JP2000343714A - Quartz hole processing method and production of ink-jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive and highly accurate quartz hole processing method. SOLUTION: A quartz hole processing method for forming a predetermined hole in a quartz substrate 100 is provided. A mask 102 comprising an opening part 110 of a predetermined pattern is formed on the quartz substrate 100 surface in the Z surface direction. By forming a tip hole 111 in the mask opening part 110, and anisotropically etching the quartz substrate 100 with the tip hole 111 formed therein, a highly accurate hole can be produced inexpensively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a fine hole in a crystal, and more particularly to a method for processing a crystal hole capable of processing a hole with high accuracy.

[0002]

2. Description of the Related Art Conventionally, a silicon single crystal substrate has been used to manufacture an ink jet recording head.
A pressure chamber substrate was manufactured by forming a mask on a silicon single crystal substrate and etching and opening a cavity for filling ink. On one surface of the pressure chamber substrate, a vibration plate and a piezoelectric element were provided, and on the other surface, a nozzle plate having a nozzle opened was bonded.

[0003] Since silicon has anisotropy with respect to etching, a silicon single crystal substrate having a (110) plane orientation has been used to form an appropriate cavity.

[0004]

However, (11)
0) Since a silicon single crystal substrate with a plane orientation is much more expensive than a mass-produced substrate with a (100) plane for semiconductor production, an ink jet recording head that is inexpensive as long as a silicon single crystal substrate is used is manufactured. It was difficult to do.

[0005] Silicon has poor resistance to alkali.
When an ink jet recording head is used as an industrial material discharging means, there is a disadvantage that an alkaline discharging material liquid cannot be used.

[0006] In view of the above disadvantages, it is a first object of the present invention to provide a crystal hole processing method capable of processing a highly accurate hole with an inexpensive material.

The second object of the present invention is to provide a method of manufacturing an ink jet recording head capable of manufacturing a high precision ink jet recording head using inexpensive materials.
Subject.

[0008]

The applicant of the present invention has adopted quartz as a material which is inexpensive and capable of processing fine holes.

Although quartz is inexpensive, a large amount of energy is wasted when all holes are machined with a laser or the like to transmit light. Further, the hole formed by a laser or the like has an unstable shape, and cannot be used for manufacturing a high-density mounting element such as an ink jet recording head.

Therefore, the invention for solving the first problem is as follows.
In a crystal hole processing method for forming a predetermined hole in a crystal substrate, a step of forming a mask having an opening of a predetermined pattern on the surface of the crystal substrate having a Z-plane orientation, and forming a front hole in the opening of the mask. A method of processing a crystal hole, comprising: a step of forming; and a step of anisotropically etching the crystal substrate on which the tip hole is formed.

The step of forming the leading hole is, for example, a step of forming the leading hole by any one of laser machining, electric discharge machining, drilling, blasting, and ultrasonic machining.

In the case of forming the above-mentioned hole by laser processing, it is preferable to form the above-mentioned hole by branching a laser beam by a phase grating or a prism. It is preferable that the phase grating is any one of a binary phase grating, a multi-level phase grating, and a continuous phase grating.

The step of forming the mask includes a step of forming a metal layer on a quartz substrate surface having a Z-plane orientation, a step of forming a resist having a predetermined pattern on the metal layer, and etching from the resist. Forming an opening in the metal layer. The step of forming the mask,
The method further includes a step of forming an adhesion layer before the step of forming the metal layer.

It is preferable that the method further comprises a step of selecting at least one of a plurality of phase gratings having different ways of branching the laser beam before the step of forming the leading hole in the opening of the mask. In this case, in the step of forming the pre-hole, the pre-hole is formed by branching the laser beam into the opening of the mask by the selected phase grating.

In the selecting step, it is preferable to select a phase grating in accordance with a distribution pattern of the tip holes to be formed.

According to a second aspect of the present invention, there is provided a method of manufacturing an ink jet recording head using the crystal hole processing method of the present invention, wherein a cavity for filling ink is formed by the crystal hole processing method. And a method for manufacturing an ink jet recording head.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial cross-sectional view of a main part of an ink jet recording head according to this embodiment.

The ink jet recording head 1 is shown in FIG.
As shown in FIG. 1, the pressure chamber substrate 10, the nozzle plate 20,
A vibration plate 30 and a piezoelectric element 40 are provided, and are housed in a housing (not shown).

The pressure chamber substrate 10 has a cavity (pressure chamber) 11 provided in the quartz substrate by the hole drilling method of the present invention. Each cavity 11 is formed in a space shape for storing ink or the like for ejection. Side walls 12 partition between the cavities 11. Each cavity 11 is supplied with ink from a reservoir (not shown). Ink is supplied to the reservoir from an ink tank opening 31 provided in the diaphragm 30.

The vibration plate 30 is attached to one surface of the pressure chamber substrate 10, and a piezoelectric element 40 is provided at a position corresponding to the cavity 11. As the diaphragm 30, an oxide film (silicon dioxide film) is suitable because it has elasticity, mechanical strength and insulating properties.

The piezoelectric element 40 has a structure in which a piezoelectric thin film 402 is sandwiched between a lower electrode 401 and an upper electrode 403, as described later. The lower electrode 401 and the upper electrode 403 face each other, and an electromechanical conversion action can be generated in the piezoelectric thin film 402 by applying a voltage between the two electrodes.

The nozzle plate 20 is provided on the surface of the pressure chamber substrate 10 facing the vibration plate 30. In the nozzle plate 20, nozzles 21 are arranged at positions corresponding to the cavities 11, respectively.

The structure of the above-mentioned ink jet recording head is a piezo-jet type structure using a piezoelectric element as a driving element. A pressure chamber substrate manufactured by a processing method may be used.

In the structure of the ink jet recording head 1, when a voltage is applied between the electrodes and the piezoelectric element 40 is distorted, the diaphragm 30 is deformed in response to the distortion. Due to the deformation, the ink in the pressure chamber 21 is applied with pressure and is ejected from the nozzle 11.

FIG. 8 is a perspective view of a printer provided with the ink jet recording head 1 as an ink discharging means. This printer is, as shown in FIG.
, A tray 3 and a discharge port 4 are provided. Inside the main body 2, the ink jet recording head 1 of the present invention is incorporated. The main body 2 has an ink jet recording head 1 arranged so that a reciprocating operation can be performed so as to cross over the paper 5 supplied from the tray 3 by a paper supply mechanism (not shown). The discharge port 4 is an outlet from which the paper 5 on which printing has been completed can be discharged. (Manufacturing Method) Next, a first embodiment of a method for manufacturing a piezoelectric element and an ink jet recording head according to the present invention will be described. 2A to 7, (a) is a perspective view of a substrate, and (b) is a cross-sectional view of a manufacturing process along the AA cross section of the perspective view. In these figures, in order to make the structure easy to see, the set of the piezoelectric element and the cavity is limited to only four and is schematically shown.

Metal layer forming step (FIG. 2): This step is a step of forming a metal layer for patterning a mask.

The quartz substrate 100 is formed by slicing an ingot of quartz, for example, to a thickness suitable for the pressure chamber substrate, for example, 100 μm, and adjusting its outer shape. Slicing is performed so that the substrate surface is the Z surface of quartz. The Z plane is the z axis of the crystal axis of quartz.
The plane perpendicular to the axis. This is because the present invention utilizes the fact that quartz has anisotropy in the xy-axis direction and the z-axis direction of the crystal axis with respect to etching.

An adhesion layer 101 is formed on the quartz substrate 100 sliced on the Z plane. The adhesion layer 101 is a layer for increasing the adhesion between the quartz substrate 100 and the metal layer 102. As a material of the adhesion layer 101, a material having good compatibility with an inorganic material such as chromium or titanium and a metal is used. As a method for forming the adhesion layer 101, for example, a sputtering method or various evaporation methods is applied. The thickness of the adhesion layer 101 is set to a level that can ensure the adhesion, for example, about 100 Å.

On the adhesion layer 101, a metal layer 102 is formed. The metal layer 102 is a layer used as a mask of quartz for wet etching, and may have any resistance to an etchant. For example, gold is used for the metal layer 102. The method for forming the metal layer 102 depends on the material, but a sputtering method or various vapor deposition methods can be applied. Metal layer 102
Is set to a thickness that can function as a mask, for example, about 2,000 Å.

Mask formation step (FIG. 3): This step is a step of forming a resist of a predetermined pattern on the metal layer and etching the resist to form an opening in the metal layer.

A commonly used resist material is used. A resist is applied on the metal layer 102 by an application method such as a spin coating method. Exposure and development are performed by applying photolithography. That is, the resist is exposed by covering it with an exposure mask patterned into the shape of an opening, and then developing with a developer to remove unnecessary resist.

Next, the metal layer 102 and the adhesion layer 101 are etched according to the resist pattern. For example, gold of the metal layer 102 is etched with a potassium iodide solution, and chromium of the adhesion layer 101 is etched with a ceric ammonium nitrate solution. After the etching, the resist is removed to expose the mask of the metal layer provided with the opening 110 as shown in FIG. The opening 110 is formed in a square shape having a width of about 70 μm and a length of about 1000 μm, for example.

In FIG. 3, only the openings 110 corresponding to the cavities 11 are patterned. However, actually, the portions corresponding to the ink supply ports and the reservoirs leading to the cavities are also patterned to form the openings. Is formed.

Pre-Hole Forming Step (FIG. 4): This step is a step of forming a pre-hole by a predetermined method in an opening formed in the metal layer.

The leading hole is a hole to be used as a hole for introducing an etching solution for wet etching in the next step. As a method of forming the leading hole, for example, any one of laser processing, electric discharge machining, drilling, blasting, and ultrasonic machining can be applied. The laser processing is a method of irradiating a laser beam to the opening 110 and melting and evaporating the quartz with the energy thereof to form the tip hole 111. In electric discharge machining, an electrode is placed at a short distance above the workpiece, a DC power supply is connected between the electrode and the workpiece, and a short arc discharge is repeated to configure the workpiece. This is a processing method in which the material to be removed is removed. Drilling is a processing method in which a leading hole 111 is physically formed in the opening 110 using a minute drilling needle. The blast processing method is generally a sand blast method, in which abrasive particles are sprayed at a high speed onto a processing portion to physically cut the quartz. The ultrasonic processing method is a processing method in which a processing tool provided with ultrasonic vibration is brought into contact with a workpiece to grind a material constituting the workpiece.

For example, when laser processing is applied, YAG is applied to a specific portion of the crystal substrate surface exposed from the opening 110.
(Yttrium Aluminum Garnet) Irradiate a laser 112 (oscillation wavelength 1.06 μm) to melt the quartz and blow it out to form a front hole 111. Due to the laser irradiation, the melt adheres to the side wall of the pre-hole 111 or unevenness occurs on the processed surface. However, since all are removed by wet etching in the subsequent step, no inconvenience occurs.

The diameter of the leading hole 11 may be smaller than that of the opening 110, as long as it can serve as a hole for introducing an etching solution. Since the tip hole 111 is laser-processed with a minimum diameter, it is possible to reduce the energy usage fee.

In the case of forming a pre-hole by laser processing, a plurality of pre-holes can be formed with high accuracy by using a phase grating or a prism.

FIG. 9 is a conceptual diagram for explaining a method of applying laser processing using a phase grating. A laser beam 502 emitted from a laser light source 501 is expanded or reduced to a predetermined beam diameter by a beam expander 503 serving as a beam diameter adjusting unit, and its traveling direction is changed by a reflection mirror 504 to irradiate a phase grating 505. Is done. The laser beam 502 split by the phase grating 505 is condensed for each phase by the condensing lens 506, and then is irradiated to a specific portion of the quartz substrate to form a hole.

The phase grating 505 is a phase grating having a characteristic of changing the phase of incident light, and has a surface phase grating having unevenness (relief) on the surface and a refractive index inside the medium that changes periodically. Can be used.

The light transmitted through the phase grating travels in all directions. At that time, the light emitted from each grating interferes with each other, so that the light is increased or weakened depending on the direction. Specifically, light reinforces in a direction in which the optical path difference of light emitted from two adjacent gratings is an integral multiple of the light wavelength, and weakens in a direction that does not satisfy the condition. The phase grating can split light using this property.

Here, by changing the configuration of the phase grating (shape and spacing of the grooves), a distribution pattern of a plurality of front holes that can be formed simultaneously can be a desired distribution pattern. For example, by making the shape of the groove linear or concentric, the distribution can be made linear or curved. Also, by changing the interval between the grooves, the interval between the leading holes can be adjusted.

As the distribution pattern of the plurality of holes, for example, as shown in FIG.
The phase grating may be configured so that the front holes 111 are formed at the same time with respect to 10. As shown in FIG. The phase grating may be configured such that: FIG.
It is also conceivable to configure the phase grating such that a plurality of front holes 111 are simultaneously formed in a plurality of openings 110 as shown in FIG.

The uneven shape of the groove of the phase grating is shown in FIG.
The following can be considered. 11A shows a continuous shape, FIG. 11B shows a multivalued shape, and FIG. 11C shows a binary shape. The height difference between the concave portion and the convex portion is about several μm, and the height of each step of the multivalued shape is shown. The difference is less than 1 μm. Here, the quantum efficiency of each shape is 90 to 100%, 80 to 90%, and 70, respectively.
It is about 80%. The higher the quantum efficiency, the higher the intensity of the transmitted laser. Therefore, when using lasers of the same energy, the maximum number of holes that can be simultaneously formed increases in the order of continuous shape, multi-valued shape, and binary shape. On the other hand, from the viewpoint of ease of processing, the binary shape is most easily processed.

It is to be noted that the laser beam can be branched even if a prism is used instead of the phase grating, and a plurality of leading holes can be simultaneously formed in the same manner.

Anisotropic etching step (FIG. 5): This step is a step of anisotropically etching the quartz substrate on which the front holes are formed.

When anisotropic etching is performed on quartz,
The x-axis and y-axis directions of the crystal axis are selectively etched at a higher etching rate than the z-axis direction. The etching removes the melt adhered by the pre-hole processing and the unevenness of the processed surface. Etching proceeds along the opening 110 covered by the mask. Through this process, it is possible to form grooves with high precision and a high aspect ratio (ratio of depth to processing width) on a smooth processing surface.

For example, the quartz substrate 100 on which the mask of the metal layer 102 is formed is heated to a temperature of about 65.degree.
Immerse in the mixture of F. The wet crystal anisotropic etching is performed by this etchant, and a hole is formed in the shape of the cavity 11.

Vibration plate forming step (FIG. 6):
This is a step of forming a diaphragm provided with a piezoelectric element.

The piezoelectric element 40 is formed on the vibration plate 30 by sandwiching the piezoelectric thin film 402 between the lower electrode 401 and the upper electrode 403.

As the diaphragm 30, a silicon dioxide film or the like is suitable. The thickness of the diaphragm is about 1 μm. A lower electrode 401 is formed on the vibration plate using a conductive material such as platinum by a sputtering method or the like. A crystal film of the piezoelectric thin film 402 made of piezoelectric ceramics is formed thereon using a sol-gel method, a MOD method, a hydrothermal method, a sputtering method, a CVD method, or the like.
The thickness of the piezoelectric thin film 402 is in the range of 0.8 to 2 μm. After the piezoelectric thin film 402 is crystallized, the upper electrode 403 is formed using a conductive material such as platinum.

When the layer structure of the piezoelectric element 40 is completed in the above steps, the layer structure is etched into a shape corresponding to the cavity 11 to obtain the shape of the piezoelectric element 40.

Nozzle plate bonding step (FIG. 7): Finally, the nozzle plate 20 is bonded to the quartz substrate 100.

The nozzle plate 20 has a cavity 11
The nozzle 21 is provided according to the position. As the adhesive used for bonding, any adhesive such as an epoxy-based, urethane-based, or silicone-based adhesive can be used.

Through the steps described above, the main structure of the ink jet recording head 1 can be manufactured. If this is accommodated in a predetermined housing so that ink can be supplied, it can be operated as an inexpensive and highly alkali-resistant inkjet recording head.

Next, a description will be given of a second embodiment of the method of manufacturing the piezoelectric element and the ink jet recording head according to the present invention.

The present embodiment is similar to the first embodiment in that each step is provided, but differs from the first embodiment in that a phase grating selecting step is provided before the pre-hole forming step. Further, in the pre-hole forming step, a plurality of pre-holes are simultaneously formed by the branched light by branching the laser light by the phase grating.

Phase grating selecting step: This step is a step of selecting at least one of a plurality of phase gratings having different laser beam branching methods.

For example, in the mask forming step, the cavity,
It is assumed that an opening corresponding to an ink supply port and a reservoir that communicates with the cavity is formed. As shown in FIG. 12A, the openings 600 corresponding to the cavities, the openings 601 corresponding to the ink supply ports communicating with the cavities, and the openings 602 corresponding to the reservoirs have different opening patterns. In order to enhance the etching efficiency, it is desirable to make the distribution pattern of the front holes formed in the openings suitable for each of the opening patterns. FIG. 12B shows an example of a distribution pattern of the leading holes in each opening.

Therefore, in this step, a plurality of phase gratings having different laser beam branching methods are prepared, and the plurality of phase gratings are selected from the plurality of phase gratings so that the leading holes are appropriately distributed in accordance with each opening pattern. Choose one. In this case, in the pre-hole forming step, a plurality of pre-holes are formed simultaneously in the opening of the mask by branching the laser beam by the selected phase grating. The phase grating selecting step and the pre-hole forming step are repeated a predetermined number of times according to the number of opening patterns.

An example of an apparatus for selecting a plurality of phase gratings will be described with reference to FIG. In the figure,
A plurality (n: n is an integer) of transmission-type phase gratings 702n (7021, 7022, 702) are provided on the disk 701.
, 702n-1, 702n) are formed. The disk 701 is connected to the motor 703 and rotates. Here, the disk is rotated according to the opening pattern to be formed, and a phase grating 702i (1 ≦ i ≦ n) that can provide an appropriate distribution pattern of the leading holes is selected. For example, when the phase grating 7021 is selected and irradiated with the laser beam 704, the laser beam 705 is branched into a predetermined pattern by the phase grating 7021. Next, the light is made parallel by the condensing lens 706 and irradiated onto the workpiece 707 to form a tip hole having a predetermined distribution pattern. Then, disk 7
By rotating 01, another phase grating is moved to a predetermined position and selected, and a tip hole having a different distribution pattern is formed in another region of the workpiece 707. By repeating these operations, a processing pattern having a complicated shape can be formed on the workpiece 707.

According to the present embodiment, since quartz is used as the substrate material, it is possible to manufacture the element at a much lower cost (for example, about 1/5) than in the case of manufacturing the same shape using silicon. It is.

According to the present embodiment, since quartz is used as the substrate material, it has alkali resistance compared to silicon. Therefore, it is possible to discharge an alkaline material liquid which cannot be used conventionally as an industrial material from the ink jet recording head. It is possible.

According to the present embodiment, since the pre-drilling can be performed with a minimum amount of energy, it is possible to form fine holes without wasting energy.

According to the present embodiment, a plurality of pre-holes can be formed at the same time by a laser beam branched using a phase grating or a prism, so that the time required for forming the pre-holes can be reduced. Further, since the formation position of the leading hole is determined based on the configuration (shape and interval of the groove) of the phase grating or the prism, it is more accurate than the case where the laser optical system is mechanically moved to determine the forming position of the leading hole. The position can be determined. Furthermore, since a mechanism for mechanically moving is not required, a plurality of leading holes can be formed with a simple device configuration.

According to the present embodiment, by using a plurality of phase gratings or prisms, the distribution pattern of the leading holes can be changed according to the opening pattern, and a complex distribution pattern can be formed by combining the openings. .

According to the present embodiment, since the hole after processing is formed by wet anisotropic etching, precision is not required for the front hole, and the hole can be used regardless of the method of processing the front hole. is there. (Other Modifications) The present invention can be variously modified and applied irrespective of the above embodiments. For example, the quartz substrate manufactured by the present invention is not limited to an ink jet recording head, and can be used for various elements. According to the present invention, since quartz is cheaper than silicon, it is possible to provide a substrate having high alkali resistance at low cost.

The structure of the ink jet recording head is not limited to the above-mentioned structure as long as it is a piezo jet ink jet system, and another structure may be used.

[0070]

According to the present invention, since anisotropic etching is performed by using an inexpensive material called quartz and utilizing the anisotropy of quartz, a highly accurate hole can be machined inexpensively. Is possible.

According to the present invention, a high-precision pressure chamber substrate is formed of an inexpensive material such as quartz, so that a high-precision ink jet recording head can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a main part of an ink jet recording head of the present invention.

FIG. 2 is a diagram illustrating a metal layer forming step. (A) is a perspective view. (B) is AA sectional drawing.

FIG. 3 is a diagram illustrating a mask forming step. (A) is a perspective view. (B) is AA sectional drawing.

FIG. 4 is a diagram illustrating a pre-hole forming step. (A) is a perspective view. (B) is AA sectional drawing.

FIG. 5 is a diagram illustrating a wet etching step.
(A) is a perspective view. (B) is AA sectional drawing.

FIG. 6 is a diagram illustrating a diaphragm forming step. (A) is a perspective view. (B) is AA sectional drawing.

FIG. 7 is a diagram illustrating a nozzle plate joining step.
(A) is a perspective view. (B) is AA sectional drawing.

FIG. 8 is a structural diagram of a printer.

FIG. 9 is a conceptual diagram for explaining a method of applying laser processing using a phase grating.

FIG. 10 is a diagram for explaining a distribution pattern of tip holes.

FIG. 11 is a diagram for explaining the uneven shape of a groove of a phase grating.

FIG. 12 is a diagram illustrating a case where there are a plurality of patterns of an opening.

FIG. 13 is a schematic diagram showing an example of an apparatus for selecting a plurality of phase gratings.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pressure chamber substrate 11 Cavity 12 Side wall 20 Nozzle plate 21 Nozzle 30 Vibrating plate 40 Piezoelectric element 100 Crystal substrate 101 Adhesion layer 102 Metal layer 110 Opening 111 Front hole 505, 7021-702n Phase grating

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) B41J 2/055 // B23K 101: 36

Claims (10)

[Claims] 1. A method for processing a crystal hole for forming a predetermined hole in a crystal substrate, comprising: forming a mask having a predetermined pattern of openings on a surface of the crystal substrate having a Z-plane orientation; A method of processing a crystal hole, comprising: a step of forming a front hole in a portion; and a step of anisotropically etching the crystal substrate on which the front hole is formed. 2. The quartz crystal according to claim 1, wherein the step of forming the front hole includes forming the front hole by any one of laser processing, electric discharge machining, drilling, blasting, and ultrasonic machining. Hole processing method. 3. The method according to claim 1, wherein the step of forming the front hole comprises forming the front hole by branching a laser beam using a phase grating or a prism. 4. A method of processing a crystal hole for forming a predetermined hole in a crystal substrate, comprising: forming a mask having an opening of a predetermined pattern on a surface of the crystal substrate having a Z-plane orientation; A step of selecting at least one of a plurality of different phase gratings; a step of branching a laser beam by the selected phase grating into an opening of the mask to form a leading hole; And a step of anisotropically etching the quartz substrate on which is formed. 5. The crystal hole drilling method according to claim 4, wherein said selecting step selects a phase grating in accordance with a distribution pattern of tip holes to be formed. 6. The method according to claim 3, wherein the phase grating is any one of a binary phase grating, a multi-level phase grating, and a continuous phase grating. 7. The method according to claim 4, wherein the plurality of phase gratings are provided on a rotatable board. 8. The step of forming the mask includes: forming a metal layer on a quartz substrate surface having a Z-plane orientation; forming a resist having a predetermined pattern on the metal layer; and etching from the resist. Forming a hole in the metal layer by performing the step of forming a hole. 9. The method according to claim 1, further comprising: 9. The crystal hole processing method according to claim 8, wherein the step of forming the mask further comprises the step of forming an adhesion layer before the step of forming the metal layer. 10. A method for manufacturing an ink jet recording head using the method for processing a crystal hole according to claim 1, wherein a cavity for filling ink by the method for processing a crystal hole is provided. A method for manufacturing an ink jet recording head, comprising a step of forming.