JP3387352B2 - Ink jet recording head, ink jet recording apparatus using the same, and method of manufacturing ink jet recording head - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head which uses a piezoelectric thin film as a drive source for ink ejection, and an ink jet printer, a facsimile machine or a word processor which is equipped with this ink jet recording head and is used as an output device of a personal computer. The present invention relates to an inkjet recording apparatus and a method for manufacturing an inkjet recording head. The invention particularly relates to improvements in electrode formation technology.

[0002]

2. Description of the Related Art There is a piezoelectric ink jet recording head using a piezoelectric element made of lead zirconate titanate as an electro-mechanical conversion element which is a driving source for ejecting liquid or ink. This printer head generally has a head base on which a large number of individual ink paths are formed, a diaphragm attached to the head base so as to cover all the individual ink paths, and a diaphragm corresponding to the individual ink paths. It is composed of a piezoelectric element adhered to each part. Then, by applying an electric field to the piezoelectric element to displace the piezoelectric element, the ink in the individual ink path is pushed out from the nozzle of the individual ink path.

As an example of this conventional technique, a special table 5-
There is one described in Japanese Patent No. 504740. Therefore, a method of manufacturing the ink jet recording head described in this conventional example will be described with reference to the drawings.

As shown in FIG. 35, a silicon oxide film SID is formed on a silicon substrate SI, and a conductive layer FMF, which is a thin film of platinum, aluminum or nickel, is formed as a lower electrode. Then, as shown in FIG. 36, a resist region DRS exposed by a photolithography method.
37 is formed on the conductive layer, and as shown in FIG. 37, the exposed resist DRS region is used as a mask to form the electrode pattern FM.
Form L.

Next, as shown in FIG. 38, lead zirconate titanate PE, which is a kind of piezoelectric thin film, is formed by the sol-gel method.
Z further formed, then lead zirconate titanate PE
Second metal thin film SMF as an upper electrode so as to cover Z
Is deposited, and a resist RS is formed so as to cover the second metal thin film SMF.

Next, the ultraviolet light LA is passed through the mask MSK.
The exposed resist region DRS is formed so that Y is irradiated to obtain the second electrode pattern.

Further, as shown in FIG. 39, after forming the second electrode pattern SML, a protective film PSV is deposited. Furthermore, as shown in FIG. 39, a resist is deposited on the second main surface of the silicon substrate, and then ultraviolet light LAY is irradiated through the mask MSK to expose the resist region as shown in FIG. Form DRS.

Next, as shown in FIG. 41, the resist is stripped so as to leave the exposed resist region DRS, the silicon substrate SI is anisotropically etched in a strong alkaline solution, and the exposed resist region RDS is removed. Peel off the
The ink chamber CAV is formed.

[0009]

However, in the above-described method of manufacturing the ink jet recording head, the first electrode pattern FML and the second electrode pattern SML and the ink chamber CAV are not displaced from each other accurately. There is no consideration for forming at the position. Therefore, in order to form the electrode pattern and the ink chamber by accurately aligning them, photolithography by a double-sided exposure device may be applied to the above-mentioned conventional example.

However, when the electrodes of the ink jet recording head are patterned by the photolithography method, there is a problem that the electrodes cause electrolytic corrosion due to the developing solution for developing the exposed resist, and the electrode patterns cannot be formed. is there.

That is, the first electrode pattern is platinum,
In the case where the second electrode pattern is formed of a different material, a positive type photolithography resist is selected from the viewpoint of low cost and good patterning accuracy for electrode patterning and electrode protection. In this case, since the developer for the positive resist is the alkaline electrolyte, a corrosion phenomenon occurs due to the difference in electrochemical potential between platinum and the second metal thin film.

For example, when the first electrode pattern LE is platinum and the second electrode pattern is aluminum, hydrogen gas is generated from platinum of the first electrode in the alkaline aqueous solution of the positive resist developer, The phenomenon that the aluminum of the second electrode melts or peels occurs. Due to this electrolytic corrosion phenomenon, there is a problem that an electrode pattern formation defect occurs in the ink jet recording head, and furthermore, a piezoelectric element cannot be formed.

Therefore, it is an object of the present invention to provide an ink jet recording head that does not have a defective electrode pattern formation caused by such an electrolytic corrosion phenomenon, and an ink jet recording apparatus including the same. And Further, another object of the present invention is to provide a method capable of producing the above without causing the above-mentioned electrolytic corrosion phenomenon.

On the other hand, in order to eject a large amount of ink from the recording head, it is desired that the diaphragm be largely displaced. Therefore, for example, the first metal thin film is a platinum thin film having a large Young's modulus, and the second metal thin film is a metal thin film having a small Young's modulus. Since the aluminum thin film has a very small Young's modulus, when a voltage is applied to the piezoelectric element device, the aluminum thin film is deformed more than twice as much as when both the first metal thin film and the second metal thin film are platinum.

However, when the electrochemical potential of the second metal thin film is lower than that of the first metal thin film, the above-mentioned electrolytic corrosion phenomenon may occur when patterning the second metal thin film by photolithography. However, there is a problem that a good pattern of the second metal thin film cannot be obtained.

Therefore, an object of the present invention is to provide an ink jet type recording head, an ink jet type recording apparatus and a manufacturing method thereof, which can achieve the above-mentioned object while achieving a large displacement of the diaphragm. And

[0017]

In order to achieve the above-mentioned object, the present inventor has conducted extensive studies and found that in the manufacturing process of an ink jet recording head, a positive electrode was formed for pattern formation of electrodes or protection thereof. Even if the electrode is exposed to a positive resist developing solution using a positive resist, the upper electrode and the lower electrode are made to have a composition that does not cause electrolytic corrosion, so that the upper electrode and the lower electrode are electrically connected. It was found that even if there is, it is possible to prevent defects from being formed on the electrodes as in the conventional case.

On the other hand, in the process of manufacturing the ink jet recording head, by keeping the upper electrode and the lower electrode in a non-conducting state, even if the electrode is exposed to the developer of the positive resist, the electrode is electrolytically corroded. Can be avoided, and the composition of the upper electrode and the lower electrode can be made as desired.
Further, by using a negative resist in place of the positive resist for pattern formation of the electrodes or protection thereof, electrolytic corrosion can be prevented and the composition of the electrodes can be made desired. it can.

The present invention is characterized by a novel ink jet recording head obtained on the basis of such knowledge and a manufacturing method thereof.

In the ink jet recording head according to the present invention, the piezoelectric element device is formed on the first main surface of the substrate,
An ink chamber is formed on the second main surface, and this piezoelectric element device is formed by sequentially stacking a first electrode, a piezoelectric thin film, and a second electrode, and the material of the first electrode. And the electrochemical potential of the material of the second electrode is the same. Preferably, the first electrode and the second electrode are made of the same material.

More preferably, both the first electrode and the second electrode are made of platinum. Further, the ink jet recording head according to the present invention has a piezoelectric element device formed on the first main surface of the substrate and an ink chamber formed on the second main surface. An electrode, a piezoelectric thin film, and a second electrode are sequentially laminated to form an electrochemical potential of the material of the first electrode and an electrochemical potential of the material of the second electrode. It is characterized in that it is in a range such that no electrolytic corrosion occurs between the two electrodes with respect to the resist developing solution used when forming at least one of the second electrodes. Preferably, the electrochemical potentials of the first and second electrodes are in a range that does not cause electrolytic corrosion with respect to the alkaline electrolyte used for developing the positive resist.

Furthermore, another ink jet recording head of the present invention comprises a piezoelectric element device formed on the first main surface of the substrate and an ink chamber formed on the second main surface. A first electrode, a piezoelectric thin film, and a second electrode are sequentially stacked, and the first electrode and the second electrode are formed of metals having different electrochemical potentials. In addition, at least one pattern of the first and second electrodes is formed by using a negative resist.

The method for manufacturing an ink jet recording head according to the present invention comprises a step of forming a piezoelectric element device on the first main surface of the substrate and a step of forming an ink chamber on the second main surface. Then, the piezoelectric element device is formed by sequentially laminating a first electrode, a piezoelectric thin film and a second electrode on the substrate, and these electrodes and the ink chamber are formed into a predetermined pattern by using a resist. In the method of manufacturing an inkjet recording head, the first electrode and the second electrode are formed of metals having different electrochemical potentials, and at least one of the first and second electrodes is formed. A negative resist is used for forming a pattern so that the first electrode and the second electrode are not directly exposed to a developer for a positive resist. Than it is.

Another method of manufacturing an ink jet recording head according to the present invention comprises forming a piezoelectric device on a first main surface of a substrate and forming an ink chamber on a second main surface of the substrate.
This piezoelectric device is formed by sequentially stacking a first electrode, a piezoelectric thin film and a second electrode on a substrate, and patterning at least one of these electrodes and an ink chamber with a photoresist. The first electrode and the second electrode are laminated on the substrate so as not to be electrically connected to each other during the patterning process. In a preferred embodiment, the second electrode may be formed smaller than the piezoelectric thin film.

Another method of manufacturing an ink jet recording head according to the present invention comprises a step of forming a piezoelectric element device on the first main surface of a substrate and a step of forming an ink chamber on the second main surface. The piezoelectric element device is formed by sequentially laminating a first electrode, a piezoelectric thin film and a second electrode on the substrate, and these electrodes and ink chambers are formed in a predetermined pattern by using a resist. It was done,
The first electrode and the second electrode are made of materials having the same electrochemical potential. Preferably, the first electrode and the second electrode are made of the same material. Further, preferably, both the first electrode and the second electrode are made of platinum.

According to one embodiment, the ink jet recording head of the present invention comprises a step of forming an oxide film on both surfaces of a silicon substrate and a first oxide film on the first main surface of the silicon substrate. A step of depositing a metal thin film, a step of depositing a piezoelectric thin film on the first metal thin film, and a second metal thin film made of the same material as the first metal thin film on the piezoelectric thin film A step of forming a positive resist film on the oxide film of the second main surface of the silicon substrate on which the first metal thin film is not formed, and a negative resist on the second metal thin film. The first mask and the first main surface of the silicon substrate face each other between the step of depositing a film and the aligned first mask for photolithography and second mask for photolithography. Install the silicon substrate so that A step of irradiating both surfaces of the silicon substrate with light so as to expose the patterns of the first mask and the second mask, and patterning by developing the exposed positive resist with an alkaline solvent. A step of developing the exposed negative resist with an organic solvent and patterning, a step of depositing a positive resist on the entire first main surface, and a step of forming a positive resist on the second main surface. A step of etching an oxide film with an acidic solution using the patterned positive resist as a mask, a step of peeling the positive resist deposited over the entire first main surface, and a step of removing the positive resist on the first main surface. The method is characterized by including the step of etching the formed second metal thin film using the patterned negative resist as a mask.

According to another embodiment, the method of manufacturing an ink jet recording head according to the present invention comprises the steps of forming an oxide film on both sides of a silicon substrate and oxidizing the first main surface of the silicon substrate. A step of depositing a first metal thin film on the film, a step of depositing a piezoelectric thin film on the first metal thin film, and a material different from the first metal thin film on the piezoelectric thin film Forming a second metal thin film of
A step of depositing a positive type resist film on the oxide film of the second main surface of the silicon substrate on which the first metal thin film is not formed, and a first negative type resist film on the second metal thin film Between the step of depositing and forming the first mask for photolithography and the second mask for photolithography that are aligned so that the first mask and the first main surface of the silicon substrate face each other. The step of placing the silicon substrate, the step of irradiating both surfaces of the silicon substrate with light so as to expose the patterns of the first mask and the second mask, and the exposed positive type photo Developing the resist with an alkaline solvent and patterning it; developing the exposed first negative type photoresist with an organic solvent and patterning it; A step of depositing a second negative type photoresist on the entire surface, and a step of etching the oxide film formed on the second main surface with an acidic solution using the patterned positive type photoresist as a mask And a step of peeling off the second negative type photoresist deposited on the entire first main surface, and the patterned second metal thin film formed on the first main surface. The method is characterized by including a step of etching using one negative type photoresist as a mask.

Further, the present invention is characterized by an ink jet recording head formed by the above-described method for manufacturing an ink jet recording head, and an ink jet recording apparatus equipped with the ink jet recording head.

[0029]

First, a first embodiment of the present invention will be described. FIG. 1 is a cross-sectional view showing a first stage of a manufacturing process of an ink jet recording head according to the present invention. Hereinafter, the structure of the ink jet recording head manufactured in accordance with the progress of the manufacturing process will be described.

First, as shown in FIG. 1, a silicon substrate S
I is oxidized in a gas containing oxygen at 1100 ° C. to form a silicon oxide film SID having a film thickness of 1 μm.

Next, a first metal thin film LE is formed on the first main surface of the silicon substrate by sputtering or vapor deposition, MO-C.
Adhesion is formed by the VD method. The material of the metal thin film is preferably a metal having low reactivity with the lead zirconate titanate thin film PEZ, and platinum, iridium, or an alloy thereof is preferable.

For example, platinum is deposited on the first metal thin film to a thickness of 700 nm by sputtering at a substrate heating temperature of 200 ° C. Next, lead zirconate titanate PEZ is applied to the first metal thin film LE by a sputtering method, a sol-gel method, or a vapor deposition method at a thickness of 0.5 to 5 μm. Deposit on top.

The silicon substrate on which lead zirconate titanate PEZ is formed is polycrystallized by the RTA (rapid thermal annealing) method at 900 ° C. or the annealing treatment at 700 ° C. in a diffusion furnace.

Further, a second metal thin film TE is deposited on the annealed lead zirconate titanate PEZ. The metal thin film TE is preferably made of a material having the same electrochemical potential as the first metal thin film in order to prevent electrolytic corrosion in the photolithography process. For example, the first metal thin film and the second metal thin film may be platinum of the same material. A cross-sectional view of the substrate after the above series of steps is shown in FIG.

Next, as shown in FIG. 2, a negative type photoresist NR is formed in a thickness of 2 μm on the first main surface of the silicon substrate after the step shown in FIG. 1 by a spin coater method. Then, on the second main surface of the silicon substrate,
A positive type photoresist PR is formed with a thickness of 1 μm by a spin coater method. After forming each photoresist, an annealing treatment is performed at 140 ° C. for 30 minutes.

Next, alignment is performed between the negative mask NM for exposing the negative photoresist NR and the positive mask PM for exposing the positive resist PR, and the negative mask NM and the positive mask PM are aligned. In between, the silicon substrate SI shown in FIG. 2 is inserted as shown in FIG.

Since the silicon substrate SI also has alignment marks for alignment, the negative mask NM.
Alternatively, accurate alignment can be performed between the positive mask PM and the silicon substrate SI.

Next, as shown in FIG. 4, a silicon substrate SI
UV light LAY is radiated from both sides to expose the positive resist PR and the negative resist NR formed on the silicon substrate. In FIG. 4, the photosensitive area of the negative resist is set to LN.
The photosensitive area of R and the positive resist is indicated by LPR.

Next, as shown in FIG. 5, the photosensitive region LPR of the positive resist is dissolved and removed by a developing solution which is an alkaline aqueous solution. Next, as shown in FIG. 6, it is dissolved and removed with a developing solution which is an organic solvent so as to leave the photosensitive region LNR of the negative resist.

Next, as shown in FIG. 7, a positive resist PR having a thickness of 1 μm is deposited on the first main surface of the silicon substrate SI so as to cover the negative resist region LNR irradiated with light. Further, the silicon oxide film SID exposed on the second main surface of the silicon substrate SI is removed by etching with an aqueous solution containing hydrofluoric acid as a main component to expose the silicon surface CES on the second main surface of the silicon substrate.

Next, both surfaces of the first main surface and the second main surface of the silicon substrate are irradiated with light to expose the positive resist PR, and the positive resist PR is dissolved and removed by a developing solution which is an alkaline aqueous solution. In the case of a positive resist, it can be easily dissolved and removed by a developer by irradiating it with ultraviolet light.

When the first metal thin film and the second metal thin film are made of the same material or have the same electrochemical potential, even if the positive resist is stripped with a developing solution which is an alkaline aqueous solution, there is a problem of electrolytic corrosion. Does not occur. As shown in FIG.
The exposed negative resist region LNR is on the first main surface of the silicon substrate SI, and the second main surface of the silicon substrate SI is
The patterned silicon oxide film ISD is exposed.

Next, as shown in FIG. 9, the high energy particles HEP are applied to the first main surface of the silicon substrate to etch and remove the second metal thin film using the negative resist region LNR as a mask. Further, high energy particles are continuously irradiated and etched to form a patterned piezoelectric thin film EPZ. For example, this high energy particle HEP is an argon ion or an algin atom accelerated by a voltage of 400V.

By this step, as shown in FIG. 10, the patterned piezoelectric thin film EPZ and the patterned second metal thin film EAE are formed.

Next, as shown in FIG. 11, the negative resist region LNR irradiated with ultraviolet light is removed by ashing in oxygen plasma generated by microwaves at an output of 250 W, an oxygen flow rate of 100 sccm, and a time of 10 minutes. hand,
The surface of the patterned second metal thin film EAE is exposed.

Next, as shown in FIG. 12, an alkaline solution is applied to the entire first main surface of the silicon substrate so as to cover the patterned piezoelectric thin film EPZ and the patterned second metal thin film EAE. A protective film PFM that is not corroded is deposited. This protective film is an organic thin film containing fluorine and having a thickness of 5 μm.

Next, as shown in FIG. 13, a protective film PFM is formed.
The silicon substrate on which is deposited is dipped in an alkaline aqueous solution capable of being selectively etched with respect to the crystal orientation plane of silicon, and the exposed silicon on the second main surface is removed from the first main surface of the silicon substrate SI. The ink chamber CAV is formed by etching until the surface-side silicon oxide film SID is exposed.
This alkaline aqueous solution has, for example, a concentration of 10 at a temperature of 80 ° C.
% Potassium hydroxide aqueous solution.

Then, as shown in FIG. 14, a protective film PF is formed.
By peeling and removing M in oxygen plasma, a substrate for an inkjet recording head using the patterned piezoelectric thin film EPZ is formed.

Further, as shown in FIG. 15, an ink jet recording head is formed by adhering a nozzle plate NP having an ink ejection port NH so as to cover the ink chamber.

Next, a second embodiment of the present invention will be described. Similar to FIG. 1, a silicon oxide film SID is formed on the silicon substrate SI as shown in FIG. Further, a first metal thin film LE is deposited and formed on the first main surface of the silicon substrate. Next, lead zirconate titanate PEZ is deposited on the first metal thin film LE. Further, a second metal thin film TE is deposited on the lead zirconate titanate PEZ. As this second metal thin film, for example, 10
Aluminum thin film with a thickness of 0 nm to 500 nm
A film is formed by a sputtering method at a heating temperature of ° C.

To be precise, as shown in FIG. 16, the second metal thin film TE is in contact with the first metal thin film at its peripheral portion and both are in a conductive state. This is the same in the case of FIG. 1, but it is omitted in FIG. As described above, in the case of FIG. 1, even if the first metal thin film and the second metal thin film are in the conductive state with each other, both are formed of the same platinum, so that the ink jet recording head is The problem of electrolytic corrosion between electrodes does not occur even when immersed in an alkaline aqueous solution which is a developing solution for a positive resist.

Next, as shown in FIG. 17, a negative type photoresist NR having a film thickness of 2 μm is formed so as to cover the aluminum thin film TE which is the second metal thin film from above. Further, a positive type photoresist PR is similarly formed on the silicon oxide film SID on the second main surface of the silicon substrate.
It is formed to a thickness of μm. After forming each photoresist film, an annealing process is performed.

Next, as shown in FIG. 18, a negative mask NM for exposing the negative type photoresist NR.
Positioning is carried out between the positive mask PM for exposing the positive type photoresist PR and the film-formed silicon substrate SI is inserted between the negative mask NM and the positive mask PM.

Next, as shown in FIG. 19, a silicon substrate S
UV light LAY is irradiated from both sides of I to expose the positive type photoresist PR and the negative type photoresist NR formed on the silicon substrate. In FIG. 19, the photosensitive region of the negative type photoresist is LNR,
The photosensitive area of the positive type photoresist is indicated by LPR.

Next, as shown in FIG. 20, the photosensitive region LPR of the positive type photoresist is dissolved and removed by a developing solution which is an alkaline aqueous solution.

Next, as shown in FIG. 21, the negative type photoresist is dissolved and removed by a developing solution which is an organic solvent so as to leave the photosensitive region LNR.

In order to use an organic solvent for developing a photoresist on an aluminum thin film, which is a second metal thin film having electrochemical properties less base than platinum, which is a first metal thin film, as shown in this embodiment. Even if the first metal thin film and the second metal thin film are in a conductive state, the pattern of the second metal thin film can be formed without causing electrolytic corrosion.

Next, as shown in FIG. 22, a second negative type photoresist S having a thickness of 1 μm is formed so as to cover the negative type photoresist region LNR irradiated with light.
The NR is deposited on the first main surface of the silicon substrate SI without irradiating it with ultraviolet light. Further, the silicon oxide film SID exposed on the second main surface of the silicon substrate SI is removed by etching with an aqueous solution containing hydrofluoric acid as a main component to expose the silicon surface CES on the second main surface of the silicon substrate. As described above, since the negative type photoresist is deposited on the entire surface of the first main surface, even if the silicon oxide film on the second main surface is etched with hydrofluoric acid which is a strong acid, No damage such as peeling occurs on the thin film on the first main surface.

Next, as shown in FIG. 23, the second principal surface is irradiated with ultraviolet light to expose the positive type photoresist PR, and as shown in FIG. 24, a positive type photo resist is developed with a developing solution which is an alkaline aqueous solution. Dissolve and remove the resist. In the case of a positive type photoresist, it can be easily dissolved and removed by a developing solution by irradiating it with ultraviolet light. This developing solution is an inorganic alkaline solution or an organic alkaline solution, but a negative type photoresist is formed on the first main surface as a protective film SNR so as to cover the periphery of the second electrode thin film TE as well. Therefore, the thin film on the first main surface does not change.

Next, as shown in FIG. 25, the second negative type photoresist SNR formed on the first main surface of the silicon substrate is stripped with a developing solution of an organic solution.

A piezoelectric thin film is formed on the first metal thin film by a sol-gel method or a sputtering method, and at least one kind of metal having a standard redox potential lower than that of the first metal thin film is formed on the piezoelectric thin film. When the second metal thin film containing is formed, the coating on the substrate end of the piezoelectric thin film is not generally perfect.
The first metal thin film and the second metal thin film are shown in FIG.
Then contact as described above.

Suppose that a first metal thin film and a second metal thin film containing at least one kind of metal having a standard redox potential lower than that of the first metal thin film are formed, and the silicon oxide film on the second main surface is covered with a thin film. When the protective film for hydrofluoric acid of the piezoelectric element is a positive type photoresist when patterning with an acid, the developing solution for removing the positive type photoresist is, for example, sodium hydrogen phosphate 4%, silicic acid. Since it is an inorganic electrolyte containing 7% sodium,
When the first electrode and the second electrode are in a conductive state, a battery is formed by this electrolytic solution, and either the first metal thin film or the second metal thin film is formed due to the difference in electrochemical potential or redox potential. An electro-corrosion phenomenon occurs in which the ore is peeled from the substrate or is dissolved in the electrolytic solution.

Further, even if the developing solution which is the electrolytic solution is not used and the peeling is carried out by the oxygen plasma, the reaction of the negative type photoresist for the second electrode pattern and the positive type photoresist serving as the protective film with respect to the oxygen plasma. Since the speeds are almost the same, it is very difficult to selectively remove the positive type photoresist, which is the protective film. On the other hand, the negative type photoresist stripping solution is an organic solvent and there is no risk of electrolytic corrosion.

For this reason, a negative type photoresist is suitable for the protective film SNR for the piezoelectric element when etching the silicon oxide film on the second main surface with hydrofluoric acid.
As a result, the electrolytic corrosion phenomenon does not occur in the metal thin films sandwiching the piezoelectric thin film.

As shown in FIG. 26, the exposed negative type photoresist region LNR is formed on the first main surface of the silicon substrate SI, and the patterned silicon oxide film ISD is formed on the second main surface of the silicon substrate SI. Is exposed.

Next, as shown in FIG. 27, the high-energy particles HEP are applied to the first main surface of the silicon substrate to etch and remove the second metal thin film by using the negative type photoresist region LNR as a mask. . Further, high energy particles are continuously irradiated and etched to form a patterned piezoelectric thin film EPZ.

By this step, as shown in FIG. 28, the patterned piezoelectric thin film EPZ and the patterned second metal thin film EAE are formed.

Next, as shown in FIG. 29, the negative type photoresist region LNR irradiated with ultraviolet light is exposed to, for example, an output of 2 in an oxygen plasma generated by microwaves.
Second metal thin film EA patterned by ashing removal at 50 W, oxygen flow rate of 250 sccm, and time of 15 minutes
The surface of E is exposed.

Next, as shown in FIG. 30, an alkaline solution is applied to the entire first main surface of the silicon substrate so as to cover the patterned piezoelectric thin film EPZ and the patterned second metal thin film EAE. A protective film PFM that is not corroded is deposited. The protective film is a fluororesin having a thickness of 5 μm.

Next, as shown in FIG. 31, a protective film PFM is formed.
The silicon substrate on which is deposited is dipped in an alkaline aqueous solution capable of anisotropically etching with respect to the crystal orientation plane of silicon, and the exposed silicon of the second main surface is removed from the silicon substrate SI. The ink chamber CAV is formed by etching until the silicon oxide film SID on the main surface side is exposed.

Subsequently, as shown in FIG. 32, the protective film PF
By peeling and removing M in oxygen plasma, a substrate for an inkjet recording head using the patterned piezoelectric thin film PZE is formed.

Further, as shown in FIG. 33, the ink chamber C
An ink jet recording head is formed by adhering the nozzle plate NP formed with the ink ejection openings NH so as to cover the AV.

Although the second metal thin film is an aluminum thin film in the above embodiment, the second metal thin film is not limited to aluminum. For example, a metal thin film contacting lead zirconate titanate has a thickness of
The present invention can be applied to a two-layer thin film of 0 nm titanium and a 200 nm thick gold thin film continuously formed on the titanium. Since the gold thin film is a soft material having a very small Young's modulus, the actuator can be sufficiently displaced. Furthermore, since the gold thin film has a low specific resistance, it is possible to transmit a signal from the driver circuit with almost no distortion. Further, unlike the aluminum, the gold thin film does not oxidize in the atmosphere, so that contact resistance does not occur during connection such as soldering of the driver IC, so that driver signal distortion does not occur.

Next, a third embodiment of the present invention will be described. In this embodiment, in order to prevent the first electrode from conducting to the second electrode in the process of manufacturing the ink jet recording head, the second electrode TE is placed on the first electrode as shown in FIG. The lead zirconate titanate formed PEZ is formed smaller than the piezoelectric body so as to be inside the peripheral portion. After FIG. 34, the ink jet recording head is formed based on the above-described first embodiment. In this embodiment, since the first electrode is not electrically connected to the second electrode during the manufacturing process of the ink jet recording head, the first electrode and the first electrode are not patterned when the ink jet recording head is patterned. Even if the second electrode is exposed to the developer of the positive type resist, the electrolytic corrosion of the electrode can be avoided.

In the above description, the problem of electrolytic corrosion between electrodes occurs when the first electrode and the second electrode are exposed to the electrolytic solution which is the developing solution for the positive resist. It was
However, this problem of electrolytic corrosion also occurs when the developing solution for the negative resist is an electrolytic solution. Therefore, the problem of electrolytic corrosion of the present invention occurs when the resist is developed using the electrolytic solution regardless of whether it is a positive type resist or a negative type resist. In the case of a positive resist, the electrolytic solution of the current resist is a mixed solution of sodium silicate and sodium hydrogen phosphate, and in the case of a negative resist, an electrolytic solution such as a mixed solution of xylene and ethylbenzene. Not an organic solvent. Therefore, the present invention is understood as not exposing the electrodes to the resist developer which is the electrolyte.

[0076]

According to the ink jet recording head of the present invention, since the first metal thin film and the second metal thin film are the same, peeling or dissolution of the metal thin film due to electrolytic corrosion in the manufacturing process of the ink jet recording head. Does not cause damage.

That is, if the electrochemical potentials of the materials of the first metal thin film and the second metal thin film of the piezoelectric element device are the same in the double-sided simultaneous exposure, the piezoelectric element device is damaged by peeling or melting of the metal thin film. It is possible to form an ink jet type recording head substrate without generation of

Further, since no positive type photoresist is used in the photolithography process of the first main surface of the substrate, damage such as peeling or melting of the metal thin film due to electrolytic corrosion does not occur in the manufacturing process of the ink jet recording head. .

Therefore, even if the materials of the first metal thin film and the second metal thin film of the piezoelectric element device are different from each other by the simultaneous exposure on both sides, the piezoelectric element device is not damaged and the ink jet type recording head substrate can be formed.

Further, even if the electrochemical potentials of the materials of the first metal thin film and the second metal thin film of the piezoelectric element device are different by the simultaneous exposure on both sides, the piezoelectric element device is not damaged by peeling or melting of the metal thin film. An ink jet type recording head substrate can be formed without generation.

Further, by using the platinum thin film having a large Young's modulus as the first metal thin film which also functions as the diaphragm and the aluminum thin film having a small Young's modulus as the second metal thin film, the vibration of the diaphragm is more than double that of the conventional one. Since the displacement is generated, it is possible to eject ink droplets more than twice as large as the conventional one, so that a printer using the ink jet recording head of the present invention can realize very clear print quality.

[Brief description of drawings]

FIG. 1 is a sectional view of a step of manufacturing an inkjet recording head according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the next stage of FIG.

FIG. 3 is a cross-sectional view of the next stage of FIG.

FIG. 4 is a cross-sectional view of the next stage of FIG.

FIG. 5 is a cross-sectional view of the next stage of FIG.

6 is a cross-sectional view of the next stage of FIG.

FIG. 7 is a cross-sectional view of the next stage of FIG.

FIG. 8 is a cross-sectional view of the next stage in FIG.

FIG. 9 is a cross-sectional view of the next stage of FIG.

10 is a cross-sectional view of the next stage of FIG.

11 is a cross-sectional view of the next stage of FIG.

FIG. 12 is a cross-sectional view of the next stage of FIG. 11.

FIG. 13 is a cross-sectional view of the next stage in FIG.

FIG. 14 is a cross-sectional view of the next stage of FIG.

FIG. 15 is a cross-sectional view of the next stage of FIG.

FIG. 16 is a cross-sectional view of one stage of an inkjet recording head manufacturing process according to the second embodiment of the present invention.

FIG. 17 is a cross-sectional view of the next stage of FIG. 16.

FIG. 18 is a cross-sectional view of the next stage of FIG.

FIG. 19 is a cross-sectional view of the next stage of FIG.

20 is a cross-sectional view of the next stage of FIG. 19.

FIG. 21 is a cross-sectional view of the next stage of FIG. 20.

FIG. 22 is a cross-sectional view of the next stage of FIG. 21.

FIG. 23 is a cross-sectional view of the next stage of FIG. 22.

FIG. 24 is a cross-sectional view of the next stage of FIG. 23.

FIG. 25 is a cross-sectional view of the next stage of FIG. 24.

FIG. 26 is a cross-sectional view of the next stage of FIG. 25.

FIG. 27 is a cross-sectional view of the next stage of FIG. 26.

FIG. 28 is a cross-sectional view of the next stage of FIG. 27.

FIG. 29 is a cross-sectional view of the next stage of FIG. 28.

FIG. 30 is a cross-sectional view of the next stage of FIG. 29.

FIG. 31 is a cross-sectional view of the next stage of FIG. 30.

32 is a cross-sectional view of the next stage of FIG. 31. FIG.

FIG. 33 is a cross-sectional view of the next stage of FIG. 32.

FIG. 34 is a plan view showing a first stage of the method for manufacturing the ink jet recording head according to the third embodiment of the present invention.

FIG. 35 is a sectional view of a first stage of a conventional inkjet recording head manufacturing process.

FIG. 36 is a cross-sectional view of the next stage of FIG. 35.

FIG. 37 is a cross-sectional view of the next stage of FIG. 36.

38 is a cross-sectional view of the next stage of FIG. 37. FIG.

FIG. 39 is a cross-sectional view of the next stage of FIG. 38.

FIG. 40 is a cross-sectional view of the next stage of FIG. 39.

41 is a cross-sectional view of the next stage of FIG. 40.

[Explanation of symbols]

CAV ... Ink chamber CES ... Silicon surface EAE of the second main surface ... Patterned second metal thin film EPR ... Patterned positive type photoresist EPZ ... Patterned piezoelectric thin film FMF ... Conductive layer FML ... Electrode pattern HEP High energy particles ISD ... Patterned silicon oxide film LAY ... Light, ultraviolet light LE ... First metal thin film, first electrode, lower electrode LNR ... Photosensitive negative type photoresist region LPR ... Photosensitive positive type photoresist Region MSK ... Mask NH ... Ink ejection port NM ... Negative type photoresist mask NP ... Nozzle plate NR ... Negative type photoresist PEZ ... Lead zirconate titanate thin film PFM ... Protective film PM ... Positive type photoresist mask PR ... Positive type Photo register Stroke PSV ... Protective film RS ... Resist SI ... Silicon substrate SID ... Silicon oxide film SMF ... Second metal thin film SML ... Second electrode pattern SNR ... Second negative type photoresist TE ... Second metal thin film, second Electrode, upper electrode

Claims (4)

(57) [Claims] 1. A step of forming an oxide film on both surfaces of a silicon substrate, a step of depositing a first metal thin film on the oxide film of a first main surface of the silicon substrate, and the first metal. A step of depositing a piezoelectric thin film on the thin film, a step of forming a second metal thin film of the same material as the first metal thin film on the piezoelectric thin film, and a first metal thin film of the silicon substrate A step of depositing a positive resist film on the oxide film on the second main surface that has not been formed, a step of depositing a negative resist film on the second metal thin film, and aligned photolithography A first mask for photolithography and a second mask for photolithography so that the first mask and the first main surface of the silicon substrate face each other; and The mask and the pattern of the second mask As described above, the step of irradiating the both surfaces of the silicon substrate with light, the step of developing and patterning the exposed positive resist with an alkaline solvent, and the step of developing and patterning the exposed negative resist with an organic solvent A step of depositing a positive resist on the entire surface of the first main surface, and a step of etching the oxide film formed on the second main surface with an acidic solution using the patterned positive resist as a mask And a step of peeling off the positive resist deposited over the entire first main surface, and using the patterned negative resist as a mask for the second metal thin film formed on the first main surface. A method for manufacturing an ink jet recording head having a step of etching. 2. A step of forming an oxide film on both surfaces of a silicon substrate, a step of depositing a first metal thin film on the oxide film of a first main surface of the silicon substrate, and the first metal. A step of depositing a piezoelectric thin film on the thin film, a step of forming a second metal thin film of a material different from the first metal thin film on the piezoelectric thin film, and a first metal thin film of the silicon substrate A step of depositing a positive type resist film on the oxide film of the second main surface that has not been formed, a step of depositing a first negative type resist film on the second metal thin film, and a position A step of placing the silicon substrate such that the first mask and the first main surface of the silicon substrate face each other between the aligned first mask for photolithography and the second mask for photolithography. And the first mask and the second Irradiating both surfaces of the silicon substrate with light so as to expose the mask pattern, the step of developing the exposed positive type photoresist with an alkaline solvent and patterning, and exposing the exposed first type photoresist. A step of developing and patterning a negative type photoresist with an organic solvent, and a step of depositing a second negative type photoresist on the entire first main surface,
A step of etching the oxide film formed on the second main surface with an acidic solution using the patterned positive type photoresist as a mask; Of the negative type photoresist, and a step of etching the second metal thin film formed on the first main surface using the patterned first negative type photoresist as a mask. And a method for manufacturing an ink jet recording head. 3. An ink jet recording head formed by the method for manufacturing an ink jet recording head according to claim 1. 4. An ink jet recording apparatus comprising the ink jet recording head according to claim 3.