are disposed for each nozzle.

  That is, the technical contents of the present invention can solve the above-described problems by including the following configuration.

  (1) On a substrate, an insulating film made of an insulator, a plurality of foaming resistor arrays for generating heat necessary for foaming the ink, and a plurality of assisting heaters for heating the foaming resistor A substrate for an inkjet discharge head provided with a heating resistor array for auxiliary heating and a plurality of ink path arrays communicating with an ejection port for discharging ink, the heating resistor for foaming and the insulating layer interposed between A heating resistor for auxiliary heating is provided directly below, and a wiring electrically connected to the heating resistor is provided directly below the insulating layer, and a heating resistor for foaming is provided on the vertical line of the substrate. The region is located outside the wall portion of the ink path in the column direction, and the region of the auxiliary heating heating resistor overlaps the wall portion of the ink path in the column direction.

  (2) On the substrate, an insulating film made of an insulator, a plurality of foaming heating resistors that generate heat necessary for foaming the ink, and a plurality of assistants that assist the heating of the foaming heating resistors A substrate for an inkjet discharge head provided with a heating heating resistor and a plurality of ink passages communicating with an ejection port for discharging ink, and assists directly under the heating heating resistor and an insulating layer. Heating resistor for heating, and wiring to be electrically connected to the heating resistor directly below the insulating layer, and one electrode connected to the heating resistor for foaming and auxiliary One electrode connected to the heating exothermic resistor and the wiring electrode directly below the electrode are connected through the same through-hole.

  According to the present invention, it is possible to provide an ink jet recording head that maximizes the performance of a heating resistor and has a high density, and the head substrate.

  An ink jet recording head substrate according to the present invention includes an insulating film made of an insulator on the substrate, a plurality of foaming heating resistor arrays that generate heat necessary for foaming the ink, and the foaming heating resistor. A plurality of auxiliary heating heating resistor rows for assisting heating and a plurality of ink path rows communicating with ejection openings for discharging ink are provided, and the region of the foaming heating resistor on the vertical line of the substrate is the row. It is located outside the wall of the ink path in the direction, and the region of the heating resistor for auxiliary heating overlaps the wall of the ink path in the column direction. By driving the heating resistor for heating, a region that is slightly larger than the region for the heating resistor for foaming is heated, and when the heating resistor for foaming is heated, lateral heat escape is suppressed, Effective foaming over the entire resistor area Make.

  The inkjet recording head substrate of the present invention includes an insulating film made of an insulator on the substrate, a plurality of foaming heating resistors that generate heat necessary for foaming the ink, and the foaming heating resistors. A substrate for an ink jet discharge head provided with a plurality of heating resistors for auxiliary heating for assisting heating and a plurality of ink paths communicating with discharge ports for discharging ink, the heating resistor for foaming, and an insulating layer A heating heating resistor for auxiliary heating directly under it, and a wiring to be electrically connected to the heating resistor directly under the insulating layer, and one side connected to the heating heating resistor for foaming And the heating electrode for foaming at the same pitch as the nozzle pitch by connecting one electrode connected to the heating resistor for auxiliary heating, and the wiring electrode directly thereunder through the same through-hole. ,auxiliary It realized placing a thermal heating resistor.

  As described above, according to the present invention, it is possible to provide an ink jet recording head that maximizes the performance of the heating resistor and has a high density, and the head substrate.

  Hereinafter, the present invention will be described in more detail with reference to examples.

  FIG. 1 is a schematic top view showing the main part of the substrate for an ink jet recording head of the present invention. FIG. 2 is a schematic side cross-sectional view taken along the one-dot chain line X1-X2 in FIG.

  As shown in FIGS. 1 and 2, an insulating film is formed on the ink jet substrate, wiring to be connected to the heating resistor is formed, then the insulating film is formed, and then the auxiliary heating heating resistor) is disposed. Next, an insulating film is formed, and then a foaming heating resistor is formed, and the wiring, the auxiliary heating resistor, and the foaming heating resistor are connected through the through holes. A protective film is formed thereon, and then anti-cavitation is formed. Thereafter, a nozzle wall and a flow dew path member are formed on the ink jet substrate, and the head shown in FIG. 5 is completed.

  A manufacturing method of the ink jet recording head substrate having this structure will be described with reference to FIG. 4, and a manufacturing method of the ink jet recording head will be described with reference to FIG.

  First, the Si crystal orientation is <1.0.0. > A Si substrate 1 having a surface is prepared. This Si substrate may be one in which a semiconductor element for driving a heater is previously formed, and an SiO insulating layer 70 is formed on the uppermost layer. An AL of about 500 nm is formed on the substrate by sputtering, a resist is formed into a predetermined shape by photolithography, and this is used as an etching mask, and etched into a predetermined shape by a reactive ion etching method in which BCl3 and Cl2 gas are mixed. Thereafter, the resist, etching residue, and the like are removed by plasma ashing using O 2 and wet stripping liquid to form a predetermined shape as a wiring.

  For connection with a semiconductor, a resist is formed in a predetermined shape on an insulating layer of SiO by photolithography in advance, and this is used as an etching mask, and etched into a predetermined shape by a reactive ion etching method using CF4. Thereafter, the resist and etching residue are removed by plasma ashing with O 2 and wet wiping solution to form a through hole, and connection is made by sputtering of AL.

  Subsequently, an insulating film SiO71 for protecting this wiring is formed to a thickness of about 800 nm by the CVD method. Subsequently, a resist is formed into a predetermined shape by the photolithography method, which is used as an etching mask, and a reactive film using CF4 is used. Etching into a predetermined shape by ion etching. Thereafter, the resist, etching residue, and the like are removed by plasma ashing using O 2 and wet stripping liquid, thereby forming a through hole.

  Subsequently, a TaSiN heating resistor 40 is formed as an auxiliary heating resistor to a thickness of about 40 nm by a sputtering method, and then a connection AL layer 25 is formed to a thickness of 500 nm, and this is used as an etching mask by a photolithography method. Etching into a predetermined shape by a reactive ion etching method in which a Cl2 gas is mixed. Thereafter, the resist and etching residue, etc. are removed by plasma ashing using O2 and a wet stripping solution, and again using the photolithographic method as an etching mask, and by using AL wet etching mixed with acetic acid and phosphoric acid, The auxiliary heating exothermic resistor section 60 is formed by removing the AL, and then removing the resist and etching residue by plasma ashing with O 2 and wet stripping solution.

  Next, an insulating film SiO72 is formed on the heating resistor and AL to a thickness of about 800 nm by the CVD method. Subsequently, a resist is formed into a predetermined shape by the photolithography method, and this is used as an etching mask. Etching into a predetermined shape by the active ion etching method. Thereafter, the resist, etching residue, and the like are removed by plasma ashing using O 2 and wet wiping solution to form a through hole.

  Subsequently, a TaSiN heat generating resistor 41 is formed as a foaming heat generating resistor to a thickness of about 40 nm by a sputtering method, and then a connection AL layer 26 is formed to a thickness of 500 nm, and this is used as an etching mask by a photolithography method. Etching into a predetermined shape by a reactive ion etching method in which a Cl2 gas is mixed. Thereafter, the resist and etching residue are removed by plasma ashing with O2 and wet ash solution, and again by using the photolithography method as an etching mask, and by AL wet etching in which acetic acid and phosphoric acid are mixed, the AL of the heating resistor portion for foaming is used. Then, the resist and the etching residue are removed by plasma ashing using O 2 and a wet brush solution, thereby forming the foaming heating resistor portion 65.

  Next, a protective film SiN30 is formed to a thickness of about 300 nm by the CVD method, and then a cavitation-resistant Ta50 film is formed to a thickness of about 200 nm by the sputtering method, and a CF4 gas is applied to the Ta film by the photolithography method. Reactive ion etching is used to obtain a predetermined shape, and then the resist and etching residue are removed by plasma ashing using O2 and a wet stripping solution. Subsequently, the resist is formed into a predetermined shape by photolithography, and then a reaction using CF4 is performed. The protective film is etched into a predetermined shape by reactive ion etching, and then the resist and etching residue are removed by plasma ashing using O 2 and wet wiping solution to form an electrode pad portion.

  The electrical functional part of the substrate is completed through the above steps.

  Next, a method for manufacturing the nozzle and the ink supply portion will be described. FIG. 5 is a schematic perspective view of the ink jet recording head after the manufacture is completed, and will be described below in order.

This ink jet recording head (liquid ejection head) has a Si substrate 1 on which ink ejection energy generating elements (liquid ejection energy generating elements) 2 are formed in two rows at a predetermined pitch. As will be described later, the Si substrate 1 has ink supply ports (liquid supply ports) 9 formed by anisotropic etching of Si using the SiO ₂ film 7 as a mask in two rows of the ink ejection energy generating elements 2. There is an opening in between. On the Si substrate 1, an ink ejection port (liquid ejection port) 5 opened above each ink ejection energy generating element 2 and an ink communicating from the ink supply port 9 to each ink ejection port 5 by an orifice plate material 4. A flow path (liquid flow path) is formed.

  In FIG. 5, for the sake of simplicity, the ink discharge energy generating element 2 and the ink discharge port 5 are described as being symmetrically arranged with the ink supply port 9 in between. The two rows of ink ejection energy generating elements 2 and the ink ejection ports 5 sandwiching the port 9 are arranged with a half-pitch shift.

  This ink jet recording head is arranged so that the surface on which the ink supply port 9 is formed faces the recording surface of the recording medium. The ink jet recording head applies an ink liquid from the ink discharge port 5 by applying a pressure generated by the ink discharge energy generating element 2 to the ink (liquid) filled in the ink flow path via the ink supply port 9. Recording is performed by ejecting the droplets 6 and attaching them to a recording medium.

  The ink jet recording head can be mounted on an apparatus such as a printer, a copying machine, a facsimile having a communication system, a word processor having a printer unit, or an industrial recording apparatus combined with various processing apparatuses. By using this ink jet recording head, recording can be performed on various recording media such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics. In the present invention, “recording” means not only giving an image having a meaning such as a character or a figure to a recording medium but also giving an image having no meaning such as a pattern. .

  In the present embodiment, as described above, the Si substrate 1 having the <100> Si crystal orientation on the surface on which the ink ejection energy generating element 2 is formed is used. The manufacturing method of the ink discharge part and the supply port will be described with reference to FIGS. First, the mold material 103 is formed on the surface of the Si substrate 1 on which the ink ejection energy generating element, that is, the heater 102 is formed. This mold material 3 is formed so as to be melted in a later step to form a portion provided with it as an ink flow path. In order to form an ink flow path having a desired height and a plane pattern, It is formed in a suitable height and plane pattern. Such a mold 103 can be formed as follows, for example.

  First, for example, a positive photoresist ODUR1010 (registered trademark) (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is used as a material of the mold material 103, and this is predetermined on the Si substrate 1 by dry film lamination, spin coating, or the like. Apply at a thickness of. Next, patterning is performed using a photolithographic technique in which exposure and development are performed using ultraviolet rays, deep UV light, or the like. Thereby, the mold material 3 having a desired thickness and a planar pattern is obtained.

  Next, an orifice plate material 104 is applied by spin coating or the like on the Si substrate 1 so as to cover the mold material 3 formed in the previous step, and is patterned into a predetermined shape by a photolithography technique. Then, an ink discharge port 105 is opened at a predetermined position on the ink discharge energy generating element 102 by photolithography. Further, a water-repellent layer 106 is formed on the surface of the orifice plate material 104 where the ink discharge port 105 opens by dry film lamination or the like.

  As the material of the orifice plate material 104, a photosensitive epoxy resin, a photosensitive acrylic resin, or the like can be used. The orifice plate material 104 constitutes a nozzle wall between the ink flow path and the foaming heating resistor, and is always in contact with ink when the ink jet recording head is used. In particular, a cationically polymerizable compound by photoreaction is suitable. In addition, as the material of the orifice plate material 104, durability and the like are greatly affected by the type and characteristics of the ink used, and accordingly, an appropriate compound other than the above materials may be selected depending on the ink used.

Next, an SiO ₂ film patterning mask 108 which is a mask agent having alkali resistance is formed on the SiO ₂ film 107 on the back surface of the Si substrate 1. The SiO ₂ film patterning mask 108 is formed as follows, for example.

First, a mask agent to be the SiO ₂ film patterning mask 108 is applied to the entire back surface of the Si substrate 1 by spin coating or the like and thermally cured. Further, a positive resist is applied thereon by spin coating or the like and dried. Next, the positive resist is patterned using a photolithography technique, and the exposed portion of the mask agent that becomes the SiO ₂ film patterning mask 108 is removed by dry etching or the like using the positive resist as a mask. Finally, the positive resist is peeled off to obtain a SiO ₂ film patterning mask 108 having a predetermined pattern.

Then, using the SiO ₂ film patterning mask 108 as a mask, the SiO ₂ film 107 is patterned by wet etching or the like to open an etching start opening 109 that exposes the back surface of the Si substrate 1.

Next, the ink supply port 110 that is a through-hole penetrating the Si substrate 1 is opened by anisotropic etching using the SiO ₂ film 107 as a mask. At this time, a protective material 111 made of resin is applied by spin coating or the like so as to prevent the etching solution from touching the surface on which the functional element of the ink jet recording head is formed or the side surface of the Si substrate 1. Form it. As the material of the protective material 111, a material having sufficient resistance to a strong alkaline solution used when performing anisotropic etching is used. By covering the orifice plate material 4 with such a protective material 111 as well, it is possible to prevent the deterioration of the water repellent layer described above.

  As an etchant used for anisotropic etching, for example, a strong alkali solution such as a TMAH (tetramethylammonium hydroxide) solution is used. Then, for example, a TMAH 22 wt% solution is applied to the Si substrate 1 from the etching start opening 109 at a temperature of 80 ° C. for a predetermined time (ten hours or more), thereby opening the through hole.

Finally, the SiO ₂ film patterning mask 108 and the protective material 111 are removed. Further, the mold material 103 is dissolved and removed by elution from the ink discharge port 5 and the ink supply port 9 or 110 and dried. The elution of the mold material 103 can be carried out by performing development after exposing the entire surface with Deep UV light, and if necessary, the mold material 103 can be substantially completely removed by ultrasonic immersion during development. Can do.

  Thus, the main manufacturing process of the ink jet recording head is completed. The chip formed in this manner is provided with a connecting portion for driving the ejection energy generating element 102, a chip tank for supplying ink, and the like as necessary.

  The substrate shown in FIG. 4a thus prepared was compared with the foamed region of the conventional structure shown in FIG. 3a. As a result, the foamed region in FIG. In Fig. 4b, the foaming region was expanded by driving the auxiliary heating heating resistor.

Typical top view which shows the principal part of the board | substrate for inkjet recording heads of this invention. Schematic side cross-sectional view cut along the alternate long and short dash line of X1-X2 in FIG. The figure which shows the board | substrate of the conventional inkjet recording head. The figure which shows the foaming area | region of the board | substrate of the conventional inkjet recording head The figure which shows the board | substrate of the inkjet recording head of this invention The figure which shows the foaming area | region of the board | substrate of the inkjet recording head of this invention Schematic perspective view of the inkjet recording head of the present invention Diagram showing manufacturing process of inkjet recording head

Explanation of symbols

1 Si substrate 2 Ink discharge energy generating element (that is, heater or heating resistor)
4 Orifice plate material 5 Ink discharge port 6 Ink droplet 9 Ink supply port 20 Al wiring and Al wiring layer 25 AL layer for connection 26 AL layer for connection 30 Protective film SiN
40 TaSiN Heating Resistor 41 TaSiN Heating Resistor 50 Ta Cavitation Resistant Film 60 Heating Resistor Part 65 for Auxiliary Heating Heating Resistor Part 70 for Foaming SiO Insulating Layer 71 SiO Insulating Layer 72 SiO Insulating Layer 80 Through Hole 85 Foaming Area 102 Ink Discharge energy generating element 103 Mold material 104 Orifice plate material 105 Ink discharge port 106 Water repellent layer 107 SiO2 film 108 SiO2 film patterning mask 109 Etching start opening 110 Ink supply port 111 Protective material

Claims (3)

On the substrate, an insulating film made of an insulator, a plurality of foaming resistor arrays that generate heat necessary for foaming the ink, and a plurality of auxiliary heating aids that assist the heating of the foaming resistor A substrate for an inkjet discharge head provided with a plurality of ink path rows communicating with a heating resistor row and a discharge port for discharging ink,
A heating resistor for foaming, a heating resistor for auxiliary heating directly under the insulating layer, and a wiring for electrically connecting to the heating resistor directly under the insulating layer are provided. In addition, on the vertical line of the substrate, the region of the foaming heating resistor is positioned outside the wall portion of the ink path in the column direction, and the region of the auxiliary heating heating resistor is the wall portion of the ink path in the column direction. A substrate for an inkjet discharge head, wherein the substrate is overlapped with the substrate. An insulating film made of an insulator on the substrate, a plurality of foaming heating resistors that generate heat necessary for foaming the ink, and a plurality of auxiliary heating heat generations that assist the heating of the foaming heating resistor A substrate for an inkjet discharge head provided with a resistor and a plurality of ink paths communicating with an ejection port for ejecting ink,
A heating resistor for foaming, a heating resistor for auxiliary heating directly under the insulating layer, and a wiring for electrically connecting to the heating resistor directly under the insulating layer are provided. And one of the electrodes connected to the heating resistor for foaming, the one electrode connected to the heating resistor for auxiliary heating, and the wiring electrode directly below it are connected via the same through-hole. An inkjet discharge head substrate.   2. The substrate for an ink jet discharge head according to claim 1, wherein a region of the auxiliary heating heating resistor is wider than a region of the foaming heating resistor in the column direction.