JP2002046266A - Ink jet head and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of ink jet head in which the interval of gap is stabilized while reducing the variation thereof. SOLUTION: A silicon thermal oxide film becoming a first insulation layer 1 is grown by 2.0 μm on a <100> silicon wafer becoming a supporting substrate 11. A silicon oxide nitride film becoming a second insulation layer 2 is then formed on the surface of the first insulation layer 1 by performing annealing at 750-950 deg.C using N2O or NO gas. Furthermore, a silicon oxide film becoming a third insulation layer 3 is formed thus forming an insulation film of three layer structure. Subsequently, a resist pattern 21 and the third insulation layer 3 having an open area ratio varied in correspondence with the gap shape are etched simultaneously thus transferring the resist pattern 21 to the third insulation layer 3. When plasma emission is monitored during dry etching and an emission wavelength derived from nitrogen is monitored, the silicon oxide nitride film in the third insulation layer 3 is eliminated and exposure of the silicon oxide nitride film in the second insulation layer 2 is detected thus ending the etching.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ink jet head and a method of manufacturing the same, and more particularly, to a method of forming a gap provided between a diaphragm and an electrode substrate in a recording head of an ink jet recording apparatus using electrostatic force. ,
The present invention relates to a technique applicable to an inkjet head such as a printer, a copier, and a facsimile.

[0002]

2. Description of the Related Art As a prior art relating to a method for forming a gap provided between a diaphragm and an electrode substrate of an ink jet head using electrostatic force, for example, Japanese Patent Application Laid-Open No. H06-0718
No. 82, Japanese Patent Application Laid-Open No. 9-039235, Japanese Patent Application Laid-Open
There is one disclosed in Japanese Patent Application Laid-Open No. 193375. Japanese Patent Application Laid-Open No. Hei 6-07882 discloses that the diaphragm is displaced by an electrostatic force generated when a voltage is applied between the diaphragm and an electrode facing the diaphragm at a predetermined interval.
A method of forming an SiO ₂ film as a gap spacer on either a vibration plate or an electrode substrate in an ink jet head of a type that ejects ink (hereinafter referred to as an electrostatic ink jet head) is disclosed.
Various methods for forming the O ₂ film, such as a thermal oxide film, vapor deposition, sputtering, and CVD, are disclosed, but examples are disclosed in which all are formed of a SiO ₂ film.

Japanese Patent Application Laid-Open No. 9-039235 discloses an electrostatic ink-jet head in which a gap (gap) between a diaphragm and an electrode has a relatively large portion and a small portion. The structure that changes gradually makes it possible to lower the driving voltage and to control the ink droplet ejection amount in a stepwise manner. Is formed by forming a step on the stairs and placing electrodes thereon. The detailed production method is not specifically disclosed.

Japanese Patent Application Laid-Open No. 9-193375 discloses a non-parallel gap between a diaphragm (first electrode) and a counter electrode (second electrode) in an electrostatic ink jet head. In this way, the non-parallel gap is formed by forming a non-parallel step in the substrate, and the electrodes are arranged thereon. As a result, a non-parallel gap is formed. The detailed production method is not specifically disclosed.

The present applicant has previously proposed the following method for forming a gap provided between the diaphragm and the electrode substrate of an ink jet head utilizing electrostatic force. (1) Electrostatic inkjet head In the electrostatic inkjet head, the gap between the diaphragm electrode and the substrate electrode is reduced from the center of the gap toward the periphery, thereby reducing the voltage at which the diaphragm is displaced. By further optimizing the shape, the voltage at which the diaphragm is displaced is further reduced and the amount of displacement is increased. Also,
By using silicon as the material for the electrode substrate, an inexpensive electrostatic inkjet head can be obtained, or the process temperature can be lowered by forming the material from an anodic bondable material. The configuration of the non-parallel gap is realized by forming a concave portion having a smoothly varying depth in the substrate and arranging an electrode thereon. As a method of manufacturing a concave portion having a smoothly changing depth, a photoresist layer is formed on an electrode substrate, a gap is formed in the photoresist layer by photolithography, and the photoresist There has been proposed a method of forming a desired gap shape in an electrode substrate material by performing isotropic and / or anisotropic etching of the material.

As a specific embodiment, after a resist is applied on an electrode substrate (or an insulating film on the electrode substrate, hereinafter abbreviated), a region through which light is transmitted is formed so that the transmitted light is scattered. Using a photomask, a resist layer with a deep shape at the center and a shallow shape at the periphery of the mask is formed. By forming a resist layer with a smooth convex shape toward the diaphragm side, and then forming a resist layer by a method of smoothing the resist shape by further heat treatment, the resist and the electrode substrate are simultaneously etched to form a resist. Has been proposed for transferring the shape of the electrode to the electrode substrate.

(2) Manufacturing method of non-parallel gap A non-parallel gap is formed by forming a non-parallel step in a substrate or a single insulating film formed on the substrate, and arranging electrodes thereon. As a method of manufacturing a non-parallel step shape, a photoresist layer is formed on a substrate, and the non-parallel step is formed on the photoresist layer by photolithography using a mask whose transmittance gradually changes. A method has been proposed in which a shape is formed, the photoresist layer and the substrate material are simultaneously etched, and the non-parallel step shape formed in the photoresist layer is transferred to the substrate material.

(3) Manufacturing method of non-parallel gap (Japanese Patent Application No. 11-349938, “Electrostatic actuator / ink jet head and manufacturing method thereof”) A non-parallel gap is formed in a substrate or on a substrate. A non-parallel step is formed in one insulating film, and an electrode is arranged on the non-parallel step. As a method for manufacturing the non-parallel step shape, a method similar to the above (2) is used. A photoresist layer is formed, a non-parallel step is formed in the photoresist layer by photolithography using a mask whose transmittance gradually changes, and the photoresist layer and the substrate material are simultaneously etched to form a photoresist. The method of transferring the non-parallel step shape formed in the layer to the substrate material, wherein the resist thickness, resist shape, etching selectivity, two-step etching, etc. ).

[0009]

SUMMARY OF THE INVENTION The above-mentioned JP-A-6-071
No. 882 discloses a single-layer SiO ₂ film as a gap spacer between a diaphragm and an electrode, and the gap interval is set to 0.05 μm to 0.20 μm. Is not disclosed,
In addition, it does not disclose a method of manufacturing a gap and a method of controlling a gap interval.

The one disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 9-193375 and the above-mentioned ones (1), (2) and (3) proposed by the applicant of the present invention are all in the substrate or on the substrate. Non-parallel steps are formed in a single insulating film formed on the substrate, and the depth of the steps is controlled by the etch rate ratio with the resist or the etch rate and the etching time. To be done,
Variations in the gap interval tend to be relatively large.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and has been described in an electrostatic ink jet head.
An object of the present invention is to provide a manufacturing method for stabilizing a gap interval having a great influence on a driving voltage and an ink extraction amount and reducing the variation.

[0012]

According to a first aspect of the present invention, there is provided a diaphragm which forms a part of a liquid chamber communicating with a nozzle for discharging a recording liquid and has a common electrode; An electrode substrate having individual electrodes opposed to each other via a gap, applying a drive voltage between the common electrode and the individual electrodes, deforming the diaphragm by electrostatic force, and applying the recording liquid to the recording liquid. In an inkjet head that performs recording on a recording medium by discharging from a nozzle, an insulating layer for forming the gap is formed on the electrode substrate, and the insulating layer includes an oxide film serving as a first insulating layer; 2 is characterized by having a three-layer structure in which an oxynitride film as an insulating layer and an oxide film as a third insulating layer are sequentially laminated.

According to a second aspect of the present invention, in the first aspect, the first insulating layer comprises a silicon oxide film, the second insulating layer comprises a silicon oxynitride film, and the third insulating layer Is made of a silicon oxide film.

According to a third aspect of the present invention, there is provided a diaphragm which forms a part of a liquid chamber which communicates with a nozzle for discharging a recording liquid and has a common electrode, and an individual electrode with a gap with respect to the diaphragm. Has an electrode substrate disposed opposite thereto, applies a drive voltage between the common electrode and the individual electrode, deforms the vibration plate by electrostatic force, and discharges the recording liquid from the nozzle to perform recording. In an inkjet head that performs recording on a medium, an insulating layer for forming the gap is formed on the electrode substrate, and the insulating layer includes a silicon oxide film as a first insulating layer and a second insulating layer. It has a three-layer structure in which a silicon nitride film and a silicon oxide film as a third insulating layer are sequentially stacked.

According to a fourth aspect of the present invention, in the second or third aspect, the silicon oxide film as the first insulating layer is formed of a silicon thermal oxide film.

According to a fifth aspect of the present invention, in the second aspect of the present invention, a polysilicon layer is formed on the surface of the first insulating layer after forming a silicon oxide film as the first insulating layer on the electrode substrate. After forming a silicon oxynitride film as a second insulating layer by oxynitriding the polysilicon layer,
The method is characterized in that the third insulating layer is formed on the surface of the second insulating layer.

According to a sixth aspect of the present invention, in the second aspect of the invention, after forming a silicon oxide film as the first insulating layer on the electrode substrate, the surface of the first insulating layer is subjected to the nitrogen annealing by nitrogen annealing. After forming a silicon oxynitride film as the second insulating layer, the third insulating layer is formed on the surface of the second insulating layer.

According to a seventh aspect of the present invention, in the second aspect of the present invention, after a silicon oxide film as the first insulating layer is formed on the electrode substrate, nitrogen is ion-implanted on the surface of the first insulating layer. After the ions are implanted to form the second insulating layer, the third insulating layer is formed on the surface of the second insulating layer.

The invention of claim 8 is characterized in that, in any one of the inventions of claims 5 to 7, the silicon oxide film as the first insulating layer is made of a silicon thermal oxide film.

According to a ninth aspect of the present invention, there is provided a diaphragm which forms a part of a liquid chamber which communicates with a nozzle for discharging a recording liquid, and has a common electrode, and an individual electrode with a gap with respect to the diaphragm. Has an electrode substrate disposed opposite thereto, applies a drive voltage between the common electrode and the individual electrode, deforms the vibration plate by electrostatic force, and discharges the recording liquid from the nozzle to perform recording. In a method of manufacturing an ink jet head for performing recording on a medium, after forming a silicon oxide film as a first insulating layer on the electrode substrate, boric acid, phosphorus, arsenic, or nitrogen is ion-implanted into the first insulating layer. Is implanted to a desired depth, and a second insulating layer is formed in the middle of the first insulating layer to form an insulating layer having a three-layer structure.

[0021]

(Embodiment 1) FIG. 1 is a sectional view of a main part of an ink jet head actuator for explaining an embodiment of an ink jet head according to the present invention. Reference numeral 2 denotes a second insulating film, 3 denotes a third insulating film, 4 denotes an adhesive layer, 11 denotes a support substrate, 12 denotes a counter electrode, 13 denotes an insulating film, 14 denotes a gap, 15 denotes a diaphragm, and 16 denotes a partition. It is. The main part of the actuator of this configuration includes a support substrate 11, a counter electrode 12,
An insulating film 13, a first insulating film 1, a second insulating film 2, a third insulating film 3, an adhesive layer 4, and a diaphragm 15;
Between the diaphragm 15 and the counter electrode 12 (more precisely, the insulating film 1
3), a minute gap 14 is formed. When a voltage is applied between the diaphragm 15 and the counter electrode 12, the diaphragm 15 is displaced toward the counter electrode 12 by electrostatic force, Thereafter, when the voltage is returned to 0, the displaced diaphragm 15 ejects ink by the force of returning to the original position by the elastic force.

The gap 14 between the diaphragm 15 and the counter electrode 12 is determined by the distance formed by the recess formed in the third insulating film 3 and the adhesive layer 4 also used as a spacer. The size is equal to the thickness of the counter electrode 12.

In the actuator according to the present embodiment, on one side (left side in FIG. 1), the center portion (the right side in FIG. 1) extends from the gap end for the purpose of lowering the driving voltage and controlling the ejected ink droplet amount in a plurality of steps. In the remaining portion, the gap 14 has a shape such that the diaphragm 15 and the counter electrode 12 are parallel to each other so that the distance between the diaphragm 15 and the counter electrode 12 gradually increases in the direction (direction). The insulating film 13 on the counter electrode 12 prevents a short circuit between the diaphragm 15 and the counter electrode 12, and an insulating film having the same function may be formed on the diaphragm 15 side. In the case where the diaphragm 15 and the counter electrode 12 are operated by a driving method in which they do not come into contact with each other, the operation can be omitted. Further, the gap shape of the present embodiment is:
This is merely an example, and other gap shapes may be used according to the purpose.

The present invention relates to a method of forming the gap 14 between the diaphragm 15 and the electrode 12 opposed to the diaphragm 15 with the gap 14 interposed therebetween. Similarly, an ink jet head is formed by assembling components such as an ink supply path, a fluid resistance, and a nozzle plate to the actuator having the configuration of the embodiment shown in FIG.

FIG. 2 is a schematic diagram of a process flow for explaining one embodiment of the method of manufacturing an ink jet according to the present invention. First, a 2.0 μm thick silicon thermal oxide film serving as the first insulating layer 1 is grown on a <100> silicon wafer serving as the support base 11 (FIG. 2A). Then, N ₂ O
Alternatively, annealing is performed at 750 to 950 ° C. using NO gas to form a silicon oxynitride film to be the second insulating layer 2 on the surface of the first insulating layer 1 (FIG. 2B). Further, an insulating film having a three-layer (laminated) structure is formed on the support base 11 by forming a silicon oxide film to be the third insulating layer 3 (FIG. 2C).

After that, a resist is applied by spin coating, and in order to obtain a desired gap shape, exposure and development are performed using a mask having a transmittance changed by changing an aperture ratio corresponding to the gap shape. Is performed to form a resist pattern 21 having a large slope corresponding to the gap shape (FIG. 2D). By simultaneously etching the resist pattern 21 and the third insulating layer 3, the shape of the resist is transferred to the third insulating film 3. In this embodiment, etching was performed by a dry etch method using CF ₄ / O ₂ gas plasma.

In this embodiment, the plasma emission is monitored during the dry etching. For example, by monitoring the emission wavelength derived from nitrogen, the silicon oxide film as the third insulating layer 3 is eliminated, and the second insulating layer 3 is removed. By detecting that the silicon oxynitride film as the insulating layer 2 has been exposed and terminating the etching, the gap interval can be controlled by the thickness of the silicon oxide film as the third insulating layer 3. .

In this embodiment, the etching is performed under the etching conditions such that the silicon oxide film as the third insulating layer 3 and the silicon oxynitride film as the second insulating layer 2 have the same etching speed. The interface between the silicon oxide film as the third insulating layer 3 and the silicon oxynitride film as the second insulating layer 2 prevents the gap shape from becoming discontinuous.

(Example 2) <100 to be the support base 11
> After forming a silicon thermal oxide film to be the first insulating layer 1 on the silicon wafer, a silicon nitride film is formed as the second insulating layer 2. Then, according to the method described in Example 1,
The third insulating layer 3 and the resist pattern 21 are formed.
Although the resist shape is transferred to the third insulating film 3 by simultaneously etching the resist pattern 21 and the third insulating layer 3 as in the first embodiment,
A silicon nitride film as the second insulating layer 2 is formed by a CVD method or the like. Since the etching speed of the silicon nitride film is low with respect to the etching conditions of the silicon oxide film as the third insulating layer 3, the progress of the etching can be stopped by the silicon nitride film. Can be controlled by the thickness of the silicon oxide film that is the third insulating layer 3.

(Embodiment 3) FIG. 3 is a view for explaining another embodiment of the method of manufacturing an ink jet head according to the present invention. As a method of forming an insulating layer having a three-layer structure according to the first embodiment, a silicon thermal oxide film serving as a first insulating layer 1 is formed on a <100> silicon wafer serving as a support base 11 and then a polysilicon film is formed. 22 (FIG. 3)
(A)). Thereafter, 900 to 950 ° C. using NO gas
Then, there is a method of oxidizing the polysilicon film 22 to form a silicon oxynitride film. After that, the third insulating layer 3 and the resist 21 are formed by the method described in the first embodiment, and the end point is detected by dry etching.

Further, as a method of forming the insulating layer having the three-layer structure described in the first embodiment, the support
> After forming a silicon thermal oxide film to be the first insulating layer 1 on a silicon wafer, a desired ion species, for example, boric acid, phosphorus, arsenic, nitrogen is implanted into the silicon thermal oxide film by ion implantation (for example, In the case of nitrogen ions, by setting the implantation energy to 90 to 100 KeV, 200
nitrogen ions can be implanted to a thickness of about nm) to form a layer (second insulating layer) 23 having a high concentration of implanted species in the insulating layer. A film can be formed.

[0032]

(1) According to the first aspect of the present invention, when a step serving as a gap is formed by dry etching in a three-layered insulating layer formed on an electrode substrate, the third insulating layer is used. In the process of etching from a certain silicon oxide film to the silicon oxynitride film as the second insulating layer, by monitoring and utilizing the change in plasma emission during dry etching, the end point can be detected, and the gap step can be detected. Processing with less variation determined by the thickness of the third insulating layer is possible.

(2) According to the third aspect of the present invention, when forming a step serving as a gap in a three-layered insulating layer formed on an electrode substrate, a silicon oxide film as a first insulating layer and a second insulating layer are formed. Utilizing the fact that the etching selectivity with respect to the silicon nitride film as the second insulating layer is relatively large, it is possible to stop the progress of etching on the surface of the silicon nitride film as the second insulating layer, However, processing with less variation determined by the film thickness of the third insulating layer is possible.

(3) According to the second, fourth, sixth, seventh, and ninth aspects of the present invention, processing with less variation can be performed by the same method as that of the first aspect.

(4) According to the fourth and eighth aspects of the present invention, when forming the second insulating layer according to the second, third, fifth, sixth and seventh aspects, more stable reliability in film quality, film thickness, etc. A highly insulating layer can be formed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of an ink-jet head actuator for explaining an embodiment of an ink-jet head according to the present invention.

FIG. 2 is a schematic diagram of a process flow for explaining an embodiment of a method of manufacturing an ink jet according to the present invention.

FIG. 3 is a view for explaining another embodiment of the method for manufacturing an ink jet head according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st insulating film, 2 ... 2nd insulating film, 3 ... 3rd insulating film, 4 ... adhesive layer, 11 ... support substrate, 12 ... counter electrode, 1
3 insulating film, 14 gap, 15 diaphragm, 16 partition, 21 resist pattern, 22 polysilicon film,
23: Layer with high concentration of implanted species.

Claims (9)

[Claims] 1. A diaphragm which forms a part of a liquid chamber which communicates with a nozzle for discharging a recording liquid and has a common electrode, and an individual electrode opposed to the diaphragm with a gap interposed therebetween. An electrode substrate, a driving voltage is applied between the common electrode and the individual electrodes to deform the diaphragm by electrostatic force, and the recording liquid is discharged from the nozzles to perform recording on a recording medium. In the inkjet head, an insulating layer for forming the gap is formed on the electrode substrate, and the insulating layer includes an oxide film serving as a first insulating layer and an oxynitride film serving as a second insulating layer. An ink-jet head having a three-layer structure in which an oxide film serving as a third insulating layer is sequentially stacked. 2. The ink jet head according to claim 1, wherein said first insulating layer comprises a silicon oxide film, said second insulating layer comprises a silicon oxynitride film, and said third insulating layer comprises silicon. An ink jet head comprising an oxide film. 3. A diaphragm that forms a part of a liquid chamber that communicates with a nozzle that discharges a recording liquid and has a common electrode, and an individual electrode that is opposed to the diaphragm with a gap interposed therebetween. An electrode substrate, a driving voltage is applied between the common electrode and the individual electrodes to deform the diaphragm by electrostatic force, and the recording liquid is discharged from the nozzles to perform recording on a recording medium. In the inkjet head, an insulating layer for forming the gap is formed on the electrode substrate, and the insulating layer includes a silicon oxide film as a first insulating layer and a silicon nitride film as a second insulating layer. An ink-jet head having a three-layer structure in which a silicon oxide film is sequentially stacked on a third insulating layer. 4. The ink jet head according to claim 2, wherein the silicon oxide film as the first insulating layer is made of a silicon thermal oxide film. 5. The method for manufacturing an ink jet head according to claim 2, wherein a silicon oxide film serving as the first insulating layer is formed on the electrode substrate, and then a polysilicon layer is formed on the surface of the first insulating layer. Forming a silicon oxynitride film as a second insulating layer by oxynitriding the polysilicon layer, and then forming the third insulating layer on the surface of the second insulating layer. Of manufacturing an inkjet head. 6. The method of manufacturing an ink jet head according to claim 2, wherein after forming a silicon oxide film as the first insulating layer on the electrode substrate, the surface of the first insulating layer is subjected to nitrogen annealing. After forming a silicon oxynitride film as a second insulating layer, the third insulating layer is formed on the surface of the second insulating layer.
A method for manufacturing an ink jet head, comprising forming an insulating layer as described above. 7. The method for manufacturing an ink-jet head according to claim 2, wherein after forming a silicon oxide film as the first insulating layer on the electrode substrate, the surface of the first insulating layer is ion-implanted. Implanting nitrogen ions into the second
After forming the insulating layer, the third insulating layer is formed on the surface of the second insulating layer.
A method for manufacturing an ink jet head, comprising forming an insulating layer as described above. 8. The method for manufacturing an ink jet head according to claim 5, wherein the silicon oxide film as the first insulating layer is made of a silicon thermal oxide film. Production method. 9. A diaphragm which forms a part of a liquid chamber communicating with a nozzle for discharging a recording liquid and has a common electrode, and an individual electrode which is opposed to the diaphragm with a gap interposed therebetween. An electrode substrate, a driving voltage is applied between the common electrode and the individual electrodes to deform the diaphragm by electrostatic force, and the recording liquid is discharged from the nozzles to perform recording on a recording medium. In the method for manufacturing an ink jet head, after forming a silicon oxide film as a first insulating layer on the electrode substrate, boric acid, phosphorus, arsenic, or nitrogen is implanted into the first insulating layer to a desired depth. And forming a second insulating layer in the middle of the first insulating layer to form an insulating layer having a three-layer structure.