Manufacturing method of nozzle plate

Abstract

[Research Topic] To provide a method for manufacturing a nozzle plate that can simultaneously achieve high density of the nozzle opening and suitable injection characteristics. [Solution] The method for manufacturing the nozzle plate (110) includes: a first process, which is to form a first hole (305) that is connected to a first surface (Bb) of a monocrystalline silicon substrate (B) with a crystal orientation of {100} and is longer in the [100] direction than in the [010] direction, and a second hole (306) that is connected to the first hole (305) and the second surface (Ba) of the monocrystalline silicon substrate (B); and a second process, which is to enlarge the first hole (305) and the second hole (306) by anisotropic wet etching relative to the monocrystalline silicon substrate (B), thereby forming a nozzle flow path (100), the nozzle flow path (100) having a nozzle cone-shaped portion (20) having a {111} surface and a straight connecting portion (10) that is continuous with the nozzle cone-shaped portion (20).

Description

Technical Field

[0001] This invention relates to a method for manufacturing a nozzle plate. Prior Technology

[0002] In the prior art, as shown in Patent Document 1, it is well known that a nozzle plate for manufacturing the droplet ejection head of a droplet ejection device is made from a single-crystal silicon substrate. In this nozzle plate, the nozzle flow path is formed by anisotropic wet etching. [Previous Technical Documents] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent No. 5519263 Summary of the Invention

[0004] [The problem that the invention aims to solve]

[0005] However, when performing anisotropic wet etching on a single-crystal silicon substrate with a {100} crystal orientation, the etching process proceeds in a specific direction. Therefore, only a general nozzle flow path can be formed where the opening on the surface opposite the droplet ejection surface is square. If this nozzle plate is joined with another plate whose ink flow path cross-sectional shape is, for example, rectangular, the junction between the ink flow path and the nozzle flow path will have an inconsistent shape. Therefore, the impedance during ink ejection increases, necessitating an increase in the driving voltage. Furthermore, the meniscus becomes unstable, leading to deterioration of ejection characteristics such as ejection defects. Moreover, due to the limitations in the shape of the nozzle flow path, achieving a high density of nozzle openings arranged side-by-side on the single-crystal silicon substrate to ensure the volume of the nozzle flow path is difficult.

[0006] The present invention aims to solve this problem by providing a method for manufacturing a nozzle plate that can simultaneously achieve high density of nozzle openings and suitable injection characteristics. [Methods used to solve problems]

[0007] The invention described in claim 1 is a method for manufacturing a nozzle plate for a droplet ejector, comprising: a first step of forming a first hole that is connected to a first surface of a monocrystalline silicon substrate with a crystal orientation of {1 0 0} and is longer in the

[0100] direction than in the

[0010] direction, and a second hole that is connected to the first hole and the second surface of the monocrystalline silicon substrate; and a second step of enlarging the first hole and the second hole by anisotropic wet etching relative to the monocrystalline silicon substrate, thereby forming a nozzle flow path, the nozzle flow path having a nozzle cone portion having a {1 1 1} surface and a straight connecting portion continuous with the nozzle cone portion.

[0008] The invention described in claim 2 is a method for manufacturing a nozzle plate described in claim 1, wherein, in the first process described above, the length of the second hole in the

[0001] direction is formed to be approximately equal to the length of the second hole from the end of the first face to the end of the first hole in the

[0100] direction.

[0009] The invention described in claim 3 is a method for manufacturing a nozzle plate described in claim 1, wherein, in the first process described above, the length of the second hole in the

[0001] direction is formed to be longer than the length of the second hole from the end of the first surface to the end of the first hole in the

[0100] direction, and a stepped surface is formed at the nozzle cone portion.

[0010] The invention described in claim 4 is a method for manufacturing the nozzle plate described in any one of claims 1 to 3, wherein the centers of the aforementioned first hole and the aforementioned second hole are aligned with each other.

[0011] The invention described in claim 5 is a method for manufacturing the nozzle plate described in any one of claims 1 to 3, wherein, in the aforementioned first process, the bottom of the aforementioned first hole is formed into a stepped shape.

[0012] The invention described in claim 6 is a method for manufacturing a nozzle plate as described in any one of claims 1 to 3. The first process includes: forming a third hole by dry etching the single-crystal silicon substrate from the first surface to the middle of the process; forming a nozzle shielding layer along the inner surface of the third hole; and removing the nozzle shielding layer formed at the bottom of the third hole. The first hole is formed by further drilling the third hole. The second process forms a nozzle flow path having a continuous nozzle straight section from the end of the nozzle cone portion on the second surface side.

[0013] The invention described in claim 7 is a method for manufacturing a perforated plate as described in any one of claims 1 to 3, wherein the aforementioned single-crystal silicon substrate has a non-wet etched layer formed from the aforementioned second surface.

[0014] The invention described in claim 8 is a method for manufacturing the nozzle plate described in any one of claims 1 to 3, which includes: a third step of enlarging the diameter of the opening on the first side and / or the second side of the aforementioned nozzle flow path. [The effects of the invention]

[0015] According to the present invention, a method for manufacturing a nozzle plate that can simultaneously achieve high density of nozzle openings and suitable injection characteristics can be provided. Simple Explanation of the Diagram

[0016] [Figure 1] is a perspective view of a droplet ejection device equipped with a droplet ejection head formed by the deposition of a nozzle plate. [Figure 2A] is a plan view of the nozzle plate from the

[0001] direction. [Figure 2B] is a plan view of the nozzle plate from the [0 0 -1] direction. [Figure 3] is a cross-sectional view of the nozzle plate of the first embodiment from the

[0010] direction. [Figure 4] is a perspective cross-sectional view showing the nozzle flow path formed by the manufacturing method of the nozzle plate in the first embodiment. [Figure 5] is a cross-sectional view from the

[0010] direction and a plan view from the

[0001] direction, showing the manufacturing method of the nozzle plate in the first embodiment. [Figure 6A] is a cross-sectional view of the etching process in the second process observed from the

[0100] direction. [Figure 6B] is a cross-sectional view of the etching process in the second process observed from the

[0010] direction. [Figure 7A] is a cross-sectional view from the

[0010] direction of the nozzle flow path formed by offsetting the center of the opening and the nozzle in the

[0100] direction. [Figure 7B] is a cross-sectional view from the

[0010] direction of a nozzle flow path formed in such a way that the length of the nozzle in the

[0001] direction is longer than the length of the opening from the end in the

[0100] direction to the end of the nozzle on the contact surface side. [Figure 7C] is a cross-sectional view from the

[0010] direction of a nozzle flow path formed in such a way that the length of the nozzle in the

[0001] direction is shorter than the length of the opening from the end in the

[0100] direction to the end of the nozzle on the contact surface side. [Figure 8] is a cross-sectional view from the

[0010] direction and a plan view from the

[0001] direction, showing the manufacturing method of the nozzle plate in the second embodiment. [Figure 9A] is a cross-sectional view of the nozzle plate of the third embodiment from the

[0010] direction. [Fig. 9B] is a cross-sectional view of the nozzle plate of the modified example of the third embodiment from the

[0010] direction. [Figure 10] is a perspective cross-sectional view showing the nozzle flow path formed by the manufacturing method of the nozzle plate in the third embodiment. [Fig. 11] is a cross-sectional view from the

[0010] direction and a plan view from the

[0001] direction, showing the manufacturing method of the nozzle plate in the third embodiment. [Figure 12A] is a cross-sectional view of the nozzle flow path of one of the embodiments of Example 1 and the intermediate structure that forms the nozzle flow path, viewed from the

[0010] direction. [Figure 12B] is a plan view of the nozzle flow path of one of the embodiments 1 and the intermediate structure that forms the nozzle flow path, viewed from the

[0001] direction. [Figure 13A] is a cross-sectional view of the nozzle flow path of one of the embodiments 2 and the intermediate structure that forms the nozzle flow path, viewed from the

[0010] direction. [Figure 13B] is a plan view of the nozzle flow path of one of the embodiments 2 and the intermediate structure that forms the nozzle flow path, viewed from the

[0001] direction. [Figure 14A] is a cross-sectional view of the nozzle flow path of one of the embodiments 3 and the intermediate structure that forms the nozzle flow path, viewed from the

[0010] direction. [Figure 14B] is a plan view of the nozzle flow path of one of the embodiments 3 and the intermediate structure that forms the nozzle flow path, viewed from the

[0001] direction. Implementation

[0017] The following description, with reference to the drawings, outlines the ideal form of the invention. However, the scope of the invention is not limited to the examples shown in the drawings. Furthermore, in the following description, components with the same function and structure are represented by the same symbols, and their descriptions are omitted.

[0018] Furthermore, the Miller index, which describes the crystal plane or direction, is generally defined as follows, and is also applied in this specification. (hkl): A specific aspect {hkl}: Equivalent surface [hkl]: Specific direction <hkl>: Equivalent direction

[0019] Furthermore, unless otherwise specified, the embodiments described in the specification are as follows: The facet adjacent to the wafer surface: (0 0 1) facet; The ejection side of the wafer: (0 0 -1) face; The four conical surfaces that make up the conical part of the nozzle are: (1 1 1) surface, (-1 1 1) surface, (1 -1 1) surface, and (-1 -1 1) surface; The vertical surface constituting the cone-shaped part of the nozzle and the two opposing surfaces with the longer sides among the four surfaces constituting the straight connecting part: the (0 1 0) surface and the (0 -1 0) surface; Two of the four sides of the straight connecting section that are opposite each other and have shorter sides are the (1 0 0) side and the (-1 0 0) side. However, of course, as long as it is a face or direction that is equivalent to the content of the record, it is not limited to this record.

[0020] Furthermore, in the Miller index notation, as in equations 1(1) and (2) below, the symbol representing a negative exponent is generally a bar above the exponent. However, for convenience, in this specification, it is represented as in (1') and (2') below.

[0021] [Formula 1]

[0022] (h -kl)…(1') [h -kl]…(2')

[0023] [First Implementation Form] The manufacturing method of the nozzle plate 110 according to the first embodiment of the present invention will be described. The manufacturing method of the nozzle plate 110 in the first embodiment is a manufacturing method of the nozzle plate 110 (see Figure 2) installed at the droplet ejection head 2 of a droplet ejection device 1 as shown in Figure 1.

[0024] (Spray nozzle plate) The nozzle plate 110 is formed by a single-crystal silicon substrate B with a crystal orientation of {100}. Figure 2A is a plan view showing the (0 0 1) surface of the nozzle plate 110, and Figure 2B is a plan view showing the (0 0 -1) surface of the nozzle plate 110.

[0025] As shown in Figure 2B, at the nozzle plate 110, at the discharge surface (second surface) Ba ((0 0 -1) surface), a plurality of nozzle openings N are arranged in a row along the

[0010] direction. At the nozzle plate 110, a plurality of nozzle flow paths 100 are provided, which extend from the contact surface (first surface) Bb ((0 0 1) surface) to the discharge surface Ba. The nozzle plate 110 is bonded to another plate having an ink flow path at the bonding surface Bb by means of an adhesive or the like. The liquid flowing in from the ink flow path is ejected from the nozzle opening N through the nozzle flow path 100.

[0026] In addition, although only one row of nozzle openings N is shown in Figure 2B, multiple arrangements can also be made in the

[0100] direction.

[0027] Figure 3 is a cross-sectional view of the nozzle plate 110 viewed from the

[0010] direction. Figure 4 is a three-dimensional cross-sectional view of a single nozzle flow path 100. The nozzle flow path 100, as shown in Figures 3 and 4, sequentially includes a straight connecting portion 10, a nozzle cone portion 20, and a nozzle opening portion N, starting from the contact surface Bb.

[0028] {Straight connection} The straight connecting portion 10 is provided from the contact surface Bb all the way to the end of the nozzle cone portion 20 on the contact surface Bb side. That is, the straight connecting portion 10 is the opening on the contact surface Bb side of the nozzle flow path 100. The straight connecting portion 10 is constructed from one of the four faces of the {1 0 0} plane ((1 0 0) plane, (-1 0 0) plane, (0 1 0) plane, and (0 -1 0) plane). Furthermore, as shown in Figures 2A and 4, the opposite groups of faces 10a in the straight connecting portion 10 are slightly parallel.

[0029] Furthermore, as shown in Figures 2A and 4, the length of the side of the surface constituting the straight connecting portion 10, which intersects with the connecting surface Bb, along the

[0100] direction of the opposite group of surfaces 10a is longer than the length in the

[0010] direction. That is, the edge formed by the surface constituting the straight connecting portion 10 and the surface constituting the bonding surface Bb is an elongated shape, as shown in Figures 2A and 4. By forming the straight connecting portion 10 in this way, it is possible to ensure the volume of the nozzle flow path 100 while configuring the nozzle opening portion N with the narrow pitch of the short side of the elongated shape. In other words, it is possible to increase the density of the nozzle opening portion N at the nozzle plate 110.

[0030] Furthermore, while Figures 2A and 4 illustrate cases where the opening on the contact surface Bb side of the nozzle flow path 100 at the nozzle plate 110 is rectangular, this is not a limitation. When the opening on the contact surface Bb side of the nozzle flow path 100 is expanded by performing the third process (removal process) described later, the opening will definitely become rectangular. However, in this invention, the third process is not mandatory. Therefore, the opening on the contact surface Bb side of the nozzle flow path 100 at the nozzle plate 110, as long as it is elongated, can also be any shape corresponding to the shape of the opening pattern 303 described later.

[0031] [Conical part of the nozzle] The nozzle cone portion 20 has a cone-shaped surface 20a with a slightly fixed angle, which gradually widens the flow path area as it moves from the discharge surface Ba toward the contact surface Bb. More specifically, the nozzle cone portion 20 is constructed by a cone-shaped surface 20a, which is one of the four surfaces with a crystallization surface of {1 1 1} ((1 1 1) surface, (-1 1 1) surface, (1 -1 1) surface and (-1 -1 1) surface), and a portion 20b of the aforementioned four surfaces with a crystallization surface of {1 0 0}. Furthermore, the term "flow path area" in this invention refers to the cross-sectional area in a direction orthogonal to the direction in which the ink is ejected.

[0032] The angle θ1 (see Figure 3) between the conical surface 20a of the nozzle conical portion 20 and the axis parallel to the central axis of the nozzle is 15° or more. In this invention, the conical surface 20a is formed by anisotropic wet etching of a single-crystal silicon substrate B. Therefore, due to the etching characteristics of Si, the angle θ1 is 45°.

[0033] If a nozzle cone 20 is provided, even if the meniscus of the liquid retreats to the depth of the nozzle flow path 100 due to high-speed drive, the meniscus shape and droplet ejection can be stabilized.

[0034] [Nozzle opening] The nozzle opening N is provided at the discharge surface Ba, and is a circular, elliptical, or polygonal orifice for discharging droplets. The nozzle opening N is connected to the end of the nozzle cone 20 on the discharge surface Ba side.

[0035] (Manufacturing method of nozzle plate) The manufacturing method of the nozzle plate 110 includes, for example, the first to third processes shown in FIG5. In the first process, an intermediate structure 300 is formed, comprising an opening (first hole) 305 and a nozzle hole (second hole) 306, as described later. In the second process, the nozzle flow path 100 is formed by performing anisotropic wet etching on the intermediate structure 300 formed in the first process. In the third process, the nozzle plate 110 formed in the second process is subjected to a removal process.

[0036] {Project 1: Intermediate Structure Formation Project} (Project 1-1) As shown in Figure 5, the first project system is further subdivided into multiple projects. First, as part of the first step, a masking layer is formed on the surface of a single-crystal silicon substrate B. Specifically, a surface masking layer 301 is formed at the bonding surface Bb of the single-crystal silicon with a crystal orientation of {1 0 0}. Also, a back masking layer 302 is formed at the ejection surface Ba. In the following cases, when there is no special distinction between the surface masking layer 301 and the back masking layer 302, they are generally referred to as "mask layer" as described above.

[0037] The monocrystalline silicon substrate B is a plate-shaped component with a thickness of 100μm to 725μm. By using a monocrystalline nozzle as the substrate of the nozzle plate 110, it is possible to process it with high precision. As a result, a nozzle plate 110 with minimal positional errors and shape irregularities can be formed.

[0038] Furthermore, the material used to form the masking layer only needs to be able to block the etching process during the anisotropic wet etching described later. Also, it only needs to be something that will not be removed by etching. If the material meets these conditions, the material of the masking layer is not particularly limited. However, for example, oxides such as SiO2 (silicon oxide) can be used in the masking layer. Also, metal films or resins made of Al (aluminum), Cr (chromium), etc., can be used in the masking layer. In this invention, SiO2 is used as a masking layer.

[0039] Furthermore, while the thickness of the mask layer is not specifically limited, an ideal thickness is 0.1 μm to 50 μm, and an even more ideal thickness is 0.5 μm to 20 μm. The mask layer enhances the etching-stopping effect by having a thickness of 0.5 μm or more. Conversely, a mask layer with a thickness of 20 μm or less can be easily formed. However, when forming the masking layer using the aforementioned thermal oxidation method, it is ideal to set the thickness of the masking layer to 1μm to 5μm. Furthermore, the masking layer is not limited to a single-layer structure as shown in the figure, but can also be a multi-layer structure.

[0040] (Project 1-2) Next, as the first and second process, an elongated opening pattern 303 is formed at the surface masking layer 301, which becomes the opening on the bonding surface Bb side of the nozzle flow path 100. Furthermore, in this embodiment, although the shape of the opening pattern 303 is a hexagonal shape with a long side along the <1 0 0> direction, it is not limited to this. The shape of the opening pattern 303 can be any elongated shape that is longer in the

[0100] direction than in the

[0010] direction. Therefore, the shape of the opening pattern 303 can be, for example, a rectangular shape or an elliptical shape, or a shape in which a semicircle of the same width and diameter as the short side is combined with the short side of the rectangle. Specifically, firstly, a resist pattern is formed on the surface mask layer 301 using well-known photolithography technology.

[0041] <Resistant Pattern> In forming the resist pattern, either positive or negative photoresist can be used. Known materials can be used for both positive and negative photoresist. For example, ZPN-1150-90 manufactured by ZEON Corporation of Japan can be used as a negative photoresist. Furthermore, OFPR-800LB and OEBR-CAP112PM manufactured by Tokyo Ohka Kogyo Co., Ltd. can be used as positive photoresists.

[0042] The resist layer is applied and formed using a spin coater or similar method to achieve a specific thickness. Afterward, it undergoes a pre-baking process at 110°C for 90 seconds.

[0043] To improve adhesion, HMDS treatment can be applied before resist coating. HMDS treatment uses an organic material called hexamethyldisilazane, such as OAP (hexamethyldisilazane, manufactured by Tokyo Ohka Kogyo Co., Ltd.). HMDS, like resist coating, can be applied using a spin coater. Furthermore, HMDS can be expected to improve adhesion even when exposed to hexamethyldisilazane vapor.

[0044] After the resist layer is formed, it is exposed using a specific mask and an exposure machine. For example, in the case of a contact exposure machine, the exposure is performed with a light intensity of approximately 50 mJ / cm². Afterwards, it is immersed in a developing solution (e.g., NMD-3, manufactured by Tokyo Ohka Kogyo Co., Ltd., 60 to 90 seconds) to remove the photosensitive portion of the resist layer. This forms a resist pattern on the surface mask layer 301.

[0045] After the resist pattern is formed, the resist pattern is used as a mask, and the surface mask layer 301 is dry-etched to form the opening pattern 303. After the opening pattern 303 is formed, the resist pattern is removed.

[0046] Dry Etching In dry etching, RIE (Reactive Ion Etching) devices are used. Additionally, ICP (Inductively Coupled Plasma)-RIE etching devices, which employ inductive coupling in a discharge-based dry etching process, are also used. Furthermore, CHF 3 (trifluoromethane) or CF 4 (tetrafluoromethane) are used as process gases.

[0047] As one example, the RIE-100C, a dry etching apparatus manufactured by SAMCO Corporation, was used. By setting the CHF 3 gas flow rate to 80 sccm, the pressure to 3 Pa, and the RF power to 90 W, and performing etching for a specific time, an opening pattern 303 was formed.

[0048] Removal of resist patterns Furthermore, as methods for removing resist patterns, examples include wet processes using acetone or acid solutions or dry processes using aerobic plasma.

[0049] (Projects 1-3) Next, as the first to third process, the opening hole 305 is formed by dry etching the single crystal silicon substrate B under the opening pattern 303 to perform deep drilling.

[0050] (Projects 1-4) Next, as part of the first to fourth process, a nozzle pattern 304 is formed to become the nozzle opening N. The method for forming the nozzle pattern 304 is slightly the same as the method for forming the opening pattern 303 in the first and second embodiments. In addition, the nozzle pattern 304 in this embodiment is a square (rhomboid) shape with a side in the <1 1 0> direction. The nozzle pattern 304 is formed in such a way that when viewed from the contact surface Bb or even the ejection surface Ba, its center is slightly aligned with the center of the opening pattern 303. Hereinafter, this condition is set as "Condition 1".

[0051] (Projects 1-5) Next, as part of the first to fifth process, the single-crystal silicon substrate B under the nozzle pattern 304 is dry-etched to form the nozzle hole 306. The nozzle 306 is formed in such a way that its length a in the

[0001] direction is roughly the same as the length b of the nozzle 306 from the end of the bonding surface Bb side to the end of the opening 305 in the

[0100] direction. Hereinafter, this condition is set as "Condition 2".

[0052] In steps 1-5, as shown in Figure 5, it is ideal to form the nozzle hole 306 in a manner that connects to the opening hole 305. If the intermediate structure 300 connecting the opening hole 305 and the nozzle hole 306 is formed at the point in step 1, the flowability of the anisotropic wet etching solution used in step 2 will be good. Therefore, anisotropic wet etching is always performed with fresh solution. Furthermore, the hydrogen gas generated during anisotropic wet etching will be uniformly and efficiently discharged through each nozzle flow path 100. As a result, the progress of wet etching at each nozzle flow path 100 will be consistent, and a uniform nozzle flow path 100 can be formed.

[0053] However, it is not necessary for the intermediate structure 300 to be formed at the point in time of the first process to connect the opening 305 and the spray hole 306. The opening 305 and the spray hole 306 only need to be able to communicate with each other when anisotropic wet etching is performed in the second process.

[0054] Furthermore, although the above example illustrates the case where Project 1 is performed in the order of Project 1-1, Project 1-2, Project 1-3, Project 1-4, and Project 1-5, it is not a limitation. It is sufficient to meet at least three conditions: "Project 1-1 is performed initially," "Project 1-2 is performed before Project 1-3," and "Project 1-4 is performed before Project 1-5."

[0055] Therefore, condition 1, in other words, can also be said to be "when observed from the contact surface Bb and even the ejection surface Ba, the opening pattern 303 is formed in a way that makes its center slightly coincide with the center of the nozzle pattern 304".

[0056] Furthermore, condition 2, in other words, can also be described as "forming the opening 305 in a manner that makes the length b from the end in the

[0100] direction to the end of the contact surface Bb side of the nozzle 306 slightly consistent with the length a in the

[0001] direction of the nozzle 306".

[0057] {Project 2: Anisotropic Wet Etching Project} Next, as the second process, anisotropic wet etching is performed on the intermediate structure 300 formed by the first process from both sides of the bonding surface Bb and the ejection surface Ba. Figure 6A is a cross-sectional view observing the etching process in the second process from the

[0100] direction side, which forms the opening hole 305. Figure 6B is a cross-sectional view observing the etching process in the second process from the

[0010] direction, which forms the long side, which forms the opening hole 305. As shown in Figures 6A and 6B, in the second process, the opening 305 provided in the first-third processes and the nozzle 306 provided in the first-fifth processes are enlarged respectively. In this way, a nozzle flow path 100 having a nozzle cone portion 20 and a straight connecting portion 10 is formed.

[0058] Anisotropic wet etching In anisotropic wet etching, an alkaline aqueous solution is used. Specifically, it is KOH (potassium hydroxide), TMAH (tetramethylammonium hydroxide), EDP (ethylenediamine catechol), etc.

[0059] In the second process, as shown in Figure 6A, when viewed from the

[0100] direction, etching is performed on each surface constituting the opening hole 305 and the nozzle hole 306 in the

[0010] direction and the [0-10] direction. Therefore, the interval between the (0 1 0) and (0 -1 0) surfaces after anisotropic wet etching is (diameter of nozzle pattern 304 + 2 × etching amount) μm…(3).

[0060] Furthermore, as shown in Figure 6B, when viewed from the

[0010] direction, etching is performed on each surface constituting the opening 305 in both the

[0100] and [-1 0 0] directions. Also, etching is performed on each surface constituting the nozzle 306 in either the

[0100] or [-1 0 0] direction. Therefore, the interval between the (1 0 0) and (-1 0 0) surfaces after anisotropic wet etching is (diameter of nozzle pattern 304 + 6 × etching amount) μm…(4).

[0061] Specifically, the diameter of the nozzle pattern 304 is set to 10 μm, and the etching amount is set to 20 μm. Thus, the interval between the (0 1 0) surface and the (0 -1 0) surface after anisotropic wet etching, according to the above formula (3), is 10 μm + 2 × 20 μm = 50 μm. Furthermore, the interval between the (1 0 0) and (-1 0 0) surfaces after anisotropic wet etching, according to the above formula (4), is 10μm + 6×20μm = 130μm. In contrast, the diameter of the nozzle pattern 304 is set to 30 μm, and the interval between the (0 1 0) surface and the (0 -1 0) surface after anisotropic wet etching is set to 50 μm. Thus, according to the above formula (3), based on 30 μm + 2 × x μm = 50 μm, the etching amount x becomes 10 μm. The interval between the (1 0 0) and (-1 0 0) surfaces after anisotropic wet etching, according to the above formula (4), is 30μm + 6×10μm = 90μm.

[0062] As described above, from the viewpoint of increasing the density of the nozzle opening N, the nozzle flow path 100 formed by the present invention is ideally formed so that the opening on the bonding surface Bb side has an elongated shape with a difference between the size of the long side and the size of the short side. As will be described later, after the second process, when a removal process is performed as the third process in a manner that makes the straight connecting portion 10 slightly perpendicular, the interval between the (0 1 0) surface and the (0 -1 0) surface becomes the dimension of the short side of the opening on the contact surface Bb side of the nozzle flow path 100. Furthermore, the interval between the (1 0 0) surface and the (-1 0 0) surface becomes the dimension of the long side. Therefore, based on the above calculations, the nozzle pattern 304 is ideally designed to have the smallest possible diameter. However, in this embodiment, the ratio of the interval between the (0 1 0) and (0 -1 0) surfaces to the interval between the (1 0 0) and (-1 0 0) surfaces, that is, the ratio of the size of the short side to the size of the long side at the opening on the Bb side of the nozzle flow path 100 after the third process, is theoretically limited to 1:3.

[0063] {Project 3: Removal Processing Project} Returning to Fig. 5, after the second step, as the third step, removal processing such as etching, grinding, or polishing is performed on the nozzle plate 110. Specifically, for example, the removal processing is performed such that the straight connection portion 10 becomes substantially perpendicular, and the diameter of the opening on the bonding surface Bb side of the nozzle flow path 100 after anisotropic wet etching is enlarged. Or, the thickness of the nozzle plate 110 is adjusted to a desired size. Or, the mask layer is removed. [] Furthermore, particularly, even if the diameter of the nozzle pattern 304 is formed small as described above, the diameter of the nozzle opening N can be expanded by performing removal processing such as photolithography, transfer of the back mask layer 302, and etching again from the ejection surface Ba side. In addition, the third step is not a necessary step and can be appropriately performed as needed.

[0064] [Technical effects] As described above, the manufacturing method of the nozzle plate 110 of the first embodiment includes: a first step of forming an intermediate structure 300 having an opening hole (first hole) 305 that is longer in the

[0100] direction and a nozzle hole (second hole) 306 that can communicate with the opening hole 305 and the ejection surface Ba. Also, it includes: a second step of forming the nozzle flow path 100 by expanding the opening hole 305 and the nozzle hole 306 by anisotropic wet etching.

[0065] In the above configuration, regarding condition 1 and condition 2, the reason for stating "become substantially consistent" is that cases where they are not completely consistent with each other may occur due to manufacturing errors. Fig. 7A shows a case where condition 1 is not satisfied. Fig. 7B shows a case where a > b and condition 2 is not satisfied. Also, Fig. 7C shows a case where a < b and condition 2 is not satisfied. Figs. 7A to 7C all include a step at the conical surface 20a. As can be seen from the comparison of Fig. 5 and Figs. 7A to 7C, by satisfying condition 1 and condition 2, a nozzle flow path 100 with a smooth conical surface 20a is formed.

[0066] On the other hand, as shown in Figures 7A-7C, even if manufacturing errors related to condition 1 or condition 2 occur in the first process, the nozzle opening N is located at the center of symmetry of the surface between the nozzle opening N and the step difference in the conical surface 20a. This is because at least the portion of the nozzle conical portion 20 that communicates with the nozzle opening N is enlarged from the nozzle hole 306.

[0067] Therefore, according to the above manufacturing method, even if there are manufacturing errors related to condition 1 or condition 2, the nozzle cone portion 20 will definitely be formed from the nozzle hole 306. Furthermore, the nozzle opening portion N is not located at the center of symmetry between the nozzle opening portion N and the step difference, which is positioned within the cone surface 20a without any deviation in position. Therefore, even if there are manufacturing errors related to condition 1 or condition 2, it is possible to form a nozzle plate 110 with a nozzle flow path 100 that "does not become eccentric, maintains the symmetry of liquid flow, and has a stable ejection angle."

[0068] Furthermore, according to the above manufacturing method, it is possible to form a nozzle plate 110 having a nozzle flow path 100 with an elongated opening at the bonding surface Bb. Therefore, the nozzle opening N can be highly densed at the nozzle plate 110. Also, when the nozzle plate 110 is joined with other plates whose ink flow path has an elongated cross-sectional shape, the joint between the nozzle flow path 100 and the ink flow path will have a consistent shape, thus achieving suitable injection characteristics.

[0069] [Regarding the composition of other ideals] As described above, the opening pattern 303 is not limited to a hexagonal shape with a long side along the <1 0 0> direction. Similarly, the nozzle pattern 304 is not limited to a square shape with a side along the <1 1 0> direction. However, considering the orientation dependence of anisotropic wet etching, it is particularly ideal for the opening pattern 303 and the nozzle pattern 304 to be set to the above-described shapes. If set to the above-described shapes, anisotropic wet etching as shown in Figure 5 can easily occur.

[0070] Furthermore, Figures 7A to 7C illustrate cases where manufacturing errors related to conditions 1 or 2 occur during the first process. Among these, the nozzle flow path 100 shown in Figure 7B, which is generally "a>b and has a stepped vertical surface at the nozzle cone portion 20, or even a steeper inclined surface (step surface) with an angle θ1," has better meniscus stability. This is because if such a stepped surface is formed, even if the meniscus retreats all the way to the depth of the nozzle flow path 100, the expansion in the

[0100] direction is suppressed, and the width and length in the

[0100] direction are consistent with each other.

[0071] Alternatively, ideally, the stepped surface is formed in such a way that the length from the ejection surface Ba to the end of the bonding surface Bb of the stepped surface is more than 20 μm and less than 60 μm. This is because, occasionally, the amount of liquid retreat may be greater than 20 μm. Also, it is because if the aforementioned length is longer than 60 μm, the nozzle flow path 100 may not be able to ensure sufficient volume.

[0072] [Second Implementation] Next, the manufacturing method of the nozzle plate 110 according to the second embodiment of the present invention will be described. In the second embodiment, after the opening pattern 303 is formed, a stepped opening 305 is formed by further forming patterns of different sizes and thicknesses.

[0073] Figure 8 illustrates the manufacturing method of the nozzle plate 110 in the second embodiment. Furthermore, regarding Project 1-1, since it is the same as the first implementation, its detailed description is omitted.

[0074] (Project 1-2a) In this embodiment, as the first-2a process, the resist pattern is formed and dry etching is performed twice. Specifically, after the opening pattern 303 is formed, a resist pattern of a general size that surrounds the opening pattern 303 is formed. Furthermore, dry etching is performed with a smaller etching amount than that of the opening pattern 303 to form the sub-pattern 303a. After the opening pattern 303 and the sub-pattern 303a are formed, the resist pattern is removed.

[0075] (Projects 1-3) After the opening pattern 303 and the sub-pattern 303a are formed, the opening hole 305 is formed by dry etching to perform deep drilling. At this point, at sub-pattern 303a, the surface masking layer 301 is first etched. Once the etching of the surface masking layer 301 is complete, the monocrystalline silicon substrate B is etched. On the other hand, at the opening pattern 303, there is no surface masking layer 301. Therefore, the monocrystalline silicon substrate B is immediately etched.

[0076] Therefore, even if etching is performed at the same time, the etching amount of the monocrystalline silicon substrate B is different at the opening pattern 303 and the sub-pattern 303a. That is, the monocrystalline silicon substrate B under the opening pattern 303 will be etched to a deeper depth. As a result, as shown in Figure 8, an opening hole 305 with a stepped bottom is formed. Furthermore, regarding the steps formed in the first-third embodiment, ideally, they should be designed such that the length c in the

[0001] direction and the length d in the

[0100] direction are a≒b≒c≒d. Similar to the first embodiment, if this condition is met, the cone-shaped surface 20a is formed as a smooth nozzle flow path 100.

[0077] (Projects 1-4, 1-5, Project 2, Project 3) After the opening 305 is formed, the nozzle 306 is formed by processes 1-4 and 1-5. Then, in the second process, the nozzle flow path 100 is formed by anisotropic wet etching. After the second process, as the third process, it is appropriate to carry out the removal process.

[0078] [Technical Effects] As shown above, the manufacturing method of the nozzle plate 110 in the second embodiment is to form an opening 305 with a stepped bottom by forming a sub-pattern 303a with a different size and thickness from the opening pattern 303. Based on this configuration, the ratio of the dimension of the short side to the dimension of the long side at the opening on the contact surface Bb side of the nozzle flow path 100 can be set to be larger than 1:3. Therefore, it is possible to further increase the density of the nozzle opening N.

[0079] [Variation Example] Furthermore, although in the above configuration, the sub-pattern 303a is formed after the opening pattern 303 is formed, it is not limited to this and the order can also be reversed. Furthermore, although the above configuration is an example of forming a resist pattern and dry etching twice, it is not limited to this. That is, it is also possible to form an opening 305 with multiple steps by forming a resist pattern and dry etching more than twice. Furthermore, although the above configuration is an example of forming resist patterns and dry etching multiple times, it is not limited to this. That is, the opening pattern 303 and the sub-pattern 303a can also be formed at once by using a grayscale mask.

[0080] [Third Implementation Form] Next, the manufacturing method of the nozzle plate 110 according to the third embodiment of the present invention will be described with reference to FIG11. The manufacturing method of the nozzle plate 110 in the third embodiment is to form a nozzle flow path 100 having a nozzle straight section 30 as shown in FIG9 and FIG10.

[0081] {Straight section of nozzle} The straight section 30 of the nozzle is a flow path that makes the discharge surface Ba side continuous with the nozzle opening N and the contact surface Bb side continuous with the nozzle cone section 20.

[0082] Furthermore, the following example illustrates a straight section 30 of a nozzle formed by a plane with an angle of 0° between it and an axis parallel to the nozzle center axis, as shown in Figure 9A. However, it is not limited to this example. As shown in Figure 9B, the angle θ2 between the "surface constituting the straight section 30 of the nozzle" and the "axis parallel to the central axis of the nozzle" is approximately constant regardless of the location, and is 0°≦θ2<15°.

[0083] In this embodiment, the first-A to the first-C processes are performed sequentially, at least after the first-4 processes and before the first-5 processes. In this embodiment, the order of the processes is not particularly limited as long as at least the following three conditions are met: "the first-1 process is performed initially" and "the first-2 process is performed before the first-3 process". However, in practice, it is ideal to perform Projects 1-A to 1-C before Projects 1-3. This is because if Project 1-B, which will be described later, is performed after Projects 1-3, a shielding layer will also be formed at the opening 305, which will then require the removal of that shielding layer. Therefore, the following is assumed to be carried out in the order of Project 1-1 → Project 1-4 → Project 1-A → Project 1-B → Project 1-C → Project 1-5 → Project 1-2 → Project 1-3 → Project 2 → Project 3. Furthermore, since Projects 1-1 to 1-5 are identical to the first implementation, detailed descriptions are omitted.

[0084] (Project 1-A) After the nozzle pattern 304 is formed through processes 1-4, as process 1-A, a specific amount of dry etching is performed on the single-crystal silicon substrate B under the nozzle pattern 304. This forms the nozzle straight hole (third hole) 307. In this process, only the predetermined length of the nozzle straight portion 30 needs to be etched.

[0085] (Project 1-B) After the formation of the straight nozzle hole 307, as part of Project 1-B, a nozzle shielding layer 308 is formed along the inner surface of the straight nozzle hole 307. The method of forming the nozzle shielding layer 308 is the same as that of the shielding layer in terms of material and formation method.

[0086] (Project 1-C) After the nozzle masking layer 308 is formed, as part of process 1-C, the nozzle masking layer 308 formed at the bottom of the nozzle straight hole 307 is removed. The nozzle masking layer 308 at the bottom of the nozzle straight hole 307 can be removed by dry etching using a RIE device or the like. However, due to the verticality of the etchant, the nozzle masking layer 308 formed on the side is more difficult to remove during dry etching compared to the bottom. Therefore, the nozzle masking layer 308 formed at the bottom of the nozzle straight hole 307 is etched first, while the nozzle masking layer 308 formed on the side remains.

[0087] Alternatively, by setting the etching conditions in the process to low pressure or high bias, the nozzle mask layer 308 on the side can be made more difficult to etch.

[0088] (Projects 1-5, 1-2, and 1-3) Following process 1-C, as process 1-5, the nozzle hole 306 is formed by further etching the single-crystal silicon substrate B to create the straight hole 307. Then, the opening hole 305 is formed through processes 1-2 and 1-3.

[0089] (Project 2, Project 3) Next, as the second process, anisotropic wet etching is performed. At this time, the side surface of the nozzle straight hole 307 is protected by the nozzle masking layer 308. Therefore, the etching of the side surface of the nozzle straight hole 307 is suppressed and remains as the nozzle straight portion 30. After the second process, a removal process is suitable as the third process. In addition, in this embodiment, the nozzle masking layer 308 can also be removed together with the masking layer in the third process.

[0090] [Technical Effects] As shown above, the manufacturing method of the nozzle plate in the third embodiment includes: steps 1-A to 1-C, which form a nozzle with a straight hole 307 and a nozzle shielding layer 308. Based on this configuration, a nozzle flow path 100 having a nozzle straight section 30 can be formed. The nozzle straight section 30 increases the resistance during droplet ejection, thereby suppressing meniscus vibration and stabilizing the meniscus shape. Therefore, a nozzle plate 110 having a nozzle flow path 100 that improves ejection stability can be formed.

[0091] [Variation Example] Furthermore, although the above configuration is an example of forming the straight section 30 of the nozzle by forming the straight hole 307 of the nozzle and the nozzle shielding layer 308, it is not limited to this. Even when using a single-crystal silicon substrate B with a non-wet etching layer that is etch-resistant, it is possible to form the straight section 30 of the nozzle.

[0092] The term "non-wet etch layer" refers to, for example, a layer with etching resistance that can be formed by masking, thermal oxidation, or high-concentration boron doping. Alternatively, a quartz layer formed by means other than thermal oxidation can be deposited on a single-crystal silicon substrate B, and this quartz layer can be designated as a non-wet etch layer.

[0093] Specifically, firstly, a non-wet etching layer of the same thickness as the nozzle plate 110 is formed on at least the ejection surface Ba side of the monocrystalline silicon substrate B. Then, if this monocrystalline silicon substrate B is used to form the nozzle holes 306 and anisotropic wet etching is performed, the non-wet etching layer functions the same as the nozzle masking layer 308. Therefore, even when using a single-crystal silicon substrate B with a non-wet etched layer, a straight section 30 of the nozzle can be formed at the nozzle flow path 100.

[0094] Furthermore, regarding the "length a of the

[0001] direction of the nozzle hole 306" in condition 2, it obviously does not include the length of the

[0001] direction of places with etching resistance, such as the nozzle masking layer 308 or the non-wet etching layer.

[0095] Furthermore, in the manufacturing process of each embodiment, in order to make the nozzle plate 110 usable for a long time, it is also possible to add a process of forming at least one protective film. In this case, after the second or third process, a process is carried out to form a protective film covering at least a portion of the surface containing the nozzle flow path 100.

[0096] As a protective film, materials that will not dissolve due to contact with ink can be selected, such as metal oxide films (tantalum pentoxide, hafnium oxide, niobium oxide, titanium oxide, zirconium oxide, etc.), metal silicate films containing silicon in the metal oxide film (tantalum silicate, hafnium silicate, niobium silicate, titanium silicate, zirconium silicate, etc.), SiC (silicon carbide) films, DLC (diamond-like carbon) films, or materials used in the formation of the masking layer. Furthermore, organic films such as polyimide, polyamide, and parylene can also be used as protective films. The thickness of the protective film is not specifically limited, but it can be set to, for example, 0.05μm to 20μm. [Example]

[0097] Hereinafter, the results of evaluating the ideal configuration will be described with reference to embodiments and comparative examples of the present invention. The present invention will be specifically described below through embodiments; however, the present invention is not limited to these embodiments.

[0098] [Sample Creation] A nozzle plate 110 with 1280 nozzle flow paths 100 formed in the manner described in the following embodiments and comparative examples is manufactured. Then, it is joined with a piezoelectric plate having an ink flow path whose opening at the contact surface has the same shape as the opening on the contact surface Bb side of the nozzle flow path 100, thus forming an inkjet head 2, which is a droplet ejector. This inkjet head is then mounted on an inkjet recording device 1, which is a droplet ejector.

[0099] Figures 12-14 illustrate the nozzle flow path 100 of one of the nozzle plates 110 in each embodiment. In each figure, the dashed lines show the intermediate structure 300 formed in the first process. The solid lines show the nozzle flow path 100 in which "anisotropic wet etching is performed on the intermediate structure 300 in the second process, and removal processing is performed in the third process in a manner that makes the straight connecting portion 10 slightly perpendicular, and the opening on the bonding surface Bb side is set to a rectangular shape".

[0100] (Example 1) Based on the manufacturing method of the second embodiment, the nozzle plate 110 is formed. That is, as shown in Figures 12A and 12B, an intermediate structure 300 with a stepped bottom of the opening 305 is formed. Then, a nozzle flow path 100A is formed, which includes a nozzle cone portion 20A, a straight connecting portion 10A, and a nozzle opening portion N.

[0101] Furthermore, as shown in Figure 12B, the shape of the opening pattern 303 is hexagonal when viewed in planar view. Also, the dimensions of the opening on the contact surface Bb side of the nozzle flow path 100A are 50μm × 130μm, and the nozzle opening N is a circle with a diameter of 30μm. Furthermore, the intermediate structure 300 formed in the first process is designed in a manner that would form a≒b≒c≒d.

[0102] (Example 2) Based on the manufacturing method of the third embodiment, a nozzle plate 110 is formed. That is, as shown in Figures 13A and 13B, a nozzle flow path 100B is formed, which includes a nozzle straight section 30B, a nozzle cone section 20B, a straight connecting section 10B, and a nozzle opening section N.

[0103] Furthermore, as shown in Figure 13B, the shape of the opening pattern 303 is a combination of a semicircle with the same diameter and width as the short side of a rectangle. Also, the dimensions of the opening on the contact surface Bb side of the nozzle flow path 100B are 50μm × 130μm. Furthermore, the length of the straight section 30B of the nozzle in the

[0001] direction is 30μm. Also, as shown in Figures 13A and 13B, in this embodiment, a circular nozzle pattern 304 with a diameter of 10μm is formed in the first to fourth steps, and in the third step, it is expanded in a way that makes the nozzle opening N a circular shape with a diameter of 30μm.

[0104] Furthermore, regarding condition 2, it was designed so that a>b. Therefore, it is formed with a vertical surface (step surface) with a length of 10μm in the

[0001] direction at the cone surface 20aB of the nozzle cone portion 20B.

[0105] (Example 3) Based on the manufacturing method of the third embodiment, a nozzle plate 110 is formed. That is, as shown in Figures 14A and 14B, a nozzle flow path 100C is formed, which includes a nozzle straight section 30C, a nozzle cone section 20C, a straight connecting section 10C, and a nozzle opening section N.

[0106] Furthermore, as shown in FIG14B, the shape of the opening pattern 303 is a rectangular shape with a longer length in the

[0010] direction compared to the length in the

[0100] direction. Also, the size of the opening on the bonding surface Bb side of the nozzle flow path 100C is 50μm × 130μm. Furthermore, as shown in FIG14A and FIG14B, in this embodiment, a rhomboid nozzle pattern 304 with a diameter of 10μm is formed in the first to fourth steps, and in the third step, it is expanded in a way that makes the nozzle opening N a circular shape with a diameter of 30μm.

[0107] Furthermore, regarding condition 2, it was designed so that a=b. Therefore, a stepped surface was not formed at the conical surface 20aC of the nozzle cone portion 20C. Furthermore, the straight section 30C of the nozzle is appropriately etched during the expansion process of the nozzle opening. Therefore, the straight section 30C of the nozzle has a conical surface with an angle θ 2 of 8°, a length of 35 μm in the

[0001] direction, and a diameter of 40 μm at the end of the bonding surface Bb side.

[0108] (Comparative Example 1) The nozzle flow path 100 is formed using a method known in the prior art. That is, although it has a nozzle cone-shaped portion 20 and a straight connecting portion 10, the opening on the contact surface Bb side of the nozzle flow path 100 is a square shape of 50μm×50μm.

[0109] The following tests 1 and 2 were conducted using an inkjet recording device equipped with an inkjet head having the nozzle plate 110 of Examples 1-3 and Comparative Example 1 described above.

[0110] [Experiment 1, Launch Angle Test] By using a driving voltage that results in an average droplet velocity of approximately 6 m / s, UV ink that has been heated to a viscosity of 8 cP is ejected. At this point, the ejection angle, which is the angle between the nozzle center axis and the ejected liquid, is evaluated to be within ± a few degrees for 1280 nozzles.

[0111] [Experiment 2, Maximum Speed ​​Test] By using a drive frequency of 40kHz, the ejection velocity of UV ink heated to a viscosity of 8cP was increased from 5 m / s. Then, the ejection velocity at which "ejection defects occur at nozzle opening N" was measured, defined as the ejection velocity occurring at 5 or more nozzles out of 100 nozzles. Furthermore, when the ejection velocity was 9 m / s or higher, ejection defects were difficult to occur even at high ejection velocities. Moreover, if the ejection velocity was 11 m / s, it was considered ideal because ejection defects were even less likely to occur. Therefore, for meniscus stability, speeds of less than 9 m / s were rated "C", speeds of 9 m / s to less than 11 m / s were rated "B", and speeds of 11 m / s or higher were rated "A".

[0112] The results of Experiment 1 and Experiment 2 are shown in Table I.

[0113]

[0114] [evaluate] If Example 1 is compared with Comparative Example 1, the meniscus stability of Example 1 is better and ejection defects are less likely to occur. This is because Example 1 has a nozzle cone 20A that is generally formed such that "the center of the nozzle opening N is located at the symmetrical center of the cone 20aA".

[0115] Furthermore, when comparing Examples 1, 2, and 3, Examples 2 and 3 are superior because they further increase the ejection angle and improve the ejection characteristics. This is because straight nozzle portions 30B and 30C are formed at the nozzle flow path 100.

[0116] Furthermore, comparing Example 2 with Example 3, the meniscus stability of Example 2 is superior, and ejection defects are less likely to occur. This is because a stepped surface is formed at the conical surface 20aB of the nozzle cone portion 20B.

[0117] 2: Droplet ejection head 10: Straight connection part 20: Conical part of the nozzle 30: Straight section of the nozzle 100: Nozzle Flow Path 110: Spray nozzle plate 305: Opening Hole (Hole 1) 306: Blowhole hole (2nd hole) 307: Straight-line nozzle hole (3rd hole) 308: Nozzle shielding layer N: Nozzle opening B: Single-crystal silicon substrate Ba: Spit out the noodles (side 2) Bb: Following the first side (page 1)

Claims

1. A method for manufacturing a nozzle plate, which is a method for manufacturing a nozzle plate for a droplet ejector head, and includes: a first step of forming a first hole that is connected to a first surface of a monocrystalline silicon substrate with a crystal orientation of {1 0 0} and is longer in the [1 0 0] direction than in the [0 1 0] direction, and a second hole that is connected to the first hole and a second surface of the monocrystalline silicon substrate; and a second step of enlarging the first hole and the second hole by anisotropic wet etching relative to the monocrystalline silicon substrate, thereby forming a nozzle flow path, the nozzle flow path having a nozzle cone portion having a {1 1 1} orientation and a straight connecting portion continuous with the nozzle cone portion.

2. The method for manufacturing the nozzle plate as described in claim 1, wherein, In the aforementioned first project, the length of the aforementioned second hole in the [0 0 1] direction is formed to be approximately equal to the length of the aforementioned second hole from the end of the aforementioned first face to the end of the aforementioned first hole in the [1 0 0] direction.

3. The method for manufacturing the nozzle plate as described in claim 1, wherein, In the aforementioned first project, the length of the aforementioned second hole in the [0 0 1] direction is formed to be longer than the length of the aforementioned second hole from the end of the aforementioned first surface side to the end of the aforementioned first hole in the [1 0 0] direction, and a stepped surface is formed at the aforementioned nozzle cone portion.

4. A method for manufacturing the nozzle plate as described in any of claims 1 to 3, wherein, The center systems of the aforementioned hole 1 and the aforementioned hole 2 are consistent.

5. A method for manufacturing the nozzle plate as described in any of claims 1 to 3, wherein, In the aforementioned first project, the bottom of the aforementioned first hole was formed into a stepped shape.

6. A method for manufacturing the nozzle plate as described in any of claims 1 to 3, wherein, The aforementioned first process includes: forming a third hole by dry etching the aforementioned single-crystal silicon substrate from the aforementioned first surface to the end of the process; forming a nozzle shielding layer along the inner surface of the aforementioned third hole; and removing the aforementioned nozzle shielding layer formed at the bottom of the aforementioned third hole. The aforementioned first hole is formed by further drilling the aforementioned third hole. The aforementioned second process forms a nozzle flow path having a continuous nozzle straight section starting from the end of the aforementioned nozzle cone portion on the aforementioned second surface side.

7. A method for manufacturing the nozzle plate as described in any of claims 1 to 3, wherein, The aforementioned single-crystal silicon substrate has a non-wet etched layer formed from the aforementioned second surface.

8. A method for manufacturing the nozzle plate as described in any of claims 1 to 3, wherein, The system includes: a third process, which is to enlarge the diameter of the opening on the first side and / or the second side of the aforementioned nozzle flow path.

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