JP2008044203A - Method for manufacturing liquid droplet delivering head, and liquid droplet delivering head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a liquid droplet delivering head capable of performing sealing while the concentration of a compound in a gap is held, and preventing a nozzle substrate from cracking when it is stuck, and to provide the liquid droplet delivering head. <P>SOLUTION: The method for manufacturing the liquid droplet delivering head includes a process for performing a first sealing for sealing end parts of respective recessed parts 9 becoming a delivering room 5, a process for performing a gas phase processing in the gap G through a gas phase processing line common to respective recessed parts (gas phase processing channel 12 and a second sealing hole 31) for communicating respective recessed parts 9 to the outside, and a process for performing a second sealing for sealing the gas phase processing line. The gas phase processing line is formed on an electrode glass substrate 2 so that the gas phase processing line is communicated with the outside on the opposite side face of the connecting face of the electrode glass substrate 2 with a cavity substrate 1, and the second sealing is performed at a part communicating to the outside. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a droplet discharge head that discharges a liquid material and a method for manufacturing a droplet discharge device. Here, the “liquid material” refers to a material having a viscosity that can be discharged from a nozzle, regardless of whether the material is aqueous or oily. It is sufficient if it has fluidity (viscosity) that can be discharged from the nozzle, and even if a solid substance is mixed, it may be a fluid as a whole.

As a droplet discharge head for discharging droplets, for example, there is an inkjet head provided with an electrostatic actuator. The ink jet head is formed as a vibration plate whose bottom surface of an ink chamber communicating with an ink nozzle can be elastically deformed. A substrate is disposed opposite to the diaphragm at a constant interval. A counter electrode is disposed on each of the diaphragm and the substrate, and a space between the counter electrodes is sealed. When a voltage is applied between the opposing electrodes, the bottom surface (vibrating plate) of the ink chamber is vibrated by electrostatic attraction or electrostatic repulsion toward the substrate by electrostatic force generated between them. Ink droplets are ejected from the ink nozzles due to fluctuations in the internal pressure of the ink chamber that occur with the vibration of the bottom surface of the ink chamber. By controlling the voltage applied between the counter electrodes, ink droplets are ejected only when necessary for recording.
Here, when the driving of the ink jet head is repeated by repeatedly applying a voltage between the counter electrodes, a phenomenon in which the electrostatic attraction characteristic or the electrostatic repulsion characteristic deteriorates is observed. In order to avoid such an adverse effect, it is conceivable to hydrophobize the actuator surface.

  Therefore, it is necessary to hermetically seal the gap in order to prevent the diaphragm from sticking to the electrode during ink jet driving. Conventionally, after sealing individual electrodes (referred to as first sealing), gas phase processing (dehydration processing and hydrophobic processing) in the gap is performed, and the gas processing line is sealed (second sealing). Airtight sealing is performed according to the procedure called. At this time, the second sealing is performed by depositing, for example, an epoxy-based adhesive in a sealing hole provided in the cavity substrate (see, for example, Patent Document 1). According to this method, the concentration of the compound for hydrophobic treatment in the gap can be kept high by performing sealing in two stages. That is, after performing the first sealing which has a relatively large sealing area and takes time, the gas phase treatment in the gap is performed, and then the second sealing is performed in which sealing can be performed at one place of the sealing hole. The time from the hydrophobic treatment to the completion of sealing can be shortened, and the concentration of the compound in the gap can be prevented from lowering.

Japanese Patent Laid-Open No. 11-2630124

  However, in the above prior art, the epoxy-based adhesive used in the first sealing and the second sealing leaks from the desired sealing position and rides on the cavity substrate, and may break when the nozzle substrate is bonded. It was.

  Accordingly, an object of the present invention is to provide a method for manufacturing a droplet discharge head and a droplet discharge head that can be sealed while maintaining the concentration of the compound in the gap and can prevent cracking when the nozzle substrate is bonded. To do.

The method for manufacturing a droplet discharge head according to the present invention includes a first substrate on which a plurality of recesses constituting a discharge chamber having a bottom wall as a vibration plate is formed, and a gap bonded to the vibration plate. A second substrate formed with a plurality of individual electrodes opposed to each other through the substrate and a surface of the first substrate opposite to the surface where the second substrate is bonded to form a nozzle hole A method of manufacturing a droplet discharge head having a third substrate formed, wherein a step of performing a first sealing that seals an end of each recess serving as a discharge chamber, and communicating each recess with the outside A step of performing a gas phase treatment in the gap via a ventilation line common to each recess, and a step of performing a second sealing for sealing the ventilation line, the ventilation line being connected to the first substrate of the second substrate. It is formed on the second substrate so as to communicate with the outside on the surface opposite to the bonding surface with the substrate, and communicates with the outside. Min at and performs second sealing.
As described above, since the second sealing is performed on the surface of the second substrate opposite to the bonding surface with the third substrate, the sealing material used for the second sealing is the bonding surface with the third substrate. Without cracking on the side, it is possible to prevent cracking when the third substrate is bonded.

In the method of manufacturing a droplet discharge head according to the present invention, the ventilation line is connected to the gas phase processing groove and the gas phase processing groove that connect the recesses so as to communicate with each other, and penetrates through the second substrate. It consists of holes.
In this way, a ventilation line can be formed on the second substrate.

In the method for manufacturing a droplet discharge head according to the present invention, the through hole is opened immediately before the second sealing is performed.
Thereby, it can prevent that a chemical | medical solution penetrate | invades in a gap from a through-hole.

In the method for manufacturing a droplet discharge head according to the present invention, the first sealing is performed by depositing a sealing material on the end of each recess.
As described above, since the first sealing is performed by film formation, it is possible to prevent the sealing material from running on the bonding surface side of the first substrate with the third substrate as in the case of using an adhesive. The crack at the time of board | substrate joining of a 3rd board | substrate can be prevented.

In the method for manufacturing a droplet discharge head according to the present invention, the sealing material is an inorganic material.
By using such an inorganic material, it is possible to form a sealed portion having high insulation and hermetic sealing ability and having resistance to acidic and alkaline solutions used for cleaning and the like.

The droplet discharge head according to the present invention includes a first substrate on which a plurality of recesses constituting a discharge chamber having a bottom wall as a vibration plate is formed, and the first substrate, the gap being formed in the vibration plate. A second substrate formed with a plurality of individual electrodes disposed opposite to each other and a surface of the first substrate opposite to the surface where the second substrate is bonded to form a nozzle hole. A droplet discharge head having a third substrate and a step of performing a first sealing for sealing the end of each recess serving as a discharge chamber, and a common for each recess that communicates each recess with the outside A step of performing a gas phase treatment in the gap through the ventilation line and a step of performing a second sealing for sealing the ventilation line, and joining the ventilation line to the first substrate of the second substrate; The second substrate is formed so as to communicate with the outside on the surface opposite to the surface, and the second seal is formed at the portion communicating with the outside. Those produced by the production method of the droplet discharge head for.
Thereby, it is possible to obtain a liquid droplet ejection head excellent in durability in which the vibration plate does not stick to the electrode.

  Hereinafter, a droplet discharge head manufactured by the manufacturing method of the present invention will be described. Here, as an example of a droplet discharge head, a face discharge type inkjet head that discharges ink droplets from ink nozzles provided on the surface of a nozzle substrate will be described with reference to FIGS. 1 and 2. Further, the present invention is not limited to the structure and shape shown in the following drawings, and can also be applied to an edge discharge type inkjet head that discharges ink droplets from ink nozzles provided at an end of a substrate. It is.

FIG. 1 is an exploded view of an ink jet head according to an embodiment of the present invention.
The ink jet head according to the present embodiment has a three-layer structure in which a cavity substrate 1 as a first substrate, an electrode glass substrate 2 as a second substrate, and a nozzle substrate 3 as a third substrate are stacked. ing.

  The cavity substrate 1 is composed of, for example, a (110) plane Si single crystal substrate (hereinafter simply referred to as a Si substrate) having a thickness of about 50 μm. By performing anisotropic wet etching on the Si substrate, a discharge chamber 5 whose bottom wall becomes the vibration plate 4 and a reservoir 6 for storing liquid discharged in common to each nozzle are formed. Further, electrode terminals 7 are formed on the cavity substrate 1 and connected to an oscillation circuit 17 shown in FIG. Here, an insulating film 8 is formed on the lower surface of the cavity substrate 1 (the surface facing the electrode glass substrate 2). In this example, the insulating film 8 is formed by a plasma CVD (Chemical Vapor Deposition) method using a TEOS (Tetraethylorthosilicate Silicate: Tetraethoxysilane, ethyl silicate) film of 0.1 μm. This is to prevent breakdown of the insulating film and short circuit when the inkjet head is driven.

The diaphragm 4 is composed of a high concentration boron doped layer. This boron doped layer is formed by doping boron at a high concentration (about 5 × 10 ₁₉ atoms / cm ₃ or more). For example, when single crystal silicon is etched with an alkaline aqueous solution, the etching rate becomes extremely slow. This is a so-called etching stop layer. The boron doped layer functions as an etching stop layer, whereby the thickness of the diaphragm 4 and the volume of the discharge chamber 5 can be formed with high accuracy.

  The electrode glass substrate 2 has a thickness of about 1 mm and is bonded to the lower surface of the cavity substrate 1 when viewed in FIG. Here, a borosilicate heat-resistant hard glass is used as the glass to be the electrode glass substrate 2. The electrode glass substrate 2 is provided with a recess 9 having a depth of about 0.2 μm at a position facing each discharge chamber 5 formed in the cavity substrate 1.

  The recess 9 is formed to extend to the end of the electrode glass substrate 2, and a lead portion 10 a and a terminal portion 10 b extending from the individual electrode 10 are formed on the bottom surface of the recess 9 (hereinafter referred to as individual The electrode 10, the lead portion 10a, and the terminal portion 10b are collectively referred to as an electrode portion).

  In the present embodiment, transparent ITO (Indium Tin Oxide) doped with tin oxide as an impurity is used as the material of the electrode portion formed on the bottom surface of the recess 9. A film is formed using a sputtering method to a thickness of 5 mm. At that time, as will be described later, an ITO pattern 11 that becomes a contact (hereinafter referred to as an equipotential contact) for making the individual electrode 10 and the silicon substrate bonded to the electrode glass substrate 2 equipotential is formed simultaneously with the individual electrode 10. Keep a film.

  Further, a gap G is formed between the insulating film 8 and the individual electrode 10 as shown in FIG. 2 described later. This gap G is determined by the depth of the recess 9 and the thickness of the electrode portion. It will be. Here, the material of the electrode part is not limited to ITO, and a metal such as chromium may be used as the material. However, in this embodiment, since it is transparent, it is easy to confirm whether or not the discharge has occurred. For this reason, ITO is used.

  The electrode glass substrate 2 is formed with a vapor processing groove 12 that connects the recesses 9 so as to communicate with each other with a depth of about 0.2 μm, which is the same as that of the recesses 9. The gas-phase treatment groove 12 is used for performing a hydrophobic treatment after removing moisture in the gap G, and will be described in detail later. The electrode glass substrate 2 is provided with an ink supply port 13 communicating with the reservoir 6.

  The nozzle substrate 3 is made of, for example, a silicon substrate having a thickness of about 180 μm, and nozzle holes 14 communicating with the discharge chamber 5 are formed. In addition, an orifice 15 for communicating the discharge chamber 5 and the reservoir 6 is formed on the lower surface of the nozzle substrate 3 in FIG. 1 (the surface on the bonding side bonded to the cavity substrate 1). In addition, diaphragms 16 are formed at both ends of the nozzle substrate 3 so as to face the reservoir 6 formed on the cavity substrate 1 and suppress pressure fluctuations in the reservoir 6.

  2 is a diagram showing a schematic configuration of the right half of the inkjet head of FIG. 1, FIG. 2 (a) is a sectional view of a portion obtained by cleaving the discharge chamber 5 in the longitudinal direction, and FIG. 2 (b) is an equipotential contact. It is sectional drawing of a part.

  The electrode terminal 7 of the cavity substrate 1 is connected to the oscillation circuit 17 via an FPC (Flexible Print Circuit) (not shown). Further, a through hole 21 is formed in a portion of the cavity substrate 1 corresponding to the terminal portion 10b, and the terminal portion 10b is connected to the oscillation circuit 17 from the through hole 21 via an FPC (not shown). It has become. The oscillation circuit 17 controls the supply and stop of charge to the individual electrode 10 through the terminal portion 10b. The oscillation circuit 17 oscillates at 24 kHz, for example, and supplies electric charges by applying pulse potentials of 0 V and 30 V to the individual electrodes 10. When the oscillation circuit 17 is driven in this way and charges are supplied to the individual electrodes 10 to be positively charged, the diaphragm 4 is negatively charged and is attracted to the individual electrodes 10 by an electrostatic force and bends. As a result, the volume of the discharge chamber 5 increases. When the charge supply to the individual electrode 10 is stopped, the diaphragm 4 returns to its original state. At this time, since the volume of the discharge chamber 5 also returns to the original, the ink of the difference is discharged by the pressure, and printing is performed, for example, by landing on the recording paper to be recorded. Then, when the vibration plate 4 is bent downward again, ink is supplied from the reservoir 6 into the discharge chamber 5 through the orifice 15. Further, ink is supplied to the ink jet head through an ink supply port 13 formed on the electrode glass substrate 2. Thus, the electrostatic actuator is mainly constituted by the diaphragm 4 and the individual electrode 10. Such a method is called pulling, but there is also a method called pushing that discharges droplets using a spring or the like.

  Further, a sealing portion 18 is formed at the end of the gap G, and sealing is performed in units of individual electrodes 10. The sealing portion 18 is formed by depositing a sealing material through a through hole 21 formed in the cavity substrate 1 by a method such as CVD (Chemical Vapor Deposition), sputtering, or vapor deposition. Is formed. In this example, an inorganic sealing material is deposited by deposition.

  In this example, after the end of each recess 9 is sealed (referred to as first sealing), the gas phase treatment (dehydration treatment and hydrophobic treatment) in the gap G is performed, and the gas phase treatment is performed. The gas-phase treatment line (corresponding to a ventilation line that communicates the recess 9 with the outside) for sealing is sealed (referred to as second sealing) in two stages. This is because the concentration of the compound for the hydrophobic treatment in the gap G is kept high as described in the conventional description. By this gas phase treatment (hydrophobic treatment), a hydrophobic film 22 made of hexamethyldisilazane (HMDS) is formed on the surface of the insulating film 8 and the surface of the individual electrode 10.

  Further, as shown in FIG. 2B, the electrode glass substrate 2 has an equipotential between the individual electrode 10 and the cavity substrate 1 when the electrode glass substrate 2 and the cavity substrate 1 are anodically bonded. Are equipotential contacts. About the part used as an equipotential contact, when forming the recessed part 9 in the glass substrate 2, it leaves without etching. Then, ITO 0.1 μm, which is conductive, is formed together with the individual electrode 10 thereon to form an ITO pattern 11. Therefore, the equipotential contact protrudes by 0.1 μm from the surface of the electrode glass substrate 2 by the amount of the ITO pattern 11. On the other hand, in the cavity substrate 1, a portion of the TEOS film (0.1 μm) corresponding to the equipotential contact is removed, and a window exposing the Si substrate (boron doped layer) which is the main material of the cavity substrate 1 is formed. By contacting the Si substrate and the ITO pattern 11 through this window, the equipotential between the individual electrode 10 electrically connected to the ITO pattern 11 and the Si substrate is ensured at the time of anodic bonding.

FIG. 3 is a view of the electrode glass substrate as viewed from above, and particularly shows a state after the first sealing and the second sealing. Usually, the droplet discharge heads are made in units of wafers, and finally separated into each droplet discharge head (head chip).
In FIG. 3, the air opening hole 30 communicates the recess 9 with the outside, and is for preventing the gap G from being sealed during anodic bonding. For example, the inside of the gap G is prevented from being pressurized by the generation of a gas such as oxygen due to heating to each substrate during anodic bonding or the like. The air opening hole 30 is formed by a sandblasting method, a cutting process, or the like.

  In this example, as described above, in order to perform the gas phase processing (dehydration processing and hydrophobic processing) in the gap G, the gas phase processing line is sealed (second sealing) after the gas phase processing. 3 indicates a second sealing hole that forms a gas phase processing line together with the gas phase processing groove 12. The second sealing hole 31 communicates with the gas phase processing groove 12 and is formed through the electrode glass substrate 2.

  The dicing line 40 is a line for separating a plurality of droplet discharge heads integrally formed on the wafer. Accordingly, the portions on the right side and the upper side of the dicing line 40 in FIG. 3 do not remain in the completed droplet discharge head. That is, the air opening hole 30 and the second sealing hole 31 do not remain in the completed inkjet head.

Next, a method for manufacturing the ink jet head will be described with reference to FIGS. 4 to 5b. The physical quantities such as specific numerical values shown below are merely examples, and are not limited thereto.
FIG. 4 is a diagram illustrating a manufacturing method of an electrode glass substrate, and FIGS. 5A and 5B are diagrams illustrating manufacturing processes of the inkjet head following FIG. In FIG. 5a, (a) to (d) show cross sections at the equipotential contact portion of the electrode glass substrate, and (e) and thereafter and FIG. 6 show cross sections at the individual electrode portions of the electrode glass substrate.

First, the manufacturing method of an electrode glass substrate is demonstrated with reference to FIG.
(A) A Cr film 101 serving as an etching mask is formed on one surface of a glass substrate 100 of about 1 mm to a thickness of 0.1 μm.
(B) A resist 102 is applied to the surface of the formed Cr film 101, and resist patterning for forming the recess 9 is performed.
(C) The Cr film 101 is patterned by etching with a cerium ammonium nitrate aqueous solution using the resist 102 as a mask.
(D) The glass substrate 100 is immersed in an aqueous ammonium fluoride solution with the resist 102 attached, and the recess 9 is formed by etching by 0.2 μm. The portion that becomes the equipotential contact is left without being etched. Here, the shape of the equipotential contact is not limited as long as the electrode portion and the Si substrate can be brought into contact with each other to be equipotential.
(E) The resist 102 is stripped, and then the Cr film 101 is stripped.

(F) An electrode member 103 having a thickness of 0.1 μm is formed on the entire surface of the patterning surface by using, for example, a sputtering method. In this example, ITO is used as the electrode member.
(G) A resist 104 is applied to the patterning surface, and resist patterning is performed so that the ITO film remains in the recess 9 and the equipotential contact portion.
(H) Then, unnecessary portions of the ITO film 103 are removed using the resist 104 as a mask, and electrode portions are formed in the recesses 9. Then, the resist 104 is peeled off.
(I) The ink supply port 13 and the air opening hole 30 are formed by the sand blasting method or the cutting process and penetrated. Similarly, the second sealing hole 31 is excavated by sandblasting or cutting, but stops when the remaining thickness reaches about 10 μm without being penetrated. Note that all the recesses 9 for the individual electrodes 10 and the recesses for the equipotential contacts are connected at one end as shown in FIG. 2 and communicated with the air opening hole 30 penetrating the glass substrate 100.
Thus, the electrode glass substrate 2 is created.

Next, a manufacturing method until completion of the inkjet head will be described.
5a and 5b are diagrams illustrating the manufacturing process of the inkjet head subsequent to FIG. 4b.

(A) An electrode glass substrate 2 processed by the manufacturing method shown in FIG. 4 is prepared.
(B) One side of the Si substrate 200 having a plane orientation of (110) and a low oxygen concentration is mirror-polished to produce a substrate having a thickness of 220 μm. Next, the surface on which the boron doped layer 301 of the Si substrate 200 is formed is set on a quartz boat so as to face a solid diffusion source mainly composed of B ₂ O ₃ . A quartz boat is set in a vertical furnace, the inside of the furnace is put into a nitrogen atmosphere, the temperature is raised to 1050 ° C., the temperature is kept as it is for 7 hours, and boron is diffused into the Si substrate 200 to form a boron doped layer 201.
In the boron doping process, it is preferable that the input temperature of the Si substrate 200 is 800 ° C., and the extraction temperature of the Si substrate 200 is also 800 ° C. Accordingly, it is possible to quickly pass through a region (600 ° C. to 800 ° C.) where the growth rate of oxygen defects is high, so that the generation of oxygen defects can be suppressed. Further, although a boron compound is formed on the surface of the boron doped layer 201 (not shown), etching with a hydrofluoric acid aqueous solution is possible by oxidizing for 1 hour 30 minutes in an oxygen and water vapor atmosphere at 600 ° C. It can be chemically changed to B ₂ O ₃ + SiO ₂ . B ₂ O ₃ + SiO ₂ is removed by etching with a hydrofluoric acid aqueous solution in a state where it is chemically changed to B ₂ O ₃ + SiO ₂ .
Thereafter, an insulating film (TEOS insulating film) 8 is formed on the surface on which the boron doped layer 201 is formed by plasma CVD, the processing temperature at the time of film formation is 360 ° C., the high frequency output is 250 W, the pressure is 66.7 Pa (0.5 Torr), A film having a gas flow rate of 0.1 μm is formed under the conditions of a TEOS flow rate of 100 cm ₃ / min (100 sccm) and an oxygen flow rate of 1000 cm ₃ / min (1000 sccm).
Next, a resist is applied to the surface of the formed TEOS insulating film 8, resist patterning is performed to open the window portion 8a with which the equipotential contact 33 contacts at the time of anodic bonding, and etching is performed with a hydrofluoric acid aqueous solution. Is patterned. Then, the resist is peeled off.

(C) After heating the Si substrate 200 and the electrode glass substrate 2 on which the electrode pattern has been formed to 360 ° C., a negative electrode is connected to the electrode glass substrate 2 and a positive electrode is connected to the Si substrate 200, and a voltage of 800 V is applied to perform anodic bonding. To do.
At the time of anodic bonding, the glass is electrochemically decomposed at the interface between the Si substrate 200 and the electrode glass substrate 2 to generate oxygen. In some cases, gas adsorbed on the surface is generated by heating. However, since these gases escape from the air opening hole 30, the gap G does not become positive pressure.
At this time, the ITO film 103 and the Si substrate 200 come into contact with each other at an equipotential contact, and the ITO film 103 and the Si substrate 200 become equipotential. Therefore, no discharge occurs in the gap G during anodic bonding.

(D) After anodic bonding, the surface of the Si substrate 200 is ground until the thickness of the Si substrate 200 is about 60 μm. Thereafter, in order to remove the work-affected layer, the Si substrate 200 is etched by about 10 μm with a potassium hydroxide solution having a concentration of 32 w%. As a result, the thickness of the Si substrate 200 becomes about 50 μm.
In the grinding step and the work-affected layer removal step, the air release hole 30 is protected by using a single-sided protective jig, tape, or the like so that liquid does not enter the gap G from the air release hole 30. Since the second sealing hole 31 does not penetrate, the liquid does not enter the gap G from the second sealing hole 31.
(E) Plasma CVD is used on the entire etching surface, the processing temperature during film formation is 360 ° C., the high frequency output is 700 W, the pressure is 33.3 Pa (0.25 Torr), and the gas flow rate is TEOS flow rate 100 cm ₃ / min (100 sccm). ), A TEOS etching mask 202 is formed to a thickness of 1.0 μm under the condition of an oxygen flow rate of 1000 cm ₃ / min (1000 sccm).

(F) An epoxy adhesive is poured into the air opening hole 30 to seal the hole. As a result, the gap G is hermetically sealed, and liquid does not enter from the atmosphere opening hole 30 in the subsequent processes.
This step is preferably performed after the TEOS etching mask 202 is formed. If the air opening hole 30 is sealed before the film formation, the gas in the confined gap G is thermally expanded during the film formation, pushing up the thinned Si substrate 200 and breaking the Si substrate 200.
Next, resist patterning is applied to the TEOS etching mask 202, and etching is performed with a hydrofluoric acid aqueous solution, and the portion 202a corresponding to the discharge chamber 5 is patterned. Then, the resist is peeled off.
(G) Further, resist patterning is applied to the TEOS etching mask 202, and etching is performed with a hydrofluoric acid solution by 0.7 μm, and the portion 202b corresponding to the reservoir 6 and the portion 202c corresponding to the through hole 21 are patterned. The remainder of the TEOS etching mask of the portion 202b corresponding to the reservoir 6 and the portion 202c corresponding to the through hole 21 is 0.3 μm. This is because the reservoir and the through hole are finally thickened to increase the rigidity. Then, the resist is peeled off.
At this time, as in JP-A-2004-306444, patterning may be performed so that an Si island remains in the through hole.

(H) The bonded substrate is immersed in an aqueous 35 wt% potassium hydroxide solution until the thickness of the recess that becomes the discharge chamber 5 becomes about 5 μm. At this time, the etching of the portion that becomes the reservoir 6 and the portion that becomes the through hole 21 has not yet started.
(I) Then, in order to remove the TEOS etching mask 202 in the portion 202b corresponding to the reservoir 6 and the portion 202c corresponding to the through hole 21, the bonded substrate is immersed in a hydrofluoric acid aqueous solution and removed.
(J) The bonded substrate is immersed in an aqueous potassium hydroxide solution having a concentration of 3 wt% for about 20 minutes to stop etching due to a decrease in the etching rate in the boron dope layer 301. Thereby, the discharge chamber 5 is formed. By performing etching using the two types of potassium hydroxide aqueous solutions having different concentrations, the surface roughness of the diaphragm 4 can be suppressed, and the thickness accuracy can be reduced to 0.80 ± 0.05 μm or less. The discharge performance can be stabilized.
Note that the depths of the recesses 200a and 200b at the portions to be the reservoir 6 and the through hole 21 are about 30 μm. Accordingly, the thicknesses of the recesses 200a and 200b at the portions to be the reservoir 6 and the through hole 21 are about 20 μm.

  By leaving the thickness in this way, the strength is improved, the reservoir portion and the through hole portion are not broken during Si etching, and the yield can be improved. That is, since the reservoir portion and the through-hole portion have a larger area than the diaphragm portion, a thin film having the same thickness as the diaphragm 4 remains when the bottom portion is thinned by silicon etching. In other words, the rigidity is very weak, and it may break due to mechanical vibrations or a force pushed up by a foreign matter sandwiched in the gap between the electrodes. Therefore, by using a structure having a thickness of about 20 μm as in this embodiment, it is not broken in the process of thinning, and the yield can be improved.

(K) When the Si etching is completed, the bonded substrate is immersed in a hydrofluoric acid aqueous solution, and the TEOS etching mask 202 on the surface of the Si substrate 200 is peeled off.
(L) In order to remove the Si thin film remaining in the through hole, a Si mask is attached to the surface of the Si substrate 200, RF power 200W, pressure 40Pa (0.3 Torr), CF ₄ flow rate 30 cm ₃ / min (30 sccm) Under these conditions, RIE dry etching is performed for 1 hour, plasma is applied only to the through hole portion, and the through hole 21 is formed. At this time, the gap G is opened to the atmosphere.
Further, the ink supply port 13 is formed by performing laser processing from the hole portion serving as the ink supply port 13 of the electrode glass substrate 2 and penetrating the bottom of the reservoir portion of the silicon Si substrate 200.

(M) An Si mask opened so that the sealing material is deposited on the end of the lead portion 10a (the end of each recess 9) is attached to the surface of the Si substrate. Here, a TEOS film is used as the sealing material. Then, using plasma CVD, the processing temperature during film formation is 360 ° C., the high frequency output is 700 W, the pressure is 33.3 Pa (0.25 Torr), the gas flow rate is TEOS flow rate 100 cm ₃ / min (100 sccm), and the oxygen flow rate is 1000 cm. _A TEOS film is formed to a thickness of 3.0 μm under the condition of ₃ / min (1000 sccm) to form the sealing portion 18. As described above, since the first sealing is performed by depositing and depositing the sealing material, the first sealing can be performed without the sealing material riding on the cavity substrate 1.

(N) The glass remaining in the second sealing hole 31 is removed by dry etching or laser processing, and the second sealing hole 31 is penetrated.
(O) After the bonding substrate is placed in a vacuum chamber, it is exposed to a nitrogen atmosphere to remove moisture in the gap G. Thereafter, the bonding substrate is exposed to an HMDS gas atmosphere. As a result, the HMDS gas is filled into the gap G through the gas phase processing line (the second sealing hole 31 and the gas phase processing groove 12). And the gap | interval G will be in a sealing state again by inject | pouring the sealing material (epoxy-type resin) 31a into the 2nd sealing hole 31, and making it harden | cure.
In this way, the second sealing hole 31 is provided in the electrode glass substrate 2, and the sealing material 31 a is injected into the second sealing hole 31 from the surface opposite to the bonding surface of the cavity substrate 1 to be sealed. Therefore, the gap G can be hermetically sealed (second sealing) without the sealing material 31a riding on the cavity substrate 1.
(P) The nozzle substrate 3 is bonded to the surface of the cavity substrate 1 with an epoxy adhesive.
(Q) Dicing is performed along the dicing line 40 and cut into individual heads. At this time, the electrode part (refer to FIG. 3) that is short-circuited at the time of anodic bonding is divided for each recess 9. Further, the air release hole 30 and the second sealing hole 31 are also separated from the head.
Thus, the ink jet head shown in FIG. 1 is completed.

As described above, according to the manufacturing method of the ink jet head of the present embodiment, the second sealing hole 31 is provided in the electrode glass substrate 2 and the second sealing is performed from the surface opposite to the bonding surface of the cavity substrate 1. Since the sealing material 31a is injected into the blind hole 31 and sealed, the sealing material 31a does not run on the cavity substrate 1 and can be prevented from cracking when the nozzle substrate is bonded.
That is, a vapor phase treatment line for communicating each recess 9 to the outside is provided in the electrode glass substrate 2, and the vapor phase treatment line communicates with the outside on the surface opposite to the bonding surface of the electrode glass substrate 2 with the cavity substrate 1. In this way, by performing the second sealing at the portion communicating with the outside, it is possible to reliably prevent the inconvenience that the sealing material 31a rides on the cavity substrate 1.

  In addition, since the second sealing hole 31 is not penetrated in advance and is opened immediately before the second sealing is performed, the chemical solution does not enter the gap G from the second sealing hole 31 and the yield is increased. Can be improved.

  Further, since the sealing is performed in two stages of the first sealing and the second sealing, the concentration of the compound for the hydrophobic treatment in the gap G can be kept high, and the individual electrode 10 of the diaphragm 4 can be maintained. An ink jet head having excellent durability with no sticking to the surface can be obtained.

  Moreover, since the method of forming each part such as the discharge chamber 5 after joining the Si substrate 200 and the electrode glass substrate 2 is used, the handling of the substrate becomes easy, so that the cracking of the substrate can be reduced. In addition, it is possible to increase the diameter of the substrate. If the diameter can be increased, a large number of inkjet heads can be taken out from a single substrate, so that productivity can be improved.

  In the above embodiment, the method for manufacturing an ink jet head has 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. For example, by changing the liquid material discharged from the nozzle hole 14, in addition to the ink jet printer, the production of a color filter for a liquid crystal display, the formation of a light emitting part of an organic EL display device, the biomolecular solution used for genetic testing, It can be used as a droplet discharge device for various applications such as microarray production.

1 is an exploded perspective view of an inkjet head according to an embodiment of the present invention. The figure which shows schematic structure of the inkjet head of the right half of FIG. The figure which looked at the electrode glass substrate from the upper surface. The figure which shows the manufacturing method of an electrode glass substrate. Sectional drawing (1/2) which shows the manufacturing process of the inkjet head following FIG. Sectional drawing (2/2) which shows the manufacturing process of the inkjet head following FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cavity substrate, 2 Electrode glass substrate, 3 Nozzle substrate, 4 Diaphragm, 5 Discharge chamber, 10 Individual electrode, 12 Gas-phase process groove, 14 Nozzle hole, 18 Sealing part, 21 Through-hole, 22 Hydrophobized film, 31 Sealing hole, 31a Sealing material.

Claims (6)

A first substrate in which a plurality of recesses constituting a discharge chamber having a bottom wall as a vibration plate is formed, and a plurality of individual electrodes that are bonded to the first substrate and are opposed to the vibration plate via a gap. A second substrate formed by forming a nozzle hole and a third substrate bonded to a surface of the first substrate opposite to the surface bonded to the second substrate. A method for manufacturing a droplet discharge head comprising:
Performing a first sealing for sealing the end of each of the recesses serving as the discharge chamber;
Performing a gas phase treatment in the gap through a ventilation line common to the respective recesses to communicate the respective recesses to the outside;
Performing a second sealing for sealing the ventilation line,
The ventilation line is formed in the second substrate so as to communicate with the outside on a surface opposite to the bonding surface of the second substrate with the first substrate, and at the portion communicating with the outside, A method for manufacturing a droplet discharge head, wherein the second sealing is performed.   The vent line includes a gas-phase processing groove that connects the recesses to each other and a through-hole that communicates with the gas-phase processing groove and penetrates the second substrate. Item 2. A method for manufacturing a droplet discharge head according to Item 1.   3. The method of manufacturing a droplet discharge head according to claim 2, wherein the through hole is opened immediately before the second sealing is performed.   4. The droplet discharge head according to claim 1, wherein the first sealing is performed by depositing and depositing a sealing material on an end of each of the recesses. 5. Production method.   The method for manufacturing a droplet discharge head according to claim 4, wherein the sealing material is an inorganic material. A first substrate in which a plurality of recesses constituting a discharge chamber having a bottom wall as a vibration plate is formed, and a plurality of individual electrodes that are bonded to the first substrate and are opposed to the vibration plate via a gap. A second substrate formed by forming a nozzle hole and a third substrate bonded to a surface of the first substrate opposite to the surface bonded to the second substrate. A droplet discharge head comprising:
Performing a first sealing for sealing the end of each of the recesses serving as the discharge chamber;
Performing a gas phase treatment in the gap through a ventilation line common to the respective recesses to communicate the respective recesses to the outside;
Performing a second sealing for sealing the ventilation line,
The ventilation line is formed in the second substrate so as to communicate with the outside on a surface opposite to the bonding surface of the second substrate with the first substrate, and at the portion communicating with the outside, A droplet discharge head manufactured by a method for manufacturing a droplet discharge head for performing second sealing.

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