JP2007021839A - Liquid droplet delivering head, its manufacturing method and liquid droplet delivering apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid droplet delivering head or the like capable of surely and easily performing an electric connection between a common electrode and a diaphragm when a polycrystalline silicon or the like is used for forming highly precisely the diaphragm. <P>SOLUTION: The liquid droplet delivering head is equipped with a silicon substrate 1a, an etching protective film 17 formed on one surface of the silicon substrate 1a, and a thin silicon film 12 formed on the etching protective film 17 and constituting a part of the diaphragm 10 driven by electrostatic force. The etching protective film 17 has an opening part 18, and the thin silicon film 12 is formed also on the opening part 18, and is brought into contact with the silicon substrate 1a at the opening part 18 to be electrically conducted with the silicon substrate 1a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a droplet discharge head, a manufacturing method thereof, and a droplet discharge device, and in particular, when a diaphragm is formed of polycrystalline silicon or the like, the electrical connection between the common electrode and the diaphragm is reliably performed. The present invention relates to a droplet discharge head capable of forming a droplet, a manufacturing method thereof, and a droplet discharge apparatus equipped with the droplet discharge head.

  In recent years, inkjet heads (droplet discharge heads) mounted on inkjet printers and the like have been increased in number of nozzles in order to support high-speed printing, and actuator parts (vibration plates, individual electrodes, etc.) have been demanded for higher resolution. The drive unit is required to be miniaturized. When the actuator part is miniaturized and densified, the partition wall partitioning the discharge chambers for storing droplets becomes thin, and the rigidity of the partition wall decreases. Further, when the rigidity of the partition wall that partitions the discharge chamber is lowered, there is a problem that vibration is transmitted to the adjacent discharge chamber when the diaphragm forming the bottom wall of the discharge chamber is driven, and so-called crosstalk occurs. .

  In order to suppress the occurrence of such crosstalk, there is a method of lowering the height of the partition wall that partitions the discharge chamber, but a silicon substrate on which a recess or the like serving as the discharge chamber is formed in order to reduce the height of the partition wall If the thickness is reduced, handling becomes difficult and the yield is extremely reduced.

  In the conventional inkjet head manufacturing method for such a problem, the silicon substrate to be the cavity substrate and the electrode glass substrate on which the individual electrodes are formed are joined, then the silicon substrate is thinned, and then the recess to be the discharge chamber Etc. are formed to prevent a decrease in yield and to increase the rigidity of the partition walls to suppress the occurrence of crosstalk (see, for example, Patent Document 1).

  On the other hand, when the density of the actuator portion is increased, high processing accuracy is required with respect to the thickness of the partition wall that partitions the discharge chamber and the thickness of the diaphragm. In a conventional inkjet head manufacturing method, a layer in which boron is diffused at a high concentration is formed on one surface of a silicon substrate, and this is used as an etching stop layer to form a diaphragm (see, for example, Patent Document 2). However, in the process of diffusing boron at a high concentration, the boron concentration distribution may not be uniform due to process variations and the like, and as a result, the thickness of the diaphragm may vary.

For this reason, in a conventional method for manufacturing a droplet discharge head, a diaphragm is formed by forming a polycrystalline silicon thin film while controlling the film thickness by a film formation method such as sputtering (for example, Patent Documents). 3). Further, in this method of manufacturing a droplet discharge head, the generation of crystal defects in the silicon substrate that greatly affects the processing accuracy of the partition walls partitioning the discharge chamber is suppressed by forming a diaphragm made of a polycrystalline silicon thin film at a low temperature. It was like that.
Japanese Patent Laid-Open No. 11-993 (pages 3 to 4, FIGS. 3 and 4) JP-A-6-71882 (pages 10 to 12, FIG. 17) JP 2004-195904 A (page 7, FIG. 4)

  However, in the conventional method for manufacturing a droplet discharge head (see, for example, Patent Document 3), a silicon oxide film that is resistant to an alkaline etching solution such as potassium hydroxide is used when a diaphragm made of a polycrystalline silicon thin film is formed. A silicon nitride film or the like has been used as an etching protective film. Since a silicon oxide film or a silicon nitride film used as an etching protective film also functions as an insulating film, how to make an electrical connection for applying a voltage to the diaphragm has been a problem.

  The present invention relates to a droplet discharge head capable of reliably and easily performing electrical connection between a common electrode and a diaphragm when polycrystalline silicon or the like is used to form a diaphragm with high accuracy, and a manufacturing method thereof. It is an object of the present invention to provide a method and a droplet discharge apparatus equipped with the droplet discharge head.

A droplet discharge head according to the present invention includes a silicon substrate, an etching protective film formed on one surface of the silicon substrate, and a part of a diaphragm formed on the etching protective film and driven by electrostatic force. The etching protective film has an opening, the silicon thin film is also formed in the opening, and is in electrical contact with the silicon substrate in contact with the silicon substrate in the opening. is there.
For example, an opening is formed in an etching protection film made of silicon oxide or silicon nitride, and a silicon substrate and a silicon thin film made of polycrystalline silicon or the like are in contact with the opening, so that a voltage is applied to the silicon thin film through the silicon substrate. It becomes possible to apply.
In addition, for example, a polycrystalline silicon or pseudo single crystal silicon can be formed by an ECR (Electron Cyclotron Resonance) sputtering method or the like, whereby a silicon thin film and a diaphragm with high thickness accuracy can be formed.

In the droplet discharge head according to the present invention, a common electrode is formed on a silicon substrate, and a voltage is applied from the common electrode to the silicon thin film through the silicon substrate.
Since the silicon thin film is in contact with the silicon substrate at the opening of the etching protective film, a voltage can be applied to the silicon thin film from the common electrode formed on the silicon substrate.

The droplet discharge head according to the present invention includes a silicon substrate, an etching protection film formed on one surface of the silicon substrate, and a diaphragm formed on the etching protection film and driven by electrostatic force. The silicon thin film has a portion that does not overlap with the etching protective film, and a common electrode is formed in a portion of the silicon thin film that does not overlap with the etching protective film. Is applied with a voltage.
A silicon thin film made of polycrystalline silicon or the like has a portion that does not overlap with an etching protective film made of silicon oxide, silicon nitride or the like, and a voltage is applied to the silicon thin film directly by applying a voltage from a common electrode formed in this portion. Can be applied with a voltage.
In addition, for example, a polycrystalline silicon or pseudo single crystal silicon can be formed by an ECR (Electron Cyclotron Resonance) sputtering method or the like, whereby a silicon thin film and a diaphragm with high thickness accuracy can be formed.

A droplet discharge head according to the present invention includes an electrode substrate bonded to a silicon substrate on which a common electrode is formed, and an individual electrode that is formed on the electrode substrate and drives a vibration plate. The individual electrode has an electrode extraction portion connected to the drive circuit, and the common electrode is provided adjacent to the electrode extraction portion.
Since the common electrode is provided adjacent to the electrode take-out portion where the individual electrode is connected to the drive circuit, mounting on the droplet discharge device is facilitated.

The droplet discharge head according to the present invention has an insulating film formed on a silicon thin film.
By forming the insulating film on the silicon thin film, it is possible to prevent the silicon thin film and the individual electrodes from coming into contact with each other to cause a short circuit or breakdown.

In the droplet discharge head according to the present invention, the silicon thin film is formed of polycrystalline silicon or pseudo single crystal silicon.
By forming polycrystalline silicon or pseudo-single-crystal silicon by an ECR (Electron Cyclotron Resonance) sputtering method or the like, a silicon thin film and a diaphragm with high thickness accuracy can be formed.

In the droplet discharge head according to the present invention, the etching protective film is formed of silicon oxide or silicon nitride.
By forming the etching protective film from silicon oxide or silicon nitride, it is possible to easily form an etching protective film highly resistant to an alkaline etching solution such as an aqueous potassium hydroxide solution.

The method for manufacturing a droplet discharge head according to the present invention includes a step of forming an etching protective film on one surface of a silicon substrate, a step of forming an opening in the etching protective film, and an etching protective film on and in the opening. And a step of forming a silicon thin film that constitutes a part of the diaphragm driven by electrostatic force.
By forming an opening in the etching protection film on the silicon substrate and forming a silicon thin film on the etching protection film and in the opening, it is possible to apply a voltage to the silicon thin film through the silicon substrate.
In addition, for example, a polycrystalline silicon or pseudo single crystal silicon can be formed by an ECR (Electron Cyclotron Resonance) sputtering method or the like, whereby a silicon thin film and a diaphragm with high thickness accuracy can be formed.

The method for manufacturing a droplet discharge head according to the present invention includes a step of forming an insulating film on the silicon thin film and a step of etching the silicon substrate on which the insulating film is formed after the step of forming the silicon thin film. It is.
By forming the insulating film on the silicon thin film, it is possible to prevent the silicon thin film and the individual electrodes from coming into contact with each other to cause a short circuit or breakdown.
Further, by etching the silicon substrate on which the insulating film is formed, a recess or the like serving as a discharge chamber can be formed.

The method for manufacturing a droplet discharge head according to the present invention includes a step of forming an etching protective film on one surface of a silicon substrate, and a part of a diaphragm driven by electrostatic force is formed on the etching protective film. Forming a silicon thin film, etching the silicon substrate so that a part of the etching protective film is exposed, and removing the exposed portion of the etching protective film so that the silicon thin film does not overlap the etching protective film. And a step of forming a common electrode in a portion of the silicon thin film that does not overlap the etching protective film.
Since the etching protection film is exposed by etching the silicon substrate and the etching protection film in that portion is removed to form a common electrode in contact with the silicon thin film, a voltage can be directly applied to the silicon thin film. .
In addition, for example, a polycrystalline silicon or pseudo single crystal silicon can be formed by an ECR (Electron Cyclotron Resonance) sputtering method or the like, whereby a silicon thin film and a diaphragm with high thickness accuracy can be formed.

The method for manufacturing a droplet discharge head according to the present invention includes a step of forming an insulating film on a silicon thin film before the step of etching the silicon substrate.
By forming the insulating film on the silicon thin film, it is possible to prevent the silicon thin film and the individual electrodes from coming into contact with each other to cause a short circuit or breakdown.

In the method of manufacturing a droplet discharge head according to the present invention, the silicon substrate on which the insulating film is formed is bonded to the electrode substrate on which the individual electrode for driving the vibration plate is formed before the step of etching the silicon substrate. The method includes a step of providing an electrode extraction portion where the individual electrode is connected to the drive circuit on the electrode substrate, and forming the common electrode adjacent to the electrode extraction portion.
By bonding the silicon substrate and the electrode substrate before the step of etching the silicon substrate, the silicon substrate can be easily handled and the yield can be improved.
Further, by providing the common electrode adjacent to the electrode extraction portion where the individual electrode is connected to the drive circuit, mounting on the droplet discharge device is facilitated.

In the method of manufacturing a droplet discharge head according to the present invention, the silicon thin film is formed from polycrystalline silicon or pseudo single crystal silicon.
By forming polycrystalline silicon or pseudo-single-crystal silicon by an ECR (Electron Cyclotron Resonance) sputtering method or the like, a silicon thin film and a diaphragm with high thickness accuracy can be formed.

In the method of manufacturing a droplet discharge head according to the present invention, the etching protective film is formed from silicon oxide or silicon nitride.
By forming the etching protective film from silicon oxide or silicon nitride, it is possible to easily form an etching protective film highly resistant to an alkaline etching solution such as an aqueous potassium hydroxide solution.

A droplet discharge device according to the present invention is equipped with any of the above-described droplet discharge heads.
By mounting the above-described droplet discharge head with high thickness accuracy of the diaphragm, a droplet discharge device with high printing performance can be obtained.

Embodiment 1. FIG.
FIG. 1 is a diagram showing a droplet discharge head according to Embodiment 1 of the present invention. 1A is a plan view of the droplet discharge head according to the first embodiment viewed from the electrode substrate 2 side, FIG. 1B is a cross-sectional view taken along line bb in FIG. 1A, and FIG. FIG. 1C is a cross-sectional view taken along the line cc in FIG. 1A, and FIG. 1D is a cross-sectional view taken along the line dd in FIG. 1 (b ′) is an enlarged view inside the circle surrounded by a dotted line in FIG. 1 (b), and FIG. 1 (d ′) is an enlarged view inside the circle surrounded by a dotted line in FIG. 1 (d).
The droplet discharge head according to the first embodiment of the present invention is mainly configured by bonding a cavity substrate 1, an electrode substrate 2, and a nozzle substrate 3. The nozzle substrate 3 is bonded to one surface of the cavity substrate 1, and the electrode substrate 2 is bonded to the opposite surface.

  The nozzle substrate 3 is made of, for example, silicon, and a plurality of nozzle holes 4 are formed. In the droplet discharge head according to the first embodiment, the straightness of droplets of ink or the like to be discharged is improved by using the two-stage nozzle hole 4 as shown in FIG. In addition, the nozzle substrate 3 is formed with a concave portion serving as a narrow groove-like orifice 8 for communicating a reservoir 7 and each discharge chamber 6 described below. The orifice 8 may be provided in the cavity substrate 1.

  The cavity substrate 1 is configured by, for example, performing predetermined processing as described below on a silicon substrate 1a made of single crystal silicon. The cavity substrate 1 is formed with a plurality of recesses that serve as discharge chambers 6 whose bottom walls are diaphragms 10. In addition, the cavity substrate 1 is formed with a recess that serves as a reservoir 7 for supplying droplets such as ink to the discharge chambers 6. Each discharge chamber 6 communicates with each nozzle hole 4 so that droplets accumulated in the discharge chamber 6 are discharged from the nozzle hole 4.

As shown in FIG. 1B ′, the vibration plate 10 is formed of a droplet-resistant protective film 11, a silicon thin film 12, and an insulating film 13. The droplet-resistant protective film 11 is made of, for example, silicon oxide and has a function of preventing the silicon substrate 1a from being etched by droplets inside the discharge chamber 6 and the reservoir 7. The anti-droplet protective film 11 is formed on the entire surface of the cavity substrate 1a on the nozzle substrate 3 side (see FIG. 6C).
The silicon thin film 12 is made of, for example, polycrystalline silicon or pseudo single crystal silicon, and a voltage is applied from the common electrode 15 formed on the silicon substrate 1a through the silicon substrate 1a.
The insulating film 13 is made of, for example, silicon oxide or silicon nitride, and has a function of preventing the silicon thin film 12 to which a voltage is applied from contacting the individual electrode 21 to cause a short circuit or dielectric breakdown. .

Further, as shown in FIG. 1D ′, an etching protection film 17 made of, for example, silicon oxide or silicon nitride is formed on the surface of the silicon substrate 1a on the electrode substrate 2 side. As described above, the anti-droplet protective film 11 is formed on the diaphragm 10 in place of the etching protective film 17 (see FIG. 6C). A silicon thin film 12 is formed on the etching protection film 17, and an insulating film 13 is formed on the silicon thin film 12. In the present invention, the silicon substrate 1a, the droplet-proof protective film 11, the silicon thin film 12, the insulating film 13, the etching protective film 17 and the like are collectively referred to as the cavity substrate 1.
Further, as shown in FIG. 1D ', the etching protection film 17 has an opening 18, and the silicon thin film 12 is in contact with the silicon substrate 1a in the opening 18. Note that the silicon thin film 12 is also formed on the opening 18 of the etching protective film 17. As described above, when the silicon thin film 12 and the silicon substrate 1a are in contact with each other in the opening 18 of the etching protection film 17, the silicon thin film 12 and the silicon substrate 1a are electrically connected.

An electrode substrate 2 made of, for example, borosilicate glass is bonded to the cavity substrate 10 side of the cavity substrate 1. In the electrode substrate 2, a plurality of elongated grooves 20 having a constant depth are formed at positions facing the diaphragm 10, and inside the grooves 20, a gap (gap) is formed between the diaphragm 10 and a constant interval. Opposing individual electrodes 21 are formed. The individual electrode 21 is formed, for example, by sputtering ITO (Indium Tin Oxide), and is formed up to the electrode extraction part 24 provided on the rear end face 23 side of the electrode substrate 2. In the electrode extraction unit 24, the individual electrode 21 is connected to a drive circuit (not shown).
In addition, an ink supply hole 25 communicating with the reservoir 7 is formed in the electrode substrate 2. The ink supply hole 25 is connected to a hole provided in the bottom wall of the reservoir 7, and is provided to supply droplets such as ink to the reservoir 7 from the outside.

  Here, the operation of the droplet discharge head shown in FIG. 1 will be described. Each individual electrode 21 is connected to a drive circuit (not shown) in the electrode extraction section 24 so that a pulse voltage is applied. A pulse voltage is applied to the silicon thin film 12 through a silicon substrate 1a from a drive circuit connected to the common electrode 15. At this time, a voltage is applied from the silicon substrate 1 a to the silicon thin film 12 through the opening 18 of the etching protective film 17. When a pulse voltage is applied between the individual electrode 21 and the silicon thin film 12 by the drive circuit, the vibration plate 10 bends to the individual electrode 21 side, and droplets of ink or the like accumulated in the reservoir 7 enter the discharge chamber 6. Flows in. In the first embodiment, when the vibration plate 10 is bent, the individual electrode 21 and the vibration plate 10 (insulating film 13) come into contact with each other. When the voltage applied between the individual electrode 21 and the silicon thin film 12 disappears, the diaphragm 10 returns to its original position, the pressure inside the discharge chamber 6 increases, and a liquid such as ink passes from the nozzle hole 4. Drops are ejected.

  2 to 7 are longitudinal sectional views showing manufacturing steps of the droplet discharge head according to the first embodiment of the present invention. 2 and 3 show the manufacturing process of the cavity substrate 1, FIG. 2 shows a bb section in FIG. 1, and FIG. 3 shows a dd section in FIG. FIG. 4 shows a manufacturing process of the electrode substrate 2 and shows a bb cross section of FIG. Further, FIGS. 5 to 7 show a manufacturing process from joining of the cavity substrate 1 and the electrode substrate 2 to completion of the droplet discharge head. FIGS. 5 and 6 are cross-sectional views taken along line bb in FIG. FIG. 7 shows a dd section in FIG. A method for manufacturing the droplet discharge head shown in FIG. 1 will be described below with reference to FIGS.

First, a silicon substrate 1a having a thickness of, for example, 525 μm is prepared (FIGS. 2A and 3A), and the polished surface is oxidized by plasma CVD (Chemical Vapor Deposition). An etching protective film 17 made of silicon or silicon nitride is formed (FIG. 2B).
Next, a resist is patterned on the surface of the etching protective film 17 by photolithography, and the etching protective film 17 is etched using a hydrofluoric acid aqueous solution or the like to remove the etching protective film 17 in the opening 18 (FIG. 3 ( b)).

Then, a silicon thin film 12 made of polycrystalline silicon or pseudo single crystal silicon is formed on the etching protection film 17 and in the opening 18 by, for example, ECR (Electron Cyclotron Resonance) sputtering method (FIG. 2C, FIG. c)). At this time, the silicon substrate 1 a and the silicon thin film 12 come into contact with each other in the opening 18.
When the silicon thin film 12 is formed of polycrystalline silicon, thermal CVD can be used. In this case, amorphous silicon is easily formed when the film is formed at 600 ° C. or lower. The ECR sputtering method can form a polycrystalline silicon thin film at a film forming temperature of about 500 ° C., and the film thickness uniformity is about ± 10% in the thermal CVD. A film can be formed with a uniformity of about ± 5%. When the film is formed by thermal CVD, a polycrystalline silicon thin film can be formed by laser annealing amorphous silicon obtained by thermally decomposing silane (SiH ₄ ) at about 550 ° C. When a pseudo single crystal silicon thin film is formed, the polycrystalline silicon thin film is once formed, and then laser annealing is performed to form the pseudo single crystal silicon thin film. Since any film forming method can be processed at a low temperature (600 ° C. or lower), generation of crystal defects in the silicon substrate 1a can be suppressed.
Then, an insulating film 13 made of silicon oxide or silicon nitride is formed on the silicon thin film 12 by plasma CVD or the like (FIGS. 2D and 3D).

Next, the process of manufacturing the electrode substrate 2 will be described with reference to FIG. First, a chromium / gold film 30 is formed by sputtering on one surface of a glass substrate 2a made of, for example, borosilicate glass and having a thickness of 1 mm (FIG. 4A). Then, a resist is patterned on the surface of the chrome / gold film 30 by photolithography, and the chrome / gold film 30 in the portion 20a to be the groove 20 is removed by etching (FIG. 4B).
Then, the glass substrate 2a is etched with a hydrofluoric acid aqueous solution or the like using the chromium / gold film 30 as an etching mask to form the groove 20 (FIG. 4C). Thereafter, the chrome / gold film 30 is removed by etching (FIG. 4D), and an ITO (Indium Tin Oxide) film 31 is formed by sputtering on the entire surface where the groove 20 is formed (FIG. 4E). .

Then, a resist is patterned on the surface of the ITO film 31 by photolithography, and the individual electrodes 21 are formed by etching (FIG. 4F). As described above, the individual electrode 21 is formed inside the groove 20.
Then, the electrode substrate 2 is completed by punching the ink supply holes 25 in the glass substrate 2a using, for example, a diamond drill (FIG. 4G).

Next, the silicon substrate 1a on which the etching protection film 17, the silicon thin film 12 and the insulating film 13 are formed in the steps of FIGS. 2 and 3, and the individual electrodes 21, the ink supply holes 25, etc. are formed in the step of FIG. The electrode substrate 2 is opposed (FIG. 5A) and anodic bonded (FIG. 5B).
Then, the surface opposite to the surface where the electrode substrate 2 of the silicon substrate 1a is bonded is ground by a grinder or the like until the thickness becomes, for example, 50 μm. At this time, the grinding trace which draws a parabola from the center remains on the surface of the silicon substrate 1a, and the surface roughness is about 0.1 μm.
Then, for example, the surface of the silicon substrate 1a is etched with a potassium hydroxide aqueous solution of 32% by weight and 80 ° C., and the work-affected layer generated in the grinding process by the grinder is removed (FIG. 5C). At this time, the surface of the silicon substrate 1a is further roughened by etching, but since the surface roughness is 1 μm or less, there is no problem when the nozzle substrate 3 is joined in a later step.

  Thereafter, a silicon oxide film 32 serving as an etching mask is formed on the surface of the silicon substrate 1a by, for example, CVD (FIG. 5D). Then, a resist is patterned on the surface of the silicon oxide film 32 by photolithography, so that the silicon oxide film 32 in the portion 6a serving as the discharge chamber 6, the portion 7a serving as the reservoir 7, and the portion 24a serving as the electrode extraction portion 24 is hydrofluoric acid aqueous solution. It removes by the etching which used etc. (FIG.5 (e)). At this time, the silicon oxide film 32 in the portion 7a to be the reservoir 7 is not completely removed but half-etched.

  Then, for example, the silicon substrate 1a is etched with a 35 wt% potassium hydroxide aqueous solution at 80 ° C. to form the recesses 6b to be the discharge chambers 6 and the recesses 24b to be the electrode extraction parts 24 halfway. Then, for example, the silicon oxide film 32 is half-etched with a hydrofluoric acid aqueous solution to remove the silicon oxide film 32 left in the portion 7 a to be the reservoir 7. Thereafter, the etching of the silicon substrate 1a is continued with, for example, a 35 wt% potassium hydroxide aqueous solution at 80 ° C. to form a recess 6b serving as the discharge chamber 6, a recess 7b serving as the reservoir 7, and a recess 24b serving as the electrode extraction portion 24. (FIG. 6A). At this time, etching stops at the portion of the etching protection film 17 made of silicon oxide or silicon nitride. In addition, the concave portion 7b serving as the reservoir 7 that delayed the start of etching can leave the silicon substrate 1a on the bottom wall thick.

Thereafter, all of the silicon oxide film 32 formed on the silicon substrate 1a is removed by, for example, a hydrofluoric acid aqueous solution (FIG. 6B). At this time, the etching protective film 17 formed on the bottom wall of the concave portion 6b serving as the discharge chamber 6 and the concave portion 24b serving as the electrode extraction portion 24 is also removed.
In the process from the anodic bonding process of FIG. 5B to the process of FIG. 6B, the gap (gap) between the individual electrode 21 and the insulating film 13 is hermetically sealed. The etchant does not enter the gap.

Next, a droplet-proof protective film 11 made of silicon oxide is formed on the surface of the silicon substrate 1a by, for example, plasma CVD. As a result, the diaphragm 10 including the anti-drop protection film 11, the silicon thin film 12, and the insulating film 13 is completed.
Then, the droplet-resistant protective film 11 of the common electrode forming portion 34 is removed by dry etching using, for example, a metal mask (FIG. 7A), and the common electrode 15 made of platinum, for example, by sputtering using the metal mask. Is formed in the common electrode forming portion 34 (FIG. 7B).
Then, a metal mask having an opening corresponding to the shape of the recess 24b to be the electrode extraction portion 24 is overlapped on the silicon substrate 1a and dry etching is performed, so that the droplet-resistant protective film 11 in the recess 24b to be the electrode extraction portion 24 is formed. Then, the silicon thin film 12 and the insulating film 13 are removed (FIG. 6C). Thereby, the electrode extraction part 24 is formed, and the gap between the diaphragm 10 and the individual electrode 21 is opened.

Thereafter, a sealing material 35 is applied along the end of the electrode extraction portion 24 to seal the gap between the diaphragm 10 and the individual electrode 21 (FIG. 6D).
Finally, the nozzle substrate 3 is bonded to the silicon substrate 1a using an adhesive or the like (FIGS. 6E and 7C), and the liquid droplet ejection head is diced (cut) into individual head chips. Completed (FIGS. 6 (f) and 7 (d)).

In the first embodiment, the opening 18 is formed in the etching protection film 17 on the silicon substrate 1a, and the silicon thin film 12 is formed on the etching protection film 17 and in the opening 18, so that the silicon substrate 1a is interposed through the silicon substrate 1a. A voltage can be applied to the silicon thin film 12.
Further, by forming a polycrystalline silicon thin film or a pseudo single crystal silicon thin film by an ECR sputtering method or the like, the silicon thin film 12 and the diaphragm 10 with high thickness accuracy can be formed.

Embodiment 2. FIG.
FIG. 8 is a view showing a droplet discharge head according to Embodiment 2 of the present invention. 8A is a plan view of the droplet discharge head according to the second embodiment as viewed from the electrode substrate 2 side, FIG. 8B is a cross-sectional view taken along line bb in FIG. 8A, and FIG. FIG. 8C is a cross-sectional view taken along the line cc in FIG. 8A, and FIG. 8D is a cross-sectional view taken along the line dd in FIG. FIG. 8B ′ is an enlarged view inside the circle surrounded by a dotted line in FIG. 8B, and FIG. 8D ′ is an enlarged view inside the circle surrounded by a dotted line in FIG. 8D.
The droplet discharge head according to the second embodiment is substantially the same as the droplet discharge head according to the first embodiment except for the configuration of the portion for applying a voltage to the silicon thin film 12, and only the changes will be described. In addition, the same components as those of the droplet discharge head according to the first embodiment will be described with the same reference numerals.

In the droplet discharge head according to the second embodiment, the opening 18 is not provided in the etching protection film 17, and instead, a common electrode forming unit 40 is formed at a position adjacent to the electrode extraction unit 24. A voltage is directly applied to the silicon thin film 12 from the formed common electrode 15. FIG. 8 shows a liquid droplet ejection head having two common electrode forming portions 40 adjacent to both ends in the longitudinal direction of the electrode extraction portion 24.
In the common electrode forming portion 40, the etching protective film 17 is removed so that the silicon thin film 12 and the etching protective film 17 do not overlap each other, and the common electrode 15 formed here and the silicon thin film 12 are in direct contact with each other. It has become. For this reason, similarly to the droplet discharge head according to the first embodiment, it is possible to apply a voltage to the silicon thin film 12 by connecting a drive circuit (not shown) to the common electrode 15.

  FIG. 9 is a longitudinal sectional view showing a manufacturing process of the droplet discharge head according to the second embodiment of the present invention. FIG. 9 shows a manufacturing process after the process up to FIG. 6B of the manufacturing process of the droplet discharge head shown in the first embodiment is completed, and shows a section taken along the line dd of FIG. The manufacturing method of the droplet discharge head according to the second embodiment is substantially the same as the manufacturing method of the droplet discharge head according to the first embodiment except that the opening 18 is not formed in FIG. Only the changes will be described. Hereinafter, the manufacturing method of the droplet discharge head shown in FIG. 8 will be described with reference to FIG.

  First, a bonded substrate that has been processed up to the step of FIG. 6B of the manufacturing method of the droplet discharge head according to the first embodiment is prepared (FIG. 9A). In the manufacturing method of the droplet discharge head according to the second embodiment, when the recess 24b to be the electrode extraction portion 24 is formed in the etching process of the silicon substrate 1a in FIGS. 5 (e) and 6 (a). It is assumed that the concave portion 40b to be the common electrode forming portion 40 is formed. For example, in the etching process shown in FIGS. 5 (e) and 6 (a), the concave portions 40b to be the common electrode forming portions 40 are formed by widening both ends in the longitudinal direction of the concave portions 24b to be the electrode extraction portions 24. This should be done (see FIG. 8A). In the second embodiment, it is assumed that the concave portion 24b serving as the electrode extraction portion 24 and the concave portion 40b serving as the common electrode forming portion 40 communicate with each other. At this time, the etching protective film 17 is exposed in the concave portion 40 b that becomes the common electrode forming portion 40.

  Then, for example, the etching protective film 17 exposed in the concave portion 40b that becomes the common electrode forming portion 40 is removed by etching using a hydrofluoric acid aqueous solution to form the common electrode forming portion 40, and then a metal mask is used. The common electrode 15 made of platinum or the like is formed on the common electrode forming portion 40 by sputtering (FIG. 9B). At this time, the common electrode 15 and the silicon thin film 12 are in direct contact with each other in the common electrode forming unit 40.

Then, a droplet-resistant protective film 11 made of, for example, silicon oxide is formed on the surface of the silicon substrate 1a and the common electrode 15 (FIG. 9C). Thereafter, the recess 24b to be the electrode extraction portion 24 and a metal mask having an opening corresponding to the shape of the common electrode forming portion 40 are overlaid on the silicon substrate 1a, and dry etching is performed. The protective film 11 is removed, and the anti-droplet protective film 11, the silicon thin film 12, and the insulating film 13 are removed from the concave portion 24b serving as the electrode extraction portion 24 (FIG. 9D). At this time, since the common electrode 15 made of platinum or the like functions as an etching mask for dry etching, the silicon thin film 12 and the insulating film 13 under the common electrode 15 are not etched.
Finally, the nozzle substrate 3 is bonded to the silicon substrate 1a using an adhesive or the like (FIG. 9 (e)), and dicing (cutting) into individual head chips is completed (FIG. 9 (FIG. 9). f)).

In the second embodiment, the silicon substrate 1a is etched to expose the etching protection film 17, and the etching protection film 17 in the portion is removed to form the common electrode 15 in contact with the silicon thin film 12. A voltage can be applied to the thin film 12.
In addition, by forming polycrystalline silicon or pseudo single crystal silicon by an ECR sputtering method or the like, the silicon thin film 12 and the diaphragm 10 with high thickness accuracy can be formed.
Further, the common electrode forming portion 40 is provided adjacent to the electrode extraction portion 24 where the individual electrode 21 is connected to the drive circuit, and the height of the mounting portion of the individual electrode 21 and the height of the common electrode 15 is substantially the same. , Mounting on a droplet discharge device by FPC (Flexible Printed Card) or the like becomes easy.

Embodiment 3. FIG.
FIG. 10 is a diagram showing an example of a droplet discharge device according to Embodiment 3 of the present invention. A droplet discharge apparatus 100 shown in FIG. 10 is a general ink jet printer, and includes the droplet discharge head shown in the first or second embodiment. Since the droplet discharge head shown in Embodiment 1 or Embodiment 2 is a droplet discharge head with high thickness accuracy of the silicon thin film 12 (the vibration plate 10), the droplet discharge apparatus 100 according to Embodiment 3 includes: The printing performance is high. Note that the droplet discharge device 100 as shown in FIG. 10 can be manufactured using a known manufacturing method.

  In addition to the ink jet printer as shown in FIG. 10, the droplet discharge heads shown in Embodiments 1 and 2 of the present invention are used for manufacturing an organic EL display device, a color filter for a liquid crystal display device, and a DNA device. It can also be used for the production of

  The droplet discharge head, the manufacturing method thereof, and the droplet discharge apparatus according to the present invention are not limited to the above-described embodiments, and can be changed within the scope of the idea of the present invention. For example, in the second embodiment, the common electrode forming part 40 and the common electrode 15 may be provided at positions not adjacent to the electrode extraction part 24.

1 is a diagram illustrating a droplet discharge head according to a first embodiment of the present invention. FIG. 6 is a cross-sectional view taken along the line bb showing the manufacturing process of the droplet discharge head according to the first embodiment. FIG. 4 is a dd sectional view showing a manufacturing process of the droplet discharge head according to the first embodiment. FIG. 6 is a cross-sectional view taken along the line bb showing the manufacturing process of the droplet discharge head according to the first embodiment. FIG. 6 is a cross-sectional view taken along the line bb showing the manufacturing process of the droplet discharge head according to the first embodiment. FIG. 6 is a cross-sectional view taken along the line bb showing the manufacturing process of the droplet discharge head according to the first embodiment. FIG. 4 is a dd sectional view showing a manufacturing process of the droplet discharge head according to the first embodiment. FIG. 5 is a diagram illustrating a droplet discharge head according to a second embodiment of the invention. FIG. 11 is a dd sectional view showing a manufacturing process of the droplet discharge head according to the second embodiment. The figure which showed the example of the droplet discharge apparatus which concerns on Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cavity substrate, 1a Silicon substrate, 2 Electrode substrate, 3 Nozzle substrate, 4 Nozzle hole, 6 Discharge chamber, 7 Reservoir, 8 Orifice, 10 Diaphragm, 11 Anti-drop protection film, 12 Silicon thin film, 13 Insulating film, 15 Common electrode, 17 etching protective film, 18 opening, 20 groove, 21 individual electrode, 23 rear end face, 24 electrode takeout part, 25 ink supply hole, 40 common electrode formation part.

Claims (15)

A silicon substrate;
An etching protective film formed on one surface of the silicon substrate;
A silicon thin film that is formed on the etching protective film and forms a part of a diaphragm driven by electrostatic force;
The etching protection film has an opening, and the silicon thin film is also formed in the opening, and is in contact with the silicon substrate in the opening and is electrically connected to the silicon substrate. Droplet discharge head.   The droplet discharge head according to claim 1, wherein a common electrode is formed on the silicon substrate, and a voltage is applied from the common electrode to the silicon thin film through the silicon substrate. A silicon substrate;
An etching protective film formed on one surface of the silicon substrate;
A silicon thin film that is formed on the etching protective film and forms a part of a diaphragm driven by electrostatic force;
The silicon thin film has a portion that does not overlap with the etching protective film, a common electrode is formed on a portion of the silicon thin film that does not overlap with the etching protective film, and a voltage is applied from the common electrode to the silicon thin film. A droplet discharge head that is characterized.   An electrode substrate that is bonded to the silicon substrate on which the common electrode is formed; and an individual electrode that is formed on the electrode substrate and that drives the diaphragm. The electrode substrate is connected to the drive circuit. The liquid droplet ejection head according to claim 3, further comprising an electrode extraction portion, wherein the common electrode is provided adjacent to the electrode extraction portion.   The droplet discharge head according to claim 1, wherein an insulating film is formed on the silicon thin film.   The liquid droplet ejection head according to claim 1, wherein the silicon thin film is formed of polycrystalline silicon or pseudo single crystal silicon.   The liquid droplet ejection head according to claim 1, wherein the etching protection film is made of silicon oxide or silicon nitride. Forming an etching protective film on one surface of the silicon substrate;
Forming an opening in the etching protective film;
Forming a silicon thin film constituting a part of a diaphragm driven by electrostatic force on the etching protection film and on the opening.   9. The droplet according to claim 8, further comprising a step of forming an insulating film on the silicon thin film and a step of etching the silicon substrate on which the insulating film is formed after the step of forming the silicon thin film. Manufacturing method of the discharge head. Forming an etching protective film on one surface of the silicon substrate;
Forming a silicon thin film constituting a part of a diaphragm driven by electrostatic force on the etching protective film;
Etching the silicon substrate such that a portion of the etching protection film is exposed;
Removing the exposed portion of the etching protection film to form a portion where the silicon thin film does not overlap the etching protection film;
Forming a common electrode on a portion of the silicon thin film that does not overlap the etching protective film.   11. The method of manufacturing a droplet discharge head according to claim 10, further comprising a step of forming an insulating film on the silicon thin film before the step of etching the silicon substrate.   Before the step of etching the silicon substrate, the step of bonding the silicon substrate on which the insulating film is formed to an electrode substrate on which an individual electrode for driving the vibration plate is formed, 12. The method of manufacturing a droplet discharge head according to claim 11, wherein an electrode take-out portion for connecting an individual electrode to a drive circuit is provided, and the common electrode is formed adjacent to the electrode take-out portion.   The method for manufacturing a droplet discharge head according to claim 8, wherein the silicon thin film is formed of polycrystalline silicon or pseudo single crystal silicon.   The method for manufacturing a droplet discharge head according to claim 8, wherein the etching protective film is formed of silicon oxide or silicon nitride. A liquid droplet ejection apparatus, comprising the liquid droplet ejection head according to claim 1.

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