Method of manufacturing a nozzle plate, nozzle plate and fluid ejection head

Abstract

Through the following steps (1) to (5), a nozzle plate is manufactured having at least a nozzle cone (12) and a straight connecting path (13) in the nozzle hole. Step 1 (S-1): A step of preparing a single crystal silicon substrate (1) with a crystal orientation of (100) on its surface; Step 2 (S-2): A step of forming a mask layer (2) on the surface of the single crystal silicon substrate; Step 3 (S-3): A step of forming an opening pattern 3 on the mask layer; Step 4 (S-4): A step of forming a through hole 4 by dry etching through the surface of the single crystal silicon substrate located under the opening pattern; Step 5 (S-5): A step of enlarging the through hole by anisotropic wet etching of the single crystal silicon substrate, thereby forming a nozzle cone and a straight connecting path continuous with the nozzle cone.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a nozzle plate, the nozzle plate itself, and a fluid nozzle. Background Technology

[0002] Previously, a method for manufacturing a nozzle plate having a nozzle cone and a straight connecting path in the nozzle orifice has been proposed. Such a method for manufacturing a nozzle plate is disclosed, for example, in Patent Document 1 and Patent Document 2.

[0003] Patent document 1 discloses a method for manufacturing a funnel-shaped nozzle plate with a nozzle cone and a nozzle cylinder formed on a silicon wafer, i.e., an SOI (Silicon On Insulator) substrate, which has a silicon single crystal layer formed on an oxide film.

[0004] In Patent Document 1, a rear hole is etched by patterning a photoresist from the opposite side, relative to a front hole formed by wet etching. That is, a method in which a hole drilled from one side of a substrate and a hole drilled from another side of a substrate merge and pass through each other within the substrate.

[0005] In Patent Document 2, since wet etching is performed from top to bottom instead of through a single-sided hole, the same method applies.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent No. 5519263

[0009] Patent Document 2: Japanese Patent Publication No. 2014-512989 Summary of the Invention

[0010] In the aforementioned prior art, holes drilled from one side of the substrate and holes drilled from another side merge and connect within the substrate to form nozzle holes. However, positional offset between holes drilled from one side and holes drilled from another side is unavoidable.

[0011] Therefore, if the existing manufacturing method described above is used, the fluid flow loses its symmetry due to the positional offset between the nozzle cone and the straight connecting path, which may lead to a deterioration of the injection angle. In addition, due to this positional offset, sediment is generated in the nozzle, and bubbles are trapped there, which also deteriorates the defoaming performance.

[0012] The present invention was made in view of the above-mentioned problems, and the solution thereto is a nozzle plate formed by the continuous connection of the nozzle cone and the straight connecting path in a positional manner, and a fluid nozzle having the nozzle plate.

[0013] One aspect of the present invention that solves the above-mentioned problems is a method for manufacturing a nozzle plate, which is a method for manufacturing a nozzle plate for a fluid nozzle head, wherein a nozzle plate having at least a nozzle cone and a straight connecting path in a nozzle orifice is manufactured by means of the following steps 1 to 5.

[0014] Step 1: The process of preparing a single-crystal silicon substrate with a crystal orientation of

[100] plane.

[0015] Step 2: The same process of forming a mask layer on the surface of the monocrystalline silicon substrate described above.

[0016] Step 3: The step of forming an opening pattern in the above-mentioned mask layer.

[0017] Step 4: A process of forming through holes by dry etching the surface of the monocrystalline silicon substrate located under the above-mentioned opening pattern.

[0018] Step 5: A step of enlarging the through hole by anisotropic wet etching of the above-mentioned single crystal silicon substrate, thereby forming a nozzle cone and a straight connecting path continuous with the nozzle cone.

[0019] Another aspect of the present invention is a nozzle plate for a fluid nozzle having a straight connecting path consisting of four

[100] surfaces that is continuous in the direction of increasing diameter relative to the nozzle cone consisting of four

[111] surfaces of monocrystalline silicon.

[0020] According to the above-described method for manufacturing a nozzle plate for a fluid nozzle, for a nozzle, a nozzle cone and a straight connecting path are formed by enlarging a through hole formed through an opening pattern, thereby enabling the nozzle plate to be formed continuously with the nozzle cone and the straight connecting path in a positional manner without offset.

[0021] According to one aspect of the present invention, the nozzle plate maintains symmetrical fluid flow and a stable ejection angle because the nozzle cone and the straight connecting path are continuous without positional deviation. Furthermore, it is less prone to sedimentation within the nozzle and exhibits good defoaming properties. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view showing the main steps of the method for manufacturing a nozzle plate according to the first embodiment of the present invention.

[0023] Figure 2 This is a rear view of the nozzle plate according to the first embodiment of the present invention, showing the nozzle orifice portion.

[0024] Figure 3 This is a cross-sectional view of the nozzle plate according to the first embodiment of the present invention, showing the case where a protective film has been applied.

[0025] Figure 4This is a cross-sectional view showing the main steps of the nozzle plate manufacturing method according to the second embodiment of the present invention.

[0026] Figure 5 This is a cross-sectional view of the nozzle plate according to the second embodiment of the present invention, showing the case where a protective film is applied.

[0027] Figure 6 This is a rear view of the nozzle plate according to the first and second embodiments of the present invention, showing the nozzle hole and its surrounding portion.

[0028] Figure 7 express Figure 6 Section A2-A2 (in the case of the second embodiment).

[0029] Figure 8 This is a cross-sectional view showing an example of the structure of a fluid nozzle (inkjet head).

[0030] Figure 9 This is a cross-sectional view showing the main steps of the nozzle plate manufacturing method according to Embodiment 1 of the present invention.

[0031] Figure 10 This is a cross-sectional view showing the main steps of the manufacturing method of the nozzle plate of Comparative Example 1. Detailed Implementation

[0032] [First Implementation]

[0033] First, the method for manufacturing the nozzle plate according to the first embodiment of the present invention and the nozzle plate manufactured therefrom will be described.

[0034] The method for manufacturing the nozzle plate of the present invention is a method for manufacturing the nozzle plate of a fluid nozzle head, which is a method for manufacturing a nozzle plate having at least a nozzle cone and a straight connecting path in the nozzle orifice through the following steps 1 to 5. Figure 1 A reference numeral is shown for steps 1 (S-1) to 5 (S-5).

[0035] First, as process 1 ( Figure 1 S-1), a single-crystal silicon substrate 1 with a crystal orientation of

[100] is prepared. The single-crystal silicon substrate 1 with a surface orientation of

[100] is a plate-shaped component made of silicon with a thickness of about 100 to 725 μm. By using the single-crystal silicon substrate 1 as the substrate of the nozzle substrate, the nozzle plate can be processed with high precision, and a nozzle plate with less positional error and shape deviation can be formed.

[0036] Next, as process 2 ( Figure 1 S-2), a mask layer 2 is similarly formed on the surface of the single crystal silicon substrate 1.

[0037] There are no particular restrictions on the material used to form mask layer 2; for example, SiO2 (silicon oxide), SiN (silicon nitride), Al (aluminum), Cr (chromium), etc., can be used.

[0038] As for the formation method of mask layer 2, for example, for the formation of mask layer 2 composed of SiO2, thermal oxidation and CVD (chemical vapor deposition) methods can be used; for the formation of mask layer 2 composed of SiN, CVD and LPCVD (low-pressure vapor deposition) methods can be applied. Preferably, SiO2 is based on thermal oxidation. SiO2 has good adhesion to Si, which helps prevent side etching during anisotropic wet etching.

[0039] Mask layer 2 can be Figure 1 The single layer shown can also be composed of two layers. In addition, the mask layer 2 can also be formed on the back side of the silicon substrate 1 in this process.

[0040] Next, as process 3 ( Figure 1 S-3), a circular or polygonal opening pattern 3 is formed in the mask layer 2.

[0041] In detail, a resist pattern is formed on the mask layer 2 using known photolithography techniques. The resist pattern is then used as a mask to perform dry etching (DE1) on the mask layer 2, thereby forming the opening pattern 3.

[0042] In the formation of the resist layer, either a positive or negative photoresist can be used. Known materials can be used as both positive and negative photoresists. For example, ZPN-1150-90 manufactured by ZEON Corporation of Japan can be used as a negative photoresist. Alternatively, OFPR-800LB and OEBR-CAP112PM manufactured by Tokyo Ohka Kogyo Co., Ltd. can be used as positive photoresists.

[0043] The resist layer is formed by applying it to a specified thickness using a spin coater or similar method. Then, it is pre-baked at 110°C for 90 seconds or similar conditions.

[0044] To improve adhesion, HMDS (hexamethyldisilazane) treatment can be performed before resist coating. HMDS treatment can be performed using organic materials called hexamethyldisilazane, such as OAP (hexamethyldisilazane) manufactured by Tokyo Ohka Kogyo Co., Ltd. Resist coating can also be performed using a spin coater, and improved adhesion can be expected even when exposed to hexamethyldisilazane vapor.

[0045] Using a prescribed mask, the resist layer is exposed using a corrector or similar device. For example, when using a contact corrector, the concentration is approximately 50 mJ / cm. 2 The light intensity is then applied. The photosensitive portion of the resist layer is then removed by immersion in a developing solution (e.g., Tokyo Ohka Kogyo NMD-3 for 60-90 seconds), thereby forming a resist pattern on the mask layer 2.

[0046] The mask layer 2 is dry-etched (DE1) using the resist pattern as a mask to form the opening pattern 3. The resist pattern is then removed.

[0047] At this time, as dry etching (DE1), it can be performed using RIE (Reactive Ion Etching) devices, ICP (Inductively Coupled Plasma)-RIE etching devices, and other dry etching devices that use inductive coupling for discharge. Additionally, CHF3, CF4, etc., can be used as process gases.

[0048] As an example, using the RIE-100C dry etching apparatus manufactured by Samco, etching was performed for a specified time with the CHF3 gas flow rate set to 80 sccm, the pressure set to 3 Pa, and the RF power set to 90 W, thereby forming the opening pattern 3.

[0049] As a method for removing resist patterns, they can be removed, for example, by using a wet process with acetone or alkaline solution, or by a dry process using oxygen plasma.

[0050] Next, as process 4 ( Figure 1 S-4) The monocrystalline silicon substrate 1 located under the opening pattern 3 is subjected to dry etching (DE2) from the surface to form a through hole 4.

[0051] At this point, dry etching (DE2) can be performed using an ICP-RIE etching apparatus that employs inductively coupled plasma in the form of discharge.

[0052] In addition, process gases such as SF6, C4F8, and O2 are used. By using the Bosch process of cyclically repeating film formation and etching, vertical through holes 4 can be formed with high precision.

[0053] Next, as process 5 ( Figure 1 S-5) By using anisotropic wet etching (WE) on the single-crystal silicon substrate 1 to enlarge the through hole 4, a nozzle cone 12 and a straight connecting path 13 continuous with the nozzle cone 12 are formed.

[0054] The anisotropic wet etching (WE) process in step 5 uses alkaline aqueous solutions such as KOH, TMAH (tetramethylammonium hydroxide), and EDP (ethylenediamine catechol). The nozzle cone 12 is the

[111] face of the Si single crystal. Since the etching rate of the

[111] face is extremely slow, the cone is formed at an angle θ of 54.7 degrees as shown in the figure.

[0055] For example, by using a 40% by mass aqueous solution of KOH and performing wet etching at 70°C, it is possible to form... Figure 1 S-5 and Figure 2 The nozzle cone 12 and the straight connecting path 13 are shown in the back view.

[0056] The nozzle cone 12 is designed so that the nozzle tip outlet 11 is the small-diameter end. The straight connecting path 13 is continuous with the large-diameter end of the nozzle cone 12.

[0057] The inner surface F1 of the nozzle cone 12 is composed of four surfaces. These four surfaces F1 are the

[111] surfaces.

[0058] The angle θ between the surface of the silicon substrate 1 with the nozzle outlet 11 and the surface F1 is 54.7 degrees.

[0059] The inner surface F2 of the straight connecting path 13 is also composed of 4 faces. These 4 faces F2 are called the

[100] face.

[0060] Therefore, the nozzle plate 10A manufactured as described above has a straight connecting path 13 composed of four

[100] surfaces that is continuous in the direction of increasing diameter relative to the nozzle cone 12 composed of four

[111] surfaces of the monocrystalline silicon.

[0061] According to the above-described method for manufacturing a nozzle plate according to the first embodiment of the present invention, for a nozzle, by enlarging the through hole 4 formed through an opening pattern 3, a nozzle cone 12 and a straight connecting path 13 are formed, so that a nozzle plate 10A with a nozzle hole can be formed by continuously forming the nozzle cone 12 and the straight connecting path 13 without positional offset.

[0062] According to the first embodiment of the nozzle plate 10A of the present invention, the nozzle cone 12 and the straight connecting path 13 are connected without positional offset, so the fluid flow maintains symmetry and the ejection angle is stable. In addition, sedimentation is not easily generated in the nozzle, and the defoaming property is also good.

[0063] In addition, since it is used for fluid discharge for a long time, it can be used in nozzle plate 10A, such as Figure 3 A protective film 21 is formed as shown. In this case, after step 5 (S-5), a step is performed to form a protective film 21 covering the surface including the inside of the nozzle cone 12 and the straight connecting path 13.

[0064] As the protective film 21, a material that will not dissolve upon contact with the discharged fluid (ink, etc.) can be selected. For example, a metal oxide film (tantalum pentoxide, hafnium oxide, niobium oxide, titanium oxide, zirconium oxide, etc.), a metal silicate film containing silicon in the metal oxide film (tantalum silicate, hafnium silicate, niobium silicate, titanium silicate, zirconium silicate, etc.), or any material used to form the aforementioned mask layer can be selected as the protective film 21. Alternatively, organic films such as polyimide, polyamide, and parylene can be used as the protective film 21. The thickness of the protective film 21 is not particularly limited, and can be, for example, from 0.05 to 20 μm.

[0065] [Second Implementation]

[0066] Next, the method for manufacturing the nozzle plate according to the second embodiment of the present invention and the nozzle plate manufactured therefrom will be described.

[0067] The method for manufacturing the nozzle plate according to the second embodiment of the present invention is to perform the following steps 6 and 7 between steps 3 and 4 of the first embodiment to provide a nozzle straight section 14 with the nozzle front end outlet 11 as one end.

[0068] Figure 4 The diagram shows steps 6 (S-6), 7 (S-7), and steps 4 (S-4) and 5 (S-5) following step 7.

[0069] Steps 1-3 are performed in the same manner as in the first embodiment described above.

[0070] Next, as process 6 ( Figure 4 S-6) The single-crystal silicon substrate 1 located under the opening pattern 3 is subjected to deep drilling from the surface by dry etching (DE3) to form the hole 5.

[0071] The dry etching (DE3) in this process can be performed using the same method as the dry etching (DE2) in process 4. In this process, the etching ends after excavating the predetermined length of the nozzle cylindrical section 14, without penetrating through.

[0072] Next, as process 7 ( Figure 4 S-7), a mask layer 6 is formed on the sidewall of the hole 5.

[0073] The mask layer 6 in this process is formed using the same material and method as the mask layer 2 in process 2. The mask layer at the bottom of the hole 5 is removed using a resist pattern and dry etching (DE4) in the same manner as in process 3.

[0074] It should be noted that the mask layers 2 and 6 in processes 2 and 7 can be formed on the surface and back of the silicon substrate 1 using methods such as thermal oxidation. However, when they are formed on both sides, the mask layer at the bottom of the through-hole 4 needs to be removed at least before process 5. If the mask layer remains at the bottom of the through-hole 4, the etchant will remain inside the through-hole 4 during the anisotropic wet etching in the subsequent process 5. The H2 gas generated by the reaction between the alkaline wet etchant and Si will also remain, thus delaying the etching process and causing shape deviations.

[0075] Then, step 4 is performed in the same manner as in the first embodiment described above. Figure 4 S-4), then proceed to step 5 ( Figure 4 S-5). In process 4 ( Figure 4 In step S-4), the bottom of hole 5 is excavated to form through hole 4. Step 5 ( Figure 4 In S-5), the portion of Si exposed under the mask layer 6 in the through hole 4 expands to form a nozzle cone 12 and a straight connecting path 13 that communicate with the nozzle cylindrical portion 14.

[0076] According to the manufacturing method of the second embodiment described above, it is possible to manufacture a nozzle plate 10B having a nozzle straight section 14 with a desired length at the nozzle tip.

[0077] The nozzle straight section 14 has one end serving as the nozzle front outlet 11 and the other end serving as the small diameter end of the nozzle cone section 12.

[0078] In the nozzle plate 10B, similarly to the nozzle plate 10A of the first embodiment described above, the cone angle θ is 54.7 degrees, the four inner surfaces F1 of the nozzle cone 12 are

[111] surfaces, and the four inner surfaces F2 of the straight connecting path 13 are

[100] surfaces.

[0079] According to the above-described method for manufacturing a nozzle plate according to the second embodiment of the present invention, similarly to the first embodiment described above, for a single nozzle, the through hole 4 formed through an opening pattern 3 is enlarged to form a nozzle cone 12 and a straight connecting path 13, so that a nozzle plate 10B with a nozzle hole can be formed by continuously forming the nozzle cone 12 and the straight connecting path 13 without positional offset.

[0080] According to the second embodiment of the nozzle plate manufacturing method of the present invention, the sidewall of the hole 5 is protected by the mask layer 6, in step 5 ( Figure 4 In the anisotropic wet etching (WE) of S-5, there is no erosion, and the nozzle straight section 14 can be formed. The nozzle straight section 14 and the nozzle cone section 12 can also be continuous without positional offset.

[0081] According to the second embodiment of the nozzle plate 10B of the present invention, similarly to the first embodiment described above, the nozzle cone 12 and the straight connecting path 13 are continuous without positional offset, and consequently the nozzle cylinder 14 and the nozzle cone 12 are also continuous without positional offset. Therefore, the fluid flow maintains symmetry and the injection angle is stable. In addition, sedimentation is less likely to occur in the nozzle, and defoaming properties are also good.

[0082] According to the second embodiment of the nozzle plate 10A, the nozzle cone portion 12 and the nozzle straight portion 14 are continuous without positional offset, so the ejection angle is further stabilized.

[0083] Additionally, similar to the first embodiment described above, the nozzle plate 10B can also be modified as follows: Figure 5 A protective film 22 is formed as shown. In this case, after step 5 (S-5), a step is performed to form a protective film 22 covering the surfaces including the inside of the nozzle cylinder 14, the inside of the nozzle cone 12, and the inside of the straight connecting path 13.

[0084] In the first and second embodiments described above, the nozzle tip outlet 11 in step 3 can have any shape as long as it can discharge in a circular or polygonal pattern. Any shape has no effect on the connection between the nozzle cone 12 and the straight connecting path 13.

[0085] After step 5 of the first and second embodiments described above, the mask layer 2 may not need to be removed, or other forms may be used. The connection between the nozzle cone 12 and the straight connecting path 13 is not affected.

[0086] Furthermore, after step 5 of the first and second embodiments described above, a phenomenon appeared on the back side of the monocrystalline silicon substrate 1. Figure 6 , 7 The crystallization surface F3 is shown, but the connection between the nozzle cone 12 and the straight connecting path 13 is not affected, so direct use is not a problem. However, even if the nozzle plate is thinned and part of the crystallization surface F3 is eliminated through back-side grinding or other machining processes, there is no problem. It should be noted that... Figure 7 Equivalent to Figure 6 In the diagram, A2-A2 represents the second embodiment. Figure 1 , Figure 4 The cross-sectional view is equivalent to Figure 2 , Figure 6 The A1-A1 section shown in the figure.

[0087] [Fluid nozzle]

[0088] The nozzle plates (10A, 10B) described above are used as the nozzle plates (110) of the fluid printhead (101) disclosed below. Hereinafter, an example of the structure of an inkjet head is disclosed as a structural example of a fluid printhead.

[0089] (Example of inkjet head structure)

[0090] Figure 8 This is a cross-sectional view of the inkjet head (101) viewed from the side (X direction side). Figure 8 The image shows a cross-section of an inkjet head (101) in a face containing four nozzles (N) in four nozzle rows.

[0091] The inkjet head (101) consists of a printhead chip (102), a common ink chamber (170), a support substrate (180), wiring components (103), and a drive unit (104).

[0092] The printhead chip (102) is a component used to eject ink from the nozzle (N), and there are multiple of them. Figure 8 Four plate-shaped substrates are stacked together. The bottom substrate of the printhead chip (102) is a nozzle plate (110, nozzle forming component). A plurality of nozzles (N) having the structure of the present invention are provided on the nozzle plate (110), and ink can be discharged substantially perpendicularly from the opening of the nozzle (N) (corresponding to the aforementioned "nozzle front end outlet 11") relative to the exposed surface (ink discharge surface (101a)) of the nozzle plate (110). On the side of the nozzle plate (110) opposite to the ink discharge surface (101a), facing upwards (… Figure 8 A pressure chamber substrate (120, chamber plate), a spacer substrate (140), and a wiring substrate (150) are sequentially bonded and stacked in the Z direction. Hereinafter, each substrate of these nozzle plate (110), pressure chamber substrate (120), spacer substrate (140), and wiring substrate (150) will also be referred to as a stacked substrate (110, 120, 140, 150), etc.

[0093] In these laminated substrates (110, 120, 140, 150), ink flow paths communicating with nozzles (N) are provided, and openings are made on the exposed side (+Z direction side) of the wiring substrate (150). A common ink chamber (170) is provided on the exposed surface of the wiring substrate (150) in such a way that it covers all the openings. The ink stored in the ink chamber forming member (not shown) of the common ink chamber (170) is supplied to each nozzle (N) from the opening of the wiring substrate (150).

[0094] It should be noted that, in Figure 8 The detailed description of the nozzle cone and the straight connection path of the nozzle (N) in the nozzle plate (110) described in the text is omitted.

[0095] A pressure chamber (121, ink storage section) is provided midway through the ink flow path. The pressure chamber (121) is provided to penetrate the pressure chamber substrate (120) in the vertical direction (Z direction), and the upper surface of the pressure chamber (121) is formed by a vibrating plate (130) provided between the pressure chamber substrate (120) and the separator substrate (140). For the ink in the pressure chamber (121), the vibrating plate (130) and the pressure chamber (121) are deformed by the displacement (deformation) of the piezoelectric element (160) in the storage section (141) which is provided adjacent to the pressure chamber (121) through the vibrating plate (130), thereby applying a pressure change. By applying an appropriate pressure change to the ink in the pressure chamber (121), the ink in the ink flow path is discharged from the nozzle (N) connected to the pressure chamber (121) in the form of droplets.

[0096] The support substrate (180) is bonded to the upper surface of the printhead chip (102) to hold the ink chamber forming member (not shown) of the common ink chamber (170). The support substrate (180) is provided with an opening of approximately the same size and shape as the opening on the lower surface of the ink chamber forming member (not shown). The ink in the common ink chamber (170) is supplied to the upper surface of the printhead chip (102) through the opening on the lower surface of the ink chamber forming member and the opening on the support substrate (180).

[0097] The wiring component (103), such as an FPC (Flexible Printed Circuit), is connected to the wiring substrate (150). Based on a drive signal propagating through the wiring to the wiring (151) and connecting part (152, conductive part) within the receiving part (141), the piezoelectric element (160) is displaced. The wiring component (103) extends through the support substrate (180) and is connected to the drive part (104).

[0098] The drive unit (104) receives control signals from the control unit of the inkjet recording device, power supply from the power supply unit, etc., and outputs appropriate drive signals of the piezoelectric element (160) to the wiring component (103) according to the ink discharge operation and non-discharge operation from each nozzle N. The drive unit (104) is composed of IC (Integrated Circuit) and the like.

[0099] With the above-described fluid nozzle, since the nozzle plates 10A and 10B have nozzle holes that are continuously formed with the nozzle cone 12 and the straight connecting path 13 in a position without deviation, the flow of fluid (ink, etc.) remains symmetrical, and the ejection angle is stable. Furthermore, sedimentation is difficult to occur within the nozzle, and defoaming is excellent. The stable ejection angle reduces the likelihood of poor discharge, thus improving the image quality of the inkjet recording device.

[0100] [Example]

[0101] The following describes embodiments and comparative examples of the present invention.

[0102] <Example 1>

[0103] Example 1 is an example based on the first embodiment described above. Figure 9 The reference is shown in the figure.

[0104] In process 1 ( Figure 9 In S-1), a single-crystal silicon wafer (1) with a crystal orientation of

[100] plane and a thickness of 200 μm is prepared.

[0105] In process 2 ( Figure 9 In S-2), a 2μm oxide film is formed as a mask layer 2 relative to the single-crystal silicon wafer (1) by thermal oxidation.

[0106] In process 3 ( Figure 9 In step S-3), a square opening pattern with one side of 20 μm is formed on the oxide film (2) using a positive photoresist. Then, CHF3 gas-based etching is performed using a RIE (Reactive Ion Etching) device to form a square opening pattern 3 with one side of 20 μm on the oxide film (2) in accordance with the photoresist opening pattern. Then, the photoresist is removed by immersion in acetone.

[0107] In process 4 ( Figure 9 In S-4), using a Si deep-drilling device, etching was performed using a Bosch process with SF6 and C4F8 gases to form a through hole 4 with a diameter of 20 μm on a single-crystal silicon wafer (1) with a thickness of 200 μm.

[0108] In process 5 ( Figure 9 In S-5), the oxide film 7 on the back side of the single crystal silicon wafer (1) is removed using a RIE device, and the wafer is immersed in a 40wt%·80℃ KOH aqueous solution for etching until the width of the straight connection 13 is 60μm, forming the nozzle cone 12 and the straight connection 13.

[0109] Then, using a cutting saw, 10 nozzle plates (10A) are obtained from the single-crystal silicon wafer (1) to form each nozzle plate with 2000 nozzle holes.

[0110] Using this nozzle plate, 10 inkjet heads (101) were made. Using an injection testing machine, the droplet angle of the 10 inkjet heads × 2000 nozzles at a droplet velocity of 6 m / s was measured. The result was in the range of -0.2 degrees to 0.2 degrees, and the injection angle was not a problem.

[0111] <Comparative Example 1>

[0112] After performing steps 1 to 4 as described in Example 1 above, the following steps are performed to produce the nozzle plate of Comparative Example 1. The oxide film at the bottom of the through hole 201 is removed. Figure 10 T-1), immersed in a 40wt%·80℃ KOH aqueous solution for etching, to process the diameter of the straight connecting path 202 to 60μm ( Figure 10 T-2). Then, through thermal oxidation, an oxide film 205 is formed on the inner wall of the connecting passages 202 and 203. Figure 10 T-3), using a RIE device to remove the oxide film 204 on the back side by creating an opening with a diameter of 60 μm. Figure 10 T-4), using dry etching, straight connection 206 is processed from the back side to straight connection 202. Figure 10 T-5), using hydrofluoric acid to remove the oxide film 205 ( Figure 10 T-6), and the nozzle plate 200 of Comparative Example 1 was obtained.

[0113] Then, 10 inkjet heads were fabricated in the same manner as in Example 1, and the droplet angles of the 10 printheads × 2000 nozzles at a droplet velocity of 6 m / s were measured. The results showed a range of -1.0 degrees to 1.2 degrees. Compared with Example 1, the ejection angles deteriorated.

[0114] <Example 2>

[0115] Example 2 is an example based on the second embodiment described above.

[0116] In process 6 ( Figure 4 In S-6), in process 3 ( Figure 1 After S-3), a hole 5 with a depth of 20 μm is formed by etching using a Si deep drilling device and a Bosch process using SF6 and C4F8 gases.

[0117] In process 7 ( Figure 4 In S-7), a 0.5 μm oxide film (6) is formed on the wafer (1) using thermal oxidation. Then, the oxide film on the bottom surface of the hole 5 with a depth of 20 μm is removed using a RIE device. At this time, the oxide film on the bottom surface of the hole 5 is etched first compared with the oxide film on the sidewall of the hole 5, so only the oxide film on the sidewall of the hole 5 remains.

[0118] Then, using the nozzle plate (10B) made in processes 4 and 5, 10 inkjet heads were made. Similarly, the droplet angle of the 10 printheads × 2000 nozzles at a droplet velocity of 6 m / s was measured. The result was in the range of -0.2 degrees to 0.2 degrees, and there was no problem with the ejection angle.

[0119] <Protective Film Durability Test>

[0120] Ten nozzle plates each, prepared using the same method as in Example 1 and Comparative Example 1, were used to form a Ta2O5 film, which would become a protective film for the ink, using CVD.

[0121] These nozzle plates were immersed in alkaline dyeing ink and subjected to an accelerated test at 60°C for 8 weeks (equivalent to about 2 years at 25°C). The results showed that the nozzle plate of Example 1 had no problems, but in the eight nozzle plates of Comparative Example 1, Si erosion was confirmed at the connection point of the straight connection path 202 and the straight connection path 206.

[0122] The above describes the embodiments of the present invention, but these embodiments are merely examples. Various other forms can be used to implement the invention, and the constituent elements can be omitted, replaced, or changed without departing from the spirit of the invention.

[0123] Industrial availability

[0124] This invention can be applied to a method for manufacturing a nozzle plate, a nozzle plate, and a fluid nozzle.

[0125] Symbol Explanation

[0126] 1. Single-crystal silicon substrate

[0127] 2. Mask layer

[0128] 3. Opening pattern

[0129] 4 Through holes

[0130] 5-hole section

[0131] 6. Mask layer

[0132] 10A, 10B Nozzle Plates

[0133] 11. Nozzle tip outlet

[0134] 12. Nozzle cone

[0135] 13 Straight-line connected paths

[0136] 14. Nozzle straight section

[0137] 21 Protective Film

[0138] 22 Protective film

Claims

1. A method for manufacturing a nozzle plate, which is a method for manufacturing a nozzle plate for a fluid nozzle head, wherein a nozzle plate having at least a nozzle cone and a straight connecting path in a nozzle orifice is manufactured by sequentially performing the following steps 1, 2, 3, 6, 7, 4, and 5. Step 1: The process of preparing a single-crystal silicon substrate with a crystal orientation of [100] plane. Step 2: The step of uniformly forming a mask layer on the surface of the monocrystalline silicon substrate. Step 3: The step of forming an opening pattern on the mask layer. Step 6: For the single-crystal silicon substrate located under the opening pattern, a deep etching process is performed starting from the surface to form the holes. Step 7: The step of forming a mask layer on the sidewall of the hole. Step 4: A process of forming through holes by dry etching on the surface of the single-crystal silicon substrate under the opening pattern. Step 5: Enlarging the through hole by anisotropic wet etching of the single-crystal silicon substrate, thereby forming a nozzle cone and a straight connecting path continuous with the large-diameter end of the nozzle cone on the single-crystal silicon substrate.

2. The method for manufacturing the nozzle plate according to claim 1, wherein, After step 5, a step of forming a protective film is performed, which covers the surfaces including the inside of the nozzle cone and the straight connecting path.

3. A nozzle plate for a fluid nozzle manufactured by the method of manufacturing a nozzle plate according to claim 1 or 2, having a straight connecting path composed of four [100] faces that is continuous in the direction of increasing diameter relative to the nozzle cone composed of four [111] faces of monocrystalline silicon.

4. A fluid nozzle comprising the nozzle plate of claim 3.

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