JP7119943B2 - Nozzle plate manufacturing method and inkjet head manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a nozzle plate and a method for manufacturing an inkjet head using the method. More specifically, the present invention relates to a nozzle plate capable of forming nozzle diameters with high dimensional accuracy and nozzle internal shapes with high accuracy. The present invention relates to a manufacturing method and a manufacturing method of an inkjet head having each step of manufacturing the nozzle plate.

Conventionally, in order to improve the ejection accuracy of an inkjet head that ejects ink from nozzles, there has been proposed a nozzle plate in which only the outlet vicinity of tapered nozzles is straightened. By forming the straight portion in the nozzle, the dimensional accuracy of the hole diameter during processing of the nozzle is stabilized, so that the effect of keeping the ink discharge amount from each nozzle constant can be expected.

A method for manufacturing such a nozzle plate is disclosed, for example, in Patent Document 1 and Patent Document 2.

Patent Document 1 discloses a method for manufacturing a funnel-shaped nozzle plate in which a tapered communication passage and a straight opening are formed in an SOI (Silicon On Insulator) substrate, which is a silicon wafer having a structure in which a silicon single crystal layer is formed on an oxide film. disclosed.

In the method described in Patent Document 1, an SOI substrate is used, and a BOX layer (thermal oxide film layer) is stopped by ICP deep etching to form a straight opening (also referred to as a nozzle straight portion) on the BOX layer side, Then, the straight opening is protected with an oxide film, and a tapered communication path (also called a tapered portion) is formed by, for example, wet anisotropic etching. In the method described in Patent Document 1, the nozzle straight portion at the time of injection is formed on the bottom surface of ICP deep excavation. Considering variations in etching in ICP processing, it is necessary to set the etching time longer to secure a process margin. In addition, the BOX layer is an insulator, and plasma notching is likely to occur at the bottom surface (near the BOX layer), and it is assumed that the nozzle diameter accuracy cannot be satisfied. Further, in the pattern of forming a tapered communication path after forming a straight opening, there is a problem that misalignment occurs at each center line.

Further, Patent Document 2 discloses a method of manufacturing a funnel-shaped nozzle plate in which a silicon substrate is used and tapered communication passages and straight openings are formed.

The method disclosed in Patent Document 2 is a method of forming a straight opening in the upper surface of a silicon substrate. Specifically, a silicon substrate is used, and a straight opening is first formed by ICP deep engraving and intermediate stopper processing. This is a method of forming a tapered communication path by anisotropic wet etching.

The method disclosed in Patent Document 2 eliminates the influence of notching and the like that tend to occur in the method described in Patent Document 1, and is expected to improve the nozzle diameter accuracy. Moreover, since pattern formation is performed only once, the problem of misalignment can also be solved.

However, in the method described in Patent Document 2, it is difficult to selectively anisotropically etch only the protective film on the bottom surface after forming the protective film inside the straight opening, resulting in variations in processing accuracy. I have concerns about that. In particular, since the reactive species of anisotropic etching tends to charge the edge portion and the insulating film, damage to the protective film at the edge portion of the opening and variations in the straight length of the bottom portion are likely to occur. In addition, in the method proposed in Patent Document 2, the etched region of the bottom surface of the straight processed portion is a closed system, so it is difficult to replace the etchant, and it is expected that the etching will take a long time. On the other hand, since etching progresses relatively quickly at the tip of the straight opening corresponding to the nozzle opening, the protective film tends to disappear, and variations in processing accuracy are also expected.

Therefore, there is a demand for the development of a nozzle plate manufacturing method that is capable of forming a tapered communication passage without misalignment on the central axis, suppressing variations in processing, and forming a straight opening with high precision, and which is excellent in mass productivity. ing.

Japanese Patent No. 5519263 JP 2011-37053 A

The present invention has been made in view of the above problems, and the problem to be solved is to form the dimensional accuracy of the nozzle diameter, and to form the tapered communication passage and the straight opening of the nozzle with high accuracy without variations in the central axis. It is another object of the present invention to provide a method for manufacturing a nozzle plate that can achieve a high degree of uniformity, and a method for manufacturing an inkjet head having each step of manufacturing the nozzle plate.

In order to solve the above problems, the inventors of the present invention, in the process of studying the causes of the above problems, have found a method for manufacturing a nozzle plate in which a tapered communication passage and a straight opening (nozzle hole) are simultaneously formed continuously by forming a single pattern. By adopting a formation pattern formed in such a manner that the tapered communication passage and the straight opening are formed, it is possible to eliminate the variation in the center axis. Furthermore, by adopting a method of forming the straight opening for forming the nozzle hole after forming the tapered communication passage by wet etching, it is possible to eliminate the shape defect of the nozzle tip due to wet etching, and achieve the desired tip shape. The present inventors have found that a nozzle having

That is, the above problems related to the present invention are solved by the following means.

1. A method for manufacturing a nozzle plate having at least a tapered communication passage and a straight opening forming a nozzle portion,
A method for manufacturing a nozzle plate, characterized by manufacturing a nozzle plate through at least steps 1 to 8 below.

Step 1: a step of preparing a single crystal silicon substrate having a (100) surface;
Step 2: a step of uniformly forming a mask layer on the surface of the single crystal silicon substrate;
Step 3: A step of forming an annular pattern, which will become a nozzle hole in the future, and a polygonal or circular pattern inside it, on the mask layer;
Step 4: A step of forming a resist layer on the annular pattern and penetrating or partly deep-etching the polygonal or circular pattern by dry etching;
Step 5: removing the resist layer formed on the annular pattern;
Step 6: A step of anisotropically wet-etching the single crystal silicon substrate to form the tapered communication path extending from the polygonal or circular pattern into an octahedral shape;
Step 7: A step of forming the straight opening that will be the tip of the nozzle hole by penetrating the annular pattern to the tapered communication path by deep etching by dry etching;
Step 8: A step of trimming the outside diameter to a predetermined size and chipping.

2. Item 1, characterized in that, after the step 7, there is a step of grinding and polishing the surface of the single crystal silicon substrate opposite to the surface on which the straight opening is provided, up to the center portion of the tapered communication path . A method for manufacturing the nozzle plate according to 1.

3. 3. The nozzle plate according to claim 1 or 2, wherein the angle (θ2) formed by the upper surface of the tip of the nozzle hole and the side surface of the straight opening is within the range of 70 to 90 degrees. manufacturing method.

4. 4. The method of manufacturing a nozzle plate according to any one of items 1 to 3, wherein surfaces of the tapered communication passage and the straight opening are covered with a protective film having ink resistance.

5. 5. The method of manufacturing a nozzle plate according to any one of items 1 to 4, wherein an ink-repellent layer is formed on the outermost surface.

6. A method for manufacturing an inkjet head, comprising steps 1 to 8 in the method for manufacturing a nozzle plate according to any one of items 1 to 5.

According to the above-described means, a method for manufacturing a nozzle plate that can form the dimensional accuracy of the nozzle diameter, the tapered communication passage and the straight opening of the nozzle with high accuracy without variations in the central axis, and the nozzle. It is possible to provide an inkjet head manufacturing method having each step of manufacturing a plate.

The technical features of the method for manufacturing a nozzle plate having the configuration defined by the present invention and the mechanism of its effects are as follows.

The technical feature of the method for manufacturing a nozzle plate of the present invention is characterized in that the tapered communication passage and the straight opening (nozzle hole) are continuously formed in this order by one pattern formation. By taking the pattern, it is possible to eliminate variations in the center axis between the tapered communication passage and the straight opening. Further, by adopting a method of forming a tapered communication path by wet etching and then forming a straight opening for forming a nozzle hole, the conventional method of forming a tapered communication path by wet etching after forming a nozzle hole is adopted. On the other hand, it is possible to eliminate the shape defects of the nozzle tip, such as the deviation of the tip diameter due to the undercut that occurs during wet etching and the variation in the wafer surface, and form the nozzle with the desired tip shape with high accuracy. can do.

FIG. 4 is a cross-sectional view showing an example of main forming steps in the manufacturing process of the nozzle plate of the present invention; FIG. 2 is a cross-sectional view (embodiment 1) showing a manufacturing step (part 1) in a typical method of manufacturing a nozzle plate according to the present invention; FIG. 2 is a cross-sectional view showing a manufacturing step (No. 2) in a typical method of manufacturing a nozzle plate according to the present invention (Embodiment 1); Top view in manufacturing step S-3 and manufacturing step S-6 shown in FIG. FIG. 5 is a cross-sectional view showing an example of the configuration of the nozzle plate of the present invention in which a protective film and an ink-repellent layer are formed (Embodiment 2). FIG. 11 is a cross-sectional view (Embodiment 3) showing another example (No. 1) of the manufacturing method of a typical nozzle plate of the present invention. FIG. 11 is a cross-sectional view (Embodiment 3) showing another example (No. 2) of the manufacturing method of a representative nozzle plate of the present invention. FIG. 4 is a diagram for explaining the angle of the tip of the nozzle hole and the angle of the taper communicating portion in the nozzle plate of the present invention; Sectional view showing an example of a configuration in which a communicating path plate is connected to a nozzle plate (Embodiment 4) FIG. 5 is a cross-sectional view showing an example of a configuration in which Ni electroforming is connected to a nozzle plate via a seed layer (Embodiment 5) Cross-sectional view showing an example of the configuration of an inkjet head

A method for manufacturing a nozzle plate according to the present invention is a method for manufacturing a nozzle plate having at least a tapered communication passage and a straight opening forming a nozzle portion, wherein the nozzle plate is manufactured through at least steps 1 to 8. It is characterized by manufacturing. This feature is a technical feature common to the inventions according to the following embodiments.

As an embodiment of the present invention, from the viewpoint of exhibiting the effect of the present invention, after the step 7, the surface of the single crystal silicon substrate opposite to the surface on which the straight opening is provided is the center of the tapered communication path . It is preferable to have a step of grinding and polishing up to the part.

Further, by setting the angle (θ2) between the upper surface of the tip of the nozzle hole and the side surface of the straight opening within the range of 70 to 90 degrees, more stable ink ejection performance can be ensured. point is preferable.

In addition, it is preferable to coat the surfaces of the tapered communication passage and the straight opening with a protective film having ink resistance in that corrosion due to ink can be prevented and a highly durable nozzle plate can be produced.

Forming an ink-repellent layer on the outermost surface can prevent ink mist from adhering to the nozzle plate surface during ink ejection, and can maintain ink ejection stability over a long period of time. point is preferable.

A method for manufacturing an inkjet head of the present invention is characterized by including each step in the method for manufacturing a nozzle plate of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The present invention, its constituent elements, and embodiments and modes for carrying out the present invention will be described in detail below. In addition, in the present application, "-" representing a numerical range is used in the sense that the numerical values described before and after it are included as a lower limit value and an upper limit value. Also, in the following description, the numerals in parentheses after each component represent the reference numerals of each component described in each drawing.

<<Manufacturing method of nozzle plate>>
A method for manufacturing a nozzle plate according to the present invention is a method for manufacturing a nozzle plate having at least a tapered communication passage and a straight opening forming a nozzle portion,
The nozzle plate is manufactured through at least the following steps 1 to 8.

Step 1: a step of preparing a single crystal silicon substrate having a (100) surface;
Step 2: a step of uniformly forming a mask layer on the surface of the single crystal silicon substrate;
Step 3: A step of forming an annular pattern that will become a nozzle hole in the future and a rectangular pattern inside it on the mask layer;
Step 4: A step of forming a resist layer on the annular pattern, and penetrating the rectangular pattern portion by dry etching, or deep etching a part of the rectangular pattern portion;
Step 5: removing the resist layer formed on the annular pattern;
Step 6: A step of anisotropically wet-etching the single crystal silicon substrate to form the tapered communication path extending from a rectangular pattern into an octahedral shape;
Step 7: A step of forming the straight opening that will be the tip of the nozzle hole by penetrating the annular pattern to the tapered communication path by deep etching by dry etching;
Step 8: A step of trimming the outside diameter to a predetermined size and chipping.

[Major Characteristics of Nozzle Plate Manufacturing Method]
The main feature of the method for manufacturing a nozzle plate of the present invention is that a single crystal silicon substrate is used, and in the first step, anisotropic wet etching is used to form tapered communication passages extending in an octahedral shape, followed by the second step. is characterized by forming a straight opening that will be the tip of the nozzle hole by deep excavation by dry etching, and this method of forming the nozzle part improves the dimensional accuracy of the nozzle diameter, the taper communication path of the nozzle, and the straight opening. It is possible to manufacture a nozzle plate having a high-precision structure with no variation in the center axis between the parts.

FIG. 1 is a schematic cross-sectional view showing a step of producing a tapered communicating passage and a straight opening, which is a major step in the manufacturing method of the nozzle plate of the present invention.

The manufacturing step shown in (a) of FIG. 1 is the step S-7 shown in FIG. The first mask layer (2) is formed on both sides of the silicon substrate (1), and the first mask layer (2) is formed on both sides of the silicon substrate (1). A second mask layer (3) and a resist layer 2 (7) are formed on the layer (2), and dry etching is applied to the polygonal or circular pattern ( 6B, deep trench forming part). (DE2) forms a deep trench path (8).

Next, the manufacturing step shown in FIG. 1(b) is anisotropic wet etching of the single crystal silicon substrate in step S-8 shown in FIG. Forming tapered communication passages extending from a rectangular or circular pattern into an octahedral shape”, etching the silicon substrate by anisotropic wet etching to form octahedral tapered communication passages (9). .

Next, the manufacturing step shown in (c) of FIG. 1 is the step S-9 shown in FIG. The nozzle hole forming portion (5B), which is an annular pattern, is deeply excavated by dry etching to form a straight opening serving as a nozzle hole. Form part (10).

After forming the tapered communication path in this way, the straight opening is formed consistently, thereby forming the center axis 1 (C1) shown in FIG. 1(a) and the center axis shown in FIG. 1(b). 2 (C2) and central axis 3 (C3) described in (c) of FIG. In addition, in this method, a tapered communicating passage is formed first, and then a straight opening is formed. Since the shape of the nozzle portion, which is a straight opening, is not damaged by etching or the like, the nozzle portion can be formed in a stable shape. be able to.

[Embodiment 1: Nozzle plate manufacturing method 1]
Next, a specific configuration of the nozzle plate manufacturing method of the present invention will be described with reference to the drawings.

2 and 3 are sectional views (Embodiment 1) showing a manufacturing step (No. 1) in a typical nozzle plate manufacturing method of the present invention.

(Step 1: Preparation of Single Crystal Silicon Substrate)
The step shown in step S-1 in FIG. 2 is “step 1: a step of preparing a single crystal silicon substrate having a (100) surface” defined in the present invention, and the surface of the substrate of the nozzle plate is This is a step of preparing a single crystal silicon substrate (1) having a (100) plane.

A single-crystal silicon substrate (1) having a (100) plane applicable to the present invention is a plate member made of silicon having a thickness of about 100 to 200 μm. By using the silicon substrate (1) as the base material of the nozzle substrate, the nozzle plate can be processed with high accuracy, and the nozzle plate can be formed with less positional errors and less variation in shape. The silicon substrate is preferably SOI (Silicon On Insulator), which is a silicon wafer having a structure in which a silicon single crystal layer is formed on an oxide film.

(Step 2: Formation of mask layer)
The step shown in step S-2 in FIG. 2 is "step 2: a step of uniformly forming a mask layer made of a mask material on the surface of the single crystal silicon substrate" defined in the present invention.

First, after forming a first mask layer (2) made of SiOC on both sides of a silicon substrate (1), SiO ₂ is applied to the surface of the first mask layer (2) on the side where the nozzle openings are to be formed. forming a second mask layer (3) consisting of

_In the present invention _, the material for forming the _mask layer is not particularly limited. ), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), hafnium oxide (HfO ₂ ) and tantalum oxide (Ta ₂ O ₃ ), and metal silicate films ( tantalum silicate (TaSiO), etc.) can be used. The thickness of each mask layer is not particularly limited, but is preferably in the range of 50 to 500 nm, for example.

As a method of forming the mask layer, for example, a thermal oxidation method or a CVD method (chemical vapor deposition) is applied to the formation of the second mask layer (3) made of SiO ₂ . CVD method or LPCVD method (low pressure vapor deposition method) can be applied to form the mask layer made of SiN, and the first mask layer (2) made of SiOC can be formed. As for formation, a CVD method can be applied.

The mask layer may be a single layer, a two-layer structure as shown in FIG. 2, or a structure formed on the back side of the silicon substrate.

(Step 3: Formation of first resist layer and formation of annular pattern and polygonal or circular pattern)
The process shown in step S-3 in FIG. 2 is defined in the present invention as "Step 3: A process of forming an annular pattern that will become a nozzle hole in the future and a polygonal or circular pattern on the inner side of the mask layer. , and first, a resist layer 1 (4) is formed on the second mask layer (3).

A positive photoresist or a negative photoresist can be used to form the resist layer. Known materials can be used as the positive photoresist and the negative photoresist. For example, as a negative photoresist, ZPN-1150-90 manufactured by Nippon Zeon Co., Ltd. can be used. As the positive photoresist, OFPR-800LB and OEBR-CAP112PM manufactured by Tokyo Ohka Kogyo Co., Ltd. can be used.

The resist layer is formed by coating with a spin coater or the like so as to have a predetermined thickness. After that, a pre-baking process is performed under conditions such as 110 degrees and 90 seconds.

In order to improve adhesion, HMDS (hexamethyldisilazane) treatment may be performed before resist coating. The HMDS treatment is an organic material called hexamethyldisilazane, and for example, OAP (hexamethyldisilazane) manufactured by Tokyo Ohka Co., Ltd. can be used. As with the resist coating, the coating may be performed using a spin coater, or the effect of improving adhesion can be expected by exposing to hexamethyldisilazane vapor.

Using a predetermined mask, exposure is performed with an aligner or the like. For example, in the case of a contact aligner, the amount of light is about 50 mJ/cm ² . After that, by immersing in a developer (for example, NMD-3 manufactured by Tokyo Ohka for 60 to 90 seconds) to remove the exposed portion of the resist, step S-3 in FIG. 3 and FIG. A resist layer having a resist pattern as shown in (a) is formed.

As a specific mask pattern, as shown in FIG. 4A, an annular pattern (5), which will become nozzle holes in the future, has an outer diameter of 20 to 30 μm and a groove width of 20 to 30 μm. is formed on the resist layer (4) so as to be within the range of 1 to 5 μm.

A polygonal or circular pattern (6) is also formed coaxially inside the annular pattern (5). The size of the polygonal or circular pattern is 5 to 10 μm on one side. One side of the square is parallel to the orientation flat (011) plane of the silicon substrate.

Next, as shown in step S-4 in FIG. 2, dry etching is performed on the first mask layer (2) and the second mask layer (3) having wet etching resistance to form nozzles that are deep-engraved annular patterns. A hole forming portion (5B) and a deeply dug square deep guide hole forming portion (6B) are formed.

As the dry etching 1 (DE1) applied in step S-4, an RIE apparatus that performs deep RIE (Deep Reactive Ion Etching) or an ICP (Inductively Coupled Plasma) that is a dry etching apparatus that employs an inductive coupling method as a discharge method can be used. )—This can be performed using a dry etching device such as an RIE etching device. In addition, etching with excellent verticality can be performed by the Bosch process in which dry etching in the vertical direction is repeated using CHF ₃ or CF ₄ as a process gas.

As an example, using a dry etching apparatus RIE _- 100C manufactured by Samco, the nozzle hole forming part ( 5B) and a deep pit formation portion (6B) can be formed.

Next, in the step shown in step S-5 in FIG. 2, the resist layer 1 formed in steps S-4 and S-5 is removed, and the first mask layer (2) and the second mask layer (3) are removed. This is the step of exposing the pattern.

As a method for removing the resist layer 1, for example, a wet process using acetone or an alkaline solution, or a dry process using oxygen plasma can be used.

(Step 4: Formation of resist layer 2 and deep engraving of polygonal or circular pattern)
The step shown in step S-6 in FIG. 3 is "step 4: forming a resist layer on the annular pattern" defined in the present invention, and the first mask layer (2) and the second mask layer This is a step of covering the circular nozzle hole forming portion (5B) formed in (3) with the resist layer 2 (7). As the resist used for forming the resist layer 2, the materials and methods used for forming the resist layer 1 can be applied.

(b) of FIG. 4 is a top view in step S-6 described above. ) is exposed.

Next, through the step shown in step S-7 in FIG. It is a process of processing. After the resist layer 2 (7) is formed on the annular pattern as described above, the square deep trench forming portion (6B) is penetrated by dry etching (DE2), or partially deep trenched. , forming a deep trench (8).

A square deep trench (8) is formed by deep etching by dry etching, but this deep trench (8) may penetrate through. Etching is performed efficiently, which is desirable.

The dry etching (DE2) can be performed using an ICP-RIE etching apparatus employing an inductively coupled plasma as a discharge method.

In addition, SF ₆ , C ₄ F ₈ , O ₂ , etc., are used as process gases, and the Bosch process, in which film formation and etching are repeated cyclically, enables high-precision, vertical deep-drilling leads (8 ) can be formed.

(Step 5: Removal of resist layer)
In the structure described in step S-7 of FIG. 3, the resist layer 2 is removed by "Step 5: removing the resist layer formed on the annular pattern" defined in the present invention. The resist layer 2 (7) described in step S-7 is removed by, for example, a wet process using acetone or an alkaline solution or a dry process using oxygen plasma, similar to the removal of the resist layer 1 above.

(Step 6: Formation of tapered communication path)
Then, according to the step shown in step S-8 in FIG. A tapered communication path is formed by the step of forming a tapered communication path.

Specifically, after removing the resist layer 2 (7), the single crystal silicon substrate (1) is anisotropically wet-etched to form a tapered communication path (9) extending from a polygonal or circular pattern into an octahedral shape. Form.

The resist layer 2 (7) formed in step S-6 is removed by, for example, a wet process using acetone or an alkaline solution or a dry process using oxygen plasma in the same manner as the removal of the resist layer 1 described above.

Anisotropic etching is then performed on the silicon substrate (1) by wet etching (WE).

A common wet etchant can be used. For example, if a KOH solution is used, the crystal plane selectivity of silicon is good, and if TMAH (tetramethylammonium hydroxide) is used, a mask can be used. Good selectivity between the layer and the silicon substrate is obtained, which is preferable.

For example, by performing wet etching at 70° C. using a 40% by mass aqueous solution of KOH, a shape like an octahedron-shaped taper communicating passage (9) as shown by S-8 in FIG. 3 can be formed. can.

A deep guide hole (8) which is square is formed in the silicon substrate (1) when immersed in an aqueous KOH solution. Etching proceeds so that the (111) plane appears.

That is, when viewed from the surface of the silicon substrate (1), etching starts in a reverse taper, and etching starts in a reverse taper from the bottom surface of the silicon substrate (or etching), and etching proceeds on both sides to form an octahedral shape. Etching stops at this point.

The nozzle hole forming portion (5B) is similarly etched so that the (111) plane appears, but is etched from the silicon substrate side to the forward taper side, and the etching stops when the cross section becomes triangular. As a result, a tapered communication passage (9) having a cross-sectional shape as indicated by S-8 in FIG. 3 is formed.

(Step 7: Formation of straight opening)
The step shown in step S-9 in FIG. 3 is defined in the present invention as “Step 7: Deep etching of the annular pattern by dry etching to penetrate the tapered communication path, and the straight opening that will be the tip of the nozzle hole. forming a part”.

More specifically, the ring-shaped nozzle hole forming portion (5B) is deep-engraved by dry etching (DE2) and penetrated to the tapered communication path to form a straight opening (10) that serves as the tip of the nozzle hole.

After performing wet etching in step S-8, the silicon substrate is washed with flowing water, and then dry etching (DE2) similar to that used in step S-7 is performed to form the nozzle hole forming portion (5B). ) is further advanced, and etching is stopped at the point where it connects with the tapered communication passage (9).

In this method, a nozzle tip portion having the same outer diameter of the nozzle hole forming portion (5B) and the nozzle diameter (R) can be formed with high accuracy.

Next, after forming the tapered communication path (9) and the straight opening (10), as shown in step S-10, the surface of the single crystal silicon substrate opposite to the surface on which the straight opening is provided is cut. A nozzle plate (NP) having a predetermined thickness is manufactured by grinding and polishing up to the central portion of the tapered communication passage .

(Step 8: Nozzle plate chips)
Finally, according to the step 8 specified in the present invention, the outer diameter is adjusted to a predetermined size and chipped, and cut by dicing or the like according to the outer diameter of the nozzle plate to obtain a nozzle plate of a predetermined size. (NP) is produced.

[Embodiment 2: Manufacturing Example 2 of Nozzle Plate]
In the method of manufacturing the nozzle plate of the present invention, the surfaces of the tapered communicating passage and the straight opening may be covered with a protective film having ink resistance, or an ink-repellent layer may be formed on the outermost surface. This is preferable in that a nozzle plate having durability and stable ejection can be formed.

In FIG. 5, a tapered communicating path (9) and a straight opening (10) are provided in a silicon substrate (1), and a first mask layer (2) is provided on the surface. The structure of a nozzle plate (NP) having a protective film (11) formed on the surface of a straight opening (10) and an ink-repellent layer (12) on the outermost surface is shown.

The protective film (11) is made of a material that does not dissolve upon contact with ink, such as a metal oxide film (tantalum pentoxide, hafnium oxide, niobium oxide, titanium oxide, zirconium oxide, etc.), or a metal oxide film containing silicon. The material used for forming the contained metal silicate film (tantalum silicate, hafnium silicate, niobium silicate, titanium silicate, zirconium silicate, etc.) and the mask layer can be selected and used. Also, an organic film such as polyimide, polyamide, or parylene may be used as the protective film (11). The thickness of the protective film (11) is not particularly limited, but can be, for example, 1 to several tens of μm.

The material for forming the ink-repellent layer (12) contains a fluorine-based compound, and the fluorine-based compound has (1) at least a perfluoroalkyl group containing an alkoxysilyl group, a phosphonic acid group, or a hydroxyl group. compound, or a compound having a perfluoropolyether group containing an alkoxysilyl group, a phosphonic acid group or a hydroxy group, or (2) a mixture containing a compound having a perfluoroalkyl group, or a compound having a perfluoropolyether group It is preferably a mixture containing

Fluorine-based compounds are also available as commercial products. , Cytop), Seco Co., Ltd. (eg, Top CleanSafe (registered trademark)), Fluorotechnology Co., Ltd. (eg, Fluorosurf), Gelest Inc. It is marketed by Solvay Solexis Co., Ltd. (eg, Fluorolink S10), etc., and is easily available. Fluorine Chem. , 79(1). 87 (1996), Materials Technology, 16(5), 209 (1998), Collect. Czech. Chem. Commun. 44, pp. 750-755, J. Am. Amer. Chem. Soc. 1990, 112, 2341-2348, Inorg. Chem. , vol. 10, pp. 889-892, 1971, US Pat. 11-29585, JP-A-2000-64348, JP-A-2000-144097, etc., or a synthesis method based thereon.

[Embodiment 3: Manufacturing Example of Nozzle Plate Having Straight Communication Part]
As a manufacturing method of the nozzle plate of the present invention, in addition to the manufacturing method of Embodiment 1 described with reference to FIGS. A method for manufacturing a nozzle plate having portions (Embodiment 3) is also preferred.

6 and 7 are sectional views (Embodiment 3) showing another example of the manufacturing method of the typical nozzle plate of the present invention.

In the third embodiment, the steps up to forming the tapered communication path (9) and the straight opening (10) are the same as steps S-1 to S-9 described in detail in the first embodiment.

(Step S-11: Removal of first mask layer)
Step S-4 and the like are performed on the silicon substrate (1) having the first mask layer (2) on both sides of the tapered communication path (9) and the straight opening (10) formed up to step S-9. The first mask layer (2) formed on the surface and made of SiOC is removed by dry etching similar to that used in .

Dry etching uses a fluorine-based gas such as CF ₄ or CHF ₃ . As etching conditions, for example, the gas flow rate of CF ₄ or CHF ₃ is 80 sccm, the pressure is 3 Pa, and the RF power is 90 W. Etching can be performed for a predetermined period of time.

(Step S-12: Form an oxide film on the surface of the nozzle plate)
In step S-12, an oxide film (13) made of SiO ₂ is formed on the entire surface of the silicon substrate (1) by thermal oxidation.

As the thermal oxidation treatment, there are a dry oxidation method using oxygen gas and a wet oxidation method using water vapor, and either method can be adopted as thermal oxidation. The heating temperature is about 900 to 1200° C. for dry oxidation and about 800 to 1100° C. for wet oxidation. For example, when wet oxidation is used, a thermal oxide film (13) having a thickness of 1 μm can be formed on the entire surface of the silicon substrate by heating at 1000° C. for about 4 hours.

(Step S-13: Form resist layer)
Next, after changing the configuration described in step S-12 to an upside-down arrangement, the resist layer 3 (14) is formed on the surface to cover the width (long side) of the tapered communication path (9). formed by

By adopting this configuration, a pattern is formed that will become the communication path (9B) formed in step S-16. The shape of the communication path (9B) can be circular, square, rectangular, or any other configuration. The length of one side or diameter is in the range of 50 to 200 μm.

(Step S-14: Removal of surface oxide film)
Next, the surface oxide film (13) formed in step S-12 is removed by dry etching similar to the above.

(Step S-15: Deep etching of silicon substrate)
Next, from the surface side, using the same dry etching (DE2) as used in steps S-7 and S-9 of Embodiment 1, the silicon is deeply etched until both ends of the tapered communication path (9) are reached. did

(Step S-16: Removal of resist layer and thermal oxide film)
Finally, the resist layer 3 (14) and the thermal oxide film (12) were removed by the same method as described above, and a nozzle plate (NP) was produced by the manufacturing method according to the third embodiment.

[Shape of nozzle plate]
In the nozzle plate according to the present invention, it is preferable that the angle (θ2) formed by the upper surface of the tip of the nozzle hole and the side surface of the straight opening is within the range of 70 to 90 degrees.

FIG. 8 is a cross-sectional view for explaining the angle (θ2) formed by the upper surface of the tip of the nozzle hole and the side surface of the straight opening and the angle (θ1) formed by the taper communicating portion in the nozzle plate of the present invention. is.

As shown in FIG. 8, the angle (θ1) of the taper connecting portion (9) is always 55 degrees due to the influence of the crystal orientation of silicon. On the other hand, the angle (θ2) formed by the upper surface (Sa) of the tip of the nozzle hole and the side surface (Sb) of the straight opening is set within the range of 70 to 90 degrees from the viewpoint of obtaining stable ink ejection. It is preferable to set

[Composition of other nozzle plates]
6 and 7, in addition to the straight opening (10) and the tapered communication path (9), a method of forming the straight communication part (9B) by a series of manufacturing processes was described. As described, a manufacturing method for forming the straight communication portion (9B) in an independent process can also be mentioned.

[Embodiment 4: Formation of straight communicating portion by communicating path plate]
FIG. 9 is a cross-sectional view (Embodiment 4) showing an example of a configuration in which a communicating path plate is connected to a nozzle plate.

In the fourth embodiment, the steps up to forming the tapered communication path (9) and the straight opening (10) are steps S-1 to S- described in detail with reference to FIGS. 2 and 3 in the first embodiment. It is the same process as up to 9.

As shown in FIG. 9, a separately prepared communicating passage is attached to the bottom surface of the tapered communicating passage (9) of the nozzle plate (NP) prepared in step S-10 shown in FIG. 3 via an adhesive layer (15). This is a method of joining plates (16) to form a straight communication path (9B).

A silicon member is desirable as a material for forming the communicating path plate (16), but metals such as SUS and Ni, and resins such as polyimide may also be used.

Moreover, as a material constituting the adhesive layer (15), an adhesive such as an epoxy resin may be used for bonding. If the communication path plate is made of silicon, activation bonding of Si—Si or Si—SiO ₂ —Si can be used, and bonding without using an adhesive is also possible. It is preferable in terms of excellent strength in. Also, a bonding method such as Au--Si bonding via a metal is possible.

[Embodiment 5: Formation of straight communication part by Ni electroforming]
FIG. 10 is a cross-sectional view (Embodiment 5) showing an example of the configuration of a nozzle plate in which a straight communication portion is formed by Ni electroforming in the nozzle plate.

In Embodiment 5, the steps up to forming the tapered communication path (9) and the straight opening (10) are steps S-1 to S- described in detail with reference to FIGS. 2 and 3 in Embodiment 1. It is the same process as up to 9.

As shown in FIG. 10, Ni electroforming or the like is applied to the bottom surface of the tapered communication passage (9) of the nozzle plate (NP) produced in step S-10 shown in FIG. 3 via the seed layer (17). , a method of forming a straight communication path (9B).

First, a seed layer (17) made of Ni or the like is formed on the bottom surface of the tapered communication passage (9) of the nozzle plate (NP) produced in step S-10 shown in FIG. Next, a straight communication path (9B) is formed by Ni electroforming (thick electroforming).

《Inkjet head》
A method for manufacturing an ink jet head according to the present invention is characterized by including each of the manufacturing steps in the above-described method for manufacturing a nozzle plate according to the present invention.

[Structure of inkjet head]
Details of an inkjet head that can be equipped with a nozzle plate manufactured by the method for manufacturing a nozzle plate of the present invention will be described.

FIG. 11 is a cross-sectional view showing an example of the configuration of an inkjet head equipped with a nozzle plate according to the present invention.

FIG. 11 is a cross-sectional view of the inkjet head (101) viewed from the side (-X direction). FIG. 11 shows a cross section of the inkjet head (101) in a plane including four nozzles (N) included in four nozzle rows.

The inkjet head (101) comprises a head chip (102), a common ink chamber (170), a support substrate (180), a wiring member (103), a drive section (104) and the like.

The head chip (102) is a structure for ejecting ink from the nozzle (N), and is formed by laminating a plurality of plate-like substrates (four in FIG. 11). The lowest substrate in the head chip (102) is a nozzle plate (110, nozzle forming member). The nozzle plate (110) is provided with a plurality of nozzles (N) having a structure according to the present invention, and the exposed surface (ink ejection surface (101a)) of the nozzle plate (110) is exposed from the openings of the nozzles (N). Ink can be ejected substantially perpendicularly to the . A pressure chamber substrate (120, chamber plate), a spacer substrate (140) and a wiring substrate are arranged in order upward (in the Z direction in FIG. 11) on the opposite side of the nozzle plate (110) to the ink ejection surface (101a). (150) is glued and laminated. Hereinafter, the nozzle plate (110), pressure chamber substrate (120), spacer substrate (140) and wiring substrate (150) are also referred to as laminated substrates (110, 120, 140, 150).

These laminated substrates (110, 120, 140, 150) are provided with ink flow paths communicating with the nozzles (N). is open. A common ink chamber (170) is provided on the exposed surface of the wiring board (150) so as to cover all openings. Ink stored in an ink chamber forming member (not shown) of the common ink chamber (170) is supplied to each nozzle (N) from an opening of the wiring board (150).

In addition, in the nozzle plate (110) shown in FIG. 11, detailed description of the tapered communication passage and the straight opening in the nozzle (N), which is the feature of the present invention, is omitted.

A pressure chamber (121, ink reservoir) is provided in the middle of the ink flow path. The pressure chamber (121) is provided so as to penetrate the pressure chamber substrate (120) in the vertical direction (Z direction). It is composed of a diaphragm (130) provided between. The ink in the pressure chamber (121) is displaced (deformed) by the piezoelectric element (160) in the storage section (141) provided adjacent to the pressure chamber (121) via the diaphragm (130). A pressure change is applied by deformation of the diaphragm (130) and the pressure chamber (121). By applying an appropriate pressure change to the ink in the pressure chamber (121), the ink in the ink channel is ejected as droplets from the nozzle (N) communicating with the pressure chamber (121).

A support substrate (180) is bonded to the upper surface of the head chip 2 and holds an ink chamber forming member (not shown) of the common ink chamber (170). The support substrate (180) is provided with an opening having substantially the same size and shape as the opening in the lower surface of the ink chamber forming member (not shown). and the opening of the support substrate (180) to the upper surface of the head chip (102).

The wiring member (103) is, for example, FPC (Flexible Printed Circuits) or the like, and is connected to the wiring of the wiring board (150). A piezoelectric element (160) is displaced by a drive signal that is transmitted to the wiring (151) and the connecting part (152, conductive member) in the storage part (141) through this wiring. The wiring member (103) penetrates through the support substrate (180) and is drawn out to be connected to the drive section (104).

A drive unit (104) receives a control signal from the control unit of the inkjet recording apparatus, power supply from a power supply unit, and the like, and operates a piezoelectric element ( 160) to the wiring member (103). The drive unit (104) is composed of an IC (Integrated Circuit) or the like.

The ink jet head having the structure described above can be manufactured using the nozzle plate manufactured by the method for manufacturing a nozzle plate according to the present invention.

A nozzle plate manufactured by a nozzle plate manufacturing method capable of forming the dimensional accuracy of the nozzle diameter according to the present invention and the tapered communicating passages and straight openings of the nozzles with high accuracy without variations in the central axis is used for the inkjet head. , the tapered communication passage that constitutes the nozzle plate having the characteristics described above is stable against pressure fluctuations in the pressure chamber and fluctuations in the ink meniscus position during ink ejection from the inkjet head. Highly accurate ink ejection characteristics can be obtained.

In addition, since the straight opening (nozzle hole) is formed after forming the tapered communicating passage by wet etching, which is a feature of the manufacturing method of the nozzle plate of the present invention, manufacturing defects such as chipping at the tip of the nozzle hole occur. As a result, highly accurate ink ejection is possible. Further, the nozzle hole forming portion (5) and the deep conductive portion forming portion (6) for forming the taper communication path use a common pattern forming material (resist layer 1), and the pattern is formed by the same exposure operation. Since it is formed, there is no occurrence of rubbing between the tapered communication path and the center line of the straight opening formed by each, and no bending of the ink occurs at the time of ink ejection, and stable ink ejection characteristics can be obtained.

REFERENCE SIGNS LIST 1 silicon substrate 2 first mask layer 3 second mask layer 4 resist layer 1
5 annular pattern 5B nozzle hole forming part 6 polygonal or circular pattern 6B lead hole forming part for deep excavation 7 resist layer 2
8 Deep guide hole 9 Tapered communication path 9B Straight communication part 10 Straight opening (nozzle hole)
REFERENCE SIGNS LIST 11 protective film 12 ink-repellent layer 13 oxide film 14 resist layer 3
15 adhesive layer 16 communication path plate 17 seed layer 18 Ni electroforming 101 inkjet head 101a ink discharge surface 102 head chip 103 wiring member 104 driving unit 110 nozzle plate 120 pressure chamber substrate 121 pressure chamber 130 diaphragm 140 spacer substrate 150 wiring substrate 160 Piezoelectric element 170 Common ink chamber 180 Support substrate C1, C2, C3 Central axis DE1, DE2 Dry etching N Nozzle NP Nozzle plate R Nozzle diameter Sa Top surface of nozzle tip Sb Side of straight opening WE Wet etching θ1 Tip of nozzle hole Angle θ2 Angle of taper passage

Claims (6)

A method for manufacturing a nozzle plate having at least a tapered communication passage and a straight opening forming a nozzle portion,
A method for manufacturing a nozzle plate, characterized by manufacturing a nozzle plate through at least steps 1 to 8 below.
Step 1: a step of preparing a single crystal silicon substrate having a (100) surface;
Step 2: a step of uniformly forming a mask layer on the surface of the single crystal silicon substrate;
Step 3: A step of forming an annular pattern, which will become a nozzle hole in the future, and a polygonal or circular pattern inside it, on the mask layer;
Step 4: A step of forming a resist layer on the annular pattern and penetrating or partly deep-etching the polygonal or circular pattern by dry etching;
Step 5: removing the resist layer formed on the annular pattern;
Step 6: A step of anisotropically wet-etching the single crystal silicon substrate to form the tapered communication path extending from the polygonal or circular pattern into an octahedral shape;
Step 7: A step of forming the straight opening that will be the tip of the nozzle hole by penetrating the annular pattern to the tapered communication path by deep etching by dry etching;
Step 8: A step of trimming the outside diameter to a predetermined size and chipping. 2. After said step 7, a step of grinding and polishing the surface opposite to the surface of said single crystal silicon substrate on which said straight opening is provided is provided up to the center portion of said tapered communication passage . A method for manufacturing the nozzle plate according to 1. 3. The nozzle plate according to claim 1, wherein the angle (θ2) formed by the upper surface of the tip of the nozzle hole and the side surface of the straight opening is within the range of 70 to 90 degrees. manufacturing method. 4. The method of manufacturing a nozzle plate according to any one of claims 1 to 3, wherein surfaces of the tapered communication passage and the straight opening are covered with a protective film having ink resistance. 5. The method of manufacturing a nozzle plate according to any one of claims 1 to 4, wherein an ink-repellent layer is formed on the outermost surface. A method for manufacturing an inkjet head, comprising Steps 1 to 8 in the method for manufacturing a nozzle plate according to any one of Claims 1 to 5.

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