JP2012143998A - Inkjet head and inkjet recording apparatus - Google Patents

Abstract

The present invention provides an ink jet head that can be reduced in size even when the degree of integration is increased, and an ink jet recording apparatus having the ink jet head, while preventing damage during flip chip mounting or wire bonding mounting. The purpose is to do.
A plurality of liquid chambers are formed in which a space between a nozzle substrate on which a plurality of nozzles is formed and a vibration plate arranged on the nozzle substrate is separated by a partition wall. In the inkjet head 100, a piezoelectric element 120 in which a common electrode 121, a piezoelectric body 122, and an individual electrode 123 are sequentially stacked is formed in a space separated by a partition 112b of a diaphragm 112a. A wiring 140 is drawn from the individual electrode 123, and an electrode pad 141 that electrically connects the wiring 140 and the driving IC 150 is formed on the wiring 140. The electrode pad 141 extends on the partition 112b. .
[Selection] Figure 1

Description

  The present invention relates to an inkjet head and an inkjet recording apparatus.

  In recent years, inkjet printers have been widely used, but cost reduction and size reduction are required.

  As an inkjet head manufacturing method, a MEMS (micro electro mechanical systems) technique, which is a microfabrication technique using a semiconductor process, is adopted. For example, components such as a liquid chamber, a diaphragm, and a piezoelectric element can be formed on a silicon substrate by using a processing method such as etching, sputtering, or spin coating. By miniaturizing these components or devising the arrangement of the components, the inkjet head can be miniaturized. As a result, many inkjet heads can be manufactured from one silicon substrate, and the cost can be reduced.

  Patent Document 1 discloses a flow path forming substrate in which a pressure generation chamber communicating with a nozzle opening is defined by a plurality of partition walls, a lower electrode provided on one surface side of the flow path forming substrate via a diaphragm, and a piezoelectric element. An ink jet recording head comprising a body layer and a piezoelectric element comprising an upper electrode is disclosed. At this time, a drive circuit for driving the piezoelectric element is provided on the piezoelectric element side of the flow path forming substrate, and the piezoelectric element and the drive circuit are connected via a drive wiring made of a bonding wire. Is provided in a region facing the partition wall.

  However, since the connecting portion between the piezoelectric element and the drive wiring is provided in a region facing the partition wall, there is a problem that if the degree of integration is increased, the inkjet head cannot be reduced in size. On the other hand, if the connection part between the piezoelectric element and the drive wiring is provided in a region facing the ink flow path formed on the flow path forming substrate, the flow path forming substrate is damaged by applying a load when bonding the bonding wire. There is a problem of doing.

  SUMMARY OF THE INVENTION In view of the above-described problems of the prior art, the present invention provides an ink jet head that can prevent downsizing during flip chip mounting or wire bonding mounting, and can be miniaturized even if the degree of integration is increased. It is an object of the present invention to provide an inkjet recording apparatus having the above.

  According to the first aspect of the present invention, a plurality of liquid chambers are formed in which a space between a nozzle substrate on which a plurality of nozzles are formed and a diaphragm arranged on the nozzle substrate is separated by a partition wall. In the inkjet head, a piezoelectric element in which a common electrode, a piezoelectric body, and an individual electrode are sequentially laminated is formed in a space separated by the partition wall of the diaphragm, and wiring is performed from the individual electrode. And an electrode pad for electrically connecting the wiring and the drive circuit is formed on the wiring, and the electrode pad extends on the partition wall.

  According to a second aspect of the present invention, in the ink jet head according to the first aspect, the electrode pad extends on the partition wall on both sides in a direction perpendicular to the longitudinal direction of the liquid chamber. Features.

  According to a third aspect of the present invention, in the ink jet head according to the first or second aspect, the electrode pad is connected to the drive circuit by flip chip mounting or wire bonding mounting.

  According to a fourth aspect of the present invention, in the inkjet head according to any one of the first to third aspects, the electrode pad is connected to the drive circuit by wire bonding mounting, and In addition, a second substrate on which a flow path for supplying a liquid to the liquid chamber is formed and a third substrate on which a second liquid chamber connected to the flow path is formed are sequentially provided. A member on which the drive circuit is formed is provided on the third substrate.

  According to a fifth aspect of the present invention, in the inkjet head according to any one of the first to fourth aspects, the liquid chamber has a width of an end portion on the side where the electrode pad is formed, the electrode pad. It is characterized in that it is smaller than the width of the region where no is formed.

  A sixth aspect of the present invention is the inkjet head according to any one of the first to fifth aspects, wherein the direction between the common electrode and the electrode pad is substantially perpendicular to the longitudinal direction of the liquid chamber. Further, a second wiring is formed in contact with the common electrode.

  According to a seventh aspect of the present invention, in the ink jet recording apparatus, the ink jet head according to any one of the first to sixth aspects is provided.

  According to the present invention, there is provided an ink jet head capable of suppressing breakage during flip chip mounting or wire bonding mounting and miniaturizing even if the degree of integration is increased, and an ink jet recording apparatus having the ink jet head. be able to.

1 is a partial view showing a first embodiment of an inkjet head of the present invention. FIG. 8 is a top view showing a modification of the arrangement of the electrode pads in FIG. 1. FIG. 6 is a top view showing a modification of the shape of the liquid chamber in FIG. 1. It is a fragmentary sectional view which shows the modification of the inkjet head of FIG. It is a fragmentary sectional view which shows 2nd embodiment of the inkjet head of this invention. It is sectional drawing which shows the modification of the inkjet head of FIG.

  Next, the form for implementing this invention is demonstrated with drawing.

  FIG. 1 shows a first embodiment of an ink jet head of the present invention. 1A and 1B are a cross-sectional view and a top view, respectively. In FIG. 1B, for the sake of simplification, the insulating layer 130, the driving IC 150, the aluminum pad 151, the gold plating 152, and the solder are shown. The description of the bump 160 is omitted.

  In the inkjet head 100, a plurality of liquid chambers 110 are formed in two rows in a staggered manner. The plurality of liquid chambers 110 includes a nozzle substrate 111 in which a plurality of nozzles 111a are formed, and a liquid chamber substrate 112 having a diaphragm 112a and a partition 112b disposed on the nozzle substrate 111 using an adhesive or the like. It is joined. That is, in the plurality of liquid chambers 110, the space between the nozzle substrate 111 and the vibration plate 112a is separated by the partition 112b.

  Although it does not specifically limit as a material which comprises the nozzle substrate 111, Stainless steel, a polyimide, etc. are mentioned.

The liquid chamber substrate 112 is provided with a supply port through which a diaphragm 112a (etch stop layer) having a laminated structure including a SiO ₂ film, a Si ₃ N ₄ film, etc. supplies liquid to the liquid chamber 110 described later by sputtering or the like. It can be formed by etching a silicon substrate formed in a region excluding the region.

  The liquid chamber substrate 112 preferably has a thickness of 100 μm or less.

  The thickness of the diaphragm 112 a is appropriately selected according to the width of the liquid chamber 110. For example, when the width of the liquid chamber 110 is about 60 μm, the thickness of the diaphragm 112a is about 1 to 3 μm.

  In addition, a common electrode 121 is formed on the vibration plate 112a, and the piezoelectric body 122 and the individual electrode 123 are sequentially stacked in a space separated by the partition 112b of the common electrode 121. That is, the piezoelectric element 120 is formed in a space separated by the partition 112b of the diaphragm 112a.

  A method of forming the common electrode 121 is not particularly limited, and a method of forming a film of platinum and titanium by sputtering or the like can be given.

  A method of forming the piezoelectric body 122 is not particularly limited, and examples thereof include a method of forming a film by sputtering, a sol-gel method or the like and then patterning by etching or the like.

  A method for forming the individual electrode 123 is not particularly limited, and examples thereof include a method of forming a platinum film by sputtering or the like and then patterning by etching or the like.

  An insulating layer 130 is formed on the vibration plate 112a on which the piezoelectric element 120 is formed. Further, the wiring 140 is drawn from the individual electrode 123 through the contact hole 131 in the space separated by the partition 112 b of the insulating layer 130. In addition, by flip chip mounting, electrode pads 141 that electrically connect each wiring 140 and driving IC 150 are formed on each wiring 140 so as to form a two-row staggered pattern. At this time, the electrode pad 141 extends on the partition walls 112 b on both sides in the direction perpendicular to the longitudinal direction of the liquid chamber 110.

  Thus, since the electrode pad 141 is formed in the space separated by the partition 112b, the inkjet head 100 can be downsized even if the degree of integration is increased. In addition, since the electrode pads 141 extend on the partition walls 112b on both sides in the direction perpendicular to the longitudinal direction of the liquid chamber 110, damage during flip chip mounting can be suppressed.

  As shown in FIG. 2A, the electrode pad 141 is formed on a space separated by the partition 112b, and is on one side of the partition parallel to the longitudinal direction of the liquid chamber 110. It may extend on 112b. At this time, the electrode pads 141 may be further formed on the partition walls 112b on both sides in the direction perpendicular to the longitudinal direction of the liquid chamber 110, as shown in FIG.

  In addition, as shown in FIG. 2C, the electrode pad 141 is formed in a space separated by the partition 112b and is on one side of the partition perpendicular to the longitudinal direction of the liquid chamber 110. It may extend on 112b. At this time, the electrode pad 141 may be further formed on the partition wall 112b on one side in a direction parallel to the longitudinal direction of the liquid chamber 110, as shown in FIG.

  Although it does not specifically limit as the wiring 140, Aluminum wiring etc. are mentioned.

  The electrode pad 141 is not particularly limited, and examples thereof include nickel plating and gold plating.

  The electrode pad 141 preferably has a thickness of 10 μm or more. When the thickness of the electrode pad 141 is less than 10 μm, the deflection due to the load at the time of flip chip mounting (or at the time of wire bonding mounting) increases, and the bonding reliability may decrease.

  On the mounting surface side of the driving IC 150, an aluminum pad 151 and a gold plating 152 are sequentially stacked at a position corresponding to the electrode pad 141, and a solder bump 160 is formed between the electrode pad 141 and the gold plating 152. The driving IC 150 is positioned with respect to the electrode pad 141 by a die bonder or the like, and can be joined by heating and press-contacting.

  A gold bump may be used instead of the solder bump.

  In the liquid chamber 110, the width of the end portion on the side where the electrode pad 141 is formed is preferably smaller than the width of the region where the electrode pad 141 is not formed. Thereby, the damage at the time of flip chip mounting can be further suppressed.

  Specifically, as shown in FIG. 3A, the liquid chamber 110 may have an R shape when the end portion on the side where the electrode pad 141 is formed is viewed from the top, as shown in FIG. As shown in FIG. 4B, when the end portion on the side where the electrode pad 141 is formed is viewed from the top, it may be tapered.

  In addition, the shape of the end of the liquid chamber 110 on the side where the electrode pad 141 is formed is not limited to the R shape and the tapered shape.

  FIG. 4 shows a modification of the inkjet head 100. The inkjet head 100A is an inkjet head except that a wiring 170 exposed on the surface through a contact hole 132 is formed in a region surrounded by the electrode pad 141 between the common electrode 121 and the insulating layer 130. 100. Thereby, the damage at the time of flip chip mounting can be further suppressed. Further, as the distance in the direction substantially perpendicular to the longitudinal direction of the liquid chamber 110 from the terminal for inputting a voltage to the common electrode 121 is increased, the resistance value can be suppressed from gradually increasing.

  FIG. 5 shows a second embodiment of the inkjet head of the present invention. The ink jet head 200 is bonded onto the vibration plate 112a, and a liquid supply substrate 210 in which a flow path (not shown) for supplying a liquid to each liquid chamber 110 and an opening 212 through which the bonding wire 220 passes are formed. The configuration is the same as that of the inkjet head 100 except that the driving IC 150 is installed on the top and wire bonding is mounted. In the ink jet head 200, the electrode pad 141 is connected to the driving IC 150 by a bonding wire 220. For this reason, the inkjet head 200 can be reduced in size without depending on the size of the drive IC 150. Moreover, the damage at the time of wire bonding mounting can be suppressed.

  The material constituting the liquid supply substrate 210 is not particularly limited, and examples thereof include glass and silicon.

  FIG. 6 shows a modification of the inkjet head 200. The inkjet head 200 </ b> A has the same configuration as the inkjet head 200 except that the drive IC 150 is bonded together with the FPC 240 on the frame substrate 230 bonded to the liquid supply substrate 210. For this reason, the width of the inkjet head 200A can be reduced. Further, the liquid supply substrate 210 is formed with a flow path 211 for supplying a liquid to each liquid chamber 110 and an opening 212 through which the bonding wire 220 passes. Further, the frame substrate 230 is formed with an opening 232 through which the common liquid chamber 231 connected to the plurality of flow paths 211 and the bonding wire 220 pass. At this time, since the common liquid chamber 231 is formed on a region including a part of the liquid chamber 110, the inkjet head 200A can be further downsized.

  The liquid chamber substrate 112 is provided with a supply port 112 c that supplies liquid from the flow path 211 to the liquid chamber 110 and a resistance portion 112 d that becomes resistance when supplying liquid to the liquid chamber 110. The resistance portion 112d functions as a resistance by making the width smaller than that of the liquid chamber 110.

  A method for forming the supply port 112c and the resistance portion 112d of the liquid chamber substrate 112 is not particularly limited, and examples thereof include etching.

  A method of forming the flow path 211 and the opening 212 of the liquid supply substrate 210 is not particularly limited, and examples thereof include etching.

  A method of forming the common liquid chamber 231 and the opening 232 of the frame substrate 230 is not particularly limited, and examples thereof include etching.

  In the inkjet head 200A, the liquid is supplied from the common liquid chamber 231 to the liquid chamber 110 through the flow path 211 and the supply port 112d.

  In the FPC 240, electrodes are patterned at positions corresponding to the terminals of the driving IC 150, and signals and power can be input by wiring. When a voltage is applied to the piezoelectric element 120 as an actuator by a signal and electric power input to the drive IC 150, the piezoelectric element 120 pressurizes the liquid chamber 110, and the liquid is discharged from the nozzle 111a.

  A damper film 250 is bonded on the frame substrate 230 in order to close the common liquid chamber 231. The damper film 250 has a resin film 252 bonded to a reinforcing plate 251 in which a notch 251a is formed.

  A top plate 260 is joined to the reinforcing plate 251 so as to cover the drive IC 150, and a sealing material 270 is injected.

  The ink jet recording apparatus of the present invention is not particularly limited as long as it has the ink jet head of the present invention.

100, 100A Inkjet head 110, 110A, 110B Liquid chamber 111 Nozzle substrate 111a Nozzle 112 Liquid chamber substrate 112a Diaphragm 112b Partition 112c Supply port 120 Piezoelectric element 121 Common electrode 122 Piezoelectric element 123 Individual electrode 130 Insulating layer 131, 132 Contact hole 140 Wiring 141 Electrode pad 150 Drive IC
151 Aluminum pad 152 Gold plating 160 Solder bump 170 Wiring 200, 200A Inkjet head 210 Liquid supply substrate 211 Flow path 220 Bonding wire 230 Frame substrate 231 Common liquid chamber

JP 2001-270125 A

Claims (7)

An ink jet head in which a plurality of liquid chambers are formed in which a space between a nozzle substrate on which a plurality of nozzles are formed and a diaphragm arranged on the nozzle substrate is separated by a partition,
A piezoelectric element in which a common electrode, a piezoelectric body, and an individual electrode are sequentially stacked is formed on a space separated by the partition of the diaphragm, and wiring is drawn from the individual electrode.
An electrode pad for electrically connecting the wiring and the drive circuit is formed on the wiring,
The ink jet head according to claim 1, wherein the electrode pad extends on the partition wall.   The inkjet head according to claim 1, wherein the electrode pad extends on the partition on both sides in a direction perpendicular to the longitudinal direction of the liquid chamber.   The inkjet head according to claim 1, wherein the electrode pad is connected to the drive circuit by flip chip mounting or wire bonding mounting. The electrode pad is connected to the drive circuit by wire bonding mounting,
A second substrate on which a flow path for supplying a liquid to the liquid chamber is formed and a third substrate on which a second liquid chamber connected to the flow path is formed on the diaphragm are sequentially formed. Provided,
The inkjet head according to claim 1, wherein a member on which the drive circuit is formed is provided on the third substrate.   5. The liquid chamber according to claim 1, wherein a width of an end portion on the side where the electrode pad is formed is smaller than a width of a region where the electrode pad is not formed. The inkjet head described in 1.   The second wiring is formed between the common electrode and the electrode pad so as to be in contact with the common electrode in a direction substantially perpendicular to a longitudinal direction of the liquid chamber. The inkjet head according to any one of 5.   An ink jet recording apparatus comprising the ink jet head according to claim 1.

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