JP2007190719A - Inkjet recording head and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording head which hardly decreases throughput due to an increase in flow resistance, while having high reliability by having a fine mesh filter prevented from being completely clogged. <P>SOLUTION: In this head of an engraved channel which is engraved from a supply port of a substrate to this side of each ejection pressure generating element, a filter layer, in which a plurality of holes or slits are opened, covers an engraved part. In a manufacturing method, the engraved part is formed in the substrate by introducing an isotropic etchant from the holes or the slits, which are opened in the filter layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording head that discharges a liquid such as ink as droplets and attaches it to a recording material such as paper to perform recording, and a manufacturing method thereof.

  An ink jet recording head applied to an ink jet recording method (liquid jet recording method) is generally a fine discharge port (orifice), a liquid flow path leading to it, and a discharge pressure generation provided in a part of the liquid flow path. A plurality of discharge pressure generation units including elements are provided. As the discharge pressure generating element, for example, an electrothermal conversion element is used, and in this ink jet recording head, a drive signal is applied to the electrothermal conversion element, whereby the electrothermal conversion element suddenly exceeds the nucleate boiling of the ink. A temperature rises to cause bubbles in the ink, and ink droplets are ejected by the pressure generated at this time. A drive signal is applied to each electrothermal conversion element in accordance with recording information, whereby ink is selectively ejected from each ejection port.

  By the way, among the inkjet heads used in this method, a so-called side shooter type in which droplets are ejected in a vertical direction with respect to a substrate on which an energy generating element for generating energy used for ink ejection is formed. Inkjet heads are known.

  In an ink jet recording head, high throughput is desired. For this purpose, in order to increase the ejection frequency (driving frequency), it is necessary to refill the ink in the flow path after droplet ejection, that is, to refill the ink quickly. In order to speed up the refill, it is desired to reduce the flow resistance of the ink supply path from the supply port to the discharge port.

  As a configuration for reducing the flow resistance of the ink supply path, Patent Document 1 and Patent Document 2 describe an inkjet in which the flow path height near the supply port is higher than the flow path height near the discharge pressure generating element. A recording head and a manufacturing method thereof have been proposed. In the manufacturing methods described in these publications, the height of the flow path in the vicinity of the supply port is increased by digging a corresponding portion of the substrate between the vicinity of the supply port and the vicinity of the discharge pressure generating element. This increases the cross-sectional area of the ink supply path, thus reducing its flow resistance. As described above, the manufacturing methods described in these publications are effective techniques for realizing high throughput.

  On the other hand, such an ink jet recording head is also required to have high reliability. One of the problems is that non-ejection, oblique ejection, etc. that occur because dust mixed in the ejected liquid enters the vicinity of the ejection port or the ejection pressure generation section and affects the flow of liquid during ejection. There is a defect. In contrast, many types of filters have been proposed and used.

  In particular, in a configuration in which a filter is present near the discharge pressure generating section, the discharge pressure reaches the filter when the discharge pressure is generated, and the trapped dust is pushed back so that the filter is completely visible even when used for a long time. There is an advantage that it will not clog. For such a side shooter type ink jet recording head, a columnar filter perpendicular to the substrate, a comb-like filter, a weir-like filter, etc. are usually proposed and used between the supply port and the discharge pressure generating unit. And achieves high reliability.

However, in such a configuration, the area of the filter surface (surface parallel to the filter eye) is limited by the height of the liquid flow path. In order to achieve high throughput, it is desirable to make the filter surface large in order to reduce the flow resistance. However, this configuration does not allow a sufficient area, and the filter is coarsened, that is, the interval between columns is increased. As a result, the flow resistance may have to be reduced at the expense of the performance as a filter.
JP-A-10-095119 Japanese Patent Laid-Open No. 10-034928

  The problem to be solved by the present invention is that the filter has a sufficiently fine mesh, and the presence of the filter in the vicinity of the discharge pressure generating portion ensures that the filter will not be completely clogged while being highly reliable. An object of the present invention is to provide an ink jet recording head having a low flow resistance from the mouth to the ejection port and a high throughput.

  In order to solve the above problems, the present invention proposes the following.

A supply port through which liquid is supplied from the outside, a discharge port through which the liquid is discharged, a liquid flow path that communicates with the discharge port and guides the liquid supplied from the supply port to the discharge port, and the liquid A discharge pressure generating unit that is provided in a part of the flow path and generates a pressure for discharging the liquid, and the supply port forms a discharge pressure generating element that constitutes the discharge pressure generating unit. A substrate for an ink jet recording head used for manufacturing an ink jet recording head formed as a through hole in a substrate,
A portion of the surface of the base on which the discharge pressure generating element is formed is dug in the vicinity of the discharge pressure generating element, and a recessed portion in which the through hole is formed in a part thereof;
An ink jet recording head having a filter layer having a plurality of holes formed between the recess and the liquid flow path.

  In other words, this head is recessed from the supply port to the vicinity of the discharge pressure generating element, reduces the flow resistance from the supply port to the discharge port, and has a recessed portion from the upper surface of the supply port with the filter surface parallel to the substrate surface. By widening up to the upper surface, the flow resistance can be prevented from increasing even if the filter has a sufficiently fine mesh.

A supply port through which liquid is supplied from the outside, a discharge port through which the liquid is discharged, a liquid flow path that communicates with the discharge port and guides the liquid supplied from the supply port to the discharge port, and the liquid A discharge pressure generating unit that is provided in a part of the flow path and generates a pressure for discharging the liquid, and the supply port forms a discharge pressure generating element that constitutes the discharge pressure generating unit. A method of manufacturing an ink jet recording head formed as a through hole in a substrate,
1. 1. A filter layer is formed on the surface of the substrate on which the discharge pressure generating element is formed. 2. Form holes or slits in the filter layer. 3. Isotropic etching is performed on the substrate through the holes or slits to form recesses. 4. An orifice plate having a discharge port and a liquid flow path is formed on the substrate. An ink jet recording head comprising: forming a supply port by patterning a resist on a surface opposite to a resin-coated surface of a substrate, and performing etching until the substrate is connected to the recess from the opening. It is a manufacturing method.

  The isotropic etching may be chemical dry etching, wet etching with hydrofluoric acid, nitric acid, or a mixture thereof, or etching with xenon difluoride or other reactive gas.

  In addition, in step 3 above. It is also conceivable that a protective layer is formed on the inner surface of the recess after passing through the holes or slits of the filter layer and that the protective layer at the connecting portion between the recess and the supply port is removed after the step 5.

  In this way, even when acidic or alkaline liquid is discharged, the surface of the dent portion can be protected from being corroded, and at the same time, when the dent portion and the supply port are connected in Step 5 above. In addition, it is possible to prevent the corner portion from being rapidly etched and the shape from collapsing.

  The following manufacturing method is also proposed.

A supply port through which liquid is supplied from the outside, a discharge port through which the liquid is discharged, a liquid flow path that communicates with the discharge port and guides the liquid supplied from the supply port to the discharge port, and the liquid A discharge pressure generating section that is provided in a part of the flow path and generates a pressure for discharging the liquid, and the supply port forms a discharge pressure generating element that constitutes the discharge pressure generating section. A method of manufacturing an ink jet recording head formed as a through hole in a substrate,
1. 1. A filter layer is formed on the surface of the substrate where the discharge pressure generating element is formed. 2. A resist is patterned on the surface of the substrate opposite to the surface on which the filter layer exists, and etching is performed from the opening to the filter layer to form a supply port. 3. Form holes or slits in the filter layer. 4. Isotropic etching is performed on the substrate through the holes or slits to form recesses. An inkjet recording head manufacturing method comprising a step of forming an orifice plate having a liquid flow path and a discharge port on the substrate.

  The isotropic etching may be chemical dry etching, wet etching with hydrofluoric acid, nitric acid, or a mixture thereof, or etching with xenon difluoride or other reactive gas.

  Furthermore, the following manufacturing method is also proposed.

A supply port through which liquid is supplied from the outside, a discharge port through which the liquid is discharged, a liquid flow path that communicates with the discharge port and guides the liquid supplied from the supply port to the discharge port, and the liquid A discharge pressure generating unit that is provided in a part of the flow path and generates a pressure for discharging the liquid, and the supply port forms a discharge pressure generating element that constitutes the discharge pressure generating unit. A method of manufacturing an ink jet recording head formed as a through hole in a substrate,
1. 1. A layer serving as a filter is formed on the surface of the plate where the discharge pressure generating element is formed. 2. Form holes or slits in the filter layer. 3. An orifice plate having a liquid flow path and a discharge port is formed on the substrate. 4. A resist is patterned on the surface of the substrate opposite to the surface on which the filter layer is present, and etching proceeds from the opening to the filter layer to form a supply port. An ink jet recording head manufacturing method comprising a step of introducing an etchant through the discharge port, a liquid flow path, a hole or a slit of a filter layer, performing isotropic etching on a substrate, and forming a recess. is there.

  In this manufacturing method, since the orifice plate is provided before forming the recess and the supply port in the substrate, a solvent coat can be used for forming the orifice plate.

  Further, the isotropic etching may be etching with xenon difluoride or other reactive gas.

  FIG. 12 is a plan view and a cross-sectional view showing an example of a conventional ink jet recording head.

  These ink jet recording heads have high reliability due to the presence of a filter having sufficiently fine eyes in the vicinity of the discharge pressure generating element. Furthermore, since the area of the filter is large and the path from the supply port to the discharge port is wide, the flow resistance is small and the recording head has a high throughput.

  Next, details of the present invention will be described in accordance with the description of the embodiments.

  FIG. 1 is an ink jet recording head diagram that is Embodiment 1 of the present invention.

  2 and 3 are cross-sectional views showing a method of manufacturing the ink jet recording head that is Embodiment 1 of the present invention.

  A heating resistor as a discharge pressure generating element and its drive circuit (not shown) are formed on a silicon substrate by a general-purpose semiconductor process. In addition, SiO used as an insulating layer in the drive circuit is arranged so as to extend over the position where the recess is formed (FIG. 2-a).

  A resist is applied on the substrate and patterned by photolithography.

  By dipping in BHF, a plurality of holes are formed in the SiO at the recess formation position, and this is used as a filter.

  The resist was peeled off once, the resist was laminated on the surface of the substrate, and the resist was solvent coated on the back surface.

  The resist on the filter area is removed by photolithography.

  Silicon under the filter is isotropically etched with XeF2 gas to form a recess (Fig. 2-c).

  A resist capable of eluting with polymethylisopropenyl ketone as a main material is laminated and patterned by photolithography to form a liquid flow path mold (FIG. 2-d).

  A resist, which is a cationic polymerization type epoxy resin, is applied thereon, and a discharge port is patterned by a photolithographic technique to form an orifice plate (FIG. 3-a).

  The surface of the substrate on the orifice plate side is coated with cyclized rubber, and the back surface is coated with a resist.

  After patterning the resist on the back surface by photolithography technology, the resist is immersed in an aqueous tetramethylammonium hydroxide solution, reaches the recess from the opening of the resist, and further proceeds from the recess to the inner surface (see FIG. 3). b).

  The cyclized rubber is removed with xylene, and the resist on the back surface is also removed.

  After exposing the mold material of the liquid flow path through the orifice plate, ultrasonic waves are applied while being immersed in methyl lactate to remove it.

  The substrate is cut out by a dicer to obtain the ink jet recording head of the present invention (FIG. 3-c).

  FIG. 4 is an ink jet recording head diagram that is Embodiment 2 of the present invention.

  5 and 6 are cross-sectional views showing a method of manufacturing an ink jet recording head that is Embodiment 2 of the present invention.

  A heating resistor and its drive circuit (not shown) are formed on a silicon substrate. In addition, a Ta layer that protects the heating resistor from cavitation of the discharged liquid is disposed so as to extend over the position where the recess is formed.

  Resist is applied to both sides of the substrate, and the back side is patterned by photolithography.

  It is immersed in an aqueous tetramethylammonium hydroxide solution, and etching is advanced until it reaches the Ta layer on the surface from the opening of the resist (FIG. 5-a).

  After the resist is peeled off, the resist is applied again on the substrate and patterned by photolithography.

  A plurality of holes are formed in the Ta layer at the recess formation position by chemical dry etching, and this is used as a filter.

  Once the resist is removed, the resist is applied to the substrate surface, and UV tape is applied to the back surface.

  The resist on the filter area is removed by photolithography.

  Silicon under the filter is isotropically etched with XeF2 gas to form a recess (FIG. 5-c).

  An elution resist mainly composed of polymethylisopropenyl ketone is laminated and patterned by photolithography to form a liquid flow path mold (FIG. 5-d).

  A resist, which is a cationic polymerization type epoxy resin, is applied thereon, and the discharge port is patterned by a photolithographic technique to form an orifice plate (FIG. 6-a).

  After exposing the mold material of the liquid flow path through the orifice plate, ultrasonic waves are applied while being immersed in methyl lactate to remove it.

  The substrate is cut out by a dicer to obtain the ink jet recording head of the present invention (FIG. 6B).

  In this embodiment, since the supply port is formed before forming the orifice plate on the substrate, there is no step of protecting the orifice plate with the cyclized rubber, and a low-cost recording head can be obtained.

  7 and 8 are cross-sectional views showing a method of manufacturing an ink jet recording head that is Embodiment 3 of the present invention.

  A heating resistor and its drive circuit (not shown) are formed on a silicon substrate. In addition, a Ta layer that protects the heating resistor from cavitation of the ejected liquid is disposed so as to extend over the position where the recess is formed (FIG. 7A).

  After the resist is peeled off, the resist is applied again on the substrate and patterned by photolithography.

  A plurality of holes are formed in the Ta layer at the recess formation position by chemical dry etching, and this is used as a filter.

  Strip the resist on the substrate.

  An elution resist mainly composed of polymethylisopropenyl ketone is laminated and patterned by photolithography to form a liquid flow path mold (FIG. 7-c).

  A resist, which is a cationic polymerization type epoxy resin, is applied thereon, and the discharge port is patterned by photolithography to form an orifice plate.

  The surface of the substrate on the orifice plate side is coated with cyclized rubber, and the back surface is coated with a resist.

  After patterning the resist on the back surface by a photolithographic technique, it is immersed in an aqueous tetramethylammonium hydroxide solution, and etching is advanced from the resist opening until it reaches the Ta layer on the substrate surface (FIG. 8-a).

  The cyclized rubber is removed with xylene, and the resist on the back side is also peeled off.

  After exposing the mold material of the liquid flow path through the orifice plate, ultrasonic waves are applied while being immersed in methyl lactate to remove it (FIG. 8-b).

  Silicon under the filter is isotropically etched with XeF2 gas to form a recess (FIG. 8-c).

  It cuts out from a board | substrate with a dicer and obtains the inkjet recording head of this invention.

  In this embodiment, since the orifice plate is formed before the depression is formed on the substrate, the liquid channel mold can be solvent-coated. Thus, if there is a coater that can apply a plurality of types of chemical solutions, it is not necessary to prepare a separate laminating apparatus. In consideration of manufacturing a plurality of types of heads on the same line, the solvent coating is more cost effective than the laminating method in which a film must be prepared for each film thickness.

  FIG. 9 is an ink jet recording head diagram that is Embodiment 4 of the present invention.

  10 and 12 are cross-sectional views showing a method of manufacturing an ink jet recording head that is Embodiment 4 of the present invention.

  A heating resistor as a discharge pressure generating element and its drive circuit (not shown) are formed on a silicon substrate by a general-purpose semiconductor process. Further, SiO used as an insulating layer in the drive circuit is arranged so as to extend over the position where the recess is formed (FIG. 10-a).

  A resist is applied on the substrate and patterned by photolithography.

  By dipping in BHF, a plurality of holes are formed in the SiO at the recess formation position, and this is used as a filter.

  The resist was peeled off once, the resist was laminated on the surface of the substrate, and the resist was solvent coated on the back surface.

  The resist on the filter area is removed by photolithography.

  Silicon under the filter is isotropically etched with XeF2 gas to form a recess (FIG. 10-c).

  After the resist is peeled off, SiN serving as a protective layer is formed on the substrate surface including the inner surface of the depression by plasma CVD.

  The resist is coated with a laminate, and the resist other than the region where the filter holes are distributed is removed by photolithography.

  By chemical dry etching, SiN in the region not protected by the resist other than the inner surface of the recess is removed, and the resist is peeled off (FIG. 10-d).

  A resist capable of eluting containing polymethylisopropenyl ketone as a main material is laminated and patterned by photolithography to form a liquid flow path mold.

  A resist, which is a cationic polymerization type epoxy resin, is applied thereon, and the discharge port is patterned by photolithography to form an orifice plate (FIG. 11-a).

  The surface of the substrate on the orifice plate side is coated with cyclized rubber, and the back surface is coated with a resist.

  After patterning the resist on the back side by photolithography, it is immersed in tetramethylammonium hydroxide aqueous solution, reaches the recess from the resist opening, and further proceeds from the recess to the SiN on the inner surface. 11-b).

  By introducing an etchant from the supply port by chemical dry etching, SiN in the connection portion between the supply port and the depression is removed.

  The cyclized rubber is removed with xylene, and the resist on the back surface is also removed.

  After exposing the mold material of the liquid flow path through the orifice plate, ultrasonic waves are applied while being immersed in methyl lactate to remove it.

  It cuts out from a board | substrate with a dicer and obtains the inkjet recording head of this invention (FIG. 11-c).

  In this embodiment, a protective layer is present on the inner surface of the recess, and the substrate is not etched even when the liquid to be discharged is not neutral.

  At the same time, when the supply port and the recess are connected, the corner of the substrate is rapidly etched and the shape does not collapse, so that a highly accurate recess shape can be obtained.

1 is an inkjet recording head diagram that is Embodiment 1 of the present invention. FIG. Sectional drawing which shows the first half of the manufacturing method of the inkjet recording head which is Example 1 of this invention. Sectional drawing which shows the production method latter half of the inkjet recording head which is Example 1 of this invention. FIG. 6 is a perspective sectional view of an ink jet recording head that is Embodiment 2 of the present invention. Sectional drawing which shows the first half of the manufacturing method of the inkjet recording head which is Example 2 of this invention. Sectional drawing which shows the production method latter half of the inkjet recording head which is Example 2 of this invention. Sectional drawing which shows the first half of the manufacturing method of the inkjet recording head which is Example 3 of this invention. Sectional drawing which shows the latter half of the manufacturing method of the inkjet recording head which is Example 3 of this invention. FIG. 6 is an inkjet recording head diagram that is Embodiment 4 of the present invention. Sectional drawing which shows the first half of the manufacturing method of the inkjet recording head which is Example 4 of this invention. Sectional drawing which shows the latter half of the manufacturing method of the inkjet recording head which is Example 4 of this invention. FIG. 2 is a plan view and a cross-sectional view illustrating an example of a conventional ink jet recording head.

Claims (11)

A supply port through which liquid is supplied from the outside, a discharge port through which the liquid is discharged, a liquid flow path that communicates with the discharge port and guides the liquid supplied from the supply port to the discharge port, and the liquid A discharge pressure generating unit that is provided in a part of the flow path and generates a pressure for discharging the liquid, and the supply port forms a discharge pressure generating element that constitutes the discharge pressure generating unit. A substrate for an ink jet recording head used for manufacturing an ink jet recording head formed as a through hole in a substrate,
A portion of the surface of the base on which the discharge pressure generating element is formed is dug in the vicinity of the discharge pressure generating element, and a recess portion in which the through-hole is formed;
An ink jet recording head having a filter layer in which a plurality of holes or slits are formed between the recess and the liquid flow path.   2. The ink jet recording head according to claim 1, wherein the filter layer is a layer common to an insulating layer, a passivation layer, and other functional layers of a driving circuit of the ejection pressure generating element.   2. The ink jet recording according to claim 1, wherein a protective layer which is resistant to SiN, SiO, and other common liquid chambers and to acids and alkalis used in the liquid is formed on the inner surface of the recess. head. A supply port through which liquid is supplied from the outside, a discharge port through which the liquid is discharged, a liquid flow path that communicates with the discharge port and guides the liquid supplied from the supply port to the discharge port, and the liquid A discharge pressure generating unit that is provided in a part of the flow path and generates a pressure for discharging the liquid, and the supply port forms a discharge pressure generating element that constitutes the discharge pressure generating unit. A method of manufacturing an ink jet recording head formed as a through hole in a substrate,
Forming a filter layer on the surface of the substrate on which the discharge pressure generating element is formed;
Forming a hole or slit in the filter layer;
Performing isotropic etching on the substrate through the hole or slit to form a recess,
Forming an orifice plate having a discharge port and a liquid flow path on the substrate;
And a step of patterning a resist on a surface of the substrate opposite to the surface coated with the resin, and forming a supply port by performing etching until the resist is connected to the recess from the opening. Manufacturing method.   5. The method according to claim 4, wherein the isotropic etching is chemical dry etching, wet etching with hydrofluoric acid, nitric acid, or a mixture thereof, or etching with xenon difluoride or other reactive gas. A method for manufacturing an inkjet recording head.   After the step of forming the recess, a protective layer is formed on the inner surface of the recess through the hole or slit of the filter layer, and after the step of forming the supply port, the protective layer at the connecting portion of the recess and the supply port is formed. The method of manufacturing an ink jet recording head according to claim 4, wherein the ink jet recording head is removed. A supply port through which liquid is supplied from the outside, a discharge port through which the liquid is discharged, a liquid flow path that communicates with the discharge port and guides the liquid supplied from the supply port to the discharge port, and the liquid A discharge pressure generating unit that is provided in a part of the flow path and generates a pressure for discharging the liquid, and the supply port forms a discharge pressure generating element that constitutes the discharge pressure generating unit. A method of manufacturing an ink jet recording head formed as a through hole in a substrate,
Forming a filter layer on the surface of the substrate on which the discharge pressure generating element is formed;
Patterning a resist on the surface of the substrate opposite to the surface on which the filter layer is present, and forming a supply port by performing etching from the opening to the filter layer;
Forming a hole or slit in the filter layer;
Performing isotropic etching on the substrate through the hole or slit to form a recess,
Forming an orifice plate having a liquid flow path and a discharge port on the substrate; and a method of manufacturing an ink jet recording head.   8. The isotropic etching according to claim 7, wherein the isotropic etching is chemical dry etching, wet etching with hydrofluoric acid, nitric acid, or a mixture thereof, or etching with xenon difluoride or other reactive gas. A method for manufacturing an inkjet recording head.   8. The method of manufacturing an ink jet recording head according to claim 7, further comprising a step of forming a protective layer on the recess and the supply port inner surface after the step of forming the recess. A supply port through which liquid is supplied from the outside, a discharge port through which the liquid is discharged, a liquid flow path that communicates with the discharge port and guides the liquid supplied from the supply port to the discharge port, and the liquid A discharge pressure generating unit that is provided in a part of the flow path and generates a pressure for discharging the liquid, and the supply port forms a discharge pressure generating element that constitutes the discharge pressure generating unit. A method of manufacturing an ink jet recording head formed as a through hole in a substrate,
Forming a filter layer on the surface of the substrate on which the discharge pressure generating element is formed;
Forming a hole or slit in the filter layer;
Forming an orifice plate having a liquid flow path and a discharge port on the substrate;
Patterning a resist on the surface of the substrate opposite to the surface on which the filter layer is present, and forming a supply port by performing etching from the opening to the filter layer;
And a step of introducing an etchant through the discharge port, the liquid flow path, the hole or slit of the filter layer, performing isotropic etching on the substrate, and forming a recess. .   The method of manufacturing an ink jet recording head according to claim 10, wherein the isotropic etching is etching with xenon difluoride or other reactive gas.

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