JP2011213049A - Liquid discharge head and driving method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that there is a possibility that, if drive of a liquid discharge head is continued with a potential difference caused between a conducting layer covered with a resin channel component member having a wall surface defining the surface of a channel and ink in the channel will cause the material of the conducting layer to elute and show a migration phenomenon.SOLUTION: The liquid discharge head driving method is designed to drive a liquid discharge head 700 made up of a liquid discharge head board having a pair of first conducting layers supplying potential to drive a heater 704 and a second conducting layer to be connected to one of the pair of the first conducting layers, and a channel component member 108 having a discharge opening 703 and a portion 702a to be a wall surface defining the surface of the channel and provided so as to cover the second conducting layer and made of a resin so as to make the potential of the second conducting layer to be almost equal to the potential of a liquid in the channel.

Description

  The present invention relates to a liquid discharge head used for performing a recording operation by discharging a liquid, and a driving method thereof.

  In recent years, a plurality of energies used to drive a liquid discharge head used in a liquid discharge apparatus typified by an ink jet recording apparatus at a high frequency from the viewpoint of high-speed recording and high image quality, or to discharge liquid There is a need to drive the generating elements simultaneously.

  However, in a liquid discharge head in which a plurality of energy generating elements are connected to one wiring, when the plurality of energy generating elements are driven simultaneously, the energy for discharging generated by each energy generating element due to the influence of a voltage drop The amount will vary. This may make it difficult to keep the liquid discharge amount uniform. Therefore, it has been studied to reduce the influence of the voltage drop by lowering the resistance of the wiring.

  Patent Document 1 discloses a configuration in which a resistance is lowered by stacking a plurality of conductive layers vertically on an insulating layer with respect to a surface provided with an energy generating element. A cross-sectional view of the liquid discharge head disclosed in Patent Document 1 is shown in FIG. A heating resistance layer 1030, a pair of first conductive layers 1040, and an insulating layer 1050 are stacked on the substrate 1000, and energy is generated in a portion located between the pair of first conductive layers 1040. Used as the element 1060. One of the pair of first conductive layers 1040 1040 a is provided so as to be electrically connected to the second conductive layer 1100 provided on the insulating layer 1050. The second conductive layer 1100 is covered with a protective layer 1110 made of resin, and further has a discharge port 1130 thereon and a flow channel made of resin having a wall surface defining a surface of the flow channel 1140 communicating with the discharge port. A component 1120 is provided.

JP 2005-199701 A

  The liquid discharge head as in Patent Document 1 is driven by applying a potential difference (about 10 to 30 V) to the gap portion between the pair of first conductive layers 1040. For this reason, there is a possibility that the second conductive layer 1100 to which the high potential side is applied and the ink are positioned and provided with the protective layer 110 made of resin and the flow path component 1120 therebetween.

  In such a case, if a defective portion exists in the protective layer 1110 made of resin or the flow path component 1120, an electrochemical reaction may occur and the conductive material of the second conductive layer 1100 may be eluted into the ink.

  Further, even if there is no defect, ions may pass through the protective layer 1110 and the flow path component 1120 to cause a migration phenomenon, and the second conductive layer 1100 may be short-circuited with other wirings.

  According to the present invention, in a configuration in which a plurality of layers of conductive materials are stacked to reduce resistance, it is possible to reduce the elution of the material of the conductive layer covered with the resin material or the permeation of the resin material. An object of the present invention is to provide a highly reliable liquid discharge head.

  The liquid ejection head of the present invention is provided so as to cover a resistance layer made of a resistance material, a pair of first conductive layers provided in contact with the resistance layer, and the resistance layer and the pair of conductive layers. An insulating layer; and a second conductive layer provided so as to cover the insulating layer and electrically connected to one of the pair of first conductive layers through the insulating layer. A liquid discharge head substrate that uses a portion of the resistance layer between the conductive layers as a region for generating energy for discharging liquid from the discharge port; and a wall surface of a flow path that communicates with the discharge port. A liquid discharge head having a flow path constituent member made of a resin that forms the flow path by being provided in contact with the liquid discharge head substrate so as to cover the two conductive layers, the second conductive The layer and the liquid in the flow path have almost the same potential. Characterized in that it is driven.

  By providing as described above, a highly reliable liquid discharge head capable of reducing the elution of the material of the conductive layer covered with the resin material of the liquid discharge head or the permeation of the resin material is provided. can do.

1 is an example of a liquid discharge head and a liquid discharge apparatus according to the present invention. FIG. 3 is a cross-sectional view of the liquid ejection head according to the first embodiment. FIG. 2 is a schematic perspective view of a conductive layer used in the liquid discharge head of FIG. 1. FIG. 3 is a block diagram of a liquid ejection head according to the first embodiment. It is sectional drawing of the liquid discharge head which concerns on 2nd embodiment. It is an example of the layout of a 3rd conductive layer. It is sectional drawing of the conventional liquid discharge head.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Description of Liquid Discharge Head and Liquid Discharge Device]
FIG. 1A is a schematic perspective view of a liquid discharge head that can use the present invention, and FIG. 1B shows a liquid using a head unit equipped with such a liquid discharge head (inkjet recording head). It is a typical perspective view of a discharge device.

  A liquid discharge head 700 shown in FIG. 1A is provided with a liquid discharge head substrate 701 and a flow path constituting member 108. The liquid discharge head substrate 701 includes a plurality of energy generating elements 704 (hereinafter also referred to as heaters) that generate energy for discharging liquid onto the Si substrate. A flow path constituting member 108 having a discharge port 703 and a wall surface defining a surface of the flow path 702 communicating with the discharge port 703 is joined to the surface of the liquid discharge head substrate on which the heater is provided. The discharge port 703 and the portion that becomes the wall surface defining the surface of the flow path 702 are formed by a photolithography technique, and a plurality of heaters 704 are provided corresponding to each of the flow paths 702.

  The supply port 705 for supplying ink is formed in a rectangular shape so as to penetrate the front surface and the back surface of the liquid discharge head substrate 701 where the heater 704 is provided. A plurality of supply ports 705 can be provided in the liquid discharge head substrate 701, and a plurality of supply ports 705 can be provided in parallel so that long rectangular sides are adjacent to each other as shown in FIG. The plurality of heaters 704 are provided in one row (element row) on both sides of the supply port along the long side of each supply port 705. That is, the supply port 705 is disposed so as to be sandwiched between two element rows. On the opposite side of the row of heaters 704 to the supply port 705, switching elements made of nMOS or the like that perform ON / OFF control of the heaters 704 are connected to the respective heaters 704. In such a configuration, the liquid is conveyed from the supply port 705 to the discharge port 703 via the flow path 702.

  During the recording operation, the heater 704 selected by the switching element generates heat, and this thermal energy is added to the liquid in the flow path 702 to cause film boiling on the surface of the heater 704 to generate bubbles. A recording operation is performed by discharging a predetermined amount of liquid as droplets from the discharge port 703 provided facing the heater 704 by the generation pressure of the bubbles.

  At this time, electric power necessary for the heat generation of the heater 704 is supplied from the outside via a pad 706 that is an electrode pad provided at an end of the liquid discharge head substrate. FIG. 1B shows an example of a liquid ejection apparatus 800 that can use a head unit 801 equipped with such a liquid ejection head 700. A head unit 801 equipped with the liquid discharge head 700 is scanned on a recording sheet 802 used as a recording medium, whereby recording is performed on the recording sheet 802.

  Such a liquid discharge head 700 can be mounted on an apparatus such as a printer, a copier, 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 liquid discharge head, recording can be performed on various recording media such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, and ceramics.

  “Recording” used in this specification 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. I decided to.

  Furthermore, “liquid” is to be interpreted widely, and is applied to a recording medium to form an image, pattern, pattern, etc., process the recording medium, or process ink or recording medium. It shall refer to the liquid provided. Here, as the treatment of the ink or the recording medium, for example, the fixing property is improved by coagulation or insolubilization of the coloring material in the ink applied to the recording medium, the recording quality or coloring property is improved, and the image durability is improved. Say things like improvement.

[Layer Configuration of Liquid Discharge Head and Manufacturing Method]
An example of a layer configuration and a manufacturing method of the liquid discharge head according to the present invention will be described with reference to FIG. FIG. 2 schematically shows a cross-sectional view of the liquid discharge head.

  The substrate 100 made of silicon of the liquid discharge head 700 has a device including a switching element 101 for performing ON / OFF control of the heater 704 formed on the surface portion. Such a switching element 101 can be formed inside the surface of the substrate 100 using a semiconductor manufacturing process such as an ion implantation method.

  Here, an example in which an nMOS is used as the switching element 101 will be described. A polysilicon layer (not shown) that can be electrically connected to the switching element 101 and a third conductive layer 102 made of a conductive material such as aluminum are formed on the substrate 100. On the third conductive layer 102, a first insulating layer 110 made of an inorganic material that can ensure insulation with silicon as a main component, such as silicon oxide (SiO 2), is formed by a plasma CVD apparatus. A heating resistance layer 103 made of a material (resistance material) having a higher electrical resistance than aluminum such as TaSiN is provided on the first insulating layer 110, and a second layer made of a conductive material such as aluminum is further formed thereon. One conductive layer 104 is formed. The first insulating layer 110 is provided with a through hole 109a (through portion) and a through hole 109c that are used to electrically connect the third conductive layer 102 and the first conductive layer 104.

  Here, it is preferable that the film thickness of the first conductive layer 104 is 0.1 μm or more and 1 μm or less. The heat generating resistance layer 103 and the first conductive layer 104 can be formed using a dry etching method so as to form a wiring shape in a lump. Further, by removing a part of the first conductive layer 104 by using a wet etching method, a portion where the first conductive layer 104 is not provided can be provided on the heating resistance layer 103. A portion of the heating resistance layer 103 located between the pair of first conductive layers 104 is used as the heater 704.

  On top of this, a second insulating layer made of an inorganic material that can ensure insulation mainly composed of silicon, such as silicon nitride (SiN), as a passivation film for protecting a semiconductor surface having excellent barrier properties against impurities such as ions 105 is formed. Since such an inorganic material can be densely provided using a CVD method or the like, it is less likely to be damaged than a layer made of a material such as a resin, and ions are not easily transmitted. On the second insulating layer 105, a second conductive layer 106 is provided by providing a metal material made of gold, nickel, copper, silver, or the like using a plating method. The second insulating layer 105 is provided with a through hole 109 b for electrically connecting the first conductive layer 104 and the second conductive layer 106. By forming the second conductive layer 106 as a relatively thick film of about 2 μm or more and 15 μm or less, the resistance of the wiring for supplying a voltage for driving the heater can be lowered, and the influence of the voltage drop can be reduced. Can do.

  Thus, the first conductive layer 104 and the second conductive layer 106 are stacked on the substrate 100 (switching element 101) in a direction perpendicular to the surface of the substrate 100, thereby reducing the size of the liquid discharge head. However, it is possible to reduce the resistance of the wiring.

  Further, diffusion prevention as a barrier film or the like that prevents the metal material used for the second conductive layer 106 from diffusing into the first conductive layer 104 between the first conductive layer 104 (through portion) and the second conductive layer 106. A film (not shown) can also be provided. The second conductive layer 106 is provided on the second insulating layer 105 by providing a seed layer (not shown) for enabling growth of a metal material and performing plating using the seed layer as a nucleus. It has been. Note that an end portion of the second conductive layer 106 can also be used as the pad 706.

  As described above, the liquid discharge head substrate 701 is provided.

  On the upper side of the second conductive layer 106 of the liquid discharge head substrate 701, there are provided a discharge port 703 and a portion 702 a serving as a wall surface defining a surface of a flow path 702 that connects the discharge port 703 and the supply port 705. A flow path component 108 made of a curable resin such as an epoxy resin is provided. On the surface of the flow path component 108 in contact with the second conductive layer 106, a polyetheramide resin, which is a material that does not easily pass ions so as to cover the second conductive layer 106, in order to reliably prevent migration phenomenon and elution A protective layer 107 made of the above resin can also be provided. By providing the second conductive layer 106 with a material made of a resin that does not easily transmit ions in this way, migration phenomenon and elution can be reliably prevented. In addition, since the polyetheramide resin is a resin having adhesiveness with the second conductive layer 106 and the flow path component member 108, the protective layer 107 is provided using this material, so that the flow path component member 108 and the liquid can be liquidated. Adhesion with the discharge head substrate can be ensured.

  After the protective layer 107 is provided on the second conductive layer 106, the flow path component member 108 forms a mold material that becomes the flow path 702, applies a resin material that becomes the flow path component member 108, and then removes the mold material Then, it can be provided by forming a flow path. These processes can use photolithography or the like.

[About wiring]
A perspective view showing a state of the first conductive layer 104 is shown in FIG. From the first conductive layer 104, a VH wiring (second wiring) for commonly supplying a power supply potential to each of the plurality of heaters 704, and a part of the GNDH wiring (first wiring) connected to each heater 704 A GNDH wiring portion 104d is provided. The VH wiring further includes a common wiring portion 104a that connects the pad 706 and the heater 704 in common, a divided wiring portion 104b that branches from the common wiring portion 104a, and an individual wiring portion that connects from the divided wiring portion 104b to each heater 704. 104c.

  The plurality of heaters 704 are divided into a plurality of groups, and the divided wiring portions 104b are provided by the number of groups (M) so as to be connected to the plurality (N) of heaters 704 belonging to this one group. It is time-division driven. (In other words, the number of heaters 704 is N × M.) The heaters 704 belonging to such a group are controlled not to be driven at the same time (time-division driving). For example, in the case of a liquid discharge head substrate having 64 heaters 704, these heaters 704 are divided into 8 groups every 8 heaters, and the 8 heaters in the group are sequentially driven at intervals of 20 μs. Thereby, the peak current flowing through the divided wiring portion 104b can be reduced, and the influence of the voltage drop can be reduced.

  The GNDH wiring portion 104 d is connected to the drain electrode made of the third conductive layer 102 of the switching element 101 through a through hole 109 c provided in the first insulating layer 110. A polysilicon layer (not shown) and a third conductive layer 102 are connected to the switching element 101. The polysilicon layer is used as a gate electrode, and the third conductive layer 102 is used as a source electrode and a drain electrode. Used. The drain electrode is connected to a GNDH wiring portion 104d made of the first conductive layer through a through hole 109c provided in the first insulating layer 110. Note that the electrode of the polysilicon layer or the third conductive layer 102 can also be used as an electrode of the selection circuit 201 (AND circuit or the like) that outputs a signal to the switching element 101.

  The source electrode of the switching element 101 is provided so as to be connected to the second conductive layer 106 through the through hole 109a and the through hole 109b. FIG. 3B schematically shows a perspective view of the second conductive layer 106. The second conductive layer 106 is connected to the pad 706 and used as a part of the GNDH wiring. The second conductive layer 106 is connected to the plurality of heaters 704 provided in the first conductive layer via the GNDH wiring portion 104 d and the switching element 101. Are electrically connected.

  When the heater 704 is driven, it is connected to a pad 706a connected to a VH wiring (second wiring) through which current flows toward the heater and a GNDH wiring (first wiring) having a potential at which current flows from the heater. A potential is applied to the pad 706b. Further, when the switching element 101 is turned on, a current of several tens to several hundreds of mA flows through the heater 704, and the heater 704 is driven to perform a recording operation.

  The heater 704 belonging to one time-division drive group connected to the divided wiring portion 104b provided in the first conductive layer 104 drives only one heater per unit time. Therefore, a change in current value, that is, a change in voltage drop that occurs when a plurality of heaters are simultaneously driven in the divided wiring portion 104b hardly occurs.

  On the other hand, since the GNDH wiring is commonly connected to the heaters 704 belonging to a plurality of time-division drive groups, the plurality of connected heaters 704 may be driven at the same time. In such a case, the current corresponding to the number of heaters that are driven simultaneously flows through the GNDH wiring. When a large amount of current flows in this way, a voltage drop occurs, so that driving energy fluctuates, and ink may not be ejected stably. Therefore, it is necessary to reduce the fluctuation of the voltage drop applied to the heater 704 by sufficiently reducing the resistance of the GNDH wiring.

  Therefore, it is necessary to reduce fluctuations in voltage drop by providing the second conductive layer 106 with a relatively thick GNDH wiring by plating.

  Further, since the VH wiring of the first conductive layer 104 is divided into groups of time-division driving, the resistance value may be constant even if the resistance value is high, and the first conductive layer 104 should be relatively thin. it can. Therefore, the film thickness of the second insulating layer 105 provided to protect the first conductive layer 104 from ink or the like can be made as thin as possible, and heat for foaming the ink can be efficiently transmitted. .

[Circuit]
FIG. 4 is an example of a circuit diagram showing the heater 704, the VH wiring (second wiring) and the GNDH wiring (first wiring) connected to the heater 704 in the present invention.

  A voltage of about 10 to 30 V is applied to the pad 706a from the liquid ejection apparatus main body. The pad 706a is connected to the VH wiring provided in the first conductive layer 104, and the individual wiring portion 104c provided by branching the VH wiring is connected to the heater 704.

  The pad 706b is connected to the second conductive layer 106 used as a part of the GNDH wiring to which the plurality of heaters 704 are connected in common. The gate electrode made of polysilicon of the switching element 101 is connected to a selection circuit 201 embedded in the substrate 100 and is used to input a signal to the switching element 101. The selection circuit 201 is further connected to another pad 706 for inputting a data signal, a block selection signal, and the like for selecting the heater 704 via a decoder (not shown), a latch circuit (not shown), and the like.

[Electrochemical reaction that occurs in wiring covered with resin]
The protective layer 107 made of resin covers the second conductive layer 106 to protect it from ink, and further ensures adhesion with the flow path component member 108. The protective layer 107 is provided on the surface on the side in contact with the second conductive layer 106 of the flow path component 108 made of a cured epoxy resin. Since the protective layer 107 and the flow path constituent member 108 made of such a resin are more easily permeable to ions than a dense silicon nitride film provided by a CVD method or the like used for a passivation film, the ions can be formed even if there is no defect. May be transmitted. Further, since it is a resin, it is likely to be broken and a pinhole or the like may be generated, and the second conductive layer 106 may come into contact with the ink.

  Even if the ions permeate or come into contact with the ink in this way, the second conductive layer 106 such as gold is more resistant to ink (resistance to water) than aluminum used in the second and third conductive layers. Corrosion does not occur because it is highly corrosive.

  However, when a large potential difference is generated between the second conductive layer 106 and the ink, an electrochemical reaction may occur. Therefore, a migration phenomenon occurs when ions permeate through a material made of resin, which may cause a short circuit with another conductive layer, resulting in poor conduction. Further, the second conductive layer 106 may elute in a state where it is in contact with the ink.

  The substrate 100 of the liquid discharge head substrate, which is a semiconductor substrate, is provided to have a GND potential (substrate potential) in order to stabilize the built-in switching element 101 characteristics. In general, since the insulating film is not provided in the supply port 705, when the liquid discharge head is filled with ink, the ink supplied through the supply port 705 provided through the substrate 100 is the GND potential. And the same potential. Further, the GND potential is connected to the liquid ejection device via the electrode pad 706. The GNDH potential is also connected to the liquid ejection device via the electrode pad 706, and the GND potential and the GNDH potential are provided to be substantially the same potential.

  If the voltage applied to the second conductive layer 106 is larger than the substrate potential (GND potential), the second conductive layer 106 is on the anode (anode) side and the ink is on the cathode (cathode) side. The second conductive layer 106 is eluted. In order to suppress such elution of the second conductive layer 106, (1) the potential of the second conductive layer 106 and the potential of the ink, that is, the potential of the second conductive layer 106 and the substrate potential are set to the same potential as much as possible. (2) It is necessary to provide the second conductive layer so as to have a negative (cathode) electrode lower than the substrate potential.

  Here, when the ON / OFF control of the heater 704 is performed by the switching element 101 as shown in the block diagram of FIG. 4, the switching element is OFF in the VH wiring used for applying a voltage to the heater 704. Even when the voltage is on, the voltage is being applied. Therefore, the potential difference (about 10 to 30 V) for driving the heater 704 is always applied to the VH wiring. Therefore, when the second conductive layer is used for the VH wiring, a migration phenomenon or elution is likely to occur. On the other hand, since the GNDH wiring is generally substantially the same GND potential as the substrate potential, there is no potential difference, and even a member made of resin can be eluted between the conductive layer used for the GNDH wiring and the ink. The nature is low.

  Accordingly, the VH wiring having a potential difference with respect to the ink potential is provided in the first conductive layer 104 which is covered with the second insulating layer 105 made of a dense inorganic material and is difficult to touch the ink. Further, the second conductive layer 106 can be provided so as not to elute by using the second conductive layer 106 that does not cause a potential difference with respect to the ink potential as a part of the GNDH wiring. Note that the second insulating layer 105 covering the first conductive layer 104 is preferably a passivation film having excellent barrier properties against impurities such as ions, and specifically, a silicon nitride (SiN) film is used. Can do.

  The second conductive layer 106 is preferably a material that can ensure adhesion to the resin material, and is preferably a material that has good ink resistance (corrosion resistance) and low resistance. Specifically, gold with excellent ink resistance, noble metal material such as low resistance copper or silver, nickel with good adhesion and resin resistance by forming a good oxide film, etc. One or more of the materials can be used. In order to further reduce the resistance, the second conductive layer 106 is preferably provided thicker than the first conductive layer 104, and can be easily thickened by using a plating method or the like.

  With such a configuration, a highly reliable liquid ejection head that can prevent migration and elution of the second conductive layer 106 without impairing the adhesion between the protective layer 107 and the second conductive layer 106 is provided. can do. As a more preferable example, the second conductive layer 106 can be provided by stacking gold and nickel. This is because when the surface of the second conductive layer 106 on the side in contact with the protective layer 107 is nickel, the adhesion between the protective layer 107 and the second conductive layer 106 can be further improved.

  Note that the wiring can be provided by stacking a plurality of conductive layers, whereby the resistance can be lowered without increasing the area of the substrate. Furthermore, by using the present invention, the area of the region where the conductive layer is provided can be made smaller than that of the conventional liquid discharge head, and chip shrink can be achieved that reduces the substrate size.

(First embodiment)
An example of an embodiment of the present invention will be described with reference to FIGS. On a substrate 100 on which a switching element 101 made of nMOS is provided, a polysilicon layer to be a gate electrode and a third conductive layer 102 to be a source electrode and a drain electrode are provided. The third conductive layer 102 is formed of an AL-Si alloy with a thickness of about 500 to 1000 nm. Further, a first insulating layer 110 made of silicon oxide having a thickness of about 1000 nm is formed on the third conductive layer 102. A thermal resistance layer made of TaSiN is formed thereon with a thickness of about 8 nm to 100 nm, and a first conductive layer 104 made of an AL-Cu alloy and having a thickness of about 100 to 1000 nm is provided thereon. The first conductive layer 104 is used for VH wiring as shown in FIG. On the first conductive layer 104, a second insulating layer 105 used as a passivation film is formed by stacking silicon oxide (SiN) with a thickness of about 200 nm to 400 nm. Further, TiW used as a diffusion preventing film is formed on the order of several hundred nanometers thereon, and the second conductive layer 106 having a thickness of 2 to 15 μm made of gold used as a part of the GNDH wiring is formed thereon. . Further, the substrate 100 is provided with an ink supply port 705 that penetrates the front surface on which the heater 704 is provided and the back surface on the opposite side.

  A protective layer 107 made of a polyether amide resin is provided on the second conductive layer 106 so as to cover the second conductive layer 106 and not come into contact with ink. Furthermore, a flow path constituting member 108 made of a cured product of an epoxy resin that forms a wall portion 702a that defines a surface of the flow path 702 that communicates the discharge port 703 and the supply port 705 is provided thereon. Ink is conveyed from the supply port 705 to the heater 704 via the flow path 702 and discharged from the discharge port 703.

  Further, the heating resistance layer 103 in the gap portion of the pair of first conductive layers 104 provided with a gap is used as the heater 704. The pair of first conductive layers 104 connected to the heater 704 is used as the individual wiring portion 104 c that is a part of the VH wiring and the GNDH wiring portion 104 d that is a part of the GNDH wiring through the switching element 101.

  A drain electrode of the switching element 101 made of the third conductive layer 102 is connected to the GNDH wiring portion 104 d through a through hole 109 c provided in the first insulating layer 105. A source electrode of the switching element 101 made of the third conductive layer 102 is connected to a part 104 e of the first conductive layer through a through hole 109 a provided in the first insulating layer 110. Further, a part 104e is connected to the second conductive layer 106 which becomes a part of the GNDH wiring through a through hole 109b provided in the second insulating layer 105.

  A part (part A) of these through holes 109b can be provided between the adjacent divided wiring portions 104b as shown in FIG. Further, another part (part B) of the through hole 109b is provided in an opening 119 provided in the common wiring portion 104b. By arranging in this way, the first conductive layer 104 and the second conductive layer 106 can be stacked on the region of the switching element 101, and the conductive layer of the liquid discharge head can be efficiently arranged. Can do.

  Note that the number of through holes 109b can be reduced by connecting the plurality of adjacent switching elements 101 in the third conductive layer 102 in common instead of providing the through holes 109b individually for each switching element 101. . Thereby, the area of the opening provided in the common wiring part 104b can be reduced, and the resistance of the common wiring part 104b of the VH wiring can be reduced.

  Further, by connecting the third conductive layer 102 connected to the plurality of switching elements 101 to the inspection terminal portion, even before the second conductive layer 106 is provided, the resistance value of the heater 704 and the switching element 101 Inspection such as operation confirmation can be performed.

  The switching element 101 is connected to the substrate 100 in order to operate stably, and is provided so that the substrate 100 has a GND potential. Since the supply port 705 is not provided with an insulating film, and ink is supplied from the supply port 705, the potential of the ink matches the GND potential. The second conductive layer 106 covered with the protective layer 107 is used as a conductive layer that applies a potential of the GNDH wiring to the heater 704. At this time, the GNDH wiring is substantially the same as the substrate potential and is substantially the same as the GND potential.

  As described above, the second conductive layer 106 covered with the protective layer 107 made of resin is used as a GNDH wiring having substantially the same potential as the GND potential. It can be driven so that the potential is substantially the same. Thereby, migration and elution of the second conductive layer 106 can be prevented, and a highly reliable liquid discharge head can be provided.

(Second embodiment)
In the first embodiment, a part of the through hole 109b is provided inside the opening provided in the common wiring portion 104b of the first conductive layer. This embodiment is different from the first embodiment in that a through hole 109b is provided without providing an opening in the common wiring portion 104b. Other configurations are the same as those in the first embodiment.

  FIG. 5A shows a cross-sectional view of the liquid ejection head of this embodiment, and FIG. 5B shows a schematic top view showing the first conductive layer. In the present embodiment, the through hole 109b is provided in a region between adjacent individual wiring portions 104c. At this time, one through hole 109b is provided so as to connect a part 104e of the first conductive layer connected to two adjacent heaters 704 and the second conductive layer 106. Further, the two GNDH wiring portions 104d connected to the two adjacent heaters 704 are provided in a region between the adjacent individual wiring portions 104c where the through hole 109b is not provided. At this point, the through hole 109c provided in the first insulating layer 110 is penetrated and electrically connected to the third conductive layer 102.

  By providing in this way, it is not necessary to provide an opening for providing the through hole 109b in the common wiring portion 104b made of the first conductive layer 104, and the resistance of the common wiring portion 104b can be further reduced.

(Modification)
An example of the layout of the second conductive layer 106 used as a part of the GNDH wiring that can be used in the first embodiment and the second embodiment is schematically shown in FIGS.

  FIG. 6A shows an example in which a row composed of a plurality of heaters 704 is divided into two, and a GNDH wiring is connected to the electrode pad 706 in common. FIG. 6B shows a configuration in which a plurality of rows of heaters 704 are commonly connected to one GNDH wiring, and electrode pads 706 provided at two different end portions are connected. FIG. 6C shows a configuration in which a plurality of rows of heaters 704 are commonly connected to one GNDH wiring, and are connected to one electrode pad 706 provided at an end portion. By reducing the number of electrode pads 706, the chip size can be reduced.

  Any of the layouts of the second conductive layer 106 can be appropriately used in the first embodiment and the second embodiment.

DESCRIPTION OF SYMBOLS 100 Substrate 101 Switching element 102 Third conductive layer 103 Heating resistance layer 104 First conductive layer 105 Second insulating layer 106 Second conductive layer 107 Protective layer 108 Flow path component 700 Liquid discharge head 701 Liquid discharge head substrate 702 Flow Path 703 Discharge port 704 Heater (energy generating element)
705 supply port

Claims (7)

A resistance layer made of a resistance material, a pair of first conductive layers provided in contact with the resistance layer, an insulating layer provided so as to cover the resistance layer and the pair of conductive layers, and the insulating layer A second conductive layer provided so as to cover and electrically connecting to one of the pair of first conductive layers through the insulating layer, and the resistance layer between the pair of first conductive layers A liquid discharge head substrate used as a region for generating energy for discharging the liquid from the discharge port,
A flow path configuration made of a resin having a wall surface of a flow path communicating with the discharge port and constituting the flow path by being provided in contact with the liquid discharge head substrate so as to cover the second conductive layer Members,
A liquid ejection head comprising:
The liquid discharge head, wherein the second conductive layer and the liquid in the flow path are driven so as to have substantially the same potential.   The protective layer made of a resin that does not easily transmit ions is provided between the flow path component member and the second conductive layer so as to cover the second conductive layer. The liquid discharge head according to 1.   The liquid discharge head according to claim 2, wherein the protective layer is made of a polyetheramide resin.   The liquid discharge head according to claim 1, wherein the flow path component member is made of a cured product of an epoxy resin.   The liquid discharge head according to claim 1, wherein the second conductive layer is made of gold.   The liquid discharge head substrate includes a substrate made of silicon having a switching element for performing ON / OFF control of the energy generating element on a surface portion, the substrate potential to which the switching element is connected, and the first 6. The liquid discharge head according to claim 1, wherein the potential of the two conductive layers is substantially equal. A resistance layer and a pair of first conductive layers provided in contact with the resistance layer with a gap on the surface, and energy for the gap portion to discharge liquid from the discharge port; A substrate used as an energy generating element to be generated; an insulating layer provided on the resistance layer and the pair of conductive layers; provided on the insulating layer; A second conductive layer electrically connected to one of the conductive layers, a liquid discharge head substrate,
A flow wall made of a resin that has a wall surface that defines a surface of a flow path that communicates with the discharge port and is provided on the liquid discharge head substrate so as to cover the second conductive layer. A road component;
A method of driving a liquid ejection head having
A driving method of a liquid discharge head, wherein driving is performed so that the potential of the second conductive layer and the potential of the liquid filled in the flow path become substantially the same potential.

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