JP2009292122A - Nozzle substrate manufacturing method, droplet discharge head manufacturing method, and droplet discharge head - Google Patents

Abstract

[PROBLEMS] To provide a nozzle substrate manufacturing method that is free from edge damage or edge sag at the nozzle opening edge, resin residue inside the nozzle, and has a stable nozzle shape and high cleanliness inside the nozzle, and further improves ejection performance. And a droplet discharge head manufacturing method and a droplet discharge head that simultaneously improve productivity.
A support substrate 60 is formed on a surface on which a recess is formed, a step of forming a recess serving as a nozzle 11 from one surface side of a silicon substrate 100, a step of filling a tip 40 of the recess with resin 40, and a surface on which the recess is formed. The step of bonding, the step of thinning the silicon substrate from the surface opposite to the surface where the recesses are formed, and the step of peeling the support substrate from the thinned silicon substrate, and then removing the resin And a step of opening the nozzle.
[Selection] Figure 9

Description

  The present invention relates to a method for manufacturing a nozzle substrate for forming nozzles for discharging droplets of ink or the like, a method for manufacturing a droplet discharge head, and a droplet discharge head using the nozzle substrate.

  An ink jet recording apparatus, which is a typical example of a droplet discharge apparatus, includes an ink jet head. In general, an ink jet head includes a nozzle substrate on which a plurality of nozzles for ejecting ink droplets are formed, and a cavity substrate on which an ink flow path having an ejection chamber that is an ink pressure chamber is formed. The ink droplets are ejected from selected nozzles by joining (also referred to as a flow path substrate) and applying pressure to the ejection chamber by the driving unit. Actuator driving methods include a method using electrostatic force, a piezoelectric method using a piezoelectric element, and a method using a heating element.

  In recent years, there has been an increasing demand for high quality printing, image quality, etc. for inkjet heads. For this reason, the number of nozzle rows is increased, the number of nozzles per row is increased, and the number of nozzles is increased and lengthened. The density is increased and the discharge performance is improved. Against this background, various ideas and proposals have conventionally been made regarding the method of processing the nozzles of an inkjet head or the method of manufacturing a nozzle substrate.

In an ink jet head, in order to improve ink ejection characteristics, it is desirable to adjust the flow path resistance of the nozzle part and adjust the thickness of the substrate so that the optimum nozzle length is obtained. When manufacturing such a nozzle substrate, for example, as shown in Patent Document 1, anisotropic dry using ICP (Inductively Coupled Plasma) discharge from one surface (bonding surface with a cavity substrate) side of a silicon substrate. After the first nozzle hole and the second nozzle hole with different inner diameters are formed in two stages by etching, a part is dug down by anisotropic wet etching from the surface (discharge surface) opposite to the joint surface Thus, a method of adjusting the nozzle length has been adopted.
However, in this method, the ejection surface where the nozzle opens is on the bottom surface of the recess that is one step deep from the surface of the substrate, so that flying droplets of ink droplets occur, or paper dust, ink, etc. that cause nozzle clogging Has adhered to the bottom surface of the recess, which is the discharge surface, there is a problem that wiping work for wiping the bottom surface of the recess with a rubber piece or a felt piece becomes difficult in order to remove paper dust, ink and the like.

On the other hand, as shown in Patent Document 2, for example, the first nozzle hole and the second nozzle hole are formed by previously polishing the silicon substrate to a desired thickness and then performing dry etching on both sides of the silicon substrate. There is also a way to do it. However, in this method, as the density of the ink jet head increases, the thickness of the silicon substrate must be further reduced. However, such a substrate is liable to be broken during the manufacturing process and is expensive. Further, during dry etching, cooling is performed from the back surface of the substrate with He gas or the like so that the processing shape is stabilized. However, when the nozzle penetrates, the He gas may leak and etching may be impossible.
For this reason, a recess that becomes a nozzle, that is, a nozzle shape, is formed in advance on the silicon substrate. For example, the silicon substrate is thinned by grinding, etching, or the like after being bonded to a support substrate such as quartz glass using a resin. The method of opening the recessed part used as this was taken (for example, refer patent document 3). However, this method has a problem that the tip of the nozzle is chipped when the nozzle is opened because the inside of the concave portion serving as the nozzle is a space.

  In order to prevent chipping of the nozzle tip at the time of nozzle opening as described above, a method of filling the entire interior of the concave portion serving as a nozzle with a resin for bonding when the support substrate is bonded (for example, , See Patent Document 4).

Japanese Patent Laid-Open No. 11-28820 Japanese Patent Laid-Open No. 9-57981 JP 2006-159661 A JP 2006-315217 A

However, even in the method disclosed in Patent Document 4, a recess serving as a nozzle is opened, and after that, a SiO ₂ film is formed on the ejection surface, a water-repellent film is formed thereon, and then the resin in the nozzle is drawn out. At this time, there are problems such as edge damage such as burrs of the SiO ₂ film and edge sagging at the edge of the opening of the nozzle tip, and resin residue may remain.

  In view of the above-described problems of the prior art, the present invention is free from edge damage and edge sagging at the nozzle tip opening edge, and resin residue inside the nozzle, and has a high nozzle stability and nozzle cleanliness. An object of the present invention is to provide a method for manufacturing a droplet, and further to provide a method for manufacturing a droplet discharge head and a droplet discharge head that can simultaneously improve discharge performance and productivity by using such a nozzle substrate. For the purpose.

The method for manufacturing a nozzle substrate according to the present invention includes a step of forming a recess serving as a nozzle from one surface side of a silicon substrate, a step of filling a resin at the tip of the recess, and a surface on which the recess is formed. The step of laminating the support substrate, the step of thinning the silicon substrate until the resin is exposed from the surface opposite to the surface where the recess is formed, and peeling the support substrate from the thinned silicon substrate, And a step of opening the nozzle by removing the resin.
According to the present invention, since the resin is filled only in the tip part (bottom part of the recess) of the recess serving as the nozzle, the inside of the nozzle is protected by the resin even after the silicon substrate is thinned. The water repellent treatment of the ejection surface can be performed without affecting the above.
In addition, it is possible to prevent the intrusion of grinding fluid or abrasive during grinding or polishing for opening the nozzle (concave), maintaining high cleanliness inside the nozzle, and at the same time reducing the amount of resin filling to a relatively small amount. Therefore, the time required for removing the resin can be shortened, and there is no edge damage, edge sagging, and resin residue at the nozzle tip edge, and the stability of the nozzle shape can be improved.

In addition, in the method of manufacturing the nozzle substrate according to the present invention, in the step of forming the recess serving as the nozzle, the first nozzle hole communicates with the first recess serving as the first nozzle hole and the first nozzle hole. And forming a second recess serving as a second nozzle hole so that the cross-sectional area is larger than or gradually decreasing or reducing the cross-sectional area toward the first nozzle hole, and is formed at the tip of the first recess. It is filled with resin.
In this way, the recess that becomes the nozzle communicates with the first recess that becomes the first nozzle hole and the first nozzle hole, and the cross-sectional area is larger than the first nozzle hole or the cross-sectional area is the first. In the case of forming with the second recess serving as the second nozzle hole so as to be gradually reduced or reduced toward the first nozzle hole, the tip of the first recess is filled with resin, In addition to the effects described above, it is possible to improve the ejection performance such as improving the straightness of the ejected droplets.

Moreover, the manufacturing method of the nozzle board | substrate which concerns on this invention forms the recessed part used as a nozzle by anisotropic dry etching.
By forming the concave portion to be the nozzle by anisotropic dry etching, the nozzle can be formed perpendicular to the silicon substrate surface and with high shape accuracy.

In addition, the method for producing a nozzle substrate according to the present invention includes spin coating or spray coating of resin on the surface on which the concave portion serving as a nozzle is formed, and then performing O ₂ ashing to thereby apply a small amount of resin to the concave portion or the second coating. 1 is left at the tip of the recess.
In this way, when filling the resin, the resin is filled into the recess that becomes the nozzle by spin coating or spray coating, and then a small amount of resin remains at the tip of the recess or the first recess by O ₂ ashing. Adjust as follows. Thereby, it is possible to fill the resin without generating bubbles up to the tip of the recess serving as the nozzle, and it is possible to fill only the tip of the recess serving as the nozzle or the first recess.

The nozzle substrate manufacturing method according to the present invention includes a step of forming a water repellent film on the surface of the thinned silicon substrate after the silicon substrate is thinned, and a surface on which the water repellent film is formed. And a step of applying a protective tape.
Since the concave portion serving as the nozzle or the tip of the first concave portion is closed by the resin, the water-repellent film can be formed only on the ejection surface. Further, when removing the resin by O ₂ ashing, since the protective tape is stuck on the water repellent film, the water repellent film and the inner surface of the nozzle are not affected by the O ₂ plasma at all.

A method for manufacturing a droplet discharge head according to the present invention is a method for manufacturing a droplet discharge head by applying any one of the above-described nozzle substrate manufacturing methods.
According to the present invention, a nozzle substrate having high nozzle shape stability and high cleanliness inside the nozzle can be manufactured. By using this nozzle substrate, a droplet discharge head that simultaneously improves discharge performance and productivity. Can be manufactured.

A droplet discharge head according to the present invention is manufactured by the above-described method for manufacturing a droplet discharge head.
As a result, a droplet discharge head that can simultaneously improve discharge performance and improve productivity can be obtained.

  Hereinafter, a droplet discharge head according to an embodiment of the present invention will be described with reference to the drawings. 1 to 4 show a face discharge type ink jet head using an electrostatic drive system as an example of a droplet discharge head. FIG. 1 is an exploded perspective view showing an exploded schematic configuration of the ink jet head, and a part thereof is shown in cross section. 2 is a partial cross-sectional view of the ink jet head showing a schematic configuration of the right half of FIG. 1 showing the assembled state, FIG. 3 is an enlarged cross-sectional view showing the nozzle part of FIG. 2, and FIG. It is a top view.

  The inkjet head 10 of this embodiment is configured by bonding three substrates, a nozzle substrate 1, a cavity substrate 2, and an electrode substrate 3, in this order. The cavity substrate 2 and the electrode substrate 3 are bonded by anodic bonding, and the nozzle substrate 1 and the cavity substrate 2 are bonded using an adhesive such as an epoxy resin. In the present embodiment, the face discharge type inkjet head 10 is used, but an edge discharge type that discharges ink droplets from the end of the substrate can also be used. In this case, the nozzle substrate is bonded to the end surfaces of both the cavity substrate and the lid substrate that closes the ink flow path. In addition, the inkjet head 10 has a three-layer structure in which three substrates are stacked as shown in the figure, but uses a reservoir substrate in which a reservoir portion which is a common ink chamber is provided on a substrate different from the cavity substrate 4 4 A four-layer structure composed of a single substrate can also be used.

  The nozzle substrate 1 manufactured according to the present invention is applied to all structures regardless of the above-described ejection type, lamination type, or actuator driving method. The nozzle substrate 1 is made from a silicon substrate. In general, a single crystal silicon substrate is used, but a polycrystalline silicon (polysilicon) substrate may be used. When a polycrystalline silicon substrate is used, the same nozzle shape accuracy can be obtained, and the material cost can be reduced. The nozzle substrate 1 described below is mainly composed of single crystal silicon or polycrystalline silicon, and is simply referred to as “silicon substrate”. A method for manufacturing the nozzle substrate 1 will be described in detail later.

  A plurality of nozzles 11 for ejecting ink droplets are formed on the nozzle substrate 1. In the case of the present embodiment, each nozzle 11 has a first nozzle hole 11a having a small diameter (about 20 μm) located on the ink droplet ejection side and a second nozzle having a large diameter (about 50 μm) located on the ink supply side. The nozzle hole 11b is configured in two stages. The first nozzle hole 11a is formed in a cylindrical shape with a small diameter perpendicular to the surface (ink ejection surface) 1a of the nozzle substrate 1, and the second nozzle hole 11b is connected to the first nozzle hole 11a and the central axis. Are formed coaxially (concentrically) so as to coincide with each other with high accuracy, and the cross-sectional area is larger than that of the first nozzle hole 11a, and the cross-sectional shape is formed in a cylindrical shape. Thus, by making the nozzle 11 have a structure having two vertical holes, the ink droplet ejection direction can be aligned with the central axis direction of the nozzle 11 and stable ink ejection characteristics can be exhibited. That is, there is no variation in the flying direction of ink droplets, there is no scattering of ink droplets, and variations in the ejection amount of ink droplets can be suppressed. In addition, the nozzle density can be increased. The shape and structure of the nozzle 11 are not limited to those shown in FIG. For example, the shape of the second nozzle hole 11b is (a) tapered, (b) bell-shaped, (c) multi-stage shape so that the cross-sectional area gradually decreases or decreases toward the first nozzle hole 11a. It is good. Alternatively, (d) the nozzle substrate 1 may be provided with only the straight first nozzle hole 11a, and the second nozzle hole 11b may be provided on another substrate, for example, a reservoir substrate.

An appropriate protective film is formed on the nozzle substrate 1. That is, on the front and back surfaces of the nozzle substrate 1 and the inner surface of the nozzle 11, as shown in FIG. 3, an ink-resistant protective film (anti-discharge liquid protective film) 12 made of, for example, SiO ₂ is used so that silicon is not corroded by ink. Is formed. Further, on the ink-resistant surface 12a of the ink ejection surface 1a, in order to improve the water repellency on the ink ejection surface 1a, the entire surface of the ink ejection surface 1a is water-repellent with the edge of the ejection port of the nozzle 11 as a boundary. A film 13 is formed. The water repellent film 13 is preferably composed mainly of a fluorine-containing organosilicon compound. The reason is that the hydroxyl group on the surface of the ink-resistant protective film 12 is strongly bonded to the hydrolyzable group such as a methoxy group of the fluorine-containing organosilicon compound, so that the ink-resistant protective film 12 and the water-repellent film formed on the surface thereof. This is because the adhesiveness to 13 is improved.

  The cavity substrate 2 to which the nozzle substrate 1 configured as described above is bonded and bonded is manufactured from a single crystal silicon substrate. In the cavity substrate 2, ink channel grooves communicating with each of the nozzles 11 are formed by anisotropic wet etching. The ink flow path groove includes a discharge recess 210 serving as the discharge chamber 21 with the bottom wall serving as the diaphragm 22, a reservoir recess 230 serving as the reservoir 23 serving as a common ink chamber, and the reservoir recess 230 and each discharge recess 210. An orifice recess 240 is formed which becomes the communicating orifice 24. The diaphragm 22 can be formed with a high accuracy by forming it with a boron diffusion layer having the same thickness. The orifice 24 can also be provided on the nozzle substrate 1 side, and in this case, a narrow groove-like recess communicating the reservoir recess 230 and each ejection recess 210 with the joint surface 100b (the surface opposite to the ink ejection surface 100a). Formed as.

In addition, an insulating film 25 for preventing a short circuit, a dielectric breakdown, or the like is formed on the cavity substrate 2 over the entire bonding surface with the electrode substrate 3. As the insulating film 25, SiO ₂ or SiN, or a so-called High-k material such as Al ₂ O ₃ or HfO ₂ is used according to the purpose. In particular, when a high-k material is used, the relative dielectric constant is larger than that of SiO ₂ , so that the pressure generated by the actuator can be increased, and the density can be further increased. The insulating film 25 may be formed on the opposing surface of the individual electrode 31 as necessary. Further, an ink-resistant protective film 26 made of SiO ₂ as a hydrophilic film is formed on the entire surface of the cavity substrate 2 on the ink channel groove side by a thermal oxidation method, a sputtering method, a CVD method, or the like, and further made of a metal film such as Pt. A common electrode 27 is formed on the cavity substrate 2.

  The electrode substrate 3 that is anodically bonded to the cavity substrate 2 is made of, for example, a borosilicate glass substrate. Recesses 32 are formed by etching on the glass substrate at positions facing the vibration plate 22, and individual electrodes 31 generally made of ITO (Indium Tin Oxide) are formed on the bottom surface of each recess 32 by sputtering. Is done. An ink supply port 33 communicating with the reservoir 23 for supplying ink is formed by a sandblast method or the like. The ink supply port 33 is connected to an ink tank (not shown).

The electrode substrate 3 and the cavity substrate 2 are anodically bonded so that the individual electrode 31 and the diaphragm 22 are disposed to face each other with a predetermined gap (space) 34 (for example, 0.1 μm). Thus, the electrostatic actuator 4 that can apply a required pressure to the discharge chamber 21 is configured by the individual electrode 31 and the diaphragm 22 having the insulating film 25 facing each other via the gap 34. Note that a sealing portion 35 is provided at the external communication portion of the gap 34 in order to hermetically seal so that moisture and dust do not enter the inside. As this sealing technique, there are a method of applying an epoxy resin or the like, or a method of depositing or forming an inorganic oxide or the like by a sputtering method, and any method may be used. Thereby, the drive durability and reliability of the electrostatic actuator 4 are improved.
2 and 4, in order to drive the electrostatic actuator 4, an FPC (Flexible Print Circuit) on which a driving means 5 such as a driver IC is mounted is electrically connected in an electrode extraction unit 36. A wiring is connected to the terminal portion 31a of each individual electrode 31 and the metal common electrode 27 provided on the cavity substrate 2 by the adhesive. The inkjet head 10 is completed as described above.

Here, the operation of the inkjet head 10 will be described. In order to eject ink droplets from an arbitrary nozzle 11, the electrostatic actuator 4 corresponding to the nozzle 11 is driven as follows.
A pulse voltage is applied between the individual electrode 31 and the diaphragm 22 which is a common electrode by the driving means 5. The diaphragm 22 is attracted and brought into contact with the individual electrode 31 side by the electrostatic force generated by the application of the pulse voltage, generates a negative pressure in the discharge chamber 21, sucks ink in the reservoir 23, and vibrates the ink (meniscus). Vibration). When the voltage is released when the vibration of the ink becomes substantially maximum, the vibration plate 22 is detached from the individual electrode 31, and the ink is pushed out from the nozzle 11 by the restoring force of the vibration plate 22 at that time. Discharge.

  Next, an example of the manufacturing method of the nozzle substrate 1 of this embodiment is demonstrated using FIGS. 5 to 9 are partial cross-sectional views showing the manufacturing process of the nozzle substrate 1, and a part of a plurality of silicon wafers produced on the silicon wafer is shown in cross-section. In addition, the numerical values of the substrate thickness, film thickness, etching depth, temperature, pressure, and the like described below are just examples, and are not limited thereto.

(A) First, a silicon substrate 100 having a thickness of 525 μm is prepared, and this silicon substrate 100 is set in a thermal oxidation apparatus, and is thermally oxidized under conditions of an oxidation temperature of 1075 ° C., an oxidation time of 4 hours, and a mixed atmosphere of oxygen and water vapor. Then, a 1 μm thick SiO ₂ film 101 is uniformly formed on the surface of the silicon substrate 100 (FIG. 5A).
(B) Next, a resist 102 is coated on a bonding surface (referred to as a surface bonded to the cavity substrate 2) 100b of the silicon substrate 100, and a portion 110b to be the second nozzle hole 11b is patterned (FIG. 5B). )).
(C) The silicon substrate 100 is half-etched with, for example, a buffered hydrofluoric acid aqueous solution (hydrofluoric acid aqueous solution: ammonium fluoride aqueous solution = 1: 6) to thin the SiO ₂ film 101. At this time, the SiO ₂ film 101 on the ink ejection surface 100a side is also etched, and the thickness of the SiO ₂ film 101 is reduced (FIG. 5C).
(D) The resist 102 on the silicon substrate 100 is removed by washing with sulfuric acid or the like (FIG. 5D).

(E) Again, the resist 103 is coated on the bonding surface 100b side patterned in (b) of the silicon substrate 100, and the portion 110a to be the first nozzle hole 11a is patterned (FIG. 6E).
(F) Then, the silicon substrate 100 is etched with a buffered hydrofluoric acid aqueous solution (hydrofluoric acid aqueous solution: ammonium fluoride aqueous solution = 1: 6) to open the SiO ₂ film 101 of the portion 110a to be the first nozzle hole 11a. At this time, the SiO ₂ film 101 on the ink ejection surface 110a side is etched and completely removed (FIG. 6F).
(G) The resist 103 provided on the bonding surface 100b side of the silicon substrate 100 is removed by washing with sulfuric acid or the like (FIG. 6G).

(H) Next, with an ICP (Inductively Coupled Plasma) dry etching apparatus, the opening of the SiO ₂ film 101 is anisotropically dry etched vertically to a depth of 25 μm, for example, to form the first nozzle hole 11a. 1 recess 11A is formed (FIG. 7H). In this case, C ₄ F ₈ and SF ₆ are used as the etching gas, and these etching gases may be used alternately. Here, C ₄ F ₈ is used to protect the side surface of the hole so that the etching of the side surface of the hole to be formed does not proceed, and SF ₆ is used to promote the vertical etching of the hole.
(I) Next, half etching is performed with a buffered hydrofluoric acid solution so that only the SiO ₂ film 101 in the portion 110b to be the second nozzle hole 11b is removed (FIG. 7 (i)).
(J) The opening of the SiO ₂ film 101 is again anisotropically dry etched to a depth of 40 μm, for example, by an ICP dry etching apparatus again to form the second recess 11B that becomes the second nozzle hole 11b. (FIG. 7 (j)).

(K) Then, the SiO ₂ film 101 remaining on the surface of the silicon substrate 100 is entirely removed with a hydrofluoric acid aqueous solution, and then the silicon substrate 100 is set in a thermal oxidation apparatus, an oxidation temperature of 1000 ° C., an oxidation time of 2 hours, and in an oxygen atmosphere. Ink-resistant protection is performed on the side and bottom surfaces of the first recess 11A and the second recess 11B processed by the ICP dry etching apparatus, the bonding surface 100b of the silicon substrate 100, and the ink discharge surface 100a. The SiO ₂ film 12a to be the film 12 is uniformly formed with a film thickness of 0.1 μm (FIG. 7 (k)).

(L) Next, the silicon substrate 100 is placed on a glass turntable (not shown) with the bonding surface 100b facing up, and for example, a thermosetting acrylic resin 40 is formed with a film thickness of 1 Spin coat at 5 μm. Thereby, the acrylic resin 40 enters and fills the inside of the first recess 11A and the second recess 11B (FIG. 8L). Thereafter, the resin 40 is cured by heating. The resin 40 injected into the first and second recesses 11A and 11B is not limited to an acrylic resin. Any one-component resin may be used, and urethane-based, epoxy-based, and the like can also be used. Further, the injection method is not limited to the spin coating method, and may be a spray coating method. According to the spin coating method or the spray coating method, a thermosetting resin or a UV curable resin is completely filled up to the tip of the first recess 11A (the bottom surface of the first recess 11A) without generating bubbles. be able to.

(M) Next, O ₂ ashing is performed in vacuum so that a small amount of the resin 40 remains in the first recess 11A or only at the tip thereof (FIG. 8 (m)). The O ₂ ashing conditions at this time are RF: 300 W, oxygen gas flow rate: 30 ml / min, and ashing time: 15 minutes. Note that the resin 40 may remain in the bottom corners of the second recess 11B.
(N) Next, a double-sided adhesive tape 50 having an adhesive layer on both sides, such as a dicing tape, for example, is attached to a support substrate 120 made of a transparent material such as glass. Then, the support substrate 120 and the silicon substrate 100 are bonded together (FIG. 8 (n)).

(O) Then, grinding is performed with a back grinder from the ink ejection surface 100a side of the silicon substrate 100, and the silicon substrate 100 is thinned until the tip of the first recess 11A is opened (FIG. 8 (o)). Furthermore, the tip of the first recess 11A may be opened by polishing the ink discharge surface 100a with a polisher or a CMP (Chemical Mechanical Polishing) device. Alternatively, the opening at the tip of the first recess 11A may be performed by dry etching. For example, by dry etching using SF ₆ as an etching gas, the silicon substrate 100 is thinned to the tip of the first recess 11A, and the SiO ₂ film 12a at the tip of the first recess 11A exposed on the surface is CF _4. Alternatively, it may be removed by dry etching using CHF ₃ or the like as an etching gas. In view of the necessity of a water rinsing removal process for the abrasive in the nozzle after CMP processing, it is desirable to open the openings by dry etching.
At this time, the resin 40 basically remains exposed in the opening of the first concave portion 11A, so that water, a grinding fluid, and an abrasive do not easily enter inside during grinding or polishing. Furthermore, the presence of the resin 40 makes the opening of the first recess 11A continuous with the ink ejection surface 100a, and edge damage or edge sag due to grinding or polishing unevenness is less likely to occur.

(P) A SiO ₂ film 12b to be an ink resistant protective film 12 is formed with a thickness of 0.1 μm on the ink discharge surface 100a of the thinned silicon substrate 100 by a sputtering apparatus. Here, the formation of the SiO ₂ film 12a is not limited to the sputtering method as long as it can be performed at a temperature (about 200 ° C.) or less at which the resin 40 does not deteriorate. However, in consideration of ink resistance and the like, it is necessary to form a dense film, and it is desirable to use an apparatus capable of forming a dense film at room temperature, such as an ECR (Electron Cyclotron Resonance) sputtering apparatus.
Subsequently, a water repellent treatment (ink repellent treatment) is performed on the surface of the silicon substrate 100 on the ink ejection surface 100a side. A water repellent (ink repellent) material containing F atoms is formed by vapor deposition or dipping to form a water repellent film 13 (FIG. 9 (p)). At this time, a resin 40 is filled in the tip of the opened first recess 11A, and the resin 40 protects the inside of the first recess 11A and the second recess 11B as a so-called blind plug. The SiO ₂ film 12b and the water repellent film 13 are not formed on the surface of the resin 40. Accordingly, the surface on the ink discharge surface 100a side of the silicon substrate 100 with the opening edge of the first recess 11A, that is, the edge of the discharge port of the first nozzle hole 11a formed by removing the resin 40 described later as a boundary. A water repellent film 13 can be formed on the entire surface.

(Q) Ultraviolet rays are irradiated from the support substrate 120 side, the double-sided adhesive tape 50 and the support substrate 120 are peeled off, and then the double-sided adhesive tape 50 is slowly peeled off from the silicon substrate 100 (FIG. 9 (q)).

(R) Next, for example, a protective tape 60 of E-MASK (registered trademark: manufactured by Nitto Denko) is attached on the water repellent film 13 formed on the ink ejection surface 100a side of the silicon substrate 100, and then plasma is applied. It is set in a source dry etching apparatus, O ₂ plasma treatment is performed from the bonding surface 100b side of the silicon substrate 100 opposite to the protective tape 60, and the resin 40 remaining at the tip of the first recess 11A is completely removed. (FIG. 9 (r)). At this time, since the water-repellent film 13 on the ink ejection surface 100a side is protected by the protective tape 60, it is not affected by O ₂ plasma at all.
Even if a part of the resin 40 remains in the corner of the second recess 11B as shown in FIG. 9 (q), the resin 40 is also completely removed by the O ₂ plasma treatment. be able to. Thereby, the shape accuracy of the first nozzle hole 11a and the second nozzle hole 11b, the cleanliness inside the nozzle 11 and the stability of the nozzle shape can be kept high.

(S) Finally, if the protective tape 60 is slowly peeled off from the silicon substrate 100, the nozzle substrate 1 is completed (FIG. 9 (s)).

According to the manufacturing method of the nozzle substrate 1 according to the present embodiment, when opening the first recess 11A to be the first nozzle hole 11a in the thinning process of the silicon substrate 100, the tip portion of the first recess 11A. Since the resin 40 is filled in the nozzle, chipping at the nozzle tip can be eliminated. Furthermore, since the inside of the nozzle 11 is protected by filling the tip 40 of the first recess 11A with the resin 40, only the ink discharge surface 100a is bounded by the tip opening edge of the first nozzle hole 11a. Water repellent treatment is possible. In addition, it is possible to prevent the intrusion of the grinding fluid or the abrasive during the grinding or polishing performed for opening the first recess 11A, and the cleanliness inside the nozzle 11 can be improved. Since it can be limited to a relatively small amount only inside 11A, the time required for resin removal can be shortened, plasma damage to the ink ejection surface 100a can be reduced, and the resin residue can be eliminated, thereby improving productivity. Further, during the grinding and polishing, since the resin 40 is present in the first recess 11A, the opening of the first recess 11A is a surface continuous with the ink discharge surface 100a, and an edge caused by uneven grinding or polishing. Damage or edge sag is less likely to occur.
Therefore, it is possible to simultaneously improve the cleanliness in the nozzle 11 and the stability of the nozzle shape.

  Next, a method of manufacturing the inkjet head 10 using the nozzle substrate 1 manufactured as described above will be described with reference to FIGS. 10 to 12 are partial cross-sectional views showing a process of manufacturing the cavity substrate 2 from the silicon substrate 200 after the silicon substrate 200 is bonded onto the electrode substrate 3 manufactured in advance.

(A) First, a recess 32 is formed in a glass substrate 300 made of borosilicate glass or the like by etching with hydrofluoric acid using an etching mask of gold / chrome. Note that the recess 32 has a groove shape slightly larger than the shape of the individual electrode 31, and a plurality of the recesses 32 are formed for each individual electrode 31. Then, an individual electrode 31 made of ITO (Indium Tin Oxide) is formed inside the recess 32 by, for example, sputtering. Then, the electrode substrate 3 is manufactured by forming the hole 33a to be the ink supply hole 33 by sandblasting or the like (FIG. 10A).

(B) Next, a silicon substrate 200 in which, for example, a boron diffusion layer 201 having a thickness of 0.8 μm is formed on the entire surface of one surface of a single crystal silicon substrate (hereinafter referred to as a silicon substrate) 200 having a thickness of 280 μm, for example. Then, on the surface (lower surface) of the boron diffusion layer 201 of the silicon substrate 200, a SiO ₂ film is formed as a whole with a film thickness of 0.1 μm as the insulating film 9 by a thermal oxidation method (FIG. 10A). .
(C) The silicon substrate 200 and the electrode substrate 3 fabricated as shown in FIG. 10A are heated to 360 ° C., and the silicon substrate 200 is connected to the anode and the electrode substrate 3 is connected to the cathode, so that the voltage is about 800V. A voltage is applied to perform anodic bonding (FIG. 10C).
(D) The entire surface of the bonded silicon substrate 200 is polished to reduce the thickness to, for example, about 50 μm (FIG. 10D), and the entire surface of the silicon substrate 200 is light-etched by wet etching. Remove processing marks.

(E) Next, a TEOS film 260 which is a SiO ₂ film using TEOS (Tetraethoxysilane) as a source gas is formed by plasma CVD on the surface of the bonded silicon substrate 200 processed into a thin plate. Then, the TEOS film 260 is patterned with a resist for forming the recess 210 serving as the discharge chamber 21, the groove 240 serving as the orifice 24, and the recess 230 serving as the reservoir 23, and the TEOS film 260 in these portions is removed by etching. .
Thereafter, the silicon substrate 200 is anisotropically wet-etched with a potassium hydroxide aqueous solution, thereby forming a recess 210 serving as the discharge chamber 21, a groove 240 serving as the orifice 24, and a recess 230 serving as the reservoir 23 (FIG. 11E). ). At this time, the portion that becomes the electrode lead-out portion 36 for wiring is also etched and thinned. In the wet etching step, for example, a 35% by weight potassium hydroxide aqueous solution can be used first, and then a 3% by weight potassium hydroxide aqueous solution can be used. At this time, since etching is stopped on the surface of the boron diffusion layer 201, the thickness of the diaphragm 22 can be formed with high accuracy and surface roughness can be prevented.

(F) After the etching of the silicon substrate 200 is completed, etching is performed with a hydrofluoric acid aqueous solution to remove the SiO ₂ film 260 formed on the upper surface of the silicon substrate 200 (FIG. 11F).

(G) A TEOS film serving as an ink-resistant protective film is formed by plasma CVD on the surface of the silicon substrate 200 where the recesses 210 and the like serving as the discharge chambers 21 are formed (FIG. 11G).

(H) The electrode extraction part 29 is opened by RIE (Reactive Ion Etching) or the like. In addition, laser processing or microblast processing is performed on the hole portion that becomes the ink supply port 33 of the electrode substrate 3 to penetrate the bottom portion of the concave portion 230 that becomes the reservoir 23 of the silicon substrate 200, thereby forming the ink supply port 33. In addition, a sealing portion 35 that hermetically seals with a sealing material such as an epoxy resin is provided in the external communication portion of the gap 34 between the diaphragm 22 and the individual electrode 31. Further, the common electrode 27 is formed on the end portion of the silicon substrate 200 by sputtering (FIG. 11H).

The cavity substrate 2 is manufactured from the silicon substrate 200 bonded to the electrode substrate 3 through the above steps.
Finally, the nozzle substrate 1 manufactured as described above is bonded onto the cavity substrate 2 by adhesion and cut into individual head chips by dicing, whereby the inkjet head 10 shown in FIG. 2 is completed. (FIG. 12).

According to the method for manufacturing the ink jet head 10 according to the present embodiment, since the nozzle substrate 1 manufactured as described above is provided, the ink jet head 10 that simultaneously achieves improvement in ejection performance and productivity can be obtained.
Further, since the cavity substrate 2 is produced from the silicon substrate 200 in a state of being bonded to the electrode substrate 3 produced in advance, the silicon substrate 200 is supported by the electrode substrate 3 and cracks even if the silicon substrate 200 is thinned. It is easy to handle without any damage. Accordingly, the yield is improved as compared with the case where the cavity substrate 2 is manufactured alone.

  In the above embodiment, the nozzle substrate, the inkjet head, and the manufacturing method thereof have been described. However, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the idea of the present invention. it can. For example, the actuator driving method is not limited to the electrostatic driving method, and the present invention can also be applied to a driving method using a piezoelectric element or a heating element. Further, by changing the liquid material discharged from the nozzle, in addition to the inkjet printer 400 shown in FIG. 13, a living body used for manufacturing a color filter of a liquid crystal display, forming a light emitting portion of an organic EL display device, genetic testing, etc. It can be used as a droplet discharge device for various uses such as manufacturing a microarray of a molecular solution. By mounting the nozzle substrate manufactured by the nozzle substrate manufacturing method of the present embodiment on a droplet discharge head (inkjet head) and a droplet discharge device, the droplet discharge head has both excellent discharge characteristics and durability. In addition, a droplet discharge device can be obtained.

1 is an exploded perspective view showing a schematic configuration of an ink jet head according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view of an inkjet head showing a schematic configuration of a right half of FIG. The expanded sectional view of the nozzle hole part of FIG. FIG. 3 is a top view of the ink jet head of FIG. 2. The fragmentary sectional view which shows the manufacturing process of a nozzle substrate. FIG. 6 is a partial cross-sectional view illustrating a nozzle substrate manufacturing process following FIG. 5. FIG. 7 is a partial cross-sectional view illustrating a nozzle substrate manufacturing process following FIG. 6. FIG. 8 is a partial cross-sectional view illustrating a nozzle substrate manufacturing process following FIG. 7. FIG. 9 is a partial cross-sectional view illustrating a nozzle substrate manufacturing process following FIG. 8. The fragmentary sectional view which shows the manufacturing process of an inkjet head. FIG. 11 is a partial cross-sectional view illustrating the manufacturing process of the inkjet head following FIG. 10. FIG. 12 is a partial cross-sectional view illustrating the manufacturing process of the inkjet head following FIG. 11. 1 is a perspective view of an ink jet printer using an ink jet head according to an embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Nozzle board | substrate, 2 cavity board | substrate, 3 electrode board | substrate, 4 electrostatic actuator, 5 drive means, 10 inkjet head, 11 nozzle, 11a 1st nozzle hole, 11b 2nd nozzle hole, 11A 1st recessed part, 11B 1st 2 recesses, 12 ink resistant protective film, 13 water repellent film, 21 discharge chamber, 22 diaphragm, 23 reservoir, 24 orifice, 25 insulating film, 26 ink resistant protective film, 27 common electrode, 31 individual electrode, 32 recessed part, 33 Ink supply port, 34 Gap, 35 Sealing part, 36 Electrode extraction part, 40 Resin, 50 Double-sided adhesive tape, 100 Silicon substrate, 104 Resin, 400 Inkjet printer.

Claims (7)

Forming a recess to be a nozzle from one surface side of the silicon substrate;
Filling the resin into the tip of the recess;
Bonding the support substrate to the surface on which the recesses are formed;
Thinning the silicon substrate until the resin is exposed from the surface opposite to the surface on which the concave portion is formed;
Peeling the support substrate from the thinned silicon substrate and then opening the nozzle by removing the resin;
A method for manufacturing a nozzle substrate, comprising:   In the step of forming the concave portion to be the nozzle, the first concave portion to be the first nozzle hole and the first nozzle hole communicate with and have a cross-sectional area larger than that of the first nozzle hole, or A second recess serving as a second nozzle hole is formed so that the area gradually decreases or decreases toward the first nozzle hole, and the resin is filled in the tip of the first recess. The method of manufacturing a nozzle substrate according to claim 1.   The method for manufacturing a nozzle substrate according to claim 1, wherein the concave portion to be the nozzle is formed by anisotropic dry etching. The resin is spin-coated or spray-coated on the surface where the concave portion to be the nozzle is formed, and then O ₂ ashing is performed to leave a small amount of resin at the tip of the concave portion or the first concave portion. The method for manufacturing a nozzle substrate according to any one of claims 1 to 3. Forming a water repellent film on the surface of the thinned silicon substrate after thinning the silicon substrate;
Attaching a protective tape to the surface on which the water-repellent film is formed;
5. The method of manufacturing a nozzle substrate according to claim 1, comprising:   A method for manufacturing a droplet discharge head, wherein the method for manufacturing a nozzle substrate according to any one of claims 1 to 5 is applied to manufacture a droplet discharge head.   A droplet discharge head manufactured by the method for manufacturing a droplet discharge head according to claim 6.

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