JP2007301896A - Droplet ejection head, droplet ejector, and manufacturing method for them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a stable high-density droplet ejection head, a droplet ejector, and a method which enables an efficient manufacture. <P>SOLUTION: This droplet ejection head comprises: a cavity substrate 3 which is equipped with a diaphragm 32 for pressurizing a liquid, and which has a plurality of first recesses 31a of an ejection chambers 31, partially constituting the ejection chambers 31; a channel substrate 2 which is formed perpendicularly to a bottom surface, in which a plurality of through-holes communicating with the ejection chambers 31, respectively, are provided as supply ports 32, which communicate with a reservoir recess 22a serving as a reservoir 22 for storing the liquid for being supplied to the respective ejection chambers 31, and the plurality of ejection chambers 31, and which is provided with a plurality of nozzles 21 for ejecting the liquid, pressurized by the diaphragm 32, as a liquid droplet; and a cover plate 1 which covers an opening part of the recess 22a, and which constitutes a part of a wall of the reservoir 22. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a droplet discharge head, a droplet discharge device having a droplet discharge head, and the like.

  The droplet discharge method (typically, there is an inkjet used for printing by discharging ink) is used for printing (printing) in all fields regardless of household use or industrial use. Yes. In the droplet discharge method, for example, a droplet discharge head having a plurality of nozzles, which are microfabricated elements, is moved relative to an object and the liquid is discharged to a predetermined position of the object. In addition, for the production of display devices using liquid crystals (Liquid Crystal), display substrates using organic electroluminescence (hereinafter referred to as OEL) elements, DNA, biomolecule microarrays, etc. Is also used.

As a discharge head that realizes the droplet discharge method, at least one wall of a liquid chamber that stores discharge liquid is bent, the shape is changed, the liquid is pressurized, and the liquid is dropped from a nozzle that communicates with the liquid chamber. There is something to be discharged. At this time, there is one that forms a nozzle, a flow path to the nozzle, and the like by performing fine processing such as etching on the substrate (see, for example, Patent Document 1).
JP 2003-326724 A

When manufacturing the droplet discharge head as described above, a flow path substrate on which a flow path is formed, for example, a discharge port (nozzle) portion is formed of a silicon oxide (SiO ₂ ) film. However, considering the meniscus control and the like, it is considered that the discharge port needs a predetermined length (about 10 μm or more), and forming a silicon oxide film having a thickness to obtain the length is In terms of time and cost, it is inefficient. In addition, since the reservoir for storing the liquid supplied to each discharge chamber is formed on the side of the joint surface with the substrate having the pressurizing means, there is a disadvantage that the head area becomes large.

  Accordingly, an object of the present invention is to solve the above problems, to obtain a stable and high-density droplet discharge head and apparatus, and to obtain a method that can be efficiently manufactured.

A droplet discharge head according to the present invention includes a cavity substrate having a plurality of first recesses that are part of a discharge chamber provided with a vibration plate for pressurizing a liquid, and a first recess formed by joining the cavity substrate. One of the reservoirs for forming the discharge chambers and having a plurality of supply ports formed in the bottom surface thereof in communication with the discharge chambers and penetrating so that the axis is perpendicular to the substrate. A flow path substrate having a plurality of nozzles that communicate with the second recesses and the discharge chambers, and that are formed so as to be perpendicular to the substrate and that discharge the liquid pressurized by the diaphragm as droplets And a cover plate covering the opening of the second recess.
According to the present invention, a nozzle having a shaft penetrating in a vertical direction and a concave portion serving as a reservoir are formed on the same flow path substrate, and the concave portion is covered by an inexpensive cover plate to form a reservoir. Therefore, it is not necessary to form the nozzle or a part thereof on another substrate such as silicon, so that time and material costs can be reduced. Further, since the concave portion is formed on the cover plate side, it can be three-dimensionally intersected with each discharge chamber, and the head area can be reduced. By forming a supply port having a bottom surface in the recess and having a shaft penetrating in the vertical direction, the flow resistance of the liquid and the like can be controlled by adjusting the diameter of the supply port.

In addition, the droplet discharge head according to the present invention forms a stepped or tapered nozzle so that the nozzle diameter decreases from the contact surface side with the cavity substrate toward the droplet discharge side.
According to the present invention, the nozzle is formed in a stepped or tapered manner in order to reduce the diameter of the nozzle on the side from which droplets are discharged. For example, the flow path resistance increases even if the nozzle length is increased. Can be prevented. Further, the straightness of the droplet can be improved by the rectifying action.

In addition, the flow path substrate of the droplet discharge head according to the present invention has a plurality of third recesses serving as a part of the discharge chamber on the side in contact with the cavity substrate.
According to the present invention, by providing the third recess, for example, even if the cavity substrate is made thinner, the volume of the first recess that is reduced by the cavity substrate can be compensated, and the volume of the entire discharge chamber can be increased. Thereby, the flow path resistance of the entire droplet discharge head can be reduced, and a droplet discharge head having a high nozzle density and excellent discharge characteristics can be obtained.

In the droplet discharge head according to the present invention, the cover plate is a frame, and a flexible film is provided in the frame.
According to the present invention, the flexible film can be used as a diaphragm that buffers the pressure applied to the liquid in the reservoir by the vibration plate (reduces compliance). Therefore, unnecessary discharge and insufficient supply of liquid due to pressure interference between the discharge chambers via the reservoir can be prevented.

The flow path substrate of the droplet discharge head according to the present invention is made of single crystal silicon.
According to the present invention, since the flow path substrate is made of single crystal silicon, it is possible to perform high-precision processing using the MEMS technology (semiconductor manufacturing process step) when processing the channel substrate. In particular, wet etching using crystal plane orientation is frequently used, and for example, an extra-thick oxide film formation or the like is not performed, and it can be manufactured without requiring time-consuming and costly processes.

The cover plate of the droplet discharge head according to the present invention is made of SUS.
According to the present invention, since SUS is used as the material of the cover plate, a thin plate that does not affect the landing accuracy from the discharge port to the discharge target can be manufactured at low cost.

In the droplet discharge head according to the present invention, the flexible film is made of polyphenylene sulfide.
According to the present invention, since the flexible film is made of polyphenylene sulfide, it is excellent in chemical resistance and moisture permeability, and a long-life droplet discharge head can be manufactured.

A droplet discharge device according to the present invention is equipped with the above-described droplet discharge head.
According to the present invention, it is possible to obtain a droplet discharge device that includes a stable and high-density droplet discharge head and is efficient in terms of time and cost.

Further, in the method for manufacturing a droplet discharge head according to the present invention, a recess serving as a reservoir for storing liquid to be supplied to a plurality of discharge chambers provided with a vibration plate that pressurizes the liquid is formed and processed into a single crystal silicon substrate by wet etching, In order to communicate between each discharge chamber and the reservoir, a supply port provided on the bottom of the recess and each discharge chamber communicate with each discharge chamber, and each nozzle that discharges pressurized liquid as droplets is formed and processed on the substrate by dry etching. A flow path substrate is produced.
According to the present invention, nozzles and supply ports that need to be processed with high accuracy and a high aspect ratio are improved in discharge performance by using dry etching, and have a large area and a recess serving as a reservoir with a large amount of etching. Since wet etching is used, multiple substrates (wafers) can be immersed at the same time, processing can be performed, throughput can be increased, and time and cost costs can be reduced. it can.

In addition, the method for manufacturing a droplet discharge head according to the present invention provides a cover plate having a recess opening portion so that a cover plate made of a frame having a flexible film provided in the frame is a part of the reservoir. The method further includes a covering step.
According to the present invention, the concave portion is covered with the cover plate to form a part of the reservoir, and the cover plate is provided with a flexible film, so that the pressure applied to the liquid in the reservoir is buffered by the vibration plate ( It can be used as a diaphragm (which reduces compliance), and can prevent unnecessary discharge and insufficient supply of liquid due to pressure interference between discharge chambers via a reservoir.

Further, in the method for manufacturing a droplet discharge head according to the present invention, the substrate to be the flow path substrate is fixed to the support substrate during or after the formation process in the manufacture of the flow path substrate, and is ground until a desired thickness is obtained. Or it has the process of grind | polishing.
Further, according to the present invention, the substrate that is the material of the flow path substrate is a thick substrate before processing, and is fixed to the support substrate during or after the forming process, and is made to have a desired thickness by grinding or the like. Therefore, it is possible to use a silicon substrate having a thickness that enables stable handling and the like, and it is possible to reduce cracks due to handling of the silicon substrate processing during the production of the flow path substrate and improve the yield. In addition, by using standard products, member costs can be suppressed, and it is possible to easily cope with specification changes such as substrate thickness changes.

The manufacturing method of the droplet discharge device according to the present invention applies the above-described manufacturing method of the droplet discharge head to manufacture the droplet discharge device.
According to the present invention, when manufacturing a flow path substrate, dry etching is performed on necessary portions to improve accuracy, and wet etching is performed on portions where the etching amount is large, thereby reducing the process time and reducing the number of steps. Thus, it is possible to manufacture a droplet discharge device using a droplet discharge head with reduced cost.

Embodiment 1 FIG.
FIG. 1 is an exploded view of a droplet discharge head according to Embodiment 1 of the present invention. 2 is a longitudinal sectional view of the droplet discharge head, and FIG. 3 is a transverse sectional view. 1, 2, and 3 show a part of a droplet discharge head (note that the components are shown in the following drawings, including FIGS. 1 to 3, for the sake of clarity. The relationship may be different from the actual one, and the upper side of the figure is the upper side and the lower side is the lower side).

  As shown in FIG. 1, the droplet discharge head according to the present embodiment is configured by laminating a cover plate 1, a flow path substrate 2, a cavity substrate 3, and an electrode substrate 4. Here, the electrode substrate 4 and the cavity substrate 3 are joined by anodic bonding. The cavity substrate 3 and the flow path substrate 2 and the flow path substrate 2 and the cover plate 1 are bonded using an adhesive such as an epoxy resin.

  The cover plate 1 covers an opening of a later-described reservoir recess 22a (reservoir 22), and becomes a part of the wall of the reservoir 22 so that liquid accumulated in the reservoir does not leak. In the present embodiment, the cover plate 1 is configured as a frame having a through hole in the center portion of the plate, and the through hole in the frame is covered with the resin thin film 11. The resin thin film 11 serves as a diaphragm for buffering the pressure applied to the liquid in the reservoir 22 by the vibration of the diaphragm 32 (reducing compliance). Regarding the cover plate 1, in this embodiment, SUS (stainless steel) capable of performing ultrathin processing (for example, about 10 to 50 μm, here 30 μm) at low cost is used as a material. The reason for making it extremely thin is to prevent the cover plate 1 from excessively increasing the distance between the discharge port (nozzle 21) and the discharge target. Further, the resin thin film 11 is made of polyphenylene sulfide (PPS) having flexibility and excellent chemical resistance and moisture permeability resistance.

  The flow path substrate 2 is mainly made of, for example, a silicon single crystal substrate (hereinafter referred to as a silicon substrate). In the flow path substrate 2 of the present embodiment, a silicon substrate having a (100) plane orientation is used as a material. In the flow path substrate 2, a reservoir recess 22 a (second recess) serving as a reservoir (common liquid chamber) 22 for supplying a liquid to each discharge chamber 31 is formed. Further, the bottom surface of the reservoir recess 22a has a through-hole 33c (which communicates with the through-holes 33a and 33b) serving as a part of the liquid supply hole 33 and a supply port for supplying liquid from the reservoir 22 to each discharge chamber 31 ( (Orifice) 23 is formed corresponding to each discharge chamber 31. Here, at least the supply port 23 is formed as a through hole whose axis is perpendicular to the substrate (in this embodiment, the through hole 33c also penetrates in the vertical direction). In the present embodiment, the liquid is supplied to each discharge chamber 31 through one supply port 23, but a plurality of supply ports 23 may be provided for each discharge chamber 31. In the flow path substrate 2 (droplet discharge head) of the present embodiment, the portion that becomes the wall of the reservoir 22 is formed by a recess having a bottom surface instead of a through hole. Therefore, the through-hole 33c and the supply port 23 can be formed as through-holes (holes) oriented in the direction perpendicular to the substrate by the silicon portions left as the bottom surfaces, each having a wall surface. .

  Further, the flow path substrate 2 of the present embodiment has a through hole independent of the reservoir recess 22 a, and this becomes the nozzle 21 that communicates with each discharge chamber 31. The nozzle 21 is also formed as a through hole whose axis is perpendicular to the substrate. Here, in order to improve the discharge performance, for example, by causing the discharged droplet to go straight, the discharge port side that discharges the droplet has a smaller diameter than the supply port side to which the liquid from the discharge chamber 31 is supplied. A tapered or stepped nozzle may be formed. Therefore, in the present embodiment, the nozzle 21 is a two-stage nozzle 21 with a small diameter on the discharge port side. The step formed on the discharge port side is referred to as a first nozzle 21a, and the step formed on the cavity substrate 3 side is referred to as a second nozzle 21b.

  Furthermore, the flow path substrate 2 according to the present embodiment is a discharge chamber constituting a part of the discharge chamber 31 together with the discharge chamber first recess 31a formed in the cavity substrate 3 on the joint surface side with the cavity substrate 3 described later. It has the chamber 2nd recessed part 31b (3rd recessed part). Here, a part of the silicon substrate may be left to partition the discharge chamber second recess 31b and the nozzle 21, but in this embodiment, the flow of the liquid is improved to reduce the channel resistance. In order to make it lower, the discharge chamber second recess 31b and the nozzle 21 are formed so as to be integrated continuously. In addition, a liquid protective film 24 made of silicon oxide is formed on at least a portion of the flow path substrate 2 that becomes a liquid flow path.

The cavity substrate 3 is also mainly made of a silicon substrate. The cavity substrate 3 is formed with a discharge chamber first recess (a bottom wall serving as a movable plate 32 serving as a movable electrode) 31 a to be the discharge chamber 31. Furthermore, a TEOS film (here, Tetraethyl orthosilicate Tetraethoxysilane: Tetraethylsilane) is provided on the lower surface of the cavity substrate 3 (the surface facing the electrode substrate 2) to electrically insulate between the individual electrode 42 and the diaphragm 32 described later. An insulating film 34 which is an SiO ₂ film made of ethoxysilane (ethyl silicate) is formed to a thickness of 0.1 μm using a plasma CVD (Chemical Vapor Deposition: TEOS-pCVD) method. Although the insulating film 34 is a TEOS film here, for example, Al ₂ O ₃ (aluminum oxide (alumina)) or the like may be used. Here, the cavity substrate 3 is also provided with a through hole 33b that is a part of the liquid supply hole 33 (communication with the through hole 33a and the through hole 33c). Further, a common electrode terminal 35 is provided as a terminal for supplying a charge having a polarity opposite to that of the individual electrode 42 from an external power supply means (not shown) to the substrate (diaphragm 32).

  The electrode substrate 4 is mainly made of a substrate such as borosilicate heat-resistant hard glass having a thickness of about 1 mm. In the present embodiment, the glass substrate is used, but single crystal silicon may be used as the substrate, for example. On the surface of the electrode substrate 4, a plurality of recesses 41 having a depth of, for example, about 0.3 μm are formed in accordance with the discharge chamber first recesses 31 a (first recesses) serving as the discharge chambers 31 of the cavity substrate 3. . In addition, inside the recess 41 (particularly at the bottom), an electrode portion 42a serving as an individual electrode is provided so as to face each discharge chamber 31 (the diaphragm 32), and the lead portion 42b and the terminal portion 42c are integrated. (Hereinafter, these are collectively described as the individual electrode 42 unless it is necessary to distinguish between them.) Between the diaphragm 32 and the individual electrode 42, a certain gap (gap) 41 a that allows the diaphragm 32 to bend (displace) is formed by the recess 41. The individual electrode 42 is formed by depositing ITO (Indium Tin Oxide: indium tin oxide) with a thickness of 0.1 μm inside the recess 41 by, for example, sputtering. In addition, the electrode substrate 2 is provided with a through hole 33a that is a part of the liquid supply hole 33 that becomes a flow path for taking in liquid supplied from an external tank (not shown). Further, the sealing material 43 is provided to block the gap 41a from the outside air and prevent moisture, foreign matter and the like from entering the gap 41a.

  4 and 5 are diagrams showing a manufacturing process of the flow path substrate 2 of the droplet discharge head according to the first embodiment. A method for manufacturing the flow path substrate 2 will be described with reference to FIGS. In practice, a plurality of flow path substrates 2 are formed simultaneously in wafer units, but only a part of them is shown in FIGS.

  For example, an etching mask 42 made of silicon oxide, for example, 1.6 μm is formed on the entire surface of a silicon substrate 51 (hereinafter referred to as the silicon substrate 51) having a thickness of about 525 μm and a surface of (100) orientation by wet thermal oxidation or the like. Hereinafter, in the silicon substrate 41, the bonding surface with the cavity substrate 3 is referred to as a C surface, and the liquid ejection surface by the nozzle 21 is referred to as an N surface.

  The silicon substrate 51 is patterned on the C-side surface and etched with a hydrofluoric acid solution or the like, whereby the nozzle 21, the discharge chamber second recess 31b, and the through hole 33c (liquid supply hole 33) are formed on the silicon substrate 51. Then, the portion of the etching mask 52 corresponding to the supply port 14 is removed (FIG. 4A).

  Regarding the removal, all of the etching mask 52 corresponding to the first nozzle 21a is removed to expose the surface of the silicon substrate 51, but corresponds to the second nozzle 21b supply port 23, the through hole 33c, and the discharge chamber second recess 31b. For the portion, half etching is performed while leaving a part of the etching mask 52. Further, regarding the thickness of the etching mask 23 left in the portion corresponding to the second nozzle 21b, the supply port 23, the through hole 33c, and the discharge chamber second recess 31b for performing half etching (the portion corresponding to the first nozzle 21a) <) A portion corresponding to the second nozzle 21b <A portion corresponding to the discharge chamber second recess 31b = A portion corresponding to the supply port 23 = A portion corresponding to the through hole 33c. Here, it is assumed that the relationship is as described above. However, for example, a portion corresponding to the discharge chamber second recess 31b <a portion corresponding to the supply port 23 may be used. Further, the through hole 33c is etched not on the entire surface of the hole but on the peripheral portion.

Further, dry etching using, for example, ICP (Inductively Coupled Plasma) discharge or the like is performed on the portion corresponding to the first nozzle 21a from the C surface side to form a hole having a depth (height) of about 50 μm. FIG. 4 (b)). Here, as long as the silicon substrate 51 can be etched vertically, the type of dry etching and the type of process gas (for example, sulfur hexafluoride (SF ₆ )) are not particularly limited.

  Then, half etching of the etching mask is performed. Here, all the portions corresponding to the first nozzle 21a are removed to expose the surface of the silicon substrate 51, and the portions corresponding to the supply port 23, the through hole 33c, and the discharge chamber second recess 31b are part of the etching mask 52. Leave a part. Then, for the portion corresponding to the second nozzle 21b, dry etching such as ICP discharge is performed by about 50 μm from the C surface side (FIG. 4C). Here, the portion corresponding to the first nozzle 21a is dry-etched by about 100 μm.

  Further, half etching of the etching mask is performed to remove all of the etching mask 52 corresponding to the supply port 23, the through hole 33c, and the discharge chamber second recess 31b, and the silicon substrate 51 is exposed. Then, dry etching such as ICP discharge is performed for about 40 μm from the C surface side (FIG. 4D). Thereby, the supply port 23 and the discharge chamber second recess 31b are formed.

  When dry etching is completed, the etching mask 52 is etched away with a hydrofluoric acid solution or the like. An etching mask 53 having a thickness of about 1.0 μm is formed on the silicon substrate 51 from which the etching mask 52 has been peeled off using silicon oxide formed by wet thermal oxidation or the like again. Then, in order to wet-etch the portion corresponding to the concave portion 54 that partially becomes the reservoir concave portion 22a (reservoir 22), the etching mask 53 in the portion that becomes the concave portion 54 is removed on the N surface side (FIG. 5E). .

  Next, it is immersed in, for example, an aqueous potassium hydroxide (KOH) solution to form a recess 54 having a depth of about 500 μm (FIG. 5F). A part of the recess 54 becomes the reservoir recess 22a. Here, a plurality of types of potassium hydroxide aqueous solutions having different concentrations of potassium hydroxide are prepared, and by immersing in order from the higher concentration to the lower concentration, the balance between etching rate and surface roughness suppression is achieved. You may do it.

  When the wet etching is completed, the etching mask 53 is etched and removed with a hydrofluoric acid solution or the like. At this time, silicon remaining in the portion corresponding to the through hole 33c is also removed from the silicon substrate 51, and the through hole 33c is formed. Further, for example, a liquid protective film 24 of about 0.1 μm is formed on the silicon substrate 51 from which the etching mask 53 has been peeled off, for example, by dry oxidation (a kind of thermal oxidation) (FIG. 5G). . Then, the C surface side of the silicon substrate 51 and the support substrate 60 are bonded and fixed with, for example, a double-sided tape, and are ground or polished by about 420 μm from the N surface side (FIG. 5H). Here, grinding is performed.

  FIG. 6 is a diagram illustrating a bonding and peeling process between the silicon substrate 51 and the support substrate 60. In the present embodiment, a borosilicate heat-resistant hard glass substrate having a thickness of about 1 mm is used as the support substrate 60, for example. Further, a double-sided tape 62 provided with UV curable adhesive layers 61 whose adhesive strength (adhesive strength) is weakened by ultraviolet irradiation is used on both sides. First, the double-sided tape 62 is attached to the silicon substrate 51. This may be done in a normal atmosphere. At this time, air is prevented from being sandwiched between the silicon substrate 51 and the double-sided tape 62 by using a roller 63 or the like (FIG. 6A). Next, in a vacuum in a vacuum chamber or the like, the double-sided tape 62 is bonded to the support substrate 60 from the surface opposite to the surface to which the silicon substrate 51 is attached (FIG. 6B). Although the silicon substrate 51 is ground after bonding, the grinding apparatus and method are not particularly limited.

About the board | substrate which finished grinding | polishing, the silicon substrate 51 side is mounted on the vacuum suction jig 64, and is fixed (FIG.6 (c)). Then, the double-sided tape 62 is irradiated with ultraviolet rays (UV) from the support substrate 60 side in a nitrogen (N ₂ ) atmosphere to weaken the adhesive strength, and the support substrate 60, the double-sided tape 62, the silicon substrate 51 (channel substrate 2), Is peeled off (FIG. 6D).

  The cover plate 1 prepared in advance is bonded to the flow path substrate 2 manufactured as described above at a predetermined position on the N surface side (a portion that does not block the nozzle 21) (FIG. 5 (i)). ). Here, for example, the cover plate 1 may be bonded after performing a water repellent treatment such as forming a water repellent film on a droplet discharge port. Then, the cavity substrate 3 and the electrode substrate 4 are laminated and bonded, and dicing is performed, and the bonded body manufactured in units of wafers is separated into each droplet discharge head (head chip). Thereby, the droplet discharge head is completed.

  As described above, according to the first embodiment, the flow path substrate 2 having the nozzle 21 and the reservoir recess 22a is made of a silicon substrate, the reservoir recess 22a is covered with the cover plate 1 made of SUS, and the reservoir 22 Therefore, it is not necessary to manufacture a substrate having a nozzle that requires high processing accuracy on another substrate such as silicon, and time and material costs can be reduced. In addition, the flow path substrate 2 is not time-consuming and costly by performing normal MEMS techniques (semiconductor manufacturing process steps) such as dry etching and wet etching without performing excessive steps such as forming a special thick oxide film. It can be produced without the need for an expensive process. Further, since the reservoir recess 12a is formed on the cover plate side, the reservoir recess 12a can be three-dimensionally intersected with each discharge chamber, and the head area can be reduced. Since the supply port 23 can be formed in the vertical direction on the bottom surface of the reservoir recess 12a, the flow resistance of the liquid and the like can be controlled by adjusting the diameter of the supply port 23. Moreover, since the silicon substrate of the single crystal substrate is used as the material, the highly accurate flow path substrate 2 using a technique such as MEMS can be manufactured.

  Furthermore, since the cover plate 1 is made of SUS, a thin plate that does not interfere with the discharge of droplets from the nozzle 21 can be manufactured at low cost. At this time, the cover plate 1 is used as a frame, and the resin thin film 12 having flexibility is formed in the frame, thereby buffering the pressure applied to the liquid in the reservoir 22 (reducing compliance) and using as a diaphragm. Can do. Therefore, unnecessary discharge and insufficient supply of liquid due to pressure interference between the discharge chambers via the reservoir can be prevented. Further, by using PPS as the material for the resin thin film 11, it is possible to manufacture a droplet discharge head having excellent chemical resistance and moisture permeability and having a long life.

  The nozzle 21 has a two-stage configuration with the first nozzle 21a and the second nozzle 21b, and the nozzle length is reduced by reducing the diameter on the discharge port side from the bonding side (liquid inlet port) with the cavity substrate 3. It is possible to prevent an increase in channel resistance due to an increase in length. In addition, since the discharge chamber second recess 31b, which is a part of the discharge chamber 31, is provided in the flow path substrate 2, the volume of the discharge chamber first recess 31a, which has been reduced by making the cavity substrate 3 thinner, is compensated. The volume of the entire discharge chamber 31 can be increased. Thereby, the flow path resistance of the entire droplet discharge head can be reduced, and a droplet discharge head having a high nozzle density and excellent discharge characteristics can be obtained. By connecting the nozzle and the discharge chamber second recess 31b without partitioning, the flow path resistance can be lowered. On the contrary, it is also possible to actively provide a partition made of silicon, adjust the height of the silicon, and control the channel resistance.

  Further, in manufacturing the flow path substrate 2, the nozzle 21 and the supply port 23 that need to be processed with high accuracy and a high aspect ratio are dry-etched to improve the discharge performance, have a large area, and an etching amount. Since the reservoir recess 22a, which is the reservoir 22 having a large amount, is wet-etched, a plurality of substrates (wafers) can be simultaneously immersed and processed. Therefore, the throughput can be increased, and the time and cost costs can be suppressed. In addition, the silicon substrate 51 that is the material of the flow path substrate 2 is a thick substrate, fixed to the support substrate 60 after processing, and ground to a desired thickness. Can be more effectively prevented. Moreover, since standard goods can also be used, member cost can be suppressed.

Embodiment 2. FIG.
7 and 8 are diagrams showing a manufacturing process of the flow path substrate 2 of the droplet discharge head according to the second embodiment. A method for manufacturing the flow path substrate 2 in the second embodiment will be described with reference to FIGS. For example, an etching mask 72 made of silicon oxide, for example, 1.2 μm is formed on the entire surface of a silicon substrate 71 (hereinafter referred to as silicon substrate 71) having a thickness of about 525 μm and a (100) plane orientation by wet thermal oxidation or the like.

  The N-side surface of the silicon substrate 71 is patterned and etched with a hydrofluoric acid solution or the like, thereby removing the reservoir recess 22a (reservoir 22) and the etching mask 72 corresponding to the first nozzle 21a (FIG. 7 (a)). Here, the etching mask 72 in the portion corresponding to the reservoir recess 22a is completely removed to expose the surface of the silicon substrate 71, but the portion corresponding to the first nozzle 21a is half-etched. Then, for example, it is immersed in an aqueous solution of potassium hydroxide (KOH) to form a reservoir recess 22a having a depth of about 70 μm (FIG. 7B).

  After forming the reservoir recess 22a, the etching mask is half-etched to expose the surface of the silicon substrate 71 at a portion corresponding to the first nozzle 21a. Further, for example, after the reservoir recess 22a is covered and protected with the hard mask 80, the portion corresponding to the first nozzle 21a is dry-etched using, for example, ICP discharge from the N surface side to have a depth of about 30 μm. A hole of (height) is made (FIG. 7C).

  After the etching mask 72 is etched and removed with a hydrofluoric acid solution or the like, a dry oxide film 73 to be the liquid protective film 24 is formed at least on the N surface side by a dry oxidation method, and then the silicon substrate 71 is formed on, for example, a double-sided tape. The N surface side is bonded and fixed to the support substrate 60, and the silicon substrate 71 is ground or polished by about 420 μm from the C surface side (FIG. 7D). In the present embodiment, the N surface side is bonded to the support substrate 60, and grinding or polishing is performed from the C surface side. However, the procedure and the like are the same as those described in the first embodiment. It's okay.

  After grinding, an etching mask 74 is formed on the C-plane side of the silicon substrate 71 (the formation method is not particularly limited, but it is desirable to form a TEOS film using a plasma CVD method). Further, the etching mask 74 is removed by full etching or half etching of the second nozzle 21b, the discharge chamber second recess 31b, the through hole 33c (liquid supply hole 33) and the portion corresponding to the supply port 23 (FIG. 8E). ). Here, as to the thickness of the etching mask 23 in each portion, as in the first embodiment, the portion corresponding to the second nozzle 21b (= 0) <the portion corresponding to the discharge chamber second recess 31b = supply It is assumed that there is a relationship of a portion corresponding to the opening 23 = a portion corresponding to the through hole 33c.

  Then, dry etching using, for example, ICP discharge or the like is performed on the portion corresponding to the second nozzle 21b from the C surface side to form a hole having a depth (height) of about 60 μm (FIG. 8F). ).

  Further, half etching of the etching mask is performed to remove all of the etching mask 73 corresponding to the supply port 23, the through hole 33c, and the discharge chamber second recess 31b, and the silicon substrate 71 is exposed. Then, dry etching such as ICP discharge is performed for about 30 μm from the C surface side (FIG. 8G). At this time, the etching depth of the portion corresponding to the second nozzle 21b is about 90 μm.

  Then, the silicon oxide film (film formed by the dry oxidation method) remaining in the portion corresponding to the second nozzle 21b, the portion corresponding to the supply port 23, and the portion corresponding to the through hole 33c is removed by dry etching, and the penetration Let Further, a TEOS film 75 to be the liquid protective film 24 is formed to a thickness of 0.1 μm by using a plasma CVD method (FIG. 8H). At this time, the remaining etching mask 74 may be left as it is.

  The support substrate 60 and the double-sided tape 62 and the silicon substrate 71 (channel substrate 2) are peeled off, and the channel substrate 2 manufactured as described above is a cover prepared in advance as in the first embodiment. The plate 1 is joined to a predetermined position on the N surface side. Further, the cavity substrate 3 and the electrode substrate 4 are laminated and bonded, and dicing is performed to separate the bonded body manufactured in units of wafers into each droplet discharge head (head chip). Thereby, the droplet discharge head is completed.

  As described above, according to the second embodiment, in manufacturing the flow path substrate 2, the nozzle 21 and the supply port 23 that need to be processed with high accuracy and high aspect ratio are dry-etched to improve the discharge performance. Thus, since the reservoir recess 22a, which is the reservoir 22 having a large area and a large etching amount, is subjected to wet etching, a plurality of substrates (wafers) can be simultaneously immersed and processed. Throughput can be increased and time and cost costs can be reduced. In addition, the silicon substrate that is the material of the flow path substrate is a thick substrate before processing, and is fixed to the support substrate 60 and ground to a desired thickness during processing. Breakage during handling can be prevented more effectively. Moreover, since standard goods can also be used, member cost can be suppressed.

Embodiment 3 FIG.
FIG. 9 is an external view of a droplet discharge apparatus using the droplet discharge head manufactured in the above embodiment. FIG. 10 is a diagram showing an example of main constituent means of the droplet discharge device. 9 and 10 is intended for printing by a droplet discharge method (inkjet method). Further, it is a so-called serial type device. In FIG. 12, a drum 101 that supports a print paper 110 that is a substrate to be printed and a droplet discharge head 102 that discharges ink to the print paper 110 and performs recording are mainly configured. Although not shown, there is an ink supply means for supplying ink to the droplet discharge head 102. The print paper 110 is held by being pressed against the drum 101 by a paper press roller 103 provided parallel to the axial direction of the drum 101. A feed screw 104 is provided parallel to the axial direction of the drum 101, and the droplet discharge head 102 is held. As the feed screw 104 rotates, the droplet discharge head 102 moves in the axial direction of the drum 101.

  On the other hand, the drum 101 is rotationally driven by a motor 106 via a belt 105 or the like. Further, the print control unit 107 drives the feed screw 104 and the motor 106 based on the print data and the control signal, and although not shown here, drives the oscillation drive circuit to vibrate the diaphragm 4, Printing is performed on the print paper 110 while controlling.

  Here, the liquid is ejected onto the print paper 110 as ink, but the liquid ejected from the droplet ejection head is not limited to ink. For example, in an application to be discharged onto a substrate to be a color filter, a light emitting element is used in an application to be discharged onto a substrate of a display panel (OLED or the like) using an electroluminescent element such as a liquid containing a color filter pigment or an organic compound For example, a liquid containing a compound and a liquid containing a conductive metal may be discharged from a droplet discharge head provided in each device. In addition, when the droplet discharge head is used as a dispenser and is used for discharging onto a substrate that is a microarray of biomolecules, DNA (Deoxyribo Nucleic Acids: deoxyribonucleic acid), other nucleic acids (for example, Ribo Nucleic Acid: ribonucleic acid, Peptide (Nucleic Acids: peptide nucleic acids, etc.) A liquid containing a probe such as a protein may be discharged. In addition, it can also be used for discharging dyes such as cloth.

2 is an exploded view of a droplet discharge head according to Embodiment 1. FIG. It is a longitudinal cross-sectional view of a droplet discharge head. It is a cross-sectional view of a droplet discharge head. FIG. 5 is a diagram illustrating a manufacturing process (part 1) of the flow path substrate 2 according to the first embodiment. FIG. 6 is a diagram illustrating a manufacturing process (No. 2) of the flow path substrate 2 according to the first embodiment. It is a figure showing the adhesion | attachment of the silicon substrate 51 and the support substrate 60, and a peeling process. FIG. 10 is a diagram illustrating a manufacturing process (No. 1) of the flow path substrate 2 of the second embodiment. FIG. 12 is a diagram illustrating a manufacturing process (No. 2) of the flow path substrate 2 of the second embodiment. It is an external view of a droplet discharge device using a droplet discharge head. It is a figure showing an example of the main structural means of a droplet discharge apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cover plate, 11 Resin thin film, 2 Flow path board | substrate, 21 Nozzle, 21a 1st nozzle, 21b 2nd nozzle, 22 Reservoir, 22a Reservoir recessed part, 23 Supply port, 24 Liquid protective film, 3 Cavity substrate, 31 Discharge chamber, 31a discharge chamber first recess, 31b discharge chamber second recess, 32 diaphragm, 33 liquid supply hole, 33a, 33b, 33c through hole, 34 insulating film, 35 common electrode terminal, 4 electrode substrate, 41 recess, 41a gap, 42 Individual electrode, 42a Electrode portion, 42b Lead portion, 42c Terminal portion, 43 Sealant, 51 Silicon substrate, 52, 53 Etching mask, 54 Recessed portion, 60 Support substrate, 61 UV curable adhesive layer, 62 Double-sided tape, 63 Roller, 64 vacuum suction jig, 71 silicon substrate, 72, 74 etching mask, 73 dry oxide film, 75 TEOS film 100 printer, 101 drum, 102 droplet discharge head, 103 paper press roller, 104 a feed screw, 105 belt, 106 motor, 107 print control means 110 print paper.

Claims (12)

A cavity substrate having a plurality of first recesses to be a part of a discharge chamber provided with a diaphragm for pressurizing liquid;
The first concave portion and the discharge chamber are formed by bonding with the cavity substrate, and the bottom surface has a plurality of supply ports that are communicated with the discharge chambers and penetrated so that the axis is perpendicular to the substrate. The second recess that is a part of the reservoir for accumulating the liquid supplied to the discharge chambers and the discharge chambers are formed so as to penetrate the axis perpendicular to the substrate, and are pressurized by the diaphragm A flow path substrate having a plurality of nozzles that discharge the liquid as droplets;
A droplet discharge head, comprising: a cover plate that covers an opening of the second recess.   2. The liquid according to claim 1, wherein the nozzle having a stepped shape or a tapered shape is formed so that a diameter of the nozzle becomes smaller from a contact surface side with the cavity substrate toward a liquid droplet ejection side. Drop ejection head.   3. The liquid droplet ejection head according to claim 1, wherein the flow path substrate has a plurality of third recesses that are a part of the ejection chamber on a side in contact with the cavity substrate.   The droplet discharge head according to claim 1, wherein the cover plate is a frame, and a flexible film is provided in the frame.   The droplet discharge head according to claim 1, wherein the flow path substrate is made of single crystal silicon.   The droplet discharge head according to claim 1, wherein the cover plate is made of SUS.   7. The liquid droplet ejection head according to claim 6, wherein the flexible film is made of polyphenylene sulfide.   A droplet discharge apparatus comprising the droplet discharge head according to claim 1. Forming and processing a concave portion to be a part of a reservoir for storing liquid to be supplied to a plurality of discharge chambers provided with a vibration plate for pressurizing liquid into a single crystal silicon substrate by wet etching,
A supply port provided on the bottom surface of the recess for communicating between each discharge chamber and the reservoir and each nozzle communicating with each discharge chamber and discharging pressurized liquid as droplets are formed on the substrate by dry etching. A manufacturing method of a droplet discharge head, characterized by processing to produce a flow path substrate.   10. The method according to claim 9, further comprising a step of covering the opening of the recess with a cover plate so that a cover plate made of a frame provided with a flexible film in the frame becomes a part of the reservoir. A method for manufacturing the liquid droplet ejection head as described.   2. The method according to claim 1, further comprising a step of fixing the substrate to be the flow path substrate to a support substrate and performing grinding or polishing until a desired thickness is achieved during or after the formation process in the production of the flow path substrate. A method for manufacturing a droplet discharge head according to 9 or 10. A method for manufacturing a droplet discharge device, wherein the droplet discharge device is manufactured by applying the method for manufacturing a droplet discharge head according to any one of claims 9 to 11.

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